272 results on '"Jeffrey A. Bell"'
Search Results
102. The Standardized Work Field Guide
- Author
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Timothy D. Martin, Jeffrey T. Bell, and Scott A. Martin
- Published
- 2017
103. Avian malaria, ecological host traits and mosquito abundance in southeastern Amazonia
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Christian B. Andretti, Jason D. Weckstein, Alan Fecchio, Jeffrey A. Bell, Fernando M. d’Horta, Allan M. Silva, Vincenzo A. Ellis, and Vasyl V. Tkach
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0106 biological sciences ,0301 basic medicine ,Plasmodium ,Physiology ,Population Dynamics ,Biodiversity ,Protozoan Proteins ,Parasite diversity ,01 natural sciences ,Mosquito ,Dry season ,Prevalence ,Real-time Polymerase Chain Reaction ,Animals Dispersal ,Phylogeny ,Microbial Diversity ,Mosquito Vector ,Cytochrome b ,Ecology ,Amazon rainforest ,Host ,Cytochromes b ,Infectious Diseases ,Homogeneous ,Population Abundance ,Priority Journal ,Female ,Seasons ,Animals Experiment ,Transmitted disease ,Brazil ,Malaria, Avian ,Animals Model ,Mosquito Vectors ,Cytochromes B ,Biology ,010603 evolutionary biology ,Host Specificity ,Birds ,03 medical and health sciences ,Bird ,Unindexed Sequence ,Avian malaria ,Animals Tissue ,parasitic diseases ,Genetics ,medicine ,Animals ,Amino Acid Sequence ,Controlled Study ,Host Range ,Protozoal Protein ,Animal ,Brasil ,Cytochrome B ,Nucleotide Sequence ,Animals Distribution ,Microorganism Detection ,Nonhuman ,medicine.disease ,030104 developmental biology ,Culicidae ,Haemoproteus ,Species Identification ,Animal Science and Zoology ,Parasitology ,Season ,Animal Distribution - Abstract
SUMMARYAvian malaria is a vector transmitted disease caused byPlasmodiumand recent studies suggest that variation in its prevalence across avian hosts is correlated with a variety of ecological traits. Here we examine the relationship between prevalence and diversity ofPlasmodiumlineages in southeastern Amazonia and: (1) host ecological traits (nest location, nest type, flocking behaviour and diet); (2) density and diversity of avian hosts; (3) abundance and diversity of mosquitoes; and (4) season. We used molecular methods to detectPlasmodiumin blood samples from 675 individual birds of 120 species. Based on cytochromebsequences, we recovered 89 lineages ofPlasmodiumfrom 136 infected individuals sampled across seven localities.Plasmodiumprevalence was homogeneous over time (dry season and flooding season) and space, but heterogeneous among 51 avian host species. Variation in prevalence among bird species was not explained by avian ecological traits, density of avian hosts, or mosquito abundance. However,Plasmodiumlineage diversity was positively correlated with mosquito abundance. Interestingly, our results suggest that avian host traits are less important determinants ofPlasmodiumprevalence and diversity in southeastern Amazonia than in other regions in which they have been investigated.
- Published
- 2017
104. Host associations and turnover of haemosporidian parasites in manakins (Aves: Pipridae)
- Author
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Izeni Pires Farias, Iubatã P. de Faria, John G. Blake, Christopher C. Witt, Joe Tobias, Rebeka Fanti, Alan Fecchio, Jeffrey A. Bell, Vasyl V. Tkach, Robert E. Ricklefs, Maria Svensson-Coelho, Matthew C. I. Medeiros, John M. Bates, Elyse D. Coffey, Jason D. Weckstein, Christopher H. Trisos, João Batista de Pinho, Marina Anciães, Gabriel M. F. Felix, Vincenzo A. Ellis, Érika Martins Braga, and Bette A. Loiselle
- Subjects
0106 biological sciences ,0301 basic medicine ,Plasmodium ,Lineage (evolution) ,Protozoan Proteins ,Mycology & Parasitology ,01 natural sciences ,Prevalence ,Manakin ,SPATIAL VARIATION ,Passeriformes ,Protozoan Infections, Animal ,Phylogeny ,AVIAN MALARIA PARASITES ,biology ,SPECIES RICHNESS ,Cytochromes b ,BETA DIVERSITY ,Passerine ,Infectious Diseases ,GEOGRAPHICAL DISTANCE ,SIMILARITY ,Avian malaria ,host switching ,parasite diversity ,Life Sciences & Biomedicine ,host turnover ,Panama ,Zoology ,010603 evolutionary biology ,Host-Parasite Interactions ,03 medical and health sciences ,MISSING DATA ,biology.animal ,medicine ,Animals ,Science & Technology ,NEOTROPICAL SAVANNA ,0707 Veterinary Sciences ,Bird Diseases ,BLOOD PARASITES ,Haemosporida ,South America ,biology.organism_classification ,medicine.disease ,Malaria ,Genetic divergence ,030104 developmental biology ,parasite community ,Biological dispersal ,community assembly ,Animal Science and Zoology ,Haemoproteus ,Parasitology - Abstract
SUMMARYParasites of the generaPlasmodiumandHaemoproteus(Apicomplexa: Haemosporida) are a diverse group of pathogens that infect birds nearly worldwide. Despite their ubiquity, the ecological and evolutionary factors that shape the diversity and distribution of these protozoan parasites among avian communities and geographic regions are poorly understood. Based on a survey throughout the Neotropics of the haemosporidian parasites infecting manakins (Pipridae), a family of Passerine birds endemic to this region, we asked whether host relatedness, ecological similarity and geographic proximity structure parasite turnover between manakin species and local manakin assemblages. We used molecular methods to screen 1343 individuals of 30 manakin species for the presence of parasites. We found no significant correlations between manakin parasite lineage turnover and both manakin species turnover and geographic distance. Climate differences, species turnover in the larger bird community and parasite lineage turnover in non-manakin hosts did not correlate with manakin parasite lineage turnover. We also found no evidence that manakin parasite lineage turnover among host species correlates with range overlap and genetic divergence among hosts. Our analyses indicate that host switching (turnover among host species) and dispersal (turnover among locations) of haemosporidian parasites in manakins are not constrained at this scale.
- Published
- 2017
105. Complex Reaction Dynamics in the Cerium–Bromate–2-Methyl-1,4-hydroquinone Photoreaction
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Jeffrey G. Bell, Jichang Wang, and James R. Green
- Subjects
Hydroquinone ,Substrate (chemistry) ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,Bromate ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Cerium ,chemistry ,Reaction dynamics ,Reactivity (chemistry) ,Physical and Theoretical Chemistry ,0210 nano-technology ,Spectroscopy ,Methyl group - Abstract
Spontaneous oscillations with a long induction time were observed in the bromate-2-methyl-1,4-hydroquinone photoreaction in a batch reactor, where removal of illumination effectively quenched any reactivity. A substantial lengthening of the oscillatory window and a dramatic increase in the complexity of the reaction behavior arose upon the addition of cerium ions, in which separate bifurcation regions and mixed mode oscillations were present. The complexity has a strong dependence on the intensity of illumination supplied to the system and on the initial concentrations of the reactants. (1)H NMR spectroscopy measurements show that the photoreduction of 2-methyl-1,4-benzoquinone leads to the formation of 2-methyl-1,4-hydroquinone and the compound 2-hydroxy-3-methyl-1,4-benzoquinone. Spectroscopic investigation also indicates that the presence of methyl group hinders the bromination of the studied organic substrate 2-methyl-1,4-hydroquinone, resulting in the formation of 2-methyl-1,4-benzoquinone.
- Published
- 2014
106. Outcomes of patients with low-risk endometrial cancer surgically staged without lymphadenectomy based on intra-operative evaluation
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Jeffrey G. Bell, Gary C. Reid, Michelle Harvison, Jennifer Klima, Diana M. Patterson, and Kellie S. Rath
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Adult ,medicine.medical_specialty ,medicine.medical_treatment ,Disease ,Risk Assessment ,medicine ,Humans ,Lymph node ,Pathological ,Aged ,Neoplasm Staging ,Retrospective Studies ,Aged, 80 and over ,Intraoperative Care ,business.industry ,Endometrial cancer ,Obstetrics and Gynecology ,Cancer ,Histology ,Middle Aged ,medicine.disease ,Endometrial Neoplasms ,Surgery ,Dissection ,Treatment Outcome ,medicine.anatomical_structure ,Oncology ,Lymph Node Excision ,Female ,Lymphadenectomy ,business ,Algorithms - Abstract
The objective of the study was to evaluate clinical outcomes in patients with stage I endometrial cancer undergoing surgical management without lymphadenectomy based on intra-operative assessment for low-risk disease.Between 2000 and 2009, a total of 179 patients were surgically staged without lymphadenectomy for low-risk stage I endometrial cancer. Low-risk cancer was defined by intra-operative criteria based on both gross and frozen tissue microscopic evaluation: 1) G1 or G2 endometrioid histology; 2) myoinvasion50%; 3) no cervical disease, and 4) no intra-abdominal metastasis. Records were reviewed for postoperative complications, pathological diagnoses, adjuvant radiation treatment, cancer recurrence, and mortality.Morbidity, cancer recurrence, and disease-specific mortality were low. Postoperative complications occurred in 5 patients (2.8%). Nine patients (5.0%) were offered adjuvant radiation for higher risk disease diagnosed on final pathology. Radiation morbidity was minimal: grade 1 vaginal toxicity in 2 patients. Three patients (1.7%) experienced recurrent cancer with mean time to recurrence of 43.7 months. Five year overall survival was 95.8%. The five year probability of disease-specific death was 1.1%.In an institution with reliable capability of pathological frozen tissue diagnosis, omission of lymph node dissection is a reasonable option in the surgical management of those patients with low-risk disease diagnosed by intra-operative factors.
- Published
- 2014
107. Experiments in Thinking
- Author
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Jeffrey A. Bell
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Psychoanalysis ,media_common.quotation_subject ,Philosophy ,Passions ,Demise ,Epistemology ,Power (social and political) ,Feeling ,Natural (music) ,Conversation ,Empiricism ,Objectivity (science) ,media_common - Abstract
Experiments in Thinking: An Assay of Smith's Essays on Deleuze Daniel W. Smith, Essays on Deleuze (Edinburgh: Edinburgh University Press, 2012),Let me begin with a hypothetical. Let us take a relatively established philosopher who has been at work within his particular sub-discipline for a number of years. He has produced some good work and when at conferences a few people actually recognize the name on his nametag. Things are good and the future looks even better. Brimming with confidence, our philoso- pher brings his latest work to a conference, fully expecting this will be the essay that brings him to the next level. While at the bar the night before presenting his paper, a good friend and colleague tells about the work of another philosopher that addresses many of the same themes he does, but in a much more interesting way. Our philosopher is caught off guard and a flood of questions is forced upon him: Who is it? How is this possible? How much has she written? Where and when did she write it? And with whom is she associated, and where does that leave our philosopher?1 Our philosopher's questions go unanswered, for his friend has to rush off to meet someone else. Who?, he wonders. So there he sits, our woeful academic, finding himself adrift, like Proust's jealous lover, "living within a prob- lem, and constrained, involuntarily, to explore its conditions" (Essays 84). It is this problematic state, Deleuze argues, that forces one to think; it is the objectivity of what is not known, the "objective dimension of the problem" (ibid. 300),or what Deleuze refers to as the "natural 'powerlessness' which is indistinguishable from the greatest power"-that is, the power of thinking.2Associated with thinking, however, and with the conditions of the problem that force it upon us, is delirium. "Underneath all reason," Deleuze writes, "lies delirium, and drift."3 Take Hume, for instance, who Deleuze believes holds that "if the mind is manifested as a delirium, it is because it is first of all, and essentially, madness."4 We can begin to see why this is so, for if thought is forced upon us by the objectivity of the problem, by the questions that impinge upon the jealous lover or academic for instance, then the pursuit of the questions may well undermine all that is common and familiar and unleash a madness that remains inseparable from each of our rational, well-tuned thoughts. Hume was well aware of this fact when in the Treatise he noted that "a lively imagination very often degenerates into madness or folly, and bears it a great resemblance," since for the mad personevery loose fiction or idea, having the same influence as the impressions of the memory, or the conclusions of the judgment, is receiv'd on the same foot- ing, and operates with equal force on the passions. A present impression and a customary transition are now no longer necessary to inliven our ideas.5We can now return to our jealous philosopher, thrown as she was into a frenzied state of exploring the objective conditions of the problem she encountered upon hearing about the existence of a rival. The forced thinking this brings about, as thinking, risks becoming undone. Our philosopher can become unhinged. Rather than thinking in terms of already established associations and memories-or what Hume identifies as the "customary transition" from one thought to an- other-she is "inlivened" to conclusions on the least provocation. For example, she spots John Protevi in conversation with someone she does not recognize, but rather than assume all is well-after all, John has been a friend for years-she leaps to the conclusion that John and the stranger are plotting her demise. This undermining then spreads, unchecked, and everywhere she turns the familiar associations take on a sinister air, as if she had suddenly fallen into a tale told by H. P. Lovecraft. It is this very possibility that lurks behind Deleuze's comment that Hume's empiricism is "a kind of universe of science fiction: as in science fiction, the world seems fictional, strange, foreign, experienced by other creatures; but we get the feeling that this world is our own, and we are the creatures. …
- Published
- 2014
108. The association between timing of initiation of adjuvant therapy and the survival of early stage ovarian cancer patients - An analysis of NRG Oncology/Gynecologic Oncology Group trials
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James J. Java, Bradley J. Monk, Jeffrey G. Bell, John K. Chan, Thomas J. Herzog, Daniel S. Kapp, Katherine Fuh, and Robert C. Young
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Oncology ,Time Factors ,Survival ,Kaplan-Meier Estimate ,Carcinoma, Ovarian Epithelial ,Clear Cell ,Carboplatin ,0302 clinical medicine ,Cytology ,Neoplasms ,Ovarian Epithelial ,Antineoplastic Combined Chemotherapy Protocols ,Infusions, Parenteral ,Mucinous ,Neoplasms, Glandular and Epithelial ,Stage (cooking) ,Infusions, Intravenous ,Adjuvant ,Cancer ,Ovarian Neoplasms ,030219 obstetrics & reproductive medicine ,Obstetrics and Gynecology ,Glandular and Epithelial ,Cytoreduction Surgical Procedures ,Middle Aged ,Prognosis ,Ovarian Cancer ,Survival Rate ,Chemotherapy, Adjuvant ,030220 oncology & carcinogenesis ,Female ,Patient Safety ,Intravenous ,Carcinoma, Endometrioid ,6.4 Surgery ,Endometrioid ,medicine.medical_specialty ,Infusions ,Paclitaxel ,Oncology and Carcinogenesis ,Gynecologic oncology ,Surgical staging ,Adenocarcinoma ,Article ,Paediatrics and Reproductive Medicine ,03 medical and health sciences ,Cystic ,Rare Diseases ,Parenteral ,Clinical Research ,Internal medicine ,medicine ,Adjuvant therapy ,Overall survival ,Early stage ovarian cancer ,Humans ,Chemotherapy ,Oncology & Carcinogenesis ,Cyclophosphamide ,Neoplasm Staging ,Proportional Hazards Models ,Proportional hazards model ,business.industry ,and Serous ,Carcinoma ,Evaluation of treatments and therapeutic interventions ,medicine.disease ,Multivariate Analysis ,Cisplatin ,Ovarian cancer ,business ,Neoplasms, Cystic, Mucinous, and Serous ,Adenocarcinoma, Clear Cell - Abstract
ObjectivesTo determine the association between timing of adjuvant therapy initiation and survival of early stage ovarian cancer patients.MethodsData were obtained from women who underwent primary surgical staging followed by adjuvant therapy from two Gynecologic Oncology Group trials (protocols # 95 and 157). Kaplan-Meier estimates and Cox proportional hazards model adjusted for covariates were used for analyses.ResultsOf 497 stage I-II epithelial ovarian cancer patients, the median time between surgery and initiation of adjuvant therapy was 23days (25th-75th%: 12-33days). The time interval from surgery to initiation of adjuvant therapy was categorized into three groups: 4weeks. The corresponding 5-year recurrence-free survival rates were 72.8%, 73.9%, and 79.5% (p=0.62). The 5-year overall survival rates were 79.4%, 81.9%, and 82.8%, respectively (p=0.51; p=0.33 - global test). As compared to 4weeks. Age, stage, grade, and cytology were important prognostic factors.ConclusionsTiming of adjuvant therapy initiation was not associated with survival in early stage epithelial ovarian cancer patients.
- Published
- 2016
109. Bird Tissues from Museum Collections are Reliable for Assessing Avian Haemosporidian Diversity
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Nathan H. Rice, Erick A. García-Trejo, Jason D. Weckstein, Janice H. Dispoto, Alan Fecchio, Jeffrey A. Bell, Luis A. Sánchez-González, and Michael D. Collins
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0303 health sciences ,Leucocytozoon ,biology ,Cytochrome b ,Host (biology) ,030231 tropical medicine ,Bird collections ,Zoology ,biology.organism_classification ,medicine.disease ,Plasmodium ,030308 mycology & parasitology ,03 medical and health sciences ,0302 clinical medicine ,Avian malaria ,medicine ,Parasitology ,Evolutionary ecology ,Ornithology ,Ecology, Evolution, Behavior and Systematics - Abstract
Birds harbor a diverse group of haemosporidian parasites that reproduce and develop in the host blood cells, muscle tissue, and various organs, which can cause negative effects on the survival and reproduction of their avian hosts. Characterization of the diversity, distribution, host specificity, prevalence patterns, and phylogenetic relationships of these parasites is critical to the study of avian host-parasite ecology and evolution and for understanding and preventing epidemics in wild bird populations. Here, we tested whether muscle and liver samples collected as part of standard ornithological museum expeditions can be examined to study the diversity and distributions of haemosporidians in the same way as blood collected from individual birds that are typically banded and released. We used a standard molecular diagnostic screening method for mitochondrial DNA (cytochrome b) of the parasites and found that blood, muscle, and liver collected from the same host individual provide similar estimates of prevalence and diversity of haemosporidians from the genera Parahaemoproteus and Leucocytozoon. Although we found higher prevalence for the genus Plasmodium when we screened blood vs. liver and muscle samples, the estimates of the diversity of Plasmodium from different tissue types are not affected at the community level. Given these results, we conclude that for several reasons existing museum genetic resources collections are valuable data sources for the study of haemosporidians. First, ornithological museum collections around the world house tens of thousands of vouchered tissue samples collected from remote regions of the world. Second, the host specimens are vouchered and thus host identification and phenotype are permanently documented in databased archives with a diversity of associated ancillary data. Thus, not only can identifications be confirmed but also a diversity of morphological measurements and data can be measured and accessed for these host specimens in perpetuity.
- Published
- 2019
110. A New Species ofCrepidostomum(Digenea: Allocreadiidae) fromHiodon tergisusin Mississippi and Molecular Comparison with Three Congeners
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Stephen S. Curran, Jeffrey A. Bell, Robin M. Overstreet, and Vasyl V. Tkach
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Mitochondrial DNA ,biology ,Hiodon tergisus ,ved/biology ,Crepidostomum affine ,Molecular Sequence Data ,ved/biology.organism_classification_rank.species ,Fishes ,Zoology ,Anatomy ,Ribosomal RNA ,biology.organism_classification ,Crepidostomum auritum ,Digenea ,Intestines ,Fish Diseases ,Crepidostomum cornutum ,Mississippi ,Rivers ,Crepidostomum illinoiense ,DNA, Ribosomal Spacer ,Animals ,Parasitology ,Trematoda ,Ecology, Evolution, Behavior and Systematics - Abstract
A new species, Crepidostomum affine n. sp., is described from Hiodon tergisus in Mississippi, and morphological data are provided for Crepidostomum auritum from Aplodinotus grunniens in Mississippi and for Crepidostomum illinoiense from Hiodon alosoides in Minnesota. The new species is most similar morphologically to C. illinoiense, but has a shorter intertesticular space, measuring 0-74 μm (mean = 19.3 ± 23.1 SD in 73 specimens) compared with 0-229 μm (mean = 57.3 ± 56.7 SD in 34 specimens), and the distance between the ovary and the anterior testis is relatively shorter in the new species, representing 2.6-7.9% of overall body length compared with 4.1-12.4% in C. illinoiense. Fragments of nuclear ribosomal as well as mitochondrial DNA are compared among C. affine n. sp., C. illinoiense, C. auritum and Crepidostomum cornutum. Crepidostomum affine n. sp. and C. illinoiense are most similar, having between 19 and 20 variable bases (1.29-1.36%) in the amplified nuclear ribosomal RNA fragment comprising the complete ITS2 spacer and partial 28S gene, and between 35 and 39 variable bases (8.62-9.61%) in the amplified fragment of the COI region. Specimens of C. illinoiense from the Missouri River in North Dakota and Red Lake River in Minnesota differed by 1 base (0.07%) in the rRNA fragment and 4 bases (0.95%) in COI fragment. Crepidostomum cornutum and C. auritum also have 19 (1.29%) variable bases in the amplified ITS2 and partial 28S regions and 50 (12.32%) variable bases in the amplified COI region. Both C. cornutum and C. auritum demonstrated much greater levels of differences compared to C. affine n. sp. These results add to previously published data reporting species of fish digeneans that might be endemic to the Pearl and Pascagoula river basins in Mississippi.
- Published
- 2013
111. Allosteric Inhibition of the NS2B-NS3 Protease from Dengue Virus
- Author
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Woody Sherman, Jeanne A. Hardy, Sumana Ghosh, Jeffrey A. Bell, and Muslum Yildiz
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medicine.medical_treatment ,Allosteric regulation ,Viral Nonstructural Proteins ,Dengue virus ,medicine.disease_cause ,Antiviral Agents ,Biochemistry ,Article ,Protein Structure, Secondary ,Dengue fever ,Structure-Activity Relationship ,Enzyme activator ,chemistry.chemical_compound ,Allosteric Regulation ,Catalytic Domain ,medicine ,Protease Inhibitors ,Cysteine ,Cysteine metabolism ,NS3 ,Protease ,biology ,Serine Endopeptidases ,General Medicine ,Dengue Virus ,biology.organism_classification ,medicine.disease ,Virology ,Protein Structure, Tertiary ,Enzyme Activation ,Molecular Docking Simulation ,Kinetics ,Flavivirus ,chemistry ,Molecular Probes ,Mutation ,Molecular Medicine ,Allosteric Site ,Protein Binding - Abstract
Dengue virus is the flavivirus that causes dengue fever, dengue hemorrhagic disease, and dengue shock syndrome, which are currently increasing in incidence worldwide. Dengue virus protease (NS2B-NS3pro) is essential for dengue virus infection and is thus a target of therapeutic interest. To date, attention has focused on developing active-site inhibitors of NS2B-NS3pro. The flat and charged nature of the NS2B-NS3pro active site may contribute to difficulties in developing inhibitors and suggests that a strategy of identifying allosteric sites may be useful. We report an approach that allowed us to scan the NS2B-NS3pro surface by cysteine mutagenesis and use cysteine reactive probes to identify regions of the protein that are susceptible to allosteric inhibition. This method identified a new allosteric site utilizing a circumscribed panel of just eight cysteine variants and only five cysteine reactive probes. The allosterically sensitive site is centered at Ala125, between the 120s loop and the 150s loop. The crystal structures of WT and modified NS2B-NS3pro demonstrate that the 120s loop is flexible. Our work suggests that binding at this site prevents a conformational rearrangement of the NS2B region of the protein, which is required for activation. Preventing this movement locks the protein into the open, inactive conformation, suggesting that this site may be useful in the future development of therapeutic allosteric inhibitors.
- Published
- 2013
112. Nonlinear Dynamical Behavior in the Photodecomposition of N-Bromo-1,4-Benzoquinone-4-Imine
- Author
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Jichang Wang, James R. Green, and Jeffrey G. Bell
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1,4-Benzoquinone ,Autocatalysis ,chemistry.chemical_compound ,chemistry ,Inorganic chemistry ,Imine ,Sulfuric acid ,Physical and Theoretical Chemistry ,Carbon-13 NMR ,Photochemistry ,Kinetic energy ,Bromate ,Mass spectrometry - Abstract
Photodecomposition of N-bromo-1,4-benzoquinone-4-imine in water with and without the presence of oxidants was investigated, exhibiting nonlinear kinetic features such as autocatalytic excursion. An acidic environment was found to be essential for the observed photodecomposition. Mechanistic studies through NMR and mass spectrometry show the conversion of N-bromo-1,4-benzoquinone-4-imine into 1,4-benzoquinone. When bromate was introduced to the studied system, transient spontaneous oscillations were uncovered, forming a new photocontrolled chemical oscillator. The system's sensitivity to the intensity of the illumination is great as decreases halt the oscillations from occurring. Phase diagrams show that as the concentration of N-bromo-1,4-benzoquinone-4-imine is increased, broader concentration ranges of both bromate and sulfuric acid allow the system to exhibit spontaneous oscillations. Electrospray-TOF mass spectroscopy and (13)C NMR spectra suggest that 3,4,4-tribromo-2-hydroxycyclohexa-2,5-dienone is a major product in the bromate system.
- Published
- 2013
113. Altered resting hemodynamics in lower-extremity arteries of individuals with spinal cord injury
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Jeffrey W. Bell, Martin Bahls, Sean C. Newcomer, and David Chen
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Adult ,Male ,medicine.medical_specialty ,Adolescent ,medicine.medical_treatment ,Hemodynamics ,Femoral artery ,medicine.artery ,Internal medicine ,medicine ,Humans ,Popliteal Artery ,Spinal cord injury ,Tetraplegia ,Research Articles ,Spinal Cord Injuries ,Aged ,Ultrasonography ,Rehabilitation ,business.industry ,Ultrasound ,Middle Aged ,medicine.disease ,Popliteal artery ,Surgery ,Femoral Artery ,Cross-Sectional Studies ,Lower Extremity ,Cardiology ,Female ,Neurology (clinical) ,business ,Paraplegia - Abstract
To investigate lower-extremity arterial hemodynamics in individuals with spinal cord injury (SCI). We hypothesized that oscillatory shear index would be altered and resting mean shear would be higher in the lower-extremity arteries of SCI.Cross-sectional study of men and women with SCIs compared to able-bodied controls.Subjects included 105 ages 18-72 years with American Spinal Injury Association (ASIA) Impairment Scale grades A, B, or C and injury duration at least 5 years. Subjects were matched for age and cardiovascular disease risk factors with 156 able-bodied controls.Diameter and blood velocity were determined with subject at rest via ultrasound in superficial femoral, popliteal, brachial, and carotid arteries. Mean shear, antegrade shear, retrograde shear, and oscillatory shear index were calculated.Oscillatory shear index was lower in SCI compared to controls for superficial femoral (0.16 ± 0.10 vs. 0.26 ± 0.06, P0.01) and popliteal arteries (0.20 ± 0.11 vs. 0.26 ± 0.05, P0.01). Mean shear rate was higher in SCI compared to controls for superficial femoral (43.54 ± 28.0 vs. 20.48 ± 13.1/second, P0.01) and popliteal arteries (30.43 ± 28.1 vs. 11.68 ± 9.5/second, P0.01).The altered resting hemodynamics in SCI are consistent with an atheroprotective hemodynamic environment.
- Published
- 2013
114. Beyond the Analytic-Continental Divide : Pluralist Philosophy in the Twenty-First Century
- Author
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Jeffrey A. Bell, Andrew Cutrofello, Paul M. Livingston, Jeffrey A. Bell, Andrew Cutrofello, and Paul M. Livingston
- Subjects
- Continental philosophy, Analysis (Philosophy), Pluralism--21st century
- Abstract
This forward-thinking collection presents new work that looks beyond the division between the analytic and continental philosophical traditions—one that has long caused dissension, mutual distrust, and institutional barriers to the development of common concerns and problems. Rather than rehearsing the causes of the divide, contributors draw upon the problems, methods, and results of both traditions to show what post-divide philosophical work looks like in practice.Ranging from metaphysics and philosophy of mind to political philosophy and ethics, the papers gathered here bring into mutual dialogue a wide range of recent and contemporary thinkers, and confront leading problems common to both traditions, including methodology, ontology, meaning, truth, values, and personhood. Collectively, these essays show that it is already possible to foresee a future for philosophical thought and practice no longer determined neither as'analytic'nor as'continental,'but, instead, as a pluralistic synthesis of what is best in both traditions. The new work assembled here shows how the problems, projects, and ambitions of twentieth-century philosophy are already being taken up and productively transformed to produce new insights, questions, and methods for philosophy today.
- Published
- 2015
115. Philosophy at the Edge of Chaos : Gilles Deleuze and the Philosophy of Difference
- Author
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Jeffrey A. Bell and Jeffrey A. Bell
- Subjects
- Difference (Philosophy)
- Abstract
From the early 1960s until his death, French philosopher Gilles Deleuze (1925-1995) wrote many influential works on philosophy, literature, film, and fine art. One of Deleuze's main philosophical projects was a systematic inversion of the traditional relationship between identity and difference. This Deleuzian philosophy of difference is the subject of Jeffrey A. Bell's Philosophy at the Edge of Chaos. Bell argues that Deleuze's efforts to develop a philosophy of difference are best understood by exploring both Deleuze's claim to be a Spinozist, and Nietzsche's claim to have found in Spinoza an important precursor. Beginning with an analysis of these claims, Bell shows how Deleuze extends and transforms concepts at work in Spinoza and Nietzsche to produce a philosophy of difference that promotes and, in fact, exemplifies the notions of dynamic systems and complexity theory. With these concepts at work, Deleuze constructs a philosophical approach that avoids many of the difficulties that linger in other attempts to think about difference. Bell uses close readings of Plato, Aristotle, Spinoza, Nietzsche, Heidegger, Derrida, and Whitehead to illustrate how Deleuze's philosophy is successful in this regard and to demonstrate the importance of the historical tradition for Deleuze. Far from being a philosopher who turns his back on what is taken to be a mistaken metaphysical tradition, Bell argues that Deleuze is best understood as a thinker who endeavoured to continue the work of traditional metaphysics and philosophy.
- Published
- 2015
116. Outcome of the First wwPDB/CCDC/D3R Ligand Validation Workshop
- Author
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Oliver S. Smart, Paul Emsley, Cary B. Bauer, David A. Case, John L. Markley, Joseph Marcotrigiano, Jasmine Young, Atsushi Nakagawa, Seth F. Harris, Haruki Nakamura, Wolfram Tempel, Radka Svobodová, T. Krojer, Pamela A. Williams, Robert T. Nolte, Catherine E. Peishoff, Jorg Hendle, Chenghua Shao, Jeff Blaney, Dale E. Tronrud, Paul D. Adams, Randy J. Read, Marc C. Nicklaus, Kirk Clark, Helen M. Berman, Jeffrey A. Bell, Evan E Bolton, Suzanna C. Ward, Stephen K. Burley, Alan E. Mark, Garib N. Murshudov, Victoria A. Feher, Matthew T. Miller, John Spurlino, Sameer Velankar, Steven Sheriff, Tom Darden, Wladek Minor, Talapady N. Bhat, John D. Westbrook, Gerard J. Kleywegt, Terry R. Stouch, Huanwang Yang, Gérard Bricogne, Thomas C. Terwilliger, Anil K. Padyana, Zukang Feng, Colin R. Groom, Andrzej Joachimiak, David G. Brown, Anthony Nicholls, Gaetano T. Montelione, Thomas Holder, Kathleen Aertgeerts, Stephen M. Soisson, Gregory L. Warren, Susan Pieniazek, Read, Randy [0000-0001-8273-0047], and Apollo - University of Cambridge Repository
- Subjects
0301 basic medicine ,Models, Molecular ,Protein Conformation ,Complex formation ,Protein Data Bank (RCSB PDB) ,Biophysics ,Crystallographic data ,Guidelines as Topic ,010402 general chemistry ,Crystallography, X-Ray ,Ligands ,01 natural sciences ,Article ,03 medical and health sciences ,Structural bioinformatics ,Databases ,Extant taxon ,Structural Biology ,Models ,Information and Computing Sciences ,Databases, Protein ,Molecular Biology ,Data Curation ,Crystallography ,Ligand ,Chemistry ,Protein ,Molecular ,Proteins ,computer.file_format ,Collaboratory ,Biological Sciences ,Protein Data Bank ,Data science ,0104 chemical sciences ,030104 developmental biology ,Generic Health Relevance ,QD431 ,Chemical Sciences ,X-Ray ,computer - Abstract
Crystallographic studies of ligands bound to biological macromolecules (proteins and nucleic acids) represent\ud an important source of information concerning drug-target interactions, providing atomic level insights\ud into the physical chemistry of complex formation between macromolecules and ligands. Of the\ud more than 115,000 entries extant in the Protein Data Bank (PDB) archive, ~75% include at least one non-polymeric\ud ligand. Ligand geometrical and stereochemical quality, the suitability of ligand models for in silico drug\ud discovery and design, and the goodness-of-fit of ligand models to electron-density maps vary widely across\ud the archive. We describe the proceedings and conclusions from the first Worldwide PDB/Cambridge Crystallographic\ud Data Center/Drug Design Data Resource (wwPDB/CCDC/D3R) Ligand Validation Workshop\ud held at the Research Collaboratory for Structural Bioinformatics at Rutgers University on July 30–31, 2015.\ud Experts in protein crystallography from academe and industry came together with non-profit and for-profit\ud software providers for crystallography and with experts in computational chemistry and data archiving to\ud discuss and make recommendations on best practices, as framed by a series of questions central to structural\ud studies of macromolecule-ligand complexes. What data concerning bound ligands should be archived\ud in the PDB? How should the ligands be best represented? How should structural models of macromoleculeligand\ud complexes be validated? What supplementary information should accompany publications of structural\ud studies of biological macromolecules? Consensus recommendations on best practices developed in\ud response to each of these questions are provided, together with some details regarding implementation.\ud Important issues addressed but not resolved at the workshop are also enumerated.
- Published
- 2016
117. Deleuze and Guattari's What is Philosophy?
- Author
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Jeffrey A. Bell
- Published
- 2016
118. Significant reduction in errors associated with nonbonded contacts in protein crystal structures: automated all-atom refinement with PrimeX
- Author
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Kenneth L. Ho, Ramy Farid, and Jeffrey A. Bell
- Subjects
Models, Molecular ,clashes ,force fields ,Static Electricity ,Electrons ,Crystal structure ,restraints ,Energy minimization ,Crystallography, X-Ray ,Ligands ,molecular geometry ,symbols.namesake ,nonbonded contacts ,Structural Biology ,Atom ,Van der Waals radius ,refinement ,Computer Simulation ,Databases, Protein ,riding H atoms ,Hydrogen bond ,Chemistry ,Computational Biology ,Proteins ,Reproducibility of Results ,Hydrogen Bonding ,General Medicine ,model quality ,Research Papers ,electrostatics ,Molecular geometry ,Atomic radius ,Models, Chemical ,Drug Design ,hydrogen bonds ,symbols ,H atoms ,Atomic physics ,Protein crystallization ,Crystallization ,Algorithms ,Software ,van der Waals radii - Abstract
All-atom models derived from moderate-resolution protein crystal structures contain a high frequency of close nonbonded contacts, independent of the major refinement program used for structure determination. All-atom refinement with PrimeX corrects many of these problematic interactions, producing models that are better suited for use in computational chemistry and related applications., All-atom models are essential for many applications in molecular modeling and computational chemistry. Nonbonded atomic contacts much closer than the sum of the van der Waals radii of the two atoms (clashes) are commonly observed in such models derived from protein crystal structures. A set of 94 recently deposited protein structures in the resolution range 1.5–2.8 Å were analyzed for clashes by the addition of all H atoms to the models followed by optimization and energy minimization of the positions of just these H atoms. The results were compared with the same set of structures after automated all-atom refinement with PrimeX and with nonbonded contacts in protein crystal structures at a resolution equal to or better than 0.9 Å. The additional PrimeX refinement produced structures with reasonable summary geometric statistics and similar R free values to the original structures. The frequency of clashes at less than 0.8 times the sum of van der Waals radii was reduced over fourfold compared with that found in the original structures, to a level approaching that found in the ultrahigh-resolution structures. Moreover, severe clashes at less than or equal to 0.7 times the sum of atomic radii were reduced 15-fold. All-atom refinement with PrimeX produced improved crystal structure models with respect to nonbonded contacts and yielded changes in structural details that dramatically impacted on the interpretation of some protein–ligand interactions.
- Published
- 2012
119. A gynecologic oncology group phase II trial of two p53 peptide vaccine approaches: subcutaneous injection and intravenous pulsed dendritic cells in high recurrence risk ovarian cancer patients
- Author
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Samir N. Khleif, Mortada A. Shams, Albert B. DeLeo, Sarah Bernstein, V. E. Herrin, Malgorzata Czystowska, Judith K. Wolf, Seth M. Steinberg, Jay A. Berzofsky, Carmen Visus, William E. Gooding, Maria Merino, Jeffrey G. Bell, Theresa L. Whiteside, Ed Ashtar, Eva Wieckowski, Osama E. Rahma, and Marta Szajnik
- Subjects
Adult ,Oncology ,Cancer Research ,medicine.medical_specialty ,Injections, Subcutaneous ,T-Lymphocytes ,Immunology ,Kaplan-Meier Estimate ,Gynecologic oncology ,Cancer Vaccines ,Article ,Cohort Studies ,Subcutaneous injection ,Immune system ,Antigen ,Risk Factors ,Lymphopenia ,Internal medicine ,HLA-A2 Antigen ,medicine ,Humans ,Immunology and Allergy ,P53 Peptide Vaccine ,Fatigue ,Aged ,Ovarian Neoplasms ,business.industry ,Vaccination ,Granulocyte-Macrophage Colony-Stimulating Factor ,Dendritic Cells ,Middle Aged ,medicine.disease ,Combined Modality Therapy ,Treatment Outcome ,Injections, Intravenous ,Vaccines, Subunit ,Interleukin-2 ,Female ,Cancer vaccine ,Neoplasm Recurrence, Local ,Tumor Suppressor Protein p53 ,Ovarian cancer ,business - Abstract
Peptide antigens have been administered by different approaches as cancer vaccine therapy, including direct injection or pulsed onto dendritic cells; however, the optimal delivery method is still debatable. In this study, we describe the immune response elicited by two vaccine approaches using the wild-type (wt) p53 vaccine.Twenty-one HLA-A2.1 patients with stage III, IV, or recurrent ovarian cancer overexpressing the p53 protein with no evidence of disease were treated in two cohorts. Arm A received SC wt p53:264-272 peptide admixed with Montanide and GM-CSF. Arm B received wt p53:264-272 peptide-pulsed dendritic cells IV. Interleukin-2 (IL-2) was administered to both cohorts in alternative cycles.Nine of 13 patients (69%) in arm A and 5 of 6 patients (83%) in arm B developed an immunologic response as determined by ELISPOT and tetramer assays. The vaccine caused no serious systemic side effects. IL-2 administration resulted in grade 3 and 4 toxicities in both arms and directly induced the expansion of T regulatory cells. The median overall survival was 40.8 and 29.6 months for arm A and B, respectively; the median progression-free survival was 4.2 and. 8.7 months, respectively.We found that using either vaccination approach generates comparable specific immune responses against the p53 peptide with minimal toxicity. Accordingly, our findings suggest that the use of less demanding SC approach may be as effective. Furthermore, the use of low-dose SC IL-2 as an adjuvant might have interfered with the immune response. Therefore, it may not be needed in future trials.
- Published
- 2011
120. Nuclear P27 expression in benign, borderline (LMP) and invasive tumors of the ovary and its association with prognosis: A gynecologic oncology group study
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Jeffrey G. Bell, Michael J. Birrer, Kathleen M. Darcy, John H. Farley, Leia M. Smith, Mark F. Brady, and William McGuire
- Subjects
Oncology ,medicine.medical_specialty ,Cyclin E ,Ovary ,Gynecologic oncology ,Malignant transformation ,Internal medicine ,medicine ,Humans ,Neoplasm Invasiveness ,Clinical significance ,Stage (cooking) ,Aged ,Neoplasm Staging ,Cell Nucleus ,Ovarian Neoplasms ,business.industry ,Hazard ratio ,Obstetrics and Gynecology ,Middle Aged ,Prognosis ,Immunohistochemistry ,Cell Transformation, Neoplastic ,Cross-Sectional Studies ,medicine.anatomical_structure ,Female ,business ,Cyclin-Dependent Kinase Inhibitor p27 - Abstract
Nuclear p27 expression was examined in non-invasive and invasive ovarian tumors from a cross-sectional study, and clinical relevance of p27 was evaluated in the primary tumors from women participating in two randomized phase III treatment trials.An immunohistochemistry assay was used to detect p27 in formalin-fixed paraffin-embedded ovarian tumors from 3 distinct sources.Among the initial 91 ovarian tumors tested, low p27 expression (50% positive cells) was observed in 5.4% of non-invasive tumors versus 42.6% of invasive tumors (p0.001). In 145 ovarian cancers with high-risk early stage disease, 16.5% exhibited low p27 expression, and categorized p27 was not associated with age, race, or performance status. Low expression of p27 was common in poorly differentiated tumors (35.7%) compared to moderately (15.0%) and well (9.5%) differentiated tumors (p=0.024) and rare in clear cell carcinomas (2.4%) compared to other histologies (p=0.014). In the 139 cancers with advanced disease, 60% displayed low p27 expression, and categorized p27 expression was not associated with age, race, performance status, tumor grade, histologic subtype, measurable disease status or survival. Exploratory analyses revealed an association of cyclin E to p27 ratio1.0 with an increased risk of death (hazard ratio=1.53; p=0.017).Low p27 expression could be associated with malignant transformation of the ovarian epithelium and FIGO stage. A cyclin E to p27 ratio1.0 may be associated with shorter survival in these patients. Further study is required to confirm the trend for increased recurrences with low p27 expression in early stage disease.
- Published
- 2011
121. Between Realism and Anti-realism: Deleuze and the Spinozist Tradition in Philosophy
- Author
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Jeffrey A. Bell
- Subjects
Style (visual arts) ,Questions and answers ,Anti-realism ,French philosophy ,Philosophy ,Speculative realism ,Metaphysics ,Relation (history of concept) ,Realism ,Epistemology - Abstract
In 1967, after a talk Deleuze gave to the Society of French Philosophy, Ferdinand Alquié expressed concern during the question and answer session that perhaps Deleuze was relying too heavily upon science and not giving adequate attention to questions and problems that Alquié took to be distinctively philosophical. Deleuze responded by agreeing with Alquié; moreover, he argued that his primary interest was precisely in the metaphysics science needs rather than in the science philosophy needs. This metaphysics, Deleuze argues, is to be done ‘in the style of Whitehead’ rather than the style of Kant, and in developing this metaphysics Deleuze draws heavily on Spinoza. The present essay examines this Deleuzian-Spinozist metaphysics done in the style of Whitehead, the ‘metaphysics science needs’, drawing on the writings of David Hume and Bruno Latour in the process. This discussion will in turn enable us to situate Deleuze's metaphysics in relation to contemporary debates concerning speculative realism and correlationism, and especially Quentin Meillassoux's critique of the latter. Our conclusion will be that the kind of metaphysics Deleuze pursues is neither correlationist nor straightforwardly realist, but rather charts a course between realism and anti-realism.
- Published
- 2011
122. Robotic Radical Prostatectomy at a Teaching Community Hospital: Outcomes and Safety
- Author
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Julianna Padavano, Eric S. Ward, Wayne Poll, Lynn E.T. Shaffer, Kevin Banks, Jeffrey G. Bell, John Burgers, and Elizabeth A. Fannin
- Subjects
Adult ,Male ,medicine.medical_specialty ,medicine.medical_treatment ,education ,Hospitals, Community ,Community ,Prostate cancer ,medicine ,Operating time ,Scientific Papers ,Humans ,Hospitals, Teaching ,Perioperative Period ,Pathological ,Aged ,Retrospective Studies ,Prostatectomy ,Aged, 80 and over ,Urinary continence ,business.industry ,technology, industry, and agriculture ,Prostatic Neoplasms ,Perioperative ,Robotics ,Middle Aged ,Prostate-Specific Antigen ,medicine.disease ,Community hospital ,humanities ,Hospitals ,Surgery ,body regions ,Treatment Outcome ,Urinary Incontinence ,Quality of Life ,business ,Body mass index ,human activities - Abstract
Robotic prostatectomy was found to be a safe and successful option for prostate cancer treatment in a community teaching hospital., Objectives: This study describes the early experience of robotic prostatectomy exclusively at a teaching community hospital. Methods: This is a retrospective report of 153 consecutive patients on whom 4 physicians were the operating surgeon. Results: The average hospital stay was 1.5 days, the mean operative time was 175 minutes, and the estimated operative blood loss was
- Published
- 2011
123. Impact of chronic intermittent external compressions on forearm blood flow capacity in humans
- Author
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Bruno T. Roseguini, David Maurer, Brett D. Crist, M. H. Laughlin, Ryan D. Sheldon, Abigail Stroup, Sean C. Newcomer, and Jeffrey W. Bell
- Subjects
Adult ,Male ,medicine.medical_specialty ,Time Factors ,Brachial Artery ,Compressive Strength ,Physiology ,Hemodynamics ,Hyperemia ,Physical exercise ,Article ,Physical Phenomena ,Young Adult ,Forearm ,Physiology (medical) ,medicine.artery ,Hand strength ,Pressure ,medicine ,Humans ,Orthopedics and Sports Medicine ,Range of Motion, Articular ,Exercise physiology ,Brachial artery ,Exercise ,Hand Strength ,business.industry ,Public Health, Environmental and Occupational Health ,General Medicine ,Blood flow ,Biomechanical Phenomena ,Surgery ,medicine.anatomical_structure ,Regional Blood Flow ,Anesthesia ,Exercise Test ,medicine.symptom ,business ,Muscle Contraction ,Muscle contraction - Abstract
During dynamic exercise, the vasculature embedded within skeletal muscle intermittently collapses due to increased intramuscular pressure (IMP). The aim of this study was to ascertain whether oscillations in IMP during muscle contractions independently contribute to exercise training-induced increases in blood flow capacity (BFC). Based on IMP measurements during handgrip exercise, we attempted to mimic the action of repeated vascular compressions by using external inflatable cuffs. Thus, 24 healthy young male subjects underwent a 4-week program (5 days/week, 1 h/day) of application of external compressions of the non-dominant forearm, while the dominant limb served as an internal control. To evaluate the impact of compression pressures of different magnitudes, subjects were randomly assigned to one of three groups: 50, 100 and 150 mmHg of external compression. Prior to the intervention and after 2 and 4 weeks of treatment, we measured peak forearm blood flow (PBF) (Doppler ultrasound) and calculated peak vascular conductance (PVC) following 10 min of forearm ischemia. In the 50 and 100 mmHg groups, application of intermittent compressions did not alter PBF in either control or intervention forearms. In the 150 mmHg group, there was a trend (P = 0.04) for greater increases in PBF from baseline after 4 weeks in the intervention forearm compared to the control forearm (delta PBF: 4.2 ± 2.5 vs. -2.1 ± 2.0 (ml(100 ml)(-1) min(-1)), in the intervention and control forearms, respectively), but the changes in PVC were not significant (P = 0.1). These findings suggest that repeated oscillations in IMP contribute minimally to exercise-induced increase in forearm BFC in healthy young humans.
- Published
- 2010
124. No Effects of Skin Pressure Depth on Reaction Time
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Taylor L. Curtis, Jeffrey W. Bell, Landyn Van Overbeke, and Antonio Meikel
- Subjects
Physical Therapy, Sports Therapy and Rehabilitation ,Orthopedics and Sports Medicine - Published
- 2018
125. Survival after recurrence in early-stage high-risk epithelial ovarian cancer: A Gynecologic Oncology Group study
- Author
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Bradley J. Monk, Deanna Teoh, Chunqiao Tian, Daniel S. Kapp, Thomas J. Herzog, Jeffrey G. Bell, and John K. Chan
- Subjects
Adult ,Oncology ,medicine.medical_specialty ,Paclitaxel ,medicine.medical_treatment ,Gynecologic oncology ,Drug Administration Schedule ,Carboplatin ,Cohort Studies ,chemistry.chemical_compound ,Risk Factors ,Internal medicine ,Antineoplastic Combined Chemotherapy Protocols ,medicine ,Humans ,Stage (cooking) ,Survival rate ,Aged ,Neoplasm Staging ,Ovarian Neoplasms ,Chemotherapy ,Proportional hazards model ,business.industry ,Hazard ratio ,Obstetrics and Gynecology ,Middle Aged ,medicine.disease ,Survival Rate ,Treatment Outcome ,chemistry ,Chemotherapy, Adjuvant ,Female ,Neoplasm Recurrence, Local ,Ovarian cancer ,business - Abstract
Objective This study aimed to evaluate the clinical outcome of recurrent early-stage high-risk epithelial ovarian cancer patients. Methods Demographic and clinicopathological data were collected from women enrolled in GOG 157 who underwent surgical staging and had recurrent disease. Survival probability was estimated using Kaplan-Meier method, and hazard ratio of death was analyzed using Cox regression model. Results Of 74 women with recurrent early-stage high-risk ovarian cancer, the median age at recurrence was 63 years; 93% were White, 2.7% were Black, 2.7% were Asian, and 1.4% were Others. Fifty-eight percent had stage I, and the remainder had stage II disease. Clear cell, serous, endometrioid, mucinous, and other tumors consisted of 28.4%, 25.7%, 24.3%, 16.2%, and 5.4% of patients, respectively; in addition, 36.5% had ascites, 33.8% had positive cytology, and 43.2% had ruptured tumors. Fifty-eight percent underwent three cycles, and 42% had six cycles of adjuvant chemotherapy with paclitaxel and carboplatin. Recurrence was diagnosed clinically in 46% and radiographically in 54% of women. The median time from completion of primary chemotherapy to recurrence (treatment-free interval, TFI) was 21 months. Overall, median survival after recurrence was 24 months. Patients with longer (>24 months) TFI had a higher median survival after subsequent treatment at 35 months compared to only 10 months in those who recurred ≤24 months ( p =0.003). Conclusions Although patients with primary early-stage high-risk ovarian cancer have an overall favorable prognosis, survival after recurrence is poor and comparable to those with recurrent advanced-stage disease. Novel therapeutic modalities are warranted in these high-risk patients.
- Published
- 2010
126. Are prediction models for Lynch syndrome valid for probands with endometrial cancer?
- Author
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Jeffrey A. Bell, David E. Cohn, Heather Hampel, George S. Lewandowski, Gary C. Reid, Floor J. Backes, Larry J. Copeland, Katherine A. Backes, Luis Vaccarello, and Jeffrey M. Fowler
- Subjects
Adult ,Oncology ,Proband ,congenital, hereditary, and neonatal diseases and abnormalities ,Cancer Research ,medicine.medical_specialty ,Colorectal cancer ,MLH1 ,Risk Factors ,Internal medicine ,Genetics ,medicine ,Humans ,Family history ,neoplasms ,Genetics (clinical) ,Adaptor Proteins, Signal Transducing ,Probability ,Models, Statistical ,business.industry ,Endometrial cancer ,Nuclear Proteins ,nutritional and metabolic diseases ,Middle Aged ,medicine.disease ,Colorectal Neoplasms, Hereditary Nonpolyposis ,digestive system diseases ,Lynch syndrome ,Endometrial Neoplasms ,Surgery ,DNA-Binding Proteins ,MSH6 ,MutS Homolog 2 Protein ,MSH2 ,Female ,MutL Protein Homolog 1 ,business - Abstract
Currently, three prediction models are used to predict a patient's risk of having Lynch syndrome (LS). These models have been validated in probands with colorectal cancer (CRC), but not in probands presenting with endometrial cancer (EMC). Thus, the aim was to determine the performance of these prediction models in women with LS presenting with EMC. Probands with EMC and LS were identified. Personal and family history was entered into three prediction models, PREMM(1,2), MMRpro, and MMRpredict. Probabilities of mutations in the mismatch repair genes were recorded. Accurate prediction was defined as a model predicting at least a 5% chance of a proband carrying a mutation. From 562 patients prospectively enrolled in a clinical trial of patients with EMC, 13 (2.2%) were shown to have LS. Nine patients had a mutation in MSH6, three in MSH2, and one in MLH1. MMRpro predicted that 3 of 9 patients with an MSH6, 3 of 3 with an MSH2, and 1 of 1 patient with an MLH1 mutation could have LS. For MMRpredict, EMC coded as "proximal CRC" predicted 5 of 5, and as "distal CRC" three of five. PREMM(1,2) predicted that 4 of 4 with an MLH1 or MSH2 could have LS. Prediction of LS in probands presenting with EMC using current models for probands with CRC works reasonably well. Further studies are needed to develop models that include questions specific to patients with EMC with a greater age range, as well as placing increased emphasis on prediction of LS in probands with MSH6 mutations.
- Published
- 2009
127. Design of helix ends
- Author
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Jeffrey A. Bell and Swagata Dasgupta
- Subjects
chemistry.chemical_classification ,Stereochemistry ,Collagen helix ,Helix-turn-helix ,Biochemistry ,Amino acid ,chemistry.chemical_compound ,Crystallography ,Protein structure ,chemistry ,C cap ,Helix ,Alpha helix ,N cap - Abstract
The amino acid sequence and chemical interactions at the ends of 163 helices were surveyed so as better to understand amino acid preferences previously observed [Richardson, J.S. & Richardson, D.C. (1988) Science 240, 1648-1652]. Amino acid preferences differed from the previous survey in some significant details and in ways that might affect the choice of amino acids during the design of a protein helix. The following major conclusions about helix ends were deduced from additional patterns of amino acid occurrence and interactions that were observed. (1) A specific pair of hydrogen bonds is often observed between a glutamic acid (or glutamine) side chain at the N3 position and the N-cap amide hydrogen, and between the N-cap side chain (often threonine) and the N3 amide hydrogen. This reciprocal interaction may be an important means of stabilizing the N-terminal end of a helix. (2) Negatively charged amino acids (aspartic acid and glutamic acid) at the N-terminal end of helices may be more important in stabilizing protein helices than positively charged residues (chiefly lysine) at the C-terminal end. (3) The identity of the residue at the N-cap position is correlated with the backbone conformation at that position. (4) Aspartic acid (or asparagine) at the N2 or N3 position may adopt a conformation that suggests a hydrogen-bonding interaction with the end of the helix, especially when the N-cap side chain does not form a hydrogen bond with the end of the helix.
- Published
- 2009
128. Associations between p53 overexpression and multiple measures of clinical outcome in high-risk, early stage or suboptimally-resected, advanced stage epithelial ovarian cancers
- Author
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John H. Farley, William E. Brady, Kathleen M. Darcy, Jeffrey G. Bell, Denver T. Hendricks, John W. McBroom, Tomas Bonome, Robert C. Young, William McGuire, and R. Ilona Linnoila
- Subjects
Oncology ,medicine.medical_specialty ,endocrine system diseases ,Cyclophosphamide ,business.industry ,Obstetrics and Gynecology ,Gynecologic oncology ,medicine.disease ,female genital diseases and pregnancy complications ,Carboplatin ,law.invention ,Clinical trial ,chemistry.chemical_compound ,chemistry ,Randomized controlled trial ,Paclitaxel ,law ,Internal medicine ,medicine ,Stage (cooking) ,Ovarian cancer ,business ,medicine.drug - Abstract
Objective The Gynecologic Oncology Group (GOG) performed a detailed analysis of p53 overexpression in previously-untreated women with invasive early or advanced stage epithelial ovarian cancer (EOC).
- Published
- 2008
129. History Undone: Towards a Deleuzo-Guattarian Philosophy of History
- Author
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Jeffrey A. Bell
- Subjects
Deleuze and Guattari ,Philosophy of history ,Aesthetics ,Philosophy ,Experimental work ,Event (philosophy) ,Order (virtue) ,Epistemology - Abstract
For those familiar with the work of Deleuze, and Deleuze and Guattari, it might at first seem unwise to pursue a Deleuze and Guattarian philosophy of history. After all, is it not Deleuze who, in an interview with Antonio Negri, argues that ‘What history grasps in an event is the way it’s actualized in particular circumstances; the event's becoming is beyond the scope of history'? (Deleuze 1995 : 170). And more damningly, Deleuze adds, ‘History isn’t experimental, it's just the set of more or less negative preconditions that make it possible to experiment with something beyond history' (Deleuze 1995 : 170). History, in short, is a starting point for experimental work, but it is precisely history ‘that one leaves behind in order to “become,” that is, to create something new’ (1995: 171). Similarly in A Thousand Plateaus, Deleuze and Guattari argue that ‘History is made by those who oppose history (not by those who insert themselves into it, or even reshape it)’ (Deleuze and Guattari 1987 : 295). In the very first line of his book, Lampert recognizes the possible conclusion these citations might lead one to, namely, ‘Deleuze and Guattari’s philosophy of becoming seems at times opposed to the very idea of historical succession' (1); and yet, as Lampert adeptly demonstrates, it would be a mistake to conclude that opposing history to ‘create something new’, ‘something beyond history’, necessarily entails being hostile to history, to the ‘idea of historical succession’, and thus to a philosophy of history.
- Published
- 2008
130. Passage of Ingested Mansonella ozzardi (Spirurida: Onchocercidae) Microfilariae Through the Midgut of Aedes aegypti (Diptera: Culicidae)
- Author
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Michael J. Turell, Dave D. Chadee, Jeffrey A. Bell, and Jefferson A. Vaughan
- Subjects
General Veterinary ,biology ,Ceratopogonidae ,fungi ,Midgut ,Aedes aegypti ,Dengue virus ,medicine.disease ,Onchocercidae ,biology.organism_classification ,medicine.disease_cause ,Microfilaria ,Virology ,Dengue fever ,Infectious Diseases ,Insect Science ,parasitic diseases ,medicine ,Parasitology ,Mansonella ozzardi - Abstract
When virus and microfilariae are ingested concurrently by a mosquito, microfilariae (mf) may penetrate the mosquito midgut and introduce virus directly into the mosquito hemocoel, allowing mosquitoes to become infectious much sooner than normal and enhancing transmission of viruses by mosquitoes. Mansonella ozzardi (Manson) is a benign filarial nematode parasite of humans in Latin America and is transmitted by black flies (Diptera: Simuliidae) and biting midges (Diptera: Ceratopogonidae). Because M. ozzardi and dengue are sympatric, we wanted to know whether M. ozzardi mf had the ability to penetrate the midgut of Aedes aegypti (L.) (Diptera: Culicidae) and thus play a potential role in the enhancement of dengue transmission. To test this, the F1 progeny from locally collected Ae. aegypti were fed on M. ozzardi-infected human males in an endemic village in northern Trinidad. Mosquitoes were dissected at various times after feeding and examined for mf in the midguts and thoraces. Microfilariae penetrated the midguts of 43% of 63 mosquitoes that ingested mf. Overall, 11% of mf penetrated the midgut by 17 h after being ingested. The intensity of midgut penetration was positively correlated to the numbers of mf ingested. Because midgut penetration is a key requirement for mf enhancement to occur, the potential exists that M. ozzardi could be involved in the enhancement of dengue virus transmission.
- Published
- 2007
131. Beyond the Analytic-Continental Divide
- Author
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Andrew Cutrofello, Jeffrey A. Bell, and Paul M. Livingston
- Subjects
Phenomenology (philosophy) ,Contemporary philosophy ,Meaning (philosophy of language) ,Analytic philosophy ,Philosophy ,Intentionality ,Metaphysics ,Criticism ,Relativism ,Epistemology - Abstract
1. Introduction: Contemporary Philosophy as Synthetic Philosophy Jeffrey A. Bell, Andrew Cutrofello, and Paul M. Livingston Part I: Methodologies 2. The Emergence of the Concept of the Analytic Tradition as a Form of Philosophical Self-Consciousness James Conant 3. Philosophy as Articulation: Austin and Deleuze on Conceptual Analysis Richard Eldridge and Tamsin Lorraine 4. Conceptual Genealogy for Analytic Philosophy Catarina Dutilh Novaes Part II: Truth and Meaning 5. Truth and Epoche: The Semantic Conception of Truth in Phenomenology David Woodruff Smith 6. From Difference-Maker to Truthmaker (and Back) Jeffrey A. Bell 7. Reasons, Epistemic Truth, and History: Foucault's Criticism of Putnam's Anti-Realism Lee Braver 8. Metaphor without Meanings: Derrida and Davidson as Complementary Samuel C. Wheeler III Part III: Metaphysics and Ontology 9. Why is Time Different from Space? John McCumber 10. Wittgenstein Reads Heidegger, Heidegger Reads Wittgenstein: Thinking Language Bounding World Paul M. Livingston 11. The Answer to the Question of Being Graham Priest Part IV: Values, Personhood, and Agency 12. Relativism and Recognition Carol Rovane 13. Revolutionary Actions and Events Andrew Cutrofello 14. Varieties of Shared Intentionality: Tomasello and Classical Phenomenology Dan Zahavi and Glenda Satne
- Published
- 2015
132. From Difference-Maker to Truthmaker (and Back)
- Author
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Jeffrey A. Bell
- Subjects
Phrase ,Nothing ,Philosophy ,Truthmaker ,Object (philosophy) ,Epistemology - Abstract
At the beginning of Sein und Zeit, Martin Heidegger famously asked the question of being: "what is it to be". Heidegger refers to an object, a being. If "is" referred to a being then the italicized phrase would simply be a list of two objects: Heidegger and being. Heidegger was well aware of the problem, and he wrestled with various ways to avoid it. Thus, he tried the technique of writing under erasure. Heidegger was right in his conclusion that one cannot say anything about the being of an object, and in case one thinks this is some peculiarity of Heideggerian philosophy, it is worth noting that the very same situation occurs in some paradoxes of self-reference. Heidegger was right in insisting that the being of a being is not itself an object/being, and in concluding that one could therefore say nothing about it. The answer to the question of being requires us to talk of the ineffable.
- Published
- 2015
133. Charting the Road of Inquiry: Deleuze's Humean Pragmatics and the Challenge of Badiou
- Author
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Jeffrey A. Bell
- Subjects
Deleuze and Guattari ,Philosophy ,media_common.quotation_subject ,Criticism ,Spinozism ,Pragmatics ,Experimental philosophy ,Creativity ,Epistemology ,media_common - Abstract
This essay responds to Badiou's charge that Deleuze fails to set forth a philosophy that is “beyond Gategorical oppositions.” It is argued that this criticism of Deleuze is founded upon a misreading of the Deleuzean distinction between the virtual and the actual, a reading that carries forward Badiou's misreading of Spinoza and, hence, of Deleuze's Spinozism. With this corrected, we show how the virtual-actual distinction operates within the experimental philosophy, or pragmatics, that Deleuze, and later Deleuze and Guattari, sets forth. It is this pragmatics that is precisely the philosophy of difference that is beyond categorical oppositions. Through a comparison of Deleuzean pragmatics with the work of Hume and Peirce, we are able to respond to Badiou's further criticism that Deleuze's philosophy fails to understand the conditions for creativity in thought and culture. This criticism is itself resolved once one corrects for Badiou's misreading of Deleuze's virtual-actual distinction.
- Published
- 2006
134. West Nile Virus in Host-Seeking Mosquitoes within a Residential Neighborhood in Grand Forks, North Dakota
- Author
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Nathan J. Mickelson, Jefferson A. Vaughan, and Jeffrey A. Bell
- Subjects
West Nile virus ,Ochlerotatus ,viruses ,Zoology ,Culex tarsalis ,Biology ,medicine.disease_cause ,Risk Assessment ,Microbiology ,Environmental temperature ,Aedes ,Residence Characteristics ,Virology ,parasitic diseases ,Prevalence ,medicine ,Animals ,Humans ,Relative species abundance ,Aedes vexans ,Analysis of Variance ,Reverse Transcriptase Polymerase Chain Reaction ,Sequence Analysis, RNA ,Ecology ,fungi ,Temperature ,Genetic Variation ,virus diseases ,Ochlerotatus dorsalis ,biology.organism_classification ,Brood ,Insect Vectors ,nervous system diseases ,Culex ,Infectious Diseases ,North Dakota ,Host seeking ,Capsid Proteins ,Female ,Seasons ,West Nile Fever - Abstract
West Nile virus (WNV) was first recovered in North Dakota near the city of Grand Forks in June 2002. During 2002, 2003, and 2004, we collected mosquitoes from Grand Forks using Mosquito Magnet traps and tested them for WNV. The seasonal abundance, species composition, and reproductive status of female mosquitoes were correlated with local environmental temperature and state surveillance data on WNV to determine the factors affecting local transmission of WNV. Over 90% of the mosquitoes collected were Aedes vexans, Ochlerotatus dorsalis, and Culex tarsalis, but WNV was detected only in Cx. tarsalis. Average summertime temperatures and relative abundance of mosquitoes were highest in 2002 but no WNV-positive mosquitoes were detected until the following summer. In 2003, nulliparous Cx. tarsalis appeared in mid-June (first summer brood), and parous Cx. tarsalis appeared in mid-July. The first WNV-positive pool occurred 21 July, and minimum daily infections rates increased thereafter until 27 August. The minimum infection rate (MIR) for Cx. tarsalis during the season was 5.7 infected mosquitoes per 1,000 tested, with the highest infection rates occurring at the end of the season as Cx. tarsalis populations started to decline. Mid-to-late August was identified as the period of highest risk for being bitten by a WNV-infected mosquito in Grand Forks during 2003. In 2004, viral activity in Grand Forks was low, due to very cool temperatures throughout the summer. To examine the genetic diversity of the 2003 WNV isolates from Grand Forks, we sequenced a 366-nucleotide region of the capsid and premembrane gene. Thirteen (46%) of the 28 WNV isolates contained at least one nucleotide substitution when compared to the homologous region of the progenitor WN NY-99 strain, and seven of these 13 substitutions coded for amino acid changes. Thus, WNV is established in North Dakota, it appears to be evolving and it is vectored primarily by Cx. tarsalis.
- Published
- 2005
135. Genetic variation and phylogeographic analyses of two species of Carpobrotus and their hybrids in California
- Author
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V. Vaughan Symonds, Kelly G. Gallagher, Jeffrey R. Bell, and Kristina A. Schierenbeck
- Subjects
education.field_of_study ,biology ,Population ,Carpobrotus chilensis ,Carpobrotus ,biology.organism_classification ,Gene flow ,Carpobrotus edulis ,Evolutionary biology ,Botany ,Genetic variation ,Genetics ,Genetic variability ,Restriction fragment length polymorphism ,education ,Ecology, Evolution, Behavior and Systematics - Abstract
Despite the commonality and study of hybridization in plants, there are few studies between invasive and noninvasive species that examine the genetic variability and gene flow of cytoplasmic DNA. We describe the phylogeographical structure of chloroplast DNA (cpDNA) variation within and among several interspecific populations of the putative native, Carpobrotus chilensis and the introduced, Carpobrotus edulis (Aizoaceae). These species co-occur throughout much of coastal California and form several 'geographical hybrid populations'. Two hundred and thirty-seven individuals were analysed for variation in an approximate 7.0 kb region of the chloroplast genome using PCR-RFLP (polymerase chain reaction - restriction fragment length polymorphism) data. Phylogenetic analyses and cpDNA population differentiation were conducted for all morphotypes. Historic geographical dispersion and the coefficient of ancestry of the haplotypes were determined using nested clade analyses. Two haplotypic groupings (I and II) were represented in C. chilensis and C. edulis, respectively. The variation in cpDNA data is in agreement with the previously reported allozyme and morphological data; this supports relatively limited variation and high population differentiation among C. chilensis and hybrids and more wide-ranging variation in C. edulis and C. edulis populations backcrossed with C. chilensis. C. chilensis disproportionately contributes to the creation of hybrids with the direction of gene flow from C. chilensis into C. edulis. The cpDNA data support C. chilensis as the maternal contributor to the hybrid populations.
- Published
- 2005
136. Prognostic Significance of p53 Mutation and p53 Overexpression in Advanced Epithelial Ovarian Cancer: A Gynecologic Oncology Group Study
- Author
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Jorge Leon, Jeffrey G. Bell, Kathleen M. Darcy, Andrew Berchuck, Roger L. Priore, Hasnah Hamdan, and Laura J. Havrilesky
- Subjects
Oncology ,Cancer Research ,medicine.medical_specialty ,Pathology ,Tumor suppressor gene ,DNA Mutational Analysis ,Gynecologic oncology ,medicine.disease_cause ,Disease-Free Survival ,Exon ,Internal medicine ,Carcinoma ,medicine ,Humans ,Neoplasms, Glandular and Epithelial ,Survival analysis ,Ovarian Neoplasms ,Mutation ,business.industry ,Middle Aged ,Genes, p53 ,Prognosis ,medicine.disease ,Immunohistochemistry ,Survival Analysis ,genomic DNA ,Treatment Outcome ,Female ,Tumor Suppressor Protein p53 ,business - Abstract
Purpose: The prognostic significance of p53 mutations and overexpression in advanced epithelial ovarian cancers was examined in primary tumors from 125 patients participating in a Gynecologic Oncology Group randomized phase III treatment protocol. Patients and Methods: Mutational analysis of p53 was performed in RNA or genomic DNA extracted from frozen tumor. An immunohistochemistry assay was used to detect p53 overexpression in fixed tumor. Results: There were 81 patients (74%) with a single mutation, three patients (3%) with two mutations, and 25 patients (23%) lacking a mutation in exons 2 to 11 of p53. Although most mutations occurred within exons 5 to 8, mutations outside this region were observed in 11% of patients. A mutation in exons 2 to 11 of p53 was associated with a short-term improvement in overall survival and progression-free survival. Adjusted Cox modeling demonstrated a 70% reduction in risk of death (P = .014) and a 60% reduction in risk of disease progression (P = .014) for women with such mutations. However, these striking risk reductions increased over time (P < .02) and eventually disappeared with longer follow-up. Overexpression of p53 was observed in 55 patients (100%) with only missense mutation(s), seven patients (32%) with truncation mutations, and eight patients (40%) lacking a mutation in exons 2 to 11. Overexpression of p53 was associated with tumor grade but not with patient outcome. Conclusion: Alterations in p53 are a common event in advanced epithelial ovarian cancer. A mutation in p53, but not overexpression of p53, is associated with a short-term survival benefit. Additional studies are required to define the roles that p53 plays in regulating therapeutic responsiveness and patient outcome.
- Published
- 2003
137. Cisplatin as second-line therapy in ovarian carcinoma treated initially with single-agent paclitaxel: a Gynecologic Oncology Group study
- Author
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Jeffrey G. Bell, George J. Olt, John A. Blessing, J. Tate Thigpen, and Samuel S. Lentz
- Subjects
Adult ,medicine.medical_specialty ,Paclitaxel ,Cyclophosphamide ,medicine.medical_treatment ,Antineoplastic Agents ,Gynecologic oncology ,Neutropenia ,Gastroenterology ,Disease-Free Survival ,Drug Administration Schedule ,chemistry.chemical_compound ,Internal medicine ,medicine ,Carcinoma ,Humans ,Aged ,Aged, 80 and over ,Ovarian Neoplasms ,Cisplatin ,Chemotherapy ,business.industry ,Obstetrics and Gynecology ,Middle Aged ,medicine.disease ,Surgery ,Oncology ,chemistry ,Drug Resistance, Neoplasm ,Disease Progression ,Female ,Neoplasm Recurrence, Local ,business ,Progressive disease ,medicine.drug - Abstract
Objectives The platinum compounds are the most active agents in the treatment of ovarian carcinoma. Phase II trials demonstrated the activity of paclitaxel in patients with disease clinically resistant to platinum-based front-line therapy, and phase III studies confirmed that a combination of paclitaxel plus a platinum was superior to cyclophosphamide plus a platinum. This study evaluated the activity of platinum in patients with bulky advanced disease treated with single-agent paclitaxel as front-line therapy on a Gynecologic Oncology Group protocol. Those patients who had persistent (stable) or progressive disease while receiving paclitaxel, or a recurrence of disease within 6 months of completing six cycles of paclitaxel therapy, received single-agent cisplatin. Methods Thirty-nine eligible patients with ovarian carcinoma persistent, progressive, or recurrent after initial treatment with paclitaxel 200 mg/m 2 over 24 h every 3 weeks received cisplatin 100 mg/m 2 every 3 weeks until disease progression or unacceptable toxicity. Results Among 37 patients evaluable for response, 8 complete (22%) and 13 partial (35%) responses resulted. Twelve (32%) patients exhibited stable disease, while 4 (11%) had increasing disease. Median progression-free survival was 11.0 months. Median survival was 15.0 months. All but two patients were clinically resistant to paclitaxel (progression during or within 6 months after completion of paclitaxel). Grade 2 or worse adverse effects among 39 patients evaluable for toxicity included neutropenia (23), thrombocytopenia (3), anemia (10), nausea and vomiting (23), azotemia (7), neurotoxicity (9), fever (2), and tinnitus (1). Conclusion These data provide evidence that cisplatin is active as second-line therapy in patients clinically resistant to paclitaxel. The overall response rate is high (57%) with excellent progression-free and overall survival in the second-line setting.
- Published
- 2003
138. Crystine: fibrous biomolecular material from protein crystals cross-linked in a specific geometry
- Author
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Jeffrey A. Bell, W.A. Samsonoff, T.A. Przybycien, U. Srinivasan, and Ganesh H. Iyer
- Subjects
biology ,Chemistry ,Bioengineering ,Crystallography, X-Ray ,Biochemistry ,Maltose-Binding Proteins ,Buffer (optical fiber) ,law.invention ,Crystal ,Microscopy, Electron ,Structure-Activity Relationship ,Maltose-binding protein ,Crystallography ,law ,Transmission electron microscopy ,Mutation ,Microscopy ,biology.protein ,Crystallization ,Carrier Proteins ,Protein crystallization ,Molecular Biology ,Dissolution ,Biotechnology - Abstract
Cysteine substitutions were engineered on the surface of maltose binding protein to produce crystine fibers, linear polymers of folded protein formed within a crystal. Disulfide bond formation between adjacent protein molecules within the lattice was monitored by X-ray crystallography. The cross-linked crystals were resistant to dissolution in water or neutral buffer solutions, even though the cross-linking was one-dimensional. However, crystine fibers were observed by transmission electron microscopy to dissociate from the crystals in acidic solutions. Some fibers remained associated as two-dimensional bundles or sheets, with a repeat unit along the fibers consistent with the packing of the individual protein molecules in the crystal. Neutralization of the acidic solutions caused the fibers to re-associate as a solid. Crystine threads were drawn out of this solution. In scanning electron microscopy images, many individual fibers could be seen unwinding from the ends of some threads. Crystine fibers are a new type of biomolecular material with potential applications wherever the use of proteins in a fibrous form is desirable, for example, the incorporation of enzymes into cloth or filtration material.
- Published
- 2002
139. Selection of obstetrics and gynecology residents on the basis of medical school performance
- Author
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Jeffrey G. Bell, Lynn E.T. Shaffer, and Ioanna Kanellitsas
- Subjects
Gerontology ,medicine.medical_specialty ,education ,Standardized test ,Cognition ,Obstetrics and gynaecology ,Humans ,Medicine ,Statistical analysis ,Overall performance ,Personnel Selection ,Schools, Medical ,business.industry ,Medical school ,Clinical performance ,Internship and Residency ,Obstetrics and Gynecology ,Licensure, Medical ,United States Medical Licensing Examination ,Obstetrics ,Gynecology ,Family medicine ,Educational Status ,Regression Analysis ,Clinical Competence ,business ,Forecasting - Abstract
Objective: The purpose of this study was to determine whether United States Medical Licensing Examination scores during medical school predict resident-in-training examination scores and whether other criteria of medical student performance correlate with the faculty's subjective evaluation of resident performance. Study Design: United States Medical Licensing Examination step I and II scores for 24 residents were compared to their scores on in-training examinations. Faculty evaluated 20 graduated residents by rating both their cognitive and noncognitive clinical performance. Scores from these evaluations were compared with several criteria of their medical school performance. Statistical analysis for all comparisons was linear regression. Results: United States Medical Licensing Examination scores positively correlated with in-training examination scores. United States Medical Licensing Examination scores, honor grades in student clinical rotations, and student interview scores did not correlate with the faculty evaluation of resident performance. Conclusion: Standardized tests of medical student cognitive function predict the resident's performance on standardized tests. Selection criteria that are based on other medical school achievements do not necessarily correlate with overall performance as residents in obstetrics and gynecology. (Am J Obstet Gynecol 2002;186:1091-4.)
- Published
- 2002
140. Early detection of ovarian cancer
- Author
-
Jeffrey G. Bell
- Subjects
Vaginal Smears ,Oncology ,Cancer Research ,medicine.medical_specialty ,business.industry ,MEDLINE ,Uterine Cervical Neoplasms ,Early detection ,Papanicolaou Test ,Disease ,medicine.disease ,Early Diagnosis ,Internal medicine ,medicine ,Humans ,Female ,business ,Ovarian cancer - Published
- 2011
141. Scientism and the Modern World
- Author
-
Jeffrey A. Bell
- Subjects
Scientism ,Philosophy ,Environmental ethics - Published
- 2014
142. Ionic strength and intermolecular contacts in protein crystals
- Author
-
Swagata Dasgupta, Jeffrey A. Bell, and Ganesh H. Iyer
- Subjects
chemistry.chemical_classification ,Chemistry ,Intermolecular force ,Ionic bonding ,Condensed Matter Physics ,Amino acid ,law.invention ,Inorganic Chemistry ,Crystal ,Crystallography ,Ion binding ,Ionic strength ,law ,Materials Chemistry ,Crystallization ,Protein crystallization - Abstract
The ionic strengths of crystallization solutions for 206 proteins were observed to form a bimodal distribution. The data was divided into two sets at an ionic strength of 4.4 M, and knowledge-based potentials were calculated to determine contact preferences at intermolecular crystal interfaces. Consistent with previous observations over all ionic strengths, intermolecular crystal contacts tend to exclude nonpolar amino acids; lysine is the least favored polar amino acid at crystal contacts; and arginine and glutamine are the two most favored amino acid at crystal contacts. However, some aspects of intermolecular contact preferences within protein crystals are significantly dependent on ionic strength. Arginine is the most favored residue at low ionic strength, but it takes second place to glutamine at high ionic strength. Other major ionic strength-dependent differences in protein crystal contacts can be explained by the binding of cations or anions. While others have shown the importance of ion binding experimentally in selected protein crystals, these statistical results indicate that intermolecular interface formation must involve ion-mediated contacts in a large number of protein crystals.
- Published
- 2000
143. X-ray crystal structures of a severely desiccated protein
- Author
-
Jeffrey A. Bell
- Subjects
biology ,Protein Conformation ,Chemistry ,Static Electricity ,Intermolecular force ,Resolution (electron density) ,Ribonuclease, Pancreatic ,Dielectric ,Crystal structure ,Crystallography, X-Ray ,Bovine pancreatic ribonuclease ,Biochemistry ,Crystallography ,Protein structure ,biology.protein ,Animals ,Cattle ,Denaturation (biochemistry) ,Protein crystallization ,Pancreas ,Molecular Biology ,Research Article - Abstract
Unlike most protein crystals, form IX of bovine pancreatic ribonuclease A diffracts well when severely dehydrated. Crystal structures have been solved after 2.5 and 4 days of desiccation with CaSO4, at 1.9 and 2.0 A resolution, respectively. The two desiccated structures are very similar. An RMS displacement of 1.6 A is observed for main-chain atoms in each structure when compared to the hydrated crystal structure with some large rearrangements observed in loop regions. The structural changes are the result of intermolecular contacts formed by strong electrostatic interactions in the absence of a high dielectric medium. The electron density is very diffuse for some surface loops, consistent with a very disordered structure. This disorder is related to the conformational changes. These results help explain conformational changes during the lyophilization of protein and the associated phenomena of denaturation and molecular memory.
- Published
- 1999
144. West Nile Virus Epizootiology, Central Red River Valley, North Dakota and Minnesota, 2002–2005
- Author
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Jefferson A. Vaughan, Jeffrey A. Bell, Christina M. Brewer, Gabriel W. Garman, and Nathan J. Mickelson
- Subjects
Microbiology (medical) ,Epidemiology ,Culex ,West Nile virus ,Minnesota ,animal diseases ,viruses ,030231 tropical medicine ,education ,lcsh:Medicine ,Culex tarsalis ,Antibodies, Viral ,medicine.disease_cause ,lcsh:Infectious and parasitic diseases ,03 medical and health sciences ,0302 clinical medicine ,Zoonoses ,medicine ,Animals ,lcsh:RC109-216 ,Passeriformes ,030212 general & internal medicine ,passerine birds ,Bird Diseases ,River valley ,biology ,seroprevalence ,Ecology ,lcsh:R ,Dispatch ,virus diseases ,Epizootiology ,biology.organism_classification ,epitope-blocking enzyme-linked immunosorbent assay (ELISA) ,Insect Vectors ,3. Good health ,nervous system diseases ,Infectious Diseases ,North Dakota ,West Nile Fever - Abstract
West Nile virus (WNV) epizootiology was monitored from 2002 through 2005 in the area surrounding Grand Forks, North Dakota. Mosquitoes were tested for infection, and birds were surveyed for antibodies. In 2003, WNV was epidemic; in 2004, cool temperatures precluded WNV amplification; and in 2005, immunity in passerines decreased, but did not preclude, WNV amplification.
- Published
- 2006
145. Relationship of Nonstaging Pathological Risk Factors to Lymph Node Metastasis and Recurrence in Clinical Stage I Endometrial Carcinoma
- Author
-
Jeffrey Judis, Gary C. Reid, Jeffrey G. Bell, Mark Brownell, and Angela Minnick
- Subjects
medicine.medical_specialty ,Pathology ,Matched-Pair Analysis ,Receptors, Cell Surface ,Metastasis ,Risk Factors ,medicine ,Humans ,Neoplasm Invasiveness ,Pathological ,Lymph node ,Aged ,Neoplasm Staging ,Ploidies ,Oncogene ,business.industry ,Obstetrics and Gynecology ,DNA, Neoplasm ,Genes, erbB-2 ,Middle Aged ,Genes, p53 ,medicine.disease ,Immunohistochemistry ,Endometrial Neoplasms ,Genes, bcl-2 ,medicine.anatomical_structure ,Oncology ,Hormone receptor ,Case-Control Studies ,Lymphatic Metastasis ,Blood Vessels ,Female ,Histopathology ,Lymph ,Neoplasm Recurrence, Local ,business - Abstract
Objective. To determine if DNA ploidy, hormone receptors, vascular space invasion (VSI), perivascular lymphocytes (PVL), and the oncogenes HER-2/neu, p53, and bcl-2 are independent prognostic indicators for lymph node metastasis and cancer recurrence in clinical stage I endometrial carcinoma. Methods. Among 349 patients with clinical stage I endometrial cancer 31 patients either had lymph node metastases when surgically staged or developed recurrent cancer. Using a case–control matched-pair technique, controls were selected for each of 24 cases by matching for age, histological grade, depth of myometrial invasion, performance of node dissection, and use of adjuvant radiation therapy. In a blinded fashion a pathologist reviewed all histopathology, and all molecular tests were performed on paraffin-embedded tissue samples. Statistical analysis was performed by χ 2 and McNemar's tests. Results. VSI was the only histopathological factor significantly related to positive lymph nodes and cancer recurrence ( P = 0.01), independent of grade and myometrial invasion. Aneuploidy, oncogene expression (p53, HER-2/neu, bcl-2), and hormone receptors were not significantly related to lymph node metastasis and cancer recurrence. Conclusions. The presence of vascular space invasion is a pathological factor independently associated with a risk of nodal metastasis and cancer recurrence in clinical stage I endometrial cancer. DNA ploidy, oncogene expression, and hormone receptor status do not have more predictive value than standard staging pathological criteria.
- Published
- 1997
146. Extent and nature of contacts between protein molecules in crystal lattices and between subunits of protein oligomers
- Author
-
Stephen H. Bryant, Swagata Dasgupta, Ganesh H. Iyer, Charles E. Lawrence, and Jeffrey A. Bell
- Subjects
chemistry.chemical_classification ,Crystal structure ,Biochemistry ,Oligomer ,Amino acid ,Hydrophobic effect ,Crystallography ,chemistry.chemical_compound ,Molecular recognition ,chemistry ,Structural Biology ,Aromatic amino acids ,Protein crystallization ,Molecular Biology ,Protein secondary structure - Abstract
A survey was compiled of several characteristics of the intersubunit contacts in 58 oligomeric proteins, and of the intermolecular contracts in the lattice for 223 protein crystal structures. The total number of atoms in contact and the secondary structure elements involved are similar in the two types of interfaces. Crystal contact patches are frequently smaller than patches involved in oligomer interfaces. Crystal contacts result from more numerous interactions by polar residues, compared with a tendency toward nonpolar amino acids at oligomer interfaces. Arginine is the only amino acid prominent in both types of interfaces. Potentials of mean force for residue-residue contacts at both crystal and oligomer interfaces were derived from comparison of the number of observed residue-residue interactions with the number expected by mass action. They show that hydrophobic interactions at oligomer interfaces favor aromatic amino acids and methionine over aliphatic amino acids; and that crystal contacts form in such a way as to avoid inclusion of hydrophobic interactions. They also suggest that complex salt bridges with certain amino acid compositions might be important in oligomer formation. For a protein that is recalcitrant to crystallization, substitution of lysine residues with arginine or glutamine is a recommended strategy.
- Published
- 1997
147. The evolution of Msx gene function: Expression and regulation of a sea urchin Msx class homeobox gene
- Author
-
Hailin Wu, Liang Ma, Robert E. Maxson, Jeffrey R. Bell, and Sonia L. Dobias
- Subjects
Embryology ,animal structures ,Molecular Sequence Data ,Ectoderm ,Germ layer ,Biology ,medicine ,Animals ,RNA, Messenger ,Cloning, Molecular ,In Situ Hybridization ,Homeodomain Proteins ,Genetics ,Base Sequence ,Sequence Homology, Amino Acid ,Embryogenesis ,Genes, Homeobox ,Gene Expression Regulation, Developmental ,Neural crest ,biology.organism_classification ,Strongylocentrotus purpuratus ,Gastrulation ,medicine.anatomical_structure ,Genes ,Sea Urchins ,embryonic structures ,Homeobox ,Archenteron ,Sequence Alignment ,Developmental Biology - Abstract
Msx- class homeobox genes, characterized by a distinct and highly conserved homeodomain, have been identified in a wide variety of metazoans from vertebrates to coelenterates. Although there is evidence that they participate in inductive tissue interactions that underlie vertebrate organogenesis, including those that pattern the neural crest, there is little information about their function in simple deuterostomes. Both to learn more about the ancient function of Msx genes, and to shed light on the evolution of developmental mechanisms within the lineage that gave rise to vertebrates, we have isolated and characterized Msx genes from ascidians and echinoderms. Here we describe the sequence and expression of a sea urchin (Strongylocentrotus purpouratus) Msx gene whose homeodomain is very similar to that of vertebrate Msx2. This gene, designated SpMsx, is first expressed in blastula stage embryos, apparently in a non-localized manner. Subsequently, during the early phases of gastrulation, SpMsx transcripts are expressed intensely in the invaginating archenteron and secondary mesenchyme, and at reduced levels in the ectoderm. In the latter part of gastrulation, SpMsx transcripts are concentrated in the oral ectoderm and gut, and continue to be expressed at those sites through the remainder of embryonic development. That vertebrate Msx genes are regulated by inductive tissue interactions and growth factors suggested to us that the restriction of SpMsx gene expression to the oral ectoderm and derivatives of the vegetal plate might similarly be regulated by the series of signaling events that pattern these embryonic territories. As a first test of this hypothesis, we examined the influence of exogastrulation and cell-dissociation on SpMsx gene expression. In experimentally-induced exogastrulae, SpMsx transcripts were distributed normally in the oral ectoderm, evaginated gut, and secondary mesenchyme. However, when embryos were dissociated into their component cells, SpMsx transcripts failed to accumulate. These data show that the localization of SpMsx transcripts in gastrulae does not depend on interactions between germ layers, yet the activation and maintenance of SpMsx expression does require cell-cell or cell-matrix interactions.
- Published
- 1997
148. Mixed mode and sequential oscillations in the cerium-bromate-4-aminophenol photoreaction
- Author
-
Jichang Wang and Jeffrey G. Bell
- Subjects
Materials science ,Time Factors ,Light ,Photochemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Aminophenols ,Catalysis ,Feedback ,Autocatalysis ,chemistry.chemical_compound ,Oscillometry ,Computer Simulation ,Mathematical Physics ,Phase diagram ,Oscillation ,Bromates ,Applied Mathematics ,Statistical and Nonlinear Physics ,Cerium ,Models, Theoretical ,Sulfuric Acids ,Bromate ,Bromine ,Coupling (physics) ,Light intensity ,Kinetics ,Amplitude ,chemistry ,Nonlinear Dynamics ,Chemical physics - Abstract
Cerium was introduced to the bromate-aminophenol photochemical oscillator to implement coupled autocatalytic feedbacks. Mixed mode and sequential oscillations emerged in the studied system, making it one of the few chemical oscillators known to support consecutive bifurcations in a batch system. The complex reaction behavior showed a strong dependence on the intensity of illumination supplied to the system. Removal of illumination during an oscillatory window affected both the frequency and amplitude of the oscillation but did not fully extinguish them, indicating that the cerium-bromate-4-aminophenol oscillator was photosensitive rather than photo-controlled. A moderate light intensity allowed for a slow evolution of the system, which proved to be critical for the emergence of transient complex oscillations. Variation of individual reaction parameters was carried out, which indicated that the development of complex oscillations occur in a narrow region and a phase diagram in the 4-aminophenol and sulfuric acid plane demonstrated this. Simulations provide strong support that transient complex oscillations observed experimentally arise from the coupling of two autocatalytic cycles.
- Published
- 2013
149. SpHbox7, a new Abd-B class homeobox gene from the sea urchinStrongylocentrotus purpuratus: Insights into the evolution of hox gene expression and function
- Author
-
Hongying Tan, Robert E. Maxson, Allan Zijian Zhao, Sonia L. Dobias, and Jeffrey R. Bell
- Subjects
Genetics ,Mesoderm ,animal structures ,biology ,Ectoderm ,Chordate ,biology.organism_classification ,Strongylocentrotus purpuratus ,Cell biology ,Gastrulation ,medicine.anatomical_structure ,embryonic structures ,medicine ,Homeobox ,Archenteron ,Hox gene ,Developmental Biology - Abstract
Hox genes, by virtue of their key functions in axial patterning, have long been thought to be pivotal players in the evolution of developmental mechanisms. Despite their potential importance in evolution, there is little information about Hox genes in animal groups that are most closely related to ancestral Chordates. Accordingly, we have taken the step of analyzing Hox gene expression and function in the sea urchin embryo, whose simple bilateral body plan is thought to resemble that of a stem organism in the Chordate lineage. Here we describe the isolation, sequences analysis and spatiotemporal expression pattern of a sea urchin (Strongylocentrotus purpuratus) Abd-B-like gene, designated SpHbox7. We show that this gene is one of at least two Abd-B-like genes in the S. purpuratus genome, a result that argues against the simple hypothesis that Hox gene duplications occurred only during the evolution of the chordates. SpHbox7 transcripts are first detectable in midblastula stage embryos, increase in amount during gastrulation, decline slightly by the pluteus stage, and are not detectable in any tissue of the adult. Whole mount in situ hybridization and antibody staining with an SpHbox7-specific antibody reveal that both SpHbox7 mRNA and protein are present throughout the embryo in the blastula. Subsequently, they are localized in the invaginating archenteron, secondary mesenchyme, and oral ectoderm. By the pluteus larva stage, SpHbox7 protein and mRNA are present in the gut, larval arms, and portions of the oral ectoderm. This complex and dynamic expression pattern suggests that SpHbox7 has a role in the patterning of the gut, the mesoderm, and the oral surface.
- Published
- 1996
150. Expression of anMsx homeobox gene in ascidians: Insights into the archetypal chordate expression pattern
- Author
-
Juan Chen, Liang Ma, Robert E. Maxson, Jing Zhou, Jeffrey R. Bell, Billie J. Swalla, William R. Jeffery, and Sonia L. Dobias
- Subjects
Genetics ,Mesoderm ,Molgula oculata ,animal structures ,biology ,ved/biology ,ved/biology.organism_classification_rank.species ,Organogenesis ,Ectoderm ,Molgula ,biology.organism_classification ,Molgula citrina ,medicine.anatomical_structure ,embryonic structures ,Notochord ,medicine ,Neural plate ,Developmental Biology - Abstract
The Msx homeobox genes are expressed in complex patterns during vertebrate development in conjunction with inductive tissue interactions. As a means of understanding the archetypal role of Msx genes in chordates, we have isolated and characterized an Msx gene in ascidians, protochordates with a relatively simple body plan. The Mocu Msx-a and McMsx-a genes, isolated from the ascidians Molgula oculata and Molgula citrina, respectively, have homeodomains that place them in the msh-like subclass of Msx genes. Therefore, the Molgula Msx-a genes are most closely related to the msh genes previously identified in a number of invertebrates. Southern blot analysis suggests that there are one or two copies of the Msx-a gene in the Molgula genome. Northern blot and RNase protection analysis indicate that Msx-a transcripts are restricted to the developmental stages of the life cycle. In situ hybridization showed that Msx-a mRNA first appears just before gastrulation in the mesoderm (presumptive notochord and muscle) and ectoderm (neural plate) cells. Transcript levels decline in mesoderm cells after the completion of gastrulation, but are enhanced in the folding neural plate during neurulation. Later, Msx-a mRNA is also expressed in the posterior ectoderm and in a subset of the tail muscle cells. The ectoderm and mesoderm cells that express Msx-a are undergoing morphogenetic movements during gastrulation, neurulation, and tail formation. Msx-a expression ceases after these cells stop migrating. The ascidian M. citrina, in which adult tissues and organs begin to develop precociously in the larva, was used to study Msx-a expression during adult development. Msx-a transcripts are expressed in the heart primordium and the rudiments of the ampullae, epidermal protrusions with diverse functions in the juvenile. The heart and ampullae develop in regions where mesenchyme cells interact with endodermal or epidermal epithelia. A comparison of the expression patterns of the Molgula genes with those of their vertebrate congeners suggests that the archetypal roles of the Msx genes may be in morphogenetic movements during embryogenesis and in mesenchymal-epithelial interactions during organogenesis.
- Published
- 1996
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