24 results on '"Svensson, Annika M."'
Search Results
2. Reversible Epstein-Barr Virus-Negative Lymphadenopathy and Bone Marrow Involved by Hodgkin’s Lymphoma in a Rheumatoid Arthritis Patient Undergoing Long-term Treatment with Low-Dose Methotrexate: A Case Report and Review of the Literature
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Svensson, Annika M., Jacobson, Erica R., indle, Barbara H., and Ospina, David
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- 2006
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3. Cystic tumor of the cerebellum with megaloblastic erythropoiesis
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Svensson, Annika M., Pang, Yijun, Moore, Nicholas J.E., and Tindle, Barbara H.
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Erythropoiesis -- Case studies ,Brain tumors -- Case studies ,Brain tumors -- Diagnosis - Published
- 2006
4. Pathology Consultation on Detection of Clostridium difficile
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Svensson, Annika M. and LaSala, P. Rocco
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- 2012
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5. Doctor Ex Machina: A Critical Assessment of the Use of Artificial Intelligence in Health Care.
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Svensson, Annika M and Jotterand, Fabrice
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ARTIFICIAL intelligence , *MEDICAL care , *PHYSICIAN-patient relations , *PHYSICIANS - Abstract
This article examines the potential implications of the implementation of artificial intelligence (AI) in health care for both its delivery and the medical profession. To this end, the first section explores the basic features of AI and the yet theoretical concept of autonomous AI followed by an overview of current and developing AI applications. Against this background, the second section discusses the transforming roles of physicians and changes in the patient-physician relationship that could be a consequence of gradual expansion of AI in health care. Subsequently, an examination of the responsibilities physicians should assume in this process is explored. The third section describes conceivable practical and ethical challenges that implementation of a single all-encompassing AI healthcare system would pose. The fourth section presents arguments for regulation of AI in health care to ensure that these applications do not violate basic ethical principles and that human control of AI will be preserved in the future. In the final section, fundamental components of a moral framework from which such regulation may be derived are brought forward, and some possible strategies for building a moral framework are discussed. [ABSTRACT FROM AUTHOR]
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- 2022
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6. Detection of a de novo Interstitial 2q Microdeletion by CGH Microarray Analysis in a Patient With Limb Malformations, Microcephaly and Mental Retardation
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Svensson, Annika M., Curry, Cynthia J., South, Sarah T., Whitby, Heidi, Maxwell, Teresa M., Aston, Emily, Fisher, Jamie, Carmack, C. E., Scheffer, Alicia, Abu-Shamsieh, Aimee, and Brothman, Arthur R.
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- 2007
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7. Role of superoxide anion in pancreatic islet blood flow regulation in anesthetized rats
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Svensson, Annika M., Sandler, Stellan, and Jansson, Leif
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- 2003
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8. Pediatric T-cell prolymphocytic leukemia with an isolated 12(p13) deletion and aberrant CD117 expression
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Bellone Michael, Svensson Annika M, Zaslav Ann-Leslie, Spitzer Silvia, Golightly Marc, Celiker Mahmut, Hu Youjun, Ma Yupo, and Ahmed Tahmeena
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T-cell Prolymphocytic Leukemia ,Pediatric T-cell Lymphomas ,Alemtuzumab ,TCR rearrangement ,CD117 ,12p13 ,Diseases of the blood and blood-forming organs ,RC633-647.5 ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Abstract T-cell Prolymphocytic leukemia (T-PLL) is a rare post-thymic T-cell malignancy that follows an aggressive clinical course. The classical presentation includes an elevated white blood cell (WBC) count with anemia and thrombocytopenia, hepatosplenomegaly, and lymphadenopathy. T-PLL is a disease of the elderly and to our knowledge it has never been described in the pediatric age group. We report a case of T-PLL in a 9 year old male who was initially diagnosed with T-cell acute lymphoblastic lymphoma (ALL), the diagnosis was later refined to T-PLL following additional analysis of bone marrow morphology and immunophenotype. Two unusual findings in our patient included CD117 expression and an isolated chromosomal 12(p13) deletion. The patient failed to respond to standard ALL induction chemotherapy, but achieved complete remission following treatment with a fludarabine and alemtuzumab-based regimen.
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- 2012
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9. Comparison of analytical and clinical performance of three methods for detection of Clostridium difficile
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LaSala, P. Rocco, Svensson, Annika M., Mohammad, Amin A., and Perrotta, Peter L.
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Glutamate -- Methods -- Health aspects ,Medical records -- Methods -- Health aspects ,Infection -- Methods -- Health aspects ,Enzymes -- Methods -- Health aspects ,Algorithms -- Methods -- Health aspects ,Algorithm ,Health - Abstract
* Context.--Diagnostic laboratory testing for Clostridium difficile infection has undergone considerable and rapid evolution during the last decade. The ideal detection method(s), which should exhibit high analytical and clinical sensitivity and specificity, remains undefined. Objective.--We sought to evaluate the analytical and clinical performance characteristics of three methods for the laboratory detection of C difficile. Design.--This study used 114 consecutive stool samples to compare three methods of C difficile detection: an enzyme immunoassay (EIA) for toxins A/B, a lateral flow membrane immunoassay for glutamate dehydrogenase (GDH), and a qualitative real-time polymerase chain reaction (PCR) assay. Medical records of all patients having ≥1 positive test result were reviewed to estimate the clinical likelihood of C difficile infection. Results.--Based upon laboratory result consensus values, analytical sensitivity was significantly higher for GDH (94%) and PCR (94%) assays than for toxin EIA (25%). Analytical specificity was significantly higher for PCR (100%) and EIA (100%) than for GDH assay (93%). In contrast, assay performance based upon clinical probability of C difficile infection suggested lower discriminatory power (ie, clinical specificity) of the more analytically sensitive methods. Conclusions.--Higher rates of C difficile detection will be realized upon implementation of GDH assay and/or real-time PCR-based testing algorithms than by testing with EIA alone. Further study is required to elucidate potential downstream costs for higher detection rates. (Arch Pathol Lab Med. 2012; 136:527-531; doi: 10.5858/arpa.2011-0305-OA), Laboratory testing of stool samples for toxigenic Clostridium difficile infection (CDI) has evolved considerably during the past 3 decades. Cytotoxicity to fibroblast monolayers, a key feature that helped to implicate [...]
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- 2012
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10. Hemostasis testing and therapeutic plasma exchange: Results of a practice survey.
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Zantek, Nicole D., Pagano, Monica B., Rollins‐Raval, Marian A., Smith, Roy E., Schmidt, Amy E., Crane, Jason E., Boral, Leonard I., Li, Yanhua, Svensson, Annika M., Yamada, Chisa, Wu, Yanyun, and Wong, Edward C. C.
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Introduction: Performing therapeutic plasma exchange (TPE) with albumin replacement decreases coagulation factor and platelet levels. No defined guidelines exist regarding laboratory testing to assess hemostasis in patients undergoing TPE. Materials and methods: A survey to evaluate hemostasis testing with TPE was distributed using online survey software. One response per institution was analyzed based on a hierarchical algorithm, excluding membrane filtration users, resulting in a maximum of 120 respondents per question. Descriptive analysis was performed with results reported as the number and/or frequency (%) of respondents to each question. Results: The practices represented vary by institution type, number of apheresis procedures per year, and performance of TPE on children. Prior to TPE planned with albumin replacement, many respondents obtain laboratory studies for almost all patients (54.9% outpatients and 68.7% inpatients); however, some do not routinely obtain laboratory studies (9.7% outpatients and 4.4% inpatients). Hemoglobin/hematocrit, platelet count, fibrinogen, partial thromboplastin time (aPTT), and international normalized ratio (INR) are obtained prior to all TPE by 62.5%, 53.4%, 31.0%, 18.1%, and 17.7% of respondents, respectively; however, 1.0%, 8.7%, 29.0%, 38.3%, and 35.4%, respectively, do not routinely obtain these studies. Variation was observed in laboratory threshold values for action; the most common reported were hemoglobin/hematocrit <7 g/dL or 21% (31.0%), platelet count <50 × 109/L (24.1%), fibrinogen <100 mg/dL (65.3%), aPTT >reference range and >1.5 times reference range (tied, 28.1%), and INR >1.5 (20.7%). Conclusions: Practice variation exists in hemostasis laboratory testing and threshold values for action with TPE. Further studies are needed to determine optimal hemostasis testing strategies with TPE. [ABSTRACT FROM AUTHOR]
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- 2019
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11. Age-induced changes in pancreatic islet blood flow: evidence for an impaired regulation in diabetic GK rats
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SVENSSON, ANNIKA M., OSTENSON, CLAES-GORAN, and JANSSON, LEIF
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Type 2 diabetes -- Research ,Aging -- Physiological aspects ,Physiology -- Research ,Islands of Langerhans -- Research ,Diabetes -- Physiological aspects ,Blood flow -- Research ,Biological sciences - Abstract
Svensson, Annika M., Claes-Goran Ostenson, and Left Jansson. Age-induced changes in pancreatic islet blood flow: evidence for an impaired regulation in diabetic GK rats. Am J Physiol Endocrinol Metab 279: E1139-E1144. 2000.--The present study aimed to compare longitudinal variations in islet blood perfusion in rats with different degrees of impairment of glucose metabolism. For this purpose, mildly diabetic Goto-Kakizaki (GK) rats, glucose intolerant [F.sub.1] hybrids of GK and Wistar (W) rats (H), and control W rats were examined at 5 wk, 12 wk, or 1 yr of age, using the microsphere technique for blood flow measurements. W rats showed progressively increasing islet blood flow (IBF) throughout the experiment. Both GK and H rats demonstrated increasing IBF between 5 and 12 wk. However, H rats showed no further increment in IBF at 1 yr, whereas GK rats displayed a pronounced decrease in IBF between 12 wk and 1 yr of age. The augmented IBF seen in older W rats may constitute an adaptation to the increasing demand for insulin secretion in aging rats. The inability to adapt to the increased demand for insulin secretion by upregulation of islet blood flow could contribute to the progressive deterioration of glucose metabolism seen in the aging GK rat. type 2 diabetes; aging
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- 2000
12. Hemostasis management and therapeutic plasma exchange: Results of a practice survey.
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Zantek, Nicole D., Boral, Leonard I., Li, Yanhua, Yamada, Chisa, Svensson, Annika M., Crane, Jason E., Smith, Roy E., Pagano, Monica B., Rollins‐Raval, Marian A., Schmidt, Amy E., Wong, Edward C. C., and Wu, Yanyun
- Abstract
Background: Patients undergoing therapeutic plasma exchange (TPE) may present with risks for hemorrhage or thrombosis. Use of replacement fluids devoid of coagulation factors will decrease factor levels and platelet levels. There are no established guidelines for hemostasis management in these situations. Materials and methods: A survey to evaluate current hemostasis management practice during TPE was conducted using online survey software. One response per institution was analyzed based on a hierarchical algorithm, excluding membrane filtration users, resulting in a maximum of 107 respondents. Descriptive analysis was performed with results reported as the number and frequency (%) of respondents to each question. Results: Apheresis Medicine physicians, alone (59.4%) or jointly with the requesting provider (29.2%), choose the replacement fluid. Based on a theoretical patient case receiving five TPEs approximately every other day, the percent of respondents who would use albumin with or without normal saline was 94.7% with no history of a bleeding or clotting disorder, 1.1% with active bleeding, and 8.8% with hypofibrinogenemia (<100 mg/dL) due to recent TPE. More respondents would use albumin with or without normal saline for replacement fluid when a minor invasive procedure (49.5%) vs a major surgery (8.9%) was performed 1 day before TPE. Replacement fluid selection varied among respondents for several other clinical conditions. The most frequent use for cryoprecipitate by respondents (14.3%) was hypofibrinogenemia. Conclusions: These survey results demonstrate wide interinstitutional variation in replacement fluid selection to manage hemostasis in patients undergoing TPE. Further studies are needed to guide optimal hemostasis management with TPE. [ABSTRACT FROM AUTHOR]
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- 2018
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13. Considerations of red blood cell molecular testing in transfusion medicine.
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Svensson, Annika M and Delaney, Meghan
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The field of transfusion medicine is on the threshold of a paradigm shift, as the technology for genotyping of red blood cell antigens, including US FDA-approved arrays, is now moving into standard practice. Access to cost-efficient, high-resolution genotyping has the potential to increase the quality of care by decreasing the risk for alloimmunization and incompatible transfusions in individuals on long-term blood transfusion protocols, including patient groups with hemoglobinopathies and other chronic diseases. Current and future applications of molecular methods in transfusion medicine and blood banking are discussed, with emphasis on indications for genotyping in various clinical scenarios. Furthermore, limitations of the current gold standard methodology and serology, as well as of contemporary molecular methodology, are examined. [ABSTRACT FROM PUBLISHER]
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- 2015
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14. Age-induced changes in pancreatic islet bloodflow: Evidence for an impaired regulation in...
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Svensson, Annika M. and Ostenson, Claes-Goran
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ISLANDS of Langerhans , *BLOOD flow , *GLUCOSE , *METABOLISM , *PHYSIOLOGY - Abstract
Compares longitudinal variations in islet blood perfusion in rats with different degrees of impairment of glucose metabolism. Group of rats showing progressively increasing islet blood flow ; Observation of adaptation to the increasing demand for insulin secretion in aging rats.
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- 2000
15. Pancreatic islet blood flow in the rat after administration of islet amyloid polypeptide or calcitonin gene-related peptide.
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Svensson, Annika M., Sandler, Stellan, Jansson, Leif, Svensson, A M, Sandler, S, and Jansson, L
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- 1994
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16. Gastric Inhibitory Polypeptide and Splanchnic Blood Perfusion: Augmentation of the Islet Blood Flow Increase in Hyperglycemic Rats
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Svensson, Annika M., Efendic, Suad, Östenson, CLaes-Göran, and Jansson, Leif
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- 1997
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17. The blood flow in pancreatico-duodenal grafts in rats: inhibition of nitric oxide synthase preferentially decreases islet blood flow
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Svensson, Annika M., Sandler, Stellan, and Jansson, Leif
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- 1995
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18. Implementation of a cost-effective unlabeled probe high-resolution melt assay for genotyping of Factor V Leiden.
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Svensson AM, Chou LS, Meadows C, Miller CE, Palais R, Sumner K, Wayman TC, Mao R, and Lyon E
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- Cost-Benefit Analysis, DNA Probes, Genotype, High-Throughput Screening Assays, Humans, Polymerase Chain Reaction instrumentation, Thrombophilia genetics, Transition Temperature, Factor V genetics, Genetic Testing methods, Mutation, Polymerase Chain Reaction economics, Polymerase Chain Reaction methods
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The Factor V Leiden mutation (FVL; c.1601G>A, p.Arg534Gln), the most common aberration underlying activated Protein C resistance, results in disruption of a major anticoagulation pathway and is a leading cause of inherited thrombophilia. A high-throughput assay for FVL mutation detection was developed using a single unlabeled probe on a high-resolution platform, the 96-well Roche 480 LightCycler (LC480) instrument. This method replaced the U.S. Food and Drug Administration-approved Roche Factor V Leiden kit assay on the LightCycler PCR instrument, decreasing total cost by 48%. The analytical sensitivity and specificity of the LC480 high-resolution assay approached 100% for the FVL mutation. Factor V mutations in proximity to the FVL locus may influence probe binding efficiency and melt characteristics. One out of three very rare variants tested in a separate study, 1600delC, was not distinguishable from FVL using the described high-resolution assay. However, a c.1598G>A variant, which changes the amino acid sequence from arginine to lysine at position 533, was detected by this high-resolution assay and confirmed by bidirectional sequencing. In the labeled probe LightCycler assay, the c.1598G>A variant was indistinguishable from the heterozygous FVL control. The c.1598G>A variant has not been described previously and its clinical significance is uncertain. In conclusion, the LC480 FVL assay is cost effective in a high-throughput setting, with capability to detect both previously described and novel FV variants.
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- 2011
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19. Detection of large rearrangements in the cystic fibrosis transmembrane conductance regulator gene by multiplex ligation-dependent probe amplification assay when sequencing fails to detect two disease-causing mutations.
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Svensson AM, Chou LS, Miller CE, Robles JA, Swensen JJ, Voelkerding KV, Mao R, and Lyon E
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- Chlorides analysis, DNA Mutational Analysis methods, Exons, Humans, Introns, Sweat chemistry, Cystic Fibrosis diagnosis, Cystic Fibrosis genetics, Cystic Fibrosis Transmembrane Conductance Regulator genetics, Gene Rearrangement, Mutation, Nucleic Acid Amplification Techniques methods
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Aims: Most of the over 1600 mutations and sequence variants identified to date in the cystic fibrosis transmembrane conductance regulator (CFTR) gene are point mutations or small deletions/insertions detectable by conventional sequencing. However, large rearrangements (deletions, duplications, or insertion/deletion mutations) have recently been reported to constitute 1-2% of CFTR mutations. The CFTR sequencing protocol at ARUP Laboratories interrogates the coding regions of all 27 exons and all intron/exon boundaries of the gene. This study was undertaken to determine whether testing for large gene rearrangements could improve the mutation detection rate., Results: Nine cases with abnormal quantitative pilocarpine iontophoresis sweat chloride (SC) values (>60 mEq/L) and 20 cases with borderline SC levels (40-60 mEq/L) with only one or no mutations detected by the ARUP 32 mutation panel, including the 23 mutations recommended by American College of Medical Genetics (ACMG) for carrier screening, followed by sequencing, were tested using a multiplex ligation-dependent probe amplification (MLPA) assay. MLPA analysis identified one deletion among nine patients with SC >60 who had previously been tested with sequencing. None of the cases with borderline SC levels showed rearrangements., Conclusion: The MLPA assay for detection of large rearrangements may be valuable in individuals with positive SC levels where one or no mutations have been identified by sequencing.
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- 2010
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20. Effects of glucagon-like peptide-1-(7-36)-amide on pancreatic islet and intestinal blood perfusion in Wistar rats and diabetic GK rats.
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Svensson AM, Ostenson CG, Efendic S, and Jansson L
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- Animals, Blood Glucose drug effects, Blood Glucose metabolism, Colon blood supply, Diabetes Mellitus, Experimental blood, Duodenum blood supply, Female, Insulin blood, Microspheres, Pancreas blood supply, Rats, Rats, Wistar, Regional Blood Flow drug effects, Diabetes Mellitus, Experimental physiopathology, Glucagon-Like Peptide 1 pharmacology, Intestines blood supply, Islets of Langerhans blood supply, Peptide Fragments pharmacology
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The aim of the present study was to evaluate the effects of GLP-1 [glucagon-like peptide-1-(7-36)-amide] on total pancreatic, islet and intestinal blood perfusion in spontaneously hyperglycaemic GK rats and normal Wistar rats using a microsphere technique. GK rats had hyperglycaemia and increased pancreatic and islet blood flow. Blood glucose concentrations were not affected when measured shortly (8 min) after GLP-1 administration in either GK or Wistar rats. GLP-1 had no effects on baseline pancreatic or islet blood flow in Wistar rats, but did prevent the blood flow increase normally seen following glucose administration to these animals. In GK rats, administration of GLP-1 decreased both pancreatic and islet blood flow. Glucose administration to the GK rats decreased pancreatic and islet blood flow. This decrease was not affected by pre-treatment with GLP-1. We conclude that administration of GLP-1 leads to a decrease in the augmented blood flow seen in islets of diabetic GK rats. The GLP-1-induced action on islet blood perfusion may modulate output of islet hormones and contribute to the antidiabetogenic effects of the drug in Type 2 diabetes (non-insulin-dependent diabetes).
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- 2007
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21. SELDI-TOF plasma profiles distinguish individuals in a protein C-deficient family with thrombotic episodes occurring before age 40.
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Svensson AM, Whiteley GR, Callas PW, and Bovill EG
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- Adult, Age Distribution, Age Factors, Algorithms, Biomarkers blood, Case-Control Studies, Decision Trees, Humans, Molecular Weight, Pedigree, Protein Array Analysis, Protein C Deficiency complications, Proteins chemistry, Risk Factors, Sensitivity and Specificity, Aging, Protein C Deficiency blood, Proteins metabolism, Proteomics methods, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Venous Thrombosis etiology
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We tested the hypothesis that differences in the low-molecular-weight (500-20,000 Da) proteomic profile of plasma may be detectable between members of a protein C-deficient family who have suffered thrombotic events before age 40 compared to family members without a history of venous thrombosis. Unfractionated plasma samples from members of a previously described large thrombophilic kindred with type I protein C deficiency were applied to ProteinChip weak cation exchange interaction arrays (WCX2; Ciphergen Biosystems, Fremont, CA, USA) and subjected to SELDI-TOF (surface-enhanced laser desorption/ionization time-of-flight) mass spectrometry using the Ciphergen PBSII ProteinChip System (Ciphergen Biosystems). Profiles were analyzed by a boosted decision-tree algorithm. When individuals who had presented with deep venous thrombosis (DVT) before the age of 40 (n = 21) were compared to age-matched, healthy family members (n = 50), the proteomic patterns defined by the decision-tree analysis could classify the entity of DVT before age 40 with 67% sensitivity, at a specificity of 86%. When a small group of cases with history of superficial venous thrombosis (n = 6) was added to the case group, the sensitivity was 87.5% at a specificity of 80%. These data support the hypothesis that members of the protein C deficient Vermont kindred II who suffer a thrombotic event before age 40 display significant differences in low-molecular-weight proteomics profile compared to those who remain disease-free. This is the first study to apply SELDI-TOF technology in conjunction with a bioinformatics tool to analyze low-molecular-weight proteomic patterns in patients with venous thrombosis.
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- 2006
22. Lack of compensatory increase in islet blood flow and islet mass in GK rats following 60% partial pancreatectomy.
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Svensson AM, Ostenson CG, Bodin B, and Jansson L
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- Animals, Diabetes Mellitus, Type 2 blood, Diabetes Mellitus, Type 2 physiopathology, Female, Glucose Tolerance Test, Insulin blood, Male, Models, Animal, Pancreas blood supply, Pancreatectomy, Rats, Rats, Inbred Strains, Rats, Wistar, Regional Blood Flow, Diabetes Mellitus, Type 2 surgery, Islets of Langerhans blood supply, Islets of Langerhans pathology
- Abstract
The effects of a 60% partial pancreatectomy were studied in hyperglycemic GK (Goto-Kakizaki) rats. Partial pancreatectomy or a sham operation was performed on 12-week-old female Wistar rats, GK rats or hybrids between male GK rats and female Wistar rats. Measurements of pancreatic blood flow and islet blood flow were performed by a microsphere technique 2 weeks after surgery. Glucose tolerance was decreased in hybrid compared with Wistar rats, and in GK rats compared with both hybrid and Wistar rats before surgery. Partial pancreatectomy induced minor changes in glucose tolerance. Wistar rats had a decreased islet mass following partial pancreatectomy. Both hybrid and GK rats showed a significant decrease in relative islet volume, but only GK rats in total islet mass, compared with Wistar rats 2 weeks after surgery. Pancreatic blood flow and islet blood flow did not significantly differ between sham-operated Wistar, hybrid or GK rats. After partial pancreatectomy, islet blood flow in relation to islet mass increased 3-fold in Wistar rats and 2-fold in hybrid rats. In contrast, GK rats showed no increase in islet blood flow following partial pancreatectomy. It is concluded that compensatory mechanisms after partial pancreatectomy are operating less efficiently in hybrid and GK rats.
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- 2005
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23. The protein C system in placental massive perivillous fibrin deposition.
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Svensson AM, Waters BL, Laszik ZG, Simmons-Arnold L, Goodwin A, Beatty BG, and Bovill EG
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- Abortion, Spontaneous pathology, Adult, Chorionic Villi ultrastructure, Enzyme Activation, Female, Humans, Immunoenzyme Techniques, Placenta Diseases complications, Pregnancy, Pregnancy Trimester, First, Thrombomodulin analysis, Abortion, Spontaneous etiology, Chorionic Villi chemistry, Fibrin analysis, Glycoproteins analysis, Placenta Diseases metabolism, Protein C analysis
- Abstract
Massive perivillous fibrin deposition (MPFD) is associated with intrauterine growth retardation and first-trimester and second-trimester spontaneous abortion. Histologically, villi near the maternal interface are completely surrounded by fibrinoid material. This work compared the expression of thrombomodulin (TM) and endothelial protein C receptor (EPCR) in early miscarriage specimens with and without MPFD. Ten specimens with a gestational age of 7-12 weeks (mean 10 weeks) and 10 age-matched miscarriage specimens lacking MPFD were sampled. Formalin-fixed paraffin-embedded sections were stained with monoclonal antibodies against TM and EPCR using an immunoperoxidase method. The slides were independently reviewed by two pathologists using a semiquantitative grading system. Among unaffected villi, there was no difference in staining for TM or EPCR in cases of massive perivillous fibrin deposition compared with the control group. In the MPFD cases, loss of membrane positivity was noted for both TM and EPCR at the junction between normal villous epithelium and villous epithelium with deposition of fibrin. This could imply an underlying defect of trophoblastic protein C activation. Alternatively, it may represent a degenerative change secondary to impedence of oxygen and nutrient supply to the trophoblastic epithelium.
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- 2004
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24. An immunohistochemical approach to monitor the prolactin-induced activation of the JAK2/STAT5 pathway in pancreatic islets of Langerhans.
- Author
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Brelje TC, Svensson AM, Stout LE, Bhagroo NV, and Sorenson RL
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- Animals, Biological Transport drug effects, Blotting, Western, Cell Nucleus metabolism, Cytoplasm metabolism, DNA-Binding Proteins analysis, Enzyme Activation drug effects, Glucagon analysis, Insulin analysis, Insulinoma, Islets of Langerhans chemistry, Islets of Langerhans ultrastructure, Janus Kinase 2, Microscopy, Confocal, Pancreatic Neoplasms, Phosphorylation, Phosphotyrosine metabolism, Rats, Receptors, Prolactin analysis, STAT5 Transcription Factor, Somatostatin analysis, Trans-Activators analysis, Tumor Cells, Cultured, DNA-Binding Proteins metabolism, Immunohistochemistry, Islets of Langerhans metabolism, Milk Proteins, Prolactin pharmacology, Protein-Tyrosine Kinases metabolism, Proto-Oncogene Proteins, Trans-Activators metabolism
- Abstract
This study examined whether an immunohistochemical method examining the subcellular localization of STAT5 could be used to characterize the activation of the JAK2/STAT5 pathway by prolactin (PRL) in intact cells or tissues. In the Ins-1 beta-cell line, STAT5A and STAT5B were distributed almost equally in the cytoplasm and the nucleus in unstimulated cells. STAT5A was also detected along the border of cells and in the perinuclear region. After exposure to PRL, the redistribution from the cytoplasm to the nucleus was much higher for STAT5B compared to STAT5A. This translocation represented 12% of the STAT5A and 22% of the STAT5B originally located in the cytoplasm before stimulation. In isolated rat islets of Langerhans, PRL stimulated the nuclear translocation of both STAT5A and STAT5B only in beta-cells. The expression of the PRL receptor only by beta-cells was confirmed with a rabbit polyclonal antiserum raised against the rat PRL receptor. It was estimated that 4% of STAT5A and 9% of STAT5B originally located in the cytoplasm was translocated to the nucleus after stimulation. The presence of a functional JAK2/STAT5 signaling pathway in all islet cells was demonstrated by the nuclear translocation of STAT5B in all islet cells (i.e., alpha-, beta-, and delta-cells) after stimulation with fetal calf serum. The nuclear translocation and tyrosine phosphorylation of STAT5B was biphasic, with an initial peak within 30 min, a nadir between 1 and 3 hr, and prolonged activation after 4 hr. In contrast, the tyrosine phosphorylation of STAT5A was also biphasic but its nuclear translocation peaked within 30 min and was then reduced to a level slightly above that observed before PRL stimulation. This method is able to detect changes in STAT5 activation as small as 2% of the total cell content. These observations demonstrate the utility of this approach for studying the activation of STAT5 in a mixed population of cells within tissues or organs. In addition, the dose response for the nuclear translocation of STAT5B in normal beta-cells was similar to those for changes in proliferation and insulin secretion in isolated rat islets. Therefore, the subcellular localization can be used to monitor the activation of STAT5 and it may be a key event in the upregulation of the pancreatic islets of Langerhans during pregnancy.
- Published
- 2002
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