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Background: The Vanderbilt Community Circle (VC2) was designed to provide all faculty, staff, and students within the entire Vanderbilt University Medical Center community a dedicated venue to discuss current events and ongoing societal issues., Approach: During the 2017-18 academic year, four VC2 events were held on: "Race, identity, and conflict in America," "Gun violence in America," "Gender in the workplace," and "Immigration in America." Facilitators guided participants to share their views and perspectives on these matters with pre-developed open-ended questions. Attendees started discussions in small groups and then eventually combined into a large one. Pre- and post-event surveys were administered to measure the program's effectiveness., Evaluation: One-hundred and twenty-four participants were included, 75 of whom completed both the pre- and post-event surveys. Sixty-four of the 75 (85%) agreed or strongly agreed that "multiple perspectives and opinions were represented" and 73% felt that their "own perspective was broadened on the issue." Most (89%) believed that the format and setting of the event was conducive to dialogue and discussion, and almost all (91%) reported that they would attend a similar event in the future. Groningen Reflection Ability Scale scores were high before (94 [25th-75th: 88-99]) and remained high after the events (93 [25th-75th: 88-93.3], p > 0.05)., Reflection: We successfully implemented a medical center-wide, recurring current events and dialogue forum in hopes of increasing reflection, unity, and understanding across our own community., (© 2021. The Author(s).)

The study replicated research on metacontingencies that used a chessboard simulating a simplified chess game, in a completely online environment, with participants in their homes. Dyads of participants had to work together moving two knights in L-shape. Each trial ended when the knights met in adjacent squares. The squares where the knights should meet (aggregate product [AP]) varied in two conditions, using an ABAB design. In conditions A, knights should meet anywhere on the chessboard, and there was no consequence. In conditions B, the matrix of reinforceable squares was gradually reduced in four phases and knights' encounters were followed by different messages when correct or incorrect (cultural consequences). In group 1, five dyads were allowed to communicate. In group 2, dyads had no access to video call. Results of group 1 corroborate the findings of the original studies that showed a decrease in APs variability from conditions A to B, when communication was allowed. Group 2 showed similar results, therefore extending to the setting that not allowed communication. The online platform XadrezWeb, developed for this study, was an important tool to program the interlocked behavior contingencies and collect data during social isolation., Competing Interests: Conflict of InterestNo potential conflict of interest was reported by the authors., (© Association for Behavior Analysis International 2022.)

Introduction: Choosing a medical specialty is one of the most crucial and difficult decisions made during medical school. Given that specialty exposure is among the most important factors in decision-making, the Careers in Medicine (CiM) multi-specialty elective was designed to provide clerkship students an avenue to explore three or more specialties of interest during a single elective., Methods: A cross-sectional study was conducted at Vanderbilt University School of Medicine using anonymous surveys and de-identified written reflections submitted by students enrolled in the CiM course between August 2015 and June 2018. Data were analyzed using a mixed-methods approach., Results: The majority of students reported the elective guided them in ruling out (80%) and ruling in (65%) specialties. About half (51%) of students decided between the procedural versus critical-thinking dichotomy. Finally, 80% of students reported that they would take the course again rather than a focused elective. Major themes identified from student reflections included course attributes, specialty impacts, and student values., Discussion: Implementation of a multi-specialty elective during the clerkship year was an effective way to help students understand their career values, gain early exposure to specialties not featured in core clinical curriculums, and determine future fields of interest., Supplementary Information: The online version contains supplementary material available at 10.1007/s40670-021-01311-0., Competing Interests: Conflict of InterestThe authors declare no competing interests., (© International Association of Medical Science Educators 2021.)

Objectives: Early mobility in the PICU is safe and feasible. However, PICUs continue to meet barriers to implementing early mobility. PICU providers were surveyed before and after initiating an early mobility protocol to determine perceived barriers and continued challenges in performing early mobility., Design: This single-center prospective study surveyed PICU providers regarding 26 potential barriers to early mobility using a five-point Likert scale. A survey was distributed 1 month prior to and 6 months after beginning an early mobility protocol., Setting: Free-standing academic tertiary care children's hospital., Subjects: PICU providers of various professions., Interventions: Implementation of PICU-wide early mobility protocol., Measurements and Main Results: Paired pre- and post-early mobility protocol implementation surveys from 97 providers were compared. System-based barriers decreased after implementation of the early mobility protocol, such as lack of guidelines (75-20%; p < 0.01), inadequate training (74-33%; p < 0.01), lack of early mobility orders (72-30%; p < 0.01), and delayed recognition of early mobility candidates (68-35%; p < 0.01). Difficulty coordinating early mobility sessions, although significantly decreased, still remained a concern for 66% of providers in the postsurvey. Lack of resources, specifically staff (85-82%; p = 0.68) and equipment (67-60%; p = 0.36), also remained significant barriers. Presence of an endotracheal tube was a barrier for only 29% of providers' post-early mobility protocol, compared with 69% prior (p < 0.01). Clinical instability remained a top concern (82-79%; p = 0.63) as well as agitation (74-67%; p = 0.23). Day shift providers, with more early mobility exposure, perceived fewer barriers compared with night shift providers. Ninety percentage of post-early mobility survey participants felt that early mobility positively impacted their patients., Conclusions: Implementation of an early mobility protocol significantly changed provider perceptions regarding barriers to early mobility. Certain factors, such as staff availability, coordination difficulty, equipment shortage, and patient clinical factors, continue to be significant challenges to early mobility in the PICU population.

Rhodococcus equi is a facultative intracellular bacterium causing severe pyogranulomatous pneumonia, ulcerative enterocolitis, and mesenteric lymphadenopathy in foals aged less than 6 months. Less frequently, this pathogen affects various other species, such as pigs, cattle, cats, and even humans. Although rhodococcosis is treated with a combination of antimicrobial agents, resistance is developed in some cases, and thus, antimicrobial susceptibility must be monitored and managed. Considering these limitations of the current therapy and unavailability of a vaccine to prevent the disease, research is particularly focused on the development of an effective vaccine against rhodococcosis. Most vaccines undergoing development utilize the virulence-associated protein (Vap) A antigen, which was identified previously as a key virulence factor of R. equi . Nevertheless, other proteins, such as VapG, present in most virulent R. equi strains, are also encoded by vap genes located on the R. equi bacterial virulence plasmid. In the present study, we evaluated the effect of VapG immunization on the survival of R. equi -challenged mice. We used attenuated Salmonella as a carrier for VapG ( Salmonella - vapG +), a procedure previously adopted to develop a VapA-based vaccine. We observed that vaccination with Salmonella - vapG + induced both an increased IFN-γ, IL-12, and TNF-α production, and a decreased bacterial burden in organs of the R. equi -challenged mice. Nevertheless, Salmonella - vapG + vaccination protected only 50% of the mice challenged with a lethal dose of R. equi . Interestingly, we observed an increased frequency of B cells in the spleen of Salmonella - vapG +-vaccinated mice and showed that Salmonella - vapG +-vaccinated R. equi -challenged B-cell-knockout mice did not reduce the bacterial burden. Given these results, we discussed the potential role of the humoral immune response induced by Salmonella - vapG + vaccination in conferring protection against R. equi infection, as well as the employment of VapG antigen for obtaining hyperimmune plasma to prevent rhodoccocosis in young foals.

Recent advances in glycobiology have revealed the essential role of lectins in deciphering the glycocodes at the cell surface to generate important biological signaling responses. ArtinM, a d-mannose-binding lectin isolated from the seeds of jackfruit (Artocarpus heterophyllus), is composed of 16 kDa subunits that are associated to form a homotetramer. Native ArtinM (n-ArtinM) exerts immunomodulatory and regenerative effects, but the potential pharmaceutical applicability of the lectin is highly limited by the fact that its production is expensive, laborious, and impossible to be scaled up. This led us to characterize a recombinant form of the lectin obtained by expression in Saccharomyces cerevisiae (y-ArtinM). In the present study, we demonstrated that y-ArtinM is similar to n-ArtinM in subunit arrangement, oligomerization and carbohydrate binding specificity. We showed that y-ArtinM can exert n-ArtinM biological activities such as erythrocyte agglutination, stimulation of neutrophil migration and degranulation, mast cell degranulation, and induction of interleukin-12 and interleukin-10 production by macrophages. In summary, the expression of ArtinM in yeast resulted in successful production of an active, recombinant form of ArtinM that is potentially useful for pharmaceutical application., (Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Paracoccin (PCN) is an N-acetylglucosamine-binding lectin from the human pathogenic fungus Paracoccidioides brasiliensis. Recombinant PCN (rPCN) induces a T helper (Th) 1 immune response when prophylactically administered to BALB/c mice, protecting them against subsequent challenge with P. brasiliensis. In this study, we investigated the therapeutic effect of rPCN in experimental paracoccidioidomycosis (PCM) and the mechanism accounting for its beneficial action., Methodology/principal Findings: Four distinct regimens of rPCN administration were assayed to identify which was the most protective, relative to vehicle administration. In all rPCN-treated mice, pulmonary granulomas were less numerous and more compact. Moreover, fewer colony-forming units were recovered from the lungs of rPCN-treated mice. Although all therapeutic regimens of rPCN were protective, maximal efficacy was obtained with two subcutaneous injections of 0.5 µg rPCN at 3 and 10 days after infection. The rPCN treatment was also associated with higher pulmonary levels of IL-12, IFN-γ, TNF-α, nitric oxide (NO), and IL-10, without IL-4 augmentation. Encouraged by the pulmonary cytokine profile of treated mice and by the fact that in vitro rPCN-stimulated macrophages released high levels of IL-12, we investigated the interaction of rPCN with Toll-like receptors (TLRs). Using a reporter assay in transfected HEK293T cells, we verified that rPCN activated TLR2 and TLR4. The activation occurred independently of TLR2 heterodimerization with TLR1 or TLR6 and did not require the presence of the CD14 or CD36 co-receptors. The interaction between rPCN and TLR2 depended on carbohydrate recognition because it was affected by mutation of the receptor's N-glycosylation sites. The fourth TLR2 N-glycan was especially critical for the rPCN-TLR2 interaction., Conclusions/significance: Based on our results, we propose that PCN acts as a TLR agonist. PCN binds to N-glycans on TLRs, triggers regulated Th1 immunity, and exerts a therapeutic effect against P. brasiliensis infection.

Background: Paracoccin is a dual-function protein of the yeast Paracoccidioides brasiliensis that has lectin properties and N-acetylglucosaminidase activities. Proteomic analysis of a paracoccin preparation from P. brasiliensis revealed that the sequence matched that of the hypothetical protein encoded by PADG-3347 of isolate Pb-18, with a polypeptide sequence similar to the family 18 endochitinases. These endochitinases are multi-functional proteins, with distinct lectin and enzymatic domains., Methodology/principal Findings: The multi-exon assembly and the largest exon of the predicted ORF (PADG-3347), was cloned and expressed in Escherichia coli cells, and the features of the recombinant proteins were compared to those of the native paracoccin. The multi-exon protein was also used for protection assays in a mouse model of paracoccidioidomycosis., Conclusions/significance: Our results showed that the recombinant protein reproduced the biological properties described for the native protein-including binding to laminin in a manner that is dependent on carbohydrate recognition-showed N-acetylglucosaminidase activity, and stimulated murine peritoneal macrophages to produce high levels of TNF-α and nitric oxide. Considering the immunomodulatory potential of glycan-binding proteins, we also investigated whether prophylactic administration of recombinant paracoccin affected the course of experimental paracoccidioidomycosis in mice. In comparison to animals injected with vehicle (controls), mice treated with recombinant paracoccin displayed lower pulmonary fungal burdens and reduced pulmonary granulomas. These protective effects were associated with augmented pulmonary levels of IL-12 and IFN-γ. We also observed that injection of paracoccin three days before challenge was the most efficient administration protocol, as the induced Th1 immunity was balanced by high levels of pulmonary IL-10, which may prevent the tissue damage caused by exacerbated inflammation. The results indicated that paracoccin is the protein encoded by PADG-3347, and we propose that this gene and homologous proteins in other P. brasiliensis strains be called paracoccin. We also concluded that recombinant paracoccin confers resistance to murine P. brasiliensis infection by exerting immunomodulatory effects.

Virulent strains of Rhodococcus equi have a large plasmid of 80-90kb, which encodes several virulence-associated proteins (Vap), including VapA, a lipoprotein highly associated with disease. We have previously demonstrated that oral immunisation with attenuated Salmonella enterica Typhimurium strain expressing the antigen VapA (STM VapA+) induces specific and long-term humoral and cellular immunity against R. equi. It was shown that VapA activates Toll-like receptor 2 (TLR2) on macrophages by establishing an interaction that ultimately favours immunity against R. equi infection. The purpose of this study was to evaluate the immune response triggered by nasal immunisation with STM VapA+ and to determine whether TLR2 supports the vaccine effect. We developed an optimised protocol for a single nasal immunisation that conferred protection against R. equi infection in mice, which was manifested by efficient R. equi clearance in challenged animals. Nasal vaccination with STM VapA+ has also induced protection in Tlr2(-/-) mice and mice with non-functional TLR4. Moreover, spleen cells of vaccinated mice augmented T-bet expression, as well as the production of IL-12, IFN-γ, nitric oxide and hydrogen peroxide. Notably, the population of CD4(+) T cells with memory phenotype significantly increased in the spleens of vaccinated mice challenged 1 or 5 months after immunisation. In these animals, the spleen bacterial burden was also reduced. When similar experimental procedures were performed in TLR2 knockout mice, an increase in CD4(+) T cells with memory phenotype was not observed. Consequently, we conclude that nasal vaccination with attenuated Salmonella expressing the R. equi virulence factor VapA confers long-lasting protection against experimental rhodoccocosis and that TLR2 engagement was not crucial to induce this protection but may be required for a long-term immune response., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Human infections with EHEC such as O157:H7 have been a great concern for worldwide food-industry surveillance. This pathogen is commonly associated with bloody diarrhea that can evolve to the life-threatening hemolytic uremic syndrome. Animals are the natural reservoir where this pathogen remains asymptomatically, in steps of ingestion and colonization of the bowel. The bacterium is shed in the feces, contaminating the surroundings, including water and food that are directed for human consumption. A major player in this colonization process is intimin, an outer membrane adhesion molecule encoded by the E. coli attachment and effacement (eae) gene that has been shown to be essential for intimate bacterial attachment to eukaryotic host cells. In an attempt to reduce the colonization of animal reservoirs with EHEC O157:H7, we designed a vaccine model to induce an immune response against intimin gamma. The model is based on its recombinant expression in attenuated Salmonella, used as a suitable vaccine vector because of its recognized ability to deliver recombinant antigens and to elicit all forms of immunity: mucosal, systemic, and humoral responses. To test this model, mice were orally immunized with a S. enterica serovar Typhimurium strain carrying the pYA3137eaeA vector, and challenged with E. coli O157:H7. Here we show that immunization induced the production of high levels of specific IgG and IgA antibodies and promoted reduction in the fecal shedding of EHEC after challenge. The live recombinant vaccine reported herein may contribute to the efforts of reducing animal intestinal mucosa colonization., (© 2012 The Societies and Blackwell Publishing Asia Pty Ltd.)

The fungus Paracoccidioides brasiliensis is a human pathogen that causes paracoccidioidomycosis, the most prevalent systemic mycosis in Latin America. The cell wall of P. brasiliensis is a network of glycoproteins and polysaccharides, such as chitin, that perform several functions. N-linked glycans are involved in glycoprotein folding, intracellular transport, secretion, and protection from proteolytic degradation. Here, we report the effects of tunicamycin (TM)-mediated inhibition of N-linked glycosylation on P. brasiliensis yeast cells. The underglycosylated yeasts were smaller than their fully glycosylated counterparts and exhibited a drastic reduction of cell budding, reflecting impairment of growth and morphogenesis by TM treatment. The intracellular distribution in TM-treated yeasts of the P. brasiliensis glycoprotein paracoccin was investigated using highly specific antibodies. Paracoccin was observed to accumulate at intracellular locations, far from the yeast wall. Paracoccin derived from TM-treated yeasts retained the ability to bind to laminin despite their underglycosylation. As paracoccin has N-acetyl-β-d-glucosaminidase (NAGase) activity and induces the production of TNF-α and nitric oxide (NO) by macrophages, we compared these properties between glycosylated and underglycosylated yeast proteins. Paracoccin demonstrated lower NAGase activity when underglycosylated, although no difference was detected between the pH and temperature optimums of the two forms. Murine macrophages stimulated with underglycosylated yeast proteins produced significantly lower levels of TNF-α and NO. Taken together, the impaired growth and morphogenesis of tunicamycin-treated yeasts and the decreased biological activities of underglycosylated fungal components suggest that N-glycans play important roles in P. brasiliensis yeast biology., (© 2011 Dos Reis Almeida et al.)

A miniature linguistic system was used to study acquisition of recombinative symbolic behavior. Three studies evaluated the teaching conditions of conditional discriminations with printed and spoken pseudowords that could potentially generate recombinative reading. Fifty-four college students across all studies learned to match 12 printed pseudowords to 12 spoken pseudowords. Some also matched pictures to the same spoken words. Each two-syllable pseudoword was formed by symbols from an arbitrarily created alphabet composed of four vowels and four consonants. Letters had univocal correspondence with phonemes. Recombinative receptive reading, comprehensive reading, and textual responding to pseudowords were periodically assessed. Experiment 1 (n  =  20) showed that recombinative reading increased as the number of trained words composed of the same symbols increased. Experiment 2 (n  =  14) showed that overtraining the same two words did not produce recombinative reading for most participants. Experiment 3 (n  =  20), in which training with pictures was omitted, showed that elemental control by within-syllable units can develop even when the trained pseudowords are meaningless (not related to pictures). The present results support the utility of the miniature linguistic system methodology for identifying and controlling environmental determinants of rudimentary reading skills.

Treatment of Aspergillus niveus with 30 μg tunicamycin/ml did not interfere with α-glucosidase production, secretion, or its catalytic properties. Fully- and under-glycosylated forms of the enzyme had similar molecular masses, ~56 kDa. Moreover, the absence of N-glycans did not affect either pH optimum (6.0) or temperature optimum (65°C). The K(m) and V(max) values of under- and fully-glycosylated forms of α-glucosidase were similar when assessed for hydrolysis of starch (~0.6 mg/ml, ~350 μmol glucose per min per ml), maltose (~0.54 μmol, ~330 μmol glucose per min per ml) and p-nitrophenyl-α-D: -glucopyranoside (~0.54 μmol, ~8.28 μmol p-nitrophenol per min per ml). However, the under-glycosylated form was sensitive to high temperatures probably because, in addition to stabilizing the protein conformation, glycosylation may also prevent unfolded or partially folded proteins from aggregating. Binding assays clearly showed that the under-glycosylated protein did not bind to concanavalin A but has conserve its jacalin-binding property, suggesting that only O-glycans might be intact on the tunicamycin treated form of the enzyme.

The dimorphic fungus Paracoccidioides brasiliensis is the causative agent of paracoccidioidomycosis, the most frequent systemic mycosis in Latin America. Our group has been working with paracoccin, a P. brasiliensis lectin with MM 70 kDa, which is purified by affinity with immobilized N-acetylglucosamine (GlcNAc). Paracoccin has been described to play a role in fungal adhesion to extracellular matrix components and to induce high and persistent levels of TNFalpha and nitric oxide production by macrophages. In the cell wall, paracoccin colocalizes with the beta-1,4-homopolymer of GlcNAc into the budding sites of the P. brasiliensis yeast cell. In this paper we present a protocol for the chitin-affinity purification of paracoccin. This procedure provided higher yields than those achieved by means of the technique based on the affinity of this lectin with GlcNAc and had an impact on downstream assays. SDS-PAGE and Western blot analysis revealed similarities between the N-acetylglucosamine- and chitin-bound fractions, confirmed by MALDI-TOF-MS of trypsinic peptides. Western blot of two-dimensional gel electrophoresis of the yeast extract showed a major spot with M(r) 70,000 and pI approximately 5.63. Moreover, an N-acetyl-beta-D-glucosaminidase activity was reported for paracoccin, thereby providing new insights into the mechanisms that lead to cell wall remodelling and opening new perspectives for its structural characterization., (Copyright (c) 2009 John Wiley & Sons, Ltd.)

This paper reports results of two studies that sought to teach generative reading skills to a large group of Brazilian children who were exhibiting protracted failure in school. Inspired by Skinner's analysis of verbal relations and minimal verbal units, the methodology took advantage of certain characteristics of Portuguese. Many words in this language are comprised of two-letter syllabic units (e.g., BO+LA= ball, CA+BO= handle, LA+TA= can) that can be recombined to form new words (e.g., BOCA= mouth, BOTA= boot), thus establishing a route to generative reading via recombinative generalization. Such syllabic units were incorporated within curricular framework that used matching-to-sample and learning by exclusion methods to teach matching relations involving pictures, printed and spoken words, and printed and spoken syllables. Study 1 was conducted within a university-based learning center that maintained certain aspects of laboratory conditions. It showed that teaching textual relations between dictated and printed syllables could control procedurally the inter- and intra-participant variability observed in past studies that lacked this feature -resulting in virtually universally positive teaching outcomes. Study 2 was conducted in a public school programs that applied the same basic training methodology. Positive training outcomes in an experimental group were approximately 3-5 times greater than that in a placebo control group. Together, these studies illustrate that the functional analysis in Verbal Behavior is having a direct impact in educational science in Brazil. It has led to procedures that can be effectively translated from the laboratory to the community via delivery systems that can be implemented in the developing world.

Dps, found in many eubacterial and archaebacterial species, appears to protect cells from oxidative stress and/or nutrient-limited environment. Dps has been shown to accumulate during the stationary phase, to bind to DNA non-specifically, and to form a crystalline structure that compacts and protects the chromosome. Our previous results have indicated that Dps is glycosylated at least for a certain period of the bacterial cell physiology and this glycosylation is thought to be orchestrated by some factors not yet understood, explaining our difficulties in standardizing the Dps purification process. In the present work, the open reading frame of the dps gene, together with all the upstream regulatory elements, were cloned into a PCR cloning vector. As a result, the expression of dps was also controlled by the plasmid system introduced in the bacterial cell. The gene was then over-expressed regardless of the growth phase of the culture and a glycosylated fraction was purified to homogeneity by lectin-immobilized chromatography assay. Unlike the high level expression of Dps in Salmonella cells, less than 1% of the recombinant protein was purified by affinity chromatography using jacalin column. Sequencing and mass spectrometry data confirmed the identity of the dps gene and the protein, respectively. In spite of the low level of purification of the jacalin-binding Dps, this work shall aid further investigations into the mechanism of Dps glycosylation.

Background: All organisms living under aerobic atmosphere have powerful mechanisms that confer their macromolecules protection against oxygen reactive species. Microorganisms have developed biomolecule-protecting systems in response to starvation and/or oxidative stress, such as DNA biocrystallization with Dps (DNA-binding protein from starved cells). Dps is a protein that is produced in large amounts when the bacterial cell faces harm, which results in DNA protection. In this work, we evaluated the glycosylation in the Dps extracted from Salmonella enterica serovar Typhimurium. This Dps was purified from the crude extract as an 18-kDa protein, by means of affinity chromatography on an immobilized jacalin column., Results: The N-terminal sequencing of the jacalin-bound protein revealed 100% identity with the Dps of S. enterica serovar Typhimurium. Methyl-alpha-galactopyranoside inhibited the binding of Dps to jacalin in an enzyme-linked lectin assay, suggesting that the carbohydrate recognition domain (CRD) of jacalin is involved in the interaction with Dps. Furthermore, monosaccharide compositional analysis showed that Dps contained mannose, glucose, and an unknown sugar residue. Finally, jacalin-binding Dps was detected in larger amounts during the bacterial earlier growth periods, whereas high detection of total Dps was verified throughout the bacterial growth period., Conclusion: Taken together, these results indicate that Dps undergoes post-translational modifications in the pre- and early stationary phases of bacterial growth. There is also evidence that a small mannose-containing oligosaccharide is linked to this bacterial protein.

The present study investigated the effects of midazolam and pentylenetetrazole upon repeating and varying sequences of responses. Rats were exposed to a multiple schedule with two components. Under the VARY component, water was provided if the current sequence of four responses differed from each of the five previous ones; under the REPEAT component, water delivery was contingent upon a particular four-response sequence. Each component was signaled by specific exteroceptive stimuli. Overall, sequence variability was affected by midazolam, and to a lesser degree, by pentylenetetrazole. With the REPEAT contingency, drug administration increased behavior variation, thus reducing accuracy; with the VARY contingency, behavior variation and accuracy were not altered. These results were explained on the basis of the disruptive effects of both drugs upon the discriminative control exerted by previous responses within a sequence and by exteroceptive stimuli.

We studied the effects of delayed constructed-response identity matching on spelling with 6 first graders with histories of school failure. After training, the children learned to spell words to dictation and their cursive writing improved. These results replicate studies showing that delayed constructed-response matching establishes spelling. For 2 children, spelling of generalization words--words formed by recombining the syllables of training words--also improved. These results extend studies that have shown recombinative generalization in reading and spelling.

A fluid genome is a great advantage to prokaryotes, enabling quick adaptation to various types of ecological niches and to diverse environmental selective pressures. A substantial portion of these sudden changes is mediated by lateral gene transfer (LGT), through genetic recombination mechanisms, such as transformation, conjugation and transduction. The recent sequencing of several organisms has offered a new approach to the study of LGT, using comparison and analysis of nucleotide sequences dispersed throughout the genome of these species. This analysis in Choromobacterium violaceum has revealed four prophage and 12 insertion sequences, suggesting genetic exchange with several other bacterial species, including Salmonella enterica, Ralstonia and Xanthomonas. An Rhs (recombination hot spot) element (containing a vgr-like gene) was also observed, the function of which remains unknown, but it has a sequence related to species of Acinetobacter and Sphingomonas. These results support the role of LGT in the acquisition of new traits by C. violaceum.

Chromobacterium violaceum is a free-living bacterium commonly found in aquatic habitats of tropical and subtropical regions of the world. This bacterium is able to produce a large variety of products of biotechnological and pharmacological use. Although C. violaceum is considered to be non-pathogenic, some cases of severe infections in humans and other animals have been reported. Genomic data on the type strain ATCC 12472(T) has provided a comprehensive basis for detailed studies of pathogenicity, virulence and drug resistance genes. A large number of open reading frames associated with various mechanisms of drug resistance were found, comprising a remarkable feature of this organism. Amongst these, beta-lactam (penicillin and cephalosporin) and multidrug resistance genes (drug efflux pumps) were the most numerous. In addition, genes associated with bacitracin, bicyclomycin, chloramphenicol, kasugamycin, and methylenomycin were also found. It is postulated that these genes contribute to the ability of C. violaceum to compete with other bacteria in the environment, and also may help to explain the common drug resistance phenotypes observed in infections caused by this bacterium.

Six experimentally naive pigeons were exposed to concurrent variable-interval variable-interval schedules in a three-key procedure in which food reinforcement followed pecks on the side keys and pecks on the center key served as changeover responses. In Phase 1, 3 birds were exposed to 20 combinations of five variable-interval values, with each variable-interval value consistently associated with a different color on the side keys. Another 3 pigeons were exposed to the same 20 conditions, but with a more standard procedure that used a nondifferential discriminative stimulus on the two side keys throughout all conditions. In Phase 2, the differential and nondifferential stimulus conditions were reversed for each pigeon. Each condition lasted for one 5-hr session and one subsequent 1-hr session. In the last 14 conditions of each phase, the presence of differential discriminative stimuli decreased the time necessary for differential responding to develop and increased the sensitivity of behavior to reinforcement distribution in the 1st hr of training; during the last hours of training in each condition, however, the effects of the differential discriminative stimuli could not be distinguished from the effects of reinforcement distribution per se. These results show the importance of studying transitions in behavior as well as final performance. They may also be relevant to discrepancies in the results of previous experiments that have used nonhuman and human subjects.

The risk-benefit relationship of open heart surgery in octogenarians is not well established. Eighty consecutive patients over the age of 80 who underwent cardiac operations under cardiopulmonary bypass were evaluated. Twenty-five patients were in functional class IV, 42 in class III, and 13 in class II. Forty-four patients had only coronary artery bypass grafts (CABG), 12 only aortic valve replacement (AVR), 6 only mitral valve replacement (MVR), 12 CABG and AVR, 4 CABG and MVR, 1 CABG and aneurysmectomy, and 1 had resection of left atrial myxoma. Operative mortality (within 30 days) was 12.5% for the group. Mortality was related to bleeding, left ventricular failure, primary ventricular fibrillation, pulmonary failure, and renal failure. Mortality was higher in patients with (1) advanced functional class, (2) mitral valve replacement, (3) postoperative hemorrhage, and (4) associated pulmonary disease. While a generally conservative approach is recommended for octogenarian patients, many with life-threatening cardiac disease, especially those free of major multisystem illnesses, should not be denied the benefit of surgical treatment.

During a period of 6 years and 5 months, a group of 26 men and 16 women between 53 and 80 years of age underwent combined coronary artery bypass and mitral valve replacement. All patients were catheterized preoperatively, and hemodynamic and surgical variables were noted. In accordance with the variables, operative mortality was evaluated and compared among subgroups. Eight patients died, and the factors found to adversely change successful treatment were instability of ischemia, advanced New York Heart Association functional class, severe mitral regurgitation, associated aortic regurgitation, extensive coronary artery disease, the extent of left ventricular dysfunction as estimated by left ventricular end-diastolic pressure and ejection fraction, and elevated pulmonary vascular resistance. Prolonged operative time was also significant. The only variable that did not seem to influence mortality was the pathology type of mitral valve involvement. Analysis of our data confirms the high risk of coronary artery by pass combined with valve replacement for mitral regurgitation reported by others, and it appears advisable at present to exercise caution in recommending combined coronary artery by pass and mitral valve replacement in patients with extensive coronary artery disease and advanced left ventricular dysfunction. Pre-and postoperative utilization of afterload reduction, with the use of circulatory assist devices, may prove effective in some patients, and deserves special evaluation.

Consecutive catheterizations in 512 patients with mitral valve disease revealed 85 cases of mitral stenosis with systolic pulmonary artery pressures equal to or in excess of 100 mm Hg. Forty-four patients (51.8%) were in New York Heart Association functional Class IV; 30 (35.3%) were in Class III; and 11 (12.9%) were in Class II. Symptoms related to pulmonary capillary hypertension were prominent in 48 patients (56.5%) while the remaining patients showed signs of low cardiac output syndrome. Forty patients underwent surgery: mitral commissurotomy was performed in 26 patients; mitral valve replacement in 10 patients, and double valve replacement in four patients. Nitroprusside was infused into the pulmonary artery in six patients with severe perioperative low cardiac output; four of these patients survived. The overall operative mortality was 15% (six patients). Good long-term results were achieved in 30 cases.

Two patients who sustained cardiac rupture complicating recent myocardial infarction were salvaged by expeditious diagnosis and surgical treatment. The cases of 9 other similar patients have been reported in the English-language literature. The cases of these 11 patients were reviewed in an attempt to find common clinical, pathological, and therapeutic features that might have been instrumental in the successful outcome of this usually fatal complication.

Laser energy delivered through optical fibers can produce potent controlled thermal dissolution of human coronary obstructive disease, thus widening the stenotic vascular lumen. The ease of vaporization and penetration depends not only on the physical properties of the laser beam but also on the physical characteristics of the atherosclerotic plaque. Lipid-laden plaques are more easily vaporized compared with plaques that are heavily calcified. In atherosclerotic animal models studied in vivo, laser radiation produced a charred lining around the evacuated area and rapid regeneration of a new endothelial lining. After several weeks, the laser-induced crater was still evident, and thrombogenesis was not a significant complication. Focal aneurysmal dilatation may develop when there is thermal injury of the medial layer, and acute perforation can occur if severe laser burn is extended beyond the adventitial layer. Further technical advances and achievements are needed before laser recanalization becomes a clinical reality.

We propose that circumstances exist in which angiography is not necessary or is unwarranted for the diagnosis and treatment of carotid arterial disease. High quality real-time B-mode ultrasonographic imaging, combined with both pulsed gated, and continuous wave Doppler analysis, shows a remarkably close correlation with the pathologic abnormality identified at operation. Scanning in the vascular laboratory not only provides quick, noninvasive, accurate assessment of the atherosclerotic disease, it can also provide plaque and blood flow detail not previously attainable. Carotid surgery can be effectively and safely performed in selected patients with the aid of ultrasonography and Doppler analysis without the need for invasive angiographic imaging.

The results of 124 coronary reoperations performed during a 9-year period are reviewed, with the causes of failure of the initial operations and technical considerations in the reoperation procedures. The reoperative experience provided considerable insight as to why an initial revascularization might be unsuccessful. The three basic mechanisms which appeared to lead to recurrence of symptoms or late infarction following coronary bypass were (1) inadequate initial revascularization, (2) graft failure (occlusion or stenosis), and (3) progression of disease in the native circulation. Means of prevention and surgical techniques are reviewed in detail.