Self-care in medical education: effectiveness of health-habits interventions for first-year medical students.

PURPOSE: To examine changes in health habits (sleep, alcohol, and exercise) and the effects of an educational intervention promoting self-care on the emotional and academic adjustment of first-year medical students. METHOD: Fifty-four medical students completed questionnaires that assessed various health habits, alcohol use, depression severity, and areas of life satisfaction at the beginning of the semester, at mid-term, and at finals. Approximately half of the students received written feedback or participated in an educational discussion group at mid-term. RESULTS: The students demonstrated significant changes in health habits, with increases in alcohol consumption and decreases in exercise and socialization. The changes in health habits were predictive of both emotional and academic adjustment, with students who decreased in positive health habits, particularly socialization, being more depressed at finals. The feedback and educational interventions influenced some sleep and exercise behaviors, but the groups did not differ in overall emotional or academic adjustment. CONCLUSIONS: First-year medical students show significant changes in health habits as they adjust to medical school. An educational intervention demonstrated promising effects in changing these patterns, but self-care needs to be further elaborated to address the specific challenges associated with acute adjustment as well as with long-term stressors.     

Computer-aided mapping of the beta-adrenoceptor. 1. Explanation for effect of para substitution on blocking activity at the beta-1-adrenoceptor.

Anomalously low affinities for the beta-1-adrenoceptor are seen for members of a series of para-substituted N-isopropylphenoxypropanolamines in which the substituent is able to conjugate with the aromatic ring. The energy of conjugation was calculated using the AM1 semiempirical molecular orbital method and appears to correlate with the loss of binding energy, and hence affinity for the receptor. This suggests that binding is associated with movement of the substituent out of the plane of the aromatic ring due to steric interference with the receptor. A previously unrecognized binding site for aromatic groups off the para position is also identified.     

Does desmopressin acetate prophylaxis reduce blood loss after valvular heart operations? A randomized, double-blind study.

The effectiveness of prophylactic desmopressin acetate in reducing hemorrhage after cardiopulmonary bypass operations is controversial. We conducted a prospective, randomized, placebo-controlled, double-blind trial to determine its effectiveness and safety in such patients. Eighty-three evaluable patients undergoing valvular heart operations were randomized to receive desmopressin (0.3 microgram/kg) (41) or placebo (42) after cardiac bypass. Demographic characteristics were similar in both groups. There was no significant difference in total 24-hour blood loss between groups (desmopressin 1064.8 +/- 647.1 ml versus placebo 844.4 +/- 507.6 ml; p greater than 0.05), or in the requirement for red blood cell, platelet, or fresh frozen plasma transfusion, or for reexploration for control of hemorrhage. Neither was there a difference in the occurrence of thrombotic complications between groups. Analysis of factor VIII activity, von Willebrand factor, or von Willebrand factor multimers failed to show significant correlations with blood loss or differences between groups except for factor VIII activity, which was significantly higher in the desmopressin group 1 hour after operation than in the placebo group. A detailed comparative analysis of similar trials to determine the reasons for different outcomes suggests that desmopressin should not be used routinely as a prophylactic agent to reduce postsurgical hemorrhage, but that it may be beneficial when used in patients who already manifest excessive bleeding postoperatively.     

A novel 37-Kd adhesive membrane protein from cloned murine bone marrow stromal cells and cloned murine hematopoietic progenitor cells

The adhesion of hematopoietic progenitor cells to bone marrow stromal cells is critical to hematopoiesis and involves multiple effector molecules. Stromal cell molecules that participate in this interaction were sought by analyzing the detergent-soluble membrane proteins of GBI/6 stromal cells that could be adsorbed by intact FDCP-1 progenitor cells. A single-chain protein from GBI/6 cells having an apparent molecular weight of 37 Kd was selectively adsorbed by FDCP-1 cells. This protein, designated p37, could be surface-radiolabeled and thus appeared to be exposed on the cell membrane. An apparently identical 37- Kd protein was expressed by three stromal cell lines, by Swiss 3T3 fibroblastic cells, and by FDCP-1 and FDCP-2 progenitor cells. p37 was selectively adsorbed from membrane lysates by a variety of murine hematopoietic cells, including erythrocytes, but not by human erythrocytes. Binding of p37 to cells was calcium-dependent, and was not affected by inhibitors of the hematopoietic homing receptor or the cell-binding or heparin-binding functions of fibronectin. It is proposed that p37 may be a novel adhesive molecule expressed on the surface of a variety of hematopoietic cells that could participate in both homotypic and heterotypic interactions of stromal and progenitor cells.     

The effects of photoperiod on olfactory c-fos expression in prairie voles,Microtus ochrogaster

Reproduction stops among the majority of prairie voles (Microtus ochrogaster) during the winter. Short day lengths suppress male reproductive function dramatically in the laboratory, but photoperiod exerts only subtle effects on female reproductive function. Thus, the regulation of seasonal breeding in this species remains partially unspecified. In contrast to commonly studied rodents, female prairie voles do not undergo spontaneous estrous cycles; rather, they are induced into estrus by exposure to chemosignals expressed in conspecific male urine. In the present study, the hypothesis was tested that seasonal breeding among female prairie voles in the field reflects photoperiod-mediated changes in the responsiveness of the chemosensory system to male urine. Responsiveness was assessed by localizing the product of the c-fos immediate early gene with an immunocytochemical procedure. Female prairie voles were maintained in either long (LD 16:8) or short (LD 8:16) photoperiods from birth until adulthood, and exposed to either male urine or skim milk. Immunocytochemistry forfos protein revealed an increased number of immunoreactive cells within the accessory olfactory system of female prairie voles, including the accessory olfactory bulbs, granule cell layer, as well as the medial and cortical divisions of the amygdala 1 h after exposure to a single drop of urine as compared to individuals exposed to skim milk. The number of immunoreactivefos cells induced in females by conspecific male urine was also affected by photoperiod; short day females displayed fewer immunoreactivefos neurons in the accessory olfactory system as compared to long-day animal. Taken together, these results indicate that similar mechanisms underlie the responses of different rodent species to the chemosignals of conspecifics and that the pattern offos expression observed in the present study has functional significance for the regulation of reproduction in prairie voles.     

Pathological, immunocytochemical and microbiological findings in calf pneumonias associated with Haemophilus somnus infection

Pathological, immunocytochemical and microbiological findings in 32 cases of calf pneumonia associated with Haemophilus somnus infection are described. The majority of cases were "found dead" or died after a sudden onset pneumonia of less than 24 h duration. Lesions of exudative bronchopneumonia were present and the cases could be divided into two main groups on the basis of histopathological and immunocytochemical features. In group A, cases were dominated by necrotizing bronchiolitis, degeneration and necrosis of airway and alveolar exudates, severe alveolitis with accumulations of degenerate basophilic cells, interstitial inflammatory changes and the widespread distribution of H. somnus antigen in airways and alveoli. In Group B, necrotizing and degenerative changes were much less extensive and less severe and the overall appearance was of suppurative bronchopneumonia with H. somnus antigen much less widespread within the lungs. Alveolar oedema, hyaline membrane formation and alveolar epithelial hyperplasia were present in caudodorsal lung areas of several calves. No major differences were seen between the histopathology of lungs where H. somnus was the sole isolate and that of lungs where H. somnus was isolated along with other bacterial pathogens.     

Striatal monoamine neurotransmitters and metabolites in dominantly inherited olivopontocerebellar atrophy.

We measured the levels of the monoamine neurotransmitters and metabolites in striatum of 14 patients with end-stage dominantly inherited olivopontocerebellar atrophy (OPCA). On average, dopamine levels were reduced in putamen (-53%), caudate (-35%), and nucleus accumbens (-31%). However, individual patient values showed a wide variation, indicating that mild to moderate striatal dopamine loss is a common but not constant feature of OPCA. Seven patients had marked putamen dopamine loss (-62% to -81%) but without evidence of correspondingly severe substantia nigra cell damage; this suggests the possibility of a "dying-back" phenomenon in which nerve terminal loss precedes cell body degeneration. Severe substantia nigra cell loss with almost total (-95% to -99%) putamen and caudate dopamine depletion was present in two patients; however, none of the 14 patients had had a clinical diagnosis of parkinsonism or was receiving antiparkinsonian medication. Mean striatal serotonin levels were normal, whereas concentrations of the serotonin metabolite 5-hydroxyindoleacetic acid were elevated by 47% to 63%; this suggests increased activity of raphe dorsalis serotonin neurons innervating the striatum, which might aggravate the functional consequences of the dopamine deficit.     

2F3 Monoclonal Antibody Recognizes the O26 O-Antigen Moiety of the Lipopolysaccharide of Enterohemorrhagic Escherichia coli Strain 4276

Enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) organisms are groups of pathogenic strains whose infections are characterized by a typical lesion of enterocyte attachment and effacement. They are involved in enteric diseases both in humans and in animals, and EHEC strains can be responsible for hemolytic uremic syndrome in humans. Previously, it was shown that the 2F3 monoclonal antibody (MAb) is specific for the O26 EHEC and EPEC strains (P. Kerr, H. Ball, B. China, J. Mainil, D. Finlay, D. Pollock, I. Wilson, and D. Mackie, Clin. Diagn. Lab. Immunol. 6:610-614, 1999). As these groups of bacteria play an important role in pathology, the aim of this paper was to characterize the antigen recognized by the 2F3 MAb and its genetic determinant. A genomic locus containing the entire O-antigen gene cluster and half of the colanic acid gene cluster from an O26 EHEC strain was shown to be sufficient for the production of the antigen recognized by the 2F3 MAb in an E. coli DH5α strain. By transposon mutagenesis performed on the recombinant plasmid, all 2F3 enzyme-linked immunosorbent assay-negative mutants had their transposons inserted into the O-antigen gene cluster. The O-antigen gene cluster was also cloned from an O26 EHEC strain into the E. coli DH5α strain, which then produced a positive result with the 2F3 MAb. Further analysis of the type of lipopolysaccharides (smooth or rough) produced by the clones and mutants and of the O antigen of the 2F3-positive clones confirmed that the epitope recognized by the 2F3 MAb is located on the O antigen in the O26 EHEC and EPEC strains and that its genetic determinant is located inside the O-antigen gene cluster.