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Biomedical subjects

W D Sawyer

Publications and source records attributed to W D Sawyer.

At least 19 recordsLinked to original sources
PubMed1997

Teaching and assessing clinical skills: a competency-based programme in China.

The objective of this study was to develop a competency-based clinical skills teaching and assessment programme in China utilizing modern teaching techniques. Medical teachers from three schools agreed on items for inclusion in the complete physical examination of an asymptomatic adult, an outline for an adult and paediatric history, and important interviewing skills. Lesson plans, performance checklists, and written and videotape training materials were developed. Standardized patients were trained at one school to assist with the teaching at that school and with the assessment at all three schools. A national, a provincial, and a local medical school in China were used. Before beginning the new curriculum for students in their first year of clinical training, baseline data were collected on skills of students at various levels of training in the previous curriculum at all three schools. Although in the previous curriculum there was some improvement in clinical skills among advanced compared to more junior students, performance was lower than expected by staff. One year after implementation of the new curriculum, students were evaluated. These students significantly outperformed their counterparts as well as the more senior level students tested the previous year. This project has established a competency-based teaching and assessment programme in China that allows for rapid improvement in the clinical skills of students. Within a short time, a sophisticated group of medical educators has been formed, who now function as consultants to other educators in their own country. Many aspects of this programme are being adapted throughout China and are applicable to medical schools throughout the world.

Attitude↗
PubMed1992

A new program to enhance the teaching and assessment of clinical skills in the People's Republic of China.

The authors describe the history and current state of development of an ongoing and still-evolving collaboration--between three Chinese medical schools, the China Medical Board of New York, Inc. (CMB), and one of the authors (PLS) and her staff at the University of Massachusetts Medical School--to enhance the teaching and assessment of clinical skills in the schools. The program grew out of a request by the three schools to the CMB for assistance in improving their process of evaluating students. Its goal is to develop a uniform and comprehensive course for teaching and assessing basic clinical skills. Standardized patients are also being used as instructors and evaluators. The program is co-sponsored by the three schools and the CMB. Background is given about the CMB, its involvement in Chinese medical education, and its American perspective on the nature of education in Chinese institutions of modern medicine and the factors that can assist and impede educational change. The authors present the mechanisms of the program, the benefits that have occurred so far, and the problems encountered in creating the model curriculum to teach clinical skills that is now being implemented by the three schools. Future plans are outlined, including the hope that the three schools will serve as a resource and disseminate some or all aspects of the new approach to similar medical schools in China, and that the program can serve as a model for implementation of similar programs in other countries.

China↗
PubMed1980

High-molecular-weight antigenic protein complex in the outer membrane of Neisseria gonorrhoeae.

The outer membrane of Neisseria gonorrhoeae contains approximately 15 proteins, with 2 or 3 accounting for over 75% of the total protein mass. Samples of outer membrane from strain 2686 T4 analyzed by electrophoresis in 2% polyacrylamide gels revealed a band with an apparent molecular weight of 800,000. The band was protein material, as indicated by trypsin and pronase sensitivity and by L-[3H]proline incorporation. Peptidoglycan, nucleic acids, and carbohydrate were not detected in the band. Dye binding, L-[3H]proline incorporation, and labeling of solubilized outer-membrane proteins with 125I-labeled Bolton-Hunter reagent indicated that the band made up 10 to 13% of the total protein mass of isolated outer membranes. The material in the band was purified by gel filtration and, after reduction and alkylation, quantitatively recovered as subunits with an apparent molecular weight of 76,000. The protein in complex form was exposed at the cell surface, as evidenced by labeling whole cells with 125I by using a lactoperoxidase-catalyzed reaction and with CNBr-activated dextran. Rabbit serum raised against whole 2686 T4 gonococci contained antibody which reacted with the protein complex. The protein complex was detected in all gonococcal strains tested, but its presence could not be demonstrated in several other gram-negative species.

Antigens, Bacterial↗
PubMed1980

Cross-linking analysis of the outer membrane proteins of Neisseria gonorrhoeae.

The organization of outer membrane proteins of Neisseria gonorrhoeae was investigated by using two-dimensional dodecyl sulfate-polyacrylamide gel electrophoresis and cross-linking agents. A naturally occurring protein aggregate, which may be composed of two proteins of 50,000 molecular weight, was detected in all strains. Treatment of whole cells with cross-linking agents yielded several additional complexes, suggesting that other proteins are arranged in the outer membrane as near neighbors. The principal outer membrane protein (molecular weight, 34,000) cross-linked (i) to itself to form a complex whch appeared to be trimeric, (ii) to the 28,000-molecular-weight outer membrane protein to form a bimolecular comlex, and (iii) to the 28,000-molecular-weight outer membrane protein in a 3:1 ratio. The formation of these complexes was independent of (i) colony type, (ii) colony opacity, (iii) pH during growth, and (iv) presence of markers for drug resistance or hypersensitivity.

Bacterial Proteins↗
PubMed1979

Neisseria gonorrhoeae membrane microenvironment studied by spin-label electron spin resonance: comparison of colony types.

Spin-label electron spin resonance was used to characterize the microenvironment around spin probes which localize (i) in membranes, (ii) at the membrane surface, or (iii) in the cytoplasm of living Neisseria gonorrhoeae. Four colony types (T1, T2, T3, and T4) of gonococci were compared on the basis of the electron spin resonance parameters 2T parallel to, S (order parameter), and tau c (microviscosity). The concentration of spin label used had little or no effect on viability. T1 and T2 gonococci were found to have a more restricted environment for molecular motion of a membrane surface spin label than did T3 and T4. The membrane fluidity, as measured by a membrane lipid spin label, of T4 (S = 0.571) was significantly greater than that of T1 or T3 (S = 0.580). This difference was detected at 37 degrees C, at 25 degrees C, in agar-grown bacteria, and in exponential-phase cells. Studies using spin labels which probe different levels of the membrane indicated the presence of a membrane flexibility gradient. Cytoplasmic spin-label studies indicated that the cytoplasm of all gonococcal colony types was three to five times more viscous than water.

Cell Membrane↗
PubMed1977

Ethylenediaminetetraacetic acid-sensitive antiphagocytic activity of Neisseria gonorrhoeae.

Colonial types of Neisseria gonorrhoeae were examined for the presence of pilus-independent antiphagocytic activity. Type 3 and depiliated type 1 gonococci had a shearing- and protease-resistant antiphagocytic activity that was eliminated by treatment with ethylenediaminetetraacetic acid (EDTA) and that was not present on type 4 bacteria. Incubation of EDTA-treated bacteria 37 degrees C for 90 min resulted in fas prevented by antibiotics that block the final assembly of cell wall macromolecules that depend on the C55-isoprenoid carrier for export. These include both lipopolysaccharide and peptidoglycan. Restoration was, however, unaffected by drugs that interfere with the synthesis of peptidoglycan, but not that of lipopolysaccharide, and by inhibitors of protein synthesis. These data suggested that gonococci have an antiphagocytic mechanism in addition to the previously described determinant (presumably pili) that was removed by blending or by treatment with proteases. Of the two antiphagocytic activities, type 1 had both, type 3 had only the EDTA-sensitive component, and type 4 had neither.

Cilia↗
PubMed1977

Release of enzymes from human leucocytes during incubation with Neisseria gonorrhoeae.

The effect of Neisseria gonorrhoeae on release of enzymes from human leucocytes was determined. Supernatants from incubation mixtures containing leucocytes and gonococci were assayed for activity of the cytoplasmic enzyme, lactic acid dehydrogenase, as well as for activity of the hydrolytic enzymes, β-glucuronidase and lysozyme, which are found primarily in leucocyte granules. Thirty-minute incubation of leucocytes with pilated T1 gonococci resulted in a negligible release of lactic acid dehydrogenase and little release of β-glucuronidase even at bacteria to leucocyte ratios as high as 50 to 1. Lysozyme release, however, was significant at this ratio and at 20 to 1 but not at 5 to 1. Incubation with non-pilated T4 bacteria yielded no significant release of lactic acid dehydrogenase or β-glucuronidase, but it caused a significant release of lysozyme at bacteria to leucocyte ratios as low as 2 to 1. These results suggested that the lysozyme release might be related to the degree of phagocytic activity since, at low ratios, T4 was readily ingested but T1 was not. Consistent with this hypothesis, serum which promoted the phagocytosis of the pilated gonococci also stimulated lysozyme release at low ratios of T1 to leucocyte. Absorption of the serum with T1 abolished the opsonic effect and markedly diminished the amount of lysozyme released.

Glucuronidase↗
PubMed1973

Drug-resistant Escherichia coli and Klebsiella-Enterobacter in healthy adults in Thailand and the effect of antibiotic administration.

Antibiotic-resistant strains of Escherichia coli and, to a lesser extent, Klebsiella-Enterobacter were common in serial samples of the normal intestinal flora of healthy young adults in Thailand, and the resistance often was to multiple drugs and was transferable. Antibiotic administration promoted dominance of the flora by drug-resistant organisms regardless of the drug regimen and the predrug susceptibility pattern of the flora. The normal pattern was regained slowly after the cessation of drug administration.

Adult↗
PubMed1973

Studies on the virulence of Neisseria gonorrhoeae. I. Relation of colonial morphology and resistance to phagocytosis by polymorphonuclear leukocytes.

Colonial varieties of Neisseria gonorrhoeae that are associated with virulence, types 1 and 2, were more resistant to phagocytosis by rabbit exudative polymorphonuclear leukocytes than colonial types of lesser virulence, types 3 and 4. Type 1 bacteria were resistant and type 4 gonococci were susceptible to phagocytosis by human polymorphonuclear leukocytes. Recent local type 1 isolates were similar in resistance to type 1 organisms of a standard laboratory strain (F62). Living and Formalin-treated, heat-killed, type 1 gonococci were equally resistant to phagocytosis. The antiphagocytic property of virulent colonial types was independent of leukotoxic action. Phagocytosis of both type 1 and type 4 gonococci by rabbit and human leukocytes was bactericidal. Rabbit leukocytes were superior to human leukocytes in killing gonococci. The results suggest that N. gonorrhoeae has virulence properties similar to those of extracellular bacterial pathogens, i.e., virulence is associated with antiphagocytic properties.

Animals↗
PubMed1973

Role of pili in the virulence of Neisseria gonorrhoeae.

Gonococci of the colonial types that are associated with virulence, types 1 and 2, have pili that enable the bacteria both to attach in vitro to human epithelial cells and to resist phagocytosis by polymorphonuclear leukocytes. These piliated gonococci also agglutinate various mammalian and chicken erythrocytes. Gonococci of an avirulent colonial type, i.e., type 4, have no pili and neither attach to epithelial cells or erythrocytes nor resist phagocytosis. Like the type 4 bacteria, mechanically or enzymatically (trypsin) depiliated type 1 gonococci failed to attach to epithelial cells and erythrocytes and were susceptible to phagocytosis. Pili of types 1 and 2 gonococci were antigenically similar. Both type 1 gonococci and pili isolated from them induced in rabbits antibody that (i) precipitated gonococcal pili in immunodiffusion, (ii) reacted with piliated gonococci as tested by indirect immunofluorescent analysis, (iii) inhibited attachment of piliated gonococci to both human epithelial cells and erythrocytes, and (iv) opsonized piliated gonococci.

Absorption↗
PubMed1972

Effect of exposure to the atmosphere on the infectivity of group A streptococci.

During exposure to the atmosphere, type 14 group A streptococci lost infectivity for mice more rapidly than they declined in viability. The loss of infectivity resulted from phenotypic, not genotypic, changes. Comparison of rates of loss of infectivity during exposure of capsulated and noncapsulated streptococci suggested that the principal effect of atmospheric exposure was on the capsule, a known determinant of infectivity. Accelerated drying promoted the loss of infectivity.

Air↗