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Biomedical subjects

D Fenner

Publications and source records attributed to D Fenner.

13 recordsLinked to original sources
PubMed2001

Development of a bench station objective structured assessment of technical skills.

OBJECTIVE: We have previously shown that objective structured assessment of technical skills performed in an animal model was an innovative, reliable, and valid method of assessing surgical skills. Our goal was to develop a less costly bench station objective structured assessment of technical skills and to evaluate the feasibility, reliability, and validity of this exam. METHODS: A seven-station examination was administered to 24 residents. The tests included laparoscopic procedures (salpingostomy, intracorporeal knot tying, closure of port sites) and open abdominal procedures (subcuticular closure, bladder neck suspension, repair of enterotomy, abdominal wall closure). All tasks were performed using life-like surgical models. Residents were timed and assessed at each station using three methods of scoring: a task-specific checklist, a global rating scale, and a pass/fail grade. RESULTS: Assessment of construct validity, the ability of the test to discriminate among residency levels, found significant differences on the checklist, global rating scale, time for procedures, and pass/fail grade by level of training. Reliability indices calculated with Cronbach's alpha were 0.77 for the checklists and 0.94 for the global rating scale. Overall interrater reliability indices were 0.91 for the global rating scale and 0.92 for the checklists. Total cost for replaceable parts and facilities was $1900. CONCLUSION: The less costly and more portable bench station objective structured assessment of technical skills can reliably and validly assess the surgical skills of gynecology residents. This type of examination can be a useful tool to identify residents who need additional surgical instruction, provide remediation, and may become a mechanism to certify surgical skill competence.

Adult↗
PubMed2000

Postoperative resolution of urinary retention in patients with advanced pelvic organ prolapse.

OBJECTIVE: This study was undertaken to determine whether surgery for advanced pelvic organ prolapse corrects the voiding dysfunction commonly associated with this condition and if so to evaluate the ability of preoperative voiding studies to predict such correction. STUDY DESIGN: We reviewed the records of all women who underwent surgery at our center between January 1996 and June 1999 for stage 3 or 4 pelvic organ prolapse. Patients were included in this review if they had a postvoid residual volume of >100 mL documented by catheterization on at least 2 occasions, had no normal postvoid residual volumes documented, and had undergone preoperative multichannel urodynamic testing that included an instrumented voiding study. Demographic and urodynamic data were analyzed for the ability to predict whether the elevated postvoid residual volume would be resolved after surgery. RESULTS: Thirty-five patients satisfied the criteria for inclusion in the review. Twenty-six had stage 3 pelvic organ prolapse and 9 had stage 4 pelvic organ prolapse. The mean preoperative postvoid residual volume was 226 mL (range, 105-600 mL). Thirty-one patients (89%) had normal postvoid residual volumes after surgery. As a predictor of elevated postoperative postvoid residual volumes, the preoperative voiding study (performed with the prolapse reduced) had a sensitivity of 66%, a specificity of 46%, a positive predictive value of 12%, and a negative predictive value of 93%. CONCLUSION: In our center a preoperative voiding study performed with the pelvic organ prolapse reduced most accurately predicted postoperative voiding function when results of the voiding study were normal. Most patients with advanced pelvic organ prolapse and elevated postvoid residual volume had normalization of the postvoid residual volume after surgical correction of the pelvic organ prolapse.

Aged↗
PubMed1998

Immunologic findings in workers formerly exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin and its congeners.

One hundred ninety-two workers in a German pesticide factory who were exposed to polychlorinated dibenzodioxins and -furans (PCDD/PCDF) were investigated for former and present diseases and laboratory changes of the immune system. Moreover, in a subgroup of 29 highly exposed and 28 control persons, proliferation studies were performed. In addition to assays such as blood count, immunoglobulins, serum electrophoresis, monoclonal bands, surface markers, autoantibodies, and lymphocyte proliferation, two new methods, the rise of tetanus antibody concentration after vaccination and the in vitro resistance of lymphocytes to chromate, were used to diagnose the morphologic and functional state of the immune system. There was no stringent correlation of actual PCDD/PCDF concentrations with the occurrence of infections or with one of the immune parameters. In addition, outcomes of the tetanus vaccination and the chromate resistance test were not correlated with PCDD/PCDF. However, the chromate resistance of lymphocytes stimulated by phytohemagglutinin of highly exposed persons was significantly lower than that for the control group. These findings indicate that the function of lymphocytes can be stressed and possibly impaired by high exposure to PCDD/PCDF.

Adult↗
PubMed1997

A profile of directors of clerkships in obstetrics and gynecology in the United States and Canada.

OBJECTIVE: To describe current professional activities, demographic profiles, and attitudes of directors of clerkships in university and community teaching sites. METHODS: Written surveys were mailed to departments of obstetrics and gynecology in the United States and Canada. Results were analyzed for differences in demographics, professional activities, and responses to statements describing career development of medical teachers and levels of institutional support. RESULTS: Responses from 132 of 148 (89%) medical schools and 67 of 96 (70%) known community-based clerkship directors showed no significant differences between the two groups in demographics or professional responsibilities. Three-quarters were men. The mean age was 47 years, mean duration as a faculty member 11 years, and mean tenure as clerkship director 8 years. One-half had been a clerkship director less than 5 years. The average clerkship director reported working approximately 56 hours per week, of which 44% was devoted primarily to patient care, 24% to teaching, and 18% to administration. These faculty members describe the activities of their position as fulfilling and worthy of recognition in the academic promotions process. CONCLUSION: Directors of clinical clerkships in obstetrics and gynecology in both university- and community-based programs spend about one-half of their time in teaching and administration. They find their work fulfilling and worthwhile. Profiles are consistent over time and comparable to those described by clerkship directors in other specialties.

Adult↗
PubMed1993

Chronic intrahypothalamic insulin infusion in the rat: behavioral specificity.

This study examines whether chronic intrahypothalamic (IH) insulin infusions suppress body weight and food intake directly or via effects on water intake or activity. Insulin (15 microU/h) was infused into the ventromedial hypothalamic nucleus of rats for 1 week. If IH insulin infusions primarily suppress water intake, animals should consume less water during insulin infusion in the absence of food. In the first experiment in this study, rats food deprived during IH insulin infusion did not drink significantly less than during vehicle infusion. This implies that IH insulin affects water intake secondarily to its impact on food intake. Insulin might suppress food intake and body weight by decreasing overall activity levels, including activity involved in ingestive behavior. In the second experiment, rats' activity on a running wheel was measured during IH insulin and vehicle infusion; activity increased during insulin infusion compared to vehicle infusion. These findings suggest that insulin's effects on food intake and body weight are via a mechanism that does not appear to directly influence water intake, and does not reduce overall activity levels.

Animals↗
PubMed1990

Hematological changes in calves exposed to a mixture of lipopolysaccharide and crude leukotoxin of Pasteurella haemolytica.

The purpose of this investigation was to determine if culture supernatants of Pasteurella haemolytica containing crude leukotoxin and lipopolysaccharide (CLCL) causes disseminated intravascular coagulopathy (DIC) when injected into calves. The effect of intraduodenal (ID) exposure followed by a subsequent subcutaneous (SC) inoculation of either heat-treated or untreated CLCL was evaluated. The relative contribution of the crude leukotoxin and lipopolysaccharide (LPS) to the virulence of P. haemolytica was evaluated. One group of calves received an ID inoculation of CLCL followed two weeks later by a SC inoculation of CLCL; one group received an ID inoculation of tissue culture medium followed two weeks later by a SC inoculation of CLCL; and a third group received an ID inoculation of CLCL followed two weeks later by a SC inoculation of heat-treated CLCL. Hematological parameters used to evaluate DIC included white cell count, platelet count, neutrophil number, fibrinogen, fibrin degradation products, one stage prothrombin time (OSPT), activated partial thromboplastin time, body temperature and clinical signs. Each parameter was measured in calves at 0, 2, 4, 6, 12 and 24 h following the SC inoculation of CLCL. Each group had significant changes over time in all parameters except body temperature. Calves that received a SC inoculation of heat-treated CLCL had smaller changes in all parameters except OSPT compared to the other groups. Results suggest that the LPS and leukotoxin of P. haemolytica exert additive effects on the coagulation cascade and number of peripheral leukocytes, and that the ID inoculation of CLCL does not affect the response of calves to a SC inoculation of toxin.

Animals↗
PubMed1988

[The significance of screening studies for the early detection of metastases in curatively operated breast carcinoma].

A retrospective analysis of 80 women with breast cancer operated on with curative intent showed that metastases developed within 8 years. The value of laboratory tests and radiological surveys for the early detection of metastases is considered. In fewer than 50% of the patients was the finding of a single abnormal laboratory result associated with tumor recurrence. However, when several findings were abnormal concomitantly this suggested tumor dissemination in about 90% of women. In 80% of the patients clinical symptoms were present at the time of tumor recurrence. In only 20% of the patients were metastases clinically silent. Since metastatic breast cancer cannot be cured by present treatment modalities, the relevance of detecting early recurrence is limited.

Adult↗
PubMed1983

Calcium uptake by isolated nerve endings: evidence for a rapid component mediated by the breakdown of phosphatidylinositol.

Several physiological stimuli, including neuronal depolarization, increase the production of phosphatidate (PA) from phosphatidylinositol (PI) and increase calcium fluxes across cell membranes. To determine if breakdown of PI is required for neuronal calcium uptake, we tested inhibitors of PI-specific phospholipase C on depolarization-dependent uptake of calcium by isolated brain synaptosomes. At a concentration of 0.1 mM these inhibitors reduced calcium uptake produced by depolarization for 1 to 3 sec, but did not affect uptake due to more prolonged depolarization. Exogenous PA also stimulated calcium accumulation by synaptosomes and this uptake was not reduced by the enzyme inhibitors. These results suggest that the rapid calcium influx produced by neuronal depolarization may be mediated by the breakdown of PI.

Animals↗
PubMed1983

Neurochemical effects of long-term ingestion of ethanol by Sinclair (S-1) swine.

Sinclair (S-1) miniature swine were given access to a mixture of ethanol and beer for three years. Control swine were fed an isocaloric diet with corn starch substituted for ethanol. Both groups had free access to tap water. The alcohol group consumed about 4 g ethanol/kg/day (about 50% of their caloric intake) resulting in plasma ethanol concentrations of about 100 mg/dl. Brain membranes were prepared for analysis of neurotransmitter receptor binding, membrane lipid composition and physical properties. Receptor studies demonstrated an increase in the binding of 3H-GABA to cortical and cerebellar membranes from the alcoholic pigs as compared to control. Binding of 3H-ligands to muscarine cholinergic, beta-adrenergic, alpha-adrenergic, dopamine and benzodiazepine receptors was not changed by chronic ethanol ingestion. These results are similar to those obtained in studies of human alcoholics by other investigators. The cholesterol content of myelin and synaptic plasma membranes was not altered by ethanol consumption. The fluorescence polarization of diphenylhexatriene, a measure of membrane order, did not detect any differences in the membranes from control or alcohol-treated swine either before or after in vitro exposure to ethanol. These results are different from those reported for rodents after short-term ethanol treatments and emphasize the importance of evaluating different models of experimental alcoholism.

Alcohol Drinking↗
PubMed1980

The role of contingencies and "principles of behavioral variation" in pigeons' pecking.

Staddon and Simmelhag's proposal that behavior is produced by "principles of behavioral variation" instead of contingencies of reinforcement was tested in two experiments. In the first experiment pigeons were exposed to either a fixed-interval schedule of response-contingent reinforcement, an autoshaping schedule of stimulus-contingent reinforcement, or a fixed-time schedule of noncontingent reinforcement. Pigeons exposed to contingent reinforcement came to peck more rapidly than those exposed to noncontingent reinforcement. Staddon and Simmelhag's "principles of behavioral variation" included the proposal that patterns (interim and terminal) were a function of momentary probability of reinforcement. In the second experiment pigeons were exposed to either a fixed-time or a random-time schedule of noncontingent reinforcement. Pecking showed a constant frequency of occurrence over postfood time on the random-time schedule. Most behavior showed patterns on the fixed-time schedule that differed in overall shape (i.e., interim versus terminal) from those shown on the random-time schedule. It was concluded that both the momentary probability of reinforcement and postfood time can affect patterning.

Journal Article↗