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Biomedical subjects

S Allen

Publications and source records attributed to S Allen.

At least 199 records · Page 11Linked to original sources
PubMed1992

Senior medical students as simulated patients in an objective structured clinical examination: motivation and benefits.

Third and fourth year medical students were recruited to participate as simulated patients and examiners in an Objective Structured Clinical Examination (OSCE) administered for second year medical students. Students reported they were motivated to participate, not only by the honorarium, but because they believed the OSCE would be fun and interesting and because they were interested in medical education and in improving clinical evaluation. The third and fourth year medical students benefitted academically and financially from participation. Faculty benefitted by having a readily available source of enthusiastic and knowledgeable simulated patients.

Education, Medical, Undergraduate↗
PubMed1992

Systemic hypothermia in treatment of brain injury.

An extensive literature suggests that there are minimal complications of systemic hypothermia in humans at and above 30 degrees C for periods of several days. Intracranial hemorrhage has been found to complicate profound hypothermia (10-15 degrees C), and ventricular arrhythmias occur at temperatures below 30 degrees C. Our initial clinical studies were with 21 patients undergoing elective craniotomy cooled to 30-32 degrees C for 1-8 h (mean 4 h). Hypothermia was induced by surface cooling with water blankets. No complications were found. Among 11 patients with severe brain injury, cooling to levels below 32 degrees C was associated with ventricular arrhythmias in 1 patient and atrioventricular block in 1 patient. Asymptomatic hypokalemia was found routinely and treated with potassium replacement. No intracranial hemorrhage or other complications were found. With surface cooling, intravascular temperature dropped at 1.6 degrees C/h. Based on the safety of surface cooling to a core temperature of 32 degrees C for 48 h, we are conducting a randomized study of this level of hypothermia in patients with severe brain injury, cooled within 6 h of injury.

Body Temperature↗
PubMed1991

Human immunodeficiency virus infection in urban Rwanda. Demographic and behavioral correlates in a representative sample of childbearing women.

OBJECTIVE: --To determine behavioral and demographic risk factors for human immunodeficiency virus (HIV) infection in central Africa. DESIGN: --Cross-sectional survey. SETTING: --Kigali, Rwanda. PARTICIPANTS: --A representative sample of 1458 childbearing women aged 19 to 37 years who were recruited from outpatient prenatal and pediatric clinics at the only community hospital in the city. MAIN OUTCOME MEASURE: --Antibodies to HIV assessed by enzyme immunoassay and confirmed by Western blot or indirect immunofluorescence. RESULTS: --The HIV seroprevalence was 32% overall. Infection rates were higher in women who were single, in those in steady relationships that began after 1981, and in the 33% of women reporting more than one lifetime sexual partner. Women in legal marriages or monogamous partnerships had lower rates of infection, but even low-risk women had prevalences on the order of 20%. History of venereal disease in the past 5 years, although the strongest risk factor in a multiple logistic analysis (odds ratio, 2.7; 95% confidence interval, 2.0 to 3.7), was reported by only 30% of those infected. Having a male sexual partner who drank alcohol or who had higher income were significant risk factors for HIV infection in the multivariate analysis, but use of oral contraceptives and having an uncircumcised partner were not. CONCLUSIONS: --The epidemic of the acquired immunodeficiency syndrome in Rwanda has spread beyond high-risk groups to the general population of women without known risk factors. For most of these women, a steady male partner is the source of their HIV risk and therefore a vital target for intervention efforts.

Adult↗
PubMed1991

The behavior of a fast-responding barbituric acid potential-sensitive molecular probe in bovine heart submitochondrial particles.

The barbituric acid probe diBa-C2-(5) responds to the formation of a membrane potential (delta psi) in bovine heart submitochondrial particles (SMP) by a CCCP-reversible, 5-7 nm red shift of the probe absorption spectrum. This shift can be enhanced by the addition of nigericin, an observation that indicates that the probe is specifically sensitive to delta psi. Probe-SMP binding analyses indicate that, relative to the resting state, the ratio of the dye dissociation constant to the maximum number of binding sites decreases by a factor of 30 when delta psi is generated. This observation suggests that the origin of the potential-dependent shift of the probe absorption spectrum is increased occupancy of the SMP membrane by diBa-C2-(5). The time course of the ATP-induced diBa-C2-(5) spectral shift in SMP was complete in nominally 0.2 s and could be described by a single-exponential rate equation. There was no evidence for a slower-phase signal when the data collection time period was increased to 250 s. The apparent first-order rate constants obtained from the single exponential analyses of the barbituric acid ATP-generated signal, however, were a linear function of probe concentration at fixed SMP membrane concentration. The resulting second-order rate constant obtained by linear regression was nominally 1 x 10(7) M (dye)-1 s-1; this value is two to three orders of magnitude higher than that of a number of other well-established probes of delta psi in mitochondrial preparations. Based on the invariance of the kinetics of the oxidation of cytochromes c and c1 by ATP-driven reversed electron transport in the presence and absence of the probe, diBa-C2-(5) does not appear to permeate the SMP membrane on a time scale of milliseconds to several minutes.

Adenosine Triphosphate↗
PubMed1991

Incidence of hairy cell leukemia, mycosis fungoides, and chronic lymphocytic leukemia in first known HTLV-II-endemic population.

Unlike human T cell leukemia-lymphoma virus type I (HTLV-I), HTLV-II has not been convincingly linked to a malignancy. In the first 10 months of serologic screening for HTLV-I/II among blood donors in New Mexico in 1988-1989, HTLV-I/II infection was found in 27 donors. HTLV-I/II infection was present in 1.0%-1.6% of American Indian and 0.16%-0.27% of Hispanic donors compared with 0.009%-0.06% of non-Hispanic white donors. HTLV-II was identified by DNA amplification in 12 of 13 samples from Indian and Hispanic seropositive donors. Despite apparent endemic HTLV-II infection in these populations, New Mexico Tumor Registry data showed that the incidences of hairy cell leukemia, mycosis fungoides, and chronic lymphocytic leukemia were comparable among the three ethnic groups. A population with endemic HTLV-II infection has been identified, and there is no evidence of increased risk for these three malignancies in the endemic groups.

Blood Donors↗
PubMed1991

Human immunodeficiency virus and malaria in a representative sample of childbearing women in Kigali, Rwanda.

In 1986-1987 a consecutive sample of 3702 women presenting to prenatal and pediatric clinics at the only hospital in Kigali, Rwanda, was screened for human immunodeficiency virus (HIV) and malaria infection. The prevalence of HIV antibodies was 29%, and that of malaria parasites was 9%. HIV antibodies were more prevalent in women from the urban center than in those from the outskirts (31% vs. 20%, P less than .001), and malaria parasites showed the opposite prevalence pattern (8% vs. 15%, P less than .001); after stratifying by location, there was no association between HIV and the presence or degree of malaria parasitemia. HIV prevalence was 45% in women who had received a blood transfusion between 1980-1985 (before screening of donated blood began), and 28% among the great majority (94%) who had never been transfused. HIV prevalence was 44% in single mothers. 34% in women in common law unions, and 20% in those in legal marriages. These high rates of infection in the general population of Kigali highlight the need to develop effective programs for preventing further spread of sexually transmitted HIV.

Adult↗
PubMed1991

Adjuvant therapy of stage II breast cancer treated with CMFVP, radiation therapy and VATH following lumpectomy. A pilot trial.

A pilot study was undertaken to assess the feasibility, toxicity, and efficacy of combined radiation therapy and chemotherapy in the adjuvant treatment of node-positive. Stage II patients with breast carcinoma who had undergone lumpectomy. Therapy consisted of three phases, starting with a six-week CMFVP (cyclophosphamide, methotrexate, 5-fluorouracil, vincristine, prednisone) induction, followed by radiation therapy to the breast, and concluding with four cycles of VATH (vinblastine, Adriamycin, thiotepa, Halotesin). Twenty-seven patients were entered with an average age of 51.5 years (median 50 yrs) and a mean follow-up of 46.2 months. Twenty-three patients (85.2%) are alive and 19 (70.3%) disease free. There were no ipsilateral local recurrences. Cosmetic results were good to excellent in 26/27 patients. The doses of VATH were not compromised by the prior therapy. The regimen was found to be tolerable and is a reasonable approach in the adjuvant treatment of this particular patient population.

Adjuvants, Pharmaceutic↗
PubMed1991

Comparing students' feedback about clinical instruction with their performances.

Validation of students' feedback as a measure of teaching effectiveness has been problematic for courses teaching clinical skills. This is true in part because establishing a valid and reliable method of assessing students' mastery of clinical skills has been a stumbling block. Reported here is the correlation of students' performances on an objective structured clinical examination (OSCE) with previously and independently collected feedback from students. In 1987-88, 190 second-year medical students at the University of Minnesota Medical School--Minneapolis spent one fourth of a second-year clinical skills course on neurology randomly assigned to one of four teaching sites--hospitals A, B, C, and D. Following their rotations, 180 of the students completed usable feedback forms. The students were consistently and significantly more positive about the teaching at hospital A. At the end of the year, all 190 students were tested using an OSCE having 20 stations, four of which presented neurologic problems. The students who had the neurology course at hospital A performed better on all four neurology problems, and differences were statistically significant for two of the problems. Feedback in this case accurately reflected a more effective teaching program.

Education, Medical, Undergraduate↗
PubMed1991

Knowledge, attitudes, and perceived risk of AIDS among urban Rwandan women: relationship to HIV infection and behavior change.

We examined factors associated with perceived risk of AIDS, behavior change, and HIV infection in a representative sample of 1458 child-bearing urban women in Rwanda, central Africa. Although 68% of women reported only one lifetime partner, and the majority (87%) lived with a husband or steady partner, the prevalence of HIV antibodies was still high (32%). Before receiving their HIV test results, the women completed a questionnaire about AIDS knowledge, attitudes, and practices. Knowledge about HIV transmission was high, with 96-98% of women correctly identifying the three primary routes of infection. However, only 16% of women reported taking any action to avoid AIDS in the previous year, and most (11%) had done so merely by asking their male partners to change their behavior. Only 7% of women had ever tried condoms, and many (68%) thought they could be dangerous to use. Women who perceived themselves at risk of AIDS (57%) were more likely to report changing behavior; they were also more likely to be infected with HIV. Other factors associated with behavior change included having known someone with AIDS, having discussed AIDS with a male partner, and believing that condoms are not dangerous. Future interventions should enhance perception of risk, encourage male sexual partners to reduce risky behavior, and increase familiarity with condoms.

Adolescent↗
PubMed1990

The Auckland skin clinic tinea pedis and erythrasma study.

Three hundred consecutive patients attending the Auckland Hospital dermatology clinic were examined clinically and microbiologically for evidence of interdigital or plantar mycological or bacterial infection. One hundred and nine patients were shown by laboratory investigation to have an infection. Of these, only 89 displayed clinical signs of infection. Erythrasma, a desquamative condition caused by Corynebacterium minutissimum, was the commonest infection in this study. The commonest dermatophyte isolated was Trichophyton mentagrophytes var interdigitale. There was a significant rise in the incidence of both types of infection with age.

Adolescent↗
PubMed1990

Venous ulcers.

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Clothing↗
PubMed1990

Immunofluorescence localization of vinculin in ectoplasmic ("junctional") specializations of rat Sertoli cells.

We have investigated, using indirect immunofluorescence techniques, the possibility that vinculin is a component of Sertoli cell ectoplasmic specializations. Affinity-purified polyclonal antibodies produced against human platelet vinculin were used to probe fixed frozen sections of rat testis. Specific fluorescence occurs in Sertoli cell regions adjacent to spermatids and to basally situated junctional complexes, sites at which ectoplasmic specializations are known to occur. Staining also occurs in Sertoli cell regions associated with tubulobulbar complexes. The antibody also labels focal contacts in cultured human dermal fibroblasts, apical junctional sites of rat epididymal epithelium, and dense plaques of smooth muscle. Our results are consistent with the prediction that vinculin is likely a component of ectoplasmic specializations and are also consistent with the hypothesis that these structures are a form of actin-associated adhesion complex.

Animals↗
PubMed1990

Pharmacokinetics, biodistribution and dosimetry of 99Tcm(V)DMSA in humans with squamous cell carcinoma.

Technetium-99m (99Tcm)(V) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to evaluate squamous carcinoma (SCC) of the head and neck. This study evaluated the pharmacokinetics and biodistribution of 99Tcm(V)DMSA in patients with SCC and calculated the bone mass of a New Zealand White (NZW) rabbit. This data was then used to calculate the effective dose equivalent in man. A total of 16 patients were studied (5 with no tumour, 11 with tumour). 99Tcm(V)DMSA had a fast bi-exponential blood clearance in patients with no tumour (30 and 401 min) and patients with tumour (30 and 387 min) with no significant difference (p greater than 0.05) between the two groups. 99Tcm(V)DMSA had a fast cumulative urine excretion with mean half-times in non-tumour and tumour patients of 183 min and 244 min respectively. There was no significant difference (p greater than 0.05) between these two latter groups. The effective dose equivalent of 99Tcm(V)DMSA in man is 5.1 microSv/MBq.

Aged↗