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Biomedical subjects

S Allen

Publications and source records attributed to S Allen.

At least 163 records · Page 9Linked to original sources
PubMed1993

Hospital-based versus community-based clinical education: comparing performances and course evaluations by students in their second-year pediatrics rotation.

BACKGROUND: Increasing use of outpatient settings for clinical education raises the question of their effectiveness compared with that of inpatient settings. METHOD: At the University of Minnesota Medical School-Minneapolis in 1987-88, the 190 second-year students participated in a six-week tutorial rotation introducing them to clinical pediatrics: 52 (27%) were in hospital settings and 138 (73%) were in community outpatient settings. Almost all the students (178) evaluated their rotations by responding to both structured and open-ended questions, using a Likert scale for the structured questions. At the completion of the second year, all 190 students took an objective structured clinical examination (OSCE) that included five pediatrics stations. Student's t-test was used to compare (1) the mean ratings the hospital-based and community-based students gave their pediatrics rotations and (2) the mean scores earned by the two groups of students on the five pediatrics stations in the OSCE. RESULTS: There were no statistically significant differences between (1) the two groups' mean ratings of the clinical experience overall or of the quality of teaching or (2) the groups' mean scores on any of the OSCE stations. CONCLUSION: That the hospital-based and community-based students performed comparably on the OSCE and gave similar evaluations of their pediatrics rotations supports the use of community practitioners to provide students with their initial clinical training. Moreover, community-based teaching sites replicate situations in which most students will eventually practice medicine.

Ambulatory Care↗
PubMed1993

Pleural effusion, tuberculosis and HIV-1 infection in Kigali, Rwanda.

OBJECTIVE AND METHODS: An increasing number of diagnoses of pleural effusions (PE) have been made over the last 8 years in the Department of Internal Medicine of the Centre Hospitalier de Kigali, Rwanda. In order to determine the aetiology of PE and to examine its possible association with HIV-1 infection, we performed an aetiological work-up, including thoracocentesis and pleural punch biopsy, of all new patients with PE of undetermined aetiology referred to the Division of Pulmonary Diseases of the Department of Internal Medicine of the Centre Hospitalier de Kigali between 14 September 1988 and 16 October 1989. HIV-1 serological testing was performed for most of the patients. RESULTS: A total of 127 patients (81 men, 46 women; mean age, 34 years; range, 16-71 years) with PE of undetermined aetiology were enrolled. Pleural tuberculosis was diagnosed in 110 (86%) and confirmed histologically and/or bacteriologically in 90 (82%). Of 98 pleural tuberculosis patients tested for HIV-1-antibody, 82 (83%) were HIV-1-seropositive. Metastatic cancer was responsible for PE in six (5%) patients, Kaposi's sarcoma in three, lymphoma in one (all four HIV-1-seropositive), anaplastic carcinoma in one, and adenocarcinoma in one (both HIV-1-seronegative). Non-tuberculous pneumonia was documented in five (4%) patients and was associated with HIV-1 infection in four. Other causes of PE were congestive heart failure (three patients), decompensated cirrhosis (one), constrictive percarditis (one), or undetermined (one); only one of these patients was HIV-1-seropositive. CONCLUSIONS: We conclude that tuberculosis is the predominant cause of PE in our patients and is strongly associated with HIV-1 infection. Although less frequent, non-tuberculous pneumonia, Kaposi's sarcoma and lymphoma are other causes of HIV-1-associated PE. In an African area highly endemic for HIV-1 and Mycobacterium tuberculosis co-infection, PE should be considered a good marker of tuberculosis as well as HIV-1 infection.

AIDS-Related Opportunistic Infections↗
PubMed1993

Studies of metaphase and interphase chromosomes using fluorescence in situ hybridization.

Our measurements have bearing on the resolution with which maps can be constructed and abnormalities can be detected by studying the proximity of DNA sequences in metaphase and interphase chromosomes. The results of our analyses are summarized in Figure 8. Metaphase chromosomes are compacted sufficiently that it is impractical to order sequences separated by less than approximately 1 Mbp. In contrast, 100-kbp resolution can be obtained in interphase chromosomes. Distance measurements reveal that interphase chromatin behaves as a random polymer over distances up to 1-2 Mbp. At greater distances, higher order constraints, perhaps the dimensions of the individual chromosome domains, come into play. A caveat remains: Because the effect of the FISH procedure on native chromosome organization is not well understood, these conclusions may not be applicable to native chromatin. We have illustrated that FISH, with appropriately chosen probes, can supplement conventional cytogenetics in the study of chromosome abnormalities. The technique is increasingly being applied in research laboratories to detect and characterize chromosome abnormalities and point the way to the location of genes involved in human disease.

Chromosome Aberrations↗
PubMed1993

Family-centeredness of the Children's Health Care journal.

The extent to which authors of Children's Health Care articles showed increased attention to the elements of family-centered care following the publication of Shelton, Jeppson, and Johnson's (1987) book Family-Centered Care for Children with Special Health Care Needs was examined. A total of 223 parent-oriented and family-oriented articles published during the 1980 to 1991 period were analyzed. The findings showed greater incorporation of family-centered notions into published articles after versus before publication of the Shelton et al. book, although the year in which changes occurred and the magnitude of the changes were quite variable for different elements of care. In cases where increased attention was paid to the elements of care, different subsets of elements were more likely to be attended to by different authors.

Analysis of Variance↗
PubMed1993

Pregnancy and contraception use among urban Rwandan women after HIV testing and counseling.

OBJECTIVES: This study examined hormonal contraceptive use and pregnancy in urban Rwandan women, following human immunodeficiency virus (HIV) antibody testing and counseling. METHODS: A sample of 1458 childbearing urban Rwandan women aged 18 to 35 years was tested and followed for 2 years. RESULTS: At enrollment, 17% of 998 HIV-negative women and 11% of 460 HIV-positive women were pregnant, and 17% vs 23%, respectively, were using hormonal contraceptives. One year later, half of the HIV-positive and one third of the HIV-negative hormonal-contraceptive users had discontinued use. The 2-year incidence of pregnancy was 43% in HIV-positive and 58% in HIV-negative women. HIV-positive women with fewer than four children were more likely to become pregnant than those with four or more; this association persisted in multivariate analyses but was not noted among HIV-negative women. At the end of the study, over 40% of non-users said that they would use hormonal contraception if it was provided at the study clinic, but 40% of HIV-positive women desired more children. CONCLUSIONS: Research is needed to identify the practical and psychosocial obstacles to effective long-term contraception among HIV-positive women. HIV counseling programs must specifically address the issue of childbearing.

AIDS Serodiagnosis↗
PubMed1993

Change and opportunity in ambulatory care.

Non-inpatient care is assuming greater importance within the Australian health system. The management of the delivery of health services is becoming a responsibility of clinicians. Clinicians, nurses, managers and academics need to come together to advance these issues. This paper outlines the thinking at Monash Medical Centre, a new 747-bed tertiary hospital situated in the south-eastern suburbs of Melbourne.

Continuity of Patient Care↗
PubMed1993

Role of nutritional status and weight loss in HIV seroconversion among Rwandan women.

To investigate nutritional status and heterosexual human immunodeficiency virus (HIV) transmission, we performed a nested case-control study of sexually active, adult women in Kigali, Rwanda. Forty-five women who seroconverted during the 24-month study period were compared to 74 women who remained seronegative throughout the study. Seroconvertors and nonseroconvertors did not differ in preseroconversion serum levels of vitamin A, carotenoids, vitamin E, selenium, albumin, ferritin, or cholesterol. Weight loss, however, was a significant predictor of eventual HIV seroconversion. Subsequent seroconvertors lost an average of 1.5 kg during the first 6 months of the study compared with a 1.0-kg gain (p = 0.001) for nonconvertors. Nine of 27 (33%) seroconvertors, compared with one of 44 (2%) controls, lost at least 5 kg in the 6-month period beginning 1 year before their seroconversion (odds ratio, 21.5, 95% confidence interval 4.1-112). The association between weight loss and seroconversion was independent of other potential risk factors such as socioeconomic status, pregnancy, and genital ulcer disease. In addition to these findings for measured weight loss during follow-up, reported weight loss before enrollment was also a risk factor for subsequent seroconversion. Additional studies of heterosexual HIV transmission are needed to determine whether or not weight loss is causally related to susceptibility for HIV infection.

Adolescent↗
PubMed1992

Confidential HIV testing and condom promotion in Africa. Impact on HIV and gonorrhea rates.

OBJECTIVE: We evaluated the impact of human immunodeficiency virus (HIV) testing and counseling on self-reported condom and spermicide use and on corresponding HIV seroconversion and gonorrhea rates in urban Rwandan women. DESIGN: Prospective cohort study with 2 years of follow-up, comparison of outcome variables before and after an intervention, and condom use measured in a control group that did not receive the intervention. SETTING: Outpatient research clinic in Kigali, the capital of Rwanda. PARTICIPANTS: One thousand four hundred fifty-eight childbearing women, 32% of whom were infected with HIV, were enrolled in a prospective study in 1988, and followed at 3- to 6-month intervals for 2 years. Follow-up was available for 95% of subjects at year 1 and 92% at year 2. INTERVENTIONS: An acquired immunodeficiency syndrome (AIDS) educational videotape, HIV testing and counseling, and free condoms and spermicide were provided to all participants and interested sexual partners. MAIN OUTCOME MEASURES: Self-report of compliance with condom-spermicide use and observed incidence of HIV and gonorrhea. RESULTS: Only 7% of women reported ever trying condoms before the intervention, but 22% reported condom use with good compliance 1 year later. Women who were HIV-positive were more likely to adopt condom use than HIV-negative women (36% vs 16%; P < .05). Independent predictors of condom use, both in HIV-positive and in HIV-negative women, included HIV testing and counseling of the male partner, having a nonmonogamous relationship, and believing condoms were not dangerous. Human immunodeficiency virus seroconversion rates decreased significantly (from 4.1 to 1.8 per 100 person-years; P < .04) in women whose partners were tested and counseled. The prevalence of gonorrhea decreased substantially (13% to 6%; P < .05) among HIV-positive women, with the greatest reduction among condom users (16% to 4%; P < .05). CONCLUSION: A confidential HIV testing and counseling program was associated with increased use of condoms and reduced rates of gonorrhea and HIV in urban Rwandan women. The lack of risk reduction in HIV-negative women whose partner's serostatus was unknown was of concern. Interventions that promote HIV testing and counseling for both members of a couple should be considered in other high-prevalence areas.

AIDS Serodiagnosis↗
PubMed1992

Neuronal and glial plasma membrane carrier-mediated uptake of L-homocysteate is not selectively blocked by beta-p-chlorophenylglutamate.

The proposed action of beta-p-chlorophenylglutamate (chlorpheg) as a selective blocker of L-homocysteate uptake was studied in primary cultures of mouse brain neurons and astrocytes and in rat brain synaptosomes. The preparations were incubated with 1 microM to 10 mM L-homocysteate and D-aspartate in the absence and presence of 7.5 mM chlorpheg. In each preparation uptake of the two amino acids comprised a saturable uptake and a non-saturable (passive diffusion) component. L-Homocysteate was of at least 100-fold lower affinity than D-aspartate as a substrate for the amino acid transporter. Chlorpheg was shown to be essentially equieffective as a weak competitive inhibitor of only the saturable uptake of L-homocysteate and D-aspartate. It is concluded that chlorpheg is not a selective blocker of L-homocysteate uptake.

Amino Acid Transport Systems↗
PubMed1992

Follicular cystic ovaries and cystic endometrial hyperplasia in a bitch.

Treatment of cystic ovaries in a bitch was unsuccessful with human chorionic gonadotropin, but aspiration of the follicles at laparotomy was successful. Follicular aspiration is described, with special emphasis on preventing bursal adhesions. Aspiration of persistent follicles is a simple treatment for cystic ovarian disease that is nonresponsive to parenterally administered hormones. The persistent estrus associated with cystic follicles is a primary cause of cystic endometrial hyperplasia (CEH) and severe cases of CEH are associated with infertility. Rapid intervention (surgical or hormonal) will limit the severity of CEH and, therefore, decrease infertility in breeding bitches.

Animals↗
PubMed1992

Effect of serotesting with counselling on condom use and seroconversion among HIV discordant couples in Africa.

OBJECTIVE: To determine whether HIV testing and counselling increased condom use and decreased heterosexual transmission of HIV in discordant couples. DESIGN: Prospective study. SETTING: Kigali, the capital of Rwanda. SUBJECTS: Cohabiting couples with discordant HIV serology results. MAIN OUTCOME MEASURES: Condom use in the couple and HIV seroconversion in the negative partners. RESULTS: 60 HIV discordant couples were identified, of whom 53 were followed for an average of 2.2 years. The proportion of discordant couples using condoms increased from 4% to 57% after one year of follow up. During follow up two of the 23 HIV negative men and six of the 30 HIV negative women seroconverted (seroconversion rates of 4 and 9 per 100 person years). The rate among women was less than half that estimated for similar women in discordant couples whose partners had not been serotested. Condom use was less common among those who seroconverted (100% v 5%, p = 0.01 in men; 67% v 25%, p = 0.14 in women). CONCLUSIONS: Roughly one in seven cohabiting couples in Kigali have discordant HIV serological results. Confidential HIV serotesting with counselling caused a large increase in condom use and was associated with a lower rate of new HIV infections. HIV testing is a promising intervention for preventing the spread of HIV in African cities.

AIDS Serodiagnosis↗
PubMed1992

Predictors of mortality among HIV-infected women in Kigali, Rwanda.

OBJECTIVE: To better characterize the natural history of disease due to human immunodeficiency virus (HIV) infection in African women. DESIGN: Prospective cohort study over a 2-year follow-up period. PARTICIPANTS: A total of 460 HIV-seropositive women and a comparison cohort of HIV-seronegative women recruited from prenatal and pediatric clinics in Kigali, Rwanda in 1988. MEASUREMENTS: Clinical signs and symptoms of HIV disease, AIDS, and mortality. MAIN RESULTS: Follow-up data at 2 years were available for 93% of women who were still alive. At enrollment, many seropositive women reported symptoms listed in the World Health Organization (WHO) clinical case definition of AIDS, but these were nonspecific and often improved over time. The 2-year mortality among HIV-infected women by Kaplan-Meier survival analysis was 7% (95% CI, 5% to 10%) overall, and 21% (CI, 8% to 34%) for the 40 women who fulfilled the WHO case definition of AIDS at entry. In comparison, the 2-year mortality in women not infected with HIV was only 0.3% (CI, 0% to 7%). Independent baseline predictors of mortality in seropositive women by Cox proportional hazards modeling were, in order of descending risk factor prevalence: a body mass index of 21 kg/m2 or less (relative hazard, 2.3; CI, 1.1 to 4.8), low income (relative hazard, 2.3; CI, 1.1 to 4.5), an erythrocyte sedimentation rate exceeding 60 mm/h (relative hazard, 4.9; CI, 2.2 to 10.9), chronic diarrhea (relative hazard, 2.6; CI, 1.1 to 5.7), a history of herpes zoster (relative hazard 5.3; CI, 2.5 to 11.4), and oral candida (relative hazard, 7.3; CI, 1.6 to 33.3). Human immunodeficiency virus disease was the cause of death in 38 of the 39 HIV-positive women who died, but only 25 met the WHO definition of AIDS before death. CONCLUSIONS: Human immunodeficiency virus disease now accounts for 90% of all deaths among child-bearing urban Rwandan women. Many symptomatic seropositive patients may show some clinical improvement and should not be denied routine medical care. Easily diagnosed signs and symptoms and inexpensive laboratory tests can be used in Africa to identify those patients with a particularly good or bad prognosis.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Unfolding and refolding of hen egg-white riboflavin binding protein.

The unfolding and refolding of riboflavin-binding protein (RfBP) from hen egg-white induced by addition of guanidinium chloride (GdnHCl), and its subsequent removal by dialysis have been studied by c.d. and fluorescence for both the native and reduced protein. The reduction of its nine disulphide bonds causes a reduction in the secondary structure (alpha-helix plus beta-sheet) from 63% to 33% of the amino acid residues. Unfolding of the native protein occurred in two phases; the first involving a substantial loss of tertiary structure, followed by a second phase involving loss of secondary structure at higher GdnHCl concentrations. By contrast this biphasic behaviour was not discernible in the reduced protein. The loss of ability to bind riboflavin occurred after the first phase of unfolding. Comparison of unfolding of the holoprotein and apoprotein suggested that riboflavin has only a small stabilizing effect on the unfolding process. After removal of GdnHCl, the holoprotein, apoprotein and reduced protein assumed their original conformation. The significance of the results in relation to various models for protein folding is discussed.

Animals↗