PubMed Health⌕ Search

Biomedical subjects

L Kuhn

Publications and source records attributed to L Kuhn.

90 records · Page 5Linked to original sources
PubMed1989

Smoking practices in the black township population of Cape Town.

A smoking prevalence survey was conducted in the black township population of Cape Town in order to assist with the planning of an anti-smoking campaign. Three townships were selected to reflect different levels of urbanisation: Langa (a settled urban community), Site B (a population of recent arrivals in the urban environment) and Khayelitsha (of intermediate urban status). Using World Health Organisation guidelines a school survey and an adult survey were conducted in each area. Of the 673 school pupils who were interviewed, 0.8% of girls and 23.7% of boys were current smokers. There was a trend to increasing smoking prevalence with increasing age among boys. After age-adjustment there was no difference in smoking prevalence between boys at the three schools. Information from 1320 adult respondents and 1,401 proxy-reported adults yielded an overall smoking prevalence of 7% (95% confidence interval 5.6-8.4%) for women and 60% (95% confidence intervals 57.5-62.5%) for men. Two-thirds of male smokers were smoking 10 or more cigarettes per day. The preferred mode of tobacco consumption in 87% of adults and 91% of school pupils was manufactured cigarettes. The survey has established three target groups for intervention in the black townships of Cape Town: boys in their early teens for prevention of initiation of smoking; adult men for assistance with smoking cessation; and girls and women to maintain their non-smoking status.

Adolescent↗
PubMed1989

Consecutive radiofluorography and silver staining of two-dimensional gel electrophoretograms: application in determining the biosynthesis of serum and tissue proteins.

The methodology for conventional radiofluorography of two-dimensional gels, followed by rehydration of the gel and subsequent silver staining, is described. The image obtained by radiofluorography is referred to as biosynthetic image, and the image obtained by silver staining as constitutive image. Since the two images are already in close register (the same gel), reliable identification of polypeptides by the two different assays is possible, and the comparison provides valuable information on the catabolism of each entity. The utility of this procedure is illustrated in experiments involving a labeling with L-[35S]methionine of an entire mouse. Both serum and tissue samples were analyzed by two-dimensional gel electrophoresis with the aim of determining several categories of polypeptides in terms of their biosynthetic rates and their composition.

Animals↗
PubMed1989

Determinants of cigarette smoking in the black township population of Cape Town.

There is concern about the increasing tobacco consumption in developing countries, especially in urban communities. Little information is available on the prevalence and determinants of smoking in black townships in South Africa. We therefore conducted a survey of the smoking practices in three such townships in Cape Town, in which 673 higher primary schoolchildren and 1320 adults were interviewed using a WHO questionnaire translated into Xhosa. Results were analysed using a multiple logistic regression model. In higher primary schoolpupils, boys smoked much more than girls [adjusted odds ratio (ORa) = 17.8; 95% confidence interval (CI): 5.2-60.9]; and smoking prevalence increased with age (ORa = 1.6; 95% CI: 1.3-1.9), peer pressure (ORa = 4.4; 95% CI: 1.9-6.9), and poor health knowledge (ORa = 3.1; 95% CI: 1.6-5.8). In adults, smoking prevalence was 53% in men compared to 6% in women. In men, an urban experience of 6 or more years was significantly associated with smoking (ORa = 1.9; 95% CI: 1.2-3.0) after adjustment for age, health knowledge and occupation. No association was found between level of education and smoking prevalence. Men in higher paid occupations smoked more than those in low paid occupations (ORa = 1.7; 95% CI: 1.0-2.8). Unemployment, however, was not associated with smoking prevalence. The findings emphasise the need for primary prevention of smoking in women and boys. Urbanisation and increased earning power appear to boost tobacco consumption in the absence of active anti-smoking efforts.

Adolescent↗
PubMed1988

Toward an objective classification of cells in the immune system.

The relative abundance of individual proteins shared among clones of lymphocytes provides a meaningful basis for cellular classification. Twelve clones of T cells (obtained by limiting dilution) were analyzed by two-dimensional gel electrophoresis for polypeptide content and then evaluated by the computational technique known as principal component analysis. As a result, relatedness of the clones was established and expressed in terms of taxonomic distances. The data show that a comprehensive and objective classification of the cells involved in the immune system can be approached.

Animals↗
PubMed1986

Parameters of the labeling of mitogen-activated murine lymphocytes by [35S]methionine for two-dimensional gel electrophoresis. I. Effect of culture conditions.

Labeling with [35S]methionine at a high specific activity is essential to the facile preparation of 2-dimensional gel electrophoretograms with the analytical 2-dimensional charge-size separation procedure (Anderson's ISODALT system). Mitogen-activated T and B lymphocytes subjected to low methionine concentrations would not proceed through cell cycle. In the case of activated B lymphocytes, the use of fetal bovine serum (FBS), dialyzed to lower endogenous methionine concentrations, prevented B cell growth even in the presence of otherwise satisfactory levels of methionine. High concentrations of [35S]methionine (greater than 300 mCi/1) induced B cell death, apparently by radiation damage. Despite these problems, good radioautograms and radiofluorograms of 2D electrophoretograms could be prepared by labeling activated B or T cells in bulk (10(6) cells/ml) with high specific activity [35S]methionine. The polypeptides labeled may be a biased sample since lymphoid cells do not proceed through cell cycle under these conditions. Small numbers (10(3] of activated T cells also yielded satisfactory samples but labeling of small numbers of activated B cells was not possible.

Animals↗
PubMed1985

Effect of visual training on the vertical vergence amplitude.

Visual training has an effect on the vertical vergence amplitudes. Three mature symptomatic patients exhibited a significant increase in the vertical vergence which compensates for the vertical heterophoria. Subjects with normal binocularity and hence no vertical heterophoria did not exhibit increased vertical vergence amplitudes after training.

Adult↗
PubMed1981

The role of diet in the pathogenesis and control of hyperlipidemia after renal transplantation.

Twenty-one Caucasian renal transplant recipients with hyperlipidemia and normal renal function were assessed with regard to their diet. Their average daily intake of energy and cholesterol was lower and the ratio of polyunsaturated to saturated fat higher in their diet than in that of a comparable urban Caucasian South African population. Nevertheless modification of their diets in one year produced a significant lowering of their body weight and a statistically significant drop in the mean plasma cholesterol (9.2 +/- 0.5 mmoles/l to 7.6 +/- 0.5 mmoles/l, P less than 0.05). Although the fall in plasma triglyceride in the group as a whole was not statistically significant (3.8 +/- 0.6 mmoles/l to 3.2 +/- 0.5 mmoles/l) the level did decrease substantially in 13 of the 21 patients (4.2 +/- 0.9 mmoles/l to 2.5 +/- 0.5 mmoles/l, P less than 0.01). It is suggested that diet has a definite role in the control of post-transplant hyperlipidemia but should probably be introduced immediately after immunosuppression is started and be coupled with a suitable exercise program for optimal effect.

Adult↗
PubMed1970

Peyer's patches: immunologic studies.

The immune capabilities of the Peyer's patches have been investigated by the use of an in vitro system. Despite our failure to stimulate Peyer's patch lymphocytes in vivo it appears that Peyer's patches behave immunologically as peripheral lymphoid tissues. Cultures prepared from the dissociated Peyer's patches of normal rabbits respond to sheep erythrocytes. The response is comparable to that obtained with spleen cultures from the same animals and is not dependent on the presence of the epithelial cells which line the lumen. Similar thymic cultures do not respond. Our experiments with cultures prepared from rabbits which have received one or two injections of SRC show that the Peyer's patches contain both IgM and IgG "memory" cells which have migrated from the spleen. The concentration of these cells in the spleen remains several hundredfold higher.

Animals↗
PubMedDate not supplied

Global analysis of lymphocyte gene expression: perturbation of H-9 cells by infection with distinct isolates of human immunodeficiency virus--an exposition by multivariate analysis of a host-parasite interface.

AIDS is a progressive disease associated with steady loss of helper T cells and several other functions. As the disease evolves, cytopathogenic human immunodeficiency (HIV) variants of increasing virulence can be isolated from the host. The HIV is an unusually variable genome by virtue of a low replication fidelity. In this report we describe our effort to test the hypothesis that there is a correlation between virus variability and cytopathogenicity, and further, that there is an "impact" of the virus infection on the expression of host cellular genes. To search for such a relationship, we infected H-9 cells (human CD4+ lymphoblastoid cell line) with each of 5 isolates of HIV of distinct origin and cytopathogenicity. To measure the influence of the virus infection on the expression of host cellular genes, shortly after infection, (3 h or 13 h), cells were radiolabeled and the radioactive polypeptides separated by two-dimensional gel electrophoresis. Radiofluorographs were prepared and analyzed to determine relative rates of biosynthesis of cellular polypeptides. To organize the large amounts of data found, cluster analysis and principal component analysis were used to expose the data in formats that allowed a model construction. The rates of biosynthesis of many cellular polypeptides were altered upon viral infection in terms of both enhancements and impairment of biosynthesis. Some of the variation in polypeptide synthesis was isolate-specific, while most alterations were of modest magnitude. There appears to be no "overall effect" associated with infection by a cytopathic variant of the virus. Polypeptides affected by the cytopathic variants were determined as targets for further investigation. The method used promotes the measurement of "ensemble" information that is characteristic of the process and it promotes the creation of models of virus action.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

An attempt to identify gene products related to the induction of an antiviral state in macrophages resistant and sensitive to IFN-gamma.

The activation of bone-marrow-derived macrophages by IFN-gamma (IFN gamma) partially inhibits mouse hepatitis virus 3 (MHV3) replication only in cells from resistant A/J mice, and not in cells originating from susceptible BALB/c mice. The computer image analysis of gels obtained from 2D-SDS-PAGE of extracted proteins of IFN gamma-activated A/J or BALB/c macrophages enabled us to identify and tag several gene products that were synthesized at elevated or diminished levels. Comparisons of the patterns of non-activated and IFN gamma-activated A/J macrophages revealed 3 gene products which increased, 1 which newly appeared, 6 which decreased and 20 which disappeared upon IFN gamma activation. The protein pattern of BALB/c macrophages revealed 13 gene products which increased, 8 which decreased and 8 which disappeared in IFN gamma-activated BALB/c macrophages. Whether these proteins are involved in the induction of an antiviral state against MHV3 growth remains to be investigated. Macrophages from mice with different genetic background (A/J and BALB/c), upon IFN gamma activation, behave differently at a molecular level, and this observation is consistent with their distinct expression of antiviral state against MHV3.

Animals↗
PubMedDate not supplied

The pattern of proteins synthesized in the liver is profoundly modified upon infection of susceptible mice with mouse hepatitis virus 3.

Susceptible BALB/c mice, after experimental infection with mouse hepatitis virus 3 (MHV3), revealed virus titres in the liver that increased gradually to a peak of 8 x 10(5) PFU/g of tissue after 3 days' infection, when the mice died of acute hepatitis. BALB/c mice were infected with MHV3, subsequently labelled in vivo with 35S-methionine, and then the liver preparations from both infected and non-infected animals were subjected to two-dimensional gel electrophoresis. Comparisons of the patterns by computer image analysis revealed 17 gene products which increased, and 8 gene products which decreased, upon virus infection in their two-dimensional gel spot intensity. We conclude that during MHV3 infection of a susceptible strain of mice, a major modification in protein synthesis occurs. The pattern alterations were not related to the virus gene products but were mostly endogenous mouse proteins. Whether these proteins are a result of a defence attempt by the animal, or are dictated by the virus in order to prevent a protective response from happening, remains to be shown.

Animals↗
PubMedDate not supplied

Molecular variants of human papillomavirus type 16 and risk for cervical neoplasia in South Africa.

Non-European variants of human papillomavirus (HPV) type 16 are generally associated with a greater risk of cervical neoplasia than European prototype variants. We investigated whether this association would persist in a population in which non-European HPV 16 variants were more common. We sequenced HPV 16 isolates in cervical samples collected from 93 Black South African women enrolled in a cervical cancer screening study and examined associations between cervical neoplasia identified though colposcopy with cervical biopsy and the specific HPV 16 variant identified. The European prototype variant (EP) was the most commonly identified variant in this population (47% of all isolates), but African variants (Af-1 and Af-2) were also quite common (41% of all isolates). In contrast to previous studies, we found no evidence that non-European variants were associated with an increased risk of neoplasia. Rather, most of the HPV 16-associated cancers were found in association with EP (71% of 14 cases). In this setting where African HPV 16 variants were common, no increased risk for cervical neoplasia was found among women with these variants compared with other HPV 16 variants.

Adult↗
PubMedDate not supplied

Changes over time in survival of children after AIDS diagnosis in New York City.

We determined whether survival of children following AIDS diagnosis is improving over time through 1991. AIDS surveillance data from New York City Department of Health on 914 pediatric AIDS patients, diagnosed between 1979 and 1991 and presumed due to maternal-infant HIV transmission, were analyzed. Survival following AIDS diagnosis, established from hospital records and death certificates, was compared by calendar year of initial diagnosis using Kaplan-Meier lifetable analysis. Cox Proportional Hazards regression models were used to compare survival for patients diagnosed earlier or later in the decade, controlling for age at diagnosis, presenting opportunistic illness, and gender of the child. Patients diagnosed with AIDS from October 1987 to September 1989 survived longer, median survival 17 months after diagnosis, than patients diagnosed before September 1987, median survival 10 months (relative risk [RR] = 0.76; 95% confidence intervals [CI] = 0.62, 0.93). Patients diagnosed from October 1989 to December 1991 also survived a median of 17 months. Secular improvements in survival after AIDS diagnosis remained after controlling for age at diagnosis, presenting diagnosis, and gender, even if deaths within three months of diagnosis were excluded. These data suggest that for recent years, survival following AIDS diagnosis in those contracting the infection through maternal-infant transmission has been prolonged. Possible explanations for these findings include both methodological issues (changes in diagnostic criteria, incomplete ascertainment of deaths) and substantive issues (developments in therapeutic interventions and management of pediatric AIDS).

Acquired Immunodeficiency Syndrome↗