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Biomedical subjects

L Kuhn

Publications and source records attributed to L Kuhn.

At least 73 records · Page 4Linked to original sources
PubMed1995

The effects of vitamin A supplementation on the morbidity of children born to HIV-infected women.

OBJECTIVE: The effects of vitamin A supplementation on morbidity of children born to human immunodeficiency virus (HIV)-infected women were evaluated in a population where vitamin A deficiency is not endemic. METHODS: A randomized, placebo-controlled trial of vitamin A supplementation was carried out in 118 offspring of HIV-infected women in Durban, South Africa. Those assigned to receive a supplement were given 50,000 IU of vitamin A at 1 and 3 months of age; 100,000 IU at 6 and 9 months; and 200,000 IU at 12 and 15 months. Morbidity in the past month was then recalled at each follow-up visit. Analysis was based on 806 child-months. RESULTS: Among all children, the supplemented group had lower overall morbidity than the placebo group (OR = 0.69; 95% confidence interval [CI] = 0.48, 0.99). Among the 85 children of known HIV status (28 infected, 57 uninfected), morbidity associated with diarrhea was significantly reduced in the supplemented infected children (OR = 0.51; 95% CI = 0.27, 0.99), whereas no effect of supplementation on diarrheal morbidity was noted among the uninfected children. CONCLUSION: In a population not generally vitamin A deficient, vitamin A supplementation for children of HIV-infected women appeared to be beneficial, reducing morbidity. The benefit was observed particularly for diarrhea among HIV-infected children.

Adult↗
PubMed1995

Human lymphocyte cDNA ordered library analyzed by 2D gel electrophoresis. 1. Pooling strategy and matching of gel patterns.

We have analyzed an ordered library of 4,608 cDNA clones from the CEM human leukemic cell line. The aim was to facilitate gene retrieval, to enable immediate access to cDNA clones and to provide information on the protein expression of the individual clones in a 2D gel readout. The matrix array of 24 x 16 x 12, each position of which contained lambda jacII phage from one plaque, enabled us to establish pools of clones along the three axes (24 pools of complexity 192 cloned entities, 16 pools of complexity 288 and 12 pools of complexity 384). The total cDNA complexity is here reduced to such a level that spots which in more complex gels served as landmark spots are not present in each pool, and thus cannot serve as landmarks anymore. The image analysis of such gels and especially the matching of spots is not reliable under these circumstances. In order to achieve reliable matching, additional samples were created, such that pools were co-electrophoresed according to a special concatenation scheme; these samples then contained over-lapping elements (e.g., pools 1 + 2 + 3 and 3 + 4 + 5 have at least those spots in common, which originate from pool 3). This approach turned out to be feasible and we have completed the matching of one half of the ordered library. Already from the present stage of analysis we have obtained valuable information on the cDNA library and on the distribution of clones in this library.

DNA, Complementary↗
PubMed1994

Use of Poisson regression and time series analysis for detecting changes over time in rates of child injury following a prevention program.

The use of two statistical methods to quantify time trends (Poisson regression and time series analysis) is illustrated in analyses of changes in child injury incidence after implementation of a community-based injury prevention program in Central Harlem, New York City. The two analytical methods are used to quantify changes in the rate of injury following the program, while taking into account the underlying annual and seasonal trends. Rates of severe injury during the period from 1983 to 1991 among children under the age of 17 years living in Central Harlem and in the neighboring community of Washington Heights are analyzed. The two methods provide similar point estimates of the effect of the intervention and have a good fit to the data. Although time series analysis has been promoted as the method of choice in analysis of sequential observations over long periods of time, this illustration suggests that Poisson regression is an attractive and viable alternative. Poisson regression provides a versatile analytical method for quantifying the time trends of relatively rare discrete outcomes, such as severe injuries, and provides a useful tool for epidemiologists involved with program evaluation.

Accidents↗
PubMed1994

The amino acid composition of 350 lymphocyte proteins.

We determined the amino acid composition of proteins of Sp2 hybridoma cells by a procedure which assembles the information on the polypeptides upon two-dimensional gel electrophoresis, such that biosynthetic labeling with 20 different 3H amino acids provides the data--spot intensities--on the relative representation of the detected polypeptides. The gels were impregnated with 2,5-diphenyloxazol (PPO) and suitably exposed radiofluorographs were selected for analysis. The images originating from the 12 cultures labeled with amino acids R, A, H, I, L, K, M, F, P, S, T and Y were analysed with the Kepler image analysis system. The spot volume data of the 12 analysed patterns were corrected for the unequal labeling efficiencies of the 3H amino acids and for the various exposure times. This correction is performed by applying calibration factors based on the amino acid determination of a hydrolysate of the analysed cells. After the calibration step was applied to the data files we used the amino acid compositions of nine proteins taken from a database to establish for each of these proteins the correlation coefficients with the image analysis derived amino acid compositions of all spots. The correlation coefficients allow us to tentatively identify polypeptide spots on two-dimensional gels, while the amino acid composition of 350 investigated two-dimensional gel spots is usable as an identification tag in the gene retrieval from our cDNA libraries.

Amino Acids↗
PubMed1994

Participation of the school community in AIDS education: an evaluation of a high school programme in South Africa.

An AIDS education programme was developed and evaluated in a high school in a socio-economically disadvantaged, urban, African area in South Africa. The programme, which addressed the whole school community, aimed to raise awareness about AIDS using a variety of educational methods and operating through a number of channels. Students and teachers were actively involved in its design and implementation. Students' knowledge of and attitudes towards AIDS prevention were investigated before and after the AIDS programme, and compared to a neighbouring school, in which no AIDS education was conducted. The programme greatly improved student knowledge of HIV transmission and prevention. It increased levels of acceptance of people with AIDS and had a small impact on behavioural intentions. The process of involving the school community in the design of the AIDS education programme is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1994

The impact of the Safe Kids/Healthy Neighborhoods Injury Prevention Program in Harlem, 1988 through 1991.

OBJECTIVES: This study evaluated the effectiveness of a community coalition to prevent severe injuries to children in Central Harlem, New York, NY. It was hypothesized that injury incidence rates would decline during the intervention (1989 through 1991) relative to preintervention years (1983 through 1988); that the decline would be greatest for the targeted age group (5 through 16 years) and targeted injury causes (traffic accidents, assaults, firearms, outdoor falls); and that the decline would occur in the intervention community rather than a control community. METHODS: Surveillance of injuries that result in hospitalization and/or death among children in the two communities has been under way since 1983. Data from this surveillance were used to test whether the incidence of severe injury declined during the intervention; other temporal variations were controlled by Poisson regression. RESULTS: The incidence of injury among school-aged children in central Harlem declined during the intervention. The decline was specific to the targeted age group and targeted causes. A nonspecific decline also occurred in the control community. CONCLUSIONS: The declining incidence rate in Central Harlem is consistent with a favorable program effect, but additional investigation of possible secular trend or spillover effects is needed.

Accidental Falls↗
PubMed1994

Low-income neighborhoods and the risk of severe pediatric injury: a small-area analysis in northern Manhattan.

OBJECTIVES: The purpose of this study was to investigate the relationship between socioeconomic disadvantage and the incidence of severe childhood injury. METHODS: Small-area analysis was used to examine socioeconomic risk factors for pediatric injury resulting in hospitalization or death in Northern Manhattan, New York, NY, during a 9-year period (1983 through 1991). RESULTS: The average annual incidence of all causes of severe pediatric injury was 72.5 per 10,000 children; the case-fatality rate was 2.6%. Census tract proportions of low-income households, single-parent families, non-high school graduates, and unemployment were significant predictors of risk for both unintentional and intentional injury. Among the socioeconomic factors considered, low income was the single most important predictor of all injuries; other socioeconomic variables were not independent contributors once income was included in the model. Compared with children living in areas with few low-income households, children in areas with predominantly low-income households were more than twice as likely to receive injuries from all causes and four and one half times as likely to receive assault injuries. The effect of neighborhood income disparities on injury risk persisted after race was controlled. CONCLUSIONS: These results illuminate the impact of socioeconomic disparities on child health and point to the need for injury prevention efforts targeting low-income neighborhoods.

Adolescent↗
PubMed1994

Maternal-infant HIV transmission and circumstances of delivery.

OBJECTIVES: Circumstances of delivery among children with acquired immunodeficiency syndrome (AIDS) were investigated to assess whether they were consistent with predictions that intrapartum factors affect the risk of maternal-infant human immunodeficiency virus (HIV) transmission. METHODS: Pediatric AIDS patients (maternal-infant transmission; n = 632) reported to the New York City Health Department through 1991 were compared with a series of infants born to predominantly uninfected women. For each case patient, five control subjects were selected and matched from birth certificate files. Hypothesized case-control comparisons for mode of delivery and preselected complications were tested. RESULTS: Compared with control subjects, case patients were less likely to have been delivered by cesarean section without complications (odds ratio [OR] = 0.77; 95% confidence interval [CI] = 0.59, 1.01) and more likely to have been delivered with complications, whether delivery was by cesarean section (OR = 1.54; 95% CI = 0.98, 2.43) or vaginal (OR = 1.66; 95% CI = 1.15, 2.39). CONCLUSIONS: Assuming that HIV-infected and uninfected women have comparable circumstances of delivery, conditional on sociomedical characteristics, these results suggest that intrapartum events may be associated with maternal-infant HIV transmission.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Putative invasion-specific proteins in mouse T-cell hybridomas that differ in invasive and metastatic potential.

Fusion of invasive, activated T-lymphocytes with non-invasive BW5147 T-lymphoma cells mainly yields highly invasive (HI), highly metastatic T-cell hybridomas. In addition, several non-invasive (NI), non-metastatic hybrids have been obtained, probably due to loss of involved gene(s) by chromosome segregation. Here we have compared a panel of HI and NI hybrids in a search for proteins specifically expressed by either cell type. MAbs were raised against HI hybrids, but out of more than 1,000 none bound exclusively to HI cells. Furthermore, polyclonal rat, rabbit and chicken antisera did not immunoprecipitate specific proteins from total lysates, and the expression of 18 (T-cell) surface markers did not correlate with invasiveness. These results indicated that the number of differences between HI and NI hybridomas was surprisingly small. This notion was confirmed by 2-dimensional gel electrophoresis. Among 1,000 detectable spots, we found only 2 clear-cut differences between HI and NI T-cell hybridomas, whereas multiple differences were found between individual hybrids. One protein (p130) was expressed at much higher levels by HI than by NI hybrids in this panel, whereas the other (p15) was only seen in NI hybrids. These proteins are primary candidates for a role in invasion.

Animals↗
PubMed1990

Knowledge, attitudes and beliefs about AIDS in township school students in Cape Town.

Students (N = 377) from four Cape Town township high schools were surveyed to obtain information on their knowledge of and attitudes towards the acquired immunodeficiency syndrome (AIDS), and on their sexual behaviour. The study was undertaken to provide information for planning an AIDS education intervention. Three-quarters of students reported that they had had sexual intercourse. Most students had heard of AIDS, and the majority of these knew that it was infectious. More than half of the students were confused or lacked knowledge about the modes of transmission. Two-thirds of the students believed AIDS could be prevented, but knowledge of prevention strategies was superficial. Of the sexually active students only 11.4% had ever used a condom, and of all students 39.6% stated that they would use a condom in the future. Two-thirds of the students were not aware that there is no cure for AIDS. Students did not acknowledge that AIDS could affect them directly, and attributed the problem to prostitutes and 'promiscuous' people in 36.4% of responses, and to 'white' people in 23.8% of responses. Students expressed intolerance, fear and rejection of people with AIDS, and only 6.4% would accept an affected person into their class. Almost all the students wanted AIDS education at school, and most of these requested that the school nurse facilitate this education. It is concluded that appropriate AIDS prevention education is urgently required for both high school and junior school students.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Village health-workers and GOBI-FFF. An evaluation of a rural programme.

Growth monitoring, oral rehydration, breast-feeding and immunisation--female education, family spacing and food supplementation (GOBI-FFF) are a selective package of World Health Organisation primary health care strategies recommended by UNICEF. Changes over a 1-year period in the implementation of the components of GOBI-FFF were investigated in a rural village in Ciskei to detect any changes associated with a newly modified village health-worker (VHW) programme. A baseline survey was conducted before the introduction of a modified VHW programme and a second survey took place a year later. The principles of GOBI-FFF were already familiar to and have since been increasingly practised by the community and health personnel. Breast-feeding is widespread, most carers know how to make oral rehydration solution and most children have a 'Road to Health' card and are being weighed regularly. However, malnutrition remains a major problem and the food supplementation programme is operating poorly. The high coverage of the community by the village health-workers and the clinic suggest that these two channels should be used more intensively to strengthen the GOBI-FFF programme in the area.

Breast Feeding↗
PubMed1990

Reconstruction of mandibular defects in irradiated patients.

In this prospective study, mandibular reconstruction using titanium plates was evaluated in 31 patients treated between July 1988 and January 1990. Sixteen patients had prior surgery; 13 had prior radiotherapy. In 11 patients, prior radiation and surgery had failed. Sixteen patients received postoperative radiotherapy either in standard or accelerated fractions. Twelve patients had complications of either intraoral (8), extraoral (5), or combined (1) plate exposure or fistula formation (2). Factors significantly related to complications were poor nutrition, accelerated radiation, and recurrence. Sixty-one percent of all patients healed uneventfully. When patients with complications secondary to recurrence who subsequently died were excluded, the success rate was 73%. Only one patient had an unacceptable result that produced a cosmetic and functional deformity despite secondary repair.

Adult↗
PubMed1990

Molecular analysis of genetically determined target organ abnormalities in spontaneous autoimmune thyroiditis.

We have shown in earlier studies, that the development of spontaneous autoimmune thyroiditis (SAT) in chickens of the Obese strain (OS) depends on the presence of both, two dominant genes coding for an altered immune regulation and one recessive gene responsible for the susceptibility of the target organ for the autoimmune attack. The product(s) of the latter is (are) still not known. The present study was aimed at identifying possible candidates of cellular components of the thyroid gland of OS chicken and its SAT susceptible parental Cornell C-strain (CS) by high resolution 2-dimensional (2D) gel electrophoresis. For this purpose organ cultures of the thyroid, bursa, thymus and liver were established and the synthesized polypeptides were labelled by 35S-methionine. OS and CS organs were compared with those of healthy normal White Leghorn (NWL) controls. The autoradiographs of the 2D-gels obtained from individual samples after various labelling periods were subjected to comparative analysis. We have found both quantitative and qualitative differences of polypeptide spots between OS/CS and NWL organ samples, some of them specific for the thyroid gland. Although one has to be aware that in this multidimensional analytical approach numerous, still elusive pattern differences are revealed, the thyroid specific phenomena will be further scrutinized.

Animals↗
PubMed1990

Regulation of mRNA abundance in activated T lymphocytes: identification of mRNA species affected by the inhibition of protein synthesis.

Inhibition of protein synthesis has often been observed to increase the concentration of mRNAs that encode proteins associated with the regulation of cell division. As two-dimensional gel electrophoresis permits the simultaneous monitoring of individual elements in large populations of gene products, we have used this technique to assess the effect of cycloheximide treatment on the mRNA complement of activated mouse T cells in an objective fashion. Two-dimensional gels of proteins generated by cell-free translation of mRNA from T-cell blasts display about 400 spots; only 5 of these are reproducibly enhanced by cycloheximide treatment and about 4 are diminished. The cDNA cloning vector lambda jac allows analysis of large arrays of molecular clones by cell-free expression, and we have used it in a sibling selection scheme to isolate a clone of one of the prominently induced mRNA species, which we refer to as chx1. chx1 mRNA concentration is increased by cycloheximide treatment of activated B cells, as well as T cells, and it is rapidly and transiently induced, in a cycloheximide-enhanced manner, upon serum stimulation of resting 3T3 fibroblastoid cells. The chx1 protein is hydrophilic, is slightly basic, and has patches of homology with the Jun-D gene product. The chx1 gene is remarkable in its lack of detectable introns and of strong bias against CpG dinucleotides.

Amino Acid Sequence↗
PubMed1990

Evaluation of a village health worker programme: the use of village health worker retained records.

A village health worker (VHW) programme in a rural area in South Africa is evaluated, a year after the introduction of VHW-retained child record cards. The programme's success in promoting immunization and breastfeeding and the coverage of and contact with the community by the VHWs was investigated. A population survey on children under one year was matched to VHW records, showing that VHWs were reaching 70.8% of the target population. VHWs were more likely to visit a child with a Road to Health Card (RTHC) and who was born in the village. VHWs generally visit mothers once a month and make contact with most children in their first month of life. Children born before the start of the new VHW programme were compared with those born after, using survival analysis techniques and data from the RTHC on the first year of life of all children under two. An increase in polio immunization coverage was detected but there was a drop in measles immunization coverage. We conclude that a VHW-retained child record for the first year of life plays a valuable role in ongoing health care evaluation.

Breast Feeding↗
PubMed1990

Polyoma-induced thymic epithelial tumors: analysis by 2D gel electrophoresis of tumors upon labeling the entire tumor bearing host.

Injection of neonatal C3H/Bi mice with polyoma virus (PTA-5) results after 4 to 20 weeks in the development of thymic epithelial tumors in 2/3 of the mice. These tumors appear to be the result of a neoplastic proliferation or transformation of thymic epithelial cells. The tumors contain immature lymphoid infiltrates characteristic of normal tissue and express the same function as normal tissue by providing the microenvironment for T cell maturation. To establish more comprehensively the relation of neoplastic to normal thymic epithelial cells, tumor-bearing mice and their normal counterparts were labeled in vivo by injection of S35-L-methionine. The stroma and lymphoid cells were separated and analyzed by two dimensional gel electrophoresis followed by radiofluorography. It was found that the epithelial portion of the tumor differed in several structural polypeptide components from normal tissue while the polypeptide composition of the thymocyte population remained unaltered. It was concluded that the neoplasia is confined to the epithelium compartment and the function of the neoplastic organ is maintained.

Animals↗