Biomedical subjects

A Haugen

Publications and source records attributed to A Haugen.

111 records · Page 7Linked to original sources

PubMedDate not supplied

Hras1 VNTR alleles as susceptibility markers for lung cancer: relationship to microsatellite instability in tumors.

PURPOSE: To further evaluate lung cancer risk associated with rare Hras1 VNTR alleles and possible biological mechanisms. MATERIALS AND METHODS: The Hras1 VNTR was genotyped in 295 lung cancer patients and 500 healthy controls by PCR and high resolution electrophoresis. Microsatellite alterations were examined in 168 tumors by PCR and capillary electrophoresis. RESULTS: 35 Hras1 VNTR alleles were found, of which 24 were defined as rare. A relative risk of 3.3 (95% CI; 1.9-6.0) associated with rare alleles was obtained using the total groups. Increased risk was significant both for males and females. When a matched control group was used, a relative risk of 12.7 (95% CI; 1.7-93.9) was calculated for individuals with rare alleles at the Hras1 VNTR locus. A low frequency of microsatellite alterations was observed (4.7%) in lung tumors. The frequency of altered microsatellite loci was higher among patients with rare Hras1 VNTR alleles than among patients with common alleles. CONCLUSION: Rare Hras1 VNTR alleles are associated with lung cancer risk, and a genetic mechanism which increases allelic diversity may be involved.

Adult↗

PubMedDate not supplied

Biomonitoring of genotoxic exposure of aluminium plant workers.

Humans are environmentally and occupationally exposed to polycyclic aromatic hydrocarbons (PAH). PAH's are a class of tumorigenic compounds which act through metabolic transformation to chemically reactive forms, epoxides, which covalently bind to DNA forming DNA adducts. To evaluate the genotoxic effects of PAH's, air and urine samples were analyzed for PAH. Blood samples were analyzed for benzo(a)pyrene-diol-epoxide-DNA (BPDE-DNA) adducts. New methods for analyzing DNA adducts in lymphocytes have been used to study the genotoxic effects of human exposure to carcinogens. BPDE-DNA adducts in lymphocytes have been used as internal dosimeters of exposure to PAH's and several studies have been conducted. We measured BPDE-DNA adducts in aluminium plant workers with immuno-assay and physico-chemical methods. PAH-DNA adducts were detectable to a lesser extent in subjects working in an aluminium plant compared to subjects working in a coke oven plant.

Air Pollutants, Occupational↗

PubMedDate not supplied

Heterogeneity and selection of neoplastic neurogenic rat cells in vivo and in vitro.

Analysis of chromosome numbers and flow cytometric measurements of relative DNA content have been performed on four neoplastic neurogenic rat cell lines obtained from fetal BD IX-rat brain cells exposed to N-ethyl-N-nitrosourea (EtNU) in vivo, which sequentially underwent neoplastic transformation in cell culture. In vitro, the cell lines showed varying degrees of ploidy (ranging from near-diploid to near-hexaploid values) and chromosome aberrations. When grown in vivo as solid tumours in BD IX-rats and in thymus deficient nude mice, or in intraperitoneal diffusion chambers in rats, the near diploid cell lines were stable. In the lines with higher ploidies the proportion of cells with near-diploid values increased. Upon retransfer to cell culture, the cell lines gradually changed to the original in vitro pattern. However, in some cases an elevated near-diploid fraction persisted during culture after retransfer. Despite the selection of malignant cells with different ploidy in vivo and in vitro, their ultrastructural morphology remained unchanged. Thus, in this system, near-diploid cells are favoured under conditions of in vivo growth.

Animals↗