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Biomedical subjects

J Lindsten

Publications and source records attributed to J Lindsten.

At least 19 recordsLinked to original sources

Unusual XX/XY chimerism.

Apparently identical twin boys are both XX/XY and have two populations, A1 and B, of cells in their peripheral blood. Chimerism in somatic tissue outside the blood cells can be demonstrated in only one of the twins. From analysis of chromosomes and many gene markers the mechanism of origin of the unusual twins remains unclear.

ABO Blood-Group System

An early behavioral description of a person with Turner's syndrome.

A person with Turner's syndrome was described by Dr. Charles Pears in the Philosophical Transactions of the Royal Society, London, in 1805. The description included behavioral traits of mild temperament, absence of heterosexual interests, and concern about social stigmatization. These traits are the object of current behavior genetic studies of persons with Turner's syndrome.

England

Chromosome aberrations and sister-chromatid exchange in workers in chemical laboratories and a rotoprinting factory and in children of women laboratory workers.

Cultured lymphocytes from 73 workers in chemical laboratories and the printing industry were found to have a significantly increased frequency of chromatid and isochromatid breaks, in comparison with 49 control subjects (42 adults and 7 children). An increase of the same magnitude was also found in 14 children, aged 4 days--11 yr, of 11 women laboratory workers who had worked during pregnancy. A significant correlation between age and frequency of chromosome aberrations was noted for both the exposed and control children but not for the adults. The frequency of sister-chromomatid exchange was significantly increased in 12 technicians working in laboratories performing hormone analysis. 4 children of 2 female technicians working during pregnancy also had a significnatly increased frequency of sister-chromatid exchange. The cause and biological significance of these findings are not yet known.

Adolescent

Significance of genetic factors for the plasma insulin response to glucose in healthy subjects.

The intravenous glucose tolerance and plasma insulin response to glucose infusion were analysed in a twin and family material, comprising 279 healthy subjects. The relation between the blood glucose and plasma insulin values was studied by an analysis of the principal eigenvalues. The variables obtained were corrected for sex, age and weight, and standardized with regard to mean and variance. The results showed that at least four of the variables have appreciable familial correlations, corresponding to a heritability (h2) varying between 0.38 and 0.72. These correlations could not be accounted for by common environment alone. Thus, the beta cell function in normal man, as measured by a glucose challenge test, appears to be genetically regulated.

Adolescent

DNA repair and frequency of x-ray and u.v.-light induced chromosome aberrations in leukocytes from patients with Down's syndrome.

DNA-repair and the frequency of chromosome aberration after u.v. and X-ray irradiation was studied on leukocytes from patients with Down's syndrome. The u.v.-induced DNA-repair synthesis was followed by the incorporation of [3H]thymidine in the presence of hydroxyurea. Similar dose-response curves were established for Down's syndrome leukocytes and controls. The cells from patients with Down's syndrome incorporated 70-75% of the activity of control cells at the various doses (32-196 erg/mm.2). This difference was significant for the two highest u.v.-doses (P less than 0-01). The yield of dicentric chromosomes after X-ray exposure (150 rad.) was 35% higher in Down's syndrome leukocytes than in the control cells (P less than 0-001). Combined u.v. and X-ray irradiation caused a twofold increase in the frequency of dicentric chromosomes in control cells, while the increase was only 27% in Down's syndrome leukocytes. This synergistic effect of u.v. and X-ray irradiation on the yield of dicentric chromosomes suggests that healing of X-ray and u.v.-induced DNA lesions may partly utilize the same repair enzymes. The results also indicate that DNA repair mechanisms are impaired in leukocytes from patients with Down's syndrome, which may contribute to the increased incidence of leukemia and the susceptibility to X-ray irradiation in this disorder.

Adult