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Biomedical subjects

J Lindsten

Publications and source records attributed to J Lindsten.

At least 73 records · Page 4Linked to original sources
PubMed1977

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↗
PubMed1977

Carcinoembryonic antigen in amniotic fluid.

Carcinoembryonic antigen (CEA), a substance which is known to occur in high amounts in the fetal gut and also in certain tumors of the gastrointestinal tract, has been demonstrated in amniotic fluids from different stages of pregnancy. Radioimmunoassays of CEA in amniotic fluids of 91 normal pregnancies showed a decrease from a mean of 53 ng/ml at 19 weeks to 25 ng/ml at the end of gestation. The CEA activity in amniotic fluid was eluted in the same volume as a standard 125I-CEA on a Sephadex G200 column. Amniotic fluid therefore contains CEA similar in molecular weight to the CEA purified from liver metastases of colonic cancer. Among 17 cases of abnormal pregnancies, CEA elevations were observed in five with anomalous fetuses.

Amniotic Fluid↗
PubMed1977

A chiasma map of man.

By fitting compounds beta distributions to chiasma frequencies the physical map obtained from banded chromosomes has been converted into a chiasma map giving the distribution of observed chiasmata in relation to several hundred cytological bands, assuming proportionality of mitotic and meiotic chromosomes. This is a genetic map if there is a precise correspondence between sites of chiasmata and crossing-over. However, if there is appreciable preanaphase movement of chasmata, then the chiasma map is a serious distortion of the genetic map. Predictions from the chiasma map can be confirmed or refuted only by genetic evidence for which the estimates of this paper serve as initial values to begin maximum likelihood iteration.

Chromosome Mapping↗
PubMed1977

A mapping function for man.

Assuming a perfect correspondence between the site of crossing-over and an observed chiasma, data on meiosis in the human male are used to estimate a mapping parameter which on average turns out to be intermediate between the Kosambi and Carter-Falconer values, but smaller for acrocentrics. A table is given for converting recombination frequencies to map distances.

Chromosome Mapping↗
PubMed1976

Molecular forms and activities of glycosidases in cultures of amniotic-fluid cells.

Ion-exchange chromatography of gel filtration demonstrated the presence of different molecular forms of nine lysosomal enzymes in cultured amniotic-fluid cells. The patterns of molecular forms were similar to those known from skin fibroblasts and liver tissue. During cultivation total enzyme activities fluctuated with the number of passages, without any consistent trend of increase or decrease, and without correlation to the dominating cell type in the culture.

Acetylglucosaminidase↗
PubMed1976

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↗
PubMed1976

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↗
PubMed1975

Alpha fetoprotein levels in maternal serum and in amniotic fluid from early normal pregnancies.

Alpha fetoprotein (AFP) was determined in serum from 241 women in the 8th to 43rd week of gestation by quantitative radioimmunoelectrophoresis, and in 103 amniotic fluid samples from the first half of pregnancy by rocket immunoelectrophoresis. Both serum and amniotic fluid samples were obtained from a larger material, but samples were included only from pregnant women whose infants were normal at birth. The 90% normal AFP range was calculated both for maternal serum and for amniotic fluid.

Alpha-Globulins↗
PubMed1975

A genetic analysis of the normal body-height growth and dental development in man.

A twin and family study on the significance of genetic factors for the variation in certain new variables of dental and body-height development is presented. Evidence of a rather strong genetic regulation of most of the variables was obtained from the analysis of the twins and sibs. The data on cousins did not allow any definite conclusions, and it was not possible to obtain a parent--offspring material. Therefore, the study did not give any information concerning the relative significance of additive genetic variation.

Adolescent↗