Biomedical subjects
Publications and source records attributed to K Berg.
Marfan Syndrome is a genetic disorder of the connective tissue. Individuals from one large family with this disorder were genotyped for COL1A2 gene associated RFLPs. Our results demonstrated that the COL1A2 gene, encoding the proa2(I) collagen chain, segregated independently of the phenotype and it is therefore excluded as the mutant locus in this family.
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The effects of 10 wk of exercise training at low (40% VO2max) or high (75% VO2max) intensity on serum lipids and lipoproteins were compared in prepubescent boys and adult men. The final sample size consisted of: 8 boys (mean +/- SE age = 8.5 +/- 1.96 yr) and 8 men (36.6 +/- 3.18 yr) in low; 12 boys (8.0 +/- 1.40 yr) and 12 men (36.6 +/- 4.09 yr) in high; and 10 boys (9.0 +/- 2.08 yr) and 10 men (36.7 +/- 4.82 yr) in control. Training involved walking/jogging/running 3 d X wk-1 at a distance which progressed from 2.4 km X d-1 in the first week to 4.8 km X d-1 from the fifth week. Fasting blood samples, collected on 2 d during both pre- and post-training, were assayed for triglycerides, total cholesterol (CHOL), and high density lipoprotein cholesterol (HDL-C). Maximum aerobic power (VO2max) was determined from a treadmill test. Additionally, dietary intake was assessed from a 3-d dietary record and body composition from the sum of 6 skinfolds. The only statistically significant (P less than 0.05) changes occurred in HDL-C and CHOL for the high groups. HDL-C decreased following training. CHOL was lower for high than the other groups for the first day post-training only. There were no differences in the changes in HDL-C/CHOL ratio among the groups. VO2max only increased in the high groups. Dietary intake and body weight did not change. Further statistical adjustment in lipids for changes in sum of 6 skinfolds did not alter the results.(ABSTRACT TRUNCATED AT 250 WORDS)
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Segregation analysis of four Lp assays on 557 children in 227 families reveals a dominant major gene and a residual heritable component that may reflect one or more alleles of weaker effect. Close or moderate linkage to esterase-D (ESD) is excluded.
Two common restriction fragment length polymorphisms detected with cloned gene probes for apolipoprotein CII (apo CII) have been used to study the inheritance of the gene in families segregating for loci on chromosome 19. Lod scores for APOC2 with the gene for complement component 3 (C3) exclude close linkage and give a maximum at a male recombination fraction of 0.25-0.30. Lod scores for APOC2 and FHC, the gene causing familial hypercholesterolaemia, are negative in males and suggest the genes may not be linked. However, it appears that APOC2 may be closely linked to the blood group loci Lutheran (Lu) and Secretor (Se), and probably less closely linked to Lewis (Le). These data are consistent with the gene order: FHC-----C3-----(Lu, Se, APOC2)
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The increase in birth weight with parity was studied in sibships of 2, 3, and 4 children using large samples from the Norwegian Birth Registry. Families with full sibs were compared to families with maternal half-sibs. The sensitization hypothesis of Warburton and Naylor predicts no increase in birth weight with parity when the mother changes mate. The hypothesis was not supported by the data, since similar increases in birth weight with parity were found in both types of families. A small effect of the sex of the first child on the birth weight of the later born children was observed.
Birth weights of offspring of 105 female, monozygotic twin pairs discordant in birth weight were studied. No significant differences were found when offspring of the larger twin were compared with offspring of the smaller twin. The results do not support the hypothesis that in utero effects on females associated with low birth weight will influence their subsequent chance of having low birth weight offspring.
For 98 pairs of MZ twins, four measures indicating degree of cotwin closeness were correlated with absolute differences between IQ scores within pairs. In two different twin samples (40 MZ vs 40 DZ pairs and 169 MZ vs 174 DZ pairs, respectively), means and standard deviations in the closeness variables were obtained for MZ and DZ pairs. Whereas MZ cotwins were clearly closer than DZ cotwins, the relation between cotwin closeness and similarity in IQ seemed rather weak and ambiguous. "Years lived together in childhood home" were positively related to similarity in IQ (P less than 0.01), whereas subjective feeling of closeness in contact tended to be negatively related to similarity in IQ.
The effect of lipid lowering diet on low density lipoprotein (LDL) receptor activity has been studied in freshly isolated peripheral blood mononuclear cells (PBMCs) from 16 hypercholesterolemic male subjects during a three weeks' dietary intervention trial. The participants were randomized to an intervention group or to a control group. The subjects in the intervention group had a non-significantly larger increase in LDL receptor activity, determined as degradation of 125I-LDL at 37 degrees C, than the control group (49.7 +/- 18.1 and 35.4 +/- 21.2 ng/mg, respectively). Irrespective of assignment to the intervention group or control group, the eight subjects with the largest reduction in total serum cholesterol had significantly larger absolute and percentage increases in LDL receptor activity than the eight subjects with the smallest reduction in total serum cholesterol (p less than 0.05). Thus, it appears that the cholesterol reduction that can be achieved in humans by dietary intervention results in a small increase in LDL receptor activity in freshly isolated PBMCs.
Low density lipoprotein (LDL) receptor activity determined as association or degradation of 125I-LDL at 37 degrees C, was measured in cultured skin fibroblasts from 48 elderly, independent subjects (84-95 years old). Data concerning these subjects were compared with those from a reference group of 27 younger, healthy subjects (5-64 years old) and 23 heterozygotes for familial hypercholesterolemia (9-67 years old). The median (10th-90th percentile) association and degradation value for the older subjects were 294 (172-535) ng 125I-LDL/mg protein/6h and 191 (99-376) ng 125I-LDL/mg protein/6h, respectively. These values did not differ significantly from the corresponding values in the normal subjects (296 (60-491) ng 125I-LDL/mg protein/6h and 171 (99-275) ng 125I-LDL/mg protein/6h, respectively). Thus, maximal LDL receptor activity in fibroblasts from the older subjects seems to be comparable to that of younger, healthy controls. However, the elderly subjects had markedly higher values for total serum cholesterol and LDL cholesterol than the normal controls. There was a significant increase in LDL receptor activity with age in the normal controls. Such an increase was not found in heterozygotes for familial hypercholesterolemia.
The apoE polymorphism was studied by two-dimensional gel electrophoresis in serum samples from 62 male subjects with multifactorial hypercholesterolemia and from 63 normal subjects. The apoE-4 isoform was significantly more frequent (p less than 0.02) among the hypercholesterolemic subjects than among the normocholesterolemic controls.
Data on parental consanguinity have been recorded for all births in Norway since 1967. Pregnancy outcome for offspring of 848 women mated to their first cousins were compared with offspring of 1,696 control women. The stillbirth rate was 23.6 per thousand for cases and 13.4 for controls. The neonatal death rate was 34.9 per thousand for cases and 14.3 for controls. The recurrence risk for sibs for early death was 9.4% for cases and 4.2% for controls. The mean offspring birth weight was significantly lower (3377 g vs. 3491 g), and the variance in birth weight was slightly larger for cases than controls. The percentage of children with malformations detected shortly after birth was 4.6% for cases and 2.2% for controls. The differences may be attributed to the increased homozygosity in offspring of first cousins. The results have relevance for genetic counselling to consanguineous couples, as well as for the understanding of the etiology of adverse pregnancy outcome and for elucidating the causes of variation in birth weight.
This study was undertaken to test if the effect of lipid lowering diet on total serum cholesterol, is influenced by maximal low density lipoprotein (LDL) receptor activity. LDL receptor activity was determined in cultured skin fibroblasts from hypercholesterolemic, male subjects after lipid lowering diet intervention. The LDL receptor values from 15 subjects (responders) who had responded well to a lipid lowering diet and from 14 subjects (non-responders) who had responded poorly, were compared. The responders had a reduction in total serum cholesterol of 29.4%, and the non-responders had a reduction of 8.2% (p less than 0.0001). The higher values for LDL receptor activity among the responders did not reach statistical significance. For all 29 subjects there were non-significant positive correlations between reductions in total serum cholesterol and values for association or degradation of 125I-LDL at 37 degrees C (r = 0.16, p = 0.40 and r = 0.17, p = 0.38, respectively). Thus, it seems that maximal LDL receptor activity is not a major predictor for the response of lipid lowering diet on total serum cholesterol levels in hypercholesterolemic subjects without autosomal dominant familial hypercholesterolemia.
Restriction fragment length polymorphisms detectable with the RC8 probe, a probe for an area located on the short arm of the X-chromosome, and loosely linked to the locus for Duchenne muscular dystrophy, have been studied in a Norwegian population. With the TaqI enzyme three variants were observed. The gene frequencies of the previously detected variants were 0.867 and 0.082, respectively, and the frequency of a new variant was 0.051. Family studies confirmed Mendelian inheritance of the variants.
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