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Biomedical subjects

K Berg

Publications and source records attributed to K Berg.

At least 379 records · Page 21Linked to original sources
PubMed1985

The heritability of smoking behaviour in pregnancy, and the birth weights of offspring of smoking-discordant twins.

Questionnaire information on smoking habits in pregnancy was collated in 341 monozygotic (MZ) and 321 dizygotic (DZ) female twin pair cases from a population-based Norwegian Twin Panel. In a multifactorial model, the intra-pair correlation in smoking was 0.797 (+/- 0.042) in monozygotic (MZ) and 0.443 (+/- 0.075) in dizygotic (DZ) twin pairs, indicating a substantial genetic influence on liability to smoke in pregnancy. The questionnaire information was linked with birth records in the Medical Birth Registry of Norway, and birth weights of offspring of 62 MZ and 100 DZ smoking-discordant twin pairs were studied. Offspring of smoking MZ twins weighed 127 g less than birth order matched offspring of the non-smoking co-twins. This finding is additional evidence that smoking is a direct cause of reduced birth weight in offspring.

Birth Weight↗
PubMed1985

Cell-released substances interfere with low density lipoprotein receptor determination in fibroblasts.

Low density lipoprotein (LDL) receptor activity in fibroblasts decreases with increasing cell concentration. This was found for radioligand assays at 4 degrees C and 37 degrees C. Thus, it seems that it is the binding of 125I-LDL to the LDL receptor which is the step in the LDL receptor pathway that is influenced by differences in cell concentration. The reduced binding of 125I-LDL with increasing cell concentration seems to result from a modification of 125I-LDL by fibroblasts. Binding of 125I-LDL to cell-free plastic tubes was used to study this modification of 125I-LDL. Such studies indicated that direct cell contact was not required for the modification to occur. The rapid modification of 125I-LDL (within 10 min) took place even at 4 degrees C. These findings suggest that substances released from the cell membrane interact with LDL and decrease its binding to the LDL receptor. The higher the cell concentration is, the more modification of LDL takes place. Fibroblast modified LDL has reduced electrophoretic mobility. We conclude that differences in cell concentration influence LDL receptor activity by interfering with the binding of 125I-LDL to the LDL receptors, rather than affecting the receptor number on the cells' surfaces.

Cell Count↗
PubMed1985

Bechterew's syndrome (ankylosing spondylitis). A syndrome with distinct subgroups.

The results of tests for associations among radiographic findings of the dorsolumbar spine, peripheral joints, tendon insertions and the pubic symphysis are presented. Ankylosis of sacro-iliac joints, ankylosis of apophyseal joints, bridging syndesmophytes, ossified interspinous ligament, block vertebrae, arthritis of the pubic symphysis and new bone formation of the ischium were strongly mutually associated. They probably belong to the same subgroup of disease. Such findings were negatively associated with distal peripheral joint arthritis. Mixed osteophytes, parasyndesmophytes or shining corners (anterior spondylitis) showed associations suggesting that the etiology may be mixed. A late stage of sacro-iliitis, regressive changes, characterized by narrow joint spaces without extensive ankylosis and with minimal sclerosis (grade IV sacro-iliitis) was associated with distal peripheral joints arthritis, but negatively associated with signs of ankylosing processes of the dorsolumbar spine. On the basis of the radiographic findings, distinct subgroups of AS could be identified. These results confirm our previous results of an association pattern between clinical findings. We would also recommend that the grading system of sacro-iliitis put forward by Dale be adopted, since it turned out that this grading system often distinguished between distinct subgroups of this heterogeneous condition(s).

Adult↗
PubMed1985

Factor VIII and factor IX in a twin population. Evidence for a major effect of ABO locus on factor VIII level.

In order to establish the relative importance of genetic factors on the variation in plasma concentration of coagulation factors VIII and IX, these parameters were determined in 74 monozygotic and 84 like-sexed dizygotic twin pairs. The twins belonged to two age groups: 33-39 years and 57-62 years. Factor VIII was determined as factor VIII coagulant antigen (VIIICAg) and as factor VIII-related antigen (VIIIRAg). Factor IX was determined as factor IX antigen (IXAg). A higher value for each coagulation factor was found in the older-age group compared to the younger group, whereas no difference was found between the sexes. A significant correlation was found between values for VIIIRAg and VIIICAg (r = .56). For VIIICAg, it could be demonstrated that the age effect was secondary to the age effect on VIIIRAg. The concentration of VIIICAg and VIIIRAg varied among ABO blood types, being lowest in type O individuals, higher in A2 individuals, and highest in A1 and B individuals. The effect of the ABO locus on VIIICAg was secondary to an effect on VIIIRAg. Analysis of variance revealed a significant genetic influence on the variance of VIIICAg and VIIIRAg with a heritability estimate of .57 for VIIICAg and .66 for VIIIRAg. This is in agreement with a previous hypothesis of an effect of several autosomal genes on factor VIII concentration. Thirty percent of the genetic variance of VIIIRAg was due to the effect of ABO blood type. The ABO locus is therefore a major locus for the determination of factor VIII concentration. No significant genetic effect on the variation in plasma concentration of IXAg could be detected.

ABO Blood-Group System↗
PubMed1985

A cytotoxic substance (CTS-51) produced by human buffy coat cultures stimulated by staphylococcal enterotoxin B: specificity to malignant cells and kinetics of action.

A unique cytotoxic substance (CTS-51), which is rather specific to malignant cell cultures in vitro, was found to be produced together with human immune interferon and interleukin-2 in buffy coat cultures stimulated with staphylococcal enterotoxin B. CTS-51, which is stable at 100 degrees and has a molecular weight of 8,000-10,000, was found to have biological properties distinct from those of known cytotoxic cytokines. CTS-51 was able to kill four human malignant cell lines at concentrations that did not affect normal or non-malignant cell lines. The mode of CTS-51 action was found to be cytotoxic rather than cytostatic. Several kinetic studies showed that the cell killing activity seemed to be dose-dependent, and the appearance of the activity required about 24 hr. The minimum effective exposure time of the target cells to CTS-51 also seemed to be dose-dependent.

Cell Cycle↗
PubMed1985

Biological and immunological properties of native species of human leukocyte interferon.

The successful purification of the native species of human leukocyte interferon (Hu IFN - alpha) has made it possible to perform a detailed biological immunological analysis which has been disclosed that the human interferon alpha species are represented by 13 individually separated species having molecular weights in the range of 16.6 to 33.5 kD (1-3). The stained interferon proteins were eluted individually from the gel slices and assessed for antiviral activity in the human, monkey and bovine cells, as well as for immunomodulatory effect in vitro on human lymphocytes. Interferon titrations were performed in human and in bovine cells and it was disclosed that one interferon species did not have any activity in the human system, at all (2). In contrast to the human activity, the bovine activity in each Hu IFN - alpha species increased along with decreasing molecular weights. Based on equal amounts of human interferon units, the "immunological efficacy" of the 13 different human IFN alpha species yielded the following in cellular immune systems (4): 1) potentiation of the natural killer cell (NK) function was a property of all species, although the two lower species (16.6 kD and 16.9 kD) were clearly less efficient having "titers" in the NK system reduced 25-fold; 2) enhanced expression of HLA on lymphocyte membranes was induced by all of the Hu IFN alpha species to the same extent; and, 3) addition of interferon to mixed lymphocyte reaction (MLR) augmented the cytotoxic mediated lympholysis (CML) outcome of the cultures. In this system all 13 species exerted their effort equally well.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Increase in the ratio of serum levels of apolipoproteins A-I and A-II during prolonged physical strain and calorie deficiency.

Effects of four days of intense physical activity on serum concentrations of total triglycerides, total cholesterol and apolipoproteins A-I, A-II, and B were studied in 35 well-trained young men. Serum total triglyceride levels decreased to 70% of baseline levels after 24 h, and fell further to 50% of baseline levels after 4 days. Serum levels of total cholesterol fell steadily to about 80% of baseline levels on the 4th day. Apo-B levels fell to 85% of baseline levels after 24 h, and remained at that level. Apo A-I fell to about 90%, and apo A-II to about 80% of baseline levels, causing a significant increase in the ratio of apo A-I to apo A-II. The intraindividual changes in apo B were positively correlated to changes in cholesterol during the first day (r = 0.60). The changes in apo A-I and apo A-II had no significant correlation with changes in total cholesterol or triglycerides, or with one another, suggesting that apo A-I and apo A-II are metabolized independently during conditions of hard physical exercise.

Adult↗
PubMed1984

The use of polymorphic DNA and protein markers for the third complement component for determining linkage of familial hypercholesterolaemia.

We have used DNA and protein polymorphisms for the third complement component (C3) to assess the potential of DNA markers in the diagnosis and study of familial hypercholesterolaemia (FH), and to confirm the reported linkage between FH and C3. The inheritance of FH and the C3 gene has been studied in 10 families by combining information from both the protein and DNA polymorphisms. Our results confirm that the C3 gene is loosely linked to the gene causing FH (lod score maximum of 2.0) at a recombination distance of 0.15. When these results are combined with previously published data the overall lod score maximum is 4.75 at a recombination distance of 0.2, meaning that the two genes will be inherited together in only about 80% of children. These results confirm that the gene that causes familial hypercholesterolaemia is linked to C3 and is therefore on chromosome 19, but C3 is not close enough to be used as a diagnostic marker.

Adolescent↗