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Biomedical subjects

K Lange

Publications and source records attributed to K Lange.

At least 217 records · Page 12Linked to original sources
PubMed1977

Glucose metabolism in C-1300 neuroblastoma cells after inhibition of hexose monophosphate pathway.

1. Application of 6-AN (0.01 mg/ml) leads to a strong accumulation of 6-PG in C-1300 neuroblastoma cells which, however, only amounts to one third of that found in C-6 glial cells. 2. In C-1300 neuroblastoma cells dephosphorylation of the accumulated 6-PG causes a rise of the intracellular gluconate to eight times the value found for 6-PG. It is four times higher than the gluconate content observed in C-6 glial cells. 3. Although 6-PG is a competitive inhibitor of PGI it causes no reduction of glycolytic flux and ATP content in stationary phase C-1300 neuroblastoma cells in contrast to the strong reduction of glycolytic flux and ATP content observed in C-glial cells. 4. The intracellular Glc-6-P and Fru-6-P content of C-1300 neuroblastoma cells increases by four to five times after treatment with 6-AN. Both this increase and the decrease of Fru-1,6-P2 content point to an inhibition of the phosphofructokinase. 5. In contrast to C-6 glial cells no morphological changes could be observed in C-1300 neuroblastoma cells up to 24 h after administration of 6-AN.

6-Aminonicotinamide↗
PubMed1977

Estimation of the variance components for dermal ridge count.

Refinements of the scoring algorithm to estimate variance components from pedigree data are developed. Subsequent to these modifications, heritability estimates were readily obtained from data for over 50 traits, including total finger ridge count reported here. A significant contribution to the total variance of ridge count could be attributed to the effects of dominance, a finding not previously reported for this dermatoglyphic trait.

Analysis of Variance↗
PubMed1977

Cellular immunity in systemic lupus erythematosus as evidenced in vitro by leucocyte migration inhibition tests.

A leucocyte migration inhibition test was performed on 26 patients with systemic lupus erythematosus (SLE) and on 35 control subjects using three different antigens, fetal calf thymus DNA, baker's yeast RNA, and calf thymus extractable nuclear antigen (ENA). Leucocyte migration was inhibited by DNA in 17 out of 26 SLE patients (65-3%), and in only 2 of the 35 controls (5-7%). When RNA or ENA was added none of the patients or controls showed inhibition. In SLE patients migration inhibition by DNA was significantly correlated with the presence of proteinuria and/or granular casts in urinary sediment. When the migration inhibition test was positive, immunofluorescence verified active histology of the glomeruli obtained by a percutaneous renal biopsy.

Adult↗
PubMed1976

Glycolysis and glycogen metabolism after inhibition of hexose monophosphate pathway in C6-GLIAL cells.

1. 6-Aminonicotinamide (0.01 mg/ml) leads to a strong accumulation of 6-PG in C6 glial cells after 24h. 2. The accumulated 6-PG is dephosphorylated to gluconate which easily permeates the cell membrane. Extracellular gluconate is formed at a rate of 12% of the total glucose consumption. 3. 6-PG as competitive inhibitor of the PG1 caused a reduction of the glycolytic flux of about 40%. 4. The reduced glycolytic flux lowers the ATP concentration under anaerobic conditions to 75% of the controls. 5. The glycogen content after 6-AN is increased by 50%, probably by the activation of the glycogen synthetase due to the higher Glc 6-P concentration. 6. The fibroblast-like morphology of the C6 cell line has typically changed under 6-aminonicotinamide.

6-Aminonicotinamide↗
PubMed1976

Extensions to pedigree analysis. III. Variance components by the scoring method.

The classic variance components for simple polygenic traits - additive, dominance, and environmental variance - have traditionally been estimated from sample covariances between first-degree relatives. If data is gathered on pedigrees, this statistical procedure wastes information. Recently Elston & Stewart suggested an alternative likelihood procedure that uses all the information in a set of pedigrees. A refinement of their method based on the scoring technique gives rapidly converging maximum likelihood estimates of the variance components and of the male and female means. Tests of statistical hypotheses about the various parameters can then be made by the likelihood ratio method. Furthermore, using classical regression analysis, the estimated parameter values allow prediction of unknown trait values from known trait values within a pedigree. These methods should apply to traits like total finger ridge count and to quantitative measurements associated with disease traits. Since the model postulates independent environmental effects and no assortative mating, its utility in human behaviour genetics seems limited.

Female↗
PubMed1976

The genotypic distribution of relatives of homozygotes when consanguinity is present.

A correction is made to an expression given by Jacquard (1968, 1972a,b) for the genotypic distribution of a relative of a given homozygote when consanguinity is present. The correction will necessarily be small either if the allele present in the given homozygote has a frequency of near unity, or if the coefficient of inbreeding of the given homozygote is small.

Alleles↗
PubMed1976

Estimation of polygenic recurrence risk for cleft lip and palate.

Data on cleft lip with or without cleft palate are utilized to evaluate a new method for estimating recurrence risk under the polygenic threshold model. The influence of critical factors on the accuracy of the estimated risks are evaluated. The model is relatively sensitive to the estimate of heritability employed and relatively robust to the population prevalence estimate and to family size. The calculated risks for cleft lip with or without cleft palate are contrasted with the empiric figures from studies on Caucasians and Japanese populations.

Cleft Lip↗
PubMed1976

Application of the lod method to the detection of linkage between a quantitative trait and a qualitative marker: a simulation experiment.

Simulation experiments were performed to assess the power of the lod method for detecting linkage between a quantitative trait and a qualitative marker. Using family data on the Amy2-Duffy linkage, it was found that linkage detection is feasible in certain limited circumstances. The same qualitative data yielded no evidence for a significant difference in male and female recombination fractions.

Amylases↗
PubMed1976

Epidemic glomerulonephritis in Maracaibo. Evidence for progression to chronicity.

In 1968 an outbreak of 348 cases of acute poststreptococcal glomerulonephritis (AGN) was observed in Maracaibo, Venezuela. During the year, the epidemic had three peaks of incidence. Districts with better sanitation showed a lower incidence of disease than those with less adequate facilities. Endemic cases occur every year. Lowering of serum complement activity was observed in 96% and hypertension in 90% of the patients. The mortality rate in the acute phase during the epidemic was 1.31%. A history of antecedent infection was found in 39% of the cases. 70% of these infections were in the upper respiratory tract. During 1973-74, 120 of the patients (19 adults and 101 children) were reexamined. All but one had been completely asymptomatic. Sixteen patients (13.3%) had one or more of the following abnormalities (group A): low CCr, microscopic hematuria, proteinuria of 1 g/day or more and hypertension. One hundred and four patients (86.7%) were normal by all clinical and laboratory parameters tested (group B). The incidence of persisting disease, as judged by biochemical findings, was significantly higher (P less than .01) in adults (36.7%) than in children (8.9%). Percutaneous renal biopsies from 7 patients of group A, and 8 patients from group B, were studied by light microscopy and immune histology. All biopsies from group A patients had evidence of advanced glomerular disease by light microscopy and by immune histology. Seven biopsies from group B patients were also abnormal showing mild changes with corresponding immunologic findings. Only in one patient was the biopsy completely normal. Our studies indicate that significant numbers of patients progress towards chronicity after epidemic, poststreptococcal AGN. Such progression is more common in adults than in children.

Adolescent↗
PubMed1976

A hitherto unknown streptococcal antigen and its probable relation to acute poststreptococcal glomerulonephritis.

In the initial phase of acute poststreptococcal glomerulonephritis (AGN), antigenic sites not covered by specific antibody can be demonstrated in the glomeruli. These sites are on the endothelial side of the glomerular basement membrane and in the mesangial matrix. The antigen is contained in a water-soluble fraction of nephritogenic streptococci. It can be highly purified by column chromatography or acrylamide electrophoresis. This antigen against which the patient develops specific antibodies is contained and immunologically identical in all nephriotogenic streptococci examined so far irrespective of their M or T protein. It is not identical with any known streptococcal extracellular product. When antibodies are produced in rabbits against this streptococcal antigen they localize on kidney biopsies, obtained early during the disease from patients with AGN in an identical way as does the labelled antibody of the serum of patients wiht AGN. This antigen may be suited as a vaccine for the prevention of AGN.

Acute Disease↗
PubMed1975

The prior probability of autosomal linkage.

An expression is derived for the prior probability of linkage between a random trait locus and any one of m random marker loci, and this probability is computed form=1, 10, 20, 30, 50 and 100. A similar expression is derived for two trait loci, and computed for m=1, 10, 20 and 30. When one trait locus and 30 marker loci are being studied, a priori there is over a three-quarter probability that the trait locus should be syntenic with at least one of the markers, and about a one-half probability that there should be a linkage mappable from recombination frequencies. If two traits are studied, then the prior probability that at least one should be syntenic with one of the 30 markers is 0-94, and there is a three-quarter probability that such a linkage should be mappable.

Chromosome Mapping↗