DNA haplotyping of PI Z and M alleles within the German population.
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Biomedical subjects
Publications and source records attributed to K Olek.
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A partial gene deletion of about 1700 to 2000 bases spanning exon 3 and part of IVS-3 was identified in one patient with severe haemophilia A. Extensive DNA analysis of his family members revealed that the mother of the proband is a somatic mosaic for an abnormal factor VIII gene, because the defective gene could be identified in a considerable fraction of the leucocytes as well as of the cultured fibroblasts of the mother. This observation is important in estimating the recurrence risk in families of sporadic cases.
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Two hundred and thirty five subjects from 48 German cystic fibrosis (CF) families were typed for restriction fragment length polymorphisms (RFLPs) detected by the probes pmet H, pmet D, and pJ 3.11, known to be tightly linked to the CF gene. Gene and haplotype frequencies suggest a linkage disequilibrium with the CF locus. The analysis of the predictive value of this typing in individual CF families indicates that the combined use of these probes provides a powerful diagnostic system both for carrier detection and prenatal diagnosis. In 33 out of 48 families carriers and non-carriers could be identified, and in 26 of these 33 families prenatal diagnosis could discriminate between affected and unaffected offspring.
DNA-fragments from the region of the long arm of human chromosome 7 to which the CF-locus has been mapped recently were isolated by microdissection and microcloning. We developed a new fixation procedure resulting in inserts of 1.0-7.0 kb in length with a mean value of 2.9 kb. Regional mapping of three clones on 7q was carried out by the use of different hybrid cell lines containing fragments of human chromosome 7.
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A grid of damaged areas was introduced into serum-starved BALB/c-3T3 fibroblast monolayers. The expression of c-fos specific messenger RNA was examined by the use of the cytoplasmic dot hybridisation technique 15, 30 and 45 min after wounding. The expression of c-fos messenger RNA was highest after 30 min, while microglobulin was constantly expressed. These results show that the unspecific event of wounding induces the specific expression of c-fos messenger RNA, an effect similar to that of growth factors during serum stimulation.
We have used a panel of eight human/mouse somatic-cell hybrids, each containing various portions of human chromosome 7, and three patient cell lines with interstitial deletions on chromosome 7 for localization of six DNA markers linked to the cystic fibrosis locus. Our data suggest that D7S15 is located in the region 7 cen----q22, that MET is located in 7q22----31, and that D7S8 and 7C22 are located in q22----q32. The hybridization results for COL1A2 and TCRB are consistent with their previous assignment to 7q21----q22 and 7q32, respectively. Given the location of these six markers and their linkage relationships, it is probable that the cystic fibrosis locus is in either the distal region of band q22 or the proximal region of q31. Using the same set of cell lines, we have also examined the location of another chromosome 7 marker PGY1. The data show that PGY1 is located in the region 7cen----q22, a position very different from its previous assignment.
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Free and conjugated GABA concentrations were measured in CSF and plasma from 28 patients with manifest Huntington's chorea (HC) and 30 age- and sex-matched controls. GABA was determined by ion-exchange chromatography with fluorimetric detection (IE/F). Free and conjugated CSF GABA was significantly decreased in prolonged HC with advanced disease states and was suggested practicable as an additional diagnostic tool. However, in younger patients (less than 40 yrs) with a short period of HC (less than 2 yrs) an overlap with the age-matched normal range indicated GABA measurement inadequate to early diagnosis nor predictive for offspring at risk. An age-dependent decrease of conjugated CSF GABA was observed in patients and controls. The more pronounced decrease in patients might reflect the neurodegenerative feature of HC.
A rapid and sensitive procedure is described for the quantification of gamma-aminobutyric acid in human plasma, using ion-exchange fluorescence. Analytical values for gamma-aminobutyric acid vary according to the method of deproteinization, storage conditions and sample treatment. A practicable and precise method for the evaluation of free and bound gamma-aminobutyric acid is presented. The mean concentration of the free neurotransmitter in neurologically normal control subjects was 142.4 +/- 13.1 nmol/l (n = 30). The mean concentration of the bound form was 438.6 +/- 51.1 nmol/l in the same subgroup.
Three children with hyperphenylalaninaemia and hyperphenylalaninaemic mothers are presented. At least one of the affected children was a compound heterozygote for hyperphenylalaninaemia and phenylketonuria. The families were examined by an L-phenylalanine loading test, by direct determination of phenylalanine hydroxylase and/or a loading test with hepta-deuterophenylalanine. We conclude that most of the patients with moderately elevated serum phenylalanine should have the genotype hyperphenylalaninaemia/phenylketonuria, i.e. they are compound heterozygotes.
A rapid and simple procedure is described for the determination of 4-aminobutyric acid in human CSF. The o-phthaldialdehyde derivative of 4-aminobutyric acid is analysed with a slightly modified commercially available Amino Acid Analyser. We investigated the sample preparation with special emphasis on the sulphosalicylic acid-induced hydrolysis of 4-aminobutyric acid containing compounds in human liquor. Our experiments demonstrate that the amount of estimated 4-aminobutyric acid depends considerably on the sulphosalicylic acid concentration used for protein precipitation. Application of ultrafiltration instead of sulphosalicylic acid precipitation resulted in markedly decreased 4-aminobutyric acid values. By first using ultrafiltration and by minimizing the time between lumbar puncture and analysis, it was shown that protein precipitation with a concentration of sulphosalicylic acid as low as 5 g/l gives 4-aminobutyric acid values in CSF that are essentially correct.