Biomedical subjects
Publications and source records attributed to R Brdicka.
Reflections on old and new ethical problems of medical genetics stimulated by new diagnostic possibilities and needs which should stimulate reflections of the largest possible number of doctors as well as lawyers and all those who ought to take a stand in the matter.
New findings on the possible application of DNA diagnosis in the prevention of hereditary diseases are associated also with ethical problems of medical genetics. A questionnaire programme evaluated the views of respondents (743) on four groups of questions: 1. state of information on health status, 2. examination of members of the family, 3. compulsory treatment, 4. preventive measures. The authors sought mutual associations between the replies to individual questions and characteristics of respondents. Development of medicine calls for interdisciplinary health education and the solution of newly arisen ethical and legal problems.
The authors compared two at present most widely used techniques for labelling DNA probes: a) radioactive labelling by means of the radioisotope 32P; non-radioactive labelling using the hapten digoxigenin for the visualization of the hybridization process on nylon membranes. Then sensitivity of the technique of non-radioactive labelling of heterochromatin probes was equivalent to the radioactive method.
The author tested the method of DNA fingerprinting on DNA of blood donors. The results indicate that the method could be introduced in forensic practice and used as a routine procedure.
DNA haplotype data from the phenylalanine hydroxylase (PAH) locus are available from a number of European populations as a result of RFLP testing for genetic counseling in families with phenylketonuria (PKU). We have analyzed data from Hungary and Czechoslovakia together with published data from five additional countries--Denmark, Switzerland, Scotland, Germany, and France--representing a broad geographic and ethnographic range. The data include 686 complete chromosomal haplotypes for eight RFLP sites assayed in 202 unrelated Caucasian families with PKU. Forty-six distinct RFLP haplotypes have been observed to date, 10 unique to PKU-bearing chromosomes, 12 unique to non-PKU chromosomes, and the remainder found in association with both types. Despite the large number of haplotypes observed (still much less than the theoretical maximum of 384), five haplotypes alone account for more than 76% of normal European chromosomes and four haplotypes alone account for more than 80% of PKU-bearing chromosomes. We evaluated the distribution of haplotypes and alleles within these populations and calculated pairwise disequilibrium values between RFLP sites and between these sites and a hypothetical PKU "locus." These are statistically significant differences between European populations in the frequencies of non-PKU chromosomal haplotypes (P = .025) and PKU chromosomal haplotypes (P much less than .001). Haplotype frequencies of the PKU and non-PKU chromosomes also differ significantly (P much less than .001. Disequilibrium values are consistent with the PAH physical map and support the molecular evidence for multiple, independent PKU mutations in Caucasians. However, the data do not support a single geographic origin for these mutations.(ABSTRACT TRUNCATED AT 250 WORDS)
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About 3,500 subjects from Italy and Czechoslovakia have been analyzed by acid starch gel electrophoresis for the subtyping of PGM1 polymorphism. The Italian sample included three different subgroups, from Northern, Central and Southern Italy. The allele frequencies found in the three groups do not differ significantly from each other; the observed values in the pooled sample are: PGM1S1 = 0.594, PGM1F1 = 0.118, PGM2S1 = 0.231, PGM2F1 = 0.057. In the Czechoslovakian group, which differs significantly from the Italian population, the following allele frequencies were found: PGM1S1 = 0.639, PGM1F1 = 0.118, PGM2S1 = 0.180, PGM2F1 = 0.063. The analysis of 217 families did not show any exception to Mendelian inheritance of the patterns.
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The electrophoretic and thermostability polymorphisms of the PGM1 locus were examined in about 700 Czechoslovakians (Prague) and 3000 Italians. The Italian sample consisted of individuals from Pavia (Northern Italy), Viareggio and Rome (Central Italy) and Naples (Southern Italy). The eight PGM1 alleles, PGM1Str1, PGM1Sts1, PGM1Ftr1, PGM1Fts1, PGM2Str1, PGM2Sts1, PGM2Ftr1, PGM2Fts1, have been considered as combinations of mutations at three different sites, 1/2, S/F and tr/ts, within the PGM1 gene and their frequencies discussed in terms of linkage disequilibrium between these sites. All pairwise differences between the samples were significant except for Pavia-Viareggio and Viareggio-Rome. The frequencies of the PGMts1 alleles have been found to range from 0.0981 (Prague) to 0.0546 (Naples) and can be ordered according to a North-South cline.
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By comparing electrophoretic patterns of urinary proteins from males of different inbred strains and pertinent hybrids, a new polymorphic locus designated Mur-2 has been detected.
Incidence and onset of the IDDM were studied in progeny of different mating types and generations of the partially inbred BB/K and randombred BB/DK substrains. The first two generations of BB/K rats showed a high incidence (75-80%) of IDDM which corresponded to their relative genetic homogeneity (homozygotes for haemoglobin and esterase-1 loci). But the incidence of IDDM did not depend on the type of parental mating, probably due to residual genetic heterogeneity (for two non-RT1 antigens and three biochemical traits). The randombred BB/DK strain showed a relatively low incidence (11.4-16.7%) of IDDM, and its later onset. Mycoplasma infection lowered drastically the IDDM incidence in the 3rd generation of BB/K rats. This infection caused most probably a pronounced distortion of the segregation ratio in the (BB/K x LEW)F2 hybrids. The RT1u haplotype showed a lethal or sublethal effect in the homozygous state. The BB/K substrain became extinct in the 7th generation from mycoplasma infection. Interactions between infection and development of IDDM, its polygenic nature and role of the RT1u variant haplotype are discussed.
A review of laboratory rat strains with regard to interstrain differences in different enzyme systems and other proteins is presented. Allelic distribution of polymorphic systems is shown.