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Biomedical subjects

F Vogel

Publications and source records attributed to F Vogel.

At least 19 recordsLinked to original sources
PubMed1992

Risk calculations for hereditary effects of ionizing radiation in humans.

A prediction of the extent to which an additional dose of ionizing radiation increases the natural germ cell mutation rate, and how much such an increase will affect the health status of future human populations is part of the service that human geneticists are expected to offer to human society. However, more detailed scrutiny of the difficulties involved reveals an extremely complex set of problems. A large number of questions arises before such a prediction can be given with confidence; many such questions cannot be answered at our present state of knowledge. However, such predictions have recently been attempted. The 1988 report of the United Nations Scientific Committee for the Effects of Atomic Radiation and the fifth report of the Committee on Biological Effects of Ionizing Radiation of the US National Research Council have presented a discussion of the human genetics problems involved. Empirical data from studies on children of highly radiation-exposed parents, e.g. parents exposed to the atomic bombs of Hiroshima and Nagasaki, or parents belonging to populations living on soil with high background radiation, have been mentioned in this context. Whereas precise predictions are impossible as yet because of deficiencies in our knowledge of medical genetics at various levels, the bulk of the existing evidence points to only small effects of low or moderate radiation doses, effects that will probably be buried in the "background noise" of changing patterns of human morbidity and mortality.

Abnormalities, Radiation-Induced↗
PubMed1992

Localization of a gene for the human low-voltage EEG on 20q and genetic heterogeneity.

The localization of a gene responsible for a normal variant of the human electroencephalogram to the distal part of chromosome 20q is reported. A linkage analysis, including 17 families with 191 individuals, tested with 73 RFLPs and 22 blood and serological markers, was performed for the low-voltage electroencephalogram. This is a normal variant of the human electroencephalogram with an autosomal dominant mode of inheritance. The results present strong evidence for close linkage with the highly polymorphic marker CMM6 (D20S19) and for genetic heterogeneity.

Chromosomes, Human, Pair 20↗
PubMed1992

D20S19, linked to low voltage EEG, benign neonatal convulsions, and Fanconi anaemia, maps to a region of enhanced recombination and is localized between CpG islands.

Recent linkage studies located genes responsible for the low voltage EEG, benign neonatal convulsions and for the Fanconi anaemia to the vicinity of the VNTR marker CMM6 (D20S19). Physical mapping experiments using pulsefield electrophoresis in the distal part of chromosome 20q were chosen as a first step towards cloning of these genes. The observed pattern of shared fragments lead to the locus order 'tel-IP20K09-RMR6-CMM6-MS214-cen', which differs from previously reported genetic linkage maps. The physical intervals between these probes are markedly shorter compared with the genetic distances. Clusters of rare cutter sites around CMM6 point to at least four closely related CpG islands.

Base Sequence↗
PubMed1992

Ring chromosome 13: lack of distinct syndromes based on different breakpoints on 13q.

A stillborn male child with anencephaly and multiple malformations was found to have the karyotype 46,XY,r(13) (p11q21.1). The breakpoint at 13q21.1, determined by high resolution banding, is the most proximal breakpoint ever reported in patients with ring chromosome 13. In situ hybridisation with the probe L1.26 confirmed the derivation from chromosome 13 and DNA polymorphism analysis showed maternal origin of the ring chromosome. Our results, together with a review of previous reports of cases with ring chromosome 13 with identified breakpoints, could neither support the theory of distinct clinical syndromes based on different breakpoints on 13q nor correlate the severity of symptoms with instability of the ring.

Abnormalities, Multiple↗
PubMed1992

Immunocytochemical localization of alkane-inducible cytochrome P-450 and its NADPH-dependent reductase in the yeast Candida maltosa.

Antibodies directed against cytochrome P-450Cm1 and the NADPH-cytochrome P-450 reductase were used to study the induction and intracellular localization of these components of the alkane monooxygenase system in the yeast Candida maltosa. Transition from glucose to n-hexadecane utilization resulted in an about 100-fold increase of the immunodetectable P-450 form whereas the reductase was only moderately induced by a factor of about 5. P-450 but not the reductase was further increased by oxygen limitation during cultivation on n-hexadecane. Using an immunogold technique on ultrathin cryosections, P-450 was found to be concentrated in the nuclear envelope during the early phase of the induction process. However, after maximal induction, the highest labeling was observed in membranes of the endoplasmic reticulum closely associated with the peroxisomes and the plasma membrane. Double-labeling experiments revealed that P-450 and its reductase were distributed in the same regions of the endoplasmic reticulum.

Alkanes↗
PubMed1991

Tapetoretinal degeneration in brothers with apparent Cohen syndrome: nosology with Mirhosseini-Holmes-Walton syndrome.

We report on 2 brothers with marked eye anomalies, documented with histopathological studies, and several other findings fitting the diagnosis of both the Cohen and the Mirhosseini-Holmes-Walton syndromes. In accordance with Norio and Raitta (Norio R, Raitta C (1986): Am J Med Genet 25:397-398) we come to the conclusion that these 2 syndromes constitute one clinical but possibly heterogeneous entity.

Abnormalities, Multiple↗
PubMed1991

The use of oral temafloxacin compared with a parenteral cephalosporin in hospitalized patients with pneumonia.

In a European open, multicentre, prospective clinical trial, 100 hospitalized adult patients (61 males; 18-91 years old (mean age 62] with bacterial pneumonia, diagnosed clinically and radiographically, were randomized to receive either oral temafloxacin 600 mg twice daily (n = 49) or intravenous cefotaxime 2 g thrice daily (n = 51). Signs, symptoms and chest radiographs were assessed during, at the end of therapy and at follow-up eight to ten days after the last dose. Patients were treated for a maximum of ten days. Sputum was obtained for culture before, during and after therapy. The clinical cure rate for the temafloxacin treatment group was 90%, the bacteriological cure rate was 91% and the radiological response rate was 95%. The respective rates for the cefotaxime-treated group were 92%, 96% and 100%. There were no significant differences between the treatment groups for clinical or microbiological outcome, premature study discontinuation, or adverse events. Oral temafloxacin was clinically and bacteriologically equivalent to intravenous cefotaxime in the treatment of hospitalized adults with bacterial pneumonia.

Administration, Oral↗
PubMed1991

Computer-tomographic (CT) studies and anthropological measurements in patients with atlanto-occipital fusion.

Computer tomographic (CT) studies and anthropological measurements were performed in individuals showing complete or partial atlanto-occipital fusion. In 13 patients and 13 matched controls all measurements excepting head length and head breadth gave smaller, and in some instances significantly smaller values in the patients. The two head measurements, on the other hand, turned out to be somewhat, though not significantly larger. This suggested a certain amount of hydrocephalus internus. Computer-tomographic (CT) studies in 11 patients and 9 controls gave some--not very clearcut--evidence in favor of this hypothesis. Moreover, some other mild anomalies such as prominent and dilated sulci and cisterns were observed in 9 of 11 patients and in 3 of 9 controls (P1 one tailed = 0.0399).

Adolescent↗
PubMed1991

Comparison of two cytochromes P-450 from Candida maltosa: primary structures, substrate specificities and effects of their expression in Saccharomyces cerevisiae on the proliferation of the endoplasmic reticulum.

cDNAs were cloned, sequenced and expressed which encode two different cytochrome P-450 forms of the alkane-assimilating yeast Candida maltosa, designated as P-450Cm1 and P-450Cm2. The amino acid sequences deduced were about 55% identical. Expression in Saccharomyces cerevisiae resulted in the formation of intact microsomal P-450 systems catalyzing the hydroxylation of n-hexadecane and lauric acid with significantly different substrate preferences. A massive proliferation of the endoplasmic reticulum was observed in the S. cerevisiae cells which produced P-450. Depending on the P-450 form expressed, distinctly organized stacks of paired membranes appeared and occupied considerable areas of the cytoplasm. As shown by immunoelectron microscopy for P-450Cm1, the protein expressed was highly concentrated within these newly formed membrane structures.

Amino Acid Sequence↗
PubMed1990

Selective advantage of fra (X) heterozygotes.

The high incidence of the fra (X) syndrome (about 1:2000 male newborns) requires an explanation in view of the low fitness of mentally retarded hemizygous males and heterozygous females. In the past, it has been proposed that the mutation rate may be unusually high, and that mutations occur exclusively in male germ cells. According to an alternative hypothesis, a moderately high mutation rate might combine with a selective advantage of clinically unaffected heterozygotes. In earlier studies, such a combined hypothesis was shown to lead to plausible implications regarding mutation rate and fitness. Moreover, a mutation rate in male germ cells of the magnitude required by the exclusive mutation hypothesis was excluded by studies on comprehensive pedigree data. In this third study in the series, an increased fitness of heterozygous females is demonstrated directly by a comparison of the reproductive performance of heterozygotes with that of adequate controls (mothers and grandparents of Down's syndrome patients). Since, average numbers of children have decreased during recent decades in populations of industrialized countries, heterozygotes (mothers of affected probands and their female relatives in their own generation) were subdivided into those born before and after 1940. Moreover, sibship sizes of probands' mothers and fathers were analyzed separately for family branches in which the fra (X) trait segregated (mostly the maternal branch), or did not segregate (in most instances the paternal branch). In all four categories reproductive performance in heterozygotes was found to be higher than in the controls. This difference was significant statistically for two of the four groups; it was small and nonsignificant only for the parental family branch in which the fra (X) mutant did not segregate and for mothers born after 1940. Fitness estimates ranged between 1.11 and 1.36. A higher incidence of dizygotic twinning suggests a biological component for this increased fertility. On the other hand, fra (X) families have a significantly lower social status than the controls. This suggests a socio-psychological component of their higher fertility. Apparently, both components contribute to their fertility; at present, their relative importance cannot be assessed.

Birth Rate↗
PubMed1990

Developmental regulation of mammary-derived growth inhibitor expression in bovine mammary tissue.

The cDNA for a previously described growth inhibitor, designated as mammary-derived growth inhibitor (MDGI) (Grosse, R., and P. Langen. 1989. In Handbook of Experimental Pharmacology. In press) has been cloned from a plasmid library which was derived from terminally differentiated bovine mammary gland. Sequencing of the cDNA showed an open reading frame coding for a protein of 133 amino acids. In six positions differences were found between the sequence determined from the cDNA and that determined previously by amino acid sequence analysis. Northern blot analysis revealed abundant MDGI mRNA in the terminally differentiated mammary gland, whereas in virgin gland, liver or pancreas transcripts were not expressed. By use of in situ hybridization technique transcription of MDGI in the developing bovine mammary gland was analyzed. Increasing amounts of MDGI mRNA were detected in the epithelial cells of embryonic mammary rudiment, in the epithelium of developing lobules and in terminal parts of ducts and lobuloalveolar epithelial cells of differentiated glands. There was a geographical gradient of MDGI mRNA concentration in bovine mammary gland reaching a maximum in the proximal parts of the tissue. An immunohistochemical analysis with different polyclonal and peptide directed antibodies against MDGI confirmed the in situ hybridization data with respect to the tissue-specific and differentiation-dependent MDGI expression in bovine mammary gland. The results suggest a close relationship between MDGI transcription and developmental processes in the normal bovine mammary gland.

Amino Acid Sequence↗
PubMed1990

Segregation of the signal sequence receptor protein in the rough endoplasmic reticulum membrane.

The signal sequence receptor (SSR), an integral membrane glycoprotein of 34 kDa, has previously been shown to be a component of the molecular environment which nascent polypeptide chains meet in passage through the endoplasmic reticulum (ER) membrane. We have used antibodies directed against the SSR and both immunocytochemistry and cell fractionation to determine its distribution in rat liver cells. SSR was found largely restricted to the rough ER. Only small amounts of the protein were detected in smooth ER. These results provide further evidence for a functional differentiation of rough and smooth ER and for a role of SSR in protein translocation across the ER membrane.

Animals↗
PubMed1989

A mammary-derived growth inhibitor (MDGI) related 70 kDa antigen identified in nuclei of mammary epithelial cells.

The aim of the present study was to investigate the expression of the mammary-derived growth inhibitor (MDGI) and the subcellular localization of MDGI-related antigens in bovine mammary glands. Cell-free translation of poly(A+) = RNA, immunoprecipitation with rabbit anti-MDGI-antibodies, and estimation of the relative contents of MDGI by a radioimmunoassay in mammary tissue of different functional states revealed that the 13 kDa MDGI was dramatically increased in terminally differentiated mammary tissue compared with the proliferating tissue from pregnant animals. To address the question of tissue localization, polyclonal anti-MDGI antibodies and antibodies directed against a synthetic peptide corresponding to residues 69 to 78 of MDGI were used. Western blotting of tissue fractions revealed the cytosolic and microsomal localization of MDGI. Additionally, both types of antibodies detected a 70-kDa antigen in the nuclear fraction of differentiated mammary glands. Salt extraction and DNase I digestion of isolated nuclei, as well as chromatin purification, indicated an association of the 70-kDa antigen with the chromatin. By means of the immunogold technique, MDGI-related antigens were localized within euchromatic nuclear regions of epithelial cells in the intact differentiated mammary gland. The immunostaining was markedly diminished in the proliferating tissue. This finding raises the possibility that MDGI and the 70-kDa antigen influence cell proliferation by acting on gene expression within the nuclei of mammary glands.

Animals↗