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Biomedical subjects

L Weber

Publications and source records attributed to L Weber.

At least 199 records · Page 11Linked to original sources
PubMed1980

Thrombosis of the inferior vena cava after closure of atrial septal defect.

Although complications of atrial septal defect closure was rare, some sources of potential error should be kept in mind. In the case presented an enlarged Eustachian valve, mistaken as the lower rim of an atrial septal defect, was included in the direct repair and led to obstruction of the inferior vena cava. Caval thrombosis occurred subsequently. Early reoperation, resection of the Eustachian valve and removal of the thrombus were followed by an uneventful recovery.

Child↗
PubMed1979

Sexual dimorphism of mouse fetal brain lesions after X-irradiation prior to gonadal differentiation.

Fractionated X-irradiation of gestational days 11-13 in the mouse, with doses between 3 x 1.05 and 3 x 1.33 Gy resulted in rosette-like clusters of primitive ependym-resembling cells dispersed within the cortex walls. Quantification of these abnormalities showed a general prevalence in the female fetuses, especially due to the larger number of rosettes in the females than in the males. It was concluded that X-irradiation acts on sex-specific differentiation steps, which are fully developed at the beginning of the fetal period. As it was recently speculated that these are linked to an early divergence of gene expression between the sexes, we suggest that X-chromosome damage may be involved in the pathogenesis of the dimorphic lesion pattern. While, in principle, this will valid for any fetal tissue, it only becames evident in the forebrain because of the outstanding relationship between cell necrosis and rosette development in this specific organ.

Animals↗
PubMed1979

Sex-dependent action of prenatal fractionated X-irradiation in the mouse. Biochemical findings.

X-irradiation of pregnant NMRI-mice on gestational days 11-13 with 3 x 10.5 Gy increased postnatal mortality of the female offspring only. Weights, protein content and acetylcholinesterase, as well as Na,K-ATPase activities in the brains of all treated offspring, were changed. There were, however, no differences between females and males with respect to these parameters.

Acetylcholinesterase↗
PubMed1979

Nature of collagen in dermatofibrosarcoma protuberans.

The nature of collagen from 2 cases of dermatofibrosarcoma protuberans was studied. For this purpose, the tumor tissue was carefully separated from adjacent normal dermis. The collagen types comprised in the tumor were identified by CM-cellulose chromatographic and SDS-gel electrophoretic analysis of the component alpha-chains. Semiquantitative evaluation of the relative type III content was established by separation of the cyanogen bromide peptides on gels of 12% polyacrylamide in SDS. These studies showed that dermatofibrosarcoma protuberans contains alpha 1(I)-, alpha 2-, and alpha 1(III)-chains as well, and corresponding type I- and type III-related CNBr peptides. Comparing the collagen from dermatofibrosarcoma protuberans to that of normal skin, the relatively increased type III content in the case of dermatofibrosarcoma protuberans becomes apparent.

Adult↗
PubMed1978

Collagen polymorphism in pathologic human scars.

The collagen type composition of normal and pathologic scars was examined in comparison with normal skin from the same individual. Particular care was taken to separate scar tissue from adjacent normal dermis. After urea extraction, the tissue specimens were cleaved with cyanogen bromide. The presence of the dermal collagen types I and III was deduced from the electrophoretic distribution patterns of the CNBr peptides in 12% SDS-polyacrylamide gels. The intensity of the type III specific peptide bands correlates with the type III content of the samples. Using this method, the presence of both type I and III collagen can be proved in normal as well as pathologic scars. The type III content in older normal scars is slightly increased, whereas the type III content of pathologic scars is significantly increased in comparison with the type III content of normal skin. The electrophoretic CNBr peptide distribution pattern of pathologic scar tissue is almost the same as that of fetal skin. Both are clearly different from the peptide pattern of normal adult skin.

Adult↗
PubMed1977

Dermal architecture and collagen type distribution.

The human dermis consists of two morphologically different layers. A loose meshwork of thin collagenous fibres is characteristic for the adventitial dermis with includes the papillary and the periadnexal dermis. Thick, coarse collagen bundles are the main feature of the reticular dermis. Two different collagens, type I and type III occur in the dermis as shown previously by biochemical analyses. Antibodies specific for type I collagen or type III collagen and their corresponding precursors were used in indirect immunofluorescence tests to localize the various collagens in frozen sections of normal adult skin. Whereas type I collagen is found in all dermal layers, the main part of type III collagen can be found within the adventitial dermis. Antibodies against the precursor of type I collagen stain only a bandlike region immediately beneath the epidermis. Antibodies against the precursor of type III collagen stain the same regions as antibodies against the helical part of type III collagen.

Antibodies↗
PubMed1977

SDS-polyacrylamide gel electrophoretic determination of type I and type III collagen in small skin samples.

A sodium dodecylsulfate-polyacrylamide electrophoretic method, which in contrast to other biochemical procedures, e.g. differential salt precipitation or ion exchange chromatography and molecular sieve chromatography, is applicable to smallest amounts of protein, is shown to be suitable for the determination of the collagen types from small skin samples, such as routine skin biopsies. After urea extraction, the tissue samples are cleaved with cyanogen bromide. The resulting CNBr peptides derived from the different alpha-chains are resolved in 12% SDS-polyacrylamide gels. Densitometric profiles of the gel electrophoretic patterns correspond to the collagen type content of the tissue specimens. Comparing fetal to adult skin, the higher content of type III collagen in the case of fetal skin can be demonstrated.

Adult↗
PubMed1976

Base sequence complexity of the stable RNA species of Drosophila melanogaster.

The base sequence complexity of Drosophila transfer RNA (tRNA), 5S RNA, and 18S + 28S ribosomal RNA was determined by analyzing the kinetics of RNA-DNA hybridization on membrane filters. We find that Drosophila tRNA is made up from about 59 basic nucleotide sequences distinguishable by hybridization, suggesting that many of the 99 tRNA species resolved by reverse phase chromatography (RPC-5) are homogenic. In contrast 5S RNA was found to contain a single family of sequences. Either 18S ribosomal RNA (rRNA) alone, or 18S + 28S rRNA together, behaved kinetically as two sequence families, and the possible basis for this unexpected result is discussed.

Animals↗
PubMed1976

The ribosomes of Drosophila. III. RNA and protein homology between D. melanogaster and D. virilis.

The extent of interspecific homology between D. melanogaster and D. virilis for ribosomal RNA and ribosomal protein was examined using the techniques of two-dimensional gel electrophoresis, and RNA-DNA filter hybridization. Only 2 of the 71 ribosomal proteins resolved were found to be species specific, while comparisons of soluble larval hemolymph protein patterns showed little similarity. Depending on the technique employed, the sequence homology for 18S + 28S ribosomal RNA was found to be between 83-94%, and sequence homology for 5S rRNA was judged to be complete.

Animals↗
PubMed1975

Macrophage inhibiting activity in serum and central lymph of Listeria-immune mice.

Serum and central lymph from mice immunized with live Listeria monocytogenes six days previously and boostered four hours before collection exerted significant inhibition of macrophage migration in vitro. It is concluded that lymphokines or lymphokine-like products of the cellular immune reaction are released in vivo and are possibly instrumental in the generation of acquired cellular antibacterial immunity.

Animals↗
PubMed1974

The ribosomes of Drosophila. II. Studies on intraspecific variation.

Electrophoretic comparisons of 40S and 55S ribosomal subunit proteins from 18 strains of Drosophila melanogaster revealed the virtual absence of allelic variation. More detailed two-dimensional studies on the large subunit proteins in 6 of the strains demonstrated additional complexity but still no interstrain variation. The significance of these results is discussed with respect to present estimates of genic heterozygosity in natural populations.

Alleles↗