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Biomedical subjects

G Bauer

Publications and source records attributed to G Bauer.

At least 505 records · Page 28Linked to original sources

Release of particle associated RNA dependent DNA polymerases by primary chicken and quail embryo cells.

These results show that primary chick embryo cells in culture release a particle bound RNA dependent DNA polymerase into the culture fluid. The enzyme is also found in the allantoic fluid of embryonated chicken eggs. This phenomenon is not restricted to the chicken system because primary quail embryo cells which are not known to express the so far known endogenous viruses release a particle bound RNA dependent DNA polymerase as well. In both cases this enzymes may be part of an hitherto unknown endogenous viral system. However, since the expression of the chicken- and quail-enzyme goes through a sharp peak during embryogenesis one may speculate on a physiological role for the newly described enzymes during development.

Animals↗

Varieties of the locked-in syndrome.

The locked-in syndrome (LiS) was broken down on the basis of neurological symptoms in 12 patients. The criteria of classical LiS are total immobility except for vertical eye movements and blinking. If any other movements are present one should consider the condition as incomplete LiS. Total immobility, including all eye movements, combined with signs of undisturbed cortical function in the EEG led to the concept of total LiS. The anatomical basis for this condition consists of lesions in both cerebral peduncles which interrupt the pyramidal and corticobulbar tracts, the supranuclear fibers for horizontal gaze and the postnuclear oculomotor fibers. As to the course, chronic and transient LiS have been described.

Adult↗

RNA-directed DNA polymerase from particles released by normal goose cells.

Cells from a goose embryo were shown to release particle-associated RNA-directed DNA polymerase and RNase H activities that required the presence of Nonidet P-40 for detection. The particles were not infectious and did not have endogenous DNA synthesis. The goose particle DNA polymerase was related to the DNA polymerase of spleen necrosis virus with respect to size and was inhibited by immunoglobulin G to spleen necrosis virus DNA polymerase. However, goose cells producing DNA polymerase-containing particles did not contain reticuloendotheliosis virus-related nucleotide sequences in their DNA.

Animals↗

Pheasant virus DNA polymerase is related to avian leukosis virus DNA polymerase at the active site.

The DNA polymerase from Amherst pheasant virus (APV), a member of the pheasant virus species of retroviruses, was compared to the DNA polymerases of avian leukosis viruses (ALV) and a reticuloendotheliosis virus (spleen necrosis virus (SNV)). Immunoglobulin inhibition tests and competition immunoassays showed that APV and ALV DNA polymerases are closely related at their active sites. The determinants common to their active sites are not shared by SNV DNA polymerase. Bu using a species-specific radioimmunoassay, it was shown that both APV and SNV DNA polymerases are grossly different from ALV DNA polymerase. The specificity of the relationship of the active sites of APV and ALV DNA polymerases was confirmed by a heterologous radioimmunoassay. Our data indicate that pheasant viruses are evolutionarily linked to ALV.

Avian Leukosis Virus↗

Acute convulsions.

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Acute Disease↗

[Electroencephalographic changes in coma due to hepatic insufficiency with porto-caval shunt (author's transl)].

EEG studies were done in 19 patients comatose due to severe hepatic insufficiency associated with porto-caval shunting. The neurological deficits were graded in 5 stages and related to the abnormal EEG-pattern observed in 38 records. With deepening of coma, alpha-frequencies were gradually replaced by theta- and delta-activities. The frequency of theta- and delta-runs decreased with neurological deterioration. Triphasic waves (typical and/or atypical) were seen in 26% of the records. Typical triphasic waves were found to be limited to stage 3 of coma, whereas atypical forms appeared in earlier and later stages. After infusions of L-Valin, a transient improvement and disappearance of triphasic waves was observed, but no significant effect could be established on the final course of the disease. Sleep-like potentials and the reactivity to external stimuli decreased in deep stages of coma. Severe EEG abnormalities were correlated to low cholinesterase and high lactid acid blood level, but no correlation was found to the level of ammonia.

Alpha Rhythm↗

Comparison of the RNA-dependent DNA polymerase of an endogenous avian leukosis virus to the polymerase of an exogenous avian leukosis virus.

RNA-dependent DNA polymerases from Rous-associated virus-O and avian myeloblastosis virus were partially purified by affinity chromatography and compared to each other. The enzymes are indistinguishable in the immunoglobulin inhibition test and by several enzymological criteria, such as optimum curves for the concentrations of Mg2+, K+, H+; monophasic Lineweaver-Burk plot for dTTP and biphasic Lineweaver-Burk plot for dGTP. In thermal inactivation studies a small difference can be observed, suggesting a minor difference in the physical structures of the enzymes. Our findings are consistent with the idea that the RNA-dpendent DNA polymerases of endogenous and exogenous avian leukosis viruses are very closely related to each other and therefore may be regarded as one group of polymerases.

Antigen-Antibody Reactions↗

Purification and characterization of particles containing RNA-dependent DNA polymerase, in the allantoic fluid of uninfected leukosis virus-free chicken eggs.

The allantoic fluid of embryonated chicken eggs regularly contains particle-associated RNA-dependent DNA polymerase, as shown by its reaction with homopolymeric and heteropolymeric RNA and by the characterization of the products. The purification of the particles is described. The purified particles are different from the known avian RNA tumor viruses in their protein composition and their sedimentation constant. They do not exhibit biological properties typical for RNA tumour viruses, such as helper activity, interfering properties or infectivity and do not show endogenous DNA synthesis. The particles are discussed as non-viral elements.

Allantois↗