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Biomedical subjects

S Roth

Publications and source records attributed to S Roth.

At least 91 records · Page 5Linked to original sources
PubMed1985

Are glycosyltransferases the evolutionary antecedents of the immunoglobulins?

The glycosyltransferases may be the evolutionary precursors of the immunoglobulins, although critical evidence for this hypothesis is not yet available. The transferases add sugars to non-glycosylated proteins, lipids, and organic molecules, as well as to oligosaccharides, glycoproteins, and glycolipids. The enzymes are specific, extremely polymorphic, occasionally inducible, and may be structurally related to one another. Circumstantial evidence links the transferases to both the MHC and T/t loci in the mouse. Finally, antibodies against purified transferases are difficult to produce and sometimes they react with immunoglobulins. The present hypothesis predicts that transferases should show some sequence homology with immunoglobulins, and that some MHC proteins will be glycosyltransferases.

Animals↗
PubMed1985

Use of chicken cell line LSCC-H32 for titration of animal viruses and exogenous chicken interferon.

The chicken embryo cell line LSCC-H32 was tested for the propagation and titration of several animal viruses of the families Toga-, Reo-, Rhabdo-, Herpeto-, Orthomyxo-, Paramyxo-, and Poxviridae and compared with secondary chicken embryo cells. The LSCC-H32 cells were demonstrated to be as susceptible for most of the tested viruses as were secondary chicken embryo cells. Both produced comparably sized virus plaques. The titers of Sindbis and Semliki Forest viruses in LSCC-H32 cells were 5- to 40-fold higher than in secondary chicken embryo cells or BHK-21 cells, respectively. Furthermore, exogenous chicken standard interferon was titrated in the LSCC-H32 cells, and a 50% plaque titer reduction of the challenging vesicular stomatitis virus was achieved by 0.12 IU of a standard chicken interferon preparation. Endogenous chicken interferon could not be induced by treatment of the cells with polyinosinic acid-polycytidylic acid. Due to its high plating efficiency and metabolic activities, the LSCC-H32 cell line provides a useful cell system for the titration and large-scale production of the tested animal viruses and for the titration of exogenous chicken interferon.

Animals↗
PubMed1985

[Radiotherapy of pancreas cancer--literature review].

Resection is the treatment of choice in organ-limited pancreatic cancer. In locally or regional, not completely resectable pancreatic cancer other therapeutic modalities are called upon: external beam radiotherapy results in relief of pain in 50% and average survival rate of about 10 months according to recent series in the literature. Loco-regional tumor control can be improved by intraoperative electrons or interstitial implantation of radioactive sources. - The combination of monochemotherapy (5-fluorouracil) and 40 Gy radiotherapy is well tolerated and tends to prolong survival also if given after curative resection.

Aged↗
PubMed1979

Galactosyltransferase from commerical preparations of fetuin.

A galactosyltransferase that transfers galactose from UDPgalactose to asialoagalacto fetuin or N-acetylglucosamine was partly purified from two commerical preparations of fetuin and its kinetic properties were characterized. Several other preparations of fetuin were also found to contain galactosyltransferase activity.

Animals↗
PubMed1979

Spontaneous glycosylation of glycosaminoglycan substrates by adherent fibroblasts.

SV40-transformed mouse fibroblasts migrate upon, and spontaneously glycosylate, plastic substrates derivatized with chondroitin-6 sulfate and hyaluronic acid. Autoradiography of cultures prelabeled with 3H-glucose and 3H-galactose demonstrates the presence of silver grains near adherent cells. Silver grains are particularly dense near cells cultured on chondroitin sulfate. No significant grains are observed on control dishes or dishes derivatized with polygalacturonic acid. Radioactive material left by cells is not removed by boiling the dishes in 8 M urea and 10% sodium dodecylsulfate, suggesting that it is covalently linked to the derivatized plastic. Acid hydrolysis shows that the radioactive material consists of glucuronic acid and N-acetylglucosamine when the prelabeled cells are cultured on hyaluronic acid. When cells are cultured on chondroitin sulfate, the radioactive product consists only of glucuronic and and N-acetylgalactosamine sulfate. Sonicates of prelabeled cells or the supernatants from cultures of intact prelabeled cells add no SDS-urea-resistant radioactivity to dishes derivatized with these glycosaminoglycans.

Animals↗
PubMed1978

Properties of a double gradient model for retinotectal specificity.

The properties of a double gradient model for retinotectal specificity are discussed. The model utilizes only two complementary molecules, each located on both retina and tectum, to determine position along the dorsoventral axis. Two possible modes of interaction between these molecules are assumed. One of these allows all possible bonds between a retinal cell and tectal loci to be formed. This results in a rigid retinotectal projection in which the adhesion of each retinal cell to its normal tectal locus is maximal. The other assumes stochastic interactions between the molecules, and results in retinotectal specificity only if additional constraints are imposed on the system. Either of these modes of interaction predicts adhesive preferences for retinal cells to tectal halves similar to those observed experimentally.

Animals↗
PubMed1978

In vitro studies on neural specificity.

The migration of the retinal ganglionic axons through the optic nerve, over the tectal surface, and into the tectum to synapse correctly with brain neurons has been one of the most studied paradigms of neural specificity. Through the use of dissected tecta from the developing chick embryo, dissociated retinal cells can make the same choices in vitro that the ganglion cell termini make in vivo. That is, cells from the dorsal retina prefer to adhere to ventral tectum fragments and vice versa, in accord with the final map of the retina on the tectum. This assay has been used to analyze the biochemical components on the cell and tectal surfaces that might account for the recognition observed. Also, the assay has made it clear that virtually all the retinal cells can distinguish between dorsal and ventral tectal fragments, even though the cells of the retina that normally synapse with the tectum make up not more than 5% of the total population of the retina. One reason for this may be that, although only the retinal ganglion cells send their processes into the brain, these processes use all of the retina initially to get to the fundus of the retina, where the optic nerve begins. The vast majority of the retinal cells may possess surface recognition molecules not for finding the tectum but for serving as substrates for the few retinal cells whose axons must first leave the retina before finding the correct tectal locus.

Animals↗
PubMed1977

Nanosecond time-dependent fluorescence depolarization of diphenylhexatriene in dimyristoyllecithin vesicles and the determination of "microviscosity".

The nanosecond time dependence of the fluorescence depolarization of 1,6-diphenyl-1,3,5-hexatriene in L-alpha-dimyristoyllecithin vesicles was determined at temperatures above and below the midpoint of the gel-liquid crystalline transition. In neither case could the decay of the total fluorescent emission or the decay of the emission anisotropy be described adequately in terms of single exponential decay laws. At the lower temperature, the emission anisotropy did not approach zero in the time window available for measurement, a finding which may indicate that the range over which rotation of the probe can freely occur is restricted. The results are discussed in relation to the concept of microviscosity of bilayer membranes.

Benzene Derivatives↗