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Biomedical subjects

S Roth

Publications and source records attributed to S Roth.

At least 325 records · Page 18Linked to original sources
PubMed1985

Topology of UDP-galactose cleavage in relation to N-acetyl-lactosamine formation in Golgi vesicles. Translocation of activated galactose.

UDP-galactose appears to be produced on one side of a membrane barrier, opposite the galactosyltransferases that use it as a sugar donor. The translocation of activated galactose across membranes was studied in rat submaxillary-gland microsomal vesicles and in rat liver Golgi vesicles. When these intact vesicles containing the acceptor, N-acetylglucosamine, were incubated in the presence of UDP-galactose and two inhibitors of galactosyltransferase activity, the product, N-acetyl-lactosamine, formed within the vesicles. Thus at least the galactose moiety of UDP-galactose crossed the membranes. When intact Golgi vesicles were incubated with UDP-galactose labelled in both the uridine and the galactose moieties, labelled N-acetyllactosamine was again produced in the vesicles, but less than stoichiometric amounts of the uridine label was found there. Calculation of internal and external concentrations of UMP, a major product released from the cleaved uridine moiety, showed that the vesicles were actually enriched in UMP. When free UMP was incubated with the vesicles, this enrichment did not occur. This result was direct evidence for facilitated transport of UDP-galactose into the Golgi for use by galactosyltransferase.

Amino Sugars↗
PubMed1985

A collagen:glucosyltransferase at the surface of malignant fibroblasts.

3T12 fibroblasts possess glucosyltransferases that catalyze the transfer of glucose from UDP-Glucose to galactosylhydroxylysyl residues on collagenous acceptors. The presence of the enzyme activity at the cell surface is indicated by the following findings: a) suspensions of intact cells, as well as intact cell monolayers, glucosylate gelatinized collagen b) glucose transfer is not due to UDP-Glucose hydrolysis and subsequent intracellular utilization of the free glucose c) experiments using cell suspensions with known proportions of broken cells indicate that the glucosyltransferase activity is attributable to intact cells and not to contamination by intracellular enzymes from broken cells. The Km value for UDP-Glucose is about 20 microM. The enzyme has a pronounced requirement for manganese, and shows highest activity between 2 and 10 mM. The optimal Mn2+ concentration for the intracellular gelatin:glucosyltransferase activity is more restricted (5 to 10 mM). Glucosyltransferase activity is strongly inhibited by diamide and N-ethylmaleimide (5 mM), suggesting that intact sulfhydryl residues present in the enzyme are essential.

Animals↗
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↗
PubMed1984

Coping with abortion.

This study evaluated individual differences in coping style in response to an abortion procedure. The 55 subjects displayed a wide range of responses, although the average level of distress was fairly high. These women were quite similar to other stressed populations in their response to the Impact of Event Scale, providing evidence for a generalized stress response syndrome. When divided into groups based on coping style, "avoiders" were found to experience more distress that "nonavoiders," and "approachers" decreased in distress over time while "nonapproachers" did not. The implications of these findings are discussed in the context of the interaction between coping styles and counseling strategies.

Abortion, Induced↗
PubMed1984

Aleutian disease virus in B and T lymphocytes from blood and spleen and in bone marrow cells from naturally infected mink.

In the nuclei of 4% of peripheral blood or spleen mononuclear cells (MNC), Aleutian disease virus(ADV)-specific antigens were found by a direct immunofluorescence test. The MNC were further fractionated by nylon wool, affinity chromatography using Staphylococcus aureus protein, or Percoll gradient techniques. ADV and specific antigens were detected in MNC fractions enriched in either the B or T lymphocytes. In the bone marrow, up to 40% antigen-positive cells were demonstrated over a period of 15 months. These findings were confirmed by the detection of infectious virus in the MNC of blood and spleen and in bone marrow cells. Adherent cells from mink and control cells from ADV-negative ferrets were negative in both tests. These findings indicate that ADV exhibits a lymphotropism and can persist in the B- and T-cell fractions from ADV-infected mink over a long period of time. Furthermore, co-cultivation of mink MNC and bone marrow cells with the CCC clone 81 cells was shown to be reproducible method for the detection of ADV in persistently infected mink.

Aleutian Mink Disease↗
PubMed1983

Propagation of Aleutian disease parvovirus in cell line CCC clone 81.

Aleutian disease parvovirus (ADV), mutant Gorham of the Utah-1 strain, was grown and comparatively assayed in feline cell lines CRFK and CCC clone 81 at 31.8 degrees C. The maximum virus titres as determined by a fluorescent focus assay were found to be about 10(5) FFU/ml in CRFK at day 6 p. i. and 10(6) FFU/ml at day 4 p. i. in CCC clone 81 cells. Shifting of the incubation temperature from 31.8 to 37 degrees C led to a reduced virus production after three passages. The synchronization of the CCC clone 81 cells by 1 X 10(-3) M hydroxyurea followed by infection with low (less than or equal to 0.8) multiplicities of infection (MOI) did not significantly influence the virus titres. Several mammalian cell lines such as MiCl 1 (S+L-), Mv1-Lu, 64F3 clone 7 and FEF or fish cell lines such as BB and CHSE 114 developed abortive infections after inoculation with the temperature-sensitive mutant Gorham of the ADV strain Utah-1 (ADV-G). Three new isolates designated ADV-Sl1--ADV-Sl3 were isolated from spleen and blood lymphocytes and bone marrow cells of ADV-infected mink and were adapted to grow in CCC clone 81 cells at 31.8 degrees C with virus titres between 10(4) and 10(4.7) FFU/ml. ADV particle populations varying in their bouyant density between 1.32, 1.36 and 1.43 g/ml were isolated from infected cells and culture supernatants. By protein blotting and immunodetection two major protein components with apparent M. W. of 85 and 75 KD and three minor polypeptides of 33, 28.9 and 27.5 KD were detected.

Aleutian Mink Disease↗
PubMed1983

A new assay and cellular localization for an inducible glucuronyltransferase in the embryonic chick liver.

A direct, radioisotopic assay is described for the uridine diphosphate glucuronic acid (UDPGA): p-aminophenol glucuronyltransferase. The assay uses solid phase p-aminophenol-Sephadex as the glucuronyl acceptor and UDP-[14C]GA as the glucuronyl donor. After incubation with the enzyme, the derivatized Sephadex beads are washed in SDS-urea or with high salt concentrations to remove all labeled material except for that covalently attached to the beads. Sonicated livers from chick embryos exposed to phenobarbital for at least 5 days transfer more than ten times the glucuronic acid to derivatized beads than do uninduced livers of the same developmental age. Glucuronyl-transferase activity can be detected on intact, living cells after 5 days of phenobarbital induction, whereas sonicate activity is detectable within 3 days of induction. Suspensions of living cells can show 25% the activity found in the same suspension after all the cells are lysed by sonication.

Adenosine Triphosphate↗
PubMed1983

Biochemical studies in a patient with subacute neuropathic Gaucher disease without visceral glucosylceramide storage.

Autopsy samples were obtained from a 12.5-year-old girl who died with a neurologic disorder consisting of myoclonus, myoclonic epilepsy, spasticity, strabismus, and mild mental retardation but no hepatosplenomegaly. Studies in leukocytes, cultured skin fibroblasts, brain, liver, and spleen of this patient revealed glucosylceramide beta-glucosidase (EC 3.2.1.45, glucocerebrosidase) activity about 10% of controls, and well in the range found in samples from Gaucher disease patients. Extraction of the lipids from liver and spleen with chloroform-methanol (2:1) did not show accumulation of glucosylceramide or other lipid. Examination of the lipids in brain by high performance liquid chromatography revealed the presence of glucosylceramide, which is not found in brain samples from controls. Pathologic examination of the liver and spleen revealed no evidence of Gaucher disease. The brain showed many degenerative lesions and loss of neurons. There was no complementation of glucocerebrosidase activity when the cells from this patient were hybridized with cells from patients with Type 1 or Type 2 Gaucher disease. The reason for the lack of glucosylceramide storage in the liver and spleen has not been determined.

Autopsy↗
PubMed1982

A protein activator of galactosylceramide beta-galactosidase.

A heat-stable protein was isolated from the spleen of a patient with Gaucher's disease. This protein will activate glucosylceramide beta-glucosidase activity (Ho, M.W. and O'Brien, J.S. (1971) Proc. Natl. Acad. Sci. U.S.A. 68, 2810-2813). When the specificity of this activator was tested using other enzymes and substrates, it was found to activate galactosylceramide beta-galactosidase activity and sphingomyelinase but not GM1 beta-galactosidase or sulfatide sulfatase. The ability to stimulate galactosylceramide beta-galactosidase was optimum at pH 4.6 in the presence of pure phosphatidylserine or other acidic lipids such as sulfatide and phosphatidylinositol. The partially purified activator protein could stimulate galactosylceramide beta-galactosidase activity in brain, liver, leukocytes and cultured fibroblasts. It was not able to stimulate the activity of this enzyme in tissue samples from patients with Krabbe's disease, demonstrating that it was acting on galactosylceramide beta-galactosidase and not GM1 beta-galactosidase. It was slowly denatured by treatment with Pronase, reaching 16% of starting levels after 24 h at 50 degrees C. Attempts to separate the abilities of this activator preparation to stimulate several lysosomal hydrolases by column chromatography were not successful.

Brain↗
PubMed1982

The discovery of a lipid-linked glucuronide and its synthesis by chicken liver.

Upon incubation with uridine diphosphate-[14C]glucuronic acid, membrane fractions from adult and phenobarbital-induced embryonic liver synthesize a single glucuronide, which is soluble in chloroform:methanol (2:1). The compound is completely hydrolyzed and glucuronic acid released by either mild acid or beta-glucuronidase, whereas mild base hydrolysis results in a mixture of glucuronic acid and glucuronic acid-1,2-cyclic phosphate. These data and the behavior of the lipid-linked glucuronide on DEAE-cellulose chromatography indicate that the compound contains a monophosphate diester of glucuronic acid, which is beta-linked to a lipid. The synthesis of the lipid-linked glucuronide in uninduced normal embryonic liver is very low (5-15 pmol product/mg/5 min) at all developmental ages up to hatching, but the introduction of phenobarbital into the air space of a 9-10-day-old embryo causes a premature increase of activity (75-150 pmol products/mg/5 min) within 7 days. The glucuronyltransferase in adult and induced embryonic liver has a Km for UDPGlcUA of 0.17 x 10(-3) M and a broad pH optimum between pH 6 and 7. Glucuronic acid is released from the lipid-linked glucuronide by a beta-glucuronidase in liver that is active at neutral pH and is not inhibited by saccharolactone. This glycosidase activity appears, therefore, to be distinct from the previously characterized lysosomal beta-glucuronidase. Fractionation of adult chicken liver membranes by differential centrifugation indicates that over 70% of the glucuronyltransferase is associated with the nuclear and mitochondrial fractions. The endogenous beta-glucuronidase capable of hydrolyzing the lipid-linked glucuronide was not separated from the glucuronyl-transferase activity during fractionation. The data available suggests that the lipid-linked glucuronide is involved directly in the generation of free glucuronic acid for further metabolism.

Animals↗
PubMed1982

Comparison of oral propranolol and verapamil for combined systemic hypertension and angina pectoris. A placebo-controlled double-blind randomized crossover trial.

The relative efficacies of oral verapamil, a calcium-entry blocking drug, and propranolol, a beta-adrenergic blocking drug, were compared in 12 patients who had both stable angina pectoris and mild to moderate systemic hypertension, using a placebo-controlled, double-blind, randomized crossover protocol. Compared with placebo, both propranolol and verapamil decreased the frequency of anginal attacks and the number of nitroglycerin tablets consumed, and increased exercise duration and total work; there were no significant differences in the antianginal effect of the two drugs. Both verapamil and propranolol reduced the supine and standing systolic and diastolic blood pressure measured at rest; compared with propranolol, however, verapamil had greater effects on standing diastolic blood pressure (p less than 0.002). Resting heart rate was reduced from placebo baseline with large doses of both drugs; compared with verapamil, however, propranolol exerted greater effects on resting heart rate and rate-pressure product. Plasma renin activity was increased from placebo baseline with verapamil (p less than 0.05), but was reduced with propranolol (p less than 0.05); no significant change in plasma aldosterone was seen with either drug. Verapamil appears to be a safe and effective treatment alternative to propranolol for relieving anginal symptoms, improving exercise tolerance, and reducing elevated systemic blood pressure in patients with both angina pectoris and mild to moderate systemic hypertension.

Adrenergic beta-Antagonists↗
PubMed1982

Comparative effects of abrupt withdrawal of propranolol and verapamil in angina pectoris.

The potential hazards of abrupt withdrawal of propranolol have been described in patients with angina pectoris; however, the effects of abrupt withdrawal from long-term therapy with verapamil have not previously been investigated. The comparative effects of withdrawal from long-term treatment with propranolol and verapamil were assessed in a placebo-controlled double-blind randomized crossover study of 20 patients received placebo for 2 weeks, then increasing doses of propranolol (60 to 320 mg/day) or verapamil (240 to 480 mg/day) for 3 weeks. Patients were then abruptly withdrawn from drug onto placebo for 1 week, followed by crossover to the other drug treatment and a second withdrawal period. All 20 patients were withdrawn from verapamil without evidence of a rebound increase in frequency of anginal attacks, blood pressure, heart rate, or rate-pressure product and without a rebound deterioration in exercise tolerance. In contrast, with propranolol withdrawal, 2 patients (with the highest baseline angina attack rate) had a severe exacerbation of their anginal syndrome and could not undergo formal exercise testing; the other 18 patients were withdrawn from propranolol without incident. Plasma catecholamines were increased during exercise compared with rest during all treatments; however, the levels of catecholamines during exercise were significantly higher with propranolol than with verapamil and placebo (p less than 0.05). Levels of exercise catecholamines returned to placebo baseline values after withdrawal of propranolol.

Angina Pectoris↗