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Biomedical subjects

M Wolman

Publications and source records attributed to M Wolman.

At least 91 records · Page 5Linked to original sources
PubMed1976

Effect of levan on the stages of development of experimental allergic encephalomyelitis.

Experimental allergic encephalomyelitis was induced in male guinea pigs of the N13 strain by inoculation of an emulsion of basic protein of myelin with complete Freund's adjuvant. The disease was also passively transferred to other animals of the same strain by i.p. injection of sensitized lymphocytes obtained from donors inoculated with the antigenic emulsion eight days previously. Daily administration of levan markedly reduced the incidence and severity of the disease in actively sensitized animals. Little, if any, effect was obtained by levan treatment of animals with the passively transferred disease. The findings indicate that the previously reported inhibitory effect of levan on the development of experimental allergic encephalomyelitis is probably due mainly to a derangement of the afferent path (stage of sensitization). Administration of levan also causes a depletion of lymphocytes in the lymph nodes and this may presumably also affect the efferent path.

Animals↗
PubMed1976

Effects of route and schedule of administration of high-molecular levan on the growth of AKR lymphoma.

The route and schedule of treatment with high-molecular levan markedly influences its inhibitory effect on the growth of transplanted AKR lymphoma. Injections of levan into the site of the primary tumor were more effective in inhibiting tumor growth and preventing tumor-associated weight loss and mortality than were i.p. injections. Local levan injections inhibited metastatic spread only in mice treated from Days 0 and 2. Levan i.p. was more effective in inhibiting metastases in animals started on treatment 7 to 13 days after tumor inoculation than in animals in which levanization was started earlier. Local injection of levan before inoculation of tumor enhanced tumor growth and shortened life-span in comparison to nonlevanized animals. In mice treated with levan for a short period only, the inhibitory effect on tumor growth slowly vanished within 2 weeks. Some animals treated for 5 to 8 months remained completely free of tumor. The results indicate that the effect of levan on tumor development is mainly topical and depends on the concentration of the polysaccharide in the site. The tumor growth period from 0 to 5 days appears to differ from the following period in the reaction to levan treatment. The nature of this difference is not clear, but possible explanations are discussed.

Animals↗
PubMed1976

Experimentally produced hypertension and aortic acid esterase.

The effect of hypertension, which is known to enhance atherosclerosis, on acid esterase activity of rat aortic wall was studied histochemically. The purpose was to test our notion that atherogenesis depends on the balance between supply of lipids to the arterial smooth muscle cells and the lysosomal esterase activities. Hypertension was produced in rats by unilateral nephrectomy and administration of desoxycorticosterone acetate and sodium chloride. The animals reacted with varying degrees of hypertension. In rats with hypertension of a sufficiently high degree and of long duration, inhibition of aortic acid esterase activities occurred. No inhibition of these enzymes occurred in the other organs examined.

Animals↗
PubMed1975

Oxidation of lipids and membranes I: in vitro formation of peroxidative lipid polymers.

Fluorescent polymers were obtained by oxidizing partly emulsified linolenic acid with different oxidants. The speed of formation of polymers differed for the various oxidants, and the difference was not a simple function of the oxidation potential. The speed of polymerization also depended on the nature of the emulsion. The presence of egg albumen in the emulsion enhanced polymer formation with all oxidants. When the oxidants used are arranged in the order of decreasing speed of polymer formation, the order is different in the presence of albumen from what it is in the absence of albumen. With different oxidation catalysts most antioxidants and amino acids tested enhanced polymerization. In oxidation with ferric ions, with K-dichromate, and without added oxidants the only antioxidants which delayed polymerization were "inhibitors." "Retarders" enhanced polymerization. With KMnO4 slight delay was caused by some retarders. The findings indicate that not only oxidation catalysts, but also proteins, amino acids, and antioxidants enhance polymerization. The possibility is suggested that in animal cells lipid pigment formation might represent a mechanism for neutralizing free radicals.

Amino Acids↗
PubMed1975

Oxidation of lipids and membranes II: Effects of oxidants on cerebral white matter homogenates.

Bovine cerebral white matter homogenates were oxidized by various oxidizing solutions of equal molarity and subsequently extracted with water. Most of the oxidants tested (K-dichromate, FeCL3, H2O2, O2, and chloroperbenzoic, ascorbic, performic, and periodic acids) rendered the various myelin constituents less extractable than the constituents of unoxidized control homogenates. KMnO4, and to a lesser degree hemoglobin, rendered myelin constituents more extractable with water than those of the control homogenates. The findings indicate that most of the oxidants produced stabilization of the lamellar pattern, probably through cross-linking and polymerization. KMnO4 and hemoglobin caused labilization and breakdown of the membranous structure. Proof that stabilization of membranes is caused by some oxidants and that fragmentation occurs by the action of KMnO4 and hemoglobin was obtained by the light scattering technique and by electron microscopy of the oxidized homogenates. Evidence obtained indicated that formation of hydrophobic end groups during oxidation favors polymerization, while prevalence of hydrophilic groups is associated with fragmentation.

Animals↗
PubMed1975

Effect of native levan on homograft rejection in mice.

The effect of high-molecular-weight levan on skin graft rejection was studied. Daily ip administration of 15-30 mg levan was shown to delay rejection in Balb/c and C57BL recipient mice. An increase in MST value by 3.6 days was obtained in Balb/c mice and of 5.6 days for C57BL.

Animals↗
PubMed1975

Ultrastructural aspects of the adherence to target cells of in vitro differentiated lymphocytes.

The specific adherence to target fibroblasts of lymphocytes differentiated in vitro from blast cells after stimulation with pokeweed mitogen was studied under the electron microscope. Lymphocyte pseudopods were seen to penetrate into the target cells forming a close contact between the membranes of the two interacting cells. Microfilaments were the only cytoplasmic components that could be detected within or in the vicinity of the penetrating pseudopods. No morphological signs of secretion could be observed in the contact region. Morphological aspects of the contact region are discussed as related to the lytic mechanism.

Animals↗
PubMed1975

Storage of polyvinylpyrrolidone mimicking a congenital mucolipid storage disease in a patient with Munchausen's syndrome.

A 24-year-old woman from the Sinai peninsula had, since the age of 15 years, repeatedly undergone surgery because of gastrointestinal bleeding. The bleeding was found to have been caused by self-inflicted injuries. Histiocytes in the patient's liver and lymph nodes (the spleen had been removed nine years previously) contained a peculiar material which was, in part, basophilic and had puzzling histochemical characteristics. The material is believed to be polyvinylpyrrolidone (PVP), which had been administered to the patient during one of her operations. The importance of recognizing this change, especially in countries where PVP is administered as a plasma expander, is stressed.

Adult↗
PubMed1975

Effects of high-molecular levan on the growth and spread of lymphoma in AKR mice.

Levan was shown to inhibit lymphoma development in AKR mice. Growth of tumor was inhibited at the site of injection and in metastases. Levan caused a decrease in the incidence of tumors, and it reduced pleomorphism, mitoses, and invasiveness of tumors in comparison to nonlevanized mice. Evidence of tumor cell destruction was observed in levanized mice. The effect of levan on tumor development was dose dependent.

Animals↗
PubMed1975

Acid esterase in the aorta of the hyperlipidemic rat: a histochemical study.

In rats maintained for about three weeks on a diet inducing hyperlipidemia E-600 resistant acid esterase activities were markedly reduced in the aorta in comparison with untreated animals. In rats which were maintained on an ordinary diet containing the same amount of thiouracil as given to the hyperlipidemic animals, only a slight reduction of acid esterase activities was noted. Another group of animals was fed an ordinary diet for three weeks after three weeks on a hyperlipidemic diet. In the aorta of these animals the acid esterase activities were almost normal. There was little fat deposition in the aortas of animals given the various diets. No such effects on esterase activities were observed in the liver and lung of animals of the various groups. Inhibition of acid esterase activity was also observed in rats kept on a hyperlipidemic diet for 65 days. In these animals patchy deposition of partly anisotropic lipid was observed in the intima and media.

Acid Phosphatase↗