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Biomedical subjects

M Bihari-Varga

Publications and source records attributed to M Bihari-Varga.

At least 37 records · Page 2Linked to original sources
PubMed1981

Changes in the physical behavior of low density lipoprotein in the presence of glycosaminoglycans and high density lipoprotein.

Temperature dependent techniques - differential scanning calorimetry (DSC), polarizing microscopy - were used to study the properties of human serum low density lipoprotein (LDL) and its glycosaminoglycan (GAG) complexes, and to investigate the influence of the addition of high density lipoprotein (HDL) to the complex system. In the LDL molecule a reversible endothermic transition took place with its peak at 33 degrees C. Cholesteryl esters within the LDL core existed as an isotropic solution above this temperature (i.e. around body temperature), and in the form of smectic liquid crystals below it. When LDL was converted in vitro into GAG-LDL complexes by the addition of chondroitin-6-sulfate, dermatan sulfate, heparin or heparan sulfate, the DSC curves showed an evaluation of the transition temperature: the peak values in these samples were found at 40 degrees C and under the polarizing microscope a birefringence developed, typical of smectic liquid crystals. In chondroitin-4-sulfate-LDL complexes no alteration of the physical structure of the LDL molecule could be demonstrated. HDL decreased the transition temperature of GAG-LDL complexes and the disappearance of birefringence indicated that in the presence of HDL the lipids within the GAG-LDL complexes existed in a liquid phase at a temperature in the vicinity of body temperature.

Calorimetry, Differential Scanning↗
PubMed1981

The synthesis, transport and excretion of connective tissue macromolecules by smooth muscle cells.

SMC-s both in vivo and in vitro have a function in matrix macromolecule production. Under certain conditions the synthesizing function of the SMC-s seems to be more important than their contractile function. The modified less differentiated SMC-s participate in the synthesis of connective tissue macromolecules while the differentiated "resting" SMC-s maintain the functional activity.

Animals↗
PubMed1981

The effect of chondroitin-sulfate and hyaluronic acid on glycosaminoglycan and collagen synthesis and secretion by cultured arterial endothelial cells.

The effect of the addition of chondroitin-sulfate or hyaluronic acid to the culture medium on the glycosaminoglycan and collagen content and on the glycosaminoglycan composition of pig arterial endothelial cells and of the culture medium has been studied by biochemical and morphological methods. Both chondroitin-sulfate and hyaluronic acid were found to be transported to the interior of the cultured cells and then degraded. CSA, in addition enhanced collagen synthesis within the cells, but not the rate of excretion. Hyaluronic acid did not influence collagen formation.

Animals↗
PubMed1981

Age-related changes in the glycosaminoglycans and collagen of cultured pig endothelial cells.

Pig aortic endothelial cells were grown from aortic intimal explants. Tissue culture samples were obtained at regular intervals between the 2nd and 21st day (time-course experiments) and between the 2nd and 15th passage (influence of subcultivation). Glycosaminoglycans (GAG-s) were isolated separately from the cells and from the medium. The various GAG-s were identified by electrophoresis on cellulose acetate strips, by differential degradations with HNO2 and by digestion with selective enzymes, and their concentration was measured. Protein and collagen content was also determined. Parallel tissue culture monolayers were investigated by microscopical methods. Total GAG and collagen concentrations showed maximum curves when plotted as a function of the time of incubation, with peak values on the 9th day, both in the cells and in the medium. From among the individual GAG-s the amount of hyaluronic acid and chondroitin-sulfate increased gradually, while heparan-sulfate content changed in the opposite direction. Chondroitin was detectable only in the culture medium; its concentration decreased steeply until the tenth day. Alterations in the dermatansulfate content showed inverse tendency. The production and excretion of collagen and of GAG-s increased during the first six passages, both in the cells and in the media, and then declined during the four following ones. The ratio of the individual GAG-s did not alter until the tenth subculture. Further subcultivation resulted in a gradual increase in the relative amount of chondroitin-sulfate and a decrease in heparan sulfate contents.

Aging↗
PubMed1980

Synovial membrane in rheumatoid arthritis: determination of glycosaminoglycans and age-dependent correlations.

From 16 synovial membranes patients with rheumatoid arthritis morphological parameters as well as the GAG distribution pattern have been determined using 2 methods each. The results were checked by discriminant and regression analysis: The total GAG concentration of the synovialis was significantly correlated with the sum of the parameters "fibrin in organization", "granulocytes" "nad "necroses" (acute activity). A highly significant correlation between the age of patients and the severity of chronic morphological alterations (basic activity, especially proliferation) was found. The percentage of CS plus DS was positively correlated with the age of patients as well as with the basic activity of the disease, especially with the proliferation. - Contrary to this, HA was significantly decreased when related to the "chronic" parameters. No correlation could be demonstrated between the GAG components and criteria of the acute activity. The evaluating system of STIEHL and GEILER is to be preferred for obtaining morphologic-biochemical correlations. Furthermore, a diagram is proposed demonstrating the cumulative progression of rheumatoid arthritis in the synovialis as related to the GAG pattern. Its combination with morphological data (scars, proliferation, exudation) may help to describe the development of the disease more acurately.

Adolescent↗
PubMed1980

Endothelial glycosaminoglycans-in vitro studies.

Endothelial cells were grown from pig aortic intimal explants. Collagen and glycosaminoglycan (GAG) content and GAG distribution was measured in the cells and in the culture medium as a function of the time on incubation and of subcultivation. The influence of the addition of chondroitin-6-sulfate or hyaluronic acid to the medium has also been studied.

Animals↗
PubMed1976

Thermoanalytical and histological study of intra-articular papain-induced degradation and repair of rabbit cartilage. II. Mature animals.

The effect of papain treatment on the cartilage tissue of the knee joint of mature rabbits was studied by histological and thermoanalytical methods. Changes taking place in the composition of cartilage in the course of ageing were shown. As a result of papain treatment a significant irreversible destruction of the ground substance took place. Papain-induced loss of proteoglycans and the intensity of repair reactions and age-related differences are discussed.

Aging↗
PubMed1975

Early changes in the composition of rabbit articular cartilage following experimentally produced intra-articular fractures. A histological and thermoanalytical study.

Intra-articular fractures were produced in rabbit knee joints. The articular cartilage of the injured joints was processed histologically and analysed by a complex thermoanalytical method. It was demonstrated that intra-articular fractures in the early stages have essentially no irreversible damaging effects on the composition of articular cartilage of injured joints.

Animals↗
PubMed1975

Composition and macromolecular structure of intima in normal and arteriosclerotic human aorta.

Proteoglycanes, glycoprotein, fibrous collagen and elastin proteins were isolated from normal human aortic intima and from sclerotic lipid and calcium plaques and examined by electron microscope and thermal analysis. Differences between the structure and compositon of normal human aortic wall and aortic lipid plaques are chiefly found in the proteoglycan containing fraction. The calcium plaque shows structural changes in the fibrillar protein components.

Aorta↗