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Biomedical subjects

M Adam

Publications and source records attributed to M Adam.

At least 163 records · Page 9Linked to original sources
PubMed1984

Changes in collagen metabolism--another look at osteoarthrosis.

Collagen types I and III were isolated from osteoarthrotic cartilage. Immunofluorescence study has shown that these two collagen types are present in the deep layers of cartilage. Additional staining for fibronectin revealed the presence of the cell-adhesive protein in osteoarthrotic cartilage. Neither collagen type I and type III nor fibronectin were found in control cartilage. A passive haemagglutination assay determined anticollagen antibodies (against types I, II and III) in sera of some osteoarthrotic patients.

Cartilage, Articular↗
PubMed1984

Application of enzyme immunoassays to coagulation testing.

Enzyme immunoassays are very useful for the detection of low concentrations of coagulation proteins and pathological markers in plasma. Analytes in the ng/mL range are measurable with good reproducibility with intra- and interassay CVs of less than 5% to 10%. "Sandwich" methods have been developed for von Willebrand factor (plasma concentration about 8 micrograms/mL, Factor IX (5 micrograms/mL), protein C (4 micrograms/mL), and Factor X (10 micrograms/mL). However, this technique is only suitable for macromolecules; for low-molecular-mass peptides such as fibrinopeptide A a competitive method is used. Normal concentrations of fibrinopeptide A are below 3 ng/mL, with greater values suggesting in vivo generation of thrombin; thus this test is quite useful in detecting thrombosis. Reagents for both the sandwich and competitive methods are commercially available and cost effective, and have a longer shelf-life than those for radioimmunoassays.

Binding, Competitive↗
PubMed1983

[Antidigoxin Fab-fragments in suicidal digoxin poisoning. Successful treatment of recurrent ventricular fibrillation].

A 49-year-old woman took about 12.5 mg digoxin with suicidal intent. Severe arrhythmias, including recurrent ventricular fibrillation, occurred. Sheep Fab fragments of digoxin-specific antibodies were administered i. v. at a dose of 480 mg. Serum free-digoxin concentration fell within half an hour to 0, with simultaneous rise of total digoxin from 13 micrograms/l to a maximum of 176 micrograms/l after 2 hours. At the same time there was marked improvement in the clinical condition with restoration of a stable sinus rhythm. There were no side effects to the Fab fragment administration.

Antibodies↗
PubMed1983

Altered expression of collagen phenotype in osteoarthrosis.

Immunofluorescence studies have shown the presence of collagen type III in addition to types I and II in osteoarthrotic cartilage. The presence of collagen type III was verified biochemically: collagen was isolated and purified from the pronase digest of osteoarthrotic cartilage. Mixtures of different collagen types were fractionated first by two different DEAE-cellulose runs and then the collagen polymers were isolated by molecular sieve chromatography. Afterwards the collagenous material was reduced, Alkylated, and rechromatographed on an agarose column. Three major peaks corresponding to gamma-, beta- and alpha-chains were observed. Amino acid analyses and the CNBr peptide pattern indicated the identity of the alpha peak as alpha 1 (III). Additional staining of control and disease cartilages for fibronectin revealed the presence of this protein in the diseased tissue.

Bone Diseases↗
PubMed1983

Evidence for vitamin D dependent gamma-carboxylation in osteocalcin related proteins.

The content of gamma-carboxyglutamic acid (gla) was determined in rat femoral bone and kidney cortex in rachitic and vitamin D treated animals. It was demonstrated that the level of gla is decreased in vitamin D depleted animals both in kidney cortex and femoral bone. Supplementation of vitamin D deprived animals with this vitamin resulted in an increase in the gla concentration to almost normal levels. Also the incorporation of 14C NaHCO3 in renal cortex microsomes from rachitic animals was blocked. It is suggested that the absence of gla resulted from the direct action of vitamin D on mRNA for the Ca-binding protein.

1-Carboxyglutamic Acid↗
PubMed1983

Are the changes in collagen caused by chronical X-irradiation similar to aging?

It has been shown that in the skin of chronically irradiated rats the proportion of collagen type III as compared to collagen type I is increased; on the other hand, no changes in the overall proportion to collagen were observed in the skin. It appears that the increased proportion of collagen type III in chronically irradiated rats is responsible for the decreased solubility of cutaneous collagen in these animals. Concomitantly, indirect evidence was accumulated for the presence of an additional cross-link in type III collagen, present only when irradiated animals served as the collagen source. This cross-link is located subterminally as long as it is not removed by limited pepsin digestion. It was concluded that the physiological decrease in solubility and the decrease in solubility observed in chronically irradiated animals have a different molecular background.

Aging↗
PubMed1981

High fat diet induced fluorescence and increased resistance of collagen to proteolytic cleavage.

Feeding of animals with high fat diets results in a distinct increase in the stability of the collagen structure as reflected by its higher resistance towards proteolytic cleavage. It appears that covalent cross links are formed when the experimental animals are fed a diet containing a high proportion of unsaturated fatty acids, i.e. when the chance of the formation of reactive intermediates is increased. This is based on the observation of the presence of non-reducible high molecular weight collagenous material in pepsin treated collagen. This high molecular weight fraction exhibited a typical 390/460 nm fluorescence and a distinct decrease of lysine content. It is suggested that the observed phenomena result from the action of in vivo present potential cross-linking agents.

Animals↗
PubMed1981

The effect of food restriction and low protein diet upon collagen type I and III ratio in rat skin.

It has been demonstrated that the content of the collagen type I is more affected by both chronic low protein diet feeding and chronic food deprivation (50% food intake) than the content of collagen type III. By introducing these dietary regimes the proportion of collagen type I to collagen type III ratio drops from 2.1 to 1.3 indicating the higher proportion of collagen type III in the skin at the end of the experiment (after 18 months of chronic feeding). It was also observed that the total concentration of hydroxyproline (hyp) in the skin decreases considerably in both food restricted animals and those fed a low protein diet. It is suggested that, under the present experimental conditions, the balance between collagen break-down and synthesis is shifted and, furthermore, that this shift is different for collagen type I and III and results in an altered ratio of these two collagen species in the skin. Refeeding of animals leads to a higher than normal collagen type I to III ratio indicating thus a relatively higher proportion of collagen type I in this tissue.

Animals↗