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Biomedical subjects

M Adam

Publications and source records attributed to M Adam.

At least 127 records · Page 7Linked to original sources
PubMed1989

Separation methods for the study of collagen and treatment of collagen disorders.

Liquid chromatographic and electrophoretic methods applicable to the separation of collagen and its fragments are reviewed. Special attention is paid to the separation of both stabile and labile crosslinking elements. Identification procedures exploiting the mapping of either collagen alpha-chains or of cyanogen bromide fragments are discussed. These methods can be used for diagnosing inborn errors of collagen metabolism using bioptic or necroptic samples. Analysis of urinary hydroxyproline-containing peptides or the determination of peptidically bound pyridinoline is suitable for measuring the intensity of collagen metabolism.

Amino Acids↗
PubMed1989

Determination of radiolabelled proline and hydroxyproline in collagen hydrolysates by high-performance liquid chromatography with on-line radiometric detection.

Radiolabelled proline and hydroxyproline were separated on a C8 column (10 cm X 4.6 mm I.D.) with 10.4 mM sodium dodecyl sulphate in water-n-propanol (88:12, v/v) (pH 2.6) as the mobile phase at a flow-rate of 0.6 ml/min. The retention times of hydroxyproline and proline were 5 and 8 min, respectively. On-line radiometric detection was performed either in a homogeneous mode (liquid scintillator was added to the column effluent in the ratio 3.33:1) or in a heterogeneous mode (the detection cell was packed with a solid scintillator and 0.1 M ammonia was mixed with the column effluent in the ratio 1:6 in order to prevent adsorption of amino acids on the cell packing). Detection limits were in the range 100-900 dpm for individual isotopes and detection modes and the reproducibilities were better than 10%. The application of the method to a collagen synthesis study is reported.

Chromatography, High Pressure Liquid↗
PubMed1989

[Experimental models of arthritis induced by various cartilage collagen type].

To laboratory rats of Wistar strain (Ipcv: Wist) native collagenous types of pig cartilage--II, IX and XI and the denatured type XI were administered. The first immunization dose, 0.5 mg collagen per experimental animal, was administered in incomplete Freund adjuvant and the second immunization dose (collagen in solution) followed after 7 days and was administered by the i.p. route. Inflammatory arthritis of the small interphalangeal, metatarsophalangeal and tarsal joints developed between the 11th and 17th day of the experiment in rats immunized with native collagen type II and XI--60% of the animals were affected. The histological findings corresponded to the course of arthritis, however, the articular destructive changes after administration of collagen type XI were more severe than after type II. The changes were evaluated by X-ray and by means of thermovision. The antibody levels against different types of collagen assessed by means of the ELISA test reached peak values between the 13th and 20th day of the experiment. In the group of rats immunized by collagen type IX and the denatured type XI arthritis did not develop. The antibody response in the group of rats immunized with type IX was similar as in the group immunized with types II and XI. Histological examination confirmed some changes in the joints of rats immunized with collagen type IX, while in the joints of rats immunized with denatured collagen type XI no changes were found.

Animals↗
PubMed1989

[The effect of a gold complex on experimental arthritis induced by immunization with type II collagen].

Gold complexes are used in the treatment of rheumatoid arthritis for some 60 years by now. The authors used therefore a gold complex, sodium aurothiosulphate (ATSS) to influence the experimental model of arthritis induced by immunization with type II collagen in laboratory rats. To the first group of laboratory rats ATSS was administered concurrently with the first immunization dose, to the second group with the second immunization dose and to the third group in the course of arthritis. ATSS was administered to individual groups every week by the i. m. route, 20 mg/kg body weight. In all three groups a reduction of arthritic symptoms was observed, however, in group three to a much lesser extent than in groups one and two. The results of the experiment indicate clearly that ATSS was able to suppress the development of collagen induced arthritis, if administered not later than with the second immunization dose. As the formation of antibodies against type II collagen was not suppressed, it may be assumed that the activation of the complement system was blocked by the bond of the gold complex with the C1q component. It has been proved already previously that the interaction of C1q with gold complexes is very rapid.

Animals↗
PubMed1989

[The development of osteoarthrosis and the role of collagen in the pathophysiology of its development].

The work deals with the structure, chemical composition and physical properties of individual types of collagen of which thirteen has been so far described. Special attention is devoted to the types of collagen II, VI, IX and XI which are found in the articular hyaline cartilage. The main collagen type of the articular cartilage is type II which makes up approximately 90 per cent of all the collagen. The remaining three types fall into the so called minority types. Collagen of type IX differs from other types by the kink in its structure. This type of collagen represents a certain transition to proteoglycans with regard to the fact that the lateral glycoaminoglycan chain is attached. The work is supplemented with electron microscope pictures of individual molecules of these types. It describes also individual stages of biosynthesis and special attention is devoted to the aggregation of molecules into fibrils. The authors describe the cross-linking elements of lysinonorleucine and pyridinoline type. The changes which occurring in the structure and metabolism of collagen in the course of osteoarthrosis are described. The role of adhesive proteins is mentioned and the influence of the osteoarthrotic changes on nutrition and its function as well as on the development of pathogenetic mechanism is described.

Collagen↗
PubMed1989

[The incidence of antibodies against collagen in patients with juvenile chronic arthritis].

Using the ELISA method, the authors assessed titres of antibodies to collagen type I, II and III in serum of patients with juvenile chronic arthritis (JCA). The results were compared with antibody titres in patients with rheumatoid arthritis (RA). Elevated antibody titres to all collagen types were found, as compared with age-matched controls. The mean titres in patients with RA were higher than in the group with JCA. Investigation of a correlation between the collagen antibody titres and values of the sedimentation rate after one hour revealed a statistical relationship only in collagen type II in patients with RA.

Adolescent↗
PubMed1989

[Comparison of 2 methods for determining antibodies to collagen: the ELISA test and passive hemagglutination].

For the determination of antibodies against collagen in different rheumatic diseases the authors elaborated two serological techniques. It was particularly the passive haemagglutination, which proved to be little sensitive and insufficiently reproducible. Therefore, for the determination of antibodies against collagen the authors introduced the ELISA method as one of the varieties of enzyme immunoanalysis, giving more precise results. Both methods were compared and it has become apparent that the ELISA method is more reliable and more suitable for the determination of antibodies against collagen.

Autoantibodies↗
PubMed1988

Separation of type IX collagen from other cartilage collagens by hydrophobic interaction chromatography.

Collagen type IX was separated from other cartilage collagens (types II and XI) by hydrophobic interaction chromatography on a 25 cm X 8 mm I.D. stainless-steel column packed with Separon HEMA 1000 Bio. The mobile phase was 0.84 M ammonium sulphate with 0.1 M potassium dihydrogenphosphate (pH 6.5). Under these conditions only collagen type IX was eluted from the column; it could be monitored with UV detection (218 nm) or selectively with fluorescence detection (excitation 330 nm, emission filter 389 nm). The method can be used for the isolation and quantitation of collagen type IX. The assay was linear in the range 0-10 micrograms, the correlation coefficient was 0.99, precision 5.5% and accuracy 13%. The detection limit was about 0.6 microgram.

Animals↗
PubMed1988

Incorporation of myristate and palmitate into the sheep reticulocyte transferrin receptor: evidence for identical sites of labeling.

The ability of sheep reticulocytes and plasma membranes isolated from them to incorporate fatty acids into the transferrin receptor has been examined using both [3H]palmitate and [3H]myristate. Both fatty acids, when incorporated into the transferrin receptor, can be released by treating the protein with 1 M hydroxylamine at pH 7.0. After treatment of the 3H-acylated receptor with borohydride, an 3H-labeled alcohol is released, suggesting that the receptor-bound fatty acid is in thioester linkage. With both [3H]myristate and [3H]palmitate, Cleveland maps from immunoprecipitates of the transferrin receptor labeled in intact cells and isolated membranes show that identical peptides are labeled. No evidence was obtained for qualitatively different labeling with the two fatty acids. In intact reticulocytes, incorporation of [3H]palmitate into the transferrin receptor is approximately 3.5 times greater than the incorporation of [3H]myristate from equivalent concentrations of the labeled fatty acids. However, in isolated reticulocyte plasma membranes, there is much less difference between palmitate and myristate incorporation (with ATP) or between their acyl-CoA derivatives. The reason for the discrepancy between cells and membranes is unknown but may be due to the presence in intact cells of more than one enzyme for activating the fatty acids. Acylation of the receptor in isolated plasma membranes is fourfold greater with the CoA derivatives than with the free fatty acids. The fatty acid activating enzyme(s) as well as the acyltransferase(s) appear to be membrane bound in reticulocytes.

Acylation↗
PubMed1988

Anticollagen antibodies in patients with juvenile chronic arthritis.

Using ELISA antibodies, titres to collagen type I, II and III in sera of patients with juvenile chronic arthritis (JCA) were assayed. Results were compared with titres of patients with rheumatoid arthritis (RA). Increased antibodies titres to all three collagen types were found in comparison with healthy individuals of the same age. Average titres in patients with RA were higher than those of the JCA group. When antibodies titres were correlated with erythrocyte sedimentation rate in 1 hour (ESR/1h) statistical significance was found only in RA group for collagen type II.

Adolescent↗
PubMed1988

Regional cerebral glucose metabolism in identical twins.

The present study reports on the degree of similarity in regional cerebral glucose metabolism in seven sets of female identical twins. All scans were done with subjects at rest. Glucose metabolism was measured with positron emission tomography (PET). Significant intraclass correlations were found for the orbital and prefrontal cortex as well as the basal ganglia (caudate/putamen). It is suggested that these correlations reflect the functional aspects of these areas, namely attention and posturing movements.

Adult↗
PubMed1988

Changes in type V collagen in the kidneys of DOCA-NaCl treated rats.

Type V collagen was extracted and quantitated in the kidneys of unilaterally nephrectomized rats exposed to desoxycorticosteron acetate (DOCA-NaCl) treatment. A highly elevated content of collagen type V was found in these kidneys compared with controls. A higher content of collagen type V was present both in the pepsin digest of the total kidney and in the isolated glomerular basement membranes. It was previously reported that one of the factors involved in the growth of the remaining kidney in unilaterally nephrectomized DOCA-NaCl treated rats is the increase of collagen type IV, the effect being more prominent in rats nephrectomized at a younger age. The present study documents that the increase of type V collagen follows the same pattern.

Animals↗
PubMed1987

Altered metabolism of [18F]-6-fluorodopa in the hooded rat following inhibition of catechol-O-methyltransferase with U-0521.

[18F]-6-Fluoro-L-DOPA ([18F]DOPA), a tracer for cerebral dopamine in studies utilizing positron emission tomography (PET), is rapidly metabolized by catechol-O-methyltransferase (COMT) in the periphery following intravenous injection to carbidopa-pretreated humans and rats. Experiments were performed to determine the effect of pretreatment with 3',4'-dihydroxy-2-methyl-propiophenone (U-0521), a competitive inhibitor of COMT, on [18F]DOPA metabolism in the carbidopa-pretreated hooded rat. U-0521 (25 mg/kg, i.p.), administered 10 min prior to the [18F]DOPA, served to increase the persistence of [18F]DOPA in plasma over a 2-hr period by decreasing the rate of formation of the peripheral metabolite 3-O-methyl-6-fluorotyrosine (Me[18F]DOPA). This compound passes readily into brain and was the sole [18F]DOPA metabolite observed in cortex and cerebellum. U-0521 produced a short-lasting decrease in Me[18F]DOPA levels in these two tissues. In striatum, decreases in Me[18F]DOPA were found to last at least 90 min. Associated with the elevated availability of [18F]DOPA in plasma produced by U-0521 were 50% increases in striatal [18F]dopamine ([18F]DA) levels and 40% increases in the levels of [18F]dihydroxyphenylacetic acid ([18F]DOPAC) at times between 30 and 90 min following [18F]DOPA injection. Increased decarboxylation of [18F]DOPA in the striatum of U-0521-treated rats resulted in heightened radiocontrast between striatum and other cerebral tissues.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1987

Vesicle formation during reticulocyte maturation. Association of plasma membrane activities with released vesicles (exosomes).

Vesicles are released during the in vitro culture of sheep reticulocytes which can be harvested by centrifugation at 100,000 X g for 90 min. These vesicles contain a number of activities, characteristic of the reticulocyte plasma membrane, which are known to diminish or disappear upon reticulocyte maturation. The activities include acetylcholinesterase, cytochalasin B binding (glucose transporter) nucleoside binding (i.e. nucleoside transporter), Na+-independent amino acid transport, and the transferrin receptor. Enzymes of cytosolic origin are not detectable or are present at low activity in the vesicles. Cultures of whole blood, mature red cells, or white cells do not yield comparable levels of these activities, supporting the conclusion that the activities arise from the reticulocytes. In addition, the lipid composition of the vesicles shows the high sphingomyelin content characteristic of sheep red cell plasma membranes, but not white cell or platelet membranes, also consistent with the conclusion that the vesicles are of reticulocyte origin. It is suggested that vesicle externalization may be a mechanism for shedding of specific membrane functions which are known to diminish during maturation of reticulocytes to erythrocytes.

Acetylcholinesterase↗
PubMed1987

Calcification of poly(2-hydroxyethyl methacrylate)-collagen composites implanted in rats.

Samples of the polyHEMA-collagen composites with varying collagen content have been implanted into the popliteal region of rats. Three, six and twelve months after the implantation, calcification of the implanted material was determined using a radioactive indicator. At the same time, the implants and surrounding tissue were examined histologically. The degree of calcification of the implants was dependent on the collagen content; it was more pronounced with a higher amount of collagen. The composites with 30% (w/w) or more collagen were biodegraded during the long-term implantation. It is suggested that the composites containing less than 20% (w/w) of fibrillar collagen are used for biomedical applications and that those with a higher collagen content for the in vitro studies.

Animals↗