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Biomedical subjects

M Adam

Publications and source records attributed to M Adam.

At least 37 records · Page 2Linked to original sources
PubMed1990

The effect of liquid nitrogen submersion on cryopreserved human heart valves.

Cryopreservation and storage of human heart valves have become an accepted means of maintaining a usable supply of heart valves for outflow track reconstructive surgery. Valves are typically stored at the vapor phase temperature of liquid nitrogen, -130 degrees C and below, to reduce the chance of recrystallization within the tissues. Concern over the effects of submersion of the valves in liquid nitrogen, i.e., plunging to -196 degrees C, prompted this study. Cryopreserved valves were plunged into liquid nitrogen, held for 5 min, and then processed (thawed) by standardized protocols. The thawed valves were then assessed using scanning electron microscopy and the more traditional histology at the light microscope level. Cuspal tissues plunged into liquid nitrogen appear to have numerous microfractures over both surfaces of the tissue, penetrating into the collagen/proteoglycan matrix. Control cryopreserved valves do not exhibit these microfractures. Histologically, the submerged valves appear normal. The clinical use of valves which have been submerged in liquid nitrogen is discussed.

Cryopreservation↗
PubMed1990

Preparation of factor-VIII-depleted plasma with antibodies and its use for the assay of factor VIII.

Standardized factor VIII (FVIII)-deficient plasma is necessary for the clotting assay of this protein. Ethical considerations and prevalence of HIV seropositivity in hemophilia A patients have required the replacement of severe hemophilia A plasma by another specific substrate for FVIII clotting assays. FVIII-deficient plasma was prepared by immunodepletion using polyclonal anti-von-Willebrand factor (vWF) and monoclonal anti-FVIII antibodies coated to agarose beads. This plasma, deficient in both FVIII and vWF, allows the evaluation of FVIII activity with a detection limit of 1% as compared to normal plasma. This immunodepleted plasma was compared to plasma from severe hemophilia A for the FVIII determination in plasma from normal subjects, severe and mild hemophiliacs, patients with von Willebrand disease and dicoumarol-treated patients. In all cases, similar values were obtained with both reagents at various levels of FVIII, with a correlation coefficient of 0.994. Such a good correlation was also obtained for the assay of FVIII in concentrates and in plasma from hemophiliacs following infusion. This immunodeficient plasma thus represents a suitable reagent for the FVIII clotting assay and provides an accurate alternative to the use of hemophilic plasma.

Antibodies↗
PubMed1990

Hematopoietic stem cell potential from umbilical cord blood.

We studied the conditions of collection and isolation of hematopoietic cells from cord blood in order to optimise the sampling. A statistically significant correlation was found between the total stem cell content of the samples and the time of delivery suggesting that the quantity of hematopoietic stem cells available is higher when cord blood collection is performed earlier during pregnancy. Attempt to isolate the white cells resulted in a dramatic loss of stem cells. Factors affecting cell recovery and purification must be investigated in order to optimize cord blood cell banking.

Blood Specimen Collection↗
PubMed1990

Comparison of the influence of gelatine and collagen substrates on growth of chondrocytes.

The effect of culture substrates on adhesion and growth of chondrocytes and the influence of varying amounts of foetal calf serum on cell proliferation are compared. Skin and cartilage gelatines and type II collagen were used as substrates. The cells used in the experiments were the primary cultures of chondrocytes, frozen primary cultures of chondrocytes and chondrocytes after the 1st subculture. Cartilage gelatine had a more marked influence on cell proliferation than skin gelatine, especially in primary cultures. The differences were off in cells after the 1st subculture. Differences in the number of cells are evident also after decreasing the serum concentration in culture medium.

Animals↗
PubMed1989

Separation of collagens by capillary zone electrophoresis.

Collagen (types I, II, V, IX and XI) constituting polypeptide chains and their polymers and cyanogen bromide-cleaved peptides of collagen type I and type III were investigated by means of capillary zone electrophoresis. Separations were effected in 2.5 mM sodium tetraborate buffer in less than 15 min. A 50 cm x 0.1 mm I.D. fused-silica capillary was used. The separations were run at 18 kV per capillary. The results of the separation were monitored at 220 nm with an on-tube detection system. Using the Offord equation, relative retention times of cyanogen bromide cleavage fragments were plotted against M(2-3)/Z, where M is the molecular mass of a polypeptide and Z its valency. A linear relationship was observed. Collagen alpha-chains and their polymers were also satisfactorily resolved.

Collagen↗
PubMed1989

[Collagen as a biomaterial].

The authors discuss the characteristics of different types of collagen, their incidence, structure, chemical composition and physical properties with regard to their use as biomaterial. They also mention the antigenicity, effect on platelet aggregation, cytodifferentiation and cellular proliferation. The authors discuss different biomedical applications of collagen and methods of its sterilization.

Biocompatible Materials↗
PubMed1989

Markers of collagen metabolism in sera of patients with various rheumatic diseases.

The activity of galactosylhydroxylysyl glucosyltransferase (S-GGT) and concentration of the amino-terminal propeptide of type III procollagen, measured with two different radioimmunoassays, S-Pro(III)-N-P and S-Fab, were determined in the sera of 209 patients with various rheumatic diseases. The mean values for all these three assays were elevated in the patients with rheumatoid arthritis, whereas only the mean value for S-GGT was elevated in osteoarthrosis. The mean S-GGT but not S-Pro(III)-N-P or S-Fab was also elevated in psoriatic arthritis, ankylosing spondylitis and systemic lupus erythematosus. S-GGT correlated significantly both with S-Pro(III)-N-P and S-Fab in the pooled group of all the patients and in the cases of rheumatoid arthritis and psoriatic arthritis, and also with S-Fab in the cases of osteoarthrosis. S-Pro(III)-N-P and S-Fab correlated with each other in every disease group. The ratio S-Fab:S-Pro(III)-N-P was significantly higher in the patients with osteoarthrosis, ankylosing spondylitis and systemic lupus erythematosus than in those with rheumatoid arthritis. The data indicate that definite changes can be seen in the values of serum markers of collagen metabolism in rheumatoid arthritis, psoriatic arthritis, osteoarthrosis, ankylosing spondylitis and systemic lupus erythematosus, the most sensitive indicator being S-GGT.

Adult↗
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↗