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At least 307 records · Page 17Linked to original sources
PubMed1999

Influence of different exercise levels and age on the biochemical characteristics of immature equine articular cartilage.

This study aimed to examine whether biochemical characteristics of juvenile articular cartilage are changing during the first year post partum and whether they can be influenced by exercise at young age. Water, glycosaminoglycan (GAG), DNA, total collagen, hydroxylysine and hydroxylysylpyridinoline (HP) content were measured in articular cartilage of 43 foals that were subdivided into 3 groups (n = 15, 14 and 14) which were subjected to different exercise regimens from one week after birth to age 5 months. At the age of 5 months all foals were weaned and 8 foals were selected randomly from each exercise group and subjected to euthanasia. The remaining foals (n = 19) were grouped and subjected to a similar exercise regimen for an additional 6 months. Differences were tested by student's t test (P<0.01). No effect of exercise on the water or DNA content was found. GAG content increased with increasing exercise in the 5 months group. These differences had disappeared after 6 months of similar exercise. No influence of exercise could be demonstrated on any of the collagen parameters. When comparing 5 months with 11 months group, all parameters except hydroxylysine changed significantly during these 6 months. Water, DNA and GAG content decreased during maturation. Collagen and HP content increased. It is hypothesised that juvenile equine articular cartilage may be seen as a dynamic, continuously remodelling tissue that is gradually taking on the biochemical characteristics it will have during the rest of the life of the animal. Moderate exercise does not influence the collagen component of the extracellular matrix. It has a beneficial, but reversible, effect on the glycosaminoglycan component.

Aging↗
PubMed1980

Comparison of the chemical and polypeptide composition of tubular and glomerular basement membranes.

Renal tubular and glomerular basement membranes were isolated from rabbit, rat and mouse kidneys. Methods were developed to obtain the basement membrane from limited numbers of animals. Rabbit and mouse tubular basement membrane as well as rabbit and rat glomerular basement membrane were obtained from single animals in quantities sufficient for electrophoresis and chemical analysis. The chemical composition of all the basement membranes were compared and sodium dodecylsulfate-polyacrylamide gel electrophoresis was performed on rabbit tubular and glomerular basement membranes in order to compare their polypeptide composition. The chemical composition of the tubular basement membranes were similar, each species having nearly equal concentrations of glycine, hydroxyproline and hydroxylysine, respectively. Glomerular basement membranes were also similar to each other and close to tubular basement membranes in chemical composition. Within each species, the glycine, hydroxyproline and hydroxylysine values for tubular basement membrane were about 10% higher than for glomerular basement membrane. The polypeptide composition of a reduced, sodium dodecylsulfate-soluble fraction of the rabbit basement membranes appeared to be alike with two exceptions. A prominent band of Mr = 160,000 seen in gels of tubular basement membrane was present as a lightly staining band in glomerular basement membrane samples and a prominent band of Mr = 140,000 in gels of glomerular basement membrane was seen as a light band in samples of tubular basement membrane.

Animals↗
PubMed1990

Hydroxylation of collagen by lungs of rats administered bleomycin.

Collagen synthesized by tissue minces from lungs of rats administered 1 unit of bleomycin by intratracheal instillation 1 or 2 wk earlier contained relatively more hydroxylysine than did collagen made by lungs from saline-instilled control animals. Most, if not all, of the relative increase in lysine hydroxylation could be localized to the alpha 1 (I) chain of type I collagen. Lung homogenates from bleomycin-treated rats showed increased activity of lysyl hydroxylase (EC 1.14.11.4), the enzyme catalyzing the conversion of collagen-bound lysine to hydroxylysine. Thus, the increased hydroxylation of lysine and of lysine-derived cross-links previously observed in collagen of diseased human lungs and in animal models of lung fibrosis is reflected in an in vitro system.

Animals↗
PubMed2006

Glycosylation catalyzed by lysyl hydroxylase 3 is essential for basement membranes.

Lysyl hydroxylase 3 (LH3) is a multifunctional enzyme possessing lysyl hydroxylase (LH), hydroxylysyl galactosyltransferase (GT) and galactosylhydroxylysyl glucosyltransferase (GGT) activities in vitro. To investigate the in vivo importance of LH3-catalyzed lysine hydroxylation and hydroxylysine-linked glycosylations, three different LH3-manipulated mouse lines were generated. Mice with a mutation that blocked only the LH activity of LH3 developed normally, but showed defects in the structure of the basement membrane and in collagen fibril organization in newborn skin and lung. Analysis of a hypomorphic LH3 mouse line with the same mutation, however, demonstrated that the reduction of the GGT activity of LH3 disrupts the localization of type IV collagen, and thus the formation of basement membranes during mouse embryogenesis leading to lethality at embryonic day (E) 9.5-14.5. Strikingly, survival of hypomorphic embryos and the formation of the basement membrane were directly correlated with the level of GGT activity. In addition, an LH3-knockout mouse lacked GGT activity leading to lethality at E9.5. The results confirm that LH3 has LH and GGT activities in vivo, LH3 is the main molecule responsible for GGT activity and that the GGT activity, not the LH activity of LH3, is essential for the formation of the basement membrane. Together our results demonstrate for the first time the importance of hydroxylysine-linked glycosylation for collagens.

Animals↗
PubMed1985

Studies on amino acid composition of renal glomeruli from the diabetics.

Amino acid analysis was carried out on the acid hydrolyzate of the glomeruli isolated from the kidneys of 19 nondiabetic and 21 diabetic autopsy subjects. The glomeruli isolated from the diabetics were found to have a significant increase in their contents of amino acids such as hydroxyproline, glycine and hydroxylysine, when compared with nondiabetic controls. These changes were detected already in the diabetic cases with no apparent histological change, and were prominent in the glomeruli which had nodular lesion. A linear relationship was evident between the contents of hydroxyproline and hydroxylysine in the glomeruli isolated from all 40 subjects studied (y = 9.50 + 4.88x, r = 0.918, p less than 0.001). The values for the diabetic glomeruli showing diffuse lesion and nodular lesion scattered continuously along the same line. These results suggest that chemical character is almost same in the diabetic glomeruli with either diffuse lesion or nodular lesion.

Aged↗
PubMed1982

Lens capsule basement membrane synthesis. Stimulation by glucose in vitro.

To examine the question of whether hyperglycemia per se can affect basement membrane synthesis, intact rat lenses, which produce basement membrane in vitro, were incubated for 24 h with radioactive proline or lysine and varying concentrations of glucose. Lens capsule basement membrane (LCBM) was subsequently purified and analyzed for radiolabel incorporation and for specific activities of proline, hydroxyproline, lysine, and hydroxylysine. [14C]-proline and lysine incorporation into LCBM was increasingly stimulated in incubations performed with 10 and 20 mM compared with 5 mM glucose. High glucose concentration increased the specific activity of proline and lysine but not hydroxyproline or hydroxylysine, and decreased the ratio of radioactive hydroxyproline to proline. Gel electrophoresis of radiolabeled LCBM prepared after high glucose incubation revealed increased radioactivity in serveral high-molecular-weight components corresponding with the major Coomassie-blue peptide bands. The results indicate that glucose stimulates LCBM synthesis, and suggest that this effect derives from increased production of noncollagenous components.

Animals↗
PubMed1975

Chemical characterization of new antibiotics, cerexins A and B. (Studies on antibiotics from the genus Bacillus. II)

Acid hydrolysis revealed that the antibiotic cerexin A is constructed with aspartic acid (3), threonine (1), serine (1), valine (2), allo-isoleucine (1), gamma-hydroxylysine (1), tryptophan (1), and a variety of fatty acid residues. The essential difference between cerexins A and B is concluded to be replacement of serine and one valine residue in cerexin A by glycine and phenylalanine in cerexin B. Isolation of a new amino acid L-threo-gamma-hydroxylysine is also described.

Anti-Bacterial Agents↗
PubMed1975

Studies of the capillary basal lamina. II. Preparation, chemical composition, andmetobolic properties.

Large amounts of basal laminae material can be extracted by sonic disruption from the capillary tissue of the rete mirabile of the eel swimbladder. The extracted basil laminae material has the same fibrillar pattern as that found in the intact tissue. Thechemical composition is similiar to that of other basil laminae isolated from tissues inmammals, with high content of glycine, proline, hydroxyproline, lysine, and hydroxylysine. The mono- and disaccharide units linked to the hydroxylysine are also present. Of all the pathways of glucose utilization, the 'C-glucose incorporation into the basallamina glycoproteins is the most sensitive to the medium glucose concentration. The glucosyltransferase activity seems stimulated to a plateau value of saturation when the medium glucose concentration is raised from 5 to 20 mm. The 'C-labeled amino acid incorporation into the basal laminae glycoproteins is not affected bythe medium glucose concentration. The results obtained in this study allow for a hypothesis which links the biochemical, morphologic, and functional properties of various typesof basal laminae in normal and hyperglycemic conditions.

Air Sacs↗
PubMed2001

[Bone complication in diabetes subjects with good metabolic control and without longterm complications: certain problems. Part II. Basal parameters of bone turnover].

The resorption and osteogenesis equilibrium is commonly known basal condition of bone tissue homeostasis. For the purpose of bone turnover analysis in the group of good controlled diabetic patients without any diabetic complications basal biochemical parameters of osteogenesis and resorption were estimated. During low-calcium diet conditions both serum concentration and urine excretion of creatinine, hydroxyproline, hydroxylysine and uric acid were investigated. Serum alkaline phosphatase activity and oxalic acid urine excretion were also measured. As the result of the study the higher serum alkaline phosphatase activity and hydroksyproline urine excretion in type 1 diabetic patients as well as higher hydroxyproline and hydroxylysine urine excretion in type 2 diabetic patients were found.

Alkaline Phosphatase↗
PubMed1992

A study of osteoporosis as it relates to metabolic manifestations in edentulous women.

Among some patients, regardless of age, the jaw loses bone mass, leading to loosening and falling out of otherwise healthy teeth. This study seeks to establish whether this bone loss is associated with the metabolic manifestations of other forms of localized decalcifications, such as in Paget's disease, or with generalized osteoporosis. Sixteen women being fitted with dental implants to compensate for bone losses provided 24-hour urine samples for the quantitative determination of calcium and galactosyl hydroxylysine, a bone collagen metabolite. These patients provided demographic information, relevant medical, dental, and dietary history, a profile of their current medications, and the status of their smoking and exercise habits. Urinary excretion of galactosyl hydroxylysine, which is increased in the presence of progressive increased bone resorption, remained within normal values in the patients of this study. These results suggest that the thinning of the jaw bones and subsequent tooth loss of these subjects were osteoporotic processes too limited and too localized to produce measurable increases in urinary bone metabolites.

Adult↗
PubMed1978

Biochemical studies on glomerular basement membrane in human diabetic microangiopathy.

Biochemical modifications of glomerular basement membrane (GBM) in diabetes mellitus have been investigated in human subjects. Amino acid analysis and electrophoretic study of unfractioned GBM from diabetic and non diabetic kidneys showed an increase in hydroxylysine, hydroxyproline and glycine and in the glycosylgalactosyl-hydroxylysine (G-G-H) content of diabetic GBM. A decrease in 1/2 cystine was also demonstrated in diabetes. Fractionation of GBM showed the increase in G-G-H observed on unfractioned GBM to reflect a quantitative increase of the "collagen" fraction in diabetes, the amino acid composition of this fraction remaining unchanged. The decrease in 1/2 cystine demonstrated on unfractioned GBM was located in the non collagenous fractions of this structure.

Amino Acids↗
PubMed1977

The effect of cytostatic drugs on collagen metabolism in guinea pigs.

Azathiprine (0.25 mg/100 g body wt.) and cyclophosphamide (0.2 mg/100 g body wt.) were administered to guinea pigs, orally every day during 4 weeks. Azathioprine caused a decrease in total collagen content in skin, liver and bone and decreased hydroxyproline and hydroxylysine concentration in blood serum, and urinary excretion of collagen catabolites. No effect of cyclophosphamide on total collagen in skin and liver was observed. An increase in collagen content in bone in cyclophosphamide-treated guinea pigs was found. A decrease of hydroxyproline and hydroxylysine in blood serum and urine was observed after cyclophosphamide treatment. The results support the view that cytostatic drugs inhibit collagen metabolism, and azathioprine significantly affects collagen biosynthesis, and cyclophosphamide influences inhibition of catabolic processes of collagen.

Animals↗
PubMedDate not supplied

Biochemical analysis of rabbit articular cartilage using an amino acid analyzer.

The automated amino acid analyzer has been used to provide a simple, rapid and accurate means of assaying the glycosaminoglycan (GAG) and collagen content, and collagen type of connective tissues. The analysis of rabbit articular cartilage using this method is reported. Cartilage slices taken from the tibial plateaus of rabbits were dried and weighed. A comparison study showed that oven-drying (110 degrees C for 24 hours) was more effective in dehydrating cartilage than vacuum dessication for 96 hours. This drying temperature could be maintained for 24 hours without destroying hexosamine. The dried samples were hydrolyzed for 4 hours in 4 N HCl at 100 degrees C; these conditions were shown to give virtually 100% release of galactosamine from purified chondroitin-6-sulphate with minimal degradation of the hexosamine. The 4-hour hydrolysates were assayed for galactosamine and glucosamine using the amino acid analyzer. From these values the amount of chondroitin sulphate and keratan sulphate were calculated. An aliquot of the 4-hour hydrolysate was hydrolyzed further in 6 N HCl for 24 hours. This destroyed hexosamine but permitted the quantitation of hydroxyproline and hydroxylysine using the amino acid analyzer. Collagen content was calculated from the hydroxyproline value and the hydroxylysine to hydroxyproline ratio was used to determine the collagen type.

Amino Acids↗
PubMed1982

Collagen metabolism in patients with myocardial infarction.

The healing of myocardial infarction is accompanied by an increased accumulation of collagen in the heart muscle. Indexes of collagen metabolism (serum hydroxyproline, hydroxylysine and collagen-like protein concentration) were measured in 60 patients with myocardial infarction and 30 healthy blood donors. Determinations were carried out 1, 2, 3 days after admission and between the 10th-14th and 21st-25th day of the illness. It was found that hydroxyproline and hydroxylysine decreased in the first days of the disease, and subsequently increased in the course of the healing process accompanied by an increased collagen-like protein level. The changes did not depend on the total protein concentration.

Adult↗
PubMed1980

[The biochemical changes of bone collagen after high-dose irradiation (author's transl)].

In our clinic, patients with malignant bone tumors have been treated by high-dose irradiation therapy, 10,000-20,000 rads, for primary lesions. In order to study the biochemical changes of normal bone around tumor tissue, especially bone collagen, after high-dose irradiation, the author performed the following experiments. The right knee joint of rabbits was irradiated with either 6,000, 10,000, or 15,000 rads by 60Co-gamma ray. The cortical bone of the right tibial metaphysis was used for analyses and compared with the left tibia of the same rabbit. These studies were followed for one year after the final irradiation. The calcium, phosphorus and collagen contents of irradiated bone were remarkably changed. These data indicate that collagen biosynthesis of irradiated bone was decreased and the calcification was disturbed. An increase in the amount of total soluble collagen and a decrease in the amount of hydroxylysine bound sugar were observed. The ratio of beta to alpha chains of the collagen molecule was also changed by the irradiation. The amount of reducible cross-links per hydroxyproline residue was strikingly increased three months after the final irradiation. These changes were remarkable especially in the 10,000 and 15,000 rads irradiated group and found to be recovered approximately six months to one year after the final irradiation. These findings indicate that high-dose irradiation reduces the stability of bone collagen both with the destruction of sugar bonds of hydroxylysine residues and the replacement of matured collagen matrix to immatured one which contain mostly labile reducible cross-links.

Animals↗
PubMed1993

Biochemical markers for detecting bone metastases in patients with breast cancer.

A study was carried out to assess the best use of biochemical bone markers to exclude metastases in patients with breast cancer. Urinary galactosyl-hydroxylysine and serum alkaline phosphatase were used to monitor bone resorption and deposition, respectively. Hydroxyproline was also measured. In a selected population of patients, possibly affected by metastases on the basis of scintigraphic examination, which is highly sensitive but poorly specific, we assessed the efficiency of the markers by a double statistical analysis. In this group, the only marker able to predict metastases was galactosyl-hydroxylysine.

Alkaline Phosphatase↗
PubMed1997

Abnormal formation of collagen cross-links in skin fibroblasts cultured from patients with Ehlers-Danlos syndrome type VI.

Ehlers-Danlos syndrome type VI (EDS VI) is an autosomal recessive disorder of connective tissue characterized by hyperextensible, friable skin and joint hypermobility. Severe scoliosis and ocular fragility are present in some patients. This disease is caused by defective collagen lsyl hydroxylase, a vitamin C-dependent enzyme that converts lysyl residues to hydroxylysine on procollagen peptides. Hydroxylysine is essential for the formation of the covalent pyridinium cross-links pyridinoline (Pyr) and deoxypyridinoline (Dpyr), among mature collagen molecules. Pyr derives from three hydroxylysyl residues, whereas Dpyr derives from one lysyl and two hydroxylysyl residues. Patients with EDS VI have high urinary excretion of Dpyr, resulting in a high ratio of Dpyr-Pyr. In this study, we evaluate content and production of pyridinium cross-links in the skin and cultured fibroblasts from patients with EDS VI. The skin of normal controls contained both Pyr and Dpyr, with a marked predominance of Pyr as observed in normal urine. The skin of patients with EDS VI had reduced total content of pyridinium cross-links, with the presence of Dpyr but not Pyr. Long-term cultures of control fibroblasts produced both Pyr and Dpyr, with a pattern resembling that of normal skin. By contrast, cross-links were not detected in dermal fibroblasts cultured from patients with EDS VI. Vitamin C, which improves the clinical manifestations of some patients with EDS VI, decreased Dpyr accumulation though only minimally affecting Pyr content in control cells. By contrast, addition of vitamin C to fibroblasts from patients with EDS VI stimulated the formation of Dpyr more than that of Pyr and greatly increased total pyridinium cross-link formation. These results indicate that qualitative and quantitative alterations of pyridinium cross-links occur in skin and in cultured dermal fibroblasts of patients with EDS VI and may be responsible for their abnormal skin findings. The vitamin C-stimulated production of Dpyr and Pyr in fibroblasts from patients with EDS VI may explain at least in part the therapeutic effects of this vitamin in EDS VI.

Adolescent↗
PubMed2005

The major T cell epitope on type II collagen is glycosylated in normal cartilage but modified by arthritis in both rats and humans.

Type II collagen (CII) is a target for autoreactive T cells in both rheumatoid arthritis and the murine model collagen-induced arthritis. The determinant core of CII has been identified as CII260-270, and the alteration of this T cell epitope by posttranslational modifications is known to be critical for development of arthritis in mice. Using CII-specific T cell hybridomas we have now shown that the immunodominant T cell epitope in the normal (healthy) human and rat joint cartilage is O-glycosylated at the critical T cell receptor recognition position 264 with a mono- or di-saccharide attached to a hydroxylysine. In contrast, in the arthritic human and rat joint cartilage there are both glycosylated and non-glycosylated CII forms. Glycosylated CII from normal cartilage could not be recognized by T cells reactive to peptides having only lysine or hydroxylysine at position 264, showing that antigen-presenting cells could not degrade the O-linked carbohydrate. Thus, the variable forms of the glycosylated epitope are determined by the structures present in cartilage, and these vary during the disease course. We conclude that the chondrocyte determines the structures presented to the immune system and that these structures are different in normal versus arthritic states.

Amino Acid Sequence↗