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At least 883 records · Page 49Linked to original sources
PubMed1981

Biochemical changes in bone grafts stabilized with rigid plates. II. Cortical grafts.

The effect of rigid plate fixation on the chemical composition of cortical interposition grafts were studied in rabbit tibio-fibular bones. The concentration of hexosamines increased both in the graft and in the host bone during the first 6 weeks, but thereafter decreased. The concentrations of hydroxyproline and nitrogen increased throughout the experiment. The ratio of hexosamines to hydroxyproline increased in the graft for the first 6 weeks, indicating formation of immature osteoid and bone during this period, but thereafter decreased. The calcium concentration of the graft decreased significantly during the first 12 weeks and remained below normal (-10 to -19 per cent). The mineralization of the graft, assessed by the ratio of calcium to hydroxyproline, decreased continually. The results suggest that cortical bone grafts stabilized with rigid plates heal with only slight chemical signs of callus formation. The demineralization of the graft reflects the porotic changes that take place under the plate.

Animals↗
PubMed1982

Electrophoretic and biochemical comparison of casein and whey protein from porcine colostrum and milk.

Porcine colostrum casein contained at least one major polypeptide band in both acid gel and sodium dodecyl sulfate gel electrophoresis that did not appear in patterns of casein prepared from porcine milk. In sodium dodecyl sulfate gel patterns, this polypeptide possessed a molecular weight of 62,000 and stained positively with "Stains-all" but not with periodic acid-Schiff reagent. Several minor caseins that appeared in acid and alkaline gel patterns from colostrum could not be detected in casein prepared from milk. Seven minor polypeptides in sodium dodecyl sulfate gel patterns of whey proteins prepared from porcine colostrum could not be detected in milk. Identical acid and alkaline gel patterns were obtained for whey proteins prepared from colostrum and milk. Only the sodium dodecyl sulfate gel electrophoretic pattern of casein prepared from milk, and possibly the alkaline gel electrophoretic pattern of whey protein prepared from milk, contained polypeptides not in patterns from colostrum. Total phosphorus contents of colostrum and milk casein were 2.96% and 3.78%. Casein prepared from porcine colostrum contained almost twice as much hexosamine and slightly elevated N-acetylneuraminic acid as casein prepared from milk. Hexose content was nearly equivalent. Whey protein prepared from milk contained more total hexose than casein prepared from colostrum, whereas N-acetylneuraminic acid and hexosamine contents were nearly equivalent.

Animals↗
PubMed1989

The effect of prenatal protein-energy malnutrition on collagen metabolism in fetal bones.

We analyzed various biochemical variables of the bones in fetal rats whose dams were protein-energy malnourished. Dams were randomly divided into two groups and fed either a 6% protein diet as a malnourished group or a 20% protein diet as a control, from day 13 of gestation to day 22, when fetuses were removed. Hexosamine and hydroxyproline contents of the calvaria and hexosamine contents of long bones were greater in the malnourished group than in the controls. Sequential extractability of collagen differed among various bones in the malnourished group and controls. The ratio of alpha:beta obtained from SDS-polyacrylamide gel of neutral salt-soluble collagen tended to increase in the long bones and mandible, and decrease in the calvaria and ribs in the malnourished group. Also, the ratio of alpha 1:alpha 2 tended to be lower in the malnourished group than in the control group in all bones. Protein-energy malnutrition during pregnancy has shown to affect biochemical composition of various fetal bones.

Animals↗
PubMed1976

Chemical composition of the skeletal parts of the extremity of the adult rat following below-knee amputation and immobilisation in a plaster cast.

The chemical composition, i.e. ash and calcium contents and organic, hydroxyproline, and hexosamine contents of the acetone-dried diaphyseal cortical bone powder of the tibias and the femurs, was studied in adult rats after a) below-knee amputation and b) immobilisation of the one hind leg in a plaster cast. There were no significant differences in the chemical composition of the chemical composition of the bones of the treated extremity as compared with the corresponding bones from the non-treated control leg, either at different times after the amputation and immobilisation, respectively, or when all obtained values from each bone were tested together. The percentage hydroxyproline content of the tibia was found to be significantly higher than that of the femur in both extremities, both in the amputation and in the immobilisation experiment. The pro mille hexosamine content of the tibia, on the other hand, was significantly lower than that of the femur in both extremeities in the immobilisation experiment.

Amputation, Surgical↗
PubMed2000

Annual cyclic variations in some biochemical constituents of seminal vesicle and testis of the catfish Heteropneustes fossilis (Bloch): a study correlating plasma testosterone level.

In Heteropneustes fossilis, significant annual variations were observed in seminal vesicle-somatic index (SVSI), gonadosomatic index (GSI), concentrations of total proteins, hexosamines, fructose and glucose in both SV and testis, and in plasma testosterone with high values in late prespawning-early spawning phases (June-July) and low or undetectable levels in resting phase (December-January) except for glucose. There is an inverse relationship between the annual patterns of fructose and glucose with fructose dominant in the prespawning and early spawning phases (June-July), and glucose in the resting phase (November-January). The increase in the concentrations of SV and testicular protein, hexosamine and fructose can be correlated with the increase in testosterone concentration on one hand and with the increase of SVSI and GSI, on the other. The decrease in glucose level in the recrudescent phase may be due to its increased conversion into fructose, the main seminal sugar in this species.

Animals↗
PubMedDate not supplied

[The effect of experimental hypothyroidism in rats on the level of glycoproteins in the serum, kidneys and lungs].

The influence of the hypothyroid state (induced by dialy administration of 30 mg/100 g body wt of methyluracil, per os, for three weeks) on the perchloric acid-soluble protein level, protein-bound hexoses and protein-bound hexosamines in the blood serum, kidneys and lung tissue or rat were studied; there proved to be a statistically significant decrease in the serum and tissues of the hypothyroid rats. As to the changes in the protein-bound hexoses/protein-bound hexosamines ratio--they were not significant.

Animals↗
PubMed1975

In vitro wear of articular cartilage.

Seeking a reliable chemical index of the wear of articular cartilage during in vitro experiments, the contents of hydroxyproline, hexosamine, and the amino acid composition of adult bovine articular cartilage were determined as functions of depth from the surface. The hydroxyproline content, expressed as per cent of dry weight of tissue, was constant throughout the thickness of the tissue except in a surface region approximately twenty-five micrometers thick; the hexosamine content in this region was less than in the interior of the tissue; the collagen content was higher and the amino acid composition was less like that of pure collagen here than in the interior, indicating that the content of noncollagenous protein in the superficial layer of cartilage was greater than that in the interior. It was also evident that adult bovine articular cartilage contains significant amounts of collagen with a low hydroxylysine content, presumably Type I as well as Type II. Since the content of hydroxyproline is constant throughout the cartilage and the collagen and proteoglycan constituents of the intact tissue are relatively insoluble, the hydroxyproline content of the lubricant and the wear debris can be used to measure the extent of wear of articular cartilage during in vitro experiments. However, approximately 10 per cent of the hydroxyproline and 50 to 60 per cent of the glycosaminoglycans of the wear debris are dissolved in the lubricating fluid. Therefore, both the lubricant (solvent) and the solid wear debris must be analyzed to determine the amount of cartilage wear.

Amino Acids↗
PubMedDate not supplied

Characteristics of gastric mucus in elderly patients with gastric ulcers.

BACKGROUND/AIMS: Studies of the most important defensive factor, gastric mucus, in the treatment of gastric ulcers in elderly patients have been lacking. Therefore we focused on the changes in gastric mucus during the ulcer-healing process in elderly patients. METHODOLOGY: Twenty elderly patients (> or = 65 years old), and 20 younger patients (< 65 years old) with gastric ulcers were administered antisecretory agents for 24 weeks. Biopsies were taken from the antrum and body of the stomach, and the levels of gastric mucosal hexosamine and periodic acid-Schiff-positive gastric mucus were measured. RESULTS: In both groups, the hexosamine levels in the specimens from the body of the stomach declined during the healing process. The decrease was more marked in the elderly, and the recovery of this level was also slower than in the younger group. The periodic acid-Schiff-positive mucosal index was also lower in the elderly. A decrease in body periodic acid-Schiff-positive mucus was seen with treatment in both groups, but recovery was slower in the elderly group. CONCLUSIONS: A decrease in gastric mucus, as a gastric mucosal defensive factor, was seen in gastric ulcers in elderly patients. The potential usefulness of the administration of mucosal protective agents for elderly patients with gastric ulcers was suggested.

Adolescent↗
PubMed1976

Serum-free and protein-bound sugars and cardiovascular complications in diabetes mellitus.

Free and protein-bound serum sugars and serum lipids were analyzed in 65 adult diabetic patients, 10 age-matched controls, and 24 male medical students for correlation of carbohydrate changes with the extent of retinal, renal, and cardiovascular disease. In diabetic sera, both protein-bound sugars and free mannose, fucose, and hexosamine were significantly elevated; free galactose and inositol were elevated in some diabetic patients, and essentially undetectable in sera from controls. Serum triglycerides and pre-beta-lipoproteins were also elevated in diabetics, but alpha-lipoproteins decreased. Although no specific relationships were observed with the extent of retinal and renal disease, bivariate analyses by Pearson coefficients of correlation showed correlations between levels of serum-free mannose and systolic blood pressure, free hexosamine and duration of diabetes, and serum protein-bound fucose and age. Serum triglycerides and pre-beta-lipoprotein levels correlated with insulin therapy. These are preliminary leads of laboratory studies related to carbohydrate macromolecular changes which might aid in a better understanding of the cardiovascular complications associated with diabetes.

Adult↗
PubMed1992

[Determination of contents of glycosaminoglycans in temporomandibular joint discs in dogs].

Glycosaminoglycans (GAGs) are one of the important components of articular cartilage. The present study had determined the contents of uronic acid, galactomine, glucosamine, and hexosamine of temporomandibular joint discs in 10 dogs by Bitter's carbozole reaction method and derivative spectrophotometry. The data indicated that the contents of these components in different bands of the disc are not significantly different and that the discs of dogs contained averagely 0.6%, 0.987%, 0.4% and 1.4% of uronic acid, galactomine, glucosamine, and hexosamine respectively. The data also suggested that the discs contained keratan sulfate and chondroitin sulfate in some degree. This study is significant for analysing TMJ disc functions and its biomechanical properties in the future.

Animals↗
PubMed2005

[Establishment of an IR-HIRc cell model for screening GFAT inhibitor].

AIM: To set up an IR-HIRc cell model for screening the inhibitor of GFAT (glutamine: fructose-6-phosphate amidotransferase) , the key enzyme in the hexosamine biosynthesis pathway (HBP). METHODS: For GFAT activity assay, the GDH method was improved by adjusting the value of pH in the reaction system and the concentrations of the reactants. The sensitivity to insulin in the cells was estimated by the measurement of insulin-induced glucose-uptake. The IR-HIRc model was set up by the stimulation of long-action insulin for 36 h. The IR-HIRc model and GDH method was used for screening GFAT inhibitor. RESULTS: With the administration of 25 nmol x L(-1) long-action insulin in HIRe cells for 36 hours, the GFAT activity increased by 47% and the insulin-induced glucose-uptake decreased by 21%. Azaserine, a GFAT inhibitor, inhibited GFAT activity significantly in a dose-dependent manner in IR-HIRc model. CONCLUSION: With the stimulation of 25 nmol x L(-1) long-action insulin for 36 h, excess hexosamine flux and insulin resistant in IR-HIRc cell model was set up, which can be used for screening

Animals↗
PubMed1990

[Effect of peripheral pancreatic duct obstruction on the progression of chronic pancreatitis].

Experimental chronic pancreatitis model were made in five dogs with chronic pancreatic fistula by injection of microspheres into peripheral pancreatic duct. Sequential changes of pancreatic exocrine and endocrine functions also with morphology were studied. Significant decrease of volume, bicarbonate output, and amylase output of pure pancreatic juice (PPJ) separately collected with stimulation of secretin were detected. While, viscosity of PPJ was significantly increased with concomitant increase of hexosamine concentration. Chronic pancreatitis was demonstrated morphologically also. These results suggest that concentrated PPJ caused by decrease in volume in PPJ and increase in viscosity of PPJ with concomitant increase in hexosamine concentration bring about the progression of chronic pancreatitis in this experimental model.

Amylases↗
PubMed1988

The effect of vascularization on avian flexor tendon repair. A biochemical study.

Although it has been demonstrated in experimental animals that vascular perfusion functions less effectively than diffusion as a nutrient pathway to the uninjured flexor tendon, it is recognized that the nutritional requirements of an injured flexor tendon may be different. The present study examines several biochemical parameters of avian flexor tendon repair, during a six-week period, in the presence of an intact vinculum longum and with the vinculum longum ligated. Formation of collagen/noncollagen protein, glycosaminoglycan synthesis, and tissue levels of both DNA and hexosamine were quantified. The absence of the vincular blood supply did not affect the levels of total DNA and hexosamine, did not alter the pattern of either protein or glycosaminoglycan formation in the early healing phase, and did not impair the overall synthesis of collagen and noncollagen protein throughout the six-week study period. However, the pattern of collagen and noncollagen protein synthesis differed in lacerated tendons during the period of repair; noncollagen protein synthesis peaked at ten days, while collagen synthesis increased uniformly throughout the 42-day period of study. There was a notable decrease in total matrix hydroxyproline (collagen) during repair, which continued throughout the entire first three weeks after laceration. Thus, the actual percentage of collagen synthesis decreased during the first three weeks of repair and began to return to its normal uninjured level by the sixth week.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1977

Comparative study on the composition of the organic matrix of the long bones of the "normal" rat and of the mutant Op/Orl.

The organic matrix of the long bones of the "normal" rat strain and of its mutant Op/Orl were investigated. This latter strain exhibits some anomalles similar to Albers-Schönberg disease as well as tooth retentions. Bones (tibia, femur) were incubated with 14C-glucose and also submitted to a fractional extraction procedure (EDTA, urea) to separate soluble and insoluble fractions. The proteins, hexoses, hexosamines, hydroxyproline content of these fractions was determined as well as the radioactivity of the soluble extracts Glycosaminoglycans were also studied by cellogel electrophoresis after pronase digestion of the EDTA-extracts. Male and female animals of each strain were studied separately. The relative amount of soluble proteins (EDTA + urea extracts) was the same in both strains, the mineral content of the final residue was however higher in the mutant Op/Orl strain. The hydroxyproline content of the mutant-extracts were lower than in the original strain suggesting a lower soluble collagen content. This may be due to a faster polymerisation, insolubillisation of freshly synthesised collagen. The hexosamine content of the mutant urea extracts and the final residue was higher than that found in the analogous extracts obtained from the normal "normal" strain, suggesting a higher proportion of structural glycoproteins in the mutant bone, uronic acid being low or absent. Some other parameters were identical between the mutant and original strains but differed between males and females. The radioactivity of the soluble extracts was higher in the males than in females. The glycosaminoglycans of the EDTA extracts are also different: male-extracts show two bands on cellogel electrophoresis, one corresponding to chondroitin-sulphate, the other to hyaluronate. Females showed only the chondroitin sulphate band. The aminoacid composition of the insoluble residue of males was higher in basic amino acids (lysine, histidine, arginine) than the female extracts. These results indicate the existence of discrete well defined differences between the organic matrix of the orginal and mutant strain on one side and between male and female bones on the other side.

Amino Acids↗
PubMed1966

Abnormal gangliosides in Tay-Sachs disease, Niemann-Pick's disease, and gargoylism.

The molar ratios of N-acetyl neuraminic acid, hexose, hexosamine, and sphingosine have been determined for the abnormal ganglioside in Tay-Sachs disease that was previously detected as a fast-moving band in thin-layer chromatography, and in two abnormal fast-moving bands of gangliosides from the cortex and white matter of the brain in cases of gargoylism and Niemann-Pick's disease. The fastest-moving ganglioside band in these two conditions contains neither hexosamine nor glucose.

Amino Alcohols↗
PubMed1979

Effect of protein deficiency on the metabolism of glycoproteins and glycosaminoglycans in albino rat skin.

1. The total content of neutral sugars in skin of the weanling albino rats kept on the protein-deficient diet was increased by about 40%; this was mainly due to the increased concentration of galactose. The content of sialic acid was increased by about 20%. The collagen nitrogen was decreased significantly, with a concomitant increase of non-collagen nitrogen. At the same time, the content of sulphated glycosaminoglycans in skin was significantly decreased and that of non-sulphated glycosaminoglycans was increased. 2. Protein-deficient diet enhanced the activities of the protein-bound carbohydrate-degrading lysosomal hydrolases, viz. cathepsin D (EC 3.4.4.23), N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30) and beta-D-glucuronidase (EC 3.2.1.31) both in liver and skin. The activity of liver hyaluronidase (EC 3.2.1.35) was also increased upon limitation of protein supply. 3. The changes observed in skin were accompanied by increased concentration of the protein-bound hexoses, hexosamines and sialic acids in serum, and of hexosamine and uronic acid in urine. The serum fucose remained unchanged.

Animals↗
PubMed1983

The effect of prolonged phenytoin administration on non-collagenous components of gingival tissue.

The hyperplastic gingivae of 11 epileptic patients on prolonged phenytoin therapy and those of control patients were excised during routine periodontal surgery. The tissues were homogenized and the hexosamine, uronic acid and total protein contents were determined. It was found that the gingivae of patients on prolonged phenytoin therapy had significantly raised hexosamine, uronic acid and total protein levels as compared with the controls. However, the relative concentration of the three parameters was similar in both groups. It is suggested that the enlargement of gingival tissue observed in patients who "respond" to prolonged phenytoin treatment may be the result not only of collagen over-production but also of the elevated levels of GAG.

Adult↗
PubMed1982

[Carbohydrate content of lipoproteins after sequential precipitation with phosphotungstate magnesium chloride].

A method is described for rapid determination of protein-bound carbohydrates in human lipoproteins. The method is based on a successive precipitation of lipoproteins with sodium phosphotungstate and magnesium chloride. After purification of the separated lipoproteins by a twofold reprecipitation, a colorimetric determination of hexoses, hexosamines and N-acetylneuraminic acid (sialic acid) is performed. The coefficients of variation in the series are between 3.2% and 7.3%. The results for lipoprotein-bound carbohydrates after precipitation are compared with the corresponding values after separation by ultracentrifugation. The concentrations of hexoses, hexosamines and N-acetylneuraminic acid in the 3 lipoprotein classes VLDL, LDL and HDL of control persons are reported.

Carbohydrates↗