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PubMed1990

A screening method for mucopolysaccharidoses with increased urinary excretion of sulfated N-acetylhexosamines.

Patients with mucopolysaccharidosis have been reported to excrete elevated amounts of sulfated N-acetylhexosamines in their urine. Based on this finding, a new and simple colorimetric screening test for these disorders is presented. Chromatography of whole urine on Dowex AG 1-X8, from each of 23 normal controls, 5 patients with mucopolysaccharidosis and one patient with multiple sulfatase deficiency, was used to separate the sulfated hexosamines. The fractions eluted with 2M NaCl were analyzed according to the method of Reissig. Patients with Sanfilippo syndrome, type A, Sanfilippo syndrome, type D, Maroteaux-Lamy syndrome, Morquio syndrome, type A, and multiple sulfatase deficiency were clearly distinguished from normal controls. The procedure appeared most sensitive for Sanfilippo syndrome, type D, and multiple sulfatase deficiency, each of which involves deficient activity of N-acetylglucosamine 6-sulfate sulfatase.

Chromatography, Ion Exchange↗
PubMed1990

[Effect of 3-hydroxy-lup-20(29)en-23-28-dioic acid on rat experimental gastric ulcers].

3-hydroxy-lup-20(29) en-23-28-dioic acid (HLEDA) at doses of 50-100 mg/kg was found to be an effective anti-ulcer agent in three rat experimental gastric ulcer models: the indomethacin-induced, pyloric ligation-induced, and absolute alcohol-induced ulcers. Its anti-ulcer activities were similar to those of carbenoxolone. HLEDA was shown to increase the hexosamine levels in gastric juice collected from pylorus ligated stomachs. No influence on gastric secretion and peptic activity was observed. Carbenoxolone was found to significantly inhibit the elimination of Na+ and K+ in rat urine. HLEDA had no effect on the elimination of Na+ and K+.

Animals↗
PubMed1990

Biochemical changes in articular cartilage opposing full- and partial-thickness cartilage lesions in horses.

Using arthroscopic technique, identical diameter defects were created in the proximal articular surface of both intermediate carpal bones of 6 horses. One of each pair of defects was deepened to penetrate the subchondral plate. Removed cartilage was assayed for [35S] sulfate incorporation, total hexosamine content, and DNA content. Six weeks later, cartilage was harvested and similarly analyzed from the distolateral portion of the radius directly opposite the created lesions and the distomedial portion of the radius distant from the lesion. The repair tissue filling the full-thickness defect and the cartilage at the periphery of the partial-thickness lesion also were analyzed. There was a marked increase in synthetic activity (35S sulfate incorporation) opposite the full-thickness defect, compared with the cartilage opposite the partial-thickness defect. A marked decrease in glycosaminoglycan content in the cartilage opposite the full-thickness defect was found as compared with that opposite the partial-thickness defect. The repair tissue filling the full-thickness defect was highly cellular, high in synthetic activity, but low in glycosaminoglycan content. Insignificant changes occurred in the cartilage adjacent to the partial-thickness defect. On the basis of these results, we suggest that full-thickness defects at 6 weeks result in more detrimental change to the cartilage opposite it than do partial-thickness lesions of the same diameter.

Animals↗
PubMed1986

[Secretion of gastric mucus following maximal pentagastrin stimulation].

The aim of the thesis was the observation of the gastric mucus secretion on the basis of carbohydrate components and protein secretion into the gastric lumen. 15 healthy volunteers were investigated: 7 males and 8 females aged 20-37 (average rate 27). In this group gastric juice was aspirated after administration of single 6 micrograms/kg BW stimulus of pentagastrin. Concentration and output of hydrochloric acid, pepsin, protein and carbohydrate components of gastric juice fucose, sialic acid, hexosamines and hexoses were measured. Carbohydrate components and proteins included informations concerning gastric mucus secretion into gastric lumen. It was shown that the highest gastric mucus secretion occurred before maximal gastric acid secretion. This is of importance for keeping balance between so called aggressive and protective mechanisms. It is of great importance in pathophysiology of stomach.

Fucose↗
PubMed1989

[The effects of pyrrole aldehydephenyl semicarbazone on experimental gastric peptic ulcer models in rats].

Pyrrole aldehydephenyl semicarbazone was shown to be an effective anti-ulcer agent in five experimental models in rats, namely, the indomethacin-induced, acetic acid-induced, pyloric ligation-induced and 0.6 mol HCl, absolute alcohol-induced ulcers, at doses of 40-100 mg/kg. Its anti-ulcer activity and characteristics are similar to those of furazolidone. Its oral acute toxicity in mouse is much lower than furazolidone. This compound exhibited mild inhibitory effects on gastric pepsin secretion, caused increases in hexosamine level and decreases of DNA content in gastric juice. It showed no influence on gastric acid secretion and was considered to have "cytoprotective action" on the gastric mucosa. However, this compound was found to be ineffective against the stress-restraint gastric ulcer model.

Animals↗
PubMed1989

The hydroxyapatite-binding regions of a rat salivary glycoprotein.

The regions of a salivary sulphated glycoprotein which are involved in its attachment to hydroxyapatite (Biogel HTP) have been characterised. The sulphated glycoprotein, a 35S-labelled preparation from mixed palatal and buccal minor gland secretions of the rat was bound onto hydroxyapatite and the resultant glycoprotein-hydroxyapatite complex was sequentially digested with pronase E and alpha-L-fucosidase, a treatment which released 86.8% +/- 1.7% of the radioactivity of the initially bound glycoprotein. The fragments which remained attached to the hydroxyapatite after enzymic digestion were fractionated on Sephadex G-25 and analysed for carbohydrate and amino acid components. A range of amino acids were detected which could reflect both glycosylated and non-glycosylated-binding regions. Sialic acid, although considered to be involved in the attachment process was not detected in any of the fragments remaining after enzymic digestion, a finding which provides indirect evidence that the enzymically liberated products do not subsequently re-attach to the hydroxyapatite surface. The notable feature of the fractions with average Mr estimated at 1000 or less is the high proportion of N-acetylhexosamine and N-acetylgalactosamine. It is apparent that the hexosamine residues, which normally bear the ester sulphate moieties of sulphated glycoproteins, play an important role in the attachment of sulphated glycoproteins to hydroxyapatite.

Amino Acids↗
PubMed1989

[Quantitative and qualitative variations in the glycoproteins in the chick embryo brain].

Sugar content was examined in soluble and insoluble glycoproteins extracted from the chick embryo brain at different developmental stages. The content of hexosamines and uronic acids in the soluble fraction is higher during the whole period examined. The difference between the two fractions reaches a maximum at the 15th day. The insoluble fraction shows the highest content of sialic acid and fucose in comparison with the soluble one, especially toward hatching. The sialic acid/fucose ratio shows a different pattern in the two fractions examined, particularly in the soluble glycoproteins. The patterns of sialic acid and fucose indicate that quantitative and qualitative developmental changes occur in the soluble and insoluble glycoproteins. All sugars examined show significant changes on the 15th day, suggesting that this stage may represent a critical period in the development of the chick embryo brain.

Animals↗
PubMed1979

Carbohydrate utilization by the avian oviduct during the laying cycle.

In the present work the carbohydrate utilization by the avian oviduct during the egg formation was studied. The pattern obtained for total hexose, fucose, hexosamines, sialic acid, fructose and sulphate demonstrated that in the domestic fowl's oviduct the isthmus and the shell gland secrete the precursors for the protein carbohydrate substance of the mammillae and shell matrix and may contribute during the shell formation with the substrates necessary for the metabolic energy of the organ. The infundibulum only participates as a donor for the metabolic energy.

Animals↗
PubMed1985

Carbohydrate, protein and glycoprotein metabolism by the guinea-pig liver in chronic metribuzin poisoning.

Male guinea-pigs weighing 400-600 g, 8 months old, were given metribuzin directly into the gastric lumen over a period of 30 days (20 animals) or 90 days (20 animals) 6 times a week. In the liver of the poisoned animals, the glycogen level and the AspAT and AlAT activities, while in the serum the total protein and the fractions albumin, alpha 1-globulin and gamma-globulin significantly decreased; serum glucose and the serum fractions alpha 2-globulin and beta-globulin, each showed an increase. The glycogen level in the liver, total protein, glucose as well as the alpha 1 and alpha 2 globulin fractions in the serum showed not appreciable difference between 30 and 90 days of intoxication. After 90 days of metribuzin treatment AspAT and AlAT dropped in the liver and rose in the serum, in comparison to the 30-day values. As to the parameters of glycoprotein metabolism, the intoxicated animals showed a significant decrease and increase in concentration of hexosamines and sialic acids in the liver and serum, respectively. Metribuzin intoxication also cause a significant decrease in activity of glucosamine phosphate isomerase and significant increase in activity of glycosidases in the liver. The results suggest that metribuzin disturbs the metabolism of carbohydrates, proteins and glycoproteins in the guinea-pig liver.

Aldose-Ketose Isomerases↗
PubMed1987

Modulation of heparan sulfate biosynthesis. Effects of 6-diazo-5-oxo-L-norleucine and low glutamine on the synthesis of heparan sulfate proteoglycan by human colon carcinoma cells.

We have investigated the biosynthesis of heparan sulfate proteoglycan in human colon carcinoma cells cultured in either the absence of L-glutamine or the presence of 6-diazo-5-oxo-L-norleucine (DON), a glutamine analogue. Following a 24-h incubation with 100 micrograms/ml DON (0.58 mM) or without L-glutamine, the incorporation of [35S]sulfate was maximally inhibited to about 50%, whereas the incorporation of [3H]leucine or [3H]serine and their specific activity were not significantly affected. Several lines of evidence indicate that the inhibition of [35S]sulfate incorporation was mediated by a reduction in the intracellular pool of UDP-N-acetylhexosamine: the intracellular hexosamine levels were reduced by about 50%; taking into account the changes in specific activity, the incorporation of [3H]glucosamine was also significantly inhibited; and exogenous D-glucosamine (2.3 mM) was capable of substantially reversing the inhibitory effects of DON. This decrease in endogenous sugar supply resulted in the generation of an underglycosylated, lower buoyant density proteoglycan which contained significantly fewer heparan sulfate chains of otherwise normal size and sulfation and even fewer O-linked oligosaccharides. These biochemical changes were corroborated ultrastructurally by the appearance of smaller ruthenium red-stained proteoglycans on the surface of the cells. DON also caused a marked inhibition of cell proliferation and profound morphological changes, both of which were reversible upon culturing in DON-free medium. These results demonstrate that perturbations in glutamine metabolism have profound effects on the structure of heparan sulfate proteoglycan and on the phenotype of human colon carcinoma cells and indicate that DON treatment could be useful for studying post-translational modifications of proteoglycans in various cell systems.

Azo Compounds↗
PubMed1988

Biochemical heterogeneity within the maturing rabbit medial collateral ligament.

The purpose in this investigation was to determine the biochemical composition of the normal rabbit medial collateral ligament (MCL) along its length during growth and maturation. Water content and hexosamine concentration as an index of glycosaminoglycan content and collagen concentration were quantified and results compared statistically for anatomically identified MCL segments at various ages. These data demonstrate differences in all parameters at different locations along the ligament and at different ages. Biochemical differences were noted between midsubstance and periinsertional areas. There were subtle differences between the two insertion sites of this ligament at all ages. These results indicate that the rabbit MCL is not homogeneous biochemically along its length and that its matrix composition changes with growth and maturation.

Aging↗
PubMed1988

Type II achondrogenesis-hypochondrogenesis: identification of abnormal type II collagen.

We have extended the study of a mild case of type II achondrogenesis-hypochondrogenesis to include biochemical analyses of cartilage, bone, and the collagens produced by dermal fibroblasts. Type I collagen extracted from bone and types I and III collagen produced by dermal fibroblasts were normal, as was the hexosamine ratio of cartilage proteoglycans. Hyaline cartilage, however, contained approximately equal amounts of types I and II collagen and decreased amounts of type XI collagen. Unlike the normal SDS-PAGE mobility. Two-dimensional SDS-PAGE revealed extensive overmodification of all type II cyanogen bromide peptides in a pattern consistent with heterozygosity for an abnormal pro alpha 1(II) chain which impaired the assembly and/or folding of type II collagen. This interpretation implies that dominant mutations of the COL2A1 gene may cause type II achondrogenesis-hypochondrogenesis. More generally, emerging data implicating defects of type II collagen in the type II achondrogenesis-hypochondrogenesis-spondyloepiphyseal dysplasia congenita spectrum and in the Kniest-Stickler syndrome spectrum suggest that diverse mutations of this gene may be associated with widely differing phenotypic outcome.

Amino Acids↗
PubMedDate not supplied

[In vivo effect of L-thyroxine on carbohydrate content of glycoproteins in subcellular fractions of the rat liver].

Effect of various doses of L-thyroxin on content of some carbohydrates (sialic acids, hexosamines, hexoses bound with proteins and L-fucose) in glycoproteins was studied in rat liver subcellular fractions. Content of these carbohydrates was altered similarly in liver tissue, whereas various doses of the hormone caused different changes of the glycoprotein components in liver tissue subcellular fractions. Within 24 days after L-thyroxin administration small doses of the hormone led to elevation of these carbohydrates in mitochondria and microsomes, while their content was unaltered in biomembranes, intermediate doses caused a decrease of the carbohydrates in mitochondria and microsomes and an increase in plasmatic mitochondrial and microsomal membranes, high doses of L-thyroxin caused a decrease of the carbohydrates in all the structures studied. Duration of normalization of the glycoprotein carbohydrate components in rat liver tissue depended on the L-thyroxin dose administered.

Animals↗
PubMed1988

Regional differences in matrix formation in the healing flexor tendon.

In 20 white leghorn chickens, the effect of proximity (proximal vs. distal) to the repair site and the effect of sheath excision versus sheath repair on biochemical matrix formation in the healing zone 2 flexor tendon were studied. In 14 animals, the profundus tendon of the long toe on both feet was lacerated and repaired in zone 2. In the right foot, the sheath was repaired, and on the left foot, the sheath was excised. Segments proximal and distal to the laceration site were studied at six weeks postrepair compared to control segments. Sheath excision versus sheath repair had no effect on the net matrix formation of the healing flexor tendon. A higher DNA content and lower hydroxyproline and hexosamine contents were present in the healing tendons, indicating the healing process was not complete at six weeks. Sheath excision versus sheath repair had no effect on net matrix formation in the healing tendon. There is no difference in DNA content or glycosaminoglycan content in the proximal versus distal segments. There was a significantly greater net hydroxyproline content in the proximal segment versus the distal segment of the healing tendon, which was not present in similar control segments. These results support the concept that the zone 2 flexor tendon does not respond to injury as a homogeneous structure.

Animals↗
PubMed1987

[Carbohydrate metabolic disorder in experimental secretory diarrhea induced by cholera toxin].

Cholera toxin induced a massive mucus accumulation and a significant enhancement of arteriovenous difference in glucose concentration in the isolated loop of rabbit small intestine. Mucus hexosamine secretion increased threefold, whereas mucous lactate level remained unchanged. It is suggested that intensive mucus secretion is ensured by significant amounts of blood glucose, whose level is 65% increased, possibly due to the observed 1-6-fold liver gluconeogenesis acceleration. Though the mechanism of the latter is not yet known, the data obtained provide evidence that this stimulation is not cAMP-dependent.

Animals↗
PubMedDate not supplied

[Skin changes in advanced age--biochemical findings corresponding to morphology?].

The clinically relevant morphological changes of the skin during aging can be summarized by the term "senile atrophy". The changes are a diminished thickness of epidermis with a reduced mitosis rate of epidermal basal cells, shortened and attenuated rete ridges, reduction of epidermal appendages, and a decreased number of fibroblasts and capillaries in the dermis. Corresponding to these morphological findings regarding the cell number in the senile skin (cutis) we found a slight decrease in the DNA concentration of human and rat cutis. The specific DNA activity (3H-thymidine incorporation rate related to DNA concentration) decreased in presenile versus adult animals. The mesenchymal changes in the dermis have been morphologically described by the term "senile elastosis" or "elastoid collagen degeneration", but in fact they correspond to a progressive collagen denaturation with aging. The total collagen concentration, here determined as the hydroxyproline concentration in the human cutis, shows almost constant values from the 3rd until the 9th decade of life in both sexes. This is also true for the skin of two different rat strains. The insoluble collagen fraction shows a relative increase to the disadvantage of the soluble collagen fractions, which can be interpreted as an indicator of a decelerated collagen turnover. In spite of the decelerated turnover, i.e. a prolonged half-life of the collagen metabolism in the skin, the indicators of the collagen neosynthesis (14C-proline incorporation rate, specific hydroxyproline activity, prolyl-hydroxylase activity) are significantly elevated in the cutis of presenile versus adult rats. Any connection of these findings with a possible change in the distribution of collagen types in the senile skin (e.g. pericapillar fibrosis with increase of collagen type I as well as changes in the distribution of type I, III, IV and V) can only be discussed at present. The glycosaminoglycans in the cutis show a minimal increase of the total content of hexosamines and uronic acids with a significant shift in the ratio of the glycosaminoglycan components in favour of dermatan sulfate and keratan sulfate and to the disadvantage of hyaluronic acid and partly also of chondroitin-4-sulfate and -6-sulfate. The neosynthesis of sulfated glycosaminoglycans (indicator method: 35S-sulfate incorporation rate) is only slightly increased whereas the enzyme activities being specific for the glycosaminoglycan catabolism (beta-glucuronidase, beta-N-acetyl-glucosaminidase) are significantly decreased with aging of the skin.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetylglucosaminidase↗
PubMedDate not supplied

Effect of estrogen and testosterone on the gastric secretion of rats and conscious rabbits.

Shay rats and conscious rabbits were used to study the effect of sex hormones on gastric secretion. Daily injections of estradiol-di propionate and testosterone-propionate were given separately to each set of animals, while the control animals received solvent alone for the same duration of time. Estrogen inhibited gastric acid output but augmented the mucus secretion as evidenced by increased hexosamine and fucose contents; and testosterone had the reverse effects. The effect of estrogen was more potent that of testosterone. An inverse relationship between gastric acid and mucus secretion has been noted. Peptic activity varied independently of the acid output. These hormones seemed to vary the acid output by modifying the composition of mucus secretion.

Animals↗
PubMed1985

Proteoglycans of human infant intervertebral disc. Electron microscopic and biochemical studies.

The ground substance of the intervertebral disc consists primarily of proteoglycans, which give the tissue its stiffness to compression and its resiliency. To investigate the structure and composition of these molecules, we extracted them from human infant nucleus pulposus under associative conditions and from human infant annulus fibrosus and cartilage end-plate under dissociative conditions. We examined the degree of aggregation, the composition, the electron microscopic appearance, and the dimensions of the proteoglycans of the intervertebral disc and compared their structure and dimensions with those of the proteoglycans from bovine hyaline cartilage. Aggregates represented 52 per cent of the proteoglycans of the nucleus pulposus between the ages of one and ten days but only 28 per cent between the ages of six and eight months. Preparations from the corresponding annuli contained 59 per cent aggregates at one to ten days and 47 per cent at six months. The corresponding cartilage end-plate preparations contained 45 and 40 per cent aggregates. The proteoglycans of the annulus fibrosus and cartilage end-plate contained more protein and less hexosamine than did those of the nucleus pulposus. Electron microscopy showed that approximately two-thirds of the aggregates from nucleus pulposus consisted of very short hyaluronate filaments with closely packed monomers. The other third had longer hyaluronate filaments and wider distances between monomers, and closely resembled the aggregates from the annulus fibrosus and cartilage end-plate. Aggregated monomers consisted of two segments: a thin segment connecting directly to the hyaluronic acid filament and a thick segment extending peripherally from the thin segment. The thin segment formed about 12 per cent of the total monomer length in the samples from all three disc tissues. The lower proportion of aggregated monomers, the lower protein content, and the smaller aggregates with closely packed monomers suggest that the nucleus pulposus may contain less link protein than do the annulus fibrosus and cartilage end-plate. Compared with proteoglycan aggregates from bovine hyaline cartilage, proteoglycan aggregates from human intervertebral disc were shorter and had fewer monomers and wider spacing between monomers. The aggregated monomers from the three components of the intervertebral disc had an average length of 209 +/- 90 nanometers, compared with 210 +/- 114 nanometers for monomers from hyaline cartilage of skeletally mature cows, 250 +/- 116 nanometers for monomers from hyaline cartilage of skeletally immature calves, and 288 +/- 108 nanometers for monomers from fetal animals.(ABSTRACT TRUNCATED AT 400 WORDS)

Cartilage↗