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Biomedical subjects

S Yu

Publications and source records attributed to S Yu.

At least 325 records · Page 18Linked to original sources
PubMed1996

[Community trial for safety and immunogenicity of oral-administered lyophilized rBS-WC cholera vaccine].

In order to evaluate the safety and immunogenicity of domestic produced lyophilized recombinant, B-subunit, inactivated whole cell vaccine of vibrio cholerae (rBS-WC), 369 subjects were randomly divided into three groups and observed with masking method, one with high dose of vaccine (5 mg rBS and 10" WC), another with low dose (1 mg rBS and 10" WC), and the control one with placebo. Three doses of vaccine were given orally at an interval of seven days and 14 days, respectively. Results showed that only one subject had mild adverse reaction in the vaccine group (1/247) and none in the control group. Serum and fecal antibody conversion rates and average levels of antibodies in the two vaccine groups were significantly higher than those in control one. There was no significant difference in serum and fecal antibody conversion rate and average antibody levels between the two vaccine groups. But, antibody response was different among subjects of various sex, age, and vaccine doses. It indicates that rBS-WC vaccine of vibrio cholerae had good immunogenicity and safety.

Administration, Oral↗
PubMed1996

[Effects of interleukin-1 on the differentiation of osteoblasts].

By use of quantitative histochemistry, effects of interleukin 1 (IL1) on the differentiation of osteoblasts derived from neonatal rabbit calvaria were studied. The results showed that IL 1 inhibits the alkaline phosphatase activity in the cultured osteoblasts. Also, both quantitative immunohistochemistry study and radioimmunoassay study showed that IL-1 has the ability to stimulate osteocalcin production and secretion in the cultured osteoblasts. Our results suggest that IL 1 plays a role in the regulation of osteoblastic differentiation, and in the end inhibits the calcification of bone matrix.

Alkaline Phosphatase↗
PubMed1996

[Analysis of serum osteocalcin of patients with periodontitis].

To evaluate the effect of bone formation on alveolar bone destruction in periodontitis, we selected 20 patients with severe chronic periodontitis (CP), and 9 patients with rapidly progressive periodontitis (RPP). Their serum osteocalcin was determined by radioimmunoassay (RIA). The serum osteocalcin in 65.0% patients with CP and 66.7% patients with RPP was lower than that in normal persons. It is suggested that osteoblastic activity and bone formation ability of periodontitis patients are lower than those of normal persons. The alveolar bone destruction in periodontitis results from not only increased osteoclastic activity and bone resorption but also decreased osteoblastic activity and bone formation.

Adult↗
PubMed1995

Association of a chromosome deletion syndrome with a fragile site within the proto-oncogene CBL2.

The fragile site FRA11B has been localized to the p(CCG)n repeat of the CBL2 proto-oncogene. A proportion of Jacobsen (11q-) syndrome patients inherited a chromosome carrying a CBL2 p(CCG)n expansion, which was truncated close to FRA11B. These results have broad implications for the role of p(CCG)n repeat expansion in the aetiology of genetic disease involving chromosome rearrangements.

Base Sequence↗
PubMed1995

alpha-1,4-Glucan lyase, a new class of starch/glycogen degrading enzyme. III. Substrate specificity, mode of action, and cleavage mechanism.

The alpha-1,4-glucan lyase (EC 4.2.2.-), purified from the red alga Gracilariopsis lemaneiformis, is a single polypeptide with a molecular mass of 116,654 Da as determined by matrix-assisted laser-desorption mass spectrometry. It degraded maltose, maltosaccharides, amylose, amylopectin and glycogen, forming 1,5-anhydro-D-fructose from the non-reducing end groups. The substrate specificity, mode of action, and cleavage mechanism of the enzyme were studied by using various naturally occurring and synthesized substrates. This enzyme was highly specific for the alpha-1,4-D-glucosidic bond. When a linear alpha-1,4-glucan was used as substrate, the enzyme split the substrate from the non-reducing end and released 1,5-anhydro-D-fructose successively until only one glucose unit was left. When a branched pentasaccharide of 6(2)-alpha-maltosylmaltotriose, obtained from glycogen by alpha-amylase limitation, was used as substrate, the glucose group in the 4-position of the 4,6-branched residue was not cleaved off. Using maltoheptaose as substrate and following the reaction with HPLC and 1H-NMR spectroscopy, it was found that the action mode of the lyase followed a multichain attack mechanism. 1H- and 13C-NMR spectroscopic studies on unlabelled and labelled amylose (1-2H, 2-2H, 1-13C) as substrates indicated that the lyase cleaved the C-(1')-O(4) bond forming a double bond between C-1' and C-2', thus forming the enol form of 1,5-anhydro-D-fructose. It also indicated that the catalytic process of the lyase involved proton exchanges among C-1, C-2, C-3 and the solvent.

Carbohydrate Sequence↗
PubMed1995

Second-generation leukotriene B4 receptor antagonists related to SC-41930: heterocyclic replacement of the methyl ketone pharmacophore.

Our previous reports have highlighted the first-generation leukotriene B4 (LTB4) receptor antagonist SC-41930 (7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)propoxy]3,4- dihydro-8-propyl-2H-1-benzopyran-2-carboxylic acid) which has potent oral, topical, and intracolonic activity in various animal models of inflammation. Extensive structure-activity relationship studies, in which a series of heterocyclic replacements for the methyl ketone functional group of SC-41930 was explored, identified SC-50605 (7-[3-[2-(cyclopropylmethyl)-3-methoxy-4- (4-thiazolyl)phenoxy]propoxy]-3,4-dihydro-8-propyl-2H-1-benzopyran-2- carboxylic acid) as an optimized analog within a series of thiazoles. SC-50605 was found to be significantly more potent than SC-41930 in LTB4 receptor binding, chemotaxis, and degranulation assays. It also displayed very good activity in animal models of colitis and epidermal inflammation by oral, topical, intravenous, and intracolonic routes of administration. The resolved enantiomers of SC-50605 were obtained by chiral chromatography and both demonstrated good in vitro and in vivo activity. The (+)-isomer (SC-52798) is currently being evaluated as a potential clinical candidate for psoriasis and ulcerative colitis therapy.

Amino Acid Sequence↗
PubMed1995

Immunohistochemical localization of glucose transporters (GLUT1 and GLUT3) in the rat hypothalamus.

Immunohistochemical localization of the glucose transporters was studied in the rat hypothalamus by using a specific rabbit antiserum raised against either the isoform 1 (GLUT1) or the isoform 3 (GLUT3). Immunoreactive staining for GLUT1 was found in glia cells and capillaries, whereas positive staining for GLUT3 occurred mainly in neurons and partly in ependymal cells. Double immunostaining indicated that a small population of GLUT1-positive cells were reactive for glial fibrillary acidic protein, a marker for astrocytes. Another doubly stained section showed that GLUT1-positive glia cells were never stained with an OX42 antibody, a marker for microglia cells. Neurons staining positively for GLUT3, often large in cell size, were confined mainly in the lateral hypothalamic area and partly in the dorsomedial and periventricular hypothalamic nuclei. Possible significance of these two glucose transporters in the hypothalamus is briefly discussed.

Amino Acid Sequence↗
PubMed1995

Xylulose fermentation by Saccharomyces cerevisiae and xylose-fermenting yeast strains.

Xylulose fermentation by four strains of Saccharomyces cerevisiae and two strains of xylose-fermenting yeasts, Pichia stipitis CBS 6054 and Candida shehatae NJ 23, was compared using a mineral medium at a cell concentration of 10 g (dry weight)/l. When xylulose was the sole carbon source and fermentation was anaerobic, S. cerevisiae ATCC 24860 and CBS 8066 showed a substrate consumption rate of 0.035 g g cells-1 h-1 compared with 0.833 gg cells-1 h-1 for glucose. Bakers' yeast and S. cerevisiae isolate 3 consumed xylulose at a much lower rate although they fermented glucose as rapidly as the ATCC and the CBS strains. While P. stipitis CBS 6054 consumed both xylulose and glucose very slowly under anaerobic conditions, C. shehatae NJ 23 fermented xylulose at a rate of 0.345 gg cells-1 h-1, compared with 0.575 gg cells-1 h-1 for glucose. For all six strains, the addition of glucose to the xylulose medium did not enhance the consumption of xylulose, but increased the cell biomass concentrations. When fermentation was performed under oxygen-limited conditions, less xylulose was consumed by S. cerevisiae ATCC 24860 and C. shehatae NJ 23, and 50%- 65% of the assimilated carbon could not be accounted for in the products determined.

Anaerobiosis↗
PubMed1995

Antiinflammatory effects of second-generation leukotriene B4 receptor antagonist, SC-53228: impact upon leukotriene B4- and 12(R)-HETE-mediated events.

Leukotriene B4 (LTB4) and 12(R)-hydroxyeicosatetraenoic acid [12(R)-HETE] are proinflammatory products of arachidonic acid metabolism that have been implicated as mediators in a number of inflammatory diseases. When injected intradermally into the guinea pig. LTB4 and 12(R)-HETE elicit a dose-dependent migration (chemotaxis) of neutrophils (PMNs) into the injection sites as assessed by the presence of a neutrophil marker enzyme myeloperoxidase. SC-41930 (7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)propoxyl]-3,4-dihy dro-8-propyl-2H - 1-benzopyran-2-carboxylic acid), a first-generation LTB4 receptor antagonist, inhibited the chemotactic actions of LTB4 when given orally with an ED50 value of 1.7 mg/kg. The second-generation LTB4 receptor antagonist, SC-53228 [(+)-(S)-7-(3-(2-(cyclopropylmethyl)-3-methoxy-4- [(methylamino)carbonyl]phenoxy)propoxy)-3,4-dihydro-8-propyl-2H-1- benzopyran-2-propanoic acid], inhibited LTB4-induced chemotaxis when given intragastrically with an ED50 value of 0.07 mg/kg. Furthermore, SC-53228 inhibited 12(R)-HETE-induced granulocyte chemotaxis with an oral ED50 value of 5.8 mg/kg. When dosed orally over a range of 0.03-100 mg/kg, SC-53228 gave Cmax plasma concentrations of 0.015-41.1 micrograms/ml. SC-53228 inhibited LTB4-primed membrane depolarization of human neutrophils with an IC50 value of 34 nM. As a potent LTB4 receptor antagonist, SC-53228 may well have application in the medical management of disease states such as asthma, rheumatoid arthritis, inflammatory bowel disease, contact dermatitis, and psoriasis, in which LTB4 and/or 12(R)-HETE are implicated as inflammatory mediators.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1995

Copper metabolism in analbuminaemic rats fed a high-copper diet.

Copper metabolism in male Nagase analbuminaemic (NA) rats was compared with that in male Sprague Dawley (SD) rats fed purified diets containing either 5 or 100 mg Cu/kg diet. Dietary copper loading increased hepatic and kidney copper concentrations in both strains to the same extent, but baseline values were higher in the NA rats. There was no strain difference in true and apparent copper absorption nor in faecal endogenous and urinary copper excretion. NA rats had higher levels of radioactivity in kidneys at 2 hr after intraperitoneal administration of 64Cu. As based on the distribution of added 64Cu, about 70% of plasma copper appeared to be in the non-protein compartment in the NA rats, whereas in SD rats, it was only about 1%. It is concluded that the NA rats are able to maintain a relatively normal metabolism of copper, even after dietary copper challenge. In the NA rats, zinc concentrations in kidneys, liver and urinary zinc excretion were elevated when compared with SD rats. The high-copper diet did not affect tissue zinc concentrations and apparent zinc absorption in both strains of rats.

Administration, Oral↗
PubMed1995

Iron and copper metabolism in analbuminaemic rats fed a high-iron diet.

The metabolism of iron and copper in male Nagase analbuminaemic (NA) and Sprague Dawley (SD) rats was compared. Relative liver weight was higher and spleen weight significantly lower in NA than SD rats. In NA rats, red blood cell count, haemoglobin and haematocrit were lower, whereas plasma transferrin, total iron-binding capacity and mean corpuscular haemoglobin were higher when compared with SD rats. Iron concentrations in plasma, liver, kidneys and heart were higher, and those in the spleen and tibia were lower, in NA rats. The iron concentrations in liver and spleen were positively correlated with the amount of brown pigment as observed histopathologically. Bile flow as well as biliary iron and copper excretion were higher in NA than SD rats. Copper concentrations in liver, kidneys and plasma were higher in NA rats. Plasma levels of ceruloplasmin were about two-fold higher in NA rats. The feeding of a high-iron diet reduced kidney copper concentrations in both strains of rats, which was associated with a decrease in the absorption and biliary excretion of copper.

Animals↗
PubMed1995

High tin intake reduces copper status in rats through inhibition of copper absorption.

The mechanism underlying the reduced Cu status in rats fed on a high-Sn diet was investigated. Male rats aged 4 weeks were fed ad lib. on purified diets containing either 1 or 100 mg Sn/kg and demineralized water for a period of 4 weeks. The high-Sn diet had no effect on feed intake, body-weight gain or weight of liver and kidney but significantly reduced Cu concentrations in plasma, liver and kidney. Biliary Cu excretion was decreased significantly in rats fed on the high-Sn diet. Apparent Cu absorption (Cu intake-faecal Cu) was not affected by the high-Sn diet, but the estimate of true Cu absorption (Cu intake-(faecal Cu-biliary Cu)) was significantly reduced. We conclude that high Sn intake reduces Cu status in rats through inhibition of Cu absorption. The decreased biliary Cu excretion observed on the high-Sn diet is a result of the reduced Cu absorption.

Animals↗
PubMed1995

High iron intake depresses hepatic copper content in goats.

Earlier studies with ruminants point to a depressant effect of dietary iron on the copper status. To verify this we determined hepatic copper concentrations in dry, non-pregnant goats subjected to a 56 x 56-days cross-over trial with adequate copper rations containing either 269 or 2380 mg iron/kg dry matter. High iron intake reduced the group mean plasma copper (by 18%) and caeruloplasmin activity (by 13%) and produced a significant decrease (27%) in hepatic copper concentrations. Hepatic iron concentrations were raised (by 56%) after feeding the high iron ration. It is concluded that high dietary levels of iron, within the range of their fluctuation in silage and forage, can impair the copper status of ruminants, especially when concurrent intakes of copper are low.

Animals↗
PubMed1995

Plasma cholesterol-predictive equations demonstrate that stearic acid is neutral and monounsaturated fatty acids are hypocholesterolemic.

In the present study we used regression analyses to evaluate the effects of stearic acid (18:0) on total cholesterol (TC), low-density-lipoprotein-cholesterol (LDL-C), and high-density-lipoprotein-cholesterol (HDL-C) concentrations (mmol/L). Using data from 18 articles, we developed the following predictive equations (monounsaturated fatty acids, MUFAs; polyunsaturated fatty acids, PUFAs): delta TC = 0.0522 delta 12:0-16:0 - 0.0008 delta 18:0 - 0.0124 delta MUFA - 0.0248 delta PUFA; delta LDL-C = 0.0378 delta 12:0-16:0 + 0.0018 delta 18:0 - 0.0178 delta MUFA - 0.0248 delta PUFA; delta HDL-C = 0.0160 delta 12:0-16:0 - 0.0016 delta 18:0 + 0.0101 delta MUFA + 0.0062 delta PUFA. Our analyses revealed that unlike the other long-chain saturated fatty acids (SFAs), stearic acid had no effect on TC and lipoprotein cholesterol concentrations in men and women. MUFAs elicited an independent hypocholesterolemic effect that we believe is due to the small amount of 12:0-16:0 in the experimental diets evaluated. The observation that stearic acid has unique effects on TC, LDL-C, and HDL-C provides additional compelling evidence that it be distinguished from the other major SFAs in blood cholesterol predictive equations.

Adult↗
PubMed1995

Structure of the mouse basigin gene, a unique member of the immunoglobulin superfamily.

Basigin is a membrane glycoprotein belonging to the immunoglobulin superfamily. The mouse basigin gene was isolated from a genomic DNA library of the BALB/c mouse, and the structure of the gene and its flanking region (11.8 kb) was completely determined. The mouse basigin gene consists of seven exons and six introns spanning 7.5 kb. The distance between the first and second exons is 5.1 kb. The first immunoglobulin-like domain of the basigin molecule is encoded by the second and third exons, and the second immunoglobulin-like domain by the fourth and fifth exons. The fifth exon encodes not only the C proximal portion of the second immunoglobulin-like domain, but also the transmembrane domain and a small portion of the cytoplasmic domain. Thus, the organization of the basigin gene is unique. The 5' upstream sequence of the basigin gene contains no TATA box or CAAT box, but has a CpG-rich island. The BALB/c genomic sequence of all seven exons is consistent with the cDNA sequences of the 129/SV and Swiss mice except several minor substitutions in the 3'-terminal sequence of the 3'-noncoding region. No protein polymorphism has so far been found in basigin of different mouse strains.

Amino Acid Sequence↗