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Biomedical subjects

N Hosoya

Publications and source records attributed to N Hosoya.

At least 73 records · Page 4Linked to original sources
PubMed1984

Nondigestibility of a new sweetener, "Neosugar," in the rat.

The digestion of Neosugar, a mixture of 1F-(1-beta-fructofuranosyl)n-1 sucrose [n = 2, 1-kestose (GF2); n = 3, nystose (GF3); n = 4, 1F-beta-fructofuranosyl nystose (GF4)] was investigated in vitro and in vivo by using the rat. The results obtained were as follows. GF2 and GF3 were not hydrolyzed by a pancreatic homogenate. The GF2- and GF3-hydrolyzing activities of the enzymes in the intestinal mucosa homogenate were negligible compared with the activities of maltase and sucrase. GF2 and GF3 added to the incubation mixture did not affect the activities of sucrase and maltase in the intestinal mucosa. Long-term ingestion of Neosugar did not cause induction or suppression of GF2- and GF3-hydrolyzing enzymes in the small intestine. [U-14C]Neosugar injected intravenously was rapidly excreted in the urine without having undergone any degradation. These results indicate that Neosugar, which consists of GF2, GF3 and GF4, is scarcely hydrolyzed by the digestive enzymes of the gastrointestinal tract and internal organs, and that suggests to us that Neosugar is not utilized as an energy source in the body.

Animals↗
PubMed1984

Hypertrophic effect of unavailable carbohydrate on cecum and colon in rats.

The effects of unavailable carbohydrate on the cecum and colon were investigated in rats raised on diets containing 20% of glucomannan or cellulose for 8 weeks. Glucomannan ingestion caused the increase of cecum and colon weights, and the effect was greater in the cecum than in the colon. However, on ingestion of cellulose, a remarkable increase in tissue weight was observed in the colon rather than in the cecum. Measurement of DNA, RNA and protein in cecal and colonic mucosa demonstrated that the cecal enlargement caused by glucomannan was dependent on the increases in both number and size of mucosal cells, and that the cecal and colonic enlargements caused by cellulose and the colonic enlargement caused by glucomannan resulted from an increase in the number of mucosal cells; i.e., hyperplasia. (Na + K)ATPase activity of the cecal and colonic mucosa in the cellulose and glucomannan groups was significantly higher than that in the control group. Thus, (Na + K)ATPase activity was increased proportionally to the intensity of the process of tissue enlargement.

Animals↗
PubMed1984

Mode of rat cecal enlargement induced by a short-term feeding on glucomannan.

The increase in wet weight of rat cecum was evident at 16 hr of glucomannan ingestion and continued until 184 hr (the longest period observed in this experiment), reaching about 2.5-fold. The ratios of total protein/DNA and RNA/DNA were both always higher in cecum of rats fed glucomannan than the control group (0 hr). During the initial 40 hr, no significant change in total DNA content was observed with the increase in total protein and RNA. Furthermore, the incorporation rate of [3H]thymidine in cecal DNA was even lower in the glucomannan feeding than the control (0 hr) during the initial 40 hr. After 88 hr of the experiment, however, a significant increase in the synthetic rate of DNA was found as well as [14C]leucine incorporation into total protein. It was discussed that a hypertrophic change in rat cecum was initially induced by glucomannan ingestion and was followed by hyperplastic growth under continuous exposure of glucomannan.

Animals↗
PubMed1983

Effect of aging and castration on the changes in the levels of bone gamma-carboxyglutamic acid-containing protein in bone and serum of female rat.

Using female rats from 2 to 64 weeks old, the changes in bone gamma-carboxyglutamic acid-containing protein (BGP) levels in bone and serum were studied in relation to the changes in calcium metabolism during aging. Intestinal calcium transport, serum phosphorus level, bone origin serum alkaline phosphatase activity and serum BGP content were high in rapidly growing animals and then decreased with aging. Serum BGP content correlated well to bone origin serum alkaline phosphatase activity. Bone density, bone ash content and bone BGP content increased during aging. Bone BGP content was correlated to bone density which indicates the level of bone calcification. Moreover, the effect of castration on calcium metabolism and bone and serum BGP contents were observed in young (10 weeks old) and aged (40 weeks old) female rat at 12 and 24 weeks after operation. Intestinal calcium transport in ovariectomized rat was significantly lower than in sham operated rat. Serum phosphorus level and serum BGP content were increased in castrated female rat. However, serum calcium level and bone origin serum alkaline phosphatase activity did not show a significant change in castrated female rat. Bone density was significantly decreased in aged rat at 24 weeks after operation. During aging or castration, serum BGP content changed more than bone BGP content. The determination of change in serum BGP levels in various disorders of calcium metabolism would be very informative in future study.

1-Carboxyglutamic Acid↗
PubMed1983

Biliary immunoglobulins in protein-energy malnourished rats.

The effect of protein-energy malnutrition on biliary immunoglobulins was investigated in rats fed isocaloric diets containing 0.5%, 5%, and 18% casein, respectively. Growth was severely retarded in rats fed 0.5% casein diet and moderately in rats fed 5% casein diet, and these groups had decreases in serum albumin and total protein levels. Since the energy intake was low in rats fed protein-insufficient diets, the nutritional status was defined not as protein malnutrition but protein-energy malnutrition. Depression of systemic immune functions in protein-energy malnourished rats were demonstrated by serum IgG and IgA levels, and antibody responses to dinitrophenylated bovine gamma globulin, a T-cell dependent antigen. The depressed systemic immune functions observed in those rats were suggested to be caused by thymic atrophy. IgA levels in bile were much higher in all groups than IgG levels. IgG levels decreased in rats fed 0.5% casein diet but not in rats fed 5% casein diet, while IgA levels decreased in rats fed 5% and 0.5% casein diet relating to casein levels. The ratios of IgA to IgG in bile also decreased in rats fed protein-insufficient diets. By sucrose density gradient centrifugation secretory IgA levels in bile were shown to decrease in rats fed 0.5% casein diet, suggesting that the secretion of IgA by hepatic parenchymal cells is depressed in the protein-energy malnourished rats.

Animals↗
PubMed1983

Effect of pyridoxal 5'-phosphate on the 1,25-dihydroxyvitamin D3 receptor system.

The effect of pyridoxal 5'-phosphate on the 1,25-dihydroxyvitamin D3 receptor system has been studied by using pig intestinal chromatin. Pyridoxal 5'-phosphate did not affect the binding of 1,25-dihydroxyvitamin D3 to its receptor extracted from chromatin with hypertonic KCl, although in the presence of pyridoxal 5'-phosphate 1,25-dihydroxyvitamin D3-receptor complexes were not readily precipitated with polyethylene glycol. In contrast, pyridoxal 5'-phosphate showed a potency to dissociate the 1,25-dihydroxyvitamin D3 receptor from chromatin in a dose-dependent manner. A low concentration of pyridoxal 5'-phosphate was as effective as hypertonic KCl in dissociating the receptor from chromatin, while pyridoxine, p-nitrophenyl phosphate, or inorganic phosphate was much less effective. These observations suggest the inhibitory effect of pyridoxal 5'-phosphate on the recognition of 1,25-dihydroxyvitamin D3 by its receptor system.

Animals↗
PubMed1983

Intestinal absorption of dinitrophenyl-lysine and effect of immunization with dinitrophenylated bovine serum albumin.

The intestinal absorption of dinitrophenyl-lysine (DNP-lys) was studied with a special interest on the role of the immune system in the absorption of small molecules which are recognized as nonself. [3H]-DNP-lys was rapidly absorbed by ligated intestinal loops in situ via a saturable and unique route. When [3H]-DNP-lys was preincubated with the immune serum obtained from rats immunized with dinitrophenylated bovine serum albumin (DNP-BSA), the [3H]-DNP-lys absorption was depressed. The absorption of [3H]-DNP-lys in DNP-BSA-immunized rats was depressed compared to the control. The results obtained suggest that the immune system play a role in avoiding the absorption of small molecules with antigenicity.

Animals↗
PubMed1983

Changes of the activity and content of sucrase-isomaltase complex in the intestinal mucosa during the development of streptozotocin-induced diabetes in rats.

The changes in the activity and content of sucrase-isomaltase complex (S-I) in the intestinal mucosa were studied during the development of diabetes induced by streptozotocin in rats. On days 0, 1, 3, 5, and 10 after an intraperitoneal injection of streptozotocin (70 mg/kg), the enzyme activity and the enzyme content were observed in the jejunum and ileum. Sucrase and isomaltase activities markedly increased from the 3rd day both in the jejunum and ileum, and kept increasing till the 10th day especially in the ileum. The enzyme content of S-I also increased in parallel with its activity during the development of diabetes. However, in the early stage of diabetes, sucrase activity per microgram of S-I content increased both in the jejunum and ileum. Isomaltase activity per microgram of S-I content increased temporarily in the ileum. These results suggest that the increase of disaccharidase activities in the early stage of diabetes induced by streptozotocin is not only due to the increase of the enzyme content, but also due to the change of the enzyme catalytic property.

Animals↗
PubMed1983

The changes of bone gamma-carboxyglutamic acid-containing protein in bone and serum of developing chick.

The changes of bone gamma-carboxyglutamic acid-containing protein (BGP) levels in bone and serum were studied in relation to those in calcium metabolism using chick embryos and chicks aged from 13 days' incubation to 8 weeks old. Chick BGP was determined by radioimmunoassay using antiserum to purified chick BGP. BGP levels in bone and serum increased significantly at hatching and then decreased until 3-5 days of age. Thereafter, BGP levels in bone and serum increased gradually until 8 weeks of age. These changes of BGP levels were well correlated with those of serum calcium and inorganic phosphorus concentrations, serum alkaline phosphatase activity and bone calcium content. The molecular size of increased serum BGP at hatching was not different from that of bone BGP. These results suggest that BGP plays a role in hatching and bone formation during chick development.

1-Carboxyglutamic Acid↗
PubMed1983

[Suppression of puerperal lactation by metergoline].

Suppression of puerperal lactation by a potent serotonin antagonist, metergoline was studied in 33 puerperal women, i.e., abortion after sixteen weeks of gestation 6, premature labor 13, labor at term 13, and hydatiform mole 1. The drug was administered orally at a dose of 4 mg bid for 5 days to 26 subjects, starting within one week from delivery (group A). The remaining 7 subjects received 4 mg of metergoline bid for 7 days after more than 2 weeks from delivery (group B). Lactation was either rapidly suppressed or prevented in 22 out of the 26 subjects in group A and in all subjects in group B. After the therapy was stopped, rebound phenomena were observed in 4 subjects in group A and in 2 subjects in group B, but a further 5-7 days' treatment with metergoline produced satisfactory results. The mean plasma prolactin levels, studied in 10 subjects in group A at hourly intervals after the first metergoline dose, decreased significantly one hour later (p less than 0.05) and reached the nadir level, 19.9 +/- 2.6% of the mean basal value, 4 hours later. The daily plasma prolactin levels in 9 subjects were significantly lower than those of the control group during metergoline treatment (p less than 0.001). No side effects of metergoline medication were observed. Metergoline for a short course of administration is very effective in the suppression of puerperal lactation. In case of the suppression of lactation after the second week of puerperium, 10-14 days of metergoline treatment is recommended to avoid the rebound phenomena.

Adult↗
PubMed1982

Mechanism of inhibitory effect of unavailable carbohydrate on intestinal calcium absorption.

The effect of unavailable carbohydrates on the intestinal absorption of calcium was studied in rats raised for 7 or 8 weeks on diets containing 10 or 20% of cellulose, glucomannan, or pullulan. The following results were obtained a) Body weight gain was diminished more severely in glucomannan groups than in cellulose groups. b) Serum calcium levels were slightly lower in all groups fed unavailable carbohydrates, whereas serum inorganic phosphorus levels were similar to that of the control group. c) There was a significant reduction of bone ash from rats fed glucommanan or cellulose with 620 glycoside bonds. d) Calcium transport measured in the everted duodenal sac remarkable decreased in the glucomannan 20% group, but slightly increased in the cellulose groups. e) Calcium binding activity was lowered significantly in all groups fed unavailable carbohydrates. f) Alkaline phosphatase and sucrase activities in the duodenum were also markedly decreased by prolonged intake of unavailable carbohydrates. These results indicate that inhibitory effect of unavailable carbohydrates on intestinal calcium absorption is partially due to the loss of calcium binding protein caused by gastrointestinal transit of large amounts of undigested substances.

Animals↗
PubMed1982

Effect of sucrose and Acarbose feeding on the development of streptozotocin-induced diabetes in the rat.

The effects of sucrose and Acarbose (alpha-glucosidase inhibitor) feeding on the development of diabetes were studied in streptozotocin-treated rats. Rats were raised on four different dietary regimens, viz, a sucrose diet (46% of the total weight in the form of sucrose, 24% as starch), a starch diet (70% as starch), a standard diet (laboratory chow: Oriental Yeast Co.) or an Acarbose diet (a standard diet containing 75 mg Acarbose/100g diet) for a week followed by an intraperitoneal injection of streptozotocin (70 mg/kg). Development of diabetes was determined by urinary and blood glucose levels (more than 250 mg/dl). The incidence of diabetes in the groups of rats fed on sucrose, starch, standard, and Acarbose diets was 100%, 80%, 70% and 47.6%, respectively. The development of diabetes was accelerated by sucrose feeding and depressed by Acarbose feeding. There was mild diabetes in rats fed on Acarbose diet. The sucrose feeding caused a marked increase of disaccharidase activities in the proximal part of the intestine and in the apical part of the villus-crypt gradient of epithelial cells. The Acarbose feeding caused a significant decrease of disaccharidase activities. The changes in protein content of the sucrase-isomaltase complex appeared to be in parallel with those of disaccharidase activities. These results suggest that intestinal disaccharidase activities are involved in the development of experimental diabetes induced by streptozotocin.

Acarbose↗
PubMed1982

Calcium-binding proteins in bovine milk: calcium-binding properties and amino acid composition.

The Ca2+-binding properties and amino acid compositions of two calcium-binding proteins (mCaBP-3 and mCaBP-4) purified from bovine milk were studied. mCaBP-3 was identified as a Ca2+-bound type and mCaBP-4 as a Ca2+-free type by means of ion-exchange chromatography on a DEAE-Sephadex A-25 column. In polyacrylamide gel disc electrophoresis, both mCaBP-3 and mCaBP-4 had the same mobility of Rf = 0.73 and the addition of 5 mM CaCl2 to the electrode buffer decreased the mobility from Rf = 0.73 to Rf = 0.49. mCaBP-3 and mCaBP-4 consisted of 120 and 122 amino acid residues, respectively. The molecular weights were 13,758 and 13,967, respectively. The amino acid compositions of the two milk CaBPs very closely resembled each other. Both milk CaBPs were rich in aspartic acid, glutamic acid, leucine and lysine, but did not contain trimethylated lysine and amino sugar. An interesting feature is that each milk CaBP contained eight cysteine sulfone and three tryptophan residues per molecule. From these results, it is suggested that mCaBP-3 and mCaBP-4 are identical protein and that mCaBP-3 is formed from mCaBP-4 by means of a conformational change by binding of Ca2+. Thus, mCaBP-3 is a holoprotein and mCaBP-4 is an apoprotein. Furthermore, it is suggested that milk CaBP is different from calmodulin, troponin C and vitamin D-dependent calcium-binding protein.

Amino Acids↗