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Biomedical subjects

R Kasai

Publications and source records attributed to R Kasai.

At least 91 records · Page 5Linked to original sources
PubMed1991

Studies on Balanites aegyptiaca fruits, an antidiabetic Egyptian folk medicine.

An aqueous extract of mesocarps of the fruits of Balanites aegyptiaca exhibited a prominent antidiabetic activity by oral administration in streptozotocin induced diabetic mice. From one of the active fractions of this extract, two new steroidal saponins were isolated, and their structures were determined as 26-O-beta-D-glucopyranosyl-(25R)-furost-5-ene-3 beta,22,26-triol 3-O-[alpha-L-rhamnopyranosyl-(1----2)]-[beta-D-xylopyranosyl-(1---- 3)]-[alpha-L-rhamnopyranosyl-(1----4)]-beta-D-glucopyranoside and its 22-methyl ether. In addition, two known saponins, 26-O-beta-D-glucopyranosyl-(25R)-furost-5-ene-3 beta,22,26-triol 3-O-(2,4-di-O-alpha-L-rhamnopyranosyl)-beta-D-glucopyranoside and its methyl ether were isolated and identified. It was revealed that the individual saponins did not show antidiabetic activity, while the recombination of these saponins resulted in significant activity. From an ethanolic extract of the epicarps, two known flavonol glycosides, isorhamnetin-3-O-robinobioside and isorhamnetin-3-O-rutinoside were isolated and identified.

Animals↗
PubMed1991

Solubilization of steviolbioside and steviolmonoside with gamma-cyclodextrin and its application to selective syntheses of better sweet glycosides from stevioside and rubusoside.

1,4-alpha-Glucosylation at the 13-O-glycosyl moiety of stevioside (S) and rubusoside (RU) results in a significant increase of sweetness. Saponification of the 19-COO-beta-glucosyl linkage of S and RU yielded steviolbioside (SB) (= 13-O-beta-sophorosyl-steviol) and steviolmonoside (SM) (= 13-O-beta-glucosyl-steviol), respectively, both of which are poorly soluble in an acetate buffer. It was found that the solubilities of SM and SB in the buffer solution were remarkably increased in the presence of gamma-cyclodextrin (gamma-CD). SB was solubilized in the buffer solution with the aid of gamma-CD, and the solution was subjected to 1,4-alpha-transglucosylation by using a cyclodextrin glucanotransferase-starch system to give a mixture of products which were glucosylated at the 13-O-glycosyl moiety. This mixture was acetylated, and the acetate was subjected to chemical beta-glucosylation of 19-COOH followed by deacetylation to afford compounds which have superior sweetness to S. In the same way, derivatives with superior sweetness were selectively prepared from RU through SM.

Cyclodextrins↗
PubMed1991

Further study on the 1,4-alpha-transglucosylation of rubusoside, a sweet steviol-bisglucoside from Rubus suavissimus.

Rubusoside (the beta-D-glucosyl ester of 13-O-beta-D-glucosyl-steviol), which is the major sweet principle of leaves of Rubus suavissimus S. Lee, was subjected to 1,4-alpha-transglucosylation by the cyclodextringlucanotransferase-starch system (the CGTase system). The tri- and tetra-glucosylated products were isolated together with the mono- and di-glucosylated products, which had already been isolated. A prominent increase in intensity of the sweetness was observed for the compounds which were di- and tri-glucosylated at the 13-O-glucosyl moiety. This result further substantiated the structure-sweetness relationship for 1,4-alpha-glucosylated compounds of steviol-glycosides reported previously. For protection of the 19-COO-glucosyl moiety against glucosylation by the CGTase system, the 4-hydroxyl group of the 19-COO-glucosyl moiety was beta-galactosylated by the beta-galactosidase-lactose system. This galactosylated compound was subjected to a regio-selective glucosylation of the 13-O-glucosyl moiety by the CGTase system, which was followed by enzymic elimination of the galactosyl group to furnish an exclusive preparation of the improved sweeteners just mentioned.

Carbohydrate Sequence↗
PubMed1991

Enzymic production of sweet stevioside derivatives: transglucosylation by glucosidases.

For the purpose of improving sweetness and a further study on the structure-sweetness relationship of steviol glycosides, transglycosylation of stevioside by a variety of commercial glucosidases was investigated. It was revealed that two alpha-glucosidases gave glucosylated products. Transglucosylation of stevioside by Pullulanase and pullulan exclusively afforded three products, 13-O-[beta-maltotriosyl-(1----2)-beta-D-glucosyl]-19-O-beta-D-g luc osyl- steviol (1), 13-O-[beta-maltosyl-(1----2)-beta-D-glucosyl]-19-O-beta-D-glucosyl- steviol (2) and 13-O-beta-sophorosyl-19-O-beta-maltotriosyl-steviol (3). All of these products have already been obtained by trans-alpha-1,4-glucosylation of stevioside by the cyclodextrin glucanotransferase starch system, and 1 and 2 have been proven to be tasty and potent sweeteners. Transglucosylation of stevioside by Biozyme L and maltose afforded three new products, 4, 5 and 6, the structures of these compounds being elucidated as 13-O-beta-sophorosyl-19-O-beta-isomaltosyl-steviol (4), 13-O-[beta-isomaltosyl(1----2)-beta-D-glucosyl]-19-O-beta-D-glucosyl- steviol (5) and 13-O-[beta-nigerosyl-(1----2)-beta-D-glucosyl]-19-O-beta-D- glucosyl-steviol (6). A significantly high quality of taste was evaluated for 4.

Carbohydrate Sequence↗
PubMed1990

Bone blood flow after spinal paralysis in the rat.

The goal of this study was to investigate the acute and chronic effects of paralysis induced by spinal cord section or sciatic neurotomy on bone blood flow in the rat. Regional bone blood flow was measured in the early stage with the hydrogen washout technique and the change of whole bone blood flow was measured in the early and the late stages with the radioactive microsphere technique. Four to 6 h after cordotomy at the level of the 13th thoracic vertebra, the regional bone blood flow in the denervated tibia increased significantly (p less than 0.01). After hemicordotomy with rhizotomy at the same level, the regional bone blood flow in the denervated tibia increased significantly (p less than 0.05) 6 h postoperatively. The whole bone blood flow in the denervated tibia had also increased significantly (p less than 0.05) at 6 h and at 4 and 12 weeks postoperatively. After sciatic neurotomy, the regional and the whole bone blood flow in the paralytic tibia did not change significantly. The present study demonstrated that monoplegic paralysis caused an increase in bone blood flow in the denervated hind limb from a very early stage. It was suggested that the spinal nervous system contributed to the control of bone blood flow.

Animals↗
PubMed1990

Effect of dietary cadmium and/or copper on the bone lysyl oxidase in copper-deficient rats relative to the metabolism of copper in the bone.

Effects of cadmium (Cd) on lysyl oxidase activity and copper (Cu) metabolism in bone were studied using Cu-deficient rats supplemented with Cu and/or Cd in a diet. When fed for 8 weeks on a diet containing 0.3 ppm or less Cu (-Cu diet), weanling rats revealed anemia, and markedly decreased plasma ceruloplasmin activity and serum Cu to less than 15% of normal level, showing features of Cu-deficiency. These rats were divided into four groups and refed for another 2 weeks on the following diets: Group I, -Cu diet; Group II, -Cu diet with 50 ppm Cd (+Cd diet); Group III, -Cu diet supplemented with 15 ppm Cu (+Cu diet); group IV, -Cu diet with both Cu and Cd (+Cu/+Cd diet). After 2 weeks, serum Cu levels of Groups I, II, III and IV were 1.8, 0.8, 78 and 74% of the normal control level (1.438 +/- 0.060 micrograms/ml), respectively. Concentrations of Cu in epi- and metaphyses of the control group, Groups I, II, III and IV were 1.45 +/- 0.20, 0.67 +/- 0.08, 0.76 +/- 0.12, 1.40 +/- 0.31 and 1.22 +/- 0.05 micrograms/g wet tissue, in that order. Concentrations of Cd in epi- and metaphysis increased in only Groups II and IV and were 0.15 +/- 0.03 and 0.18 +/- 0.01 micrograms/g wet tissue, respectively. Thus, having both Cd and Cu supplements in a diet did not inhibit each other's uptake into the tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Oxidoreductases↗
PubMed1990

Restoration of axial and appendicular bone volumes by h-PTH(1-34) in parathyroidectomized and osteopenic rats.

Effects of h-PTH(1-34) were histomorphometrically evaluated in both cancellous and cortical bone tissues of axial and appendicular skeletons of parathyroidectomized and osteopenic rats. Osteopenia was induced by hemicordotomy immobilization and by estrogen depletion as a result of ovariectomy. The rats received intramuscular injections of 50 units (15 micrograms) of h-PTH(1-34) six times weekly during weeks 11 through 18 of the experiment. Significant restoration of cancellous and cortical bone volumes was observed in axial and appendicular skeletons of animals treated with h-PTH(1-34). The stimulatory effects of h-PTH(1-34) on osteoid surface, independent of eroded surface, in cancellous and cortical bone tissues, were clearly observed histomorphometrically. Mineralizing surface, mineral apposition rate and bone formation rate in cancellous bone tissues were markedly increased by h-PTH(1-34). It should be noted that h-PTH(1-34) increased trabecular thickness, but did not increase trabecular number. In conclusion, h-PTH(1-34) stimulated bone formation independent of bone resorption, and restored cancellous and cortical bone volumes in parathyroidectomized and osteopenic rats.

Animals↗
PubMed1990

[Solubilizing effect and inclusion reaction of cyclic bisdesmosides from tubers of Bolbostemma paniculatum].

Tubeimosides I, II and III (cyclic bisdesmosides) have been isolated from Chinese cucurbitaceous crude drug Tu-bei-mu, a tuber of Bolbostemma paniculatum (Maxim.) Franquet. Solubilizing effects of these cyclic bisdesmosides on water insoluble or less-soluble compounds were examined. It was revealed that cyclic bisdesmosides were effective on increasing the solubility of Yellow OB, dl-alpha-tocopherol and saponin A from Sapindus mukurossi. The critical micell concentration (cmc) and association number as well as diameter of micell of tubeimoside I in water were also measured. The interaction of tubeimoside I with 1-anilino-8-naphthalene-sulfonate (ANS) in aqueous solution was investigated photometrically. It was observed that tubeimoside I strongly enhanced the intensity of fluorescence of ANS, suggesting the significant formation of inclusion complex.

Drugs, Chinese Herbal↗
PubMed1990

[Evaluation of latent cardiac disease in diabetic patients with Tl-201 exercise myocardial scintigram and blood pool scintigram].

To find latent heart disease in diabetic patients, 142 diabetic patients were divided into 4 groups: 1) No hypertension and normal ECG (DM group); 2) Hypertension recognized clinically (HT group); 3) Myocardial damage on ECG (MD group) 4) group associated with the previous 2 (HT + MD group). In all groups Tl-201 exercise myocardial scintigrams and blood pool scintigrams were taken for comparative analysis. Positive rates of SPECT were 27.7% (23/83) in the DM group, 30.0% (9/30) in the HT group, 50.0% (6/12) in MD group, and 70.6% (12/17) in the HT + MD group. The rate in the HT + MD group was significantly higher than in that of the DM and HT groups (p less than 0.001, p less than 0.01). Blood pool scintigrams revealed that in the HT + MD group, as compared with the normal control group, both 1/3 FF and PFR were significantly depressed, in addition to significant TPF prolongation in the former (p less than 0.001, p less than 0.05, p less than 0.05). These findings suggest that in diabetic patients hypertension and myocardial damage would lead to a high incidence of abnormality in SPECT and left ventricular rapid filling dysfunction. This indicate a high incidence of latent cardiac disease which can be recognized in diabetic patients by stress myocardial and blood pool scintigrams.

Adult↗
PubMed1989

Transforming growth factor beta modulates proliferation of osteoblastic cells: relation to its effect on receptor levels for epidermal growth factor.

The effect of transforming growth factor beta (TGF-beta) on cellular proliferation of osteoblastic MC3T3-E1 cells was studied with particular emphasis on its effect on modulation of epidermal growth factor (EGF) receptors. In other cells, TGF-beta has been reported to augment EGF receptors. Exposure of MC3T3-E1 cells to TGF-beta initially increased cell surface EGF receptor levels and decreased the rate of DNA synthesis. The initial elevation of EGF receptor levels was due to increased receptor number per cell, not to changes in binding affinity. On the contrary, prolonged exposure (longer than 40 h) resulted in a decrease in EGF receptor and an increase in the rate of DNA synthesis. Thus, the effects of TGF-beta on these cells appears to be biphasic, reflecting complex mechanisms of action; the early effects of TGF-beta may be consistent with cellular differentiation to the osteoblastic phenotype with decreased cellular proliferation, whereas chronic exposure of these cells to TGF-beta stimulated cellular proliferation and inhibited osteoblastic phenotype expression. It is not likely that stimulation of cellular proliferation was through elevation of EGF receptor levels, because TGF-beta did not enhance the stimulatory effect of EGF on cellular proliferation. Thus, we conclude that TGF-beta possesses a stimulatory effect on the cellular proliferation of osteoblastic MC3T3-E1 cells independent of its modulative effect on EGF receptor level.

Alkaline Phosphatase↗
PubMed1989

Effect of (Asu1,7)-eel calcitonin on the prevention of osteoporosis induced by combination of immobilization and ovariectomy in the rat.

Experimental osteoporosis was induced in the rat by a combination of ovariectomy and immobilization by hemicordotomy. (Asu1,7)-eel calcitonin (CT) was administered at doses of 0.1, 0.5, 1.0, 2.5, and 5.0 MRC unit/kg, and its preventive effect on bone loss was examined. Significant bone loss was observed in the untreated control group by photo-densitometry and measurement of bone mass. CT at doses of above 1.0 MRC unit/kg significantly increased femur scores and at doses of above 2.5 MRC unit/kg resulted in significantly higher photodensity. Dry weight and ash weight were significantly higher in the 2.5 and 5.0 MRC unit/kg CT-treated groups. Administration of CT had a nearly dose-dependent effect on bone mass. Histomorphometry revealed significantly lower fractional formation surface and fractional resorption surface in the 5.0 MRC unit/kg CT-treated group. Bone mineralization was studied by the quantitative analysis of tetracycline incorporation. Tetracycline uptake was significantly lower in the groups treated with CT at doses above 1.0 MRC unit/kg. The kinetic bone formation activity studied by 45Ca and 14C-proline tracer examination, in the 5.0 MRC unit/kg CT-treated group was significantly lower than that in the control group, but not lower than that in the sham-operated group.

Animals↗
PubMed1989

Saponins from leaves of Kalopanax pictum var. maximowiczii, a Korean medicinal plant.

From leaves of Kalopanax pictum var. maximowiczii, a Korean medicinal plant, six known saponins of hederagenin were isolated. One of the monodesmosides was identified as sapindoside A, previously isolated from Sapindus spp. Another monodesmoside and four bisdesmosides were proved to be identical with saponins-K3, -K10 and -K12 and Kizuta saponins-K8 and -K11, respectively, all of which have been isolated from Hedera rhombea. It was observed that the water solubilities of these monodesmosides were increased in the presence of the co-occurring bisdesmosides. The relationship between structure and solubilizing effect is reported.

Animals↗
PubMed1989

Reticuloendothelial system-activating polysaccharides from rhizomes of Panax japonicus. I. Tochibanan-A and -B.

From rhizomes of Panax japonicus (Araliaceae), two polysaccharides named tochibanan-A and -B, which show reticuloendothelial-potentiating activity in the carbon clearance test in mice, were isolated. The structure of tochibanan-A (molecular mass: 23,000) was elucidated as a linear beta-1,4-D-galactan. Tochibanan-B (molecular mass: 40,000) consists of D-galactose (87.1%), L-arabinose, D-glucose and D-galacturonic acid and has a beta-D-(1----4)-linked galactopyranosyl backbone possessing GalA-(1----6)-Gal, Ara-(1----5)-Ara, Gal, and Glc side chains. The structure around the branching points and the repeating unit were investigated and a possible structure of tochibanan-B is proposed.

Animals↗