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Biomedical subjects

H Takahata

Publications and source records attributed to H Takahata.

32 records · Page 2Linked to original sources
PubMed1998

The distribution of protein associated with poly(DL-lactide co-glycolide) microparticles and its degradation in simulated body fluids.

Poly(lactide co-glycolide) (PLG) microparticles with a mean size of less than 2 microns, prepared by the water-in oil-in water method, exhibited a maximum surface protein (ovalbumin) content in excess of 50% of the total loading. The surface-core distribution was found to be sensitive to stabiliser concentration and the type of albumin used in the formulation. The degradation of OVA was monitored following incubation of microparticles for 14 days in PBS and for 2 h in simulated gastric and intestinal fluids, respectively. OVA removed from the surface of particles, following incubation in PBS, was found to be intact as measured by SDS-PAGE. After 7 days in PBS at 37 degrees C, protein extracted from the microparticles was found to be partly hydrolysed with the prevalence of an antigen fragment at 36.1 kDa. The relative amount of intact OVA in 50:50 PLG microparticles decreased more rapidly than in the slower degrading 75:25 PLG microparticles. Importantly, the degradation of extracted OVA over 14 days was similar for microparticles incubated either with regular changes of release medium or in a dialysis tube. Almost all the OVA encapsulated in PLG microparticles remained intact after incubation in simulated gastric and intestinal media for 2 h. In contrast, the surface protein was rapidly degraded by trypsin and pepsin and was not detected by SDS-PAGE.

Body Fluids↗
PubMed1996

A case of herpes zoster associated with colitis.

A 58-year-old Japanese woman who had herpes zoster in association with colitis was successfully treated with intravenously administrated acyclovir. Vesicular lesions with red haloes ranged from the left side of her buttock to the left extremity, corresponding to the L4 to S2 dermatomes. Her colitis was considered to have been induced by varicella-zoster virus, based on the facts that the clinical courses were correlated and that the innervation of the affected site of the colon corresponded to an infected dermatome (S2).

Acyclovir↗
PubMed1992

Enhancement of host defense by Y-25510, (+-)-3-[4-(2-dimethylamino-1-methylethoxy)phenyl]-1H-pyrazolo[3,4 -b] pyridine-1-acetic acid, a novel synthetic compound. A comparison with recombinant human granulocyte colony-stimulating factor in 5-fluorouracil-treated mice.

The effect of a novel synthetic compound, Y-25510, (+-)-3-[4-(2-dimethylamino-1-methylethoxy)phenyl]-1H-pyrazolo[3,4 -b] pyridine-1-acetic acid, on recovery from long-lasting leukopenia induced by 5-fluorouracil was compared with that of recombinant human granulocyte colony-stimulating factor (rhG-CSF). When mice were administered i.p. with 5-FU (200 mg/kg) on days 0 and 7, intravenous administration of Y-25510 (100 and 1000 micrograms/kg) prevented the decrease in the peripheral leukocyte and neutrophil number and accelerated the recovery from leukopenia. Subcutaneous administration of rhG-CSF (50 micrograms/kg) did not prevent leukopenia but accelerated the recovery from leukopenia. In particular, peripheral neutrophil number increased over a normal level. The administration of Y-25510 (10, 100 and 1000 micrograms/kg) restored the decrease in the number of bone marrow cells, spleen cells, lymphocytes, neutrophils and monocytes. The administration of rhG-CSF (50 micrograms/kg) restored the decrease in the number of bone marrow cells, spleen cells, and neutrophils but not that of lymphocytes and monocytes. In fractions of bone marrow cells on day 21, the administration of Y-25510 (1000 micrograms/kg) showed a tendency of restoring the decrease in neutrophil number. In conclusion, the administration of Y-25510 prevented leukopenia and accelerated the recovery from leukopenia in the 5-FU-treated mice. It is suggested that the mechanism of the restorative action of Y-25510 is different from that of rhG-CSF. In a number of immature bone marrow cells Y-25510 has a potent stimulatory effect on the recovery from the decrease in number of hematopoietic cells, keeping a balance in number of each blood cell.

Adjuvants, Immunologic↗
PubMed1992

Gastric emptying rate of drug preparations. III. Effects of size of enteric micro-capsules with mean diameters ranging from 0.1 to 1.1 mm in man.

The gastric emptying rates of three enteric micro-capsule preparations with mean diameters of 1.1 mm and less (1.1, 0.5 and 0.1 mm) were compared. The gastric emptying rate was evaluated by determining the pharmacokinetic parameters of pyridoxic acid, including Vmax (peak excretion rate) and Tmax (time to reach peak excretion rate) after oral administration of micro-capsules containing pyridoxal phosphate as a marker drug to five healthy subjects. When given under fasting conditions, the gastric emptying rates of these preparations, according to Tmax, differed significantly; the preparations with smaller particle sizes were emptied from the stomach at a faster rate than those with larger particle sizes. However, under non-fasting conditions the gastric emptying rates were virtually the same, regardless of particle size, and all the preparations were emptied from the stomach at a much slower rate than when administered under fasting conditions.

Adult↗
PubMed1992

[Asymmetric synthesis of nitrogen-containing biologically active compounds utilizing intramolecular aminocyclization to olefin of secondary allylic alcohols].

The progress of the asymmetric syntheses of nitrogen-containing biologically active compounds such as pyrrolidine, pyrrolizidine, indolizidine alkaloids, and unusual amino acids has been reviewed. Our recent advances in taking advantage of stereoselective aminocyclization of homochiral N-alkenyl urethanes and thioimitates containing allylic hydroxyl group have provided an attractive entry into the functionalized pyrrolidine skeletons as chiral building blocks. A promising approach to a number of biologically active compounds such as alkaloids has emerged.

1-Propanol↗
PubMed1984

Enhanced intestinal absorption of amino acids and amino acid-like drug by possible formation of enamine in administered solution by the presence of ethylacetoacetate.

Ethylacetoacetate promoted the colonic and the jejunal absorption of amino acids such as L-phenylalanine and D-phenylalanine when administered in aqueous solution. Enhanced absorption of these isomers of amino acid might occur via a formation of enamine, which was observed in aqueous solution by monitoring ultraviolet absorbance at 288 nm. Since mixture of L- or D-phenylalanine and ethylacetoacetate in aqueous solution enhanced colonic absorption of cefmetazole while the solution did not affect so much on the jejunal absorption of cefmetazole compared to the colonic absorption of it, enhancing action of enamine probably produced in aqueous solution may be more effective at the colonic compartment.

Acetoacetates↗