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Biomedical subjects

T Handa

Publications and source records attributed to T Handa.

At least 109 records · Page 6Linked to original sources
PubMed1985

Interaction of differently oriented lipids in monolayer: mixed monolayers of 16-(9-anthroyloxy)palmitic acid with phosphatidylcholine and cholesterol.

16-(9-Anthroyloxy)palmitic acid (16-AP) is a bifunctional molecule with carboxyl and 9-anthroyloxy groups attached at both ends of the hydrocarbon chain. At the air-water interface, in a monolayer, the 16-AP molecule has horizontal and vertical orientations, depending on the surface pressure of the monolayer. The miscibilities of 16-AP with dimyristoylphosphatidylcholine (DMPC), cholesterol (CH), and fatty acids in mixed monolayers were evaluated in investigations of monolayer phase transitions. Lipid molecules with flexible hydrocarbon chains, i.e., DMPC and fatty acids, formed homogeneous mixed monolayers with horizontally oriented 16-AP. On the other hand, the rigid molecule, CH, could not accommodate the horizontally oriented 16-AP in a monolayer, and there was a phase separation from 16-AP. In biological and reconstituted membranes, preferential binding of phospholipid to the integral protein and exclusion of cholesterol in close vicinity of the membrane protein have been recognized. On the basis of this work, it can be expected that flexible lipids readily accommodate the rough hydrophobic surface of integral proteins and stabilize the structure of the protein, while rigid lipids such as cholesterol are removed from the immediate environment of the membrane protein, if the protein does not interact specifically with the rigid lipids.

Calorimetry↗
PubMed1985

Novel method for the preparation of controlled-release theophylline granules coated with a polyelectrolyte complex of sodium polyphosphate-chitosan.

A novel method for the preparation of theophylline granules coated with a polyelectrolyte complex of sodium tripolyphosphate and chitosan was developed. The theophylline granules containing sodium tripolyphosphate were stirred in an HCl solution of chitosan. During the mixing, the dissolved sodium tripolyphosphate in the granule moved to the surface and reacted with the chitosan, resulting in the formation of the polyelectrolyte complex film. The factors affecting the drug content, the particle size, and the coating-film thickness of the resultant coated granules were determined. The theophylline content in the coated granule decreased with increasing content ratio of sodium tripolyphosphate to theophylline in the original granule and with increasing chitosan concentration in the coating solution. The coated granule size increased with increasing chitosan concentration in the coating solution and with decreasing agitation speed. The coating-film thickness increased with an increase in the chitosan concentration, the pH of the coating solution, and the sodium tripolyphosphate to theophylline content ratio in the original granule. The drug-release pattern of the coated granules followed zero-order kinetics and the release rates were significantly reduced compared with that of the original granule.

Chemical Phenomena↗
PubMed1985

Preparations of agglomerated crystals of polymorphic mixtures and a new complex of indomethacin-epirizole by the spherical crystallization technique.

Agglomerated crystals of indomethacin and epirizole were prepared by the spherical crystallization technique. The solvent used was ethanol-water-chloroform, ethyl acetate-water, or ethyl acetate-aqueous sodium chloride. From the ethanol-chloroform-water system, we obtained agglomerated crystals of a polymorphic mixture of the beta form of indomethacin (original form, gamma) and amorphous epirizole. When the mole percent of epirizole loaded into the system was less than 63 and 38% for the ethyl acetate-water and ethyl acetate-aqueous sodium chloride systems, respectively, the agglomerated crystals consisted of a polymorphic mixture of the alpha form of indomethacin and amorphous epirizole. When the respective mole percent of epirizole loaded was more than 65 and 43% in the aforementioned systems, a new complex of indomethacin-epirizole (molecular ratio equal to 2:1) was obtained. Recovery of complex from the drugs loaded in the ethyl acetate-aqueous sodium chloride system was higher than that in the ethyl acetate-water system, as a result of a salting-out effect. The solubility of indomethacin in the agglomerated complex in a solution of 30% aqueous ethanol and in disintegration test solution no. 2 (composition, 0.05 M KH2PO4 plus 0.0236 M, NaOH, pH 6.8), specified in the Japanese Pharmacopeia X (JPX), was higher than in the physical mixture (molecular ratio of indomethacin to epirizole equal to 2:1). In the ethanol solution, indomethacin was transformed into the gamma form during dissolution, and a decrease in solubility occurred. The process of dissolution of the tablet of the agglomerated complex was described by zero-order kinetics.(ABSTRACT TRUNCATED AT 250 WORDS)

Calorimetry, Differential Scanning↗
PubMed1983

[Effect of adenosine triphosphate-magnesium chloride administration for post-ischemic acute renal failure (I)].

Models of post-ischemic acute renal failure were prepared in rats. The effects of adenosine triphosphate-magnesium chloride (ATP-MgCl2) administration following renal ischemia on possible changes in renal function and renal cellular metabolism following ischemia were studied using the model. The results obtained revealed the following: 1) Over 40 minute-renal ischemia led to significant lowerings of renal cellular ATP level and energy charge (EC) by as much as 45 to 57% and 4.1 to 7.4% of the control, respectively, at 90 min following re-establishment of renal blood flow. Significant increases in Na+ in renal tissues were observed, but no changes in K+. Further, lactate level in renal tissues tended to increase with prolonged ischemic time by as much as 27 to 31% of the control, with a renal cellular anaerobic metabolism observed. On the other hand, at 24 hr following recirculation of the kidney, plasma creatinine (P-Cr), blood urea nitrogen (BUN) and fraction excretion of sodium (FENa) increased significantly, and creatinine clearance (C-Cr) and urine osmotic pressure decreased significantly, as compared with the control, indicating ischemic acute renal failure. 2) Intravenous injection of ATP-MgCl2 at a dose of 25 mumole/kg and a rate of 1.0 mumol/min after 40 min of renal ischemia led to significant lowerings of P-Cr, BUN and FENa to 36, 35 and 35% of the control (injected with physiological saline solution), respectively, and to significant elevation of C-Cr and urine osmotic pressure by as much as 41 to 31% of the control respectively, at 24 hr after reperfusion. The above results suggested that the ischemic acute renal failure was caused by the decreases in renal cellular ATP and EC with ischemia, resulting in renal cellular metabolic disturbances. It was further suggested that ATP-MgCl2 administered for such a pathological condition could make significant improvements in renal function.

Acute Kidney Injury↗
PubMed1982

Acid mucopolysaccharide (AMPS) abnormality in multiple sulfatase deficiency: chemical compositions of AMPS in urine and liver.

Extensive chemical analyses of acid mucopolysaccharides (AMPS) were carried out in the urine and tissue (liver and brain) from a Japanese patient and two European patients with multiple sulfatase deficiency (MSD). The Japanese patient with MSD contained excessive quantities of heparan sulfate and moderately increased chondroitin sulfate A/C. Urinary excretion of AMPS in MSD heterozygotes was increased 2-fold compared to our controls. The urinary pattern of AMPS in the mother of the MSD patient showed an increase of 18% heparan sulfate and 36% dermatan sulfate whereas the urinary excretion pattern in the father was increased 21% for heparan sulfate as contrasted to controls (chondroitin sulfate A, 50-52%; chondroitin sulfate C, 38-46%; and heparan sulfate, 3-10%). Seventy-five % of the AMPS and the MSD liver was heparan sulfate rather than dermatan sulfate. The degree of accumulation of AMPS in the MSD liver was 30-50 times that of the control. Cerebral gray matter from the MSD patient contained 30-40 times that of control (relative increase of heparan and dermatan sulfate) whereas only a 5-fold increase was observed in white matter. It seems that a major site of accumulated AMPS appears to be in the gray matter. Carbohydrate analysis of the AMPS obtained from MSD urine and tissues was performed by: enzyme digestion with testicular hyaluronidase, heparitinase and chondroitinase ABC, cellulose acetate electrophoresis, Dowex-1 column chromatography and amino sugar analysis by amino acid analyzer. These findings indicate that the major accumulated AMPS in MSD urine and liver is heparan sulfate and thus, the predominant AMPS metabolic defect in MSD is heparan sulfate degradation.

Brain Chemistry↗