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Biomedical subjects

M Hashida

Publications and source records attributed to M Hashida.

At least 73 records · Page 4Linked to original sources
PubMed1986

Changes in D-glucose uptake by brush-border vesicles from small intestine of rats treated with mitomycin C.

The effect of mitomycin C pre-administration on the D-glucose transport system in the intestinal brush-border membrane of rat small intestine was examined by a rapid filtration technique. Forty-eight hours following the intravenous administration of mitomycin C, there were extensive and severe mucosal derangements. At this time point, membrane vesicles were prepared from the mitomycin-C-pretreated and control rats. Binding studies indicated that D-glucose entered into the intravesicular space of vesicles even in the case of mitomycin-C-pretreated rats. Vesicles obtained from both the mitomycin-C-pretreated and the control rats showed sodium-dependent uptake of D-glucose, but the initial uptake at 15 sec was significantly greater in control rats than in mitomycin-C-pretreated rats. Comparison of kinetic parameters of D-glucose transport indicated that Km was not significantly different between control and mitomycin-C pretreated rats. The pretreatment with mitomycin C decreased Vmax and increased the diffusional permeability to D-glucose considerably. These changes induced by mitomycin C seemed to derive not from a direct effect on mature enterocytes but from an indirect effect secondary to mitotic inhibition in the crypts.

Animals↗
PubMed1986

Characterization of liposomes and an emulsion containing mitomycin C or lipophilic mitomycin C prodrugs.

The characteristics of liposomes and an oil-water emulsion containing either mitomycin C (MMC) or its lipophilic prodrugs were investigated. Prodrugs were incorporated into liposomes and oil droplets of an oil-water emulsion, and this incorporation was dependent on the lipid content of the liposomes and droplets. A good correlation was observed between the calculated lipid:water partition ratios and partition coefficients in chloroform:water. The prodrugs were rapidly distributed between the lipid and aqueous phases when they were injected into the dispersion medium of empty liposomes and an oil-water emulsion, or when the formulations incorporating prodrugs were diluted with water. Addition of prodrugs to liposomes containing perylene resulted in a decrease of fluorescence. Based on these findings, prodrugs were concluded to be incorporated into lipidic dispersion formulations based on their partitioning behavior. N1a-[(Nonyloxy)carbonyl]MMC (7) showed the highest incorporation into lipidic formulations, while prodrugs with moderate lipophilicities were rapidly released from lipid particles. Liposomes incorporating 7 maintained their multilamellar vesicular form as shown by electron microscopy and by examining their entrapping capacity for water soluble marker dyes. The release of prodrug 7 from both formulations was slow in a buffer solution, but considerable release and conversion to the parent drug were observed when rat plasma was added to the same system. These results suggest that the stability of MMC could be improved by incorporation into lipidic formulations and that a suitable release rate in vivo could be accomplished by use of a prodrug.

Chemical Phenomena↗
PubMed1986

Characterization of mitomycin C-induced gastrointestinal damage: changes in the gastric absorption of drugs in rats.

The effect of mitomycin C (MMC) pre-administration intravenously on the absorption of drugs from rat stomach has been examined by means of the in-situ loop technique. 48 h after the MMC-treatment, the absorption of salicylic acid, aspirin and sulphanilic acid was not influenced but that of sulphanilamide was significantly increased compared with the control. At 96 h, a differential effect of MMC on the absorption of each drug was seen: the absorption of weakly acidic drugs was significantly decreased while that of bases and strong sulphonic acid increased. The decreased absorption of salicylic acid and aspirin correlated with the reduced gastric mucosal blood flow. At 96 h there were severe haemorrhagic lesions in the gastric mucosae. The increase in absorption of poorly absorbed drugs could be ascribed to the increased permeability of the blood-gastric epithelium barrier as was evidenced by leakage of Evans Blue.

Animals↗
PubMed1986

Immunological control of drug absorption from the gastrointestinal tract: the mechanism whereby intestinal anaphylaxis interferes with the intestinal absorption of bromthymol blue in the rat.

Rats were immunized intraperitoneally with ovalbumin and the disappearance of bromthymol blue (BTB) from the intestinal lumen, its accumulation in the tissue, and its net absorption were examined by means of an in-situ recirculation technique during local anaphylaxis. The disappearance of BTB from the intestinal lumen and its net absorption were significantly reduced, but there was no significant effect on its accumulation in the tissue. The pH value of the luminal solution and the perfusate volume were not influenced by intraluminal challenge with the antigen in ovalbumin-immunized rats. In addition, no significant effect was observed on intestinal permeability to BTB in the in-vitro everted sac technique. The intestinal blood flow, measured by a hydrogen clearance method, was not reduced significantly by the intraluminal exposure to antigen. There was enhanced Evans Blue leakage and mucus release in the perfusate after intraluminal challenge with ovalbumin in ovalbumin-immunized rats, but not in non-immunized rats. A significant increase of BTB binding with macromolecular substances in the perfusate was observed during the local anaphylaxis. These findings suggest that the decreased absorption of BTB is due to the interaction with the macromolecular substances in the perfusate during local anaphylaxis.

Anaphylaxis↗
PubMed1986

Effect of temperature on intestinal transfer and tissue uptake of sulfanilamide and aminopropyron in vitro.

The effect of temperature on the transfer and the tissue uptake of sulfanilamide and aminopropyron, an aminopyrine derivative, was investigated using the everted and the non-everted sacs of rat intestine. The M (mucosa) to S (serosa) transfer of sulfanilamide was slightly faster than reverse S-to-M in the ileum at the temperatures studied. Decreased transfer and tissue uptake of sulfanilamide with decreasing temperature were observed using both ileal everted and non-everted sacs. On the contrary, the M-to-S transfer of aminopropyron was slower than the S-to-M transfer in the ileum. The tissue uptake of aminopropyron was almost constant at any temperature in the ileal non-everted sac experiments, while a decreased transfer of aminopropyron was observed with a decrease in temperature. Similar results, like aminopropyron in the ileum, were obtained in the experiments of aminopropyron and sulfanilamide using the colonic sacs. It is concluded that a close relationship may exist between the directional superiority in the transfer and the temperature independency of the tissue uptake.

Aminopyrine↗
PubMed1986

Effect of medium-chain glycerides (MGK) on the intestinal absorption and the hepatobiliary transport of bromthymol blue.

The effect of medium chain glyceride (MGK) emulsion on the intestinal absorption and the biliary excretion of bromthymol blue (BTB) was investigated in rats. Extensive tissue accumulation of BTB was reduced when BTB was administered with MGK emulsion formulation. HCO-100, an emulsifier, was also important for the decrease in the tissue accumulation of BTB. The ratios of absorption percent to tissue accumulation percent and to free fraction, not contained in the droplet of emulsion, in MGK emulsion were much greater than that of the control. Pretreatment with BTB-free emulsion reduced BTB absorption under the control, although tissue accumulation was not affected. The absorption appeared to decrease with increase in the time of pretreatment. The effect of leaving treatment after pretreatment on the absorption of BTB was also investigated. With the increase in leaving time after pretreatment, reduced absorption tended to resume to the level of control. The change in monocaprylate content from 54 to 60% in MGK made a difference in BTB absorption and it was suggested that monocaprylate content in MGK was one of the significant factors of MGK emulsion on drug absorption. Bile recovery study was simultaneously carried out with an in situ recirculation experiment. The recovery of BTB into bile tended to decrease. The ratio of recovery percent of BTB into bile to the absorption percent of BTB also decreased extensively, which is possibly another effect of MGK on drug disposition.

Animals↗
PubMed1986

Cellular interaction and in vitro antitumor activity of mitomycin C-dextran conjugate.

Cellular interaction and in vitro antitumor activity of a polymeric prodrug of mitomycin C (MMC), mitomycin C-dextran conjugate (MMC-D), were studied in relation to its physicochemical characteristics. MMC-D with cationic and anionic charges were examined. The cationic MMC-D was synthesized using a spacer, epsilon-aminocaproic acid and dextrans with molecular weights of 10,000, 70,000, or 500,000 [MMC(C6)Dcat]. The anionic MMC-D was synthesized using 6-bromohexanoic acid as a spacer and dextran with a molecular weight of 70,000 [MMC(C6)Dan]. Cellular adsorption was determined by measuring the concentration of the drug in the medium after incubation with three tumor cell lines, Ehrlich ascites carcinoma, L1210 leukemia, and AH66 ascites hepatoma cells. MMC(C6)Dcat was adsorbed more readily than MMC or MMC(C6)Dan on the tumor cell surface by an electrostatic force. The percentage of adsorption remained almost constant during the course of incubation and no significant difference was observed between the incubation at 4 degrees C and that at 37 degrees C. A corresponding increase in the amounts of MMC(C6)Dcat adsorbed on with higher molecular weights was noted, which conformed to Langmuir's adsorption isotherm. In vitro antitumor activity was evaluated using L1210 and EAC cell culture systems and human tumor colony forming assay. MMC(C6)Dcat showed growth inhibition essentially equal to that of MMC in continuous drug exposure experiments. In a 1-h drug exposure experiment, MMC(C6)Dcat with a molecular weight of 70,000 or 500,000 was more active than MMC, and a good correlation was observed between the effects of MMC(C6)Dcat and the extent of cellular interaction. These results show that cellular interaction played an important role in the manifestation of the antitumor effect of MMC-D and that these phenomena are governed by the physicochemical properties of macromolecular prodrugs, such as electric charge and molecular weight.

Adsorption↗
PubMed1985

A new method for assessment of drug disposition in muscle: application of statistical moment theory to local perfusion systems.

A new experimental system is used to determine exact information concerning local drug disposition. Rabbit hind leg is perfused in situ using a single-pass technique, and outflow curves of drugs are analyzed using statistical moment theory. By the introduction of chromatographic concepts and the application of the well-stirred model to the local perfusion system, physiologically and/or physicochemically meaningful parameters are derived from the first three moments. Moreover, in the assessment, drug disposition is divided into elimination and distribution. The elimination process is also evaluated with respect to rate and extent. This system is used to elucidate the disposition characteristics of mitomycin C and its lipophilic derivative nonyloxycarbonyl mitomycin C.

Animals↗
PubMed1985

Absorption characteristics of the lipophilic prodrug of mitomycin C from injected liposomes or an emulsion.

Mitomycin C (MMC) is amphiphilic and so cannot be incorporated into lipoidal delivery systems. To develop a lipoidal delivery system, its prodrug, nonyloxycarbonyl MMC, was formulated in liposomes and in o/w emulsions and the usefulness of these formulations was evaluated. After injection into the rat thigh muscle, MMC was rapidly absorbed regardless of the dosage form. However, the prodrug was retained at the injection site for considerably longer when formulated in a lipid dispersion system. The accumulation of MMC at regional lymph nodes was also investigated and whereas free MMC arrived at and disappeared from the lymph nodes almost immediately after injection, the prodrug arrived at an early stage and its concentration decreased only gradually, remaining fairly high 2 h after injection. Liposomal lipids appeared to accumulate at the lymph nodes to a greater degree than o/w emulsions. It is suggested that the combination of lipidic carrier devices with lipophilic prodrugs may be a useful adjunct to cancer chemotherapy.

Absorption↗
PubMed1985

Enhanced delivery of mitomycin C derivatives through hairless mouse and rat skins.

The percutaneous permeation characteristics of two lipophilic mitomycin C derivatives with aromatic moieties were determined using excised hairless mouse and rat skins and compared with those of mitomycin C (MMC). 1a-N-Benzylmitomycin C penetrated more readily through both kinds of skin than MMC without metabolic conversion. 1a-N-Benzyloxycarbonylmitomycin C effected a 4-fold increase in the delivery of MMC through the rat skin and was completely converted to MMC by an enzyme in rat skin. However, saturation of the metabolic conversion activity was observed in the hairless mouse skin.

Administration, Topical↗
PubMed1985

Urinary excretion characteristics of a polymeric prodrug of mitomycin C, mitomycin C-dextran conjugate.

Urinary excretion characteristics of a polymeric prodrug of mitomycin C (MMC), mitomycin C-dextran conjugate (MMC-D), following intravenous administration was studied in rats. Three types of MMC-D, conjugates with dextrans of molecular weights of 10000, 70000 and 500000, were tested and urine concentration of MMC, dextran and spacer were determined by three analytical methods, i.e., bioassay, anthrone method and radioactivity counting. MMC was assayed separately as a free form and conjugated form based on antimicrobiological activity. MMC administered as a free form was excreted rapidly into urine but only a small amount of MMC was excreted following the administration of MMC-D. The excreted amount of MMC in a conjugated form varied with the size of carrier dextran while similar sustained excretion was observed regardless of the carrier size. The excretion of carrier dextran determined by anthrone method was confined as the molecular weight was increased. The effect of molecular weight was also observed in the case of spacer-introduced dextran (dextran-C6 spacer) and original dextran. Compared with neutral dextran, cationic MMC-D and anionic dextran-C6 spacer exhibited diminished excretion, indicating the effect of charge on urinary excretion. The urinary recovery of radioactivity was almost in accordance with that of carrier dextran. However, the urinary recovery of MMC based on biological activity was considerably lower than that of carrier dextran. It was suggested that MMC-D underwent inactivation to a great extent before releasing active MMC in the body. The effect of physicochemical properties such as molecular weight and electric charge on the urinary excretion of the polymeric prodrug was thus elucidated.

Animals↗
PubMed1985

Immunological control of drug absorption from the gastrointestinal tract: effect of local anaphylaxis on the intestinal absorption of low molecular weight drugs in the rat.

Intestinal absorption of various drugs was examined by means of in situ recirculation technique during local anaphylaxis. The antibody was determined by passive cutaneous anaphylaxis technique in rats immunized once or three times. The optimal condition of local anaphylaxis was determined by the leakage of Evans Blue. The most significant increase in leaks of the dye was observed by the intraluminal challenge with 400 mg of ovalbumin for 10 min in ovalbumin-immunized rats, and this condition was chosen as the optimal condition of local anaphylaxis. Under this condition, intestinal absorption of caffeine, phenylbutazone, and bromthymol blue (BTB) significantly decreased in ovalbumin-immunized rats compared with the control, whereas no significant effect was noted in the intestinal absorption of salicylic acid, quinine, pralidoxime iodide (2-PAM), tetracycline, and phenol red. In normal rats, no significant decrease was obtained in the intestinal absorption of caffeine, phenylbutazone, and BTB. On the other hand, the decreased absorption of BTB was not found in ovalbumin-immunized rats by the intraluminal challenge with bovine gamma-globulin. Furthermore, there was no significant change in the decreased absorption of BTB between rats immunized once and three times. The most effective condition for decreased BTB absorption was observed by the intraluminal challenge with 200 mg of ovalbumin for 10 min in ovalbumin-immunized rats, which almost correlated with the data of Evans Blue leakage. From these observations, it appears that the mucosal immune responses affect the intestinal absorption of low molecular weight drugs.

Anaphylaxis↗