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Biomedical subjects

K Higaki

Publications and source records attributed to K Higaki.

At least 55 records · Page 3Linked to original sources
PubMed1998

Pharmacokinetics of a novel benzodiazepine partial inverse agonist in the F344 rat, SD rat and B6C3F1 mouse.

1. The pharmacokinetics of a novel benzodiazepine partial inverse agonist (S-8510) were studied in the Fischer 344 (F344) rat and B6C3F1 mouse to obtain information for the planning of carcinogenicity studies. Sprague-Dawley (SD) rats were also included for comparison. 2. Clear non-linear elimination of S-8510 was observed after single oral administration of S-8510 in all animals tested (F344 rat, 1-50 mg/kg; SD rat and B6C3F1 mouse, 1-150 mg/kg). 3. Exposure of S-8510 after single oral administration was in the order F344 rat > B6C3F1 mouse > SD rat. 4. Multiple oral administration to F344 rat and B6C3F1 mouse decreased the exposure to S-8510. 5. These results indicate that it is very important to evaluate pharmacological and toxicological studies based on exposure and to be careful in selecting the species and strains of animal used in toxicology studies.

Administration, Oral↗
PubMed1998

Epidermoid cyst of the spleen with CA19-9 or carcinoembryonic antigen productions: report of three cases.

True splenic cyst is a relatively rare disease, and the majority of the cases are classified as epidermoid cysts. Three cases of epidermoid cysts in the spleen or accessory spleen were studied using an immunohistochemical technique and staining for mucin. In case 1, serum carcinoembryonic antigen (CEA) and CA19-9, and in cases 2 and 3, serum CA19-9, before surgery were markedly elevated, and these levels decreased postoperatively. This strongly indicates the relationship between the increase of tumor marker levels and the presence of the epidermoid cyst. In addition, stratified squamous epithelium in the resected tissues of cases 1 and 2 was positive for anti-CEA antibody and anti-CA19-9 antibody, and that of case 3 was positive for anti-CA19-9 antibody. This strongly supports CEA or CA19-9 production in the squamous epithelium.

Adult↗
PubMed1998

Factors determining drug residence in skin during transdermal absorption: studies on beta-blocking agents.

The factors determining drug residence in skin during penetration across rat abdominal skin were investigated using five beta-blocking agents with different lipophilicities as model drugs in vivo and in vitro. The amount of beta-blocking agent in the skin at steady state correlated well with lipophilicity. The distribution of beta-blocking agents to the stratum corneum and the contribution of intercellular lipids in the stratum corneum to their skin distribution were also correlated with their lipophilicity, suggesting that the stratum corneum, especially intercellular lipids in the stratum corneum, would be responsible for the residence of beta-blocking agents in the skin. Furthermore, cholesterol-3-sulfate, palmitic acid, stearic acid and oleic acid were found to interact with the beta-blocking agents, which are cationized under the physiological condition, and were assumed to play an important role in the skin accumulation. On the other hand, the binding to keratinocyte was so small that keratinocyte might have little effect on the skin accumulation of the beta-blocking agents. Drug transport from the stratum corneum to viable skin was suggested to be regulated by the lipophilicity of these agents. To investigate the residence of these drugs in viable skin, in vitro transport studies using stripped skin were performed. The transport rate constant across viable skin to receptor cells (k23) was inversely correlated with the lipophilicity of the drugs. The elimination rate constants from viable skin (k(vs)) obtained in the in vivo study were much smaller than the values of k23 obtained in the in vitro study, and they were inversely correlated with the binding to cytosol components of viable skin but not the lipophilicity. The viable skin-to-muscle concentration ratio of these drugs, obtained at the beta-phase of the plasma concentration-time curve after intravenous administration, was also inversely correlated with the binding to the cytosol components of viable skin. These results suggest that k(vs) reflects the transport from viable skin to muscle rather than to blood circulation and that the binding of drugs to cytosol components in viable skin would be one of the important factors determining the residence in viable skin.

Administration, Cutaneous↗
PubMed1998

Evaluation of poly(vinyl alcohol)-gel spheres containing chitosan as dosage form to control gastrointestinal transit time of drugs.

Two types of poly(vinyl alcohol)-gel spheres were prepared with chitosan (CS/PVA-GS) and without chitosan (PVA-GS), and comparative studies were performed using these gel spheres (GSs). No change in particle size was observed by the addition of chitosan: nearly 45% of both particles were in the 5-10 microm range. In an in vivo gastrointestinal transit test, CS/PVA-GS prolonged the small-intestinal transit time more than PVA-GS. In an in vitro intestinal perfusion study, the mean transit time of these GSs was markedly reduced by pretreatment of the intestinal surface with a mucolytic agent, N-acetyl-L-cysteine, suggesting that the mucous layer on the intestinal surface plays an important role in controlling the transit rate of these GSs. The oral administration of aminophylline (theophylline) and ampicillin as model drugs incorporated in PVA-GS and CS/PVA-GS was examined in rats. While theophylline absorption from PVA-GS was not affected by the addition of chitosan, the improvement of ampicillin absorption by PVA-GS was enhanced by the chitosan combination.

Administration, Oral↗
PubMed1998

Stereoselective uptake of an organic anion across the renal basolateral membrane in isolated perfused rat kidney.

To clarify which process in renal secretion is responsible for the stereoselective renal secretion of organic anions, the renal handling of enantiomers of 5-monomethylsulfamoyl-6,7-dichloro-2, 3-dihydrobenzofuran-2-carboxylic acid (MBCA) was studied by the multiple-indicator dilution method, using isolated perfused rat kidney. After bolus injection of (R)-(+)-[14C]MBCA or (S)-(-)-[14C]MBCA into the renal artery, the outflow patterns for the perfusate and the urinary excretion rate profiles were estimated by statistical moment analysis. AUC values and mean transit times in kidney for the MBCA enantiomers indicated that (R)-(+)-MBCA was excreted much more extensively in urine and that it had a higher affinity for renal tissue than did (S)-(-)-MBCA. A significantly larger intrinsic clearance of secretion for (R)-(+)-MBCA attested to the R-(+)-preferential renal secretion. The uptake rate constant across the basolateral membrane, the ratio of the uptake rate constant to the free fraction in the perfusate, and the intracellular distribution volume were significantly larger for (R)-(+)-MBCA than for (S)-(-)-MBCA, indicating that uptake across the basolateral membrane and intracellular distribution were R-(+)-preferential. However, the mean time across renal epithelial cells for secreted molecules, the single-pass mean residence time in renal epithelial cells, and the rate constant for secretion across the brush-border membrane were not significantly different between enantiomers. The simultaneous presence of (R)-(+)-MBCA decreased the intrinsic clearance of secretion, the ratio of the uptake rate constant to the free fraction in the perfusate, and the intracellular distribution volume for (S)-(-)-[14C]MBCA, although the secretion rate constant, the mean time across renal epithelial cells for secreted molecules, and the single-pass mean residence time in renal epithelial cells were not influenced by (R)-(+)-MBCA, confirming that uptake across the basolateral membrane and intracellular distribution were stereoselective processes.

Animals↗
PubMed1997

Prediction of the plasma concentration profiles of orally administered drugs in rats on the basis of gastrointestinal transit kinetics and absorbability.

A new method based on gastrointestinal transit kinetics has been developed for estimation of the absorption profiles of drugs administered orally as aqueous solutions. The utility of the method was evaluated in rats. The gastrointestinal transit profile for each segment was estimated by in-vivo studies using phenol red, an unabsorbable marker. The gastrointestinal transit profile of phenol red was well explained by a linear gastrointestinal transit kinetic model with eight segments. We also introduced the absorption process into the gastrointestinal transit kinetic model and the plasma profile was predicted by the convolution method. The absorbability of drugs in each segment was assessed by an in-situ absorption study. The validity of the model was evaluated for model drugs with different absorption characteristics. The plasma profiles predicted for ampicillin, theophylline and cephalexin were in good agreement with those observed. The overestimated plasma profile of propranolol suggests that the low bioavailability of propranolol is a result of first-pass metabolism by the intestine wall and the liver, because the calculated absolute absorption is almost perfect. This proposed model is also suitable for estimation of segmental absorption, which is useful for the development of drug delivery systems. We have demonstrated that the plasma profile of orally administered drugs can be predicted by use of gastrointestinal transit and segmental absorbability information and that this method is especially useful for estimating separately the effect of absolute absorption and first-pass metabolism on the bioavailability of drugs.

Administration, Oral↗
PubMed1997

Developmental changes in pharmacokinetics of recombinant human insulin-like growth factor-I in rats.

Developmental changes in pharmacokinetics of recombinant human insulin-like growth factor-I (rhIGF-I) were investigated after i.v. administration to rats aged 4 and 7 weeks, as young growing rats and adult rats, respectively. rhIGF-I in the plasma declined multi-exponentially in both groups of rats. Plasma concentrations of rhIGF-I were lower at almost all the time points examined in 4 weeks old rats than 7 weeks old rats. The values of total body clearance (CL[total]) and mean residence time (MRT) indicated that rhIGF-I disappeared more rapidly in 4 weeks old rats than 7 weeks old rats at any dosage. Dose-dependent pharmacokinetics was observed in 7 weeks old rats: the higher the dosage was, the larger the value of CL(total) came to be, but not in 4 weeks old rats. The amounts of IGF-binding proteins (IGFBPs) in the plasma were assessed by determining the endogenous IGF-I, and the levels of the 150 kDa complex, a ternary complex of IGF-I with IGFPB-3 and an acid labile-subunit, were found to be lower in 4 weeks old rats than in 7 weeks old rats. In rats at 4 weeks of age, the elimination of rhIGF-I was significantly faster than for the 7 week old rats, which would be due to the lower plasma levels of IGFBP-3 in young growing rats.

Aging↗
PubMed1997

Pharmacokinetics of recombinant human insulin-like growth factor-I in diabetic rats.

Pharmacokinetics of recombinant human insulin-like growth factor-I (rhIGF-I) was investigated after iv administration (0.32, 1.0, and 3. 2 mg/kg) to normal and streptozotocin-induced diabetic rats. rhIGF-I was eliminated from plasma biexponentially in both normal and diabetic rats. Plasma concentrations of rhIGF-I were lower at almost all the time points examined in diabetic rats than in normal rats. The pharmacokinetic parameters of total body clearance (CLtotal), mean residence time (MRT), and elimination rate constant (kel) indicated that rhIGF-I disappeared more rapidly in diabetic rats than in normal rats at any dosage. The amounts of IGF binding proteins (IGFBPs) in plasma were assessed by determining the endogenous IGF-I and. Levels of the 150 kDa complex, a ternary complex of IGF-I with IGFPB-3 and an acid-labile subunit, the 50 kDa complex, a complex of IGF-I with IGFBP-2, were found to be lower in diabetic rats than in normal rats. Fractions of rhIGF-I free and bound to the binding proteins were estimated by gel chromatographic separation of rhIGF-I in plasma after iv administration, and the pharmacokinetics of free and bound rhIGF-I was analyzed independently. Plasma concentrations of free and bound rhIGF-I were lower in diabetic rats than in normal rats, especially the concentrations of the 150 kDa complex were much lower. The reduced IGFBP-3 would be responsible for the faster elimination of rhIGF-I in diabetic rats.

Animals↗
PubMed1997

Gastrointestinal absorption of recombinant human insulin-like growth factor-I in rats.

The GI absorption of recombinant human insulin-like growth factor-I (rhIGF-I) and its improvement were investigated in rats. The 125I-rhIGF-I rapidly degraded to the trichloroacetic acid-soluble form in the small-intestinal contents, but it was relatively stable in the gastric and large-intestinal contents and in the subcellular fraction of the small-intestinal mucosa. To protect rhIGF-I from degradation in the small-intestinal contents, the effect of some adjuvants was examined and their degradation was markedly inhibited by the presence of aprotinin or casein. After p.o. administration of 125I-rhIGF-I at the dose of 1.0 mg/kg, trichloroacetic acid-precipitable radioactivity in the plasma was periodically determined. We found that a considerable amount of rhIGF-I was absorbed into the systemic circulation and that the bioavailability was 9.3%, which is much greater than that of insulin. The coadministration of aprotinin and that of casein enhanced the bioavailability further: 46.9% and 67.0%, respectively. Radioimmunoassay using a monoclonal antibody for rhIGF-I confirmed the high bioavailability of immunoreactive rhIGF-I. From gel chromatography of plasma, the radioactivity in the plasma was found to be in the form of high-molecular-weight complexes. The mechanism for the uptake of rhIGF-I by intestinal mucosa may be absorptive-mediated endocytosis.

Animals↗
PubMed1996

A human combined hepatocellular and cholangiocarcinoma cell line (KMCH-2) that shows the features of hepatocellular carcinoma or cholangiocarcinoma under different growth conditions.

BACKGROUND/AIMS: Combined hepatocellular and cholangiocarcinoma is a rare tumor of the liver, and its histogenesis remains unclear. The authors addressed this issue in the current article. METHODS: A specimen aseptically obtained from the surgically resected combined hepatocellular and cholangiocarcinoma was processed for primary culture. The morphologic features of the established cell line cultured on a plastic dish and in type I collagen gel matrix, and transplanted in nude mice were examined. RESULTS: The authors established a new human combined hepatocellular and cholangiocarcinoma cell line, designated KMCH-2, from a 40-year-old Japanese man. KMCH-2 cells on a plastic dish proliferated in a monolayered sheet with a population doubling time of 32 to 44 h. KMCH-2 expressed functional characteristics of hepatocellular carcinoma, such as albumin synthesis at protein and mRNA levels, but were poorly differentiated in morphology, showing an overlap of features with cholangiocarcinoma. KMCH-2 cells cultured within type I collagen gel matrix proliferated, forming compact to vaguely trabecular and pseudoglandular arrangements, and differentiated to show morphological characteristics of hepatocellular carcinoma unlike the cells on a plastic dish. Mucin production was not detected in KMCH-2 cells in vitro. Subcutaneous tumors which developed in nude mice injected with KMCH-2 cells represented features of adenocarcinoma with mucin production. CONCLUSIONS: The present results revealed the presence of an albumin-producing human hepatic neoplastic cell, such as KMCH-2, that can differentiate to show not only the features of hepatocellular carcinoma but also those of cholangiocarcinoma under certain growth conditions.

Adult↗
PubMed1996

Expression of Fas and anti-Fas-mediated apoptosis in human hepatocellular carcinoma cell lines.

BACKGROUND/AIMS: Fas transduces apoptotic signals upon cross-linking with the Fas ligand, which is experimentally replaced by anti-Fas antibodies. Because little is known about Fas expression and function in hepatocellular carcinoma, these issues are addressed in the current article. METHODS: We examined Fas expressions at protein and mRNA levels, and susceptibility to anti-Fas-mediated apoptosis, on six hepatocellular carcinoma cell lines. RESULTS: Two cell lines constitutively expressed high levels of Fas both on their cell surface and in their cytoplasm, whereas the other four cell lines expressed Fas mainly in their cytoplasm. Fas mRNA of normal size was detected in all cell lines in reverse transcriptase-polymerase chain reaction analyses. Although a Fas mRNA variant, suggesting a soluble Fas molecule, was detected in the two cell lines expressing high levels of Fas, its amount was very small compared to that of normal-sized Fas transcript. Anti-Fas dose-dependently induced apoptosis exclusively in the two cell lines which constitutively express high levels of cell surface Fas. However, after preincubation with interferon-gamma, one cell line with low surface Fas expression became anti-Fas sensitive equivalent to the two cell lines expressing surface Fas at high levels. Studies of two clonally related cell lines showed that dedifferentiated clones had lower Fas expression and resistance to anti-Fas, suggesting deterioration of Fas system after clonal cell dedifferentiation. CONCLUSIONS: These findings suggest sensitivity to anti-Fas is virtually relevant to cell surface Fas, but not to cytoplasmic Fas expression. However, its expression level does not correlate to sensitivity to anti-Fas.

Antineoplastic Agents↗
PubMed1996

Fas antigen expression and its relationship with apoptosis in human hepatocellular carcinoma and noncancerous tissues.

Apoptosis, a programmed cell death, can be observed in the tissues of viral or autoimmune hepatitis and of hepatocellular carcinoma. Fas antigen (Fas) was proposed as a protein that triggers apoptosis. To elucidate the relationship between Fas expression and its location in hepatocellular carcinoma cells, we histochemically examined Fas expression by using 25 hepatocellular carcinoma tissues and their corresponding noncancerous tissues, which were surgically obtained from the same patients. In addition, the relationship between Fas expression and apoptotic cell numbers was examined in the hematoxylin-and-eosin-stained specimens obtained from 23 of the 25 patients. Hepatocellular carcinoma tissues expressed Fas less frequently and more weakly than noncancerous tissues. The majority of noncancerous specimens expressed Fas both on the surface and in the cytoplasm, whereas the majority of hepatocellular carcinoma expressed Fas only in the cytoplasm. Apoptotic cell counts were significantly higher in Fas-expressing tissues than in Fas-negative tissues. Among Fas-expressing tissues, the counts were higher in surface Fas-expressing tissues than in tissues that expressed only cytoplasmic Fas (P < 0.01 to 0.05). Our findings indicate that the development of apoptosis in hepatocellular carcinoma tissues relates to not only Fas expression but also its location.

Adult↗
PubMed1995

Cell-cycle dependent biosynthesis and localization of p53 protein in untransformed human cells.

Localization of p53 in human cultured lymphocytes and in cultured skin fibroblasts was studied by immuno-fluorescent microscopy and post-embedded immunoelectron microscopy using Lowicryl K4M. In quiescent lymphocytes, p53 was found in small amounts in both the cytoplasm and the nucleus. p53 in the nucleus was found associated with the non-chromatin structure. At 24 h or 72 h of PHA stimulation, p53 increased markedly just beneath the plasma membrane and in the nucleus, which stained diffusely with anti-p53. In resting fibroblasts, small amounts of p53 were present in both the cytoplasm and the nucleus. After 16 h of stimulation of confluent-resting fibroblasts by trypsinization and replating, a phase just prior to the initiation of DNA synthesis, p53 slightly increased in both the cytoplasm and the nucleus. Afterwards, p53 was present predominantly in the cytoplasm, closely associated with the cytoskeletal actin filaments. In mitotic cells, p53 was distributed throughout the cytoplasm. When fibroblasts were extracted with saponin, p53 was still associated with the actin filaments, as well as mitochondrial membranes and granular structures of the nuclear matrix. Our data suggest that the initial increase of p53 in cells that enter the cell cycle through G1 first bind to the actin cytoskeleton, and that some of the p53 then move into the nucleus to initiate gene activation and DNA synthesis for cell proliferation. This implies that there is some functionally significant interaction between p53 and actin in the cells.

Cell Cycle↗
PubMed1995

Mortality and morbidity rates, postoperative course, quality of life, and prognosis after extended radical lymphadenectomy for esophageal cancer. Comparison of three-field lymphadenectomy with two-field lymphadenectomy.

PURPOSE: The authors evaluated the efficacy of extended radical (three-field) lymphadenectomy for esophageal cancer compared with less radical (two-field) lymphadenectomy. STUDY SUBJECTS AND ANALYTIC METHODS: The mortality and morbidity rates, postoperative courses, and survival rates were compared between 63 patients who underwent three-field lymph node dissection and 65 who underwent two-field lymph node dissection at Kurume University Hospital from 1986 to 1991. Long-term quality of life after surgery was compared between 37 patients who underwent three-field dissection and 35 who underwent two-field dissection from 1980 to 1991. RESULTS: Three-field dissection resulted in better survival for patients with positive lymph node metastasis from a carcinoma in the upper thoracic or midthoracic esophagus compared with two-field dissection. The mortality rates, postoperative courses and quality of life were the same for both procedures. CONCLUSIONS: Three-field dissection is preferred for upper thoracic or midthoracic esophageal cancer because of improved survival, acceptable mortality and morbidity rates, and good postoperative course and quality of life.

Aged↗
PubMed1995

Expression of intercellular adhesion molecule 1 in human hepatocellular carcinoma.

We investigated the expression of intercellular adhesion molecule 1 (ICAM-1) in ex vivo human hepatocellular carcinoma (HCC) cells and in vitro in eight liver cancer cell lines, including six HCC cell lines and two combined hepatocholangiocarcinoma (CHC) cell lines. Immunohistochemistry showed the expression of ICAM-1 on the HCC cell surface with honeycomblike appearance in most cases (96.2%). On the other hand, hepatocytes in noncancerous areas did not express ICAM-1, except those hepatocytes in the periportal and intra-acinar areas with inflammation. Immunohistochemical study on cultured cells revealed that four cultured HCC cell lines and one CHC cell line constitutively expressed ICAM-1 on the cell surface and in the cytoplasm. Flow cytometric analysis revealed that immunostain-positive cells expressed surface ICAM-1 with more than a 90% positive cell rate, and their expressions were upregulated by incubation of cells with inflammatory cytokines, such as interferon alfa, interferon gamma, tumor necrosis factor-alpha, and interleukin 1 beta. Soluble ICAM-1 was detected in supernatants of cell lines expressing cell surface ICAM-1 expression, and was increased in amounts 2- to 20-fold by inflammatory cytokines. These findings suggest that liver cancer cells in ex vivo may express not only surface but also a soluble form of ICAM-1, differently from normal hepatocytes, and that both expressions are upregulated by inflammatory cytokines.

Blotting, Western↗
PubMed1995

[Clinical investigation of severe pulmonary tuberculosis and miliary tuberculosis].

Although the incidence of pulmonary tuberculosis had been rapidly decreased in Japan, it is pointed out that the rate of decrease in annual incidence became smaller in recent years. This slowing down of the rate of decrease is considered to be resulted from an increase in number of individuals who are more susceptible to tuberculous infection; such as the elderly, young people who are not exposed to TB bacilli previously and therefore not immunized, patients with malignant disease or with organ transplantation and HIV-infected persons. Pulmonary tuberculosis still remained as a pulmonary infectious disease of highly ranked importance. Especially, miliary tuberculosis is life-threatening and occasionally fatal unless early intensive antituberculosis chemotherapy was started on the basis of a rapid and definite diagnosis. We made a retrospective survey to clarify the characteristic clinical features of miliary tuberculosis. For this purpose, we compared the characteristics and clinical features of 10 patients with miliary tuberculosis and those of 18 patients with severe pulmonary tuberculosis, not due to hematogenous dissemination. The mean ages of miliary tuberculosis group and that of severe pulmonary tuberculosis group were 62.6 and 63.8 years old, respectively, with no significant difference. Nine out of ten patients with miliary tuberculosis had fever as one of initial symptoms, whereas, all the patients with severe pulmonary tuberculosis had cough and sputa but they seldom developed fever (high fever) at the initial stage of their diseases. Duration from onset of symptom to the admission was 1.2 months on average in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Ocular absorption, distribution, and systemic absorption of a novel antiglaucoma medication, prostaglandin derivative, in male white rabbits.

A prostaglandin derivative, (5Z,9 alpha,11 alpha,13E)-9,11-dihydroxyprosta- 5,13-dienoic acid sodium salt (S-1033), that lowers intraocular pressure with little adverse effect, may have clinical value in the treatment of glaucoma. After [14C]S-1033 (0.2% solution) was instilled into the eye of a white rabbit, radioactivity and S-1033 appeared in systemic plasma so rapidly (tmax, 5 min) and S-1033 was eliminated very rapidly with half-lives of 2.8 and 11.0 min at alpha- and beta-phases, respectively. The metabolite, M-1, [1R-[1 alpha,2 beta-(1E),3 alpha,5 alpha]]-3,5-dihydroxy-2-(1- octenyl)-cyclopentanepropanoic acid (tetranor-S-1033), appeared in plasma very rapidly (tmax, 5 min), suggesting that a fast metabolism was a major factor in the rapid elimination of S-1033 from plasma. The values for the ratios of the area under the curve of ocular instillation to intravenous administration for radioactivity and S-1033 were 1.01 and 0.52, respectively, indicating that more than half of the S-1033 instilled was transported into the systemic circulation. To clarify the contributing pathway of the massive and rapid systemic absorption of S-1033 after topical dosing, plasma levels of S-1033 were investigated after instillation to rabbits in which the nasolacrimal ducts were occluded. Plasma concentrations of S-1033 were slightly higher than those in intact rabbits, suggesting that conjunctiva would be as important as nasal mucosae for the systemic absorption under the physiological condition. As for the intraocular distribution, the highest levels of radioactivity were found in the cornea, conjunctiva, and anterior sclera.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗