Biomedical subjects

S Kawakami

Publications and source records attributed to S Kawakami.

At least 73 records · Page 4Linked to original sources

PubMed2000

Central bombesin inhibits food intake and the orexigenic effect of neuropeptide Y in the neonatal chick.

It is well known that central injection of bombesin (BN) suppresses feeding in mammalian and avian species, but the anorexigenic effect of central BN are still open with special reference to the chick. The dose response (0, 0.1 and 0.5 microg) of intracerebroventricular (ICV) injection of BN was examined in Experiment 1. ICV injection of BN inhibited food intake in a dose-dependent manner. Experiment 2 was done to determine whether BN interacts with the orexigenic effect of neuropeptide Y (NPY) in the neonatal chick. Central administration of NPY (2.5 microg) greatly enhanced food intake, but co-injection of BN (0.5 microg) suppressed food intake. The dose response of NPY (2.5 microg) co-injected with three levels of BN (0, 0.1 and 0.5 microg) was examined in Experiment 3. ICV injection of BN attenuated the hyperphagia by NPY in a dose-related fashion. It is suggested that central BN may interact with NPY for the regulation of feeding in the neonatal chick.

Animals↗

PubMed2000

Central administration of alpha-melanocyte stimulating hormone inhibits fasting- and neuropeptide Y-induced feeding in neonatal chicks.

In the present study, the effect of intracerebroventricular (i.c.v.) administration of alpha-melanocyte stimulating hormone (alpha-MSH) on food intake of neonatal chicks was examined. In experiment 1, i.c. v. injection of alpha-MSH (0.04, 0.2 and 1 microg) significantly inhibited food intake of 3-h fasted chicks in a dose-dependent manner. In experiment 2, alpha-MSH strongly inhibited neuropeptide Y-induced feeding when neuropeptide Y (2.5 microg) and several doses of alpha-MSH were given simultaneously i.c.v. These results suggest that alpha-MSH plays an important role in the regulation of food intake of neonatal chicks.

Animals↗

PubMed2000

The hepatic vagal reception of intraportal GLP-1 is via receptor different from the pancreatic GLP-1 receptor.

Glucagon-like peptide-1 (7-36)amide (tGLP-1), a representative humoral incretin, released into the portal circulation in response to a meal ingestion, exerts insulinotropic action through binding to the tGLP-1 receptor known to be a single molecular form thus far. We previously reported that the hepatic vagal nerve is receptive to intraportal tGLP-1, but not to non-insulinotropic full-length GLP-1-(1-37), through a mechanism mediated by specific receptor to the hormone. In the present study, we aimed to examine how modification of the receptor function alters this neural reception of tGLP-1, by using the specific agonist, exendin-4, and the specific antagonist, exendin (9-39)amide, of the receptor at doses known to exert their effects on the insulinotropic action of tGLP-1. Intraportal injection of 0.2 or 4.0 pmol tGLP-1, a periphysiological and pharmacological dose, respectively, facilitated significantly the afferent impulse discharge rate of the hepatic vagus in anesthetized rats, as reported previously. However, unexpectedly, intraportal injection of exendin-4 at a dose of 0.2 or 4.0 pmol, or of even 40.0 pmol, did not facilitate the afferents at all. Moreover, intraportal injection of exendin (9-39)amide at 100 times or more molar dose to that of tGLP-1, either 5 min before or 10 min after injection of 0.2 or 4.0 pmol tGLP-1, failed to modify the tGLP-1-induced facilitation of the afferents. The present results suggest that the neural reception of tGLP-1 involves a receptor mechanism distinct from that in the well-known humoral insulinotropic action.

Animals↗

PubMed2000

Glial and neuronal localization of ionotropic glutamate receptor subunit-immunoreactivities in the median eminence of female rats: GluR2/3 and GluR6/7 colocalize with vimentin, not with glial fibrillary acidic protein (GFAP).

Female rat median eminence was immunostained with anti-NR1, GluR1, GluR2/3, GluR6/7, or KA2. GluR2/3- and GluR6/7-immunoreactivities were detected in cells lining the basal portion of the third ventricle. To identify these cells as tanycytes, the median eminence was dual-immunostained with glutamate receptors and glial cytoskeletal marker proteins, such as vimentin or glial fibrillary acidic protein (GFAP). Both GluR2/3 and GluR6/7 were shown to colocalize with vimentin, not with GFAP. These results suggest the potential role for tanycytes in conducting glutamate signaling.

Animals↗

PubMed2000

Brain-derived mast cells could mediate histamine-induced inhibition of food intake in neonatal chicks.

In the present study, the effect of intracerebroventricular (i.c.v.) administration of histamine on food intake of neonatal chicks was examined over 2 h. Histamine (100, 200 or 400 nmol, respectively) was injected in the lateral ventricle of 2-day-old chicks, and cumulative food intakes were measured. i.c.v. injection of histamine significantly inhibited food intake in a dose-dependent manner. In addition, compound 48/80, which causes degranulation of mast cells and release of histamine, or thioperamide, which is an antagonist of the histamine H3 autoreceptor and increases histamine release from histaminergic nerve terminals, was injected i.c.v. to clarify whether mast cell- or neuron-derived histamine in the central nervous system of chicks is essential to the feeding inhibition. Central administration of compound 48/80 inhibited food intake with a dose-dependent manner, but thioperamide had no effect on feeding. An inhibitor of mast cell degranulation, sodium cromoglycate, somewhat attenuated food intake inhibited by compound 48/80. These results suggest that brain-derived mast cells could be a major source of histamine in the inhibition of food intake of neonatal chicks.

Animals↗

PubMed2000

Fucogalactan isolated from Sarcodon aspratus elicits release of tumor necrosis factor-alpha and nitric oxide from murine macrophages.

Eight species of mushrooms were evaluated for mitogenic activity by the tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method using spleen cells of C3H/HeN female mice. The hot water-soluble (HWS) fraction extracted from Sarcodon aspratus showed the highest activity. The mitogen in Sa. aspratus was isolated by Sepharose 6B and DEAE-Sepharose CL-6B column chromatography. Preliminary structural analyses indicated that the mitogen was a fucogalactan. Fucogalactan elicited the release of tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) in macrophages of mice in vitro. TNF-alpha production induced with 50 microg/ml of fucogalactan was significantly higher than that induced by lentinan (500 microg/ml) by approximately 4.3-fold. Also, fucogalactan showed dose dependence at concentrations from 5 to 500 microg/ml in NO production. Thus, fucogalactan does elicit the release of cytokines such as TNF-alpha and NO.

Adjuvants, Immunologic↗

PubMed2000

Effect of viscous additives on drug absorption from the liver surface in rats using phenol red as a model.

The purpose of this study is to obtain information that can be used to improve controlled release and residence time of drugs on the liver surface. Using carboxymethylcellulose sodium salt (CMC-Na) and polyvinyl alcohol (PVA), we examined the effect of viscous formulations on the absorption of phenol red as a model. In the presence of 3% CMC-Na or 15% PVA, the maximum plasma concentration of phenol red decreased after application to the rat liver surface using a cylindrical glass cell. The absorption ratios in 6 h calculated from the remaining amount of phenol red in the glass cell were 68.6, 60.5 and 48.7% (control: 73.1%) in the presence of 1 or 3% CMC-Na and 15% PVA, respectively. As a result of the reduction in the absorption ratio, the amount of phenol red excreted into the bile and urine in 6 h was decreased by the addition of the viscous additives. The decrease in absorption rate was characterized by a pharmacokinetic analysis of the plasma concentration profile. The change in absorption rate differed between the viscous additives, reflecting the result of the in vitro release experiment. Accordingly, the possibility that the drug absorption rate from the liver surface can be altered by viscous additives was suggested to have a promising prospect for therapeutic use.

Absorption↗

PubMed2000

Comparison of antioxidant enzyme activities between Solanum tuberosum L. Cultivars Danshaku and Kitaakari during low-temperature storage.

We compared the antioxidant enzyme activities between Solanum tuberosum L. cultivars Kitaakari and "Danshaku" during storage at 1 degrees C and 20 degrees C. The Kitaakari and Danshaku plants contained approximately 330 microM and 120 microM ascorbic acid (AsA) immediately after the harvest, respectively. At 1 degrees C, the activity of ascorbate peroxidase (APx) in the Kitaakari plants showed the tendency to increase, while in the Danshaku its activity increased temporally by 9 weeks and thereafter returned to basal levels. Superoxide dismutase (SOD) activity increased after 12 weeks in the case of the Kitaakari at 1 degrees C. Catalase did not show any difference in both cultivars at each temperature. The contents of AsA, which was one of the substrates of APx, decreased more rapidly at 1 degrees C than at 20 degrees C in both cultivars. Particularly in the case of the Danshaku, AsA contents were already less than 30 microM at 9 weeks, which confirmed that APx was inactivated.

Ascorbate Peroxidases↗

PubMed2000

In vivo gene delivery to the liver using novel galactosylated cationic liposomes.

PURPOSE: The purpose of this study is to elucidate the in vivo gene transfer for galactosylated liposomes containing cholesten-5-yloxy-N-(4-((1-imino-2-beta-D-thiogalactosyle thyl)amino)butyl)formamide(Gal-C4-Chol) in relation to lipid composition and charge ratio. METHODS: Galactosylated cationic liposomes containing N-[1-(2,3-dioleyloxy)propyl]-n,n,n-trimethylammonium chloride(DOTMA), Gal-C4-Chol and cholesterol(Chol), and similar liposomes were prepared. Plasmid DNA complexed with a galactosylated liposome preparation was injected intraportally into mice. The mice were sacrificed after 6 hours. The tissues were subjected to luciferase assay. RESULTS: A markedly higher gene expression in the liver following injection of plasmid DNA that has been complexed with DOTMA/ Chol/Gal-C4-Chol(1:0.5:0.5) and DOTMA/Gal-C4-Chol(1:1) liposomes was observed. The effect was one order of magnitude higher than naked DNA and DOTMA/Chol(1:1) liposomes. Pre-exposing with galactosylated bovine serum albumin significantly reduced the hepatic gene expression. By comparison, the gene expression for galactosylated cationic liposomes containing 3beta[N-(N',N'-dimethylaminoethane)carbamoyl]cholesterol, Gal-C4-Chol and dioleoylphosphatidylethanolamine was 10 times lower. As far as the charge ratio of DOTMA/ Chol/Gal-CA-Chol(1:0.5:0.5) liposomes to plasmid DNA(1.6-7.0) was concerned, complexes with charge ratios of 2.3-3.1 produced maximal gene expression in the liver. Whereas, higher ratios resulted in enhanced expression in the lung. CONCLUSIONS: By optimizing lipid composition and charge ratio, galactosylated liposome/DNA complexes allow superior in vivo gene transfection in the liver via asialoglycoprotein receptor-mediated endocytosis.

Animals↗

PubMed2000

Mannose receptor-mediated gene transfer into macrophages using novel mannosylated cationic liposomes.

A novel mannosylated cholesterol derivative, cholesten-5-yloxy-N-(4-((1-imino-2-beta-D-thiomannosyl -ethyl)amino)bu tyl) formamide (Man-C4-Chol), was synthesized in order to perform mannose receptor-mediated gene transfer with liposomes. Plasmid DNA encoding luciferase gene (pCMV-Luc) complexed with liposomes, consisting of a 6:4 mixture of Man-C4-Chol and dioleoylphosphatidylethanolamine (DOPE), showed higher transfection activity than that complexed with 3beta[N-(N', N'-dimethylaminoethane)-carbamoyl]cholesterol (DC-Chol)/DOPE(6:4) and N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTMA)/DOPE(1:1) liposomes in mouse peritoneal macrophages. The presence of 20 mM mannose significantly inhibited the transfection efficiency of pCMV-Luc complexed with Man-C4-Chol/DC- Chol/DOPE(3:3:4) and Man-C4-Chol/DOPE(6:4) liposomes. High gene expression of pCMV-Luc was observed in the liver after intravenously injecting mice with Man-C4-Chol/DOPE(6:4) liposomes, whereas DC-Chol/DOPE(6:4) liposomes only showed marked expression in the lung. The gene expression with Man-C4-Chol/DOPE(6:4) liposome/ DNA complexes in the liver was observed preferentially in the non-parenchymal cells and was significantly reduced by predosing with mannosylated bovine serum albumin. The gene expression in the liver was greater following intraportal injection. These results suggest that plasmid DNA complexed with mannosylated liposomes exhibits high transfection activity due to recognition by mannose receptors both in vitro and in vivo. Gene Therapy (2000) 7, 292-299.

Animals↗

PubMed2000

Rabeprazole, amoxycillin and low- or high-dose clarithromycin for cure of Helicobacter pylori infection.

BACKGROUND: Rabeprazole sodium is a proton pump inhibitor. AIM: To evaluate the efficacy and safety of 1-week triple therapy with rabeprazole, amoxycillin and clarithromycin for the eradication of Helicobacter pylori. METHODS: A total of 100 subjects with H. pylori were randomly divided into two groups of 1-week triple therapy with rabeprazole 10 mg b.d., amoxycillin 750 mg b.d. and either clarithromycin 200 mg b.d. (RAC400, n=50) or clarithromycin 400 mg b. d. (RAC800, n=50). Endoscopic examination with four biopsies (two specimens from the antrum and two from the gastric body) was performed. The status of H. pylori infection was determined using culture and histology (Giemsa stain) of the biopsy specimens. Sensitivity to clarithromycin was determined using the E-test: MIC > 8 g/mL was considered to be resistant, whereas MIC < 2 g/mL was considered to be sensitive. Cure was defined as no evidence of H. pylori infection 1 month after completion of treatment. RESULTS: There were no significant differences in the clinical characteristics of the two groups. Eradication rates (intention-to-treat and per protocol, respectively) were: RAC400: 86% (95% CI: 76-95%) and 89% (95% CI: 80-97%); RAC800: 94% (95% CI: 87-100%) and 97% (95% CI: 94-100%). There was no significant difference between the eradication rates of either regimen. Three subjects with failed eradication in the RAC400 group were all infected with a clarithromycin-resistant strain before beginning the therapy. Haemorrhagic colitis was the only severe adverse event, which was observed in one patient in the RAC800 group. CONCLUSION: One-week triple therapy with rabeprazole, amoxycillin and low-dose clarithromycin is effective for the eradication of H. pylori infection.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2000

Retrospective analysis of type of hepatic resection for hepatocellular carcinoma.

BACKGROUND: Hepatic resection for hepatocellular carcinoma is now considered a relatively safe procedure, owing to refined surgical techniques and management. METHODS: Three hundred different types of hepatic resection performed in one hospital were reviewed retrospectively. The operative morbidity and mortality rates and long-term survival were assessed. RESULTS: Tumours were extirpated by lobectomy or extended lobectomy in 48 patients, by segmentectomy in 53, by subsegmentectomy in 94 and by partial resection in 105. The overall hospital mortality rate was 4 per cent (13 of 300). No operative death occurred after lobectomy or extended lobectomy. Segmentectomy and subsegmentectomy were associated with high postoperative complication and hospital mortality rates. There was a significant difference in survival rate between patients with and without a cancer-free surgical margin of more than 1.0 cm. The overall 5- and 9-year survival rates were 51 and 9 per cent respectively. Rates were 56 and 24 per cent for lobectomy or extended lobectomy. CONCLUSION: For tumours of 2.1 cm or more in size lobectomy appears to carry the least risk of postoperative complications and death in hospital and best achieves a cancer-free surgical margin.

Carcinoma, Hepatocellular↗

PubMed2000

Differentiated thyroid carcinomas. Prediction of tumor invasion with MR imaging.

PURPOSE: To assess diagnostic accuracy for tumor invasion of surrounding organs by measurement of tumor circumferences on MR images in patients with differentiated thyroid carcinomas. MATERIAL AND METHODS: Surgical and MR imaging findings in 50 patients with differentiated thyroid carcinoma (43 primary, 7 recurrent lesions) were retrospectively reviewed. The degrees of circumference of tumor encroachment to the organs were measured, and the measurements and morphologic diagnosis of tumor invasion made by a head and neck radiologist were compared with surgical and pathologic findings using receiver operating characteristic curves. RESULTS: Diagnosis of tumor invasion by the radiologist was superior to the measurements of the carotid artery and cartilage, while the reverse was true for the trachea and esophagus. However, no statistical differences were noted between them for each structure. Optimal thresholds for tumor invasion were 90 degrees or more for the cartilage (94% accuracy) and esophagus (86% accuracy), 135 degrees or more for the trachea (86% accuracy), and 225 degrees or more for the carotid artery (90% accuracy). CONCLUSION: Tumor invasion was more accurately diagnosed by measurement of tumor circumferences of each organ on MR images.

Adenocarcinoma, Follicular↗

PubMed2000

Preoperative concurrent chemoradiotherapy against muscle-invasive bladder cancer: results of partial cystectomy in elderly or high-risk patients.

BACKGROUND: Good local control has been reported in cases of muscle-invasive bladder cancer treated by chemoradiotherapy and transurethral resection (TUR). However, definitive irradiation or extensive chemotherapy is often intolerable for elderly or poor-risk patients. We report here benefits of partial cystectomy after concurrent low-dose chemoradiotherapy for high-risk patients. METHODS: Thirty-seven patients with localized muscle-invasive bladder cancer (T2-T4) were treated with concurrent cisplatin (50-100 mg/body x 2 courses) and pelvic irradiation (40 Gy) preoperatively. Among 17 patients (46%) who achieved complete response (CR), 10 were not suitable for radical cystectomy and underwent partial cystectomy. Radical cystectomy was performed in 24 cases [CR = 6, partial response (PR) = 18]. Two patients (one CR and one PR) rejected open surgery and were treated by TUR of the primary site. One no change (NC) patient received no further treatment because of mental disorder. RESULTS: Median follow-up was 12 months (range 2-37 months). Fifteen of 36 evaluable cases (42%) achieved a pathological T0 response (no residual tumor). Estimated 3-year disease-free survival was 56% for all patients and 100% for T0 responders. Seven of 21 patients with pathological persistent tumor developed local recurrence (three patients) or distant metastasis (four patients). All of the 10 patients (eight with T0 response and two with a small residual tumor nest) who underwent partial cystectomy were recurrence-free for an observation period of up to 3 years. CONCLUSIONS: Bladder preservation by partial cystectomy may be a choice for patients who show a good response to preoperative chemoradiotherapy and are not suitable for radical cystectomy.

Aged↗

PubMed2000

Head and neck lesions: determination of an optimal MT technique for prediction of malignancies.

RATIONALE AND OBJECTIVES: To determine an optimal magnetization transfer (MT) technique for diagnosis of malignancies in the head and neck. METHODS: Lesion magnetization transfer ratios (MTRs) and lesion-to-muscle MTRs were prospectively measured in 52 head and neck lesions of 52 patients at frequency offsets of 0.3, 0.5, and 1 kHz from water resonance. The diagnostic capability for each MT pulse was calculated by using receiver operating characteristic (ROC) curves, and an optimal MT technique was determined for diagnosis of malignancies. RESULTS: The lesion MTRs and the lesion-to-muscle MTRs in malignant tumors were statistically significantly greater than those in benign lesions at both 0.5- and 1-kHz MT pulses, but no significant differences were noted between them at the 0.3-kHz MT pulse. Diagnosis with the lesion-to-muscle MTRs was better than that with the lesion MTRs at each MT pulse. Among all MTRs, lesion-to-muscle MTRs at the 1-kHz MT pulse showed the highest diagnostic capability for malignancies (area under the ROC curve = 0.82+/-0.06). With a lesion-to-muscle MTR at a 1-kHz MT pulse of 0.61 or greater, the highest accuracy of 85% was attained with 90% sensitivity and 77% specificity. CONCLUSIONS: Lesion-to-muscle MTRs at a 1-kHz MT pulse were optimal for diagnosis of malignancies in the head and neck.

False Positive Reactions↗

PubMed2000

Bleaching effect of sodium percarbonate on discolored pulpless teeth in vitro.

The purpose of this study was to evaluate the bleaching effect of sodium percarbonate on artificially stained pulpless teeth. Twenty extracted human mandibular premolars were stained by immersing them in human blood mixed with iron sulfide, and divided into three test groups and one control group. The following bleaching agents were used: sodium perborate mixed with 30% hydrogen peroxide (WB), sodium percarbonate mixed with distilled water (PW) or 30% hydrogen peroxide (PH). On days 5, 10, and 15, each pulp chamber was refilled with fresh bleaching paste. The L* (average lightness) of the midbuccal area of specimens was measured before and after staining, and on days 5, 10, 15, and 20 by colorimeter. The bleaching effect was evaluated by the lightness recovery rate (LRR) calculated from L*. WB showed the highest LRR among all groups, and PW and PH showed significantly higher LRR when compared with the control group. PW and PH were not significantly different. Results showed that sodium percarbonate had an obvious bleaching effect without hydrogen peroxide and indicated that it could be a safe intracoronal bleaching agent.

Borates↗

PubMed2000

Germ-line mutation analysis in patients with von Hippel-Lindau disease in Japan: an extended study of 77 families.

We have previously reported on the analysis of germ-line mutations in Japanese von Hippel-Lindau disease (VHL) patients and found mutations in 26 families. We have now extended these studies to include an additional 41 VHL families. Germ-line mutation of the VHL gene was screened by DNA-SSCP, direct sequencing, and Southern blot analysis. To summarize all of the data we have studied in this and our previous report, germ-line mutations have been detected in 55 of 77 (73%) (type 1: 41/62 (66%) and type 2: 14/15 (93%)) families. We found similarities in the nature of germ-line mutations including mutational incidence, location, and DNA substitution patterns between Japanese and Western VHL. These similarities may reflect the predominance of endogenous mutational processes. We also found several interesting characteristics in Japanese VHL. Twenty of 41 (49%) intragenic mutations were unique and not reported in the Western VHL. Four mutations (Arg113Stop, Gln132Stop, Leu158Val, and Cys162Tyr) previously characterized as type 1 mutations were identified in the type 2 (with pheochromocytoma) Japanese families. Genotype-phenotype correlation study suggested non-missense mutations predicted to result in the loss of VHL function were associated with the occurrence of renal cell carcinoma, as in sporadic tumors. Our data add to the diversity of VHL germ-line mutations and provide a better understanding of VHL disease in terms of both clinical management and molecular pathogenesis.

Genotype↗

PubMed2000

[Evaluation of a new method for antifungal drugs susceptibility testing to yeasts].

We compared the Etest with a broth microdilution method (FP panel), performed according to the National Committee for modified Clinical Laboratory Standards (NCCLS) document M27-P guidelines, for determining the MICs of 81 clinical isolates of yeasts (7 Candida albicans, 8 Candida glabrata, 10 Candida parapsilosis, 6 Pichia anomala, 10 Candida tropicalis, 4 Candida guilliermondii, 4 Candida krusei, 6 Trichosporon cutaneum, 5 Candida ciferrii, 3 Candida famata, 4 Candida norvegensis, 2 Rhodotorula rubra, 3 Candida lusitaniae, 2 Candida curvata, 1 Candida inconspicua, 1 Candida intermedia, 1 Candida colliculosa, 1 Cryptococcus spp, 1 Tricosporon capitatum, 1 Pichia ohmeri, 1 Saccharomyces cerevisiae). The Etest results for 6 ATCC standard strains correlated well with reference MICs except those of flucytosine (5-FC) for C. krusei, which tended to be 1 to 2 log2 dilution higher than the MIC range determined by NCCLS guidelines. However, the best agreement between the results for clinical isolates was seen with 5-FC (100% agreement [Within +/- 2 log2 dilutions] between the results of the two methods). There was a 91.4% agreement between the results of the two methods with amphotericin B (Etest MICs tended to be 1 to 2 log2 dilution lower than those of the FP panel). The Etest results with litraconazole for clinical isolates except C. tropicalis were similar to MICs of the FP panel (Etest for C. tropicalis showed 1 to 2 log2 dilution lower than FP panel). Also, the Etest results with fluconazole for clinical isolates except C. tropicalis were similar of 1 log2 dilution higher than MICs of the FP panel (Etest for C. tropicalis showed more than 2 log2 dilution lower than FP panel). These results showed a good level of overall agreement between the Etest method and the broth microdilution test (FP panel). Since the Etest is a less laborintensive and much simpler method, it appears to be a useful procedure for testing the susceptibility of yeasts to antifungal agents.

Antifungal Agents↗