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Biomedical subjects

T Takeuchi

Publications and source records attributed to T Takeuchi.

At least 973 records · Page 54Linked to original sources
PubMed1992

Key roles of nitric oxide and cyclic GMP in nonadrenergic and noncholinergic inhibition in rat ileum.

Nonadrenergic and noncholinergic (NANC) inhibitory responses in circular and longitudinal muscles of the rat ileum were studied separately in vitro. Localized distension with a small balloon caused relaxation of the circular muscle on the anal side of the distended region. Nitro-arginine inhibited the relaxation and L-arginine counteracted the effect of nitro-arginine. Treatment of the preparation with superoxide dismutase (SOD) and methylene blue resulted in enhancement and inhibition, respectively, of the relaxation induced by distension. Nitric oxide caused relaxation of the circular muscle in a dose-dependent manner. 8-Bromo cyclic GMP (cGMP) caused relaxation of the circular muscle. Electrical transmural stimulation caused relaxation followed by a rebound contraction of the longitudinal muscle. Nitro-arginine inhibited the relaxation and L-arginine counteracted this inhibition. Similar results to those in the circular muscle were obtained in the longitudinal muscle with SOD, methylene blue, nitric oxide and 8-bromo cGMP. Electrical field stimulation increased the cGMP content of the longitudinal muscle preparation. Nitric oxide also increased the cGMP content of smooth muscle cells obtained from circular and longitudinal muscles of rat ileum. Preincubation of smooth muscle cells with methylene blue inhibited the effect of nitric oxide on the cGMP content. These results suggest a key role of cGMP in NANC inhibitory responses in rat ileum. The factors mediating the responses are discussed.

Animals↗
PubMed1992

High in vitro-in vivo correlation of drug response using sponge-gel-supported three-dimensional histoculture and the MTT end point.

The in vitro sponge-gel-supported three-dimensional histoculture chemosensitivity assay (Hoffman assay) allows the in vivo-like culture of human tumors. In this study, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H tetrazolium bromide (MTT) end point was applied to the Hoffman assay in an attempt to increase in vitro-in vivo correlation. The chemosensitivities of 16 human tumor lines were determined in vitro by the histoculture assay, and retrospectively correlated to their in vivo chemosensitivity as xenografts in nude mice. The in vitro test was considered to be positive if tumor-cell MTT reduction activity was lowered by more than 50%. The cutoff drug concentrations to determine sensitivity in vitro were determined for mitomycin C, doxorubicin, 5-fluorouracil and cisplatin. Using these cutoff drug concentrations in vitro we found, as a function of time of exposure, a strong correlation between serum drug concentrations found in nude mice given maximum tolerated doses and drug concentrations found in the histoculture media in vitro, thereby establishing a relationship between the amounts of drugs to which tumors were exposed in vivo and in vitro. The overall correlation rate of the efficacy results of the drug-response assay to in vivo chemosensitivities was 89.8%, with 90.0% true-positive and 89.7% true-negative rates, 81.7% sensitivity and 94.6% specificity, thereby indicating potential clinical use for tumor histoculture with the MTT end point.

Animals↗
PubMed1992

Biotinylated 1012-S conjugate as a probe ligand for benzodiazepine receptors: characterization of receptor binding sites and receptor assay for benzodiazepine drugs.

A nonisotopic receptor assay using the biotin-1012-S conjugate was developed and the usefulness of this conjugate as a probe ligand for the benzodiazepine receptor was evaluated. The conjugate was incubated in a receptor suspension, and then the concentration of free conjugate in the supernatant was determined nonisotopically with a solid-phase avidin-biotin binding assay. Studies on the ligand saturation with the conjugate demonstrated that the conjugate has very high affinity and specificity for the receptors and the biotin labeling does not decrease the affinity of 1012-S. This assay method was applied to the characterization of binding sites of benzodiazepine receptors in cow brain. Competition interactions between the conjugate and benzodiazepine drugs gave well-defined dose-response curves. These results confirm the possibility that this conjugate could serve as a probe for the study of receptor-ligand interactions and provide the basis of a new nonisotopic receptor assay for benzodiazepine drugs.

Animals↗
PubMed1992

Non-isotopic receptor assay for benzodiazepines using a biotin-labeled ligand and biotin-immobilized microtiter plate.

A non-isotopic receptor assay for benzodiazepine drugs was developed using a biotin-labeled ligand, biotin-1012S. Biotinylated bovine serum albumin (biotin-BSA) was immobilized onto the wall of microtiter plate wells by simple adsorption. Avidin peroxidase conjugate could be extracted from solution owing to its strong interaction with biotin. The amount of avidin peroxidase taken up on the wall was then determined by measuring the enzyme activity. The competition between immobilized biotin on the wall and free biotin for avidin provided the basis for a solid-phase avidin-biotin binding assay. By this binding assay, not only biotin but also biotin-1012S could be measured sensitively. Because 1012S is a ligand with high affinity to benzodiazepine receptors, biotin-1012S could be utilized as a probe ligand for a non-isotopic receptor assay. Based upon the competition between biotin-1012S and various benzodiazepine drugs for the receptor binding sites, a non-isotopic receptor assay was demonstrated.

Animals↗
PubMed1992

Glycosylation-inhibiting factor from human T cell hybridomas constructed from peripheral blood lymphocytes of a bee venom-sensitive allergic patient.

Human T cell hybridomas, which constitutively secrete glycosylation inhibiting factor (GIF), were constructed from PBL of an allergic individual who was sensitive to honey bee venom. PBMC of the patient were stimulated with either denatured or cyanogen bromide-treated bee venom phospholipase A2 (PLA2), and Ag-activated cells were propagated by IL-2 in the presence of human recombinant lipocortin I. T cells obtained in the cultures were fused with a HAT-sensitive mutant of the human lymphoblastoid cell line CEM. Approximately one-third of hybridoma clones constitutively secreted GIF. The GIF-producing hybridomas were CD3+ and bore TCR-alpha beta. GIF formed by unstimulated hybridomas lacked affinity for bee venom PLA2. Upon cross-linking of CD3, however, a majority of the GIF-producing hybridomas formed IgE-binding factors and GIF, the latter of which had affinity for bee venom PLA2. Both nonspecific GIF and Ag-binding GIF from the hybridomas bound to an immunosorbent coupled with the anti-lipomodulin mAb 141-B9. Using an affinity-purified GIF as an immunogen, we established mouse B cell hybridomas that secreted monoclonal anti-human GIF. In order to characterize human nonspecific GIF, one of the GIF-producing hybridomas was adapted to a serum-free medium, and culture supernatant was fractionated by DEAE-Sepharose column chromatography and by gel filtration. The majority of nonspecific GIF in the culture supernatant was recovered from DEAE-Sepharose by elution of the column with 10 mM Tris-HCl buffer, pH 8.0, containing 50 mM NaCl. Affinity-purification of GIF in the DEAE Sepharose fraction by using anti-GIF-coupled Affigel, and analysis of the purified GIF by SDS-PAGE revealed that human GIF is a single polypeptide chain of 14 to 15 kDa. Gel filtration of both crude and affinity-purified GIF preparations confirmed the molecular size of the cytokine.

Antibodies, Monoclonal↗
PubMed1992

Mechanized assay of serum cholinesterase by specific colorimetric detection of released acid.

An automated assay method has been developed for the measurement of serum cholinesterase activity. The samples were prepared by an automated liquid handling unit and incubated for 9.7 min at 30 degrees C, followed by automatic injection into a colorimetric flow injection determination system for acetic acid liberated from acetylcholine by cholinesterase catalytic activity. The coloration reaction employed is based upon the formation of 2-nitrophenylhydrazide utilizing a water-soluble carbodiimide and has a high selectivity for carboxylic acids. The coefficients of variation of the proposed method were 2.4% for within-run analysis (n = 14) and 2.6% for between-run analysis (n = 6). Sera of 55 hospitalized patients were analyzed and the values obtained correlated well with an automated differential pH method (gamma = 0.989).

Acetates↗
PubMed1992

Establishment and characterization of a thymic carcinoma cell line (Ty-82) carrying t(15;19)(q15;p13) chromosome abnormality.

A new human cell line, designated Ty-82, was established from the pleural effusion of a 22-year-old woman with undifferentiated thymic carcinoma. This cell line consisted of primitive cells that were positive for alpha-naphthyl butyrate esterase and acid phosphatase. The cells were shown to express epithelial membrane antigen, but were completely negative for cytokeratin, carcinoembryonic antigen, glial fibrillary acidic protein, desmin, S-100 protein, lysozyme, Leu-7, HLA-DR (Ia), leukocyte common antigen, Ki-I antigen, T-cell antigens, B-cell antigens, myelomonocyte antigens, and Epstein-Barr-virus nuclear antigen. Electron microscopy showed that the cells were highly anaplastic, with no sign of cellular differentiation to any lineages. The Ty-82 cell line was found to have a karyotype of 46,XX,t(15;19)(q15;p13), being identical to that of the patient's tumor cells. Four of 5 nude mice inoculated sub-cutaneously with Ty-82 cells developed tumors which displayed a histological picture similar to the original tumor. Thymic carcinoma is a recently recognized entity, and its cellular and clinical behavior are poorly understood. The newly established thymic carcinoma cell line would provide a useful tool for the better understanding of this rare disease.

Adenocarcinoma↗
PubMed1992

A prolongation of hepatic vascular exclusion by in situ hypothermic perfusion in dogs.

In situ hypothermic hepatic perfusion was performed in dogs to explore whether the time limit of hepatic vascular exclusion could be prolonged. During hepatic vascular exclusion, hepatic hypothermic perfusion was performed via portal vein using various perfusates under active bypass from the portal vein and infrahepatic inferior vena cava area to the superior vena cava system. Dogs receiving hepatic hypothermic perfusion for 1 hour died when given Ringer's solution but survived more than 7 days when given Euro-Collins' and University of Wisconsin solutions. Although dogs tolerated 2 hours of hepatic hypothermic perfusion when give University of Wisconsin solution, all dogs died by 2 hours of hepatic hypothermic perfusion when given Euro-Collins' solution. The hepatic energy charge and arterial ketone body ratio of dogs that died were significantly lower than for those that survived. This suggests that the regimen of hepatic hypothermic perfusion with University of Wisconsin solution is able to maintain the energy metabolism of the liver under hepatic vascular exclusion for prolonged periods, hence, its possible clinical application.

Adenosine↗
PubMed1992

Papaverine inhibits transcytotic vesicle transport and lipid excretion into bile in isolated perfused rat liver.

Papaverine is a nonspecific smooth muscle relaxant and a phosphodiesterase inhibitor. Its effects on biliary excretion of lipids and horseradish peroxidase were investigated in a single-pass isolated perfused rat liver model. A constant infusion of papaverine (1.6 mumol/min; 40 mumol/L) significantly increased bile flow (microliters per minute per gram of liver) before (2.03 +/- 0.09 vs. 1.0 +/- 0.06) and after sodium taurocholate infusion (2.77 +/- 0.10 vs. 1.88 +/- 0.11). However, papaverine significantly and reversibly reduced biliary excretion of phospholipids and cholesterol (nanomoles per minute per gram of liver) after a 1.0 mumol/min sodium taurocholate infusion, from 7.45 +/- 0.83 and 1.42 +/- 0.15 to 1.75 +/- 0.18 and 0.39 +/- 0.06, respectively (p less than 0.01), whereas secretion of bile acids was unaffected. When a 1-min pulse of horseradish peroxidase (25 mg) was infused in isolated perfused rat liver after a continuous infusion of N6,O-2'-dibutyryladenosine 3',5'-cyclic monophosphate (0.25 mumol/min; 6.25 mumol/L), horseradish peroxidase appeared in bile in an early (4 to 6 min) and late (20 to 25 min) peak. Papaverine significantly reduced the late peak, from 1.211 +/- 0.264 to 0.498 +/- 0.107 (p less than 0.01). Papaverine had no significant effects on either cyclic AMP or cyclic GMP in the liver and bile, although it has been reported that papaverine is a phosphodiesterase inhibitor. These findings indicate that papaverine inhibits biliary excretion of lipids but not bile acids, and they suggest that papaverine has an inhibitory effect on transcytotic vesicle transport independent of an increase of cyclic nucleotides in hepatocytes.

Animals↗
PubMed1992

Nucleolar organizer regions in prostate cancer.

A silver colloid technique for the staining of nucleolar organizer regions (NORs) was applied to paraffin sections of 52 clinical prostate cancers, 5 incidental carcinomas of the prostate, 12 benign prostatic hypertrophy (BPH) specimens and 7 normal prostates. The mean numbers of silver-stained NORs (AgNORs) in these lesions were 3.12 +/- 0.52 in clinical cancer, 2.65 +/- 0.64 in incidental cancer, 1.66 +/- 0.16 in BPH, and 1.76 +/- 0.22 in normal prostate. There was a statistically significant difference in agNORs numbers between cancer and benign prostatic tissues (p < 0.001). However, no significant difference was observed in AgNORs numbers between incidental and clinical carcinoma of the prostate. In clinical cancer, only poorly differentiated adenocarcinoma showed a statistically larger number of AgNORs than the well or moderately differentiated group (p < 0.02). Correlation between AgNORs numbers and clinical stage was not obvious. There was no relationship between the number of AgNORs and serum values of tumor markers such as PAP, PSA and gamma-Sm. Moreover, the AgNORs numbers did not show a relation to decreasing rates of serum marker levels during successful anti-androgen therapy. If the patients with prostate cancer were divided into two groups by 2.9 of AgNORs number, the group with the smaller number of AgNORs (n = 14) was found to have a tendency towards a longer disease-stabilizing period than the larger group (n = 17).

Androgen Antagonists↗
PubMed1992

Enhancement of host resistance to opportunistic infections by ubenimex (bestatin).

Ubenimex is a low molecular biological response modifier (BRM) which has been demonstrated to have antitumor and immunomodulatory activities. In this study, the effect of ubenimex on infection with Candida albicans was investigated in normal and immunosuppressed mice, and it showed a prophylactic effect. In normal mice, ubenimex prolonged survival time in a dose-dependent manner. In immunosuppressed mice treated with cyclophosphamide 4 days before infection, ubenimex at 5 mg/kg for 5 days significantly increased the number of survivors. Significant improvement in peritoneal leukocyte counts and in function of neutrophils including phagocytosis and release of activated oxygen was observed in ubenimex-treated mice. These results indicate that ubenimex is a potent BRM for prevention against opportunistic infections.

Animals↗
PubMed1992

Granulovacuolar degeneration in the hippocampal cortex of aging and demented patients--a quantitative study.

The occurrence and topographic analysis of granulovacuolar degeneration (GVD) in the hippocampal cortex of mentally normal controls (75 cases) and patients with Alzheimer's dementia (AD; 17 cases which included Alzheimer's disease and senile dementia of Alzheimer type), multi-infarct dementia (MID; 16 cases), Pick's disease (PD; 5 cases) and atypical dementia [5 cases; non-Alzheimer, non-Pick dementia with Fahr's syndrome (NANPDF)] were investigated. GVD was rarely found in control cases below the age of 60 years. In elderly normal brains, the statistically most representative ranking order of predilection for GVD (in decreasing severity) was: in the 60 s, CA1 > prosubiculum > CA2 (no GVD was found in the CA3 and CA4); in the 70 s, CA1 > prosubiculum > CA2 > CA3 > CA4; in the 80 s, CA1 > prosubiculum > CA2 > CA3 > CA4; in the 90 s, CA1 > prosubiculum > CA2 > CA3 > CA4. In the brains of demented patients, the rank order for GVD was: for AD, CA1 > CA2 > CA3 > prosubiculum > CA4; for MID, CA1 > prosubiculum > CA2 > CA3 > CA4; for PD, CA1 > CA2 > CA3 > prosubiculum > CA4; and for atypical dementia (NANPDF), CA1 > CA2 > prosubiculum > CA3 > CA4. The similarity of the predilection to ranking order was noted both in normal aged subjects and in MID as well as both in AD and in PD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Intra-arterial administration of methotrexate, adriamycin, and cisplatin as neoadjuvant chemotherapy for bladder cancer.

As neoadjuvant chemotherapy for advanced bladder cancer, the intra-arterial administration of methotrexate (MTX), Adriamycin (ADM), and cisplatin (CDDP; IA-MAC) was evaluated. A total of 48 patients with bladder cancer (greater than or equal to T2 or CIS) were selected and received 30.1 mg MTX, 34.5 mg ADM, and 89.1 mg CDDP as an average course. The mean tumor-regression rate after 2 or 3 weeks was 52.3%, and patients with grade 3 transitional-cell carcinoma showed the best results, achieving a 69.6% regression rate. In 30 cases (63%), downstaging was observed. Among the 46 patients who underwent subsequent surgical therapy, the bladder could be preserved in 26 cases by transurethral resection or segmental resection. According to the criteria of the Japanese Association of Cancer Therapy, a histological effect of GIII or better was obtained in 15 cases (29%). The histological effect correlated well with the tumor-regression rate. As compared with intravenous therapy with MTX, vinblastine, ADM, and CDDP (M-VAC), IA-MAC treatment was well tolerated due to its lower degree of bone marrow suppression, and it resulted in a longer disease-free interval and better survival. In addition, the period prior to surgical therapy was shortened in this study. These results suggest that IA-MAC chemotherapy can be useful as an arm of multidisciplinary treatment of advanced bladder tumors.

Aged↗
PubMed1992

Role of endogenous secretin and cholecystokinin in intraduodenal oleic acid-induced inhibition of gastric acid secretion in rats.

We investigated a possible role of endogenous secretin and cholecystokinin (CCK) in inhibition of gastric acid secretion induced by intraduodenal administration of oleic acid in rats. Intraduodenal administration of oleic acid emulsion in a dose of 1 mmol/hr resulted in significant inhibition of gastric acid secretion stimulated by intravenous infusion of pentagastrin (0.3 micrograms/kg/hr), and this was accompanied by an increase in the plasma concentration of both secretin and CCK, from 1.2 +/- 0.08 pM and 20.6 +/- 1.2 pM to 4.3 +/- 0.18 pM and 31.6 +/- 0.9 pM, respectively (P less than 0.001). Intravenous infusion of secretin (0.05 CU/kg/hr) inhibited pentagastrin-stimulated gastric acid secretion, but CCK-8 (0.03 micrograms/kg/hr) failed, although intravenous infusion of secretin and CCK in those doses produced plasma levels comparable to the levels achieved in response to oleic acid administration. Furthermore, the oleic acid-induced suppression of gastric acid secretion was blocked significantly by intravenous injection of rabbit anti-secretin serum (0.1 ml), but not by intravenous infusion of a CCK-receptor antagonist, CR 1409 (5 mg/kg/hr). Thus, the results of this study indicate that endogenous secretin rather than CCK is involved in the hormonal mechanism regulating the inhibition of gastric acid secretion by intestinal fat in rats.

Animals↗
PubMed1992

Differentiation of reptilian neural crest cells in vitro.

An attempt was made to culture neural crest cells of the turtle embryo in vitro. Trunk neural tubes from the St. 9/10 embryos were explanted in culture dishes. The developmental potency of the turtle neural crest cells in vitro was shown to be essentially similar to that of avian neural crest cells, although they seem to be more sensitive to melanocyte-stimulating hormone (MSH) stimulation. We describe conditions under which explanted neural tube gives rise to neural crest cells that differentiate into neuronal cells and melanocytes. The potency of melanocyte differentiation was found to vary according to the concentration of fetal bovine serum (FBS, from 5 to 20%). Melanization of neural crest cells cultured in the medium containing FBS and alpha-MSH was more extensive than those cultured with FBS alone, combinations of FBS and chick embryo extract, or turtle embryo extract. These culture conditions seem to be useful for the study of the developmental potency of the neural crest cells as well as for investigating local environmental factors.

Animals↗
PubMed1992

Mediation of trypsin inhibitor-induced pancreatic hypersecretion by secretin and cholecystokinin in rats.

We investigated a hormonal mechanism in a trypsin inhibitor-induced pancreatic hypersecretion in rats. Intraduodenal administration of a synthetic trypsin inhibitor, camostat, resulted in significant increases in plasma concentration of both secretin and cholecystokinin in a dose-related manner that paralleled a significant increase in exocrine pancreatic secretion. To eliminate the effect of circulating secretin in rats, a rabbit antisecretin serum was given IV that resulted in a 77% reduction in bicarbonate secretion stimulated by intraduodenal camostat. A cholecystokinin receptor antagonist, MK-329, also inhibited significantly the camostat-induced increase in pancreatic secretion; volume and bicarbonate output were reduced by 35% each and amylase output by 73%. The combined administration of antisecretin serum and MK-329 completely abolished the pancreatic exocrine secretion stimulated by camostat. These observations indicate that the camostat-stimulated pancreatic exocrine secretion is mediated by the increased release of both secretin and cholecystokinin in rats.

Analysis of Variance↗