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Biomedical subjects

T Chiba

Publications and source records attributed to T Chiba.

At least 361 records · Page 20Linked to original sources
PubMed1995

Development and preliminary application of high-performance liquid chromatographic assay of urinary metabolites of diazepam in humans.

A simple high-performance liquid chromatographic method for the measurement of diazepam (DZP) and its major metabolites, N-desmethyldiazepam (DMDZP), temazepam (TZP) and oxazepam (OZP) in urine was developed. Preliminary studies of DZP metabolism were also undertaken in four healthy volunteers after administration of a single oral dose (4 mg) of DZP. The assay allowed the simultaneous determination of all analytes in 1 ml of urine and the detection limit was 2 ng/ml with a signal-to-noise ratio of 3. None of 22 drugs and 17 metabolites, except for mianserin, maprotiline and imipramine N-oxide, interfered with the detection of DZP metabolites. Recoveries of the analytes and the internal standard (prazepam) were > 82%. Intra- and inter-assay coefficients of variation for all analytes were < 5.5 and 4.1%, respectively. The mean (+/- S.D.) cumulative urinary excretions of DMDZP, TZP and OZP over 96 h after a single oral administration of DZP were 3.9 +/- 0.4, 6.6 +/- 1.4 and 2.8 +/- 0.6% of the dose, respectively. The urinary excretion of DZP was under the detection limit.

Chromatography, High Pressure Liquid↗
PubMed1995

N-oxygenation of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine by the rat liver flavin-containing monooxygenase expressed in yeast cells.

N-oxygenation of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a dopaminergic neurotoxin, was studied using recombinant rat liver flavin-containing monooxygenase (FMO), FMO1A1, expressed in yeast cells. The mean (+/- S.D.) kinetic parameters of MPTP N-oxygenation were: Km = 1.8 +/- 0.5 microM, Vmax = 9.5 +/- 1.6 nmol/mg per min, and Vmax/Km = 4.6 +/- 0.5 ml/mg per min. n-Octylamine, an activator of FMO, enhanced the MPTP N-oxygenation activity by 51%, while methimazole, thiobenzamide and alpha-naphthylthiourea, alternate substrates of FMO, inhibited it by 27.4, 68.0 and 59.2%, respectively. The results indicate that MPTP is efficiently N-oxygenated by the recombinant rat liver FMO1A1, and that the responses to the modulators of FMO activity found in the recombinant rat liver FMO1A1 resemble those of mouse and rat liver microsomes as reported previously. The findings suggest that the recombinant FMO expressed in yeast cells is considered as a useful tool to study an involvement of FMO in the metabolism of environmental toxins or chemicals. In addition, FMO1A1 appears to be one of the predominant enzymes responsible for the N-oxygenation of MPTP at least in rat liver.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1995

Nitric oxide synthase containing nerves in the atrioventricular node of the guinea pig heart.

Immunoelectron microscopy was performed to localize immunoreactivity for nitric oxide synthase (NOS) in the guinea-pig atrioventricular node. Many small ganglia were found in the interatrial septum near the atrioventricular node. A small number of neurons in these ganglia were immunoreactive. NOS immunoreactive axons were observed in nerve bundles near or within the node. Very thick immunoreactive axons, 8-10 microns in diameter, were found between the conductive tissue and the ordinary cardiac muscles. Electron-microscopic examination confirmed that these axons were unmyelinated. Nerve bundles in this region contained both myelinated and unmyelinated axons; however, immunoreactivity was detected exclusively in unmyelinated axons. Fine NOS-immunoreactive nerve fibers with terminal varicosities were often seen in the atrioventricular node. Close contact between NOS-immunoreactive axon varicosity and specialized cardiac muscle cell was observed. Intranodal ganglia were observed among the specialized cardiac muscles. They were surrounded by numerous axons, some of them were immunoreactive. Direct axo-somatic synapses from NOS-immunoreactive terminals to the intranodal ganglion cells were observed. The present results indicate a possibility that nitric oxide plays a role in the neural control of the conductive tissue in the heart through direct neuromuscular contact.

Amino Acid Oxidoreductases↗
PubMed1995

Cavernous lymphangioma of the breast: case report of an infant.

Ultrasonography and magnetic resonance imaging (MRI) were used to assess a 4-month-old male infant with a multicystic tumor of the left breast that was identified at birth. The tumor was removed surgically following the diagnosis of a cavernous hemangioma. Only seven similar cases of lymphangioma of the breast have been reported. We review these cases in conjunction with our own findings.

Breast Neoplasms, Male↗
PubMed1995

Right pneumonectomy syndrome: report of two cases.

We report herein the cases of two infants who developed right pneumonectomy syndrome, both of whom were born with gross C-type esophageal atresia (EA/TEF), and a hypoplastic right lung arising from the lower esophagus, being a bronchopulmonary foregut malformation (BPFM). Appropriate and well-timed treatments for a variety of sequelae primarily caused by the mediastinal shift must be considered after right pneumonectomy in early childhood.

Bronchi↗
PubMed1995

Establishment of primary epithelial cell culture from elutriated rat gastric mucosal cells.

Proliferating cells in the gastric mucosal epithelium were successfully enriched by counterflow elutriation in a medium-sized cell fraction. When inoculated on culture plates coated with E-C-L cell attachment matrix, these cells differentiated into mucus-producing cells after reaching confluence. Northern blot analysis did not detect any transcript of the proton pump, histidine decarboxylase, somatostatin, or pepsinogen I, indicating the absence of parietal, ECL, D, and chief cells in the confluent monolayer. These mucus-producing cell monolayers that respond to various growth factors may be a suitable model with which to investigate the function of gastric mucus cells in vitro.

Animals↗
PubMed1995

Randomized control trial of lipo-prostaglandin E1 in patients with acute liver injury induced by lipiodol-targeted chemotherapy.

OBJECTIVE: The aim of this study was to prove whether lipo-prostaglandin E1 (PGE1)/glucagon insulin therapy combination could prevent the acute liver dysfunction induced by Lipiodol (iodized oil)-targeted chemotherapy for hepatocellular carcinoma. METHODS: This study was a randomized control trial. Patients in two groups (groups A and B: n = 29) were each given an intravenous injection of 10 units of insulin and 1 mg glucagon every 12 hours for 1 week after Lipiodol-targeted chemotherapy. Patients in group B (n = 11) were each given an intravenous injection of 20 micrograms lipo-PGE1 every 12 hours over 1 week. Several items, including conventional liver function tests, were evaluated at the start of the study and on the days 1, 2, 4, 7, and 14 after Lipiodol-targeted chemotherapy. RESULTS: Combined lipo-PGE1/glucagon-insulin therapy can prevent the elevation of serum ALT level and total bilirubin level after Lipiodol-targeted chemotherapy. In the group A (glucagon-insulin therapy only), the maximum level in the follow-up interval was statistically higher than that in the pretreatment level (p < 0.05), whereas there was no significant difference in group B (treated with combined glucagon-insulin therapy and lipo-PGE1). Changes of ALT level in group B tend to be lower than in group A; however, there was no significant statistical difference. There were few episodes of side effects in both groups. CONCLUSION: Combined lipo-PGE1/glucagon-insulin therapy may be a safe and effective treatment for the prevention of acute hepatic failure.

Aged↗
PubMed1995

Copresence of prostaglandin EP2 and EP3 receptors on gastric enterochromaffin-like cell carcinoid in African rodents.

BACKGROUND & AIMS: Prostaglandins (PGs) have important roles in the regulation of gastric acid secretion. The aim of this study was to examine the possible presence of PG receptors on the gastric enterochromaffin-like (ECL) carcinoid of Mastomys natalensis, which might be a useful model of normal ECL cells. METHODS: A [3H]PGE2 binding experiment was performed by using the ECL tumor membrane, and intracellular signal transduction was studied in the cells. In addition, Northern blot analysis using EP2 and EP3 receptor complementary DNAs was conducted. RESULTS: [3H]PGE2 specifically bound to the tumor cell membrane, and the binding was displaced by various PGs with a potency order of PGE1 = PGE2 > enprostil > PGF2 alpha. Although PGE1 and PGE2 stimulated 5'-cyclic adenosine monophosphate (cAMP) production, neither PGF2 alpha nor enprostil had any effect. On the other hand, all of PGE1, PGE2, PGF2 alpha, and enprostil attenuated the forskolin-induced cAMP production. Moreover, enprostil inhibited histamine release induced by forskolin. However, on pertussis toxin treatment, PGE2 paradoxically enhanced the forskolin-induced increase of cAMP production. Finally, the presence of EP2 and EP3 receptor messenger RNAs was confirmed by RNA blot analysis. CONCLUSIONS: The ECL carcinoid tumor cells of Mastomys seem to possess two subtypes of PGE receptor: EP2 linked to cAMP production and EP3 coupled with inhibitory guanosine 5'-triphosphate-binding proteins mediating the inhibition of cAMP production.

Animals↗
PubMed1995

Mesenteric teratoma in an 8-month-old girl.

The authors report the case of a solid, mature teratoma of the mesentery occurring in an 8-month-old girl. The tumor was enucleated from the ileocecal mesentery. Histologically the tumor included all three embryonal layers. This is the youngest patient reported to have mesenteric teratoma.

Female↗
PubMed1995

Nitric oxide synthase-immunoreactive vagal afferent fibers in rat superior cervical ganglia.

Chronic (5-14 days) preganglionic denervation of the rat superior cervical ganglia by sectioning the cervical sympathetic trunk resulted in a time-related partial or complete loss of nitric oxide synthase (isoform I)-immunoreactive fibers and terminals surrounding many sympathetic ganglionic neurons. Unexpectedly, denervation unmasked many varicose nitric oxide synthase-immunoreactive fibers, some of which could be traced the entire length of the superior cervical ganglia. Injection of the retrograde tracer Fluorogold into the superior cervical ganglia labeled a population of nodose ganglion cells and of dorsal root ganglion cells from C8 to T3 segments. When the same sections were processed for nitric oxide synthase-immunoreactivity, 40% of the Fluorogold-containing nodose ganglion cells also expressed nitric oxide synthase-immunoreactivity, whereas colocalization was observed in only a few dorsal root ganglion cells. Similarly, injection of Fluorogold into denervated superior cervical ganglia labeled a population of nodose ganglion cells. Sectioning of all nerve trunks associated with the superior cervical ganglion prior to injection of Fluorogold, except the cervical sympathetic trunk, resulted in no detectable labeling of Fluorogold in the ipsilateral nodose ganglion cells. These results indicate that a population of rat nodose ganglion cells contain nitric oxide synthase and that some of these neurons project their axons through the superior cervical ganglion and terminate in the peripheral target tissues. The possibility that nitric oxide synthase-immunoreactive vagal afferent fibers may participate in nociception is considered.

Afferent Pathways↗
PubMed1995

Dermatoglyphic (fingerprint) pattern in biliary atresia.

The dermatoglyphic (fingerprint) patterns of 288 patients with biliary atresia (117 males and 171 females) were compared to those of normal Japanese. Arches and radial loops were seen more frequently than the normal distribution on thumb, ring- and little-fingers. Nineteen percent of the patients had abnormal fingerprint patterns.

Biliary Atresia↗
PubMed1995

Glycosylated human recombinant interleukin-1 alpha, neo interleukin-1 alpha, with D-mannose dimer exhibits selective activities in vivo.

To investigate the effect of carbohydrate-introduction on IL-1 activity, especially in vivo, and to develop IL-1 with less deleterious effects, recombinant human IL-1 alpha was coupled with mannose dimer, alpha-D-Man-1-6-D-Man [Man2 alpha(1-6)] by an acyl azide method. Previous studies demonstrated that the glycosylated IL-1 exhibited reduced activities compared with original IL-1 in all the experiments performed in vitro. In this study, we investigated the in vivo activities of Man2 alpha(1-6)-conjugated IL-1 alpha. The glycosylated IL-1 alpha exhibited very low pyrogenic activity and alpha 1-acid glycoprotein induction compared with untreated IL-1 alpha. Untreated IL-1 alpha increased the serum level of IL-6, but the glycosylated IL-1 alpha did not. However, the glycosylated IL-1 alpha possessed the same potency as untreated IL-1 alpha in reduction of serum levels of glucose and triglyceride and in recovery of peripheral white blood cells in 5-fluorouracil-treated mice. Therefore, glycosylation of IL-1 appeared to be useful for the development of neoIL-1 with selective activity in vivo.

Animals↗
PubMed1995

The rat intrinsic factor gene: its 5'-upstream region and chief cell-specific transcription.

A DNA segment containing the 5'-upstream region and amino terminal reading frame of the gastric intrinsic factor gene was cloned from rat and its nucleotide sequence was determined. S1 mapping demonstrated that the transcription initiation site is located downstream of the second TATA-box sequence. Similar sequence motifs to those in the pepsinogen genes transcribed in gastric chief cells were found in the deduced sequence, suggesting that the rat intrinsic factor gene is transcribed in these cells. The genes for the intrinsic factor and its homologous protein transcobalamin I were apparently derived from a common ancestoral gene, since the positions of their intron insertions as well as the amino acid residues are conserved. Northern blot hybridization showed that the gene for the intrinsic factor is transcribed in the stomach but not detectably in the intestine, kidney, testis, brain, heart, liver, lung, or spleen. In situ hybridization using radioactive complementary RNA clearly indicated that the major transcription site in gastric glands is chief cells. Different locations of expression of intrinsic factor proteins in various mammals were observed previously using antibodies: in rat parietal cells and chief cells, in mouse chief cells, and in human parietal cells. The present results clearly demonstrated the intrinsic factor mRNA mainly in chief cells of adult rats, as in mice, suggesting that transcriptional regulation of the intrinsic factor gene is essentially the same in rodents.

Animals↗
PubMed1995

Evaluation of gastric ulcer healing by lansoprazole by measurement of ulcer diameter.

Ninety-three patients with gastric ulcers larger than 10 mm in diameter were randomly divided into two groups. Seventy patients received lansoprazole 30 mg once daily and 23 patients received cimetidine 400 mg twice daily. Ulcer healing was assessed by measuring changes in the longitudinal diameter of the ulcer at 2, 4, and 8 weeks after the start of treatment. In the lansoprazole group, ulcer diameters became significantly smaller than those in the cimetidine group. In the lansoprazole group, ulcer diameters did not differ significantly between patients younger than 65 years of age and those 65 or older at the evaluation points. However, in the cimetidine group, ulcer diameters became much smaller in patients younger than 65 years of age than in older patients. These results suggest that the potent acid suppression afforded by lansoprazole led to effective healing of gastric ulcers even in elderly gastric ulcer patients with defective mucosal protection.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1995

Immunohistologic studies on subpopulations of lymphocytes in cattle with enzootic bovine leukosis.

The distribution of subpopulations of lymphocytes in lymph nodes and tumors from cattle with enzootic bovine leukosis (EBL) was examined by immunohistochemistry using a panel of monclonal antibodies against leukocyte differentiation molecules of EBL. The lesions in lymph nodes could be divided into three types based on the extent of infiltration and proliferation of neoplastic cells with provirus and differential expression of leukocyte differentiation molecules. The number of B-B2+, sIgM+ cells was reduced in frequency in follicles during the neoplastic cell proliferation. CD4- and CD8-positive alpha/beta T cells and gamma/delta T cells positive for WC1 (workshop cluster designation) were also reduced in frequency in areas infiltrated with neoplastic cells. Almost all neoplastic cells were B-B2- and IgM-positive. However, there were a few B-B2- and/or IgM-negative cells or cells stained faintly in all cases. WC1+ cells were not observed in tumor tissues. However, CD4+ and CD8+ cells were observed throughout tumor tissues, suggesting a role for these cells in tumor immunity.

Animals↗