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Biomedical subjects

M Minami

Publications and source records attributed to M Minami.

At least 487 records · Page 27Linked to original sources
PubMed1991

[Effects of diaphragm plication for phrenic nerve paralysis on respiratory mechanics and diaphragm function].

The purpose of this study is to examine the effects of unilateral diaphragm plication for phrenic nerve paralysis on the respiratory mechanics and diaphragm function. Study 1: We performed thoracotomy (BASELINE), left phrenicotomy (INJURY) and left diaphragm plication (PLICATION) in ten dogs. After chest was closed in each condition, measured were the tidal volume (TV), respiratory rate (f), esophageal and gastric pressure swing (delta Pes, delta Pga), dynamic compliance (Cdyn) the ratio of gastric to esophageal pressure swing (delta Pga/delta Pes) and the work of breathing per liter (WOB/L) under stable spontaneous breathing. Study 2: In eight other left-phrenicotomized dogs, Pdi and fractional shortening of the costal diaphragm during contralateral electrophrenic stimulation were measured before and after plication. After plication TV, delta Pga/delta Pes, Cdyn, Pdi and fractional shortening during stimulation increased significantly, whereas Pes and WOB/L decreased significantly compared with INJURY condition. In conclusion unilateral diaphragm plication after paralysis improves the intact hemidiaphragm contractility and diaphragmatic contribution to breathing.

Animals↗
PubMed1990

Leukotriene A4 hydrolase is a zinc-containing aminopeptidase.

A comparison of amino acid sequences revealed that leukotriene A4 (LTA4) hydrolase is homologous to various types of aminopeptidases. Consistently with the finding, the purified LTA4 hydrolases from both human and guinea pig sources contained equimolar zinc ion, as determined by atomic absorption spectrometry. The enzyme had a significant amount of aminopeptidase activity toward synthetic peptide substrates. Both LTA4 hydrolase and aminopeptidase activities were inhibited by o-phenanthroline, p-chloromercuribenzoic acid, and Leu-thiol with similar IC50 values. Co-purification as well as co-immunoprecipitation of both enzyme activities with an affinity-purified antibody against LTA4 hydrolase strongly suggest that the two enzyme activities reside in a single protein.

Aminopeptidases↗
PubMed1990

The allorecognition of H-2Kb-specific CD4-CD8- T cell hybridomas is influenced by the substitution at residue 256 of MHC class I molecules.

Our previous studies demonstrated that allorecognition of HTB176.10 and HTB177.2, H-2Kb-reactive CD4-CD8- T cell hybridomas is markedly influenced by the exchange of the alpha 3 domain between H-2Kb and H-2Dp. The recombinant genes of the exon 4 between H-2Kb and H-2Dp were constructed to determine the residues of the alpha 3 domain that influence the allorecognition of these T cell hybridomas. Seven recombinant genes of the exon 4 were generated by in vivo recombination in Escherichia coli. Chimeric genes containing these recombinants were transfected into L cells and the transfectants expressing equivalent amounts of chimeric molecules were selected by flow cytometry. Studies on responses of these T cell hybridomas to the chimeric molecules confirmed our previous observation that the primary structure of the alpha 3 domain influences the allorecognition by the hybridomas. Moreover, it was indicated that residue 256 on the alpha 3 domain markedly affects the allorecognition by the T cell hybridomas, although substitutions at residues 184, 193, 195, 197, 262, and 264 exerted some effects on the T cell recognition. Further studies with the use of a single amino acid mutant of H-2Kb at residue 256 confirmed the effect of substitution at residue 256 on allorecognition of the T cell hybridomas. Taken together, results of this study demonstrated that polymorphism of the alpha 3 domain is indeed involved in the formation of allodeterminants recognized by TCR.

Amino Acid Sequence↗
PubMed1990

Convulsants induce interleukin-1 beta messenger RNA in rat brain.

The effects of systemic administration of kainic acid and pentylenetetrazol on interleukin-1 beta gene expression in the rat brain was studied. After the administration of kainic acid in a convulsive dose (10 mg/kg i.p.), Interleukin-1 beta mRNA was induced intensely in the cerebral cortex, thalamus and hypothalamus, moderately in the hippocampus and weakly in the striatum, but not in the midbrain, pons-medulla and cerebellum. Pentylenetetrazol induced Interleukin-1 beta mRNA in the cerebral cortex, hypothalamus, and hippocampus with a faster time-course than kainic acid. Diazepam suppressed both the convulsion and the induction of Interleukin-1 beta mRNA produced by kainic acid. Dexamethasone suppressed the induction of Interleukin-1 beta mRNA, but did neither the convulsion nor the induction of c-fos mRNA following the injection of kainic acid. These results provide the first evidence that intensive neuronal excitation induces Interleukin-1 beta mRNA in particular regions of the brain.

Animals↗
PubMed1990

Molecular evolution and zinc ion binding motif of leukotriene A4 hydrolase.

Leukotriene A4 (LTA4) hydrolase belongs to the aminopeptidase N family. In order to investigate the molecular evolution and physiological significance of LTA4 hydrolase, the enzymes belonging to the family were aligned and a phylogenetic tree was constructed. From the alignment, it was found that three residues involved in zinc binding and one residue of the active sites of aminopeptidases N were conserved in LTA4 hydrolase. In agreement with the observation, LTA4 hydrolase is a zinc protein as determined by atomic absorption spectroscopy.

Amino Acid Sequence↗
PubMed1990

Immunological quantitation and immunohistochemical localization of leukotriene A4 hydrolase in guinea pig tissues.

We prepared a highly specific polyclonal antibody against leukotriene (LT) A4 hydrolase using a recombinant human enzyme. Using this antibody, we quantified LTA4 hydrolase protein content in the cytosols of guinea pig tissues. The enzyme protein content correlated well with the enzyme activity with a correlation coefficient of 0.87. However, the enzyme activity per mg of the enzyme in the cytosols was low, particularly in the liver and adrenal gland, compared with the specific activity of the purified enzyme. These observations suggest the presence of inhibitory substances and/or inactive enzymes in the cytosols of these tissues. To determine the cellular localization of LTA4 hydrolase in tissues other than blood cells, we carried out immunohistochemical examinations of guinea pig tissues. We identified epithelial cells in the tracheobronchial system and gastrointestinal tract, smooth muscle cells in the bronchi and aorta, vascular endothelial cells, and the intestinal plexus as novel cellular sources of the enzyme in the parenchyme of the tissue. Thus, LTA4 hydrolase was widely distributed in various types of parenchymal cells in the tissues, and this observation warrants further investigations on the biological activities of LTB4 in these cells and tissues.

Animals↗
PubMed1990

Studies on the uptake of N-methylisoquinolinium ion into rat striatal slices using high-performance liquid chromatography with fluorimetric detection.

A simple and sensitive procedure for the measurement of N-methylisoquinolinium ion (NMIQ+), a putative neurotoxin, was devised using high-performance liquid chromatography (HPLC) with fluorescence detection. Separation of NMIQ+ was carried out by gel filtration and reversed-phase HPLC on a column of hydrophilic polymer gels (Asahipak GS-302H). The method was sensitive enough to measure 50 fmol of NMIQ+. Uptake of NMIQ+ into rat striatal slices was confirmed by this method.

Animals↗
PubMed1990

Tyrosine hydroxylase, tryptophan hydroxylase, biopterin, and neopterin in the brain of anorexia nervosa.

The activities of tyrosine hydroxylase and tryptophan hydroxylase and contents of biopterin and neopterin were measured for the first time in various regions of human brain from a patient with anorexia nervosa (AN). In AN as compared with controls, tyrosine hydroxylase activity was markedly reduced in all brain regions analyzed, while tryptophan hydroxylase activity and biopterin content had a tendency to increase. Neopterin content did not change dramatically. The opposite changes of tyrosine hydroxylase and tryptophan hydroxylase suggest an imbalance between the activity of catecholaminergic neurons and that of serotonergic neurons, and may be related to pathogenesis of AN.

Adult↗
PubMed1990

Somatostatin is increased in the dorsal root ganglia of adjuvant-inflamed rat.

To determine whether biosynthesis of somatostatin is enhanced in the primary sensory neurons by inflammatory pain, we examined the effects of adjuvant inoculation on the content of immunoreactive somatostatin, mainly composed of somatostatin-14 and somatostatin-28, in the dorsal root ganglia and the spinal cord of the rat. The adjuvant inoculation, which produced long-lasting inflammation and hyperalgesia, increased the content of immunoreactive somatostatin, especially somatostatin-14, in the dorsal root ganglia at L4-L6 levels with no change in the dorsal and ventral horns of lumbar enlargement. Such an increase was enhanced by an intrathecal injection of colchicine (0.2 mg) that inhibits axonal flow of somatostatin. Chronic administration of the anti-inflammatory analgesic, sodium diclofenac (3 mg.kg-1.d-1), abolished an adjuvant-induced increase in the content of immunoreactive somatostatin in the dorsal root ganglia. These results suggest that the turnover (biosynthesis and axonal flow) of somatostatin in the primary sensory neurons is enhanced in the presence of persisting inflammatory pain, and support the idea that somatostatin-containing primary afferents are involved in the transmission of pain in the spinal dorsal horn.

Animals↗
PubMed1990

Bam HI restriction fragment length polymorphisms for hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene of carriers and controls of HPRT deficiency in Japan.

Three-allele restriction fragment length polymorphisms (RFLPs) for the restriction endonuclease Bam HI are known at the hypoxanthine-guanine phosphoribosyltransferase (HPRT, E.C.2.4.2.8.) gene locus. The alleles are expressed phenotypically on Southern blots as three distinct pairs of fragments that hybridize to HPRT cDNA: i) a 22-kilobase (kb)/25-kb pair, ii) a 12-kb/25-kb pair, and iii) a 22-kb/18-kb pair. Allele frequencies in 119 unrelated Japanese people were 0.38 for the 22-kb/25-kb allele, 0.43 for the 12-kb/25-kb allele, and 0.19 for the 22-kb/18-kb allele, an average heterozygosity of 66% in Japanese females, a higher rate than in Caucasian females. Five out of nine carriers of partial or complete HPRT deficiency showed heterozygous patterns for Bam HI RFLPs.

Blotting, Southern↗
PubMed1990

Determination of bicarbonate output using pH deflection in the rat duodenum: influences of prostaglandins and cholinergic agents.

We set up a system to measure the luminal pH, potential difference (PD) and bicarbonate output in the anesthetized rat duodenum, and investigated these responses caused by prostaglandins (PGs) and cholinergic agents. When the proximal duodenum (1.7 cm) was perfused at a flow rate of 0.7 ml/min with saline adjusted to pH 4.5, the duodenal pH, PD and HCO3- output were 5.5 to 6.0, -4 to -6 mV and 1.2 to 1.6 muEq/10 min, respectively; they were markedly reduced by i.v. injection of saturated KCl. Both natural (PGE1, PGE2) and synthetic (PGE2, PGl2) PGs, given either s.c. or i.v., significantly elevated all these parameters, while indomethacin (s.c.) decreased the pH as well as the PD. Small but significant increases of the pH were observed after i.v. administration of cholinergic agents (carbachol, bethanechol), a GABAergic agent (baclofen) and an analogue of thyrotropin releasing hormone (YM-14673), with a temporal elevation of the PD; the degree of net HCO3- output caused by these agents was 20-50% of the values obtained with PGE2 (100 micrograms/kg, i.v.), and they were significantly reduced in the presence of atropine. These results suggest that (a) the system using pH deflections can be used to sensitively detect HCO3- output in the rat duodenum, and (b) duodenal acid neutralizing capacity may be regulated by central and peripheral cholinergic systems as well as endogenous PGs.

Alprostadil↗
PubMed1990

Emesis-related biochemical and histopathological changes induced by cisplatin in the ferret.

Cisplatin is an effective antineoplastic agent that causes severe vomiting due to unknown mechanism. The ferret, an animal model useful in the determination of emetic activity, was used to clarify the emesis-related biochemical and histopathological changes that were induced by cisplatin. Cisplatin (5 to 10 mg/kg) was administered intraperitoneally and a 7-10 mg/kg i.p. dose evoked dose-dependent emesis in the ferret. Almost all cisplatin-vomiting episodes occurred within a 6 hour observation period. All ferrets receiving cisplatin in this study died within 3-5 days. Significant increases in ileal mucosal levels of serotonin and norepinephrine were observed in cisplatin-treated ferrets. There were no significant changes in the levels of serotonin and dopamine in the gastric mucosa. Also, karyorrhexis was observed in the epithelial cells of the ileum and in the lymph follicles of the spleen of cisplatin-treated ferrets. These significant biochemical and pathological changes in the ileum may play an important role in cisplatin-induced emesis.

Animals↗
PubMed1990

[Transarterial embolization of metastatic pheochromocytoma].

We successfully controlled hypertension of a 48-year-old female by embolizing metastatic pheochromocytoma of the liver. Although transarterial embolization of the hepatic artery was uneventful, the patient soon developed severe hypertension and tachycardia which were controlled medically. Symptoms subsided within 10-20 days. Follow-up CT showed reduction of the liver mass.

Adrenal Gland Neoplasms↗
PubMed1990

[Pharmacokinetics and clinical evaluation of aztreonam in pediatric surgery].

Pharmacokinetic and clinical studies on aztreonam (AZT) in pediatric surgery were performed and results obtained are summarized below. 1. Plasma and urinary levels of AZT were measured in 6 neonate patients following drip-infusion for 1 hour of AZT (dose of AZT: 20 mg/kg). Plasma levels reached their peak (42.3-50.4 micrograms/ml) at the end of infusion or in 1 hour thereafter except in case 2. In case 2, plasma level reached its peak (36.6 micrograms/ml) at 2 hours after the end of infusion. Plasma levels of AZT decreased rapidly after reaching their peaks, and plasma half-lives (T 1/2) were 1.85-2.84 hours. Urinary recovery rates were 15.7-65.3%. 2. Bile levels of AZT were determined in 8 patients with biliary atresia following 1 hour drip-infusion of AZT (dose of AZT: 20 mg/kg for 4 patients, 40 mg/kg for the other 4 patients). In the 20 mg/kg group, peak levels of AZT in bile were noted 2 hours after the end of infusion, and they were 3.7-7.1 micrograms/ml. Recovery rates in bile in the first 6 hours after the end of infusion were 0.34-0.9%. In the 40 mg/kg group, peak levels of AZT in bile were found at 2 hours and 2-4 hours after the end of infusion, and they were 4.9-8.8 micrograms/ml. Recovery rates in bile in the first 6 hours after the end of infusion were 0.03-0.33%. 3. AZT and ampicillin were administered to 6 patients as prophylaxis against postoperative infections. Another patient with postoperative cholangitis was given AZT alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Aztreonam↗
PubMed1990

Methemoglobinemia with oxidized hemoglobins and modified hemoglobins found in bloods of workers handling aromatic compounds and in those of a man who drank cresol solution.

We found that half-oxidized hemoglobins such as (alpha 2+ beta 3+)2 and (alpha 3+ beta 2+)2, and methemoglobin were significantly increased in the erythrocytes of workers handling chemical compounds in a chemical plant of Japan. In addition, we found two unusual anodic hemoglobins (hemoglobin X and hemoglobin Y) to be present to a large extent in the erythrocytes of the workers investigated (21 persons), using isoelectric focusing electrophoresis on polyacrylamide gel plates. For example, the hemoglobin analysis of a worker showed: hemoglobin X, 6.2%; hemoglobin Y, 26.8%; hemoglobin A + hemoglobin F, 54.5%, half-oxidized hemoglobins, 9.8%; methemoglobin, 1.5%; hemoglobin A2, 2%. Since contents of hemoglobin A decreased by more than 40% of normal levels, and those of oxidized and modified hemoglobins increased up to 40% of total hemoglobins in the erythrocytes of several workers in the plant, we may consider these cases as ones having toxic methemoglobinemia with oxidized and modified hemoglobins. The changes of intracellular hemoglobins in these cases may be due to oxidation and modification of the proteins by chemical compounds absorbed from skin and lungs. Therefore, these hemoglobins may be a good indicator to monitor the health of workers in chemical plants. We also studied the formation mechanism of modified hemoglobins such as hemoglobin X and hemoglobin Y, investigating the reactions of hemoglobin with various aromatic compounds in vitro. On the other hand, we had the opportunity to analyze the changes in oxidized hemoglobins and modified hemoglobins in the blood of a man who drank cresol solution to commit suicide and was sent to a hospital.(ABSTRACT TRUNCATED AT 250 WORDS)

Cresols↗