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Biomedical subjects

M Minami

Publications and source records attributed to M Minami.

At least 415 records · Page 23Linked to original sources
PubMed1994

Retroperitoneal fibrosis leading to extrahepatic portal vein obstruction.

A very rare case of highly probable retroperitoneal fibrosis leading to extrahepatic portal obstruction is described. The patient was a 44-year-old woman with right pleural effusion and splenomegaly. Computed tomography indicated a large accumulation of soft tissues in the retroperitoneum, and abdominal angiography showed extensive portal obstruction. A twenty-year-long abuse of analgesics is suspected to have caused the retroperitoneal fibrosis.

Adult↗
PubMed1994

Biological effects of diesel exhaust particles (DEP) on isolated cardiac muscle of guinea pigs.

Diesel engine-powered vehicles emit some 30 to 100 times more particles than do gasoline engine cars. We previously reported that diesel exhaust particles (DEP) could produce superoxide anions in an in vitro study. Furthermore, mice instilled intratracheally with DEP showed high mortality at low doses. The cause of death was lung edema with damage to the lung endothelial cells. In order to elucidate the mechanism of the onset of mortality induced by DEP, we examined the direct action of DEP on the isolated atrium of guinea pigs. A light-duty (2740cc), four cylinder diesel engine was used. The DEP were collected on fiberglass filter. DEP caused a negative inotropic action that was followed by the cardiac arrest of the isolated left atrium. These actions were not inhibited by propranolol, atropine, verapamil, diltiazem, diphenhydramine, indomethacin, superoxide dismutase or catalase. The precise mechanism of cardiac arrest is unknown. However, these results suggest that cardiac toxicity induced by DEP might be involved in lung edema.

Animals↗
PubMed1994

[Prevention of coronary spasm during and shortly after coronary revascularization in patients with variant angina].

From June 1990 to March 1993, 9 patients undergoing coronary artery bypass grafting (CABG), 4.4% of all CABG cases at our hospital during this period, had significant perioperative coronary spasm. For 4 patients who underwent CABG before May 1992 (Group 1), preventive and suppressive procedures for the coronary spasm were the addition of diltiazem in the cardioplegic solution and the continuous intravenous infusion of nitroglycerin. Perioperative myocardial infarction (PMI) occurred in all 4 patients in Group 1, with the mean peak MB-CPK of 356 +/- 197 IU/l. One patient had delayed sternal closure because of his unstable hemodynamic status. Thereafter, we changed our protocol as follows: 1) Ergometrine loading (intracoronary infusion) test was performed in all candidates for CABG, aiming at finding out patients with a high risk. And for the high-risk patients, in addition to the measures done in Group 1, 2) intraaortic balloon pumping was performed through the perioperative period, and 3) a pig-tail catheter was dwelled in the Valsalva sinus, through which bolus doses of isosorbide dinitrate were injected frequently in this period. 4) Additionally nifedipine was periodically administered through the nasogastric tube. With these intensive preventive/suppressive measures, the perioperative spasm in 5 patients (Group 2) with variant angina were successfully managed, with no resultant PMI nor operative death (The occurrence of PMI was significantly less frequent in Group 2 than in Group 1, with the p value < 0.05). For patients with variant angina undergoing CABG, combined intensive preventive/suppressive measures for perioperative coronary spasm as listed above proved effective.

Adult↗
PubMed1994

[Aortic valve replacement in a patient with severely calcified small aorta valve and ascending aorta].

A 74-year-old male with severely calcified aortic valve and ascending aorta underwent aortic valve replacement. Cannulation as well as cross clamping of the ascending aorta was avoided because there might be a definite risk of cerebral embolism caused by liberated atheromatous debris on manipulation of the ascending aorta. The extracorporeal circulation was established by femoral arterial and right atrial cannulation, and the aorta was cross-clamped at the soft distal arch. Selective cerebral perfusion catheters were inserted via a longitudinal aortotomy made at a soft anterior portion of the ascending aorta, through which the valve replacement procedure was carried out. The aortic valve annulus was narrow (barely 21 mm in diameter), so that the interrupted mattress suturing technique with the pledgets placed below the annulus in the left ventricular outflow tract was adopted. By this supraannular suturing method a bioprosthesis was easily secured above the annulus as the thickened annulus was compressed between the sutures and the device.

Aged↗
PubMed1994

Immunotherapy for Stewart-Treves syndrome. Usefulness of intrapleural administration of tumor-infiltrating lymphocytes against massive pleural effusion caused by metastatic angiosarcoma.

We describe a 56-year-old woman with Stewart-Treves syndrome who had severe dyspnea from a pleural effusion caused by metastatic angiosarcoma in the right lung. Tumor-infiltrating lymphocytes (TIL) in the pleural effusion were cultured and expanded in vitro in the continuous presence of recombinant interleukin 2 with periodic stimulation by CD3 antibody. The expanded TIL were administered intrapleurally seven times at 1- to 4-week intervals in combination with intravenous infusion of recombinant interleukin 2. A panel of T-cell clones was also obtained from TIL. Immunotherapy dramatically improved the patient's dyspnea and pleural effusion. A CD4+ T-cell clone and a CD8+ T-cell clone established from TIL had specific cytotoxicity to the tumor cells.

Breast Neoplasms↗
PubMed1994

Effect of omentopexy on wound healing of the extensively detached and anastomosed canine trachea.

BACKGROUND: To examine the beneficial effect of omentopexy for tracheal anastomosis after extensive detachment that may cause impairment of the blood supply, the time course of tracheal wound healing was studied experimentally. METHODS: Circumferential resection of the trachea for three cartilage rings (nos. 11, 12, 13) and end-to-end anastomosis of the trachea were performed in 66 mongrel dogs, which were allocated to three groups (n = 22 in each). In the detached group, the trachea was entirely mobilized and isolated from the surrounding tissue for a length of 25 cartilage rings. In the wrapped group, omentopexy was added for the anastomosed site. In the control group, the same anastomosis was performed without omentopexy or detachment. The tracheal tissue blood flow was measured with a laser Doppler flow meter at the anastomosed site, and the tensile strength was determined with a tensiometer. RESULTS: All groups showed significant decreases in the blood flow on day 3, compared with the preoperative values, and increases stepwise from day 7 to day 21. On days 3, 7, and 14 the tissue blood flow was significantly (p < 0.01) higher in the wrapped group than in the detached group, although on day 21 it did not differ significantly among the three groups. The tensile strengths of the cartilaginous and membranous portions were significantly (p < 0.05) higher in the wrapped and control groups than in the detached group. On day 21, no significant intergroup differences were observed for this parameter. In the wrapped group and in the control group, the capillary network at the anastomosed site was well developed on day 7, and the tracheal mucosal epithelium was well regenerated on day 21 without granulation formation. CONCLUSIONS: This study showed that omentopexy at the anastomosed site of an extensively detached trachea provided adequate wound healing caused by rapid recovery of the tissue blood flow.

Anastomosis, Surgical↗
PubMed1993

In situ hybridization study of kappa-opioid receptor mRNA in the rat brain.

Distribution of kappa-opioid receptor mRNA in rat brain was examined by in situ hybridization technique. kappa-Opioid receptor mRNA was expressed in various brain regions, especially intensely in the neocortex (layer V and VI), caudate-putamen, nucleus accumbens, preoptic area, paraventricular thalamic nucleus, amygdala, several nuclei of hypothalamus, ventral tegmental area and substantia nigra pars compacta.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1993

The putative zinc-finger protein WZF1 interacts with a cis-acting element of wheat histone genes.

A nonamer motif (CATCCAACG) that is one of the cis-acting elements identified in the proximal promoter region of some wheat histone genes is included in the region that interacts with the wheat DNA-binding protein, HBP (histone gene-binding protein)-2. To obtain structural and functional information about this DNA-binding protein, we attempted to isolate a cDNA clone encoding HBP-2 on the basis of its ability to bind to a nonamer-containing 38-bp DNA fragment. Southwestern screening of a wheat cDNA library with concatenated 38-residue oligonucleotides as the probe produced one candidate clone. Nucleotide sequence analyses of this cDNA clone and the corresponding genomic clone showed that the protein deduced from the nucleotide sequence consisted of 261 amino acids and contained a set of zinc-finger motifs similar to those found in many eukaryotic transcription factors. The protein, named WZF1 (wheat zinc-finger protein 1), which was expressed from the cDNA in Escherichia coli cells, bound specifically and metal-ion-dependently to the nonamer-containing oligonucleotide. The WZF1 mRNA was highly expressed in the root apexes of wheat seedlings, but less so in the proximal portion of young leaves; whereas, histone H3 mRNA was highly expressed in both tissues. The expression patterns of the WZF1 and histone H3 genes in the early stages of germination differed, expression of the WZF1 gene being almost constant but not that of the H3 gene. The relationship of WZF1 and HBP-2 and the possible role of WZF1 in the histone gene expression were discussed.

Amino Acid Sequence↗
PubMed1993

Inhibition of tryptophan hydroxylase by 6,7-dihydroxy-N-cyanomethyl-1,2,3,4-tetrahydroisoquinoline, a cyanomethyl derivative of dopamine formed from cigarette smoke.

6,7-Dihydroxy-N-cyanomethyl-1,2,3,4-tetrahydroisoquinoline, a cyanomethyl derivative of dopamine formed from cigarette smoke, was found to inhibit the activity of tryptophan hydroxylase. The inhibition was non-competitive to the substrate L-tryptophan (the Ki value 7.25 +/- 0.81 microM), but not to the biopterin cofactor. The inhibition is irreversible. 6-Hydroxy-N-cyanomethyl-tetrahydro-beta-carboline, a cyanomethyl derivative of serotonin, is inactive towards the hydroxylase. 6,7-Dihydroxy-N-cyanomethyl-1,2,3,4-tetrahydroisoquinoline may affect the serotonin biosynthesis in vivo as a consequence of cigarette smoking.

Animals↗
PubMed1993

Cloning and expression of a cDNA for the rat kappa-opioid receptor.

We cloned a cDNA for the rat kappa-opioid receptor from a rat thalamus cDNA library. The deduced amino acid sequence consists of 380 residues with features shared by members of the G protein-coupled receptor family. The specific binding of [3H]bremazocine to the membrane of COS-7 cells transfected with the cDNA was displaced by kappa-specific opioid ligands, but not by mu- and delta-specific ligands. Xenopus oocytes injected with the in vitro transcribed mRNA responded to opioid ligands with the same subtype specificity. Northern blot analysis demonstrated that kappa-opioid receptor mRNA is expressed in a regionally specific manner in rat brain.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1993

Transendothelial migration activity of lymphokine-activated killer (LAK) cells.

With an in vitro static system using HUVEC (human umbilical vein-derived endothelial cells) cultured on type I collagen gel, we investigated the transendothelial migration activities of I1-2 activated killer (LAK) cells. Our results indicate that in comparison with unstimulated T cells, LAK cells exhibit strong transendothelial migration activity, as well as increased adhesiveness to HUVEC. Pretreatment of HUVEC for 24 h with rINF-gamma, rTNF-alpha and rIL-1 beta enhanced the LAK cell migration. The increase in the percentage of migration of LAK cells was greater than that of the percentage of adhesion but significantly less than the increase in the percentage of migration of resting T cells. The results of blocking studies using mAb strongly suggest that the enhanced migration of LAK cell was probably attributed to nonspecifically increased binding to HUVEC and markedly enhanced chemokinetic activity that was dependent primarily on the LFA-1 molecule. Among LAK cells, there were considerable differences in the migration activities of the various phenotypes. CD8+T-LAK migrated preferentially to CD4+T-LAK. CD16+ NK-LAK showed increased adhesion but somewhat decreased migration activities. However, rINF-gamma treatment of HUVEC for 24 h promoted vigorous migration of CD16+ NK-LAK, which suggests that endothelium regulate the migration of LAK cells. Based on these observations, we proposed that LAK cells, if transferred into tumor feeding vessels, can migrate into tumor tissue in considerable numbers and efficiently make contact with individual tumor cells to produce preferable clinical effects.

Cell Adhesion↗
PubMed1993

Two different promoters direct expression of two distinct forms of mRNAs of human platelet-activating factor receptor.

The human platelet-activating factor (PAF) receptor gene exists as a single copy on chromosome 1. We identified two 5'-noncoding exons, each of which has distinct transcriptional initiation sites. These exons are alternatively spliced to a common splice acceptor site on a third exon that contains the total open reading frame to yield two different species of functional mRNA (Transcript 1 and 2). Transcript 1 has consensus sequences for transcription factor NF-kappa B and Sp-1, and the Initiator (Inr) sequence homologous to the murine terminal deoxynucleotidyltransferase gene. Transcript 2 also contains consensus sequences for transcription factor AP-1, AP-2, and Sp-1. Transcripts 1 and 2 were both detected in heart, lung, spleen, and kidney, whereas only Transcript 1 was found in peripheral leukocytes, a differentiated human eosinophilic cell line (EoL-1 cells), and brain. Existence of distinct promoters was thus suggested to play a role in the regulatory control of PAF receptor gene expression in different human tissues and cells.

Alternative Splicing↗
PubMed1993

Inhibitory action of chloramine on formate-metabolizing system. Studies suggested by an unusual case record.

We previously reported on a patient exposed simultaneously to methyl chloride and chloramine gas who developed metabolic acidosis and permanent blindness [M. Minami et al., Hum Exp Toxicol 11: 27-34, 1992]. The case report suggested the possibility of potentiation of methyl chloride toxicity by chloramine. The potentiating mechanism was investigated by exposing mice to methyl chloride followed by ammonia chloramine, and then the level of formate in urine samples was measured with an enzyme coupling method to detect disturbance of formate metabolism. Mice dosed with 0.05 mL 1.0 mM chloramine after methyl chloride exposure excreted a significantly larger amount of urinary formate than mice treated with only methyl chloride. There was no difference in urinary formate levels between mice treated with only 0.05 mL 1.0 mM chloramine and those given only the vehicle (0.1 M phosphate buffer pH 6.0) for chloramine. The underlying biochemical mechanism of deterioration of formate metabolism was found to be the inhibition of the enzyme, N10-formyl tetrahydrofolate (N10-f-THF) dehydrogenase by 0.56-3.35 microM chloramine in the in vitro experiment using the purified enzyme. Positive control mice, given orally 0.1 mL 10% methanol in 0.1 M phosphate buffer (pH 6.0) excreted the same amount of urinary formate as those receiving 0.05 mL 1.0 mM chloramine after methanol administration. This was ascribed to the inhibitory effect of chloramine on formaldehyde dehydrogenase and depletion of substrate for further metabolism. The inhibition of the enzyme by chloramine (2.7-100.8 microM) was confirmed by in vitro experiments, using the purified enzyme, formaldehyde dehydrogenase.

Aldehyde Oxidoreductases↗
PubMed1993

Significance of pre-S region-defective hepatitis B virus that emerged during exacerbation of chronic type B hepatitis.

A defective form of the hepatitis B virus has been found in a patient with chronic type B hepatitis. Sequence analysis of the viral DNA after polymerase chain reaction amplification revealed a 117-base pair deletion (nucleotides 3129-53, subtype adr). This deletion includes the initiation codon of the pre-S2 region and a newly created in-frame stop codon in the pre-S1 region (nucleotide 3055) located 230 base pairs downstream from the pre-S1 initiation codon. This virus coexisted with the wild-type virus during the exacerbation period, as evidenced by an elevation of serum transaminase levels. It was not detected in the stable period, and the blood chemistry results were normal. We assayed antibodies against the mutation-related region by enzyme immunoassay in serial serum samples to clarify the mechanism of the emergence of this variant virus. Antibodies against the pre-S2 region were negative; however, the antibody response against the pre-S1 epitopes coincided with the appearance of the variant virus. These findings suggest that an activated T-cell and B-cell response had developed against the pre-S1 region during hepatic inflammation in this patient and that, consequently, selection occurred for a pre-S antigen-defective mutant strain of the virus that might be resistant to such an immune response.

Adult↗
PubMed1993

Coordinate gene expression of five subclass histones and the putative transcription factors, HBP-1a and HBP-1b, of histone genes in wheat.

The expression of genes encoding five histones (H1, H2A, H2B, H3 and H4) and the putative transcription factors HBP-1a (17) and HBP-1b (c38) was examined during early germination and in various tissues of young wheat seedlings. The steady-state levels of core histone (H2A, H2B, H3 and H4) mRNAs were coordinately cell cycle-dependent and paralleled the rate of DNA synthesis during early germination, whereas the expression pattern of the linker histone (H1) genes differed. The five subclass histone genes were actively expressed in the meristematic tissues of young seedlings. Moreover, H1 genes were expressed in leaves that consist mostly of non-proliferating cells, in which core histone genes showed little expression. Quantitative alterations to the mRNAs of the putative transcription factors HBP-1a (17) and HBP-1b (c38) of wheat histone genes were similar to those of the core histone mRNAs, suggesting that both factors function in the cell cycle-dependent expression of wheat core histone genes.

Base Sequence↗
PubMed1993

Angiographic findings of Meckel's diverticulum: the characteristic appearance of the vitelline artery.

Angiographic findings of the vitelline artery in five patients with surgically proven Meckel's diverticulum were reviewed retrospectively. Superselective vitelline arteriography was performed in two patients and superior mesenteric arteriography in three. Arteriography showed the elongated artery without branching originating from the distal ileal artery and a group of tortuous vessels at the distal portion of this artery in all patients. A dense capillary staining of the vitelline artery was exclusively shown in patients with ectopic gastric mucosa. In one patient, injection of methylene blue intraoperatively through a previously placed angiographic catheter into the vitelline artery stained only the vitelline artery and Meckel's diverticulum in blue but neither the mesentery nor the ileum. Demonstration of a nonbranching artery from the ileal artery and a group of dilated tortuous vessels at the distal portion of this artery should suggest the possibility of Meckel's diverticulum and can be confirmed by selective injection of the artery. It should be emphasized that angiography can detect Meckel's diverticulum even in the absence of acute bleeding.

Adolescent↗
PubMed1993

Inhibition of type A and B monoamine oxidase by 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinolines and their N-methylated derivatives.

6,7-Dihydroxy-1,2,3,4-tetrahydroisoquinoline (norsalsolinol) and 1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (salsolinol), and their N-methylated derivatives were found to inhibit type A and B monoamine oxidase isolated from human brain synaptosomal mitochondria. N-Methyl-norsalsolinol, (R) and (S) enantiomer of salsolinol, and N-methyl-salsolinols inhibited type A monoamine oxidase competitively to the substrate, kynuramine, and R enantiomers were more potent inhibitors than S enantiomers. The inhibition was reversible. Norsalsolinol induced positive cooperativity toward kynuramine. Both norsalsolinol and N-methyl-norsalsolinol inhibited type B oxidase non-competitively to the substrate, and their Ki values were much higher than those to type A. Types of inhibition of type A monoamine oxidase depended on the enzyme sources. Inhibition of monoamine oxidase by 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinolines is discussed in relation to their chemical structures.

Brain↗