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Biomedical subjects

M Hirano

Publications and source records attributed to M Hirano.

At least 253 records · Page 14Linked to original sources
PubMed1996

Effects of calcium antagonists nifedipine and flunarizine on phencyclidine-induced changes in the regional dopaminergic metabolism of the rat brain.

To elucidate the psychotropic actions of calcium (Ca) antagonists, we investigated the effect of the voltage-dependent Ca channel antagonists, nifedipine and flunarizine, on phencyclidine (PCP)-induced changes in the monoamine metabolism in the regional brain areas of rats. The results indicate that the administration of nifedipine alone attenuated dopamine (DA) metabolism in the nucleus caudatus putamen while enhancing serotonin (5-HT) metabolism. By contrast, flunarizine increased DA metabolism. PCP significantly increased DA metabolite levels in the prefrontal cortex, the nucleus caudatus putamen, and the amygdala. The PCP-induced increases in DA metabolism in these regions were significantly antagonized by nifedipine, but not by flunarizine. These results indicate that nifedipine attenuates the PCP-induced hyperactivity of the dopaminergic neurons, suggesting antipsychotic properties for this drug.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1996

Hemorrhage from abdominal non-Hodgkin's lymphoma treated successfully by emergency transcatheter arterial embolization.

A 49-year-old Japanese woman with follicular lymphoma who presented with severe abdominal and back pain is reported. She was known to have malignant lymphoma and had been previously treated with combination chemotherapy. An abdominal tumor occurring at the root of the mesentery and involving the superior mesenteric artery (SMA) had been diagnosed by computed tomography (CT), magnetic resonance imaging, and abdominal angiography. Emergent ultrasonography and CT findings showed intraperitoneal bleeding from the abdominal tumor. Selective SMA angiography revealed extravasation from a small branch originating from the dorsal pancreatic artery, which was embolized through a catheter by using platinum coils. It should be noted that a large tumor of malignant lymphoma, involving large vessels, may bleed, and in such a case selective transcatheter arterial embolization may be one of the effective modalities for hemostasis.

Abdominal Neoplasms↗
PubMed1996

Chromosome 12-linked autosomal dominant scapuloperoneal muscular dystrophy.

Scapuloperoneal syndromes are characterized by their distribution of muscle weakness and wasting. The reported pattern of inheritance has been variable. Both neurogenic and myopathic forms of autosomally dominantly inherited scapuloperoneal syndrome have been described. It has been suggested that these are variants of other neuromuscular diseases. We examined 44 members from a family with 14 members affected with a scapuloperoneal syndrome. Physiological and histological analysis implied that this condition is predominantly myopathic. Linkage analysis was done to confirm the genetic etiology of the disease in this family and to evaluate the possibility that it is a allelic variant of other neuromuscular diseases. Genetic analysis demonstrated linkage of the disease to chromosome 12, which makes it genetically distinct from other loci known to cause neuromuscular disease. Muscle fibers with hyaline desmin-containing cytoplasmic inclusions in combination with focal myopathic changes may be a disease-specific morphological marker of the disease.

Adult↗
PubMed1996

Mitochondrial DNA and RNA processing in MELAS.

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), a maternally inherited disorder, is usually associated with a point mutation in mitochondrial DNA (mtDNA) at position 3,243 in the tRNA Leu(UUR) gene. To further study the pathogenesis of MELAS, we analyzed tissues from 8 MELAS-3,243 patients. Southern blot analysis showed an increase in the ratio of mtDNA to nuclear DNA in almost all tissues examined, implying that mitochondrial proliferation is ubiquitous and is not confined to ragged-red fibers in muscle. By northern blot analysis, we demonstrated increased steady-state levels of RNA 19, a polycistronic transcript corresponding to the 16S rRNA + tRNA Leu(UUR) + ND1 genes (which are contiguous in the mtDNA) in heart, kidney, and muscle. These results provide further evidence that altered mitochondrial nucleic acid metabolism may have pathogenic significance in MELAS.

Adult↗
PubMed1996

Mutant GTP cyclohydrolase I mRNA levels contribute to dopa-responsive dystonia onset.

We present a new Japanese family with hereditary progressive dystonia with marked diurnal fluctuation/dopa-responsive dystonia. The affected daughter and her asymptomatic father are heterozygous for a novel missense mutation that replaces His by Pro at codon 144 in the GTP cyclohydrolase I gene. Quantitative reverse transcription-polymerase chain reaction revealed a higher ratio of mutant/normal mRNA encoding GTP cyclohydrolase I in the patient. These results demonstrate the importance of mutant mRNA levels for phenotypic variability among cases with the same mutation.

Adult↗
PubMed1996

Relationship of (CAG)nC configuration to repeat instability of the Machado-Joseph disease gene.

The mutation responsible for Machado-Joseph disease (MJD) has been identified as an expansion of a CAG trinucleotide repeat in a novel gene on chromosome 14q32.1. The CAG repeat tract is followed by C or G, and alleles are thereby divided into two types on the basis of molecular configuration, (CAG)nC and (CAG)nG. We have studied the relationship between the repeat length and the configuration in 38 patients from 28 Japanese families with MJD, and 31 unrelated normal Japanese subjects. The CAG repeat length in 100 normal alleles ranged from 13 to 37 repeats, while 38 MJD patients had one expanded allele with 64 to 84 repeats. Surprisingly, the expanded alleles had exclusively the (CAG)nC configuration, while both (CAG)nC and (CAG)nG were seen in normal alleles from MJD and control subjects. Furthermore, in normal alleles, the CAG repeat tract was significantly longer in (CAG)nC than in (CAG)nG. These findings suggest that the (CAG)nC configuration is related to repeat instability of the MJD gene.

Alleles↗
PubMed1996

Correlation between occurrence of exudative epidermitis and exfoliative toxin-producing ability of Staphylococcus hyicus.

Staphylococcus hyicus was isolated from healthy pigs and pigs affected with exudative epidermitis (EE). Thirty seven strains (P-7 to P-43) were isolated from pigs affected with EE on 8 farms while 131 strains were isolated from healthy pigs bred on 2 farms in Japan. Isolation rate for pigs affected with EE was 100% while that for healthy pigs was 35.4%. The biochemical and cultural characteristics of the isolates from healthy and diseased pigs were identical except for the Voges-Proskauer reaction. The culture supernatant of many isolates caused skin exfoliation in 1-day-old chickens. Therefore, many isolates were considered to produce S. hyicus exfoliative toxin (shET). The rate of shET production by the isolates from piglets affected with EE was 87.5%, while that of the isolates from healthy pigs was 76.1%. shETs were divided in two serotypes by immunodiffusion. Piglets experimentally infected with shET-producing and nonproducing strains were observed. Local skin erythema at the inoculation site was observed with nonproducing strains and disappeared within 48 h, while the skin erythema at the sites inoculated with shET-producing strains did not disappear until 7 days after inoculation. Typical clinical signs, such as exfoliation, exudation and crusting were observed only in the piglets inoculated with shET-producing strains.

Animals↗
PubMed1996

Contribution of lysosomes to the subcellular distribution of basic drugs in the rat liver.

PURPOSE: We examined the subcellular distribution of the basic drugs, chlorpromazine (CPZ), imipramine (IMP) and biperiden (BP), in rat liver, and evaluated the contribution of lysosome (Lys) to their intracellular distribution in comparison with that of mitochondria (Mit). METHODS: In an in vivo distribution, the concentrations of CPZ, IMP and BP in the liver subcellular fractions were determined. In an in vitro study, uptake of [3H]IMP into Lys and Mit fractions was determined in the presence or absence of several agents. RESULTS: The distribution of these drugs 10 min after administration was quite similar. However, the relative specific contents (the drug concentration per protein of each fraction divided by that of the total homogenate) in Lys were 7.3, 9.6 and 4.2, respectively for CPZ, IMP and BP, whereas those in the other organella were only 0.4 approximately 1.7. In an in vitro uptake study, the dose response of IMP uptake into Lys was biphasic, while that into Mit fractions was monophasic. The binding of IMP to the high affinity sites of Lys was pH dependent and disappeared in 50 mM NH4Cl or 50 microM CPZ, both of which increased the intralysosomal pH, the low affinity sites were not affected by these drugs. CONCLUSIONS: The results indicated that Lys has the highest affinity for the basic drugs in the liver and that its contribution to their subcellular distribution depends on the intralysosomal pH, which is also affected by these drugs. The importance of these effects may become significant in combination therapy using various basic drugs.

Animals↗
PubMed1996

Activity of intrinsic laryngeal muscles in fluent and disfluent speech.

The goal of the present experiment was to determine if stuttering is associated with unusually high levels of activity in laryngeal muscles. Qualitative and quantitative analyses of thyroarytenoid and cricothyroid recordings from 4 stuttering and 3 nonstuttering adults revealed the following: Compared to periods of fluent speech, intervals of disfluent speech are not typically characterized by higher levels of activity in these muscles; and when EMG levels during conversational speech are compared to maximal activation levels for these muscles (e.g., those observed during singing and the Valsalva maneuver), normally fluent adults show robust and sometimes near maximal recruitment during conversational speech. The adults who stutter had a lower operating range for these muscles during conversational speech, and their disfluencies did not produce relatively high activation levels. In summary, the present data require us to reject the claim that adults with a history of chronic stuttering routinely produce excessive levels of intrinsic laryngeal muscle activity. These results suggest that the use of botulinum toxin injections into the vocal folds to treat stuttering should be questioned.

Adult↗
PubMed1996

Insecticidal effects of the insect growth regulators methoprene and pyriproxyfen on the cat flea (Siphonaptera:Pulicidae).

Residual effectiveness of the insect growth regulators pyriproxyfen and methoprene against cat flea, Ctenocephalides felis (Bouché), larvae were evaluated under simulated household conditions. Pyriproxyfen provided control of larvae for > 12 mo when applied at 1 mg and 0.2 mg/m2 and > or = 3 mo at the rate of 0.04 mg/m2. Methoprene applied at 1 mg/m2 provided control for > 12 mo and 6 mo at 0.2 mg/m2. No significant mortality was observed when methoprene was applied at 0.04 mg/m2.

Animals↗
PubMed1996

Japanese triplets with cerebrotendinous xanthomatosis are homozygous for a mutant gene coding for the sterol 27-hydroxylase (Arg441Trp).

We present the first case of triplets with cerebrotendinous xanthomatosis (CTX). A C-to-T base change identified in the genomic DNA and cDNA encoding the sterol 27-hydroxylase led to replacement of arginine by tryptophan at position 441 (Arg441Trp) in the triplets. The triplets were homozygous and their mother was heterozygous for this mutant gene. The triplets exhibited an identical phenotypic expression, which was different from that of a sporadic CTX case with the same mutation.

Adult↗
PubMed1996

Decrease of the D3 dopamine receptor mRNA expression in lymphocytes from patients with Parkinson's disease.

We investigated the dopamine receptor (DAR) mRNA expression in peripheral blood lymphocytes from 45 patients with Parkinson's disease (PD) and 21 age-matched controls using the quantitative reverse transcription and polymerase chain reaction method. Beta-actin mRNA was used as an internal control to evaluate the relative expression level of the DAR mRNA. There was a statistically significant decrease of the D3 dopamine receptor (D3R) mRNA expression in PD patients compared with that in controls. There was no change in expression of the D5 dopamine reception mRNA in PD patients. A further binding study showed reduction of the D3R binding sites in PD lymphocytes. The decrease of the D3R mRNA expression correlated with the degree of clinical severity in PD patients.

Actins↗
PubMed1996

Multiple mitochondrial DNA deletions associated with autosomal recessive ophthalmoplegia and severe cardiomyopathy.

Six patients in two unrelated families from the eastern Arabian peninsula presented with childhood-onset progressive external ophthalmoplegia (PEO), mild facial and proximal limb weakness, and severe cardiomyopathy requiring cardiac transplantation. Muscle biopsies showed ragged-red and cytochrome c oxidase-negative fibers. The activities of several complexes in the electron-transport chain were decreased and Southern blot analysis showed multiple mtDNA deletions. The apparent autosomal-recessive inheritance and the association with cardiomyopathy distinguish this syndrome from autosomal-dominant PEO with multiple mtDNA deletions. The combination of autosomal-recessive PEO, cardiomyopathy, and multiple mtDNA deletions appears to be another disease due to a defect of communication between the nuclear and mitochondrial genomes.

Adolescent↗
PubMed1996

Opening of Ca(2+)-dependent K+ channels by nordihydroguaiaretic acid in porcine coronary arterial smooth muscle cells.

Effects of nordihydroguaiaretic acid (NDGA) on the Ca(2+)-dependent K+ channel (BK channel) were examined by the patch clamp technique in single smooth muscle cells of porcine coronary artery. The open probability of BK channels in inside-out patches increased by about 30 times at the holding potential of 0 mV, when 10 microM NDGA was added to the bathing solution (pCa 7.0). The effect of NDGA was concentration-dependent in the range of 1-100 microM and partly removed by washout. The enhancement of BK channels by NDGA was not observed when the cytosolic Ca2+ concentration was very low (pCa > 8.5). These results clearly indicate that NDGA possesses a BK channel opening property in coronary arterial myocytes.

Animals↗
PubMed1996

Partial deficiency of phosphoglycerate mutase with diabetic polyneuropathy: the first Japanese patient.

We report here findings in a 51-year-old Japanese man with non-insulin-dependent diabetes mellitus who complained of exercise-induced cramps. Muscle biopsy showed scattered regenerating fibers, small angular fibers and increased PAS positive particles. Electron microscopic examination revealed an abnormal accumulation of glycogen particles in subsarcolenmmal areas and between myofibrils while chemical studies showed an increased glycogen concentration and decreased phosphoglycerate mutase (PGAM), 46.9% of the normal mean value. Thus, partial PGAM deficiency, insulin resistance and mild diabetic sensory-motor polyneuropathy can induce severe cramps.

Biopsy↗
PubMed1996

[Morphological study of laryngeal ganglions and associated nerve cells in humans and five mammals].

The arrangement and numbers of intralaryngeal ganglia and associated neurons in humans and four mammals (dogs, rabbits, guinea pigs and rats) were investigated morphologically and compared with the results obtained in the cat which have been reported previously. Intralaryngeal ganglia were mostly distributed in branches of the internal branch of superior laryngeal nerve in all species, dorsal and/or dorsolateral to the posterior cricoarytenoid muscle in humans, dogs and cats and around the inferior laryngeal nerve in humans, dogs, cats, guinea pigs and rats. The total number of laryngeal ganglionic neurons was 2,000 to 2,400 in humans, 300-450 in dogs, 600-800 in cats, 250-320 in rats, and 100-150 in rabbits and guinea pigs. More than 80 percent of ganglionic neurons were present in the supraglottis in all species, except the rat, in which about 60 percent were in the subglottis. Each ganglion in all species existed within the nerve bundle, and was chiefly encapsulated with fibrous tissue, many ganglionic cells, glial cells, Schwann cells, vessels and connective tissue. The present morphological study of intralaryngeal ganglia in humans and four mammals suggests that the laryngeal ganglionic neurons have the same arrangement as in cats.

Adult↗