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Biomedical subjects

H Ono

Publications and source records attributed to H Ono.

At least 307 records · Page 17Linked to original sources
PubMed1993

4-Phenyltetrahydroisoquinoline, but not nomifensine or cocaine, inhibits methamphetamine-induced dopamine release.

The inhibitory effect of 4-phenyltetrahydroisoquinoline (4-PTIQ) on methamphetamine-induced dopamine release in the rat nucleus accumbens was investigated using a brain microdialysis method. Methamphetamine (10(-6) M) infusion through a microdialysis probe induced the release of dopamine. Although the uptake inhibitors, cocaine (3 x 10(-6) M) and nomifensine (10(-6) M), failed to block dopamine release, 4-PTIQ (10(-6 M) inhibited the dopamine-releasing effect of methamphetamine. 4-PTIQ did not affect the elevation of the extracellular dopamine level induced by high concentrations of nomifensine (10(-5) M) and cocaine (3 x 10(-5) M). 4-PTIQ was the weakest inhibitor of [3H]dopamine uptake by rat striatal synaptosomes. These results suggest that 4-PTIQ is a selective antagonist against the dopamine-releasing effect of methamphetamine in the nucleus accumbens.

Animals↗
PubMed1993

Extensive MHC variability in cichlid fishes of Lake Malawi.

Lake Malawi in East Africa harbours 500-1,000 endemic species of cichlid fishes, all presumably derived by adaptive radiation from a single founding population within the past two million years. The species of this 'flock' differ strikingly in their ecology and behaviour, moderately in their external morphology and very little in their molecular characteristics. Here we describe high sequence variability of class II major histocompatibility complex genes in a sample of species from Lake Malawi. The variability provides a set of molecular markers for studying adaptive radiation and should be useful for estimating the size of the population that founded the species flock.

Africa, Southern↗
PubMed1993

Transport of prepro-albumin into inverted vesicles prepared from the inner membrane of rat liver mitochondria.

When inverted vesicles prepared from the inner membrane of rat liver mitochondria were incubated with prepro-rat serum albumin, considerable amounts of prepro-albumin and pro-albumin were recovered with the inverted vesicles re-isolated by centrifugation. Pro-albumin was resistant to trypsin, but prepro-albumin was completely digested by trypsin, indicating that prepro-albumin was transported into the vesicles and concomitantly converted to pro-albumin. This transport process required ATP, but not a membrane potential. These results suggest that some export machinery for a protein having an amino acid sequence in its N-terminal portion similar to the signal sequence of secretory protein exists in the inner mitochondrial membrane.

Adenosine Triphosphate↗
PubMed1993

Vascular complications of vascularized composite tissue transfer: outcome and salvage techniques.

Two hundred fifty-two vascularized composite tissue transfers were performed from 1985 to 1992 at Nara Medical University Hospital. Free tissue transfers were performed in 185 patients and island tissue transfers in 67 patients. Of these, 39 flaps were reexplored because of vascular complications. On initial reexploration, vascular obstruction was found at the site of anastomosis or in the main vascular pedicle in 36 patients and in the perforating vessels to the monitor flap in three patients. Arterial thrombus occurred in 11 patients, venous thrombosis in 12, and both in nine. Twenty-five reexplored flaps were salvaged. Initially, heparin was administered systemically when vascular compromise was suspected intraoperatively or postoperatively. Recently, we have used a "continuous local heparinization" technique to minimize blood loss. This method has been used in 12 patients who underwent reexploration and in nine patients in whom vascular compromise was suspected. Nineteen flaps survived completely, and two flaps failed.

Adolescent↗
PubMed1993

Exon-intron organization of fish major histocompatibility complex class II B genes.

Major histocompatibility complex (Mhc) molecules bind self and foreign peptides and present them to lymphocytes for recognition. Activation of lymphocytes by Mhc-bound foreign peptides leads to specific immune response against parasites. The Mhc genes have been studied extensively in mammals and birds but much less in other vertebrate classes. In this communication we provide the first description of the exon-intron organization of class II beta-chain-encoding genes from the teleost fish Aulonocara hansbaenschi, family Cichlidae. Each of the genes consists of six exons, E1 through E6, encoding the leader peptide (E1), beta 1 domain (E1+E2), beta 2 domain (E3+E4), connecting peptide (E5), transmembrane region (E5), cytoplasmic domain (E5+E6), and the 3' untranslated region (E6). The exons are separated by relatively short introns, the length of the longest intron being 1.3 kilobase pairs. An important difference between these and all other known class II B genes is that the beta 2 domain-encoding exon is split by an intron 97 base pairs in length. The intron is absent in other teleost fishes such as Brachydanio rerio. A change in the 3' splice site of intron 4 in some of the genes of A. hansbaenschi and of another cichlid fish, Cyphotilapia frontosa, has produced two extra codons at the 5' end of exon 5. Comparison of the A. hansbaenschi coding sequences with those of C. frontosa has revealed a concentration of variability in exon 2 and part of exon 3. Taken together, these observations provide evidence for the existence in cichlid fishes of at least two class II B loci which are functionally equivalent to the corresponding loci in mammals. The exon-intron organization and sequence similarities indicate that the two loci arose by duplication from a common ancestral gene.

Amino Acid Sequence↗
PubMed1993

Cloning of the beta 2-microglobulin gene in the zebrafish.

The beta 2-microglobulin (beta 2m) is a protein found in the serum in a free form and on the cell surface in a form noncovalently associated with the alpha chain of the class I major histocompatibility complex (Mhc) molecules. In mammals, the beta 2m-encoding gene (B2m) is found on a chromosome different from the Mhc proper. We have isolated and characterized the B2m gene of the zebrafish, Brachydanio rerio, family Cyprinidae. We obtained both cDNA and genomic clones of the Brre-B2m gene. The cDNA clones contained the entire coding sequence, the entire 3' untranslated (UT) region, and at least part of the 5'UT region. The genomic clone contained the entire Brre-B2m gene. The coding sequence specifies 97 amino acid residues of the mature protein so that the zebrafish beta 2m is two residues shorter than human and one residue shorter than cattle, fowl, or turkey beta 2m (codons at positions 85 and 86 have been deleted in the Brre-B2m gene). The amino acid and nucleotide sequence similarities between zebrafish and human beta 2m (B2m) are 45% and 59%, respectively. Approximately 24% of the positions are invariant and an additional 9% show only conservative substitutions in comparisons which include all known beta 2m sequences (fish, avian, and mammalian). Most of the conserved positions are in the beta strands (some 47% of the beta-strand positions are conserved in the three vertebrate classes). The Brre-B2m gene consists of four exons separated by three introns. All of the introns are considerably shorter than the corresponding introns in the mammalian B2m genes. The coding sequences of the cDNA and the genomic clones are almost identical but the sequences of the 3'UT regions differ at 1.7% of the sites, suggesting that the genes borne by these clones might have diverged at least 0.7 million years (my) ago. In contrast to the human B2m gene, the Brre-B2m gene shows no bias in the distribution of the CpG dinucleotides: the dinucleotides are distributed evenly along the entire available sequence. The haploid genome of the zebrafish contains only one copy of the B2m gene.

Amino Acid Sequence↗
PubMed1993

Detection of collagenase mRNA in odontoclasts of bovine root-resorbing tissue by in situ hybridization.

The odontoclast, which is morphologically similar to osteoclast, is thought to play a major role in root resorption of deciduous teeth. High collagenolytic activity has been detected in the root resorbing tissue. In order to identify collagenase-producing cells and the role of collagenase in root resorption of deciduous tooth, in situ hybridization of collagenase mRNA in bovine root-resorbing tissue sections was performed using a digoxigenin-labeled, nonradioactive RNA probe. Collagenase mRNA expression was clearly observed in odontoclasts in addition to the macrophages, fibroblasts, odontoblasts, and cementoblasts. Multinuclear odontoclasts showed intense tartrate-resistant acid phosphatase (TRAP) activity. We also examined interleukin-1 (IL-1) mRNA expression in the root-resorbing tissue by in situ hybridization. IL-1 transcripts were found to be expressed in odontoclasts, fibroblasts, and macrophages suggesting that IL-1 might be an important factor for promoting root resorption. These results suggest that the collagenase produced by odontoclasts may play a key role in dentin collagen degradation in root resorption.

Acid Phosphatase↗
PubMed1993

Non-radioactive coloured microsphere measurement of regional tissue blood flow for axial pattern flaps in rabbits.

We administered non-radioactive coloured microspheres (NRACM) to measure the regional tissue blood flow (RTBF) of eight axial pattern flaps and four kidneys in four rabbits using four repeated injections into each animal. As a control, we used radioactive microspheres (RAM) for six kidneys in three rabbits. There were no significant differences for RTBF values between NRACM and RAM, between the numbers of microspheres used (2 x 10(6) and 4 x 10(6)), or between the number of injections. These results showed that NRACM is a useful and safe laboratory method.

Animals↗
PubMed1993

Blood flow through prefabricated flaps--an experimental study in rabbits.

Prefabricated flaps were created by femoral vessel implantation beneath the abdominal skin in rabbits. The area of survival and blood flow through the prefabricated flap were measured after 1, 2, 4, 6, 8, and 12-week intervals. The parameters at 6, 8 and 12-week intervals were significantly larger than those for random pattern flaps (p < 0.01), but were significantly smaller than those for axial pattern flaps (p < 0.01). The minimum interval at which the prefabricated flap could be transferred successfully was between 6 and 8 weeks in this model. Microangiography demonstrated that neovascularisation began at the distal end of the implanted vascular bundle and spread throughout the flap by 8 weeks.

Abdominal Muscles↗
PubMed1993

Effect of 4-phenyl-1,2,3,4-tetrahydroisoquinoline on ambulation induced by injection of methamphetamine into the nucleus accumbens in rats.

4-Phenyl-1,2,3,4-tetrahydroisoquinoline (4-PTIQ) has previously been shown to have antagonistic properties to methamphetamine in the spinal cord. Administration of 4-PTIQ (5 mg/kg, s.c.) reduced the ambulation induced by methamphetamine (0.5 mg/kg, s.c.) in rats. Methamphetamine (3 micrograms), injected unilaterally into the nucleus accumbens, increased ambulation. Alone, 4-PTIQ (10 micrograms) failed to elicit ambulation; however, it inhibited the methamphetamine-induced increase in ambulation. The alpha 1-antagonist prazosin (0.5 micrograms) or the beta-antagonist propranolol (3 micrograms) showed no effect on ambulation induced by methamphetamine. Haloperidol (5 ng), which possesses strong dopamine-blocking activity, abolished the ambulation induced by methamphetamine. The drug 4-PTIQ had weak affinity for dopamine D1 and D2 receptors. These results support the possibility that the inhibitory effects of 4-PTIQ on the ambulation-stimulating effects of methamphetamine, are due to blocking of the dopamine-releasing effect of methamphetamine but not due to dopamine blocking effects.

Animals↗
PubMed1993

Inhibitory effect of 4-phenyltetrahydroisoquinoline on locomotion and dopamine release induced by micro-injection of methamphetamine into the nucleus accumbens of the rat.

The inhibitory effects of 4-phenyl-1,2,3,4-tetrahydroisoquinoline (4-PTIQ) on methamphetamine-induced increases in dopamine and locomotion were investigated. Methamphetamine hydrochloride (10 micrograms) microinjected into the nucleus accumbens increased both locomotor activity and extracellular dopamine levels, measured by the brain microdialysis method. 4-PTIQ hydrochloride (20 micrograms) co-injected with methamphetamine inhibited both the increase in dopamine and the locomotor activity. The uptake blocker cocaine hydrochloride (20 micrograms) co-injected with methamphetamine failed to inhibit the effect of methamphetamine. Thus 4-PTIQ but not cocaine inhibited the dopamine-releasing effect of methamphetamine, and 4-PTIQ is suggested to block methamphetamine-induced locomotion by inhibition of dopamine release.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1993

Depression of the monosynaptic reflex by apomorphine or bromocriptine is not mediated by D1/D2 receptors.

The role of dopamine in spinal motor transmission was investigated using spinal reflexes in acutely spinalized rats. Intravenous administration of a relatively high dose of the dopamine receptor agonist apomorphine-HCl (3 mg/kg) or the D2 receptor agonist bromocriptine mesylate (1 mg/kg) reduced the amplitude of the monosynaptic reflex (MSR). Depression of the MSR by both drugs was antagonized by haloperidol (1 mg/kg), but not by the D2 receptor antagonists YM-09151-2 (0.2 mg/kg) and sulpiride (10 mg/kg), or by a combination of the D1 receptor antagonist SKF 83566 (0.01 mg/kg) and sulpiride (10 mg/kg). Intravenous administration of the selective D1 receptor agonist SKF 77434 (0.1 and 1 mg/kg) and the D2/D3 receptor agonist quinpirole-HCl (0.1 and 1 mg/kg) had no significant effect on the MSR. Simultaneous administration of SKF 77434 and quinpirole had no significant effect on the MSR. These results show that stimulation of D1/D2 receptors has little influence on the MSR, and suggest that descending dopaminergic systems mediating these receptors have little influence on MSR transmission. Apomorphine and bromocriptine may inhibit the MSR via other subtypes of D1/D2 or other, as yet undiscovered, dopamine receptors or via non-dopaminergic mechanisms.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1993

Electrophysiological comparison of the effects of MCI-154 on smooth muscles between mesenteric artery and vein of dogs.

1. Effects of MCI-154, a cardiotonic vasodilator, on smooth muscles were compared in isolated mesenteric artery and vein of dog. 2. MCI-154 depolarized the membrane, and inhibited Ca(2+)- and K(+)-contractions more in the vein than in the artery. 3. Nerve-mediated and noradrenaline-induced contractions, and the excitatory junction potential (e.j.p.) were inhibited by MCI-154 in the vein and potentiated in the artery. 4. Compound action potentials of perivascular nerves and action potentials generated on the e.j.p. were not altered by MCI-154. 5. MCI-154 predominantly dilates venous muscles, and as a result would reduce cardiac outflow and lower systemic blood pressure.

Animals↗
PubMed1993

Malignant osteopetrosis treated with high doses of 1 alpha-hydroxyvitamin D3 and interferon gamma.

A male infant with malignant osteopetrosis was treated with high doses of 1 alpha-hydroxyvitamin D3 and interferon gamma. Therapy with 1 alpha-hydroxyvitamin D3 increased the serum calcium level despite the markedly elevated serum level of 1 alpha, 25-dihydroxyvitamin D before treatment. Recombinant human interferon gamma increased neither the bone mineral nor matrix turnover, and was not tolerated because of bone marrow suppression.

Dose-Response Relationship, Drug↗
PubMed1993

Major-histocompatibility-complex variation in two species of cichlid fishes from Lake Malawi.

Lake Malawi in eastern Africa harbors > 500 endemic species of cichlid fishes, all of which are believed to have emerged from a single founding population in the past 2 Myr. Molecular characterization of differences among the species could provide important information about the nature of speciation in the period of adaptive radiation. Because of the close relationship, however, molecular variation among the species has been difficult to ascertain. In this communication, we provide evidence for extensive differences, in major-histocompatibility-complex (Mhc) class II genes, between two related species, Pseudotropheus zebra and Melanochromis auratus. We used specific primers to amplify and sequence intron 1 and exon 2 of the class II genes from 18 individuals. Although we found 20 different sequences among the 42 that we produced, there was not a single sequence shared by the two species. Thus the study suggests that different cichlid species of Lake Malawi have different profiles of class II alleles, presumably because the polymorphism present in the ancestral founding population segregated differentially into the various species. These results make Mhc genes an important tool for elucidating speciation.

Amino Acid Sequence↗