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H Usui

Publications and source records attributed to H Usui.

At least 91 records · Page 5Linked to original sources
PubMed1993

Somatostatin-induced contraction mediated by endothelial TXA2 production in canine cerebral arteries.

Whether somatostatin causes endothelium-dependent contraction (EDC) in isolated canine basilar arteries was examined. Somatostatin (10(-8)-10(-6) M) caused transient contractions in a dose-dependent manner. These contractions were abolished by removal of the endothelium, while the contractile response to neuropeptide Y occurred even after removal of the endothelium. The EDC induced by somatostatin (10(-7) M) was affected by neither atropine (10(-6) M) nor cyclo-somatostatin (10(-5) M), which suggests that the EDC is not due to release of endogenous acetylcholine and that the endothelial somatostatin receptor is different from hormonal somatostatin receptors. The somatostatin-induced EDC was attenuated by cyclooxygenase inhibitors (aspirin and indomethacin), thromboxane A2 (TXA2) synthetase inhibitors (OKY-064 and RS-5186), and TXA2 antagonists (ONO-3708 and S-145), which suggests that the endothelium-derived contracting factor is TXA2. These findings demonstrate that somatostatin causes EDC via activation of TXA2 synthesis in canine cerebral arteries.

Animals↗
PubMed1993

Neuron-specific enolase (NSE) and non-neuronal enolase (NNE) mRNAs are co-expressed in neurons of the rat cerebellum: in situ hybridization histochemistry.

Using in situ hybridization histochemistry, we analysed the localization of mRNAs for neuron-specific enolase (NSE) and non-neuronal enolase (NNE) in the rat cerebellum at various postnatal developmental stages. Synthetic 45 meric oligonucleotides corresponding to partial sequences of the non-coding region of rat NSE or NNE mRNA were 35S-labeled to approximately the same specific activity and used as hybridization probes. On examination of the adult rat cerebellum, both NSE and NNE signals were detected in all identified and presumed neurons which included Purkinje cells, internal granule cells and presumed stellate/basket cells in the cerebellar cortex and neurons of the dentate nucleus. Examination of the cerebellum during postnatal development also revealed coexistence of NSE and NNE signals in these neurons from early stages. During development, both signals coincidentally increased in Purkinje cells and neurons of the dentate nucleus, while only NSE signals showed a gradual increase in the internal granule cells in which NNE signals remained at the same level from early postnatal to adult stages. The external granule cells showed NNE signals until postnatal day 7 but thereafter the signals became less distinct, especially in cells if the inner zone of the external granule cell layer. Thus, it was shown that NSE and NNE were commonly coexpressed at the mRNA level in various neurons of the cerebellum except for very undifferentiated external granule cells which expressed only NNE mRNA.

Aging↗
PubMed1993

Effect of body characteristics on the variables of signal-averaged electrocardiogram in healthy teenage subjects.

Ventricular late potentials are obtained by signal-averaged surface electrocardiography. Late potentials have been reported to be affected by body characteristics or left ventricular mass. To evaluate late potentials in relation to body characteristics, 52 healthy Japanese young volunteers (21 girls, 31 boys) aged 15-16 years were studied. QRS duration in men was significantly longer than in women. There were no significant differences in low-amplitude signal and root mean square voltage between women and men. When relations between signal-averaged electrocardiographic parameters and body characteristics were examined, QRS duration had positive linear correlations with weight and body mass index. The slope of QRS duration and weight relation, and QRS duration and body mass index relation was significantly steeper in men compared to those in women; a prolongation of QRS duration in men compared to women as weight and body mass index increased. Our results indicated that QRS duration in teenage healthy subjects should be used with caution because it is affected by gender.

Adolescent↗
PubMed1993

[Maxillary prosthesis for better QOL--analysis of maxillary prosthesis stability].

We report here an analysis of 100 cases of maxillary prosthesis, experienced from July, 1981 through June, 1989, with special reference to stability. Sixty-four percent of prostheses were partial denture type and complete denture type comprised thirty-two percent. Eighty-six percent of cases were estimated to have defects exceeding 2/6 and 3/6 of the surface width of the palate. Ninety percent of prostheses weighed less than 15 gm. The stability of these prostheses was estimated to be good in 85% of cases, the stability of the denture type being good in 95% of partial denture type cases, and 62% of complete denture type cases. According to type distinctions among maxillary defects as a whole, in the smaller 1/6 and 2/6 defect cases, good stability can be expected, and in 3/6 and 4/6 defect cases, 80% achieve good stability. According to prosthesis weight, 80% of those weighing less than 15 gm were considered to have shown good stability. Thus, these maxillary prostheses can remain in place and functional ameliorating disability and contributing to the patient's quality of life.

Adult↗
PubMed1992

Human glial fibrillary acidic protein (GFAP): molecular cloning of the complete cDNA sequence and chromosomal localization (chromosome 17) of the GFAP gene.

We isolated three glial fibrillary acidic protein (GFAP) cDNA clones from a glioma cell line, U-251 MG. One clone isolated from a U-251 MG cDNA library was long, but lacked both ends. Using poly(A)+ RNA and primers synthesized according to the sequence of this clone, we used the polymerase chain reaction-assisted rapid amplification of cDNA ends (PCR-RACE) method, which is a strategy to isolate cDNA ends, and obtained cDNA clones for the 5' and 3' ends. From the sequences of these overlapping clones, the complete nucleotide sequence of human GFAP cDNA was established. The start (ATG) and the stop (TGA) signals were seen at nucleotide positions 15 and 1311, respectively, and divided the entire sequence of 3027 bp into 14 bp of 5' non-coding, 1296 bp of coding and 1717 bp of 3' non-coding regions. Using cDNA probes made from both the coding and the 3' non-coding regions, Northern blot hybridization was performed with two different stringencies on RNAs from human and rodent brains and human GFAP-positive and -negative cells. It was shown that the 3' non-coding region probe was more specific for human GFAP than the coding region probe which was specific only under higher stringency conditions. This was also suggested by homology analysis of the sequence with those of various intermediate filament proteins. Based on these findings, we performed spot blot hybridization of sorted human chromosomes and Southern blot hybridization of PCR-amplified DNAs of a panel of hamster-human somatic cell hybrids and localized the human GFAP gene to chromosome 17.

Amino Acid Sequence↗
PubMed1992

Nifedipine-resistant Ca(++)-induced contraction in tail artery of spontaneously hypertensive rats.

Nifedipine-resistant Ca(++)-induced contractions (NR-Ca(++)-contraction) were compared in the tail arteries from SHRs and WKYs (5 and 13 week old). NR-Ca(++)-contraction of tail artery was defined as follows: Ca(++)-induced contraction in the presence of norepinephrine (NE) (10(-5) M) or 5-hydroxytryptamine (5-HT) (10(-5) M) in Ca(++)-free medium containing EGTA (0.1 mM) and nifedipine (10(-6) M). NR-Ca(++)-contractions in arteries from 5 week old SHRs and WKYs were not different. In contrast, NR-Ca(++)-contractions in arteries from 13 week old SHRs were about 2-fold greater than in arteries from 13 week old WKYs. In arteries from 13 week old WKYs and SHRs, nitroglycerin (10(-5) M) significantly reduced the NR-Ca(++)-contraction in the presence of 5-HT but not in the presence of NE. The reduction was inhibited by the presence of methylene blue (3 x 10(-6) M). 8-Bromo-cGMP (10(-4) M) reduced significantly the NR-Ca(++)-contraction in the presence of 5-HT in arteries from 13 week old SHRs and WKYs. The present experiments clearly demonstrated that the NR-Ca(++)-contractions (both in the presence of NE and 5-HT) in 13 week old SHRs were significantly greater than those in arteries from 13 week old WKYs. These results suggest that in addition to an increase in voltage-operated Ca++ mobilization reported by others, an increase in NR-Ca++ mobilization may contribute to the development of hypertension in SHR.

Animals↗
PubMed1992

Structure and expression of human and rat D2 dopamine receptor genes.

D2 dopamine receptor may be related with the pathogenesis of Parkinson's disease and schizophrenia. Furthermore, the antipsychotic drugs have high affinity for D2 dopamine receptor. We carried out the cloning of the genomic DNA for human D2 dopamine receptor and clarified the structure of this gene. Our isolated gene spans about 15 kbp and consists of seven exons interrupted by six introns. However, putative first exon was not yet identified. Spot blot hybridization analysis of cell sorter fractionated human chromosomal DNA with D2 receptor genomic DNA revealed the localization of this gene in the chromosome 11 fraction. We analyzed human genomic DNA by Southern blot hybridization with D2 dopamine receptor genomic DNA as a probe, but so far we could not find RFLP. Northern blot analyses of brain RNA of several animals and rat brain RNA after various treatments were carried out. Developmental changes of D2 dopamine receptor mRNA were observed in the rat brains.

Aging↗
PubMed1992

Syntheses and 5-HT2 antagonist activity of bicyclic 1,2,4-triazol-3(2H)-one and 1,3,5-triazine-2,4(3H)-dione derivatives.

A series of bicyclic 1,2,4-triazol-3(2H)-one and 1,3,5-triazine-2,4(3H)-dione derivatives with a 4-[bis(4-fluoro-phenyl)methylene]piperidine or 4-(4-fluorobenzoyl)piperidine group has been prepared and tested for 5-HT2 and alpha 1 receptor antagonist activity. Among the compounds prepared, 2-[2-[4-[bis(4-fluorophenyl)methylene]-piperidin-1-yl]ethyl]- 5,6,7,8-tetrahydro-1,2,4-triazolo[4,3-a]pyridin-3(2H)-one (7b) had the most potent 5-HT2 antagonist activity, which was greater than ritanserin (2), while 7b did not show alpha 1 antagonist activity in vivo. The central 5-HT2 receptor antagonism was approximately 1/30 that of 2 when tested for the ability to block head twitches induced by 5-hydroxytryptophan. Compound 21b, 3-[2-[4-(4-fluorobenzoyl)piperidin-1-yl]ethyl]-6,7,8,9-tetrahydro- 2H- pyrido[1,2-a]-1,3,5-triazine-2,4(3H)-dione also displayed potent 5-HT2 antagonist activity. The compound had moderate alpha 1 receptor antagonism, and the potency inhibiting head twitches was about one-third that of ketanserin (1). These results indicate that 5,6,7,8-tetrahydro-1,2,4-triazolo[4,3-a]pyrimidin-3(2H)-one and 6,7,8,9-tetrahydro-2H-pyrido-[1,2-a]-1,3,5-triazine-2,4(3H)-dione ring systems are useful components of 5-HT2 antagonists.

Animals↗
PubMed1992

Purification and characterization of a possible protooncogene fyn product, p59fyn, from a rat brain particulate fraction.

Four tyrosine-protein kinases that reacted with antibodies specific to p62c-yes, p60c-src, p60c-src+, and p59fyn, respectively, were solubilized from a rat brain particulate fraction and separated by casein-Toyopearl column chromatography. Possible p59fyn, with a pI of 6.5, was purified 490-fold as a single 59-kDa protein band on SDS-PAGE. The purified enzyme contained almost no phosphotyrosine residues but was autophosphorylated with Mg2+. ATP exclusively at tyrosine residues, with a concomitant increase in the kinase activity toward tyrosine-glutamate (1:4) copolymers. The rate of the copolymer phosphorylation was proportional to the square of the enzyme concentration, suggesting activation through intermolecular catalysis. In the presence of Mn2+, however, the reaction showed a first-order dependence on the enzyme concentration.

Animals↗
PubMed1992

Endothelium-dependent contraction produced by acetylcholine and relaxation produced by histamine in monkey basilar arteries.

The present experiments were carried out to investigate the endothelium dependence of the responses to acetylcholine (ACh), arachidonic acid, and histamine in monkey basilar arteries. ACh and arachidonic acid caused endothelium-dependent contraction (EC) in both monkey and canine basilar arteries. The endothelium-derived contracting factor (EDCF) was probably thromboxane A2 (TxA2), as the EDC was attenuated by a cyclooxygenase inhibitor, TxA2 synthetase inhibitors, and TxA2 antagonists. On the other hand, histamine caused endothelium-dependent relaxation (EDR) in monkey and EDC in canine basilar arteries. The EDR in monkey basilar arteries was attenuated by a nitric oxide synthase inhibitor. The EDR and EDC were antagonized by tripelennamine but not by cimetidine, indicating that they are mediated by H1-receptors. From these results, we suggest that in the monkey basilar artery, either there are two types of endothelium (an EDCF type for ACh and arachidonic acid and an EDRF type for histamine) or there is a single type of endothelium with two types of signalling processes (one for EDC and one for EDR).

Acetylcholine↗
PubMed1992

Transcription of the rat cholecystokinin gene is initiated at multiple sites: verification by an in vitro transcription system.

The cDNA that accommodates the most distal 5'-end region of cholecystokinin mRNA was isolated from an internally primed cDNA library. Using primer extension and S1 nuclease protection analyses, we demonstrated multiple RNA molecules generated from the rat cholecystokinin gene, a single-copy sequence. The longest RNA is transcribed at position--225 upstream relative to the translation start site. The major transcription, more than 95% of the total cholecystokinin mRNA in rat brain, occurred at--59 and its promoter activity was determined by in vitro RNA synthesis in a HeLa cell extract. Deletion to--105 demonstrated an approximately 60% decrease in transcriptional level compared with the full promoter activity. At least the upstream region between--254 and--105 is necessary for transcription initiated at--59 of the cholecystokinin gene by the cell-free system.

Animals↗
PubMed1992

Relaxant response of isolated basilar arteries to calcitonin gene-related peptide in stroke-prone spontaneously hypertensive rats.

The relaxant effects of calcitonin gene-related peptide (CGRP) and other drugs were compared in basilar artery rings obtained from stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto rats (WKY). In addition, the relaxant effect of CGRP on basilar arteries from spontaneously hypertensive rats (SHR) was examined. Relaxation induced by CGRP was independent of the presence of endothelium, and it was markedly increased in SHRSP when compared to WKY. In contrast, acetylcholine-induced relaxation was endothelium-dependent and did not differ between the two groups. Enhanced CGRP-induced relaxation was also found in SHR when compared to WKY. However, the relaxant response was greater in SHRSP than in SHR. No significant differences were found in the relaxation induced by isoproterenol, forskolin, dibutyryl cyclic AMP, and 3-isobutyl-1-methylxanthine in endothelium-rubbed arteries of WKY and SHRSP. These results suggest that CGRP produces endothelium-independent relaxation in the rat basilar artery, and that the enhanced CGRP-induced relaxation found in SHRSP may not be associated with alterations of vasodilation mediated by cyclic AMP.

1-Methyl-3-isobutylxanthine↗
PubMed1992

[Clinical pathology of hypopharyngeal cancer--comparison between TN and pTN].

Seventy patients with the hypopharyngeal cancer who underwent pharyngolaryngoesophagectomy with bilateral neck dissection between 1978 and 1990 were examined retrospectively to compare TN and pTN in these patients and clarify the clinical pathology of the hypopharyngeal cancer. Among the 70 cases of hypopharyngeal cancer, there were 46 cases of piriformis sinus cancer (PSC) and 24 cases of postcricoid cancer (PCC). The pathological diagnosis of all these cases was squamous cell carcinoma (SCC). The following results were obtained: 1. Invasion of the thyroid gland was seen in 8 cases of PCC (33.3%) and 6 cases of PSC (13.0%). The thyroid gland can be preserved in PSC, whereas its removal is indicated in PCC. 2. Twenty-nine cases of N0 necks proved to be pN0-2b in 27 cases (93.1%) which may be controlled by homolateral neck dissection, and pN2c in 2 cases (6.9%), which requires bilateral neck dissection. On the other hand, 29 cases of N1-2b necks which represent one-sided neck metastasis were pN0-2b in 15 cases (51.7%) and pN2c in 14 cases (48.3%). These results demonstrate that N0 necks can, in the majority of cases, be controlled by homolateral neck dissection alone but that N1-2b necks require bilateral neck dissection. 3. Occult neck metastases were observed in PCC more often than in PSC, because paratracheal metastases of PCC were difficult to expose before surgery. 4. Pathological neck metastases of both PSC and PCC were most commonly situated in the superior and middle internal jugular nodes. Paratracheal metastases of PCC was found pathologically in 10 cases (41.7%). Paratracheal nodes must be dissected meticulously during the resection of PCC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗