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J Kurihara

Publications and source records attributed to J Kurihara.

At least 19 recordsLinked to original sources
PubMed2003

FK506 attenuates the post-ischemic perturbation of protein kinases and tyrosine phosphorylation in the gerbil hippocampal CA1 sectors.

To explore effects of Immunosuppressant FK506 on signal transduction pathway. we studied changes in subcellular distribution of protein kinase Cgamma (PKCgamma), CaM kinase II (CaMKII), as well as changes of tyrosine phosphorylation levels after ischemia. Male Mongolian gerbils were divided into 3 groups; FK506 (1 mg/kg, 3 mg/kg) and vehicle. FK506 was administered intravenously after 5 min ischemia. At the designated time points (0 time, 5 min ischemia, 1 hour, or 24 hour recovery), heads were frozen and samples were taken from CAI subfield of hippocampus. Western blot analysis was carried out with specific antibodies for PKCgamma, CaMKII, and phosphotyrosine. FK506 administration significantly decreased translocation of PKCgamma and CaMKII at 24 h of recovery (p < 0.05, ANOVA followed by Student-Newman Keuls' test) in P2 fraction. The levels of tyrosine phosphorylated p160, p140, p100, p90, and p80 in P2 fraction were also significantly decreased with FK506 treatment at 24 h of recovery. The persistently elevated PKCgamma and CaMKII level in P2 fraction which may be related to cell death, are attenuated with FK506 treatment. FK506 may contribute to recover calcium homeostasis in the post ischemic phase and promote cell survival.

Animals↗
PubMed2001

Comparative analysis of the Band 4.1/ezrin-related protein tyrosine phosphatase Pez from two Drosophila species: implications for structure and function.

The FERM-PTPs are a group of proteins that have FERM (Band 4.1, ezrin, radixin, moesin homology) domains at or near their N-termini, and PTP (protein tyrosine phosphatase) domains at their C-termini. Their central regions contain either PSD-95, Dlg, ZO-1 homology domains or putative Src homology 3 domain binding sites. The known FERM-PTPs fall into three distinct classes, which we name BAS, MEG, and PEZ, after representative human PTPs. Here we analyze Pez, a novel gene encoding the single PEZ-class protein present in Drosophila. Pez cDNAs were sequenced from the distantly related flies Drosophila melanogaster and Drosophila silvestris, and found to be highly conserved except in the central region, which contains at least 21 insertions and deletions. Comparison of fly and human Pez reveals several short conserved motifs in the central region that are likely protein binding sites and/or phosphorylation sites. We also identified novel invertebrate members of the BAS and MEG classes using genome data, and generated an alignment of vertebrate and invertebrate FERM domains of each class. 'Specialized' residues were identified that are conserved only within a given class of PTPs. These residues highlight surface regions that may bind class-specific ligands; for PEZ, these residues cluster on and near FERM subdomain F1. Finally, the PTP domain of fly Pez was modeled based on known PTP tertiary structures, and we conclude that Pez is likely a functional phosphatase despite some unusual features of the active site cleft sequences. Biochemical confirmation of this hypothesis and genetic analysis of Pez are currently underway.

Amino Acid Sequence↗
PubMed2001

KT3-671, an angiotensin AT1 receptor antagonist, attenuates vascular but not cardiac responses to sympathetic nerve stimulation in pithed rats.

Effects of KT3-671 on vascular and cardiac sympathetic neurotransmission were investigated in pithed rats. The pressor response to spinal stimulation (5 Hz) of the pithed rat without the adrenals was approximately 75% of that with the adrenals. Guanethidine (8 mg/kg, i.v.) decreased by about 76% the pressor response to sympathetic stimulation in the pithed rat with intact adrenals and the guanethidine-resistant response was almost completely abolished by bilateral adrenalectomy. Therefore, the following experiments were done using the pithed rat without the adrenals. KT3-671 (1-10 mg/kg, i.v.) as well as losartan (1-10 mg/kg, i.v.) inhibited dose-dependently the pressor response to sympathetic stimulation. KT3-671 was approximately four times more potent than losartan in inhibiting the pressor response. The two angiotensin II subtype 1 receptor antagonists (10 mg/kg, i.v.) did not affect the pressor response to exogenously administered norepinephrine. Neither KT3-671 nor losartan influenced the tachycardia induced by spinal stimulation and isoprenaline. Intravenous infusion of angiotensin II (100 ng/kg/min) did not affect both pressor and tachycardic responses to sympathetic stimulation. In conclusion, KT3-671 as well as losartan inhibits vascular but not cardiac sympathetic neurotransmission of the pithed rats, which may contribute to its overall antihypertensive efficacy.

Adrenalectomy↗
PubMed2001

Mutations in the novel membrane protein spinster interfere with programmed cell death and cause neural degeneration in Drosophila melanogaster.

Mutations in the spin gene are characterized by an extraordinarily strong rejection behavior of female flies in response to male courtship. They are also accompanied by decreases in the viability, adult life span, and oviposition rate of the flies. In spin mutants, some oocytes and adult neural cells undergo degeneration, which is preceded by reductions in programmed cell death of nurse cells in ovaries and of neurons in the pupal nervous system, respectively. The central nervous system (CNS) of spin mutant flies accumulates autofluorescent lipopigments with characteristics similar to those of lipofuscin. The spin locus generates at least five different transcripts, with only two of these being able to rescue the spin behavioral phenotype; each encodes a protein with multiple membrane-spanning domains that are expressed in both the surface glial cells in the CNS and the follicle cells in the ovaries. Orthologs of the spin gene have also been identified in a number of species from nematodes to humans. Analysis of the spin mutant will give us new insights into neurodegenerative diseases and aging.

Amino Acid Sequence↗
PubMed2001

Ischemic pre-conditioning affects the subcellular distribution of protein kinase C and calcium/calmodulin-dependent protein kinase II in the gerbil hippocampal CA1 neurons.

Brief ischemic episode, which in itself is not lethal, confers tolerance to subsequent ischemic insults. Since intracellular signal transduction system has been implicated in ischemic cell death, we studied the effect of pre-conditioning on the changes in the subcellular distribution of protein kinase Cgamma (PKCgamma) as well as CaM kinase II (CaMKII). Gerbils were pre-conditioned by a sublethal 2 min cerebral ischemia 24 h prior to lethal 5 min ischemia. The pre-conditioning generally downregulated PKCgamma and CaMKII in the CA1 hippocampus. Especially at the starting point of the second lethal ischemia, the cytosolic PKCgamma level was about 40% lower in the pre-conditioned group. Also, the crude synaptosomal CaMKII level at 24 h reperfusion following the second ischemia was significantly lower in the pre-conditioned group, showing enhanced recovery of CaMKII translocation. Present results suggest that ischemic pre-conditioning may downregulate calcium-mediated cell signaling system, enhancing normalization of calcium homeostasis, perturbed by the second ischemia of lethal duration.

Animals↗
PubMed2001

2-Arachidonoylglycerol and anandamide oppositely modulate norepinephrine release from the rat heart sympathetic nerves.

Anandamide (10(-7) and 10(-6) M) as well as a synthetic cannabinoid HU210 (10(-8) to 10(-6) M) suppressed the norepinephrine release evoked by perivascular nerve stimulation (PNS) of the rat heart Langendorff's preparation. The effects of HU210 and the lower dose of anandamide were completely blocked by the cannabinoid CB1-receptor antagonist AM251, while that of anandamide at 10(-6) M was partly mediated by arachidonate-derived metabolites. 2-Arachidonoylglycerol (2-AG), at 10(-6) M in the presence of DFP and indomethacin, increased PNS-evoked norepinephrine release, which was completely blocked by AM251. The present results suggest that the two endocannabinoids may oppositely participate in the CB1-receptor-mediated modulation of sympathetic norepinephrine release.

Animals↗
PubMed2000

Genomic organisation and characterisation of the neural sex-determination gene fruitless (fru) in the Hawaiian species Drosophila heteroneura.

There are several mechanisms for the determination of sex. Sexual behaviour is part of the sex-determination cascade, and in Drosophila melanogaster male courtship is controlled in part by the fruitless gene. As part of a study of sexual behaviour in Hawaiian Drosophila, we have cloned the neural sex-determination gene fru from the Hawaiian picture-wing species Drosophila heteroneura. The fru gene has at least seven exons covering a region of 18kb and encodes three transcripts, fruA, fruB and fruC. Each transcript encodes a single ORF of 841, 678 and 691aa, respectively. The FRUA and FRUB proteins have a BTB protein-protein-binding domain and two zinc finger-like domains and are well conserved with the D. melanogaster proteins. The FRUC protein has a BTB domain but no zinc finger-like domains. The fru gene is expressed in 1-7 day old adult males as a 5.1kb transcript. This transcript is not seen in adult females, so the fru gene has a different pattern of sex-differential expression in the Hawaiian Drosophila compared with D. melanogaster.

Alternative Splicing↗
PubMed2000

Intraoperative electro-oculographic Monitoring for Skull Base Surgery.

During surgery on the skull base, preservation of the integrity of the ocular motor nerves is vitally important. Intraoperative electrophysiological monitoring methods for protecting such functions have been reported by several investigators. However, these methods so far have not been popularized sufficiently, due to the difficulty and complexity of the procedures involved. The authors have developed an extremely simple but far more reliable method using electro-oculography under total intravenous anesthesia with propofol to preserve the integrity of the ocular motor nerves. The ocular motor nerves were stimulated with a monopolar electrode intracranially, and the polarity of the waves was recorded using surface electrodes placed around the eyeball, yielding precise information concerning the locations of the oculomotor nerve and/or abducent nerve. In addition, by performing continuous monitoring, invasive procedures affecting the ocular motor nerves could be detected as spontaneous ocular movements. In practice at our department, this method has been applied in 12 cases with tumors close to the ocular motor nerves, and has produced excellent results.

Journal Article↗
PubMed2000

Genomic organisation of the neural sex determination gene fruitless (fru) in the Hawaiian species Drosophila silvestris and the conservation of the fru BTB protein-protein-binding domain throughout evolution.

We report the cloning and sequencing of the fru gene from the Hawaiian picture-wing species Drosophila silvestris. The fru gene has seven exons spanning 15-kb encoding two transcripts with ORFs of 841 and 695 amino acids. The protein encoded by the fruA transcript is well conserved with the D. melanogaster type A protein, particularly the BTB protein-protein-binding domain, which is encoded by exons I and II and is 100% conserved. The peptide encoded by exon III has several sequence differences but these are confined mostly to regions of repetitive sequence and exons IV to VI are well conserved. The peptide encoded by exon VII is semi-conserved for the 5' end and 100% conserved for the Zinc finger domains; the rest of the peptide is virtually unconserved. The FRUA protein has a BTB domain and two zinc finger domains whereas the FRUC protein only has the BTB domain. The genomic DNA sequence encoding the BTB domain of the fru gene has been cloned from 21 species of Diptera. The protein-coding sequence is highly conserved and the amino acid sequence is identical except for two changes in the Tephritidae. The intron sequences are completely unconserved except between very closely related species such as the Hawaiian Drosophila. The phylogeny produced using the BTB exon sequences suggests that the most closely related mainland Drosophila species to the Hawaiian clade is D. moriwakii of the melanica species group. The phylogeny also shows that the Scaptomyza are closely related to the Hawaiian Drosophila so supporting a Hawaiian origin for the Scaptomyza. The genus Zaprionus is placed in the subgenus Drosophila closely related to D. immigrans along with the genera Samoaia and Liodrosophila.

Amino Acid Sequence↗
PubMed2000

Thalamotomy caused by cardioversion in a patient treated with deep brain stimulation.

Deep brain stimulation (DBS) has been applied mainly for the treatment of intractable pain and involuntary movement disorders. Based on the rising numbers of patients undergoing DBS therapy, the possibility of emergent application of cardioversion for the treatment of occasional severe arrhythmia in DBS patients has also increased. However, there has been insufficient discussion about cardioversion in DBS patients. We employed a radiofrequency receiver that transmits to the brain impulses provided by an external generator through an antenna applied to the skin in front of the receiver. We experienced a patient who displayed almost complete cessation of his action tremor with thalamic stimulation. He also developed central dysesthetic pain and showed complete disappearance of his action tremor, even without stimulation, following successful application of cardioversion. It is considered that slight changes in the high-voltage electrical current or high-voltage electrical current spread induced central dysesthetic pain and almost identical effects to thalamotomy. We report for the first time a case of thalamotomy induced by cardioversion in a DBS patient. Clearly, we need to bear in mind that cardioversion has the capability to cause brain lesions in DBS patients with a radiofrequency receiver implanted subcutaneously at the anterior chest wall.

Atrial Fibrillation↗
PubMed2000

Effect of midodrine on chlorpromazine-induced orthostatic hypotension in rabbits: comparison with amezinium, etilefrine and droxidopa.

Orthostatic hypotension was produced in urethane-anesthetized rabbit by a combination of chlorpromazine (0.1 mg/kg, i.v.) and 45 degrees head-up tilt. The effect of midodrine (1 and 3 mg/kg, i.d.) was investigated in comparison with amezinium (10 and 30 mg/kg, i.d.), etilefrine (10 and 30 mg/kg, i.d.) and droxidopa (30 and 100 mg/kg, i.d.). The higher doses of each drug significantly mitigated the chlorpromazine-induced orthostatic hypotension, while none of the lower doses caused a significant effect. The effect of midodrine developed most rapidly; a significant effect was observed 25 min after administration. The order of onset time was midodrine < etilefrine < amezinium < droxidopa. The effect of droxidopa was significant only at 130 to 160 min after administration. The amplitude of effect was in the following order; midodrine = droxidopa > or = etilefrine > amezinium. Midodrine (3 mg/kg, i.d.) mitigated orthostatic hypotension induced by prazosin (0.1 mg/kg, i.v.), but not by pentolinium (0.6 mg/kg, i.v.). It is suggested that midodrine competes with chlorpromazine at alpha1-adrenoceptors and subsequently recovers reflex vasoconstriction. Midodrine may be useful to protect patients with impaired baroreflex activity from accidental orthostatic hypotension during treatment with neuroleptics.

Adrenergic alpha-Agonists↗
PubMed1999

Acidosis enhances translocation of protein kinase C but not Ca(2+)/calmodulin-dependent protein kinase II to cell membranes during complete cerebral ischemia.

Systemic hyperglycemia and hypercapnia severely aggravate ischemic brain damage when instituted prior to cerebral ischemia. An aberrant cell signaling following ischemia has been proposed to be involved in ischemic cell death, affecting protein kinase C (PKC) and the calcium calmodulin kinase II (CaMKII). Using a cardiac arrest model of global brain ischemia of 10 min duration, we investigated the effect of hyperglycemia (20 mM) and hypercapnia (pCO(2) 300 mmHg) on the subcellular redistribution of PKC (alpha, beta, gamma) and CaMKII to synaptic membranes and to the microsomes, as well as the effect on PKC activity. We confirmed the marked translocation of PKC and CaMKII to cell membranes induced by ischemia, concomitantly with a decrease in the PKC activity in both the membrane fraction and cytosol. Hyperglycemia and hypercapnia markedly enhanced the translocation of PKC-gamma to cell membranes while other PKC isoforms were less affected. There was no effect of acidosis on PKC activity, or on translocation of CaMKII to cell membranes. Our data strongly suggest that the enhanced translocation of PKC to cell membranes induced by hyperglycemia and hypercapnia may contribute to the detrimental effect of tissue acidosis on the outcome following ischemia.

Acidosis↗
PubMed1999

A rabbit model for evaluation of chlorpromazine-induced orthostatic hypotension.

The present study was conducted to develop an experimental model for evaluation of chlorpromazine-induced orthostatic hypotension in rabbits. In addition, the alpha-adrenoceptor blocking effect of chlorpromazine was investigated in isolated rabbit aorta and saphenous vein in comparison with prazosin. Chlorpromazine (0.1 and 1 mg/kg, i.v.) potentiated significantly a decrease in mean blood pressure at 1 min after the onset of head-up tilt in rabbits anesthetized with urethane alone, urethane+alpha-chloralose or nitrous oxide alone, but not in conscious and morphine+urethane+alpha-chloralose-anesthetized rabbits. There was a negative correlation (r=-0.986, p<0.01) between the extent of chlorpromazine-induced orthostatic hypotension and the amplitude of tilt-induced reflex tachycardia before chlorpromazine treatment. Both prazosin and pentolinium elicited orthostatic hypotension under all four anesthetic conditions. The pA2 value for chlorpromazine to antagonize norepinephrine-induced contraction in aorta was significantly larger than that in saphenous vein, whereas prazosin blocked aortic and venous contractions to a similar extent. These results suggest that a rabbit under an anesthesia which impairs tilt-induced reflex tachycardia may be useful for evaluation of orthostatic hypotension by chlorpromazine. The relatively low potential of chlorpromazine to produce orthostatic hypotension may be partly due to its weak venodilating action.

Adrenergic alpha-Antagonists↗
PubMed1999

Intraoperative electrooculographic monitoring of oculomotor nerve function during skull base surgery. Technical note.

Intraoperative monitoring techniques for protecting the integrity of the oculomotor nerves during skull base surgery have been reported by several investigators, all of which involved the use of electromyographic responses to extraocular muscles. However, these techniques have not yet become popular because of the complexity of the procedures. The authors report an extremely simple and far more reliable technique in which electrooculographic (EOG) monitoring is used. The oculomotor nerves were stimulated with a monopolar electrode during skull base exposure. The polarity of the EOG responses recorded with surface electrodes placed on the skin around the eyeball yielded precise information concerning the location and function of the oculomotor and abducent nerves. In addition, with the aid of continuous EOG monitoring that detected transient changes in the background waves, surgical procedures that might impinge on oculomotor nerve function could be avoided. The present technique has been used in eight patients with skull base tumors and with it, the authors have achieved excellent results.

Electrooculography↗
PubMed1999

A case of adenocarcinoma with clear cell carcinoma of the bladder.

A case of adenocarcinoma with clear cell carcinoma of the bladder in a 65-year-old male is reported. Our patient had a walnut-sized nodular tumor located on the anterior wall of the bladder. The patient underwent radical cystoprostatectomy with urethral hemi-Koch pouch. Histopathological examination revealed a lesion composed of poorly-differentiated adenocarcinoma and clear cell carcinoma with diffuse sheet patterns of cells with abundant, clear cytoplasm. The patient died of general metastasis 18 months after operation. To our knowledge this is the first case of adenocarcinoma with clear cell carcinoma arising from the anterior wall of the bladder in a male.

Adenocarcinoma↗
PubMed1998

Significance of measurement of prostate specific antigen (PSA) in familial prostate cancer lines.

The concentration of prostate specific antigen (PSA) in serum was measured in 20 brothers or sons in 10 families in which the father and son or brothers had prostate cancer using the E test TOSOH IIPA. The patients were between 32 and 70 years old with a mean age of 48.2 years. The PSA value was between 0.4 and 19.5 ng/ml with a mean value of 3.4 ng/ml. Five patients (25%) had PSA values exceeding the cut-off value of 4.0 ng/ml. After obtaining their consent, systematic prostate needle biopsy by transrectal ultrasonography was performed on 3 patients (15%). Prostate cancer was detected in all of them. Among them 2 patients were brothers, and since the other two brothers already had prostate cancer, all four brothers were confirmed to have prostate cancer. This is the first report of a familial prostate cancer in four brothers in Japan. In the western countries where the incidence of prostate cancer is higher than that in Japan, studies have been performed on the risk factors. Family history is one of the most important risk factors. In Japan, the incidence of prostate cancer is increasing rapidly. Moreover, patients with a prostate cancer family history are expected to increase. In such cases, prostate cancer screening should be performed aggressively from a young age.

Adult↗