Biomedical subjects

H Nakane

Publications and source records attributed to H Nakane.

At least 55 records · Page 3Linked to original sources

PubMed1995

Juberg-Marsidi syndrome: report of an additional case.

We report on a 2-year-old boy with Juberg-Marsidi syndrome. He has mental retardation, short stature, micropenis, cryptorchidism, and minor facial abnormalities. His Leydig cells responded to the administration of human chorionic gonadotropin and there were positive responses of LH and FSH to the administration of LH-RH. He showed normal weight gain and head circumference which have not been described previously. The association of Juberg-Marsidi syndrome with HbH disease was ruled out in the propositus.

Abnormalities, Multiple↗

PubMed1995

High incidence of ultraviolet-B-or chemical-carcinogen-induced skin tumours in mice lacking the xeroderma pigmentosum group A gene.

Xeroderma pigmentosum (XP) is an autosomal recessive disorder characterized by a high frequency of skin cancer on sun-exposed areas, and neurological complications. XP has a defect in the early step(s) of nucleotide-excision repair (NER) and consists of eight different genetic complementation groups (groups A-G and a variant). We established XPA (group-A XP) gene-deficient mice by gene targeting of mouse embryonic stem (ES) cells. The XPA-deficient mice showed neither obvious physical abnormalities nor pathological alterations, but were defective in NER and highly susceptible to ultraviolet-B- or 9,10-dimethyl-1,2-benz[a]anthracene-induced skin carcinogenesis. These findings provide in vivo evidence that the XPA protein protects mice from carcinogenesis initiated by ultraviolet or chemical carcinogen. The XPA-deficient mice may provide a good in vivo model to study the high incidence of skin carcinogenesis in group A XP patients.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1995

Isradipine, a calcium channel blocker, attenuates the ischemia-induced release of dopamine but not glutamate in rats.

This study was designed to investigate the role of the L-type voltage sensitive calcium channel blocker, isradipine, in the ischemia-induced release of neurotransmitters. Male spontaneously hypertensive rats were subjected to cerebral ischemia for 60 min by bilateral carotid artery occlusion, and recirculated for 120 min. Isradipine (0.25 mg/kg n = 6) or vehicle (n = 6) was administered subcutaneously at 20 min before ischemia. In the striatum, cerebral blood flow was determined by the hydrogen clearance method and concentrations of extracellular dopamine and glutamate were measured by in vivo brain dialysis technique. Extracellular dopamine in the vehicle-treated group increased by 180-fold from the basal level, and glutamate by 24-fold during cerebral ischemia. Isradipine significantly attenuated the ischemic release of dopamine to 33-34% (P < 0.05) of the vehicle group, while it did not affect glutamate release. It is suggested that the release mechanism of dopamine and glutamate during cerebral ischemia may be different, especially in the dependence on the L-type calcium channels.

Animals↗

PubMed1995

Involvement of dopamine D1 receptors in phencyclidine-induced behavioral stimulation in rats.

The effects of dopamine receptor antagonists on phencyclidine (PCP)-induced behaviors were examined in rats. Acute administration with PCP (7.5 mg/kg i.p.) produced various behavioral changes, such as increases of spontaneous activity, head-weaving, sniffing, rearing, back-pedaling, and ataxia. To determine which dopamine receptor subtypes were involved in mediating the PCP-induced behaviors, SCH 23390 (0.05 and 0.5 mg/kg), sulpiride (20 and 100 mg/kg), or haloperidol (0.05 and 0.5 mg/kg) were pretreated 30 min before PCP treatment (7.5 mg/kg). A higher dose of SCH 23390 significantly reduced the increase of spontaneous activity induced by PCP. Both doses of sulpiride did not affect the PCP-induced behaviors. A higher dose of haloperidol decreased the PCP-induced spontaneous activity, whereas a lower dose of haloperidol enhanced the activity. Ketanserin (0.5 and 5 mg/kg) did not alter any PCP-induced behaviors. These results suggest that the D1, but not D2, dopamine receptor subtype may be involved in the PCP-induced behavioral abnormality.

Animals↗

PubMed1995

Cerebral blood flow and metabolism in hypertensive patients with cerebral infarction.

The authors investigated, by positron emission tomography, the effect of long-standing hypertension on cerebral blood flow (CBF) and oxygen metabolism in patients with chronic atherothrombotic brain infarction. In the nonbrain infarct (non-BI) group (n = 13, mean age: sixty-two years), the regional CBF (rCBF) was decreased significantly with a rise in the mean arterial blood pressure (MABP) in the cerebral cortexes (r = -0.575) and the deep gray matter (r = -0.451), whereas the regional cerebral metabolic rate for oxygen (rCMRO2) remained unchanged. In the brain infarct (BI) group (n = 22, mean age: fifty-eight years), however, the rCBF as well as the rCMRO2 were reduced even in the normotensive patients and thus did not correlate with the MABP. These results suggest that long-standing hypertension per se causes a reduction in the rCBF but not in the oxygen metabolism with a compensatory increase in the oxygen extraction fraction. On the other hand, patients with brain infarction, even normotensives, show a diffuse decrease in cerebral circulation and metabolism, which is probably due to the more severe sclerotic changes that take place in the cerebral vessels.

Blood Pressure↗

PubMed1994

CRF receptor antagonist attenuates stress-induced noradrenaline release in the medial prefrontal cortex of rats.

Noradrenaline release in rat medial prefrontal cortex (PFC) was measured using a brain microdialysis technique. Immobilization stress increased noradrenaline release to a maximum level of 248.7 +/- 12.8% of the basal release, which was significantly attenuated by preinjection of alpha-helical CRF9-41 (50 micrograms/rat) into the lateral cerebroventricle. Intracerebroventricular injection of CRF also increased noradrenaline release in the medial PFC. These results suggest that immobilization-stress facilitates noradrenaline release in the medial PFC through activation of the CRF system in the brain.

Animals↗

PubMed1994

An interleukin-1 beta-induced noradrenaline release in the spleen is mediated by brain corticotropin-releasing factor: an in vivo microdialysis study in conscious rats.

The purpose of this study was to investigate whether an intraperitoneal injection of interleukin-1 beta (IL-1 beta) affects noradrenaline release in the spleen through its action on the brain of conscious rats. An in vivo microdialysis technique consisting of high-performance liquid chromatography with electrochemical detection was used for chronic monitoring of the splenic noradrenaline. The perfusion of a high concentration of K+ Ringer solution through the microdialysis probe significantly increased the concentration of noradrenaline in the spleen, while a perfusion of either Ca(2+)-free or tetrodotoxin-containing Ringer solution decreased the noradrenaline level in the dialysate. These results indicate that the noradrenaline recovered in the splenic dialysate is mainly derived from the nerve terminals of the splenic sympathetic nerve. The intraperitoneal injection of IL-1 beta (100 ng/kg) produced an immediate and significant increase in the noradrenaline levels in the spleen. The increased level reached a maximum level 40 min after injection and then gradually returned to the basal level. An intracerebroventricular (ICV) injection of a corticotropin-releasing factor (CRF) antagonist (alpha-helical CRF9-41, 30 micrograms) significantly attenuated the IL-1 beta-induced increase in the noradrenaline release. An ICV injection of CRF (2 micrograms) also caused a significant increase in splenic noradrenaline, which showed two distinct peaks at 20 and 140 min, respectively. These results suggest that the intraperitoneal injection of IL-1 beta facilitates noradrenaline release in the spleen through activation of the sympathetic nerve, and the increased sympathetic activity is, at least in part, due to the excitation of neurons containing CRF in the brain.

Animals↗

PubMed1994

Stress-induced norepinephrine release in the rat prefrontal cortex measured by microdialysis.

Norepinephrine (NE) release in the medial prefrontal cortex (PFC) of rats was studied during immobilization using an intracerebral microdialysis technique. A series of experiments using pharmacological and physiological manipulations indicated that the NE recovered in the medial PFC dialysate was mainly derived from nerve terminals and that the dorsal noradrenergic bundle was a major source of NE in the medial PFC. Immobilization stress immediately elevated NE levels to 176.0 +/- 9.0% of basal release, and this increase continued for the entire period of stress and 20 min after termination of the stress. Preinjection of a benzodiazepine receptor agonist, diazepam (5 mg/kg ip), significantly attenuated immobilization-induced NE release, while injection of an anxiogenic compound, FG-7142 (20 mg/kg ip), facilitated NE release in an obviously nonstressed condition. These results therefore suggest that stressful stimuli activate the NE system in the medial PFC, which may be modulated by an activation of benzodiazepine receptors in the brain.

Animals↗

PubMed1994

Myelodysplastic syndrome associated with immunoblastic lymphadenopathy-like T-cell lymphoma: simultaneous clinical improvement with chemotherapy.

A 75-year-old woman presented with anemia, lymphadenopathy, hepatomegaly and lingual tumor, but no constitutional symptoms. The laboratory data showed pancytopenia and polyclonal hypergammaglobulinemia. A bone marrow aspirate represented an apparent myelodysplastic syndrome (MDS) feature, specifically, refractory anemia with excess of blasts. A lymph-node biopsy revealed the disappearance of normal architecture, small arborizing blood vessels, large lymphoid cells with prominent cytoplasm (so-called pale cells) and a clonal proliferation of T-lymphocytes. The patient was diagnosed as having MDS associated with immunoblastic lymphadenopathy (IBL)-like T-cell lymphoma. She was subsequently treated with cyclophosphamide, adriamycin, vincristine and prednisolone for lymphoma which successfully induced a remission of not only the T-cell lymphoma but also the MDS. The case suggested that MDS might be a paraneoplastic complication of IBL-like T-cell lymphoma.

Aged↗

PubMed1993

Crystallization and preliminary X-ray diffraction studies of Bacillus stearothermophilus farnesyl diphosphate synthase expressed in Escherichia coli.

Thermostable farnesyl diphosphate synthase (EC 2.5.1.10) from Bacillus stearothermophilus, which was overexpressed in Escherichia coli, has been crystallized by the vapor-diffusion procedure. Tetragonal crystals were obtained using ammonium sulfate as a precipitant. The crystals diffracted X-rays to about 3 A resolution. The diffraction pattern indicated that the space group is I4(1)22 with unit-cell dimensions of a = b = 114 A and c = 247 A. It is thought that the asymmetric unit comprises two or three molecules of farnesyl diphosphate synthase.

Alkyl and Aryl Transferases↗

PubMed1993

Alkaline phosphodiesterase I release from eucaryotic plasma membranes by phosphatidylinositol-specific phospholipase C. III. The release from tumor cells.

1. Alkaline phosphodiesterase I release from two tumor cell lines, KB III or AH-130 cells, by the action of phosphatidylinositol-specific phospholipase C (PIPLC) of Bacillus thuringiensis was studied. 2. A significant amount of alkaline phosphodiesterase I was released from both the cell suspension and homogenate of KB III cells, but not from AH-130 cells. 3. The release of the enzyme from KB III cells was dependent on, or proportional to, the reaction time and the PIPLC or cell concentrations. 4. Alkaline phosphatase and 5'-nucleotidase were also released from KB III cells, while gamma-glutamyl transpeptidase and dipeptidyl peptidase IV were not solubilized. The enzyme release by the action of PIPLC was suppressed when purified anti-PIPLC antibody was added to the reaction mixture. This suggests that the enzyme release must be due to the direct action of PIPLC on KB III cells. 5. The alkaline phosphodiesterase I released from KB III cells had a mol. wt of 240,000 and was activated by Mg2+, but strongly inhibited by EDTA and thiol reagents and by 5'-nucleotide-containing compounds. Although KB III cells were derived from Homo sapiens tumor, the released alkaline phosphodiesterase I appeared to be very similar to enzymes obtained from normal tissues of Rattus norvegicus.

5'-Nucleotidase↗

PubMed1993

Duodenal hemorrhage and dermal vasculitis associated with mixed connective tissue disease.

We describe a 23-year-old woman with mixed connective tissue disease (MCTD) who developed duodenal bleeding responsive to treatment with corticosteroid and recurrent skin eruptions due to leukocytoclastic vasculitis. The endoscopic findings revealed patchy, reddened, edematous, friable mucosa with scattered small ulcers and oozing of blood in the second portion of the duodenum. Endoscopic pictures from the onset to healing are presented. This appears to be the first recorded occurrence of such findings in MCTD.

Adult↗

PubMed1992

Attenuation of ischemic and postischemic damage to brain metabolism and circulation by a novel Ca2+ channel antagonist, NC-1100, in spontaneously hypertensive rats.

We investigated the effect of a newly synthesized Ca2+ channel antagonist, NC-1100, on cerebral blood flow (CBF) and metabolism in spontaneously hypertensive rats. The rats received a bolus injection of 0.2 or 1.0 mg/kg NC-1100 i.v. and 1-h cerebral ischemia was then induced by bilateral carotid artery occlusion (group 1). The rats in group 2 were continuously infused with NC-1100 0.03 or 0.1 mg/kg per min, starting immediately after bilateral carotid artery occlusion, for the 1 h of ischemia and following 3-h recirculation. Group 1: during ischemia, CBF in all rats decreased to 6-8% of the resting values. At 1 h cerebral ischemia, brain tissue lactate increased 11.5-, 10.1- and 9.8-fold of the normal control given vehicle or NC-1100, 0.2 and 1.0 mg/kg, respectively. The ATP levels were better preserved by NC-1100 administration; 0.61 +/- 0.04 (mean +/- S.E.M.), 0.80 +/- 0.09 and 0.97 +/- 0.14 mmol/kg (P < 0.05 vs. vehicle), respectively. Group 2: during recirculation, CBF in NC-1100-treated rats returned to 83-90% of the resting values, but to only 65% in the vehicle group. Postischemic brain lactate at 3 h was less well preserved and ATP was dose dependently better preserved in NC-1100- than vehicle-treated rats. It is considered that pre- as well as postischemic administration of a Ca2+ channel antagonist, NC-1100, is beneficial to attenuate and also ameliorate the metabolic and circulatory derangement in the ischemic brain.

Adenosine Triphosphate↗

PubMed1992

Site-specific DNA cleavage by mammalian DNA topoisomerase II induced by novel flavone and catechin derivatives.

Four naturally occurring flavones (baicalein, quercetin, quercetagetin and myricetin) and two novel catechins [(-)-epicatechin gallate and (-)-epigallocatechin gallate, from the tea plant Camellia sinensis], which are known inhibitors of reverse transcriptase, were shown to induce mammalian topoisomerase II-dependent DNA-cleavage in vitro. The flavones differed from the catechins in causing unwinding of duplex DNA, but both classes of compound induced enzymic DNA breakage at the same sites on DNA. Moreover, the cleavage specificity was the same as that for the known intercalator 4'-(acridin-9-ylamino)methanesulphon-m-anisidide, suggesting that these agents trap the same cleavable complex. Analysis of some 30 flavonoid compounds allowed elucidation of the structure-function relationships for topoisomerase II-mediated DNA cleavage. For flavonoid inhibitors an unsaturated double bond between positions 2 and 3 of the pyrone ring and hydroxy groups at the 5, 7, 3' and 4' positions favoured efficient cleavage. Hydroxy substitutions could be tolerated at the 3, 6 and 5' positions. Indeed, the absence of substituents at the 3', 4' and 5' positions could be compensated by a hydroxy group at position 6 (baicalein). Similar requirements have been reported for flavonoid inhibitors of protein kinase C that act competitively with ATP, suggesting interaction with a conserved protein feature. Formation of the cleavable complex is a cytotoxic lesion that may contribute to the growth-inhibitory properties of flavones observed for three human tumour cell lines. These results are discussed in regard to the selectivity of antiviral agents.

Animals↗

PubMed1992

Early computed tomographic findings for thrombolytic therapy in patients with acute brain embolism.

BACKGROUND AND PURPOSE: The benefits and safety of thrombolytic therapy was studied in patients with acute brain embolism. METHODS: We intravenously administered recombinant tissue plasminogen activator (20-30 MU for 1 hour) to 10 patients with acute (less than 6 hours) brain embolism and examined the neurological outcomes in relation to the findings on computed tomography and angiography. RESULTS: The symptoms ameliorated in four patients within 24 hours after onset, and reopening of the occluded arteries occurred in two of the patients immediately after recombinant tissue plasminogen activator infusion. On the initial computed tomographic scan (less than 3 hours), four patients had already demonstrated early indications of brain ischemia, that is, an obscure margin of the lentiform nuclei, reduced tissue attenuation, or effacement of cortical sulci. These patients failed to demonstrate reopening of the occluded arteries, and one developed a massive brain hemorrhage with clinical deterioration. Of the remaining six patients, two obtained clinical improvement with recanalization soon after the therapy and demonstrated little to slight hemorrhagic complications. The outcomes at 1 month were favorable in five patients and poor in three; death occurred in two. CONCLUSIONS: Thrombolytic therapy with recombinant tissue plasminogen activator may be safe and effective when there are no early computed tomographic findings within 3 hours from the onset of embolic stroke.

Adult↗

PubMed1992

Synthesis and anti-human immunodeficiency virus type 1 (HIV-1) activity of 3-substituted derivatives of 3'-azido-3'-deoxythymidine (AZT), and inhibition of HIV-1 reverse transcriptase by their 5'-triphosphates.

Various 3-substituted 3'-azido-3'-deoxythymidine analogs (2a-i) were prepared by the reaction of 3'-azido-3'-deoxythymidine (1), AZT with N,N-dimethylformamide dialkylacetal or alkyl bromide in the presence of base and their activities against human-immunodeficiency virus type-1 (HIV-1) were evaluated. The corresponding 5'-triphosphate analogs (9) were also synthesized in order to examine inhibition of HIV-1 reverse transcriptase activity. Beyond expectation, some N3-derivatives of AZT were found to reserve the anti-HIV-1 activity to some extent. Among the compounds (2a-i) obtained, 3-allyl-AZT (2e) was the most active against HIV-1 replication in MT-4 cells in vitro with an EC50 value of 0.9 microM. 3-Allyl-AZT 5'-triphosphate (9e), however, exhibited no inhibition of HIV-1 reverse transcriptase activity.

Antiviral Agents↗

PubMed1991

Inhibition of HIV-reverse transcriptase activity by some phloroglucinol derivatives.

Four phloroglucinol derivatives, named mallotophenone (5-methylene-bis-2,6-dihydroxy-3-methyl-4-methoxyacetophenone), mallotochromene (8-acetyl-5,7-dihydroxy-6-(3-acetyl-2,4- dihydroxy-5-methyl-6-methoxybenzyl)-2,2-dimethylchromene), mallotojaponin (3-(3,3(dimethylallyl)5-(3(acetyl-2,4- dihydroxy-5-methyl-6-methoxybenzyl)-phloracetophenone) and mallotolerin (3-(3-methyl-2-hydroxybut-3-enyl)-5(3-acetyl-2,4- dihydroxy-5-methyl-6-methoxybenzyl)-phloracetophenone), have been tested for their ability to inhibit the activity of human immunodeficiency virus (HIV)-reverse transcriptase. Under the reaction conditions with (rA)n.(dT)12-18 as the template.primer, the enzyme activity was inhibited by approximately 70% in the presence of 10 micrograms/ml mallotochromene or mallotojaponin, whereas mallotophenone and mallotolerin were much less inhibitory to the enzyme. The enzyme activity was also inhibited, though to lesser extent, by these compounds under similar conditions with initiated MS-2 phage RNA as the template.primer. The mode of inhibition was, as analyzed with mallotojaponin, competivite with respect to the template.primer, (rA)n.(dT)12-18, and non-competitive with respect to the triphosphate substrate, dTTP. The Ki value of mallotojaponin for HIV-reverse transcriptase was determined to be 6.1 microM.

Base Sequence↗

PubMed1991

Inhibition of HIV-reverse transcriptase activity by asterriquinone and its analogues.

Asterriquinone (ARQ; 2,5-bis-[1'-(1", 1"-dimethyl-2"-propenyl)- indol-3'-yl]-3,6-dihydroxy-1,4-benzoquinone) and its three analogues [i.e., 3,6-dihydroxy-2-[2'-(1", 1"-dimethyl-2"-propenyl)-indol-3'-yl]-5-[1', 7'- (1",1"-dimethylpropano)-indol-3'-yl]-1,4-benzoquinone (B1-4), 3,6-dihydroxy-2-[2'-(1", 1"-dimethyl-2"-propenyl)-indol-3'-yl]-5-indol-3'-yl-1,4-benzoquinone (C1-1) and 3,6-dihydroxy-2,5-diindol-3'-yl-1,4-benzoquinone (D-1)] were found to be strong inhibitors of the activity of reverse transcriptase from human immunodeficiency virus type-1. Under the reaction conditions employed, the enzyme activity was inhibited by more than 70% in the presence of 10 microM each of these compounds. The mode of inhibition by these compounds was competitive with respect to the template.primer, (rA)n.(dT)12-18, and noncompetitive with respect to the triphosphate substrate, dTTP. The Ki values of HIV-1 reverse transcriptase were determined to be 2.3, 1.5, 0.1 and 0.3 microM for ARQ, B1-4, C1-1 and D-1, respectively.

Aspergillus↗