Search PubMed⌕ Search

Biomedical subjects

S Miyazaki

Publications and source records attributed to S Miyazaki.

At least 397 records · Page 22Linked to original sources
PubMed1995

[Treatment results of acute nonlymphocytic leukemia in childhood--Kyushu Yamaguchi Children's Cancer Study Group].

Seventy-three children with acute nonlymphocytic leukemia (ANLL) have been treated with ANLL-85 and ANLL-88 protocol at Kyushu-Yamaguchi Children's Cancer Study Group between June, 1985 and February, 1993. Ten boys and 10 girls (0y4m-16ylm) were treated with the ANLL-85 protocol. The complete remission (CR) rate was 75% and the 5-year event free survival (EFS) was 20 +/- 9%. It was terminated because of frequent early relapse (within 6 months after CR). Thirty-four boys and 19 girls (0y3m-17ylm) were treated with the ANLL-88 protocol. The CR rate was 85% and the 5-year EFS was 32 +/- 7%. Early relapse rate with ANLL-88 was lower than that of ANLL-85, however 9 cases relapsed after terminating therapy. Although bone marrow transplantation (BMT) from related donors during the first CR was effective in ANLL-88, EFS was not improved. Recognition of risk factors and appropriate chemotherapy regimens with or without the support of stem cell transplantation may be necessary to cure children with ANLL.

Adolescent↗
PubMed1995

[Assessment of anxiolytics (2)--An elevated plus-maze test].

When rodents are placed on an elevated plus-maze which consisted of two enclosed arms and two open arms, they enter the enclosed arms more frequently and spend more time on the enclosed arms than on the open arms since they prefer the enclosed arms to the open arms. The elevated plus-maze test can measure effects of drugs based on this tendency of rodents. Anxiolytics increase the time spent on the open arms and number of entries into open arms, and anxiogenics decrease them. We investigated the basal behavior of mice and the effects of diazepam in the elevated plus-maze test using 4 mazes with different size. The basal behavior of mice were changed by the maze size, especially by the width of the open arms. Further, we suggested that the maze size might affect anxiolytic activity of drugs detected in this test. This test is very useful because it needs neither complicated training for rodents nor an expensive apparatus, and the anxiolytic effects of drugs can be easily measured. However, this test is difficult to detect putative anxiolytics acting on serotonin receptors. When this method is used for measuring the activity of drugs, the choice of experimental conditions and evaluation of the results should be carefully done.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1995

[A case of suprasellar arachnoid cyst followed up for a long time].

We followed a case of suprasellar arachnoid cyst for 12 years. The patient was a sixteen-year-old girl without particular problems in her general condition. She showed optic atrophy in both eyes and optic nerve hypoplasia with an inferotemporal quandranopsia in the left eye. A suprasellar arachnoid cyst communicating with the tubarachnoid space was found to extend into the sella turcica as an empty sella. A cyst wall was resected and a cyst-peritoneal shunt performed. After 12 years from the operation, sensitivity was slightly depressed in the visual field where it had already been disturbed. Although there are few reports in the literature on involvement of the optic nerves and chiasma by suprasellar arachnoid cysts, papilledema and optic atrophy are often found in children, and infero-temporal quandranopsia or homonymous hemianopsia have been reported. Visual field defects were most likely caused by compression of the optic nerve by cyst or prolonged papilledema. We also suspect that some kind of disturbance to the optic nerve occurred during extension of the arachnoid cyst as an empty sella, or during formation of arachnoid cyst in the fetus stage.

Adolescent↗
PubMed1995

Ameliorating effects of histidine on learning deficits in an elevated plus-maze test in mice and the contribution of cholinergic neuronal systems.

We investigated the effects of histidine on scopolamine-induced learning deficits in the elevated plus-maze test in mice. In this test, transfer latency, the time mice took to move from the open arm to the enclosed arm, was used as an index of learning and memory. Intraperitoneal administration of scopolamine (0.5 mg/kg) prolonged the transfer latency on day 2 as compared with that in the saline-treated group. Histidine loading (500, 800 and 1600 mg/kg) reversed the prolongation of the transfer latency induced by scopolamine. This ameliorating effect of histidine was abolished by alpha-fluoromethylhistidine, an inhibitor of histidine decarboxylase, suggesting that histidine itself has no such ameliorating effect. Moreover, the ameliorating effect of histidine was antagonized by a histamine H1-receptor antagonist, pyrilamine, but not by zolantidine, a histamine H2-receptor antagonist. Thus, histamine, a decarboxylated product of histidine, elicited an ameliorating effect on scopolamine-induced learning deficit via histamine H1 receptors in mice. In the biochemical study, histidine significantly decreased acetylcholine (ACh) levels in the cerebral cortex and diencephalon of mice, and also significantly decreased them in the midbrain at a dose of 500 mg/kg. Histidine significantly increased and decreased levels of metabolites of noradrenaline and serotonin, respectively, in the brains of mice. Levels of dopamine and its metabolites were not very affected by histidine in the brains of mice. These findings clearly indicate that there is a close relationship between histaminergic and cholinergic system in the brain, and that histamine may play certain important roles in learning and memory.

Acetylcholine↗
PubMed1995

A facile synthesis of 4'-thio-arabinonucleosides as potential antiviral agents from D-glucose.

As potential antiviral agents, 4'-thio-arabinonucleosides were synthesized. Methyl 3-O-benzyl-xylo-furanoside, readily obtained from D-glucose, was converted to 1,4-anhydro-4-deoxy-4-thio-arabinitol. The protection of hydroxyl groups and the Pummerer rearrangement, followed by Lewis acid induced glycosylation afforded 4'-thio-arabinonucleosides. The compounds showed anti HSV-1 activity.

Antiviral Agents↗
PubMed1995

Effects of thioperamide on the cholinergic system and the step-through passive avoidance test in mice.

We investigated the effects of thioperamide, a histamine H3-receptor antagonist, on a scopolamine-induced learning deficit in the step-through passive avoidance test in mice, and on contents of acetylcholine and choline in the brain. In a behavioral study, thioperamide (20 mg/kg) alone slightly ameliorated scopolamine-induced learning deficit, and pretreatment with zolantidine, a histamine H2-receptor antagonist, significantly enhanced the ameliorating effect of thioperamide. This enhanced ameliorating effect of thioperamide was antagonized by pyrilamine, a histamine H1-receptor antagonist and (R)-alpha-methylhistamine, a histamine H3-receptor agonist, suggesting that thioperamide showed the ameliorating effect via histamine H3 receptors and/or histamine H1 receptors. In the biochemical study, thioperamide (20 mg/kg) in combination with zolantidine (20 mg/kg) significantly increased contents of choline in most of brain regions. These findings suggest that there is a close relationship between histaminergic and cholinergic systems in the brain, and that the histaminergic system may play certain important roles in learning and memory.

Acetylcholine↗
PubMed1994

Effects of 1-amino-5-bromouracil on the benzodiazepine-GABAA receptor complex.

We investigated the effects of 1-amino-5-bromouracil on the benzodiazepine-gamma-aminobutyric acid (GABA)A receptor complex to elucidate its central action. 1-Amino-5-bromouracil neither displaced nor enhanced [3H]muscimol, [35S]t-butylbicyclophosphorothionate (TBPS), or [3H]dehydroepiandrosterone sulfate binding to the rat brain synaptosomal membranes. The anesthesia induced by 1-amino-5-bromouracil was potentiated by diazepam, pentobarbital, and muscimol, and was antagonized by picrotoxin but not by bicuculline. 1-Amino-5-bromouracil protected mice from picrotoxin-induced seizure and slightly ameliorated TBPS-induced seizure, but did not antagonize bicuculline-induced seizure. Diazepam antagonized both the bicuculline- and the picrotoxin-induced seizure, and pentobarbital antagonized the picrotoxin- and the TBPS-induced seizure. Our in vivo studies suggest that part of the central action of 1-amino-5-bromouracil is concerned with the benzodiazepine-GABAA receptor complex including the chloride channel.

Anesthesia↗
PubMed1994

N-methyl-D-aspartate receptor-mediated, prolonged afterdischarges of CA1 pyramidal cells following transient cerebral ischemia in the rat hippocampus in vivo.

We previously reported the post-ischemic potentiation (PIP) of synaptic efficacy in hippocampal Schaffer collateral/CA1 responses of the rat beginning at 6-8 h following 12 min transient cerebral ischemia in vivo. The present study demonstrated that repetitive stimulation with a relatively low frequency (5 Hz, 6 s), which produced short-lasting afterdischarges (ADs; duration, 4.49 +/- 4.26 s; n = 7) in sham-controls, resulted in prolonged ADs (duration, 26.33 +/- 12.63 s; n = 6; P < 0.001) at the same period after ischemia. The PIP was not affected by 2-amino-5-phosphonovalerate (APV) administered via microdialysis at 7 h post-ischemia. The prolonged ADs in response to repetitive stimulation were, however, reversed to short-lasting ADs (duration, 7.13 +/- 1.44 s; n = 4; P < 0.02) by the same procedure, leaving the response to single stimulation unaffected. These findings suggest that, during the reperfusion period, Ca2+ influx into the CA1 pyramidal cells can be greatly increased through N-methyl-D-aspartate (NMDA) receptor-coupled ion channels if appropriately timed multiple synaptic inputs bombard these cells. Such Ca2+ influx may contribute to delayed death of CA1 pyramidal cells after transient cerebral ischemia if synaptic activity is maintained at relatively high levels during the reperfusion period.

Animals↗
PubMed1994

Effects of 1 alpha-hydroxyvitamin D3 on lumbar bone mineral density and vertebral fractures in patients with postmenopausal osteoporosis.

The effects of 1 alpha-hydroxyvitamin D3 [1 alpha(OH)D3] on bone mineral density, fracture incidence, and bone metabolism were evaluated by a double-blind, placebo-controlled study. Eighty postmenopausal osteoporotic Japanese women (71.9 +/- 7.3 years, mean +/- SD) were randomly assigned to 1 microgram of 1 alpha(OH)D3 daily or inactive placebo for 1 year. All patients were given supplemental calcium (300 mg of elemental calcium daily). Lumbar (L2-L4) bone mineral density (BMD) determined by dual energy X-ray absorptiometry increased 0.65% with 1 alpha(OH)D3 treatment and decreased 1.14% with placebo (P = 0.037). BMD in both the femoral neck and Ward's triangle did not yield any significant differences between the two groups, whereas trochanter BMD in the 1 alpha(OH)D3-treated group increased 4.20% and decreased 2.37% with placebo (P = 0.055). X-ray analysis demonstrated that new vertebral fractures occurred in two patients with 1 alpha(OH)D3 and in seven patients with placebo. The vertebral fracture rate in the treated group was significantly less (75/1000 patient years) than in the control group (277/1000 patient years; P = 0.029). Hypercalcemia (12.1 mg/100 ml) occurred in one patient receiving 1 alpha(OH)D3; however, the serum calcium level in this patient promptly decreased to the reference range after cessation of the treatment. There were no significant changes in serum creatinine level in either group. A significant increase in urinary excretion of calcium was found but there was no significant change in urinary excretion of hydroxyproline in the treated group. The serum level of bone-derived alkaline phosphatase activity significantly decreased by -26 +/- 26 (mU/ml) after the treatment (P = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1994

How to deal with advanced cases of neuroblastoma detected by mass screening: a report from the Pediatric Oncology Study Group of the Kyushu area of Japan.

Since 1985, a nationwide program of mass screening (MS) for neuroblastoma has been underway for 6-month-old infants throughout Japan. As a result, the number of patients with stage I or II disease has obviously increased, and this has resulted in overall improvement of the prognosis for neuroblastoma. Some cases detected by MS were already in an advanced stage and have also had a good prognosis. In such cases, no definitive treatment protocol has been developed. Therefore, the authors investigated (1) the clinical and biological features of the advanced neuroblastoma cases detected by MS and (2) the best way to deal with such cases. The authors analyzed 94 cases of advanced-stage neuroblastoma registered in the Kyushu area (population, 15 million) between 1985 and 1990. Eighteen cases (16 stage III, 2 stage IV) were found by MS, and the others (23 stage III, 53 stage IV) were diagnosed clinically. The following results were obtained: (1) No N-myc amplifications were observed in cases detected by MS, whereas 16 of the 45 examined patients in the non-MS group had high amplifications of N-myc. (2) With regard to Shimada's classification, DNA content, and S-100 protein positivity, most of the advanced tumors found by MS showed characteristics indicating a good prognosis. (3) The 5-year survival rate for the non-MS group is less than 25%, whereas all of the patients whose tumors were detected by MS are alive, even after undergoing mild chemotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗
PubMed1994

Effect of 1-amino-5-bromouracil on brain monoamine metabolism in rats.

The effect of 1-amino-5-bromouracil (ABU), a novel central-acting agent, on monoaminergic neurotransmitter levels of rat brain was investigated. Under the nonstressed condition, ABU (20 and 30 mg/kg intraperitoneally [IP]) did not affect monoamine metabolism, whereas diazepam (5 mg/kg IP) increased the 3-methoxy-4-hydroxyphenylethylene glycol (MHPG)/noradrenaline (NA) ratio. One-hour immobilization stress increased the MHPG/NA ratio in various brain regions of drug-naive rats, but did not increase the homovanilic acid (HVA) plus 3,4-dihydroxyphenylacetic acid (DOPAC)/dopamine (DA) ratio or the 5-hydroxyindole acetic acid (5-HIAA)/serotonin (5-HT) ratio. Pretreatment with ABU or diazepam suppressed the activation of noradrenergic neurons induced by immobilization stress. By contrast, electric foot shock stress increased the MHPG/NA and HVA+DOPAC/DA ratios. Pretreatment with ABU or diazepam suppressed the activation of noradrenergic and dopaminergic cortical neurons by electric foot shock stress. These results indicate that these two physiologic stresses affected monoaminergic neurons differently and that their effects were suppressed by ABU and diazepam.

Animals↗
PubMed1994

Sperm-egg fusion in the sea urchin is blocked in Mg(2+)-free seawater.

Magnesium ions as well as calcium ions are required for successful fertilisation in sea urchins. In the absence of Mg2+ spermatozoa attached to the egg plasma membrane, their acrosomal processes passing through the vitelline envelope, but could not enter the egg cytoplasm (Sano et al., Dev. Growth Differ. 22, 531-41, 1980). Such an individual spermatozoon was observed microscopically to resume entry into the egg immediately after the addition of a sufficient amount of Mg2+ to the surrounding medium. Neither any change in membrane potential nor an increase in intracellular Ca2+ concentration of the egg was observed after insemination in the absence of Mg2+, although both could be observed after the addition of Mg2+. The sperm heads did not show fluorescence when attached to the surface of an egg previously microinjected with mithramycin A in Mg-free seawater, indicating that there was no connection between the sperm and the egg. Therefore, occurrence of fertilisation potential must be a post-fusional event. These results suggest that Mg2+ are indispensable for fusion between the sperm acrosomal membrane and the egg plasma membrane.

Animals↗
PubMed1994

Endoscopic ligation of gastric varices using a detachable snare.

A new technique of endoscopic treatment for gastric varices is presented here, which was applied in 10 patients, either electively (n = 9) or as emergency therapy for bleeding (n = 9) or as emergency therapy for bleeding (n = 1). A detachable snare is placed endoscopically, tightened around the varix, and then detached using a similar principle to that of band ligation. Following one or two treatment sessions (one snare applied in seven cases, two snares applied in three cases), eradication of gastric varices was observed in all patients. No significant complications were encountered, and nine of 13 snares passed spontaneously, the remaining ones being removed when found during follow-up endoscopy. Short-term follow-up (4-12 months, mean: 7.2 months) did not show either reappearance of varices or rebleeding in any of the patients. Angiography and endoscopic ultrasonography performed in four patients before and after treatment showed regression or disappearance of intramural vessels. Further studies will show the relative value of this new technique compared to other treatment modalities such as banding or cyanoacrylate injection.

Aged↗
PubMed1994

Hyposecretion of atrial natriuretic peptide due to associated right atrial infarction in a patient with acute right ventricular infarction?

A patient with acute right ventricular infarction who showed hyposecretion of atrial natriuretic peptide (ANP) in spite of abnormally high right atrial pressure and who died of a severe low cardiac output syndrome is reported. Right atrial infarction, which was proven at autopsy, may be responsible for this endocrine failure.

Atrial Function, Right↗