Intellectual work using a video game inhibits post hyperventilation hyperpnoea following voluntary hyperventilation while it stimulates breathing at rest.
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Adult↗
Biomedical subjects
H Hirata
Publications and source records attributed to H Hirata.
Relationship of alcohol-induced changes in Mg(2+)-ATPase activity of rabbit intestinal brush border membrane with changes in fluidity of its lipid bilayer.
We examined the effects of seven n-alkyl alcohols (from n-butyl to n-undecyl alcohol), isoamyl alcohol and benzyl alcohol on the activity of membrane enzyme Mg(2+)-ATPase of the rabbit small intestinal brush border membrane. Their relationships with the changes in the fluidity of the membrane lipid bilayer were examined through studies on the fluorescence anisotropies of diphenylhexatriene (DPH) and its ionic derivatives. Good linear correlations were found both between the partition coefficients of the alcohols and their concentrations causing similar decreases in the activity of Mg(2+)-ATPase and between their partition coefficients and the alcohol-induced changes in fluorescence anisotropies. Within the concentration range of the alcohols tested, including isoamyl alcohol and benzyl alcohol, the decreases in activity of the membrane enzyme Mg(2+)-ATPase clearly corresponded with the decreases in fluorescence anisotropy of DPH, which is thought to be located within the hydrophobic core of the membrane. From these findings, one possible explanation is that inhibition of this enzyme by the alcohols is due to perturbation of the lipid bilayer of the brush border membrane.
Adenosine Triphosphatases↗
M1 receptors in blood pressure-controlled ischemic spontaneously hypertensive rats.
BACKGROUND AND PURPOSE: Hypertension is a primary aggravating factor in cerebral infarction. An acute rise in blood pressure (BP) at the time of a stroke may be harmful to the brain in a hypertensive subject because both cerebral vascular structure and function are altered by hypertension. Muscarinic M1 receptors are concerned with memory and learning. We aimed to evaluate the effect of controlling BP in hypertensive subjects at the time of stroke with a biochemical index of brain damage. METHODS: We gave a single dose of either the antihypertensive alpha-blocker phentolamine (2 mg/kg IP) or the calcium antagonist nicardipine (2 mg/kg IP) at the start of bilateral carotid artery occlusion to spontaneously hypertensive rats undergoing 3 hours of transient ischemia; we measured the time course of mean BP (MBP) and changes in the M1 receptor and its mRNA in three brain regions 2 weeks after the transient ischemia. RESULTS: Administration of phentolamine or nicardipine not only significantly suppressed the ischemia-induced rise of MBP, it actually decreased MBP during ischemia. In an ischemic control group, M1 receptor binding decreased in the frontal cortex and M1 receptor mRNA increased in the hippocampus 2 weeks after the ischemia. In contrast, both phentolamine- and nicardipine-treated ischemic rats showed no changes in either index compared with sham-operated controls. CONCLUSIONS: Controlling BP during an ischemic insult attenuates ischemia-induced damage of M1 receptors in the brain of spontaneously hypertensive rats. These results suggest that a rapid intensive increase of BP at the time of a stroke may exacerbate brain damage in hypertensive individuals.
Animals↗
[Complete remission in acute myeloblastic leukemia (M0) after treatment with rhG-CSF].
A 57-year-old man was admitted because of fever and night sweat. The bone marrow was hypercellular with 86.4% blast cells. The diagnosis of AML (M0) was made, because the blast cells were negative for peroxidase stain and had CD13 and no lymphoid antigens in marker analysis. The patient was treated with BH-AC.TMP, BH-AC.MVP and low dose Ara-C without any hematological improvement, and even additional treatment with medium dose Ara-C resulted in 66.4% blast cells in the bone marrow. Subsequent administration of rhG-CSF (150 micrograms/day) by continuous intravenous infusion resulted in the decrease of the blast cells in the bone marrow to a level that was evaluated as complete remission. He remains in complete hematological remission at present. As shown in this case, rhG-CSF might be an effective agent for the treatment of AML, even if the mechanism of its effectiveness is unclear at present. Further clinical studies should will supply useful information to analyze the pathophysiology of AML.
Granulocyte Colony-Stimulating Factor↗
[Contrast-enhanced 3D MR angiography of the chest and abdomen with breath-holding using phase reordering].
This report presents the feasibility of phase-recordered contrast-enhanced three-dimensional MR angiography in 32 consecutive patients with vascular abnormalities in the chest and abdomen. To suppress motion artifacts due to respiratory corruption, a phase-reordering technique was introduced so that the low frequency components of the phase data were obtained first during the imaging period. Image quality and degree of motion suppression were assessed by four radiologists independently without information on breath-holding time. Abnormalities were detected in 30 cases (93.8%), and their extent was correctly assessed in 28 cases (87.5%). More confident assessment was possible in abnormalities of the pulmonary vessels and thoracic aorta than in those of the abdominal aorta and portal venous system. With phase reordering, more than 20 seconds of breath-holding ensured image quality sufficient to correctly assess the vascular abnormalities. While this technique is easy and requires only single breath-holding, it can provide excellent MRA without slice-to-slice spatial misregistration.
Aortic Aneurysm, Abdominal↗
Cross-species transplantation of photoreceptors with tacrolimus hydrate (FK506) treatment.
Photoreceptors from normal neonatal or transgenic neonatal mice with normally developing retinas were transplanted into the subretinal spaces of normal rats. The animals with transplants received either immunosuppressive treatment with tacrolimus hydrate for the first two weeks after transplantation or no treatment. At 4 weeks after transplantation, graft survival occurred only in rats treated with tacrolimus. In 7 of the 12 treated eyes, photoreceptors survived at least 4 weeks after transplantation. Relatively mature outer segments were found only in 2 eyes in which the retinal grafts formed rosettes.
Animals↗
Identification of the 65-kDa phosphoprotein in murine macrophages as a novel protein: homology with human L-plastin.
We demonstrated that a 65-kDa cytosolic protein (pp65) was most heavily phosphorylated in murine macrophages in response to bacterial lipopolysaccharide (J. Immunol. 146:3617, 1991). The pp65 phosphorylation closely correlated with cellular responses in the macrophages. We have thus performed amino acid sequence analysis of the two pp65-derived peptide fragments in order to elucidate its structure and function. The results indicated that pp65 is a novel protein existing almost exclusively in hemopoitetic cells and has the strong homology with human L-plastin, a substrate which has recently been identified as a novel protein transformation-dependently expressed in neoplastic human cells. Our pp65 is apparently the first purified protein whose phosphorylation has been augmented by stimulation with bacterial lipopolysaccharide and whose primary structure has been clarified. Because L-plastin possesses the unique functional domains, detailed investigation of the pp65 phosphorylation should lead to progress in our understanding of the mechanisms of macrophage activation.
Amino Acid Sequence↗
Simultaneous determination of deflazacort metabolites II and III, cortisol, cortisone, prednisolone and prednisone in human serum by reversed-phase high-performance liquid chromatography.
A new high-performance liquid chromatographic method for the analysis of human serum from subjects administered prednisolone or deflazacort has been established. Two deflazacort metabolites (metabolites II and III), prednisolone and its metabolite (prednisone), as well as cortisol and cortisone in human serum were analyzed simultaneously. These six compounds and the internal standard, betamethasone, were extracted from 1 ml of human serum using a Sep-Pak Plus Environmental C18 column and then separated on a Hypersil ODS (25 x 0.46 cm I.D.) column using a gradient system. The lower limit of quantitation for each compound was 10 ng/ml based on signal-to-noise ratio of 5 and calibration curve linearity. Within-day and between-day validations gave a coefficient of variation of less than 10% and a relative error of ca. 10% (n = 11).
Anti-Inflammatory Agents↗
Expression and characterization of an inositol 1,4,5-trisphosphate binding domain of phosphatidylinositol-specific phospholipase C-delta 1.
It was previously found that the 85-kDa protein purified from rat brain using an inositol 1,4,5-trisphosphate (Ins(1,4,5)P3)-immobilized matrix was the delta 1 isoform of phosphatidylinositol-specific phospholipase C (PLC). We expressed rat PLC-delta 1 in Escherichia coli as a fusion protein with glutathione S-transferase, and found that the bacterial lysate shows a significant amount of Ins(1,4,5)P3 binding. The lysate was applied to Ins(1,4,5)P3-immobilized column chromatography and the eluate with 2 M NaCl solution containing only a 100-kDa protein showed high Ins(1,4,5)P3 binding. The lysate was also purified to near homogeneity using a glutathione-Sepharose 4B affinity system. Bacterially-expressed enzyme thus purified showed essentially the same inositol phosphate binding characteristics as the brain-derived enzyme. PLC-delta 1 consists of the amino-terminal nonconserved region and two well-conserved regions among isozymes, designated as X and Y, which are thought to constitute a catalytic core of the enzyme. Using a combination of deletion mutants and proteolytic products of the enzyme, we were able to locate an Ins(1,4,5)P3 binding domain in the molecule. Deletion of 223 residues from the amino terminus completely abolished the binding activity, while deletion of X region only partially inhibited the binding and deletion of Y region did not affect the binding. A 76-kDa proteolytic product of the expressed PLC-delta 1 which lacked 60 amino acids at the amino terminus showed a minimal Ins(1,4,5)P3 binding activity. A peptide consists of 14 amino acids corresponding to residues 30-43 of PLC-delta 1, which contains 6 basic amino acids, binds to an Ins(1,4,5)P3-immobilized matrix. Moreover, Ins(1,4,5)P3 binding was blocked by phospholipid vesicles containing phosphatidylinositol 4,5-bisphosphate. These results, taken together, indicate that the amino-terminal domain of PLC-delta 1 is important for the binding of both Ins(1,4,5)P3 and phosphatidylinositol 4,5-bisphosphate.
Amino Acid Sequence↗
Changes in lipid peroxidation, Cu/Zn-superoxide dismutase and its mRNA following an intracerebroventricular injection of 6-hydroxydopamine in mice.
A single i.c.v. injection of 6-hydroxydopamine (6-OHDA) in mice resulted in a biphasic increase in lipid peroxidation as assayed by the level of thiobarbituric acid-reacting substances (TBARS). An increase in Cu/Zn-superoxide dismutase (SOD) activity was temporally related with the first peak of TBARS but remained unchanged during the second TBARS peak. This suggests that a free radical species other than O2- may be involved in the late onset increase in TBARS. The level of Cu/Zn-SOD mRNA did not immediately reflect the change in Cu/Zn-SOD activity but rather increased gradually reaching significantly higher levels only 8 weeks after i.c.v. an injection of 6-OHDA. This increase in Cu/Zn-SOD mRNA likely occurs in response to a consumption of intrinsic SOD. Thus, short- and long-term increases in lipid peroxidation likely occur by different mechanisms and studies of both are needed to elucidate the neurodegenerative process.
Animals↗
Purification and reconstitution of an intestinal Na(+)-dependent neutral L-alpha-amino acid transporter.
Using an improved reconstitution method, we have purified an Na(+)-dependent neutral L-alpha-amino acid transporter from rabbit small intestine to apparent homogeneity. The preparation solubilized with octaethylene glycol dodecyl ether (C12E8) was purified by successive chromatographies on DEAE-Toyopearl and lentil lectin-Sepharose 4B columns. The transport activity was assayed by reconstitution of the protein into liposomes. The specific activity of the final preparation was 1364-fold that of brush border membrane vesicles. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the active fractions gave one band of 90 kDa. Kinetic analysis using proteoliposomes reconstituted with the purified fraction showed that alanine transport was mediated by high affinity system with Kt value of 0.19 mM and Jmax value of 2.8 nmol/mg protein/s. Analysis of the amino acid composition of the purified transporter revealed that the transporter is very hydrophobic protein. From its specific activities for transport of individual amino acids this transporter was concluded to possess broad specificity for neutral L-alpha-amino acids. Furthermore, inhibition study of other amino acids allowed us to identify this transport pathway as the intestinal system B.
Amino Acid Transport Systems↗
Amphiphilic peptides enhance the efficiency of liposome-mediated DNA transfection.
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Amino Acid Sequence↗
Effect of vagotomy on hyperactivity and increased dopamine turnover induced by intraperitoneal administration of thyrotropin-releasing hormone.
Thyrotropin-releasing hormone (TRH) injected intraperitoneally at doses of 10 mg/kg and 20 mg/kg induced marked hyperactivity in rats. Although regional levels of brain dopamine and its metabolites (DOPAC and HVA) in vagotomized rats did not differ from those in sham-operated controls, the (DOPAC + HVA)/dopamine ratio, an indicator of dopamine turnover, was significantly higher in the nucleus accumbens of TRH-treated sham-operated rats than that in untreated sham-operated controls. TRH injection induced hyperactivity only in sham-operated rats and not in subdiaphragmatic bilaterally vagotomized rats. Similarly, bilateral vagotomy completely abolished the TRH-induced increases in dopaminergic turnover in the nucleus accumbens. These results suggest that the dopaminergic system in the nucleus accumbens is involved in hyperactivity induced by TRH, and that TRH mainly affects peripheral receptors. The vagal nerve may be the major pathway from the visceral organs to the brain involved in the etiology of hyperactivity.
3,4-Dihydroxyphenylacetic Acid↗
Effect of calcium on the mobility of gamma-chain from fibrinogen Osaka V on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
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Calcium↗
A surface-coil-type resonator for in vivo ESR measurements.
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Electron Spin Resonance Spectroscopy↗
An analysis of bacteraemia in a university hospital in Japan over a 10-year period.
Details of positive blood cultures obtained from 357 inpatients attending the Toyama University Hospital were collected over a 10-year period in order to document changes in microbiological and clinical features of bacteraemia. Fifty-one per cent of patients were over 60 years old, 48% had intravascular catheters in-situ, and 17% had had surgical procedures within 30 days prior to the isolation of organisms from the blood. The proportion of underlying diseases other than malignancies increased over the 10-year period (42-60%, P < 0.05). Patients from surgical departments other than the Academic Department of Surgery increased over the study period (16-55%, P < 0.05). Staphylococcus aureus bacteraemia increased significantly (29 to 49%, P < 0.05) as did pseudomonas and anaerobic bacteraemia. Most bacteria showed no significant changes in their antibiotic sensitivity pattern over the 10 years. Clinical features in patients with bacteraemia varied with the infective organisms and the underlying disease. Mortality was high in patients with haematological malignancy, usually in association with Pseudomonas aeruginosa.
Adolescent↗
Renal protective effect of efonidipine hydrochloride (NZ-105), a new calcium antagonist, in spontaneously hypertensive rats.
1. We investigated the renal protective effect of efonidipine hydrochloride (NZ-105) in spontaneously hypertensive rats (SHR). SHR were given a diet containing 0.075% NZ-105 from 8 weeks old for 20 weeks. 2. 24-hr urinary protein excretion in the control SHR (drug-free diet) increased with age (from 77.3 mg/kg/day at 8 weeks old to 385.4 mg/kg/day at 28 weeks old), while that in NZ-105-treated SHR was maintained at almost the same level as that in Wistar-Kyoto rats (WKY), matched control animals throughout the experimental period. 3. The histological changes of the kidney were examined by light microscopy at the end of the treatment period. In control SHR, swelling and hyalinization of glomeruli, dilatation of renal tubules containing hyaline casts and arteriolosclerosis were revealed. The long-term administration of NZ-105 markedly suppressed these changes. 4. The kidney weights and plasma creatinine concentration in control SHR were higher than those in WKY, while they were significantly reduced in NZ-105-treated SHR. The long-term administration of NZ-105 also suppressed the elevation of systolic blood pressure and the increases of plasma renin activity and aldosterone concentration. 5. These findings suggest that NZ-105 inhibits the development of proteinuria and progressive kidney damage in SHR and may become a useful antihypertensive drug with the renal protective effect.
Animals↗
Molecular cloning of two new heat shock genes related to the hsp70 genes in Staphylococcus aureus.
We have identified two new heat shock protein genes, orf37 and orf35, in Staphylococcus aureus, located upstream and downstream of grpE(hsp20), dnaK(hsp70), and dnaJ(hsp40) homologous genes in the order orf37-hsp20-hsp70-hsp40-orf35. The transcripts of both orf37 and orf35 were increased by thermal upshift of the culture from 37 to 46 degrees C. The heat shock promoters were located upstream of orf37 and upstream of hsp40. The deduced peptide of orf37 showed similarity with those of orfA in Clostridium acetobutylicum and orf39 in Bacillus subtilis. orf35 was unique in S. aureus and has not yet been described in other bacteria.
Amino Acid Sequence↗