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Biomedical subjects

T Hirayama

Publications and source records attributed to T Hirayama.

At least 145 records · Page 8Linked to original sources
PubMed1996

IL-6 mRNA synthesis by peripheral blood mononuclear cells (PBMC) in patients with chronic renal failure.

We measured levels of IL-6 mRNA in PBMC obtained from patients with chronic renal failure, using polymerase chain reaction (PCR). PBMC were isolated from 45 patients on haemodialysis (HD) at the start of HD. PBMC were also isolated from 35 patients on HD at the end of HD, 23 patients on continuous ambulatory peritoneal dialysis (CAPD), 24 undialysed patients with chronic renal failure (CRF), and 19 healthy controls. Total RNA was extracted from PBMC with RNA zol and reverse transcribed into cDNA. To prepare samples containing identical amounts of beta-actin cDNA, we performed competitive PCR by co-amplifying serial dilutions of mutant templates containing a single point mutation which generated a unique Eco RI site. Next, to measure IL-6 cDNA semiquantitatively in the samples containing identical amounts of beta-actin (100 pg), we performed PCR amplification using 2 fg of the IL-6 mutant template containing a unique Eco RI site. Higher levels of IL-6 mRNA in the PBMC were observed in the HD patients than in the CAPD patients and healthy controls. The levels of IL-6 mRNA in the PBMC at the end of HD were not significantly higher than those at the start of HD. These results suggest that the dialysis session itself did not significantly affect IL-6 mRNA levels in the PBMC, but that chronic stimulation by maintenance HD may be associated with higher levels of IL-6 mRNA observed in HD patients.

Adult↗
PubMed1996

Characteristics of the pituitary gland in elderly subjects from magnetic resonance images: relationship to pituitary hormone secretion.

OBJECTIVE: Physiological changes in the pituitary gland with age have not been fully evaluated. The aim of this study was to clarify the morphological characteristics of the pituitary gland by magnetic resonance imaging(MRI) in elderly subjects and to relate them to pituitary hormone secretion. DESIGN AND PATIENTS: We investigated the pituitary MRI in 59 elderly (15 males, 44 females; median 82 years) and 41 young (13 males, 28 females; median 34 years) healthy subjects. RESULTS: Pituitary height, width and volume in the elderly subjects were less than those in the young subjects. Empty sella was more frequently observed in the elderly subjects (19%), especially women, than in the young ones. However, no relation was observed between the pituitary size or volume and basal levels of anterior pituitary hormones. Posterior pituitary bright signal(PBS) on T1-weighted MRI, which is thought to reflect its storage of the neurophysin-peptide complex, was not detected in 29% of the elderly subjects while it could be detected in all the young subjects. None of the elderly subjects showed clinical signs or symptoms of diabetes insipidus. Fasting plasma osmolarity and AVP in the elderly subjects were significantly higher than in the young subjects. Moreover, plasma AVP was significantly higher in the elderly subjects without the PBS than in those with the PBS. CONCLUSIONS: It is suggested that the excessive release of AVP from the posterior pituitary as a result of persistently raised plasma osmolality in the elderly subjects may lead to depletion of the neurosecretory granules in the posterior pituitary gland and may result in disappearance of the posterior pituitary bright signal on T1-weighted MRI. As these morphological changes might relate to the normal physiological occurrence of ageing, we should be cautious in evaluating MRI of the pituitary gland in elderly subjects.

Adrenocorticotropic Hormone↗
PubMed1996

Evaluation of susceptibility of gram-positive and -negative bacteria to human defensins by using radial diffusion assay.

Defensins are small cationic bactericidal peptides present abundantly in the granules of polymorphonuclear neutrophils (PMNs). Human PMNs contain four defensins termed HNP-1 to HNP-4. We used a new assay system in agar plates, the radial diffusion assay, to evaluate the effects of human defensins against gram-positive and -negative bacteria. A crude mixture of HNP-1, -2, and -3 (crude HNPs) was purified from human PMN extracts by reversed-phase high-pressure liquid chromatography (RP-HPLC). The different components were later separated by RP-HPLC and gel permeation chromatography. We compared the antibacterial activities of purified HNP-1, -2, and -3 against Escherichia coli, Pseudomonas aeruginosa, methicillin-susceptible Staphylococcus aureus, and methicillin-resistant S. aureus strains using the radial diffusion assay. The antibacterial activities of HNP-1 and HNP-2 against all strains tested were similar to those of the crude HNPs, but the activity of HNP-3 was less than those of the other defensins. To quantitate the activities of HNPs against different bacteria, we defined the minimal dose of crude HNPs forming a detectable clear zone around the bacteria as the minimal inhibitory dose (MID) and determined the MIDs for 10 strains of E. coli, 12 strains of P. aeruginosa, 10 strains of methicillin-susceptible S. aureus, and 12 strains of methicillin-resistant S. aureus isolates, including clinical isolates. In general, the MIDs of the HNPs were similar against similar bacterial species. However, the MIDs for P. aeruginosa were higher than those for the other organisms tested. The radial diffusion assay is suitable as a screening test for measuring the susceptibilities of isolates to defensins, because it is sensitive and simple and has good reproducibility.

Anti-Bacterial Agents↗
PubMed1996

Identification of ligand recognition sites in heat-stable enterotoxin receptor, membrane-associated guanylyl cyclase C by site-directed mutational analysis.

Guanylyl cyclase C (STaR), a receptor protein for heat-stable enterotoxin (STa) elaborated by Escherichia coli, is associated with and spans the plasma membrane of mammalian intestinal cells. The extracellular domain functions in the binding of STa and the association of each domain to an oligomeric form. Two amino acid residues, Arg-136 and Asp-347, were identified as the residues binding to STa in the extracellular domain of pig STaR by site-directed mutagenesis and analysis of expression on 293T cells. Replacement of these residues by other amino acid residues resulted in the loss of binding of pig STaR to STa, and as a result, STa-induced guanylyl cyclase activity was eliminated. Furthermore, mutation in a region (from Asp-347 to Val-401) which is close to the transmembrane domain caused a significant reduction in both STa-binding activity and guanylyl cyclase catalytic activity. These results suggest that the region adjacent to the transmembrane domain plays an important role in facilitating a favorable conformation of STaR for STa binding.

Animals↗
PubMed1996

A classical strain of Vibrio cholerae with diminished ability to process the proteolytically sensitive site in the A subunit of cholera toxin.

Vibrio cholerae O1, No. 31, a strain isolated from a patient with mild diarrhea, produced mainly the unnicked cholera toxin. The amount of toxin that had accumulated in the cells was approximately 200 times lower than that secreted into the culture medium. When the unnicked toxin was purified by three successive column chromatographies and then extracted from the polyacrylamide gel, the unnicked toxin showed two bands corresponding to the A and B subunits by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the A1 fragment was detected by trypsinization. Biological and enzymatic activities of the purified toxin with trypsinization were identical to those of cholera toxin from V. cholerae 569B as seen in the rabbit skin permeability test and the NAD:agmatine ADP-ribosyltransferase assay. DNA sequences of the A and B subunits were identical to those of the A- and B-subunit genes from the El Tor 2125 and classical 0395 strains, respectively. These data suggest that the wild V. cholerae strain, No. 31, produces a toxin identical to toxins previously reported in the literature and secretes it without accumulation in the cell, as is the case with other strains. However, strain No. 31's ability to nick the toxin is diminished compared with such abilities of other strains.

Animals↗
PubMed1996

[Study of the usefulness of a kit containing imipenem/cilastatin powder with diluent for injection: convenience of use and preparation].

The usefulness of a newly developed imipenem/cilastatin powder-and-diluent kit packed in non-glass container was compared to that packed in commercially available glass vials. The imipenem/cilastatin powder-and-diluent kit container is made of a polyolefin bag with two chambers that contain imipenem/cilastatin powder and diluent (0.9% saline, 100 ml), respectively. The convenience of use of the kit and the time required for the preparation of the dosing solution were evaluated by nurses and pharmacists at the Kitasato University East Hospital. The newly developed kit received higher scores with regard to convenience of use and led to a 46 approximately 59% reduction in the time required for preparation as compared to the commercially available glass vials.

Cilastatin↗
PubMed1996

[Study of the usefulness of a kit containing imipenem/cilastatin powder with diluent for injection: accuracy of reconstitution].

The usefulness of a kit consisting of non-glass packaging was evaluated in terms of accuracy of reconstitution. The newly developed imipenem/cilastatin powder-and-diluent kit consists of a polyolefin bag with two chambers that contain impenem/cilastatin powder and diluent (0.9% saline, 100 ml), respectively. The accuracy of reconstitution was determined by nurse and pharmacists at the Kitasato University East Hospital by measuring the amount of materials remaining in vials after reconstitution using the syringe dilution method and the transfer-needle dilution method. The mean percent amounts of imipenem and cilastatin remaining after preparation by the syringe dilution method were 5.58 +/- 2.60% and 4.08 +/- 1.77%, respectively. The mean percent amounts of imipenem and cilastatin remaining after preparation by the transfer-needle dilution method were 3.99 +/- 2.28% and 3.71 +/- 2.09%, respectively. The amount of imipenem/cilastatin remaining in the newly developed kit should be negligible, because the kit serves as both a vial and a dosing package. Therefore, greater accuracy in terms of reconstitution is expected with the newly developed kit than with the traditional syringe dilution or transfer-needle dilution methods.

Cilastatin↗
PubMed1996

[Epileptic vertiginous seizure in a Japanese boy: a case report].

Dizziness in childhood is not an infrequent symptom, but epileptic vertigo is a rare condition in children. Here we report an 8-year-old Japanese boy with epileptic vertiginous seizures. At age 8 years, he visited Nippon Medical School Hospital because of a ten day history of dizziness. The dizziness occurred more than twenty times a day and he was hospitalized. On physical examination, the patient appeared normal and there were no abnormal neurological findings, including eye movement and cerebellar signs. Ophthalmoscopy, otoscopy, vestibular function test and hearing test were normal. Computerized tomography scanning and MR imaging of the head revealed no significant abnormality. The dizziness observed on admission comprised sudden brief attacks of rotatory sensation without amnesia regarding the event. Sometimes the attacks were accompanied by tremor like movement and numbness of the right hand, followed by postictal unsteadiness. Interictal EEG revealed spike-and-wave complexes in the central region dominantly in the light sleep stage. On ictal EEG, seizure discharges were observed to begin in the left central region and they increased in amplitude and subsequently propagated to the frontal and occipital regions. These findings were most suggestive of partial seizures. The patient was treated with carbamazepine and the seizures became well under control.

Anticonvulsants↗
PubMed1996

[Clinical study of tazobactam/piperacillin in obstetrics and gynecological infections].

A clinical study was carried out to investigate clinical efficacy and safety of tazobactam/piperacillin (TAZ/PIPC), a newly developed antibiotic agent for injections. The obtained results are as follows: 1. In 10 patients with obstetrics and gynecological infections (7 patients with endometrial infections, one patient with pelvic peritonitis, one patient with ovarian abscess and one patient with Bartholins's abscess) intravenous drip infusion of TAZ/PIPC, 5.0 g/day, was administered for 5 to 10 days. The total doses were 2550 g/body. 2. Clinical efficacy was evaluated in the above cases. As a result, an excellent result was obtained in one patient and good efficacies in 9 patients. The efficacy rate was 100% (10/10). Concerning the clinical bacteriological effect, eradication ratio was 83.3% (5/6). Concerning the bacteriological effect against 11 strains of clinical isolates, 4 strains were eradicated, 6 strains were replaced and one strain was unchanged. 3. Neither subjective/objective side effects nor abnormal laboratory test results were observed upon administration of TAZ/PIPC. These results suggested the usefulness of tazobactam/piperacillin in obstetrics and gynecological infections.

Adult↗
PubMed1995

Cloning and characterization of seven cDNAs for hyperosmolarity-responsive (HOR) genes of Saccharomyces cerevisiae.

Yeast cells can respond and adapt to osmotic stress. In our attempt to clarify the molecular mechanisms of cellular responses to osmotic stress, we cloned seven cDNAs for hyperosmolarity-responsive (HOR) genes from Saccharomyces cerevisiae by a differential screening method. Structural analysis of the clones revealed that those designated HOR1, HOR3, HOR4, HOR5 and HOR6 encoded glycerol-3-phosphate dehydrogenase (Gpd1p), glucokinase (Glk1p), hexose transporter (Hxt1p), heat-shock protein 12 (Hsp12p) and Na+, K+, Li(+)-ATPase (Ena1p), respectively. HOR2 and HOR7 corresponded to novel genes. Gpd1p is a key enzyme in the synthesis of glycerol, which is a major osmoprotectant in S. cerevisiae. Cloning of HOR1/GPD1 as a HOR gene indicates that the accumulation of glycerol in yeast cells under hyperosmotic stress is, at least in part, caused by an increase in the level of GPDH protein. We performed a series of Northern blot analyses using HOR cDNAs as probes and RNAs prepared from cells grown under various conditions and from various mutant cells. The results suggested that all the HOR genes are regulated by common signal transduction pathways. However, the fact that they exhibited certain distinct responses indicated that they might also be regulated by specific pathways in addition to the common pathways. Ca2+ seemed to be involved in the signaling systems. In addition, Hog1p, one of the MAP kinases in yeast, appeared to be involved in the regulation of expression of HOR genes, although its function seemed to be insufficient for the overall regulation of expression of these genes.

Adenosine Triphosphatases↗
PubMed1995

A gene encoding a phosphatidylinositol-specific phospholipase C is induced by dehydration and salt stress in Arabidopsis thaliana.

A cDNA corresponding to a putative phosphatidylinositol-specific phospholipase C (PI-PLC) in the higher plant Arabidopsis thaliana was cloned by use of the polymerase chain reaction. The cDNA, designated cAtPLC1, encodes a putative polypeptide of 561 aa with a calculated molecular mass of 64 kDa. The putative product includes so-called X and Y domains found in all PI-PLCs identified to date. In mammalian cells, there are three types of PI-PLC, PLC-beta, -gamma, and -delta. The overall structure of the putative AtPLC1 protein is most similar to that of PLC-delta, although the AtPLC1 protein is much smaller than PLCs from other organisms. The recombinant AtPLC1 protein synthesized in Escherichia coli was able to hydrolyze phosphatidylinositol 4,5-bisphosphate and this activity was completely dependent on Ca2+, as observed also for mammalian PI-PLCs. These results suggest that the AtPLC1 gene encodes a genuine PI-PLC of a higher plant. Northern blot analysis showed that the AtPLC1 gene is expressed at very low levels in the plant under normal conditions but is induced to a significant extent under various environmental stresses, such as dehydration, salinity, and low temperature. These observations suggest that AtPLC1 might be involved in the signal-transduction pathways of environmental stresses and that an increase in the level of AtPLC1 might amplify the signal, in a manner that contributes to the adaptation of the plant to these stresses.

Amino Acid Sequence↗
PubMed1995

Optimal dosage and differences in therapeutic efficacy of IGIV in Kawasaki disease.

In an initial study, three groups of patients with Kawasaki disease received either aspirin alone or alkylated immunoglobulin G intravenous preparation (IGIV) 200 mg/kg daily x 3 days + aspirin, or 400 mg/kg alkylated IGIV daily x 3 days + aspirin. In a second study, three groups of patients were treated with either 100, 200 or 400 mg/kg of native IGIV in combination with aspirin daily for 5 days. While the regimen of 200 mg/kg native IGIV daily x 5 days was found to be effective, the incidence of coronary artery lesions (CAL) was even less on a regimen of 400 mg/kg daily x 5 days. It is therefore suggested that a better therapeutic effect can be achieved with a 400 mg/kg dose of native IGIV. Based on the results from these two studies, it is assumed that native IGIV is more effective in inhibiting CAL formation and persistence than the chemically modified preparation in which the biological activity of the Fc region in the immunoglobulin G molecule is altered.

Aspirin↗
PubMed1995

Comparison of 5-hydroxytryptamine-induced contraction of rat pulmonary artery to that of aorta in vitro.

We investigated the nature of the contraction produced by 5-hydroxytryptamine (5-HT) in the rat pulmonary artery, and compared it with that produced in the rat aorta. Both ketanserin and ritanserin inhibited 5-HT-induced contraction in the pulmonary artery non-competitively. In contrast, ketanserin competitively antagonized the contraction in the aorta. Bunazosin, a selective alpha 1-blocker, partially inhibited 5-HT-induced contraction in the pulmonary artery, but not in the aorta. In both the pulmonary artery and aorta, 8-OH-DPAT, a 5-HT1A selective agonist, produced a concentration-dependent contraction. In the pulmonary artery, 5-HT and 8-OH-DPAT produced contractions with similar potencies. In contrast, 8-OH-DPAT was less potent than 5-HT in the aorta. Bunazosin inhibited 8-OH-DPAT-induced contraction in both vessels. However, pindolol, a 5-HT1A antagonist, did not inhibit 8-OH-DPAT-induced contraction in the pulmonary artery. These results suggest that 5-HT produces contraction via not only 5-HT2 receptor, but also non-5-HT2 receptor (probably alpha 1-adrenoceptor) in the rat pulmonary artery. Furthermore, 8-OH-DPAT does not activate the 5-HT1A receptor to produce a contraction, but does activate other receptors which interact with alpha 1-adrenoceptor.

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

The role of renal dopamine in the reduction of high blood pressure by beta 1-selective beta-blocker with intrinsic sympathomimetic activity in spontaneously hypertensive rats.

The present experiments were undertaken to clarify the difference of renal dopamine production from beta 1-selective beta-blocker with and without intrinsic sympathomimetic activity (ISA). Either beta-blocker with ISA, celiprolol (100 or 300 mg/kg/day; CEL-100 or CEL-300) or beta-blocker without ISA, atenolol (50 mg/kg/day; ATE-50) was administered to the SHR from 19 to 26 weeks. Degrees of lowering blood pressure in CEL-300 SHR and in ATE-50 SHR were similar, but decrease in heart rate was significantly less in CEL-300 SHR than in ATE-50 SHR. Urine output, which was significantly less in control SHR than in control WKY, was significantly greater in CEL-100 SHR and CEL-300 SHR, but not in ATE-50 SHR. Urinary excretions of noradrenaline (u-NA) and dopamine (u-DA) were significantly higher in control SHR than in control WKY and a comparable u-DA/u-NA ratio was found in these two groups. U-DA and the ratio of u-DA/u-NA were significantly elevated in CEL-100 SHR and CEL-300 SHR, but not in ATE-50 SHR. There was a significant positive correlation between u-DA/u-NA ratio and urine output and a significant negative correlation between the ratio of u-DA/u-NA and change of blood pressure in control SHR, CEL-100 SHR and CEL-300 SHR. These results suggest that an enhancement of renal dopamine production by ISA (beta 2 stimulation) of beta 1-selective beta-blocker may contribute, at least in part, to the antihypertensive effect of this drug.

Adrenergic beta-1 Receptor Antagonists↗
PubMed1995

[Factors influencing users' destination upon discharge from a geriatric intermediate care facility in an urban area].

Geriatric Intermediate Care Facilities (GICF) have been established to help the hospitalized elderly return home. Users of the GICF are elderly persons who do not need hospitalization, but are mentally or physically impaired. To determine what factors influence users' destinations upon discharge from GICF, we analyzed various characteristics such as age, sex, place of residence before admission, length of stay, intellectual impairment, ability to perform activities of daily living (ADL) among users (N = 389) in a GICF in Chiba City. Multiple logistic regression analyses revealed that, compared with the users who were hospitalized, users who were male, admitted for home, stayed for long periods, and had a high ability to perform ADL were more likely to return home. The analyses also revealed that, compared with the users who were institutionalized, users who came from home, stayed for short periods, and had a high ability to perform ADL were more likely to return home. Evaluating a user's physical, mental, and socioeconomical conditions at an early stage of admission to a GICF may allow us to predict whether the user can be successfully discharged to his or her home or will have to remain at the GICF for an extended period.

Activities of Daily Living↗