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Biomedical subjects

N Hirata

Publications and source records attributed to N Hirata.

At least 19 recordsLinked to original sources

Detailed images of asteroid 25143 Itokawa from Hayabusa.

Rendezvous of the Japanese spacecraft Hayabusa with the near-Earth asteroid 25143 Itokawa took place during the interval September through November 2005. The onboard camera imaged the solid surface of this tiny asteroid (535 meters by 294 meters by 209 meters) with a spatial resolution of 70 centimeters per pixel, revealing diverse surface morphologies. Unlike previously explored asteroids, the surface of Itokawa reveals both rough and smooth terrains. Craters generally show unclear morphologies. Numerous boulders on Itokawa's surface suggest a rubble-pile structure.

Journal Article↗

The rubble-pile asteroid Itokawa as observed by Hayabusa.

During the interval from September through early December 2005, the Hayabusa spacecraft was in close proximity to near-Earth asteroid 25143 Itokawa, and a variety of data were taken on its shape, mass, and surface topography as well as its mineralogic and elemental abundances. The asteroid's orthogonal axes are 535, 294, and 209 meters, the mass is 3.51 x 10(10) kilograms, and the estimated bulk density is 1.9 +/- 0.13 grams per cubic centimeter. The correspondence between the smooth areas on the surface (Muses Sea and Sagamihara) and the gravitationally low regions suggests mass movement and an effective resurfacing process by impact jolting. Itokawa is considered to be a rubble-pile body because of its low bulk density, high porosity, boulder-rich appearance, and shape. The existence of very large boulders and pillars suggests an early collisional breakup of a preexisting parent asteroid followed by a re-agglomeration into a rubble-pile object.

Journal Article↗

Effects of thiopental on bispectral index and heart rate variability.

BACKGROUND AND OBJECTIVE: Thiopental has been reported to reduce sympathetic tone, however, it is not clear whether change in heart rate variability is associated with depth of anaesthesia. The purpose of the present study was to evaluate changes in heart rate variability at different depths of hypnosis during induction of anaesthesia with thiopental. METHODS: We studied 17 ASA I patients scheduled for minor surgery. The depth of hypnosis was monitored by the BIS. Spectral analysis of heart rate variability using a maximum entropy method resulted in a characteristic power spectrum with two main regions, a high frequency and a low frequency. Haemodynamics, entropy, low frequency, high frequency and low frequency/high frequency were monitored in an awake state and after the induction of anaesthesia. RESULTS: Heart rate increased in a BIS-dependent manner, whereas blood pressure showed no significant changes during the study period. High frequency, entropy and low frequency decreased with a reduction in the BIS value. Low frequency/high frequency showed no significant change during the study period. CONCLUSIONS: Induction of anaesthesia with thiopental increased heart rate and decreased high frequency, entropy and low frequency in a BIS-dependent manner, indicating that thiopental reduces cardiac parasympathetic tone depending on the depth of hypnosis.

Adult↗

Engineering of a novel ruthenium sensitizer and its application in dye-sensitized solar cells for conversion of sunlight into electricity.

A novel ligand 4,4'-bis(carboxyvinyl)-2,2'-bipyridine (L) and its ruthenium(II) complex [Ru(II)L(2)(NCS)(2)] (K8) were synthesized and characterized by analytical, spectroscopic, and electrochemical techniques. The performance of the K8 complex as a charge transfer photosensitizer in nanocrystalline TiO(2) based solar cells was studied. When the K8 complex anchored onto a nanocrystalline TiO(2) film, we achieved very efficient sensitization yielding 77 +/-5% incident photon-to-current efficiencies (IPCE) in the visible region using an electrolyte consisting of 0.6 M methyl-N-butyl imidiazolium iodide, 0.05 M iodine, 0.05 M LiI, and 0.5 M 4-tert-butylpyridine in a 50/50 (v/v) mixture of valeronitrile and acetonitrile. Under standard AM 1.5 sunlight, the complex K8 gave a short circuit photocurrent density of 18 +/- 0.5 mA/cm(2), and the open circuit voltage was 640 +/- 50 mV with fill factor of 0.75 +/- 0.05, corresponding to an overall conversion efficiency of 8.64 +/- 0.5%.

Journal Article↗

Minimally invasive direct coronary artery bypass for completely obstructed left anterior descending coronary artery.

BACKGROUND: We evaluated the efficacy of minimally invasive direct coronary artery bypass (MIDCAB) using the left internal thoracic artery (LITA) in patients with completely obstructed left anterior descending coronary artery (LAD). METHODS: Ten patients undergoing MIDCAB for LAD stenosis were enrolled in this study. These patients were all men aged 45 to 69 years, and were divided into two groups, one showing complete LAD obstruction (n=5, Group A), and one about 90% stenosis of the LAD (n=5, Group B). RESULTS: The internal size of the LAD at the anastomosis site was significantly smaller in Group A than in Group B, and the time required for graft anastomosis in Group A was significantly longer. Total operation time, intubation time after operation, perioperative bleeding, total blood transfusion, max CK-MB, and hospital stay did not significantly differ between the two groups. Postoperative coronary angiography revealed good graft patency in both groups, however, one Group A patient had graft obstruction. CONCLUSIONS: The MIDCAB procedure appears useful even in our patients with completely obstructed LAD, despite the long anastomosis time. However, the indications for this procedure are limited by any perceived difficulty in harvesting the LITA by indirect vision or in performing the anastomosis based on the size or quality of the LAD. Intensive preoperative angiography evaluation is essential and conversion to a median full-sternotomy is necessary for cases in which we cannot confirm the feasibility of MIDCAB.

Aged↗

The role of substance P release in the lung with esophageal acid.

To investigate whether tachykinins are released in the airways by stimulating the esophagus, airway plasma extravasation induced by intraesophageal hydrochloric acid (HCl) in the presence or absence of the neutral endopeptidase (NEP) inhibitor phosphoramidon and the neurokinin-1-receptor antagonist FK888 was studied in anesthetized guinea pigs. Airway plasma extravasation also was studied in the presence of the NEP inhibitor in guinea pigs pretreated with capsaicin or bilateral vagotomy. Propranolol and atropine were used in all animals to block adrenergic and cholinergic nerve effects. Airway plasma leakage was evaluated by measuring extravasated Evans blue dye. One normal HCl infusion into the esophagus significantly increased plasma extravasation in the trachea. Phosphoramidon significantly potentiated plasma extravasation induced by HCl infusion into the esophagus in the trachea and main bronchi, and FK888 significantly inhibited extravasation in a dose-related manner. In capsaicin-treated animals, airway plasma extravasation was completely inhibited even in the presence of phosphoramidon. Tracheal plasma extravasation potentiated by phosphoramidon was significantly inhibited in the bilaterally vagotomized animals. These results suggest that locally acting substances are released by intraesophageal HCl stimulation that cause airway plasma extravasation. These substances are generated through activation of neural pathways, including some that traffic through the vagus nerves that link the esophagus or airways.

Animals↗

Minimally invasive surgery for lung cancer with coronary artery disease.

We report a 69-year-old woman with lung cancer and severe stenosis in the left anterior descending coronary artery. To perform a curative operation for the lung cancer without myocardial infarction, minimally invasive direct coronary artery bypass and left lower lobectomy with video-endoscopic assistance were performed simultaneously. There was no major complication, and she was discharged at 14 days after the operation. This procedure may be useful and safe for patients with lung cancer and coronary artery disease.

Adenocarcinoma↗

Ultrasonic integrated backscatter in early assessment of myocardial injury during open heart surgery.

OBJECTIVES: The recovery of cyclic variation of ultrasonic integrated backscatter in myocardial ischemia provides early assessment of myocardial injury and is useful in assessing myocardial injury during open heart surgery. METHODS: We studied 25 patients with valvular disease undergoing cardiac surgery--7 with aortic stenosis, 7 with aortic regurgitation, 6 with mitral stenosis, and 5 with mitral regurgitation. All underwent transesophageal echocardiography (before aortic cross-clamping: T-pre and 60 minutes after aortic declamping: T-60). The short-axis view at the papillary muscle level of the left ventricle was recorded and anterior areas were assessed. RESULTS: The magnitude of cyclic variation at T-pre and T-60 was 9.4 +/- 2.5 dB and 8.8 +/- 3.0 dB, and the ratio was 97 +/- 32%. Fractional shortening at T-pre and at T-60 was 27 +/- 7% and 20 +/- 9%, and the ratio was 79 +/- 44%. Recovery of magnitude was ahead of recovery of fractional shortening. The percent recovery of magnitude at T-60 did not correlate with aortic cross-clamping time (p = 0.91), postoperative peak creatine kinase-MB (p = 0.4), or catecholamine dosage (p = 0.13), but correlated with preoperative left ventricular mass index (p < 0.01). In patients with aortic stenosis, the percent recovery of magnitude at T-60 (66 +/- 4%) was significantly lower than in those with other types of valvular disease. CONCLUSIONS: The recovery of magnitude of cyclic variation of ultrasonic integrated backscatter provides early assessment of myocardial injury, particularly in severely hypertrophied hearts, during reperfusion after aortic declamping in open heart surgery.

Adult↗

Influence of cytoimmunological state on the development of tuberculosis in heart transplant recipients.

We examined the relationship between the development of tuberculosis and the cytoimmunological state of orthotopic heart transplant (HTx) recipients, which is affected by immunosuppressive therapy. Tuberculosis developed in 7 (1%) of 716 HTx recipients (four men and three women, aged 33-71 years) during a 7-year period, the standardized annualizing rate being about 1370/100000 per year, which is greater than the 17.5/100000 per year in the general population of Germany. Tuberculosis developed in the early posttransplant period in four patients when they were experiencing episodes of ongoing rejection, after 2.5, 3.5, 4.0, and 9.0 months, respectively, the standardized annualizing rate being 780/100000 per year. In three of those four patients, cytoimmunological monitoring was carried out until the development of tuberculosis. The repeated administration of pulsed corticosteroid therapy followed by oral steroids reduced T-cell and CD4+ T-cell counts, which could have increased the risk of tuberculosis developing if they were exposed. The cytoimmunological state of the remaining three patients in whom tuberculosis developed late after HTx, when episodes of ongoing rejection did not exist, was similar to the preoperative state, the standardized annualizing rate being 590/100000 per year. These findings indicate that the relatively high incidence of tuberculosis in post-HTx patients could be attributable to the immunosuppressive therapy given, including steroids.

Adult↗

Association analysis of polymorphisms in the upstream region of the human dopamine D4 receptor gene (DRD4) with schizophrenia and personality traits.

The human dopamine D4 receptor (DRD4) is of major interest in molccular studies of schizophrenia and personality traits. We examined the association of schizophrenia and polymorphisms in the upstream region of the DRD4 gene (-768G>A in the negative modulator region; -521C>T, -376C >T, and -291C>T in the cell type-specific promoter region; and -616C>G between the two regions) in 208 schizophrenic patients and 210 normal controls. No significant difference in genotype and allele frequencies was observed between the two groups, indicating that these polymorphisms do not make a major contribution to the pathogenesis of schizophrenia. We also studied the association of polymorphisms in the upstream region and a 48-bp repeat polymorphism in exon III of the DRD4 gene with personality traits in 173 Japanese individuals who completed the temperament and character inventory (TCI). The -768G>A polymorphism was significantly associated with reward dependence (P= 0.044), while no significant association was observed between novelty seeking and polymorphisms in the upstream region or the exon III repeat polymorphism of the DRD4 gene.

Base Sequence↗

Dyspnoea and hyperventilation induced by synthetic progesterone chlorpromadinone acetate for the treatment of prostatic hypertrophy.

We describe a 74-year-old patient with dyspnoea and tachypnoea induced by chlorpromadinone acetate, a synthetic progesterone used to treat prostatic hyperplasia. The dyspnoea, tachypnoea and hypocapnia improved after discontinuing the chlorpromadinone acetate. It is important to recognize that synthetic progesterones can cause dyspnoea and hyperventilation.

Acetates↗

Association study of polymorphisms in the GluR5 kainate receptor gene (GRIK1) with schizophrenia.

The glutamatergic dysfunction hypothesis suggests genes involved in glutamatergic transmission as candidates for schizophrenia susceptibility genes. We screened single nucleotide polymorphisms (SNPs) in the entire coding sequence of the GluR5 kainate receptor gene, GRIK1, by polymerase chain reaction-single strand conformation polymorphism and direct sequencing. We identified six SNPs including three known ones, 522A/C (174T, synonymous), 1173C/T (391D, synonymous), and 2705C/T (902L/S), as well as three novel ones, 995C/T (332A/V), 2400C/T (800L, synonymous), and 2585A/G (862R/Q). We genotyped Japanese samples of schizophrenia (n = 193-203) and healthy controls (n = 199-215) for three SNPs those were commonly observed in our samples, 522A/C, 1173C/T, and 2705C/T. We observed no significant associations of the SNPs and their haplotypes with schizophrenia. Therefore, we conclude that GRIK1 does not play a major role in schizophrenia pathogenesis in the Japanese population.

Base Sequence↗

[Clinical characterization of blaIMP positive gram-negative rods isolated cases].

We detected the metallo-beta-lactamase gene blaIMP positive strains of the gram-negative rods (GNR) isolated in Oita Medical University Hospital between 1993 and 1999 and studied the clinical characteristics of patients infected or colonized with blaIMP positive GNR. 25 strains (20 Pseudomonas aeruginosa and 5 Serratia marcescens) were detected and most of them were isolated from urinary samples after 1997. In the studies of antimicrobial susceptibility, some strains had sensitivity to aztreonum or imipenem although most of the strains showed multidrug resistance. When blaIMP positive GNR were isolated from patients, these strains were thought to have caused infection in 88% of the patients. About half of the patients were over 65 years old and had malignant diseases. Most of the patients had inserted urinary tract catheters, intratracheal tube or intravernous catheters. It was suggested that the insertion of the catheters were related to infection of blaIMP positive GNRs. Two patients were not treated with any antibiotics before the isolation of blaIMP positive GNRs although more than half of the patients were administered carbapenems and cephems. Most of strains were isolated in the same department and showed the same genotype by pulsed field gel electrophoresis.

Bacterial Proteins↗

Pretreatment of mice with clindamycin improves survival of endotoxic shock by modulating the release of inflammatory cytokines.

Suppression of endotoxin release and subsequent production of inflammatory cytokines is crucial in the treatment of septic shock. We investigated the effect of clindamycin (CLI) on endotoxic shock induced in mice by Escherichia coli lipopolysaccharide (LPS). Mice were treated with CLI (160 to 600 mg/kg) or saline and then injected with E. coli LPS and D-(+)-galactosamine intraperitoneally 0.5 h after CLI administration. Pretreatment with CLI significantly improved survival in a dose-dependent manner (CLI, at 160, 300, and 440 mg/kg) and significantly lowered the peak concentrations of tumor necrosis factor alpha and interleukin-1beta (IL-1beta) in serum. However, the peak concentrations of IL-6 in the sera of CLI-treated mice were higher than in control mice. Our findings suggest that CLI alters LPS-induced inflammatory cytokine production and suppresses endotoxin-induced mortality in this murine model.

Animals↗

Occurrence of the major food allergen, ovomucoid, in human breast milk as an immune complex.

The major food allergen, ovomucoid (molecular weight of 28 kDa) could be detected in 12 of 37 human breast milk samples by using three types of enzyme-linked immunosorbent assay. By gel-filtration, ovomucoid in breast milk was only eluted in the fractions corresponding to a molecular weight of about 450 kDa, suggesting its occurrence as an immune complex with IgA. In fact, almost the same elution profile as that for ovomucoid was obtained for its immune complex with IgA by gel-filtration.

Adult↗

[Le Duc-Camey procedure as a method of ureteroileal implantation on augmentation cystoplasty in patients with myelodysplasia].

PURPOSE: We investigated the results of Le Duc-Camey procedure as a method of ureteroileal implantation on augmentation cystoplasty in patients with myelodysplasia. MATERIALS AND METHODS: A total of 14 patients (25 renal units) underwent ureteroileal implantation with Le Duc-Camey procedure on augmentation cystoplasty. The possible causes of complications concerning ureteroileal implantation that developed during the postoperative observation were classified as preoperative factors and postoperative factors.: The preoperative factors were the causative disease required ureteroneostomy, the grade of preoperative VUR, and the ureteral diameter at the anastomosis with the ileum.: The postoperative factors were the volume, and the compliance of the urinary bladder, and the maximum intravesical pressureled by the peristalsis of the utilized intestine. RESULTS: With the mean observation period of 31.6 months, no complications developed but VUR observed in 4 renal units of 4 patients. The patients with VUR had a larger ureteral diameter at the anastomosis site to the ileum among the preoperative factors and a significantly larger maximum intravesical pressure led by the intestinal peristalsis among the postoperative factors when compared with the patients without VUR. CONCLUSION: Regarding ureteroileal implantation with Le Duc-Camey procedure on augmentation cystoplasty in patients with myelodysplasia. It seems necessary to consider some countermeasures for the dilated ureters and for the unexpected 2 elevation of intravesical pressure due to the peristalsis of the utilized intestine.

Adolescent↗

[Prevalence of asthma in adults in Menda town rural-mountain area in Japan].

Several reports have suggested that the prevalence of asthma in adults is currently increasing. However, recent prevalence of asthma has not reported in Japan, especially in rural-mountain areas. To investigate the prevalence of asthma in adults in Japan, we conducted clinical epidemiological research on 5066 inhabitants of Menda town, in a rural-mountain area of Japan. The study population comprised 98.7% of adults in the town, including senior high school students whose age were more than 15 years old. The prevalence of asthma among adults was 3.6%. The ratio of prevalence in males to prevalence in females was 1.44. Peaks prevalences were observed in the age ranges of 15-19 and > 70 years old in males, and 15-19, 40-49 and > 70 years old in females.

Adolescent↗