Biomedical subjects

K Hayashi

Publications and source records attributed to K Hayashi.

At least 19 recordsLinked to original sources

PubMed2007

Epigenetic regulation for the induction of meiosis.

The germ cell lineage is the sole cell lineage through which genomic information is transmitted into successive generations. To this end, germ cells undergo various specific differentiation steps including meiosis, whose regulation seems to correlate closely with fundamental mechanisms that create differences between germ cells and somatic cells. In mammals, meiosis is triggered by extra-embryonic stimuli such as retinoic acid, which may induce various intracellular molecular cascades promoting meiosis. In addition, the specific epigenetic status arranged in germ cells before and after induction of meiosis, including meiosis-specific transcription control based on histone methylation by a novel histone methyltransferase Meisetz, is also critical for its proper progression.

Animals↗

PubMed2007

Interferon-beta and adhesion molecules (E-selectin and s-intracellular adhesion molecule-1) are detected in sera from patients with retinal vasculitis and are induced in retinal vascular endothelial cells by Toll-like receptor 3 signalling.

Retinal vasculitis is a major component of ocular inflammation that plays a role in retinal tissue damage in patients with idiopathic uveitis and Behçet's disease. Here we show that type 1 interferons (IFN alpha/beta) were not detected in sera from normal individuals but were identified in up to 46% of the sera from retinal vasculitis patients. The predominant form of IFN observed was IFN-beta, which was detected in 39% of Behçet's disease patients and 47% of idiopathic uveitis patients. Seven patients whose sera contained IFN-beta were monitored prospectively. IFN-beta was shown to be present for 6-12 months in all seven of the sera samples tested. Furthermore, the adhesion molecule profile identified in this study was strikingly different when Behçet's and uveitis patient sera were compared to sera from normal controls. Sera from Behçet's disease patients contained significantly elevated levels of the soluble adhesion molecules, sE-selectin and s-intracellular adhesion molecule-1 (sICAM-1), whereas sera from patients with idiopathic uveitis contained significantly increased sE-selectin. In vitro studies evaluating the cell source of these cytokines revealed that polyriboinosinic polyribocytidylic acid (poly I:C) activated retinal vascular endothelial cells produce sE-selectin, sICAM-1 and IFN-beta. Production of these molecules was inhibited by pretreatment with anti-Toll-like receptor 3 (TLR-3) antibody. In conclusion, IFN-beta, sE-selectin and sICAM-1 are elevated in patients with retinal vasculitis and are induced in retinal vascular endothelial cells in vitro by activating the innate immune system through TLR-3. Further analysis of innate immune signalling may prove to be a novel target for future studies on pathogenic mechanisms and therapeutic approaches in retinal vasculitis.

Acute Disease↗

PubMed2006

Extravascular lung water measured using single transpulmonary thermodilution reflects perioperative pulmonary edema induced by esophagectomy.

Pulmonary edema is the most frequent postoperative complication following esophagectomy for thoracic esophageal cancer. We enrolled 23 patients who underwent esophagectomy with extended lymph node dissection for thoracic esophageal cancer in a prospective observational clinical trial. We used the PiCCO device to measure extravascular lung water with the aim of determining whether it correlates with the respiratory index and whether it is predictive of pulmonary complications. Based on constant criteria, the tracheal tubes of 11 patients were removed on the morning of postoperative day 1 (extubation group), while 12 patients remained intubated (intubation group). These two groups significantly differed in that all patients in the extubation group recovered without any pulmonary complications, whereas 4 patients (33%) in the intubation group developed pulmonary complications. The extravascular lung water measured using PiCCO correlated significantly with the respiratory index. In the intubation group, both extravascular lung water and respiratory index were elevated 12 h after surgery and were even higher 24 h after surgery. The extravascular lung water measured using PiCCO reflects the level of postoperative pulmonary edema and predicts the pulmonary complications induced by esophagectomy with extended lymph node dissection.

Aged↗

PubMed2006

Comparison of posterior capsule opacification between fellow eyes with two types of acrylic intraocular lens.

PURPOSE: To compare the degree of posterior capsule opacification (PCO) and visual function between fellow eyes that received two different types of hydrophobic acrylic intraocular lenses (IOLs). METHODS: Forty-five patients underwent bilateral phacoemulsification and implantation of an Alcon AcrySof IOL (MA60AC) in one eye and an AMO Sensar IOL (AR40e) in the fellow eye. The PCO density value was measured using the Scheimpflug videophotography system at 1, 6, 12, and 24 months after surgery. The incidence of eyes that required a neodymium:YAG (Nd:YAG) laser capsulotomy, visual acuity, and contrast sensitivity with and without a glare source were also examined. RESULTS: The mean PCO value did not show a significant increase in either the AcrySof MA60AC or Sensar AR40e IOL groups, and was similar between the two groups throughout the 24-month follow-up period. The incidence of Nd:YAG laser capsulotomy was also the same between the groups. No significant difference was found in mean visual acuity between the two IOL groups during the follow-up, and there was no significant difference in photopic or mesopic contrast visual acuity with and without a glare source at 1 and 24 months after surgery. CONCLUSION: The degree of PCO in eyes with an AcrySof IOL are almost the same as that in eyes with a Sensar IOL, with the results that visual acuity and contrast sensitivity with and without glare are similar.

Acrylic Resins↗

PubMed2006

Global gene expression analysis in liver of obese diabetic db/db mice treated with metformin.

AIMS/HYPOTHESIS: Metformin is widely used as a hypoglycaemic reagent for type 2 diabetes. While the reduction of hepatic gluconeogenesis is thought to be a key effect, the detailed molecular mechanism of action of metformin remains to be elucidated. To gain insight into this, we performed a global gene expression profiling study. MATERIALS AND METHODS: We performed DNA microarray analysis to study global gene expression in the livers of obese diabetic db/db mice 2 h after a single administration of metformin (400 mg/kg). RESULTS: This analysis identified 14 genes that showed at least a 1.5-fold difference in expression following metformin treatment, including a reduction of glucose-6-phosphatase gene expression. The mRNA levels of glucose-6-phosphatase showed one of the best correlations with blood glucose levels among 12,000 genes. Enzymatic activity of glucose-6-phosphatase was also reduced in metformin-treated liver. Moreover, intensive analysis of the expression profile revealed that metformin effected significant alterations in gene expression across at least ten metabolic pathways, including those involved in glycolysis-gluconeogenesis, fatty acid metabolism and amino acid metabolism. CONCLUSIONS/INTERPRETATION: These results suggest that reduction of glucose-6-phosphatase activity, as well as suppression of mRNA expression levels of this gene, in liver is of prime importance for controlling blood glucose levels in vivo, at least at early time points after metformin treatment. Our results also suggest that metformin not only affects expression of specific genes, but also alters the expression level of multiple genes linked to the metabolic pathways involved in glucose and lipid metabolism in the liver.

Animals↗

PubMed2006

Improved search for nu(mu) --> nu(e) oscillation in a long-baseline accelerator experiment.

We performed an improved search for nu(mu) --> nu(e) oscillation with the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment, using the full data sample of 9.2 x 10(19) protons on target. No evidence for a nu(e) appearance signal was found, and we set bounds on the nu(mu) --> nu(e) oscillation parameters. At Deltam(2)=2.8 x 10(-3) eV(2), the best-fit value of the K2Knu(mu) disappearance analysis, we set an upper limit of sin(2)2theta(mue) < 0.13 at a 90% confidence level.

Journal Article↗

PubMed2006

Development of PCR-based allele-specific and InDel marker sets for nine rice blast resistance genes.

Blast resistance is one of the most important traits in rice breeding, and application of molecular markers for blast resistance breeding is likely to allow the rapid screening for the trait during early growth stages, without the need for inoculation of pathogen and phenotyping. Allele-specific PCR markers and insertion/deletion (InDel) markers, which genotype single-nucleotide polymorphisms and InDel polymorphisms, respectively, are useful tools for marker-assisted selections. We developed sets of allele-specific PCR and InDel markers for nine rice blast resistance genes -- Piz, Piz-t, Pit, Pik, Pik-m, Pik-p, Pita, Pita-2, and Pib -- which are commonly used in Japanese blast resistance rice breeding programs. For each resistance gene, we used the segregation information from thousands of progeny in several crosses or published gene locations to generate a marker that cosegregated with the gene and markers that closely flanked the gene on either side. The developed cosegregating markers uniquely discriminated among each of the lines with the individual resistance genes (except for Pita and Pita-2). Therefore, these markers will likely facilitate the development of multiline cultivars carrying one or a combination of these nine blast resistance genes. In addition, the systems we developed may be valuable tools in the quality control of seed production from blast-resistant multiline cultivars.

Alleles↗

PubMed2006

Visual function in patients with yellow tinted intraocular lenses compared with vision in patients with non-tinted intraocular lenses.

AIM: To compare the visual function in patients with short wavelength blue light blocking yellow tinted intraocular lenses (IOLs) with that in patients with non-tinted IOLs. METHODS: 74 patients scheduled for bilateral cataract surgery underwent implantation of either yellow IOLs (HOYA YA60BB) or non-tinted IOLs (VA60BB) in both eyes. Contrast visual acuity with and without a glare source was measured under photopic (100 cd/m2) and mesopic (slightly higher luminance than typically used-5 cd/m2) conditions at 2 weeks and 3 months after surgery using the contrast sensitivity accurate tester. Visual acuity and the incidence of patients who noted cyanopsia were also examined. RESULTS: No significant differences between the yellow tinted and non-tinted IOL groups were observed in mean visual acuity or in photopic or higher luminance mesopic contrast visual acuity with and without glare source at either 2 weeks or 3 months after surgery. Furthermore, there was no significant difference in contrast visual acuity loss as a result of glare. The incidence of patients who noticed cyanopsia was significantly less in the yellow tinted IOL group than in the non-tinted IOL group at 2 weeks after surgery (p = 0.0234), but no patients reported cyanopsia at 3 months. CONCLUSION: Visual function in patients with yellow tinted IOLs is virtually the same as that in patients with non-tinted IOLs.

Aged↗

PubMed2006

Difference of HBV genotype distribution between acute hepatitis and chronic hepatitis in Japan.

BACKGROUND: Recently genotype A which is rare in the patients in chronic hepatitis B (CHB) was frequently noted in patients with acute hepatitis B (AHB). To investigate their clinical and virological features, we studied the AHB patients in the past 5 years. PATIENTS AND METHODS: 98 patients with AHB and 80 patients with CHB admitted to our hospital between 1998 and 2003 were studied. RESULTS: Genotype A was not found in CHB but was frequently noted in AHB (p < 0.001). Comparison of the clinical features of acute hepatitis between the two major genotypes, A and C, homosexual and heterosexual with multiple partners were frequently seen among genotype A patients (p < 0.001). On the other hand, infection from steady partner showed a tendency to be more frequent in genotype C (p = 0.065). In genotype A, the levels of HBVDNA on admission was higher (p = 0.007) and AHB has significantly more frequently progress to chronic infection than in genotype C (p = 0.028). Phylogenetic analysis of genotype A revealed that almost all strains from homosexual men belonged not to the African type A1 but to the Western type A2. CONCLUSION: Genotype A has increased recently among AHB in Japan. This fact may correlate to promiscuous intercourse in high risk group. Prophylactic efforts should be considered to prevent the prevailing of genotype A.

Acute Disease↗

PubMed2006

Comparison of amplitude of apparent accommodation in pseudophakic eyes with that of normal accommodation in phakic eyes in various age groups.

PURPOSE: To compare the amplitude of apparent accommodation in eyes with monofocal intraocular lenses with that of normal accommodation in the phakic fellow eyes in various age groups. PATIENTS AND METHODS: In all, 130 eyes of 130 patients scheduled to undergo cataract surgery, and 130 fellow eyes that had little cataract and good visual acuity of 20/33 or better were studied. The following groups were studied: in their 40s and younger (n = 20) or in their 50s (n = 30), 60s (n = 30), 70s (n = 30), and 80s (n = 20). Using an accommodometer (Kowa HS-9E), the accommodative amplitude was measured at 1 month after surgery. RESULTS: In the patients in their 40s and younger or in their 50s, the amplitude of apparent accommodation was significantly less than that of normal accommodation; no significant difference was observed in the patients in their 60s, 70s, or 80s. The incidence of patients in whom the amplitude of apparent accommodation was more than that of normal accommodation was greater in the patients in their 60s, 70s, and 80s than in the patients in their 40s and younger and in their 50s. CONCLUSION: The amplitude of apparent accommodation is virtually equivalent to that of normal accommodation in patients older than 60 years of age.

Accommodation, Ocular↗

PubMed2006

Dietary thyroid hormone improves growth and muscle protein accumulation of black-boned chickens.

1. The objective of the study was to examine the effect of dietary thyroid hormone on performance and muscle protein accumulation of black-boned chickens. 2. A total of 720 1-d-old birds was housed in 24 pens and assigned to 4 diets containing triiodothyronine (T3) at 0, 0.1, 0.3 or 0.5 mg/kg. 3. The trial was split into starter (0 to 4 weeks) and grower (5 to 8 weeks) phases. At the beginning of the grower phase, each pen was split into two; one subgroup was fed basal diet (T3-) and the other continued with T3-added diet (T3+). 4. Dietary T3 at 0.1 mg/kg improved average daily body weight gain until week 6 but retarded it thereafter. However, T3 at 0.5 mg/kg depressed growth throughout the whole period. During weeks 7 to 8, T3 retarded growth, whereas growth recovered when T3 was withdrawn from the diet. 5. Birds fed the diet containing 0.1 mg/kg during weeks 0 to 4 and those receiving basal diet during weeks 5 to 8 showed the greatest thigh muscle growth, but this growth was depressed when they were fed the 0.5 mg/kg diet during weeks 0 to 8. 6. Serum T3 concentration was increased, while thyroxine (T4) concentration was decreased by dietary T3 treatment at 2 weeks old. At 4 weeks old, T3 and T4 concentrations decreased. At 6 and 8 weeks old, among T3-treated groups the serum T3 concentration of the T3- group was higher than that of the T3+ group. 7. In conclusion, dietary T3 improved weight gain and muscle growth of black-boned chickens before week 6, whereas supplementation depressed growth after 6 weeks. Optimum dietary T3 concentrations showed a carry-over effect on both body weight gain and thigh muscle growth.

Animal Feed↗

PubMed2006

O-(2-[18F]fluoroethyl)-L-tyrosine (18F-FET) uptake in mouse thymoma cells, and its biodistribution in mice and human volunteers.

PURPOSE: To evaluate O-(2-[18F]fluoroethyl)-l-tyrosine (18F-FET) uptake in mouse malignant thymoma (EL4), and its biodistribution in mice and humans. MATERIAL AND METHODS: First, 18F-FET uptake in EL4 cells was examined in an in vitro study. Second, the kinetics of 18F-FET uptake and its biodistribution were examined in mice after subcutaneous injection of EL4 cells and complete Freund's adjuvant. Finally, the kinetics of 18F-FET uptake and its biodistribution in healthy human volunteers were examined. RESULTS: In an in vitro study, 18F-FET was extensively incorporated in EL4 cells. In an animal study, 18F-FET accumulation in normal organs peaked within 30 min postinjection. The mean ratios of 18F-FET uptake in tumors and in inflammatory lesions to that in muscle tissue at 60 min postadministration were 2.18 (range 2.00-2.29) and 1.04 (range 0.95-1.14), respectively. In a human study, static images were taken 60 min after 18F-FET administration. Mean standardized uptake values (SUVs) of the liver (1.52, range 1.38-1.71) and kidneys (1.90, range 1.74-2.24) were nearly equal or slightly higher than that of muscle tissue (1.19, range 0.99-1.33). CONCLUSION: This study demonstrates that 18F-FET accumulation in thymoma is significantly higher than in normal organs. 18F-FET could be a useful tracer for tumor imaging.

Adult↗

PubMed2006

Fluctuations in carotid arterial distensibility during the menstrual cycle do not influence cardiovagal baroreflex sensitivity.

AIM: Fluctuations in autonomic nervous functions throughout the menstrual cycle and the underlying mechanism concerning them are not well known. This study was designed to test the hypothesis that fluctuations in cardiovagal baroreflex sensitivity (BRS) throughout the menstrual cycles of young women are due to fluctuations in carotid arterial distensibility. METHODS: In eight eumenorrhoeic healthy young women (18-24 years), we determined the variations in the carotid arterial distensibility coefficient (DC; via simultaneous ultrasonography and applanation tonometry), cardiovagal BRS (phase IV of the Valsalva manoeuvre and the sequence method; up- or down-sequence spontaneous BRS), and serum oestradiol and progesterone concentrations at five points in the menstrual cycle (menstrual = M, follicular = F, ovulatory = O, early luteal = EL, and late luteal = LL). RESULTS: Serum oestradiol and progesterone levels were consistent with the predicted cycle phases. Carotid arterial DC fluctuated cyclically, increasing significantly from the M (52.4 +/- 4.9 x 10(-3) kPa(-1), mean +/- SE) and F (52.7 +/- 4.4) phases to the O (57.6 +/- 4.4) phase and declining sharply in the EL (46.0 +/- 4.0) and LL (45.1 +/- 3.0) phases (F = 6.37, P < 0.05). Contrary to our prediction, however, cardiovagal BRS by the Valsalva manoeuvre (P = 0.73) or sequence method (up-sequence spontaneous BRS; P = 0.84: down-sequence spontaneous BRS; P = 0.67) did not change significantly during the menstrual cycle. CONCLUSION: The results suggest that, although carotid arterial distensibility fluctuates with the changes in ovarian hormone levels that occur during the menstrual cycle, the fluctuations in carotid arterial distensibility do not influence cardiovagal BRS.

Adolescent↗

PubMed2006

Reactive lymphoid hyperplasia of the liver in a patient with multiple carcinomas: a case report and brief review.

A rare case of reactive lymphoid hyperplasia (RLH) of the liver in a 75-year-old woman admitted to hospital for surgical treatment of gastric, caecal and colon carcinomas is described here. Two nodular lesions in the left and right lobes of the liver were clinically diagnosed as metastatic tumours by computed tomography of the abdomen. A demarcating grey-white mass of size 1.4 cm was observed in a partially resected liver specimen. On examining the lesion microscopically, it was found to be composed of hyperplastic lymphoid follicles, lymphocytes, plasma cells, other inflammatory cells and interlaced hyalinised fibrous tissues. In the portal tracts around the lesion, chronic inflammatory cell infiltrates were seen, but no interface hepatitis or lymphoid follicle was observed. No evidence of monoclonality was observed by immunohistochemistry for B and T cell markers, in situ hybridisation for kappa and lambda light chains, and polymerase chain reaction analysis of immunoglobulin heavy chains or T cell receptor beta and gamma gene rearrangements. Bcl-2 immunoreactivity was not observed in the germinal centre. Epstein-Barr virus (EBV) antigen (latent membrane protein-1) and EBV-encoded small RNAs were not detected. A proliferation neither of myofibroblasts nor of cells positive for follicular dendritic cell markers was observed. RLH, formerly known as pseudolymphoma, has been reported of the liver in only 14 cases and is considered to be a differential diagnosis of small nodular lesions of the liver. That RLH has an inflammatory reactive nature, not a neoplastic disposition, and that EBV does not participate in the pathogenesis of RLH is supported by this case.

Adenocarcinoma↗

PubMed2006

Estrogen-receptor-alpha-positive extramammary Paget's disease treated with hormonal therapy.

The patient was an 80-year-old man with scrotal and penile extramammary Paget's disease and prostate cancer. Both diseases were in advanced stages. Tumor cells of extramammary Paget's disease strongly expressed estrogen receptor alpha. The patient was concurrently treated with two kinds of hormonal therapy: the anti-estrogen tamoxifen (20 mg/day orally) for extramammary Paget's disease and the anti-androgen bicalutamide (80 mg/day orally) for prostate cancer. The toxicity of the therapy was mild. All of the metastatic lesions remained stable for 2 months after initiation of dual hormonal therapy. During a follow-up period of 22 months, performance status was well maintained for 17 months. Hormonal therapy may be an alternative for selected cases of advanced extramammary Paget's disease.

Aged, 80 and over↗

PubMed2006

Low tibial osteotomy for varus-type osteoarthritis of the ankle.

In this retrospective study we have assessed the results of low tibial valgus osteotomy for varus-type osteoarthritis of the ankle and its indications. We performed an opening wedge osteotomy in 25 women (26 ankles). The mean follow-up was for eight years and three months (2 years 3 months to 17 years 11 months). Of the 26 ankles, 19 showed excellent or good clinical results. Their mean scores for pain, walking, and activities of daily living were significantly improved but there was no change in the range of movement. In the ankles which were classified radiologically as stage 2 according to our own grading system, with narrowing of the medial joint space, and in 11 as stage 3a, with obliteration of the joint space at the medial malleolus only, the joint space recovered. In contrast, such recovery was seen in only two of 12 ankles classified as stage 3b, with obliteration of the joint space advancing to the upper surface of the dome of the talus. Low tibial osteotomy is indicated for varus-type osteoarthritis of stage 2 or stage 3a.

Activities of Daily Living↗

PubMed2006

Changes of pituitary, adrenal and gonadal hormones during competition among female soccer players.

AIM: This study was intended to investigate various hormones during competition among female athletes. METHODS: Subjects were elite female soccer players (n=9). Blood samples and profiles of mood states (POMS) were obtained before (Pre), during 3 days of competition (Competition), and after competition (Post-3 days). Serum concentrations were determined for dehydroepiandrosterone sulfate (DHEAS), cortisol (C), prolactin (PRL), testosterone (T), adrenocorticotropic hormone (ACTH), luteinising hormone (LH), and follicle stimulating hormone (FSH). RESULTS: Levels of C and PRL increased significantly during competition (2nd: P<0.05; 3rd: P<0.01) compared with Pre. Levels of LH increased significantly during competition (3rd day) compared with Pre (P<0.05). Levels of DHEAS changed significantly during competition, whereas levels of T, ACTH, and FSH were unchanged during competition. The fatigue score of POMS increased significantly during competition (2nd day) compared with Pre (P<0.05). CONCLUSIONS: We demonstrated that competitive stress affected hormonal status in female athletes. These findings suggest that hormonal changes reflect physical and mental stress during competition.

Adrenal Cortex Hormones↗

PubMed2005

Search for coherent charged pion production in neutrino-carbon interactions.

We report the result from a search for charged-current coherent pion production induced by muon neutrinos with a mean energy of 1.3 GeV. The data are collected with a fully active scintillator detector in the K2K long-baseline neutrino oscillation experiment. No evidence for coherent pion production is observed, and an upper limit of is set on the cross section ratio of coherent pion production to the total charged-current interaction at 90% confidence level. This is the first experimental limit for coherent charged pion production in the energy region of a few GeV.

Journal Article↗