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Biomedical subjects

M Hayashi

Publications and source records attributed to M Hayashi.

At least 271 records · Page 15Linked to original sources
PubMed2000

Autonomic failure in ALS with a novel SOD1 gene mutation.

The authors report a patient with ALS and a novel SOD1 gene mutation who was in the totally locked-in state and developed autonomic failure followed by sudden cardiac arrest. A neuropathologic study showed widespread multisystem degeneration, including involvement of the autonomic nuclei in the medulla and spinal cord. SOD1 gene analysis detected a missense mutation of V118L in exon 4. These findings show notable phenotypic heterogeneity for SOD1-associated ALS.

Adult↗
PubMed2000

Antibody response to toxic shock syndrome toxin-1 of Staphylococcus aureus in dairy cows.

Antibody response to toxic shock syndrome toxin-1 (TSST-1) of Staphylococcus aureus in dairy cows was examined by enzyme linked immunosorbent assay (ELISA). Serum antibody to TSST-1 was not detected in 39 (76.5%) of 51 calves, which were 1-6 months of age. In contrast, TSST-1 antibody was demonstrated in 1728 (72.6%) of 2380 lactating cows housed on 36 dairy farms. The ELISA values of antibody ranged from 0.2 to 3.0 OD and presented a distribution with the peak at 1.6 OD. The mean ELISA value differed between farms, and it increased slightly along with parturient history. Somatic cell counts of milk from 174 lactating cows was compared with TSST-1 antibody and tst1,000,000 cells per ml. The mean ELISA values in milk were lower than those of sera, but they rose as somatic cells increased. The tst gene of S. aureus detected in 76.0-86.2% of the milk samples containing somatic cells > 500,000 cells per ml, a level which indicates mastitis. The data suggests that many lactating cows may be infected by TSST-1- producing S. aureus.

Animals↗
PubMed2000

Angiotensin II type 1 receptor antagonist decreases plasma levels of tumor necrosis factor alpha, interleukin-6 and soluble adhesion molecules in patients with chronic heart failure.

OBJECTIVES: To evaluate the effects of an angiotensin (Ang II) type 1 receptor antagonist on immune markers in patients with congestive heart failure (CHF). BACKGROUND: Ang II stimulates production of immune factors via the Ang II type 1 receptor in vitro, and the long-term effects of Ang II type 1 receptor antagonists on plasma markers of immune activation are unknown in patients with CHF. METHODS: Twenty-three patients with mild to moderate CHF with left ventricular dysfunction were randomly divided into two groups: treatment with Ang II type 1 receptor (candesartan cilexetil) (n = 14) or placebo (n = 9). We measured plasma levels of immune factors such as tumor necrosis factor alpha (TNFalpha), interleukin-6 (IL-6), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1). We also measured plasma levels of the neurohumoral factors such as atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) and cyclic guanosine monophosphate (cGMP), a biological marker of ANP and BNP. RESULTS: Plasma levels of TNFalpha, IL-6, sICAM-1 and sVCAM-1 were increased in the 23 CHF patients compared with normal subjects and significantly decreased after 14 weeks of candesartan cilexetil treatment, but did not change in the placebo group. Plasma levels of BNP, which is a marker of ventricular injury, significantly decreased, and the molar ratio of plasma cGMP to cardiac natriuretic peptides (ANP + BNP) was significantly increased after candesartan cilexetil treatment, but did not change in the placebo group. CONCLUSIONS: These findings suggest that 14 weeks of treatment with an Ang II type 1 receptor antagonist (candesartan cilexetil) decreased plasma levels of the immune markers such as TNFalpha, IL-6, sICAM-1 and sVCAM-1 and that it improved the biological compensatory action of endogenous cardiac natriuretic peptides in patients with mild to moderate CHF.

Angiotensin Receptor Antagonists↗
PubMed2000

Simplified purification of human basophils.

Studies of human basophils have been limited by the low number present in peripheral blood and the difficulties of purification to homogeneity with reasonable yield and functional status. Reproducible purification of human basophils to 96.5+/-0.5% with a yield of 40.8+/-5.3% was obtained by negative selection using immunomagnetic beads following initial separation by density gradient centrifugation. Isolated cells demonstrated complete viability by vital dye exclusion and spontaneous histamine release following incubation of <5%. Stimulation with anti-IgE or calcium ionophore A23187 caused histamine release and leukotriene C(4) production. Basophils demonstrated dose-dependent chemotaxis to monocyte chemotactic protein-3. This simplified methodology results in fully functional basophils in very high purity and good yield.

Antibodies, Anti-Idiotypic↗
PubMed2000

Semi-quantitative evaluation of genotoxic activity of chemical substances and evidence for a biological threshold of genotoxic activity.

In Japan, the Chemical Substances Control Law requires evaluation of the genotoxic potential of chemical substances semi-quantitatively by application of a ranking system. During the past 10 years under the law, 1049 new chemical substances were evaluated by a reverse mutation assay in bacteria (RMA) and a chromosome aberration test in cultured mammalian cells (CAT). Of them, 130 (12.4%) were positive in the RMA and 402 (38.3%) were positive in the CAT. Eighty (7.6%) were positive in both tests. Fifty (4.8%) were positive only in the RMA, 322 (30.7%) were positive only in the CAT, and 452 (43.1%) were positive in either the RMA or the CAT. Thus, the tests complement each other in detecting genotoxic substances in vitro. To explore the "threshold" concept, we compared the genotoxic responses of Salmonella typhimurium tester strains with and without DNA repair capacity. Recently constructed strains of TA1535 lacking O(6)-methylguanine DNA methyltransferase genes (ogt(ST) or ada(ST) and ogt(ST)) showed dose-related increases in the number of revertants induced by N-ethyl-N'-nitro-N-nitrosoguanidine, methyl methanesulfonate, dimethylnitrosamine, and ethylnitrosourea, while in the same dose ranges the parental strain TA1535 did not. This finding suggests that there is a threshold at which all DNA damage induced by low dose levels of genotoxic chemicals are repaired. That biological threshold seems to exist for both DNA and non-DNA targeting chemicals.

Alkylating Agents↗
PubMed2000

Trans-4-hydroxy-2-nonenal, an aldehydic lipid peroxidation product, lacks genotoxicity in lacI transgenic mice.

In order to cast light on the significance of lipid peroxidation products for carcinogenesis, the lacI mutant frequency (MF), micronucleus induction and cell proliferation were analyzed in lacI transgenic mice treated with trans-4-hydroxy-2-nonenal (HNE), a typical example. Male mice were ip injected with HNE at doses of 0, 5 or 50 mg/kg bw and 48 h thereafter, peripheral blood was collected for analyzing micronucleus induction. After 14 days, the mice were sacrificed to allow tissue sampling for examination of lacI MF and cell proliferative activity. Sixty percent of the mice given 50 mg/kg HNE died within 5 days after the treatment, but no other mortalities were observed. Histopathologically, marked pulmonary hemorrhage was found in the 50 mg/kg HNE group mice that survived until day 14. Immunohistochemically, HNE-modified proteins were detected in their alveolar macrophages. The HNE treatment did not increase lacI MF in the liver, kidney and lung and no significant increase in micronucleus induction or cell proliferation in major organs was found in either treatment. Moreover, no tumors developed in the 5 mg/kg HNE-treated mice which survived until week 78. Our results thus indicate that HNE lacks in vivo genotoxicity in lacI transgenic mice even when lethal doses are applied.

Aldehydes↗
PubMed2000

Synergistic activation of NF-kappab and inducible isoform of nitric oxide synthase induction by interferon-gamma and tumor necrosis factor-alpha in INS-1 cells.

Interferon-gamma (IFN-gamma) is known to exert deleterious effects on pancreatic beta-cells and is implicated in the development of type 1 (autoimmune) diabetes mellitus. In this study, we investigated signaling mechanisms mediating the effects of IFN-gamma in pancreatic beta-cells using a differentiated rat insulin-secreting cell line, INS-1, with special reference to the activation of transcription factors STAT (signal transducers and activators of transcription)1 and NF-kappaB. Exposure of INS-1 cells to 100 IU/ml IFN-gamma for 24 h resulted in significant inhibition of nutrient-induced insulin secretion associated with impaired metabolism. In combination with tumor necrosis factor-alpha (TNF-alpha) (50 ng/ml), IFN-gamma elicited severe cytotoxicity and induced the expression of the inducible isoform of nitric oxide synthase (iNOS) mRNA. IFN-gamma promoted tyrosine phosphorylation and DNA-binding of STAT1 through Janus kinase (JAK)1 activation without apparent phosphorylation of JAK2. TNF-alpha did not affect STAT1 activation, but stimulated DNA-binding and transcriptional activity of NF-kappaB, both of which were further increased by IFN-gamma. These effects of IFN-gamma and TNF-alpha seem physiologically relevant, because either inhibition of STAT1 by the tyrosine kinase inhibitor herbimycin A or that of NF-kappaB by sulfasalazine resulted in the reduction of iNOS mRNA expression. In conclusion, IFN-gamma activates STAT1 and potentiates TNF-alpha-induced NF-kappaB activation in INS-1 cells, thereby inducing iNOS and cell destruction.

Animals↗
PubMed2000

Pituitary-adrenocortical responses to the first dyadic encounters in male rhesus monkeys: effect of dominance relationship.

Male rhesus monkeys unfamiliar with each other were paired in a cage, and blood samples were collected before and a few hours after pair formation. Adrenocorticotrophic hormone (ACTH) and cortisol levels in each blood sample were measured. Dominant-subordinate status was ascertained through two rank tests, the food competition test and the agonistic behavior test, which were performed immediately after pair formation. As a result, the dominance relationship was determined in seven pairs formed from five animals, and the differences in ACTH and cortisol values between the dominant and subordinate animal in these pairs were compared statistically. The day after the first encounter, a second encounter was conducted in randomly selected pairs of monkeys. In the first encounters, higher levels of both ACTH and cortisol were detected in dominant animals in comparison to subordinate animals. Changing the animal's partner altered the stress responses whenever the animal's dominant-subordinate status changed. The elevated levels of ACTH and cortisol in dominant animals disappeared on the day after the first encounter. In dominant animals, the pituitary-adrenocortical stress response reacts sharply to situational demands, whereas subordinate animals have a weaker response. This acute stress response is different from a chronic stress response. When the subordinate animal cannot escape, its hypothalamic-pituitary-adrenocortical axis appears to be suppressed.

Adrenocorticotropic Hormone↗
PubMed2000

Phosphane Sulfide/Octacarbonyldicobalt-Catalyzed Pauson - Khand Reaction Under an Atmospheric Pressure of Carbon Monoxide.

Convenient access to cyclopentenones is provided by catalytic intra- and intermolecular Pauson - Khand reactions in the presence of octacarbonyldicobalt and tributylphosphane sulfide (see scheme). In contrast to other reactions of this type, they proceed under mild conditions (70 degrees C, 1 atm CO), and commercially available [Co(2)(CO)(8)] can be used without further purification.

Journal Article↗
PubMed2000

Requirement of wild-type p53 protein for maintenance of chromosomal integrity.

Chromosomal double-strand breaks (DSBs) occurring in mammalian cells can initiate genomic instability, and their misrepairs result in chromosomal deletion, amplification, and translocation, common findings in human tumors. The tumor-suppressor protein p53 is involved in maintaining genomic stability. In this study, we demonstrate that the deficiency of wild-type p53 protein may allow unrepaired DSBs to initiate chromosomal instability. The human lymphoblastoid cell line TK6-E6 was established by transfection with human papilloma virus 16 (HPV16) E6 cDNA into parental TK6 cells via a retroviral vector. Abrogation of p53 function by E6 resulted in an increase in the spontaneous mutation frequencies at the heterozygous thymidine kinase (TK) locus but not at the hemizygous hypoxanthine phosphoribosyl transferase (HPRT) locus. Almost all TK-deficient mutants from TK6-E6 cells exhibited loss of heterozygosity (LOH) with the hemizygous TK allele. LOH analysis with microsatellite loci spanning the long arm of chromosome 17, which harbors the TK locus, showed that LOH extended over half of 17q toward the terminal end. Cytogenetic analysis of LOH mutants by chromosome painting indicated a mosaic of chromosomal aberrations involving chromosome 17, in which partial chromosome deletions, amplifications, and multiple translocations appeared heterogeneously in a single mutant. We speculate that spontaneous DSBs trigger the breakage-fusion bridge cycle leading to such multiple chromosome aberrations. In contrast, no chromosomal alterations were observed in TK-deficient mutants from TK6-20C cells expressing wild-type p53. In wild-type p53 cells, spontaneous DSBs appear to be promptly repaired through recombination between homologous chromosomes. These results support a model in which p53 protein contributes to the maintenance of genomic integrity through recombinational repair.

Actins↗
PubMed2000

Effects of portal-systemic shunt following 90% partial hepatectomy in rats.

We studied the effects of portal-systemic shunt after massive hepatectomy. Male Wistar rats were divided into two groups: one group underwent laparotomy alone (C group) and in the other group a portal-systemic shunt was placed through laparotomy (S group). After 90% hepatectomy was performed, 3-day and 1-week survival rates and histopathology were examined, and hepatic hemodynamics during the early stage after hepatectomy were measured using dye-containing microspheres. The 3-day survival rate in the S group was significantly higher, and the 1-week survival rate was slightly higher, than those in C group. Sinusoidal dilation 7 days after hepatectomy in the S group was significantly milder than that in the C group. Fatty degeneration of hepatocytes in the S group was significantly milder than that in the C group. With respect to hepatic hemodynamics during the early stage after hepatectomy, the rate of shunt (26.3%) in the S group was significantly higher than that (9.5%) in the C group. Portal pressure, total hepatic blood flow, and total hepatic blood flow per gram of liver in the S group were significantly lower than those in the C group. These results suggest that approximately 26% shunt after 90% hepatectomy in rats increases the early survival rate and improves histological changes in surviving rats 7 days after resection.

Animals↗
PubMed2000

Quantitative study of changes in intestinal morphology and mucus gel on total parenteral nutrition in rats.

Quantification of changes in gastrointestinal morphology and mucus gel has been difficult to study. In the present study, we investigated changes in rat intestine under total parenteral nutrition (TPN) using fluoresceinated lectin staining and image analysis. Wistar rats (n = 34) were divided into two groups: one group received TPN for 2 weeks, and a control group received standard rat chow and water ad libitum for the same period. A 1-cm segment of distal ileum was removed and cut into cross sections. Sections were stained with hematoxylin and eosin, and to stain the mucus, periodic acid-Schiff (PAS), alcian blue (AB), and fluoresceinated lectin, that is, FITC-labeled Ulex europaeus agglutinin I (FITC-UEA-I), were used. Light microscope images were stored in a personal computer and analyzed using image analysis. We measured perimeter length, mucosal thickness, villus area, villus surface area index, mucus stain-positive area, mucosal area ratio, and mucosal surface area ratio. Perimeter length, mucosal thickness, villus area, and villus surface area index in the TPN group were significantly less than those in the control group (P < 0.001 for each parameter). In all mucus stainings, the stain-positive area in the TPN group was significantly less than that in the control group. However, there were no significant differences in mucosal area or mucosal surface area ratios between the two groups. The FITC-UEA-I-positive area was significantly greater than the PAS- or and AB-positive area. There were significant positive correlations between the FITC-UEA-I-positive area and both the PAS-positive and AB-positive areas. TPN for 2 weeks promoted intestinal atrophy and decreased absolute quantity of mucus gel. We successfully introduced the FITC-UEA-I staining method to evaluate changes in mucus gel.

Alcian Blue↗
PubMed2000

L-histidine but not D-histidine attenuates brain edema following cryogenic injury in rats.

Oxygen free radicals have been implicated in the genesis of traumatic brain injury and brain edema (BE). Recent studies have suggested that hydroxyl radical can initiate lipid peroxidation, thus producing lipid-free radicals that may become important sources of singlet oxygen. L-histidine, a singlet oxygen scavenger, potentially can be used to treat BE. In this study we investigated the effects of L-histidine and D-histidine on BE following cryogenic injury in rats. Male Wistar rats were anaesthetized with chloral hydrate. Vasogenic BE was produced by a cortical freezing lesion. Generation of singlet oxygen from photoactivation of rose bengal was studied by electron spin resonance (ESR). Animals were separated into four groups: sham rats (n = 5), saline-treated rats (n = 10), L-histidine treated rats (n = 6) and D-histidine treated rats (n = 7). Each agent (100 mg/kg) was administered intravenously at 30 minutes before lesion production. Animals were sacrificed at 24 hours after lesion production and the brain water content was determined by the dry-wet weight method. L-histidine had no effect on rectal and brain temperature. Election Spin Resonance studies demonstrated that L-histidine is a singlet oxygen scavenger. L-histidine but not D-histidine significantly attenuated BE following cryogenic injury (p < 0.05). In conclusion, L-histidine is useful in the treatment of traumatic BE.

Animals↗
PubMed2000

Protective effect of a novel vitamin E derivative on experimental traumatic brain edema in rats--preliminary study.

Oxygen free radicals have been proposed to be one of the major mechanisms of secondary brain damage in traumatic brain injury. Protective effect by vitamin E against oxidative damage has attracted much attention. Recent studies have demonstrated a novel vitamin E derivative, 2-(alpha-D-glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol (TMG), has excellent water-solubility and antioxidant activity. The purpose of this study was to investigate protective effects of TMG on experimental traumatic brain edema (BE). Male Wistar rats were anaesthetized with chloral hydrate. Traumatic BE was produced by a cortical freezing lesion. Animals were separated into three groups: saline-treated rats (n = 4), TMG-treated (4 mg/kg) rats (n = 7) and TMG-treated (40 mg/kg) rats (n = 8). Saline or TMG was administered intravenously before lesion production. Animals were sacrificed at 6 hours after lesion production and the brain water content was determined by the dry-wet weight method. Half-life of TMG after intravenous administration of TMG was also investigated. The half life of TMG was approximately 5 minutes. TMG (40 mg/kg) significantly attenuated BE following cryogenic brain injury (p < 0.01). In conclusion, this preliminary study has demonstrated that a novel vitamin E derivative might be promising in the treatment of traumatic BE.

Animals↗
PubMed2000

Autonomic dysfunction in Machado-Joseph disease assessed by iodine123-labeled metaiodobenzylguanidine myocardial scintigraphy.

Iodine123-labeled metaiodobenzylguanidine, a radioiodinated analogue of norepinephrine, is a tracer for evaluating sympathetic function. We used iodine123-labeled metaiodobenzylguanidine myocardial scintigraphy and sympathetic skin response to study autonomic nervous functions in 19 patients with Machado-Joseph disease (MJD) and 20 control subjects. Planar imaging of all the participants was done to evaluate myocardial scintigraphy. The ratio of average counts in the heart to average counts in the mediastinum was calculated for both early and delayed images, the latter of which reflects the cardiac neural uptake of the tracer. Single photon emission computed tomography also was done on 12 patients with MJD to examine regional tracer uptake to the heart. The mean ratio of counts in the heart to counts in the mediastinum in the delayed images was lower for the patients with MJD than for the control subjects (p <0.01). Abnormal sympathetic skin response was present in 6 patients with MJD whose mean ratio of counts in the heart to counts in the mediastinum was lower than that of patients with MJD who had normal sympathetic skin response (p <0.01). A single photon emission computed tomography study showed significantly lower accumulation of the tracer in patients with MJD than in the control subjects in the anterior lateral sectors predominantly innervated by sympathetic nerves but not in the inferior septal sectors reported to be under main innervation by parasympathetic fibers. These results show that MJD is accompanied by cardiac sympathetic dysfunction, as detected by iodine123-labeled metaiodobenzylguanidine myocardial scintigraphy, which appears to be correlated with sudomotor sympathetic dysfunction.

3-Iodobenzylguanidine↗
PubMed2000

Cerebellar degeneration in hereditary dentatorubral-pallidoluysian atrophy and Machado-Joseph disease.

We examined the mechanism of cerebellar degeneration in brains obtained at autopsy from six cases of hereditary dentatorubral-pallidoluysian atrophy (DRPLA) and six cases of Machado-Joseph disease (MJD), using terminal deoxynucleotidyltransferase-mediated in situ nick end labeling (TUNEL) and immunohistochemistry for apoptosis-related proteins, neurotrophin receptors and glutamate transporters. In three subjects with DRPLA, who developed dementia and cerebellar ataxia at over 50 years of age, the number of Purkinje cells was mildly reduced, TUNEL-positive cells were observed in the molecular layer of the cerebellar cortex, and immunoreactivities for calbindin D28K and excitatory amino acid transporter-1 (EAAT1) were altered in the molecular layer. In addition, all cases of DRPLA showed a reduction of immunoreactivity for EAAT1 in the dentate nucleus. In MJD, augmentation of Bcl-x expression by the Purkinje cells, and increases in Trk B- and GFAP-immunopositive glial cells in the granular layer were observed in half of the cases, whereas immunoreactivity for EAAT-1 was preserved both in the cerebellar cortex and dentate nucleus. One case of MJD showed TUNEL-positive granular cells in the cerebellar cortex. Age-matched control subjects did not show TUNEL-positive cells or immunohistochemical changes in the cerebellum. There were neither TUNEL-positive cells nor alteration of the in situ expression of apoptosis-related proteins in the dentate nucleus in either variant of hereditary spinocerebellar degeneration, although both exhibited grumose degeneration in the dentate nucleus. These findings indicate that latent degeneration in the cerebellar cortex may occur in DRPLA and MJD, in addition to the dentate change, which is the cardinal feature in the neuropathology of these two diseases. The lesion of Purkinje cells and their processes in the molecular layer associated with altered glutamate transport may be important in DRPLA, while the significance of the abnormalities observed in some MJD cases, which might be related to apoptotic mechanism, remains unclear.

ATP-Binding Cassette Transporters↗