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Biomedical subjects

M Hayashi

Publications and source records attributed to M Hayashi.

At least 199 records · Page 11Linked to original sources
PubMed2001

Changes of cone electroretinograms to colour flash stimuli after successful retinal detachment surgery.

AIM: To examine the changes in the short wavelength (S) and mixed long (L) and middle (M) wavelength sensitive cone (L,M-cone) electroretinograms (ERGs) after successful retinal detachment surgery. METHODS: Cone ERGs elicited by different colour flashes were recorded from 19 eyes with unilateral rhegmatogenous retinal detachment treated successfully by conventional buckling surgery. Ganzfeld colour flashes on a bright white background were used to elicit S-cone and L,M-cone ERGs. The ratio (operated eye/fellow eye) of the S-cone b-wave elicited by a 450 nm stimulus and the ratio (operated eye/fellow eye) of the L,M-cone b-wave elicited by a 633 nm stimulus were evaluated preoperatively and 1, 3, and 6 months after surgery. RESULTS: Preoperatively, no significant difference was observed between the ratio of the S-cone ERG amplitudes and the ratio of the L,M-cone ERG amplitudes. Postoperatively, the ratio of the L,M-cone ERGs increased significantly over the preoperative value (p=0.001) but the ratio of the S-cone ERG did not improve. There were significant differences between the ratios of the S-cone and the L,M-cone ERGs at 1, 3, and 6 months after surgery. The postoperative recovery of the S-cone ERG was significantly greater in eyes treated within 4 weeks after the onset of the detachment than in eyes treated later than 4 weeks. CONCLUSIONS: These results indicate that the impairment of the L,M-cone system caused by retinal detachment may be reversible. However, the S-cone system may have more profound permanent damage.

Adolescent↗
PubMed2001

Twenty-four-hour blood pressure changes in the course of lacunar disease.

BACKGROUND: Changes in blood pressure (BP) over time have not been considered in investigations on the relationship between BP and cerebrovascular disease (CVD). OBJECTIVE: To investigate BP changes throughout a 24-hour period in lacunar infarct patients with different outcomes. METHODS: Twelve control subjects (group 1) and 56 patients with symptomatic lacunar infarcts were studied. The infarct patients were divided into three groups: group 2, 25 patients with a fair outcome without any cerebrovascular attack or progressive dementia (mean follow-up period: 4.4 years); group 3, 14 patients with worsening of clinical dementia rating and silent lesions, which included lacunae and diffuse white matter lesions (4.5 years), and group 4, 17 patients who developed symptomatic infarcts (1.7 years). MRIs and ambulatory BP monitoring were performed for each patient on two separate occasions. No patient was treated with antihypertensive agents during the course of the study. RESULTS: In group 2, the second measurements were significantly higher than the first for 24-hour systolic BP (SBP), daytime SBP, 24-hour diastolic BP (DBP), daytime DBP (p < 0.01, for all) and nighttime DBP (p < 0.05). In group 3, the second measurements were significantly lower than the first for 24-hour SBP, daytime SBP, 24-hour DBP, and daytime DBP (p < 0.01, for all). In group 4, the second measurements were significantly lower than the first for 24-hour SBP and daytime SBP (p < 0.01). The correlation between BP and pulse rate became positive for group 2 in second measurements, but was not positive for groups 3 and 4. CONCLUSIONS: BP tended to elevate over time in patients with a fair outcome. In contrast, BP tended to decrease in those who developed dementia and symptomatic infarct. Autonomic functions including sympathetic activity might play a role in changes in BP in lacunar infarct patients during the course of disease.

Aged↗
PubMed2001

Usual interstitial pneumonia: idiopathic pulmonary fibrosis versus collagen vascular diseases.

BACKGROUND: Bronchoalveolar lavage fluid (BALF) lymphocytosis was found in patients with usual interstitial pneumonia (UIP) associated with collagen vascular diseases (CVD) other than diffuse systemic sclerosis (SSc), but it was not found in patients with idiopathic pulmonary fibrosis (IPF), a disease histologically diagnosed as UIP. This difference could be partly due to variations of UIP spectrums between IPF and interstitial pneumonia associated with CVD. METHODS: We scored histopathological findings of lung specimens obtained from 31 cases (16 IPF, 9 CVD other than SSc and 6 SSc) using a semiquantitative scoring method. All cases were diagnosed as UIP by surgical lung biopsy. None of the patients were current smokers. RESULTS: Compared with IPF and SSc cases, CVD patients without SSc presented decreased scores of fibrosis (p < 0.01) and alveolar space cellularity (severity, p < 0.05). Lymphocytes were mainly localized in the alveolar walls and the majority of cells in the alveolar spaces were macrophages. On the other hand, other scores such as cellularity and alveolar wall cell infiltrate did not vary among these three groups. CONCLUSION: Fewer macrophages in the alveolar spaces and a decrease in the degree of fibrosis may contribute to BALF lymphocytosis more in patients with UIP/CVD non-SSc than in patients with IPF/UIP and UIP-SSc.

Adult↗
PubMed2001

Plasma levels of soluble Fas during normal pregnancy.

The Fas/Fas ligand system could reportedly help to identify a mechanism for maternal immunotolerance of the fetus in human pregnancy. However, there are few reports on soluble Fas (sFas) which is an inhibitor of apoptosis during normal pregnancy. Therefore, ascertaining plasma sFas levels during pregnancy would be of interest. The subjects studied were 10 nonpregnant healthy women and 20 healthy pregnant women in the first and third trimester with singleton gestations. The plasma sFas was measured by sandwich enzyme-linked immunosorbent assay. The mean concentration of sFas was significantly decreased in normal pregnant women in the first trimester compared to age-matched control subjects, and it did not differ significantly between normal pregnant women in the third trimester and age-matched control subjects. From these results, we presume that the decreased plasma sFas plays an important role in maternal immunotolerance in the first trimester of pregnancy.

Adult↗
PubMed2001

CD26 and CD30 expression on the surface of lymphocyte during normal pregnancy.

It is increasingly apparent that the Th1/Th2 cell ratio is decreased during pregnancy. In a previous study, we revealed that combined analysis of soluble CD26 and CD30 might be a potent surrogate tool for evaluating the Th1/Th2 balance during pregnancy. Therefore, in the present study, we elucidated whether the CD26 and CD30 expression on the surface of lymphocyte is useful marker for Th1 and Th2 lymphocytes, respectively, during pregnancy with flow cytometric technique. The peripheral blood samples were obtained from 6 non-pregnant healthy women, 8 healthy pregnant women in the first trimester and 12 pregnant women in the third trimester. The mean percentages of CD26 expression did not differ significantly among these groups (p = 0.45). Also, the mean percentages of CD30 expression did not differ significantly among these groups (p = 0.32). From the present study, the expression of CD26 and CD30 did not appear to be a useful marker for Th1 and Th2 lymphocytes during pregnancy.

Adult↗
PubMed2001

Superoxide inhibits neuronal nitric oxide synthase influences on afferent arterioles in spontaneously hypertensive rats.

This study was designed to determine the influence of increased superoxide anion in neuronal nitric oxide synthase (nNOS)-dependent regulation of afferent arterioles in spontaneously hypertensive rats (SHR). Afferent arteriolar diameters of male Wistar-Kyoto rats (WKY) and SHR were assessed in vitro with the blood-perfused juxtamedullary nephron technique and averaged 21.6+/-1.6 (n=6) and 18.8+/-1.2 (n=7) micrometer, respectively. The superoxide dismutase mimetic Tempol (1, 10, and 100 micromol/L) did not influence afferent arterioles of WKY but significantly increased afferent arteriolar diameters of SHR by 20.6+/-5.5%, 25.2+/-5.4%, and 23.3+/-4.9%, respectively. In WKY (n=6), the nNOS inhibitor S-methyl-L-thiocitrulline (L-SMTC; 10 micromol/L) and the NOS inhibitor N(omega)-nitro-L-arginine (L-NNA; 100 micromol/L) significantly decreased afferent arteriolar diameters (19.6+/-1.6 micrometer) by 11.9+/-3.1% and 21.0+/-3.9%, respectively. In SHR (n=7), L-SMTC did not influence afferent arteriolar diameters (21.0+/-1.5 micrometer), but L-NNA exerted an afferent arteriolar constriction (14.8+/-3.2%) that was similar to the response observed in WKY. Experiments were also performed in the presence of 100 micromol/L Tempol. In afferent arterioles of WKY (n=6), Tempol treatment did not modulate the basal diameters (21.5+/-1.2 micrometer) or the constrictor response to L-SMTC (10.6+/-2.1%) or L-NNA (19.3+/-3.3%). In SHR (n=8), Tempol significantly increased afferent arteriolar diameters by 22.5+/-4.3% and enhanced afferent arteriolar constrictor responses to L-SMTC (18.4+/-2.7%) and L-NNA (31.9+/-2.6%). However, the nitric oxide donor S-nitroso-N-acetylpenicillamine (10 micromol/L), which similarly increased afferent arteriolar diameters (17.2+/-2.3%, n=6), did not affect afferent arteriolar responses to L-SMTC (1.5+/-2.7%) or L-NNA (18.6+/-2.3%). These suggest that superoxide anion inhibits the control of afferent arteriolar diameters by nNOS in SHR.

Animals↗
PubMed2001

Gradient micropattern immobilization of heparin and its interaction with cells.

Heparin was immobilized on a polystyrene plate in a graded micropattern by photolithography. The micropattern was confirmed by staining with brilliant green. In the presence of basic fibroblast growth factor (bFGF), the growth of NIH3T3 cells was enhanced only in the heparin-immobilized regions. This result indicated that gradient-micropattern-immobilized heparin activated bFGF for cell growth. In addition, the growth of cells was found to be affected by the surface density of immobilized heparin. The surface density was regulated by a gap length of 2 microm-width stripes immobilized with heparin. Although a high density (a region having short gap length) of immobilized heparin suppressed the cell growth in the absence of bFGF, it enhanced cell growth in the presence of bFGF. The dependence of cell function on the density of immobilized heparin was visualized by gradient-micropattern-immobilization.

3T3 Cells↗
PubMed2001

Age- and gender-related changes in ligament components.

The age- and gender-related changes in extracellular matrix components (elastin, elastin cross-links, fibrillin, collagen and glycoprotein) and mineral components (calcium, Ca; phosphorus, P) in human lumbar yellow ligaments were investigated using samples obtained from surgical specimens. The mineral (Ca and P) contents increased with ageing (r = 0.703 and r = 0.772, respectively), whereas the contents of matrix components tended to decrease with ageing (elastin r = -0.261, elastin cross-links r = -0.213, fibrillin r = 0.494; collagen r = -0.322 and glycoprotein r = -0.143). Comparison of the male and female groups revealed that the ligament elastin content and elastin cross-links decreased in the male group, whereas the ligament collagen content decreased in the female group significantly in an age-dependent manner (r = -0.788, r = -0.753 and r = -0.721, respectively). These findings demonstrate age- and gender-related changes in mineral and matrix components (especially elastin and collagen) in the lumbar yellow ligaments in the Japanese population. It is suggested that elastin and collagen metabolism in ligaments changes both with age and according to gender.

Adult↗
PubMed2001

Dietary phosphorus deprivation induces 25-hydroxyvitamin D(3) 1alpha-hydroxylase gene expression.

Dietary phosphorus deprivation causes hypophosphatemia and an increase in serum 1alpha,25-dihydroxyvitamin D(3) [1,25-(OH)(2)D(3)] concentrations. To determine the molecular mechanisms of this regulation, the effects of dietary phosphorus deprivation and hypophysectomy on 25-hydroxyvitamin D(3) 1alpha-hydroxylase (1alpha-hydroxylase) protein and messenger RNA (mRNA) expression were examined in rats. A low phosphorus diet (LPD) for 4 days resulted in hypophosphatemia and an increase in serum 1,25-(OH)(2)D(3) levels. This increase was caused by the induction of 1alpha-hydroxylase protein and mRNA expression (4- and 10-fold increases, respectively). Administration of the LPD or normal phosphorus diet to hypophysectomized (HPX) rats resulted in hypophosphatemia and suppression of 1alpha-hydroxylase gene expression, indicating that hypophosphatemia itself is not sufficient to induce 1alpha-hydroxylase mRNA expression. Administration of GH to HPX rats fed LPD could partially restore 1alpha-hydroxylase mRNA expression, whereas supplementation with insulin-like growth factor I, T(3), estrogen, or corticosterone had no effect. We also examined Phex gene expression in the bone, because the clinical features of X-linked hypophosphatemia resemble those of HPX rats. Phex mRNA expression, however, was not altered in HPX rats. In conclusion, we demonstrated that the increase in serum 1,25-(OH)(2)D(3) levels caused by dietary phosphorus deprivation is due to the induction of 1alpha-hydroxylase mRNA expression, and this increase is mediated in part by a GH-dependent mechanism.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed2001

Association between serum leptin concentrations and bone mineral density, and biochemical markers of bone turnover in adult men.

Leptin, the product of the ob gene, has been shown to inhibit bone formation in mice. We addressed whether leptin has any role in the regulation of bone mineral density (BMD) in humans. Subjects were 221 adult men with a mean (+/-SD) age and body mass index of 52.1 +/- 8.7 yr and 23.6 +/- 2.8 kg/m2. Serum leptin, carboxyterminal propeptide of type 1 procollagen (PICP; a marker of bone formation), and cross-linked carboxyterminal teleopeptide of type 1 collagen (a marker of bone resorption) were measured by RIA. BMD was assessed by single photon absorptiometry, and total fat mass was determined by bioimpedance analysis. BMD was inversely associated with serum leptin concentrations and total fat mass after adjustment for body weight. PICP, but not cross-linked carboxyterminal teleopeptide of type 1 collagen, was inversely correlated with serum leptin. These results may suggest that an increase in serum leptin reduces bone formation and decreases BMD in adult men. Leptin may be a regulator of BMD in humans.

Adult↗
PubMed2001

Changes in the occurrence of mechanical alternans after long-term beta-blocker therapy in patients with chronic heart failure.

Mechanical alternans has been observed in patients with severe congestive heart failure, and the phenomenon is considered to be a terminal sign. Therapeutic strategies for chronic heart failure have significantly developed, but it is uncertain whether patients with mechanical alternans can be effectively treated or not. Seventeen consecutive patients with dilated cardiomyopathy were enrolled: 11 were treated with beta-blockers on conventional therapeutic regimens and 6 patients were not indicated for or were unable to continue beta-blockade. Mechanical alternans was detected during cardiac catheterization in the patients under physiologic tachycardia (110 beats/min) and stepwise dobutamine loading. In the initial study, mechanical alternans occurred in 70.6% of the patients: 8 of the 11 being treated with beta-blockers and 4 of the 6 without beta-blockade therapy. In the second study, none of the patients taking beta-blockers showed mechanical alternans under the same protocol; the occurrence of mechanical alternans did not change in the patients who were not being treated with beta-blockers. The left ventricular ejection fraction increased in patients whose mechanical alternans could not be induced during the follow up, but decreased in the patients in whom mechanical alternans was repeatedly inducible. It is concluded that mechanical alternans is associated with the failing myocardium and may be potentially correctable.

Adrenergic beta-Antagonists↗
PubMed2001

Biotransformation of phenanthrene and 1-methoxynaphthalene with Streptomyces lividans cells expressing a marine bacterial phenanthrene dioxygenase gene cluster.

The phdABCD gene cluster in a marine bacterium Nocardioides sp. strain KP7 codes for the multicomponent enzyme phenanthrene dioxygenase. phdA encoding an iron-sulfur protein large subunit alpha, phdB encoding its small subunit beta, phdC encoding ferredoxin, and phdD encoding ferredoxin reductase, were replaced in such a way that the termination codons of the preceding open reading frames were overlapped with the initiation codons of the following genes. This manipulated phdABCD gene cluster was positioned downstream of the thiostrepton-inducible promoter PtipA in a high-copy-number vector pIJ6021, and introduced into the gram-positive, soil-inhabiting, filamentous bacterium Streptomyces lividans. The recombinant S. lividans cells converted phenanthrene into a cis-diol form, which was determined to be cis-3,4-dihydroxy-3,4-dihydrophenanthrene by its UV spectral data as well as HPLC property, using the authentic sample for comparison. This biotransformation proceeded very efficiently; 200 microM and 2 mm of phenanthrene were almost completely converted to its cis-diol form in 6 h and 32 h, respectively. In addition, the S. lividans cells carrying the phdABCD gene cluster were found to transform 1-methoxynaphthalene to two products, which were identified to be 8-methoxy-2-naphthol in addition to 8-methoxy-1,2-dihydro-1,2-naphthalenediol by their EI-MS, 1H- and 13C-NMR spectral data.

Actinomycetales↗
PubMed2001

Uptake and accumulation of exogenous docosahexaenoic acid by Chlorella.

Tuna oil or its hydrolysate was added to a culture of Chlorella for its nutritional fortification as a feed for rotifer. Exogenous docosahexaenoic acid (DHA) in its free form was taken up by the cells of Chlorella vulgaris strain K-22 and by other strains, but tuna oil was not taken up by the cells. Accumulated DHA was found by electron microscopy in the cells in oil droplets. All strains of Chlorella used in these experiments took up exogenous DHA into the cells. It seems that the structure of the cell wall did not affect the uptake of DHA into the Chlorella cells.

Animals↗
PubMed2001

Oxygenation reactions of various tricyclic fused aromatic compounds using Escherichia coli and Streptomyces lividans transformants carrying several arene dioxygenase genes.

Bioconversion (biotransformation) experiments on arenes (aromatic compounds), including various tricyclic fused aromatic compounds such as fluorene, dibenzofuran, dibenzothiophene, carbazole, acridene, and phenanthridine, were done using the cells of Escherichia coli transformants expressing several arene dioxygenase genes. E. coli carrying the phenanthrene dioxygenase (phdABCD) genes derived from the marine bacterium Nocardioides sp. strain KP7 converted all of these tricyclic aromatic compounds, while E. coli carrying the Pseudomonas putida F1 toluene dioxygenase (todC1C2BA) genes or the P. pseudoalcaligenes KF707 biphenyl dioxygenase (bphA1A2A3A4) genes was not able to convert these substrates. Surprisingly, E. coli carrying hybrid dioxygenase (todC1::bphA2A3A4) genes with a subunit substitution between the toluene and biphenyl dioxygenases was able to convert fluorene, dibenzofuran, and dibenzothiophene. The cells of a Streptomyces lividans transformant carrying the phenanthrene dioxygenase genes were also evaluated for bioconversion of various tricyclic fused aromatic compounds. The ability of this actinomycete in their conversion was similar to that of E. coli carrying the corresponding genes. Products converted from the aromatic compounds with these recombinant bacterial cells were purified by column chromatography on silica gel, and identified by their MS and 1H and 13C NMR analyses. Several products, e.g., 4-hydroxyfluorene converted from fluorene, and cis-1,2-dihydroxy-1,2-dihydrophenanthridine, cis-9,10-dihydroxy-9,10-dihydrophenanthridine, and 10-hydroxyphenanthridine, which were converted from phenanthridine, were novel compounds.

Actinomycetales↗
PubMed2001

DNA synthesis and fragmentation in bacteroids during Astragalus sinicus root nodule development.

Histo- and cytochemical techniques were used to study the DNA replication and fragmentation patterns in bacteroids formed by Mesorhizobium huakuii subsp. rengei in nodules of Astragalus sinicus. DNA replication was detected by the incorporation of 5-bromo deoxy-uridine. Signals denoting DNA synthesis were observed in plant nuclei within the nodule meristem and in bacteroids near the meristem. The TUNEL (TdT-mediated dUTP nick-end labeling) assay was used to measure DNA fragmentation. In nutrient-depleted 1-mpi (month(s) post inoculation) nodule sections, some bacteroids were in vacuoles, and DNA fragmentation signals were observed only in such bacteroids. In contrast, 1-mpi nodule sections without nutrient depletion showed neither bacteroid localization in vacuoles nor DNA fragmentation signals. The bacteroid translocation into vacuoles upon nutrient starvation might results from autophagy of the plant. In 2-mpi nodule sections, bacteroids with DNA fragmentation signals appeared within the cytoplasm of some nodule cells in the senescence zone.

DNA Fragmentation↗
PubMed2001

No significant differences were observed in the amounts of DNA strand breaks produced by copper between male and female liver cells of long-evans cinnamon (LEC) strain rats.

The amounts of DNA single strand breaks that are oxidative damage produced by copper were examined by comet assay in the liver cells of an inbred strain of Long-Evans Cinnamon (LEC) rats that spontaneously develops fulminant hepatitis. At 4 weeks of age, copper contents in the liver of LEC rats were approximately 30-fold higher than those of WKAH rats that are control rats used in the present study. Copper accumulated in the liver of LEC rats in an age-dependent manner and no significant differences were observed between copper contents in the livers of males and females at each week of age from 4 to 15 weeks. No significant amounts of DNA strand breaks were found in the liver cells of both male and female WKAH rats from 4 to 15 weeks of age. DNA strand breaks were produced in the substantial population of LEC rat liver cells at 10 weeks of age and induced in an age-dependent manner from 10 to 15 weeks of age. The amounts of DNA strand breaks produced by copper accumulation in the liver cells of female LEC rats are not more abundant than those in the cells of male rats, although it has been reported that hepatitis in female rats is more serious than that in male rats.

Animals↗
PubMed2001

Higher sensitivity in induction of apoptosis in fibroblast cell lines derived from LEC strain rats to ultraviolet B radiation.

When lung fibroblast cell lines from LEC and WKAH rats were irradiated with ultraviolet B (UVB) and assayed for colony formation, LEC rat cells showed a higher sensitivity than did WKAH rat cells. The LEC rat cells were approximately 1.5-fold more sensitive to UVB radiation than were the WKAH rat cells in terms of D37 values, which are the doses of UVB required to reduce cell survival to 37%. When the rat cells were irradiated with UVB in the presence of 0.5 M dimethyl sulfoxide (DMSO), which efficiently scavenges free radicals such as hydroxyl radicals, no significant difference was observed between the survival curves of either LEC or WKAH rat cells irradiated with UVB in the presence of 0.5 M DMSO and those irradiated with UVB in the absence of DMSO. Therefore, formation of free radicals may not be involved in cell death induced by UVB radiation. Flow cytometry showed that the percentage of apoptotic cells in the LEC rat cell population increased with post-incubation time after UVB radiation. The proportion of apoptotic cells in the UVB-irradiated LEC rat cell population increased as the dose of UVB was increased. In contrast, no significant proportion of apoptotic cells was observed in the UVB-irradiated WKAH rat cell population. These results showed a higher sensitivity in induction of apoptosis by UVB radiation in LEC rat cells than in WKAH rat cells.

Animals↗