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Biomedical subjects

K Hayashi

Publications and source records attributed to K Hayashi.

At least 235 records · Page 13Linked to original sources
PubMed2001

Systolic dysfunction and blood pressure responses to supine exercise in patients with hypertrophic cardiomyopathy.

Left ventricular function and blood pressure responses were evaluated in 56 patients with non-obstructive hypertrophic cardiomyopathy (HCM) and 12 control subjects by using a radionuclide ventricular function monitor during supine ergometer exercise. Patients with HCM were divided into 2 groups: (i) group A had no decrease in ejection fraction (EF) during exercise; and (ii) group B had a decrease in EF during exercise. During exercise, the change in end-diastolic volume did not differ between the 3 groups. In contrast, the change in end-systolic volume differed between the 3 groups (p<0.0001). The change in systolic blood pressure (SBP) also differed significantly between the 3 groups. The change in SBP in group B was smaller than that in the control group and group A, and changes in the EF and changes in the SBP between rest and peak exercise showed a significant correlation (p<0.005). These results suggest that exercise-induced systolic dysfunction in patients with non-obstructive HCM may contribute to abnormal blood pressure response in those patients.

Adult↗
PubMed2001

Effects of olopatadine hydrochloride on the cutaneous vascular hyperpermeability and the scratching behavior induced by poly-L-arginine in rats.

Intradermal injections of poly-L-arginine induce cutaneous vascular hyperpermeability and scratching behavior in rats. Recently, we elucidated that the plasma extravasation involved both histamine and substance P, while the scratching behavior involved substance P, but not histamine. This study examined the effects of olopatadine hydrochloride (olopatadine), an antiallergic drug with histamine H1-antagonistic action, on the poly-L-arginine-induced responses. Olopatadine (1 mg/kg, p.o.) significantly inhibited both the plasma extravasation and the scratching behavior, suggesting that its inhibitory effects are mediated by the suppression of neuropeptidergic action as well as histaminic action. Olopatadine seems to be a novel-type drug for the treatment of dermatitis.

Animals↗
PubMed2001

Lobar atelectasis: diagnostic pitfalls on chest radiography.

This pictorial review looks at the pitfalls in the diagnosis of lobar atelectasis on chest radiographs. Lobar atelectasis with marked volume loss is hard to recognize and may be easily missed. Lobar atelectasis presenting as a mass-like opacity may be misdiagnosed as mediastinal or lung tumour. Lobar atelectasis in an unusual location may also be misdiagnosed as other entities. Familiarity with such manifestations and consideration of anatomical alterations as the signs of lobar atelectasis are important in making the correct diagnosis.

Adult↗
PubMed2001

Characterization of a thermostable family 10 endo-xylanase (XynB) from Thermotoga maritima that cleaves p-nitrophenyl-beta-D-xyloside.

Thermotoga maritima MSB8 possesses two xylanase genes, xynA and xynB. The xynB gene was isolated from the genomic DNA of T. maritima, cloned, and expressed in Escherichia coli. XynB was purified to homogeneity by heat treatment, affinity chromatography and ion-exchange column chromatography. The purified enzyme produced a single band upon SDS-PAGE corresponding to a molecular mass of 42 kDa. At 70 degrees C, the enzyme was stable between pH 5.0 and pH 11.4, and it was stable at temperatures of up to 100 degrees C from pH 7.0 to pH 8.5. At 50 degrees C, XynB displayed an optimum pH of 6.14 and at this pH the temperature for optimal enzyme activity was 90 degrees C. XynB exhibited broad substrate specificity and was highly active towards p-nitrophenyl-beta-D-xylobioside with K(m) and k(cat) values of 0.0077 mM and 5.5 s(-1), respectively, at 30 degrees C. It was also active towards p-nitrophenyl-beta-D-xyloside. The initial product of the cleavage of p-nitrophenyl-beta-D-xyloside was xylobiose, indicating that the major reaction in the cleavage was transglycosylation, not hydrolysis.

Journal Article↗
PubMed2001

Characterization of N-acetylmuramidase M-1 of Streptomyces globisporus produced by Escherichia coli BL21(DE3)pLysS.

A gene of Streptomyces globisporus encoding N-acetylmuramidase M-1 was cloned into the pET26b vector and expressed in Escherichia coli BL21(DE3)pLysS. Maximal activity for the purified enzyme was observed at 55 degrees C with an optimal pH of 5.3, and N-bromosuccinimide strongly inhibited lytic activity even at a concentration of 0.01 mM. The enzyme showed N,O-diacetylmuramidase activity.

Journal Article↗
PubMed2001

Substrate specificity of beta-primeverosidase, a key enzyme in aroma formation during oolong tea and black tea manufacturing.

We synthesized nine kinds of diglycosides and a monoglycoside of 2-phenylethanol to investigate the substrate specificity of the purified beta-primeverosidase from fresh leaves of a tea cultivar (Camellia sinensis var. sinensis cv. Yabukita) in comparison with the apparent substrate specificity of the crude enzyme extract from tea leaves. The crude enzyme extract mainly showed beta-primeverosidase activity, although monoglycosidases activity was present to some extent. The purified beta-primeverosidase showed very narrow substrate specificity with respect to the glycon moiety, and especially prominent specificity for the beta-primeverosyl (6-O-beta-D-xylopyranosyl-beta-D-glucopyranosyl) moiety. The enzymes hydrolyzed naturally occurring diglycosides such as beta-primeveroside, beta-vicianoside, beta-acuminoside, beta-gentiobioside and 6-O-alpha-L-arabinofuranosyl-beta-D-glucopyranoside, but were unable to hydrolyze synthetic unnatural diglycosides. The purified enzyme was inactive toward 2-phenylethyl beta-D-glucopyranoside. The enzyme hydrolyzed each of the diglycosides into the corresponding disaccharide and 2-phenylethanol. These results indicate the beta-primeverosidase, a diglycosidase, to be a key enzyme involved in aroma formation during the tea manufacturing process.

Carbohydrate Sequence↗
PubMed2001

Characterization of the pro-aminopeptidase from Aeromonas caviae T-64.

The pro-aminopeptidase from Aeromonas caviae T-64 (pro-apAC) had maximal activity at 60 degrees C and was more stable than mature apAC at temperature up to 65 degrees C for 1 hour. The pH stability of pro-apAC ranged from 4.0 to 8.0, which is broader than the range for the mature apAC. The kcat/Km of pro-apAC was 1.4% to 24% of that of mature apAC.

Aeromonas↗
PubMed2001

Purification and characterization of an aminopeptidase from the edible basidiomycete Grifola frondosa.

An aminopeptidase was purified 178-fold from an extract of Grifola frondosa by ammonium sulfate precipitation and a series of column chromatographies on phenyl-Toyopearl, Sephadex G-25, and Mono-Q. The molecular mass of the enzyme was estimated to be 27 kDa and 30 kDa by gel filtration and SDS-PAGE, respectively. The enzyme had an optimum pH of 8.5 and was stable between pH 6.0 and pH 10.5, and it also had a high level of heat stability. The enzyme was inactivated by EDTA and o-phenanthroline, and it was also strongly inhibited by bestatin, but no inhibitory effect of DFP was observed. The enzyme preferentially hydrolyzed peptides containing hydrophobic residues in the N-terminal position.

Agaricales↗
PubMed2001

Isolation and identification of 2-phenylethyl disaccharide glycosides and mono glycosides from rose flowers, and their potential role in scent formation.

2-Phenylethyl 6-O-alpha-L-arabinofuranosyl-beta-D-glucopyranoside (1), and its 6-O-beta-D-xylopyraranosyl-beta-D-glucopyranoside (2) were identified in the flowers of Rosa damascena Mill. harvested at the full bloom stage. 2-Phenylethyl beta-D-glucopyranoside (3) and its beta-D-galactopyranoside (4) together with 1 and 2 were also found in the flower buds harvested 44 hrs before the opening stage. Their potential role in scent formation is discussed.

Gas Chromatography-Mass Spectrometry↗
PubMed2001

A computationally efficient method for obtaining standard error estimates for the promax and related solutions.

A computationally efficient algorithm for computing the asymptotic standard errors for the promax factor solution is proposed. The algorithm covers promax rotation with or without row normalization of the pre-rotated factor matrix. It also covers situations with either even- or odd-powered promax targets. With some modifications, the algorithm applies to Procrustean rotations with fixed or random independent targets. Simulation results show that the algorithm provides reasonable approximate standard errors for the promax solution with N = 200. In a real data example, the numerical results of the standard error computation using the proposed algorithm match those of an existing method based largely on the augmented information approach. The reasons why the proposed algorithm is more efficient than the augmented information approach are discussed.

Algorithms↗
PubMed2001

Plasma adrenomedullin levels in pregnancies with appropriate for gestational age and small for gestational age infants.

AIMS: To evaluate whether maternal and fetal plasma adrenomedullin levels in pregnancies with small for gestational age (SGA) infants are different from those in pregnancies with appropriate for gestational age (AGA) infants. METHODS: Maternal and fetal circulating adrenomedullin levels were compared between 62 pregnancies with AGA (43 delivered vaginally and 19 delivered by elective cesarean section) and 28 pregnancies with SGA (20 delivered vaginally and 8 delivered by elective cesarean section) at birth. Plasma adrenomedullin levels were measured from maternal and cord venous blood samples using a radioimmunoassay. Umbilical artery blood pH was also measured. RESULTS: There were no significant differences for maternal total adrenomedullin levels, mature adrenomedullin levels, and its ratio among the groups. There were also no significant differences for fetal total adrenomedullin levels, mature adrenomedullin levels, and its ratio among the groups. In the AGA group delivered vaginally, fetal mature/total adrenomedullin ratio (mean +/- standard error, 16.6 +/- 0.7%) was significantly higher than the maternal ratio (13.8 +/- 0.6%) (p < 0.05). In the SGA group delivered vaginally, fetal mature/total adrenomedullin ratio (18.5 +/- 1.0%) was also significantly higher than the maternal ratio (14.5 +/- 0.6%) (p < 0.05). There was no significant difference in umbilical artery blood pH among the groups. CONCLUSIONS: These results suggest that maternal and fetal plasma circulating adrenomedullin levels may play a role in maternal and fetal cardiovascular adaptation during delivery in pregnancies with both AGA and SGA infants.

Adrenomedullin↗
PubMed2001

Vatanidipine hydrochloride: a new long-lasting antihypertensive agent.

Vatanidipine is a novel dihydropyridine (DHP)-type calcium channel blocker with slow-onset pharmacological actions, which are probably due to both its slow uptake into vascular tissues and resistance in its approach to the calcium channel binding site. Vatanidipine once incorporated into vascular tissues is not easily released, even by repeated washing, thus resulting in a long-lasting action of the agent. A slow-onset and long-lasting hypotensive action was observed in various experimental hypertensive models. Clinical trials using human subjects with essential hypertension indicated that vatanidipine exerts an antihypertensive effect with a slow onset and long duration. In spite of its potent hypotensive effect, the incidence of adverse effects by vatanidipine administration has been reported to be lower than that in cases of nitrendipine. In addition to its vasodilatory effects, vatanidipine efficiently suppressed noradrenaline release from sympathetic nerve endings, thus suggesting this agent exhibits a beneficial effect in the treatment of hypertensive patients, in which the reflex activation of peripheral sympathetic nerves is unfavourable to antihypertensive therapy. In a double-blind study, vatanidipine did not show reflex tachycardia, despite producing a potent and long-lasting hypotensive effect, in contrast to the administration of nitrendipine. In an animal study, vatanidipine exhibited a protective effect against cerebrovascular lesions, through a mechanism independent of its hypotensive effect. In addition, a renoprotective effect was also observed in experimental hypertensive models. In cholesterol-fed rabbits, vatanidipine exerted an anti-atherosclerotic action, which is probably attributable to the inhibitory action of the agent on low-density lipoprotein oxidation. In essential hypertensive patients, the plasma levels of cholesterol and triglyceride decreased after vatanidipine treatment, thus suggesting that this agent may have a therapeutic potential in preventing such vascular diseases as atherosclerosis. Taken together, vatanidipine appears to be a novel and useful antihypertensive agent, which can both prevent target-organ damage and reduce cardiovascular morbidity and mortality.

Animals↗
PubMed2001

Unenhanced CT findings of vascular compromise in association with intussusceptions in adults.

OBJECTIVE: The purpose of this study was to evaluate unenhanced CT findings for predicting the degree of vascular compromise in intussusception observed at surgery. MATERIALS AND METHODS: The imaging studies, clinical records, and surgical and pathologic findings in 25 patients with intussusception were reviewed retrospectively. We evaluated six CT findings based on the abnormalities of each component of intussusception. Presence or absence of these findings was compared with the degree of vascular compromise as observed on pathologic examination, such as edema, ischemia, or necrosis. RESULTS: The hypodense layer was observed in 16 of 18 intussusceptions with various degrees of vascular compromise. A fluid collection surrounded by the returning wall, which was revealed to correspond to trapped peritoneal fluid, was observed in eight of nine intussusceptions with ischemia or necrosis. A gas collection surrounded by the returning wall was observed in two of four intussusceptions with necrosis. Free peritoneal fluid coexisted with a fluid collection surrounded by the returning wall in all the intussusceptions except one. Bowel obstruction was observed in six of nine intussusceptions with ischemia or necrosis. The maximum wall thickness was not related to the degree of vascular compromise. CONCLUSION: The CT findings of a hypodense layer in the returning wall, fluid collection in the space surrounded by the returning wall, and gas collection in the space surrounded by the returning wall can be useful in predicting the degree of vascular compromise in intussusception.

Adolescent↗
PubMed2001

A high dose of vitamin E inhibits adrenal corticosterone synthesis in chickens treated with ACTH.

The present experiment was conducted to study the effects of dietary vitamin E on plasma corticosterone (CTC) concentration and adrenal steroid syntheses in chickens treated with adrenocorticotropic hormone (ACTH). Chickens were divided into ACTH(-) and ACTH(+) groups, and each group was further divided into three subgroups administered with vitamin E (500 or 5,000 mg/kg diet) and without the vitamin. Vitamin E (DL-alpha-tocopheryl acetate) was mixed with the basal diet at levels of 500 and 5,000 mg/kg and fed for 6 d. ACTH (20 IU/kg body weight) was given daily by intraperitoneal injection for 5 d. alpha-Tocopherol levels in the plasma and adrenal gland were markedly elevated by vitamin E feeding, and the level of adrenal free cholesterol (CHOL), which is used for steroid synthesis, was significantly decreased by vitamin E feeding in a dose-dependent manner. However, the level of adrenal CHOL ester was unchanged by any treatment. The elevations of pregnenolone, progesterone and CTC levels in the adrenal gland of chickens with ACTH treatment were decreased by vitamin E administration. The elevation of plasma CTC concentration in the ACTH(+) group was dramatically decreased by vitamin E administration, while that concentration was not influenced by the vitamin administration in the ACTH(-) group. These findings indicate that vitamin E suppresses the elevation of the plasma CTC concentration due to ACTH in chickens, possibly by inhibiting the conversion of CHOL ester to free CHOL in the adrenal gland.

Adrenal Glands↗
PubMed2001

Changes in intratumoral thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) mRNA expression in colorectal and gastric cancer during continuous tegafur infusion.

Thymidylate synthase (TS) is the target enzyme of 5-fluorouracil (5-FU), and dihydropyrimidine dehydrogenase (DPD) is the key enzyme in the 5-FU catabolic pathway. We wanted to determine whether the TS and DPD mRNA expression levels of gastric and colorectal cancer patients would be affected by tegafur (futrafur:FT)-based chemotherapy and whether changes in their expression might be responsible for patient outcome. Thirty-five patients with resectable advanced primary gastric cancer and 36 patients with resectable advanced primary colorectal cancer were the subjects of this study. They all underwent neoadjuvant chemotherapy with protracted infusion of FT alone or FT plus low doses of cisplatin. The TS and DPD mRNA expression levels of endoscopic biopsy specimens before chemotherapy and surgical specimens after chemotherapy were measured by TaqMan reverse transcription-PCR assay using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as the internal standard. There was a significant difference in the DPD mRNA levels during chemotherapy in the colorectal cancers. Although the TS and DPD levels were unrelated to any conventional histopathological grade factors, colorectal cancer patients whose surgical specimens contained lower TS and DPD mRNA levels had longer disease-free intervals. The results of this study suggest that FT may affect DPD mRNA expression in colorectal cancer patients, that TS/DPD expression can be regarded as an independent prognostic factor, and that colorectal cancer patients with low TS and low DPD mRNA are candidates for FT-based adjuvant chemotherapy. In addition, quantitative analysis of the change in TS/DPD mRNA in surgical specimens during FT-based chemotherapy might be a more accurate means of predicting the post-operative disease-free interval of colorectal cancer patients than analysis of endoscopic specimens before chemotherapy. There also seems to be a relation between regulation of TS and DPD during FT chemotherapy. Elucidation of the mechanisms regulating TS and DPD mRNA expression might make it possible to predict sensitivity and/or toxicity to FT.

Antineoplastic Agents↗
PubMed2001

Lipoprotein analysis using agarose gel electrophoresis and differential staining of lipids.

We established a strategy to directly measure cholesterol and triglyceride levels of each lipoprotein fraction using a combination of agarose gel electrophoresis and differential staining. The cholesterol and triglyceride levels determined by electrophoresis correlated significantly with those of ultracentrifugation. The correlation coefficients between these methods were, for cholesterol levels 0.975(very low density lipoproteins, VLDL), 0.986(low density lipoproteins, LDL) and 0.965(high density lipoproteins, HDL) and for triglyceride levels 0.994(VLDL), 0.963(LDL) and 0.959(HDL) respectively. Both intra-and inter-assays showed low values of coefficients of variation (CV) (less than 3.57%). We observed a strong linearity between staining and triglyceride concentration. An increased VLDL-cholesterol was observed in type III subjects, a result which enabled distinction between type III and type IIb or type V lipoproteinemia. The method revealed lipoprotein patterns in some samples otherwise unexpected from their corresponding serum lipid parameters. Analyses of these electrophoretic patterns thus provide an effective technique to classify types of hyperlipidemia defined by the WHO. Furthermore, quantitative measurement of chylomicrons, usually difficult, proved to be achievable, providing an additional analysis of postprandial hyperlipidemia and the exact measurement of LDL-cholesterol after diet. Consequently, we recommend this simple and easy method for clinical evaluation of abnormalities in lipoprotein profiles.

Chylomicrons↗