Search PubMed⌕ Search

Biomedical subjects

S Ito

Publications and source records attributed to S Ito.

At least 361 records · Page 20Linked to original sources
PubMed2000

Use of angiotensin II stress pulsed tissue Doppler imaging to evaluate regional left ventricular contractility in patients with hypertrophic cardiomyopathy.

There is controversy concerning whether contract-ility in the nonhypertrophied region of the left ventricular (LV) wall is impaired or normal in patients with hypertrophic cardiomyopathy (HCM). Global LV systolic function decreases with increases in afterload in this disease. This study was performed to identify abnormalities in regional LV contractility along the long and short axes in the setting of HCM with the use of angiotensin II (AT-II) stress pulsed tissue Doppler imaging (PTDI). Angiotensin II was administered intravenously to patients with asymmetric septal hypertrophy (HCM group, n = 21) and age-matched normal volunteers (N group, n = 12). We then measured the percent LV fractional shortening (%FS) and end-systolic circumferential LV wall stress by M-mode echocardiography, LV ejection fraction (LVEF) by 2-dimensional echocardiography, and time-velocity integral (TVI) of LV outflow velocity by pulsed Doppler echocardiography. The peak first and second systolic LV wall motion velocities along the long (L-Sw(1) and L-Sw(2)) and short (S-Sw(1) and S-Sw(2)) axes were measured in the LV posterior wall and ventricular septum with the use of PTDI. The end-systolic circumferential LV wall stress at baseline was significantly lower in the HCM group. The L-Sw(1) and L-Sw(2) for the posterior wall were significantly lower in the HCM group, but the S-Sw(1) and S-Sw(2) for the posterior wall and ventricular septum were similar in the two groups. The %FS, LVEF, TVI, and systolic PTDI variables along both axes for the posterior wall decreased significantly, and end-systolic circumferential LV wall stress increased significantly at AT-II doses of 0.005 or 0.010 microg/kg per minute in the HCM group. No significant changes were found in either group in the systolic PTDI variables (except for L-Sw(1)) for the ventricular septum with AT-II infusion. Contractility along the long and short axes of the nonhypertrophied LV wall is easily impaired with increases in afterload in patients with HCM, resulting in a decrease in global LV systolic function. We found AT-II stress PTDI to be a safe and useful technique for evaluating the regional LV systolic function in this disease.

Analysis of Variance↗
PubMed2000

Elevations of group II phospholipase A2 concentrations in serum and amniotic fluid in association with preterm labor.

OBJECTIVE: The purpose of this study was to determine whether the elevation of secretory group II phospholipase A(2) concentration in the serum and amniotic fluid in preterm labor is associated with intrauterine inflammation. STUDY DESIGN: Serum and amniotic fluid were collected from women with preterm delivery (<37 weeks' gestation; n = 38) and term delivery (n = 20). Phospholipase activity was measured with a highly sensitive system that was based on reverse-phase high-performance liquid chromatographic separation of 9-anthracenylmethyl derivatives of fatty acids released by phospholipase A(2). The concentrations of immunoreactive isozymes (group I or II) of secretory phospholipase A(2) were assayed with a radioimmunoassay kit with a monoclonal antibody against human pancreatic phospholipase A(2) and splenic IIA phospholipase A(2). Localization of immunoreactive group II phospholipase A(2) in the amniotic membrane was determined by immunostaining visualized with the Vectastain ABC (Vector Laboratories, Inc, Burlingame, Calif) method. RESULTS: Enzymatic activities of phospholipase A(2) in the serum and amniotic fluid specimens obtained from patients in preterm labor with chorioamnionitis were significantly higher than those in specimens from patients in term labor. Significant elevations of phospholipase A(2) activities were observed in patients with preterm labor without histologically evident chorioamnionitis. The activity of phospholipase A(2) was clearly correlated with the concentration of the immunoreactive group II phospholipase A(2). Group II phospholipase A(2) was localized in amniotic cells obtained from patients with a pathologically determined diagnosis of chorioamnionitis. The predictive value for chorioamnionitis of the group II phospholipase A(2) concentration was relatively higher than the predictive values of the concentrations of C-reactive protein and interleukins 6 and 8. CONCLUSION: Significant elevations of group II phospholipase A(2) concentrations were detected in the serum and amniotic fluid of women with preterm labor. Group II phospholipase A(2) concentration may be a useful indicator for preterm labor, and phospholipid metabolism is certainly activated both in preterm labor and in apparent inflammatory diseases.

Amniotic Fluid↗
PubMed2000

Effect of flow competition on internal thoracic artery graft: postoperative velocimetric and angiographic study.

OBJECTIVES: To assess the effects of competitive blood flow on internal thoracic artery grafts, we investigated postoperative flow velocity characteristics and angiographic findings of the grafts with various grades of native coronary artery stenosis. METHODS: Fifty patients who had an internal thoracic artery graft to the left anterior descending artery underwent intravascular Doppler graft velocimetry during postoperative angiography. Patients were divided into 3 groups according to the grade of native coronary stenosis: group H (28 patients), 80% stenosis or greater; group M (16 patients), 60% to 79% stenosis; and group L (6 patients), 40% to 59% stenosis. Phasic flow velocity of the grafts was measured with an intravascular Doppler ultrasound-tipped guide wire during angiography. Graft flow volume was calculated from the diameter and the average peak velocity. RESULTS: Average peak velocity (group H, 27.1 +/- 8.6 cm/s; group M, 16.9 +/- 3.9 cm/s; group L, 7.2 +/- 3.7 cm/s), distal graft diameter (group H, 2.27 +/- 0.23 mm; group M, 2. 00 +/- 0.28 mm; group L, 1.07 +/- 0.27 mm), and calculated graft flow volume (group H, 33.1 +/- 12.0 mL/min; group M, 16.2 +/- 5.8 mL/min; group L, 2.3 +/- 2.0 mL/min) significantly differed among the 3 groups. Graft flow in diastole and systole also differed among the 3 groups. CONCLUSIONS: Competitive blood flow reduces internal thoracic artery graft flow and diameter according to the grade of the native coronary artery stenosis. These data suggest that grafting the internal thoracic artery to the coronary artery with stenosis of a low grade can cause graft atrophy and failure.

Aged↗
PubMed2000

Pressor responses to serotonin injected into the nucleus tractus solitarius of Sprague-Dawley rats and spontaneously hypertensive rats.

Previous studies in rats have shown that injection of nanomoles of serotonin (5-hydroxytryptamine; 5HT) into the nucleus tractus solitarius (NTS) acts on 5HT3 receptors to increase arterial pressure (AP). We investigated the effect of 5HT in Sprague-Dawley (SD) rats and in spontaneously hypertensive rats (SHR). Injection of nanomoles of 5HT into the NTS of chloralose-anesthetized SD rats increased AP. This effect was inhibited by prior injection of 5HT3 receptor antagonist ondansetron. The GABA(A) receptor antagonist bicuculline did not inhibit the effect of 5HT. Bilateral injection of 5HT or ondansetron did not affect the baroreflex sensitivity. Bilateral injection of ondansetron did not alter AP. The pressor effect of 5HT was exaggerated in SHR. These results suggest that stimulation of 5HT3 receptors in the NTS increases AP independently of activation of GABAA receptors and the baroreflex sensitivity. Furthermore, this serotonergic system is supersensitive in the NTS of SHR.

Animals↗
PubMed2000

No association of glutathione S-transferase M1 gene polymorphism with diabetic nephropathy in Japanese type 2 diabetic patients.

Oxidative stress possibly contributes to the development of diabetic nephropathy. Therefore, the levels of endogenous antioxidants may be one of determinants of the susceptibility to diabetic nephropathy. Glutathione S-transferases (GSTs) can work as one of endogenous antioxidants to protect cells from oxidative stress. The M1 member of GST mu class (GSTM1) is polymorphic and only expressed in 55-60% of Caucasians because of the homozygous deletion of the gene (null genotype). Recent studies have provided evidence that the GSTM1 null genotype, i.e. lack of the GSTM1 activity, is associated with an increased susceptibility to lung cancer and colorectal cancer. The present study was conducted to determine whether the genetic polymorphism influences the development of diabetic nephropathy. We examined 105 patients with diabetic nephropathy and 69 patients without diabetic nephropathy in Japanese type 2 diabetic patients with proliferative diabetic retinopathy. GSTM1 genotyping was performed by polymerase chain reaction. The two patient groups were well matched with regard to age, body mass index and HbAlc. GSTM1 null genotype was observed in 48.6% of patients with nephropathy versus 55.1% of patients without nephropathy. The frequency of GSTM1 null genotype was not significantly higher in the patient group with nephropathy than in the patient group without nephropathy. This study is the first to investigate the association of GSTM1 gene polymorphism with the development of diabetic nephropathy. The present results suggest that GSTM1 null genotype does not contribute to the development of diabetic nephropathy in Japanese type 2 diabetic patients.

Aged↗
PubMed2000

Prediction of stroke by ambulatory blood pressure monitoring versus screening blood pressure measurements in a general population: the Ohasama study.

OBJECTIVE: To investigate the association between 24 h, daytime and night-time ambulatory blood pressures and first symptomatic stroke, to compare their predictive powers for stroke with that of casual (screening) blood pressure, and to compare the predictive power for stroke between daytime and night-time blood pressures, in a general population in Ohasama, Japan. DESIGN: A prospective cohort study. SUBJECTS AND METHODS: We obtained ambulatory blood pressure on 1,464 subjects aged > or = 40 years without history of symptomatic stroke, then followed-up their stroke-free survival. There were 74 first symptomatic stroke during the follow-up period (mean = 6.4 years). The prognostic significance of blood pressure for stroke risk was examined by a Cox proportional hazards regression model adjusted for possible confounding factors. RESULTS: The non-parametric and parametric analysis indicated that 24-h, daytime and night-time ambulatory blood pressures were linearly related with stroke risk. The likelihood ratio analysis demonstrated that these ambulatory blood pressures were significantly better related to stroke risk than did screening blood pressure, and that daytime blood pressure better predicted stroke risk than did night-time blood pressure. CONCLUSIONS: The present study which prospectively investigated the relation between ambulatory blood pressure and first symptomatic stroke risk in a general population demonstrated that (i) ambulatory blood pressure values were linearly related to stroke risk; (ii) ambulatory blood pressures had the stronger predictive power for stroke risk than did screening blood pressure; and (iii) daytime blood pressure better related to stroke risk than did night-time blood pressure.

Blood Pressure↗
PubMed2000

Japanese individuals do not harbor the T594M mutation but do have the P592S mutation in the C-terminus of the beta-subunit of the epithelial sodium channel: the Ohasama study.

OBJECTIVE: To assess the implications of polymorphisms of the amiloride-sensitive epithelial sodium channel in essential hypertension in the Japanese population by determining the incidence of the T594M mutation in the , subunit of the epithelial sodium channel, and by screening the C-terminus of the epithelial sodium channel. METHODS: Single-strand confirmational polymorphism (SSCP) analysis using two sets of primers which cover the last two-thirds of the last exon coding the B epithelial sodium channel and modification of a specific enzyme restriction site (NlaIII) for the T594M mutation were performed on 803 Japanese subjects. They were randomly selected from the study participants representative of a general population of Ohasama, Japan, who measured their home blood pressure. Polymerase chain reaction (PCR) products presenting a shift in SSCP gel, as well as controls, were directly sequenced by autoanalyser to identify the mutation. RESULTS: SSCP analysis identified altered migration in five subjects. Four SSCP variants found by sequencing were heterogeneous for the P592S (CCT to TCT) mutation conserving the PY motif, although it was not significantly associated with either home or casual blood pressure values. The resting polymorphism was at codon Thr 594, leading to no change in the amino acid sequence (ACG to ACA). None of the PCR products were modified by NlaIII, indicating the absence of the T594M mutation. CONCLUSIONS: The epithelial sodium channel variants at the C-terminus are not involved in the common form of essential hypertension in Japanese.

Adult↗
PubMed2000

Enhancement of the cAMP-induced apolipoprotein-mediated cellular lipid release by calmodulin inhibitors W7 and W5 from RAW 264 mouse macrophage cell line cells.

Apolipoprotein (apo) A-I generates high-density lipoprotein (HDL) by removing cellular cholesterol and phospholipid on the interaction with cells as a main source of plasma HDL. The reaction is induced by dibutylyl cyclic (dbc) adenosine monophosphate (AMP) in RAW 264, mouse macrophage cell line cells, and we investigated its pharmacologic modulation using this cell model. Release of cellular cholesterol and choline phospholipid by apoA-I was increased 9.9 and 4.2 times, respectively, by pretreatment of the cells with 300 microM dbcAMP for 24 h. Calmodulin inhibitors, W7 (N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide) and W5 (N(6-aminohexyl)-1-naphthalenesulfonamide), increased the apoA-I-mediated lipid release by 3 times from the dbcAMP-treated cells. The optimal drug concentrations (80 and 160 microM for W7 and W5, respectively) were not parallel with those reported for in vitro calmodulin inhibition (IC50, 28 and 240 microM for W7 and W5, respectively, toward phosphodiesterase activity), and in fact 40 microM W7 showed much stronger intracellular calmodulin inhibition than did 300 microM W5 using S7AAS2, a fluorescent peptide probe. Other calmodulin inhibitors such as amitriptyline, chlorpromazine, and trifluoperazine showed no effect on the apoA-I-mediated cholesterol release. In contrast to these results, neither dbcAMP nor W7 influenced the diffusion-mediated nonspecific cholesterol efflux to lipid microemulsion. We concluded that W7 and W5 increased the interaction of apoA-I with RAW 264 cells to generate more HDL. The effect did not seem directly correlated to their cal modulin inhibition or modulation of cAMP and protein kinase C.

Animals↗
PubMed2000

Impairment of cerebrovascular reactivity to acetazolamide in patients with normal pressure hydrocephalus.

Cerebrovascular reactivity (CVR) to acetazolamide was investigated in 41 patients with normal pressure hydrocephalus (NPH). The aetiology was subarachnoid haemorrhage in 20 patients, trauma in nine, brain tumour in three and idiopathic in nine. Mean cerebral blood flow (CBF) of the whole brain was measured by performing first-pass radionuclide angiography using 99Tcm-hexamethylpropylene++ amine oxime. Cerebrovascular reactivity was measured as the percentage change from the baseline mean CBF value after the administration of 500 mg of acetazolamide. Cerebrovascular reactivity was significantly (P < 0.001) reduced in patients with the complete triad of NPH (1.4 +/- 3.1%), regardless of the aetiology, compared with normal controls (14.7 +/- 3.3%). Patients with the incomplete triad also showed significantly (P < 0.05) reduced CVR (9.6 +/- 5.4%). Patients with the complete triad had significantly (P < 0.001) lower CVR than those with the incomplete triad. Post-operative CVR in both groups (20 patients with the complete triad and 9 patients with the incomplete triad) increased significantly, from 1.5 +/- 3.5% to 10.0 +/- 5.5% (P < 0.001) and from 8.7 +/- 4.9% to 14.9 +/- 5.4% (P < 0.05), respectively. Cerebrovascular reactivity is impaired in patients with NPH regardless of the aetiology and improves after shunting.

Acetazolamide↗
PubMed2000

Circulating adhesion molecules and severity of coronary atherosclerosis.

BACKGROUND: Circulating leukocytes are recruited at atherosclerotic sites through a family of adhesion molecules. Circulating forms of adhesion molecules in peripheral blood can be quantified now. OBJECTIVE: To evaluate the relationship between circulating adhesion molecules and severity of coronary atherosclerosis. METHODS: Subjects included 81 patients undergoing diagnostic coronary angiography, 12 of whom had normal coronary arteries (control group). The remaining 69 patients with demonstrable coronary atherosclerosis were divided into two groups by use of Gensini scores, namely mild atherosclerosis (n = 36, Gensini score 1-20) and severe atherosclerosis (n = 33, Gensini score > 20). Serum levels of circulating intercellular adhesion molecule-1 (ICAM-1), vascular cellular adhesion molecule-1 (VCAM-1), and E-selectin of groups measured before angiography were compared. RESULTS: Circulating levels of ICAM-1 in members of mild and severe atherosclerosis groups were significantly higher than those in members of the control group, whereas there was no significant difference among circulating levels of VCAM-1 in members of the three groups. Circulating levels of E-selectin in members of the mild atherosclerosis group were significantly higher than those in members of the severe atherosclerosis and control groups. CONCLUSIONS: These findings suggest that E-selectin is related to the early stage, and ICAM-1 is related to the advanced stage, of coronary atherosclerosis. With progression of atherosclerosis, one-step adhesion by ICAM-1 could become more important than multistep adhesion involving E-selectin, ICAM-1, and VCAM-1. These molecules may serve as markers for severity of coronary atherosclerosis.

Adult↗
PubMed2000

Leukocyte counts and concentrations of soluble adhesion molecules as predictors of coronary atherosclerosis.

BACKGROUND: Authors of recent studies have reported that there is a relationship between level of adhesion molecules and atherosclerosis. In an animal study it was demonstrated that there is an interaction between adhesion molecules and leukocytes in atherosclerotic tissue. OBJECTIVE: To study the relationships between coronary-artery atherosclerosis and both differential blood-leukocyte count and concentrations of soluble adhesion molecules in patients with and without coronary artery disease (CAD). METHODS: Our subjects were 168 patients who underwent diagnostic coronary angiography. Forty-eight patients had normal coronary angiograms (control group), and 120 patients had significant coronary-artery stenoses (diameter stenosis > 70%) in at least one major coronary-artery branch (CAD group). Total and differential blood-leukocyte counts, and concentrations of soluble intercellular adhesion molecule-1 (sICAM-1) and vascular cell adhesion molecule-1 (sVCAM-1) were assayed prior to angiography. RESULTS: Monocyte counts for patients in the CAD group were significantly greater than those for patients in the control group (366 +/- 99 versus 258 +/- 44/microl, P < 0.0001), as were the sICAM-1 concentrations (272 +/- 52 versus 203 +/- 24 ng/ml, P < 0.0001). The mean concentrations of sVCAM-1 in members of the two groups were the same (671 +/- 138 versus 668 +/- 97 ng/ml, P=0.4). There was a higher incidence of significant coronary-artery stenosis among patients with both a high monocyte count and a high concentration of sICAM-1 (> or = mean + SD) than there was among patients with a low monocyte count and a low concentration of sICAM-1 (> or = mean - SD; 100 versus 25%, P < 0.0001). CONCLUSIONS: Higher levels both of monocyte counts and of serum concentrations of ICAM-1 may serve as markers for coronary atherosclerosis.

Biomarkers↗
PubMed2000

Azuki bean cells are hypersensitive to cadmium and do not synthesize phytochelatins.

Suspension-cultured cells of azuki bean (Vigna angularis) as well as the original root tissues were hypersensitive to Cd (<10 microM). Repeated subculturings with a sublethal level of Cd (1-10 microM) did not affect the subsequent response of cells to inhibitory levels of Cd (10-100 microM). The azuki bean cells challenged to Cd did not contain phytochelatin (PC) peptides, unlike tomato (Lycopersicon esculentum) cells that have a substantial tolerance to Cd (>100 microM). Both of the cell suspensions contained a similar level of reduced glutathione (GSH) when grown in the absence of Cd. Externally applied GSH to azuki bean cells recovered neither Cd tolerance nor PC synthesis of the cells. Furthermore, enzyme assays in vitro revealed that the protein extracts of azuki bean cells had no activity converting GSH to PCs, unlike tomato. These results suggest that azuki bean cells are lacking in the PC synthase activity per se, hence being Cd hypersensitive. We concluded that the PC synthase has an important role in Cd tolerance of suspension-cultured cells.

Aminoacyltransferases↗
PubMed2000

Crystallization and preliminary X-ray analysis of high-alkaline pectate lyase.

Pel-15, a high-alkaline pectate lyase (pectate transeliminase; E.C. 4.2.2.2) from Bacillus sp. strain KSM-P15, has been crystallized using the hanging-drop vapour-diffusion method at 277 K. Two different crystal forms were obtained and preliminary X-ray diffraction data were collected from each crystal form at 100 K. Both forms belong to the orthorhombic space group P2(1)2(1)2(1) and contain one molecule per asymmetric unit. The unit-cell parameters of form I are a = 43.2 (2), b = 60.2 (2), c = 82.2 (2) A and those of form II are a = 42.9 (1), b = 43.4 (1), c = 105.9 (3) A. Diffraction data to a resolution of 1.5 A were collected from form II crystals using a synchrotron-radiation source.

Bacillus↗
PubMed2000

Heterozygous HPS1 mutations in a case of Hermansky-Pudlak syndrome with giant melanosomes.

We report a Japanese man with Hermansky-Pudlak syndrome, having oculocutaneous albinism with a bleeding diathesis. Gene analysis of the patient's peripheral blood cells revealed that he was a compound heterozygote for HPS1 gene mutations. One of the mutations was a novel frameshift mutation at codon 321 (a G insertion) in exon 11 ( approximately 962-963insG), and the other was a 5' splice-junction mutation of IVS5 (IVS5 + 5G-->A). The content of eumelanin in the patient's hairs was significantly reduced. Histological analysis using light and electron microscopy revealed that melanocytes in the patient's epidermis contained an appreciable number of giant melanosomes. Cultured melanocytes from the patient's skin also contained giant melanosomes. Our finding of mutations in the HPS1 gene in relation to abnormalities in melanosome morphology and melanin production shed light on the role and function of the HPS1 gene product in the synthesis of melanosomes and melanin pigment.

Adult↗
PubMed2000

[Why there were few isolations of tubercle bacilli in young children with pulmonary tuberculosis?].

We retrospectively evaluated the factors influencing the isolation of tubercle bacilli in 51 children under 14 years of age with pulmonary tuberculosis who were admitted to Yokohama City University Hospital from 1975 to 1998. Young children (0-6 years of age) with pulmonary tuberculosis were significantly less positive by smear and culture than elder children (7-14 years of age) with pulmonary tuberculosis. According to the Japanese Society for Tuberculosis classification of finding on chest X-ray film for pulmonary tuberculosis, the culture-positive patients with type II (cavitary lesions) were found in all, the culture-positive patients with type III (non-cavitary lesions) in 39.3%, and the culture-positive patients with type H (hilar and mediastinal lymphadenopathys) in 35.3%. Patients with cavitary lesions (type II) were significantly more positive by smear and culture than patients with non-cavitary lesions (type III + type H). Only 15.8% of the young children with pulmonary tuberculosis had received BCG vaccine and all had non-cavitary lesions (type III and type H). But, 84.6% out of the older children had received BCG vaccine and half had cavitary lesions. Taken together, the result was that there were few isolation of tubercle bacilli in young children with pulmonary tuberculosis because they had non-cavitary tuberculosis without delayed-type hypersensitivity to tubercle bacilli.

Adolescent↗
PubMed2000

[Meningococcemia associated with C7 deficiency].

We report a 20-year-old woman who developed meningococcemia. The patient developed fever, vomiting and skin rash, then was sent to our hospital for shock. Physical and laboratory examination revealed septic shock and DIC. Her blood culture grew Neisseria meningitidis (W135). She recovered promptly with PCG, gabexate mesilate and intensive care for shock. Hemolytic activities of the patient's complement were less than 12/CH50 during the course. Screening for each component of the complements suggested that this patient had deficiency of C7. Meningococcal disease has seldom seen in Japan. Early recognition is essential so that appropriate antibiotic therapy and supportive care can be promptly started because shock and death may ensure within hours after onset of symptoms.

Adult↗