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S Sasaki

Publications and source records attributed to S Sasaki.

At least 127 records · Page 7Linked to original sources
PubMed2001

Group C rotavirus NSP4 induces diarrhea in neonatal mice.

Nonstructural glycoprotein NSP4 of group A rotavirus induces diarrhea in neonatal mice by functioning as an enterotoxin. Previously, our laboratory reported that the structural features of group A and group C rotavirus NSP4 proteins are well conserved despite a lack of sequence homology between group A and group C rotavirus NSP4 proteins [Horie Y, et al., Arch Virol (1997) 142: 1865-1872]. To test whether group C rotavirus NSP4 has an enterotoxigenic activity, we expressed in Escherichia coli the carboxy two-thirds (corresponding to amino acid residues 55-150) of the NSP4 protein derived from group C rotavirus strain Ehime 9301. This truncated NSP4 protein was able to induce diarrhea in 5-day-old CD-1 mice when administered intraperitoneally. Thus, group C rotavirus NSP4 acts as an enterotoxin like group A rotavirus NSP4.

Animal Population Groups↗
PubMed2001

Successful late management of spontaneous esophageal rupture using T-tube mediastinoabdominal drainage.

BACKGROUND: Spontaneous esophageal rupture is extremely rare, and early symptoms of the disease are similar to those of emergency diseases of the chest and abdomen. The diagnosis and treatments are often delayed, resulting in an unfavorable outcome in some cases. METHODS: We performed improved T-tube drainage for spontaneous esophageal rupture in 5 patients between 1995 and 1999. Our improved method was a modified procedure of the reported method of Abbott et al, as follows: a T-tube was inserted into the esophagus. A separate stab incision was made in the abdominal wall, and the long limb of the T-tube was brought out through this incision ensuring that the course of the T-tube intra-abdominally was short and straight, with some slack to allow for postoperative abdominal distension. An advantage of this method was that it facilitated healing of the fistula after removal of the T-tube. RESULTS: All patients were treated with a satisfactory outcome. CONCLUSION: This improved T-tube drainage was technically very easy and safe method for spontaneous esophageal rupture in severe cases.

Abdomen↗
PubMed2001

Proinflammatory cytokines in cerebrospinal fluid in repair of thoracoabdominal aorta.

BACKGROUND: Little is known about alterations of cytokine levels in cerebrospinal fluid (CSF) during thoracoabdominal aortic surgery. We measured perioperative CSF cytokine levels to determine their clinical significances. METHODS: Perioperative serum and CSF levels of cytokine were measured in 15 adult patients undergoing repair of the descending thoracic aorta (n = 4) or thoracoabdominal aorta (n = 11). All patients underwent prosthetic replacement and perioperative CSF drainage. Serum and CSF levels of tumor necrosis factor-alpha, Interleukin- (IL-) 1beta, IL-6, IL-8, IL-10, and IL-12 were measured before operation and at 0, 6, 12, 18, 24, 48, and 72 hours postoperatively using enzyme-linked immunosorbent assays. RESULTS: There were no hospital deaths, but 1 patient suffered paraplegia. Cerebrospinal fluid IL-8 levels peaked at immediately after operation (751.7 +/- 42.1 pg/mL versus preoperative levels, 54.9 +/- 24.6 pg/mL; p < 0.001), and the higher levels persisted for 72 hours. In contrast, serum IL-8 levels did not change and remained lower than CSF levels. The patient with paraplegia had the highest CSF IL-8 levels throughout the study period. Serum and CSF levels of tumor necrosis factor-alpha, IL-1beta, IL-6, and IL-12 did not significantly change. Serum and CSF levels of IL-10 were significantly elevated after operation compared with preoperative levels. In contrast to IL-8, serum IL-10 levels surpassed CSF levels. CONCLUSIONS: Cerebrospinal fluid IL-8 levels are significantly elevated in thoracoabdominal aortic operation, and may be the most sensitive to the inflammatory response in the ischemic spinal cord injury. Persistent elevation of CSF IL-8 levels may be predictive of further development of neurologic deficits, and a reduction of proinflammatory cytokine levels may be a beneficial effect of CSF drainage, but this requires further investigation.

Adult↗
PubMed2001

Estrogen replacement therapy in postmenopausal women augments reactive hyperemia in the forearm by reducing angiotensin converting enzyme activity.

The precise mechanism of the vasoprotective effect of estrogen replacement therapy in postmenopausal women is not fully understood. The present study sought to determine the role of nitric oxide (NO) and angiotensin-converting enzyme (ACE) in the vasodilator response of the forearm vessels induced by estrogen administration to postmenopausal women. Subjects were divided into two groups. One group received conjugated equine estrogen (0.625 mg daily) orally for 3 months (n=26), while the other received no treatment (control group, n=10). Forearm blood flow was measured by strain-gauge plethysmography. The concentrations of nitrite/nitrate (metabolites of NO), ACE activity, and lipid parameters were measured. Basal forearm blood flow, body weight, blood pressure, and heart rate were similar at baseline in both groups. After 3 months of estrogen administration, the maximal forearm blood flow response during reactive hyperemia and the serum level of nitrite/nitrate each showed a significant increase over baseline values: from 23.6+/-2.0 to 36.5+/-3.1 ml/min per 100 ml tissue (P<0.01), and from 24.8+/-2.3 to 38.6+/-3.6 micromol/l (P<0.01), respectively. Plasma levels of ACE activity were significantly reduced from baseline after 3 months of estrogen treatment (from 12.2+/-0.6 to 10.9+/-0.6 IU/l, P<0.01). No changes were seen in controls. The change in forearm blood flow after sublingual nitroglycerin was similar at baseline versus after 3 months of estrogen administration. The increase in the serum level of nitrite/nitrate after 3 months of estrogen therapy showed a significant inverse correlation (r=0.52, P<0.01) with the reduction in the plasma level of ACE activity. There was no significant correlation between the increase in serum nitrite/nitrate and any change in serum lipids, blood pressure, or other parameters. The administration of oral estrogen to postmenopausal women for 3 months increased the NO-mediated forearm endothelium-dependent vasodilatation. This was likely due, at least in part, to ACE inhibition. The latter may be one mechanism by which ERT provides its well-known cardiovascular benefit.

Blood Flow Velocity↗
PubMed2001

A field evaluation of in situ biodegradation of trichloroethylene through methane injection.

A field study of biodegradation of trichloroethylene (TCE) through methane injection was conducted at the yard of a home in Japan. Methane was selected as the safest substrate for injection into groundwater. Methane, oxygen, nitrate, and phosphate were introduced into groundwater contaminated with 220 microg/L of TCE. After a week of biostimulation, methane concentrations gradually decreased below the detection limit. Methane oxidizing bacterial numbers increased from 10 to 10(4) cells/mL with methane consumptions. During methane injection. 10-20% of TCE removal was observed. The biotransformation yield was 3-13 mgTCE/gCH4 in this field test. After methane injections were stopped, TCE removal was not observed. These results indicated that bioremediation using methane was useful as a safe technology for a TCE-contaminated area near homes.

Biodegradation, Environmental↗
PubMed2001

Comparison between ultrasonography and retrograde urethrography for detection of prostatic utricle associated with hypospadias.

OBJECTIVES: To evaluate the practical application and limitation of ultrasonography and retrograde urethrography in detecting prostatic utricle associated with hypospadias. METHODS: Between 1995 and 1999, 80 patients with hypospadias, 1 month to 16 years of age (mean age 3 years, 6 months), underwent ultrasonography and retrograde urethrography to detect the prostatic utricle. RESULTS: Of the 80 patients examined, the prostatic utricle was found in a total of 36 patients (45.0%) by ultrasonography and/or retrograde urethrography. Ultrasonography revealed the prostatic utricle in 27 (75%) of the 36 patients; in 6 of the 27, it was not detected by retrograde urethrography. Retrograde urethrography revealed the prostatic utricle in 30 (83%) of the 36 patients; in 9 of the 30, it was not visualized by ultrasonography. Retrograde urethrography was slightly more sensitive in detecting the prostatic utricle than was ultrasonography. In the remaining 44 patients, the prostatic utricle was not detected by either examination method. CONCLUSIONS: Although retrograde urethrography is considered the most useful method for detecting any degree of the prostatic utricle, we recommend routine ultrasonography because it is noninvasive, painless, and simple.

Adolescent↗
PubMed2001

Spreading depolarization waves triggered by vagal stimulation in the embryonic chick brain: optical evidence for intercellular communication in the developing central nervous system.

Throughout experiments on multiple-site voltage-sensitive dye recordings of neural activity in embryonic chick brain preparations, we have found a novel type of depolarization waves which spread widely from the brainstem to the whole brain region at a rapid rate (mm/s). This depolarization wave was triggered by glutamate-mediated postsynaptic potentials and was especially correlated to N-methyl-D-aspartate receptor function. Evidence that the spreading depolarization wave is eliminated by octanol or 18beta-glycyrrhetinic acid suggests that the depolarization wave depends on functions of gap junctions. The profile obtained with Ca(2+)-imaging experiments also suggests that the propagation of the depolarization wave is accompanied by a calcium wave. These results provide new evidence for intercellular functional communication between neural cells in the vertebrate central nervous system during embryonic development.

Animals↗
PubMed2001

Relationship between the angiotensin-converting enzyme genotype and the forearm vasodilator response to estrogen replacement therapy in postmenopausal women.

OBJECTIVES: We sought to evaluate the relationship between the angiotensin-converting enzyme (ACE) genotype and the change in forearm vasoreactivity in response to a three-month course of oral estrogen in postmenopausal women. BACKGROUND: The ACE genotype is a known predictor of the response to an ACE inhibitor drug; however, it is not clear whether it can modify the effect of estrogen replacement therapy (ERT) on endothelial function in postmenopausal women. METHODS: Fifty-five postmenopausal women received 0.625 mg of conjugated equine estrogen daily for three months. Forearm blood flow (FBF) was measured by strain-gauge plethysmography. RESULTS: Twenty-one, 25 and 9 patients had the insertion/deletion (ID), II and DD genotypes, respectively. Plasma ACE activity was significantly higher at baseline in patients with either the DD or ID genotype than in those with the II genotype (p < 0.05). A significant decrease in plasma ACE activity with ERT was seen in the ID and II genotypes (p < 0.05), but not in the DD genotype. There were no significant differences in the FBF responses to reactive hyperemia at baseline between the three groups. Estrogen replacement therapy did not alter the FBF response to reactive hyperemia in the DD genotype (4.0 +/- 1.3%), although ERT significantly increased the FBF response in the ID and II genotypes (32.6 +/- 7.5% and 30.6 +/- 6.5%, respectively; p < 0.05). Forearm blood flow after administration of sublingual nitroglycerin did not change over three months in any of the three groups. CONCLUSIONS: These findings suggest that the effect of ERT in postmenopausal women on forearm endothelial function may be determined in part by the genotype of the ACE gene.

Administration, Oral↗
PubMed2001

Sensitivity of self-reports of cancer in a population-based prospective study: JPHC Study Cohort I.

The sensitivity of self-reports of cancer may differ among cultures, and not many studies have dealt with it. The authors measured the sensitivity of 615 individuals from the JPHC Study Cohort I in Japan who responded to a questionnaire in 1995 and had had a cancer registry report since 1990. Sensitivity as calculated using registered cancer as the gold standard was 0.36 for any cancer, but varied considerably by site: 0.81, 0.42, 0.41, 0.26, 0.14 and 0.08 for breast, uterus, stomach, lung, colorectum and liver, respectively. This sensitivity by site relates positively with the cancer incidence/death ratio (an index of prognosis) of each site. A false name was reported in 71% of colorectal cancer cases (namely polyp) and in 51% of stomach cases (ulcer and/or polyp). In conclusion, the sensitivity of self-reports of cancer was much lower in this cohort than in the US results except for breast cancer.

Educational Status↗
PubMed2001

Reduction of white coat effect by cilnidipine in essential hypertension.

Stress elevates blood pressure (BP) by increased sympathetic nerve activity. Cilnidipine, a novel dihydropyridine calcium antagonist that has inhibitory actions on N-type as well as L-type voltage-dependent calcium channels, has been reported to attenuate the cold stress-induced increase in plasma norepinephrine and BP in rats. Because white coat effect is associated with an enhanced pressor response to mental stress, we postulated that cilnidipine would attenuate white coat effect in patients with essential hypertension. Sixty-one consecutive outpatients (50 men, 11 women) with essential hypertension were studied prospectively. Twenty-nine patients were treated with either cilnidipine (n = 15) or nifedipine, a representative L-type voltage-dependent calcium antagonist (n = 14). Gender, age, body mass index, duration of hypertension, target organ damage of hypertension, and BP and heart rate (HR) were not significantly different between cilnidipine and nifedipine groups, and both systolic (SBP) and diastolic BP (DBP) were significantly decreased after treatment in both groups. White coat effects on systolic and DBP and HR were not significantly different between groups before antihypertensive treatment. Cilnidipine, but not nifedipine, significantly reduced white coat effects on SBP and HR. Furthermore, white coat effects on systolic BP and HR were significantly lower after treatment in the cilnidipine group compared with the nifedipine group. These data suggest that cilnidipine may reduce white coat effect in hypertensive patients by N-type calcium channel antagonism.

Blood Pressure↗
PubMed2001

Effect of obesity on endothelium-dependent, nitric oxide-mediated vasodilation in normotensive individuals and patients with essential hypertension.

The purpose of this study was to determine the interdependent and independent effects of hypertension and obesity on endothelial function in humans. We evaluated the forearm blood flow (FBF) response to acetylcholine, an endothelium-dependent vasodilator, and isosorbide dinitrate (ISDN), an endothelium-independent vasodilator, in 16 lean and 12 obese normotensive individuals and the 18 lean and 15 obese hypertensive patients with no history of smoking, hypercholesterolemia, diabetes mellitus, or renal dysfunction. The FBF was measured using a mercury-filled Silastic strain-gauge plethysmograph. The systolic and diastolic blood pressures (BP) and forearm vascular resistance were significantly greater in hypertensive patients than in the normotensive individuals. Insulin resistance, determined by a homeostatic model assessment (HOMA), was significantly greater in the obese group than in the lean group (3.59 +/- 1.68 v 1.91 +/- 1.12, P < .01). There was no significant difference in the HOMA index between normotensive and hypertensive subjects regardless of weight. The response of FBF to acetylcholine was greatest in lean normotensive individuals and least in obese hypertensive patients (40.5 +/- 8.5 and 10.4 +/- 2.8 mL/min/100 mL of tissue, P < .001 v other groups). The FBF response was similar in obese normotensive individuals and lean hypertensive patients (24.1 +/- 7.9 and 19.3 +/- 3.2 mL/min/100 mL of tissue). The vasodilatory effect of ISDN was similar in all four groups. Multiple regression analysis revealed that the maximal FBF response to acetylcholine correlated independently with age (P = .043), obesity (P = .012), HOMA index (P = .002), and mean BP (P < .001). These findings suggest that obesity and hypertension are independently involved in abnormal endothelium-dependent vasodilation by attenuated nitric oxide production.

Acetylcholine↗
PubMed2001

Active oligonucleotides incorporating alkylating an agent as potential sequence- and base selective modifier of gene expression.

A number of cross-linking (alkylating) agents have been developed and incorporated into the oligonulceotides for sequence selective control of gene expression. Recently, potential application of such active oligonucleotides has been expanding from use for improvement of inhibition efficiency to new biotechnology that may enable chemical alteration of genetic information. These interests in active oligonucleotides have encouraged the generation of new cross-linking agents that exhibit high efficiency for application of either in vitro or in vivo. This mini review summarizes structures of alkylating agents, in particular, a new basic skeleton for cross-linking, a 2'-deoxyribose derivative of 2-amino-6-vinylpurine that has been recently developed by the author's group. The 2-amino-6-vinylpurine has been shown to form a complex with cytidine under acidic conditions, and brings the vinyl and the amino reactive groups into proximity to achieve efficient alkylation. A new strategy was designed so that the reactivity of 2-amino-6-vinylpurine can be induced from the corresponding phenylsulfoxide derivative within a duplex with the complementary strand. The validity of the new strategy has been proven by achievement of cytidine-selective cross-linking with remarkably efficiency.

Alkylating Agents↗
PubMed2001

Food composition and empirical weight methods in predicting nutrient intakes from food frequency questionnaire.

PURPOSE: Although the empirical weight (regression-based) method has theoretical advantages over the traditional food composition method in predicting nutrient levels from food frequency questionnaires (FFQs), the empirical assessments have been limited. METHODS: We compared the validity of the two approaches for a 44-item questionnaire used in a population-based prospective study in Japan. Based on four 7-day diet records and questionnaire responses collected from a subsample of the prospective study (94 men and 107 women), we developed a food composition table and stepwise regression models to predict intakes of energy and 14 nutrients from the questionnaire. RESULTS: When we applied the two methods to an independent population (207 men and 166 women) providing a 3-day diet record and responding to a 36-item dietary questionnaire, energy-adjusted and deattenuated correlation coefficients between the questionnaire and the diet records were not higher for the empirical weight method than for the food composition method; the median (range) was 0.22 (0.07-0.57) for men and 0.23 (-0.09-0.62) for women in the former method, and 0.26 (-0.04-0.58) for men and 0.38 (0.18-0.67) for women in the latter method. CONCLUSIONS: We did not find the improved validity of FFQ by empirical weight method in predicting nutrient intakes.

Cohort Studies↗
PubMed2001

Apoptosis-mediated enhancement of DNA-raised immune responses by mutant caspases.

Apoptotic bodies can be used to target delivery of DNA-expressed immunogens into professional antigen-presenting cells (APCs). Here we show that antigen-laden apoptotic bodies created by vectors co-expressing influenza virus hemagglutinin (HA) or nucleoprotein (NP) genes and mutant caspase genes markedly increased T-cell responses. Both CD8 and CD4 T-cell responses were affected. The adjuvant activity was restricted to partially inactivated caspases that allowed immunogen expression before the generation of apoptotic bodies. Active-site mutants of murine caspase 2 and an autocatalytic chimera of murine caspase 2 prodomain and human caspase 3 induced apoptosis that did not interfere with immunogen expression. The adjuvant activity also enhanced B-cell responses, but to a lesser extent than T-cell responses. The large increases in T-cell responses represent one of the strongest effects to date of a DNA adjuvant on cellular immunity.

3T3 Cells↗
PubMed2001

Highly proliferative fibroblasts forming fibrotic focus govern metastasis of invasive ductal carcinoma of the breast.

We have already reported that invasive ductal carcinomas (IDCs) with fibrotic focus (FF) have more aggressive characteristics than those without FF. FF is composed of a mixture of fibroblasts and various amounts of collagen fibers, suggesting that highly proliferative fibroblasts forming FF increase the malignant potential of IDCs with FF. The purpose of this study was to examine whether there is a difference of proliferative activity of fibroblasts forming and not forming FF, which plays an important role in the tumor progression of IDCS: Two hundred three consecutive cases of IDC of the breast surgically treated at the National Cancer Center Hospital East formed the basis for this study. The proliferative activity of the fibroblasts forming the FF was immunohistochemically evaluated by using mouse MIB-1 monoclonal antibody against Ki-67 antigen. The MIB-1 labeling index (LI) is the percentage of fibroblasts forming FF that have positively stained nuclei, and 300 fibroblasts were counted in each FF. The significance of the proliferative activity of fibroblasts forming FF with regard to lymph node metastasis (LNM) or distant-organ metastasis (DOM) was compared with well-known prognostic parameters. Multivariate analysis demonstrated that high MIB-1 LI of fibroblasts forming FF significantly increased the relative risk of LNM and the hazard rate of DOM (P < .001 and P = .009). The present study indicated that the metastatic ability of IDCs with FF is highly dependent on the proliferative activity of the fibroblasts forming FF.

Adult↗
PubMed2001

Validity and reproducibility of a self-administered questionnaire to determine dietary supplement users among Japanese.

OBJECTIVE: To evaluate reproducibility and validity of a self-administered food frequency questionnaire (FFQ) to determine the dietary supplement use. DESIGN: Questionnaire data were compared with dietary records (DR) in four 7 day periods for validity. FFQ1 and FFQ2 administered at an interval of approximately one year were compared for reproducibility. SETTING AND SUBJECTS: A total of 361 samples were selected for a validation study of a questionnaire from the subgroup of the Japan Public Health Center-based prospective Study on cancer and cardiovascular disease (JPHC Study) cohort II. Categories of dietary supplements in the FFQ were 'multivitamins', 'beta-carotene', 'vitamin C', 'vitamin E', and 'other supplements'. For each category, inquiries were made as to the brand name, frequency and duration of use. A dietary supplement user was defined as a subject who used a dietary supplement one or more times a week for a year or longer. RESULTS: Prevalence of overall supplement use was 10.9%. Percentage agreement between FFQ1 and FFQ2 was 91.7%. Sensitivity and specificity of supplement use by FFQ were 80.6% and 89.2%, respectively. Sensitivity was high for 'vitamin C'. When the self-reported categories were corrected, sensitivity for 'multivitamins' and 'vitamin E' improved. CONCLUSIONS: The FFQ on dietary supplements used for the JPHC 5 y follow-up survey was valid to determine overall use and well-defined dietary supplement use such as vitamin C. Categories must be corrected when determining multivitamin and 'vitamin E'.

Ascorbic Acid↗
PubMed2001

Single measurement of serum phospholipid fatty acid as a biomarker of specific fatty acid intake in middle-aged Japanese men.

OBJECTIVE: To assess the utility of serum phospholipid fatty acid (FA) levels as a biochemical indicator of habitual dietary fatty acid intake in Japanese, whose diet is characterized by low fat intake and high intake of n-3 polyunsaturated fatty acids (PUFA) of marine origin. SUBJECTS AND METHODS: Eighty-seven male volunteers from four public health center districts that were part of the Japan Public Health Center based Prospective Study (JPHC Study) cohort I, were included in this study. Habitual intake of fatty acid was obtained by 7 day weighed dietary records four times (in one area only twice) in 1994--1995. Blood was collected twice, in February and August of the same year, and the composition of FA in serum phospholipid was analyzed by gas chromatography. The correlation coefficient between serum phospholipid FA levels and fatty acid intake was calculated. RESULTS: High correlations were observed for eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA), which are marine origin n-3 PUFA (r=0.75, 0.49, 0.50, respectively). No significant correlation was observed for saturated fatty acid (SFA), although the monounsaturated fatty acid (MUFA), palmitoleic acid and oleic acid intake were moderately correlated (r=0.22, 0.35, respectively). The correlations for EPA, DPA and DHA were similar in both samples collected in February and August. CONCLUSIONS: These data suggest that in populations with a high and stable over time intake of n-3 PUFA of marine origin, a single measurement of serum phospholipids reflects the ranking of habitual intake of marine origin n-3 PUFA.

Biomarkers↗