Biomedical subjects

Satoshi Sasaki

Publications and source records attributed to Satoshi Sasaki.

At least 37 records · Page 2Linked to original sources

PubMed2006

Control of the bioluminescence starting time by inoculated cell density.

In this study, we attempted to control the timing of light-emission from bioluminescent bacteria, by changed cell numbers inoculated into medium. Luminous bacteria express bioluminescence when the number of cells reached a threshold. Inoculated cell density had an effect on the time of bioluminescence starting. Samples were prepared by varying cell density of inoculation. In the results, all the vials showed different luminescence profiles in the order of inoculated cell population.

Animals↗

PubMed2006

Periodical bubble formation and the oscillatory change in dissolved oxygen concentration in a catalase-hydrogen peroxide system.

The relationship between the periodical bubble forming and the oscillatory change in the dissolved oxygen (DO) concentration in a catalase-hydrogen peroxide system was studied. Photographs of the bubbles and the responses from the DO electrode indicated that large bubbles were generated periodically, and that the DO profile depended on the geometrical relationship between the electrode and the bubbles.

Animals↗

PubMed2006

Eating fast leads to obesity: findings based on self-administered questionnaires among middle-aged Japanese men and women.

BACKGROUND: Few epidemiologic studies have examined the association between the rate of eating and obesity. In this study, we cross-sectionally examined the association of the self-reported rate of eating with current Body Mass Index (BMI), and BMI-change from 20 years of age to the current age. METHODS: Subjects were 3737 male (mean age +/- standard deviation and mean BMI +/- standard deviation: 48.2 +/- 7.1 years and 23.3 +/- 2.7 kg/m(2)) and 1005 female (46.3 +/- 7.0 years and 21.8 +/- 2.8 kg/m(2)) Japanese civil servants. We measured self-reported categorical rate of eating, current BMI, BMI at age 20, and BMI-change from age 20. Energy intake was assessed over a 1-month period with a brief-type diet history questionnaire. RESULTS: The multiple regression analysis in which the current BMI was regressed by categorical rate of eating, energy intake, age, and lifestyle factors showed that current BMI steadily increased by -0.99, -0.67, 0.81, and 1.47 kg/m(2) along with the progress of categorical rate of eating from the 'medium' group to 'very slow', 'relatively slow', 'relatively fast', and 'very fast' groups, respectively, in men. In women, the corresponding values were -1.06, -0.35, 0.50, and 1.34 kg/m(2). When the BMI increment from age 20 to current age was regressed in the same manner, the increment was -0.63, -0.34, 0.57, and 1.05 kg/m(2) in men and -0.71, -0.32, 0.34, and 1.14 kg/m(2) in women, respectively. Additionally, both BMI at age 20 and current height were positively associated with rate of eating. CONCLUSIONS: Our results among middle-aged men and women suggest that eating fast would lead to obesity.

Adult↗

PubMed2006

[Calcium, magnesium, and potassium as dietary nutrients].

This review summarized recent epidemiologic studies on three minerals (calcium magnesium, and potassium) of which relation to osteoporosis and bone fracture has been suggested. A significant relation with bone mineral density (BMD) and bone fracture was generally found in low calcium intake populations such as Chinese. But few studies found a significant relation in Western populations. For magnesium and potassium, some studies found a significantly positive relation with BMD. But no study with bone fracture as outcome has yet existed.

Bone Density↗

PubMed2005

Dioxin concentration in human milk in Hebei province in China and Tokyo, Japan: potential dietary risk factors and determination of possible sources.

Very limited information is available on body burdens and environmental levels of dioxins and dioxin-like PCBs (dl-PCBs) in mainland China. In the current studies, human milk samples were collected from 30 breastfeeding mothers in Shijiazhuang city (industrialized) and 11 in the Tanshan countryside (agricultural) of Hebei Province in northern China. An additional 20 samples were obtained from mothers in Tokyo, Japan. PCDDs, PCDFs, and dl-PCBs in human milk were analyzed by high-resolution gas chromatography/high-resolution mass spectrometry. Our results show that arithmetic means for body burdens of PCDDs/Fs and dl-PCBs in Hebei were 3.6 and 1.9 pg TEQg(-1) fat, respectively, which were only about one fourth of the levels in Japan. In addition, no difference was found in the chemical levels except dl-PCBs between the urban and rural areas. Based on the results of an in-person interview of the Chinese mothers using a 59-item questionnaire, freshwater fish consumption was found to correlate with the body burden of dioxins. Principal component analysis of dioxin congeners revealed that the patterns of dioxins in the Hebei urban and rural areas are quite similar; however, they are clearly different from those in Japan. Collectively, our results suggest that the lower body burdens of dioxin in Hebei may be due in part to the relatively slow industrialization and a lower consumption of marine foods. Finally, the results indicate that comprehensive monitoring of dioxins and dl-PCBs in humans as well as in the environment and foods is necessary in China.

Adult↗

PubMed2005

Responses of Bruguiera gymnorrhiza to saltwater monitored by miniature electrodes.

We measured the voltage between two Ag/AgCl electrodes, one inserted into the seedling of the salt-tolerant plant Bruguiera gymnorrhiza and the other into the vermiculite in which the seedling was potted. Four seedlings were placed in different environments, in saltwater or pure water, with light or alternating light/dark conditions. We have found that (1) the voltage profiles showed periodical oscillatory behavior; (2) seedlings in saltwater showed higher voltage compared to the ones in pure water; (3) in the light environment, the voltage was higher compared to the one in the dark environment; (4) in the dark environment, a voltage wave was hardly observable; and (5) electrodes inserted into the propagule cortex, stem cortex, and petiole showed different voltage wave amplitudes. The voltage profiles will provide an effective way to evaluate the movement of salt water inside the salt-tolerant plant.

Biosensing Techniques↗

PubMed2005

Dietary patterns and subsequent colorectal cancer risk by subsite: a prospective cohort study.

In order to investigate the associations between dietary patterns and the risk of colorectal cancer by subsite in Japan, the baseline data from a population-based cohort study of 20,300 men and 21,812 women were analyzed. We conducted factor analysis and identified 3 major dietary patterns, "healthy," "traditional" and "Western," and calculated the factor scores of each pattern for individuals. During 10 years of follow-up, 370 colorectal cancer cases were identified. We found a positive association between the traditional pattern and colon cancer risk in women [rate ratio for highest quartile (RR) = 2.06; 95% CI = 1.10-3.84; p for trend = 0.11], but not in men. This positive association was slightly stronger for proximal colon cancer (RR = 2.07; 95% CI = 0.84-5.12) than for distal colon cancer (RR = 1.84; 95% CI = 0.75-4.50). After multivariate adjustment, the Western dietary pattern was also positively associated with colon cancer risk in females (RR = 2.21; 95% CI = 1.10-4.45), with the strongest associations being observed for females with distal colon cancer (RR = 3.48; 95% CI = 1.25-9.65). We did not observe any significant association between the healthy dietary pattern and colon cancer risk. For rectal cancer, no significant associations were found for the 3 dietary patterns. In conclusion, we found that the traditional and the Western dietary patterns were positively associated with colon cancer risk in females.

Adult↗

PubMed2005

Copper reduction by the octapeptide repeat region of prion protein: pH dependence and implications in cellular copper uptake.

The physiological function of the prion protein (PrP) remains enigmatic despite its established involvement in the pathogenesis of spongiform encephalopathies. PrP is a glycolipid-anchored membrane protein, which constitutively recycles between the cell surface and an endosomal compartment. The N-terminal region of PrP contains a four tandem repeat (OP4) of the octapeptide PHGGGWGQ (OP) that binds and reduces Cu(II) ions. We have examined the kinetic properties of the OP4-mediated Cu(II) reduction and found that OP4 exhibits the highest reduction activity around pH 6.5, close to the pH in early endosomes. All four OP units and at least one tryptophan side chain are essential for Cu(II) reduction. The reaction is described by an uncompetitive substrate inhibition mechanism involving a 1:1 Cu(II)-OP4 active intermediate. Structural analysis by Raman spectroscopy has revealed that the Cu(II) ion is coordinated by four histidine Ntau atoms in the active intermediate and the feasibility of formation of this intermediate correlates with the Cu(II) reduction over a pH range from 5.0 to 8.2. Molecular mechanics calculations suggest that two tryptophan residues of OP4 are located near the Cu(II) site, being consistent with the importance of redox-active tryptophan in the Cu(II) reduction. PrP has been proposed to capture Cu(II) ions in the extracellular space and release them in the endosome. The results of this study strongly suggest that PrP also plays a role in the reduction of captured Cu(II) ions prior to their transfer to Cu(I)-specific intracellular copper trafficking proteins.

Amino Acid Sequence↗

PubMed2005

Active and passive smoking and breast cancer risk in middle-aged Japanese women.

To examine the hypothesis that tobacco smoke is associated with the risk of female breast cancer, we estimated the relative risks of active and passive smoke in middle-aged Japanese women in a population-based prospective study. The cohort consisted of residents in 4 public health center areas, aged 40 to 59 years. A self-administered questionnaire survey was conducted in 1990. This analysis included 21,805 subjects, 180 of whom had developed breast cancer by December 31, 1999. When the reference was defined as never-active smokers without passive smoking, adjusted relative risks (RRs) were 1.9 (95% confidence interval [CI] = 1.0-3.6) in current active smokers, 1.2 (95% CI = 0.4-4.0) in ex-active smokers and 1.2 (95% CI = 0.8-1.6) in never-active smokers with passive smoking. The elevated risk for ever-smokers was clearly observed in premenopausal women at baseline (RR = 3.9, 95% CI = 1.5-9.9) but not in postmenopausal women (RR = 1.1, 95% CI = 0.5-2.5). In never-active smokers, the adjusted RR for passive smoking, residential or occupational/public tobacco smoke exposure was 1.1 (95% CI = 0.8-1.6). In premenopausal women, passive smoking increased the risk (RR = 2.6; 95% CI = 1.3-5.2) but not in postmenopausal women (RR = 0.7; 95% CI = 0.4-1.0). We conclude that tobacco smoking increases the risk of female breast cancer in premenopausal women.

Breast Neoplasms↗

PubMed2005

Cytologic factors associated with prognosis in patients with peripheral adenocarcinoma of the lung measuring 3 cm or less in greatest dimension.

BACKGROUND: Recently, peripheral lung adenocarcinomas (PLA) measuring < or = 3 cm in greatest dimension often have been diagnosed using diagnostic radiology. The objective of the current study was to determine which cytologic factors are associated with a favorable outcome and an unfavorable outcome in patients with PLA. METHODS: Imprint smears from 134 patients with PLA were examined. Sixteen cytologic factors, including necrosis, cellular distribution, overlapping of cell clusters, cluster aggregation, cluster size, cluster thickness, nuclear irregularity, nuclear size, variation in nuclear size, multinucleated cells, intranuclear inclusions, type of intranuclear inclusions, appearance of nucleoli, eosinophilic nucleoli, multinucleoli, and mitosis, were evaluated using univariate and multivariate analyses. A counting method was used to determine the prognosis for individual patients. RESULTS: In the univariate analysis, a cluster size that measured > or = 831 microm in short dimension (P = 0.0011), moderate or severe nuclear irregularity (P = 0.0030), > or = 5 multinucleated cells per 100 tumor cells (P = 0.0047), moderate or severe variation in nuclear size (P = 0.0061), medium or large nuclear size (P = 0.0169), and > or = 1 mitotic cell per 100 tumor cells (P = 0.0412) were associated significantly with a poor outcome. In the multivariate analysis, cluster size in short dimension (P = 0.0018), multinucleated cells (P = 0.0066), and nuclear irregularity (P = 0.0310) were found to be independent prognostic factors. CONCLUSIONS: The combination of cytologic features using intraoperative imprint smears, namely, cluster sizes < or = 830 microm in short dimension, < or = 4 multinucleated cells per 100 tumor cells, and mild nuclear irregularity, may provide favorable predictive information in patients with PLA.

Adenocarcinoma↗

PubMed2005

Glomerular localization of erythropoietin receptor mRNA and protein in neonatal and mature mouse kidney.

BACKGROUND/AIMS: Erythropoietin (EPO) possesses well-established hematopoietic properties as the primary stimulator of red blood cell formation by binding to its receptor (EPO-R). Recent evidence suggests pathophysiological roles of EPO in several non-hematopoietic tissues including kidney. Our aim was to further clarify the glomerular localization of EPO-R in normal kidney, as well as changes in its expression during glomerulogenesis. METHODS: We analyzed EPO-R mRNA and protein expression in neonatal and adult mouse kidney by in situ hybridization and immunohistochemistry. To confirm the precise localization and developmental changes of EPO-R expression in podocytes in mature and developing glomeruli, we examined co-expression with the podocyte markers WT-1 and synaptopodin. RESULTS: In addition to tubular expression as reported recently, EPO-R expression was observed in podocytes as well as endocapillary cells in the glomeruli from adult mice. In newborn kidney, EPO-R mRNA and protein expression was first observed in developing podocytes in S-shaped bodies with expression subsequently increasing in glomeruli at the capillary-loop and maturing stages. Immunoelectron microscopy also demonstrated cytoplasmic expression of EPO-R that was prominent at the basal sides of podocytes in glomeruli at the late capillary-loop and maturing stage. CONCLUSION: EPO-R is expressed in developing and mature podocytes in mouse kidney, suggesting a possible role for EPO in podocyte biology.

Animals↗

PubMed2005

Occupational and environmental factors and idiopathic pulmonary fibrosis in Japan.

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrosing interstitial lung disease of unknown etiology. Environmental factors, especially occupational agents, may be of great importance in the manifestation of IPF. We examined the relationship between occupational and environmental factors and IPF in Japan. A multicenter hospital-based case-control study was performed in 2001. Included were 102 cases aged 40 years or over who were within 2 years of having been diagnosed in accordance with the most recent criteria. Controls, aged 40 years or over, were 55 hospitalized patients diagnosed as having acute bacterial pneumonia and four outpatients with common colds. Data on occupational and environmental factors were obtained from a questionnaire. Multiple logistic regression analysis was used to estimate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of IPF for single factors with adjustment for age, sex and region. Compared with controls, cases were more likely to have been managers, officials or production workers and less likely to have been protective service or materials handling workers. Clerical and related work was significantly related to a decreased risk of IPF after further adjustment for pack-years of smoking (OR = 0.42; 95% CI = 0.18-0.95). Exposure to metal dust was significantly associated with an increased risk of IPF (OR = 9.55; 95% CI = 1.68-181.12). From 20.0 to 39.9 pack-years of smoking was significantly associated with an increased risk of IPF (OR = 3.23; 95% CI = 1.01-10.84). Our results appear to confirm data from previous epidemiologic studies. Metal dust exposure may be a particularly important risk factor for IPF.

Adult↗

PubMed2005

Primary gastric choriocarcinoma: two case reports and a pooled analysis of 53 cases.

Primary gastric choriocarcinoma (PGC) is a rare tumor. In total, approximately 140 cases of PGC have been reported in the international medical literature. However, the clinical behavior, tumor characteristics, and prognostic parameters of PGC have not been clearly described. We conducted a pooled analysis to clarify the tumor characteristics and prognostic parameters in 53 patients with PGCs, including 2 patients treated at our hospital. The following variables were examined as potential prognostic factors: (1) sex, (2) age, (3) depth of invasion, (4) size, (5) histology, (6) nodal metastasis, (7) distant lymph node metastasis, (8) synchronous liver metastasis, (9) residual tumor, and (10) chemotherapy (not given or given). Univariate and multivariate analyses showed that the presence of residual tumor and synchronous liver metastasis and the absence of chemotherapy were significantly associated with an increased hazard rate (HR) of short overall survival (OS). Pooled analysis, including the two patients with PGC treated at our facility, demonstrated that the presence of a curative operation and chemotherapy, and the absence of synchronous liver metastasis were the strongest indicators of a favorable clinical course in patients with PGC.

Adenocarcinoma↗

PubMed2005

Active and passive smoking and tooth loss in Japanese women: baseline data from the osaka maternal and child health study.

PURPOSE: Many studies have shown a positive association between cigarette smoking and oral diseases. Few studies, however, have focused on the relationship between passive smoking exposure and oral health in adults. We investigated the association of active and passive smoking exposure with tooth loss in Japan. METHODS: Study subjects were 1002 pregnant women. Tooth loss was defined as previous extraction of one or more teeth. Adjustment was made for age, gestation, parity, family income, education, and body mass index. RESULTS: Of the 1002 subjects, 256 women had lost one or more teeth. Current light smoking was independently related to an increased prevalence of tooth loss, showing a significant exposure-related association with smoking status. A significant positive association of 8 or more pack-years of smoking with the prevalence of tooth loss was observed. Also, a significant positive relationship was found between current heavy passive smoking at home and tooth loss, but not with pack-years of passive smoking at home. No measurable association between passive smoking exposure at work and tooth loss was indicated. CONCLUSIONS: The present findings suggest that passive as well as active smoking may be associated with an increased prevalence of tooth loss in Japanese young adult women.

Adult↗

PubMed2005

Environmental exposure to cadmium at a level insufficient to induce renal tubular dysfunction does not affect bone density among female Japanese farmers.

Some recent research suggests that environmental exposure to cadmium, even at low levels, may increase the risk of osteoporosis, and that the bone demineralization is not just a secondary effect of renal dysfunction induced by high doses of cadmium as previously reported. To investigate the effect of exposure to cadmium at a level insufficient to induce kidney damage on bone mineral density (BMD) and bone metabolism, we conducted health examinations on 1380 female farmers from five districts in Japan who consumed rice contaminated by low-to-moderate levels of cadmium. We collected peripheral blood and urine samples and medical and nutritional information, and measured forearm BMD. Analysis of the data for subjects grouped by urinary cadmium level and age-related menstrual status suggested that cadmium accelerates both the increase of urinary calcium excretion around the time of menopause and the subsequent decrease in bone density after menopause. However, multivariate analyses showed no significant contribution of cadmium to bone density or urinary calcium excretion, indicating that the results mentioned above were confounded by other factors. These results indicate that environmental exposure to cadmium at levels insufficient to induce renal dysfunction does not increase the risk of osteoporosis, strongly supporting the established explanation for bone injury induced by cadmium as a secondary effect.

Agriculture↗

PubMed2005

Soy, isoflavones, and prevalence of allergic rhinitis in Japanese women: the Osaka Maternal and Child Health Study.

BACKGROUND: It has been hypothesized that isoflavones reduce the risk of many chronic diseases, but there are no data on the effects of dietary soy and isoflavone consumption on allergic disorders. OBJECTIVE: This cross-sectional study examined the relationship between dietary soy products and isoflavone intake and the prevalence of allergic rhinitis. METHODS: Study subjects were 1002 Japanese pregnant women. Allergic rhinitis (including cedar pollinosis) was defined as present if subjects had received drug treatment at some point during the previous 12 months. Adjustment was made for age; gestation; parity; cigarette smoking; passive smoking at home and at work; indoor domestic pets; family history of asthma, atopic eczema, and allergic rhinitis; family income; education; mite allergen level in house dust; changes in diet in the previous month; season when data were collected; and body mass index. RESULTS: Compared with dietary intake of total soy product, soy protein, daidzein, and genistein in the first quartile, consumption of these substances in the fourth quartile was independently associated with a reduced prevalence of allergic rhinitis, although no significant dose-response relationships were observed. A clear inverse linear trend for miso intake across quartiles was found, whereas the adjusted odds ratio for comparison of the highest with the lowest quartile was not statistically significant. Consumption of tofu, tofu products, fermented soybeans, boiled soybeans, and miso soup was not related to the prevalence of allergic rhinitis. CONCLUSION: A high intake of soy and isoflavones may be associated with a reduced prevalence of allergic rhinitis.

Adult↗

PubMed2005

Association of active and passive smoking with allergic disorders in pregnant Japanese women: baseline data from the Osaka Maternal and Child Health Study.

BACKGROUND: Evidence remains inconclusive as to whether smoking is a risk factor for allergic disorders in adults. OBJECTIVE: To investigate the relationship between active and passive smoking exposure and allergic disorders in pregnant Japanese women. METHODS: This cross-sectional study included 1,002 pregnant women. Participants were classified as having asthma after the age of 18 years if they had used an asthma medication at any time after reaching the age of 18 years. Current atopic eczema and allergic rhinitis (including cedar pollinosis) were defined as being present if participants had received any drug treatment during the previous 12 months. Adjustment was made for age; gestation; parity; family history of asthma, atopic eczema, and allergic rhinitis; indoor domestic pets; family income; education; and the mite antigen level in house dust. RESULTS: Current smoking, but not environmental tobacco smoke exposure, was independently related to an increased prevalence of asthma after the age of 18 years (adjusted odds ratio [OR], 2.66; 95% confidence interval [CI], 1.30-5.38). A significant positive association of current passive smoking exposure at home (adjusted OR, 1.89; 95% CI, 1.10-3.30) and at work (adjusted OR, 2.50; 95% CI, 1.29-4.76) with the prevalence of current allergic rhinitis was observed, whereas no measurable association with active smoking exposure was found. Neither active nor passive smoking was statistically significantly related to the prevalence of current atopic eczema. CONCLUSIONS: These findings suggest that active smoking and environmental tobacco smoke exposure may increase the likelihood of asthma and allergic rhinitis, respectively, in pregnant Japanese women.

Adolescent↗

PubMed2005

Anaemia, iron deficiency and vitamin A status among school-aged children in rural Kazakhstan.

OBJECTIVES: To investigate the prevalence of anaemia and iron deficiency and vitamin A status among school-aged children in rural Kazakhstan and identify factors associated with anaemia in this population. DESIGN: A cross-sectional design. SETTING: School-aged children in rural Kazakhstan. SUBJECTS: Socio-economic and anthropometric information was collected from 159 school-aged children living in the Kzyl-Orda region of Kazakhstan. Blood samples were collected and the concentrations of haemoglobin (Hb), serum iron, serum ferritin (SF), erythrocyte protoporphyrin (EP), serum retinol and beta-carotene, total iron binding capacity (TIBC), transferrin saturation (TS) and other haematological indices were measured. RESULTS: Among the 159 children, the prevalence of anaemia and iron deficiency defined by the multiple criteria model (SF, TS and EP) was 27% and 13%, respectively. Nine per cent had iron-deficiency anaemia and 21% had serum retinol value < 1.05 micromol l(-1). Mean SF and serum iron concentrations and TS were significantly lower in anaemic children than in their non-anaemic peers, while TIBC and EP were significantly higher in children with anaemia. Hb was significantly correlated with serum iron and retinol concentrations. Serum retinol and SF concentrations and mean corpuscular volume were significantly correlated with Hb by multiple regression analysis. CONCLUSIONS: Anaemia among school-aged children in rural Kazakhstan appears to be related to iron indices and vitamin A status.

Adolescent↗