Biomedical subjects

Tadashi Shimoyama

Publications and source records attributed to Tadashi Shimoyama.

12 recordsLinked to original sources

PubMed2003

Environmental factors affect colon carcinoma and rectal carcinoma in men and women differently.

BACKGROUND AND AIMS: Colon cancer is thought to be more closely associated with environmental factors than rectal cancer, but evidence is currently insufficient. We examined whether there are differences in the degree of environmental effect on colon cancer and rectal cancer in Japan. METHODS: We performed a birth cohort analysis for colon and rectal cancers using Japanese vital statistics from 1950 to 1998 and analyzed time trends by cancer site and gender. RESULTS: The mean annual increase in age-adjusted mortality rate from colon cancer was greater than that from rectal cancer and was greater in men than in women. In men left colon cancer showed the greatest rate of increase whereas cancer of the right colon showed only a slight change. Although left colon cancer rapidly increased until the middle 1980s and thereafter showed no change, right colon cancer showed no change until the middle 1980s and thereafter rapidly increased in men. However, the rates of increase in left colon cancer were greater than those in right colon cancer until the middle 1980s, after which a reversal in trend was seen in women. Birth cohort analysis indicates that for all cohorts the mortality rates at the same age were higher in the recent cohorts than in the previous ones. This trend was more marked for colon cancer than for rectal cancer and was stronger among men than among women. CONCLUSION: Colon cancer is more closely associated than rectal cancer with environmental factors, and this association is more pronounced in men than in women. Consequently cancers at these two sites should not be combined in studies of the role of lifestyle factors in causing these neoplasms. Furthermore, the causes of these diseases may differ in men and women.

Adolescent↗

PubMed2003

Low-level laser irradiation attenuates production of reactive oxygen species by human neutrophils.

OBJECTIVE: The aim of this study was to examine the effects of low-level laser therapy (LLLT) on production of reactive oxygen (ROS) species by human neutrophils. BACKGROUND DATA: LLLT is an effective therapeutic modality for inflammatory conditions. MATERIALS AND METHODS: The laser device used was the infrared diode laser (GaAlAs), 830-nm continuous wave (150 mW/cm(2)). After irradiation, ROS production by neutrophils was measured using luminol-dependent chemiluminescence (LmCL) and expression of CD11b and CD16 on neutrophil surface was measured by flow cytometry. RESULTS: The LmCL response of neutrophils was reduced by laser irradiation at 60 min prior to the stimulation with opsonized zymosan and calcium ionophore. The attenuating effect of LLLT was larger in neutrophils of smokers than non-smokers, while the amount of produced ROS was larger in neutrophils of smokers. Expression of CD11b and CD16 on neutrophil surface was not affected by LLLT. CONCLUSION: Attenuation of ROS production by neutrophils may play a role in the effects of LLLT in the treatment of inflammatory tissues. There is a possible usage of LLLT to improve wound healing in smokers.

Adult↗

PubMed2003

The resistant starch level of heat moisture-treated high amylose cornstarch is much lower when measured in the human terminal ileum than when estimated in vitro.

According to the definition of resistant starch (RS), the true value of foodstuff-derived RS can be assessed only from that found in the contents of the terminal ileum. To date, a few methods exist for in vivo measurement of RS in the terminal ileum, but their accuracy is questionable. The aim of this study was to quantify the level of RS in the terminal ileum to determine its true value as dietary fiber (DF). Volunteers (n = 7 men) were given a test meal containing 10 g of heat moisture-treated high amylose cornstarch (HMT-HAS) containing 8.8 g of RS as measured by Englyst's method. A double-lumen tube was positioned in the terminal ileum using the endoscopic retrograde bowel insertion method (ERBI). Intestinal contents were aspirated, and the amount of RS was measured as the glucose concentration (Englyst's method), and compared with the values for RS administrated orally using the same method. The mean amount of HMT-HAS-derived RS collected in the terminal ileum was 3.37 +/- 0.95 g (mean +/- SD), which was 34.5 +/- 9.7% of the in vitro RS value. Furthermore, there were large individual differences in recoveries, ranging from 22.2 to 47.5%. The measured amount of HMT-HAS-derived RS was much smaller in our in vivo study than that measured in vitro, suggesting that in vitro measurement may inaccurately estimate the RS and DF levels of foodstuffs. The problem is further compounded by the large individual in vivo variations in RS values from subjects consuming identical diets.

Adult↗

PubMed2003

No preventive effect of dietary fiber against colon cancer in the Japanese population: a cross-sectional analysis.

The report of Fuchs et al. in 1999 on the protective effects of dietary fiber (DF) against colon carcinogenesis has led many researchers to question the benefits of DF. We analyzed the relationship between dietary intake and mortality from colon cancer in Japan cross-sectionally. Dietary data were taken from the National Nutrition Survey. The standardized mortality ratio (SMR) was calculated using data from "Vital Statistics" and "the Population Census in Japan." Multiple regression analysis (stepwise variable selection method) was performed with the SMR of colon cancer as the objective variable and intake of DF, nutrients, and food groups in 1966 as the explanatory variables. The beta regression coefficient was significantly positive for intakes of fat, protein, and vitamin C and significantly negative for intakes of calcium and vitamin A to the SMR of colon cancer. However, no significant correlation was observed for DF or for any of the various food groups analyzed. In conclusion, our data do not demonstrate any protective effect of DF on colon cancer in subjects with a low fat intake (Japanese subjects), which supports Fuchs' findings in subjects with high fat intake (U.S. subjects).

Colonic Neoplasms↗

PubMed2003

Characteristics of attenuating effects of rebamipide, an anti-ulcer agent, on oxidative burst of human neutrophils.

The aim of this study was to characterize the effects of rebamipide on the oxidative burst of human neutrophils. The neutrophil oxidative burst was measured in the presence of rebamipide and cimetidine using lucigenin- or luminol-dependent chemiluminescence (LgCL or LmCL). Rebamipide inhibited the LmCL response stimulated with opsonized zymosan, 12-myristate 13-acetate phorbol, and calcium ionophore in a dose-dependent manner, but the LgCL response was inhibited when neutrophils were stimulated with opsonized zymosan. LmCL response was also dose-dependently attenuated by rebamipide even in the presence of cimetidine. Thus, addition of rebamipide to H(2)-receptor antagonists can be considered for the treatment of gastric mucosal injury associated with oxidative stress.

Adult↗

PubMed2002

Relationship between lifestyle factors and defecation in a Japanese population.

BACKGROUND: There is a paucity of accurate data regarding any association in the general population between defecation and lifestyle factors such as diet, exercise, physique, and childbirth. AIMS OF THE STUDY: To evaluate the effects of such lifestyle factors on defecation among regional residents of Japan. METHODS: Residents (n = 1,699) of northern Japan, aged over 40 years, were surveyed in 1995 using a questionnaire to assess their lifestyle factors (diet, beverage consumption, exercise, physique, and childbirth), and examining their defecation status. We evaluated the relationship between these lifestyle factors and defecation using logistic regression analysis. The authors used four measures (defecation frequency, subjective defecation state, subjective fecal properties, and fecal consistency) and assigned the subjects to a group defined by their defecatory status: constipation, diarrhea, or normal, depending on the responses of the subjects to all four criteria. RESULTS: The tendency for constipation correlated positively with age in males ( p = 0.130), although this trend was not observed in females ( p = 0.641). Of the dietary factors examined, only rice, which accounts for the largest proportion of daily dietary fiber intake in Japan, demonstrated a preventive effect on constipation in both sexes ( p = 0.050 in males and 0.003 in females). Walking was a preventive factor for constipation among males ( p = 0.049), and alcohol also inhibited constipation among males ( p = 0.007). CONCLUSIONS: These results suggest that exercise, such as walking, and a high intake of dietary fiber, such as rice, were useful in the maintenance of defecation.

Adult↗

PubMed2002

Production of chemokines and reactive oxygen species by human neutrophils stimulated by Helicobacter pylori.

BACKGROUND: Bacteria have different characteristics in stimulation of human neutrophils to produce reactive oxygen species (ROS) and chemokines. This study examined the ability of Helicobacter pylori to induce production of ROS and chemokines by human neutrophils. METHODS: H. pylori strains (1.5 x 108 CFU/ml) were cocultured with 5 x 104 neutrophils isolated from healthy subjects. Samples were incubated with human serum with or without IgG antibodies to H. pylori. ROS production was measured using luminol-dependent chemiluminescence (LmCL), and the concentrations of chemokines (IL-8, RANTES, MIP-1alpha and MCP-1) were measured by ELISA. RESULTS: The mean of the highest LmCL (peak height; PH) value stimulated by H. pylori was 3318 in the absence of serum. PH increased to 4687 when incubated with anti-H. pylori antibody-positive sera (p <.001) but antibody-negative sera did not affect LmCL response. The mean final concentration of IL-8 produced in the absence of serum was 142.6 pg/ml. Increased IL-8 production was seen by addition of antibody positive serum (p <.01). IL-8 production was not significantly correlated with production of ROS. On the other hand, H. pylori stimulation did not induce neutrophil production of RANTES, MIP-1alpha or MCP-1. CONCLUSIONS: H. pylori was capable of inducing IL-8 production by human neutrophils, but not C-C chemokines. Production of C-X-C dominant chemokine by neutrophils is consistent with the pathological characteristics of H. pylori-induced gastritis, where persistent neutrophil infiltration is present.

Cells, Cultured↗

PubMed2002

Cyclooxygenase-2 expression is increased in early intestinal-type gastric cancer and gastric mucosa with intestinal metaplasia.

OBJECTIVE: Cyclooxygenase-2 (COX-2) expression is increased in gastric cancer. We examined COX-2 expression in early stage gastric cancer and background mucosa to elucidate the role of COX-2 in gastric carcinogenesis. METHODS: Thirty-three early gastric cancers obtained from 30 patients infected with Helicobacter pylori were studied. Twenty-three patients had an intestinal, four patients had a diffuse, and three patients had both an intestinal and a diffuse type cancer. Expression of COX-2 protein was detected by immunohistochemistry by counting the number of positive staining cells per 100 cells. RESULTS: Mean COX-2 expression was 84.1 (SD 11.4) in 26 intestinal type cancers and was significantly higher than that in seven diffuse type cancers (23.1 +/- 9.7) (P < 0.001). In three patients who had both the intestinal and the diffuse type cancer, COX-2 expression was 92, 90 and 83 in the intestinal type cancer and only 25, 24 and 7 in the corresponding diffuse type cancer. In 18 patients who had intestinal metaplasia (15 had incomplete metaplasia), COX-2 expression was 60.2 (24.2) in the crypts with metaplasia while it was only 16.8 (10.7) in the crypts without metaplasia (P < 0.001). CONCLUSIONS: COX-2 expression may be associated with the carcinogenesis of the intestinal type gastric cancer and, speculatively, inhibition of COX-2 might have preventative effects on the intestinal type gastric cancer.

Cyclooxygenase 2↗

PubMed2002

[Rebamipide].

Explore the source record for details and available documents.

Alanine↗

PubMed2000

Differences in Lifestyle of a Smoking and Non-smoking Population in Japan.

If smokers have different lifestyle including dietary habit in comparison to non-smokers, this difference have an influence on the evaluation of the risks of smoking for tobacco-related diseases or the design of anti-smoking campaigns. In Japan, 1,745 men over the age of 40 were surveyed regarding health consciousness in 1996 and 2,136 men between the ages of 50 and 65 were surveyed regarding dietary habits in 1993-1994. Comparative analysis was done among the smoking and non-smoking groups. The rate of participation in cancer mass-screening for smokers was significantly lower than for non-smokers. Smokers had consumed significantly lower amounts of vegetables, fruits and beans, which are well known beneficial factors for health than non-smokers, and had consumed more salt, salty food and alcohol, which are well known risk factors for health. It is suggested that smokers have disadvantageous characteristics for promoting and maintaining a healthy lifestyle more than in non-smokers. Accordingly, to evaluate the risk of smoking for tobacco-related diseases in epidemiological researches, we should properly treat these data as confounding factors. Furthermore, anti-smoking campaigns should be performed considering these differences.

Journal Article↗

PubMedDate not supplied

Effects of long-distance running on serum opsonic activity measured by chemiluminescence.

Exhaustive exercise such as long-distance running has been shown to increase susceptibility to infection. In order to investigate whether serum opsonic activity plays a role in such conditions, we utilized luminol-dependent and lucigenin-dependent chemiluminescence (LmCL and LgCL). We took serum samples from 24 male marathon runners before and after running 30 km. Neutrophils were isolated from the peripheral blood of healthy volunteers. Serum opsonic activity was examined by measuring neutrophil ROS stimulated with zymosan particles opsonized by the serum samples. Immunoglobulin and complement levels in the serum were also measured. After a 30 km run, the maximum light emission was increased and the time to reach the maximum light emission was shortened significantly (p < 0.05) in LmCL. However, there were no significant changes in the immunoglobulin and complement levels. The increase of ROS production may suggest that serum opsonic activity is accelerated after running 30 km. Thus, serum opsonic activity might not play a significant role in the susceptibility to infection after long-distance running.

Acridines↗

PubMedDate not supplied

Effects of weight reduction on neutrophil phagocytic activity and oxidative burst activity in female judoists.

This study investigated the effects of short-term weight reduction on neutrophil functions in female judoists. Sixteen actively competing female judoists were divided into two groups. Eight who required weight reduction were defined as the weight reduction group, and the remaining eight were used as the control. Blood samples were taken before, immediately after and 8 days after the match. Phagocytic activity and oxidative burst activity of neutrophils were measured by flow cytometry. In the weight reduction group, the phagocytic activity per cell decreased significantly at the end of weight reduction compared with the control group. The rate of neutrophils producing reactive oxygen species and the oxidative burst activity per cell increased significantly at the end of weight reduction in both the control and the weight reduction groups. We concluded that weight reduction, consisting of both intense exercise and energy restriction, might possibly cause both an increase in oxidative burst activity and decrease in neutrophil phagocytic activity in female judoists. However, although exercise increased oxidative burst activity, it did not affect neutrophil phagocytic activity alone. Therefore, to avoid this problem, female judoists are recommended to keep their weight within those limits determined by their class, and which can be reduced by exercise.

Blood Cell Count↗