Effects of 2.5-hour sumo training on serum opsonic activity.

Sumo is a traditional Japanese sport, but the effect of actual daily training on neutrophil function is unknown. We evaluated the effect of sumo training on serum opsonic activity (SOA), which is one of the main neutrophil-related functions. Seventeen male university sumo wrestlers participated in the study. Changes in anthropometric parameters, concentrations of serum immunoglobulins (IgG, IgA and IgM), complements (C3 and C4), myogenic enzymes (lactate dehydrogenase, asparate aminotransferase, alanine aminotransferase and creatine kinase), white blood cell/neutrophil counts and SOA were measured immediately before and after actual daily training for 2.5 h. Compared with the pre-values, immunoglobulins and complements, myogenic enzymes and white blood cell/neutrophil counts significantly increased (p < 0.01 for all). As for SOA, the values of the peak height and the area under the curve significantly increased after the training when assessed using lucigenin as a chemiluminigenic probe (p < 0.01 for all), but showed no significant change when luminol was used as the chemiluminigenic probe. In conclusion, daily actual sumo training for 2.5 h increases SOA, thus possibly activating the reactive oxygen species production of neutrophils.

Are individuals with lower neutrophil oxidative burst activity more prone to Helicobacter pylori infection?

Helicobacter pylori infection has been reported to cause enhanced reactive oxygen species in the gastric mucosa. We examined the relationship between H. pylori infection and neutrophil function of peripheral blood. The subjects were 904 volunteers who participated in the Iwaki Health Promotion Project in 2005. 158 subjects who were infected with H. pylori in 2005 also participated in this project in 2006 and were categorized into two groups: the eradication group, in which H. pylori was successfully eradicated during the 12 month period, and the non-eradication group, in which eradication was unsuccessful or the subjects did not receive eradication therapy. The laboratory assays performed were: a titre of H. pylori antibody; neutrophil counts; and oxidative burst activity (OBA) of neutrophils. Logistic regression analysis was executed, with H. pylori infection as the dependent variable and other items as the independent variables. OBA showed an inverse association with H. pylori infection in 2005. Additionally, when comparing the eradication and non-eradication groups, the change rates of OBA between 2005 and 2006 did not show any significant difference. It was concluded that H. pylori infection does not lower OBA, but those individuals in whom OBA was lower were more prone to H. pylori infection.

Measuring neutrophil functions might be a good predictive marker of overtraining in athletes.

In order to develop a predictive marker of overtraining in athletes, we examined the changes in neutrophil function [reactive oxygen species (ROS) production capability and phagocytic activity (PA)] for 10 male and 13 female judoists attending a training camp. Measurements were taken four times in total--immediately before and after a 2 h unified exercise loading (UEL) performed 1 day before (Pre-Camp) and the day after the 7 day training camp (Post-Camp). UEL-mediated aspartate aminotransferase was higher at Post-Camp than at Pre-Camp in females but not in males. Post-Camp leukocyte/neutrophil counts after the UEL significantly increased in females but not in males. The rate of change in C4 was significantly smaller in females than in males at Post-Camp. Only ROS significantly decreased without any compensation (increase in PA) being made at Post-Camp in females. In conclusion, this finding, namely that ROS significantly decreased only at Post-Camp without any compensatory mechanism (increase in PA), would suggest that the training camp imposed greater loading on females than males. This consideration was supported by the atypical aspartate aminotransferase, leukocyte/neutrophil counts and C4 findings which were seen at Post-Camp only in females. Therefore, regularly examining neutrophil functions such as ROS and PA might be a good preventative measure against overtraining in athletes participating in training camps.

Effects of a bout of traditional and original sumo training on neutrophil immune function in amateur university sumo wrestlers.

In order to examine in detail the influence on the neutrophil immune function in sumo wrestlers of performing traditional and original training we examined changes in the neutrophil immune function in 17 male amateur university sumo wrestlers (aged 20.2 +/- 1.5 years), before ('Pre') and after the training ('Post') for 2.5 h under fasting conditions. Assays included blood leukocyte and neutrophil counts, serum concentration of immunoglobulins, complements, myogenic enzymes and neutrophil oxidative burst activity (OBA) and phagocytic activity (PA). Myogenic enzymes, neutrophil counts, the ratio of neutrophil counts:leukocyte counts significantly increased and immunoglobulins and complements decreased in Post compared with Pre. There was a positive correlation between the change of neutrophil counts before and after the training and the change of creatine kinase (r = 0.667, p < 0.01). The Post OBA significantly increased and PA significantly decreased compared with Pre. It was concluded that sumo training causes muscular damage and an increase in the neutrophil count as a response. In this time, although OBA increased, PA decreased after training. Compensation between PA and reactive oxygen species production may exist to maintain the overall integrity of the neutrophil immune function.

The decreasing burden of gastric cancer in Japan.

Gastric cancer in Japan, previously the top killer cancer, has recently shown decreased incidence and mortality rates. Epidemiological studies have demonstrated that environmental factors are closely associated with stomach oncogenesis, as evident from the geographical differences seen throughout Japan in both incidence and mortality. Moreover, Japanese immigrant populations gradually exhibit the lower incidence and mortality rates of gastric cancer in their chosen country. Likewise, younger generations in Japan have lower mortality rates than older generations at the same age, which may be accounted by the dramatic lifestyle changes in Japan after World War II. In addition to exploring and learning from the impact of these environmental factors, deliberate strategies to further lower the incidence and mortality rates of gastric cancer must include aggressive eradication programs for Helicobacter pylori and dietary education in both school curricula and for the general adult population to lower the intake of causative agents such as salt and increase the intake of beneficial agents such as fruits, vegetables and seaweeds. The dietary education should be coupled with better motivation for the general population to undergo regular screening with improved techniques. In the future, changes in these environmental factors and progresses in the diagnosis of and therapeutic strategies for gastric cancer will lead to further decrease in the incidence and mortality rates of this disease in Japan.

Change in the capability of reactive oxygen species production by neutrophils following weight reduction in female judoists.

OBJECTIVE: Athletes undergoing weight reduction are recognised as being more prone to infection. Few studies exist for athletes on the weight reduction-mediated changes in neutrophil function and related activities such as reactive oxygen species (ROS) production capability, phagocytic activity (PA) and serum opsonic activity (SOA). METHODS: 16 Japanese female university judoists were examined in the early morning of the first day (pre-values) and the last day (post-values) of a 20-day pre-competition training period. Of the 16 subjects, 8 needed to reduce weight (WR group) and the other 8 did not (control group). The parameters assessed were the neutrophil count, serum immunoglobulins and complements, myogenic enzymes, ROS production capability, PA and SOA. RESULTS: Comparing the post-values with the pre-values, ROS production significantly increased in both groups (p<0.01 for both). PA significantly decreased in the WR group (p<0.05); it also decreased in the control group but the decrease was not significant. SOA significantly increased in the control group (p<0.05), but showed no significant change in the WR group. CONCLUSIONS: The changes in the WR group were probably a direct consequence of the weight-reduction regimen coupled with the exercise regimen, suggesting that neutrophil parameters (ROS production, PA and SOA) had tended to deviate from their typical compensatory changes to maintain immune system homoeostasis.