Effects of reactive oxygen species from activated leucocytes on human sperm motility, viability and morphology.

The accumulated data suggest that inflammation can increase the level of reactive oxygen species (ROS), which contribute to impaired sperm function and male infertility. Therefore, we propose that inflammation-mediated production of ROS in male and female reproductive tracts hinder sperm fertilisation. To test this hypothesis, phorbol myristate acetate (PMA) with polymorphonuclear leucocytes (PMNs) was applied to generate endogenous ROS. We evaluated the time-dependent effects of ROS on human sperm motility, viability and mitochondrial membrane potential (MMP). The results showed that after treatment with PMA and PMNs, the motility of human spermatozoa significantly decreased to 50% on Day 1 and 15% on Day 4 compared with that of the, respectively, negative controls (P = 0.012). The viability of human spermatozoa decreased on Day 4 of PMA + PMNs treatment (P = 0.028). The MMP of human spermatozoa significantly decreased from Day 2 to Day 4 in the PMA + PMN group compared with that of the controls (P = 0.019). Taken together, the 4-day cultivation approach provided an accurate evaluation of sperm quality, especially sperm motility and MMP. Our findings indicated that endogenous inflammation increased ROS levels, which might induce sperm oxidative damage. Additionally, sperm motility might be one of the earliest and most sensitive indicators of this damage.

Application of Weibull model for survival of patients with gastric cancer.

BACKGROUND: Researchers in the medical sciences prefer employing Cox model for survival analysis. In some cases, however, parametric methods can provide more accurate estimates. In this study, we used Weibull model to analyze the prognostic factors in patients with gastric cancer and compared with Cox. METHODS: We retrospectively studied 1715 patients with gastric cancer. Age at diagnosis, gender, family history, past medical history, tumor location, tumor size, eradicative degree of surgery, depth of tumor invasion, combined evisceration, pathologic stage, histologic grade and lymph node status were chosen as potential prognostic factors. Weibull and Cox model were performed with hazard rate and Akaike Information Criterion (AIC) to compare the efficiency of models. RESULTS: The results from both Weibull and Cox indicated that patients with the past history of having gastric cancer had the risk of death increased significantly followed by poorly differentiated or moderately differentiated in histologic grade. Eradicative degree of surgery, pathologic stage, depth of tumor invasion and tumor location were also identified as independent prognostic factors found significant. Age was significant only in Weibull model. CONCLUSION: From the results of multivariate analysis, the data strongly supported the Weibull can elicit more precise results as an alternative to Cox based on AIC.