Prevalence estimates for primary brain tumors in China: a multi-center cross-sectional study / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Although the first leading cause of death in China was malignant neoplasms (mortality, 374.1 per 100,000 person-years), the full impact of primary brain tumors (PBT) on the healthcare system is not completely described because there are a few well documented reports about the epidemiologic features of brain tumors. This study aimed to report a comprehensive assessment on the prevalence of PBT.</p><p><b>METHODS</b>A multicenter cross-sectional study on brain tumor (MCSBT) in China was initiated in five regional centers: Daqing (northeast), Puyang (north of China), Shiyan (center of China), Ma'anshan (center of China) and Shanghai (southeast). Prevalence rate was calculated by counting the number of people living with a PBT between October 1, 2005 and September 30, 2006 and dividing by the total population of the five communities at January 1, 2006. Estimates of prevalence were expressed as percentages and grouped according to gender and to age in fifteen-year categories. Within these strata, the rates were estimated with 95% confidence intervals (CI) using the accurate calculation of CI for Poisson distribution. A chi-square test was used to compare the various frequencies with α < 0.05. Age-standardized prevalence with the direct method was calculated with the ten-year age-specific prevalence and the age distribution of the Chinese population in 2010, obtained from World population prospects: the 2008 revision.</p><p><b>RESULTS</b>We estimated that the overall prevalence of PBT was 24.56 per 100,000 (95%CI, 14.85 to 34.27), and the overall prevalence of PBT in female population (30.57 per 100,000 and its 95%CI ranged from 19.73 to 41.41) was higher than that in male population (18.84 per 100,000 and its 95%CI ranged from 10.33 to 27.35). However, the discrepancy between genders was not statistically significant because the 95%CI overlapped. Of 272 cases of newly diagnosed PBT, the proportion of histological subtypes by age groups, gender was statistically different (χ(2) = 52.6510, P < 0.0001). More than half of all reported tumors (52.57%) were either gliomas or meningiomas. For the youngest (aged from 0 - 19) strata of the population, glioma appeared to occur more than other subtypes, accounting for 55.56% of all of cases. The majority of brain tumors presented in those aged from 20 to 59 years was pituitary adenomas (45.12%) and gliomas (31.10%). Opposed to brain tumors in adults and teenage, gliomas only accounted for 22.22%. Meanwhile, the median ages at diagnosis of the patients with PBT were similar between males and females except for pituitary adenomas (male: 59 years old; female: 45 years old).</p><p><b>CONCLUSIONS</b>Age standardized prevalence of PBT is 22.52 per 100,000 (95%CI, 13.22 to 31.82) for all populations, 17.64 per 100,000 (95%CI, 9.41 to 25.87) for men, and 27.94 per 100,000 (95%CI, 17.58 to 38.30) for women. Age standardization to China's 2010 population yielded an estimated population of 304 954 cases with PBT. Our prevalence estimates provide a conservative basis on which to plan health care services and to develop programmatic strategies for surviving. In the future, it would be helpful to have long-term observed survival rates that would make the assumptions and the resulting imprecision in the current estimates unnecessary.</p>

Influence of electromagnetic irradiation on P450scc mRNA expression in rat testis tissues and protective effect of the shield / 中华男科学杂志

<p><b>OBJECTIVE</b>To study the influence of electromagnetic irradiation on cytochrome P450 cholesterol side chain lyase (P450scc) in adult rat testis tissues and to assess the protective effect of the copper shield.</p><p><b>METHODS</b>Healthy male Wistar rats were randomized into a control group, an electromagnetic irradiation group and a wholly shielded group (with the copper shielding net). The electromagnetic irradiation group and the shielded group were set for 4 phases of 3, 6, 24 and 72 hours after irradiation, 15 rats for each phrase. The testosterone contents in the serum of the irradiated rats at 3, 6, 24 and 72 hours and in that of the controls were measured by radioimmunoassay(RIA), and so was the level of the P450scc mRNA in the testis tissues by semi-quantitative RT-PCR. And the effect of the copper shielding net on testosterone and P450scc mRNA was observed.</p><p><b>RESULTS</b>The contents of testosterone and the P450scc mRNA level in the irradiated group were significantly lower than in the control rats, decreased by 83.9% and 56.9% at 3 hours (P < 0.01), 54.8% and 27.3% at 6 hours (P < 0.01), restored to normal at 24 hours, but again reduced by 60.1% and 56.1% respectively (P < 0.01). While in the shielded group, no significant change was observed either in the testosterone of the serum or in the P450scc mRNA expression in the testis tissues.</p><p><b>CONCLUSION</b>Electromagnetic irradiation may affect the transcription of P450scc in adult rat Leydig cells and thereby decrease the testosterone synthesis. Whole-body shielding with the copper net may achieve satisfactory effect.</p>