Distribution of serum prostate-specific antigen in Chinese healthy men: a population-based study.

BACKGROUND: The morbidity and mortality of prostate cancer have been increasing rapidly in recent China. There were few studies investigating prostate-specific antigen (PSA) values ranges in the healthy Chinese population. We performed this study to determine the distribution of serum PSA in a large healthy Chinese population. METHODS: From January 2001 to May 2008, 11 150 healthy Chinese men aged 30 - 79 years came to our hospital for routine health check-up. All subjects without a previous diagnosis of prostate cancer, a history of prostate surgery, or urogenital tract infection were proposed to undergo systematic serum PSA measurement and digital rectal examination (DRE). Men with normal DRE and PSA ≤ 4.0 ng/ml and those PSA > 4.0 ng/ml or abnormal DRE but without adverse findings on prostate biopsy were included (n = 9358). Age and serum PSA concentration were recorded and correlated through Logistic regression analysis. RESULTS: The 95th percentile serum PSA concentration was 1.89 ng/ml for men aged 30 to 39 years, 2.19 ng/ml for men aged 40 to 49 years, 2.88 ng/ml for men aged 50 to 59 years, 4.42 ng/ml for men aged 60 to 69 years, and 6.52 ng/ml for men aged 70 to 79 years. The serum PSA concentration correlated with age (P < 0.0001) with an annual increase of 0.97% for men in 40 years, 1.58% for men in 50 years, 3.04% for men in 60 years, and 3.99% for men in 70 years. CONCLUSIONS: The serum PSA level correlates directly with age in Chinese men older than 40 years, not in Chinese men younger than 40 years old. Chinese men have lower PSA level compared with white men above 60 years of age, not in those under 60 years of age.

Signal peptide of potato PinII enhances the expression of Cry1Ac in transgenic tobacco.

The modified Cry1Ac was expressed in transgenic tobacco plants. To allow secretion of the Cry1Ac protein into the intercellular space, the signal peptide sequence of potato proteinase inhibitor II (pinII) was N-terminally fused to the Cry1Ac encoding region. Expression of Cry1Ac in transgenic tobacco plants was assayed with ELISA. The results showed that pinII signal peptide sequence enhanced the expression of Cry1Ac protein and led to the secretion of the Cry1Ac protein in transgenic tobacco plants. GFP gene was also fused to the signal peptide sequence and transformed to tobacco. The results of fluorescent detection showed that GFP had localized in the apoplast of transgenic plants.