Characteristic pattern of human prostatic growth with age

Aim: To study the characteristic pattern of the age-related growth of the human prostate gland. Methods: The volume (weight) of the prostate in 1,601 males, aged from newborn to 92 years, was determined by Bultrasonography. Results: Prostatic volume determination by B-ultrasonography in 1601 males (1301 normal subjects and 300 BPH patients) pointed out that the age-stratified growth of human prostate could be categorized into 4 life stages: (1) the first slow growing phase (from newborn to 9 years): the prostate grows slowly at a rate of 0.14g per year; (2) the first rapid growing phase (from 10 to 30 years): the prostate grows at a rate of 0.84 g per year; (3) the second slow growing phase (from 30 to 50 years), the prostate grows at a rate of 0.21 g per year; (4) the second rapid growing phase (from 50 to 90 years): the prostate grows at one of the following rates: in one group the growth rate is of 0.50 g per year and in the other 1.20 g per year, leading to benign prostatic hyperplasia (BPH). Conclusion: The volumes of the prostate are different in different age groups and it grows with age at different rates in four life phases. The prostate growth in phases can be expressed by the following equation: Y=19.36+1.36X'-0.58X'2+0.33X'3, where Y=prostate volume, X=age (up to 70 years), X'=(X-35.5)/10. (Asian JAndrol 2002 Dec; 4: 269-271)

Diabetes and cancer: Associations, mechanisms, and implications for medical practice

Both diabetes mellitus and cancer are prevalent diseases worldwide. It is evident that there is a substantial increase in cancer incidence in diabetic patients. Epidemiologic studies have indicated that diabetic patients are at significantly higher risk of common cancers including pancreatic, liver, breast, colorectal, urinary tract, gastric and female reproductive cancers. Mortality due to cancer is moderately increased among patients with diabetes compared with those without. There is increasing evidence that some cancers are associated with diabetes, but the underlying mechanisms of this potential association have not been fully elucidated. Insulin is a potent growth factor that promotes cell proliferation and carcinogenesis directly and/or through insulin-like growth factor 1(IGF-1). Hyperinsulinemia leads to an increase in the bioactivity of IGF-1 by inhibiting IGF binding protein-1. Hyperglycemia serves as a subordinate plausible explanation of carcinogenesis. High glucose may exert direct and indirect effects upon cancer cells to promote proliferation. Also chronic inflammation is considered as a hallmark of carcinogenesis. The multiple drugs involved in the treatment of diabetes seem to modify the risk of cancer. Screening to detect cancer at an early stage and appropriate treatment of diabetic patients with cancer are important to improve their prognosis. This paper summarizes the associations between diabetes and common cancers, interprets possible mechanisms involved, and addresses implications for medical practice.

Direct numerical simulation of turbulent boundary layer over an anisotropic compliant wall

Direct numerical simulation of a spatially developing turbulent boundary layer over a compliant wall with anisotropic wall material properties is performed. The Reynolds number varies from 300 to approximately 860 along the streamwise direction, based on the external flow velocity and the momentum thickness. Eight typical cases are selected for numerical investigation under the guidance of the monoharmonic analysis. The instantaneous flow fields exhibit the traveling wavy motion of the compliant wall, and the frequency-wavenumber power spectrum of wall pressure fluctuation is computed to quantify the mutual influence of the wall compliance and the turbulent flow at different wave numbers. It is shown that the Reynolds shear stress and the pressure fluctuation are generally enhanced by the wall compliance with the parameters considered in the present study. A dynamical decomposition of the skin-friction coefficient is derived, and a new term (CW) appears due to the wall-induced Reynolds shear stress. The influence of the anisotropic compliant wall motion on the turbulent boundary layer through the wall-induced negative Reynolds shear stress is discussed. To elucidate the underlying mechanism, the budget analysis of the Reynolds stresses transportation is further carried out. The impact of the wall compliance on the turbulent flow is disclosed by examining the variations of the diffusion and velocity-pressure correlation terms. It is shown that increase of the Reynolds stresses inside the flow domain is caused by enhancement of the velocity-pressure correlation term, possibly through the long-range influence of the wall compliance on the pressure field, rather than diffusion of the wall-induced Reynolds shear stress into the fluid flow.

Multi-scale analysis of subgrid stress and energy dissipation in turbulent channel flow

In present study, the subgrid scale （SGS） stress and dissipation for multiscale formulation of large eddy simulation are analyzed using the data of turbulent channel flow at Ret = 180 obtained by direct numerical simulation. It is found that the small scale SGS stress is much smaller than the large scale SGS stress for all the stress components. The dominant contributor to large scale SGS stress is the cross stress between small scale and subgrid scale motions, while the cross stress between large scale and subgrid scale motions make major contributions to small scale SGS stress. The energy transfer from resolved large scales to subgrid scales is mainly caused by SGS Reynolds stress, while that between resolved small scales and subgrid scales are mainly due to the cross stress. The multiscale formulation of SGS models are evaluated a priori, and it is found that the small- small model is superior to other variants in terms of SGS dissipation.

Lack of association between lysyl oxidase-like 1 polymorphisms and primary open angle glaucoma: a meta-analysis

AIM:To study the associations between lysyl oxidaselike 1(LOXL1)polymorphisms and primary open angle glaucoma(POAG)remain inconsistent.In this study,we have performed a meta-analysis to investigate the association of LOXL1 polymorphisms with POAG risk.METHODS:Published literature from PubMed and other databases were retrieved.All studies evaluating the association between LOXL1 polymorphisms(rs2165241,rs1048661,rs3825942)and POAG risk were included.Pooled odds ratio(OR)and 95%confidence interval(CI)were calculated using random-or fixed-effects model.RESULTS:Twelve studies were identified as eligible articles,with thirteen(2098 cases and 16 473 controls),thirteen(1795 cases and 2916 controls)and sixteen population cohorts(2456 cases and 2846 controls)for the association of rs2165241,rs1048661 and rs3825942with POAG risk respectively.Overall analyses showed noassociation between each LOXL1 polymorphism and POAG risk,and the negative associations were remained when the subjects were stratified as Caucasian and Asian.The heterozygote of rs2165241 was associated with reduced POAG risk in hospital-based populations(TC vs CC:OR,0.79,95%CI:0.63-0.99),and rs1048661was associated with increased POAG risk in hospitalbased populations in a dominant model(TT vs CC+CT:OR,1.23,95%CI:1.01-1.50);however,these associations were not found in population-based subjects.CONCLUSION:This meta-analysis suggests that LOXL1 polymorphisms are not associated with POAG risk.Given the limited sample size,the associations of LOXL1 polymorphisms with POAG risk in hospital-based populations await further investigation.