血管粘弹性对法推拿作用下血管切应力的影响

目的研究血管粘弹性对脉动血流在(扌衮)法推拿作用下切应力的影响.方法建立具有局部轴向运动狭窄的粘弹性血管中脉动血流模型.设血液为牛顿流体,血管壁为线性粘弹体.在(扌衮)法推拿作用下血管受水平外力作用形成轴向运动缓变狭窄,血流遵循线化Navier-stokes方程.结果粘弹性血管在(扌衮)法作用下,距离血管入口z=31 cm处的平均切应力、最大切应力和瞬时切应力以及最大狭窄下游血管段最大切应力随着血管粘性系数和手法频率的改变而有较大变化.结论(扌衮)法推拿作用下粘弹性血管的血管切应力有显著变化,这与中医推拿的活血化淤相吻合.     

Administration of ATG according to the absolute T lymphocyte count during therapy for steroid-resistant rejection

In renal transplantation, treatment of steroid-resistant rejection (SRR) with antithymocyte globulin (ATG) has been widely reported but over-immunosuppression remains a common problem. In the first ten patients (group 1) treated for SRR with rabbit ATG, three developed serious viral infections and two deaths occurred due to CMV pneumonitis. ATG was only omitted if thrombocytopenia or neutropenia occurred. In the next 17 patients (group 2) with SRR, ATG was administered according to the absolute T lymphocyte count. T lymphocytes were measured by flow cytometric analysis of CD3-labelled lymphocytes. ATG dosage was adjusted on a daily basis to keep the absolute T lymphocyte count under 50 cells/l. Administration of ATG according to the absolute T lymphocyte count resulted in a significant reduction in the mean dose of ATG given to the group 2 patients (P<0.001). A significant decrease in the incidence of serious viral infections (P=0.04) was achieved without reducing the ability of ATG to reverse the SRR (P=0.29) or increasing the number of grafts lost at 1 year in the group 2 patients (P=0.23).     

Diabetic retinopathy and lipid abnormalities

The relationship of serum lipid levels and diabetic retinopathy has interested clinicians for several decades. Data from both a population-based study of diabetic retinopathy and a controlled, randomized trial of laser photocoagulation and aspirin treatment in diabetic retinopathy have provided further information regarding the importance of the role of serum lipids in patients with elevated serum lipid levels and diabetic retinopathy. Retinal hard exudate, which is accompanied by macular edema, is associated with elevated serum lipid levels. Although the data are observational, visual loss is likely to be associated with retinal hard exudate and serum lipid abnormalities. These relationships are evaluated in the analyses of the data from the Early Treatment Diabetic Retinopathy Study.     

Nutritional supplement use and age-related macular degeneration

Age-related macular degeneration is one of the leading causes of visual loss among people aged 65 years or older. The causes and factors associated with the progression of age-related macular degeneration are unknown presently. Basic research and epidemiologic data support the hypotheses that higher levels of antioxidant vitamins and minerals may protect the eye from the development of age-related macular degeneration. For this reason and also because of the lack of effective treatment for most cases of age-related macular degeneration, nutritional supplements with antioxidants have emerged as possible therapy for age-related macular degeneration. Nutritional supplements are not proven therapy for age-related macular degeneration. The potential beneficial effects and adverse side effects of the nutritional supplements have not yet been fully evaluated in carefully conducted clinical trials. Several randomized placebo-controlled clinical trials are presently underway. Results of these studies will provide important data to clarify the potential beneficial and adverse effects of such treatment. Until these results are available, it would be premature to make recommendations in favor of vitamin or mineral supplements.     

Prospective cohort study of antioxidant vitamin supplement use and the risk of age-related maculopathy

In a prospective cohort study, the authors examined whether self-selection for antioxidant vitamin supplement use affects the incidence of age-related maculopathy. The study population consisted of 21,120 US male physician participants in the Physicians' Health Study I who did not have a diagnosis of age-related maculopathy at baseline (1982). During an average of 12.5 person-years of follow-up, a total of 279 incident cases of age-related maculopathy with vision loss to 20/30 or worse were confirmed by medical record review. In multivariate analysis, as compared with nonusers of supplements, persons who used vitamin E supplements had a possible but nonsignificant 13% reduced risk of age-related maculopathy (relative risk = 0.87, 95 percent confidence interval (CI) 0.53-1.43), while users of multivitamins had a possible but nonsignificant 10% reduced risk (relative risk = 0.90, 95% CI 0.68-1.19). Users of vitamin C supplements had a relative risk of 1.03 (95% CI 0.71-1.50). These observational data suggest that among persons who self-select for supplemental use of antioxidant vitamin C or E or multivitamins, large reductions in the risk of age-related maculopathy are unlikely. Randomized trial data are accumulating to enable reliable detection of the existence of more plausible small-to-moderate benefits of these agents alone and in combination on age-related maculopathy.     

Calcium oxalate urolithiasis in cats

Urolithiasis has long been recognized as a cause of irritative voiding in cats. Before the late 1980s, sterile struvite was the most common urolith; today, however, 40% of feline uroliths are of calcium oxalate. This change may be partly attributable to the change to urine-acidifying, magnesium-restricted diets that were introduced to reduce the formation of struvite. However, it is possible that the diet modifications made by cat food manufacturers simply exposed a population of cats predisposed to calcium oxalate stone formation. Urolithiasis in cats appears to be diet sensitive rather than diet induced. As in humans, water is crucial in the prevention and treatment of feline stones.     

Radiation exposure: a new risk factor for idiopathic perifoveal telangiectasis

Objective

To examine the association between previous radiation exposure and idiopathic perifoveal telangiectasis (IPT).