Changes in zinc levels and superoxide dismutase activities in the skin of acute, ultraviolet-B-irradiated mice after treatment with ginkgo biloba extract.

Acute ultraviolet-B (UV-B) irradiation is known to act as an initiator in the formation of reactive oxygen species. These oxygen products are highly reactive and they are able to cause irreversible damage to cellular components. Oxygen free radicals are normally neutralized by very efficient systems in the body. These include antioxidant enzymes like superoxide dismutase (SOD). In a healthy subject, there is a balance between free radicals and the levels of antioxidants. In some pathological conditions such as oxidative stress, the level of antioxidants is significantly reduced. The skin contains relatively high levels of zinc (Zn), an essential element known to be a cofactor in some metabolic pathways. Zinc has also been reported to have antioxidant properties. In the present study, we investigated the effect of ginkgo biloba extract (Gbe), a potent free-radical scavenger, on UV-B-irradiated skin by measuring SOD activity and Zn levels in the skin, before and after treatment. The SOD activity was decreased after UV-B exposure, in comparison with the control group (p < 0.05). After Gbe treatment, the SOD activity increased (p < 0.05) as compared with the untreated UV-B irradiated group. The Zn levels changed in the same pattern as the SOD activity values.

The effect of the sulfonylurea glyburide on nitric oxide in streptozotocin-induced diabetic rat.

1. The interaction between nitric oxide (NO) and superoxide anions has received a great deal of attention. Because NO is rapidly inactivated by superoxide anions, it has been suggested that an enhanced formation of this radical may be involved in the accelerated breakdown of NO. 2. In the present study, we administrated glyburide (glibenclamide) to Streptozotocin-induced diabetic rats and determined the effect of such treatment on serum nitrite+nitrate levels. Serum nitrite+nitrate levels were reduced in diabetic animals (P<0.001). Administration of glyburide to diabetic rats reversed the diabetes-induced changes, suggesting that glyburide may directly increase serum nitrite+nitrate levels.

Biological variation of serum lipids and lipoproteins in patients with clinically well controlled non insulin dependent diabetes mellitus.

To investigate how the visit-to-visit variation in serum lipids measurements affects the decision making concerning treatment according to the National Cholesterol Education Program (NCEP) guidelines in patients with clinically well controlled non-insulin-dependent diabetes mellitus (NIDDM) we have measured the biological variation (CVb) in serum total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) in 26 patients with NIDDM. We found the CVb as follows: TC, 5.1%; TG, 17.0%; HDL-C 4.4% and LDL-C, 8.3%. Confidence intervals (95%) were determined with total intra-individual variance values around the NCEP cut-off points to evaluate how well one, two and three lipid measurements provided reliable risk classification. A single TC measurements < 177 mg/dL or > 263 mg/dL allowed confident classification as "desirable" or "high risk" respectively. For LDL-C, one measurement was accurate only at below 106.3 mg/dL or above 183.7 mg/dL. The average of three measurements contracted these limits to < 186.7 mg/dL and > 253.3 mg/dL for TC, and < 116.3 mg/dL and > 173.7 mg/dL for LDL-C. For HDL-C also, multiple measurements improved risk assignment in a similar fashion. There were no values which allowed assignment to the "borderline high" category with one TC measurement and with one and two LDL-C measurements. The mean of three TC and three LDL-C measurements allowed assignment to the "borderline high" category, if between 213.3 and 226.7 mg/dL for TC, 143.7 and 146.3 mg/dL for LDL-C. Seven patients (26.9%) in this risk group based on the mean of two LDL-C estimates could be placed into a different category when the mean of three estimates was taken, even though the first two LDL-C test results did not differ by more than 30 mg/dL. Our results suggest that repeated lipid measurement is important especially for the "borderline-high" risk group because big variations existed in some patients, and further that TC is the most reliable quantity.