Radix Astragali lowers kidney oxidative stress in diabetic rats treated with insulin

Fluctuations in glucose levels in diabetic patients can result in oxidative stress, resulting in an increased risk for diabetic complications. We investigated whether antioxidation would protect the kidney from oxidative stress in diabetic rats treated with insulin and provide evidence for the efficacy of antioxidant treatment in diabetes management. Diabetes was induced by injection of Streptozotocin intraperitoneally in male Wistar rats. Diabetic rats received either insulin, both insulin and Radix Astragali (RA), RA, or no treatment. The levels of malondialdehyde (MDA), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) and activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) in kidney were determined. The changes of blood glucose levels and body weight were monitored. The levels of serum creatinine (Scr) were determined. The expression of PKCα was determined by western blot. NF-κB activation in kidney was assessed using EMSA. Compared to diabetic rats treated with insulin alone, the diabetic rats treated with combination of insulin and RA showed: (1) significantly lower levels of MDA, IL-6, TNF-α, and Scr (p < 0.05); (2) significantly higher SOD and GSH-Px activities (p < 0.05); (3) significantly lower NF-κB activation and lower expression levels of PKCα (p < 0.05); (4) significantly smaller kidney-to-body weight ratio (p < 0.05). RA is an effective agent in lowering oxidative stress in diabetic rats treated with insulin. Antioxidation is beneficial in reducing the risk of kidney damage due to oxidative stress in diabetic patients.

Stability of lyophilized human platelets loaded with small molecule carbohydrates

Long-term preservation of platelets is a great challenge for blood transfusion centers, due to the required narrow storage temperature arange (22 ± 2 degree C). Short shelf life and potential bacterial growth often lead to the shortage of high-quality platelets. Freeze-dried preservation is thus believed to be a potential solution for long-term platelet storage without losing the hemostasis function. Here we report a new platelet preservation method, which uses small molecule carbohydrates to extend storage time and to maintain platelet function. The activities of lyophilized platelets that were stabilized with small molecule carbohydrate (e.g., cell viability, mean platelet volume, activation characteristics, and aggregation kinetics) were maintained after storage of 30, 60, and 90 days at room temperature, 4 degree C, and -20 degree C. The recovery of freeze-dried platelets was 87 percent in comparison to fresh platelets. The mean platelet volume of rehydrated platelets increased (from 6.8 fl to 8.0 fl). About 40 percent of rehydrated platelets was in the early-activated stage (PCA-1 positive) and 30 percent was in the terminal-activated stage (CD62P positive). The cell viability was about 60 percent as measured with CMFDA vital probes. The aggregation rate of rehydrated platelets after 90-day storage was similar to fresh platelets stored at 22 degree C ± 2 degree C.

Changes of phosphatidylserine distribution in human red blood cells during the process of loading sugars

The plasma membrane of red blood cells permits sugars to be loaded into the cytoplasm simply by incubation in a suitable buffer solution containing the sugar. This may provide some hope for the freeze-drying of human red blood cells. However, the effect of the loading process on red blood cells has not been fully investigated. The exposure of phosphatidylserine (PS) on the surface of the cell can be recognized by macrophages and result in shortened circulation in vivo. This study evaluates the effects of the concentration, the incubation time, and the temperature of exposure of human red blood cells to extracellular trehalose or glucose. Exposure of PS was demonstrated by annexin V labeling. It was shown that the efficiency of loading of glucose was significantly greater than that of trehalose. The loading efficiency of both sugars increased with increase in extracellular sugar concentration, prolongation of incubation time, and increase of incubation temperature. The percentages of cells with exposed PS and of damaged cells were dependent on the extracellular sugar concentration, the incubation time, and the temperature. With an extracellular glucose concentration of 0.8M, the percentage of cells with exposed PS was more than 80% and significantly higher than that of red blood cells loaded with trehalose (approximate 20%, P<0.01). As the incubation time was prolonged, the percentage of PS exposure and of damaged cells also increased. After incubation for 5h, the percentage of red cells with exposed PS following loading with glucose was more than 80% and significantly higher than that of cells loaded with trehalose (40%, P<0.01). In addition, the incubation temperature had a major effect on PS exposure. The percentage of cells with PS exposure and the proportion of damaged cells increased with increase of incubation temperature. At 37 degrees C, the percentage of cells with exposed PS and of damaged cells after loading with glucose was more than 80% and significantly higher than that of cells loaded with trehalose (P<0.01). However, when the temperature was below 25 degrees C, the percentage of cells with exposed PS and of damaged cells after loading with glucose or trehalose were both less than 10%. In conclusion, the loading efficiency for glucose was higher than that for trehalose, but the lesser effect of trehalose on exposure of PS suggests that it can maintain the asymmetrical distribution of membrane phospholipids and the intracellular trehalose can increase the osmotic tolerance of cells.

A ten-year observation on experimental infection of periodic Brugia malayi in man

This paper reports the results of 10 years of observations on the clinical manifestations, pathology and immunity to filariasis and aetiological biology of filariae in three volunteers (first author and his family members) who were inoculated experimentally with infective larvae of periodic Brugia malayi in 1981. The changes in clinical symptoms and signs were recorded systematically. Microfilariae were first detected at 41 and 46 weeks after inoculation in two subjects and remained detectable in small numbers until 8-8.5 years after infection. The microfilarial density fluctuated at 1-2 mf 120 microliters-1. Thereafter no microfilariae were detected in 12 blood sample examinations, suggesting that the adult reproductive period of periodic B. malayi could last up to 8-9 years in the human body. Eosinophilia occurred mainly before and at the initial stage of microfilaraemia. An increase in the lymphocytes was observed to some extent at 2-156 weeks after infection. Biopsy at the inoculation site 6 weeks after inoculation showed infiltration of the lymph node by inflammatory cells, mainly eosinocytes, lymphocytes and monocytes. Lymphangiectasis and lymphostasis were observed in both limbs and pelvic regions by lymphangiogram taken 11 weeks after inoculation. Antibodies against B. malayi first appeared at 2-5 weeks after infection, peaked at 12-56 weeks and thereafter declined gradually. Subjects A and C became antibody free but subject B remained positive to antibody against B. malayi 10 years after infection. E-rosette forming lymphocytes became lower than normal at 11 weeks and recovered to normal within 10 years after infection.