BACKGROUND: Among multiple signals which affect the function of melanocyte, nitrogen monoxide (NO) has been thought as an important signal molecule. Emodin hypo-acid, effective component of rhubarb, can affect proliferation of melanocyte and regulate activity of tyrosinase in cells. OBJECTIVE: To study the effect of emodin hypo-acid on expression of nitricoxide synthase (NOS) of melanocyte in skin of guinea pig and definite the effective concentrations and mechanism of melanocyte in synthesizing melanin in living skin.DESIGN: Completely randomized grouping design and controlled study.SETTING: Department of Dermatology, Affiliated Hospital of Luzhou Medical College.MATERIALS: The experiment was completed at the Infection Laboratory of Affiliated Hospital of Luzhou Medical College and Laboratory of Histology and Embryology of Luzhou Medical College from January to June 2004. A total of 24 adult healthy male guinea pigs were randomly divided into 6 groups: control group, 2, 5, 10, 20 and 40 mg/L emodin hypo-acid groups with 4 in each group.METHODS: ① Emodin hypo-acid was diluted with dimethyl-sulfoxide into 2, 5, 10, 20 and 40 mg/L, then guinea pigs in emodin hypo-acid groups were injected subcutaneously with relevant dosages of emodin hypoacid which was provided by National Institute for the Control of Pharmaceutical and Biological Products into local skins of haunch and back, and the injected volume was 1 mL. Twenty-four hours later, 1 mL emodin hypo-acid of the same concentration was injected once again into one of the places which was injected before. Skin samples were selected after 48 hours and routine paraffin section was made. Skins which were not injected with any drugs were selected from control group and emodin hypoacid groups to regard as experimental control group. ② Expression of NOS was assayed with immunohistochemical method and melanocyte was identified under high-times optic microscope to observe stain and characteristic of cytoplasm. Five sections were randomly selected from each group. Every 20 cells on each section were measured with MLAS-1000 imaging analyzer and computer processing system was used to calculate average absorbency (A) of positive immune product in melanocyte. ③ Measurement data were compared with analysis of variance, and differences among groups were compared with SNK-q.MAIN OUTCOME MEASURES: Expression of NOS in melanocyte was assayed with immunohistochemical method and results were obtained with optic microscope and imaging analyzer.RESULTS: Average A value of positive immune product in melanocyte was lower in 2, 5, 10, 20 and 40 mg/L emodin hypo-acid groups than that in experimental control group (0.126±0.118, 0.103±0.082, 0.118±0.097,0.122±0.095, 0.112±0.078, 0.196±0.066, P ＜ 0.05). There was no significant difference among emodin hypo-acid groups at various concentrations.CONCLUSION: ① Emodin hypo-acid can regulate expression of NOS in melanocyte through NO signal transduction pathway. ② Expression of NOS is not changed as the mass concentration of emodin hypo-acid varied from 2 to 40 mg/L.

Objective To develop a new method for establishing a temperature gradient field in the microchannel on a glass-polydimethylsiloxane ( PDMS ) microfluidic chip and to verify its applicability in the study of cellular thermal biological effect.Methods The establishment and control of the temperature gradient field in the microchannel were implemented by a peripheral indium tin oxide ( ITO) heater and a heating micro-wire embedded in the PDMS chip.The temperature gradient field established in the microchannel was represented by the finite element numerical analysis and temperature-dependent fluorescent dye rhodamine B.Finally, the thermal biological effect, which used cell survival rate of human prostate cancer cells T24 as an indicator, was investigated in the microchannel.Results The results of finite element numerical analysis proved that this method established a temperature gradient field along the length of the microchannel successfully.The distribution range of the temperature gradient field was controlled by the ITO heater, while the gradient of the temperature gradient field was controlled by the heating micro-wire.The measurement result of rhodamine B was identical with the result of the finite element numerical analysis.The thermal biological effect of T24 tumor cell research showed that the cell survival rate decreased with the rise of the regional temperature in the microchannel.Conclusion The method developed in this paper for establishing a temperature gradient field in the microchannel on a glass-PDMS microfluidic chip is simple and easy to implement, and it can be used for parallel study of the cellular thermal biological effect on the microfluidic chip in the future.

[Abstract] Blood transfusion is a common therapeutic measure with indispensable role in clinical medicine. However, there is a risk of transmitting diseases during blood transfusion, such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), etc. To reduce these risks and ensure blood transfusion safety, detection of disease markers in blood transfusion is particularly important. Biological sensing technology, with its advantages of high sensitivity, rapid response and portability, has broad application prospects in the detection of disease markers in blood transfusion. However, the biological sensing strategies for detection of disease markers in blood transfusion have not yet been systematically classified or fully discussed. Therefore, this paper first elucidates the common disease markers in blood transfusion and their importance. Then, it focuses on the application of biological sensors in the detection of disease markers in blood transfusion and discusses the challenges faced and the direction of future development in this field.