The mdr 1-type P-glycoprotein can confer multidrug resistance to tumor cells by actively pumping a wide variety of drugs from the cells. To counteract this drug resistance, P-glycoprotein-blocking agents are currently administered to patient during chemotherapy. However, this may also affect the normal physiological functions of the mdr 1-type P-glycoprotein. The P-gp is a transmembrane efflux transporter found on the luminal side of the capillary cells that comprise the blood-brain barrier. Recent insights recognize P-glycoprotein, as an important element of the blood-brain barrier (BBB), play an important role for mdr 1a P-glycoprotein in the blood-brain barrier. Studies in mice, which lack P-gp in the BBB 〔mdr1a (-/-) mice〕, have contributed significantly to these insights. In addition, the potential of new therapeutic approaches in the near future as well as their limitations will be clearified.

The circle of Willis is the major cerebral collateral circulation.Its anatomical variation is in populations higher.The previous studies showed that anatomical variation in circle of Willis was an independent risk factor for cerebral ischemia.This article reviews the relationship between the various anatomical variation types of the circle of Willis and cerebral ischemia.

Aim To study the effect of cyclosporin A and tetrand ri ne on P-glycoprotein (P-gp)of bovine brain capillary endothelial cell. M ethods The fluorescent dye, rhodamine-123 (Rh-123) was used to evaluate t he functional activity of the P-glycoprotein (P-gp) efflux transport system in primary cultured bovine brain capillary endothelial cell (BCEC) monolayer. Results Rhodamine-123 accumulation was increased significantly in monola yer treated with the P-gp modifying agent, cyclosporin A and tetrandrine. Conclusion The observation suggests that this Rh-123 method is sens itive, stable to evaluate the function of P-gp of blood-brain barrier (BBB). R h-123 accumulation is also increased by tetrandrine in dose-dependent manner.

AIM: To investigate the role and signal mechanism of PPAR-α in the pathogenesis of cardiac hypertrophy. METHODS: Small interfering RNA (siRNA) was applied to efficiently silence the gene expression of PPAR-α in cardiac myocytes. [~3H] leucine incorporation assay was performed to measure protein synthesis. Reverse transcription-polymerase chain reaction (RT-PCR) was used to analyze the mRNA level of atrial natriuretic factor (ANF) and PPAR-α. Western blotting analysis was performed to investigate the levels of phosphorylation of protein kinase B (PKB/Akt) and glycogen synthase kinase 3β (GSK3β). Immunofluorescence analysis was used to examine the cellular localization of NFATc4. RESULTS: (1)RSS304168 was the most efficient stealth RNAi duplex to specifically inhibit PPAR-α expression. (2)RSS304168 significantly potentiated the ET-1-induced cardiomyocyte hypertrophy and enhanced ET-1-induced protein synthesis and ANF mRNA expression in cardiomyocytes. Moreover, RSS304168 completely reversed the inhibitory effects of fenofibrate on ET-1-induced protein synthesis and ANF mRNA expression. (3)RSS304168 enhanced ET-1-induced phosphorylation of Akt at Ser473 and GSK3β at Ser9. The effects of ET-1 or ET-1 combined with RSS304168 on phosphorylation of Akt/GSK3β were completely blocked by LY294002, a PI3K specific inhibitor. Fenofibrate markedly inhibited ET-1-induced phosphorylation of Akt/GSK3β while RSS304168 abolished these effects of fenofibrate. (4)Fenofibrate prevented the nuclear translocation of NFATc4 induced by ET-1 while RSS304168 abolished this effect of fenofibrate. CONCLUSION: Activation of PPAR-α inhibits ET-1-induced cardiomyocyte hypertrophy through blocking Akt/GSK3β-NFATc4 signaling pathways.

BACKGROUND:Our previous studies confirmed that NGF-PEG-PLGA-NPs has good sustained release effect and biological activity in vitro, and can induce the differentiation of PC12 cel s into neuron-like cel s.
OBJECTIVE:To investigate the feasibility of neuronal differentiation of neural stem cel s from septal area of fetal brain induced by NGF-PEG-PLGA-NPs and its influence on PI3K/Akt signaling pathway.
METHODS:According to optimization prescription, NGF-PEG-PLGA-NPs were prepared by multiple emulsion solvent diffusion method. Neural stem cel s were induced to neuronal differentiation in six groups, including control group, NGF group, NGF-PEG-PLGA-NPs group, LY294002 group, LY294002+NGF group and LY294002+NGF-PEG-PLGA-NPs group. Neurons were identified by immunofluorescence, while phosphorylation levels of Akt in PI3K/Akt signaling pathway were detected by western blotting.
RESULTS AND CONCLUSION:The proportions ofβ-Tubulin III-positive neurons in control group, NGF group, NGF-PEG-PLGA-NPs group, LY294002 group, LY294002+NGF group and LY294002+NGF-PEG-PLGA-NPs group were (22.80±2.58)%, (35.80±3.98)%, (35.40±5.77)%, (26.60±3.87)%, (21.20±2.59)%and (25.80±7.22)%, respectively. There were no statistical differences in neuronal differentiation between NGF group and NGF-PEG-PLGA-NPs group (P>0.05), but the ratios of neural differentiation in the two groups were both higher than that in the other four groups (P<0.05). Western blotting results revealed that there were no statistical differences in Akt phosphorylation levels between NGF group and NGF-PEG-PLGA-NPs group (P>0.05), but the phosphorylation levels of Akt were both higher than other four groups (P<0.05). There were also no significant differences between LY294002+NGF and LY294002+NGF-PEG-PLGA-NPs groups and control group (P>0.05), but the phosphorylation levels of Akt were higher than LY294002 group (P<0.05). Results suggest that NGF-PEG-PLGA-NPs promoted neural differentiation of neural stem cel s. The role might be related to increasing phosphorylation levels of Akt in PI3K/Akt signaling pathway.

ObjectiveTo explore the relationship between glial growth factor (GGF), nerve growth factor (NGF) and growth characteristics of prolactinoma (PRL) and to evaluate pre and postoperative growth of PRL. MethodsImmunohistochemistry was used to analyze expression of GGF and NGF in 86 cases of PRL and to analyze the relationship between expression of GGF, NGF and PRL level, invasion, stroke, microvessel density. Cells were cultured with GGF and NGF to observe cell growth, cell cycle and angiogenesis. The relationship between proliferation, growth rate and GGF, NGF was evaluated by rank correlation and Chi-square test. Results GGF expression was significantly higher in invasive, stroke and recurrent pituitary adenomas ( P ＜ 0.05 ).Microvessel density increased significantly ( P ＜ 0.01 ). NGF expression was significantly lower in invasive, apoplexy and recurrent adenomas ( P ＜ 0. 05 ). Microvessel density decreased dramatically with NGF interruption ( P ＜ 0.05 ). GGF showed a positive correlation with growth rate of PRL. NGF showed a negative correlation with invasion and stroke. ConclusionsGGF is one of the factors facilitating growth and invasion of PRL while NGF can partly restrain proliferation of PRL cells. Expression of GGF and NGF indirectly reflects proliferation activity of PRL and can be used as markers to evaluate invasion, recurrence, treatment response and prognosis of PRL.

Objective To investigate the protective effect of polymyxin B (PMB) to the liver graft after liver transplantation and the underlying mechanism in rats.Methods Male SD rats were selected as the donors and recipients.Non-artery whole liver transplantation model was established in rats according to Kamada's two-cuff method.The rats were divided into two groups by the way of random number table method:control group (normal saline,0.5 ml) and PMB group (PMB,1 mg/ml,0.4 mg/kg+ normal saline 0.5 ml).The levels of portal vein plasma endtotoxin (EU/ml)were determined by endotoxin-analyzing machine of BET-24A. ALT,BUN,and TNF-α,IL-6 in serum were measured by using machine of Automatic Analyzer and ELISA,respectively.The CD14,TLR4,NFκB and AP-1 in the grafts were measured by RT-PCR and Western blotting,and pathological changes were observed. Results PMB decreased the levels of portal vein plasma endotoxin 1 h after reperfusion in PMB group as compared with control group (P＜0.05),and the levels of portal vein plasma endotoxin returned to the normal levels 6 h after reperfusion in both two groups (P＞0.05).After operation,the levels of ALT,TNFα and IL-6 in serum were significantly reduced (P＜0.05),the expression of CD14 and TLR4 mRNA in the grafts was significantly decreased (P＜0.05),the expression of Hsp60 protein and mRNA,and NF-κB and AP1 proteins in the grafts were reduced (P＜0.05),and the pathological damage to the grafts was significantly alleviated in PMB group as compared with control group.Conclusion PMB reduced the levels of portal vein plasma endotoxin after reperfusion in liver transplantation in rats.PMB improved liver function,reduced the injury of inflammatory response,decreased the levels of endotoxin signal pathway markers and alleviated the pathological damage to the grafts.

Objective To study the relationship between hepatic arterial buffer response (HABR),recovery of liver function,early biliary complications and small-for-size syndrome (SFSS).Methods Early hepatic hemodynamic parameters (including hepatic arterial flow (HAF),portal venous flow (PVF) were measured using duplex Doppler sonography in 34 patients who received living donor liver transplantation (preoperatively n＝26,intraoperatively n=26) and on postoperative days 1,2,3,and 7.Alanine aminotransferase (ALT),aspartate aminotransferase (AST) and total bilirubin (TBIL) level were measured preoperatively and on postoperative days 1,2,3,7,14,21,and 28.If TBIL level was elevated,we used B ultrasonography or CT and even ERCP to diagnose early biliary complications.The days taken for AST,AI T and TBIL to recover and the number of patients with early (＜60 days) biliary complications (bile leakage or bile stricture) and with small-for-size syndrome (SFSS) were recorded.Results Passive hepatic artery buffer response (HABR) was present in 11 patients early after living donor liver transplantation (group 1) and it disappeared in 23 patients (group 2).The recovery in days taken for normalization of AST (10.6± 8.8),AIT (11.6±9.0) and TBlL (average of 29) in group 1 were shorter than in group 2.However,the differences did not reach statistics difference (P＞0.05).The overall incidences of early biliary complications and small-for-size syndrome (SFSS) in group 1 were significantly lower than in group 2 (P=0.04).The survival rate in group 1 was 82 ％,compared with 74 ％ in group 2.Conclusions Passive hepatic arterial buffer response (HABR) disappeared in some patients early after living donor liver transplantation.There were high incidences of early biliary complications and small-for-size syndrome (SFSS) in these patients.Measurcment of hepatic buffer response in the early stage after living donor liver tranaplanta tion is valuable for predition of early biliary complications and small-for-size syndrome (SFSS),thus helping to prevent failure in transplantation.

Objective To investigate and compare the dynamic changes of plasma endotoxin and CD14/TLR4 levels in the portal vein following partial liver transplantation in rats. Methods 100 %(group Ⅰ), 50 % (group Ⅱ) and 30 % (group Ⅲ) orthotopic liver transplantation models in the SD rats→SD rats were established in vivo according to "Kamada two-cuff method". Based on the principle of dynamic turbidity law, the plasma endotoxin (EU/ml) levels were determined at the postoperative time points of 1, 3, 6, 12, 24 h in recipients. The mRNA expression levels of CD14 and TLR4 in liver grafts were detected by using real-time RT-PCR. Results Under the condition of no significant difference in surgical factors, the plasma endotoxin levels in the portal vein of groups Ⅱ and Ⅲ were higher than in group Ⅰ , and reached the peak at the first h postoperation. The endotoxin levels in group Ⅱ were lower than in group Ⅲ. The endotoxin levels in sham-operation group were the highest. The mRNA expression levels of CD14 and TLR4 in groups Ⅰ, Ⅱ and Ⅲ were significantly increased as compared with sham-operation group (P＜0. 01). Conclusion There exists portal vein plasma endotoxima in 100 %, 50 % and 30 % orthotopic liver transplantation in the rats. The smaller the graft volume, the higher and longer plasma endotoxin in portal vein, so is the relative quantification of the TLR4 and CD14 mRNA in liver grafts.

Objective To investigate the cause and related risk factors of an outbreak caused by Brucellosis. Methods Epidemiological investigation and laboratory test were carried out among occupationally invloved population including sheep slaughters and sellers in the village. Results 18 people were serology positive among the 129 occupationally involved persons under survey. Seven of them were confirmed cases,11 were latent infection,to make the overall attack rate as 14%. 90%of the sheep were from high-risk areas of Brucella. Among the occupationally involved persons,89%of them never wore face masks,84%never wear overalls and 70%never wear gloves. Factors as:work but wearing no gloves(RR=7.4,95%CI:1.1-53.0),with hand wound(RR=3.4,95%CI:1.1-11.0) could increase the risk of Brucella infection. Conclusion The cause of this outbreak was due to the plentiful influx of unchecked sheep from the northern part of China and the employees in the process of sheep slaughtering or trading were lack of effective prevention programs.