Outwardly rectifying swelling-activated chloride conductance (ICl,Swell) in rabbit heart plays a critical role in cardioprotection following ischemic preconditioning (IP). But the functional characterization and molecular basis of this chloride conductance in rabbit heart ventricular myocytes is not clear. Candidate chloride channel clones (e.g. ClC-2, ClC-3, ClC-4 and ClC-5) were determined using RT-PCR and Western blot analysis. Whole cell ICl,Swell was recorded from isolated rabbit ventricular myocytes using patch clamp techniques during hypo-osmotic stress. The inhibitory effects of 4,4' isothiocyanato-2,2-disulfonic acid (DIDS), 5-nitro-2(3-phenylroylamino) benzoic acid (NPPB) and indanyloxyacetic acid 94 (IAA-94) on ICl,Swell were examined. The expected size of PCR products for ClC-2, ClC-3 and ClC-4 but not for ClC-5 was obtained. ClC-2 and ClC-3 expression was confirmed by automated fluorescent DNA sequencing. RT-PCR and Western blot showed that ClC-4 was expressed in abundance and ClC-2 was expressed at somewhat lower levels. The biological and pharmacological properties of I(Cl,Swell), including outward rectification, activation due to cell volume change, sensitivity to DIDS, IAA-94 and NPPB were identical to those known properties of ICl,Swell in exogenously expressed systems and other mammals hearts. It was concluded that ClC-3 or ClC-4 might be responsible for the outwardly rectifying part of ICl,Swell and may be the molecular targets of cardioprotection associated with ischemic preconditioning or hypo-osmotic shock.
Biophysics/methods ; Chlorides/*chemistry ; Chlorides/metabolism ; DNA Primers/chemistry ; Electrophysiology/methods ; Gene Expression Regulation ; Glycolates/pharmacology ; Heart Ventricles/*cytology ; Ischemic Preconditioning ; Muscle Cells/*cytology ; Osmosis ; Sequence Analysis, DNA

Outwardly rectifying swelling-activated chloride conductance (lCl,Swell) in rabbit heart plays a critical role in cardioprotection following ischemic preconditioning (IP). But the functional characterization and molecular basis of this chloride conductance in rabbit heart ventricular myoeytes is not clear. Candidate chloride channel clones (e.g. ClC-2, ClC-3, CIC-4 and CIC-5) were deter- mined using RT-PCR and Western blot analysis.Whole cell ICl,Swell was recorded from isolated rabbit ventricular myoeytes using patch clamp techniques during hypo-osmotic stress. The inhibitory effects of 4,4′ isothiocyanato-2,2-disulfonic acid (DIDS), 5-nitro-2(3-phenylroylamino) benzoic acid (NPPB) and indanyloxyacetic acid 94 (IAA-94) on ICl,Swell were examined. The expected size of PCR products for ClC-2, ClC-3 and ClC-4 but not for ClC-5 was obtained. ClC-2 and ClC-3 expression was con- firmed by automated fluorescent DNA sequencing. RT-PCR and Western blot showed that ClC-4 was expressed in abundance and ClC-2 was expressed at somewhat lower levels. The biological and pharmacological properties of ICl,Swell including outward rectification, activation due to cell volume change, sensitivity to DIDS, IAA-94 and NPPB were identical to those known properties of ICl,Swell in exogenously expressed systems and other mammals hearts. It was concluded that ClC-3 or ClC-4 might be responsible for the outwardly rectifying part of ICl,Swell and may be the molecular targets of cardioprotection associated with ischemic preconditioning or hypo-osmotic shock.

Objective To study the correlation between the coagulation factor Ⅶ (F Ⅶ) and progressive hemorrhage after brain contusion in mice and provide the experimental evidence for the clinical application of recombinant human FⅦa.Methods Twelve male BALB/c mice were given liposomeencapsulated FⅦsiRNA via tail vein at doses of 1,3,5 and 10 mg/kg with 3 mice per dosage.The other 3 mice received equivalent volume of normal saline as controls.Two days after the injection,mice blood sampling was used to detect FⅦ mRNA expression in liver using real-time PCR,level of plasma FⅦ using ELISA method,and activity of plasma FⅦ using chromogenic substrate assay.The optimal dose at which F Ⅶ expression was inhibited was determined.Thirty BALB/c male mice were assigned to two groups (n =15 per group) according to the random number table:FⅦ-suppressing group,mice were injected with FⅦsiRNA at the optimal dose and control group,mice were injected with same volume of negative control vector.The model of brain contusion was established in both groups.Volume of hemorrhage following brain contusion was measured at 3,24 and 72 h postinjury,and hematoma volume at 24 and 48 h postinjury.Results Liposome-encapsulated siRNA delivery down-regulated FⅦ expression in the mouse liver.Level and activity of plasma FⅦ were also reduced significantly.The optimal siRNA dose was 3 mg/kg.At 3,24 and 72 h postinjury,relative volume of brain hemorrhage in FⅦ-suppressing group was 1.46 ± 0.10,1.82 ± 0.23 and 2.28 ± 0.15 respectively,significantly higher than that in control group (1.00 ± 0.25,1.20 ± 0.31 and 1.20 ± 0.22 respectively) (P ＜ 0.05).At 24 and 48 h postinju-ry,volume of hematoma in FⅦ-suppressing group was (6.7 ± 1.5)mm3 and (9.8 ± 1.0) mm3,significantly higher than that in control group [(5.2 ± 1.2) mm3 and (5.5 ± 1.5) mm3] (P ＜0.01).Conclusions Level of FⅦ in vivo relates closely to the progressive hemorrhage of brain contusion in mice.Administration of FⅦ is effective to reduce the incidence of progressive hemorrhage.

Objective To conduct a screening survey of glycophorin (GP) variants and observe the content changes of sialic acid (SA) and total sulfhydryl (SH) groups on the erythrocyte membranes among residents in a tertian malaria hyperendemic area of Guizhou Province.Methods GP variants were detected in the erythrocyte hemolysates of 173 local residents at two villages of Libo County by SDS-PAGE on 10% to 15% gradients gel and Western immunoblotting. Their SA and total SH group contents were estimated in erythrocyte membranes by spectrophotometric methods. 114 healthy subjects in Changsha and 49 individuals at a neighbouring village of the above area showing low morbidity of malaria served as normal and endemic controls respectively.Results Three distinct types of GP variants were found among 19 propositi in this hyperendemic area. The incidence of GP variants was 7.9% (8/101) at Yaolu Village whose population was mainly composed of Yao ethnic group;while that of Buyi ethnic group at Maolan Village was higher (15.3%; 11/72).The erythrocyte membrane contents of SA in residents at both villages exhibited a very significant tendency of decline (P<0.01), whereas those of total SH groups increased prominently in residents of Yaolu Village only (P<0.05).Conclusions The frequency of GP variants in this hyperendemic area does not depend upon the severity of malarial prevalence. The evident reduction of SA contents in the residents may be related to the breaking down of the SA residues on membrane GPs by the invasion of Plasmodium vivax.

Objective To study the effect of the promoter methylation of coagulation factor Ⅶ (FⅦ) on the coagulation factor Ⅶ activity (FⅦa) in traumatic brain injury (TBI) patients,and the correlation between the promoter methylation in FⅦ and intracranial progressive hemorrhagic injury (PHI).Methods A prospective analysis was conducted on 79 patients with moderate-severe TBI admitted to emergency department from August 2010 to August 2014.The peripheral venous blood samples were collected at admission and then were delivered for measurement of FⅦa.Genomic DNA was isolated from patient blood,and the promoter methylation in FⅦ (CpG2,CpG3,CpG4,CpG5,and CpG6) were analyzed.According to the level of plasma FⅦa,the patients were divided into FⅦa ≥90％ group and FⅦa ＜ 90％ group.Based on the presence of PHI,the patients were divided into PHI group and non-PHI group.The FⅦ promoter methylation,age,gender,systolic blood pressure,Glasgow Coma Scale (GCS),length of stay and mortality between FⅦa≥90％ group and FⅦa ＜ 90％ group,PHI group and non-PHI group were compared.Results There were no significant differences in age,gender,systolic blood pressure,GCS,LOS,and mortality between FⅦa ≥90％ group and FⅦa ＜90％,PHI group and non-PHI group (P ＞ 0.05).The methylation of CpG3 in FⅦa ≥90％ group was less than that in FⅦa ＜90％ group (0.83 ±0.05 vs.0.85 ±0.03) (P＜0.05),while there were no significant differences in other CpG sites between these two groups (P ＞ 0.05).No significant differences in all of methylation levels of the CpG sites between PHI group and non-PHI group were found (P ＞0.05).Conclusions The promoter methylation of FⅦ affects plasma FⅦa concentrations,and higher methylation results in lower FⅦa.The promoter methylation of FⅦ is not associated with PHI in TBI patients.