对硫磷对大鼠红细胞膜Ca^2＋—ATP酶活性的影响

本研究发现,体外试验对硫磷可明显抑制大鼠红细胞膜Ca~(2+)-ATP酶活性(150为5.0×10~(-1)mol/L)。酶动力学分析表明此种抑制是一种混合性抑制作用。体内试验无论对硫磷5.0～25.0mg/kg一次腹腔注射还是2.5mg多次连续注射,均未见对大鼠红细胞膜Ca~(2+)-ATP酶有明显影响,但血浆Ca~(2+)含量呈现出一定的变化趋势。结果提示对硫磷对细胞内钙稳态体系可能有一定的干扰作用。     

铝盐对乳鼠神经细胞膜ATPase活力的影响

铝是公认的慢性蓄积性神经毒物,它在老年性神经退行性疾病的毒作用已受广大学者的关注[1-4],但铝(主要形式为Al3 )是如何发挥其毒性作用的,目前尚少见报道。膜毒理是从亚细胞水平阐明毒作用机制的一个重要环节,本研究采用体内实验从铝盐对乳鼠神经细胞膜酶的相互作用后活力变化,初步探讨铝神经毒作用的机制。1材料与方法1·1材料健康出生7 d的Wistar小鼠乳鼠,由兰州医学院动物中心提供(甘动准字14-0006)。1·2试剂和仪器AlCl3·6H2O(上海金山化工厂),其余试剂均为国产分析纯。高速冷冻离心机(吉林图们),721分光光度计(四川仪器厂),水浴锅…     

茛菪类药对家兔红细胞膜钠泵及钙泵活性的影响

本实验研究了茛菪类药(含东莨菪碱和阿托品)对家兔红细胞膜钠、钾三磷酸腺苷酶(Na-K-ATPasc)及钙镁三磷酸腺苷酶(Ca-Mg-ATPasc)活性的影响。结果表明:静脉注射茛菪类药2ml/kg时,Na-K-ATPase活性与实验前比较有明显增强(P<0.05),Ca-Mg-ATPase活性有下降趋势。提示茛菪类药物能改变生物膜活性,其多相药理作用很可能是通过调整生物膜的活性来发挥疗效的。     

二氧化硅对人红细胞膜ATPase和乙酰胆碱脂酶的影响

本研究探讨了二氧化硅粉尘对人红细胞膜乙酰胆碱脂酶(AChE)、Na~+、K~+-ATPase 和 Ca~(2-)-ATPase 的相互作用。结果显示二氧化硅具有吸附 AChE 的能力,对 Ca~(2+)-ATPase 活性有一定抑制,而 Na~+、K~+-ATPase 活性有所上升。提示二氧化硅在损伤细胞膜的过程中对膜酶也会产生影响。     

参麦注射液静注对红细胞膜Na~ -K~ -ATP酶的影响

为了解参脉注射液对患者红细胞(RBC)膜Na~ -K~ -ATP酶的影响,本研究随机选择级择期上腹部手术男性患者60例,根据参脉给药剂量的不同,随机分为三组,每组20例:Ⅰ组、Ⅱ组和Ⅲ组剂量分别为40,60,80 mg/kg。给药后10,20,30min时测定各组患者静脉血红细胞膜Na~ -K~ -ATP酶活性,各组患者血压、心率、氧饱和度的变化也同时被记录。结果发现:参脉注射液对RBC膜Na~ -K~ -ATP酶活性具有短暂的抑制作用,当参脉注射液输液量为80 mg/kg时对心率也存在短暂的减慢作用。     

胰岛素对人红细胞膜流动性及ATP酶活性的影响

用荧光偏振技术及孔雀绿－磷钼酸复合物比色法，研究胰岛素对人红细胞膜的流动性及ＡＴＰ酶活性的影响。结果表明，胰岛素浓度在（０－５）×１０＾－９ｍｏｌ／Ｌ时，膜的荧光偏振度及Ｎａ＾＋／Ｋ＾＋－ＡＴＰ酶活性均随胰岛素浓度的不同而变化，变化的相关性分别为ｒ＝０．９９９８，Ｐ＜０．０５和ｒ＝０．９９８９，Ｐ＜０．０５。也发现，荧光偏振度和Ｎａ＾＋／Ｋ＾＋－ＡＴＰ酶活性之间呈负相关ｒ＝－０．９９８４，Ｐ＜０．     

氟化钠对林可霉素发酵的影响

研究了在15L发酵罐中添加氟化钠对林可霉素合成的影响。结果表明,96h向培养基中添加100mg/L氟化钠,发酵液中林可霉素的效价达5795u/ml,比对照提高12.6%。进一步研究发现,氟化钠可以降低糖酵解途径中丙酮酸激酶的酶活力,使更多碳源流向磷酸戊糖途径,可为林可霉素合成提供更多前体,从而提高林可霉素产量。     

糖尿病视网膜病变与红细胞膜三磷酸腺苷酶活性的关系

糖尿病视网膜病变是糖尿病常见的并发症 ,也是眼科致盲的重要原因 ,本文通过测定糖尿病视网膜病变患者红细胞膜ATP酶的活性〔1 ,2〕及平均红细胞体积 ,并与无视网膜病变的糖尿病患者及健康志愿者进行比较 ,探讨红细胞膜 ATP酶活性改变及红细胞体积的改变与糖尿病视网膜病变的关系。1　对象与方法1.1　对象 :糖尿病视网膜病变组 :根据 WHO诊断标准的 型糖尿病视网膜病变患者 2 1例 ,男 11例 ,女 10例 ;年龄 5 4.1± 11.0岁 ;病程平均 2 2 .3± 3.5 6年。用眼底镜和 (或 )眼底荧光造影发现眼底血管病变者。糖尿病无视网膜病变组 :无任何…     

乙肝患者红细胞膜ATP酶活性的改变

对乙型肝炎患者进行了红细胞膜活性改变的探讨，现将结果报告如下。临床资料一、一般情况正常组共30例，男20例，女10例，年龄ZO～31岁。既往无肝病史，HBSAg（－）。乙型肝炎患者组共91例，男62例，女29例，年龄15～65岁，其中急性肝炎29例，慢性肝炎23例，肝硬化20例，肝癌19例。二、方法红细胞膜制备按文献报告进行，制得的膜样品登七OC待测。红细胞膜Na”、K”－ATP酶活性测定参照Reinila方法。红细胞膜Ca“’、Mg”‘－ATP酶活性测定按文献进行。红细胞膜蛋白含量测定采用Lowry法。三、结果l．红细胞膜、Na“、K”－ATP酶和…     

自体血液回收技术对红细胞膜ATP酶的影响

目的 探讨血液回收技术对红细胞膜Na^＋-K^＋-ATP酶和Ca^2＋-Mg^2＋-ATP酶活性的影响。方法 将24例患者麻醉前静脉血、术野回收原血及回收红细胞血液标本采用沈茂星法测定红细胞膜Na^＋-K^＋-ATP酶和Ca^2＋-Mg^2＋-ATP酶活性,并予统计分析。结果 经血液回收技术处理后的红细胞膜Na^＋-K^＋-ATP酶和Ca^2＋-Mg^2＋-ATP酶活性与术野回收血值比较均有显著降低（P〈0．05）。结论 自体血液回收技术能使红细胞膜Na^＋-K^＋-ATP酶和Ca^2＋-Mg^2＋-ATP酶活性明显降低。     

普伐他汀调节血脂及对血小板、红细胞膜脂肪酸成份影响的研究

目的　观察普伐他汀 (P)调脂疗效及对血小板、红细胞膜必需脂肪酸成份及多不饱和脂肪酸 (PUFA)平衡的影响。方法　对 30例原发性高脂血症者应用P 12周。治疗前后分别测定血脂、血小板及红细胞膜花生四烯酸 (AA)、廿碳五烯酸 (EPA)、廿二碳六烯酸 (DHA)。结果　治疗后血清胆固醇 (TC)、甘油三酯 (TG)、低密度脂蛋白 (LDL C)、载脂蛋白B10 0 (ApoB10 0 )明显降低 (P <0 0 5～ 0 0 0 1) ;血小板、红细胞膜AA/EPA、AA/DHA比值亦明显降低 (P <0 0 5～ 0 0 1) ,且与TG、TC、LDL C降低均呈显著正相关 (P <0 0 0 1)。结论　P除有效调脂外 ,还能影响血小板、红细胞膜脂肪酸成份及其比率 ,对防治动脉粥样硬化有重要意义     

Effects of taurine on the ATPase activity in the human erythrocyte membrane.

Effects of taurine on the total ATPase activity inhibited by ouabain were investigated in the human erythrocyte membrane. The enzyme activity was not activated by taurine in the absence of calcium, but was significantly activated by taurine (15-60 mM) in the presence of calcium (5 mM) by which the enzyme is inhibited. Since taurine does not form a chelate complex with calcium ion, this activation may be due to an action of taurine in the presence of calcium through competition with these ions on the membrane.     

Inhibition of ATPase activity in human red cell membranes by tetracaine.

This study describes the inhibition by tetracaine of two transport-related enzymes in human red cell membranes: NaK-ATPase and Ca-ATPase. Tetracaine (2.5 mM) inhibited both enzymes between pH 7.0 and 7.8; the degree of inhibition increased as the pH increased. Inhibition of NaK-ATPase increased sharply between pH 7.4 and 7.8, whereas inhibition of Ca-ATPase increased gradually. Concentration-effect studies were conducted at tetracaine concentrations between 0.25 and 2.5 mM at pH 7.8. NaK-ATPase was significantly inhibited by 1.0 mM tetracaine and inhibition increased sharply with tetracaine concentration. Ca-ATPase was significantly inhibited by 0.5 mM tetracaine. but inhibition was essentially linear with tetracaine concentration. In the presence of 2.5 mM tetracaine the K_0.5 for activation of NaK-ATPase by Na⁺ and K⁺ was increased 3- and 5-fold respectively. The V_max was also decreased. In the case of Ca-ATPase, tetracaine did not alter the k_0.5 for activation by Ca²⁺ but decreased V_max. These results demonstrate that NaK-ATPase is more sensitive than Ca-ATPase to inhibition by tetracaine and suggest that the non-ionized form of the local anesthetic is primarily responsible for the inhibition of both enzymes.     

Human red blood cell membrane damage by endosulfan

Endosulfan is a chlorinated hydrocarbon insecticide. Its in vitro toxicity on human red blood cell membrane was studied by staining with a fluorochrome dye, merocyanine-540 (MC-540) and Scanning Electron Microscopy (SEM). At a concentration of 0.001 microgram/ml (1 ppb) endosulfan was found to damage human red cell membranes as demonstrated by fluorescence of 30-50% of red cells on staining with MC-540. This was supported by the finding of crenation and threading of red blood cells under SEM. At concentration of 1 microgram/ml (1 ppm) the cells were markedly damaged.     

Irreversible inactivation of human red cell ATPase activity by tetracaine.

Red cell NaK- and Ca-ATPase activities are irreversibly inactivated when membranes are exposed to tetracaine under appropriate conditions. NaK-ATPase was inactivated upon exposure of membranes to tetracaine at 20° in the absence of ligands. Ca-ATPase was stable at this temperature, but inactivation could be demonstrated at 47°. The rate of inactivation of both enzymes increased with tetracaine concentration over a similar range. Inactivation also increased with pH, suggesting a correlation between the non-ionized form of the local anesthetic and inactivation of both enzymes. All ligands of NaK-ATPase with the exception of ATP afforded marked protection against inactivation by tetracaine. The degree of protection was a hyperbolic function of ligand concentration in the exposure medium. The concentration of each ligand required for half-maximal protection (K_0.5) was approximately 1mM. These results demonstrate that the binding of some ligands to NaK-ATPase stabilizes that enzyme in conformational states which are resistant to attack by tetracaine. Ca-ATPase was more resistant to inactivation by tetracaines, and ligand effects were not evident.     

Effects of red blood cell concentrate transfusion on blood tacrolimus concentration

Background Elevated blood concentration of tacrolimus is frequently observed following transfusion of red blood cell concentrate in patients after allogeneic hematopoietic stem cell transplantation. Objective The aim of this retrospective study was to clarify the effects of transfusion of red blood cell concentrate on the blood concentration of tacrolimus. Setting Chiba University Hospital in Japan. Method Fifty-two patients (aged 0–65 years) receiving both tacrolimus and transfusion after allogeneic hematopoietic stem cell transplantation were enrolled. The ratio of measurement after transfusion to measurement before transfusion was calculated for hematocrit and blood concentration/dose ratio of tacrolimus (termed the hematocrit ratio and the tacrolimus ratio, respectively). Main outcome measure Change in blood concentration/dose ratio of tacrolimus and variable factors associated with variation in tacrolimus ratio. Results The blood concentration/dose ratio of tacrolimus was increased after transfusion compared with before transfusion (p?<?0.001). A statistically significant correlation was seen between the hematocrit ratio and tacrolimus ratio (r?=?0.32, p?<?0.001). Hematocrit ratio, age or body surface area, and difference in aspartate aminotransferase level before and after transfusion were associated with the variation in tacrolimus ratio. There was no correlation between tacrolimus ratio and change in serum creatinine or potassium level in the short term. Conclusion Change in the blood concentration/dose ratio of tacrolimus was associated with change in the hematocrit ratio after transfusion, and more attention is required for children or patients with small body surface area. Dose adjustment of tacrolimus is required if the blood concentration of tacrolimus is much higher than the target concentration.

     

Intraindividual variability in red blood cell thiopurine methyltransferase activity

Objective: Long-term (13 weeks) and circadian (24 hours) intraindividual variability in red blood cell (RBC) thiopurine methyltransferase (TPMT) activity in healthy subjects was studied. Methods: RBC TPMT activity was measured radiochemically. Results: The variability in RBC TPMT activity was low and was only slightly higher than the imprecision of the TPMT assay. Mean long-term intraindividual variability in RBC TPMT activity was 6.5% (CV) (n = 46). Mean intraindividual circadian variability in RBC TPMT activity was 6.4% (CV) (n = 18). Conclusions: In contrast to what has been observed in children with acute lymphoblastic leukaemia, the intra- individual variability in RBC TPMT activity in healthy subjects was low. The reported changes in baseline RBC TPMT activity in patients are probably therefore due to drugs, disease, assay variation or other, unidentified factors. Received: 9 October 1995/Accepted in revised form: 8 January 1996