Pharmacokinetics, metabolism and renal excretion of sulfatroxazole and its 5-hydroxy- and N4-acetyl-metabolites in man

Hydroxylation is the predominant pathway of metabolism for sulfatroxazole in the body, accounting for 70 per cent of the dose. Fifteen per cent of the dose is acetylated unimodally and 10 per cent is excreted unchanged. The half-lives of sulfatroxazole and its metabolites 5-hydroxysulfatroxazole and N4-acetylsulfatroxazole are approximately 22 h after administration of sulfatroxazole. N4-acetylsulfatroxazole, taken as parent drug, is eliminated by renal excretion (92 per cent of the dose). The initial elimination half-life of N4-acetylsulfatroxazole is 4.5 h, which later increases to 70 h as the result of the acetylation-deacetylation equilibrium. Probenecid inhibits the renal excretion of the metabolites 5-hydroxy- and N4-acetylsulfatroxazole. Inhibition of the N4-acetyl metabolite favours the deacetylation, which results in an increase of the T 1/2 of sulfatroxazole from 20 to 30 h. The protein binding value of sulfatroxazole is 84 per cent, that of N4-acetylsulfatroxazole is 37 per cent. Sulfatroxazole is excreted renally by passive processes, while the metabolites are excreted by both passive and active processes.     

Influence of Genetic Variation in the C-Reactive Protein Gene on the Inflammatory Response During and After Acute Coronary Ischemia

The aim of this research was to assess whether common genetic variants within the C-reactive protein gene ( CRP ) are related to the degree of acute rise in plasma C-reactive protein (CRP) levels following an acute coronary syndrome (ACS). While polymorphisms within CRP are associated with basal CRP levels in healthy men and women, less is known about the relationship of such genetic variants and the degree of CRP rise during and after acute ischemia. Plasma CRP is associated with increased rates of recurrent coronary events. We evaluated seven common genetic variants within CRP and assessed their relationship to the degree of rise in CRP levels immediately following an acute coronary syndrome in 1827 European American patients. Variants in the putative promoter region, −757T > C and −286C > T > A, were associated with the highest CRP elevations after ACS. Patients with two copies of the A allele of SNP −286C > T > A had median CRP values of 76.6 mg/L, compared to 11.1 mg/L in patients with no copies of the rare variant (p-value <0.0001), post ACS. The lowest CRP values were found for patients with minor alleles of the exonic 1059G > C and the 3'untranslated region 1846G > A SNPs. For example, patients homozygous for the minor allele of 1059G > C had 71% lower median CRP values than those homozygous for the major allele [3.5 vs 12.0 mg/L, p < 0.0001]. These trends persisted in the chronic stable phase after ischemia had resolved, and after adjustment for infarct size by peak creatinine kinase levels and clinical status by Killip class. Assessment of CRP genetic variants identified patients with higher and lower CRP elevation after acute coronary syndrome.     

稳定性核素测定大鼠小肠蛋白质合成

目的：建立稳定性核素（[L-^15N]亮氨酸）测定大鼠小肠蛋白质合成率的方法。方法：分别测定静脉注射相同剂量[L-^15N]亮氨酸不同时相的大鼠小肠^15N丰度及不同剂量[L-^15N]亮氨酸同一时相的大鼠小肠^15N丰度。结果：大鼠小肠游离氨基酸池中^15N核素丰度在注射后0．5h内呈线性上升并达高峰，维持4h后缓慢下降，小肠蛋白质中的^15N丰度0．5h至12h基本维持不变；随着注射剂量的增加，大鼠小肠蛋白质分数合成率（FSR）亦增加，当[L-^15N]亮氨酸剂量在1．0mmol／kg以上，FSR并不随施加[L15N]亮氨酸剂量的加大而增加。结论：在进行大鼠小肠蛋白质合成率测定时，一次性静脉注射的测量最佳时限为0．5h，剂量为1．0mmol／kg。     

Inhibition of NMDA-induced protein kinase C translocation by a Zn chelator: Implication of intracellular Zn

The role of intracellular Zn²⁺ in the translocation of protein kinase C from cytosol to membrane fractions was examined by the [³H]phorbol 12,13-dibutyrate (PDBu) binding method in guinea pig cerebral synaptoneurosomes. N-methyl-d-aspartate (NMDA, 100 μM) and calcium ionophore A23187 (0.3–30 μM) decreased the binding activity in the cytosol with a concomitant increase in the membrane fractions. Pretreatment of synaptoneurosomes with a heavy metal chelator, N,N,N′,N′-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN), inhibited the NMDA- and A23187-induced changes of the distribution of [³H]PDBu binding sites in cytosol and membrane fractions. The inhibitory effect of TPEN was negated by a preincubation of TPEN with equimolar Zn²⁺ but not by that with Ca²⁺. The addition of 500 μM Zn²⁺ to the lysate of synaptoneurosomes induced an increase of [³H]PDBu binding activity in the membrane fraction with a concomitant decrease in the cytosol fraction, as did 100 μM Ca²⁺. Low concentrations of Zn²⁺ (10 μM), which alone had no effect on the distribution of the binding, significantly enhanced the effect of 10 μM Ca²⁺ in the lysate. Under those conditions TPEN inhibited the Zn²⁺-potentiated Ca²⁺-dependent changes in the binding. These results suggest that intracellular Zn²⁺ is essential for the agonist-induced translocation of protein kinase C in guinea pig synaptoneurosomes.     

9 Survivin反义寡核苷酸对人肝癌细胞的抑制作用

目的:探讨survivin反义寡核苷酸（ASODN）对人肝癌细胞HepG2的抑制作用。方法:采用免疫组织化学法检测肝细胞癌（HCC）组织中survivin的表达。采用脂质体介导survivin ASODN体外转染人肝癌细胞株HepG2，Western blot检测细胞survivin蛋白的表达，FCM检测细胞的凋亡率，观察细胞在软琼脂中的集落形成能力。建立人肝癌裸鼠皮下移植瘤模型，观察survivin ASODN的体内抑癌作用。 结果:（1）肝癌组织中survivin表达阳性率为75.8％(25/33)，明显高于癌旁组织和正常肝组织(P<0.01);（2）survivin ASODN体外转染可明显下调HepG2细胞survivin蛋白表达，ASODN组HepG2细胞凋亡率明显高于空白对照组和SODN组(P<0.01)，ASODN组HepG2细胞在软琼脂中形成的集落数目明显少于空白对照组和SODN组(P<0.01);（3）ASODN组瘤体生长速度较空白对照组和SODN组明显减慢(P<0.01)，ASODN组瘤体重量较空白对照组和SODN组明显减轻(P<0.05)。结论:Survivin在HCC组织中高表达;survivin ASODN可以诱导HepG2细胞凋亡，在体外实验和动物实验中对HepG2细胞生长都有抑制作用。     

胰腺癌中p16基因甲基化改变及其蛋白表达分析

目的:探讨胰腺癌与癌旁组织中p16基因启动子区异常甲基化的改变及其蛋白表达的特点,以及其与胰腺癌发生发展的关系。方法:分别采用免疫组化SP法及甲基化特异PCR(MSP)检测46例人胰腺癌和癌旁组织中p16基因表达及其甲基化的水平,并结合临床资料进行分析。结果:胰腺癌中p16蛋白表达率为41.3%(19/46),而癌旁组织表达率为95.7%(44/46),两者有差异显著性(P<0.01)。p16蛋白阳性的19例胰腺癌标本中均未检出基因甲基化;p16蛋白缺失的27例标本中有18例检出基因甲基化,甲基化率为39.1%。p16基因甲基化与蛋白缺失有明显关系(P<0.05)。p16基因表达及其启动子区甲基化的发生率与胰腺癌的大小,患者性别﹑年龄的差异无显著意义(P>0.05),但与组织分化程度﹑淋巴结转移﹑PTNM分期有显著意义(P<0.05)。结论:p16基因启动子的异常甲基化可影响p16蛋白的表达,它们与胰腺癌的发生发展有关;p16甲基化和蛋白表达可能成为胰腺癌诊断及预后的候选标志物之一。     

神经肽Y对心肌蛋白质合成的影响及其意义

用~3H-亮氨酸参入法与放射免疫分析法分别测定大鼠心肌蛋白质合成速度与心脏组织中神经肽Y(NPY)含量。结果显示NPY能显著促进心肌蛋白质合成,其最大效应较去甲肾上腺素(NE)大35%,所需浓度是NE的1/100。心肌梗塞后非梗塞区组织内NPY的含量在2天时无显著改变,15天时则降低71%,提示2～15天期间该区域NPY释放增加,此为非梗塞区心肌肥大的机制之一     

补肾中药对肾虚骨质疏松症大鼠红细胞膜PKC、 Ca2+-Mg2+- ATP酶活性影响的实验研究

本实验研究切除卵巢造成肾虚骨质疏松症大鼠模型。通过观测红细胞膜蛋白激酶Ｃ（ＰＫＣ）和Ｃａ２＋－Ｍｇ２＿－ＡＴＰ酶的活性，探讨肾虎骨质疏松症病理机制中肌醇脂质系统的变化，并结合全身和脊柱骨密度（ＢＭＤ）指标观察了补肾中药（密骨灵）的疗效，与正常对照组、模型空白组和阳性药（骨疏康颗粒剂）对照组进行对照，探讨补肾法的防治机理。结果表明；模型空白组大鼠红细胞膜ＰＫＣ和Ｃａ２＋－Ｍｇ２＋－ＡＴＰ酶、Ｍｇ２＋－ＡＴＰ酶的活性明显低于正常组（ｐ均＜０．０５）；密骨灵组与骨疏康组大鼠全身、脊柱ＢＭＤ和红细胞膜ＰＫＣ、Ｃａ２＋－Ｍｇ２＋－ＡＴＰ酶的活性均明显高于模型空白组（ｐ均＜０．０５），并且与正常组大鼠无明显差别（ｐ均＞０．０５）；密骨灵组大鼠红细胞膜Ｍｇ２＋－ＡＴＰ酶活性高于模型空白组和骨疏康组（ｐ＜０．０５），并且与正常组无显著性差异（ｐ＞０．０５）；密骨灵组大鼠红细胞膜ＰＫＣ活性高于骨疏康组（Ｐ＜０．０５）。结论：肾虎骨质疏松症具有红细胞膜ＰＫＣ和Ｃａ２＋－Ｍｇ２＋－ＡＴＰ酶、Ｍｇ２＋－ＡＴＰ酶活性的改变；密骨灵可以恢复肾虎骨质疏松症大鼠全身骨量，达到防治目的；补肾中药可以恢复红细胞膜ＰＫＣ活性和钙镁泵的活性，是补     

二甲亚砜对人表皮的核酸和蛋白质合成的影响

用体外培养的人的伪表皮作为模型，进行药物毒理学作用的研究，观察了二甲亚砜（ＤＭＳＯ）在不同浓度和不同接触时间条件下，对人的伪表皮细胞脱氧核糖核酸（ＤＮＡ）、核糖核酸（ＲＮＡ）和蛋白质合成的影响：随着接触时间的延长，ＤＮＡ、ＲＮＡ和蛋白质合成均受抑制。低浓度条件下（１％），ＤＮＡ、ＲＮＡ和蛋白质合成增加；在１５～５０％浓度下，ＤＮＡ和蛋白质合成抑制，而ＲＮＡ合成仍增加；在高浓度条件下（７０％～１００％），ＤＮＡ、ＲＮＡ和蛋白质合成均明显抑制。     

重组O-GLcNAc糖基转移酶在昆虫细胞中的表达和纯化

蛋白质的 O- Glc NAc糖基化修饰是一种细胞核蛋白与细胞浆蛋白的蛋白质翻译后修饰。不同于膜蛋白和分泌蛋白的糖基化修饰 ,与蛋白质磷酸化修饰相似。催化蛋白质 O- Glc NAc糖基转移酶 ( OGT)已被克隆。用Hi5昆虫细胞系统表达并纯化了具有活性的重组 OGT。在 Hi5昆虫细胞中表达的鼠肝 OGT带有一 His 6标记片段。经镍离子螯合柱纯化后 ,其比活性达到 0 .88nmol· min- 1·m g- 1 OGT。因此本研究为进一步研究蛋白 O- Glc NAc糖基化修饰提供重要资源