Effect of Physical Training on Sulfamethazine Acetylation Rate

We studied the rate of sulfamethazine acetylation in athletes and untrained controls aging 18-22 years. The rate of sulfamethazine acetylation in controls was characterized by a bimodal distribution: rapid and slow acetylators constituted 42 and 58%, respectively. The rate of sulfamethazine biotransformation in athletes was characterized by a trimodal distribution: ultrarapid, rapid, and slow xenobiotic acetylators constituted 48.4, 22.6, and 29%, respectively. The ultrarapid acetylation phenotype was probably associated with N-acetyltransferase induction and reflected adaptation to physical exercises.     

Heterologous structure of coating antigen on sensitivity of ELISA for sulfamethazine: evidence from molecular similarity analysis

Six structurally similar sulfonamide haptens have been linked to ovalbumin by diazo-method used as coating antigen. An enzyme-linked immunosorbent assay (ELISA) was developed to investigate heterologous structure of coating haptens on sensitivity of ELISA for sulfamethazine. The sensitivities of ELISA, expressed as IC₅₀ values, ranged from 94 to 877 ng mL^{? 1} when six coating antigens were employed. The results suggested that the structural heterology of coating hapten had significant effect on ELISA sensitivity. In order to evaluate the relationship between the degree of hapten heterology and ELISA sensitivity, we used molecular similarity methods to qualitatively represent the degree of coating hapten heterology. The Molecular Access System (MACCS) structural keys and the Tanimoto similarity coefficient were used to calculate and compare the degree of coating hapten's similarity, and the authors found that the sensitivity of ELISA was not in direct proportion with degree of coating hapten heterology in the case of study.     

120名中国人磺胺二甲嘧啶N-乙酰化表型分析

 目的：对120名健康志愿者进行了N-乙酰化表型分析。方法：以磺胺二甲嘧啶（SM₂）为探针药物，用HPLC测得受试者3h尿样，6h后尿样及血样中SM₂及乙酰化磺胺二甲嘧啶（Ac-SM₂），以Ac-SM₂摩尔百分数（Ac-SM₂％）为分型指标。结果：作频数图后，受试者均呈明显两态分布，3种样品中Ac-SM₂％值小于72％，85％，50％者被分为慢代谢者，120名受试者中慢代谢者分别为22，20，21人，对3种样品的相关分析表明方法之间相关性达0．9以上。结论：经综合分析，20名受试者可明确划分出慢代谢者，占16．6％。此研究结果将为进一步探讨应用咖啡因作为探针药物以及进一步的基因分析打下了一定基础，同时也有助于进一步明确中国人N-乙酰化分型的情况。     

一种新的血浆中磺胺二甲嘧啶及其代谢物的测定方法及在N-乙酰化分型中应用

 目的:测定血浆中磺胺二甲嘧啶及其代谢物，研究其在体内乙酰化表型。方法:用乙腈直接沉沈血浆蛋白，处理后样品在流动相为乙腈-水-醋酸(16.5:83.5:0.05)，流速1.0 ml·min^-1,紫外测定波长260 nm条件下进样。结果:磺胺二甲嘧啶和乙酰磺胺二甲嘧啶相关性分别为0. 999 9和0. 999 6。方法的平均回收率为(99. 49±3.62)%和(99.89±0.87)%。 120名健康志愿者服用磺胺二甲嘧啶片后，用本方法测定体内药物浓度，得快乙酰化者与慢乙酰化者之比为101:19。结论:方法简单、快速、灵敏，能较好地N-乙酰化酶表型。     

Bioactivation, protein haptenation, and toxicity of sulfamethoxazole and dapsone in normal human dermal fibroblasts

Cutaneous drug reactions (CDRs) associated with sulfonamides are believed to be mediated through the formation of reactive metabolites that result in cellular toxicity and protein haptenation. We evaluated the bioactivation and toxicity of sulfamethoxazole (SMX) and dapsone (DDS) in normal human dermal fibroblasts (NHDF). Incubation of cells with DDS or its metabolite (D-NOH) resulted in protein haptenation readily detected by confocal microscopy and ELISA. While the metabolite of SMX (S-NOH) haptenated intracellular proteins, adducts were not evident in incubations with SMX. Cells expressed abundant N-acetyltransferase-1 (NAT1) mRNA and activity, but little NAT2 mRNA or activity. Neither NAT1 nor NAT2 protein was detected. Incubation of NHDF with S-NOH or D-NOH increased reactive oxygen species formation and reduced glutathione content. NHDF were less susceptible to the cytotoxic effect of S-NOH and D-NOH than are keratinocytes. Our studies provide the novel observation that NHDF are able to acetylate both arylamine compounds and bioactivate the sulfone DDS, giving rise to haptenated proteins. The reactive metabolites of SMX and DDS also provoke oxidative stress in these cells in a time- and concentration-dependent fashion. Further work is needed to determine the role of the observed toxicity in mediating CDRs observed with these agents.     

Disposition of Sulfamethazine and N-Acetylsulfamethazine in the Rat

Pharmaceutical Research -     

Genetic polymorphisms of drug metabolism

The molecular mechanisms of 3 genetic polymorphisms of drug metabolism have been studied at the level of enzyme activity, enzyme protein and RNA/DNA. As regards debrisoquine/sparteine polymorphism, cytochrome P-450IID6 was absent in livers of poor metabolizers; aberrant splicing of premRNA of P-450IID6 may be responsible for this. Moreover, 3 mutant alleles of the P-450IID6 locus on chromosome 22 associated with the poor metabolizer phenotype were identified by Southern analysis of leucocyte DNA. The presence of 2 identified mutant alleles allowed the prediction of the phenotype in approximately 25% of poor metabolizers. The additional gene-inactivating mutations which are operative in the remainder of poor metabolizers are now being studied. Regarding mephenytoin polymorphism, although the deficient reaction, S-mephenytoin 4'-hydroxylation, has been well defined in human liver microsomes, the mechanism of this polymorphism remains unclear. All antibodies prepared to date against cytochrome P-450 fractions with this activity recognize several structurally similar enzymes and several cDNAs related to these enzymes have been isolated and expressed in heterologous systems. However, which isozyme is affected by this polymorphism is not known. As regards N-acetylation polymorphism, N-acetyltransferases have been purified from human liver, specific antibodies prepared; it was observed that immunoreactive N-acetyltransferase is decreased or undetectable in liver of "slow acetylators". Two genes that encode functional N-acetyltransferase were characterized. The product of one of these genes has identical activity and characteristics as the polymorphic liver enzyme. Cloned DNA from rapid and slow acetylator individuals has been analyzed to identify the structural or regulatory defect that causes deficient N-acetyltransferase.     

磺胺二甲嘧啶对FRTL-5细胞合成、分泌甲状腺球蛋白的影响

[目的 ]研究磺胺二甲嘧啶对FRTL 5细胞株合成、分泌甲状腺球蛋白的影响 ,并探讨FRTL 5细胞株用于筛选环境甲状腺素干扰物的可能性。 [方法 ]FRTL 5细胞分别经 0 .5、1.0、2 .0、4.0、和 8.0 μg/ml磺胺二甲嘧啶染毒处理48h后 ,用MTT实验检测磺胺二甲嘧啶对细胞活力的影响以确定染毒浓度 ;以MTT实验最大无作用浓度作为最高染毒浓度 ,另设中、低浓度共 3组染毒细胞 ,用放射免疫法测定染毒 48h后培养液中细胞分泌甲状腺球蛋白的浓度 ;用活细胞爬片的免疫组化染色观察最高浓度处理组细胞胞质中合成甲状腺球蛋白的表达水平 ,并用透射电镜观察细胞的超微结构。[结果 ]根据MTT实验 ,确定染毒浓度为 0 .5、1.0和 2 .0 μg/ml,随磺胺二甲嘧啶浓度的增大 ,FRTL 5细胞培养液中甲状腺球蛋白的浓度逐渐降低 ,其中 1.0 μg/ml浓度组与对照组相比差异有统计学意义 (P <0 .0 5 ) ,2 .0 μg/ml浓度组培养液中未能检出甲状腺球蛋白 ;免疫组化染色可见染毒组细胞胞质中合成的甲状腺球蛋白表达显著减弱 ,图像分析结果显示其灰度值的差异有统计学意义 (P <0 .0 5 ) ;细胞超微结构观察发现染毒组细胞出现粗面内质网扩张。 [结论 ]通过损伤甲状腺滤泡细胞的粗面内质网 ,而影响甲状腺球蛋白的合成与分泌 ,这可能是磺胺二甲嘧啶干     

一种新的血浆中磺胺二甲嘧啶及其代谢物的测定方法及在N-乙酰化分型中应用

目的：测定血浆中磺胺二甲嘧啶及其代谢物，研究其在体内乙酰化表型。方法：用乙腈直接沉淀血浆蛋白，处理后样品在流动相为乙腈水醋酸（１６．５∶８３．５∶０．０５），流速１．０ｍｌ·ｍｉｎ－１，紫外测定波长２６０ｎｍ条件下进样。结果：磺胺二甲嘧啶和乙酰磺胺二甲嘧啶相关性分别为０．９９９９和０．９９９６。方法的平均回收率为（９９．４９±３．６２）％和（９９．８９±０．８７）％。１２０名健康志愿者服用磺胺二甲嘧啶片后，用本方法测定体内药物浓度，得快乙酰化者与慢乙酰化者之比为１０１∶１９。结论：方法简单、快速、灵敏，能较好地Ｎ乙酰化酶表型。     

Production of chicken yolk IgY to sulfamethazine: comparison with rabbit antiserum IgG

Sulfamethazine was used as target analyte to produce IgY from chicken aiming to compare the performance of these two antibodies in term of yield, titer, sensitivity, selectivity and matrix effect under parallel conditions. The results showed that the total yield of IgY produced by one chicken during 43 weeks' experimental period was about 15 g. This output is much more than IgG (150 mg from one rabbit). Besides, IgY titers increased during 10 weeks and remained stable over 30 weeks. The peak titer of IgY was 1:2¹⁸. As the antibody titer rose, the sensitivity was increased. For IgG, the maximum titer was observed to be 1:2²³. In addition, both IgY and IgG were highly sensitive. The limits of detection were 0.54 ng/mL for IgY and 0.24 ng/mL for IgG. These results indicated that the IgY potentially provides a practical and ethical alternative to IgG in veterinary drug residue immunoanalysis.