Structural studies on H-2Db and H-2Kd molecules indicate that murine major histocompatibility b and d haplotype alloantigens share structural features

Structural properties of the H-2D^b and H-2K^d murine major histocompatibility complex (MHC) antigens were examined by radiochemical methods. Radiolabelled preparations of the H-2D^b and H-2K^d antigens were obtained by indirect immune precipitation of NP-40 lysates of the lymphoid tumor cell lines EL-4 (H-2^b) and C14 (H-2^d), respectively. After preparation of the 37,000 molecular weight papain fragment the antigens were cleaved with CNBr. The H-2K^d antigen yielded four major CNBr fragments whereas the H-2D^b molecule provided six. These CNBr fragments were subjected to partial NH₂-terminal amino acid sequence analysis and aligned by homology to the H-2K^b glycoprotein. Comparison of the structural properties of the H-2K^d and H-2D^b molecules with previously published data on the other known major transplantation antigens of the b and d haplotypes (H-2K^b, H-2D^d and H-2L^d) reveal a marked structural similarity. First, the data show that certain methionine residues have been highly conserved and that cleavage by CNBr at these positions provides an initial strategy for the study of these molecules. Secondly, disulfide-linked peptides obtained after CNBr cleavage could be aligned and the data suggest the presence of disulfide bridges in homologous positions. Third, after CNBr cleavage both the H-2K^d and H-2D^b molecules yielded two glycopeptides which were homologous to glycopeptides from the H-2K^b molecule. Fourth, overall homology for a limited number of comparable positions is about 81% between the H-2K^b and H-2K^d gene products and 88% between the H-2K^b and H-2D^b gene products.     

Trophic action of pharmacological substances with a guanidine group on mouse neuroblastoma cells and chick ganglionic neurons in culture

A series of substances (designated CTQ compounds) with a guanidine group have been synthesized and tested for their ability to promote neuronal survival and neurite outgrowth. Mouse neuroblastoma clonal cell lines grown in serum-containing medium for 10 days as well as primary cultures of embryonic chicken ganglion neurons grown in serum-free defined medium for 1 or 2 days have been used for the experiments. Among the various CTQ compounds (CTQ1–CTQ20) tested, only CTQ8 exerted positive neurotrophic effects on these peripheral neuronal cells. At a concentration of 10⁻⁴ M, CTQ8 enhanced neuritogenesis of neuroblastoma cells. However, the most striking influence of CTQ8 was its promoting effect (6- to 10-fold) on the survival of chicken ciliary and dorsal root ganglionic neurons at concentrations ranging from 10⁻³ M to 5×10⁻⁴ M.     

Regional differences of the effect of σ receptor ligands on the acetylcholine release in the rat brain

Summary We found that a receptor ligands differentially regulated the acetylcholine (ACh) neurotransmission in the rat brain. Acute administration of (+)-N-allylnormetazocine [(+)-SKF-10,047], a prototype ₁ receptor ligand, and 1,3-di(2-tolyl)guanidine (DTG), a non-specific receptor ligand, increased the extracellular ACh level in the rat hippocampus. This increase of hippocampal extracellular ACh level elicited by (+)-SKF-10,047 was more potent than that elicited by DTG. On the other hand, the striatal extracellular ACh level was slightly affected by (+)-SKF-10,047. In addition, DTG did not affect the striatal extracellular ACh level. Our previous studies have shown that both (+)-SKF-10,047 and DTG increased the extracellular ACh level in the rat frontal cortex. Taking all these data into consideration, the regulation of ACh neurotransmission by receptor ligands are different depending upon the brain region.     

A New Approach to Study the Physical Stability of Monoclonal Antibody Formulations—Dilution From a Denaturant

The early-stage assessment of the physical stability of new monoclonal antibodies in different formulations is often based on high-throughput techniques that suffer from various drawbacks. Accordingly, new approaches that facilitate the protein formulation development can be of high value to the industry. In this study, a dynamic light scattering plate reader is used to measure the aggregation (by means of the increase in the hydrodynamic radius [R_h]) of monoclonal antibody samples that were subject to incubation and subsequent dilution from different concentrations of a denaturing agent, that is, guanidine hydrochloride. The increase in the R_h of the protein samples is dependent not only on the denaturant concentration used but also on the buffer in which the incubation/dilution was performed. We also compare the aggregation after dilution from a denaturant with other high-throughput stability-indicating methods and find good agreement between the techniques. The proposed approach to probe the physical stability of monoclonal antibodies in different formulation conditions offers a unique combination of features—it is isothermal, probes both the resistance to denaturant-induced unfolding and the colloidal protein stability, it is entirely label-free, does not rely on complex data evaluation, and requires very short instrument measurement time on standard equipment.     

A novel automated assay for malate dehydrogenase isoenzymes

We have developed a new automated method for the determination of malate dehydrogenase (MDH) isoenzymes in serum employing guanidine hydrochloride. Our proposed method showed good reproducibility; within-run precision coefficient of variations (CVs) were less than 2.5 (mean 13.6–42.9 U/L) for total MDH (T-MDH) and less than 6.7% (mean 6.3–23.6 U/L) for mitochondrial MDH (m-MDH) (n = 10). The upper detection limit of the proposed method exhibited good linearity up to 1,000 U/L for both T-MDH and m-MDH. In the proposed m-MDH reagent, the presence of up to 2,000 U/L of cytosolic MDH(c-MDH) activity had no effect on the outcome of m-MDH assay. Results of our proposed method (y) correlated well with those of the electrophoretic method (x) giving the regression equation: y = 1.46 x + 6.87 (N = 30); r = 0.99. Normal concentrations of various anticoagulants and bilirubin did not affect the assay results. Both ascorbic acid and glucose exhibited a slight positive interference with the proposed assay. Clinically, we found that m-MDH activity in serum had greater diagnostic predictive value than T-MDH activity for judging successful outcome of reperfusion therapy; the prognosis was poor when the m-MDH/T-MDH ratio was greater than 20%. © 1996 Wiley-Liss, Inc.     

聚六亚甲基胍的中和剂选择及其杀菌效果试验观察

目的观察一种以聚六亚甲基胍为主要杀菌成分的消毒剂杀菌效果。方法采用悬液定量杀菌试验方法进行了实验室试验。结果该消毒剂主要杀菌成分聚六亚甲基胍含量为5000mg/L～6000mg/L。设计4组中和剂配方,只有含20g/L卵磷脂+20g/L吐温80TPS组成的中和剂符合规范要求。用含量为500mg/L聚六亚甲基胍消毒液,对悬液内金黄色葡萄球菌作用1.0min,杀灭对数值均5.00;作用3.0min,可达到完全杀灭。结论聚六亚甲基胍消毒剂杀菌试验必须选择合适的中和剂,其可有效杀灭金黄色葡萄球菌。     

~(123)I-间碘苄胍心肌显像对慢性心力衰竭的诊断价值

目的:评价123I-间碘苄胍心肌显像对慢性心力衰竭的诊断价值。方法:共检测对象30例,其中慢性心力衰竭患者15例,正常对照健康志愿者15例。采用123I-MIBG行早期(20 min)及延迟(3 h)平面心肌显像,采用心/上纵隔(H/M)作相对半定量分析。结果:两组早期(H/M)均低于延迟相(P<0.01);心力衰竭组早期与延迟H/M均低于正常对照组(P<0.01),M IBG洗脱率(WR)高于正常对照组(P<0.01)。结论:123I-间碘苄胍显像能发现慢性心力衰竭患者早期肾上腺素能神经功能受损,是评价心力衰竭早期自主神经病变的无创伤性指标。     

麻黄干浸膏及其单宁成份治疗慢性肾功能衰竭的实验研究

经口投入麻黄干浸膏及其单宁成分，探讨对Ａｄｅｎｉｎｅ法诱发的慢性肾功能衰竭（肾衰）大鼠的治疗作用及其机制。结果发现：同期投药及诱发后投药，麻黄干浸膏能使肾衰大鼠血中尿素氮下降３７．％，肌酐下降３５５、甲基胍下降７６％、胍基琥珀酸下降８３％，血磷下降３９％、血钙升高２８％，尿中甲基胍排泄量平均降低４９％－６５％。表明麻黄干浸膏可明显改善慢肾衰大鼠的肾功能，纠正高磷低钙血症，特别是明显抑制甲基胍的产生     

1-烷基-3-[4-(苯并噻唑-2-巯基)苯基]胍类化合物的合成及其生物活性

目的：合成1-烷基-3-[4-（苯并噻唑-2-巯基）苯基]胍类化合物，寻找有一氧化氮合酶（NOS）抑制活性的新型化合物。方法：以N-苯基胍为母核，在苯基对位引入苯并噻唑-2-巯基，胍中其他氮上分别引入烷基、环烷基、芳烷基等，并测定这些胍类化合物的NOS抑制活性。结果和结论：合成了13个胍类化舍物，其结构经IR、^1H NMR、MS和元素分析得到确证；初步药理实验结果表明，在10^-6mol／L浓度下，测得5个化合物（Ⅱ6，Ⅱ7，Ⅱ8，Ⅱ11，Ⅱ12）对大鼠腹腔巨噬细胞释放NO有一定的抑制作用，其中化合物Ⅱ7的抑制率大于15％。其他样品在此浓度下未观察到明显变化。     

天然产物中抗HIV生物碱类化合物的研究进展

近年来,从天然产物中寻找高效低毒的先导化合物已成筛选抗HIV药物的重要研究方向。生物碱类化合物作为一类重要的天然产物,数量众多,结构类型复杂,其中有多种抑制和阻断HIV感染的有效成分,通过实验室研究工作和临床用药观察,有望从中获得抗HIV的有效药物。以生物碱类化合物的化学结构为基础,将生物碱类化合物分为异喹啉类、喹啉类、大环类、哌啶类、莨菪烷类、吲哚类、咔唑类、海洋多环胍类、萜类、manzamine型生物碱等10类,对其抗HIV活性进行综述。