Structural diversity among anti-p-azophenylarsonate monoclonal antibodies from A/J mice: Comparison of Id and Id sequences

Amino acid sequence analyses were carried out on monoclonal anti-p-azophenylarsonate antibodies isolated from the ascites of mice carrying cell lines obtained from the fusion of A/J splenic lymphocytes with the myeloma cell line Sp2/0–Ag14. The partial primary structures of both heavy and light chains from seven idiotype negative hybridoma proteins are compared to those of six idiotype positive molecules. Amino-terminal amino acid sequences (40–47 residues) of heavy chains from molecules bearing the major cross-reacting idiotype, Id^CR, demonstrated 95% homology to each other. Similarly, aminoterminal sequences of Id^CR+light chains were homologous to each other. However, sequence variations were evident in individual antibodies in both framework and complementarity-determining regions, suggesting that a large family of molecules accounts for the major cross-reacting idiotype, as previously reported (Marshak-Rothstein et al., 1980b).

Heavy and light chains from seven Id^CR-negative monoclonal antibodies were subjected to amino-terminal (37–48 residues) amino acid sequence analysis. Four heavy chains were blocked to Edman degradation, but could be sequenced after enzymatic removal of the amino-terminal pyrrolidone carboxylic acid residue. In comparison with Id^CR-positive heavy chains, the Id^CR-negative heavy chains demonstrate greater diversity in both framework and complementarity-determining regions, with several different subgroups represented in contrast to the results from pooled serum Id^CR-positive antibodies (Capra et al., 1975). One of the seven Id^CR-negative light chains was blocked. The sequences of the remaining Id^CR-negative light chains exhibited marked variations in both framework and complementarity-determining regions, with different chain lengths in the first complementarity-determining region in several light chains.

Comparisons between the amino-terminal sequences of Id^CR-positive and Id^CR-negative monoclonal antibodies suggest that specific sequences in the first complementarity-determining regions of both heavy and light chains are not sufficient to account for the major cross-reacting idiotype. The structural basis for Id^CR in A/J mice is likely to be in other segments of the variable regions.     

Cytochemical manifestations of short- and long-term activation of the rat brain dopaminergic system

Laboratory of Cytochemistry, Brain Research Institute, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR O. S. Adrianov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 112, No. 7, pp. 41–42, July, 1991.     

肝癌相关性甘氨酰脯氨酸二肽氨基肽酶检测法

目的：进一步探讨血清肝癌相关性GPDA同工酶分离检测条件,提高其对原发性肝癌的诊断价值。方法：对分离血清肝癌相关性GPDA同工酶电泳体系的凝胶浓度及梯度、缓冲液的pH及离子强度、电泳的环境温度、标本 用量以及呈色条件等进行了逐项摸索,建立了稳定且分离效果好的GPDA同工酶检测方法。结果：采用三层阶段梯度聚丙烯酰胺凝胶体系将血清GPDA分为肝癌相关性的快带（GPDA－F）和相关性的慢带（GPDA－S）,肝癌相关性GPDA的检出率明显提高。结论：肝癌相关性血清GPDA检测法稳定可靠、敏感,适合于临床推广应用。     

Development and in Vitro Evaluation of Systems to Protect Peptide Drugs from Aminopeptidase N

Purpose. Develop and evaluate systems to prevent aminopeptidase N caused enzymatic degradation of perorally administrated peptide drugs. Methods. Bacitracin was covalently bound to the unabsorbable carrier matrix poly(acrylic acid) (paa) in order to avoid any dilution effects of the inhibitor in the intestine as well as systemic toxic side effects. The inhibitory effect of this conjugate, of neutralized paa and N-acetylcysteine was evaluated using a brush border membrane model. Results. Whereas within 6 h of incubation 65.3 ± 3.7 mol/1 of the substrate (L-leucine p-nitroanilide) was hydrolyzed under our assay conditions, this metabolism was reduced to 44.5 ± 6.3 mol/1 and 49.0 ± 8.8 mol/1 (n = 3–5; ± S.D.) using 1.5% bacitracin-polymer conjugate and 0.5% N-acetylcysteine, respectively. The same amount of bacitracin as immobilized to the polymer exhibited a comparably weaker inhibitory effect. Neutralized paa did not inhibit membrane bound aminopeptidase N. Covering the membrane with a thin mucus layer led to a significantly lowered inhibitory effect of all tested agents. Conclusions. The immobilization of enzyme inhibitors to a carrier matrix and the use of N-acetylcysteine as a novel inhibitor are promising strategies in order to overcome the enzymatic barrier caused by membrane bound peptidases. However the use of effective mucolytic agents seems to be a prerequisite.     

Structural Specificity of Mucosal-Cell Transport and Metabolism of Peptide Drugs: Implication for Oral Peptide Drug Delivery

The brush border membrane of intestinal mucosal cells contains a peptide carrier system with rather broad substrate specificity and various endo- and exopeptidase activities. Small peptide (di-/ tripeptide)-type drugs with or without an N-terminal -amino group, including -lactam antibiotics and angiotensin-converting enzyme (ACE) inhibitors, are transported by the peptide transporter. Poly-peptide drugs are hydrolyzed by brush border membrane proteolytic enzymes to di-/tripeptides and amino acids. Therefore, while the intestinal brush border membrane has a carrier system facilitating the absorption of di-/tripeptide drugs, it is a major barrier limiting oral availability of polypeptide drugs. In this paper, the specificity of peptide transport and metabolism in the intestinal brush border membrane is reviewed.     

尿甘氨酰脯氨酸二肽氨基肽酶与高血压血清脂质的关系

目的探讨尿甘氨酰脯氨酸二肽氨基肽酶(GPDA)与高血压病患者血清脂质变化的关系。方法检测130例高血压病患者,98名正常人(为对照组)的尿GPDA和血清脂质的水平。结果高血压病患者尿GPDA明显高于正常对照组(P<0.001)。尿GPDA升高的高血压病患者血清胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、胆固醇/高密度脂蛋白胆固醇比值(TC/HDL-C)、LDL-C/HDL-C比值、载脂蛋白B(apoB)、脂蛋白(a)犤Lp(a)犦水平均高于尿GPDA正常的高血压病患者组和正常人对照组,而HDL-C、载脂蛋白A1(apoA1)、apoA1/apoB比值则均低于尿GPDA正常的高血压病患者组和正常人对照组。结论高血压病患者尿GPDA水平可能反映其脂质代射水平。     

尿甘氨酰脯氨酸二肽氨基肽酶测定对系统性红斑狼疮患者早期肾损害的诊断价值

目的　探讨尿甘氨酰脯氨酸二肽氨基肽酶 (GPDA)对系统性红斑狼疮 (SLE)患者早期肾损害的诊断价值。方法　采用连续检测法测定 4 2例SLE患者和 30例正常人尿GPDA活性 ,并与尿微量白蛋白 (mAlb)相比较。结果　SLE患者尿GPDA及mAlb测定结果均明显高于对照组 (P均 <0 .0 0 1) ,2组指标有显著性差异。结论　尿GPDA能敏感反映SLE患者早期肾损害 ,具有重要临床诊断价值     

抗癌作用新靶点及其抑制剂的研究进展

针对靶点分子或某种发生发展机制来设计抗肿瘤药物的研究工作已取得了相当大的成就.这类药物的特异性强,疗效显著,因此,针对这些新靶点进行药物设计可以使抗肿瘤药物的研究产生一次新的革命.本综述旨在讨论目前抗肿瘤药物研究的潜在的新靶点以及它们相应的抑制剂或拮抗剂.     

Caries Frequency and Nutrition Before,During and After World War II

This study was carried out in order to observe the changes in amino-peptidase activity which might occur in the palatal mucosa and gingiva of the rat in the initial phase of healing after tooth extractions. The material consisted of 115 male Sprague-Dawley rats. Amino-peptidase activity was studied at time intervals of 30 min., 1, 2, 4, 8, 16 hours and 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 days after the extractions. The azocoupling principle was used for the histochemical demonstration of enzyme activity. However, the incubation solution was in gel form. A semipermeable membrane was placed between the tissue sections and the incubation medium in order to prevent enzyme diffusion and dissolving of enzymes into the incubation medium. The substrates used were N-aminoacyl 2-naphthylamines of L-leucine and L-arginine. Histological investigations were carried out simultaneously with the histochemical study. The principal increase in aminopeptidase activity occurred relatively late after the tooth extractions. The most intense staining was observed in 4- to 7-day wounds. During the same period the most active fibroblastic proliferation was observed histologically. The changes were demonstrable using both of the substrates. However, the staining was more intense when N-L-leucyl-2-naphthylamine was used as the substrate. By using N-L-arginyl-2-naphthylamine as the substrate, chloride ions caused a marked increase in staining intensity. It was thus assumed that aminopeptidase B would also be activated during the healing.     

Multiple gastric involvement by myeloid antigen CD13-positive non-secretory plasma cell leukaemia

Gastrointestinal tract involvement is a rare complication of plasma cell neoplasia. We present a case of non-secretory type primary plasma cell leukaemia (PCL) with multiple gastric involvement. Dual surface antigen analysis of bone marrow cells revealed that atypical plasma cells coexpressed CD38 and myeloid antigen CD13. Upper gastrointestinal endoscopy disclosed multiple submucosal masses in the body of the stomach. Endoscopic biopsy specimens showed marked infiltration of atypical plasma cells consistent with a diagnosis of gastric involvement by PCL. Since CD13 antigen is identical to aminopeptidase N, a membrane-bound glycoprotein thought to be involved in the process of tumour invasion, CD13 expression on neoplastic plasma cells may be related to the gastric involvement in this patient.