Inhibition of bovine platelet function by T-2 toxin, HT-2 toxin, diacetoxyscirpenol and deoxynivalenol

The aggregation of bovine platelets suspended in homologous plasma is inhibited in the presence of T-2 toxin, HT-2 toxin, diacetoxyscirpenol (DAS) or deoxynivalenol (DON) when either collagen or ADP is used as the stimulatory agent for aggregation. For each of the mycotoxins the degree of inhibition is dependent on the amount of trichothecene present in the platelet suspension but is not dependent on the time of exposure of the platelets to the toxin. For both ADP- and collagen-stimulated platelets, the order of potency of inhibition is T-2 toxin greater than HT-2 toxin greater than DAS greater than DON. A significant (P less than 0.01) dose-dependent decrease was also observed in the amount of the thromboxane B2 released from collagen-stimulated platelets in the presence of each of the mycotoxins.     

Comparison of the Biological and Immunological Activities of Serum Luteinizing Hormone and Follicle Stimulating Hormone in Infertile Males

Summary:  The biological and immunological activities of luteinizing hormone (LH) and follicle stimulating hormone (FSH) in the serum of infertile males were determined by radioreceptor (RRA) and radioimmunoassay (RIA), respectively.
In some sera the biological activity of serum LH was lower than expected on the basis of the RIA-data. In contrast, some sera contained unusually high levels of biologically active LH as demonstrated by RRA, despite not being detected in these amounts by RIA.
Prolonged exposure of the gonad to such high levels of biologically active LH might cause end-organ desensitization resulting in infertility. The detection of such cases by the use of RRA could permit therapy in these individuals or exclude patients from treatment.
Zusammenfassung:  Vergleich der biologischen und immunologischen Aktivitäten des luteinisierenden und des follikelstimulierenden Mormons aus dem Serum infertiler Männer
Die biologischen und immunologischen Aktivitäten des luteinisierenden Hormons (LH) und des follikelstimulierenden Hormons (FSH) im Serum infertiler Männer wurden durch Radiorezeptor-Assay (RRA) und Radioimmun-Assay (RIA) ermit-telt.
In einigen Seren mit relativ hohen immunologischen LH-Aktivitaten waren die biologischen LH-Aktivitäten niedriger als erwartet. Demgegenüber konnten bei einigen Proben überdurchschnittlich hohe Werte für biologisch aktives LH nachgewiesen werden, obwohl diese Seren bei RIA normale LH-Werte aufwiesen.
Eine andauernde Exposition der Gonaden solch hoher Mengen an biologisch aktivem LH, die durch RIA nicht aufgedeckt werden, kdnnte eine Gonaden-Insensitivität gegenüber diesem Hormon und damit Infertilität verursachen. Die Erfassung solcher Fälle mittels Radiorezeptor-Assay könnte die Therapie dieser Individuen ermöglichen bzw. sie von der Therapie ausschließen.     

A double determinant sandwich immunoassay for quantitation of serum monoclonal anti-I-A antibody

A double-determinant sandwich radioimmunoassay (RIA) is described for the specific detection of anti-I-Ak monoclonal antibody (mAb) in the sera of non-Ighb murine hosts undergoing anti-Ia immunotherapy. This RIA utilizes 2 previously undescribed mAb reagents generated against an Ia.17-specific mAb secreted by the 10-3.6 hybridoma. The first reagent, 7.34, is specific for Ighb-linked allotypic determinants on the Fc portion of IgG2a immunoglobulins as defined by the pattern of reactivity with normal sera from a panel of inbred and Igh recombinant inbred strains. The second reagent, 58.3, is an anti-idiotypic mAb recognizing unique determinants in the combining site of 10-3.6 immunoglobulins, as determined by the specificity of the 58.3 mAb in solid-phase RIA and the capacity of this reagent to inhibit the binding of labeled 10-3.6 mAb to I-Ak-expressing spleen cells. In an RIA procedure using purified 58.3 mAb as substrate and 125I-labeled 7.34 as the detection reagent, serum concentrations of 10-3.6 as low as 1-5 ng/ml can be measured reproducibly after mathematical linearization of the sigmoid standard curve. In the present studies, the serum half-life of 10-3.6 mAb was calculated from assay data to be 3-5 h in I-Ak homo- or heterozygotes and 72 h in non-I-Ak mice. The serum level of 10-3.6 as a function of the mAb treatment protocol was also examined and results are considered with respect to the efficacy of different therapeutic regimens in prolonging transplant survival. Sandwich immunoassays of this type (RIA or ELISA) should provide a highly sensitive and specific means for monitoring serum mAb levels in individuals subjected to antibody immunotherapy for treatment of autoimmune disease, transplant rejection or tumor progression.     

Early adrenalectomy stimulates subsequent growth and development of the rat brain

Rats were adrenalectomized (ADX) or sham-operated (SHAM) on the 11th day of life and subsequent brain development (cerebrum and cerebellum) studied in terms of tissue weight and biochemical composition. Measured at about 65 days of age, early ADX subjects had significantly heavier brains (in terms of both wet and dry weights) than SHAMs, despite being lighter in overall body weight. Brain protein and DNA contents were elevated, as was the activity of 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNP), a myelin marker enzyme. Glycerol-3-phosphate dehydrogenase (GPDH), a glucocorticoid-regulated enzyme, was reduced in activity. Although both the cerebrum and cerebellum showed the growth-enhancing effects of early adrenalectomy, the DNA and CNP changes were most pronounced in the cerebrum. Finally, the effect of adrenal removal on myelinogenesis was confirmed by subcellular fractionation experiments demonstrating that more myelin could be recovered from the brains of ADX than from SHAM animals. These results are significant in terms of the influence of adrenal secretions on normal brain development and the role of GPDH in myelin lipid biosynthesis.     

塑料球固相二抗通用分离剂在RIA中的应用

本文报道以聚苯乙烯塑料球为载体．经化学处理制成固相二抗，作为ＲＩＡ技术中的通用分离剂，并先后用于半抗原及大分子蛋白质类的测定。实验结果表明：塑料球固相二抗制备法工艺简便，最佳包被条件为１００ｍｍｏｌ／ＬＰＨ４．８柠檬酸盐缓冲液，不需特殊条件，便于推广应用。本方法不需离心，且各项指标均达对照ＰＲ分离法的标准。     

Passive smoking under controlled conditions

Summary Ten healthy subjects were exposed to passive smoking at a high level corresponding to 25–30 ppm CO in the ambient air for 3 h. All subjects were exposed at the same time in a climatic chamber especially designed for exposure experiments. Despite an identical exposure rate considerable interindividual variability of subsequent nicotine and cotinine levels in saliva, plasma and 24-h urine were observed. This variability was more prominent in nicotine than in cotinine levels. The kinetic pattern as reflected by saliva levels for up to 24 h was consistent with previous data found in active smokers. Nicotine levels found in saliva were markedly influenced by repeated sampling. This was not the case for cotinine levels. With regard to laboratory techniques RIA seems to be more sensitive than gaschromatography (GC). The results of this study suggest that measuring cotinine levels in 24-h urine with RIA is presently the most sensitive and reliable criterion for estimating exposure to passive smoking and for validating questionnaires or interviews about short-term exposure to passive smoking.     

咪苯嗪酮对TXA2和HHT生成的选择性抑制作用

咪苯嗪酮(CI-914)能抑制大鼠血小板环氧酶和TXA₂合成酶产物HHT的生成,而对脂氧酶产物12-HETE的生成仅高浓度药物才有弱的抑制作用,提示CI-914主要影响花生四烯酸(AA)环氧酶途径,而对脂氧酶途径影响较少。在大鼠血小板和中性白细胞CI-914能抑制TXA₂的生成,同时CI-914还可使白细胞6-keto-PGF_1a和血小板PGE₂的产生量显著增加,提示CI-914在这两种细胞引起了AA的转向合成。上述结果基本证实,CI-914在大鼠中性白细胞和血小板对TXA₂合成酶具有选择性抑制作用。     

电针刺激对大鼠渗出液前列腺素E_2和F_(2α)浓度及其比值的影响

本文应用放射免疫法测定了巴豆油诱发大鼠肉芽囊渗出液无细胞上清和炎性白细胞中PGE_2和PGF_2α含量,并探讨了电针刺激对PGE_2和PGF_2α含量及其比值变化的影响,证明电针刺激的抗渗出作用至少与电针刺激降低FGE_2/PGF_2α比值有关。     

磁场对雄性大鼠体内两种促性腺激素水平的影响

本文采用放射免疫测定法、研究磁场作用下雄性大鼠体内两种促性腺激素—FSH及ICSH水平的变化、以求探明磁场对垂体及生殖系统的生物学效应。结果表明:在旋磁作用下(表面静磁场为2000GS),雄性大鼠体内这两种激素的水平无明显改变,这为磁疗在临床使用上的安全性提供了一个理论根据。     

Immunochemical studies of turnip yellow mosaic virus--II. Localization of a viral epitope in the N-terminal residues of the coat protein

The N-terminal region of the coat protein of turnip yellow mosaic virus has been shown by immunochemical means to be present on the external surface of the virion. Seven synthetic peptides corresponding to overlapping regions of residues 1–12 of the coat protein have been prepared. The inhibitory activity of these peptides was measured by complement fixation tests, RIA and ELISA, using either antibodies directed to the depolymerized viral subunits or antibodies to the capsid. The activity of peptides varied markedly in different assays, illustrating the advantage of using several different immunochemical methods for the analysis of viral antigenic determinants.