RESPONSIVENESS AND SENSITIVITY TO CHOLINERGIC AGONISTS AND ANTAGONISTS IN BOVINE ISOLATED BRONCHIAL MUSCLE

1. Airways derived from different levels of the lung exhibit a difference in the reactivity and sensitivity to agonists. We have evaluated the effect of acetylcholine and cholinergic selective (pirenzepine, gallamine and 4-dipherylacetoxymethyl piperidine [4-DAMP]) and non-selective (atropine) antagonists on bovine proximal and distal smooth muscle preparations. 2. The distal preparations are more sensitive to acetylcholine than proximal bronchi. The relaxant effect of three selective antagonists on the distal and proximal tissues was the same when the results for each drug were compared. 3. Atropine and 4-DAMP were more potent than pirenzepine and gallamine in relaxing both proximal and distal bovine smooth muscle preparations. 4. These data suggest that the muscarinic sites on the smooth muscle of bovine airways are of the M3 subtype.     

淋巴细胞β受体与放射配基结合所需孵育时间的确定

介绍理论运算和实验测量相结合，确定淋巴细胞膜碎片β受体与标记配基结合所需平衡时间的方法。结果表明：二种方法所得平衡时间基本一致。多点法时平衡时间需25-30min；单点法时需5-7min。     

FasL的表达在结直肠癌免疫逃逸中的意义

目的研究结直肠癌中Fas配体（FasL）的表达及其在结直肠癌免疫逃逸中的意义。方法采用免疫组织化学染色法，检测80例结直肠癌组织中FasL表达及肿瘤浸润淋巴细胞（TIL）的数量。应用原位杂交法，检测80例结直肠癌组织连续切片的FasL的。RNA的表达。采用脱氧核糖核酸末端转移酶介导的缺口末端标记技术（TUNEL），对80例结直肠癌组织中凋亡的TIL及肿瘤细胞进行观察。结果80例结直肠癌组织FasL表达程度不等，不论是在同一组织切片不同部位或两组织切片间相比，FasL表达程度和范围都不均匀。FasL的mRNA的表达部位与FasL蛋白的表达部位相对应。FasL表达程度高的组织的TIL计数低于FasL表达低的组织（P〈0．05），同时其TIL凋亡指数高于FasL表达低的组织，而结直肠癌细胞的凋亡指数低于FasL表达程度低的组织（P〈0．01），TIL凋亡指数与胃癌细胞的凋亡指数呈负相关（r=-0．631，P〈0．01）。结论全占直肠癌细胞可通过表达FasL，诱导TIL发生凋亡，反击机体免疫系统，这可能是结直肠癌免疫逃避的重要机制之一。     

Ascorbic acid (vitamin C) modulates the mutagenic effects produced by an alkylating agent in vivo

Recent reports suggest that ascorbic acid (vitamin C) inhibits tumorigenesis as well as exerts a protective effect against mutagenesis in vitro; however, there is no information on its ability to affect gene mutations induced in vivo. In this study, we have investigated the antimutagenic effects of ascorbic acid on the frequency of 6-thioguanine-resistant (6-TGr) T-lymphocytes produced in Fischer 344 rats dosed with the direct-acting alkylating agent, N-ethyl-N-nitrosourea (ENU). The freqeuncy of 6-TG^r T-lymphocytes from the spleen measured five weeks after ENU treatment indicated that ENU produced a substantial mutagenic response. Pretreatment and/or post-treatment of rats with ascorbic acid administered in the drinking water appeared to inhibit the response, but the inhibition was statistically significant only when data from the various dosing schedules were pooled. In addition, there was no clear dose-dependency to the inhibitory effect of ascorbic acid. To further evaluate the time effects of the vitamin supplement on ENU mutagenicity, rats were exposed to the mutagen together with ascorbic acid, which was given continuously for the entire duration of the experiment. At specific times after ENU treatment, the frequency of 6-TG^r T-cells was determined in lymphocytes isolated from the spleen and the thymus. Time-dependent increases in the frequency of 6-TG^r T-cells were observed with ENU treatment; ascorbic acid significantly reduced the ENU-mediated mutagenic responses, most dramatically in the spleen at weeks 6 and 8 (P < 0.0001), and to a lesser extent in the thymus (P < 0.01 at week 6 and P < 0.006 at week 8). Our data suggest that ascorbic acid intake affects the in vivo mutagenicity of ENU, a direct-acting mutagen/carcinogen, and that the reported inhibitory effects of the antioxidant on carcinogenesis may be partially mediated by its effects on mutagenesis. Although it is difficult to extrapolate from rodent studies to humans, the results presented suggest an explanation for epidemiological data that link vitamin C ingestion with decreased cancer risk. © 1994 Wiley-Liss, Inc.     

CO中毒致迟发性脑病大鼠脑内CD4+T淋巴细胞浸润及神经胶质酸性蛋白的表达

目的观察CO中毒致迟发性脑病（DNS）大鼠脑内CD4^＋T淋巴细胞浸润以及神经胶质酸性蛋白（GFAP）的表达情况，探讨CO中毒致DNS的病理过程。方法25只SD雄性大鼠随机分为对照组、染毒后3、7、10、20d组，每组5只。采用HE和免疫组织化学染色方法，观察染毒后各时间点大鼠脑内病理形态学变化，及CD4^＋T淋巴细胞浸润和GFAP的表达情况。结果HE染色结果显示：各染毒组在大脑皮层及海马均出现神经细胞不同程度的变性、坏死，染毒后7d组最重。免疫组织化学染色结果显示：对照组无CD4^＋T淋巴细胞浸润，有少量GFAP表达；各染毒组不同脑区CD4^＋T淋巴细胞、GFAP均有不同程度的浸润和表达。CD4^＋T淋巴细胞染毒后3d开始浸润，7d达峰值，两者在数量上差异有统计学意义（P〈0．01）。各组染毒后GFAP均有大量表达，随染毒时间延长表达数量呈上升趋势。结论CD4^＋T淋巴细胞可能参与了CO中毒致DNS的免疫病理过程，GFAP阳性细胞对CO中毒引发的DNS可能具有保护作用。     

维A酸对T淋巴细胞作用的研究进展

维A酸类药物广泛用于治疗各类皮肤病，且其适应证还在不断扩大。近年来越来越多的证据表明，维A酸具有免疫调节作用。首先，维A酸与皮肤免疫有密不可分的联系，其次，维A酸对机体T淋巴细胞的增殖、凋亡、趋化以及Th1／Th2细胞的极化都产生明显及确实的作用，但是维A酸发挥药理学作用涉及的蛋白调控、细胞因子分泌及信号传导的精确机制目前尚不清楚。     

Influence of impaired T- and B-cell compartments on efficacy of IVIg in dysimmune neuropathies

Autoimmune mechanisms are postulated to play a role in the development and progression of dysimmune neuropathies (DN). We investigated the relation between lymphocyte number and marker expression, and disease activity in 20 patients with DN under intravenous immunoglobulins (IVIg) treatment. B- and T-lymphocyte markers were studied by flow cytometry of the expression of CD5, CD25, CD23 and CD38 markers on B cells and of CD3, CD4 and CD8 markers, respectively. These parameters were compared with those obtained from matched healthy volunteers. The proportions of CD38+ B cells were higher in patients compared with those of controls. Proportions of activated CD4+ and CD8+ T cells were comparable in peripheral blood mononuclear cells of patients and controls, but a significant reduction of the absolute numbers of CD3+, CD4+ and CD8+ cells were observed in DN patients. The percentages of CD25+ memory T cells were instead significantly increased in DN patients. Lastly, T-cell reduction and the CD19/CD38 ratio over total B (CD19+) cells directly correlated with a poor response to IVIg therapy. In DN, whereas T-cell number is reduced, activated T and B cells are increased, thus suggesting an intrinsic defect of the immune response.     

Fluidity state of lymphocyte plasma membrane in malignant hyperthermia susceptible pigs and humans

Recent studies suggest that abnormalities occur at the lipid level in malignant hyperthermia susceptible humans and pigs. To test this hypothesis, we first investigated the physical state of plasma membranes of lymphocytes isolated from normal and malignant hyperthermia susceptible swine. In halothane-challenged pigs, malignant hyperthermia susceptibility was also assessed by ryanodine binding assay on purified sarcoplasmic reticulum membranes. The results clearly show that plasma membrane of lymphocytes from malignant hyperthermic pigs are significantly more fluid than controls. We then attempted to apply the same methodology to lymphocytes prepared from human patients previously diagnosed by the halothane and caffeine contracture test. In that case, there was no clear relationship between malignant hyperthermia susceptibility and the fluidity state of lymphocyte plasma membranes.     

Characteristics of antibody responses induced in mice by protein allergens

Whereas many foreign proteins are immunogenic, only a proportion is also allergenic, having the capacity to induce the quality of immune response necessary to support the production of IgE antibody. We have demonstrated previously that intraperitoneal administration to mice of proteins such as ovalbumin (OVA) or the industrial enzyme A. oryzae lipase, which possess significant allergenic potential, stimulates the production of both IgG and IgE antibody. Identical exposure to bovine serum albumin (BSA), a protein with limited potential to cause immediate respiratory or gastrointestinal hypersensitivity reactions, induced IgG responses only. In the current investigations, the quality of immune responses induced following exposure to these proteins via mucosal tissue (intranasal) has been compared with those provoked following administration via a non-mucosal (intraperitoneal) route of exposure. Intranasal or intraperitoneal administration of BSA, OVA or A. oryzae lipase elicited in each case vigorous IgG and IgG1 antibody responses. For all three proteins, at every concentration tested, and via both routes of exposure, IgG1 antibody titres paralleled closely IgG titres. However, the three materials displayed a differential potential to provoke IgE responses and this correlated with their known allergenic potential in humans. Thus, OVA and A. oryzae lipase stimulated strong IgE antibody responses, whereas BSA provoked low titre IgE only at the highest concentration tested (5% administered intraperitoneally). The quality of induced responses was not affected by the route of exposure. It would appear, therefore, that the stimulation of IgG and IgG1 antibody responses is a reflection of protein immunogenicity whereas protein allergenicity is associated with the induction of strong IgE responses.