静脉预注H1,H2受体阻滞药对减轻鱼精蛋白副作用的研究

将３０例ＡＳＤ、ＶＳＤ患者随机分为对照与预防用药两组，对比观察Ｈ１、Ｈ２受体阻滞药苯海拉明、西米替丁对减轻鱼精蛋白副作用的效果和应用鱼精蛋白后补体Ｃ３、Ｃ４、ＣＨ５０浓度变化。结果发现预防用药组血液动力学变化明显小于对照组，两组之间差异显著（Ｐ＜０．０１）。应用鱼精蛋白后Ｃ３、Ｃ４、ＣＨ５０均下降，与用药前相比差异显著（Ｐ＜０．０１）。提示鱼精蛋白中和肝素可引起补体激活、组胺释放，Ｈ１、Ｈ２受体阻滞药能够减轻鱼精蛋白引起的血压下降。     

Development of HPLC plasma assays for CAM 4515 and CAM 4750, two new nonpeptide tachykinin antagonists, and application to bioavailability studies

CAM 4515 and CAM 4750 are new nonpeptide tachykinin NK₁ receptor antagonists with different lipophilicities. Two separate, simple, and sensitive HPLC methods for the quantitation of these two compounds in plasma and the evaluation of their oral bioavailability in rats were developed and validated. Extraction of CAM 4515 from plasma involved protein precipitation with acetonitrile, while that for CAM 4750 involved a one-step liquid-liquid extraction with methylene chloride. The analytes in extracts were chromatographed on a C18 column using two different separation buffers, 47% 0.02 M sodium citrate (pH 3.5)-53% acetonitrile for CAM 4515 and 59% 0.02 M potassium phosphate dibasic (pH 7.0)-41% acetonitrile for CAM 4750, and both compounds were detected by fluorescence (excitation 278 nm; emission 342 nm). Stability profiles of both drugs at −20°C or room temperature in plasma and in reconstituted buffers were good. The limit of quantitation for both drugs was 5 ng ml⁻¹ with good linearity from 5 to 1000 ng ml⁻¹ using 100–200 μl of plasma. Excellent precision (relative standard deviation < 8.3%) and accuracy (relative error ± 9.2%) were observed for both CAM 4515 and CAM 4750. Oral bioavailability studies were conducted for each compound in rats receiving a p.o. dose of 20 mg kg⁻¹ and an i.v. dose of 5 mg kg⁻¹. The absolute oral bioavailability of CAM 4750 (80%) was estimated to be 40-fold greater than that of CAM 4515 (2%). The experimental results suggest that incorporation of a pyridine group into the structural backbone may greatly improve bioavailability.     

Does H2-receptor antagonist alter the renal function of cyclosporine-treated kidney grafts?

Histamine-type 2 antagonists (H₂-blockers) as represented by cimentidine have been shown to adversely affect renal allograft function, particularly when coadministered with cyclosporine, currently a major immunosuppressant. To determine whether or not a newer and more powerful H₂-blocker, famotidine, would produce similar adverse effects, we assessed seven cyclosporine-treated renal allograft recipients with regard to changes in their renal function on or off the H₂-blocker over a one-week period. Neither the administration nor withdrawal of famotidine (20–40 mg/day) resulted in any significant changes in serum creatine, BUN, urine output or cyclosporine trough levels, suggesting that famotidine can be safely administered as an H₂-blocker to cyclosporine-treated renal allograft recipients.     

Nerve growth factor and p75NGFR factor receptor mRNA change in rodent CNS following stress activation of the hypothalamo-pituitary-adrenocortical axis

The synthesis of nerve growth factor (NGF) by the hippocampus raises the possibility that NGF may play a role in the regulation of the hypothalamic-pituitary-adrenal axis (HPAA). Subchronic cold stress has been shown to activate the HPAA in a mild noninvasive manner, to stimulate serum glucocorticoid levels, and to perturb NGF binding in hippocampus and basal forebrain. One or repeated episodes of cold stress increased NGF mRNA levels in the hippocampus and p75^NGFR mRNA levels in the basal forebrain. These changes were not due to elevated serum glucocorticoid levels since treatment with exogenous corticosterone had no effect on NGF and p75^NGFR mRNA levels. Adrenalectomy did not prevent the stress induced increases in NGF and p75^NGFR mRNA. © 1993 Wiley-Liss, Inc.     

Raf-1 kinase,epidermal growth factor receptors,and mutant ras proteins in colonic carcinomas

Epidermal growth factor receptors (EGFR) andras mutations are known to play a significant role in controlling cell growth and tumor promotion. Both of them transmit mitogenic signals to the nucleus by activation of Raf-1 kinase. In this study, the expression of EGFR and mutant Ras proteins, and, for the first time, the expression, phosphorylation and kinase activity of Raf-1 kinase have been determined in paired samples of colorectal cancer and mucosa. The tumor and mucosa samples did not differ significantly with regard to Raf-1 kinase content and activity. A major difference between tumors and mucosa was found, however, in the phosphorylation of Raf-1. Most of the mucosa samples (13/20), but only 1/20 of the cancer samples, contained hyperphosphorylated Raf-1. EGFR were significantly (p=0.0025) decreased in the tumors. The decreased phosphorylation of Raf-1 in colonic carcinomas could be the result of activation of Raf-1 phosphatases or inactivation of kinases phosphorylating Raf-1. New forms of treatment based on EGFR overexpression do not seem to be suitable for the majority of colonic cancers.This work was supported by the state of Baden-Württemberg (Verbundforschungsprojekt: Aufklärung von Mechanismen der Tumorentstehung und Tumorabwehr).     

Nociceptin (Orphanin FQ) abolishes gestational and ovarian sex steroid-induced antinociception and induces hyperalgesia

Nociceptin (Orphanin FQ) is a newly discovered endogenous heptadecapeptide substrate for the opioid-receptor-like 1 receptor, a G protein coupled receptor that bears striking amino acid sequence homology to opiate receptors. In rats, intrathecal (i.t.) administration of nociceptin is without effect on basal thresholds for responsiveness to electric foot shock. However, during either late gestation or its hormonal simulation, when nociceptive thresholds are elevated by approximately 70%, i.t. nociceptin substantially attenuates jump thresholds in a dose-dependent fashion. This hypoalgesic effect of nociceptin is not limited to attenuating the gestational or sex steroid-induced increment in pain thresholds. Following the highest i.t. dose of nociceptin employed (20 nmol), the gestational or sex steroid-induced increment in jump thresholds is not only abolished but a significant hyperalgesia is observed. These results underscore the importance of the hormonal milieu to nociceptin hypoalgesic sensitivity. The potential contribution of spinal nociceptive pathways that utilize nociceptin to the etiology of extraordinary painful pregnancy and labor should not be ignored.     

重症肌无力中枢神经系统受损模型

目的近年研究结果表明，重症肌无力（ＭＧ）病变部位并不仅仅局限于神经肌接头（ＮＭＪ）处突触后膜烟碱型乙酰胆碱受体（ｎＡＣｈＲ），烟碱型乙酰胆碱受体抗体（ＡＣｈＲ－ａｂ）病理作用可能波及到中枢神经系统（ＣＮＳ）。因此，有必要建立模拟ＭＧ患者ＣＮＳ损害的动物模型，研究ＭＧ患者脑脊液中存在的ＡＣｈＲ－ａｂ引起ＣＮＳ损害的机制。方法从ＭＧ患者血中提取的ＡＣｈＲ－ａｂ经侧脑室穿刺注入到大鼠脑室系统，然后观察其症状和体征，以及用脑干听觉诱发电位仪（ＢＡＥＰ）检测鼠脑干听觉传导中枢功能。用免疫组化法（ＡＢＣ）研究ＡＣｈＲ－ａｂ与ＣＮＳ神经－ｎＡＣｈＲ之间免疫结合反应及其分布。结果大鼠除了出现脑干听觉传导中枢功能障碍外，还出现类似于ＭＧ动物模型表现的症状。免疫组化研究结果显示，神经－ｎＡＣｈＲ样阳性免疫反应广泛分布于ＣＮＳ许多部位。结论脑室内注入的ＡＣｈＲ－ａｂ与神经－ＡＣｈＲ结合引起ＣＮＳ功能障碍和出现ＭＧ动物模型样症状。我们首次建立的中枢受损的ＭＧ模型将有助于阐明ＡＣｈＲ－ａｂ引起中枢受损和ＣＮＳ下位运动神经元引起横纹肌收缩无力的机制。     

Studies of the antagonistic effect of BQ-123 on cerebral vasospasm induced by intracisternal injection of endothelin-1 and subarachnoid hemorrhage

Cerebralvasospasm(CVS)remainsoneofthemajorcausesofseriousoutcomeinpatientswithsubarachnoidhemorrhage(SAH);however,themechanismofwhichisstillnotwellunderstood.Sofaralargenumberofputativespasmogenshavebeenproposedandoneofwhichisendothelins(ETs).ETs,akindofverypotentendogenousvasoconstrictorsubstancesknown[1],hasthreeiso-forms:ET-1,2and3,andET-1isthemostpo-tentvasoconstrictorofthem.lnrecentstudies,ET-lhasbeenproposedasamediatorofCVSfol-lowingSAH[2-4j.TheavailabilityofETantagonistprovided…     

Inadequate Erythropoietin Response to Anaemia in HIV Patients: Relationship to Serum Levels of Tumour Necrosis Factor-Alpha, Interleukin-6 and Their Soluble receptors

Severe anaemia is a frequent complication in advanced HIV infection. In our study we investigated the interaction between cytokine network, HIV infection and erythropoietin (Epo) response with increasing anaemia levels. No correlations could be established between circulating tumour necrosis factor (TNF)-alpha and any of the examined parameters. However, a negative correlation was found between haemoglobin values and soluble TNF receptor levels (sTNF-R-I: r  = −0.54; P  < 0.001; sTNF-R II: r  = −0.47; P  < 0.001) as well as interleukin-6 levels ( r  = −0.29; P  < 0.001). In contrast, no significant increase in log[Epo], counterbalancing haemoglobin decline and paralleling the rise in sTNF receptors, was found. In patients classified as stage III, according to the Centers for Disease Control (CDC) classification, the erythropoietin response was significantly more impaired than in patients from CDC groups I and II ( P  < 0.001). The results of this study suggest that similar to its action in vitro , activation of the TNF/TNF-R system may impair erythropoietin production in HIV-associated anaemia. Due to the brief half-life of TNF-α, this activation is particularly reflected by elevations of soluble TNF receptor levels.     

Fas receptor expression on B-lineage cells

Mice homozygous for the lpr mutation have B and T cell defects and develop autoantibodies, suggesting that lpr plays a role in their genesis. The lpr defect has been identified as a mutation in the apoptosis-associated Fas receptor (FasR) gene. To begin to define the role of FasR in B cells, we have surveyed FasR expression on B-lineage cells from early progenitors in the bone marrow through their maturation in the periphery. Contrary to some reports, we found that FasR is expressed on B cells at all stages of their development and is highest on germinal center B cells. FasR is not expressed on lpr/lpr-derived cells. These data are consistent with the idea that lpr/lpr mice have an intrinsic B cell defect that may be manifested in developing as well as peripheral B cells. An unexpected finding is that B-1 (CD5) B cells do not constitutively express FasR: FasR becomes detectable on B-1 B cells only after activation.