Protective effectiveness of an endotoxin-depleted pertussis vaccine

Pertussis vaccine depleted of endotoxin by the polymyxin-Sepharose affinity chromatography method was tested for toxic activity and protective effectiveness in mice. Preparations containing 1000-fold and 1 000 O00-fold less endotoxin fulfilled the established experimental criteria for freedom from toxicity. A fourfold concentrate of the former demonstrated a protection rate only 10% less than that of standard, untreated pertussis vaccine.     

Splanchnic ischaemia and its role in multiple organ failure

Multiple organ failure remains the leading cause of death in the intensive care unit. Increasing numbers of investigators have focused their attention on the role of gastrointestinal tract in the pathogenesis of this syndrome. Their data indicate that inadequate gut perfusion leads to a measurable imbalance between oxygen delivery and the needs of the tissues, i.e., ischaemia. Gut ischaemia of sufficient duration impairs gastrointestinal tract barrier function, facilitating the passage of enteric bacterial endotoxin into the circulation. It has been hypothesized that production of tumor necrosis factor α, and other biologic mediators by endotoxin–stimulated macrophages, triggers a generalized and uncontrolled inflammatory response that ultimately leads to multiple organ failure.
Preliminary evidence suggests that survival can be improved significantly if gut ischaemia is promptly identifed and aggressively treated by administration of fluids and inotropic drugs, using gastric intramucosal pH as the therapeutic endpoint. Future studies are needed to determine whether additional treatment modalities can improve outcome once the inflammatory response has fully developed.     

Human monocyte interactions with non-enzymatically glycated collagen

Summary We have previously shown that receptors for advanced glycation end products are expressed on activated human monocytes. We now report that activated human monocytes exhibit increased adhesion to non-enzymatically glycated collagen substrates (+32%±1, p<0.001), and the increased adhesion can be competitively inhibited with non-enzymatically glycated albumin. Non-activated monocytes, which do not express receptors for advanced glycation end products, exhibit decreased adhesion (-16%±1, p<0.001). Similar results were observed with substrates of fibronectin and endothelial cell matrix proteins. As the presence of glycation adducts on collagen interferes with the normal binding of monocytes/macrophages, one possible role for advanced glycation adduct receptors on activated monocytes is to counterbalance such decreased adherence. Overcompensation for long periods of time may lead to pathological changes. Additionally, such receptors may play a role in monocyte-mediated remodelling of glycated matrix proteins, as we have observed increased degradation of nonenzymatically glycated collagen substrates by activated human monocytes at 2 h (+52%±11, p=0.01), 3 h(+49% ±10, p=0.01), and 4 h (+36%±6, p<0.01) after adding activated monocytes to ¹²⁵I-labelled substrates.     

美托洛尔治疗高血压病的疗效及其耐受性

原发性高血压患者425例(男252,女173;年龄60±s12a)采用美托洛尔100mg,po,每晨1次,4wk为一个疗程。总有效率82.4％,治疗2wk后血压继续下降,心率并不继续减慢。不良反应主要为心率减慢后的症状及神经系症状,停药率6.4％。60a以上的患者总有效率及停药率与中、青年患者无明显区别。故美托洛尔同样适用于老年人。     

Anti-inflammatory,analgesic, antipyretic and related properties of meloxicam,a new non-steroidal anti-inflammatory agent with favourable gastrointestinal tolerance

The anti-inflammatory, analgesic and antipyretic properties of the new non-steroidal anti-inflammatory agent, meloxicam, were investigated in a variety of animal models and compared with the properties of piroxicam, diclofenac, indomethacin and several other NSAIDs.With respect to the total effect of a single oral dose, the anti-exudative effect of meloxicam on carrageenaninduced oedema in the rat exceeded that of all the NSAIDs included in the comparison. Additionally, meloxicam showed the greatest potency of all the compounds examined with respect to adjuvant-induced arthritis in the rat, the granuloma pouch model and the cotton pellet test in the rat. Unlike indomethacin, in the carrageenan pleurisy model in the rat, meloxicam caused both a dose-dependent reduction in exudate volume and also inhibition of leucocyte migration.Meloxicam showed a strong and lasting effect on inflammatory pain in the rat. Like other NSAIDs, but unlike dipyrone, meloxicam had no effect in the hot plate and tail clamp tests, which are used to identify weak central analgesic effects. Unlike dipyrone and like indomethacin, meloxicam had no effect in a model of visceral distention pain.In common with other NSAIDs, meloxicam had no influence on the body temperature of normothermic rats in the anti-inflammatory dose range, but did reduce yeastinduced fever in the rat in a dose-dependent manner. Like piroxicam, meloxicam had a uricosuric effect on rats treated with oxonic acid.Low-dose meloxicam inhibited both bradykinin-induced and PAF-induced bronchospasm in the guinea-pig, but had no effect on acetylcholine-induced bronchospasm.Piroxicam had greater ulcerogenic effects in the rat stomach than meloxicam.The therapeutic range of meloxicam in the rat, with regard to inhibition of adjuvant arthritis, was several times greater than that of piroxicam, indomethacin, diclofenac and naproxen.     

口服耐受的机制及其在自身免疫病治疗中的应用

口服耐受是指口服蛋白引起的一种免疫低反应状态。自Ｗｅｌ１ｓｌ９１１年首先报道这种现象以来，口服耐受引起了广泛关注，大量研究者发现给动物饲服蛋白质或绵羊红细胞后，再次消化道外免疫时，动物对这些抗原不再具有良好的反应性，而对其它抗原的反应正常［１］。免疫...     

Abortive Proliferation of Rare T Cells Induced by Direct or Indirect Antigen Presentation by Rare B Cells In Vivo

Antigen-specific B cells are implicated as antigen-presenting cells in memory and tolerance responses because they capture antigens efficiently and localize to T cell zones after antigen capture. It has not been possible, however, to visualize the effect of specific B cells on specific CD4⁺ helper T cells under physiological conditions. We demonstrate here that rare T cells are activated in vivo by minute quantities of antigen captured by antigen-specific B cells. Antigen-activated B cells are helped under these conditions, whereas antigen-tolerant B cells are killed. The T cells proliferate and then disappear regardless of whether the B cells are activated or tolerant. We show genetically that T cell activation, proliferation, and disappearance can be mediated either by transfer of antigen from antigen-specific B cells to endogenous antigen-presenting cells or by direct B–T cell interactions. These results identify a novel antigen presentation route, and demonstrate that B cell presentation of antigen has profound effects on T cell fate that could not be predicted from in vitro studies.     

Acute tolerance to ethanol using drug discrimination and open-field procedures in rats

This study examined the phenomenon of acute tolerance to ethanol (ETOH) using drug discrimination learning (DDL), and open-field (OF) procedures. In DDL, rats were trained to discriminate between ETOH (1.2 g/kg) and saline. Doses of ETOH lower (0.6 and 0.9 g/kg), or higher (1.8 and 2.4 g/kg) than the training dose were tested to examine possible influence of ETOH pretreatment doses on the expression of acute tolerance. To assess concentrations of ETOH in the organism, a rebreathed air procedure was used. Equal concentrations after different ETOH doses were achieved by postponing the tests until sufficient time had elapsed. Only doses of ETOH higher than the training dose produced acute tolerance in the DDL procedure. For the response-time data no acute tolerance was observed. In the OF experiment, the occurrence of acute tolerance was examined for different spontaneous behaviours in drug-naive animals. At equal ETOH concentrations, the group examined during the descending phase of intoxication (1.8 g/kg, 60 min post-injection), reared significantly more than the group tested during the ascending phase (1.5 g/kg, 10 min post-injection). Other OF behaviours did not differ significantly between the two time intervals. Thus, it is suggested that acute tolerance is seen both in ETOH naive and in ETOH pre-exposed rats. However, in DDL acute tolerance was observed only when doses higher than the training dose of ETOH were evaluated.     

自发免疫耐受大鼠移植肝内调节性T细胞的生物学特性

目的研究大鼠肝移植后自发免疫耐受的形成与移植肝内CD4~ CD25~ 调节性T细胞(Tr细胞)的关系。方法按供、受者不同将实验分为3组。急性排斥组:DA大鼠为供者,LEW大鼠为受者;自发耐受组:LEW大鼠为供者,DA大鼠为受者;同基因组:供、受者均为DA大鼠。各组均建立大鼠原位肝移植模型。分别在肝移植术后4、7、14、30和90 d时采用密度梯度离心法分离移植肝内淋巴细胞,免疫磁珠分离(MACS)法分选出CD4~ CD25~ Tr细胞;用流式细胞术(FCM)检测细胞纯度,同时分析CD4~ CD25~ Tr细胞比例的变化;体外细胞增殖试验研究CD4~ CD25~ Tr细胞对CD4~ CD25~-T细胞的免疫抑制作用。结果肝移植早期,急性排斥组和自发耐受组移植肝内CD4~ CD25~ Tr细胞比例均明显增加,其中急性排斥组增加更为明显;移植后4 d左右,两组CD4~ CD25~ Tr细胞比例开始下降,急性排斥组的下降幅度较大;移植后30 d,自发耐受组受者的移植肝内CD4~ CD25~ Tr细胞比例达到第2次高峰,约在移植后90 d时下降至正常生理水平。移植后7 d左右,急性排斥组受者均因发生排斥反应而死亡,而自发耐受组受者均存活。此外,CD4~ CD25~ Tr细胞能有效抑制CD4~ CD25~-T细胞的增殖。结论CD4~ CD25~ Tr细胞是一种具有特异免疫调节功能的T细胞亚群,其主动的免疫抑制功能可能是诱导大鼠肝移植自发免疫耐受的机制之一。     

Endotoxin administration stimulates cerebral catecholamine release in freely moving rats as assessed by microdialysis

In vivo microdialysis was used to measure changes in extracellular concentrations of catecholamines and indolamines in freely moving rats in response to administration of endotoxin (lipopolysaccharide, LPS). Dialysis probes were placed stereotaxically in either the medial hypothalamus or the medial prefrontal cortex. We used a repeated-measures design in which each rat received LPS or saline, and each subject was retested with the other treatment one week later. With the dialysis probes in the medial hypothalamus, intraperitoneal (ip) administration of LPS (5 μg) increased dialysate concentrations of norepinephrine (NE, 187%), dopamine (DA, 119%), and all their measured catabolites, except normetanephrine. Dialysate concentrations of NE and DA were elevated significantly in the fourth or fifth (20 min) collection period with a peak response at around 2 hr. They returned to baseline by about 4 hr. When the dialysis probes were placed in the medial prefrontal cortex, the same dose of LPS also elevated dialysate concentrations of NE and DA, but the increases were much smaller (ca. 20%). However, a dose of 100 μg LPS increased dialysate concentrations of NE and DA from the medial prefrontal cortex to an extent comparable to that of the 5 μg dose in the hypothalamus, and the response was more prolonged. Dialysate concentrations of serotonin could not be measured reliably, but those of its catabolite, 5-hydroxyindoleacetic acid (5-HIAA), were also elevated in both regions. The peak of 5-HIAA occurred at around 4 hr. Pretreatment of the rats with indomethacin (10 mg/kg ip) completely prevented the changes due to 100 μg LPS in the medial prefrontal cortex. These results support earlier neurochemical data suggesting that LPS stimulates the release of both DA and NE in the brain, and probably also release of serotonin. © 1995 Wiley-Liss, Inc.