不同日龄大鼠感染不同剂量内毒素对其血气、血糖的影响

目的:观察不同日龄大鼠感染不同剂量内毒素对血气、血糖的影响。方法:通过向健康7d(新生组,60只)、18d(幼鼠组,47只)Wistar大鼠腹腔注射不同浓度的内毒素,制作脓毒症模型,在0、2、4、6、24h5个时点(采血时尚存活的)每个时点8只,断头取混合动、静脉血观察其血气及血糖的动态变化。结果:新生鼠24h出现显著代谢性酸中毒、呼吸性硷中毒及低氧血症;而幼鼠组酸血症出现的时间较早,且程度较轻,两组差异显著,P<0.05;新生鼠血糖24h最低,而幼鼠组最低点在6h,且改变明显减轻,两组差异显著,P<0.05。结论:不同日龄的大鼠对不同剂量内毒素的反应不同,年龄越小早期反应越迟钝,后期损害越严重。     

荷电微孔滤膜的制备及其性能的初步研究

 本文报道一种由相转化法制备的荷电微孔滤膜及其制备和性能评价。采用的膜材料为聚酰胺和天然多糖。实验表明，该膜带正电荷，可以除去溶液中带负电荷的微量杂质，如细菌内在素和色素等。它属于一种新的过滤介质，在医药、纯水制备以及生物医学工程等方面有着广泛的应用前景。     

Development and Application of an Isolated Perfused Rat Liver Model to Study the Stimulation and Inhibition of Tumor Necrosis Factor-α Production ex Vivo

Purpose. To develop an isolated perfused rat liver (IPRL) model with low baseline levels of tumor necrosis factor (TNF)- in the outlet perfusate to study the effects of immunostimulants and immunosuppressants on the release of TNF- from this organ. Methods. Isolated rat livers were perfused with a buffer containing no albumin or three different bovine serum albumin (BSA) preparations. Using the no-albumin perfusate, the inhibitory effects of methylprednisolone (MP) on lipopolysaccharide (LPS)-stimulated release of TNF- were studied in livers isolated 1 or 5 h after the intravenous administration (5 mg/kg) of MP. The concentrations of TNF- in the outlet perfusates were measured using enzyme-linked immunosorbent assay. Results. In the absence of albumin, the perfusate levels of TNF- were close to zero. However, when the perfusate contained BSA, the TNF- levels in the perfusate reached as high as 1200 pg/ml at steady state. An injection of LPS into IPRLs perfused with a no-albumin perfusate resulted in mean (± SD) TNF- steady-state concentrations of 825 ± 125 pg/ml. The pretreatment of rats with MP before liver harvest attenuated the LPS-induced TNF- release in the livers. However, the attenuation was substantial (>60%) and was statistically significant only 5 h after pretreatment with MP. Conclusions. Perfusates containing BSA may result in nonphysiologically high levels of TNF-. An IPRL with a no-albumin perfusate is more suitable for studies of the stimulation and inhibition of TNF- production by this organ.     

Interleukin-8 secretion from monocytic cell lines for evaluation of the inflammatory potential of organic dust

The potential of organic dust to induce inflammation in vitro can be viewed as a crude measure of the total biologically active compounds in a dust sample. The purpose of this study was to further develop an in vitro screening method for evaluation of potential hazard related to low doses of dust exposure using two monocytic cell lines (U937 and THP-1). Dust was obtained from schools in Copenhagen. U937 and THP-1 cells were stimulated with dust for 24 h and interleukin-8 secretion was measured. The initial slopes of the dose-response curves were used to calculate the inflammatory potential, or potency factor (PF), of the samples. In characterization of the method, lipopolysaccharide from Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Salmonella enteritidis were tested together with three glucans, nickel sulfate (NiSO(4)), methyl methacrylate (MMA), formaldehyde, and four surfactants. The PF values of LPSs in both monocytic assays ranked as follows: S. enteritidis> E. coli>K. pneumoniae/P. aeruginosa. The PF values of NiSO(4), MMA, formaldehyde, and the surfactants were zero or below. Using the THP-1 cell line, the PF values of dust samples were 30 times higher than when using the U937 cell line, and 7 times higher than when using the lung epithelial cell line (A549). The high sensitivity of the THP-1 bioassay makes it potentially useful as a screening tool for hazard evaluation of dust from, e.g., the indoor environment.     

The effect of endotoxin administration on the secretory dynamics of oxytocin in follicular phase mares: relationship to stress axis hormones

The primary aim of this study was to define the secretory dynamics of oxytocin and vasopressin in pituitary venous effluent from ambulatory horses during acute endotoxaemia, a stimulus that may release both hormones. Our secondary aim was to investigate the role of oxytocin in regulating adrenocorticotropic hormone (ACTH) secretion by comparing oxytocin, vasopressin, corticotropin-releasing hormone (CRH) and ACTH secretory profiles during endotoxaemia and by monitoring the ACTH response to oxytocin administration. Pituitary venous blood was collected nonsurgically continuously and divided into 1-min segments from eight follicular phase mares. Four mares were sampled for 30 min before and 3.5 h after receiving an i.v. infusion of bacterial endotoxin (TOX). Four control mares were sampled for 2.5 h without infusion of TOX. Another three follicular phase mares were given 5 U of oxytocin to replicate the peak response to TOX and pituitary blood collected every 1 min for 10 min before and 15 min after injection. Endotoxin raised the secretion rates of all hormones measured. All hormones were released episodically throughout the experiment, with TOX increasing the amplitude of peaks in each hormone. Peaks in oxytocin and vasopressin were coincident in each treated mare. Similarly, ACTH peaks were coincident with peaks of oxytocin and vasopressin in each treated mare, and with peaks of CRH in three mares. However, oxytocin administration did not affect ACTH secretion. We conclude that during endotoxaemia in horses: (i) oxytocin and vasopressin are secreted synchronously; (ii) oxytocin is unlikely to be acting as an ACTH secretagogue since inducing peak oxytocin concentrations observed during TOX does not raise ACTH; and therefore (iii) the close relationship between oxytocin and ACTH secretion is circumstantial and due to the fact that oxytocin secretion is concurrent with that of vasopressin, a proven ACTH secretagogue in horses.     

特异性鲎试剂检测人参多糖注射液中的细菌内毒素

 目的：建立快速的人参多糖注射液细菌内毒素检查法。方法：用特异性鲎试剂对不同批号的人参多糖注射液分别进行干扰试验,考察确立人参多糖注射液内毒素检查法。结果：将人参多糖注射液稀释25倍利用特异性鲎试剂检测可消除干扰作用,结果准确可靠。结论：选用特异性鲎试剂,细菌内毒素检查法代替人参多糖注射液热原检查是可行的。     

Influence of lipopolysaccharide exposure on airway function and allergic responses in developing mice

Exposure to endotoxin has been associated with an exacerbation of asthmatic responses in humans and animal models. However, recent evidence suggests that microbial exposure in early life may protect from the development of asthma and atopy. In this study, we sought to evaluate the effects of lipopolysaccaride (LPS) on airway function in developing mice. In addition, we evaluated the influence of LPS on subsequent allergen sensitization and challenge. Under light anesthesia, 2-3-week-old Balb/c mice received a single intranasal instillation of LPS or sterile physiologic saline. Measurements of airway function were obtained in unrestrained animals, using whole-body plethysmography. Airway responsiveness was expressed in terms of % enhanced pause (Penh) increase from baseline to aerosolized methacholine (Mch). In additional studies, we assessed the functional and cellular responses to ovalbumin sensitization and challenge following prior exposure to LPS.We found that exposure to LPS induced transient airway hyperresponsiveness to Mch. These functional changes were associated with the recruitment of neutrophils and lymphocytes into the bronchoalveolar lavage (BAL) fluid. Airway responsiveness after allergen sensitization and challenge was decreased by prior exposure to LPS. The analysis of BAL cells and cytokines (interferon-gamma and interleukin-4) did not reveal alterations in the overall Th1/Th2 balance.Our findings suggest that LPS leads to airway hyperresponsiveness in developing mice, and may protect against the development of allergen-driven airway dysfunction.     

Influence of surgery and endotoxin-induced sepsis combined on natural killer cell activity, oxidative burst of granulocytes and antigen presentation capability of monocytes

BACKGROUND: Cell mediated immunity is affected in the course of sepsis and following surgical stress. The natural killer (NK) cells, the granulocytes and the monocytes constitute the immediate unspecific cell mediated immunity. We therefore investigated the effect of surgery- and endotoxin-induced sepsis on NK cells, granulocytes and monocytes in a two-hit model. METHODS: Three groups of 40 mice. Each group was divided into four groups of 10 mice. All the animals were anesthetized and subjected to either: laparotomy; treatment with Escherichia coli endotoxin i.p.; laparotomy followed 20 min later by endotoxin i.p.; or left untreated as a control group. In the first 40 mice the NK cell activity in the spleen and number of NK cells in the liver were measured, in the second the oxidative burst of granulocytes, and in the third the antigen presentation capacity of monocytes. RESULTS: Endotoxin stimulated the NK cell activity and up-regulated the antigen presentation capability on monocytes. In contrast, surgical stress reduced the NK cell activity, the number of NK cells and down-regulated the antigen presentation capability on monocytes. After surgery, followed by administration of endotoxin, the oxidative burst of granulocytes was stimulated while antigen presentation capability on monocytes was down-regulated. Endotoxin prevented or reverted the postoperative suppression of NK cell activity. CONCLUSION: Our two-hit model shows that some cell types of the unspecific immune system exhibit an excessive inflammatory response (NK cells, granulocytes) while specific functions of other cell types (monocytes) are simultaneously diminished. This diversity makes a potential therapeutic immunomodulation very complex as some cell types would need to be down-regulated while others need to be stimulated.     

用同体系模型动态比浊法定量测定血液透析浓缩液的细菌内毒素

目的授权应用已获专利的能有效消除供试品干扰的定量内毒素检查方法———同体系模型(专利号:03126794.7)动态比浊法定量检查血液透析酸性浓缩液(A液)中的细菌内毒素含量。方法对A液中定量添加标准内毒素进行干扰预试验,将A液稀释成30,40,50,60倍,定量添加标准内毒素,其回收率分别为76.12%,112.4%,173.6%,141.8%;从中筛选出最佳的稀释倍数为40倍,对3个批号(GH0504003,GH0504009,GH0504012)A液进行干扰试验,其回收率分别为116.7%,90.42%,113.8%。结果标准内毒素使用0.015 6,0.125,1.00 Eu/mL,将A液稀释成40倍,定量添加标准内毒素,回收率均在50%~200%之间,认为A液对动态比浊法无干扰作用,可用于A液供试品检查。结论应用同体系模型动态比浊法可以定量检测A液中的细菌内毒素。     

头孢替唑钠细菌内毒素检查法的研究

目的:建立头孢替唑钠细菌内毒素检查法。方法:用三个不同厂家生产的鲎试剂对头孢替唑钠进行干扰试验。结果:头孢替唑钠浓度为1．25mg/ml的稀释液不干扰细菌内毒素试验。结论:头孢替唑钠采用细菌内毒素检查法是可行的。