Comparative toxicity studies between bacterial lipopolysaccharide (endotoxin) and N-formyl methionyl peptide as factors in the pathogenesis of byssinosis

Comparative in vivo and in vitro studies were made on bacterial lipopolysaccharide (LPS) and the chemotactic peptide NF-Met-Leu-Phe with a view toward studying their possible role in the pathophysiology of byssinosis. In contrast to LPS, chemotactic peptides did not cause Limulus amebocyte lysate gelation, nor did they induce the release of endogenous pyrogen. Inhalation of LPS caused a peripheral leukocytosis in rabbits 30 min after aerosol administration, whereas peptide inhalation caused a significant leukopenia in the same period. Cellular analysis of guinea pig bronchial lavages after LPS aerosol challenge revealed immediate decreases in all cell types, with subsequent, large increases of macrophages and granulocytes 4-24 h after aerosolization. Inhalation challenge with NF-Met-Leu-Phe induced no significant cellular changes. It was concluded that it is unlikely that these microbial products could be confused with each other when administered in pure form by the inhalation route.     

Drug interaction effects on antitumour drugs (X): exacerbation of cisplatin lethality by bacterial lipopolysaccharide in mice

To determine whether bacterial endotoxin (lipopolysaccharide, LPS from Escherichia coli) could modulate the lethality of cisplatin (CDDP) in mice, animals were treated with LPS (1 mg/kg, intraperitoneally) 24 hr and 1 hr before administration of cisplatin. A 1.6-fold increase in 8-day cumulative mortality was observed in LPS-treated mice compared to the mortality of those injected with saline before CDDP administration. The duration of previous exposure time to LPS appeared to be an important determinant of the potentiating effect, as many more mice died after 24 hr pretreatment than after 1 hr. Because renal toxicity remains a serious limitation to the effective use of CDDP, we determined whether LPS could also enhance CDDP-induced renal injury. CDDP markedly induces an increase in blood urea nitrogen (BUN) levels in LPS-treated mice. Treatment with LPS did not affect urinary excretion or renal tissue levels of total platinum, or the plasma pharmacokinetics of free and total platinum. Despite the potentiating effect of LPS on CDDP-induced lethality, it appeared that LPS can provide some enhancement of kidney function, because pretreatment of LPS enhanced an increase in BUN values.     

Protection against the toxicity of microcystin-LR and cylindrospermopsin in Artemia salina and Daphnia spp. by pre-treatment with cyanobacterial lipopolysaccharide (LPS)

Purified cyanobacterial lipopolysaccharide (LPS) was not acutely toxic to three aquatic invertebrates (Artemia salina, Daphnia magna and Daphnia galeata) in immersion trials. However, pre-exposure (24 h) to 2 ng mL⁻¹ LPS increased the LC₅₀ of microcystin-LR significantly in all 3 species. Similar results were observed with A. salina pre-treated with the same concentration of cyanobacterial LPS and subsequently exposed to cylindrospermopsin, increasing the LC₅₀ by 8. The findings indicate the need to include exposures to defined combinations of cyanotoxins, and in defined sequences, to understand the contributions of individual cyanotoxins in accounting for cyanobacterial toxicity to invertebrates in natural aquatic environments.     

注射用头孢哌酮钠舒巴坦钠(2:1)细菌内毒素检查法建立的方法学研究

目的 研究注射用头孢哌酮钠舒巴坦钠（2：1）的细菌内毒紊检查方法。方法 对照《中国药典2000年版》二部附录Ⅺ XF试验方法,采用不同厂家、不同批号的鲎试剂,通过干扰实验来确定注射用头孢哌酮钠舒巴坦钠（2：1）的有效稀释浓度.结果 注射用头孢哌酮钠舒巴坦钠（2：1）稀释成1．25mg／ml供试品液后,用0．125EU／ml的鲎试剂,对细菌内毒素检查无干扰。结论 注射用头孢哌酮钠舒巴坦钠（2：1）可以通过细菌内毒素检查法来控制其细菌内毒素含量。     

Responses to endotoxin of mice bearing the Lewis lung (3LL) carcinoma

We examined factors which could be responsible for altered sensitivity to endotoxin in tumor bearing mice in order to gain a greater insight into the mechanisms responsible for the toxic effects of the substance. C57BL/6 mice engrafted with 2 × 10⁵ Lewis lung carcinoma cells were injected with 300 μg Salmonella typhosa endotoxin 3,7 and 14 days after tumor cell implantation. A biphasic pattern of mortality was noted when 23 of 35, 1 of 20, and 33 of 34 mice died within 48 hr of injection with endotoxin on days 3, 7 and 14, respectively. Only 1 of 30 normal mice died after injection with this dose of endotoxin. Intestinal penetration by microbial substances did not explain the biphasic sensitivity to endotoxin. Sensitivity to endotoxin seen at day 14 could be associated with tumour mass, but this association would not explain sensitivity to endotoxin at day 3. Regression of tumour growth and decreased tumor-induced mortality was observed in mice injected with 300 μg of endotoxin 7 days after tumor implantation. Larger doses of endotoxin (400–700 μg) had a better therapeutic value but at the expense of increased endotoxin-induced mortality.     

Effects of diesel exhaust on lung inflammation related to bacterial endotoxin in mice

We have previously shown that intratracheal instillation of diesel exhaust particles enhances lung inflammation and lung expression of proinflammatory cytokines and chemokines related to bacterial endotoxin (lipopolysaccharide) in mice. The present study was designed to elucidate the effects of inhalation of diesel exhaust on lung inflammation related to lipopolysaccharide. ICR mice were exposed for 12 hr to clean air or diesel exhaust at a soot concentration of 0.3, 1.0, or 3.0 mg/m(3) after intratracheal challenge with 125 microg/kg of lipopolysaccharide. Lung inflammation and lung expression of proinflammatory chemokines such as macrophage chemoattractant protein-1 and keratinocyte chemoattractant were evaluated 24 hr after intratracheal administration. Diesel exhaust inhalation decreased lipopolysaccharide-elicited inflammatory cell recruitment into the bronchoalveolar lavage fluid as compared with clean air inhalation. Histological study demonstrated that exposure to diesel exhaust did not affect lipopolysaccharide-enhanced neutrophil recruitment into the lung parenchyma. Lipopolysaccharide instillation elevated lung expression of macrophage chemoattractant protein-1 and keratinocyte chemoattractant under clean air or diesel exhaust inhalation. However, diesel exhaust exposure did not influence but rather did suppress these levels in the presence of lipopolysaccharide. These results suggest that short-term exposure to diesel exhaust did not exacerbate lung inflammation related to bacterial endotoxin.     

Anaphylactic reactions to endotoxin in guinea-pig tissues: relationship to endotoxin toxicity.

1 A lipopolysaccharide extract of Escherichia coli 026:B6 cells (026:B6(B) endotoxin) was shown to be toxic to normal adult guinea-pigs. 2 The agent had no action on isolated preparations of ileum and heart taken from normal adult guinea-pigs. 3 Ileal segments from animals actively immunized against 026:B6(B) endotoxin showed dose-dependent contractions when exposed to endotoxin. Desensitization phenomena were demonstrated. 4 Reactivity of 026:B6(B) endotoxin was transferred to isolated preparations of ileum and heart from normal animals by passive transfer of immune serum. 5 Tissue responses to 026:B6(B) were associated with release of ileal spasmogen into the bath medium. Mepyramine blocked the effects of this spasmogen at bath concentrations which caused little change in ileal responses to carbachol. 6 It is concluded that E. coli endotoxin can elicit anaphylactic reactions, and that this process may potentiate endotoxin toxicity in sensitized animals. However, endotoxin toxicity in guinea-pigs does not appear to depend on this kind of allergic process.     

多西环素减轻小鼠内毒素性急性肺损伤的作用及机制研究

目的：探讨多西环素对内毒素性急性肺损伤的影响及机制。方法：将昆明小鼠随机分为：生理盐水对照组、多西环素组、内毒素脂多糖（LPS）急性肺损伤模型组及多西环素干预组。注射LPS24h后处死动物,行支气管肺泡灌洗（BALF）,计数灌洗液中白细胞数量及测定总蛋白含量。用ELISA分别测定肺组织匀浆上清液中TNF-a、基质金属蛋白酶-9（MMP-9）和金属蛋白酶组织抑制剂-1（TIMP-1）的含量。同时取肺组织进行病理学观察,测定肺组织湿/干重比值。结果：多西环素显著减少LPS所致BALF中白细胞数量、总蛋白浓度和肺组织湿/干重比值（P〈0.01）。多西环素能降低肺组织匀浆上清液中TNF-a和MMP-9含量（P〈0.01）,轻度上调TIMP-1的含量。多西环素能显著减轻LPS所致肺组织出血、肺水肿及炎性细胞浸润等肺损伤改变。结论：多西环素可减轻LPS所致急性肺损伤,其机制可能与抑制TNF-α等促炎因子释放及下调MMP-9/TIMP-1比值有关。     

Baicalin inhibits macrophage activation by lipopolysaccharide and protects mice from endotoxin shock

Baicalin (BA) exhibits anti-inflammatory effect in vivo and in vitro and is used to treat inflammatory diseases. Here, we report that BA inhibits the activation of macrophage and protects mice from macrophage-mediated endotoxin shock. The experiments in vitro showed BA suppressed the increased generation of nitric oxide (NO) and expression of inducible nitric oxide synthase (iNOS) induced by LPS or Interferon-gamma (IFN-gamma) without directly affecting iNOS activity in RAW264.7 cells and peritoneal macrophages. Similarly, BA inhibited the production of reactive oxidative species (ROS), whereas augmented the level of intracellular superoxide dismutase (SOD). Moreover, BA inhibited the production of inflammatory mediators including tumor necrosis factor (TNF)-alpha, endothelin (ET)-1 and thromboxane A2 (TXA2) induced by lipopolysaccharide (LPS) in RAW264.7 cells. In animal model, BA protected mice from endotoxin shock induced by d-galactosamine (D-GalN)/LPS possibly through inhibiting the production of cytokine and NO. Collectively, BA inhibited the production of inflammatory mediators by macrophage and may be a potential target for treatment of macrophage-mediated diseases.     

肌苷注射液的细菌内毒素检测

目的建立肌苷注射液的细菌内毒素检查法。方法参照《中国药典》2000年版二部附录细菌内毒素检查法进行试验。结果肌苷注射液在稀释至1.0mg/ml时可完全排除干扰作用。结论以细菌内毒素检查法替代热原检查法控制肌苷注射液的质量是可行的。     

细菌内毒素检查法检查多索茶碱注射液的热原

目的：多索茶碱注射液热源的检查。方法：细菌内毒素检查法。结果：经过实验检测均为阳性。结论：细菌内毒素检查法可用于多索茶碱注射液热源的检查。     

凝胶法检查甘露醇注射液细菌内毒素的应用

目的 :建立甘露醇注射液细菌内毒素检查的方法(凝胶法 ) ,以控制药品质量 ,减少临床热原反应的发生。方法 :按中国药典检测法 ,系统考察甘露醇注射液对鲎试剂与细菌内毒素凝集反应的干扰。结果 :确定甘露醇注射液细菌内毒限值为 5 0 0EU·L-1,凝胶法最佳检测条件为 :供试品 1∶8稀释 ,鲎试剂灵敏度 (λ) =6EU·L-1;供试品 (冷藏 ) 1∶4稀释 ,鲎试剂灵敏度 (λ) ) =12 5EU·L-1。结论 :应用凝胶法检测甘露醇注射液细菌内毒素 ,结果准确、重现性好。可替代家兔法用于甘露醇注射液的热原检查。     

N-acetylcysteine abrogates acute lung injury induced by endotoxin

1. Acute lung injury (ALI) or acute respiratory distress syndrome is a serious clinical problem with high mortality. N-Acetylcysteine (NAC) is an anti-oxidant and a free radical scavenger. It has been reported recently that NAC ameliorates organ damage induced by endotoxin (lipopolysaccharide; LPS) in conscious rats. The present study was designed to evaluate the effects of NAC on LPS-induced ALI and other changes in anaesthetized rats. 2. Sprague-Dawley rats were anaesthetized with pentobarbital (40 mg/kg, i.p.). Endotracheal intubation was performed to provide artificial ventilation. Arterial pressure and heart rate were monitored. The extent of ALI was evaluated with the lung weight (LW)/bodyweight ratio, LW gain, exhaled nitric oxide (NO) and protein concentration in bronchoalveolar lavage (PCBAL). Haematocrit, white blood cells, plasma nitrate/nitrite, methyl guanidine (MG), tumour necrosis factor (TNF)-alpha and interleukin (IL)-1b were measured. Pathological changes in the lung were examined and evaluated. 3. Endotoxaemia was produced by injection of 10 mg/kg, i.v., LPS (Escherichia coli). Animals were randomly divided into three groups. In the vehicle group, rats received an i.v. drip of physiological saline solution (PSS) at a rate of 0.3 mL/h. The LPS group received an i.v. drip of PSS for 1 h, followed by LPS (10 mg/kg by slow blous injection, i.v., over 1-2 min). Rats in the LPS + NAC group received NAC by i.v. drip at a rate of 150 mg/kg per h (0.3 mL/h) for 60 min starting 10 min before LPS administration (10 mg/kg by slow blous injection, i.v., over 1-2 min). Each group was observed for a period of 6 h. 4. N-Acetylcysteine treatment improved the LPS-induced hypotension and leukocytopenia. It also reduced the extent of ALI, as evidenced by reductions in LW changes, exhaled NO, PCBAL and lung pathology. In addition, NAC diminished the LPS-induced increases in nitrate/nitrite, MG, TNF-a and IL-1b. 5. In another series of experiments, LPS increased the mortality rate compared with the vehicle group (i.v. drip of PSS at a rate of 0.3 mL/h) during a 6 h observation period. N-Acetylcysteine, given 10 min prior to LPS, significantly increased the survival rate. 6. The results of the present study suggest that NAC exerts a protective effect on the LPS-induced ALI. The mechanisms of action may be mediated through the reduction of the production of NO, free radicals and pro-inflammatory cytokines.     

血浆中细菌内毒素定量测定方法的研究

目的:建立定量测定血浆中细菌内毒素的实验方法。方法:以内毒素检查用水制备标准曲线,动态浊度法定量测定分别采用3种抗凝剂的抗凝血中细菌内毒素的含量及回收率;以正常人血浆制备内毒素标准曲线,以抗增液复溶鲎试剂,动态浊度法定量测定人血浆中内毒素的含量及回收率。结果:使用肝素钠抗凝的血浆溶液对内毒素测定无干扰,而其他抗凝剂肝素锂、EDTA-K2等有干扰;人血浆经稀释加热处理,配合使用抗增液后制备的标准曲线与使用内毒素用水制备的标准曲线相比,可以更好地测定人血浆中细菌内毒素的含量,且具有较好的重现性;用所建立的方法测定肠癌患者血浆中内毒素的含量,其结果显著高于正常人血浆中内毒素的含量。结论:以肝素钠作抗凝剂,血浆经稀释加热处理并配合使用抗增液可定量测定血浆中细菌内毒素的含量。