细胞因子在猪呼吸道疾病中的作用

细胞因子如干扰素 α (IFN α) ,肿瘤坏死因子 α (TNF α) ,白细胞介素 1、 6和 8(IL 1、 6、 8) ,在多数感染的早期都会产生。它能调节细胞生长分化 ,调节免疫功能。这些细胞因子的活性已经在体外和小鼠试验中广泛研究 ,但有关细胞因子在肉用动物感染中的体内试验研究却很少。特别是病毒感染呼吸道后 ,细胞因子在体内出现的时间、机体临床表现以及抗病毒抗细菌感染的机理值得研究探讨。本文综述猪呼吸道感染中细胞因子的作用 ,并探讨其对呼吸道病毒性感染的相关性     

炎症因子在肉鸡呼吸道疾病中的变化及预警作用

为探讨炎症因子白细胞介素1(IL-1)、白细胞介素6(IL-6)、白细胞介素8(IL-8)、肿瘤坏死因子α(TNF-α)的变化是否可作为肉鸡呼吸道病的判定及预警指标,研究采用双抗体夹心ELISA法对120只随机挑选的不同日龄肉鸡血清中的4种炎症因子的含量进行动态监测,分析其含量变化与呼吸道病症之间的内在联系;同时对病原因素进行了检测。结果表明:在不同日龄的病死鸡中存在H9N2亚型禽流感病毒、新城疫病毒和传染性支气管炎病毒的感染,但未发现3种病毒共感染的现象;呼吸道感染初期IL-1、IL-6和TNF-α3种细胞因子含量显著增高,随着病情的加重,IL-8的含量逐渐升高。表明4种炎症因子的变化趋势与呼吸道病的发生发展有一定相关性,借助于4种因子的动态监测对于判断病情及预警具有重要的意义。     

α-干扰素在猪流感病毒感染急性期的作用

细胞因子，尤其是α-干扰素（IFN-α）在控制流感病毒感染过程中发挥着重要作用。为了研究IFN-α在流感过程中的作用，给感染流感病毒的模型动物猪接种IFN-α中和单克隆抗体（Abs）K9。首先确定了IFN-α中和Abs的最佳接种剂量与接种途径，据此研究Abs对猪流感病毒感染的效果。给猪气管内接种半数鸡胚感染量为10^6的H1N1流感病毒，接种18h后，分别给试验猪气管内和腹膜内注射高剂量的IFN—α中和Abs和对照Abs。     

神经肽S及其受体对伪狂犬病病毒感染的体外作用研究

为了解神经肽S(NPS)及其受体(NPSR)在伪狂犬病病毒(PRV)感染过程中的作用,本试验采用细胞培养、RT-PCR、实时荧光定量PCR及shRNA技术研究NPS和NPSR在PRV体外感染过程中的表达变化,以及NPS和NPSR对病毒基因和相关细胞因子的变化。RT-PCR和实时荧光定量PCR结果显示,PRV感染培养的小鼠胚胎成纤维细胞系(3T3细胞)后12和18 h,NPS和NPSR mRNA的表达水平极显著上升(P0.01);通过shRNA技术稳定干扰3T3细胞中NPSR表达后,PRV gE基因的表达极显著下调(P0.01);添加外源性NPS可显著增强PRV感染的3T3细胞PRV gE基因及细胞因子白介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)的表达水平(P0.05);添加NPSR抑制剂后,则极显著抑制细胞中PRV gE基因和细胞因子IL-6和TNF-α的表达水平(P0.01),该作用效果与NPS的作用效果相反。上述结果表明,降低NPSR的表达能有效抑制PRV在3T3细胞上的复制,说明NPSR是PRV有效感染3T3细胞所必需的重要因子;外源性NPS可通过调节炎症细胞因子的表达而加剧PRV感染诱导的炎症反应。本研究结果为深入探索NPS和NPSR在PRV感染动物体内的调节作用奠定了基础。     

基因A型鸭甲肝病毒弱毒株免疫雏鸭的8种细胞因子mRNA变化分析

为研究基因A型鸭甲肝病毒(DHAV-A)MY弱毒株对雏鸭细胞因子表达的影响,阐明细胞因子在DHAV-A弱毒疫苗免疫中的作用,利用荧光定量RT-PCR(RRT-PCR)方法,检测DHAV-A MY弱毒株接种1日龄SPF雏鸭后0.25、0.5、1、2、3和5d共6个时间点肝、脾和脑组织中IFN-α、IFN-β、IFN-γ,以及IL-1β、IL-2、IL-6、IL-8和TNF-α共8种细胞因子的mRNA转录水平,并结合各时间点DHAV-A的荷载量进行分析。结果表明:肝和脑组织中2d时间点以及脾组织中3d时间点病毒荷载量达到最高;三种组织中,8种细胞因子的转录水平均随着病毒荷载量的增加而升高,且在各组织病毒荷载量最高时间点,8种细胞因子的转录水平均极显著升高(P0.01),结果证明DHAV-A MY弱毒株可刺激雏鸭抗病毒细胞因子IFN-α、IFN-β、IFN-γ和TNF-α以及炎性细胞因子IL-1β、IL-2、IL-6和IL-8mRNA的转录,本研究丰富了DHAV-A MY弱毒株的免疫机制。     

神经介素B及其受体NMBR参与抗A型流感病毒H1N1亚型感染的信号通路

NMB/NMBR通过调节A型流感病毒（IAV/H1N1/PR8）感染诱导的细胞因子表达而参与抗IAV的先天性免疫反应。为探究其发挥抗IAV/H1N1感染的信号通路，本文用PR8和WSN毒株分别感染MLE-12细胞和小鼠，用NF-κB抑制剂BAY11-7028单独或联合NMB处理MLE-12细胞，小鼠后腿肌内注射NMB和NMBRA，采用RT-PCR和qRT-PCR分析NMB、NMBR、IL-6、IFN-α和NP基因表达变化，采用Western blot分析NMB、NMBR、P65/p-P65、IκBα和NP蛋白表达的变化。结果显示，BAY11-7028可促使PR8和WSN感染的MLE-12细胞中NMB、NMBR、IL-6和IFN-α基因表达水平均下降和NP基因表达水平上升，并降低NMB、NMBR和p-P65蛋白表达水平和提升IκBα和NP蛋白表达水平。然而，NMB联合BAY 11-7028诱导PR8或WSN感染后的细胞中IL-6和NP表达出现极显著下降和IFN-α显著上升。此外，NMB抑制PR8和WSN感染的小鼠肺组织内p-P65和NP蛋白表达水平和促进IκBα蛋白表达水平；NMBRA联合NMB抵消NMB对PR8或WSN感染后的这些蛋白表达水平的调节作用。综上表明，NMB/NMBR通过调节PR8和WSN感染的MLE-12细胞和小鼠体内的NF-κB信号通路上P65蛋白磷酸化和IκBα的表达，进而影响下游细胞因子IL-6和IFN-α基因的表达，从而发挥抗IAV/H1N1感染的先天性免疫应答反应。     

地塞米松对高致病性猪繁殖与呼吸综合征病毒感染仔猪的影响

为研究地塞米松(DEX)对高致病性猪繁殖与呼吸综合征病毒(HP-PRRSV)感染仔猪造成的免疫系统和呼吸系统损伤的影响,本实验在断奶仔猪感染HP-PRRSV Hu N4株前后,肌肉注射不同剂量的DEX,观察临床症状,检测其免疫系统相关指标的变化。结果显示:不同剂量DEX注射组实验猪均表现典型临床症状,虽然其外周血中的促炎性细胞因子IL-1β、IL-6及TNF-α水平降低,CD4+CD8-T淋巴细胞亚群比例较Hu N4单独感染组升高,CD8+CD4-T细胞比例较Hu N4单独感染组降低,但DEX注射组仔猪体温始终维持在40℃~42℃,肺部、胸腺和淋巴组织病变加重,死亡率达到100%(10/10),而Hu N4单独感染组仔猪死亡率仅为25%(1/4)。表明DEX对HP-PRRSV感染的断奶仔猪虽具有一定的抑制炎症反应作用,但加重了HP-PRRSV感染的不利影响。本研究为全面防控HP-PRRSV提供新的实验依据。     

细胞因子与分娩启动的关系

分娩启动是一个非常复杂的生理过程,受各种因素的制约和调节,一般认为是各种因素 共同作用的结果.近年来,关于分娩启动机制的研究很多,但迄今为止没有一个系统和权威 的结论.随着细胞因子研究的不断深入,人们发现细胞因子与分娩启动有着密切的关系,已 发现的细胞因子的种类很多,包括:白细胞介素(IL)、干扰素(IFN)、集落刺激因子(CSF) 、肿瘤坏死因子(TNF)等.目前,与分娩有关研究较多的细胞因子为:IL-1、IL-2、IL-6、I L-8和TNF-α.IL-1和IL-8在宫颈的成熟中起主要作用[1],IL-2可能促进前列 腺素合成以维持产程进展[2],IL-6与子宫组织合成前列腺素有关[3],有人认为TNF-α对于分娩启 动的作用并不大[2],但也有人认为TNF-α与分娩有关[4].本文就此五种细胞因子与分娩启动的关系作一综述.     

α-干扰素在猪流感病毒感染期间的作用

细胞因子,尤其是α-干扰素对控制流感病毒感染起重要作用。为了研究α-干扰素对控制流感的作用,用猪α-干扰素中和单克隆抗体K9来建立猪流感病毒感染模型。首先,确定α-干扰素中和单克隆抗体最佳剂量和给药途径,基于上述结果来研究单克隆抗体对猪流感病毒感染的作用。猪气管内接种106.0EID50A/Swine/Belgium/1/98(H1N1)病毒,接毒后18h,气管内和腹腔内注射高剂量α-干扰素中和单克隆抗体和对照抗体,分别于接种后0、24、30、48、72h对动物实施安乐死。在24、30h注射单克隆抗体K9的动物支气管肺泡灌洗液中α-干扰素水平被明显抑制,这与IL-6、IL-12水平降低一致。对照单克隆抗体处理组中α-干扰素和IL-1水平未受影响。重要的是α-干扰素中和单克隆抗体处理的动物临床症状出现和高峰要延迟24h,同时伴随α-干扰素的抑制,但对病毒复制和肺部病变无明显的作用。结果表明,在流感病毒症状中,α-干扰素对IL-6、IL-12诱导及3种细胞因子起重要作用。     

PYY对LPS诱导小鼠腹腔巨噬细胞TNF-α、IL-6分泌的影响

为明确PYY对巨噬细胞炎性细胞因子分泌的调节作用,本试验分离培养健康小鼠腹腔巨噬细胞,不同浓度PYY预处理后,以LPS刺激。ELISA方法检测细胞培养上清中TNF-α、IL-6含量,半定量PCR方法检测细胞中TNF-α、IL-6mRNA表达变化。结果显示:高浓度的PYY1-36(10-9¹0-7 mol/L)和PYY3-36(10-810-7 mol/L)和PYY3-36(10-8¹0-7 mol/L)对LPS诱导小鼠腹腔巨噬细胞TNF-α分泌具有显著抑制作用(P<0.05);PYY1-36对LPS诱导小鼠腹腔巨噬细胞IL-6分泌无明显作用(P>0.05);不同浓度PYY3-36(10-1110-7 mol/L)对LPS诱导小鼠腹腔巨噬细胞TNF-α分泌具有显著抑制作用(P<0.05);PYY1-36对LPS诱导小鼠腹腔巨噬细胞IL-6分泌无明显作用(P>0.05);不同浓度PYY3-36(10-11¹0-7 mol/L)对LPS诱导小鼠腹腔巨噬细胞IL-6分泌均具有显著抑制作用(P<0.05)。表明PYY对LPS诱导小鼠腹腔巨噬细胞炎性细胞因子TNF-α及IL-6的分泌具有一定的抑制作用,提示PYY可能通过抑制炎性细胞因子的分泌而抑制炎症性疾病的发生发展。     

Salmonella in pork cuttings in supermarkets and butchers' shops in Denmark in 2002 and 2006

The prevalence of Salmonella in fresh pork cuttings in Denmark in the years 2002 and 2006 was investigated at retail and compared with the retail supply pattern. A total of 1025 and 3473 samples were taken in 2002 from butcher's shops and supermarkets, respectively. The corresponding numbers in 2006 were 259 from butchers' shops and 628 from supermarkets. In 2002, 1.2% of all samples were positive for Salmonella; butchers' shops and supermarkets had 1.8% and 1.0% positive samples, respectively. The overall prevalence in 2006 was 4.2%, with prevalence of 8.1% and 2.6% for butchers' shops and supermarkets, respectively. Hence, increases around 3- to 5-fold were found. There was neither observed any parallel increase in Salmonella positive carcasses in Danish slaughterhouses during the study period, nor were any changes in supply routes towards slaughterhouses with higher prevalence observed, which could explain the apparent increase. We hypothesize that hygiene levels and ability to avoid cross-contamination and prevent growth of the organism, in the meat processing chain after slaughter were the most likely responsible factors. Results from this study indicate that the hygiene performance, particularly at retail, has a significant impact on the occurrence of Salmonella. This implies that there is no direct link between slaughterhouse Salmonella surveillance data and the level of Salmonella contamination at retail. To improve risk assessment of Salmonella in fresh pork meat, this study underlines the need for comprehensive retail data.     

Helminth and protozoan parasites in dogs and cats in Belgium

This study investigates the level of helminthic and protozoal infestation over the last 10 years in strays, well-cared-for dogs and cats. Determination of the prevalence of infections was based either on faecal examination or on worm counts at necropsy. Of 2324 faecal flotations (NaCl sp.gr. 1.20) of stray dogs, 34.2% had eggs or proglottids of one or more worm species consisting of Toxocara canis (17.4%), Toxascaris leonina (10.1%), Uncinaria stenocephala (11.4%), Trichuris vulpis (7.0%) and cestodes (2.1%). Isospora oocysts were observed in 5.2% of the dogs. The data on the distribution of the various worm species in the positive dogs indicate that T. canis eggs were by far the most common (50.9%). Necropsy data from 212 infected dogs indicate that 38.9% were infected with T. canis and 33.7% with T. leonina. The overall prevalence of worm infestation of 246 well-cared-for kennel dogs, based on worm egg counts by the McMaster technique, was 36.1%. Of 30 feline faecal samples examined by flotation, 83.3% were positive for parasites, including Toxocara cati (60%), Ancylostoma tubaeformae (36.6%), Taenia (Hydatigera) taeniaeformis (20%) and coccidia (30%). Toxocara cati was the most frequently found worm species at the necropsy of 25 cats (52%). Toxoplasma was not observed.     

Sanguinarine metabolism and pharmacokinetics study in vitro and in vivo

Sanguinarine (SA) is a benzo[c] phenanthridine alkaloid which has a variety of pharmacological properties. However, very little was known about the pharmacokinetics of SA and its metabolite dihydrosanguinarine (DHSA) in pigs. The purpose of this work was to study the intestinal metabolism of SA in vitro and in vivo. Reductive metabolite DHSA was detected during incubation of SA with intestinal mucosa microsomes, cytosol, and gut flora. After oral (p.o.) administration of SA, the result showed SA might be reduced to DHSA in pig intestine. After i.m. administration, SA and DHSA rapidly increased to reach their peak concentrations (C_max, 30.16 ± 5.85, 5.61 ± 0.73 ng/ml, respectively) at 0.25 hr. Both compounds were completely eliminated from the plasma after 24 hr. After single oral administration, SA and DHSA rapidly increased to reach their C_max (3.41 ± 0.36, 2.41 ± 0.24 ng/ml, respectively) at 2.75 ± 0.27 hr. The half-life (T_1/2) values were 2.33 ± 0.11 hr and 2.20 ± 0.12 hr for SA and DHSA, respectively. After multiple oral administration, the average steady-state concentrations (C_ss) of SA and DHSA were 3.03 ± 0.39 and 1.42 ± 0.20 ng/ml. The accumulation indexes for SA and DHSA were 1.21 and 1.11. The work reported here provides important information on the metabolism sites and pharmacokinetic character of SA. It explains the reasons for low toxicity of SA, which is useful for the evaluation of its performance.     

Chlortetracycline in swine-bioavailability and pharmacokinetics in fasted and fed pigs

Chlortetracycline hydrochloride was administered intra-arterially (11 mg/kg) and as an oral drench (33 mg/kg) to ten 21.0-31.5-kg pigs. Five of the pigs were fasted 18 h prior to dosing and five of the pigs were fed ad libitum prior to dosing. The mean volume of distribution determined by area-under-the-curve calculations for the fasted pigs (0.967 +/- 0.210 l/kg) was significantly less (P less than 0.05) than the mean volume of distribution for the fed pigs (1.39 +/- 0.31 l/kg). Mean total body clearance of the drug was also significantly less (P less than 0.05) in the fasted pigs (0.165 +/- 0.055 l/kg/h) as compared to the fed pigs (0.307 +/- 0.053 l/kg/h). The elimination constants (beta) were not found to be statistically different (P less than 0.05): 0.1811 +/- 0.0057 for the fasted pigs; 0.2260 +/- 0.0461 for the fed pigs. The bioavailability for both groups was similar; 19.12 +/- 8.3% for the fasted pigs and 17.88 +/- 5.3% for the fed pigs. In a second experiment three groups of six pigs which weighed 34.5-44.1 kg were fed a corn-soy diet ad libitum. The rations were fortified with chlortetracycline at 100, 400 or 1000 mg chlortetracycline hydrochloride/kg feed. Chlortetracycline concentrations were determined in plasma samples collected over a 6-day period. Plasma chlortetracycline concentrations reach a plateau within 24 h after initial access to the trial diets and were highly correlated with the dose of the drug consumed (r2 = 0.97).     

2005年国内蛋、肉鸡市场分析回顾及2006年走势预测

2005年如果没有年底的禽流感疫情,对于我国蛋鸡、肉鸡生产来说应该是一个非常完美的丰收年,是哪些因素导致了2005年蛋鸡市场如此好的行情?2006年我国家禽市场又将走向何方?……作者对以上热点问题进行了深入分析研究,供读者参考。     

Pharmacokinetics of penicillin-G in ewes and cows in late pregnancy and in early lactation

Concentrations of penicillin-G in serum were determined after single intravenous doses of potassium penicillin-G (10 mg/kg body wt) to ewes and cows in late pregnancy and in early lactation. Penicillin-G in serum was analysed by a microbiological method and pharmacokinetic parameters were calculated by model-independent methods. Serum concentrations were lower in early lactation than in late pregnancy in both ewes and cows. The differences were statistically significant at most sampling times in ewes but only during the first hour in cows.
Weight corrected values of clearance and volume of distribution were significantly higher in early lactation than in late pregnancy in both ewes and cows. Mean residence time and elimination-half life were shorter in lactating than in pregnant ewes, however for the latter parameter the difference was not statistically significant. Neither of these parameters changed in cows.
It is concluded that in both ewes and cows pharmacokinetic parameters of penicillin-G are altered from late pregnancy to early lactation but that these changes have little practical impact and do not call for a revised dosage regime of the studied drug.     

Mycobiota and aflatoxins in raw materials and pet food in Brazil

Commercial feedstuffs are a basic element in modern pet husbandry in the world. In dogs, the effect of mycotoxins is severe and can lead to death. Few reports on the influence of dietary mycotoxins were found in the scientific literature. The aims of this work were to isolate and identify the mycoflora and to determine the aflatoxins (AFs) natural occurrence in raw materials and ready dry pet food. Therefore, the aflatoxigenic capacity of Aspergillus flavus species was investigated. Aspergillus was the prevalent genera (65-89%) followed by Penicillium and Fusarium spp. Aspergillus flavus was the most prevalent species, followed by Aspergillus sydowii, Aspergillus fumigatus and Aspergillus versicolor. Aspergillus flavus frequencies ranged from 58% to 86% except in sorghum meal. All samples assayed (except corn grains and ready pet food) showed Fusarium spp. contamination. Corn meal and corn meal and gluten samples had 100% Fusarium verticillioides. Fusarium graminearum was isolated from sorghum meal. Aspergillus flavus strains (75%) isolated from raw materials and 57% from pet food were able to produce AFs. All samples showed AFs contamination percentages over 70%; corn and sorghum meal obtained the highest AFs levels. Ready pet food did not show quantitative levels of the tested toxins. This is the first report of the aflatoxigenic capacity by A. flavus from Brazilian pet food.