Pathology of 2-alkyl and 2-hydroxy naphthoquinone toxicity in rats

Extract

The oral administration of 2-methyl-1, 4-naphthoquinone (menadione) to rats caused oxidative destruction of the erythrocyte. Heinz body formation occurred in erythrocytes, lowered PCVs and haemoglobin Occurred in blood, with splenic and hepatic erythroclasis, and iron conservation in the spleen, liver and kidney. These effects diminished when increasingly large alkyl substitutions of the methyl group of thi naphthoquinone were made. No effect was caused by the 2-decyl derivative.     

Serum glucocorticoids, growth hormone and insulin and plasma glucose in bulls given prostaglandin E2 or F2 alpha 1.

Plasma glucose and serum insulin, growth hormone and glucocorticoid concentrations were determined in five yearling bulls given (im) 5, 15 or 30 mg prostaglandin E2 (PGE2), 30 mg prostaglandin F2 alpha(PGF2 alpha) or saline. Jugular blood was collected at frequent intervals around the time of injection and at .5--hr intervals from 1 to 9 hr after injections. Thirty milligrams PGE2 and 30 mg PGF2 alpha each caused 15- to 20-fold increases in serum glucocorticoids. Glucocorticoids increased with increasing doses of PGE2. Although PGE2 and PGF2 alpha each increased blood growth hormone, this effect was about twofold larger after PGE2. By contrast, PGE2 depressed serum insulin about 50% for 1 hr, then insulin increased about sixfold until 3 to 4 hours. Blood serum insulin increased after PGF2 alpha, but this effect only approached significance (P less than .10). Plasma glucose increased about 10 mg/100 ml after PGE2, but was not affected significantly by PGF2 alpha. Thus, the effects of PGE2 and PGF2 alpha on hormones which control glucose metabolism differ markedly. We speculate that PGE2 caused a twofold increase in growth hormone secretion within 10 to 20 min, that increased growth hormone induced increased blood glucose within 1 to 2 hr and that increased glucose caused increased insulin secretion at 2 to 4 hr, but we cannot rule out a transitory (1 hr) suppressive effect of PGE2 directly on the pancreas.     

First isolation of EBLV-2 in Germany

In Europe, rabies in bats is caused by European Bat Lyssavirus (EBLV) type 1 (EBLV-1) or type 2 (EBLV-2) which form two distinct genotypes (gt 5 and 6) within the genus Lyssavirus of the family of Rhadoviridae. Spill-over infections of EBLV in humans have caused fatal rabies encephalitis and highlighted the relevance of this wildlife disease for public health. The vast majority of the 831 European bat rabies cases reported between 1977 and 2006 were identified as EBLV-1. Only few virus isolates originating from Switzerland, The Netherlands and the United Kingdom were characterized as EBLV-2. Here we report the first EBLV-2 case detected in Germany in a Daubenton's bat (Myotis daubentonii) in August 2007. The bat showed clinical signs of disorders of the central nervous system and subsequently tested positive for rabies. The virus was isolated and characterized as EBLV-2 based on its antigen pattern and by nucleotide sequencing. Phylogenetic analysis indicated an association to EBLV-2 isolates from Switzerland which correlates with the origin of the bat close to the Swiss border.     

猪圆环病毒2型疫苗研究进展

猪圆环病毒2型主要引起断奶仔猪多系统衰竭综合征,在包括中国在内的各养猪国家广泛流行,造成严重的经济损失,受到国内外学者的高度重视,对此病的研究特别是对其疫苗的研究正日益受到关注.文章就猪圆环病毒2型的灭活疫苗、弱毒疫苗和基因工程疫苗的研究进展做了详细的阐述.     

Alpha-2 adrenoreceptors mediate clonidine-induced hypoinsulinaemia in sheep

Insulin and glucose concentrations in the blood of sheep were measured before, and up to 7 h after, feeding. The patterns reported by other workers were confirmed, namely: an early insulin concentration peak and decline in glucose concentration and, later, more prolonged changes. Intravenous injection of clonidine (2 micrograms/kg or 5 micrograms/kg) just before offering food caused hypoinsulinaemia and hyperglycaemia, abolishing the normal patterns. Administration of idazoxan (0.1 mg kg-1), an alpha-2 adrenoreceptor antagonist, before a 2 micrograms/kg dose of clonidine, completely blocked the effects of clonidine. By contrast, with prior injection of prazosin (0.1 mg/kg), an alpha-1 adrenoreceptor antagonist, the hypoinsulinaemia in response to clonidine still occurred and the hyperglycaemia appeared to be enhanced. The antagonists injected alone had only slight effects: idazoxan caused a slight hypoglycaemia and prazosin a slight hyperglycaemia. The results indicate that clonidine causes hypoinsulinaemia and hyperglycaemia by action on alpha-2 receptors. Possible mechanisms are discussed.     

猪圆环病毒2型基因组DNA的结构与功能研究进展

猪圆环病毒2型(PCV2)是引起猪圆环病毒病相关疾病的主要致病原,可损伤宿主的免疫系统,加剧一些细菌病和病毒病感染的临床症状,在全球养猪业中造成巨大损失。PCV2的基因组DNA含有11个开放阅读框(ORFs),其中至少有7个ORFs编码的蛋白质分子质量大于5ku,但目前只有5种编码的蛋白(Rep、Rep'、Cap、ORF3和ORF4)发现于PCV2复制过程中。作者概述了当前PCV2基因组DNA的结构与功能,阐明PCV2的病原学,为防控PCV2感染提供科学依据。     

Advances on Structure and Function of Genomic DNA of Porcine Circovirus Type 2

Porcine circovirus type 2 (PCV2) is a disease caused by porcine circovirus, which can damage the host's immune system and exacerbate the clinical symptoms of many bacterial and viral infections.It has caused increasingly larger losses in the pig industry wordwide.The genomic DNA of PCV2 contains 11 open reading frames (ORFs) and at least seven potential ORFs-encoding proteins larger than 5 ku.However, only five virally encoded proteins, including Rep, Rep', Cap, ORF3 and ORF4, had been identified in PCV2 replication.In this review, we discussed the progress on structure and function of genomic DNA of PCV2 in order to provide insight into the scientific basis of the pathogenesis of PCV2 and prevent its infection.     

胰高血糖素样肽-2及其在畜牧生产中的应用

胰高血糖素样肽-2（GLP-2）是一条由33个氨基酸残基组成的短肽,主要由位于小肠的边缘和结肠中的L内分泌细胞分泌,与其受体（GLP-2R）结合激活一系列下游的反应来实现其功能。GLP-2具有促进肠道生长发育,修复受损伤肠道,加快营养物质转运与吸收,增强肠黏膜屏障功能等生理作用,目前GLP-2及GLP-2类似物（[Gly-2]GLP-2）已被批准用于治疗短肠综合征等人类肠黏膜损伤性疾病。此外,由于GLP-2功能具有多样性,在畜牧生产上也有广阔的应用前景。如GLP-2可以用于家畜常见的一些肠胃炎的治疗,可用来缓解牛败血症引起的肺脏损伤,在维持肝脏健康方面也可发挥重要作用,还可作为一种厌食信号肽来增加食物在家畜中的转化率,以及用于缓解周围环境改变而引起的家畜不良应激反应,如热应激、缺水应激、氟中毒、饮食转换期间肠功能受损等问题。作者就GLP-2的最新研究进展及其在畜牧生产中的应用进行阐述。     

中国首例兔出血症病毒2型(RHDV2/b/GI.2)的鉴定及病理学观察

本试验旨在鉴定四川金堂某兔场疑似兔出血症病毒2型（RHDV2）感染疫情的病原,并分析病兔的病理组织学变化。利用血凝试验和RT-PCR检测病死兔内脏组织中的病原,取病变组织制作病理切片,观察分析各组织的病理组织学变化,同时应用病兔肝脏悬液感染幼兔,分析该毒株的致病力。血凝试验结果显示,所采集病死兔肝脏样品能凝集人"O"型血红细胞;RT-PCR扩增及测序结果显示,多对引物均能从样品中扩增出RHDV2特异性条带;病理组织学观察结果显示,病兔多脏器严重出血、肿胀,淋巴细胞和中性粒细胞大量浸润,气管黏膜、肝脏、肺脏出血尤为严重;动物试验结果显示,该毒株毒力较强,含毒肝脏悬液能在24 h内迅速致死幼兔。本研究经临床诊断、核酸检测及测序证实了此次疫情确由RHDV2感染引起,动物试验和病理组织学观察表明该毒株毒力较强,可引发脏器严重出血,造成病兔急性死亡,RHDV2的出现提示病毒的跨境传播情况不容乐观,应引起更大的重视。     

猪圆环病毒2型检测技术研究进展

猪圆环病毒2型感染常引起不同生长阶段猪的免疫系统损伤,造成猪机体免疫功能不全和对疾病高度易感,给养猪业带来巨大损失,所以建立一种快速的检测技术对该病的防制至关重要,目前国内外许多学者对检测方法做了大量研究,文章对PCV2的检测方法作一介绍。     

The prevalence of ovine herpesvirus-2 in 4 sheep breeds from different regions in South Africa

About 90% of bovine malignant catarrhal fever (BMCF) PCR-positive cases in South Africa are caused by alcelaphine herpesvirus-1 (AlHV-1) and the other 10% by ovine herpesvirus-2 (OvHV-2). The prevalence of OvHV-2 in different sheep breeds in South Africa was determined in order to investigate whether the lower incidence of BMCF caused by OvHV-2 in comparison with AlHV-1 can be ascribed to a low incidence of the virus in sheep. A single-tube hemi-nested PCR was developed, evaluated and applied to detect OvHV-2 DNA. The prevalence of the virus in 4 sheep breeds from various regions in South Africa was shown to be 77%. No statistically significant difference was found amongst the sheep breeds tested.     

猪圆环病毒2型致病机制研究进展

猪圆环病毒2型(PCV-2)感染可导致一系列病征,包括断奶仔猪多系统衰竭征(PMWS)、仔猪先天性震颤(CT)、母猪繁殖障碍、猪皮炎肾病综合征(PDNS)及猪呼吸道综合征(PRDC),其中以PMWS对养猪业危害最大.PCV-2具有自身特有生物学特性.PCV-2可感染不同年龄段猪而产生临床上症状不同的疾病,能诱发仔猪产生免疫抑制后继发感染和混合感染其他病原.论文结合PCV-2的分子生物学特性和发病特征,从分子生物学角度、病毒组织嗜性、宿主细胞增殖特性及免疫刺激方面,对PCV-2致病机制进行综述,为防控PCV-2感染提供参考.     

Porcine circovirus type 2 (PCV2) and Campylobacter infection induce diarrhea in piglets: Microbial dysbiosis and intestinal disorder

Diarrhea is considered to be associated with microbial dysbiosis caused by infection of pathogens but poorly understood. We herein characterized the colonic microbiota of diarrheal early-weaning piglets infected with porcine circovirus type 2 (PCV2) and Campylobacter. Campylobacter infection significantly decreased species richness and Shannon diversity index of colonic microbiota together with a significant increase in the proportion of Campylobacter and Enterobacteriaceae, whereas no significant difference on the above indexes was observed in piglets infected with PCV2 compared with healthy piglets. PCV2 and Campylobacter infection could disturb the homeostasis of colonic microbiota through deterioration of ecological network within microbial community, and specially Campylobacter performed as a module hub in ecological networks. The microbial dysbiosis caused metabolic dysfunction and led to a remarkable reduction in production of short chain fatty acids, following by a higher pH level in colon cavity. Campylobacter infection disturbed the function of colonic tract barrier observed in terms of significant lower relative expression of claudin-1, occluding, and zonula occludens protein-1 genes, and PCV2 infection induced intestinal inflammation together with a higher permeability of colon. Generally, these results suggested that PCV2 and Campylobacter infection could induce microbial dysbiosis and metabolic dysfunction, and cause intestinal disorder, all of which finally were associated to contribute to the diarrhea of early-weaning piglets.     

Subacute toxicity of Dietary T-2 toxin in mice: influence of protein nutrition.

The subacute toxic effects of dietary T-2 toxin (20 ppm) incorporated in semipurified diets of 8%, 12% or 16% protein, were examined in young Swiss mice after one, two, three and four weeks. Dietary T-2 toxin caused substantial reductions in growth and food consumptaion, the degrees of which were greatest in mice fed the diets of reduced protein content. T-2 toxin consistently caused similar degrees of nonregenerative anemia, lymphopenia, thymic atrophy and gastric hyperkeratosis irrespective of the dietary protein level. However, erythroid hypoplasia was temporary in mice fed T-2 toxin in the 16%-protein diet such that erythroid precursors regenerated in splenic and bone marrow and were hyperplastic after four weeks. Liver to body weight ratios of mice fed T-2 toxin in the 16%-and 12%-protein diets increased during the four week trial in comparison to control mice fed at a similar rate. These observations indicated that suppression of erythropoiesis in mice by dietary T-2 toxin was temporarty and that the interval before regeneration was prolonged by diets of reduced protein content.     

规模化猪场猪圆环病毒2型感染的流行病学调查

20 0 1年 11月至 2 0 0 2年 8月 ,对北京、天津、广东、深圳、山东、山西等地 12个规模化猪场猪圆环病毒 2型 (PCV2 )感染发病群猪进行了临床发病情况调查 ,并采用 PCR方法对所收集的 5 5份组织病料进行 PCV2的检测 ,结果表明 ,12个猪场中有 11个猪场发病猪群表现为断奶后多系统衰竭综合征 ,1个猪场表现为皮炎和肾病综合征。由此可见 ,PCV2感染在我国规模化猪场已普遍存在     

猪圆环病毒2型疫苗研究进展

猪圆环病毒2型(PCV2)感染后会导致断奶仔猪多系统衰竭综合征(PMWS)等"猪圆环病毒相关疾病"(PCVADs),给全球养猪业造成了巨大的经济损失。疫苗免疫是防控该病的有效手段,近年来市场上推出了PCV2灭活疫苗、嵌合疫苗和亚单位疫苗。PCV2变异较快,主要临床流行毒株从PCV2b逐渐演变为PCV2d,现有商业化疫苗免疫效果需进一步研究证实。论文就近年来国内外PCV2传统疫苗、新型基因工程疫苗、PCV2疫苗与其他疫苗联合免疫的研究进展进行综述,旨在为猪圆环病毒相关疾病的防控及疫苗的开发与利用提供参考。     

PCV2感染对仔猪NO-NOS系统的动态影响

将19头PCV2和PRRSV血清抗体阴性的普通断奶仔猪分为对照组(4头)和攻毒组(15头),攻毒组每头仔猪滴鼻接种PCV2病毒悬液4mL(5×105 TCID50/mL)并用KLH刺激,分别在攻毒后14、21、35d各扑杀5头仔猪采集血清和脾脏、淋巴结、胸腺(对照组4头在攻毒当天扑杀)。检测各种组织中NO、TNOS和iNOS的含量。结果显示,攻毒猪各组织中NO含量均在攻毒后14d显著升高(P<0.05),然后缓慢下降;血清和3种免疫器官中NOS(包括TNOS和iNOS)活性的变化趋势比较一致,均表现出先升高然后再逐渐降低的特点。此外,iNOS活性变化与其相应的组织中NO含量呈显著正相关(P<0.01)。结果表明,PCV2在感染早期(1～14d)可激活仔猪多种组织中NO-NOS系统,中后期逐渐恢复,这种变化与PCV2所致的组织损伤密切相关,因此,NO-NOS系统可能是PCV2相关疾病发生发展的重要信号。     

Effect of cortisol in vitro and in vivo on production of bovine interleukin 2

The influence of cortisol in vitro and in vivo on lymphocyte proliferative responses and interleukin 2 (IL2) production was evaluated in Hereford feeder calves. Cortisol, added to bovine mononuclear cell cultures, reduced (P less than 0.05) mitogen-stimulated lymphocyte proliferative responses and IL2 production. Lower IL2 activity from cortisol-treated cell cultures was not caused by a cortisol-mediated cytotoxicity or a residual cortisol effect on the IL2-indicator cell line. Calves given ACTH (1.0 IU/kg of body weight, IM) twice daily for 2 days had increased (P less than 0.001) plasma cortisol concentrations when compared with those of saline-treated controls. Leukocytosis (P less than 0.002), characterized mainly by a neutrophilia (P less than 0.007), was evident in ACTH-treated calves. Lymphocyte proliferative responses to the phytomitogens, concanavalin A, phytohemagglutinin, and pokeweed mitogen were decreased (P less than 0.05) in calves with increased plasma cortisol concentrations. Interleukin 2 production was lower (P less than 0.05) in concanavalin A-stimulated lymphocyte cultures from ACTH-treated calves. Seemingly, lower lymphocyte proliferative responses in cortisol-treated mononuclear cell cultures and in ACTH-treated calves were caused partly by lower IL2 production.