Diving-for-Food: A New Model to Assess Social Roles in a Group of Laboratory Rats

In an experimental situation called “diving for food”, groups of laboratory rats are tested in an aquarium where they have to dive and swim under water to reach the single source of food located at the other end. A behavioural differentiation appears: some rats — the carriers — dive to get food and others — non-carriers — stay in the cage and feed by stealing. We examine whether carrier and non-carrier profiles can be considered as social roles, defined as supraindividual features dependent on the social context. Carrier/non-carrier differentiation resulted in all groups tested. Individually tested, almost all rats can get food by diving and swimming. Differentiation also occurred in groups that had been previously trained alone in the device, and in groups whose members had all been carriers or non-carriers exclusively in a preliminary stage. As the access-to-food behaviour of a rat having to cope with the diving-for-food situation is settled by its social environment, we consider that the present experimental model is promising for the study of interactions between the individual and the social structure.     

卡氏肺孢子虫感染小鼠动物模型的研究

采用肾上腺皮质激素的方法在国产昆明小鼠成功诱导卜氏肺孢子虫感染,在54只实验鼠中,47只发现虫体,阳性率为87．03％,表明该方法可透用于建立卡氏肺孢子虫感染的小鼠动物模型,并具有简便,经济等优点。     

HFJ大鼠与Wistar大鼠用于动脉粥样硬化造模的比较研究

目的通过高脂喂养和免疫损伤结合的方法,建立HFJ近交系大鼠和Wistar封闭群大鼠动脉粥样硬化动物模型并进行比较分析。方法选择HFJ近交系和Wistar封闭群大鼠,分别随机分为模型组和正常组,正常组给予基础饲料饲喂,模型组给予高脂饲料饲喂,并采用牛血清白蛋白(40mg/kg)和卵清白蛋白(2.5mg/kg)进行免疫损伤,并辅以维生素D3(25万U/kg)灌胃,饲养90d后测定血脂水平、血液生化指标、观察病理变化和血管内皮生长因子(VEGF)免疫组化情况。结果 (1)HFJ和Wistar大鼠正常组相比较,前者TG、TC和LDL-C水平高于后者(P<0.05),HFJ大鼠模型组LDL-C含量明显高于Wistar大鼠(P<0.05);(2)心肌损伤指标,HFJ和Wistar大鼠模型组均较正常组心肌激酶(CK)、心肌激酶同工酶(CK-Mb)明显升高;(3)HE染色发现与Wistar大鼠模型组相比,HFJ近交系大鼠斑块形成更为明显,明显处于动脉粥样硬化病理Ⅲ期,可见纤维帽形成,纤维帽下具有典型的胆固醇结晶裂隙和泡沫细胞,中层平滑肌排列紊乱;(4)免疫组化法测定主动脉弓VEGF蛋白的表达,HFJ大鼠模型组较Wistar大鼠表达升高(P<0.05)。结论成功建立了HFJ大鼠动脉粥样硬化疾病动物模型,与Wistar大鼠相比HFJ大鼠模型特点更为显著,可为动脉粥样硬化研究提供一新的实验动物品系。     

同种异基因骨髓移植GVHD动物模型的建立及其病理生理学机制初探

目的：建立稳定的异基因骨髓移植GVHD（移植物抗宿主病）动物模型,并初步了解其病理生理学机制。方法：以BALB／c（H-2^d）雌性小鼠为受者,接受8Gy致死剂量的。Co全身照射后,输注雄性C57BL／6（H-2^b）供鼠的脾细胞和骨髓细胞,观察受鼠的体征、造血功能恢复及生存时间的变化,并进行病理学、嵌合体和T细胞亚群及相关细胞因子的检查。结果：模型组小鼠在移植后出现了典型的GVHD症状;肠、肝、脾、皮肤的病理学分析均属于Ⅳ度GVHD;嵌合体植入成功;以7、14和21d为检测时间点,发现模型组鼠体内T细胞亚群移植后较移植前CD3^＋CD4^＋T细胞数量减少,CD3＋CD8＋T细胞显著升高,CD4^＋和CD8^＋T细胞比例严重倒置,随着时间变化比值会逐渐升高,但仍然处于较显著的倒置水平;血清中IFN-γ、TNF-α在移植后＋7d表达显著增高,尤其是IFN-γ的表达在＋7d达峰值;IL-4和IL-10的水平在移植前后几乎没有变化。结论：建立了稳定的GVHD动物模型;此模型发病过程中,CD8^＋T细胞介导的CTL细胞毒性作用可能要大于CD4＋Th介导的细胞因子效应;IFN-γ、TNF-α炎症因子在GVHD的早期发挥重要作用;IL-4、IL-10的低水平分泌与急性GVHD的高发病率有关。     

A Marked Increase in Free Copper Levels in the Plasma and Liver of LEC Rats: An Animal Model for Wilson Disease and Liver Cancer

Most of copper present in rat plasma and liver binds to caeruloplasmin and metallothionein, respectively, and is not redox active. However, free forms of copper including loosely bound forms to other molecules are redox active. We assessed the free copper in Long-Evans rats with a cinnamon-like coat color (LEC rats), an animal model of Wilson disease and liver cancer. Compared to those of control rats, the liver and plasma of LEC rats showed a marked elevation of free copper, especially at the stage of acute hepatitis, in parallel with an increase of total copper levels in the livers and a decrease of plasma caeruloplasmin (ferroxidase I) activity. At the onset of jaundice, the total copper levels, however, decreased in liver, but increased in plasma, while free copper levels in both liver and plasma remained higher. Free iron levels in both liver and plasma were also determined and did not change significantly, except for the case of plasma in jaundiced rats. The data are consistent with a proposal in which increased levels of redox active free copper in the liver of LEC rats catalyze Fenton-type reactions, producing a large flux of hydroxyl radicals that would play an important role in the observed liver dysfunction, leading to acute hepatitis, and, finally, hepatocarcinoma. This is the first demonstration that the free copper may participate in the pathophysiology of the LEC rats and Wilson disease.     

Development of a Heterologous Model in Germfree Suckling Rats for Studies of Rotavirus Diarrhea

Germfree suckling rats were infected with an SA11 rotavirus strain. Infected pups developed diarrhea associated with histopathological changes. The virus was detected in feces and in the small intestine. Cellular vacuolation was observed in the villi of the jejunum. These results provide a new model for further investigations of group A rotavirus infection.     

Expression and Immunoreactivity of a Human Group A Rotavirus Vp4

Rotavirus capsid protein Vp4 plays an important role in the virus adhering and entering the cells. In this study, a Vp4 gene cloned from a rotavirus strain TB-Chen was highly expressed in E.coli BL21 (DE3). The results of the Western blot showed that the protein possesses specific immuno-reactivities and can be specifically recognized by guinea pig antibodies against rotavirus strain SA11 or Wa. Some Vp4 dimers were formed during renaturation. These data obtained from this study provide a strong basis for further study on the structure and function of the Vp4.     

Gastrointestinal Infections and Diarrheal Disease in Ghanaian Infants and Children: An Outpatient Case-Control Study

IntroductionDiarrheal diseases are among the most frequent causes of morbidity and mortality in children worldwide, especially in resource-poor areas. This case-control study assessed the associations between gastrointestinal infections and diarrhea in children from rural Ghana.MethodsStool samples were collected from 548 children with diarrhea and from 686 without gastrointestinal symptoms visiting a hospital from 2007–2008. Samples were analyzed by microscopy and molecular methods.ResultsThe organisms most frequently detected in symptomatic cases were Giardia lamblia, Shigella spp./ enteroinvasive Escherichia coli (EIEC), and Campylobacter jejuni. Infections with rotavirus (adjusted odds ratio [aOR] = 8.4; 95% confidence interval [CI]: 4.3–16.6), C. parvum/hominis (aOR = 2.7; 95% CI: 1.4–5.2) and norovirus (aOR = 2.0; 95%CI: 1.3–3.0) showed the strongest association with diarrhea. The highest attributable fractions (AF) for diarrhea were estimated for rotavirus (AF = 14.3%; 95% CI: 10.9–17.5%), Shigella spp./EIEC (AF = 10.5%; 95% CI: 3.5–17.1%), and norovirus (AF = 8.2%; 95% CI 3.2–12.9%). Co-infections occurred frequently and most infections presented themselves independently of other infections. However, infections with E. dispar, C. jejuni, and norovirus were observed more often in the presence of G. lamblia.ConclusionsDiarrheal diseases in children from a rural area in sub-Saharan Africa are mainly due to infections with rotavirus, Shigella spp./EIEC, and norovirus. These associations are strongly age-dependent, which should be considered when diagnosing causes of diarrhea. The presented results are informative for both clinicians treating gastrointestinal infections as well as public health experts designing control programs against diarrheal diseases.     

A组人轮状病毒全基因组克隆和基因型分析

运用基因克隆和重组技术,从一急性胃肠炎患儿样品中克隆到一株轮状病毒（RV）全基因组cDNA。核苷酸序列测定结果表明,该株RV基因组11条RNA共含有18613个核苷酸（3302bp—751bp）,编码5791个氨基酸。全基因组研究结果表明,该株RV（TB-Chen）为A组,II亚组,基因型为G2P[4]/NSP4[A]。这是首个A组人RV全基因组研究结果的报道,对研究和开发RV疫苗具有积极的意义。     

A Neutralizing Human Monoclonal Antibody Protects against Lethal Disease in a New Ferret Model of Acute Nipah Virus Infection

Nipah virus is a broadly tropic and highly pathogenic zoonotic paramyxovirus in the genus Henipavirus whose natural reservoirs are several species of Pteropus fruit bats. Nipah virus has repeatedly caused outbreaks over the past decade associated with a severe and often fatal disease in humans and animals. Here, a new ferret model of Nipah virus pathogenesis is described where both respiratory and neurological disease are present in infected animals. Severe disease occurs with viral doses as low as 500 TCID₅₀ within 6 to 10 days following infection. The underlying pathology seen in the ferret closely resembles that seen in Nipah virus infected humans, characterized as a widespread multisystemic vasculitis, with virus replicating in highly vascular tissues including lung, spleen and brain, with recoverable virus from a variety of tissues. Using this ferret model a cross-reactive neutralizing human monoclonal antibody, m102.4, targeting the henipavirus G glycoprotein was evaluated in vivo as a potential therapeutic agent. All ferrets that received m102.4 ten hours following a high dose oral-nasal Nipah virus challenge were protected from disease while all controls died. This study is the first successful post-exposure passive antibody therapy for Nipah virus using a human monoclonal antibody.     

Group A Rotavirus as a Cause of Neonatal Calf Enteritis in Sweden

Faeces samples were collected during outbreaks of neonatal calf diarrhoea in 14 beef and dairy herds. Samples from 33 calves were taken at the onset of diarrhoea as well as from 30 calves with no signs of enteritis. No vaccines or medical treatment had previously been given. The mean age of the calves was 16.8 days (SD 8.2). The clinical evaluation of faeces consistency corresponded well to the dry matter content of the faeces (p<0.001). The samples were analyzed for rotavirus, Cryptosporidium species and Escherichia coli K99+. Group A rotavirus was detected by ELISA and RNA Polyacrylamide gel electrophoresis (RNA-PAGE) in 14/33 (43.8%) of the samples from scouring calves and 1/30 (3.7%) of the samples from non-scouring calves. The correlation between group A rotavirus and diarrhoea was statistically significant (p<0.001). No non-group A rotaviruses were found by RNA-PAGE. Cryptosporidium species were detected through demonstration of oocysts in smears from 12/63 (19.0%) of the faecal samples, but no statistically significant correlation between diarrhoea and detection of oocysts was demonstrated. Escherichia coli K99+ was not detected in any faeces sample. The clear association between group A rotavirus and diarrhoea is suggested to be due to low pathogenic load in the herds.     

Impact of Thoracic Surgery on Cardiac Morphology and Function in Small Animal Models of Heart Disease: A Cardiac MRI Study in Rats

Background

Surgical procedures in small animal models of heart disease might evoke alterations in cardiac morphology and function. The aim of this study was to reveal and quantify such potential artificial early or long term effects in vivo, which might account for a significant bias in basic cardiovascular research, and, therefore, could potentially question the meaning of respective studies.

Methods

Female Wistar rats (n = 6 per group) were matched for weight and assorted for sham left coronary artery ligation or control. Cardiac morphology and function was then investigated in vivo by cine magnetic resonance imaging at 7 Tesla 1 and 8 weeks after the surgical procedure. The time course of metabolic and inflammatory blood parameters was determined in addition.

Results

Compared to healthy controls, rats after sham surgery showed a lower body weight both 1 week (267.5±10.6 vs. 317.0±11.3 g, n<0.05) and 8 weeks (317.0±21.1 vs. 358.7±22.4 g, n<0.05) after the intervention. Left and right ventricular morphology and function were not different in absolute measures in both groups 1 week after surgery. However, there was a confined difference in several cardiac parameters normalized to the body weight (bw), such as myocardial mass (2.19±0.30/0.83±0.13 vs. 1.85±0.22/0.70±0.07 mg left/right per g bw, p<0.05), or enddiastolic ventricular volume (1.31±0.36/1.21±0.31 vs. 1.14±0.20/1.07±0.17 µl left/right per g bw, p<0.05). Vice versa, after 8 weeks, cardiac masses, volumes, and output showed a trend for lower values in sham operated rats compared to controls in absolute measures (782.2±57.2/260.2±33.2 vs. 805.9±84.8/310.4±48.5 mg, p<0.05 for left/right ventricular mass), but not normalized to body weight. Matching these findings, blood testing revealed only minor inflammatory but prolonged metabolic changes after surgery not related to cardiac disease.

Conclusion

Cardio-thoracic surgical procedures in experimental myocardial infarction cause distinct alterations upon the global integrity of the organism, which in the long term also induce circumscribed repercussions on cardiac morphology and function. This impact has to be considered when analyzing data from respective animal studies and transferring these findings to conditions in patients.     

Farnesol Ameliorates Demyelinating Phenotype in a Cellular and Animal Model of Charcot-Marie-Tooth Disease Type 1A

Charcot-Marie-Tooth disease (CMT) is a genetically heterogeneous disease affecting the peripheral nervous system that is caused by either the demyelination of Schwann cells or degeneration of the peripheral axon. Currently, there are no treatment options to improve the degeneration of peripheral nerves in CMT patients. In this research, we assessed the potency of farnesol for improving the demyelinating phenotype using an animal model of CMT type 1A. In vitro treatment with farnesol facilitated myelin gene expression and ameliorated the myelination defect caused by PMP22 overexpression, the major causative gene in CMT. In vivo administration of farnesol enhanced the peripheral neuropathic phenotype, as shown by rotarod performance in a mouse model of CMT1A. Electrophysiologically, farnesol-administered CMT1A mice exhibited increased motor nerve conduction velocity and compound muscle action potential compared with control mice. The number and diameter of myelinated axons were also increased by farnesol treatment. The expression level of myelin protein zero (MPZ) was increased, while that of the demyelination marker, neural cell adhesion molecule (NCAM), was reduced by farnesol administration. These data imply that farnesol is efficacious in ameliorating the demyelinating phenotype of CMT, and further elucidation of the underlying mechanisms of farnesol’s effect on myelination might provide a potent therapeutic strategy for the demyelinating type of CMT.     

A组轮状病毒NSP1基因克隆表达及免疫学性质研究

轮状病毒（rotavirus, RV）非结构蛋白1（non structural protein 1, NSP1）在病毒与宿主的相互作用中发挥着重要的功能。运用基因克隆和表达技术在大肠杆菌中表达了TB-Chen株RV NSP1蛋白,进行了NSP1的免疫学性质和RV感染细胞中NSP1蛋白的合成与分布以及NSP1的系统进化和基因分型研究。结果表明,大肠杆菌BL21(DE3)能高效表达重组NSP1蛋白（rNSP1）,rNSP1表达量约占菌体总蛋白的34.4%。rNSP1能诱导免疫豚鼠产生特异性血清抗体。Western blot及免疫荧光检测结果表明,抗rNSP1血清抗体能特异性识别自身蛋白,对SA11、Wa株的NSP1蛋白有交叉反应性;免疫荧光结果还表明,SA11感染的MA104细胞中合成的NSP1蛋白在细胞质中区域化聚集形成辐射状排列的颗粒状结构,而Wa株的NSP1不能形成此样结构。至今发现的A组RV至少可以分为16个不同的NSP1基因型,TB-Chen株NSP1为A2型。不同基因型有独特的敏感宿主范围,同一基因型可能感染不同种动物,同一种动物也可能感染不同基因型。基因型A4型和A16型仅在鸟类病毒株中出现;而且鸟类中只有A4型和A16型。研究结果为进一步研究NSP1蛋白质的结构功能及其应用开发奠定了很好的基础。     

A组人轮状病毒NSP2基因的克隆、表达及免疫学性质研究

轮状病毒非结构蛋白NSP2在病毒基因组复制过程中起重要作用。在原核系统中重组表达了来自中国的第一株全基因组被克隆和研究了的轮状病毒NSP2,并进一步对其免疫学性质进行了研究。结果显示,在大肠杆菌中能够高效表达重组NSP2蛋白,而且该蛋白能够诱发豚鼠产生特异性抗体。Western blot和免疫荧光检测表明所得抗体不仅能与该重组NSP2蛋白发生特异性反应,而且可以与轮状病毒SA11株或Wa株感染的MA104细胞中表达的NSP2发生反应。以上这些结果为进一步研究该重组NSP2蛋白的结构、功能及免疫学性质奠定了基础.