Genetic analysis of hantaviruses and their rodent hosts in central-south China

Hantaan virus (HTNV) and Seoul virus (SEOV) are two major zoonotic pathogens of hemorrhagic fever with renal syndrome (HFRS) in Asia. Hubei province, which is located in the central-south China, had been one of the most severe epidemic areas of HFRS. To investigate phylogenetic relationships, genetic diversity and geographic distribution of HTNV and SEOV in their reservoir hosts, a total of 687 rodents were trapped in this area between 2000 and 2009. Sequences of partial S- and M-segments of hantaviruses and mitochondrial D-loop gene from 30 positive samples were determined. Our data indicated that SEOV and HTNV were co-circulating in Hubei. Phylogenetic analysis based on partial S- and M-segment sequences revealed two and three previously undefined lineages of SEOV, and a novel genetic lineage of HTNV, respectively. Four inter-lineage reassortment SEOVs carried by Rattus norvegicus and Apodemus agrarius were observed. It suggests that SEOV may cause spillover infections to A. agrarius naturally. The abundance of the phylogenetic lineages of SEOV suggested that central-south China was a radiation center for SEOVs.     

B‐cell co‐receptor CD72 is expressed on NK cells and inhibits IFN‐γ production but not cytotoxicity

NK cells have two main functions, namely cell‐mediated cytotoxicity and production of cytokines. Multiple inhibitory receptors that regulate NK‐cell cytotoxicity have been characterized whereas little is known about receptors regulating cytokine production. Here we report that CD72, which is considered to be an important co‐receptor regulating B‐cell activation, is also expressed on mouse NK cells. NK cells expressing high levels of CD72, upon stimulation with IL‐12 and IL‐18 or target cells, produce significantly less IFN‐γ than those expressing low levels of CD72, whereas both subsets are equally cytotoxic. Ectopic expression of CD72 in the murine NK‐cell line KY2 inhibits cytokine‐induced IFN‐γ production, and the inhibitory effect is diminished by mutations in the inhibitory motifs in the intracellular domain or replacement of the extracellular domain of CD72. Thus, CD72 is an inhibitory receptor on NK cells regulating cytokine production.     

Effector T‐cell differentiation during viral and bacterial infections: Role of direct IL‐12 signals for cell fate decision of CD8+ T cells

To study the role of IL‐12 as a third signal for T‐cell activation and differentiation in vivo, direct IL‐12 signaling to CD8⁺ T cells was analyzed in bacterial and viral infections using the P14 T‐cell adoptive transfer model with CD8⁺ T cells that lack the IL‐12 receptor. Results indicate that CD8⁺ T cells deficient in IL‐12 signaling were impaired in clonal expansion after Listeria monocytogenes infection but not after infection with lymphocytic choriomeningitis virus, vaccinia virus or vesicular stomatitis virus. Although limited in clonal expansion after Listeria infection, CD8⁺ T cells deficient in IL‐12 signaling exhibited normal degranulation activity, cytolytic functions, and secretion of IFN‐γ and TNF‐α. However, CD8⁺ T cells lacking IL‐12 signaling failed to up‐regulate KLRG1 and to down‐regulate CD127 in the context of Listeria but not viral infections. Thus, direct IL‐12 signaling to CD8⁺ T cells determines the cell fate decision between short‐lived effector cells and memory precursor effector cells, which is dependent on pathogen‐induced local cytokine milieu.     

用毒饵盒投放急慢性毒饵灭家栖鼠类研究

目的观察在毒饵盒中投放急慢性毒饵灭家栖鼠类及对小家鼠和褐家鼠的灭鼠效果。方法选择济南市历城区西彩石村,每间房间布放毒饵盒1个,内放0.5%毒鼠磷和0.05%敌鼠钠整粒小麦。急性药剂毒饵盒放50g,慢性药剂毒饵盒放100g,每组90户;效果考核S100格法。结果急性药剂毒饵盒5、10、15、20d总灭鼠率分别为77.54%、82.36%、88.50%和93.78%;针对小家鼠灭效分别为76.81%、82.83%、88.92%和94.14%,褐家鼠灭效分别为100%、68.29%、75.61%和80.49%。慢性药剂毒饵盒10、20、30、60d总灭鼠率分别为90.93%、93.17%、98.11%和98.28%;针对小家鼠灭效分别为91.12%、93.24%、98.18%和98.24%,对褐家鼠灭效分别为80.95%、92.86%、95.24%和100%。慢性药剂毒饵盒第10天总灭鼠效果优于急性药剂毒饵盒（u=11.43,P〈0.01）。结论慢性抗凝血灭鼠剂毒饵盒灭鼠效果显著。     

广西流行性出血热疫区类型及流行病学特征

目的研究和掌握广西流行性出血热疫区类型及流行病学特征。方法收集20年来广西流行性出血热的发病数据,对疫区分布及其流行强度进行分析。用夹夜法在室内及室外布夹,对捕获的宿主动物无菌取血清及肺组织,用酶联免疫吸附法（ELISA）检测血清汉坦病毒抗体及肺组织中的抗原,汉坦病毒抗原阳性的标本采用逆转录-聚合酶链反应（RT-PCR）鉴定并测序,将扩增片段的核苷酸序列与已知病毒序列进行比对分型。结果1990~2009年广西流行性出血热累计报告病例数为286例,男性农村青壮年多发,总体上发病水平较低,以邻近湖南省的桂北局部地区多见,近年来城市发病例数有增多趋势。2006~2008年共监测捕获啮齿动物18种共1 984只,褐家鼠为优势种,宿主动物感染汉坦病毒总抗体阳性率为14.75%;宿主动物肺组织抗原阳性6份,经核酸检测和测序证实为Ⅱ型病毒（汉城型汉坦病毒）。结论广西流行性出血热的宿主动物以褐家鼠为优势种,多种宿主动物感染汉坦病毒,从褐家鼠肺组织标本可检测出Ⅱ型病毒,疫区类型以Ⅱ型病毒（汉城型汉坦病毒）为主;广西EHF发病水平较低,以男性农村青壮年多发,邻近湖南省的桂北局部地区为高发地区,近年城市发病有增多趋势。     

Endoparasites of Rodents and Their Zoonotic Importance in Germi,Dashte–Mogan,Ardabil Province,Iran

Background

In order to verify the infectivity of rodents with endoparasites in Germi (Dashte-Mogan, Ardabil Province) the current study was undertaken.

Methods

Using live traps, 177 rodents were trapped during 2005–2007. In field laboratory, all rodents were bled prior to autopsy, frozen at −20°C, and shipped to the School of Public Health, Tehran University of Medical Sciences, Iran. In parasitological laboratory, every rodent was dissected and its different organs were examined for the presence of any parasite. Blood thick and thin smears as well as impression smears of liver and spleen were stained with Geimsa and examined microscopically.

Results

Two species of rodents were trapped; Meriones persicus (90.4%) and Microtus socialis (9.6%). The species of parasites found in M. persicus and their prevalences were as follows: Hymenolepis diminuta (38.8%), Hymenolepis nana (2.5%), Trichuris sp.(40.6), Mesocestoides larva (=tetrathyridium) (3.1%), Capillaria hepatica (6.9%), Moniliformis moniliformis (11.3%), Syphacia obvelata (2.5%), Taenia endothoracicus larva (0.6%), Physaloptera sp. (0.6%), Dentostomella translucida (0.6%), Heligmosomum mixtum (0.6%), Strobilocercus fasciolaris (0.6%),and Aspiculuris tetraptera (0.6%). The species of parasites found in M. socialis and their prevalences were as follows: H. diminuta (17.6%), Trichuris sp. (5.9%), Mesocestoides larva (5.9%), S. obvelata (11.8%), S. syphacia (11.8%), H. mixtum (17.6%), and Aspiculuris tetraptera (11.8%). There were no statistical differences between male and female for infectivity with parasites in either M. persicus or M. socialis. No blood or tissue protozoan parasite was found in any of the rodents examined.

Conclusion

Among different species identified, some had zoonotic importance. Therefore, the potential health hazard of these species needs to be considered to prevent infectivity of humans.     

A balanced brain asymmetry modulates T cell-mediated events

Partial ablation of the left fronto-parietal cerebral cortex decreases the number of spleen T cells, impairs IgG-alpha SRBC and T mitogen-induced responses, and delays the response to alloantigens. In contrast, these events are increased following a symmetric lesion of the right neocortex. The findings extend previous results showing that the neocortex modulates NK activity and the efficacy of T cell-specific serum factors. B cells and macrophages are not affected. In these assays, mice subjected to ablation of one lateral cerebral neocortex serve as controls for symmetrically lesioned mice, in addition to no surgery or sham-operated controls. The findings suggest that brain lateralization for cognitive processes should be extended to T cell immune recognition. The phenomenon is present at a population level.     

Mirtazapine enhances the effect of haloperidol on apomorphine-induced climbing behaviour in mice and attenuates haloperidol-induced catalepsy in rats

 Activation of 5-HT_1A receptors has been shown to attenuate catalepsy induced by typical antipsychotic compounds. Since mirtazapine (Remeron; Org 3770) has indirect 5-HT_1A receptor stimulating properties as well as antagonist properties at α₂-adrenoceptors and 5-HT₂ receptors, it was of interest to investigate how the compound could modulate the effect of haloperidol on apomorphine-induced climbing behaviour in mice and haloperidol-induced catalepsy in rats. In the apomorphine climbing test, it was found that mirtazapine (2.2–22 mg/kg) did not change the climbing behaviour of mice induced by 1 mg/kg of apomorphine. However, when given as a co-treatment with haloperidol, mirtazapine (1 and 10 mg/kg) dose-dependently augmented the inhibiting effect of haloperidol on this climbing behaviour. Co-treatment with the 5-HT_1A receptor agonist 8-OH-DPAT (0.1 mg/kg) also augmented the effect of haloperidol. Catalepsy induced by haloperidol (4.6 mg/ kg) was attenuated by mirtazapine (2.2–22 mg/kg). The strongest effect was seen at 90 min after haloperidol treament. The results obtained in these experiments suggest that co-treatment with mirtazapine may enhance the antipsychotic effect of haloperidol and reduce its extrapyramidal side effects, thereby widening its therapeutic window. Received: 6 May 1997/Final version: 10 August 1997     

Organ xenografting between rodents: an evolutionary perspective

Rejection times of heart xenografts in several donor-recipient combinations including the guinea pig, rat, hamster, and mouse are examined in light of the paleontological history of rodents and the resulting phylogenetic distances between taxa. This multidisciplinary review at the molecular, chromosomal and morphological levels suggests that xenograft rejection time is inversely proportional to the time divergence or phylogenetic distance, and that the binomial terminology concordant/discordant does not reflect the amplitude of phylogenetic distances.     

Expression of blood group-related glycoconjugates in the junctional and other oral epithelia of rodents

Background: The junctional epithelium (JE) attaches the gingiva to the non-vital tooth surface and has other unusual properties which protect the underlying periodontal tissues. The JE differs from other gingival and oral epithelia in its unusual expression of cytokeratins typical of both stratifying and of simple èpithelia, a phenotypic pattern possibly related to its specialized functions. Methods: The patterns of differentiation of rodent gingival and other epithelia were examined using monoclonal antibodies against various glycoconjugates which are expressed on epithelial cell surfaces and provide an alternative marker system for regionally-differing patterns of cell maturation. Results: Markers that are typical of basal cells in other stratifying epithelia were expressed by all cell strata of JE. JE lacked differentiation markers typical of other stratifying oral epithelia but showed suprabasal expression of markers typically expressed by simple epithelia and specialized epithelia, such as taste buds. Conclusions: The phenotype of rodent JE differs from that of other oral epithelia and the pattern of differentiation assessed by its expression of glycoconjugates parallels that for other phenotypic markers, such as cytokeratins. Differentiation of rodent JE is similar to that of human JE. The functional significance of these patterns of expression is not yet clear but the markers characterizing this unusual epithelium in rodents may be associated with its behavior in periodontal disease and of value to experimental studies of its development.© 1995 Wiley-Liss, Inc.