Platelet interactions with viruses and parasites

Abstract

While the interactions between Gram-positive bacteria and platelets have been well characterized, there is a paucity of data on the interaction between other pathogens and platelets. However, thrombocytopenia is a common feature with many infections especially viral hemorrhagic fever. The little available data on these interactions indicate a similarity with bacteria-platelet interactions with receptors such as FcγRIIa and Toll-Like Receptors (TLR) playing key roles with many pathogens. This review summarizes the known interactions between platelets and pathogens such as viruses, fungi and parasites.     

Ebola Virus RNA Stability in Human Blood and Urine in West Africa’s Environmental Conditions

We evaluated RNA stability of Ebola virus in EDTA blood and urine samples collected from infected patients and stored in West Africa’s environmental conditions. In blood, RNA was stable for at least 18 days when initial cycle threshold values were <30, but in urine, RNA degradation occurred more quickly.     

Development and approval of live attenuated influenza vaccines based on Russian master donor viruses: Process challenges and success stories

Influenza is a viral infection that affects much of the global population each year. Vaccination remains the most effective tool for preventing the disease. Live attenuated influenza vaccine (LAIV) has been used since the 1950s to protect humans against seasonal influenza. LAIVs developed by the Institute of Experimental Medicine (IEM), Saint Petersburg, Russia, have been successfully used in Russia since 1987.In 2006, the World Health Organization (WHO) announced a Global action plan for influenza vaccines (GAP). WHO, recognizing potential advantages of LAIV over the inactivated influenza vaccine in a pandemic situation, included LAIV in the GAP.BioDiem Ltd., a vaccine development company based in Melbourne, Australia which held the rights for the Russian LAIV, licensed this technology to WHO in 2009. WHO was permitted to grant sub-licenses to vaccine manufacturers in newly industrialized and developing countries to use the Russian LAIV for the development, manufacture, use and sale of pandemic and seasonal LAIVs. To date, WHO has granted sub-licenses to vaccine manufacturers in China (Changchun BCHT Biotechnology Co., Ltd.), India (Serum Institute of India Pvt. Ltd.) and Thailand (Government Pharmaceutical Organization). In parallel, in 2009, IEM signed an agreement with WHO, under which IEM committed to supply pandemic and seasonal candidate vaccine viruses to the sub-licensees.This paper describes the progress made by collaborators from China, India, Russia and Thailand in developing preventive measures, including LAIV against pandemic influenza.     

须恙螨作为肾综合征出血热宿主的初步调查及实验研究

通过本次流行病学调查和实验研究，发现须恙螨主要分布于肾综合征出血热流行区，其地理分布与疫区的病例分布基本一致。主要传染源黑线姬鼠鼠体带螨指数为２５．１；从鼠肺抗原阳性鼠体所采集的须恙螨幼虫和小黑板采集经叮刺吸食已感染本病病毒的小白鼠乳鼠体液后的游离螨幼虫，分别分离到１株病毒，证明须恙螨具备传播媒介的先决条件。     

HSV-2W株对Vero细胞分裂指数影响的研究

HSV-2 W株感染Vero细胞后,对细胞的分裂指数可产生以下影响:在一定作用时间内,接种病毒的细胞其分裂指数高于对照细胞而低于接种秋水仙素的细胞;接种病毒最多的细胞高于接种病毒量少的细胞;但超过一定时间,则差别不显著;接种病毒时间长的细胞低于接种病毒时间短的细胞;接种灭活病毒的细胞高于接种未来灭活病毒的细胞。根据以上结果就HSV-2对宿主的某些生物学作用讲行了讨论。     

丙型肝炎患者PBMC的mIL-2R表达及其临床意义

目的 探讨丙型肝炎患mIL-2R表达水平及其临床意义。方法 用生物素-链酶亲和素法对56例抗-HCV阳性患外周血单个核细胞(PBMC)进行植物血凝素(PHA)诱导前后mIL-2R的的检测。结果 急、慢性丙型肝炎患静息状态mIL-2R表达水平，诱导状态mIL-2R表达水平分别与正常对照相比，差异均有显性。结论 丙型肝炎患体内存在明显的细胞免疫功能紊乱，T细胞活化障碍，并与肝病的慢性化有关。     

Changes in lymphocyte subset distribution aid in the differential diagnosis of renal allograft dysfunction

The distribution of selected lymphocyte subset populations in renal transplant patients was used to assist in the differential diagnosis of graft dysfunction. Patients experiencing dysfunction due to rejection showed consistent and significant decreases in relative numbers of CD 8 (cytotoxic/suppressor) lymphocytes. The ratio of CD 4 cells to CD 8 cells in this group of patients was generally greater than 2.00 due to decreases in CD 8 cells. Patients showing graft dysfunction due to viral infections showed consistent and significant increases in CD 8 cells which also bear the HNK-1 or the HLA-Dr determinants. Serial monitoring for these dual-marked lymphocytes on a weekly basis can be of considerable use in determining the etiology of graft dysfunction. Increases in other "activation" markers, including transferrin receptors, CD 38, and a T cell lineage specific activation antigen (TLiSA) were not specific for rejection; in fact, increases in CD38 were more often associated with viral infections. These studies indicated that lymphocyte subset determinations done on a regular basis can help distinguish graft dysfunction due to viral infections from other causes. The ability to distinguish rejection episodes from stable grafts is less obvious. Although the alterations in lymphocyte subset distribution are not entirely specific, they can distinguish viral infections from rejection.     

Transient GABA immunoreactivity in cranial nerves of the chick embryo

The distribution and time course of gamma-aminobutyric acid (GABA) immunoreactivity was investigated in the cranium of the chick embryo from 2 to 16 days of incubation (E2-16). A fraction of nerve fibers transiently stains GABA-positive in all cranial motor nerves and in the vestibular nerve. Cranial motor nerves stain GABA-positive from E4 to E11, including neuromuscular junctions at E8-11; labeled fibers are most frequent in the motor trigeminal root (E6-9.5). Substantial GABA staining is present from E4 to E10 in a subpopulation (1-2%) of vestibular ganglion cells. Their peripheral processes are labeled in the vestibular endorgan, predominantly in the posterior crista. Some GABA-positive fibers are present in the olfactory nerve (after E5) and in the optic nerve (after E9.5); their immunoreactivity persists throughout the period investigated. Transient GABA immunoreactivity follows "pioneer" fiber outgrowth and coincides with the formation of early synaptic contacts. GABA-containing neurons may change their neuronal phenotype (loss of GABA expression) or they may be eliminated by embryological cell death. Periods of cell death were determined in cranial ganglia and motor nuclei by aggregations of pycnotic cells in the same embryonic material. The periods of embryonic cell death partly coincide with transient GABA immunoreactivity. The function(s) of transient GABA expression is unknown. Some lines of evidence suggest that GABA has neurotrophic functions in developing cranial nerves or their target tissue. In the developing neuromuscular junction, GABA may be involved in the regulation of acetylcholine receptors.     

Currently used nucleic acid amplification tests for the detection of viruses and atypicals in acute respiratory infections

For the detection of respiratory viruses conventional culture techniques are still considered as the gold standard. However, results are mostly available too late to have an impact on patient management. The latest developments include appropriate DNA- and RNA-based amplification techniques (both NASBA and PCR) for the detection of an extended number of agents responsible for LRTI. Real time amplification, the latest technical progress, produces, within a considerable shorter time, results with a lower risk of false positives. As results can be obtained within the same day, patient management with appropriate therapy or reduction of unnecessary antibiotic therapy in LRTI will be possible. A number of technical aspects of these amplification assays, and their advantages are discussed.The availability and use of these new diagnostic tools in virology has contributed to a better understanding of the role of respiratory viruses in LRTI. The increasing importance of the viral agents, Mycoplasma pneumoniae and Chlamydophila pneumoniae in ARI is illustrated. A great proportion of ARI are caused by viruses, but their relative importance depends on the spectrum of agents covered by the diagnostic techniques and on the populations studied, the geographical location and the season. The discovery of new viruses is ongoing; examples are the hMPV and the increasing number of coronaviruses. Indications for the use of these rapid techniques in different clinical situations are discussed. Depending on the possibilities, the laboratory could optimize its diagnostic strategy by applying a combination of immunofluorescence for the detection of RSV an IFL, and a combination of real-time amplification tests for other respiratory viruses and the atypical agents. When implementing a strategy, a compromise between sensitivity, clinical utility, turn around time and cost will have to be found.