Severe acute respiratory syndrome (SARS) is caused by a novel and highly infectious virus named SARS coronavirus (SARS-CoV). Among the serological tests currently available for the detection of SARS-CoV, a whole-virus-based immunofluorescence assay (IFA) was considered one of the most sensitive assays and served as a "gold standard" during the SARS epidemic in Singapore in 2003. However, the need to manipulate live SARS-CoV in the traditional IFA limits its wide application due to the requirement for a biosafety level 3 laboratory and the risk of laboratory infection. Previously, we have identified two immunodominant epitopes, named N195 and Sc, in the two major structural proteins, the N and S proteins, of SARS-CoV (Q. He, K. H. Chong, H. H. Chng, B. Leung, A. E. Ling, T. Wei, S. W. Chan, E. E. Ooi, and J. Kwang, Clin. Diagn. Lab. Immunol., 11:417-422, 2004; L. Lu, I. Manopo, B. P. Leung, H. H. Chng, A. E. Ling, L. L. Chee, E. E. Ooi, S. W. Chan, and J. Kwang, J. Clin. Microbiol. 42:1570-1576, 2004). In the present study, the N195-Sc fusion protein was highly expressed in insect (Sf9) cells infected with a recombinant baculovirus bearing the hybrid gene under the control of a polyhedrin promoter. An IFA based on Sf9 cells producing the fusion protein was standardized with 23 serum samples from patients with SARS, 20 serum samples from patients with autoimmune diseases, and 43 serum samples from healthy blood donors. The detection rates were comparable to those obtained with a commercial SARS-CoV IFA kit (EUROIMMUN, Gross Groenau, Germany) and a conventional IFA performed at the Singapore General Hospital. Our data showed that the newly developed IFA could detect SARS-CoV in 22 of the 23 SARS-CoV-positive serum samples and gave no false-positive results when the sera from patients with autoimmune diseases and healthy individuals were tested. The detection rate was identical to those of the two whole-virus-based IFAs. Thus, the novel N-S fusion antigen-based IFA could be an attractive alternative to present whole-virus-based IFAs for the diagnosis of SARS-CoV infection. 相似文献
HLA-A2 subtypes (A*0201 - *0212) were determined by oligotyping in HLA-A2 positive samples from four populations (Han Chinese, Dai Chinese, Caucasoids from Germany and Turkish individuals from Kayseri)(see table).
Two different findings can be concluded from this study: 1) Significant HLA-A*02 allelic variations found in four populations. A*0207 is the predominant A*02 allele in the Dai population and absent in the German Caucasian and the Turkish population. In contrast, A*0201 is the most prevalent allele in the Caucasian, Turkish and Han Chinese group. We also found a high proportion of A*0206 and A*0207 in Han Chinese. 2) A strong association has been found between A*0207 and HLA-B46 and DR9 in the Dai minority population. This haplotype is also found in Han Chinese. Three DNA samples from Turkish and one from the Dai population are presently being sequenced because the reaction pattern was out of the expected (Supported by SFB 217) 相似文献
The results of several experimental studies of focal ischemia and anecdotal observations suggest that leukocytes may contribute to the injury initiated by an arterial occlusion. The timing and the nature of leukocyte responses in evolving brain infarcts (either human or experimental) are incompletely characterized. This is a study of experimental brain lesions in 96 Wistar rats that underwent occlusion of a large intracranial artery for variable intervals ranging between 30 minutes and 7 days. The experimental model, based on the occlusion of a middle cerebral artery ostium via the insertion of a nylon monofilament through the external carotid artery, does not require opening the skull; therefore, the inflammatory response is not influenced by the effects of craniotomy and changes in intracranial pressure are only those induced by the ischemic lesion. All 96 animals having the same type of arterial occlusion developed an ischemic brain lesion (limited to the territory of the corresponding artery) that evolved into an area of extensive neuronal necrosis over a period of 6 to 12 hours followed by pan-necrosis (infarct) approximately 60 hours later. In this study, leukocytes (in particular polymorphonuclear cells) were detected in the microvessels (capillaries and venules) of the ischemic hemisphere as early as 30 minutes after the arterial occlusion. Numbers of intravascular neutrophils peaked at 12 hours, whereas intraparenchymal granulocytes were most numerous at 24 hours; a few granulocytes were visible in the brain infarct as late as day 7. Circulating monocytes were first detected within the capillaries/venules of the ischemic area after 4 to 6 hours. Platelet aggregates were more abundant in the arterial than the venous side of the circulation, and luminal obstruction of arteries by platelet aggregates became noticeable only 48 hours after the arterial occlusion. Fibrin thrombi were conspicuous for their absence. These observations provide the background for studies that will attempt to unravel the relationship between the biological responses of leukocytes and neuronal necrosis secondary to focal ischemia. 相似文献
Thirty-four women bearing a levonorgestrel-releasing intrauterine device, 20 micrograms/day (LNG-IUD-20), for 12-15 months were recruited. Endometrial biopsies were collected during the late proliferative phase of the cycle (on cycle days 10-12) before (control) and after the use of the IUD for 12 months, and assayed for oestrogen receptors (ER) and progesterone receptors (PR). An immunohistochemical technique with the peroxidase-antiperoxidase detection system (PAP method) was employed. D75 and JZB39 were the primary antibodies for ER and PR respectively. The immunostaining semiquantitative analysis was performed with a computerized microscope image processor, and expressed as 'grey value'. Both endometrial ER and PR populations were significantly lower after insertion of the IUD (P < 0.01) than in control biopsies. The intensity of nuclear staining and the percentage of positively stained cells for ER and PR in women with LNG-IUD were each about 50% of those in control biopsies. The results suggested that LNG released locally from the IUD has a depressive action on the ER and PR, which may contribute to the contraceptive effectiveness of this type of IUD and also to the possible causes of LNG-IUD-induced irregular bleeding and amenorrhoea. 相似文献