Use of class II tetramers for identification of CD4+ T cells

Multivalent MHC class II molecules containing peptide antigens are useful tools for the detection of antigen specific human CD4+ T cells. Tetramers produced by exogenous peptide loading onto empty class II molecules are comparable to tetramers with peptide tethered to the class II chain covalently, but have many practical advantages. Conditions for optimal peptide loading to generate tetramers are discussed and optimal conditions of using tetramers for staining T cells are examined. As the frequency of antigen specific CD4+ T cells in peripheral blood is low, we demonstrate that an in vitro expansion step is effective in detecting low frequency T cells. Two new applications with tetramers, their uses for mapping T cell epitopes and for the detection of low affinity T cells are described. In a clinical setting, potential applications include using these reagents for monitoring disease progression during clinical intervention.     

围产儿羊水吸入性肺炎发病学探讨：172例多因素逐步回归研究

对1980.9～1982.8江苏省6个城市172例围产儿羊水吸入性肺炎临床病理多因素回归分析研究,以探讨其发病机制。目的是筛选能影响肺炎和羊水吸入的临床参数。结果:(1)男婴占52.91%,女婴47.09%。(2)组织学:肺的炎症和羊水大多数是混合性、弥漫性分布,病变较一致,纤维素渗出很少,这说明本病可能是在出生前或分娩过程中吸入感染的羊水所致。(3)影响本病发生的主要因素为剖腹产、胎吸术、羊水吸入以及胎龄。(4)影响羊水吸入性的因素为胎儿体重(4000g以上)和胎龄(42周以上)。而体重、胎龄和胎吸术又和产程延长有关。     

Integrated medical informatics with small group teaching in medical education

National Taiwan University College of Medicine (NTUCM) introduced small groups of teaching and basic-clinical integrated courses for medical students in 1992. By using computer network and multimedia techniques, this study tried to overcome barriers to learning in small group teaching. The Department of Medical Informatics of NTUCM established campus networking and computer classrooms and provided Internet and intranet network services including mail, netnews, bulletin board systems (BBS), world wide web (WWW), gopher, ftp and local file servers. To implement an interactive learning environment, the authors first tried mail lists, newsgroups and BBS. Next an integrated learning system prototype on the WWW was developed to provide functions including online syllabus, discussion boards simulated to BBS, online talk, interactive case studies, virtual classroom with video on demand (VOD) and Internet medical resources. The results showed that after the medical students completed the required course of medical informatics and had good network access using a network to communicate with each other became a daily practice. In the future, the system will extend to the tutoring of clinical practice and continuing medical education. The authors expect a national medical education network and more international cooperation and exchange.     

Computer analysis system of blood oxygen saturation in an animal hypoxia model

An experimental animal hypoxia model has been developed. It consists of two sensors (an in vitro and in vivo model), an experimental device and a computer signal processing system. This method can easily be applied to determine and analyse blood oxygen saturation at various hypoxia levels. It can also be used to evaluate the accuracy of pulse oximetry over a wide range of oxyhemoglobin desaturation levels. The DC and AC components of recorded red and infra-red signals, the dual-wavelength ratio R₁₂ and the reading of a pulse oximeter (SpO₂) can be automatically calculated and displayed on a computer screen. Preliminary results of the animal hypoxia test indicate that the measurements made by the instrument correlate well with the oxygen saturation readings of the automatic blood gas analyser AVL945. The computer analysis system is suitable for repeated estimations in the animal model.     

The primary and secondary pathological changes in the brain in patients with epidemic hemorrhagic fever

Pathological changes of brain in 12 patients died of epidemic hemorrhagic fever were analysed. Those cases having clinical history of hypotension and typical shock showed ischemic changes and necrosis of brain and its seguelae accompanying synchronous with infarct-like necrosis of the kidneys or pituitary gland (secondary change). One patient who died in the febrile stage showed scattered necrosis of nerve cells with neuronophagia (primary change). Immunocytochemical study on one recent case showed diffusely distributed positive virus antigen in neurons and glial cells of various kinds and even occasional positive reaction was seen in the nuclei.     

Genetic basis for conversion of rough-to-smooth colony morphology in Actinobacillus actinomycetemcomitans

The basis of the rough-to-smooth conversion of Actinobacillus actinomycetemcomitans was examined. Smooth variants often contained mutations at the flp promoter region. Replacing the mutated flp promoter with the wild-type promoter restored the rough phenotype. The expression level of the flp promoter was approximately 100-fold lower in smooth than in rough strains. Mutations of the flp promoter are a cause of the rough-to-smooth conversion.     

Transgenic rabbits with increased VEGF expression develop hemangiomas in the liver: a new model for Kasabach-Merritt syndrome

Clinical studies have provided ample evidence that high (either systemic or local) levels of vascular endothelial growth factor (VEGF) are associated with several pathophysiological disorders, including hemangiomas. To investigate whether elevated VEGF expression could directly affect these disorders, we created a transgenic (Tg) rabbit model with increased hepatic expression of the human VEGF(165) transgene under the control of the human alpha-antitrypsin promoter. Tg rabbits exhibited marked hepatomegaly, with livers 2.5-fold heavier than those of control rabbits. Histological analysis revealed that the livers of Tg rabbits showed prominent dilation of the sinusoids and formed various-sized blood vessel networks, a feature of diffuse hemangiomas. Immunohistochemical staining revealed that the hepatocytes produced VEGF(165), whereas plasma VEGF(165) was not detected. Furthermore, Tg rabbits suffered from hemolytic anemia, thrombocytopenia and splenomegaly, which was associated with marked extramedullary hematopoiesis. The manifestations of Tg rabbits mimic many of the features of hemangiomatous disorders in humans such as the Kasabach-Merritt syndrome, and therefore this model may be potentially useful for the study of the pathogenesis and complications of hemangiomas as well as the investigation of angiogenesis inhibitors.     

Monoclonal antibodies recognizing EVETPIRN epitope of influenza A virus M2 protein could protect mice from lethal influenza A virus challenge

Based on the fact that the 24 amino acid extracellular domain of M2 protein (M2e) is nearly invariant in all influenza A strains, several different M2e vaccine constructs and vaccination modalities have been developed by others and us. Although most of these vaccines could induce efficient and broad-spectrum immunity inhibiting influenza A virus infection in mice model, information of the refined protective epitope on M2e was scarce. In this paper, two M2e specific monoclonal antibodies (mAbs) conferring protective immunity in vivo were reported, which in passive administration could protect 75% mice from five LD(50) (50% lethal dose) challenge of influenza virus A/PR/8/34. In addition, higher M2e specific antibody titer (over 1:1600) could be detected after 12h of intraperitoneal passive administration in mice sera. Peptide mapping assay indicated that both mAbs strongly interacted with N-terminus and middle part peptides of M2e (NM2, aa2-12; MM2, aa8-18), but not with the C-terminus peptide (CM2, aa13-24). More importantly, M2e specific mAbs could recognize EVETPIRN (aa6-13) peptide, which were the overlapping region of NM2 and MM2 peptide and the neighboring amino acid residues. In contrast, M2e domain that was deleted EVETPIR sequence could not be recognized by either mAb in immunoblotting assay. All these results indicated that the epitope EVETPIRN (aa6-13) on M2e could be responsible for the induction of the protective immunity.