展毛翠雀花中的二萜生物碱

从展毛翠雀花(Delphinium kamaonense var.glabrescens)中分离到两个C_(19)-二萜生物碱,经光谱方法确定结构,证明其中一个是新化合物,命名为展毛翠雀碱(glabredelphinine,Ⅰ)。另一个是已知生物碱tatsiensine(Ⅱ)。     

Survival pattern among infants born to human immunodeficiency virus type-1 infected mothers and uninfected mothers in Harare, Zimbabwe

OBJECTIVES: To determine the mother-to-child transmission (MTCT) rate of HIV-1 and to compare the survival patterns among infants born to HIV-1 infected and seronegative mothers. DESIGN: A two year prospective study from 1991 to 1995. METHODS: 345 HIV-1 infected mothers and 351 seronegative mothers and their infants were examined at regular intervals up to 24 months of age. RESULTS: The intermediate estimate of MTCT rate of HIV-1 was found to be 31.9%; (95% confidence interval (CI) 26.9 to 37.1). Of infants born to HIV-1 infected mothers 17% died compared with 2% of infants born to seronegative mothers. Forty six (43%) of the 107 HIV-1 infected infants died compared with 16 (219%) of the 559 uninfected infants. In a multivariate analysis, risk factors independently associated with infant mortality were low birth weight (hazard ratio (HR) 2.80; CI 1.52 to 5.13), HIV infected infant (HR 10.50; CI 5.48 to 20.15), HIV infected mother (HR 3.23; CI 3.17 to 15.85) and maternal death (HR 2.77; CI (1.09 to 7.06). CONCLUSION: The estimated MTCT rate of HIV-1 is comparable with rates of 25% to 45% reported from the African region. The poor survival of HIV-1 infected infants indicates the necessity for effective and comprehensive HIV/AIDS control strategies in Zimbabwe.     

Dose-dependent localization of TCDD in isolated centrilobular and periportal hepatocytes

Dose-response relationships for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suggest a differential sensitivity of liver cell types to the induction of cytochrome P450 gene expression, and that the induction of hepatic protein CYP1A2 causes sequestration of TCDD. In addition, immunolocalization of hepatic CYP1A1/1B1/1A2 proteins is not uniform after exposure to TCDD. The mechanism for the regio-specific induction of hepatic P450s by TCDD is unknown, but may involve the differential distribution of participants in the AhR-mediated pathway and/or regional P450 isozymes, as well as, non-uniform distribution/sequestration of TCDD. Therefore, this study examined the effects of TCDD in unfractionated, centrilobular and periportal hepatocytes isolated from female Sprague-Dawley rats acutely exposed (3 days) to a single oral dose of 0.01-10.0 microg [3H]TCDD/kg. A dose- dependent increase in concentration of TCDD was accompanied by a dose- dependent increase in CYP1A1, CYP1A2, and CYP1B1 mRNA expression and associated enzymes in all liver-cell populations. Centrilobular hepatocytes showed a 2.7- to 4.5-fold higher concentration of TCDD as compared to the periportal hepatocytes at doses up to 0.3 microg TCDD/kg. Centrilobular hepatocytes also exhibited an elevated MROD activity as compared to the periportal hepatocytes at doses up to 0.3 microg TCDD/kg. Furthermore, centrilobular hepatocytes showed an elevated concentration of induced CYP1A2 and CYP1B1 mRNA as compared to periportal hepatocytes within the 0.01- and 0.3-microg TCDD/kg- treatment groups. This is the first study to demonstrate that a dose- dependent difference in distribution of TCDD exists between centrilobular and periportal cells that might be related to regional differences in P450 induction.      

HLA-G and HLA-E polymorphisms in an indigenous African population. The ZVITAMBO Study Group

Studies of HLA-G and HLA-E polymorphisms in different populations from many industrialized countries have uniformly reported little sequence variation within these genes. To date, the polymorphism of these genes has not been characterized in populations from developing countries where more sequence variation would be anticipated due to greater exposure to microbial pathogens. In order to address this issue, we have recently investigated the polymorphism of these MHC genes in an indigenous African population (Shona ethnic group). HLA-G and HLA-E alleles were determined by PCR-restriction fragment length polymorphism (PCR-RFLP) and amplification refractory mutation system (ARMS) analysis in 108 unrelated women recruited from maternity clinics and hospitals in Harare (Zimbabwe). The genotyping analysis identified six different HLA-G alleles and three HLA-E alleles in this population. Of interest, the null-allele HLA-G*0105N was found with 11.1% of frequency, which is higher than in other populations tested so far. We observed the presence of 15 distinct HLA-G genotypes and 6 HLA-E genotypes. These data indicate that this African population contains low levels of allelic polymorphism similar to ethnic groups from industrialized countries. This is the first report describing HLA-G and HLA-E polymorphisms in an indigenous African population.     

Nebulized budesonide versus oral steroid in severe exacerbations of childhood asthma

The aim of this study was to assess whether nebulized budesonide may substitute for oral prednisolone in the management of children whose asthma is severe enough to warrant hospital admission, but who have no life threatening features. In a prospective, double-blind, randomized study nebulized budesonide (2 mg 8 hourly) was compared with oral prednisolone (2 mg/kg at entry and again at 24 h) in 46 children admitted to hospital with severe asthma exacerbations. Efficacy variables (including lung function measurements such as the primary outcome variable, Forced Expiratory Volume in 1 second (FEV₁) and symptoms) were measured 24 h after treatment initiation. FEV₁ improved significantly compared to baseline in patients who received nebulized budesonide compared to the prednislone group. The data show nebulized budesonide to be at least as effective as oral steroid in improving lung function and symptom severity in severe exacerbations of childhood asthma.