基于1H-NMR植物代谢组学技术分析青海产区枸杞子的化学特征

目的:采用核磁共振氢谱(~1H-NMR)植物代谢组学技术比较青海产区枸杞子与其他产区(宁夏、甘肃、新疆、内蒙古)枸杞子的化学成分差异。方法:收集5个产区共97份枸杞子样本,其中青海61个样本,采用50%甲醇提取,检测~1H-NMR图谱,结合多元统计分析,对比青海产区枸杞子与其他产区枸杞子的化学差异性,并对各产区样本的枸杞多糖进行含量测定(以无水葡萄糖计),检测波长490 nm。结果:枸杞子的~1H-NMR图谱共检测到32个化学成分,多元统计分析表明青海产区枸杞子与其他产区样本相比,无明显分离趋势;青海产区枸杞子与宁夏产区相比,以及青海省6个不同地区的枸杞子相比,重叠样品较多,均不能显著分开。相似度结果表明,大多数样品的相似度0.85;化合物的单变量分析结果显示,除了蔗糖、葡萄糖、脯氨酸等个别代谢物在各产区样本中存在显著差异外,其余代谢物在各产区样品中的含量分布基本一致。青海与其他产区样本中枸杞多糖含量无显著性差异,且枸杞多糖含量与~1H-NMR指认的小分子化合物的相关系数处于-0.2～0.4。结论:采用~1HNMR植物代谢组学技术从整体化学组成上分析了青海产区枸杞子的化学特征,并结合枸杞多糖含量测定,显示青海产区枸杞子与其他产区枸杞子的化学差异较小。建立的基于~1H-NMR的枸杞子质量评价方法可为其质控水平提升及种植产区选择提供科学依据。     

Endoscopic ultrasonography guided drainage:Summary of consortium meeting,May 21,2012,San Diego,California

Endoscopic retrograde cholangiopancreatography(ERCP) is the preferred procedure for biliary and pancreatic drainage.While ERCP is successful in about 95% of cases,a small subset of cases are unsuccessful due to altered anatomy,peri-ampullary pathology,or malignant obstruction.Endoscopic ultrasound-guided drainage is a promising technique for biliary,pancreatic and recently gallbladder decompression,which provides multiple advantages over percutaneous or surgical biliary drainage.Multiple retrospective and some prospective studies have shown endoscopic ultrasoundguided drainage to be safe and effective.Based on the currently reported literature,regardless of the approach,the cumulative success rate is 84%-93% with an overall complication rate of 16%-35%.endoscopic ultrasoundguided drainage seems a viable therapeutic modality for failed conventional drainage when performed by highly skilled advanced endoscopists at tertiary centers with expertise in both echo-endoscopy and therapeutic endoscopy     

Oral ulceration in HIV infection: Investigation and pathogenesis

Oral ulcerations associated with HIV infection include recurrent aphthous ulcers (RAU). Whereas RAU prevalence is not increased, lesion severity is: among a group of HIV⁺ patients, 66% had the more severe herpetiform or major RAU. This increased severity suggests that HIV disease-related changes in the immune system may exacerbate RAU. In the peripheral blood of healthy subjects with RAU, CD4:CD8 cell ratios may be reversed and the proportion of T cell receptor-γδ⁺ cells increased. HIV disease-related immune system changes are characterized by reversed CD4:CD8, lowered CD4 cell counts and an inverse correlation between CD4 cell counts and per cent activated γδ lymphocytes. Adhesion molecules and cytokines involved in lymphocyte homing may be important in RAU pathogenesis: ICAM-I and ELAM are strongly expressed, and TNFα production is increased in peripheral blood lymphocytes of healthy patients with RAU. In patients with active HIV disease/AIDS, serum TNFα levels are increased. Thalidomide, which inhibits TNFα production, is effective treatment for RAU. Some RAU patients have vitamin B12 or folate deficiencies, levels of which are commonly low in HIV⁺/AIDS patients. However, in a case control study of HIV⁺ patients, vitamin B12- or folate-deficiencies were not found to be significant risk factors for RAU.     

Epstein-Barr virus BMRF-2 and BDLF-3 expression in hairy leukoplakia

Hairy leukoplakia (HL) is a lesion found on the side of the tongue of immunocompromised individuals, including those with human immunodeficiency virus (HIV) infection. The lesion has unique histopathologic features and is characterised by high-level Epstein-Barr virus (EBV) replication, multiple EBV strains, and extensive inter-and intra-strain recombination. Expression of EBV genes spanning the entire viral life cycle from latency-associated genes to late, replicative genes has been detected in the lesion. HL thus provides a unique opportunity to study EBV expression in oral epithelium, and to study expression of novel EBV genes. We therefore constructed a cDNA library from an HL biopsy and detected expression of two genes not previously described in vivo: BMRF-2 and BDLF-3. Sequence analysis of the cDNAs revealed few amino acid changes from the B95-8 sequence. Expression of both genes was localized to the lower prickle cell layer of the tongue epithelium. BMRF-2 protein expression was primarily detected in the cell nuclei of the upper prickle cell layer. BDLF-3 protein expression was observed in the perinuclear space and Golgi compartment. The function of these proteins is currently under investigation.     

Memory B cells at successive stages of differentiation. Affinity maturation and the role of IgD receptors

The following evidence, mainly presented here, suggests that IgD receptors play a crucial role in determining the potential for affinity maturation in memory B cell populations. IgD receptors are present on the first memory B cells to appear after priming. These memory cells give rise to more-mature memory cells that have lost their IgD receptors. The proportions of early (IgD(+)) and mature (IgD(-)) memory cells found in individual donors vary with time, priming conditions, and the availability of T cell help, and both populations frequently coexist for long periods of time. IgD(+) and IgD(-) memory cells carry IgG receptors and give rise to IgG responses with identical isotype representation in adoptive recipients. IgD(+) memory cells, however, always give rise to predominantly low-affinity antibody responses, whereas IgD(-) memory cells consistently generate responses of substantially higher average affinity. This affinity differential is maintained between early and mature memory populations in the same donor and does not appear to be a result of selective differentiation of higher-affinity IgD(+) memory cells into the IgD(-) memory pool. Thus, the selective forces responsible for affinity maturation appear to operate mainly in mature memory cell populations that have already lost IgD receptors; or, stated conversely, little or no selection towards high-affinity memory appears to occur among memory cells that retain IgD receptors. In discussing these findings, we suggest that the IgD receptors themselves are responsible for maintaining early memory populations at a lower average affinity than IgD(-) populations in the same animal. The IgD receptors, we argue, serve to increase the antigen-binding capacity of lower-affinity memory cells so that these cells can survive, expand, and differentiate (to IgD(-)) at antigen concentrations that select against expansion of low- affinity memory cells no longer carrying IgD receptors. Thus, when antigen is limiting, IgD(-) memory populations will be selectively expanded to higher average affinities, whereas coexisting IgD(+) populations will retain their initial affinity profile. This hypothesis suggests that mechanisms that regulate expression and loss of IgD receptors are central to the adaptability of the immune system in its response to invading pathogens. Two related roles can be envisioned for the IgD receptors in this regard. First, they extend the lower boundary of the affinity range of early memory cell populations induced by a given antigenic stimulus and therefore broaden the diversity of responses obtainable from these populations. Secondly, they support the persistence of low-affinity memory populations under conditions where antigen becomes limiting and eventually disappears. These persisting populations then serve as a diversely reactive reservoir from which mature memory populations can be drawn with higher affinities either for the original antigen or, more importantly, for related antigens that the animal may subsequently encounter. Thus the existence of IgD receptors on early memory cells maintains the full range of response diversity despite ongoing selective expansion of (mature) memory populations to produce antibodies with high combining affinities for individual antigens. The flexibility inherent in such an organizational system, we believe, could be expected to account for the evolutionary development of IgD receptors and the regulatory capabilities that support operation of the system.     

Enhanced Bone Regeneration Using Porcine Small Intestinal Submucosa

Small instestinal submucosa (SIS) is an easily produced material that has been used experimentally for tissue engineering. To evaluate the ability of SIS to facilitate bone growth within a long-bone defect, a segment of the radius was surgically removed in adult, female Sprague-Dawley rats. The defect was either left unfilled or implanted with SIS, demineralized cortical bone (DMCB), or ovalbumin. The defect was evaluated radiographically and histologically after 3, 6, 12, and 24 weeks. Tissue remodeling within the defect was evident by week 3 in SIS- and DMCB-treated rats. Filling was characterized initially by infiltration of mononuclear cells and extracellular material in SIS-implanted rats and multifocal remodeling bone particles and cartilage formation in DMCB implanted rats. Cartilage was observed as early as 3 weeks and bone as early as 6 weeks in SIS-implanted rats. Filling of the defect arose from multiple foci in DMCB-implanted rats, but was contiguous with and parallel to the ulnar shaft in SIS-implanted rats, suggesting that defect repair by SIS may be conductive rather than inductive. Rats in which the defect was left unfilled demonstrated slow but progressive filling of the defect, characterized by mononuclear cell infiltrates and fibrous extracellular material. In summary, SIS facilitated rapid filling of a longbone defect. These results suggest that SIS may be useful as a bone repair material.