大鼠创伤性脑损伤后神经细胞凋亡的动态变化及其与caspase-3基因表达的关系

目的 探讨创伤性脑损伤(TBI)后神经细胞凋亡的变化规律及其与caspase-3基因表达的关系.方法 成年健康封闭群SD大鼠120只,随机分为对照组8只、损伤组和抑制物组各56只.Feeney法致伤,抑制物组伤后脑内注射5μg caspase-3抑制剂z-DEVD-fmk.分别在伤后1,6,24,48 h和3,7,14 d处死取材(每个分析时相点8只大鼠),采集伤灶中心皮质、皮层下白质、海马、齿状回,以及对侧相应部位脑组织,应用原位末端脱氧核糖核酸转移酶介导的脱氧尿苷三磷酸(dUTP)标记法(TUNEL法)和流式细胞术检测神经细胞凋亡的变化;免疫组化法、蛋白印迹(western blot)和半定量逆转录-聚合酶链式反应(RT-PCR),检测caspase-3蛋白和mRNA的表达;并借助荧光分析试剂盒检测caspase-3活性的变化.所得数据采用SIDSS 10.1统计软件包进行Sprarman等级相关分析和方差分析(sNK-α检验).结果 伤后伤侧各脑区神经细胞凋亡指数(AI)和细胞凋亡百分率(AP)迅速增高,24～48 h达峰值,随后逐渐下降,但伤后14 d仍高于正常(P＜0.01).伤后caspase-3蛋白和mRNA的表达明显增加,caspase-3活性迅速上升,峰值在24～48 h.其中伤后24 h伤侧海马区caspase-3蛋白谱密度与对照组相比增加1484%,caspase-3 mRNA的表达量增加1043%,caspase-3活性增加148%;伤后48h伤灶皮层下白质caspase-3蛋白谱密度增加1690%,caspase-3 mRNA的表达量增加1181%,caspase-3活性增加183%.Western blot显示,伤后caspase-3原酶及p17活性亚单位的表达均增强.抑制物组caspase-3蛋白和mRNA的表达均明显下降,caspase-3活性明显降低;同时,AI值和AP值也明显降低.统计学相关分析发现.伤后神经细胞凋亡与caspase-3 mRNA和蛋白的表达间呈正相关(r=0.821和r:0.638,P＜0.01),伤后caspase-3在mRNA和蛋白水平的表达间呈正相关(r=0.945,P＜0.01).结论 急性TBI后神经细胞凋亡的发生与caspase-3的激活有关;神经细胞凋亡与其调节基因caspase-3的表达间具有一致性,TBI对caspase-3的调节发生在转录水平前的某一环节.caspase-3抑制剂能有效地阻断TBI后的神经细胞凋亡.     

Development of day-8 colony-forming unit-spleen hematopoietic progenitors during early murine embryogenesis: spatial and temporal mapping

The ontogeny of the hematopoietic system in mammalian embryos occurs during the yolk sac (YS) and the fetal liver (FL) stages. Events leading to the establishment of hematopoiesis in the FL remain obscure. The appearance of colony-forming units-spleen (CFU-S) in the FL is preceded by a gradual increase of CFU-S in the YS and a more rapid increase in the AGM region (area comprising dorsal aorta, gonads, and mesonephros) during day 10 of development (Medvinsky et al, Nature 364:64, 1993). By this time, the AGM CFU-S attain a high frequency equivalent to that found in the adult bone marrow. The analogous area gives rise to adult hematopoiesis in amphibians and probably in birds. We present here a more complete picture of CFU-S development during transition from the pre-liver to liver stage of hematopoiesis. (1) Dissectional analysis of the mouse AGM region shows the presence of CFU- S both around the dorsal aorta and in the uro-genital ridges. (2) The embryonic gut also shows low but distinctive CFU-S activity. This initial intrabody pattern of CFU-S distribution in murine embryogenesis parallels that found for primordial germ cells. (3) The beginning of definitive liver hematopoiesis is accompanied by wide dissemination of CFU-S in the embryonic tissues. (4) Comparison of spleen colonies arising from the AGM and YS has shown morphologic differences. In contrast to simple erythroid constitution of the YS colonies, a broader variety of cells are found within the AGM-derived colonies that are similar to those derived from 11-day FL. These data suggest a lineage relationship for hematopoietic progenitors between the AGM region and the FL.     

Lymphangioma of the kidney

Lymphangiomas are rare benign tumors that are congenital malformations of the lymphatic system. Most cases present in children as a soft, cystic mass in the neck and the axilla. Primary renal lymphangioma is exceedingly rare, with only 35 cases reported so far. We report a case of primary lymphangioma arising from the kidney. A 59-year-old man was referred for evaluation of a right renal mass found in an abdominal ultrasonography during a health checkup. Abdominal ultrasonography and computed tomography (CT) revealed a 3.2 x 2.9 cm multiloculated cystic mass in the upper pole of the right kidney. We could not deny malignant disease such as cystic renal cell carcinoma with any diagnostic modalities. The patient was brought to surgery. During the surgical procedure, the tumor was suspected to be lymphangioma of the kidney as a result of a frozen- section histopathological evaluation. Therefore enucleation of the tumor was performed. Pathological evaluation of the specimen revealed lymphangioma arising from the kidney. The patient is free of disease after a 3-month follow-up period.     

HIV感染者/AIDS患者血清基质金属蛋白酶-9表达与T细胞亚群的相关性研究

目的：了解艾滋病病毒(HIV)感染者及艾滋病(AIDS)患者血清中基质金属蛋白酶—9(MMP—9)水平表达及与T细胞亚群的相关性。方法：用酶联免疫吸附试验(ELISA)和流式细胞分析法，检测了18例HIV感染者和24例AIDS患者血清中MMP—9水平和淋巴细胞中CD3^ 、CD4^ 、CD9^ 的表达及绝对数。结果：HIV感染者组和AIDS患者组MMP—9水平较对照组明显升高(P＜0．05，P＜0.01)。AIDS患者组CD3^ 细胞数较对照组显著减少(P＜0．05)。HIV感染者组和AIDS患者组CD4^ 计数降低非常明显(P＜0．001)，CD8^ 计数非常明显升高(P＜0．00l，P＜0．01)，CD4^ ／CD8^ 的比值倒置。AIDS患者组MMP—9水平、CD3^ ，CD4^ 、CD8^ 的表达较HIV感染者组均有明显差异。HIV感染者组和AIDS患者组MMP—9表达与CD4^ 细胞数呈负相关(P＜0．05，P＜0．01)，AIDS患者组MMP—9水平与CD8^ 细胞数明显相关(P＜0．05)。结论:感染HIV后，MMP—9的水平随病情发展而增加，CD3^ 、CD4^ 细胞数逐渐减少，可作为判断AIDS患者疾病严重程度的指标。     

Listening to Chinese Immigrant Restaurant Workers in the Midwest: Application of the Culture-Centered Approach (CCA) to Explore Perceptions of Health and Health Care

This study engages with the culture-centered approach (CCA) to explore Chinese immigrant restaurant workers’ perception of the U.S. health care system and their interactions with the health care system in interpreting meanings of health. Chinese restaurant workers are marginalized because of their struggles on the job, their immigrant identity, and their negotiations with the structural contexts of occupation, migration status, and culture. In-depth interviews were conducted with 18 Chinese immigrant restaurant workers that lasted an average of 1.5 hours each, and were audiotaped. Interviews with participants highlighted critical issues in access to health care and the struggles experienced by restaurant workers in securing access to health, understood in the context of work. Critical to the workers’ discourse is the acknowledgment of structural constraints such as lack of insurance coverage, immigration status, and lack of understanding of how the U.S. health care system works.     

Family systems and HIV/AIDS in South Africa

This study examines the role of family in the care and support of people living with HIV/AIDS (PLWHA) as a way of reducing the burden of stigma in the family. The PEN-3 model provided the cultural framework for this study. Data were drawn from participants' responses in 27 focus groups interviews conducted in South Africa. Participants were asked to discuss experiences of people living with HIV and AIDS in the family. The results highlight the positive and supportive aspects of the family, acknowledge the existential and unique aspects, and discuss the negative experiences shared by participants. This study's findings stress the need to take into account families' experiences with HIV and AIDS in the development of interventions aimed at reducing the burden of the disease on family systems and improving care and support for PLWHA.     

Molecular evolutionary studies of Lassa virus nucleoprotein 2

ObjectiveTo study the virulence diversity through molecular evolution, and to provide insight on circulating antibodies.MethodsThe nucleotide sequences of 18 Lassa virus genomic RNA encoding Lassa virus nucleoprotein isolates collected from different parts of the world since the identification of the Josiah strain were obtained from the GenBank and nucleotide substitution among them studied using the computer program MEGA 4. The genetic distances among strains were predicted by pairwise nucleotide differences.ResultsThe rate of synonymous substitution was high 5.889 per nucleotide per year and nonsynonymous was higher at 49.664. The average predicted rate of synonymous and nonsynonymous using modified Nei-Gojobori (assuming transition/transversion bias=2) was 27.9 which was taken as the genetic distance between strains. The average number of synonymous sites is 150.741 while the average number of nonsynonymous sites is 392.259. The phylogenetic tree was inferred by unweighted pairwise grouping in MEGA4 and using neighbour-joining method. The time of emergence of Lassa virus was predicted to be around January 1920. However, the first human appearance of the virus was predicted to be around May (1 959±24) months. In synonymous substitution the rate of (G-T) rare was high. The nucleotide frequencies were 0.314 (A), 0.246 (T/U), 0.204 (C) and 0.235 (G). The transition/transversion ratio k₁=14.991 (purines) and k₂=69.916 (pyrimidines). The overall transition/transversion bias R=16.662 with a total of 620 position in the final data set. These figures are far higher than an earlier study using Lassa virus glycoprotein. The nucleotide diversity were also very high using the Taijima's model in MEGA 4.ConclusionsThe divergence within strains always coincides with the period of epidemic which goes to confirm that the cause of epidemic outbreak should be the emergence of new strain and also why the infection remains endemic despite circulating antibodies. A comparison with a similar study with the viral glycoprotein concludes that the glycoprotein is more suited for vaccine development.     

Hepatocellular carcinoma and the underlying mechanisms

The incidence of hepatocellular carcinoma is increasing worldwide as well as the associated risk factors, some of which include exposure to aflatoxin B1, Hepatitis B (HBV) virus and hepatitis C (HCV) virus. Mutation of tumour suppressor gene p53 at codon 249^ser at exon 7 has been found to contribute significantly to replication of damaged DNA and subsequent tumour progression. The x gene of HBV (HBx) is the most common open reading frame integrated into the host genome in hepatocellular carcinoma and the integrated HBx is frequently mutated in hepatocellular carcinoma. Mutant HBx proteins still retain their ability to bind to p53 thereby attenuating DNA repair and p53-mediated apoptosis.     

Refined mapping of genomic rearrangements involving the short arm of chromosome 9 in acute lymphoblastic leukemias and other hematologic malignancies

Deletions of chromosomal band 9p21 have been detected in various tumor types as well as in more than 20% of acute lymphoblastic leukemia (ALL). These deletions frequently include the entire interferon (IFN) gene cluster as well as the methylthioadenosine phosphorylase (MTAP) gene. Recently, the CDKN2 gene (p16INK4A, MTS I, CDK41) was proposed as a candidate tumor-suppressor gene on 9p21 because it is frequently deleted in cell lines derived from multiple tumor types. To determine if CDKN2 or another closely related gene on 9p is the target of 9p deletions in ALL and other hematologic malignancies, we analyzed 20 primary patient samples (13 ALL, 2 acute myeloid leukemias [AML], and 5 non-Hodgkin's lymphomas [NHL]) with 9p rearrangements using Southern blot analysis, fluorescence in situ hybridization (FISH), and single- strand conformation polymorphism (SSCP) for alterations of CDKN2. Homozygous deletions of the CDKN2/CDKN2B (p15) region were detected in 10 cases (50%; 6 ALL, 2 AML, and 2 NHL). In 1 additional case, the intensity of the Southern blot band was significantly reduced, suggesting a CDKN2 deletion in a subpopulation of the malignant cells. No CDKN2 or CDKN2B rearrangements were seen. The IFN gene cluster was homozygously deleted in 2 of 15 (13%) analyzed cases, whereas the MTAP gene was deleted in 6 of 15 cases (40%). In addition, hemizygous deletions of the CDKN2 region were identified in 6 ALL cases using interphase FISH. No point mutation of the coding region of CDKN2 was detected by SSCP in these cases. We conclude that CDKN2 is the most frequently homozygously deleted marker on 9p. The absence of point mutations in the coding region of CDKN2 in cases with hemizygous 9p deletions and the frequent codeletion of MTAP, CDKN2B, and other yet unidentified neighboring genes suggest that the simultaneous deletion of these genes may be necessary for the selective growth advantage of malignant cells.