Difference in cell binding patterns of two monoclonal antibodies recognizing distinct epitopes on a human melanoma-associated oncofetal antigen

Two monoclonal antibodies (MAbs), 140.240 and 96.5, generated independently in different laboratories, have been shown to detect the target structures of 87,000 (gp87) and 97,000 (p97) glycoproteins, respectively, both strongly expressed by melanoma cells and fetal small intestine. To determine whether MAb 140.240 and MAb 696.5 recognized a same target structure, they were tested in immunoprecipitation/SDS-PAGE using NP-40 lysates of melanoma cells labelled with [35S]methionine for 18 hr. Both antibodies precipitated a single band with Mr = 87,000. Reciprocal immunodepletion studies showed that neither of the two antibodies detected the 87,000 band in the lysate immuno depleted by either antibody, suggesting that these two antibodies recognize the same or extremely similar molecules. Two-dimensional tryptic peptide mapping analysis showed that the two identified molecules shared the same finger-printing pattern. A 40,000 fragment of the 87,000 molecule produced by protease digestion was precipitated by MAb 96.5 but not MAb 140.240, indicating that the epitopes recognized by the two antibodies are localized at discrete sites on the molecule. Serological studies on these two antibodies revealed slightly different binding patterns in the MAb 140.240 exhibited a more melanoma-restricted specificity, while MAb 96.5 had a specificity to melanoma and to some other cell types. The observed difference in epitope specificity may be important in the clinical applications of these antibodies.     

Expression of the CD7 Ligand K-12 in Human Thymic Epithelial Cells: Regulation by IFN-γ

CD7 is an immunoglobulin superfamily molecule expressed on T, NK, and pre-B lymphocytes. Previous studies have demonstrated a role for CD7 in T- and NK-cell activation and cytokine production. Recently, an epithelial cell secreted protein, K12, was identified as a CD7 ligand. Although CD7 is expressed intrathymically, it is not known if K12 is produced in human thymus. To determine roles that K12 might play in the human thymus, we analyzed expression of K12 in human thymocytes, thymic epithelial cells (TE), and thymic fibroblasts. We found that recombinant human K12 bound strongly to soluble hCD7, with a K_eq of 37.6×10^–9M, and this interaction was inhibited by a novel antihuman K12 monoclonal antibody (K12-A1). K12 mRNA was detected by RT–PCR and northern analysis in human TE and thymic fibroblasts, but not in human thymocytes. Expression of K12 in TE cells was upregulated by IFN- . Taken together, these data demonstrated that K12 is produced by human TE cells and thymic fibroblasts, and is regulated in thymus by IFN- . These data suggest a role for thymic microenvironment-produced K12 in regulation of thymocyte signaling and cytokine release, particularly in the setting of thymus pathology where IFN- is upregulated such as myasthenia gravis.     

Identification of neural genes using Xenopus DNA microarrays.

To isolate novel genes regulating neural induction, we used a DNA microarray approach. As neural induction is thought to occur by means of the inhibition of bone morphogenetic protein (BMP) signaling, BMP signaling was inhibited in ectodermal cells by overexpression of a dominant-negative receptor. RNAs were isolated from control animal cap explants and from dominant-negative BMP receptor expressing animal caps and subjected to a microarray experiment using newly generated high-density Xenopus DNA microarray chips representing over 17,000 unigenes. We have identified 77 genes that are induced in animal caps after inhibition of BMP signaling, and all of these genes were subjected to whole-mount in situ hybridization analysis. Thirty-two genes showed specific expression in neural tissues. Of the 32, 14 genes have never been linked to neural induction. Two genes that are highly induced by BMP inhibition are inhibitors of Wnt signaling, suggesting that a key step in neural induction is to produce Wnt antagonists to promote anterior neural plate development. Our current analysis also proves that a microarray approach is useful in identifying novel candidate factors involved in neural induction and patterning.     

大鼠睾丸血管构筑的观察

本文通过血管灌注透明标本和微血管腐蚀铸型扫描电镜,观察大鼠睾丸的大血管和微细血管的构筑。大鼠生精小管的周围,有两种小血管配布。1.管间血管:该血管或为1条毛细血管前微动脉,或为2条并行的较大的毛细血管连结成网状,位于生精小管间三角形的间质柱内,并与小管平行走行。2.管周毛细血管:连于管间血管之间,呈绳梯状围绕生精小管,并在生精小管上皮下固有膜内,形成管周毛细血管网。本文还观察了大鼠睾丸较大血管及睾丸固有鞘膜脏层的血管配布特点,讨论了这些血管配布的意义。     

Leu-676-Pro mutation of the androgen receptor causes complete androgen insensitivity syndrome in a large Hutterite kindred

A large Manitoba Hutterite kindred with X-linked receptor negative complete androgen insensitivity syndrome (CAIS) was studied. In attempts to identify all carriers of the syndrome in this kindred, using the androgen receptor (AR) cDNA, we have found a novel diagnostic Mspl polymorphic pattern, which cosegregates with the disease. This polymorphism was not detected in 79 unrelated X-chromosomes of which 22 were from Hutterite controls. We were able to localize the polymorphism to exon 4, which is known to encode part of the androgen receptor hormone binding domain. A single base substitution (T→C) was detected, which creates a new Mspl site. This novel transition mutation replaces Leu-676 with Pro at a site which is conserved in numerous members of the steroid receptor gene family. Sequencing all 8 exons of the AR revealed the Leu-676→Pro mutation as the only change in the primary structure of the receptor. Transfection of COS-l cells with an expression vector of the mutant AR demonstrates that this point mutation of nucleotide 2558 abolishes receptor binding activity. The mutation can easily be detected by MspI digestion of the polymerase chain reaction (PCR) amplified exon 4 product.© 1995 wiley-Liss, Inc.     

细胞周期蛋白E对乳腺癌细胞MCF-7生长及周期相关基因的影响

观察细胞周期蛋白（ｃｙｃｌｉｎ）Ｅ的表达对乳腺癌细胞ＭＣＦ－７生长及其他周期相关基因的影响。方法构建正义和反义ｃｙｃｌｉｎ Ｅ ｃＤＮＡ真核表达载体,并采用ｌｉｐｏｆｅｃｔ ＡＭＩＮＥ转染,将其导入ＭＣＦ－７细胞,获得稳定表达正义及反义ｃｙｃｌｉｎＥ的细胞系,经Ｓｏｕｔｈｅｒｎ和Ｗｅｓｔｅｒｎ ｂｌｏｔ检测有外源性片片段的插入及表达,并作细胞生长曲线、四甲偶氮唑盐（ＭＴＴ）法和流式细胞计数分析;用     

Community-acquired anaerobic bacteremia in adults: one-year experience in a medical center.

A prospective observational study was conducted to evaluate the clinical characteristics and outcome of community-acquired anaerobic bacteremia. From June 1 2001 through May 31 2002, 52 patients with community-acquired anaerobic bacteremia were enrolled at the emergency department in a teaching hospital. There were 19 patients (34%) with polymicrobial bacteremia and Escherichia coli was the most common copathogen (n = 6). Of 62 anaerobic isolates, species of the Bacteroides fragilis group were the most common isolates (n = 28, 45%), followed by Clostridium spp. (n = 11, 18%). Among the 52 patients enrolled, up to 27% had underlying malignancy and the gastrointestinal tract accounted for 48% of the sources of infection. Clinical manifestations suggesting anaerobic infections were common and three-quarters (n = 39) of 52 patients received adequate empirical antimicrobial treatment. Documentation of anaerobic bacteremia seldom influenced antimicrobial treatment. The 30-day mortality was 25%. Although univariate analysis revealed that underlying malignancy (p=0.003), leukopenia (p=0.044) and absence of fever (p=0.047) were associated with mortality, only malignancy (p=0.007) was an independent risk factor in the multivariate analysis.     

An innovative, longitudinal program to teach residents about end-of-life care.

At the University of California, Irvine Medical Center, an end-of-life curriculum was implemented in 2000 for an internal medicine residency utilizing a longitudinal approach that allowed residents to follow patients through their entire hospice experience. An elective home hospice rotation was developed for which third-year residents served as primary care physicians for patients at the end of life over a one-year period. Residents were supervised by faculty who were hospice medical directors. They also learned through case vignettes, quarterly meetings, textbook reading, and personal projects. From July 2000 to June 2002, residents demonstrated positive attitudes towards hospice care and recommended the rotation highly (mean 8.86 on a scale of 1-10). The rotation grew in popularity from six initial residents to ten residents the next year, and has since become a mandatory rotation for all senior residents. A 360-degree evaluation uniformly indicated positive resident performance from the hospice team (mean scores 7.56-8.69 on a 1-9 scale), family (mean scores 9.3-9.7 on a 1-10 scale) and faculty (mean scores 7.29-7.72 on a 1-9 scale). Residents were also pleased with the level of teaching (mean 8.86 on a scale of 1-10) and felt that the patient care load was "just right." Their knowledge improved by 8% (p =.0175). In conclusion, a longitudinal hospice rotation was implemented that fulfilled curricular goals without undue burden on the residents or residency program.     

端粒酶转录酶及其调节相关蛋白与增殖细胞核抗原在卵巢上皮性肿瘤中的表达及临床意义

目的　探讨端粒酶转录酶 (hTERT)及端粒酶调节相关蛋白 (TRAP)与增殖细胞核抗原(PCNA)在卵巢上皮性肿瘤中的表达和临床意义。方法　收集 10 6例卵巢上皮性肿瘤 (恶性 5 4例 ,交界性 33例 ,良性 19例 )的临床资料 ,行hTERT、TRAP和PCNA 3种抗体的免疫组织化学标记链霉素卵白素生物素 (LSAB)法染色。对 87例恶性和交界性患者进行了随访 ,4 5例获结果 ,随访时间为 2～6 0个月。结果　hTERT蛋白的表达在良性 (4/ 19)和交界性 (90 9% ,30 / 33)以及良性和恶性(94 4 % ,5 1/ 5 4 )间的差异均有显著性 (P均 <0 0 0 1) ,TRAP蛋白的表达在良性 (4/ 15 )和恶性(77 8% ,2 8/ 36 )间的差异有显著性 (P <0 0 0 1) ;hTERT和TRAP蛋白的表达在卵巢癌Ⅰ、Ⅱ期和Ⅲ、Ⅳ期两组病例中的差异均无显著性 (P >0 0 5 ,P >0 3)。PCNA的表达在良性 (6 9± 5 9) %和交界性 (2 6 4± 17 8) %、良性和恶性 (5 1 8± 2 2 1) %以及交界性和恶性间的差异均有显著性 (P <0 0 1,P <0 0 0 1,P <0 0 5 )。 33例交界性患者全部存活 ,5 4例恶性患者中 35例 (6 4 8% )有转移 (包括 5例淋巴结转移 ) ,4例 (7 4 % )死亡。结论　hTERT和TRAP蛋白的表达与卵巢上皮性肿瘤的良恶性有关 ,但与其临床分期无关 ;hTERT和TRAP蛋白的表达相似     

Hypoxia can contribute to the induction of the Epstein-Barr virus (EBV) lytic cycle.

BACKGROUND: Like other herpes viruses, latent Epstein-Barr virus (EBV) infection can be reactivated to lytic replication. Reactivation can be achieved by treatment with various reagents, including tetradecanoyl phorbol acetate (TPA) and Ca2+ ionophores. Relatively little is known about the physiological factors related to reactivation of EBV. Previous studies have demonstrated that G0/G1 cell cycle arrest is associated with EBV activation, and that hypoxic conditions can induce cell cycle arrest. In the present study we investigated the effect of hypoxia on reactivation of EBV. OBJECTIVE AND METHODS: Hypoxic culture conditions were established and the expression of Zta protein and the number of EBV DNA copies were measured in B95-8 cells maintained under these conditions. RESULTS: Hypoxia treatment not only increased the expression of the EBV immediate-early protein Zta (which mediates the switch between the latent and lytic form of infection), but also increased the number of EBV DNA copies in B95-8 cells. CONCLUSIONS: EBV in latent infection can be activated to lytic infection by hypoxia treatment.