Rag-1: a topoisomerase?

Recombination activating genes Rag-1 and Rag-2 were isolatedon the basis of their ability to confer V(D)J recombinationactivity when co-expressed in fibroblasts. The mode of actionof the products of these genes is not known. Based on sequencecomparison data, it was suggested that Rag-1 protein could actlike a topoisomerase and that tyroslne in position 998 couldbe the active site tyrosine. We tested this hypothesis by introducinga point mutation on the Rag-1 cDNA, transforming the tyrosinecodon into a phenylalanine codon. We show that the mutationhas no effect on site specific recombination implying that Tyr-998is not essential for the recombination reaction.     

Type 1 1/2 diabetes: myth or reality?

The disease process in classical Type 1 diabetes patients (IDDM) is believed to be autoimmune. In contrast, the disease process in classical Type 2 diabetes patients (NIDDM) is not autoimmune and a decreased sensitivity to insulin action is the main abnormality. The clinical distinction of Type 1 diabetes versus Type 2 diabetes is recognized to be imperfect and has limitations. There is a group of individuals (Type 1 1/2 diabetes), who present like typical NIDDM, but have some of the immunological and clinical features of IDDM. We review the current medical literature on Type 1 1/2 diabetes with special reference to its clinical characteristics, natural history and pathophysiology. Since the distinction between these two forms of diabetes may have important therapeutic implications especially with regards to the benefits of insulin therapy in patients with Type 1 1/2 diabetes and because of the need for uniformity in its diagnosis we recommend that both clinical plus biochemical criteria (the presence of ICA and/or GAD Ab, HLA typing and tests to quantify beta cell function) be used to make a diagnosis. Comparative studies in the area of cytokine production, T cell reactivity and autoantibody clustering between classic Type 1 diabetes and Type 1 1/2 diabetes patients are needed as are studies with the animal model of Type 1 1/2 diabetes, Psammomys obesus.     

平衡易位t(1:4)伴流产1例

病例 患者,女,24岁,婚后怀孕2次,第1次孕4个月,B超检查:发现胎儿发育不良约2个半月大小而行流产术.第2次孕3个月不明原因流产.夫妇表型、智力正常,非近亲结婚,无接触有害物质.     

手指末节再植动静脉1:1吻合100例

我院自1999年以来至今，对100例手指末节完全离断伤进行动静脉1：1吻合再植后均完全成活。现将手术体会及要点报道如下。     

HLA-DRB1*12:01:01G和HLA-DRB1*14:01:01G组内等位基因频率的统计分析

目的 区分并计算人类白细胞抗原(human leukocyte antigen,HLA) HLA-DRB1* 12:01:01G(HLA-DRB1* 12:01:01/12:06/12:10/12:17)和HLA-DRB1* 14:01:01G(DRB1* 14:01:01/14:54)组内等位基因及其相对频率,并分析其与HLA-DRB3和HLA-DQB1的连锁情况.方法 收集115例HLA-DRB1*12:01:01G组和108例HLA-DRB1*14:01:01G组标本,采用单核苷酸序列分析(polymerase chain reaction-sequence based typing,PCR-SBT)方法检测HLA-DRB1* 12:01:01G组等位基因的第1～3外显子序列和HLA-DRB1* 14:01:01G组的第2、3外显子序列.HLA-DRB3和HLA-DQB1基因分型采用PCR-SBT方法.结果 115例HLA-DRB1* 12:01:01G组标本中,101例(87.8％)为HLA-DRB1* 12:01:01,14例(12.2％)为HLA-DRB1* 12:10,未发现HLA-DRB1* 12:06和HLA-DRB1* 12:17. 108例HLA-DRB1*14:01:01G组标本全部为HLA-DRB1*14:54. HLA-DRB1*12:01:01与HLA-DRB3* 01:01:02和HLA-DQB1* 03:01连锁,HLA-DRB1* 12:10则与HLA-DRB3* 02:02:01和HLA-DQB1* 03:01连锁.HLA-DRB1* 14:54与HLA-DRB3* 02:02:01和HLA-DQB1* 05:02、*05:03连锁.结论 HLA-DRB1* 12:01:01G组中HLA-DRB1* 12:01:01频率最高,而HLA-DRB1* 14:01:01G组则以HLA-DRB1* 14:54频率最高.     

Rapid rescreen: a viable alternative to 1:10?

A rapid screen of those Pap smears designated as within normal limits is a quality control requirement of all UK laboratories. However in the United States standard QC involves a combination of 1:10 and selective rescreening procedures. Forty participants at the joint ASCT/ACP meeting in Las Vegas rapid screened 50 slides as part of a rapid screening workshop. They used different patterns of screening but were allowed only 60 seconds for each slide. Thirty of the slides contained abnormal cells but all had originally been called negative or unsatisfactory and as such were "false negatives". Ability to identify the abnormal smears varied considerably between individuals but overall rapid screening correctly identified 54% of the ascus or LGSIL cases and 61% of the HGSIL cases. The results demonstrate the superiority of such a rapid screen over 1:10 and question what if any role this outdated practice should have.     

MAdCAM-1分子:免疫生物学功能

有关MAdCAM 1分子生物学功能的研究目前虽属初级阶段 ,但至少已知它与淋巴归巢、肠道相关淋巴组织的发育、淋巴细胞活化及炎症反应等多种生理和病理过程有关。本文拟就其上述功能作一讨论。     

CD1:第三类抗原递呈分子

CD1分子是不同于MHCⅠ类和Ⅱ类分子的第三类抗原递呈分子,它能将脂类抗原递呈给某些亚群的T细胞,这些受CD1分子限制的T细胞虽然数量不多,但却在T细胞发育、免疫调节、粘膜免疫以及自身免疫等过程中具有重要作用。     

B-1 cells: orthodox or conformist?

B-1 cells differ from conventional peripheral B cells (B-2) by anatomical location, surface marker expression, antibody repertoire and growth properties. The lineage hypothesis of B-1 cell development attributes the properties of B-1 cells to their unique origin. The induced differentiation hypothesis suggests the surface-immunoglobulin-driven development of B-1 cells from common B-1/B-2 cell progenitors. In both models self-antigen-induced signalling plays the central role in positive selection of B-1 cells. The ability of B-1 cells to be positively selected by self-antigens raises questions about the mechanism of this phenomenon.     

006 MAdCAM-1分子:免疫生物学功能

有关MAdCAM-1分子生物学功能的研究目前虽属初级阶段,但至少已知它与淋巴归巢、肠道相关淋巴组织的发育、淋巴细胞活化及炎症反应等多种生理和病理过程有关.本文拟就其上述功能作一讨论.     

SMARCB1/INI1与儿童脊索瘤:基因突变及免疫组化分析

<正>脊索瘤好发于颅底和脊柱的浸润性骨肿瘤,起源于残留的胚胎脊索。通常发生在成人,儿童罕见,20岁以下的患者5%。组织学显示儿童脊索瘤常为低分化,出现细胞异型性、细胞数量增加、核分裂常见,具有侵袭性、转移扩散率高、生存率低等特点。目前分析认为低分化的脊索瘤与SMARCB1/INI1基因缺失有关。为更清楚了解SMARCB1/