Lifelong hematopoiesis in both reconstituted and sublethally irradiated mice is provided by multiple sequentially recruited stem cells

OBJECTIVE: To evaluate the dynamics of stem cell production to hematopoiesis, the number of active stem cell clones and the lifespan of individual clones were studied. MATERIALS AND METHODS: The clonal contribution of primitive hematopoietic stem cells (HSC) responsible for long-term hematopoiesis was determined using two approaches. In one model, irradiated female mice were reconstituted with retrovirally marked male hematopoietic cells. In the second model, mice were irradiated sublethally without hematopoietic cell transplantation. In both models, bone marrow cells were serially sampled from the same mouse throughout a 12- to 20-month period and injected into irradiated recipients for analysis of day 10 colony-forming unit-spleen (CFU-S). The donor origin of CFU-S was determined by the presence of retrovirally marked cells or cells with chromosomal aberrations. RESULTS: The results of the two essentially different models show that 1) hematopoiesis is mainly the product of small clones of hematopoietic cells; 2) the lifespan of the majority of clones is only 1 to 2 months; 3) the clones usually function locally; and 4) the vast majority of the clones replace one another sequentially. Primitive HSCs capable of producing long-lived clones (about 10% among all clones), which exist during the entire life of a mouse, were detected by the radiation-marker technique only. CONCLUSION: Multiple short-living clones (at least on the level of CFU-S production) comprise the vast majority of the active stem cells in transplanted recipients or after endogenous recovery from sublethal irradiation.     

肿瘤相关基因Cap43在胰腺癌中的表达及意义

目的研究肿瘤相关基因Cap43在胰腺癌组织中的表达情况,探讨其对胰腺癌的诊断价值。方法收集1999年4月～2002年8月长海医院外科手术切除胰腺癌标本和癌旁正常组织33例,诊断均由病理证实。男性22例,女性11例,年龄30～73岁,平均58．1岁。所有组织标本按肿瘤、癌旁(正常)配对。采用RT-PCR和Northern杂交方法研究Cap43 mRNA表达情况。结果 RT-PCR结果显示,Cap43在肿瘤组织中表达显著上调,其在肿瘤组织和癌旁正常组织的扫描值分别为4 033±1 986和2 244±1 145,有显著差异(P<0．001)。Northern杂交亦显示Cap43在肿瘤组织中表达显著上调,相同病例的RT-PCR结果与Northern杂交的结果有较好的一致性,经回归分析,没有显著性差异(P>0．1)。结论 Cap43在胰腺癌组织中呈显著高表达,其有可能成为胰腺癌早期诊断的重要标志物。     

Laparoscopic Right Hemicolectomy for Ileocolic Intussusception Secondary to Caecal Neoplasm

Intussusception in adults is a rare cause of abdominal pain. Unlike its paediatric counterpart, intussusception in adults is associated with obvious pathology. We describe a case of ileocolic intussusception extending to the splenic flexure. We were able to reduce the intussusception partially and pedicle was stapled carefully. The specimen was delivered through a small incision and right hemicolectomy was performed adhering to oncological principles. We recommend laparoscopic-assisted surgery is considered for adult intussusceptions.     

Long-term experience with implanted intrathecal drug administration systems for failed back syndrome and chronic mechanical low back pain

Background  

Continuous intrathecal drug delivery has been shown in open studies to improve pain and quality of life in those with intractable back pain who have had spinal surgery. There is limited data on long term effects and and even less for patients with mechanical back pain without prior spinal surgery.     

PAQR3: a novel tumor suppressor gene

PAQR3, also known as RKTG (Raf kinase trapping to Golgi), is a member of the progestin and adipoQ receptor (PAQR) family. The role of PAQR3 as a tumor suppressor has recently been established in different types of human cancer in which PAQR3 exerts its biological function through negative regulation of the oncogenic Raf/MEK/ERK signaling. Multiple studies have found that PAQR3 downregulation frequently occurs in human cancers and is very often associated with tumor progression and shortened patients’ survival. Moreover, restoring the expression of PAQR3 could induce apoptosis and inhibit proliferation and invasiveness of cancer cells. Downregulation of PAQR3 by oncogenic microRNAs has also been reported. In this review, we summarized current knowledge concerning the role of PAQR3 in tumor development. To our knowledge, this is the first review on the role of this novel tumor suppressor.