免疫抑制酸性蛋白单克隆抗体MI-2体外抗肿瘤作用的观察

作者采用MTT比色法观察了本室自制免疫抑制酸性蛋白单克隆抗体MI-2的体外抗肿瘤作用。结果表明:MI-2在浓度为7.81 μg/ml时即可明显抑制胃癌细胞株SGC 7901的生长(抑制率7.5％±2.4％,P<0.01),并见剂量依赖型表现;在LAK细胞与SGC 7901胃癌细胞的效靶比为10:1时,加入1.95 μg/ml的MI-2即可明显增强LAK细胞的细胞毒作用(增强效应为206.3％,P<0.01),也呈剂量依赖性表现。作者还发现MI-2的这种抗肿瘤作用与补体无关。     

Developmental derivation of embryonic and adult macrophages

The macrophage cell lineage continually arises from hematopoietic stem cells during embryonic, fetal, and adult life. Previous theories proposed that macrophages are the recent progeny of bone marrow-derived monocytes and that they function primarily in phagocytosis. More recently, however, observations have shown that the ontogeny of macrophages in early mouse and human embryos is different from that occurring during adult development, and that the embryonic macrophages do not follow the monocyte pathway. Fetal macrophages are thought to differentiate from yolk sac-derived primitive macrophages before the development of adult monocytes. Further support for a separate lineage of fetal macrophages has come from studies of several species, including chicken, zebrafish, Xenopus, Drosophila, and C. elegans. The presence of fetal macrophages in PU.1-null mice indicates their independence from monocyte precursors and their existence as an alternative macrophage lineage.     

Cell‐free fetal DNA in the maternal circulation originates from the cytotrophoblast: proof from an unique case

Noninvasive prenatal testing (NIPT) and direct karyotyping of cytotrophoblast were normal for a male fetus, but cultured chorionic villus mesenchymal cells and umbilical cord fibroblasts showed nonmosaic trisomy 18. This observation provides direct evidence for the cytotrophoblastic origin of cell‐free fetal DNA and yields a biological explanation for falsely reassuring NIPT results.     

Myelopoiesis in the zebrafish, Danio rerio

Genome-wide chemical mutagenesis screens in the zebrafish (Danio rerio) have led to the identification of novel genes affecting vertebrate erythropoiesis. In determining if this approach could also be used to clarify the molecular genetics of myelopoiesis, it was found that the developmental hierarchy of myeloid precursors in the zebrafish kidney is similar to that in human bone marrow. Zebrafish neutrophils resembled human neutrophils, possessing segmented nuclei and myeloperoxidase-positive cytoplasmic granules. The zebrafish homologue of the human myeloperoxidase (MPO) gene, which is specific to cells of the neutrophil lineage, was cloned and used to synthesize antisense RNA probes for in situ hybridization analyses of zebrafish embryos. Granulocytic cells expressing zebrafish mpo were first evident at 18 hours after fertilization (hpf) in the posterior intermediate cell mass (ICM) and on the anterior yolk sac by 20 hpf. By 24 hpf, mpo-expressing cells were observed along the ICM and within the developing vascular system. Thus, the mpo gene should provide a useful molecular probe for identifying zebrafish mutants with defects in granulopoiesis. The expression of zebrafish homologues was also examined in 2 other mammalian hematopoietic genes, Pu.1, which appears to initiate a commitment step in normal mammalian myeloid development, and L-Plastin, a gene expressed by human monocytes and macrophages. The results demonstrate a high level of conservation of the spatio-temporal expression patterns of these genes between zebrafish and mammals. The morphologic and molecular genetic evidence presented here supports the zebrafish as an informative model system for the study of normal and aberrant human myelopoiesis. (Blood. 2001;98:643-651)     

Diverting ileostomy in laparoscopic rectal cancer surgery: high price of protection

Background

Anastomotic leakage presents the most feared complication after low anterior resection (LAR). A proximal diversion of the gastrointestinal tract is recommended to avoid septic complications of anastomotic leakage. The aim of the present study was to evaluate the benefits and risks of diverting ileostomy (DI) created during laparoscopic LAR because of low rectal cancer.

Methods

This was a retrospective clinical cohort study conducted to assess outcomes of laparoscopic LAR with/without DI in a single institution within a 6-year period.

Results

In total, 151 patients were enrolled in the study (73 patients without DI, 78 patients with DI). There were no significant differences between both groups regarding demographic and clinical features. Overall 30-day morbidity rates were significantly lower in patients without DI (23.3 vs. 42.3 %, P = 0.013). Symptomatic anastomotic leakage occurred more frequently in patients without DI (9.6 vs. 2.5 %, P = 0.090); surgical intervention was needed in 6.8 % of patients without DI. Post-operative hospital stay was significantly longer in the group of patients with DI (11.3 ± 8.5 vs. 8.1 ± 6.9 days, P = 0.013). Stoma-related complications occurred in 42 of 78 (53.8 %) patients with DI; some patients had more than one complication. Acute surgery was needed in 9 patients (11.5 %) because of DI-related complications. Small bowel obstruction due to DI semi-rotation around its longitudinal axis was seen in 3 patients (3.8 %) and presents a distinct complication of DI laparoscopic construction. The mean interval between LAR and DI reversal was more than 8 months; only 19.2 % of patients were reversed without delay (≤4 months). Morbidity after DI reversal was 16.6 %; re-laparotomy was necessary in 2.5 % of patients.

Conclusions

The present study indicates that DI protects low rectal anastomosis from septic complications at a cost of many stoma-related complications, substantial risk of acute surgery necessity and long stoma periods coupled with decreased quality of life.

     

Hematopoiesis and stem cells: plasticity versus developmental heterogeneity

Hematopoietic stem cells (HSCs) provide for blood formation throughout the life of the individual. Studies of HSCs form a conceptual framework for the analysis of stem cells of other organ systems. We review here the origin of HSCs during embryological development, the relationship between hematopoiesis and vascular development and the potential plasticity of HSCs and other tissue stem cells. Recent experiments in the mouse have been widely interpreted as evidence for unprecedented transdifferentiation of tissue stem cells. The use of enriched, but impure, cell populations allows for alternative interpretation. In considering these findings, we draw a distinction here between the plasticity of adult stem cells and the heterogeneity of stem cell types that pre-exist within tissues.