Sry监测体外扩增造血细胞植入效果的实验研究

目的：探讨Y染色体性别决定基因(Sry)作为评价和追踪造血细胞移植后植入状态检测指标的可行性。方法：根据Sry DNA序列设计引物及制备探针，然后进行PCR检测、斑点杂交和原位杂交．动态追踪经不同条件下体外扩增的纯系雄性小鼠BMMNC回输至雌性小鼠后的植入状态。结果：PCR结果显示在各移植组小鼠的骨髓有核细胞、脾细胞及外周血白细胞中均有Y染色体特异性序列的存在；斑点杂交结果显示在各回输组间并无明显差别，但用脾脏组织作原位杂交的结果则发现基质细胞支持扩增回输组的阳性颗粒数目与输注新鲜细胞组相似，但略少于雄性小鼠；而输注细胞因子扩增细胞实验组小鼠则明显少于雄性动物的阳性对照标本和基质细胞支持扩增回输组。结论：(1)经重复检测表明上述方法的重复性好，结果可信．可作为检测性别不同时造血干细胞移植效果的一种检测手段；(2)证实基质细胞支持下的体外扩增的造血细胞具有较好的植入能力。     

The many ways to mend your liver: A critical appraisal

In the latter half of the 20th century, our understanding of mammalian liver regeneration was shaped by the manner of compensatory hyperplasia occurring after a partial rat liver resection. This response involves almost all hepatocytes and thus is unlikely to be the outcome of the multiple cycling of a small stem cell population. It was most intense in the outer third of lobule, the location closest to the afferent arterial blood supply. With the advent of heritable genetic labelling techniques, usually applied to mice, hitherto unrecognized hepatocytes with clonogenic potential have been discovered, contributing to homoeostatic renewal and/or regenerative responses after tissue loss. This review combines observations from cell lineage tracing studies with other data to summarize the Four proposed anatomical locations for hepatocyte stem cells: the periportal zone, the pericentral zone, a randomized distribution and finally within the intrahepatic biliary tree. As in other endodermal‐derived tissues, it appears that there are both homoeostatic stem cells and regenerative stem cells, while some normally homoeostatic stem cells can become more active to boost regeneration.     

Detection of the proliferated donor cells in bone grafts in rats, using a PCR for a Y-chromosome-specific gene

Conventional corticocancellous bone grafts are known to revascularize gradually and to become repopulated with osteocytes and other types of cells. This study was conducted to study the origin of the cells found within conventional bone grafts as a function of time, using a new method which accurately identifies donor cells transplanted with the graft. The technique requires the transplantation of a 25-mm tibial diaphyseal bone graft from a male rat to a female isogenous recipient, placed anatomically in the tibia. The presence and relative proportion of cells containing the Y-chromosome (i.e., originating from the bone graft) was determined 4, 8, and 12 weeks after transplantation. At these times, genomic DNA was extracted from the grafted bones and a polymerase chain reaction (PCR) specific for the sex-determining region of the Y-chromosome (Sry) was performed, with appropriate controls. Sry-specific bands were evident in none out of three grafts at 4 weeks, two out of three at 8 weeks, and all grafts at 12 weeks. These data demonstrate that not all cells within a conventional graft result from "creeping substitution" of necrotic bone. Instead, a small number of intrinsic cells from a nonvascularized corticocancellous structural graft survive and proliferate over time. Received: June 19, 2001 / Accepted: October 30, 2001     

Cell traffic between donor and recipient following rat limb allograft.

Although cell traffic from the graft into the recipient and from the recipient into the graft had been noticed in allogeneic organ transplantation, little is known following whole-limb allografting. This study was conducted to define cell migration between donor and recipient. Sixty-seven vascularized hind limb allotransplantations were performed in rat sex-mismatched pairs and the recipient animals were treated with FK506 immunosuppression. The ratio of donor and recipient cells was evaluated by semi-quantitative PCR using the specific primers of the Y-chromosome. Allografted limbs had no rejection episode until the final assessment. The male recipient cells were detected in female limb grafts not at 1 week but at 48 weeks after transplantation. The male donor cells were detected in the humerus and tibia in the female recipient but not in the gastrocnemius muscle and leg skin. Our results demonstrated that recipient-derived cells gradually migrated into the grafted bone, muscle and skin cells with the duration of time. Donor-derived cells migrated into the healthy bones but not into the healthy muscle and skin. Because active regeneration occurs in the grafted limb to compensate graft damage secondary to ischemia and operative intervention, recipient-derived cells may mediate a muscular and dermo-epidermal renewal.     

Genetic and Environmental Influences on 2D:4D Finger Length Ratios: A Study of Monozygotic and Dizygotic Male and Female Twins

Recent studies have shown significant sex differences in the pattern of 2D:4D finger length ratios in humans and several other mammalian species. In humans, these ratios are suggested to be negatively correlated with prenatal exposure to testosterone, positively correlated with prenatal estrogen, and exhibit sex specific patterns of association with sexually dimorphic clinical phenotypes. However, the relative contributions of genetic and environmental influences on digit ratios in men and women are currently unknown. Therefore, the purpose of the current study was to examine genetic and environmental influences on 2D:4D ratios in twins. Participants included 146 monozygotic (MZ) and 154 dizygotic (DZ) adult male and female twins participating in the Michigan State University Twin Study of Behavioral Adjustment and Development. Overall, biometric model-fitting analyses indicated significant additive genetic and nonshared environmental influences on digit ratios. Findings suggest greater similarity between 2D:4D ratios in MZ relative to DZ twins that can be accounted for by genetic and nonshared environmental factors.     

Sex differences in Attention Deficit Hyperactivity Disorder: Candidate genetic and endocrine mechanisms

Attention Deficit Hyperactivity Disorder (ADHD) is a developmental condition characterised by severe inattention, pathological impulsivity and hyperactivity; it is relatively common affecting up to 6% of children, and is associated with a risk of long-term adverse educational and social consequences. Males are considerably more likely to be diagnosed with ADHD than females; the course of the disorder and its associated co-morbidities also appear to be sensitive to sex. Here, I discuss fundamental biological (genetic and endocrine) mechanisms that have been shown to, or could theoretically, contribute towards these sexually dimorphic phenomena. Greater understanding of how and why the sexes differ with respect to ADHD vulnerability should allow us to identify and characterise novel protective and risk factors for the disorder, and should ultimately facilitate improved diagnosis, prognosis and treatment.