瘢痕疙瘩家系Fas基因的突变：2个家系10份标本分析

目的:观察瘢痕疙瘩家系样本中Fas基因有无突变,探讨Fas基因突变在瘢痕疙瘩形成中的意义。方法:实验于2005-01/05在上海基康公司完成。①标本来自南方医科大学南方医院整形外科2005年收集的A和B两个瘢痕疙瘩家系,所有参与观察的家系成员均签署知情同意书。②采用聚合酶链反应及基因测序技术,分别以A家系两例患者的瘢痕疙瘩组织为观察对象,以其周围正常皮肤及外周静脉血作为自身对照;其配偶的外周静脉血作为正常对照。并以B家系中两例患者的外周静脉血作为不同家系间的对照。共取10份样本,4份组织样本,6份静脉血标本。检测10份样本中Fas基因外显子1～9的基因序列。结果:①基因测序发现所检测的10个瘢痕疙瘩家系标本Fas基因的1～8外显子均未发现突变。②2份瘢痕疙瘩组织标本在第9外显子编码区的11bp,53bp两个位点上存在单个碱基的基因突变或多态性改变。结论:瘢痕疙瘩Fas基因外显子9区段的基因结构异常极有可能造成Fas蛋白的功能改变,从而导致身体局部瘢痕疙瘩的形成。     

H-2-restricted cytotoxic effectors generated in vitro by the addition of trinitrophenyl-conjugated soluble proteins

Murine spleen cells from normal donors were cultured in vitro with trinitrobenzene sulfonate (TNBS)-conjugated soluble proteins, i.e., bovine gamma globulin (TNP-BGG) or bovine serum albumin (TNP-BSA). Addition of 100 μg of any of these TNP-proteins to the spleen cell cultures led to the generation of cytotoxic T-cell effectors which were H-2-restricted and TNP- specific. The lytic potential of such effectors was comparable to that generated by sensitization with TNBS-modified syngeneic cells, and was restricted to haplotypes shared at the K or K plus I-A, or the D regions of the H-2 complex. Greater effecter cell activity was generated by addition of TNP-BGG against TNBS-modified targets which shared K plus I-A than against modified targets which shared the D region with the responding cells, which suggests that the same immune response genes are involved when the response is generated by the addition of TNP-conjugated soluble proteins or of TNBS- modified cells. H-2-restricted, TNP-specific effecter cells were generated by culturing mouse spleen cells with syngeneic cells which had been preincubated with TNP- BGG or TNP-BSA for 1.5 h. The addition of unconjugated soluble proteins to the cultures did not result in cytotoxic effectors detectable on H-2-matched targets, whether the targets were prepared by modification with TNBS, or by incubation with either the unconjugated or TNP-conjugated proteins. Depletion of phagocytic cells in the tumor preparation by Sephadex G-10 column fractionation before incubation with TNP-BSA had no effect on their lysis by the relevant effector cells. Immunofluorescent staining of tumor target cells with anti-TNP antibodies indicated that TNP could be detected on the tumor cells within 10 rain of incubation with TNP-BSA. The cytotoxic response generated by addition of the TNP-proteins to spleen cell cultures was found to be T-cell dependent at the effector phase, as shown by the sensitivity of the lytic phase to absorbed RAMB and complement. Furthermore, the response did not appear to be attributable to antibody-dependent cellular cytotoxicity. Three mechanisms were considered which could account for the generation of H-2-restricted, TNP-specific, cytotoxic T-cell effectors by the addition of soluble TNP-proteins. These include covalent linkage of activated TNP groups from the soluble proteins to cell surface components, macrophage processing of the soluble conjugates and presentation to the responding lymphocytes in association with H-2-coded self structures, or hydrophobic interaction of the TNP-proteins to cell surfaces. Results obtained from sodium dodecyl sulfate gel patterns indicating that cell-bound TNP was still linked to BSA, and the observation that phagocytic-depleted cells could interact with the soluble TNP-proteins and function as H-2-restricted targets, appear not to favor the first two proposed mechanisms.     

跟骨定量超声骨质测量参数与骨密度及骨组织形态计量学指标的关系

目的:分析跟骨定量超声骨质测量中各参数与骨密度及形态计量学指标的相关性。方法:选择2004-01/2005-12广州市第六人民医院和中山大学三院骨科小腿以上截肢患者38例,将其跟骨定量超声测定的超声振幅衰减平均值与健康青年人骨峰值进行比较,>-2.5 SD者为骨量正常组(12例),<-2.5 SD者为骨质疏松组(26例)。分别进行跟骨定量超声、双能X线骨密度测量仪及骨形态计量学测量,应用直线相关分析法分析跟骨定量超声测定中各参数与骨密度及骨组织形态计量学各指标的相关性。结果:38例全部进入结果分析。①骨质疏松组跟骨超声振幅衰减平均值和骨硬度指数值均小于骨量正常组(P<0.01)。②骨量正常组跟骨骨密度值显著高于骨质疏松组[(352±16),(233±14)mg/cm2,P<0.01]。③骨量正常组跟骨平均骨小梁间距或弥散度低于骨质疏松组而松质骨体积高于骨质疏松组(P<0.05)。④超声振幅衰减平均值和骨硬度指数与骨密度呈直线正相关(r=0.814,0.326,P<0.01,0.05)。⑤超声传播速度与骨小梁游离末端、平均骨小梁间距呈直线负相关(r=-0.688,-0.712,P<0.01),与小梁间连点数、松质骨体积呈直线正相关(r=0.672,0.794,P<0.01);骨硬度指数与平均骨小梁间距呈直线负相关(r=-0.358,P<0.05),与松质骨体积呈直线正相关(r=0.513,P<0.01)。结论:跟骨定量超声测量中,超声振幅衰减平均值能较好地反映骨的密度,超声传播速度能较好地反映骨的质量,而骨硬度指数能较综合地反映骨强度的改变。     

The Diurnal Variation of the Serum Iron Concentration

Observations made in an investigation of the diurnal variation of the serum iron concentration suggested that the diurnal variations of serum iron can be explained as a phenomenon secondary to the diurnal variation of the hemoglobin metabolism. This hypothesis is supported by parallel changes in the bilirubin and serum iron values.     

In vitro characterization of the human recombinant soluble granulocyte- macrophage colony-stimulating factor receptor

We have cloned, expressed, and partially purified a naturally occurring, truncated, soluble form of the human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor alpha subunit to investigate its biochemical and biologic properties. The soluble receptor species lacks the transmembrane and cytoplasmic domains that are presumably removed from the intact receptor cDNA by a mechanism of alternative splicing. The resulting soluble 55- to 60-kD glycosylated receptor species binds GM-CSF with a dissociation constant (kd) of 3.8 nmol/L. The soluble GM-CSF receptor successfully competes for GM-CSF binding not only with the transmembrane-anchored GM-CSF receptor alpha subunit but also with the native oligomeric high-affinity receptor complex. In addition, in human bone marrow colony-forming assays, the soluble GM-CSF receptor species can antagonize the activity of GM-CSF. Our data suggest that the soluble GM-CSF receptor may be capable of acting in vivo as a modulator of the biologic activity of GM-CSF.     

A Novel Schlemm's Canal Scaffold Increases Outflow Facility in a Human Anterior Segment Perfusion Model

Purpose. An intracanalicular scaffold (Hydrus microstent) designed to reduce intraocular pressure as a glaucoma treatment was tested in human anterior segments to determine changes in outflow facility (C). Methods. Human eyes with no history of ocular disease or surgeries were perfused within 49 hours of death. The anterior segments were isolated and connected to a perfusion system. Flow rates were measured at pressures of 10, 20, 30, and 40 mm Hg. The scaffold was inserted into Schlemm's canal of the experimental eye, while a control eye underwent a sham procedure. Flow rate measurements were repeated at the four pressure levels. Individual C values were computed by dividing the flow rate by its corresponding pressure, and by averaging the four individual C measurements. The change in C between control and experimental eyes was assessed by the ratio of the baseline and second C measurement. In two eyes, the placement of the scaffold was evaluated histologically. Results. After scaffold implantation in the experimental eyes, the average C increased significantly from baseline (n = 9, P < 0.05). Ratios of C at all pressure levels, except for 10 mm Hg, were significantly higher in experimental eyes (n = 9) than control eyes (P < 0.05, n = 7). Histologically, the scaffold dilated Schlemm's canal with no visible damage to the trabecular meshwork. Conclusions. The Hydrus Microstent provided an effective way to increase outflow facility in human eyes ex vivo.     

A longitudinal immunologic evaluation of hemophiliac patients

Over an average span of one year, we performed a prospective clinical and immunologic evaluation of 30 patients with hemophilia. No patient developed life-threatening opportunistic infection or malignancy; however, the immunologic abnormalities and lymphadenopathy initially present in nine patients (lymphadenopathy group) persisted. In addition, five patients, representing 24% of the initial group without lymphadenopathy, developed generalized lymphadenopathy (converter group). One episode of idiopathic thrombocytopenia (ITP) and one episode of staphylococcal sepsis occurred in this "converter" group; one episode of ITP also occurred in the lymphadenopathy group. Sixteen patients remained asymptomatic. At the time of the follow-up evaluation, those differences in mononuclear cell (MNC) percentages and numbers noted initially among the three hemophiliac groups were no longer present. Natural killer cell function alone or in the presence of biologic response modifiers was not different among hemophiliac and control groups. Before developing lymphadenopathy, the converter group of patients had significantly better lymphocyte mitogenic function than did the other two groups of patients with hemophilia. However, lymphocyte mitogenic responses of all groups of patients with hemophilia significantly deteriorated over the course of the study. The abnormal mitogenic responses noted in these patients was explained in part by higher levels of spontaneous suppressor cell activity in mononuclear cell preparations from patients with hemophilia. We conclude that long-term immunologic studies of this patient population requires both quantitative and qualitative evaluations. Our data show that patients with hemophilia have progressive dysfunction of cell- mediated immunity.     

Proliferation of human malignant hematopoietic cells in immunodeficient mice: suppression by antibody to pluripotent K-562 leukemia cells involves direct cytolysis and effector cells

Six human hematopoetic cell lines were successfully heterotransplanted into athymic (nude) and asplenic-athymic (lasat) neonatal mice. The tumors arising from leukemia and lymphoma cells could then be serially transplanted into adult nude mice. Seven days after the fourth serial mouse passage, each mouse was treated with goat immune gamma globulin against K-562 cells. One control group was treated similarly, but with nonimmune (normal) gamma globulin, while another control group was not treated. The goat gamma globulin was not toxic for nude and lasat mice, and the immune, but not the normal, gamma globulin suppressed local subcutaneous growth of myelosarcomas, lymphosarcomas, and Burkitt lymphoma cells. On the other hand, the growth of lung, breast, and prostatic carcinomas and a melanoma of human origin were not altered by the immune gamma globulin. Since suppression of cell growth occurred equally well in decomplemented mice, a complement-mediated cytotoxicity apparently cannot be considered as responsible for the abrogation. The Fab fragment of the immunoglobulin did not suppress the growth of the myelosarcomas. We conclude that antibody suppression of the in vivo proliferation was specific for malignant hematopoietic cells and that the Fc portion of IgG is necessary for in vivo cytolysis of leukemia cells. The most probable mechanisms are direct antibody cytolysis and antibody-dependent macrophage-mediated cytotoxicity.     

Expression of bcl-xL can confer a multidrug resistance phenotype

It has been suggested that genes that regulate apoptotic cell death may play an important role in determining the sensitivity of tumor cells to chemotherapy. We have recently cloned a member of the bcl-2 family, bcl- x. To test whether bcl-XL expression affects the sensitivity of tumor cells to chemotherapy, we have created stable cell lines overexpressing bcl-XL and have tested these cells for resistance to cell death induced by metabolic inhibitors and chemotherapeutic agents. Bcl-XL expression dramatically reduces the cytotoxicity of bleomycin, cisplatin, etoposide, vincristine, hygromycin B, and mycophenolic acid for up to 4 days in culture. Bcl-XL does not prevent cells from undergoing cell cycle arrest in response to these drugs, but rather prevents treated cells from undergoing apoptosis. Cell-cycle analysis on cells treated with the chemotherapeutic agents bleomycin, cisplatin, etoposide, and vincristine, show that the drugs cause growth arrest in different positions within the cell cycle. Bcl-XL expressing cells treated with chemotherapeutic drugs retain their proliferative ability after the drugs are removed. Interestingly, vincristine-treated cells expressing bcl-XL become polyploid after drug removal. These data show that bcl-XL protects cells from a wide variety of apoptotic stimuli, acts in multiple positions within the cell cycle, and confers a multidrug resistance phenotype. The ability of bcl-XL to prevent apoptotic cell death in response to chemotherapy-induced DNA damage and cell-cycle arrest may contribute to the accumulation of chromosomal aberrations within tumors. The expression of bcl-XL in tumor cells is likely to be an important indicator of chemotherapeutic efficacy.     

Bcl-x rather than Bcl-2 mediates CD40-dependent centrocyte survival in the germinal center

Both rapid B-cell proliferation and programmed cell death (PCD) occur during the differentiation and selection of B cells within the germinal center. To help elucidate the role of Bcl-x in B-cell antigen selection and PCD within the germinal center, we examined its expression in defined B-cell populations and by immunochemistry of tonsil tissue. Purified B-cell fractions enriched for centrocytes express high amounts of Bcl-x and relatively low amounts of Bcl-2, whereas fractions enriched for centroblasts lack significant levels of both proteins. Consistent with this observation, immunocytochemistry localized Bcl-x within cells scattered throughout the germinal center. Stimulation of tonsil B cells with either CD40 or Staphylococcus aureus Cowan increase bcl-x mRNA and protein levels. Treatment of a cell line with a germinal center phenotype (RAMOS) or the tonsillar B-cell centroblast fraction with CD40 rapidly increased Bcl-x levels and partially rescued B cells from PCD. These data suggest that Bcl-x rather than Bcl-2 may rescue centrocytes during selection in the germinal center.