严重烧伤延迟复苏大鼠远隔脏器的能量代谢紊乱

目的:观察延迟复苏大鼠远隔脏器的能量代谢情况。方法:实验于2001-05/2004-08在长海医院烧伤中心实验室完成。取24只SD大鼠随机分为假烫组、烧伤组、早期复苏组、延迟复苏组4组,每组6只。①除假烫组外,其他3组大鼠用恒温水烫仪100℃水烫12s,制成体表面积30%Ⅲ度烧伤模型(病理证实),假烫组于37℃水中假烫12s。②伤后假烫组和烧伤组不液体复苏,早期复苏组在伤后30,90min分别用30mL/kg乳酸林格氏液腹腔注射液体复苏;延迟复苏组大鼠在伤后6,7h分别用40mL/kg乳酸林格氏液腹腔注射液体复苏。③所有大鼠伤后9h取材,测定肺、心、肝、肾组织Na -K -ATP酶活性,Ca2 -Mg2 -ATP酶活性,髓过氧化物酶活性,一氧化氮代谢产物量。结果:24只大鼠进入结果分析。①烧伤后9h延迟复苏组大鼠肺、心、肝、肾组织的Na -K -ATP酶活性分别为(0.16±0.03),(2.82±0.41),(1.96±0.29),(3.94±0.40)μkat/g,明显低于烧伤组和烧伤后早期复苏组(P<0.05或0.01)。②烧伤后9h延迟复苏组大鼠肺、心、肝、肾组织的Ca2 -Mg2 -ATP酶活性分别为(0.40±0.08),(3.71±0.70),(2.44±0.56),(2.39±0.57)μkat/g,也明显低于烧伤组和烧伤后早期复苏组(P<0.05或0.01)。③烧伤后9h延迟复苏组大鼠肺、心、肝、肾组织的髓过氧化物酶活性分别为(9.91±1.13),(0.80±0.09),(0.75±0.08),(0.76±0.09)μkat/g,明显高于烧伤组和烧伤后早期复苏组(P<0.05或0.01)。④烧伤后9h延迟复苏组大鼠肺、心、肝、肾组织中一氧化氮代谢产物量明显少于烧伤组和烧伤后早期复苏组(P<0.01)。结论:烧伤延迟复苏大鼠远隔脏器存在能量代谢紊乱,中性粒细胞积聚和一氧化氮产生减少可能是其重要机制。     

大鼠脂肪和骨髓来源间充质干细胞基本生物学特征的比较

目的:分离大鼠脂肪和骨髓来源的间充质干细胞,比较两种间充质干细胞的生物学特征。方法:实验于2003-09/2006-11在广州市第一人民医院、湘雅医院中心实验室完成。取SD大鼠的股骨、胫骨、肱骨及腹股沟处脂肪垫进行骨髓间充质干细胞与脂肪间充质干细胞的分离。将骨髓间充质干细胞和脂肪间充质干细胞在含10%血清,1%双抗的低糖DMEM培养基,37℃、体积分数为0.05的CO2条件下进行培养。在细胞达到80%～90%融合时,使用0.25%胰酶消化传代。传代至第3代使用倒置显微镜观察骨髓和脂肪两种不同来源细胞的传代后的形态、贴壁、生长增殖、集落等情况。取消化传3代的两种细胞分别制成单细胞悬液进行细胞贴壁率的检测,贴壁率=贴壁细胞总数/接种细胞总数×100%。取第2代和第5代骨髓间充质干细胞和脂肪间充质干细胞以1×107L-1密度培养。每天同一时间,随机抽取5孔细胞,加入5%噻唑兰20μL/孔,培养4～6h,吸出孔内液体,每孔加150μL二甲基亚砜震荡10min,酶联免疫测定仪测定波长490nm处的吸光度,取5孔吸光度的均值,以时间为横坐标,吸光度值为纵坐标,绘制生长曲线。采用流式细胞仪检测细胞表面CD29、CD34、CD44标记,免疫化学检测细胞CD29、CD34、CD44。结果:①在单位质量骨髓和脂肪组织中获得的间充质干细胞数量相当。两种细胞形态均为条索样,呈成纤维细胞形态。②应用直线相关分析,考察骨髓贴壁率与脂肪贴壁率之间的关系,相关系数r=0.999,决定系数r2=0.997(F=5862.949,P<0.001),两贴壁率之间有直线相关关系,不同的时间点两种细胞的贴壁率相似,并且有同向变化的趋势。③脂肪间充质干细胞的增殖能力与骨髓间充质干细胞相当。④脂肪间充质干细胞和骨髓间充质干细胞表面表达CD29、CD44,不表达CD34。结论:自大鼠脂肪中可提取出与骨髓间充质干细胞生物学特征类似的脂肪间充质干细胞。     

纳米羟基磷灰石对人骨髓基质干细胞体外成骨活性的影响

目的：观察人骨髓基质干细胞在纳米羟基磷灰石材料上的生长、分化特点以及成骨细胞形态. 方法：实验于2004-03/2005-07在中南大学湘雅医院医学实验室完成.①实验方法：采用密度梯度离心的方法分离人骨髓基质干细胞,加入含体积分数为0.1的新生牛血清的低糖DMEM完全培养基中作原代培养,细胞长至90%汇合时传代,取培养第3代细胞接种于纳米羟基磷灰石（卫生部肝胆肠研究中心纳米课题组提供）表面,并加入含1 mmol/L地塞米松、50 mg/L维生素C、10 mmol/L β-甘油磷酸钠的培养基中诱导分化、培养.②观察指标：复合培养第2,4,6,8天后采用MTT法检测细胞增殖情况;复合培养7 d后行钙-钴法成骨细胞染色观察细胞分化情况;培养8 d后应用扫描电子显微镜观察细胞在材料上的生长情况. 结果：MTT法检测出的吸光值随着培养时间的增加而增大（P＜0.05）;经加入特定的成骨诱导体系培养7 d后,附着于材料的骨髓基质干细胞具有典型的成骨细胞形态,经钙-钴法染色后细胞胞浆中可见灰黑色颗粒或块状沉淀的阳性反应,细胞形态也多呈多角形或短矩形;培养8 d后扫描电镜可观察到材料孔隙内有细胞长入. 结论：人骨髓基质干细胞在纳米羟基磷灰石材料上生长良好,提示纳米羟基磷灰石适于骨髓基质干细胞的生长、分化,可作为骨组织工程的细胞外支架材料.     

Phenotypic heterogeneity of spontaneous lymphomas of CWD mice

Animals of the inbred mouse strain, CWD, express endogenous murine leukemia viruses early in life and have a high incidence of spontaneous neoplasms. We found that approximately one half of these animals died of malignant lymphoma by the age of 16 months. Splenic enlargement was seen in all mice, but thymic involvement was unusual. One half of the CWD tumors were diffuse lymphoblastic or immunoblastic lymphomas while the remainder were large cell, small cell, or mixed cell lymphomas. Analysis of DNAs from 12 tumors for immunoglobulin and T-cell receptor gene rearrangements revealed that all six of the lymphoblastic and immunoblastic lymphomas were of T-cell origin, as was one tumor of small cleaved cells. Four of the others were clonal B-cell lymphomas and one was of uncertain lineage. Assays of a limited number of tumors for the expression of the Thy 1.2 and IgM molecules confirmed the diversity in the cellular phenotype. The results indicate that CWD mice develop primarily splenic lymphomas with an unusual degree of heterogeneity in the tumor cell phenotypes as compared with the thymic lymphomas found in other high leukemia strains. The CWD strain is a useful new model for studies of retroviral leukemogenesis and the relationship between the histopathology and immunophenotype of malignant lymphomas.     

Point mutations in the conserved box 1 region inactivate the human granulocyte colony-stimulating factor receptor for growth signal transduction and tyrosine phosphorylation of p75c-rel

The human granulocyte colony-stimulating factor receptor (hG-CSFR) belongs to the cytokine receptor superfamily. As with other members of this family, the cytoplasmic domain of hG-CSFR lacks intrinsic tyrosine kinase activity. To identify critical regions mediating growth signal transduction by hG-CSFR, deletions or site-directed amino acid substitutions were introduced into the cytoplasmic domain of hG-CSFR, and the mutant cDNAs were transfected into the murine interleukin-3 (IL- 3)-dependent Ba/F3 and FDCP cell lines. Truncation of the carboxy- terminal end of the receptor to the membrane-proximal 53 amino acids of the cytoplasmic domain, which retained the conserved Box 1 and Box 2 sequence motifs, decreased the ability of hG-CSFR to transduce G-CSF- mediated growth signals without an associated loss in receptor binding affinity. Substitution of proline by alanine at amino acid positions 639 and 641 within Box 1 completely abolished the G-CSF-mediated growth signal. Rapid induction of tyrosine phosphorylation of several cellular proteins, including a 75-kD protein (p75) identified as c-rel, was an early event associated with transduction of proliferative signals by hG- CSFR in Ba/F3 transfectants. Mutant receptors containing Pro-to-Ala substitutions that inactivated the receptor for mitogenic activity also inactivated the receptor for tyrosine-specific phosphorylation of p75. These results show that the conserved Box 1 sequence motif (amino acids 634 to 641) is critical for mitogenesis and activation of cellular tyrosine kinases by hG-CSFR.     

The efficacy of CD3 x CD19 bispecific monoclonal antibody (BsAb) in a clonogenic assay: the effect of repeated addition of BsAb and interleukin-2

To evaluate the potency by which human T cells are targeted and activated by bispecific monoclonal antibodies (BsAbs) to lyse tumor cells, a clonogenic assay was developed. The efficacy of a CD3 x CD19 BsAb binding to both the CD3 T-cell antigen and the CD19 B-cell antigen was already proven in 51Cr-release assays and in 3-day activation cultures. To achieve more quantitative results, a 14-day clonogenic assay, based on limiting-dilution, was performed for the determination of the initial and residual number of clonogenic units obtained with a CD19+ pre-pre-B acute lymphoblastic leukemia (ALL-B) cell line. Elimination of up to 5 logs of ALL-B cells by freshly isolated peripheral blood mononuclear cells (PBMCs) cultured with BsAb plus interleukin-2 (IL-2) could be detected. The presence of human IgG did not abolish the effect. Repeated addition of each of the two agents was necessary, because a single treatment produced only a 1- to 2-log kill. CD3 monoclonal antibody and IL-2 stimulation ("lymphokine-activated killer cell" conditions) resulted in only a 2-log kill. The number of T cells proved critical in lysis of ALL-B cells, with a 5-log kill using a T-cell:B-cell ratio of 3:1 but with only a 1-log kill using a ratio of 1:1. PBMCs isolated from patients with non-Hodgkin's lymphoma, both in relapse or remission, proved to be as competent as those from healthy donors in removing ALL-B cells. This clonogenic assay shows the importance of repeated administration of CD3 x CD19 BsAb and IL-2 and offers the possibility to compare it with other therapies in B-cell malignancy.