Ontogeny of B-lymphocyte function. III. In vivo and in vitro studies on the ease of tolerance induction in B lymphocytes from fetal, neonatal, and adult mice

The ease of tolerance induction in B lymphocytes from fetal, neonatal, and adult mice was studied in vivo, in a cell transfer system, and in vitro. Three different tolerogens were used: ultracentrifuged BGG, DNP(6)-D-GL, and ultracentrifuged DNP(22)-BGG. Irradiated thymectomized mice were reconstituted with B cells from fetal or neonatal liver or adult spleen or bone marrow. The mice were injected with tolerogen 1 day later. They were given normal thymus cells and challenged with either BGG or DNP(44)-BGG between 4 and 14 days after tolerance induction. With BGG no difference in ease of B-cell tolerance induction was observed in mice reconstituted with B cells from 17-day fetal liver, neonatal liver, 8- day-old spleen, adult spleen, or adult bone marrow. B cells from 14-day fetal donors are relatively resistant to tolerance induction. In contrast, with DNP(6)-D-GL and DNP(22)-BGG B cells from neonatal donors were clearly more susceptible to tolerance induction than were B cells from adult donors. Comparable results were obtained in studies on tolerance induction in vitro. Neonatal B cells were more susceptible than adult B cells to tolerance induction upon culture with DNP(6)-D-GL or DNP(22)-BGG. However, neonatal and adult B cells were identical with respect to ease of tolerance induction in vitro with deaggregated BGG. The results suggest that there are multiple mechanisms for B-cell tolerance induction. Immature B cells appear to be more susceptible to tolerance induction by some mechanisms but not by others. It is suggested that immature B cells are more susceptible to tolerance induction with moderately polyvalent antigens such as hapten-carrier conjugates. With antigens like BGG which do not haverepeated epitopes no difference between mature and fetal B cells in regard to ease of tolerance induction is observed. These observations raise questions about the importance of relative ease of tolerance induction in immature B cells as a mechanism controlling the normal induction of self tolerance.     

Extradural cavernous haemangioma simulating a disc protrusion

Cavernous haemangiomas confined to the epidural space are rare and are therefore infrequently considered in the differential diagnosis of spinal epidural masses. In order to draw attention to this diagnosis, a case in which an epidural cavernous haemangioma simulates a lateral/foraminal disc protrusion is presented.     

A randomized, controlled trial of nurse home visiting to vulnerable families with newborns

OBJECTIVE: This project aimed to evaluate the impact of a home visiting programme that targeted families where the child, for environmental reasons, was at great risk of poor health and developmental outcomes. METHODOLOGY: Women in the immediate postpartum period were recruited to a randomized double-blind controlled trial on the basis of self-reported vulnerability factors and were randomly assigned to receive either a structured programme of nurse home visiting, supported by a social worker and paediatrician (n = 90), or assigned to a comparison group receiving standard community child health services (n = 91). Parenting stress and maternal depression were measured at enrollment and at 6 weeks. Preventive health behaviour, service satisfaction and home environment outcomes were tested at 6 weeks, as were child health outcomes. RESULTS: At six weeks, women receiving the home-based programme had significant reductions in postnatal depression screening scores as well as improvements in their experience of the parental role and improvement in the ability to maintain their own identity. Maternal-infant interactions were more likely to be positive, with significantly higher (better) scores in aspects of the home environment related to optimal development in children, particularly maternal-infant secure attachment. Intervention group mothers were significantly more satisfied with the community child health service. CONCLUSIONS: This form of intervention for families is effective in promoting secure maternal-infant attachment, preventing maternal mood disorder and is welcomed by the families receiving it. These findings may predict long-term benefits for the healthy development of children otherwise at risk of a range of poor health and development outcomes.     

cis-Retinoic acid stimulates the clonal growth of some myeloid leukemia cells in vitro

We studied the effects of cis-retinoic acid (cisRA) on the clonogenic growth of samples of leukemic cells from 35 patients with acute nonlymphocytic leukemia (ANLL). We observed significant inhibition of leukemic colony growth in 17 samples by 10(-7) to 10(-6)M cisRA. However, we found that retinoid exposure resulted in striking stimulation of clonal growth in ten samples at the same drug concentrations. With the exception of cases with promyelocytic features, there was no morphologic or functional evidence that cisRA induced the leukemic blasts to differentiate. Both inhibition and stimulation were dose-dependent and observable at pharmacologically achievable levels of cisRA. Leukemic cells with monocytic features more frequently demonstrated a stimulatory response than did those without monocytic features. Depletion of T lymphocytes and monocytes did not alter the type of growth response. Assays for cellular retinoic acid- binding protein (CRABP) were performed on five samples (two with inhibitory growth responses, two with stimulatory responses, and one with no growth) and failed to reveal detectable levels of CRABP in any case. The addition of cisRA to liquid suspensions of leukemic cells produced no significant change in the number of viable cells. We conclude that the effects of cisRA on leukemic colony growth are not cytotoxic and not mediated by T lymphocytes, monocytes, or CRABP. More importantly, cisRA appears to enhance the growth of certain human leukemia cells in vitro. Taking into account the increasing use of retinoids in clinical trials for patients with leukemia, the latter findings may represent a significant cautionary note.     

Proton magnetic resonance spectroscopy in the brain: report of AAPM MR Task Group #9

AAPM Magnetic Resonance Task Group #9 on proton magnetic resonance spectroscopy (MRS) in the brain was formed to provide a reference document for acquiring and processing proton (1H) MRS acquired from brain tissue. MRS is becoming a common adjunct to magnetic resonance imaging (MRI), especially for the differential diagnosis of tumors in the brain. Even though MR imaging is an offshoot of MR spectroscopy, clinical medical physicists familiar with MRI may not be familiar with many of the common practical issues regarding MRS. Numerous research laboratories perform in vivo MRS on other magnetic nuclei, such as 31P, 13C, and 19F. However, most commercial MR scanners are generally only capable of spectroscopy using the signals from protons. Therefore this paper is of limited scope, giving an overview of technical issues that are important to clinical proton MRS, discussing some common clinical MRS problems, and suggesting how they might be resolved. Some fundamental issues covered in this paper are common to many forms of magnetic resonance spectroscopy and are written as an introduction for the reader to these methods. These topics include shimming, eddy currents, spatial localization, solvent saturation, and post-processing methods. The document also provides an extensive review of the literature to guide the practicing medical physicist to resources that may be useful for dealing with issues not covered in the current article.     

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。     

特定培养基条件下大鼠脂肪间充质干细胞体外定向软骨细胞的分化

目的:体外诱导大鼠脂肪间充质干细胞向软骨细胞分化,并对分化细胞进行相应鉴定,观察脂肪间充质干细胞作为软骨组织工程种子细胞的可行性。方法:实验于2005-05/2006-05在湘雅医院中心实验室完成。①取大鼠腹股沟脂肪,消化分离脂肪间充质干细胞进行原代培养。②流式细胞仪检测第3代脂肪间充质干细胞表面CD29,CD34,CD44表达。③传3代细胞进行微团培养1d,换用含体积分数为0.01的新生牛血清、10μg/L的转化生长因子β1、6.25mg/L的胰岛素、6.25mg/L的转铁蛋白、1×10-7mol/L的地塞米松、50mg/L的维生素C的高糖DMEM诱导液,为特定培养条件。④在诱导后4,7,14d应用阿尔新兰染色、蕃红O/固绿染色和Ⅱ型胶原免疫细胞化学评价软骨形成情况。⑤反转录-聚合酶链反应在诱导后0和14d检测脂肪间充质干细胞前Ⅱ型胶原蛋白和聚集蛋白聚糖mRNA的表达。结果:①脂肪间充质干细胞的形态特征:原代脂肪间充质干细胞呈短梭形、梭形及多角形,3代后呈均一长梭形。②脂肪间充质干细胞的表面标志鉴定:脂肪间充质干细胞表达CD29,CD44,基本不表达CD34。③脂肪间充质干细胞诱导后的形态特征:脂肪间充质干细胞经诱导后,由长梭形转变为三角形、多角形或短梭形,逐渐聚集成结节。④脂肪间充质干细胞诱导后的细胞化学染色结果:诱导后脂肪间充质干细胞胞外基质阿尔新兰染色、蕃红O/固绿染色、和Ⅱ型胶原免疫细胞化学着色阳性。⑤反转录-聚合酶链反应检测结果:反转录-聚合酶链反应检测未诱导脂肪间充质干细胞不表达前Ⅱ型胶原蛋白和聚集蛋白聚糖mRNA基因,而诱导后的脂肪间充质干细胞表达前Ⅱ型胶原蛋白和聚集蛋白聚糖mRNA基因。结论:脂肪间充质干细胞在由转化生长因子1、胰岛素、转铁蛋白等组成的特定培养基条件诱导下可以定向软骨细胞分化。     

后交叉韧带作为间接MR影像在前交叉韧带损伤中的诊断价值

目的评价后交叉韧带(PCL)作为间接MR影像在前交叉韧带(ACL)损伤中的诊断价值.方法回顾分析78例经关节镜证实的膝关节MRI资料,其中ACL损伤33例,正常45例.盲法分析MR影像的以下PCL参数:PCL线、PCL角和PCL指数.结果阳性PCL线诊断ACL 损伤的敏感性和特异性分别是75.6% 和 97.8%,PCL角小于109°分别是66.7% 和96.6%.ACL 损伤的PCL角为(102±10.1)°,正常时PCL角为(116±9.8)°(P< 0.001).ACL 损伤时PCL指数为3.76±0.93,正常为4.95±0.63(P<0.01).结论 PCL角小于109°和阳性PCL 线的高特异性说明可以用其诊断ACL损伤.PCL角度和PCL指数越小,ACL损伤的可能性越大.     

冠状动脉运动规律的磁共振电影成像研究

目的利用磁共振电影成像研究冠状动脉的运动规律.方法选取不同心率的志愿者35例,使用电影成像序列显示冠状动脉断面的运动轨迹,以5% R-R间期为标准化时间单位(NTU),分析冠状动脉运动轨迹和速度的特征.结果冠状动脉各分支的运动轨迹存在个体差异.当心率小于75 bpm时,RCA和LCX在ECG触发延迟75% R-R的舒张中期和40% R-R的收缩末期运动速度小于3 mm/NTU,LAD在整个心动周期运动速度基本都小于3 mm/NTU.结论心率小于75 bpm时,建议选择舒张中期进行冠状动脉的断层采样或者重建.     

正常舟月韧带厚度超声与MRI研究

目的提供舟月韧带厚度(SLLT)超声测量正常值,评价超声测量舟月韧带厚度的准确性.方法用超声高频探头探查200只正常手腕,与MRI测量其中的30人60只手腕比较.记录超声和MRI图像上SLLT测值.结果舟月韧带在背侧部正中位声像图最清晰.男、女性舟月韧带背侧部厚度(SLLTd)分别为(2.18±0.35) mm和(1.99±0.23) mm.超声与MRI在测量SLLT相关性比较呈直线相关(P<0.01).结论超声能够清晰显示并准确测量舟月韧带的厚度.