Isolation of myeloid progenitor cells from peripheral blood of chronic myelogenous leukemia patients

Myeloid progenitor cells (colony- and cluster-forming cells in semisolid medium, CFU-GM) were purified from the peripheral blood of chronic myelogenous leukemia (CML) patients. Lymphocytes, monocytes, and most immature myeloid cells were simultaneously depleted with specific monoclonal antibodies using an erythrocyte rosette technique for cell separation. Cells expressing Ia-like antigen were then selected from the residual cell population. Day 7 CFU-GM were enriched 44--116-fold in the IA+ cell fraction, when compared to the unseparated cells, and up to 47% of the cells could form a myeloid colony or cluster in culture. This cell fraction contained up to 92% undifferentiated blasts, with the remainder mostly promyelocytes. The enriched CFU-GM cells were dependent on an exogenous supply of colony- stimulating factor for growth, and colony formation was linear with cell concentration over a large range (10(4)-10(1) cells/ml). This technique of rosette depletion and enrichment with specific monoclonal antibodies provides a unique method for purifying a homogenous population of myeloid precursor cells with defined surface antigen characteristics.     

A carboxyl terminal truncation mutant of CD36 is secreted and binds thrombospondin: evidence for a single transmembrane domain

CD36 has been implicated in several intracellular signalling events, including platelet and monocyte activation, and receptor-mediated internalization of bound ligands such as oxidized low-density lipoprotein and apoptotic neutrophils. These processes are presumably mediated by the intracytoplasmic domain(s) of the molecule. By analysis of hydrophobicity plots and by analogy to rat LIMPII, which has a 60% homology to CD36, a two-transmembrane domain model has been proposed. To characterize the structure-function relationships of CD36 involved in transducing the signal, we have defined the number of transmembrane and intracellular domains experimentally using a mutagenesis approach. A truncated CD36 cDNA was constructed that encodes a protein that terminates just proximal to the putative C-terminal transmembrane domain. This mutant was cloned into eukaryotic expression plasmid vectors to generate short-term and stable transfected cells. Our results indicate that the truncated mutant is secreted by the transfectants into the postculture medium, indicating that there is only one transmembrane domain in CD36, which is present at the C- terminal end. The soluble secreted protein from all of these cells is functional as indicated by its binding to thrombospondin.     

Reduced neutron production through use of a flattening-filter-free accelerator

PURPOSE: To measure and compare neutron fluence around an accelerator operating at 18 MV, both with the flattening filter present (FF mode) and absent (flattening-filter-free [FFF] mode). METHODS AND MATERIALS: The neutron fluence was measured at several locations in the patient plane using gold foil activation in neutron moderators. Differences in neutron fluence between the FF and FFF mode were assessed in three frameworks: (1) measured per monitor unit of machine-on time, (2) determined per dose on the central axis, and (3) determined for a complete course of prostate intensity-modulated radiotherapy. RESULTS: Neutron fluence per monitor unit was approximately 20% lower when the accelerator was operated in the FFF mode than when it was in FF mode. The total amount of neutron fluence that would be obtained during the entire course of prostate intensity-modulate radiotherapy was 69% lower when the accelerator was operated in the FFF mode than when it was in the FF mode. This reduction in neutron fluence would correspond to a drastic reduction in the neutron dose equivalent received by the patient as a byproduct of high-energy radiotherapy. It would also correspond to a reduction in activation within the treatment vault and subsequent exposure to radiation therapists. CONCLUSION: When feasible, operating the accelerator without a FF will benefit both patients and radiation therapists by reducing the number of unwanted neutrons and resultant exposure. This reduces the risk of negative effects from such exposure (e.g., second cancers).     

Co-Infections with Cytomegalovirus and Human Herpesvirus Type 7 in Adult Polish Allogeneic Haematopoietic Stem Cell Transplant Recipients

Human herpesvirus 7 (HHV-7) is widespread around the world and may also be a possible cofactor for cytomegalovirus (CMV) infection in haematopoietic stem cell transplant (HSCT) recipients. In case of viral diseases where specific treatment is available, real-time PCR assays constitute reliable diagnostic tools enabling timely initiation of appropriate therapy and rapid assessment of the efficacy of antiviral treatment strategies. The presence of CMV and HHV-7 was confirmed by the detection of viral DNA isolated from 1,027 plasma samples. A group of 69 allogeneic HSCT (alloHSCT) recipients was examined in early post-transplant period using quantitative real-time PCR methods. Within the study period, 62 % of patients had at least once CMV DNA-emia, while HHV-7 DNA was found in 43 % of subjects. Co-infection between these β-herpesviruses was detected in the plasma samples collected from 18 patients (26 %). Patients with concomitant HHV-7 DNA-emia had significantly higher number of CMV DNA copies compared with those without HHV-7 infection (1986 vs. 432 copies/ml, p < 0.001) but there was no difference in duration of CMV DNA-emia between these groups. On the other hand, while the load of HHV-7 DNA was comparable between patients with CMV DNA-emia and without CMV DNA-emia, the duration of HHV-7 DNA-emia was significantly longer in the first group (38.5 vs. 14 days, p < 0.001). HHV-7 DNA-emia is very frequently detected in Polish alloHSCT recipients. In those, who have subsequent CMV reactivation, the coexistence of the viruses may negatively affect the kinetics of infection with either of them. Therefore the investigation of concomitant HHV-7 DNA-emia could affect the prognosis of post-transplant patients suffering from CMV reactivation.     

Measures and models for causal inference in cross-sectional studies: arguments for the appropriateness of the prevalence odds ratio and related logistic regression

Background  

Several papers have discussed which effect measures are appropriate to capture the contrast between exposure groups in cross-sectional studies, and which related multivariate models are suitable. Although some have favored the Prevalence Ratio over the Prevalence Odds Ratio -- thus suggesting the use of log-binomial or robust Poisson instead of the logistic regression models -- this debate is still far from settled and requires close scrutiny.     

可变误差多面体法用于多种维生素的同时测定

本文基于对多元校正分析模型的简要讨论,探索了应用可变误差多面体法同时测定维生索B₁,B₂,B₆和烟酰胺的可行性。其结果准确度和精密度均较满意。维生素B₁,B₂,B₆及烟酰胺的回收率分别是99.8±0.9%(CV),100.1±0.8%(CV),100.2±2.1%,100.1±0.7%(CV)。结果表明,通过公式K_S=A_SC_S^T(C_SC_S^T)^-1计算校正系数矩阵K_S,并结合可变误差多面体法这一直接求解方法,能有效地提高分析结果的准确度,克服组分间的交互作用及病态,是多元校正分析的较佳策略之一。     

苦参碱的正性肌力作用及与细胞外钙的关系

苦参碱(matrine,Ma)来源于苦豆子Sophora alopecuroides L.)。Ma有加强豚鼠乳头肌收缩的作用,对豚鼠心房亦有明显正性肌力作用。本文对Ma的正性肌力作用与细胞外钙的关系进行了研究。Ma (mp 75.5～77.5℃)为淡黄色粉末结晶,为宁夏盐池制药厂产品。