Full-length but not truncated CD34 inhibits hematopoietic cell differentiation of M1 cells

CD34 is expressed on human and murine hematopoietic stem and progenitor cells and its clinical usefulness for isolation of stem/progenitor cells has been well established. Although expression of CD34 is regulated in a developmental stage-specific manner, the function of CD34 is not known. Recently we have shown that both a full-length and truncated form of CD34 protein is expressed by hematopoietic cells (Blood 84:691, 1994). To test whether failure to suppress either form of CD34 could affect terminal myeloid differentiation, we constitutively expressed these CD34 proteins in murine M1 myeloid leukemia cells, which can be terminally differentiated to macrophages by treatment with interleukin-6 of leukemia inhibitory factor. Surprisingly our results show that forced expression of the full-length but not the truncated form of CD34 impedes terminal differentiation by these agents. Because the difference between the two forms of CD34 protein resides in the length of their respective cytoplasmic tail domains, our findings strongly suggest that the cytoplasmic domain region of full-length CD34 is responsible for the observed maturation arrest phenotype. These findings suggest a potential negative regulatory role for full-length CD34 in hematopoietic cell differentiation and may explain, at least in part, the block in maturation observed in CD34+ acute myeloid leukemia.     

Assessment of aldehyde dehydrogenase in viable cells

Cytosolic aldehyde dehydrogenase (ALDH), an enzyme responsible for oxidizing intracellular aldehydes, has an important role in ethanol, vitamin A, and cyclophosphamide metabolism. High expression of this enzyme in primitive stem cells from multiple tissues, including bone marrow and intestine, appears to be an important mechanism by which these cells are resistant to cyclophosphamide. However, although hematopoietic stem cells (HSC) express high levels of cytosolic ALDH, isolating viable HSC by their ALDH expression has not been possible because ALDH is an intracellular protein. We found that a fluorescent aldehyde, dansyl aminoacetaldehyde (DAAA), could be used in flow cytometry experiments to isolate viable mouse and human cells based on their ALDH content. The level of dansyl fluorescence exhibited by cells after incubation with DAAA paralleled cytosolic ALDH levels determined by Western blotting and the sensitivity of the cells to cyclophosphamide. Moreover, DAAA appeared to be a more sensitive means of assessing cytosolic ALDH levels than Western blotting. Bone marrow progenitors treated with DAAA proliferated normally. Furthermore, marrow cells expressing high levels of dansyl fluorescence after incubation with DAAA were enriched for hematopoietic progenitors. The ability to isolate viable cells that express high levels of cytosolic ALDH could be an important component of methodology for identifying and purifying HSC and for studying cyclophosphamide-resistant tumor cell populations.     

对配偶婚外情的决定宽恕和情感宽恕与心理健康的关系

目的:考察因配偶婚外情而求助热线的个案决定宽恕与情感宽恕与心理健康状况的关系。方法:采用问卷调查法对82名热线求助个案进行测查。结果:①求助个案自尊和生活满意度处于中等水平,而抑郁和沉思处于较高水平;②决定宽恕显著正向预测生活满意度,情感宽恕显著负向预测抑郁心境和沉思;③高决定宽恕低情感宽恕组的生活满意度显著高于低决定宽恕低情感宽恕组;高决定宽恕高情感宽恕组的沉思显著低于另外两组。结论:决定宽恕和情感宽恕对个体心理健康有积极影响,婚姻家庭治疗师或其他专业人士应关注两者在婚外恋创伤心理治疗中的重要意义。     

Deleterious effect of brachtherary on vasomotor response to exercise

Background In-stent restenosis(ISR) is one of the major drawbacks of coronary stenting. Intraeoronary radiation therapy (RT)is effective in reducing excessive neointimal proliferation but long term results with regard to vascular integrity and vasomotor responsiveness are largely tmknown. Thus, the present study was to determine the exercise-induced vasomotor response of inadiated coronary arteries.     

Occupational voice demands and their impact on the call-centre industry

Background  

Within the last decade there has been a growth in the call-centre industry in the UK, with a growing awareness of the voice as an important tool for successful communication. Occupational voice problems such as occupational dysphonia, in a business which relies on healthy, effective voice as the primary professional communication tool, may threaten working ability and occupational health and safety of workers. While previous studies of telephone call-agents have reported a range of voice symptoms and functional vocal health problems, there have been no studies investigating the use and impact of vocal performance in the communication industry within the UK. This study aims to address a significant gap in the evidence-base of occupational health and safety research. The objectives of the study are: 1. to investigate the work context and vocal communication demands for call-agents; 2. to evaluate call-agents' vocal health, awareness and performance; and 3. to identify key risks and training needs for employees and employers within call-centres.     

Osteosarcoma: use of MR imaging and MR spectroscopy in clinical decision making

Magnetic resonance (MR) imaging was performed on 14 patients with histologically proved osteosarcoma (mean age, 14.4 years). There was excellent correlation of intramedullary tumor extent as determined with MR imaging and pathologic examination (r = 99%). This was facilitated by the presence of a chemical shift artifact at the tumor-marrow interface on the T1-weighted images. The correlation between CT and pathologic findings was not as good (r = 84%). In a single patient, however, a 10-cm length of sclerotic bone was incorrectly interpreted as being tumor. If this case is excluded, the correlation between CT and pathologic findings improves significantly (r = 96%). T2-weighted images were optimal in demonstrating soft-tissue bulk and breach of the epiphysis or cortex. Vascular involvement was also readily defined. The T2 value of the tumor soft-tissue component decreased in patients who were deemed to have responded well to therapy. Two patients with very high T2 values after chemotherapy developed wide-spread metastatic disease and died. Phosphorus-31 MR spectroscopy of five patients with osteosarcoma showed elevated levels of phosphomonoesters (PMEs), inorganic phosphate (Pi), and phosphodiesters (PDEs). PME and PDE peak areas decreased in three patients after chemotherapy, while Pi peak areas increased.     

Synthesis of cystine peptides 21–25/70–73 and 35–39/56–59 of the β-subunit of human choriogonadotropin

Syntheses of two asymmetrical cystine peptides with the amino acid residues 21–25/70–73 and 35–39/56–59, based on the linear amino acid sequence and the disulfide bond assignment in the β-subunit of human choriogonadotropin (hCG-β), are described. S-trityl and S-acetamidomethyl peptide fragments of each cystine peptide were prepared in solution phase and were subjected to oxidation with I₂/MeOH to form the disulfide bridge. The cystine peptides were characterized by their amino acid analyses and fast atom bombardment mass spectrometry. Immunological characterization by several homologous radioimmunoas-say systems showed that peptide 21–25/70–73 had significant hCG, hCG-β, and hLH activities while peptide 35–39/56–59 failed to reveal any immunoreactivity.     

Ankle: surface coil MR imaging at 1.5 T

High-field surface coil magnetic resonance (MR) images were obtained of 12 ankles: two from healthy volunteers, seven from patients, and three from fresh cadavers. The cadaver ankles were sectioned in the coronal, sagittal, and axial planes for direct comparison with the MR images. Plain film confirmation of pathologic conditions was obtained in all patients, and five underwent arthroscopy or surgery, or both. MR imaging provided excellent delineation of ligaments and cartilaginous structures in all cases.