Defining the domains of type I collagen involved in heparin- binding and endothelial tube formation

Cell surface heparan sulfate proteoglycan (HSPG) interactions with type I collagen may be a ubiquitous cell adhesion mechanism. However, the HSPG binding sites on type I collagen are unknown. Previously we mapped heparin binding to the vicinity of the type I collagen N terminus by electron microscopy. The present study has identified type I collagen sequences used for heparin binding and endothelial cell–collagen interactions. Using affinity coelectrophoresis, we found heparin to bind as follows: to type I collagen with high affinity (K_d ≈ 150 nM); triple-helical peptides (THPs) including the basic N-terminal sequence α1(I)87–92, KGHRGF, with intermediate affinities (K_d ≈ 2 μM); and THPs including other collagenous sequences, or single-stranded sequences, negligibly (K_d 10 μM). Thus, heparin–type I collagen binding likely relies on an N-terminal basic triple-helical domain represented once within each monomer, and at multiple sites within fibrils. We next defined the features of type I collagen necessary for angiogenesis in a system in which type I collagen and heparin rapidly induce endothelial tube formation in vitro. When peptides, denatured or monomeric type I collagen, or type V collagen was substituted for type I collagen, no tubes formed. However, when peptides and type I collagen were tested together, only the most heparin-avid THPs inhibited tube formation, likely by influencing cell interactions with collagen–heparin complexes. Thus, induction of endothelial tube morphogenesis by type I collagen may depend upon its triple-helical and fibrillar conformations and on the N-terminal heparin-binding site identified here.     

Low transplant-related mortality after second allogeneic peripheral blood stem cell transplant with reduced-intensity conditioning in adult patients who have failed a prior autologous transplant

Standard allogeneic stem cell transplantation (SCT) has been associated with a high transplant-related mortality (TRM) in patients who have failed a prior autologous SCT (ASCT). Reduced-intensity conditioning (RIC) regimens may reduce the toxicities and TRM of traditional myeloablative transplants. We report 46 adults who received a RIC peripheral blood SCT from an HLA-identical sibling in two multicenter prospective studies. The median interval between ASCT and allograft was 16 months, and the patients were allografted due to disease progression (n = 43) and/or secondary myelodysplasia (n = 4). Conditioning regimens consisted of fludarabine plus melphalan (n = 41) or busulphan (n = 5). The 100-day incidence of grade II-IV acute graft-versus-host disease (GVHD) was 42% (24% grade III-IV), and 10/30 evaluable patients developed chronic extensive GVHD. Early complete donor chimerism in bone marrow and peripheral blood was observed in 35/42 (83%) patients, and 16 evaluable patients had complete chimerism 1 year post transplant. With a median follow-up of 358 days (450 in 29 survivors), the 1-year incidence of TRM was 24%, and the 1-year overall (OS) and progression-free survival were 63% and 57%, respectively. Patients who had chemorefractory/ progressive disease, a low performance status or received GVHD prophylaxis with cyclosporine A alone (n = 32) had a 1-year TRM of 35% and an OS of 46%, while patients who had none of these characteristics (n = 32) had a 1-year TRM of 35% and an OS of 46% while patients who had none of these characteristics (n = 14) had a TRM of 0% and an OS of 100%. Our results suggest that adult patients who fail a prior ASCT can be salvaged with a RIC allogeneic PBSCT with a low risk of TRM, although patient selection has a profound influence on early outcome.     

Ligand-dependent transformation by the receptor for human granulocyte/macrophage colony-stimulating factor and tyrosine phosphorylation of the receptor beta subunit.

The receptor for human granulocyte/macrophage colony-stimulating factor (hGMR) is composed of two subunits, alpha and beta, which are both required for high-affinity binding of the ligand. To examine the transforming potential of hGMR, we have transfected cDNAs encoding the receptor alpha and beta subunits into NIH 3T3 cells, which normally do not express GMRs. Introduction of the receptor subunits into these cells resulted in focal transformation, which was dependent on the presence of human granulocyte/macrophage colony-stimulating factor (hGM-CSF) in the culture medium. No transformation was observed when hGM-CSF was replaced with other growth factors such as human epidermal growth factor or human interleukin 3 or when cells were transfected with the alpha or beta subunit alone. Individual conditional transformants isolated after transfection expressed functional hGMRs, were susceptible to transformation by picomolar levels of the ligand, and were capable of anchorage-independent growth in soft agar in the presence but not in the absence of hGM-CSF. Biochemical analysis showed that treatment of these cells with hGM-CSF caused a rapid phosphorylation of the beta subunit and other cellular proteins on tyrosine residues, recapitulating some of the events that take place during GM-CSF signaling in myeloid cells. We conclude that coexpression of the alpha and beta subunits of hGMR in established murine fibroblasts is sufficient to reconstitute a functional receptor, which is capable of causing ligand-dependent transformation. The oncogenic potential of hGMR lends support to the hypothesis that its deregulated or abnormal expression may play a role in leukemogenesis.     

Considerations for Comprehensive Assessment of Genetic Predisposition in Familial Breast Cancer

About 10–15% of breast cancer cases are family related, classified as familial breast cancer. The disease was first reported in 1866 and determined to be an autosomal dominant genetic disease in 1971. Germline mutations in BRCA1 were discovered and deemed as the first genetic predisposition for the disease in 1994. By now, genetic predispositions for about 40% of familial breast cancer families have been identified. New molecular genetic approaches currently under development should accelerate the process to identify the full spectrum of genetic predispositions for the disease, thereby enabling a better understanding of the genetic basis of the disease and therein providing benefit to high‐risk patients.     

The effects of exercise type and elbow angle on vertical ground reaction force and muscle activity during a push-up plus exercise

Background

Proper alignment of the scapula during upper extremity motion is important in maintaining shoulder joint function and health. Push-up plus exercise is considered as one of the best exercise to strengthen the muscles that stabilize the scapula. The purpose of the study is to examine the effects of push-up plus variants and elbow position on vertical ground reaction force and electromyographical activity of four shoulder muscles during concentric contraction.

Methods

A total of 22 healthy subjects volunteered for the study. Each of the subjects performed both modified and traditional push-up plus. Modified push-up plus was performed with both knees and hands touching the ground while the traditional push-up plus was executed with hands and feet contacting the ground. Electromyography (EMG) of the upper trapezius (UT), lower trapezius (LT), infraspinatus (INFRA), and serratus anterior (SA), and vertical ground reaction forces (vGRF) were collected.

Results

The traditional push-up plus exhibited higher EMG activity in all muscles tested (P < .05) and vertical ground reaction force (P < .001) compared to modified push-up plus. The highest difference in EMG activity between the two exercises was observed with the Serratus Anterior muscle (22%). Additionally, the traditional push-up plus presented a higher vGRF compared to the modified push-up plus (P < .001) by 17%. The SA had the greatest EMG activity compared to the other muscles tested during the concentric phase of the traditional push-up plus, and this did not occur during the plus phase of the exercise.

Conclusion

The highest activity of the serratus anterior occurred at 55° of elbow extension during the concentric phase of the traditional PUP and not at the plus phase of the exercise. This suggests that when prescribing an exercise to target the serratus anterior, a traditional push-up is adequate and the plus-phase is not necessary. However, for patients that cannot perform a traditional push-up, the modified push-up plus would be a great alternative to strengthen their serratus anterior.     

慢性疼痛患者生活质量及其相关因素分析

目的:了解慢性疼痛患者的生活质量状况,并分析其相关影响因素。方法:选取就诊于解放军总医院疼痛科门诊慢性疼痛患者为研究对象,研究工具包括一般资料调查表、简式Mc Gill疼痛问卷(short-form of Mc Gill pain questionnaire,SF-MPQ)及生活质量指数(quality of life index,QL-Index)。结果:1慢性疼痛患者生活质量总分与SF-MPQ总分、感觉项总分、情感项总分、视觉模拟评分(visual analogue scale,VAS)、现时疼痛强度(present pain intensity,PPI)、感觉项计数、情感项计数均呈显著负相关(r=-0.195~-0.433));2多元线性逐步回归分析模型可解释慢性疼痛患者生活质量指数改变的88.8%,情感项总分、感觉项总分、VAS评分、感觉项计数、情感项计数、PPI评分对患者生活质量改变有影响,尤其以目前疼痛强度评分对患者生活质量的影响最为显著。结论:慢性疼痛患者的生活质量受其疼痛特征的多重影响,患者目前疼痛强度对其生活质量的影响最为显著。