Targeting apoptosis pathways in childhood malignancies

Evasion of apoptosis (programmed cell death) is a characteristic feature of human cancers including childhood malignancies. Since cytotoxic therapies such as chemotherapy or radiotherapy trigger apoptosis as a primary mechanism of action, resistance to apoptosis can also lead to treatment resistance. Studies on apoptosis pathways in childhood malignancies yielded a series of key molecules that can now be exploited as molecular targets for the development of targeted therapies. This strategy is anticipated to open novel perspectives for more effective treatment options for children with cancer.     

频域光学相干断层扫描在眼挫伤黄斑损害中的应用

目的：观察眼挫伤所致黄斑损害的频域光学相干断层扫描（Frequency Domain Optical Coherence Tomo-graphy）图像特征。方法：对34眼眼外伤患者进行FD-OCT扫描检查。两组之间的比较采用t检验进行。结果：外伤眼急性期黄斑区OCT图像主要表现为：神经上皮浆液性脱离、色素上皮脱离、视网膜内出血及黄斑区神经上皮层变薄。回复期黄斑区OCT图像主要表现为黄斑区神经上皮层变薄、黄斑区增生膜形成、黄斑裂孔。结论：眼挫伤黄斑损害的OCT图像可以提供黄斑区解剖结构改变的重要信息,有助于对病变进行诊断及全面评估。     

Rescue of internal scaffold-deleted Mason-Pfizer monkey virus particle production by plasma membrane targeting

The Mason-Pfizer monkey virus (M-PMV) Gag protein follows a morphogenesis pathway in which immature capsids are preassembled within the cytoplasm before interaction with and budding through the plasma membrane. Intracytoplasmic assembly is facilitated by sequences within the p12 domain of Gag that we have termed the Internal Scaffold Domain (ISD). If M-PMV utilizes an ISD then what provides the equivalent function for most other retroviruses that assemble at the plasma membrane? To investigate the possibility that the membrane itself fulfills this role, we have combined functional deletion of the ISD with a mutation that disrupts intracellular targeting or with a plasma membrane targeting signal. By either modification, targeting of ISD-deleted Gag to the plasma membrane restores particle production. These results provide support for a model in which the plasma membrane and the D-type ISD provide an interchangeable scaffold-like function in retrovirus assembly.     

Low frequency and variability of FLT3 mutations in Korean patients with acute myeloid leukemia

FLT3 mutations are common genetic changes, and are reported to have prognostic significance in acute myeloid leukemia (AML). The FLT3 internal tandem duplication (ITD) and the D835 activating mutation in the tyrosine kinase domain (TKD) were analyzed by polymerase chain reaction (PCR) in the genomic DNA of Korean patients with AML at diagnosis and during follow-up. There were 226 patients with AML enrolled between March 1996 and August 2005. The incidence of ITD and TKD at diagnosis was 13% (29/226) and 3% (6/226). When compared to Western and other Asian patients with AML, Korean patients had a lower frequency by about two-thirds of ITD and TKD. Among the non-M3 cases (N=203), the patients with an ITD had a significantly shorter event-free survival when compared with those without an ITD (p=0.0079). Among 54 relapsed patients, 9 patients had the FLT3 ITD at diagnosis. Six patients demonstrated a reappearance of the ITD and 3 patients remained negative at relapse. One patient, among 45 patients who relapsed, had a negative baseline ITD but acquired a de novo ITD at relapse. There were 101 samples from 93 patients in remission; they were all negative for an ITD. Among 34 patients who failed to achieve a remission, five patients had a persistent ITD and one patient had a de novo ITD. These results support the concept of resistance of FLT3 ITD leukemic clones to chemotherapy. Therefore, effective therapy with FLT3 targeting agents may improve the prognosis of non-M3 AML patients with the FLT3 mutation.     

Validation of PNPLA3 polymorphisms as risk factor for NAFLD and liver fibrosis in an admixed population

Introduction and aimStudies have shown that two polymorphisms were associated with steatosis and progression of non-alcoholic fatty liver disease (NAFLD) in different populations: the Patatin-like Phospholipase Domain Containing 3 (PNPLA3) and Transmembrane 6 Superfamily Member 2 (TM6SF2). However, the frequency and significance of these polymorphisms in an admixed population, i.e., Brazilian, is unknown. Therefore, we aimed to evaluate them in healthy subjects in comparison to patients with NAFLD.Material and methodsThis was a multicenter cross-sectional study in 248 patients with biopsy-proven NAFLD and in 134 healthy controls from two tertiary centers in Brazil. PNPLA3 (rs738409 c.444C>G) and TM6SF2 (rs58542926 c.449C>T) polymorphisms were evaluated.ResultsIn controls, the frequencies of PNPLA3 CC and CG + GG were 49.25% and 50.74%, respectively; in NAFLD patients, this was 31.05% and 68.88% (p = 0.0044, 95% CI 1.037–2.977). PNPLA3 GG subjects had an increased risk (3.29-fold) of having NAFLD when compared to CC subjects (p = 0.0044, 95% CI 1.504–7.225). In patients with nonalcoholic steatohepatitis (NASH), PNPLA3 GG compared to CC was associated with higher AST levels [38.4 ± 25.3 versus 36.7 ± 40.1 IU/L, p = 0.0395)] and with the presence of liver fibrosis (≥F2 fibrosis, p = 0.0272). TM6SF2 polymorphisms were not in Hardy-Weinberg equilibrium in our NAFLD group precluding further analysis.ConclusionWe demonstrated for the first time that PNPLA3 CG + GG increase the risk of NAFLD among Brazilian subjects. Moreover, PNPLA3 GG was associated with liver enzyme elevation and fibrosis in NASH patients.     

Ultrasound Assessment of Articular Cartilage: Analysis of the Frequency Profile of Reflected Signals from Naturally and Artificially Degraded Samples

This article investigates in vitro the hypothesis that the frequency profile of ultrasound reflections may be used to characterize degradation and osteoarthritic progression in articular cartilage, irrespective of the effects of transducer orientation. To this end, ultrasound echoes were taken in the time domain from the articular surface and osteochondral junction of normal, collagen meshwork-disrupted, proteoglycan-depleted, and osteoarthritic samples, converted to the frequency domain by fast Fourier transform and analyzed. Our results show the significant effects of specific enzymatic degradation programs on the ultrasound frequency profile of reflections from the cartilage surface and osteochondral junction, and their manifestation in the tissue surrounding a focal osteoarthritic defect. Collagen meshwork disruption was most apparent in the profile of reflections from the articular surface, while proteoglycan depletion was most clearly observed in the reflections from the osteochondral junction. The reflected signals from the osteochondral junction may further contain information about the subchondral bone. From these results we proposed that the analysis of specific frequencies of reflected ultrasound signals has the potential to differentiate normal from degraded articular cartilage-on-bone, when the angle of incidence can be controlled within a ±1.2° limit. This encourages further research into the effects of progressive artificial degradation of the cartilage matrix and subchondral bone on the spectral profile to quantify the relationship between the frequency profile and the level of specific degradation in naturally degraded joints.     

The influence of an unilateral carotid artery stenosis on brain oxygenation

We study the impact of varying degrees of unilateral stenoses of an carotid artery on pulsatile blood flow and oxygen transport from the heart to the brain. For the numerical simulation a model reduction approach is used involving non-linear 1-D transport equation systems, linear 1-D transport equations and 0-D models. The haemodynamic effects of vessels beyond the outflow boundaries of the 1-D models are accounted for using a 0-D lumped three element windkessel model. At the cerebral outflow boundaries the 0-D windkessel model is extended by metabolic autoregulation, based on the cerebral oxygen supply. Additionally lumped parameter models are applied to incorporate the impact of the carotid stenosis. Our model suggests that for a severe unilateral stenosis in the right carotid artery the partial pressure of oxygen in the brain area at risk can only be restored, if the corresponding cerebral resistance is significantly decreased and if the circle of Willis (CoW) is complete.     

护理人员预防术中获得性压力性损伤最佳证据应用障碍的质性研究

目的 深入了解护士应用预防术中获得性压力性损伤最佳证据的障碍因素,为实施压力性损伤干预提供参考。 方法 采用描述性质性研究方法,选取西部地区6所三级甲等医院手术室11名护士为研究对象,基于理论域框架制定访谈提纲,进行半结构式深度访谈,采用定向内容分析法对访谈资料进行分析。 结果 护士应用最佳证据的障碍因素分别为知识（最佳证据相关知识不足）;环境因素（特殊手术体位辅助工具不足、医院信息系统智能性欠佳）;动力和目标（患者及家属对预防压力性损伤的重视度较低,影响手术室护士积极性）;行为规范（工作流程有待完善）;结果的期望（手术室护士对实施最佳证据的效果缺乏信心）。 结论 影响术中获得性压力性损伤最佳证据在临床应用的障碍因素较多,需要科室在明确障碍因素的基础上,推进术中获得性压力性损伤最佳证据的临床应用。     

Mutants of β2-glycoprotein I: Their features and potent applications

β2-Glycoprotein I (β2GPI) is a highly-glycosylated plasma protein composed of five homologous domains which regulates coagulation, fibrinolysis, and/or angiogenesis by interacting to negatively charged hydrophobic molecules and/or with plasminogen and its metabolites. The present study focused on structural and functional characterization of β2GPI's domain I (DI) and V (DV). Through N-terminal amino acid sequencing, a novel plasmin-cleaved site at K²⁸⁷C²⁸⁸ was identified in DV. We further modified the intact DV by altering two amino acids at specific proteolytic cleavage sites to generate three stable DV mutants: DV(PP), (PE), and (AA). Results of both SDS-PAGE and MALDI-TOF-MS showed that all three DV mutants were more stable than the intact DV, and DV(PE) was predominantly resistant to proteolysis. Competitive ELISA assessed affinities of intact β2GPI and those mutants to cardiolipin. In culture system, all DV and DI mutants potently inhibited HUVEC's proliferation by 18–30% as compared to control. Only DI and nicked β2GPI showed significant inhibition in HUVEC's tube formation. Moreover, DV(PE)-coated affinity columns demonstrated its binding property towards anionic lipids and could substantially isolate anionic DOPS from zwitterionic DOPC as a purification model. In summary, the proteolytic resistant and unhindered phospholipid (PL) binding properties of DV(PE) have made it an appealing element for subsequent prospective studies. Future in-depth characterization and optimized applications of cleavage-resistant DV(PE) would complement its full capacity as a novel clinical modality in the field of vascular imaging and/or lipidomics studies.