Exposure to Extremely Low Frequency Magnetic Fields Has No Effect on Growth Rate or Clonogenic Potential of Multipotential Haemopoietic Progenitor Cells

Abstract

Recent reports indicate an increased risk of acute myeloid leukaemia in children exposed to extremely low frequency magnetic fields (ELFMFs) emitted by high voltage power lines, suggesting that ELFMFs may act as weak tumour promoters. We have investigated possible interactions of weak ELFMFs with primitive haemopoietic cells in vitro using the multipotential progenitor cell line FDCP-mix(A4). We have determined the proliferative activity and clonogenic potential of cells under both optimal and sub-optimal growth conditions and exposed to either ambient laboratory ELFMFs or three other ELFMF regimes representative of those produced by high voltage power lines: nulled fields, Ca²⁺ion cyclotron resonance conditions at 50 Hz, and vertical 50 Hz fields of 6 μT_RMS. Using exposures of 1, 4, 7 and 21 days, we found no significant alteration of growth rate, cell-cycle state or clonogenic efficiency indicating that neither the proliferation nor self-renewal of multipotential FDCP-mix(A4) cells was perturbed.     

The Influence of Pituitary Adenoma Size on Vision and Visual Outcomes after Trans-Sphenoidal Adenectomy: A Report of 78 Cases

Objective

The aims of this study were to investigate the quantitative relationship between pituitary macroadenoma size and degree of visual impairment, and assess visual improvement after surgical resection of the tumor.

Methods

The medical records of patients with pituitary adenoma, who had undergone trans-sphenoidal adenectomy between January 2009 and January 2011, were reviewed. Patients underwent an ocular examination and brain MRI before and after surgery. The visual impairment score (VIS) was derived by combining the scores of best-corrected visual acuity and visual field. The relationship between VIS and tumor size/tumor type/position of the optic chiasm was assessed.

Results

Seventy-eight patients were included (41 male, 37 female). Thirty-two (41%) patients experienced blurred vision or visual field defect as an initial symptom. Receiver operating characteristic curve analysis showed that tumors <2.2 cm tended to cause minimal or no visual impairment. Statistical analysis showed that 1) poor preoperative vision is related to tumor size, displacement of the optic chiasm in the sagittal view on MRI and optic atrophy, and 2) poorer visual prognosis is associated with greater preoperative VIS. In multivariate analysis the only factor significantly related to VIS improvement was increasing pituitary adenoma size, which predicted decreased improvement.

Conclusion

Results from this study show that pituitary adenomas larger than 2 cm cause defects in vision while adenomas 2 cm or smaller do not cause significant visual impairment. Patients with a large macroadenoma or giant adenoma should undergo surgical resection as soon as possible to prevent permanent visual loss.     

胶质母细胞瘤的治疗策略

胶质母细胞瘤（glioblastoma multiforme,GBM）是一种破坏性极强、难以治愈的神经系统肿瘤。临床治疗以手术切除为主,并结合放疗、化疗及电场治疗等多种治疗手段。但GBM侵袭性强、手术难以彻底根除,故患者预后差、死亡率居高不下。因此,延长患者生存时间并提升其生存质量一直是GBM治疗的重要目标。本文将基于GBM治疗策略加以探讨。     

Collective many-body van der Waals interactions in molecular systems

Van der Waals (vdW) interactions are ubiquitous in molecules and condensed matter, and play a crucial role in determining the structure, stability, and function for a wide variety of systems. The accurate prediction of these interactions from first principles is a substantial challenge because they are inherently quantum mechanical phenomena that arise from correlations between many electrons within a given molecular system. We introduce an efficient method that accurately describes the nonadditive many-body vdW energy contributions arising from interactions that cannot be modeled by an effective pairwise approach, and demonstrate that such contributions can significantly exceed the energy of thermal fluctuations-a critical accuracy threshold highly coveted during molecular simulations-in the prediction of several relevant properties. Cases studied include the binding affinity of ellipticine, a DNA-intercalating anticancer agent, the relative energetics between the A- and B-conformations of DNA, and the thermodynamic stability among competing paracetamol molecular crystal polymorphs. Our findings suggest that inclusion of the many-body vdW energy is essential for achieving chemical accuracy and therefore must be accounted for in molecular simulations.     

静磁场对大鼠面颌骨骼肌细胞胞浆内游离钙离子浓度的影响

目的：利用激光共聚焦扫描显微镜（LCSM）技术观察静磁场作用下骨骼肌细胞胞浆内Ca2＋浓度的变化。方法：采用原代培养的大鼠面颌骨骼肌细胞,利用LCSM测定180、280、360mT磁场分别作用12、36、60h后,大鼠面颌骨骼肌细胞内游离Ca2＋浓度的变化。结果：12h组各磁场强度的骨骼肌细胞内游离Ca2＋浓度无明显变化。36h组细胞内Ca2＋浓度均有增加,且随着磁场强度的增加细胞内Ca2＋浓度增加明显。60h组细胞内Ca2＋浓度增加均非常明显,各磁场强度组相互之间无统计学意义。结论：静磁场促使大鼠面颌骨骼肌细胞胞浆内Ca2＋浓度增加,与时间呈正相关关系。