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Arsenic, a naturally occurring metal-like chemical element, is one of the 10 chemicals of major public concerns listed by the World Health Organization as harmful to the environment and human health. It can enter the human body through breathing, intaking food, drinking water, skin exposure, and other ways, and long-term exposure to arsenic can cause cancer of multiple organs and impaired function of multiple systems. Epigenetic mechanisms play an important role in arsenic-induced health effects, and research suggested that the carcinogenicity of arsenic may be associated with epigenetic changes. Previous studies focused on the effects of arsenic on DNA methylation modification. In recent years, research showed that 5-hydroxymethylcytosine (5-hmC), an intermediate of active demethylation of DNA, can act as a sensitive epigenetic mark and play a crucial role as a "bridge" between arsenic exposure and health effects. Based on the latest research progress on the role of DNA hydroxymethylation in the health effects associated with arsenic exposure, this article briefly described the relationship between the health effects of arsenic exposure and DNA hydroxymethylation, summarized the possible mechanisms of DNA hydroxymethylation in the health effects associated with arsenic exposure, and provided a scientific basis for preventing and treating the health effects associated with arsenic exposure.
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Objective To investigate the application value of low kilovolt technique combined with lower contrast in the head and neck angiography by the second-generation dual source CT.Methods From October 2013 to January 2015,120 patients undergoing head and neck computed tomography angiography (CTA) were randomly divided into groups A,B,C,D.Each group was given a different tube current and different dose of contrast agent and saline solution 50 ml.Group A received current 100 mA and contrast agent 50 ml,group B received current 100 mA and contrast agent 40 ml,group C received current 80 mA and contrast agent 50 ml,and group D received current 80 mA and contrast agent 40 ml.CT values of aortic arch,bilateral common carotid artery bifurcation,double sided M1 segment of middle cerebral artery,basilar artery enhanced degree of the straight sinus were measured in each group.Residual artifacts caused by contrast agent in brachiocephalic vein and subclavian vein were observed.5-score method was used to assess the quality of reconstructed image,and the radiation exposure dose was calculated.Results The mean effective dose was reduced by 29％ in group C as compared with group A [(0.53±0.17) mGy vs.(0.74±0.04) mGy].There was no significant difference in developing strength in cerebral arteries angiography between group C and group A (P=0.247),but the inage noise was slightly larger in group C than group A,without significant differences (P=0.203).The average effective dose in group A was almost the same as that in group B [(0.74 ± 0.04) mGy vs.(0.73 ± 0.05) mGy].Structure display of cerebral arteries on CT volume rendering (VR) and multiplane reformation (MPR) images had no significant differences between group A and group B (P=0.114).The average effective dose in group C was almost the same as that in group D[(0.53 ± 0.17) mGy vs.(0.53 ±0.01) mGy].Structure display of cerebral arteries on CT volume rendering (VR) and muhiplane reformation (MPR) images had no significant differences between group C and group D (P=0.109).The mean effective dose was reduced by 28％ in group D as compared with group B[(0.53±0.01)mGy vs.(0.73±0.05) mGy].There was no significant difference in developing strength in cerebral arteries angiography between group C and group A (P=0.236),but the image noise was sligbtly larger in group C than group A (P =0.212).Conclusions Application of low tube current combined with low concentration of contrast agent in the head and neck dual-source CT angiography is feasible in clinical diagnosis,with good clinical value.It can not only get better image quality,but also meet the needs of clinical diagnosis.
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Objective:To summarize the clinicopathologia and imaging features of Hemiballism-hemichorea induced by hyperglycemia and increase the understanding of the disease and improve the accuracy of diagnosis. Methods:The imaging images and clinical manifestation of 5 cases Hemiballism-hemichorea induced by hyperglycemia were analyzed retrospectively. The disease pathogenesis and mechanism relating to the Characteristic neuroradiological findings was obtained by literature review. Results:The common clinical manifestation of Hemiballism-hemichorea induced by hyperglycemia is unilateral limb involuntary movements. CT scans typically show an area of hyperdensity in the basal ganglia and The characteristic finding on the T1-weighted MRI is high signal intensity in the contralateral putamen. Conclusion: Hemiballism-hemichorea induced by hyperglycemia is an unusual but important differential diagnosis in patients with particular neuroradiological findings as prompt diagnosis and treatment of hyperglycemia has an excellent prognosis. The correct diagnosis could be received through integrated the patient's past medical history, presentation, laboratory and imaging inspection into account.