Impact of static magnetic fields on human myoblast cell cultures

Treatment of skeletal muscle loss due to trauma or tumor ablation therapy still lacks a suitable clinical approach. Creation of functional muscle tissue in vitro using the differentiation potential of human satellite cells (myoblasts) is a promising new research field called tissue engineering. Strong differentiation stimuli, which can induce formation of myofibers after cell expansion, have to be identified and evaluated in order to create sufficient amounts of neo-tissue. The objective of this study was to determine the influence of static magnetic fields (SMF) on human satellite cell cultures as one of the preferred stem cell sources in skeletal muscle tissue engineering. Experiments were performed using human satellite cells with and without SMF stimulation after incubation with a culture medium containing low [differentiation medium (DM)] or high [growth medium (GM)] concentrations of growth factors. Proliferation analysis using the alamarBlue assay revealed no significant influence of SMF on cell division. Real-time RT-PCR of the following marker genes was investigated: myogenic factor 5 (MYF5), myogenic differentiation antigen 1 (MYOD1), myogenin (MYOG), skeletal muscle α1 actin (ACTA1), and embryonic (MYH3), perinatal (MYH8) and adult (MYH1) skeletal muscle myosin heavy chain. We detected an influence on marker gene expression by SMF in terms of a down-regulation of the marker genes in cell cultures treated with SMF and DM, but not in cell cultures treated with SMF and GM. Immunocytochemical investigations using antibodies directed against the differentiation markers confirmed the gene expression results and showed an enhancement of maturation after stimulation with GM and SMF. Additional calculation of the fusion index also revealed an increase in myotube formation in cell cultures treated with SMF and GM. Our findings show that the effect of SMF on the process of differentiation depends on the growth factor concentration in the culture medium in human satellite cultures. SMF alone enhances the maturation of human satellite cells treated with GM, but not satellite cells that were additionally stimulated with serum cessation. Therefore, further investigations are necessary before consideration of SMF for skeletal muscle tissue engineering approaches.     

电针预处理内关穴对心肌缺血再灌注大鼠自噬调控基因和自噬微管相关蛋白轻链3表达的影响

目的:基于不同时间点对比电针预处理内关穴对心肌缺血再灌注(MIRI)模型大鼠自噬基因的不同表达影响,探讨电针预处理的最优时间点。方法:48只SD大鼠随机分为空白组、假手术组、模型组、内关组,每组12只。根据不同时间点按3、7 d分时间点观察,每组6只。采用大鼠冠状动脉左前降支穿线结扎的手段创建心肌缺血再灌注损伤模型。HE染色法检测心肌细胞病理形态学变化,RT-PCR法、Western blotting法检测自噬相关基因在心肌细胞中的表达。结果:第3天模型组心肌损伤程度高于空白组、假手术组,模型组自噬调控基因(Beclin-1)、自噬微管相关蛋白轻链3(LC3-Ⅱ/LC3-Ⅰ)蛋白表达高于空白组、假手术组,差异有统计学意义(均P<0.01)。第3天内关组心肌细胞损伤程度低于模型组,内关组自噬相关基因表达量低于模型组,差异有统计学意义(均P<0.05)。第7天空白组、模型组均存在心肌组织细胞紊乱、结构模糊、自噬泡存在等表现; 模型组自噬相关蛋白表达量明显升高。第7天内关组自噬相关蛋白表达量低于模型组,差异有统计学意义(P<0.05),且心肌损伤情况较第3天改善。第7天模型组、内关组的心肌损害程度均较第3天减轻,细胞器损坏程度也有所改善。第7天模型组、内关组的蛋白表达低于第3天,差异有统计学意义(均P<0.05)。结论:电针预处理内关穴对MIRI模型大鼠的保护机制可能与自噬的相关调节有关,对比不同时间效应差异,第7天效果更佳。     

Rhinophyma: diagnosis and treatment options for a disfiguring tumor of the nose

Rhinophyma is a benign dermatologic disease of the nose affecting primarily Caucasian men in their fifth to seventh decades of life. It is characterized by a slowly progressive enlargement with irregular thickening of the nasal skin and nodular deformation. It is assumed to be the end stage of chronic acne rosacea. Main reasons that urge the patients to seek help are plastic cosmetic and functional impairments such as nasal obstruction. Surgical removal of the hyperplastic tumor mass is the treatment of choice for rhinophyma. In a retrospective review, the authors describe the pros and cons of the main treatment modalities that have been described in literature and present their own clinical experience.     

Thio-dimethylarsinate is a common metabolite in urine samples from arsenic-exposed women in Bangladesh

Over the last 6 years, much work on arsenic species in urine samples has been directed toward the determination of the reduced dimethylated arsenic species, DMA(III), because of its high toxicity and perceived key role in the metabolism of inorganic arsenic. Recent work, however, has suggested that DMA(III) may at times have been misidentified because its chromatographic properties can be similar to those of thio-dimethylarsinate (thio-DMA). We analyzed by HPLC-ICPMS (inductively coupled plasma mass spectrometry) urine samples from 75 arsenic-exposed women from Bangladesh with total arsenic concentrations ranging from 8 to 1034 microg As/L and found that thio-DMA was present in 44% of the samples at concentrations ranging mostly from trace amounts to 24 microg As/L (one sample contained 123 microg As/L). Cytotoxicity testing with HepG2 cells derived from human hepatocarcinoma indicated that thio-DMA was about 10-fold more cytotoxic than dimethylarsinate (DMA). The widespread occurrence of thio-DMA in urine from these arsenic-exposed women suggests that this arsenical may also be present in other urine samples and has so far escaped detection. The work highlights the need for analytical methods providing specific determinations of arsenic compounds in future studies on arsenic metabolism and toxicology.     

Susceptibility induced gray-white matter MRI contrast in the human brain

MR phase images have shown significantly improved contrast between cortical gray and white matter regions compared to magnitude images obtained with gradient echo sequences. A variety of underlying biophysical mechanisms (including iron, blood, myelin content, macromolecular chemical exchange, and fiber orientation) have been suggested to account for this observation but assessing the individual contribution of these factors is limited in vivo.For a closer investigation of iron and myelin induced susceptibility changes, postmortem MRI of six human corpses (age range at death: 56-80 years) was acquired in situ. Following autopsy, the iron concentrations in the frontal and occipital cortex as well as in white matter regions were chemically determined. The magnetization transfer ratio (MTR) was used as an indirect measure for myelin content. Susceptibility effects were assessed separately by determining R2* relaxation rates and quantitative phase shifts. Contributions of myelin and iron to local variations of the susceptibility were assessed by univariate and multivariate linear regression analysis.Mean iron concentration was lower in the frontal cortex than in frontal white matter (26 ± 6 vs. 45 ± 6 mg/kg wet tissue) while an inverse relation was found in the occipital lobe (cortical gray matter: 41 ± 10 vs. white matter: 34 ± 10 mg/kg wet tissue). Multiple regression analysis revealed iron and MTR as independent predictors of the effective transverse relaxation rate R2* but solely MTR was identified as source of MR phase contrast. R2* was correlated with iron concentrations in cortical gray matter only (r = 0.42, p < 0.05).In conclusion, MR phase contrast between cortical gray and white matter can be mainly attributed to variations in myelin content, but not to iron concentration. Both, myelin and iron impact the effective transverse relaxation rate R2* significantly. Magnitude contrast is limited because it only reflects the extent but not the direction of the susceptibility shift.     

Angiotensin converting enzyme 2 polymorphisms and postexercise hypotension in hypertensive medicated individuals

The renin‐angiotensin aldosterone system (RAAS) is associated with diverse physiological responses and adaptations to exercise. The angiotensin converting enzyme (ACE) 2 has vasodilatory effects, which might be associated with the blood pressure (BP) responses to acute exercise. The aim of this study was to investigate the role of ACE2 polymorphisms in postexercise hypotension (PEH). Thirty‐four medicated hypertensive (61·3 ± 1·7 years, 76·1 ± 2·7 kg, 160 ± 1·6 cm) men (n = 12) and women (n = 22), participated in a control and a moderate intensity exercise session in a randomized order. After both experimental sessions, they left the laboratory wearing an ambulatory BP device for 24‐h monitoring. ACE2 polymorphisms (Int‐1 and Int‐3) were assessed by polymerase chain reaction. Over the course of 5‐h monitoring, we observed a significant reduction in SBP and DBP following exercise in the AA/AG of the Int‐1 polymorphism (p‐interaction = 0·02 and 0·001, respectively), whereas this could not be found in the individuals homozygous G (p‐interaction = 0·76 and 0·51, respectively). With regard to Int‐3 polymorphism, individuals AA/AG showed a significant reduction in SBP following exercise (p‐interaction <0·0001) but not for DBP (p‐interaction = 0·06) whereas GG individuals showed only a significant reduction in DBP following exercise (p‐interaction = 0·02). Our results suggest that ACE2 polymorphism could affect PEH; however, larger trials are needed to confirm our findings.     

Lifetime exposure to arsenic in residential drinking water in Central Europe

Objective

Methods and results are presented for an arsenic exposure assessment integral to an epidemiological case–control study of arsenic and cancer—the European Commission funded ASHRAM (Arsenic Health Risk Assessment and Molecular Epidemiology) study carried out in some counties of Hungary, Romania and Slovakia.

Methods

The exposure history of each participant (N = 1,392) was constructed by taking into account how much water they consumed (as water, in drinks and in food), sources of drinking water in their various residences over their lifetime, and the concentrations of arsenic in their various water supplies measured by Hydride Generation-Atomic Absorption Spectrometry (HG-AAS). Concentrations of arsenic in previous water supplies were either derived from contemporary analyses of the same source, or from routine historical data from measurements performed by the authorities in each country. Using this approach, 80% of the recorded lifetime residential history was matched to an arsenic concentration. Seven indices of current, life time, and peak exposure were calculated.

Results

The exposure indices were all log-normally distributed and the mean and median lifetime average concentrations were in Hungary 14.7 and 13.3 μg l^?1, Romania 3.8 and 0.7 μg l^?1 and in Slovakia 1.9 and 0.8 μg l^?1, respectively. Overall 25% of the population had average concentrations over 10 μg l^?1 and 8% with exposure over 50 μg l^?1.

Conclusions

Careful assessment of arsenic in drinking water supplies (both current and previous) enabled the majority of study participants’ cumulative lifetime of potential exposure to arsenic in residential water to be characterised.