Melatonin reduces oxidative stress and improves vascular function in pulmonary hypertensive newborn sheep

Pulmonary hypertension of the newborn (PHN) constitutes a critical condition with severe cardiovascular and neurological consequences. One of its main causes is hypoxia during gestation, and thus, it is a public health concern in populations living above 2500 m. Although some mechanisms are recognized, the pathophysiological facts that lead to PHN are not fully understood, which explains the lack of an effective treatment. Oxidative stress is one of the proposed mechanisms inducing pulmonary vascular dysfunction and PHN. Therefore, we assessed whether melatonin, a potent antioxidant, improves pulmonary vascular function. Twelve newborn sheep were gestated, born, and raised at 3600 meters. At 3 days old, lambs were catheterized and daily cardiovascular measurements were recorded. Lambs were divided into two groups, one received daily vehicle as control and another received daily melatonin (1 mg/kg/d), for 8 days. At 11 days old, lung tissue and small pulmonary arteries (SPA) were collected. Melatonin decreased pulmonary pressure and resistance for the first 3 days of treatment. Further, melatonin significantly improved the vasodilator function of SPA, enhancing the endothelial‐ and muscular‐dependent pathways. This was associated with an enhanced nitric oxide‐dependent and nitric oxide independent vasodilator components and with increased nitric oxide bioavailability in lung tissue. Further, melatonin reduced the pulmonary oxidative stress markers and increased enzymatic and nonenzymatic antioxidant capacity. Finally, these effects were associated with an increase of lumen diameter and a mild decrease in the wall of the pulmonary arteries. These outcomes support the use of melatonin as an adjuvant in the treatment for PHN.     

Sliding mode control of time‐varying delay Markov jump with quantized output

This paper investigates the quantized sliding mode control of Markov jump systems with time‐varying delay. A dynamical adjustment law is explored to quantize the system output. By constructing an observer‐based integral sliding surface, a sliding mode controller is designed to take over the dynamical motion of state estimation and ensure the reachability of sliding surface. A new scaling manner is developed to build the bound between the system output and quantized error. With the help of separation strategies for controller synthesis and general transition probabilities and a lower bound theorem for nonlinear integral terms, a new synthesis method to ensure the required stability and meet the required performance is proposed in the form of linear matrix inequalities. The validity of the proposed control method is illustrated by a numerical example.     

MRI图像融合技术在肛瘘评估中的初步应用

目的采用图像融合技术获得T2WI与T2WI-FS的融合图像，评估其在肛瘘及肛周结构显示中的优势。 方法2016年6月至2018年6月，前瞻性选择中山大学附属第一医院29例肛瘘患者进行肛管磁共振（MR）检查，采用图像融合技术获取T2WI与T2WI-FS的融合图像T2WI-Fusion，利用Fisher score算法计算瘘管及肛门括约肌的组织间分辨力Fisher值、脂肪与肛门括约肌间的Fisher值，评估融合图像中瘘管及肛周结构的显示情况。采用改进的双刺激连续质量量表（DSCQS）对T2WI-FS、T2WI、增强3D-VIBE和T2WI-Fusion序列图像进行主观图像质量评价。 结果29例患者均成功获得T2WI与T2WI-FS的融合图像T2WI-Fusion。T2WI-Fusion、T2WI瘘管与括约肌间Fisher均值分别为6.46、3.31，T2WI-Fusion图像对瘘管的显示优于T2WI序列图像（P<0.001）。T2WI-Fusion、T2WI-FS脂肪与括约肌间Fisher均值分别为10.61、2.45，T2WI-Fusion图像对括约肌的显示优于T2WI-FS序列图像（P<0.001）。T2WI-Fusion对瘘管与括约肌的图像质量评价总评分均高于T2WI-FS、T2WI、增强3D-VIBE序列（P<0.001）。 结论MRI图像融合技术同时具备T2WI及T2WI-FS的优势，无需增加扫描序列及扫描时间，且操作简单，花费时间短，显著提高病变及肛周解剖结构的对比度和图像质量。     

玻璃体切割联合内界膜剥除治疗糖尿病性黄斑水肿

评估玻璃体切割联合内界膜剥除对糖尿病性黄斑水肿（DME）的疗效。方法：回顾性病例对照研究。2014年6月至2017年1月间因糖尿病视网膜病变合并玻璃体积血或增殖病变于温州医科大学附属眼视光医院杭州院区行玻璃体切割手术治疗，且术前或术中经光学相干断层扫描（OCT）检查确诊合并DME的患者31例（33眼）纳入研究。16例（18眼）术中联合内界膜剥除作为剥膜组，15例（15眼）仅接受玻璃体切割手术治疗者作为对照组。所有手术均由同一医师主刀完成。术后1、3个月随访时复查OCT，对比观察黄斑中心厚度（CMT）和视力的术后变化情况。随访中CMT和最佳矫正视力（BCVA）比较采用重复测量方差分析，组间CMT和BCVA比较采用独立样本t检验。结果：手术前，手术后1、3个月2组间比较LogMAR视力总体差异有统计学意义（F=15.93，P<0.001）。术后 1个月时剥膜组BCVA高于对照组（t=2.55，P=0.02），但术后3个月时2组间差异无统计学意义（t=0.82， P=0.42）。手术前，手术后1、3个月CMT总体差异无统计学意义（F=2.85，P=0.065）。术后1、3个月时，剥膜组的CMT均低于对照组，2组间差异均有统计学意义（t=2.24，P=0.03；t=3.79，P=0.001）。术后1个月时，剥膜组有效（与术前比CMT减少20%以上）、无效（变化不超过20%）及恶化（增厚超过 20%）的例数分别为8、6、4例，术后3个月时则分别为11、5、2例，与对照组相比，术后1个月时组间差异无统计学意义（Z=-1.687，P=0.092），术后3个月时剥膜组DME改善有效比例明显高于对照组，组间差异有统计学意义（Z=-2.177，P=0.029）。结论：对于非牵拉性DME，内界膜剥除有助于术后早期DME消退。