Preparation of Nanoparticles by Solvent Displacement Using a Novel Recirculation System

Submicron colloidal suspensions of poly(ε-caprolactone) (PCL) were prepared by the solvent displacement method, using either the conventional form or a new recirculation device. In the latter case, a process that allows the recirculation of the aqueous phase into a device, providing a continuous flow, is proposed. The influence of the organic solution injection rate and polymer concentration on mean particle size and process yield were studied for both methods. The recirculation rate was also analyzed for the recirculation system. Nanoparticles (NPs) showed mean sizes that ranged from 156 to 381. The smallest particles were obtained when recirculation rate, injection rate and polymer concentration were maximized but at the expense of the yield. The only acceptable yields (83–96%) were obtained at the lowest PCL concentration (2.5% w/v). ANOVA tests (α = 0.05) showed that the variables implicated in the recirculation system significantly affected the mean particle size and the process yield. The entrapment efficiencies of NPs prepared by the conventional method were not significantly different (α = 0.05) from those obtained by the recirculation system.     

CHANGING FOOD PRODUCTION STRATEGIES AMONG GARHWALI RESETTLERS IN THE HIMALAYAS

This article discusses the changing systems of food production among Garhwali resettlers who were forcibly displaced due to the construction of the Tehri Dam in North India. Resettling to a drastically new environment affected their traditional food production strategies and rendered them vulnerable to the vagaries of transition, including the forced adaptation to new cash crop-based farming systems, restricted hunting and fishing areas, and limited access to dairy products. These changes led to an inadequate supply of food and nutrients, especially protein, for these resettlers. Using ethnographic methods, this study illustrates that resettling an agrarian community to a new ecological area significantly changes their food production practices in ways that leave them vulnerable to the potential risk of an impoverished diet.     

Prognostic Implications of Mitral Annular Plane Systolic Excursion in Patients with Hypertension and a Clinical Indication for Cardiac Magnetic Resonance Imaging: A Multicenter Study

ObjectivesThis study sought to evaluate the prognostic value of cardiac magnetic resonance (CMR)-derived mitral annular plane systolic excursion (MAPSE) in a large multicenter population of patients with hypertension.BackgroundIn patients with hypertension, cardiac abnormalities are powerful predictors of adverse outcomes. Long-axis mitral annular movement plays a fundamental role in cardiac mechanics and is an early marker for a number of pathological processes. Given the adverse consequences of cardiac involvement in hypertension, the authors hypothesized that lateral MAPSE may provide incremental prognostic information in these patients.MethodsConsecutive patients with hypertension and a clinical indication for CMR at 4 U.S. medical centers were included in this study (n = 1,735). Lateral MAPSE was measured in the 4-chamber cine view. The primary endpoint was all-cause death. Cox proportional hazards regression modeling was used to examine the association between lateral MAPSE and death. The incremental prognostic value of lateral MAPSE was assessed in nested models.ResultsOver a median follow-up period of 5.1 years, 235 patients died. By Kaplan-Meier analysis, risk of death was significantly higher in patients with a lateral MAPSE < median (10 mm) (log-rank; p < 0.0001). Lateral MAPSE was associated with risk of death after adjustment for clinical and imaging risk factors (hazard ratio [HR]: 1.402-per-millimeter decrease; p < 0.001). Addition of lateral MAPSE in this model resulted in significant improvement in the C-statistic (0.735 to 0.815; p < 0.0001). Continuous net reclassification improvement was 0.739 (95% confidence interval: 0.601 to 0.902). Lateral MAPSE remained significantly associated with death even after adjustment for feature tracking global longitudinal strain (HR: 1.192-per-millimeter decrease; p < 0.001). Lateral MAPSE was independently associated with death among the subgroups of patients with preserved ejection fraction (HR = 1.339; p < 0.001) and in those without history of myocardial infarction (HR: 1.390; p < 0.001).ConclusionsCMR-derived lateral MAPSE is a powerful, independent predictor of mortality in patients with hypertension and a clinical indication for CMR, incremental to common clinical and CMR risk factors. These findings may suggest a role for CMR-derived lateral MAPSE in identifying hypertensive patients at highest risk of death.     

Polyethylene glycol as an alternative polymer solvent for nanoparticle preparation

Solvent toxicity is one of the major drawbacks in the preparation of polymeric nanoparticles today. Here, polyethylene glycols (PEGs) are proposed as non-toxic solvents for the preparation of polymeric nanoparticles. Based on a preparation process similar to the solvent displacement technique, several process parameters were examined for their effects on the properties of the prepared nanoparticles by this method to achieve the optimum preparation conditions. The investigated parameters included polymer type and concentration, volume and temperature of the dispersing phase, methods of dispersing the solvent phase into the non-solvent phase, duration and speed of stirring and washing by dialysis. Ammonio methacrylate copolymer (Eudragit RL), poly-lactide-co-glycolide (PLGA), and PEG-PLGA were found to be successful polymer candidates for the preparation of nanoparticles by this method. Nanoparticles with diameters ranging from 80 to 400 nm can be obtained. The encapsulation efficiencies of bovine serum albumin, and lysozyme as model proteins were ranging from 7.3 ± 2.2% to 69.3 ± 1.8% depending on the strength of polymer–protein interaction. Biological assays confirmed a full lysozyme activity after the preparation process. PEG proved to be a suitable non-toxic solvent for the preparation of polymeric protein-loaded nanoparticles, maintaining the integrity of protein.     

外伤性晶体脱位继发青光眼的手术疗效研究

[目的]探讨外伤性晶体脱位继发青光眼的临床特点以及手术治疗效果。[方法]对本院收治的32例外伤性晶体脱位继发青光眼患者作为研究对象，并对患者采用手术治疗，对患者的临床预后、眼压以及视力恢复情况进行分析。[结果]患者术后视力有明显的改善，术前、术后1周、1个月以及3个月矫正视力分别为（0．082±0．08）、（0．28±0．14）、（0．24±0．39）、（0．32±0．16），各时间点矫正视力比较具有统计学差异（P＜0．05）；患者术前、术后1周、1个月、3个月以及半年眼压分别为（45．83±12．12）mmHg、（17．31±3．43）mmHg、（28．93±4．34）mmHg、（18．25±3．92）mmHg、（17．23±4．34）mmHg，比较发现术后1个月眼压出现升高，但是随访发现眼压得到明显的控制。[结论]对外伤性晶体脱位继发青光眼保守治疗无效情况下采用联合手术治疗，其具有良好的临床效果以及安全性。     

超声乳化联合折叠式人工晶体植入治疗年龄相关性白内障临床观察

目的 探讨年龄相关性白内障患者实施超声乳化术后植入折叠式人工晶体的临床价值.方法 分别选取我院年龄相关性白内障超声乳化术患者植入聚甲基丙烯酸甲酯（PMMA）晶体及折叠式晶体的患者87例和93例.对两组患者术后7 d、14 d以及1个月时的视力进行统计和比较;对两组患者手术前及手术后7 d和1个月时的角膜散光情况进行统计和比较.结果 B组患者在术后7 d、14 d、1个月时视力＞0.8者分别占11.83%、18.28%以及19.35%,均明显优于A组3.45%、5.575%和13.79%,两组比较差异有统计学意义（P＜0.05）.术后7 d两组患者角膜散光分别为（1.20±0.18）D和（0.95±0.21）D,均较术前明显增加,差异有统计学意义（P＜0.05）.术后1个月,A组患者角膜散光为（0.98±0.29）D,仍明显大于术前,差异有统计学意义（P＜0.05）,而B组患者角膜散光为（0.75±0.33）D,与术前相比差别不大,无统计学意义（P＞0.05）.结论 折叠晶体的应用有利于超声乳化术联合人工晶体植入术患者术后视力的提高,如经济状况允许,建议患者选用.     

致白内障基因Hsf4b K65R位点突变对下游热休克蛋白表达的影响

目的:探讨致白内障基因热休克因子4b(Hsf4b)K65R位点突变对其调控下游热休克蛋白(HSP)表达的影响。方法:采用KOD-Plus-Mutagenesis-Kit试剂盒构建pWZL-blast-HA-Hsf4b/K65R赖氨酸突变质粒;通过慢病毒感染小鼠晶状体上皮细胞mLEC构建稳定表达Hsf4b/K65R突变质粒的细胞株;Western blotting检测Hsf4b在mLEC K65R点突变细胞株和野生株中的表达;Western blotting及real-time PCR检测K65R点突变后下游蛋白Hsp70、Hsp90、Hsp27和CryAB表达的变化。结果:阳性克隆PCR及基因测序证明慢病毒载体pWZL-blast-HAHsf4b/K65R构建成功。K65R点突变后不影响Hsf4b在小鼠晶状体上皮细胞mLEC中的表达,但能影响下游蛋白CryAB、Hsp27、Hsp70i和Hsp90a的表达。结论:pWZL-blast-HA-Hsf4b/K65R载体可用于慢病毒感染稳定细胞株构建。Hsf4b K65R位点突变能显著影响其对热休克蛋白的调控功能。