准分子激光原位角膜磨镶术对角膜内皮细胞的影响

目的评价准分子激光原位角膜磨镶术(LASIK)对角膜内皮细胞影响。方法对36例(67只眼)术前屈光度数为-2.00～-14.50D,平均(-7.21±2.96)D近视患者行LASIK治疗,按切削后角膜基质的厚度分为两组:A组250～300μm,B组>300μm,各组患者于术前和术后1周及3、12个月进行角膜内皮镜的检查,观察角膜内皮细胞形态和内皮细胞密度。结果LASIK术前和术后1周及3、12个月角膜内皮细胞形态无明显改变,术前和术后1周及3、12个月角膜内皮细胞密度无显著性差异(P>0.05)。结论LASIK不引起中央部角膜内皮细胞密度和形态的改变,是矫正近视的一种安全有效的屈光手术。     

准分子激光屈光性角膜切削术中应用丝裂霉素疗效Meta分析

目的：探讨准分子激光屈光性角膜切削（PRK）术中使用丝裂霉素（MMC）对抑制角膜上皮下雾状混浊（Haze）的效果及其对角膜内皮细胞的影响。方法：全面检索1981年1月～2010年6月公开发表的关于PRK术中使用0.02%MMC对抑制Haze效果的随机对照试验,对术后Haze发生比例及角膜内皮细胞密度减少量进行Meta分析。结果：共纳入7篇文献,Meta分析结果显示,MMC组比对照组明显地减少了Haze的形成,差异有统计学意义（P〈0.000 01）。与对照组相比,MMC组对角膜内皮细胞密度影响差异无统计学意义（P=0.36）。结论：PRK术中使用0.02%MMC可以明显减少术后Haze的形成,对角膜内皮细胞暂未发现有显著影响。     

夜戴型角膜塑形镜对角膜形态及视觉质量的影响初探

目的探讨夜戴型角膜塑形镜对角膜形态和视觉质量的影响。方法抽取佩戴夜戴型角膜塑形镜的30例轻中度近视青少年为研究对象,对其戴静前后的角膜变化进行评价。结果佩戴前后,其内皮细胞密度比较差异无统计学意义、角度厚度比较差异具有统计学意义(P<0.05);佩戴后裸眼视力和矫正视力均优于佩戴前,差异具有统计学意义(P<0.05)。结论青少年轻中度近视者可通过佩戴夜戴型角膜塑形镜,降低角膜中央区曲率,改变角膜中央的厚度,提高第二天的裸眼视力,同时对角膜内皮细胞无明显影响,是值得推广和使用的一项技术。     

准分子激光屈光性角膜切削术后激素性高眼压

准分子激光屈光性角膜切削术(photogractivekeratectomy,PRK)治疗近视眼的安全性、可靠性和可预测性已被很多临床报告证实,可以认为是摘掉眼镜的有效方法。PRK术后的主要并发症是角膜上皮下混浊(haze)、近视回退和激素性高眼压。本文就100例(187只眼)PRK术后滴用激素而引起糖皮质醇性高眼压进行了观察和分析。     

飞秒激光微小切口角膜基质透镜取出术对角膜内皮细胞的影响

目的探讨飞秒激光微小切口角膜基质透镜取出术(small incision lenticule extraction,SMILE)对术后患者角膜内皮细胞的影响。方法自愿接受SMILE且常规术前检查确认为适应证的患者,共100例(200眼),分别于术前和术后1、3、6个月进行角膜内皮检查,观察并统计分析术后角膜内皮细胞密度、变异系数、六角形细胞百分比、平均细胞面积的变化。结果所有患者手术顺利,无术中术后并发症。术后各时间点与手术前角膜内皮细胞密度、变异系数、六角形细胞百分比、平均角膜细胞面积变化均无统计学差异(P>0.05)。结论 SMILE手术对术后0.5年角膜内皮细胞变化无影响,远期是否有影响有待进一步观察。     

准分子激光原位角膜磨镶术后角膜后表面形态变化

目的观察近视眼准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)后角膜后表面形态变化。方法将151例(288眼)近视患者按近视程度分为低度近视组、中度近视组和高度近视组,采用眼前节全景仪分别于术前,术后1、3、6个月检测各组角膜后表面屈光力和角膜后表面高度,并进行动态对比分析。结果低、中度近视组术后各时间段的角膜后表面屈光力及后表面高度与术前比较无明显改变(P>0.05);而在高度近视组,术后1、3个月角膜后表面屈光力比术前均有增加(P<0.05),术后6个月角膜后表面屈光力与术前比较无明显变化;术后各时间段角膜后表面高度均较术前增加(P<0.05)。结论 LASIK手术可改变高度近视患者的角膜后表面屈光力及后表面高度,眼前节全景仪对于高度近视LASIK术后疗效观察评估具有重要意义。     

准分子激光角膜切削术治疗放射状角膜切开术后残余近视散光

为评价准分子激光屈光性角膜切削术(PRK)治疗放射状角膜切开术(RYO后残余近视散光的预测性、稳定性和安全性，对16例(32眼)RK后残余近视散光患行再次PRK治疗，并连续随访6个月以上。结果表明术后6个月球镜屈光度-0．42±0．62D．柱镜屈光度-0.57±0．52D，裸眼视力≥1．024眼(75%），最佳矫正视力下降l行以上3眼(9.4%)，实际球镜矫正度与预期矫正度相差1．0D以内31眼(96．9%)，柱镜相差1．0D以内26眼(81．25%)。结论：PRK治疗RK术后残余近视散光的预测性强，特别在矫正残余散光方面，其结果令人满意。在最佳矫正视力下降1行以上较常规PRK治疗组有所增加，提示安全性降低。     

准分子激光屈光性角膜术与立体视觉关系的应用性研究

目的探讨准分子激光近视性角膜屈光手术 (PRK、Lasik)后立体视觉的变化 ,从视觉最高级的角度评价准分子激光近视性角膜屈光手术的临床应用价值。方法按就诊先后顺序对符合条件者用颜—郑氏随机点《立体视觉检查图》对接受准分子激光扫描的 30 9例近视患者的术前裸眼、戴镜和术后 3月的立体视觉进行检测。结果近视患者经准分子激光近视性角膜屈光手术后立体视觉变化明显 (P <0 0 1 ) ,尤其伴屈光参差 (屈光度≥ 2 0 0D)者立体视觉增加非常明显 (P <0 0 1 ) ,而Lasik与PRK组相比、5 5mm扫描光光区与 6 0mm光区相比 ,对立体视觉的改善均无明显区别。结论准分子激光屈光性角膜手术 (PRK ,Lasik)在矫正近视的同时 ,能改善和促进立体视功能的形成 ,而立体视觉的改善与激光扫描的方式和直径无关     

激光虹膜周边切除术对角膜内皮功能的影响

目的 探讨激光虹膜周边切除术对青光眼患者角膜内皮功能的影响。方法 采用Topcon SP-2000P型电脑角膜内皮显微镜对63例（81跟）青光服患者进行激光术前、术后1d、1周及1个月的角膜厚度（CT）和角膜内皮细胞密度（ECD）及形态观察。结果 角膜内皮细胞形态无显著性改变。角膜厚度及角膜内皮细胞密度亦无显著性改变。结论 激光虹膜周边切除术对角膜内皮细胞无损伤,不会造成角膜中央部内皮细胞形态改变和密度降低。激光虹膜周边切除术对青光眼是一种简便而有效的治疗手段,是安全可靠的。     

不同角膜曲率近视青少年配戴角膜塑形镜疗效对比

目的 对比不同角膜曲率患者配戴角膜塑形镜控制近视,延缓眼轴增长的疗效。方法 采用回顾性病例分组对比研究方法,选取2017年1月到2020年12月于我院配戴角膜塑形镜2年的102例(204眼)青少年近视患者。按平坦角膜曲率分为平角膜曲率组和陡角膜曲率组两组,分别对戴镜前和戴镜2年后停戴1个月的等效球镜度、眼轴、角膜中央厚度、角膜内皮细胞计数进行测定。结果 配戴治疗2年后比较,平角膜曲率组较陡角膜曲率组的等效球镜度和眼轴均明显增加(P<0.05)。两组的角膜中央厚度和角膜内皮细胞计数分别比较,差异均无统计学意义(P>0.05)。结论 陡角膜曲率患者配戴角膜塑形镜控制近视和眼轴增长的疗效优于平角膜曲率患者,而角膜中央厚度和角膜内皮细胞计数变化无明显差异。及时配戴角膜塑形镜可有效控制近视和眼轴增长,避免高度近视引起眼底并发症。     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.