Which mesh for hernia repair?

INTRODUCTION

The concept of using a mesh to repair hernias was introduced over 50 years ago. Mesh repair is now standard in most countries and widely accepted as superior to primary suture repair. As a result, there has been a rapid growth in the variety of meshes available and choosing the appropriate one can be difficult. This article outlines the general properties of meshes and factors to be considered when selecting one.

MATERIALS AND METHODS

We performed a search of the medical literature from 1950 to 1 May 2009, as indexed by Medline, using the PubMed search engine (<http://www.pubmed.gov>). To capture all potentially relevant articles with the highest degree of sensitivity, the search terms were intentionally broad. We used the following terms: ‘mesh, pore size, strength, recurrence, complications, lightweight, properties’. We also hand-searched the bibliographies of relevant articles and product literature to identify additional pertinent reports.

RESULTS AND CONCLUSIONS

The most important properties of meshes were found to be the type of filament, tensile strength and porosity. These determine the weight of the mesh and its biocompatibility. The tensile strength required is much less than originally presumed and light-weight meshes are thought to be superior due to their increased flexibility and reduction in discomfort. Large pores are also associated with a reduced risk of infection and shrinkage. For meshes placed in the peritoneal cavity, consideration should also be given to the risk of adhesion formation. A variety of composite meshes have been promoted to address this, but none appears superior to the others. Finally, biomaterials such as acellular dermis have a place for use in infected fields but have yet to prove their worth in routine hernia repair.     

单侧睁眼闭眼引起的全脑脑电图差异研究

目的脑电图(electroencephalogram,EEG)是通过脑电描记仪将脑自身微弱的生物电放大记录成为一种脑电谱图,以帮助诊断疾病的一种现代辅助检查方法。早期对闭眼和睁眼差异的研究结果多集中在位于枕叶-顶叶的α波的幅度的变化,闭眼幅度大于睁眼。本文主要探讨单侧眼睛(左眼和右眼)分别睁开和闭合时所引起的七波段脑电图谱:Delta(0.5～3.5 Hz),Theta(4～7Hz),Alpha-1(7.5～9.5 Hz),Alpha-2(10～12 Hz),Beta-1(13～23 Hz),Beta-2(24～34 Hz)and Gamma(35～45 Hz)的差异。方法受试者为15名健康男性(年龄19～27岁),静息状态下,在安静舒适的室内环境中,将随机单侧睁眼闭眼(左开/左闭,右开/右闭)作为刺激,采用电脑自动记录七波段脑电图(128-导EEG)。结果静息状态下的脑电区域能量:中间频率波段alpha-1与alpha-2闭眼时明显高于睁眼时(alpha-1,P=0.038;alpha-2,P=0.02),而比较单侧睁眼闭眼alpha-1与alpha-2时,差异无统计学意义(alpha-1,P=0.502;alpha-2,P=0.984),其他波段差异无统计学意义。结论闭眼情况下α波功率显著高于睁眼,而在比较七波段单侧眼睛睁闭时,差异无统计学意义,说明单侧外界光线刺激引起的对侧大脑半球及视觉皮质的变化,经过视交叉传入,胼胝体整合两边的头脑反应是一种持续性变化(2 min),从而使两侧EEG区域能量图一致。     

Efficacy of 3,5-dibromo-L-phenylalanine in rat models of stroke,seizures and sensorimotor gating deficit

Background and purpose:

Abnormal glutamatergic activity is implicated in neurologic and neuropsychiatric disorders. Selective glutamate receptor antagonists were highly effective in animal models of stroke and seizures but failed in further clinical development because of serious side effects, including an almost complete set of symptoms of schizophrenia. Therefore, the novel polyvalent glutamatergic agent 3,5-dibromo-L-phenylalanine (3,5-DBr-L-Phe) was studied in rat models of stroke, seizures and sensorimotor gating deficit.

Experimental approach:

3,5-DBr-L-Phe was administered intraperitoneally as three boluses after intracerebral injection of endothelin-1 (ET-1) adjacent to the middle cerebral artery to cause brain injury (a model of stroke). 3,5-DBr-L-Phe was also given as a single bolus prior to pentylenetetrazole (PTZ) injection to induce seizures or prior to the administration of the N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine (MK-801) to cause disruption of prepulse inhibition (PPI) of startle (sensorimotor gating deficit).

Key results:

Brain damage caused by ET-1 was reduced by 52%, which is comparable with the effects of MK-801 in this model as reported by others. 3,5-DBr-L-Phe significantly reduced seizures induced by PTZ without the significant effects on arterial blood pressure and heart rate normally caused by NMDA antagonists. 3,5-DBr-L-Phe prevented the disruption of PPI measured 3 days after the administration of ET-1. 3,5-DBr-L-Phe also eliminated sensorimotor gating deficit caused by MK-801.

Conclusion and implications:

The pharmacological profile of 3,5-DBr-L-Phe might be beneficial not only for developing a therapy for the neurological and cognitive symptoms of stroke and seizures but also for some neuropsychiatric disorders.