Mesothelial cells: their structure,function and role in serosal repair

The mesothelium is composed of an extensive monolayer of specialized cells (mesothelial cells) that line the body's serous cavities and internal organs. Traditionally, this layer was thought to be a simple tissue with the sole function of providing a slippery, non-adhesive and protective surface to facilitate intracoelomic movement. However, with the gradual accumulation of information about serosal tissues over the years, the mesothelium is now recognized as a dynamic cellular membrane with many important functions. These include transport and movement of fluid and particulate matter across the serosal cavities, leucocyte migration in response to inflammatory mediators, synthesis of pro-inflammatory cytokines, growth factors and extracellular matrix proteins to aid in serosal repair, release of factors to promote both the deposition and clearance of fibrin, and antigen presentation. Furthermore, the secretion of molecules, such as glycosaminoglycans and lubricants, not only protects tissues from abrasion, but also from infection and possibly tumour dissemination. Mesothelium is also unlike other epithelial-like surfaces because healing appears diffusely across the denuded surface, whereas in true epithelia, healing occurs solely at the wound edges as sheets of cells. Although controversial, recent studies have begun to shed light on the mechanisms involved in mesothelial regeneration. In the present review, the current understanding of the structure and function of the mesothelium and the biology of mesothelial cells is discussed, together with recent insights into the mechanisms regulating its repair.     

氟芬合剂对全身麻醉脊柱手术患者血流动力学的影响

[目的]观察全身麻醉期间氟芬合剂对脊柱手术患者血压及心率的影响.[方法]选择40例需在全身麻醉下施行脊柱手术患者,随机分为观察组和对照组,每组各为20例.观察组患者在手术开始前5 min静脉注射给予氟芬合剂6 mL,对照组给予等量生理盐水,观察手术开始后5,15,30,45 min时患者血压及心率的变化情况.[结果]观察组患者手术开始后血压显著下降,心率逐渐减慢,45 min时血压及心率接近麻醉前水平,与对照组比较,血压与心率变化均有显著性差异.[结论]在麻醉期间氟芬合剂可有效地降低血压,减慢心率,维持时间较长,可防止手术刺激所引起的血压升高及心率增快.     

Ruptured cerebral aneurysms associated with arterial occlusion

Seven cases of ruptured cerebral aneurysm associated with an occlusion of a large cerebral artery are reported. All seven patients had never suffered from ischemic cerebrovascular disease before the aneurysmal rupture. All nine aneurysms, including the two unruptured ones, arose on the artery serving as an important collateral pathway, and eight of the nine were found in locations where saccular aneurysms are known to occur infrequently. The role of hemodynamic factors in the pathogenesis of these aneurysms is stressed.     

Visual phenomena following light coagulation in central serous retinopathy (CSR)

A report on three patients with illustrations of their visual anomalies following light coagulation for their CSR disease is presented. The correspondence of the phenomena illustrated with the ophthalmoscopically visible fundus changes prove their objective origin.     

Physiologic-insensitive left ventricular assist predisposes right-sided circulatory failure: a pilot simulation and validation study

Right-sided circulatory failure (RSCF) is a serious complication in 15-30% of patients receiving a left ventricular assist device (LVAD). It is hypothesized that left ventricular support which lacks physiologic properties predisposes to RSCF. An integral computer simulation and experimental validation protocol was performed. The results suggest that with conventional insensitive left ventricular support right-sided circulatory function is compromised, which may form a substrate for the onset or progress of RSCF. Feedback control of the LVAD could provide a means to counter this problem. A control concept for the LVAD which aims to preserve right-sided circulatory function, while supporting peripheral perfusion, is proposed     

Disturbed trafficking of dystrophin and associated proteins in targetoid phenomena after chronic muscle denervation

Dystrophin and associated proteins form a complex with an important role at the sarcolemma. Expression of this protein complex is highly regulated during development and regeneration. In order to better understand assembling patterns of these proteins, we have studied their expression in targetoid-like phenomena found in human muscle after chronic denervation, a situation known to give rise to abnormal protein trafficking. In eight biopsies of patients with chronic denervation, mainly resulting from amyotrophic lateral sclerosis, we found a number of targetoid phenomena. Selective accumulation of a number of sarcolemmal and sarcoplasmatic proteins occurred in targetoid phenomena. The larger majority of them contained gamma-sarcoglycan (gammaSG), but none contained the developmental heavy chain myosin isoform. In a series of 166 targetoid phenomena which could be studied with 17 different antibodies recognizing sarcolemmal and cytoplasmatic proteins, a high level of colocalization of gammaSG with desmin and alpha-actinin was found. Colocalization rate was much lower with other proteins, including other members of the dystrophin-associated protein complex. These data show that selective changes in expression of otherwise closely related proteins occur during disturbed trafficking leading to target formation. Because members of the dystrophin-associated protein complex do not accumulate in a similar fashion within targets, we suggest that a complex molecular control of gene expression and trafficking of this complex is involved after chronic muscle denervation.     

Biphasic action of vigabatrin on cortical epileptic after-discharges in rats

The time course of the anticonvulsant effect of vigabatrin against cortically induced epileptic after-discharges (ADs) was studied in freely moving rats with implanted electrodes. Adult rats (n=30) were exposed to five stimulation sessions each consisting of six stimulation series at 20-min intervals. The first session was a control one, then two groups of animals (n=10 each) were given vigabatrin (600 or 1,200 mg/kg i.p.), the control animals received physiological saline. Stimulation sessions were repeated 1, 24, 48, and 96 hours after the injection.Control animals exhibited an increased transition from the spike-and-wave type of AD to the second, limbic type and an increased intensity of movements accompanying stimulation. ADs in the second and subsequent sessions were, however, shorter than in the first session. Vigabatrin facilitated the transition to the second type of AD 1 h after administration but suppressed this transition as well as decreased the number of stimulations eliciting ADs 48 h later. AD duration and the severity of clonic seizures accompanying spike-and-wave ADs were influenced similarly. The effects of the lower dose of vigabatrin were more marked than those of the higher dose. The biphasic action of vigabatrin in our model might be due either to uneven changes of GABA concentration in different brain structures or to an additional mechanism of action.Our results in a cortical model of seizure demonstrate that the sequence of pro- and anticonvulsant actions of vigabatrin is not restricted to seizures of limbic origin and might represent a general phenomenon.     

Abnormalities of motor imagery associated with somatic passivity phenomena in schizophrenia

Some patients with schizophrenia report that their limbs are under the control of an alien force (motor passivity). This is hypothesised to be due to the dysfunction of an internal self-monitoring system that normally permits distinctions between internally generated and external influences on intentional behaviour. Motor imagery is the mental simulation of specific motor actions and it is based upon the internal representation of intended but unexecuted motor actions. Therefore, the generation of motor imagery should be impaired in schizophrenia characterised by passivity phenomena. The generation of motor imagery was compared using the visually guided pointing task (VGPT) and the Florida praxis imagery questionnaire (FPIQ) between patients with schizophrenia characterised by high levels of passivity symptoms (passivity) and patients without passivity symptoms (no-passivity). In both the passivity and no-passivity groups, the speed of real motor sequences on the VGPT was constrained by the distance of the movement and the width of the target in accordance with Fitts' law. For the no-passivity group, the same relationship was found for imagined movements. However, in the passivity group, imagined movements were not constrained by Fitts' law. The effect of a 2-kg load to the limb performing real or imagined movements on the VGPT was identical in both groups. The duration of imagined movements was slowed although the duration of real movements was unaffected. The FPIQ showed that the passivity group had difficulty answering questions that required them to imagine kinaesthetic aspects of performing simple gestures. These results suggest that passivity phenomena in schizophrenia are associated with a specific inability to represent the timing of motor actions internally. This is consistent with the hypothesis that patients with passivity phenomena have difficulty with maintaining an internal representation of intentional behaviour.     

进化视角下的经络实质-经络是一种返祖性状(英文)

目前诸多经络认识很可能均部分正确,深化认识应摈弃门户之见统一理解,作者认为最关键的是需选择适当的研究视角。一般地说,从进化角度考察经络实质不仅是科学的,也是获取统一认识的捷径。作者在广泛考察动物进化史中可能的经络原型后,发现子午干神经系与经络系统有类同的特点,即经络系统可能是原始子午干神经系的进化遗迹。这种认识可称之经络实质的“返祖”或“古迹”理论,现已有的研究成果几乎均可从不同侧面支持此理论且可合理兼容协调古今各种经络认识,提示有关视角值得作为深化经络研究的基础。