An ultrastructural and immunohistochemical study of microcystic meningioma with emphasis on matrix proteins and connexin 26 type gap junctions

Although the histopathological subtypes of meningioma do not themselves appear to have prognostic significance, they are collectively important for defining the overall histopathological entity of microcystic meningioma (MCM) and allowing a distinction from other intracranial tumors, such as capillary hemangioblastoma, glioma, and metastatic renal cell carcinoma showing similar histology. Four cases of MCM were analyzed by conventional histology, immunohistochemistry, and electron microscopy. The present series of MCM was characterized by spindle- or cobweb-shaped tumor cells, characteristically associated small blood vessels, and a peculiar microcystic pattern. Among the microcystic meningeal tumor tissue, small areas of conventional subtypes were identified. Immunohistochemically, tumor cells showed the mesenchymal features of vimentin positivity and a rich distribution of matrix proteins around tumor cells. They lacked epithelial marker positivity but were faintly EMA positive. Ultrastructurally, primitive cellular junctions, desmosomes, and gap junctions were frequently seen between tumor cells. The gap junctions correlated with connexin 26 immunoreactivity. Although lacking an obvious epithelial nature, these features could be interpreted as showing an abortive differentiation mimicking meningothelial (arachnoidal) cells, which, physiologically, regulate cerebrospinal fluid between blood vessels and brain parenchyma.     

Can low intensity pulsed ultrasound (LIPUS) be used as an alternative to revision surgery for patients with non-unions following fracture fixation?

BackgroundNon-union is a significant complication of fracture fixation surgery, and can negatively impact a patient’s quality of life. Low intensity pulsed ultrasound (LIPUS) has been used to treat delayed or non-unions previously in the literature. The aim of this study was to determine the success rate of LIPUS treatment in patients with chronic fracture non-unions, and to establish the effect of systemic or local factors on its success.MethodsThis was a retrospective, observational study which included all patients undergoing LIPUS treatment in a single institution. Patients deemed suitable for LIPUS underwent treatment for a period of 6 months from initiation. They were followed up with sequential radiographs to assess union at intervals of 6 weeks, 3 months, 6 months and 1 year. LIPUS treatment was considered to be successful when patients achieved clinical and radiological union, without the need for revision surgery.ResultsA total of 46 patients were included in the study; 8 were lost to follow – up, leaving 38 patients for the final analysis. The mean age of patients was 47.03 ± 19.7 with a male to female ratio of 1.2:1. Union was achieved in 57.89%; the rest underwent revision surgery. There was no significant association between outcomes after LIPUS treatment and patients’ age, gender, smoking status or type of non-union. Patients with a small inter-fragment bone gap were more likely to have a successful outcome after LIPUS (p = 0.041). Time to treatment did not have a statistically significant impact on outcomes after LIPUS. Interestingly, all 6 patients with diabetes in the study managed to achieve union after LIPUS.ConclusionsThis study demonstrates that LIPUS is not successful in a large proportion of patients with established fracture non-unions. However, it does represent a low risk treatment modality as an alternative to revision surgery, especially for patients with diabetes who have a small inter – fragment bone gap. More research in the form of large randomised controlled trials needs to be carried out to further assess the role of LIPUS in the treatment of non-unions.     

人均预期寿命差距的健康决定因素贡献度研究

目的:系统性分解健康决定因素不平等对人均预期寿命差距的贡献度,探索公共政策可干预的优先领域,提出缩小国家或地区间健康差距的政策建议.方法:利用1990—2017年跨国面板数据,在分组构建宏观健康生产方程和回归分析的基础上,利用Oaxaca-Blinder分解技术对高、低寿命国家组间差距进行分解,计算出各因素对寿命差距的贡献度.结果:总体人均预期寿命差距绝大部分(92.8%)可由健康决定因素不平等解释(可干预的资源型差异),不可解释部分(难以干预的结构型差异)仅占7.2%;在可解释部分,受教育程度贡献度最高(34.4%),其次是人均GDP(26.8%)和安全饮水覆盖率(26.2%),三者共占87.4%;在因素分类贡献度中,社会经济地位因素对于寿命差距贡献度最高(60.9%),医疗卫生体系因素贡献度为6.5%.结论:健康弱势国家应主动建立以健康为导向的资源可持续发展路径,必要时采取国家内部跨地区资源转移战略;明确健康发展的优先领域,兼顾跨领域资源统筹协调;加强发达国家对弱势国家资源发展的国际投资与援助,协作构建人类卫生健康共同体.     

运动对骨骼－肌腱界面愈合组织的影响

利用纽西兰兔作体内实验，来分析手术后石膏固定，笼内活动，连续被动性活动三种不同的复健方法对肌腱－骨骼间界面愈合组织的影响。结果显示在术后第１５天愈合组织所能承受的最大张力，笼内活动组为０．８７５ｋｇ，石膏固定组为２．０１４ｋｇ，是笼内活动组的２３１．５２％，而连续被动性活动组为２．６３８ｋｇ，是笼内活动组的２６１．３５％。石膏固定组虽有很高的张力，但关节内粘连也较多。     

Some technical improvements for the voltage clamp with the double sucrose gap

Summary A new double sucrose gap chamber using electrodes of high stability and low resistance is described. The size of each sucrose gap and the central node can be modified independently so that this chamber is suitable for research on multicellular or unicellular excitable preparation under voltage clamp conditions. The shape of the central channel is made so as to reduce the series resistance between the preparation and the recording electrode to a minimum. A window made in the floor of the chamber allows to observe the preparation under a microscope.This work was performed under the I.N.S.E.R.M. grant no. 17.75.40.     

犬陈旧性心肌梗死时连接蛋白43的分布

目的：探讨陈旧性心肌梗死时心肌缝隙连接蛋白43（connexin 43,Cx43)的分布特征。方法：结扎犬冠状动脉造成心肌梗死,术后恢复40－50d,用改良的免疫细胞化学法显示心肌梗死区,边缘带及非缺血区Cx43的分布,半定量分析不同部位Cx43的分布密度。结果：与正常心肌相比,梗死病灶及其邻近区域Cx43的分布出现明显紊乱：梗死中心区Cx43完全消失;边缘带Cx43呈现不均匀消失,少量Cx43分布于岛状或半岛状尚存活的心肌;心肌细胞端－端相接处的Cx43严重消失,而细胞侧－侧相接处的Cx43仍有部分存在。非缺血区Cx43的密度和分布与正常心肌相比无明显改变。结论：陈旧性心肌梗死时Cx43的数量和分布呈现高度不均一性,尤其在边缘带Cx43的分布特点是形成局部传导阻滞和折返性心律失常的结构基础。     

受抑全内反射调Q开关原理装置的研究

根据薄膜理论基础,分析了受抑全内反射（ＦＴＩＲ）的理论机制,并导出相应的光线透过率及反射率公式,绘制出透射率、反射率随棱镜相对间隙ｄ／λ、入射角θ。的变化曲线。并建立了一套ＦＴＩＲ组合测试原理实验装置,得到了透过及发射光脉冲曲线,通过实验地其特性进行了具体分析。     

Aerosolized prostacyclin and inhaled nitric oxide in septic shock — different effects on splanchnic oxygenation?

Objectives To compare the effects of inhaled nitric oxide and aerosolized prostacyclin (PGI₂) on hemodynamics and gas exchange as well as on the indocyanine-green plasma disappearance rate and gastric intramucosal pH in patients with septic shock.Design Prospective, randomized, interventional clinical study.Setting Intensive care unit in a university hospital.Patients Sixteen patients with pulmonary hypertension and septic shock according to the criteria of the ACCP/SCCM consensus conference all requiring norepinephrine and/or epinephrine to maintain mean arterial blood pressure above 65 mmHg.Methods and interventions Patients were randomly assigned to receive either nitric oxide or aerosolized prostacyclin. Nitric oxide was inhaled using a commercially available delivery system, prostacyclin was administered with a modified ultrasound nebulizer. Both nitric oxide and prostacyclin were incrementally adjusted to obtain a 15% decrease of mean pulmonary artery pressure. Hemodynamics and gas exchange as well as indocyaninegreen plasma disappearance rate and gastric intramucosal pH were determined at baseline after 90 min in steady state, after 90 min of nitric oxide inhalation or prostacyclin aerosol administration had elapsed in stable conditions, and after 90 min in stable conditions after nitric oxide or prostacyclin with-drawal.Results Both inhaled nitric oxide and aerosolized prostacyclin selectively reduced the mean pulmonary artery pressure from 35±4, 30±4 mmHg (p<0.05) and 34±4 to 30±3 mmHg (p<0.05) respectively; after removal of nitric oxide and prostacyclin, the mean pulmonary artery pressure returned to the baseline values. Systemic hemodynamics remained unaltered during the vasodilator treatment. While the mean PaO₂ was not significantly influenced, it increased in 4/8 of the NO- and 3/8 of the PGI₂ — treated patients. Neither of the drugs influenced indocyanine-green plasma disappearance rate, but prostacyclin — unlike nitric oxide — significantly increased gastric intramucosal pH (from 7.26±0.07 to 7.30±0.05,p<0.05) which remained elevated in four of these patients after prostacyclin removal, and decreased the arterial-gastric mucosal pressure of carbon dioxide gap from 19±6 to 15±4 mmHg (p<0.05).Conclusions Our data suggest that aerosolized prostacyclin — unlike nitric oxide — has similar beneficial effects on splanchnic perfusion and oxygenation as intravenous prostacyclin without detrimental effects on systemic hemodynamics. The different effects of prostacyclin and nitric oxide might be explained by the longer half-life of prostacyclin associated with a certain spillover into the systemic circulation.Presented in part at the Masterclass Symposium Sepsis in the ICU, Maastricht, June 27–29, 1995     

Closing the theory—practice gap: a model of nursing praxis

Summary

• ? Despite the efforts of nursing theorists, educationalists and practitioners, the theory-practice gap continues to defy resolution. This paper argues that only by reconsidering the relation between theory and practice can the gap be closed.
• ? Drawing upon ideas from teaching and other practice-based disciplines, including nursing, the article suggests that the current model of viewing theory as informing and controlling practice should give way to a mutually enhancing model in which theory is derived from practice, and in turn influences future practice.
• ? This coming together of theory and practice is referred to as nursing praxis, and suggests that informal theory should be unique to each individual encounter with each patient.
• ? The clinical nurse is thus not only a practitioner, but a theorist and researcher, who responds to patients not according to some grand, inflexible theory, but by the process of reflection-in-action, drawing upon their expertise and a repertoire of past experiences and encounters.

     

How do normal subjects learn a simple adaptative task: How and why do paranoid schizophrenic patients fail?

Summary The authors studied the behavior of normal subjects and paranoid schizophrenic patients in a simple problem-solving situation. The schizophrenics were divided into two sample groups, one of individuals under treatment and the other of individuals not under treatment.The learning process involved in this problem-solving situation is very similar to an instrumental conditioning, and can be understood by means of the following assumptions: (1) the subjects use decision functions in reacting to the stimuli, although they may be not fully aware of this; (2) learning is the result of successive transformations of these decisions in the course of time; (3) the changes have specific probabilities and are related to (a) those responses which are made to the latest stimuli, and (b) a differential probability for decision functions which were effective, or only interrupted painful reinforcement, or were completely ineffective.In schizophrenics further factors of importance were (1) an inertia factor and (2) the rigidly continued use of unsuccessful or only partially successful decision criteria.The authors used a systems theory based on Galois field theory and a calculus of operators specifying three groups of subjects. A computer program based on these hypotheses was tested in a simulation experiment.The statistical evaluation of the results showed a congruence between the theoretical approach and the experimental data.This work was carried out with financial support from the Institute de Alta Cultura, Lisbon, between 1970 and 1974