Initial experience with a self-expanding retrievable stent for recanalization of large vessel occlusions in acute ischemic stroke

Introduction  

Quicker recanalization results in better clinical outcomes in patients with acute ischemic strokes. We describe our experience with the use of a self-expanding, fully retrievable stent in acute intracranial occlusions.     

Comparison of pre- and postcontrast 3D time-of-flight MR angiography for the evaluation of distal intracranial branch occlusions in acute ischemic stroke

BACKGROUND AND PURPOSE: Three-dimensional time-of-flight (TOF) MR angiography is used routinely in stroke workup to detect arterial occlusions, but a major drawback is its inadequate depiction of vessels with slow or in-plane flow. We hypothesized that the use of contrast-enhanced MR angiography improves delineation of vessels with diminished or absent flow on precontrast MR angiograms. METHODS: Pre- and postcontrast 3D TOF MR angiograms were acquired in 55 consecutive patients with acute stroke. Patency of 480 intracranial vessels was assessed on both the pre- and postcontrast angiograms. Diffusion-weighted (DW) and perfusion-weighted (PW) imaging data were also obtained and results correlated with those of pre- and postcontrast MR angiography. RESULTS: For 50 abnormal vessel segments seen on precontrast MR angiograms, postcontrast MR angiograms resulted in change in the vascular signal intensity in 70% (35 vessel segments); 94% of these changes showed a greater extent of vessel patency. Venous and soft-tissue contrast enhancement had no effect on assessment in 95% of all 480 vessels examined. Interobserver reliability was moderate, with postcontrast interpretation (kappa = 0.48) showing a slight improvement over precontrast interpretation (kappa = 0.41). Good agreement was found between the TOF results and the pooled DW and PW imaging results. CONCLUSIONS: Compared with precontrast 3D TOF MR angiograms, postcontrast 3D TOF angiograms improve assessment of intracranial vessel patency in acutely ischemic vascular territories. In some patients, an improved understanding of acute ischemic stroke was obtained by viewing the pre- and postcontrast images. Postcontrast MR angiography should be included in the MR evaluation of acute stroke.     

Effects on the buoyant density of rabbit platelets of ADP and agents that increase the concentration of cyclic AMP

Rabbit platelets were aggregated by adenosine diphosphate (ADP), allowed to deaggregate and then separated into density subpopulations by centrifugation through discontinuous Stractan density gradients. Although ADP causes little or no release of the contents of the amine storage granules of rabbit platelets, ADP caused a decrease in platelet density as compared with control platelets subjected to the same procedures except for exposure to ADP. The density change persisted for at least four hours. The apparent size of platelets stimulated with ADP increased initially, but returned to control values during a one-hour period. A similar decrease in platelet density was observed with an albumin density gradient. Under conditions in which aggregation did not occur in response to ADP with ethylenediaminetetraacetic acid (EDTA) in the medium, little or no decrease in platelet density was observed. Agglutination with polylysine did not change platelet density. Thus, not only agents such as thrombin and plasmin that cause the release of the contents of the platelet granules decrease platelet density, but ADP also has this effect. Platelets would be exposed to all of these stimuli during thromboembolic processes, and their effect on platelets may account for the decrease in platelet density observed previously in experiments with rabbits with indwelling aortic catheters. Agents that increase the concentration of cyclic AMP (cAMP) in platelets (PGE1, adenosine, dibutyryl cAMP, forskolin, and papaverine) also decreased platelet density. This effect persisted when the platelets were washed and resuspended in fresh medium and was also demonstrable in plasma. Platelet size was gradually increased by prostaglandin E1 (PGE1) which maintains platelets in a disc shape and does not cause the release of granule contents, indicating that the decrease in platelet density caused by PGE1 may be attributable to platelet swelling.     

004 65岁以上收缩功能正常的心衰者的临床特点

众所周知,充血性心衰(CHF)为老年人较为常见的临床综合征之一.迄今关于左室收缩功能正常的CHF老人的相关临床特点远未清楚,本文特此进行了大样本分析. 对象与方法 4842例老年人,男1922例,女2920例,年龄66～103岁.尔后人均随访1年.旨在分析老年CHF年发病率,以及左室收缩功能正常的CHF老人相关临床特点. 结果随访期内,罹发1次或以上CHF者共425例次(8.8%/年).与未患发CHF老人相比,CHF老人平均年龄更大(79±6岁:77±5岁,P＜0.001),女性居多,尤以高龄女性更多,如85岁以上的高龄女性CHF年发病率约较65～69岁女性高2倍(14%∶6.6%,P＜0.001),AMI史、房颤、高血压、糖尿病、慢性阻塞型肺病、吸烟者均多,血脂及血肌酐亦高.多变量分析表明,罹患CHF与下列因素有关:老年尤其是高龄[年龄每增加5岁的患病奇数率(OR)女性1.2,男性1.1],AMI史(OR7.3),房颤者(OR3.0),糖尿病(OR2.1),肾功能不全(血肌酐≥1.5mg/dl的OR2.0),慢性阻塞肺病(仅老年女性的OR为1.8),以及左房、左室内径增大(内径每递增1cm的OR为2.0),和左室重量增加、左室收缩末期室壁张力增高、早期跨心房血流增多.超声心动图检测结果显示,CHF老人中,左室收缩功能正常者达55%,而仅有左室舒张功能不全,且左室收缩功能正常或轻度减退者高达80%.其中女性左室收缩功能正常者尤较男性多见(67%∶42%,P＜0.001),表现为单纯左室舒张功能不良.而在左室收缩功能正常的CHF老人,常伴有左室内径较小、左室收缩末期室壁张力较低、左室重量较轻、左室收缩末期室壁厚度增加,而左室射血分数正常或仅轻度降低. 讨论以上结果提示,在老年人群中,CHF年发病率相对较高,且随年龄而增加,多数左室收缩功能正常,仅有左室舒张功能障碍,尤其是在高龄女性,亦即高龄女性左室舒张功能不全性CHF更为常见.对此,临床上更应拟出合理的防范措施,来正确诊治老年CHF综合征. (袁志敏摘)     

Hormonal effects on cell proliferation in a human erythroleukemia cell line (K562)

We have investigated the hormonal responsiveness of K562 cells using a serum-substituted in vitro clonogenic assay. Dexamethasone inhibited colony formation by the K562 cells, and the inhibitory effect could be reversed by progesterone (10(-6) M). Fluoxymesterone caused a prominent enhancement of K562 colony growth, whereas estriol had no effect. Stimulation by triiodothyronine was maximal at 10(-7) M, and the thyroid effect could be abrogated by the beta 2-adrenergic antagonist butoxamine in equimolar concentrations. Using standard tissue culture conditions, the beta-adrenergic agent isoproterenol, but not the alpha catecholamine phenylephrine, enhanced the proliferation of K562 cells. When K562 cells were grown under hormone-depleted conditions, they developed responsiveness to phenylephrine and were no longer stimulated by isoproterenol. DbcAMP and prostaglandins of the E series also caused K562 colony enhancement. Prostaglandin F2 alpha had no effect on cell proliferation. Insulin was an effective stimulant of colony formation of K562 cells, as were human growth hormone and ovine prolacin. Bovine growth hormone had no effect. Our results are consistent with the identificaiton of K562 as an erythroid line, and they indicate that K562 cells respond to endocrine hormones in a manner analogous to normal erythroid progenitors.     

Efficacy of red and infrared lasers in treatment of temporomandibular disorders — a double-blind,randomized, parallel clinical trial

Aim:

Low-level laser therapy has still not been well established, and it is important to define a standardized protocol for the treatment of temporomandibular disorders (TMDs) using low level laser. There is no consensus on controlled clinical trials concerning the best option for laser therapy with regard to wavelength. The aim of this study was to evaluate the efficacy of red and infrared laser therapy in patients with TMD, using a randomized parallel-group double-blind trial.

Methodology:

Each hemiface of 19 subjects was randomized to receive intervention, in a total of 116 sensitive points. Pain was measured at baseline and time intervals of 24 hours, 30 days, 90 days, and 180 days after treatment. Irradiation of 4 J/cm² in the temporomandibular joints and 8 J/cm² in the muscles was used in three sessions.

Results:

Both treatments had statistically significant results (P<0·001); there was statistical difference between them at 180 days in favor of the infrared laser (P?=?0·039). There was improvement in 24 hours, which extended up to 180 days in both groups.

Conclusion:

Both lasers are effective in the treatment and remission of TMD symptoms.     

Extravasating Contrast Material on Angiography Following Carotid Angioplasty and Stenting: Not Necessarily Subarachnoid Hemorrhage

We describe a case of asymptomatic extravasation of iodinated contrast material into the sulci on digital subtraction angiography following carotid angioplasty and stenting resulting in sulcal hyperdensity on computed tomography (CT). We believe the mechanism for this observation is hyperperfusion injury and that in the absence of any associated clinical signs, it should not be considered alarming for subarachnoid hemorrhage.