Preconditioning cortical lesions reduce the incidence of peri-infarct depolarizations during focal ischemia in the Spontaneously Hypertensive Rat: interaction with prior anesthesia and the impact of hyperglycemia

The relationship between peri-infarct depolarizations (PIDs) and infarction was investigated in a model of preconditioning by cortical freeze lesions (cryogenic lesions, CL) in the Spontaneously Hypertensive Rat. Small (< 5 mm³) lesions produced 24 hours before permanent focal ischemia were protective, without impacting baseline cerebral blood flow (CBF) and metabolism. Prior CL reduced infarct volume, associated with improved penumbral CBF as previously showed for ischemic preconditioning. The brief initial procedure avoided sham effects on infarct volume after subsequent occlusion under brief anesthesia. However, under prolonged isoflurane anesthesia for perfusion monitoring both sham and CL rats showed reduced PID incidence relative to naive animals. This anesthesia effect could be eliminated by using α-chloralose during perfusion imaging. As an additional methodological concern, blood glucose was frequently elevated at the time of the second surgery, reflecting buprenorphine-induced pica and other undefined mechanisms. Even modest hyperglycemia (>10 mmol/L) reduced PID incidence. In normoglycemic animals CL preconditioning reduced PID number by 50%, demonstrating associated effects on PID incidence, penumbral perfusion, and infarct progression. Hyperglycemia suppressed PIDs without affecting the relationship between CBF and infarction. This suggests that the primary effect of preconditioning is to improve penumbral perfusion, which in turn impacts PID incidence and infarct size.     

How electrodiagnosis predicts clinical outcome of focal peripheral nerve lesions

This article reviews the electrodiagnostic (EDX) prognostic factors for focal traumatic and nontraumatic peripheral nerve injuries. Referring physicians and patients often benefit from general and nerve‐specific prognostic information from the EDX consultant. Knowing the probable outcome from a nerve injury allows the referring physician to choose the best treatment options for his/her patients. Nerve injuries are variable in their mechanism, location, and pathophysiology. The general effects of the injuries on nerve and muscle are well known, but more research is needed for nerve‐specific information. Several factors currently known to influence prognosis include: nature of the nerve trauma, amount of axon loss, recruitment in muscles supplied by the nerve, the extent of demyelination, and the distance to reinnervate functional muscles. This article reviews these general concepts and also nerve‐specific EDX measures that predict outcome after focal neuropathies. Muscle Nerve 52:321–333, 2015     

Role of the Fyn −93A>G polymorphism (rs706895) in acute rejection after liver transplantation

The tyrosine kinase Fyn phosphorylates tyrosine residues on key targets involved in early T-cell signal transduction. T-cell signal transduction is one essential step for acute transplant rejection. The aim of this study was to evaluate the association of Fyn −93A>G single nucleotide polymorphism (SNP) (rs706895) with the susceptibility to acute rejection episodes in liver transplantation. In total, 72 liver transplant recipients with one biopsy proven acute rejection (S-BPAR), 56 with multiple BPAR (M-BPAR), 105 without BPAR (No-BPAR), and 145 healthy controls were enrolled in this case-control study. The SNP was genotyped by polymerase chain reaction–allele specific restriction enzyme analysis (PCR–ASRA) and was analyzed for a recessive and a dominant model. The Fyn −93G allele exhibits in healthy controls a statistically significant lower frequency than in liver recipients (18% vs. 24%; p = 0.046) or in liver recipients with BPAR (18% vs. 27%; p = 0.017). However, the genotype and allele frequencies of the Fyn −93A>G SNP demonstrate no significant differences between recipients with acute rejection episodes (S-BPAR and M-BPAR) and No-BPAR recipients. Thus our results provide no evidence that the Fyn −93A>G SNP contributes to the susceptibility to acute liver transplant rejection in a Caucasian population.     

苏合香对大鼠急性局灶性脑缺血损伤的作用初探

[目的]研究苏合香预处理对健康大鼠生理状态下的安全性及急性局灶性脑缺血病理损伤状态下的反应性,初步探索苏合香药理预适应对急性脑缺血损伤的影响,为阐明苏合香"开窍"作用提供部分实验依据。[方法]将健康雄性SD大鼠随机分为假手术组(Sham)、对照组(Vehicle)及苏合香各剂量组[Storax 0.1、0.2、0.4、0.8、1.6 g/(kg·d)]。监测预给药期间各组大鼠体质量及肝肾功能以确保用药安全性。预给药5 d后,线栓法建立大鼠大脑中动脉阻塞(MCAO)模型,激光多普勒血流检测仪(LDF)监测脑血流以评价、筛选模型,于缺血24 h时评价药效:改进的Zea Longa神经功能评分评价神经功能缺损,2,3,5-氯化三苯基四氮唑(TTC)染色评价脑梗死体积、半球水肿率,并计算总死亡率,同时检测凝血四项以观察大鼠脑缺血急性期凝血功能。[结果]Storax 1.6 g/(kg·d)组连续灌胃给药数日后,大鼠体质量较同时同点其他各组体质量明显降低(P0.05),血浆谷丙转氨酶(ALT)、尿素(CREA)水平显著升高(P0.05),故于后续实验中取消该组以确保用药安全;与对照组比较,Storax 0.1、0.2、0.4、0.8 g/(kg·d)各组能显著降低大鼠脑缺血后半球水肿率及神经功能评分(P0.05),Storax 0.2、0.4、0.8 g/(kg·d)各组能显著降低脑梗死体积比(P0.05),并有降低死亡率的趋势;Storax 0.2、0.4、0.8 g/(kg·d)各组能显著延长血浆凝血酶原时间(PT)、活化部分凝血活酶时间(APTT)并降低纤维蛋白原(FIB)含量(P0.05)。[结论]苏合香药理预适应可使大鼠急性局灶性脑缺血后病理损伤程度减轻,显示其潜在的抗脑缺血作用前景,其抗脑缺血损伤作用可能与苏合香通过改善缺血后血液高凝状态而改善脑血流有关,或为苏合香"开窍"机制之一;Storax 0.8 g/(kg·d)组同时具有药理作用及部分毒理作用,Storax 0.1、0.2、0.4 g/(kg·d)组所用剂量可视为相对安全、有效。     

Enhanced constitutive invasion activity in human nontumorigenic keratinocytes exposed to a low level of barium for a long time

We have recently demonstrated that exposure to barium for a short time (≤4 days) and at a low level (5 µM = 687 µg/L) promotes invasion of human nontumorigenic HaCaT cells, which have characteristics similar to those of normal keratinocytes, suggesting that exposure to barium for a short time enhances malignant characteristics. Here we examined the effect of exposure to low level of barium for a long time, a condition mimicking the exposure to barium through well water, on malignant characteristics of HaCaT keratinocytes. Constitutive invasion activity, focal adhesion kinase (FAK) protein expression and activity, and matrix metalloproteinase 14 (MMP14) protein expression in primary cultured normal human epidermal keratinocytes, HaCaT keratinocytes, and HSC5 and A431 human squamous cell carcinoma cells were augmented following an increase in malignancy grade of the cells. Constitutive invasion activity, FAK phosphorylation, and MMP14 expression levels of HaCaT keratinocytes after treatment with 5 µM barium for 4 months were significantly higher than those of control untreated HaCaT keratinocytes. Taken together, our results suggest that exposure to a low level of barium for a long time enhances constitutive malignant characteristics of HaCaT keratinocytes via regulatory molecules (FAK and MMP14) for invasion. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 161–167, 2015.     

The effect of rebreathing and hyperventilation on retinal and choroidal vessels measured by spectral domain optical coherence tomography

Objective: The purpose of this study was to examine the vasoreactivity in retina and choroid of the healthy eyes in response to experimentally altered partial arterial pressure of carbon dioxide (PaCO₂) using a non-invasive technique, spectral domain optical coherence tomography (SD-OCT).

Materials and methods: The study included non-smoking participants between 18 and 35 years of age, having visual acuity of 20/20 and with no systemic and ocular diseases. At baseline, the participants breathed room air (normocapnia). Hypocapnia was created with the help of hyperventilation; for this, the participants were instructed to draw deep and quick breaths, resulting one breathing cycle per 2?s. To create hypercapnia subjects rebreathed from a 5?l bag at least 3?min. Choroidal thickness and retinal artery diameter were measured at baseline, and hyperventilation and rebreathing conditions by SD-OCT.

Results: Twenty eyes of 20 healthy subjects were included in this study. Their mean age was 24.90?±?5.32 years. Hyperventilation caused a significant reduction in choroidal thickness, compared with baseline, at all points; whereas rebreathing caused no significant change at all points. The mean diameters of the arteries were 151.80?±?7.88?μm, with a significant decline to 148.90?±?7.25?μm at hyperventilation condition and a significant increase to 153.50?±?7.88?μm at rebreathing condition (p?=?0.018, p?=?0.043, respectively).

Conclusion: This study demonstrated that, SD-OCT was a useful tool in measuring the ocular vascular response under hypercapnia and hypocapnia conditions. These findings may be helpful for further understanding the physiological nature of ocular blood flow and this preliminary study provides a basis for future studies.