Cerebral monitoring during carotid endarterectomy using near-infrared diffuse optical spectroscopies and electroencephalogram

Intraoperative monitoring of cerebral hemodynamics during carotid endarterectomy (CEA) provides essential information for detecting cerebral hypoperfusion induced by temporary internal carotid artery (ICA) clamping and post-CEA hyperperfusion syndrome. This study tests the feasibility and sensitivity of a novel dual-wavelength near-infrared diffuse correlation spectroscopy technique in detecting cerebral blood flow (CBF) and cerebral oxygenation in patients undergoing CEA. Two fiber-optic probes were taped on both sides of the forehead for cerebral hemodynamic measurements, and the instantaneous decreases in CBF and electroencephalogram (EEG) alpha-band power during ICA clamping were compared to test the measurement sensitivities of the two techniques. The ICA clamps resulted in significant CBF decreases (-24.7 ± 7.3%) accompanied with cerebral deoxygenation at the surgical sides (n = 12). The post-CEA CBF were significantly higher (+43.2 ± 16.9%) than the pre-CEA CBF. The CBF responses to ICA clamping were significantly faster, larger and more sensitive than EEG responses. Simultaneous monitoring of CBF, cerebral oxygenation and EEG power provides a comprehensive evaluation of cerebral physiological status, thus showing potential for the adoption of acute interventions (e.g., shunting, medications) during CEA to reduce the risks of severe cerebral ischemia and cerebral hyperperfusion syndrome.     

Carotid artery stenosis and tachyarrhythmias: regional cerebral blood flow during high-rate ventricular pacing after one vessel occlusion in rats

The aim of the present study was to investigate the effect of hypotensive tachycardias on cerebral blood flow (CBF) in the presence of significant carotid stenosis. The experiments were performed in 57 spontaneously breathing rats during arterial normoxia and normocapnia anesthetized with thiobarbital. CBF was determined with radio-labeled microspheres during control conditions (normofrequent sinus rhythm, normotension; group A; n = 15), during high-rate left ventricular pacing (660–840 ppm) at normotension (group B₁; n = 13), borderline hypotension (group B₂; n = 15) and severe hypotension (group B₃; n = 7). In addition, CBF measurements were performed during borderline hypotension induced by hemorrhage (group C; n = 7). Global CBF was 1.09 ± 0.29 ml g^–1 min^–1 in group A, 0.93 ± 0.40 in group B₁, 0.68 ± 0.31 in group B₂ (P < 0.05 vs. A), 0.42 ± 0.16 in group B₃ (P < 0.05 vs. A) and 0.83 ± 0.2 in group C. The highest CBF values were found in the cerebellum (A; 1.43 ± 0.5 ml g^–1 min^–) and the lowest in the postocclusive tissue of the ipsilateral hemisphere (A; 0.74 ± 0.2 ml g^–1 min^–1). In all groups a 15% mean CBF reduction in the right hemispherical cerebrum in comparison to the left hemisphere was observed (P < 0.01). In contrast, hemispherical CBF of the cerebellum did not differ. The CBF blood pressure relationship shifted to lower CBF values, the threshold of CBF regulation shifted to higher blood pressure values in the tissue regions distal to the occluded vessel during hypotensive tachycardias. One carotid artery occlusion and high rate ventricular pacing seem to be a reliable model for quantifying cerebral hemodynamics during arrhythmias in the presence of carotid stenoses. Using this experimental approach it was demonstrated that hypotensive tachycardias and obstructions within the ectracranial carotid vascular bed such as arterial vessel stenoses and occlusions have an additive effect on CBF reduction.Abbreviations CBF cerebral blood flow - P_m mean arterial blood pressure Correspondence to: A. Hagendorff     

磁共振全脑容积动脉自旋标记成像评价单侧颈动脉狭窄患者脑血流动力学的初步研究

目的探讨磁共振全脑容积灌注3D动脉自旋标记（3DASL）成像在单侧颈动脉狭窄或闭塞中的应用价值。方法对连续36例单侧颈动脉狭窄患者（经数字减影血管造影（DSA）验证）行颈部磁共振血管成像（MRA）与头部MR3DASL检查。检验颈部MRA与DSA在狭窄程度上诊断的一致性。以DSA诊断的狭窄程度为标准,将36例患者分成轻、中、重3组,对3DASL所测得的患侧,健侧脑血流量（CBF）比率进行方差分析。以临床症状为标准,将重度狭窄的患者分为有症状组和无症状组,分析2组患侧,踺侧CBF比率的统计学意义。结果颈部MRA与DSA在动脉血管狭窄程度上的诊断,经Kappa行一致性检验,有很强的一致性（Kappa〉0．75,P〈0．05）。轻、中度狭窄组间患侧楗侧CBF比率差别无统计学意义（P〉O．05）;重度狭窄组与轻、中度狭窄组患侧健侧CBF比率差别均有统计学意义（P〈0．01）。重度狭窄患者的有症状组与无症状组患侧,睦侧CBF比率差别有统计学意义（P〈0．01）。结论3DASL技术作为一种安全、无创和可重复的检查方式,配合颈部MRA,对评价单侧颈动脉狭窄患者脑血流动力学状况在临床诊治方面有重要意义。     

Type 2 proatlantal intersegmental artery associated with persistent trigeminal artery diagnosed by MR angiography

Purpose

The type 2 proatlantal intersegmental artery (PIA) is a rare anastomosis between the external carotid artery (ECA) and vertebral artery (VA) that passes through the foramen magnum. The persistent trigeminal artery (TA) is the most common anastomosis between the internal carotid artery (ICA) and basilar artery. The purpose of this paper is to present the first case of a type 2 PIA associated with an ipsilateral persistent TA diagnosed using magnetic resonance (MR) angiography, and we briefly discuss the embryology of this rare anomaly.

Methods

An 83-year-old man with cerebral infarctions underwent cerebral MR imaging, and head and neck MR angiography using a 1.5?T imager. MR angiography was obtained using the standard non-contrast three-dimensional time-of-flight technique.

Results

MR angiography showed aplasia of the proximal left VA and a large anastomotic artery between the left ECA and distal left VA that passed through the foramen magnum, indicative of a type 2 PIA. This patient also had an anastomosis between the precavernous segment of the left ICA and midbasilar artery via a lateral course, indicative of a lateral-type persistent TA.

Conclusion

We present the first case of type 2 PIA associated with ipsilateral lateral-type persistent TA diagnosed by MR angiography. MR angiography should be performed including the carotid bifurcation to find more frequently extracranial arterial variations, including type 2 PIAs.     

Can contrast-enhanced ultrasound with second-generation contrast agents replace computed tomography angiography for distinguishing between occlusion and pseudo-occlusion of the internal carotid artery?

OBJECTIVE:

The purpose of this study was to evaluate the effectiveness of contrast-enhanced ultrasound with a second-generation contrast agent in distinguishing between occlusion and pseudo-occlusion of the cervical internal carotid artery, comparing it with that of conventional Doppler ultrasound and the gold standard, computed tomography angiography.

METHOD:

Between June 2006 and June 2012, we screened 72 symptomatic vascular surgery outpatients at a public hospital. Among those patients, 78 cervical internal carotid arteries were previously classified as occluded by Doppler ultrasound (without contrast). The patients were examined again with Doppler ultrasound, as well as with contrast-enhanced ultrasound and computed tomography angiography. The diagnosis was based on the presence or absence of flow.

RESULTS:

Among the 78 cervical internal carotid arteries identified as occluded by Doppler ultrasound, occlusion was confirmed by computed tomography angiography in only 57 (73.1%), compared with 59 (77.5%) for which occlusion was confirmed by contrast-enhanced ultrasound (p>0.5 vs. computed tomography angiography). Comparing contrast-enhanced ultrasound with Doppler ultrasound, we found that the proportion of cervical internal carotid arteries classified as occluded was 24.4% higher when the latter was used (p<0.001).

CONCLUSIONS:

We conclude that, in making the differential diagnosis between occlusion and pseudo-occlusion of the cervical internal carotid artery, contrast-enhanced ultrasound with a second-generation contrast agent is significantly more effective than conventional Doppler ultrasound and is equally as effective as the gold standard (computed tomography angiography). Our findings suggest that contrast-enhanced ultrasound could replace computed tomography angiography in this regard.     

颈内动静脉与颅底骨三维空间关系

目的 :显示对比正常侧和病变侧颈内动静脉与周围骨结构的解剖关系 ,以完善术前准备。方法 :10例颌颈部肿瘤患者 ,术前行颈动脉三维CT血管成像 (CTA) ,同步注射造影剂 ,螺旋CT对病变区血管段进行重点薄层螺旋扫描 ,由EasyVision工作站三维重建。结果 :5例颈外动脉和颈内静脉受压狭窄 ,其中 3例出现颈总动脉、颈内动脉向内侧移位 ,另 1例左侧颈内动脉动脉瘤清晰定位。CTA能够显示病变区血管段 (包括颈总动脉、颈内动脉、颈外动脉、颈内静脉 )与下颌骨、舌骨、颈椎、颅底骨结构的三维解剖关系 ,进行旋转、放大 ,三维测量 ,多视角观察 ,无重叠干扰。结论 :对颌颈、口咽部肿瘤患者术前CTA检查 ,能够判断颈部大血管的情况及颈部巨大肿瘤造成颈内动脉移位 ,CTA可显示血管性肿瘤的三维形状和与颅底骨空间关系 ,为手术入路及术式提供参考 ,有助于降低手术风险     

Hemodilution with liposome-encapsulated low-oxygen-affinity hemoglobin does not attenuate hypothermic cerebral ischemia in rats

Hypothermia decreases cerebral metabolism and increases hemoglobin oxygen affinity. A hypothesis that the reversal of increased oxygen affinity would further attenuate hypothermic cerebral ischemia was tested by evaluating the effects of liposome-encapsulated hemoglobin (LipoHb) with low oxygen affinity (P₅₀ = 40–50 mmHg) on hypothermic incomplete cerebral ischemia. Wistar rats were randomly assigned to one of the following two groups: (A) exchange transfusion with LipoHb solution (Hb = 6 g/dl) (LipoHb, n = 5), (B) no exchange transfusion (control, n = 5). After surface cooling to 22°C, forebrain ischemia was induced for 15 min by bilateral carotid artery occlusion combined with a decrease in the mean arterial pressure (MAP) to 40 mmHg. ³¹P-magnetic resonance spectroscopy was performed during ischemia and 45 min of reperfusion. After reperfusion, MAP was significantly higher in the control group than in the LipoHb group (P < 0.01), although there were no significant differences during ischemia. Intracellular pH and phosphocreatine (PCr) levels decreased during ischemia and returned to the preischemic level in both groups following reperfusion. The LipoHb group had a significantly larger decrease and smaller recovery in PCr than the control group (P < 0.0001). Althouth β-adenosine triphosphate decreased during ischemia in the LipoHb group, it increased in the control group (P < 0.0001). Inorganic phosphate (Pi) increased during ischemia and decreased to the normal value after reperfusion. The LipoHb group experienced a significantly larger production of Pi than the control group (P = 0.02). Hemodilution with high-P₅₀ LipoHb does not reduce ischemic energy depletion induced by hypothermic incomplete forebrain ischemia in rats.     

彩超对脑梗死患者颈动脉斑块的研究及临床价值分析

目的:探究彩超对脑梗死患者颈动脉斑块的研究及临床价值.方法:将157例脑梗死患者作为脑梗死组,分别进行CT血管造影检查(CT脑梗组)和彩超检查(彩超脑梗组);另纳入157例健康受试者为非脑梗死组,也分别进行CT血管造影检查(CT对照组)和彩超检查(彩超对照组).比较四组颈动脉斑块诊断的准确性及影像资料图质量.结果:CT...     

Influence of posture on middle cerebral artery mean flow velocity in humans

We determined middle cerebral artery, common carotid artery and temporal superficial artery Doppler derived flow velocities in ten subjects for 10 min after change in posture. Maximal changes were observed after about 3 min. The 10° head-down tilt position increased blood velocities in the common carotid artery by 13% (SD 4)% (P < 0.001), in the middle cerebral artery by,6% (SD 3)% (P < 0.001) and in the superficial temporal artery by 70% (SD 26)% (P < 0.001). In the standing position, there was an 18% (SD 9)% (P < 0.001) decrease in the common carotid blood velocities, with 14% (SD 6)% (P < 0.001) and 53% (SD 23)% (P < 0.001) reductions in the middle cerebral and superficial temporal artery velocities, respectively. At 9 min after the changes in posture, velocities in the middle cerebral artery were at the value of supine rest, whereas the common carotid blood velocity was not completely restored and deviations in the temporal artery velocity persisted. The data would suggest that cerebral blood flow is regulated with some delay and that such regulation is partially reflected in the common artery blood flow, since changes in a branch of the external carotid artery flow velocity remained.     

Carotid stenosis: what is the high-risk population?

OBJECTIVE:

Prevention is the best treatment for cerebrovascular disease, which is why early diagnosis and the immediate treatment of carotid stenosis contribute significantly to reducing the incidence of stroke. Given its silent nature, 80% of stroke cases occur in asymptomatic individuals, emphasizing the importance of screening individuals with carotid stenosis and identifying high-risk groups for the disease. The aim of this study was to determine the prevalence and the most frequent risk factors for carotid stenosis.

METHODS:

A transversal study was conducted in the form of a stroke prevention campaign held on three non-consecutive Saturdays. During the sessions, carotid stenosis diagnostic procedures were performed for 500 individuals aged 60 years or older who had systemic arterial hypertension and/or diabetes mellitus and/or coronary heart disease and/or a family history of stroke.

RESULTS:

The prevalence of carotid stenosis in the population studied was 7.4%, and the most frequent risk factors identified were mean age of 70 years, carotid bruit, peripheral obstructive arterial disease, coronary insufficiency and smoking. Independent predictive factors of carotid stenosis include the presence of carotid bruit or peripheral obstructive arterial disease and/or coronary insufficiency.

CONCLUSIONS:

The population with peripheral obstructive arterial disease and/or coronary insufficiency and carotid bruit should undergo routine screening for carotid stenosis.     

Nimodipine does not affect the flow–metabolism couple in permanent cerebral ischemia

Despite widespread investigational and clinical usage of the calcium channel blocker nimodipine, its effects on cerebral physiology in normal and ischemic brain remain poorly understood. In order to gain insight into this subject we examined the effects of nimodipine on glucose metabolism and cerebral blood flow–metabolism coupling in the rat during conditions of reproducible focal ischemia. Nimodipine-treated animals were then matched with vehicle-treated controls for both study conditions. Animals were subjected to permanent occlusion of the middle cerebral artery (MCA) along with occlusion of the common carotid arteries. Five minutes into ischemia, an intravenous infusion of nimodipine (1 µg/kg per min, n=9) or vehicle (n=9) was initiated and continued until the end of the study. Seventy-five minutes after the occlusion, [¹⁴C]2-deoxyglucose was injected into the venous catheter for the measurement of the local cerebral metabolic rate for glucose (LCMRgl), followed 25 min later by the injection of N-isopropyl-[¹²³I]p-iodoamphetamine for the measurement of local cerebral blood flow (LCBF). The animals were killed at the end of 2 h of ischemia, and the brains were processed for double-labeled autoradiography. In all animals, permanent MCA occlusion produced significant decrements in LCBF, LCMRgl, and LCBF/LCMRgl ratio in both the core of the ischemia as well as regions peripheral to the ischemia within the same cerebral hemisphere when compared with non-ischemic brain. There were no significant differences between the nimodipine-treated and vehicle-treated groups. In conclusion, nimodipine does not appear to alter cerebral blood flow or cerebral metabolism in ischemic brain.     

颈动脉切除术的体会

目的:探讨颈动脉切除术的安全检测指标,确保手术成功和患者生命安全.方法:19例行颈动脉切除的肿瘤患者采用术前体外或体内颈动脉压迫训练法,阻断颈动脉血流,通过经颅多普勒(TCD)和数字减影(DSA)检测了解脑侧支循环建立及交通动脉开放情况.术中夹闭颈总动脉,TCD检测患侧大脑前动脉(ACA)和大脑中动脉(MCA)代偿情况.结果:体外压迫训练18～45 d,体内压迫训练7～9 d达到合格标准.18例肿瘤全切,1例肿瘤包绕椎动脉入颅处行部分切除.无死亡病例和术后脑缺血及偏瘫等严重并发症.16例随访1～5 a无复发.结论:缓慢渐进的颈动脉压迫训练是促进脑侧支循环建立和患侧脑血流代偿的有效方法.TCD和DSA检测对手术成功和保障患者生命安全起决定性作用.     

Visualization of the ophthalmic artery by phase-contrast magnetic resonance angiography: a pilot study

Objective

This study aimed at investigating whether phase-contrast (PC) magnetic resonance (MR) angiography is useful for visualizing the ophthalmic artery (OA).

Methods

This prospective study enrolled 196 consecutive outpatients who underwent three-dimensional PC MR angiography. The basal image parallel to the anteroposterior dimension of the OA was extracted for analysis from the imaging data.

Results

The 99 male and 97 female subjects were aged from 10?years to 80?years (mean 47.9?years). The OAs were supplied only by the external carotid system or in combination with the internal carotid artery (ICA) in 18 subjects (9.2?%). The bilateral OAs were symmetrical in 12?%, asymmetrical in 87?%, and unidentified in 1?%. The contour of the proximal segment of the OAs could be classified into straight, curved, and tortuous types. The ICA–OA angle defined by the angle between the approximate line of the proximal OA and the vertical line was also variable. The first bend of the OA corresponded to the anastomosis site with the external carotid system. The proximal medial bend was the origin of the posterior ethmoidal artery, and the distal medial bend was the origin of the anterior ethmoidal artery.

Conclusions

According to the results the OA not only possesses three characteristic bends, but also shows prominent individual variability and commonly shows bilateral asymmetry. The contour of the OA may be regulated by the anchor effect at the bend sites. PC MR Angiography is useful for visualizing the main trunk of the OA.     

Complex anomalies of type 1 proatlantal intersegmental artery and aortic arch variations

Purpose

We report a case of type 1 proatlantal intersegmental artery (PIA) associated with multiple anomalies of the aortic arch, and discuss the possible embryonic mechanism and clinical importance of the multiple cerebrovascular variants in this patient.

Methods

A 65-year-old woman with dizziness underwent cerebral magnetic resonance (MR) imaging and head and neck MR angiography using a 3-tesla scanner and computed tomography (CT) angiography using a 64-slice multidetector CT scanner.

Results

MR and CT angiography demonstrated an aneurysm of the distal end of the azygos anterior cerebral arteries and hypoplasia of the proximal right vertebral artery (VA) with an anastomotic artery, between the right internal carotid artery (ICA) and distal right VA that passed through the foramen magnum, indicating a type 1 PIA. She also demonstrated an aberrant right subclavian artery (ARSA) with hypoplasia of the right VA, and the left VA arose directly from the aortic arch.

Conclusion

To our knowledge, this is the first report of a type 1 PIA associated with multiple vascular anomalies of the aortic arch, such as ARSA and origin of the left VA from the arch. In cases of persistent anastomoses between the carotid and vertebrobasilar arteries, such as PIAs, imaging examination should include the aortic arch to identify associated vascular variations.     

Correction of cerebral ischemia in low-resistant animals with an antistress drug Deltaran

Deltaran decreased the amplitude of EEG slow waves and restored neuronal reactivity after carotid artery occlusion in Wistar rats sensitive to cerebral ischemia. Deltaran had no effect on local cerebral blood flow. This drug increased blood supply to a unit of neuronal activity in the brain of intact animals during the acute stage of cerebral ischemia, provided 100% survival rate of rats with cerebral ischemia, and prevented the development of neurological symptoms in survivors. Animal experiments proved the possibility of correcting cerebral ischemia with antistress drug Deltaran. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 3, pp. 259–262, March, 2006     

Prevention of both T2- and diffusion-weighted increases in image intensity during cerebral hypoxia-ischemia in infant rats pretreated with dexamethasone

 The present study examines the effect of dexamethasone treatment on the intensity of changes in T₂-weighted and diffusion-weighted (DW) magnetic resonance images occurring in infant rats during and after cerebral hypoxia-ischemia. The right carotid artery was occluded under isoflurane anesthesia in 7-day-old rats and images were acquired in sedated animals using a Bruker 9.4 T magnetic resonance (MR) system. Imaging changes were markedly different in rats pretreated with dexamethasone phosphate (0.1 mg/kg, i.p.) 24 h before hypoxia than in controls. In control animals, areas of hyperintensity ipsilateral to the occlusion occurred during hypoxia-ischemia in both the DW- and T₂-weighted images with some recovery of the changes in early posthypoxia. In contrast, in dexamethasone-treated animals, areas of increased hyperintensity in the MR images did not occur. Thus, dexamethasone treatment prevents MR imaging changes during ischemia, suggesting that the cytotoxic edema associated with energy depletion and/or ionic disturbances during ischemia are also prevented by dexamethasone treatment. Received: 31 March 1998 / Accepted: 1 December 1998     

缺血后适应对树鼩海马CA1区脑血流及星形胶质细胞活化的影响及可能机制

目的：研究缺血后适应（PC）对树鼩局部脑缺血海马CA1区脑血流（rCBF）与星形胶质细胞（AS）活化的影响，探讨缺血PC影响AS表达胶质纤维酸蛋白（GFAP)的可能机制。方法：建立树鼩血栓性局部脑缺血及缺血PC模型，通过激光多普勒（LD）血流计测量脑缺血后4 h、8 h、12 h、24 h及72 h海马CA1区rCBF的改变；用免疫组化法测定脑缺血上述时间海马GFAP的表达，并用图像分析系统测定其平均灰度值。于脑缺血后4 h重复3次夹闭缺血侧颈总动脉实施缺血PC，并观察其对海马CA1区rCBF和AS活化以及GFAP表达的影响。结果：树鼩脑缺血后4h海马CA1区GFAP阳性细胞数增多，AS表达GFAP增强，24h可见AS胀亡；72h海马CA1区AS表达GFAP达高峰（120.0±2.1，P＜0.01）。脑缺血时海马CA1区rCBF逐渐降低，以24 h的改变最显著,为(2.55±0.28) PU，P＜0.01；72 h时海马CA1区rCBF略有增加，为(9.84±1.22) PU。实施缺血PC后，海马CA1区rCBF逐渐增加，72 h最显著,为(18.74±1.60) PU，P＜0.01；此时海马GFAP表达进一步增强（111.0±1.3),P＜0.01。但AS胀亡的病理改变基本消失。结论：多次短暂的闭塞动物的颈动脉可延长树鼩脑缺血治疗的“时间窗”；缺血PC的脑保护机制可能与增加海马rCBF、调控AS活化及改善海马微环境有关。     

Risk factor–gene interaction in carotid atherosclerosis: effect of gene polymorphisms of renin-angiotensin system

The risk factor–gene interaction in carotid atherosclerosis was investigated in 205 community-dwelling healthy subjects aged 50 years or more in Japan. The intima–media thickness (IMT) of the common carotid artery was evaluated by ultrasonography with a 7.5-MHz probe. Gene polymorphisms were determined for each subject with angiotensin-converting enzyme (ACE) insertion/deletion (I/D), angiotensinogen (AGT) M235T, angiotensin II type 1 receptor (AT1R) A1166C, and apolipoprotein E (apoE) genotypes. There was no genotype-specific difference in carotid IMT among any genes examined. Combinations of genotypes did not increase carotid IMT compared with subjects without these genotypes. In the total population, multiple regression analysis showed that age, systolic blood pressure (SBP), sex, and body mass index (BMI) were significantly associated with carotid IMT. However, the association between risk factors and IMT was genotype-specific. Age was significantly associated with IMT in ACE D carriers, but not in subjects with the ACE II genotype. Analysis of covariance adjusted with other risk factors showed that the age-dependent change in IMT was significantly different between subjects with the ACE II genotype and the ACE D carriers (F[1.196] = 4.97; P = 0.027). Similarly, the regression of IMT on SBP was significantly different between AGT TT and AGT MT + MM (F[1.196] = 7.20; P = 0.0079). The regression of IMT on BMI was also significantly different between apo E4 carriers and noncarriers (F[1.196] = 6.78; P = 0.0099). Furthermore, general linear model analysis with risk factors, genotype, and risk factor-genotype interactions revealed that the age^*ACE genotype interaction, the SBP^*AGT genotype interaction, and the BMI^*apoE genotype interaction were significantly associated with IMT. These findings further support the role of risk factor-gene interaction in carotid atherosclerosis. Received: January 5, 2001 / Accepted: February 5, 2001     

Noopept Reduces the Postischemic Functional and Metabolic Disorders in the Brain of Rats with Different Sensitivity to Hypoxia

Chronic cerebral ischemia was induced by ligation of both common carotid arteries in Wistar rats, divided by sensitivity to hypoxia into highly sensitive and low-sensitive. Noopept (peptide preparation), injected (0.5 mg/kg) during 7 days after occlusion of the carotid arteries, reduced the neurological disorders in rats with high and low sensitivity to hypoxia and improved their survival during the postischemic period. Noopept normalized behavior disordered by cerebral ischemia (according to the open field and elevated plus maze tests), prevented accumulation of LPO products and inhibition of antioxidant systems in the brain of rats with high and low sensitivity to hypoxia. Hence, noopept exhibited a neuroprotective effect in cerebral ischemia. Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 147, No. 3, pp. 311–316, March, 2009     

缺血后适应促进树鼩血栓性脑缺血时紧密连接occludin/ZO-1蛋白表达及抑制脑水肿的机制

 目的: 研究脑缺血及缺血后适应(postconditioning,PC)条件下,树鼩脑缺血时局部脑血流(regional cerebral blood flow,rCBF)、脑水肿及紧密连接(tight junction,TJ)的occludin和zonula occludins(ZO)-1蛋白表达的改变;探讨TJ表达对脑水肿及脑梗死的影响及其可能机制。方法: 将72只健康成年树鼩随机分为对照组、脑缺血组和脑缺血+PC组,其余3只动物用于磁共振成像(MRI)观察。通过光化学反应诱导树鼩局部血栓形成;缺血PC组于缺血后4 h夹闭患侧颈总动脉3次(每次5 min)实施PC处理。用电镜观察神经超微结构,用TUNEL法检测海马神经元的凋亡数量,用激光多普勒血流监测仪检测缺血区的rCBF,用免疫组化及Western blot法观察缺血海马occludin/ZO-1蛋白的表达,MRI技术监测脑梗死体积,组织干湿法检测脑含水量的改变。结果: 树鼩脑缺血后海马CA1区的正常神经元明显减少以及神经元超微结构明显异常。脑缺血组TUNEL阳性细胞数明显增加(P<0.01),rCBF明显降低,occludin/ZO-1表达减弱(P<0.01),脑含水量和脑梗死体积明显增加(P<0.01)。经PC处理的动物,缺血区rCBF增加,TJ表达增强,脑含水量降低,且TUNEL阳性细胞数和脑梗死体积明显减小(P<0.01)。结论: 缺血PC可增加树鼩缺血区rCBF但不增加局部含水量;提示缺血PC缩小脑梗死体积可能与occludin/ZO-1表达增强而抑制脑水肿有关。