4、5、7-三羟异黄酮对大鼠颌骨缺损愈合的影响

目的 通过建立大鼠的下颌骨缺损模型,研究4、5、7-三羟异黄酮对大鼠颌骨缺损愈合的作用.方法 建立SD大鼠单侧下颌骨颊舌向贯穿的骨缺损模型,分为骨缺损用药组与骨缺损组,每组30只,骨缺损用药组术后每天注射4、5、7-三羟异黄酮.分别于给药后7、14、28天检测血清骨碱性磷酸酶(B-ALP)、Ⅰ型前胶原羧基端肽(PICP)、骨钙素(BGP)的生化指标,并各处死10只大鼠取下颌骨,进行X线摄片分析、组织学染色观察.结果 相同时间点,骨缺损用药组B-ALP、PICP、BGP的水平显著降低;骨缺损用药组大鼠下颌骨缺损区的X线平均灰度值明显高于骨缺损组.组织学观察,骨缺损组缺损区愈合明显延迟于骨缺损用药组.结论 4、5、7-三羟异黄酮可调节颌骨代谢,促进大鼠颌骨缺损的愈合.     

Excitatory amino acid receptors in the periaqueductal gray mediate the cardiovascular response evoked by activation of dorsomedial hypothalamic neurons

Neurons in the region of dorsomedial hypothalamus are involved in the organization of the physiological responses to emotional stress. We have recently shown that the cardiovascular response evoked by activation of dorsomedial hypothalamus neurons is largely dependent on a synaptic relay with the lateral/dorsolateral periaqueductal gray region. In this study, we aimed to investigate whether excitatory amino acid receptors at the lateral/dorsolateral periaqueductal gray region are involved in mediating the response evoked by activation of dorsomedial hypothalamus neurons. In conscious rats, the cardiovascular effects produced by microinjection of GABA(A) receptor antagonist, bicuculline methiodide into the dorsomedial hypothalamus were evaluated before and after injection of different excitatory amino acid antagonists into lateral/dorsolateral periaqueductal gray region. Pretreatment of lateral/dorsolateral periaqueductal gray region with the non-selective ionotropic excitatory amino acid receptor antagonist kynurenic acid or with the N-methyl-D-aspartate receptor-selective antagonist, MK-801, largely reduced the tachycardic and pressor effects evoked by activation of dorsomedial hypothalamus neurons by bicuculline methiodide microinjection (heart rate 90 and 74%; blood pressure 81 and 84%, respectively). The non-N-methyl-D-aspartate receptor-selective antagonist 6-cyano-7-nitroquinoxaline-2,3-dione, did not alter the cardiovascular response evoked by dorsomedial hypothalamus activation. In an additional series of experiments, microinjection of the N-methyl-D-aspartate receptor agonist, N-methyl-D-aspartate, into the lateral/dorsolateral periaqueductal gray region, evoked an increase in heart rate and a pressor response that was accompanied by an increase in locomotor activity. These effects were not altered by pretreatment of lateral/dorsolateral periaqueductal gray region neurons with 6-cyano-7-nitroquinoxaline-2,3-dione but were completely abolished by MK-801. Altogether, these findings indicate that the cardiovascular response evoked by dorsomedial hypothalamus activation involves a synaptic relay at the lateral/dorsolateral periaqueductal gray region that is mediated at least in large part by excitatory amino acid receptors, possibly N-methyl-D-aspartate receptors.     

Clinical implications of headache in lacunar stroke: relevance of site of infarct

OBJECTIVE: To assess whether the infarction topography influenced upon the incidence of headache and the likelihood of neurological recovery in lacunar infarction. BACKGROUND: The relationship between topography of infarction and the incidence of headache as well as the influence of headache on neurological outcome in patients with lacunar stroke are still unclear. METHODS: In a cohort of 387 patients with neuroimaging-proven acute lacunar infarction collected from a prospective hospital-based stroke registry over a 12-year period, 43 patients (11.1%) presented with headache within a 72-hour interval of stroke onset. RESULTS: Headache was more common in deep brain gray matter or brainstem lacunar infarction than in supratentorial white matter lacunar infarction (14.9% vs 8%, P < .033), but lacunar infarctions in the supratentorial white matter had less frequently absence of limitation at discharge (15.1% vs 25.1%, P < .013). In deep brain gray matter or brainstem lacunar infarction, early neurological recovery decreased from 26.2% to 19.2% when headache was present at stroke onset. In the multivariate analysis, dysarthria-clumsy hand and absence of headache in deep brain gray matter or brainstem lacunar infarction were independent predictors of favorable outcome. CONCLUSIONS: In patients with lacunar infarction, headache at stroke onset was more common in deep brain gray matter or brainstem topographies than in supratentorial white matter lesions. In deep brain gray matter or brainstem lacunar infarctions, early neurological recovery was less likely when headache was present.     

Estrogen alters c-Fos response to immobilization stress in the brain of ovariectomized rats

Estrogen receptors are widely expressed in the brain, where estrogen modulates central nervous function. In this study, we investigated the effect of estrogen on the emotional stress response in the brain by comparing the CNS patterns of c-Fos expression in response to immobilization stress (IMO) in ovariectomized rats with placebo treatment (OVX + Pla) vs. ovariectomized rats supplemented with 17beta-estradiol (OVX + E2). Increased c-Fos immunoreactive neurons in response to IMO were observed in cerebral cortex, septum, thalamus, hypothalamus, midbrain, pons and medulla oblongata in accordance with previous findings. When OVX + E2/Stress were compared with OVX + Pla/Stress, the numbers of c-Fos immunoreactive cells were significantly lower in the lateral septum, paraventricular hypothalamic nucleus, dorsomedial hypothalamic nucleus, medial amygdaloid nucleus, lateral periaqueductal gray, laterodorsal tegmental nucleus and locus coeruleus, while they were significantly higher in paraventricular thalamic nucleus and nucleus of the solitary tract. These data suggest that neuronal activities in these areas are influenced bidirectionally by systemic estrogen level.     

A short-chain α-neurotoxin from Naja naja atra produces potent cholinergic-dependent analgesia

Objective To investigate the analgesia induced by cobrotoxin （CT） from venom of Naja naja atra, and the effects of atropine and naloxone on the antinociceptive activity of CT in rodent pain models. Methods CT was administered intraperitoneally （33.3, 50, 75 μg/kg）, intra-cerebral venticularly （2.4 μg/kg） or microinjected into periaqueductal gray （PAG, 1.2 μg/kg）. The antinociceptive action was tested using the hot-plate test and the acetic acid writhing test in mice and rats. The involvement of cholinergic system and the opioid system in CT-induced analgesia was examined by pretreatment of animals with atropine （0.5 mg/kg, im or 10 mg/kg, ip） or naloxone （3 mg/kg, ip）. The effect of CT on motor activity was tested using the Animex test. Results CT （33.3, 50 and 75 μg/kg, ip） exhibited a dosedependent analgesic action in mice as determined with hot-plate test and acetic acid writhing test. In the mouse acetic acid writhing test, the intra-cerebral ventricle administration of CT 2.4 μg/kg （1/23th of a systemic dose） produced marked analgesic effects. Microinjection of CT 1.2 μg/kg （1/46th of systemic dose） into the PAG also elicited a robust analgesic action in the hot-plate test in rats. Atropine at 0.5 mg/kg （ira） or naloxone at 3 mg/kg （ip） failed to block the analgesic effects of CT, but atropine at 10 mg/kg （ip） did antagonize the analgesia mediated by CT in the mouse acetic acid writhing test. At the highest effective dose of antinociception （75 μg/kg）, CT did not change the spontaneous mobility of mice. Conclusion These results suggest that CT from Naja naja atra venom has analgesic effects. Central nervous system may be involved in CT＇ analgesic effects and the PAG may be the primary central site where CT exerts its effects. The central cholinergic system but not opioid system appears to be involved in the antinociceptive action of CT.     

脑灰质异位症MRI诊断

目的探讨脑灰质异位症(GMH)的MR I诊断及鉴别诊断。方法10例GMH患者均行MR回波序列扫描,其中男7例,女3例,年龄7~32岁,平均15岁。1例行MR增强扫描。结果10例共发现病灶14个,分为3种类型:室管膜下型5例、皮质下型3例、带状型2例。表现为侧脑室旁或白质区内的结节状或不规则状团块影,与大脑皮层灰质及灰质核团信号一致,单发7例、多发3例,单侧发病8例,双侧发病2例,大小1~5 cm不等,无水肿及占位效应,2例带状型灰质异位对称分布于皮层灰质与侧脑室间,内外均有白质带,与灰质信号一致。结论GMH的MR I表现具有特异性。     

Cognitive correlates of brain MRI subcortical signal hyperintensities in non-demented elderly

OBJECTIVE: To investigate the relationship between magnetic resonance imaging (MRI) subcortical gray and capsular (SGCH) and white matter hyperintensities (WMH) and cognitive functions in non-demented community dwelling elderly. METHODS: The severity of SGCH and WMH on proton density and T2 MR images in 16 subjects was scored using the semi-quantitative rating scale of Scheltens et al. (1993). A limited series of cognitive tests selected a priori were then correlated with severity of SGCH and WMH. RESULTS: Analysis demonstrated that severity of SGCH was inversely related to performance on the Digit Span (R = -0.64, p < 0.01) and the Stroop Color Word Tests (R = -0.64, p < 0.01). Severity of WMH was related to worsening performance on the Trail Making Test (R = 0.67, p < 0.005). CONCLUSIONS: These findings indicate that severity of WMH is negatively related to more pure executive cognitive functions, specifically set shifting, while severity of SGCH is inversely related to more basic functions of attention and working memory.     

Gray matter volume covariance networks associated with dual‐task cost during walking‐while‐talking

We studied gray matter volume covariance networks associated with normal pace walking (NPW) speed and dual‐task costs (DTCs) during walking‐while‐talking (WWT)—a mobility stress test that involves walking while reciting alternate letters of the alphabet. Using a multivariate covariance‐based analytic approach, we identified gray matter networks associated with NPW speed (mean 102.1 cm/s ±22.5 cm/s) and DTC (percent difference in gait speed between NPW and WWT, mean 25.9% ± 18.8%) in 139 older adults without dementia (M = 75.3 ± 6.1 years). The gray matter network associated with NPW was primarily composed of supplementary motor area, precuneus cortex, and the middle frontal gyrus. Greater expression of this NPW network was associated with better processing speed (trail‐making test A [r = ?0.30, p = 0.005]) and executive function (trail‐making test B ? A [r = ?0.43, p < 0.0001]). The gray matter network associated with DTC was primarily composed of medial prefrontal, cingulate, and thalamic regions. Greater expression of this DTC network was associated with better episodic memory performance on the free and cued selective reminding test (r = 0.30, p = 0.007). These results suggest that NPW speed and DTC are supported by different networks, and are associated with different cognitive domains.     

Automated brain tissue and myelin volumetry based on quantitative MR imaging with various in-plane resolutions

Background and purpose

Segmented brain tissue and myelin volumes can now be automatically calculated using dedicated software (SyMRI), which is based on quantification of R₁ and R₂ relaxation rates and proton density. The aim of this study was to determine the validity of SyMRI brain tissue and myelin volumetry using various in-plane resolutions.