Brain structural changes and their correlation with vascular disease in type 2 diabetes mellitus patients: a voxel-based morphometric study

Voxel-based morphometry has been used in the study of alterations in brain structure in type 1 diabetes mellitus patients. These changes are associated with clinical indices. The age at onset, pathogenesis, and treatment of type 1 diabetes mellitus are different from those for type 2 diabetes mellitus. Thus, type 1 and type 2 diabetes mellitus may have different impacts on brain structure. Only a few studies of the alterations in brain structure in type 2 diabetes mellitus patients using voxel-based morphometry have been conducted, with inconsistent results. We detected subtle changes in the brain structure of 23 cases of type 2 diabetes mellitus, and demonstrated that there was no significant difference between the total volume of gray and white matter of the brain of type 2 diabetes mellitus patients and that in controls. Regional atrophy of gray matter mainly occurred in the right temporal and left occipital cortex, while regional atrophy of white matter involved the right temporal lobe and the right cerebellar hemisphere. The ankle-brachial index in patients with type 2 diabetes mellitus strongly correlated with the volume of brain regions in the default mode network. The ankle-brachial index, followed by the level of glycosylated hemoglobin, most strongly correlated with the volume of gray matter in the right temporal lobe. These data suggest that voxel-based morphometry could detect small structural changes in patients with type 2 diabetes mellitus. Early macrovascular atherosclerosis may play a crucial role in subtle brain atro- phy in type 2 diabetes mellitus patients, with chronic hyperglycemia playing a lesser role.

Therapeutic effect of nerve growth factor on cerebral infarction in dogs using the hemisphere anomalous volume ratio of diffusion-weighted magnetic resonance imaging

A model of focal cerebral ischemic infarction was established in dogs through middle cerebral artery occlusion of the right side.Thirty minutes after occlusion,models were injected with nerve growth factor adjacent to the infarct locus.The therapeutic effect of nerve growth factor against cerebral infarction was assessed using the hemisphere anomalous volume ratio,a quantitative index of diffusion-weighted MRI.At 6 hours,24 hours,7 days and 3 months after modeling,the hemisphere anomalous volume ratio was significantly reduced after treatment with nerve growth factor. Hematoxylin-eosin staining,immunohistochemistry,electron microscopy and neurological function scores showed that infarct defects were slightly reduced and neurological function significantly improved after nerve growth factor treatment.This result was consistent with diffusion-weighted MRI measurements.Experimental findings indicate that nerve growth factor can protect against cerebral infarction,and that the hemisphere anomalous volume ratio of diffusion-weighted MRI can be used to evaluate the therapeutic effect.

Scanning pattern of diffusion tensor tractography and an analysis of the morphology and function of spinal nerve roots

Radiculopathy, commonly induced by intervertebral disk bulging or protrusion, is presently diag- nosed in accordance with clinical symptoms because there is no objective quantitative diagnostic criterion. Diffusion tensor magnetic resonance imaging and diffusion tensor tractography revealed the characterization of anisotropic diffusion and displayed the anatomic form of nerve root fibers. This study included 18 cases with intervertebral disc degeneration-induced unilateral radiculopathy. Magnetic resonance diffusion tensor imaging was creatively used to reveal the scanning pattern of fiber tracking of the spinal nerve root. A scoring system of nerve root morphology was used to quantitatively assess nerve root morphology and functional alteration after intervertebral disc de- generation. Results showed that after fiber tracking, compared with unaffected nerve root, fiber bundles gathered together and interrupted at the affected side. No significant alteration was de- tected in the number of fiber bundles, but the cross-sectional area of nerve root fibers was reduced. These results suggest that diffusion tensor magnetic resonance imaging-based tractography can be used to quantitatively evaluate nerve root function according to the area and morphology of fiber bundles of nerve roots.

Quantitative analysis of intraspinal cerebrospinal fluid flow in normal adults

The present study quantitatively analyzed intraspinal cerebrospinal fluid flow patterns in 19 normal adults using fast cine phase-contrast magnetic resonance imaging. Results showed increased downward flow velocity and volume compared with upward flow, and the average downward flow volume of intraspinal cerebrospinal fluid decreased from top to bottom at different intervertebral disc levels. Upward and downward cerebrospinal fluid flow velocity reached a peak at the thoracic intraspinal anterior region, and velocity reached a minimum at the posterior region. Overall measurements revealed that mean upward and downward flow volume positively correlated with the subarachnoid area. Upward peak flow velocity and volume positively correlated with spinal anteroposterior diameter. However, downward peak flow velocity and volume exhibited a negative correlation with spinal anteroposterior diameter. Further flow measurements showed that flow velocity in upward and downward directions was associated with subarachnoid anteroposterior diameter, respectively. The present experimental results showed that cerebrospinal fluid flow velocity and volume varied at different intraspinal regions and were affected by subarachnoid space area and anteroposterior diameter size.

Effects of nerve growth factor on the expression of caspase-12 of nerve cells in cerebral ischemia/reperfusion area

BACKGROUND： Researches suggest that cascade reaction of cysteine protease mediated by caspase-12 can cause apoptosis after cerebral ischemia/reperfusion injury; however, nerve growth factor （NGF） can reduce apoptosis through inhibiting activation of that reaction. OBJECTIVE： To observe the effect of NGF on the expression of caspase-12 in brain tissue of rabbits with cerebral ischemia/reperfusion injury, and elucidate the protective mechanism of NGF on neural apoptosis induced by cerebral ischemia/reperfusion injury. DESIGN： Randomized controlled animal study SETTING： Department of Image, Second Hospital, Hebei Medical University .MATERIALS ： A total of 26 healthy New Zealand rabbits, of clean grade, aged 4.5-5 months, weighing （2.6±0.2） kg, were selected in this study. Reagents： NGF （Xiamen Beida Zhilu Biotechnology Co., Ltd.）; caspase-12 （Santa Cruz Biotechnology Company, USA, clone number： SC-12395）; caspase-3 （Santa Cruz Biotechnology Company, USA, clone number： SC-7272）; biotin-antibody Ⅱ and ABC compound （Wuhan Boster Company）; in situ end-labeling （ISEL, Beijing Zhongshan Company）. METHODS： The experiment was carried out in the Laboratories of Nerve Molecule Image Science and Neurology of the Second Hospital of Hebei Medical University from May to August 2005. （1） All animals were randomly divided into three groups. Ischemia/reperfusion （I/R） group （n=10）： Left middle cerebral artery （MCA） was blocked for 2 hours and then blooded for 2 hours in order to establish focal cerebral ischemi- a/reperfusion models. Sham operation group （n=6）： Cork was inserted with 3 cm in depth, and then pulled to common carotid artery. Other procedures were as the same as those in ischemia/reperfusion group. Treatment group （n=-10）： After modeling, 400 AU （16 μg/L） NGF was inserted into cerebral infarction focus immediately. （2） Brain tissue was taken out from left ischemia/reperfusion area at 3 days after operation in sham operation group and at 3 days after reperfusion in other two groups, In addition, contents of caspase-12 and caspase-3 were measured with immunohistochemical technique; mean absorbency （A value） was compared with image analytic system; apoptosis rate and apoptosis quantity of nerves in ischemia/reperfusion area were detected with flow cytometry and DNA TdT-mediated biotinylated-dUTP nick end labeling method. （3） Measurement data were compared with one-way analysis of variance among groups and with q test every two groups. MAIN OUTCOME MEASURES： Expressions of caspase-12 and caspase-3 and apoptosis in cerebral ischemia/reperfusion area in the 3 groups. RESULTS： All 26 rabbits were involved in the final analysis. （1） Expressions of caspase-12 and caspase-3： Expression of caspase-12 was 0.36±0.02 in I/R group and 0.13±0.03 in treatment group; expression of caspase-3 was 0.49±0.05 and 0.27±0.06, respectively. Both of them were higher than those in sham operation group （0.07±0.02, 0.09±0.03, P 〈 0.01）, and expressions of two proteases were lower in treatment group than those in I/R group （P 〈 0.01）. There were significant differences of expression of caspase between I/R group and treatment group as compared with that in sham operation group; meanwhile, there were significant differences between treatment group and I/R group. （2） Apoptosis： Apoptosis rate was （20.2±1.3）% in I/R group and （7.7±0.8）% in treatment group; apoptosis quantity was （32.8±2.6）, （7.6±1.5） /high sight, respectively, Both of them were higher and more than those in sham operation group [（4.8 ±0.4）%, （0.7±0.2） /high sight, P 〈 0.01]. Apoptosis rate and apoptosis quantity were lower and less in treatment group than those in I/R group （P 〈 0.01）. There was significant difference between I/R group and treatment group as compared with sham operation group, and there was significant difference between treatment group and I/R group. CONCLUSION： NGF can decrease the number of apoptotic cells of the cerebral ischemia/reperfusion and inhibit the caspase cascade reaction induced by caspase-12, which is one of the protective mechanisms of NGF.

中华鬣羚行为谱及PAE编码系统的建立

栖息地破碎化、人为干扰等因素影响着中华鬣羚(Capricornis sumatraensis)的生存。目前,中华鬣羚的行为研究还比较匮乏,因此有必要构建中华鬣羚的行为谱及PAE(posture-act-environment)编码系统,以期促进其基础行为资料的完善,为深入开展科学研究和保护工作奠定基础。本文旨在:(1)参照国内常用的动物行为编码方法,以"姿势–动作–环境"为轴心,建立中华鬣羚的行为谱及PAE编码系统,并随机抽取20%的中华鬣羚视频作为检测样本,对行为谱的实际使用效果进行测试。(2)对中华鬣羚的行为数据进行统计并通过计算行为多样性指数,分析各特定年龄组间的行为多样性差异,检验特定年龄组与行为多样性指数间的相关性。结果显示:(1)通过区别和归类中华鬣羚的10种姿势、80种动作、9种环境、78种行为,首次建立了中华鬣羚的行为谱及PAE编码系统。经测试,该行为谱能够客观地对中华鬣羚行为进行识别和归类。(2)与亚成体和幼体相比,中华鬣羚成体特定行为类型的行为多样性指数(A;)、绝对行为多样性指数(A)、相对行为多样性指数(r)和校正行为多样性指数(r-variable)均为最高;中华鬣羚亚成体特定行为类型的行为多样性指数(A;)、绝对行为多样性指数(A)、相对行为多样性指数(r)介于成体和幼体之间;中华鬣羚幼体的特定行为类型的行为多样性指数(A;)、绝对行为多样性指数(A)和相对行为多样性指数(r)最低,校正行为多样性指数(r-variable)高于亚成体。(3)中华鬣羚行为谱可用于其行为学研究,今后应获取繁殖行为的图像数据,更新行为谱及PAE编码系统。(4)3个特定年龄组中华鬣羚的各行为多样性指数之间差异不显著(F=0.013, P=0.987),从幼体到成体,中华鬣羚的特定行为类型的行为多样性指数(A;)、绝对行为多样性指数(A)和相对行为多样性指数(r)随年龄的增大呈递增趋势。综上所述,我们应深入研究中华鬣羚行为学,为其保护工作提供科学支撑。