皮质脑干纤维终末的超微结构——溃变电镜法研究

用溃变电镜法观察了１２只大鼠的中缝大核，蓝斑，旁正中网状核，巨细胞状核，桥核，外侧网状核和下橄榄主核中皮质下行纤维终末的溃变型，超微结构及突触联系。结果如下：（１）皮质纤维有三种溃变型，即电子致密型，微丝增生型和电子透明型。以电子致突型为主。（２）三种溃变型在各核中出现的数量和种类不同。（３）电子致密型溃变终扣有含圆形清亮型小泡，多形清亮型小泡和混合型小泡三种终扣。各核中，三种不同小泡终扣的出现种     

杏仁核与纹状体边缘区的功能和纤维联系

目的：研究杏仁核和纹状体边缘区的功能和纤维联系。方法：用神经功能活动形态定位方法，将低浓度的海人藻酸注射到杏仁核作为化学刺激剂，观察注射后原癌基因蛋白C-Fos在脑内的表达；用免疫组化的方法观察P物质在边缘区及杏仁核等脑区的分布。结果：C-Fos在海马、终纹床核、Meynert基核、边缘区及皮层有强表达。P物质的边缘区呈带状分布，其阳性纤维在背侧与终纹床核相连，在腹侧延续至杏仁核。结论：杏仁核与纹状体边缘区存在功能和纤维联系。     

Response characteristics of cerebellar interpositus and intermediate cortex neurons to sinusoidal stimulation of neck and labyrinth receptors

The response characteristics of neurons located in the interpositus nucleus and the intermediate cortex of the cerebellar anterior lobe to sinusoidal rotation of the cervical axis vertebra along the longitudinal axis of the animal, while the head of the animal remained stationary in the horizontal plane, have been examined in precollicular decerebrate cats. A large proportion of interpositus (58.3%) and corticocerebellar units (65.4%) showed a periodic modulation of the firing rate in response to sinusoidal stimulation of neck receptors. The majority of these neurons (78.6%) responded to the angular stimulation in phase with the peak displacement. Most of these positional sensitive units (63.6%) were excited during side-down rotation of the neck and inhibited during side-up rotation, while the remaining units (36.4%) showed the opposite behavior. Within the range of stimulation used the neck afferent system was relatively linear, i.e. the sensitivity of the response, expressed as a percentage change of the average discharge rate per degree of displacement, was only slightly affected by changing the amplitude of neck rotation. Moreover, neither the sensitivity nor the phase angle of the responses were greatly modified by changing frequency of neck rotation. A smaller proportion of interpositus (21.8%) and corticocerebellar units (34.8%) showed a periodic modulation of the discharge rate in response to sinusoidal rotation along the longitudinal axis of the whole animal, leading to stimulation of labyrinth receptors. Two-thirds of these units responded to changes in animal position, due to stimulation of macular receptors. In most of the positional sensitive units (70%), the firing rate decreased during side-down rotation of the animal and increased during side-up rotation, while the remaining units (30%) showed the opposite behavior.These findings indicate that the neck input of one side, elicited during side-down rotation of the neck, exerts a prominent excitatory influence on the ipsilateral intermediate zone of the cerebellum, whereas the macular input of one side, activated during side-down rotation of the animal, exerts a prominent excitatory influence on the contralateral intermediate zone. The macular input was, however, considerably weaker than the neck input.Neurons of the intermediate zone of the cerebellum also received bilateral convergent signals from the fore- and hindlimbs.It is concluded that changes in neck or head position may modify the background discharge of both the fore- and hindlimb regions of the interpositus nucleus and the intermediate cortex, thus affecting the activity of flexor motoneurons during the tonic neck and labyrinth reflexes. In addition, the neck input may modify the response of the intermediate corticonuclear zone of the cerebellum to cutaneous afferent volleys originating from the ipsilateral fore- and hindlimb, for instance during the placing reaction, thus affecting the magnitude of the flexor response underlying this long-loop reflex.     

Health Benefits of Fiber Fermentation

Although fiber is well recognized for its effect on laxation, increasing evidence supports the role of fiber in the prevention and treatment of chronic disease. The aim of this review is to provide an overview of the health benefits of fiber and its fermentation, and describe how the products of fermentation may influence disease risk and treatment. Higher fiber intakes are associated with decreased risk of cardiovascular disease, type 2 diabetes, and some forms of cancer. Fiber may also have a role in lowering blood pressure and in preventing obesity by limiting weight gain. Fiber is effective in managing blood glucose in type 2 diabetes, useful for weight loss, and may provide therapeutic adjunctive roles in kidney and liver disease. In addition, higher fiber diets are not contraindicated in inflammatory bowel disease or irritable bowel syndrome and may provide some benefit. Common to the associations with disease reduction is fermentation of fiber and its potential to modulate microbiota and its activities and inflammation, specifically the production of anti-inflammatory short chain fatty acids, primarily from saccharolytic fermentation, versus the deleterious products of proteolytic activity. Because fiber intake is inversely associated with all-cause mortality, mechanisms by which fiber may reduce chronic disease risk and provide therapeutic benefit to those with chronic disease need further elucidation and large, randomized controlled trials are needed to confirm causality.Teaching Points? Strong evidence supports the association between higher fiber diets and reduced risk of cardiovascular disease, type 2 diabetes, and some forms of cancer.? Higher fiber intakes are associated with lower body weight and body mass index, and some types of fiber may facilitate weight loss.? Fiber is recommended as an adjunctive medical nutritional therapy for type 2 diabetes, chronic kidney disease, and certain liver diseases.? Fermentation and the resulting shifts in microbiota composition and its activity may be a common means by which fiber impacts disease risk and management.     

磁共振弥散张量纤维束示踪成像在脑肿瘤手术中的应用

目的:探讨弥散张量纤维束成像(diffusion tensor tractography,DTT)其在脑肿瘤中的应用价值.方法:对83例脑肿瘤行常规MRI及DTT检查,通过获取部分各向异性图(FA图)、彩色编码张量图及脑白质纤维束图,依次分析83患者肿瘤与瘤周白质纤维束之间的关系.测量83脑肿瘤患者肿瘤实质区、瘤周水肿区、邻近白质区及对侧正常白质区的ADC值、FA值.结果:ADC值在肿瘤实质区,瘤周水肿区,邻近白质区中,低级别胶质瘤与高级别胶质瘤具有差异性,而在正常白质区差异不具有统计学意;FA值在肿瘤实质区,低级别胶质瘤与高级别胶质瘤具有差异性,而在瘤周水肿区,邻近白质区中,正常白质区差异不具有统计学意义.且83例良、恶性肿瘤瘤周白质纤维束都可以发生移位;瘤周水肿区白质纤维束表现为浸润和破坏为主,其破坏程度与肿瘤的恶性程度呈正比.结论:DTT可直观显示脑白质损伤程度并观察神经纤维束受损范围.