Immunohistochemical and immunoelectron microscopical characterization of cerebrovascular and senile plaque amyloid in aged dogs'' brains

Immunohistochemical and immunoelectron microscopical studies were carried out on 28 aged dogs' brains. Amyloid deposits were seen in the arteries and capillaries in the leptomeninges and in superficial areas of the cortices in 19 (67.9%) of the 28 dogs (10-22 years of age). Immunohistochemically, these amyloid deposits were reactive for anti-beta/A4 antibody. Additionally, a variable number of parenchymal deposits with diffuse beta/A4-immunoreactivity (diffuse plaques) was also noted throughout the cerebral cortex in 24/28 dogs (85.7%). However, these plaque lesions were undetectable in Congo red staining. Electron microscopically, amyloid fibrils, measuring 10 nm in width, were located mainly in the tunica media of the arteries, and in less involved vessels they tended to be present among collagen fibres in the adventitia and smooth muscle cells in the outer layer of the media. The plaque lesions appeared to contain sparse aggregations of amyloid fibrils. In immunoelectron microscopical examinations, all amyloid fibrils in both blood vessels and plaques were selectively labelled by gold particles. These findings indicate that aged dogs can provide a useful experimental model for research into the beta/A4-type of cerebral amyloidosis commonly seen in Alzheimer's disease.     

Three-Dimensional Soft Tissue Prediction Using Finite Elements

Abstract Background and Aim: The prediction of soft tissue esthetics is important for achieving an optimal esthetic outcome in orthodontic treatment planning. Applicable procedures have so far been restricted to two-dimensional profile predictions that have not proven to be very reliable. The goal of this investigation was therefore to develop a novel finite element-based procedure that allows a three-dimensional, easily visualized, quantitative analysis and prediction of soft tissue behavior for the clinician. The procedure to be developed should be easy to handle and not entail any additional radiation exposure for the patient. Material and Methods: Using a three-dimensional scanner, the facial surfaces of 20 probands were digitalized and individual FEM models were generated. Results: After reduction of data redundancy via several conversion steps, a patient-specific simulation model was prepared consisting of 20,000 to 40,000 individual elements to which specific physical properties could be assigned. The average time required for generating a virtual model was 50 minutes. Problems occurring during model generation were rare (mainly shadowing phenomena and movement artifacts). Conclusion: The procedure outlined herein makes the reliable generation of patient-specific simulation models possible for facial soft tissue prediction in orthodontics.     

Effect of divalent cations on structure-function relationships of the antitumor protein α-sarcin

α-Sarcin binds one Zn(II) cation per protein molecule, with a K_d value of 0.9 mM, determined by equilibrium dialysis experiments. Ca(II), Mg(II), and Mn(II) do not bind to α-sarcin. Cd(II) and Co(II) also behave as Zn(II). The binding produces local modifications on the protein conformation affecting the microenvironment of tryptophan residues. The three cations modify the fluorescence emission of the protein. The near-u. v. circular dichroism spectrum of the protein is also altered. The binding of Zn(II) and related cations does not modify the secondary structure of the protein. The ribonucleolytic activity of a-sarcin is inhibited upon Zn(II) binding, but no alteration of the ability of the protein to aggregate phospholipid vesicles has been observed.     

Parvalbumin-immunoreactive neurons in the cerebral cortex of the lizardPodarcis hispanica

An antibody against the calcium binding protein parvalbumin selectively labels a set of neurons in the cerebral cortex of lizards. Golgi-like immunostained bipolar, multipolar and pyramid-like neurons appear mainly located in the inner plexiform layers. Parvalbumin-immunoreactive (PARV-IR) puncta are concentrated in the cell layer of the dorsal and dorsomedial cortices showing a basket-like distribution. The morphology and distribution of PARV-IR neurons and puncta overlap GABA-immunostaining in the cerebral cortex of lizards. Thus, it is likely that PARV-IR neurons are a subset of the cortical GABAergic neurons of lizards.     

Neurochemical studies on the mesolimbic circuitry of antinociception

Previous studies using the technique of microinjection into brain nuclei indicated that the periaqueductal gray (PAG), nucleus accumbens, habenula and amygdala play an essential role in pain modulation and that these nuclei possibly act through a ‘mesolimbic neural loop‘ to exert an analgesic effect, in which Met-enkephalin (MEK) and β-endorphin (β-EP) have been implicated as the two major opioid peptides involved in antinociception. In the present study performed in rabbits, intracranial microinjection was supplemented with push-pull perfusion and radioimmunoassay to determine whether the release of enkephalins (ENK) and β-EP was increased in these nuclei when the putative neural circuit was activated by morphine administered into one of the nuclei. The results showed: (1) microinjection of morphine into the PAG increased the release of ENK and β-EP in the N. accumbens, and vice versa; (2) microinjection of morphine into the N. accumbens increased the release of ENK and β-EP in the amygdala, and vice versa; (3) morphine microinjected into the PAG caused an increase in the release of ENK and β-EP in the amygdala and vice versa, although the release of ENK in PAG was statistically not significant. These results indicate that PAG, N. accumbens and amygdala are connected in a network served by a positive feedback circuitry.     

Activation of 5-HT3 receptor by 1-phenylbiguanide increases dopamine release in the rat nucleus accumbens

The serotonin-3 (5-HT₃) agonist 1-phenylbuguanide (0.1–1.0 mM in perfusate) caused a robust, dose-dependent enhancement of extracellular dopamine content in nucleus accumbens as measured by in vivo microdialysis. This action was antagonized by co-perfusion of the 5-HT₃ antagonists zacopride and GR38032F (1 mM in perfusate). Similar effects were observed in 5-HT-denervated rats. These findings suggest that there is a potent modulation of dopamine (DA) release in the nucleus accumbens mediated via 5-HT₃ receptors, which appear to be located presynaptically on DA terminals of the mesolimbic DA pathway.     

复方积雪草有效组分对人肾小管上皮细胞补体C3表达的影响

目的：探讨复方积雪草有效组分——积雪草苷／大黄素干预肿瘤坏死因子-α（TNF-α）诱导的人肾近曲小管上皮细胞（HPTEC）补体C3 mRNA及蛋白的表达水平。方法：采用HPTEC，模型组TNF-α 10ng／ml诱导，治疗组在TNF-α诱导的同时，以不同浓度的积雪草苷、大黄素以及积雪草苷合大黄素进行干预，于24h后分别提取细胞RNA及上清，应用逆转录-聚合酶链反应（RT—PCR）和酶链免疫方法（ELISA）分别检测HPTEC C3 mRNA和蛋白的表达。结果：正常HPTEC具有C3 mRNA和蛋白表达，经TNF-α诱导后G表达明显上调，用不同浓度的积雪草苷、大黄素以及积雪草苷合大黄素干预后，C3 mRNA及蛋白水平表达出现不同程度的下调，呈一定的剂量依赖关系和协同作用。结论：复方积雪草有效组分能够抑制炎性细胞因子TNF-α上调所致的肾局部G过度产生。     

PRO 1000 V3型心电监护仪LCD逆变器的升级及注意事项

介绍了该型心电监护仪黑屏故障的常见原因，对升级前后的LCD逆变器电路作了对比分析，并详细介绍了升级更换的方法和注意事项。     

SH3GL2在无病灶性难治性癫(癎)患者脑组织中的表达

目的:分析无病灶性难治性癫患者脑组织中SH3GL2 mRNA与蛋白的表达水平,探讨可能的发病机制。方法:运用逆转录-聚合酶链式反应(RT-PCR)和Westernblot分别检测10例无病灶性难治性癫患者及10例对照组脑组织SH3GL2 mRNA及蛋白的表达。结果:RT-PCR检测显示,无病灶性难治性癫患者脑组织SH3GL2 mRNA表达的相对水平为(102.23±54.68),对照组为(44.59±17.12),两者差异有显著统计学意义(P<0.01);Westernblot分析表明,无病灶性难治性癫患者脑组织的SH3GL2蛋白表达相对水平(229.54±89.82)高于对照组(143.88±59.69),两者差异也有显著统计学意义(P<0.05)。结论:SH3GL2 mRNA与蛋白表达水平在无病灶性难治性癫患者脑组织中明显增强,提示表达于中枢神经系统的SH3GL2可能在人类难治性癫的发病机制中起了一定作用。