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.     

Myelination of the corpus callosum in the cat: time course, topography, and functional implications

The parameters of myelin development were ascertained in two specific regions of the corpus callosum in a series of cats aged 12 postnatal days through adult. The posteriormost portion of the splenium and the anterior-most portion of the genu were examined in cross section by using the electron microscope. Measurements were made to determine the age at which myelin first appeared, the number and distribution of myelinated fibers, the number and distribution of myelin lamellae, and cross-sectional area of ensheathed axons during development. The results indicate that myelination begins and ends earlier in the anterior region of the callosum. Measurements of myelin lamellae indicate similarities between anterior and posterior regions of the callosum, although development occurs earlier in the genu than in the splenium. No evidence was found for a sequence in the size of axons acquiring myelin sheaths, except that extremely small fibers are the last to begin myelinating. Myelination of the splenium of the corpus callosum begins at the very end of the behavioral and physiological critical period for the corpus callosum's role in visual functional development (Elberger: Behav. Brain Res. 11:223-231, '84; Elberger and Smith: Exp. Brain Res. 57:213-223, '85). Since myelination of a pathway is used as an index of functional reliability, this indicates that the basis for the callosal role in developing visual functions is probably not based on its physiological input to visual cortex.     

胸椎椎弓根根外固定螺钉拔出力的实验研究

目的:比较两种胸椎椎弓根根外固定方法与经椎弓根固定方法的螺钉拔出强度,评价胸椎椎弓根根外固定的生物力学效果。方法:新鲜胸椎标本4具,共32个肋骨-椎骨序列,根据螺钉固定方法不同分为3组,A组采用经椎弓根固定,B组采用经横突-椎体固定,C组采用经改良肋横突法固定。根据所用螺钉规格不同将其分为4种不同测试条件:D1,螺钉直径5.5mm,长度40mm;D2,螺钉直径5.5mm,长度45mm;D3,螺钉直径6.5mm,长度45mm;D4,螺钉直径6.5mm,长度50mm。测试3种固定方法下的螺钉拔出力,并做统计学分析对比。结果:D1条件下A组拔出力为787.0±119.3N,B组为706.2±109.4N,C组为616.1±82.3N,3组间比较有显著性差异(P<0.01);D2条件下A组拔出力为862.3±128.7N,B组为811.4±113.6N,C组为655.1±92.2N,A、B组间比较无显著性差异(P>0.05),A、B组与C组比较有显著性差异(P<0.01);D3条件下,A组拔出力为855.3±117.1N,B组为938.0±131.5N,C组为861.3±117.8N,A、C组间比较无显著性差异(P>0.05),A、C组与B组比较有显著性差异(P<0.01);D4条件下A组拔出力为864.3±120.9N,B组为959.6±135.2N,C组为941.2±115.4N,A组与B、C组比较均有显著性差异(P<0.01),B、C组间比较无显著性差异(P>0.05)。结论:使用直径6.5mm、长度45～50mm的螺钉固定时,胸椎椎弓根根外固定螺钉拔出力优于椎弓根固定,有较好的生物力学效果。     

Evidence for motility and pinocytosis in ramified microglia in tissue culture

Ramified microglial cells were investigated in primary cultures of dissociated cerebral cortical tissue from rats. The identification of these cells was confirmed through immunohistochemical staining with 7 monoclonal antibodies selective for microglia. While there was significant variation in staining intensity with different antibodies, all stained the identified ramified cells; the antibodies OX-42 and ED1 yielded the most intense immunoreactivity. Based on distinctive morphological features, the microglia could be identified in living cultures where they were monitored using time-lapse video recording. This technique revealed extremely dynamic features of cellular plasticity and motility. Ramified microglia exhibited constant and rapid alterations in the size and shape of their cell body with an associated extension and retraction of processes; concomitantly, the cells moved about in a circumscribed area. These features of plasticity and motility were unique to this cell type, and correlated with OX-42 immunostaining. The microglia also possessed a differentially high level of pinocytotic activity; this too was correlated with OX-42 staining. From the nature of their morphological plasticity and motility, high pinocytosis, and cellular distribution, it is hypothesized that the ramified microglia specifically function as a system of fluid cleansing in normal brain tissue.     

Preliminary evaluation of vitiligo using in vivo reflectance confocal microscopy

BACKGROUND: Vitiligo is the most common pigmentary disorder with a global incidence from 0.1% to 2% in different geographical areas. Histopathology and histochemistry have shown the reduction of melanocytes in achromic patches, but microscopic changes of lesional and non-lesional skin are still not completely understood. Reflectance confocal microscopy (RCM), based on the different light reflectance index of cutaneous structures, allowed in vivo, en face microscopic evaluation of superficial skin layers with a resolution similar to skin histology. AIM: The purpose of this study was to evaluate RCM features of lesional and non-lesional skin of vitiligo patients. Moreover, re-pigmented areas were taken into consideration in order to evaluate melanocyte response to ultraviolet B (UVB) radiation. SUBJECTS AND METHODS: Sixteen patients of different phototypes affected by active non-segmental vitiligo and 10 controls were enrolled in the study. In vivo skin imaging was done using a commercially available RCM (Lucid, Vivascope 1500. Re-pigmented areas from 6 to 16 patients (after UVB narrow-band therapy) were also examined. RESULTS: Vitiligo lesions showed the disappearance of the bright rings normally seen at the dermo-epidermal junction. Moreover, non-lesional skin of vitiligo patients showed unexpected changes as the presence of half-rings or scalloped border-like features of the bright papillary rings. In re-pigmented areas after UVB narrow band therapy, the presence of activated, dendritic melanocytes was seen. CONCLUSIONS: Considering our results, and following further studies, RCM clinical applications could be used in the therapeutic monitoring and evaluation of the evolution of vitiligo.     

高功率微波辐照对大鼠血睾屏障通透性的影响

目的 探讨高功率微波（HPM）辐照大鼠睾丸对血睾屏障的影响。方法 雄性SD大鼠35只，随机分为7组，每组5只。6组为辐照组，1组为对照组。于辐照后2、6、12、4．8、96h和8d活杀大鼠后取双侧睾丸组织各约1mm^3，镧-醛固定液固定后制备电镜标本，在透射电镜下进行观察。结果 对照组可见硝酸镧主要沉积在曲细精管基膜部和精原细胞周围，未越过紧密连接；辐照后2-6h电镜下所见与对照组大致相同；辐照后12-96h，从基底部到管腔面的各层生精细胞之间、支持细胞内都有大量的镧颗粒沉积；辐照后8d，仍可见细胞间隙增大，部分区域靠近精子表面的镧颗粒沉积甚至比前面时间点的更为严重。结论 高功率微波辐照能够改变细胞的通透性，破坏血睾屏障的保护作用。     

水面长航舰载保存血液生化指标的实验研究

目的探讨和观察经水面长航舰载保存血液出海前后对生化指标的影响与变化。方法随机采集和制备WB、AS-RBC和LP-RBC各18人份(200ml)。每份血液各等分为4袋,配对设计为实验组(A区、B区和C区)与对照组。分别于长航前和长航后进行血液生化指标检测。结果①K+和P3+浓度在三种血液制品的实验组与对照组各观察点的结果均随保存血液时间的延长而增高(P<0.05或P<0.01);Na+浓度由长航前的水平而逐步降低(P<0.01);P3+、Mg2+实验组和对照组较长航前增高,Cl-、Ca2+的含量与长航前没有显著变化;②LDH、AST、CKP和HBDH结果实验组和对照组均呈递增趋势,AKP结果实验组和对照组均呈下降表现,ALT与GGT结果在长航前后变化不明显;③Glu指标减低,UA呈上升趋势。结论长航对血液保存有一定的影响,但总的变化趋势与常规(4±2)℃血库冰箱保存相似。此项研究对于我们进一步探索海上血液保障与运输以及血液海上救护均具有十分重要的实用和军事价值。     

Ultrastructure of aberrant serotonin-immunoreactive fibers in the caudate putamen complex of the aged rat

Degeneration of neurons in the central nervous system is associated with morphological changes. Previous observations made at the light microscopical level indicated degeneration of serotonin-immunoreactive (IR) fibers in the aged rat brain. In this study, a comparison at the ultrastructural level was made between serotonin-IR normal thin and aberrant swollen varicose fibers in the caudate-putamen complex of the aged rat. Ultrastructural features such as the size and content of the thin varicose fibers resembled those in the caudate-putamen complex of the young rat as reported by others. The aberrant profiles were swollen, reaching a size of 6 microns. Their vesicles varied in size and were no longer uniformly round. Moreover, distorted mitochondria and membrane-filled vacuolelike structures were a common feature of the aberrant profiles. These changes are indicative of a degenerative process and give further evidence that, whereas many serotonergic fibers are preserved at high age, other serotonergic fibers are degenerating in the caudate-putamen complex of the aged rat.     

雷公藤内酯对人胃癌细胞株FGC_(85)杀伤作用的光镜和电镜观察

本文应用核苷掺入技术及电镜观察首次证实雷公藤内酯对人胃癌细胞株 FGC_(85)的杀伤作用。用药早期,细胞数,分裂指数及 DNA,RNA 合成无明显变化,但出现核仁脱粒及核仁破碎等变化;晚期,电镜观察发现细胞以凋落方式死亡,药物主要作用于间期细胞,其杀伤机构的始动环节可能与核酸代谢障碍无关。