A Case forthe Panel Foreign:Material in the Tissues of Patients on Recurrent Hemodialysis

Ernst Ruska: The Early Development of Electron Lenses and Electron Microscopy Translated by Thomas Mulvey Stuttgart: S. Hirzel Verlug, 1980 140 pages, 82 figures. In boards DM 48.     

Ultrastructural hepatocytic alterations induced by silver nanoparticle toxicity

Silver nanoparticles (SNPs) are widely used in nanomedicine and consuming products with potential risk to human health. While considerable work was carried out on the molecular, biochemical, and physiological alterations induced by these particles, little is known of the ultrastructural pathological alterations that might be induced by nanosilver materials. The aim of the present work is to investigate the hepatocyte ultrastructural alterations that might be induced by SNP exposure. Male rats were subjected to a daily single dose (2 mg/kg) of SNPs (15–35 nm diameter) for 21 days. Liver biopsies from all rats under study were processed for transmission electron microscopy examination. The following hepatic ultrastructural alterations were demonstrated: mitochondria swelling and crystolysis, endoplasmic reticulum disruption, cytoplasmic vacuolization, lipid droplets accumulation, glycogen depletion, karyopyknosis, apoptosis, sinusoidal dilatation, Kupffer cells activation, and myelin figures formation. The current findings may indicate that SNPs can induce hepatocyte organelles alteration, leading to cellular damage that may affect the function of the liver. These findings might indicate that SNPs potentially trigger heptocyte ultrastructural alterations that may affect the function of the liver with potential risk on human health in relation to numerous applications of these particles. More work is needed to elucidate probable ultrastructural alterations in the vital organs that might result from nanosilver toxicity.     

应用深度学习网络实现肾小球滤过膜超微病理图像的语义分割

肾小球滤过膜包含内皮细胞、肾小球基底膜和足细胞3层超微结构,其形态改变是诊断肾小球疾病的重要指标之一。准确的滤过膜语义分割有助于病理医生识别和判断滤过膜细微的病理改变,为相关的病理诊断提供帮助。由于肾小球滤过膜的超微病理图像不仅结构复杂而且灰度分辨率很低,传统的分割算法均只能对其中形态最简单的基底膜部分进行分割,分割精度也难以保证。本文提出基于深度学习网络DeepLab-v3的肾小球滤过膜自动语义分割算法,应用空洞卷积扩大感受野,控制图像的特征分辨率,再通过空洞空间金字塔池化来获得多尺度的图像信息,最终将肾小球滤过膜的3个组成部分同时分割出来,并均能达到较好的分割效果。本文通过对重要参数进行实验探究,使得平均分割准确度达到0.776,是目前效果相对较好的模型。     

母鼠低剂量接触甲基汞所致仔鼠学习能力及脑海马超微结构的变化

[目的]研究ICR母鼠饮水暴露低剂量氯化甲基汞(MeHgCl)后,仔鼠脑组织的病理组织学变化和脑海马超微结构变化,评价低剂量饮水暴露甲基汞的安全性。[方法]ICR孕鼠随机分为对照组、低剂量组和高剂量组,每组各8只,各组于怀孕第6天起,分别自由饮用蒸馏水和氯化甲基汞含量为0.01、0.1mg/L的蒸馏水,直至哺乳期结束。测试各组仔鼠学习能力,观察仔鼠脑组织病理组织学变化及脑海马超微结构变化。[结果]在对仔鼠进行学习能力测试的水迷宫实验中,对照组、低剂量组和高剂量组成功率分别为81.67%、59.09%和70.00%,低剂量组和高剂量组成功率显著低于对照组(P<0.05)。低剂量组和高剂量组仔鼠脑组织有明显的病理学改变,随着甲基汞染毒剂量的增加,海马区大锥体细胞、大脑神经元和小脑浦肯野细胞嗜酸性增强。电镜结果显示,低剂量和高剂量组脑海马神经细胞有变性,严重者呈暗细胞表现。[结论]实验剂量甲基汞可使仔鼠脑组织发生病理组织学改变,脑海马区超微结构改变,实验剂量甲基汞对于仔代是不安全的。     

Differential subcellular localization of the 5-HT3-As receptor subunit in the rat central nervous system

Following the cloning and sequencing of the A subunit of the 5-HT3 receptor, two alternatively spliced isoforms, 5-HT3-AS and 5-HT3-AL, have been identified. In order to analyse the distribution of the receptor, a polyclonal antibody has been produced against the short form which is the most abundant in the central nervous system [Doucet et al. (2000) Neuroscience 95, 881-892]. As expected from the recognition of functional 5-HT3 receptors, immunostaining by this anti-5-HT3-R-AS antibody matched the distribution of the high-affinity 5-HT3 binding sites in the rat brain and spinal cord. 5-HT3-AS-like immunoreactivity was detected at low levels in the limbic system, particularly in the amygdala and the hippocampus, and in the frontal, piriform and entorhinal cortices. High levels of immunoreactivity were found in the brainstem, mainly in the nucleus tractus solitarius and the nucleus of the spinal tract of the trigeminal nerve, and in the dorsal horn of the spinal cord. At the ultrastructural level, immunostaining was generally found associated with axons and nerve terminals (70-80%) except in the hippocampus, where labelled dendrites were more abundant (56%). This preferential localization on nerve endings is consistent with the well-documented physiological role of 5-HT3 receptors in the control of neurotransmitter release. However, the different distribution in the hippocampus raises the question of whether differential addressing mechanisms exist for preferentially targeting 5-HT3 receptors to postsynaptic dendritic sites as compared to presynaptic nerve endings, depending on the nature of the neurons bearing these receptors.     

Subcellular localization of β-catenin and APC proteins in colorectal preneoplastic and neoplastic lesions

Adenomatous polyposis coli (APC) is a tumor suppressor gene whose main function is the destabilization of β-catenin, a key effector of the Wnt signaling pathway. This gene is defective in familial adenomatous polyposis (FAP), a dominantly inherited disease, but inactivation of APC has been reported also in most sporadic colorectal tumors and it is considered an early event in colorectal tumorigenesis. The aim of the present study was to evaluate the intracellular ultrastructural distribution of β-catenin and APC proteins in epithelial cells of normal colorectal mucosa, aberrant crypt foci (ACF, an early premalignant lesion) and cancer. We used the immunogold electron microscopic method to identify both proteins. Normal colonic epithelial cells showed a strong membranous expression of β-catenin and lacked cytoplasmic and nuclear expression. Normal cells showed APC localization pattern characterized by diffuse nuclear expression and along the plasma membrane. In ACF and in carcinoma an absent or reduced membranous expression of β-catenin was associated with an increased nuclear and cytoplasmatic expression. In aberrant crypt foci and carcinoma, APC was evident inside the nucleus and at the level of cell-cell junctions, but it was decreased in the cytoplasm. This method allowed the accurate localization of proteins of the Wnt signaling pathway in the early steps of colorectal carcinogenesis. The similar pattern of subcellular distribution of APC and β-catenin in dysplastic ACF and colorectal cancer suggests that ACF are precursor lesions of sporadic and FAP-associated colorectal carcinoma.     

Extraskeletal Ewing's sarcoma

Summary Clinicopathologic study of five cases of soft tissue tumors revealed distinct differences from skeletal Ewing's sarcoma in preferential localisation and mean age. The cases examined here are similar to cases described earlier as extraskeletal Ewing's sarcomas. They show light- and electronmicroscopical features analogous to skeletal Ewing's sarcoma. The term extraskeletal Ewing's sarcoma appears to be appropriate for this type of soft tissue tumor.

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Zusammenfassung Eine klinisch-pathologische Studie von fünf Patienten mit sogenannten extraskelettalen Ewingsarcomen ergab deutliche Unterschiede in bezug auf die Vorzugslokalisation und das Durchschnittsalter, gegenüber dem Ewingsarcom des Skelettsystem. Die licht- und elektronenmikroskopischen Befunde rechtfertigen jedoch den Begriff extraskelettales Ewingsarcom.

     

Ultrastructural cytochemical demonstration of peroxidase-positive monocyte granules: An additional method for studying the origin of mononuclear cells in encephalitic lesions

Summary Unlike lymphocytes, blood monocytes possess in their cytoplasm peroxidase-positive (azurophil) granules (ppg) which largely correspond to the homonymous organelles of neutrophil granulocytes. We tested whether ppg, demonstrated cytochemically at the submicroscopic level, could serve as markers of monocyte-derived reactive mononuclear cells in encephalitic lesions. Samples of cerebrocortical tissue from adult albino mice with experimental yellow fever virus encephalitis were incubated in a medium containing diaminobenzidine and H₂O₂ for localization of peroxidatic activity. Mononuclear cells exhibiting ppg were found (1) in the lumen of brain venules, (2) in different stages of migration through the walls of such vessels, (3) in perivascular areas, (4) in the glioneuropil, either loosely scattered or forming small clusters, (5) in a satellite position to neurons, and (6) in leptomeningitic infiltrates. Several mononuclear elements harboring ppg had assumed an elongated, rod cell-like out-line. Amongst the peroxidase-negative mononuclears were fully developed brain macrophages and elements showing morphologic features characteristic of activated lymphocytes. Most mononuclear cells without ppg resembled the peroxidase-reactive ones. The results of this study provide direct evidence in favor of a monocytic origin of, at least, numerous reactive mononuclear elements in encephalitic lesions. The approach followed in the present study is not suitable for quantitative investigations of the histogenesis of mononuclear cells responding to brain injuries, since emigrated blood monocytes rapidly lose their ppg, particularly, when they display enhanced phagocytic activity.The results of this work were presented at a scientific poster session held at the 22nd Annual Meeting of the Deutsche Gesellschaft für Neuropathologie und Neuroanatomie e.V., Tübingen, October 17–19, 1977This work was supported in part by a research fellowship awarded to Dr. Heike Herrlinger by the Deutsche Forschungsgemeinschaft, Bonn-Bad Godesberg, Federal Republic of Germany     

黄绿青霉素对心脏毒性损伤作用

目的观察黄绿青霉素（CIT）对离体心肌细胞及大鼠心肌组织结构和功能的损伤。方法电镜检查法观察黄绿青霉素致离体心肌细胞超微结构的改变,并对15mg/（kg·d）CIT喂饲8周的大鼠心肌组织进行病理学观察。结果光镜下CIT处理组大鼠心肌发生变性和坏死,病变呈灶状或条索状分布,有炎性细胞浸润,肌原纤维凝集崩解,部分心肌细胞颗粒变或空泡变性。电镜下,2.5μmol/L CIT组,细胞形状不规则,染色质边集,肌丝明显,胞质内存在脂滴颗粒,线粒体嵴清晰,部分线粒体空泡变性;25μmol/L CIT可使完整的肌细胞结构消失;随剂量增加,毒性作用增强。结论CIT在体内和体外均可引发心肌的变性和坏死。