Effect of artifacts due to flowing blood on the reproducibility of phase-contrast measurements of myocardial motion

The reproducibility of myocardial motion trajectories calculated from cine phase-contrast (PC) velocity data is reduced by artifacts due to the inconsistent motion of intracardiac blood. Spatial presaturation reduces these artifacts but requires a longer sequence TR, with a potentially negative effect on trajectory accuracy and reproducibility. We investigated the effect of spatial presaturation on trajectory reproducibility. A midventricular transaxial slice was imaged in five normal volunteers. The same slice was imaged three times each with sequences using spatial presaturation or not. Because the most serious artifacts originate in the heart chambers and propagate in the phase-encoded direction, myocardial regions that were in line with the heart chambers (in the phase-encode direction) had the highest artifact level in the scans without spatial presaturation. The reproducibility of trajectories for regions placed in these areas (the anterior wall, septum and posterior wall in the transaxial scans with phase encoding in the anterior-posterior direction) improved by a factor of two when presaturation was used (P < .001). In areas that were not in line with the heart chambers (eg, the anterior aspect of the lateral wall in the transaxial scans), the effect of presaturation was not significant. These results correlate well with the measured reduction in artifact level. The reproducibility of myocardial motion trajectories over large areas of the heart is improved to approximately 1 mm when presaturation is used. Therefore, use of presaturation is recommended for myocardial motion studies using cine PC velocity data.     

Evidence that neurofibrillary tangles undergo glial modification

Summary Ghost tangles, neurofibrillary tangles (NFTs) emerging into extracellular space, appear to be subjected to some microglial association in addition to an invasion of astrocytic processes. Our findings lead us to speculate that the NFTs undergo structural and immunocytochemical modification. Electron microscopic observation of the NFTs in the vascular region indicated either the discharge of NFTs into the vessel or formation of NFTs in the astrocytic end-foot.     

Extracellular or ghost Pick bodies and their lack of tau immunoreactivity: a histological,immunohistochemical and electron microscopic study

Histological, immunohistochemical, and electron microscopic evidence of an extracellular, or ghost Pick body has been found in the granular cell layer and, rarely, in the pyramidal cell layer of the hippocampus of an autopsy case of Pick's disease. The ghost Pick body appeared as a blurred, weak argyrophilic mass in the neuropil, and it was composed of accumulated fibrillary structures, 13 nm in diameter, intermingled with glial filament bundles. These ghost Pick bodies did not react with anti-tau and antiubiquitin antibodies, but did react weakly with antiglial fibrillary acidic protein antibody, whereas intracytoplasmic Pick bodies were strongly immunolabeled with anti-tau but only weakly with anti-ubiquitin anti-bodies. These results suggest that the Pick body is discharged into the neuropil after destruction of the mother neuron, loses its immunoreactivity to certain tau and ubiquitin antibodies during this process (thereby inducing a glial reaction) and remains in the neuropil as a ghost Pick body.     

El plagio y las revistas depredadoras como amenaza a la integridad científica

This article presents an analysis of the concept of plagiarism in order to show the wide spectrum of manifestations that can be considered as such when committing a transgression of intellectual property, carried out with the intention of deceiving the authors’ true contribution and the originality and novelty of the information.The article describes the concurrent circumstances in intentional plagiarism, and the damage that this misconduct causes in the credibility of the scientific system, in which authorship credit is the foundation of the academic career, of the prestige of the author in the scientific community, and the basis for research funding.Some circumstances are favouring this fraud: the pressure exerted on researchers by the criteria used for promotion and reward that prioritise the quantity of works on their quality, the existence of a market for the purchase and sale of scientific articles, and the proliferation of predatory journals that operate without or minimal ethical standards.Finally, the paper highlights the convenience of the adoption of criteria that prioritise the intrinsic quality of the work versus its quantity, including the active involvement of the institutions in the development of active policies for the prevention, detection, and punishment of the cases of potential fraud, and emphasize that, in the end, the prevention of fraud relies on the individual adoption of an ethical and responsible behaviour.     

射频消融治疗兔肝VX2肿瘤后消融病灶鬼影细胞的形态变化

目的 观察射频消融治疗兔VX2肿瘤后病灶鬼影细胞存在的时间及不同时间段形态的变化.方法 将VX2肿瘤组织块接种于32只新西兰兔肝脏,建立肝脏肿瘤模型,2周后控制肿瘤边缘温度行射频治疗,于治疗结束后0、1、2、4周切取标本,在相邻切面分别行HE染色、NADH活力染色,观察鬼影细胞存在时间以及随时间变化过程.结果 射频治疗结束后4周,HE染色下鬼影细胞形态无明显变化,NADH染色显示无活力.结论 消融灶鬼影细胞形态至少能保持到治疗后4周,HE染色不能辨别是否是残癌,必须加用NADH活力染色,才能与残癌正确区分.     

Regional odontodysplasia: a review of the literature and report of four cases

Regional odontodysplasia (RO) is a rare dental anomaly involving both dentitions, mostly teeth of one quadrant. The characteristic findings are discolored soft teeth accompanied by gingivitis, swelling or abscess. Enamel and dentin are hypomineralised and hypoplastic, so that the ghost teeth appear shadowy in radiographs with wide pulp chambers. The etiology is unknown. Epidemiological data is rare; 138 cases of RO have been published to date and reports on ultrastructure are few. An analysis of published cases of RO in the international literature is presented. The sex ratio of females to males was 1.7:1. The age at the time of diagnosis ranged between 4 and 23 years. The maxilla was more often affected (maxilla to mandible ratio 1.6:1). In 67 patients the deciduous and permanent dentitions were affected (47.1%). In 129 cases, affected teeth lay side by side. Missing tooth development was observed in 10.7%. Failure of tooth eruption of RO teeth occurred in 39.7%. In addition, four cases with RO which were collected over a period of more than 25 years are presented. Ultrastructural findings of one specimen are demonstrated.     

西门子永磁型磁共振尖峰脉冲（Spike）干扰的检查与排除

介绍了西门子永磁型磁共振尖峰脉冲干扰的产生原因,分析并提供了其检查和排除的方法。     

Histochemische Untersuchungen an Nervenzellen mit experimentell erzeugten fibrillären Ablagerungen durch Aluminiumphosphat

Zusammenfassung Die motorischen Vorderhornzellen bei 12 Kaninchen wurden nach intrathekaler Injektion von Aluminiumphosphat histochemisch untersucht. Alle Tiere zeigten schwere Nervenzellveränderungen. Wir fanden nach 3 Tagen hochaktive Kernkappen und auch bei fortgeschritten erkrankten Zellen in späteren Stadien immer noch scharf abgegrenzte Cytoplasmabezirke mit erhaltenen Fermentreaktionen. Schalenförmige perinucleäre und grotesk deformierende Ablagerungen im Cytoplasma zeigten im polarisierten Licht eine Doppelbrechung. Zahlreiche Zellfortsatzauftreibungen glichen den sogenannten Ghost cells. Die Befunde an den abgelagerten Substanzen weisen auf eine Proteinkomponente hin; die Nachweise für Lipide und für Kohlenhydrate waren negativ, für saure Mucopolysaccharide schwach positiv.

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Histochemical investigations of nerve cells with fibrillary tangles produced by aluminium phosphate

Summary The motoneurons of 12 rabbits were studied histochemically after injection of aluminium phosphate solution. All animals showed severe nerve cell changes. We found highly active perinuclear zones and also in more affected cells sharply bordered cytoplasmatic areas with intact enzyme function. Deposits around the nucleus and elsewhere in the cytoplasm were deforming the cell. In the polarized light one could see a birefringence within the deposits. Numerous distended nerve cell processes were recognized as so called ghost cells. The results seem to indicate that the substances found are composed from proteins and to a minor extent also from acid mucopolysaccharides. No lipids and carbohydrates could be found.

Nach einem am 15. Oktober 1966 im Rahmen des XI. Symposions der Gesellschaft für Histochemie in München gehaltenen Vortrag.     

Notch signaling and ghost cell fate in the calcifying cystig odontogenic tumor

Notch signaling is an evolutionarily conserved mechanism that enables adjacent cells to adopt different fates. Ghost cells (GCs) are anucleate cells with homogeneous pale eosinophilic cytoplasm and very pale to clear central areas (previous nucleus sites). Although GCs are present in a variety of odontogenic lesions notably the calcifying cystic odontogenic tumor (CCOT), their nature and process of formation remains elusive. The aim of this study was to investigate the role of Notch signaling in the cell fate specification of GCs in CCOT. Immunohistochemical staining for four Notch receptors (Notch1, Notch2, Notch3 and Notch4) and three ligands (Jagged1, Jagged2 and Delta1) was performed on archival tissues of five CCOT cases. Level of positivity was quantified as negative (0), mild (+), moderate (2+) and strong (3+). Results revealed that GCs demonstrated overexpression for Notch1 and Jagged1 suggesting that Notch1-Jagged1 signaling might serve as the main transduction mechanism in cell fate decision for GCs in CCOT. Protein localizations were largely membranous and/or cytoplasmic. Mineralized GCs also stained positive implicating that the calcification process might be associated with upregulation of these molecules. The other Notch receptors and ligands were weak to absent in GCs and tumoral epithelium. Stromal endothelium and fibroblasts were stained variably positive.