Factors to keep in mind when introducing virtual microscopy

Digitization of glass slides and delivery of so-called virtual slides (VS) emulating a real microscope over the Internet have become reality due to recent improvements in technology. We have implemented a virtual microscope for instruction of medical students and for continuing medical education. Up to 30,000 images per slide are captured using a microscope with an automated stage. The images are post-processed and then served by a plain hypertext transfer protocol (http)-server. A virtual slide client (vMic) based on Macromedia's Flash MX, a highly accepted technology available on every modern Web browser, has been developed. All necessary virtual slide parameters are stored in an XML file together with the image. Evaluation of the courses by questionnaire indicated that most students and many but not all pathologists regard virtual slides as an adequate replacement for traditional slides. All our virtual slides are publicly accessible over the World Wide Web (WWW) at http://vmic.unibas.ch . Recently, several commercially available virtual slide acquisition systems (VSAS) have been developed that use various technologies to acquire and distribute virtual slides. These systems differ in speed, image quality, compatibility, viewer functionalities and price. This paper gives an overview of the factors to keep in mind when introducing virtual microscop

Anatomic site-specific patterns of gene copy number gains in skin, mucosal, and uveal melanomas detected by fluorescence in situ hybridization

To assess the differences between melanomas of different location and different etiology, 372 malignant melanomas were brought in a tissue microarray format. The collection included 23 acral and 118 non-acral skin melanomas, 9 mucosal melanomas, 100 uveal melanomas, and 122 melanoma metastases. Fluorescence in situ hybridization (FISH) was used to assess copy number changes of the cyclin D1 (CCND1), MDM2, c-myc (MYC), and HER2 genes. FISH analysis revealed distinct differences between melanomas from different locations. CCND1 amplifications were detected in skin melanomas from sites with chronic sun exposure (6 of 32 cases), acral melanomas (4 of 17 cases), and mucosal melanomas (one of ten cases) but not in uveal melanomas. High-level MDM2 amplifications were exclusively present in acral melanomas (2 of 19 cases). MYC copy number gains were detected in 32 of 71 uveal melanomas, five of eight mucosal melanomas, and 6 of 67 melanomas from sites with intermittent sun exposure but not in acral melanomas nor melanomas from sites with chronic sun exposure. Alterations of the MYC gene were associated with advanced tumor stage. There were no high-level HER2 amplifications. Site-specific genetic and epigenetic features may impact the response of melanomas to various anti-cancer drugs and should be considered in future studies on the molecular pathogenesis of malignant melanoma

Expression and amplification of therapeutic target genes in retinoblastoma

Purpose: We set out to evaluate alterations of the therapeutic target genes KIT (CD 117), EGFR, and HER-2 in human retinoblastoma. Methods: Ninety-five formalin-fixed, paraffin-embedded retinoblastomas were brought into a tissue microarray (TMA) format. Immunohistochemistry was performed to analyze the expression of CD117, EGFR, and HER-2. Fluorescence in situ hybridization (FISH) was utilized for detection of EGFR amplifications. Three tumors with strong CD117 positivity were sequenced for KIT exon 11 mutations. Results: Detectable CD117 expression was seen in 19% of all interpretable cases. Sequence analysis of the three tumors with the strongest CD117 expression revealed no mutations. EGFR was positive in 14% of all cases. No EGFR amplification was observed by FISH, however. All tumors were negative for HER-2 expression. Conclusions: Our data suggest that selected cases of retinoblastoma may be candidates for anti-EGFR and imatinib mesylate (STI571) therap

Acute Renal Failure on Immune Reconstitution in an HIV-Positive Patient with Miliary Tuberculosis

Immune reconstitution syndrome following HAART in human immunodeficiency virus (HIV)-infected patients is characterized by inflammatory worsening of organ functions despite improvement in HIV surrogate markers of HIV infection. We describe a patient with miliary tuberculosis and urinary shedding of acid fast bacilli who developed acute renal failure 8 weeks after initiation of antituberculosis therapy and 6 weeks after initiation of HAART. The diagnostic workup and further course of disease implicated immune reconstitution syndrome as the cause of acute renal failur

Sequence analysis and high-throughput immunhistochemical profiling of KIT (CD 117) expression in uveal melanoma using tissue microarrays

We aimed to immunohistochemically examine the expression of KIT (CD 117) in human posterior uveal melanoma and to analyze KIT-positive tumors for gene mutations. Brought into a tissue microarray (TMA) format were 101 formalin-fixed, paraffin-embedded posterior uveal melanomas. Immunhistochemistry was performed using the polyclonal anti-CD117 antibody from Dako (A4502). In ten selected KIT-positive tumors, exons 2, 8, 9, 11, 13 and 17 were sequenced. Of the 101 cases, 89 (88%) could be evaluated on the TMAs. Immunohistochemistry for CD 117 was weakly positive in 5 cases (6%), moderately positive in 10 cases (12%) and strongly positive in 57 cases (69%). No KIT mutations were detected in the analyzed exons. In conclusion, human posterior uveal melanoma frequently expresses CD117 at high levels. Although KIT mutations could not be found, it appears justified to investigate the utility of imatinib mesylate in the treatment of these patient

Involvement of peptidylarginine deiminase 4 in eosinophil extracellular trap formation and contribution to citrullinated histone signal in thrombi

Background: Extracellular traps formed by neutrophils (NETs) and eosinophils (EETs) have been described in coronary thrombi, contributing to thrombus stability. A key mechanism during NET formation is histone modification by the enzyme PAD4. Citrullinated histones, the product of PAD4 activity, are often attributed to neutrophils. Eosinophils also express high levels of PAD4. Objectives: We aimed to explore the contribution of PAD4 to EET formation. Methods: We performed immunohistological analyses on thrombi, including a large, intact, and eosinophil-containing thrombus retrieved from the right coronary artery using an aspiration catheter and stroke thrombi from thrombectomy retrieval. We studied eosinophils for their capability to form PAD4-dependent EETs in response to strong ET-inducing agonists as well as activated platelets and bacteria. Results: Histopathology and immunofluorescence microscopy identified a coronary thrombus rich in platelets and neutrophils, with distinct areas containing von Willebrand factor and citrullinated histone H3 (H3Cit). Eosinophils were also identified in leukocyte-rich areas. The majority of the H3Cit+ signal colocalized with myeloperoxidase, but some colocalized with eosinophil peroxidase, indicating EETs. Eosinophils isolated from healthy volunteers produced H3Cit+ EETs, indicating an involvement of PAD4 activity. The selective PAD4 inhibitor GSK484 blocked this process, supporting PAD4 dependence of H3Cit+ EET release. Citrullinated histones were also present in EETs produced in response to live Staphylococci. However, limited evidence for EETs was found in mouse models of venous thrombosis or infective endocarditis. Conclusion: As in NETosis, PAD4 can catalyze the formation of EETs. Inhibition of PAD4 decreases EET formation, supporting the future utility of PAD4 inhibitors as possible antithrombotic agents

Control of angiogenesis and host response by modulating the cell adhesion properties of an Elastin-Like Recombinamer-based hydrogel

Producción CientíficaThe control of the in vivo vascularization of engineered tissue substitutes is essential in order to obtain either a rapid induction or a complete inhibition of the process (e.g. in muscles and hyaline-cartilage, respectively). Among the several polymers available, Elastin-Like Recombinamers (ELR)-based hydrogel stands out as a promising material for tissue engineering thanks to its viscoelastic properties, non-toxicity, and non-immunogenicity. In this study, we hypothesized that varying the cell adhesion properties of ELR-hydrogels could modulate the high angiogenic potential of adipose tissue-derived stromal vascular fraction (SVF) cells, predominantly composed of endothelial/mural and mesenchymal cells. Human SVF cells, embedded in RGD-REDV-bioactivated or unmodified ELR-hydrogels, were implanted in rat subcutaneous pockets either immediately or upon 5-day-culture in perfusion-bioreactors. Perfusion-based culture enhanced the endothelial cell cord-like-organization and the release of pro-angiogenic factors in functionalized constructs. While in vivo vascularization and host cell infiltration within the bioactivated gels were highly enhanced, the two processes were strongly inhibited in non-functionalized SVF-based hydrogels up to 28 days. ELR-based hydrogels showed a great potential to determine the successful integration of engineered substitutes thanks to their capacity to finely control the angiogenic/inflammation process at the recipient site, even in presence of SVF cells.Ministerio de Economía, Industria y Competitividad (Project MAT-2010-15982, MAT2010- 15310, PRI-PIBAR-2011-1403 and MAT2012-38043-C02-01)Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref.VA152A12-2, VA244U13 and VA155A12-2

Untersuchungen zum Wärmestrom zwischen Tier und Liegefläche

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Frequent mitotic activity in banal melanocytic nevi uncovered by immunohistochemical analysis

The presence and distribution of mitotic figures is an important discriminatory parameter in the assessment of melanocytic lesions. We evaluated the number and distribution of mitotic figures in 353 randomly collected melanocytic nevi of various subtypes by hematoxylin and eosin (H;E) staining and immunohistochemically with the 2 mitotic markers Phospho-Histone H3 Ser28 (PHH3) and MPM2. At least 1 mitotic figure was present in 19.5%, 31.3%, and 42.8% of H;E-, PHH3-, and MPM2-stained lesions, respectively. In common compound nevi, the mean number of dermal mitoses amounted to 0.024/mm dermal surface area in the H;E staining (PHH3: 0.061; MPM2: 0.087) and to 0.175/mm in Spitz nevi (PHH3: 0.325; MPM2: 0.45). Nevi exhibiting mitotic figures were significantly more frequent in the youngest age group (0-20 years) than in patients older than 50 years (P > 0.0001). In the upper half of the dermis, mitotic activity was roughly 3 times as frequent as compared with the lower half. Clusters of mitotic figures within the dermis were not observed. Mitotic activity in obviously benign melanocytic nevi is not rare even in the deep dermal part. More than 2 mitotic figures per lesion can usually be explained either by the nevus subtype, young patient age, traumatization, or inflammation. PHH3 and MPM2 are a valuable diagnostic adjunct in the evaluation of melanocytic tumors allowing more sensitive and faster recognition of mitotic figures and their distribution