6,272 research outputs found
Invoking Voids in the Archive
No full textThis is the author accepted manuscript. The final version is available from Camera Austria via the DOI in this recor
Impact of angiotensin-converting enzyme inhibition on platelet Tissue Factor expression in stroke-prone rats
No full textABSTRACT
Objective: Hypertension is a well-known risk factor for thrombotic events such as myocardial infarction and stroke. Platelets express tissue factor (TF), the key activator of blood coagulation and thrombus formation. The number of TF-positive platelets increases in pathological conditions characterized by thrombotic complications but whether this occurs in hypertension is unknown.
Here we investigated whether: 1) platelet TF expression is increased in a hypertensive status through a mechanism acting on megakaryocytes; 2) the phenomenon could be modulated by anti-hypertensive drug as captopril; 3) angiotensin influences platelet TF expression.
Methods: SHRSP rats received standard diet (StD) or a high-salt permissive diet (JpD). After 3 weeks, JpD animals were randomized to receive captopril or vehicle. Normotensive Wistar Kyoto (WKY) rats were used as controls. Cell-associated TF expression and activity were analyzed by flow cytometry and Calibrated Automated Thrombogram, respectively.
Results: Hypertensive StD-SHRSP showed an increased number of TF-positive platelet compared to normotensive WKY. After JpD administration, SHRSP developed severe hypertension and renal damage; the number of TF-positive megakaryocytes significantly increased compared to StD-SHRSP resulting in a higher number of TF-positive platelets with a faster kinetic of thrombin generation. These effects were reverted by captopril. Ex vivo stimulation of platelets, isolated from normotensive WKY and from healthy subjects, with angiotensin induced a concentration-dependent increase of surface-associated TF expression.
Conclusion: This study shows for the first time that in hypertension the number of TF-positive megakaryocytes increases thus releasing in the circulation more platelets carrying a functionally active TF. Angiotensin stimulates platelets to express TF
Do methodological differences account for the current controversy on tissue factor expression in platelets?
No full textAbstract
Tissue Factor (TF), the key activator of the blood coagulation cascade and of thrombus formation, is also expressed by circulating human platelets. Despite the documented in-depth characterization of platelet TF carried out in the past fifteen years, some authors still fail to identify TF in platelets, especially when assessment in platelet rich plasma (PRP) or washed platelets is carried out. This study aims to extend the characterization of the subset of TF-positive platelets in PRP from healthy subjects and to verify how different centrifugation forces, used to prepare the PRP, could affect the analysis of TF-positive platelets. Data indicate that large size platelets express significantly higher amount of TF compared to small size cells, both in terms of TF protein as well as of TF mRNA. Upon stimulation, large platelets readly expose on the cell membrane TF, which is functionally active, i.e. able to generate FXa as well as thrombin. By contrast, TF activity in small platelets is almost completely quenched by TFPI, becoming indeed detectable only after treatment with an anti-TFPI antibody.
Our data highlight that particular attention must be paid to the preparation and collection of the PRP since such pre-analytical variables may influence the platelet recovery and in turn affect subsequent analysis, whether it is flow cytometry, functional activity tests, proteome or transcriptome analysis. Indeed, the positive TF subset of large platelets can easily be lost if centrifugation protocols are not optimized, thus erroneously leading to a false negative result
Nuove acquisizioni sull'aterosclerosi: placca vulnerabile
No full textNuove acquisizioni sull’aterosclerosi: la placca vulnerabile
Marina Camera
Dip. Scienze Farmacologiche, Università degli Studi di Milano e Centro Cardiologico Monzino IRCCS Milano.
L'aterosclerosi è una patologia infiammatoria, degenerativa, a lenta progressione, caratterizzata dalla presenza di placche aterosclerotiche che possono andare incontro a rottura. L’evento trombotico conseguente alla rottura della placca è responsabile degli eventi cardiovascolari, quali angina instabile, infarto del miocardio e ictus cerebrale.
Studi anatomo-patologici e clinici hanno ormai chiarito che il rischio di rottura è legato più alle caratteristiche istomorfologiche della placca che alle sue dimensioni e al grado di stenosi luminale che essa provoca. Placche instabili sono caratterizzate da un grosso core lipidico, un cappuccio fibroso sottile, un ricco infiltrato di cellule infiammatorie macrofagiche e scarse cellule muscolari lisce. Negli ultimi due decenni, particolare attenzione è stata rivolta al concetto di "placca vulnerabile" come strumento per migliorare la stratificazione del rischio cardiovascolare e per portare, potenzialmente, a nuove opzioni terapeutiche invasive e non per prevenire e curare la malattia cardiovascolare aterotrombotica. È inoltre ipotizzabile che nei prossimi anni le nuove tecniche di imaging ad alta risoluzione saranno in grado di individuare le caratteristiche fondamentali che definiscono una placca vulnerabile che rischia di rompersi. Per ogni placca aterosclerotica potrebbe quindi essere generato un sistema di valutazione finalizzato a valutare il rischio specifico di instabilità con lo scopo di identificare prospetticamente gli eventi coronarici acuti. Inoltre, l'associazione di specifiche informazioni morfologiche con marcatori sistemici di vulnerabilità potrebbe consentire, in un prossimo futuro, di prevedere il rischio reale di infarto miocardico acuto per ogni singolo paziente
Discovery of cyanophage genomes which contain mitochondrial DNA polymerase
No full textDNA polymerase γ is a family A DNA polymerase responsible for the replication of mitochondrial DNA in eukaryotes. The origins of DNA polymerase γ have remained elusive because it is not present in any known bacterium, though it has been hypothesized that mitochondria may have inherited the enzyme by phage-mediated nonorthologous displacement. Here, we present an analysis of two full-length homologues of this gene which were found in the genomes of two bacteriophages which infect the chlorophyll-d containing cyanobacterium Acaryochloris marina. Phylogenetic analyses of these phage DNA polymerase γ proteins show they branch deeply within the DNA polymerase γ clade and therefore share a common origin with their eukaryotic homologues. We also found homologues of these phage polymerases in the environmental Community Cyberinfrastructure for Advanced Microbial Ecology Research and Analysis (CAMERA) database, which fell in the same clade. An analysis of the CAMERA assemblies containing the environmental homologues together with the filter fraction metadata indicated some of these assemblies may be of bacterial origin. We also show that the phage encoded DNA polymerase γ is highly transcribed as the
phage genomes are replicated. These findings provide data which may assist in reconstructing the evolution of mitochondria
Roland Barthes and Camera Lucida
No full textCamera Lucida, is often seen as the terminal point for a certain mode of thinking about photography, perceived as initiating the end of structuralism and an era of semiotics to be replaced by forms of new criticism. Camera Lucida was written in three months between 15 April and 3 June 1979. Printed in January 1980, the book was published before the road accident that knocked Barthes over on rue des Écoles, Paris, 25 February 1980. Barthes died a month later in hospital on 26 March 1980. Camera Lucida is an essay that belongs to this ‘poststructuralist’ context. It bears the hallmark of such concerns, a work that refuses to be ‘put in a box’. As part novel, part philosophy, part ‘biographeme’ (part author-object), the book eschews singular interpretations and offers a trap for those who try. However, the process of identifying the punctum in Camera Lucida proves to be difficult, fundamentally slippery
Characterization for high dynamic range imaging
No full textIn this paper we present a new practical camera characterization technique to improve color accuracy in high dynamic range (HDR) imaging. Camera characterization refers to the process of mapping device-dependent signals, such as digital camera RAW images, into a well-defined color space. This is a well-understood process for low dynamic range (LDR) imaging and is part of most digital cameras — usually mapping from the raw camera signal to the sRGB or Adobe RGB color space. This paper presents an efficient and accurate characterization method for high dynamic range imaging that extends previous methods originally designed for LDR imaging. We demonstrate that our characterization method is very accurate even in unknown illumination conditions, effectively turning a digital camera into a measurement device that measures physically accurate radiance values — both in terms of luminance and color — rivaling more expensive measurement instruments
Introduzione a Ritorno a Haifa; Umm Saad, due storie palestinesi (Nuova edizione)
No full textIn this presentation the author focuses the main characters of the two short novels by the prominent Arab writer Ghassan Kanafani (1936-1972)
Camera Botanica 1
No full textCamera Botanica 1 - testing a design process (unrealised buildings). ----------\ud
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Sited in a highly biodiverse and bushfire prone heathlands on the South-east coast of Western Australia, Camera Botanica 1 is a test of a new design methodology for achieving ecologically sustainable architecture in biodiverse, bushfire prone landscapes. ----------\ud
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The design methods were intensively site-based with the author-designer conducting his own site surveys using high-end professional grade surveying equipment such as: Real Time Kinematic GPS (landform survey); Terrestrial laser scanning (vegetation survey); laser levelling and Total Station surveys (erection of scaffolds and contour lines). ----------\ud
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This was the first time, internationally, that terrestrial laser scanning was used to measure vegetation. These precise surveys enabled the construction of highly detailed models and drawings - a facility that has not been available prior to this technology. ----------\ud
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Designed for a real client and a real site - Camera Botanica 1 is a hypothetical design outcome which demonstrates the efficacy of a new design methodology and thus expands on knowledge of the applicability of new surveying technologies to the design of ecologically sustainable architecture in biodiverse landscapes
Nuove acquisizioni sull'aterosclerosi: placca vulnerabile : relazione su invito
No full textNuove acquisizioni sull’aterosclerosi: la placca vulnerabile
Marina Camera
Dip. Scienze Farmacologiche, Università degli Studi di Milano e Centro Cardiologico Monzino IRCCS Milano.
L'aterosclerosi è una patologia infiammatoria, degenerativa, a lenta progressione, caratterizzata dalla presenza di placche aterosclerotiche che possono andare incontro a rottura. L’evento trombotico conseguente alla rottura della placca è responsabile degli eventi cardiovascolari, quali angina instabile, infarto del miocardio e ictus cerebrale.
Studi anatomo-patologici e clinici hanno ormai chiarito che il rischio di rottura è legato più alle caratteristiche istomorfologiche della placca che alle sue dimensioni e al grado di stenosi luminale che essa provoca. Placche instabili sono caratterizzate da un grosso core lipidico, un cappuccio fibroso sottile, un ricco infiltrato di cellule infiammatorie macrofagiche e scarse cellule muscolari lisce. Negli ultimi due decenni, particolare attenzione è stata rivolta al concetto di "placca vulnerabile" come strumento per migliorare la stratificazione del rischio cardiovascolare e per portare, potenzialmente, a nuove opzioni terapeutiche invasive e non per prevenire e curare la malattia cardiovascolare aterotrombotica. È inoltre ipotizzabile che nei prossimi anni le nuove tecniche di imaging ad alta risoluzione saranno in grado di individuare le caratteristiche fondamentali che definiscono una placca vulnerabile che rischia di rompersi. Per ogni placca aterosclerotica potrebbe quindi essere generato un sistema di valutazione finalizzato a valutare il rischio specifico di instabilità con lo scopo di identificare prospetticamente gli eventi coronarici acuti. Inoltre, l'associazione di specifiche informazioni morfologiche con marcatori sistemici di vulnerabilità potrebbe consentire, in un prossimo futuro, di prevedere il rischio reale di infarto miocardico acuto per ogni singolo paziente
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