1,720,958 research outputs found
Applicazione di Gel piastrinico in chirurgia ortopedica.
No full textPremessa: In questo studio abbiamo applicato il gel piastrinico (Gp) alle seguenti patologie ortopediche: reimpianto di protesi d’anca dopo mobilizzazione asettica, protesi di ginocchio a fissazione biologica, perdita di sostanza ossea, ritardo di ossificazione in corso di allungamento osseo e pseudoartrosi da causa biologica.
Si è proceduto alla scelta dei pazienti basandosi sui dati presenti in letteratura riguardanti studi preliminari e meccanismo d’azione dei fattori di crescita (GFs). L’applicazione locale in forma di gel garantisce la permanenza dei GFs nella sede di lesione evitandone la dispersione. I GFs agiscono in concerto tra di loro ed inoltre potenziano l’azione di GFs prodotti spontaneamente dalle cellule coinvolte nel processo di riparazione e rigenerazione ossea.
Materiali e Metodi: il metodo di preparazione del Gp prevede un prelievo di 450 cc di sangue intero e l’ottenimento di plasma ricco di piastrine (PRP) e plasma povero di piastrine (PPP). Dal PPP viene ottenuto il crioprecipitato. Si procede poi alla miscelazione di Cp e crio con produzione di un mix di volume finale di 30 ml che viene congelato a - 80 °C.
Al momento dell’applicazione il mix viene attivato a gel tramite l’uso di trombina autologa e calcio gluconato con i seguenti rapporti: 5 parti di mix, 1 parte di trombina, 1 parte di calcio gluconato.
Da Febbraio 2004 a Dicembre 2005, 129 pazienti sono stati sottoposti ad intervento chirurgico con applicazione di circa 30 ml di Gp da solo o in associazione ad osso autologo, omologo o a preparati osteoconduttivi sintetici. Il follow-up dei pazienti prevede controllo radiologico a 1, 6 e 12 mesi. La sintomatologia dolorosa viene monitorata tramite la scala analogica visiva (VAS).
Risultati: 50 pazienti hanno completato il follow-up ad 1 anno dall’intervento. Nel 96% dei casi si sono evidenziate, radiologicamente, l’assenza di riassorbimento osseo ed una precoce osteointegrazione che confermano il ruolo osteoinduttivo del Gp. In due pazienti (4%), affetti da perdita di sostanza ossea, l’insuccesso dell’applicazione del Gp è attribuibile all’instabilità dei mezzi di sintesi utilizzati per ridurre il focolaio di frattura.
Nei Gp applicati la concentrazione piastrinica media è risultata di 3363.1x103/ ml, (range 756,0 – 9741,0) con un coefficiente di concentrazione di 14.68.
Discussione: In tutti i pazienti trattati il Gp è risultato un valido aiuto nella procedura chirurgica e nel decorso post-operatorio con i seguenti vantaggi: l’utilizzo di una minor quantità di osso, l’assenza di complicanze flogistiche e di intolleranze, una rapida guarigione delle ferite chirurgiche, una riduzione del sanguinamento e quindi un minor ricorso alla trasfusione di sangue omologo, una riduzione del dolore, una più rapida ripresa funzionale e, al momento attuale, l’assenza di segnalazioni di non-responder
An update on Xenotransplantation
No full textXenotransplantation is one of the possible avenues currently being explored to address the shortage problem of human organs. With this in mind, this article will briefly review the current situation with respect to the immunological, physiological and biosafety aspects related to the transplantation of pig organs into primates. Acute humoral xenograft rejection (AHXR) currently remains the central immunological obstacle and the development of strategies for both a better control of the elicited anti-pig humoral immune response or the prevention of the onset of coagulation disorders that accompany AHXR are the two primary focuses of research. To date, porcine xenografts have been shown to sustain the life of nonhuman primates for several months. Such preclinical studies have also demonstrated the absence of insurmountable physiological incompatibilities between pig and primate. In addition, reassuring findings regarding biosafety aspects have been generated and pro-active research aimed at the identification of an organ source with a higher safety profile is also underway. These advancements, in conjunction with ongoing research in pig genetic engineering, immunosuppression and tolerance are expected to further extend the survival of porcine xenografts transplanted into primates. However, until further physiological, efficacy and safety data are generated in relevant primate models, clinical xenotransplantation should not be considered
Refinement of a transplantation project in the non-human primate by the use of a humane endpoint.
No full textAn assessment scheme was developed to establish a humane endpoint in a pig-to-primate renal xenotransplantation project, with a view to minimizing and controlling any pain or suffering conditions in the animals involved while still achieving the scientific objective. In particular, the assessment criteria for identifying the earliest endpoint are described, bearing in mind both the researcher's need to obtain top-quality data and the ethical need to safeguard the animals. The scheme should also be applicable to other experiments involving non-human primates (e.g. allotransplantation, survival after major surgery, pharmacological safety tests) because it considers reproducible general parameters together with aspects specific to each experimental model
Messa a punto e standardizzazione della metodica di preparazione del Gel piastrinico autologo per applicazioni in chirurgia ortopedica.
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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