1,720,970 research outputs found
Ingegnerizzazione di cellule T con un recettore chimerico anti-hPSMA per l'immunoterapia adottiva del carcinoma prostatico
Full text linkThe genetic transfer of antigen receptors is a powerful approach to rapidly generate tumor-specific T lymphocytes to be employed in adoptive cell therapy (ACT) protocols. Differently from the physiological T-cell receptor, chimeric antigen receptors (CARs) encompass antigen recognition moieties, mainly derived from immunoglobulin variable regions, and activating domains derived from the TCR complex. This artificial structure combines the effector functions of T lymphocytes with the ability of antibodies to recognize surface antigens with high specificity and independently of antigen processing or MHC-restricted presentation.
During my Ph.D., I developed a second generation CAR containing both TCR and CD28 signalling moieties fused to a scFv targeting the human Prostate Specific Membrane Antigen (hPSMA), to engineer human PBMCs for the immunotherapy of prostate cancer. Instead of the most widely used oncoretroviral vectors we propose lentiviral vectors (LV) as an alternative gene transfer method, because of the ability to efficiently transduce even less activated or nondividing T cells. Moreover, the presence of a synthetic bidirectional promoter in the vector design for the coordinate expression of both CAR and Firefly Luciferase, enabled the in vivo monitoring of distribution and homing properties of adoptively transferred T cells with bioluminescence imaging (BLI).
The resulting population of CAR-engineered T cells (T-bodies) showed high level of CAR expression (more than 50% of cells), together with a memory phenotype and the ability to efficiently kill PSMA-expressing cells. The in vivo transfer in a subcutaneous model of prostate carcinoma demonstrated the T-bodies' anti-tumor efficacy upon local delivery, but highlighted the therapeutic failure of their systemic infusion. Data from BLI revealed the limited persistence of transferred T cells and their inability to efficiently reach the tumor.
Our findings support the feasibility of LV vectors as a valid and safe tool to engineer T cells with chimeric antigen receptors; the anti-tumor efficacy of lymphocytes endowed with second generation CARs constitutes a rationale for further studies and potential clinical application of the approach, but there is still the absolute need to improve persistence, survival and homing properties of infused T cells in order to get positive therapeutic results.Nell'ambito dell'immunoterapia cellulare adottiva, l’ingegnerizzazione di linfociti T con recettori diretti contro antigeni tumorali rappresenta un'efficace strategia per generare in tempi rapidi un elevato numero di linfociti tumore-specifici. In alternativa al TCR fisiologico, la cellula T può essere ingegnerizzata con recettori chimerici per l'antigene (CAR) costituiti da un dominio di riconoscimento antigenico (derivato da anticorpi monoclonali) fuso a domini di trasduzione del segnale derivati dal complesso TCR: questo tipo di struttura combina la specificità del riconoscimento anticorpale (MHC-indipendente) con le potenzialità anti-tumorali dei linfociti T.
L’attività di ricerca svolta nel mio corso di Dottorato si è focalizzata sullo sviluppo di un protocollo per la generazione di linfociti T ingegnerizzati con un CAR di seconda generazione (scFv-CD28-CD3ζ) diretto contro l'antigene hPSMA (Prostate Specific Membrane Antigen) per il trattamento del carcinoma prostatico.
L'utilizzo di vettori lentivirali (LV) come alternativa ai più diffusi vettori oncoretrovirali, consente di trasdurre in modo efficace cellule T scarsamente differenziate, con positive implicazioni sulla loro funzionalità in vivo; in questo studio, inoltre, la presenza nel vettore LV di un promotore bidirezionale recentemente descritto ha permesso l'espressione coordinata del CAR e del gene reporter Firefly Luciferase con l'obiettivo di monitorare il destino biologico dei linfociti trasferiti adottivamente in vivo, mediante imaging di bioluminescenza (BLI).
La popolazione di PBMC ingegnerizzati con recettore chimerico (T-body) è caratterizzata da un'elevata percentuale di espressione del CAR anti-hPSMA (superiore al 50%), da un fenotipo di memoria e dalla capacità di riconoscere e lisare in modo specifico cellule esprimenti l'antigene. In un modello murino di tumore prostatico sottocutaneo i T-body si sono dimostrati efficaci solo se co-inoculati con cellule tumorali o se inoculati a livello locale, mentre il trasferimento adottivo per via sistemica non ha determinato alcun risultato terapeutico. Il monitoraggio della distribuzione in vivo dei linfociti mediante BLI ha indicato come la scarsa capacità di sopravvivenza e di homing al sito tumorale possano essere una potenziale causa del fallimento terapeutico.
I risultati positivi ottenuti in questo lavoro, in particolare lo sviluppo di un recettore chimerico anti-hPSMA di seconda generazione, l'utilizzo di vettori LV e la generazione di T-body funzionali in vitro e in vivo, costituiscono il razionale per ulteriori studi e per future applicazioni cliniche di questo tipo di approccio in pazienti con carcinoma prostatico; rimane tuttavia fondamentale chiarire le dinamiche di ricircolazione e distribuzione delle cellule T con l'obiettivo di implementarne la capacità di sopravvivere, ricircolare e raggiungere il sito tumorale, fattori indispensabili per mediare l'effettiva regressione della neoplasia
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Evaluation of the in vivo fate and targeting potentials of avidin-nucleic-acid nano-assemblies.
No full textAVIDIN-NUCLEIC-ACID NANO-ASSEMBLIES AS MULTIVALENT, TUNABLE AND BIOCOMPATIBLE DRUG DELIVERY TOOLS
No full textBiokinetic and dosimetric studies of Re-188-hyaluronic acid: a new radiopharmaceutical for treatment of hepatocellular carcinoma
No full textHepatocellular carcinoma (HCC) is the most common primary liver cancer and has very limited therapeutic options. Recently, it has been found that hyaluronic acid (HA) shows selective binding to CD44 receptors expressed in most cancer histotypes. Since the trend in cancer treatment is the use of targeted radionuclide therapy, the aim of this research was to label HA with rhenium-188 and to evaluate its potential use as a hepatocarcinoma therapeutic radiopharmaceutical.
METHODS: (188)Re-HA was prepared by a direct labelling method to produce a ReO(O-COO)(2)-type coordination complex. (188)Re-HA protein binding and its stability in saline, phosphate buffer, human serum and cysteine solutions were determined. Biokinetic and dosimetric data were estimated in healthy mice (n=60) using the Medical Internal Radiation Dose methodology and mouse model beta-absorbed fractions. To evaluate liver toxicity, alanine aminotranferase (AST) and aspartate aminotranferase (ALT) levels in mice were assessed and the liver maximum tolerated dose (MTD) of (188)Re-HA was determined.
RESULTS: A stable complex of (188)Re-HA was obtained with high radiochemical purity (>90%) and low serum protein binding (2%). Biokinetic studies showed a rapid blood clearance (T(1/2)alpha=21 min). Four hours after administration, (188)Re-HA was almost totally removed from the blood by the liver due to the selective uptake via HA-specific receptors (73.47+/-5.11% of the injected dose). The liver MTD in mice was approximately 40 Gy after 7.4 MBq of (188)Re-HA injection.
CONCLUSIONS: (188)Re-HA complex showed good stability, pharmacokinetic and dosimetric characteristics that confirm its potential as a new agent for HCC radiation therapy
A paclitaxel-hyaluronan bioconjugate exerts a high in vivo therapeutic activity against ovarian cancer
No full textPurpose: This study was designed to evaluate the pharmacologic and biological properties of a paclitaxel-hyaluronan bioconjugate (ONCOFID-P) against IGROV-1 and OVCAR-3 human ovarian cancer xenografts following i.p. administration.
Experimental design: In vitro tumor sensitivity to ONCOFID-P was analyzed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, whereas bioconjugate interaction with cells was studied cytofluorimetrically and by confocal microscopy. In vivo toxicity was assessed by a single-dose maximum-tolerated dose, peripheral blood cell count determination and by histologic analysis. Biodistribution of the compound was evaluated with a small animal-dedicated scintigraphy gamma camera following injection of 99mTc-labeled ONCOFID-P. Pharmacokinetic analysis was also carried out. Female severe combined immunodeficiency mice implanted with ovarian cancer cells underwent treatment with ONCOFID-P or free paclitaxel starting from day 7 or 14 after tumor injection, and survivals were compared.
Results: ONCOFID-P interacted with CD44, entered cells through a receptor-mediated mechanism, and exerted a concentration-dependent inhibitory effect against tumor cell growth. After i.p. administration, the bioconjugate distributed quite uniformly within the peritoneal cavity, was well-tolerated, and was not associated with local histologic toxicity. Pharmacokinetic studies revealed that blood levels of bioconjugate-derived paclitaxel were much higher and persisted longer than those obtained with the unconjugated free drug. Intraperitoneal treatment of tumor-bearing mice with the bioconjugate revealed that ONCOFID-P exerted a relevant increase in therapeutic activity compared with free drug.
Conclusions: ONCOFID-P significantly improved results obtained with conventional paclitaxel, in terms of in vivo tolerability and therapeutic efficacy; these data strongly support its development for locoregional treatment of ovarian cancer
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
- …
