Nuestros investigadores

Rocio Ramos Membrive

Publicaciones científicas más recientes (desde 2010)

Autores: Luis de Redín, Inés; Boiero, C.; Martínez-Oharriz, M.C.; et al.
Revista: INTERNATIONAL JOURNAL OF PHARMACEUTICS
ISSN 0378-5173  Vol. 541  Nº 1 - 2  2018  págs. 214 - 223
Bevacizumab-loaded nanoparticles (B-NP) were prepared by a desolvation process followed by freeze-drying, without any chemical, physical or enzymatic cross-linkage. Compared with typical HSA nanoparticles crosslinked with glutaraldehyde (B-NP-GLU), B-NP displayed a significantly higher mean size (310 nm vs. 180 nm) and a lower negative zeta potential (-15 mV vs. -36 mV). On the contrary, B-NP displayed a high payload of approximately 13% when measured by a specific ELISA, whereas B-NP-GLU presented a very low bevacizumab loading (0.1 mu g/mg). These results could be related to the inactivation of bevacizumab after reacting with glutaraldehyde. From B-NP, bevacizumab was released following an initial burst effect, proceeded by a continuous release of bevacizumab at a rate of 6 mu g/h. Cytotoxicity studies in ARPE cells were carried out at a single dose up to 72 h and with repeated doses over a 5-day period. Neither bevacizumab nor B-NP altered cell viability even when repeated doses were used. Finally, B-NP were labeled with Tc-99m and administered as eye drops in rats. Tc-99m-B-NP remained in the eye for at least 4 h while Tc-99m-HSA was rapidly drained from the administration point. In summary, HSA nanoparticles may be an appropriate candidate for ocular delivery of bevacizumab.
Autores: Collantes M; Quincoces, Gemma; et al.
Revista: THE QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING
ISSN 1824-4785  Vol. 61  Nº 4  2017  págs. 447 - 455
Background: The feasibility of beta cell mass (BCM) imaging and quantification with positron emission tomography (PET) in the pancreas is controversial. In an effort to shed some light on this topic, we have used a xenograft model of rat insulinoma (RIN) in mice, mimicking an intramuscular islet transplantation situation. Methods: A total of 105 RIN cells were subcutaneously implanted in nude mice (N.=8). Tumor size and glycaemia levels were determined daily. Rat C-peptide was measured to demonstrate rat insulin production. PET imaging with 11C-(+)-¿-dihydrotetrabenazine (11C-DTBZ) was done at 3 and 4 weeks and compared with 18F-FDG and 18F-DOPA studies in the same mice. Ex-vivo autoradiography with 11C-DTBZ was carried out in frozen sections of tumors. VMAT2 expression was measured by Western-blot and immunohistochemistry in tumors and RIN cells. Results: Functional rat insulin production in mice was demonstrated by substantial decrease in glycaemia (<50 mg/dL by week 4) and rat C-peptide levels (7.2±2.6 ng/mL) similar to those measured in control rats. PET studies showed that tumor imaging with 11C-DTBZ at four (N.=8) and five (N.=5) weeks was negative; only bigger tumors could be seen with 18F-DOPA. In explanted tumors 11C-DTBZ autoradiography was negative, albeit VMAT2 expression measured by Western-blot and immunohistochemistry was lower than in cultured RIN cells. Conclusions: Although insulinomas are fully functional it does not seem feasible to use 11C-DTBZ for in-vivo measuring of BCM. This might either be due to inherent technical limitations of PET, decrease in VMAT2 expression in the tumors due to unknown reasons, or other biological limiting facts.
Autores: Pastor, Y.; Camacho, Ana Isabel; Gil, Ana Gloria; et al.
Revista: JOURNAL OF MEDICAL MICROBIOLOGY
ISSN 0022-2615  Vol. 66  Nº 7  2017  págs. 946 - 958
Purpose. The aim of this study was to develop an immunogenic protective product against Shigella flexneri by employing a simple and safe heat treatment-based strategy. Methodology. The physicochemical characteristics of naturally produced (OMV) and heat-induced (HT) outer-membrane vesicles from S. flexneri were examined, including a comparison of the protein content of the products. Toxicological and biodistribution studies, and a preliminary experiment to examine the protective effectiveness of HT in a murine model of S. flexneri infection, were also included. Results. This method simultaneously achieves complete bacterial inactivation and the production of the HT vaccine product, leading to a safe working process. The obtained HT complex presented a similar morphology (electron microscopy) and chemical composition to the classical OMV, although it was enriched in some immunogens, such as lipoproteins, OmpA or OmpC, among others. The HT formulation was not toxic and biodistribution studies performed in mice demonstrated that the vaccine product remained in the small intestine after nasal administration. Finally, a single dose of HT administered nasally was able to protect mice against S. flexneri 2a. Conclusion. The convenient and safe manufacturing process, and the preliminary biological evaluation, support the use of the self-adjuvanted HT complex as a new vaccine candidate to face shigellosis. Further development is required, such as additional immune analyses, to evaluate whether this new subunit vaccine can be useful in achieving full protection against Shigella.
Autores: Guillen Valderrama, E; Díaz Perdigón, M.; García, Berta; et al.
Revista: REVISTA ESPAÑOLA DE MEDICINA NUCLEAR E IMAGEN MOLECULAR
ISSN 2253-654X  Vol. 36  Nº Supl 1  2017  págs. 16
Autores: García, Berta; Morales, María Isabel; Guillen Valderrama, E; et al.
Revista: EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING
ISSN 1619-7070  Vol. 43  Nº Supl.1.  2016  págs. S127 - S127
Autores: Ramos-Membrive, Rocio; Camacho, Ana Isabel; Quinoces, G.; et al.
Revista: EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING
ISSN 1619-7070  Vol. 43  2016  págs. S467 - S467
Autores: Ramos-Membrive, Rocio; Viedma, N.; Quincoces, Gemma; et al.
Revista: EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING
ISSN 1619-7070  Vol. 43  Nº Supl. 1  2016  págs. S465
Autores: Sancho, Lidia; Guillen Valderrama, E; Garcia-Velloso, Maria Jose; et al.
Revista: JOURNAL OF NUCLEAR MEDICINE
ISSN 0161-5505  Vol. 56  Nº Supl.3  2015  págs. 1273
Autores: Sancho, Lidia; Morán, Verónica; et al.
Revista: REVISTA ESPAÑOLA DE MEDICINA NUCLEAR E IMAGEN MOLECULAR
ISSN 2253-8070  Vol. 34  Nº Supl. 1  2015  págs. 59
La evaluación clínica del PET de amiloide con 18 F-florbetapir no se afecta por el tipo de equipo, aunque los de nueva generación reducen el número de casos dudosos. Para el seguimiento, los estudios deben ser adquiridos en un tiempo de adquisición similar. Estos hallazgos son relevantes para los ensayos de posibles nuevos fármacos anti-amiloid

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