Publications by authors named "Luis-Alberto Medina"

The E6 and E7 oncoproteins of high-risk types of human papillomavirus (HR-HPV) are crucial for the development of cervical cancer (CC). Small interfering RNAs (siRNAs) are explored as novel therapies that silence these oncogenes, but their clinical use is hampered by inefficient delivery systems. Modification (pegylation) with polyethylene glycol (PEG) of liposomal siRNA complexes (siRNA lipoplexes) may improve systemic stability.

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Purpose: To evaluate the effect of reconstruction and noise removal algorithms on the accuracy and precision of iodine concentration (C) quantified with subtracted micro-computed tomography (micro-CT).

Procedures: Two reconstruction algorithms were evaluated: a filtered backprojection (FBP) algorithm and a simultaneous iterative reconstruction technique (SIRT) algorithm. A 3D bilateral filter (BF) was used for noise removal.

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Colorectal cancer (CRC) is one of the top five cancers in incidence and mortality worldwide. The early detection of this neoplasm through analysis of circulating free DNA (cfDNA), which carries tumor genetic alterations, as a liquid biopsy, could have a major impact in enhancing early detection and reducing the mortality rate. The aim of this work was to demonstrate the feasibility of using cfDNA as a liquid biopsy for the early detection of CRC.

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In the present work, we propose the development of a novel carrier that does not need organic solvents for its preparation and with the potential for the intravenous delivery of lipophilic and hydrophilic drugs. Named lipomics, this is a mixed colloid of micelles incorporated within a liposome. This system was designed through ternary diagrams and characterized by physicochemical techniques to determine the particle size, zeta potential, shape, morphology, and stability properties.

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Spinal cord injury (SCI) refers to the damage suffered in the spinal cord by any trauma or pathology. The purpose of this work was to determine whether Tc-GA-5, a radiotracer targeting Glial Fibrillary Acidic Protein (GFAP), can reveal in vivo the reactivation of astrocytes in a murine model with SCI. A method for the Tc radiolabeling of the mouse anti-GFAP monoclonal antibody GA-5 was implemented.

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The aim of this work was to systematically obtain quantitative imaging parameters with static and dynamic contrast-enhanced (CE) X-ray imaging techniques and to evaluate their correlation with histological biomarkers of angiogenesis in a subcutaneous C6 glioma model. Enhancement (E), iodine concentration (C), and relative blood volume (rBV) were quantified from single- and dual-energy (SE and DE, respectively) micro-computed tomography (micro-CT) images, while rBV and volume transfer constant (K) were quantified from dynamic contrast-enhanced (DCE) planar images. C and rBV allowed a better discernment of tumor regions from muscle than E in SE and DE images, while no significant differences were found for rBV and K in DCE images.

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Cervical cancer is usually diagnosed in the later stages despite many campaigns for early detection and continues to be a major public health problem. The standard treatment is cisplatin-based chemotherapy plus radiotherapy, but patient response is far from ideal. In the research for new drugs that enhance the activity of cisplatin, different therapeutic agents have been tested, among them the antiprogestin mifepristone.

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In the last two decades, alginate scaffolds have been variously studied as extracellular matrix analogs for tissue engineering. However, relevant evidence is still lacking concerning their ability to mimic the microenvironment of hierarchical tissues such as bone. Hence, an increasing amount of attention has recently been devoted to the fabrication of macro/microporous sponges with pore anisotropy able to more accurately replicate the cell niche structure as a trigger for bioactive functionalities.

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Goal: Evaluate bone regeneration in a critical size bone defect model in the jaw of healthy rats as a function of gender and defect location.

Design: A series of microCT and histological studies were performed to evaluate the process of bone regeneration in rats with a mandibular critical size defect. Rats were placed in two groups according to gender and sorted in terms of bone defect location.

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Background: The GTPase KRas4B has been utilized as a principal target in the development of anticancer drugs. PDE6δ transports KRas4B to the plasma membrane, where it is released to activate various signaling pathways required for the initiation and maintenance of cancer. Therefore, identifying new small molecules that prevent activation of this GTPase by stabilizing the KRas4B-PDE6δ molecular complex is a practical strategy to fight against cancer.

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Malignant pleural mesothelioma (MPM) is the most common tumor of the pulmonary pleura. It is a rare and aggressive malignancy, generally associated with continuous occupational exposure to asbestos. Only a multimodal-approach to treatment, based on surgical resection, chemotherapy and/or radiation, has shown some benefits.

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A novel targeted drug delivery nanoparticle system based on poly(D,L-lactide-co-glycolide) acid (PLGA) for delivery of doxorubicin (DOX) was developed. DOX-PLGA NPs were obtained by the emulsification-solvent evaporation technique. Then, their surface was modified with poly(L-γ-glutamic acid) (γ-PGA) and finally conjugated to modified folic acid (FA) as a targeting ligand.

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In this paper, we report the conjugation of the humanized monoclonal antibody nimotuzumab with cisplatin-loaded liposomes and the in vitro evaluation of its affinity for tumor cells. The conjugation procedure was performed through derivatization of nimotuzumab with N-succinimidyl S-acetylthioacetate (SATA) followed by a covalent attachment with maleimide groups at the end of PEG-DSPE chains located at the membrane of pre-formed liposomes. Confocal microscopy was performed to evaluate the immunoliposome affinity for EGFR antigens from human epidermoid carcinoma (A-431) and normal lung (MRC-5) cell lines.

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The venom of the Eastern coral snake Micrurus fulvius can cause respiratory paralysis in the bitten patient, which is attributable to β-neurotoxins (β-NTx). The aim of this work was to study the biodistribution and lymphatic tracking by molecular imaging of the main β-NTx of M. fulvius venom.

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Research on oncolytic viruses has mostly been directed towards the treatment of solid tumors, which has yielded limited information regarding their activity in hematological cancer. It has also been directed towards the treatment of humans, yet veterinary medicine may also benefit. Several strains of the Newcastle disease virus (NDV) have been used as oncolytics in vitro and in a number of in vivo experiments.

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Background: There are currently no available biomarkers for advanced pleural mesothelioma that determine which patients could benefit from a specific chemotherapy regimen.

Methods: Based on the results of a previously published phase II study, we associated the (99m)Technetium-labelled liposomal doxorubicin ((99m)Tc-LD) uptake value (75 % cut-off) with the response rate, progression-free survival and overall survival of patients treated with a combination of liposomal doxorubicin and cisplatin.

Results: Patients with tumours exhibiting increased (99m)Tc-LD uptake showed better response rates, progression-free survival and overall survival than those exhibiting lower uptake 73.

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Background: We have investigated the ability of Mifepristone, an anti-progestin and anti-glucocorticoid drug, to modulate the antitumor effect of current standard clinical treatment in glioblastoma xenografts.

Methods: The effect of radiation alone or combined with Mifepristone and Temozolamide was evaluated on tumor growth in glioblastoma xenografts, both in terms of preferentially triggering tumor cell death and inhibiting angiogenesis. Tumor size was measured once a week using a caliper and tumor metabolic-activity was carried out by molecular imaging using a microPET/CT scanner.

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Unlabelled: The aim of this study was to evaluate the volume-of-interest (VOI) technique in the measurement of volume radioactivity and in the differentiation of necrotic sites from residual tumor activity in a phantom.

Methods: PET/CT was performed on a phantom filled with (18)F-FDG solution at different concentrations. The VOI was quantified in 2 sessions to evaluate the VOI measurements as a function of activity concentration in the phantom.

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Background: We explore the use of a clinical orthovoltage X-ray treatment unit as a small-animal radiation therapy system in a tumoral model of cervical cancer.

Methods: Nude mice were subcutaneously inoculated with 5 x 106 HeLa cells in both lower limbs. When tumor volume approximated 200 mm3 treatment was initiated.

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