ABSTRACT
We have developed novel gold-silver alloy nanoshells as magnetic resonance imaging (MRI) dual T1 (positive) and T2 (negative) contrast agents as an alternative to typical gadolinium (Gd)-based contrast agents. Specifically, we have doped iron oxide nanoparticles with Gd ions and sequestered the ions within the core by coating the nanoparticles with an alloy of gold and silver. Thus, these nanoparticles are very innovative and have the potential to overcome toxicities related to renal clearance of contrast agents such as nephrogenic systemic fibrosis. The morphology of the attained nanoparticles was characterized by XRD which demonstrated the successful incorporation of Gd(III) ions into the structure of the magnetite, with no major alterations of the spinel structure, as well as the growth of the gold-silver alloy shells. This was supported by TEM, ICP-AES, and SEM/EDS data. The nanoshells showed a saturation magnetization of 38 emu/g because of the presence of Gd ions within the crystalline structure with r1 and r2 values of 0.0119 and 0.9229 mL mg-1 s-1, respectively (Au:Ag alloy = 1:1). T1- and T2-weighted images of the nanoshells showed that these agents can both increase the surrounding water proton signals in the T1-weighted image and reduce the signal in T2-weighted images. The as-synthesized nanoparticles exhibited strong absorption in the range of 600-800 nm, their optical properties being strongly dependent upon the thickness of the gold-silver alloy shell. Thus, these nanoshells have the potential to be utilized for tumor cell ablation because of their absorption as well as an imaging agent.
ABSTRACT
La Tuberculosis Cerebral es la presentación más inusual de tuberculosis extrapulmonar en países en vías de desarrollo, donde esta enfermedad tiene alta incidencia y prevalencia. La amplia presentación clínica y poca especificidad, dificultan el diagnóstico precoz, relacionándose directamente con mayor morbimortalidad en pacientes afectados. La estereotaxia es una técnica neuroquirúrgica mínimamente invasiva que permite la localización y acceso preciso a estructuras intracraneanas. Se presenta un caso de una mujer de 34 años con clínica de crisis epilépticas y cuya imagenología muestra lesión parietal quística cerebral profunda. Debido a los múltiples diagnósticos diferenciales, se realiza biopsia-aspiración estereotáxica, llegando al diagnóstico de tuberculosis cerebral. El tratamiento adecuado muestra resolución completa del cuadro a los 8 meses.
Cerebral Tuberculosis is the most unusual presentation of extrapulmonary tuberculosis, in developing countries where this disease has high incidence and prevalence. The broad clinical presentation and poor specificity difficult early diagnosis, related directly with higher lethality in affected patients. Stereotactic is a modern neurosurgery minimally invasive that allows accurate localization and access to intracranial structures. Case of a 34 years-old woman with seizures and imagenology that present intraparietal cystic deep brain lesión. Due multiple differential diagnoses an aspiration-biopsy stereotactic is made, reaching the diagnostic of cerebral tuberculosis. Treatment after 8 months shows complete resolution.