Drug Delivery Nanosystems for the Localized Treatment of Glioblastoma Multiforme

Glioblastoma multiforme is one of the most prevalent and malignant forms of central nervous system tumors. The treatment of glioblastoma remains a great challenge due to its location in the intracranial space and the presence of the blood⁻brain tumor barrier. There is an urgent need to develop novel therapy approaches for this tumor, to improve the clinical outcomes, and to reduce the rate of recurrence and adverse effects associated with present options. The formulation of therapeutic agents in nanostructures is one of the most promising approaches to treat glioblastoma due to the increased availability at the target site, and the possibility to co-deliver a range of drugs and diagnostic agents. Moreover, the local administration of nanostructures presents significant additional advantages, since it overcomes blood⁻brain barrier penetration issues to reach higher concentrations of therapeutic agents in the tumor area with minimal side effects. In this paper, we aim to review the attempts to develop nanostructures as local drug delivery systems able to deliver multiple agents for both therapeutic and diagnostic functions for the management of glioblastoma.

Glass–glass ceramic thermoseeds for hyperthermic treatment of bone tumors

Implantable thermoseeds are synthesised from mixtures of a melt-derived glass with composition SiO(2) (40)-CaO(40)-Fe(2)O(3)(20) (mol%) and a sol-gel glass with composition SiO(2)(58)-P(2)O(5)(6)-CaO(36) (mol%). Structural, textural and magnetic properties of the samples are evaluated. In vitro bioactivity is assessed in order to determine the potential capability to bond to living bone. In spite of the low textural properties of the material, a bioactive behavior is observed as a result of the sol-gel glass content. Although the crystallization of the glass ceramic provides the magnetic phase, the presence of sol-gel glass modifies the magnetic properties, improving the heating power. For the first time, hyperthermia heating experiments as well as preliminary biocompatibility assays have been carried out for this kind of material. The ability to reach hyperthermic temperature range together with the bioactive behavior makes this biomaterial a very promising candidate for bone cancer treatment.

Closed-loop control of renal perfusion pressure in physiological experiments

This paper presents the design, experimental modeling, and control of a pump-driven renal perfusion pressure (RPP)-regulatory system to implement precise and relatively fast RPP regulation in rats. The mechatronic system is a simple, low-cost, and reliable device to automate the RPP regulation process based on flow-mediated occlusion. Hence, the regulated signal is the RPP measured in the left femoral artery of the rat, and the manipulated variable is the voltage applied to a dc motor that controls the occlusion of the aorta. The control system is implemented in a PC through the LabView software, and a data acquisition board NI USB-6210. A simple first-order linear system is proposed to approximate the dynamics in the experiment. The parameters of the model are chosen to minimize the error between the predicted and experimental output averaged from eight input/output datasets at different RPP operating conditions. A closed-loop servocontrol system based on a pole-placement PD controller plus dead-zone compensation was proposed for this purpose. First, the feedback structure was validated in simulation by considering parameter uncertainty, and constant and time-varying references. Several experimental tests were also conducted to validate in real time the closed-loop performance for stepwise and fast switching references, and the results show the effectiveness of the proposed automatic system to regulate the RPP in the rat, in a precise, accurate (mean error less than 2 mmHg) and relatively fast mode (10-15 s of response time).