Combined effects of prenatal inhibition of vasculogenesis and neurogenesis on rat brain development.

Malformations of cortical development (MCD) are one of the most common causes of neurological disabilities including autism and epilepsy. To disrupt cortical formation, methylazoxymethanol (MAM) or thalidomide (THAL) has been used to affect neurogenesis or vasculogenesis. Although previous models of MCD have been useful, these models primarily attack a single aspect of cortical development.

Early cerebrovascular and parenchymal events following prenatal exposure to the putative neurotoxin methylazoxymethanol.

One of the most common causes of neurological disabilities are malformations of cortical development (MCD). A useful animal model of MCD consists of prenatal exposure to methylazoxymethanol (MAM), resulting in a postnatal phenotype characterized by cytological aberrations reminiscent of human MCD. Although postnatal effects of MAM are likely a consequence of prenatal events, little is known on how the developing brain reacts to MAM.

Seizure-promoting effect of blood-brain barrier disruption.

Purpose: It is generally accepted that blood-brain barrier (BBB) failure occurs as a result of CNS diseases, including epilepsy. However, evidences also suggest that BBB failure may be an etiological factor contributing to the development of seizures.

Methods: We monitored the onset of seizures in patients undergoing osmotic disruption of BBB (BBBD) followed by intraarterial chemotherapy (IAC) to treat primary brain lymphomas.

In vitro responsiveness of human-drug-resistant tissue to antiepileptic drugs: insights into the mechanisms of pharmacoresistance.

Pharmacoresistance in epileptic patients may be ascribed to at least two, not mutually exclusive, mechanisms: a pharmacokinetic mechanism and a decreased sensitivity or availability of targets to antiepileptic drugs (AEDs; i.e., carbamazepine and phenytoin (CBZ, PHT)).

Alternating current electrical stimulation enhanced chemotherapy: a novel strategy to bypass multidrug resistance in tumor cells.

Background: Tumor burden can be pharmacologically controlled by inhibiting cell division and by direct, specific toxicity to the cancerous tissue. Unfortunately, tumors often develop intrinsic pharmacoresistance mediated by specialized drug extrusion mechanisms such as P-glycoprotein. As a consequence, malignant cells may become insensitive to various anti-cancer drugs.

RLIP76, a non-ABC transporter, and drug resistance in epilepsy.

Background: Permeability of the blood-brain barrier is one of the factors determining the bioavailability of therapeutic drugs and resistance to chemically different antiepileptic drugs is a consequence of decreased intracerebral accumulation. The ABC transporters, particularly P-glycoprotein, are known to play a role in antiepileptic drug extrusion, but are not by themselves sufficient to fully explain the phenomenon of drug-resistant epilepsy. Proteomic analyses of membrane protein differentially expressed in epileptic foci brain tissue revealed the frequently increased expression of RLIP76/RALBP1, a recently described non-ABC multi-specific transporter.

Very low intensity alternating current decreases cell proliferation.

Electric fields impact cellular functions by activation of ion channels or by interfering with cell membrane integrity. Ion channels can regulate cell cycle and play a role in tumorigenesis. While the cell cycle may be directly altered by ion fluxes, exposure to direct electric current of sufficient intensity may decrease tumor burden by generating chemical products, including cytotoxic molecules or heat.

Significance of MDR1 and multiple drug resistance in refractory human epileptic brain.

Background: The multiple drug resistance protein (MDR1/P-glycoprotein) is overexpressed in glia and blood-brain barrier (BBB) endothelium in drug refractory human epileptic tissue. Since various antiepileptic drugs (AEDs) can act as substrates for MDR1, the enhanced expression/function of this protein may increase their active extrusion from the brain, resulting in decreased responsiveness to AEDs.

Methods: Human drug resistant epileptic brain tissues were collected after surgical resection.

Peripheral markers of blood-brain barrier damage.

Neurological diseases are often associated with cerebrovascular dysfunction and changes in blood-brain barrier (BBB) function. This is important for two seemingly conflicting reasons. On the one hand, a leaky BBB may lead to brain disease by allowing extravasation of cells and molecules normally segregated in the periphery, while on the other hand an intact BBB may hamper drug delivery to the ailing brain.

Glycerophosphoinositol and dexamethasone improve transendothelial electrical resistance in an in vitro study of the blood-brain barrier.

The blood-brain barrier (BBB) maintains the homeostasis of the brain microenvironment, which is crucial for neuronal activity and function. Under pathological conditions, the BBB may fail due to yet unknown mechanisms. BBB failure is accompanied by an increase in the transendothelial permeability to substances such as sucrose that are normally extruded.