Search results for "Blood–brain barrier"
showing 10 items of 134 documents
Small rises in plasma choline reverse the negative arteriovenous difference of brain choline.
1990
The concentrations of free choline in blood plasma from a peripheral artery and from the transverse sinus, in the CSF, and in total brain homogenate, have been measured in untreated rats and in rats after acute intraperitoneal administration of choline chloride. In untreated rats, the arteriovenous difference of brain choline was related to the arterial choline level. At low arterial blood levels (less than 10 microM) as observed under fasting conditions, the arteriovenous difference was negative (about -2 microM), indicating a net release of choline from the brain of about 1.6 nmol/g/min. In rats with spontaneously high arterial blood levels (greater than 15 microM), the arteriovenous diff…
Uptake and storage of choline by rat brain: influence of dietary choline supplementation.
1991
In order to elucidate the regulation of the levels of free choline in the brain, we investigated the influence of chronic and acute choline administration on choline levels in blood, CSF, and brain of the rat and on net movements of choline into and out of the brain as calculated from the arteriovenous differences of choline across the brain. Dietary choline supplementation led to an increase in plasma choline levels of 50% and to an increase in the net release of choline from the brain as compared to a matched group of animals which were kept on a standard diet and exhibited identical arterial plasma levels. Moreover, the choline concentration in the CSF and brain tissue was doubled. In th…
NMDA receptor antagonist felbamate reduces behavioral deficits and blood-brain barrier permeability changes after experimental subarachnoid hemorrhag…
2007
Increased levels of glutamate and aspartate have been detected after subarachnoid hemorrhage (SAH) that correlate with neurological status. The NMDA receptor antagonist felbamate (FBM; 2-phenyl-1,3-propanediol dicarbamate) is an anti-epileptic drug that elicits neuroprotective effects in different experimental models of hypoxia-ischemia. The aim of this dose-response study was to evaluate the effect of FBM after experimental SAH in rats on (1) behavioral deficits (employing a battery of assessment tasks days 1-5 post-injury) and (2) blood-brain barrier (BBB) permeability changes (quantifying microvascular alterations according to the extravasation of protein-bound Evans Blue by a spectropho…
Distigmine bromide induced acute psychotic disorder in a patient with multiple sclerosis.
2003
AbstractA female patient with multiple sclerosis (MS) suffered from an acute psychotic disorder after taking distigmine bromide for detrusor dysfunction. She showed a dramatic relief of her symptoms after the medication, distigmine bromide, was stopped. Distigmine is not supposed to penetrate the blood-brain barrier (BBB). However, in MS patients a leakage of the BBB could be hypothesized.
N-valproyl-L-tryptophan for CNS-targeting: synthesis, characterization and efficacy in vitro studies of a new potential antiepileptic drug.
2010
A new aminoacidic derivative of valproic acid (VPA) has been synthesized and characterized by analytical and spectral data. The rationale for the preparation of such potential antiepileptic agent is based on the observation that chemical combination of the anticonvulsant pharmacophore, VPA with essential aminoacids could afford more effective and less toxic actives. The synthesis, characterization, physico-chemical parameters functional for crossing Blood Brain Barrier of N-valproyl-L-tryptophan (4) are reported. The Log D pH7.4 (0.3) indicates that (4) is adequate to cross biological membranes. Its chemical and enzymatic stability were assessed. The experiments indicate high stability of c…
Ionizing radiation-engineered nanogels as insulin nanocarriers for the development of a new strategy for the treatment of Alzheimer's disease
2016
A growing body of evidence shows the protective role of insulin in Alzheimer's disease (AD). A nanogel system (NG) to deliver insulin to the brain, as a tool for the development of a new therapy for Alzheimer's Disease (AD), is designed and synthetized. A carboxyl-functionalized poly(N-vinyl pyrrolidone) nanogel system produced by ionizing radiation is chosen as substrate for the covalent attachment of insulin or fluorescent molecules relevant for its characterization. Biocompatibility and hemocompatibility of the naked carrier is demonstrated. The insulin conjugated to the NG (NG-In) is protected by protease degradation and able to bind to insulin receptor (IR), as demonstrated by immunofl…
Blood-Brain-Barrier Models for the Investigation of Transporter- and Receptor-Mediated Amyloid-β Clearance in Alzheimers Disease
2010
Alzheimer's disease (AD) is the most common form of dementia in the elderly with more than 26 million people worldwide living with the disease. Besides the main neuropathological hallmarks of AD, provoked by the accumulation of amyloid-β (Aβ) and tau hyperphosphorylation, other cells and cellular systems such as microglia and the neurovascular unit establishing the blood-brain-barrier (BBB) have been implicated to play a role in AD etiopathology. Insulating the brain from the blood stream, the BBB facilitates supply and disposal of nutrients and metabolites by the expression of transporters and transcytotic receptors at the polarized endothelial cell (EC) surface. Recently, several proteins…
Structure, interdomain dynamics, and pH-dependent autoactivation of pro-rhodesain, the main lysosomal cysteine protease from African trypanosomes
2021
AbstractRhodesain is the lysosomal cathepsin L-like cysteine protease ofT. brucei rhodesiense, the causative agent of Human African Trypanosomiasis. The enzyme is essential for the proliferation and pathogenicity of the parasite as well as its ability to overcome the blood-brain barrier of the host. Lysosomal cathepsins are expressed as zymogens with an inactivating pro-domain that is cleaved under acidic conditions. A structure of the uncleaved maturation intermediate from a trypanosomal cathepsin L-like protease is currently not available. We thus established the heterologous expression ofT. brucei rhodesiensepro-rhodesain inE. coliand determined its crystal structure. The trypanosomal pr…
Redistribution of aquaporin-4 in human glioblastoma correlates with loss of agrin immunoreactivity from brain capillary basal laminae
2003
Vasogenic edema is one of the most serious clinical problems in brain tumors and tightly connected to water shifts between the different fluid compartments in the brain. Aquaporin water channels have been recognized to have an important impact on the development of edematous swelling in the brain. Astrocytes, which are believed to induce or at least maintain the blood-brain barrier in the brain capillary endothelial cells, express the aquaporin isoform AQP4. Normally, AQP4 is highly concentrated in the glial membrane where astrocytes contact mesenchymal space, such as perivascular or brain superficial regions. Parenchymal membranes do not show any immunocytochemical AQP4-specific signal. We…
Cell Culture Systems for Studying Biomaterial Interactions with Biological Barriers
2011
The human body has numerous physical barriers that prevent most harmful or foreign compounds from entering the body. These barriers are formed by unique cell types, which through their location-specific biological cell characteristics prevent compounds from passing between or through them or selectively allow only specific compounds to move across the barrier that they form. Multiple cell types are involved that together form the functioning barrier in a particular organ or tissue. In many cases, in vitro human multicellular culture systems have been developed. These in vitro cell culture models have been extremely valuable in determining the toxic effects of novel compounds on cellular fun…