hematoencephalic barrier

This review summarizes the current knowledge about the general toxicity of thallium (Tl) and its environmental sources, with special emphasis placed on its potential mutagenic, genotoxic, and cytotoxic effects on both eukaryotic and prokaryotic cells. Tl is a nonessential heavy metal that poses environmental and occupational threats as well as therapeutic hazards because of its use in medicine. It is found in two oxidation states, thallous (Tl(+)) and thallic (Tl(3+)), both of which are considered highly toxic to human beings and domestic and wild organisms...

The review is dedicated to the role of sensory nerve endings of the gut, vegetal and central nervous system (CNS) in the diseases of gastrointestinal tract. Molecular-cellular inter-relations of nerve endings of the gut and neurons of the CNS are a key axis that among with neuroendocrine and immune responses, define the clinical manifestation and rehabilitation potential of the patient in the development of infectious process in the gut. Infectious-inflammation processes in the gut of various etiologies promote the increase of permeability of the intestine barrier with consequent trans-intestinal translocation of toxins and molecular mediators of inflammation to the system bloodstream...

Tryptophan (Trp) is present in the serum, partly bound to albumine and in the free form. The unbound portion of circulating tryptophan has the property of crossing the hematoencephalic barrier and being converted within the brain into serotonin (5-HT) through the enzymatic processes of hydroxylation and decarboxylation. The serotoninergic system plays an important role in neuroendocrine control of reproductive hormone secretion, and in particular, it may influence GnRH pulsatility, a function essential for reproductive processes...

The cerebral metastases are frequent in the evolution of breast cancer and convey a poor prognosis. The frequency depends on the histology of the cancer and on the expression of oestrogen and progesterone receptors as well as of HER2 antigen. The treatment is currently based on surgery and the different modalities of radiotherapy used alone or in association. Indeed, chemotherapy agents available for the treatment of breast cancer do not cross the hematoencephalic barrier and are thus ineffective. However, some encouraging results have been recently reported with the therapies targeting HER2...

The present paper deals with a complex spectral and physicochemical evaluation of mono[{3-[4-(2-etoxyetoxy)-benzoyloxy]-2-hydroxypropyl}-isopropylammonium]fumarate, a potential ultrashort acting beta1-blocker. The identity of the substance under study (labelled as UPB-1) was confirmed by 1H- and 13C-NMR spectra as well as IR spectrometry. The determined fundamental physicochemical characteristics included the determination of the melting point, solubility in a spectrum of solvents, verification of purity (adsorption thin-layer chromatography), determination of surface activity (Traube's stalagmometric method), acidobasic characteristics (pK(a) value by means of alkalimetric titration), determination of log epsilon values using spectrophotometry in UV/VIS region, as well as the evaluation of the effect of acid and basic media on the stability of the substance under the study...

The aim of the work was to study effect of peripheral administration of mu-opioid receptor ligands unable to penetrate through the hematoencephalic barrier on the measures of emotionality in rats and on the release of beta-endorphins from nerve endings of the anterior cingulate cortex during emotional stress. The mu-opioid receptor agonist loperimide mostly acted as an anxiolytic whereas the receptor antagonist methylnaloxon showed depressive activity. Lifetime microdialysis and subsequent immunoenzyme assay demonstrated that intraventricular infusion of loperamide and methylnaloxon decreased and increased respectively the surge of beta-endorphin into the intercellular space...

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Perifocal ischemia zone ultrastructural changes caused by unilateral photoinduced thrombosis of the rat prefrontal brain and reciprocal changes in an opposite hemisphere of a brain in 1 and 24 hours after an ischemia are investigated. Reactive changes of microcirculation, astrocytes, neurons in the perifocal zone of the ischemia, and also in the contralateral site of the intact hemisphere as increase in hematoencephalic barrier permeability, numbers of degraded neurons, astrocyte transport injury and glucose metabolic imbalance are revealed...

AIMS: Zinc is an ion that participates in basic cellular and tissular functions. Zinc deficiency is present in many physiological and health problems affecting most body organs, including the brain. Among the circumstances involved in zinc deficiency, ethanol consumption is probably one of the most frequent. A dietary zinc supplement has been proposed as possibly being an efficient method to palliate zinc deficiency. Astrocytes form part of the hematoencephalic barrier, and they are apparently implicated in the homeostasis of the neuronal medium...

The purpose of our research was the study of diagnostic possibility of neurospecific enolase (NSE) as a marker of hematoencephalic barrier (HEB) dysfunction in newborn infants of different gestational age with perinatal injury of central nervous system (CNS). It was determined that the concentration of NSE in blood serum by the immunoenzyme method in 98 newborns of different gestation age with hypoxic-ischemic injury of CNS in dynamics of neonatal period (0-1, 5-7, 12-14, 20-21, 28-30 days). It was found that the concentration of NSE was changed depending on the character of CNS injury (intraventricular hemorrhage, periventricular leucomalacia)...

Hypertension can result from neuronal network imbalance in areas of central nervous system that control blood pressure, such as the nucleus tractus solitarius (NTS). There are several neurotransmitters and neuromodulatory substances within the NTS, such as adenosine, which acts on purinoreceptors A(2a) (A(2a)R). The A(2a)R modulates neurotransmission in the NTS where its activation may induce decrease in blood pressure by different mechanisms. Nicotine is a molecule that crosses the hematoencephalic barrier and acts in several areas of central nervous system including the NTS, where it may interact with some neurotransmitter systems and contributes to the development of hypertension in subjects with genetic predisposition to this disease...

A mechanistic model of the cardiovascular system is supposed to provide three variants of an elevation of hydraulic pressure: 1) a reduction in arterial bed volume with unchanged intravascular fluid volume; 2) an increase in intravascular fluid volume without unchanged vascular bed volume; 3) an elevation of blood flow resistance in the system with unchanged volumes of both the system itself and circulating fluid. The first variant includes arterial hypertension (AH) in pheochromocytoma, glucocorticoid hyperproduction, and psychoemotional stress...

Comprehensive analysis of criteria for the severity of clinical conditions in patients with craniocerebral injuries included characteristics of cerebrospinal fluid and lesions of hematoencephalic barrier (HEB). The study revealed the relationship between clinico-neurological conditions of the patients, liquor nitrite levels, and HEB permeability. An attempt was undertaken to evaluate efficiency of liquor-corrective treatment in combination with intense therapy in patients with severe cerebral injuries.

Hyperhidrosis may be an adverse drug event (ADE) induced by the effect on any of the components of human thermoregulation. Some of our efavirenz (EFV)-treated patients have reported excessive nocturnal sweating that resolved after dose reduction. A representative clinical case of a male patient being treated with a night-time 600-mg dose of EFV who reported severe nocturnal sweating is reported here. His EFV plasma concentrations were always above normal and he was homozygous for a deficient function-allele of CYP2D6; for this reason, his EFV dose was reduced to 400mg=d...

Captopril and mesna are molecules with a free thiol group, used as active ingredients due to their hypotensor and mucolytic properties, respectively. These compounds cross the hematoencephalic barrier and, due to the reactivity of their thiol group, can form adducts with the o-quinones formed during the oxidation of mono- and o-diphenols. Polyphenol oxidase from plants and fungi can be used as a tool for generating o-quinones in their action on o-diphenols and facilitate the formation of adducts in the presence of captopril or mesna...

Tacrolimus is an agent used in clinical immunosuppressive drug therapies. A wide spectrum of adverse effects has been reported in association with this immunosuppressor, including neurotoxic effect. The upper limit of therapeutic blood concentrations of tacrolimus has been described as 30 ng/ml in immunosuppressed patients. We investigated the effect of this therapeutic dose of tacrolimus on the expression and activity of the multidrug resistance protein 1 (MDR1 or Pgp, P-glycoprotein) and ATP-binding cassette transporters A5 (ABCA5) in human brain microvascular endothelial cells (HBMEC), derived from Blood-Brain Barrier (BBB) endothelium, these being the most predominantly expressed transcripts in these cells...

OBJECTIVE: Tryptophan, the serotonin (5-HT) precursor, is circulating in blood in both free (FT) and protein-bound forms. The free form crosses the hematoencephalic barrier and is converted into 5-HT. During the fertile years, tryptophan levels are negatively correlated to gonadotropin concentrations. The present study aims to evaluate the correlation between circulating tryptophan, gonadotropin and estradiol (E2) levels postmenopause. METHODS: Serum levels of total tryptophan (TT, free + protein-bound) and FT, and plasma luteinizing hormone (LH), follicle stimulating hormone (FSH), and E2 were determined in 15 postmenopausal women and 15 cycling women during follicular (days 7-10), periovulatory (days 13-16) and luteal (days 21-24) phases of the menstrual cycle...

The solution to the problem of transportation of high-molecular substances via the hematoencephalic barrier (HEB) is a necessary condition for the development of theoretical and applied aspects of selective transport of biologically active substances (neurotrops, medications) from blood into the brain. In the last decades, views on the possibility of macromolecular transport through intact HEB have changed substantially. Under physiological conditions, translocation of macromolecular substances via HEB is performed with the help of specific molecular transport systems and by endocytosis...

The article covers the results of research into the levels of S100b protein and antibodies to it in the serum of patients with crisis and stable essential hypertension. The results show that neutrophic protein dysmetabolism plays an important role in the pathogenesis of hypertonic dyscirculatory encephalopathy and the forming of cognitive disorder syndrome. The data obtained suggest that hypertensive crises lead to pathologic changes in hematoencephalic barrier permeability and the development of autoimmune reactions with participation of neutrophic proteins...

Multiple therapeutic modalities have been used to treat hepatic encephalopathy. L: -Acetylcarnitine (LAC) is a physiologically active substance that improves both the energetic and the neurotransmission profiles. LAC is able to cross the hematoencephalic barrier and reach the cerebral regions, where the acetylic group may be utilized. The aim of this work was to evaluate the efficacy of LAC in the treatment of hepatic coma in cirrhotic patients. Twenty-four suitably selected patients were enrolled in the study and, following randomization, received either LAC (n=13) or placebo (n=11)...