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Results for “HEMATO-ENCEPHALIC BARRIER”

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At least 19 recordsLinked to original sources
PubMed1977

[Effect of euphylline and caffeine on the permeability of the hemato-encephalic barrier for benzylpenicillin in experimental and clinical meningococcal meningitis].

Higher benzylpenicillin levels in the cerebrospinal fluid and soft brain membranes were determined in experiments on a model of meningococcal meningitis of rabbits and in clinics in patients with meningococcal meningits subjected to combined treatment with massive doses of the antibiotic and the therapeutic doses of euphylline or caffeine. Benzylpenicillin excretion with urine and the antibiotic blood levels did not significantly change under the action of the diuretics. The phenomenon must be due to the vasolidative effect of the drugs of the purine group, improved blood supply of the soft brain membranes and increased permeability of the hemato-encephalic barrier for benzylpenicillin.

Aminophylline↗
PubMedDate not supplied

[Effect of promedol and fentanyl on the permeability of the hemato-encephalic barrier of rats for noradrenaline-H3].

In tests situations with rats it was shown that promedol and phentanide produce an analgetic action accompanied by a reduced flow of tagged norepinephrine from the blood into the brain. A parallelism between the dosage of the substances and the intensity of the analgetic effect and the degree of changed permeability of the blood-cerebral barrier could be noted.

Animals↗
PubMed1992

[The ultrastructural changes in the hemato-encephalic barrier in the neocortex of rat progeny with prenatal exposures to desoxycorticosterone acetate].

Electron microscopic methods were used to study the antero-parietal area of the cortex of newborn rats from intact mothers (I group) and rats born after intramuscular injection of desoxycorticosterone acetate (DOCA) to pregnant rats during the III trimester (II group) in dose 10 mkg/100 g of the body mass or during the II-III trimester of gestation (III group) in dose of 2 mkg/100 g. By the moment of delivery the hormone dose in the both experimental groups was gradually decreased up to 0.8 mkg/100 g of the body mass. Prenatal treatment by DOCA resulted in the following changes in the structure of hematoencephalic barrier: ultrastructural changes of endotheliocytes and pericytes showing accelerated synthetic and metabolic processes; lengthening of interendotheliocytic dense junctions, increase of the amount of astroblast peduncles; accelerated development of the basement membrane (lengthening and thickening) and differentiation of astroblasts. Signs of accelerated differentiation of glioblasts and vascular wall were much more pronounced in the neocortex of the III group of animals. However, part of the vessels were surrounded by edema. The perivascular edema was accompanied by loosening of the basement membrane, flattening of endotheliocytes, pericytes and increase of their electron density.

Animals↗
PubMed1992

[A structural analysis of hemato-encephalic barrier function in bacterial meningoencephalitis].

A correlation analysis of the content of metals in the cerebrospinal fluid in 70 patients with bacterial meningoencephalitis showed that an increase of permeability of microvessel walls for macro- and microelements is accompanied by a reduction of the regulating activity of barrier structures. Pathomorphological examination of the brain by the method of scanning electron microscopy revealed structural changes of the microvessel walls as the basis of disorders of the barrier-transport function.

Bacterial Infections↗
PubMed1991

[An immunochemical analysis of the function of the hemato-encephalic barrier in acute fetal hypoxia and asphyxia neonatorum].

The neurospecific protein alpha 1-globulin has been assayed in serum in order to evaluate the blood-brain barrier in newborns with acute intrapartum hypoxia. The study involved 35 term newborns with birth asphyxia of variable severity. The alpha 1-globulin levels correlated with severity of condition at birth, duration of intrauterine exposure to hypoxia and the presence of obstetric complications and clinical severity of cerebral circulatory disorders. A normal early adaptation and effective therapy reduced serum alpha 1-globulin levels 4-8-fold on the 3rd postnatal day and 6-16-fold on the 5th day. Deterioration of neurological symptoms was parallelled by a significant increase in protein levels (to 6400 ng/ml) at day 5. This evidence may confirm the fact that permeability of the blood-brain barrier is impaired by intrapartum hypoxia.

Acute Disease↗
PubMed1991

[The use of a method of mathematical analysis in studying the permeability of the hemato-encephalic barrier in bacterial meningoencephalitis].

The authors studied the blood-brain barrier permeability in 70 patients depending on the severity and terms of bacterial meningoencephalitis. It was shown that employment of the probability-statistical analysis of quantitative content of metal in the blood and cerebrospinal fluid allows to evaluate the working regimen of the blood-brain barrier from initial manifestations of functional insufficiency to failure of barrier compensation systems.

Acute Disease↗
PubMed1991

[The regulatory function of the hemato-encephalic barrier in bacterial meningoencephalitis].

The author studied the permeation of the blood brain barrier to metals in 70 patients depending on the severity and terms of meningoencephalitis. It is shown that use of the probability-statistical analysis of the quantitative content of metals in in the blood and cerebrospinal fluid allows to fix the regimen of the blood brain barrier work from initial manifestations of functional insufficiency up to disorders of regulatory mechanisms and their metabolism.

Bacterial Infections↗
PubMedDate not supplied

[Blood plasma proteins and drug transport across the hemato-encephalic barrier].

The blood-brain barrier being a dynamic membrane interface between the blood and the brain is of great importance for the formation of the pharmacokinetics and pharmacodynamics of neurotropic drugs. One of the main factors influencing diffusion of drugs into the central nervous system is the degree of their binding by plasma proteins. It was supposed that only the unbound fraction of drugs is pharmacologically active. However in some papers the plasma-protein-mediated transport into the rat brain of endogenous compounds and drugs was demonstrated. This indicates that the measuring of the free fraction of a drug in vitro can lead to the underestimation of its concentration in the target organ.

Animals↗
PubMed1976

[Antibiotic penetration through the blood-brain barrier in rats and the effect on this process of proteolytic enzymes].

Penetration of penicillin, ampicillin, oxacillin, tetracycline, streptomycin and gentamycin through the hemato-encephalic barrier in rats and effect of proteolytic enzymes on the above process were studied comparatively. The levels of penetration to the brain were highest for ampicillin, then followed penicillin, tetracycline, oxacillin, streptomycin and gentamycin. Preliminary intramuscular administration of trypsin and chimotrypsin (10 mg/kg) to the animals had no effect on permeability of the hemato-encephalic barrier for the antibiotics tested, except penicillin. Higher levels of the antibiotics in the brain tissue may be explained by higher antibiotic blood levels under the effect of proteolytic enzymes.

Ampicillin↗
PubMed1977

[Effect of furosemide on the pharmacokinetics of benzylpenicillin and its penetration through the hematoencephalic barrier in experimental and clinical meningococcic meningitis].

Pharmacokinetics of sodium benzylpenicillin after intramuscular administration in a dose of 250 000 gamma/kg and simultaneous intramuscular injection of furosemid (lazix) in doses of 0.5--1--2 mg/kg was studied in experiments on a model of meningococcal meningitis of rabbits and in clinics on patients with meningococcal meningitis. A pronounced effect of furosemid on pharmacokinetics of benzylpenicillin as dependent on a number of factors was found. Furosemid and meningococcal endotoxin had a synergic effect and decreased benzylpenicillin excretion with urine resulting in prolongation of the antibiotic effect in the blood. An increase in benzylpenicillin blood levels and inflammation of the soft brain membranes increased permeability of the hemato-encephalic barrier for the antibiotic.

Animals↗
PubMed1976

[Antibiotic interaction with proteolytic enzymes].

The effect of penicillin, tetracycline, aminoglucozide antibiotics and streptomycin on BAEE-esterase activity of trypsin was studied. It was found that benzylpenicillin in amounts of 50, 100 and 300 mg, ampicillin in an amount of 25 mg, methicillin in an amount of 12 mg and tetracycline in an amount of 2.5 mg as calculated per 1 mg of trypsin had no effect in vitro on the esterase activity of the enzyme. Neomycin, kanamycin and streptomycin in amounts of 5, 10, 100 or 300 mg per 1 mg of trypsin catalyzed splitting of BAEE by trypsin. When the antibiotics were added to the bile, its esterase activity increased. Preliminary intramuscular administration of trypsin and kanamycin to the rats had no effect on the ampicillin levels in the blood serum and brain and did not affect the permeability of the hemato-encephalic barrier as compared to the use of trypsin alone.

Aminoglycosides↗
PubMedDate not supplied

[Antivitamin activity of oxythiamine disulfide nicotinate].

The B1-antivitamin activity of oxythiamine disulphide nicotinate has been determined in experiments on albino mice and it is shown that in the liver this derivative exerts the equal action while in the blood and heart--a more profound and prolonged inhibitory action on the transketolase activity in comparison with oxythiamine disulphide. Like the initial compound oxythiamine disulphide nicotinate does not penetrate through hemato-encephalic barrier and does not inhibit the brain transketolase.

Animals↗
PubMed1991

[Subacute organic psychosyndrome as a clinical manifestation of infection with stage II Borrelia burgdorferi without further neurologic manifestations].

A 60-year old man developed a subacute psychoorganic syndrome over four weeks. CCT was normal, except a slight atrophy of the cerebellar superior vermiform process. In the CSF we found 1696/3 cells, suggesting a lesion of the hemato-encephalic barrier, an autochthonous IgG production and an increased specific antibody-titre (10.3) for Borrelia burgdorferi. Based on these data a Lyme-Neuroborreliosis being diagnosed. Treatment with Cefotaxim and Gentamycin was successful, a complete remission of the psychopathological symptoms had been obtained. This case is an uncommon manifestation of a Borrelia-burgdorferi-infection of the CNS with psychopathological symptoms but no neurological deficit. We conclude that an affection of the CNS with Borrelia burgdorferi must always be taken into consideration in patients presenting a subacute psychoorganic syndrome of unknown etiology.

Borrelia burgdorferi Group↗
PubMed1977

[Ultrastructure and function of cellular elements of the thymus during formation of antitubercular immunity].

Electron microscope and histochemical study of the thymus was carried out on growing guinea pigs under normal conditions and during the immune responses in BCG vaccination. During the postvaccinal period, particularly at periods of from 3 to 7 days, there was a change in the cell elements ultrastructure of the hemato-encephalic barrier. The greatest shifts were noted in the reticular and endothelial cells. The data obtained pointed to the intensification of the morpho-functional activity of the mentioned cell elements of the thymus during the formation of antituberculosis immunity.

Acid Phosphatase↗
PubMed1976

[Clinical pharmacokinetics of 2-C14-ftorafur in patients with astrocytoma].

Patients with dedifferentiated brain astrocytoma during an operation were injected intravenously 2-C14-fluorofur (3 muC/Kg). In different periods after the injection the level of radioactivity was determined in different sites of the tumor, brain tissue, as well as in blood plasma, cerebrospinal liquor and urine. Intracellular localization of the labeled substance in the tumor tissue was examined autohistoradiographically. 2-C14-fluorofur was found to readily penetrate the hemato-encephalic barrier and to be absorbed both by tissues of neuroectodermal tumor and adjacent brain tissues. In astrocytoma cells the labelled substance is localized mainly extranuclearly. Radioactive products are excreted from the organism slowly and their traces are observed in blood, cerebrospinal liquor and urine even on the third day postoperatively.

Astrocytoma↗