Search results for "drug interactions"
showing 10 items of 229 documents
Fluvastatin stabilizes the blood–brain barrier in vitro by nitric oxide-dependent dephosphorylation of myosin light chains
2006
Inhibition of the 3-hydroxy-3-methylglutaryl-coenzyme-A reductase and the downstream mevalonate pathway is in part responsible for the beneficial effects that statins exert on the cardiovascular system. In this study we aimed at analysing the stabilizing effects of fluvastatin on the blood-brain barrier (BBB) integrity, using an in vitro co-culture model of ECV304 and C6, or primary bovine endothelial cells and rat astrocytes. Fluvastatin dose-dependently (1-25 micromol/l) increased barrier integrity as analysed by measurements of transendothelial electrical resistance (TEER). This effect (117.4+/-2.6% at 25 micromol/l) was significantly reduced by the nitric oxide (NO) synthase inhibitor L…
Methylprednisolone neutralizes the beneficial effects of erythropoietin in experimental spinal cord injury
2005
Inflammation plays a major pathological role in spinal cord injury (SCI). Although antiinflammatory treatment using the glucocorticoid methyprednisolone sodium succinate (MPSS) improved outcomes in several multicenter clinical trials, additional clinical experience suggests that MPSS is only modestly beneficial in SCI and poses a risk for serious complications. Recent work has shown that erythropoietin (EPO) moderates CNS tissue injury, in part by reducing inflammation, limiting neuronal apoptosis, and restoring vascular autoregulation. We determined whether EPO and MPSS act synergistically in SCI. Using a rat model of contusive SCI, we compared the effects of EPO [500-5,000 units/kg of bod…
Effect of diazoxide on left ventricular performance in hypertension.
1975
The effect of diazoxide on left ventricular performance during rest and isometric exercise (handgrip) was examined in 16 unselected hypertensive patients, 6 of whom had been pretreated with the beta-adrenergic blocking agent pindolol. Diazoxide regularly and promptly produced a fall in left ventricular systolic and end diastolic pressures, and an increase in heart rate and left ventricular dp/dtmax. Haemodynamic changes were maximal 2 minutes after injection of the drug and decreased little over the next 8 minutes. After beta-adrenergic blockade, diazoxide caused a more pronounced reduction in left ventricular systolic pressure and a less marked fall in end-diastolic pressure, whilst the di…
The positive inotropic effect of phenylephrine in the presence of propranolol. Increase in time to peak force and in relaxation time without increase…
1978
The effects of phenylephrine on the shape of the contraction curve and on the cyclic adenosine 3',5'-monophosphate (c-AMP) content were studied in electrically driven (frequency 0.2 Hz) cat papillary muscles. All experiments were done in the presence of 1 micron propranolol in order to minimize interference from beta-adrenoceptors. 1. Phenylephrine increased the force of contraction in a concentration-dependent manner. Maximal effects (about 200% of control) occurred at 30 micron phenylephrine. 2. The positive inotropic effect (PIE) of phenylephrine was antagonized by phentolamine. Phentolamine, 5 micron, produced a parallel shift of the concentration-response curve for the PIE of phenyleph…
Electrical and mechanical activity of mammalian heart muscle fibres treated with papaverine
1977
The action of papaverine on electrical and mechanical activity was investigated in ventricular and atrial heart muscle fibres from guinea-pigs and cats. 1. Papaverine (10−5 M–5×10−5M) had positive, negative or no inotropic effects in ventricular preparations; positive inotropic effects were not observed after pretreatment of the animals with reserpine. In atrial preparations, papaverine (2×10−5M) had a positive inotropic effect that was independent of endogenously stored catecholamines. 2. The effects of isoprenaline and dibutyryl cyclic AMP were potentiated by papaverine (10−5 M–2×10−5M). 3. The action potential duration was always prolonged by papaverine in ventricular as well as in atria…
The addition of interleukin-2 to cyclophosphamide therapy can facilitate tumor growth of B16 melanoma.
1995
The role of interleukin-2 (IL-2) on tumor growth of B16F10 melanoma cells was assessed in two sets of mice with different immune status: normal (immunocompetent) mice and immunodeficient mice. The two sets of animals were treated with cyclophosphamide (CY) or IL-2 alone or with a combined therapy of CY+IL-2. On days 6 and 10 after tumor cell injection, we evaluated the incidence of hepatic B16 melanoma metastases and the percentage of hepatic volume occupied by metastatic tissue. We observed that the CY alone (300 mg/kg, days 3 and 8 post-tumoral inoculation) significantly reduced tumor growth in all treated mice; however, CY proved more effective in normal recipients than in immunodeficien…
Interactions of pharmaceutical companies with world countries, cancers and rare diseases from Wikipedia network analysis
2019
AbstractUsing the English Wikipedia network of more than 5 million articles we analyze interactions and interlinks between the 34 largest pharmaceutical companies, 195 world countries, 47 rare renal diseases and 37 types of cancer. The recently developed algorithm using a reduced Google matrix (REGOMAX) allows us to take account both of direct Markov transitions between these articles and also of indirect transitions generated by the pathways between them via the global Wikipedia network. This approach therefore provides a compact description of interactions between these articles that allows us to determine the friendship networks between them, as well as the PageRank sensitivity of countr…
Influence of calcium on the effects of okadaic acid and its interaction with caffeine and theophylline in rat myometrium.
1994
The effects of okadaic acid (OA), a monocarboxylic acid produced by marine dinoflagellates belonging to the genera Dinophysis and Prorocentrum, and their interactions with theophylline and caffeine were studied on the rat-isolated uterus in a calcium-containing medium and a calcium-free medium in the presence of 10−3 M EGTA. Okadaic acid (5 × 10−6 to 5 × 10−5 M) induced a concentration-dependent contraction of the rat-isolated uterus corresponding, with 5 × 10−5M, to 142.3±6.1% (n = 7) of the contraction induced by oxytocin 10−6 M. The time to peak tension was inversely proportional to the maximum effect produced. The contraction was not sustained and was followed by a concentration-depende…
Fortification of milk with calcium: effect on calcium bioavailability and interactions with iron and zinc.
2006
Calcium solubility, dialysability, and transport and uptake (retention + transport) by Caco-2 cells as indicators of calcium bioavailability have been estimated in the in vitro gastrointestinal digests of milk and calcium fortified milk. A significant linear correlation (p < 0.05) was obtained between calcium uptake and the amount of soluble calcium added to the cells, and also between percentage calcium uptake and the calcium measured in the analyzed samples. The solubility, dialysis, transport, and uptake values are higher (p < 0.05) for calcium fortified milks than for nonfortified milks; that is, calcium fortification increases not only calcium content but also its bioavailability. An i…
Beta-MSH inhibits brain inflammation via MC(3)/(4) receptors and impaired NF-kappaB signaling.
2005
The anti-inflammatory effects of melanocortin peptides have been demonstrated in different inflammation models. This is the first report describing the molecular mechanisms for the beta-MSH-induced suppression of bacterial lipopolisaccharide (LPS)-caused brain inflammation. We found that beta-MSH suppresses LPS-induced nuclear translocation of the transcription factor NF-kappaB, and inhibits the expression of inducible nitric oxide synthase, and the following nitric oxide overproduction in the brain, in vivo. Moreover, administering the preferentially MC(4) receptor selective antagonist HS014 blocked completely these effects, suggesting a tentative MC(4) receptor mediated mechanism of actio…