Yet Another Doctor Blog On The Internet

Bartonellosis causing bilateral Leber neuroretinitis: a case report.


Drug toxicity may occur due to dangerous drug combination. We aimed to investigate the influence of verapamil (a P-gp inhibitor)--bufadienolides interaction on cardiotoxicity and bufadienolide uptake by the isolated heart. The study was performed in Langendorff isolated perfused guinea-pig hearts by bufadienolides infusion in the absence and presence of verapamil (250, 500ng/ml). Arrhythmia parameters were evaluated by ECG and the content of bufadienolides in heart were measured by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS). In the present of verapamil, the wide QRS duration and lightly rapid heart rate (HR) were markedly reduced in the early stage of bufadienolide intoxication. However, the ECG changes characterized by prolonged P-R interval, and slow heart rate and low QRS amplitude in the late stage of bufadienolide intoxication were significantly enhanced. Furthermore, the contents of a variety of bufadienolide compounds in the verapamil+bufadienolide group were significantly higher when cardiac arrest occurred. Although verapamil reduced the bufadienolide-induced ventricular arrhythmias, verapamil worsened heart block and lethal bradycardia of bufadienolides partly via increasing the uptake of bufadienolides in heart tissue, which could compromise the protective effects of verapamil against bufadienolide intoxication. These results suggested that the verapamil may produce dangerous interactions with drugs containing bufadienolides.

Taken together, these data suggest these cells will be useful for evaluation of rat Abcb1a-mediated transport and for evaluation of species-specific P-glycoprotein-mediated transport.

An overall of 61 patients was evaluated. Left ventricular mass had decreased by 13.5% during the 6-month treatment period. This reduction neither correlated with the baseline left ventricular mass nor with the extent of blood pressure decrease.

This study was performed to examine the effects of the calcium channel blockers, nifedipine, amlodipine, diltiazem, and verapamil on the activation of the transcription factor NF-kappaB. A549 cells, a human epithelium-like lung carcinoma cell line, were transfected with the NF-kappaB reporter plasmid, which contains the luciferase gene driven by promoters containing a TATA element and 5 copies of the kappaB cis-acting element, and co-transfected with 0.2 microg of pSV2neo vector using LipofectAMINE. Nifedipine significantly decreased the expression of luciferase protein stimulated with IL-1beta (1 ng/mL) compared with controls: 80+/-4% at 3 micromol/L, 47+/-2% at 10 micromol/L and 30+/-2% at 30 micromol/L (each, n=3, p<0.0001). The inhibitory effect of nifedipine on promoter activity was concentration-dependent, with a maximal effect obtained at 30 micromol/L. In contrast, high concentrations (30 micromol/L) of amlodipine, diltiazem or verapamil decreased promoter activity to only 89+/-3%, 90+/-3% or 87+/-2% of control, respectively. A comparable inhibitory effect of nifedipine was observed when cells were stimulated with tumor necrosis factor (TNF)-alpha (50 ng/mL), or phorbol 12-myristate 13-acetate (PMA, 100 ng/mL). Electrophoretic mobility shift assay by lipopolysaccharide stimulation, using the RAW 264.7 macrophage cell line, also showed inhibition of NF-kappaB activation by nifedipine in concentrations of 30 and 50 micromol/L. Nifedipine possesses the unique property of inhibiting NF-kappaB, which may be independent of its calcium channel blocking activity, and may, in part, explain its immunosuppressive effect.

One of the key factors in drug discovery is related to the metabolic properties of the lead compound, which may influence the bioavailability of the drug, its therapeutic window, and unwanted side-effects of its metabolites. Therefore, it is of critical importance to enable the fast translation of the experimentally determined metabolic information into design knowledge. The elucidation of the metabolite structure is the most structurally rich and informative end-point in the available range of metabolic assays. A methodology is presented to partially automate the analysis of this experimental information, making the process more efficient. The computer assisted method helps in the chromatographic peak selection and the metabolite structure assignment, enabling automatic data comparison for qualitative applications (kinetic analysis, cross species comparison).

RPE cells from human donor eyes were enzymatically dissociated and cultured on collagen gels. Transdifferentiated RPE cells (seventh and eighth passage) were used for experiments. The contraction assays were treated with different concentrations (10-1000 microM) of R-(+)-verapamil, S-(-)-verapamil, and racemic verapamil.

Prolonged exposure to glibenclamide activates protein translation in pancreatic beta cells through the calcium-regulated mTOR, PKA and MEK signalling pathways. The observed intercellular differences in translation activation are proposed as underlying mechanism for functional heterogeneity in the pancreatic beta cell population.