Dynamic behavior modeling of cigarette smoke particles inside the car cabin with different ventilation scenarios

Dynamic behavior of cigarette smoke particles inside the cabin of cars is investigated and the respirable suspended particles concentration during and after smoking cigarette is predicted in this study. The model is based on mass balance equations. The mechanisms of deposition on the surfaces and the exchange of air in the cabin are considered as sinks for emitted particles. The coagulation is accounted as a sink for smaller particles and as a source for larger particles. The various scenarios of smoking in the cars available in the literature are simulated in this study. Good agreement between the results of the present model and the experimental data, as well as the predictions of other available models, is reached. The mean respirable suspended particles concentration in different scenarios is estimated and compared with Environmental Protection Agency health-based standards in order to specify the situations with respirable suspended particles concentrations exceeding the allowable limits. The results show that the concentration of particles due to the smoke of a single cigarette in a stationary medium-sized car with the air conditioner off is 33.6 microg/m3 and nearly reaches the limits appointed by the Environmental Protection Agency for a 24-h incremental exposure [35 microg/m3]. Corresponding values for moving cars have also been calculated and compared with the standards

role of K-ATP channel in the preconditioning effect of magnesium in the rat isolated heart

There is growing interest for beneficial effect of Mg in the cardiovascular disorders. A number of cardiovascular disorders including myocardial infarction, arrhythmias and congestive heart failure have been associated with low extracellular or intracellular concentrations of Mg. The aim of present study was to investigate the preconditioning effects of magnesium [Mg] on cardiac function and infarct size in the globally ischemic-reperfusion in isolated rat heart. Rat hearts were Langendorff-perfused, subjected to 30 minutes of global ischemia and 90 minutes of reperfusion, and assigned to one of the following treatment groups with 7 hearts in each group: [1] control, [2] ischemic- reperfusion, [IR], [3] ischemic preconditioning, [IPC] of 5 minutes of global ischemia - reperfusion before lethal ischemia; or pretreatment with [4] 30 Mu mol/L of Diazoxide [Dia], [5] 8 mmol/L magnesium, [6] 10 Mu mol/L glibenclamid [Gli], [7] magnesium and Dia and [8] magnesium and Gli. Infarct size was measured by the triphenyltetrazolium chloride method. Left ventricular function was assessed by left ventricular developed pressure [LVDP], heart rate and coronary flow [CF]. Mg limited infarct size [9.76% vs 44.47% in IR, P< 0.001] as did Dia [10.2% vs 44.4% in IR P< 0.001] and IPC [8.69% vs 44.47% in IR, P< 0.001]. The protective effect of magnesium was abolished by Gli. Administration of Mg had an anti-infarct effect in ischemic-reperfusion isolated rat hearts and improved cardiac function. Blockade of K-ATP channel abolished the protective effects of magnesium and suggest that K-ATP channel has an important role in this effects

Determination of isosteviol by LC-MS/MS and its application forevaluation of pharmacokinetics of isosteviol in rat

Isosteviol has been found to have potential preventive or therapeutic effects against hypertension, ischemia reperfusion injury, diabetes and cancer, but little is known about the pharmacokinetics [PK] of the compound. The aim of this study was to develop a liquid chromatographic-tandem mass spectrometric [LC-MS/MS] method for determination of isosteviol in rat plasma and to assess in a preliminary manner the PK of isosteviol after intravenous bolus injection. Ions of analytes were generated using electro-spray ionization and detected in the positive-ion mode in LC-MS/MS. Multiple reaction monitoring was performed, using the precursor product ion combination for isosteviol m/z 319.4 - 273.4. Progesterone was used as an internal standard. Nitrogen was used as the nebulising gas and unit resolution was set for Q1 and Q3. Isosteviol solution was injected through the penile vein of rats at a dose of 8 mg/kg. Blood samples were collected from a jugular vein cannula. The PK parameters were calculated using a two - compartment PK model. The LC-MS/MS assay for isosteviol in rat plasma was linear over the range of 0.5-80 micro g/ml. The terminal half life of isosteviol [t [1/2]] was 406 +/- 31.7 min and clearance [CL] was 2.9 +/- 0.3 ml/min/kg. A sensitive LC-MS/MS assay for isosteviol in plasma has been successfully established and used in a preliminary PK evaluation of isosteviol in rats