The Role of Flavonoids as a Cardioprotective Strategy against Doxorubicin-Induced Cardiotoxicity: A Review

Doxorubicin is a widely used and promising anticancer drug; however, a severe dose-dependent cardiotoxicity hampers its therapeutic value. Doxorubicin may cause acute and chronic issues, depending on the duration of toxicity. In clinical practice, the accumulative toxic dose is up to 400 mg/m² and increasing the dose will increase the probability of cardiac toxicity. Several molecular mechanisms underlying the pathogenesis of doxorubicin cardiotoxicity have been proposed, including oxidative stress, topoisomerase beta II inhibition, mitochondrial dysfunction, Ca²⁺ homeostasis dysregulation, intracellular iron accumulation, ensuing cell death (apoptosis and necrosis), autophagy, and myofibrillar disarray and loss. Natural products including flavonoids have been widely studied both in cell, animal, and human models which proves that flavonoids alleviate cardiac toxicity caused by doxorubicin. This review comprehensively summarizes cardioprotective activity flavonoids including quercetin, luteolin, rutin, apigenin, naringenin, and hesperidin against doxorubicin, both in in vitro and in vivo models.     

Study on bioequivalence of beraprost in healthy volunteers by liquid chromatography with tandem mass spectrometry

Beraprost sodium is an oral prostacyclin analog that was first approved in 1992 (Japan) for the treatment of peripheral vascular disorders. It is administered orally as a tablet available in strength 20 μg. In this paper, we described a liquid chromatography tandem mass spectrometry method that was developed for the quantification of beraprost in human plasma with high sensitivity at picogram per milliliter concentration. The method had been validated in terms of selectivity, sensitivity, accuracy and precision, matrix effect, linearity, recovery and carry‐over according to the Guideline on Bioanalytical Validation from the European Medicines Agency. The standard calibration curve for beraprost was 9.5–1419 pg/mL. This method has been applied successfully to a bioequivalence study with 60 μg of beraprost (three tablets) in 29 healthy volunteers. The results showed that the two formulations of beraprost are bioequivalent.     

Measurements of steady-state heat dissipation from miniaturized horizontally-based straight rectangular fin arrays

Experiments have been conducted to investigate the effects of miniaturizing the base plate dimensions of horizontally-based straight rectangular fin arrays on the steady state heat dissipation performance. The variation of the steady-state heat dissipation rates per unit base area and the average heat dissipation coefficients within a limited fin base excess temperature above the ambient temperature (from 20 to 50 °C) have been studied as integral aluminum alloy fin arrays were miniaturized by changing the ratio of the base width to length from 0.51 to 1.96 for two inter-fin spacing distances of 3 mm and 11 mm. The miniaturization process have been initiated from a square-based array of 49 × 49 mm (maximum base area of 24.51 × 10^–4m²) and terminated at a square-based array of 25 × 25 mm (minimum base area of 6.25 × 10^–4m²) with rectangular-based arrays of varying intermediate areas in between. Relevant non-dimensional parameters formulated by earlier similarity analyses for large fin arrays with comparable inter-fin-spacing distances and fin heights have been found inadequate for generalizing the results. Modifications to correlations proposed for large fin arrays have been made by including the effect of varying the value of the base width to length ratio parameter to correlate the data for miniaturized fin arrays. Two types of correlations for miniaturized horizontally-based straight rectangular fin arrays, one which used the inter-fin separation distance as the prime geometric parameter, and the other, which employed half the fin length, have been presented, on the basis of the experimental conditions of this investigation.An erratum to this article can be found at     

Concurrent calorimetric and interferometric studies of steady-state natural convection from miniaturized horizontal single plate-fin systems and plate-fin arrays

Concurrent calorimetric and interferometric studies have been conducted to investigate the effect that reduction of the base-plate dimensions has on the steady-state performance of the rate of natural convection heat transfer from miniaturized horizontal single plate-fin systems and plate-fin arrays. The effect was studied through comparison of the present results with those of earlier relevant calorimetric, interferometric, or numerical studies. Results shown that a reduction of the base-plate area by 74% increased natural convection coefficient by 1.5 times to 26.0 W m^?2 K^?1 for single fin systems and by 1.8 times to 18 W m^?2 K^?1 for fin arrays in the range of the base-plate temperature excess of 20–50°C. A simple correlation for the Nusselt number of miniaturized horizontal plate-fin arrays is proposed in the range of Rayleigh number divided by the number of fins to the 2.7 power from 2 × 10 to 5 × 10⁵.     

Measurements of heat dissipation from miniaturized vertical rectangular fin arrays under dominant natural convection conditions

Experiments have been conducted to investigate the effects of miniaturizing the base plate dimensions of vertically based straight rectangular fin arrays on the steady-state heat-dissipation performance under dominant natural convection conditions. The miniaturization process was initiated from a square-based array of 49×49 mm² (maximum base area) and terminated at a square-based array of 25×25 mm² (minimum base area) with rectangular-based arrays of varying intermediate areas in between. Two inter-fin separation distances of 3 and 11 mm were used. The effect of base plate orientation on the heat-dissipation performance was studied through comparison of present results with those of an earlier work, in which the arrays were miniaturized with the base horizontally oriented. A correlation for miniaturized vertically based straight rectangular fin arrays, which employed the fin length as the prime geometric parameter, has been presented on the basis of the experimental conditions of this investigation.