Myocardial toxicity of acute promyelocytic leukaemia drug-arsenic trioxide

BACKGROUND

Arsenic trioxide (As2O3) is an environmental toxicant as well as an effective anti cancer agent against many types of cancers. It is a promising drug for patients with relapsed acute promyelocytic leukaemia (APL), but its clinical efficacy is burdened by the serious cardiac toxicities.

AIM

The present study was designed to investigate the toxic mechanism of arsenic in cardiac tissue at its clinically relevant concentrations.

MATERIALS AND METHODS

Experimental rats were administered with As2O3 2, 4 and 8 mg/kg body weight, orally for a period of 45 days. Cardiac toxicities were recorded by lipid peroxidation, activities of glutathione dependent antioxidant and antiperoxidative enzymes, cardiac arsenic accumulation and histopathological changes.

RESULTS

In vivo studies revealed a significant rise in lipid peroxidation, decline in reduced glutathione, glutathione dependent antioxidant enzymes and antiperoxidative enzymes in the cardiac tissue of arsenic treated rats. The extent of free radical production was found increased with periodic rise in the arsenic concentration. The experimental group which received 8 mg/kg body weight of arsenic exhibited the highest deposition of arsenic in cardiac tissue. Light microscopic examination of cardiac tissues in arsenic treated rats has showed increased structural abnormalities like myocardial fibre swelling, capillary congestion and micro-haemorrhages.

CONCLUSIONS

The study concludes that the mechanism of arsenic induced cardiac toxicity is associated with the accumulation of arsenic in tissue and the extent of free radical production.

Pulmonary functions in workers of fertiliser and chemical industry

The present study was undertaken to assess the pulmonary functions in fertiliser and chemical industry workers of Kerala. Pulmonary function test was performed with Vitalograph Compact-II spirometer. Exposure to different chemicals, noxious gases and particulate matter of fertiliser and chemical industry was injurious to the normal pulmonary function. Significant decline in lung volumes, viz. FVC, FEV1, FEV1/FVC% (P < 0.01) and flow rates, viz. FEF25-75%, FEF0.2-1.2, FEF25%, FEF50%, FEF75% (P < 0.01) among non-smokers and smokers than that of normal controls was observed. The findings of this study also suggest that with increased duration of exposure to industrial pollutants, lung volumes and flow rates were significantly reduced in workers.

Spirometric impairments in undernourished children

The present study elucidates the effect of undernutrition on pulmonary functions in children. The study was carried out in healthy normals, wasted, wasted and stunted children. Spirometry was performed with Vitalograph Compact-II spirometer. Wasted, wasted and stunted children showed lower lung volumes, forced mid expiratory flow time and inspiratory flow rates than healthy normals. Wasted and stunted children had lower VC, FVC and FIF50% than wasted children. The reduction in lung volumes and flow rates in wasted children may be due to ventilatory muscle wasting. But in wasted and stunted children along with muscular wasting diminished skeletal growth is also a reason for lower lung functions. No airflow limitation was observed in undernourished children.

Prediction equation for lung functions in South Indian children

Lung functions including VC, IVC, FVC, FEV0.5, FEV1, PEF, FEF0.2-1.2, FEF25-75%, FEF75-85%, PIF, FMFT, MVV(IND), peak expiratory flow at 25%, 50% and 75% of FVC, peak inspiratory flow at 75%, 50%, 25% and the ratio between different lung volumes were measured with Vitallograph Compact-II spirometer on 109 South Indian school boys in the age group of five to sixteen years. The results show an increase in "lung volumes" and "flow rates" with increase in age, height and weight. FMFT and MVV(IND) also increase with increase in anthropometric measurements. All the lung functions except FEF75-85% and the ratio between different lung volumes show significant positive correlation with age, height and weight. Regression equations were derived for predicting normal lung functions for healthy South Indian boys. Lung volumes and flow rates were lower than North Indian and foreign boys. The decrease in lung functions in South Indian boys were due to their sea level dwelling, dietary habits and comparatively lower anthropometric measurements.

Pulmonary function studies in rowers

The present study attempts to investigate the pulmonary functions of snake boat rowers before and after rowing. This is made on 12 healthy traditional snake boat rowers ranging from age 16-23 years of Kavanattinkara boat race, Kottayam, Kerala, India. The pulmonary function tests were carried out with vitallograph compact-II spirometer. The results show a decrease in pulmonary functions "lung volumes" and "flow rates" after rowing in comparison to basal condition.