Science Vision

95-105

Authors: R. B. Muthukumaran

Nicotine, not a carcinogen per se, is one of the most addictive substances known. Tobacco smoke contains a vast number of chemicals with important biological effects in disease processes. Tobacco use is a global epidemic and the adverse health conditions including cardio-vascular diseases, atherosclerosis, and cancer are the manifestations of sustained tobacco consumption. Cancer is a major public health burden in both developed and developing countries. Tuibur, considered as ‘smokeless’ tobacco product in Mizoram, is presumed as one of the “safe” nicotine delivery media. In this mini-review, few tobacco-specific carcinogens detected in tuibur solution and their potential effects on biological systems are discussed.

113-122

Authors: Lalpawimawha, B. Lalruatfela

According to the National Cancer Registry Programme, Mizoram has the highest cancer incidence among the states of India. Lung cancer has been found to be very common among the Mizos and its etiology has never been scientifically analyzed in this high cancer incidence population. A hospital based case-control study was conducted during March, 2014 to February, 2016. The study involved 106 histologically confirmed lung cancer patients and 212 matched cancer-free subjects acting as controls, all with the same ethnic background, i.e. Mizo. Among the cases, the risk of lung cancer was significantly elevated among ex-smokers (OR, 4.69; 95% CI, 2.36-9.32), but not among current smokers. Higher risks were seen for zozial smokers (OR, 2.51; 95% CI, 1.28-4.92). The increased risk was apparent among subjects who had smoked for ≥40 years. Exposure to environmental smoke at home and workplace were significantly associated with an increased risk of lung cancer. Higher risk was also observed for previous diagnosis of asthma (OR, 4.62; 95% CI, 1.75-12.23). Lower consumption of alcohol related with decreased risk of lung cancer (OR, 0.87; 95% CI, 0.37-2.05). Tobacco smoking was found to be the primary factor for developing lung cancer. Certain occupations like the transport industry, farming, carpentry or automobile works were found to increase the risk of lung cancer. Prior affliction with tuberculosis might also have the potential to increase the risk. However, low and moderate consumption of alcohol leads to decrease risk of lung cancer.

135-143

Authors: B. Zodinpuii, Lalnuntluanga, H. Lalthanzara

Shifting cultivation is one of the main forms of crop husbandry in the hilly northeast India and is known to change the physico-chemical properties of soil. Data of soil organic carbon (SOC) in relation to shifting cultivation is not available in Mizoram. The study was conducted in an experimental plot of 1-acre area in the natural forest at Khawrihnim village located about 50 km south-west of Aizawl, Mizoram. Five random soil samples each were collected from shifting cultivation (experimental EXPTL) and natural forest (control CTRL) sites at monthly intervals between 2013 and 2015 at three different soil strata (i.e. 0-10 cm, 10-20 cm and 20-30 cm). SOC was estimated in percent by rapid dichromate oxidation method. Shifting cultivation has positive significant effect on SOC content. Compare to pre- and post-Jhum cultivation, the Two-Way ANOVA indicates significant increased of SOC (p<0.05) in the jhum cultivation year, which may be due to burning effect and the weeding practice that coincides with the onset of monsoon rains. The onset of monsoon after the burning of slashed vegetation and the first weeding accelerate the decomposition rate and soil microbial activity. The average of SOC in the surface layer increased from first year to third year by 1.34%. However, significant decreased of SOC content with increased in soil depth (p<0.001) was also recorded in both EXPTL and CTRL sites.