Under-diagnosis and under-ascertainment of cases may be the reasons for low childhood cancer incidence in rural India

Cancer statistics from India revealed that childhood cancer incidence is lesser in rural than urban India. This might be due to under-diagnosis or under-ascertainment of cases or could even be true. With registries able to explicitly measure and appropriately streamline the ascertainment of cases to comply with acceptable standards, it is under-diagnosis that is variable and highly influenced by development of or accessibility to specialized centres in or around the registry area. This is reflected implicitly by marked variation in incidence between different populations in India: weighted age standardized rates of all childhood cancers together was the highest (108 per million) in metropolitan areas, followed by other urban (86) and rural (53) areas in that order. A childhood cancer registry focusing on pertinent data collection and specific epidemiological studies is desirable to explain the variations in incidence and outcome of childhood cancers in India.     

Modelling of the regulation of the hilA promoter of type three secretion system of Salmonella enterica serovar Typhimurium

One of the most common modes of secretion of toxins in gram-negative bacteria is via the type three secretion system (TTSS), which enables the toxins to be specifically exported into the host cell. The hilA gene product is a key regulator of the expression of the TTSS located on the pathogenicity island (SPI-1) of Salmonella enterica serovar Typhimurium. It has been proposed earlier that the regulation of HilA expression is via a complex feedforward loop involving the transactivators HilD, HilC and RtsA. In this paper, we have constructed a mathematical model of regulation of hilA-promoter by all the three activators using two feedforward loops. We have modified the model to include additional complexities in regulation such as the proposed positive feedback and cross regulations of the three transactivators. Results of the various models indicate that the basic model involving two Type I coherent feedforward loops with an OR gate is sufficient to explain the published experimental observations. We also discuss two scenarios where the regulation can occur via monomers or heterodimers of the transactivators and propose experiments that can be performed to distinguish the two modes of regulator function. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Effect of tobacco chewing,tobacco smoking and alcohol on all-cause and cancer mortality: A cohort study from Trivandrum,India

Objective: To study the risk of all-cause, cancer and tobacco-related cancer mortality associated with tobacco chewing, tobacco smoking and alcohol use. Design: Prospective community-based cohort study initiated in 1996. Participants: 167 343 adult subjects, aged 34 and older, living in 13 panchayaths (rural municipal administrative units) in South India, were regularly followed-up for a mean duration of 6.5 years. Main outcome measures: Mortality from all-causes, all cancer and tobacco-related cancer. Results: The mortality risks associated with chewing (and 95% confidence intervals), after adjusting for age, sex, socio-economic and dietary variables, and for other habits, were 0.90 (0.86–0.94) for all-cause, 1.07 (0.94–1.22) for cancer and 1.22 (1.04–1.44) for tobacco-related cancer; with smoking the respective mortality risks were 1.31 (1.24–1.39), 1.63 (1.37–1.94) and 1.68 (1.36–2.08); and with alcohol use the risks were 1.13 (1.06–1.20), 1.32 (1.11–1.57) and 1.47 (1.19–1.80), respectively. Reduced risk of all-cause mortality by chewing was observed only in the 60–84 years old group (0.90 (0.85–0.94)), and detrimental effects of chewing on cancer mortality were shown in the young and middle-age groups: 34–39 years old (1.33 (0.67–2.65)), and 40–59 years old (1.26 (1.03–1.55)). Conclusion: Tobacco in any form and alcohol uses were harmful and a higher quality of life could be achieved by avoiding these habits. Given the demographic, epidemiological and economic transitions and changes in pattern of tobacco and alcohol use in India, the health loss from the tobacco and alcohol will grow even larger, unless effective interventions and policies to reduce these habits are implemented.     

Modelling of microbial growth for sequential utilization in a multisubstrate environment

Microbial growth in multisubstrate environments is posed as a problem of multivariable constraint optimization. The optimization aims at maximizing the instantaneous growth rate of cells. The model developed for microbial growth using this hypothesis involves simple representation of complex cell structure as an optimization function which regulates the interplay of cellular machinery. The model parameters are estimated using single substrate growth data. Model simulation fits very well with earlier published experimental data of bacterial growth of Klensiella oxytoca on a variety of sugar mixtures involving glucose, fructose, lactose, and xylose. Moreover, the model is also able to predict the diauxic growth of Saccharomyces cerevisiae on glucose and galactose. One of the interesting outcomes of the above representation is the ability to prove analytically that the growth on the mixture of two sugars will be diauxic if one of the substrates has a very low K_s value and a high μ_m value.