Vaccination impact on impending HIV-COVID-19 dual epidemic with autogenous behavior modification: Hill-type functional response and premeditated optimization technique

An HIV-COVID-19 co-infection dynamics is modeled mathematically assimilating the vaccination mechanism that incorporates endogenous modification of human practices generated by the COVID-19 prevalence, absorbing the relevance of the treatment mechanism in suppressing the co-infection burden. Envisaging a COVID-19 situation, the HIV-subsystem is analyzed by introducing COVID-19 vaccination for the HIV-infected population as a prevention, and the "vaccination influenced basic reproduction number" of HIV is derived. The mono-infection systems experience forward bifurcation that evidences the persistence of diseases above unit epidemic thresholds. Delicate simulation methodologies are employed to explore the impacts of baseline vaccination, prevalence-dependent spontaneous behavioral change that induces supplementary vaccination, and medication on the dual epidemic. Captivatingly, a paradox is revealed showing that people start to get vaccinated at an additional rate with the increased COVID-19 prevalence, which ultimately diminishes the dual epidemic load. It suggests increasing the baseline vaccination rate and the potency of propagated awareness. Co-infection treatment needs to be emphasized parallelly with single infection medication under dual epidemic situations. Further, an optimization technique is introduced to the co-infection model integrating vaccination and treatment control mechanisms, which approves the strategy combining vaccination with awareness and medication as the ideal one for epidemic and economic gain. Conclusively, it is manifested that waiting frivolously for any anticipated outbreak, depending on autogenous behavior modification generated by the increased COVID-19 prevalence, instead of elevating vaccination campaigns and the efficacy of awareness beforehand, may cause devastation to the population under future co-epidemic conditions.

Bifurcation analysis of autonomous and nonautonomous modified Leslie-Gower models

In ecological systems, the predator-induced fear dampens the prey's birth rate; yet, it fails to extinguish their population, as they endure and survive even under significant fear-induced costs. In this study, we unveil a modified Leslie-Gower predator-prey model by incorporating the fear of predators, cooperative hunting, and predator-taxis sensitivity. We embark upon an exploration of the positivity and boundedness of solutions, unearthing ecologically viable equilibrium points and their stability conditions governed by the model parameters. Delving deeper, we unravel the scenario of transcritical, saddle-node, Hopf, Bogdanov-Takens, and generalized-Hopf bifurcations within the system's intricate dynamics. Additionally, we observe the bistable nature of the system under some parametric conditions. Further, the nonautonomous extension of our model introduces the intriguing interplay of seasonality in some crucial parameters. We establish a set of sufficient conditions that guarantee the permanence of the seasonally driven system. By conducting a numerical study on the seasonally forced model, we observe a myriad of phenomena manifesting the predator-prey dynamics. Notably, periodic solutions, higher periodic solutions, and bursting patterns emerge, alongside intriguing chaotic dynamics. Specifically, seasonal variations of the predator-taxis sensitivity and hunting cooperation can lead to the extinction of prey species and even the control of chaotic (higher periodic) solutions through the generation of a simple periodic solution. Remarkably, the seasonal forcing has the capacity to govern the chaotic behavior, leading to an exceptionally quasi-periodic arrangement in both prey and predator populations.

Fear effect in a three-species food chain model with generalist predator

Within the framework of a food web, the foraging behavior of meso-carnivorous species is influenced by fear responses elicited by higher trophic level species, consequently diminishing the fecundity of these species. In this study, we investigate a three-species food chain model comprising of prey, an intermediate predator, and a top predator. We assume that both the birth rate and intraspecies competition of prey are impacted by fear induced by the intermediate predator. Additionally, the foraging behavior of the intermediate predator is constrained due to the presence of the top predator. It is essential to note that the top predators exhibit a generalist feeding behavior, encompassing food sources beyond the intermediate predators. The study systematically determines all feasible equilibria of the proposed model and conducts a comprehensive stability analysis of these equilibria. The investigation reveals that the system undergoes Hopf bifurcation concerning various model parameters. Notably, when other food sources significantly contribute to the growth of the top predators, the system exhibits stable behavior around the interior equilibrium. Our findings indicate that the dynamic influence of fear plays a robust role in stabilizing the system. Furthermore, a cascading effect within the system, stemming from the fear instigated by top predators, is observed and analyzed. Overall, this research sheds light on the intricate dynamics of fear-induced responses in shaping the stability and behavior of multi-species food web systems, highlighting the profound cascading effects triggered by fear mechanisms in the ecosystem.

Stability switches and chaos induced by delay in a reaction-diffusion nutrient-plankton model

In this paper, we investigate a reaction-diffusion model incorporating dynamic variables for nutrient, phytoplankton, and zooplankton. Moreover, we account for the impact of time delay in the growth of phytoplankton following nutrient uptake. Our theoretical analysis reveals that the time delay can trigger the emergence of persistent oscillations in the model via a Hopf bifurcation. We also analytically track the direction of Hopf bifurcation and the stability of the bifurcating periodic solutions. Our simulation results demonstrate stability switches occurring for the positive equilibrium with an increasing time lag. Furthermore, the model exhibits homogeneous periodic-2 and 3 solutions, as well as chaotic behaviour. These findings highlight that the presence of time delay in the phytoplankton growth can bring forth dynamical complexity to the nutrient-plankton system of aquatic habitats.

A mathematical model for the impact of disinfectants on the control of bacterial diseases

Here, we investigate a mathematical model to assess the impact of disinfectants in controlling diseases that spread in the population via direct contacts with the infected persons and also due to bacteria present in the environment. We find that the disease-free and endemic equilibria of the system are related via a transcritical bifurcation whose direction is forward. Our numerical results show that controlling the transmissions of disease through direct contacts and bacteria present in the environment can help in reducing the disease prevalence. Moreover, fostering the recovery rate and the death rate of bacteria play significant roles in disease eradication. Our numerical observations convey that reducing the bacterial density at the source discharged by the infected population through the use of chemicals has prominent effect in disease control. Overall, our findings manifest that the disinfectants of high quality can completely control the bacterial density and the disease outbreak.

Investigation of a nutrient-plankton model with stochastic fluctuation and impulsive control

In this paper, we investigate a stochastic nutrient-plankton model with impulsive control of the nutrient concentration and zooplankton population. Analytically, we find that the population size is nonnegative for a sufficiently long time. We derive some sufficient conditions for the existence of stable periodic oscillations, which indicate that the plankton populations will behave periodically. The numerical results show that the plankton system experiences a transition from extinction to the coexistence of species due to the emergence of impulsive control. Additionally, we observe that the nutrient pulse has a stronger relationship with phytoplankton growth than the zooplankton pulse. Although the frequency of impulsive control and appropriate environmental fluctuations can promote the coexistence of plankton populations, an excessive intensity of noise can result in the collapse of the entire ecosystem. Our findings may provide some insights into the relationships among nutrients, phytoplankton and zooplankton in a stochastic environment.

Impacts of transpiration of agricultural crops and seeding on rainfall: Implications from a mathematical model

As the source of replenishment, rainfall has an extensive impact because its variability shapes biologically efficient pulses of soil moisture recharge across layers from rainfall events. In this paper, a mathematical model is proposed to explore the importance of transpiration from agricultural crops and aerosols on the pattern of rainfall. For the system without seeding, the simulation results show destabilizing roles of parameters related to formation of cloud drops due to transpiration of agricultural crops, formation of raindrops due to cloud drops and growth of agricultural crops due to rain. The model without seeding is extended to its stochastic counterpart to encapsulate the uncertainty observed in some important parameters. We observe the variability in the system’s variables and found their distributions at certain fixed times, which explore the importance of stochasticity in the system. Our findings show that transpiration through agricultural crops plays an important role in cloud formation, and thus, affects the effectiveness of different rainfall events. Moreover, the combined actions of transpiration and seeding are much more beneficial in producing rain. Finally, we see the behavior of system by considering seasonal variations of some rate parameters.

Impact of saturated treatments on HIV-TB dual epidemic as a consequence of COVID-19: optimal control with awareness and treatment

In this study, we propose an HIV-TB co-infection model by considering the treatment provision limitation induced by recent COVID-19 pandemic that impacts this dual epidemic immensely, assimilating the significance of educational attempts. We analyze the model and its submodels with single infections individually. We obtain the awareness-induced basic reproduction numbers and discuss the global stability of disease-free equilibrium when provision limitation is zero. We observe that the submodels exhibit forward as well as backward bifurcations under provision restriction. Further, we derive thresholds for resource limitations regulating the dynamical behavior of the systems while analyzing the stability of endemic equilibrium of the models with single infections. Sophisticated simulation approaches are implemented to discover the influences of provision-restricted medication and awareness on dual epidemic. Our findings convey the persistence of co-infection though the basic reproduction number is below unity, if the provision restriction remains uncurbed. An observable insight is that, in spite of having epidemic threshold less than unity and no limitation in TB treatment, co-infection relapses and persists in the population, when there is no awareness attempt. Numerical findings emphasize the urgent need of increased treatment accessibility and importance of awareness in the current situation. Moreover, an optimization problem incorporating treatment and awareness controls is formulated and solved to find the ideal strategy to manage HIV-TB co-epidemic that recommends to diminish the medical resource limitation to get the enormous impact in dominating the adversity caused by COVID-19.

A systematic study of autonomous and nonautonomous predator-prey models for the combined effects of fear, refuge, cooperation and harvesting

In the present study, we investigate the roles of fear, refuge and hunting cooperation on the dynamics of a predator-prey system, where the predator population is subject to harvesting at a nonlinear rate. We also focus on the effects of seasonal forcing by letting some of the model parameters to vary with time. We rigorously analyze the autonomous and nonautonomous models mathematically as well as numerically. Our simulation results show that the birth rate of prey and the fear of predators causing decline in it, and harvesting of predators first destabilize and then stabilize the system around the coexistence of prey and predator; if the birth rate of prey is very low, both prey and predator populations extinct from the ecosystem, and for a range of this parameter, only the prey population survive. The fear of predators responsible for increase in the intraspecific competition among the prey species and the refuge behavior of prey have tendency to stabilize the system, whereas the cooperative behavior of predators during the hunting time destroys stability in the ecosystem. Numerical investigations of the seasonally forced model showcase the appearances of periodic solution, higher periodic solutions, bursting patterns and chaotic dynamics.

Impact of social media advertisements on the transmission dynamics of COVID-19 pandemic in India

In this paper, we propose a mathematical model to assess the impact of social media advertisements in combating the coronavirus pandemic in India. We assume that dissemination of awareness among susceptible individuals modifies public attitudes and behaviours towards this contagious disease which results in reducing the chance of contact with the coronavirus and hence decreasing the disease transmission. Moreover, the individual's behavioral response in the presence of global information campaigns accelerate the rate of hospitalization of symptomatic individuals and also encourage the asymptomatic individuals for conducting health protocols, such as self-isolation, social distancing, etc. We calibrate the proposed model with the cumulative confirmed COVID-19 cases for the Republic of India. We estimate eight epidemiologically important parameters, and also the size of basic reproduction number for India. We find that the basic reproduction number for India is greater than unity, which represents the substantial outbreak of COVID-19 in the country. Sophisticated techniques of sensitivity analysis are employed to determine the impacts of model parameters on basic reproduction number and symptomatic infected population. Our results reveal that to reduce disease burden in India, non-pharmaceutical interventions strategies should be implemented effectively to decrease basic reproduction number below unity. Continuous propagation of awareness through the internet and social media platforms should be regularly circulated by the health authorities/government officials for hospitalization of symptomatic individuals and quarantine of asymptomatic individuals to control the prevalence of disease in India.

A systematic study of autonomous and nonautonomous predator-prey models for the combined effects of fear, refuge, cooperation and harvesting

In the present study, we investigate the roles of fear, refuge and hunting cooperation on the dynamics of a predator-prey system, where the predator population is subject to harvesting at a nonlinear rate. We also focus on the effects of seasonal forcing by letting some of the model parameters to vary with time. We rigorously analyze the autonomous and nonautonomous models mathematically as well as numerically. Our simulation results show that the birth rate of prey and the fear of predators causing decline in it, and harvesting of predators first destabilize and then stabilize the system around the coexistence of prey and predator; if the birth rate of prey is very low, both prey and predator populations extinct from the ecosystem, and for a range of this parameter, only the prey population survive. The fear of predators responsible for increase in the intraspecific competition among the prey species and the refuge behavior of prey have tendency to stabilize the system, whereas the cooperative behavior of predators during the hunting time destroys stability in the ecosystem. Numerical investigations of the seasonally forced model showcase the appearances of periodic solution, higher periodic solutions, bursting patterns and chaotic dynamics.

Bifurcations, chaos, and multistability in a nonautonomous predator-prey model with fear

Classical predator-prey models usually emphasize direct predation as the primary means of interaction between predators and prey. However, several field studies and experiments suggest that the mere presence of predators nearby can reduce prey density by forcing them to adopt costly defensive strategies. Adoption of such kind would cause a substantial change in prey demography. The present paper investigates a predator-prey model in which the predator's consumption rate (described by a functional response) is affected by both prey and predator densities. Perceived fear of predators leads to a drop in prey's birth rate. We also consider both constant and time-varying (seasonal) forms of prey's birth rate and investigate the model system's respective autonomous and nonautonomous implementations. Our analytical studies include finding conditions for the local stability of equilibrium points, the existence, direction of Hopf bifurcation, etc. Numerical illustrations include bifurcation diagrams assisted by phase portraits, construction of isospike and Lyapunov exponent diagrams in bi-parametric space that reveal the rich and complex dynamics embedded in the system. We observe different organized periodic structures within the chaotic regime, multistability between multiple pairs of coexisting attractors with intriguing basins of attractions. Our results show that even relatively slight changes in system parameters, perturbations, or environmental fluctuations may have drastic consequences on population oscillations. Our observations indicate that the fear effect alters the system dynamics significantly and drives an otherwise irregular system toward regularity.

Delay in budget allocation for vaccination and awareness induces chaos in an infectious disease model

In this paper, we propose a model to assess the impacts of budget allocation for vaccination and awareness programs on the dynamics of infectious diseases. The budget allocation is assumed to follow logistic growth, and its per capita growth rate increases proportional to disease prevalence. An increment in per-capita growth rate of budget allocation due to increase in infected individuals after a threshold value leads to onset of limit cycle oscillations. Our results reveal that the epidemic potential can be reduced or even disease can be eradicated through vaccination of high quality and/or continuous propagation of awareness among the people in endemic zones. We extend the proposed model by incorporating a discrete time delay in the increment of budget allocation due to infected population in the region. We observe that multiple stability switches occur and the system becomes chaotic on gradual increase in the value of time delay.

A delay non-autonomous model for the combined effects of fear, prey refuge and additional food for predator

In this paper, we investigate the combined effects of fear, prey refuge and additional food for predator in a predator-prey system with Beddington type functional response. We observe oscillatory behaviour of the system in the absence of fear, refuge and additional food whereas the system shows stable dynamics if anyone of these three factors is introduced. After analysing the behaviour of system with fear, refuge and additional food, we find that the system destabilizes due to fear factor whereas refuge and additional food stabilize the system by killing persistent oscillations. We extend our model by considering the fact that after sensing the chemical/vocal cue, prey takes some time for assessing the predation risk. The delayed system shows chaotic dynamics through multiple stability switches for increasing values of time delay. Moreover, we see the impact of seasonal change in the level of fear on the delayed as well as non-delayed system.

A nonautonomous mathematical model to assess the impact of algae on the abatement of atmospheric carbon dioxide

The world’s oceans have played an important role in sequestering atmospheric carbon dioxide through solubility and the action of algae. Fixation of atmospheric carbon dioxide by photoautotrophic algal cultures has the potential to diminish the release of carbon dioxide into the atmosphere, thereby helping to alleviate the trend toward global warming. This work investigates the role of algae in controlling the level of atmospheric carbon dioxide. Partial Rank Correlation Coefficients (PRCCs) technique is used to address how the concentration of atmospheric carbon dioxide is affected by changes in a specific parameter disregarding the uncertainty over the rest of the model parameters. Parameters related to algal growth are shown to significantly reduce the level of atmospheric CO2. Further, we explore the dynamics of nonautonomous system by incorporating the seasonal variations of some ecologically important model parameters. Our nonautonomous system exhibits globally attractive positive periodic solution, and also the appearance of double periodic solution is observed. Moreover, by letting the seasonally forced parameters as almost periodic functions of time, we show almost periodic behavior of the system. Our findings suggest that the policy makers should focus on continuous addition of nutrients in the ocean to accelerate the algal growth thereby reducing the level of carbon dioxide in the atmosphere.

Dynamics of coronavirus pandemic: effects of community awareness and global information campaigns

The effects of social media advertisements together with local awareness in controlling COVID-19 are explored in the present investigation by means of a mathematical model. The expression for the basic reproduction number is derived. Sufficient conditions for the global stability of endemic equilibrium are obtained. We perform sensitivity analysis to identify the key parameters of the model having great impacts on the prevalence and control of COVID-19. We calibrate the proposed model to fit the data set of COVID-19 cases for India. Our simulation results show that dissemination rate of awareness among susceptible individuals at community level and individual level plays pivotal role in curtailing the COVID-19 disease. Moreover, we observe that the global information distributing from social media and local awareness coming from mouth-to-mouth communication between unaware susceptible and aware people, together with hospitalization of symptomatic individuals and quarantine of asymptomatic individuals, are much beneficial in reducing COVID-19 cases in India. Our study suggests that both global and local awareness must be implemented effectively to manage the burden of COVID-19 pandemic.

A mathematical model for the impacts of face mask, hospitalization and quarantine on the dynamics of COVID-19 in India: deterministic vs. stochastic

In this paper, we propose a mathematical model to assess the impacts of using face masks, hospitalization of symptomatic individuals and quarantine of asymptomatic individuals in combating the COVID-19 pandemic in India. We calibrate the proposed model to fit the four data sets, viz. data for the states of Maharashtra, Delhi, Tamil Nadu and overall India, and estimate the rate of infection of susceptible with symptomatic population and recovery rate of quarantined individuals. We also estimate basic reproduction number to illustrate the epidemiological status of the regions under study. Our simulations infer that the infective population will be on increasing curve for Maharashtra and India, and settling for Tamil Nadu and Delhi. Sophisticated techniques of sensitivity analysis are employed to determine the impacts of model parameters on basic reproduction number and symptomatic infected individuals. Our results reveal that to curtail the disease burden in India, specific control strategies should be implemented effectively so that the basic reproduction number is decreased below unity. The three control strategies are shown to be important preventive measures to lower disease transmission rate. The model is further extended to its stochastic counterpart to encapsulate the variation or uncertainty observed in the disease transmissibility. We observe the variability in the infective population and found their distribution at certain fixed time, which shows that for small populations, the stochasticity will play an important role.

Maternal Spirulina supplementation during pregnancy and lactation partially prevents oxidative stress, glial activation and neuronal damage in protein malnourished F1 progeny

Protein malnutrition (PMN) is a global health issue but most prevalent in Africa and Asia. It exerts detrimental effect on structural and physiological aspects of hippocampal circuitry. Despite accumulating evidence for PMN induced changes in nervous system, relatively very little is known about how maternal nutritional supplementation during malnutrition affects glial cells and neurons. Herein, we aimed to investigate the effects of maternal Spirulina supplementation against PMN induced oxidative stress, reactive gliosis and neuronal damage in hippocampus of F1 progeny. Three months old healthy Sprague Dawley females (n = 24) were shifted to normoprotein (NC; 20% protein) and low protein (LP; 8% protein) diets 15 days before conception. The NC and LP group females were subdivided into two groups according to Spirulina supplementation (400 mg/kg/b.wt. orally throughout gestation and lactation period): normal control with Spirulina (NC SPI) and low protein with Spirulina supplemented group (LP SPI). F1 progeny born were used in present study. Thus, building on earlier results of ameliorated neurobehavioral and cognitive abilities in Spirulina supplemented protein deprived rats, the present study incorporates neurochemical and morphometric analysis of glial cells and neurons and revealed that maternal Spirulina consumption partially prevented the PMN associated neuropathological alterations in terms of attenuated oxidative brain damage, reduced reactive gliosis and apoptotic cell population, improved dendritic branch complexity with few damaged neurons and enhanced mushroom shaped spine density. The results suggest that cellular changes in hippocampus after PMN are partially restored after maternal Spirulina supplementation and one could envision intervention approaches using Spirulina against malnutrition.

Modeling the effect of literacy and social media advertisements on the dynamics of infectious diseases

Education empowers humans and gets them ready to face challenges of life efficiently. Literacy and social media campaigns make people aware of the tools and techniques requisite for protection against the emerging diseases. In this paper, we investigate the combined impacts of literacy and social media on the dynamics of infectious diseases spreading through direct contact. Normalized forward sensitivity indices explore the impacts of parameters on basic reproduction number. We perform global sensitivity analysis for the infective population with respect to some controllable epidemiologically important parameters. If the growth rate of broadcasting informations through social media is very high, the system shows limit cycle oscillations. On the other hand, the baseline number of social media advertisements stabilize the system by evacuating persistent oscillations and ultimately settling the system from stable endemic equilibrium to stable disease-free state. The dissemination of awareness among literate people also suppresses the prevalence of limit cycle oscillations and drives the system to disease-free zone. An extension in model is made by assuming the growth rate of social media advertisements as periodic function of time. The simulation results show that the nonautonomous system showcases periodic as well as higher periodic solutions on the increase in the growth rate of advertisements. Our results evoke that media and education play a tremendous role in mounting awareness among the population leading to elimination of disease in the society.

Classification of Pigeonpea (Cajanus cajan (L.) Millsp.) Genotypes for Zinc Efficiency

Pigeonpea (Cajanus cajan (L.) Millsp.) is grown globally for its protein-rich seed. However, low availability of soil zinc (Zn) adversely affects the seed yield of pigeonpea. The present study was therefore conducted to assess the Zn efficiency of pigeonpea genotypes based on seed yield and seed Zn uptake efficiency. Field experiments were conducted at the Indian Council of Agricultural Research–Indian Institute of Soil Science, Bhopal, India with twenty different pigeonpea genotypes and two levels of Zn application under a split-plot design. The two levels of Zn were low (without application of Zn fertilizer) and high (with application of 20 kg Zn ha⁻¹ (as ZnSO₄∙7H2O) as basal soil application, in conjunction with three foliar sprays of 0.50% (w/v) ZnSO₄∙7H₂O aqueous solution) (with 0.25% lime as neutralizing agent) at flowering, pod formation, and pod filling stages). Application of Zn improved plant height, branches plant⁻¹, pods plant⁻¹, seeds pod⁻¹, and 100 seed weight of pigeonpea genotypes differently. The mean seed yield, seed Zn concentration, and seed Zn uptake of the genotypes increased from 1.71 to 2.12 t ha⁻¹, 32.4 to 43.0 mg kg⁻¹, and 54.9 to 90.6 g ha⁻¹, respectively, with application of Zn. The seed yield efficiency index (SYEI) and Zn uptake efficiency index (ZUEI) of pigeonpea genotypes varied from 67.0 to 92.5 and from 47.0 to 69.9, respectively. Based on SYEI and ZUEI, the genotypes were classified as efficient and responsive (Virsa Arhar-1, GT-1, GT-101, SKNP 05-05, BDN-2, AAUT 2007-04, BSMR 853, T 15-15, DT 23, Pusa 9), efficient and non-responsive (ICPL 87119, PKV Trombay), inefficient and responsive (AKT 8811, Hisar Paras), and inefficient and non-responsive (AAUT 2007-10, JKM 7, Hisar Manak, C 11, Hisar HO2-60, GAUT 93-17). The efficient and responsive genotypes are the most useful as they yield well under low soil Zn conditions and also respond to Zn fertilizer application. The inefficient and responsive genotypes could be utilized for plant breeding programs by plant breeders for identification and utilization of responsive traits.

Modeling the avoidance behavior of zooplankton on phytoplankton infected by free viruses

In any ecosystem, chaotic situations may arise from equilibrium state for different reasons. To overcome these chaotic situations, sometimes the system itself exhibits some mechanisms of self-adaptability. In this paper, we explore an eco-epidemiological model consisting of three aquatic groups: phytoplankton, zooplankton, and marine free viruses. We assume that the phytoplankton population is infected by external free viruses and zooplankton get affected on consumption of infected phytoplankton; also, the infected phytoplankton do not compete for resources with the susceptible one. In addition, we model a mechanism by which zooplankton recognize and avoid infected phytoplankton, at least when susceptible phytoplankton are present. The zooplankton extinction chance increases on increasing the force of infection or decreasing the intensity of avoidance. Further, when the viral infection triggers chaotic dynamics, high zooplankton avoidance intensity can stabilize again the system. Interestingly, for high avoidance intensity, nutrient enrichment has a destabilizing effect on the system dynamics, which is in line with the paradox of enrichment. Global sensitivity analysis helps to identify the most significant parameters that reduce the infected phytoplankton in the system. Finally, we compare the dynamics of the system by allowing the infected phytoplankton also to share resources with the susceptible phytoplankton. A gradual increase of the virus replication factor turns the system dynamics from chaos to doubling state to limit cycle to stable state and the system finally settles down to the zooplankton-free equilibrium point. Moreover, on increasing the intensity of avoidance, the system shows a transcritical bifurcation from the zooplankton-free equilibrium to the coexistence steady state and remains stable thereafter.

Chaos in a nonautonomous eco-epidemiological model with delay

In this paper, we propose and analyze a nonautonomous predator-prey model with disease in prey, and a discrete time delay for the incubation period in disease transmission. Employing the theory of differential inequalities, we find sufficient conditions for the permanence of the system. Further, we use Lyapunov's functional method to obtain sufficient conditions for global asymptotic stability of the system. We observe that the permanence of the system is unaffected due to presence of incubation delay. However, incubation delay affects the global stability of the positive periodic solution of the system. To reinforce the analytical results and to get more insight into the system's behavior, we perform some numerical simulations of the autonomous and nonautonomous systems with and without time delay. We observe that for the gradual increase in the magnitude of incubation delay, the autonomous system develops limit cycle oscillation through a Hopf-bifurcation while the corresponding nonautonomous system shows chaotic dynamics through quasi-periodic oscillations. We apply basic tools of non-linear dynamics such as Poincaré section and maximum Lyapunov exponent to confirm the chaotic behavior of the system.

Effects of zooplankton selectivity on phytoplankton in an ecosystem affected by free-viruses and environmental toxins

In the present study, we investigate the selective feeding of zooplankton on phytoplankton infected by free-viruses in the presence of environmental toxins in the marine ecosystem. The environmental toxins assume to decrease the growth rate of susceptible phytoplankton, and increase the death rate of infected phytoplankton and zooplankton. Global sensitivity analysis identifies important parameters of the system having crucial impact on the aquatic health. The coexistence equilibrium of the system stabilizes on increasing the parameters related to inhibition of phytoplankton growth due to environmental toxins and the force of infection, and destabilizes on increasing the carrying capacity of susceptible phytoplankton and preference of zooplankton on infected phytoplankton. The chance of extinction of free-viruses increases on increasing the preference of zooplankton on infected phytoplankton or decreasing the force of infection. Moreover, if the input rate of environmental toxins is high, then the system becomes zooplankton-free for higher values of force of infection. On increasing the values of preference of zooplankton on infected phytoplankton, the system exhibits transition from stable coexistence to oscillations around coexistence equilibrium to oscillations around disease-free equilibrium. We observe that the presence of free-viruses and environmental toxins in the system drive zooplankton population to very low equilibrium values but the ecological balance of the aquatic food web can be maintained by modulating the decay (depletion) rate of free-viruses (environmental toxins).

A mathematical study to control Guinea worm disease: a case study on Chad

Global eradication of Guinea worm disease (GWD) is in the final stage but a mysterious epidemic of the parasite in dog population makes the elimination programme challenging. There is neither a vaccine nor an effective treatment against the disease and therefore intervention strategies rely on the current epidemiological understandings to control the spread of the disease. A novel mathematical model can predict the future outbreaks and it can quantify the dissemination rates of control interventions. Due to the lack of such novel models, a realistic mathematical model of GWD dynamics with human population, dog population, copepod population and the worm larvae is proposed and analyzed. Considering case data from Chad, we calibrate the model and perform global sensitivity analysis of the basic reproduction number with respect to the control parameters and copepod consumption rates. Furthermore, we investigate the impact of three control interventions: awareness of humans, isolation of infected dogs and copepod clearance from contaminated water sources. We also address the impact of combination interventions which leads to the conclusion that the combination of isolating the infected dogs and treating the contaminated ponds is a plausible way for eliminating the burden of GWD from Chad.

Rapid analysis of pharmaceutical drugs using LIBS coupled with multivariate analysis

Type 2 diabetes drug tablets containing voglibose having dose strengths of 0.2 and 0.3 mg of various brands have been examined, using laser-induced breakdown spectroscopy (LIBS) technique. The statistical methods such as the principal component analysis (PCA) and the partial least square regression analysis (PLSR) have been employed on LIBS spectral data for classifying and developing the calibration models of drug samples. We have developed the ratio-based calibration model applying PLSR in which relative spectral intensity ratios H/C, H/N and O/N are used. Further, the developed model has been employed to predict the relative concentration of element in unknown drug samples. The experiment has been performed in air and argon atmosphere, respectively, and the obtained results have been compared. The present model provides rapid spectroscopic method for drug analysis with high statistical significance for online control and measurement process in a wide variety of pharmaceutical industrial applications.

Gallbladder cancer incidence in Gwalior district of India: Five-year trend based on the registry of a regional cancer center

BACKGROUND

We have reported here the 5-year incidence (2004-2008) of gallbladder cancer (GBC) in North Central India along with its descriptive epidemiology. This provides potential clues for better prevention. The present study has also evaluated the association of ABO blood groups with GBC.

PATIENTS AND METHODS

The study comprised 742 GBC cases referred to the regional cancer hospital, Gwalior, during 2004-2008. The demographic statistics of Gwalior district was considered to calculate the relative risk and incidence rates. ABO blood group distribution amongst 90,000 healthy subjects registered in the local blood bank during 2002-2007 was taken as controls to study the association of blood groups with GBC.

RESULTS

The age-standardized total incidence rate of GBC was calculated to be 7.16/1,00,000. The relative risk of females getting GBC was 2.693 at 95% confidence interval of 2.304-3.151 (P < 0.0001). The females formed 69.5% of total cancer cases, with age-standardized incidence rate of 10/1,00,000. The mean age of male and female GBC cases was found to be 55.4 years (SD = 13, SE = 0.77) and 51.5 years (SD = 12.3, SE = 0.50), respectively. The blood groups A (P = 0.0022) and AB (P < 0.0001) had a positive association with GBC with significant level of differences in comparison to controls.

CONCLUSION

Our study provided an estimate of a 5-year incidence of GBC in North Central India for the first time. With regard to the association of risk factors like obesity, age, and urban living with GBC, the findings of the present study are contradictory to the general opinion. Blood groups A and AB were found to be associated with GBC, which would be provisional for further investigations.

Modeling the impact of awareness on the mitigation of algal bloom in a lake

The proliferation of algal bloom in water bodies due to the enhanced concentration of nutrient inflow is becoming a global issue. A prime reason behind this aquatic catastrophe is agricultural runoff, which carries a large amount of nutrients that make the lakes more fertile and cause algal blooms. The only solution to this problem is curtailing the nutrient loading through agricultural runoff. This could be achieved by raising awareness among farmers to minimize the use of fertilizers in their farms. In view of this, in this paper, we propose a mathematical model to study the effect of awareness among the farmers of the mitigation of algal bloom in a lake. The growth rate of awareness among the farmers is assumed to be proportional to the density of algae in the lake. It is further assumed that the presence of awareness among the farmers reduces the inflow rate of nutrients through agricultural runoff and helps to remove the detritus by cleaning the bottom of the lake. The results evoke that raising awareness among farmers may be a plausible factor for the mitigation of algal bloom in the lake. Numerical simulations identify the most critical parameters that influence the blooms and provide indications to possibly mitigate it.

Molecular characterization and expression analysis of hsp60 gene homologue of sheep blowfly, Lucilia cuprina

The 60kDa heat shock protein (Hsp60) or chaperonin is one among the highly conserved families of heat shock proteins, known to be involved in variety of cellular activities, including protein folding, thermal protection, etc. In this study we sequence characterized hsp60 gene homologue of Lucilia cuprina, isolated and cloned from the genomic library as well as by genomic PCR, followed by RACE- PCR. The L. cuprina hsp60 gene/protein expression pattern was analyzed in various tissues, either at normal temperature (25±1°C) or after exposure to heat stress (42°C). The analysis of nucleotide sequence of Lchsp60 gene revealed absence of intron and the nuclear localizing signal (NLS). The deduced amino acid sequence showed presence of unique conserved sequences, such as those for mitochondrial localization, ATP binding, etc. Unlike Drosophila, Lucilia showed presence of only one isoform, i.e., hsp60A. Phylogenetic analysis of hsp60 gene homologues from different species revealed Lchsp60 to have >88.36% homology with D. melanogaster, 76.86% with L. sericata, 58.31% with mice, 57.99% with rat, and 57.72% with human. Expression analysis using Real Time PCR and fluorescence imaging showed significant enhancement in the expression level of Lchsp60 upon heat stress in a tissue specific manner, indicating its likely role in thermo-tolerance as well as in normal cellular activities.

Spatial dynamics of a nutrient-phytoplankton system with toxic effect on phytoplankton

The production of toxins by some species of phytoplankton is known to have several economic, ecological, and human health impacts. However, the role of toxins on the spatial distribution of phytoplankton is not well understood. In the present study, the spatial dynamics of a nutrient-phytoplankton system with toxic effect on phytoplankton is investigated. We analyze the linear stability of the system and obtain the condition for Turing instability. In the presence of toxic effect, we find that the distribution of nutrient and phytoplankton becomes inhomogeneous in space and results in different patterns, like stripes, spots, and the mixture of them depending on the toxicity level. We also observe that the distribution of nutrient and phytoplankton shows spatiotemporal oscillation for certain toxicity level.

Heme oxygenase-1 gene variants and hyperbilirubinemia risk in North Indian newborns

Heme oxygenase-1 (HO-1) is a rate-limiting enzyme in bilirubin metabolism, and its genetic variant may modulate hyperbilirubinemia risk in neonates. The aim of the present study was to assess the association between heme oxygenase-1 gene variants and hyperbilirubinemia risk in Indian newborns. In a prospective case-control study, we analyzed (GT)n repeats and g.-413A>T variant of HO-1 gene and UGT1A1 gene variants in 100 case newborns with total serum bilirubin (TSB) levels exceeding 95th percentile and 100 control newborns with TSB levels below 75th percentile on the hour-specific bilirubin nomogram of the American Academy of Pediatrics. Study population consisted of term (37-41 weeks) and late preterm (34-36 weeks) newborns during the first 2 weeks of age. In our analysis, the (GT)n allele was highly polymorphic, ranging in number from 15 to 40. The incidence of short (GT)n allele (≤ 20) was significantly higher in neonates with hyperbilirubinemia than in controls. Although g.-413A>T variant was widely prevalent in the study population, no difference was noted in its prevalence between cases and controls. Short (GT)n repeats of HO-1 gene, c.211G>A variant of UGT1A1 gene, and excessive weight loss were independent risk factors for neonatal hyperbilirubinemia. In the presence of two or more risk factors, the odds of developing neonatal hyperbilirubinemia were high. Shorter (GT)n genotype in the promoter region of HO-1 gene is significantly associated with hyperbilirubinemia risk in Indian newborns. This genotype may interact with other genetic and clinical risk factors to further potentiate hyperbilirubinemia risk in newborns.

Low birthweight (LBW) and neonatal hyperbilirubinemia (NNH) in an Indian cohort: association of homocysteine, its metabolic pathway genes and micronutrients as risk factors

Background & Aims

Indian subcontinent has the highest child mortality rates along with a very high frequency of low birthweight (LBW). Folate and vitamin B12 (Vit-B12) are necessary during foetal development and their deficiency prevalence in Indians is very high. The objective of the present paper is to assess whether foetal homocysteine (Hcy)/folate metabolic pathway genes, their cofactors and homocysteine level independently (or collectively) predispose children to Low birth weight.

Methods

Cord blood was collected for the study. Frequency of 5 SNPs in 4-Hcy-pathway genes, and levels of Hcy, Vit-B12 and folate were evaluated.

Results

Of the 421 newborns recruited for the study, 38% showed low birth weight (<2.5kg) and 16% were preterm babies. 101 neonates developed neonatal hyperbilirubinemia (NNH). High prevalence of Vit-B12 (65%) and folate (27%) deficiency was observed in newborns along with hyperhomocystinemia (hypHcy-25%). Preterm delivery, micronutrient deficiency, hypHcy and MTHFR 677T SNP are associated as risk factor while G allele of TCN2 C776G is protective against LBW. MTHFR 677T allele and folate deficiency are also independent risk factors for NNH.

Conclusion

We record the highest incidence of Vit-B12, folate deficiency and elevated Hcy levels, of all the studies so far reported on neonates. These together with MTHFR 677T are potential risk factors for LBW. Association of impaired folate/Hcy metabolism with NNH is reported for the first time and the possible way of interaction is discussed. It appears that proper nutritional management during pregnancy would reduce the risk of complex clinical outcomes.

Value of image-guided fine-needle aspiration cytology-a study of 500 cases

Guided Fine-Needle Aspiration Cytology (FNAC) as the first line investigation is not only useful in diagnosis of space occupying lesions but can also help in choosing appropriate management. This technique is most useful in diagnosing metastasis but is also helpful in excluding malignancy in some cases. Aim of this study is to analyze the spectrum of cytological diagnosis, adequacy, and clinicoradiological correlation of guided FNAC. The study was carried out in the departments of pathology and radiology for a period from January 2000 to November 2011. All the data were retrieved from hospital medical record section and departmental data bank and were analyzed. We have performed a total of 500 FNACs, including 234 under CT guidance and 266 under USG guidance. Among the CT-guided FNACs, 87.6% (205 cases) had adequate material which included 152 malignant cases, 38 inflammatory cases and 15 benign cases. Among the cases under USG, 91.7% (244 cases) had adequate material comprising of 112 malignant cases, 44 inflammatory cases, and 88 benign lesions. It was noted that increased number of inadequate aspirate was from lesions with smaller size and increased depth. Out of total 264 malignant cases diagnosed on FNAC, 160 cases were identified as malignant on clinical and radiological findings. Guided FNAC is useful in deep seated lesions as well as in suspicious superficial lesions and is a safe diagnostic tool. If performed properly and correlated well with clinical and radiological findings, FNAC provides correct diagnosis in most cases.

DAZL 260A > G and MTHFR 677C > T variants in sperm DNA of infertile Indian men

DAZL (deleted in azoospermia-like) 260A > G and MTHFR (methylene tetrahydrofolate reductase) 677C > T are two important autosomal variants associated with impaired spermatogenesis. In this study, we investigated DAZL 260A > G and MTHFR 677C > T variants in sperm DNA and their frequency in oligozoospermic infertile men of Indian origin. The study on sperm DNA was performed, since it is more prone to oxidative stress-induced damage and mutation. One hundred oligozoopsermic infertile men having normal chromosomal complement with intact Y chromosome and 100 age- and ethnically-matched fertile controls were investigated for these variants in their sperm genome. Spermatozoa were separated by gradient centrifugation and DNA was isolated and analyzed for the single nucleotide polymorphisms (SNPs) by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The results showed no significant differences in the frequency of DAZL AG (P = 0.58) and MTHFR CT (P = 0.44) between oligozoospermic infertile men and controls. However, 8% (8/100) oligozoospermic infertile men harbored both the variants and showed significantly (P < 0.0001) lower sperm count (3.28 +/- 1.1 vs 12.50 +/- 4.09) compared to infertile men with either of the single variant. None of the fertile controls showed the presence of the both variants. In conclusion, the combined effect of both DAZL 260A > G and MTHFR 677C > T variants may have role in compromised sperm count. However, further studies are required to find the pathological role of these combined variants in male infertility.

Evaluation of mutagenic and antimutagenic activities of neem (Azadirachta indica) seed oil in the in vitro Ames Salmonella/microsome assay and in vivo mouse bone marrow micronucleus test

AIM OF THE STUDY

The possible mutagenic and antimutagenic activity of neem oil (NO) and its DMSO extract (NDE) were, examined in the Ames Salmonella/microsome mutagenicity test and the mouse bone marrow micronucleus assay.

MATERIALS AND METHODS

Eight different strains of Salmonella typhimurium were, used to study the genotoxicity of neem oil both in the presence and absence of Aroclor-1254 induced rat liver homogenate (S9). Two-dose treatment protocol was, employed to study the cytogenetic activity in micronucleus assay. Similarly, the antimutagenic activity of neem oil and NDE was studied against mitomycin (MMC) and 7,12-dimethylbenz[a]anthracene (DMBA) in the above two test systems.

RESULTS

Neem oil was non-mutagenic in all the eight tester strains of Salmonella typhimurium both in the presence and absence of S9 mix. In the present study, there was no significant increase in the frequency of micronucleated polychromatic erythrocytes (MNPCEs) in neem oil treated groups over the negative control (DMSO) group of animals, indicating the non-clastogenic activity of neem oil in the micronucleus test. Neem oil showed good antimutagenic activity against DMBA induced mutagenicity compared to its DMSO extract. However, neem oil showed comparatively less antimutagenicity against MMC in the Ames assay. In vivo anticlastogenic assays shows that neem oil exhibited better activity against DMBA induced clastogenicity.

CONCLUSION

These results indicate non-mutagenic activity of neem oil and significant antimutagenic activity of neem oil suggesting its pharmacological importance for the prevention of cancer.

Sequence homology and structural analysis of plasmepsin 4 isolated from Indian Plasmodium vivax isolates

Plasmodium vivax malaria is a globally widespread disease responsible for 50% of human malaria cases in Central and South America, South East Asia and Indian subcontinent. The rising severity of the disease and emerging resistance of the parasite has emphasized the need for the search of novel therapeutic targets to combat P. vivax malaria. Plasmepsin 4 (PM4) a food vacuole aspartic protease is essential in parasite functions and viability such as initiating hemoglobin digestion and processing of proteins and is being looked upon as potential drug target. Although the plasmepsins of Plasmodium falciparum have been extensively studied, the plasmepsins of P. vivax are not well characterized. This is the first report detailing complete PM4 gene analysis from Indian P. vivax isolates. Blast results of sequences of P. vivax plasmepsin 4 (PvPM4) shows 100% homology among isolates of P. vivax collected from different geographical regions of India. All of the seven Indian isolates did not contain intron within the coding region. Interestingly, PvPM4 sequence analysis showed a very high degree of homology with all other sequences of Plasmodium species available in the genebank. Our results strongly suggest that PvPM4 are highly conserved except a small number of amino acid substitutions that did not modify key motifs at active site formation for the function or the structure of the enzymes. Furthermore, our study shows that PvPM4 occupies unique phylogenetic status within Plasmodium group and sufficiently differ from the most closely related human aspartic protease, cathepsin D. The analysis of 3D model of PM4 showed a typical aspartic protease structure with bi-lobed, compact and distinct peptide binding cleft in both P. vivax and P. falciparum. In order to validate appropriate use of PM4 as potential anti-malarial drug target, studies on genetic and structural variations among P. vivax plasmepsins (PvPMs) from different geographical regions are of utmost importance for drugs and vaccine designs for anti-malarial strategies.

In vitro induction of the ubiquitous 60 and 70KD heat shock proteins by pesticides monocrotophos and endosulphan in Musca domestica: potential biomarkers of toxicity

This study has investigated the effect of two highly toxic pesticides, monocrotophos (organophosphate) and endosulphan (organochlorine), on the inducibility of two major heat shock proteins, the HSP60 and HSP70, essential for cell survival, in the house fly Musca domestica. The LC50 values of the two pesticides for larva and adult (monocrotophos: 0.05 ppm for larva and 0.025 ppm for adult; endosulphan: 15 ppm for larva and 2 ppm for adult) revealed monocrotophos to be potentially more toxic than endosulphan. The relative susceptibility (lethality) of adult to either of these pesticides appeared much higher than that of larva. The expression patterns of HSP60 and HSP70 were analysed in various larval and adult tissues, exposed to varying sub-acute doses of monocrotophos (0.00010 ppm - 0.00075 ppm for larva and 0.00010 ppm - 0.00050 ppm for adult) and endosulphan (0.5ppm - 2.0ppm for larva and 0.01ppm-0.10 ppm for adult). The immunoblots revealed significant correlation between the pattern of HSP's expression and the pesticides-induced tissue injury/ mortality, visualized by trypan blue dye exclusion test. Both the pesticides caused significant induction of these HSPs in a tissue and dose—dependent manner, suggesting their importance as molecular indicators (biomarker) in the assessment of cellular toxicity caused by endosulphan and monocrotophos.

Genomic structure and sequence analysis of Lucilia cuprina HSP90 gene

The HSP90 family is one of the highly conserved chaperone families, varying between eubacteria to higher vertebrates. The HSP90 protein has been assigned different functions including thermal protection, but having major role in development. The present study is a detailed analysis of the structural characteristics of hsp90 gene (lchsp90) of sheep blowfly, Lucilia cuprina. The gene isolated by PCR revealed absence of intron. The nucleic acid and amino acid comparison revealed significant level of sequence similarity among species of various taxa. Significantly, the analysis of the amino acid sequence revealed that the HSP90 of L. cuprina belongs to hsp90β class.

Morquio Syndrome in Two Siblings: A Case Report

Morquio syndrome is a rare inherited autosomal recessive disorder characterized by the accumulation of mucopolysaccharides (glycosaminoglycans) in various body tissues. It is rare cause of dwarfism. Many pediatricians therefore are unlikely to see this case hence may miss the diagnosis due to lack of experience. With this view we report two siblings with this dwarfism highlighting the classical clinical and radiological presentation. Key words: Mucopolysaccharidosis; Morquio syndrome DOI: 10.3126/jnps.v31i1.3541J Nep Paedtr Soc 2010;31(1):68-71

Utility of serum LDH isoforms in the assessment of mycobacterium tuberculosis induced pathology in TB patients of Sahariya tribe

The present study was carried out in the Sahariya tribe of Central India, which reportedly have high prevalence of pulmonary tuberculosis. Total serum LDH and its tissue specific isoforms were estimated in TB patients and matched healthy controls to test the utility of LDH as diagnostic marker for tuberculosis. About 210 sputum positive cases and 328 age and sex matched sputum negative controls were recruited. The spectrophotometeric and densitometric analysis of each LDH isoform was carried out in both cases and controls. The mean values of serum LDH were estimated and compared for each class by t-test. The statistical comparisons were made between sputum negative controls and sputum positive cases by Mann-Whitney's U test. The spectrophotometric estimation of serum LDH revealed significant (P=0.0016) increase in its level in cases (290 IU/L) as compared to controls (248 IU/L). The densitometric analysis of individual LDH isoforms in cases and controls demonstrated significant elevation in LDH1 (P>0.05), LDH2 (P>0.05) and LDH3 (P<0.005) in sputum positive cases in comparison to sputum negative controls. Our study revealed a positive correlation between serum LDH level and the presence of mycobacteria and their load, suggesting utility of LDH as an important diagnostic marker of tuberculosis induced stress, at least in tribal areas lacking access to modern clinical tests.

In vitro induction of 60-kDa and 70-kDa heat shock proteins by endosulphan and monocrotophos in sheep blowfly Lucilia cuprina

The effect of two most commonly used and highly toxic organic pesticides, endosulphan (organochlorine) and monocrotophos (organophosphate), was studied in a blowfly, Lucilia cuprina, to test whether these pesticides induce the stress response and, if so, whether the intensity of the response, in terms of induction of heat shock proteins (HSPs), HSP60 and HSP70 in particular, is pesticide concentration dependent. The in vitro exposure of larval and adult tissues to varying concentrations of these pesticides (endosulphan: 1.0-4.0 ppm for larva and 0.05-0.50 ppm for adult; monocrotophos: 0.0005-0.0050 ppm for larva and 0.0001-0.0010 ppm for adult) revealed that both compounds were able to induce the expression of HSP60 and HSP70 proteins. Western blot analysis of these HSPs indicated that the induction of expression was tissue-specific. The trypan blue staining of pesticide-exposed tissues demonstrated monocrotophos to exert more severe effect than endosulphan, as the former compound induced both HSP60 and HSP70 significantly at a much lower concentration than that of the later. The pattern of expression of these HSPs, in general, appeared in direct correlation with the pesticide concentration. Gut tissues were found relatively more sensitive to pesticide toxicity than other tissues, as revealed by trypan blue staining, and hence, they might serve as primary targets for early detection of pesticide toxicity. The results indicated that either of these HSPs or both could serve as a potential biomarker toward assessment and monitoring of toxicity induced by these pesticides.

Need for an Individualized and Aggressive Management of Multinodular Goiters of Endemic Zones by Specially Trained Surgeons: Experience in Western Nepal

BACKGROUND

The goals of the present study were to explore the presentation of multinodular goiter (MNG) and solitary thyroid nodules (STN) in the sub-Himalayan belt, including the risk of malignancy, and to evaluate whether specialized surgeon training in endocrine surgery has an effect on reducing complications.

METHODS

This retrospective study (1998-2003) analyzed 624 patients with thyroid disorders seen in the thyroid clinic of a tertiary care hospital in western Nepal. The findings included 67.7% (n = 423: euthyroid, 297, toxic, 126) multinodular goiters (MNG) and 18.5% (n = 116) STN. Rest of patients of other thyroid disorders were excluded from the study. Ultrasonography and fine-needle aspiration cytology (FNAC) were the available diagnostic adjuncts. To evaluate the role of surgeon training, outcomes were compared between patients cared for by surgeons specially trained in endocrine surgery and those who were not. Prognostic markers indicated aggressiveness of cancers.

RESULTS

Of the 539 MNG and STN patients in this series, 236 underwent operation. Of these, 25.7% (139/539) were toxic, and 11.31% had associated carcinoma. Aggressive cancers, like poorly differentiated (4.9%) and anaplastic types (18%), were more common than in series of patients from iodine-sufficient regions. Patients 40-55 years of age were more likely to have toxicity, and those > 60 years of age were more likely to have aggressive cancers. Postoperative complication rates were lower in the group treated by surgeons who had special training in endocrine surgery.

CONCLUSIONS

There is a higher incidence of toxicity and malignancy in MNG in an endemic goiter zone. The limited diagnostic and therapeutic facilities in the region under study warrant a high degree of clinical suspicion and judgment, sound knowledge of thyroid physiology, thorough interpretation of hormone test results, and meticulous surgical techniques. The treatment must be individualized with consideration of humanitarian and socioeconomic factors, without compromising the quality of care and its long-term consequences. Aggressive management of malignancy and toxicity with total thyroidectomy is needed as primary therapy in many instances. However, subtotal excision is more useful in carefully selected cases with a small remnant. Specialized training in thyroid surgery appears to be valuable in reducing complications.

Chromosomal responses of blowfly Lucilia cuprina to heat and heavy metal stress

Chromosomal responses to heat and heavy metal shocks were studied in the pupal trichogen polytene chromosomes of Lucilia cuprina. Heat shock induced seven distinct puffs on different chromosomes at the following loci: 1C2, 21A1, 21C, 23B, 24B, 42A and 95B3. Arsenate and mercury, two of the most common toxic environmental chemical pollutants also, induced almost the same set of puffs except 20B2, which appeared to be induced by metals only and 95B3, which was not induced by arsenate. The findings suggest that a common set of gene loci encoding the heat shock proteins is responsive to these diverse environmental stresses.

Acid-base values of single pass, batch system, bicarbonate based hemodialysate

The bicarbonate, calcium, and magnesium values of a single pass, batch system, bicarbonate based hemodialysate were found to be stable during a period of 5 hours, whether the solution was extensively covered by a floating polystyrene lid or not. The pH and PCO2 of the dialysate that had been covered with a floating lid remained stable during the 5 hours, whereas the corresponding values of the dialysate that had not been so covered did show changes that were secondary to the loss of carbon dioxide. The changes were not marked enough to preclude the clinical use of the latter uncovered dialysate.

Continuous ambulatory peritoneal dialysis using self-made, ultrafiltration-sterilized, L-lactate-based dialysis solution

Continuous ambulatory peritoneal dialysis was successfully carried out in 6 end-stage renal failure patients using self-made, ultrafiltration-sterilized dialysis solutions. A Y-set was used to deliver the above solutions to sterile plastic bags.

Clinico-Radiological Spectrum of Neuronal Migrational Disorders: A Study of Paediatric Patients in the Western Region of Nepal

Objective: This study was conducted in a tertiary care paediatric hospital to ascertain the spectrum of clinical and radiological features of Neuronal Migrational Disorders in children. The role of inheritance in Neuronal Migrational Disorders is under intense investigation. Studies on Neuronal Migrational Disorders (NMDs) in children from developing countries are lacking. Method: Retrospective analysis of records of diagnosed cases by neuroimaging as Neuronal Migrational Disorders in the Department of Paediatrics. Results: Eighteen Children (2days to 8years age) with different types of neuronal migrational disorder based on neuro-imaging were included. Observed anomalies included Lissencephaly (33.3%), Pachygyria (16.6%), Polymicrogyria (5.5%), Heterotopia (11.1%), Schizencephaly (22.2%) and Hemimegalencephaly (5.5%). Focal Seizure in 5 (27.7%) cases, Generalised Tonic Clonic Seizures in 3 (16.6%) and Myoclonic Seizure in 2 (11.1%) cases were the types of seizure present in 10 (55.5%) patients. Five patients presented with Quadriparesis, two with Hemiplegia and one with Congenital Talipes Equinovarus. All the eighteen patients had some degree of Cognitive Developmental Delay. Conclusion: Lissencephaly is the most common type of Neuronal Migrational Disorder followed by Schizencepahly. Focal Seizure and Quadriparesis were the common manifestations. Family history of similar cases with parental consanguinity in Schizencephaly cases gives a clue to the autosomal recessive mode of inheritance. Family history of similar cases of Schizencephaly without any history of consanguinity indicates an autosomal pattern of inheritance. Key words: Neuronal Migrational Disorders, Lissencephaly, Schizencephaly, Cognitive Developmental Delay and Neuro-imaging.    DOI = 10.3126/jnps.v28i1.1399   J. Nepal Paediatr. Soc. Vol.28(1) p.10-13