Ecotoxicology of arsenic in the hydrosphere: Implications for public health

Arsenic is a naturally occurring metalloid element that is found in soil, air and water. Environmental arsenic exists in both organic and inorganic states. Organic arsenicals are generally considered nontoxic, whereas inorganic forms are toxic. The most acutely toxic form is arsine gas. Inorganic arsenic exists predominantly in trivalent (As3+) and pentavalent (As5+) forms, where trivalent compounds aremore toxic than pentavalent ones. Human activities have also intensified arsenic accumulation in the environment. Organs most susceptible to arsenic toxicity are those involved with absorption,accumulation or excretion, including the skin, circulatory system, gastrointestinal tract, liver and kidney. Arsenic is associated with multiple health effects, including Blackfoot diseases, diabetes,hypertension, peripheral neuropathy and multiple vascular diseases. Other effects include anemia, liver damage, portal cirrhosis, hematopoietic depression, anhydremia, sensory disturbance and weight loss. In addition to acute toxicity, long-term exposure to inorganic arsenic is associated with certain forms of cancer of the skin, lung, colon, bladder, liver and breast. Understanding the ecotoxicological effects of arsenic in the environment is paramount to mitigating its deleterious effects on ecological and human health. This paper is therefore a review of the ecotoxicological effects of arsenic on human and ecological health

Some haematological profiles of children with malaria parasitaemia in Port Harcourt, Nigeria

Some haematological profiles of children with malaria parasitaemia in Port Harcourt was studied with the concent of the hospital management. The study-area was zoned into A, B, and C, for convenience. Three hundred and fifty-two subjects age

Parametric sensitivity analysis of a mathematical model of HIV infection of CD4+ T-Cells

Background: In this complex mathematical model of a system of continuous nonlinear first order ordinary differential equations of HIV infection of CD4+ T-Cells, the scientific problem of determining the sensitivity of model parameters, s and a over the model parameter d is yet to be tackled.Aim: To determine the sensitivity of model parameters , s and a over the model parameter d by using the one-at-a-time type of sensitivity analysis over a chosen time range.Methods:  In this  bio-medical study, we used the tool of a sensitivity analysis to select the most sensitive model parameters of this multi-parameter system. This method is based on a variation of a model parameter one-at-a-time when other model parameters are fixed.Results: We have found that the maximum proliferation rate'a' of target cells, the T population density 'Tmax' at which proliferation shuts off and the rate's' at which new T cells are created from sources within the body such as thymus are selected using the three  mathematical norms of 1-norm, 2-norm and infinity norm as the most sensitive parameters while the death rate'd' of the T cells is selected as the least sensitive.Conclusion: The implications of these contributions for further data validation, parameter estimation and HIV mitigation policy in a Nigerian population are suggested. The details of the sensitivity properties of other model parameters will be the subject of a future publication.Keywords:  parametric,  Sensitivity analysis, Mathematical model, HIV/AIDS model, Policy implications, T cell