Chemical carcinogenesis and chemoprevention: Scientific priority area in rapidly industrializing developing countries

Occupational cancers are now a serious concern in industrializing developing countries where exposure levels to hazardous chemicals considerably exceed regulatory limits established in industrialized countries. The association between increasing use of chemicals and associated disorders and chemoprevention or anticarcinogenesis is insufficiently recognized in these countries. The eradication of chemicals would assist in cancer prevention. This is however, not pragmatic, thus the need to seek alternative means of cancer prevention. Cancer chemoprevention or anticarcinogenesis is the process of exposure of an animal including humans to a substance that will reduce the incidence of cancer that would otherwise develop. Lack of knowledge of the multiple pathways by which chemically induced cancer may arise has led to the erroneous view for a long time that the study of chemoprevention was academic. While this field is gaining an increasing and sustained attention in the developed countries it has received little attention in the industrializing developing countries where the incidence of cancers appears to parallel the pace of industrialization. Sub-optimal intake of specific micronutrients so common in developing countries may contribute to greater susceptibility to cancer. Micronutrient deficiency disorders (MDDs) is considered orders of magnitude more important than radiation because of constancy of exposure to a milieu promoting DNA damage. Zinc (Zn) for instance is an antioxidant, a component of p53 and a critical factor in gene expression. Poor Zn nutrition may be an important risk factor in oxidant release and development of DNA damage and cancer. A deficiency of Zn ranks among the top ten leading causes of death in developing countries. As chemo preventive agents are present in natural human foods abundant in developing countries, this should be one of the highest research priorities of the rapidly industrializing developing countries.Key words: Chemical carcinogenesis, chemoprevention, DNA damage, oxidative stress, Industrialization, p53protein, mutation

The effect of demographic variables on the prevention of HIV/AIDS infection among public secondary school students in Abuja

Objectives: HIV/AIDS remains a growing public health concern worldwide. Nigeria has been rated second largest HIV epidemic country in the world, of which 60% is among young people. Adolescents' risky behavior increases their vulnerability to HIV and AIDS and they cannot appreciate the adverse consequences of their actions. They have inherent characteristics among which are demographic variables that affect their ability to prevent HIV/AIDS infection. Thus, the study examined the effect of their demographic variables on preventing HIV/AIDS infection so as to adequately report them and proffer solutions targeted at reducing the disease spread.Methods: A descriptive survey was used for the study. Multistage sampling technique used to select 602 secondary school students that participated in the study. Self-developed validated questionnaire used to collect data. Data analyzed using SPSS 20; descriptive statistics of frequency counts, means, and percentages were used; Inferential statistics of ANOVA, t-test and regression used to test hypotheses set at 0.05 significant level.Results: Students above 18 years markedly displayed awareness of preventive measures of HIV/AIDS (p < 0.05); religion and the class of the students had significant effect on their preventive measures of HIV/AIDS; gender significantly affected peer pressure and the students' risky behaviour. (P < 0.05); females are more at risk.Conclusion: Demographic variables (age, religion, class and gender) still affect students' ability to prevent HIV/AIDS infection. Efforts must be made by stakeholders preventing HIV/AIDs to put them under check through proactive counseling and sexuality education.Keywords: Preventive measures, HIV/AIDS infection, Secondary schools, demographic variables, Abuj

High cadmium / zinc ratio in cigarette smokers: potential implications as a biomarker of risk of prostate cancer.

Tobacco smoke may be one of the most common sources of cadmium (Cd) in the general population, particularly in the rising population of smokers in developing countries. Although a relationship between bothcigarette smoking and environmental Cd contamination with prostate cancer exist, the mechanisms are unclear. Most prospective cohort studies found a positive association between current smoking and a fatal cancer of the prostate. We investigated the interaction between zinc and cadmium and the potential risk of prostate cancer insmokers. Serum cadmium level was significantly (

Relationship between Thyroid Autoantibodies, Imbalance of Some Essential Trace Elements in the Pathology of Simple Nontoxic Goitre

Autoimmunity and certain micronutrients have been implicated in the pathogenesis of thyroid disorders such as simple nontoxic goitre (SNTG). Alterations in certain trace elements and autoimmune parameters may arise from an indeterminate autoimmune mechanism. We sought to evaluate the association and interactions between trace elements and autoantibodies in simple nontoxic goitre. All consenting participants based on clinical and thyroid function tests were recruited for this case-control study. Subjects comprised of 37 patients and 44 controls, from the Surgery Outpatient and Endocrinology Clinics of the University College Hospital and the Lagos University Teaching Hospital, respectively. Anthropometric indices were measured, serum trace element were determined using atomic absorption spectrophotometer (AAS), thyroid autoantibodies and thyroid function tests were performed in serum using Enzyme linked immunosorbent assay (ELISA). Thyroperoxidase and thyroglobulin antibodies were significantly elevated in SNTG compared with controls, suggesting immune alteration. The free triiodothyronine (FT3) and free thyroxine (FT4) were significantly increased in SNTG (3.72±0.02 and 14.9±0.21 pmol/L) compared with controls (3.63±0.12. pmol/L and 13.12±0.12 pmol/L). The level of TSH was significantly increased in SNTG compared with controls. Antithyroglobulin level was positive in 14.0% (130.93±35.02 kiu/L) SNTG. Significantly reduced levels of Cu (11.92±0.32, µmol/L), Fe (20.13±0.52µmol/L) and Se (0.53±0.01µmol/L) relative to the controls (16.12±0.22, 28.73±0.23 and 3.82±0.03µmol/l) were found in SNTG. Simple nontoxic goitre appear to be associated with imbalance in certain essential trace elements and presence of autoantibodies which probably are among the key mechanisms involved in the pathology of thyroid disorders. Early detection of these abnormalities may be useful in the better understanding and improved management of thyroid disorders. Keywords: Autoimmunity, trace elements, Iodine, nontoxic goitre, thyroid peroxidas

Serum uric acid and standardized urinary protein: reliable biondicators of lead nephropathy in nigerian lead workers

The question as to whether lead causes renal damage still remains largely controversial. Eighty-five male lead workers and 51 control subjects who had never been occupationally exposed to lead were studied. They were also classified according to duration of exposure. The mean age of the lead workers was similar to that of control subjects. The mean duration of occupational exposure to lead was 16.7 ± 2.13 years. Blood lead level was significantly higher in Pb workers than in controls (P 0. 05). Serum uric acid level was significantly raised in lead workers than in controls (P<0. 001). In addition it was significantly correlated with blood lead level (r = 0.24, P < 0.0026). Standardized total urinary protein was also significantly raised in lead workers compared with control (P < 0. 001). Serum potassium level was equally significantly higher in lead workers than in controls (P < 0.01). In contrast serum total calcium level was significantly decreased in lead workers than in controls (P < 0.01), while serum phosphate level did not differ significantly. Serum uric acid level and standardized urinary protein determination may prove a readily available, reliable marker of lead nephropathy in Nigerians

Evaluation of heavy metal levels in serum of Wistar rats exposed to engine oil

Purpose: Data are available that indicate there is an elaborate elemental constitution of petroleum products, with identified elements contained in the many products being additive (e.g. Ca, Zn and P) as well as wear metals (e.g. Ag, Al, Ba, Cd, Cr, Cu, Fe, Mg, Mo, Na, Ni, Pb and Sn). In addition, incessant deliberate exposure of engine oil to both human beings and farm animals for therapeutic reason has been reported. Therefore the objective of this study is to evaluate the levels of heavy metals in serum of engine oil-exposed rats. Materials & Methods: Thirty adult female rats were divided equally into 5 groups. The first and second groups were treated with engine oil by oral route (as contaminant of feed) at dosage levels of 0.5 and 1.0 mL/kg body weight respectively. The third and forth groups received the test agent through the dermal route at dosage levels of 0.5 and 1.0 mL/kg body weight while the fifth group served as the control. The duration of the study was 30 days, after which blood was obtained from each rat, centrifuged and the resultant serum used for the analysis of heavy metals by employing Atomic Absorption Spectrometry (AAS). Data were analyzed using analysis of variance (ANOVA), p≤0.05 was considered significant. Results: Data obtained showed that there were significant differences in the levels of aluminium, silicon, cadmium, lead, arsenic, vanadium, and nickel. Conclusions: These increases suggest that incessant exposure to engine oil may be dangerous and therefore constitute health hazard

Antioxidant Micronutrients as Intersectoral Link between Health and Agriculture

Environmental and ecological disorders and the attendant health problems especially cancer and heart diseases are a major concern currently. Although cancer is perhaps the most feared and best known of the chronic pathologic effects of environmental pollution, it should be recognized that environmental agents especially heavy metals, such as lead and cadmium, may also cause behavioural abnormality which can lead to increase in crime rate. Antioxidant micronutrients are protective against these dreaded disorders. Environmental problems extend beyond the boundaries of the traditional confines of the health sector. It also affects the agricultural sector and this sector may also have an ameliorative influence on the degree of environmental and ecological disorders. This report emphases the need for the two major sectors, health and agriculture to evolve ways of checking the deleterious effects. Increase consumption of antioxidant micronutrients available in fruit and vegetables namely vitamins A, B, C, and E, β-carotene and selenium should be consistently recommended by the health sector to reduce the toxic effects of environmental pollutants. This report draws attention to environmental and ecological disorders and emphasizes the needs not to treat them in isolation but that they are inseparable. These disorders will be examined in conceptual and programmatic terms. Intersectoral collaboration between the agricultural and health sectors appears desirable by helping to prevent disease, promoting health and improving the quality of life by means of antioxidant micronutrients. The role of the agricultural sector in this regard should be to increase the production of these crops to make them readily available at low cost in Nigeria. This intersectoral collaboration is required for sustainable development of which health should be a goal

Serum levels of minerals and vitamins in two categories of female alopecia subjects using hair relaxer

Background: In an earlier study, we identified an association between hair relaxer-induced alopecia and decreased zinc levels. This study hopes to identify if age at first exposure to hair relaxer plays a role in the development of alopecia in the small percentage of women of African descent who use hair-relaxing products for hair-straightening purposes and develop lingering, nonresolving alopecia. Methods: Two categories of subjects were recruited for the study. These groups—Group A and Group B—commenced use of hair relaxer in the second and third or fourth decade of life, respectively. Group C which served as the control group consisted of women who had used relaxer but did not manifest alopecia. Renal and hepatic indices as well as micronutrient levels were estimated in serum samples taken from these subjects. Data obtained were subjected to statistical analysis using Student t test, analysis of variance, and Pearson correlation coefficient. Results: Of all the micronutrients, only zinc level was significantly decreased in the two categories of alopecia subjects compared with controls, and when the zinc levels of the two groups were compared, they were not significantly different. Age in association with an alteration in serum zinc status seemed to have played an independent or combined role as an etiologic factor in hair relaxer-induced alopecia in Group B subjects, as a positive correlation (r = 0.631; p = 0.012) was observed between age and duration of alopecia; alopecia also commenced much earlier in the course of hair relaxer application in Group B compared with Group A. Conclusion: This is probably an indication that early exposure may confer some forms of protection even in zinc-deficient individuals. Moreover, an assessment of serum zinc level in users of hair relaxer may be encouraged even before initial contact with this agent, such that women at risk could be advised to take zinc supplements

Molecular epidemology: a better approach for the early detection of pathophysiologic response to environmental toxicants and disease

Our environment is becoming increasingly contaminated by a profusion of substances in the form of industrial and Municipal Waste, air and water pollutants; by heavy metals (such as lead) herbicides, pesticides, cosmetics and so on. The number of chemicals that affect man increases at alarming rates. These agents may be dangerous because they produce biochemical, genetic, structural or physiological lesions in a significant segment of the population. The importance of elucidating the nature and the mechanisms of physiological and toxicological reactions has been emphasized in the investigations of occupational and environmental diseases, such investigations have revealed that the clinical manifestations of intoxication may have their origin in injurious effects of subcellular or biochemical types. Slight to moderate derangements in metabolism may impair the functional activity of organs and lead to subclinical or overt clinical effects. These may elude detection or recognition of their health implications unless biomarkers, the functional components of molecular epidemiology are employed. Molecular epidemiology is an approach which aims to examine aetiology of disease in a more precise way by focusing on biomarkers of disease risk rather than relying on the actual occurrence of disease. Such studies can be carried out in a short time and with relatively small numbers of subjects compared with conventional epidemiology, which though currently more popular merely reveals association, and causal links often remain obscure. Detection of early biochemical lesions that are related to subsequent changes in structure and physiology would be useful as early indicators of environmental hazards that produce disease in humans, that is by employing molecular epidemiology. This will be greatly enhanced by newer tools, such as toxicogenomics and metabonomics

Molecular epidemology: a better approach for the early detection of pathophysiologic response to environmental toxicants and disease

Our environment is becoming increasingly contaminated by a profusion of substances in the form of industrial and Municipal Waste, air and water pollutants; by heavy metals (such as lead) herbicides, pesticides, cosmetics and so on. The number of chemicals that affect man increases at alarming rates. These agents may be dangerous because they produce biochemical, genetic, structural or physiological lesions in a significant segment of the population. The importance of elucidating the nature and the mechanisms of physiological and toxicological reactions has been emphasized in the investigations of occupational and environmental diseases, such investigations have revealed that the clinical manifestations of intoxication may have their origin in injurious effects of subcellular or biochemical types. Slight to moderate derangements in metabolism may impair the functional activity of organs and lead to subclinical or overt clinical effects. These may elude detection or recognition of their health implications unless biomarkers, the functional components of molecular epidemiology are employed. Molecular epidemiology is an approach which aims to examine aetiology of disease in a more precise way by focusing on biomarkers of disease risk rather than relying on the actual occurrence of disease. Such studies can be carried out in a short time and with relatively small numbers of subjects compared with conventional epidemiology, which though currently more popular merely reveals association, and causal links often remain obscure. Detection of early biochemical lesions that are related to subsequent changes in structure and physiology would be useful as early indicators of environmental hazards that produce disease in humans, that is by employing molecular epidemiology. This will be greatly enhanced by newer tools, such as toxicogenomics and metabonomics