Free radicals or reactive oxygen species (ROS) generated from various sources in the environment as well as from cellular processes in the body are of serious health challenges. Overwhelming levels of these free radicals disrupt the antioxidant defense system in the body thereby damaging cell membranes and cellular macromolecules such as proteins, lipids and nucleic acids leading to cell death or causing mutations leading to uncontrolled cell division. Once the cellular antioxidant system is disrupted and becomes deficient, oxidative stress emerges thereby promoting several diseases such as diabetes, arthrosclerosis, cancer, cardiovascular diseases, etc. Better management of oxidative stress requires antioxidants from external sources to supplement the body's antioxidant defense system. Because of their natural origin and therapeutic benefits, plants have been considered as a major source of antioxidants. Certain non-enzymatic plant phytochemicals such as glutathione, polyphenols, bioflavonoids, carotenoids, hydroxycinnamates as well as some vitamins have shown to possess antioxidant properties in vitro and in vivo. These plant phytochemicals are now been used in the prevention and management of oxidative stress-related diseases.

Several heavy metals are found naturally in the earth crust and are exploited for various industrial and economic purposes. Among these heavy metals, a few have direct or indirect impact on the human body. Some of these heavy metals such as copper, cobalt, iron, nickel, magnesium, molybdenum, chromium, selenium, manganese and zinc have functional roles which are essential for various diverse physiological and biochemical activities in the body. However, some of these heavy metals in high doses can be harmful to the body while others such as cadmium, mercury, lead, chromium, silver, and arsenic in minute quantities have delirious effects in the body causing acute and chronic toxicities in humans. The focus of this chapter is to describe the various mechanism of intoxication of some selected heavy metals in humans along with their health effects. Therefore it aims to highlight on biochemical mechanisms of heavy metal intoxication which involves binding to proteins and enzymes, altering their activity and causing damage. More so, the mechanism by which heavy metals cause neurotoxicity, generate free radical which promotes oxidative stress damaging lipids, proteins and DNA molecules and how these free radicals propagate carcinogenesis are discussed. Alongside these mechanisms, the noxious health effects of these heavy metals are discussed.

BackgroundThe association between ABCC8 gene C49620T polymorphism and type 2 diabetes (T2D) in populations of diverse ethnic backgrounds has been reported. However, such occurrence in an African population is yet to be established. This case-control study involving 73 T2D and 75 non-diabetic (ND) patients investigated the occurrence of this polymorphism among T2D patients in Nigeria and assessed its relationship with body lipids of patients.MethodsDemographic and clinical characteristics of patients were collected and lipid profile indices including total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL) and high density lipoprotein (HDL) were assayed. Restriction fragment length polymorphism-PCR (RFLP-PCR) was employed to genotype the ABCC8-C49620T polymorphism using PstI restriction enzyme.ResultsThis study revealed significantly (p < 0.05) higher prevalence of the T allele of the ABCC8 gene in T2D patients (33.1%) compared to ND patients (28.0%). The mutant TT genotype was also higher than the CC and CT genotypes in T2D patients compared to ND patients but did not show any significant risk (p>0.05) of T2D for the unadjusted codominant, dominant and recessive models. Following age adjustment, the mutant genotypes (CT and TT) showed significant (p<0.05) risk of T2D for all the models with the recessive model presenting the greatest risk of T2D (OR: 2.39, 95% CI: 1.16-4.91, p<0.018). The TT genotype significantly (p<0.05) associated with high level of HDL and reduced levels of TC, TG and LDL in non-diabetic patients but was not associated with any of the demographic and clinical characteristics among T2D patients.ConclusionsABCC8 C49620T polymorphism showed possible association with T2D marked by predominance of the mutant TT genotype in T2D patients. However, the relationship between TT genotype and lipid abnormalities for possible beneficial effect on people suffering from T2D is unclear.

ObjectivesPrevalence of child and adolescents’ overweight and obesity in low- and middle-income countries has increased dramatically. Simultaneously, the incidence of pre-hypertension/hypertension is also increasing in children, which, in turn, predisposes these children to the risk of cardiovascular disease (CVD) in later life. The present study assessed cardiometabolic risk factors and early indicators of vascular dysfunction in adolescents from a low socio-economic rural area in South Africa.DesignCross-sectional cohort study.SettingThe study was conducted in public schools in Mthatha, OR Tambo district municipality, Eastern Cape Province, South Africa.ParticipantsA total of 244 adolescents (188 females) of African ancestry aged 13–16 years were enrolled.Primary and secondary outcome measuresAnthropometric and haemodynamic measures and pulse wave velocity (PWV) were related to overweight/obesity and hypertension. Blood markers of cardiometabolic syndrome were assessed as well as vascular function (via PWV).ResultsOne-third (33.0%) of the adolescents exceeded the age and sex-specific body mass index percentiles for overweight (≥85th) or obesity (>95th) with a prevalence of 61.1% pre-hypertensives in this group. Overweight/obesity and hypertension were associated with higher triglycerides (lean:overweight: 0.79<1.01 mmol/L; normotensive:hypertensive: 0.82<0.89 mmol/L). Fasting glucose was higher in hypertensive as compared to normotensive adolescents (4.85>4.69 mmol/L, p<0.05). PWV was elevated in 25.9% of the children and significantly correlated with asymmetric dimethylarginine and systolic blood pressure (p<0.001).ConclusionOverweight/obesity and hypertension show a high prevalence in rural South African youth. Almost half of the studied adolescents are at risk for developing CVD. The high association between cardiometabolic risk factors and PWV further suggests that hypertension in adolescents may promote the progression of CVD in adulthood. Early detection of those at risk and the implementation of preventive strategies in underprivileged young people is urgently needed to stop the progression of vascular damage and manifestation of CVD in rural African children.

Cardiovascular disease (CVD) risk factors are known to begin early in life, but limited data on the relationship of obesity and hypertension with other known CVD risk factors, such as endothelial dysfunction, oxidative stress, and chronic low-grade inflammation is available on children. In this cross-sectional study involving 6–9 years old school children aged from the Eastern Cape Province of South Africa the relationship between obesity/hypertension and other risk factors for CVDs was investigated. General anthropometric parameters were measured, followed by blood pressure (BP) measurements and pulse wave velocity (PWV). Urine samples were collected for the determination of albumin, creatinine, asymmetric dimethylarginine (ADMA), 8-hydroxy-2deoxyguanosine (8-OHdG), and thiobarbituric acid-reactive substance (TBARS). Overweight/obesity (19.28%) and pre-hypertension/hypertension (42.16%) were prevalent in children. Mid-upper arm circumference (MUAC), a marker of obesity, was positively correlated with ADMA, while ADMA and PWV were significantly different (p < 0.05) between hypertensive and normotensive children. Also, TBARS and 8-OHdG were significantly (p < 0.05) increased in hypertensive subjects. Creatinine was significantly (p < 0.05) increased in obese, as well as in hypertensive children, and positively associated with waist circumference (WC) and neck circumference (NC). In conclusion, obesity and hypertension were associated with renal-cardiovascular disease risk, while oxidative stress showed a possible association with obesity in 6 to 9 year old South African children of African descent. This suggests that South African children of African descent may be becoming more prone to developing CVDs, and therefore may require early intervention for the prevention of CVDs in the near future.

Background:Though measures are being put in place for the management of Hepatitis B virus (HBV) infection in Nigeria, children remain the most vulnerable to develop chronic hepatitis. Routine screening in children is therefore necessary for effective control. However, the performance of the commonly used immunochromatographic test (ICT) strips has been challenging. Also, identifying the risk factors of transmission in this age group is of importance for the implementation of preventive measures. Hence, the goal of this study was to assess the test performance of the routinely used ICT strip and identify the associated clinical manifestations and risk factors of HBV.Methods:A cross sectional study involving 270 children below six years of age was conducted at ESUTH and Favor Child Pediatrics Hospital in Enugu, Nigeria. The subjects were screened for HBV by ICT and ELISA assays and a structured questionnaire was used to obtain participants data including demographic, socioeconomic, signs and symptoms, risk factors and vaccination.Results:BBased on ELISA, 31 out of 270 children were positive for HBV with an infection rate of 11.5%. ICT kit showed a low sensitivity of 51.6% in diagnosing HBV but was highly specific (100%) and accurate (94.4%). HBV infection was not associated with sex (χ2: 0.209; p = 0.401). The prevalence of HBV infection was similar in all the age group and HBV infection was not associated (χ2: 2.099; p = 0.914) with age group. All the clinical manifestations were not associated (p > 0.05) with HBV infection. Blood transfusion, shared items, tattoo marks and history of surgery associated significantly (p < 0.05) with HBV infections having odd ratios of 4.247, 4.224, 3.134 and 3.195 respectively. The vaccination rate was 55.2% (159/270) and only 3 (1.1%) out of 159 vaccinated subjected contracted the infection (OR: 0.068, p < 0.0001).Conclusions:HBV was prevalent (11.5%) in children below six years old in Enugu metropolis. Moreover, the routinely used ICT test was less reliable than ELISA in diagnosis HBV infection. More so, shared items, blood transfusion, tattooing and history of surgery were potential risk factors while vaccination served as a protective factor against the infection.

Vascular dysfunction is known to be an initiator of the development and progression of cardiovascular diseases (CVDs). However, there is paucity of information on the relationship of vascular dysfunction with cardiovascular risk factors in children of African ancestry. This study investigated the relationship between cardiovascular risk factors and vascular function in South African children of African ancestry. A cross-sectional study on 6–9-year-old children in randomly selected rural and urban schools of the Eastern Cape Province of South Africa was conducted. General anthropometric indices were measured, followed by blood pressure (BP) measurements. The pulse wave velocity (PWV) was measured using a Vicorder. Albumin to creatinine ratio (ACR), asymmetric dimethylarginine (ADMA), 8-hydroxy-2deoxyguanosine (8-OHdG) and thiobarbituric acid reactive substance (TBARS) were assayed in urine. Children from urban settings (10.8%) had a higher prevalence of overweight/obesity than their rural counterparts (8.5%) while the prevalence of elevated/high blood pressure was higher in rural (23.2%) than urban children (19.0%). Mean arterial blood pressure (MAP) and diastolic blood pressure (DBP) increased with increasing PWV (p < 0.05). Body mass index (BMI), diastolic blood pressure (DBP) and mean arterial blood pressure (MAP) positively associated (p < 0.05) with PWV. Creatinine, albumin and ACR significantly (p < 0.005) increased with increasing ADMA. ADMA associated positively (p < 0.05) with creatinine and 8-OHdG. In conclusion, vascular dysfunction was associated with obesity, high blood pressure, oxidative stress and microalbuminuria in South African children of African ancestry.

Though the association between high blood pressure and microalbuminuria is well established in adults, there is a paucity of information on microalbuminuria in children. This study investigated the relationship between high blood pressure and microalbuminuria in 6–9-year-old children. A cross-sectional study, which included 306 primary school children of age 6–9 years old from urban areas (n = 154) and rural areas (n = 152) of the Eastern Cape Province of South Africa, was conducted. Participants’ anthropometric data were determined and systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured and converted to BP percentiles for age, sex and height. Creatinine and albumin concentrations were assayed in early morning midstream urine and the albumin to creatinine ratio (ACR) was calculated. There was a 42.8% prevalence of elevated blood pressure/high blood pressure (E-BP/H-BP) and a 10.1% prevalence of microalbuminuria. Among the 131 children with E-BP/H-BP, 17 had elevated ACR with a prevalence of 13.95%. SBP and HR increased with increasing range of ACR and, furthermore, SBP was significantly (p < 0.05) higher in children with moderately and severely increased ACR. SBP was associated with ACR and increased SBP predicted microalbuminuria (R2 = 0.42, adj R2 = 0.039, B: 0.120, p = < 0.05). In conclusion, microalbuminuria was present in 6–9-year-old South African children of African Ancestry and a weak association was observed with SBP in children.