3 research outputs found
A prospective cohort study of school-going children investigating reproductive and neurobehavioral health effects due to environmental pesticide exposure in the Western Cape, South Africa: study protocol
Abstract
Background
Research on reproductive health effects on children from low-level, long-term exposure to pesticides currently used in the agricultural industry is limited and those on neurobehavioral effects have produced conflicting evidence. We aim at investigating the association between pesticide exposure on the reproductive health and neurobehavior of children in South Africa, by including potential relevant co-exposures from the use of electronic media and maternal alcohol consumption.
Methods
The design entails a prospective cohort study with a follow-up duration of 2 years starting in 2017, including 1000 school going children between the ages of 9 to 16 years old. Children are enrolled with equal distribution in sex and residence on farms and non-farms in three different agricultural areas (mainly apple, table grapes and wheat farming systems) in the Western Cape, South Africa. The neurobehavior primary health outcome of cognitive functioning was measured through the iPad-based CAmbridge Neuropsychological Test Automated Battery (CANTAB) including domains for attention, memory, and processing speed. The reproductive health outcomes include testicular size in boys and breast size in girls assessed in a physical examination, and blood samples to detect hormone levels and anthropometric measurements. Information on pesticide exposure, co-exposures and relevant confounders are obtained through structured questionnaire interviews with the children and their guardians. Environmental occurrence of pesticides will be determined while using a structured interview with farm owners and review of spraying records and collection of passive water and air samples in all three areas. Pesticide metabolites will be analysed in urine and hair samples collected from the study subjects every 4 months starting at baseline.
Discussion
The inclusion of three different agricultural areas will yield a wide range of pesticide exposure situations. The prospective longitudinal design is a further strength of this study to evaluate the reproductive and neurobehavioural effects of different pesticides on children. This research will inform relevant policies and regulatory bodies to improve the health, safety and learning environments for children and families in agricultural settings
The inhibitory effect of rooibos on cytochromes P450 and downstream in vitro modulation of steroid hormones
Thesis (MSc)--Stellenbosch University, 2015.ENGLISH ABSTRACT: This study describes:
1. Substrate binding assays investigating the effects of methanolic extracts of
unfermented and fermented Rooibos on the binding of natural substrates to ovine
adrenal microsomal and mitochondrial P450 enzymes, demonstrating the interference
of substrate binding in the presence of the Rooibos extracts.
2. The effects of selected flavonoids (quercetin, rutin and aspalathin) on the binding of
natural substrates to ovine adrenal microsomal and mitochondrial P450 enzymes,
demonstrating interference of substrate binding in the presence of the flavonoid
compounds.
3. Substrate conversion assays in non-steroidogenic COS-1 cells to investigate the
effects of methanolic extracts of unfermented and fermented Rooibos on the activity
of key steroidogenic P450 enzymes (CYP17A1, CYP21A2, CYP11B1, and
CYP11B2), demonstrating inhibition of the catalytic activity in the presence of
Rooibos extracts.
4. The effects of selected flavonoids on the substrate conversion of the aforementioned
key steroidogenic enzymes expressed in COS-1 cells.
5. An investigation of the effect of methanolic extracts of unfermented and fermented
Rooibos on steroid hormone production in human adrenal H295R cells under basal
and stimulated conditions, demonstrating the modulating effects of unfermented and
fermented Rooibos extracts. Basal and stimulated steroid hormone production was
decreased in the presence of unfermented and fermented Rooibos.AFRIKAANSE OPSOMMING: Hierdie studie beskryf:
1. Die gebruik van substraatbindings-essais om die effek van metanoliese ekstrakte, van
gefermenteerde- en ongefermenteerde Rooibos, op die binding van die natuurlike
substrate aan skaap adrenale mikrosomale en -mitochondriale P450 ensieme te bepaal.
Daar is getoon dat die ekstrakte 'n beduidende inhiberende effek op ensiemsubstraatinteraksie
gehad het.
2. Die die inhiberende effek van geselekteerde flavonoïede (kwersetien, rutien and
aspalatien) op die binding van die natuurlike substrate aan skaap adrenale
mikrosomale en -mitochondriale P450 ensieme.
3. Die gebruik van substraatomsettings-essais in nie-steroïedogeniese COS-1 selle, om
die effek van gefermenteerde- en ongefermenteerde Rooibos ekstrakte op die
aktiwiteit van die steroïedogeniese P450 ensieme (CYP17A1, CYP21A2, CYP11B1,
and CYP11B2) se katalitiese aktiwiteit te bepaal. Daar kon aangetoon word dat die
katalitise aktiwiteite van bg. ensieme beduidend beïnvloed word deur die Rooibos
ekstrakte.
4. Die gebruik van substraatomsettings-essais in nie-steroïedogeniese COS-1 selle, om
die effek van geselekteerde flavonoïede op die aktiwiteit van bogenoemde
steroïedogeniese P450 ensieme te bepaal.
5. 'n Ondersoek na die invloed van metanoliese ekstrakte van gefermenteerde- en
ongefermenteerde Rooibos op steroïedhormoon biosintese in die menslike adrenale
H295R-selmodel. Die ondersoek, onder basale en gestimuleerde toestande, het getoon
dat beide Rooibosekstrakte in bogenoemde toestande steroïedhormoon produksie
geinhibeer het