Browsing by Author "Tang, L."
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Item Aflatoxin–albumin adducts and correlation with decreased serum levels of vitamins A and E in an adult ghanaian population(Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment, 2009-01) Tang, L.; Xu, L.; Afriyie-Gyawu, E.; Liu, W.; Wang, P.; Tang, Y.; Wang, Z.; Ankrah, N.A.; Huebner, H.J.; Ofori-Adjei, D.et.alA study of aflatoxin (AF) exposure and the levels of vitamins A and E was carried out with a group of 507 Ghanaian participants. AFB1–albumin adducts (AFB-AA) were measured by radioimmunoassay and vitamins A and E were measured by high-performance liquid chromatography (HPLC). The average level of serum AFB-AA was 0.94 ± 0.64 (range = 0.1–4.44) pmol mg−1 albumin. Mean levels of vitamins A and E were 1.32 ± 0.48 (range = 0.41–4.85) µmol l−1 and 15.68 ± 4.12 (range = 6.35–30.40) µmol l−1, respectively. A significantly negative correlation was found between serum AFB-AA and vitamin A levels (r = −0.110, p = 0.013). An even stronger, significant negative, correlation was found between serum AFB-AA and vitamin E levels (r = −0.149, p < 0.001). Serum AFB-AA levels were statistically higher (median = 0.985 pmol mg−1 albumin) in subjects who had low levels of both vitamins A and E as compared with the levels (median = 0.741 pmol mg−1 albumin) subjects who had high vitamins A and E levels (p trend = 0.001). To verify these findings, blood samples were again collected from 165 of the 507 people 3 months after the initial collection. Significantly negative correlations were confirmed between levels of serum AFB-AA and both vitamins A (r = −0.232, p = 0.003) and E (r = −0.178, p = 0.023). Again, high serum AFB-AA concentrations (median = 1.578 pmol mg−1 albumin) were found in subjects with low levels of vitamins A and E compared with the concentrations (median = 1.381 pmol mg−1 albumin) in subjects with high levels of vitamins A and E (p trend = 0.002). These data show that AF exposure was associated with decreased levels of serum vitamins A and E in high-risk human populations, which may significantly influence the incidence of AF-related adverse health effects. © 2009 Taylor & Francis Group, LLC.Item NovaSil clay does not affect the concentrations of vitamins A and E and nutrient minerals in serum samples from Ghanaians at high risk for aflatoxicosis(Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment, 2008-08) Afriyie-Gyawu, E.; Wang, Z.; Ankrah, N.A.; Xu, L.; Johnson, N.M.; Tang, L.; Guan, H.et.al.To assess the potential interference of NovaSil (NS) clay with micronutrients in humans, vitamins A and E and minerals (15 nutrient and 15 non-nutrient minerals) were measured in serum samples from a 3-month intervention trial with NS. Participants (n = 177) were randomly divided into three groups that received 3.0 g NS day−1 (high dose, HD), 1.5 g NS day−1 (low dose, LD), or placebo (PL). Levels of vitamins A and E in serum were comparable among the three study groups at baseline, 1 month and 3 months of NS intervention. Gender-stratified non-parametric mixed-effect model analysis showed no significant effects of dose and dose–time interaction for levels of vitamins A and E. A significant time effect was detected; however, it was limited to an increase in vitamin E in the male participants over the course of the study. No significant differences were found in levels of the nutrient and non-nutrient minerals between the HD and PL groups at baseline and 3 months of NS intervention, except for strontium levels. Strontium was significantly increased (p < 0.001) in the HD group (male = 113.65 ± 28.00 µg l−1; female = 116.40 ± 24.26 µg l−1) compared with the PL group (male = 83.55 ± 39.90 µg l−1; female = 90.47 ± 25.68 µg l−1) following the 3-month intervention with NS. These results, combined with safety and efficacy data, confirm that NS clay is highly effective in reducing aflatoxin exposure and acts as a selective enterosorbent that does not affect the serum concentrations of important vitamins and nutrient minerals in humans. © 2008 Taylor & Francis Group, LLC.Item NovaSil clay intervention in Ghanaians at high risk for aflatoxicosis. I. Study design and clinical outcomes(Food Additives and Contaminants 25(1):76-87, 2008) Afriyie-Gyawu, E.; Ankrah, N. A.; Huebner, H.J.; Ofosuhene, M.; Kumi, J.; Johnson, N.M.; Tang, L.; Xu, L.; Jolly, P.E.; Ellis, W.O.; Ofori-Adjei, D.; Williams, J.H.; Wang, J.S.; Phillips, T.D.In a phase I clinical trial in the U.S., NovaSil clay (NS) showed no significant adverse health effects in humans. In this study (3 month duration), a double-blinded, placebo controlled clinical trial was conducted in Ghana to investigate the safety, tolerance, and aflatoxin sorption efficacy of dietary NS. Volunteers (507 subjects, ages from 18 – 58 yrs) were clinically screened to evaluate their general health, pregnancy status, and levels of blood AFB1-Albumin adducts. Of these subjects, 177 (101 males, 76 females) were randomly assigned to 3 groups: high-dose (HD), low-dose (LD) and placebo-control (PL) groups receiving 3.0, 1.5 and 0 g NS/day in capsules. As a safety precaution, 3.0 g NS was selected as the highest dose since it represented the MED (minimal effective dose) of NS for AFs based on previous animal studies. NS capsules were administered to each participant under the supervision of trained study monitors prior to meals. Blood and urine samples were collected for laboratory analysis. Physical examinations were performed monthly and follow-up was taken to record any side effects daily. Ninety-four percent of the participants (166 of 177) completed the study and compliance rate was 97.4%, 96.4%, and 98.5% for HD, LD, and PL groups, respectively. Overall, 99.4% of person-time reported no side effects throughout the study. Mild to moderate health events were recorded in some of the participants. Throughout the study duration, the total reported side effects with respect to complaints were 0.66%, 0.68%, and 0.48% for HD, LD, and PL, respectively. Symptoms included nausea, vomiting, diarrhea, flatulence, abdominal discomfort, heartburn and dizziness. These side effects were neither dose-dependent nor statistically significant among the three groups. Also, some participants (in all groups) reported having increased appetite in the course of the study. No significant differences were shown in hematology, liver and kidney function, electrolytes, and vital signs in the three groups. These findings demonstrate that application of NS clay for the protection of humans at high risk for aflatoxicosis may represent a novel and economically feasible approachItem NovaSil clay intervention in Ghanaians at high risk for aflatoxicosis: II. Reduction in biomarkers of aflatoxin exposure in blood and urine(Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment, 2008-05) Wang, P.; Afriyie-Gyawu, E.; Tang, Y.; Johnson, N.M.; Xu, L.; Tang, L.; Huebner, H.J.; Ankrah, N.A.; Ofori-adjei, D.et.alThe efficacy of NovaSil clay (NS) to reduce aflatoxin (AF) biomarkers of exposure was evaluated in 656 blood samples and 624 urine samples collected from study participants during a 3-month phase IIa clinical intervention trial in Ghana. NS was delivered before meals via capsules. Serum AFB1–albumin adduct was measured by radioimmunoassay and urinary AFM1 metabolites were quantified by immunoaffinity-high-performance liquid chromatography (HPLC)-fluorescence methods. Levels of AFB1–albumin adduct in serum samples collected at baseline and at 1 month were similar (p = 0.2354 and p = 0.3645, respectively) among the placebo (PL), low dose (LD, 1.5 g NS day−1), and high dose (HD, 3.0 g NS day−1) groups. However, the levels of AFB1–albumin adduct at 3 months were significantly decreased in both the LD group (p < 0.0001) and the HD group (p < 0.0001) compared with levels in the PL group. Levels of AFM1 in urine samples collected at baseline and at 1 month were not statistically different among the three study groups. However, a significant decrease (up to 58%) in the median level of AFM1 in samples collected at 3 months was found in the HD group when compared with the median level in the PL group (p < 0.0391). In addition, significant effects were found for dose, time, and dose–time interaction with serum AFB1–albumin adduct and dose–time interaction with urinary AFM1 metabolites. The results suggest that capsules containing NS clay can be used to reduce effectively the bioavailability of dietary AF based on a reduction of AF-specific biomarkers. © 2008 Taylor & Francis Group, LLC.Item PAH exposure in a Ghanaian population at high risk for aflatoxicosis(Sci Total Environ. 407(6): 1886-91, 2009) Ofori-Adjei, D.; Johnson, N.M.; Afriyie-Gyawu, E.; Huebner, H.; Marroquin-Cardona, A.; Robinson, A.; Tang, L.; Xu, L.; Ankrah, N.A.; Ofori-Adjei, D.; Jolly, P.E.; Williams, J.H.; Wang, J.S.; Phillips, T.D.It was postulated that a population in sub-Saharan Africa, known to be at high risk for aflatoxicosis due to frequent ingestion of aflatoxin (AF)-contaminated foods could also be exposed to polycyclic aromatic hydrocarbons (PAHs) from a variety of environmental sources. Previously, participants in this population were shown to be highly exposed to AFs, and this exposure was significantly reduced by intervention with NovaSil clay (NS). Objectives of this study were 1) to assess PAH exposure in participants from the AF study using urinary biomarker 1-hydroxypyrene (1-OHP); 2) examine the effect of NS clay and placebo (cellulose) treatment on 1-OHP levels; and 3) determine potential association(s) between AF and PAH exposures. A clinical trial was conducted in 177 Ghanaians who received either NS capsules as high dose or low dose, or placebo (cellulose) for a period of 3 months. At the start and end of the study, urine samples were analyzed for 1-OHP. Of the 279 total samples, 98.9% had detectable levels of 1-OHP. Median 1-OHP excretion in nonsmokers was 0.64 micromol/mol creatinine at baseline and 0.69 micromol/mol creatinine after 3 months. Samples collected at both time points did not show significant differences between placebo and NS-treated groups. There was no linear correlation between 1-OHP and AF-albumin adduct levels. Results show that this population is highly exposed to PAHs (and AFs), that NS and cellulose treatment had no statistically significant effect on 1-OHP levels, and that this urinary biomarker was not linearly related with AF exposure.Item Safety of "sachet water" and raw milk(Ghana Med. Journal 41(2): 37, 2007) Ofori-Adjei, D.; Afriyie-Gyawu, E.; Ankrah, N. A.; Huebner, H.J.; Ofosuhene, M.; Kumi, J.; Johnson, N.M.; Tang, L.; Xu, L.; Jolly, P.E.; Ellis, W.O.; Williams, J.H.; Wang, J.S.; Phillips, T.D.A 3-month double-blind and placebo-controlled, phase IIa clinical trial was conducted in Ghana to investigate the safety, tolerance and aflatoxin-sorption efficacy of dietary NovaSil (NS). Volunteers (507 subjects) were clinically screened to evaluate their general health, pregnancy status and blood AFB(1)-albumin adduct levels. Of these subjects, 177 were randomly assigned to three groups: high-dose (HD), low-dose (LD) and placebo-control (PL) groups receiving 3.0, 1.5 and 0 g NS day(-1) in capsules. Trained study-monitors supervised NS capsule administration to participants and recorded side-effects daily. Physical examinations were performed monthly. Blood and urine samples were collected for laboratory analysis. Approximately 92% of the participants (162 of 177) completed the study and compliance rate was over 97%. Overall, 99.5% of person x time reported no side-effects throughout the study. Mild to moderate health events (approximately 0.5% of person x time) were recorded in some participants. Symptoms included nausea, diarrhea, heartburn and dizziness. These side-effects were statistically similar among all three groups. No significant differences were shown in hematology, liver and kidney function or electrolytes in the three groups. These findings demonstrate that NS clay is apparently safe and practical for the protection of humans against aflatoxins in populations at high risk for aflatoxicosis.