Publications by authors named "Adeyinka G Falusi"

16 Publications

  • Page 1 of 1

Whole-genome analysis of Nigerian patients with breast cancer reveals ethnic-driven somatic evolution and distinct genomic subtypes.

Nat Commun 2021 11 26;12(1):6946. Epub 2021 Nov 26.

Center for Clinical Cancer Genetics and Global Health, Department of Medicine, The University of Chicago, Chicago, IL, 60637, USA.

Black women across the African diaspora experience more aggressive breast cancer with higher mortality rates than white women of European ancestry. Although inter-ethnic germline variation is known, differential somatic evolution has not been investigated in detail. Analysis of deep whole genomes of 97 breast cancers, with RNA-seq in a subset, from women in Nigeria in comparison with The Cancer Genome Atlas (n = 76) reveal a higher rate of genomic instability and increased intra-tumoral heterogeneity as well as a unique genomic subtype defined by early clonal GATA3 mutations with a 10.5-year younger age at diagnosis. We also find non-coding mutations in bona fide drivers (ZNF217 and SYPL1) and a previously unreported INDEL signature strongly associated with African ancestry proportion, underscoring the need to expand inclusion of diverse populations in biomedical research. Finally, we demonstrate that characterizing tumors for homologous recombination deficiency has significant clinical relevance in stratifying patients for potentially life-saving therapies.
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http://dx.doi.org/10.1038/s41467-021-27079-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8626467PMC
November 2021

Cross-ancestry GWAS meta-analysis identifies six breast cancer loci in African and European ancestry women.

Nat Commun 2021 07 7;12(1):4198. Epub 2021 Jul 7.

Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA.

Our study describes breast cancer risk loci using a cross-ancestry GWAS approach. We first identify variants that are associated with breast cancer at P < 0.05 from African ancestry GWAS meta-analysis (9241 cases and 10193 controls), then meta-analyze with European ancestry GWAS data (122977 cases and 105974 controls) from the Breast Cancer Association Consortium. The approach identifies four loci for overall breast cancer risk [1p13.3, 5q31.1, 15q24 (two independent signals), and 15q26.3] and two loci for estrogen receptor-negative disease (1q41 and 7q11.23) at genome-wide significance. Four of the index single nucleotide polymorphisms (SNPs) lie within introns of genes (KCNK2, C5orf56, SCAMP2, and SIN3A) and the other index SNPs are located close to GSTM4, AMPD2, CASTOR2, and RP11-168G16.2. Here we present risk loci with consistent direction of associations in African and European descendants. The study suggests that replication across multiple ancestry populations can help improve the understanding of breast cancer genetics and identify causal variants.
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http://dx.doi.org/10.1038/s41467-021-24327-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8263739PMC
July 2021

Diagnostic Accuracy of HemotypeSC as a Point-of-Care Testing Device for Sickle Cell Disease: Findings from a Southwestern State in Nigeria and Implications for Patient Care in Resource-Poor Settings of sub-Saharan Africa.

Glob Pediatr Health 2021 19;8:2333794X211016789. Epub 2021 May 19.

University of Campinas, São Paulo State, Campinas, Brazil.

This study aimed to determine the performance of a rapid, point-of-care testing device (HemotypeSC)™ for diagnosing sickle cell disease (SCD) relative to 2 commonly-used methods compared to DNA polymerase chain reaction (PCR) as the reference standard. The diagnostic performance of (HemotypeSC)™ in diagnosing SCD and determining various other Hb genotypes relative to high performance liquid chromatography (HPLC) and cellulose acetate Hb electrophoresis in alkaline buffer (CAE) was investigated among 156 participants aged 4 to 23 years in Ekiti, Southwest Nigeria. PCR was considered as the reference method/gold standard. The sensitivity and specificity for SS, SC, AS, AC, and AA genotypes by HemotypeSC and HPLC when compared with PCR, were each 100%. Similarly, their positive and negative predictive values were each 100%. However, sensitivity and specificity for identifying these Hb genotypes by CAE were 100, 100, 96.5, 0, 99.2%, and 99, 100, 92.9, 0, 91.7%. Also, CAE did not identify any of the 2 HbAC individuals that were correctly identified by PCR and both HemotypeSC, and HPLC, thus representing 100% HbAC misdiagnosis. In conclusion, this study shows that HemotypeSC has perfect concordance with PCR and 100% accuracy in diagnosing SCD in the population tested. Its ease of use, accuracy and other attributes make it suitable for use in sub-Saharan Africa for rapid determination of Hb genotypes.
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http://dx.doi.org/10.1177/2333794X211016789DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8138286PMC
May 2021

Discovery and fine-mapping of height loci via high-density imputation of GWASs in individuals of African ancestry.

Am J Hum Genet 2021 04 12;108(4):564-582. Epub 2021 Mar 12.

The Charles R. Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.

Although many loci have been associated with height in European ancestry populations, very few have been identified in African ancestry individuals. Furthermore, many of the known loci have yet to be generalized to and fine-mapped within a large-scale African ancestry sample. We performed sex-combined and sex-stratified meta-analyses in up to 52,764 individuals with height and genome-wide genotyping data from the African Ancestry Anthropometry Genetics Consortium (AAAGC). We additionally combined our African ancestry meta-analysis results with published European genome-wide association study (GWAS) data. In the African ancestry analyses, we identified three novel loci (SLC4A3, NCOA2, ECD/FAM149B1) in sex-combined results and two loci (CRB1, KLF6) in women only. In the African plus European sex-combined GWAS, we identified an additional three novel loci (RCCD1, G6PC3, CEP95) which were equally driven by AAAGC and European results. Among 39 genome-wide significant signals at known loci, conditioning index SNPs from European studies identified 20 secondary signals. Two of the 20 new secondary signals and none of the 8 novel loci had minor allele frequencies (MAF) < 5%. Of 802 known European height signals, 643 displayed directionally consistent associations with height, of which 205 were nominally significant (p < 0.05) in the African ancestry sex-combined sample. Furthermore, 148 of 241 loci contained ≤20 variants in the credible sets that jointly account for 99% of the posterior probability of driving the associations. In summary, trans-ethnic meta-analyses revealed novel signals and further improved fine-mapping of putative causal variants in loci shared between African and European ancestry populations.
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http://dx.doi.org/10.1016/j.ajhg.2021.02.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8059339PMC
April 2021

Haematological indices of sickle cell patients with chronic leg ulcers on compression therapy.

Afr J Lab Med 2020 21;9(1):1037. Epub 2020 Dec 21.

Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Nigeria.

Background: Recurrent chronic leg ulcers and its are morbidities associated with sickle cell anaemia (SCA). Compression therapy increases the rate of healing of these ulcers and also decreases the rate of recurrence.

Objective: This study evaluated the haematological parameters of patients with SCA and chronic leg ulcers placed on high compression bandaging to provide data for improved ulcer management and prevention.

Methods: Eighteen patients with SCA and chronic leg ulcers were recruited for treatment by compression therapy in Ibadan, Nigeria, from March to June 2015. Eighteen SCA patients with no history of chronic leg ulcers were age and sex matched and recruited as controls. Blood samples, wound biopsies and swabs were collected at different time points for full blood count, microbiology, culture and antimicrobial susceptibility tests. Haemoglobin variants were quantified by high performance liquid chromatography. Fasting blood sugar was tested for leg ulcer patients to determine diabetic status.

Results: Ulcers ranged from 0.5 cm to 416 cm (median: 38.4 cm). Post-intervention ulcer size ranged from 0.0 cm to 272 cm (median: 18.6 cm, < 0.001); four ulcers completely healed. Compared to the control group, haematological indices at commencement of treatment were more severe in leg ulcer patients ( = 0.02). No patients with chronic leg ulcer was diabetic. Microorganisms isolated from the leg ulcers include sp., and .

Conclusion: Measures to improve haematological parameters during leg ulcer treatment in SCA patients should be taken to aid wound healing.
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http://dx.doi.org/10.4102/ajlm.v9i1.1037DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7756931PMC
December 2020

N-acetyltransferase 2 enzyme genotype-phenotype discordances in both HIV-negative and HIV-positive Nigerians.

Pharmacogenet Genomics 2019 07;29(5):106-113

Department of Pharmaceutical Chemistry, Faculty of Pharmacy.

Background: The N-acetyltransferase 2 (NAT2) enzyme has been understudied in Nigerians including genotype-phenotype association studies.

Objective: The aim of this study was NAT2 haplotype identification and genotype-phenotype investigations in HIV-positive and HIV-negative Nigerians.

Patients And Methods: Phenotypes included self-reported sulphonamide hypersensitivity survey, experimental and computational NAT2 phenotyping. The NAT2 gene was amplified by PCR. Gene sequencing used ABI 3730 and Haploview 4.2 for haplotype reconstruction. Genotype-phenotype analyses used the χ P-value and odds ratio with a 95% confidence interval.

Results: Self-reported sulphonamide hypersensitivity showed a prevalence of 3.1 and 12.4% in HIV-positive and HIV-negative Nigerians, respectively. NAT2 genetic variants 191G>A, 282C>T, 341T>C, 481C>T, 590G>A, 803A>G and 857G>A were not significantly different between both groups (odds ratio=0.87; 95% confidence interval: 0.54-1.38, P=0.55). Nine haplotypes: NAT2*4, NAT2*12A, NAT2*13A, NAT2*5B, NAT2*6A, NAT2*7B, NAT2*5C, NAT2*14B and NAT2*14A had frequencies more than 1%, whereas NAT2*12B had 1.1% in the HIV-positive and 0.4% in the HIV-negative group. Overall, slow acetylator haplotypes made up 68%. The NAT2*12 signature single-nucleotide polymorphism was in high linkage disequilibrium with signature single-nucleotide polymorphism for NAT2*13 (D'=0.97, r=0.61) and NAT2*5 (D'=0.98, r=0.64). Genotype-phenotype association analysis showed haplotypes NAT2*13A, NAT2*5C, NAT2*7B and NAT2*14A to be associated strongly with the slow metabolic phenotype (P=0.002, 0.029, 0.032 and 0.050, respectively). Computational phenotypes were similar, with 30.9, 66 and 3.1% for slow, intermediate and rapid acetylators, respectively, among HIV-positive Nigerians and 31.2, 66.3 and 2.5% among the HIV-negative group. Overall, slow phenotypes made up 31%.

Conclusion: NAT2 haplotype frequencies are similar in Nigerians, irrespective of HIV status, but genotype-phenotype discordances exist.
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http://dx.doi.org/10.1097/FPC.0000000000000373DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6542708PMC
July 2019

Author Correction: Characterization of Nigerian breast cancer reveals prevalent homologous recombination deficiency and aggressive molecular features.

Nat Commun 2019 01 14;10(1):288. Epub 2019 Jan 14.

Department of Surgery, Lagos State University Teaching Hospital, Ikeja, Lagos, Nigeria.

The original version of this Article contained an error in the author affiliations. The affiliation of Kevin P. White with Tempus Labs, Inc. Chicago, IL, USA was inadvertently omitted. This has now been corrected in both the PDF and HTML versions of the Article.
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http://dx.doi.org/10.1038/s41467-018-07886-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6331546PMC
January 2019

Characterization of Nigerian breast cancer reveals prevalent homologous recombination deficiency and aggressive molecular features.

Nat Commun 2018 10 16;9(1):4181. Epub 2018 Oct 16.

Department of Surgery, Lagos State University Teaching Hospital, Ikeja, Lagos, Nigeria.

Racial/ethnic disparities in breast cancer mortality continue to widen but genomic studies rarely interrogate breast cancer in diverse populations. Through genome, exome, and RNA sequencing, we examined the molecular features of breast cancers using 194 patients from Nigeria and 1037 patients from The Cancer Genome Atlas (TCGA). Relative to Black and White cohorts in TCGA, Nigerian HR + /HER2 - tumors are characterized by increased homologous recombination deficiency signature, pervasive TP53 mutations, and greater structural variation-indicating aggressive biology. GATA3 mutations are also more frequent in Nigerians regardless of subtype. Higher proportions of APOBEC-mediated substitutions strongly associate with PIK3CA and CDH1 mutations, which are underrepresented in Nigerians and Blacks. PLK2, KDM6A, and B2M are also identified as previously unreported significantly mutated genes in breast cancer. This dataset provides novel insights into potential molecular mechanisms underlying outcome disparities and lay a foundation for deployment of precision therapeutics in underserved populations.
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http://dx.doi.org/10.1038/s41467-018-06616-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6191428PMC
October 2018

Inherited Breast Cancer in Nigerian Women.

J Clin Oncol 2018 10 21;36(28):2820-2825. Epub 2018 Aug 21.

Yonglan Zheng, Shengfeng Wang, Dezheng Huo, Toshio F. Yoshimatsu, Jing Zhang, Gabriela E.S. Felix, and Olufunmilayo I. Olopade, The University of Chicago, Chicago, IL; Tom Walsh, Suleyman Gulsuner, Silvia Casadei, Ming K. Lee, and Mary-Claire King, University of Washington, Seattle, WA; Temidayo O. Ogundiran, Adeyinka Ademola, Adeyinka G. Falusi, Abideen O. Oluwasola, Adewumi Adeoye, Abayomi Odetunde, Chinedum P. Babalola, Oladosu A. Ojengbede, Stella Odedina, Imaria Anetor, University of Ibadan; Clement A. Adebamowo, Centre for Bioethics and Research, Ibadan, Oyo, Nigeria, and University of Maryland School of Medicine, Baltimore, MD; and Gabriela E.S. Felix, Fundação Oswaldo Cruz and Universidade Federal da Bahia, Bahia, Brazil.

Purpose: Among Nigerian women, breast cancer is diagnosed at later stages, is more frequently triple-negative disease, and is far more frequently fatal than in Europe or the United States. We evaluated the contribution of an inherited predisposition to breast cancer in this population.

Patients And Methods: Cases were 1,136 women with invasive breast cancer (mean age at diagnosis, 47.5 ± 11.5 years) ascertained in Ibadan, Nigeria. Patients were selected regardless of age at diagnosis, family history, or prior genetic testing. Controls were 997 women without cancer (mean age at interview, 47.0 ± 12.4 years) from the same communities. BROCA panel sequencing was used to identify loss-of-function mutations in known and candidate breast cancer genes.

Results: Of 577 patients with information on tumor stage, 86.1% (497) were diagnosed at stage III (241) or IV (256). Of 290 patients with information on tumor hormone receptor status and human epidermal growth factor receptor 2, 45.9% (133) had triple-negative breast cancer. Among all cases, 14.7% (167 of 1,136) carried a loss-of-function mutation in a breast cancer gene: 7.0% in BRCA1, 4.1% in BRCA2, 1.0% in PALB2, 0.4% in TP53, and 2.1% in any of 10 other genes. Odds ratios were 23.4 (95% CI, 7.4 to 73.9) for BRCA1 and 10.3 (95% CI, 3.7 to 28.5) for BRCA2. Risks were also significantly associated with PALB2 (11 cases, zero controls; P = .002) and TP53 (five cases, zero controls; P = .036). Compared with other patients, BRCA1 mutation carriers were younger ( P < .001) and more likely to have triple-negative breast cancer ( P = .028).

Conclusion: Among Nigerian women, one in eight cases of invasive breast cancer is a result of inherited mutations in BRCA1, BRCA2, PALB2, or TP53, and breast cancer risks associated with these genes are extremely high. Given limited resources, prevention and early detection services should be especially focused on these highest-risk women.
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http://dx.doi.org/10.1200/JCO.2018.78.3977DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6161833PMC
October 2018

Characterizing Genetic Susceptibility to Breast Cancer in Women of African Ancestry.

Cancer Epidemiol Biomarkers Prev 2017 07 4;26(7):1016-1026. Epub 2017 Apr 4.

Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee.

Genome-wide association studies have identified approximately 100 common genetic variants associated with breast cancer risk, the majority of which were discovered in women of European ancestry. Because of different patterns of linkage disequilibrium, many of these genetic markers may not represent signals in populations of African ancestry. We tested 74 breast cancer risk variants and conducted fine-mapping of these susceptibility regions in 6,522 breast cancer cases and 7,643 controls of African ancestry from three genetic consortia (AABC, AMBER, and ROOT). Fifty-four of the 74 variants (73%) were found to have ORs that were directionally consistent with those previously reported, of which 12 were nominally statistically significant ( < 0.05). Through fine-mapping, in six regions (), we observed seven markers that better represent the underlying risk variant for overall breast cancer or breast cancer subtypes, whereas in another two regions (), we identified suggestive evidence of signals that are independent of the reported index variant. Overlapping chromatin features and regulatory elements suggest that many of the risk alleles lie in regions with biological functionality. Through fine-mapping of known susceptibility regions, we have revealed alleles that better characterize breast cancer risk in women of African ancestry. The risk alleles identified represent genetic markers for modeling and stratifying breast cancer risk in women of African ancestry. .
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http://dx.doi.org/10.1158/1055-9965.EPI-16-0567DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5500414PMC
July 2017

Genome-wide association studies in women of African ancestry identified 3q26.21 as a novel susceptibility locus for oestrogen receptor negative breast cancer.

Hum Mol Genet 2016 11;25(21):4835-4846

Department of Epidemiology, Gillings School of Global Public Health, and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA.

Multiple breast cancer loci have been identified in previous genome-wide association studies, but they were mainly conducted in populations of European ancestry. Women of African ancestry are more likely to have young-onset and oestrogen receptor (ER) negative breast cancer for reasons that are unknown and understudied. To identify genetic risk factors for breast cancer in women of African descent, we conducted a meta-analysis of two genome-wide association studies of breast cancer; one study consists of 1,657 cases and 2,029 controls genotyped with Illumina’s HumanOmni2.5 BeadChip and the other study included 3,016 cases and 2,745 controls genotyped using Illumina Human1M-Duo BeadChip. The top 18,376 single nucleotide polymorphisms (SNP) from the meta-analysis were replicated in the third study that consists of 1,984 African Americans cases and 2,939 controls. We found that SNP rs13074711, 26.5 Kb upstream of TNFSF10 at 3q26.21, was significantly associated with risk of oestrogen receptor (ER)-negative breast cancer (odds ratio [OR]=1.29, 95% CI: 1.18-1.40; P = 1.8 × 10 − 8). Functional annotations suggest that the TNFSF10 gene may be involved in breast cancer aetiology, but further functional experiments are needed. In addition, we confirmed SNP rs10069690 was the best indicator for ER-negative breast cancer at 5p15.33 (OR = 1.30; P = 2.4 × 10 − 10) and identified rs12998806 as the best indicator for ER-positive breast cancer at 2q35 (OR = 1.34; P = 2.2 × 10 − 8) for women of African ancestry. These findings demonstrated additional susceptibility alleles for breast cancer can be revealed in diverse populations and have important public health implications in building race/ethnicity-specific risk prediction model for breast cancer.
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http://dx.doi.org/10.1093/hmg/ddw305DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5975608PMC
November 2016

Phenotyping and genotyping of CYP2C19 using comparative metabolism of proguanil in sickle-cell disease patients and healthy controls in Nigeria.

Pharmacol Res Perspect 2016 10 22;4(5):e00252. Epub 2016 Aug 22.

Department of Pharmaceutical Chemistry Faculty of Pharmacy University of Ibadan Ibadan Nigeria; Genetic and Bioethics Unit Institute of Advanced Medical Research and Training (IMRAT) College of Medicine University of Ibadan Ibadan Nigeria.

Polymorphic expression of metabolic enzymes have been identified as one of the key factors responsible for the interindividual/ethnic/racial variability in drug metabolism and effect. In Nigeria, there is a disproportionately high incidence of sickle-cell disease (SCD), a condition characterized by painful crisis frequently triggered by malaria. Proguanil, a substrate of the polymorphic CYP2C19, is a chemoprophylactic antimalarial drug widely used among SCD patients in Nigeria. This study aimed to conduct a comparative CYP2C19 phenotyping among SCD patients and healthy controls and to compare the results with those previously reported. One hundred seventy-seven unrelated subjects comprising 131 SCD patients and 46 non-SCD volunteers were phenotyped. This was carried out by collecting pooled urine samples over 8 h following PG administration. Proguanil and its major CYP2C19-dependent metabolites were measured by high-performance liquid chromatography. Metabolic ratios (MRs) were computed and employed in classifying subjects into poor or extensive metabolizers. Among SCD group, 130 (99.2%) were extensive metabolizers (EMs) and 1 (0.8%) was poor metabolizer (PM) of PG, while 95.7 and 4.3% non-SCDs were EMs and PMs, respectively. MRs ranged from 0.02 to 8.70 for SCD EMs and from 0.22 to 8.33 for non-SCD EMs Two non-SCDs with MRs of 18.18 and 25.76 and the SCD with MR of 16.77 regarded as PMs had earlier been genotyped as CYP2C19*2/*2. Poor metabolizers of proguanil in SCD patients are reported for the first time. Regardless of clinical significance, a difference in metabolic disposition of proguanil and CYP2C19 by SCDs and non-SCDs was established.
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http://dx.doi.org/10.1002/prp2.252DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5045938PMC
October 2016

Significant Pharmacokinetic Interactions Between Quinine and Ampicillin-Cloxacillin Combination.

Drugs R D 2016 Jun;16(2):193-203

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Ibadan, Ibadan, Oyo State, Nigeria.

Introduction: The co-existence of malaria with bacterial infections is common in the tropics, hence the concurrent use of antimalarials and antibiotics.

Objective: This study aimed to investigate the effect on pharmacokinetics and antimicrobial activity of co-administration of quinine and combined ampicillin-cloxacillin.

Methods: In total, 14 healthy adults received single oral doses of ampicillin-cloxacillin combination alone and with quinine in a randomized crossover manner. Urine samples collected at predetermined intervals over 48 h were analysed. The effect of quinine on minimum inhibitory concentrations (MICs) of ampicillin and cloxacillin were determined against Staphylococcus aureus by agar diffusion, agar dilution, and broth dilution.

Results: Quinine significantly reduced the rate and extent of excretion of ampicillin and cloxacillin (p < 0.0002). The total amounts of ampicillin and cloxacillin excreted unchanged (Du(∞)) alone were 217.10 ± 53.82 and 199.0 ± 64.29 mg versus 126.40 ± 50.63 and 135.20 ± 52.24 mg, respectively, with quinine. Respective maximum excretion rates (dDu/dt max) for ampicillin and cloxacillin were 43.55 ± 19.41 and 77.64 ± 29.65 mg/h alone versus 18.01 ± 8.52 and 53.16 ± 20.72 mg/h with quinine. This indicates a significant reduction in Du(∞)and dDu/dt max by 41.78 and 58.65 % for ampicillin and 32.06 and 31.53 % for cloxacillin. Conversely, the disposition of quinine was unaffected by ampicillin-cloxacillin (p > 0.1). The MIC of antibiotics alone versus with quinine, respectively, were 0.11 ± 0.04 and 0.78 ± 0.1 µg/ml for ampicillin, and 0.18 ± 0.1 and 0.92 ± 0.4 µg/ml for cloxacillin, with a five- to sevenfold increase (p > 0.01); indicating a decrease in antimicrobial activity by quinine.

Conclusions: Quinine therefore, reduced the bioavailability and the antimicrobial activity of ampicillin-cloxacillin upon co-administration, which may have therapeutic implications. Caution is required with the co-administration of these medicines.
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http://dx.doi.org/10.1007/s40268-016-0128-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4875923PMC
June 2016

Fine mapping of breast cancer genome-wide association studies loci in women of African ancestry identifies novel susceptibility markers.

Carcinogenesis 2013 Jul 8;34(7):1520-8. Epub 2013 Mar 8.

Department of Medicine, Center for Clinical Cancer Genetics and Global Health, The University of Chicago, Chicago, IL 60637, USA.

Numerous single nucleotide polymorphisms (SNPs) associated with breast cancer susceptibility have been identified by genome-wide association studies (GWAS). However, these SNPs were primarily discovered and validated in women of European and Asian ancestry. Because linkage disequilibrium is ancestry-dependent and heterogeneous among racial/ethnic populations, we evaluated common genetic variants at 22 GWAS-identified breast cancer susceptibility loci in a pooled sample of 1502 breast cancer cases and 1378 controls of African ancestry. None of the 22 GWAS index SNPs could be validated, challenging the direct generalizability of breast cancer risk variants identified in Caucasians or Asians to other populations. Novel breast cancer risk variants for women of African ancestry were identified in regions including 5p12 (odds ratio [OR] = 1.40, 95% confidence interval [CI] = 1.11-1.76; P = 0.004), 5q11.2 (OR = 1.22, 95% CI = 1.09-1.36; P = 0.00053) and 10p15.1 (OR = 1.22, 95% CI = 1.08-1.38; P = 0.0015). We also found positive association signals in three regions (6q25.1, 10q26.13 and 16q12.1-q12.2) previously confirmed by fine mapping in women of African ancestry. In addition, polygenic model indicated that eight best markers in this study, compared with 22 GWAS-identified SNPs, could better predict breast cancer risk in women of African ancestry (per-allele OR = 1.21, 95% CI = 1.16-1.27; P = 9.7 × 10(-16)). Our results demonstrate that fine mapping is a powerful approach to better characterize the breast cancer risk alleles in diverse populations. Future studies and new GWAS in women of African ancestry hold promise to discover additional variants for breast cancer susceptibility with clinical implications throughout the African diaspora.
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http://dx.doi.org/10.1093/carcin/bgt090DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3697898PMC
July 2013

High prevalence of BRCA1 and BRCA2 mutations in unselected Nigerian breast cancer patients.

Int J Cancer 2012 Sep 27;131(5):1114-23. Epub 2012 Jan 27.

Department of Medicine, University of Chicago, Chicago, IL 60637, USA.

Inherited mutations in the BRCA1 and BRCA2 genes are the strongest genetic predictors of breast cancer and are the primary causes of familial breast/ovarian cancer syndrome. The frequency, spectrum and penetrance of mutant BRCA1/BRCA2 alleles have been determined for several populations, but little information is available for populations of African ancestry, who suffer a disproportionate burden of early onset breast cancer. We have performed complete sequence analysis of all BRCA1 and BRCA2 exons and intron-exon boundaries for 434 Nigerian breast cancer patients from the University College Hospital in Ibadan, Nigeria. In contrast to previous suggestions that BRCA1/BRCA2 mutation frequencies are low or undetectable in African American populations, we find that Nigerian breast cancer patients have an exceptionally high frequency of BRCA1 and BRCA2 mutations (7.1 and 3.9%, respectively). Sixteen different BRCA1 mutations were detected, seven of which have never been reported previously, while thirteen different BRCA2 mutations were seen, six of which were previously unreported. Thus, our data support enrichment for genetic risk factors in this relatively young cohort. To improve breast cancer outcomes, we suggest that family-based models of risk assessment and genetic counseling coupled with interventions to reduce breast cancer risk should be broadly disseminated in Nigeria and other underserved and understudied populations.
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http://dx.doi.org/10.1002/ijc.27326DOI Listing
September 2012

Establishment of a standing ethics/institutional review board in a nigerian university: a blueprint for developing countries.

J Empir Res Hum Res Ethics 2007 Mar;2(1):21-30

Institute for Advanced Medical Research and Training, University of Ibadan, Ibadan, Nigeria.

AN ETHICS/INSTITUTIONAL REVIEW BOARD (IRB) was established according to International standards at the University of Ibadan in Nigeria. To achieve this, a private-public partnership was developed to support a review of prevailing practice and the development of necessary infrastructure for an effective IRB. An internationally registered and well-constituted IRB with a federal-wide assurance (FWA) from the National Institute of Health in the United States was established within a year. Over a 3-year period, the number of proposals reviewed increased by 150% while time to approval decreased by 62%. International collaboration and external research funding has increased substantially. These findings support our initial supposition that the development of a properly functioning IRB can be a catalyst for increased research productivity at academic centers in developing countries while ensuring the protection of vulnerable human research subjects. The University of Ibadan is now assisting other academic Institutions in Nigeria and sub-Saharan Africa with the establishment of their own IRBs.
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http://dx.doi.org/10.1525/jer.2007.2.1.21DOI Listing
March 2007
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