James Gomes
@uottawa.ca
University of Ottawa
Scopus Publications
- Cytotoxic Potencies of Zinc Oxide Nanoforms in A549 and J774 Cells
Nazila Nazemof, Dalibor Breznan, Yasmine Dirieh, Erica Blais, Linda J. Johnston, et al.
Nanomaterials, 2024
Zinc oxide nanoparticles (NPs) are used in a wide range of consumer products and in biomedical applications, resulting in an increased production of these materials with potential for exposure, thus causing human health concerns. Although there are many reports on the size-related toxicity of ZnO NPs, the toxicity of different nanoforms of this chemical, toxicity mechanisms, and potency determinants need clarification to support health risk characterization. A set of well-characterized ZnO nanoforms (e.g., uncoated ca. 30, 45, and 53 nm; coated with silicon oil, stearic acid, and (3-aminopropyl) triethoxysilane) were screened for in vitro cytotoxicity in two cell types, human lung epithelial cells (A549), and mouse monocyte/macrophage (J774) cells. ZnO (bulk) and ZnCl2 served as reference particles. Cytotoxicity was examined 24 h post-exposure by measuring CTB (viability), ATP (energy metabolism), and %LDH released (membrane integrity). Cellular oxidative stress (GSH-GSSG) and secreted proteins (targeted multiplex assay) were analyzed. Zinc oxide nanoform type-, dose-, and cell type-specific cytotoxic responses were seen, along with cellular oxidative stress. Cell-secreted protein profiles suggested ZnO NP exposure-related perturbations in signaling pathways relevant to inflammation/cell injury and corresponding biological processes, namely reactive oxygen species generation and apoptosis/necrosis, for some nanoforms, consistent with cellular oxidative stress and ATP status. The size, surface area, agglomeration state and metal contents of these ZnO nanoforms appeared to be physicochemical determinants of particle potencies. These findings warrant further research on high-content “OMICs” to validate and resolve toxicity pathways related to exposure to nanoforms to advance health risk-assessment efforts and to inform on safer materials. - Polybrominated diphenyl ether (PBDE) exposure and adverse maternal and infant health outcomes: Systematic review
J. Gomes, M. Begum, P. Kumarathasan
Chemosphere, 2024 - Barriers and facilitators for interventions to improve ART adherence in Sub-Saharan African countries: A systematic review and meta-analysis
Amos Buh, Raywat Deonandan, James Gomes, Alison Krentel, Olanrewaju Oladimeji, et al.
Plos One, 2023
Background The HIV/AIDS pandemic remains a significant public health issue, with sub-Saharan Africa (SSA) at its epicentre. Although antiretroviral therapy (ART) has been introduced to decrease new infections and deaths, SSA reports the highest incidence of HIV/AIDS, constituting two-thirds of the global new infections. This review aimed to elucidate the predominant barriers and facilitators influencing ART adherence and to identify effective strategies to enhance ART adherence across SSA. Methods A comprehensive review was conducted on studies examining barriers to ART adherence and interventions to boost adherence among HIV-positive adults aged 15 and above in SSA, published from January 2010 onwards. The research utilized databases like Medline Ovid, CINAHL, Embase, and Scopus. Included were experimental and quasi-experimental studies, randomized and non-randomized controlled trials, comparative before and after studies, and observational studies such as cross-sectional, cohort, prospective and retrospective studies. Two independent reviewers screened the articles, extracted pertinent data, and evaluated the studies’ methodological integrity using Joanna Briggs Institute’s standardized appraisal tools. The compiled data underwent both meta-analysis and narrative synthesis. Results From an initial pool of 12,538 papers, 45 were selected (30 for narrative synthesis and 15 for meta-analysis). The identified barriers and facilitators to ART adherence were categorized into seven principal factors: patient-related, health system-related, medication-related, stigma, poor mental health, socioeconomic and socio-cultural-related factors. Noteworthy interventions enhancing ART adherence encompassed counselling, incentives, mobile phone short message service (SMS), peer delivered behavioural intervention, community ART delivery intervention, electronic adherence service monitoring device, lay health worker lead group intervention and food assistance. The meta-analysis revealed a statistically significant difference in ART adherence between the intervention and control groups (pooled OR = 1.56, 95%CI:1.35–1.80, p = <0.01), with evidence of low none statistically significant heterogeneity between studies (I2 = 0%, p = 0.49). Conclusion ART adherence in SSA is influenced by seven key factors. Multiple interventions, either standalone or combined, have shown effectiveness in enhancing ART adherence. To optimize ART’s impact and mitigate HIV’s prevalence in SSA, stakeholders must consider these barriers, facilitators, and interventions when formulating policies or treatment modalities. For sustained positive ART outcomes, future research should target specific underrepresented groups like HIV-infected children, adolescents, and pregnant women in SSA to further delve into the barriers, facilitators and interventions promoting ART adherence. - Barriers and facilitators to ART adherence among ART non-adherence people living with HIV in Cameroon: A qualitative phenomenological study
Amos Buh, Raywat Deonandan, James Gomes, Alison Krentel, Olanrewaju Oladimeji, et al.
Plos One, 2023
Background Antiretroviral therapy (ART) needs to be taken for life with near perfect levels of adherence for it to be effective. Nonetheless, ART non-adherence is still observed in sub-Saharan African (SSA) countries such as Cameroon. The objective of this study was to assess the factors influencing non-adherence and or adherence among people living with HIV (PLWH) who have experienced non-adherence to ART in Cameroon. Methods A descriptive qualitative study of PLWH who have experienced non-adherence with ART in Cameroon was conducted. Data were collected using in-depth interviews. Collected data were analyzed using the NVIVO 12 software. Results In total, 43 participants participated in this study. The Southwest and Littoral regions each contributed 15 (34.88%) of participants, participants’ mean age was 37.1 years (SD: 9.81) and majority 34 (82.93%) were females. ART adherence barriers include those related to patient (forgetfulness, business with other things, unwillingness to swallow drugs daily), medication (side effects), health service (arrogance of caregivers, occasional drug shortages at treatment centre, poor counseling of patient), stigma (fear of status disclosure), use of alternative treatment (traditional medicine, prayers and deliverance), resource limitation (limited food, limited finances), environmental/social (limited or no home support), and political instability (disruption of free circulation by ghost towns, roadblocks and gunshots in some regions). ART adherence facilitators include social support (family and peer support), aligning treatment with patient’s daily routines (align ART with schedule of family members), use of reminders (phone alarm, sound of church bell), health sector/caregiver support (messages to patient, financial support, proper counseling), and patient’s awareness of HIV status/ART knowledge (awareness of HIV positive status, Knowledge of ART benefits). Conclusion ART adherence barriers in Cameroon include those related to patient, medication, health service, stigma, use of alternative treatment, resource limitation, environmental/social, and political instability. ART adherence facilitators include social support, aligning treatment with patient’s daily routines, use of reminders, health sector/caregiver support, and patient’s awareness of HIV status/ART knowledge. Given these barriers and facilitators, continuous information provision and consistent support both from patients’ families and caregivers are needed to improve adherence among patients. Further studies including many regions and larger samples using both in-depth and focused group discussions as well as quantitative approaches are required to uncover the burden related to ART non-adherence. - Prevalence and factors associated with HIV treatment non-adherence among people living with HIV in three regions of Cameroon: A cross-sectional study
Amos Buh, Raywat Deonandan, James Gomes, Alison Krentel, Olanrewaju Oladimeji, et al.
Plos One, 2023
Background In Cameroon, HIV care decentralization is enforced as a national policy, but follow-up of people living with HIV (PLWH) is provider-driven, with little patient education and limited patient participation in clinical surveillance. These types of services can result in low antiretroviral therapy (ART) adherence. The objective of this study was to assess the prevalence and predictors of ART non-adherence among PLWH in Cameroon. Methods A cross-sectional descriptive study of PLWH in HIV treatment centres in Cameroon was conducted. Only PLWH, receiving treatment in a treatment centre within the country, who had been on treatment for at least six months and who were at least 21 years old were included in the study. Individuals were interviewed about their demographics and ART experiences. Data were collected using a structured interviewer-administered questionnaire and analyzed using STATA version 14. Results A total of 451 participants participated in this study, 33.48% were from the country’s Southwest region. Their mean age was 43.42 years (SD: 10.42), majority (68.89%) were females. Overall proportion of ART non-adherence among participants was 37.78%, 35.88% missed taking ART twice in the last month. Reasons for missing ART include forgetfulness, business and traveling without drugs. Over half of participants (54.67%) know ART is life-long, 53.88% have missed ART service appointments, 7.32% disbelieve in ART benefits, 28.60% think taking ART gives unwanted HIV Status reminder and 2.00% experienced discrimination seeking ART services. In the multivariate analysis, odds of ART non-adherence in participants aged 41 and above was 0.35 times (95%CI: 0.14, 0.85) that in participants aged 21–30 years, odds of ART non-adherence comparing participants who attained only primary education to those who attained higher than secondary education was 0.57 times (95%CI: 0.33, 0.97) and the odds of ART non-adherence in participants who are nonalcohol consumers was 0.62 times (95%CI: 0.39, 0.98) that in alcohol consumers. Conclusion High proportion of participants are ART non-adherent, and the factors significantly associated with ART non-adherence include age, education and alcohol consumption. However, some reasons for missing ART are masked in participants’ limited knowledge in taking ART, disbelief in ART benefits, feelings that ART gives unwanted HIV status reminder and experiencing discrimination when seeking ART services. These underscores need to improve staff (health personnel) attitudes, staff-patient-communication, and proper ART prior initiation counselling of patients. Future studies need to focus on assessing long-term ART non-adherence trends and predictors using larger samples in many treatment centres and regions. - Residents' perception and worldview about radon control policy in Canada: A pro-equity social justice lens
Selim M. Khan, James Gomes, Anne-Marie Nicol
Frontiers in Public Health, 2022
Radon is a potent indoor air pollutant, especially in radon prone areas and in countries with long winters. As the second top lung carcinogen, radon is disproportionately affecting certain population subgroups. While many provinces have taken sporadic actions, the equity issue has remained unaddressed across all policy measures. Attempts to enforce radon guidelines and enact building regulations without considering residents' views have proved ineffective. Research linking residents' radon risk perception and worldviews regarding radon control policy is lacking in Canada. We applied mixed (quantitative and qualitative) methods in a pro-equity social justice lens to examine the variations in residents' risk perception, access to risk communication messages, and worldviews about risk management across the sociodemographic strata. Triangulation of the quantitative and qualitative findings strengthened the evidence base to identify challenges and potential solutions in addressing the health risk through upstream policy actions. Enacting radon control policy requires actions from all levels of governments and relevant stakeholders to ensure equal opportunities for all residents to take the preventive and adaptive measures. Small sample size limited the scope of findings for generalization. Future studies can examine the differential impacts of radon health risk as are determined by various sociodemographic variables in a representative national cohort. - In vitro toxicity screening of amorphous silica nanoparticles using mitochondrial fraction exposure followed by MS-based proteomic analysis
Premkumari Kumarathasan, Nazila Nazemof, Dalibor Breznan, Erica Blais, Hiroyuki Aoki, et al.
Analyst, 2022
Application of mitochondrial proteomic analysis in toxicity screening of amorphous silica nanoforms. Concordance between SiNP exposure-related perturbations in mitochondrial proteins and cellular ATP responses. - Adherence barriers and interventions to improve ART adherence in Sub-Saharan African countries: A systematic review protocol
Amos Buh, Raywat Deonandan, James Gomes, Alison Krentel, Olanrewaju Oladimeji, et al.
Plos One, 2022
Background The HIV/AIDS pandemic continues to be a major public health concern, particularly in Sub-Saharan Africa (SSA). Despite efforts to reduce new infections and deaths with the use of antiretroviral therapy (ART), SSA countries continue to bear the heaviest burden of HIV/AIDS globally, accounting for two-thirds of global new infections. The goal of this review is to identify common barriers to ART adherence as well as common effective interventions that can be implemented across SSA countries to improve ART adherence. Methods A systematic review of published studies on adult HIV-positive patients aged 15 or above, that have assessed the barriers to ART adherence and interventions improving patients’ adherence to ART in SSA countries shall be conducted. We will conduct electronic searches for articles that have been published starting from January 2010 onwards. The databases that shall be searched will include Medline Ovid, CINAHL, Embase, and Scopus. The review will include experimental and quasi-experimental studies such as randomized and non-randomized controlled trials as well as comparative before and after studies, and observational studies—cross-sectional studies, cohort studies, prospective and retrospective studies. Two independent reviewers will screen all identified studies, extract data and appraise the methodological quality of the studies using standard critical appraisal tools from the Joanna Briggs Institute. The extracted data will be subjected to a meta-analysis and narrative synthesis. Discussion This review will synthesize existing evidence on ART adherence barriers and strategies for improving patient adherence to ART in SSA countries. It will identify common barriers to adherence and common interventions proven to improve adherence across SSA. We anticipate that the findings of this review will provide information policy makers and stakeholders involved in the fight against HIV, will find useful in deriving better ways of not only retaining patients on treatment but having them adhere to their treatment. Review registration This protocol has been registered with the International Prospective Register of Systematic Reviews (PROSPERO); registration number CRD42021262256. - A Mixed Methods Population Health Approach to Explore Radon-Induced Lung Cancer Risk Perception in Canada
S. M. Khan, J. Gomes, S. Chreim
Cancer Control, 2021
Background Radon is a predominant indoor air pollutant and second leading cause of lung cancer in radon-prone areas. Despite the gravity of the health risk, residents in Canada have inadequate perception and taken minimal protective actions. Better perception of a risk motivates people to take preventive measures. Scholarship about radon health risk perception is lacking in Canada. We applied a mixed methods population health approach to explore the determinants shaping perception and actions of a resident population in Canada. Methods We conducted mixed surveys (n = 557) and qualitative bilingual interviews (n = 35) with both homeowners and tenants of Ottawa–Gatineau areas. The study explored residents' risk perception and adaptations factors. Descriptive, correlational and regression analyses described and established associations between quantitative variables. Thematic, inductive analyses identified themes in the qualitative data. A mixed methods analysis triangulated both results to draw a holistic perception of the health risk. Results Residents’ quantitative perceptions of radon health risk, smoking at home, synergistic risk perception, social influence and care for family were associated significantly with their intention to test for radon levels in their home, actual testing and mitigation. These results were explained further with the qualitative findings. Residents who had dual cognitive and emotional awareness of the risk were motivated enough to take preventive actions. Caring for family, knowing others who contracted lung cancer and financial capability were enablers, whereas lack of awareness and homeownership, cost of mitigation and stigma were obstacles to preventive actions. We also explored the dual subjective and objective aspects of risk perception that are influenced by micro- and macro-level determinants. Conclusions Inducing protective action to reduce risk requires comprehensive population-level interventions considering dual perceptions of the risk that can modify the risk determinants. Future research can explore the dual aspects of risk perception and unequal distribution of the risk factors. - Acellular oxidative potential assay for screening of amorphous silica nanoparticles
Dalibor Breznan, Nazila Nazemof, Filip Kunc, Myriam Hill, Djordje Vladisavljevic, et al.
Analyst, 2020
Rapid acellular screening of amorphous silica nanoforms of different sizes and surface modifications for their oxidative potential. - Maternal blood biomarkers and adverse pregnancy outcomes: a systematic review and meta-analysis
J. Gomes, F. Au, A. Basak, S. Cakmak, R. Vincent, et al.
Critical Reviews in Toxicology, 2019 - Radon interventions around the globe: A systematic review
Selim M. Khan, James Gomes, Daniel R. Krewski
Heliyon, 2019 - Radon, an invisible killer in Canadian homes: perceptions of Ottawa-Gatineau residents
Selim M. Khan, Daniel Krewski, James Gomes, Raywat Deonandan
Canadian Journal of Public Health, 2019 - A systematic review of the risk factors associated with the onset and progression of primary brain tumours
Pauline Quach, Reem El Sherif, James Gomes, Daniel Krewksi
Neurotoxicology, 2017 - Burden of neurological conditions in Canada
J. Gaskin, J. Gomes, S. Darshan, D. Krewski
Neurotoxicology, 2017 - Identification of risk factors associated with onset and progression of amyotrophic lateral sclerosis using systematic review and meta-analysis
Ming-Dong Wang, Julian Little, James Gomes, Neil R. Cashman, Daniel Krewski
Neurotoxicology, 2017 - Risk factors associated with the onset and progression of Alzheimer's disease: A systematic review of the evidence
Mona Hersi, Brittany Irvine, Pallavi Gupta, James Gomes, Nicholas Birkett, et al.
Neurotoxicology, 2017 - Systematic reviews of factors associated with the onset and progression of neurological conditions in humans: A methodological overview
Mona Hersi, Pauline Quach, Ming-Dong Wang, James Gomes, Janet Gaskin, et al.
Neurotoxicology, 2017 - Genetic variation associated with the occurrence and progression of neurological disorders
Julian Little, Caroline Barakat-Haddad, Rosemary Martino, Tamara Pringsheim, Helen Tremlett, et al.
Neurotoxicology, 2017 - Determinants of neurological disease: Synthesis of systematic reviews
Daniel Krewski, Caroline Barakat-Haddad, Jennifer Donnan, Rosemary Martino, Tamara Pringsheim, et al.
Neurotoxicology, 2017 - Ser422phosphorylation blocks human Tau cleavage by caspase-3: Biochemical implications to Alzheimer's Disease
Priya Sandhu, Mansur Mohammad Naeem, Chunyu Lu, Premkumari Kumarathasan, James Gomes, et al.
Bioorganic and Medicinal Chemistry Letters, 2017 - Infant and mother related outcomes from exposure to metals with endocrine disrupting properties during pregnancy
A. Rahman, P. Kumarathasan, J. Gomes
Science of the Total Environment, 2016 - Calcium role in human carcinogenesis: a comprehensive analysis and critical review of literature
Bernard Kadio, Sanni Yaya, Ajoy Basak, Koffi Djè, James Gomes, et al.
Cancer and Metastasis Reviews, 2016 - Blood metal levels and third trimester maternal plasma matrix metalloproteinases (MMPs)
Felicia Au, Agnieszka Bielecki, Erica Blais, Mandy Fisher, Sabit Cakmak, et al.
Chemosphere, 2016 - LDL-R promoting activity of peptides derived from human PCSK9 catalytic domain (153-421): Design, synthesis and biochemical evaluation
European Journal of Medicinal Chemistry, 2015
