Raboud J.,Toronto General Research Institute |
Raboud J.,University of Toronto |
Su D.,Toronto General Research Institute |
Burchell A.N.,University of Toronto |
And 16 more authors.
BMC Medical Research Methodology | Year: 2013
Background: Participation bias is a well-known phenomenon in epidemiologic research, where individuals consenting to research studies differ from individuals who are not able or willing to participate. These dissimilarities may limit the generalizability of results of research studies. Quantification of the participation bias is essential for the interpretation of research findings. Methods. The Ontario HIV Treatment Network Cohort Study (OCS) is an ongoing open cohort study of HIV positive individuals receiving care at one of 11 sites in Ontario. OCS participants from 4 sites were compared to non-participants (those who declined or were not approached) at those sites with regard to gender, age, HIV risk factor, CD4 count and viral load (VL). Generalized logit regression models were used to identify predictors of declining to participate or not being approached to participate. Results: Compared to participants (P) in the OCS, individuals who declined to participate (D) and those who were not approached (NA) were slightly younger (D:45, NA:44 vs P:46), less likely to be male (D: 71%, NA:75% vs P:88%), less likely to be Caucasian (D:41%, NA:57% vs P:72%) and less likely to be Canadian-born (D: 39%, NA: 52% vs P: 69%). Patients who were not approached to participate were less likely to have VL < 50 copies/mL than other patients (D: 75%, NA: 62%, P: 74%) and had lower CD4 counts than OCS participants (D: 450 cells/mm 3, NA: 420 cells/mm3, P: 480 cells/mm3). Conclusions: Significant demographic and clinical differences were found between OCS participants and non-participants. Extrapolation of research findings to other populations should be undertaken cautiously. © 2013 Raboud et al.; licensee BioMed Central Ltd.
Ward A.,University of Windsor |
Morettin A.,University of Windsor |
Shum D.,Windsor Regional Hospital |
Hudson J.W.,University of Windsor
BMC Cancer | Year: 2011
Background: Hepatocellular carcinoma (HCC), one of the most common cancers world-wide occurs twice as often in men compared to women. Predisposing conditions such as alcoholism, chronic viral hepatitis, aflatoxin B1 ingestion, and cirrhosis all contribute to the development of HCC.Methods: We used a combination of methylation specific PCR and bisulfite sequencing, qReal-Time PCR (qPCR), and Western blot analysis to examine epigenetic changes for the Polo-like kinases (Plks) during the development of hepatocellular carcinoma (HCC) in Plk4 heterozygous mice and murine embryonic fibroblasts (MEFs).Results: Here we report that the promoter methylation of Plk4 CpG islands increases with age, was more prevalent in males and that Plk4 epigenetic modification and subsequent downregulation of expression was associated with the development of HCC in Plk4 mutant mice. Interestingly, the opposite occurs with another Plk family member, Plk1 which was typically hypermethylated in normal liver tissue but became hypomethylated and upregulated in liver tumours. Furthermore, upon alcohol exposure murine embryonic fibroblasts exhibited increased Plk4 hypermethylation and downregulation along with increased centrosome numbers and multinucleation.Conclusions: These results suggest that aberrant Plk methylation is correlated with the development of HCC in mice. © 2011 Ward et al; licensee BioMed Central Ltd.
Ward A.,University of Windsor |
Sivakumar G.,University of Windsor |
Kanjeekal S.,Windsor Regional Cancer Center |
Hamm C.,Windsor Regional Cancer Center |
And 3 more authors.
Leukemia and Lymphoma | Year: 2015
Deregulation of Polo-like kinase (PLK) transcription via promoter methylation results in perturbations at the protein level, which has been associated with oncogenesis. Our objective was to further characterize the methylation profile for PLK1-4 in bone marrow aspirates displaying blood neoplasms as well as in cells grown in vitro. Clinically, we have determined that more than 70% of lymphoma and myelodysplastic syndrome (MDS)/leukemia bone marrow extracts display a hypermethylated PLK4 promoter region in comparison to the normal. Decreased PLK4 protein expression due to promoter hypermethylation was negatively correlated with JAK2 overexpression, a common occurrence in hematological malignancies. In vitro examination of the PLKs under biologically relevant condition of 5% O2 revealed that the highly conserved PLKs respond to lower oxygen tension at both the DNA and the protein level. These findings suggest that PLK promoter methylation status correlates with disease and tumorigenesis in blood neoplasms and could serve as a biomarker. © 2015 Informa UK, Ltd.
Chen Y.A.,St. Michaels Hospital |
Cervini P.,Windsor Regional Hospital |
Kirpalani A.,St. Michaels Hospital |
Vlachou P.A.,St. Michaels Hospital |
And 2 more authors.
Canadian Journal of Gastroenterology and Hepatology | Year: 2014
The authors report a case series describing four patients who developed small bowel obstruction following the use of psyllium seed husk as an oral contrast agent for computed tomography or magnetic resonance enterography. Radiologists who oversee computed tomography and magnetic resonance enterography should be aware of this potential complication when using psyllium seed husk and other bulking agents, particularly when imaging patients with known or suspected small bowel strictures or active inflammation. ©2014 Pulsus Group Inc. All rights reserved.
Valensi P.,Paris Nord University |
Shaban J.A.,Windsor Regional Hospital |
Bushnell D.M.,Health Research Associates |
Christensen T.L.,Novo Nordisk AS
Quality of Life Research | Year: 2010
Purpose: Understanding treatment satisfaction (TS) for diabetes is increasingly important as treatment options increase. This study examines treatment satisfaction with NovoMix® 30 in an observational study in patients with type 2 diabetes. Methods: The DiabMedSat assesses Overall, Treatment Burden, Symptom and Efficacy Treatment Satisfaction. The impact of type of pretreatment variables on TS was examined by ANOVA at baseline and week 26. Satisfaction at week 26 was examined by t-test and effect size. Linear regression models examined impact of prior treatment factors (age, gender, duration of diabetes, type of prior treatment and diabetes-related comorbidities) and current treatment factors (weight gain, hypoglycemic events, reaching therapeutic goal) on TS. Results: The data set comprised 17,488 persons. Prior treatment with insulin had a more positive impact on baseline satisfaction. At week 26, there were no differences between type of prior treatment groups in Overall, Symptoms and Burden TS. Current treatment with NovoMix 30 significantly improved TS. Regression analyses examining the combined effect of pretreatment factors and current treatment factors found that all factors except for age-impacted TS although the domains impacted varied. Conclusions: Patients treated with NovoMix 30 reported improved treatment satisfaction, and the improvement is considered clinically meaningful to patients. © 2010 The Author(s).