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result(s) for
"Lopez-Colon, Dalia"
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β1‐receptor polymorphisms and junctional ectopic tachycardia in children after cardiac surgery
by
Humma, James F.
,
Dacosta, Jonathan
,
Johnson, Julie A.
in
Adrenergic receptors
,
Adult
,
Arrhythmia
2022
Junctional ectopic tachycardia (JET) is a potentially life‐threatening postoperative arrhythmia in children with specific congenital heart defects and can contribute significantly to postoperative morbidity for at‐risk populations. In adults, β1‐adrenergic receptor (ADRB1) and β2‐adrenergic receptor (ADRB2) genotypes have been associated with increased risk for arrhythmias. However, their association with arrhythmia risk in children is unknown. We aimed to test associations between ADRB1 and ADRB2 genotypes and postoperative JET in patients with congenital heart defects. Children who underwent cardiac surgery were genotyped for the ADRB1 p.Ser49Gly (rs1801252; c.145A>G), p.Arg389Gly (rs1801253; c.1165C>G), ADRB2 p.Arg16Gly (rs1042713; c.46A>G), and p.Glu27Gln (rs1042714; c.79G>C) polymorphisms. The occurrence of postoperative JET was assessed via cardiologist‐interpreted electrocardiograms. Genotype associations with JET were analyzed via logistic regression, adjusted for clinical variables associated with JET, with separate analysis in patients not on a β‐blocker. Of the 343 children included (median age 8 months, 53% boys, 69% European ancestry), 45 (13%) developed JET. The Arg389Arg genotype was not significantly associated with JET in the overall population (odds ratio [OR] = 1.96, 95% confidence interval [CI] = 0.96–4.03, p = 0.064), but was nominally associated in patients not taking a β‐blocker (n = 324, OR = 2.25, 95% CI = 1.05–4.80. p = 0.034). None of the other variants were associated with JET. These data suggest that the ADRB1 Arg389Arg genotype may predict risk for JET following cardiac surgery in pediatric patients in the absence of β‐blockade. Whether treatment with a β‐blocker ameliorates this association requires further research.
Journal Article
Generation of Lung Adenocarcinoma DNA Aptamers for Cancer Studies
by
Chen, Hui William
,
Tockman, Melvyn S.
,
Jiménez, Elizabeth
in
Adenocarcinoma
,
Adenocarcinoma - genetics
,
Adenocarcinoma of Lung
2012
Lung cancer is the most lethal malignancy in the world, and each year thousands of people die from this disease. Early detection has proven to increase the 5-year survival for this cancer in general, independent of the origination site in the lung. To address this challenge, we have used cell-based SELEX (Systematic Evolution of Ligands by Exponential Enrichment) to select a panel of aptamers capable of distinguishing lung adenocarcinoma cells from normal lung epithelial cells. These aptamers bind at physiological and formalin-fixed conditions and display affinity for their targets with apparent K(d')s in the nanomolar range. Our findings suggest that the selected aptamers have the potential to be used in clinical settings, as well as to improve classification of nonsurgical specimens, another current challenge in lung cancer.
Journal Article
DNA Aptamers as Molecular Probes for Colorectal Cancer Study
2010
Understanding the molecular features of specific tumors can increase our knowledge about the mechanism(s) underlying disease development and progression. This is particularly significant for colorectal cancer, which is a heterogeneous complex of diseases developed in a sequential manner through a multistep carcinogenic process. As such, it is likely that tumors with similar characteristics might originate in the same manner and have a similar molecular behavior. Therefore, specific mapping of the molecular features can be potentially useful for both tumor classification and the development of appropriate therapeutic regimens. However, this can only be accomplished by developing high-affinity molecular probes with the ability to recognize specific markers associated with different tumors. Aptamers can most easily meet this challenge based on their target diversity, flexible manipulation and ease of development.
Using a method known as cell-based Systematic Evolution of Ligands by Exponential enrichment (cell-SELEX) and colorectal cancer cultured cell lines DLD-1 and HCT 116, we selected a panel of target-specific aptamers. Binding studies by flow cytometry and confocal microscopy showed that these aptamers have high affinity and selectivity. Our data further show that these aptamers neither recognize normal colon cells (cultured and fresh), nor do they recognize most other cancer cell lines tested.
The selected aptamers can identify specific biomarkers associated with colorectal cancers. We believe that these probes could be further developed for early disease detection, as well as prognostic markers, of colorectal cancers.
Journal Article
Molecular recognition of acute myeloid leukemia using aptamers
by
Sefah, K
,
Martin, J
,
Meng, L
in
Acids
,
Acute myeloid leukemia
,
Antigens, Neoplasm - metabolism
2009
Cell surface proteins can play important roles in cancer pathogenesis. Comprehensive understanding of the surface protein expression patterns of tumor cells and, consequently, the pathogenesis of tumor cells depends on molecular probes against these proteins. To be used effectively for tumor diagnosis, classification and therapy, such probes would be capable of specific binding to targeted tumor cells. Molecular aptamers, designer DNA–RNA probes, can address this challenge by recognizing proteins, peptides and other small molecules with high affinity and specificity. Through a process known as cell-based SELEX, we used live acute myeloid leukemia (AML) cells to select a group of DNA aptamers, which can recognize AML cells with dissociation constants (Kd's) in the nanomolar range. Interestingly, one aptamer (KH1C12) compared with two control cell lines (K562 and NB4) showed significant selectivity to the target AML cell line (HL60) and could recognize the target cells within a complex mixture of normal bone marrow aspirates. The other two aptamers KK1B10 and KK1D04 recognize targets associated with monocytic differentiation. Our studies show that the selected aptamers can be used as a molecular tool for further understanding surface protein expression patterns on tumor cells and thus providing a foundation for effective molecular analysis of leukemia and its subcategories.
Journal Article
Elevated Aortic Stiffness after Pediatric Heart Transplantation
by
Vyas, Himesh V.
,
Gupta, Dipankar
,
Coppola, John-Anthony
in
Adolescent
,
Aorta - diagnostic imaging
,
Aorta - physiopathology
2024
In adults, arterial stiffness has been linked to the development of target end-organ damage, thought to be related to abnormal transmission of pulse pressure. Increased arterial stiffness and endothelial dysfunction have been hypothesized to contribute to the development of microvascular dysfunction and coronary allograft vasculopathy (CAV), an important comorbidity after heart transplantation. However, little data exists regarding arterial stiffness in pediatric heart transplantation and its influence on development of coronary allograft vasculopathy is not well understood. We sought to assess aortic stiffness and distensibility in pediatric post-heart transplant patients. A prospective, observational study analyzing the ascending (donor tissue) and descending aorta (recipient tissue) using transthoracic echocardiographic M-mode measurements in patients aged < 21 years was conducted. Descending and ascending aorta M-modes were obtained from the subcostal long axis view, and the parasternal long axis view 3–5mm above the sinotubular junction, respectively. Two independent reviewers averaged measurements over 2–3 cardiac cycles, and Aortic Distensibility (AD) and Aortic Stiffness Index (ASI) were calculated using previously validated methods. We recruited 39 heart transplant (HT) patients and 47 healthy controls. Median end diastolic dimension of the ascending aorta (donor tissue) was significantly larger in the transplant group than the control group (1.92 cm vs. 1.74 cm,
p
= 0.01). Ascending aortic distensibility in post-transplant patients was significantly lower than in the control group (4.87 vs. 10.53,
p
< 0.001). Ascending aortic stiffness index was higher in the transplant patients compared to the controls (4.63 vs. 2.21,
p
< 0.001). There is evidence of altered ascending aortic distensibility and stiffness parameters in post-heart transplant patients. Further studies are required to assess its influence on complications like development of coronary artery vasculopathy.
Journal Article
Study of the Molecular Recognition of Aptamers Selected through Ovarian Cancer Cell-SELEX
by
Sefah, Kwame
,
Sutphen, Rebecca
,
López-Colón, Dalia
in
Aptamers
,
Aptamers, Nucleotide - genetics
,
Aptamers, Nucleotide - metabolism
2010
Ovarian cancer is the most lethal gynecological malignancy, and the ovarian clear cell carcinoma subtype (OCCA) demonstrates a particularly poor response to standard treatment. Improvements in ovarian cancer outcomes, especially for OCCA, could be expected from a clearer understanding of the molecular pathology that might guide strategies for earlier diagnosis and more effective treatment.
Cell-SELEX technology was employed to develop new molecular probes for ovarian cancer cell surface markers. A total of thirteen aptamers with K(d)'s to ovarian cancer cells in the pico- to nanomolar range were obtained. Preliminary investigation of the targets of these aptamers and their binding characteristics was also performed.
We have selected a series of aptamers that bind to different types of ovarian cancer, but not cervical cancer. Though binding to other cancer cell lines was observed, these aptamers could lead to identification of biomarkers that are related to cancer.
Journal Article
A single centre experience with an evolving approach for the repair of coarctation of the aorta
by
Philip, Joseph
,
Chandran, Arun
,
Costopoulos, Kelly
in
Anastomosis
,
Anastomosis, Surgical
,
Angioplasty
2019
Isolated coarctation of the aorta can be repaired by either lateral thoracotomy or sternotomy approach with end-to-end anastomosis. Most commonly, neonates with coarctation of the aorta also have hypoplasia of the arch, requiring median sternotomy and extended end-to-side anastomosis with arch augmentation. The aim of this study was to describe our experience as the institution adopted the median sternotomy approach for repair, by reviewing complications, mortality, and reintervention.
Retrospective chart review of 66 patients aged 0-1 year who had arch repair performed by a single surgeon over an 8-year period was performed. Median age at surgery was 22 days (4-232) and median weight was 3.08 kg (1.25-8.0). Forty-one (62%) patients underwent median sternotomy.
There was 1 death from a noncardiac cause. Eighteen per cent of our patients were ≤2.5 kg. Vocal cord paresis occurred in 16% of patients under 2.5 kg and 9.5% of patients 2.5 kg or above at the time of surgery. Hypertension at 6-month follow-up was greater in patients under 2.5 kg (44%) than patients 2.5 kg or above (15%). Total surgical reintervention rate was 6%. For patients above 2.5 kg, the surgical reintervention rate was 5.4% and for patients below 2.5 kg, the surgical reintervention rate was 8.3%.
We concluded that for neonates with coarctation of the aorta and hypoplastic arch, median sternotomy is a safe surgical approach with low morbidity and mortality with the possible advantage of reduced surgical re-intervention and mortality in the population below 2.5 kg.
Journal Article
Effects of Inlet Geometry on Perfusion and Ischemia in Anomalous Aortic Origin of the Right Coronary Artery (AAORCA)
by
Chandran, Arun
,
Moguillansky, Diego
,
Lopez-Colon, Dalia
in
Boundary conditions
,
Cardiac/Thoracic/Vascular Surgery
,
Cardiology
2024
Anomalous aortic origin of a coronary artery (AAOCA) comprises a set of rare congenital abnormalities in the origin or path of the coronary arteries with highly variable clinical implications. This is a pilot feasibility study where we investigated the influence of the anomalous coronary artery inlet architecture on coronary perfusion using coronary blood flow computational simulations to help predict the risk for coronary ischemia in patients with anomalous aortic origin of the right coronary artery (AAORCA) with these types of anomalous coronary artery inlet architectures. We developed a protocol for generating 3D models of patient coronary artery anatomies from an IRB-approved dataset of cardiac CT images of patients with AAORCA at our institution. Coronary blood flow simulations and analysis were performed. Instantaneous flow reserve (iFR), a parameter used clinically in coronary CT analysis to determine risk for ischemia, was compared between models as a measure of ischemia. Comparing the median iFR of the coronary outlets between the four inlet variants and baseline architecture showed important differences. We observed a possible association between the proportion of the semi-minor axis and the semi-major axis of the elliptical AAORCA inlet and iFR. These observations suggest that the elliptical axis quotient may be a significant risk factor for evaluation of AAORCA severity.
Journal Article
Risk factors associated with post-transplant superior caval vein stenosis in paediatric heart transplantation
by
Whelihan, Joseph T.
,
Gupta, Dipankar
,
Tadros, Hanna J.
in
Anastomosis
,
Aortic stenosis
,
Body mass index
2021
Superior caval vein stenosis is a known complication following paediatric heart transplantation. Herein, we sought to assess the incidence of superior caval vein stenosis and need for intervention in a single centre paediatric heart transplantation programme. A retrospective review was performed to identify variables associated with superior caval vein stenosis and need for intervention. Patients were identified based on angiographic and echocardiographic signs of superior caval vein stenosis. Of 204 paediatric heart transplantation recipients, 49 (24.0%) had evidence of superior caval vein stenosis with no need for catheter intervention and 12 (5.9%) had superior caval vein stenosis requiring catheter intervention. Overall, patients with superior caval vein stenosis with and without intervention had more cavopulmonary anastomosis (41.7%; 20.4%), pre-transplant superior caval vein procedures (41.7%; 28.6%), and bicaval approach (100.0%; 98.0%), compared to the group with no stenosis (11.9% and p = 0.015, 12.6% and p = 0.004, 73.4% and p < 0.001, respectively). Smaller recipients and donors were more likely to need intervention. Intervention was also seen more frequently in recipients who were younger at diagnosis (4.7 years) compared to non-intervention (13.3 years; p = 0.040). Re-intervention was required in 16.7% patients (n = 2) and was not associated with any complications.
Journal Article
End-organ recovery post-ventricular assist device can prognosticate survival
by
Philip, Joseph
,
Fricker, Frederick J.
,
Lopez-Colon, Dalia
in
Adolescent
,
Adult
,
Analysis of Variance
2018
This study examines our institutional ventricular assist devices (VADs) experience over two decades to understand trends towards predictors of mortality.
Retrospective study of patients aged 0–21years supported with a VAD from January 1996 to May 2015. Patient data was examined pre and post-VAD implant among survivors and non-survivors.
Thirty-six patients identified (8 supported by Thoratec® VAD and 28 supported by EXCOR Berlin Heart®). Patient's diagnosis included dilated cardiomyopathy (DCM) (n=19,53%), congenital heart disease (CHD) (n=12,33%), and other (n=5,14%). Median age and body surface area (BSA) were 1.0years[0–7years] and 0.41[0.24–0.92], respectively. Survival to discharge was 75% with no deaths with DCM. The survival rate for patients with CHD was 42%. Univariate analysis showed diagnosis of CHD, smaller BSA and respiratory failure post-implant (Intermacs criteria) as risk factors for mortality. Median duration of VAD support was lower in non-survivors, 14 vs 63days (p=0.03). Renal function at time of transplant or death was normal/pRIFLE Risk category in 20(74%) of survivors and 2(22%) of non-survivors (p=0.06). Post-implant, peak total bilirubin in the first week trended lower in survivors (p=0.06).
Persistent end-organ impairment in the first 2weeks after VAD placement could be a useful prognostic marker for survival to transplant.
•Etiology of heart failure is a key determinant in VAD survival.•Post-VAD complications were similar between survivors and non-survivors in this predominantly BiVAD subset.•Persistent end-organ impairment in the first 2weeks after VAD placement could be a useful prognostic marker.•Among the 13 patients in renal failure (pRIFLE), the longest need for RRT in a survivor was 22days post-VAD placement.
Journal Article