Publications by authors named "Omar Sultan"

20 Publications

  • Page 1 of 1

Canadian national electrophysiology ablation registry report 2011-2016.

BMC Health Serv Res 2021 May 6;21(1):435. Epub 2021 May 6.

Sunnybrook Health Sciences Centre, University of Toronto, 890 Sheppard Avenue West, Ontario, M4N 3M5, Toronto, Canada.

Background/purpose: Interventional cardiac electrophysiology (EP) is a rapidly evolving field in Canada; a nationwide registry was established in 2011 to conduct a periodic review of resource allocation.

Methods: The registry collects annual data on EP lab infrastructure, imaging, tools, human resources, procedural volumes, success rates, and wait times. Leading physicians from each EP lab were contacted electronically; participation was voluntary.

Results: All Canadian EP centres were identified (n = 30); 50 and 45 % of active centres participated in the last 2 instalments of the registry. A mean of 508 ± 270 standard and complex catheter ablation procedures were reported annually for 2015-2016 by all responding centres. The most frequently performed ablation targets atrial fibrillation (PVI) arrhythmia accounting for 36 % of all procedures (mean = 164 ± 85). The number of full time physicians ranges between 1 and 7 per centre, (mean = 4). The mean wait time to see an electrophysiologist for an initial non-urgent consult is 23 weeks. The wait time between an EP consult and ablation date is 17.8 weeks for simple ablation, and 30.1 weeks for AF ablation. On average centres have 2 (range: 1-4) rooms equipped for ablations; each centre uses the EP lab an average of 7 shifts per week. While diagnostic studies and radiofrequency ablations are performed in all centres, point-by-point cryoablation is available in 85 % centres; 38 % of the respondents use circular ablation techniques.

Conclusions: This initiative provides contemporary data on invasive electrophysiology lab practices. The EP registry provides activity benchmarks on national trends and practices.
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http://dx.doi.org/10.1186/s12913-021-06441-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8101210PMC
May 2021

Intra-articular Synovial Hemangioma: A Rare Cause of Knee Pain and Swelling.

J Clin Imaging Sci 2021 26;11:26. Epub 2021 Apr 26.

Department of Radiology, College of Medicine, Tikrit University, Tikrit, Saladain, Iraq.

Synovial hemangioma is a rare intra articular lesion and it has several more common differentials. Therefore, our main objective is to consider the possibility of hemangioma in any intra-articular mass to prevent diagnostic delay of unnoticed or untreated hemangioma occurring within the knee joint. Ultrasound can be useful method in assessing the lesions. Surgical excision is the definitive treatment for such lesions.
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http://dx.doi.org/10.25259/JCIS_129_2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8088478PMC
April 2021

Comparison of plantar loading patterns on natural grass and artificial turf during various athletic activities.

J Sports Med Phys Fitness 2021 May 20;61(5):680-686. Epub 2021 Jan 20.

Department of Physical Therapy, College of Applied Medical Sciences, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia.

Background: This study aimed to investigate the differences in plantar pressure during various athletic activities on natural grass and artificial turf.

Methods: Twenty-one athletes were fitted with properly sized soccer shoes and corresponding F-Scan system insoles and performed walking, running, vertical jumping and cutting activities to the right and left sides on both natural and artificial turf.

Results: There were no statistically significant differences between natural grass and artificial turf in peak pressure, maximum force and force-time integral during all the athletic activities (P˃0.05). On both turfs, the highest peak pressure and maximum force values occurred during running and cutting to the right, and the highest force-time integral value occurred during cutting to the right. There were no statistically significant differences between the two turfs in peak pressure in the various anatomical regions during any of the athletic activities (P˃0.05). The peak pressure was the highest on the first metatarsal and the hallux during all five activities. A clinically meaningful difference between the surfaces in peak pressure on the second to fifth metatarsals was found during walking, indicating more loading on artificial turf than on natural grass. There was more loading on artificial turf than on natural grass during cutting left and at hallux and third toe on natural grass during cutting right. However, these differences were not statistically significant (P˃0.05).

Conclusions: The results of this study suggest that it is important to limit or prevent athletes from undertaking certain activities that increase the risk of re-injury during rehabilitation.
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http://dx.doi.org/10.23736/S0022-4707.21.11342-8DOI Listing
May 2021

Association of uterine and urinary bladder lipomas.

J Clin Ultrasound 2021 Jan 18. Epub 2021 Jan 18.

Faculty of Medicine, University of Kufa, Kufa, Iraq.

Lipomas of the uterus and of the urinary bladder are rare. Their coexistence is even rarer Ultrasound can play a key role in their diagnosis. We report a case of coexisting of the uterus and the urinary bladder in a 61-year-old woman.
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http://dx.doi.org/10.1002/jcu.22976DOI Listing
January 2021

Age-Related Pattern and Distribution of Covid-19 on Pulmonary Computed Tomography.

Curr Med Imaging 2020 Dec 23. Epub 2020 Dec 23.

Department of Radiology, Al-Yarmuk Teaching Hospital, Baghdad 10001. Iraq.

Background: COVID-19 has emerged recently and become of global concern. Computed tomography (CT) plays a vital role in the diagnosis.

Objectives: To characterize the pulmonary CT changes and distributions of COVID-19 infection in regard to different age groups.

Methods: Chest CT scan of 104 symptomatic patients with COVID-19 infection, from 7 Iraqi isolation centers were retrospectively analyzed between March 10th and April 5th, 2020. Patients were sub-classified according to their ages to three groups (young adult:20-39years, middle age:40-59years and old age:60- 90years).

Results: The most common findings were ground-glass opacities (GGO) (92.3%, followed by consolidation (27.9%), bronchovascular thickening (15.4%), and crazy-paving (12.5%). Less commonly, there were tree-inbud (6.7%), pulmonary nodules (5.8%), bronchiectasis (3.8%), pleural effusion (1.9%), and cavitation (1%). There were no hallo sign, reversed hallo sign, nor mediastinal lymphadenopathy. Pulmonary changes were unilateral in 16.7% and bilateral in 83.3%, central in 14.6%, peripheral in 57.3%, and diffuse (central and peripheral) in 28.1%. Most cases showed multi-lobar changes (70.8%), while the lower lobe was more commonly involved (17.7%) than middle lobe/lingula (8.3%) and upper lobe (3.1%). In unilateral involvement, changes were more on the right (68.8%) than left (31.2%) side. Compared with middle and old age groups, young adult patients showed significantly lesser frequency of consolidation (17% vs. 13.3% and 37%), diffuse changes 28.1% (14.2% vs. 35.3% and 40.5%), bilateral disease (71.4% vs. 94.1% and 85.2%), and multi-lobar involvement (51.4% vs. 82.4% and 81.4%) respectively.

Conclusion: Bilateral and peripheral GGO were the most frequent findings with the right side and lower lobar predilection. Extent and pattern seem to be age-related.
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http://dx.doi.org/10.2174/1573405616666201223144539DOI Listing
December 2020

Risk Factors for Infections Involving Cardiac Implanted Electronic Devices.

J Am Coll Cardiol 2019 12;74(23):2845-2854

Department of Medicine, University of Toronto, Division of Cardiology, St. Michael Hospital, Toronto, Ontario, Canada.

Background: Cardiac implantable electronic device infection is a major complication that usually requires device removal. PADIT (Prevention of Arrhythmia Device Infection Trial) was a large cluster crossover trial of conventional versus incremental antibiotics.

Objectives: This study sought to investigate independent predictors of device infection in PADIT and develop a novel infection risk score.

Methods: In brief, over 4 6-month periods, 28 centers used either conventional or incremental prophylactic antibiotic treatment in all patients. The primary outcome was hospitalization for device infection within 1 year (blinded endpoint adjudication). Multivariable logistic prediction modeling was used to identify the independent predictors and develop a risk score for device infection. The prediction models were internally validated with bootstrap methods.

Results: Device procedures were performed in 19,603 patients, and hospitalization for infection occurred in 177 (0.90%) within 1 year of follow-up. The final prediction model identified 5 independent predictors of device infection (prior procedures [P], age [A], depressed renal function [D], immunocompromised [I], and procedure type [T]) with an optimism-corrected C-statistic of 0.704 (95% confidence interval: 0.660 to 0.744). A PADIT risk score ranging from 0 to 15 points classified patients into low (0 to 4), intermediate (5 to 6) and high (≥7) risk groups with rates of hospitalization for infection of 0.51%, 1.42%, and 3.41%, respectively.

Conclusions: This study identified 5 independent predictors of device infection and developed a novel infection risk score in the largest cardiac implantable electronic device trial to date, warranting validation in an independent cohort. The 5 independent predictors in the PADIT score are readily adopted into clinical practice. (Prevention of Arrhythmia Device Infection Trial [PADIT Pilot]; NCT01002911).
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http://dx.doi.org/10.1016/j.jacc.2019.09.060DOI Listing
December 2019

Challenge and Impact of Quinidine Access in Sudden Death Syndromes: A National Experience.

JACC Clin Electrophysiol 2019 03 28;5(3):376-382. Epub 2018 Nov 28.

University of British Columbia, Vancouver, British Columbia, Canada. Electronic address:

Objectives: This study sought to determine the nature of quinidine use and accessibility in a national network of inherited arrhythmia clinics.

Background: Quinidine is an antiarrhythmic medication that has been shown to be beneficial in select patients with Brugada syndrome, early repolarization syndrome, and idiopathic ventricular fibrillation. Because of the low prevalence of these conditions and restricted access to quinidine through a single regulatory process, quinidine use is rare in Canada.

Methods: Subjects prescribed quinidine were identified through the Hearts in Rhythm Organization that connects the network of inherited arrhythmia clinics across Canada. Cases were retrospectively reviewed for patient characteristics, indications for quinidine use, rate of recurrent ventricular arrhythmia, and issues with quinidine accessibility.

Results: In a population of 36 million, 46 patients are currently prescribed quinidine (0.0000013%, age 48.1 ± 16.1 years, 25 are male). Brugada syndrome, early repolarization syndrome, and idiopathic ventricular fibrillation constituted a diagnosis in 13 subjects (28%), 6 (13%), and 21 (46%), respectively. Overall, 37 subjects (81%) had cardiac arrest as an index event. After initial presentation, subjects experienced 7.47 ± 12.3 implantable cardioverter-defibrillator shocks prior to quinidine use over 34.3 ± 45.9 months, versus 0.86 ± 1.69 implantable cardioverter-defibrillator shocks in 43.8 ± 41.8 months while on quinidine (risk ratio: 8.7, p < 0.001). Twenty-two patients access quinidine through routes external to Health Canada's Special Access Program.

Conclusions: Quinidine use is rare in Canada, but it is associated with a reduction in recurrent ventricular arrhythmias in patients with Brugada syndrome, early repolarization syndrome, and idiopathic ventricular fibrillation, with minimal toxicity necessitating discontinuation. Drug interruption is associated with frequent breakthrough events. Access to quinidine is important to deliver this potentially lifesaving therapy.
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http://dx.doi.org/10.1016/j.jacep.2018.10.007DOI Listing
March 2019

Prevention of Arrhythmia Device Infection Trial: The PADIT Trial.

J Am Coll Cardiol 2018 12;72(24):3098-3109

Division of Cardiology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada.

Background: Infection of implanted medical devices has catastrophic consequences. For cardiac rhythm devices, pre-procedural cefazolin is standard prophylaxis but does not protect against methicillin-resistant gram-positive organisms, which are common pathogens in device infections.

Objective: This study tested the clinical effectiveness of incremental perioperative antibiotics to reduce device infection.

Methods: The authors performed a cluster randomized crossover trial with 4 randomly assigned 6-month periods, during which centers used either conventional or incremental periprocedural antibiotics for all cardiac implantable electronic device procedures as standard procedure. Conventional treatment was pre-procedural cefazolin infusion. Incremental treatment was pre-procedural cefazolin plus vancomycin, intraprocedural bacitracin pocket wash, and 2-day post-procedural oral cephalexin. The primary outcome was 1-year hospitalization for device infection in the high-risk group, analyzed by hierarchical logistic regression modeling, adjusting for random cluster and cluster-period effects.

Results: Device procedures were performed in 28 centers in 19,603 patients, of whom 12,842 were high risk. Infection occurred in 99 patients (1.03%) receiving conventional treatment, and in 78 (0.78%) receiving incremental treatment (odds ratio: 0.77; 95% confidence interval: 0.56 to 1.05; p = 0.10). In high-risk patients, hospitalization for infection occurred in 77 patients (1.23%) receiving conventional antibiotics and in 66 (1.01%) receiving incremental antibiotics (odds ratio: 0.82; 95% confidence interval: 0.59 to 1.15; p = 0.26). Subgroup analysis did not identify relevant patient or site characteristics with significant benefit from incremental therapy.

Conclusions: The cluster crossover design efficiently tested clinical effectiveness of incremental antibiotics to reduce device infection. Device infection rates were low. The observed difference in infection rates was not statistically significant. (Prevention of Arrhythmia Device Infection Trial [PADIT Pilot] [PADIT]; NCT01002911).
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http://dx.doi.org/10.1016/j.jacc.2018.09.068DOI Listing
December 2018

Renal anomalies in patients with turner syndrome: Is scintigraphy superior to ultrasound?

Am J Med Genet A 2016 Feb 30;170A(2):355-362. Epub 2015 Nov 30.

Departments of Radiodiagnosis and Diagnostic Nuclear Medicine, Faculty of Medicine, Ain Shams University, Cairo, Egypt.

Renal anomalies are present in up to 30% of patients with Turner syndrome (TS). Renal ultrasound (U/S) detects anatomical renal anomalies only while renal scintigraphy detects anomalies, detects early renal malfunction, and estimates glomerular filtration rate (GFR). Thus, we aimed to assess frequency of renal abnormalities detected by scintigraphy in comparison to renal U/S in TS patients. Ninety TS patients were subjected to auxological assessment, measurement of serum creatinine; and renal U/S and scintigraphy. Renal U/S detected renal anomalies in 22.22% of patients versus 17.78 % detected by scintigraphy (P = 0.035). Scintigraphy detected renal functional abnormalities in 44.44% of patients in the form of subnormal total GFR, abnormal renogram curve pattern, improper tracer handling and perfusion; and difference in split renal function >10% between both kidneys. Patients with a 45,X karyotype had more renal functional abnormalities (56%) than those with mosaic karyotype (33.33%), P = 0.04. In conclusion, renal scintigraphy is not superior to U/S in detection of renal anomalies but is a reliable method for early detection of renal malfunction in TS patients especially those with 45,X to ensure early management to offer a better quality of life.
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http://dx.doi.org/10.1002/ajmg.a.37425DOI Listing
February 2016

Conjoined twins-thoraco-omphalopagus (type A).

BJR Case Rep 2016 22;2(1):20150016. Epub 2015 Oct 22.

A case of conjoined twins discovered by routine transabdominal ultrasound examination at 16 weeks gestation in a 19-year-old multigravid female. They were joined at the chest and the abdomen and had one functional heart. The pregnancy was terminated by caesarean section at 19 weeks gestation with approval from the family.
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http://dx.doi.org/10.1259/bjrcr.20150016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6195922PMC
October 2015

Snapshot of adult invasive cardiac electrophysiology in Canada: results of the web-based registry.

J Interv Card Electrophysiol 2014 Jun 22;40(1):93-8. Epub 2014 Apr 22.

Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada,

Purpose: Interventional cardiac electrophysiology (EP) has experienced a significant growth in Canada. Our aim is to establish a periodic registry as a nationwide initiative.

Methods: The registry is designed to collect information regarding EP laboratory infrastructure, human resources, and the spectrum and volumes of EP procedures. Respective administrative staff were contacted electronically.

Results: Out of 25 identified Canadian EP centers, 19 centers (76%) have participated in the registry. Responding centers have access on average to 5.3 lab days per week to perform EP studies/ablations; average lab time per full- and part-time (prorated to 0.5) EP physician is 0.8 day per week. Diagnostic EP studies and radio-frequency ablations are performed in all (19) centers; cryoablation is available in 83% of centers. Two centers have remote magnetic navigation systems. EnSite NavX is the most widely available 3D mapping system utilized in 15 (83%) centers, followed by CARTO and intracardiac echo which are each available in 14 (78%) centers; LocaLisa is actively used in one center. The number of full-time physicians ranges between 0 and 7, with a mean of 3.5 full-time physicians per center. The ratio of staff to trainees is 1.6:1. A total of 8,041 EP procedures are performed in the 19 centers per annum. On an annual average, 104 procedures per one operator and 159 procedures per trainee are performed.

Conclusions: This registry provides contemporary information on invasive EP lab resources and procedures in Canada. It also demonstrates that Canadian EP procedural intensities of practice and training are comparable to international standards.
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http://dx.doi.org/10.1007/s10840-014-9899-6DOI Listing
June 2014

Top-down proteomic identification of Shiga toxin 2 subtypes from Shiga toxin-producing Escherichia coli by matrix-assisted laser desorption ionization-tandem time of flight mass spectrometry.

Appl Environ Microbiol 2014 May 28;80(9):2928-40. Epub 2014 Feb 28.

Produce Safety Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, California, USA.

We have analyzed 26 Shiga toxin-producing Escherichia coli (STEC) strains for Shiga toxin 2 (Stx2) production using matrix-assisted laser desorption ionization (MALDI)-tandem time of flight (TOF-TOF) tandem mass spectrometry (MS/MS) and top-down proteomic analysis. STEC strains were induced to overexpress Stx2 by overnight culturing on solid agar supplemented with either ciprofloxacin or mitomycin C. Harvested cells were lysed by bead beating, and unfractionated bacterial cell lysates were ionized by MALDI. The A2 fragment of the A subunit and the mature B subunit of Stx2 were analyzed by MS/MS. Sequence-specific fragment ions were used to identify amino acid subtypes of Stx2 using top-down proteomic analysis using software developed in-house at the U.S. Department of Agriculture (USDA). Stx2 subtypes (a, c, d, f, and g) were identified on the basis of the mass of the A2 fragment and the B subunit as well as from their sequence-specific fragment ions by MS/MS (postsource decay). Top-down proteomic identification was in agreement with DNA sequencing of the full Stx2 operon (stx2) for all strains. Top-down results were also compared to a bioassay using a Vero-d2EGFP cell line. Our results suggest that top-down proteomic identification is a rapid, highly specific technique for distinguishing Stx2 subtypes.
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http://dx.doi.org/10.1128/AEM.04058-13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3993300PMC
May 2014

Possible evidence of amide bond formation between sinapinic acid and lysine-containing bacterial proteins by matrix-assisted laser desorption/ionization (MALDI) at 355 nm.

J Am Soc Mass Spectrom 2012 Dec 2;23(12):2102-14. Epub 2012 Oct 2.

Agricultural Research Service, US Department of Agriculture, Western Regional Research Center, 800 Buchanan Street, Albany, CA 94710, USA.

We previously reported the apparent formation of matrix adducts of 3,5-dimethoxy-4-hydroxy-cinnamic acid (sinapinic acid or SA) via covalent attachment to disulfide bond-containing proteins (HdeA, Hde, and YbgS) from bacterial cell lysates ionized by matrix-assisted laser desorption/ionization (MALDI) time-of-flight-time-of-flight tandem mass spectrometry (TOF-TOF-MS/MS) and post-source decay (PSD). We also reported the absence of adduct formation when using α-cyano-4-hydroxycinnamic acid (CHCA) matrix. Further mass spectrometric analysis of disulfide-intact and disulfide-reduced over-expressed HdeA and HdeB proteins from lysates of gene-inserted E. coli plasmids suggests covalent attachment of SA occurs not at cysteine residues but at lysine residues. In this revised hypothesis, the attachment of SA is preceded by formation of a solid phase ammonium carboxylate salt between SA and accessible lysine residues of the protein during sample preparation under acidic conditions. Laser irradiation at 355 nm of the dried sample spot results in equilibrium retrogradation followed by nucleophilic attack by the amine group of lysine at the carbonyl group of SA and subsequent amide bond formation and loss of water. The absence of CHCA adducts suggests that the electron-withdrawing effect of the α-cyano group of this matrix may inhibit salt formation and/or amide bond formation. This revised hypothesis is supported by dissociative loss of SA (-224 Da) and the amide-bound SA (-206 Da) from SA-adducted HdeA and HdeB ions by MS/MS (PSD). It is proposed that cleavage of the amide-bound SA from the lysine side-chain occurs via rearrangement involving a pentacyclic transition state followed by hydrogen abstraction/migration and loss of 3-(4-hydroxy-3,5-dimethoxyphenyl)prop-2-ynal (-206 Da).
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http://dx.doi.org/10.1007/s13361-012-0490-zDOI Listing
December 2012

A new calibrant for matrix-assisted laser desorption/ionization time-of-flight-time-of-flight post-source decay tandem mass spectrometry of non-digested proteins for top-down proteomic analysis.

Rapid Commun Mass Spectrom 2012 May;26(10):1241-8

Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA 94710, USA.

Rationale: Matrix-assisted laser desorption/ionization (MALDI) time-of-flight-time-of-flight (TOF-TOF) post-source decay (PSD) tandem mass spectrometry (MS/MS) has seen increasing use for analysis of non-digested protein ions for top-down proteomic identification. However, there is no commonly accepted calibrant for this purpose beyond the use of peptide calibrants whose fragment ions span a lower mass-to-charge (m/z) range.

Methods: We have used the PSD-generated fragment ions of disulfide-reduced/alkylated thioredoxin (AlkTrx) for TOF-TOF calibration in reflectron mode for the purpose of PSD-MS/MS analysis. The average m/z values of AlkTrx fragment ions were used for calibration. The quality of the calibration was assessed from the observed fragment ion mass error of MS/MS of the YahO protein from an unfractionated bacterial cell lysate of Escherichia coli O157:H7 as well as from MS/MS of bovine ubiquitin. The fragment ion mass errors of these two analytes were also used to assess instrument calibration using the monoisotopic fragment ions of [Glu(1)]-fibrinopeptide B (GluFib).

Results: A general improvement in fragment ion mass accuracy was observed using the AlkTrx calibration compared to the GluFib calibration which resulted in a more significant top-down proteomic identification of these analyte proteins.

Conclusions: Our results suggest that AlkTrx may be useful as a calibrant for MALDI-TOF-TOF-PSD-MS/MS of small and modest-sized protein ions. The uniform fragmentation efficiency of YahO across its sequence suggests that it may be useful as a post-calibration standard to assess PSD-MS/MS instrument performance as well as establishing appropriate top-down proteomic fragment ion tolerances.
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http://dx.doi.org/10.1002/rcm.6220DOI Listing
May 2012

Evolutionary silence of the acid chaperone protein HdeB in enterohemorrhagic Escherichia coli O157:H7.

Appl Environ Microbiol 2012 Feb 16;78(4):1004-14. Epub 2011 Dec 16.

Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, California, USA.

The periplasmic chaperones HdeA and HdeB are known to be important for cell survival at low pH (pH < 3) in Escherichia coli and Shigella spp. Here we investigated the roles of HdeA and HdeB in the survival of various enterohemorrhagic E. coli (EHEC) following exposure to pH 2.0. Similar to K-12 strains, the acid protections conferred by HdeA and HdeB in EHEC O145 were significant: loss of HdeA and HdeB led to over 100- to 1,000-fold reductions in acid survival, depending on the growth condition of prechallenge cells. However, this protection was much less in E. coli O157:H7 strains. Deletion of hdeB did not affect the acid survival of cells, and deletion of hdeA led to less than a 5-fold decrease in survival. Sequence analysis of the hdeAB operon revealed a point mutation at the putative start codon of the hdeB gene in all 26 E. coli O157:H7 strains analyzed, which shifted the ATG start codon to ATA. This mutation correlated with the lack of HdeB in E. coli O157:H7; however, the plasmid-borne O157-hdeB was able to restore partially the acid resistance in an E. coli O145ΔhdeAB mutant, suggesting the potential function of O157-HdeB as an acid chaperone. We conclude that E. coli O157:H7 strains have evolved acid survival strategies independent of the HdeA/B chaperones and are more acid resistant than nonpathogenic K-12 for cells grown under nonfavorable culturing conditions such as in Luria-Bertani no-salt broth at 28°C. These results suggest a divergent evolution of acid resistance mechanisms within E. coli.
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http://dx.doi.org/10.1128/AEM.07033-11DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3273018PMC
February 2012

A polymorphism in the retinol binding protein 4 gene is not associated with gestational diabetes mellitus in several different ethnic groups.

Hawaii Med J 2011 Aug;70(8):164-7

University of Hawai'i, Department of Obstetrics, Gynecology and Women's Health, Honolulu, USA.

Objective: Various Asian and Pacifific Islander groups have higher prevalence rates of type 2 diabetes and gestational diabetes. This increased incidence is likely to include genetic factors. Single nucleotide polymorphisms in the retinol binding protein 4 gene have been linked to the occurrence of type 2 diabetes. Hypothesizing a link between retinol binding protein 4 and gestational diabetes, we performed a candidate gene study to look for an association between an important retinol binding protein gene polymorphism (rs3758539) and gestational diabetes.

Study Design: Blood was collected from Caucasian, Asian, and Pacific Islander women diagnosed with gestational diabetes and from ethnically matched non-diabetic controls. DNA was extracted and real time PCR technology (TaqMan, Applied Biosystems) used to screen for the rs3758539 single nucleotide polymorphism located 5' of exon 1 of the retinol binding protein 4 gene.

Results: Genotype and allele frequencies in the controls and gestational diabetes cases were tested using chi-square contingency tests. Genotype frequencies were in Hardy-Weinberg equilibrium. There was no association between the rs3758539 retinol binding protein 4 single nucleotide polymorphism and gestational diabetes in the Caucasian, Filipino, or Pacific Islander groups.

Conclusion: Interestingly, the rs3758539 retinol binding protein 4 single nucleotide polymorphism was not found to be associated with gestational diabetes. The absence of association suggests that gestational and type 2 diabetes may have more divergent molecular pathophysiology than previously suspected.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3158378PMC
August 2011

O serogroup specific real time PCR assays for the detection and identification of nine clinically relevant non-O157 STECs.

Food Microbiol 2011 May 27;28(3):478-83. Epub 2010 Oct 27.

U.S. Food and Drug Administration, San Francisco District Laboratory, 1431 Harbor Bay Parkway, Alameda, CA 94502, USA.

TaqMan™ real time PCR assays were designed for each of the non-O157 STEC O serogroups most commonly associated with human illness: O26, O45, O91, O103, O111, O113, O121, O128, and O145. The nine RT-PCR assays can be run as single assays when a known pathogen is of concern, or multiplexed in three reactions, to quickly screen for the most clinically relevant O serogroups. All assays included an internal amplification control constructed from the green fluorescent protein gene as an indicator of PCR inhibition. Of 103 strains tested, the inclusive tests accurately identified the O serogroup for 101 strains. The exclusive tests for each assay yielded no false positives for over 120 Escherichia coli strains and 23 non-E. coli bacteria tested. Furthermore, the RT-PCR assays were tested by inoculating four food matrices, milk, apple juice, lettuce, and ground beef, at ≤30 CFU/25 g or mL. Following a 24h selective enrichment, the RT-PCR assays detected STECs in all foods except for one ground beef sample inoculated with O111, and all apple juice samples inoculated with O113. The assays could also detect each O serogroup in human stool specimens inoculated with STECs at 1000 CFU/0.5 g of stool following 24 h enrichment.
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http://dx.doi.org/10.1016/j.fm.2010.10.007DOI Listing
May 2011

Induction and identification of disulfide-intact and disulfide-reduced β-subunit of Shiga toxin 2 from Escherichia coli O157:H7 using MALDI-TOF-TOF-MS/MS and top-down proteomics.

Analyst 2011 Apr 21;136(8):1739-46. Epub 2011 Feb 21.

Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 800 Buchanan Street, Albany, CA 94710, USA.

The disulfide-intact and disulfide-reduced β-subunit of Shiga toxin 2 (β-Stx2) from Escherichia coli O157:H7 (strain EDL933) has been identified by matrix-assisted laser desorption/ionization time-of-flight-time-of-flight tandem mass spectrometry (MALDI-TOF-TOF-MS/MS) and top-down proteomic analysis using software developed in-house. E. coli O157:H7 was induced to express Stx2 by culturing on solid agar media supplemented with 10-50 ng mL(-1) of ciprofloxacin (CP). Bacterial cell lysates at each CP concentration were analyzed by MALDI-TOF-MS. A prominent ion at mass-to-charge (m/z) ~7820 was observed for the CP concentration range: 10-50 ng mL(-1), reaching a maximum signal intensity at 20 ng mL(-1). Complex MS/MS data were obtained of the ion at m/z ~7820 by post-source decay resulting in top-down proteomic identification as the mature, signal peptide-removed, disulfide-intact β-Stx2. Eight fragment ion triplets (each spaced Δm/z ~33 apart) were also observed resulting from backbone cleavage between the two cysteine residues (that form the intra-molecular disulfide bond) and symmetric and asymmetric cleavage of the disulfide bond. The middle fragment ion of each triplet, from symmetric disulfide bond cleavage, was matched to an in silico fragment ion formed from cleavage of the backbone at a site adjacent to an aspartic acid or glutamic acid residue. The flanking fragment ions of each triplet, from asymmetric disulfide bond cleavage, were not matched because their corresponding in silico fragment ions are not represented in the database. Easier to interpret MS/MS data were obtained for the disulfide-reduced β-Stx2 which resulted in an improved top-down identification.
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http://dx.doi.org/10.1039/c0an00909aDOI Listing
April 2011

Top-down proteomic identification of furin-cleaved α-subunit of Shiga toxin 2 from Escherichia coli O157:H7 using MALDI-TOF-TOF-MS/MS.

J Biomed Biotechnol 2010 10;2010:123460. Epub 2011 Feb 10.

Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 800 Buchanan Street, Albany, CA 94710, USA.

A method has been developed to identify the α-subunit of Shiga toxin 2 (α-Stx2) from Escherichia coli O157:H7 using matrix-assisted laser desorption/ionization time-of-flight-time-of-flight tandem mass spectrometry (MALDI-TOF-TOF-MS/MS) and top-down proteomics using web-based software developed in-house. Expression of Stx2 was induced by culturing E. coli O157:H7 on solid agar supplemented with an antibiotic that elicits the bacterial SOS-response. Bacterial cell lysates were incubated in the presence of furin, a human enzyme, that cleaves α-Stx2 into A1 (~28 kDa) and A2 (~5 kDa) protein fragments. A subsequent disulfide reduction step unlinked A1 from A2. MALDI-TOF-MS of the furin-digested/disulfide-reduced sample showed a peak at mass-to-charge (m/z) 5286 that corresponded to the A2 fragment. No peak was observed that corresponded to the A1 fragment although its presence was confirmed by bottom-up proteomics. The peak at m/z 5286 was definitively identified by MALDI-TOF-TOF-MS/MS and top-down proteomics as the A2 fragment of α-Stx2.
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http://dx.doi.org/10.1155/2010/123460DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3038467PMC
June 2011

Access to care: the physician's perspective.

Hawaii Med J 2011 Feb;70(2):33-8

Infections Limited Hawaii, Honolulu, Hawaii 96813, USA.

Private practice physicians in Hawaii were surveyed to better understand their impressions of different insurance plans and their willingness to care for patients with those plans. Physician experiences and perspectives were investigated in regard to reimbursement, formulary limitations, pre-authorizations, specialty referrals, responsiveness to problems, and patient knowledge of their plans. The willingness of physicians to accept new patients from specific insurance company programs clearly correlated with the difficulties and limitations physicians perceive in working with the companies (p<0.0012). Survey results indicate that providers in private practice were much more likely to accept University Health Alliance (UHA) and Hawaii Medical Services Association (HMSA) Commercial insurance than Aloha Care Advantage and Aloha Quest. This was likely related to the more favorable impressions of the services, payments, and lower administrative burden offered by those companies compared with others.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3071212PMC
February 2011