Dr. Jonathan  Chan  Od image

Dr. Jonathan Chan Od

477 E Colorado Blvd
Pasadena CA 91101
626 961-1191
Medical School: Other - Unknown
Accepts Medicare: No
Participates In eRX: No
Participates In PQRS: No
Participates In EHR: No
License #: 14864TLG
NPI: 1093123721
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Intervendor consistency and reproducibility of left ventricular 2D global and regional strain with two different high-end ultrasound systems. - European heart journal cardiovascular Imaging
We aimed to assess intervendor agreement of global (GLS) and regional longitudinal strain by vendor-specific software after EACVI/ASE Industry Task Force Standardization Initiatives for Deformation Imaging.Fifty-five patients underwent prospective dataset acquisitions on the same day by the same operator using two commercially available cardiac ultrasound systems (GE Vivid E9 and Philips iE33). GLS and regional peak longitudinal strain were analyzed offline using corresponding vendor-specific software (EchoPAC BT13 and QLAB version 10.3). Absolute mean GLS measurements were similar between the two vendors (GE -17.5 ± 5.2% vs. Philips -18.9 ± 5.1%, P = 0.15). There was excellent intervendor correlation of GLS by the same observer [r = 0.94, P < 0.0001; bias -1.3%, 95% CI limits of agreement (LOA) -4.8 to 2.2%). Intervendor comparison for regional longitudinal strain by coronary artery territories distribution were: LAD: r = 0.85, P < 0.0001; bias 0.5%, LOA -5.3 to 6.4%; RCA: r = 0.88, P < 0.0001; bias -2.4%, LOA -8.6 to 3.7%; LCX: r = 0.76, P < 0.0001; bias -5.3%, LOA -10.6 to 2.0%. Intervendor comparison for regional longitudinal strain by LV levels were: basal: r = 0.86, P < 0.0001; bias -3.6%, LOA -9.9 to 2.0%; mid: r = 0.90, P < 0.0001; bias -2.6%, LOA -7.8 to 2.6%; apical: r = 0.74; P < 0.0001; bias -1.3%, LOA -9.4 to 6.8%.Intervendor agreement in GLS and regional strain measurements have significantly improved after the EACVI/ASE Task Force Strain Standardization Initiatives. However, significant wide LOA still exist, especially for regional strain measurements, which remains relevant when considering vendor-specific software for serial measurements.Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email:
Recurrent acute angle-closure attack due to plateau iris syndrome after cataract extraction with or without argon laser peripheral iridoplasty: a case report. - BMC ophthalmology
We describe two cases of recurrent acute angle-closure attack in patients with plateau iris syndrome after cataract extraction. Argon laser peripheral iridoplasty and cataract extraction have been used to reduce the occurrence of acute angle-closure attack in plateau iris syndrome although the risk cannot be completely eliminated. There is no consensus on the long term management of plateau iris syndrome. This is, as far as we know, the first case report of recurrent acute angle-closure attack in plateau iris syndrome after cataract extraction.We report two cases of recurrent acute angle-closure attack in 2 Chinese patients with plateau iris syndrome. The first patient was a 69 year-old woman who received bilateral argon laser peripheral iridoplasty and cataract extraction 2 years prior to the latest acute angle-closure with right eye intraocular pressure 48 mmHg. The attack was aborted medically. Peripheral iridotomy was patent and argon laser peripheral iridoplasty marks were mostly at peripheral 2/3 of the iris. Anterior segment optical coherence tomography confirmed bilateral plateau iris configuration. Use of long term pilocarpine or repeated argon laser peripheral iridoplasty to prevent recurrent angle-closure attack was discussed but she opted for observation. The second patient was a 64 year-old man presented with acute angle-closure after cataract extraction despite placement of laser peripheral iridotomy. Plateau iris syndrome was confirmed by anterior segment optical coherence tomography and he received argon laser peripheral iridoplasty.Acute angle-closure due to plateau iris syndrome can still occur despite previous cataract extraction and argon laser peripheral iridoplasty. These are the first reported cases of recurrent acute angle-closure attack due to plateau iris syndrome following cataract extraction, with or without previous argon laser peripheral iridoplasty. Repeated treatment with argon laser peripheral iridoplasty or pilocarpine could be considered although the long term efficacy is questionable. Argon laser peripheral iridoplasty should be applied as peripheral as possible so as to open up the drainage angle effectively.
Gene-set activity toolbox (GAT): A platform for microarray-based cancer diagnosis using an integrative gene-set analysis approach. - Journal of bioinformatics and computational biology
Cancer is a complex disease that cannot be diagnosed reliably using only single gene expression analysis. Using gene-set analysis on high throughput gene expression profiling controlled by various environmental factors is a commonly adopted technique used by the cancer research community. This work develops a comprehensive gene expression analysis tool (gene-set activity toolbox: (GAT)) that is implemented with data retriever, traditional data pre-processing, several gene-set analysis methods, network visualization and data mining tools. The gene-set analysis methods are used to identify subsets of phenotype-relevant genes that will be used to build a classification model. To evaluate GAT performance, we performed a cross-dataset validation study on three common cancers namely colorectal, breast and lung cancers. The results show that GAT can be used to build a reasonable disease diagnostic model and the predicted markers have biological relevance. GAT can be accessed from where GAT's java library for gene-set analysis, simple classification and a database with three cancer benchmark datasets can be downloaded.
Genome-wide association study identifies five new susceptibility loci for primary angle closure glaucoma. - Nature genetics
Primary angle closure glaucoma (PACG) is a major cause of blindness worldwide. We conducted a genome-wide association study (GWAS) followed by replication in a combined total of 10,503 PACG cases and 29,567 controls drawn from 24 countries across Asia, Australia, Europe, North America, and South America. We observed significant evidence of disease association at five new genetic loci upon meta-analysis of all patient collections. These loci are at EPDR1 rs3816415 (odds ratio (OR) = 1.24, P = 5.94 × 10(-15)), CHAT rs1258267 (OR = 1.22, P = 2.85 × 10(-16)), GLIS3 rs736893 (OR = 1.18, P = 1.43 × 10(-14)), FERMT2 rs7494379 (OR = 1.14, P = 3.43 × 10(-11)), and DPM2-FAM102A rs3739821 (OR = 1.15, P = 8.32 × 10(-12)). We also confirmed significant association at three previously described loci (P < 5 × 10(-8) for each sentinel SNP at PLEKHA7, COL11A1, and PCMTD1-ST18), providing new insights into the biology of PACG.
Topography of claustrum and insula projections to medial prefrontal and anterior cingulate cortex of the common marmoset (Callithrix jacchus). - The Journal of comparative neurology
The claustrum has been the subject of intense research interest in recent years, driven in large part by its extensive connections with various regions of the cerebral cortex, and by hypotheses surrounding its possible role in multimodal sensory and/or sensory-emotional integration. Here we employed neuroanatomical tracers to map projections from the claustrum-insular region to the medial prefrontal and anterior cingulate cortex of the common marmoset (C. Jacchus). These areas were selected based on their identification as 'hub' areas of the default mode and cortical salience networks, respectively. Microinjections of fluorescent tracers, along with gold nanoparticle conjugated cholera toxin B-subunit and biotinylated dextran amine, were placed in subdivisions of the anterior cingulate area 24, and in medial prefrontal areas 32 and 32V. The resulting distribution of transported label showed rostral-caudal and dorsal-ventral topographic arrangement of claustrum connections, and clear rostral-caudal topography of insular projections. Medial prefrontal connections were mainly restricted to a ventromedial strip located in the rostral half of the claustrum, with a second, smaller patch of cells in the caudal, ventrolateral portion. In contrast, injections into area 24 yielded dense, widespread connections from the dorsal claustrum, extending along its entire rostral-caudal length. Projections from the "classical" agranular, disgranular, and granular insular areas were sparse or non-existent in the areas 32 and 32V, with progressively increasing connections observed in more caudal tracer injections (i.e., in subdivisions of area 24). Transported label was observed in rostral peri-insular areas OPAI, OPro, and the insular proisocortex following all prefrontal injections. These data provide a structural connectivity foundation for interpretation of functional imaging studies, which often report activity in the "anterior insula" that may arise, in part, from claustrum and/or peri-insular projections to the anterior cingulate and medial prefrontal cortices. This article is protected by copyright. All rights reserved.© 2016 Wiley Periodicals, Inc.
An integrated text mining framework for metabolic interaction network reconstruction. - PeerJ
Text mining (TM) in the field of biology is fast becoming a routine analysis for the extraction and curation of biological entities (e.g., genes, proteins, simple chemicals) as well as their relationships. Due to the wide applicability of TM in situations involving complex relationships, it is valuable to apply TM to the extraction of metabolic interactions (i.e., enzyme and metabolite interactions) through metabolic events. Here we present an integrated TM framework containing two modules for the extraction of metabolic events (Metabolic Event Extraction module-MEE) and for the construction of a metabolic interaction network (Metabolic Interaction Network Reconstruction module-MINR). The proposed integrated TM framework performed well based on standard measures of recall, precision and F-score. Evaluation of the MEE module using the constructed Metabolic Entities (ME) corpus yielded F-scores of 59.15% and 48.59% for the detection of metabolic events for production and consumption, respectively. As for the testing of the entity tagger for Gene and Protein (GP) and metabolite with the test corpus, the obtained F-score was greater than 80% for the Superpathway of leucine, valine, and isoleucine biosynthesis. Mapping of enzyme and metabolite interactions through network reconstruction showed a fair performance for the MINR module on the test corpus with F-score >70%. Finally, an application of our integrated TM framework on a big-scale data (i.e., EcoCyc extraction data) for reconstructing a metabolic interaction network showed reasonable precisions at 69.93%, 70.63% and 46.71% for enzyme, metabolite and enzyme-metabolite interaction, respectively. This study presents the first open-source integrated TM framework for reconstructing a metabolic interaction network. This framework can be a powerful tool that helps biologists to extract metabolic events for further reconstruction of a metabolic interaction network. The ME corpus, test corpus, source code, and virtual machine image with pre-configured software are available at preecha/metrecon.
Prognostic value of right ventricular free wall strain in pulmonary hypertension patients with pseudo-normalized tricuspid annular plane systolic excursion values. - The international journal of cardiovascular imaging
Pulmonary hypertension (PH) is a progressively fatal disease having a significant impact on right ventricular (RV) function, a major determinant of long-term outcome in PH patients. In our clinic we frequently noticed the combination of PH and reduced RV function, but with discordant Tricuspid Annular Plane Systolic Excursion (TAPSE) values. The present study focuses on whether RV free wall strain measured using 2-dimensional speckle-tracking echocardiography is able to predict mortality in this subgroup of PH patients. 57 patients with PH and RV dysfunction (visual echocardiographic assessment of ≥2) and pseudo-normalized TAPSE values (defined as ≥16 mm) were retrospectively evaluated. Patients were divided by RV free -20 % as cut-off value. Follow-up data on all-cause mortality were registered after a median follow-up time of 27.9 ± 1.7 months. RV free of ≥-20 % was predictive of all-cause mortality after a median follow-up time of 27.9 ± 1.7 months (HR 3.76, 95 % CI 1.02-13.92, p = 0.05). RV free ≥-20 % remained a significant predictor of all-cause mortality (HR 4.30, 95 % CI 1.11-16.61, p = 0.04) after adjusting for PH-specific treatment. On the contrary, TAPSE was not a significant predictor of all-cause mortality. RV free wall strain provides prognostic information in patients with PH and RV dysfunction, but with normal TAPSE values. Future studies with larger cohorts, longer follow-up periods and inclusion of more echocardiographic parameters measuring LV and RV function could confirm the strength of RV free ≥-20 % as a predictor of mortality for this subgroup of patients with PH.
Cyclophosphamide in dermatology. - The Australasian journal of dermatology
Cyclophosphamide is a chemotherapeutic agent which was first discovered in experimental tumours in rats, and it has since been widely used to treat malignancies and severe manifestations of various auto-immune diseases. High-dose chemotherapy and continuous daily oral regimens are associated with significant toxicity profiles, but i.v. pulsed regimens have lowered the rates of adverse effects in rheumatological studies. Cyclophosphamide has been shown to be useful in the treatment of severe autoimmune conditions due to its powerful immunosuppressive ability; however, it remains a relatively underused modality in dermatology. This article reviews the current literature on cyclophosphamide and its clinical applications in dermatology.© 2016 The Australasian College of Dermatologists.
Influence of exercise intensity and duration on functional and biochemical perturbations in the human heart. - The Journal of physiology
Strenuous endurance exercise induces transient functional and biochemical cardiac perturbations that persist for 24-48 h. The magnitude and time-course of exercise-induced reductions in ventricular function and increases in cardiac injury markers are influenced by the intensity and duration of exercise. In a human experimental model, exercise-induced reductions in ventricular strain and increases in cardiac troponin are greater, and persist for longer, when exercise is performed within the heavy- compared to moderate-intensity exercise domain, despite matching for total mechanical work. The results of the present study help us better understand the dose-response relationship between endurance exercise and acute cardiac stress/injury, a finding that has implications for the prescription of day-to-day endurance exercise regimes.Strenuous endurance exercise induces transient cardiac perturbations with ambiguous health outcomes. The present study investigated the magnitude and time-course of exercise-induced functional and biochemical cardiac perturbations by manipulating the exercise intensity-duration matrix. Echocardiograph-derived left (LV) and right (RV) ventricular global longitudinal strain (GLS), and serum high-sensitivity cardiac troponin (hs-cTnI) concentration, were examined in 10 males (age: 27 ± 4 years; V̇O2, peak : 4.0 ± 0.8 l min(-1) ) before, throughout (50%, 75% and 100%), and during recovery (1, 3, 6 and 24 h) from two exercise trials. The two exercise trials consisted of 90 and 120 min of heavy- and moderate-intensity cycling, respectively, with total mechanical work matched. LVGLS decreased (P < 0.01) during the 90 min trial only, with reductions peaking at 1 h post (pre: -19.9 ± 0.6%; 1 h post: -18.5 ± 0.7%) and persisting for >24 h into recovery. RVGLS decreased (P < 0.05) during both exercise trials with reductions in the 90 min trial peaking at 1 h post (pre: -27.5 ± 0.7%; 1 h post: -25.1 ± 0.8%) and persisting for >24 h into recovery. Serum hs-cTnI increased (P < 0.01) during both exercise trials, with concentrations peaking at 3 h post but only exceeding cardio-healthy reference limits (14 ng l(-1) ) in the 90 min trial (pre: 4.2 ± 2.4 ng l(-1) ; 3 h post: 25.1 ± 7.9 ng l(-1) ). Exercise-induced reductions in ventricular strain and increases in cardiac injury markers persist for 24 h following exercise that is typical of day-to-day endurance exercise training; however, the magnitude and time-course of this response can be altered by manipulating the intensity-duration matrix.© 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.
Collagen crosslinking in the management of leaking cystic blebs: a prospective study. - Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv für klinische und experimentelle Ophthalmologie
To evaluate the effectiveness and safety of collagen crosslinking for leaking cystic blebs.A prospective study was conducted on subjects with cystic bleb leaks without indications for urgent surgical intervention. Collagen crosslinking with riboflavin 0.1 % and ultraviolet A irradiation for 30 min was applied to the cystic bleb surface in five patients. Subjects were followed up for at least 20 weeks (mean: 35.5 ± 11.5 weeks) to monitor the length of time to the cessation of bleb leak, as well as visual acuity, intraocular pressure, and the presence of adverse effects arising from the treatment.Results showed that a single session of collagen crosslinking was effective in stopping cystic bleb leak. In two of the five subjects, the bleb leak subsided 1 week post-treatment, in one patient after 2 weeks, and in the two more complicated cases, after 4 weeks. This effect was maintained for a mean period of 33.5 ± 10.2 weeks after bleb leak cessation. Treatment was effective even in patients with friable conjunctiva following multiple surgical interventions and severe leak, although a longer period was needed for resolution of the bleb leak. The intraocular pressure and visual acuity were largely stable before and after treatment. No side effects or complications arose from this treatment.We recommend a trial of collagen crosslinking on leaking cystic blebs without indications for immediate surgical interventions. It is a relatively easy, non-invasive, pain-free, and potential repeatable procedure for treating leaking cystic blebs, with the aim of strengthening the underlying pathological conjunctiva.

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