27 results on '"Tracy Chan"'
Search Results
2. Delay in funding of tolvaptan for polycystic kidney disease in Aotearoa New Zealand
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Tracy, Chan, Walter, van der Merwe, and Janak R, de Zoysa
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Native Hawaiian or Other Pacific Islander ,Tolvaptan ,Humans ,Kidney Failure, Chronic ,Kidney ,Polycystic Kidney, Autosomal Dominant ,Antidiuretic Hormone Receptor Antagonists ,New Zealand - Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is the fifth most common cause of end stage kidney disease (ESKD) in Aotearoa New Zealand. Identification of two genes, PCKD1 and PCKD2, which cause the majority of this disease, has played a key role in the development of DNA-sequence molecular diagnostics. ADPKD is characterised by the formation and growth of multiple cysts within the kidney, with some but not all patients progressing to ESKD. The diagnosis of ADPKD is based on the presence of family history, and radiological imaging although increasingly genetic testing is being used for screening and diagnosis. Once diagnosed, standard management of ADPKD includes laboratory monitoring of chronic kidney disease (CKD) parameters, lowering of blood pressure, and a high fluid intake. Over the last decade much research has been undertaken for targeted therapies for ADPKD; however, despite funding of these medications overseas since May 2015, and applications to Te Pātaka Whaioranga, The Pharmaceutical Management Agency (PHARMAC), these therapies remain unavailable to New Zealanders resulting in an increased burden of disease to individuals and the whānau and financial cost to the health system.
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- 2022
3. Influenza Classification Suite: An automated Galaxy workflow for rapid influenza sequence analysis
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William W. L. Hsiao, Tracy Chan, Suzana Sabaiduc, Agatha N. Jassem, Catharine Chambers, Rebecca Hickman, Lauren C. Tindale, Diane Eisler, Danuta M. Skowronski, Mel Krajden, and Daniel Fornika
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Pulmonary and Respiratory Medicine ,Epidemiology ,Sequence analysis ,Influenza vaccine ,Computer science ,workflow ,data analysis ,Genomics ,Computational biology ,Herd immunity ,Short Article ,Influenza, Human ,genomics ,Humans ,Clade ,Phylogeny ,Suite ,Strain (biology) ,Public Health, Environmental and Occupational Health ,virus diseases ,Short Articles ,Sequence Analysis, DNA ,Classification ,Orthomyxoviridae ,Influenza ,Galaxy ,Infectious Diseases ,Workflow - Abstract
Influenza viruses continually evolve to evade population immunity, and the different lineages are assigned into clades based on shared mutations. We have developed a publicly available computational workflow, the Influenza Classification Suite, for rapid clade mapping of sequenced influenza viruses. This suite provides a user‐friendly workflow implemented in Galaxy to automate clade calling and antigenic site extraction. Workflow input includes clade definition and amino acid index array files, which can be customized to identify any clades of interest. The Influenza Classification Suite provides rapid, high‐resolution understanding of circulating influenza strain evolution to inform influenza vaccine effectiveness and the need for potential vaccine reformulation.
- Published
- 2020
4. Vaccine Effectiveness Against Lineage-matched and -mismatched Influenza B Viruses Across 8 Seasons in Canada, 2010–2011 to 2017–2018
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Catharine Chambers, Danuta M. Skowronski, Yan Li, Jonathan B. Gubbay, Suzana Sabaiduc, Christine Martineau, Gaston De Serres, Hugues Charest, Tracy Chan, Anne-Luise Winter, Steven J. Drews, Kevin Fonseca, Mel Krajden, James A. Dickinson, Caren Rose, Martin Petric, Agatha N. Jassem, Rebecca Hickman, and Nathalie Bastien
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Adult ,Male ,0301 basic medicine ,Microbiology (medical) ,Trivalent influenza vaccine ,Canada ,cross-protection ,Lineage (genetic) ,Adolescent ,Databases, Factual ,Cross Protection ,030106 microbiology ,Young Adult ,03 medical and health sciences ,Immunogenicity, Vaccine ,0302 clinical medicine ,Vaccine strain ,influenza vaccine effectiveness ,Influenza, Human ,Humans ,Medicine ,030212 general & internal medicine ,Child ,Vaccine Potency ,Aged ,Influenza B viruses ,business.industry ,Influenzavirus B ,repeat vaccination ,Infant ,Middle Aged ,influenza B virus ,Virology ,3. Good health ,Vaccination ,Infectious Diseases ,Immunization ,Influenza Vaccines ,Child, Preschool ,Epidemiological Monitoring ,Female ,Brief Reports ,Seasons ,business ,lineage - Abstract
Vaccine effectiveness (VE) against influenza B was derived separately for Victoria and Yamagata lineages across 8 seasons (2010–2011 to 2017–2018) in Canada when trivalent influenza vaccine was predominantly used. VE was ≥50% regardless of lineage match to circulating viruses, except when the vaccine strain was unchanged from the prior season.
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- 2018
5. Evaluation of CR2-Haptic Movement Quality Assessment Module for Hand
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Patrick Jun Hua Chin, Yashitha Devi Silvadorai, Hisyam Abdul Rahman, Hadafi Fitri Mohd Latip, Nimalan Arumugam, Che Fai Yeong, Najib bin Abdullah, Muhammad Farhan bin Mustar, Tracy Chan, Qamer Iqbal Khan, Eileen Lee Ming Su, Aqilah Leela T. Narayanan, Kang Xiang Khor, and Yvonne Yee Woon Khor
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medicine.medical_specialty ,Rehabilitation ,Relation (database) ,Computer science ,Movement (music) ,medicine.medical_treatment ,Kinematics ,Wrist ,Movement assessment ,medicine.anatomical_structure ,Physical medicine and rehabilitation ,Forearm ,medicine ,Haptic technology - Abstract
Objective assessment is crucial in the rehabilitation process for physiotherapists to determine the progress of the patient and to provide the best treatment in therapy. However, current rehabilitations rely heavily on manual labour and lack objective assessments, as well as quantitative diagnosis and evaluation. This project aims to evaluate the movement assessment modules of CR2-Haptic, a portable and reconfigurable rehabilitation robot that can be used to provide an objective assessment for the targeted movement of upper limb. Both wrist and forearm movement performance were assessed in the study. Centre-out-point-to-point (CO-PTP) approach was used in the movement quality assessment module of CR2-Haptic and the proposed coordination score showed high correlation with four kinematic variables of the movement including total trial time which has the strongest relation with r2 value of 0.85, followed by smoothness (r2 = 0.80), mean velocity (r2 = 0.78) and path ratio (r2 = 0.70).
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- 2021
6. Improving Weight Measurement Compliance in the Intensive Care Unit
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Saba A. Ghaleb, Roxanne L. Roth, Tracy Chan, and Claude (Bud) Lauderbach
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General Medicine - Published
- 2022
7. Influenza Vaccine Effectiveness by A(H3N2) Phylogenetic Subcluster and Prior Vaccination History: 2016-2017 and 2017-2018 Epidemics in Canada
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Steven J. Drews, Suzana Sabaiduc, Gaston De Serres, Macy Zou, Yan Li, Rebecca Hickman, Mel Krajden, Tracy Chan, Catharine Chambers, Romy Olsha, Agatha N. Jassem, Danuta M. Skowronski, Nathalie Bastien, Siobhan Leir, Caren Rose, James A. Dickinson, Hugues Charest, Anne-Luise Winter, and Jonathan B. Gubbay
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Canada ,Influenza vaccine ,Hemagglutinin (influenza) ,Vaccine Efficacy ,Disease cluster ,Antigen ,Influenza, Human ,Immunology and Allergy ,Medicine ,Humans ,Clade ,Epidemics ,Phylogeny ,Phylogenetic tree ,biology ,business.industry ,Influenza A Virus, H3N2 Subtype ,Vaccination ,Influenza a ,Virology ,Infectious Diseases ,Influenza Vaccines ,biology.protein ,Seasons ,business - Abstract
Background The influenza A(H3N2) vaccine was updated from clade 3C.3a in 2015–2016 to 3C.2a for 2016–2017 and 2017–2018. Circulating 3C.2a viruses showed considerable hemagglutinin glycoprotein diversification and the egg-adapted vaccine also bore mutations. Methods Vaccine effectiveness (VE) in 2016–2017 and 2017–2018 was assessed by test-negative design, explored by A(H3N2) phylogenetic subcluster and prior season’s vaccination history. Results In 2016–2017, A(H3N2) VE was 36% (95% confidence interval [CI], 18%–50%), comparable with (43%; 95% CI, 24%–58%) or without (33%; 95% CI, −21% to 62%) prior season’s vaccination. In 2017–2018, VE was 14% (95% CI, −8% to 31%), lower with (9%; 95% CI, −18% to 30%) versus without (45%; 95% CI, −7% to 71%) prior season’s vaccination. In 2016–2017, VE against predominant clade 3C.2a1 viruses was 33% (95% CI, 11%–50%): 18% (95% CI, −40% to 52%) for 3C.2a1a defined by a pivotal T135K loss of glycosylation; 60% (95% CI, 19%–81%) for 3C.2a1b (without T135K); and 31% (95% CI, 2%–51%) for other 3C.2a1 variants (with/without T135K). VE against 3C.2a2 viruses was 45% (95% CI, 2%–70%) in 2016–2017 but 15% (95% CI, −7% to 33%) in 2017–2018 when 3C.2a2 predominated. VE against 3C.2a1b in 2017–2018 was 37% (95% CI, −57% to 75%), lower at 12% (95% CI, −129% to 67%) for a new 3C.2a1b subcluster (n = 28) also bearing T135K. Conclusions Exploring VE by phylogenetic subcluster and prior vaccination history reveals informative heterogeneity. Pivotal mutations affecting glycosylation sites, and repeat vaccination using unchanged antigen, may reduce VE.
- Published
- 2019
8. P697 Feasibility of HPV self-collection for cervix screening in under-screened street entrenched women
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Celena Falkner, Sandra Allison, Kate Shannon, Deborah Money, Tracy Chan, Sheona Mitchell-Foster, Jill Chettiar, Laurie Smith, C Sarai Racey, Marette Lee, Darrel Cook, Tracey Day, Heather Pedersen, and Gina Ogilvie
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Colposcopy ,education.field_of_study ,medicine.medical_specialty ,Cervical screening ,Hysterectomy ,medicine.diagnostic_test ,business.industry ,Medical record ,medicine.medical_treatment ,Population ,female genital diseases and pregnancy complications ,Underserved Population ,medicine.anatomical_structure ,Family medicine ,medicine ,business ,education ,Cervix ,Reproductive health - Abstract
Background HPV self-collection is a promising approach to improve uptake of cervical screening in under-screened women. The aim of this feasibility study was to measure uptake of HPV self-collection, HPV positivity, and screening history of street entrenched women in a rural region centre. Methods Women 30–69 years of age, attending drop-in community-based primary care and integrative reproductive health clinics in Northern British Columbia (BC), Canada and self-reported not having received cervix screening in the last 3 years, were offered self-collection for HPV testing. A convenience sample of all comers was administered a questionnaire and underwent a medical chart review, including the provincial cervix screening registry. Demographics, HIV status, and cervix screening history were collected. All women who tested HPV16/18 positive were referred for colposcopy. Results A total of 66 eligible women were analyzed (mean age 43.3 years), with population saturation reached after 3 months recruitment. An additional 11 women were deemed ineligible due to age or prior hysterectomy. 83% self-reported as Indigenous. Based on the provincial cervix screening registry, 48% of women were up-to-date on cervix screening based on triennial screening guidelines. All women undertook self-collection and the majority of women reported high perceived acceptability, safety, and accuracy of HPV self-collection. HPV 16/18 positivity was 7.6%, with 40% co-infected with HIV. Overall HIV prevalence was 16.4%, however, over 25% of women had unknown HIV status based on medical chart review. Conclusion HPV self-collection was highly acceptable as part of community-based integrative reproductive health services. Despite being a traditionally underserved population, and women self-reporting being overdue for screening, over half the women were up to date on cervix screening, albeit regular screening was lacking for many. The findings from this feasibility study will inform future implementation of HPV self-collection to improve and maintain regular cervix screening services in street entrenched women. Disclosure No significant relationships.
- Published
- 2019
9. Interim estimates of 2018/19 vaccine effectiveness against influenza A(H1N1)pdm09, Canada, January 2019
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Tracy Chan, Nathalie Bastien, Jonathan B. Gubbay, James A. Dickinson, Suzana Sabaiduc, Gaston De Serres, Hugues Charest, Yan Li, Mel Krajden, Romy Olsha, Matthew A. Croxen, Michelle Murti, Siobhan Leir, and Danuta M. Skowronski
- Subjects
0301 basic medicine ,Male ,influenza virus ,Influenza A Virus, H1N1 Subtype ,Interim ,Nasopharynx ,Epidemiology ,Outcome Assessment, Health Care ,Child ,Vaccination ,immunisation ,vaccines ,Middle Aged ,Influenza Vaccines ,Child, Preschool ,Vaccine-preventable diseases ,epidemiology ,Female ,Seasons ,influenza ,Rapid Communication ,Adult ,medicine.medical_specialty ,Canada ,Adolescent ,viral infections ,030106 microbiology ,influenza-like illness ,Nose ,Real-Time Polymerase Chain Reaction ,Sensitivity and Specificity ,03 medical and health sciences ,Virology ,Influenza, Human ,medicine ,genomics ,Humans ,Vaccine Potency ,Aged ,Influenza-like illness ,vaccine effectiveness ,business.industry ,Public Health, Environmental and Occupational Health ,Case-control study ,Infant ,Sequence Analysis, DNA ,Hemagglutination Inhibition Tests ,Confidence interval ,030104 developmental biology ,vaccine-preventable diseases ,Case-Control Studies ,ILI ,business ,laboratory ,Sentinel Surveillance ,Demography - Abstract
Using a test-negative design, the Canadian Sentinel Practitioner Surveillance Network assessed interim 2018/19 vaccine effectiveness (VE) against predominant influenza A(H1N1)pdm09 viruses. Adjusted VE was 72% (95% confidence interval: 60 to 81) against medically attended, laboratory-confirmed influenza A(H1N1)pdm09 illness. This substantial vaccine protection was observed in all age groups, notably young children who appeared to be disproportionately affected. Sequence analysis identified heterogeneity in emerging clade 6B.1 viruses but no dominant drift variant.
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- 2019
10. Currency composition of reserves, trade invoicing and currency movements
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Hiroyuki Ito, Robert N. McCauley, and Tracy Chan
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Economics and Econometrics ,Reserve currency ,Currency ,Economics ,Devaluation ,International economics ,Business and International Management ,Unit of account ,Foreign exchange risk ,Monetary base ,Special drawing rights ,Foreign-exchange reserves - Abstract
This article analyses the relationships among the unit of account and means of exchange functions of an international currency, on the one hand, and its store of value in official use, on the other hand. Historical evidence links the currency composition of reserves to currency movements. The currency composition of reserves is strongly related in the cross-section to both currency movements and the currency denomination of trade. Data limitations make it hard to distinguish these two factors. A panel analysis of 5 countries from central and Eastern Europe shows that both trade invoicing and currency movements drive changing official reserve composition. Implications are suggested for the prospects for the renminbi enlarging its current small portion of official foreign exchange reserves.
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- 2015
11. Opportunities for HPV self-collection to improve cervical cancer screening uptake in street entrenched women in rural regional centres
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Darrel Cook, Marette Lee, Jill Chettiar, Deborah Money, Sandra Alison, Celena Falkner, Kate Shannon, Tracey Day, Sheona Mitchell-Foster, Gina Ogilvie, Laurie Smith, C Sarai Racey, Heather Pedersen, and Tracy Chan
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medicine.medical_specialty ,business.industry ,Family medicine ,medicine ,Obstetrics and Gynecology ,Self collection ,Cervical cancer screening ,business - Published
- 2019
12. Evaluation of a validated methylation triage signature for human papillomavirus positive women in the HPV FOCAL cervical cancer screening trial
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Darrel A, Cook, Mel, Krajden, Adam R, Brentnall, Lovedeep, Gondara, Tracy, Chan, Jennifer H, Law, Laurie W, Smith, Dirk J, van Niekerk, Gina S, Ogilvie, Andrew J, Coldman, Rhian, Warman, Caroline, Reuter, Jack, Cuzick, and Attila T, Lorincz
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Adult ,Risk ,Human papillomavirus 16 ,Human papillomavirus 18 ,Tumor Markers and Signatures ,cervical cancer ,Papillomavirus Infections ,cervical cancer screening ,Uterine Cervical Neoplasms ,Cell Biology ,Middle Aged ,colposcopy triage ,Methylation ,female genital diseases and pregnancy complications ,United States ,Europe ,Case-Control Studies ,Humans ,Female ,human papillomavirus ,Early Detection of Cancer ,Aged - Abstract
Human papillomavirus (HPV)‐based cervical cancer screening requires triage of HPV positive women to identify those at risk of cervical intraepithelial neoplasia grade 2 (CIN2) or worse. We conducted a blinded case–control study within the HPV FOCAL randomized cervical cancer screening trial of women aged 25–65 to examine whether baseline methylation testing using the S5 classifier provided triage performance similar to an algorithm relying on cytology and HPV genotyping. Groups were randomly selected from women with known HPV/cytology results and pathology outcomes. Group 1: 104 HPV positive (HPV+), abnormal cytology (54 CIN2/3; 50, What's new? DNA methylation testing could simplify the triage process for screening HPV+ women for cervical cancer, according to new results from a case‐control study. Most pre‐cancerous cervical lesions do not progress to cancer, so triage is done to identify those lesions more likely to become cancerous and boost screening specificity. Here, the authors tested women in the HPV FOCAL study for baseline methylation using the S5 classifier. Methylation signatures, they found, performed with 93% sensitivity and 18% PPV for CIN3, comparable to the combination of cytology and HPV genotyping (86% sensitivity and 19% PPV).
- Published
- 2018
13. Early season co-circulation of influenza A(H3N2) and B(Yamagata): interim estimates of 2017/18 vaccine effectiveness, Canada, January 2018
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Nathalie Bastien, Mel Krajden, Yan Li, Jonathan B. Gubbay, James A. Dickinson, Steven J. Drews, Catharine Chambers, Danuta M. Skowronski, Rebecca Hickman, Gaston De Serres, Hugues Charest, Anne-Luise Winter, Agatha N. Jassem, and Tracy Chan
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0301 basic medicine ,medicine.medical_specialty ,Epidemiology ,influenza virus ,03 medical and health sciences ,0302 clinical medicine ,Antigen ,Virology ,Interim ,genomics ,medicine ,030212 general & internal medicine ,vaccine effectiveness ,business.industry ,Public Health, Environmental and Occupational Health ,virus diseases ,Influenza a ,mid-season ,Influenza ,Confidence interval ,Vaccination ,vaccine-preventable diseases ,vaccines and immunisation ,030104 developmental biology ,Immunization ,Vaccine-preventable diseases ,business ,Rapid Communication - Abstract
Using a test-negative design, we assessed interim vaccine effectiveness (VE) for the 2017/18 epidemic of co-circulating influenza A(H3N2) and B(Yamagata) viruses. Adjusted VE for influenza A(H3N2), driven by a predominant subgroup of clade 3C.2a viruses with T131K + R142K + R261Q substitutions, was low at 17% (95% confidence interval (CI): −14 to 40). Adjusted VE for influenza B was higher at 55% (95% CI: 38 to 68) despite prominent use of trivalent vaccine containing lineage-mismatched influenza B(Victoria) antigen, suggesting cross-lineage protection.
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- 2018
14. Emerging market local currency bonds: Diversification and stability
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Ken Miyajima, Madhusudan Mohanty, and Tracy Chan
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Currency mismatches, emerging market local currency bond, diversification benefit, safe asset, panel VAR ,Economics and Econometrics ,Bond ,Diversification (finance) ,Economics ,Government bond ,Stability (learning theory) ,Local currency ,Monetary economics ,Business and International Management ,Emerging markets ,Global risk ,Treasury - Abstract
Over the past three years, cross-border inflows into emerging market (EM) local currency bonds have surged. The returns on these bonds have moved more closely with those on international assets regarded as "safe", particularly following the euro area debt crisis. This paper first demonstrates that domestic factors have tended to dictate the dynamics of the EM local currency government yield. The importance of local drivers has probably increased the potential diversification benefit, creating strong appetite for the asset class. Second, the paper confirms that EM local currency government yields have behaved more like safe haven yields since 2008: they have dropped, rather than increased, in response to worsening global risk sentiment. Yet EM local currency government yields could be susceptible to adverse external shocks: the yield dynamics have been affected by unsustainably low US Treasury yields. Moreover, the international role of EM local currency bonds depends crucially on the behaviour of exchange rates. Nevertheless, the further development of local currency bond markets should help strengthen the stability of the international monetary and financial system.
- Published
- 2015
15. Complete Genome Sequence of Mycobacterium chimaera SJ42, a Nonoutbreak Strain from an Immunocompromised Patient with Pulmonary Disease
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Inanc Birol, René L. Warren, Marc G. Romney, Patrick Tang, David C. Alexander, Michael J. Strong, Christine Y. Turenne, Robin Coope, Monica Ng, L. Elaine Epperson, Daniel MacMillan, Nabeeh A. Hasan, Steven J.M. Jones, Stephen Pleasance, Tracy Chan, Mabel Rodrigues, Allyson Malecha, and Jennifer L. Gardy
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0301 basic medicine ,Whole genome sequencing ,biology ,Pulmonary disease ,Immunocompromised patient ,biology.organism_classification ,medicine.disease ,bacterial infections and mycoses ,Virology ,3. Good health ,Nontuberculous mycobacterium ,03 medical and health sciences ,Opportunistic pathogen ,030104 developmental biology ,Genetics ,medicine ,Disseminated disease ,Nanopore sequencing ,Prokaryotes ,Molecular Biology ,Mycobacterium - Abstract
Mycobacterium chimaera , a nontuberculous mycobacterium (NTM) belonging to the Mycobacterium avium complex (MAC), is an opportunistic pathogen that can cause respiratory and disseminated disease. We report the complete genome sequence of a strain, SJ42, isolated from an immunocompromised male presenting with MAC pneumonia, assembled from Illumina and Oxford Nanopore data.
- Published
- 2017
16. The de-guanidinylated derivative of peramivir remains a potent inhibitor of influenza neuraminidase
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Jeremy E. Wulff, Martin J. Boulanger, Tracy Chan, Michael G. Brant, Jeremy W. Mason, Martine D. Lunke, Caleb M. Bromba, and Martin Petric
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Models, Molecular ,Drug ,medicine.drug_class ,media_common.quotation_subject ,Clinical Biochemistry ,Acids, Carbocyclic ,Neuraminidase ,Pharmaceutical Science ,Cyclopentanes ,Pharmacology ,Crystallography, X-Ray ,Antiviral Agents ,Guanidines ,Biochemistry ,Inhibitory Concentration 50 ,chemistry.chemical_compound ,Zanamivir ,Drug Discovery ,medicine ,Humans ,Potency ,Enzyme Inhibitors ,Guanidine ,Molecular Biology ,media_common ,Dose-Response Relationship, Drug ,Molecular Structure ,biology ,Neuraminidase inhibitor ,Chemistry ,Organic Chemistry ,Virology ,Recombinant Proteins ,In vitro ,Influenza A virus ,Drug Design ,biology.protein ,Molecular Medicine ,Peramivir ,Protein Binding ,medicine.drug - Abstract
The guanidine function in the potent neuraminidase inhibitor peramivir was included early on in the drug design process, and examination of X-ray structural data for the enzyme-inhibitor complex would seem to indicate that the guanidine plays a critical role in promoting binding. However, this functional group may also contribute to the poor oral availability of the drug. Given that the relative stereochemistry on the guanidine-bearing carbon in peramivir is opposite to that in zanamivir (a related neuraminidase inhibitor, for which the guanidine function is known to contribute substantially to the potency), we sought to determine the importance of the guanidine group to peramivir's overall potency. Here we report that the de-guanidinylated analogue of peramivir is only ca. 1-order of magnitude less potent than peramivir itself in two in vitro inhibition assays. This suggests that next-generation inhibitors designed to improve on peramivir's properties might profitably dispense with the guanidine function.
- Published
- 2011
17. Influenza B/Victoria Antigen Induces Strong Recall of B/Yamagata But Lower B/Victoria Response in Children Primed With Two Doses of B/Yamagata
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Martin Petric, Gaston De Serres, Naveed Z. Janjua, Suzana Sabaiduc, Travis S. Hottes, Tracy Chan, Brian J. Ward, and Danuta M. Skowronski
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Microbiology (medical) ,Influenza vaccine ,Molecular Sequence Data ,Immunization, Secondary ,Hemagglutinins, Viral ,Antibodies, Viral ,Viral genetics ,Antigen ,Humans ,Medicine ,Antigens, Viral ,Viral immunology ,biology ,business.industry ,Vaccination ,Infant ,Sequence Analysis, DNA ,Hemagglutination Inhibition Tests ,Virology ,Influenza B virus ,Infectious Diseases ,Vaccines, Inactivated ,Immunization ,Influenza Vaccines ,Pediatrics, Perinatology and Child Health ,Immunology ,biology.protein ,RNA, Viral ,Antibody ,business ,Immunologic Memory ,Immunologic memory - Abstract
Trivalent inactivated influenza vaccine (TIV) contains 1 of 2 influenza B/lineages (B/Yamagata or B/Victoria) annually. We assessed prime-boost responses in young children following a change in the B/lineage included in TIV.Participants were primed during a clinical trial as infants or toddlers with two 0.25 or two 0.5 mL doses of 2008-2009 TIV containing B/Florida/4/06(Yamagata) antigen. In subsequent years, sequential subsets received annual age-appropriate doses of 2009-2010 and 2010-2011 TIV containing the changed influenza B/lineage antigen (B/Brisbane/60/08(Victoria)). Serologic response was assessed pre- and postimmunization by hemagglutination inhibition (HI; with/without ether treatment of influenza B antigen) and microneutralization. The primary immunogenicity outcome was the seroprotection rate (SPR) measured by HI without ether treatment (SPR:HI titers ≥40).Fifty-six children were included in 2009-2010 and 36 in 2010-2011 analyses. Before the 2009-2010 TIV dose, antibody to all 2008-2009 TIV components had fallen to low levels: SPR10% for B/Florida/4/06(Yamagata) and B/Brisbane/60/08(Victoria) antigens. A single 2009-2010 TIV dose boosted antibody to the shared 2008-2009/2009-2010 influenza A antigens and to the priming 2008-2009 B/Florida/4/06(Yamagata) antigen with SPRs85%. In contrast, antibody to the B/Brisbane/60/08(Victoria) antigen included in the 2009-2010 TIV remained low: SPR25%. Antibody to the B/Brisbane/60/08(Victoria) antigen was not improved from a further dose in the 2010-2011 TIV: SPR 31% versus SPR 69% to B/Yamagata. A similar pattern of B/Yamagata dominance was observed when HI testing was conducted with antigen prepared by ether treatment.Repeated annual TIV doses containing B/Victoria-lineage antigen strongly recalled antibodies to the B/Yamagata antigen of first exposure, but elicited lower B/Victoria responses.
- Published
- 2011
18. Randomized Controlled Trial of Dose Response to Influenza Vaccine in Children Aged 6 to 23 Months
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Gaston De Serres, David W. Scheifele, Martin Petric, Travis S. Hottes, Mei Chong, Suzana Sabaiduc, Brian J. Ward, Danuta M. Skowronski, Scott A. Halperin, Naveed Z. Janjua, and Tracy Chan
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Male ,Pediatrics ,medicine.medical_specialty ,Influenza vaccine ,law.invention ,Randomized controlled trial ,law ,Influenza, Human ,Immunogenetics ,Humans ,Medicine ,Dosing ,Adverse effect ,Reactogenicity ,Dose-Response Relationship, Drug ,business.industry ,Immunogenicity ,Age Factors ,Infant ,Confidence interval ,Titer ,Vaccines, Inactivated ,Influenza Vaccines ,Pediatrics, Perinatology and Child Health ,Female ,business - Abstract
OBJECTIVES: We assessed whether 2 full versus 2 half-doses of trivalent inactivated influenza vaccine (TIV) could improve immunogenicity without increasing reactogenicity in infants (aged 6–11 months) and toddlers (aged 12–23 months). METHODS: Previously unimmunized infants and toddlers were separately randomly assigned to receive 2 full (0.5-mL) or 2 half (0.25-mL) doses of 2008–2009 split TIV. Sera were collected at enrollment and at 27 to 45 days after the second injection. Parents recorded adverse events after each injection. The primary immunogenicity outcome was superiority (1-sided, α = 0.025) of the full versus the half-dose based on a >10% increase in rates of seroprotection (hemagglutination inhibition titer of ≥40). The primary reactogenicity outcome was fever of ≥38°C within 3 days of either injection. RESULTS: In per-protocol analyses, 252 participants (full dose: n = 124; half-dose: n = 128) were included. In toddlers, postimmunization seroprotection rates exceeded 85% for all 3 vaccine components without significant difference by dose. In infants, the full dose induced higher responses for all 3 vaccine components, meeting the 10% test of superiority for the H3N2 (75.4% vs 47.6%; Δ = 27.8% [95% confidence interval (CI): 11.2–44.5]; P = .02) and B/Yamagata (70.2% vs 41.3%; Δ = 28.9% [95% CI: 11.9–45.9]; P = .02) components but not H1N1 (71.9% vs 54.0%; Δ = 18.0% [95% CI: 1.0–34.9]; P = .2). Rates of fever were not increased among full- versus half-dose recipients in either age group (5.6% vs 12.7% combined). CONCLUSIONS: Administration of 2 full TIV doses may improve immunogenicity without increasing reactogenicity in infants. Current TIV dosing recommendations for young children warrant additional evaluation.
- Published
- 2011
19. Seasonal Influenza Vaccine and Increased Risk of Pandemic A/H1N1-Related Illness: First Detection of the Association in British Columbia, Canada
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Travis S. Hottes, William Osei, Gaston De Serres, Evan M. Adams, David M. Patrick, Suzana Sabaiduc, Marcus Lem, Martin Petric, Annie Mak, Naveed Z. Janjua, Patrick Tang, Danuta M. Skowronski, David Bowering, and Tracy Chan
- Subjects
Microbiology (medical) ,Adult ,Male ,medicine.medical_specialty ,Adolescent ,Influenza vaccine ,Prevalence ,Logistic regression ,Antibodies, Viral ,Risk Assessment ,Major Articles ,Disease Outbreaks ,Interviews as Topic ,Young Adult ,Influenza A Virus, H1N1 Subtype ,Neutralization Tests ,Pandemic ,Epidemiology ,Influenza, Human ,medicine ,Humans ,Risk factor ,Child ,Articles and Commentaries ,Aged ,Aged, 80 and over ,British Columbia ,business.industry ,Outbreak ,Infant ,Odds ratio ,Hemagglutination Inhibition Tests ,Middle Aged ,Infectious Diseases ,Influenza Vaccines ,Child, Preschool ,Immunology ,Female ,business ,Demography - Abstract
Background. In April 2009, an elementary school outbreak of pandemic H1N1 (pH1N1) influenza was reported in a community in northern British Columbia, Canada-an area that includes both non-Aboriginal and Aboriginal residents living on or off a reserve. During the outbreak investigation, we explored the relationship between prior receipt of trivalent inactivated influenza vaccine (TIV) and pH1N1-related illness. Methods. A telephone survey was conducted from 15 May through 5 June 2009 among households of children attending any school in the affected community. Members of participating households where influenza-like illness (ILI) was described were then invited to submit blood samples for confirmation of pH1N1 infection by hemagglutination inhibition and microneutralization assays. Circulation of pH1N1 was concentrated among households of the elementary school and elsewhere on-reserve to which analyses of TIV effect were thus restricted. Odds ratios (ORs) for the TIV effect on ILI were computed through logistic regression, with adjustment for age, comorbidity, household density, and Aboriginal status. The influence of within-household clustering was assessed through generalized-linear-mixed models. Results. Of 408 participants, 92 (23%) met ILI criteria: 29 (32%) of 92 persons with ILI, compared with 61 (19%) 316 persons without ILI, had received the 2008–2009 formulation of TIV. Fully adjusted ORs for 2008- 2009 TIV effect on ILI were 2.45 (95% confidence interval, 1.34–4.48) by logistic regression and 2.68 [95% confidence interval, 1.37–5.25) by generalized-linear-mixed model. Conclusions. An outbreak investigation in British Columbia during the late spring of 2009 provided the first indication of an unexpected association between receipt of TIV and pH1N1 illness. This led to 5 additional studies through the summer 2009 in Canada, each of which corroborated these initial findings.
- Published
- 2010
20. Component‐Specific Effectiveness of Trivalent Influenza Vaccine as Monitored through a Sentinel Surveillance Network in Canada, 2006–2007
- Author
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Tracy Chan, Nathalie Bastien, Trijntje L. Kwindt, Martin Petric, Gaston De Serres, Kevin Fonseca, Yan Li, Danuta M. Skowronski, Annie Mak, Hugues Charest, and James A. Dickinson
- Subjects
Adult ,Male ,Trivalent influenza vaccine ,Canada ,Adolescent ,Influenza vaccine ,Molecular Sequence Data ,Hemagglutinin Glycoproteins, Influenza Virus ,Young Adult ,Influenza A Virus, H1N1 Subtype ,Influenza, Human ,Humans ,Immunology and Allergy ,Medicine ,Child ,Aged ,Aged, 80 and over ,Influenza-like illness ,Hemagglutination assay ,Reverse Transcriptase Polymerase Chain Reaction ,business.industry ,Influenza A Virus, H3N2 Subtype ,virus diseases ,Influenza a ,Sequence Analysis, DNA ,Odds ratio ,Hemagglutination Inhibition Tests ,Middle Aged ,Virology ,Confidence interval ,Vaccination ,Influenza B virus ,Infectious Diseases ,Vaccines, Inactivated ,Influenza Vaccines ,Female ,business ,Sentinel Surveillance - Abstract
Background Trivalent inactivated influenza vaccine (TIV) is reformulated annually to contain representative strains of 2 influenza A subtypes (H1N1 and H3N2) and 1 B lineage (Yamagata or Victoria). We describe a sentinel surveillance approach to link influenza variant detection with component-specific vaccine effectiveness (VE) estimation. Methods The 2006-2007 TIV included A/NewCaledonia/20/1999(H1N1)-like, A/Wisconsin/67/2005(H3N2)-like, and B/Malaysia/2506/2004(Victoria)-like components. Included participants were individuals >or=9 years of age who presented within 1 week after influenza like illness onset to a sentinel physician between November 2006 and April 2007. Influenza was identified by real-time reverse-transcriptase polymerase chain reaction and/or culture. Isolates were characterized by hemagglutination inhibition assay (HI) and HA1 gene sequence. VE was estimated as 1-[odds ratio for influenza in vaccinated versus nonvaccinated persons]. Results A total of 841 participants contributed: 69 (8%) were >or=65 years of age; 166 (20%) received the 2006-2007 TIV. Influenza was detected in 337 subjects (40%), distributed as follows: A/H3N2, 242 (72%); A/H1N1, 55 (16%); and B, 36 (11%). All but 1 of the A/H1N1 isolates were well matched, half of A/H3N2 isolates were strain mismatched, and all B isolates were lineage-level mismatched to vaccine. Age-adjusted estimated VE for A/H1N1, A/H3N2, and B components was 92% (95% CI, 40%-91%), 41% (95% CI, 6%-63%), and 19% (95% CI, -112% to 69%), respectively, with an overall VE estimate of 47% (95% CI, 18%-65%). Restriction of the analysis to include only working-age adults resulted in lower VE estimates with wide confidence intervals but similar component-specific trends. Conclusions Sentinel surveillance provides a broad platform to link new variant detection and the composite of circulating viruses to annual monitoring of component-specific VE.
- Published
- 2009
21. Currency movements drive reserve composition
- Author
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Robert N McCauley and Tracy Chan
- Subjects
jel:F31 ,jel:E58 ,jel:F33 - Abstract
A long-standing puzzle in international finance is the durability of the dollar's share of foreign exchange reserves - which remains above 60%, while the weight of the US economy in global output has fallen to less than a quarter. We argue that the dollar's role may reflect instead the share of global output produced in countries with relatively stable dollar exchange rates - the "dollar zone". If a currency varies less against the dollar than against other major currencies, then a reserve portfolio with a substantial dollar share poses less risk when returns are measured in domestic currency. Time series and cross-sectional evidence supports the link between currency movements and the currency composition of reserves.
- Published
- 2014
22. The development of musicals in Hong Kong
- Author
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Tracy. Chan
- Subjects
Economic growth ,Political science - Published
- 2012
23. Immuno-epidemiologic correlates of pandemic H1N1 surveillance observations: higher antibody and lower cell-mediated immune responses with advanced age
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Travis S. Hottes, Gaston De Serres, Beth Gentleman, Janet E. McElhaney, Naveed Z. Janjua, Martin Petric, Suzana Sabaiduc, Dale Purych, Jennifer L. Gardy, Danuta M. Skowronski, Robert C. Brunham, Tracy Chan, and David M. Patrick
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Adult ,Male ,Hemagglutination Inhibition Tests ,Adolescent ,medicine.medical_treatment ,chemical and pharmacologic phenomena ,Biology ,Antibodies, Viral ,Influenza A Virus, H2N2 Subtype ,Young Adult ,Major Articles and Brief Reports ,Immune system ,Influenza A Virus, H1N1 Subtype ,Immunity ,Neutralization Tests ,Influenza, Human ,medicine ,Immunology and Allergy ,Seroprevalence ,Humans ,Lymphocytes ,Young adult ,Child ,Pandemics ,Aged ,Aged, 80 and over ,Hemagglutination assay ,Influenza A Virus, H3N2 Subtype ,Age Factors ,Infant, Newborn ,Infant ,Middle Aged ,Infectious Diseases ,Cytokine ,Child, Preschool ,Immunology ,biology.protein ,Female ,Antibody - Abstract
Background. Pandemic H1N1 (pH1N1) surveillance data showed lower attack rates but higher risk of severe outcomes with advanced age. We explored immuno-epidemiologic correlates of surveillance findings including humoral and cell-mediated immunity (CMI). Methods. In an age-based design, ∼100 banked/residual sera per 10-year age stratum were assessed by hemagglutination inhibition (HI) and microneutralization (MN) assays for preexisting antibody to pH1N1 and recent seasonal H1N1 and H3N2 strains. In a separate birth cohort design defined by childhood influenza A/subtype priming (1919–1929: H1N1; 1945–1949: H1N1; 1958–1960: H2N2; 1969–1970: H3N2; 1978–1989: H3N2/H1N1), whole blood was collected from up to 50 volunteers per birth cohort. The ratio of Th1(IFN-γ):Th2(IL-10) cytokine responses was evaluated in vitro. Results. Antibody to seasonal viruses was highest in school-age children. Cross-reactive HI/MN antibody to pH1N1 was low among participants
- Published
- 2011
24. Prevalence of seroprotection against the pandemic (H1N1) virus after the 2009 pandemic
- Author
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Travis S. Hottes, Gaston De Serres, Suzana Sabaiduc, Naveed Z. Janjua, Martin Petric, Tracy Chan, David M. Patrick, Danuta M. Skowronski, Janet E. McElhaney, Jennifer L. Gardy, and Dale Purych
- Subjects
Adult ,Male ,Group based ,Hemagglutination Inhibition Tests ,Adolescent ,Antibodies, Viral ,Young Adult ,Influenza A Virus, H1N1 Subtype ,Pandemic ,Influenza, Human ,Medicine ,Humans ,Young adult ,Child ,Pandemics ,Aged ,Aged, 80 and over ,Hemagglutination assay ,British Columbia ,business.industry ,Research ,Vaccination ,Age Factors ,Infant ,General Medicine ,Middle Aged ,H1n1 virus ,Titer ,Influenza Vaccines ,Child, Preschool ,Immunology ,Female ,business ,Demography - Abstract
Background: Before pandemic (H1N1) 2009, less than 10% of serum samples collected from all age groups in the Lower Mainland of British Columbia, Canada, showed seroprotection against the pandemic (H1N1) 2009 virus, except those from very elderly people. We reassessed this profile of seroprotection by age in the same region six months after the fall 2009 pandemic and vaccination campaign. Methods: We evaluated 100 anonymized serum samples per 10-year age group based on convenience sampling. We measured levels of antibody against the pandemic virus by hemagglutination inhibition and microneutralization assays. We assessed geometric mean titres and the proportion of people with seroprotective antibody levels (hemagglutination inhibition titre ≥ 40). We performed sensitivity analyses to evaluate titre thresholds of 80, 20 and 10. Results: Serum samples from 1127 people aged 9 months to 101 years were obtained. The overall age-standardized proportion of people with seroprotective antibody levels was 46%. A U-shaped age distribution was identified regardless of assay or titre threshold applied. Among those less than 20 years old and those 80 years and older, the prevalence of seroprotection was comparably high at about 70%. Seroprotection was 44% among those aged 20–49 and 30% among those 50–79 years. It was lowest among people aged 70–79 years (21%) and highest among those 90 years and older (88%). Interpretation: We measured much higher levels of seroprotection after the 2009 pandemic compared than before the pandemic, with a U-shaped age distribution now evident. These findings, particularly the low levels of seroprotection among people aged 50–79 years, should be confirmed in other settings and closer to the influenza season.
- Published
- 2010
25. The effect of Echinacea purpurea, Astragalus membranaceus and Glycyrrhiza glabra on CD69 expression and immune cell activation in humans
- Author
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Alena G. Guggenheim, Julie Brush, Heather Zwickey, Randal Buresh, Amala Soumyanath, Erin Connelly, Elissa Mendenhall, Tracy Chan, and Richard Barrett
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Adult ,Antigens, Differentiation, T-Lymphocyte ,CD4-Positive T-Lymphocytes ,Male ,Adolescent ,Pharmacognosy ,CD8-Positive T-Lymphocytes ,Lymphocyte Activation ,complex mixtures ,Echinacea ,Immune system ,Antigen ,Adjuvants, Immunologic ,Antigens, CD ,Glycyrrhiza ,Cytotoxic T cell ,Humans ,Lectins, C-Type ,Aged ,Pharmacology ,Plants, Medicinal ,biology ,Traditional medicine ,Plant Extracts ,Astragalus Plant ,Middle Aged ,biology.organism_classification ,Astragalus ,Drug Therapy, Combination ,Female ,Cell activation - Abstract
The increasing use of medicinal herbs among the general public has piqued the need for scientific-based research to determine the mechanism of action of herbs administered orally in human subjects. The ability of three herbs, Echinacea purpurea, Astragalus membranaceus and Glycyrrhiza glabra, to activate immune cells in human subjects was assessed in this pilot study. The effect of these herbs when ingested for 7 days was measured both when administered singly, and in combination, using flow cytometry. The primary cell activation marker measured was CD69. The results demonstrate that Echinacea, Astragalus and Glycyrrhiza herbal tinctures stimulated immune cells as quantified by CD69 expression on CD4 and CD8 T cells. This activation took place within 24 h of ingestion, and continued for at least 7 days. In addition, these three herbs had an additive effect on CD69 expression when used in combination.
- Published
- 2006
26. Isha Yoga Practices and Participation in Samyama Program are Associated with Reduced HbA1C and Systemic Inflammation, Improved Lipid Profile, and Short-Term and Sustained Improvement in Mental Health: A Prospective Observational Study of Meditators
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Senthilkumar Sadhasivam, Suresh Alankar, Raj Maturi, Amy Williams, Ramana V. Vishnubhotla, Sepideh Hariri, Mayur Mudigonda, Dhanashri Pawale, Sangeeth Dubbireddi, Senthil Packiasabapathy, Peter Castelluccio, Chithra Ram, Janelle Renschler, Tracy Chang, and Balachundhar Subramaniam
- Subjects
meditation ,depression ,anxiety ,biomarkers ,Isha ,Samyama ,Psychology ,BF1-990 - Abstract
Background: Meditation is gaining recognition as a tool to impact health and well-being. Samyama is an 8-day intensive residential meditation experience conducted by Isha Foundation requiring several months of extensive preparation and vegan diet. The health effects of Samyama have not been previously studied. The objective was to assess physical and emotional well-being before and after Samyama participation by evaluating psychological surveys and objective health biomarkers.Methods: This was an observational study of 632 adults before and after the Isha Samyama retreat. All participants were invited to complete surveys. Controls included household significant others. Surveys were completed at baseline (T1), just before Samyama (T2), immediately after Samyama (T3), and 3 months later (T4) to assess anxiety, depression, mindfulness, joy, vitality, and resilience through validated psychometric scales. Voluntary blood sampling for biomarker analysis was done to assess hemoglobin (Hb), HbA1c, lipid profile, and C-reactive protein (CRP). Primary outcomes were changes in psychometric scores, body weight, and blood biomarkers.Results: Depression and anxiety scores decreased from T1 to T3, with the effect most pronounced in participants with baseline depression or anxiety. Scores at T4 remained below baseline for those with pre-existing depression or anxiety. Vitality, resilience, joy, and mindfulness increased from T1 to T3 (sustained at T4). Body weight decreased by 3% from T1 to T3. Triglycerides (TG) were lower from T2 to T3. Participants had lower HbA1c and HDL at T2, and lower CRP at all timepoints compared with controls.Conclusions: Participation in the Isha Samyama program led to multiple benefits. The 2-month preparation reduced anxiety, and participants maintained lower anxiety levels at 3 months post-retreat. Physical health improved over the course of the program as evidenced by weight loss and improved HbA1C and lipid profile. Practices associated with the Samyama preparation phase and the retreat may serve as an effective way to improve physical and mental health. Future studies may examine their use as an alternative therapy in patients with depression and/or anxiety.Clinical Trial Registration:www.ClinicalTrials.gov, Identifier: 1801728792. Registered retrospectively on 4/17/2020.
- Published
- 2021
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27. InnateDB & Cerebral: user‐friendly tools for the systems‐level analysis of innate immunity
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Geoffrey L. Winsor, Melissa Yau, Aaron Barsky, Jaimmie Que, Tracy Chan, Fiona S. L. Brinkman, Fiona M. Roche, David J. Lynn, D Tulpan, Michael Acab, Misbah Naseer, Raymond Lo, Robert E. W. Hancock, Matthew R. Laird, Calvin Chan, Jennifer L. Gardy, Tamara Munzner, Matthew D. Whiteside, Naisha Shah, and N Richard
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0303 health sciences ,03 medical and health sciences ,User Friendly ,0302 clinical medicine ,Innate immune system ,Human–computer interaction ,Computer science ,Genetics ,Molecular Biology ,Biochemistry ,030217 neurology & neurosurgery ,030304 developmental biology ,Biotechnology - Published
- 2008
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