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Ravindran S, Gubbay JB, Cronin K, Sullivan A, Zygmunt A, Johnson K, Buchan SA, Parpia AS. Association Between Cycle Threshold Value and Vaccination Status Among Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Cases in Ontario, Canada, in December 2021. Open Forum Infect Dis 2023; 10:ofad282. [PMID: 37274182 PMCID: PMC10234392 DOI: 10.1093/ofid/ofad282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 05/18/2023] [Indexed: 06/06/2023] Open
Abstract
Background Increased immune evasion by emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and occurrence of breakthrough infections raise questions about whether coronavirus disease 2019 vaccination status affects SARS-CoV-2 viral load among those infected. This study examined the relationship between cycle threshold (Ct) value, which is inversely associated with viral load, and vaccination status at the onset of the Omicron wave onset in Ontario, Canada. Methods Using linked provincial databases, we compared median Ct values across vaccination status among polymerase chain reaction-confirmed Omicron variant SARS-CoV-2 cases (sublineages B.1.1.529, BA.1, and BA.1.1) between 6 and 30 December 2021. Cases were presumed to be Omicron based on S-gene target failure. We estimated the relationship between vaccination status and Ct values using multiple linear regression, adjusting for age group, sex, and symptom status. Results Of the 27 029 presumed Omicron cases in Ontario, the majority were in individuals who had received a complete vaccine series (87.7%), followed by unvaccinated individuals (8.1%), and those who had received a booster dose (4.2%). The median Ct value for post-booster dose individuals (18.3 [interquartile range, 15.4-22.3]) was significantly higher than that for unvaccinated (17.9 [15.2-21.6]; P = .02) and post-vaccine series individuals (17.8 [15.3-21.5]; P = .005). Post-booster dose cases remained associated with a significantly higher median Ct value than cases in unvaccinated individuals (P ≤ .001), after adjustment for covariates. Compared with values in persons aged 18-29 years, Ct values were significantly lower among most age groups >50 years. Conclusions While slightly lower Ct values were observed among unvaccinated individuals infected with Omicron compared with post-booster dose cases, further research is required to determine whether a significant difference in secondary transmission exists between these groups.
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Affiliation(s)
| | - Jonathan B Gubbay
- Public Health Ontario Laboratory, Public Health Ontario, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology and Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Kirby Cronin
- Public Health Ontario Laboratory, Public Health Ontario, Toronto, Ontario, Canada
| | - Ashleigh Sullivan
- Public Health Ontario Laboratory, Public Health Ontario, Toronto, Ontario, Canada
| | - Austin Zygmunt
- Health Protection, Public Health Ontario, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology and Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Karen Johnson
- Health Protection, Public Health Ontario, Toronto, Ontario, Canada
| | - Sarah A Buchan
- Correspondence: Sarah A. Buchan, Public Health Ontario, 661 University Ave, Floor 17, Toronto, ON M5G 1M1, Canada (); Alyssa S. Parpia, Public Health Ontario, 480 University Ave, Toronto, ON M5G 1V2, Canada ()
| | - Alyssa S Parpia
- Correspondence: Sarah A. Buchan, Public Health Ontario, 661 University Ave, Floor 17, Toronto, ON M5G 1M1, Canada (); Alyssa S. Parpia, Public Health Ontario, 480 University Ave, Toronto, ON M5G 1V2, Canada ()
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Mahendra Raj S, Ravindran S, Kaur M, Braganza MC, Kunnath AP. Duodenal eosinophilia is associated with symptomatic erosive gastro-oesophageal reflux disease, presence of co-morbidities, and ethnicity but not undifferentiated functional dyspepsia: A retrospective Malaysian study. Med J Malaysia 2022; 77:494-499. [PMID: 35902941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
BACKGROUND Duodenal eosinophilia is postulated to play a key role in the pathogenesis of functional dyspepsia, a common condition responsible for considerable impairment of quality of life. Our objective was to evaluate the relative strength of the associations between duodenal eosinophilia, functional dyspepsia, symptomatic erosive gastroesophageal reflux disease (GERD), the presence of co-morbidities, and a number of other variables. METHODS Eosinophil counts of archived endoscopic duodenal biopsies of 289 subjects were determined by a pathologist blinded to the clinical data. Duodenal eosinophilia was defined by a count of more than 15 per 5 high power fields. Clinical charts were reviewed by a gastroenterologist blinded to the histology review. RESULTS In the study sample, the primary diagnosis was functional dyspepsia (undifferentiated by subtypes) in 45, symptomatic erosive GERD in 29, gall stone disease in 17, irritable bowel syndrome in 23, and an alternative or undetermined diagnosis in 175 subjects, respectively. On logistic regression analyses, eosinophil counts were positively associated with symptomatic erosive GERD (Odds Ratio, OR 1.03, 95% Confidence Interval, 95%CI: 1.00, 1.05; p=0.035) but not functional dyspepsia. Pre-defined duodenal eosinophilia was associated with symptomatic erosive gastro-oesophageal reflux disease (OR 3.36, 95%CI 1.18,-9.60; p=0.023), the presence of co-morbidities (OR 2.00, 95%CI 1.10, 3.62; p=0.022), and Chinese (as compared to Malay and Indian) ethnicity but not with either functional dyspepsia, irritable bowel syndrome, gallstone disease, Helicobacter pylori infection, or gender. CONCLUSION Duodenal eosinophilia was associated with symptomatic erosive GERD, the presence of co-morbidities, and Chinese ethnicity but not with undifferentiated functional dyspepsia.
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Affiliation(s)
- S Mahendra Raj
- Pantai Hospital Kuala Lumpur, Department of Medicine, Kuala Lumpur Malaysia.
| | - S Ravindran
- Pantai Hospital Kuala Lumpur, Pantai Premier Pathology, Kuala Lumpur Malaysia
| | - M Kaur
- International Medical University, School of Health Sciences, Division of Applied Biomedical Science and Biotechnology, Bukit Jalil, Kuala Lumpur, Malaysia
| | - M C Braganza
- International Medical University, School of Health Sciences, Division of Applied Biomedical Science and Biotechnology, Bukit Jalil, Kuala Lumpur, Malaysia
| | - A P Kunnath
- International Medical University, School of Health Sciences, Division of Applied Biomedical Science and Biotechnology, Bukit Jalil, Kuala Lumpur, Malaysia
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Dennis CL, Carsley S, Brennenstuhl S, Brown HK, Marini F, Bell RC, Miller A, Ravindran S, D’Paiva V, Dol J, Birken CS. Screen use and internet addiction among parents of young children: A nationwide Canadian cross-sectional survey. PLoS One 2022; 17:e0257831. [PMID: 35100281 PMCID: PMC8803162 DOI: 10.1371/journal.pone.0257831] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 09/12/2021] [Indexed: 11/19/2022] Open
Abstract
Objectives
To establish the factorial structure and internal consistency of the Internet Addiction Test (IAT) in parents, the level and correlates of problematic internet use, and patterns and types of screen use.
Study design
Data were collected through an online questionnaire about preconception health among Canadian women and men with ≥1 child. The questionnaire included the IAT and questions about time spent on screens by device type, use of screens during meals and in the bedroom, and perceptions of overuse. Factor analysis was completed to determine the factorial structure of the IAT, with multivariable linear regression used to determine correlates of the IAT.
Results
The sample included 1,156 respondents (mean age: 34.3 years; 83.1% female). The IAT had two factors: “impairment in time management” and “impairment in socio-emotional functioning” of which respondents had more impairment in time management than socio-emotional functioning. Based on the original IAT, 19.4% of respondents would be classified as having a mild internet use problem with 3.0% having a moderate or severe issue. In the multivariable model, perceived stress (b = .28, SE = .05, p < .001) and depressive symptoms (b = .24, SE = .10, p = .017) were associated with higher IAT scores. Handheld mobile devices were the most common type of screen used (mean = 3 hours/day) followed by watching television (mean = 2 hours/day).
Conclusion
Parents spent a significant portion of their time each day using screens, particularly handheld mobile devices. The disruption caused by mobile devices may hinder opportunities for positive parent-child interactions, demonstrating the need for resources to support parents ever-growing use of technologies.
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Affiliation(s)
- Cindy-Lee Dennis
- Lawrence S. Bloomberg Faculty of Nursing, University of Toronto, Toronto, Canada
- Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
- * E-mail:
| | - Sarah Carsley
- Public Health Ontario, Toronto, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
| | - Sarah Brennenstuhl
- Lawrence S. Bloomberg Faculty of Nursing, University of Toronto, Toronto, Canada
| | - Hilary K. Brown
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
- Interdisciplinary Centre for Health & Society, University of Toronto Scarborough, Toronto, Canada
| | - Flavia Marini
- Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada
| | - Rhonda C. Bell
- Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, Canada
| | | | | | | | - Justine Dol
- Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada
| | - Catherine S. Birken
- Faculty of Medicine, University of Toronto, Toronto, Canada
- Hospital for Sick Children, Toronto, Canada
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Mahendra Raj S, Ravindran S, Braganza MC, Kaur K, Kunnath AP. A retrospective audit of endoscopic duodenal biopsies to uncover undetected Coeliac disease in Malaysian patients. Med J Malaysia 2021; 76:811-813. [PMID: 34806665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
BACKGROUND Coeliac disease, an autoimmune enteropathy related to gluten sensitivity was hitherto thought to be rare in Asia. Recent data however suggests that Celiac disease may be under-diagnosed in Asia. OBJECTIVE The aim of this audit was to determine the frequency of histological changes compatible with Coeliac disease among patients undergoing elective diagnostic oesaphago-gastro-duodenoscopy (OGDS) under the care of a single practitioner in a Malaysian hospital. MATERIALS AND METHODS The archived endoscopically obtained duodenal biopsy specimens of 241 consecutive Malaysian subjects undergoing elective diagnostic (OGDS) were reviewed by a pathologist blinded to the clinical data. Based on intra-epithelial lymphocyte counts, crypt hyperplasia and villous atrophy, each subject was assigned to one of the categories of the Modified Marsh classification for the histological diagnosis of Coeliac disease. The clinical charts of all subjects were reviewed by a single gastroenterologist blinded to the findings of the histological review. RESULTS Of the 241 study subjects, 132 (54.8%) were females. There were 56 (23.2%) Malays, 90 (37.3%) Chinese, 88 (36.5%) Indians and seven (2.9%) from the other category. The median age of the study sample was 49 years (range 15- 88 years). The OGDS was done as part of screening in 15(6.2%) subjects while in the remaining it was part of the investigation of a clinical problem. Based on histological findings, none of the subjects could be assigned to a modified Marsh class of >1. The prevalence of histological changes compatible with Coeliac disease in the study was 0% (binomial exact one-sided 97.5 % confidence interval 0- 1.52%). CONCLUSION In conclusion, this audit provides no evidence that active Coeliac disease is significantly under-detected among symptomatic patients presenting for diagnostic OGDS. The possibility that a significant number may have potential coeliac disease cannot be excluded.
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Affiliation(s)
- S Mahendra Raj
- Pantai Hospital Kuala Lumpur, Department of Medicine, Malaysia.
| | - S Ravindran
- Pantai Hospital Kuala Lumpur, Pantai Premier Pathology, Malaysia
| | - M C Braganza
- International Medical University, School of Health Sciences, Division of Applied Biomedical Science and Biotechnology, Bukit Jalil, Kuala Lumpur, Malaysia
| | - K Kaur
- International Medical University, School of Health Sciences, Division of Applied Biomedical Science and Biotechnology, Bukit Jalil, Kuala Lumpur, Malaysia
| | - A P Kunnath
- International Medical University, School of Health Sciences, Division of Applied Biomedical Science and Biotechnology, Bukit Jalil, Kuala Lumpur, Malaysia
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Murti M, Achonu C, Smith BT, Brown KA, Kim JH, Johnson J, Ravindran S, Buchan SA. COVID-19 Workplace Outbreaks by Industry Sector and Their Associated Household Transmission, Ontario, Canada, January to June, 2020. J Occup Environ Med 2021; 63:574-580. [PMID: 33950040 PMCID: PMC8247533 DOI: 10.1097/jom.0000000000002201] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE To analyze workplace outbreaks by industry sector in the first wave of the pandemic, and associated household cases. METHODS Number, size, and duration of outbreaks were described by sector, and outbreak cases were compared to sporadic cases in the same time frame. Address matching identified household cases with onset ≥2 days before, ≥2 days after, or within 1 day of the workplace outbreak case. RESULTS There were 199 outbreaks with 1245 cases, and 68% of outbreaks and 80% of cases belonged to (1) Manufacturing, (2) Agriculture, Forestry, Fishing, Hunting, (3) Transportation and Warehousing. There were 608 household cases associated with 339 (31%) outbreak cases, increasing the burden of illness by 56%. CONCLUSIONS Workplace outbreaks primarily occurred in three sectors. Prevention measures should target industry sectors at risk to prevent spread in and out of the workplace.
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Affiliation(s)
- Michelle Murti
- Public Health Ontario, Toronto, Ontario, Canada (Dr Murti, Ms Achonu, Dr Smith, Dr Brown, Dr Kim, Mr Johnson, Ms Ravindran, and Dr Buchan); Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada (Dr Murti, Dr Smith, Dr Kim, and Dr Buchan)
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Ravindran S, Yoganathan S, Cairncross ZF, Dennis CL, Enders J, Graves L, Mill C, Telner D, Brown HK. Pilot Randomized Controlled Trial of an Interconception Intervention Provided by Public Health Nurses. Matern Child Health J 2020; 24:1161-1169. [PMID: 32656692 DOI: 10.1007/s10995-020-02980-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Preconception health impacts perinatal outcomes, but the difficulty in engaging reproductive-aged individuals in health promotion activities is a barrier to effective implementation of preconception interventions. Since most women have more than one pregnancy and many risk factors repeat across pregnancies, the time between pregnancies-the interconception period-may be an opportune time to improve health. Our objective was to examine the feasibility and acceptability of an interconception intervention delivered by public health nurses. METHODS We conducted a pilot randomized controlled trial in three small urban and rural public health units in Ontario, Canada, in 2017-2018 among women who were ≥ 18 years of age and between 2 and 12 months postpartum after a first birth. Women randomly allocated to the intervention group received a preconception risk assessment, tailored health education, and referral for clinical follow-up as needed, while those in the control group received standard care. Primary outcomes were intervention feasibility, adherence, and acceptability. RESULTS Of 66 eligible women, 61% agreed to participate and were randomized to the intervention (n = 16) or control (n = 24) groups. The follow-up rate was 78% at 1 month and 71% at 3 months. Most women (83%) were satisfied with the intervention, including the number and length of sessions and content of recommendations. CONCLUSIONS FOR PRACTICE Results demonstrate the potential feasibility and acceptability of an interconception intervention delivered in a public health setting. The short- and long-term impacts of the intervention on knowledge, behavior, and health should be tested in a larger sample.
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Affiliation(s)
- Saranyah Ravindran
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
| | - Shaira Yoganathan
- Interdisciplinary Centre for Health & Society, University of Toronto Scarborough, Toronto, ON, Canada
| | - Zoe F Cairncross
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
| | - Cindy-Lee Dennis
- Women's College Research Institute, Women's College Hospital, Toronto, ON, Canada
- Lawrence S. Bloomberg Faculty of Nursing, University of Toronto, Toronto, ON, Canada
- Department of Psychiatry, Faculty of Medicine, Toronto, ON, Canada
- Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
| | - Joanne Enders
- Ontario Public Health Association, Toronto, ON, Canada
| | - Lisa Graves
- Department of Family and Community Medicine, Western Michigan University Homer Stryker M.D. School of Medicine, Kalamazoo, MI, USA
| | - Catriona Mill
- Ontario Public Health Association, Toronto, ON, Canada
- Toronto Public Health, Toronto, ON, Canada
| | - Deanna Telner
- Department of Family and Community Medicine, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Hilary K Brown
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.
- Interdisciplinary Centre for Health & Society, University of Toronto Scarborough, Toronto, ON, Canada.
- Women's College Research Institute, Women's College Hospital, Toronto, ON, Canada.
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Cairncross Z, Dennis CL, Brennenstuhl S, Ravindran S, Enders J, Graves L, Mill C, Telner D, Brown HK. Development and Psychometric Evaluation of the Preconception Health Knowledge Questionnaire. Am J Health Promot 2020; 35:172-178. [PMID: 32757832 DOI: 10.1177/0890117120946682] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To develop and psychometrically test a comprehensive measure of preconception health knowledge. DESIGN Cross-sectional survey, in May and June, 2019. SETTING Alberta, Ontario, and Québec, Canada. SAMPLE One thousand seven hundred seventy-seven women and men with ≥1 children born in the last 5 years or planning a pregnancy in the next 5 years. MEASURES Using prior literature and input from public health nurses and physicians, the Preconception Health Knowledge Questionnaire (PHKQ) was developed and comprised 25 multiple choice questions on reproductive history, sexual health, infectious diseases, chronic medical conditions, mental health, medications, immunizations, lifestyle behaviors, psychosocial stressors, and environmental exposures. ANALYSIS Psychometric testing was undertaken to evaluate item difficulty, discrimination, quality of response alternatives, internal consistency, and construct validity. RESULTS Participants had a mean total score of 15.8/25 (SD = 3.9); women and men had mean total scores of 16.2 (SD = 3.6) and 13.8 (SD = 4.7), respectively. Most items were neither too difficult nor too easy, discriminated well between participants with high and low knowledge, and had appropriate response alternatives. High internal consistency (KR-20 = 0.87) and construct validity, shown via significant correlations with education level and previous preconception care receipt, were demonstrated. CONCLUSION The PHKQ is a reliable and valid tool for measuring preconception health knowledge and may be useful in identification of high-risk groups in need of preconception health education and evaluation of preconception health interventions.
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Affiliation(s)
- Zoe Cairncross
- 274071Dalla Lana School of Public Health, Toronto, Ontario, Canada
| | - Cindy-Lee Dennis
- Lawrence S. Bloomberg Faculty of Nursing, 7938University of Toronto , Toronto, Ontario, Canada.,Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.,Department of Psychiatry, Faculty of Medicine, 4175University of Toronto, Toronto, Ontario, Canada
| | - Sarah Brennenstuhl
- Lawrence S. Bloomberg Faculty of Nursing, 7938University of Toronto , Toronto, Ontario, Canada
| | | | - Joanne Enders
- Ontario Public Health Association, Toronto, Ontario, Canada
| | - Lisa Graves
- Department of Family and Community Medicine, Homer Stryker M.D. School of Medicine, Western Michigan University, Kalamazoo, MI, USA
| | - Catriona Mill
- Ontario Public Health Association, Toronto, Ontario, Canada.,7986Toronto Public Health, Toronto, Ontario, Canada
| | - Deanna Telner
- Department of Family and Community Medicine, Faculty of Medicine, 7938University of Toronto, Toronto, Ontario, Canada
| | - Hilary K Brown
- 274071Dalla Lana School of Public Health, Toronto, Ontario, Canada.,Interdisciplinary Centre for Health & Society, 7938University of Toronto Scarborough, Toronto, Ontario, Canada.,Women's College Research Institute, Women's College Hospital, Toronto, Ontario, Canada
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Cairncross ZF, Ravindran S, Yoganathan S, Dennis CL, Enders J, Graves L, Mill C, Telner D, Brown HK. Measurement of Preconception Health Knowledge: A Systematic Review. Am J Health Promot 2019; 33:941-954. [DOI: 10.1177/0890117119835518] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective: Preconception health is an important determinant of maternal, paternal, and infant outcomes. Knowledge is commonly used to evaluate the effectiveness of interventions to promote preconception health. Our objective was to examine how preconception health knowledge has been measured in the existing literature and to identify measurement gaps, biases, and logistical challenges. Data Source: MEDLINE, EMBASE, PsycINFO, CINAHL, the Cochrane Database of Systematic Reviews, and gray literature were searched from database inception to January 2018. Study Inclusion and Exclusion Criteria: Studies were included if they measured preconception or interconception health knowledge and included reproductive-aged women and/or men. Data Extraction: Two independent reviewers completed data extraction and quality appraisal using standardized instruments. Data Synthesis: Due to measurement heterogeneity, a narrative synthesis was performed. Results: The review included 34 studies from 14 countries with data collected in 2000 to 2017. Most studies used cross-sectional (n = 24) or prepost designs (n = 7). Studies primarily sampled women (n = 25), and methodological quality was rated largely as weak (n = 18) or moderate (n = 14). Preconception health knowledge tools focused on fertility, folic acid, and alcohol, with few questions pertaining to men’s health, mental health, or the interconception period. Only 19 (56%) studies reported psychometric properties of their knowledge tools. Conclusions: This systematic review revealed the need for a valid and reliable knowledge tool that reflects a holistic conceptualization of preconception health.
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Affiliation(s)
- Zoe F. Cairncross
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Saranyah Ravindran
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Shaira Yoganathan
- Interdisciplinary Centre for Health & Society, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Cindy-Lee Dennis
- Women’s College Research Institute, Women’s College Hospital, Toronto, Ontario, Canada
- Lawrence S. Bloomberg Faculty of Nursing, University of Toronto, Toronto, Ontario, Canada
- Department of Psychiatry, Faculty of Medicine, Toronto, Ontario, Canada
- Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Ontario, Canada
| | - Joanne Enders
- Ontario Public Health Association Reproductive Health Workgroup, Toronto, Ontario, Canada
| | - Lisa Graves
- Department of Family and Community Medicine, Western Michigan University Homer Stryker M.D. School of Medicine, Kalamazoo, MI, USA
| | - Catriona Mill
- Ontario Public Health Association Reproductive Health Workgroup, Toronto, Ontario, Canada
- Toronto Public Health, Toronto, Ontario, Canada
| | - Deanna Telner
- Department of Family and Community Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Hilary K. Brown
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
- Interdisciplinary Centre for Health & Society, University of Toronto Scarborough, Toronto, Ontario, Canada
- Women’s College Research Institute, Women’s College Hospital, Toronto, Ontario, Canada
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Ravindran S, Williams M, Ward R, Gillies G. Understanding how the properties of whey protein stabilized emulsions depend on pH, ionic strength and calcium concentration, by mapping environmental conditions to zeta potential. Food Hydrocoll 2018. [DOI: 10.1016/j.foodhyd.2017.12.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Ravindran S, Melvani V, Tobin M. P108 Chronic urticaria in the presence of papillary thyroid cancer. Ann Allergy Asthma Immunol 2016. [DOI: 10.1016/j.anai.2016.09.118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Liong CC, Ravindran S, Gnana Kumar G, Chin EF, Koh PS, Chan WK. Enteropathy-associated T-cell lymphoma: An extremely rare cause of chronic diarrhoea. Med J Malaysia 2016; 71:88-90. [PMID: 27326953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Chronic diarrhoea in tropical countries may be due to a myriad of causes from infective to non-infective. This case report illustrates the challenges faced in the investigation of a middle-age Chinese gentleman who presented with chronic diarrhoea and weight loss. The diagnosis of type II enteropathy-associated T-cell lymphoma (EATL) was finally made. The diagnosis of EATL was least suspected as the condition is almost unheard of in this part of the world. The epidemiology, presentation, diagnosis, management and prognosis of this rare condition are discussed.
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Affiliation(s)
- C C Liong
- University of Malaya, Faculty of Medicine, Department of Medicine, Gastroenterology and Hepatology Unit, Kuala Lumpur, Malaysia.
| | - S Ravindran
- University of Malaya, Faculty of Medicine, Department of Pathology, Kuala Lumpur, Malaysia
| | - G Gnana Kumar
- University of Malaya, Faculty of Medicine, Department of Biomedical Imaging, Kuala Lumpur, Malaysia
| | - E F Chin
- University of Malaya, Faculty of Medicine, Department of Medicine, Hematology Unit, Kuala Lumpur, Malaysia
| | - P S Koh
- University of Malaya, Faculty of Medicine, Department of Surgery, Kuala Lumpur, Malaysia
| | - W K Chan
- University of Malaya, Faculty of Medicine, Department of Medicine, Gastroenterology and Hepatology Unit, Kuala Lumpur, Malaysia
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Ravindran S, Tessema A, Kidane A. Note: Dynamic meso-scale full field surface deformation measurement of heterogeneous materials. Rev Sci Instrum 2016; 87:036108. [PMID: 27036841 DOI: 10.1063/1.4944488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 03/06/2016] [Indexed: 06/05/2023]
Abstract
A dynamic experiment at mesoscale is developed to measure local deformation and strain in granular materials at high temporal and spatial resolutions. The experimental setup is comprised of a high-speed camera along with a high magnification extension tube. The method is demonstrated by measuring the full field strain across and in the boundary of the crystals at a high temporal resolution in polymer bonded sugar crystals and glass beads filled epoxy particulate composite specimens under dynamic loading. In both cases, the local strain heterogeneity is captured successfully. The measured strain and deformation field can be further used to obtain the relative motion of each crystal, crystal rotation, and the relative displacement between the polymer interface and the crystal, which are very critical to understand the local failure mechanisms in heterogeneous materials.
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Affiliation(s)
- S Ravindran
- Department of Mechanical Engineering, the University of South Carolina, Columbia, South Carolina 28209, USA
| | - A Tessema
- Department of Mechanical Engineering, the University of South Carolina, Columbia, South Carolina 28209, USA
| | - A Kidane
- Department of Mechanical Engineering, the University of South Carolina, Columbia, South Carolina 28209, USA
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Padovano JD, Ravindran S, Snee PT, Ramachandran A, Bedran-Russo AK, George A. DMP1-derived peptides promote remineralization of human dentin. J Dent Res 2015; 94:608-14. [PMID: 25694469 DOI: 10.1177/0022034515572441] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Remineralization of dentin during dental caries is of considerable clinical interest. Dentin matrix protein 1 (DMP1) is a non-collagenous calcium-binding protein that plays a critical role in biomineralization. In the present study, we tested if peptides derived from DMP1 can be used for dentin remineralization. Peptide pA (pA, MW = 1.726 kDa) and peptide pB (pB, MW = 2.185), containing common collagen-binding domains and unique calcium-binding domains, were synthesized by solid-phase chemistry. An extreme caries lesion scenario was created by collagenase digestion, and the biomineral-nucleating potential of these peptides was ascertained when coated on collagenase-treated dentin matrix and control, native human dentin matrix under physiological levels of calcium and phosphate. Scanning electron microscopy analysis suggests that peptide pB was an effective nucleator when compared with pA. However, a 1:4 ratio of pA to pB was determined to be ideal for dentin remineralization, based on hydroxyapatite (HA) morphology and calcium/phosphorus ratios. Interestingly, HA was nucleated on collagenase-challenged dentin with as little as 20 min of 1:4 peptide incubation. Electron diffraction confirmed the presence of large HA crystals that produced a diffraction pattern indicative of a rod-like crystal structure. These findings suggest that DMP1-derived peptides may be useful to modulate mineral deposition and subsequent formation of HA when exposed to physiological concentrations of calcium and phosphate.
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Affiliation(s)
- J D Padovano
- Brodie Tooth Development Genetics & Regenerative Medicine Research Laboratory, Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - S Ravindran
- Brodie Tooth Development Genetics & Regenerative Medicine Research Laboratory, Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - P T Snee
- Department of Chemistry, College of Liberal Arts and Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - A Ramachandran
- Brodie Tooth Development Genetics & Regenerative Medicine Research Laboratory, Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - A K Bedran-Russo
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, Chicago, IL, USA
| | - A George
- Brodie Tooth Development Genetics & Regenerative Medicine Research Laboratory, Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
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Zhang Y, Song Y, Ravindran S, Gao Q, Huang CC, Ramachandran A, Kulkarni A, George A. DSPP contains an IRES element responsible for the translation of dentin phosphophoryn. J Dent Res 2013; 93:155-61. [PMID: 24352500 DOI: 10.1177/0022034513516631] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The major phosphoprotein in dentin is the aspartic acid and serine-rich protein called dentin phosphophoryn (DPP). DPP appears to be synthesized as a part of a larger compound protein, dentin sialophosphoprotein (DSPP). DSPP has never been isolated or detected in dentin extracts. It is now evident that DSPP is a chimeric protein composed of 3 parts: dentin sialoprotein (DSP), DPP, and dentin glycoprotein (DGP). Previous reports have suggested that the BMP1 protease is responsible for processing DSPP. However, unequal amounts of these products are present in the dentin matrix. Here, we provide evidence for an internal ribosome entry site in the DSPP gene that directs the synthesis of DPP. This mechanism would account for unequal amounts of intracellular DSP and DPP. The internal ribosomal entry site (IRES) activity varied in different cell types, suggesting the presence of additional regulatory elements during the translational regulation of DPP. Further, we provide evidence that DPP is transported to the extracellular matrix (ECM) through exosomes. Using tissue recombination and lentivirus-mediated gain-of-function approaches, we also demonstrate that DPP is essential for the formation of well-defined tooth structures with mineralized dentin matrix.
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Affiliation(s)
- Y Zhang
- Brodie Tooth Development Genetics & Regenerative Medicine Research Laboratory, Department of Oral Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
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Rao SPS, Lakshminarayana SB, Kondreddi RR, Herve M, Camacho LR, Bifani P, Kalapala SK, Jiricek J, Ma NL, Tan BH, Ng SH, Nanjundappa M, Ravindran S, Seah PG, Thayalan P, Lim SH, Lee BH, Goh A, Barnes WS, Chen Z, Gagaring K, Chatterjee AK, Pethe K, Kuhen K, Walker J, Feng G, Babu S, Zhang L, Blasco F, Beer D, Weaver M, Dartois V, Glynne R, Dick T, Smith PW, Diagana TT, Manjunatha UH. Indolcarboxamide Is a Preclinical Candidate for Treating Multidrug-Resistant Tuberculosis. Sci Transl Med 2013; 5:214ra168. [DOI: 10.1126/scitranslmed.3007355] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Padovano J, Ravindran S, Ramachandran A, Bedran-Russo A, George A. Dentin mineralization using DMP1-derived synthetic peptides. Dent Mater 2013. [DOI: 10.1016/j.dental.2013.08.194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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George A, Ramachandran A, Albazzaz M, Ravindran S. DMP1--a key regulator in mineralized matrix formation. J Musculoskelet Neuronal Interact 2007; 7:308. [PMID: 18094486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Affiliation(s)
- A George
- Department of Oral Biology, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
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Chadwick D, Pido-Lopez J, Pires A, Imami N, Gotch F, Villacian JS, Ravindran S, Paton NI. A pilot study of the safety and efficacy of thymosin alpha 1 in augmenting immune reconstitution in HIV-infected patients with low CD4 counts taking highly active antiretroviral therapy. Clin Exp Immunol 2004; 134:477-81. [PMID: 14632754 PMCID: PMC1808897 DOI: 10.1111/j.1365-2249.2003.02331.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
To study the safety and efficacy of thymosin alpha1 in stimulating immune reconstitution in combination with highly active antiretroviral therapy (HAART), a phase II randomized, controlled open-label trial of subcutaneous thymosin alpha1 was undertaken for 12 weeks. Twenty clinically stable patients with viral loads <400 copies/ml and CD4 counts less than 200 cells/microl were randomized to receive 3.2 mg thymosin alpha 1 subcutaneous injections twice weekly or no injections for 12 weeks. CD4 and CD8 counts, CD45 RO+ and RA+ subsets and signal joint T cell receptor excision circles (sjTREC) in peripheral blood mononuclear cells (PBMCs) were measured every 2 weeks. Thirteen patients received thymosin alpha 1 and seven were controls. Thymosin alpha 1 was well tolerated and there were no serious adverse events. There was no significant difference between the thymosin alpha1 and control groups in CD4, CD8 and CD45 lymphocyte subset changes at week 12; however, PBMC sjTREC levels increased significantly in the thymosin alpha 1-treated patients compared to controls at week 12. In conclusion, the increase in PBMC sjTREC levels in patients taking thymosin alpha1 may represent enhanced immune reconstitution; however, the clinical benefits and long-term consequences remain to be determined.
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Affiliation(s)
- D Chadwick
- Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore
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Abstract
C1-inhibitor is an important inhibitor of plasma kallikrein and C1, but also has inhibitory activity against numerous other plasma proteinases such as plasmin. The relevance of plasmin inhibition by the C1-inhibitor has been debated, with some evidence showing that plasmin causes significant proteolysis of C1-inhibitor. In the present study, we show that C1-inhibitor in its native state will inhibit plasmin without being significantly degraded, in a manner typical of all serpin reactions. However, if C1-inhibitor is in a denatured polymeric state (as can easily occur during storage, or as produced by heating of the native protein), it will be extensively degraded by plasmin. In addition, we show that hydrophobic interaction chromatography is an effective method to remove trace contaminants of inactive C1-inhibitor polymers.
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Affiliation(s)
- E W Brown
- Department of Oral Medicine and Diagnostic Sciences, and Center for Molecular Biology of Oral Diseases, University of Illinois at Chicago, 60612, USA
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Liu S, Gong X, Yan X, Peng T, Baker JC, Li L, Robben PM, Ravindran S, Andersson LA, Cole AB, Roche TE. Reaction Mechanism for Mammalian Pyruvate Dehydrogenase Using Natural Lipoyl Domain Substrates. Arch Biochem Biophys 2001; 386:123-35. [PMID: 11368334 DOI: 10.1006/abbi.2000.2222] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The pyruvate dehydrogenase (E1) component of the pyruvate dehydrogenase complex (PDC) catalyzes a two-step reaction. Recombinant production of substrate amounts of the lipoyl domains of the dihydrolipoyl transacetylase (E2) component of the mammalian PDC allowed kinetic characterization of the rapid physiological reaction catalyzed by E1. Using either the N-terminal (L1) or the internal (L2) lipoyl domain of E2 as a substrate, analyses of steady state kinetic data support a ping pong mechanism. Using standard E1 preparations, Michaelis constants (Km) were 52 +/- 14 microM for L1 and 24.8 +/- 3.8 microM for pyruvate and k(cat) was 26.3 s(-1). With less common, higher activity preparations of E1, the Km values were > or =160 microM for L1 and > or =35 microM for pyruvate and k(cat) was > or =70 s(-1). Similar results were found with the L2 domain. The best synthetic lipoylated-peptide (L2 residues 163-177) was a much poorer substrate (Km > or =15 mM, k(cat) approximately equals 5 s(-1); k(cat)/Km decreased >1,500-fold) than L1 or L2, but a far better substrate in the E1 reaction than free lipoamide (k(cat)/Km increased >500-fold). Each lipoate source was an effective substrate in the dihydrolipoyl dehydrogenase (E3) reaction, but E3 had a lower Km for the L2 domain than for lipoamide or the lipoylated peptides. In contrast to measurements with slow E1 model reactions that use artificial acceptors, we confirmed that the natural E1 reaction, using lipoyl domain acceptors, was completely inhibited (>99%) by phosphorylation of E1 and the phosphorylation strongly inhibited the reverse of the second step catalyzed by E1. The mechanisms by which phosphorylation interferes with E1 activity is interpreted based on accrued results and the location of phosphorylation sites mapped onto the 3-D structure of related alpha-keto acid dehydrogenases.
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Affiliation(s)
- S Liu
- Department of Biochemistry, Kansas State University, Manhattan 66506, USA
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Abstract
BACKGROUND Complete resection of a retroperitoneal sarcoma often requires removal of adjacent organs. In this study we evaluated the role of nephrectomy during operation for retroperitoneal sarcoma. METHODS Between July 1982 and July 1995, 75 of the 371 (20%) patients who underwent resection of retroperitoneal sarcoma at MSKCC underwent concommitant nephrectomy. Data concerning the reasons for nephrectomy, degree of sarcomatous renal involvement, and survival were retrospectively analyzed. RESULTS Fifty-four patients (72%) underwent nephrectomy during the initial resection, and 21 (28%) during a resection of a recurrent or persistent tumor. The most common reason for nephrectomy was total encasement by sarcoma (n = 40; 53%), followed by dense adherence of the tumor to the kidney (n = 21; 28%), and the direct invasion of the kidney by tumor (n = 2; 3%). Pathology demonstrated an absence of kidney invasion in the majority of cases (55 of 75; 73%). Renal capsular invasion was present in 11 of 75 (15%), renal parenchymal invasion in 7 of 75 (9%), and renal vein invasion in 2 of 75 (3%) of cases. There were no significant differences in survival based on degree of sarcoma involvement of the kidney, tumor grade, or whether the resection was for primary or recurrent disease. The 53 patients who underwent a complete gross resection of all tumor had a significantly improved long-term survival compared to the 20 patients who did not (50% versus 20% DFS at 5 years, respectively; p < 0.001). CONCLUSIONS Decisions for concomitant nephrectomy during resection of retroperitoneal sarcoma should be based on whether this maneuver will provide a complete resection of all gross tumor, in which case the long-term disease-free survival of 50% is comparable to the reported 5-year survival of all patients with retroperitoneal sarcoma who are completely resected.
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Affiliation(s)
- P Russo
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, New York 10021, USA
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du Preez J, Postma J, Ravindran S, van Brecht B. NITROGEN REAGENTS IN METAL ION SEPARATION. PART 6 2-(r-OCTYLTHIOMETHYL)PYRIDINE AS EXTRACTANT FOR LATER 3d TRANSITION METAL IONS. Solvent Extraction and Ion Exchange 1997. [DOI: 10.1080/07366299708934467] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Ravindran S, Radke GA, Guest JR, Roche TE. Lipoyl domain-based mechanism for the integrated feedback control of the pyruvate dehydrogenase complex by enhancement of pyruvate dehydrogenase kinase activity. J Biol Chem 1996; 271:653-62. [PMID: 8557670 DOI: 10.1074/jbc.271.2.653] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
To conserve carbohydrate reserves, the reaction of the pyruvate dehydrogenase complex (PDC) must be down-regulated when the citric acid cycle is provided sufficient acetyl-CoA. PDC activity is reduced primarily through increased phosphorylation of its pyruvate dehydrogenase (E1) component due to E1 kinase activity being markedly enhanced by elevated intramitochondrial NADH:NAD+ and acetyl-CoA:CoA ratios. A mechanism is evaluated in which enhanced kinase activity is facilitated by the build-up of the reduced and acetylated forms of the lipoyl moieties of the dihydrolipoyl acetyltransferase (E2) component through using NADH and acetyl-CoA in the reverse of the downstream reactions of the complex. Using a peptide substrate, kinase activity was stimulated by these products, ruling out the possibility kinase activity is increased due to changes in the reaction state of its substrate, E1 (thiamin pyrophosphate). Each E2 subunit contains two lipoyl domains, an NH2-terminal (L1) and the inward lipoyl domain (L2), which were individually produced in fully lipoylated forms by recombinant techniques. Although reduction and acetylation of the L1 domain or free lipoamide increased kinase activity, those modifications of the lipoate of the kinase-binding L2 domain gave much greater enhancements of kinase activity. The large stimulation of the kinase generated by acetyl-CoA only occurred upon addition of the transacetylase-catalyzing (lipoyl domain-free) inner core portion of E2 plus a reduced lipoate source, affirming that acetylation of this prosthetic group is an essential mechanistic step for acetyl-CoA enhancing kinase activity. Similarly, the lesser stimulation of kinase activity by just NADH required a lipoate source, supporting the need for lipoate reduction by E3 catalysis. Complete enzymatic delipoylation of PDC, the E2-kinase subcomplex, or recombinant L2 abolished the stimulatory effects of NADH and acetyl-CoA. Retention of a small portion of PDC lipoates lowered kinase activity but allowed stimulation of this residual kinase activity by these products. Reintroduction of lipoyl moieties, using lipoyl protein ligase, restored the capacity of the E2 core to support high kinase activity along with stimulation of that activity up to 3-fold by NADH and acetyl-CoA. As suggested by those results, the enhancement of kinase activity is very responsive to reductive acetylation with a half-maximal stimulation achieved with approximately 20% of free L2 acetylated and, from an analysis of previous results, with acetylation of only 3-6 of the 60 L2 domains in intact PDC. Based on these findings, we suggest that kinase stimulation results from modification of the lipoate of an L2 domain that becomes specifically engaged in binding the kinase. In conclusion, kinase activity is attenuated through a substantial range in response to modest changes in the proportion of oxidized, reduced, and acetylated lipoyl moieties of the L2 domain of E2 produced by fluctuations in the NADH:NAD+ and acetyl-CoA:CoA ratios as translated by the rapid and reversible E3 and E2 reactions.
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Affiliation(s)
- S Ravindran
- Department of Biochemistry, Kansas State University, Manhattan 66506, USA
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Natarajan VS, Ravindran S, Kailash K, Krishnaswamy B, Suresh B, Prabhu P. Assessment of nutrient intake and associated factors in an Indian elderly population. Age Ageing 1993; 22:103-8. [PMID: 8470555 DOI: 10.1093/ageing/22.2.103] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A group of 420 elderly people (163 women and 257 men with a mean age of 65 years) from urban and rural populations in India were selected for the study. The caloric intake of 93.3% was less than the recommended allowance, the mean daily caloric intake being 1191 kcal in men and 928 kcal in women. Except for calcium, all nutrients were deficient in their diet. Illiteracy (53%), lack of knowledge regarding daily allowances of nutrients (95%), poor economic background (46.7%), and breaking down of joint family system (63%) were possible associated factors examined.
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Affiliation(s)
- V S Natarajan
- Department of Geriatric Medicine, Government General Hospital, Madras, Tamil Nadu, India
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Radke GA, Ono K, Ravindran S, Roche TE. Critical role of a lipoyl cofactor of the dihydrolipoyl acetyltransferase in the binding and enhanced function of the pyruvate dehydrogenase kinase. Biochem Biophys Res Commun 1993; 190:982-91. [PMID: 8439347 DOI: 10.1006/bbrc.1993.1146] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Mammalian pyruvate dehydrogenase kinase binds to the lipoyl domain region of the core structure forming dihydrolipoyl acetyltransferase (E2) subunits. The bound kinase has a greatly enhanced rate in phosphorylating E2-bound pyruvate dehydrogenase (E1) tetramers versus the rate at which resolved kinase phosphorylates dissociated E1. This E2-activated kinase function was completely prevented by selective alkylation of reduced lipoyl groups while kinase and E1 binding to the E2 core were retained. Selective removal of lipoyl cofactors from intact E2 by treatment with Enterococcus faecalis lipoamidase decreased kinase activity by 4-fold and caused selective release of a major portion of the kinase from E2 in a sucrose-step gradient procedure. Selective and reversible modification of the lipoyl groups of E2 subunits also allowed the kinase to be dissociated under mildly chaotropic conditions. Thus, the lipoyl prosthetic group on one of the two lipoyl domains of E2 subunits is critically important for maintaining E2-activated kinase function and contributes to binding of the kinase to E2. Since removal of the lipoyl group weakened kinase binding to E2 more than modifying lipoyl thiols, it is suggested that the hydrophobic inner portion of the lipoyl conjugate (i.e., lysine carbons and C1 to C5 of the lipoic acid) is important in the binding of the kinase.
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Affiliation(s)
- G A Radke
- Department of Biochemistry, Kansas State University, Manhattan 66506
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Ravindran S. Confronting gender, poverty and powerlessness: an orientation programme for and by rural change agents. Community Dev J 1985; 20:213-221. [PMID: 12315293 DOI: 10.1093/cdj/20.3.213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Rajarajeswari G, Ravindran S, Radhakrishnan S, Viswanathan J. Embryonal rhabdomyosarcoma associated with maternal ingestion of stilboestrol. INDIAN J PATHOL MICR 1979; 22:185-8. [PMID: 489085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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