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Hasan M, Bidargaddi N, Muller K, Ramachandran J, Narayana S, Wigg AJ. Integrating smart phone applications in the management of cirrhotic patients: A scoping review. JGH Open 2023; 7:826-831. [PMID: 38162857 PMCID: PMC10757474 DOI: 10.1002/jgh3.13021] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 10/27/2023] [Accepted: 12/01/2023] [Indexed: 01/03/2024]
Abstract
Background and Aim Chronic liver disease and cirrhosis is a significant cause of healthcare utilization and patient morbidity and mortality worldwide. Smartphone applications have high uptake in most communities and therefore have great potential to provide remote support solutions to this patient population. The aim of this scoping review was therefore to provide a comprehensive overview using narrative synthesis on the use of smartphone-application-based digital interventions in cirrhotic populations. Materials and Methods PRISMA guidelines were followed, with two independent researchers identifying 10 relevant studies. Patients studied were predominantly those with decompensated cirrhosis, and hepatic encephalopathy was the most common complication studied. Results Smartphones were the most common platform used, but training periods, prior to commencement of the study, were rarely offered. Patient engagement rates with the technology were reported only in three studies, but all reported high (>50%) rates of engagement. Only one study examined the clinical effects of their digital intervention, with a 38% reduction in readmission rate reported. Conclusion Overall, the use of smartphone apps in cirrhosis is in an early phase of development and evaluation but preliminary studies suggest significant potential as an adjunct to routine medical care. Further high-quality studies of well-designed digital interventions are needed to advance this promising early experience.
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Affiliation(s)
- Mohamed Hasan
- Hepatology and Liver Transplantation Medicine UnitSouthern Adelaide Local Health NetworkBedford ParkSouth AustraliaAustralia
| | - Niranjan Bidargaddi
- College of Medicine and Public HealthFlinders University of South AustraliaBedford ParkSouth AustraliaAustralia
| | - Kate Muller
- Hepatology and Liver Transplantation Medicine UnitSouthern Adelaide Local Health NetworkBedford ParkSouth AustraliaAustralia
- College of Medicine and Public HealthFlinders University of South AustraliaBedford ParkSouth AustraliaAustralia
| | - Jeyamani Ramachandran
- Hepatology and Liver Transplantation Medicine UnitSouthern Adelaide Local Health NetworkBedford ParkSouth AustraliaAustralia
- College of Medicine and Public HealthFlinders University of South AustraliaBedford ParkSouth AustraliaAustralia
| | - Sumudu Narayana
- Hepatology and Liver Transplantation Medicine UnitSouthern Adelaide Local Health NetworkBedford ParkSouth AustraliaAustralia
| | - Alan J Wigg
- Hepatology and Liver Transplantation Medicine UnitSouthern Adelaide Local Health NetworkBedford ParkSouth AustraliaAustralia
- College of Medicine and Public HealthFlinders University of South AustraliaBedford ParkSouth AustraliaAustralia
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Loo KF, Woodman RJ, Bogatic D, Chandran V, Muller K, Chinnaratha MA, Bate J, Campbell K, Maddison M, Narayana S, Le H, Pryor D, Wigg A. High rates of treatment stage migration for early hepatocellular carcinoma and association with adverse outcomes: An Australian multicenter study. JGH Open 2022; 6:599-606. [PMID: 36091321 PMCID: PMC9446396 DOI: 10.1002/jgh3.12793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 06/15/2022] [Accepted: 07/04/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Kee Fong Loo
- Hepatology and Liver Transplant Medicine Unit Southern Adelaide Local Health Network Adelaide South Australia Australia
- College of Medicine and Public Health Flinders University Adelaide South Australia Australia
| | - Richard J Woodman
- College of Medicine and Public Health Flinders University Adelaide South Australia Australia
| | - Damjana Bogatic
- Department of Medicine Royal Adelaide Hospital Adelaide South Australia Australia
| | - Vidyaleha Chandran
- Department of Gastroenterology and Hepatology Lyell McEwin Hospital Adelaide South Australia Australia
| | - Kate Muller
- Hepatology and Liver Transplant Medicine Unit Southern Adelaide Local Health Network Adelaide South Australia Australia
- College of Medicine and Public Health Flinders University Adelaide South Australia Australia
| | - Mohamed Asif Chinnaratha
- Department of Gastroenterology and Hepatology Lyell McEwin Hospital Adelaide South Australia Australia
- Faculty of Health and Medical Sciences The University of Adelaide Adelaide South Australia Australia
| | - John Bate
- Department of Gastroenterology and Hepatology Royal Adelaide Hospital Adelaide South Australia Australia
| | - Kirsty Campbell
- Department of Gastroenterology and Hepatology Royal Darwin Hospital Darwin Northern Territory Australia
| | - Matthew Maddison
- Department of Gastroenterology and Hepatology Royal Darwin Hospital Darwin Northern Territory Australia
| | - Sumudu Narayana
- Hepatology and Liver Transplant Medicine Unit Southern Adelaide Local Health Network Adelaide South Australia Australia
| | - Hien Le
- Department of Radiation Oncology Royal Adelaide Hospital Adelaide South Australia Australia
- The University of South Australia Adelaide South Australia Australia
| | - David Pryor
- Department of Radiation Oncology Princess Alexandra Hospital Brisbane Queensland Australia
- Queensland University of Technology Brisbane Queensland Australia
| | - Alan Wigg
- Hepatology and Liver Transplant Medicine Unit Southern Adelaide Local Health Network Adelaide South Australia Australia
- College of Medicine and Public Health Flinders University Adelaide South Australia Australia
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Narayana S, Nugent M, Woodman R, Larkin M, Ramachandran J, Muller K, Wigg A. Measuring quality of hepatitis B care in a remote Australian Aboriginal community: opportunities for improvement. Intern Med J 2022; 52:1347-1353. [PMID: 33979037 DOI: 10.1111/imj.15349] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 03/02/2021] [Accepted: 05/05/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND Chronic hepatitis B (CHB) infection remains a significant public health issue for Indigenous Australians, in particular for remote communities. AIM To evaluate the spectrum of hepatitis B virus (HBV) care provided to a remote Aboriginal community. Measures studied included screening, seroprevalence, vaccination rates and efficacy, and HCC risk and surveillance adherence. METHODS A retrospective audit of HBV care received by all permanent residents currently attending a remote Aboriginal Health service. This study was endorsed by both the local Aboriginal Health service and the Aboriginal Health Council of South Australia. RESULTS A total of 208 patients attended the clinic, of whom 52% (109) were screened for HBV. Of these, 12% (13) had CHB and 20% (22) had evidence of past infection. Similarly, of the 208 attending patients, complete vaccination was documented in 48% (99). Of the 33 patients with post-vaccination serology, 24% (8) had subtherapeutic (<10 IU/mL) levels of HBsAb. Subtherapeutic HBsAb was independently associated with higher Charlson Comorbidity scores (odds ratio = 17.1; 95% confidence interval 1.2-243.3; P = 0.036). Definitive breakthrough infection was identified in 6% (2) patients. One HBsAg positive patient was identified as needing HCC surveillance, but had not undertaken HCC surveillance. CONCLUSION Opportunities to improve the quality of CHB care through increased HBV vaccination, screening and adherence to HCC surveillance were identified. High rates of subtherapeutic vaccine responses and documented breakthrough infection raises concerns about the effectiveness of current CHB vaccines in this population.
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Affiliation(s)
- Sumudu Narayana
- Hepatology and Liver Transplantation Medicine Unit, Flinders Medical Centre, Adelaide, South Australia, Australia
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Michael Nugent
- Tullawon Health Service, Yalata, South Australia, Australia
| | - Richard Woodman
- Flinders Centre for Epidemiology and Biostatistics, School of Medicine and Public Health, Flinders University of South Australia, Adelaide, South Australia, Australia
| | - Michael Larkin
- Aboriginal Health Council of South Australia, Adelaide, South Australia, Australia
| | - Jeyamani Ramachandran
- Hepatology and Liver Transplantation Medicine Unit, Flinders Medical Centre, Adelaide, South Australia, Australia
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Kate Muller
- Hepatology and Liver Transplantation Medicine Unit, Flinders Medical Centre, Adelaide, South Australia, Australia
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Alan Wigg
- Hepatology and Liver Transplantation Medicine Unit, Flinders Medical Centre, Adelaide, South Australia, Australia
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
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Narayana S, Nugent M, Woodman R, Larkin M, Ramachandran J, Muller K, Wigg A. Author reply. Intern Med J 2022; 52:1458. [PMID: 35973962 DOI: 10.1111/imj.15841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 05/15/2022] [Indexed: 11/26/2022]
Affiliation(s)
- Sumudu Narayana
- Hepatology and Liver Transplantation Medicine Unit, Flinders Medical Centre, Adelaide, South Australia, Australia.,College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Michael Nugent
- Tullawon Health Service, Yalata, South Australia, Australia
| | - Richard Woodman
- Flinders Centre for Epidemiology and Biostatistics, School of Medicine and Public Health, Flinders University of South Australia, Adelaide, South Australia, Australia
| | - Michael Larkin
- Aboriginal Health Council of South Australia, Adelaide, South Australia, Australia
| | - Jeyamani Ramachandran
- Hepatology and Liver Transplantation Medicine Unit, Flinders Medical Centre, Adelaide, South Australia, Australia.,College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Kate Muller
- Hepatology and Liver Transplantation Medicine Unit, Flinders Medical Centre, Adelaide, South Australia, Australia.,College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Alan Wigg
- Hepatology and Liver Transplantation Medicine Unit, Flinders Medical Centre, Adelaide, South Australia, Australia.,College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
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Kumar PR, Ravichandran S, Narayana S. Optimization assisted hybrid intelligent system for heart disease prediction. J MECH MED BIOL 2022. [DOI: 10.1142/s0219519422500518] [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: 11/18/2022]
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Tandon B, Ramachandran J, Narayana S, Muller K, Pathi R, Wigg AJ. Outcomes of transjugular intrahepatic portosystemic shunt procedures: a 10-year experience. J Med Imaging Radiat Oncol 2021; 65:655-662. [PMID: 33687155 DOI: 10.1111/1754-9485.13168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 01/24/2021] [Accepted: 02/15/2021] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Transjugular intrahepatic portosystemic shunt (TIPSS) is an effective modality in reducing portal pressure, and its current main indications are for the management of recurrent ascites and variceal bleeding. The demand and indications for TIPSS are growing. However, it is a complicated and technically demanding procedure with poorer outcomes associated with low volume centres. The aim of this study was, therefore, to review the outcomes of TIPSS at a 'low volume' single centre. Outcomes assessed included indications, safety, efficacy and survival. METHODS A retrospective study was undertaken of all patients who underwent a TIPSS procedure over 10 years at tertiary referral centre for complex liver disease and transplantation. Kaplan-Meier method was used to calculate actuarial survival and log-rank analysis was used to determine significant differences in survival. RESULTS Thirty-eight patients underwent the TIPSS procedure between January 2008 and December 2018. Technical, haemodynamic and clinical success were 95%, 92% and 92% respectively. Cumulative survival at one month, one year and five years were 86.8%, 72% and 44.7% respectively. Results achieved standards published in practice parameters to evaluate TIPSS safety and efficacy. CONCLUSION At a low volume centre, TIPSS usage was associated with high rates of technical, haemodynamic (HPVG reduction) and clinical success. Low volume should not be a contraindication to providing a TIPSS service; however, auditing outcomes and understanding specific institutional factors that influence quality are important requirements for low volume centres.
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Affiliation(s)
- Bhuwan Tandon
- Hepatology and Transplant Medicine Unit, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Jeyamani Ramachandran
- Hepatology and Transplant Medicine Unit, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Sumudu Narayana
- Hepatology and Transplant Medicine Unit, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Kate Muller
- Hepatology and Transplant Medicine Unit, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Ramon Pathi
- Department of Radiology, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Alan J Wigg
- Hepatology and Transplant Medicine Unit, Flinders Medical Centre, Adelaide, South Australia, Australia
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Koh YH, Ong JHY, McCartney E, Morgan J, Narayana S, Tse E. Clinical factors leading to a change in management in chronic hepatitis B patients managed in a tertiary setting. Intern Med J 2021; 50:177-184. [PMID: 31449717 DOI: 10.1111/imj.14622] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 08/08/2019] [Accepted: 08/19/2019] [Indexed: 01/05/2023]
Abstract
BACKGROUND Newer antiviral agents for chronic hepatitis B (CHB) are highly effective, with minimal risks of complications and development of resistance. AIM To identify the proportion of patients with CHB on treatment who will not require alteration of management and the clinical factors of those who will require closer monitoring. METHODS Patients with CHB who were on entecavir and/or tenofovir between January 2011 and December 2016 were retrospectively studied. According to the initial treatment plan provided by the managing physician, any deviation in the interval of follow up, choice of investigations and alteration of medical therapy were considered a change in CHB management. We also evaluated the predictability of these changes, factors associated with higher frequency of change and the additional cost of managing stable patients with CHB in a tertiary setting. RESULTS Of the patients, 75.7% (n = 87/115) did not have a change in CHB management; 85.6% of the changes in management were predictable based on liver function tests, hepatitis B virus DNA polymerase chain reaction levels and liver ultrasound. Interpreter use (OR (95% CI) = 2.41 (1.01-5.76)), liver cirrhosis (OR (95% CI) = 4.11 (1.44-11.75)) and immunosuppression (OR (95% CI) = 3.81 (1.2-12.06)) were associated risk factors. Overall, there was an incremental annual cost of AU$60 166 to manage patients who did not require alteration of their CHB management in our institution. CONCLUSION The majority of stable CHB patients on highly potent antiviral treatment do not require alteration of management. While additional investigations are required, this study highlights the potential for a shared primary care approach in highly selected CHB patients.
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Affiliation(s)
- Yu Han Koh
- School of Medicine, The University of Adelaide, Adelaide, South Australia, Australia
| | - Joanne Hui Yi Ong
- School of Medicine, The University of Adelaide, Adelaide, South Australia, Australia
| | - Erin McCartney
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Joanne Morgan
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Sumudu Narayana
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Edmund Tse
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
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Narayana S, Fulton S, McGregor A, Mudigoudar B, Weatherspoon S, Boop F, Wheless J. P236 Utility of TMS for presurgical motor and language mapping in young children with refractory focal epilepsy and brain tumor. Clin Neurophysiol 2020. [DOI: 10.1016/j.clinph.2019.12.347] [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: 11/24/2022]
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Narayana S, Schiller K, Boop F, Wheless J, Papanicolaou A. P269 Utility of TMS in presurgical mapping of eloquent cortices in children. Clin Neurophysiol 2017. [DOI: 10.1016/j.clinph.2016.10.380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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10
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Helbig KJ, Eyre NS, Yip E, Narayana S, Li K, Fiches G, McCartney EM, Jangra RK, Lemon SM, Beard MR. The antiviral protein viperin inhibits hepatitis C virus replication via interaction with nonstructural protein 5A. Hepatology 2011; 54:1506-17. [PMID: 22045669 PMCID: PMC3207276 DOI: 10.1002/hep.24542] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
UNLABELLED The interferon-stimulated gene, viperin, has been shown to have antiviral activity against hepatitis C virus (HCV) in the context of the HCV replicon, although the molecular mechanisms responsible are not well understood. Here, we demonstrate that viperin plays an integral part in the ability of interferon to limit the replication of cell-culture-derived HCV (JFH-1) that accurately reflects the complete viral life cycle. Using confocal microscopy and fluorescence resonance energy transfer (FRET) analysis, we demonstrate that viperin localizes and interacts with HCV nonstructural protein 5A (NS5A) at the lipid-droplet (LD) interface. In addition, viperin also associates with NS5A and the proviral cellular factor, human vesicle-associated membrane protein-associated protein subtype A (VAP-A), at the HCV replication complex. The ability of viperin to limit HCV replication was dependent on residues within the C-terminus, as well as an N-terminal amphipathic helix. Removal of the amphipathic helix-redirected viperin from the cytosolic face of the endoplasmic reticulum and the LD to a homogenous cytoplasmic distribution, coinciding with a loss of antiviral effect. C-terminal viperin mutants still localized to the LD interface and replication complexes, but did not interact with NS5A proteins, as determined by FRET analysis. CONCLUSION In conclusion, we propose that viperin interacts with NS5A and the host factor, VAP-A, to limit HCV replication at the replication complex. This highlights the complexity of the host control of viral replication by interferon-stimulated gene expression.
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Affiliation(s)
- Karla J. Helbig
- Centre for Cancer Biology, Hanson Centre, Adelaide, South Australia and School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, 5000, Australia
| | - Nicholas S. Eyre
- Centre for Cancer Biology, Hanson Centre, Adelaide, South Australia and School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, 5000, Australia
| | - Evelyn Yip
- Centre for Cancer Biology, Hanson Centre, Adelaide, South Australia and School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, 5000, Australia
| | - Sumudu Narayana
- Centre for Cancer Biology, Hanson Centre, Adelaide, South Australia and School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, 5000, Australia
| | - Kui Li
- Department of Molecular Sciences, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Guillaume Fiches
- Centre for Cancer Biology, Hanson Centre, Adelaide, South Australia and School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, 5000, Australia
| | - Erin M. McCartney
- Centre for Cancer Biology, Hanson Centre, Adelaide, South Australia and School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, 5000, Australia
| | - Rohit K. Jangra
- Center for Hepatitis Research, Institute for Human Infections and Immunity, University of Texas Medical Branch at Galveston, Galveston, TX, 77555, USA,Department of Microbiology & Immunology, Mt. Sinai School of Medicine, New York, NY 10029, USA
| | - Stanley M. Lemon
- Center for Hepatitis Research, Institute for Human Infections and Immunity, University of Texas Medical Branch at Galveston, Galveston, TX, 77555, USA,Inflammatory Diseases Institute, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7295 USA
| | - Michael R. Beard
- Centre for Cancer Biology, Hanson Centre, Adelaide, South Australia and School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, 5000, Australia
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Ranade AV, Rai R, Pai MM, Nayak SR, Krisnamurthy A, Narayana S. Anatomical variations of the thyroid gland: possible surgical implications. Singapore Med J 2008; 49:831-834. [PMID: 18946620] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
INTRODUCTION The organogenesis of the thyroid gland in humans is often disturbed, leading to a variety of morphological variations of the gland, such as hypoplasia, ectopy, hemiagenesis and agenesis. As the morphological variations are usually diagnosed incidentally during examination for other thyroid gland diseases, the true incidence is therefore uncertain. METHODS This study was structured to investigate the gross anatomical features of the thyroid gland in 105 (88 male and 17 female) cadavers from the coastal belt of southern India, an endemic goitre region. RESULTS The pyramidal lobe was present in 61 (58 percent) male cadavers, and 52 (49.5 percent) cadavers showed the presence of the levator glandulae thyroideae. 33 percent of the specimens studied showed agenesis of the isthmus. However, the accessory thyroid tissue was found in only one cadaver. CONCLUSION This study highlights the various developmental anomalies of the thyroid gland, which forms a cornerstone to safe and effective surgery.
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Affiliation(s)
- A V Ranade
- Department of Anatomy, Kasturba Medical College, Mangalore, Karnataka 575004, India.
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Mayne R, Ren ZX, Liu J, Cook T, Carson M, Narayana S. VIT-1: the second member of a new branch of the von Willebrand factor A domain superfamily. Biochem Soc Trans 1999; 27:832-5. [PMID: 10830112 DOI: 10.1042/bst0270832] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- R Mayne
- Department of Cell Biology, University of Alabama at Birmingham 35294, USA
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Narayana S, Hichwa RD, Ponto LL, Hurtig RR, Watkins GL. Construction of a whole body blood flow model for use in positron emission tomography imaging with [15O]water. J Pharmacokinet Biopharm 1997; 25:539-68. [PMID: 9679222 DOI: 10.1023/a:1025759213617] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A whole body blood flow model (WBBFM) was developed and tested using STELLA II, an icon-driven mathematical simulation software package. The WBBFM uses parallel chambers to represent gray and white areas of the brain, body organs such as lungs, heart (right and left halves), injection site, and blood sampling sites. Input values to the WBBFM include organ blood flows, organ volumes, tissue:blood partition coefficients, injected activity, and data acquisition times for a positron emission tomography (PET) camera. Input variables included an injection function (e.g., bolus), and a blood flow function (e.g., transient variations in flow). The kinetic behavior of [15O]water, a freely diffusible radiotracer employed in PET to characterize blood flow was examined by the WBBFM. The physiologic behavior of water in the human body was emulated using the WBBFM and the model's predictive value was verified by comparing calculated results with the following properties of water: diffusibility, tissue:blood partition coefficient of [15O]water, and the mixing of [15O]water with total body water. The WBBFM simulated Kety's autoradiographic method used in the estimation of regional cerebral blood flow by PET using [15O]water. The application of the model to a cognitive activation study paradigm based on Kety's method is presented and its results compared to published literature data. With appropriate modification in the half-life, tissue:blood partition coefficient, and the amount of administered radioactivity, the WBBFM should prove useful as a tool to examine kinetics of other freely diffusible radiotracers used in PET.
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Affiliation(s)
- S Narayana
- P.E.T. Imaging Center, University of Iowa Hospitals and Clinics, Iowa City 52242, USA
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Abstract
Earlier dosimetry estimates for [15O]water assumed its instantaneous equilibrium with total body water. This assumption leads to an underestimation of the absorbed doses to organs with high blood flows, since the biodistribution of this short-lived radiopharmaceutical is dependent upon blood flow to organs. We have developed a physiologically based whole body blood flow model (WBBFM) using a commercially available icon-driven mathematical simulation software package and applied it to the reevaluation of [15O]water dosimetry in humans. The WBBFM uses multiple parallel compartments to represent organs, heart chambers, the injection site for [15O]water, and blood sampling sites (arterial and venous). Input values to the WBBFM include organ blood flows, organ masses, organ water volumes, organ:blood partition coefficients, injected activity and S-values of [15O]. The WBBFM is based on the same assumptions that are used in calculating regional blood flow using [15O]water and simulates the human body closely in its physiologic response. The activity in each organ is derived from the simulation and is used to calculate absorbed doses. The WBBFM calculated absorbed doses in microGy/MBq (mrad/mCi) to various organs are as follows: heart--2.66 (9.84), kidneys--2.20 (8.15), thyroid--1.83 (6.78), brain--1.66 (6.13), ovaries--1.25 (4.61), breast--1.24 (4.59), and small intestine--1.03 (3.83). These values are approximately two- to threefold higher than the earlier estimates of Kearfott [J. Nucl. Med. 23, 1031-1037 (1982)] and similar to the recent findings of Herscovitch et al. [J. Nucl. Med. 34, 155P (1983)]. We believe this approach yields more realistic dosimetry estimates for [15O]water. Accordingly, we have revised the amount of [15O]water administered during regional blood flow studies at our institution. The relative ease and accuracy of this approach suggests its usefulness in dosimetry estimation for other freely diffusible radiopharmaceuticals.
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Affiliation(s)
- S Narayana
- Department of Radiology, University of Iowa, Iowa City 52242, USA
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Hurtig RR, Hichwa RD, O'Leary DS, Boles Ponto LL, Narayana S, Watkins GL, Andreasen NC. Effects of timing and duration of cognitive activation in [15O]water PET studies. J Cereb Blood Flow Metab 1994; 14:423-30. [PMID: 8163584 DOI: 10.1038/jcbfm.1994.53] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The multiple injection [15O]water method offers unique opportunities for studying cognitive processing by the human brain. The influence of the duration and temporal placement of an activation task, in relation to the arrival of the radiotracer in the brain, is a fundamental methodologic question for cognitive activation studies. A quantitative positron emission tomography (PET) study of five normal volunteers was performed in which the stimulation consisted of a visual activation task (alternating checkerboard pattern) superimposed on an auditory baseline task (syllable monitoring). Ten injection conditions, with varying duration and timing of the visual activation, were used. Regional CBF (rCBF) in visual cortex was measured quantitatively using the autoradiographic method. A 20-s stimulation, centered on the bolus arrival in the brain, produced significant changes in rCBF. Because varying the duration and timing of the activation task technically violates the temporal homogeneity assumption of the autoradiographic model, a mathematical simulation was formulated to evaluate the potential influence of these variations. Results of the simulation are consistent with the PET data and suggest that activation can be limited to a narrow temporal window centered on the radiotracer uptake. The ability to observe significant changes in rCBF with short stimulation intervals is of particular interest in the use of [15O]water PET for studies of cognitive processes with a short time course.
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Affiliation(s)
- R R Hurtig
- Department of Speech Pathology and Audiology, University of Iowa, Iowa City
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