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Abstract
The widely distributed, essential redox factor pyrroloquinoline quinone (PQQ, methoxatin) (1) was discovered in the mid-1960s. The breadth and depth of its biological effects are steadily being revealed, and understanding its biosynthesis at the genomic level is a continuing process. In this review, aspects of the chemistry, biology, biosynthesis, and commercial production of 1 at the gene level, and some applications, are presented from discovery through to mid-2021.
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Affiliation(s)
- Geoffrey A Cordell
- Natural Products Inc., Evanston, Illinois 60202, United States.,Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
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2
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Xu NY, Nguyen KT, Mehta C, Klonoff DC. Antioxidant-Induced Pseudohyperglycemia Due to Interference of Measurements by Blood Glucose Monitors. J Diabetes Sci Technol 2021; 15:1404-1405. [PMID: 34474582 PMCID: PMC8655286 DOI: 10.1177/19322968211041328] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Nicole Y. Xu
- Diabetes Technology Society, Burlingame, CA,
USA
| | | | - Chhavi Mehta
- Palo Alto Foundation Medical Group,
Burlingame, CA, USA
| | - David C. Klonoff
- Mills-Peninsula Medical Center, San Mateo,
CA, USA
- David C. Klonoff, MD, FACP, FRCP (Edin), Fellow
AIMBE, Diabetes Research Institute, Mills-Peninsula Medical Center, Room 5147, 100 South
San Mateo Drive, San Mateo, CA 94401, USA.
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3
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Abstract
The aim of this study was to assess the accuracy of blood glucose monitors (BGMs) from studies reported in the medical literature. A literature review was performed of publications between 2010 and 2017 that presented data about the accuracy of BGMs using ISO 15197 2003 and/or ISO 15197 2013 as target standards. We found 58 publications describing the performance of 143 unique BGM systems, 59 of which were Food and Drug Administration (FDA) cleared. When compared with non-FDA-cleared BGMs, FDA-cleared BGMs were significantly more likely to pass both ISO 15197 2003 (OR = 2.39, CI 1.45-3.92, P < 0.01) and ISO 15197 2013 standards (OR = 2.20, CI 1.51-3.27, P < 0.01). Newer meters were more likely to pass both ISO 15197 2003 and ISO 15197 2013 standards. Many of the studies were supported by BGM manufacturers, and when compared with independent studies, an FDA-cleared BGM was significantly more likely to pass in a manufacturer-supported study for both ISO 15197 2003 (OR = 22.4, CI 8.73-21.57, P < 0.001) and ISO 15197 2013 (OR = 23.08, CI 10.16-60.03, P < 0.001). BGM accuracy should be assessed independently following regulatory clearance to ensure accurate performance. Failure to meet performance levels mandated by standards can result in deleterious clinical and economic effects.
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Affiliation(s)
- Fraya King
- 1 Diabetes Research Institute, Mills-Peninsula Medical Center , San Mateo, California
| | - David Ahn
- 2 Department of Endocrinology, University of California , Los Angeles, Valencia, California
| | - Victoria Hsiao
- 3 Department of Medicine, University of California, San Francisco , San Francisco, California
| | - Travis Porco
- 4 FI Proctor Foundation for Research in Ophthalmology and Department of Ophthalmology, University of California , San Francisco, San Francisco, California
| | - David C Klonoff
- 1 Diabetes Research Institute, Mills-Peninsula Medical Center , San Mateo, California
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Traceability to a primary reference measurement procedure (ID-LCMS); A key step in validating the clinical accuracy and safety of hospital blood glucose monitoring systems. Clin Chim Acta 2018; 486:275-281. [PMID: 30125535 DOI: 10.1016/j.cca.2018.08.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 08/11/2018] [Accepted: 08/14/2018] [Indexed: 11/22/2022]
Abstract
OBJECTIVE A key step in the evaluation of the accuracy of blood glucose monitoring systems (BGMS) is using a comparator method aligned to a high order definitive reference method. We describe how we achieved traceability to an isotope dilution liquid chromatography mass spectrometry (ID-LCMS) method. We used ID-LCMS to evaluate the accuracy and specificity of two hospital BGMS used in China. METHOD ID-LCMS was used to verify the calibration alignment of the laboratory plasma hexokinase reference method using NIST standard reference material and clinical samples. The ID-LCMS aligned hexokinase method was used to evaluate the clinical accuracy of two BGMS in hospitalized patients. System accuracy was evaluated using Chinese consensus guidelines. BGMS accuracy was also assessed with interference factors known to be present in critically ill patients' blood. RESULTS The laboratory plasma hexokinase reference method was shown to calibrate closely with ID-LCMS. Two BGMS demonstrated good correlation with this reference method. Only one BGMS met the Chinese guidelines. The interference factors didn't influence this BGMS but adversely affected the clinical accuracy of the other. CONCLUSIONS We advocate that our IDMS calibration alignment approach for ensuring the accuracy of the glucose reference method should be adopted in evaluations assessing the accuracy of blood glucose monitoring systems.
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Macdonald C, Lunt H, Downie M, Kendall D. How Satisfied Are Patients When Their Choice of Funded Glucose Meter Is Restricted to a Single Brand? J Diabetes Sci Technol 2017; 11:1001-1006. [PMID: 28617624 PMCID: PMC5950980 DOI: 10.1177/1932296817693016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Many governments and insurers are driving down the cost of medical devices, including glucose meters, by the central management of purchasing decisions. We report patients' responses to an "enforced" change in brand of glucose meter, one year after the introduction of a national sole supplier arrangement for funded glucose meters and strips. METHOD Specialist diabetes clinic attendees from two geographical locations completed a questionnaire one year after the final meter changeover date. In the first location, consecutive patients were asked to complete a glucose meter satisfaction questionnaire during their clinic visit. In the second location, this questionnaire was mailed to clinic attendees. Responses to open questions were analyzed thematically. RESULTS Response rates were 85% and 31% from the first and second locations, respectively and 378 questionnaires were suitable for analysis, 309 from the first and 69 from the second location. Insulin users composed 90% of participants. Results from the two locations were broadly similar. Most participants adapted well to the changeover, however 36% reported ongoing dissatisfaction with their "new" meter. The commonest concern, expressed by 23% of participants, related to meter accuracy and precision. CONCLUSIONS One year after glucose meter changeover, a third of participants expressed dissatisfaction with their meter, with many participants describing a failure to adapt to the sole supplier arrangement. Providing a choice of meters and strips, ideally from two or more brands that have demonstrable differences in technical and ergonomic features, is likely to produce higher overall patient satisfaction than is a sole supplier arrangement.
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Affiliation(s)
- Christy Macdonald
- Department of General Medicine, Christchurch Hospital, Christchurch, New Zealand
| | - Helen Lunt
- Department of Medicine, University of Otago Christchurch, Christchurch, New Zealand
- Diabetes Centre, Christchurch Hospital, Christchurch, New Zealand
- Helen Lunt, MD, Department of Medicine, University of Otago Christchurch, Christchurch, New Zealand.
| | - Michelle Downie
- Department of Endocrinology, Southland Hospital, Invercargill, New Zealand
| | - Deborah Kendall
- Diabetes Centre, Christchurch Hospital, Christchurch, New Zealand
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Ekhlaspour L, Mondesir D, Lautsch N, Balliro C, Hillard M, Magyar K, Radocchia LG, Esmaeili A, Sinha M, Russell SJ. Comparative Accuracy of 17 Point-of-Care Glucose Meters. J Diabetes Sci Technol 2017; 11:558-566. [PMID: 27697848 PMCID: PMC5505415 DOI: 10.1177/1932296816672237] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND The accuracy of point-of-care blood glucose (BG) meters is important for the detection of dysglycemia, calculation of insulin doses, and the calibration of continuous glucose monitors. The objective of this study was to compare the accuracy of commercially available glucose meters in a challenging laboratory study using samples with a wide range of reference BG and hemoglobin values. METHODS Fresh, discarded blood samples from a hospital STAT laboratory were either used without modification, spiked with a glucose solution, or incubated at 37°C to produce 347 samples with an even distribution across reference BG levels from 20 to 440 mg/dl and hemoglobin values from 9 to 16 g/dl. We measured the BG of each sample with 17 different commercially available glucose meters and the reference method (YSI 2300) at the same time. We determined the mean absolute relative difference (MARD) for each glucose meter, overall and stratified by reference BG and by hemoglobin level. RESULTS The accuracy of different meters widely, exhibiting a range of MARDs from 5.6% to 20.8%. Accuracy was lower in the hypoglycemic range, but was not consistently lower in samples with anemic blood hemoglobin levels. CONCLUSIONS The accuracy of commercially available glucose meters varies widely. Although the sample mix in this study was much more challenging than those that would be collected under most use conditions, some meters were robust to these challenges and exhibited high accuracy in this setting. These data on relative accuracy and robustness to challenging samples may be useful in informing the choice of a glucose meter.
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Affiliation(s)
- Laya Ekhlaspour
- Massachusetts General Hospital Diabetes Research Center, Boston, MA, USA
| | - Debbie Mondesir
- Massachusetts General Hospital Diabetes Research Center, Boston, MA, USA
| | - Norman Lautsch
- Massachusetts General Hospital Diabetes Research Center, Boston, MA, USA
| | - Courtney Balliro
- Massachusetts General Hospital Diabetes Research Center, Boston, MA, USA
| | - Mallory Hillard
- Massachusetts General Hospital Diabetes Research Center, Boston, MA, USA
| | - Kendra Magyar
- Massachusetts General Hospital Diabetes Research Center, Boston, MA, USA
| | | | - Aryan Esmaeili
- Massachusetts General Hospital Diabetes Research Center, Boston, MA, USA
| | - Manasi Sinha
- Massachusetts General Hospital Diabetes Research Center, Boston, MA, USA
| | - Steven J. Russell
- Massachusetts General Hospital Diabetes Research Center, Boston, MA, USA
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Bimolecular Rate Constants for FAD-Dependent Glucose Dehydrogenase from Aspergillus terreus and Organic Electron Acceptors. Int J Mol Sci 2017; 18:ijms18030604. [PMID: 28287419 PMCID: PMC5372620 DOI: 10.3390/ijms18030604] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 03/07/2017] [Accepted: 03/08/2017] [Indexed: 02/07/2023] Open
Abstract
The flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH) from Aspergillus species require suitable redox mediators to transfer electrons from the enzyme to the electrode surface for the application of bioelectrical devices. Although several mediators for FAD-GDH are already in use, they are still far from optimum in view of potential, kinetics, sustainability, and cost-effectiveness. Herein, we investigated the efficiency of various phenothiazines and quinones in the electrochemical oxidation of FAD-GDH from Aspergillus terreus. At pH 7.0, the logarithm of the bimolecular oxidation rate constants appeared to depend on the redox potentials of all the mediators tested. Notably, the rate constant of each molecule for FAD-GDH was approximately 2.5 orders of magnitude higher than that for glucose oxidase from Aspergillus sp. The results suggest that the electron transfer kinetics is mainly determined by the formal potential of the mediator, the driving force of electron transfer, and the electron transfer distance between the redox active site of the mediator and the FAD, affected by the steric or chemical interactions. Higher k2 values were found for ortho-quinones than for para-quinones in the reactions with FAD-GDH and glucose oxidase, which was likely due to less steric hindrance in the active site in the case of the ortho-quinones.
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Sode K, Loew N, Ohnishi Y, Tsuruta H, Mori K, Kojima K, Tsugawa W, LaBelle JT, Klonoff DC. Novel fungal FAD glucose dehydrogenase derived from Aspergillus niger for glucose enzyme sensor strips. Biosens Bioelectron 2016; 87:305-311. [PMID: 27573296 DOI: 10.1016/j.bios.2016.08.053] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 08/05/2016] [Accepted: 08/17/2016] [Indexed: 02/07/2023]
Abstract
In this study, a novel fungus FAD dependent glucose dehydrogenase, derived from Aspergillus niger (AnGDH), was characterized. This enzyme's potential for the use as the enzyme for blood glucose monitor enzyme sensor strips was evaluated, especially by investigating the effect of the presence of xylose during glucose measurements. The substrate specificity of AnGDH towards glucose was investigated, and only xylose was found as a competing substrate. The specific catalytic efficiency for xylose compared to glucose was 1.8%. The specific activity of AnGDH for xylose at 5mM concentration compared to glucose was 3.5%. No other sugars were used as substrate by this enzyme. The superior substrate specificity of AnGDH was also demonstrated in the performance of enzyme sensor strips. The impact of spiking xylose in a sample with physiological glucose concentrations on the sensor signals was investigated, and it was found that enzyme sensor strips using AnGDH were not affected at all by 5mM (75mg/dL) xylose. This is the first report of an enzyme sensor strip using a fungus derived FADGDH, which did not show any positive bias at a therapeutic level xylose concentration on the signal for a glucose sample. This clearly indicates the superiority of AnGDH over other conventionally used fungi derived FADGDHs in the application for SMBG sensor strips. The negligible activity of AnGDH towards xylose was also explained on the basis of a 3D structural model, which was compared to the 3D structures of A. flavus derived FADGDH and of two glucose oxidases.
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Affiliation(s)
- Koji Sode
- Department of Biotechnology, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan; Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, 3-8-1 Harumi-cho, Fuchu, Tokyo 183-8538, Japan; Ultizyme International Ltd., 1-13-16, Minami, Meguro, Tokyo 152-0013, Japan.
| | - Noya Loew
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, 3-8-1 Harumi-cho, Fuchu, Tokyo 183-8538, Japan
| | - Yosuke Ohnishi
- Department of Biotechnology, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Hayato Tsuruta
- Department of Biotechnology, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Kazushige Mori
- Ultizyme International Ltd., 1-13-16, Minami, Meguro, Tokyo 152-0013, Japan
| | - Katsuhiro Kojima
- Ultizyme International Ltd., 1-13-16, Minami, Meguro, Tokyo 152-0013, Japan
| | - Wakako Tsugawa
- Department of Biotechnology, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan; Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, 3-8-1 Harumi-cho, Fuchu, Tokyo 183-8538, Japan
| | - Jeffrey T LaBelle
- School of Biological and Health System Engineering, Ira A. Fulton Schools of Engineering, Arizona State University, P.O. Box 879709, Tempe, AZ 85287-9709, USA
| | - David C Klonoff
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, 3-8-1 Harumi-cho, Fuchu, Tokyo 183-8538, Japan; Diabetes Research Institute, Mills-Peninsula Health Services, 100 South San Mateo Drive, San Mateo, CA 94401, USA
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Dogan K, Kayalp D, Ceylan G, Azak A, Senes M, Duranay M, Yucel D. Falsely Elevated Glucose Concentrations in Peritoneal Dialysis Patients Using Icodextrin. J Clin Lab Anal 2015; 30:506-9. [PMID: 26511081 DOI: 10.1002/jcla.21887] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 07/27/2015] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Peritoneal dialysis (PD) is used as an alternative to hemodialysis in end-stage renal disease (ESRD). Icodextrin has been used as a hyperosmotic agent in PD. The aim of the study was to assess two different point-of-care testing (POCT) glucose strips, affected and not affected by icodextrin, with serum glucose concentrations of the patients using and not using icodextrin. METHODS Fifty-two chronic ambulatory peritoneal dialysis (CAPD) patients using icodextrin (Extraneal®) and 20 CAPD patients using another hyperosmotic fluid (Dianeal®) were included in the study. Duplicate capillary and serum glucose concentrations were measured with two different POCT glucose strips and central laboratory hexokinase method. Assay principles of glucose strips were based on glucose dehydrogenase-pyrroloquinoline quinone (GDH-PQQ) and a mutant variant of GDH (Mut Q-GDH). The results of both strips were compared with those of hexokinase method. RESULTS Regression equations between POCT and hexokinase methods in icodextrin group were y = 2.55x + 1.12 mmol/l and y = 1.057x + 0.16 mmol/l for the GDH-PQQ and Mut Q-GDH methods, respectively. The mean difference between the results of hexokinase and those of GDH-PQQ and Mut Q-GDH in icodextrin group was 3.41 ± 1.56 and 0.72 ± 0.64 mmol/l, respectively. However, the mean differences were found much lower in the control group; 0.64 mmol/l for GDH-PQQ and 0.52 mmol/l for Mut Q-GDH. CONCLUSION Compared to GDH-PQQ, glucose strips of Mut Q-GDH correlated better with hexokinase method in PD patients using icodextrin.
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Affiliation(s)
- Kübra Dogan
- Department of Clinical Biochemistry, Ankara Training and Research Hospital, Ministry of Health, Ankara, Turkey
| | - Damla Kayalp
- Department of Clinical Biochemistry, Ankara Training and Research Hospital, Ministry of Health, Ankara, Turkey
| | - Gözde Ceylan
- Department of Clinical Biochemistry, Ankara Training and Research Hospital, Ministry of Health, Ankara, Turkey
| | - Alper Azak
- Department of Nephrology, Ankara Training and Research Hospital, Ministry of Health, Ankara, Turkey
| | - Mehmet Senes
- Department of Clinical Biochemistry, Ankara Training and Research Hospital, Ministry of Health, Ankara, Turkey
| | - Murat Duranay
- Department of Nephrology, Ankara Training and Research Hospital, Ministry of Health, Ankara, Turkey
| | - Dogan Yucel
- Department of Clinical Biochemistry, Ankara Training and Research Hospital, Ministry of Health, Ankara, Turkey.
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Bailey T, Wallace JF, Greene C, Pardo S, Brown D, Pflug B, Klaff LJ. Accuracy and user performance evaluation of the Contour® Next Link 2.4 blood glucose monitoring system. Clin Chim Acta 2015; 448:139-45. [DOI: 10.1016/j.cca.2015.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 05/29/2015] [Accepted: 06/01/2015] [Indexed: 10/23/2022]
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Abstract
Cleared blood glucose monitor (BGM) systems do not always perform as accurately for users as they did to become cleared. We performed a literature review of recent publications between 2010 and 2014 that present data about the frequency of inaccurate performance using ISO 15197 2003 and ISO 15197 2013 as target standards. We performed an additional literature review of publications that present data about the clinical and economic risks of inaccurate BGMs for making treatment decisions or calibrating continuous glucose monitors (CGMs). We found 11 publications describing performance of 98 unique BGM systems. 53 of these 98 (54%) systems met ISO 15197 2003 and 31 of the 98 (32%) tested systems met ISO 15197 2013 analytical accuracy standards in all studies in which they were evaluated. Of the tested systems, 33 were identified by us as FDA-cleared. Among these FDA-cleared BGM systems, 24 out of 32 (75%) met ISO 15197 2003 and 15 out of 31 (48.3%) met ISO 15197 2013 in all studies in which they were evaluated. Among the non-FDA-cleared BGM systems, 29 of 65 (45%) met ISO 15197 2003 and 15 out of 65 (23%) met ISO 15197 2013 in all studies in which they were evaluated. It is more likely that an FDA-cleared BGM system, compared to a non-FDA-cleared BGM system, will perform according to ISO 15197 2003 (χ(2) = 6.2, df = 3, P = 0.04) and ISO 15197 2013 (χ(2) = 11.4, df = 3, P = 0.003). We identified 7 articles about clinical risks and 3 articles about economic risks of inaccurate BGMs. We conclude that a significant proportion of cleared BGMs do not perform at the level for which they were cleared or according to international standards of accuracy. Such poor performance leads to adverse clinical and economic consequences.
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Affiliation(s)
- David C Klonoff
- Diabetes Research Institute, Mills-Peninsula Health Services, San Mateo, CA, USA
| | - Priya Prahalad
- Division of Pediatric Endocrinology, University of California, San Francisco, San Francisco, CA, USA
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