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Schneider AL, Racette SD, Kang AK, Reddy AT, Huang JH, Lehmann DS, Price CP, Eide JG, Rodeghiero SR, Conley DB, Welch KC, Kern RC, Shintani‐Smith S, Peters AT, Kato A, Stevens WS, Schleimer RP, Tan BK. Use of intraoperative frontal sinus mometasone-eluting stents decreased interleukin 5 and interleukin 13 in patients with chronic rhinosinusitis with nasal polyps. Int Forum Allergy Rhinol 2022; 12:1330-1339. [PMID: 35362251 PMCID: PMC9525456 DOI: 10.1002/alr.23005] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 03/13/2022] [Accepted: 03/23/2022] [Indexed: 12/30/2022]
Abstract
BACKGROUND Mometasone-eluting stents (MES) have demonstrated improvement in short-term endoscopic outcomes and reduce short- to medium-term rescue interventions. Their effect on the local inflammatory environment, longer-term patient-reported outcomes, and radiographic severity have not been studied. METHODS Middle meatal mucus and validated measures of disease severity were collected before and 6 to 12 months after endoscopic surgery in 52 patients with chronic rhinosinusitis with nasal polyps (CRSwNPs). Operative findings, type 2 mediator concentrations, intraoperative variables, and disease severity measures were compared between those who did and those who did not receive intraoperative frontal MES. RESULTS A total of 52 patients with CRSwNPs were studied; 33 received frontal MES and were compared with 19 who did not. Pre-endoscopic sinus surgery (ESS) middle meatus (MM) interleukin (IL) 13 and eosinophil cationic protein (ECP) were higher in the stented group (p < 0.05), but pre-ESS clinical measures of disease severity were similar as were surgical extent and post-ESS medical management. Intraoperative eosinophilic mucin was more frequent in the stented group (58% vs 11%, p = 0.001). IL-5 (p < 0.05) and IL-13 (p < 0.001) decreased post-ESS in the stented group, but this was not observed in the nonstented group. Post-ESS IL-4 and IL-13 were higher in the nonstented vs stented group (p < 0.05 for both). CONCLUSION Although patients who received intraoperative frontal MES had significantly higher pre-ESS MM IL-13 and ECP, patients who received frontal MES had lower concentrations of IL-4 and IL-13 than those who did not at a median of 8 months post-ESS. However, these changes did not correspond to significantly different measures of symptomatic or radiographic disease severity.
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Affiliation(s)
- Alexander L. Schneider
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Samuel D. Racette
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Anthony K. Kang
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Abhita T. Reddy
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Julia H. Huang
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - David S. Lehmann
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Caroline P.E. Price
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Jacob G. Eide
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Samuel R. Rodeghiero
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - David B. Conley
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Kevin C. Welch
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Robert C. Kern
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Stephanie Shintani‐Smith
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Anju T. Peters
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
- Division of Allergy and ImmunologyDepartment of MedicineNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Atsushi Kato
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
- Division of Allergy and ImmunologyDepartment of MedicineNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Whitney S. Stevens
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
- Division of Allergy and ImmunologyDepartment of MedicineNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Robert P. Schleimer
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
- Division of Allergy and ImmunologyDepartment of MedicineNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Bruce K. Tan
- Department of OtolaryngologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
- Division of Allergy and ImmunologyDepartment of MedicineNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
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Racette SD, Schneider AL, Ganesh M, Huang JH, Lehmann DS, Price CP, Rodegherio SG, Reddy AT, Eide JG, Conley DB, Welch KC, Kern RC, Shintani‐Smith S, Kato A, Schleimer RP, Tan BK. CRS-PRO and SNOT-22 correlations with type 2 inflammatory mediators in chronic rhinosinusitis. Int Forum Allergy Rhinol 2022; 12:1377-1386. [PMID: 35363947 PMCID: PMC9525449 DOI: 10.1002/alr.23002] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 03/08/2022] [Accepted: 03/22/2022] [Indexed: 12/30/2022]
Abstract
The 22-item Sino-Nasal Outcome Test (SNOT-22) and 12-item Patient Reported Outcomes in Chronic Rhinosinusitis (CRS-PRO) instrument are validated patient-reported outcomes measures in CRS. In this study we assess the correlation of these with type 2 (T2) biomarkers before and after endoscopic sinus surgery (ESS). METHODS Middle meatal mucus data were collected and the SNOT-22 and CRS-PRO were administered to 123 patients (71 CRS without nasal polyps [CRSsNP], 52 CRS with nasal polyps [CRSwNP]) with CRS before and 6 to 12 months after undergoing ESS. Interleukin (IL)-4, IL-5, IL-13, and eosinophilic cationic protein (ECP) were measured using a multiplexed bead assay and enzyme-linked immunoassay. Pre- and post-ESS SNOT-22 and CRS-PRO were compared with T2 biomarkers. RESULTS Before ESS neither PROM correlated with any biomarker. After ESS, CRS-PRO showed a correlation with 2 mediators (IL-5 and IL-13: p = 0.012 and 0.003, respectively) compared with none for the SNOT-22. For CRSwNP patients, pre-ESS CRS-PRO and SNOT-22 correlated with IL-4 (p = 0.04 for both). However, after ESS, CRS-PRO correlated with 3 biomarkers (IL-5, IL-13, and ECP: p = 0.02, 0.024, and 0.04, respectively) and SNOT-22 with 2 biomarkers (IL-5 and IL-13: p = 0.038 and 0.02, respectively). There were no significant relationships between any of the T2 biomarkers pre- or post-ESS among patients with CRSsNP. Exploratory analyses of the subdomains showed the SNOT-22 rhinologic and CRS-PRO rhinopsychologic subdomains correlated better with the T2 biomarkers. On individual item analysis, IL-13 correlated significantly post-ESS with 8 of 12 items on the CRS-PRO vs 6 of 22 items on the SNOT-22. CONCLUSION The CRS-PRO total score showed a significant correlation with T2 biomarkers especially when assessed post-ESS and among CRSwNP patients.
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Affiliation(s)
- Samuel D. Racette
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
| | - Alexander L. Schneider
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
| | - Meera Ganesh
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
| | - Julia H. Huang
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
| | - David S. Lehmann
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
| | - Caroline P.E. Price
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
| | - Samuel G. Rodegherio
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
| | - Abhita T. Reddy
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
| | - Jacob G. Eide
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
| | - David B. Conley
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
| | - Kevin C. Welch
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
| | - Robert C. Kern
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
| | - Stephanie Shintani‐Smith
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
| | - Atsushi Kato
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
- Division of Allergy and ImmunologyDepartment of MedicineNorthwestern University Feinberg School of MedicineChicagoIL
| | - Robert P. Schleimer
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
- Division of Allergy and ImmunologyDepartment of MedicineNorthwestern University Feinberg School of MedicineChicagoIL
| | - Bruce K. Tan
- Department of Otolaryngology‐Head and Neck SurgeryNorthwestern University Feinberg School of MedicineChicagoIL
- Division of Allergy and ImmunologyDepartment of MedicineNorthwestern University Feinberg School of MedicineChicagoIL
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Patel GB, Kudlaty EA, Guo A, Yeh C, Kim MS, Price CP, Conley D, Grammer LC, Kalhan R, Kern RC, McGrath KG, Tan BK, Rosenberg SR, Schleimer RP, Smith SS, Stevens WW, Welch KC, Peters AT. Impact of type 2 targeting biologics on acute exacerbations of chronic rhinosinusitis. Allergy Asthma Proc 2021; 42:417-424. [PMID: 34474711 DOI: 10.2500/aap.2021.42.210058] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Background: Acute exacerbations of chronic rhinosinusitis (AECRS) are associated with significant morbidity and decreased quality of life. There are sparse data assessing the real-world impact of biologics on AECRS. Objectives: We sought to determine the impact of type 2-targeting biologics on the frequency of medication use for AECRS episodes. Methods: Antibiotic and/or systemic corticosteroid courses for AECRS were identified in a retrospective study from November 2015 to February 2020, at a single academic health system. The estimated yearly rates for antibiotic and corticosteroid courses were evaluated before and after initiation of type 2 biologics. Results: One-hundred and sixty-five patients with chronic rhinosinusitis (CRS) had received either omalizumab (n = 12), mepolizumab (n = 42), benralizumab (n = 44), dupilumab (n = 61), or reslizumab (n = 6). Seventy percent had CRS with nasal polyps, and 30% had CRS without nasal polyps. All the patients had asthma. When all the biologics were combined, the estimated yearly rate for antibiotics for AECRS decreased from 1.34 (95% confidence interval [CI], 1.12-1.59) to 0.68 (95% CI, 0.52-0.88) with biologic use (49% reduction, p < 0.001). Those with frequent AECRS (three or more courses of antibiotics in the 1 year before biologic use) had a larger degree of reduction, with an estimated yearly rate of 4.15 (95% CI, 3.79-4.55) to 1.58 (95% CI, 1.06-2.35) with biologic use (n = 27; 62% reduction; p < 0.001). Within the total cohort, the estimated yearly rate for systemic corticosteroids for AECRS decreased from 1.69 (95% CI, 1.42-2.02) to 0.68 (95% CI, 0.53-0.88) with biologic use (60% reduction; p < 0.001). Conclusion: Type 2-targeting biologics reduced medication use for AECRS. This suggested that biologics may be a therapeutic option for patients with frequent AECRS.
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Affiliation(s)
- Gayatri B. Patel
- From the Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Elizabeth A. Kudlaty
- From the Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Amina Guo
- From the Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Chen Yeh
- Division of Biostatistics, Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Margaret S. Kim
- From the Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Caroline P.E. Price
- Department of Otolaryngology-Head and Neck Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - David Conley
- Department of Otolaryngology-Head and Neck Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Leslie C. Grammer
- From the Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Ravi Kalhan
- Division of Pulmonary and Critical Care, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, and
| | - Robert C. Kern
- From the Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Kris G. McGrath
- From the Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Bruce K. Tan
- From the Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Sharon R. Rosenberg
- Division of Pulmonary and Critical Care, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, and
| | - Robert P. Schleimer
- From the Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Stephanie S. Smith
- Department of Otolaryngology-Head and Neck Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Whitney W. Stevens
- From the Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Kevin C. Welch
- Department of Otolaryngology-Head and Neck Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Anju T. Peters
- From the Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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4
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Takahashi T, Kato A, Suh LA, Carter RG, Stevens WW, Price CP, Norton JE, Weibman AR, Harris KE, Peters AT, Grammer LC, Welch K, Shintani‐Smith S, Conley DB, Berdnikovs S, Tan BK, Kern RC, Schleimer RP. Integrin β6 microparticles in nasal lavage fluids; potential new biomarkers for basal cell activation in chronic rhinosinusitis. Allergy 2020; 75:3261-3264. [PMID: 32455472 PMCID: PMC7688485 DOI: 10.1111/all.14419] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/07/2020] [Accepted: 05/13/2020] [Indexed: 01/10/2023]
Affiliation(s)
- Toru Takahashi
- Division of Allergy‐Immunology Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Atsushi Kato
- Division of Allergy‐Immunology Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
- Department of Otolaryngology Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Lydia A. Suh
- Division of Allergy‐Immunology Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Roderick G. Carter
- Division of Allergy‐Immunology Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Whitney W. Stevens
- Division of Allergy‐Immunology Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Caroline P.E. Price
- Department of Otolaryngology Northwestern University Feinberg School of Medicine Chicago IL USA
| | - James E. Norton
- Division of Allergy‐Immunology Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Ava R. Weibman
- Department of Otolaryngology Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Kathleen E. Harris
- Division of Allergy‐Immunology Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Anju T. Peters
- Division of Allergy‐Immunology Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Leslie C. Grammer
- Division of Allergy‐Immunology Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Kevin Welch
- Department of Otolaryngology Northwestern University Feinberg School of Medicine Chicago IL USA
| | | | - David B. Conley
- Department of Otolaryngology Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Sergejs Berdnikovs
- Division of Allergy‐Immunology Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Bruce K. Tan
- Division of Allergy‐Immunology Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
- Department of Otolaryngology Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Robert C. Kern
- Division of Allergy‐Immunology Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
- Department of Otolaryngology Northwestern University Feinberg School of Medicine Chicago IL USA
| | - Robert P. Schleimer
- Division of Allergy‐Immunology Department of Medicine Northwestern University Feinberg School of Medicine Chicago IL USA
- Department of Otolaryngology Northwestern University Feinberg School of Medicine Chicago IL USA
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5
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Min JY, Huang JH, Norton JE, Suh LA, Price CP, Carter RG, Jung SY, Kim HS, Conley DB, Shintani-Smith S, Welch KC, Peters AT, Grammer LC, Stevens WW, Hulse KE, Kato A, Kern RC, Schleimer RP, Tan BK. IL-13 acidifies airway surface liquid pH via an omeprazole inhibitable mechanism. J Allergy Clin Immunol 2018. [DOI: 10.1016/j.jaci.2017.12.392] [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: 10/18/2022]
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6
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Stevens WW, Hulse KE, Poposki JA, Suh LA, Norton J, Carter RG, Kato A, Grammer LC, Harris KE, Peters AT, Price CP, Conley DB, Kern RC, Smith SS, Tan BK, Welch KC, Schleimer RP. Basophil Activation in Aspirin Exacerbated Respiratory Disease. J Allergy Clin Immunol 2017. [DOI: 10.1016/j.jaci.2016.12.248] [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: 10/20/2022]
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7
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Min JY, Kern RC, Ocampo CJ, Stevens WW, Price CP, Thompson CF, Homma T, Conley DB, Shintani-Smith S, Huang JH, Suh L, Norton JE, Hulse KE, Kato A, Schleimer RP, Tan BK. Proton Pump Inhibitors (PPIs) May Modulate More Than Just Reflux in Chronic Rhinosinusitis with Nasal Polyps. J Allergy Clin Immunol 2016. [DOI: 10.1016/j.jaci.2015.12.1179] [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: 11/16/2022]
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8
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Harding-Esch E, Sherrard-Smith E, Dangerfield C, Choi YH, Green N, Jit M, Marshall RD, Mercer C, Nardone A, Howell-Jones R, Johnson OA, Clarkson J, Wolstenholme J, Price CP, Gaydos CA, Sadiq ST, White PJ, Lowndes CM. P08.29 Web-tool to assess the cost-effectiveness of chlamydia point-of-care tests at the local level. Br J Vener Dis 2015. [DOI: 10.1136/sextrans-2015-052270.375] [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: 11/03/2022]
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9
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Newman DJ, Medcalf E, Gorman EG, Price CP. Latex-enhanced immunoturbidimetric assays of specific proteins in the monitoring of renal function. Contrib Nephrol 2015; 83:19-22. [PMID: 2100711 DOI: 10.1159/000418770] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- D J Newman
- Department of Clinical Biochemistry, London Hospital Medical College, UK
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10
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Kennon S, Price CP, Mills PG, Macey M, Cooper J, Clarke H, Timmis AD. The central role of platelet activation in determining the severity of acute coronary syndromes. Heart 2003; 89:1253-4. [PMID: 12975438 PMCID: PMC1767871 DOI: 10.1136/heart.89.10.1253] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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11
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Kennon S, Price CP, Mills PG, MacCallum PK, Cooper J, Hooper J, Clarke H, Timmis AD. Cumulative risk assessment in unstable angina: clinical, electrocardiographic, autonomic, and biochemical markers. Heart 2003; 89:36-41. [PMID: 12482787 PMCID: PMC1767509 DOI: 10.1136/heart.89.1.36] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES To determine the incremental value of clinical data, troponin T, ST segment monitoring, and heart rate variability for predicting outcome in patients with non-ST elevation acute coronary syndromes. METHODS Prospective cohort study of 304 consecutive patients. Baseline clinical and electrocardiographic data were recorded, serial blood samples were obtained for troponin T assay, and 48 hour Holter monitoring was performed for ST segment and heart rate variability analysis. End points were cardiac death and non-fatal myocardial infarction during 12 months' follow up. RESULTS After 12 months, 7 patients had died and 21 had had non-fatal myocardial infarction. The risk of an event was increased by troponin T > 0.1 microg/l, T wave inversion on the presenting ECG, Holter ST shift, and a decrease in the standard deviation of 5 minute mean RR intervals. Positive predictive values of individual multivariate risk were low; however, analysis of all multivariate risk markers permitted calculation of a cumulative risk score, which increased the positive predictive value to 46.9% while retaining a negative predictive value of 96.9%. CONCLUSION A cumulative approach to risk stratification in non-ST elevation coronary syndromes successfully identifies a group in whom the risk of cardiac death or non-fatal myocardial infarction approaches 50%.
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MESH Headings
- Angina, Unstable/blood
- Angina, Unstable/etiology
- Angina, Unstable/physiopathology
- Arrhythmias, Cardiac/blood
- Arrhythmias, Cardiac/complications
- Arrhythmias, Cardiac/physiopathology
- Creatine Kinase/blood
- Creatine Kinase, MB Form
- Death, Sudden, Cardiac/etiology
- Electrocardiography, Ambulatory
- Epidemiologic Methods
- Female
- Humans
- Isoenzymes/blood
- Male
- Middle Aged
- Myocardial Infarction/blood
- Myocardial Infarction/etiology
- Myocardial Infarction/physiopathology
- Risk Assessment
- Troponin T/blood
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Affiliation(s)
- S Kennon
- Department of Cardiology, Barts and the London NHS Trust, London, UK.
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12
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Timms PM, Mannan N, Hitman GA, Noonan K, Mills PG, Syndercombe-Court D, Aganna E, Price CP, Boucher BJ. Circulating MMP9, vitamin D and variation in the TIMP-1 response with VDR genotype: mechanisms for inflammatory damage in chronic disorders? QJM 2002; 95:787-96. [PMID: 12454321 DOI: 10.1093/qjmed/95.12.787] [Citation(s) in RCA: 331] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Vitamin-D deficiency and vitamin-D receptor genotype (VDR) are risk factors for several disorders with inflammatory components, including coronary heart disease (CHD) and diabetes, though the mechanisms involved are unclear. AIM To examine the hypothesis that vitamin D status modulates the matrix metalloproteinase (MMP) system in a population with a high prevalence of vitamin D deficiency, a situation affecting susceptibility to CHD and diabetes. DESIGN Prospective cross-sectional, interventional and embedded studies. METHODS Circulating MMP2,9, the inhibitor TIMP-1 and C-reactive protein (CRP) were measured during studies of vitamin-D deficiency as a risk factor for type 2 diabetes and CHD in 171 healthy British Bangladeshi adults, free of known diabetes or major illness. Vitamin D status, VDR genotype, body-build, blood pressure, lipid and insulin profiles, glucose tolerance, fibrinogen, PAI-1, folate and homocysteine were measured. Vitamin-D-deficient subjects were re-assessed after 1 years' supplementation. MMP, TIMP-1 and CRP levels were measured in 41 subjects halfway through 5-year follow-up. Independent determinants of circulating concentrations of MMP9, TIMP-1 and CRP were assessed by multiple regression analysis. RESULTS Vitamin D status was the sole determinant of circulating MMP9 (inversely) and an independent determinant of CRP (inversely). Determinants of TIMP-1 were MMP9, systolic blood-pressure (directly) and VDR genotype (TaqI). Significant reductions in MMP9 (-68%), TIMP-1 (-38%) and CRP (-23%) concentrations followed vitamin-D supplementation. DISCUSSION Vitamin-D insufficiency is associated with increased circulating MMP2,9 and CRP, correctable by supplementation. This finding provides a possible mechanism for tissue damage in chronic inflammatory conditions, including CHD and diabetes.
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Affiliation(s)
- P M Timms
- Department of Clinical Biochemistry, Barts and The London, Queen Mary's School of Medicine and Dentistry, University of London, London, UK
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13
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Leach TD, Kitiyakara C, Price CP, Stevens JM, Newman DJ. Prognostic significance of serum cystatin c concentrations in renal transplant recipients: 5-year follow-up. Transplant Proc 2002; 34:1152-8. [PMID: 12072302 DOI: 10.1016/s0041-1345(02)02818-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- T D Leach
- Wessex Renal & Transplant Unit St Mary's Hospital, Portsmouth, UK
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14
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Barakat K, Kennon S, Hitman GA, Aganna E, Price CP, Mills PG, Ranjadayalan K, North B, Clarke H, Timmis AD. Interaction between smoking and the glycoprotein IIIa P1(A2) polymorphism in non-ST-elevation acute coronary syndromes. J Am Coll Cardiol 2001; 38:1639-43. [PMID: 11704375 DOI: 10.1016/s0735-1097(01)01610-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES The goal of this study was to determine the interaction between smoking and the glycoprotein IIIa P1(A2) polymorphism in patients admitted with non-ST-elevation acute coronary syndromes (ACS). BACKGROUND An increased incidence of the P1(A2) polymorphism in smokers presenting with ST-elevation acute myocardial infarction (AMI) has recently been reported. We, therefore, postulated that, as a consequence of this interaction, fewer smokers with the P1(A2) polymorphism would present with non-ST-elevation ACS. METHODS We performed a prospective cohort analysis of 220 white Caucasoid patients admitted with non-ST-elevation ACS fulfilling Braunwald class IIIb criteria for unstable angina who were stratified by smoking status. RESULTS There were twice as many nonsmokers as smokers. Nonsmokers compared with smokers were older (mean [SD]; 63.9 [11.2] vs. 57.6 [10.3]; p < 0.0001), more likely to have had a previous admission with unstable angina (24.3% vs. 13.2%; p = 0.051) and AMI (45.8% vs. 30.3%; p < 0.026), more likely to have undergone revascularization (24.3% vs. 1.8%; p = 0.028) and were more likely to be on aspirin on admission (60.4% vs. 44.7%; p = 0.026). The proportion of nonsmokers positive for the P1(A2) polymorphism was equivalent to that expected for this population but was significantly reduced in smokers (28.7% vs. 10%; Pearson chi-square = 9.09, p = 0.0026). In a logistic regression model, the odds ratio (OR) for being positive for the P1(A2) polymorphism was significantly reduced by smoking (OR [interquartile range]: 0.26 [0.11 to 0.62]; p = 0.0026). CONCLUSIONS There is a significant reduction in the P1(A2) polymorphism in smokers admitted with non-ST-elevation ACS compared with nonsmokers, which suggests an interaction between smoking and this polymorphism.
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Affiliation(s)
- K Barakat
- Department of Cardiology, Bart's and the London NHS Trust, London, United Kingdom.
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15
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Kennon S, Barakat K, Hitman GA, Price CP, Mills PG, Ranjadayalan K, Cooper J, Clark H, Timmis AD. Angiotensin-converting enzyme inhibition is associated with reduced troponin release in non-ST-elevation acute coronary syndromes. J Am Coll Cardiol 2001; 38:724-8. [PMID: 11527624 DOI: 10.1016/s0735-1097(01)01426-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVES This study was done to determine the effects of angiotensin-converting enzyme (ACE) inhibition and other clinical factors on troponin release in non-ST-elevation acute coronary syndrome (ACS). BACKGROUND Troponin is now widely used as a marker of risk in ACS, but determinants of its release have not been defined. METHODS This was a prospective cohort study of 301 consecutive patients admitted with non-ST-elevation ACS. Baseline clinical data were recorded, ACE gene polymorphism was determined and serial blood samples were obtained for troponin-I assay. RESULTS Significant troponin-I release (>0.1 microg/l) was detected in 93 (31%) patients. Pretreatment with ACE inhibitors, recorded in 53 patients (17.6%), independently reduced the odds of troponin-I release (odds ratio 0.25; 95% confidence intervals 0.10 to 0.64) and was associated with lower maximum troponin-I concentrations (median [interquartile range]) compared with patients not pretreated with ACE inhibitors (0.44 microg/l [0.19 to 2.65 microg/l] vs. 4.18 microg/l [0.91 to 12.41 microg/l], p = 0.01). Pretreatment with aspirin, recorded in 173 patients (57.5%), did not significantly reduce the odds of troponin-I release after adjustment but was associated with lower maximum troponin-I concentrations compared with patients not pretreated with aspirin (2.31 microg/l [0.72 to 8.02 microg/l] vs. 5.85 microg/l [1.19 to 12.79 microg/l], p = 0.05). The ACE genotyping (n = 268) showed 81 patients (30%) DD homozygous and 77 (29%) II homozygous. There was no association between ACE genotype and troponin release. CONCLUSIONS We conclude that ACE inhibition reduces troponin release in non-ST-elevation ACS. This is likely to be mediated by the beneficial effects of treatment on vascular reactivity and the coagulation system.
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Affiliation(s)
- S Kennon
- Department of Cardiology, St. Bartholomew's and the Royal London School of Medicine and Dentistry, Queen Mary, University of London, London, United Kingdom.
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16
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Price CP. Microarrays: the reincarnation of multiplexing in laboratory medicine, but now more relevant? Clin Chem 2001; 47:1345-6. [PMID: 11468219] [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: 02/20/2023]
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17
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Holownia P, Perez-Amodio S, Price CP. Effect of poly(ethylene glycol), tetramethylammonium hydroxide, and other surfactants on enhancing performance in a latex particle immunoassay of C-reactive protein. Anal Chem 2001; 73:3426-31. [PMID: 11476244 DOI: 10.1021/ac001530g] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [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: 11/28/2022]
Abstract
The influence of a variety and combination of both ionic surfactants and different chain lengths of the polyelectrolyte poly(ethylene glycol) (PEG) on the performance characteristics (with particular reference to signal response) of a homogeneous, latex agglutination immunoassay was investigated. The test analyte was human serum C-reactive protein (CRP), and the antibody reagent consisted of a sheep polyclonal anti-CRP IgG fraction covalently coupled to 50-nm-sized latex including a glycine-capped chloromethylstyrene shell. The amount and rate of immunoagglutination was monitored turbidimetrically after sample addition. It was found that 2.5 mmol/L concentrations of the small cationic surfactant tetramethylammonium hydroxide (TMH), when present alone, substantially increased both reaction rates and sensitivity in the lower clinical ranges of CRP concentration when compared to normally used assay conditions containing PEG and the anionic detergent Gafac. The nonspecific binding (NSB) was also found to be unchanged. Evidence is presented that the TMH enhances the actual antibody-antigen interaction as opposed to the known effects of other surfactants in immunocomplex dissociation or in maintenance of colloidal stability. We suggest that the enhancement seen with TMH could be an alternative to PEG and may provide a new means of further extending detection limits. The utility of this type of immunoassay technology could therefore be increased whenever clinically required.
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Affiliation(s)
- P Holownia
- Department of Clinical Biochemistry, St. Bartholomews and Royal London Hospital's School of Medicine and Dentistry, UK.
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18
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Perez-Amodio S, Holownia P, Davey CL, Price CP. Effects of the ionic environment, charge, and particle surface chemistry for enhancing a latex homogeneous immunoassay of C-reactive protein. Anal Chem 2001; 73:3417-25. [PMID: 11476243 DOI: 10.1021/ac001529h] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [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: 11/28/2022]
Abstract
The role of the solution environment for a light-scattering, latex-particle-enhanced, homogeneous immunoassay of C-reactive protein (CRP) has been investigated in order to assess and optimize the immunoagglutination response. Latex particles of 50-170-nm sizes were covalently coupled with an IgG polyclonal antibody and subjected to an extensive optimization regime. This consisted of conditions responsible, in different degrees, for the principal attractive/repulsive forces affecting both colloidal stability and the antibody/antigen interaction: particle size, antibody concentration, ionic strength and species, pH, and amino acid chemistry of the particle surface. Careful control of these parameters was found to be necessary to achieve the desired effects of balancing high colloidal stability in the absence of antigen but promoting a rapid, sensitive, and dose-dependent agglutination with pathological serum samples. In addition, the estimation of fundamental properties governing intermolecular interaction (i.e. the "Hamaker" constant and critical coagulation concentration) was attempted to order to investigate a simple, practical means of defining a colloidal/immunoassay system under "real conditions" as well as "real time". It is concluded that because each antibody system is unique, a similar optimization should be performed in diagnostic immunoassays of this type to maximize their clinical utility.
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Affiliation(s)
- S Perez-Amodio
- St. Bartholomew's and Royal London Hospital's School of Medicine and Dentistry, Department of Clinical Biochemistry, UK
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19
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Abstract
BACKGROUND Cystatin C is a low molecular weight protein thought to be synthesised by all nucleated cells and freely filtered by the kidney. It has been proposed as a marker for GFR; however, it has been suggested that there may be limitations to its use, because it may be over-expressed in some tumour cells and the abnormal tissue growth may also lead to an increased circulating level. METHODS We investigated the serum cystatin C levels in 60 patients with myeloma, comparing results with those for serum creatinine, beta(2)-microglobulin and the paraprotein concentration. RESULTS We found no correlation between cystatin C and the paraprotein concentration in these patients. CONCLUSION These results suggest that disease burden does not correlate to the circulating level of cystatin C in patients with myeloma.
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Affiliation(s)
- H Finney
- Department of Clinical Biochemistry, The Royal London Hospital, Barts and The London NHS Trust, Whitechapel, E1 1BB, London, UK.
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20
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Price CP. Point-of-care testing. Impact on medical outcomes. Clin Lab Med 2001; 21:285-303. [PMID: 11396084] [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: 02/20/2023]
Abstract
There is now clear evidence that POCT has a positive benefit on morbidity and mortality. In addition, there are other tangible benefits that may themselves influence morbidity and mortality, e.g., reduced blood sample requirement in pediatrics, reduced length of stay, and greater doctor and patient satisfaction. These benefits accrue from the ability to make decisions and implement the appropriate intervention more quickly. It has also been demonstrated that POCT can facilitate improved patient motivation and satisfaction and thereby compliance with a prescribed disease management strategy. Improvement in health outcome, morbidity, and mortality can only be achieved, however, when the diagnostic and therapeutic interventions operate in concert. A review of the literature on medical outcomes of POCT has demonstrated the complexity of establishing evidence and the paucity of robust literature that exists at the present time. It is hoped, however, that the reader will appreciate how important it is to stress the role of a diagnostic test in decision making, to ensure that decisions are made and that benefits will be achieved. From a more pragmatic standpoint, however, it is hoped the reader will see the potential value of the arguments put forward in favor of implementing POCT when submitting a business case to a funding authority; the fact that the cost of POCT may be greater should not be a deterrent.
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Affiliation(s)
- C P Price
- Department of Clinical Biochemistry, St. Bartholomew's and Royal London School of Medicine and Dentistry, London, United Kingdom.
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Affiliation(s)
- C P Price
- Barts and London NHS Trust, Whitechapel, London E1 1BB.
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22
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Price CP, Allard J, Davies G, Dawnay A, Duffy MJ, France M, Mandarino G, Ward AM, Patel B, Sibley P, Sturgeon C. Pre- and post-analytical factors that may influence use of serum prostate specific antigen and its isoforms in a screening programme for prostate cancer. Ann Clin Biochem 2001; 38:188-216. [PMID: 11392495 DOI: 10.1258/0004563011900632] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- C P Price
- Department of Clinical Biochemistry, St. Bartholomew's & Royal London School of Medicine and Dentistry, UK.
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23
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Abstract
OBJECTIVES This study was designed to assess the interaction between aspirin and C-reactive protein (CRP) release in unstable angina. BACKGROUND C-reactive protein release in acute coronary syndromes may be a response to myocardial necrosis or may reflect the inflammatory process that drives atherogenesis. Aspirin has the potential to influence CRP release, either by its anti-inflammatory activity or by reducing myocardial necrosis. The clinical significance of this potential interaction has not previously been tested. METHODS We conducted a prospective cohort study of 304 consecutive patients admitted with non-ST-elevation acute coronary syndromes. Serial blood samples were obtained for CRP and troponin I assay. End points were cardiac death and nonfatal myocardial infarction during follow-up for 12 months. RESULTS A total of 174 patients (57%) were taking aspirin before admission. Patients taking aspirin had lower troponin I concentrations throughout the sampling period, only 45 (26.0%) having concentrations >0.1 mg/l compared with 48 (37.8%) patients not taking aspirin (p = 0.03). Maximum CRP concentrations were also lower in patients taking aspirin (8.16 mg/l [3.24 to 24.5]) than in patients not taking aspirin (11.3 mg/l [4.15 to 26.1]), although the difference was not significant. However, there was significant interaction (p = 0.04) between prior aspirin therapy and the predictive value of CRP concentrations for death and myocardial infarction at 12 months. Thus, odds ratios (95% confidence intervals) for events associated with an increase of 1 standard deviation in maximum CRP concentration were 2.64 (1.22-5.72) in patients not pretreated with aspirin compared with 0.98 (0.60-1.62) in patients pretreated with aspirin. CONCLUSIONS The association between CRP and cardiac events in patients with unstable angina is influenced by pretreatment with aspirin. Modification of the acute-phase inflammatory responses to myocardial injury is the major mechanism of this interaction.
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Affiliation(s)
- S Kennon
- Department of Cardiology, Bart's and the London NHS Trust, United Kingdom.
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24
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Hicks JM, Haeckel R, Price CP, Lewandrowski K, Wu AH. Recommendations and opinions for the use of point-of-care testing for hospitals and primary care: summary of a 1999 symposium. Clin Chim Acta 2001; 303:1-17. [PMID: 11163017 DOI: 10.1016/s0009-8981(00)00400-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [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: 10/18/2022]
Abstract
As part of a symposium on laboratory medicine, a colloquium on point-of-care testing was held in June 1999 where four experts were invited to produce recommendations and opinions on the use of point-of-care testing under various clinical venues. Each commented on costs for providing POCT services. A total of eleven recommendations and four opinions were rendered and discussed in an open forum. While one expert concluded that some forms of POCT are less expensive than central laboratory testing if entire laboratory workstations are eliminated, another expert suggested that POCT offered little advantage if rapid transport systems are available. A recommendation was made that POCT be considered for analytes that have a required reporting turnaround time of <30 min, and that the goals for precision and accuracy should be dictated by the clinical need and not by analytical limitations. Recommendations for POCT in specific clinical situations include use of glycated hemoglobin and urine albumin testing with personal glucose monitoring at the time of consultation, use of glycated albumin for gestational diabetes, leukocyte esterase and nitrite testing in urine to screen for urinary tract infections, coagulation tests for monitoring patients on oral anticoagulant therapy and in the operating room, testing for H. pylori for patients with dyspepsia, and cardiac markers and urine drugs-of-abuse testing in the emergency department.
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Affiliation(s)
- J M Hicks
- Department of Laboratory Medicine, Children's National Medical Center and the George Washington University School of Medicine, Washington, DC 20010, USA
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25
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Liow EW, Keay PJ, Wang RY, Holownia P, Price CP. Development of a charged-coupled device-based light-scattering instrument for the detection of C-reactive protein using particle-enhanced immunoassay. Biomed Instrum Technol 2001; 35:36-45. [PMID: 11233307] [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: 02/19/2023]
Abstract
A novel light-scattering instrument has been developed for rapid detection of immunoreactions in test latex particle-enhanced immunoassays. The detector consists of a flat-field grating and a charge-coupled device mounted on a rotating platform, and the detector measures a continuous spectrum from 350 nm to 735 nm at 440 polar angles with a resolution of 0.5 degrees. Optimal detection for rates of immunoreaction were determined by intensity of scattered light at different angles. Instrumental precisions were all shown to fall within 5% of the target relative standard deviation limits. The accuracy of the instrument was confirmed using monodispersed latex particles of known size and shape. The initial results showed the possibility of a sensitive and accurate detection of C-reactive protein throughout the range of clinical interest, thus demonstrating a significant potential for biomedical applications.
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Affiliation(s)
- E W Liow
- Research Centre, Faculty of Science, Technology and Design, University of Luton, Luton, United Kingdom
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26
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Abstract
Protein S-100 beta has been suggested as a prognostic marker in traumatic brain injury. However, little is known of its behaviour in the immediate post-injury period. With Ethics Committee approval, we recruited 30 patients with a history of head injury presenting to our Accident and Emergency Department. Blood was taken on arrival and at four hours post-injury. Serum S-100 beta was estimated using an immunoluminometric assay. Levels of S-100 beta were seen to fall rapidly with time. Half-time was distributed non-parametrically with a median of 198 minutes. Using the Mann-Whitney U test we found a statistically significant difference between non-desirable (Glasgow Outcome Score 1-3) and desirable (Glasgow Outcome Score 4-5) outcome on admission (p = 0.0155) but not at four hours (p = 0.1336). Levels of S-100 beta fell rapidly after its release following traumatic brain injury. Time after injury is therefore critical in assessing the significance of levels of S-100 beta, and sampling should be as early as possible to gain maximum information. If S-100 beta is to be assessed as a monitor of ongoing brain injury in the intensive therapy unit sampling must be frequent (e.g. every 4 hours) to be able to detect rises in serum levels before they have decayed to baseline.
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Affiliation(s)
- R G Jackson
- Academic Department of Anaesthesia and Intensive Care, Royal London Hospital, Whitechapel, London, UK
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27
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Price CP. Evidence-based laboratory medicine: supporting decision-making. Clin Chem 2000; 46:1041-50. [PMID: 10926881] [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: 02/17/2023]
Abstract
There is an implicit acceptance that an evidence-based culture underpins the practice of laboratory medicine, in part because it is perceived as the scientific foundation of medicine. However, several reviews of specific test procedures or technologies have shown that the evidence base is limited and in many cases flawed. One of the key deficiencies in the scientific literature on diagnostic tests often is the absence of an explicit statement of the clinical need, i.e., the clinical or operational question that the use of the test is seeking to answer. Several reviews of the literature on specific procedures have also demonstrated that the experimental methodology used is flawed with, in some cases, significant bias being introduced. Despite these limitations it is recognized that a more evidence-based approach will help in the education and training of health professionals, in the creation of a research agenda, in the production of guidelines, in the support of clinical decision-making, and in resource allocation. Furthermore, as knowledge and technologies continue to be developed, an evidence-based strategy will be critical to harnessing these developments.
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Affiliation(s)
- C P Price
- Department of Clinical Biochemistry, St. Bartholomew's and The Royal London School of Medicine & Dentistry, Turner Street, London E1 2AD, United Kingdom.
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Abstract
The assessment of the glomerular filtration rate (GFR) is the most commonly used test of renal function. The accepted reference procedure employs an exogenous clearance marker whilst the most popular test is that of serum or plasma creatinine. All of these tests have limitations, although the surrogate endogenous markers are the most practical. Cystatin C, a low molecular weight protein which can be measured by light scattering immunoassay, possesses many of the attributes required of the ideal GFR marker. Data on reference ranges indicate that circulating cystatin C levels reflect the variation in GFR throughout life and the marker demonstrates a better correlation with the reference procedure than serum creatinine.
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Affiliation(s)
- C P Price
- Department of Clinical Biochemistry, St Bartholomew's and the Royal London School of Medicine and Dentistry, Turner Street, E1 2AD, London, UK.
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Cousins CM, Holownia P, Hawkes JJ, Limaye MS, Price CP, Keay PJ, Coakley WT. Plasma preparation from whole blood using ultrasound. Ultrasound Med Biol 2000; 26:881-888. [PMID: 10942835 DOI: 10.1016/s0301-5629(00)00212-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A technique to efficiently separate plasma from human whole blood is described. Essentially, 3-mL samples are held on the axis of a tubular transducer and exposed for 5.7 min to an ultrasonic standing wave. The cells concentrate into clumps at radial separations of half wavelength. The clumps grow in size and sediment under gravity. A distinct plasma/cell interface forms as the cells sediment. The volume of clarified plasma increases with time. The separation efficiencies of transducers of 29-mm and 23-mm internal diameters driven, by test equipment, at radial resonances of 3.4 and 1.5 MHz, respectively, were compared. The average efficiency of separation was 99.6% at 1.5 MHz and 99.4% with the 3.4-MHz system. The cleared plasma constituted 30% of the sample volume at 1.5 MHz and 25% at 3. 4 MHz. There was no measurable release of haemoglobin or potassium into the suspending phase, indicating that there was no mechanical damage to cells at either frequency. A total of 114 samples from volunteers and patients were subsequently clarified in a 1.5-MHz system driven by an integrated generator. The average efficiency of clarification of blood was 99.76% for the latter samples. The clarification achieved is a significant improvement on that previously reported (98.5%) for whole blood exposed to a planar ultrasonic standing wave field (Peterson et al. 1986). We have, therefore, now achieved a six-fold reduction of cells in plasma compared to previous results.
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Affiliation(s)
- C M Cousins
- School of Biosciences, Cardiff University, Main Building, Park Place, Wales CF1 3TL., Cardiff, UK
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30
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Tupper-Carey DA, Newman DJ, Price CP, Walesby RK, Ridout DA, Feneck RO. How silent is perioperative myocardial ischemia? A hemodynamic, electrocardiographic, and biochemical study in patients undergoing coronary artery bypass graft surgery. J Cardiothorac Vasc Anesth 2000; 14:144-50. [PMID: 10794332 DOI: 10.1016/s1053-0770(00)90008-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
OBJECTIVE To analyze the relationship among Holter electrocardiogram (ECG) recordings, hemodynamic measurements indicative of global myocardial oxygen balance, and serum cardiac troponin I concentrations (cTnI) in the early postoperative period after coronary artery bypass graft (CABG) surgery. DESIGN Prospective observational study. SETTING University teaching hospital. PARTICIPANTS Thirty patients undergoing CABG surgery. INTERVENTIONS ECG measurements consisted of Holter and standard ECG recordings. Hemodynamic measurements included heart rate, systolic and diastolic blood pressure (SBP, DBP), pulmonary capillary wedge pressure, and cardiac index (CI). Derived indices included tension time index (TTI), rate-pressure product, pressure work index (PWI), and endocardial viability ratio (EVR). Serial measurements of cTnI concentrations were measured postoperatively; the area under the cTnI concentration time curve was calculated for each patient (AUC cTnI). MEASUREMENTS AND MAIN RESULTS Episodes of myocardial ischemia were associated with small but significant rises in SBP (p = 0.01), DBP (p = 0.001), and TTI (p = 0.005) compared with periods without ischemia in the same patients. Serum cTnI concentrations 24 hours after cardiopulmonary bypass (p = 0.03) and AUCcTnI (p = 0.01) values were greater in patients who developed ECG myocardial ischemia compared with patients who did not. CONCLUSIONS The small changes in hemodynamics seen, although statistically significant, are unlikely to be the primary cause of the ischemia. They more likely reflect an independent process that causes or occurs as a result of ischemic episodes. Ischemic episodes detected by the Holter monitor are associated with significant release of cardiac troponin from the myocardium.
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Affiliation(s)
- D A Tupper-Carey
- Department of Anaesthesia, St. Bartholomews and the London Chest Hospital, Royal London School of Medicine and Dentistry, United Kingdom
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31
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Abstract
There has been interest for a number of years in the possibility of separating blood into cells and plasma by methods other than centrifugation, so that the plasma can be analysed on-line. Cells in whole blood normally occupy about 45% of the suspension volume. It has been shown with a number of different cell types, such as yeast and bacteria, that for concentrations of this order the cells are not as efficiently harvested by ultrasound as those for lower concentrations. In this study, removal of cells from 3-4 ml whole blood volumes has been examined in ultrasonic standing wave fields from tubular transducers driven at a frequency of 1.6 MHz. Samples of whole human blood (n = 11) from two volunteers have been processed by three tubular transducers where high levels of cell removal, 99.7% on average, have been demonstrated with high reproducibility between samples as well as for different transducers.
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Affiliation(s)
- C M Cousins
- School of Biosciences, Cardiff University, UK.
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Abstract
Serum cystatin C measurement has been previously shown by ourselves and others to be a better indicator of changes in glomerular filtration rate (GFR) than serum creatinine. However, the available literature on reference values for cystatin C concentration remains surprisingly sparse; we thus set out to determine an adult reference range. Blood was taken from 309 healthy blood donors and creatinine and cystatin C concentrations were measured using commercially available automated methodologies. In addition, predicted creatinine clearances were calculated using the Cockcroft and Gault formula. The 95% reference intervals for creatinine, predicted creatinine clearance and cystatin C for all blood donors, regardless of gender, were 68-118 mumol/L, 58-120 ml/min/1.73 m2 and 0.51-0.98 mg/L, respectively. For women, the intervals were 68-98 mumol/L, 60-119 ml/min/1.73 m2 and 0.49-0.94 mg/L; for men, they were 78-123 mumol/L, 57-122 ml/min/1.73 m2 and 0.56-0.98 mg/L. This mean 95% reference interval for cystatin C in all donors under 50 years of age was 0.53-0.92 mg/L; for those over 50 years of age it was 0.58-1.02 mg/L. The small difference between make and female ranges meant that a single reference range for cystatin C could be established for all adults under 50 years of age without adjustment for body surface area. Serum cystatin C measurement offers a simpler and more sensitive screening test than serum creatinine for early changes in GFR.
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Affiliation(s)
- H Finney
- Department of Clinical Biochemistry, St Bartholomew's and The Royal London School of Medicine and Dentistry, UK
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Finney H, Newman DJ, Thakkar H, Fell JM, Price CP. Reference ranges for plasma cystatin C and creatinine measurements in premature infants, neonates, and older children. Arch Dis Child 2000; 82:71-5. [PMID: 10630919 PMCID: PMC1718178 DOI: 10.1136/adc.82.1.71] [Citation(s) in RCA: 195] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
AIM To establish a reference range in the paediatric population for the new glomerular filtration rate (GFR) marker, cystatin C, and to compare it with that of creatinine. METHODS Cystatin C and creatinine were measured by particle enhanced nephelometric immunoassay (PENIA) and fixed interval Jaff¿e methods, respectively, in 291 children aged 1 day to 17 years, including 30 premature infants with gestational ages ranging from 24 to 36 weeks. RESULTS In the premature infants, concentrations of both cystatin C and creatinine were significantly raised compared with term infants, with cystatin C concentrations being between 1.10 and 2.06 mg/litre and creatinine between 32 and 135 micromol/litre. In premature infants, there was no significant relation between gestational age and cystatin C or creatinine concentration. Creatinine concentrations fell to a nadir at 4 months of age, rising gradually to adult values by about 15-17 years of age, in contrast to cystatin C, which fell to a mean concentration of 0.80 mg/litre by the 1st year of life, and remained constant throughout adulthood up to the age of 50 years. Neither analyte showed any influence of sex. CONCLUSION The measurement of cystatin C, rather than creatinine, is more practical for monitoring GFR changes in the paediatric population.
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Affiliation(s)
- H Finney
- Department of Clinical Biochemistry, St Bartholomew's and The Royal London, School of Medicine and Dentistry, Turner Street, London E1 2AD, UK.
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34
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Abstract
The National Health Service in the United Kingdom was created in 1948, effectively becoming the main provider of healthcare and funded by the government from taxation. By the late 1970's, and despite many achievements, it was seen to be approaching a financial crisis. Radical reforms were introduced in the early 1990's bringing in general management, a split between purchaser and provider, and competition. Whilst there has been a change of government more recently several of these initiatives have been retained, with the exception of competition (the internal market) which has been abandoned. There is now a much greater focus on the quality of care with increased clinical and financial accountability. Laboratory medicine (generally termed pathology in the United Kingdom) has evolved to meet the demands of more patients, reducing turnaround times, a greater repertoire of investigations and a continuing improvement in productivity. There is an increasing focus on improved dialogue between the laboratory and the clinician covering interpretation of results, audit of services and outcomes, research and development and continuous education in the pursuit of a high quality service. The major challenges for the future focus on alternative modes of delivery, on issues relating to staffing and on quality of service, in the face of an ever increasing demand.
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Affiliation(s)
- C P Price
- Department of Clinical Biochemistry, St Bartholomew's and the Royal London School of Medicine and Dentistry, Turner Street, London, UK
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35
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Abstract
We have evaluated the analytical and clinical performance of an automated immunoassay for serum cardiac troponin I (Bayer Immuno 1TM, Bayer Diagnostics, Tarrytown, NY). The between batch imprecision was found to be between 1.2 and 3.2% over the concentration range 2.5 - 34.0 microg/L. The analytical range obtained from duplicate analysis of patient samples and defined as a coefficient of variation of 10% or less was 0.3 - 200 microg/L. The detection limit was found to be less than 0.1 microg/L. A method comparison with the Dade Stratus method (Dade Behring, Wilmington, DE) yielded regression statistics with a slope of 0.705 and an intercept of -0.260. An analysis of samples from 40 patients with renal failure demonstrated six with detectable levels of troponin I (0.2 - 1.9 microg/L). Samples from patients with paraproteinaemia did not demonstrate detectable troponin I (from n = 30); however, two patients with elevated rheumatoid factor titers (from n = 20) demonstrated a detectable amount of troponin I (0.1 and 0.2 microg/L). In a study of 100 patients admitted with acute chest pain and a diagnosis of unstable angina, 6 were subsequently diagnosed as having suffered a myocardial infarction. On admission the sensitivity and specificity of the troponin I results were 26.7% and 94.7%, respectively, moving to 100% and 83% 12 hours after admission.
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Affiliation(s)
- G H Clark
- Department of Clinical Biochemistry, Barts and The London NHS Trust, Whitechapel, London, UK
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36
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Foo Y, Price CP, Heins M. Book Review: Clinical Laboratory Diagnostics: Use and Assessment of Clinical Laboratory Results. Ann Clin Biochem 1999. [DOI: 10.1177/000456329903600428] [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] [Indexed: 11/16/2022]
Affiliation(s)
- Y Foo
- The Royal Free Hospital, London
| | - C P Price
- St Bartholomew's and the Royal London Hospital, London
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37
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Newman DJ, Olabiran Y, Bedzyk WD, Chance S, Gorman EG, Price CP. Impact of antibody specificity and calibration material on the measure of agreement between methods for cardiac troponin I. Clin Chem 1999; 45:822-8. [PMID: 10351991] [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: 02/12/2023]
Abstract
BACKGROUND Available assays for cardiac troponin I (cTnI) yield numerically different results. The aim of this study was to compare patient values obtained from four cTnI immunoassays. METHODS We studied the Stratus(R) II assay, the Opus(R) II assay, the Access(R) assay, and a research-only cTnI heterogeneous immunoassay that uses the Dade Behring aca(R) plus immunoassay system equipped with two new noncommercial monoclonal antibodies. Because the aca plus cTnI assay is for research only, we first evaluated and analytically validated it for serum and citrated plasma. Initially, each method was calibrated using the method-specific calibrator supplied by each manufacturer; however, the aca plus cTnI assay was calibrated using patient serum pools containing cTnI and selected on the basis of increased creatine kinase MB isoenzyme and with values assigned by use of the Stratus cTnI assay. For method comparisons, individual patient sample cTnI values were determined and compared with the Stratus II assay. RESULTS Passing and Bablock regression analysis yielded slopes of 1.44 (r = 0.96; n = 72) for the Opus II vs Stratus II assays; 0.07 (r = 0.91; n = 72) for the Access vs Stratus II assays; and 0.90 (r = 0.91, n = 72) for the aca plus vs Stratus II assays. The recalibration of each method with a Stratus II-assigned serum pool improved, but did not entirely eliminate, the slope differences between the different assays (range, 1.00-1.16). The observed scatter in the correlation curves remained. CONCLUSION There is a need to further explore the specificities of these assays with respect to the different circulating forms of cTnI.
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Affiliation(s)
- D J Newman
- Department of Clinical Biochemistry, St. Bartholomew's and the Royal London School of Medicine and Dentistry, Turner Street, London E1 2AD, UK. P.O. Box 6101, Newark, DE 19714-610
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38
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Price CP. Health technology assessment. Am Clin Lab 1999; 18:8. [PMID: 10539222] [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] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Affiliation(s)
- C P Price
- Department of Clinical Biochemistry, St. Bartholomew's and the Royal London School of Medicine & Dentistry, London, U.K.
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39
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Morgan CL, Price CP, Cohen SB, Madrigal JA, Newman DJ. Soluble CD8 stabilizes the HLA class I molecule by promoting beta2M exchange: analysis in real-time. Hum Immunol 1999; 60:442-9. [PMID: 10447404 DOI: 10.1016/s0198-8859(99)00014-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [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: 10/27/2022]
Abstract
Human soluble CD8 (sCD8) is secreted by activated CD8+/- cytotoxic T lymphocytes (CTLs). The immunological role of sCD8 is poorly defined, however. We have studied the influence of sCD8 on HLA class I interactions by real-time analysis. Using an optical biosensor we demonstrated that the binding of sCD8 to HLA-A2 promotes exchange of beta2-microglobulin (beta2m) in order to stabilize the complex. Kinetic analysis showed that sCD8 significantly increased the affinity (K(A)) of HLA-A2 for immobilized human beta2m; from 1.14 +/- 0.04 x 10(9) M(-1) in its absence, to 2.18 +/- 0.21 x 10(9) M(-1) following preincubation with sCD8. This suggests that the sCD8:HLA class I complex is unlikely to be degraded at the cell surface. Even in the presence of exogenous peptide (HLA-A2 specific or nonspecific), sCD8 has a stabilizing influence on the HLA class I molecule. These findings point to an immunosuppressive role for sCD8, because the binding of sCD8 to HLA class I would block the binding site for CTL-bound CD8 and, therefore, interfere with T cell activation and proliferation. This may have particular significance in pathological situations where elevated levels of sCD8 are found in extracellular fluids, and sCD8 may provide an alternative approach for immunosuppressive therapy.
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Affiliation(s)
- C L Morgan
- Anthony Nolan Research Institute, The Royal Free Hospital, London, UK.
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40
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Parsons M, Newman DJ, Pugia M, Newall RG, Price CP. Performance of a reagent strip device for quantitation of the urine albumin: creatinine ratio in a point of care setting. Clin Nephrol 1999; 51:220-7. [PMID: 10230554] [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: 02/12/2023] Open
Abstract
AIM We have evaluated the performance of a reagent strip (Clinitek, Bayer plc, Newbury) incorporating a novel dip and read device for the quantitation of the albumin: creatinine ratio together with their individual concentrations in urine. METHODS The performance was compared with that of a lateral flow device for the semi-quantitation of albumin (Micral II, Roche Diagnostics, Lewes) and also a laboratory based procedure. The device employs novel methods for both analytes, using a sulphonephthalein dye binding at pH 1.5 for albumin and the peroxidase-like activity of copper creatinine complexes. The color yields of the separate reaction pads are monitored with the Clinitek 50TM bench top urine chemistry analyzer and compared to a pre-programmed calibration algorithm. RESULTS The imprecision of the device was assessed by observing the discrepancy between duplicates in a total of 144 urine samples collected from patients with diabetes and/or renal disease; there were 10 discrepancies in the case of the albumin estimation (6.9%), 12 in the case of the creatinine estimation (12.5%) and 23 in the case of the albumin: creatinine ratio (16.0%). In the case of the Micral II, where 96 of the urines were analyzed there were 12 discrepancies (12.5%). When considered as a two-class test for albumin with a cut off of 20 mg/L the Clinitek gave a sensitivity of 95.4% with specificity of 78.9% and a positive predictive value of 87.4%. When analyzing four urines (two controls, two patient pools) with replicate analysis on the Clinitek system we found 100% agreement for the albumin estimation, 95% for creatinine and 96.7% for the albumin: creatinine for 60 analysis within a day and 100, 95 and 97.5% on single analyses each day for 20 days for the two urine controls. The discrepant results were always within one color block. When considering the albumin: creatinine ratio with a cut off of < 30 mg/g the Clinitek gave a sensitivity of 76.3% with a specificity of 89.1% and a positive predictive value of 89.7%. CONCLUSION The Clinitek system provides a reliable means to screen for microalbuminuria with the opportunity of a semi-quantitative assessment when microalbuminuria is found.
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Affiliation(s)
- M Parsons
- Department of Clinical Biochemistry, St. Bartholomew's, London, UK
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41
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Parsons MP, Newman DJ, Newall RG, Price CP. Validation of a point-of-care assay for the urinary albumin:creatinine ratio. Clin Chem 1999; 45:414-7. [PMID: 10053047] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Affiliation(s)
- M P Parsons
- St. Bartholomew's and the Royal London School of Medicine and Dentistry, Turner Street, London E1 2AD, UK
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42
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Price CP, Calvin J, Walker SA, Trull A, Newman DJ, Gorman EG. A rapid and sensitive automated light scattering immunoassay for serum C-reactive protein and the definition of a reference range in healthy blood donors. Clin Chem Lab Med 1999; 37:109-13. [PMID: 10219497 DOI: 10.1515/cclm.1999.020] [Citation(s) in RCA: 7] [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: 11/15/2022]
Abstract
The increasing interest in the measurement of serum C-reactive protein in relation to the risk stratification of patients with chest pain has demonstrated the need for more sensitive routine methods of measurement and an accurate definition of the reference range. We report the determination of a reference range in serum samples from 491 blood donors using a particle enhanced turbidimetric immunoassay that has been modified to offer better imprecision within the reference range. The median values were found to be 2.40 and 2.20 mg/l for males and females, respectively with 95th percentile range of 1.20-5.20 and 0.40-5.40 mg/l, respectively.
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Affiliation(s)
- C P Price
- Department of Clinical Biochemistry, St Bartholomew's, London, UK.
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43
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Affiliation(s)
- R S Van Howe
- Medical College of Wisconsin, Department of Paediatrics, Minocqua, WI, USA.
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44
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Abstract
Characterisation of the kinetics of assembly and dissociation of the HLA class I heterotrimeric complex provides valuable insights into the relative contributions of each element to complex stability. However, to date there has been no real-time binding analysis on whole cells. Here we have developed an optical biosensor model to investigate the binding of class I HLA complexes on whole cells to human beta 2-microglobulin (beta 2m) and the effects of different HLA-specific peptides on this binding. We immobilised beta 2m on an IAsys biosensor surface and established conditions to analyse the binding of this to HLA-A2 expressing cells (T2 cells). Using 721.221 cells as an HLA negative control we showed that HLA-A2 binding was optimal using a) a carboxymethylated dextran surface and b) no growth factors or supplements in the culture medium at the binding event. Using these conditions we verified specificity of binding by inhibition of the reaction with free beta 2m and determined the dissociation rate constant for T2 cell binding to beta 2m (0.03 s-1). In addition, we demonstrated the ability of different HLA specific peptides to modulate cellular HLA-A2 binding to beta 2m. This is the first time that interactions of cell surface HLA class I molecules has been investigated using real-time analysis. Furthermore, our peptide analysis has shown that this model can be used to characterise peptide specific HLA-binding responses on the whole cell surface in real-time.
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45
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Price CP. AACC 50th anniversary retrospective. The evolution of immunoassay as seen through the journal Clinical Chemistry. American Association for Clinical Chemistry. Clin Chem 1998; 44:2071-4. [PMID: 9761236] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Affiliation(s)
- C P Price
- Department of Clinical Biochemistry, St. Bartholomew's and the Royal London School of Medicine & Dentistry, UK.
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46
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Abstract
BACKGROUND The affinity and specificity of protein reabsorption by proximal tubular cells have been investigated using techniques for monitoring endocytosis, demonstrating a high capacity but low affinity process. It is not known whether uptake is through binding to a single binding site/receptor with differing affinities, or if there are several classes of binding sites receptors, each specific for differing proteins or groups, such as, high or low molecular weight proteins. METHODS We have developed a novel technique for analyzing the kinetics of protein binding to tubular cells using a optical biosensor system. We have studied the binding of cultured LLCPK cells to albumin and RBP immobilized onto the sensor. By adding increasing concentrations of competing proteins [varying in molecular weight from 66,000 to 11,800 D and pI from 4.6 to 9.2 as represented by albumin, alpha1-microglobulin (alpha1M), retinol binding protein (RBP), cystatin C and beta2-microglobulin (beta2m)], specific and inhibitable cell binding was demonstrated. RESULTS Equilibrium constants, KA, could be calculated from the reciprocal of the protein concentration causing 50% inhibition in binding rate. These were: albumin = 8.0 x 10(4) M(-1), alpha1M = 2.0 x 10(5) M(-1), RBP = 2.7 x 10(4) M(-1), cystatin C = 2.0 x 10(4) M(-1), beta2m = 4.2 x 10(3) M(-1). There were no significant differences between the measured KA's whether RBP or albumin were immobilized on the surface. CONCLUSIONS All the proteins gave similar shaped inhibition profiles, suggesting that there is one binding site/receptor for all proteins studied, regardless of molecular weight or charge, but there are differing affinities for each protein.
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Affiliation(s)
- H Thakkar
- Department of Clinical Biochemistry, St. Bartholomew's and The Royal London School of Medicine and Dentistry, England, United Kingdom
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47
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Ortega-Vinuesa JL, Hidalgo-Álvarez R, Davey CL, Newman DJ, Price CP. Characterization of Immunoglobulin G Bound to Latex Particles Using Surface Plasmon Resonance and Electrophoretic Mobility. J Colloid Interface Sci 1998; 204:300-11. [PMID: 9698408 DOI: 10.1006/jcis.1998.5581] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The main objective of this work was the investigation of passive adsorption and covalent coupling of a polyclonal IgG and a monoclonal preparation of IgG against HSA, to a carboxyl latex particle. The functional activity of the coupled protein was then assessed by quantitative immunoassays for the antigen. Sensitized particles, with different protein coverage, were fully characterized using a range of different technologies, including electrophoretic mobility (µe), photon correlation spectroscopy, and surface plasmon resonance (SPR). The antibody-labeled particles were studied with respect to electrokinetic behavior in pH and ionic strength titration, stability, antibody functionality, and their perfomance in immunoaggregation reactions. Important differences were observed between the two sets of particle preparations throughout the series of experiments. The differences could be attributed to the coupling of the IgG molecules to the particles by the two different adsorption protocols. When proteins were chemically bound to the polymer surface it was necessary to activate the carboxyl groups with a carbodiimide (CDI) moiety that in our case was positively charged. The differences in characteristics between the adsorbed and the coupled antibody particles are thought to be due to the fact that in the covalent coupling protocol some CDI molecules remained linked to the particles, which altered the average electrical state of the outer layer in comparison with those samples where antibodies were physically adsorbed. On the other hand, the isoelectric point of the monoclonal antibody was lower (5.4 +/- 0.1) than the pI of the polyclonal antisera (6.9 +/- 0.9), which could explain why the IgG-latex complexes created with monoclonal molecules were colloidally more stable at neutral pH than those created with the polyclonal antisera. However, no immunoaggregation of antibody particles by the presence of antigen was found with the former. The use of SPR demonstrated that the equilibrium constants for the antibody-antigen recognition of the two antibody preparations were quite similar (KA polyclonal IgG = 2.8 10(8) M-1; KA monoclonal IgG = 9.5 10(7) M-1). These observations suggest that the lack of aggregation mediated by antigen demonstrated by the monoclonal antibody coupled to the latex particles may be due to this protein recognizing only one epitope in the HSA molecule. However, as the repulsive charge between antibody-latex particles counteracts the attractive forces between the antigen epitope and the antibody paratope, the greatest immunoaggregation was obtained when using latex particle-antibody complex with a low charge density (N) in the external layer. Copyright 1998 Academic Press.
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Affiliation(s)
- JL Ortega-Vinuesa
- Department of Applied Physics, Faculty of Sciences, University of Granada, Fuentenueva S/N, Granada, 18071, Spain
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48
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Price CP, Newman DJ, Blirup-Jensen S, Guder WG, Grubb A, Itoh Y, Johnson M, Lammers M, Packer S, Seymour D. First International Reference Preparation for Individual Proteins in Urine. IFCC Working Group on Urine Proteins. International Federation of Clinical Chemistry. Clin Biochem 1998; 31:467-74. [PMID: 9740968 DOI: 10.1016/s0009-9120(98)00036-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- C P Price
- Department of Clinical Biochemistry, St. Bartholomew's Royal London School of Medicine & Dentistry.
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Morgan CL, Newman DJ, Burrin JM, Price CP. The matrix effects on kinetic rate constants of antibody-antigen interactions reflect solvent viscosity. J Immunol Methods 1998; 217:51-60. [PMID: 9776574 DOI: 10.1016/s0022-1759(98)00092-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [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: 11/29/2022]
Abstract
This study describes the influence of different matrices on two model antibody-antigen interactions; that between beta2microglobulin and anti beta2microglobulin, and that of rabbit anti mouse Fc fragment (RAMFc) with mouse IgG. The matrices investigated were; phosphate-buffered saline pH 7.4 containing 0.05% Tween 20 detergent, horse serum, a 50:50 mixture of phosphate-buffered saline/Tween 20 and horse serum, and four glycerol solutions of differing concentrations. A recently developed optical biosensor, the IAsys, was used to monitor the interactions in real-time and provide precise determinations of k(ass), k(diss) and KA values. The results show that the rates of association and dissociation for the two different antibody:antigen models are significantly affected by the surrounding matrix. Glycerol of known viscosity was used as a matrix in both models to show that this effect is attributable to the viscosity as opposed to proteins present in the matrix. The viscosity of the matrix has also been shown to have an apparent influence upon the overall equilibrium/affinity constant for the interaction, with measurements of KA tending to increase with viscosity. The significant effects of matrix on kinetic rate constants for antibody-antigen interactions shown here have important implications in the use of immunoassays where non-equilibrium measurements are made in serum matrices.
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Affiliation(s)
- C L Morgan
- Department of Clinical Biochemistry, St Bartholomew's and the Royal London School of Medicine and Dentistry, UK
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50
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Morgan CL, Ruprai AK, Solache A, Lowdell M, Price CP, Cohen SB, Parham P, Madrigal JA, Newman DJ. The influence of exogenous peptide on beta2-microglobulin exchange in the HLA complex: analysis in real-time. Immunogenetics 1998; 48:98-107. [PMID: 9634473 DOI: 10.1007/s002510050409] [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: 11/30/2022]
Abstract
We used an optical biosensor to determine the relative binding affinity of peptides to purified HLA class I molecules. In this assay we monitor beta2-microglobulin (beta2m) exchange within the HLA-A2 molecule, whereby native beta2m in the complex is replaced by beta2m immobilized at the surface of the biosensor. Quantitative kinetic measurements permit us to obtain association rate (kass), dissociation rate (kdiss) and affinity constants (KA) for the beta2m exchange reaction, alone, (control) and in the presence of exogenous peptide. We tested a panel of six peptides which had been designed and synthesized with an HLA-A2 binding motif, and had also been tested by the T2-cell binding assay, along with control peptides. The biosensor results demonstrate that exogenous peptide influences the dynamics of beta2m exchange in a sequence-specific manner. Five of six peptides increased the association rate, decreased the dissociation rate, and significantly increased the affinity (KA=1. 55-1.88x10(9) M-1) of HLA-A2 for immobilized beta2m compared with the control (KA =1.14+/-0.04x10(9)M-1), demonstrating stabilization of the complex. One peptide was unable to stabilize the complex, as also shown in the T2 binding assay. However, analysis of peptide sequences demonstrated that the HLA-A2 secondary motif as well as primary motif residues are required for HLA-A2 stabilization. Further experiments demonstrated that beta2m exchange alone cannot stabilize the HLA class I complex at the cell surface until a peptide of sufficient binding affinity is bound. Hence kinetics equal to or below the control values in our biosensor assay probably represent an unstable complex in vivo. Unlike other methods described for the analysis of peptide stabilization, this approach is significantly faster, provides full kinetic analysis, and is simpler, since it requires no labeling of peptides. Furthermore, this may have important implications in the assessment of peptide vaccines.
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Affiliation(s)
- C L Morgan
- Anthony Nolan Research Institute, The Royal Free Hospital, London NW3 2QG, UK
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