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White NH, Quattrin T, Aubin LBS, Duggan WT, England RD, Fryburg JS. Efficacy and Safety of Inhaled Human Insulin (Exu hera ®) Compared to Subcutaneous Insulin in Children Ages 6 to 11 Years with Type 1 Diabetes Mellitus: Results of a 3-Month, Randomized, Parallel Trial. J Pediatr Endocrinol Metab 2020; 21:555-568. [PMID: 33600687 DOI: 10.1515/jpem-2008-210610] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AIM To compare the efficacy and safety of Exubera® (EXU) with subcutaneous (SC) insulin in children, ages 6-11 years, with type 1 diabetes mellitus. DESIGN AND METHODS 121 children were randomized to receive EXU or SC insulin, plus intermediate/ long-acting insulin for 12 weeks. Change in HbA1c was the primary efficacy endpoint. RESULTS Decreases from baseline HbA1c were comparable between treatment groups ( difference between adjusted mean decrease from baseline [EXU - SC insulin], -0.23 [95% CI, -0.49, 0.03]). Differences between groups on pulmonary function tests were small and not significant. Mild to moderate cough occurred in 24.6% of EXU versus 6.8% of SC insulin patients. The risk for hypoglycemia was comparable between EXU and SC insulin (relative risk 0.88 [95% CI, 0.71, 1.11]). Increased insulin antibodies with EXU were not associated with clinical findings. CONCLUSION The efficacy and safety profiles shown in this study are the foundation for further investigation of EXU in this population.
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Affiliation(s)
- Neil H White
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO,Washington, USA
| | - Teresa Quattrin
- Diabetes Center, Children's Hospital of Buffalo, State University of New York at Buffalo,NY, USA
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Ezekowitz MD, Pollack CV, Halperin JL, England RD, VanPelt Nguyen S, Spahr J, Sudworth M, Cater NB, Breazna A, Oldgren J, Kirchhof P. Apixaban compared to heparin/vitamin K antagonist in patients with atrial fibrillation scheduled for cardioversion: the EMANATE trial. Eur Heart J 2018; 39:2959-2971. [PMID: 29659797 PMCID: PMC6110194 DOI: 10.1093/eurheartj/ehy148] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 08/14/2017] [Accepted: 03/22/2018] [Indexed: 01/01/2023] Open
Abstract
Aim The primary objective was to compare apixaban to heparin/vitamin K antagonist (VKA) in patients with atrial fibrillation (AF) and ≤48 h anticoagulation prior to randomization undergoing cardioversion. Methods One thousand five hundred patients were randomized. The apixaban dose of 5 mg b.i.d. was reduced to 2.5 mg b.i.d. in patients with two of the following: age ≥ 80 years, weight ≤ 60 kg, or serum creatinine ≥ 133 µmol/L. To expedite cardioversion, at the discretion of the investigator, imaging and/or a loading dose of 10 mg (down-titrated to 5 mg) was allowed. The endpoints for efficacy were stroke, systemic embolism (SE), and death. The endpoints for safety were major bleeding and clinically relevant non-major (CRNM) bleeding. Results There were 1038 active and 300 spontaneous cardioversions; 162 patients were not cardioverted. Imaging was performed in 855 patients, and 342 received a loading dose of apixaban. Comparing apixaban to heparin/VKA in the full analysis set, there were 0/753 vs. 6/747 strokes [relative risk (RR) 0; 95% confidence interval (95% CI) 0-0.64; nominal P = 0.015], no SE, and 2 vs. 1 deaths (RR 1.98; 95% CI 0.19-54.00; nominal P > 0.999). In the safety population, there were 3/735 vs. 6/721 major (RR 0.49; 95% CI 0.10-2.07; nominal P = 0.338) and 11 vs. 13 CRNM bleeding events (RR 0.83; 95% CI 0.34-1.89; nominal P = 0.685). On imaging, 60/61 with thrombi continued randomized treatment; all (61) were without outcome events. Conclusions Rates of strokes, systemic emboli, deaths, and bleeds were low for both apixaban and heparin/VKA treated AF patients undergoing cardioversion. Clinical Trials.gov number NCT02100228.
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Affiliation(s)
- Michael D Ezekowitz
- Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, USA
- Lankenau Heart Center, Wynnewood, PA, USA
- Bryn Mawr Hospital, Bryn Mawr, PA, USA
| | | | | | | | | | - Judith Spahr
- Thomas Jefferson University, Philadelphia, PA, USA
| | | | | | | | - Jonas Oldgren
- Uppsala Clinical Research Centre and Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Paulus Kirchhof
- University of Birmingham Institute of Cardiovascular Sciences, SWBH and UHB NHS Trusts, Birmingham, UK
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Atkinson S, Lubaczewski S, Ramaker S, England RD, Wajsbrot DB, Abbas R, Findling RL. Desvenlafaxine Versus Placebo in the Treatment of Children and Adolescents with Major Depressive Disorder. J Child Adolesc Psychopharmacol 2018; 28:55-65. [PMID: 29185786 PMCID: PMC5771531 DOI: 10.1089/cap.2017.0099] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE To evaluate the short-term efficacy and safety of desvenlafaxine versus placebo in the treatment of children and adolescents with major depressive disorder (MDD). METHODS Outpatient children (7-11 years) and adolescents (12-17 years) who met DSM-IV-TR criteria for MDD and had screening and baseline Children's Depression Rating Scale-Revised (CDRS-R) total scores >40 were randomly assigned to 8 weeks of treatment with placebo, low exposure desvenlafaxine (20, 30, or 35 mg/day based on baseline weight), or higher exposure desvenlafaxine (25, 35, or 50 mg/day based on baseline weight). The primary efficacy endpoint was change from baseline in CDRS-R total score at week 8, analyzed using a mixed-effects model for repeated measures. Secondary efficacy assessments included Clinical Global Impressions-Severity and Clinical Global Impressions-Improvement scales. Safety assessments included adverse events and the Columbia-Suicide Severity Rating Scale. RESULTS The safety population included 363 patients (children, n = 109; adolescents, n = 254). No statistical separation from placebo was observed for either desvenlafaxine group for CDRS-R total score or for any secondary efficacy endpoint. At week 8, adjusted mean (standard error) changes from baseline in CDRS-R total score for the desvenlafaxine low exposure, desvenlafaxine high exposure, and placebo groups were -23.7 (1.1), -24.4 (1.1), and -22.9 (1.1), respectively. The incidence of adverse events was similar among groups. CONCLUSION Low and high exposure desvenlafaxine groups did not demonstrate efficacy for the treatment of MDD in children and adolescents in this double-blind, placebo-controlled trial. Desvenlafaxine (20-50 mg/day) was generally safe and well tolerated with no new safety signals identified in pediatric patients with MDD in this study.
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Affiliation(s)
| | | | | | | | | | | | - Robert L. Findling
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University and Kennedy Krieger Institute, Baltimore, Maryland
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Weihs KL, Murphy W, Abbas R, Chiles D, England RD, Ramaker S, Wajsbrot DB. Desvenlafaxine Versus Placebo in a Fluoxetine-Referenced Study of Children and Adolescents with Major Depressive Disorder. J Child Adolesc Psychopharmacol 2018; 28:36-46. [PMID: 29189044 PMCID: PMC5771543 DOI: 10.1089/cap.2017.0100] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVES To evaluate the short-term efficacy and safety of desvenlafaxine (25-50 mg/d) compared with placebo in children and adolescents with major depressive disorder (MDD). METHODS Outpatient children (7-11 years) and adolescents (12-17 years) who met DSM-IV-TR criteria for MDD and had screening and baseline Children's Depression Rating Scale-Revised (CDRS-R) total scores >40 were randomly assigned to 8-week treatment with placebo, desvenlafaxine (25, 35, or 50 mg/d based on baseline weight), or fluoxetine (20 mg/d). The primary efficacy endpoint was change from baseline in CDRS-R total score at week 8, analyzed using a mixed-effects model for repeated measures. Secondary efficacy endpoints included week 8 Clinical Global Impressions-Severity, Clinical Global Impressions-Improvement (CGI-I), and response (CGI-I ≤ 2). Safety assessments included adverse events, physical and vital sign measurements, laboratory evaluations, electrocardiogram, and the Columbia-Suicide Severity Rating Scale. RESULTS The safety population included 339 patients (children, n = 130; adolescents, n = 209). The primary endpoint, change from baseline in CDRS-R total score at week 8, did not statistically separate from placebo, for either desvenlafaxine (adjusted mean [standard error] change, -22.6 [1.17]) or fluoxetine (-24.8 [1.17]; placebo, -23.1 [1.18]). Week 8 CGI-I response rates were significantly greater for fluoxetine (78.2%; p = 0.017) than for placebo (62.6%); desvenlafaxine (68.7%) did not differ from placebo. Other secondary outcomes were consistent with those obtained with CDRS-R. Rates of treatment-emergent adverse events were comparable among treatment groups (desvenlafaxine, 60.0%; placebo, 70.5%; and fluoxetine, 64.3%). CONCLUSION Desvenlafaxine did not demonstrate efficacy for treating MDD in children and adolescents in this trial. Because neither desvenlafaxine nor the reference medication, fluoxetine, demonstrated a statistically significant difference from placebo on the primary endpoint, this was considered a failed trial and no efficacy conclusions can be drawn. Desvenlafaxine 25-50 mg/d was generally safe and well tolerated in children and adolescents in this study.
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Affiliation(s)
- Karen L. Weihs
- Department of Psychiatry, University of Arizona, Tucson, Arizona
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Delahanty LM, Riggs M, Klioze SS, Chew RD, England RD, Digenio A. Maximizing retention in long-term clinical trials of a weight loss agent: use of a dietitian support team. Obes Sci Pract 2016; 2:256-265. [PMID: 27708842 PMCID: PMC5043498 DOI: 10.1002/osp4.57] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/27/2016] [Accepted: 07/10/2016] [Indexed: 12/17/2022] Open
Abstract
Objective High‐attrition rates have been observed in long‐term clinical trials of weight loss agents. We evaluated the impact of an innovative retention programme on 1‐year retention. Methods Three Phase 3 global multicentre clinical trials evaluated the efficacy and safety of a CB1 receptor antagonist in subjects with BMI ≥ or = 27 kg/m2. The impact of a multifaceted retention programme including a dietitian screening interview, a comprehensive culturally adapted lifestyle modification programme, and a dietitian support system to maximize lifestyle adherence, was evaluated in 4,410 subjects from four subpopulations (non‐US English‐speaking, non‐English‐speaking, US‐without dietitian screening and US‐with dietitian screening) comprising 208 centres from 15 countries. Results The median proportion retained over the first year among subjects in three protocols was 82%. Non‐English‐speaking countries showed higher retention rates (89%) compared with the USA (73%) and non‐US English‐speaking (81%) countries. Within the USA, behavioural screening was associated with 29% reduction in dropout rate; for every five monthly teleconferences attended above 11, there was a 32% decrease in dropout rate. Conclusions This novel retention programme greatly improved upon reported retention rates of studies conducted with other weight loss agents in long‐term clinical trials. Its effectiveness should be confirmed in future trials.
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Affiliation(s)
- L M Delahanty
- Massachusetts General Hospital Diabetes Center Boston MA USA; Harvard Medical School Boston MA USA
| | | | - S S Klioze
- Pfizer Global Research and Development Groton CT USA
| | - R D Chew
- Pfizer Global Research and Development Groton CT USA
| | - R D England
- Pfizer Global Research and Development Groton CT USA
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Hegewald MJ, Jensen RL, Teeter JG, Wise RA, Riese RJ, England RD, Ahrens RC, Crapo RO, MacIntyre NR. Long-term intersession variability for single-breath diffusing capacity. ACTA ACUST UNITED AC 2011; 84:377-84. [PMID: 22213782 DOI: 10.1159/000334699] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 10/24/2011] [Indexed: 11/19/2022]
Abstract
BACKGROUND Characterizing long-term diffusing capacity (DL(CO)) variability is important in assessing quality control for DL(CO) equipment and patient management. Long-term DL(CO) variability has not been reported. OBJECTIVES It was the aim of this study to characterize long-term variability of DL(CO) in a cohort of biocontrols and to compare different methods of selecting a target value. METHODS Longitudinal DL(CO) monitoring of biocontrols was performed as part of the inhaled insulin development program; 288 biocontrols were tested twice monthly for up to 5 years using a standardized technique. Variability, expressed either as percent change or DL(CO) units, was assessed using three different target values. RESULTS The 90th percentile for mean intersession change in DL(CO) was between 10.9 and 15.8% (2.6-4.1 units) depending on the target value. Variability was lowest when the mean of all DL(CO) tests was used as the target value and highest when the baseline DL(CO) was used. The average of the first six DL(CO) tests provided an accurate estimate of the mean DL(CO) value. Using this target, the 90th percentile for mean intersession change was 12.3% and 3.0 units. Variability was stable over time and there were no meaningful associations between variability and demographic factors. CONCLUSIONS DL(CO) biocontrol deviations >12% or >3.0 units, from the average of the first six tests, indicate that the instrument is not within quality control limits and should be carefully evaluated before further patient testing.
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Affiliation(s)
- Matthew J Hegewald
- Division of Pulmonary and Critical Care Medicine, University of Utah School of Medicine and Intermountain Medical Center, Salt Lake City/Murray, Utah, USA
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Aronne LJ, Finer N, Hollander PA, England RD, Klioze SS, Chew RD, Fountaine RJ, Powell CM, Obourn JD. Efficacy and safety of CP-945,598, a selective cannabinoid CB1 receptor antagonist, on weight loss and maintenance. Obesity (Silver Spring) 2011; 19:1404-14. [PMID: 21293451 DOI: 10.1038/oby.2010.352] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [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: 11/09/2022]
Abstract
Three double-blind, placebo-controlled, three-parallel-group, multicenter phase 3 trials were conducted to assess the efficacy and safety of CP-945,598 for weight loss and weight-loss maintenance. Two trials were designed to be 2 years in duration (in obese and overweight patients) and one as a 1-year study (in obese and overweight patients with type 2 diabetes). However, the 2-year trials and the CP-945,598 development program were terminated before completion due to changing regulatory perspectives of CB1 receptor-related drugs. In total, 1,253 and 2,536 participants in the two 2-year multinational and North American studies were randomized to 10-mg CP-945,598 (n = 360; 718); 20-mg CP-945,598 (n = 534, 1,084) and placebo (n = 359, 734), respectively; and 975 participants were randomized to 10-mg CP-945,598 (n = 318); 20-mg CP-945,598 (n = 320); and placebo (n = 337) in the 1-year multinational diabetes trial. Baseline demographics were similar between treatment groups within each trial. One year of treatment with CP-945,598 resulted in a dose-related mean percentage reduction from baseline body-weight in all trials. A significant proportion of all participants also achieved 5% and 10% weight loss after 1 year. In participants with mainly well-controlled type 2 diabetes, the combination of lifestyle and CP-945,598 induced substantial improvements in glycemic control. The most frequent adverse events (AEs) for CP-945,598 were: diarrhea, nausea, nasopharyngitis, and headache. Self-reported experiences of anxiety and suicidal thoughts were higher with CP-945,598 than placebo, as were the incidence of depression and depressed mood. However, the reported increases in psychiatric symptoms were not consistently dose dependent.
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Affiliation(s)
- Louis J Aronne
- Weill Cornell Medical College, Cornell University, New York, New York, USA
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White NH, Quattrin T, St Aubin LB, Duggan WT, England RD, Fryburg JS. Efficacy and safety of inhaled human insulin (Exubera) compared to subcutaneous insulin in children ages 6 to 11 years with type 1 diabetes mellitus: results of a 3-month, randomized, parallel trial. J Pediatr Endocrinol Metab 2008; 21:555-68. [PMID: 18717242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
AIM To compare the efficacy and safety of Exubera (EXU) with subcutaneous (SC) insulin in children, ages 6-11 years, with type 1 diabetes mellitus. DESIGN AND METHODS 121 children were randomized to receive EXU or SC insulin, plus intermediate/long-acting insulin for 12 weeks. Change in HbA1c was the primary efficacy endpoint. RESULTS Decreases from baseline HbA1c were comparable between treatment groups (difference between adjusted mean decrease from baseline [EXU-SC insulin], -0.23 [95% CI, -0.49, 0.03]). Differences between groups on pulmonary function tests were small and not significant. Mild to moderate cough occurred in 24.6% of EXU versus 6.8% of SC insulin patients. The risk for hypoglycemia was comparable between EXU and SC insulin (relative risk 0.88 [95% CI, 0.71, 1.11]). Increased insulin antibodies with EXU were not associated with clinical findings. CONCLUSION The efficacy and safety profiles shown in this study are the foundation for further investigation of EXU in this population.
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Affiliation(s)
- Neil H White
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Drummond MB, Schwartz PF, Duggan WT, Teeter JG, Riese RJ, Ahrens RC, Crapo RO, England RD, Macintyre NR, Jensen RL, Wise RA. Intersession variability in single-breath diffusing capacity in diabetics without overt lung disease. Am J Respir Crit Care Med 2008; 178:225-32. [PMID: 18467511 DOI: 10.1164/rccm.200801-090oc] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE American Thoracic Society guidelines state that a 10% or greater intersession change in diffusing capacity of the lung (DL(CO)) should be considered clinically significant. However, little is known about the short-term intersession variability in DL(CO) in untrained subjects or how variability is affected by rigorous external quality control. OBJECTIVES To characterize the intersession variability of DL(CO) and the effect of different quality control methods in untrained individuals without significant lung disease. METHODS Data were pooled from the comparator arms of 14 preregistration trials of inhaled insulin that included nonsmoking diabetic patients without significant lung disease. A total of 699 participants performed repeated DL(CO) measurements using a highly standardized technique. A total of 948 participants performed repeated measurements using routine clinical testing. MEASUREMENTS AND MAIN RESULTS The mean intersession absolute change in DL(CO) using the highly standardized method was 1.45 ml/minute/mm Hg (5.64%) compared with 2.49 ml/minute/mm Hg (9.52%) in the routine testing group (P < 0.0001 for both absolute and percent difference). The variability in absolute intersession change in DL(CO) increased with increasing baseline DL(CO) values, whereas the absolute percentage of intersession change was stable across baseline values. Depending on the method, 15.5 to 35.5% of participants had an intersession change of 10% or greater. A 20% or greater threshold would reduce this percentage of patients to 1 to 10%. CONCLUSIONS Intersession variability in DL(CO) measurement is dependent on the method of testing used and baseline DL(CO). Using a more liberal threshold to define meaningful intersession change may reduce the misclassification of normal variation as abnormal change.
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Affiliation(s)
- Michael B Drummond
- Division of Pulmonary and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224, USA.
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Wise RA, Teeter JG, Jensen RL, England RD, Schwartz PF, Giles DR, Ahrens RC, MacIntyre NR, Riese RJ, Crapo RO. Standardization of the Single-Breath Diffusing Capacity in a Multicenter Clinical Trial. Chest 2007; 132:1191-7. [PMID: 17890472 DOI: 10.1378/chest.07-0455] [Citation(s) in RCA: 18] [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: 11/01/2022] Open
Abstract
BACKGROUND Standardization of the measurement of single-breath diffusing capacity of the lung for carbon monoxide (DLCO) is difficult to implement in multicenter trials as differences in equipment, training, and performance guidelines have led to high variability between and within centers. The safety assessment of inhalable insulin required the standardization of measurement of single-breath DLCO in multicenter clinical trials to optimize test precision. METHODS This was an open-label, 24-week, parallel-group, outpatient study of inhaled human insulin in participants with type 1 diabetes who were randomly assigned to receive treatment with daily premeal inhaled or subcutaneous (SC) insulin for 12 weeks, followed by SC insulin for 12 weeks. Monitoring of single-breath DLCO using standardized methodology was performed. Standardization included uniform instrumentation, centrally trained study coordinators, and centralized data monitoring and review of quality control. Sites received feedback within 24 h for any tests of unacceptable quality with recommendations for improvement. RESULTS A total of 226 study participants at 33 sites completed 11,335 DLCO efforts during 4,797 test sessions; 3,607 (75.2%) and 4,581 (95.5%) of all testing sessions yielded two American Thoracic Society-acceptable efforts that varied by < 1 and 2 mL/min/mm Hg, respectively. Only 65 sessions produced one or fewer acceptable efforts. The root mean square intrasubject coefficient of variation in DLCO at the end of the comparative dosing phase was 6.01%. CONCLUSIONS The standardized methodology employed in this study demonstrates the feasibility of collecting high-quality single-breath DLCO data in the setting of a multicenter clinical trial with reliability that is comparable to spirometry.
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Affiliation(s)
- Robert A Wise
- Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Jensen RL, Teeter JG, England RD, Howell HM, White HJ, Pickering EH, Crapo RO. Sources of Long-term Variability in Measurements of Lung Function. Chest 2007; 132:396-402. [PMID: 17400686 DOI: 10.1378/chest.06-1999] [Citation(s) in RCA: 32] [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: 11/01/2022] Open
Abstract
BACKGROUND The objective of the study was to characterize the biological and technical components of variability associated with longitudinal measurements of FEV(1) and carbon monoxide diffusing capacity (Dlco). Variability was apportioned to subject and instrument for five commercially available pulmonary function testing (PFT) systems: Collins CPL (Ferraris Respiratory; Louisville, CO); Morgan Transflow Test PFT System (Morgan Scientific; Haverhill, MA); SensorMedics Vmax 22D (VIASYS Healthcare; Yorba Linda, CA); Jaeger USA Masterscreen Diffusion TP (VIASYS Healthcare; Yorba Linda, CA); and Medical Graphics Profiler DX System (Medical Graphics Corporation; St. Paul, MN). METHODS This was a randomized, replicated cross-over, single-center methodology study in 11 healthy subjects aged 20 to 65 years. Spirometry and Dlco measurements were performed at baseline, 3 months, and 6 months. Repetitive simulations of FEV(1) and Dlco were performed on the same instruments on four occasions over a 90-day period using a spirometry waveform generator and a Dlco simulator. RESULTS The coefficient of variation associated with repetitive measurements of FEV(1) or Dlco in subjects was consistently larger than that associated with repetitive simulated waveforms across the five instruments. Instrumentation accounted for 13 to 58% of the total FEV(1) and 36 to 70% of the total Dlco variability observed in subjects. Sample size estimates of hypothetical studies designed to detect treatment group differences of 0.050 L in FEV(1) and 0.5 mL/min/mm Hg in Dlco varied as much as four times depending on the instrument utilized. CONCLUSIONS These results provide a semiquantitative assessment of the biological and technical components of PFT variability in a highly standardized setting. They illustrate how instrument choice and test variability can impact sample size determinations in clinical studies that use FEV(1) and Dlco as end points.
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Affiliation(s)
- Robert L Jensen
- Pulmonary Laboratory, LDS Hospital and University of Utah, Eighth Ave and C St, Salt Lake City, UT 84143, USA.
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Jensen RL, Teeter JG, England RD, White HJ, Pickering EH, Crapo RO. Instrument Accuracy and Reproducibility in Measurements of Pulmonary Function. Chest 2007; 132:388-95. [PMID: 17573502 DOI: 10.1378/chest.06-1998] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [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: 11/01/2022] Open
Abstract
BACKGROUND The objective of the study was to quantify the accuracy and reproducibility of five commercially available pulmonary function test (PFT) instruments (Collins CPL [Ferraris Respiratory; Louisville, CO]; Morgan Transflow Test PFT System [Morgan Scientific; Haverhill, MA]; SensorMedics Vmax 22D [VIASYS Healthcare; Yorba Linda, CA]; Jaeger USA Masterscreen Diffusion TP [VIASYS Healthcare]; and Medical Graphics Profiler DX System [Medical Graphics Corp; St. Paul, MN]) that are associated with spirometry and the measurement of pulmonary diffusing capacity. METHODS In a multifactor, single-center, repeated-measures, full factorial 90-day study, a pulmonary waveform generator and a single-breath simulator of diffusing capacity of the lung for carbon monoxide (Dlco) were used to perform simulations of FVC and Dlco maneuvers. Accuracy was assessed as the difference between the observed and simulated values. Reproducibility was determined as the coefficient of variation of all measurements made during the study. RESULTS All instruments demonstrated a high degree of accuracy in the measurement of FVC and FEV(1). Overall, the accuracies associated with the measurement of peak flow, forced expiratory flow, mid-expiratory phase, and diffusing capacity were generally lower and more variable among the instruments tested. The coefficients of variation of Dlco measurements over 90 days were higher than those observed for spirometry. CONCLUSIONS This study demonstrates the feasibility of assessing the accuracy and reproducibility of modern PFT instruments using simulation testing. Our results provide an assessment of the component of PFT accuracy and reproducibility that is due to instrumentation alone.
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Affiliation(s)
- Robert L Jensen
- Pulmonary Laboratory, LDS Hospital and University of Utah, Eighth Ave and C St, Salt Lake City, UT 84143, USA.
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England RD, Kullberg MC, Cornette JL, Berzofsky JA. Molecular analysis of a heteroclitic T cell response to the immunodominant epitope of sperm whale myoglobin. Implications for peptide partial agonists. The Journal of Immunology 1995. [DOI: 10.4049/jimmunol.155.9.4295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
We have investigated the molecular basis for binding and Ag presentation of an immunodominant Th cell determinant of sperm whale myoglobin, a prototype amphipathic helical structure in the native protein. A series of peptides with three different substitutions at each position were evaluated for binding to the class II MHC molecule I-Ad and for activation of two T cell clones with distinct fine specificity, to determine the role of each residue. The assignment of MHC binding and TCR binding residues is consistent with a peptide bound as a twisted beta-strand, with 130 degrees twist similar to that of the influenza hemagglutinin peptide crystallized in the groove of HLA-DR1. This twist gives the peptide amphipathicity, with a periodicity similar to an alpha-helix without its being a helix. Two substituted peptides were discovered to be heteroclitic, but by different molecular mechanisms, one involving gain of a favorable residue and one involving loss of an unfavorable one. Complexes of both peptides with I-Ad had enormously higher affinity for the TCR, but peptide affinity for the MHC molecule was not increased, such that the wild-type peptide acted as a partial agonist and inhibited the response to the heteroclitic ones. Moreover, the magnitude of response was elevated in a way that could not be mimicked by the wild-type peptide even at higher concentration. These results suggest a TCR dwell time requirement for optimal signal transduction that may help explain the mechanism of partial agonism.
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Affiliation(s)
- R D England
- Molecular Immunogenetics and Vaccine Research Section, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - M C Kullberg
- Molecular Immunogenetics and Vaccine Research Section, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - J L Cornette
- Molecular Immunogenetics and Vaccine Research Section, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - J A Berzofsky
- Molecular Immunogenetics and Vaccine Research Section, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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14
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England RD, Kullberg MC, Cornette JL, Berzofsky JA. Molecular analysis of a heteroclitic T cell response to the immunodominant epitope of sperm whale myoglobin. Implications for peptide partial agonists. J Immunol 1995; 155:4295-306. [PMID: 7594588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have investigated the molecular basis for binding and Ag presentation of an immunodominant Th cell determinant of sperm whale myoglobin, a prototype amphipathic helical structure in the native protein. A series of peptides with three different substitutions at each position were evaluated for binding to the class II MHC molecule I-Ad and for activation of two T cell clones with distinct fine specificity, to determine the role of each residue. The assignment of MHC binding and TCR binding residues is consistent with a peptide bound as a twisted beta-strand, with 130 degrees twist similar to that of the influenza hemagglutinin peptide crystallized in the groove of HLA-DR1. This twist gives the peptide amphipathicity, with a periodicity similar to an alpha-helix without its being a helix. Two substituted peptides were discovered to be heteroclitic, but by different molecular mechanisms, one involving gain of a favorable residue and one involving loss of an unfavorable one. Complexes of both peptides with I-Ad had enormously higher affinity for the TCR, but peptide affinity for the MHC molecule was not increased, such that the wild-type peptide acted as a partial agonist and inhibited the response to the heteroclitic ones. Moreover, the magnitude of response was elevated in a way that could not be mimicked by the wild-type peptide even at higher concentration. These results suggest a TCR dwell time requirement for optimal signal transduction that may help explain the mechanism of partial agonism.
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Affiliation(s)
- R D England
- Molecular Immunogenetics and Vaccine Research Section, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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15
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Quakyi IA, Currier J, Fell A, Taylor DW, Roberts T, Houghten RA, England RD, Berzofsky JA, Miller LH, Good MF. Analysis of human T cell clones specific for conserved peptide sequences within malaria proteins. Paucity of clones responsive to intact parasites. The Journal of Immunology 1994. [DOI: 10.4049/jimmunol.153.5.2082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
T cells are thought to be of central importance in malaria immunity. Peptides copying malaria protein sequences often stimulate human CD4+ T cells and it was thought that they represented T cell epitopes present in the parasite and may thus have particular relevance to malaria vaccine development. To verify whether synthetic peptides representing highly conserved regions of parasite Ags may contribute to a malaria vaccine, we searched the data bank for conserved regions of Plasmodium falciparum malaria proteins that were not homologous to known self (human) proteins. We synthesized 24 such peptides representing 11 of the cloned and sequenced malaria asexual stage Ags, which were predicted by algorithms to represent T cell epitopes, and 6 peptides not predicted to be T cell epitopes and used these to generate T cell clones from individuals with an extensive previous history of malaria exposure. The T cell clones responded vigorously to many peptides but only a single clone, specific for a peptide within merozoite surface protein-1, 20-39, VTHESYQELVKKLEALEDAV, and not previously defined to be a T cell epitope responded to malaria parasites by proliferation and secretion of IFN-gamma. This epitope was not revealed by studying parasite-induced T cell lines and is thus subdominant. The clone was able to significantly inhibit parasite growth in vitro. The final step in the inhibition of parasite growth appears to be nonspecific because other activated clones (not specific for malaria sequences) can inhibit parasite growth. Our data suggest that few conserved peptides within malaria parasites can be processed from the intact parasite. However, such peptides that can be processed from malaria parasites may be expected to stimulate parasite-specific T cells that could inhibit parasite growth and as such may be lead candidates for a vaccine aimed at inducing cellular immunity to malaria.
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Affiliation(s)
- I A Quakyi
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - J Currier
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - A Fell
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - D W Taylor
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - T Roberts
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - R A Houghten
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - R D England
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - J A Berzofsky
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - L H Miller
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - M F Good
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
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16
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Quakyi IA, Currier J, Fell A, Taylor DW, Roberts T, Houghten RA, England RD, Berzofsky JA, Miller LH, Good MF. Analysis of human T cell clones specific for conserved peptide sequences within malaria proteins. Paucity of clones responsive to intact parasites. J Immunol 1994; 153:2082-92. [PMID: 8051413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
T cells are thought to be of central importance in malaria immunity. Peptides copying malaria protein sequences often stimulate human CD4+ T cells and it was thought that they represented T cell epitopes present in the parasite and may thus have particular relevance to malaria vaccine development. To verify whether synthetic peptides representing highly conserved regions of parasite Ags may contribute to a malaria vaccine, we searched the data bank for conserved regions of Plasmodium falciparum malaria proteins that were not homologous to known self (human) proteins. We synthesized 24 such peptides representing 11 of the cloned and sequenced malaria asexual stage Ags, which were predicted by algorithms to represent T cell epitopes, and 6 peptides not predicted to be T cell epitopes and used these to generate T cell clones from individuals with an extensive previous history of malaria exposure. The T cell clones responded vigorously to many peptides but only a single clone, specific for a peptide within merozoite surface protein-1, 20-39, VTHESYQELVKKLEALEDAV, and not previously defined to be a T cell epitope responded to malaria parasites by proliferation and secretion of IFN-gamma. This epitope was not revealed by studying parasite-induced T cell lines and is thus subdominant. The clone was able to significantly inhibit parasite growth in vitro. The final step in the inhibition of parasite growth appears to be nonspecific because other activated clones (not specific for malaria sequences) can inhibit parasite growth. Our data suggest that few conserved peptides within malaria parasites can be processed from the intact parasite. However, such peptides that can be processed from malaria parasites may be expected to stimulate parasite-specific T cells that could inhibit parasite growth and as such may be lead candidates for a vaccine aimed at inducing cellular immunity to malaria.
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Affiliation(s)
- I A Quakyi
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
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Takeshita T, Kozlowski S, England RD, Brower R, Schneck J, Takahashi H, DeLisi C, Margulies DH, Berzofsky JA. Role of conserved regions of class I MHC molecules in the activation of CD8+ cytotoxic T lymphocytes by peptide and purified cell-free class I molecules. Int Immunol 1993; 5:1129-38. [PMID: 8241055 DOI: 10.1093/intimm/5.9.1129] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
To analyze the molecular interactions involved in CD8+ cytotoxic T lymphocyte (CTL) recognition quantitatively, we developed a cell-free antigen presenting system. Genetically engineered soluble H-2Dd molecules coated on plastic microtiter plates could present HIV envelope peptide to an antigen-specific CTL clone, inducing it to produce IFN-gamma in the absence of accessory cells and their accessory or co-stimulatory molecules. The peptide-MHC complexes were functionally stable for over 24 h. The magnitude of T cell activation was dependent on the concentrations of both class I MHC molecule and the peptide, but was more sensitive to the concentration of the MHC molecule than to that of peptide. This result suggests that one MHC molecule can play more than one role in activating the CTL. One such role is the interaction between CD8 and a conserved region of class I MHC, as suggested by the finding that holding the total MHC concentration constant with an irrelevant class I MHC molecule (H-2Kb engineered to have the same alpha 3 domain as H-2Dd) made the T cell response less sensitive to the change in concentration of the relevant MHC molecule (H-2Dd). The irrelevant class I MHC molecule (H-2Kb), unable to present this peptide by itself, augmented the T cell response at lower concentrations of peptide. These results suggest that the conserved alpha 3 domain of the class I MHC heavy chain as well as polymorphic regions play an important role in T cell activation and that T cell interaction with MHC molecules not presenting peptide can still augment the response.
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Affiliation(s)
- T Takeshita
- Molecular Immunogenetics and Vaccine Research Section, NCI, NIH, Bethesda, MD 20892
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Abstract
The authors review the literature on tactile hallucinations. They examine its occurrence in a schizophrenic patient who had poor response to neuroleptic medication, after several admissions to a psychiatric hospital. The patient responded well to electroconvulsive therapy when it was combined with a small dose of a neuroleptic. Due to prolonged use of neuroleptics he developed tardive dyskinesia that responded only to a large dose of lecithin. They discuss the use of electroconvulsive therapy in schizophrenic patients who have shown little or no response to neuroleptics after prolonged use. The case presented showed better clinical response with smaller doses of antipsychotic medication, when combined with electroconvulsive therapy.
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Affiliation(s)
- A A Salama
- Department of Psychiatry, Southern Illinois University Medical School, Springfield 62702
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Abstract
Carboxymethylation of glucagon and subsequent purification of the hormone has provided a derivative modified by the addition of bulk to the methionine at position 27 without a net charge alteration in the side chain. Unreacted glucagon was removed after methylation of the methionine which provides a positively charged chromatographic handle. The derivative has a half-maximum concentration for binding of 5.3 nM and is a full agonist. These findings along with those provided by methylation of the methionine indicate that a positive charge rather than bulk on the methionine side chain disrupts the binding of hormone to its receptor. The S-carboxymethyl derivative lacks the concentration-dependent aggregation characteristic of glucagon at pH 10.2 as does the S-methyl derivative but increases its helical content in 30% 2-chloroethanol to the same extent as native and S-methyl hormone. Full activity of the S-carboxymethyl methionine27 glucagon does not favor the existence of the globular structure proposed by Korn and Ottensmeyer [(1983) J. Theor. Biol. 105, 403] as the binding species whereas multiple considerations do favor a flexible hormone with nucleation followed by conformational changes for complete binding and activation. Isotopic enrichment using labeled iodoacetate is feasible and can provide more definitive structural information.
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England RD, Jenkins WT, Flanders KC, Gurd RS. Noncooperative receptor interactions of glucagon and eleven analogues: inhibition of adenylate cyclase. Biochemistry 1983; 22:1722-8. [PMID: 6303393 DOI: 10.1021/bi00276a031] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Glucagon and 11 glucagon derivatives were characterized and compared with respect to the cooperativity of their receptor interactions and their ability to elicit a biphasic (activation-inhibition) response from the adenylate cyclase system of rat liver plasma membranes. Slope factors were evaluated from two sets of experimental data, binding to hepatocyte receptors and activation of adenylate cyclase. The results are consistent with noncooperative binding to a single affinity state of the glucagon receptor for all derivatives, irrespective of the modification and the agonist properties of the derivatives. High-dose inhibition of adenylate cyclase activity was observed for native glucagon and all of the derivatives which were examined at high concentrations (greater than 10(-5) M). Partial agonism of some low-affinity glucagon derivatives is not caused by high-dose inhibition. Several mechanisms which might give rise to high-dose inhibition such as receptor cross-linking or multivalent receptor binding are discussed in relationship to the glucagon-receptor interaction. These phenomena indicate that significant differences exist between the glucagon system and the beta-adrenergic system.
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March KL, Maskalick DG, England RD, Friend SH, Gurd FR. Analysis of electrostatic interactions and their relationship to conformation and stability of bovine pancreatic trypsin inhibitor. Biochemistry 1982; 21:5241-51. [PMID: 7171553 DOI: 10.1021/bi00264a020] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The modified Tanford-Kirkwood electrostatic theory has been employed to evaluate pK values for all charge sites in the bovine pancreatic trypsin inhibitor (BPTI). 13C NMR titration data were obtained for all titrating groups except arginine residues in BPTI at nearly constant ionic strength in 0.1 M NaCl, at 41 degrees C. The chemical shifts of 46 resonances were found to be sensitive to pH. The pK values of these titrating resonances compared well with those computed by the modified Tanford-Kirkwood electrostatic theory. A conformational change involving the NH2- and COOH-terminal and nearby residues is shown to be partly electrostatically driven by the formation of a salt bridge between the alpha-amino and alpha-carboxyl groups at mid-pH values. The computed total electrostatic free energy of the molecule is found to be stabilizing at neutral pH despite the substantial net positive charge borne by the protein under such conditions.
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Coolican SA, Jones BN, England RD, Flanders KC, Condit JD, Gurd RS. [25-oxindolylalanine]glucagon and [27-methionine sulfoxide]glucagon: preparation, purification, and characterization. Biochemistry 1982; 21:4974-81. [PMID: 7138842 DOI: 10.1021/bi00263a022] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Flanders KC, Mar DH, Folz RJ, England RD, Coolican SA, Harris DE, Floyd AD, Gurd RS. Semisynthetic derivatives of glucagon: (des-His1)N epsilon-acetimidoglucagon and N alpha-Biotinyl-N epsilon-acetimidoglucagon. Biochemistry 1982; 21:4244-51. [PMID: 7126542 DOI: 10.1021/bi00261a010] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
N epsilon-Acetimidoglucagon to be used for semisynthesis was prepared by reacting glucagon with methyl acetimidate hydrochloride at pH 10.2, favoring acetimidation of the sole epsilon-amino group. N epsilon-Acetimidoglucagon was isolated from the crude acetimidoglucagon mixture by anion-exchange chromatography at pH 9.4, producing a derivative which was identical with native glucagon on isoelectric focusing and which by amino acid analysis had greater than 98% of the lysine blocked. The yield was greater than that obtained when tetrahydrophthalic anhydride was used as a chromatographic handle to remove peptides with unreacted amino groups. N epsilon-Acetimidoglucagon closely resembled native glucagon in its biological activity and binding affinity, eliminating the need for deprotection. Semisynthetic N alpha-biotinyl-N epsilon-acetimidoglucagon, prepared by reacting (N-hydroxysuccinimido)biotin with N epsilon-acetimidoglucagon and purified by cation-exchange chromatography, was homogeneous upon isoelectric focusing (pI = 5.2) and exhibited 1.2% of the binding affinity, 2.4% of the biological potency, and 30% of the maximum activity of the native hormone. Preliminary fluorescence microscopy demonstrated binding of N alpha-biotinyl-N epsilon-acetimidoglucagon to glucagon specific receptors following exposure to fluorescein-labeled avidin. Capping of labeled receptors could be visualized with time. (Des-His1)N epsilon-acetimidoglucagon, prepared via a manual Edman degradation of N epsilon-acetimidoglucagon and isolated by cation-exchange chromatography, was homogeneous upon isoelectric focusing (pI = 5.2). The second residue, serine, has also been removed. Semisynthetic coupling of alternative residues to such derivatives will provide insight into the role of the amino-terminal residues in mediating the biological actions of the hormone.
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England RD, Jones BN, Flanders KC, Coolican SA, Rothgeb TM, Gurd RS. Glucagon carboxyl-terminal derivatives: preparation, purification, and characterization. Biochemistry 1982; 21:940-50. [PMID: 7074063 DOI: 10.1021/bi00534a020] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Chemical and enzymatic methods have been used to prepare the following series of seven glucagon derivatives modified in the carboxyl-terminal region important for hormone-receptor binding: [des-Asn28,Thr29](homoserine lactone27)glucagon, [des-Asn28,Thr29](homoserine27)glucagon, (S-methyl-Met27)glucagon, [des-Thr29](S-methyl-Met27)-glucagon, [des-Thr29]glucagon,[des-Asn28,Thr29](S-methyl-Met27)glucagon, and [des-Asn28,Thr29]glucagon. The derivatives were isolated in high yield, extensively purified, and chemically characterized. All were found to be full agonists of native glucagon. Binding affinity was evaluated by displacement of mono[125I]iodoglucagon prepared by new methods. Binding and biological activities closely correlated, indicating that most modifications affected the relative binding affinity and relative biological potency of glucagon to a comparable extent. Circular dichroism measured in dilute acid solution resembled that of native glucagon except for [des-Asn28,Thr29]glucagon which displayed increased alpha helicity (25%). All derivatives formed helical structures in 2-chloro-ethanol, although the amount of helicity induced was not closely correlated with biological activity. Binding and biological activities were not affected by removal of Thr-29, though both were reduced 20-fold when Asn-28 was also removed, irrespective of whether homoserine or native methionine remained at the carboxyl terminus. Lactone formation was associated with a further 5-fold reduction in binding affinity but not in activity. Methylation of Met-27 had essentially the same effect as removing the two carboxyl-terminal residues, although the combined effect of both modifications was greater than 100-fold reduction in binding and activity. These findings provide additional insight concerning glucagon structure-function relationships.
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Jones BN, Rothgeb TM, England RD, Gurd FR. Complete amino acid sequence of the myoglobin from the Pacific sei whale, Balaenoptera borealis. Biochim Biophys Acta 1979; 577:464-74. [PMID: 454658 DOI: 10.1016/0005-2795(79)90050-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The complete amino acid sequence of the major component myoglobin from Pacific sei whale, Balaenoptera borealis, was determined by specific cleavage of the protein to obtain large peptides which are readily degraded by the automatic sequencer. The acetimidated apomyoglobin was selectively cleaved at its two methionyl residues with cyanogen bromide and at its three arginyl residues by trypsin. From the sequence analysis of four of these peptides and the apomyoglobin, over 75% of the covalent structure of the protein was obtained. The remainder of the primary structure was determined by the sequence analysis of peptides that resulted from further digestion of the amino-terminal and central cyanogen bromide fragments. The amino-terminal fragment was specifically cleaved at its two tryptophanyl residues with N-chlorosuccinimide and the central cyanogen bromide fragment was cleaved at its glutamyl residues with staphylococcal protease and at its single tyrosyl residue with N-bromosuccinimide. The primary structure of this myoglobin proved identical with that from the gray whale but differs from that of the finback whale at four positions, from that of the minke whale at three positions and from the myoglobin of the humpback whale at one position. The above sequence identities and differences reflect the close taxonomic relationship of these five species of Cetacea.
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Rothgeb TM, England RD, Jones BN, Gurd RS. Physical characterization of S-methylglucagon and quantitation of carbamino adduct formation. Biochemistry 1978; 17:4564-71. [PMID: 718858 DOI: 10.1021/bi00614a031] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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