J K Powrie

Guy's and St Thomas' NHS Foundation Trust, Londinium, England, United Kingdom

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Publications (30)115.62 Total impact


  • No preview · Article · Mar 2014
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    ABSTRACT: There are no consensus guidelines on the optimum long-term care of patients with primary adrenal failure. Published data suggest increased morbidity and mortality in patients treated with current therapy. Investigations of bone mineral density (BMD) in adults with adrenal failure have reported conflicting results. The objectives of this study were to determine the prevalence of auto-immune and other co-morbidities, describe the treatment regimens and to assess the BMD of adults with auto-immune Addison's disease (AAD). A retrospective, cohort study of adults with primary adrenal failure was used. Electronic and paper records were used to collect demographic, biochemical, BMD data and details of other co-morbidities. 48 patients (35% male; 65% female; 50 ± 16, years, mean ± SD) with primary adrenal failure were identified. There was high prevalence of other auto-immune co-morbidities (hypothyroidism 58%, vitamin B(12) deficiency 29%, type 1 diabetes 10%). The presence of cardiovascular risk factors including dyslipidaemia (65% had total cholesterol >5 mmol/l) and excess weight (65% had a BMI >25 kg/m(2)) were high. Using WHO criteria, 17.9 and 53.5% of patients had spinal osteoporosis and osteopenia, respectively, at the spine. This did not relate to the duration or dose of glucocorticoid replacement. Our data shows a high prevalence of both auto-immune and non-autoimmune co-morbidities in patients with AAD. In addition to common auto-immune diseases, patients should be screened for other cardiovascular risk factors. Further studies are needed to assess the cause of the observed increased prevalence of reduced BMD at the lumbar spine. There is a need for internationally agreed long-term management guidelines.
    No preview · Article · Aug 2010 · Endocrine
  • M S B Huda · N B Athauda · M M Teh · P V Carroll · J K Powrie
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    ABSTRACT: Withdrawal of dopamine agonist (DA) therapy in the management of microprolactinoma is common practice, but it is unclear which patients are likely to attain long-term remission. To identify predictive factors for long-term remission. Prospective cohort study. Forty subjects (39 female, aged 24-60 years) with microprolactinoma; all had been normoprolactinaemic on DA therapy for at least 2 years [mean duration of therapy 9 years (range 2-27)]. A pituitary magnetic resonance imaging (MRI) was performed on 36 (90%) subjects before DA withdrawal. Relapse was defined as prolactin greater than 480 mIU/l (22.8 microg/l) on two occasions. Nine out of 40 (22.5%) subjects were normoprolactinaemic 12 months after DA withdrawal. Amongst the relapse group, 24 of 31 subjects (79.4%) had already relapsed at 3 months. Normalization of MRI prior to DA withdrawal (P = 0.0006) and longer duration of DA treatment (P = 0.032) were significant predictors of remission. Age, pre-treatment prolactin, nadir prolactin, previous failure of DA withdrawal, pregnancy, dose and type of DA were not significant predictors of remission. The nine patients who were in remission at 12 months were then followed up for 58.0 +/- 5.8 months; all remained in remission. As many as 22.5% of subjects with microprolactinoma remained normoprolactinaemic 12 months after DA withdrawal and these subjects stayed in remission for up to 5 years. Significant predictive factors were normalization of MRI prior to discontinuation, and duration of DA treatment. Our findings support intermittent DA withdrawal after a period of normoprolactinaemia, particularly where MRI appearances have normalized.
    No preview · Article · Jul 2009 · Clinical Endocrinology
  • L Leelarathna · J.K. Powrie · P.V. Carroll
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    ABSTRACT: Thomas Addison was first to describe adrenocortical failure in 1855. Despite advances in the treatment of this condition, the diagnosis is still often delayed and sometimes missed with potentially fatal consequences. From the same institution where Thomas Addison performed his original autopsy studies, we present four recent cases highlighting the wide clinical spectrum and discuss how modern biochemical and immunological tests could be utilized in early diagnosis and aetiological classification.
    No preview · Article · Jun 2009 · QJM: monthly journal of the Association of Physicians
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    ABSTRACT: To develop a test for GH abuse in sport. A double blind placebo controlled study of one month's GH administration to 102 healthy non-competing but trained subjects. Blood levels of nine markers of GH action were measured throughout the study and for 56 days after cessation of GH administration. Blood samples were also taken from 813 elite athletes both in and out of competition. GH caused a significant change in the nine measured blood markers. Men were more sensitive to the effects of GH than women. IGF-I and N-terminal extension peptide of procollagen type III were selected to construct formulae which gave optimal discrimination between the GH and placebo groups. Adjustments were made to account for the fall in IGF-I and P-III-P with age and the altered distribution seen in elite athletes. Using a cut-off specificity of 1:10,000 these formulae would allow the detection of up to 86% of men and 60% of women abusing GH at the doses used in this study. We report a methodology that will allow the detection of GH abuse. This will provide the basis of a robust and enforceable test identifying those who are already cheating and provide a deterrent to those who may be tempted to do so.
    Full-text · Article · Jul 2007 · Growth Hormone & IGF Research
  • J Kumar · M Spring · P V Carroll · S F Barrington · J K Powrie
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    ABSTRACT: Neuroendocrine tumours (NET) are a rare cause of Cushing's syndrome. These tumours can be very small and therefore difficult to identify. Current localization techniques include CT, MRI and radioisotope scanning, but in a proportion of cases the NET remains occult. Positron emission tomography (PET) scanning, is a relatively new imaging modality that is increasingly used to detect and monitor lesions with high metabolic activity. We report on the use of PET scanning in the evaluation of the ectopic ACTH syndrome. Three patients with ectopic ACTH-dependent Cushing's syndrome with varying difficulty in NET localization are included in the report. Positron emission tomography scanning using 18flurodeoxyglucose (FDG) identifies tissue with high metabolic activity. 18FDG-PET scanning was used in each of these patients and the imaging is presented along with biochemical data. In each case the NET was easily identified using 18FDG-PET, aiding clinical decision making and therapeutic outcome. A cure was identified by clinical resolution of symptoms and undetectable ACTH levels postsurgery. 18FDG-PET assisted in localizing small metabolically active NETs, suggesting this imaging modality may have a useful role in identifying NET causing Cushing's syndrome as a result of ectopic ACTH production.
    No preview · Article · May 2006 · Clinical Endocrinology
  • S Mehmet · J K Powrie

    No preview · Article · Feb 2003 · Clinical Endocrinology

  • No preview · Article · May 2002 · Medicine & Science in Sports & Exercise
  • M J Krimholtz · S Thomas · J Bingham · J K Powrie
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    ABSTRACT: Lymphocytic hypophysitis is an uncommon condition that typically occurs during the last trimester of pregnancy or in the postpartum period. Presentation is of an anterior pituitary mass with varying degrees of pituitary dysfunction. We present a case in which there was dramatic resolution of the pituitary lesion on sequential MRI scanning. Despite this apparent resolution, however, the patient continues to have significant pituitary dysfunction.
    No preview · Article · Jul 2001 · International Journal of Clinical Practice
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    Preview · Article · Jan 2001 · Diabetologia Kliniczna
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    R.I.G. Holt · J K Powrie · P H Sönksen

    Full-text · Article · Jan 2001 · Journal of the Royal Society of Medicine
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    S Coster · M C Gulliford · P T Seed · J K Powrie · R Swaminathan
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    ABSTRACT: Self-monitoring of blood or urine glucose is widely used by subjects with Type 2 diabetes mellitus. This study evaluated the effectiveness of the technique at improving blood glucose control through a systematic review and meta-analysis. Randomized controlled trials were identified that compared the effects of blood or urine glucose monitoring with no self-monitoring, or blood glucose self-monitoring with urine glucose self-monitoring, on glycated haemoglobin as primary outcome in Type 2 diabetes. Eight reports were identified. These were rated for quality and data were abstracted. The mean (SD) quality score was 15.0 (1.69) on a scale ranging from 0 to 28. No study had sufficient power to detect differences in glycated haemoglobin (GHb) of less than 0.5%. One study was excluded because it was a cluster randomized trial of a complex intervention and one because fructosamine was used as the outcome measure. A meta-analysis was performed using data from four studies that compared blood or urine monitoring with no regular monitoring. The estimated reduction in GHb from monitoring was -0.25% (95% confidence interval -0.61 to 0.10%). Three studies that compared blood glucose monitoring with urine glucose monitoring were also combined. The estimated reduction in GHb from monitoring blood glucose rather than urine glucose was -0.03% (-0.52 to 0.47%). The results do not provide evidence for clinical effectiveness of an item of care with appreciable costs. Further work is needed to evaluate self-monitoring so that resources for diabetes care can be used more efficiently.
    Full-text · Article · Dec 2000 · Diabetic Medicine
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    ABSTRACT: To test whether a thyroxyl-insulin analog with restricted access to receptor sites in peripheral tissues displays relative hepatoselectivity in humans. Five normal human subjects received a subcutaneous bolus injection of either N(alphaBl) L-thyroxyl-insulin (Bl-T4-Ins) or NPH insulin in random order. Insulin kinetics, relative effects on hepatic glucose production, and peripheral glucose uptake were studied using euglycemic clamp and stable isotope [D-6,6-(2)H2]glucose) dilution techniques. Blood samples were taken for the determination of total immunoreactive insulin/analog concentrations and for liquid chromatography to assess the protein binding of the analog in the circulation. After subcutaneous administration, Bl-T4-Ins was well tolerated and rapidly absorbed. The analog had a long serum half-life and was highly protein bound (approximately 86%). Its duration of action, as judged by the duration of infusion of exogenous glucose to maintain euglycemia, was similar to that of NPH insulin. The effect of the analogs on hepatic glucose production was similar to that of NPH insulin, indicating equivalent hepatic potency. The analog demonstrated less effect on peripheral glucose uptake than NPH insulin (P = 0.025), had no effect on metabolic clearance rate of glucose, and exhibited a reduced capacity to inhibit lipolysis (P < 0.05). When injected subcutaneously into normal human subjects, Bl-T4-Ins is well tolerated, quickly absorbed, and highly protein bound, resulting in a long plasma halflife. This analog appears to have a hepatoselective action, and, therefore, has the potential to provide more physiological insulin action than the insulin preparations currently used.
    Full-text · Article · Aug 2000 · Diabetes Care
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    S Coster · M C Gulliford · P T Seed · J K Powrie · R Swaminathan

    Full-text · Article · Feb 2000 · Health technology assessment (Winchester, England)
  • J K Powrie · S Thomas

    No preview · Article · Oct 1999 · International Journal of Clinical Practice
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    R Hovorka · E Koukkou · D Southerden · J K Powrie · MA Young
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    ABSTRACT: The accuracy of calculations of pre-hepatic insulin secretion were investigated, to provide independent validation of a population model of C-peptide kinetics. The effects of sampling frequency were also assessed. Five normal subjects (aged 28 to 43 years; BMI (kg/m2) 20.5 to 24.5) and five subjects with non-insulin-dependent diabetes mellitus (NIDDM) treated by diet alone (aged 34 to 57 years; BMI 22.6 to 25.6) were given a variable intravenous infusion of biosynthetic human C-peptide (BHCP) (t=-60 to 240 min) mimicking meal stimulated C-peptide secretion, with short-term oscillations (peak approximately every 12 min) superimposed on the infusion profile. Plasma C-peptide was measured every 5 min (t=0 to 240 min). The BHCP infusion was reconstructed from C-peptide measurements using a population model of C-peptide kinetics and a deconvolution method. Bias, defined as the percentage difference between the total amount of calculated BHCP and the total amount of infused BHCP (t=0 to 240 min), indicated that overall C-peptide secretion can be measured with 14% [95% confidence interval (CI) -11 to 39%] and 21% (95% CI -3 to 45%) accuracy in normal subjects and subjects with NIDDM respectively. Accuracy was not reduced by reducing the sampling frequency to every 30 min. The root mean square error, measuring the average deviation between the infused and normalised calculated BHCP profiles, was also independent of the sampling frequency [mean (95% CI) 0.9 (0.3 to 1.6) pmol/kg per min in normal subjects; 1.0 (0.9 to 1.1) pmol/kg per min in subjects with NIDDM]. Deconvolution employing a population model of C-peptide kinetics can be used to estimate postprandial total C-peptide secretion with biases of 14% and 22% respectively in normal subjects and subjects with NIDDM. Plasma C-peptide samples need only be drawn every 30 minutes.
    Full-text · Article · Jun 1998 · Diabetologia
  • S F O'Brien · J K Powrie · G F Watts

    No preview · Article · Apr 1997 · Annals of Clinical Biochemistry
  • G.F. Watts · J.K. Powrie · S.F. O'Brien · K.M. Shaw
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    ABSTRACT: The purpose of the study was to examine the contribution of alterations in lipoprotein metabolism to the progression of very-low-level albuminuria in insulin-dependent diabetes mellitus (IDDM). We measured serum concentrations of lipids, lipoproteins, and apolipoproteins in 53 normoalbuminuric diabetic patients without overt hypertension, whom we restudied after 10 years. Albuminuria was measured as the urinary albumin to creatinine ratio (UA/UC) in repeated early-morning samples. Over 10 years, UA/UC increased significantly (P < .001), and five patients (9.4%) progressed to microalbuminuria. The increase in albuminuria was significantly and positively related to the baseline serum concentrations of total cholesterol (P < .05), low-density lipoprotein (LDL) cholesterol (P = .05), non-high-density lipoprotein (HDL) cholesterol (P < .05), and apolipoprotein (apo) B (P < .001), but no significant associations were found with triglycerides, HDL cholesterol, apo A-1, or lipoprotein(a) [Lp(a)]. The relative risk of developing microalbuminuria for a serum apo B concentration more than 1.1 g/L was 3.8 (95% confidence interval [CI], 1.9 to 7.7). In multiple linear regression analysis, serum apo B (P < .05) and glycated hemoglobin ([HbA] P < .05) at baseline were significant independent predictors of the increase in albuminuria, with no significant associations found for sex, smoking, duration of diabetes, mean arterial blood pressure (BP), or family history of cardiovascular disease and hypertension; the regression model predicted 42% of the variation in UA/UC at 10 years. The findings suggest that an abnormality in the metabolism of apo B may be independently associated with progression of very-low-level albuminuria and possibly with the development of early nephropathy in IDDM patients.
    No preview · Article · Sep 1996 · Metabolism
  • E R E Denton · J K Powrie · A B Ayers · P H Sonksen
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    ABSTRACT: In four patients presenting in childhood with varying degrees of hypopituitarism, magnetic resonance imaging (MRI) showed a reduction in size of the normal pituitary fossa contents and an absent or very narrow stalk. A high signal intensity, enhancing area at the base of the stalk, having the appearances and signal characteristics of the posterior pituitary, was seen in each case. We discuss the case histories and MR findings in our patients and review the relevant literature.
    No preview · Article · Jun 1996 · British Journal of Radiology
  • J.K. Powrie · G.F. Watts · M.A. Crook · J.N. Ingham · N.A. Taub · K.M. Shaw
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    ABSTRACT: Elevated serum sialic acid (SSA) predicts cardiovascular disease in the non-diabetic population and is also associated with the presence of microalbuminuria and clinical proteinuria in patients with insulin-dependent diabetes (IDDM). We have studied 121 patients with IDDM of long duration (mean duration 25.2 years) to investigate the relationship of SSA concentrations to the presence of retinopathy, nephropathy, and neuropathy. SSA levels were elevated in patients with retinopathy (0.578 +/- 0.161 gl-1, n = 98) when compared with those without retinopathy (0.468 +/- 0.145 gl-1, n = 23, p = 0.002). Patients with nephropathy (urinary albumin:creatinine ratio of > 3 mg mmol-1 in all of three early morning specimens of urine) also had raised SSA levels (0.625 +/- 0.169 gl-1, n = 30) compared with those without nephropathy (0.533 +/- 0.160 gl-1, n = 91, p = 0.006). There was a significant correlation of SSA with urinary albumin:creatinine ratio (correlation coefficient 0.33, p < 0.001). SSA levels were not related to the presence or absence of neuropathy (0.567 +/- 0.181 gl-1, n = 28, vs 0.533 +/- 0.160 gl-1, n = 93, p = 0.92, respectively). In conclusion, retinopathy and nephropathy but not neuropathy are associated with increased SSA levels in patients with IDDM. The significance of this is not yet clear but it is possible that sialic acid is involved in the pathophysiology of microvascular disease in IDDM.
    No preview · Article · Mar 1996 · Diabetic Medicine

Publication Stats

895 Citations
115.62 Total Impact Points

Institutions

  • 2006-2010
    • Guy's and St Thomas' NHS Foundation Trust
      • Department of Diabetes and Endocrinology
      Londinium, England, United Kingdom
  • 2000
    • King's College London
      Londinium, England, United Kingdom
  • 1996
    • Royal Perth Hospital
      Perth City, Western Australia, Australia