Short-term stability in refractive status despite large fluctuations in glucose levels in diabetes mellitus type 1 and 2

Purpose: This work investigates how short-term changes in blood glucose concentration affect the refractive components of the diabetic eye in patients with long-term Type 1 and Type 2 diabetes. Methods: Blood glucose concentration, refractive error components (mean spherical equivalent MSE, J0, J45), central corneal thickness (CCT), anterior chamber depth (ACD), crystalline lens thickness (LT), axial length (AL) and ocular aberrations were monitored at two-hourly intervals over a 12-hour period in: 20 T1DM patients (mean age ± SD) 38±14 years, baseline HbA1c 8.6±1.9%; 21 T2DM patients (mean age ± SD) 56±11 years, HbA1c 7.5±1.8%; and in 20 control subjects (mean age ± SD) 49±23 years, HbA1c 5.5±0.5%. The refractive and biometric results were compared with the corresponding changes in blood glucose concentration. Results: Blood glucose concentration at different times was found to vary significantly within (p0.05). Minor changes of marginal statistical or optical significance were observed in some biometric parameters. Similarly there were some marginally significant differences between the baseline biometric parameters of well-controlled and poorly-controlled diabetic subjects. Conclusion: This work suggests that normal, short-term fluctuations (of up to about 6 mM/l on a timescale of a few hours) in the blood glucose levels of diabetics are not usually associated with acute changes in refractive error or ocular wavefront aberrations. It is therefore possible that factors other than refractive error fluctuations are sometimes responsible for the transient visual problems often reported by diabetic patients

Diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is the most common acute hyperglycaemic emergency in people with diabetes mellitus. A diagnosis of DKA is confirmed when all of the three criteria are present — ‘D’, either elevated blood glucose levels or a family history of diabetes mellitus; ‘K’, the presence of high urinary or blood ketoacids; and ‘A’, a high anion gap metabolic acidosis. Early diagnosis and management are paramount to improve patient outcomes. The mainstays of treatment include restoration of circulating volume, insulin therapy, electrolyte replacement and treatment of any underlying precipitating event. Without optimal treatment, DKA remains a condition with appreciable, although largely preventable, morbidity and mortality. In this Primer, we discuss the epidemiology, pathogenesis, risk factors and diagnosis of DKA and provide practical recommendations for the management of DKA in adults and children

In-vivo dosimetry for gynaecological brachytherapy: Physical and clinical considerations

Introduction: The study aimed to estimate the dosimetric uncertainty using diodes (PTW/Germany) for a high-dose rate Iridum-192 source under clinical conditions. Finally, the role of in-vivo dosimetry for cervix cancer patients was evaluated. Material and methods: First, diode calibration and factors influencing diode response were investigated and phantom studies compared doses measured and computed by the treatment planning system. Based on that, the uncertainty for diode measurements was estimated to be 7% (1 sigma). Secondly, 55 applications of patients with cervix carcinoma were evaluated. Doses in rectum and bladder were measured and compared to the computed doses and differences were calculated. If the differences exceeded 10% the corresponding shift in probe position was evaluated. Additionally, the in-vivo dosimetry data were compared to doses at the ICRU 38 [ICRU Report No. 38, dose and volume specification for reporting intracavitary therapy in gynaecology. In: Chassagne D, Dutreix A, Almond P, Burgers J, Busch M, Joslin C editors. International commissioning on radiation units and measurements. Bethesda: 1985.] reference points for rectum and bladder. Results: In patients, in-vivo dosimetry resulted in differences between calculated and measured doses ranging from -31 to +90% (mean 11%) for the rectum and from -27 to +26% (mean 4%) for the bladder. Shifts in probe position of 2.5 mm for the rectal probe and 3.5 mm for the bladder probe caused dose differences exceeding 10%. The dose at the ICRU rectum reference point was underestimated by the calculated doses at probe position ranging from -61 to 156% (mean 29%). The dose to the ICRU bladder reference point was underestimated by the calculated dose ranging from 12 to 162% (mean 58%). Conclusion: The study shows that diode accuracy and reproducibility is sufficient for clinical applications. For accurate in-vivo dosimetry geometric conditions are of outmost importance. It is recommended that in-vivo dosimetry should be performed in addition to computation. (c) 2005 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 77 (2005) 310-317

Serum insulin concentrations in horses with equine Cushing's syndrome: response to a cortisol inhibitor and prognostic value

Reasons for performing study: Serum insulin concentration and its use as a prognostic indicator in horses with equine Cushing's syndrome (ECS) have been poorly documented. Objectives: To examine daily insulin variations in horses with ECS and the effect of treatment using trilostane, a competitive inhibitor of 3β-hydroxysteroid dehydrogenase. Further, we aimed to examine the relationship between baseline serum insulin concentration and survival in horses with ECS. Methods: Basal serum insulin concentrations were measured in 20 confirmed ECS cases by taking blood at regular 4 h intervals for 24 h (1200, 1600, 2000, 2400, 0400 and 0800 h) before treatment (Day 0) and 10 days, and 30 days and 1-2 years after the onset of trilostane therapy. The temporal pattern of insulin was analysed using a linear mixed model approach, and the prognostic value of measurements on Day 0 assessed using receiver-operating characteristic analysis. Results: Horses with ECS showed a diurnal pattern of serum insulin concentration, highest value at 1200 h, and this pattern was not altered by treatment with trilostane. Furthermore, despite a mild increase of serum insulin concentrations after 10 days of trilostane therapy, insulin concentration was unaffected in the long term. Low serum insulin concentrations at the beginning of the trial were significantly associated with improved survival to 1-2 years. The 1200 h sampling before treatment had the highest prognostic value for prediction of survival with a sensitivity and specificity of at least 90% for serum insulin at 188 μu/ml to predict survival and nonsurvival, respectively. Conclusions and potential relevance: Insulin is a useful prognostic indicator for ECS, but potentially large variations can occur throughout a 24 h period, indicating a single sample may not be representative. Serum insulin concentration did not increase over 1-2 years in horses receiving trilostane therapy