Uzma Khan

Use of a Novel Fluorescent Glucose Sensor in Volunteer Subjects with Type 1 Diabetes Mellitus

Background: Stress hyperglycemia in the critically ill has been found to be associated with increased morbidity and mortality. Studies have found significant improvements in morbidity and mortality in postsurgical patients whose glucose levels were closely maintained in the euglycemic range. However, subsequent studies, in particular the Normoglycemia in Intensive Care Evaluation and Survival Using Glucose Algorithm Regulation (NICE-SUGAR) study, found no improvement in subjects with tight glycemic control. In addition to differences in protocol design, patients in the tight glycemic control arm of the NICE-SUGAR study experienced high rates of hypoglycemia compared with other studies. One interpretation of the NICE-SUGAR study results is that it is difficult to achieve normal glycemia in critically ill patients with existing glucose monitoring technology. The purpose of the study reported here was to evaluate the safety and performance of a continuous intravascular glucose sensor that could be used in the future in critically ill patients. Methods: A first-generation prototype of an intravascular continuous glucose sensor was evaluated in 29 volunteer subjects with type 1 diabetes mellitus. The sensor operates on the principle of quenched fluorescence. The fluorescent emission from the sensor chemistry is nonlinear, resulting in improved accuracy in the hypoglycemic range. The duration of each study was 8 hours. Sensor output was compared with temporally correlated reference measurements made from venous samples on a laboratory glucose analyzer. Results: Data were obtained from 18 of the 29 subjects in the study. Data were analyzed retrospectively using a factory calibration plus a one-point in vivo calibration. The mean absolute relative difference was 7.97%, and 95.1% of all the points were in zone A of the Clarke error grid. Conclusions: This pilot study was the first use in human subjects of a prototype of the GluCath Intravascular Continuous Glucose Monitoring System (GluCath System). The GluCath System is based on a novel fluorescent sensor chemistry. The study found the GluCath System had a high level of accuracy as compared with a laboratory reference analyzer.

An Analysis of Diabetes Mobile Applications Features Compared to AADE7™: Addressing Self-Management Behaviors in People With Diabetes:

Background: Diabetes self-management (DSM) applications (apps) have been designed to improve knowledge of diabetes and self-management behaviors. However, few studies have systematically examined if diabetes apps followed the American Association of Diabetes Educators (AADE) Self-Care Behaviors™ guidelines. The purpose of this study was to compare the features of current DSM apps to the AADE7™ guidelines. Methods: In two major app stores (iTunes and Google Play), we used three search terms “diabetes,” “blood sugar,” and “glucose” to capture a wide range of diabetes apps. Apps were excluded based on five exclusion criteria. A multidisciplinary team analyzed and classified the features of each app based on the AADE7™. We conducted interviews with six diabetes physicians and educators for their opinions on the distribution of the features of DSM apps. Results: Out of 1050 apps retrieved, 173 apps were identified as eligible during November 2015 and 137 apps during December 2017. We found an unbalanced DSM app development trend based on AADE7™ guidelines. Many apps were designed to support the behaviors of Healthy Eating (77%), Monitoring (76%), Taking Medication (58%), and Being Active (45%). On the other hand, few apps explored the behaviors of Problem Solving (31%), Healthy Coping (10%), and Reducing Risks (5%). From interviews, we identified the main reasons why only a few apps support the features related to Problem Solving, Healthy Coping, and Reducing Risks. Conclusions: Future diabetes apps should attempt to incorporate features under evidence-based guidelines such as AADE7™ to better support the self-management behavior changes of people with diabetes.

Evaluation of accuracy dependence of Raman spectroscopic models on the ratio of calibration and validation points for non-invasive glucose sensing

AbstractOptical monitoring of blood glucose levels for non-invasive diagnosis is a growing area of research. Recent efforts in this direction have been inclined towards reducing the requirement of calibration framework. Here, we are presenting a systematic investigation on the influence of variation in the ratio of calibration and validation points on the prospective predictive accuracy of spectral models. A fiber-optic probe coupled Raman system has been employed for transcutaneous measurements. Limit of agreement analysis between serum and partial least square regression predicted spectroscopic glucose values has been performed for accurate comparison. Findings are suggestive of strong predictive accuracy of spectroscopic models without requiring substantive calibration measurements. Graphical abstract

Evaluation of Functionality and Usability on Diabetes Mobile Applications: A Systematic Literature Review

Objective: To systematically review the studies related to the functionality and usability evaluation of diabetes mobile apps. Method: We searched three electronic databases: PubMed, Scopus, and Cochrane. The search terms used were “mobile app”, “mobile application”, “diabetes”, and “evaluation”. We limited the articles to those that were written in English and published from January 1, 2006 to October 4, 2016. Results: There were seven articles focused on type 1 diabetes, two articles focused on type 2 diabetes, two articles focused on both type 1 and type 2 diabetes, nine articles focused on diabetes that authors did not state specific type. With regard to types of evaluation, only one study reported solely on functionality, seven studies reported usability, and twelve studies reported both functionality and usability. The methods used for evaluations included survey, interview, laboratory testing, user testing, questionnaire, expert evaluation, and heuristic evaluation. Conclusion: Future studies should consider the standard evaluation methods for evaluate functionality and usability of diabetes self-management (DSM) apps.

Surgical Cure of Hypertension in a Patient With MEN 2A Syndrome and Mixed Dopamine, Metanephrine Pheochromocytoma

CASE HISTORY A 63-year-old woman with a long history of hypertension presented in 2006 with hypertensive urgency associated with palpitations and headache. A 24-hour urine collection had markedly elevated total urine metanephrines (Table). A computed tomographic (CT) scan with contrast revealed an irregular, 3.6 cm, high attenuation, enhancing left adrenal mass with delayed washout (Figure 1). Laparoscopic left adrenalectomy in 2006 and pathological analysis confirmed a pheochromocytoma (PCC) with a PCC of the adrenal gland scaled score (PASS) of 3 based on adipose tissue and capsular invasion. Follow-up 24-hour urine collections showed normal urine catecholamines. In 2009 the patient was evaluated for impaired glucose tolerance and persistent hypertension despite triple drug therapy. She noted episodes of lightheadedness upon standing associated with palpitations and sweating, as well as weight loss. She then revealed a family history of thyroid cancer in her father and grandmother (Figure 2). Due to suspicion of recurrent or asynchronous second primary PCC and multiple endocrine neoplasia type 2 (MEN 2) syndrome, a 24-hour urine was collected and showed mild elevation of catecholamines, including dopamine, in both plasma and urine. Genetic testing revealed a RET proto-oncogene mutation at the Cys634Arg site. A calcitonin level was measured and found to be elevated. A CT scan of the abdomen showed postoperative changes on the left side, and an enhancing mild nodularity in the right adrenal gland. An I131 iodine meta-iodobenzylguanidine (MIBG) scan revealed mild uptake, superior and medial to the right kidney. Ultrasound and CT scan of the neck revealed a heterogeneous and multinodular thyroid with calcification (Figure 3). Following a-blockade with phenoxybenzamine, she underwent a laparoscopic right adrenalectomy. Pathology confirmed a 2 cm right adrenal PCC (Figure 4) with a PASS of 6 due to a pattern of over 10% of the tumor volume, extension into periadrenal fat, profound nuclear pleomorphism, and nuclear hyperchromasia (Figure 5). A total thyroidectomy specimen yielded a calcitonin positive medullary carcinoma without lymph node involvement. Currently, the patient is no longer taking blood pressure medications and a follow-up 24-hour catecholamine collection and serum calcitonin were normal. Family screening revealed a RET proto oncogene mutation in her brother and two of her nephews (Figure 2). From the Division of Endocrinology, Diabetes and Metabolism, University of Missouri, Harry S Truman Veteran Hospital, Columbia, MO Address for correspondence: James R. Sowers, MD, Division of Endocrinology, Diabetes and Metabolism, University of Missouri, Harry S. Truman Veteran Hospital, Columbia, MO E-mail: sowersj@health.missouri.edu