Ridder T.D.,TruTouch Technologies |
Hull E.L.,VeraLight |
Ver Steeg B.J.,TruTouch Technologies |
Laaksonen B.D.,TruTouch Technologies
Journal of Biomedical Optics | Year: 2011
Previous works investigated a spectroscopic technique that offered a promising alternative to blood and breath assays for determining in vivo alcohol concentration. Although these prior works measured the dorsal forearm, we report the results of a 26-subject clinical study designed to evaluate the spectroscopic technique at a finger measurement site through comparison to contemporaneous forearm spectroscopic, venous blood, and breath measurements. Through both Monte Carlo simulation and experimental data, it is shown that tissue optical probe design has a substantial impact on the effective path-length of photons through the skin and the signal-to-noise ratio of the spectroscopic measurements. Comparison of the breath, blood, and tissue assays demonstrated significant differences in alcohol concentration that are attributable to both assay accuracy and alcohol pharmacokinetics. Similar to past works, a first order kinetic model is used to estimate the fraction of concentration variance explained by alcohol pharmacokinetics (72.6-86.7%). A significant outcome of this work was significantly improved pharmacokinetic agreement with breath (arterial) alcohol of the finger measurement (meankArt-Fin = 0.111 min- 1) relative to the forearm measurement (mean k Art- For = 0.019 min -1) that is likely due to the increased blood perfusion of the finger. © 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).
Maynard J.D.,University of Pittsburgh |
Neurology | Year: 2015
Although microvascular complications are common in type 1 diabetes mellitus (T1DM), few studies have quantified the severity, risk factors, and implications of cerebral microvascular damage in these patients. As life expectancy in patients with T1DM increases, patients are exposed to age-and disease-related factors that may contribute to cerebral microvascular disease. Methods: Severity and volume of white matter hyperintensities (WMH) and infarcts were quantified in 97 middle-aged patients with childhood-onset T1DM (mean age and duration: 50 and 41 years, respectively) and 81 non-T1DM adults (mean age: 48 years), concurrent with cognitive and health-related measures. Results: Compared with non-T1DM participants, patients had more severe WMH (Fazekas scores 2 and 3 compared with Fazekas score 1, p < 0.0001) and slower information processing (digit symbol substitution, number correct: 65.7 ± 10.9 and 54.9 ± 13.6; pegboard, seconds: 66.0 ± 9.9 and 88.5 ± 34.2; both p < 0.0001) independent of age, education, or other factors. WMH were associated with slower information processing; adjusting for WMH attenuated the group differences in processing speed (13% for digit symbol, 11% for pegboard, both p ≤ 0.05). Among patients, prevalent neuropathies and smoking tripled the odds of high WMH burden, independent of age or disease duration. Associations between measures of blood pressure or hyperglycemia and WMH were not significant. Conclusions: Clinically relevant WMH are evident earlier among middle-aged patients with childhood-onset T1DM and are related to the slower information processing frequently observed in T1DM. Brain imaging in patients with T1DM who have cognitive difficulties, especially those with neuropathies, may help uncover cerebral microvascular damage. Longitudinal studies are warranted to fully characterize WMH development, risk factors, and long-term effects on cognition. © 2015 American Academy of Neurology.
Conway B.N.,Vanderbilt University |
Aroda V.R.,MedStar Research Institute |
Maynard J.D.,VeraLight |
Matter N.,VeraLight |
And 3 more authors.
Diabetes Care | Year: 2011
OBJECTIVE - To determine whether skin intrinsic fluorescence (SIF) was associated with autonomic neuropathy and confirmed distal symmetrical polyneuropathy (CDSP) in 111 individuals with type 1 diabetes (mean age 49 years, mean diabetes duration 40 years). RESEARCH DESIGN AND METHODS - SIF was measured using the SCOUT DM device. Autonomic neuropathy was defined as an electrocardiographic abnormal heart rate response to deep breathing (expiration-to-inspiration ratio <1.1). CDSP was defined using the Diabetes Control and Complications Trial clinical exam protocol (the presence of two or more of the following: symptoms, sensory and/or motor signs, and/or reduced/absent tendon reflexes consistent with DSP) confirmed by the presence of an abnormal age-specific vibratory threshold (using a Vibratron II tester). RESULTS - The prevalence of autonomic neuropathy and CDSP were 61 and 66%, respectively. SIF was higher in those with autonomic neuropathy (P < 0.0001). In multivariable analyses controlling for age and updated mean (18-year average) HbA1c, and allowing for other univariately and clinically significant correlates of autonomic neuropathy, each SD change in SIF was associated with a 2.6-greater likelihood of autonomic neuropathy (P = 0.006). Receiver operating characteristic (ROC) analyses revealed that SIF and updated mean HbA1c accounted for 80 and 57%, respectively, of the area under the curve (AUC) for autonomic neuropathy. SIF also was higher in those with CDSP (P < 0.0001) and remained so in multivariable analyses (odds ratio 2.70; P = 0.005). ROC analyses revealed that SIF and updated mean HbA1c accounted for 78 and 59%, respectively, of the AUC for CDSP. CONCLUSIONS - SIF, a marker of dermal advanced glycation end products, appears to be more strongly associated with the presence of both CDSP and autonomic neuropathy than mean HbA1c. © 2011 by the American Diabetes Association.
Aroda V.R.,MedStar Research Institute |
Conway B.N.,Vanderbilt University |
Fernandez S.J.,MedStar Research Institute |
Matter N.I.,VeraLight |
And 3 more authors.
Diabetes Technology and Therapeutics | Year: 2013
Background: This study evaluated the relationship between skin intrinsic fluorescence (SIF) and long-term mean hemoglobin A1c (HbA1c) in individuals with type 1 diabetes. Subjects and Methods: We undertook a cross-sectional analysis of 172 individuals with type 1 diabetes followed longitudinally with HbA1c data available over an average of 16.6 years. SIF was evaluated cross-sectionally using the SCOUT DS® device (VeraLight Inc., Albuquerque, NM) and correlated with most recent HbA1c and long-term mean HbA1c. Potential determinants of this relationship, including age, gender, smoking status, duration of diabetes, and renal function, were also evaluated. Results: Age-adjusted skin intrinsic fluorescence significantly correlated with long-term mean HbA1c (R=0.44, P<0.0001). In contrast, there was no significant relationship between SIF and most recent HbA1c (R=0.14, P=0.075). The best-fit model describing the relationship between SIF and mean HbA1c controlled for factors of age, duration of disease, renal function, and site of study conduct. Controlling for these factors was also important in understanding the relationship between most recent HbA1c and SIF. Evaluating longer-term HbA1c data also strengthened the relationship between SIF and mean HbA1c. In the presence of renal dysfunction or damage, as indicated by an estimated glomerular filtration rate of <60 mL/min/1.73 m2 or presence of gross proteinuria, there was no significant correlation between SIF and mean HbA1c. Conclusions: Noninvasive detection of SIF significantly correlates with long-term mean HbA1c, providing insight into long-term glycemic exposure. Age, duration of diabetes, and renal function are potential contributors to this relationship. © Copyright 2013, Mary Ann Liebert, Inc. 2013.
Orchard T.J.,University of Pittsburgh |
Lyons T.J.,University of Oklahoma |
Cleary P.A.,George Washington University |
Braffett B.H.,George Washington University |
And 7 more authors.
Diabetes Care | Year: 2013
OBJECTIVE To determine whether skin intrinsic fluorescence (SIF) is associated with longterm complications of type 1 diabetes (T1D) and, if so, whether it is independent of chronic glycemic exposure and previous intensive therapy. RESEARCH DESIGN AND METHODSdWe studied 1,185 (92%) of 1,289 active Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) participants from 2010 to 2011. SIF was determined using a fluorescence spectrometer and related cross-sectionally to recently determined measures of retinopathy (stereo fundus photography), cardiac autonomic neuropathy (CAN; R-R interval), confirmed clinical neuropathy, nephropathy (albumin excretion rate [AER]), and coronary artery calcification (CAC). RESULTSdOverall, moderately strong associations were seen with all complications, before adjustment formean HbA1c over time, which rendered these associations nonsignificant with the exception of sustained AER .30 mg/24 h and CAC, which were largely unaffected by adjustment. However, when examined within the former DCCT treatment group, associations were generally weaker in the intensive group and nonsignificant after adjustment, while in the conventional group, associations remained significant for CAN, sustained AER .30 mg/24 h, and CAC even after mean HbA1c adjustment. CONCLUSIONSdSIF is associated with T1D complications in DCCT\EDIC. Much of this association appears to be related to historical glycemic exposure, particularly in the previously intensively treated participants, inwhomadjustment for HbA1c eliminates statistical significance. © 2013 by the American Diabetes Association.