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Biomedical subjects

R E Maser

Publications and source records attributed to R E Maser.

At least 19 recordsLinked to original sources
PubMed2003

Do plasminogen activator inhibitor (PAI-1) or tissue plasminogen activator PAI-1 complexes predict complications in Type 1 diabetes: the Pittsburgh Epidemiology of Diabetes Complications Study.

AIMS: To examine the predictive power of plasminogen activator inhibitor-1 (PAI-1) and the complexes it forms with tissue plasminogen activator (tPA-PAI-1) for the two major Type 1 diabetes (T1D) complications (coronary artery disease (CAD) and overt nephropathy) in the context of standard risk factors. METHODS: Observational prospective study of 454 participants with childhood onset (< 17 years) T1D, aged 18+ years at baseline. PAI-1 and tPA-PAI-1 were determined using ELISA methodology. Follow-up (6 years) was limited to 382 individuals for CAD and 294 individuals for overt nephropathy, after excluding baseline cases. Total, HDL and LDL-cholesterol, triglycerides, HbA1, blood pressure, body mass index (BMI), waist-hip ratio (WHR), leucocyte count, Beck depression score and fibrinogen were also examined. RESULTS: The 56 incident cases of CAD had marginally lower PAI-1 and higher tPA-PAI-1 levels compared with those free of CAD. However, marginally higher PAI-1 and significantly higher tPA-PAI-1 (P = 0.04) levels were seen in those who developed nephropathy. After controlling for age, both PAI-1 and tPA-PAI-1 showed significant negative correlations with HDL-cholesterol, and positive correlations with triglycerides, WHR, HbA1 and fibrinogen. tPA-PAI-1 was also positively correlated with total and LDL-cholesterol. In multivariate analyses, neither PAI-1 nor tPA-PAI-1 was an independent predictor of CAD or overt nephropathy. CONCLUSIONS: These results suggest little association between PAI-1 and later CAD in patients with T1D. However, tPA-PAI-1 complexes may be involved in the pathogenesis of overt nephropathy.

Adult↗
PubMed2002

Obesity is not a confounding factor for performing autonomic function tests in individuals with diabetes mellitus.

AIM: Cardiovascular autonomic neuropathy is a serious complication of diabetes mellitus. Previous studies have revealed conflicting results with regard to the role of obesity and its effect on the performance of tests (e.g. RR-variation during deep breathing) for the determination of the presence of cardiovascular autonomic dysfunction. The objective of this study was to determine if obesity affects the performance and the reproducibility of autonomic function tests. METHODS: This cross-sectional study included 159 diabetic individuals. Autonomic function tests included: RR-variation during deep breathing and the Valsalva ratio. These tests were assessed using the ANS2000 ECG Monitor and Respiration Pacer. RR-variation was measured by vector analysis (i.e. mean circular resultant, MCR). Reproducibility of the autonomic function tests was assessed by determining the coefficient of variation (CV) on repeat testing. RESULTS: Using cut-off points to describe normal weight (body mass index (b.m.i.) < or = 25 kg/m(2)), overweight (b.m.i. 25.01-30 kg/m(2)), obese (b.m.i. 30.01-40 kg/m(2)), and morbidly obese (b.m.i. > or = 40.1 kg/m(2)), no difference was found for the MCR, Valsalva ratio, CV of the MCR, or CV of the Valsalva ratio among the various weight levels for individuals with type 1 or type 2 diabetes. CONCLUSIONS: The results of this study indicate that obesity is not a confounding factor in the performance of autonomic function tests. Likewise, the reproducibility of autonomic function testing is not affected by obesity. Assessment of autonomic function is important for obese and non-obese individuals given that reduced RR-variation is associated with exercise intolerance, intraoperative cardiovascular lability and increased risk of mortality.

Adult↗
PubMed1999

Over-the-counter yellow ultraviolet light protective lenses: any benefit for individuals with diabetes mellitus?

The use of yellow UV protective lenses did improve some individual's ability to see even under artificial and controlled circumstances. Each test, although given in random order, cannot be interpreted to demonstrate the full range of benefit. The improvement for most was modest. Any improvement was most likely due to increased contrast. Light of a short wavelength is scattered more than long wavelength light. The yellow UV protective lenses block light of a short wavelength, thus reducing scatter and increasing contrast. Therefore, patients with visual problems of increased scatter would be expected to demonstrate the greatest improvement. We did not test for the duration of benefit. Subjective reports, from other patients, who have routinely used these lenses (only yellow lens-naive patients were included in the trial) suggest that the benefit increased with duration of use. Patients who routinely use the yellow UV protective lenses state that due to the increased contrast, they squint less. This seems to be most true at dusk. These regular users note that both their eyes are less tired and driving, in particular, is less stressful with the use of yellow lenses. The small benefit might conceivably be magnified in a real world setting. Given that the lenses cost only $10 to $15 and can be purchased in any sporting goods store, even our small measured improvement is likely to be worthwhile. Finally, patients were tested with "off-the-shelf" yellow lenses. To benefit patients the study was designed for their convenience and the low purchase price. The color of the lenses can be chosen to maximize the desired effect. We did not test various wavelength yellow lenses. Consequently, there may be better, albeit more expensive, yellow/orange lenses which might be designed explicitly for this purpose. In summary, the use of these yellow "sunglasses" might provide some improvement in sight for diabetic patients while keeping expense to a minimum.

Color↗
PubMed1998

The new diagnosis and classification of diabetes mellitus.

We are in the midst of an epidemic of diabetes, and the prevalence appears to be especially marked within Delaware. To prevent tragic long-term complications of diabetes, and to minimize the enormous costs associated with treating them, an emphasis must be placed on the early diagnosis and aggressive management of diabetes. The changes in the classification, diagnosis and screening for diabetes should help to redirect the focus to one of preventive care.

Delaware↗
PubMed1998

Intravenous insulin infusion therapies for postoperative coronary artery bypass graft patients.

BACKGROUND: Hyperglycemia is very common in postoperative coronary artery bypass graft patients. Although sliding scale insulin therapy is often used, there is no standard of care for the management of hyperglycemia. METHODS: Different intravenous insulin therapies were used in three consecutive sets of hyperglycemic postoperative coronary artery bypass graft patients. The first method was a sliding scale intravenous insulin regimen beginning with four units/hr, and increasing by four units/hr each hourly bedside arterial whole blood glucose measurement greater than 250 mg/dL (13.9 mmol/L) (n = 58). The second and third methods were constant insulin infusions at a rate of eight units (n = 60) and 20 units/hr (n = 51) respectively. Insulin infusions were reduced to two units/hr when the glucose concentration decreased to 150-250 mg/dL (8.3-13.9 mmol/L), and was stopped when it fell below 150 mg/dL (8.3 mmol/L). RESULTS: Thirty percent of patients undergoing coronary artery bypass grafting had a diagnosis of diabetes mellitus. Forty-eight percent of all patients had a glucose value greater than 250 mg/dL (13.9 mmol/L) within the first 24 hours postoperatively. The three intravenous insulin infusion regimens produced similar control of arterial whole blood glucose concentrations. Patients with high initial glucose concentrations (greater than 400 mg/dL) (22.2 mmol/L) required intravenous insulin therapy for ten or more hours before attaining the target range of 151-250 mg/dL (8.3-13.9 mmol/L). CONCLUSIONS: Constant-rate intravenous insulin therapy is effective in lowering arterial whole blood glucose concentrations in postoperative coronary artery bypass graft patients. Initiation of intravenous insulin therapy at lower glucose values reduces the time necessary for the infusion.

Coronary Artery Bypass↗
PubMed1997

Vibratory thresholds correlation with systolic blood pressure in diabetic women.

Previous studies have suggested a potential association of elevated blood pressure (BP) and the development of diabetic neuropathy for individuals with insulin-dependent diabetes mellitus. In this study, we examined an association between BP and vibratory thresholds (assessment modality of large sensory nerve fiber function) for 33 participants with non-insulin-dependent diabetes mellitus. There were 19 women and 14 men aged 58 +/- 7 (mean +/- SD) years, with diabetes duration of 7 +/- 6 years and a body mass index of 29 +/- 5 kg/m2. None of the individuals were taking any medications that lower BP and all were negative for the presence of microalbuminuria. Vibratory thresholds were determined at three visits using a two-alternative, forced-choice procedure. BP was assessed by 24-h ambulatory BP monitoring. As expected, vibratory thresholds were higher for men than for women (6.3 +/- 4 v 4.2 +/- 3 vibration units) but there was no statistical difference after controlling for height. In multivariate analyses with vibratory thresholds as the dependent variable, duration of diabetes (P < 0.01), age (P < .01) and systolic BP (SBP) (P < .01) explained approximately 70% of the overall variability of the gender-specific (ie, female) model. The variability was similar (ie, 70% to 73%) no matter which SBP measure was available for modeling. In terms of diastolic blood pressure (DBP) measures, only the percentage of abnormal readings (ie, > 90 mm Hg) for day DBP was found to be independently associated with vibratory thresholds for women. The association of BP and large sensory nerve fiber dysfunction for nonnephropathic diabetic women found in this cross-sectional study warrants further investigation.

Blood Pressure↗
PubMed1997

Hypertension as a risk factor for diabetic neuropathy: a prospective study.

The pathogeneses of diabetic neuropathy is still unclear. This study prospectively investigated the risk factors for distal symmetrical polyneuropathy (DSP) in a cohort of childhood-onset IDDM patients. Subjects from the Epidemiology of Diabetes Complications (EDC) Study were clinically examined at baseline and then biennially. DSP was diagnosed by a combination of clinical criteria, symptoms and signs (Diabetes Control and Complications Trial [DCCT] exam), and quantitative sensory threshold (QST). Among the 463 (70.4%) subjects who were free of DSP at baseline, 453 (97.8%) participated in at least one biennial reexamination during the first 6 years of follow-up and were included in the current analysis. A total of 68 (15.0%) subjects developed DSP in 6 years, giving a cumulative probability of 0.29. The Cox proportional hazards model shows that longer IDDM duration, hypertension, poor glycemic control, height, and smoking were all independent predictors of the incidence of DSP (all P < 0.0001, except for smoking for which P = 0.03). Hypertension showed the greatest impact on the development of DSP for individuals with either short or long IDDM duration. This study confirms some risk factors for DSP found in cross-sectional studies and suggests a strong relationship between hypertension and DSP. The results indicate that in addition to good glycemic control, avoidance of smoking and good blood pressure control may be helpful in preventing or delaying the onset of DSP in IDDM patients.

Adolescent↗
PubMed1997

A cross-sectional study comparing two quantitative sensory testing devices in individuals with diabetes.

OBJECTIVE: This study was designed to compare circumference discrimination thresholds, as assessed by the Tacticon (Tacticon, Inc., Westtown, PA), a new quantitative sensory testing (QST) device, with vibratory thresholds, an assessment modality of large sensory nerve fibers, in individuals with diabetes. RESEARCH DESIGN AND METHODS: In this study, 150 individuals with diabetes were evaluated. Vibratory thresholds and circumference discrimination thresholds, evaluated with the Tacticon, were determined using a two-alternative forced-choice procedure. RESULTS: Vibratory thresholds increased with decreasing ability to discriminate differences in circumference (P < 0.001) for those below and above 50 years of age. Agreement between the two QST devices was assessed via the kappa-statistic in both age-groups (i.e., < or = 50 years old [kappa = 0.67], > 50 years old [kappa = 0.55]). In multiple logistic regression, where circumference discrimination thresholds were the dependent variable, age, duration of diabetes, and height were found to be independently associated for those > 50 years old. CONCLUSIONS: The Tacticon offers a simple method of assessing the complex function of area discrimination. Our results suggest that the Tacticon can detect neuropathy in the primary care setting. Its cost, portability, and ease of use provide some advantages over existing QST equipment.

Adult↗
PubMed1996

Why does diabetic autonomic neuropathy predict IDDM mortality? An analysis from the Pittsburgh Epidemiology of Diabetes Complications Study.

BACKGROUND: Previous studies have suggested that IDDM subjects with diabetic autonomic neuropathy (DAN) have a greatly increased risk of mortality which may relate to a specific cardiologic etiology. OBJECTIVES: To examine the predictors of DAN in IDDM and its relationship to subsequent mortality. STUDY POPULATION: The Epidemiology of Diabetes Complications Study based on an incident cohort of childhood onset IDDM subjects. Data from two examinations, separated by 2 years, are utilized. METHODS: Diabetic autonomic neuropathy was determined by Expiration/Inspiration (E/I ratio). A variety of baseline risk factors were related to its subsequent incidence (n = 57 out of 325 subjects free of DAN at baseline). Two-year mortality by DAN status was also determined for all 479 subjects seen at baseline. RESULTS: Duration of diabetes, the cardiovascular risk profile (hypertension, elevated LDL cholesterol and triglycerides), and other complications (e.g. nephropathy) were all univariately associated with subsequent DAN (P < 0.01). Smoking status and hemoglobin A1 (HbA1) but less strongly, related (P < 0.05). Cox proportional hazards modeling showed diabetes duration and HbA1 to be significant independent predictors. Distal Symmetrical Polyneuropathy also contributed if added to the model. Mortality was increased four-fold in those with DAN (P = 0.005), although this difference no longer was significant after adjustment for baseline nephropathy (P = 0.35) or hypertension (P = 0.42). CONCLUSIONS: Duration of diabetes and HbA1 are the major predictors of DAN. However, although DAN is clearly associated with increased mortality, this is largely explained by associations with complications (e.g. nephropathy) and increased cardiovascular risk factors (e.g. hypertension).

Adult↗
PubMed1996

Glucose monitoring of patients with diabetes mellitus receiving general anesthesia: a study of the practices of anesthesia providers in a large community hospital.

Surgical stress causes hyperglycemia with potential complications (e.g., impaired granulocytic function and delayed wound healing) particularly when glucose levels exceed 250 mg/dL. Standards of care for patients with diabetes undergoing surgery may vary by geographic locale, type of surgical procedure, and type of diabetes. We explored whether anesthesia providers monitor glucose levels in patients with diabetes. Records of 100 patients with diabetes who underwent surgery under general anesthesia (length of procedure: range, 1.9-11.8 hours) were reviewed. Demographic information, glucose levels, frequency of glucose monitoring, and treatment used for diabetes management preoperatively, intraoperatively, and postoperatively were recorded. There were 46 males and 54 females, aged 62 +/- 13 years (55% currently treated with insulin). Of the study cohort, 89% had preoperative, 23% had intraoperative, and 54% had postoperative glucose monitoring performed. As expected, postoperative glucose concentrations were significantly higher than preoperative glucose levels (mean difference, 99 mg/dL, P < .01). The mean postoperative glucose level was 262 +/- 89 mg/dL with 30 of the 54 monitored patients having a postoperative glucose level greater than 250 mg/dL. Individuals treated with insulin and those who underwent major surgery were more likely to have glucose levels monitored. These results suggest that better strategies for monitoring glucose levels during the surgical period are needed.

Aged↗
PubMed1995

A comparison between alternative and trade name glucose test strips.

OBJECTIVE: To determine the reliability of seven different alternative glucose test strips manufactured for use with three different glucose meters. RESEARCH DESIGN AND METHODS: Venous blood samples were obtained from volunteers to test trade name glucose test strips on the manufacturers' glucose meters (One Touch II, Glucometer II, and Glucometer III), and the remainder of each sample was used for laboratory determination of blood glucose levels. In addition to the trade name test strips, Quick Check and First Choice test strips were tested on all meters, and Biotel test strips were also tested on the Glucometer III. RESULTS: In linear regression analysis, the R2 ranged from 0.84 to 0.97 for the test strips compared with plasma glucose values. The test strips with the highest accuracy and precision at all ranges of blood glucose levels were the One Touch II and Glucometer III trade name strips and the Quick Check and First Choice alternative strips for the One Touch II glucose meter and the First Choice alternative strip for the Glucometer II. Subgroup analysis based on ranges of blood glucose values, however, revealed that the alternative strips were not as accurate as the trade name test strips, with the exception of the First Choice alternative test strip for the Glucometer II. All of the trade name test strips were more precise than the alternative test strips designed for the individual meters. CONCLUSIONS: Alternative glucose test strips can be used to predict the actual laboratory blood glucose values but are generally not as accurate or precise as the trade name test strips.

Blood Glucose↗
PubMed1994

Use of arterial blood with bedside glucose reflectance meters in an intensive care unit: are they accurate?

OBJECTIVE: To compare blood glucose values obtained from two different sampling sites (arterial catheter and capillary from finger puncture), which were analyzed by a bedside reflectance meter. A sample was also analyzed by standard methods (oxygen electrode oxidation in the laboratory). DESIGN: Prospective, cross-sectional clinical study. SETTING: Cardiovascular intensive care unit (ICU) designed for postoperative open-heart surgery patients in a 1,100-bed medical center. PATIENTS: Sequential sample of 50 patients immediately after open-heart surgery. MEASUREMENTS AND MAIN RESULTS: The blood glucose concentration of each patient was analyzed on the patient's arrival to the ICU (immediately postoperatively) by three methods: one blood specimen was obtained from an arterial catheter, divided and analyzed either at the bedside by a reflectance meter (glucose method 1) or in the hospital laboratory (glucose method 2); another sample was obtained by lancing the fingertip and the glucose concentration was analyzed at the bedside in the same reflectance meter (glucose method 3). Using paired analyses to compare the mean glucose values of the bedside arterial whole blood sample (method 1) with the arterial serum sample (method 2) demonstrated that the glucose concentration in the arterial whole blood sample (method 1) was significantly (p < .001) higher. For 46 of 50 comparisons, the glucose value in the arterial whole blood sample (method 1) was higher, with a mean difference of 30 mg/dL (1.7 mmol/L). Although the mean difference was reduced to 10 mg/dL (0.6 mmol/L) when the arterial whole blood sample (method 1) was corrected for the hematocrit (i.e., < 35% [< 0.35]), the mean glucose concentration in the arterial whole blood samples (method 1) remained statistically higher (p < .05). The glucose concentration in the arterial serum sample (method 2) was significantly higher than the value determined from the bedside capillary sample (method 3) before (p < .05) and after (p < .001) correction for hematocrit. The difference in mean glucose concentrations between the arterial serum sample (method 2) and bedside capillary sample (method 3) was 9 mg/dL (0.5 mmol/L) when the capillary specimen (method 3) was not corrected for hematocrit. This difference increased to 21 mg/dL (1.2 mmol/L) when low hematocrit values were considered and appropriate adjustments of the glucose values were made. At the bedside, one can accurately correct arterial whole blood glucose values to correspond to laboratory values by the following formula: (0.94 x arterial whole blood glucose) + (4.6 x hematocrit) + (-16.5 x [37 degrees C--patient's temperature])--132 = laboratory glucose value. CONCLUSIONS: Since arterial whole blood samples give higher glucose results than arterial serum, the use of arterial whole blood in combination with reflectance meters must be recommended with caution. This caution is especially advised if the glucose values obtained with arterial whole blood are used in conjunction with a sliding scale of insulin, which depends on threshold concentrations of glucose. In our hospital, use of arterial whole blood in combination with reflectance meters could have resulted in an incorrect dose of insulin in 31 of 50 patients.

Adult↗
PubMed1993

The effects of age and diabetes mellitus on nerve function.

OBJECTIVE: This project evaluated the association of age and vibratory thresholds (assessment modality of large sensory nerve fibers) in subjects with and without diabetes mellitus. DESIGN: Cross-sectional study. SETTING: Medical Research Institute of Delaware. PARTICIPANTS: Individuals with non-insulin-dependent diabetes mellitus and non-diabetic control subjects. MEASUREMENTS: Vibratory thresholds were examined in four age groups (ie, < 45 yrs, 45-54 yrs, 55-64 yrs, > or = 65 yrs). The independent association of age, duration of diabetes, height, gender, glycemic control, and smoking history were analyzed in terms of their relationship to vibratory thresholds. MAIN RESULTS: Vibratory thresholds increased with age for both control and diabetic subjects. Comparing controls with diabetic subjects in the same age categorizes revealed significant differences for vibratory thresholds only in the > or = 65 year old age group. Modeling with vibratory thresholds as the dependent variable showed that age and male gender were independently associated with vibratory thresholds for the controls and explained the majority of the variability (R2 = 0.79). Age, duration of diabetes, and height were independently associated with vibratory thresholds for the diabetic subjects but explained much less of the variability (R2 = 0.39). CONCLUSIONS: The results suggest an acceleration of the natural aging process for large sensory nerve fiber function in diabetic subjects. Thus, young diabetic subjects may be at a risk of lower extremity complications as a result of injuries similar to that older non-diabetic individuals.

Adult↗
PubMed1993

Lipoprotein(a) concentration shows little relationship to IDDM complications in the Pittsburgh Epidemiology of Diabetes Complications Study cohort.

OBJECTIVE: To examine the potential associations of lipoprotein(a) and the complications of IDDM and their risk factors. RESEARCH DESIGN AND METHODS: This report focuses on 186 individuals with IDDM (mean age = 34 yr) participating in a 10-yr prospective study examining various complications. Lp(a) concentrations were evaluated for those with and without complications. RESULTS: A weak correlation was seen between Lp(a) and HbA1 (r = 0.16, P < 0.05). Lp(a) concentrations were not significantly different for those with or without proliferative retinopathy, overt nephropathy, peripheral vascular disease, or definite myocardial infarction or angina. However, an inverse association (P < 0.05) was seen with distal symmetric polyneuropathy. These results were also confirmed by categorical analyses (i.e., Lp(a) levels < or = 30 vs. > 30 mg/dl). CONCLUSIONS: These results suggest that any association of Lp(a) concentration with IDDM complications is likely to be weak or nonexistent. However, prospective studies are needed before its full role can be determined.

Adult↗
PubMed1992

Problems with gait and posture in neuropathic patients with insulin-dependent diabetes mellitus.

Peripheral neuropathy secondary to diabetes mellitus is believed to cause postural instability and uncoordinated gait, although this is not well documented. Two groups of patients from the Pittsburgh Epidemiology of Diabetes Complications Study, matched for age and duration of Type 1 diabetes, but with significantly different vibratory sensation thresholds as determined by Vibratron II testing, were therefore surveyed. The mean ages were 32.9 and 31.9 years and durations of diabetes were 22.0 and 18.8 years for the neuropathic and control groups, respectively. Patients provided details of fall injuries, and perception of safety during standing and walking. Multiple linear and logistic regression models were used to account for potentially associated variables such as gender, retinopathy, and duration of diabetes. The neuropathic group had adjusted odds ratios for reported injuries during gait of 15.0 relative to the control group (95% confidence intervals 1.04-216.59). The neuropathic group also reported significantly lower scores (less safe, p = 0.004) than the control group on perceived safety in unusual conditions. It is concluded that peripheral neuropathy has an effect on gait and posture which is clinically significant and that this effect merits further biomechanical study in neuropathic patients.

Accidental Falls↗
PubMed1992

Pittsburgh Epidemiology of Diabetes Complications Study. Measuring diabetic neuropathy follow-up study results.

OBJECTIVE: This project evaluated the utility of quantitative sensory techniques in predicting the development of neuropathy for subjects participating in a prospective study. RESEARCH DESIGN AND METHODS: Distal symmetric polyneuropathy was evaluated in 77 insulin-dependent diabetes mellitus individuals via quantitative sensory testing, nerve conduction studies, and clinical examination. RESULTS: Although the specificity and positive predictive value were low for the quantitative sensory techniques as predictors of neuropathy diagnosed on clinical exam approximately 2 yr later, the sensitivity for vibratory thresholds was high (100%). Variability over the 2-yr interval was shown on follow-up testing for each of the objective assessment modalities and it was not explained by differences for potential risk factors measured at baseline. CONCLUSION: Despite a cross-sectional relationship between the assessment modalities and clinically overt neuropathy at baseline, these follow-up data suggest that the potential for the objective modalities as predictors of clinically diagnosed neuropathy may be limited.

Adult↗