Abnormal myocardial acoustic properties in diabetic patients and their correlation with the severity of disease

Although patients with diabetes mellitus may be afflicted by cardiomyopathy, its prevalence and nature are controversial. Studies have shown that fibrosis alters the acoustic properties of the heart in animals and humans and that the changes are detectable by cardiac tissue characterization with ultrasound. The present study was performed to characterize myocardial acoustic properties in patients with insulin-dependent diabetes to determine whether ultrasound tissue characterization could detect changes potentially indicative of occult cardiomyopathy. The magnitude of cyclic variation of myocardial ultrasound integrated backscatter and its phase delay with respect to the onset of the cardiac cycle in the septum and posterior wall of the left ventricle were measured in 54 patients with diabetes who had no overt cardiac disease. Conventional echocardiography documented normal ventricular systolic function in 96%. As compared with results in age-matched patients without diabetes studied previously, cyclic variation of integrated backscatter was reduced (4.6 +/- 0.8 vs. 3.6 +/- 1.4 dB; p less than 0.001). In addition, delay was significantly increased (0.86 +/- 0.09 vs. 0.99 +/- 0.15). The primary analysis of the data focused on differences among the diabetic patients. Reduction of cyclic variation of backscatter was greatest in patients with diabetes who had neuropathy (3.2 +/- 1.0 dB; p less than 0.001) as was the increase in delay (1.04 +/- 0.16, p less than 0.001 vs. values in patients without neuropathy). Retinopathy and nephropathy were associated with abnormal myocardial acoustic properties as well. Thus, abnormalities that may reflect fibrosis or other occult cardiomyopathic changes in diabetic patients without overt heart disease are readily detectable by myocardial tissue characterization with ultrasound and parallel the severity of noncardiac diabetic complications.

Change in metabolic control and functional status after hospitalization. Impact of patient activation intervention in diabetic patients

OBJECTIVE

To determine whether a short intervention to enhance patient information seeking and decision making during hospitalization results in improved metabolic control and functional status in patients with diabetes mellitus.

RESEARCH DESIGN AND METHODS

A randomized clinical trial was conducted in which control patients received a comprehensive 3-day evaluation and educational program, whereas experimental patients received a 45-min patient activation intervention and a 1-h self-administered booster in addition to the program. Metabolic control and functional status were measured at baseline and 4 mo postdischarge.

RESULTS

During their discharge discussions, experimental patients asked significantly more questions than control patients (7.4 vs. 3.0, P less than .001) and 4 mo later reported significantly fewer physical limitations in activities of daily living than the control group (P = 0.02). Improvement in metabolic control was statistically significant only for experimental patients (P = 0.02), although their glycosylated hemoglobin levels were not significantly lower than control patients' at follow-up. The intervention did not diminish physician satisfaction with patient interactions, although it may have increased physician frustration with responsibilities that competed with patient care.

CONCLUSIONS

These results suggest that the addition of a patient activation intervention to a comprehensive diabetes management program may substantially enhance physical functioning among adults with diabetes mellitus.

Relationship of personality characteristics to glucose regulation in adults with diabetes

Personality characteristics were assessed in 139 diabetic adults (insulin-dependent diabetes mellitus = 84, non-insulin-dependent diabetes mellitus = 55) to determine whether a relationship existed between glucose regulation and the measured psychological features. Cloninger's Tridimensional Personality Questionnaire (TPQ) was used to evaluate personality while glycated hemoglobin provided an estimate of recent glucose control. Mean glycated hemoglobin (gHb) for the sample was 11.4%. A significant difference (p = 0.03) in gHb levels was observed comparing subjects with extreme personality features (mean = 11.9%) with those subjects with average personality profiles (mean = 10.9%). Post hoc statistical testing identified opportunistic, alienated, and explosive temperaments as the personality features most often associated with poor glucose control. The TPQ appeared to be a particularly useful predictor of poorer glucose regulation in the subset of patients who were self-referred.

Self-care predictors of metabolic control in NIDDM patients

The objective of this study was to evaluate whether the relationship between self-care behavior and metabolic control is comparable in patients with non-insulin-dependent diabetes mellitus (NIDDM) on insulin and not on insulin. We studied 84 NIDDM patients hospitalized for an elective admission in Washington University's Model Demonstration Unit. At admission, patients reported the frequency of exercise, blood glucose monitoring, and meal skipping for the previous 2 wk. Metabolic control over the previous 8-12 wk was determined from glycosylated hemoglobin assays. In cross-sectional analysis controlling for patient sociodemographic and health characteristics, glycosylated hemoglobin levels were positively related to meal skipping (P = 0.0008) and negatively related to the frequency of blood glucose monitoring (P = 0.0025). Self-care behaviors explained 26% of the variance in glycosylated hemoglobin levels in NIDDM patients. Multivariate modeling demonstrated no significant interaction effects between insulin treatment and self-care on metabolic control. In conclusion, these findings support the clinical significance of self-care activities for metabolic control in NIDDM patients, particularly meal skipping and blood glucose monitoring.

Role of insulin in management of surgical patients with diabetes mellitus

Because surgery is a likely event during the lifetime of patients with diabetes, health-care team members need to be aware of the metabolic problems that may occur during the perioperative period. Surgery, especially in the presence of general anesthesia, will produce a diabetogenic response. This is generally due to an elevation of counterregulatory hormones, although endogenous insulin is also suppressed. The excessive lipolysis and ketogenesis that can occur during surgery can have particularly deleterious effects for patients with diabetes. Thus, sufficient insulin must be provided during this period to suppress these catabolic processes. The major controversy regarding surgery and diabetes concerns the route of insulin administration. This article reviews the various treatment options for patients with insulin-dependent and non-insulin-dependent diabetes mellitus, with particular emphasis on the role of insulin. Special situations, e.g., outpatient surgery, coronary artery bypass, and emergency surgery, are also discussed.

The effect of amino acids, monoamines and polyamines on pyruvate dehydrogenase activity in mitochondria from rat adipocytes

The ability of polyamines and other cationic compounds including monoamines, amino acids, poly-L-arginine, poly-D-lysine and poly-L-lysine, to alter pyruvate dehydrogenase (PDH) activity in mitochondria from rat epididymal adipocytes was determined. PDH was assayed with the substrate [1-14C] pyruvate in the presence of 0.05 mM Ca2+ and Mg2+. Nine of the fourteen compounds tested at 0.1 mM caused a significant increase (procaine, 3-(beta-morpholinopropionyl) benzo [b]thiophene [VII], spermine, spermidine, putrescine, lysine and tryptophan) or decrease (poly-L-arginine, 3-(beta-piperidinopropionyl) benzo[b]thiophene) in PDH activity. None of these compounds nonenzymatically decarboxylated [1-14C] pyruvate to release 14CO2. NaF, a PDH phosphatase inhibitor, suppressed the stimulatory effects of those compounds tested: procaine, tryptophan, VII, spermine and spermidine. These results imply that these five compounds activate PDH activity through stimulation of the PDH phosphatase. When the Mg2+ concentration was increased from 0.05 to 4.5 mM, the stimulatory effect of spermine was increased, consistent with the finding by others that spermine lowers the Km of the enzyme for Mg2+. However, at Mg2+ concentrations greater than 0.3 mM, the stimulatory effect of VII was unaltered, procaine failed to alter PDH activity, lysine inhibited PDH activity, and poly-L-lysine stimulated PDH activity. Therefore, polyamines and other positively charged small molecules may be physiologic regulators of PDH activity.