To maximize disease control, patients must participate effectively in their medical care. The authors developed an intervention designed to increase the involvement of patients in medical decision making. In a 20-minute session just before the regular visit to a physician, a clinic assistant reviewed the medical record of each experimental patient with him/her, guided by a diabetes algorithm. Using systematic prompts, the assistant encouraged patients to use the information gained to negotiate medical decisions with the doctor. A randomized trial was conducted in two university hospital clinics to compare this intervention with standard educational materials in sessions of equal length. The mean pre-intervention glycosylated hemoglobin (HbA1) values were 10.6 +/- 2.1% for 33 experimental patients and 10.3 +/- 2.0% for 26 controls. After the intervention the mean levels were 9.1 +/- 1.9% in the experimental group (p less than 0.01) and 10.6 +/- 2.22% for controls. Analysis of audiotapes of the visits to the physician showed the experimental patients were twice as effective as controls in eliciting information from the physician. Experimental patients reported significantly fewer function limitations. The authors conclude that the intervention is feasible and that it changes patient behavior, improves blood sugar control, and decreases functional limitations.

Hyperinsulinemia has been implicated as a separate risk factor for the development of accelerated cardiovascular disease, but the mechanism is unknown. Recently, we and several other groups have shown that insulin stimulates the production and secretion of the vasoconstrictor peptide endothelin-1 (ET-1) from vascular endothelial cells, and hyperinsulinemia results in increased plasma ET levels in vivo. However, the interactive effects of diabetes, insulin, and glucose on ET target tissues, like those on vascular smooth muscle cells (VSMC), are not well defined. In these studies, we examined the effects of the diabetic factors on ET receptors and [3H]thymidine incorporation into cultured cells prepared from control, streptozocin-diabetic, insulin-treated diabetic, and hyperinsulinemic rats. Scatchard analysis of saturation binding studies revealed a 2-fold increase in ET receptor number in normal VSMC treated in vitro with insulin, whereas glucose had no significant effect. Neither treatment affected receptor affinity. Similarly, aortic smooth muscle cells, brain capillary pericytes, and kidney afferent arteriolar smooth muscle cells from rats made hyperinsulinemic in vivo each showed approximately a 2-fold increase in receptor number. This increase in receptor density probably resulted from the stimulation of receptor protein production, because insulin caused a maximal 2.3 +/- 0.3 (+/- SEM) fold increase in the ETA receptor mRNA expressed in cultured VSMC by 4 h. Both insulin and ET significantly increased thymidine incorporation in aortic VSMC, but ET-1 was much more potent in this regard. However, the combined effects of insulin plus ET-1 resulted in a 10-fold increase in this index of cell proliferation, significantly different from the effects of either peptide alone. We postulate that hyperinsulinemia in vivo may potentiate ET release and receptor-mediated action, thereby contributing to vascular disease in the setting of diabetes.

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The processing and secretion of atrial natriuretic peptide (ANP) from neurons and the expression of high-affinity receptors on astroglia from primary cultures of fetal rat diencephalon have recently been demonstrated. Thus natriuretic peptides may play a role in neuronal-glial signaling, but a physiological role has not been characterized. In these studies, we show that ANP and brain natriuretic peptide significantly (P less than 0.05) decrease the incorporation of [3H]thymidine into astroglia in the presence of fetal bovine serum and inhibit the proliferation of these cells in the presence or absence of serum. These effects were evident at concentrations of natriuretic peptides (10(-10) M) characteristic of the receptor Kd and were not seen in cultured bovine brain capillary endothelial cells, another brain cell expressing high-affinity receptors for the natriuretic peptides. The antiproliferative effects were potently produced by ANP-(4-23), a ring-deleted analogue of ANP-(1-28), which at the concentrations used in this study binds only to the C or low-molecular-weight natriuretic peptide receptor. Thymidine incorporation was not affected by adenosine 3',5'-cyclic monophosphate (cAMP), the inhibition of which has been proposed to mediate postbinding signaling of the C receptor. Epidermal growth factor (10(-9) M) produced an 87% increase in thymidine incorporation, which was not significantly inhibited by either form of ANP. Thus natriuretic peptides in the brain may serve as antigrowth factors for glia through binding to a receptor previously felt to function solely in peptide clearance. The inhibitory effects are not the result of inhibiting the proliferative effects of an endogenous growth factor and are cAMP independent.

Endothelin, a vasoconstrictor peptide secreted from endothelial cells, has been thought to play a role in various forms of vascular disease. Diabetes mellitus is well known for its association with accelerated atherosclerosis and microvascular damage. Although the basis for the vessel insult is multifactorial, hyperinsulinemia is thought to contribute by an unknown mechanism. In this study, we sought to determine whether insulin stimulates the production and secretion of ET-1 as a possible basis for the association of hyperinsulinemia and vascular disease. We demonstrated that insulin significantly stimulates the gene expression and secretion of ET-1 from cultured BAEC, and that insulin increases ET-1 mRNA expressed in BBCEC. Insulin caused a maximal twofold inducement above control ET-1 mRNA expression in a dose-related fashion in BAEC. The increased mRNA resulted from increased transcription, as determined by nuclear run-off studies. Increased ET-1 mRNA was seen after 4 h of incubation with insulin: the peak occurred at 6-8 h and persisted for 24 h. Insulin caused as much as a fourfold stimulation of ET-1 secretion from BAEC in a dose-related fashion, including a twofold increase at a physiological concentration (10(-9) M): The increase began at 1 h of incubation and continued for the entire 24-h incubation period. The insulin-induced increases in both ET-1 mRNA and ET-1 protein secretion were significantly attenuated by genistein, a tyrosine kinase inhibitor. This stimulation probably occurred through the insulin receptor, because IGF-1 had no effect on ET-1 gene expression or secretion from these cells.(ABSTRACT TRUNCATED AT 250 WORDS)