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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The association of obesity with hypertension has been amply demonstrated in cross-sectional, longitudinal, and dietary-intervention studies, but the mechanisms remain enigmatic. Both conditions are independently characterized by similar metabolic alterations, i.e., glucose intolerance, dyslipoproteinemia, elevated serum uric acid, and inadequate Na+ transport. Obesity, hypertension, and these metabolic alterations are associated with hyperinsulinemia/insulin resistance. The degree of these alterations is lowest in lean hypertensives, intermediate in obese normotensives, and greatest in obese hypertensives, but mortality risk is highest in lean hypertensives. This apparent discrepancy may be related to the divergent hemodynamic characteristics, possibly indicating different etiology, of lean and obese hypertensives, i.e., contracted blood volume, increased total vascular peripheral resistance, and normal sympathetic drive in the former, expanded blood volume, normal peripheral resistance, and increased sympathetic drive in the latter. Current knowledge suggests that the interrelationships of obesity and hypertension with the metabolic alterations could be mediated by high carbohydrate and fat consumption and low physical activity, resulting in obesity and separate pathways in hyperinsulinemia and increased sympathetic drive, leading to a double vicious cycle. In one, hyperinsulinemia and the consequent insulin resistance would compound one another. In the second, the increasing hyperinsulinemia would increasingly stimulate the sympathetic nervous system. This double vicious cycle could result in increasing hemodynamic and metabolic derangements causing hypertension, diabetes, and atherosclerotic cardiovascular disease (ASCVD). The association of lean hypertension with ASCVD may be through other mechanisms, e.g., hemodynamic forces on the vascular endothelium.
Diabetes Care 1991 Jun
PMID:Hyperinsulinemia or increased sympathetic drive as links for obesity and hypertension. 186 20

We tested the hypothesis that dysfunction of vascular endothelium, indicated by an increase in plasma level of von Willebrand factor (vWF), is present in patients with insulin-dependent diabetes mellitus (IDDM) who develop diabetic nephropathy (DN). DN was classified as absent (urinary albumin excretion [UAE] rate less than 15 microgram/min), incipient (UAE rate 15-200 micrograms/min), or clinical (UAE rate greater than 200 micrograms/min). We followed a cohort of 59 patients for a median of 3 yr. At baseline, 52 patients had no DN, 6 had incipient DN, and 1 had clinical DN. At follow-up, 38 patients had no DN (group 1). Incipient DN had developed in 14 patients and worsened in 3 patients. Clinical DN had worsened in 1 patient. Together, these 18 patients comprised group 2. A decrease in UAE was observed in the remaining three patients with incipient DN at baseline (group 3). In group 1, vWF--measured by immunoelectrophoresis and expressed as a percentage of normal--increased slightly (median 10%, range -43 to 145, P = 0.009). In group 2, vWF increased in all patients (median 80%, range 14 to 206 [corrected], P = 0.0002 vs. baseline and group 1). In group 3, vWF decreased (median -19%, range -44 to -18). After correction for possible confounders, i.e., age, varying duration of follow-up, and initial level of vWF, the difference in vWF change between groups 1 and 2 remained significant (P = 0.009). Poor glycemic control at baseline, estimated by glycosylated hemoglobin, was a significant predictor of increases in vWF in both group 1 and groups 1 and 2 combined.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes 1991 Aug
PMID:von Willebrand factor and development of diabetic nephropathy in IDDM. 190 50

Thrombomodulin (TM) is a membrane protein in the vascular endothelium, and it plays an important role as a cofactor in the thrombin-catalyzed activation of protein C. It has also been found in human plasma; however, its clinical significance is not known. In this study, fasting plasma TM concentrations in 67 diabetic patients with different degrees of albuminuria (39 men aged 57 +/- 8 yr, 28 women aged 57 +/- 11 yr; means +/- SD) and 34 age- and sex-matched healthy subjects were investigated by use of a one-step sandwich enzyme immunoassay, a new method developed by H.I. and others. As a screening, the patients were divided into three groups according to the first morning urinary concentrations of albumin: group 1, less than 30 micrograms/ml (normoalbuminuria); group 2, 30-140 micrograms/ml (microalbuminuria); group 3, greater than 140 micrograms/ml (clinical nephropathy). There was no significant difference in plasma TM level between the control group (17.7 +/- 3.7 ng/ml, n = 34) and group 1 (16.9 +/- 3.4 ng/ml, n = 30); however, plasma TM concentrations in group 2 (22.8 +/- 3.4 ng/ml, n = 22) and group 3 (29.6 +/- 6.1 ng/ml, n = 15) increased significantly compared with those in the control group and group 1, respectively. As a further investigation, three timed overnight urine collections were made. The patients were allocated to three groups according to their rates of albumin excretion: group I, less than 20 micrograms/min (normoalbuminuria); group II, 20-200 micrograms/min (microalbuminuria); group III greater than 200 micrograms/min (clinical nephropathy).(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes 1990 Aug
PMID:Elevation of plasma thrombomodulin level in diabetic patients with early diabetic nephropathy. 216 5

The effect of cyclosporin administered from 30 to 100 days of age on pancreatic events and the development of insulin-dependent diabetes has been studied by serial pancreatic biopsy of individual diabetes-prone BB/Edinburgh rats. Cyclosporin completely prevented the development of diabetes up to 150 days of age and reduced the incidence to 50% of controls at 452 days of age. Islet cell surface antibodies paralleled the development of diabetes. Insulin autoantibodies were unrelated to diabetes and not affected by cyclosporin. Immunohistochemical analysis of pancreatic biopsies from untreated control diabetes-prone rats with monoclonal antibodies specific for rat MHC molecules and T- and B-lymphocyte and macrophage subsets showed that the first abnormality seen in rats that subsequently developed diabetes was hyperexpression of MHC class I molecules on vascular endothelium and islet cells. This was followed by accumulation of ED1+ macrophages at perivascular and periductal sites adjacent to noninfiltrated islets. Increased expression of MHC class II molecules on vascular endothelial cells was also noted. Most cells infiltrating the islets initially were also ED1+ macrophages, followed by increasing numbers of other activated effector cells including helper and cytotoxic-suppressor T lymphocytes and natural killer cells. Obliteration of insulin-containing cells was associated with regression of the infiltrate. Treatment with cyclosporin had no effect on pancreatic hyperexpression of MHC class I molecules but markedly inhibited accumulation of ED1+ cells at extraislet sites, the subsequent recruitment of immune effector cells, and islet infiltration. This resulted in a delay of the onset of diabetes in some rats and prevention of diabetes in others.
Diabetes 1990 Apr
PMID:Effect of cyclosporin on pancreatic events and development of diabetes in BB/Edinburgh rats. 218 Jul 61

Autoregulation of blood flow denotes the intrinsic ability of an organ or a vascular bed to maintain a constant perfusion in the face of blood pressure changes. Alternatively, autoregulation can be defined in terms of vascular resistance changes or simply arteriolar caliber changes as blood pressure or perfusion pressure varies. While known in almost any vascular bed, autoregulation and its disturbance by disease has attracted particular attention in the cerebrovascular field. The basic mechanism of autoregulation of cerebral blood flow (CBF) is controversial. Most likely, the autoregulatory vessel caliber changes are mediated by an interplay between myogenic and metabolic mechanisms. Influence of perivascular nerves and most recently the vascular endothelium has also been the subject of intense investigation. CBF autoregulation typically operates between mean blood pressures of the order of 60 and 150 mm Hg. These limits are not entirely fixed but can be modulated by sympathetic nervous activity, the vascular renin-angiotensin system, and any factor (notably changes in arterial carbon dioxide tension) that decreases or increases CBF. Disease states of the brain may impair or abolish CBF autoregulation. Thus, autoregulation is lost in severe head injury or acute ischemic stroke, leaving surviving brain tissue unprotected against the potentially harmful effect of blood pressure changes. Likewise, autoregulation may be lost in the surroundings of a space-occupying brain lesion, be it a tumor or a hematoma. In many such disease states, autoregulation may be regained by hyperventilatory hypocapnia. Autoregulation may also be impaired in neonatal brain asphyxia and infections of the central nervous system, but appears to be intact in spreading depression and migraine, despite impairment of chemical and metabolic control of CBF. In chronic hypertension, the limits of autoregulation are shifted toward high blood pressure. Acute hypertensive encephalopathy, on the other hand, is thought to be due to autoregulatory failure at very high pressure. In long-term diabetes mellitus there may be chronic impairment of CBF autoregulation, probably due to diabetic microangiopathy.
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PMID:Cerebral autoregulation. 220 48

An increased platelet-vessel wall interaction plays an important role in most forms of cardiovascular disease. In healthy arteries, the vascular endothelium prevents platelet adhesion and aggregation. As a mediator of this protective function, the endothelium produces prostacyclin, endothelium-derived nitric oxide and tissue plasminogen activator. Cardiovascular risk factors such as hypertension, hyperlipidemia and diabetes are associated with an increased platelet activation and with decreased antithrombotic properties of the blood vessel wall. The available inhibitors of platelet function interfere only with one of various mechanisms of platelet activation and of the platelet-vessel wall interaction. Prostaglandin inhibitors, such as aspirin and newer, more specific inhibitors, prevent the production and/or the effect of thromboxane A2 on platelets and the blood vessel wall. Other drugs interfere with the effect of adenosine diphosphate on platelets, or they increase intracellular concentration of cyclic GMP or AMP in platelets and vascular smooth muscle cells. The protective effects of platelet inhibitors in primary and particularly in secondary prevention of cardiovascular diseases have been documented in numerous studies. The successful clinical use of these substances, however, requires a selective prescription of the drugs in patients with cardiovascular disease.
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PMID:[Thrombocyte inhibitors in cardiovascular therapy]. 221 49

Experiments on 5 test and 16 control Wistar-Kyoto rats have shown that streptozocin diabetes mellitus complicated by proteinuria is characterized by the following changes of the fatty acid spectrum of platelet phospholipids: a decrease in the content of C18:2p6, C18:3p3, C20:4p6, C20:3p9, C20:5p3, in the sum of fatty acids of the linoleic group and the ratio of unsaturated/saturated fatty acids and an increase in the content of C18:0, C20:2p6 and C20:3p6. These changes were accompanied by an increase in the platelet aggregation ability, an increase in their synthesis of thromboxane A2 and a decrease in the synthesis of prostacyclin I2 by vascular endothelium and account for them, to a certain degree. The obtained results are promising with relation to achieving a positive effect of the diets, rich in linoleic acid, for prophylaxis of vascular complications in diabetes mellitus.
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PMID:[Tha fatty acid spectrum of the thrombocyte phospholipids in experimental diabetes mellitus complicated by proteinuria]. 239 42

Endothelial cell functions regulating fetal hemodynamics and placental perfusion are modulated by metabolites of arachidonic acid, in particular derivatives of cyclooxygenase such as prostaglandins. We utilized an in vitro system to study the possible role of the vascular endothelium in the pathogenesis of chronic placental insufficiency. Cellular growth and prostaglandin metabolism were investigated in cultured umbilical vein endothelial cells from mothers exposed to risk factors such as smoking and diabetes mellitus during pregnancy. The study comprised cells from smoking (n = 18) and diabetic mothers (n = 5) compared to non-smoking, non-diabetic controls (n = 20). Endothelial cells from smoking and diabetic mothers grew less readily than did control cells. The synthesis of the prostaglandins PGI2 and PGE2, both potent vasodilators and platelet aggregation inhibitors, was significantly reduced in endothelial cells from smoking mothers and from mothers suffering from diabetes of various stages. Thus, reduced prostaglandin synthesis may be a cause of impaired placental perfusion in high risk pregnancies. Our data suggest that prostaglandins may play an important role in the etiology and pathogenesis of chronic placental insufficiency.
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PMID:[Functional differentiation of the vascular endothelium in high risk pregnancies]. 249 34

The recent discovery of endothelium-derived relaxation factor (EDRF) has altered the traditional classification of vasodilators used in angina pectoris and heart failure. If a vasodilator induces release of EDRF from the epithelium it is classified as endothelium-dependent, if not it is independent. Sodium nitroprusside and SIN-1 (active metabolite of molsidomine) are the main independent vasodilators since the endothelium relaxation factor appears to be principally a nitric oxide radical in these synthetic vasodilators. In contrast, calcium-channel blockers and a good number of endogenous chemical mediators (acetylcholine, bradykinin, serotonin, etc.) are endothelium-dependent. Furthermore, simple increase in blood flow through the large vessels can result in endothelium-dependent vasodilation (flow rate-dependence) the extent of which depends on the drug examined. The fact that the pharmacologic response of a vasodilator can be altered under certain pathologic conditions (atherosclerosis, hypertension, diabetes, etc.) further increases the importance of the role of the vascular endothelium in the action of vasodilators since endothelial modulation may then be completely diverted to secretion of endothelium-derived contracting factors (EDCFS).
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PMID:[Vasodilator agents and the vascular endothelium]. 262 13

Streptozotocin-induced diabetes caused an increase in AP and reactivity to noradrenaline in perfused caudal artery of normotensive rats (WKY). In spontaneously hypertensive rats (SHR) diabetes led to an increase in reactivity not only to noradrenaline but also to alpha 1-agonist phenylephrine; a response to endothelium-dependent agent acetylcholine was decreased. Alterations in function of the vascular endothelium may be one of the factors causing elevation of vasoconstriction in diabetes mellitus.
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PMID:[The vascular response of spontaneously hypertensive and normotensive rats with diabetes mellitus]. 271 81


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