Water distribution in insulin-dependent diabetes mellitus in various states of metabolic control.

Alterations in water compartments have been described in insulin-dependent diabetes mellitus (IDDM). Both insulin and lack of natriuretic counteracting response lead to water expansion, while hyperglycemica-induced osmotic diuresis leads to water depletion. Both total body water and water distribution in the extra-intracellular space, as well as their relationships to metabolic control, were investigated in 15 controls (30.

Hypertension and non-insulin-dependent diabetes. A comparison between an angiotensin-converting enzyme inhibitor and a calcium antagonist.

The effects of the angiotensin-converting enzyme lisinopril were compared with those of the calcium antagonist nifedipine in 162 non-insulin-dependent diabetic hypertensive patients for a 24-week period. In 83 and 79 patients, respectively, lisinopril and slow-release nifedipine produced similar reductions in blood pressure (systolic/diastolic: -16/-13 mmHg supine and -14/-11 mmHg standing after lisinopril; -15/-12 mmHg supine and -14/-11 mmHg standing nifedipine). Fasting and post-prandial plasma glucose, glycosylated haemoglobin and plasma lipids appeared to be unaffected by either agent.

An instrument for real-time spectral estimation of heart rate variability signals.

A Digital Signal Processor (DSP)-based instrument is proposed for estimating and displaying the Heart Rate Variability (HRV) spectrum in real-time. It consists of an intelligent module which is properly interfaced to an IBM PC and whose operations are independent from the computer's other tasks. In this way, the simultaneous recording of the ECG sequence, needed for the more complete off-line analysis, can be performed by the same host.

Impairment of central motor conduction in diabetic patients.

In 70 patients with diabetes mellitus (DM) we recorded the motor evoked potentials (MEPs) following magnetic stimulation of the motor cortex and spinal roots. Central motor conduction time (CMCT) was determined as the difference between MEP latencies after cortical and spinal stimulation. The mean CMCTs for the biceps, thenar and tibialis anterior muscles were prolonged in the DM group, as compared to normal controls, and 21 patients exceeded the CMCT upper confidence limit for at least one muscle.

Increased expression of tissue plasminogen activator and its inhibitor and reduced fibrinolytic potential of human endothelial cells cultured in elevated glucose.

In diabetic patients, elevated plasma levels of t-PA and PAI-1 accompany impaired fibrinolysis. To identify mechanisms for these abnormalities, we examined whether vascular endothelial cells exposed to high glucose upregulate t-PA and PAI-1 production and whether ambient PA activity is decreased concomitantly. In 17 cultures of human umbilical vein endothelial cells grown to confluency in 30 mM glucose, the t-PA antigen released to the medium in 24 h was (median) 52 ng/10(6) cells (range 10-384) and the PAI-1 antigen was 872 ng/10(6) cells (range 217-2074)--both greater (P less than 0.

Isolation of pig pancreatic islets by a new method with hydraulic shaking: preliminary report.

The limited availability of human pancreas represents a serious problem in islet transplantation. In the past few years many efforts have been made to isolate pancreatic islets from large mammals in order to achieve valid and reproducible isolation methods. For several reasons swine may be considered an ideal source of islet tissue because of the similarity between human and porcine insulin and because of the easy availability of pig pancreata.

Comparison of the effects of carvedilol and nifedipine in patients with essential hypertension and non-insulin-dependent diabetes mellitus.

The safety and tolerability of carvedilol, a new antihypertensive agent with the combined pharmacological activities of beta-blockade and vasodilation, and of nifedipine were investigated in patients with essential hypertension and non-insulin-dependent (type II) diabetes mellitus. Twenty patients were openly randomized to receive 25 mg carvedilol once daily (five men and five women; mean age, 63 years) or 10 mg nifedipine t.i.

Malondialdehyde (MDA) level in diabetic subjects. Relationship with blood glucose and glycosylated hemoglobin.

The relationships between plasma malondialdehyde (MDA) and metabolic parameters in type I and II diabetic subjects have been studied at different levels of glycemic control. In 67 diabetics (20 type I, 47 type II, aged 53 +/- 1.2) and 40 healthy subjects (aged 47 +/- 1.

Prevention of diabetes-increased aging effect on rat collagen-linked fluorescence by aminoguanidine and rutin.

Products from the advanced Maillard reaction, which increase during aging and diabetes, may contribute to the development of the typical pathology of aging and diabetes. These compounds are detectable only by their characteristic fluorescence, and few data based on long-term studies are available. For this reason, we studied subcutaneous skin collagen fluorescence in 57 nondiabetic (10- to 110-wk-old) and 74 streptozocin-induced diabetic (10- to 22-wk-old) rats.

Antipeptide antibodies toward the extracellular domain of insulin receptor beta-subunit.

In order to investigate structure and function of beta-subunit extracellular portion, four polyclonal antibodies (AP1, AP2, AP3 and AP4) toward peptides comprised in this region were generated. None of them recognizes native human and rat insulin receptor both in vitro and in whole cells. Two antibodies, AP1 and AP2, immunoprecipitate isolated (DTT-reduced) human beta-subunits and bind to human IM-9 cell after alpha-subunit tryptic cleavage.

[Insulin secretion and hepatic extraction in juvenile non-insulin-dependent diabetes].

Beta-cell secretion is still a point of controversy. As the liver is the major site of insulin metabolism, evaluation of hepatic insulin extraction is crucial for correct measurement of beta-cell secretion. Methods for calculating the secretion and hepatic extraction of insulin indirectly from peripheral C-peptide concentration have been proposed by some investigators.

An extracellular domain of the insulin receptor beta-subunit with regulatory function on protein-tyrosine kinase.

Anti-insulin receptor monoclonal antibody MA-10 inhibits insulin receptor autophosphorylation of purified rat liver insulin receptors without affecting insulin binding (Cordera, R., Andraghetti, G., Gherzi, R.

Effect of two different glucose concentrations on insulin receptor mRNA levels in human hepatoma HepG2 cells.

Glucose is known to affect mRNA levels of several genes. In order to investigate possible effects of glucose on insulin receptor mRNA levels, we cultured human hepatoma cells (HepG2) in two different culture media: DMEM containing 100 mg/dl glucose and DMEM containing 450 mg/dl glucose. Insulin receptor mRNA levels and insulin binding activity were reduced in HepG2 cultured at lower glucose concentrations.

Platelet and clotting activities after cold stress in diabetic patients.

Platelet and clotting abnormalities have been described in diabetes, but little is known about their relationship to daily stresses. In order to evaluate whether states of abnormal carbohydrate metabolism modify the hemostatic response to stress, 12 subjects with type I diabetes mellitus, 9 with type II, 7 with impaired glucose tolerance and 10 healthy controls were exposed to a cold pressor test. Plasma concentrations of beta-thromboglobulin (index of platelet activation) and of fibrinopeptide A (index of thrombin formation) were measured before and 15 minutes after forearm immersion in melting ice.

Species specificity of insulin binding and insulin receptor protein tyrosine kinase activity.

The effect of monoclonal anti-insulin receptor antibody MA 10 on [125I]insulin binding and on insulin receptor protein tyrosine kinase activity was investigated in human and rat tissues. It was observed that MA 10 inhibits insulin binding to human, but not rat, tissues while inhibiting insulin-stimulated receptor autophosphorylation and protein tyrosine kinase activity in both human and rat tissues. These data suggest that MA 10 is directed against a region of the insulin receptor that is in between the insulin-binding domain and the beta-subunit and that in human, but not rat, tissues, this region is involved in insulin binding.

Regulation of insulin receptor-associated tyrosine kinase by a polyclonal IgG.

The effect of a polyclonal anti-insulin receptor antibody (pIgG) on the insulin receptor tyrosine kinase (IRTK) activity toward poly-(Glu-Tyr) was examined using wheat germ agglutinin agarose-purified insulin receptors from rat liver membranes. The main effect of pIgG was a reduction of Vmax (from 60.8 to 31.

Insulin-like growth factor I (IGF I) receptor autophosphorylation and kinase activity. Effect of a human polyclonal antibody (pIgG).

IGF I receptor is a tyrosine kinase capable of phosphorylating the receptor itself and other substrates. A high degree of homology does exist in tyrosine kinase domain among receptors for several polypeptide growth factor receptors and this enzymic activity has been indicated as a possible mediator of biological action. Nevertheless growth factor receptors possess peculiar specificities both in their functions and tissue distribution.

[Left ventricular diastolic function in type I diabetes. A longitudinal echocardiographic study].

The present study was performed to assess the extent of left ventricular diastolic abnormalities and their possible progression with time in patients with type I (insulin dependent) diabetes. Two echocardiographic examinations were performed at an interval of 5 years in 18 study patients. Left ventricular diastolic function was assessed by computer digitized analysis of the M-mode echocardiographic tracings.