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Biomedical subjects

G Riccardi

Publications and source records attributed to G Riccardi.

At least 163 records · Page 9Linked to original sources
PubMed1985

Plasma lipoproteins and lipoprotein lipase in young diabetics with and without ketonuria.

Plasma lipoprotein and lipoprotein lipase activity have been evaluated in young diabetics with and without ketonuria and in healthy controls of the same age. Fifteen (age range 7-23 years) newly detected diabetics (8 with ketonuria, 7 non ketonuric) have been examined before starting the treatment. Five healthy medical students (age range 19-21 years) have also been studied. Both ketotic and non ketotic patients showed an impaired insulin and C-peptide response to the glucose load in comparison to controls. Ketotic patients had low lipoprotein lipase activity (p less than 0.01) and high density lipoprotein (p less than 0.01); total plasma Triglycerides and VLDL Triglyceride and Cholesterol were higher than in controls. Plasma Triglyceride and VLDL Triglyceride and Cholesterol were inversely related to lipoprotein lipase activity. Low lipoprotein lipase activity, from adipose tissue and muscle, has been found to be associated with hypertriglyceridemia and reduced HDL Cholesterol in young diabetic patients with ketonuria.

Adolescent↗
PubMed1985

Reproducibility of the new diagnostic criteria for impaired glucose tolerance.

Sixty-seven subjects with impaired glucose tolerance and 136 normoglycemic individuals defined according to the diagnostic criteria of the European Association for the Study of Diabetes were selected from among persons aged 40-59 years who participated in a health examination survey in Naples in 1980. A second oral glucose tolerance test was given under identical conditions between two and four months later with the participants having no knowledge of the results of the first test. Venous whole blood was utilized for blood glucose determination. At the second test, 93% of the control group were confirmed to be normoglycemic, but only 56% of the impaired glucose tolerance group were still intolerant. Reproducibility was poorest among subjects with blood glucose two hours after load of less than 140 mg/dl. Among these subjects, 47% reverted to normoglycemia at the second test. In contrast, 15% of those with blood glucose greater than or equal to 140 mg/dl two hours after load reverted to normoglycemia (chi 2 = 6.29, p less than 0.05). Subjects with impairment of glucose tolerance at the second test were reclassified according to the diagnostic criteria of the National Diabetes Data Group and the World Health Organization (WHO). Only 22 (46%) of the 48 individuals classified in the impaired glucose tolerance group according to the criteria of the European Association for the Study of Diabetes were so classified by the criteria of both the National Diabetes Data Group and WHO. The disagreement between the three diagnostic criteria was maximal in the lowest blood glucose range. It is concluded that the diagnosis of impaired glucose tolerance, despite the new diagnostic criteria, still has little reproducibility and uniformity.

Adult↗
PubMed1985

Different glycaemic responses to pasta, bread, and potatoes in diabetic patients.

To evaluate whether the same amount of carbohydrate (CHO) in different foods gives different glycaemic responses when consumed in the context of a real meal, seven diabetic patients were given in a random order and on alternate days three test meals of identical composition. Each meal consisted of a fixed part to which a 50 g CHO portion of either bread (90 g) or spaghetti (65 g) or potatoes (285 g) was added. The glycaemic response was significantly higher after ingestion of bread than after the spaghetti meal both at 2 (5.9 +/- 0.8 vs 4.3 +/- 0.7 mmol/l X hour, p less than 0.05) and at 5 hours (16.5 +/- 3.6 vs 9.8 +/- 2.3 mmol/l X hour, p less than 0.05). The glycaemic response to the potato meal was similar to that for bread at 2 hours (6.2 +/- 1.2 mmol/l X hour, p less than 0.05 vs spaghetti) and intermediate between the two other test meals at 5 hours (14.6 +/- 4.3 mmol/l X hour). Meal planning for diabetic patients should be based not only on the biochemical properties but also on the glycaemic response to the food.

Blood Glucose↗
PubMed1985

Association between low habitual physical activity and impaired glucose tolerance.

The aim of this study was to evaluate whether a relationship exists between impaired glucose tolerance and both habitual physical activity and physical working capacity. Sixty-five apparently healthy subjects with impaired glucose tolerance (according to criteria of the European Association for the Study of Diabetes), age range 40-59 years, and 125 subjects with normal tolerance, sex, age and body mass index matched, were selected among the participants in a health examination survey. They filled in a questionnaire on daily physical activity during work and leisure time and performed an exercise test on a cyclergometer. No difference in physical activity at work was recorded between the groups, but the proportion of individuals who were physically active during leisure time, was significantly lower among the subjects with impaired glucose tolerance (8.1% vs 19.7%; P less than 0.05). Moreover these subjects had a higher heart rate during and 1 min after the standard exercise test (113.4 +/- 15.8 vs 105.7 +/- 17.7 beats/min, P less than 0.005; mean +/- SD). This supports the hypothesis that low physical activity is a risk factor for impaired glucose tolerance, independent of mutual effect of obesity.

Blood Glucose↗
PubMed1985

Increased binding of fibrinogen to platelets in diabetes: the role of prostaglandins and thromboxane.

Previous studies suggested a role for prostaglandins or thromboxane A2, or both in the exposure of fibrinogen receptors on normal platelets in response to several aggregating agents. Platelets from diabetics are known to be more sensitive to aggregating agents and to produce more prostaglandins and thromboxane than platelets from normal subjects. We compared fibrinogen binding to platelets from diabetic subjects with binding to platelets from normal subjects and determined whether aspirin (which inhibits the formation of prostaglandins and thromboxane) would inhibit the binding of fibrinogen to platelets from diabetic subjects and whether this correlated with its effects on platelet aggregation. We found the following: Aspirin suppressed thromboxane formation and rendered the platelets less sensitive to the induction of aggregation by adenosine diphosphate (ADP) or collagen. The amount of U-46619 [( 15s]-hydroxy-11-alpha, 9-alpha [epoxy-methano]-prosta[5Z,13E]-dienoic acid, a stable analog of prostaglandin endoperoxide/thromboxane A2) necessary to induce aggregation, was similar in normal and diabetic subjects and was unchanged after ingestion of aspirin. Binding of 125I-fibrinogen following stimulation of platelets by ADP or collagen was greater in diabetic (because more binding sites were exposed) than in normal subjects. However, following stimulation by U-46619, binding was similar in diabetic and normal subjects. Aspirin caused a reduction in the exposure of binding sites on both platelets from diabetic and normal subjects, so that (in this respect) platelets from diabetic subjects became more like those from normal subjects. Effects of the monoclonal antibody B59.2, which is specific for the platelet glycoprotein IIb-IIIa complex (the presumed receptor for fibrinogen on the platelet surface) were also studied. The amount of this antibody that bound to platelets was the same for normal and diabetic subjects both before and after aspirin and with or without stimulation by ADP or collagen. In addition, B59.2 inhibited aggregation and fibrinogen binding in both platelets from diabetic and normal subjects. The combined data suggest that the glycoprotein IIb-IIIa complex of platelets from diabetic subjects is similar to that of platelets from normal subjects and that the increased fibrinogen binding and aggregation of platelets from diabetic subjects in response to ADP or collagen is mediated by increased formation of prostaglandin endoperoxide or thromboxane A2, or both.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1985

Relationship between insulin response to intravenous glucose and plasma lipoproteins in healthy men.

In order to evaluate the influence of serum insulin levels on serum lipoprotein composition, 62 randomly selected healthy males were studied. All of them had a normal glucose tolerance. The Insulin Response to a bolus of intravenous glucose (0.50 g/kg) was significantly correlated with VLDL-Triglyceride (p less than 0.01), VLDL-Cholesterol (p less than 0.01) and with the "Atherogenic Index" (Formula: see text) (p less than 0.01). Moreover, stratifing the all population in quartiles according to the Insulin Response distribution, the highest quartile had a significant increase in Total and VLDL-Cholesterol levels (p less than 0.02), as well as in Total (p less than 0.02), VLDL (p less than 0.02) and LDL (p less than 0.01) Triglyceride, in comparison with the lowest quartile. The Atherogenic Index was also significantly elevated in the high Insulin Response group (p less than 0.005). The influence of serum insulin on lipoprotein metabolism was also evaluated by a stepwise multiple regression analysis. Body weight, Insulin Response and Exogenous Triglyceride removal were independently correlated with VLDL-Triglyceride concentration (r = 0.58, p less than 0.001). VLDL cholesterol concentration and fasting serum insulin levels were inversely correlated with HDL-Cholesterol (r = 0.49, p less than 0.001). In conclusion, in absence of any metabolic derangement, high insulin levels are associated with multiple lipoprotein abnormalities. Insulin might act as a risk factor for arterial disease through its influence on serum lipoproteins.

Adult↗
PubMed1984

Separate influence of dietary carbohydrate and fibre on the metabolic control in diabetes.

To clarify the separate influences of digestible carbohydrate and of dietary fibre on blood glucose control and serum lipoproteins, 14 diabetic patients (six Type 1 and eight Type 2) were submitted to three weight-maintaining diets for 10 days each: (1) low carbohydrate/low fibre diet with 42% carbohydrate and 20 g fibre; (2) high carbohydrate/low fibre diet (carbohydrate 53%, fibre 16 g); (3) high carbohydrate/ high fibre diet (carbohydrate 53%, fibre 54 g). In comparison with the low carbohydrate/low fibre diet, the 2-h post-prandial blood glucose and the daily blood glucose profile decreased significantly on the high carbohydrate/high fibre diet, without significant changes during the high carbohydrate/low fibre diet. The diet-induced modifications of blood glucose control were similar in both types of diabetic patients (two-way analysis of variance: F = 5.86, p less than 0.02 for dietary treatment and F = 2.09, NS for type of diabetes). Total and low-density lipoprotein cholesterol were also decreased after the high carbohydrate/high fibre diet in comparison with the low carbohydrate/low fibre diet (p less than 0.001 for both), while they were not significantly modified after the high carbohydrate/low fibre diet. Again the modifications of low density lipoprotein cholesterol induced by diet were similar in both types of diabetic patients (F = 10.02, p less than 0.005 for dietary treatment and F = 0.14 for type of diabetes, NS). High-density lipoprotein cholesterol was lower after the two test diets than after the low carbohydrate/low fibre diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1982

Altered methionyl-tRNA synthetase in a Spirulina platensis mutant resistant to ethionine.

Compared with the parental strain, a Spirulina platensis mutant that is resistant to ethionine incorporated methionine into protein at a reduced rate, whereas ethionine incorporation was practically nil. The methionyl-tRNA synthetase present in crude extracts from the resistant strain showed a reduced affinity for methionine and ethionine.

Amino Acyl-tRNA Synthetases↗
PubMed1982

Risk factors for peripheral atherosclerosis in non insulin dependent diabetes.

Peripheral Atherosclerosis (PA) is a frequent complication of longstanding diabetes. Nevertheless uncertainty exists on defining risk factors (RF) for PA in diabetics. In order to elucidate this matter, at an early stage of the vascular complication, 54 non insulin dependent diabetic (NIDDM) patients, males, age range 40-59 years, without clinical signs of PA, were investigated by digital pulse plethysmography, measuring the inclination time (IT) of the pulse wave. A significant correlation was found between systolic blood pressure (BP) or fasting serum cholesterol (FSC) and IT (r = .28 p less than .05 and r = .34 p less than .05). IT was significantly higher in insulin treated patients compared with those on oral hypoglycemic treatment (154 +/- 41 msec; 122 +/- 25 msec; p less than .05) (M +/- SD). No significant effect on IT was induced by body weight, diastolic BP, serum triglycerides. A positive correlation was found between the number of RF (FSC greater than or equal to 220 mg/dl; systolic BP greater than or equal to 160 mmHg; insulin treatment) in each patient and IT (r = .55 p less than .001). In the absence of RF, IT was similar to that in non diabetic, normocholesterolemic, normotensive men of the same age (119 +/- 27; 116 +/- 15). FSC, systolic BP and insulin treatment are major RF for PA in male NIDDM patients. The condition is worsened by the simultaneous presence of two or more RF together.

Adult↗
PubMed1981

Production of amino acids by analog-resistant mutants of the cyanobacterium Spirulina platensis.

Mutants of Spirulina platensis resistant to 5-fluorotryptophan, beta-3-thienyl-alanine, ethionine, p-fluorophenylalanine, or azetidine-2-carboxylic acid were isolated. Some of these mutants appeared to be resistant to more than one analog and to overproduce the corresponding amino acids. A second group was composed of mutants that were resistant to one analog only. Of the latter mutants, one resistant to azetidine-2-carboxylic acid was found to overproduce proline only, whereas one resistant to fluorotryptophan and one resistant to ethionine did not overproduce any of the tested amino acids.

Alanine↗
PubMed1980

Effect of dietary fibre on glucose control and serum lipoproteins in diabetic patients.

To evaluate the effects of a fibre-rich diet on blood glucose and serum lipoproteins, eight diabetic patients, four on insulin and four on oral hypoglycaemic drugs, were put on three different diets, a different one for each consecutive 10-day period: diet A (carbohydrate 53%, fibre 16 g), diet B (carbohydrate 53%, fibre 54 g), and diet C (carbohydrate 42%, fibre 20 g). All diets had identical polyunsaturated/saturated fat ratios. Both 2 h post-prandial glucose and mean daily glucose levels were significantly lower after diet B than after either of the two other diets, as were total and LDL cholesterol levels. Total and VLDL triglyceride levels after diet B were significantly lower than those after diet A but almost identical to those after diet C. HDL cholesterol concentration was not affected by dietary fibre but was significantly increased by the low-carbohydrate diet. A high-fibre, normal-carbohydrate diet (the fibre coming exclusively from foodstuffs with a naturally high content of fibre) improves blood glucose control and decreases the concentration of atherogenic lipoproteins in diabetic patients. This effect is independent of the amount of available carbohydrates in the diet.

Adult↗
PubMed1980

Plasma high density lipoprotein in severe obesity after stable weight loss.

Changes in plasma lipoprotein pattern, with particular attention to high density lipoprotein cholesterol (HDL-C) concentration, were evaluated in 7 (5 female, 2 male) obese patients before and 15 +/- 1 months after they had lost weight (mean 20.7 +/- 3.1 kg), when the patients' food intake had been ad libitum for at least 6 months, and they had been maintaining their weight loss. Plasma low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein triglyceride (VLDL-TG) concentrations were lower than baseline values: on the other hand, plasma HDL-C concentration, which was below normal values before weight reduction, was found to be significantly increased (P < 0.05). These data indicate that, among the favourable changes in plasma lipoprotein pattern, an increase in HDL-C may be achieved after remarkable and stable weight loss in severe obesity.

Adult↗
PubMed1980

Plasma lipoproteins in maturity onset diabetes.

Plasma lipoprotein abnormalities in maturity onset diabetes (MOD) reflect both enhanced production and impaired removal of triglyceride-rich lipoproteins. Hyperglycemia and hyperinsulinemia lead to overproduction of very-low density lipoproteins by the liver. Fat tolerance is reduced in MOD patients: this might be due to low lipoprotein lipase activity (LLA) and/or to low incorporation of LLA-released fatty acids into adipose tissue glyceride. This finding of abnormal low-density lipoprotein composition, with relative enrichment in triglyceride, suggests remnant particle accumulation.

Adult↗
PubMed1979

[Glucose tolerance and insulinemia in patients with hepatic cirrhosis and portal hypertension treated by portacaval anastomosis].

Development of diabetes mellitus is a common complication of side to side porta-caval anastomosis (PCA). Five patients with liver cirrhosis and portal hypertension have been studied with intravehous (IVGTT, 0,5 g/Kg B.W.) and oral (OGTT, 1 g/Kg B.W.) glucose tolerance tests before and three weeks after PCA. Fasting plasma glucose was 84 +/- 7 before and 87 +/- 3 mg/dl after PCA. Fasting IRI increased from 17 +/- 3 to 31 +/- 6 microU/ml. The pattern of plasma glucose and IRI response to IVGTT did not change after PCA. Plasma glucose resonse to OGTT after PCA showed only an earlier rise at 60 instead of 90 minutes, whereas IRI resonse (area under the insulin curve) was significantly enhanced (from 12.4 to 19.8 U/l, p < 0.05). These data suggest a role of gut polipeptides in determining hyperinsulinemia and insulin resistence in PCA patients.

Adult↗
PubMed1979

Insulin and substrate exchange in the forearm during prolonged forearm work.

Forearm exchange of insulin and uptake of oxygen, glucose and free fatty acids (FFA) were studied during 120 min forearm work in six healthy male volunteers. At rest the arterial-deep venous difference of insulin was zero. At the onset of work release of insulin occurred, which continued at constant rate throughout the work despite unaltered arterial insulin concentration. Extractions of oxygen, glucose and FFA were of similar magnitudes at 120 as at 15 min work, while lactate release decreased with time. It is concluded that (1) a significant insulin release from muscle tissue or its vascular bed occurs and continues at undiminished rate during prolonged work, (2) a substantial amount must be bound in the tissue, unless local synthesis takes place and (3) despite this loss of insulin from the forearm no major change in glucose and FFA extraction occurs with duration of work.

Adult↗