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Biomedical subjects

E Manzato

Publications and source records attributed to E Manzato.

At least 37 records · Page 2Linked to original sources
PubMed1996

Short-term diabetic ketosis alters n-6 polyunsaturated fatty acid content in plasma phospholipids.

At present, no information is available about the possibility that acute loss of metabolic control might be able to modify fatty acid composition in IDDM patients. Therefore, the aim of this study was to determine whether a short-term period of ketosis has any effect on the composition of fatty acid of plasma phospholipids in a group of insulin-dependent diabetes mellitus (IDDM) patients. Eleven IDDM patients and nine healthy volunteers were studied. Patients were studied over a 2-day period; each 2-day period consisted of initial baseline measurements followed by a day of hyperglycemia and mild ketosis, which was promptly alleviated by insulin infusion. No significant difference in baseline percent fatty acid composition was observed between normal controls and IDDM patients. In IDDM patients, ketosis induced a significant decrease in percent arachidonic acid (20:4 n-6) content, with a significant parallel decline in n-6 total polyunsaturated fatty acids. A significant inverse correlation between the prevailing plasma glucose and the relative content of arachidonic acid in plasma phospholipids was observed (r = -0.35; P = 0.0488). A highly significant inverse correlation was observed between the change from baseline condition to ketosis of the ratio C20:4/C20:3, the product/precursor ratio for the reaction catalyzed by delta5-desaturase, and the values of hemoglobin A1c,(r = -0.855; P = 0.0015). In conclusion, short term diabetic ketosis is associated with a significant decrease in n-6 polyunsaturated fatty acid content in plasma phospholipids, especially arachidonic acid. This decrease in arachidonic acid appears to be related to the degree of metabolic derangement, whereas the influence of short-term diabetic ketosis on the ratio of C20:4 to C20:3 seems to be due to the degree of long-term metabolic control.

Adult↗
PubMed1996

Anomalous phospholipid n-6 polyunsaturated fatty acid composition in idiopathic calcium nephrolithiasis.

Anomalies in the erythrocyte transport of anions and cations have been described in idiopathic calcium oxalate nephrolithiasis and seem to play a pathogenetic role in this disease. In consideration of the hypothesis that the complex array of ion flux cell abnormalities is an epiphenomenon of an anomaly in the composition of cell membranes, this study investigated cell-membrane lipid composition. In idiopathic calcium oxalate renal stone formers, in which ion transport abnormalities were present, and in healthy control subjects, plasma and erythrocyte membrane lipid composition, the erythrocyte oxalate exchange, and Na/K/2Cl cotransport activity were evaluated. Furthermore, in stone formers, the effect of a 30-day fish-oil diet supplementation on plasma lipids, erythrocyte oxalate exchange, oxaluria, and calciuria was investigated. The effect of archidonic acid released by phospholipase A2 on anion-carrier phosphorylation and activity in erythrocytes was evaluated as well. Patients had a lower content of linoleic and higher concentration of archidonic acids in both plasma and erythrocyte membrane phospholipids, and an increased archidonic/linoleic acid ratio. The archidonic acid level correlated with the erythrocyte oxalate exchange and sodium cotransport activity. Fish-oil supplementation lowered calcium and oxalate urine excretion, and normalized the erythrocyte oxalate exchange. Phospholipase A2 increased the erythrocyte anion-carrier protein phosphorylation and the oxalate exchange. This study shows that idiopathic calcium nephrolithiasis in the patient group reported here is characterized by a systemic defect in phospholipid archidonic acid levels that might provide an answer to the link between genetic background, dietary habits, and renal lithiasis.

Adult↗
PubMed1996

[Progress in hypocholesterolemic therapy in the prevention of recurrent infarction].

The role of the hypocholesterolemic therapy in reinfarction prevention is evaluated using data from observational and secondary prevention studies. Even though survival after myocardial infarction is largely determined by the extension of the necrotic lesion, hypercholesterolemia remains an important risk factor for new vascular events. A total cholesterol reduction < 200 mg/dL (or even better LDL cholesterol < 100 mg/dL) in these patients is associated within few years with a significant reduction of both clinical events and total mortality. The reduction of clinical events is obtained in a relatively short period of time thus suggesting that plasma cholesterol reduction induces quite rapidly some modifications of the natural history of the atherosclerotic plaques, this effect being more relevant in vulnerable or unstable lesions that are responsible for most of the clinical events. These observations show that after myocardial infarction it is useful to reduce cholesterol < 200 mg/dL also with the use of drugs.

Anticholesteremic Agents↗
PubMed1995

Insulin action and glucose metabolism are improved by gemfibrozil treatment in hypertriglyceridemic patients.

The aim of this study was to determine whether gemfibrozil-mediated decrease in very low density lipoprotein triglyceride (VLDL-TG) concentration is accompanied by an improvement in overall glucose metabolism in hypertriglyceridemic patients. We assessed this hypothesis in 7 hypertriglyceridemic without (HTG) and in 11 hypertriglyceridemic with noninsulin-dependent diabetes mellitus (NIDDM-HTG) who followed three-months treatment either with the drug or with placebo. Placebo VLDL-TG concentrations in both HTG (3.82 +/- 0.92 mmol/l (mean +/- S.D.) vs. 3.91 +/- 1.01 mmol/l) and in NIDDM-HTG (6.62 +/- 3.93 mmol/l vs. 6.84 +/- 4.16 mmol/l) were not different from baseline values, whereas gemfibrozil decreased VLDL-TG in both groups (1.84 +/- 0.56 mmol/l, P < 0.001 for HTG, and 1.93 +/- 2.68 mmol/l, P = 0.013 in NIDDM-HTG). In both groups, gemfibrozil treatment was associated with an improvement in fasting plasma glucose levels (from 5.85 +/- 0.92 mmol/l to 4.87 +/- 0.40 mmol/l in HTG, P = 0.001, and from 11.47 +/- 2.92 mmol/l to 9.56 +/- 3.41 mmol/l in NIDDM-HTG, P = 0.042). In NIDDM-HTG, gemfibrozil treatment was associated with a significantly lower 2 h-postprandial plasma glucose level (9.87 +/- 3.63 vs. 13.09 +/- 3.62, P = 0.05). A significant decrease in fasting free fatty acids (FFA) level was observed during gemfibrozil treatment in both groups, whereas in NIDDM-HTG, a significant drop of these substrates was observed in both fasting and postprandial conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗
PubMed1995

The lipoprotein composition of plasma and ascitic fluid in liver cirrhosis.

Lipoprotein particles were examined in plasma and ascitic fluid from nine patients (5 males and 4 females) with liver cirrhosis and in plasma from nine control subjects. LDL and HDL fractions were isolated by ultracentrifugation under rate flotation conditions in a zonal rotor. LDL size was analysed by non-denaturing polyacrylamide gradient gel electrophoresis. Plasma lipids in cirrhotic patients were markedly reduced compared to controls. Free cholesterol represented 45.3% of the total cholesterol in plasma and 70.4% of the total cholesterol in the ascitic fluid. The total cholesterol-triglyceride ratio was three times higher in the plasma than in the ascitic fluid of cirrhotic patients. The LDL particles had the same flotation properties in plasma from cirrhotic patients as in that from controls. In cirrhotic patients the IDL concentration was higher than that in controls. In ascitic fluid the LDL particles had a higher flotation rate than in the plasma. The LDL diameter as measured by gradient gel electrophoresis was similar in both plasma and ascitic fluid of the cirrhotic patients as well as in the plasma of controls. In plasma and ascitic fluid of cirrhotic patients only a single HDL subclass (HDL1) could be identified. HDL1 particles had a higher flotation rate than normal HDL particles. The plasma levels of all the apoproteins were reduced in cirrhotic subjects compared to controls, but to a variable degree; while apo CII level in cirrhosis represented only 9% of the control level, the apo E level represented 77% of the control level.(ABSTRACT TRUNCATED AT 250 WORDS)

Ascites↗
PubMed1994

Pravastatin treatment in combined hyperlipidaemia. Effect on plasma lipoprotein levels and size.

Combined hyperlipidaemia and the presence of small and dense LDL particles in the circulation are associated with an increased risk of myocardial infarction. The effect of pravastatin on plasma lipoproteins and on LDL size has been evaluated in a single-blind, randomised, placebo-controlled study in 24 patients with combined hyperlipidaemia; 12 patients on pravastatin and 12 on placebo. After 16 weeks on pravastatin, plasma total (-15%) and LDL (-23%) cholesterol and apo B (-13%) levels were significantly reduced and apo AI (+6%) had increased. LDL size (measured by gradient gel electrophoresis) had not changed. No adverse effect was observed. The study suggests that, in combined hyperlipidaemia, LDL size is not affected by variation in LDL receptor activity.

Adult↗
PubMed1994

Peripheral, rather than hepatic, insulin resistance and atherogenic lipoprotein phenotype predict cardiovascular complications in NIDDM.

Microalbuminuria, hypertension and hyperinsulinaemia are three independent risk factors for cardiac disease in non insulin-dependent diabetes (NIDDM). However, it is unknown to what extent hyperinsulinaemia reflects resistance to insulin action at hepatic, extrahepatic or at both sites. A cross-sectional study from our Department showed that peripheral insulin resistance, hypertension, microalbuminuria and lipid abnormalities are associated in NIDDM. Non diabetic individuals with the so-called 'atherogenic lipoprotein phenotype', characterized by small dense low density lipoproteins (LDL subclass pattern B) have up to 3-fold higher risk of myocardial infarction. The aim of the present study was to investigate whether impaired peripheral insulin sensitivity, during euglycaemic-hyperinsulinaemic clamp, as well as abnormalities in lipid concentrations and LDL size, predict abnormalities in albumin excretion rate, blood pressure and cardiac function in 73 consecutive normotensive (< 85 mmHg diastolic level) and normoalbuminuric (< 15 micrograms min-1 daily albumin excretion rate) NIDDM patients. These patients showed a bimodal distribution of whole body glucose utilization rate, a parameter of peripheral insulin sensitivity. The cut-off point between the two modes of distribution was located close to the mean value minus one standard deviation in a population of 24 control subjects. Therefore, this latter value was used to identify two subgroups inside the overall population of NIDDM patients, i.e. 28 patients (group 1), with whole body glucose utilization rate, above, and 45 patients (group 2), below, the mean value minus 1 SD in the 24 controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Lipoprotein abnormalities in non-insulin-dependent diabetic patients with impaired extrahepatic insulin sensitivity, hypertension, and microalbuminuria.

We investigated whether specific lipoprotein abnormalities are present in non-insulin-dependent diabetes mellitus (NIDDM) patients with hypertension and/or microalbuminuria. Fifteen normotensive normoalbuminuric (H-M-), 32 hypertensive normoalbuminuric (H+M-), and 22 hypertensive microalbuminuric (H+M+) NIDDM patients and 20 sex-, age-, and weight-matched nondiabetic control subjects were studied. Lipoprotein size was measured by nondenaturing polyacrylamide gradient gel electrophoresis; insulin sensitivity was assessed by using a euglycemic hyperinsulinemic clamp and [6,6(2)H]glucose tracer infusion for simultaneous measurement of hepatic glucose output and whole-body glucose utilization. Total plasma and very-low-density lipoprotein cholesterol were higher in H+M+ than in control subjects (5.84 +/- 0.98 versus 4.97 +/- 0.98 and 0.57 +/- 0.54 versus 0.26 +/- 0.21 mmol/L, mean +/- SD, P < .05). Plasma triglycerides were higher in H+M+ than in either control or H-M- subjects (2.17 +/- 1.32 versus 1.18 +/- 0.67 and 1.30 +/- 0.59 mmol/L, respectively; P < .05). The mean low-density lipoprotein diameter was 27.2 +/- 0.8 in control, 26.7 +/- 0.8 in H-M-, 26.5 +/- 0.8 nm in H+M- (P < .05 versus control subjects), and 26.0 +/- 0.8 nm in H+M+ subjects (P < .05 versus control subjects). The mean cholesterol level of the large high-density lipoprotein particles was lower in H+M- and H+M+ (0.37 +/- 0.14 and 0.36 +/- 0.16 mmol/L) than in control and H-M- (0.54 +/- 0.41 and 0.54 +/- 0.27 mmol/L, P < .05) subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Albuminuria↗
PubMed1994

Dyslipoproteinaemia in manifest diabetes.

The prevalence of hypercholesterolaemia is similar in non-insulin-dependent diabetic (NIDDM) patients and in non-diabetic subjects. The prevalence of hypertriglyceridaemia and of low high-density-lipoprotein (HDL) cholesterol is roughly double the norm in NIDDM, but the exact prevalence varies greatly from study to study. Obesity and a familial form of hypertriglyceridaemia (conditions that may alter plasma lipoprotein levels) are frequently observed in NIDDM patients. In carefully controlled NIDDM patients without concomitant primary hyperlipoproteinaemia, body weight may be more important than glycaemic control or the type of treatment plan adopted in determining lipoprotein levels. Hypertriglyceridaemia in NIDDM is a result of both increased very-low-density-lipoprotein (VLDL) synthesis and impaired VLDL catabolism. Whilst low-density-lipoprotein (LDL) levels are normal, the LDL synthesis and removal rates may be increased. Low high-density-lipoprotein (HDL) levels may be due to increased catabolism. In addition to quantitative changes in plasma lipids and lipoproteins. NIDDM patients demonstrate qualitative lipoprotein alterations. The size and density of LDL particles in NIDDM patients are greatly affected by triglyceride levels. Smaller, denser LDL particles have been observed in hypertriglyceridaemic subjects. Glycosylation of apolipoproteins may alter the metabolic properties of lipoproteins. Glycosylated and small, dense LDL have an increased susceptibility to oxidation.

Diabetes Mellitus, Type 2↗
PubMed1993

Levels and physicochemical properties of lipoprotein subclasses in moderate hypertriglyceridemia.

Moderate hypertriglyceridemia is associated with several abnormalities of the plasma lipoprotein particles and it may be a risk factor for atherosclerotic vascular diseases. Plasma lipid, lipoprotein and apolipoprotein levels, as well as lipoprotein composition and physical properties, were examined by ultracentrifugation in a zonal rotor and by gradient gel electrophoresis in 14 patients with moderate hypertriglyceridemia (plasma triglycerides 4.00 +/- 0.32 mmol/l, mean +/- S.D.) and in 14 control subjects. Based on zonal ultracentrifugation hypertriglyceridemic patients have higher levels of cholesterol in all VLDL subclasses (Sf > 200, 100-200, 60-100 and 20-60), in IDL and in small and dense LDL. Both HDL2 and HDL3 cholesterol levels are reduced. The LDL flotation rate is inversely related to plasma triglyceride levels, thus indicating that the higher the plasma triglycerides the smaller and/or denser the LDL are. The triglyceride percent content of LDL2 and HDL3 is increased, while that of esterified cholesterol is reduced in hypertriglyceridemic patients. Gradient gel electrophoresis shows that the LDL peak size is lower (25.2 +/- 0.5 nm, mean +/- S.D.) in hypertriglyceridemic than in control subjects (27.1 +/- 0.4 nm; P < 0.0001). Considering both hypertriglyceridemic and control subjects the LDL peak effluent volume from the zonal rotor (which reflects the LDL flotation rate) is inversely related to the LDL peak size determined by gradient gel electrophoresis (r = -0.71; P = 0.0006) and the plasma triglyceride levels are related to LDL peak effluent volume (r = 0.74; P = 0.0002) and to LDL peak size (r = -0.95; P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoproteins↗
PubMed1993

Lipoprotein compositional abnormalities in type 1 (insulin-dependent) diabetic patients.

Patients with type 1 (insulin-dependent) diabetes mellitus in good metabolic control usually have normal plasma lipid levels yet they have an increased incidence of vascular complications. Abnormalities in the distribution and composition of lipoprotein subfractions might in part be responsible for the macroangiopathy seen in type 1 diabetes mellitus. The plasma lipids, lipoproteins and apolipoproteins were studied in 9 type 1 diabetic patients during conventional insulin therapy and in 14 healthy controls. Plasma lipoproteins were analysed by ultracentrifugation in a zonal rotor to evaluate their concentrations and flotation properties and for compositional analysis. In diabetic patients the mean glycosylated haemoglobin (HbA1c) was 9.44 +/- 1.02% and the plasma lipid concentrations were not significantly different from healthy controls. The very low density lipoprotein (VLDL) subclass cholesterol concentrations were no different in diabetic patients and control subjects, but the VLDL cholesterol/triglyceride ratio was significantly lower in diabetic patients than in control subjects (0.43 +/- 0.05 vs 0.85 +/- 0.14; p < 0.05). The flotation rate LDL2, the major component of low density lipoprotein (LDL) was lower in the diabetic patients compared with the control subjects. The cholesterol concentrations of intermediate density lipoprotein and LDL3, the minor component of LDL, were significantly higher (0.17 +/- 0.03 and 0.83 +/- 0.14 mmol/l respectively) in diabetic patients than in control subjects (0.05 +/- 0.02 and 0.24 +/- 0.08 mmol/l). The flotation properties and cholesterol concentrations of the high density lipoprotein (HDL) subclass, and the protein-lipid composition of LDL2, HDL2 and HDL3, were no different in diabetic patients and control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Lipoprotein abnormalities in hypertriglyceridaemic patients on long-term haemodialysis.

OBJECTIVES: To analyse by ultracentrifugation in a zonal rotor the plasma lipoproteins in hypertriglyceridaemic patients on long-term haemodialysis. DESIGN: Case-control study. SETTING: Tertiary referred care centre. SUBJECTS: Ten consecutive hypertriglyceridaemic patients on haemodialysis and 12 consecutive healthy controls. MAIN OUTCOME MEASURES: Plasma lipid and lipoprotein cholesterol concentrations, lipoprotein physical properties and compositions, apolipoprotein concentrations. RESULTS: Hypertriglyceridaemia in patients undergoing haemodialysis is characterized by an increased amount of small and slow floating very-low density lipoproteins (VLDL), higher concentrations of intermediate density lipoproteins (IDL) and small and dense low-density lipoprotein (LDL) particles; reduced levels of high-density lipoproteins (HDL), in particular of HDL2. The lipoprotein composition of such patients indicates reduced cholesterol ester and increased triglyceride content. Compared to controls, they have lower levels of plasma apolipoprotein A-I and A-II and higher B, C-II, C-III and E values. CONCLUSIONS: The lipoprotein abnormalities observed in hypertriglyceridaemic patients undergoing haemodialysis have recently been associated with an increased incidence of vascular complications and may in part explain the high incidence of vascular disease reported in these subjects.

Aged↗
PubMed1993

Lipoprotein abnormalities in well-treated type II diabetic patients.

OBJECTIVE: To investigate lipoprotein levels and composition in well-treated type II diabetic patients. RESEARCH DESIGN AND METHODS: Cholesterol and triglyceride levels were measured in plasma, VLDL, LDL, and HDL in 120 type II diabetic patients in good to fair metabolic control (HbA1c, 7.2 +/- 1.6%) and in 30 normal control subjects. ApoAI, AII, B, CII, CIII, and E levels in plasma were also determined. RESULTS: The diabetic patients have significantly higher levels of mean plasma cholesterol (5.85 vs. 5.43 mM, P = 0.03), LDL triglycerides (0.41 vs. 0.31 mM, P = 0.003), and HDL triglycerides (0.24 vs. 0.19 mM, P = 0.02), whereas total triglycerides, VLDL cholesterol and triglycerides, LDL cholesterol, and HDL cholesterol are not significantly different from normal control subjects. ApoB (150 vs. 135 mg/dl, P = 0.02) and apoCIII (10.6 vs. 8.4 mg/dl, P = 0.01) are significantly higher in diabetic patients compared with control subjects. No significant differences are observed in all the parameters among diabetic patients treated with diet only, sulphonylurea, sulphonylurea plus biguanides, or insulin. Body weight is significantly related to VLDL lipids. The VLDL triglycerides are inversely related to the HDL cholesterol in both diabetic patients and control subjects. The VLDL triglycerides are directly related to the HDL triglycerides only in diabetic patients. No other lipid or lipoprotein parameters are significantly related to body weight or metabolic control. CONCLUSIONS: Type II diabetic patients in good to fair metabolic control are characterized by minor alterations of the plasma lipids, but LDL and HDL triglycerides, apoB, and apoCIII are increased, thus indicating that the lipoprotein composition is altered, possibly because of an abnormal triglyceride metabolism and/or lipid transfer activity.

Aged↗
PubMed1992

Immunoreactive "calcitonin-like" material in heroin addicts: varying reactivity with different antibodies.

High levels of immunoreactive calcitonin (iCT) in the blood of heroin addicts were previously reported. As it is well known that multiple forms of calcitonin exist in the blood and in tissues, the purpose of the present study was to investigate the immunological nature of the CT-like immunoreactive material found in the blood of these subjects. We investigated 25 addicts, who had been using heroin for more than one year and were hospitalized for a 2 week detoxication program. Blood samples were drawn at the start of the program (when the subjects were still on heroin) and after 5 and 12 days of abstinence from heroin. Twenty-five healthy subjects served as controls. We used 2 commercial RIA kits, calibrated against the same reference material (WHO 70-234), but employing different antisera. One antiserum substantially confirmed the previous findings of increased levels of calcitonin during heroin use, but the other seemed to exclude any change in the hormone concentrations. This suggests that the "calcitonin like" material found in heroin addicts contains some epitopes similar to those found in the calcitonin standard which are detected by the first antiserum. However it lacks other epitopes which are also present in calcitonin standard and which are recognized by the second antiserum. Therefore, this substance seems to be different from the standard human calcitonin 1-32. A possible involvement of a calcitonin analogue (precursor or metabolite) in the biochemical changes occurring during chronic opiate use is suggested.

Adolescent↗
PubMed1992

Lipoprotein sub-fraction levels and composition in obese subjects before and after gastroplasty.

Obesity is frequently associated with several alterations of plasma lipid levels and lipoprotein metabolism. To evaluate the effects of severe obesity and weight loss on plasma lipoprotein sub-class levels and composition 11 grossly obese patients were examined before and six and 12 months after gastroplasty. Plasma lipoproteins were isolated by ultracentrifugation in a zonal rotor under rate flotation conditions. Mean body weight was 121.9 kg before gastroplasty, 97.6 kg after six months, and 90.7 kg after 12 months. Total plasma cholesterol was not affected by the weight reduction. Obese patients were characterized by increased levels of IDL and small dense LDL (LDL3). LDL levels, but not LDL3, were reduced following weight reduction. Plasma apo B levels of obese patients were always higher than in controls and were not affected by the weight reduction. After 12 month's weight loss total HDL cholesterol increased without modification of HDL sub-class cholesterol distribution, which was similar to that of normal controls. Plasma apo AI in obese patients was not affected by changes in body weight, and remained below normal. The percentage protein-lipid composition of LDL2 and HDL3 in obese patients was characterized by a decreased cholesterol ester content before gastroplasty which was normalized 12 months after gastroplasty. The presence of IDL and LDL3 in increased concentrations in severely obese patients may represent a vascular risk factor since similar abnormalities were recently observed in non-obese patients affected with vascular diseases.

Adult↗