Biomedical subjects

L Di Francesco

Publications and source records attributed to L Di Francesco.

At least 37 records · Page 2Linked to original sources

PubMed1996

[Endothelial dysfunction in salt sensitive hypertension].

Plasma endothelin-1 (ET-1) and von Willebrand factor (vWF) levels are elevated in the presence of either macro- or microvascular lesions. Since an increased risk to develop hypertension-related vascular damage has been suggested in human sensitive hypertension, we evaluated both substances in plasma samples from 20 non-diabetic, non obese essential hypertensive men (mean age 49 +/- 4 years). Patients were divided in salt sensitive (n = 9) or salt resistant (n = 11) groups, according to the individual response to both high- and low-sodium diets. Plasma ET-1 levels were also assessed after an oral glucose tolerance test (75 g). Both ET-1 and vWF were higher in salt sensitive than salt resistant patients (ET-1 p < 0.01; vWF p < 0.03). Furthermore, after oral glucose administration, plasma ET-1 concentrations increased very mildly but significantly only in salt sensitive patients (p < 0.05 at 90 min). In conclusion, human salt sensitive hypertension is combined to increased levels of two markers of endothelial damage, and by an augmented ET-1 response to glucose leading, suggesting it is characterized by an increased risk to develop hypertension-related vascular complications.

Adult↗

PubMed1995

Plasma endothelin-1 levels in patients with systemic sclerosis: influence of pulmonary or systemic arterial hypertension.

OBJECTIVES: To investigate the behaviour of circulating endothelin-1 (ET-1) in patients affected by systemic sclerosis and to elucidate the relationship between systemic and pulmonary plasma peptide and arterial pressure levels. METHODS: Plasma ET-1 concentrations were determined in 48 patients affected by systemic sclerosis (41 women, seven men; mean age 47.2 (SD 5.5) years) with or without systemic or pulmonary hypertension (or both). A group of 18 normal volunteers served as controls (15 women, three men; mean age 45.0 (10.1) years). RESULTS: Plasma ET-1 levels were significantly greater in patients affected by systemic sclerosis (1.65 (0.29) pg/ml) than in controls (0.63 (0.19) pg/ml) (p < 0.0001). Pulmonary artery systolic hypertension alone was present in 14 patients with systemic sclerosis (50.5 (8.49) mm Hg, range 37-67 mm Hg), and systemic hypertension alone (160.7 (5.9)/100.6 (3.2) mm Hg) was present in 11 patients. Both conditions were present in 12 patients, while 11 patients had systemic hypertension. There were no significant differences in plasma ET-1 levels between patients with pulmonary hypertension alone (1.62 (0.21) pg/ml) and those with systemic hypertension alone (1.65 (0.43) pg/ml). In particular, patients with normal pulmonary artery and systemic pressures (n = 11) had plasma ET-1 concentrations identical to those found in patients (n = 12) with both pulmonary and systemic hypertension (1.70 (0.15) v 1.64 (0.35) pg/ml, respectively). No correlations were observed between plasma ET-1 and either pulmonary or systemic pressures. CONCLUSION: Systemic sclerosis is characterised by increased plasma ET-1 levels, but neither pulmonary nor systemic hypertension are accompanied by further increase in plasma peptide levels.

Endothelins↗

PubMed1995

Hormonal and renal responses to atrial natriuretic peptide infusion in low-renin hypertension.

Although atrial natriuretic peptide (ANP) levels are often elevated in low-renin hypertensives, the renal and hormonal effects of ANP infusion have never been evaluated in these patients. To address this topic, 27 lean nondiabetic men affected by uncomplicated essential hypertension were studied. Low-renin patients (n = 9, age 42 +/- 3 years) were defined as those individuals in balance on a low NaCl intake (10 mmol NaCl/day for 1 week) who had a plasma renin activity <0.30 ng angiotensin I/l/s, in both the supine and the upright positions. The remaining hypertensives (n = 18, age 41 +/- 4 years) were classified into the normal-renin group. Six age-matched healthy men (age 40 +/- 2 years) served as controls. After plasma renin activity determinations, both patients and controls were replaced on a normal NaCl intake (120 mmol NaCl/day). After 1 week, either ANP (99-126), at a dose (0.7 pmol/kg/min for 3 h) which is known to induce changes in plasma ANP confined to the range of normality, or its vehicle were infused at 1-week intervals, according to a randomized double-blind crossover design. At time 0, low-renin patients had significantly higher (p < 0.05) levels of plasma ANP (12.4 +/- 2.5 fmol/ml) than normal-renin patients (7.2 +/- 2.4 fmol/ ml) and normotensives (7.4 +/- 3.3 fmol/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Plasma endothelin-1 levels in obese hypertensive and normotensive men.

Plasma endothelin-1 (ET-1) levels were studied in 15 obese hypertensive (mean age 48.5 +/- 3.9 years) and 15 obese normotensive men (mean age 49.5 +/- 3.6 years) before and after weight loss due to an 800 kcal/day diet lasting 12 weeks. Circulating peptide concentrations were also assessed in nonobese hypertensive (n = 11) and normotensive men (n = 12). Baseline plasma ET-1 levels were similar in obese hypertensive (0.87 +/- 0.22 pg/ml) and obese normotensive men (0.91 +/- 0.30 pg/ml). In seven obese hypertensive men, caloric restriction normalized blood pressure levels (systolic: from 166.6 +/- 8.1 to 145.0 +/- 6.3 mmHg, P < 0.0001; diastolic: from 106.6 +/- 5.1 to 89.1 +/- 2.0 mmHg, P < 0.0001) and decreased body mass index (BMI) (from 33.4 +/- 1.6 to 29.6 +/- 2.1 kg/m2, P < 0.002) and plasma ET-1 levels (from 0.93 +/- 0.21 to 0.64 +/- 0.26 pg/ml, P < 0.05). In the remaining obese hypertensive men (n = 8), blood pressure levels were not normalized by caloric restriction despite a significant decrease of BMI and plasma ET-1 levels (from 0.83 +/- 0.23 to 0.60 +/- 0.16 pg/ml, P < 0.04). Weight loss also significantly decreased BMI and ET-1 (from 0.91 +/- 0.30 to 0.65 +/- 0.19 pg/ml, P < 0.01) in obese normotensive men. Baseline ET-1 and fasting insulin levels were significantly correlated in obese hypertensive (r = 0.518, P < 0.05) and obese normotensive men (r = 0.535, P < 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Demonstration of Rickettsia Conorii-induced coagulative and platelet activation in vivo in patients with Mediterranean spotted fever.

Endothelial injury in vivo induced by Rickettsia Conorii, the etiologic agent of Mediterranean Spotted Fever (MSF) has been recently demonstrated. We sought to determine whether platelet and/or coagulative activation in vivo can be demonstrated in the acute phase of MSF, through measurements of a major metabolite of thromboxane (TX) in the urine (11-dehydro-TXB2) and of plasma prothrombin fragment 1 + 2, whose levels reflect activation of prothrombin to thrombin. Moreover, we measured plasma endothelin-1 as marker of endothelial dysfunction. Our results provide biochemical evidence for the occurrence of TXA2-dependent platelet activation and thrombin generation in vivo, together with endothelial dysfunction. These phenomena could account for clinical manifestations of MSF, such as vasculitis and focal microthrombus formation. These results could also provide a rationale for testing the efficacy of aspirin or heparin in reducing the prothrombotic status of Rickettsiae diseases.

Acute Disease↗

PubMed1994

Cytosolic sialidase from pig brain: a 'protein complex' containing catalytic and protective units.

Pig brain cytosolic sialidase purified to homogeneity, showed a single protein band on SDS-PAGE under non-reducing conditions, and three bands using reducing conditions, suggesting a complex of different units. The sialidase complex (molecular mass, M(r), 180 kDa) was resolved into a catalytic unit (M(r) 30 kDa), active but very liable upon storage at 4 degrees C and freezing and thawing, and two protective units (66 kDa and 42 kDa), inactive, but capable to stabilize the catalytic unit. Recombination of the catalytic and protective units (optimal ratio, 1:1, by weight) gave rise to a stable active complex. Using GD1a as substrate, the catalytic unit showed a Michaelis-Menten kinetics, and the complex a sigmoid-shaped kinetics, whereas a Michaelis-Menten kinetics was exhibited with MU-NeuAc in both cases. The apparent Vmax and Km values of the catalytic unit for MU-NeuAc and GD1a were 105.1 and 110.0 mU/mg protein, and 4.2 x 10(-5) and 1.6 x 10(-5) M, respectively. The model we propose for cytosolic sialidase complex is one of each protective units and 2-3 catalytic units. The sialidase complex and protective units did not display any beta-D-galactosidase, beta-D-N- acetylglucosaminidase, alpha-L-fucosidase, alpha-D-glucosidase and carboxypeptidase activities.

Animals↗

PubMed1994

Salt-sensitivity is associated with a hyperinsulinaemic and hyperglycaemic response to atrial natriuretic peptide infusion in human essential hypertension.

To evaluate the influence of salt-sensitivity on the plasma insulin and glucose response to infusion of ANP, we studied 22 men with essential hypertension, who were between 40 and 60 years old. After 1 month under normal Na+ intake (120 mmol Na+ per day), patients were randomly assigned to receive either ANP (0.04 micrograms.kg-1.min-1) (n = 15) or vehicle (50 ml saline) (n = 7) over a 60-min period, while in the supine position. Plasma insulin and glucose were measured at time -60, 0, 20, 40, 60, 120, 180, 240 min. Ten days after ANP infusion, blood pressure sensitivity to changes in dietary salt intake was assessed according to a randomized double-blind crossover protocol. Patients were classified into two groups either salt-sensitive (n = 8) or salt-resistant (n = 7). Our results showed that plasma insulin and glucose did not change during ANP infusion in both groups. However, both plasma insulin (from 75.6 +/- 45.1 pmol/l at 60 min to 121.2 +2- 48.6 pmol/l at 240 min, p < 0.05 vs time 0) and glucose levels (from 4.86 +/- 0.73 mmol/l at 60 min to 6.56 +/- 1.03 mmol/l at 240 min, p < 0.01 vs time 0) rose after discontinuation of ANP in salt-sensitive patients, but did not change at all in salt-resistant patients. In conclusion, this randomized vehicle-controlled study demonstrates that plasma insulin and glucose levels increase in salt-sensitive hypertensive patients after the infusion of ANP. The increase of plasma insulin levels observed after ANP discontinuation, if occurring under physiologic conditions, could influence the blood pressure sensitivity to dietary Na+ intake.

Adult↗

PubMed1994

Levels of circulating intercellular adhesion molecule 1 and E-selectin in serum and synovial fluid of juvenile chronic arthritis patients.

OBJECTIVE: To measure the levels of two adhesion molecules (AM), soluble intercellular adhesion molecule 1 (sICAM-1) and soluble E-selectin (sE-selectin), in serum and synovial fluid (SF) of patients with juvenile chronic arthritis (JCA). METHODS: Both soluble AM levels were tested, in serum and synovial fluid (SF) samples, with an enzyme-linked immunosorbent assay (ELISA) method. RESULTS: Serum levels of sICAM-1 and sE-selectin in JCA patients were not significantly different from those of a control group. Synovial fluid levels of sICAM-1, but not of sE-selectin, assayed significantly higher (p < 0.05) in JCA patients than in controls. Moreover SF levels of both molecules correlated negatively with disease duration, being higher in the earliest phases. No significant correlations were found between JCA sICAM-1 and sE-selectin levels and leukocyte count or ESR. CONCLUSIONS: These observations may signify a more important role of ICAM-1 than E-selectin in the migration of inflammatory cells into JCA SF. The negative correlation of both AMSF levels in JCA patients with disease duration could reflect a higher expression of ICAM-1 and E-selectin during the earliest phases of the disease.

Adolescent↗

PubMed1993

Human erythrocyte sialidase is linked to the plasma membrane by a glycosylphosphatidylinositol anchor and partly located on the outer surface.

Treatment of human erythrocyte ghosts with phosphatidylinositol-phospholipase C (PIPLC) from Bacillus cereus liberated the ghost-linked sialidase. Maximal release of sialidase (about 70% of total) was achieved by incubating ghosts at 37 degrees C for 60 min, at pH 6.0, with PIPLC (PIPLC total units/ghost protein ratio, 4.5 each time) added at the beginning of incubation and every 15 min (four subsequent additions). Liberated sialidase was fully resistant to at least four cycles of rapid freezing and thawing and to storage at 4 degrees C for at least 48 h. The liberated enzyme had an optimal activity at pH 4.2, degraded ganglioside GD1a better than methylumbelliferyl N-acetylneuraminic acid (about fourfold), and gave a Km value of 2.56 x 10(-4) M and an apparent Vmax of 2.22 mU per mg protein on GD1a. Treatment of intact erythrocytes with PIPLC (PIPLC total units/erythrocyte protein ratio, 8), under conditions where haemolysis was practically negligible, caused liberation of 10-12% of membrane linked sialidase, indicating that the enzyme is, at least in part, located on the outer surface of the erythrocyte membrane. It is concluded that the erythrocyte membrane sialidase is anchored by a glycosylphosphatidylinositol structure sensitive to PIPLC action, and is partly located on the outer surface.

Erythrocyte Membrane↗

PubMed1993

The influence of salt sensitivity on the blood pressure response to exogenous kallikrein in essential hypertensive patients.

In order to verify the influence of salt sensitivity on the blood pressure response to orally administered kallikrein, we evaluated the efficacy of glandular kallikrein (derived from porcine pancreas) in 28 essential hypertensives (21 males and 9 females) aged between 40 and 62 years. After a placebo run-in period, the patients were assigned to receive oral kallikrein therapy (150 IU 3 times a day; n = 18 patients) or placebo (n = 10 patients) over a period of 8 days in a random double-blind fashion. In the salt-resistant patients (n = 8), kallikrein administration did not modify blood pressure levels. In the same group, natriuresis increased significantly after the treatment [from 94.51 +/- 10.76 to 111.65 +/- 23.19 mEq/24 h (mmol/24 h), p < 0.039]. In the salt-sensitive patients (n = 10), blood pressure decreased with the kallikrein therapy (systolic: from 158.50 +/- 9.20 to 144.50 +/- 10.12 mm Hg, p < 0.005; diastolic: from 99.50 +/- 2.16 to 90.0 +/- 3.67 mm Hg, p < 0.024). In the same patients, urinary Na+ excretion increased considerably after the kallikrein treatment (from 101.07 +/- 18.36 to 134.34 +/- 18.27 mEq/24 h, p < 0.0001). Therefore, our data indicate that the oral kallikrein administration reduces blood pressure levels only in the salt-sensitive hypertensives. In both the salt-sensitive and the salt-resistant groups a marked increase in the 24-hour urinary excretion of sodium was observed after the kallikrein treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Occurrence of sialidase activity in two distinct and highly homogeneous populations of lysosomes prepared from the brain of developing mouse.

Light and heavy lysosomes of mouse forebrain were separated from each other by centrifugation on a Percoll gradient. Light lysosomes were then freed from mitochondria and membranes by sucrose density gradient centrifugation and further purified by floatation-centrifugation on a sucrose gradient. The final preparations of light and heavy lysosomes, fairly homogenous, carried sialidase activity, assayed on MU-NeuAc. The optimal pH was 4.0 and 4.2, the apparent Km value 2.8 x 10(-5) M and 4.2 x 10(-5) M and the apparent Vmax value 0.11 and 0.47 mU.mg-1 protein, for the light and heavy lysosome sialidase, respectively. From 4 days to adulthood the specific activity of the light and heavy lysosome sialidase increased 3-fold and 1.7-fold, respectively.

Age Factors↗

PubMed1981