Dynamics of water-containing sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reverse micelles: A high-frequency dielectric study.
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Biomedical subjects
Publications and source records attributed to A Santucci.
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Active and inactive urinary kallikrein excretion rates were evaluated in 43 essential hypertensive men (45.4 +/- 5.6 yr) after normal-(120 mmol/day), low-(20 mmol/day), and high-(240 mmol/day) NaCl diets were given for 2 wk each. Patients were classified as salt-sensitive, salt-resistant, or counterregulating, on the basis of their blood pressure responses to the different NaCl intakes. Resulting data show that active and inactive kallikrein excretion rates were lower (P < 0.001) in salt-sensitive (active, 0.59 +/- 0.27 U/24 h; inactive, 3.45 +/- 1.31 U/24 h) than in salt-resistant (active, 1.41 +/- 0.35 U/24 h; inactive, 6.93 +/- 2.68 U/24 h) and in counterregulating hypertensive patients (active, 1.37 +/- 0.39 U/24 h; inactive, 6.32 +/- 2.58 U/24 h) after the normal NaCl diet. Salt-sensitive hypertensive patients showed also higher plasma digoxin-like substance (P < 0.001), atrial natriuretic peptide (P < 0.001), and fasting insulin (P < 0.005) levels than the other subgroups. Active kallikrein decreased after high and increased after low-NaCl intake in all groups. Inactive kallikrein varied similarly to active one in salt-resistant patients and counterregulating patients, whereas it increased during salt-loading in salt-sensitive patients. Consequently, the active/total kallikrein ratio decreased in salt-sensitive patients (from 20.2 +/- 3.5 to 5.82 +/- 1.02%, P < 0.05) when they switched from low- to high-NaCl intake, and the ratio was lower in these patients than in the other subgroups (P < 0.0001) after the high-NaCl diet. In conclusion, active and inactive kallikrein excretions after normal-NaCl intake are reduced in salt-sensitive hypertensive patients. The divergent active and inactive kallikrein responses to dietary NaCl changes in salt-sensitive patients could indicate an impairment of inactive to active kallikrein conversion during NaCl loading as a new mechanism in human salt-sensitive hypertension.
To evaluate the behavior of active kallikrein excretion in salt-sensitive and salt-resistant hypertensive patients during changes in sodium-chloride (NaCl) intake, 61 male, nonobese, nondiabetic outpatients affected by uncomplicated essential hypertension were given a diet that contained 140 mmol NaCl per day for 2 wk. Patients then received either a low- (20 mmol NaCl/day) or a high- (320 mmol NaCl/day) sodium diet for 2 wk, according to a randomized, double-blind, cross-over protocol. Hypertensive patients were classified as salt sensitive when their diastolic blood pressure rose by at least 10 mm Hg after the high-sodium diet, and decreased by at least 10 mm Hg after the low-sodium diet, considering as baseline blood pressure values those that were taken at the end of the 140 mmol NaCl/day intake period. The remaining patients were classified as salt resistant or, when diastolic blood pressure increased by 10 mm Hg or more after low-sodium intake, as counter-regulating. Twenty-three patients were therefore classified as salt sensitive, 28 as salt resistant, and 10 as counter-regulating. The baseline active kallikrein excretion was significantly lower (P < 0.0001) in salt-sensitive (0.62 +/- 0.31 U/24 h) patients than in salt-resistant (1.39 +/- 0.44 U/24 h) and counter-regulating patients (1.27 +/- 0.38 U/24 h). Surprisingly, the kallikrein response to changes in sodium intake was similar in all subgroups, although enzyme excretion was always at the lowest level in salt-sensitive hypertensive patients. This latter group also showed the highest plasma atrial natriuretic peptide levels (28.2 +/- 8.5 fmol/mL, P < 0.0001 versus salt-resistant and counter-regulating patients), and the greatest peptide increment with sodium load (P < 0.0001 versus salt-resistant and counter-regulating patients). Counter-regulating patients showed the steepest increase in plasma renin activity (from 0.24 +/- 0.18 to 0.83 +/- 0.21 ng/L per s, P < 0.001) and decrease of plasma atrial natriuretic peptide (from 26.1 +/- 6.3 to 6.8 +/- 3.1 fmol/mL, P < 0.001) when switched from a high to a low-sodium intake. In conclusion, salt-sensitive hypertensive patients excrete less active kallikrein than do salt-resistant and counter-regulating patients, but maintain a normal enzyme response to changes in dietary sodium intake. The exaggerated response of atrial natriuretic peptide to high-sodium intake that was observed in the same patients could be compensating for an impaired renal capability to excrete a sodium load.
OBJECTIVE: To evaluate the effects of captopril on circulating catecholamine levels in NIDDM patients and the possible relationship between captopril-related changes in circulating catecholamine levels and insulin sensitivity. RESEARCH DESIGN AND METHODS: Fourteen nonobese normotensive NIDDM men (aged 44.5 +/- 5.1 years) underwent a 2-h euglycemic-hyperinsulinemic clamp (40 mU.m-2.min-1). Baseline evaluation of insulin sensitivity was followed by the random assignment of each patient to either captopril or placebo treatment, according to a crossover double-blind design. Euglycemic-hyperinsulinemic clamp studies were then repeated for all patients after both placebo and captopril treatments. Plasma norepinephrine (NE) and epinephrine (E) levels were assessed before, during, and after each clamp. RESULTS: Resulting data showed that plasma catecholamine levels increased during baseline euglycemic-hyperinsulinemic clamp (NE: +23.6% time 0 vs. time 120 min, P < 0.05; E: +24.8% time 0 vs. time 120 min, P < 0.05). Captopril treatment significantly increased total glucose uptake (from 19.0 +/- 9.0 to 26.8 +/- 10.1 mmol.kg-1.min-1, P < 0.05) and reduced baseline plasma NE (P < 0.001) and E (P < 0.05) levels. However, the magnitude of the NE (+25.7% time 0 vs. time 120 min, P < 0.001) and E (+27.2% time 0 vs. time 120 min, P < 0.05) increments during euglycemic hyperinsulinemia were not affected by the drug. Percentage changes in the ratio of total body glucose uptake to circulating insulin levels and corresponding decrements of baseline plasma E levels after captopril therapy were negatively correlated (r = -0.57, P < 0.05). CONCLUSIONS: The reduction of circulating catecholamines could contribute, at least in part, to the captopril-related amelioration of insulin sensitivity.
OBJECTIVE: To assess the effect of oral glucose loading on plasma endothelin-1 (ET-1) levels in humans. RESEARCH DESIGN AND METHODS: A total of 75 g D-glucose was given orally to 14 nonobese nondiabetic essential hypertensive subjects (eight men and six women, mean age 43.1 +/- 3.0 years) and eight normotensive subjects (four men and four women, mean age 45.2 +/- 4.1 years). Blood samples for plasma ET-1 measurement were drawn every 30 min for 2 h and then at 180 and 240 min. RESULTS: After glucose load, insulin increased more significantly in hypertensive subjects than in normotensive subjects at times 60 (P = 0.004) and 90 (P = 0.001) min. Glucose loading was followed by a mild but significant increase in circulating ET-1 levels in both groups (hypertensive subjects, from 0.87 +/- 0.25 pg/ml at time 0 to 1.64 +/- 0.33 pg/ml at 120 min and 1.74 +/- 0.38 pg/ml at 180 min, P < 0.05; normotensive subjects, from 0.82 +/- 0.38 pg/ml at time 0 to 1.42 +/- 0.18 pg/ml at 180 min, P < 0.05). Whereas baseline ET-1 levels were similar between the two groups, postload ET-1 levels were higher in hypertensive subjects than in normotensive subjects (P = 0.003 at 120 min; P = 0.04 at 180 min). CONCLUSIONS: This study indicates that significant changes in circulating ET-1 levels occur after oral glucose loading, probably due to a glucose-induced increment in endogenous insulin concentration.
BACKGROUND: Blood pressure variability is a determinant of target organ damage in essential hypertension, but its independent prognostic significance has not yet been assessed in prospective studies of cardiovascular morbidity and mortality. OBJECTIVE: To assess the relationship between blood pressure variability, assessed non-invasively using 24 h ambulatory blood pressure monitoring and subsequent incidence of cardiovascular morbid events in persons with essential hypertension. DESIGN: Prospective observational study. PATIENTS AND METHODS: We followed for up to 8.6 years (mean 2.92) 1372 individuals with essential hypertension whose initial off-therapy diagnostic work-up included 24 h non-invasive ambulatory blood pressure monitoring. Those with a standard deviation of daytime or night-time blood pressure below or above the group mean were classified as having low or high blood pressure variability, respectively. One hundred and eighty-two participants underwent repeated ambulatory blood pressure monitoring and echocardiography during follow-up, 2.7 years later. RESULTS: Target organ damage score was greater in the participants with high variability of daytime (P = 0.004) and night-time (P = 0.011) systolic blood pressure than in those with low blood pressure variability. In those who underwent repeated echocardiography, for every quartile of baseline ambulatory blood pressure, left ventricular mass at follow-up was greater (all P < 0.05) in those with high baseline blood pressure variability than in those with low baseline variability. During follow-up there were 106 major cardiovascular morbid events. Event rate was 1.99 and 3.26 events per 100 patient-years, respectively, in participants with low and high variability of daytime systolic pressure and 1.98 and 3.38 events per 100 patient-years, respectively, in those with low and high variability of night-time systolic pressure (log-rank test: both P < 0.05). However, in a Cox multivariate analysis, the variability score for daytime and night-time systolic pressure failed to enter the model (age, diabetes mellitus, previous cardiovascular events and average night-time systolic pressure were independently associated with cardiovascular events). CONCLUSION: Increased blood pressure variability, assessed with non-invasive monitoring, is associated with a higher incidence of cardiovascular morbid complications of hypertension, but also with a higher blood pressure, older age and a higher prevalence of diabetes mellitus. Because of the relevant predictive effect of these associated factors, the adverse prognostic significance of increased blood pressure variability is no longer detectable in multivariate analysis.
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In order to evaluate the effect of atrial natriuretic peptide (ANP) infusion on plasma and urinary digitalis-like substance (DLS) levels, 18 essential hypertensive males (mean age 45.6 +/- 3.8 y) were studied. After 1 week on a normal NaCl intake (120 mmol/24h), patients were randomly double-blindly assigned to receive either ANP (99-126) (0.3 microgram/kg/min) (number of patients = 10) or its vehicle (50 ml isotonic saline) (8 patients) over a period of 60 min, in supine position. Plasma and urinary DLS levels were measured at time -60, 0, 30, 60, 120, 180, and 240 min (infusion time from 0-60 min). During ANP infusion, plasma DLS levels decreased significantly (from 25.2 +/- 6.8 pg/ml at time 0 to 12.5 +/- 5.6 pg/ml at 60 min, p < 0.01), while urinary DLS excretion increased (from 60.5 +/- 26.1 pg/ml at time 0 to 246.3 +/- 34.2 pg/ml at 30 min, p < 0.0001). and 402.3 +/- 44.1 pg/ml at 60 min, p < 0.0001). After 3 h from the end of ANP infusion, both plasma and urinary DLS returned to baseline levels (20.5 +/- 14.4 pg/ml and 84.5 +/- 34.2 pg/ml, respectively). Taken together, our data show that ANP infusion significantly increases urinary DLS excretion, while decreasing its circulating levels. This phenomenon could explain the different response of ANP and DLS to some stimuli, such as acute volume expansion. In fact, the rapid increment of plasma ANP due to an acute increase of extracellular fluid volume might simultaneously inhibit the increase in circulating DLS levels by promoting the urinary excretion of this substance.
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.
OBJECTIVES: We examined the prognostic significance of concentric remodeling of the left ventricle in patients with essential hypertension and normal left ventricular mass on echocardiography. BACKGROUND: An echocardiographic pattern of concentric remodeling of the left ventricle has been associated with clinical features of increased cardiovascular risk, but the independent prognostic value of this finding in hypertensive patients with normal left ventricular mass has not been established. METHODS: Six hundred ninety-four patients with essential hypertension and normal left ventricular mass (< 125 g/m2) on echocardiography were prospectively followed up for < or = 7.7 years (mean 2.71). Baseline echocardiography and 24-h noninvasive ambulatory blood pressure monitoring were performed in all patients at the time of initial diagnostic evaluation. Concentric remodeling was defined by the thickness of the septum or posterior wall divided by the left ventricular radius at end-diastole > or = 0.45. RESULTS: Prevalence of concentric remodeling was 39.2%. During follow-up there were 29 cardiovascular morbid events. Cardiovascular morbidity, expressed as the combined number of fatal and nonfatal events per 100 patient-years, was 1.53 in the overall study group, 1.12 in the subgroup with normal left ventricular geometry and 2.39 in that with concentric remodeling. After assessment of the independent association with several covariates (age, gender, diabetes, left ventricular mass index, mean clinic blood pressure and mean 24-h ambulatory blood pressure) in Cox proportional hazard models, the risk of cardiovascular morbid events was higher in the group with concentric remodeling than in that with normal geometry (relative risk 2.56, 95% confidence interval 1.20 to 5.45, p < 0.01). CONCLUSIONS: Concentric remodeling of the left ventricle, defined by the thickness of the septum or posterior wall divided by the left ventricular radius at end-diastole > or = 0.45, is an important and independent predictor of increased cardiovascular risk in hypertensive patients with normal left ventricular mass on echocardiography.
In a previous study we found that two glycoproteins with apparent molecular weights of 220 kD and 180 kD account for 80-90% of the material dissolved from the vitelline coat of the egg of the bivalve mollusk, Unio elongatulus (Focarelli and Rosati, 1993: Mol Reprod Dev 35:44-51). In this study we isolated and purified these glycoproteins by electroelution. The two proteins differ in many respects: the 180-kD molecule is acidic in nature and highly heterogeneous, whereas the 220-kD protein is neutral and less heterogeneous. Both seem to have O- and N-linked oligosaccharide chains. The 180-kD protein contains 13-16% carbohydrate, whereas the 220-kD molecular contains only 7-8%. Amino acid analysis and peptide mapping also show that each protein represents a unique polypeptide chain.
To evaluate the effect of captopril on plasma endothelin-1 (ET-1) levels and insulin sensitivity, 15 lean normotensive men (51.6 +/- 3.8 years) affected by non-insulin-dependent diabetes mellitus (NIDDM) underwent 2-h euglycemic hyperinsulinemic clamp. Each patient was then assigned to receive either captopril (25 mg twice daily for 1 week) or placebo, in a double-blind randomized fashion, before repeating clamp. At baseline, plasma ET-1 levels were 0.77 +/- 0.25 pg/mL in captopril (n = 10) and 0.83 +/- 0.3 pg/mL in placebo patients (n = 5). A twofold increase in plasma ET-1 levels occurred during the 2-h insulin infusion in both groups (P < .05 after 60 and 120 min), with a rapid return to baseline after 30 min from insulin withdrawal. After 1 week of therapy, total glucose uptake significantly increased in captopril (from 3.71 +/- 1.70 mg/kg/min to 4.24 +/- 1.72 mg/kg/min, P < .03) but not in placebo patients. Plasma ET-1 levels significantly decreased after captopril therapy (0.48 +/- 0.25 pg/mL at time 0, P < .03 v pretreatment levels), but were unaffected by placebo. Moreover, captopril slightly reduced the magnitude of ET-1 increment during insulin infusion (0.65 +/- 0.28 pg/mL and 0.88 +/- 0.48 pg/mL at 60 and 120 min, respectively, P < .05 v time 0). As a consequence, during the second insulin infusion circulating ET-1 levels were significantly lower in captopril- than in placebo-treated patients at time 0 (P < .02), 60 (P < .002), 120 (P < .004), and 150 min (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)
PURPOSE: To investigate the behavior of circulating endothelin (ET)-1 concentrations in patients affected by systemic sclerosis, and to elucidate the possible relationships existing in this disease among plasma peptide levels, pulmonary hypertension, and lung fibrosis. PATIENTS AND METHODS: Circulating ET-1 levels were determined by reverse-phase, high-pressure liquid chromatography followed by sensitive radioimmunoassay in 20 patients affected by systemic sclerosis (18 women and 2 men, mean age 48.1 +/- 13.7 years) with or without pulmonary hypertension as evaluated by Doppler echocardiography, or lung fibrosis as measured by a score method based on lung examination by high-resolution computed tomography (HRCT). A group of 18 normal volunteers served as controls (15 women and 3 men, mean age 45.0 +/- 10.1 years). RESULTS: Plasma ET-1 levels were significantly higher (P < 0.001) in patients with systemic sclerosis (1.72 +/- 0.28 pg/mL) than in control subjects (0.63 +/- 0.06 pg/mL). Pulmonary artery systolic hypertension was detected in 10 patients (50%) with systemic sclerosis (56.2 +/- 18.0 mm Hg, range 37 to 97) versus none of the control subjects (30.2 +/- 2.2 mm Hg, P < 0.0001). Lung fibrosis was present in 12 patients (60%), with an HRCT overall score of 9.0 +/- 4.6. There were no significant differences in plasma ET-1 levels between patients with pulmonary hypertension (1.58 +/- 0.20 pg/mL) or without it (1.76 +/- 0.39 pg/mL, P = 0.188, not significant [NS]); or between patients with lung fibrosis (1.65 +/- 0.14 pg/mL) or without fibrosis (1.78 +/- 0.37 pg/mL, P = 0.290, NS). In particular, 6 patients had neither pulmonary hypertension nor lung fibrosis. In these patients, plasma ET-1 levels were similar compared with the others (1.85 +/- 0.49 versus 1.66 +/- 0.13, respectively; P = 0.180, NS). No correlations were observed between ET-1 levels and either pulmonary pressure levels or HRCT overall scores. CONCLUSIONS: The use of a sensitive assay, highly selective for ET-1, showed higher levels of circulating peptide in patients affected by systemic sclerosis than in control subjects. Neither pulmonary hypertension nor lung fibrosis was accompanied by a further rise in plasma ET-1 concentrations.
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We report on the immunophenotype, clinical findings and response to aggressive chemotherapy of 18 patients with mediastinal large B-cell lymphoma (MLCL). Cases were collected from a series of 286 high-grade non-Hodgkin's lymphomas (HG-NHL) which, in the period September 1988 to August 1991, were enrolled in a prospective multicentre trial designed to compare the MACOP-B and F-MACHOP regimens. Immunostaining on frozen sections revealed a previously unrecognized phenotype, i.e. co-expression of B-cell (CD19, CD20, CD22, Ig-associated dimer) and activation-associated antigens (CD30 and CDw70) in about 60% of MLCL cases; in contrast, the activation-associated antigens CD25 and Ki-27 (unclustered) were consistently negative. This peculiar phenotype may reflect a derivation of the tumour from a subset of thymic activated B cells. Clinically, the patients (median age 31 years; F/M ratio 2.6) presented with bulky mediastinal mass (72%) associated with mediastinal syndrome in > 50% cases; disease was stage IIA in most cases. All 18 patients received aggressive chemotherapy (F-MACHOP 11; MACOP-B 7). Complete response (CR) was achieved in 57.1% of cases treated with MACOP-B. In contrast, the response of the 11 MLCL treated with F-MACHOP was poor (CR 18.2%) as compared to that of the 135 HG-NHL treated with the same regimen during the trial (CR 69.6%). This difference was still statistically significant after adjusting for negative prognostic factors (mediastinal mass > 10 cm plus increased LDH) and suggests that F-MACHOP might not be the most appropriate regimen for this kind of lymphoma.
The event-related potential P300 has been studied in 15 migraine without aura sufferers, and in 15 episodic tension-type headache sufferers, during pain-free periods and during spontaneous headache attacks. There were no variations of potential, either of P3 latency or N2-P3 amplitude, in either group during the interictal period. Similarly, there were no variations of the P300 parameters in the group of tension-type headache subjects during headache attacks; by contrast, a significant elongation of latency (P < 0.01) and an increment of N2-P3 wave amplitude (P < 0.002) was observed in the group of migraineurs. The authors discuss the data in accordance with the etiopathogenic theories of migraine and the hypothesis that acetylcholine and norepinephrine are the neurotransmitter able to affect the event-related potential P300, which reflects cerebral activity during sensory information processing and analysis.
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.