Search PubMed⌕ Search

Biomedical subjects

C Vergassola

Publications and source records attributed to C Vergassola.

14 recordsLinked to original sources
PubMed1997

Ambulatory blood pressure monitoring: how reproducible is it?

We tested the reproducibility of ambulatory blood pressure monitoring (ABPM) by the use of agreement plots. Thirty-two normotensive volunteers underwent ABPM on four separate days (interval 28 days), on the same typical weekday. Sleeping time was restricted to the ABPM nighttime subperiod from 11:00 PM to 7:00 AM. Twenty-four-hour average values-both systolic and diastolic-daytime average values, and nighttime average values, as well as standard deviation (SD) values, were analyzed for differences (analysis of variance). Adaptation occurred from the first to the fourth ABPM, ie, average 24 h, daytime, and nighttime values were lower (-1 to -3 mm Hg) during the fourth recording than the first (P < .05 to P < .01). The agreement analysis showed a surprisingly high agreement among the four data sets (ie, differences from +/-2.54 to +/-5.92 mm Hg; +/-2 SD of the distribution). We concluded that reproducibility of ABPM seems excellent, but adaptation may occur, even in normotensive volunteers under research conditions. Caution must be paid before labeling a patient as hypertensive, because initial ABPM may yield higher values than later monitorings.

Adult↗
PubMed1996

Blood pressure evaluation by noninvasive and traditional methods. Consistencies and discrepancies among photoplethysmomanometry, office sphygmomanometry, and ambulatory monitoring. Effects of blood pressure measurement.

Three hundred eight outpatients referred for hypertension were studied. A continuous beat-to-beat noninvasive recording (Finapres) of blood pressure evaluated the blood pressure increase (9 mm Hg systolic and 4 mm Hg diastolic) induced by office sphygmomanometry. Thereafter, patients underwent a 24-h ambulatory blood pressure monitoring. The evaluation against Finapres showed that office sphygmomanometry overestimates the systolic blood pressure by 3 +/- 36 mm Hg (mean +/- 2 SD) and the diastolic blood pressure by 15 +/- 25 mm Hg (mean +/- 2 SD). Blood pressure monitoring showed similar discrepancies. On the basis of both monitoring (normalcy defined from a population of 550 normotensive subjects) and office sphygmomanometry, patients were considered normotensive, hypertensive (either untreated or under active drug treatment), white coat hypertensive (monitoring below the 95th percentile and sphygmomanometry more than 140/90 mm Hg, either untreated or under active drug treatment), and reverse white coat patients (monitoring over the 95th percentile and sphygmomanometry less than 140/90 mm Hg). Patients showed different levels of alert reaction (the highest in white coat hypertensive and the lowest in reverse white coat hypertensive patients), and a similar increase in blood pressure induced by conventional sphygmomanometry. During initial readings of ambulatory monitoring, blood pressure decreased from the first reading to the third reading. This decrease is related to the increase of blood pressure under sphygmomanometry. Caution should be paid in interpreting results of sphygmomanometry (error level in the single patient as high as +/- 40 mm Hg), and interpreting and averaging results of the first hour of blood pressure monitoring (variably affected by the alert reaction to the clinical environment).

Adolescent↗
PubMed1995

Effects of opioid substances on cAMP response to the beta-adrenergic agonist isoproterenol in human mononuclear leukocytes.

The effects of different opioid substances on isoproterenol and forskolin-stimulated cyclic AMP (cAMP) intracellular accumulation, and on the binding of 125I-pindodol (IPIN) to beta 2-adrenoceptors were studied in human mononuclear leukocytes (MNL). The opioids used were alpha-endorphin, beta-endorphin, tau-endorphin, DAGO (a mu receptor agonist), dermenkephalin (a delta receptor agonist and morphine. Only morphine was able to increase the cAMP response to isoproterenol. The EC50 of isoproterenol for cAMP accumulation was shifted leftward by morphine; this effect was blocked by naloxone. On the contrary, the cAMP response to forskolin, direct activator of adenylate cyclase, was similar in the control test with respect to the experiments with morphine. The five opioid peptides induced no changes in the dose-response curves with isoproterenol and forskolin. Furthermore, none of the opioids induced changes in the IPIN binding. Our data show that morphine is able to exert a significant enhancement of the response of beta 2-adrenergic receptors to isoproterenol in human mononuclear leukocytes. This effect seems to be mediated by mu opioid receptors and seems to involve G protein.

Adult↗
PubMed1995

Yohimbine effects on blood pressure and plasma catecholamines in human hypertension.

The purpose of this study has been to test the hypothesis of an alpha 2-adrenoreceptor alteration in human essential hypertension. The design of the study involved the oral administration of 10 mg yohimbine, an alpha 2-adrenergic antagonist, to 25 healthy volunteers and 29 sex- and age-matched untreated hypertensive patients. Volunteers and patients were studied twice in random order, after placebo or yohimbine treatment, in supine and upright positions. Arterial pressure and heart rate were monitored by servoplethysmomanometry, and venous plasma catecholamines were determined by HPLC with electrochemical detection. Yohimbine induced a significant increase in diastolic pressure only in the hypertensive patients. Plasma norepinephrine was increased significantly in both yohimbine-treated groups, but the percent increase of plasma norepinephrine after the standing test was decreased significantly only in the healthy yohimbine-treated subjects. Plasma dopamine was increased significantly only in the healthy yohimbine-treated subjects. The response of plasma dopamine to the upright position was modified only in the healthy yohimbine-treated subjects. The decrease observed after 2 min of standing was abolished, showing the involvement of alpha 2-adrenoreceptors in the physiologic response of plasma catecholamines in healthy volunteers. Our data may be consistent with some in vivo evidence of an alpha 2-adrenoreceptor desensitization or an alteration in the balance of alpha-adrenoreceptors in human hypertension.

Adult↗
PubMed1993

Evidence for interactions between HLA system class I and beta-adrenergic receptors in human mononuclear leukocytes.

In order to determine the possible interactions between histocompatibility leukocyte antigen (HLA) -class I antigens and beta-adrenergic receptors, we evaluated the effects of anti-HLA class I monoclonal antibodies on beta-adrenoceptor-mediated intracellular production of cAMP in human mononuclear leukocytes. Moreover, we studied whether anti-HLA class I monoclonal antibodies inhibit the binding of a specific radioligand to the beta-adrenoceptors, and, conversely, whether both isoproterenol and propranolol interfere with the binding (evaluated by a cytofluorometric assay) of the anti-HLA class I monoclonal antibodies to the cell membrane. Our results showed that anti-HLA class I monoclonal antibodies induced a significant beta-adrenergic-dependent increase in intracellular cAMP whereas anti-HLA class II and antimelanoma monoclonal antibodies were ineffective. Moreover anti-HLA class I monoclonal antibodies inhibited, in part, the specific binding of a beta-adrenergic radioligand, although they did not induce the internalization of the beta-adrenoceptors. On the other hand, both isoproterenol and propranolol induced a significant decrease in the peripheral blood mononuclear cell expression of HLA-class I molecules. Our data suggest that important interactions between major histocompatibility complex gene products and the beta-adrenergic receptors may occur in human cells.

Adult↗
PubMed1992

Norepinephrine-induced plasma dopamine decrease in man: pharmacological evidence of the involvement of alpha 2-adrenoceptors.

OBJECTIVE: The purposes of this study were: (1) to test whether intravenous infusion of norepinephrine can affect plasma dopamine levels; and (2) to explore to what extent dopamine-2 or alpha 2-receptors play a role in this response. DESIGN: Norepinephrine infusion in man was performed to test whether the increase in norepinephrine during sympathetic stimulation can affect dopamine release. Specific antagonists of presynaptic dopamine-2 and alpha 2-receptors were administered to test the receptor(s) involved in this possible regulatory phenomenon. METHODS: Plasma catecholamine levels were investigated in seven normal subjects before and after administration of domperidone (dopamine-2 antagonist), yohimbine (alpha 2-antagonist) and norepinephrine. RESULTS: Both oral domperidone and yohimbine induced a significant increase in both plasma norepinephrine and plasma dopamine. Norepinephrine infusion induced a significant decrease in plasma dopamine. Pretreatment with domperidone only partially counteracted this inhibitory effect of norepinephrine infusion, whereas yohimbine fully counteracted it. CONCLUSIONS: Our data show that norepinephrine may act as a hormone at plasma concentrations as low as 450 pg/ml. The norepinephrine-induced plasma dopamine decrease seems to be alpha 2-adrenoceptor-mediated. This norepinephrine effect may be involved in the physiologic decrease in plasma dopamine that we demonstrated in the upright position in normal subjects.

Administration, Oral↗
PubMed1991

Absence of correlations between plasma catecholamine levels and mononuclear leukocyte beta 2-adrenergic receptors in the elderly.

To assess the effects of aging on catecholamine plasma levels and mononuclear leukocyte (NML) beta 2-adrenergic receptors and on the possible relationships between these two parameters, we evaluated two groups of human subjects: 18 elderly volunteers (age 65-70 years) and 13 young volunteers (age 21-35 years). Norepinephrine plasma levels were significantly higher in the elderly subjects compared to the younger ones (P less than 0.05), whereas plasma epinephrine levels were not different. Also MNL beta 2-adrenoceptor density was significantly higher in elderly subjects (P less than 0.05). The binding dissociation constants were not significantly different. In young subjects there was a significant (P less than 0.02), inverse relationship between receptor densities and plasma norepinephrine levels; this relationship was not present in elderly persons. Our data suggest that the increase in beta 2-adrenoceptors may be due to a compensatory phenomenon, owing to the reduced beta-adrenergic sensitivity observed in the elderly subjects; moreover, the regulation of beta-adrenoceptors by plasma catecholamines seems to be altered by aging.

Adult↗
PubMed1991

Intraindividual variation of beta 2-adrenergic receptors on mononuclear leukocytes and their relationships with endogenous plasma catecholamines in man.

The interindividual and intraindividual variations of both MNL beta 2-adrenergic receptor density and dissociation constant of binding were evaluated in 19 healthy volunteers. In addition the possible relationships between catecholamine plasma levels and MNL beta 2-adrenergic receptor density were studied in 8 of these subjects. The volunteers were studied three times with ten days' interval. There was a significant inverse relationship between receptor density and norepinephrine plasma levels, only. Neither epinephrine nor dopamine were correlated with receptor density. Interindividual coefficient of variation was 29.57%. The mean value of the intraindividual coefficients of variation was 14.1%, while the mean value of the analytical coefficients of variation was 10%. Our results are at some variance with data in the literature and may contribute to elucidate the role of MNL beta 2-adrenergic receptors as an index of sympathetic function in man.

Adult↗
PubMed1990

Plasma dopamine response to sympathetic activation in man: a biphasic pattern.

We studied the plasma catecholamine response to standing and bicycle ergometric tests in 16 normal male subjects. During the standing test (performed in 10 subjects), we observed an early increase in plasma dopamine together with the fast increase in norepinephrine values; in the second half of this test (i.e. from 5 to 10 min of standing), we observed an increase in plasma dopamine levels. During the ergometric test (performed in 6 subjects), we observed a plasma dopamine increase at the maximal exercise; this persisted during the early recumbent recovery phase (6 min), despite the clear-cut decrease of both norepinephrine and epinephrine plasma levels. Our data are not in agreement with previous papers describing a simple increase in plasma dopamine after stimulation. This paper provides no informations regarding the mechanisms of this response of plasma dopamine. Other approaches must be used to study this aspect more directly.

Adult↗
PubMed1989

Free and sulfoconjugated catecholamines in normotensive uremic patients: effects of hemodialysis.

In 9 normotensive uremic patients undergoing chronic hemodialysis, the baseline plasma catecholamines varied widely from low-normal to very high; sulfoconjugated plasma catecholamines were constantly high. A dialysis-induced fall of all sulfated catecholamines and epinephrine was observed. Norepinephrine decreased in 5 patients and increased in 4, with a strong inverse correlation between predialysis norepinephrine and delta norepinephrine (p less than 0.0001). No correlation was evident between clinical parameters (mean arterial pressure, heart rate) and catecholamines (both predialysis and postdialysis). Significant (p less than 0.0001 and p less than 0.0002) inverse correlations between epinephrine and norepinephrine and their sulfoconjugation degree were demonstrated only in predialysis. Our data may support the presence of a uremic autonomic neuropathy and adrenoceptor damage.

Adult↗
PubMed1989

Reversed-phase HPLC separation of plasma norepinephrine, epinephrine, and dopamine, with three-electrode coulometric detection.

We present a method involving minor modifications of previous techniques, in which we use an ion-pair reversed-phase HPLC separation with three-electrode coulometry. Isocratic baseline separations can be obtained in 5 min. The sample preparation procedure, involving extraction with alumina at low temperature, allows good reproducibility (within-run and between-run CVs less than 10%) and improved sensitivity (less than 5 pg of each catecholamine per extract). This method allows approximately 70 low-cost plasma catecholamine analyses to be done in a working day.

Catecholamines↗
PubMed1987

Interaction between morphine, an opioid agonist, and clonidine, an alpha-adrenergic agonist, on the regulation of anterior pituitary hormone secretion in normal male subjects.

In order to investigate the possible interaction between opioid system and noradrenergic system in the regulation of pituitary hormone secretion, the effects of morphine (an opioid agonist, 10 mg i. v.), clonidine (an alpha-adrenergic agonist, infusion of 0.3 mg in 15 minutes) and clonidine + morphine (infusion of the same dose of clonidine beginning 30 minutes before morphine 10 mg i.v.) on anterior pituitary hormone secretion were studied in six normal male volunteers. Morphine alone induced both an increase in TSH and PRL serum levels and a decrease in cortisol serum levels with no changes in GH serum levels. On the contrary clonidine was able to increase GH and TSH levels and to decrease cortisol levels; PRL secretion was not affected. As regards interaction between morphine and clonidine we observed that morphine-induced increase in PRL release was potentiated by clonidine pretreatment; as regards TSH secretion its increase was greater after the administration of the two drugs with respect to the effect of the single drugs. This study, in agreement with our previous data concerning LH secretion, confirms the important link between clonidine and opioid system in neuroendocrine function, too; the possible explanations of our data are discussed.

Adult↗
PubMedDate not supplied

Neuroendocrine effects of interferon alpha 2-a in healthy human subjects.

The acute effects of interferon alpha-2a (3 x 10 IU im) on catecholamine and immunoreactive beta endorphin plasma levels, cortisol serum levels and lymphocyte beta 2-adrenoceptor density were evaluated in ten healthy volunteers. Interferon induced a significant increase in plasma norepinephrine; there was an increased norepinephrine standing response, too. On the contrary, epinephrine standing response was reduced by interferon. Lymphocyte beta 2-adrenoceptors decreased significantly after interferon administration; dissociation constant of binding was unchanged. Cortisol serum levels increased significantly with respect to control test, whereas immunoreactive beta endorphin did not change. These results support the hypothesis of functional relationships between neuroendocrine and immune systems; moreover they may be useful in clinical trials given the administration of interferon alpha in an increasing number of diseases.

Adult↗