Biomedical subjects

P Bertalero

Publications and source records attributed to P Bertalero.

5 recordsLinked to original sources

PubMed1989

Decreased fibrinolytic response to adrenergic stimulation in hypertensive patients.

The aim of this study was to assess the function of the fibrinolytic system at rest and in response to adrenergic stimulation in patients with stable essential hypertension as compared with normotensives. At rest, essential arterial hypertensives were characterized by increased levels of circulating tissue-plasminogen activator, associated with an increased activity of its specific inhibitor, the PAI-1. After stress, fibrinolytic response was impaired in essential arterial hypertensives despite a greater release of tissue plasminogen activator by endothelial cells. Therefore, the PAI-1 activity may be increased in essential arterial hypertensives not only at rest, but also after stress. This may represent a risk factor for hypertensive patients.

Adult↗

PubMed1989

[Afterload changes in diabetic dysautonomia evaluated using echocardiography].

We have studied echocardiographic morpho-functional alterations in 34 male subjects with diabetes, aged 31-73 years, with and without autonomic nervous system failure. The subjects are grouped following the tests "deep breathing", "Valsalva manoeuver", "lying to standing" and "active standing" in: D-I (10 normal subjects); D-II (16 subjects with parasympathetic failure); D-III (8 subjects with orthosympathetic failure). The D-III subjects showed significantly lower parietal systolic stress (PSS) compared to normal subjects, 115.6 +/- 17.4 vs 163.1 +/- 13.1 10(3) dynes/cm2 (mean +/- 1SD), and significantly lower end isovolumetric systolic stress, 67.8 +/- 7.8 vs 98.6 +/- 7.1 10(3) dynes/cm2 ("afterload" indexes). In D-III group, the subjects with noradrenaline levels greater than 300 pg/ml, with an hypothetical peripheral resistance to noradrenaline (or receptor "down regulation"), showed higher blood pressure levels and higher parietal stress (PSS: 141.3 +/- 25.3 vs 98.5 +/- 20.7 10(3) dynes/cm2; EISS: 74.1 +/- 17.8 vs 63.6 +/- 8.6 10(3) dynes/cm2). Thus, cardiovascular signs of autonomic failure, like the stress index variation, related to a modification of the afterload, may be observable in diabetic patients.

Adult↗

PubMed1989

Cardiovascular responses to physical exercise and tyramine infusion in hypertensive and normotensive subjects.

The aim of our investigation was to assess blood pressure and heart rate variations in 20 essential hypertensive male in-patients (WHO class I and II) and in 20 normotensive healthy volunteers submitted to three provocation tests: isometric handgrip (IHG), bicycle ergometric exercise (BEE) and tyramine infusion (TI) given as i.v. boluses alternating with saline in a single-blind fashion. According to our data IHG induced a comparable rise of systolic BP, diastolic BP and heart rate both in hypertensive and normotensive subjects. BEE, compared with IHG, caused a more significant (P less than 0.01) rise in SBP and heart rate in both groups. By contrast, DBP during BEE was significantly increased in hypertensive (P less than 0.01), but slightly decreased in normotensive subjects (P = NS). TI caused a dose dependent SBP rise in both groups studied, while DBP and HR were unaffected. BP elevation was, however, more marked in hypertensive subjects. Confirming this finding significantly lower tyramine doses were required to produce the same SBP increase in hypertensives than in the normotensive volunteers. In short, SBP rise during TI and DBP rise during BEE may be the markers of an enhanced cardiovascular reactivity of hypertensive subjects. Our study suggests that BP reactivity to stress may be different according to the laboratory stress employed and also that BEE and TI are more useful than IHG for the assessment of an enhanced cardiovascular response to stress in hypertensive subjects.

Adult↗

PubMed1986

Platelet content of serotonin and response to stress.

As a source of peripherally available vasoactive agents, platelets may play a role in many cardiovascular events. This study aimed to assess the functional role of serotonin released by platelets in mediating the effects of sympathetic stimulation on vascular tone in healthy subjects. Platelet serotonin (5-HT) content and plasma catecholamine concentrations were measured by high performance liquid chromatography with electrochemical detection in blood samples drawn from 10 healthy subjects undergoing tilt test, cold pressor test, treadmill and isometric exercise by handgrip. It was possible to identify both responder subjects who showed a significant decrease in 5-HT platelet content and non-responder subjects who showed no significant change. Stress-induced increases in plasma catecholamine levels were higher in the responders. This suggests that some subjects were more susceptible to adrenergic stimuli and that the elevated concentrations of circulating catecholamines may induce platelet activation and 5-HT release. Analysis of the cardiovascular responses to the tests suggests that 5-HT released by platelets upon adrenergic stimulation in healthy subjects might induce a vasodilatory response modulating sympathetic tone.

Adult↗

PubMedDate not supplied

[Blood pressure changes induced by physical exercise and tyramine infusion in hypertensive and normotensive subjects].

The aim of our investigation was to assess blood pressure (BP) and heart rate (HR) variations in 20 essential hypertensive male inpatients (WHO class I and II) and in 20 normotensive healthy volunteers submitted to three provocation tests: isometric handgrip (IHG), bicycle ergometric exercise (BEE) and tyramine infusion (TI) given as i.v. boluses with saline in a single-blind manner. According to our data, IHG induced a comparable rise of systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate in both hypertensive and normotensive subjects. BEE, compared with IHG, caused a more significant (p less than 0.01) rise in SBP and heart rate in both groups. By contrast, DBP during BEE increased significantly in hypertensive (p less than 0.01), but decreased slightly in normotensive subjects (p = n.s.). TI caused a dose dependent SBP rise in both groups studied, while DBP and HR were unaffected. BP elevation was, however, more marked in hypertensive subjects. Confirming this finding, significantly lower tyramine doses were required to produce the same SBP increase in hypertensive patients than in the normotensive volunteers. In short, an SBP rise during TI, and a DBP rise during BEE may be the markers of enhanced cardiovascular reactivity on the part of hypertensive subjects. Our study suggests that BP reactivity to stress may be different according to the laboratory stress employed and also that BEE and TI are more useful than IHG for the assessment of enhanced cardiovascular response to stress in hypertensive subjects.

Adult↗