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Biomedical subjects

A Libretti

Publications and source records attributed to A Libretti.

At least 37 records · Page 2Linked to original sources
PubMed1989

Ticlopidine in the treatment of intermittent claudication: a 21-month double-blind trial.

After a 3-month, single-blind, run-in period, 151 patients with intermittent claudication were randomly allocated to receive the antiplatelet agent ticlopidine (250 mg twice per day) or an identical placebo. One hundred and twenty patients completed the double-blind phase of the trial, which lasted 21 months. The primary analysis was performed according to the "intention-to-treat principle" in all 151 enrolled patients. There was, continuing on from the third month after randomization, a progressive and sustained improvement of the pain-free and maximum walking distances in the two treatment groups that was significantly greater in the ticlopidine group. The ankle-arm systolic blood pressure ratio at rest and after exercise increased in a significant manner in the ticlopidine group only. In a secondary analysis, with exclusion of 25 patients because of protocol violations at selection, consistently significant differences in favor of the ticlopidine group were still observed for maximum walking distance and systolic ankle-arm blood pressure ratio, both at rest and after exercise. No major side effects were reported in the treated group. It is concluded that long-term treatment with ticlopidine improves walking ability and ankle systolic blood pressure in patients with claudication.

Blood Pressure↗
PubMed1989

Balanced 24-hour blood pressure control by angiotensin-converting enzyme inhibitors administered once daily.

Traditional sphygmomanometric measurements may inaccurately reflect the actual blood pressure level over a 24-h period. This is due to several factors which are known to affect cuff blood pressure readings, including the limited number of readings obtainable throughout the 24 h and the alerting reaction and pressor response induced in patients by the presence of the physician. Twenty-four-hour ambulatory blood pressure monitoring has been reported to be superior to isolated cuff blood pressure readings in the diagnostic evaluation of hypertension and in assessing the blood pressure response to treatment. It does not trigger any emotionally induced pressor reaction and is able to provide a dynamic evaluation of blood pressure profiles over 24 h. The latter feature is particularly important in assessing the ability of once-daily antihypertensive treatment to reduce and maintain blood pressure at an appropriate level throughout the 24-h period. Studies to date using ambulatory blood pressure monitoring techniques suggest that once-daily administration of certain ACE inhibitors is capable of providing this long-term control of blood pressure. The 24-h antihypertensive action exerted by once-daily administration of ACE inhibitors is characterized by balanced blood pressure control throughout the day and night, and treatment does not appear to alter the neural mechanisms responsible for cardiovascular homeostasis, as suggested by the fact that these drugs have been shown not to affect 24-h blood pressure and heart rate variability. Furthermore, during administration of ACE inhibitors the sensitivity of arterial baroreceptor control of circulation is unaltered or even enhanced. These observations emphasise the potential importance of long-acting ACE inhibitors in the control of arterial hypertension.

Ambulatory Care↗
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↗
PubMed1988

Defective fibrinolytic response in atherosclerotic patients--effect of iloprost and its possible mechanism of action.

Plasma fibrinolytic activity and tissue-type plasminogen activator (t-PA) were defective in response to venous stasis in five out of ten patients with peripheral occlusive artery disease. Discontinuous infusions of iloprost, a stable synthetic analogue of prostacyclin, restored a normal fibrinolytic response in all five patients but did not induce a parallel increase of plasma t-PA. These findings suggest that in addition to the possible benefits due to its vasodilatory and antiplatelet activity, iloprost may improve the fibrinolytic activity in patients with atherosclerotic disease, providing them with further antithrombotic protection. The profibrinolytic effect of iloprost seems not to depend on its ability to induce vascular t-PA release. Rather, it might be related to its inhibitory effect on PAI release from platelets, endothelial cells and/or hepatocytes. Venous occlusion test represents an easy diagnostic approach to fibrinolytic defects, even if related to arterial disease, and may help select patients who need therapeutic intervention.

Adult↗
PubMed1988

Beta-blockade antagonism of tyramine-induced rise in blood pressure.

The effect beta-adrenoceptor blockade on the pressor response to tyramine has been investigated in 6 healthy volunteers, each submitted to an i.v. tyramine pressor test before and after 7 days of propranolol 40 mg b.d. or indenolol 60 mg o.d. Tyramine was given as i.v. boluses of 1-6 mg, alternating with saline, in a randomized, single blind fashion. Prior to treatment tyramine caused a temporary, dose-dependent increase in systolic and diastolic blood pressure, whilst the heart rate remained unaffected. Both propranolol and indenolol reduced the pressor response to tyramine, as shown by a significant increase in ED15, i.e. the dose of tyramine required to increase systolic blood pressure by 15%.

Adrenergic beta-Antagonists↗
PubMed1988

Platelet activation indices and apolipoproteins in hypertensive patients.

We have studied the platelet activation indices beta-thromboglobulin (beta-TG and platelet factor 4(PF4), triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL) and apolipoprotein (A1, A2, B, C2, C3, E) profiles of 22 untreated essential hypertensive subjects (WHO stages 1 and 2) and 22 controls, to see if there might be some causal relationship between lipoprotein abnormalities and greater platelet activation. The results showed the patients had both greater platelet activation than the controls, as demonstrated by higher plasma beta-TG levels (P less than 0.01) and lower apolipoprotein A2 levels (P less than 0.05). However there were no significant correlations between the platelet activation indices and the plasma levels of apolipoproteins, lipoproteins or lipids in either group.

Aged↗
PubMed1987

Enzymuria in carboplatin nephrotoxicity.

Urinary excretion of N-acetyl-beta-glucosaminidase (NAG) is an early marker of nephrotoxicity. NAG activity was assayed by the fluorimetric method of Leaback and Walker in 17 patients treated (22 courses) with carboplatin (CBDCA, 220-550 mg/m2) before infusion and 24, 48, 72 and 96 h after. Increased excretion of NAG, a sensitive index of renal tubular damage, was observed following 10 of the 22 courses. A transient increase in plasma creatinine and/or abnormal proteinuria was observed in 6 cases. Impaired renal function prior to therapy seems to be a predisposing factor to the nephrotoxicity.

Acetylglucosaminidase↗
PubMed1987

Slow-release metoprolol and nifedipine in essential hypertension: 24 hour noninvasive ambulatory blood pressure monitoring.

To assess the efficacy and tolerability of metoprolol (MET), 200 mg slow release (SR) q.d., and nifedipine (NIF), 20 mg SR b.i.d., 20 mildly to moderately hypertensive outpatients (14 men and 6 women; mean age 41.5 years, range 27-49 years) were studied. After being withdrawn from previous antihypertensive treatments, the patients were given single-blind placebo for 2 weeks and thereafter, in double-blind, randomized sequence, MET and NIF, both for 2 weeks. At the end of each period of the study, blood pressure (BP) was recorded for 24 h using a noninvasive ambulatory BP monitoring device (ICR System) with readings taken every 10 min (from 6 a.m. to 6 p.m.), 15 min (from 6 to 12 p.m.), and 20 min (from 12 p.m. to 6 a.m.). Five patients did not complete the study because of the occurrence of unwanted effects (one patient on MET and four patients on NIF). In the 15 patients who concluded the study both drugs significantly reduced (p less than 0.01), in comparison with placebo, systolic BP (SBP), mean arterial pressure (MAP), and diastolic BP (DBP) throughout the 24 h (MET: -16.9, -11.5, and -8.9 mm Hg; NIF: -12.7, -8.4, and -6.6 mm Hg, respectively). In comparison with NIF, SBP and MAP but not DBP were significantly reduced by MET (p less than 0.01 and p less than 0.05, respectively). We conclude that in our patient population MET was more effective and better tolerated than NIF. A possible explanation could be the relatively young age of the subjects we studied.

Adult↗
PubMed1987

Pharmacokinetic study of intravenous and oral idarubicin in cancer patients.

Idarubicin (4-demethoxydaunorubicin) is a new anthracycline analogue which lacks the methoxyl group at the C-4 position of the aglycone moiety. The present study was undertaken to investigate the pharmacokinetics and bioavailability of idarubicin in man. The drug was administered at 3-week intervals to six patients by both intravenous and oral routes. Doses used were 13-15 mg/m2 intravenous and 45 mg/m2 p.o. Plasma levels of unchanged idarubicin and of its metabolite idarubicinal were assayed by high performance liquid chromatography (HPLC). After intravenous administration the plasma levels of the unchanged drug declined very rapidly reaching the sensitivity limits of the analytical method (1-2 ng/ml) 24 h after dosing. Plasma levels of idarubicinal reached a peak of about 10 ng/ml within two hours then decreased very slowly with a plasma t1/2 of about 2.5 days. After the oral dose of 45 mg/m2, the plasma level patterns of both parent compound and the idarubicinal were roughly similar to those after 15 mg/m2 intravenous except for the obvious difference linked to the absorption of idarubicin. The absorption of oral idarubicin was rapid and, in terms of area under curve of the metabolite, the availability after oral administration can be estimated as about 30% of the dose. The urine findings reflected the plasma situation. The metabolite levels were much higher and longer lasting than those of the parent compound. Urinary recovery after intravenous (16% of the dose in four days) and oral administration (approximately 5% of the dose) confirmed the 30% absorption estimated on the basis of plasma levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1986

Blood pressure levels in adolescents: the Milan Study.

The relationship between pubertal maturation and blood pressure (BP) was investigated in a cohort of 1,252 adolescents followed for 4 years. Males and females were categorized into two groups (pre and post), according to pubic hair growth (males) and menses onset before or after the age of 12. BP tracking was higher for systolic BP (SBP) than for diastolic BP (DBP), without differences between the two groups of each sex. By multiple regression analysis, initial BP was the major predictor of the final value in all subjects. Body mass index (BMI) annual change was positively correlated to SBP change over time. Analysis of variance showed an increased within-person variability of SBP in pre subjects, with a significant reduction of DBP residual variance at higher initial DBP levels. Our results suggest that early pubertal maturation and high DBP at age 14 years characterize subjects differing at least partially from the general adolescent population in BP determinants.

Adolescent↗
PubMed1986

Plasma beta-thromboglobulin levels and claudication degrees in patients with peripheral vascular disease.

In 30 patients with varying degrees of claudication and 40 normal subjects, plasma levels of beta-thromboglobulin were determined. These were significantly higher (p less than 0.01) in the patients than in age-matched controls; in the control group the beta-thromboglobulin values resulted slightly higher in older subjects. No correlation was found between beta-thromboglobulin and the severity of the vascular disease, assessed on the basis of the pain-free interval on the treadmill.

Adult↗
PubMed1986

Clinical experience with ketanserin in the treatment of hypertension.

Ketanserin (K), a selective and specific S2-receptor antagonist, has been compared with metoprolol (M), a cardioselective beta-blocker, in a double-blind study in order to assess its efficacy and safety in the treatment of essential hypertension. After a placebo run-in period of 4 weeks, hypertensive patients [supine diastolic blood pressure (DBP) greater than or equal to 100 mmHg] were treated with K, 40 mg twice daily (n = 18), or with M, 100 mg twice daily (n = 14). Systolic pressure (SBP) and DBP, both supine and standing, were significantly reduced from the first month of treatment by both drugs and remained stable for the whole study period (12 weeks). About two-thirds of the patients treated with K responded to the therapy (drop in DBP of at least 10%) and half were normalized (DBP less than or equal to 90 mmHg). In the M group, 50% of patients responded and 30% were normalized. A significant decrease in the heart rate was observed with M, but not with K. Ten patients treated with K were followed for 1 year. The antihypertensive effect of K was maintained throughout the study with evidence of tolerance. No serious adverse reaction was observed.

Double-Blind Method↗
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↗
PubMed1986

Treatment of claudication with dipyridamole and aspirin.

The effects of dipyridamole in association with acetylsalicylic acid were compared with the effects of acetylsalicylic acid alone in patients with peripheral vascular disease. The following parameters were studied in each patient: symptoms-free interval on the treadmill, ankle-arm arterial pressure gradient, oscillographic index, venous occlusion plethysmography and any untoward reactions. Changes were observed in the pain-free interval (p less than 0.005), and in the venous occlusion plethysmography (p less than 0.001) in the patients treated with the two drugs in association.

Adult↗