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Biomedical subjects

L Boselli

Publications and source records attributed to L Boselli.

53 records · Page 3Linked to original sources
PubMed1989

Right ventricular wall thickness and function in hypertensive patients with and without left ventricular hypertrophy: echo-Doppler study.

The structure and function of the right ventricle in arterial hypertension have been the subject of only a few reports. The present study evaluated the functional and structural changes in both left and right ventricles. Doppler and standard echocardiography were performed in 58 hypertensive patients (33 without and 25 with left ventricular hypertrophy). We concluded that right ventricular wall thickness is significantly increased in hypertensive patients compared with normotensive subjects, and that there is a significant, direct correlation between right and left ventricular thickness. Abnormalities in right and left ventricular filling, characterized by a reduction in early and an increase in late diastolic flow velocity, occur in hypertensive patients, and there is a direct correlation between late mitral and tricuspidal flow velocities and left and right ventricular thickness.

Adult↗
PubMed1989

[Pulsed Doppler evaluation of left ventricular filling in stable and borderline juvenile arterial hypertension].

Left ventricular hypertrophy in hypertensive patients may be associated with changes in diastolic function. To examine whether or not any alteration in left ventricular function is also present in the early phases of hypertension, left ventricular filling was studied using the echo-Doppler method in 30 young mild hypertensive patients, 40 borderline untreated hypertensives and 30 age-matched normotensive controls. Left ventricular wall thickness, left ventricular mass (Dévereux formula) and shortening fraction were measured using M-mode echocardiogram under 2D control. Trans-mitral flow was measured by pulsed-Doppler and the following parameters were derived: peak early (E) and atrial (A) diastolic flow rate, their ratio E/A, the integral of early (Ei) and atrial (Ai) diastolic flow rates and their ratio (Ei/Ai). Our data show that left ventricular mass is greater in mild hypertensive patients than in borderline and normal controls. No differences in left ventricular systolic function were found in the three groups whereas diastolic function changes were present in the hypertensive group: in particular the peak early/atrial flow rate ratio was significantly reduced compared with the other two groups. Therefore, it appears that changes in diastolic function may also be present even in the early phases of mild hypertension.

Adult↗
PubMed1988

Effect on resting blood pressure and blood pressure homeostasis of short-term administration of the alpha 1-adrenergic receptor antagonist, trimazosin, in hypertension.

The effects of trimazosin on blood pressure and cardiovascular homeostasis were studied in 12 subjects with untreated essential hypertension of mild or moderate degree. After a 3-day placebo period, the subjects were given trimazosin at the dose of 50, 100, or 200 mg twice daily (7 am and 7 pm) according to a randomized, double-blind crossover protocol. Each treatment was prolonged for 3 days and separated from the subsequent treatment by a 2-day placebo period. Blood pressure (sphygmomanometry) and heart rate were measured at rest during various laboratory maneuvers on the first and third day of the initial placebo, on the first and third day of the drug periods, and on the second day of the intervening placebo periods. Compared to placebo values, trimazosin caused a reduction in systolic and diastolic blood pressure which was well sustained through the time between the morning and the evening administration of the drug and was accompanied by only a slight tachycardia. the antihypertensive effect was similar in the supine and upright position and in both instances it was greater for the 100 or 200 mg twice daily dose than for the 50-mg twice daily dose. The pressor and tachycardic responses to cold pressor test and to isometric and dynamic exercise were unaffected by the various doses of trimazosin whose antihypertensive effect was therefore similarly evident at rest and during behaviorally occurring blood pressure rises.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Antagonists↗
PubMed1988

Nifedipine does not blunt the aldosterone and cardiovascular response to angiotensin II and potassium infusion in hypertensive patients.

The antihypertensive response of calcium antagonists of the dihydropyridine series, although accompanied by a significant increase in plasma renin activity (PRA), is generally not associated with a comparably significant rise in plasma aldosterone (PA). This has been suggested to be due to the adrenal glomerular cell responsiveness being dependent on calcium entry. To investigate this hypothesis, angiotensin II (AII; 0.15, 0.375, and 0.750 micrograms/min, each step for 20 min) and KCl (30 mmol/50 min) were infused on separate days in 11 hypertensive patients kept at a constant daily intake of 100 mmol sodium and 40 mmol potassium, before and after 1 week of nifedipine treatment (20 mg b.i.d.). Supine blood pressure (BP) was significantly (p less than 0.01-p less than 0.001) reduced after nifedipine treatment; supine PRA increased significantly (p less than 0.01), while PA did not change significantly. No change in plasma potassium level was seen during nifedipine treatment. The dose-dependent mean BP rises induced by AII were slightly blunted during nifedipine treatment, whereas the PRA decreases and the PA rises after the peak infusion were not significantly different before and during nifedipine administration. Potassium infusion had no significant effect on BP, and caused a significant and similar rise in PA before and during nifedipine administration, while PRA decrease was more pronounced after nifedipine treatment. As previously shown in normotensive subjects, and also in hypertensive patients, aldosterone responses to two major stimulants, such as AII and potassium, do not appear to be blunted by treatment with a calcium antagonist.

Adult↗
PubMed1988

[Correlation between arterial pressure at rest and during effort and left ventricular mass in hypertensive patients who were never treated].

A poor correlation has been found between blood pressure at rest and left ventricular mass in the course of several echocardiographic studies on hypertensive patients. The aim of this work was to determine if this finding could be the result of previous antihypertensive therapy, which had been suspended a few weeks previously in most of the studies. In addition, we tested whether blood pressure values during physical exercise correlate with the echocardiographic indices of left ventricular mass better than the values at rest. In our group of 43 patients with mild to moderate essential hypertension who had never been pharmacologically treated, the correlation between both systolic and diastolic blood pressure and left ventricular mass was poor (r = 0.41 and 0.30 respectively). This result suggests that one or more factors other than hypertension may determine the development of left ventricular hypertrophy. However, in 10 patients with left ventricular hypertrophy a more significant correlation was found between cardiac mass and diastolic pressure (r = 0.52), rather than systolic pressure (r = 0.33). This finding supports data indicating that cardiovascular risk is related more to diastolic pressure increments than to systolic pressure. As for blood pressure values during physical exercise, in our study they did not show a better predictivity of ventricular mass than the values at rest.

Adult↗
PubMed1987

Clinical pharmacological and therapeutic considerations in general intensive care. A review.

The application of clinical pharmacological concepts and therapeutic standards in intensive care settings presents particularly difficult problems due to the lack of adequately controlled background information and the highly variable and rapidly evolving clinical conditions where drugs must be administered and their impact evaluated. In this review, an attempt has been made to discuss the available knowledge within the framework of a problem-oriented approach, which appears to provide a more clinically useful insight than a drug-centred review. Following a brief discussion of the scanty data and the most interesting models to which reference can be made from a pharmacokinetic point of view (the burn patient being taken as an example), the review concentrates on the main general intervention strategies in intensive care patients. These are based mainly on non-pharmacological measures (correction of fluid and electrolyte balance, total parenteral nutrition, enteral nutrition, oxygenation and ventilatory management) and are discussed with respect to the specific challenge they present in various clinical conditions and organ failure situations. In addition, 4 major selected clinical conditions where general management criteria and careful use of prophylactic and therapeutic drug treatments must interact to cope with the variety of presentations and problems are reviewed. These include: acute cerebral damage; anti-infective prophylaxis and therapy; cardiovascular emergencies; and problems of haemostasis. Each problem is analysed in such a way as to frame the pharmacological intervention in its broader context of the underlying (established or hypothesised) pathophysiology, with special attention being paid to those methodological issues which allow an appreciation of the degree of reliability of the data and the recommendations which appear to be practiced (often haphazardly) in intensive care units. The thorough review of the published literature provided (up to mid-1986) clearly shows that in this field the quality of randomised controlled and epidemiological studies is rather unsatisfactory. It would be highly beneficial to research and to clinical care if larger multicentric protocols and prospective epidemiological comparative investigations could be carried out to investigate more timely and adequately the variables which determine drug action, and the final outcome in the many subgroups of patients which must be considered in a proper stratification of intensive care unit populations.

Critical Care↗
PubMed1987

Resting and postexercise hemodynamic effects of carvedilol, a beta-adrenergic blocker and precapillary vasodilator in hypertensive patients.

Carvedilol is a recently developed antihypertensive drug that combines in the same molecule a nonselective beta-adrenoceptor blocking effect and a vasodilating precapillary activity. In our study, we have investigated the effects of carvedilol 25 mg b.i.d. on blood pressure, heart rate, and plasma noradrenaline in hypertensive patients at rest and during exercise after acute and repeated oral administration for 7 days. The daily average supine blood pressure of the 12 patients with essential hypertension was 178 +/- 10/107 +/- 3 mm Hg (means +/- SD of 8 measurements in each patient) after placebo and was significantly (p less than 0.01) reduced to 162 +/- 17/99 +/- 8 mm Hg on the first day and to 158 +/- 15/96 +/- 8 mm Hg on the seventh day of carvedilol treatment. Similar values were found in the upright posture. Heart rate was slightly but significantly lowered during acute and repeated administration. The exercise-induced increase in systolic blood pressure was significantly reduced by carvedilol 25 mg b.i.d., while there was a nonsignificant reduction in the tachycardic response. There was a significantly greater rise in plasma noradrenaline during exercise on the seventh day of carvedilol treatment. Carvedilol significantly lowered blood pressure and heart rate at rest and the exercise-induced rise in systolic blood pressure.

Administration, Oral↗
PubMed1986

HPLC of trazodone in serum after microscale protein precipitation.

Trazodone, an anti-depressant medication, is found in serum in the 500-1000 ng/mL range in patients taking therapeutic doses. Because of this relatively high concentration, it has been possible to devise an HPLC assay system using the rapid, convenient microscale procedure described previously by Lam et al. (Clin. Chem. 26, 963 1980) to prepare the sample for chromatography. To 0.1 mL serum were added 0.1 mL acetonitrile and 10 microL of 10% zinc sulfate in water. The mixture was centrifuged and 50 microL of the clear supernatant was injected into a reversed-phase column which was eluted with 65% 0.05 M potassium phosphate-35% acetonitrile, with detection by ultraviolet absorbance at 210 nm. The trazodone elutes in 6 min, clearly resolved from endogenous interferences. The recovery of trazodone added to serum was better than 90%. Peak height was proportional to concentrations in the serum sample from 125 ng/mL to 3000 ng/mL.

Blood Proteins↗
PubMed1986

Viscero-somatic and viscero-visceral reflexes in brain death.

Little is known about spinal visceral reflexes in brain-dead man, although they have been described in experimental animals. In 1983, 25 brain-dead individuals were observed during donor nephrectomy. It was confirmed that some of these donors, without higher centre modulation and not under significant pharmacological influence, had viscero-somatic motor reflexes and viscero-visceral cardiovascular reflexes.

Adolescent↗
PubMed1985

Antihypertensive and water and sodium balance effects of felodipine, a new vasodilating calcium antagonist, in hypertensive patients.

Felodipine, a new dihydropyridine derivative with a selective action on vascular smooth muscle, was investigated in 2 short term studies in hypertensive patients. In the first study, oral administration of felodipine 12.5 mg three times daily in a preliminary tablet formulation for 3 days significantly reduced supine and upright blood pressure with only a slight increase in heart rate and no clinically relevant signs of sodium and water retention. By increasing each dose to 25 and 50 mg three times daily, there was a further, but quite moderate, decrease in blood pressure; however, this was accompanied by an increase in heart rate and a tendency towards a reduction of creatinine clearance and urinary sodium output. In the second study, a new oral formulation containing 10 mg felodipine, administered twice daily for 7 days, was effective in lowering blood pressure without a clinically relevant tachycardia. Following the first dose of felodipine, urinary sodium excretion was slightly increased while potassium excretion showed only minor changes. The new calcium antagonist, felodipine, lowers blood pressure without the clinically relevant adverse reactions commonly related to other direct vasodilator antihypertensive drugs.

Adult↗
PubMed1974

Regional cerebral blood flow and intraventricular pressure in acute head injuries.

Twelve patients who were comatose after head injuries were studied with serial determinations of regional cerebral blood flow, jugular PO(2) tension, and intraventricular pressure. These determinations began a few hours after the injury, and were followed throughout the clinical course. Diffuse derangement of cerebral vasomotor regulation is confirmed after severe head trauma, which may contribute to deterioration and poor prognosis, and which indicates a need for therapeutic maintenance of rich oxygenation, hyperventilation with moderate hypocapnia, and steady blood pressure. Continuous recording of IVP (eventually sensitized by fluid infusion or CO(2) inhalation tests) may give an early indication of the subsequent clinical state and may suggest the need to submit the patients to further investigative and therapeutic procedures.

Acute Disease↗