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Biomedical subjects

F Perret

Publications and source records attributed to F Perret.

28 records · Page 2Linked to original sources

Need for plasma angiotensin measurements to investigate converting-enzyme inhibition in humans.

Since only a minute proportion of total angiotensin-converting enzyme (ACE) is present in plasma, the reliability of conventional in vitro measurements of ACE activity has been questioned. Data presented here demonstrate that the definition of ACE inhibition depends on the methodology used, with different results obtained with different substrates. We have developed a method that provides accurate and precise determinations of "true" angiotensin levels and in vivo ACE activity was estimated by measuring the plasma angiotensin II/angiotensin I ratio. Since the initial interruption of angiotensin II production by an ACE inhibitor stimulates renal renin release, the response can be quantitated by measuring changes in plasma levels of angiotensin I. The actual state of the renin-angiotensin system during ACE inhibition is represented by the plasma angiotensin II level. When ACE inhibition is no longer complete, increased angiotensin I levels bring the system back toward initial angiotensin II concentrations.

Administration, Oral↗

Effect of cold pressor test on the internal diameter of the radial artery.

The aim of this study was to investigate in normal subjects the effect of a cold pressor test on the caliber of the radial artery, a muscular artery of medium size. The internal diameter of this artery was measured continuously using a recently developed ultrasonic device. Immersion of one hand in ice water for two minutes increased blood pressure from 115/75 +/- 3/2 (Mean +/- SEM) to 136/90 +/- 6/2 mm Hg (P less than .001) and decreased the internal diameter of the radial artery from 2.82 +/- 0.12 to 2.60 +/- 0.09 mm (P less than .01). These data therefore indicate that the vasoconstriction induced by the cold pressor test involves not only arterioles, but also medium-size arteries.

Adolescent↗

Ambulatory blood pressure measurement and antihypertensive therapy.

The traditional basis for assessing the effect of antihypertensive therapy is the blood pressure reading taken by a physician. However, several recent trials have been designed to evaluate the blood pressure lowering effect of various therapeutic agents during the patients' normal daytime activities, using a portable, semi-automatic blood pressure recorder. The results have shown that in a given patient, blood pressure measured at the physician's office often differs greatly from that prevailing during the rest of the day. This is true both in treated and untreated hypertensive patients. The difference between office and ambulatory recorded pressures cannot be predicted from blood pressure levels measured by the physician. Therefore, a prospective study was carried out in patients with diastolic blood pressures that were uncontrolled at the physician's office despite antihypertensive therapy. The purpose was to evaluate the response of recorded ambulatory blood pressure to treatment adjustments aimed at reducing office blood pressure below a pre-set target level. Only patients with high ambulatory blood pressures at the outset appeared to benefit from further changes in therapy. Thus, ambulatory blood pressure monitoring can be used to identify those patients who remain hypertensive only when facing the physician, despite antihypertensive therapy. Ambulatory monitoring could thus help to evaluate the efficacy of antihypertensive therapy and allow individual treatment.

Antihypertensive Agents↗

Non-invasive measurement of internal diameter of peripheral arteries during the cardiac cycle.

An ultrasonic device was developed for continuous monitoring of the internal diameter of human peripheral arteries. The diastolic internal diameter of the radial artery measured in 10 supine normotensive subjects averaged 2.36 +/- 0.12 mm (mean +/- s.e.) and the change in diameter during the pulse wave was 0.037 +/- 0.003 mm. It was surprising to find that when the transducer was used to apply pressure on the radial artery, the difference between the systolic and the diastolic diameter was significantly increased while the diastolic diameter was reduced. This method therefore allows continuous, accurate and non-invasive measurement of the internal diameter of the human radial artery.

Arteries↗

A French double-blind crossover study (danazol versus placebo) in the treatment of severe fibrocystic breast disease.

The Authors report their experience in a double-blind, crossover study (danazol versus placebo) in 38 patients suffering from severe benign mastopathy. The results were evaluated with regard to clinical data (mastodynia, breast nodularity) and data from comparative infrared thermography. Danazol was given in a dose of 400 mg/day for 3 months. Placebo, in identical packing, was also given for a three month period. In 32 cases out of 38, there was an improvement with Danazol treatment. For some patients, thermography was more precise than clinical part. Side effects consisted predominantly of menstrual disorders recorded in 30 cases and a generally moderate weight gain in 23 cases. In the light of these results it appears that danazol constitutes a powerful agent in the treatment of severe benign mastopathy of the breast. The best dosage and best duration of treatment remain to be specified. Finally, the original contribution of the thermographic document deserves to be underlined.

Adult↗