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Biomedical subjects

R Barbe

Publications and source records attributed to R Barbe.

18 recordsLinked to original sources
PubMed2006

[Psychiatry].

During the year 2005 much of the attention was given to the debate on the risk of suicide during treatments with selective serotonin reuptake inhibitors. Our review concludes with a moderate increased risk of suicidal behaviour but not a risk of death by suicide. Caution, not panic, is indicated, particularly for children and adolescents given that, in this age group, benefits of these drugs have not been well established. We also report two synthesis concerning the latest developments in the fields of cognitive psychotherapy for depressive disorders (rather stimulating news) and of pharmacotherapy for borderline personality disorders (no breaking news).

Adolescent↗
PubMed2002

Validation of a continuous penile blood-flow measurement by pulse-volume-plethysmography.

Today, in the assessment of cavernous artery blood-flow, the most commonly used technique is Doppler ultrasound velocimetry (continuous, pulsed, color-coded or power), which is often considered as the gold standard. Plethysmographic techniques and radioactive tracers have been widely used for the assessment of global penis flow variations but are not adequate for continuous blood-flow measurement. A new pulse-volume plethysmographic (PVP) device using a water-filled penile cuff was employed to assess continuous blood-flow measurement in the penis. Simultaneously Doppler velocity was recorded and served as a gold standard. A penile water-cuff is connected through a pressure tube to a three-way tap. The pulse-volume changes in the penile water-cuff are measured by means of a latex membrane placed over one of the three-way taps. The displacements of the latex are recorded by a photoplethysmograph. The third tap is connected to a 5 l perfusion bag placed 30 cm above the penis so as to maintain constant pressure in the whole device whatever the penis volume. Twenty-four volunteers were tested. The Doppler velocity signal and pulse volume of cavernous arteries were measured simultaneously after PGE1 intra-cavernous injection. Blood-flow variations were induced by increasing penis artery compression with a second penile water-cuff used as a tourniquet fitted onto the penis root, and the pressure of which could be modified by a water-filled syringe. The amplitude of the plethysmographic pulse-volume signal and the area under the Doppler velocity signal were correlated. The inter-patient (n=24) correlation ranged from 0.455 to 0.904, with a mean correlation of 0.704 and P<0.0001. PVP measurement by a water-filled cuff was validated by ultrasound velocimetry. This new continuous, non-invasive and easy-to-use technique enables physiological and physiopathological flow-measurement during sleep, under visual sexual stimulation (VSS), or following artificial erection. Simultaneous recording of penile blood-flow by PVP and intra-cavernous pressure (ICP) measured by a non-invasive device will provide fundamental inflow and outflow information in both physiological and pathophysiological conditions, and further enable venous leakage to be assessed by a mathematical model.

Erectile Dysfunction↗
PubMed1998

[Study of the pharmacodynamic activity of daflon 500 mg].

Daflon 500 mg, micronized purified flavonoid fraction, composed of 90% diosmin and 10% hesperidin, possesses venotonic and vasculoprotective pharmacological properties, it reinforces venous tone by prolonging the activity of parietal norepinephrine. The pharmacodynamic properties of Daflon 500 mg were demonstrated by mercury stress gauge venous occlusion plethysmography during a double-blind placebo-controlled trial in 10 women not presenting any venous disease. Venous tone was significantly reinforced by the 1st hour after a single dose of 2 tablets of Daflon 500 mg. This effect persisted for 4 to 24 hours according to the mode of administration. The rapid action of Daflon 500 mg is due to micronization of its active ingredient into particles less than 2 microns, thereby considerably increasing its absorption.

Adult↗
PubMed1988

[The concept of critical arterial stenosis: value of a model of measures obtained by an angiographic method and the Doppler technic before and after transluminal angioplasty of the iliac arteries].

INTRODUCTION: Numerous studies in the literature have proven the fact that a critical size appears during the stenosis evolution. The work presented is a non invasive approach of this value, with correlation to the invasive results. The study was realized on a homogeneous group of 23 arteriopathic patients, selected for iliac artery angioplasty procedure. MATERIAL AND METHODS: Patients selection: twenty-three patients including 24 angioplasty procedures have been selected on a 21 month time study. Invasive data: two measurements are realized during angioplasty: trans-stenotic pressure gradient before and after angioplasty. stenosis calibration: both diameter and section have been calculated on radiological films. Non invasive data: a standard Doppler test is performed on lower limbs. Two parameters are compared with the invasive data: the ascending time of velocity curve at the common femoral level. the systolic pressure index (peripheral pressure/radial pressure). RESULTS: 1) Critical stenosis--invasive techniques (fig. 1): trans-stenotic pressure gradient versus stenotic measurements shaw an hyperbolic correlation. The critical stenotic level is found to be 60% in diameter and 80% in section. 2) Critical stenosis--non invasive techniques: stenotic measurements compared to ascending time (fig. 2) as well as pressure index at rest (fig. 3) shaw the same type of curve. The critical stenotic level is found to be the same than with invasive techniques. DISCUSSION: Some discordant results open the discussion about angioplasty as a "gold standard", specially with a geometrical analysis. Bad precision in non regular stenosis. Hemodynamic consequences of turbulent stenosis are not evaluated. Clinical interest of critical stenotic notion is underlined.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Comparative study of external methods (Doppler, rheography, flow using Xe) and arteriography of the legs, in the evaluation of stenoses. Statistical evaluation by the Kappa test].

On a thirty five homogeneous group of arteriosclerotic patients, the authors study by means of the Kappa test the validity of arteriographic and non invasive techniques data interpretation by two trained observers. Then they compared between the conclusion of these methods again with Kappa test. The viability of arteriographic and Doppler interpretation is good. The comparison between arteriographic and external techniques results needs strong reduction of the arteriographic data in large classifications. Doppler (with distal pressure) is the best of non invasive techniques, the others staying less selective. The good correlation between arteriography and doppler data observed in main arteries is maximum for femoral arteries and decreases in distal arteries mainly because of a poor filling due to proximal lesions.

Angiography↗
PubMed1983

[Iodized contrast media. I. effector action on serum enzymes].

In vitro studies were done to examine the effects of contrast media on blood enzymatic activities. The results observed are very significant: in the most simple cases they result in a competitive or mixed-type type inhibition of these enzymes. In systems which involve two substrates and two products a Bi-Bi ping-pong enzymatic mechanism is transformed in Bi-Bi random enzymatic mechanism.

Contrast Media↗
PubMed1980

Effects of contrast media on circulating blood volume. A comparative investigation of various sites of injection.

Changes in the circulating blood volume following injection of different contrast media and at different sites have been measured in the dog. The results confirm that osmoreceptors in the right atrium play a role for changes in blood volume following injection of a contrast medium. The differential response to individual agents was mainly a function of their osmolality. Atropine appears to moderate the changes.

Animals↗
PubMed1977

Effect of methylglucamine salts of iocarmic and iothalamic acids on hemodynamics, acid-base equilibrium and coagulation.

The effects of electrolytes, osmolality, pH, PaO2, PaCO2, hematocrit, blood volume and coagulation occurring after a rapid intra-aortic injection of a monomer and a dimer (salts of methylglucamine of the iothalamic and iocarmic acids) were compared. The effects of the monomer agreed with previous results but the effects of the dimer differed from those reported in the literature.

Acid-Base Equilibrium↗
PubMed1976

[Current place of neuroleptics in cardiac surgery under extracorporeal circulation. Cardiovascular effects of different combinations].

We have been using narconeuroleptanalgesia for anesthesia in cardiac surgery under extra-corporeal circulation since 1969, and we have carried out about 3,500 anesthetics of this type on the 1st of October 1975. For all these anesthetics, the neuroleptic used was droperidol. The other components were: - in the case of the narcotic, penthiobarbital, then more recently Alfatesine; - in the case of the analgesic, either dextromoramide or phenoperidine or Fentanyl; in the case of the curare derivative, D, tubocurarine, and above all, pancuronium dibromide. The advantages of neuroleptanalgesia for such surgery seemed to us mainly: - greater cardio-vascular stability in patients with a heart lesion; - the possibility of better control of cardiac output, i.e. by fillingor by inotropic drugs, thanks to the relative vasoplegia produced by the neuroleptic. Finally, in a recent study, we attempted to determine the hemodynamic effect of droperidol and its association on various analgesic drugs measuring in a few patients the cardiac output, the peripheral resistances the the circulating blood volume. We will report the preliminary results of this study.

Adolescent↗
PubMed1976

[Is ventricular fibrillation during cardiac surgery a hasard?].

The late consequences of induced ventricular fibrillation electrically non maintained have been analysed in a series of 547 operations under extracoporeal circulation and moderate hypothermia in the adult; the length of the intraoperative period of fibrillation has been found to have no effect upon the mean postoperative left atrial pressure -- itself a sure indicator of left ventricular function. This is equally true of the variations of the factor both in the operated cases taken together, and between the various groups of operated cases. There is no evidence that ventricular fibrillation has a harmful effect when, in addition, a study is made of the postoperative myocardial complications and of the early deaths. The mean duration of ventricular fibrillation does not differ significantly statistically between the group with complications and deaths, and the group with uncomplicated operations and no mortality.

Adolescent↗
PubMedDate not supplied

["Determination of venous hemodynamics". Contribution of air plethysmography].

Plethysmographic techniques based on the variation of a parameter linked to venous stasis, have permitted an approach to venous hemodynamics. The use of a new technique of air-plethysmography, which cold be quantified in volume variation, and permitting to study the progression of the venous stasis from a static as well as a dynamic standpoint, enable us to better assess the overall venous function. The first results obtained in healthy patients, are presented and the advantages of this new technique are discussed.

Humans↗
PubMedDate not supplied

Evaluation of the clinical pharmacological activity of a phlebotonic agent. Application to the study of Daflon 500 mg.

Provided certain methodological precautions are observed, mercury strain gauge venous occlusion plethysmography represents one of the best available function tests in phlebology to evaluate the efficacy of a phlebotonic agent. All physiological and environmental parameters liable to affect venous tone must be determined and controlled before and during the procedure, which is to be carried out in controlled and fully reproducible conditions. Intra and inter-observed reproducibility of results must be checked regularly in each laboratory. The objective character of the parameters assessed (Hmax, delta Vmax, T50, T2p...) does not spare the need for randomized, crossover or comparative, double-blind placebo-controlled trials, as plethysmographic results may show wide variations from one subject to another, and even from one moment to another, in chronic venous insufficiency, depending on the subject's environment and occupation. Furthermore, knowledge of treatment by the observer may affect the validity of the results. Taking into account all of these methodological pre-requisites, the phlebotonic activity of a single dose of Daflon 500 mg in lower limb chronic venous insufficiency was assessed in placebo-controlled clinical pharmacological studies. The following characteristics emerged: (1) significant improvement of venous capacitance, distensibility, and emptying times, as from the 2nd hour following Daflon 500 mg administration; (2) dose-response relationship, with an optimal dose of 2 tablets per day; (3) rapid onset and long duration of action; (4) significant hemodynamic effect on the venous system, whatever the type of venous insufficiency: organic, functional or gestational.

Adult↗