PubMed Health⌕ Search

Biomedical subjects

G Fleury

Publications and source records attributed to G Fleury.

At least 19 recordsLinked to original sources
PubMed2000

New piezoelectric transducers for therapeutic ultrasound.

Therapeutic ultrasound (US) has been of increasing interest during the past few years. However, the development of this technique depends on the availability of high-performance transducers. These transducers have to be optimised for focusing and steering high-power ultrasonic energy within the target volume. Recently developed high-power 1-3 piezocomposite materials bring to therapeutic US the exceptional electroacoustical properties of piezocomposite technology: these are high efficiency, large bandwidth, predictable beam pattern, more flexibility in terms of shaping and definition of sampling in annular arrays, linear arrays or matrix arrays. The construction and evaluation of several prototypes illustrates the benefit of this new approach that opens the way to further progress in therapeutic US.

Ceramics↗
PubMed1984

Raman spectroscopy and normal vibrations of peptides. Characteristic normal modes of a type-II beta turn.

Raman and infrared spectra have been recorded on the peptide Gly-LPro-Gly-Gly in its zwitterionic form and on its protected homolog Z-Gly-LPro-Gly-Gly-OMe (Z = N-benzyloxycarbonyl and OMe = methyl ester). Both peptides adopt a type-II beta-turn conformation into appropriate solvents, that is in dimethylsulfoxide and chloroform respectively. A normal coordinate treatment has been performed on Gly-LPro-Gly-Gly using a modified Urey-Bradley force field and the characteristic normal modes of vibrations. Their corresponding frequencies have been extracted from experimental investigations.

Amides↗
PubMed1984

Normal modes of vibration of a model peptide adopting the C7 C5 structure. Application toi angiotensin II.

A normal coordinate treatment was performed on the C7C5 conformation using a modified Urey-Bradley force field refined from previous studies on beta-turns. The predicted frequencies were compared with the experimental ones obtained on the peptide hormone human angiotensin II. The existence of both a beta-turn and a C7C5 conformation in solid and in aqueous solution is discussed.

Angiotensin II↗
PubMed1984

[Transcutaneous measurement of blood flow in arteriovenous fistulae caused by hemodialysis using Doppler ultrasound].

Blood flow measurement in arterio-venous fistulae can be performed with a duplex ultrasound system which combines echography and C. W. Doppler. This method is very useful to follow up the patency of the fistulae and his consequence on the cardiac function. The exploration consists in two steps: a qualitative study of the Doppler spectrum to detect a possible decrease of the arterial diastole flow which traduce a severe stenosis; the evaluation of the blood flow in ml/min. The blood flow in ml/mn is a good parameter for the follow-up of the fistulae; moreover in case of high blood flow values, it is very useful to guide the surgical therapy.

Arteriovenous Shunt, Surgical↗
PubMed1983

[Drug addiction by inhalation of gasoline vapor. Clinical and toxicological aspects].

Following an epidemic of sniffing petrol fumes and the death of a child, the authors review published findings of this little-known type of toxicomania. They envisage the Clinical and Toxicological problems. Researching and identifying the petrol remain problems. It is possible to detect the traces of petrol directly in the blood by gaz chromatography on a capillary column coupled to flame ionisation detector but it not possible to identify the product with complete certainly. The gas liquid on a packed column detected by Fournier transformed infra-red spectrography can be given to identification with total accuracy.

Acute Disease↗
PubMed1978

[Restricted myocardial infarction. Coronary angiographic and ventriculographic findings. Comparison with acute coronary insufficiency and transmural infarction].

The findings at coronary arteriography and ventricular angiography in 52 patients with a restricted myocardial infarct were compared with those of 106 patients with acute coronary insufficiency and 100 with transmural infarcts. Certain features place restricted myocardial infarction in an intermediate category when compared with the two other syndromes. The percentage of coronary occlusions was significantly higher in transmural infarction (23.5%) and in restricted infarction (16.6%) than in acute coronary insufficiency 6.8%). Study of the vessel beyond a tight stenosis (greater than or equal to 75% was particularly effective in clearly separating the three groups. As a result, 63% of patients with coronary insufficiency, 40% of these with restricted infarcts, and only 23% of patients with a transmural infarct could be referred for surgery. Ventricular angiography showed a close relationship between restricted infarction and acute coronary insufficiency because ventricular function appeared normal or subnormal (localised hypokinesia) in 69% and 81% of cases respectively, compared with 4% of cases of transmural infarction. Restricted myocardial infarction appears to resemble coronary insufficiency, but shows elevation of enzymes and often more marked disease of distal vessels.

Acute Disease↗
PubMed1978

[Comparison of 24 hours ambulatory electrocardiography and endocavitary recording in the diagnosis of heart rate disorders].

Ninety symptomatic patients aged between 16 and 90 years were investigated by ambulatory continuous 24 hour electrocardiography. 75 of these patients underwent endocavitary exploration of atrioventricular conduction and sinus node function within 48 hour of ambulatory electrocardiography. Symptoms occurred during the recording in 30% patients, enabling the mechanism of the malaise to be determined. Every time that abnormalities in the zone surrounding the Tawara node were demonstrated by endocavitary recordings, the 24 hour electrocardiogramme showed the symptoms to be due to other causes than complete heart block. In 70% patients no symptoms were experienced but 58% of them had cardiac arrhythmias and particularly sinus node dysfunction (24 out of 37 patients) on the 24 hour electrocardiogramme. Comparing the results of these two methods of investigation, continuous electrocardiography appears to be a better technique for the diagnosis of sinus node dysfunction but endocavitary study of sinus node function would seem more suited to determine its severity. Endocavitary recordings seem more reliable in the investigation of paroxysmal atrioventricular blocks. These results demonstrate the complementary nature of these two methods in determining the causes of syncope and dizziness.

Adolescent↗
PubMed1977

[Phonomechanographic evaluation of the severity of pulmonary stenosis].

External phonomechanographic methods allow us to obtain a fairly precise estimate of the degree of obstruction to the pulmonary outflow, whether such an obstruction is a single entity or associated with another intracardiac malformation. The greatest precision in this field is obtained with the cases of pure pulmonary stenosis. The findings on phonomechanographic investigation of 54 cases with pulmonary stenosis have been compared with the results of the haemodynamic tests (catheterisation and angiography) as well as with the anatomical findings after a surgical cure had been effected in a certain number of cases. This study has allowed us to pick out five phonomechanographic criteria of severity of pulmonary stenosis: an increased reduplication of the second sound, lenghening of the interval between the Q wave of the electrocardiogram and the maximum portion of the systolic murmur, an increase in Furuta's ratio and also in the amplitude of the jugular venous a-wave as a function of the total height t (the a/t ratio), but most especially the "corrected" Furuta ratio as a function of the length of the ejection phase of the right ventricle, as this has been shown to possess the best correlation with the right ventricular systolic pressures.

Adolescent↗
PubMed1976

[Indications for prosthetic replacement of the aortic valve].

There is no controversy about the prosthetic replacement of the aortic valve in cases in which there is a disorder of function or cardiac failure, or in cases with a tight aortic stenosis, even if it appears to be well-tolerated clinically. It is especially critical in cases of aortic incompetence with marked cardiac enlargement, but the problems are not overwhelming. The indications for operation in very advanced cases with cardiac failure which is refractory, or in aged patients, are discussed.

Age Factors↗
PubMed1976

[Disorders of sino-atrial and auriculo-ventricular conduction in Steinert's disease. Apropos of one case].

The authors report a case of Steinert's disease with disordered sino-atrial and atrio-ventricular conduction. The presence of sudden syncopal attacks and the absence of a cardiomyopathy (excluded by right- and leftsided haemodynamic studies and coronary arteriography) indicated the insertion of a definitive intra-cavitary pacemaker, especially as the life expectancy of this 54 year old patient did not seem to have been significantly reduced by his disease.

Atrioventricular Node↗
PubMed1976

[Diastolic compliance and indices of contractibility in aortic insufficiency].

A cine-angiographic study was carried out in eleven patients with major aortic incompetence, in two of whom there was an associated aortic stenosis. The ventricular end-diastolic volume is always greatly increased, disproportionately to the modest increase in end-diastolic pressure. The pressure-volume relationship during filling is therefore altered, and makes it possible for a normal end-diastolic compliance (dV/dP) TD to be preserved. The indices of contractility are markedly altered, despite the recent appearance of signs of poor tolerance. These findings argue in favour of a full haemodynamic investigation and of early corrective surgery.

Adult↗