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Biomedical subjects

M Dauzat

Publications and source records attributed to M Dauzat.

At least 91 records · Page 5Linked to original sources
PubMed1986

[Argon laser and microarterial soldering].

Fifty Wistar rats were submitted to a carotid end-to-end microanastomosis by means of a Coherent 900 Argon Laser. The laser shots were of 300 mW in power output and 5 sec. in duration with an impact area of 150 microns in diameter. The anastomosis was obtained in 4 min. using on an average 19 impacts. The luminal patency was evaluated through doppler and angiography visualization regularly achieved from day 0 up to 7 months. Light, scanning electron microscopic and ultrastructural examinations revealed that, on day 0, endothelial damages never exceeded 100 microns in width in the vicinity of the anastomotic line. Collagenous denaturation was immediately observed in the media and adventitia. The fusion line became re-endothelialized from day 3 and a collagenous network was always present in the media on day 10. Furthermore a slight fibrosis of the adventitia increased the wall resistance. The patency rate was 76% complications such as disruption and aneurysm were due to the initial technical drawbacks.

Animals↗
PubMed1985

Combined continuous wave Doppler and radionuclide delay methods versus angiography in detection of vertebral basilar arterial obstruction.

Noninvasive diagnosis of vertebral artery disease is difficult, but the combined use of Doppler ultrasonography and dynamic radionuclide studies, with measurement of the carotid-basilar delay (CBD), increases the sensitivity and can indicate the level (cervical or distal) of the lesion. Forty patients with cerebrovascular disease were studied by continuous wave Doppler and CBD and the results were compared with vertebral angiograms. The mean normal CBD value was determined for a control group of 18 patients. Sensitivity and specificity were 87.5 per cent and 75 per cent, respectively, for Doppler alone, and 100 per cent and 60 per cent for combined Doppler and CBD.

Adolescent↗
PubMed1984

[Ultrasound measurement of portal blood flow. Initial results in the study of hemopathies].

Portal blood volume was non invasively evaluated with pulsed Doppler ultrasound coupled with automatic, water path echotomography (U. I. Octoson). This measurement was successful in 18 from 24 normal volunteers, the portal flow values being 14.25+ or -4.5 ml/min/kg. The portal blood flow measurement was possible in 16 from 17 patients with hemopathy. Portal flow volume was greatly increased in 11 cases (more than 23 ml/min/kg), in connection with splenomegalia. It was moderately high in 3 cases, from whom 1 without splenomegalia and 1 splenectomised. Portal flow was normal in 1 case and was reduced in 1 case (with high splenic blood flow, in a patient with portal hypertension due to portal vein compression by adenopathy). Portal blood flow increase seems to be connected with splenomegalia. Manometric portal hypertension seems to be more clearly connected with hepatic invasion by hemopathy.

Adult↗
PubMed1982

Modification of spontaneous activity in primary vestibular neurons during development in the cat.

The spontaneous activity of primary vestibular neurons was studied during postnatal development in the cat. Activities were categorized as regular, intermediate and irregular on the basis of the coefficient of variation. At birth, few regularly firing units were found while the percentage of intermediate and irregular units was high. During development, the percentage of units meeting the criterion of regularity increased steadily with age. At the same time the number of intermediate and irregular units decreased. The average resting rate of all categories of unit showed an increase in firing from birth up to the adult stage, i. e., around the second postnatal month. The mean firing rate of regularly firing units was always higher than the two other categories throughout all the stages of development. These results were compared with similar work performed in the rat.

Acoustic Stimulation↗
PubMed1978

[The doppler effect applied to the study of the vertebral arteries (author's transl)].

Results and correlation with arteriographic findings in 25 cases. The methodological criteria essential to the reliability of this examination are described, as well as the special conditions of recording which may influence interpretation. The respective values for systolic and diastolic circulatory rates obtained on ultrasound curves led the authors to classify the results into five groups. There was satisfactory correlation between the latter and the anatomical data provided by arteriography of the vertebral arteries. Such a quantitative approach provides an assessment of the functionally normal or pathological state of the vertebral arteries and of circulatory assymetry.

Angiography↗
PubMed1976

[An audiometric method for use with children. The cochleo-palpebral reflex can be improved by visual conditioning].

It is possible, even with children and new-born babies, to condition the oculo-palpebral reflex to respond to sound. The apparatus constructed by Messrs. Gasquet and Brun achieves this conditioning on the one hand and, on the other, allows this to be used as a method of visual audiometry. This method generally enables the operator to come within twenty decibels or so of the real threshold compared with the unconditioned cochleo-palpebral reflex threshold. The use of a polygraphic recording technique for palpebral response adds precision to the results of this method, particularly by the demonstration of a phenomenon of anticipation which appears when the conditioning has been achieved. Audiometry by means of conditioning therefore represents an objective technique for detecting deafness in new-born babies.

Audiometry↗
PubMedDate not supplied

Doppler study of fasting and postprandial resistance indices in the superior mesenteric artery in healthy subjects and patients with cirrhosis.

PURPOSE: We assessed the resistance index (RI) in the superior mesenteric artery under fasting and postprandial conditions in healthy subjects and in patients with cirrhosis to determine whether the amount of change in the RI reflects the presence or severity of liver dysfunction. METHODS: Fifteen subjects with normal livers and 27 patients with cirrhosis underwent Doppler sonography of the superior mesenteric artery before and after ingesting a standard meal. The RI at baseline (fasting state) and the postprandial RI were compared between the 2 groups. The fasting RIs and post postprandial RIs changes in cirrhotic patients were correlated with the severity of disease. RESULTS: No difference was found between the baseline RIs in healthy (RI = 0.85) and cirrhotic subjects (RI = 0.84), nor was there a difference in baseline RIs between subgroups of cirrhotic patients according to the severity of liver disease. The RI decreased significantly (p < 0.05) after the meal in both the healthy (13%) and cirrhotic (8%) subjects, but the postprandial decrease was significantly less pronounced (p < 0.05) in cirrhotic patients than in healthy subjects. Among cirrhotic patients, there was no correlation between the postprandial decrease of the RI and severity of liver disease. CONCLUSIONS: The marked decrease in the postprandial RI in the SMA in healthy subjects is generally not seen in patients with cirrhosis, and changes in the postprandial RI do not reliably predict the severity of liver dysfunction.

Adult↗
PubMedDate not supplied

Changes in renal artery resistance after meal-induced splanchnic vasodilatation in cirrhotic patients.

PURPOSE: A relationship between vasomotor tone changes in mesenteric and renal vessels in cirrhotic patients has been suspected but remains controversial. The aim of this study was to assess by duplex Doppler sonography the changes in the circulatory resistance of the renal arteries and superior mesenteric artery (SMA) following meal-induced splanchnic vasodilatation. METHODS: Twenty-seven cirrhotic patients and 15 healthy volunteers with no hepatic or renal dysfunction were prospectively included in the study. The resistance index (RI) of the SMA and of the right and left renal arteries was measured by duplex Doppler sonography before and 30 minutes after ingestion of a standard 400-kcal balanced liquid meal. Values in controls and patients and values before and after the meal were compared, and correlations between RIs, Child-Pugh class (liver function), and creatinine clearance were assessed in cirrhotic patients. RESULTS: The fasting renal artery RI was greater in cirrhotic patients than in controls (p < 0.0001), but there was no difference in fasting SMA RIs. After the meal, there was a significant decrease in the SMA RI in controls (0.85 +/- 0.04 before versus 0.74 +/- 0.03 after meal, p = 0.0001) and in cirrhotic patients (0.85 +/- 0.04 before versus 0.77 +/- 0.04 after, p = 0.0001) and a significant increase in the renal artery RI (0.57 +/- 0.06 before versus 0.62 +/- 0.05 after in controls, p = 0.001; 0.68 +/- 0.07 before versus 0.70 +/- 0.07 after in cirrhotic patients, p = 0.001). No correlation was found in cirrhotic patients between the changes in renal artery RI and the postprandial SMA RI decrease, the Child-Pugh class, or the creatinine clearance. CONCLUSIONS: Meal-induced SMA vasodilatation (RI decrease) is associated with a marked increase in the renal artery RI, worsening the renal vasoconstriction in cirrhotic patients.

Adult↗
PubMedDate not supplied

[Effects of a sequential combination of estradiol valerate and cyproterone acetate on the functional properties of the arterial wall in menopausal women].

Several studies have shown that estrogen replacement therapy protects postmenopausal women against coronary artery disease. This protective effect has been ascribed to the hormone's effect on serum lipids, as well as a direct action on the vascular wall. Concurrent administration of a progestin to protect women from the risk of endometrial hyperplasia may alter the protective effects of estrogen. The aim of this study was to assess the evolution of the endothelial function in postmenopausal women given a sequential combination of oral 2 mg estradiol valerate for 11 days, followed by 2 mg estradiol valerate associated with 1 mg cyproterone acetate for ten days (Climène). Each 21-day sequence was followed by a seven-day treatment-free interval. The women received a three-month treatment course. Thirty-one healthy postmenopausal women participated in the study (median age: 51 years; range: 45-59 years). Flow-mediated dilatation (FMD), a reflection of endothelium-dependent vasomotor function, increased from 8.47% at baseline (range: 4.57-11.02%) to 9.64% (range: 7.07-13.12%) at the end of the first treatment cycle; i.e., a 15% increase over baseline (P < 0.0001). FMD further increased after three treatment cycles to 10.59% (range: 8.09-15.22%); i.e., a 28.6% increase over baseline (P < 0.0001). FMD at the end of the first combined sequence or after the 11 days of estradiol only were similar (delta = 0.25%; range: -2.31-5.81%; not significant). In conclusion, in postmenopausal women, a three-month sequential treatment combining estradiol valerate and estradiol valerate plus cyproterone acetate (Climène) has beneficial effects on endothelial function as demonstrated by the evolution of the FMD. There was no decrease in the effect of estradiol on FMD when cyproterone acetate was added to estradiol.

Arteries↗
PubMedDate not supplied

Social and economical effectiveness of non-invasive vascular examinations in the clinical management of thrombo-embolic disease.

In a retrospective study about the seven past years in our Hospital Center, we found that the number of X-ray venographies increased strongly from year to year until non-invasive examinations (Doppler and plethysmography and Real-time B-mode sonography) were widely used with a high sensitivity and specificity level. A new diagnostic algorhythm was then introduced in the clinical practice, X-ray venography being required mainly when an invasive treatment (thrombectomy, thrombolysis, vena cava interruption...) was planed, but not for the positive diagnosis. Thereafter, the number of X-ray venographies decreased. In that way, the cost of the diagnosis was significantly reduced as were risks and discomfort for the patient.

Cost Control↗
PubMedDate not supplied

Transcranial Doppler sonography for blood flow velocity measurement during pharmacological tests.

Transcranial Doppler sonography, using a 2 MHz pulsed Doppler system, is suitable for non-invasive continuous monitoring of middle cerebral artery blood flow velocity during pharmacological studies. Methodological problems, and factors affecting cerebral blood flow have to be discussed (vasomotor spontaneous changes, intracranial blood pressure, blood viscosity, heart rate, vascular risk factors, etc.). Arguing from a previous study in 28 subjects (11 healthy volunteers, 8 hypertensive patients, 9 patients with middle cerebral artery stenosis), showing the hypotensive action of Nifedipine, without significant decrease of cerebral blood flow in 83% of cases, we emphasize the advantages and limits of this new non-invasive method for cerebral blood flow monitoring.

Aged↗