Biomedical subjects
Publications and source records attributed to P Bonnin.
We report 3 cases of head and neck malignant fibrous histiocytoma (MFH). The first case is a xanthomatous subtype of the inferior lip with lymph node metastasis. The two others cases are storiform-pleomorphic MFM of the hypopharynx and Killian area. A summary of actual knowledges about this entity is reviewed.
Eleven fetal sheep were studied to investigate if Doppler echocardiography could document redistribution of blood flow during maternal oxygen administration. Velocities through the pulmonary valve, aortic valve, common brachiocephalic trunk, aortic arch, descending aorta, umbilical and carotid artery were recorded before, during and after oxygen was delivered to the ewe by face mask. Indices of cardiac performance (shortening fraction, velocity of fiber shortening and systolic time intervals) were also obtained. The aortic arch was the only recording site where significant changes in mean velocity related to oxygen administration and withdrawal were demonstrated (p < 0.01). Changes in the velocity waveform suggesting an increase in cerebral vascular resistance during oxygen administration were found in the carotid artery. Thus, using Doppler velocimetry, the carotid artery and the aortic arch (equivalent to the human aortic isthmus) appear to be suitable sites to document changes induced by maternal oxygen administration.
Haemostatic properties of aprotinin could be associated with an increased risk of thrombosis. A randomized, blinded study was conducted to consider the potential thrombogenicity of aprotinin, using the Folts' model on femoral arteries in 12 pigs. The flow variations were measured by a pulsed Doppler in anaesthetised animals. Ear immersion bleeding time was performed. During the first part of the study, a stenosis was performed successively on both femoral arteries, each for a period of 30 min, without prior injury, to assess the integrity of the vessel, and to check that the arteries did not develop cyclic flow reductions (CFR), permanent cessation of flow (PCF) or partial thrombosis, when a stenosis is applied. Then the clamp was released and a bolus of placebo (saline), or aprotinin (4 millions KIU, followed by a continuous infusion of 1 million KIU.h-1), was administered. At the end of the bolus, the second part of the study began. Stenosis was applied to the arteries. If CRF, PCF, or partial thrombosis were observed without prior injury then the infused drug (aprotinin or saline) was considered a prothrombotic drug, and the opposite artery was studied. For each animal, right and left femoral artery segments were fixed and studied (morphologic study). Eighteen arteries were studied. In the aprotinin group, 6 arteries out of 8 developed an unexpected thrombosis, as compared with only 2 out of 10 arteries in the control group (p = 0.02). The morphologic study confirmed the occurrence of thrombosis in 4 out of 7 arteries in the aprotinin group, as compared with only 1 out of 9 in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)
BACKGROUND: This study investigated the effects of impairment to placental flow on flow patterns through the aortic isthmus because in the fetus, this vascular segment is the link between the parallel vascular systems perfused by the left and right ventricles. METHODS AND RESULTS: A progressive increase in resistance to blood flow through the placenta was created in seven exteriorized fetal lambs by mechanical umbilical vein compression. Blood flows were measured in the ascending aorta, pulmonary artery, aortic isthmus, and umbilical artery at baseline and at each compression level. The severity of the levels of compression was determined by changes in the flow profile through the umbilical artery. An increase in placental resistance causing a fall in umbilical blood flow of approximately 50% was associated with a retrograde diastolic flow through the aortic isthmus even though the diastolic flow through the umbilical artery remained forward. Because of the systolic predominance, however, the net flow in the isthmus was forward. With a more severe increase in placental resistance corresponding to a decrease of 75% in umbilical blood flow, the net flow through the isthmus approached zero. A strong positive correlation was found between the umbilical blood flow and the net flow through the aortic isthmus (r = .89). CONCLUSIONS: Variations in Doppler blood flow velocity waveforms and integrals of the aortic isthmus can be used as a sensitive indicator of the state of the umbilical circulation.
A fetal lamb model was used to investigate whether the effects of maternal O2 administration on fetal blood gases and hemodynamics were modified when the fetoplacental circulation was compromised by stepwise compression of both umbilical veins. At basal state, O2 administration increased O2 saturation (SaO2) and the pulsatility index (PI) of the carotid artery Doppler wave form (p < 0.01). The first compression decreased left ventricular output (-21 +/- 16%, mean +/- 1 SD, p < 0.01) and umbilical mean velocity (-22 +/- 28%, p < 0.01) but did not modify carotid pH, SaO2, or the PI in any of the arteries studied. At this level of compression, O2 administration increased carotid SaO2 (p < 0.01) but did not affect carotid PI. After a second compression, left ventricular output and umbilical mean velocity were even more reduced [-39 +/- 21% (p < 0.01) and -53 +/- 23% (p < 0.01), respectively]. With this compression, carotid pH, SaO2, and PI decreased, whereas umbilical and descending aorta PI increased. O2 administration at this level of compression increased carotid SaO2 (p < 0.01) but did not modify carotid PI. Throughout the three stages of the experiment, O2 administration did not affect umbilical PI, descending aorta PI, or umbilical mean velocity. A good linear relationship (r = 0.77, p < 0.001) was demonstrated between left ventricular O2 delivery and carotid PI. Thus, at basal state, O2 administration induced velocity changes compatible with an increase in cerebral vascular resistance.(ABSTRACT TRUNCATED AT 250 WORDS)
OBJECTIVES: The Doppler ultrasound method for recording blood flow velocity waveforms in the fetal umbilical arteries is now widely used as an indicator of fetal well-being. This study was conducted to investigate the impact of umbilical placental resistance level on fetal growth development. METHODS: Maximal flow velocity waveforms were recorded from the umbilical artery in 108 pregnant women including 50 with normal pregnancies, 3 with previous death in utero, and 55 with moderate arterial hypertension corrected by resting only. All the newborn infants had a normal birth weight (BW between the 10th and the 90th percentile for the gestational age at birth). Doppler measurements were performed between 25 to 38 weeks of gestation. The placental resistance index (PRI) derived from blood flow velocity measurements was determined. RESULTS: Data were grouped in two-week intervals according to the age of gestation at Doppler examination. We found an inverse close relationship between BW and PRI which can be described by a linear function of PRI in each interval. BW increased with the decrease in PRI. CONCLUSIONS: Our findings suggest that umbilical placental resistance level determines fetal growth development and birth weight during pregnancies without placental insufficiency.
We investigated the comparative antithrombotic properties of clopidogrel, an analogue of ticlopidine, and aspirin, using the Folts' model on femoral arteries in 22 pigs. On each animal, clopidogrel or aspirin were used to treat the thrombotic process on the left femoral artery and to prevent this process on the right femoral artery. Sequentially: an injury and stenosis were carried out on the left femoral artery; the thrombotic process was monitored with a Doppler during a 30-min observation period for cyclic flow reductions or permanent cessation of flow; after the first cyclic flow reduction occurred, clopidogrel (5 mg kg-1) or aspirin (2.5, 5, 100 mg kg-1) were injected intravenously; if cyclic flow reductions were abolished, epinephrine (0.4 micrograms kg-1 min-1) was injected to try to restore cyclic flow reductions and/or permanent cessation of flow; then injury and stenosis were applied on the right femoral artery. Before and after injection of clopidogrel or aspirin, ear immersion bleeding times and ex-vivo platelet aggregation were performed. Clopidogrel (n = 7) abolished cyclic flow reductions were efficiently prevented, even for two injuries. Basal bleeding time (5 min 28) was lengthened (> 15 min, 30 min after clopidogrel and remained prolonged even after 24 h). ADP-induced platelet aggregation was inhibited (more than 78%). Comparatively, aspirin had a moderate and no dose-dependent effect. Aspirin 2.5 mg kg-1 (n = 6) abolished cyclic flow reductions in 2 animals, CFR reoccurred spontaneously in one animal and epinephrine restored it in a second animal.(ABSTRACT TRUNCATED AT 250 WORDS)
Nineteen women (mean +/- SD: 28 +/- 5 years) with small fetuses relative to gestational age (mean +/- SD: 32 +/- 2.2 weeks of gestation) were referred to our unit for cordocentesis for the determination of fetal karyotyping. Four of these 19 patients had small-for-gestational-age ultrasound-derived measurements under the third centile for gestational age. Fetal blood gases were measured in the umbilical vein. Umbilical artery and fetal internal carotid artery Doppler examinations were performed 15 min before cordocentesis. The results showed a progressive and proportional increase in umbilical artery resistance index with hypoxia (p < 0.001), hypercapnia (p < 0.025) and acidosis (p < 0.005). Moreover, the results showed a progressive and proportional decrease in fetal internal carotid artery resistance index with hypoxia (p < 0.01), hypercapnia (p < 0.01) and acidosis (p < 0.025). Fetal blood gases are therefore related to umbilical circulatory function and cerebral vasodilatation, suggesting fetal vascular redistribution.
The aim of the work was to estimate the possible changes induced by high altitude in the distribution of the common carotid arterial blood flow towards the internal and external carotid arteries. Common carotid blood flow and internal and external blood velocities were measured in 20 lowlanders at sea level, in 5 of them over a 3-week period at 3800 m and in 20 permanent residents of this high altitude. Internal and external blood velocities were recorded with a continuous Doppler and blood flow was recorded by range-gated Doppler velocimeter. Common carotid blood flow was 15% higher in all subjects exposed to high altitude due to a lowering in downstream vascular resistance since systemic blood pressure did not change at high altitude. The increase of blood flow in the common carotid was the result of a rise mainly in the external carotid blood flow.
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Vascular reactivity to heat and cold was studied in 11 normal subjects without vascular disease and in 23 patients with Raynaud's phenomenon (etiologies: Raynaud's disease, scleroderma, thoracic outlet syndrome). The study of hand and digital temperatures and brachial artery blood flow was performed in ambiant conditions (room temperature 23.5 +/- 1 degree C) and after thermal (cold or warm exposure: 10, 33 and 40 degrees C), mechanical and metabolic modifications (with a wrist tourniquet). In these conditions, blood flow was studied at each temperature, before, during and after 3 minutes ischemia of the hand. Analysis of results showed that vasomotricity possibilities were preserved but that responses were not identical. Patients with primary Raynaud's phenomenon, and even more those with scleroderma as well, had reduced brachial artery blood flow after cooling (10 degrees C). After ischemia, maximal blood flow was also reduced. The microcirculatory disease existing in Raynaud's phenomenon limits the vasodilator capacity of hand vessels, but probably more in tissues with vascular lesions. Vasodilation seems to be limited during exposure to low well as high temperatures, but vasoconstriction capacity is not disturbed.
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Ultrastructural study, by Scanning and Transmission Electron Microscopy, of three choroidal melanomas allows us to depict main features and cellular types of melanomas and to discuss our results with precedent studies. One case of balloon-cell tumor shows an unusual (from unknown genesis) substance, intra- or extracellularly located, but always near pigment cells expansions.
Changes in systolic and diastolic blood pressure, heart rate, arterial blood flow and vascular resistance in the arm and in the leg were investigated in 9 healthy volunteers (22-40 years) after oral dosing with bisoprolol 10 mg, propranolol 40 mg, and placebo in a randomized double-blind cross-over study. Arterial blood flow and vascular resistance were determined in brachial and femoral arteries with unimpeded circulation, after exclusion of the hand or foot by placing a tourniquet on the wrist or ankle, and during post-ischaemic hyperaemia. Distal arterial occlusion allows one to isolate a predominantly muscular circulation in the forearm or, to a lesser extent, in the leg. Both active drugs induced a significant fall in heart rate and systolic blood pressure versus placebo with no significant difference between the drugs. Brachial and femoral flow rates were reduced by both drugs probably due to a fall in cardiac output, but the two beta blockers produced different effects on vascular resistance: propranolol significantly increased brachial vascular resistance compared with placebo and bisoprolol, both during unimpeded circulation and during occlusion of the hand by a wrist tourniquet. Bisoprolol had no influence on brachial vascular resistance. Both drugs induced small increases in femoral vascular resistance. The different action on local vascular resistance in the brachial artery territory could be interpreted as the expression of the high beta 1 selectivity of bisoprolol leaving the vascular beta 2 receptors unopposed, whereas non-selective propranolol acts on both beta-adrenoceptor subtypes.
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