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Biomedical subjects

P Bonnin

Publications and source records attributed to P Bonnin.

At least 19 recordsLinked to original sources
PubMed1999

Cricohyoepiglottopexy: long-term results in 55 patients.

Near total laryngectomy with cricohyoepiglottopexy (CHEP) allows cure of glottic carcinomas with voice preservation. The subject of this study was to evaluate CHEP in terms of tumour control and functional result in T1 and T2 glottic carcinomas. This study reviewed retrospectively 55 consecutive cases of CHEP performed between January 1, 1981 and September 1, 1992 with the exclusion of post-radiotherapy salvage surgery. CHEP was indicated for a T1a limit to the anterior commissure and/or with dysplasia of the other vocal fold (10 cases), T1b (11 cases) and T2 (34 cases) glottic carcinomas. All our patients have a follow-up of more than five years. The post-operative course after this surgery was generally uneventful. The median time to decannulation was 18 days, to removal of the nasogastric tube was 15 days and to discharge from hospital was 23 days. No significant difference was observed according to the preservation of one or both arytenoid cartilages. The long-term functional result can be considered to be good in three-quarters of cases, with normal oral swallowing and an easily understood voice. The remaining one quarter had a whispery voice and sometimes episodes of aspiration when swallowing liquids. In terms of oncological results, the five-year recurrence-free survival rate was 94 per cent for T1 and 84 per cent for T2. The ultimate tumour control (taking into account four cases of total laryngectomy) was 94 per cent for T1 and 93 per cent for T2. Primary surgery by CHEP therefore appears to be a good option for early glottic carcinomas. The main problem remains that voice recovery is mediocre in one quarter of patients.

Adult↗
PubMed1999

Role of the hematocrit in a rabbit model of arterial thrombosis and bleeding.

BACKGROUND: A decrease in hematocrit lengthens bleeding time. The authors studied the role of hematocrit variations in an experimental model of arterial thrombosis and bleeding. METHODS: The Folts model was used in 24 rabbits. After anesthesia was induced and common monitors were positioned, the right common carotid artery was exposed and a 60% stenosis was induced. A compression injury of the artery was then produced, which triggered a series of cyclic episodes of thrombosis and clot lysis (cyclic flow reductions [CFRs]). After counting the number of CFRs that occurred in 20 min (CFR1), the animals were assigned randomly to one of three groups (n = 8 in each group): control, hemodilution with rabbit homologous platelet-rich plasma, and hemodilution with gelatin solution and then reinfusion of the shed blood. The effect of hemodilution with replacement by platelet-rich plasma or by colloid was observed by recording the number of CFRs during another 20-min period (CFR2). A third period of observation (CFR3) followed shed blood reinfusion in the gelatin solution group. Ear immersion bleeding time was recorded after each CFR period. RESULTS: In the two experimental groups, the decrease in hematocrit (from 36 +/- 3% to 23 +/- 2% and from 38 +/- 3% to 23 +/- 2%, respectively; mean +/- SD) abolished CFRs (from a median of 4 to 0 and 7 to 0, respectively) and significantly lengthened bleeding time (from 76 +/- 24 s to 114 +/- 36 s and from 84 +/- 37 s to 127 +/- 29 s, respectively). Blood reinfusion in the group that received the gelatin solution caused CFR to reappear (CFR3 = 4). CONCLUSIONS: Decreases in hematocrit reduced the cyclic arterial thrombosis rate and increased the bleeding time in the rabbits in this study. Hematocrit normalization caused thrombosis to reappear.

Animals↗
PubMed1999

Transport of uterine PGF2 alpha to the ovaries by systemic circulation and local lymphovenous-arterial diffusion during luteolysis in sheep.

The theory of countercurrent vascular transfer of PGF2 alpha during luteolysis was examined. In the first experiment, pulmonary clearance of PGF2 alpha was determined to re-examine whether the total amount of PGF2 alpha was degraded in the lungs after one passage. Cardiac output was measured by the Fick method and PGF2 alpha by radio-immunoassay before and after vascular lung supply, using pulmonary catheterization and the interventional radiology method in ten anaesthetized ewes on day 16 of the oestrous cycle. Cardiac output remained stable (7156 +/- 439 ml min-1). Infusion of 5 iu oxytocin resulted in an increase in plasma PGF2 alpha concentrations at 30 min in the uterine vein and the pulmonary and femoral arteries (3811 +/- 806, 224 +/- 55 and 18 +/- 4 pg ml-1, respectively). The PGF2 alpha concentrations decreased exponentially and the half-time decreases were 27 (r = 0.99), 16 (r = 0.99) and 18 (r = 0.98) min, respectively. Pulmonary clearance of PGF2 alpha was estimated at 6338 +/- 451 ml min-1. In a second experiment, an arterio-arterial gradient of plasma PGF2 alpha concentrations was analysed between the proximal and distal segments of the ovarian artery to verify whether the total amount of PGF2 alpha flowing to the ovary was from the local venous-arterial countercurrent pathway. Surgical catheterization techniques were performed on 11 ewes on day 16 of the oestrous cycle. The ovarian arterial blood flow was measured by the implantable Doppler method (8 +/- 1 ml min-1). The maximum plasma PGF2 alpha concentrations in the femoral and distal ovarian arteries were 23 +/- 6 and 42 +/- 11 pg ml-1 (P < 0.05), respectively. Plasma PGF2 alpha decreased exponentially in the femoral artery and the half-time decrease was 26 min (r = 0.98), and in the distal ovarian artery close to the ovary PGF2 alpha decreased linearly and the half-time decrease was 108 min (r = 0.96). Consequently, the arterio-arterial diffusion gradient of PGF2 alpha concentrations was extended to 3 h. These experiments showed that the PGF2 alpha flow rate in the pulmonary artery was 42.275 +/- 10.793 micrograms per 150 min (n = 10) and the systemic arterial PGF2 alpha flow rate was 5.359 +/- 1.658 micrograms per 150 min (n = 10). Therefore, 12% of the PGF2 alpha was not oxidized by the lungs. The proximal ovarian PGF2 alpha flow rate was 6.909 +/- 2.341 ng per 150 min, while the distal flow rate was 21.003 +/- 5.703 ng per 150 min (n = 11). Thus, 33% of the PGF2 alpha was transported rapidly to the ovary via the systemic route, while 67% was transported by slow local countercurrent diffusion, which extended the duration of luteolytic activity to four times that of the PGF2 alpha surge. These results indicate both rapid systemic transport of PGF2 alpha to the ovaries and a slower buffer mechanism involving a local diffusion pathway, rather than a direct countercurrent system.

Animals↗
PubMed1999

[Hypopharyngeal sarcomatoid carcinoma with one time sarcomatous recurrence. A case report].

We report case of a patient with hypopharyngeal biphasic sarcomatoid carcinoma, with two tumor cell component, epidermoid and spindle cells, treated by surgery only. Two years later, recurrence is noted with totally different histologic form, sarcomatous monophasic, with spindle tumor cells and smooth muscle phenotype with immunohistochemistry, looking like primitive leiomyosarcoma of high malignancy degree. Such monophasic sarcomatous forms of sarcomatoid carcinoma, without epithelial tumor component, are deceptive and can be mistaken with primitive sarcoma. That is why discovery of epithelial differenciation signs, with immunohistochemistry or electronic microscopy, is very important. In our case, while the epithelial differenciation in the recurrent tumor is away, previous history of true biphasic sarcomatoid carcinoma in the same anatomic location, allows to assert recurrence of the same tumor with monophasic sarcomatous expression and smooth muscle phenotype in this case. Therefore in front of "sarcoma of the upper aerodigestive tract", of any immunohistochemical phenotype, monophasic sarcomatous form of epidermoid sarcomatoid carcinoma have always to be evocated and searched.

Aged↗
PubMed1998

Ketorolac and enoxaparin affect arterial thrombosis and bleeding in the rabbit.

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) may interfere with hemostasis during the perioperative period, and the combination of NSAID and enoxaparin could increase this effect. The aim of this prospective, blinded experimental study was to assess these effects using a model of arterial thrombosis and bleeding in the rabbit. METHODS: After anesthesia was induced and monitors placed, the common carotid arteries were exposed, and 60% stenosis of the right common carotid artery was produced. Twenty minutes later, a compression injury of the artery was produced that triggered a series of cyclic episodes of thrombosis and clot lysis. This was manifested as cyclic flow reductions (CFR; measured with an electromagnetic flow meter). After the first flow reduction was noted, the rabbits were immediately and randomly assigned to one of four groups (n = 10 each) that received intravenous infusions: control, ketorolac (2 mg/kg), enoxaparin (0.5 mg/kg), and ketorolac plus enoxaparin (2 mg/kg and 0.5 mg/kg, respectively). The number of CFRs that occurred in the subsequent 20-min period was used as a measure of treatment effect. The contralateral common carotid artery was exposed, and both stenosis and injury were produced. The ability of the administered drug to prevent thrombosis was assessed as the number of CFRs that occurred during the first 20-min period after vessel injury. In addition, both before and after group assignment and drug injection, bleeding times were noted and a platelet aggregation test was performed. Laparotomy was followed by a spleen section, and the extent of the wound and the amount of splenic bleeding were measured. RESULTS: The treatment effect was indicated by the median number of CFRs, which was 5.5 in the control group, 1 in the ketorolac group, 2 in the enoxaparin group, and 0 in the ketorolac + enoxaparin group. The prevention effect was indicated by the median number of CFRs, which was 4 in the control group, 0 in the ketorolac group, 2 in the enoxaparin group, and 0.5 in the ketorolac + enoxaparin group. Bleeding time was significantly lengthened in the enoxaparin and in the ketorolac + enoxaparin groups. Splenic and wound bleeding was greater in the ketorolac group. Platelet aggregation was completely inhibited in the ketorolac and the ketorolac + enoxaparin groups. CONCLUSIONS: Ketorolac had an important antithrombotic activity. The association of enoxaparin with ketorolac seemed to lengthen the bleeding time observed with ketorolac.

Animals↗
PubMed1998

Circulatory changes induced by isovolumic increase in red cell mass in fetal lambs.

AIM: To verify whether extra uterine changes in total peripheral vascular resistance and cardiac output, caused by raised haematocrit, occur in fetal life and if they can be documented using conventional ultrasound techniques. METHODS: An exchange transfusion with packed red cells was performed on five fetal lambs at 140 days of gestation (weight 3.44, SD 0.48 kg); three others were used as controls. The haematocrit was raised from 44 +/- 3 to 64 (SD2)%. RESULTS: Body temperature, blood gas, and pH remained within normal limits. Blood viscosity increased from 5.3 (0.3) to 9.6 (1.6) cps. Combined cardiac output fell to 30% of its initial value. The pulsatility index (PI) remained unchanged in the umbilical artery (0.66, SD 0.1) and descending aorta (1.3, SD 0.3). A significant positive correlation was found between haematocrit and PI only in the carotid artery (r = 0.67, p < 0.01). CONCLUSION: In the fetus, as in adults, an increase in blood viscosity is associated with a fall in cardiac output. However, the low resistance and the relative inertia of the placental vascular bed blunt the velocimetric changes that could be induced in the lower body vascular system by an increase in resistance. Such changes were observed only in the carotid artery. These results could be of interest in the Doppler monitoring of human fetuses at risk of an abnormal increase in their haematocrit.

Animals↗
PubMed1997

Intra- and extracranial artery blood velocity during a sudden blood pressure decrease in humans.

The intra- and extracerebral Doppler artery blood velocity responses to a 10-mmHg abrupt blood pressure (BP) decrease in ten healthy men were studied. This decrease was obtained using two cuffs placed over both thighs. First, cuffs were inflated to pressures greater than the arterial BP for 5 min. Next, they were deflated to 60 mmHg in order to prevent venous return from the legs. We obtained a decrease in mean arterial BP of from 101 (10) to 90 (10) mmHg [mean (SD), P < 0.01] without modifications in the heart rate [HR, 88 (14) beats min-1]. Middle cerebral artery mean blood velocity (MCAmv) decreased immediately from 50 (10) to 42 (12) cm s-1 (P < 0.05). Simultaneously, temporal superficial artery mean blood velocity (TSAmv) decreased from 11 (3) to 7 (2) cm s-1 (P < 0.05) and common carotid artery blood flow (CCAbf) decreased from 305 (23) to 233 (33) ml min-1 (P < 0.05). After 5 s, MCAmv and CCAbf returned to baseline values, whereas TSAmv [8 (2) cm s-1], mean arterial BP [86 (10) mmHg] remained low and HR increased [92 (12) beats min-1]. TSAmv, BP and HR returned to baseline values in 1 min. These data confirm that cerebral blood flow (CBF) is very rapidly regulated but that blood flow in extracranial territories is not and that it follows the arterial BP changes.

Adult↗
PubMed1997

Evidence of fetal cerebral vasodilatation induced by submaximal maternal dynamic exercise in human pregnancy.

To investigate the relationship between maternal exercise and fetal circulatory responses in humans during the third trimester of pregnancy, changes in uterine, umbilical and fetal cerebral circulations were measured by pulsed-Doppler ultrasound method in 14 healthy volunteer pregnant women before and just after a moderate non-exhaustive exercise. Maternal heart rate increased significantly reaching 80% of the theoretical maximal heart rate (TMHR) while uterine resistance indices did not change. The fetal heart rate and umbilical mean velocity were unchanged while umbilical resistance index decreased slightly (0.58 +/- 0.06 versus 0.62 +/- 0.07, P < 0.05). The fetal internal carotid artery mean velocity increased (23.2 +/- 5.3 versus 20.4 +/- 4.1 cm/s, P < 0.02) and the cerebral resistance index decreased (0.71 +/- 0.11 versus 0.80 +/- 0.10, P < 0.01). We conclude that submaximal maternal exercise at 80% of TMHR does not significantly alter uterine perfusion but involves a slight fetal cerebral vasodilation which could be due to a moderate fetal hemoglobin desaturation.

Adult↗
PubMed1995

Influence of posture on middle cerebral artery mean flow velocity in humans.

We determined middle cerebral artery, common carotid artery and temporal superficial artery Doppler derived flow velocities in ten subjects for 10 min after change in posture. Maximal changes were observed after about 3 min. The 10 degrees head-down tilt position increased blood velocities in the common carotid artery by 13% (SD 4)% (P < 0.001), in the middle cerebral artery by 6% (SD 3)% (P < 0.001) and in the superficial temporal artery by 70% (SD 26)% (P < 0.001). In the standing position, there was an 18% (SD 9)% (P < 0.001) decrease in the common carotid blood velocities, with 14% (SD 6)% (P < 0.001) and 53% (SD 23)% (P < 0.001) reductions in the middle cerebral and superficial temporal artery velocities, respectively. At 9 min after the changes in posture, velocities in the middle cerebral artery were at the value of supine rest, whereas the common carotid blood velocity was not completely restored and deviations in the temporal artery velocity persisted. The data would suggest that cerebral blood flow is regulated with some delay and that such regulation is partially reflected in the common artery blood flow, since changes in a branch of the external carotid artery flow velocity remained.

Adult↗
PubMed1995

Peripheral blood flow responses to exercise after successful correction of coarctation of the aorta.

OBJECTIVES: The purpose of this study was to characterize peripheral flow kinetics in response to progressive discontinuous maximal exercise in 10 patients who underwent repair of coarctation of the aorta and 11 age-matched healthy adolescents. BACKGROUND: An impairment of leg blood flow has been suggested on the basis of exaggerated femoral muscle lactate accumulation in patients with successful repair of coarctation. Few data are available describing blood flow kinetics of the exercising leg in such patients. METHODS: Duplex ultrasound provided transcutaneous measurements of peak systolic and end-diastolic flow velocities of the femoral, humeral and renal arteries at rest and immediately after mild, moderate and maximal exercise intensities for computation of mean velocity, resistance index and femoral blood flow. RESULTS: Femoral mean velocity and femoral blood flow increased linearly with exercise intensity in both groups, but the slope of this increase was significantly lower in patients. Similarly, humeral mean velocity increased significantly less in patients than in control subjects. Femoral resistance index sharply decreased from that at rest (patients [mean +/- SE] 1.4 +/- 0.04; control subjects 1.4 +/- 0.03) to mild exercise intensity in both groups (patients 0.69 +/- 0.03; control subjects 0.72 +/- 0.03). A further decrease was observed at maximal exercise in patients (0.60 +/- 0.04, p = 0.08) but not in control subjects (0.69 +/- 0.02). CONCLUSIONS: These observations suggest that despite a greater exercise-induced femoral vasodilation, patients with successful correction of coarctation of the aorta demonstrate an impaired lower limb blood flow in response to strenuous dynamic exercise. In the absence of stenosis at rest, this alteration could result from exaggerated flow turbulence in the descending aorta distal to the site of correction because of loss of elasticity at the site of the resection of the coarcted segment.

Adolescent↗
PubMed1995

Vasomotor effects of transcutaneous CO2 in stage II peripheral occlusive arterial disease.

Vasomotor effects of skin exposure to carbon dioxide (CO2) have been described in normal subjects. It was of interest, therefore, to determine whether percutaneous CO2 is of therapeutic benefit. In a randomized, double-blind study, 10 patients with lower limb arteriopathy (stage II) were investigated before and after local exposure for twenty minutes to CO2-rich spa gas or to water-vapor-saturated air at the same temperature as that CO2-rich spa gas. Brachial and femoral blood flows, brachial and posterior tibial artery pressures, heart rate, and chest and foot transcutaneous oxygen tensions (tcPO2) were determined. Femoral blood flow, tibial pressure, and foot tcPO2 were significantly increased after exposure of the skin to CO2-rich spa gas. This effect was not accompanied with systemic hemodynamic modifications. Water-vapor-saturated air had no effect. These results suggest that transfer of CO2 across the skin can have beneficial local vasomotor effects in patients with lower limb stage II arteriopathy.

Administration, Cutaneous↗
PubMed1994

Doppler echocardiographic assessment of changes in the central circulation of the fetal sheep induced by maternal oxygen administration.

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.

Animals↗
PubMed1994

Aprotinin could promote arterial thrombosis in pigs: a prospective randomized, blind study.

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)

Animals↗
PubMed1993

Quantitative assessment of circulatory changes in the fetal aortic isthmus during progressive increase of resistance to umbilical blood flow.

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.

Animals↗
PubMed1993

Effects of increased resistance to umbilical blood flow on fetal hemodynamic changes induced by maternal oxygen administration: a Doppler velocimetric study on the sheep.

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)

Animals↗
PubMed1993

Relationship between birth weight and umbilical Doppler blood flow velocity waveforms during the third trimester of pregnancy.

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.

Birth Weight↗
PubMed1992

Comparative arterial antithrombotic activity of clopidogrel and acetyl salicylic acid in the pig.

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)

Animals↗