Search PubMed⌕ Search

Biomedical subjects

J L Bonnet

Publications and source records attributed to J L Bonnet.

At least 37 records · Page 2Linked to original sources
PubMed1999

Biological treatment of whey by Tetrahymena pyriformis and impact study on laboratory-scale wastewater lagoon process.

A procedure based on a biological treatment of whey was tested as part of research on waste treatment at the scale of small cheesemaking units. We studied the potential biodegradation of whey by a protozoan ciliate, Tetrahymena pyriformis, and evaluated the functional, microbiological and physiological disturbances caused by crude whey and the biodegraded whey in laboratory-scale pilots mimicking a natural lagoon treatment. The results show that T. pyriformis can strongly reduce the pollutant load of whey. In the lagoon pilots serving as example of receptor media, crude whey gradually but completely arrested operation, whereas with the biodegraded whey adverse effects were only temporary, and normal operation versus a control was gradually recovered in a few days.

Animals↗
PubMed1999

[Detection and surveillance of left atrial thrombosis by transesophageal echocardiography].

Out of 1,141 successive transoesophageal echocardiographic studies performed prospectively between 01/05/1993 and 31/12/1995, 26 cases of left atrial thrombosis were observed (2.2%); 5 were in the left atrium (20%), 19 in the left atrial appendage (73%) and the thrombi were in both atrium and left atrial appendage in 2 cases (7%). The 26 patients included 15 women and 11 men, with an average age of 69 +/- 16 years (range 25-89 years); 22 patients (84%) had permanent atrial fibrillation and 4 were in sinus rhythm. Only 5 of the patients were on oral anticoagulant therapy. All had underlying cardiac disease: 11 mitral valve diseases; 10 dilated cardiomyopathies; 2 hypertrophic cardiomyopathies; 3 other cardiac diseases. The indication for transoesophageal echocardiography was systemic embolism in 13 cases (50%); before D.C. cardioversion in 10 cases (38%) and before percutaneous mitral valvuloplasty in 3 cases. The thrombus was adherent in 18 cases (69%) and mobile in 8 cases (31%). Spontaneous contrast was observed in 23 cases (88%). Intravenous heparin was given as soon as the diagnosis was made. In 4 patients, thrombectomy was indicated in view of the threatening nature of the thrombus and/or the necessity for associated valve replacement. In 22 patients, heparin was relayed by oral anticoagulants on the 10th day of treatment. Control transoesophageal echocardiography was not performed because of the patient's refusal or poor general condition. The other 15 patients were reexamined 1 to 5 times between the 4th day and 12th month: a regression was observed in 13 cases (86%) which was complete in 11 and partial in 2 cases. No cases of embolism occurred during follow-up but six patients died: 1 of the operated cases and 5 of the patients treated medically (3 cardiac failures and 2 cerebral haemorrhages). The authors conclude that left atrial thrombosis is rare in the absence of classical embolic cardiac disease. With the exception of the surgical indication of a life-threatening thrombus and/or associated surgical mitral valve disease, anticoagulant therapy results in complete or partial regression of the thrombus visualised by transoesophageal echocardiography which is essential for follow-up. The prognosis depends on the severity of the underlying heart disease.

Adult↗
PubMed1999

[Prospective study on the mechanism of myocardial infarction without significant coronary stenosis].

The aim of this study was to evaluate prospectively the respective roles of the atheromatous plaque, coronary spasm and abnormalities of haemostasis in patients with myocardial infarction with normal coronary arteries. The study population included 25 patients (19 men and 6 women) with a mean age of 52.1 +/- 11.1 years (34-76 years). The diagnosis of myocardial infarction was made as the finding of 2 out of 3 WHO criteria. It occurred spontaneously and was transmural in 80% of cases, inferior wall infarction in 9 patients (36%), anterior in 12 (48%) and lateral in 4 patients (16%). All patients underwent investigation on average 10 days after infarction (1-42 days) by coronary angiography with quantitative angiography, endocoronary ultrasonography, an ergometrine provocation test for coronary spasm and a blood coagulation study. Coronary angiography was normal in 4 patients but showed wall changes without stenosis > 50% in 20 patients and one case of aneurysmal arterial disease. Intracoronary thrombosis was detected in 6 cases. Endocoronary ultrasonography confirmed the normality of the coronary arteries in 2 cases and showed atheroma in 23 cases (soft atheroma: n = 17 and hard: n = 6). It detected 66% of the coronary thrombi observed at angiography and found 3 other cases. Coronary spasm was verified in 10 patients (40%). The coagulation study was normal in 19 patients and showed increase in Pai-1 in 5 patients and primary thrombocythemia in one case. The authors conclude that coronary angiographic data is less accurate than endo-coronary ultrasonography which best shows the extent and, above all, the nature of the plaques present in 23 of the cases (92%). Coronary spasm may be a contributing factor in 40% of cases, in situ thrombosis in 36% of cases despite usually normal blood clotting studies. None of these abnormalities was observed in one case. The embolic cause of infarction was certain in 2 cases.

Adult↗
PubMed1999

[Acute complications of coronary angioplasty: prevention and management].

The immediate results of transluminal coronary angioplasty (TCA) have improved considerably during recent years. Balloon dilatation of the arterial stenosis is the basis of this technique of revascularisation but new tools may be used to treat specific lesions. Coronary occlusion is the most feared complication of TCA. It may cause myocardial infarction or death of the patient. It is usually secondary to dissection and/or thrombus of the artery. The implantation of a stent successfully treats most cases of dissection. New anti-platelet (GP IIb/IIIa) drugs seem to be very effective in the prevention and treatment of the thrombosis. The systematic use of ticlopidine limits the risk of stent occlusion. Improved features enable satisfactory implantation of stents in the majority of cases. In some patients, the clinical consequences of occlusion may be limited by vascular bypass techniques, especially intra-aortic balloon pumping. In other cases, emergency coronary bypass surgery may be necessary. When TCA is considered to be a very high risk procedure, effective surgical cover is essential.

Angioplasty, Balloon, Coronary↗
PubMed1998

Circadian variations in minute ventilation can be reproduced by a pacemaker sensor.

Special software allowing the memorization of 24-hour minute ventilation can be loaded into the memory of the Chorus RM, a DDDR pacemaker driven by minute ventilation. This feature was tested in the postimplant period in 13 patients. Measurements of minute ventilation, respiratory rate, and respiratory amplitude were analyzed according to prospectively defined diurnal and nocturnal time periods. Minute ventilation decreased by 39% (P < 0.001) from the diurnal to the nocturnal phase, while respiratory rate and amplitude decreased by 18% and 28%, respectively (P < 0.001 each). Thus, minute ventilation allowed discrimination between sleep and waking hours. This information could be utilized to modulate the backup rate of the pacemaker.

Aged↗
PubMed1998

Automatic adaptation of the basic pacing rate in response to minute ventilation. Chorum French Investigational Group.

Rate responsive pacing based on minute ventilation (VE) correlates highly with metabolic demand. This type of sensing also recognizes extended periods of rest. The Chorum pacemaker includes a rate responsive algorithm that modulates the basic rate according to phases of activity versus sleep. Forty-six patients (mean age 78 +/- 15), received a Chorum pacemaker for atrioventricular block in 17 cases, sick sinus syndrome in 25, and mixed disorders in 4. Holter monitoring was performed to analyze to heart rate and to examine the circadian adaptation of the minimal pacing rate. The mean basic rate was programmed at 63 +/- 5 beats/min, and the sleep rate at 52 +/- 4 beats/min. Seventeen patients had spontaneous heart rates consistently above the programmed basic rate, and 6 had sustained supraventricular tachyarrhythmias. One-half of the patients had periods of pacing at the programmed sleep rate. The mean diurnal pacing rate was 68 +/- 5 beats/min compared to a mean nocturnal rate of 60 +/- 4 beats/min (P < 0.0001). The average time spent at the basic rate was 37 +/- 30 min (0-110) during daytime (4%), versus 242 +/- 153 min (20-477) at night (45%, P < 0.0001). No adverse effect was observed in this patient population. VE allows a reliable detection of the sleeping periods as well as an adjustment of the basic rate in accordance. Caution is advised in cases of bradycardia dependent tachyarrhythmias.

Aged↗
PubMed1998

Measurement of minute ventilation with different DDDR pacemaker electrode configurations. Investigators of a Multicenter Study Evaluating the Chorus RM and Opus RM Pacemakers.

A rate responsive minute ventilation (VE) pacemaker was implanted in 49 patients (70.8 +/- 40.0 years). A Chorus RM 7034 pacemaker was implanted in 43 patients and an Opus RM 4534 in six patients. Four sensor configurations were compared: atrial configuration (bipolar atrial lead) in 34 patients; ventricular configuration (bipolar ventricular lead) in 6 patients; unipolar configuration (double unipolar leads) in 6 patients; and floating configuration (VDD single-pass lead) in 3 patients. The patients carried out 57 exercise tests in all with cardiopulmonary recording (CPX). Real VE and oxygen consumption (VO2) were recorded by the CPX, the VE measured by the sensor (VEsensor) was recorded in the pacemaker memory. The mean correlation between VE and VEsensor was 0.90 +/- 0.08 (P < 0.001) and between VO2 and VEsensor was 0.86 +/- 0.10 (P < 0.001). The mean correlation between VE and VEsensor by configuration type were as follows: atrial configuration = 0.89 +/- 0.08; ventricular configuration = 0.95 +/- 0.05; unipolar configuration = 0.87 +/- 0.14; and floating configuration = 0.88 +/- 0.05. In conclusion, VE may be reliably measured using different electrode configurations. A study conducted in a larger population should allow one to conclude that unipolar electrodes can be used in VDDR, AAIR, VVIR, or DDDR modes to measure VE.

Aged↗
PubMed1998

Evaluation of a dual sensor rate responsive pacing system based on a new concept. French Talent DR Pacemaker Investigators.

The minute ventilation is known to be one of the most physiological indicators of exercise. A curvilinear relationship between VE and the normal sinus rhythm (NSR) has been demonstrated in healthy patients. The aim of this study is to show that a pacemaker based on a VE sensor can reproduce such a relationship. Eighty-one patients received a Talent DR 213 (ELA Medical, Montrouge, France) pacemaker with a third-generation rate responsive algorithm. At 1-month follow-up, the patients underwent a treadmill exercise test, after which three groups were defined: group 1 had 6 patients who were 100% paced throughout the exercise test; group 2 had 10 patients who maintained NSR throughout the test; and group 3 had 12 patients who had cardiopulmonary recording during the exercise test. In group 1 patients, the simulation function computed the simulated rate (sim-rate), which was compared to the sensor-driven rate (SDR). In group 2 patients, sim-rate was compared to the NSR. In group 3 patients, cardiac and metabolic reserves were compared to determine the appropriateness of the rate response to exercise (HRR% vs MR%). The results showed that the mean correlation coefficient between sim-rate and SDR was 0.983 +/- 0.005 (P < 0.001); the mean correlation coefficient between NSR and SDR was 0.92 +/- 0.07 (P < 0.001); and a linear relationship was found between HRR% and MR%, with a mean slope of 1.1 +/- 0.2 that was significantly equal to the theoretical value of 1 (P = NS). In conclusion, combining an activity-driven sensor with a physiological sensor allows the preservation of a physiological rate response during exercise.

Aged↗
PubMed1998

[A quantitative analysis of a predictive model of ambulatory blood pressure monitoring integrating physical activity recording].

OBJECTIVE: To determine how much of the variations of blood pressure during a 24 hour period could be accounted for by a change in activity using an accelerometer to detect the physical activity and establish a predictive model. MATERIALS AND METHODS: 18 healthy subjects (mean age 25 +/- 2 yrs) were studied during daily life (24 hours) twice one week apart. The systolic and diastolic blood pressure, heart rate (HR), and time of measure were recorded by ambulatory monitoring using Spacelabs (4 measures per hour). A portable digital memory device was designed for the 24 hours ambulatory monitoring of HR (ECG) and physical activity. This device consists of an ECG Holter (ELA medical model Cinesis with digital memory) and a three piezoresistive type accelerometer sensors (prototype ELA research) able to record physical activity in the 3 space dimension. RESULTS: The data of the first recording were compared to the predicated values from the application of a logarithmic model of activity to the second recording. The model then predicted 53 +/- 19% of the systolic BP values of the test day. The mean individual difference for a given time period of one hour between the measured and the predicted systolic BP from the model was 1.45 +/- 3.1 mmHg with a range of [-6.9; 3.4 mmHg]. The mean individual systolic BP difference for the same given time period of one hour but without predictive model was 1.29 +/- 10 mmHg with a range of [-28; 43 mmHg]. CONCLUSION: This study show that 3 D accelerometer is an easy tool to program individual model of ambulatory blood pressure variability. The introduction of this qualitative method seems logical in therapeutic trial.

Adult↗
PubMed1998

[Frequency and nature of atheroma at the site of spasm of angiographically normal or subnormal coronary arteries: an endocoronary ultrasonographic study].

Anatomical studies suggest that sites of coronary spasm are subject to early atherosclerosis. Coronary angiography is unable to confirm the lesions or provide information about their nature. On the other hand, endocoronary ultrasound is able to identify and, it is hoped, to determine the frequency and composition of the lesions. Nineteen patients with chest pain and angiographically normal or subnormal coronary arteries were included in a prospective study (16 men and 3 women: average age 53 +/- 10 years). Four patients had spontaneous spasm and in the other 15, spasm was induced by intravenous injection of ergometrine (6 micrograms/kg). After countering the spasm with isosorbide dinitrate, the site of spasm and adjacent segments were examined by endocoronary ultrasound. Localised vasospasm which was stenotic in 14 cases and obstructive in 5 cases, was observed. The ECG was unchanged in 4 cases and showed ST-T segment changes in 15 cases. The artery affected was the left anterior descending in 10 cases, the left circumflex in 2 cases and the right coronary in 7 cases. A plaque of atheroma, defined as significant intimal thickening, was detected in 18 out of the 19 cases. This atheroma was classified as soft in 17 cases and hard in one case. The authors conclude that vasospasm is not only associated with a plaque of atheroma, nearly always suspected at coronary angiography, but also its composition is nearly always soft (lipidic) from ultrasonographic data.

Adult↗
PubMed1996

Coronary artery spasm in patients with normal or near normal coronary arteries. Long-term follow-up of 277 patients.

Most studies on the natural course of coronary artery spasm in patients with normal or nearly normal coronary arteries are based on medium-term follow-up in small populations. The present series includes 277 successive patients with a median follow-up of 89 months (range: 1 to 198 months). There were 206 men and 71 women whose mean age was 53.6 +/- 9.3 years. They were all assessed with coronary arteriography which revealed no stenoses greater than 50%. Spasm was confirmed during the coronary arteriography in 157 patients (56.7%), by a positive provocation test following the arteriography in 113 patients (40.8%), and by an electrocardiogram which showed Prinzmetal's variant angina in seven patients (2.5%). The majority of patients, 264 (95.3%) were treated with calcium channel blockers. At the end of this study: 35 patients (12.6%) were lost to follow-up; 20 patients (7.2% died) including 10 (3.6%) from cardiac causes; 18 patients (6.5%) experienced myocardial infarction in 11 of whom repeat coronary arteriography consistently demonstrated one or more significant stenoses (greater than 70%); 109 patients (39%) had persistent angina, in 52 of whom the severity (more than one episode per month) warranted repeat coronary arteriography which detected significant stenosis in 19 cases; 95 patients (34.3%) were asymptomatic. Multivariate statistical analyses showed that only predictors of major coronary events (death, myocardial infarction or angina requiring repeat coronary arteriography) were systemic hypertension or the finding of minor parietal irregularities on the initial coronary arteriogram. Conclusion. Despite treatment with calcium channel blockers, persistent or recurrent episodes of angina are frequently observed whereas complications such as myocardial infarction or death are rare.

Adult↗
PubMed1996

Combined antiplatelet therapy with ticlopidine and aspirin. A simplified approach to intracoronary stent management.

Intravascular metallic stents are increasingly used in the non-surgical management of coronary atherosclerosis. Despite intensive anticoagulation, subacute stent thrombosis, which usually has serious clinical consequences, and major haemorrhagic complications remain major problems after stent implantation. In addition, conventional management with anticoagulant therapy requires prolonged hospitalization. In a prospective multicentre study, we investigated the efficacy of a combination of two antiplatelet agents, ticlopidine 500 mg daily and aspirin 200 mg daily, without oral anticoagulation after stent implantation. Since November 1993, 529 consecutive patients, in whom 545 vessels were successfully stented with conventional (non-heparin coated) stents have been enrolled. Stenting was performed as a bailout procedure for failed angioplasty in 112 patients, for a suboptimal result after angioplasty in 314 patients, and electively in the remaining 103 patients. Coronary events related, or possibly related, to stent thrombosis occurred in 5.4% of patients stented as a bailout procedure and in 1.8% of patients stented for a suboptimal result. Serious bleeding complications occurred in 5.4% of patients stented as a bailout procedure and 1.5% of patients stented for a suboptimal result. Neither stent thrombosis nor serious bleeding complications were seen in patients stented electively. Ticlopidine therapy was discontinued in 1.9% of patients due to neutropenia (0.6%) or rash (1.3%). Mean hospital stay decreased from 6.16 +/- 2.14 days to 4.2 +/- 2.15 days during the study period. A combination of two antiplatelet agents can be employed in the vast majority of patients after coronary stent implantation. Subacute stent thrombosis rates and bleeding complications compare favourably with those reported using conventional therapy and the duration of hospitalization is reduced.

Adult↗
PubMed1996

Mode switch despite undersensing of atrial fibrillation in DDD pacing.

UNLABELLED: Mode switching algorithms are commonly used to protect the ventricles against high rates induced by atrial tachycardia. In the case of atrial fibrillation (AF), the response of these algorithms depends on the quality of atrial sensing. The Chorum 7234 DDDR pacemaker uses a new mode switching algorithm, based on a statistical analysis of the atrial rhythm. It includes two criteria of diagnosis: "high" if more than 28 of 32 cycles are abnormally accelerated; and "low" if more than 36 of 64 cycles are abnormally accelerated. METHODS: From a taped database of electrophysiological studies, episodes of AF lasting more than 2 minutes were selected. A tape recorder replayed the atrial signals into an external Chorum device. Each episode was replayed eight times with a programmed atrial sensitivity increasing from 0.4-2.0 mV. For each criterion of diagnosis and each programmed sensitivity, the percentage of atrial sensing, the time to switching, and the mean ventricular rate were measured. Ten episodes of AF from 10 patients (9 men and 1 woman; ages 62 +/- 16 years) were included: 1.95 +/- 0.97 mV and 196 +/- 64 ms. The sensitivity of the algorithm to diagnose atrial tachycardia reached 100%, for an atrial sensitivity set between 0.4 and 1.0 mV. The mean percentages of atrial sensed events were 74% +/- 18% and 46% +/- 9% for the "high" and "low" criteria, respectively. The mean diagnostic times were 28 +/- 26 seconds and 68 +/- 27 seconds, respectively. Sensing of < 23% of AF events resulted in failure to diagnose the arrhythmias by both algorithms. In the event of diagnostic failure, the mean ventricular pacing rate was 79 +/- 9 ppm. CONCLUSION: Up to an atrial sensitivity of 1 mV, 100% of AF episodes were diagnosed. The Chorum mode switching algorithms are 100% reliable if > 45% of the AF waves are sensed. In the event of switching failure, the ventricle is protected by an average rate remaining below 80 ppm.

Acceleration↗
PubMed1996

[Pulmonary arteriovenous fistula. A rare cause of dyspnea and cyanosis in an adult].

The authors report the case of a pulmonary arteriovenous fistula presenting with dyspnoea and cyanosis in a young adult. The malformation was situated on the proximal pulmonary vessels and was cured by surgical correction. The diagnostic value of the clinical signs and complementary investigations of this rare conditions, often detected during adulthood, is discussed. The functional tolerance of the condition is often variable. Oxygen desaturation of arterial blood indicates a right-to-left shunt. Pulmonary angiography enables visualisation of the lesions and guides surgical management. The prevalence of complications of this condition is not well known, but the potential severity is an argument for therapeutic intervention. Embolisation techniques are developing but there is a risk of a systemic embolism. Surgery is the reference for the treatment of proximal fistulae, its curative effect being immediate and definitive.

Adolescent↗
PubMed1996

[Abnormal origin of the left coronary artery from the pulmonary artery. Diagnostic contribution of ultrasonographic technique].

We report a case of abnormal origin of the left coronary artery from the pulmonary artery trunk. The original features of this case were its discovery in a young pregnant woman, the normality of basal left ventricular function and the electrocardiogram, the diagnosis by transoesophaegeal echocardiography, and the demonstration of severe myocardial ischaemia by stress echocardiography.

Adult↗