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J Favre

Publications and source records attributed to J Favre.

At least 37 records · Page 2Linked to original sources
PubMed1996

TRYPNET. New hemoparasite information network.

Although Guyana, Suriname, and French Guiana share borders and climatic and geographic similarities, the countries have maintained little contact, due to language, political, and administrative differences. In 1993, two international organizations involved in the improvement of animal health, the Inter-American Institute for Cooperation on Agriculture (IICA) and CIRAD-EMVT (Centre de Cooperation Internationale en Recherche Agronomique pour le Developpement-Elevage et Medecine Veterinaire des Pays Tropicaux), jointly developed a collaborative project between the veterinary services of the three countries entitled "Hemoparasite Network for the Guianas." This project seeks to pool livestock, laboratory, and technical resources between the three countries in order to generate and exchange information on hemoparasites of livestock. A Hemoparasite Reference Laboratory for the Guianas has been created at the CIRAD-EMVT laboratory in Cayenne, French Guiana. Besides processing ruminant serum samples from the three countries, specialists from this organization conduct training in hemoparasite diagnostic techniques for laboratory personnel from Guyana and Suriname. A large-scale epidemiologic study of hemoparasites of cattle in the three countries is under way, to determine the prevalence, distribution, and clinical and economic significance of hemoparasites in the three countries, particularly Trypanosoma vivax and T. evansi. Preliminary results are presented and discussed. A Hemoparasite Information Network (TRYPNET) has been initiated, including a quarterly hemoparasite newsletter (TRYPNEWS), published in English and Spanish and disseminated to researchers in the Americas, Europe, and Africa. In 1995/96, it is proposed to expand the network's scope to include Venezuela and Brazil.

Abattoirs↗
PubMed1996

Immunoisolated xenogenic chromaffin cell therapy for chronic pain. Initial clinical experience.

BACKGROUND: Chromaffin cells from the adrenal gland secrete a mixture of compounds that have a strong analgesic effect, especially when administered intrathecally. Many studies in animal models have shown that discordant xenogeneic cell isolates, including chromaffin cells, can survive and have biologic effects when transplanted within a semipermeable membrane capsule. METHODS: To evaluate the clinical potential of encapsulated cell therapy, a human-scale implant containing bovine chromaffin cells was developed, characterized, and implanted in the subarachnoid space of seven patients with severe chronic pain not satisfactorily managed with conventional therapies. Patients received no pharmacologic immunosuppression. Cell devices were implanted during minimally invasive surgery, and device design allowed retrieval. All devices were recovered after implant periods of 41 to 176 days. RESULTS: Postexplant histologic analysis, immunostaining, and secretory function all confirmed survival and biochemical function of the encapsulated cells. Reductions in morphine intake and improvement in pain ratings were observed in several patients. CONCLUSIONS: This study represents the first successful trial of encapsulated xenogeneic cells in humans. The preliminary findings of pain reduction warrant the initiation of a randomized, double-blind phase II study to evaluate the potential efficacy of the procedure.

Adult↗
PubMed1996

Pallidotomy: a survey of current practice in North America.

Twenty-eight centers completed a survey about their current practice of pallidotomy. This sample represents a non-exhaustive survey of the current practice of pallidotomy in North America and is not a study of outcomes. 1015 patients underwent 1219 pallidotomies: 811 (80%) unilateral, 72 (7%) staged bilateral, and 132 (13%) simultaneous bilateral. Pallidotomy has long been an accepted procedure and the indications for this surgery, in the opinion of the responding centers, were rated on a scale of 1 (poor) to 4 (excellent) and demonstrated dyskinesia as the best indication (median = 4); on-off fluctuations, dystonia, rigidity, and bradykinesia as good indications (median = 3); and freezing, tremor and gait disturbance as fair indications (median = 2). Most centers used MRI alone (50%) or in combination with CT scan (n = 6) or ventriculopathy (n = 5) to localize the target. The median values of pallidal coordinates were: 2 mm anterior to the midcommissural point 21 mm lateral to the midsagittal plane and 5 mm below the intercommissural line. Microrecording was performed by half of the centers (n = 14) and half of the remaining centers were considering starting it (n = 7). Main criteria used to define the target included the firing pattern of spontaneous neuronal discharges (n = 13) and the response to joint movement (n = 10). Most centers performed motor (n = 26) and visual (n = 23) macrostimulation. Twenty four centers performed test lesions using median values of 55 degrees C temperatures for 30 s. Final lesions consisted of 3 permanent lesions placed 2 mm apart, each lesion created with median values of 75 degrees C temperatures for 1 minute. Median hospital stay was 2 days.

Brain Mapping↗
PubMed1996

Functional anatomy of the pallidal base in Parkinson's disease.

OBJECTIVE: The purpose of this study is to define the morphology of the boundary between the globus pallidus and the ansa lenticularis (i.e., pallidal base) in humans. This information is important for surgeons who perform pallidotomy. METHODS: Thirty-eight patients with Parkinson's disease underwent pallidotomy using microrecording techniques. The pallidal base was identified by the loss of neuronal single unit activity and by the change in background noise, as analyzed on the audio monitor and by fast Fourier transformation. RESULTS: Three quarters of the patients had an abrupt transition of the background noise from neuronal to axonal activity. One quarter of the patients had multiple successive transitions of the background activity, over a distance of 0.4 to 2 mm (median, 1 mm). CONCLUSION: We conclude that the pallidal base is not a smooth, sharp boundary between the globus pallidus and the ansa lenticularis. We propose two models that define the morphology of the pallidal base. One model depicts the pallidal base as a multifolded boundary that distinctly separates pallidal neurons from ansa lenticularis axons. Another model depicts the pallidal base as an indistinct transitional boundary between the globus pallidus and the ansa lenticularis, which contains axonal fibers intermixed with small clusters of pallidal neurons. We discuss the clinical relevance of these findings.

Adult↗
PubMed1996

Characteristics and somatotopic organization of kinesthetic cells in the globus pallidus of patients with Parkinson's disease.

Information is limited on the characteristics and topographic localization of pallidal kinesthetic cells in patients with Parkinson's disease. The authors analyzed the data from 298 neurons recorded in 38 patients with Parkinson's disease who underwent pallidotomy via microrecording techniques. Sixty-five neurons (22%) responded to passive movement of contralateral limbs. Of 17 kinesthetic cells that were tested in six patients, seven (41%) responded to ipsilateral limb movement as well. Nineteen cells (6%) fired synchronously with tremor. More kinesthetic cells were activated (63%) than inhibited (28%) by movement of single (68%) rather than multiple (32%) joints, and proximal (75%) rather than distal (25%) joints. The lateral globus pallidus externus (GPe) and medial globus pallidus internus (GPi) pallidal segments contained similar proportions of kinesthetic cells, activated or inhibited cells, arm- or leg-activated cells, and cells responding to single or multiple joints. Significantly more kinesthetic cells that responded to distal joints were recorded in GPi compared to GPe segments (p = 0.01). Arm and leg cells had similar characteristics pertaining to activation versus inhibition and responses to single, multiple, proximal, or distal joint movements. Arm and leg cells were somatotopically organized in GPi. Arm cells were clustered at the rostral and caudal segments of GPi and leg cells were clustered centrally. In GPe, leg cells were clustered at the caudal border. No somatotopic organization was identified for activated or inhibited cells; cells that responded to single, multiple, proximal, or distal joints; tremor-synchronous cells; or cells responding to specific joints within somatotopic arm or leg cells. It is concluded that kinesthetic cells provide a roadmap that localizes limb cells during pallidotomy. More studies are needed to identify the clinical significance of the different characteristics of kinesthetic cells.

Adult↗
PubMed1996

Anchoring of deep brain stimulation electrodes using a microplate. Technical note.

The authors report a new technique to anchor deep brain stimulation electrodes using a titanium microplate. This technique has been safely used to secure 20 quadripolar deep brain stimulation electrodes implanted for movement disorders (18 electrodes) and pain (two electrodes). Twelve electrodes were implanted in the thalamus, four in the subthalamic nucleus, and four in the pallidum. No electrode migration or rupture occurred, and all electrodes have been shown to work properly after internalization of the system.

Brain↗
PubMed1994

Robot for CT-guided stereotactic neurosurgery.

At the 1989 meeting of the World Society for Stereotactic and Functional Neurosurgery in Maebashi, the authors presented the concept and design of a stereotactic neurosurgical robot. The first prototype has now been completed and has entered clinical testing. The characteristics are as follows. The robot is positioned behind the CT scan and operates inside the CT gantry. It is linked to the CT table and moves freely along its longitudinal axis, allowing for intraoperative scanning at any cranial level. The patient's body rests on the CT table, but the stereotactic headframe is fixed to the robot, allowing precise measurements of the head position under stereotactic conditions. During scanning, each CT slice appears immediately on the robotic workstation for selection of target and trajectory. In addition to the tool for automatic penetration of the skin, skull, and meninges, the robot is able to handle two other stereotactic instruments and to perform a complete stereotactic procedure without physical intervention by the physician. So far, depth electrodes and biopsy instruments have been developed for use by the robot. Since all parts of the robot were designed solely for stereotactic neurosurgery, integration of safety aspects was optimized. The first operations using an aspiration biopsy probe were successfully performed on 2 patients with malignant intracerebral cystic lesions on September 4, 1993.

Humans↗
PubMed1993

Pilocytic cerebellar astrocytoma in adults: case report.

A case of cerebellar pilocytic astrocytoma is reported. This tumor occurs typically in the first two decades of life and is seldom reported in adults. The 42-year-old patient presented with occipital headaches, nausea, and unsteady gait. Nystagmus and right dysmetria were noted. A CT scan showed a hypodense, nonenhancing, voluminous, right hemispheric cerebellar cyst. Magnetic resonance imaging showed a nodule in the wall of the cyst which became hyperintense with gadolinium. The mass was resected through a small occipital craniotomy. Neuropathological examination revealed a juvenile pilocytic astrocytoma.

Adult↗
PubMed1992

Surgical standby for coronary balloon angioplasty.

OBJECTIVE: To assess the predictability of need for emergency surgery after coronary balloon angioplasty. DESIGN: Nonrandomized intervention study. SETTING: Nonprofit university hospital. PATIENTS: Prior to balloon angioplasty, 1000 consecutive patients were assigned to either the "standby" group (189 patients [19%]) or the "no-standby" group (811 patients [81%]). Patients in the standby group (intervention coordinated with cardiac surgery) included all operable patients undergoing angioplasty of their largest coronary arteries that were not currently or previously totally occluded or collateralized; the no-standby group consisted of the remainder of patients. INTERVENTION: Allocation to coronary angioplasty with or without surgical standby. MAIN OUTCOME MEASURES: Need for bypass surgery, occurrence of myocardial infarction, and mortality from complications of angioplasty. RESULTS: Bypass surgery immediately after angioplasty was done in one patient in each group (standby, 0.5%, vs no-standby, 0.1%). The frequency of infarction was 5% vs 4%, respectively. All eight deaths occurred in the no-standby group (1.0%), but none of them were consequences of a lack of surgical standby. They occurred in situations in which bypass surgery would not have changed the outcome (two cardiac failures late after technically successful angioplasty for postinfarct cardiogenic shock, one in-laboratory rupture of an unrecognized ventricular pseudoaneurysm, and one protamine reaction), secondary to acute problems late after successful angioplasty (two sudden deaths and one vessel occlusion in an inoperable patient), or despite surgery (one patient with left main stem dissection). CONCLUSIONS: Performing roughly 80% of coronary angioplasties without surgical standby did not increase patient risk. Coronary angioplasty without surgical backup, albeit not an ideal setting, appears ethically feasible in selected patients if dictated by logistic considerations.

Adult↗
PubMed1992

Magnum system for routine coronary angioplasty: a randomized study.

The Magnum system, initially designed for coronary angioplasty (PTCA) of chronic total occlusion, consists of a balloon catheter and a solid steel 0.021 inch (0.53 mm) steerable and removable wire with a soft and moldable distal portion, tipped with a 1 mm olive. To evaluate its performance in routine PTCA, 200 unselected consecutive patients were randomized to two equal groups, i.e., group Magnum (100 patients, 115 vessels) and group Standard (100 patients, 118 vessels) including 18 and 21 patients with chronic total occlusions, respectively. Randomization was performed by the sealed envelope system in the catheterization laboratory and crossover of system was imposed if it was not possible to place a balloon correctly within 20 min of fluoroscopy time. There were no significant differences between groups concerning clinical and angiographic baseline characteristics, size of initial balloons (3.0 +/- 0.3 mm in both groups), fluoroscopy time to cross the lesion with the wire (Magnum: 4 +/- 5, Standard: 5 +/- 6 min), total fluoroscopy time (Magnum: 11 +/- 9, Standard: 12 +/- 12 min), and need for crossover (Magnum: 10%, Standard: 16%). Success rates per lesion were comparable with 90% in group Magnum and 84% in group Standard, as were the complications with one inhospital death in group Standard, occurring three weeks after PTCA and stent implantation. There was no emergency operation. Six patients per group had myocardial infarction of whom two in group Magnum and one in group Standard developed a Q-wave. The following variables were significantly in favor of the Magnum system compared with the Standard system: success rate in nontotal lesions (97% versus 90%) crossover success in total occlusions (0 vs. 33%), fluoroscopy time to cross the lesion with the balloon once the wire was in place (1 +/- 2 vs. 2 +/- 4 min), and use of a single versus 1.2 +/- 0.5 wires per lesion. The only advantage of the Standard systems was the more common use of 7 French guiding catheters (Magnum: 40%, Standard: 53%, p = 0.09). The Magnum system compares favorably with standard systems for routine PTCA. The robust design of the Magnum wire does not impair ease of placement and safety but saves material and facilitates balloon advancement across the lesion.

Aged↗
PubMed1992

Intracoronary electrocardiogram during coronary angioplasty.

This prospective study examines the data derived from the intracoronary electrocardiogram (ECG) (derived from the coronary guide wire) compared with that from four standard surface leads (I, II, III, and V2) in documenting myocardial ischemia during coronary angioplasty. Intracoronary and surface ECGs were simultaneously recorded in 300 consecutive patients (mean age 59 +/- 10; range 33 to 80 years; 246 males [82%] during coronary angioplasty in 368 lesions (167 left anterior descending [46%], 85 left circumflex [23%], 107 right coronary arteries [29%], and nine bypass grafts [2%]), before balloon inflation, at 1 minute of inflation, and at the end of the procedure. ST segment changes (greater than 0.1 mV) were observed in the intracoronary ECG in 306 lesions (83%) (151 left anterior descending [88%], 75 left circumflex [89%], and 80 right coronary arteries [73%]) versus in 245 lesions (67%) in the surface ECG (126 left anterior descending [73%], 43 left circumflex [47%], and 76 right coronary arteries [70%]; [p less than 0.0001]). The mean ST segment shift was 0.5 +/- 0.4 mV in intracoronary and 0.1 +/- 0.2 mV in standard leads (p less than 0.0001). ST elevation was seen in 97% of cases with intracoronary ECG changes versus in 83% with surface ECG changes. The remainder had ST depression. A total of 48 lesions (13%) did not produce ECG changes and 62 (16%) had silent ischemia. In 75 lesions (21%), ECG changes were seen only in the intracoronary ECG, compared with 14 lesions (4%) with changes only in the surface ECG (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1992

Magnum/Magnarail versus conventional systems for recanalization of chronic total coronary occlusions: a randomized comparison.

The Magnum/Magnarail system consists of "over-the-wire" balloon catheters and a 0.021 inch (0.53 mm) guide wire with a 1 mm olive-shaped tip. To compare it to conventional systems, 100 consecutive unselected patients with chronic total coronary occlusions were randomly assigned to one of two groups. If the balloon could not be placed within 20 minutes of fluoroscopy time with the allocated system, a crossover to the other system was imposed. The Magnum group comprised 50 patients and 52 occlusions, and the conventional group included 50 patients and 51 occlusions. There were no significant differences with regard to the length of the occlusions (Magnum 1.4 +/- 1.3 mm, conventional 1.6 +/- 1.7 mm) or the duration (Magnum 1.4 +/- 1.9 months, conventional 1.4 +/- 1.8 months). The primary success rate before crossover with the Magnum/Magnarail system was 67% versus 45% with conventional systems (p less than 0.05). The Magnum/Magnarail system as a second tool after crossover was successful in 11 of 28 patients (39%) versus 2 of 16 patient (12%) in whom success was achieved with a conventional system as a second tool (p less than 0.05). An increase in the creatine kinase level (more than twice normal) was seen in one patient (2%) in the Magnum/Magnarail group and none in the conventional group. Q wave infarctions were not seen. There was one in-hospital death (2%) in the conventional group. There were no significant differences with regard to the number of guiding and balloon catheters or fluoroscopy time. The Magnum/Magnarail system proved superior to conventional systems for balloon recanalization of chronic total coronary occlusions in terms of higher success rates.

Aged↗
PubMed1992

A software tool to assist placement of multiple parallel brachytherapy sources using the Brown-Roberts-Wells stereotactic system.

The authors present a simple software written in Turbo Pascal which allows placement of multiple parallel sources for interstitial brachytherapy using the Brown-Roberts-Wells CT stereotactic system. The user can choose any direction in space, independently from the CT plane, and any number of linear sources arranged on one or more hypothetical cylinders of variable radius. The sources can be rotated on the cylinder in order to avoid critical structures. This small program runs on any IBM compatible computer.

Brachytherapy↗
PubMed1992

Extraocular sebaceous carcinoma.

A 79-year-old man with no history of previous irradiation presented with a large ulcerated tumour of the cheek. The histological features favoured a true sebaceous carcinoma. Neither squamous nor basal differentiation were seen. Sudan stainings were positive. Tumour cells expressed suprabasal keratins and were negative for carcinoembryonic antigen, vimentin and S 100 protein. Extraocular sebaceous carcinomas occurring without previous irradiation are rare tumours which behave aggressively. Treatment regimens are discussed.

Adenocarcinoma↗
PubMed1991

Coronary balloon angioplasty through diagnostic 6 French catheters.

We investigated the use of ultralow profile balloon catheters (Scimed ACE, USCI Probe, Cordis, Orion) for coronary angioplasty through 6 French diagnostic catheters (Schneider, Cordis). Contrast injection was assisted with a Hercules pump (Cordis) in all cases. During 21 procedures, angioplasty of 27 lesions in 20 selected patients was attempted (1.3 lesion/procedure). Twelve lesions were in the right, 10 in the left anterior descending, and 5 in the left circumflex coronary artery. Balloon size varied between 2.5 and 3.5 mm. Twenty lesions could be successfully dilated (74%) through the 6 French catheter and 7 lesions required an exchange to a 7 French angioplasty guiding catheter. For 5 cases, another balloon was also necessary to complete the procedure. The final overall success rate was 100% per patient and per lesion and there were no major complications. Despite the small internal catheter lumen (1.22 mm) coronary visualization was adequate, and mechanical support was good. Failures of 6 French catheters were attributed to insufficient torque control and excessive friction when the balloon crossed the tapered end of the diagnostic catheter. Coronary angioplasty through a diagnostic 6 French catheter is feasible and may represent a reasonable alternative for simple cases that are done during the same session as the diagnostic angiography. Once available, 6 French high flow angioplasty guiding catheters without a tapered tip should improve success while retaining the advantage of a small femoral puncture site.

Angiography↗
PubMed1990

Long-term results of successful and failed angioplasty for chronic total coronary arterial occlusion.

The results over a mean period of 2 years of successful percutaneous transluminal coronary angioplasty (PTCA) in 100 consecutive patients with chronic total coronary occlusion were compared with those in 100 consecutive patients whose PTCA was unsuccessful. The groups were comparable in terms of gender, age and arteries attempted. A control angiography in the group with successful PTCA was performed in 62 patients and showed a restenosis in 28 (45%). Repeat PTCA was performed in 21 versus 1 patient with failed PTCA (p less than 0.0001). At follow-up, in the group with successful PTCA, there were 57 symptom-free patients versus 26 patients in the group with failed PTCA (p less than 0.0001). Coronary artery bypass surgery was performed in 7 versus 37 patients (p less than 0.0001), and there were 5 versus 3 deaths (difference not significant), respectively. In the group with successful PTCA, 27 of 82 patients (33%) had positive stress test results, compared with 49 of 85 patients (58%) in the group with unsuccessful PTCA (p less than 0.001). The double product (beats/min x mm Hg/100) in patients with successful PTCA improved from 247 +/- 57 before PTCA to 277 +/- 61 (p less than 0.001) at follow-up, whereas it did not significantly change in patients with failed PTCA. The work load (W) in patients with successful PTCA improved from 95 +/- 34 before PTCA to 124 +/- 40 at follow-up (p less than 0.001). In patients with failed PTCA, work load improved less significantly, from 98 +/- 37 before PTCA to 108 +/- 34 at follow-up (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1990

Configuration of a robot dedicated to stereotactic surgery.

The design of a robot for functional stereotactic surgery which is under construction in our laboratory is described. The main features include operation inside the computed tomographic (CT) scanner, the possibility of intraoperative CT scanning and complete handling of the stereotactic probes by the robot.

Brain Diseases↗