Biomedical subjects

Pascal Branchereau

Publications and source records attributed to Pascal Branchereau.

13 recordsLinked to original sources

PubMed2006

Expression of the glycinergic system during the course of embryonic development in the mouse spinal cord and its co-localization with GABA immunoreactivity.

To understand better the role of glycine and gamma-aminobutyric acid (GABA) in the mouse spinal cord during development, we previously described the ontogeny of GABA. Now, we present the ontogeny of glycine-immunoreactive (Gly-ir) somata and fibers, at brachial and lumbar levels, from embryonic day 11.5 (E11.5) to postnatal day 0 (P0). Spinal Gly-ir somata appeared at E12.5 in the ventral horn, with a higher density at the brachial level. They were intermingled with numerous Gly-ir fibers reaching the border of the marginal zone. By E13.5, at the brachial level, the number of Gly-ir perikarya sharply increased throughout the whole ventral horn, whereas the density of fibers declined in the marginal zone. In the dorsal horn, the first Gly-ir somata were then detected. From E13.5 to E16.5, at the brachial level, the density of Gly-ir cells remained stable in the ventral horn, and after E16.5 it decreased to reach a plateau. In the dorsal horn, the density of Gly-ir cells increased, and after E16.5 it remained stable. At the lumbar level, maximum expression was reached at E16.5 in both the ventral and dorsal horn. Finally, the co-localization of glycine and GABA was analyzed, in the ventral motor area, at E13.5, E15.5, and E17.5. The results showed that, regardless of developmental stage studied, one-third of the stained somata co-expressed GABA and glycine. Our data show that the glycinergic system matures 1 day later than the GABAergic system and follows a parallel spatiotemporal evolution, leading to a larger population of glycine cells in the ventral horn.

Animals↗

PubMed2005

Ontogenic changes of the spinal GABAergic cell population are controlled by the serotonin (5-HT) system: implication of 5-HT1 receptor family.

During the development of the nervous system, the acquisition of the GABA neurotransmitter phenotype is crucial for neural networks operation. Although both intrinsic and extrinsic signals such as transcription factors and growth factors have been demonstrated to govern the acquisition of GABA, few data are available concerning the effects of modulatory transmitters expressed by axons that progressively invade emerging neuronal networks. Among such transmitters, serotonin (5-HT) is a good candidate because serotonergic axons innervate the entire CNS at very early stages of development. We have shown previously that descending 5-HT slows the maturation of inhibitory synaptic transmission in the embryonic mouse spinal cord. We now report that 5-HT also regulates the spatiotemporal changes of the GABAergic neuronal population in the mouse spinal cord. Using a quantitative confocal study performed on acute and cultured spinal cords, we find that the GABAergic population matures according to a similar rostrocaudal temporal gradient both in utero and in organotypic culture. Moreover, we show that 5-HT delays the appearance of the spinal GABAergic system. Indeed, in the absence of 5-HT descending inputs or exogenous 5-HT, the GABAergic population matures earlier. In the presence of exogenous 5-HT, the GABA population matures later. Finally, using a pharmacological approach, we show that 5-HT exerts its action via the 5-HT1 receptor family. Together, our data suggest that, during the course of the embryonic development, 5-HT descending inputs delay the maturation of lumbar spinal motor networks relative to brachial networks.

Animals↗

PubMed2005

Acute carotid artery thrombosis: description of 12 surgically treated cases.

The morbidity and mortality of stroke secondary to acute internal carotid artery thrombosis range from 40 to 69% and from 15 to 55%, respectively, after purely medical treatment. This report describes a series of 12 patients who underwent urgent surgical treatment for primary acute carotid artery thrombosis between January 1999 and December 2002. Upon admission, all patients had severe neurologic deficits contralateral to carotid artery thrombosis. One patient experienced ongoing changes in the level of consciousness. The interval between the onset of symptoms and admission was less than 6 hr in all cases. Initial work-up in all patients included a brain computed tomographic scan with contrast injection and carotid duplex scan. The operative procedure consisted of carotid thomboemdarterectomy after shunt placement with prosthetic patch closure. Intraoperative angiography was performed in all cases. Following treatment, we observed deterioration of neurologic status leading to death in one case; improvement with partial regression of initial neurologic deficit in two cases, including one patient who died from causes unrelated to carotid artery disease; and full neurologic recovery in nine cases. The delay to revascularization was longer than 6 hr in both patients who died. These data support surgical intervention for carotid artery thrombosis in selected patients without major disturbances of consciousness or hemorrhagic infarction, provided that the delay to revascularization is less than 6 hr.

Aged↗

PubMed2004

Ontogenic changes of the GABAergic system in the embryonic mouse spinal cord.

Numerous studies have demonstrated an excitatory action of GABA early in development, which is likely to play a neurotrophic role. In order to better understand the role of GABA in the mouse spinal cord, we followed the evolution of GABAergic neurons over the course of development. We investigated, in the present study, the ontogeny of GABA immunoreactive (GABA-ir) cell bodies and fibers in the embryonic mouse spinal cord at brachial and lumbar levels. GABA-ir somata were first detected at embryonic day 11.5 (E11.5) exclusively at brachial level in the marginal zone. By E13.5, the number of GABAergic neurons sharply increased throughout the extent of the ventral horn both at brachial and lumbar level. Stained perikarya first appeared in the future dorsal horn at E15.5 and progressively invaded this area while they decreased in number in the presumed ventral gray matter. At E12.5, E13.5 and E15.5, we checked the possibility that ventral GABA-ir cells could belong to the motoneuronal population. Using a GABA/Islet-1/2 double labeling, we did not detect any double-stained neurons indicating that spinal motoneurons do not synthesize GABA during the course of development. GABA-ir fibers also appeared at the E11.5 stage in the presumptive lateral white matter at brachial level. At E12.5 and E13.5, GABA-ir fibers progressively invaded the ventral marginal zone and by E15.5 reached the dorsal marginal zone. At E17.5 and postnatal day 0 (P0), the number of GABA-ir fibers declined in the white matter. Finally, by P0, GABA immunoreactivity that delineated somata was mainly restricted to the dorsal gray matter and declined in intensity and extent. The ventral gray matter exhibited very few GABA-ir cell bodies at this neonatal stage of development. The significance of the migration of somatic GABA immunoreactivity from ventral to the dorsal gray matter is discussed.

Animals↗

PubMed2004

Multiple spontaneous rhythmic activity patterns generated by the embryonic mouse spinal cord occur within a specific developmental time window.

Spontaneous rhythmic activity is a ubiquitous phenomenon in developing neural networks and is assumed to play an important role in the elaboration of mature circuitry. Here we describe the day-by-day evolution of spontaneous activity in the embryonic mouse spinal cord and show that, at a specific developmental stage, 2 distinct rhythms coexist. On embryonic days E12.5 and E13.5, we observed a single type of regularly recurring short spike-episodes synchronized across cervical, thoracic, and lumbar levels. By E14.5, in addition to this motor rhythm, another type of spontaneous synchronous activity appeared, characterized by much longer lasting episodes separated by longer time intervals. On E15.5, these long episodes disappeared. Short episodes were less numerous and more irregular except at the cervical level where a rhythm was occasionally observed. By E16.5, this cervical rhythm became more robust, whereas the lumbar level fell almost silent. Surprisingly, at E17.5, spontaneous activity resumed at caudal levels, now characterized by numerous erratic short episodes. A striking ontogenetic feature of spontaneous activity was the occurrence of long episodes only at E14.5. Although concomitant at all levels of the spinal cord, long episodes displayed different patterns along the spinal cord, with tonic firing at the thoracic level and rhythmic discharge with occasional sequences of left/right alternation at the lumbar level. Thus at E14.5, the originally synchronized network has started to segregate into more specialized subnetworks. In conclusion, this work suggests that ongoing spontaneous rhythms do not follow a smooth evolution during maturation, but rather undergo profound changes at very specific stages.

Animals↗

PubMed2003

Ruptured aneurysm of the infrarenal abdominal aorta: impact of age and postoperative complications on mortality.

Between 1985 and 2000, a total of 871 patients underwent surgical treatment for infrarenal abdominal aortic aneurysm (AAA), including 98 (11.2%) presenting with ruptured abdominal aortic aneurysms (RAAA). An optimized operative protocol was used to treat 77 RAAA starting in January 1989. The main features of the optimized protocol are routine use of intraoperative autotransfusion, revascularization by aortoaortic bypass, absence of systemic heparinization, and use of a collagen-impregnated prosthesis. Intraoperative mortality (IOM) was 3.8%. Postoperative mortality at 1 month (POM1) was 25.9% and postoperative mortality at 3 months (POM3) was 33.7%. Heart failure (p <0.001), hemodynamic shock (p <0.001), and hemorrhage (p = 0.04) were the only complications correlated with POM1. Pneumonia (p = 0.01) and sepsis (p = 0.01) were the only complications correlated with POM3. Isolated acute renal insufficiency was not a significant risk factor for postoperative mortality. Using a cutoff of 75 years, there was a significant age-related difference (p = 0.025) for POM1 but not for IOM and POM3. The findings of this study show that optimizing the operative protocol decreases mortality related to RAAA. The main predictor of POM1 was hemodynamic status while the main predictor of POM3 was infection. Isolated acute renal insufficiency was not a risk factor for mortality. Age should not be considered a contraindication for operative treatment.

Age Factors↗

PubMed2003

Endovascular repair for acute traumatic rupture of the thoracic aorta.

BACKGROUND: We report endovascular treatment of acute traumatic rupture of the thoracic aorta as a potential alternative to open surgery for high-risk patients. METHODS: Between January 2001 and July 2002, 9 patients with acute traumatic rupture of the thoracic aorta were treated with a stent-graft. In all cases the endovascular management was selected because of age, associated polytrauma, or comorbidities. Preoperative workup included chest computed tomography scan, transoesophageal echography, and angiography. The devices used were the Excluder and the Talent stent-grafts. RESULTS: Eight patients underwent immediate repair and 1 patient was treated within 5 days of the accident because of delayed diagnosis of aortic rupture after surgical management of spleen rupture. The stent-graft was successfully expanded in all patients through the common femoral artery (n = 7) or the common iliac artery (n = 2). There was no perioperative death, renal failure, or neurologic complication (paraplegia or stroke). In 1 patient the computed tomography scan at 7 days postoperatively showed proximal endoleak requiring placement of a second stent-graft. Follow-up ranged from 4 to 20 months. All spiral computed tomography scans performed during follow-up revealed no evidence of endoleak, migration, or alteration of the stent-graft. CONCLUSIONS: Endovascular repair in the acute phase of traumatic rupture of the thoracic aorta is technically feasible and safe, and may represent an alternative to open surgery for high-risk patients.

Acute Disease↗

PubMed2002

Video-assisted thoracoscopic sympathectomy for palmar hyperhidrosis: results in 102 cases.

The purpose of this retrospective study was to evaluate the immediate and long-term outcome of video-assisted thoracoscopic sympathectomy for idiopathic palmar hyperhidrosis. Between January 1996 and December 2000, a total of 67 patients underwent 102 sympathectomy procedures with excision of the sympathetic chain between the second and fourth sympathetic ganglion. The mean duration of hospitalization was 1.7 +/- 0.6 days. Five patients were lost to follow-up. Mean duration of follow-up for the 96 sympathectomy procedures in the remaining 62 patients was 38 +/- 6.3 months. Patient outcome showed that video-assisted thoracoscopic sympathectomy is the treatment of choice for idiopathic palmar hyperhidrosis. Long-term patient satisfaction is excellent.

Adolescent↗

PubMed2002

Ontogeny of descending serotonergic innervation and evidence for intraspinal 5-HT neurons in the mouse spinal cord.

Neuronal networks in the mouse spinal cord express serotonin (5-HT)-induced rhythmic motor activity at early developmental stages (embryonic day (E) 12.5). Later in development, by post-natal day (P) 10, the 5-HT-evoked rhythmic motor activity matures and acquires an adult locomotor-like pattern. With the view to establishing a relationship between the ontogeny of locomotor networks and the maturation of spinal 5-HT systems, we have traced 5-HT immunoreactivity in the mouse spinal cord from E12.5 to PN10. By E12.5, descending 5-HT immunoreactive (5-HT-ir) fibers that likely originate from raphe nuclei were detected in the ventral and lateral funiculi, at anterior cervical spinal levels, but not at more caudal levels. Descending 5-HT-ir axons reached thoracic levels at E14.5 and lumbar levels at E16.5. Some 5-HT-ir fibers could be detected in the ventral and intermediate gray matter by E16.5, whereas the dorsal gray matter was not invaded before PN0. At PN10, a dense serotonergic innervation was restricted to the gray matter with a high concentration of 5-HT-ir fibers in three areas: dorsal horn, ventral horn (where motoneurons are located) and intermediate area. Surprisingly, from E16.5 to PN10, 5-HT-ir intraspinal neurons were found, exclusively at sacral levels. Their somata lay in the gray matter around the central canal and preferentially in the ventro-median part of the ventral horn. The functional significance of these sacral 5-HT-ir neurons is discussed.

Animals↗

PubMed2002

Descending 5-hydroxytryptamine raphe inputs repress the expression of serotonergic neurons and slow the maturation of inhibitory systems in mouse embryonic spinal cord.

Spontaneous synchronous rhythmic activities are a common feature of immature neuronal networks. Although the mechanisms underlying such activities have been studied extensively, whether they might be controlled by modulatory information remains questionable. Here, we investigated the role of descending serotonergic (5-HT) inputs from the medulla to the spinal cord in the maturation of rhythmic activity. We found that in spinal cords maintained, as a whole, in organotypic culture without the medulla, the maturation of spontaneous activity is similar to that found in spinal cords developed in utero. Interestingly, in organotypic cultures without the medulla (i.e., devoid of descending inputs), numerous intraspinal neurons expressed 5-HT, unlike in spinal cords cultivated in the presence of the medulla or matured in utero. We demonstrated that this 5-HT expression was specifically dependent on the absence of 5-HT fibers and was repressed by 5-HT itself via activation of 5-HT(1A) receptors. Finally, to verify whether the expression of 5-HT intraspinal neurons could compensate for the lack of descending 5-HT fibers and play a role in the development of spontaneous activity, we blocked the 5-HT synthesis using p-chlorophenylalanine methyl ester in cultures devoid of the medulla. Surprisingly, we found that this pharmacological treatment did not prevent the development of spontaneous activity but accelerated the maturation of intraspinal inhibition at the studied stages. Together, our data indicate that descending 5-HT raphe inputs (1) repress the expression of spinal serotonergic neurons and (2) slow the maturation of inhibitory systems in mouse spinal cord.

Action Potentials↗

PubMed2002

Outcome of common iliac arteries after aortoaortic graft placement during elective repair of infrarenal abdominal aortic aneurysms.

PURPOSE: The purpose of this study was determination of the expansion rates relative to the size of the common iliac artery (CIA) after elective placement of a straight aortic tube graft for an infrarenal abdominal aortic aneurysm (AAA). METHODS: Between January 1993 and December 1997, 74 men (mean age, 69 years) with AAA underwent surgical repair with a straight tube graft. All patients underwent preoperative and postoperative computed tomography (CT) scans. The mean follow-up period was 68.3 months. The preoperative CT scan revealed a dilatation of at least one of the two CIAs in 32 patients (43.2%; group A). Within this group, the CIA was ectatic (12 mm < diameter < 18 mm) in 13 patients (subgroup A1) and aneurysmal (diameter >/=18 mm) in 19 patients (subgroup A2). The diameters of both CIAs were normal (diameter </=12 mm) in the other 42 patients (56.8%; group B). RESULTS: Two patients (2.7%) in group A2 needed reoperation because of expansion of the diameter of the CIA; the preoperative diameter of the CIA in both patients was 30 mm. The diameters of the CIA aneurysms in the 17 other patients in subgroup A2 were smaller than 30 mm on the preoperative CT scan. After aortic surgery, the sizes of these aneurysms remained stable the first 5 years and reached a diameter of 30 mm on the CT scans obtained 7 to 8 years after surgery. Overall, 10 of the 74 patients (13.5%) had a CIA aneurysm develop that was smaller than 30 mm in diameter (mean diameter, 19.2 mm) 7 to 8 years after aortic surgery. The presence of a celiac aorta dilatation greater than or equal to 25 mm was the only statistically significant factor predictive of postoperative expansion of a CIA dilatation (P =.03). CONCLUSION: Straight aortoaortic tube grafts are indicated for CIAs with diameters smaller than 18 mm. Aorta biiliac bifurcated grafts are justified when the CIA diameter is between 18 and 30 mm, when the patient's life expectancy is longer than 8 years, or when the diameter of the celiac aorta is greater than or equal to 25 mm. A CIA aneurysm greater than or equal to 30 mm should be repaired during the same operative session as the AAA with placement of an aorta biiliac bifurcated graft.

Aged↗

PubMed2002

Carotid artery stenting for stenosis following revascularization or cervical irradiation.

PURPOSE: To assess the safety and efficacy of carotid artery stenting (CAS) for stenosis following revascularization or cervical irradiation. METHODS: Twenty-two CAS procedures performed on 21 patients (20 men; mean age 69.3 years, range 58-87) from June 1997 to June 2000 were retrospectively reviewed. There were 5 radiation-induced carotid stenoses in 4 patients and 17 postsurgical restenoses. The mean interval between carotid revascularization and CAS was 48.1 months (range 6-264), while the elapsed time from irradiation to CAS was always >8 years (range 8-28). Seven patients screened during this period were excluded from CAS because of a duplex-defined >50% hypoechoic lesion and/or angiographic documentation of an irregular ulcerated stenosis. RESULTS: Four Palmaz and 16 Wallstents were successfully deployed in 20 arteries; 1 access failure prompted conversion to surgery and a stent delivery failure resulted in 1 patient receiving balloon dilation only (technical success 91%). No complications were encountered in the periprocedural period, and no neurological events were observed during a mean follow-up of 16.6 months (range 3-36). One patient died at 20 months from an unrelated cause. One (4.8%) restenosis was detected after 1 year in the patient who did not receive a stent. CONCLUSIONS: CAS is a safe alternative to conventional surgery in patients with carotid artery stenosis following surgical revascularization or cervical irradiation provided preoperative testing excludes stenoses at risk for embolism.

Aged↗

PubMed2002

Endovascular repair for acute rupture of the descending thoracic aorta.

PURPOSE: To report the endovascular treatment of acute descending thoracic aortic rupture as an alternative to open surgery in high-risk patients. METHODS: Between November 1999 and April 2001, 10 patients (7 men; median age 75 years) underwent endovascular stent-grafting of the descending thoracic aorta for acute rupture from an aneurysm (n=7) or blunt trauma (n=3). All patients were evaluated as high operative risk. The aortic rupture was associated with isolated mediastinal hematomas (n=7), left hemothorax (n=2), or aortobronchial fistula (n=1). The Excluder Thoracic Endoprosthesis was used predominantly. RESULTS: The mean interval to the endovascular repair was 45.3+/-28.4 hours. All stent-grafts were successfully deployed. Two patients required common iliac artery access, and 2 needed covered stents for iatrogenic iliac artery rupture. There was 1 postoperative death (myocardial infarction) and no renal failure, neurological complications, embolization, stent-graft migration, or perigraft leak. One patient died 4 months later from an unrelated cause. At a mean follow-up of 7.9+/-5.1 months, all aneurysms and rupture sites were excluded with no evidence of endoleak or hematoma. CONCLUSIONS: Endoluminal treatment is a feasible technique for the management of acute rupture of the descending thoracic aorta. Long-term studies are required to assess the effectiveness and durability of this technique in comparison to open repair.

Acute Disease↗