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Biomedical subjects

G Besson

Publications and source records attributed to G Besson.

At least 19 recordsLinked to original sources
PubMed1997

Role of CCR5 in infection of primary macrophages and lymphocytes by macrophage-tropic strains of human immunodeficiency virus: resistance to patient-derived and prototype isolates resulting from the delta ccr5 mutation.

The alpha-chemokine receptor fusin (CXCR-4) and beta-chemokine receptor CCR5 serve as entry cofactors for T-cell (T)-tropic and macrophage (M)-tropic human immunodeficiency virus type 1 (HIV-1) strains, respectively, when expressed with CD4 in otherwise nonpermissive cells. Some M-tropic and dual-tropic strains can also utilize other beta-chemokine receptors, such as CCR2b and CCR3. A mutation of CCR5 (delta ccr5) was recently found to be common in certain populations and appears to confer protection against HIV-1 in vivo. Here, we show that this mutation results in a protein that is expressed intracellularly but not on the cell surface. Primary CD4 T cells from delta ccr5 homozygous individuals were highly resistant to infection with prototype M-tropic HIV-1 strains, including an isolate (YU-2) that uses CCR5 and CCR3, but were permissive for both a T-tropic strain (3B) and a dual-tropic variant (89.6) that uses CXCR-4, CCR5, CCR3, or CCR2b. These cells were also resistant to M-tropic patient isolates but were readily infected by T-tropic patient isolates. Primary macrophages from delta ccr5 homozygous individuals were also resistant to infection with M-tropic strains, including YU-2, but the dual-tropic strain 89.6 was able to replicate in them even though macrophages are highly resistant to CXCR-4-dependent T-tropic isolates. These data show that CCR5 is the essential cofactor for infection of both primary macrophages and T lymphocytes by most M-tropic strains of HIV-1. They also suggest that CCR3 does not function for HIV-1 entry in primary lymphocytes or macrophages, but that a molecule(s) other than CCR5 can support entry into macrophages by certain virus isolates. These studies further define the cellular basis for the resistance to HIV-1 infection of individuals lacking functional CCR5.

CD4 Antigens↗
PubMed1997

Successful surgical treatment of intraorbital arteriovenous malformations: case report.

OBJECTIVE AND IMPORTANCE: Cases of intraorbital arteriovenous malformations are rare, and their management presents a challenge for multidisciplinary teams. CLINICAL PRESENTATION: A 39-year-old woman developed a pulsating exophathalmos, visual loss, and ocular pain within 1 month, revealing the presence of intraorbital arteriovenous malformations. She underwent only surgical treatment. INTERVENTION: A fronto-orbital approach with removal of the orbital rim was performed. A CO2 laser facilitated all the surgical steps. CONCLUSION: Full recovery of vision and correction of the proptosis have been achieved, and postoperative magnetic resonance imaging and angiography confirmed the total removal of the malformations. The literature is reviewed regarding the management of such lesions. Surgery remains the treatment of choice. The role of embolization is discussed.

Adult↗
PubMed1996

The place of decompressive surgery in the treatment of uncontrollable post-traumatic intracranial hypertension in children.

The authors report two cases of post-traumatic uncontrollable intracranial hypertension in children (120 torr in case 1; 90 torr in case 2) who were treated within the first 12 h after trauma by surgery including decompressive craniectomy. The outcome was favourable in both children. Intracranial pressure (ICP) was recorded during the pre-, intra- and postoperative periods and during each specific step of the surgical procedure. Craniectomy alone induced a decrease in ICP of 45% (40 torr) in case 1 and 30% (35 torr) in case 2. Although this method remains controversial, given the lack of controlled trials, it can offer a salvage procedure in children with rapidly worsening intracranial hypertension, allowing survival without disabling neurological sequelae.

Brain Concussion↗
PubMed1996

The stroke syndrome of cortical vein thrombosis.

Cortical vein thrombosis without sinus involvement is rarely diagnosed, although it may commonly be overlooked. We report four cases of cerebral venous thrombosis limited to the cortical veins. The diagnosis was made on surgical intervention in one patient and by angiography in three patients. Together with a survey of the published cases, the clinical and neuroimaging patterns of our patients allow delineation of several features suggestive of cortical venous stroke. Focal or generalized seizures followed by hemiparesis, aphasia, hemianopia, or other focal neurologic dysfunction in the absence of signs of increased intracranial pressure should suggest this possibility. Neuroimaging (CT, MRI) shows an ischemic lesion that does not follow the boundary of arterial territories and often has a hemorrhagic component, without signs of venous sinus thrombosis. Conventional angiography demonstrates no arterial occlusion but may show cortical vein thrombosis corresponding to the infarct, although these may also be nonspecific findings. The role of MR angiography, which is well-established in sinus thrombosis, remains to be assessed in patients with brain ischemia due to isolated cortical vein occlusion.

Adult↗
PubMed1995

Vertebrobasilar infarcts in patients with dolichoectatic basilar artery.

We reported 18 patients who had stroke in the posterior circulation with dolichoectatic basilar artery. TIAs preceded posterior circulation infarct in 5 patients. Strokes involved medulla oblongata (3), pons (4), cerebellum (4), mesencephalon (4), thalamus or occipital lobe (3). Dolichoectatic basilar artery also produced hydrocephalus in one patient. The mechanism of stroke may be due to penetrating artery occlusion, basilar artery thrombosis or an embolism from the abnormal basilar artery. Short-term prognosis was poor seeing that 4 patients died within 12 days of stroke.

Adult↗
PubMed1995

Is it clinically possible to distinguish nonhemorrhagic infarct from hemorrhagic stroke?

BACKGROUND AND PURPOSE: Diagnosis of the nonhemorrhagic ischemic type of stroke by analysis of patients' clinical features is considered unreliable because no clinical feature is specific. The diagnosis is so difficult to establish that we cannot hope to use the same method to make a reliable diagnosis in all stroke cases. In this study, we propose a simple scoring system with a positive predictive value of close to 100% to distinguish nonhemorrhagic infarct from hemorrhagic stroke. This scoring is available for all physicians in bedside diagnosis even if this score can be applied to a subgroup of patients. METHODS: Twenty-six clinical variables that might potentially distinguish cerebral hemorrhage from infarction were recorded in patients consecutively admitted to our stroke unit for stroke lasting more than 24 hours with at least unilateral motor weakness affecting face and/or arm and/or leg (internal validity study). Patients previously receiving anticoagulant therapy were excluded. We used CT scan as the gold standard. We used multivariate logistic regression to establish a clinical score from which we derived the classification rule. This rule was validated with data from the next 200 consecutive patients hospitalized in the stroke unit (external validity study). RESULTS: Three hundred sixty-eight patients were enrolled in the internal study. The obtained score was (2 x alcohol consumption) + (1.5 x plantar response) + (3 x headache) + (3 x history of hypertension)--(5 x history of transient neurological deficit)--(2 x peripheral arterial disease)--(1.5 x history of hyperlipidemia)--(2.5 x atrial fibrillation on admission). All patients with a score less than 1 (n = 123) had a nonhemorrhagic infarct (ie, 40% of the 305 patients with a nonhemorrhagic infarct). No threshold was found to diagnose cerebral hemorrhage with a sufficiently high positive predictive value. Among the 200 patients enrolled in the external validity study, 72 patients with a score below 1 had a nonhemorrhagic infarct (ie, 43% of patients with a nonhemorrhagic infarct). CONCLUSIONS: Diagnosis of nonhemorrhagic infarct can be made in 36% (95% confidence interval [CI], 29 to 43) of patients with a high level of accuracy (100% in the external validity study, which gives a 95% CI of 93 to 100). Thus, 43% (95% CI, 36 to 50) of patients with a nonhemorrhagic infarct could receive a bedside diagnosis. The score is simple and can be calculated from information available to all physicians.

Adult↗
PubMed1994

Atherosclerotic disease of the aortic arch and the risk of ischemic stroke.

BACKGROUND: Atherosclerotic disease of the aortic arch has been suspected to be a potential source of cerebral emboli. We conducted a study to quantify the risk of ischemic stroke associated with atherosclerotic disease of the aortic arch. METHODS: Using transesophageal echocardiography, we performed a prospective case-control study of the frequency and thickness of atherosclerotic plaques in the ascending aorta and proximal arch in 250 consecutive patients admitted to the hospital with ischemic stroke and 250 consecutive controls, all over the age of 60 years. RESULTS: Atherosclerotic plaques > or = mm in thickness were found in 14.4 percent of the patients but in only 2 percent of the controls. After adjustment for atherosclerotic risk factors, the odds ratio for ischemic stroke among patients with such plaques was 9.1 (95 percent confidence interval, 3.3 to 25.2; P < 0.001). Among the 78 patients who had brain infarcts with no obvious cause, 28.2 percent had plaques > or = 4 mm in thickness, as compared with 8.1 percent of the 172 patients who had infarcts whose possible or likely causes were known (odds ratio, 4.7; 95 percent confidence interval, 2.2 to 10.1; P < 0.001). Plaques of > or = 4 mm in the aortic arch were not associated with the presence of atrial fibrillation or stenosis of the extracranial internal carotid artery. In contrast, plaques that were 1 to 3.9 mm thick were frequently associated with carotid stenosis of > or = 70 percent. CONCLUSIONS: These results indicate a strong, independent association between atherosclerotic disease of the aortic arch and the risk of ischemic stroke. The association was particularly strong with thick plaques. Atherosclerotic disease of the aortic arch should be regarded as a risk factor for ischemic stroke and as a possible source of cerebral emboli.

Aged↗
PubMed1994

Patent foramen ovale in young stroke patients with mitral valve prolapse.

Because mitral valve prolapse and patent foramen ovale are supposed to promote stroke in young patients, we assessed the frequency of patent foramen ovale in 18 patients younger than 45 years with stroke and mitral valve prolapse diagnosed on echocardiography at the time of stroke, who were admitted to 2 university hospitals. Eleven patients were called back to hospital for contrast transthoracic and/or transesophageal echocardiography, 3 to 7 years after their initial stroke. A patient foramen ovale was found in 9 patients (50%). In 4 re-assessed patients no mitral valve prolapse was found using our present criteria. Six patients with mitral valve prolapse had a patent foramen ovale (43%). Our results suggest that mitral valve prolapse is commonly associated with patent foramen ovale in young stroke patients.

Adolescent↗
PubMed1994

Long-term prognosis of symptomatic lacunar infarcts. A hospital-based study.

BACKGROUND AND PURPOSE: This study concerns the long-term prognosis of lacunar infarcts. METHODS: We report the analysis of our hospital-based series of 178 patients consecutively admitted for a lacunar syndrome due to a lacunar infarct diagnosed with computed tomography and magnetic resonance imaging. Demographic data, medical history, vascular risk factors, and imaging data were recorded for each patient. The follow-up was 35 +/- 22 months. RESULTS: The lacunar syndrome was pure motor hemiparesis in 69 patients (39%), ataxic hemiparesis in 45 patients (25.4%), pure sensory stroke in 15 patients (8.5%), sensorimotor stroke in 14 patients (7.9%), and miscellaneous syndrome in 34 patients (19.2%). The 4-year survival rate was 80 +/- 4% and the 4-year survival rate without recurrent stroke was 85 +/- 3.5%. Using Cox proportional-hazards analysis, the predictors of death were age (P < .02), diabetes mellitus (P < .05), and cigarette smoking (P < .05). We did not find any predictors of recurrence. After 1 year, 74% of the patients had mild or no disability. Using logistic regression analysis, the predictive factors of disability were age more than 70 years (P < .01), diabetes (P < .01), history of stroke or transient ischemic attack (P < .05), and type of lacunar syndrome (P < .01). Imaging data, number of lacunes, and presence of leukoaraiosis were not predictors of outcome. CONCLUSIONS: Our study suggests that with a high survival rate, a low recurrence rate, and a relatively good functional recovery, lacunar infarcts have a relatively favorable prognosis.

Activities of Daily Living↗
PubMed1994

Capsaicin-induced airway obstruction in tracheally perfused guinea pig lungs.

The neurokinin receptors responsible for transducing the airway obstruction resulting from capsaicin infusion were defined in the tracheally perfused guinea pig lung. In this lung preparation, buffer is perfused via the trachea and allowed to exit the lung through numerous small holes in the pleural surface; airway obstruction is monitored as the backpressure (Pao) generated at a constant perfusion flow rate. Infusion of the specific NK1 receptor agonist, Sar-9 Met02(11) substance P, resulted in an increase in Pao; this effect was prevented by the NK1 receptor antagonist CP 99,994 but not by the NK2 receptor antagonist SR 48,968. Infusion of the specific NK2 receptor agonist Nle10-neurokinin A 4-10 resulted in an increase in Pao; this effect was prevented by the NK2 receptor antagonist SR 48,968 but not by the NK1 receptor antagonist CP 99,994. In the absence of NK receptor antagonists, infusion of capsaicin resulted in a significant increase in Pao, 31 +/- 4 cm H2O. In the presence of the NK1 receptor antagonist, the capsaicin response was not diminished, but in the presence of the NK2 receptor antagonist, the Pao response diminished to only 10 +/- 2 cm H2O, p < 0.001. These data indicate that when capsaicin is presented to the epithelial surface of the lung the resulting airway obstruction is mediated predominantly by NK2 receptor stimulation.

Animals↗
PubMed1994

[Treatment of chronic lumbago and radicular pain by spinal cord stimulation. Long-term results].

Seventy-seven patients with chronic, refractory, low back and radicular pain underwent implantation of a spinal cord stimulator between 1984 and 1992. Most patients had failed back surgery syndrome. In every case, an epidural quadripolar "Resume" electrode was implanted surgically. Results were evaluated after three months then after six to 98 months (mean follow-up 42 months). Long-term efficacy was good in 63.6% of cases, fair in 22%, and poor in 6.5%; treatment failure occurred in 7.9% of cases. Adverse events included one case of meningitis, two cases of local infection, and one case each of cerebrospinal fluid fistula and necrosis of the skin overlying the stimulator. The main causes of treatment failure were complications, inappropriate patient selection, and the escape phenomenon. The results of this study demonstrate that spinal cord stimulation is effective for the treatment of chronic low back and radicular pain in carefully selected patients; scrupulous application of restrictive selection criteria is essential to the success of the method.

Adult↗
PubMed1993

[Juxta- or trans-condylar lateral extension of the posterior suboccipital approach. Anatomical study, surgical aspects].

In order to improve the surgical approach to tumors and aneurysms of the anterior or antero-lateral aspect of the foramen magnum, some authors have proposed a lateral extension of the posterior sub-occipital approach to the occipital condyle including in some cases its partial or complete resection. The evaluation of this close medio-condylar or trans-condylar suboccipital approach has been performed on eight coloured-latex injected specimens in the conditions of a microsurgical operation. The extra- and intradural steps have been studied so as to define the optimal position of the patient's head and the surgeon and to precise the accessible anatomical structures: Vertebral artery (and its control), Cranial nerves IX, X, XI & XII, Posterior-inferior cerebellar artery and collaterals, Vertebro-basilar junction, antero-lateral aspect of the brain stem and spinal cord. Depending on the extent of the condylar resection, the lateral extension of the posterior sub-occipital approach may be defined as minimal, moderate or large. Based on anatomical and surgical constations it appears that a complete resection of the occipital condyle (resulting in occipito-cervical instability) should be reserved for those very extensive lesions. Yet a partial drilling of the condyle provides a better angle of approach, minimises the hazards of retraction of nervous structures and enables the surgeon to take the best advantage of the dissection and control of the vertebral artery.

Female↗
PubMed1993

[Jugular foramen syndrome caused by herpes zoster].

Multiple cranial nerve palsies frequently occur in patients with cephalic zoster. Nevertheless, to our knowledge, involvement of the glossopharyngeal (IXth), vagus (Xth) and accessory (XIth) nerves has not yet been reported. We report a case of jugular foramen syndrome with palatolaryngeal herpetic eruption, aseptic meningitis and a high level of serum antibody to varicella-zoster virus.

Accessory Nerve↗