Biomedical subjects

J R Vignes

Publications and source records attributed to J R Vignes.

6 recordsLinked to original sources

PubMed2006

In vitro efficacy of three lazaroids in a model of acute chemical neuronal hypoxia.

Free radicals are highly reactive chemicals containing an unpaired electron and are normally produced by the cellular metabolism. But the excessive production of free radicals by oxidative stress is engaged in a large variety of diseases. The goal of this work was to determine the neuroprotective effect of free radical scavengers in an acute in vitro model of neuronal hypoxia. Primary cultures of cortical neurons of rats were exposed to 0.5 mM sodium cyanide for 6 h. Neuron death was evaluated with a lactate dehydrogenase assay. This mortality was up to 66.5% in cultures exposed to 0.5 mM sodium cyanide compared to non-exposed control cultures. Three lazaroids (U-74500A, U-74389G, U-83836E), were added to cultures, at different concentrations (10(-7)-10(-5) M), simultaneously with cyanide, during 6h. These agents caused a reduction in neuronal death, compared to exposed cultures. Efficacy varied with lazaroid compounds and U-74500A decreased neuronal death to 37-23.5%, U-74389G to 37-32%, and U-83836E to 42-33%. These results suggest a partial neuroprotective effect of free radical scavengers since lipid peroxidation is a key cellular event in neuronal injury, and its inhibition with lazaroids could help to reduce brain ischaemic lesions.

Animals↗

PubMed2005

Sacral neuromodulation in lower urinary tract dysfunction.

Vesico-urethral dysfunction is a major problem in daily medical practice due to its psychological disturbances, its social costs and its high impact on quality of life. Recently, sacral neuromodulation, namely the electrical stimulation of the sacral nerves, appears to have become an alternative for radical bladder surgery particularly in cases of idiopathic bladder overactivity. The mechanism of action is only partially understood but it seems to involve a modulation in the spinal cord due to stimulation of inhibitory interneurons. Temporary sacral nerve stimulation is the first step. It comprises the temporary application of neuromodulation as a diagnostic test to determine the best location for the implant and to control the integrity of the sacral root. If test stimulation is successful, a permanent device is implanted. This procedure is safe in experienced hands. So-called idiopathic bladder overactivity still the major indication for this technique. Patients not likely to benefit from the procedure were those with complete or almost complete spinal lesions, but incomplete spinal lesions seemed to be a potential indication. This technique is now also indicated in the case of idiopathic chronic retention and chronic pelvic pain syndrome. When selection is performed, more than three-quarters of the patients showed a clinically significant response with 50% or more reduction in the frequency of incontinent episodes, but the results vary according to the author's mode of evaluation. From the economic point of view, the initial investment in the device is amortized in the mid-term by savings related to lower urinary tract dysfunction. Finally, this technique requires an attentive follow-up and adjustments to the electric parameters so as to optimize the equilibrium between the neurological systems.

Afferent Pathways↗

PubMed2003

[Spectral analysis of the ECG R-R interval permits early detection of vagal responses to neurosurgical stimuli].

OBJECTIVE: To assess the efficacy of ECG spectral analysis, compared with heart rate (HR) monitoring in the detection of vagal response to surgical stimuli. METHODS: Twenty Asa II-III patients (age: 65 +/- 13 years) scheduled for surgery of cerebellopontine angle or implantation of sacral root stimulator were examined. Target controlled infusion of propofol (2-4 microg x ml(-1)) and remifentanil (4 ng x ml(-1)) was guided by the bispectral index (Bis). Arterial pressure via a radial catheter, pulse oximetry and end tidal CO2 were continuously monitored. Spectral analysis was achieved by connecting a computer to the cardiorespiratory monitor. Online power spectrum densities were calculated from the ECG R-R interval by software based on the fast Fourier transform (LabView, National Instruments, USA). Low frequency (LF: 0.04-0.15Hz) and high frequency (HF: 0.15-0.4Hz) were associated with sympathetic and parasympathetic activities respectively. We defined vagal reaction as a decrease in FC or an increase in HF >10% of the prestimuli value. HF and FC were compared according to the detection delay (by a Student t test with p < 0.05 considered significant) and a concordance test with a kappa coefficient (kappa): -1 = total discordance to 1 = total concordance. RESULTS: Twelve vagal reactions (observed in 8 patients) were detected within 5.5 +/- 1.3 s (HF) and 12.4 +/- 1.6 (FC); p < 0.001. Concordance between the 2 parameters was 95% (kappa =0.9). CONCLUSION: The ECG spectral analysis is a non-invasive technique, which permits the detection of intra-operative vagal reactions earlier than conventional monitoring of HR.

Aged↗

PubMed2001

Dorsal rhizotomy with anterior sacral root stimulation for neurogenic bladder.

A spinal cord lesion above the sacral micturition center results in a loss of voluntary control and development of bladder sphincter dysynergia with hyperreflexia of the detrusor and spasticity of the sphincter. Sacral rhizotomy and implantation of an anterior sacral root stimulator appears as an effective method for the treatment not only of voiding dysfunction but also of defecation and sexual disturbance. The surgical technique is described as are the clinical and electrophysiological controls. The results of our series of operated patients with intradural implantation and sacral deaffentation show a constant improvement. 90% have satisfactory continence and no longer require an incontinence appliance. Bladder capacity and compliance have increased to 120% and urethral closure pressure has decreased. 80% have complete voiding or a post-void residue of not more than 50 ml. So, urinary infection rate is dramatically decreased.

Humans↗

PubMed2001

[Surgical treatment of chronic subdural hematoma in the adult. Review of the literature].

There are various methods to treat chronic subdural hematomas in adults. "Open craniotomy" (craniotomy-membranectomy, burr-hole craniotomy) and "closed craniotomy" (twist-drill craniotomy, subdural tapping) are the most frequent technics, but endoscopy and shunts are also possible. No difference in results can be identified from a review of the literature. Different factors of recurrence are analysed.

Adult↗

PubMedDate not supplied

Leukemic dissemination within a glioblastoma in a patient with chronic lymphoid leukemia.

Metastasis from an extracranial tumor to a primary central nervous system tumor is a rare event, and most reported cases concern metastases to meningiomas. The authors describe the first case of leukemic cell dissemination within a glioblastoma. The patient likely presented a genetic predisposition to multiple neoplasms, and the unusual localization of leukemic cells might be partly related to the characteristic microvascular proliferation in glioblastoma.

Brain↗