Biomedical subjects

J S Raul

Publications and source records attributed to J S Raul.

7 recordsLinked to original sources

PubMed2004

Human Neck Finite Element Model Development and Validation against Original Experimental Data.

This study proposes a detailed FEM of a human volunteer's neck and proceeds to an original model validation against experimental data recorded with this human volunteer. In order to evaluate the new model against existing data a successful temporal validation of the model was obtained under frontal, lateral, oblique and rear impact. New validation parameters are based on an experimental test proceeded in the frequency domain in order to extract the volunteer's Head-Neck system's modal characteristics. In depth validation of the head neck FEM is then performed by superposing the numerical and experimental frequency response function. Model optimisation in the frequency domain permitted after significant properties modification to reproduced accurately both, the neck extension mode at 1.4 Hz and the head retraction mode at 8.8 Hz. Finally the "frequency domain optimised" FEM response was superimposed with the temporal corridors provided in the literature. It must be mentioned that the model's response in the temporal domain remains inside existing corridors after this model optimisation in the frequency domain illustrating that the temporal validation is not accurate enough. This study proposes a neck model with improved geometry description and biofidelity with special attention paid to the retraction mode, a phenomenon which is often masked in the temporal domain.

Journal Article↗

PubMed2002

Determination of blood cyanide by HPLC-MS.

An original high-performance liquid chromatographic-mass spectrometric (HPLC-MS) procedure was developed for the determination of cyanide (CN) in whole blood. After the addition of K13C15N as internal standard, blood was placed in a microdiffusion device, the inner well of which was filled with a mixture of taurine (50mM in water)/naphthalene-2,3-dicarboxaldehyde (NDA, 10mM in methanol)/methanol/ concentrated (approximately 20%) ammonia solution (25:25:45:5, v/v). Concentrated H2SO4 was added to the blood sample, and the microdiffusion chamber was sealed. After 30 min of gentle agitation, 2 microL of the contents of the inner vial were pipetted and directly injected onto a NovaPak C18 HPLC column. Separation was performed by a gradient of acetonitrile in 2mM NH4COOH, pH 3.0 buffer (35-80% in 10 min). Detection was done with a Perkin-Elmer Sciex API-100 mass analyzer with an ionspray interface, operated in the negative ionization mode. MS data were collected as either TIC or SIM at m/z (299 + 191) and (301 + 193) for the derivatives formed with CN and 13C15N, respectively. Inspired by previous works dealing with the complexation of CN by NDA + taurine to form a 1-cyano [f] benzoisoindole derivative analyzed by HPLC-fluorimetry, this method appears simple, rapid, and extremely specific. Limits of detection and quantitation for blood CN are 5 and 15 ng/mL, respectively. The use of 13C15N as internal standard allows the quantitation of CN with elegance and accuracy in comparison with previously reported methods.

Chromatography, High Pressure Liquid↗

PubMed2002

Fatal overdosage with sildenafil citrate (Viagra): first report and review of the literature.

A fatal case of sildenafil citrate (Viagra) overdosage is presented. The deceased was a 56-year old male found dead at home, with a past history of diabetes mellitus, hypertension, chronic alcoholism, anxio-depressive disorders, and erectile dysfunction. The main autopsy findings were cardiomegaly (650 g) with dilated cardiomyopathy, diffuse coronary atherosclerosis with no sign of acute ischaemic disease, and extensive fibrosis of the myocardium, especially affecting the cardiac conducting tissue. As measured by HPLC/MS, sildenafil concentration in postrmortem blood (6.27 microg/mL) exceeded at least four times the highest therapeutic levels previously reported. The results are discussed in the light of the literature about the cardiovascular side effects of sildenafil, with special emphasis on the recently evidenced arrhythmogenic potential of the drug. This is the first report of a fatality caused by sildenafil overdosage.

Alcoholism↗

PubMed2001

Repeated measurements of aldicarb in blood and urine in a case of nonfatal poisoning.

A nonfatal case of poisoning involving aldicarb, an extremely toxic carbamate pesticide, is presented. A 39-year-old female ingested an unknown amount of aldicarb, together with alprazolam and sertraline. On admission to ICU (T0), she displayed marked cholinergic symptoms and a deep coma. The patient was given pralidoxime and atropine. Her condition gradually improved on days 2 and 3 and she was discharged at T0+80 h. Aldicarb was assayed by high-performance liquid chromatography on 21 blood and 8 urine samples successively taken during hospitalization. At the same time, serum pseudocholinesterase activity was followed on 21 successive samples. Blood aldicarb level was 3.11 microg/mL at T0 and peaked at T0+3.5 h (3.22 microg/mL), then followed a two-slope decay with a terminal half-life of ca. 20 h. Aldicarb was detected in all urine samples (peak level: 6.95 microg/mL at T0+31.5 h) and was still present at the time of discharge. Serum pseudo-cholinesterase activity remained low (< or = 10% of normal) until the 30th hour then rapidly increased and returned to normal after the 60th hour. The patient's clinical picture closely followed blood aldicarb levels and serum pseudo-cholinesterase activities. To our knowledge, this is the first report of an aldicarb poisoning documented by repeated measurements of the drug in the intoxicated person.

Adult↗

PubMed2000

[Intramedullary spread of a cerebral oligodendroglioma. Two case reports].

We report two cases of leptomeningeal metastatic dissemination to the spinal cord of a grade B oligodendroglioma. Diagnosis was suspected on MRI but imaging findings were nonspecific. The pathways by which the intramedullary part of the spinal is reached by metastatic cells remains controversial. In the reported cases, both frontal and cystic primary intracerebral lesions were observed. Chemotherapy after radiotherapy appears to improve outcome. Nevertheless, prognosis remains very poor.

Abducens Nerve Diseases↗

PubMed1999

[Results of cervical interbody fusion with coral grafts].

OBJECTIVES: We present the long term clinical and radiological results of a retrospective series of 46 cervical interbody fusions using coral grafts performed in 38 patients. MATERIAL AND METHODS: The patients were treated for prolapsed discs (19 cases) or cervical spondylosis (19 cases) with a clinical presentation of either radiculopathy (31 cases) or myelopathy (7 cases). We have done a post-operative clinical analysis of cervicoscapulalgia and radiculo-medullary symptoms and a radiological comparison of the change of the cervical spine angulation, the loss of height and the fusion rate at the graft site. RESULTS: The early clinical postoperative outcome showed that 10 out of 20 patients with excellent radiculo-medullary results had cervicoscapulalgia and 13 out of 18 patients with partial improvement had cervicoscapulalgia. No poor results according to our classification were noted. The late clinical outcome (average follow-up of 16 months) showed that 15 patients out of 31 had radiculo-medullary degradation and 24 presented with cervicoscapulalgia. Sixteen out of 20 patients had a loss of lordosis (range 6.2 degrees; SD 1.2) and 17 a loss of height (range 11.3%; SD 1.5). After 2 years, 13 out of 20 grafts were still hyperdense compared to the adjacent bone, and 8 had a hypodense peripheral edge. CONCLUSIONS: Coral grafts of this series have not been able to keep a physiological sagittal balance of the cervical spine, which is probably one of the essential factors to prevent postoperative cervicoscapulalgia. In the same way, the loss of height of the fused segments, by narrowing of the intervertabral foramen, may explain some further radiculo-medullary deterioration.

Adult↗

PubMed1997

Odontoid fractures in the child with neurological injury. Direct anterior osteosynthesis with a cortico-spongious screw and literature review.

Few cases of fracture of the odontoid process in children have been reported in the literature. A case with an associated severe traumatic brain injury and a suspected clinical high cervical spinal cord injury is reported here. This case is of interest because of the surgical treatment selected. A direct surgical approach was used for anterior screwing, with an excellent result. In some precisely defined circumstances, therefore, this treatment can be indicated.

Bone Screws↗