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Biomedical subjects

J P Guichard

Publications and source records attributed to J P Guichard.

At least 19 recordsLinked to original sources
PubMed2006

Influence of subjective visual vertical misperception on balance recovery after stroke.

BACKGROUND: Subjective visual vertical (SVV) perception can be perturbed after stroke, but its effect on balance recovery is not yet known. AIM: To evaluate the influence of SVV perturbations on balance recovery after stroke. METHODS: 28 patients (14 with a right hemisphere lesion (RHL) and 14 with a left hemisphere lesion (LHL)) were included, 5 were lost to follow-up. SVV perception was initially tested within 3 months after stroke, then at 6 months, using a luminous line, which the patients adjusted to the vertical position in a dark room. Mean deviation (V) and uncertainty (U), defined as the standard deviation of the SVV, were calculated for eight trials. Balance was initially assessed by the Postural Assessment Scale for Stroke (PASS), and at 6 months by the PASS (PASS6), a force platform (lateral and sagittal stability limits (LSL6 and SSL6)), the Rivermead Mobility Index (RMI6) and gait velocity (v6). Functional outcome was also assessed by the Functional Independence Measure at 6 months (FIM6). RESULTS: The scores for balance and for FIM6 were related to the initial V value: PASS6 (p = 0.01, tau = -0.38); RMI6 (p = 0.002, tau = -0.48), LSL6 (p = 0.06, tau = -0.29), SSL6 (p = 0.004, tau = -0.43), v6 (p = 0.01, tau = -0.36) and FIM6 (p = 0.001, tau = -0.49), as well as to the initial U value: PASS6 (p = 0.03, tau = -0.32), RMI6 (p = 0.02, tau = -0.35), SSL6 (p = 0.005, tau = -0.43) and FIM6 (p = 0.01, tau = -0.38). CONCLUSIONS: Initial misperception of verticality was related to a poor score for balance after stroke. This relationship seems to be independent of motricity and neglect. Rehabilitation programmes should take into account verticality misperceptions, which could be an important factors influencing balance recovery after stroke.

Adult↗
PubMed2006

Clinical correlates of cerebral water diffusion in Wilson disease.

OBJECTIVE: To investigate the course of diffusion changes in Wilson disease (WD) and to evaluate their clinical and radiologic correlates. METHODS: MRI with fluid-attenuated inversion recovery (FLAIR) and diffusion weighted images (DWI) were performed in 13 symptomatic patients with WD who had typical neurologic manifestations of the disease (sWD patients) and in 5 presymptomatic patients (psWD patients). Follow-up clinical and MRI data were obtained in 12/13 patients with sWD. Ten subjects without neurologic disease and with normal cerebral MRI were used as controls. Apparent diffusion coefficient (ADC) was measured in areas where hyperintense lesions were detected on FLAIR images and in the normal-appearing white matter. RESULTS: Hyperintense lesions were detected in all symptomatic patients on FLAIR MR images but only in 11 of 13 patients with sWD on DWI. These lesions were absent in patients with psWD. The mean ADC was found increased in the putamen, pallidum, internal capsule, mesencephalon, and within the white matter in the symptomatic group in comparison to controls. This was not observed in patients with psWD, who even had a decreased ADC in the putamen. A significant correlation was found between the increase in diffusion and the modified Rankin Scale in presence of symptoms. Moreover, the variation of the clinical scale was significantly correlated with the variation of diffusion in the putamen of symptomatic patients. CONCLUSION: A decrease in diffusion in the putamen can be detected before the occurrence of neurologic manifestations in WD. In contrast, a large increase in diffusion is detected after the occurrence of symptoms within the putamen, pallidum, internal capsule, and subcortical white matter parallel to the signal changes as seen on fluid-attenuated inversion recovery and diffusion weighted images.

Adolescent↗
PubMed2006

Evolution of subjective visual vertical perturbation after stroke.

OBJECTIVE: The perception of visual verticality is often perturbed after stroke and might be an underlying component of imbalance. The aim of this study was to describe the evolution of visual vertical (VV) perturbation and to investigate the factors affecting it. METHODS: Thirty patients with hemiplegia after a single hemispheric stroke (17 left lesioned [LL] and 13 right lesioned [RL]) were studied. Visual verticality was tested within 45 days of stroke, and then at 3 and 6 months. Subjects sat in a dark room and adjusted a luminous rod to the vertical position. The differences between patients' adjustments and vertical were calculated. The effects on VV evolution of the side, size, type, and location of the lesion were tested. RESULTS: Sixty percent of the recent stroke patients had an initial inaccurate perception of verticality, and 39% of these patients recovered during the 1st 3 months after stroke. The evolution of VV tilt depended on the side of the lesion (P = 0.01), with better recovery in LL patients. None of the other factors studied affected VV normalization. CONCLUSIONS: The poorer recovery of vertical perception after right-side stroke might be due to the predominant role of the right hemisphere in spatial cognition, and might be involved in the poorer recovery of balance after stroke in RL patients.

Adult↗
PubMed2005

Intra-arterial thrombus visualized on T2* gradient echo imaging in acute ischemic stroke.

BACKGROUND: MR signal loss related to arterial thrombosis leading to vascular susceptibility artifacts (VSA) has recently been reported on gradient echo images. The time course and sensitivity of VSA in acute stroke patients has been scarcely investigated. The aim of this study was to assess the frequency and course of VSA in acute stroke patients, to compare its sensitivity to distinct features of arterial occlusion as detected on FLAIR images or on CT scan. METHODS: Twenty-nine patients were scanned from 45 min to 6 h after stroke onset using identical MR parameters. All had an acute ischemic lesion identified on diffusion-weighted images, 25 had an occlusion of MCA or PCA confirmed by magnetic resonance angiography. RESULTS: VSA was detected in 22/25 patients having an occluded artery at the time of MRI examination. Flair disclosed a hyperintense vessel in all of these 25 cases, but CT scan revealed a hyperdense artery in only 15 cases. Follow-up studies showed that VSA can vanish or disappear after partial recanalization. When the artery remains occluded, VSA can decrease, disappear or increase in the next hours, possibly related to structural modifications of the thrombus with time. Most occlusions were due to cardiac and arterial emboli or to intracranial extension of carotid occlusion. CONCLUSIONS: VSA are frequent in the first hours of MCA or PCA occlusion in acute stroke patients. The sensitivity of VSA appears lower than the arterial hyperintensity on FLAIR images but higher than the hyperdense artery sign on CT scan. The extent and intensity of VSA can change with recanalization or structural modifications of the thrombus.

Adolescent↗
PubMed2004

[Rhinocerebral mucormycosis].

We report a case of a rhinocerebral mucormycosis with extensive cavernous sinus thrombophlebitis and internal carotid artery thrombosis. This case illustrates the usual clinical and imaging features of the disease, which is a potentially devastating infection in immunocompromised patients.

Carotid Artery Thrombosis↗
PubMed2002

Transient decrease of water diffusion in Wernicke's encephalopathy.

We report water diffusion abnormalities in periventricular areas in a patient with Wernicke's encephalopathy. The reduction in diffusion disappeared after 2 weeks of treatment with intravenous thiamine. We suggest that the restricted mobility of cerebral water is related to inflammatory lesions.

Adult↗
PubMed2002

Metabolism of tresperimus by rat aorta semicarbazide-sensitive amine oxidase (SSAO).

Tresperimus (Cellimis), a new immunosuppressive agent, is mainly eliminated in the rat through metabolism, in which the oxidative deamination of the primary amine of the drug plays a major role. We have previously demonstrated in vivo the significant involvement of semicarbazide-sensitive amine oxidase (SSAO) in this reaction. Rat aorta, a tissue with one of the highest specific SSAO activities, was tested as a new in vitro model to elucidate tresperimus metabolism, using a combination of liquid chromatography/mass spectrometry (LC/MS) and high-performance liquid chromatography (HPLC) analyses. The metabolites resulting from the main metabolic pathway of the drug were formed in rat aorta homogenates. The use of various SSAO, lysyl oxidase and monoamine oxidase inhibitors confirmed that SSAO is predominantly involved in the main site of tresperimus metabolism but also in every metabolic pathway of the drug, including deamination of tresperimus metabolites M3 (desaminopropyl derivative of tresperimus) and M6 (guanidinohexylamine). A microsomal fraction of the rat aorta was used to characterize tresperimus deamination. The moderate affinity of membrane-bound SSAO for tresperimus, with a Km value of 66 microM, was counterbalanced by a catalytic efficiency superior to that of certain physiological substrates of SSAO, such as methylamine. The rat aorta provided an interesting model with which to study tresperimus metabolism, highlighting the important role that SSAO could play as a phase I oxidative enzyme in the metabolism of certain exogenous amines at the vascular level.

Amine Oxidase (Copper-Containing)↗
PubMed2001

Aneurysmal bone cyst in the sphenoid bone: treatment with minimally invasive surgery.

Aneurysmal bone cysts are vascular lesions that destroy and expand bone. We report a recently treated case of an aneurysmal cyst of the sphenoid bone. A 14-year-old girl presented with frontal headaches, bouts of nausea, and vomiting. Computed tomography and magnetic resonance imaging showed typical features of an aneurysmal bone cyst. Arterial embolization was undertaken before surgery. The endoscopic transnasal procedure used allowed the complete removal of the aneurysmal bone cyst. This use of minimally invasive surgery makes this case of interest to surgeons of the skull base and sinuses.

Adolescent↗
PubMed2001

Involvement of semicarbazide-sensitive amine oxidase in tresperimus metabolism in human and in rat.

The metabolism of tresperimus, a new immunosuppressive agent, was investigated in vivo and in vitro in rat and in human. Two metabolic pathways were identified at each side of the molecule with two deamination reactions on the spermidine moiety and hydrolysis of the amide bond leading to the liberation of guanidinohexylamine. As the major metabolic pathway of the drug seemed to be the oxidative deamination, the capacity of different amine oxidases to metabolize tresperimus was then tested using in vivo experiments in rat and in vitro studies in rat and human plasma. The increase of tresperimus plasma levels induced by the administration of hydralazine, an irreversible in vivo inhibitor of semicarbazide-sensitive amine oxidase (SSAO), reflected the major involvement of this enzyme in tresperimus metabolism. This result was confirmed in vitro in rat and human plasma by the use of semicarbazide, a specific SSAO inhibitor. As opposed to rat plasma, human plasma may be an interesting in vitro model to study the metabolism of a drug extensively metabolized by SSAO such as tresperimus. Indeed, SSAO activity was significantly higher in human plasma than in rat plasma. The second metabolic pathway of the drug, which only occurred in rat plasma, appeared thus as the major route of tresperimus metabolism in this biological matrix.

Amine Oxidase (Copper-Containing)↗
PubMed2001

[Study of the middle ear. Value of multiplanar reconstructions in spiral tomodensitometry].

We point out the interest of computed tomographic reconstructions from spiral acquisition--particularly sagittal reconstructions--in the study of middle ear anatomy and adjacent structures: the facial canal and the chorda tympani. The reference reconstructions are axial and coronal reconstructions. So, we demonstrate the superiority of sagittal reconstructions for the visualization of the lateral process of the malleus, the body and long process of the incus, the third portion of the facial canal, and the chorda tympani. For the other structures of the middle ear and the other parts of the facial canal, these sagittal reconstructions are complementary. Besides, the best type of reconstruction to visualize the stapes and the vestibular window is the axial plane parallel to the stapes axis.

Ear, Middle↗
PubMed2000

[Arteriovenous malformations: a study of 200 cases].

OBJECTIVE: The aim of this study was to analyze the natural history of arteriovenous malformations by reviewing 200 consecutive cases observed in all localizations between 1992 and 1996 in a multidisciplinary angioma clinic. PATIENTS AND METHODS: Files concerning 200 arteriovenous malformations were reviewed with a standardized observation sheet applying the severity criteria defined by the International Society for the Study of Vascular Anomalies. We used the Schobinger staging system which includes 4 grades of severity: grade I=dormancy, grade II=expansion, grade III=destruction, grade IV=cardiac decompensation. RESULTS: There was no predominance by gender. Cephalic localizations were the most common. The malformation was present at birth as indicated by history taking in 40 p. 100 of the cases. Progression during childhood (grade II) was observed in 84 p. 100. At the first consultation, the patients generally were more often in grade II than in grade I or III. Bone destruction was observed in 3 cases, signs of cardiac decompensation in 5. Arteriovenous malformations were part of a more complex syndrome in 9 cases. We noted a flare-up in the prepuberty or puberty period in 75 p. 100 of the cases and the possible role of puberty (64 cases), trauma (39 cases) and pregnancy (25 p. 100 of the adult women). Explorations were generally completed (Doppler, arteriography) by grade II, expressing the need for a map of expanding lesions. Finally it was difficult to assess posteriorly the beneficial or deleterious effect of the often multiple treatments prescribed for these patients. DISCUSSION: The review of these 200 cases pointed out the "pediatric" nature of the problem of arteriovenous malformations in the large majority of the cases and the often misleading presentation of these vascular anomalies, particularly grade I malformations. A false aspect of capillary malformation could raise the risk of inappropriate treatment. This review also confirmed known factors of exacerbation (puberty, pregnancy, trauma) and demonstrated the severity of these vascular anomalies which can progress with loco-regional expansion and invasion without a cellular proliferation component. The analysis of treatments used showed that embolization alone cannot definitively and totally control a superficial arteriovenous malformation and that no one treatment, even combined embolization and large excision, can be a guarantee to provide total cure.

Adolescent↗
PubMed2000

A new formulation of fenofibrate: suprabioavailable tablets.

The rationale for, and development of, a new suprabioavailable fenofibrate tablet formulation is described. The new suprabioavailable tablet formulation combines well-established micronisation technology with a new micro-coating process. The new formulation provides more predictable and reliable drug absorption. Owing to the strong relationship between the fenofibrate dissolution performance and its oral bioavailability, equivalent plasma levels of active principal are achieved at a lower dose, with less inter-subject variability and a reduced food effect. The new suprabioavailable tablet may, therefore, be a more efficient and better tolerated formulation.

Biological Availability↗
PubMed1999

Deep cerebral venous thrombosis: imaging in eight cases.

Deep cerebral venous thrombosis (DCVT) is a rare, potentially fatal disease. We carried out a retrospective analysis of eight patients presenting with DCVT, using CT and MRI data. Digital subtraction angiography (DSA), MR angiography (MRA) (2D phase-contrast), and angiography were performed in four, four and two patients, respectively. Direct (venous abnormalities) and indirect (parenchymatous involvement) signs of thrombosis were assessed. Follow-up MRI and MRA were performed on two patients. CT was initially normal in two patients, demonstrated a "cord sign" in deep veins in five and deep venous infarcts in three. When performed within a week of admission (seven patients), MRI showed thrombosis as into intense or high signal in deep veins on sagittal T1-weighted spin-echo images in all patients, and on axial T2-weighted spin-echo images in two. Deep venous infarcts were found in five patients. Direct or indirect signs of sagittal or lateral sinus thrombosis were present on CT in two patients and on MRI in five. CT angiography, MRA and DSA were concordant with MRI findings. CT venography showed persistent flow in thrombosed veins. MRI follow-up demonstrated progressive deep venous recanalisation.

Adolescent↗
PubMed1999

Comparison of the pharmacokinetics of 17 beta-estradiol after a single 4-day application of Oesclim 50, Oesclim 100, and Vivelle 0.05 (Menorest 50) transdermal delivery systems.

Oesclim (Laboratoires Fournier, Dijon, France), also known as Esclim or Esclima, is a new estradiol transdermal delivery system (TDS) developed for the treatment of menopausal vasomotor symptoms. This open, randomized, three-way crossover study compared in 24 healthy postmenopausal women the pharmacokinetics of estradiol after a single 4-day application of Oesclim 50, Oesclim 100, and Vivelle 0.05 (CibaGeneva Pharmaceuticals, Summit, NJ; known as Menorest 50 in Europe, Rhône-Poulenc Rorer) on the upper buttock. Serum estradiol concentrations were determined by a validated radioimmunoassay method from samples taken before and during each TDS application. The concentration-time profiles for Vivelle 0.05 and Oesclim 50 were comparable with a similar absorption rate, giving a maximum concentration (Cmax) of 49 and 53 pg/mL above baseline, respectively, followed by a plateau throughout the 96-hour application period. At the end of this period, mean corrected estradiol concentrations were 18 and 19 pg/mL, respectively. The estradiol serum concentrations obtained after an application of Oesclim 100 were approximately twice as high than with Oesclim 50. All products were well tolerated, but skin intolerance was more frequent with Vivelle 0.05 (4 patients; four reports) and Oesclim 100 (3 patients; three reports) than with Oesclim 50 (none). Problems of imperfect adhesion were more than five times as frequent with Vivelle 0.05 (44%) than with Oesclim (8%).

Administration, Cutaneous↗
PubMed1999

[Tuberculosis of the central nervous system. MRI features and clinical course in 12 cases].

OBJECTIVE: The aim of this study was to characterize the MR findings of various intracranial lesions in the central nervous system (CNS) tuberculosis. MATERIALS AND METHODS: The MRI findings (T1, T2 and T1 sequence after contrast) of 12 proved cases (10 males, 2 females, 24 to 64 years old, average: 35) of CNS tuberculosis were reviewed; 4 patients were seropositive for HIV. RESULTS: Several types of lesions were identified: tuberculomas called miliary lesions if they were smaller than 2 mm in diameter (7 cases), in 1 case the tuberculoma was revealed by two large lesions and bi-hemispheric localisations, leptomeningitis (5 cases), infarction (4 cases), abscesses (3 cases with solitary lesions in 2/3 cases), hydrocephalus (3 cases), pachymeningitis (2 cases). A tuberculomas-leptomeningitis association was found in 4 patients. The pachymeningitis form had an unusual aspect in one case. Patients with leptomeningitis showed thick meningeal contrast enhancement involving all basal cisterns, expanding to the sylvian fissures level, and causing narrowing of the sylvian arteries. Massive infarctions resulted from arterial englobement or embols. In three out of five patients, leptomeningitis was the initial presentation. In seropositive patients, tuberculosis was severe with high mortality (3/4 patients), and associated with other multiple lesions. CONCLUSION: Central nervous system tuberculosis has different appearances, mostly tuberculomas and leptomeningitis. MR with contrast is necessary for follow-up during treatment.

Adult↗