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Biomedical subjects

J Perret

Publications and source records attributed to J Perret.

At least 91 records · Page 5Linked to original sources
PubMed1988

[Magnetic resonance imaging in horizontal oculomotor paralysis caused by infarction].

Four patients with focal brainstem ischemic strokes and various types of horizontal oculomotor disturbances have been studied clinically and radiologically. One had a six nerve palsy, one a unilateral internuclear ophthalmoplegia, one a Fisher's one-and-a-half syndrome, and one a paramedian pontine reticular formation syndrome with a sixth nerve palsy. In all patients a C.T. Scan and a Magnetic Resonance Imaging (MRI) were obtained. The MRI study was performed on a CGR Magniscan 5000 with a superconducting magnet of 0.5 Tesla. In all patients a hypersignal in T2 weighted images was shown and corresponded to the brainstem infarct. MRI allowed accurate delineation of the lesion and clinico-radiologic correlations in three patients. But the low specificity of MRI does not permit to distinguish edema from necrosis, gliosis or demyelination in a region with a pathological MRI signal. In one patient this low specificity and perhaps partial volume effects decreased the accuracy of the clinico-topographic correlation.

Abducens Nerve↗
PubMed1988

[Contribution of oculography and magnetic resonance imaging to the clinico-topographic correlates in ischemic vascular disorders of the brainstem].

6 patients with brainstem infarction and oculomotor signs were studied. One case was consistent with a mesencephalic infarct (internuclear ophthalmoplegia); 4 cases were consistent with a protuberantial infarct (3 cases of "one and a half" syndrome and one case of pontine reticular syndrome associated with a palsy of the root of the VIth nerve. One case was a laterobulbar syndrome. These 6 patients were studied with CT scan and magnetic resonance imaging (MRI CGR Magniscan 5000 with supraconductor magnet of 0.5 Tesla) with T2 weighted images (TR = 2000 ms, TE = 60; 120 ms) in joined section of 9 or 6 mm thickness. The MRI findings were in each case consistent with an infarction. The clinico-topographic correlations are compared with the oculographic findings.

Brain Ischemia↗
PubMed1988

[Magnetic resonance imaging and laterobulbar infarction].

Six patients with a clinical diagnosis of lateral medullary infarction have been studied by CT scan and Magnetic Resonance Imaging (MRI). The MRI study was performed on a CGR Magniscan 5000 with a superconducting magnet of 5 Tesla. In all patients T2 weighted images (TR = 2000, TE 60, 120) in joined section of 9 or 6 mm thickness were obtained in the axial plane. Three patients were also studied in T1 weighted sequences (TR = 500, TE = 28). A lateral medullary infarct was shown in 5 patients. MRI findings were consistent with a hemorrhagic infarct in one case. Occlusion of a vertebral artery was suggested in 2 cases and was confirmed by angiography. In 3 cases, an associated ipsilateral cerebellar infarct was demonstrated. The CT scan had only shown bleeding in the medulla oblongata in the hemorrhagic infarction case, and a cerebellar infarction in another case. Some clinical manifestations are discussed with regard to the results of MRI. MRI appears as the best current method to improve clinico-topographic correlations in medullary infarcts.

Aged↗
PubMed1987

Clinical and biochemical effects of gamma-vinyl Gaba in tardive dyskinesia.

Clinical and biochemical effects of Gamma-vinyl-Gaba (GVG) have been evaluated in a blind video-controlled study in 10 psychiatric patients (mean age 71 yr) with tardive dyskinesia. CSF free and total Gaba and homocarnosine concentrations increased from three to five fold with GVG treatment. Despite the GVG-induced biological effects on Gaba metabolism, GVG did not consistently improve tardive dyskinesia. Psychomotor side-effects occurred in older patients, who only tolerated GVG dosages of 2-4 g/day.

Aged↗
PubMed1987

[Ataxic hemiparesis caused by a thalamic lacuna].

A 64 year old man was admitted for an ataxic hemiparesis. Magnetic resonance imaging (MRI) suggested a lacunar infarct. The lesion was located in the postero-lateral part of the contralateral thalamus, sparing the internal capsule.

Cerebellar Ataxia↗
PubMed1986

[Magnetic resonance imaging in multiple sclerosis. Sensitivity and correlation with the clinical picture].

The aim of imaging the brain in Multiple Sclerosis (MS) is to prove the dissemination of lesions, so critical for the diagnosis and so difficult to ascertain clinically. Our study included 21 patients with clinically definite (12) and probable (9) MS. A 21 patients underwent a neurological standard examination, a double-dose delayed CT scan and a Magnetic Resonance Imaging with a superconducting 0.5 Tesla magnet. Jointed slices were performed with a T2-weighted Spin-Echo sequence (TE 60, 120; TR 2000 msec). MRI detected 640 lesions in 20 patients while CT scan detected only 24 lesions in 9 patients. Technical limiting factors are discussed. Abnormalities in MRI were high-intense spots, blotches and streaks, located predominantly in the periventricular area. Capping lesions were common around the ventricular horns. "Plaques" were visualized in the posterior fossa. For each patient, the total surface of the lesions was calculated and was found to be related with the presence of lesions and with the cortical atrophy on CT scan. A correlation between the surface of lesions calculated by MRI and the disability scale was found especially in the group of patients with clinically proven cerebral lesions, while patients with predominantly spinal forms had a significantly lower surface of lesions. This finding could yield a new quantitative evaluation of the MS pathologic process which could be used to assess therapeutic efficacy.

Adult↗
PubMed1985

Effects of tiapride in tardive dyskinesia.

Tiapride, a selective D2 dopaminergic receptor blocking agent from the substituted benzamide class, was evaluated in a blind video-controlled trial in 10 psychiatric patients with tardive dyskinesia. There was a significant decrease in dyskinesia with a parallel increase in parkinsonism. This relationship between two opposite effects on movement suggests a common pathophysiological basis lying on a reciprocal hyper- and hypoactivity of the dopaminergic striatal system. Nevertheless, other mechanisms may be involved, for the evolution of individual parkinsonian and dyskinesia scores is not necessarily opposite: the tiapride-induced parkinsonism was generally acceptable and in two cases, the dyskinesia scores were reduced without an increase in parkinsonism. Therefore, more dyskinetic patients have to be evaluated in long-term studies with tiapride, before this drug could be recommended in tardive dyskinesia, when dyskinetic movements become intolerable.

Adult↗
PubMed1985

Herpes simplex virus ribonucleotide reductase induced in infected BHK-21/C13 cells: biochemical evidence for the existence of two non-identical subunits, H1 and H2.

In nearly all systems studied, ribonucleotide reductase consists of two non-identical subunits. We present here the results of our study on herpes simplex virus (HSV) ribonucleotide reductase in favour of the existence of two subunits, H1 and H2, different from the mammalian subunits, M1 and M2. First, although the viral subunits could not be separated by Blue Sepharose chromatography (unlike mammalian subunits), they seemed to dissociate at very low protein concentration as suggested by the non-linear relationship between activity and low protein concentration. Second, pyridoxal phosphate (Pyr.P)-NaBH4 treatment and 4-methyl-5-amino-1-formylisoquinoline thiosemicarbazone (MAIQ) treatment of partially purified extract of mammalian ribonucleotide reductase which inactivated M1 and M2 respectively also inhibited the HSV ribonucleotide reductase. This activity could be restored by mixing Pyr.P-NaBH4-treated extracts with MAIQ-treated extracts of viral ribonucleotide reductase, suggesting that each treated extract contains one active subunit. Moreover, the addition of exogenous M1 or M2 subunits to one or the other of these two treated extracts did not produce any detectable reductase activity. Our interpretation of these results is that the two subunits H1 and H2 which could dissociate upon treatment did not form enzymically active hybrids with the mammalian subunits. Also, the higher degree of resistance to heat inactivation and to hydroxyurea of the viral reductase as compared to the mammalian enzyme suggests that H1 differs from M1 and H2 from M2.

Animals↗
PubMed1985

[Isolated ipsilateral lateropulsion caused by bulbar hematoma].

A case of hematoma involving probably the reticular formation of the medulla oblongata is reported. Examination showed a soft palate paresis and an ipsilateral axial lateropulsion without vertigo or oculomotor disorders. The mechanism of the lateropulsion is discussed. During the spontaneous recovery a transient hydrocephalus was observed.

Aged↗
PubMed1985

[Left anterior choroidal artery syndrome with language disorders and constructional apraxia].

The infarction in the territory of the anterior choroidal artery may induce a sensory motor impairment and neuropsychological symptoms close to those observed in some thalamic lesions. In a right handed man with a left sided infarction, language disturbances and constructional apraxia were observed. Cerebral blood flow measurements were performed 4 days after the stroke with the 133Xenon inhalation method. A decrease of mean hemispheric values was observed on both sides but more so on the left hemisphere, in the left frontoparietal regions. 98 days after the stroke language and constructional apraxia have partially improved. We have drawn a parallel between blood flow variations and neuropsychological signs. The cortical deafferentation caused by the interruption of the thalamo-cortical projections may explain the focalized decrease in cerebral blood flow values in the left hemisphere.

Adult↗
PubMed1984

Pursuit gaze and the occipitoparietal region. A case report.

A patient lost smooth pursuit gaze to the side opposite a right occipitoparietal hemorrhage. Saccadic gaze was preserved. Pursuit gaze broken by saccades was present toward the side of the lesion. Optokinetic nystagmus (OKN) was defective when a tape was moved toward the patient from the hemianopic fields. Within two weeks, the contralateral pursuit gaze defect had cleared; however, the visual field and OKN defects and the ipsilateral pursuit gaze abnormality persisted.

Aged↗
PubMed1984

[Paralysis of the hypoglossal nerve caused by 2 aneurysms and a dissecting aneurysm of the internal carotid artery].

Palsies of the lower cranial nerves caused by a compressive pathological carotid artery are not common. Three cases of paralysis of the hypoglossal nerve, hypoglossal and vagus, hypoglossal, glossopharyngeal and vagus nerves, are reported. In 2 patients the symptoms were related to an extracranial carotid artery aneurysm below the base of the skull and in 1 patient to a spontaneous carotid dissecting aneurysm. It is possible that some localized arterial dissecting aneurysms evolve to a localized aneurysmal sac, especially if they are located between Cl and the base of the skull. The tongue paralysis disappeared in 2 patients.

Adult↗
PubMed1983

[Electromyographic study of 4 lip muscles and acoustic findings in parkinsonian dysarthria].

The articulatory E.M.G. activity of lower lip muscles was investigated in 3 patients with Parkinson's disease and compared with normal subjects. Four paired muscles were recorded because of their antagonist function: 1) Orbicularis oris inferioris and depressor labii inferioris; 2) mentalis and buccinator. All patients evidenced well defined E.M.G. abnormalities. These consisted in the impairment of the functional organization of the antagonist muscles (lack of reciprocal inhibition), the existence of both a resting activity between utterances and a sustained hypertonic background activity during the utterance. This study was focused on the E.M.G. activity without concomitant observation of lip movement. Parallel oscillographic records of speech acoustic signals confirmed the characteristics of the voice of parkinsonian patients: low and uniform intensity, poor timbre, irregular speech rate and abnormalities of pitch.

Aged↗