PubMed Health⌕ Search

Biomedical subjects

P Gallois

Publications and source records attributed to P Gallois.

18 recordsLinked to original sources
PubMed1992

Gene rescue in plants by direct gene transfer of total genomic DNA into protoplasts.

To study the possibility of gene rescue in plants by direct gene transfer we chose the Arabidopsis mutant GH50 as a source of donor DNA. GH50 is tolerant of chlorsulfuron, a herbicide of the sulfonylurea class. Tobacco protoplasts were cotransfected with genomic DNA and the plasmid pHP23 which confers kanamycin resistance. A high frequency of cointegration of the plasmid and the genomic DNA was expected, which would allow the tagging of the plant selectable trait with the plasmid DNA. After transfection by electroporation the protoplasts were cultivated on regeneration medium supplemented with either chlorsulfuron or kanamycin as a selective agent. Selection on kanamycin yielded resistant calluses at an absolute transformation frequency (ATF) of 0.8 x 10(-3). Selection on chlorsulfuron yielded resistant calluses at an ATF of 4.7 x 10(-6). When a selection on chlorsulfuron was subsequently applied to the kanamycin resistant calluses, 8% of them showed resistance to this herbicide. Southern analysis carried out on the herbicide resistant transformants detected the presence of the herbicide resistance gene of Arabidopsis into the genome of the transformed tobacco. Segregation analysis showed the presence of the resistance gene and the marker gene in the progeny of the five analysed transformants. 3 transformants showed evidence of genetic linkage between the two genes. In addition we show that using the same technique a kanamycin resistance gene from a transgenic tobacco could be transferred into sugar beet protoplasts at a frequency of 0.17% of the transformants.

Blotting, Southern↗
PubMed1991

[Late auditory evoked potentials in subcortical cognitive deterioration].

Late auditory evoked potentials (AEPs) were recorded by the odd-ball method in 55 non-deteriorated parkinsonians (NP) and in 27 parkinsonians with cognitive deterioration (CDP), compared with 20 controls (C) and 24 patients with Alzheimer-type senile dementia (ATSD). The latency of P 300 was prolonged in the CDP and ATSD groups (410.72 +/- 24.45 and 433.62 +/- 38.30 respectively; P less than 0.001. The latency of N 100 was prolonged only in the CDP group (106.6 +/- 4.82; P less than 0.001). Late AEPs were also studied in 63 subjects with possible or confirmed disseminated sclerosis (DS) compared with 33 controls of similar mean age. The ERFC test divided these patients into 38 with non-deteriorated DS (NDS) and 25 with deteriorated DS (DDS). The latency of P 300 was prolonged in both groups: NDS 331.14 +/- 25.89; DDS 376.64 +/- 29.51 (P less than 0.001). The latency of N 100 was prolonged in the NDS group (100.25 +/- 9.20) and the DDS group (104.43 +/- 9.01). Following a study of correlations between the degree of mental deterioration and the electrophysiological parameters in these populations, the significance of the N 100 latency as electrophysiological marker of subcortical dementia is discussed.

Aged↗
PubMed1989

[Motor impersistance of the eyelids. Study of 93 cases and a discussion of pathogenic mechanisms].

In a prospective study, 252 subjects were investigated for motor impersistence of the eyelids (MIE) by means of a protocol that evaluated its intensity and detected associated signs, notably other phenomena of motor impersistence. MIE was frequent, being found in 93 subjects. It was usually observed in diffuse brain lesions, then in lesions of the right hemisphere, particularly in the posterior and deep cortex. In right hemisphere lesions, MIE was significantly associated with constructional apraxia, visual neglect and Anton-Babinski syndrome. In diffuse cerebral lesions, MIE was accompanied by other phenomena of motor impersistence on a background of dementia. In these cases the P 300 wave latency was significantly prolonged. Three main mechanisms may be regarded as responsible for the occurrence of MIE: apraxia, disturbance of the interhemispheric balance (notably in lesions of the right hemisphere) and disorders of attention (predominant in diffuse lesions). Actually, in every case MIE should be inserted in a continuum the extremities of which are represented by the above mentioned mechanisms.

Aged↗
PubMed1989

[Asymmetry of visual perceptive activity of faces and emotional facial expressions].

Eye movements were studied in 40 right-handed subjects during perception of symmetrical chimerical faces. These movements were recorded using an original system based on a differential optical method for the detection of corneal reflection and of the pupil made shiny. Under basal conditions, the first fixation was usually located in the left visual hemifield. The subjects spent more time gazing at the right hemiface (P less than 0.04). This visuo-spatial asymmetry in favour of the left hemispace was increased when the subject was requested to determine the emotional expressions of a new series of faces (P less than 0.002). Compared with basal conditions, the increase in the percentage of time spent in the left area was significant (P less than 0.035). An analysis performed on the first 3 seconds confirmed and amplified the differences observed. These results can partly be explained by reading habits and exploratory activity for symmetrical shapes. However, activation of the right hemisphere, specialized in the perception of faces and facial expressions, probably influenced visual exploration by drawing attention to the left area and favouring the left visual hemifield.

Adult↗
PubMed1988

[The delusion of place: contribution of the measurement of cerebral deficit].

The authors report the observation of a 61-year-old female patient who, following a right frontal-temporal ischemia, presented disorientation with respect to her surroundings. She was convinced during her hospital stay that her house had been transformed into a hospital. There was no evidence of intellectual confusion or deterioration, and the neuropsychological examination revealed visuo-spatial disturbances only. A low basal cerebral blood flow was found in the right anterior hemisphere which further decreased when the patient was asked where he was. It is hypothesized that confabulatory responses corresponded to a disinhibition of the left hemisphere from the control of the hemisphere dominant in dealing with visuo-spatial data.

Brain↗
PubMed1988

[Disconnection and recognition of faces. A case with lesions of the left visual cortex and the splenium].

We report the clinical findings in a case of alexia without agraphia, due to a left posterior cerebral artery infarction, in which C.T. showed occipital and splenial lesions. There were in addition a right homonymous hemianopsia and agnosia for colors, objects and pictures, with both associative and disconnective aspects. The hypothesis of an occipito-occipital disconnection, depriving the left visual associative areas of inputs, could explain this agnosia. The most striking findings in this case was, besides an anomia for faces, a peculiar difficulty to recognize her own face. The patient seemed to recognize herself. The patient spoke about herself in the third person, giving genuine autobiographical details, without being able to say: "it is me". This phenomenon is discussed in terms of disconnection: the right hemisphere sending information from the semantic field evoked by her own face, through the anterior part of the corpus callosum, to the left hemisphere. We discuss the hemispheric contribution within cognitive experience, and the role of language concerning the conscious experience in man.

Brain↗
PubMed1987

[Contribution of computerized tomography and nuclear magnetic resonance to the diagnosis of vascular dementia].

Nuclear magnetic resonance (NMR) and computerized tomography (CT) have become indispensable to the exploration of patients with vascular dementia. NMR is remarkable for its innocuity, its anatomical accuracy, its sensitivity and the three-dimensional approach it offers. CT is less sensitive, but the examinations are shorter and less costly. These two techniques seem to be about equally effective in visualizing multiple infarcts, although NMR gives a better contrast. In dementia due to multiple infarcts, the bilateral cortical and subcortical lesions coexist with moderate cortical trophy. The cerebral lacunae of lacunar dementia are better visualized by NMR; they are distributed on both sides, predominate in the frontal lobes and only produce slight cortical atrophy, less pronounced than ventricular dilatation. The main advantage of NMR is its high sensitivity in detecting early changes in the white matter, changes which are particularly perceptible in juxta- and periventricular areas in arteriosclerous subcortical leucoencephalopathy. NMR, not very specific here, does not readily separate these lesions from those of other types of leucoencephalopathy. The finding of hypodense areas at CT or of hypersignals at NMR (T2) around the ventricles may help in differentiating between vascular dementia, irrespective of its mechanism, and primary dementia.

Atrophy↗
PubMed1987

[Association of cerebral cysticercosis and multifocal glioma. Discussion of interactions].

Diagnosis in a case of cerebral parenchyma cysticercosis was based on conventional arguments described in the literature. The patient died after progression of the disease over 6 months, despite two courses of Praziquantel. Results of neuropathologic examination confirmed diagnosis of cysticercosis and the discovery of a multifocal astrocytic tumor involving mainly the periventricular regions. Possible interactions between parasitic infection and glioma are discussed but it is difficult to determine the precise role played by the parasitosis in the evolution of the tumor, the hypothesis of a simple coincidence being most likely. Periventricular images of an inflammatory nature observed after PZQ treatment should not be accepted unreservedly, and when an unfavorable course is apparent the periventricular histopathologic lesions should be compared with results of CT scan imaging qualified as periventricular in origin.

Brain Diseases↗
PubMedDate not supplied

[Correlations between delayed auditory evoked potentials and clinical evaluation of schizophrenic symptoms].

Late auditory evoked potentials (AEPs) were recorded by the "odd-ball" method in 20 schizophrenic patients according to DSM III R diagnosis criteria compared with 30 control subjects matched for sex and age. Patients were on antipsychotic medications; mean duration of illness was 3, 55 years. We have also proceeded to a clinical quantitative assessment of negative and positive symptoms of schizophrenia with Andreasen's rating scales. In the group of patients, we have observed a significant lengthening of the latency of N 1, N 2, P 3, N 3 and a decreased amplitude of N 1 and P 3. These results are in favour of an impairment of cerebral information processing probably localized in the subcortical level. Statistically significant correlations have been noticed between the anomalies of the last stages of information processing (P 3, N 3) and negative symptoms, more particularly affective flattening and attentional impairment. The disturbances of the first stages of information processing (P 2) and of automatic information processing (N 2) were related to positive symptoms, hallucinations and delusions especially. The anomalies of N 2 were also related to the sum of the global scores: an attentional impairment could be a main factor in the determinism of schizophrenia.

Adult↗
PubMedDate not supplied

[Cortical and subcortical dementia. The value of long auditory evoked potentials].

Long latency auditory evoked potentials were studied in 27 normal subjects, 19 patients with Alzheimer's Disease (A.D.) and 70 patients with Parkinson's Disease (P.D.). 17 patients with P.D. showed cognitive impairment measured by the "test rapide d'évaluation des fonctions cognitives - E.R.F.C.". The N2 and P3 peak latencies were prolonged in the demented group of P.D. compared to the non demented group P.D.. Between the electrophysiological parameters only the N1 latency prolongation distinguished the demented parkinsonian patients from the patients with A.D..

Aged↗
PubMedDate not supplied

[Skeletal and velar myoclonus with vision disorders. Efficacy of carbamazepine].

The authors report the case of a 71 year-old woman presenting right velopharyngo-laryngeal and skeletal rhythmic myoclonus, associated with visual and phasic disorders. They appeared four months after an infarct in the region of the left posterior cerebral artery. The ischemia was of temporo-occipital location, very probably extending to the region of the left red nucleus, thereby interrupting the dento-olivary pathway. Several drugs which are usually active in the treatment of myoclonus proved ineffective. But carbamazepine at a dose of 600 mg per day was effective from the third day and remained so after seven months. It would seem to act by inhibiting the occurrence of paroxystic discharges of an epileptic type in the olivary body disinhibited by the underlying lesion.

Aged↗