Search PubMed⌕ Search

Biomedical subjects

J D Degos

Publications and source records attributed to J D Degos.

At least 37 records · Page 2Linked to original sources
PubMed1998

Multiple-domain dissociation between impaired visual perception and preserved mental imagery in a patient with bilateral extrastriate lesions.

A brain-damaged patient is described whose pattern of performance provides insight into both the functional mechanisms and the neural structures involved in visual mental imagery. The patient became severely agnosic, alexic, achromatopsic and prosopagnosic following bilateral brain lesions in the temporo-occipital cortex. However, her mental imagery for the same visual entities that she could not perceive was perfectly preserved. This clear-cut dissociation held across all the major domains of high-level vision: object recognition, reading, colour and face processing. Our findings, together with other reports on domain-specific dissociations and functional brain imaging studies, provide evidence to support the view that visual perception and visual mental imagery are subserved by independent functional mechanisms, which do not share the same cortical implementation. In particular, our results suggest that mental imagery abilities need not be mediated by early visual cortices.

Aged↗
PubMed1998

Inversion superiority in visual agnosia may be common to a variety of orientation polarised objects besides faces.

Selective impairment in recognition of faces (prosopagnosia) resulting from certain localized cortical lesions has been advanced as an argument for a face specific brain module. The argument is claimed to be strengthened by the discovery of an inversion superiority effect in the recognition of faces by a prosopagnosic patient (Farah et al., Vis Res 1995b;35:2089-2093). The present paper reports an inversion superiority effect in the recognition of faces and shoes in a visual agnosic patient. The finding raises the possibility that several classes of orientationally polarized objects, of which shoes and faces are examples, will exhibit inversion superiority.

Aged↗
PubMed1998

Circulating transforming growth factor beta 1 (TGF-beta1) in Guillain-Barré syndrome: decreased concentrations in the early course and increase with motor function.

OBJECTIVE: To delineate the possible implication of the immunosuppressive cytokine transforming growth factor beta 1 (TGF-beta1) in the pathogenesis of Guillain-Barré syndrome. Guillain-Barré syndrome is a disorder that may implicate cytokines in its pathogenesis. TGF-beta1 is a potent anti-inflammatory cytokine occasionally shown to be regulated in the course of demyelinating disorders. METHODS: The study measured circulating proinflammatory and anti-inflammatory cytokines from the progressing phase to early recovery in patients with Guillain-Barré syndrome. Plasma concentrations of TNF-alpha, IL-beta1, IL-2, IL-4, IL-6, IL-10, and TGF-beta1 were prospectively evaluated in 15 patients with Guillain-Barré syndrome every three days for the first 15 days after admission to hospital, and in 15 controls with non-inflammatory neurological diseases. RESULTS: Concentrations of TGF-beta1 in plasma were decreased in 13115 patients (87 %) at day 1, remained low during progression and the plateau of paralysis (days 1-10), and then progressively increased up to control concentrations during early recovery (days 12-15). Concentrations of plasma TGF-beta1 correlated positively with motor function, the lowest values being e found in the most disabled patients. Concentrations of plasma TGF-beta1 were decreased before any treatment, and during treatment by either plasma exchange or intravenous immunoglobulins, plasma exchange being associated with a more pronounced decrease in TGF-beta1 at day 7. Circulating TNF-alpha concentrations were raised, as previously reported, when other cytokines were either randomly increased (IL-2, IL-6), or undetectable (IL-1, IL-4, IL-7, IL-10). CONCLUSIONS: Down regulation of TGF-beta1 in the early course of Guillain-Barré syndrome could participate in neural inflammation.

Adjuvants, Immunologic↗
PubMed1998

Disruption of residual reading capacity in a pure alexic patient after a mirror-image right-hemispheric lesion.

A 74-year-old woman became a letter-by-letter reader after the occurrence of a left occipito-temporal hematoma. Seven months later, she suffered a second, mirror-image hematoma in the right hemisphere. After this second lesion, her residual reading capacity deteriorated dramatically in terms of both accuracy and reading latencies for words and isolated letters. Our findings support the hypothesis that the right hemisphere contributes to the residual reading capacities of pure alexic patients.

Aged↗
PubMed1998

Right-side neglect in Alzheimer's disease.

Unilateral neglect--the inability to pay attention to events occurring on one side of space--usually occurs for left-side events after focal right-hemisphere damage. We report a 73-year-old woman with probable AD and no evidence of focal brain lesions who showed signs of right-side neglect and extinction. Neglect was more severe after 1 year. Neuroimaging techniques demonstrated an asymmetry of cortical involvement, with cortical atrophy and hypoperfusion predominant in the left posterior regions. Unilateral neglect should be assessed systematically in AD.

Aged↗
PubMed1998

[Pointing and its object: towards the neuropsychology of objectivation].

We describe a disorder similar to body-image agnosia or autotopagnosia characterized by the inability to designate targets situated outside the body. This disorder, which we have termed allotopagnosia, occurs exclusively in subjects with a lesion involving the posterior region of the left parietal lobe. The most common manifestation is the designation of parts of the body of another person as being part of the patient's own body (heterotopagnosia with self-designation). This disorder cannot be explained by aphasia, apraxia, or visuomotor dysfunction nor by an inability to identify parts of the body as self. Patient's expression of the confusion between their own body with that of others and the gestures they use to designate indicate a relationship with reality (non-self and target) confined to the human species. The disorder appears in children at the same time as language acquisition. This suggests the hypothesis that allotopagnosia results from a deficit or dysfunction of the left parietal lobe where outside elements are attributed to situations and identities independent of self.

Agnosia↗
PubMed1997

All-trans retinoic acid in relapsing malignant gliomas: clinical and radiological stabilization associated with the appearance of intratumoral calcifications.

PURPOSE: To evaluate the therapeutic effect of all-trans retinoic acid (ATRA) with and without cytosine arabinoside in relapsing malignant gliomas. PATIENTS AND METHODS: 9 patients (8 male, 1 female, age 53.9 +/- 11.2) with relapsing malignant gliomas (grade IV:6; grade III:3) were treated by ATRA 1 to 21 months after the end of their initial treatment. ATRA was given unceasingly during 2 to 17 months at 90 mg/d. In 6 patients it was associated to cytosine arabinoside (4 g/course, 1 to 9 courses every 4 weeks). RESULTS: 4 non-responder patients died 2.5 to 4 months after starting therapy. One patient who had been reoperated before receiving ATRA and cytosine arabinoside (5 course) had no sign of tumor recurrence after 17 months of treatment. In 4 responder patients (2 glioblastoma and 2 anaplastic astrocytoma) a clinical and radiological stabilization (time to progression) during 9 +/- 2.5 months was observed. This stabilization was associated in 3 of them with the appearance of intra tumoral calcifications visualized on repeated CT scans and confirmed in one patient by post-mortem examination. All of them had received cytosine arabinoside (1 to 9 courses) with ATRA; however small calcifications were also observed in one non-responder patient who did not receive aracytine. CONCLUSION: These results suggest: a) a therapeutic effect of ATRA in combination with cytosine arabinoside in patients with relapsing malignant gliomas b) that intratumoral calcifications are related to the effects of ATRA on differentiation and/or on endothelial t-PA production and that these effects explain the tumor progression arrest in responder patients. The transient efficiency is probably related to the pharmacokinetics of ATRA or to changes of cellular mechanisms that modulate the cell response to the drug and is a critical issue for this therapy.

Adult↗
PubMed1996

Overproduction of proinflammatory cytokines imbalanced by their antagonists in POEMS syndrome.

The polyneuropathy, organomegaly, endocrinopathy, M protein, skin changes (POEMS) syndrome is a rare multisystem disorder of obscure pathogenesis associated with osteosclerotic myeloma. Circulating levels of proinflammatory cytokines (tumor necrosis factor-alpha (TNF-alpha) interleukin-1 beta [IL-1 beta], IL-2, IL-6, and interferon-gamma [IFN-gamma]), anti-inflammatory cytokines (transforming growth factor beta 1 [TGF beta 1], IL-4, IL-10, and IL-13), the cytokine carrier protein alpha 2 macroglobulin, IL-1 receptor antagonist (IL-1ra), soluble TNF receptors (sTNFr) p55 and p75, and soluble IL-6 receptor (sIL-6r) were determined in 15 patients with POEMS syndrome and 15 with multiple myeloma. Patients with POEMS syndrome had higher serum levels of IL-1 beta, TNF-alpha, and IL-6 and lower serum levels of TGF beta 1 than did patients with multiple myeloma. Serum levels of IL-2, IL-4, IL-10, IL-13, IFN-gamma, alpha 2 macroglobulin, and sIL-6r were similar in both groups. IL-1ra and sTNFrs were increased in POEMS syndrome, but out of proportion to the increase of IL-1 beta and TNF-alpha. Serial evaluations in 1 patient showed that proinflammatory cytokine serum levels paralleled disease activity assessed by platelet count and neurologic involvement. Our results suggest that the manifestations of POEMS syndrome might be regarded as the result of a marked activation of the proinflammatory cytokine network (IL-1 beta, IL-6, and TNF-alpha) associated with a weak or even decreased (TGF beta 1) antagonistic reaction insufficient to counteract the noxious effects of cytokines.

Adult↗
PubMed1996

All-trans-retinoic acid in POEMS syndrome. Therapeutic effect associated with decreased circulating levels of proinflammatory cytokines.

Chronically elevated serum levels of proinflammatory cytokines is a feature of the syndrome known as POEMS (plasma cell dyscrasia with polyneuropathy, organomegaly, endocrinopathy, monoclonal [M] protein, skin changes). A patient had a POEMS syndrome with thrombocytosis and biclonal gammopathy and was treated as follows: all-trans-retinoic acid (tretinoin) at 90 mg/day for 50 days, no treatment for 70 days, readministration of tretinoin at 75 mg/day for 180 days. Focal bone lesion irradiation was performed from day 26 to day 50. Serum levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF alpha), and IL-1 beta normalized within 7 days after the first administration of tretinoin, transiently increased at the time of radiotherapy, increased again after withdrawal of the tretinoin, and decreased again after its reintroduction. The platelet count and gammopathy paralleled the changes in the cytokine levels. This study documents in vivo the ability of all-trans-retinoic acid to down-regulate the release of IL-6, IL-1 beta, and TNF alpha, and illustrates its potential as a therapeutic agent in conditions associated with chronic overproduction of proinflammatory cytokines.

Cytokines↗
PubMed1996

Improvement of severe postural cerebellar tremor in multiple sclerosis by chronic thalamic stimulation.

Tremor can be particularly disabling in patients with multiple sclerosis (MS) and is mildly improved by drug treatment. The efficiency of stereotactic thalamotomy has been reported in a small number of patients but was counterbalanced by severe postoperative complications. Stimulation of the thalamic ventral intermediate nucleus, which is a less aggressive surgical method, is efficient in essential and in parkinsonian tremors. We report here the results of thalamic stimulation in 13 patients with MS with tremor. All patients were subjected to clinical examination, videorecording, and quantification of the functional disability before surgery and 3 months postoperatively. The surgical intervention was well tolerated in all cases. A clear improvement of the tremor was observed in 69.2% of the patients. Functional improvement was more varied and depended on the severity of tremor and coexistence of other neurological symptoms. Of the eight most severely affected patients, seven recovered the possibility to easily catch an object and use it. The results indicate that thalamic stimulation may be useful in the treatment of severe postural cerebellar tremor in MS.

Adult↗
PubMed1996

Long-term outcome of unilaterally transplanted parkinsonian patients. I. Clinical approach.

Five patients with Parkinson's disease, unilaterally transplanted with foetal mesencephalic cells into putamen (n=1) or putamen and caudate (n=4), were followed throughout a period of 15-36 months after surgery, according to the recommendations of the core assessment programme for intracerebral transplantations (CAPIT). All these patients exhibited an increase in the fluorodopa uptake in the grafted putamen, which was most significant in the first and last patient of the series. Long-term bilateral improvement of skilled hand movements was observed, starting between the third and sixth month after grafting, and confirmed by the statistical analysis of CAPIT timed tests. A mild to moderate effect on the amount of 'off' time and 'on-off' fluctuations was observed, whereas, apart from one case, no other clear effect on gait, walking and speech was found. One patient included in the study, already suffering slight cognitive impairment, clearly exhibited progression of a dementia process after surgery. Daily living activities were clearly improved in only one of the other four patients. At the end of the study period, all patients needed L-dopa therapy at a similar or higher dose than before grafting, but, in most of them, other dopaminergic drugs were reduced or stopped. All patients exhibited bilateral dyskinesias before grafting that were greatly decreased in intensity a few months after surgery. Delayed asymmetrical dyskinesias, occurring on the side displaying the better motor improvement, i.e. contralateral to the graft, were observed in three patients. These results suggest that neural transplants may influence two central mechanisms involved in motor function and the onset of dyskinesias. These effects are likely to occur through complex interactions with the post-synaptic dopaminergic receptors. The occurrence of dyskinesias might simply reflect increased presynaptic storage and release of dopamine. Alternatively, it might, in part, represent some other long-term deleterious effect of the graft. Since PET-scan data indicate that the reinnervation obtained is sub-optimal, it will be of interest to obtain a larger and denser reinnervation of the host striatum and to try, thereafter, to reduce the dose of L-dopa.

Aged↗
PubMed1996

[Neuropsychological testing of 5 patients with Parkinson's disease before and after neuron graft].

Five patients with idiopathic PD were followed by neuropsychological tests after brain fetal neuronal transplantation. The following tests were used in order to assess memory as well as visuospatial and frontal functions: MMSE, Mattis Scale, Wisconsin Card Sorting Test, Stroop task, word fluency tasks, 15-objects test, WAIS-R (Digit span, Arithmetic, Block design, Pictures completion, Pictures arrangement), learning of 15 words of Rey, WMS-R (Logical memory) and Visual memory of L. Israël. The same tests were performed before, then one year following the transplantation. Pooled data did not show any significant difference between pre and post-operative tests. Individual results varied among patients: 2 remained unchanged, 1 had a pathological deterioration which increased after one year, 1 had some frontal symptoms whereas the last patient improved. Our data confirm that this surgical procedure do not induce permanent neuropsychological deficits, but do not indicate at the present time any clear effect of dopamine reinnervation on cognitive functions.

Aged↗
PubMed1995

Creutzfeldt-Jakob disease after liver transplantation.

We report a 57-year-old woman who died from Creutzfeldt-Jakob disease 2 years after a liver transplantation. The liver donor had no history of neurological disease. In one albumin donor, possible Creutzfeldt-Jakob disease developed 3 years later. The patient initially had cerebellar symptoms. Neuropathology included "Kuru-type" plaques and prion protein (PrP) deposits involving the cerebellum predominantly. The patient was homozygote valine at codon 129 of the PrP gene while the liver was homozygote methionine. This observation raises the possibility of transmission of Creutzfeldt-Jakob disease by the graft itself or the associated albumin transfusions and, on a wider extent, by nonneural tissue.

Creutzfeldt-Jakob Syndrome↗
PubMed1995

Striatal dopaminergic denervation in pallidopyramidal disease demonstrated by positron emission tomography.

Pallidopyramidal disease is a rare disease of young patients in which they manifest a parkinsonian syndrome and pyramidal signs. Pallidopyramidal disease has been attributed to a degeneration of the pallidum and the pyramidal tract, although only 1 patient has been studied postmortem. In the present report, [18F]fluorodopa positron emission tomography in 2 patients showed a marked dopaminergic denervation of the striatum, suggesting that this disease corresponds more to a nigropallidopyramidal dysfunction.

Adolescent↗