72 research outputs found

    Severe ischemic retinopathy in a patient with systemic lupus erythematosus without antiphospholipid syndrome: A case report

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    AbstractSystemic lupus erythematosus (SLE) is a chronic, autoimmune, multisystem disease which may affect the eyes and/or visual system in up to a third of patients. Severe retinal vaso-occlusive diseases have been rarely reported as manifestation in patients with SLE. We report the case of a 35-year-old female treated for systemic lupus erythematosus for 6months, presented a sudden loss of vision. Fundus examination and fluorescein angiography revealed severe retinal vascular occlusion. This has motivated the search for antiphospholipid antibody syndrome and this was confirmed without the presence of anticardiolipin antibodies. And the treatment consisted in a laser therapy. The purpose of this case report is to demonstrate that an ocular vascular event can reveal the disease and that its diagnosis is important because this disease generally affects young people and may endanger ocular and vital prognosis

    Rétinopathie diabétique : quand opérer ?

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    Activity in ventral premotor cortex is modulated by vision of own hand in action

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    Parietal and premotor cortices of the macaque monkey contain distinct populations of neurons which, in addition to their motor discharge, are also activated by visual stimulation. Among these visuomotor neurons, a population of grasping neurons located in the anterior intraparietal area (AIP) shows discharge modulation when the own hand is visible during object grasping. Given the dense connections between AIP and inferior frontal regions, we aimed at investigating whether two hand-related frontal areas, ventral premotor area F5 and primary motor cortex (area F1), contain neurons with similar properties. Two macaques were involved in a grasping task executed in various light/dark conditions in which the to-be-grasped object was kept visible by a dim retro-illumination. Approximately 62% of F5 and 55% of F1 motor neurons showed light/dark modulations. To better isolate the effect of hand-related visual input, we introduced two further conditions characterized by kinematic features similar to the dark condition. The scene was briefly illuminated (i) during hand preshaping (pre-touch flash, PT-flash) and (ii) at hand-object contact (touch flash, T-flash). Approximately 48% of F5 and 44% of F1 motor neurons showed a flash-related modulation. Considering flash-modulated neurons in the two flash conditions, ∼40% from F5 and ∼52% from F1 showed stronger activity in PT- than T-flash (PT-flash-dominant), whereas ∼60% from F5 and ∼48% from F1 showed stronger activity in T- than PT-flash (T-flash-dominant). Furthermore, F5, but not F1, flash-dominant neurons were characterized by a higher peak and mean discharge in the preferred flash condition as compared to light and dark conditions. Still considering F5, the distribution of the time of peak discharge was similar in light and preferred flash conditions. This study shows that the frontal cortex contains neurons, previously classified as motor neurons, which are sensitive to the observation of meaningful phases of the own grasping action. We conclude by discussing the possible functional role of these populations

    Cortical connections of the macaque caudal ventrolateral prefrontal areas 45A and 45B

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    We have found that the 2 architectonic subdivisions of the prefrontal area 45, 45A and 45B, display connectivity patterns that clearly distinguish them from one another and from their neighboring architectonic areas. Area 45A is primarily connected to the frontal areas 45B, 12l, caudal 12r, 12o, 10, rostrodorsal 46, 9/8B, 44, 8/FEF (frontal eye field), and the SEF (supplementary eye field), temporal area IPa, and unique among all the studied areas, to the superior temporal polysensory (STP) area and auditory parabelt areas. Area 45B displayed much stronger frontal connections with the oculomotor areas 8/FEF, 8r, and the SEF than those of area 45A, primary connections with areas 12l, caudal 12r, 12o, and 8B, and unlike area 45A, with areas ventrorostral 46, rostral 12r, 12m, and 13m. Temporal connections were all virtually confined to areas IPa, intermediate TEa/m, and TE. Additional labeling was found in lateral intraparietal area. Our data suggest that 45A and 45B are 2 distinct areas, possibly playing a differential role in nonspatial information processing: area 45A corresponds to the prefrontal sector for which a role in communication behavior and homology with the human area 45 was proposed, whereas area 45B is a distinct prearcuate area, possibly affiliated to the oculomotor frontal system

    Projections of the hand field of the macaque ventral premotor area F5 to the brainstem and spinal cord

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    In the present study we first assessed that the hand motor field of the macaque ventral premotor area F5, involved in visuomotor control of hand actions, is connected to both the hand field of the primary motor cortex (M1) and the spinal cord. We then injected retroanterograde tracers in this field to completely illustrate its possible descending motor projections. In the brainstem the F5 hand motor field projects to the intermediate and deep layers of the superior colliculus (SC) and to sectors of the mesencephalic, pontine, and bulbar reticular formation, which are the sources of spinal projections. In the spinal cord, labeled terminals were virtually all confined to the C2-T1 segments, mostly contralaterally. At C6-T1 levels the labeling was weaker and mostly clustered laterally in the intermediate zone. At C2-C5 levels, labeled terminals were much denser and diffusely distributed over the mid-dorsal part of the intermediate zone where a propriospinal system that directly controls hand muscle motoneurons and mediates commands for the control of dexterous finger movements is located (Isa et al. [2007] Physiology 22:145-152). Thus, the F5 hand motor field has a weaker direct access and a stronger indirect access to spinal segments where hand muscle motoneurons are located, suggesting a role of this field in the generation and control of hand movements not only at the M1 level, but also at the spinal cord level. These projections may represent the neural substrate for the F5 hand motor field's role in the recovery of manual dexterity after M1 lesions. J. Comp. Neurol. 518:2570-2591, 2010

    Evaluation of vitamin B6 supplementation in Wilson’s disease patients treated with D-penicillamine

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    Introduction Wilson’s disease (WD) is a copper metabolism disorder characterised by a progressive accumulation of this metal mainly in the liver and the brain. Treatment is based on the removal of copper operated by the chelators, among which, D-penicillamine (DP) is prescribed as a first-line treatment in most situations. There is some evidence in linking the use of DP with a risk of vitamin B6; therefore, vitamin supplementation is sometimes recommended, although non-consensually. The objective of our study was to evaluate the level of vitamin B6 in WD patients treated with DP with and without associated supplementation.Methodology All WD patients followed at the National Reference Centre for WD in Lyon between January 2019 and December 2020 treated with DP for more than 1 year were included and separated in two groups according to vitamin B6 supplementation. The level of vitamin B6 was measured by the determination of pyridoxal phosphate (PLP).Results A total of 37 patients were included. Average age of 23.3±14.8 years, 15 patients with <18 years. Median duration of treatment was 51 (55.8) months. 15 patients were under vitamin B6 supplementation and 22 had interrupted it for more than 1 year. The median PLP level was significantly higher in the group with supplementation, 137.2 (86.7) nmol/L vs 64.9 (30.8) nmol/(p<0.01). No patient had a PLP level<35 nmol/L.Conclusion Long-term stable WD patients under DP treatment probably do not need vitamin B6 supplementation

    Multimodal architectonic subdivision of the rostral part (area F5) of the macaque ventral premotor cortex

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    We used a cyto-, myelo-, and chemoarchitectonic (distribution of SMI-32 and calbindin immunoreactivity) approach to assess whether the rostral histochemical area F5 of the ventral premotor cortex (PMv) comprises architectonically distinct areas, possibly corresponding to functionally different fields. Three areas were identified, occupying different parts of F5. One area, designated as "convexity" F5 (F5c), extends on the postarcuate convexity cortex adjacent to the inferior arcuate sulcus and is characterized, cytoarchitectonically, by a poorly laminated appearance, resulting from an overall cell population rather homogeneous in size and density. The other two areas, designated as "posterior" and "anterior" F5 (F5p and F5a, respectively), lie within the postarcuate bank at different anteroposterior levels. Major cytoarchitectonic features of F5p are a layer III relatively homogeneous in cell size and density, a cell-dense layer Va, and the presence of relatively large pyramids in layer Vb. Major cytoarchitectonic features of F5a are the presence of relatively large pyramids in lowest layer III and a prominent, homogenous layer V. Furthermore, our results showed that F5c and F5p border caudally with a caudal PMv area corresponding to histochemical area F4, providing additional evidence for a general subdivision of the macaque PMv into a caudal and a rostral part, corresponding to F4 and to the F5 complex, respectively. The present data, together with other functional and connectional data, suggest that the three rostral PMv areas F5p, F5a, and F5c correspond to distinct cortical entities, possibly involved in different aspects of motor control and cognitive motor functions
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