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Biomedical subjects

R Habib

Publications and source records attributed to R Habib.

At least 181 records · Page 10Linked to original sources

[Amyloidosis].

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Amyloidosis↗

Novelty and familiarity activations in PET studies of memory encoding and retrieval.

Nine young right-handed men viewed colored pictures of people, scenes, and landscapes. Then, 24 hr later while undergoing PET scanning, they viewed previously studied (OLD) pictures in one type of scan, and previously not seen (NEW) pictures in another. The OLD-NEW subtraction of PET images indicates familiarity, and the NEW-OLD indicates novelty. Familiarity activations, signalling aspects of retrieval, were observed in the left and right frontal areas, and posterior regions bilaterally. Novelty activations were in the right limbic regions, and bilaterally in temporal and parietal regions, including area 37. These latter activations were located similarly to novelty activations in previous PET studies using visual words and auditory sentences, suggesting the existence of brain regions specializing in transmodal novelty assessment. The effects of novelty are seen both behaviorally and in replicable patterns of cortical and subcortical activation. We propose a 'novelty/encoding hypothesis': (1) novelty assessment represents an early stage of long-term memory encoding; (2) elaborate, meaning-based encoding processes operate on the incoming information to the extent of its novelty, and therefore (3) the probability of long-term storage of information varies directly with the novelty of the information.

Brain↗

[Membrano proliferative glomerulonephritis (author's transl)].

128 cases of Membrano proliferative glomerulonephritis have been divided in two groups, the first one (84 cases), with subendothelial deposits, the second one (44 cases) "with dense intramembranous deposits". Streptococcal infections more frequently precede the membranoproliferative glomerulonephritis with dense intramembranous deposits (20% and 11%). In this group there is a rapid onset and macroematuria is more frequent (36% and 18%). Nephrotic syndrome has the same frequency in the two groups (more than 80%). Because of the more frequent association "dense deposits" and crescents this group show a more frequent evolution toward renal failure (43% and 35%).

Antibody Formation↗

[Hereditary chorioretinal degeneration and nephronophthisis. The role of Senior-Löken syndrome].

Systematic clinical ocular examinations completed by electrophysiological studies were performed on fifty-five children with nephronophthisis. Twenty children, all under ten years of age, had tapetoretinal degeneration, either pure in fourteen cases (Senior-Löken syndrome), either associated with extra-oculorenal abnormalities in six cases (bones, liver, neurology). Twelve older children had a normal examination. Twenty-three children had a normal clinical examination, but non evolutive alterations of ERG.

Adolescent↗

Complement activation in acute glomerulonephritis in children.

Serial determinations of complement components (C1q, C4, C3, C5 and factor B) were performed in 32 children with acute glomerulonephritis. Low levels of C3 were found in 30 patients and low levels of C5 in 26. The findings of reduced C1q and/or C4 levels (25 patients) in the first days of the disease suggest activation of the classical pathway. Depressed Factor B levels were found rarely (4 patients). In all patients, the presence of a C3 splitting activity and/of a C3 nephritic factor-like activity was investigated. Both activities were demonstrated in 7 patients whereas in another patient, only C3 splitting activity was noted. A disappearance of both activities was observed in all patients. In 3 patients tested, the C3 nephritic factor-like activity was heat-labile and was therefore not related to true C3 nephritic factor. Both pathways are implicated in the early phases of the disease but continued C3 depression is probably through alternate pathway.

Acute Disease↗

Diffuse arterial calcified elastopathy--a new cause of renovascular hypertension in children.

Diffuse arterial calcified elastopathy was observed in 6 pediatric patients presenting with severe renovascular hypertension. Renal ultrasonography showed a characteristic pattern, the dotted corticomedullary junction, related to the increased echogenicity of the interlobar and/or arcuate arteries. Superficial temporal artery biopsy demonstrated the presence and the extension of the calcifying process involving the elastic layers of the muscular arteries. This clinicopathological syndrome may be heterogeneous from an etiological point of view: etiologic investigations led to the diagnosis of pseudoxanthoma elasticum in 2 patients; no etiologic cause could be found in the others.

Arterial Occlusive Diseases↗