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Biomedical subjects

C Masson

Publications and source records attributed to C Masson.

At least 19 recordsLinked to original sources
PubMed1992

[Mental disorders in elderly hospitalized patients. Epidemiological study in an internal medicine department].

This epidemiological transversal study conducted on 100 patients older than 65 years hospitalized in the Internal Medicine department of a University hospital demonstrates the frequency of psychiatric pathology in these patients: dementia 19 percent; other psycho-organic disorders 17 percent; affective disorders 23 percent and other psychological disturbances 4 percent. Thus, 63 percent of this patient population had a mental disorder as defined by the DSM III criteria. These disorders are generally not or imperfectly identified by the internists in charge of these patients.

Aged↗
PubMed1992

[Dysautonomia and multi-systemic atrophy of the nervous system (Shy-Drager's syndrome)].

The clinical expressions of primary autonomic nervous system failure are more or less numerous, orthostatic hypotension being only one of them. Clinical analysis reveals 3 categories of manifestations: pure progressive dysautonomia, dysautonomia associated with Parkinson's disease, and dysautonomia associated with multiple system atrophy of the nervous system also known as Shy-Drager syndrome. Neuropathological studies show that lesions of the efferent autonomic nervous system (tractus intermediolateralis, sympathetic ganglia) are frequently associated with lesions of the central nervous system the role of which in dysautonomia is still imperfectly known. Lesions of the central nervous system may present as genuine Parkinson's disease with Lew bodies or as multiple systemic atrophy with its two best individualized aspects: striatonigral atrophy and olivopontocerebellar atrophy. These various neurological aspects have their counterpart in biochemical abnormalities, prognosis and response to treatment.

Aged↗
PubMed1992

Receptor-mediated endocytosis of the intrinsic factor-cobalamin complex in HT 29, a human colon carcinoma cell line.

A HT 29 cell line derived from human colonic carcinoma was shown to express the intrinsic factor receptor, with about 5000 binding sites per cell and an association constant of 20 x 10(9) 1/mol at pH 7.4 and 4 degrees C. The number of binding sites increased dramatically between 7 and 10 days of culture time. Endocytosis of the intrinsic factor-cobalamin-receptor complex was inhibited by two ways: at 4 degrees C and at 37 degrees C by incubating the cells with vinblastine, monensin and chloroquine. The plasma membrane receptor was cross-linked to [57Co]cobalamin-intrinsic factor and solubilized with Triton X-100. The cross-linked complex had a relative molecular mass of 330 kDa in native PAGE.

Chloroquine↗
PubMed1992

Sexual dimorphism of tarsal receptors and sensory equipment of the ovipositor in the European corn borer, Ostrinia nubilalis.

Sensilla on legs and ovipositor of the moth Ostrinia nubilalis were investigated by light and scanning electron microscopy. The ovipositor is composed of two papillae densely packed with medium length mechanoreceptor sensilla (MRb: 80-160 microns, n = 420-460). Long mechanoreceptor sensilla (MRa: 250-300 microns, n = 20-24) and contact chemoreceptors (CRa: 30-40 microns, n = 20-28) are evenly distributed at the periphery of these papillae. Legs support contact chemoreceptors (CRa), scattered among the scales. The pretarsus structure of each leg includes a single contact chemoreceptor (125 microns) inserted dorsally. The fifth tarsomere bears a ventral area without scales on which contact chemoreceptors are disposed in two parallel rows (CRb: 40-60 microns). A sexual dimorphism was found in the number and density of these sensilla (females: mean = 5.3, SD = 1.0; males: mean = 3.3, SD = 0.7), and in the size of the sensory field. The possible involvement of these sensory structures in oviposition site selection is discussed.

Animals↗
PubMed1992

The ultrastructure of the chromosome periphery in human cell lines. An in situ study using cryomethods in electron microscopy.

We studied the chromosome periphery in human HeLa and TG cells using cryomethods in electron microscopy. A contrasted layer of peripheral chromosomal material (PCM) was visible in cryo-ultrathin sections of mitotic cells. This PCM was composed of closely packed fibrils associated with granules. The PCM did not cover the entire chromosome surface but was found around most of the chromosomes and even between two chromatids. The organization of the PCM was not affected by colchicine treatment of mitotic cells. In cells prepared by quick-freezing, the PCM appeared to be a fibrous material at the chromosome periphery, and was also associated with granules that resembled inter-chromatin granules in size and shape. At higher magnification, direct contacts between the chromosomes and the fibrils of the PCM were observed. The cryotechniques used are known to preserve the native organization of cells. Therefore, the architecture of the perichromosomal region analysed presumably corresponds to that in vivo during mitosis. These observations show that in HeLa and TG cells, a particular structure present at the chromosome periphery in the form of PCM is persistent and ubiquitous. In addition, we showed by immunolabelling that the PCM is the specific site of accumulation of nucleolar antigens during mitosis. These two results, i.e. the identification of specific morphological structures and the compartmentation of proteins, indicate that this layer is a specific region of mitotic cells.

Cell Line↗
PubMed1992

Identification and characterization of a new set of nucleolar ribonucleoproteins which line the chromosomes during mitosis.

We investigated the perichromosomal architecture established during mitosis. Entry into mitosis brings about a dramatic reorganization of both nuclear and cytoplasmic structures in preparation for cell division. While the nuclear envelope breaks down, nuclear proteins are redistributed during chromosome condensation. Some of these proteins are found around the chromosomes, but little is known concerning their nature and function. Ten autoimmune sera were used to study the microenvironment of chromosomes and, in particular, the chromosome periphery. They were selected for their anti-nucleolar specificity and were found to recognize three nucleolar proteins that coat the chromosomes during mitosis. The distribution of these antigens was followed through the cell cycle by confocal laser scanning microscopy. The antigens dispersed very early during prophase and simultaneously with the chromosome condensation suggesting a correlation between these two processes. The antigens have apparent molecular weights of 53, 66, and 103 kDa on SDS-PAGE migration. Elution of the antibodies and immunopurification showed that they are RNA-associated proteins. The coimmunoprecipitating RNA moiety involved in these RNPs appeared to be U3, but the antigens are not related to the fibrillarin family. Therefore, small nucleolar RNPs follow the same distribution during mitosis as that described for small nuclear RNPs. Possible functions for these antigens are discussed.

Antibodies, Antinuclear↗
PubMed1992

[Left prerolandic infarction with initial epilepsy. Development of chronic hallucination psychosis].

A 34-year-old woman had three tonico-clonic seizures and aphasia revealing a left prerolandic infarct. Three weeks later, she began to develop psychiatric symptoms leading to the diagnosis of chronic hallucination psychosis. These symptoms were probably related to epilepsy and their cause was compatible with the diagnosis of interictal psychosis. It has been suggested that kindling of the mesolimbic system could account for psychosis in epilepsy. In our case, however, the sort time interval between the onset of epilepsy and the appearance of psychosis is not in favour of this mechanism.

Adult↗
PubMed1992

[Isolated vertigo disclosing infarction in the area of the posterior and inferior cerebellar arteries].

We report three cases of small cerebellar infarcts mimicking labyrinthine dysfunction. A sudden rotatory vertigo might be the only presenting symptom of a cerebellar infarct. In these cases, the clinical features may closely mimick an acute peripheral labyrinthine disorder. However, the absence of nystagmus or a direction changing nystagmus with different eye position and the normality of caloric responses may be suggestive of a cerebellar infarct. This syndrome may be explained by the involvement of the nodulus, part of the flocculo-nodular complex, that has primary vestibular connections. Cerebellar infarcts mimicking labyrinthine dysfunctions involved usually the cerebellar territory of the posterior inferior cerebellar artery (PICA). Infarcts may be limited to the territory of the medial branch of the PICA which supplies the nodulus.

Arteries↗
PubMed1991

[Bone density in 20 black African young adults of the Bantu race is identical to that in subjects of white race].

Bone mineral content (BMC in g) as well as bone mineral density (BMD in g/cm2) were measured by dual photon absorptiometry in 20 black africans and 20 white individuals of the same age and sex. The BMC of african males, as well as their body mass index (BMI), were significantly less than those of the whites. In contrast, neither BMD nor the ratio of BMC to BMI differed between the two groups. These results suggest that morphotype plays a greater role than the ethnic factor in the determination of bone mass in the young adult.

Adult↗
PubMed1991

Developmental study of afferented and deafferented bee antennal lobes.

The role of antennal sensory projections on the ontogeny of the bee antennal lobe was analyzed using both light and transmission electron microscopy. Normal and deafferented developing antennal lobes were examined. The results obtained show that (1) initiation of synaptogenesis in the antennal lobe is independent of the arrival of sensory inputs; (2) sensory inputs are necessary for setting up the glomerular antennal lobe organization; (3) regressive events, such as the reduction of synapse density, occur during the development of the antennal lobe; and (4) glomeruli formation appears as related to glia development.

Animals↗
PubMed1991

A novel 43-kDa glycoprotein is detected in the nucleus of mammalian cells by autoantibodies from dogs with autoimmune disorders.

We have characterized a new antibody specificity in a panel of sera from dogs developing systemic lupus erythematosus (SLE) or clinically related autoimmune disorders. This antibody stains in a speckled fashion the nucleus of cells of different mammalian origins. The target antigen is a basic (pI 9.2) nuclear polypeptide with an apparent molecular weight of 43 kDa (p43) which is detected in various mammalian cell nuclei. p43, as studied in HeLa cells, appears to be cell cycle-independent. It is released from nuclei by salts (0.5 M NaCl or 0.25 M ammonium sulfate). Upon subfractionation of nuclear components, p43 is found in the fraction containing HnRNPs and is recovered in immunoprecipitates obtained with 4F4 monoclonal antibody to HnRNP C proteins. Immunoelectron microscopy revealed that p43 is concentrated over the dense chromatin periphery and interchromatin granule clusters. Another important feature of p43 is its ability to specifically bind wheat germ agglutinin lectin but not concanavalin A nor Ulex europaeus I, supporting the notion that p43 is a glycoprotein bearing an N-acetyl-glucosamine moiety. Consistent with this result, a radio-active p43 band is specifically immunoprecipitated by canine anti-p43 autoantibodies from HeLa cells metabolically labeled with [14C]glucosamine. Finally, anti-p43 antibodies do not immunoprecipitate SnRNA, indicating that p43 has no apparent association with SnRNPs.

Animals↗
PubMed1991

Behaviour of nucleolar proteins in nuclei lacking ribosomal genes. A study by confocal laser scanning microscopy.

The behaviour of nucleolar proteins in cycling PtK1 cells and in micronuclei with or without NORs was investigated by immunofluorescence using antibodies from autoimmune sera and confocal laser scanning microscopy. These antibodies were shown by electron microscopy to recognize antigens confined to only one of the three basic nucleolar components: fibrillar centres (FC), dense fibrillar component (DFC) and granular component (GC). Serial optical sections allowed us to determine the three-dimensional organization of these components in the nucleolus of cycling cells. Furthermore, clear differences were found in the distribution of the various antigens in micronucleated cells. Three patterns could be observed: (1) the FC antigens were found mainly in the nucleoli, but also in varying amounts in the dots; (2) surprisingly, the DFC antigens were found to accumulate preferentially in the dots; (3) the GC-specific marker stained intensively the nucleoli as well the dots. The results are interpreted with regard to possible mechanisms for targeting nucleolar proteins to the site of nucleolar formation.

Biomarkers↗
PubMed1991

[Left pseudothalamic cortical syndrome and pain asymbolia].

We report a case of left pseudothalamic cortical syndrome associated with asymbolia for pain in a right-handed male patient. The responsible lesion, detected at both CT and MRI, was infarction of the superficial territory of the middle cerebral artery, restricted to the posterior insula, the superior aspect of T1, the parietal operculum and the supramarginal gyrus. The ascending parietal gyrus and the thalamus were spared. This case, together with data from the literature, suggest that the somatosensory area II was responsible for the pseudothalamic syndrome. This interpretation is concordant with the hypothesis that S II plays the principal role in passive somatosensory discrimination, whereas S I plays the principal role in active discrimination implying stimulus exploration. The location of lesions that were responsible for asymbolia for pain is discussed. This case and those reported by Berthier et al. (1988), provide arguments in favour of Geschwind's hypothesis which attributes asymbolia for pain to sensory-limbic disconnection due to damage of the insula.

Cerebral Cortex↗