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Biomedical subjects

C Masson

Publications and source records attributed to C Masson.

At least 145 records · Page 8Linked to original sources
PubMed1993

Localization of the RNA polymerase I transcription factor hUBF during the cell cycle.

Autoantibodies directed against nucleoli that recognized a doublet of 97-94 kDa in HeLa nuclear protein extracts were identified. The two polypeptides bound equal amounts of antibody, and each was recognized by antibodies affinity purified using the other polypeptide. These antigens were localized in the secondary constriction of PtK1 cells, i.e. the nucleolar organizer regions (NORs) where ribosomal genes accumulate. They were observed in human cells in the same sites as the NOR-silver-stained proteins. The molecular mass of the antigens, their characteristics in Western blotting and their localization in nucleoli and NORs during mitosis are consistent with them being RNA polymerase I transcriptional factor, UBF. This identification was confirmed on Western blotted proteins by their identical labelling patterns, using these autoantibodies and an anti-mUBF antibody that had been previously described. We obtained definitive evidence that these autoantibodies recognize UBF by the strong positive labelling of purified hUBF (1 to 4 ng). During interphase, these autoantibodies directed against UBF labelled in a folded filament pattern as small beads that may correspond to individual transcriptional units. In electron microscopy, the antibodies were observed in the dense fibrillar component (DFC) of the nucleoli and at the periphery of the fibrillar centers (FCs). At the end of G2 phase, transcription inactivation was concomitant with the gathering of UBF at mitotic NORs. UBF was not equally distributed between NORs in human cells: some NORs scored negative (2 to 4) and the intensity of labelling of positive NORs (6 to 8) differed. In confocal microscopy, 3-dimensional analysis of mitosis indicated that UBF remained associated with NORs during all mitotic stages and that there was equal partition of UBF between the daughter cells. The relationship between proteins associated with the NORs and ribosomal gene transcription is discussed.

Antibodies, Antinuclear↗
PubMed1993

[Dissociated preservation of written expression in aphasia with recurrent utterances].

In a female patient, aphasia with recurrent utterances resulted from a double lesion of the left hemisphere, located in the base of the third frontal gyrus and the upper temporal gyri. Predominant in the fluent oral expression was a repeated neologism of which the patient was unaware. The written expression, efficient for lexical entities, was devoid of syntax and had the features of phonological agraphia. Both orally and in written words comprehension was satisfactory but syntactic comprehension was deficient. The stereotyped verbal behaviour could be due to dysfunction of the phonemic programmer. Rupture of the audi-phonatory loop, confirmed by degradation of the verbal working, memory, made this dysfunction worse and accounted for the anosognosia. The participation of the right hemisphere and of the preserved left hemispheric structures in the persistence of various language activities are discussed.

Aphasia↗
PubMed1993

[Migratory algodystrophy of the lower limbs involving the foot and complicated by two fatigue fractures. An histological bone study].

A 62 year old male developed transient osteoporosis algodystrophy successively in several sites of the lower limbs (8 episodes of involvement of one or two sites over an 8-year period) three years after surgery for a chromophobic pituitary adenoma. Two stress fractures developed, during the sixth and seventh years, respectively, in bones previously affected by osteoporosis. A biopsy specimen from the distal tibia showed thin bone trabeculae and reduced cellular activity. The only etiologic factor was the patient's psychological profile characterized by anxiety and introversion.

Bone and Bones↗
PubMed1993

[Pyomyositis. Apropos of 5 cases].

Four patients meeting the "classical" criteria for spontaneous pyomyositis are reported. No local cause was found. Risk factors included diabetes mellitus (2 patients), hemopathy (one patient), and alcohol abuse (one patient). Causative organisms (Staphylococcus aureus in 3 cases and Salmonella sp in one case) were recovered from blood cultures, an unusual occurrence. CT scan studies ensured the diagnosis in every case. An additional case of pyomyositis due to Staphylococcus aureus illustrates the difficulties in the definition of disease. This patient, whose muscle lesions were remarkably well visualized by MRI with injection of gadolinium, developed infection of the sacro-iliac joint adjacent to the muscular focus of infection. This patient may have had either "primary" pyomyositis with spread to the adjacent joint or "secondary" pyomyositis caused by the joint infection which was recognized only later. Advances in medical imaging techniques suggest that the nosology of pyomyositis should be broadened using this terminology. This would underscore the unique characteristics of "classical", "primary" pyomyositis and emphasize imaging, diagnostic and therapeutic facets of the disease which are shared by both entities.

Adult↗
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↗