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Biomedical subjects

C Masson

Publications and source records attributed to C Masson.

At least 127 records · Page 7Linked to original sources
PubMed1994

[Ischemic spinal cord disorders].

Infarcts in the territory of the anterior spinal artery usually are located in the Adamkiewicz artery. Onset is either sudden or progressive with clinical signs of deficit and spinal pain of short duration. The extent and distribution of the deficit depends on the extension and the level of the spinal lesions. A perfect knowledge of the spinal cord vascularization is required to discern the complex and variable clinical expression. Unlike cerebral vascular events, emboli or cardiac origin are rarely involved in spinal cord events. Aortic pathology, including surgery of the aorta, is however of major importance in ischaemic spinal cord syndromes. Several reports have shown that atheroma causing spinal cord ischaemia are not located in the perispinal arterial network but lie on the aorta and its spinal branches. Dissection of the aorta is found responsible in 2 to 8% of the cases. Isthma stenosis can also give spinal cord signs and syphylitic arteritis is exceptionally encountered. Other rare causes are gas emboli and fibrocalcium emboli.

Humans↗
PubMed1994

[POEMS syndrome].

POEMS syndrome has been defined as an association of plasma cell dyscrasia with polyneuropathy, organomegaly, endocrinopathy, M protein and skin changes. Although certain authors do not distinguish this syndrome from osteosclerosing myeloma, syndromes comparable to POEMS have been observed without bone lesions. Others have described the clinical features involved under the terms of Crow-Fukase's syndrome, PEP syndrome (pigmentation, oedema, plasma cell dyscrasia, or Takatsuki's syndrome. Seen in men twice as often as in women, usually between the ages of 40-50 years, all five clinical features are not always present or may be accompanied by other signs. The first sign of the peripheral polyneuropathy is usually sensorial impairment followed by distal then proximal motor deficit. The deficit is usually severe and 50% of the patients become unable to walk. Cranial nerves are rarely involved. Liver, spleen and lymph node enlargement are observed. The most frequent signs of an endocrinopathy are gynaecomastia, atrophy of the testicules, impotence and amenorrhoea. Testosterone levels are low and oestrogen levels are increased in men together with luteinizing hormone, follicle stimulating hormone and prolactin. Hypothyroidism is frequent and diabetes mellitus is observed in 50% of the patients. Protein M is a monoclonal immunoglobulin (IgG or IgA), almost always with a light lambda chain. Skin changes include hyperpigmentation, hypertrichosis, hyperhidrosis, thickening of the skin suggestive of sclerodermia and papillary angiomas. Other signs, especially peripheral oedema often occur early in the disease course and may precede the peripheral neuropathy. POEMS syndrome is often associated with a myeloma (up to 50% of the cases in certain series). Although immunoglobulin deposit on myelin sheaths, anti-endocrine antibodies and receptors of lambda chains have been proposed as playing a role, no mechanism of pathogenesis has been determined. The natural history of the disease leads to a severe polyneuropathy. The patients become totally bedridden and death results from complications of decubitus rather from the direct effect of the underlying dyscrasia. When bone lesions are minor, radiotherapy or surgery can improve the neuropathy and resection of a solitary plasmocytoma can lead to total remission. Chemotherapy or corticosteroids may improve the polyneuropathy in certain cases. Plasma exchange has not been successful.

Adrenal Cortex Hormones↗
PubMed1994

How neurons may compute: the case of insect sexual pheromone discrimination.

Recognition of pheromone scent by male insects probably depends on analyzing the blend's composition in terms of relative concentrations of major and minor molecular components. Based on anatomical, physiological and behavioral data concerning certain moth species and the cockroach, we propose a simple, biologically plausible neural circuit which is able to perform this task reliably. The model employs oscillations as a detecting device. This principle is easily generalized to other systems. As a computational device, ratio detection may find applications in a variety of biological situations, e.g. in the olfactory system of all animals.

Animals↗
PubMed1994

Monitoring the activity of glucose oxidase during the cultivation of Aspergillus niger using novel amperometric sensor with 1, 1'-dimethylferricinium as a mediator.

1, 1'-dimethylferricinium (DMF+), a deep blue, and stable mediator, was prepared from a water-soluble 1, 1'-dimethylferrocene(DMF):2-hydroxypropyl- beta-cyclodextrin complex via enzymatic oxidation using immobilised bilirubin oxidase. This mediator was superior to other soluble ferrocenes, notably carboxyferrocene, in terms of both solubility (110 mM vs 0.5 mM) and oxidation potential (150 mV vs 300 mV against Ag/AgCl). Although the cyclic voltammogram of DMF+ was electrochemically equivalent to DMF, the use of the former resulted in a significantly lower background current (< 10 nA vs 30 nA). Because of its higher solubility, concentrated stock solutions of DMF+ can be prepared and supplied to the electrode. This is of particular importance when the signal is severely limited by the rate at which the working electrode can oxidase DMF to DMF+. A linear response of current versus units of glucose oxidase (GOD) was obtained up to 0.5 unit/ml. The detection limit was estimated to be 0.03 unit/ml and the response time was 2.5 min or less. The amperometric system was used successfully to follow the GOD activity during the growth of Aspergillus niger a well-known GOD producer. The results obtained correlated well with a standard absorbance-based assay using dichlorophenol-indophenol (DCPIP). The KM of GOD for the glucose in the lysate was measured as 38 mM. A reduced response and higher KM (48 mM) of the cell homogenate, compared to the lysate, illustrated the requirement for the DMF+ and glucose to diffuse across the cell membrane to interact with GOD in whole cells.

Aspergillus niger↗
PubMed1994

Fate of specific nucleolar perichromosomal proteins during mitosis: cellular distribution and association with U3 snoRNA.

In mammalian cells, the nucleoli disintegrate during mitosis and some nucleolar proteins disperse at the periphery of all chromosomes forming a novel class of chromosomal passenger proteins. The nucleolar components which participate in the formation of this perichromosomal layer have been investigated to elucidate the role of these perichromosomal proteins in the assembly and disassembly of the nucleoli. i) Electron microscopy immunolabelling reveals that these proteins are predominantly located in the granular component of the nucleoli during interphase. ii) Immunoprecipitation data suggest that they are distributed at the chromosome periphery in association with U3 small nucleolar RNA (snoRNA). In addition, the distribution of U3 snoRNA visualized by in situ hybridization, is similar to that observed for the perichromosomal proteins. iii) In cells which possess a nucleolar remnant during mitosis, U3 snoRNA and perichromosomal proteins were found both in the perichromosomal layer and in the nucleolar remnant. iv) Some of these proteins are conserved from yeast to man such as fibrillarin and a protein of 52 kDa. v) The location of these proteins observed in yeast by confocal microscopy shows that they are not dispersed during mitosis. Their partition between the two daughter cells is performed by scission of nucleolar structures forming a rod during the budding process. Therefore RNP complexes related to the processing steps of ribosome biogenesis in mammalian cells quit the nucleolus in late G2 and associate with the chromosome periphery until late telophase. They associate in the perichromosomal layer in human and PtK1 cells and both in the perichromosomal layer and the nucleolar remnant in CHO cells.

Animals↗
PubMed1994

Honeybees have putative olfactory receptor proteins similar to those of vertebrates.

Using nested-PCR amplification of honeybee cDNA with degenerate primers derived from mammalian sequences, we have cloned four DNA fragments from putative odour receptor genes. This conclusion is based on high amino acid sequence similarity with published sequences from vertebrates and hydrophilicity profiles in agreement with including these genes in the super family of seven transmembrane domain receptor genes. These results are discussed in the context of the evolution of the olfactory receptor genes.

Amino Acid Sequence↗
PubMed1994

[Apraxia and autotopoagnosia without aphasia or agraphia with compulsive language activity in right hemispheric lesion].

A 75 year-old woman was admitted with a left hemiplegia resulting from an infarct in the right middle artery's territory. Her manual preference was ambiguous from early childhood. She presented with severe bilateral apraxia, autotopoagnosia, finger agnosia, and left spatial neglect. There was, however, no aphasia nor agraphia. When the patient attempted to perform gestures on order, she compulsively produced oral or written language. In this very unusual case, dominance for gesture and dominance for language were strictly independent, each ensured by one hemisphere. The patient's performances in gestual activities, especially dissociation between automatic and voluntary movements, and compulsive linguistic productions, are discussed in relation to this functional lateralization. We suggest that the propositional nature of the responses required in test conditions could activate either voluntary language in the left cerebral hemisphere, or voluntary gestures in the right. A competition between the two hemispheres could explain the patient's linguistic apraxic or behavior in response to orders. Autotopoagnosia, an uncommon symptom, could interfere with apraxia, but is not directly responsible.

Aged↗
PubMed1994

[Hippocampothalamic infarction. A limited form of infarction in the posterior cerebral artery area].

Infarction of the hippocampus and the right ventroposterolateral thalamus was observed. Angiography revealed a posterior cerebral artery occluded near its origin, immediately upstream from the posterior communicating artery. The infarction was limited to the areas irrigated by the branches originating in the proximal part of the artery. More distal branches for the calcarine scissure and the temporooccipital gyruses were not involved.

Adult↗
PubMed1993

Increased frequency of NGF in sera of rheumatoid arthritis and systemic lupus erythematosus patients.

Nerve growth factor (NGF) levels were measured by a two-site enzyme-linked immunosorbent assay (ELISA) in sera of patients with three autoimmune diseases, rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and thyroiditis. Serum NGF levels were variable (15 pg ml(-1)-1.6 ng ml-1) but not significantly different among these groups compared with control subjects. However the frequency of detectable circulating NGF was significantly higher in RA and SLE patients but not in thyroiditis patients compared with controls. The present data provides evidence for NGF involvement in two autoimmune rheumatic diseases and suggests a possible differential role of NGF as immunomodulatory agent in systemic versus certain organ-specific autoimmune diseases.

Adolescent↗
PubMed1993

Induction of recombinant human gamma-glutamyl transferase by sodium butyrate in transfected V79 and CHO Chinese hamster cells.

Sodium butyrate was used to enhance biosynthesis rates of recombinant human gamma-glutamyl transferase (GGT) expressed under the control of the SV40 or the cytomegalovirus immediate early promoter, respectively, in transfected V79 and CHO Chinese hamster cell lines. Maximal induction of GGT specific activity in butyrate-treated cells ranged from 3 to 5-fold and resulted from a strong increase in the GGT mRNA ratio. We also observed that maximal transcription level in V79 cells occurred within 12 hr of treatment, whilst the cell proliferation was transiently arrested. Despite its processing requirements, induced GGT exhibited unchanged catalytic and physico-chemical features relative to human serum or hepatoma enzyme, thus appearing as an excellent model for further studies on human GGT.

Animals↗
PubMed1993

[Role of the titration of anti-neutrophil cytoplasmic antibodies in therapeutic follow-up of patients with systemic vasculitis].

We studied clinical and biological data of 18 patients presenting ANCA associated diseases for 16 months at least. Five relapses were preceded by ANCA elevation, 1 relapse was not. Four transient elevations were noted without any clinical event. We think ANCA level elevation by itself is not enough for deciding therapy intensification, clinical data are necessary for doing so.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1993

Non specific interactions in anti-agent IgE-RIA to anesthetic agents.

The sensitivity of usual IgE-RIA for detecting seric anti-neuromuscular blocking drug (NMBD) IgE antibodies is low. Our group and other authors have proposed quaternary ammonium compounds other than NMBD for the preparation of sepharose solid drug phase. These compounds cannot be cyclohexenyl derivatives in order to prevent hydrophobic interactions with seric hydrophobic IgE. Allergic reactions against cyclohexenyl derivatives such as propofol could be linked to a non-specific hydrophobic binding of the drug to hydrophobic seric IgE. Such hydrophobic IgE are seen in 30% of atopic subjects, in 41% of patients with drug allergy and in 100% of those allergic to propofol. The latter had also anti-quaternary ammonium IgE in 5 out of the 8 cases studied. These NMBD antibodies could bind to the quaternary-ammonium ion of the lecithins from Diprivan micelles.

Antibodies, Anti-Idiotypic↗
PubMed1993

Cranial pachymeningitis of unknown origin: a study of seven cases.

We report seven patients with cranial pachymeningitis of unknown origin in whom the main clinical features were headaches, ataxia, and cranial nerve palsies. CSF showed inflammatory changes. CT and MRI showed thickening of the falx and of the tentorium. The clinical course was chronic. Four patients improved with prednisolone but became steroid-dependent: in two cases, radiotherapy had no lasting improvement and in one, azathioprine permitted a reduction of the corticosteroids. Five patients had biopsy of the tentorium cerebelli or of the temporal dura mater. In two cases, autopsy revealed extensive pachymeningitis without parenchymal changes. In all instances, microscopic examination of the dura mater showed a cellular infiltrate of polymorphic cells; there were no epithelioid granulomas. Review of the literature discloses seven similar cases. We discuss the relationship of these lesions with inflammatory meningeal masses, the focal pachymeningitis of the Tolosa-Hunt syndrome, and multifocal fibrosis.

Adult↗