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C Masson

Publications and source records attributed to C Masson.

At least 253 records · Page 14Linked to original sources
PubMedDate not supplied

Sterically stabilized BGTC-based lipoplexes: structural features and gene transfection into the mouse airways in vivo.

BACKGROUND: Colloidal stability of lipid/DNA aggregates is a major requirement for cationic lipid-mediated transfection which is particularly difficult to fulfil at the high DNA concentrations used for in vivo gene delivery. Thus, we have investigated the potential of poly(ethyleneglycol) (PEG) conjugates for steric stabilization of lipoplexes formed by bis(guanidinium)-tren-cholesterol/dioleoyl phosphatidylethanolamine (BGTC/DOPE) liposomes, a class of cationic liposomes we have developed over the past few years. METHODS AND RESULTS: We demonstrate that adequate lipophilic PEG derivatives can stabilize BGTC/DOPE lipoplexes formed at high DNA concentration. We also report the results of cryotransmission electron microscopy studies indicating that PEG-stabilized lipoplexes form DNA-coated structures which assemble into clusters exhibiting various complex morphologies. Finally, we report data from in vivo transfection experiments suggesting that PEG-mediated colloidal stabilization of concentrated lipoplex solutions may allow enhanced transfection of the mouse airways via intranasal administration. CONCLUSION: Our results represent an important step towards the design of multimodular BGTC-based systems for improved in vivo gene transfection.

Animals↗
PubMedDate not supplied

Molecular parameters involved in bee-plant relationships: a biological and chemical approach.

Honeybee-plant relationships are based on a conditioning process in which olfactory (plant aroma) and gustatory cues (mainly nectars) are closely linked, leading to a selective foraging behaviour. Among crops dependent upon entomophilous cross-pollination, the sunflower has recently undergone extensive expansion due to hybrid variety selection. Sunflower hybrid seed production is strictly dependent upon pollinating insects, mainly the honeybees, but foragers may have preferences among the parental lines, leading to a lack of pollen carriage and consequently to a decrease of hybrid seed yield. In order to define the role of plant chemicals (aromas, nectars) involved in the pollination process, we set up a study combining behavioural and chemical assays. It appears that even though volatile chemical blends are much more complex compared to glucidic blends, for both kinds of cues only a 'limited chemical pattern' is responsible for foragers' choices. Therefore, it is henceforth possible to take these molecular criteria into account for plant improvement.

Animals↗
PubMedDate not supplied

[Iatrogenic neuropathies].

During the last few years the list of drugs capable of inducing a iatrogenic neuropathy has been considerably lengthened. Drug toxicity to peripheral nerves may be discovered at the experimental stage, but it is usually recognized after the drug has been launched on the market, hence the importance of pharmacovigilance. The responsibility of a drug for the occurrence of neuropathy may be difficult to prove, particularly when the drug is used in the treatment of a disease which, by itself, may be responsible for a lesion of the peripheral nervous system. Iatrogenic neuropathies are usually axonal, but some drugs produce a primary disorder in the myelin-Schwann cell couple. Schwann cell diseases may be induced by drugs, such as perhexiline maleate, amiodarone or chloroquine, which inhibit lysosomal enzyme activity. In such cases inclusions representing fat-loaded lysosomes can be detected in various tissues, and particularly in Schwann cells. In certain patients, notably those treated with gold salts, an immune mechanism might be responsible for neuropathy. Most drug-induced neuropathies are due to a primary lesion of the neuron which is more often an axonopathy than a neuronopathy. It is usually a retrograde distal axonopathy the occurrence of which is attributed to a disorder of the fast retrograde axonal flow. In a few cases, the finding of a biochemical mechanism perturbing the axonal flow may help in preventing the occurrence of a iatrogenic neuropathy.

Amiodarone↗
PubMedDate not supplied

Identification and developmental profiles of hexamerins in antenna and hemolymph of the honeybee, Apis mellifera.

Four distinct hexamerin subunits (referred to as "hexamerins" in the following text) have been identified in the developing honeybee, Apis mellifera, by N-terminal protein sequencing. Hexamerins are abundant in the hemolymph of late larval and early pupal stages, and gradually decline during metamorphosis and adult development. Three hexamerins in the 70 kDa range have been found (Hex70a, Hex70b, Hex70c). In worker and drone, Hex70a is the only hexamerin present in large amount in later adult stages. Hex70b and c exhibit a similar developmental profile, disappearing in the drone just before adult emergence, and in the worker just after. Hex70b or Hex70c are still detectable in the adult queen. Hex80/110 likely exist in at least 3 different subunits, 1 of 110 kDa, and 2 of around 80 kDa, which all share a common N-terminus. They disappear during metamorphosis earlier than Hex70b and c. All these hexamerins have been found also in the antenna, suggesting their utilization in building up of antennal cuticle structures.

Amino Acid Sequence↗
PubMedDate not supplied

Cerebral venous infarction following thrombosis of the draining vein of a venous angioma (developmental abnormality).

We report two cases of cerebral venous angioma presenting as venous infarction, one in the left parietal lobe, the other in the left frontal lobe. Cerebral imaging demonstrated thrombotic occlusion of the draining vein of the venous angioma associated in the latter case with thrombosis of the anterior part of the superior longitudinal sinus. Both patients were free of coagulopathy. They were treated with anticoagulant therapy. One completely recovered, while the other was left with slight residual disability. Thrombosis of the draining vein has been reported in only 6 previous cases, of whom only 2 received anticoagulant therapy. Discovery of a venous angioma in the diagnostic workup of a patient with recent neurological disorders should raise the question of a possible occlusion of the draining vein and lead to an appropriate therapy.

Adult↗
PubMedDate not supplied

[Toxoplasmosis serodiagnosis: comparison of Access Toxo IgM II assay compared to Axsym Toxo IgM and Vidas Toxo IgM assays].

The Access Toxo IgM II test (Beckman Coulter Inc) was evaluated on 1,190 samples from toxoplasmosis serology requests, documented seroconversions, umbilical cord blood or venous blood from healthy newborn, and from newborns with congenital toxoplasmosis. Results were compared to those obtained with Vidas (bioMérieux) and Axsym (Abbott) assays, with Isaga as confirmatory technique. Results obtained with the Access test well correlate those with the Vidas (98.3%) and the Axsym (97.6%) assays. Less "bordeline" results are also observed with the Access test (0.22% versus 0.56% and 1.24% with Vidas and Axsym assays respectively). Results obtained from seroconverted patients prove that the Access assay is more sensitive than Vidas and Axsym assays, with respectively 2 and 4 samples detected earlier for 28 cases studied (recently seroconverted patients). Results obtained using prospective samples and with sequential sera obtained from patients with seroconversion clearly demonstrate that Access Toxo IgM II assay is perfectly adapted to toxoplasmosis diagnosis.

Adult↗
PubMedDate not supplied

[Evaluation of a new fluorometric immunoassay for the detection of anti-cyclic citrullinated peptides autoantibodies in rheumatoid arthritis].

Anti-cyclic citrullinated antibodies occurrence is a recent serological marker for rheumatoid arthritis. The aim of our study was to evaluate the measurement of these antibodies by a new fluorescent-enzyme immunoassay, called EliA CCP, fully automated onto UniCAP 100. This evaluation reveals correct and shows a within run imprecision of 4.6 to 10.5 % and a between-assay imprecision of 9,5 %. The comparison with an Elisa method (Euroimmun) shows a good correlation of anti-CCP concentrations without any major discrepancy.

Adult↗
PubMedDate not supplied

[Evans' syndrome caused by D-penicillamine in rheumatoid arthritis. Value of the corticoids-danazol combination].

The authors report the development of thrombocytopenia purpura in one patient with seropositive and erosive rheumatoid arthritis treated successfully for 11 months with D-penicillamine. Anti-platelet-bound antibodies were present, but also: anti-erythrocyte antibodies with hemolytic anemia (then defining Evans's syndrome): higher level of antinuclear antibodies; intermittent neutropenia. The responsibility of D-penicillamine is discussed, but thrombocytopenia purpura evolved for itself. Glucocorticoids alone, intravenous immunoglobulin, vincristine did not induced remission, which at least occurred under the association danazol-glucocorticoids, without toxicity, especially on the liver function.

Anemia, Hemolytic, Autoimmune↗
PubMedDate not supplied

[Beta-blockers and migraine. Efficacy of time-release propranolol versus placebo].

The efficacy and safety of long-acting propranolol (LA.P) 160 mg once-daily in the prophylactic treatment of migraine were tested against placebo in a multicentric, double-blind, randomized study comparing the two groups in a parallel manner over a treatment period of 12 weeks, and following a 4 week-placebo run-in period. Fifty-five out of the 74 patients who entered the trial included at the end of the run-in period. Forty-one patients completed the study. Out of the 14 patients who withdrew from the study, none discontinued because of side-effects. The statistical analysis was done according to the "intention to treat" principle. LA.P was significantly more efficient than placebo in reducing the frequency of migraine attacks (p = 0.01 by variance analysis). LA.P reduced the average number of monthly crises by 48% on day 84. There was a slight but significant reduction of the systolic blood pressure and heart rate in the erect position. There was no significant difference between LA.P and placebo regarding either the number of complaints or the number of side-effects elicited out of an 17 item questionnaire. None of the observed side effects led to a withdrawal of treatment.

Adult↗
PubMedDate not supplied

Hypertrophic cranial pachymeningitis: assessment with CT and MR imaging.

Three patients with diffuse idiopathic cranial pachymeningitis with predominant involvement of the tentorium and falx are reported. Progressively increasing headaches were the usual symptoms, along with ataxia and various cranial nerve palsies. CT in all cases and MR imaging in two cases detected isolated thickened dura mater. In one case, MR depicted dural involvement as a very large, hypointense area with fine hyperintense edges on T2-weighted images. Microscopic examination of thickened dura revealed extensive fibrotic tissue with a chronic inflammatory infiltrate containing lymphocytes, plasma cells, and scattered eosinophils; these findings closely paralleled the MR features. Only four cases with similar pathologies have been described, all before the advent of CT and MR. We discuss the different causes of thickened dura mater as well as the significance of the fact that dural thickening can be responsible for occlusion of the dural sinuses. Cranial pachymeningitis is a rarely reported disease that can resemble other disorders associated with tentorial thickening; CT and MR can help differentiate it from these other disorders.

Adult↗