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C Masson

Publications and source records attributed to C Masson.

At least 73 records · Page 4Linked to original sources
PubMed1999

Optimization of the production of a honeybee odorant-binding protein by Pichia pastoris.

A honeybee putative general odorant-binding protein ASP2 has been expressed in the methylotrophic yeast Pichia pastoris. It was secreted into the buffered minimal medium using either the alpha-factor preprosequence with and without the Glu-Ala-Glu-Ala spacer peptide of Saccharomyces cerevisiae or its native signal peptide. Whereas ASP2 secreted using the alpha-factor preprosequence with the spacer peptide showed N-terminal heterogeneity, the recombinant protein using the two other secretion peptides was correctly processed. Mass spectrometry showed that the protein secreted using the natural peptide sequence had a mass of 13,695.1 Da, in perfect agreement with the measured molecular mass of the native protein. These data showed a native-like processing and the three disulfide bridges formation confirmed by sulfhydryl titration analysis. After dialysis, the recombinant protein was purified by one-step anion-exchange chromatography in a highly pure form. The final expression yield after 7-day fermentation was approximately 150 mg/liter. To our knowledge, this is the first report of the use of a natural insect leader sequence for secretion with correct processing in P. pastoris. The overproduction of recombinant ASP2 should allow ligand binding and mutational analysis to understand the relationships between structure and biological function of the protein.

Amino Acid Sequence↗
PubMed1999

3-D organization of ribosomal transcription units after DRB inhibition of RNA polymerase II transcription.

In each bead of the nucleolar necklace, using adenosine analog DRB-treated PtK1 cells, we investigated the three components of rDNA transcription, i.e. the gene, transcription factor UBF and transcripts. In situ hybridization revealed the unraveling and 3-D dispersion of most of the rDNA coding sequences within the nucleus. The signals were small, of similar intensity and tandemly organized in the necklace. This observation is compatible with the fact that they might correspond to single gene units. Active transcription was visualized in these units, demonstrating that they were active functional units. Transcript labeling was not similar for each unit, contrary to UBF labeling. UBF and rRNA transcripts were only partially colocalized, as demonstrated by 3-D image analysis and quantification. As visualized by electron microscopy, the necklace was composed of a small fibrillar center partially surrounded by a dense fibrillar component. The 3-D arrangement of this individual unit in the necklace, investigated both by confocal and electron microscopy in the same cells, showed that the individual beads were linked by a dense fibrillar component. The reversibility of this organization after removal of DRB indicated that the beads in the necklace are certainly the elementary functional domain of the nucleolus. In addition, these results lead us to suggest that the organization of a functional domain, presumably corresponding to a single gene, can be studied by in situ approaches.

Animals↗
PubMed1999

Corticosteroid sparing effect of low dose methotrexate treatment in adult Still's disease.

OBJECTIVE: Adult Still's disease (ASD) is a rare chronic polyarthritis, usually treated with corticosteroid therapy. Because some patients become dependent on high dose prednisone or are refractory to that treatment, and because adverse events are frequent with corticosteroid, we evaluated the efficacy of low dose methotrexate (MTX) as a second-line drug. METHODS: We retrospectively studied 26 patients with ASD treated with low dose MTX because their disease was either resistant to or dependent on corticosteroids. RESULTS: The group included 13 women and 13 men, with a mean age of 32.6 years at onset of ASD. Mean disease duration at the beginning of MTX treatment was 59.9 mo (range 7 to 444). Evaluation took place at the maximum followup, which averaged 48.9 mo (range 8 to 136). The mean dose of MTX was 11.5+/-3.6 mg/week (range 7.5 to 17.5). Twenty-three patients responded to MTX; 18 had complete remission. No difference was seen between patients with or without extraarticular manifestations. Leukocyte and neutrophil counts and erythrocyte sedimentation rate were significantly reduced (p = 0.0001). Daily prednisone intake decreased by 69% (21.5 mg) (p = 0.0001). Eleven patients were able to stop taking corticosteroids. One patient with AA amyloidosis renal failure died of neutropenia: this was the only serious adverse event. CONCLUSION: MTX is an effective second-line treatment of ASD that does not respond to prednisone. It allows significant reduction of corticosteroid doses, which is beneficial to these patients, who have frequent and numerous corticosteroid related adverse events.

Adolescent↗
PubMed1998

[Hypersomnia].

Explore the source record for details and available documents.

Cataplexy↗
PubMed1998

Two novel monoclonal antibodies (1.9.E and 4.11.C) against olfactory bulb ensheathing glia.

We produced and characterized two monoclonal antibodies, termed 1.9.E and 4.11.C, that specifically recognize olfactory bulb ensheathing glia. Both antibodies were generated using the olfactory nerve layer (ONL) of newborn rat olfactory bulbs (P0, P1) as immunogens. The specificity of these antibodies was tested by immunofluorescence techniques on tissue sections and cultures of adult and neonatal rat olfactory bulbs, and by Western blot analysis. 1.9.E labeled the ONL and glomerular layer of the olfactory bulb (OB) of adult rats. In newborn rats, 1.9.E immunostained ensheathing cells from the ONL and peripheral olfactory fascicles. Furthermore, 1.9.E reacted with some processes of the radial glia in the periventricular germinal layer of the newborn rat. Although 4.11.C also specifically labeled ensheathing cells in the adult OB, it did not stain any cell type in the ONL of newborn rats. The lack of double labeling with either 1.9.E or 4.11.C and anti-olfactory marker protein (OMP) antibody, a specific marker for olfactory axons, indicated that none of the monoclonals recognized olfactory axons. Double immunostaining of adult OB cultures with 1.9.E or 4.11.C and anti-p75-nerve growth factor receptor revealed that both antibodies specifically recognized ensheathing glia in those cultures. Filaments were strongly labeled throughout the entire cytoplasm of ensheathing cells, suggesting that 1.9.E and 4.11.C immunoreacted with ensheathing glia cytoskeleton. 4.11.C stained a few Schwann cells in adult sciatic nerve sections. Moreover, 4.11.C immunostained cortical astrocyte cultures from newborn rats (P1). In Western blot analysis both antibodies recognized a major component, migrating with an apparent molecular weight of 60 kDa, from olfactory nerve and glomerular layer (ONGL) extracts of adult and neonatal rats. The pattern of immunoreactivity of 1.9.E and 4.11.C antibodies suggest that both antibodies are specific markers for olfactory ensheathing glia in the adult rat central nervous system (CNS).

Animals↗
PubMed1998

Time-frequency analysis of the noise produced by the closing of artificial heart valves: an in vitro study.

Clinical investigations showed that patients with an implanted mechanical heart valve are sometimes disturbed by the noise produced by the valve closing. The aim of this study was to investigate the noise generated by mechanical artificial heart valves with reference to the one produced by biological valves. This type of biological valve was used as a standard because it does not disturb the patient. We used an in vitro approach with a cardiovascular simulator. The noise signal was recorded simultaneously using a hydrophone and an accelerometer. During each cardiac cycle, because of the shortness of the signal (15-25 ms) and of the transient state, rapid frequency dynamics limited the usefulness of stationary analysis techniques for the first heart sound. Therefore, a time-frequency technique was much more convenient than a classic Fourier analysis. We used a discrete wavelet transform that pointed out the time fluctuation of each frequency component. Globally, mechanical valves produced a high sound level within the octave bandwidths centered on 64 Hz up to 512 Hz, while the amplitude of these components decreased rapidly for the biological valve.

Acceleration↗
PubMed1998

Magnetic resonance imaging of subacute myelopathy due to cobalamin deficiency.

A 77-year-old woman presented with rapidly ascending sensory ataxia. Magnetic resonance imaging (MRI) showed extensive involvement of the dorsal columns of the spinal cord. Hematological data were normal despite severe cobalamin deficiency. The contribution of magnetic resonance imaging in subacute degeneration of the spinal cord is discussed.

Journal Article↗
PubMed1998

Comparison of the angiotensin II receptor antagonist irbesartan with atenolol for treatment of hypertension.

In this multicenter, double-blind study, the antihypertensive efficacy and safety of irbesartan were compared with those of atenolol in patients with mild-to-moderate hypertension. Following a 4- to 5-week placebo lead-in period, 231 patients with seated diastolic blood pressure (SeDBP) 95-110 mmHg were randomized to irbesartan 75 mg or atenolol 50 mg once daily for 24 weeks. Doses were doubled at Week 6 for SeDBP > or = 90 mmHg. At Week 12, or anytime thereafter, doses were doubled for SeDBP > or = 90 mmHg if not done at Week 6, and hydrochlorothiazide and then nifedipine were added. Efficacy was determined by change from baseline in blood pressure and by therapeutic response rates. Safety was assessed by monitoring adverse events (AEs). Both treatments significantly lowered blood pressure from baseline. There were no significant differences between treatment groups with respect to blood pressure changes or therapeutic response. Atenolol significantly reduced seated heart rate compared with irbesartan at Week 12. The incidences of serious AEs and discontinuations due to AEs were approximately twice as high in the atenolol group compared with the irbesartan group. Thus, in comparison to atenolol, irbesartan < or = 150 mg provided at least equivalent blood pressure control while demonstrating an excellent safety and tolerability profile.

Adult↗
PubMed1998

Separation, characterization and sexual heterogeneity of multiple putative odorant-binding proteins in the honeybee Apis mellifera L. (Hymenoptera: Apidea).

According to precise molar mass determined by mass spectrometry and N-terminal sequence, some 25 odorant-binding-like proteins were characterized from the antennae and legs of worker and drone honeybees. Antennal specific proteins, composed of six different molecules, were classified into three subclasses according to N-terminal sequence homology. The major sexual difference was shown to lie in the relative abundance of these antennal specific proteins and in the occurrence of a drone-specific isoform. At least 19 other related proteins were found to occur in antennae and legs, forming another class showing homology with insect OBP. Genotype comparison of two honeybee races revealed a variability limited to this second class. Provided that these odorant-binding-like proteins are indeed able to bind odorants or pheromones, the question of whether their peculiar multiplicity contributes to the remarkable capacity of the honeybee to discriminate among a wide range of odor molecules is raised.

Amino Acid Sequence↗
PubMed1998

Different patterns of extension and recurrence in algodystrophy.

A true recurrence at exactly the same site is quite unusual in algodystrophy. Local or regional extension is possible. The bone scan is an easy way to demonstrate that the areas successively affected are not the same. An apparent local recurrence could in fact be a microscopic compression fracture of trabecular bone or cortical fractures or part of a factitious disorder.

Adult↗
PubMed1998

Further vascular, bone and autonomic investigations in algodystrophy.

Direct clinical observation is the most common means of diagnosing algodystrophy. Further investigations may be helpful to rule out other pathological conditions, such as occult or stress fractures or avascular osteonecrosis and to obtain a better understanding of algodystrophy. Transient vascular hyperpermeability in the affected part is well demonstrated by the clinical findings, the MRI signs, and the three-bone scan features. 99m Technectium EHDP bone scan provides an evaluation of the vascular abnormalities and of the osteoblastic activity. Dermal microcirculation and its reactions to sympathetic stimuli are investigated by laser doppler fluximetry and videophotometric capillaroscopy. Perhaps the sweat test does unveil what might be specific about algodystrophy. The amount of bone loss in algodystrophy in a few weeks or months is what might be expected over 10 years during the natural history of uncomplicated osteoporosis. An initial fracture is undoubtedly an initiating event in the appearance of algodystrophy, but patients suffering from algodystrophy may still have significant osteoporosis for a long period and hence be at risk for fracture. Densitometry could be an aid to the diagnosis and probably to monitoring treatment as well. The local colonization of fibroblasts following the transient stage of hyperpermeability must be kept in mind to explain the results of joint, bone, muscles or neurological investigations in late algodystrophy.

Absorptiometry, Photon↗
PubMed1998

A randomized, double blind, placebo controlled multicenter trial of murine anti-CD4 monoclonal antibody therapy in rheumatoid arthritis.

OBJECTIVE: To assess safety and efficacy of a murine anti-CD4 monoclonal antibody (Mab) in a population of patients with rheumatoid arthritis (RA) compared to treatment with placebo. METHODS: Fifty-eight patients with defined RA were included in this placebo controlled, randomized, double blind, multicenter study. Of the 48 women and 10 men (mean age 54.5 years), 25 were functional class II and 31 were class III, with 9 years' disease duration; the mean of previous disease modifying antirheumatic drugs was 4; 49 were taking steroids (mean dosage 11 mg/day of prednisone). Eighty percent were rheumatoid factor positive. All were in an active state of the disease with: pain > 4 (mean at inclusion 6.6), tender joints > 4 (mean 12), swollen joint count > 3 (mean 9), morning stiffness > 45 min (mean 185), erythrocyte sedimentation rate > 30 mm (mean 59) or C-reactive protein (CRP) > 30 mg/l (mean 63). Treatment was randomized between murine anti-CD4 Mab (B-F5, Diaclone, 20 mg/day) or placebo intravenously for 10 consecutive days. Efficacy was assessed with a composite index (Paulus), with evaluation of number of patients with 20 or 50% improvement in each group. Changes in measures of single clinical or biological variables were also evaluated. RESULTS: The 2 groups were comparable at inclusion. Treatment was well tolerated. Mild side effects (chills, fever, rash) were seen in both groups. Percentage of patients with global 20 or 50% response did not differ between placebo and Mab groups at Day 10 or at Day 30. Evaluation of single variables showed reduced CRP, swollen joint count, and Ritchie index in some B-F5 patients at Day 10, although in the B-F5 group as a whole only CRP was significant. CONCLUSION: No significant improvement in RA after murine anti-CD4 Mab was observed.

Adult↗
PubMed1997

Biochemical characterization, molecular cloning and localization of a putative odorant-binding protein in the honey bee Apis mellifera L. (Hymenoptera : Apidea).

A honey bee antennal water-soluble protein, APS2, was purified and characterized as the first Hymenoptera putative odorant-binding protein. Comparison of its measured Mr (13695.2+/-1.6) to that of the corresponding cDNA clone shows it does not undergo any post-translational modification other than a 19-residue signal peptide cleavage and formation of three disulfide bridges. These biochemical features are close to those of Lepidoptera odorant-binding proteins. In situ hybridization experiments demonstrated its specific expression in olfactory areas. Based on its higher expression in the worker than in the drone, ASP2 might be more involved in general odorant than in sex pheromone detection.

Amino Acid Sequence↗