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P Bertin

Publications and source records attributed to P Bertin.

At least 73 records · Page 4Linked to original sources
PubMed1996

Analysis of the complementary determining region III of the immunoglobulin heavy chain locus in acute lymphoblastic leukemia in Chilean children.

We have analyzed the sequence of 40 VDJ rearrangements of the immunoglobulin heavy chain gene locus on 32 unselected children from Chile with precursor B cell ALL at diagnosis. Rearrangements were derived by PCR with VH gene family-specific primers and sequenced directly. The number of VDJ rearrangements, and the pattern of VH, DH and JH gene usage was identical to the one reported by groups from developed countries. CDR3 regions represented an unbiased repertoire; VH to JH joinings were in frame in 36% of cases. Absent N nucleotides in the DJ border, suggestive of fetal origin of ALL, were seen in 9/40 rearrangements but they did not correlate with younger age. More than one rearrangement was sequenced in six patients, representing independent events with no signs of clonal evolution. One patient was analyzed at first bone marrow relapse showing persistence of one rearrangement and evolution of a second one which conserved the DJ border. The subset of B cell precursors which suffer malignant transformation to ALL appear to be common in different parts of the world.

Adolescent↗
PubMed1996

Evaluation of magnetic resonance imaging for the detection of sacroiliitis in patients with early seronegative spondylarthropathy.

A prospective study was conducted in 23 patients to evaluate magnetic resonance imaging versus computed tomography and plain film radiography for the early detection of sacroiliitis in patients with spondylarthropathy and an Amor score of less than 6. Computed tomography was significantly better than the other two techniques despite some false-positive results, particularly in patients older than 40 years. Magnetic resonance imaging lacked sensitivity for detecting elementary lesions, particularly of the cartilage, but demonstrated clearly that the earliest abnormality was edema of the subchondral bone.

Adult↗
PubMed1996

[Multiple endocrine neoplasia type 2A. Report of a case with an unusually aggressive outcome].

We report a 28 years old woman who consulted for diarrhea of two years and a thyroid nodule. A medullary thyroid carcinoma was diagnosed and a thyroidectomy performed. There was a local relapse two months later and distant metastases were found five months later. A MIBG-1131 scintigraphic image of the adrenals lead to the suspicion of a bilateral pheochromocytoma. The surgical resection of the adrenals confirmed the diagnosis. There was no response to chemotherapy and the patient continued with severe hypercalcemia, repeated infections, persistent diarrhea and cachexia, dying one year after the diagnosis. There was no family history of the disease. We conclude that this is a particularly aggressive presentation of a multiple endocrine neoplasia type 2A.

Adrenal Gland Neoplasms↗
PubMed1995

Lipoxygenase products and expression of 5-lipoxygenase and 5-lipoxygenase-activating protein in human cultured synovial cells.

5-Lipoxygenase products are pro-inflammatory mediators. Their roles and cellular origin in chronic inflammatory rheumatisms such as rheumatoid arthritis (RA) are poorly understood. The expression of arachidonate 5-lipoxygenase (5-LOX, arachidonate: oxygen 5-oxydoreductase; EC 1.13.11.34) and the 5-lipoxygenase activating protein (FLAP) genes in osteoarthritis and RA synoviocytes was studied at the transcriptional level by reverse transcription-polymerase chain reaction (RT-PCR) methodology. Arachidonic acid metabolism was analyzed by reverse-phase high pressure liquid chromatography. 5-LOX and FLAP mRNA were detectable using RT-PCR in all sources of synoviocytes tested. The expression of 5-LOX and FLAP mRNA led to the synthesis of 5-LOX metabolites. 12- and 15-LOX activities were also present. These LOX products can participate in inflammatory processes leading to joint destruction in RA.

5-Lipoxygenase-Activating Proteins↗
PubMed1994

Sodium naproxen: concentration and effect on inflammatory response mediators in human rheumatoid synovial fluid.

Twelve patients suffering from rheumatoid arthritis and having swollen knees were treated with 1.1 g/day of sodium naproxen administered in one dose, daily for 5 days. The 72-h wash-out period was verified by the absence of any nonsteroidal anti-inflammatory drug using a HPLC screening. Blood and synovial fluid samples were drawn just before treatment and 24 h after the last dose. Eicosanoids (PGE2, 6-keto-PGF1 alpha, TXB2, LTB4, LTC4) in synovial fluid were determined by immunoenzymatic assays. In plasma and synovial fluid, hyaluronic acid was assayed by radiometric assay and sodium naproxen by HPLC. Free drug was determined by equilibrium dialysis. Statistical analysis used nonparametric tests. Pain relief (evaluated on a visual scale), morning stiffness, and scores on the Lee and Ritchie indices all decreased significantly, as did PGE2 and LTB4 concentrations. The decrease in 6-keto-PGF1 alpha and TXB2 was not significant. No significant change was found for LTC4 and hyaluronic acid. Total concentrations of sodium naproxen were equivalent in plasma (16.1 micrograms.ml-1) and synovial fluid (18.9 micrograms.ml-1). Free fractions were significantly higher in synovial fluid (0.14%) than in plasma (0.11%), as shown by binding of the drug to human serum albumin, at various protein concentrations. Interestingly, the clinical efficacy, as shown by decreases in morning stiffness and in the Lee index score, correlated with the free concentration of naproxen in synovial fluid.

6-Ketoprostaglandin F1 alpha↗
PubMed1994

Mutational analysis of the Bordetella pertussis fim/fha gene cluster: identification of a gene with sequence similarities to haemolysin accessory genes involved in export of FHA.

The chromosome of Bordetella pertussis harbours a region of 27 contiguous kb, which contains the bvg, fha and fim genes, involved in the co-ordinate regulation of virulence genes, FHA production and fimbriae production, respectively. The linkage of FHA and fimbrial genes has resulted in some confusion concerning the existence and location of genes required for the production of FHA and the function of the fimbrial genes fimB-D, which were proposed to be involved in both FHA and fimbriae biosynthesis. Through the use of non-polar mutations in each of these genes, we found that fimB-D are required for the production of both serotype 2 and 3 fimbriae, but not for FHA biosynthesis. Furthermore, a large open reading frame, designated fhaC, was identified downstream of fimD. It was shown that fhaC is essential for FHA production but not for fimbriae biogenesis. We propose that insertion mutations in fimB-D affect FHA production because of polar effects on fhaC expression. An insertion in the region downstream of fhaC had only a slight effect on FHA and fimbriae production. The fhaC gene product shows homology with ShIB and HpmB, two outer membrane proteins involved in export and activation of the haemolysins, ShIA and HpmA, of Serratia marcescens and Proteus mirabilis, respectively. Homology is also observed between the N-termini of FHA, ShIA and HpmA. Export of the haemolysins requires the N-termini of these molecules, and when this region was removed from FHA by an in-frame deletion, FHA biosynthesis was abolished. These results suggest that the N-terminus of FHA interacts with FhaC, and that as a result FHA is transported across the outer membrane.

Adhesins, Bacterial↗
PubMed1994

The H-NS protein is involved in the biogenesis of flagella in Escherichia coli.

The function of the flagellum-chemotaxis regulon requires the expression of many genes and is positively regulated by the cyclic AMP-catabolite activator protein (cAMP-CAP) complex. In this paper, we show that motile behavior was affected in Escherichia coli hns mutants. The loss of motility resulted from a complete lack of flagella. A decrease in the level of transcription of the flhD and fliA genes, which are both required for the synthesis of flagella, was observed in the presence of an hns mutation. Furthermore, the Fla- phenotype was not reversed to the wild type in the presence of a cfs mutation which renders the flagellum synthesis independent of the cAMP-CAP complex. These results suggest that the H-NS protein acts as a positive regulator of genes involved in the biogenesis of flagella by a mechanism independent of the cAMP-CAP pathway.

Bacterial Outer Membrane Proteins↗
PubMed1994

[The risk/benefit ratio of low-dose cyclosporin in the treatment of severe rheumatoid arthritis].

Although the efficacy of cyclosporine therapy in rheumatoid arthritis has been established, there have been no long term studies of the risk/benefit ratio of cyclosporine A in severe rheumatoid arthritis. A prospective, open-label one-year study included 106 patients (83 women and 23 men; mean age 53 years; mean disease duration, 11 years) with rheumatoid arthritis. Mean number of previous second-line treatments was four and 69% of patients had failed methotrexate therapy. The initial dosage of cyclosporine was 3 mg/kg/d and was increased if needed up to 5 mg/kg/d. The dosage was reduced in the event of serum creatinine elevation (by more than 30% versus baseline) or diastolic blood pressure elevation (above 95 mmHg). The statistical analysis was performed on an intention-to-treat basis. In the 45 patients who completed the one-year study period, the mean dosage was 3.6 +/- 1 mg after six months and 3.3 +/- 1 mg/kg/d after one year. Significant improvements were seen in all the clinical efficacy parameters. The mean reduction in corticosteroid dosage was 0.5 mg/d. The study drug was discontinued prematurely in 61 patients (36 because of adverse events and 21 because of inefficacy). Twelve of the 56 patients with serum creatinine level elevation on at least one occasion and seven of the 35 patients with diastolic blood pressure elevation were taken off the study drug.

Adult↗
PubMed1994

Idiopathic retroperitoneal fibrosis with systemic manifestations.

We describe a previously unreported association of idiopathic retroperitoneal fibrosis with mesenteric, pulmonary and perhaps periarticular fibrotic involvement, and panniculitis resembling Weber-Christian panniculitis. The onset of the disease was uncommon with arthritis. Then, several episodes of migratory panniculitis appeared; biopsy showed septal panniculitis without necrosis of adipose tissue. Considering the patient's anamnesis, it is tempting to speculate that these manifestations all originate from the same mechanism.

Adult↗
PubMed1993

The filamentous haemagglutinin, a multifaceted adhesion produced by virulent Bordetella spp.

Filamentous haemagglutinin (FHA) is the major attachment factor produced by virulent Bordetella spp. Similar to the other virulence factors, its production is tightly regulated by a two-component system in response to environmental changes. Although of impressive size (c. 220 kDa), it is very efficiently released into the culture supernatant of Bordetella pertussis. Its biogenesis involves complex processing of a larger precursor with a calculated molecular mass of 370 kDa. Export of FHA into the culture medium depends on an outer membrane protein homologous to haemolysin accessory proteins. Purified extracellular FHA is able to increase the adherence of other pathogens to the host, which may contribute to super-infection in whooping cough. Although FHA- mutants colonize lungs as efficiently as the wild-type parent strains, immune responses against FHA appear to protect against colonization. Unlike many other adhesins, FHA expresses at least three different attachment activities, one specific for the CR3 integrins of macrophages, one involving a carbohydrate-binding site, specific for interactions with cilia, and a heparin-binding activity that may be important for interaction of B. pertussis with epithelial cells or extracellular matrices.

Adhesins, Bacterial↗