Search PubMed⌕ Search

Biomedical subjects

P Bertin

Publications and source records attributed to P Bertin.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Aspirin, pain and inflammation].

SUBJECT: Acetylsalicylic acid (ASA) is among the most commonly analgesic, antipyretic and anti-inflammatory used drugs. The anti-inflammatory effects of ASA are mediated by the inhibition of cyclooxygenase enzymes with the subsequent decrease of prostaglandin synthesis. NEW DATA: However, since this discovery of Vane in 1971, much of other mechanisms of anti-inflammatory action, without relation with cyclooxygenases, have been proposed. ASA has peripheric analgesic properties by reducing prostaglandin biosynthesis. But there is evidence that the analgesic effects could be mediated by central mechanisms with changes in the monoaminergic and opioid systems. ASA is essentially used in moderate pains with an inflammatory component (rheumatological disorders, headaches, dental and postoperative pains). PERSPECTIVES: The clinical use of ASA at anti-inflammatory dose is less frequent because the other non steroidal anti-inflammatory drugs are as effective as ASA, but they are associated with less side effects. Nevertheless, the synergism of ASA and morphine association and the possible involvement of the central serotonergic and opiatergic systems in the antinociceptive activity of ASA could confer a greater role of ASA in pain management.

Adult↗
PubMed2000

Isolation and characterization of vicH, encoding a new pleiotropic regulator in Vibrio cholerae.

During the last decade, the hns gene and its product, the H-NS protein, have been extensively studied in Escherichia coli. H-NS-like proteins seem to be widespread in gram-negative bacteria. However, unlike in E. coli and in Salmonella enterica serovar Typhimurium, little is known about their role in the physiology of those organisms. In this report, we describe the isolation of vicH, an hns-like gene in Vibrio cholerae, the etiological agent of cholera. This gene was isolated from a V. cholerae genomic library by complementation of different phenotypes associated with an hns mutation in E. coli. It encodes a 135-amino-acid protein showing approximately 50% identity with both H-NS and StpA in E. coli. Despite a low amino acid conservation in the N-terminal part, VicH is able to cross-react with anti-H-NS antibodies and to form oligomers in vitro. The vicH gene is expressed as a single gene from two promoters in tandem and is induced by cold shock. A V. cholerae wild-type strain expressing a vicHDelta92 gene lacking its 3' end shows pleiotropic alterations with regard to mucoidy and salicin metabolism. Moreover, this strain is unable to swarm on semisolid medium. Similarly, overexpression of the vicH wild-type gene results in an alteration of swarming behavior. This suggests that VicH could be involved in the virulence process in V. cholerae, in particular by affecting flagellum biosynthesis.

Amino Acid Sequence↗
PubMed2000

Drug-induced rheumatic disorders: incidence, prevention and management.

The purpose of this article is to review the causes, the clinical manifestations and the management of the more frequent drug-induced rheumatic disorders. These include: (i) articular and periarticular manifestations induced by fluoroquinolones, nonsteroidal anti-inflammatory drugs, injections of corticosteroids, and retinoids; (ii) multisystemic manifestations such as drug-induced lupus and arthritis induced by vaccination, Bacillus Calmette-Guerin therapy and cytokines; (iii) drug-induced disorders of bone metabolism (corticosteroid-induced osteoporosis, drug-induced osteomalacia and osteonecrosis); and (iv) iatrogenic complex regional pain syndromes. Disorders caused by nonpharmacological and rarely used treatments have been deliberately excluded. Knowledge of these drug-induced clinical symptoms or syndromes allows an earlier diagnosis and treatment, and earlier drug withdrawal if necessary. With the introduction of new medications such as the recombinant cytokines and antiretroviral treatments, the number of drug-induced rheumatic disorders is likely to increase.

Animals↗
PubMed2000

Articular diffusion of meloxicam after a single oral dose: relationship to cyclo-oxygenase inhibition in synovial cells.

OBJECTIVE: To investigate the distribution of meloxicam in the human knee joint and to compare it with the inhibition of cyclo-oxygenase (COX) activity in synovial cells. DESIGN: Prospective pharmacokinetic study and in vitro laboratory investigation. PATIENTS AND PARTICIPANTS: 42 male and female patients aged 26 to 85 years hospitalised for rheumatic disease and requiring a diagnostic and/or therapeutic knee puncture. METHODS: After a single oral dose of meloxicam 15mg, synovial fluid and blood samples were collected once per patient at various intervals after administration. Meloxicam concentrations were determined by a validated high performance liquid chromatography assay, protein binding by equilibrium dialysis, and pharmacokinetic parameters were calculated by noncompartmental analysis from the mean drug concentration-time profiles. The inhibitory effect of meloxicam on COX activity was investigated separately in unstimulated or interleukin-1beta-stimulated human synovial cells from osteoarthritic patients. RESULTS: Meloxicam was found in synovial fluid at the earliest sampling time (1 hour). Peak concentrations were reached approximately 6 hours postdose in both plasma (842 microg/L) and synovial fluid (320 microg/L). A plateau was observed after the distribution phase (6 hours), corresponding to a constant ratio of drug concentration between synovial fluid and plasma of about 0.47. This ratio was higher in patients with acute inflammation (0.58) than in those with no inflammation (0.38). Meloxicam was extensively bound to protein, mainly to serum albumin. The area under the drug concentration-time curve (AUC) in plasma was more than 2.5 times that in synovial fluid. The AUC for free meloxicam was similar in plasma and synovial fluid. The 50% inhibitory concentrations (IC50) for basal and stimulated COX activity in human synovial cells were 33.7 nmol/L (11.8 microg/L) and 2.0 nmol/L (0.70 microg/L), respectively. The free concentration of meloxicam in synovial fluid was higher than the IC50 for stimulated COX activity from 6 to 36 hours postdose. CONCLUSION: On the basis of free synovial concentrations and the IC50 for stimulated COX activity, meloxicam is expected to have a long duration of action. Inhibition of COX activity is expected to be more marked in inflamed synovium compared with non-inflamed synovium.

Administration, Oral↗
PubMed2000

Current use of analgesics for rheumatological pain.

Rheumatological pain is the most frequent pain doctors have to deal with. Faced with a patient experiencing pain, the clinician must work towards global management of the patient, including the prescription of analgesics. The results of a European survey amongst 722 general practitioners, rheumatologists, orthopaedic surgeons and internal specialists showed that about half of all patients treated for moderate-to-severe pain suffered from musculoskeletal pain. Despite this high treatment frequency, the management of rheumatological pain was generally perceived as problematic by the respondents. The drugs prescribed to treat rheumatological pain differed from country to country, but NSAIDs were generally the most-prescribed substances. Important reasons given for selecting analgesics included efficacy and tolerability, but also tolerance and addiction potential. NSAIDs are common first-line drugs, but their adverse reactions and interactions have led to paracetamol being recommended more often in this role. However, it has been recently demonstrated that the efficacy of paracetamol is often inadequate. On the other hand, the reduced risk of GI toxicity of the new COX-2 selective inhibitors could assure them a major role in mild-to-moderate rheumatological pain treatment. When any of these drugs are no longer effective, or when a patient cannot tolerate their adverse reactions, weak opioids should be considered. Tramadol is one such drug, which is gaining popularity for the treatment of moderate-to-severe rheumatological pain. Finally, strong opioids should be used in selected patients when all other options have been exhausted.

Analgesics↗
PubMed1999

The structural and functional organization of H-NS-like proteins is evolutionarily conserved in gram-negative bacteria.

The structural gene of the H-NS protein, a global regulator of bacterial metabolism, has been identified in the group of enterobacteria as well as in closely related bacteria, such as Erwinia chrysanthemi and Haemophilus influenzae. Isolated outside these groups, the BpH3 protein of Bordetella pertussis exhibits a low amino acid conservation with H-NS, particularly in the N-terminal domain. To obtain information on the structure, function and/or evolution of H-NS, we searched for other H-NS-related proteins in the latest databases. We found that HvrA, a trans-activator protein in Rhodobacter capsulatus, has a low but significant similarity with H-NS and H-NS-like proteins. This Gram-negative bacterium is phylogenetically distant from Escherichia coli. Using theoretical analysis (e.g. secondary structure prediction and DNA binding domain modelling) of the amino acid sequence of H-NS, StpA (an H-NS-like protein in E. coli), BpH3 and HvrA and by in vivo and in vitro experiments (e.g. complementation of various H-NS-related phenotypes and competitive gel shift assay), we present evidence that these proteins belong to the same class of DNA binding proteins. In silico analysis suggests that this family also includes SPB in R. sphaeroides, XrvA in Xanthomonas oryzae and VicH in Vibrio cholerae. These results demonstrate that proteins structurally and functionally related to H-NS are widespread in Gram-negative bacteria.

Amino Acid Sequence↗
PubMed1999

Treatment of the postenucleation socket syndrome with a new hydroxyapatite tricalcium phosphate ceramic implant.

PURPOSE: Surgical correction of the postenucleation socket syndrome (PESS) is challenging. Various biomaterials are used for reconstruction of the anophthalmic orbit, often with unsatisfactory long-term results. Implants have been placed between the periorbital and the orbital floor. The authors describe a new material composed of hydroxyapatite tricalcium phosphate (HA-TCP) in the form of ceramic blocks, to be placed into the orbital fat as a new surgical site. METHODS: Ten patients with PESS underwent surgery to compensate the volume deficit of the anophthalmic orbit. Blocks of HA-TCP were created by fragmentation of a larger piece, tailored as needed, and implanted in the orbital fat. The patients were monitored regularly with clinical and radiologic examinations to evaluate the behavior of the implants. RESULTS: The volume of the HA-TCP was measured in 5 cases (mean, 2.95 +/- 1.08 ml). A significant reduction of enophthalmos was obtained: mean Hertel exophthalmometry measured 12.7 +/- 2.5 mm preoperatively and 14 +/- 2.4 mm postoperatively (p < 0.05). The average prosthesis volume was significantly reduced in the cases measured: 2.7 ml +/- 0.94 ml preoperatively and 1.8 +/- 0.7 ml postoperatively (p < 0.02). There was a negative correlation between the HA-TCP implant volume and postoperative prosthesis volume (correlation coefficient = -0.925; p < 0.05). According to photographic evaluation, correction of the enophthalmos and of the superior sulcus depression were obtained in 70% and 90% of cases, respectively. Magnetic resonance imaging seems to demonstrate that the blocks become well integrated into the surrounding orbital tissue. CONCLUSION: The HA-TCP blocks correct some anomalies of PESS. Placement of the blocks directly into the orbital fat is a promising alternative to the traditional subperiosteal location.

Adolescent↗
PubMed1999

Multiple control of flagellum biosynthesis in Escherichia coli: role of H-NS protein and the cyclic AMP-catabolite activator protein complex in transcription of the flhDC master operon.

Little is known about the molecular mechanism by which histone-like nucleoid-structuring (H-NS) protein and cyclic AMP-catabolite activator protein (CAP) complex control bacterial motility. In the present paper, we show that crp and hns mutants are nonmotile due to a complete lack of flagellin accumulation. This results from a reduced expression in vivo of fliA and fliC, which encode the specific flagellar sigma factor and flagellin, respectively. Overexpression of the flhDC master operon restored, at least in part, motility in crp and hns mutant strains, suggesting that this operon is the main target for both regulators. Binding of H-NS and CAP to the regulatory region of the master operon was demonstrated by gel retardation experiments, and their DNA binding sites were identified by DNase I footprinting assays. In vitro transcription experiments showed that CAP activates flhDC expression while H-NS represses it. In agreement with this observation, the activity of a transcriptional fusion carrying the flhDC promoter was decreased in the crp strain and increased in the hns mutant. In contrast, the activity of a transcriptional fusion encompassing the entire flhDC regulatory region extending to the ATG translational start codon was strongly reduced in both hns and crp mutants. These results suggest that the region downstream of the +1 transcriptional start site plays a crucial role in the positive control by H-NS of flagellum biosynthesis in vivo. Finally, the lack of complementation of the nonmotile phenotype in a crp mutant by activation-deficient CAP mutated proteins and characterization of cfs, a mutation resulting in a CAP-independent motility behavior, demonstrate that CAP activates flhDC transcription by binding to its promoter and interacting with RNA polymerase.

Bacterial Proteins↗
PubMed1999

Long-term cyclosporin continuation rates in rheumatoid arthritis patients.

OBJECTIVE: To evaluate the continuation rate of cyclosporin therapy in rheumatoid arthritis patients followed for at least three years. METHODS: Retrospective medical chart review of rheumatoid arthritis patients on cyclosporin. Treatment efficacy was assessed based on a visual analog scale pain score, Ritchie's articular index, and Lee's functional index. Nonparametric Kaplan-Meier survival curves were used to evaluate continuation rates. RESULTS: 24 cyclosporin-treated patients with a mean age of 58 years and a mean disease duration of ten years were included in the study; 87% had received three second-line drugs prior to cyclosporin. Mean cyclosporin treatment duration was 28 months (range, 1-103 months). Overall cyclosporin continuation rates were 75% after four months and 50% after 36 months. Toxicity and inefficacy caused 33% and 13% of cyclosporin discontinuations, respectively. CONCLUSION: The continuation rate of cyclosporin was satisfactory and similar to that reported for other second-line drugs.

Adult↗
PubMed1999

Remitting seronegative symmetrical synovitis with pitting edema (RS3PE): a form of paraneoplastic polyarthritis?

OBJECTIVE: To describe the clinical and laboratory features and outcome of 6 patients presenting with remitting seronegative symmetrical synovitis with pitting edema (RS3PE) revealing a solid tumor. METHODS: Patients with RS3PE who presented with a solid tumor and who had been seen between January 1, 1994, and December 31, 1996, were included in a retrospective multicenter analysis. These patients fulfilled McCarty's description of RS3PE and the following criteria: (1) bilateral pitting edema of both hands, (2) sudden onset of polyarthritis, (3) age >50 years, and (4) absence of rheumatoid factor (RF). RESULTS: Six male patients with RS3PE are described, of mean age 74 years (range 72-78), presenting prostatic (n = 4), gastric (n = 1), and colic (n = 1) adenocarcinomas. The clini cal picture was characterized by the classical form of RS3PE syndrome and by a deterioration in general condition, sometimes with fever. All patients were negative for RF and antinuclear antibodies. In 2 cases of prostatic adenocarcinoma serum levels of interleukin 6 (IL-6) were high, but decreased with treatment. In these 6 patients, the articular manifestations regressed totally or partially in response to corticosteroids, sometimes at low doses, associated in most cases with specific antitumoral therapy. None displayed erosion or distal bone destruction. The mean survival following discovery of RS3PE was 11 months (range 6-18), 5 patients dying of metastatic dissemination of their cancer and the 6th of myocardial infarction. CONCLUSION: RS3PE is a heterogeneous syndrome that can reveal a solid tumor, notably an adenocarcinoma. There exist no specific criteria to define its forms, but this syndrome should be kept in mind in the face of a deterioration in general health. Although the pathogenic mechanism is unknown, this could involve a type of paraneoplastic polyarthritis linked to the synthesis of a factor such as IL-6.

Aged↗
PubMed1998

[Rheumatoid polyarthritis: therapeutic management].

AN OPEN QUESTION: Developing a therapeutic strategy for rheumatoid arthritis is a difficult and much debated task. Recent clinical trials have confirmed the importance of initiating treatment at the onset of disease in all patients with rheumatoid arthritis in order to limit the degree of later progression. INDIVIDUALIZED REGIMENS: Treatment for patients with early-stage rheumatoid arthritis should be adapted individually taking into consideration the expected benefit and risks of drug therapy, the degree of joint inflammation and factors predictive of disease severity which are becoming more and more well understood. PATIENTS IN REMISSION: Treatment should be continued if well tolerated. Treatment should not be discontinued (and then only progressively) unless complete remission has been achieved for a long period. LONG-STANDING DISEASE: The precise therapeutic strategy in patients with long-standing disease remains a question of debate, but does require full-dose combination regimens.

Anti-Inflammatory Agents↗
PubMed1998

[Male osteoporosis].

AN UPCOMING PUBLIC HEALTH PROBLEM: There has been a considerable focus on osteoporosis in men recently. Bone mass is high in men who have larger bones than women. The frequency of fractures is also higher due to post-trauma lesions. Femoral neck fractures have also increased over the last few years although the F/M ratio remains about 2.8. Overall, there is a trend towards an increased incidence of masculine osteoporosis (and vertebral fractures) due to population aging. FAVORING FACTORS IN MEN: The most important factors are hypoandrogenism, hypoestrogenism (pre or post-puberty), the alcohol-smoking association, malnutrition, lack of sun exposure and chronic liver disease. Other causes of osteoporosis (hyperthyroidism, Cushing's disease, hemochromatosis, gastrectomy, inflammatory rheumatic disease, tubulopathy, hypercalciuria and iatrogenic causes) should also be taken into consideration. PRETHERAPY WORK-UP: All the different possible etiologies should be investigated. Therapeutic protocols should provide hormone replacement when required, withdrawal of causal drugs, better nutrition and reduced alcohol and tobacco use.

Bone Density↗