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C Giroud

Publications and source records attributed to C Giroud.

61 records · Page 4Linked to original sources
PubMedDate not supplied

Stability of expression-linked surface antigen gene in Trypanosoma equiperdum.

African trypanosomes evade clearance in immune-competent hosts by periodically replacing their major surface glycoprotein with an antigenically different glycoprotein. Expression of many of these variant surface glycoproteins (VSGs) is associated with the duplication and transposition of silent basic copy genes (BCs) into unlinked genomic expression sites. The new expression-linked VSG gene copies (ELCs) are oriented with their 3' ends proximal to chromosome telomeres. Other VSG genes are activated without the production of an ELC. The 3' ends of these VSG genes are near chromosome telomeres both when they are active and when they are inactive. Recently, we have shown that activation of the VSG-1 gene in the BoTaR (Bordeaux trypanozoon antigen repertoire) serodeme of Trypanosoma equiperdum involves the duplication and transposition of a telomeric BC gene into one of at least three unlinked telomeric sites. Here we show that the VSG-1 ELC is inactivated but not eliminated in some antigenic variants derived from a VSG-1 expressor. In addition, a subsequent variant that again expresses VSG-1 has not reactivated the residual VSG-1 ELC (R-ELC), but instead contains a new, active VSG-1 ELC in an unlinked telomeric site. These results show that the simple presence of an ELC in a potential expression site is not sufficient for its expression.

Animals↗
PubMedDate not supplied

Stable expression of two variable surface glycoproteins by cloned Trypanosoma equiperdum.

African trypanosomes are thought to evade the host immune system by periodically changing their variable surface glycoprotein (VSG). VSG genes are activated by a complex process involving the duplicative transposition of silent basic copy genes to one of several expression sites. These expression-linked copies (ELCs) of the VSG genes are also subject to regulation within expression sites by as yet unknown mechanisms. It is generally assumed that trypanosomes can express only one VSG gene at a time. Nevertheless, the finding that they contain multiple VSG gene expression sites suggests that multiple expression is possible. We show here that Trypanosoma equiperdum can stably express two VSG genes in a simple axenic culture system and that both antigens are present on the cell surface. The two antigens do not co-cap or form heterodimers. Their corresponding genes show no cross-hybridization and are situated in different telomere-linked expression sites. Northern blot analysis reveals that both genes are active in the double expressors.

Animals↗
PubMedDate not supplied

Pharmacokinetic properties of the trypanocidal drug melarsoprol.

With a biological assay and atomic absorption spectrometry we determined the level of melarsoprol in the serum and cerebrospinal fluid of 19 patients treated with melarsoprol in Daloa, Ivory Coast. Most serum levels were between 2 and 4 micrograms/ml 24 h after administration, and were still > or = 0.1 microgram/ml after 120 h. Levels in the cerebrospinal fluid were between 0 and 0.1 microgram/ml. Elimination was biphasic, with a pronounced beta 1 phase. Mean terminal elimination half-life of melarsoprol was about 35 h, volume of distribution was about 100 l and total clearance was about 50 ml/min. The results of these first pharmacokinetic studies on melarsoprol were used to simulate possible alternative therapy schemes which might avoid some of the problems that arise with melarsoprol use.

Adult↗
PubMedDate not supplied

[Acute sinusitus in adults. Management by general practitioners].

OBJECTIVE: Acute sinusitis is a common condition encountered in general practice and raises the question of appropriate management. Sufficient data are still lacking in the literature to provide a fully satisfactory response. METHODS: We conducted a survey among 193 physicians representative of the general practitioners in France to collect 755 cases of acute sinusitis treated in the outpatient setting from January 6 through March 15, 1999. We recorded clinical features and therapeutic management. RESULTS: Pain was the predominant clinical sign (97% of the patients). Facial pain with a highly suggestive localization and aggravated by pressure and headache were the most frequent. Most of the patients also had a nasal symptom (77%) and an infectious context (90%). Three circumstances had been pre-defined by the experts: unique acute sinusitis, acute episode of chronic sinusitis, and recurrent acute sinusitis. In 67% of the cases of unique acute sinusitis, the diagnosis of the general practitioner was confirmed a posterori by the experts. Few complementary tests were ordered (in 17% of the patients) mainly in fragile patients and mainly limited to a radiography of the sinus (81% of the complementary tests ordered). An oral antibiotic was almost always prescribed (96% of the patients) although antibiotics comprised only 29% of all prescriptions. General corticosteroid therapy (41%), local treatment (73%) and anti-cough or expectoration medications (52%) were also prescribed. Despite the painful nature of sinusitis, analgesics were only prescribed for 36% of the patients. CONCLUSION: This observational survey enabled us to describe the diagnostic and therapeutic strategy used by French general practitioners for acute sinusitis in adults. There was general agreement on the strategy that was well adapted to the patient profiles. An evaluation of the different classes of drugs prescribed, and their efficacy in the outpatient setting, that remains to be determined, was not however attempted.

Acute Disease↗
PubMedDate not supplied

[Presentation for the use of a clinical laboratories of standards of metrology (Document A)].

Clinical laboratories shall have a perfect control of "in vitro diagnostic medical devices" to ensure the quality of their analytical results. This introductory presentation to a serie of documents of recommendations tackles the different standards of metrology concerning the requirements to reference materials, metrological traceability, metrological confirmation, management of measurement as well as uncertainty of measurement. The standards concerning clinical laboratories are then succinctly described.

Clinical Laboratory Techniques↗
PubMedDate not supplied

[Recommendations for the installation in the laboratory of metrological functions and corresponding documentation (Document B)].

In order to ensure the quality of analytical results, clinical laboratories shall have a perfect control of process and equipments of measurement. Therefore is recommended individualisation of metrological function, generally entrusted the quality manager. This quality manager will draw up a metrological traceability, verifications and confirmations, control of non conformities, follow-up and evaluation of metrological function.

Clinical Chemistry Tests↗