Rôle pathogène des mouches

Flies are pathogenic for human for many reasons. They can carry a lot of germs (bacterium, virus, parasites). Flies are exceptional intermediate host of parasites (Thelazia). Some are vectors of diseases, as glossina which transmit sleeping sickness, and the tabanidae the loiasis. But the most frequent pathogenicity is due to the larvae, which are under the skin or in natural cavities, as eyes, ears and nose.These myiasis are provoked by different flies as Musca, Cordylobia, Dermatobia, Gasterophilus or Hypoderma. Lucilia is useful because it cleans the wounds. Diagnosis of myiasis is set up by the extraction of the larva and its typing, and in some cases of visceral myiasis by the serodiagnosis. There is only a symptomatic treatment.     

Systèmes de vigilance : Systèmes de surveillance de santé publique

In France, reactions of public health decision makers were done step by step, within a context often marked by crises, such as that of contaminated blood. It resulted the development of multiple vigilance systems. All vigilance systems have in common a public health objective, the necessity to have information on the actions of the system of health and their consequences. In this article, we define a vigilance system as a public health surveillance system, i.e. a finalised information system, built as a continuous process of standardised collection, analysis and diffusion of data, to allow fast decision-making concerning one or more facets of the activities of the health system. We describe the activities of a vigilance system, and specify steps for implementing such a system. The article ends in a proposal for a mode of evaluation common to all vigilance systems.     

Le Demodex : Commensal ou pathogène ?

Demodex is a small worm-like mite, very frequent in sebaceous glands, eyeclash follicles, on the nose and the forhead. The symptoms due to this parasite are discussed (blepharitis, rosacea). The diagnosis is based on the Demodex found in cutaneous squama, in eyelashes, or sometimes in skin biopsy. Treatment consists essentially of a topical application of antiparasitic agents.     

Les pièges de l'antibiogramme

The disk method and, more and more often, automated methods are used for antimicrobial susceptibility testing. Standardisation, automation and computerisation allow to reduce significantly technique errors. However, in his daily practice, the microbiologist must deal with difficulties in the interpretation of in vitro susceptibility testing. These difficulties are due to the bacteria's versatility and to the inability of certain methods to detect in vitro resistance mechanisms. Expert systems and a good knowledge of the methods used are necessary to help the microbiologist.     

Les transporteurs d'oxygène à base d'hémoglobine

The modified hemoglobins are not true blood substitutes because they do not possess the complex functions of erythrocytes. They are oxygen carriers only with a short intravascular life, adapted for temporary use. Three types of modified hemoglobin solutions have been designed, prepared from human or bovine hemoglobin or by genetic engineering. These hemoglobins are highly purified to eliminate trace amounts of stroma, lipids and endotoxins, which are responsible for acute toxicity. They are modified by internal cross linking between the monomers, or by binding to macromolecules. Afterwards, they can be polymerized or encapsulated in liposomes. The purpose of these modifications is to increase oxygen delivery to tissue, to reduce the dissociation into monomers and to guard against oxydation into methemoglobin. The modified hemoglobin solutions are essentially used in hemorrhagic shock and perioperative hemodilution. These oxygen carriers could be used by some athlets to increase their results in particular during endurance sports. But these hemoglobins are different enough from physiologic hemoglobins (normal or pathological), so they could be easily detected in blood samples.     

Apoptose et pouvoir pathogène des bactéries

A growing number of bacterial pathogens and their toxins is shown to be able to cause apoptosis of their target cells. It looks as if the goal is for the microorganism to delete cells of the innate immune system such as macrophages in order to achieve survival within infected tissues. An alternative goal may be to initiate inflammation. Activation of caspase-1, a cysteine protease activating IL-1b and causing the apoptotic death of infected cell accounts for this dual function. This is the case for Shigella, a bacterial species whose capacity to cause apoptotic death of macrophages has been studied in details. For most of the pathogens causing apoptosis of their target cells, three major questions remain unanswered: what are the precise mechanisms inducing programmed cell death? Does this process occur in vivo? What is the advantage for the pathogen?     

Actualisation du système de Bethesda

The Bethesda system is a system of terminology for reporting the results of cervical cytology. It has been developed since 1988 and is widely used in the US and has been recommended by the ANAES. This system has been updated in April 2001. The most important modifications are the following: the suppression of the category « satisfactory but limited by å, the reintegration of benign modifications in the normal category, « atypical squamous cells of undetermined significance å which have been named « atypical squamous cells å and subdivided in « atypical squamous cells of undetermined significance å and « cannot exclude high grade squamous intraepithelial lesion å and endocervical adenocarcinoma in situ which is now a separate entity. The low grade squamous intraepithelial lesions and high grade squamous intraepithelial remain unchanged. Recommendations have been proposed concerning automated review and ancillary testing.     

Les émulsions de fluorocarbures (PFC) : Des transporteurs d'oxygène injectables efficaces et facilement détectables

Perfluorocarbons (PFCs) are derived from straight-chain or cyclic hydrocarbons in which all the hydrogen atoms have been replaced by fluorine. These molecules have a range of remarkable properties including exceptional chemical and biological inertness, and a high gas-dissolving capacity. These latter properties are used as oxygen carriers (blood substitutes): PFC emulsions are being developped to be used for oxygen delivery in different clinical settings.During the past years there have been rumours that these emulsions could be used as doping agents, to obtain enhanced physical performances, because of their ability to carry and deliver oxygen. Absent in urine, they can easily be detected in the blood and expired air which should deter athletes from illicit use.