Germes à tropisme cellulaire (Chlamydiae,Mycoplasmes) et perturbation de la fécondance du sperme

Many factors are liable to be risk factors for fertility in the human male. Among these factors, semen infections are frequently quoted, and more specially semen infections with chlamydia trachomatis and those with mycoplasma. In this review of the literature, the author focused on the potential effects of such chlamydia or mycoplasma infections upon the fertilization ability of spermatozoa, as assessed through semen parameters, fertilization rate     

Infection génitale à chlamydia chez l’homme et retentissement sur la fécondité

Chlamydia trachomatis is responsible for the most common sexually transmitted disease, up to 40% of the non gonococcal urethritis. It is a compulsary intracellular parasite. Its peculiar metabolism makes the bacteria interfere with the host cell immunity. Infection can become chronic and induce inflammation, if not properly treated, by permanent emission of antigens and heat shock proteins, and stimulation of Tcells. Autoimmunization against sperm can occur and impair fertilization and embryo implantation. Thus, Chlamydial infection can be associated with male infertility because of tissue damage, altered movement and antisperm immunization. PCR and LCR are to date the most sensitive detection techniques for c.trachomatis. Our study aim was to determine the prevalence of Chlamydial infection by PCR in 6 groups of men in andrologic practice. The highest prevalences have been found in the infertile men group and in the symptomatic group. No Chlamydia culture was found positive in any group. The association of PCR with anti C. trachomatis seminal IgA and seric IgG are useful tools for andrologic exploration.     

Végétation et climat au Pléistocène inférieur et moyen à La Pineta (Isernia,Italie)

Palynological investigation from the Lower Palaeolithic site of La Pineta (Isernia, Molise) reports the environmental and climatic conditions of an old human occupation site in Italy, between the end of the Lower Pleistocene and the beginning of the Middle Pleistocene. The pollen record shows that the end of the Lower Pleistocene was marked by an arid episode. This is related to change in the climatic cycles periodicity from 41 to 100 ka, which occurred between 900 and 800 ka. The post-archaeological layers show new favourable moisture conditions at the beginning of the Middle Pleistocene, when the 100 ka cycles prevail. To cite this article: V. Lebreton, C. R. Palevol 1 (2002) 11–17.     

Cytochrome P450 et activation génétique — de la pharmacologie à l’élimination du cholestérol et à la régression de l’athérosclérose

Background

Lipoproteins are closely associated with the atherosclerotic vascular process. Elevated levels of highdensity lipoprotein cholesterol (HDL-C) and apolipoprotein AI (apo AI) in plasma indicate a low probability of coronary heart disease (CHD) together with enhanced longevity, and elevated levels of low-density lipoproteincholesterol (LDL-C) and apo B indicate an increased risk of CHD and death. Studies linking gene activation and the induction of cytochrome P450 with elevated plasma levels of apo AI and HDL-C and lowered plasma levels of LDL-C presented a new potential approach to prevent and treat atherosclerotic disease.

Objective and methods

This is a review aimed at clarifying the effects of P450-enzymes and gene activation on cholesterol homeostasis, the atherosclerotic vascular process, prevention and regression of atherosclerosis and the manifestation of atherosclerotic disease, particularly CHD, the leading cause of death in the world.

Results

P450-enzymes maintain cellular cholesterol homeostasis. They respond to cholesterol accumulation by enhancing the generation of hydroxycholesterols (oxysterols) and activating cholesterol-eliminating mechanisms. The CYP7A1, CYP27A1, CYP46A1 and CYP3A4 enzymes generate major oxysterols that enter the circulation. The oxysterols activate — via nuclear receptors — ATP-binding cassette (ABC) A1 and other genes, leading to the elimination of excess cholesterol and protecting arteries from atherosclerosis. Several drugs and nonpharmacologic compounds are ligands for the liver X receptor, pregnane X receptor and other receptors, activate P450 and other genes involved in cholesterol elimination, prevent or regress atherosclerosis and reduce cardiovascular events.

Conclusions

P450-enzymes are essential in the physiological maintenance of cholesterol balance. They activate mechanisms which eliminate excess cholesterol and counteract the atherosclerotic process. Several drugs and nonpharmacologic compounds induce P450 and other genes, prevent or regress atherosclerosis and reduce the occurrence of non-fatal and fatal CHD and other atherosclerotic diseases.     

Végétation et Flore des Monts Nimba

Conclusions Malgré ses enclaves de savance et la prairie, riches en espèces tropicales xérophiles, le territoire étudié appartient incontestablement au domaine forestier guineo-équatorial. Plusieurs climax, tous forestiers, appartenant, suivant les conditions locales, aux ordres des Triplochitetalia, Lophiretalia et Parinarietalia, y sont représentés. En fait, cette végétation primitive est profondément dégradée, aux basses altitudes par les défrichements, et sur les crêtes par les feux. C'est dire tout l'intérêt que présente, dans ce territoire, la protection de la Nature; la mise en réserve naturelle intégrale du massif du Nimba, promulguée en juillet 1944 sur l'initiative de M. le Professeur Heim et de M. le Professeur Monod, Directeur de l'Institut Français d'Afrique Noire, préservera de la destruction les richesses botaniques de cette région montagneuse.Reçue par la rédaction le 10-XI-1950.     

Syndrome de klinefelter et conseil génétique

Klinefelter’s syndrome is a common sex chromosomal aberration generally characterized by hypergonadotrophic hypogonadism and azoospermia. However, spermatogenesis impairment is variable and severe oligozoospermia can be found in some men, particularly those exhibiting a mosaic karyotype 47,XXY/ 46,XY. New reproductive technologies, such as intracytoplasmic sperm injection (ICSI), allow Klinefelter patients to have a progeny, even those who are azoospermic after testicular sperm recovery. The question therefore arises of whether or not there is a genetic risk for pregnancies from affected fathers. Sperm karyotyping, by in vitro penetration of zona-free hamster eggs or by fluorescence in-situ hybridization (FISH), is a method of choice for measuring aneuploidy rate in spermatozoa of patients carrying gonosomal abnormalities. A theoretical model would predict a high level of 24,XX and/or 24,XY disomic sperm cells in Klinefelter patients if 47,XXY spermatogonia were able to complete meiosis and achieve spermatogenesis. Interestingly, current observations show that the rate of abnormal spermatozoa in these patients is low, around 1–2%, which indicates that only 46,XY spermatogonia can produce mature sperm cells and that oligozoospermic Klinefelter patients probably carry a 47,XXY / 46,XY mosaicism, at least at the testicular level. However, this low but statistically significant level of disomic spermatozoa emphasizes the fact that their spermatogenesis occurs in a compromised environment which could increase the risk of meiotic errors. Therefore, the possible occurrence of autosomal aneuploidies in children born from Klinefelter fathers leads to the following recommendations: a) individual analysis by FISH of the sperm aneuploidy rate in each Klinefelter patient candidate for ICSI; b) proposal of fetal karyotyping after amniocentesis in pregnancies obtained by this technique.     

Apports de la géologie et de la géomorphologie à l’étude du mégalithisme : identifier,interpréter,dater

The contribution of geology and geomorphology to architectural and technological study of the Atlantic coast of France megaliths is important and can be grouped into three main axes: to identify, interpret and dating. Identification refers to the sourcing of the megalithic materiel from 0 to 7 km, sometimes around 10 km, or even exceptionally around 30 km. It is never the entire supply that is affected by such long distances but only a few blocks, some of them are remarkably well staged in the megalithic architecture. Another contribution lies in a fresh look at the management of stone recognized through the modes of acquisition, transformation and use of the raw material. More particularly, the geomorphology associated with technological reading offers tools for recognizing ancient standing stones. In the context of the interpretation of funerary chambers, the two sciences open a large window on the modalities of the internal structuring of monuments. From the entrance to the end of the chamber, the organization and use of the space is documented, sometimes a symbolic coding emerges from the mineral walls. This symbolic coding is based on particular petrography, on surface conditions operating a subdivision of space, on granulometries and homogeneities of differentiated surfaces. The internal organization can also be marked with natural “patterns”, which refer to a completely new aspect of Neolithic thought. Finally, the last axis concerns relative dating, by recognizing forms of postmegalithic fossil erosion, geomorphology makes it possible to identify reused stelae. A very important tool in a current research context where an important episode of reuse of standing stones at the end of the middle Neolithic is anticipated in the construction of dolmens in the south of France.     

Méthodologies et générations d’aérosol innovants appliqués à la vectorisation pulmonaire en pédiatrie

No aerosol system on the market is perfectly suited for aerosol therapy in infants. The RESPIRE project aims to answer this need by developing an innovative piezoelectric microperforated vibrating membrane nebulizer, the Baby Nimbus?; efficient, fast, portable and silent. Consisting of three complementary partners, the project was divided into three phases: technology development by the company Télémaq (Sophia Antipolis), in vitro and in vivo test performed on baboons by Inserm U618 (Tours), clinical trials in infants led by AP–HM (Marseille). Studies conducted by Inserm U618 and AP–HM focused on the influence of particle size on lung deposition in baboons and the clinical score in infants. Three devices of different droplet sizes were compared in the in vivo study, the Pari LC Sprint SP^® (Pari, Germany, MMAD 4.5μm – flow 0.18 mL/min), the E-Flow Rapid^® (Pari, Germany, MMAD 4.8μm – flow 0.35 mL/min) and Baby Nimbus? (Télémaq, France). Four versions of Baby Nimbus? were needed to achieve the MMAD of 2.4 μm and flowrate of 0.4 mL/min (Spraytec^®, Malvern, England). Preliminary in vivo results show that the amount of the initial charge deposited in the lungs is 0.9% for the Pari LC Sprint SP^®, 1.2% for E-Flow Rapid^® and 2.2% for the Baby Nimbus?. Additional in vivo tests and clinical trials are under way to rule definitively on the efficiency provided by the Baby Nimbus?.