Relations entre la teneur en sélénium et celle de seize éléments dansHelminthia echioides etTrifolium repens se developpant sur sols argileux

Résumé Nous avons analysé la teneur en sélénium de sols argileux de la région de La Roche-Posay ainsi que celle deHelminthia echioïdes etTrifolium repens qui s'y développent. Sur trente emplacements, la concentration en Se total du sol varie de 1,7 à 4,5 ppm et le pH oscille de 6,1 à 7,2. La teneur en sélénium des plantes est élevée: de l'ordre de 2 à 32,5 ppm, mais aucune corrélation n'a été notée entre ces valeurs et d'une part le pH du sol ou d'autre part la teneur totale en Se du sol.Seize éléments minéraux ont également été dosés. Les deux espèces présentent des concentrations élevées en Al, Fe, Ni, Co et Cr. Les Teneurs les plus fortes en Se ont été retrouées dans les plantes possédant les taux les plus bas en Al, Fe, As et Mn. Chez Trifolium, une corrélation négative est observée entre la concentration en Se et celle en Al (r=–0,44), en Fe (r=–0,47) et en As (r=–0,47). Par ailleurs, des corrélations positives sont obtenues entre les teneurs en Al, Fe et As chez les deux espèces.Une corrélation positive existe entre la teneur en Se et celle en P chez Helminthia, mais chez Trifolium les plus faibles concentrations en Se se retrouvent à la fois dans les échantillons présentant les niveaux les plus faibles et les plus forts en P.Chez l'une ou l'autre des espèces étudiées, des corrélations positives apparaissent entre les teneurs en Se et celles en Co, Mo ou même Mn lorsqu'il est présent à des taux relativement élevés dans la plante.     

Dosage du fer et de l'aluminium échangeable dans les minéraux argileux et dans les sols

Résumé Une méthode est proposée pour le dosage du fer et de l'aluminium échangeable dans les minéraux argileux et dans les sols. La méthode est basée sur l'extraction successive des oxinates de fer et d'aluminium en fonction du pH.Les conditions optimales et l'influence des divers facteurs déterminant l'extraction quantitative et sélective de ces deux éléments ont été préalablement étudiées.Publication du Centre de Chimie Biologique et Colloïdale du sol subsidié par I'I.R.S.I.A.     

Combinaison de deux actions antimitotiques différentes: dioxyde de sélénium et hydrate de chloral

Two antimitotic substances with different effects have been combined: the first, chloral hydrate M/10, destroys the achromatic fibers after a delay of about 1 h and a half to 2 hours; however, in this case chromosomes are not affected. The second, selenium dioxyde M/100, alters the chromosomes, without destroying the fibers, after a delay of forty five minutes to 1 h; however, it sometimes provokes the blockade of the centrosphere in the shape of a dense smooth bowl which is as voluminous as it is during the normal metaphase. When both substances are combined under conditions of maximum action, fibrillae are destroyed, but the centrosphere stays blocked. With chloral alone this blockade does not occur. As a consequence of the successive actions of chloral and selenium (each drug used respectively during half the time) the two primitive poles, which are still provided with inactive and fibrilless centrospheres, appear separated from a pluripolar spindle, the poles of which are active, but devoid of centrospheres. Therefore the action of selenium dioxide is qualitatively different from the action of chloral, and the various functions of the centriole (including gathering of the centrosphere material, fibrillogenesis and division of the center) could be separately damaged.     

Place de l’analyse du mouvement dans un bilan de fertilité: Valeurs prédictives des différents paramètres mesurés

Routine evaluation of semen characteristics-spermiogram-includes estimation of the percentage of motile sperm; however it does not provide quantitative informations about sperm movement characteristics, except under the form of qualitative appreciations (slow, sluggish, yawing, non progressive, etc.). Flagellar function is indeed directly involved in the migration of spermatozoa through the female genital tract, and in the fertilization process by itself (migration through the zona pellucida requires special motility state, generally called “hyperactivation”). Sperm flagellar movements can now be indirectly investigated by analysing movements of sperm head, which are more easily detectable under phase contrast illumination: video signals are digitalized then sperm tracks are reconstructed by the computer from coordinates of sperm centroids (these systems are called “computer-assisted semen analysis” or “CASA”). CASA systems are now so performing and rapid that sperm movement analysis (SMA) can be proposed in the same time of routine semen analysis. However SMA, together with other functional tests, offer more interest in some particular situations as unexplained infertility, or unexpected failure of IVF. Numerous studies have tried to identify the most discriminant parameters, generally by means of multiple regression analysis. The interpretation of litterature data is difficult because of several differences in the protocol design, concerning either the measurements conditions (before or after sperm washing and selection) or the nature of the functional test: migration into cervical mucus, zona-free hamster egg penetration, IVF, etc. Moreover, the most discriminant factors are generally represented by classical parameters as % of normal forms or of motile sperm. In the present study we showed that only the factor “% of motility” allowed a significant discrimination according to different classes of fertilization rate (FR) in an IVF system. FR increased with hyperactivation rate (HA), but the statistical test was not significant. However, the more numerous cases of IVF failure were found in the group corresponding to very low HA rate (0–5%). We conclude that one major interest of SMA is to reveal some flagellar dyskinesia (i.e. corresponding to low values of amplitude lateral displacement of the head, or straight line velocity). These cases could then benefit of assisted reproductive techniques well adapted to this motion dysfunction, as subzonal insemination (SUZI) or intra-cytoplasmic sperm injection (ICSI).     

Etude du transfert de quelques oligo-éléments dans les chaînes trophiques néritiques et estuariennes: Accumulation biologique chez les poissons omnivores et super-carnivores

Five species of fishes(Dicentrarchus labrax, Gobius microps, Stizostedion lucioperca, Gadus luscus, Merlangius merlangus) and their major prey organisms were collected monthly from two stations in the Loire estuary (France). The levels of several trace elements (Cd, Pb, Cu, Zn) in their tissues were determined by means of atomic absorption spectrophotometry. The concentrations of Cd, Pb and Cu were shown to decrease in the highest trophic levels: the relatively highest metal levels were determined in annelids, followed by crustaceans, the lowest levels being encountered in fishes. However, a preferential uptake of Cu was observed in crustaceans. There is no biomagnification for these three metals, the concentrations in preys being generally lower than in predators. For Zn, the highest concentrations were measured in worms and copepods but preys such as shrimps and mysids exhibit values of the same order of magnitude compared to predator fishes.

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Avec la collaboration technique de R. Ferre.     

Action de dérivés du sélénium (séléniates et sélénites) comparée à celle d'acides divers (crotonique,acétique,citrique et phosphorique) sur les mitoses de segmentation

The action of seleniates and selenites on the segmentation mitoses is similar to that of SeO₂: polar dissociation with conserved dominance of the principal pole, stickiness and clumping of chromosomes. Crotonic and acetic acid dissociate more strongly the achromatic apparatus, which is resolved into divergent fibrillae, which are sinuous and irregularly fasciculated; the principal poles may be recognized, but their activity is more lessened: centrospheres are reduced to orangeophilic material. All these derivatives are acidic in the solutions. When the action of crotonic acid is interrupted, fibrillogenesis does not recover, but cellular centers start again to divide and the size of centrospheres enlarges by assemblage of dis-oriented cyanophilic material, arising from destroyed fibrillae. Reduction of fibrillogenesis by inactivation of the poles results in reactivation of fibrillogenesis in the diastema, expansion of the fibrillar ?clear zone? and its budding into numerous elements filling the animal hemisphere. Furrowing is consequently inhibited. Classification of mitotic dissociation is reviewed: equilibrated pluripolar mitoses (phenylurethane), pluripolar systems hierarchically organized (selenium dioxyde), pluripolar systems practically not hierarchically organized (crotonic and acetic acids).     

Utilisation des lichens dans la mise en évidence des éléments traces présents dans les cours d'eau

The authors demonstrated the possibility to use lichens as biodetectors of the presence of copper and cadmium in rivers. The authors showed that the lichen biomass fixes rapidly metals in solution. This caption is proportional to the quantity of metal present, without any toxic threshold being observed, even at high concentration levels. Furthermore, Dermatocarpon luridum (With.) Laundon syn. D. weberi (Ach.) Mann was a better biodetector of metallic micropolluants than other aquatic macrophytes (brypophytes and phanerogames). Transplantations of this lichen were made in the Vienne river (Massif Central, France) in the upstream and downstream section of an electrolytic copper refining plant. The results revealed an aquatic pollution generated by this industry.     

Les premiers vertébrés et les premières étapes de l’évolution du crâne

The earliest vertebrates and the first steps of the evolution of the skull. Vertebrates are one of the few metazoan taxa, which display a well-corroborated phylogenetic pattern, a good and anatomically informative fossil record, and a relatively slow ontogenetic development. They are thus a favourite taxon for illustrating evolution as a historical process, although the stem of the vertebrate tree remains poorly documented by fossils, except for some Early Cambrian forms. Therefore, the characterization of the vertebrates now rests essentially on a small number of developmental characters, mostly involved in the rise of the skull, and whose precursors may occur in other chordates. The tree of the crown-group vertebrates also shows some major morphological gaps due to early extinctions, but a number of Palaeozoic stem gnathostome taxa helps in documenting the agnathan-gnathostome evolutionary transition. However, stem cyclostomes remain elusive.     

Histologie testiculaire et études méiotiques dans les stérilités de type non obstructif

There has been a renewed interes in testicular biopsy to evaluate infertility since the introduction, in 1993, of ICSI in azoospermic men with testicular sperm extraction (TESE) and intracytoplasmic sperm injection for the treatment of obstructive azoospermia. TESE is now performed for the treatment of nonobstructive azoospermia, and the testicular material sampled for therapeutic purposes can also be used for diagnostic and research purposes. The development of new methods of investigation of spermatogenesis, such as immunocytochemistry and fluorescent in situ hybridization (FISH) have also led to a renewed interest in analysis of spermatogenesis on testicular biopsy. A precise “testicular phenotype” must now be established to propose an aetiological diagnosis, and to determine the mechanisms and risks of nonobstructive azoospermia and severe oligozoospermia for the embryo. We systematically perform testicular histopathology and meiotic study for each patient undergoing testicular biopsy for ICSI. We first describe the histopathological lesions. Examination of the testicular biopsy specimen determines whether the lesion is focal or diffuse. If it is focal, the percentage of altered tubules, evaluated on 50 tubules, should be calculated. Quantitative evaluation of seminiferous epithelium and a qualitative study of cell morphology must also be performed. There are four frequent lesion patterns: 1-Sertoli-cell-only syndrome; 2-tubular hyalinisation; 3-diffuse lesions in spermatogenesis; 4-mixed atrophy. However, the reliability of interpretation of testicular histology presents certain limitations, as no standard method of analysis of testicular biopsies has been defined and there is a marked variability in the histologist’s capacity to recognize the various histological patterns. Meiotic study is performed on the cell suspension remaining after ICSI, which contains immature germ cells. New methods using immunocytochemistry have replaced older methods. The panel of antibodies which detect individual protein components at different stages of meiosis provides a valuable tool for the detection and interpretation of abnormal meiotic profiles. We performed meiotic studies on 41 patients and 13 controls after Giemsa staining, and synaptonemal complexes (SC) from nine of these patients and one control were immunostained with a polyclonal antibody which recognizes the COR1/SCP3 protein of the lateral element of the SC. Nineteen of the patients presented obstructive infertility (O) and 22 presented nonobstructive infertility (NO). We showed that the rate of asynaptic nuclei from the NO group (25.4%) was significantly higher than that of the O group (9.8%) and the controls (9.8%). Two patients of the NO group had a high percentage of asynaptic nuclei (86% and 91.8%), which could arise from a primary meiotic defect. One of these patients had an AZFc microdeletion. The meiotic study in a patient with classical complete AZFb microdeletion revealed a high prevalence of early meiotic stages: leptotene, zygotene and early pachytene stages and marked impairment of the synaptic process in most spermatocytes. In the light of these findings, we conclude that the pachytene checkpoint is localized at the mid-pachytene stage in humans.     

Intérêt du dosage de l’inhibine B et de l’AMH dans le plasma séminal: étude préliminaire

Objectives

The aim of this study was to establish reference values for seminal inhibin B and AMH concentrations in patients with normal and abnormal sperm parameters. Preliminary analysis was performed to evaluate the predictive value of these markers for retrieving testicular sperm in non-obstructive azoospermic men.

Methods

Seminal inhibin B and AMH concentrations were assayed by an enzyme-linked immunoassay in three groups of men: 47 patients with normal sperm parameters, 28 oligospermic men and 68 patients with azoospermia.

Results

Inhibin B and AMH concentrations varied considerably in the three groups, but were significantly higher in normospermic men (inhibin B: 714.36±522.66 ng/l, AMH: 97.08±135.15 pmol/l) than in oligospermic men (inhibin B: 417.5±386.9 ng/l, AMH: 62.02±93.33 pmol/l) and azoospermic men (59.61±2.65 ng/l et 13.12±31.94 pmol/l, respectively) (p<0.001). A significant correlation (p=0.0054) was observed between seminal inhibin B concentration and sperm production. Testicular biopsy allowed sperm retrieval in 11 out of 21 patients (52.3%). The predictive value of seminal inhibin B was analyzed using receiver operating characteristics (ROC) curve analysis. The best discriminating inhibin B concentration was 30 ng/l with an area under the curve (AUC) of 0.63.

Conclusion

This study confirms the correlation between seminal inhibin B and AMH concentrations and spermatogenesis. However, the significance of these two markers as predictors of the presence of testicular sperm in men with non-obstructive azoospermia is limited. This analysis shows that AMH and inhibin B, either alone or in combination with serum FSH, fail to predict the presence of sperm in men with non-obstructive azoospermia undergoing testicular sperm extraction.     

Le MorphoTEP au FDG est un examen utile dans les cancers différenciés de la thyroïde avec élévation des anticorps antithyroglobuline

AimAssessment of the clinical impact of a PET/CT with FDG for the follow-up of differentiated thyroid cancer (DTC) with rising or positive thyroglobulin autoantibodies (AbTg) level and negative or inconclusive conventional imaging work-up.MethodologyThis retrospective study involves 15 patients seen in follow-up with confirmed DTC primarily treated with total thyroidectomy and Iodine-131. Patients presenting increased AbTg and a negative or non informative conventional workout were included. The results of the PET/CT were correlated with histology and/or clinical follow-up. The clinical impact was determined on a change of intention to treat, which was decided upon in multidisciplinary meetings, based on the PET/CT result.ResultsWe observed 10 true positive exams confirmed via histology in seven patients and via clinical follow-up in three on the average 33 months (20–53 months), three real negative exams with negative follow up of on the average 39.5 months (30–47 months), one false positive and one false negative. The intention to treat was modified in 73.3 % (11/15 patients). PET/CT showed sensitivity, specificity, positive predictive value, negative predictive value and accurancy of 91, 75, 90, 75, 86.6% respectively. There was a large and comparable dispersion of the AbTg values in both the true positive and the true negative groups, the kinetic of AbTg evolution could have a predictive value of a positive PET.Discussion/ConclusionPET/CT with FDG seems to be very useful in the therapeutic management of DTC in the case of AbTg increased or positive, in particular for the patients with N1 in the initial staging. Further studies are suggested to confirm the very promising negative predictive value and specificity of this exam in a larger number of patients.     

Prise en charge de l’infécondité dans les troubles de l’éjaculation: avis conjoints de l’andrologue, du biologiste et du gynécologue

It is estimated that eighty percent of men who present ejaculatory disorders would like to procreate but only 5–10% from them can do it. Ejaculation can be achieved by assisted-techniques used in association with pharmacological treatment. In cases of failure of ejaculation and azoospermia, epididymal and testicular chirurgical sperm extraction allows obtaining spermatozoa. Less numerous than those obtained in ejaculated sperm, these chirurgical spermatozoa offer the advantage to be not infected by bacteria and by seminal plasma. The quality of sperm is evaluated by conventional spermiologic methods and it is important to analyze presence of spermatozoa in the urine together with that in ejaculated sperm. In ejaculatory disorders, the quality of sperm is often impaired and the mobility and vitality of spermatozoa are abnormal. Numerous bacteria and leucocytes are also present. These changes seem to be related to many factors located in the seminal plasma rather than central and testicular damages. As in fertile and infertile man, cryopreservation causes a decrease in conventional variables. However, taking into account the difficulty to obtain sperm, all patients with ejaculatory disorders would benefit from semen cryopreservation. In order to achieved successful pregnancy, several fertility treatment are available: home insemination with semen obtained by vibroejaculation, intrauterine insemination, in vitro fecondation, or intracytoplasmic sperm injection. Counselling couples undergoing such treatment program needs coordinated efforts of different specialities, which may involve andrology, biology and gynaecology.