Utilisation des spermatozoïdes testiculaires en ICSI. Intérêt de la culture in vitro. Revue de la littérature

The number of ICSI cycles performed with testicular spermatozoa has increased dramatically over recent years. However, one of the technical limitations of this approach concerns the extremely reduced motility of testicular spermatozoa. However, increased sperm motility was observed after incubating testicular samples for several hours. Therefore, in order to improve ICSI success rates, several authors have tested the effect of previous in vitro culture. We present a review of the literature on this subject. In vitro culture does not appear to be very useful in cases of obstructive azoospermia, as, apart from possible sperm “maturation” during this culture phase, a high proportion of motile spermatozoa is usually already observed prior to in vitro culture. The benefits of in vitro culture appear to be greater in the case of non-obstructive azoospermia, as when spermatozoa are present on the biopsy, they are usually immobile. However, discordant results have been published: after in vitro culture, spermatozoa have been reported to be either motile or mostly dead. Regardless of the type of azoospermia, the best results are obtained after 3–4 days of in vitro culture. Addition of recombinant FSH to the culture medium also appears to be effective. Cryopreservation of testicular biopsies may also be associated with in vitro culture and the in vitro culture/freezing sequence appears to give better results than the freezing/in vitro culture sequence. Very few studies have reported the results of ICSI using frozen in vitro cultured spermatozoa, as most published studies concern fresh spermatozoa, used after 1–2 days of in vitro culture with satisfactory fertilization and pregnancy rates. In vitro culture of testicular spermatozoa may therefore constitute an interesting research approach to improve the results of ICSI when the number of spermatozoa and/or motility are very low. In addition, in vitro culture of testicular spermatozoa appears to be a good tool to study the mechanisms of acquisition of motility, which are still poorly understood.     

Indications de la recherche des anticorps anti-spermatozoïdes

The clinical significance of antisperm antibodies (ASA) is highly controversial. A significant percentage of infertile men and women present immunity to spermatozoa, suggesting that ASA may interfere with the fertilizing capacity. ASA can act negatively on sperm parameters, sperm-cervical mucus interaction, gamete fusion and possibly also on the first step of embryonic development. ASA are present in approximately 2.8% to 26% of the male population and 0.2% to 1.6% of women. The pathogenesis of immunity to spermatozoa had not been fully elucidated: breakdown of normal protective mechanisms, i.e. blood-testis barrier, or epithelial barrier in women, and other mechanisms of immunological sperm tolerance, such as regulation of suppressor T lymphocytes. The indication for antisperm antibody testing is based on clinical and laboratory findings of infertile patients. In men, indictions for ASA testing include a history of genital disease, surgery for genital abnormalities, vasectomy, obstruction or injuries of the male genital tract, infection of accessory glands, long-standing infertility, alteration of semen parameters (agglutination, motility), mucus penetration, and reduced fertilizing capacity in IVF. In many cases, no etiological cause of autoimmunity is found and a genetic predisposition has been suggested. A majority of women do not develop antisperm antibodies, despite repeated contact with spermatozoa during their sexual life. Upper genital tract infection is the main cause of isoimmunization in females, although sexual practices, endometriosis, surgery for cervical neoplasia, recurrent spontaneous abortion and long-term infertility may also be involved. Sperm-cervical mucus impairment is the most obvious effect of immunization in women associated with IVF failure. Autoantibodies are frequently associated with antisperm antibodies. One of the consequences of the success of ICSI has been a decreased research effort to further the understanding of the origin and relevance of antisperm antibodies and specific antibody-antigen interactions. A better understanding of the natural history of immunological infertility would be useful for patient conseiling and to develop the most effective, efficient and safest management strategies. Such data could also be useful for the development of new tests and immunological methods of male contraception.     

Perspectives de l’analyse de la mobilité des spermatozoïdes

Several studies have shown a good correlation between sperm motility and fertility though the microscopic evaluation of the percentage of motile sperm is highly subjective by nature. Therefore in the last decade, various objectives methods have been proposed to overcome this problem. Two types of methods were developed: The methods based on the analysis of images obtained by microphotography, microcinematography and microvideography and the global, undirect methods based on physical principles. Several systems based on video and image analysis (Computer Aided Sperm Analysis, CASA) have been developed and are used in numerous laboratories of reproductive biology. CASA technology offers the possibility to analyse some characteristics of sperm motion which are related to the fertilization potential and to develop new parameters related to some important aspects of sperm behavior such as hyperactivation. However, there is a large amount of interactions between the operator and the CASA machine. CASA instruments are not “ready-to-use” robots: the reliability of CASA depends largely on the expertise and training of the user and the application of standardized procedures and quality control schemes. By contrast, there is only minimal interaction between the operator and the Sperm Quality Anlyser which is a new device measuring and index of sperm motility highly correlated to the concentration of progressively motile sperm. The device uses light passed through a small sample of semen introduced in a capillary tube to detect variations in optical density that result from moving particles. The reproducibility of the measurements is excellent, the device is easy to use and this is a potentially useful tool for field-work studies. Further investigations of this device in the managment of male infertility is warranted. Finally, both types of objectives approaches are complementary to the conventional analysis of sperm motility and they will not replace it. Standardized procedures have been proposed by the World Health Organization for the subjective evaluation of sperm motility. Such procedures are very useful to reduce significantly the intra- and interlaboratory variations but internal and external quality controls schemes indicate that they are not sufficient to achieve acceptable levels of variation and regular quality controls followed by the definition and the application of corrective procedures are required.     

Controle de la multiplication et de la polyploïdie des hepatocytes du rat

Résumé L'injection de substances irritantes de nature chimique variée perturbe les mécanismes qui contrÔlent la multiplication des hépatocytes du rat.Les très jeunes rats réagissent de faÇon intense et reproductible. 15 heures après l'injection il se produit une augmentation brève et intense du nombre des cellules entrant en phase S de sorte que les divisions cellulaires, qui normalement auraient été réparties sur les 30 ou 40 prochaines heures, débutent en l'espace de 2 heures seulement. La croissance hépatique a pris une importante avance qui est suivie par une période de diminution du nombre des mitoses due à une rétroaction inhibitrice.La réaction des rats plus âgés met en évidence un mécanisme inhibiteur permanent qui entraÎne une réponse moins intense et moins régulière.La production d'hépatocytes binucléés et polyploÏdes parait liée à ce mécanisme inhibiteur.La régularité et la sensibilité des réactions des très jeunes rats en fait un matériel de choix pour l'étude des mécanismes régulateurs de la croissance hépatique.

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Control of multiplication and polyploidy of rat hepatocytesA study of the perturbations of physiological regulation induced by injection of irritants

Summary The injection of irritating substances of various chemical nature disturbs the mechanisms regulating the multiplication of rat hepatocytes.The reaction of baby rats is intense and reproducible. It results, 15 hours after the injection, in an increase of the number of cells entering the S phase, so that practically all the divisions which would normally have been scattered over 36 hours are initiated within 2 hours. This burst of synchronized mitosis corresponding to a 36 hours advance in the hepatic growth is followed by a decrease of mitoses due to a feed-back inhibition.The reaction of older rats brings to evidence a permanent inhibitory mechanism that results in a less regular and intensive response.The production of binucleated and polyploÏd hepatocytes seems to be correlated to this inhibitory mechanism.The regularity and sensivity of the baby rat reactions make them a choice material for the study of hepatic growth.

     

Contribution à l'etude des thecamoebiens de la Province de Buenos Aires

Résumé La faune des Thécamoebiens fut étudiée dans deux étangs (La Brava et De los Padres) situe dans la Province de Buenos Aires (Argentina). Le nombre d'espèces trouvé en tout a été de 14, quelques-unes desquelles représentées par de différentes formae. Une nouvelle forma Centropyxis compressa (Cushman), forma brava n.f. a été trouvée et décrite, et une espèce de Pontigulasia a été proposée en nomenclatura aperta.

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Summary The Thecamoebiens of two lakes (La Brava and de los Padres) located in the Province of Buenos Aires (Argentina) were studied. The total number of species found is 14, several of them are represented by various formae. A new forma was found and described, namely Centropyxis compressa (Cushman), forma brava n.f. and one species of Pontigulasia was put in nomenclatura aperta.

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Departamento de Ciencias Biologicas, Facultad de Ciencias Exactas y Naturales Universidad de Buenos Aires     

Contribution à la connaissance des fungi keratinophiles de l'ouest de la France V. Étude au microscope électronique à balayage

Résumé La recherche des Fungi kératinophiles dans 301 prélèvements de sol de la Loire-Atlantique a permis de trouver une fois sur troisArthroderma uncinatum. A. curreyi est assez abondant.Nannizzia cajetani, A. quadrifidum etA. tuberculatum ont été également assez souvent mis en évidence.Chrysosporium keratinophilum semble rare. Plus rares également sont les espèces plus spécialement pathogènes:A. benhamiae, N. fulva etN. incurvata.L'étude au microscope électronique à balayage permet de séparer et définir différentes espèces par l'observation des ornementations: verrues, granules, érosions planes, crêtes. C'est ainsi que nous pouvons confirmer la séparation des deux espècesN. fulva etN. incurvata.     

Influence de la nature et de l'abondance des proies sur l'augmentation des effectifs de deux coccinelles prédatrices de la cochenille du manioc au Congo

Résumé Les variations d'abondance des 2 cochenillesPhenacoccus manihoti Matile-Ferrero etFerrisia virgata Cockerell et des 2 prédateurs CoccinellidaeHyperaspis senegalensis hottentotta Mulsant etExochomus flaviventris Mader sont étudiées dans une parcelle de manioc. La colonisation de cette dernière parE. flaviventris est précoce, en présence de faibles niveaux numériques des 2 proies, mais avec une dominance deF. virgata; celle d'H. s. hottentotta intervient un mois plus tard en relation semble-t-il avec la présence d'une population deP. manihoti abondante et jeune. Nos observations font ressortir une dynamique des populations propre à chaque espèce de coccinelle, conditionnée par l'abondance de l'une ou l'autre des proies, la structure des colonies de chaque cochenille et les conditions climatiques (température) qui interviennent en synergie. Ainsi, la réponse numérique deH. s. hottentotta, plus forte que celle d'E. flaviventris, semble en relation plus étroite avecP. manihoti. PourE. flaviventris il appara?t difficile de séparer ce qui revient à chaque espèce de cochenille:F. virgata joue sans doute un r?le important pour son implantation dans les champs, puis sa raréfaction, mais c'est probablementP. manihoti qui permet l'augmentation de ses effectifs.      

Étude expérimentale des variations de la teneur en eau au cours de la déshydratation et de la réhydratation chez la Fougère:Notochlaena vellea R. Br.

Experimental Study of changes in water content during dehydration and rehydration of the Fern: Notochlaena vellea R. Br.—This study takes place after studies made on otherPolypodiaceen Ferns. We have shown that, in these ferns, the survival duration was longer for the subterranean organs than for aerial ones. The problem was to show that this difference is due to a lower dehydration of the subterranean tissues. As far as we looked at the total water deficiency, we did not find any significant difference between the leaves and the meristematic parts of the subterranean organs: the main difference is the rate of rehydration which is higher in subterranean parts.     

Étude de l'effet de la température sur la division des cellules séparées de feuilles deCalystegia sepium (L.) R.Br.

Cells mechanically isolated from homogenized leaves ofC. sepium dividein vitro. The rate of cell division is strongly influenced by temperature with the optimum between 31 and 34 °C. The rate of cell division increases proportionally with a rise in temperature up to 31 °C and is accompanied by a reduction in the length of the preparatory phase of the division. A supraoptimal temperature (40 °C) inhibits or stops the cell division which can be restored provided that the cells are transferred to 31 °C. If the preparatory phase to the commencement of cell division is accomplished at 17 °C the cells then exposed to 31 °C divide more rapidly than if they are exposed directly to 31 °C.     

Influence de la densité de population larvaire sur la taille des adultes,la durée de développement et la fréquence de la diapause chezPteromalus puparum L. [Hym., Chalcidien]

Summary The parasitoid waspPteromalus puparum was reared for many generations under controlled laboratory conditions: larval development in diapausing pupae ofPieris brassicae, 14 hours photoperiod, temperature of 21 °C or 25 °C. The fluctuations in the density of population appear to be the main source of variation for larval development. An increase in the number of larvae living in the same host pupa results in a decrease of adult size, a reduction of developmental time and a diminution of incidence of larval diapause. According to these results, it appears that a high population density hastens the occurrence of metamorphosis and makes it easier. It is suggested that various nervous stimulations, such as food shortage and interactions between larvae, may induce the onset of neurosecretion by the brain.      

Consanguinité et effectifs de la population des communes

Summary In a previous paper, we have used the density of the population as a sort of measure of the unknown size n of the isolates in Dahlberg's model, and shown an inverse relation between the coefficient of inbreeding and the density of the arrondissements. In the present paper, as the considered communes are smaller territorial subdivisions than arrondissements, we used, instead of the density, the population size of the communes. The results are even more eloquent as before: the inbreeding coefficients are large when the observed population size is small; the relative importance of second cousin marriages (233) versus cousin marriages (222) is greater in the latest period considered. The basic data have been collected for each commune in Belgium by Centre National de Radiobiologie et de Génétique.     

La formation des isozymes de l' α-amylase durant la germination de l'orge

Summary The -amylase formed in germinating barley has been separated into six isozymes by means of polyacrylamide gel electrophoresis. These isozymes do not appear from the beginning of germination but are formed gradually so that after six days all six -amylase isozymes are present.When gibberellic acid is added to the culture medium the production of the -amylase isozymes is accelerated considerably, whereas the addition of kinetin has no influence at all on the formation of the -amylase isozymes.The -amylase induced by gibberellic acid in the aleurone layers of isolated barley endosperms apparently consists of five isozymes, a number that does not change upon further incubation.The action of phytohormones such as gibberellic acid and kinetin on the formation of -amylase and its isozymes during the germination of barley is discussed.     

Recherche d'antigènes de groupe chez des rickettsies de la tribu desWolbachiae par la technique d'agglutination des corps élémentaires

Résumé Les relations antigéniques entre einq rickettsies pathogènes aux Invertébrés sont étudiées par agglutination. Cette comparaison met en évidence que le genreRickettsiella ne constitue pas au point de vue immunologique un ensemble homogène. On définit deux groupes sérologiques distincts:R. melolonthae, R. tipulae etR. cetonidarum appartiennent au groupe I; le groupe II est actuellement consitué parR. grylli etR. armadillidii.

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Summary The antigenic relation between five rickettsiae pathogenic to Invertebrates have been studied by agglutination. This comparison shows that the genusRickettsiella does not form and homogeneous group from an immunological point of view. Two separate serological groups are defined:R. melolonthae, R. tipulae andR. cetonidarum belong to the Ist group;grylli andR. armadillidii are forming the IInd group now.

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Ce travail a été réalisé en partie dans le cadre d'une convention D.R.M.E.