Les prélèvements testiculaires dans les azoospermies sécrétoires: indications et bilan andrologique

The management of patients with nonobstructive azoospermia must not be limited to testicular biopsy. A complete andrological assessment must be performed to adapt treatment to each patient, in order to:

-avoid testicular biopsy by screening for “azoospermia-like” syndromes and treat any etiological factors (pituitary hypogonadism, varicoceles, cryptorchidism), and concomitant aggravating factors (spermatic cord infection, obstructive factor of the epididymis or vas deferens).

-screen for clinical or subclinical testicular tumors and demonstrate genetic anomalies involving risks for the offspring.

-establish a prognosis regarding the possible use of medically-assisted reproduction by ICSI (intracytoplasmic sperm injection) with testicular spermatozoa.

     

Essais de cultures de tissus de Lépidoptères sur matières plastiques

Zusammenfassung Es wird auf die M?glichkeit hingewiesen, plastische Kunststoffe für die Kultur von Insektengeweben zu benutzen. Die Entwicklung der Zellen auf Polyvinylchlorid-Folien ist ebenso gut wie auf Glas; es lassen sich auch fixierte und gef?rbte Pr?parate herstellen, und die Kunststoff-Folien lassen sich mit Kanadabalsam zusammenkleben und aufbewahren. Die Vorteile von Kunststoff-Gef?ssen werden hervorgehoben.      

Les problèmes de systématique dans les recherches écologiques sur les insectes entomophages

Summary The first step in ecological studies of entomophagous insects is the collection of the different species associated to a given host in a given biotope. Many species are frequently encountered and their identification is often impossible or limited to the name of the genus, because detailed publications on systematics are not available and there are not enough specialised taxonomists. The needs for a precise identification increase when the study of the role of natural enemies is undertaken; the maximum complexity being reached when biological control methods are to be developped. It is then necessary to establish differences between biological races, sibling species etc. A striking example of these kind of difficulties is given by the biological control of California red scale. Progress in the field of systematics of entomophagous insects is only possible if we have a better knowledge of their biological and ecological requirements. Some examples are given of recent results obtained by different study groups of the C.I.L.B.: O. concolor bred fromC. capitata and fromD. oleae have been recognized as a single species, the adaptability of which is now studied-stress has been put on characteristics and efficiency of different strains ofP. perniciosi. Specificity and geographical distribution of egg parasites of genusOoencyrtus are reviewed in the mediterranan area... A close cooperation is to be maintained between workers in the fields of systematics and ecology, the contribution of C.I.L.B. will be of a great value.      

Premières observations sur les sphaignes des Alpes-de-Haute-Provence

Sphagnum mosses have been observed for the first time in the Alpes-de-Haute-Provence French department. The four species discovered are confined to Annot sandstone siliceous bedrock formations scattered amongst dominating calcareous bedrock in the area. Both Sphagnum nemoreum and Sphagnum teres are quite frequent in the French Alps while Sphagnum flexuosum and Sphagnum angustifolium on the contrary are rare peat mosses in this chain. Local edaphic and climatic conditions might be responsible for the reduced number of sites discovered. All Sphagnum sites are briefly described. One of them a true peatland is of particular interest and deserves protection.     

Recherches morphologiques et physiologiques sur les glandes annexes mâles des orthoptères

Résumé Deux modes d'associations des spermatozoïdes sont décrits dans l'ordre des Orthoptères.Chez les Tettigonides (Ensifères), les spermatozoïdes mûrs s'accrochent mécaniquement, les uns aux autres, par leurs acrosomes. Les faisceaux, ainsi formés, comprennent une dizaine de cellules sexuelles. Dans les voies déférentes, des sécrétions mucopolysaccharidiques, élaborées par les cellules glandulaires de la paroi et rejetées dans la lumière, enrobent le faisceau spermatique d'un manchon structuré. Le spermatodesme est alors constitué.Chez les Acridiens (Caelifères), le spermatodesme se forme dans le follicule testiculaire, avant la fin de la spermiogenèse. Les spermatides pénètrent dans le cytoplasme d'une cellule nourricière; celle-ci élabore une secrétion dense entourant les têtes des cellules sexuelles. A la maturité, la sécrétion se détache progressivement de la cellule nourricière et forme la coiffe d'un faisceau spermatique qui groupe environ deux cent cellules. Cette coiffe non structurée et opaque aux électrons est de nature mucoprotéique et contient des enzymes.Les deux formations décrites diffèrent donc à la fois par leur origine, leur structure et leur nature chimique. Leurs rôles physiologiques possibles sont envisagés.

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On the types of sperm association in orthoptera

Summary Two types of sperm associations are described in Orthoptera.In Tettigonids (Ensifera), the mature spermatozoa are hooked together by their acrosomes. The bundles so formed are composed of about ten spermatozoa. In the genital ducts, mucopolysaccharidic secretions, elaborated by the glandular cells of the walls, and ejected in the lumen, form a muff around the bundle: The spermatodesm is then constituted.In Acridids (Caelifera), the spermatodesm is produced earlier, before the end of spermiogenesis, in testicular follicles. The spermatids enter the cytoplasm of a nurse cell; the latter elaborates a secretion which coats the sperms' heads. When maturity occurs, the secretion detaches from the nurse cell and makes up the cap of a sperm bundle which groups about 200 cells. This cap is a dense structureless substance, mucoproteic in nature and containing enzymes.The two types of formations described differ in origin, structure and chemical nature. Their physiological roles are discussed.

     

L’agriculture africaine face aux changements globaux : recherches et innovations basées sur les sciences de l’écologie

In the context of environmental and socio-economic changes, the agriculture of Sub-Saharan African countries will have to ensure food security of the population, while reducing its environmental footprint. The biophysical and social systems of agricultural production are complex. Innovative agricultural practices will be based on an intensification of ecological processes that determine the functioning of the soil–plant system, farmers’ fields and agro-ecosystems. This ecological engineering approach is useful to take up the challenge of Sub-Saharan agricultures in the future, as shown in researches conducted by IESOL International Joint Lab “Intensification of agricultural soils in West Africa” (ISRA, UCAD, TU, OU, INERA, IRD).     

Recherches sur les efflorescences des phéophycées

Resume L'analyse radiocristallographique de diverses Phéophycées a révélé la nature des substances insolubilisées a l'intérieur du thalle et formant des elorescences au cours de la dessiccation.Le D-mannitol cristallise essentiellement sous la forme monoclinique, les variétés et ß orthorhombiques apparaissent plus rarement toujours en faibles quantités.L'examen röntgénographique et les analyses quantitatives montrent que les chlorures de sodium et de potassium se déposent à la surface en proportions qui reflètent les variations de composition du thalle. Les valeurs du rapport Na⁺/K⁺ sont caractéristiques des diverses familles.

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Summary An X-Rays analysis of various Phaeophyceae has revealed the nature of substances inside the thallus becoming insoluble and efflorescing during drying.D-Mannitol cristallizes essentially in monoclinic form, and ß orthorhombic varieties appear less frequently.Röntgenographic examination and quantitative analysis show sodium and potassium chlorides forming a surface deposit in proportions correlated with the variations of the chemical composition of the thallus. The values of the ratio Na⁺/K⁺ are typical of the various algal families.

     

Étude de l'un des caractères physiques essentiels des signaux acoustiques réactogènes artificiels sur les orthoptères et d'autres groupes d'insectes

Summary It can be shown that with Orthoptera (Acrididæ orTettigoniidæ) phonoreactions can be evoked by synthetic acoustic signals of a pure frequency. For reactions to be evoked it is necessary for the signals to contain at least one transient (transient is a term of acoustics, used for rapid changes of the intensity of an acoustic signal) of great amplitude either at the beginning or at the end. The phonoreaction can be evoked by a very short signal—a few milliseconds in duration—and independently, of a frequency limit to suit each type (500–20000 Hz for theAcrididæ, 50–80000 Hz for theTettigoniidæ). The intensity of the signal should be higher than that of a natural signal (10–20 dB). The phonoreactions described can be diverse: phonocinesis, phonotaxie.The physical examination of the different acoustic signals, described in the literature as the provokers of reactions in other groups of insects, shows that these signals belong to the type described by the author, and all contain at least one transient of great amplitude. Such phonoreactions to synthetic signals, the control of escapereactions by the individual seem to be dependent upon the mechanism of differential sensibility, as defined byLoeb for light.

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Zusammenfassung Man kann zeigen, daß bei den Orthopteren (Acrididæ oderTettigonidæ) durch künstliche akustische Signale reiner Frequenzen Schallreaktionen hervorgerufen werden. Damit die Signale Reaktionen hervorrufen, ist es notwendig, daß sie mindestens einen transitoire de grande amplitude (=schr rascher und großer Wechsel der Intensität des Schallsignals)enthalten müssen, der entweder am Anfang oder am Ende liegen kann. Die Schallreaktion kann hervorgerufen werden durch ein sehr kurz dauerndes Signal — in der Größenordnung von einigen Millisekunden — und unabhängig davon in einem für jede Art charakteristischen Frequenzbereich (500–20000 Hz für die ccri-didæ, 50–80 000. Hz für dieTettigonidæ). Die Intensität des Signals sollte höher als die der natürlichen sein (10–20 dB). Die beschriebenen Schallreaktionen können verschieden sein: Phonokinese, Phonotaxie.Die physikalische Untersuchung der akustischen Signale, auf die in der Literatur als Reaktions-Auslöser für andere Insekten-Gruppen hingewiesen ist, zeigt, daß diese Signale dem vom Autor beschriebenen Typentsprechen und alle wenigstens einen transitoire von großer Amplitude enthalten. Die Schallreaktionen auf künstliche Signale, deren Kontrolle dem Individuum entgeht, scheinen vom Mechanismus der differentiellen Sensibilität, wie er durchLoeb für das Licht definiert wurde, abhängig zu sein.

     

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.     

Recherches sur les rotifères des eaux saumâtres

Résumé Pour la première fois, les rotifères de la Camargue sont examinés. Des échantillons ont été pris aux environs de Salin de Badon, le long de la digue de mer et dans l'étang de Beauduc.Les 15 espèces trouvées sont nouvelles pour la région. Pour chacune d'elles, nous donnons l'écologie et la distribution dans l'eau saumâtre dans le monde entier.La plupart des espèces sont cosmopolites; une espèce est particulièrement intéressante, notamment Epiphanes mollis, dont c'est la première capture dans l'eau saumâtre de l'Éurope occidentale.

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Rijkuniversiteit Gent. Laboratorium voor Systematische Dierkunde.     

Rôle des organes pulsatiles thoraciques et du cœur pendant l'émergence et l'expansion des ailes des lépidoptères

Electrograms of the thoracic pulsatile organs and of the heart during emergence and expansion of the wings have been made. The mesotergal and metatergal organs function in a similar way: active periods are interrupted by short periods of rest, but the two organs contract with different but apparently independent rhythms. During emergence and expansion, the rate of contraction of the pulsatile organs increases twofold, and the resting periods disappear during the entire period of expansion of the wings. When the wings are removed or cut short, the activity of the pulsatile organs is inhibited.     

Évaluation des rythmes et des vitesses d’évolution chez les Mammifères

The natural selection proceeds to very different time paces according to the hierarchical level of the observations. Two methods are used by palaeontologists for reporting how fast is evolution through geological time: the taxonomical and the morphological rates of evolution. However, the interpretation and the understanding of these rates of evolution are not easy. So, there were and still are many debates, and even controversies, concerning the tempo of the history of life as depicted by fossils. Examples from European Palaeogene fossil mammals illustrate some aspects of this problem.