Archives d'anatomie, d'histologie et d'embryologie normales et experimentales最新文献

Exposure of the fish to a long photoperiod (16L/8D) during the prespawning period accentuates the development of the ovary and increases the secretory activity of the pituitary gonadotrophs (GtH cells). A short photoperiod (8L/16D) or total darkness brings about follicular atresia of the vitellogenic oocytes and inhibits secretory activity of the GtH cells. Both the vitellogenesis and the GtH cell activity are restored in the fish exposed to short photoperiod if it is followed by a long photoperiod. Results indicate that the photoperiod plays a major role in controlling the reproductive activity in the teleost, Puntius sarana.

The present study assessed the number and diameter of myelinated fibers in the communicating branch between the hypoglossal and lingual nerves in man, with a view toward correlating their diameters with possible functions. In four cases, a mean of 806 (SD: 227 - minimum: 637 - maximum: 1127) myelinated fibers were counted in the communicating branch. Diameters ranged between 1 and 17 microns, and the frequency distribution was represented by a bimodal curve with peaks at 3-5 microns.

The cartilage model of the rat's patella constitutes a formation susceptible of inducing ossification, following its transplantation in a variety of sites (muscle, thyroïd, testis, ovary, anterior chamber of the eye, etc.), including those considered inappropriate in other experiments of induced ossification (liver, kidney). So we have an experimental model allowing the influence on the osteogenesis of various factors, local or general, natural or experimental, to be studied. Ossification occurs in this model only in cases of histocompatibility between donor and recipient. It is constant after autotransplantation or isotransplantation. It is never seen after heterotransplantation. In cases of homotransplantation its frequency varies: this is not influenced by the technical conditions of implantation but by tissue compatibility and the age of the animals giving and receiving. A private perichondrium cartilage retains its osteogenic potency. A cartilage killed by alcohol or cold no longer demonstrates its osteoformative capacities, even when put into contact with a living cartilage. Our findings are difficult to reconcile with the hypotheses invoking the osteogenic potency of the periosteum, or the intervention of substances either inducing osteoformation or inhibiting vascular invasion, for the explanation of endochondral ossification. However, they lead one to the opinion that chondrocytes play an active role in its release.

A histological study of the spleen in 30 human embryos in O'Rahilly's stages 17-23 revealed that the splenic anlage is composed of mesenchymal elements. Furthermore, the spleen is formed by a cytoreticulum containing a number of cells similar in appearance to lymphoid elements. No evidence of a celomocapsular separation is seen in this period.

When printing came into being, Strasbourg played a crucial role in the dissemination of the knowledge on anatomy, especially with the publication of Brunschwig's famous treatise on surgery in 1497. The first official human dissection in Strasbourg was performed in 1517. The teaching of medicine really began with the establishment of the Academy in 1566, but it was only in 1652 that a specific chair was created for anatomy. The first anatomical theatre was opened in 1670 in a secularized church contiguous to the city hospital. Until 1708, the teaching of anatomy is combined with that of botany; it was only from this date that anatomy was to be associated with surgery, and such was the case until the French Revolution. During the nineteenth century an impressive museum of anatomy was gradually established in Strasbourg. In 1872, after the annexation of Alsace, when the new german university was created, normal and pathological anatomy were separated and each chair attached to a particular institute. The building housing the institutes of normal and pathological anatomy was inaugurated in 1877 and is still used today. In 1919, when the Faculty of medicine was reorganized after Alsace was restored to France, histology and embryology were definitively separated from anatomy. Many famous anatomists worked in Strasbourg, among whom are to be found: J. G. von Andernach (1497-1574), T. Lauth (1758-1826), F. D. Reisseissen (1773-1828), J. F. Lobstein (1777-1835), E. A. Lauth (1803-1837), E. Küss (1815-1871), E. Koeberlé (1828-1915), E. Beaunis (1830-1921), H. D. Bouchard (1833-1899), J. G. Joessel (1838-1892), W. Waldeyer (1836-1921), G. Schwalbe (1844-1916), W. Pfitzner (1853-1903), F. Keibel (1861-1929), A. Forster (1878-1957) and Ph. Bellocq (1888-1962).

Reconstructed median sections of staged human embryos were prepared to provide fundamental insight into the developing human brain. 1. At its first appearance as neural plate at stage 8 and even better visible at stages 9 and 10, the rostral end of the CNS is at the chiasmatic plate, that is, at the rostral end of the diencephalon. The telencephalon is a later acquisition. 2. The main parts, already visible in the neural plate, become arranged as neuromeres as the neural tube develops. The neuromeres, defined by definite morphological features, are transversely arranged originally. As morphological entities they are visible longest in the rhombencephalon (up to stages 17-18). 3. The initially uniformly thick walls at stages 12 and 13 develop thickenings: medial and lateral eminences in the forebrain constitute parts of the corpus striatum. The hippocampus forms as a rostrocaudally growing C-shaped thickening in the medial wall of the cerebral hemisphere. The ventricular bulge develops in the alar areas of Rh 1 and the isthmic segment, and develops into the corpus cerebelli. 4. Internal sulci are important landmarks. The sulcus limitans separates alar and basal plates in the rhombencephalon and mesencephalon, but it does not continue into the forebrain. The hypothalamic sulcus separates the hypothalamus from the thalamus (epi-, dorsal, and ventral thalami); the sulcus circularis separates the olfactory bulb from the olfactory tubercle. 5. The embryonic brain develops from approximately day 18 to day 57, i.e., during a period of 5 1/2 weeks. It progresses from a neural plate to a highly complicated, almost spherical organ, parts of which, to judge from their morphology, should be capable of functional competence.

Melatonin (aMT) implantation during testicular inactive phase (January-March) brought an early initiation of testicular development in Perdicula asiatica. However, during the recrudescence (March-May), active (April-June), and regressive (May-July-September) phases both aMT and 5-methoxytryptamine (MT) implantation had inhibited testicular weight and activity significantly. Subcutaneous injections of aMT, MT and 5-methoxytryptophol (ML) during morning (7.30 a.m.-8.00 a.m. and evening (4.30 p.m.-5.00 p.m.) could not bring about any significant effect on the weight or activity of the testes during the inactive (January-February) phase, while inhibited testicular weight and activity during the active (May-June) phase when administered in the morning as well as in the evening hours.

Topographic anatomy of the different parts of the corpus adiposum buccae is analyzed by coronal, transverse and sagittal sections. These sections are compared with those realized in the same planes by tomodensitometry and magnetic resonance. This comparison allows a better knowledge of the structures shown by imaging in the superficial and deep facial regions.

The microvascularization of the sternum of the child has been studied by a method of India ink injection and by histology. Extra-osseous vasculature includes vascular pedicles and sternal vascular networks. Vascular anterior and posterior pedicles issue from internal mammary vessels. Sternal anterior and posterior networks are disposed on the faces of the sternum and are divided in a superficial one and a deep one; both are included in the perichondrium. In newborns and in young infants, vascular structures looking like baskets are affixed to the deep sternal network. It is unlikely that they intervene in the constitution of the adult pattern of the sternal vasculature. The early complete development of sternal networks contrasts with the existence of evolutive characteristics of the intra-osseous vasculature. Intra-osseous vasculature includes the cartilage canal vessels and the vessels of the ossification centers. Cartilage canals are provided with an axial artery, issued from the deep sternal network, which produces short capillaries which continue in peripheral sinuses. Cartilage canals permit the penetration of perichondral tissue deep in the cartilage of the developing sternum, allowing the formation of the ossification center. The ossification center is vascularized by centrifugal arteries, issued from the cartilage canal artery, and disposed in a radiant pattern. They continue, through a conical progressive dilatation, into a sinusoid network, which presents a convergent disposition towards the center of the ossification point. Vascular events precede ossification. Hematopoietic development is consecutive to the vascular events too. The slenderness of vascular pedicles contrasts in neonates with the wide development of the sinusoid network. Adipose tissue is rare in the bone marrow sternum of the child. Secondary evolution of the ossification center vasculature permits its connections with the deep sternal vascular network, with adjacent cartilage canals, and with adjacent ossification centers. Progressively, the number and the importance of the peripheral pedicles of the ossification centers increase. Thus, a multiple and centripetal vascular provision takes the place of the initial, unique, centrifugal one. These modifications correspond to the transition from the vascular pattern of an expanding structure (the ossification center) to the one which is adapted to the full expression of its hematopoietic function.

Ovaries from control and hypophysectomized chick embryos were cultured in vitro, and oestradiol released into the culture medium was determined by radioimmunoassay. At all 4 stages investigated, i.e., 11, 13, 15 and 17 days, the ovary of hypophysectomized embryos secreted less oestradiol than the ovary of control embryos. However, per unit weight of ovary, oestradiol production was clearly less in hypophysectomized than in control embryos only at the stage of 11 days. It is concluded that the hypophysis plays a part in oestradiol secretion by the ovary in the 11-day-old chick embryo.