PubMed Health⌕ Search

Biomedical subjects

J Van Limborgh

Publications and source records attributed to J Van Limborgh.

7 recordsLinked to original sources
PubMed1983

Developmental deficiencies of the upper facial skeleton due to partial elimination of mesencephalic neural crest cells in the chick embryo.

With the aim to test the hypothesis that cells derived from the mesencephalic portion of the neural crest, are involved in the process of differentiation of various upper facial bones, in 41 chick embryos of the 6-somite stage (approx. 26 hours of incubation) the anterior and middle thirds of this part of the neural crest were partially eliminated by micro-laser irradiation, either unilaterally or bilaterally. Of the 14 embryos sacrificed at the age of 12 days, a number of 6 proved to have developed harelip and/or cleft palate conditions. In these embryos, in addition a reduction or absence of the maxillary, palatal, jugale and quadrato-jugale was observed. On the contrary, other facial bones as well as the first and second branchial arch cartilages proved to have developed normally. From these results the conclusion may be drawn that (a sufficient number of) cells from the anterior and middle thirds of the mesencephalic neural crest are indispensable for a normal differentiation of the maxillary, palatal, jugale and quadrato-jugale.

Animals↗
PubMed1976

The influence of propanediol-1,3 on the development of the legs, wings and lower beak of the chick embryo.

In seven series of 31-34 chick embryos each, the influence of the position of the egg during incubation and of the administration of 0.05 ml propanediol-1,3 on the 5th day of incubation on the development and growth of the limbs and beak were studied. Isotonic saline injected embryos served as controls. The embryos were sacrificed at the age of 15 days. Incubation of the egg in a vertical position, with the air chamber pointing upward, proved to result in a slight, through significant reduction in the length of the limbs and beak. Propanediol was highly toxic if injected in the immediate vicinity of the embryo. If injected at some distance from the embryo, either into the air chamber or into the yolk, the agent proved to be teratogenic: measurements showed a considerable retardation of the longitudinal growth of the limbs and beak, the latter being a parrot beak in 60 per cent of the cases, whereas both the tibia and the metatarsals were, moreover, bent posteriorward. Histological studies of the tibia showed an underdevelopment of the periosteal bone collar and, at the angle of the bone, a replacement of the posterior part of this collar by endochondral bone trabeculae. The abnormalities observed are dissimilar to those demonstrated in hereditary congenital chondrodystrophy and in micromelic conditions induced by insulin or sulfonamides.

Animals↗
PubMedDate not supplied

[Anatomy of the ano-rectal region].

Following a survey of the anatomical characteristics of the rectum and the posterior part of the pelvic floor, a description is given of the fibrous sheath enveloping the rectum, and of the fibrous leaves and septa which traverse the adipose tissue of the subperitoneal space and the ischiorectal fossa. These fibrous structures contain the blood vessels, the lymphatics and the nerves, the distribution of which is described in detail. The fibrous structures, in which many smooth muscle fibres are present, not only enclose the vessels and nerves but also form the suspensory apparatus of the rectum.

Anal Canal↗