[Appearance of the branchial system in cervicofacial embryology]. / A propos de la notion d'appareil branchial en embryologie cervico-faciale.

The aortic arch, vascular component of the branchial segment, is considered as its determining element. This is only justified in the conception of a branchial primordium, although this has now been discarded. The direct objections against this theory of a vascular preeminence are presented. Therefore, a revision of cervicofacial morphogenesis (formations cranial to the mandibular arch) is mandatory, based on somitomeres, neural systematization, evidence obtained from heterograft experiments and genetics, allowing to recognize in the "branchial" organization its proper somatic participation. The repartition of elements deriving from the para-axial in the "branchial" segmentation suggests that both types of segmentation represent two coordinate expressions of a single process.

[Apropos of the "Lesson in anatomy"]. / A propos de la "Leçon d'anatomie".

Some striking features from the famous lesson of Prof. Tulp are presented: the implication of the spectator in the scene, the unity of the action exalted by the "chiaroscuro", the expression of the movement and of Tulp's personality. In addition, the probable scientific and philosophical underlying thoughts of Rembrandt are discussed having respect to historical data concerning Descartes and Constantin Huygens. The indications given by the lesson of Pr. Deyman about Rembrandt's conception of this subject and the evolution of his art, are then presented. Among the "Anatomy lessons" of the Dutch painting which have preceded and followed those by Rembrandt, the three having particular relevance to the Master are discussed, allowing to better appreciate his originality, his audaciousness and his mastery of his art.

[The concept of branchial apparatus and cervico-facial embryology]. / La notion d'appareil branchial et l'embryologie cervico-faciale.

The so-called "branchial" embryonic organization corresponds to a segmental disposition, for which a determining role of the aortic arch, vascular component of the constitutive unit of this organization, has never been disputed. This attitude is only justified by virtue of the conception of this organization as preparatory to a branchial primordium, although this initial conception, which raises major objections, has now been discarded. Moreover, direct objections against this theory of a vascular preeminence are presented. Therefore, a revision of cervico-facial morphogenesis (formations cranial to the mandibular arch) is mandatory, based on somitomeres, neural systematization, evidence obtained from heterograft experiments and genetics, allowing to recognize in the "branchial" organization its proper somatic participation. The repartition of elements deriving from the metameric segmentation in the "branchial" segmentation suggests that both types of segmentation represent two coordinate expressions of a single process. The primitive characters of the "branchial" segmentation (tendency to be total, paleontological data, cartilaginous skeleton) are suggestive for a peripheral and limited expression of the segmentation, which appears as an intermediary type between that of the invertebrates and that metameric segmentation which predominates in the para-axial region. In this perspective, the "embryonic branchial apparatus" represents a structural link between invertebrates and vertebrates. This type of segmentation applied to the "pharynx" of chordates has allowed the outgrowth of vertebrates, acting as a major key in their organization.

[The origins of embryology. Epistemologic and cultural viewpoints]. / Les origines de l'embryologie. Aperçus épistémologiques et culturels.

Embryology is exemplar from an epistemologic point of view, due to its close relation with philosophy as studying an immediately accessible link in the process of generation. It has evolved to its present form following the development of the microscopical techniques at the end of the 18th century, but remains close to the ancient approaches of generation. The roots of modern Embryology are still to be found in the presocratic philosophers, and the works of Aristotle represent a major step in its foundation. Embryology also had a prominent place in the reappraisal of Aristotle's work by Albertus Magnus in the middle ages, following the islamic influences. This reappraisal opened the way to the scientific movement of the Renaissance, when Leonardo da Vinci played an essential role, approaching the development of the human embryo. Embryology is therefore linked to the major influence exerted by Aristotle on occidental civilization, it has then a prominent place from a cultural point of view.

[Human cervico-facial morphogenesis. Evaluation of acquired data and current outlook. (Part 1: facial morphogenesis)]. / La morphogénèse cervico-faciale humaine. Bilan des données acquises et perspectives actuelles.

The embryonic development of the face has been studied in many reviews, this work purposes only to clear up some points which remain obscure concerning cervico-facial morphogenesis. In the first part of this study only the facial development, properly speaking, is considered, although it cannot be separate of cervical development to which a second study will be reserved. In the present study we recall the particular aspects of the neurulation in the cephalic area, then the establishment of the facial processes. Then we approach among other things the way to consider the maxillary process with regard to the other facial processes. After is considered constitution and natured of the prechordal plate which has been diversely explained. Finally, the modelling of the face is evocated, in which the dissociation between the olfactive and buccal spheres is pointed out, with the disparition of the muzzle, as it is established in the haplorhinae, a class of primates in which the human being is involved. This phenomenon raises different questions, in particular about the relation of this disposition with the nasoseptal center, the medial part of the nasodorsal center.

[Degeneration and regeneration of striated skeletal muscle fibers in Duchenne muscular dystrophy]. / Dégénérescence et régénération des fibres musculaires striées squelettiques dans la myopathie de Duchenne.

Like all other muscular dystrophies, Duchenne muscular dystrophy is characterized by the coexistence of degenerative lesions of the muscle fibers and of regenerative changes. The present study has been carried out in order to precise the degree of regeneration at different stages of the disease, by analyzing the expression of several markers of cell proliferation and of muscular differentiation. In the two affected foetuses of our series, the m. quadriceps is histologically normal, except for the absent expression of immunoreactive dystrophin. The quadriceps from the eight children of our series (20 months-16 years) all present clear dystrophic changes. Muscle regeneration is characterized by activation of the satellite cells, by their multiplication followed by their fusion giving birth to regenerative fibers. By studying the expression of muscular markers (vimentin, desmin, isoforms of the myosin heavy chains), it has been possible to define more precisely the degree of maturation and of differentiation of these regenerative fibers. Our results suggest that an abortive regeneration of the muscle fibers in Duchenne muscular dystrophy can explain, at least partly, the progressive evolution of this disease.

[Human cervico-facial morphogenesis. Evaluation of acquired data and current outlook. Second part: cervical morphogenesis]. / La morphogénèse cervico-faciale humaine. Bilan des données acquises et perspectives actuelles. (Seconde partie: La morphogénèse cervicale).

After having recalled the formation of the so-called "branchial" organisation, each component of the segmentary units constituting this organisation is analysed, as well as their particularities. This lead us to recognize the existence of only five branchial arches in the human embryo, without an intermediary arch between the fourth arch and the pulmonary arch. This question is moreover linked to the signification of the so-called "ultimobranchial" body, which must be connected with the fourth pharyngeal pouch. The question of cervical segmentation is inseparable from the question of cephalic metamerisation. Two segments are individualised in front of the mandibular process: the fronto-nasal process and the maxillary process, corresponding to premandibular arches, which existence is well established in paleontology. In addition to the peripheral expression of this cervico-cephalic segmentation marqued by primitive characters. We observe the paraxial expression of segmentation by the somitomeres and the somites. Recent data provided by the developmental genes confirm that only one process is at the origin of these two expressions which appear distinct, but lead to a unitary organisation. The mutation of the gene Pax 6 affecting in the same time the nasal placode and the optic vesicle confirms the unity of the fronto-nasal process. The pre-eminence of genetic expression on skeletal, muscular and nervous tissues with respect to the vascular system confirms the inadequacy of the criterion given by the aortic arches for the analysis of the cervico-cephalic development, although it is classically linked to the concept of an embryonic "branchial apparatus".

[Malformations of the nasal fossa and paramedian facial clefts. New perspectives]. / Malformations de la fosse nasale et fentes faciales paramédianes. Nouvelles perspectives.

Since choanal atresia may be associated with other cranio-facial malformations, including various degrees of nasal fossa malformation, and be a part of paramedian facial clefts, (as described by Tessier), they can be integrated into the larger group of neurocristopathies. We identified four such cases with combined clinical elements corresponding to Tessier's paramedian facial cleft, including eyelid coloboma, mild to severe choanal and nasal fossa anomalies, ethmoidal hypoplasia and anterior skull base malformation, sometimes with proboscis lateralis. These various malformations are due to abnormality of the olfactive placode and the adjacent mesenchyme. These discoveries incited us to elaborate a conception first of all on the pertinent embryology involved, second, to propose a new classification based on anatomical and pathogenic embryological considerations. And finally, since endonasal laser therapy is particularly dangerous in such cases, to propose the use of transpalatal approach to restore choanal permeability. Pediatric ENT surgeons should pay special attention to any small stigmatism of facial cleft when dealing with children affected by choanal atresia.

[Aspects of facial morphogenesis in the rat]. / Aspects de la morphogénèse faciale du rat.

The facial morphogenesis of the rat has been observed by scanning microscopy on embryos taken every day from the 10th post-coitum day to term. Three points should be noted. Firstly the muzzle has at the beginning of the development an individuality which tends to diminish later. Secondly the vibrissae, whose primary elements are grouped in plates, are of great importance in the development of the muzzle. Finally, the opening between the internal parts of the nasal ridges is elevated with at the top a sharp angle, contrary to that of man which is little elevated and is arched. This could express the difference relating in each of the two cases the mesenchymatous naso-dorsal center, to which divergence between the two types of face, one with muzzle and the other without, would be linked. The primates presenting these two types, the tendency at the moment is to classify them using this discrimination. The study of the two corresponding aspects would supply a precious addition to these observations.

[Demonstration of a correlation between the degree of pigmentation and the power of inactivation of isoniazid in man]. / Mise en évidence d'une corrélation entre le degré de pigmentation et la puissance d'inactivation de l'isoniazide chez l'homme.

In a group of 153 white subjects treated for tubercle, individual determinations were made of: a) The power of inactivation of isoniazid. b) The degree of pigmentation (iris, skin, hair) assessed by a weighted pigmented index of the iris. A statistical study of the results shows the clear existence of a narrow positive correlation between these two characters, such that the more pigmented a subject is, the greater is the chance of rapid inactivation of isoniazid. An attempt at a biochemical explanation is proposed. The results in the world literature (Japanese, Swedish, American) are in keeping with these observations. Thus, weakly pigmented tuberculous patients are potentially a new group at risk from anti-TB drugs.

[Role and significance of the branchial system in cervico-facial morphogenesis]. / Place et signification de l'appareil branchial dans la morphogenèse cervico-faciale.

The so-called "branchial" embryonic organization is in fact that of the part of the embryo subjacent to the anterior, encephalic portion of neural tube. It presents, in addition to its typical aspects, historically of importance, other more pertinent aspects related to its segmental character, its mode of development and its morphologic limits. Synthesis of all data is now possible due to recent precision of the origin of branchial muscles and the participation of ectomesochyme in its development. Findings indicate the predominant place and deep significant of this organization in overall embryonic development, for which it represents a determinant phase in itself, independent of evolutionary potential that can be possibly attributed to its vascular components.

Power of isoniazid acetylation and pigmentation; first experimental tests in the rabbit: comparison with clinical data.

A positive correlation has been observed clinically at the Centre Edouard Rist, Paris, between the degree of pigmentation and the power of isoniazid acetylation in so-called "caucasians". The investigation was based on a relatively small sample of 153 observations, but sufficient to allow a significant statistical analysis. Comparing the results with data published in the literature, it may be assumed that this relationship between the power of acetylation and pigmentation would be applicable to all human beings. The rabbit, having as in man a bi-modal distribution of the power of acetylation, was used for further research of this correlation in that animal. The results of this research in rabbits may be compared with those in man, but further studies are required in view of the interest of this comparison and of the possible consequences of the relationship of pigmentation and the degree of acetylation of isoniazid in human therapeutics.

[2 modalities in the embryogenic process of frontonasal cysts and fistulae]. / Deux modalités dans le processus embryogénique des kystes et fistules fronto-nasaux.

The two principal embryogenic theories, persistence of residual structures remaining after closure of the anterior neuropore and inclusion of epiblastic derivatives in the prenasal space, may be combined, with resulting two embryonic varieties of these malformations. Glabellar cysts, with or without fistulae extending them downwards, and which remaining at superficial level may perforate the true nasal bones. Other fistulae can develop which extend deeply and present variable dilatations with a more or less oblique path upwards depending on the level of their opening into the nose.

[Proboscis lateralis, a rare facial malformation. Therapeutic difficulties (apropos of a case)]. / Le proboscis lateralis, malformation faciale rare. Ses difficultés thérapeutiques (a propos d'une observation).

A case of proboscis lateralis with total absence of the corresponding half of the nose is reported. The length of the mucocutaneous cylinder enabled initial insertion of its free extremity around its bony orifice in communication with the single nasal fossa, and the creation of a functional, well situated naris. Second-stage operation several months later involved spreading of the upper part, closure of the coloboma, and treatment of the lacrimal pathways. Total liberation of the superior pedicle and final modelling is to be envisaged at a later date as a function of growth.

[Embryologic problems raised by proboscis lateralis]. / Problèmes embryologiques soulevés par le proboscis lateralis.

Organization is conserved in proboscis lateralis and in this respect it represents a half-nose and not a nasolacrymal canal. It is characterized by mainly skeletal deficiency and a paramedian lateral localization. Associated alterations involved olfactory and ocular structures, often with a disorder of closure of the colobomic slit, but overall neuroblast development is not disturbed. Effects on the subjacent facial regions are variable and remain lateral, the overall situation in relation to Tessier's fissure tending to clarify their significance. Comparison of the malformation with the different degrees of cyclopia and with the bifid nose confirms its origin from a particular form of embryogenic process. Significance of participation of the olfactory placodes and the neighboring ectomesenchyme is discussed, together with the modalities of this participation. The latent bilateral nature of the malformation must be recognized together with its embryogenic consequences.

[Embryogeny of facial, mastication, tongue, palate and neck muscles (author's transl)]. / L'embryogénie des muscles faciaux, masticateurs, de la langue, du voile et du cou.

The mesenchymal origin muscular tissues entailing some difficulties in the knowledge of certain muscles embryogeny, two methods are therefore applied: the comparison of the ontogenesis data with those of comparative anatomy and the use as a guide of the functional motor unit with which the muscle combines. In resorting to these methods necessary precautions are precisely defined. The origins of the concerned muscles are, at first, situated among those of the whole musculature subjected to will, which are of two types "somitic" and "branchial". The realities lying under these two misleading terms are analysed. Then the usual data on each of the muscular groups embryogeny reviewed and compared, if necessary, with recent works. For the facial muscles a confusion results from the use of the term platysma both in comparative anatomy and in embryology, in pursuance of transposition, exact on that particular point, of the philogenic development of these muscles in ontogenesis. The development of these muscles comes in the scope of the extensive general character of the superficial hyoïd arch derivatives, and their topographic and functional particularities should be brought together with the disposition of the facial nerve nucleus and its arising fibres. Among the muscles in action in the mastication, a link appears between their precise role in this function and their embryogeny. For the neck muscles, the spinal nerve systematisation and the variations of the sterno-mastoïd muscle in mammals agree in assigning to this muscle an entire somitic origin lying exactly at the junction with the so-called branchial muscles. The somitic origin of the tongue muscles and the sharing between the somitic and branchial origins of those of the soft palate bring to light the place in the organism of these two anatomic structures. Then, the conjunction of muscles proceeding thus from two origins in these anatomic structures carries a particular signification in man by reason of the language.