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During embryonic and foetal development, the masseter is formed from two successive generations of muscle fibers in a manner which is very similar to that which has been previously described for other skeletal muscles. This phenotype is characterised by the persistence of ontogenic myosin isoforms (embryonic and foetal myosin heavy chains, embryonic light chain) and by the presence of two distinct populations of fibers: small diameter fibers which coexpress the embryonic, foetal and fast isoforms of the myosin heavy chains but never express the slow isoform; large diameter fibers which express the slow myosin heavy chain either exclusively or in variable associations with the other isoforms. These characteristics of the human masseter muscle probably correspond not only to its embryological origin and its special innervation, but also to the functional constraints to which it is submitted after birth.

Meckel's cartilage plays an important role in the topographical organisation and in the differentiation of the facial structure during the embryonal and even much later during the foetal period. Our observations on serial sections carried out in two human foetuses aged 12 and 16 weeks indicate that the two dorsal (tympanic) and ventral (mandibular) branches of Meckel's cartilage are perfectly defined at 16 weeks. In the dorsal branch, the primordia of the incus and of head of the malleus are still composed on non-ossified cartilage. In the ventral branch, it is also possible to describe at 16 weeks three posterior, medial and anterior parts which are composed of cartilage. The initiating role played by the ventral part of Meckel's cartilage on the ossification of the mandible leads during the embryonal period to the formation of the mandibular primary growth center, which is therefore clearly defined in our first stage at 12 weeks. The partial fibrous evolution and the regression of the major part of the ventral branch of Meckel's cartilage only start after 16 weeks of intrauterine life.

The cervical muscles have a dual postural and dynamic function, in order to ensure both the stability and the motility of the cervical spine. The functional duality together with the complexity of the cervico-cephalic system render the study of the cervical muscles difficult, and their physiology is not fully understood in humans. This study has been carried out on ten samples from the m. longus colli, taken during a surgical procedure in patients aged between 36 to 62 years. The histological study combined enzyme histochemical (ATPases) and immunohistochemical techniques (using antibodies specific for the slow and the fast isoforms of the myosin heavy chains). Our results indicate that, in all cases, the m. longus colli is composed of muscle fibers with peripheral nuclei and with a relative dispersion in size. Histochemically, the type 1 and type 2 fibers express exclusively either the slow or the fast myosin heavy chain. From a quantitative point of view, the proportion of the slow fibers varies between extreme values of 30 and 73%; in addition, the dispersion in fiber size predominates on the fast type 2 fibers which are smaller than the slow type 1 fibers. Thus, most of the muscles that we have studied have histologically a slow predominance. This predominant expression of a slow phenotype in the m. longus colli corresponds to its important postural function, in addition to its phasic role during the flexion of the cervical spine.

In adults, the predominant expression of a slow phenotype in the m. longus colli corresponds to its important postural function. Morphologically, there is a dispersion in fiber size predominating on the fast type 2 fibers which are significantly smaller than the slow type 1 fibers. We deemed it of interest, therefore, to analyze the metabolic differentiation of the muscle longus colli during its development. This study has been carried out on six anatomical samples, in foetuses aged between 16 and 40 weeks of pregnancy and in an 18 month-old child. The histological study combined H&E staining and immunohistochemical techniques (using antibodies specific for the slow and the fast isoforms of the myosin heavy chains). Our results indicate that the m. longus colli differentiates during the foetal period in a way which is quite comparable to that of other skeletal muscles, such as the quadriceps. In this series, a major slow predominance with a significant dispersion in fiber size was first observed in the 18 month-old child. Thus, it can be concluded that the establishment of the adult phenotype of this muscle starts during postnatal life, following the development of the mechanisms holding up the head and neck and leading to the appearance of the cervical lordosis.

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.

Foetal maturation of the skeletal fibers in the anorectal sphincter and in the vesico-urethral sphincter follows a dorso-ventral gradient, in parallel with the development of their motor innervation. The anatomical situation of the m. puborectalis, which early development plays an important role in the establishment of the foetal anal continence, suggests that this muscle should also be submitted to this gradient. We have studied in parallel the development of both the ventral and the dorsal parts of the m. puborectalis in human foetuses aged between 19 and 40 weeks of pregnancy. The results indicate that the transversal thickness of the muscle increases progressively during pregnancy, with a dorsal part being always thicker than the ventral one. More interestingly, the increase in the diameter of the muscle fibers becomes significantly more important at the level of the dorsal part between 25 and 40 weeks of pregnancy. This last result confirms the existence of a dorso-ventral gradient of growth and maturation of the m. puborectalis, as part of the global mechanisms involved in the development of the striated musculature of the pelvic organs.

The development of the foetal anorectal continence is related to the appearance of the anatomical components of the sphincter. The present study has been carried out in order to analyse the development of the smooth and striated components of the anorectal sphincter, in a series of 7 embryo and foetuses aged from 10 to 40 weeks of pregnancy. Our results indicate that the external sphincter, the puborectalis muscle and the internal sphincter are present before 24 weeks, although they obviously play variable roles in the establishment of the foetal continence. The internal sphincter becomes quantitatively important after 14 weeks, and is likely to be responsible for the establishment of the initial continence. The growth of the striated components during the foetal period corresponds to the maturation of the innervation and of the voluntary mechanisms controlling continence. Intrication of smooth and striated muscle components in the external sphincter starts after the end of the embryonic period. All the anatomical components of the anorectal sphincter are present at birth.

The spinal muscles, located in the paravertebral region, derive embryologically from the medial part of the somites. It has been shown in different animals that their differentiation occurs within the somite itself following the action of diffusible factors of chordal, neural and epiblastic origin. In these animal species, it thus appears that several factors determine the potential of migration as well as the muscular specification of the somitic cells. In 13 human foetuses, aged from 12 to 40 weeks of pregnancy, without any neuro-muscular disorder, transversal sections of both the vertebral and the paravertebral regions have been made at the level of the thorax and of the abdomen. Following rapid fixation, decalcification and paraffin embedding, semi-serial histological sections of 10 microns have been stained with H&E or Masson's trichrome and examined under light microscopy. Our results confirm that the primordia of the spinal muscles are present before the end of the embryonic period proper. The main modifications observed during foetal life concern the overall growth of the muscular mass, with a neat preeminence of the lombar region after 18 weeks. The differentiation of the individual muscle fibers is similar to that observed in other territories in the developing organism, with a craniocaudal gradient of maturation. Thus, if myogenic specificities really exist in the medial part of the somites in humans, it is likely that they concern the initial mechanisms involved in the activation of the myogenic program and not the mechanisms leading to the subsequent differentiation and growth of the fibres.

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.

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".

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.

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.

Background: The rare association of mixed gonadal dysgenesis and non classical congenital hyperplasia by 21-hydroxylase deficiency poses the problem of their respective responsibility in the development of sexual ambiguity., Case Report: In a newborn with ambiguous genitalia, blood 17-OH progesterone was moderately elevated (3.9 to 14.1 ng/mL) leading to the diagnosis of non-classical 21 hydroxylase deficiency, Molecular studies later confirmed this diagnosis. However, the presence of a palpable gonad and the karyotype (45 X/46 XY mosaicism) indicated a mixed gonadal dysgenesis as the cause of sexual ambiguity. Histological examination revealed the presence of a testis and a streak gonad., Conclusion: This observation emphasizes the need for a complete clinical and biological analysis in all newborns with sexual ambiguity.

During the metabolic differentiation of developing human skeletal muscle fibers, two different generations of fibers can be characterised by their profiles of protein expression (in particular of the myosin heavy chains). This differentiation is regulated by both genetic and epigenetic factors (motor innervation, levels of thyroid hormone). The anomalies in different muscle pathologies can be better understood by comparison with the modifications occurring during normal skeletal muscle development.

Anorectal sphincteromyectomy is a suitable answer to the problem of the chronic constipation in childhood. It took a long time to be recognized beside others methods as biofeedack. This surgical procedure has been described for the first time by B. Duhamel in 1965; we still remained faithful and proud of this idea. We wanted to understand and to explain the basis of the conception of anorectal achalasia. Several works about the fetal development of the anorectal sphincter tried to explain it. A good exposition makes the technique less difficult and the dissection of the internal sphincter easier. We have analysed our 22 recent children. In 21 cases, we noticed a good result. The histological study of the fragment of the myomectomy showed a normal cytology of the smooth muscular tissue, a normal intrinsic innervation and arterial vascularisation. The surgical procedure is efficient because it relieves the functional disorder of the internal anal sphincter. It is a mechanical action; the external sphincter finds again its normal function, or is allowed to be reeducated.

Muscle biopsies were taken at the oesophageal opening and in the costal part of the diaphragm from 15 foetuses (aged between 11 and 40 weeks) and from four children aged 1 week, 5 months, 3 and 16 years. Subjects with multiple congenital abnormalities or neuromuscular diseases were not included in this study. Enzyme histochemistry (myosin ATPases) and immunohistochemistry using antibodies directed against vimentin, desmin, titin and different isoforms of the myosin heavy chains (MHCs) were carried out on serial frozen sections. The diameters of the different types of fibres were measured using a Leitz ASM 68K and the corresponding results were expressed either as mean values or as histograms. In both of the regions of the diaphragm which were examined (oesophageal opening and costal portion). The skeletal muscle fibres are formed from two successive generations in a manner very similar to that which we have previously described for the limb muscles. The chronology of the various events involved in the maturation of the diaphragm does however present certain distinctive features since the adult MHCs are expressed well before 30 weeks even though paradoxically large amounts of fetal MHC were still present at birth. These findings suggest the existence of a special regulatory mechanism in the diaphragm resulting either from its innervation by the phrenic nerve or from its specific functional constraints.

Muscle biopsies were taken from the superficial portion of the M. masseter in 10 foetuses (aged between 12 and 38 weeks), in a child of 18 months and in an adult without any neuromuscular disease. Serial frozen sections were processed for immunocytochemistry using antibodies specific for the embryonic, foetal, slow and fast myosin heavy chains (MHCs). Diameter of the different types of fibers were measured with a Leitz ASM 68 K; the results have been expressed as average diameters and histograms. During foetal development, the masseter is formed from two successive generations of muscle fibers in a manner very similar to that which has been previously described for other skeletal muscles. After birth, a particular phenotype appears. This phenotype is characterised by the persistence of embryonic and foetal MHCs and by the presence of two distinct populations of fibers: small diameter fibers which coexpress embryonic, foetal and fast myosin isoforms but never express the slow MHC; large diameter fibers which express slow myosin either exclusively or in variable associations with the other isoforms.

In Gabon, 15 children aged 13 to 36 months admitted for malnutrition with chronic diarrhea underwent a small bowel biopsy for detection of parasites in the duodenal contents and histologic evaluation of the intestinal mucosa. In every case, intraepithelial lymphocyte counts (IELC) were under the lower limit of normal for children and adults, regardless of whether or not parasites were found. Partial villous atrophy was a consistent finding. Proportion of lymphocytes among intraepithelial cells was 7.4% in the 6 children with no parasitic infection, 7.9% in the children with giardiasis, and 8.1% in the children with strongyloidiasis. Appropriate treatment of the parasitic infections was quickly followed by resolution of the diarrhea in the nine patients with demonstrable intestinal parasites. These data should be compared with the well documented lymphocyte function anomalies associated with protein-calory malnutrition. The fall in IELC and lack of response to local anigenic stimulations are features of malnutrition.

An intestinal permeability test (IPT) analysing the mannitol (M) and lactulose (L) clearances and the L/M ratios was performed in 15 children followed for celiac disease, before the onset of exclusion diet, during the gluten-free diet and after the reintroduction of gluten. The results showed a significant increase of the L/M ratios under normal diet, with respect to a control population. This increase was related to an increased L urinary excretion and to a decrease in M excretion. During gluten-free diet a normalization of the L/M ratios was observed. Reintroducing gluten altered the L/M ratios by increasing the L intestinal permeability and decreasing the M intestinal permeability. This study shows the value of the non invasive L/M IPT for the screening and monitoring of celiac disease in children.

Muscle biopsies were taken from the medium portion of the vastus lateralis of a hundred fetuses (aged between 10 and 40 weeks), children, adolescents and adults without any neuro-muscular disease. Diameters of the muscle fibers were measured with a Leitz ASM 68K on frozen sections which had been stained for myofibrillar ATPase. The results have been expressed as average diameters and histograms. The results demonstrated a gradual increase in diameter of the fibers during fetal development. At the birth, the average diameter of the type I and II fibers is 10-15 microns. Growth continues during postnatal development up until puberty, when the fibers reach their final diameter of 60-65 microns. Analysis of the histograms shows that before 18 weeks of gestation, there is a large dispersion in the diameter of the fibers. The first type I fibers are larger than the others and correspond to Wohlfart type b fibers. This is followed by the appearance of a second population of smaller type I fibers. These fibers gradually increase in diameter and one observes a homogenous population of type I fibers at the birth.

A case of pregnancy with Limb-girdle dystrophy is presented. The course of pregnancy remained uncomplicated, the patient has been delivered at 42 week's gestation by cesarean section, performed for dystocia and fetal distress. Histological and immunohistochemical examinations of the myometrium were unable to show its involvement in the muscular disease. The influence of the muscular disease and the route of delivery for such patients are discussed.

In order to obtain a better understanding of the anorectal continence in the newborn child, the development of the anorectal sphincter was studied in 25 embryos (3 to 60 mm CR), sectioned in the sagittal, transversal and frontal planes. A macroscopic study was also performed in 20 human embryos, completed by a light microscopic study and by a morphometric analysis of the smooth and striated components of the sphincter. The anorectal sphincter is composed of three parts: the external sphincter, which appears in the early embryos as a condensation of mesenchymal tissue around the anorectum. It receives smooth longitudinal fibers later; the m. puborectalis appears before 10 weeks and forms a sling around the anorectum; the internal sphincter, which is only well differentiated at 10 weeks and grows after the rupture of the anal membrane. This study emphasizes the importance of the anorectum in the development of its own sphincter.

An anatomo-clinical observation of toxoplasmic pneumonia with generalization in a six-year old child is reported. The serology of toxoplasmosis is positive. The histopathological examination revealed an interstitial pneumonia with toxoplasma located in the tumified alveolar lining cells and in the intra-alveolar macrophages. Parasitic lesions were also observed in the myocardium, peripheral striated muscle, liver, spleen, adrenal gland, lymph nodes, digestive tract and bone marrow. In the absence of the isolation of a toxoplasma strain, the diagnosis was based on the examination of a bone marrow smear performed the day before death. The proliferating forms of Toxoplasma gondii were abundant and characteristic. These data were confirmed by an ultrastructural study of toxoplasma in the lung and myocardium of the patient. In rapidly evolutive generalized toxoplasmosis of this type, the existence of a particular site is obvious but difficult to define. However, this study points out the usefulness of a bone marrow study in the hope of determining an etiological diagnosis with little delay which would thus increase the chances of an effective therapy.

The adrenal glands from a series of 300 fetuses and infants which had died in the Hospital Saint-Vincent-de-Paul, Paris, were dissected, weighed and processed for routine histology. The development of the fetal cortex and its regression have been compared to the general development of the gland. Our results show that there is an important development of the fetal cortex up to birth, when the adrenal glands represent almost one third of the size of the kidneys and possess only very reduced permanent cortex and practically no medulla. The regression of the fetal cortex in the postnatal period is marked by a decrease in weight of the adrenal glands up to the 2nd or 3rd month, by the persistence of a few dispersed cells up to the fifth month and by the persistence of a few fibrous elements up to 2 years of age.

In 30 cases of trisomies 13, 18 and 21, the placenta showed different lesions of hypotrophy, immaturity, hydrops, trophoblastic recurrences or cysts and mineralisation of the trophoblastic basal lamina. These are non specific lesions and can be observed in a variety of conditions, but their association is striking in most cases of trisomies. Different pathological patterns may thus evoke a trisomy, though that diagnosis can only be ascertained by chromosome analysis.

Rhabdomyosarcomas were observed at birth in two premature infants. The evolution of these tumors was both rapid and fatal. One case was a botryoid sarcoma of the bladder and the second was a cervical alveolar sarcoma of Riopelle and Thériault. A cytological differentiation of the tumor was observed in the first case spontaneously and in the second following chemotherapy. In the second case histology, immunocytochemistry and a novel biochemical analysis of the contractile proteins demonstrated this differentiation of the tumor. The cellular reactivity varies according to the degree of muscular differentiation that can be defined either by studying the type of intermediate filaments present or the expression of specific muscle contractile proteins.

A scanning electron microscopic study of the coxo-femoral articular cartilage was performed in ten human fetuses aged from 15 to 40 weeks. An irregular surface was observed at the level of both femoral head and acetabulum. These surface irregularities are modified during development.

The authors studied early changes in immune state by the nuclear refringence test in 12 patients undergoing gynaecological surgery for non-malignant conditions. The test was performed before and thirty minutes after the induction of anaesthesia. Twenty five per cent of the patients showed abnormalities of the nuclear refringence test in the presence of Con A2. The interpretation of the results and the predictive value of the test are discussed.