Congenital alar field defects: clinical and embryological observations

Congenital malformations of the nasal ala may occur as isolated unilateral nasal alar defects or as part of more severe facial clefting syndromes. The embryologic significance of the isolated alar deformity seems separate from other craniofacial deformities and justified comment. Clinical examples of isolated nasal alar malformations are correlated with a study of 60 human embryos ranging from seven to 10 weeks gestation. These studies indicate that the nasal and alar developmental fields each have a separate critical time during which cells are most susceptible to altered development.

Rapid nasal pit formation in mouse embryos stimulated by ATP-containing medium

The primary palate in the mouse is composed of epithelium and mesenchyme. Most studies on primary palate formation have concentrated on the role of the mesenchyme based upon the hypothesis that mesenchymal accumulation elevated the sides of the nasal placodes, thereby creating the depressed nasal pits. This study demonstrates that the epithelium is actively participating in formation of the nasal pits. Mouse heads from embryos of 14 to 24 paris of body somites were placed in medium 199 and photographed. The medium was replaced with medium containing 1.0 mM ATP and 0.05% Triton-X. Within 5 minutes, the placodes either thickened or invaginated. Control heads exposed to medium 199 containing only Triton-X or ATP did not show any invaginations. The rapid thickening and invagination stimulated by ATP-containing medium demonstrates that the epithelium is the dominant tissue in nasal put formation. Although mesenchymal accumulation certainly contributes to the formation of the primary palate, it is the placodal epithelial invagination that appears to shape the nasal pits.

Warfarin embryopathy in siblings

Two siblings were noted to have the physical stigmata of the fetal warfarin syndrome. Their mother had received warfarin sodium for thrombophlebitis during both pregnancies but not during that of an unaffected sibling. Teratogens may produce syndromes that mimic genetic disease in both phenotype and familial aggregation.

Congenital midline nasal muscle with associated nasal deformity

A case is presented of a congenital nasal deformity consisting of a midline nasal muscle, alar cartilage defect, and partially obstructed nostril. The embryology of nasal development is reviewed, and an attempt is made to explain this unique anomaly.

The nasal tip in bilateral and unilateral harelip

The anatomy of harelip is described, as well as attempts to correct it--bilaterally and unilaterally--in a manner producing normal nasal tips.

Development of olfactory and related structures in staged human embryos

The staged sequence of development of the olfactory and related structures has been established from the serially sectioned human embryos of the Carnegie collection, from stage 11 to stage 23. The nasal epiblastic thickening appears at stage 11 and the nasal field is well outlined at stage 12. At stage 15, a continuous cellulovascular strand is observed between the nasal groove and the olfactory field. The vomeronasal groove appears at stage 16 (O'Rahilly 1967). During stage 17, the olfactory nerve is organized into two plexuses, lateral and medial, the latter mingled with the terminal-vomeronasal complex. The olfactory bulb begins to appear at stage 18. Stage 19 is characterized by the individualization of the olfactory bulb and nuclei. In addition, the distinction between olfactory structures and terminal and vomeronasal ones begins to be clear. The structure of the olfactory bulb is evident at stage 21. At stage 23, the olfactory strands are well individualized, and olfactory and terminal-vomeronasal fibers are easily distinguishable. The terminal ganglion is rather terminal-vomeronasal with an autonomic terminal contingent and a sensory one attached to the vomeronasal system.

Median facio-cerebral anomalies in chick embryos resulting from local destruction of the anteriormost parts of the early neural plate and neural crest

With the aid of micro-laser irradiation, in a total of 123 chick embryos varying in age from 24-26 hours of incubation (2- to 6-somite stages), the anteriormost parts of the neural crest and the neural plate were eliminated. As a result of this treatment, 15 out of 59 embryos, studied 24 hours after irradiation, showed manifest signs of maldevelopment of the telencephalon, eyes and olfactory placodes. At the age of 7 days (6 days after irradiation), the surviving 25 embryos all proved to have developed median facio-cerebral anomalies. These anomalies included arhinencephaly, holoprosencephaly, anophthalmia, synophthalmia, microphthalmia, absence or reduction of the nasal structures, sometimes combined with the presence of a proboscis, and incidentally occurring facial cleft conditions. The 2 surviving 12 days' embryos studied showed similar facio-cerebral anomalies. These results show that median facio-cerebral deformities may devlop as a result of damage inflicted to the anteriormost parts of the early neural plate and neural crest.

Inhibition of rhinovirus replication in in organ culture by a potential antiviral drug

The compound 2-amino-1-(isopropyl sulfonyl)-6-benzimidazole phenyl ketone oxime (LY122771-72) at a concentration of 0.2 microgram/ml completely inhibited rhinovirus replication in human embryonic nasal organ cultures, although in the absence of virus the compound did not inhibit ciliary activity when used at a concentration of 25 micrograms/ml. When added 26 hr after infection, the compound stopped rhinovirus production in organ cultures that had already started to release virus. Five rhinovirus types available for infection of volunteers and six recently obtained clinical isolates were shown to be more sensitive to LY122771-72 in tissue culture than the rhinovirus type 31 used in the organ culture experiments. These results suggest that this potential antiviral drgu should be evaluated in humans.

Embryonic development of the head and neck: Part 3, The face

The embryology of the face is presented with respect to changes affecting the mandible, maxilla, upper and lower lips, palate, nose, and oral cavity. The embryonic development of the teeth and salivary glands is also included. Various facial clefts, including cleft lip and cleft palate, are discussed, in addition to some congenital anomalies affecting the nose and oral cavity.

Development of the olfactory organ in the rainbow fish Nematocentris maccullochi (Atheriniformes, Melanotaeniidae)

The development of the olfactory organ in the rainbow fish, Nematocentris maccullochi, was studied using scanning and transmission electron microscopy; it was compared with the developmental process in other teleosts, especially in the closely related atherinids and cyprinodonts. The formation of the nares parallels that in atherinids, salmonids, cyprinids and heterosomats, but differs from that found in cyprinodonts. Another ontogenetic feature in which the olfactory organs of the rainbow fish and also of atherinids differ from those of cyprinodonts, is the occurrence of transitory kinociliary cells which disappear during the postlarval period. The divergent evolutionary pathways are discussed with reference to experimental investigations. During development, ciliated and microvillous receptor cell types occur. At the primary larval stage ciliated receptor neurons are exclusively present. At a later stage the microvillous type develops and becomes equal in frequency. Thus, the microvillous receptor represents a separate type of olfactory neuron and is not a progenitor of the ciliated receptor cell.

Subdivision of mouse vibrissae on an embryological basis, with descriptions of variations in the number and arrangement of sinus hairs and cortical barrels in BALB/c (nu/+; nude, nu/nu) and hairless (hr/hr) strains

Development of vibrissae was studied in dd/y mouse embryos by scanning electron microscopy. Arrangement of vibrissae and cortical barrels were also studied by light microscopy in adult dd/y, BALB/c(nu/+), nude (BALB/c, nu/nu) and hairless (hr/hr) mice to find genetic or epigenetic variations. Rudiments of vibrissae first appear on Day 12 of pregnancy as longitudinal ridges on the developing muzzle, and each hair rudiment is represented by a dome on the ridges. The dorsal two rows (A and B; Woolsey and Van der Loos, '70) of mystacial vibrissae are on the lateral nasal prominence, while the ventral three (C, D and E) are on the maxillary prominence. Smaller hairs of mystacial vibrissae appear at the labial part of the maxillary prominenceon Day 13. The rudiments of rhinal hairs also appear at this stage on the part of the muzzle derived from the medial nasal prominence. Thus the so-called mystacial vibrissae should be subdivided into three (or 4, including the rhinal) groups on an embryological basis. They are the lateral nasal, the maxillary and the labial. A supernumerary sinus hair and a corresponding barrel was observed between D and C rows uni-or bilaterally in one third of individuals of BALB/c, nude and hairless mice. It is suggested that supernumerary hairs tend to occur between the groups of hairs as defined above. In nude and hairless mice small barrels representing labial hairs are diminished in number. The number of hair follicles, however, is normal.

Distribution of surface coat material on nasal folds of mouse embryos as demonstrated by concanavalin A binding

3H-concanavalin A and the concanavalin A-horseradish peroxidase staining technique were used to study the distribution of surface coat material on the epithelium of the nasal folds and nasal groove of mouse embryos. In stages shortly before and during epithelial fusion concanavalan A stained or labeled material was present at apical surfaces of epithelial cells of the nasal groove and nasal folds. Silver grains, representing bound 3H-concanavalin A, were counted in defined areas of the nasal groove and presumptive fusion area in both anterior and posterior regions of the nasal folds. For both stages examined there was a significant increase in the amount of 3H-concanavalin A bound by presumptive fusion areas in posterior regions of the nasal folds as compared with anterior regions; i.e., the atact between the nasal folds. This finding is consistent with results from investigations of palatal shelf and neural fold fusion which suggest that increased synthesis of surface coat material is associated with adhesion and fusion of epithelial folds and shelves.

Dermoid cysts of the nose: review of 21 cases

Twenty-one cases of histologically confirmed dermoid cysts of the nose are reviewed. The sites involved were the dorsum (18), septum (5), glabella (2), nasal tip (2), and columella (1), with several patients having multiple sites of involvement. Bony or cartilaginous destruction occurred in 14 patients (67%). A sinus tract was evident in ten patients (48%). Complete excision of these lesions is necessary for prevention of recurrence. The differential diagnosis includes hemangiomas, gliomas, encephaloceles, epidermoid cysts, neurofibromas, and lipomas.

[Development of the nasal cavity and formation of the nostrils in human embryogenesis]

The development of nasal cavity was traced in human embryos. The identity in the primitive formation of the mouth cavity and that of the nasal cavity is stated. During embryogenesis, the primitive nasal cavities are demonstrated to change their position concerning the mouth cavity. Epithelial "cluster" formation in the area of the nostrils is examined: it appears in embryos of 16-19 mm long, is mostly prominent in embryos of 50-55 mm long, is absent in fetuses of 5.5 months old. By comparing the terms and dynamics in the development of epithelial adhesion in the larynx an the nostrils, the importance of these temporal structures for protecting the respiratory tract of the embryo from amniotic fluid is demonstrated.

Placodes of the chick embryo studied by SEM

The otic, the lens and the nasal placodes have been examined in chick embryos between stages 10 and 18 of Hamburger and Hamilton. At the stage when each placode first becomes visible conspicuous differences have been seen in the surface morphology between those cells which will invaginate and form the placode and those which will remain on the surface of the head, forming the epidermis. The differences become more pronounced with increasing development. The placode cells possess many surface projections whilst the epidermal cells do not. These differences in surface morphology are related to other differences which are visible in TEM sections, the placode cells being highly columnar and extending the full depth of the placode, whilst the epidermal cells are cuboidal or even squamous. This modification in cell shape of the placode cells is correlated with the presence of longitudinally orientated microtubules. The mechanism of invagination is discussed and evidence is presented which supports the idea that there is a migration of cells into the placode from one side. Such a phenomenon would help to explain the asymmetrical structure of the placode, including the presence of the overhanging lip.

Concanavalin A binding to the epithelial surface of the developing mouse olfactory placode

Concanavalin A (Con A), a lectin binding to mannosyl and glucosyl residues of glycoproteins and glycolipids, was used to study the appearance of carbohydrate-rich cell surface material on the olfactory placode and nasal processes which contribute to formidine was also used in an attempt to correlate changes in labeling index with formation of the olfactory placode and nasal processes. The cell surface of the early frontonasal epithelium binds Con A very little, if at all, but Con A binding was observed when the olfactory placode could be identified as a plate of cuboidal cells that exhibited a reduced labeling index. During the period of formation of the nasal processes, Con A binding was observed on the facial epithelium including the presumptive contact region. There was also a decline in the labeling index throughout primary palate formation. This study provides three criteria by which the olfactory placode can be identified: a morphological change of placode cells to a cuboidal shape, a synthesis or rearrangement of surface coat material that binds Con A, and a reduced labeling index.

Intra-uterine healing of fetal rat oral mucosal, skin and cartilage wounds

Orofacial wounds, including rupture of the palate, were surgically created in utero on 19 1/2 day Sprague Dawley rat fetuses. Six hours prior to sacrifice 0.1 mgm/100 gm maternal body weight of colchicine was injected subcutaneously. Five fetuses in each group of operated and unoperated controls were sacrificed at 0, 24, 48 and 72 h postoperatively. Serial histological sections in the frontal plane were stained with hemotoxylin and eosin and modified Mallory's. Rapid and complete epithelialization of oral and skin wounds was observed within the 72 h period. There was a complete lack of inflammatory response, scab formation and involvement of nasal epithelium in healing. Nasal cartilage wounds rapidly rounded off and the perichondrium reformed without evidence of callus formation. These findings are discussed in regard to the etiology of some congenital defects and the prospects of fetal surgical correction of orofacial deformity.

Anatomical and functional account on the lateral nasal cartilages

Due to the fact that the literature in the last 20 years shows contradictory points of view regarding the morphology and relations among the nasal cartilages in man, gross, semi-macroscopic and light-microscopic surveys were carried out in 20 adult and fetal human noses. It was concluded that the septodorsal cartilage is made up of only one block. The attachment of the septodorsal cartilage to the nasal bones takes place from 2 to 5 mm in the inner aspect of the latter. The distal and fibrous portions of the lateral cartilage and the greater alar cartilages act as valves.