Comparative growth in the olfactory system of the developing chick with considerations for evolutionary studies.

Despite the long-held assumption that olfaction plays a relatively minor role in the behavioral ecology of birds, crown-group avians exhibit marked phylogenetic variation in the size and form of the olfactory apparatus. As part of a larger effort to better understand the role of olfaction and olfactory tissues in the evolution and development of the avian skull, we present the first quantitative analysis of ontogenetic scaling between olfactory features [olfactory bulbs (OBs) and olfactory turbinates] and neighboring structures (cerebrum, total brain, respiratory turbinates) based on the model organism Gallus gallus. The OB develops under the predictions of a concerted evolutionary model with rapid early growth that is quickly overcome by the longer, sustained growth of the larger cerebrum. A similar pattern is found in the nasal cavity where the morphologically simple (non-scrolled) olfactory turbinates appear and mature early, with extended growth characterizing the larger and scrolled respiratory turbinates. Pairwise regressions largely recover allometric relationships among the examined structures, with a notable exception being the isometric trajectory of the OB and olfactory turbinate. Their parallel growth suggests a unique regulatory pathway that is likely driven by the morphogenesis of the olfactory nerve, which serves as a structural bridge between the two features. Still, isometry was not necessarily expected given that the olfactory epithelium covers more than just the turbinate. These data illuminate a number of evolutionary hypotheses that, moving forward, should inform tradeoffs and constraints between the olfactory and neighboring systems in the avian head.

Is the maxillary sinus volume affected by concha bullosa, nasal septal deviation, and impacted teeth? A CBCT study.

PURPOSE: Various mechanisms play an important role in the growth of maxillary sinus cavities. The purpose of this study was to investigate the correlations of maxillary sinus volume (MSV) with nasal septal deviation (NSD), concha bullosa (CB) and impacted teeth using cone-beam computed tomography (CBCT) images. METHODS: From 55 patients, a total of 110 maxillary sinus images were obtained and examined. Data including age, gender, impacted third molar, canine teeth, NSD, and CB were examined. MSV was measured using the MIMICS software (Materialise HQ Technologielaan, Leuven, Belgium). All statistical analyses were performed using the SPSS (Statistical Package for Social Sciences, version 21) software and p values < 0.05 were considered to indicate statistical significance. RESULTS: Mean volume of the right maxillary sinus was 13.566 cm3, while the left was 13.882 cm3. The rate of patients with right and left impacted third molar teeth was 49.1% and 47.3%, respectively. The rate of right and left impacted canines was 1.8% and 5.5%, respectively. NSD was found in 56.4% of CBCT examinations and right and left CB were observed in 30.9% and 32.7% of the patients' examinations, respectively. Males had a significantly higher mean sinus volume than females for both sides (p < 0.05). There were no significant correlations between MSV and age (p > 0.05). No significant differences were found between MSV and impacted teeth, NSD and CB (p > 0.05). CONCLUSION: NSD, CB, impacted teeth, and age were not found to be related to MSV. Gender had an effect on MSV and males had higher mean sinus volume than females.

FGF20-Expressing, Wnt-Responsive Olfactory Epithelial Progenitors Regulate Underlying Turbinate Growth to Optimize Surface Area.

The olfactory epithelium (OE) is a neurosensory organ required for the sense of smell. Turbinates, bony projections from the nasal cavity wall, increase the surface area within the nasal cavity lined by the OE. Here, we use engineered fibroblast growth factor 20 (Fgf20) knockin alleles to identify a population of OE progenitor cells that expand horizontally during development to populate all lineages of the mature OE. We show that these Fgf20-positive epithelium-spanning progenitor (FEP) cells are responsive to Wnt/ß-Catenin signaling. Wnt signaling suppresses FEP cell differentiation into OE basal progenitors and their progeny and positively regulates Fgf20 expression. We further show that FGF20 signals to the underlying mesenchyme to regulate the growth of turbinates. These studies thus identify a population of OE progenitor cells that function to scale OE surface area with the underlying turbinates.

The effects of choanal atresia on development of the paranasal sinuses and turbinates.

PURPOSE: The objective of this study was to evaluate the volume of paranasal sinuses (PNS) and turbinate in patients with unilateral choanal atresia (CA). MATERIALS AND METHOD: Computed tomography images of PNS in 11 individuals with unilateral CA were evaluated retrospectively. Mucosal thickness and volume of the maxillary, frontal and sphenoidal sinuses were determined, in addition to the volume of the middle and inferior turbinate. The unaffected nasal side of patients was used as a control group for the measurements. The results comprised the measurements of the atresic side compared to those of the healthy side. RESULTS: There was no significant difference between the atresic and healthy side of the nose in patients with CA with respect to mucosal thickness and volume of the PNS (the maxillary, frontal and sphenoidal sinuses) and the middle and inferior turbinate (p > 0.050). CONCLUSION: The complete absence of nasal unilateral airflow had no effect on the development of the PNS and the middle and inferior turbinate. Moreover, mucosal thickness in the sinuses was similar to that in the control group.

The effects of naris occlusion on mouse nasal turbinate development.

Unilateral naris occlusion, a standard method for causing odor deprivation, also alters airflow on both sides of the nasal cavity. We reasoned that manipulating airflow by occlusion could affect nasal turbinate development given the ubiquitous role of environmental stimuli in ontogenesis. To test this hypothesis, newborn mice received unilateral occlusion or sham surgery and were allowed to reach adulthood. Morphological measurements were then made of paraffin sections of the whole nasal cavity. Occlusion significantly affected the size, shape and position of turbinates. In particular, the nasoturbinate, the focus of our quantitative analysis, had a more delicate appearance on the occluded side relative to the open side. Occlusion also caused an increase in the width of the dorsal meatus within the non-occluded and occluded nasal fossae, compared with controls, and the position of most turbinates was altered. These results suggest that a mechanical stimulus from respiratory airflow is necessary for the normal morphological development of turbinates. To explore this idea, we estimated the mechanical forces on turbinates caused by airflow during normal respiration that would be absent as a result of occlusion. Magnetic resonance imaging scans were used to construct a three-dimensional model of the mouse nasal cavity that provided the input for a computational fluid dynamics simulation of nasal airflow. The simulation revealed maximum shear stress values for the walls of turbinates in the 1 Pa range, a magnitude that causes remodeling in other biological tissues. These observations raise the intriguing possibility that nasal turbinates develop partly under the control of respiratory mechanical forces.

Nasal turbinate enlargement due to cartilage and bone proliferation: a normal developmental finding in young ferrets.

Toxicity studies of intranasally administered, live attenuated influenza virus vaccine candidates conducted in male and female ferrets led to the microscopic observation of individual differences in the size of nasal turbinates, especially in the dorsal aspect of the nasal cavity. The association of these enlarged turbinates with acute to subacute inflammation, which is sometimes common in ferrets given live attenuated influenza virus vaccine candidates, led to this detailed microscopic evaluation of turbinate enlargement (cartilaginous and osseous thickening, or COT) in control animals dosed intranasally with saline. Results of this evaluation led to the conclusion that COT is a normal developmental feature of growing ferrets, irrespective of inflammation in nasal tissues or inflammatory exudate in the nasal cavity.

Facial growth after middle turbinate resection: an experimental study in the rabbit.

BACKGROUND: The aim of this study was to determine the effects of total middle turbinate resection on midfacial growth through a morphometric analysis on an animal model. METHODS: Twenty-eight male New Zealand white rabbits were used. The animals were divided into three groups: group 1, elevation and relocation of the nasal bone was performed; group 2, concha resection was performed; group 3, control group with no surgical procedure. The surgery was done at 8-10 weeks of age and the skull of each subject was sampled as they reached maturity. The determined distances then were measured by using landmarks identified on skull. The supplied data were evaluated by using the Mann-Whitney U test. RESULTS: Deviation of the nasal axis to the opposite side of the resected concha and an increase in the width of nasal bone were observed only in group 2. In group 1, an increase of nasal bone length and zygomaticonasal distances was determined in both the operated and the unoperated sides of nasal bones. CONCLUSION: This animal experiment showed that operations on the nasal bone or concha resection affected the midfacial growth in rabbits. The effects of middle turbinate resection to midfacial development should be evaluated by additional studies. We recommend only limited, conservative surgical procedures on the middle turbinate, saving all the vital mucosa, periosteum, and bone.

Expression patterns of galectin-1 and galectin-3 in nasal polyps and middle and inferior turbinates in relation to growth regulation and immunosuppression.

BACKGROUND: The term nasal polyposis describes benign growth processes in the nasal and sinus mucosa, which are mainly located in the middle meatus and never in the inferior meatus. As a step to define the biochemical determinants relevant for growth regulation, we focused on endogenous lectins known for anti-apoptotic (galectin-3) and immunomodulatory (galectin-1) activities. DESIGN: Using computer-assisted microscopy, we performed an immunohistochemical investigation defining the quantitative parameters of expression of galectin-1 and galectin-3 in 10 nasal polyps, 10 middle turbinates, and 10 inferior turbinates, all of which were obtained from surgical resection. RESULTS: Our data show that galectin-3 expression is markedly (P<.001) higher in nasal polyps than in turbinates. No relation to the allergic status was discovered. Galectin-1 expression is higher in nasal polyps than in middle turbinates (P<.001) in nonallergic patients compared with allergic ones (in glandular epithelium, P =.009; in connective tissue, P =.006). The lowest galectin-1 expression was observed in the middle turbinate. CONCLUSIONS: These data are in line with a positive influence of galectin-3 on growth and an immunoregulatory role of galectin-1, mimicking an increased expression dependent on glucocorticoid.

Developmental analysis of the peripheral olfactory organ of the opossum Monodelphis domestica.

The gray, short-tailed opossum, Monodelphis domestica, is born in a very immature state after a brief (14-day) gestation. As a result, the species provides a unique opportunity to examine very early periods of mammalian development. The present study provides the first detailed morphometric analysis of the development of the olfactory mucosa and the nasal cavity in Monodelphis. The extent of the sensory mucosa increases dramatically across development, covering a growing nasal cavity and increasingly elaborate turbinates. Both nasal cavity convolution (a measure of turbinate complexity) and mucosal surface area show extensive growth between birth and adulthood. These measurements are greatest in the central portion of the mucosa (in the caudal portion of the nose) at all ages examined. A developmental BrdU study reveals a robust decrease in cellular proliferation with age; proliferation decreases to near adult-like patterns by postnatal day (P) 40. Results from these studies show that there is dramatic structural and cellular postnatal growth in the opossum peripheral olfactory organ.

Development of the paranasal sinuses in children.

The development of computed tomography and functional endoscopic sinus surgery has improved diagnosis and management of sinusitis. It has also renewed interest in the developmental anatomy of the paranasal sinuses. There are significant differences between adult and pediatric sinus anatomy, and to safely perform functional endoscopic sinus surgery in children, the surgeon must be aware of these differences. To define the developmental anatomy of the paranasal sinuses, we analyzed 145 computed tomograms from patients under 18 years of age. The study emphasized landmarks at the level of the maxillary sinus ostium. In addition, distances and angles from the nasal spine to various points in the sinuses were determined. The structures were identified and traced on a digitizing tablet. Means and standard deviations were calculated for each measure as a function of age. This study can aid a better understanding of sinus development in children and provide guidance to the endoscopic sinus surgeon.

Osteogenesis and growth of the nasal ventral conchae of the piglet.

The present study investigated the osteogenesis and growth of the nasal ventral conchae of piglets aged from 1 to 28 days. Serial transverse sections of paraffin wax-embedded noses were stained and examined by light microscopy. Bone formation occurred in a rostrocaudal direction in the ventral scroll, dorsal scroll, connecting zone, transverse lamina and articular lamina, successively, and occurred by two ossification processes: endochondral ossification and intramembranous bone apposition. Endochondral ossification was responsible for the longitudinally, rostrally directed growth. Rapid transverse bone growth and modelling were centrifugally directed and occurred by intramembranous bone apposition at the eccentric side of the scrolls and resorption at the concentric scroll side. Elongation of the distal scroll extremities took place by intramembranous bone apposition.

[Organization of the bone system of the nasal septum and its homologues. V]. / Organizacja zrebu kostnego przegrody nosa oraz jej homologów.V.

The aim of these anatomo-comparative investigations was the differentiation and systematization of the osseous nasal septum and vomer complex in rhesus monkeys (Catarrhina). ). The material consisted of 66 monkey heads: 52 of the fixed in formaline solution and 14 naturally macerated. The methodology was described elsewhere (part--1). The nasal osseous system philogenetically was presented in rhesuses only by alar bone. As lower--secondary part of septum emerges the typical parasphenoid complex. The alar bone in monkeys is homologous monominal elements (septal and subnasal bones) in pairhoofed mammals, birds, fishes and amphibians. It proves that in rhesuses as others Craniota the "mesoethmoid" and "ethmoidal bone" do not exist. In the skull of these monkeys the axially palate system was proved. This system does not dominate in the mechanics of the splanchnocranium.

Topography and differential growth of the nasal ventral concha (os conchae nasalis ventralis) of the pig from birth to six weeks of age.

To study the growth of nasal ventral concha (os conchae nasalis ventralis) of pigs between birth and 6 weeks of age, 7 undecalcified 80-micron thick nasal cross sections between the 3rd incisor and the 3rd premolar teeth were examined by microradiography and fluorescence microscopy, after labeling with tetracycline and alizarine red S. Conchal growth was particularly rapid in the pigs during the first 2 weeks of life. From the 3rd week, growth of the nasal ventral concha became slower. For a given age, the slow growing zone spread in the rostrocaudal direction. The transversely directed growth of the nasal ventral concha resulted in the optimal filling of the nasal cavities.

A reexamination of the effects of high rearing temperature on the nonolfactory turbinates of rats.

The nasoturbinates and maxilloturbinates have previously been reported to be completely resorbed in Wistar rats reared at 32-33 degrees C from 3 weeks to 6 months of age. The phenomenon was reinvestigated for the first time in the experiments reported here, with dramatically different results. Rats reared at 33 degrees C and 53% relative humidity proved to have naso- and maxilloturbinates of almost the same size as rats reared at 21 degrees C. After effects of skull and rostral size on turbinate size had been statistically removed, rearing temperature proved not to be important in explaining differences in turbinate widths or turbinate separation, but temperature and sex had significant interactive effects on turbinate lengths. Reasons why the turbinates were completely lost in the previous study but largely retained in the present study are unclear and probably subtle, given that procedures in the two studies were closely similar. Loss of the nonolfactory turbinates is demonstrably not a consistent response--adaptive or otherwise--to rearing under hot conditions, and probably factors in addition to temperature are critical to turbinate development.