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Lawrence M Witmer - One of the best experts on this subject based on the ideXlab platform.
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ontogeny of the middle ear air sinus system in alligator mississippiensis archosauria crocodylia
PLOS ONE, 2015Co-Authors: David L Dufeau, Lawrence M WitmerAbstract:Modern crocodylians, including Alligator mississippiensis, have a greatly elaborated system of pneumatic Sinuses invading the cranium. These Sinuses invade nearly all the bones of the chondrocranium and several bony elements of the splanchnocranium, but patterns of postnatal paratympanic sinus development are poorly understood and documented. Much of crocodylomorph—indeed archosaurian—evolution is characterized by the evolution of various paratympanic air Sinuses, the homologies of which are poorly understood due in large part to the fact that individual Sinuses tend to become confluent in adults, obscuring underlying patterns. This study seeks to explore the ontogeny of these Sinuses primarily to clarify the anatomical relations of the individual Sinuses before they become confluent and thus to provide the foundation for later studies testing hypotheses of homology across extant and extinct Archosauria. Ontogeny was assessed using computed tomography in a sample of 13 specimens covering an almost 19-fold increase in head size. The paratympanic sinus system comprises two major inflations of evaginated pharyngeal epithelium: the pharyngotympanic sinus, which communicates with the pharynx via the lateral (true) Eustachian tubes and forms the cavum tympanicum proprium, and the median pharyngeal sinus, which communicates with the pharynx via the median pharyngeal tube. Each of these primary inflations gives rise to a number of secondary inflations that further invade the bones of the skull. The primary Sinuses and secondary diverticula are well developed in perinatal individuals of Alligator, but during ontogeny the number and relative volumes of the secondary diverticula are reduced. In addition to describing the morphological ontogeny of this sinus system, we provide some preliminary exploratory analyses of sinus function and allometry, rejecting the hypothesis that changes in the volume of the paratympanic Sinuses are simply an allometric function of braincase volume, but instead support the hypothesis that these changes may be a function of the acoustic properties of the middle ear.
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the paranasal air Sinuses of predatory and armored dinosaurs archosauria theropoda and ankylosauria and their contribution to cephalic structure
Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology, 2008Co-Authors: Lawrence M Witmer, Ryan C RidgelyAbstract:The paranasal air Sinuses and nasal cavities were studied along with other cephalic spaces (brain cavity, paratympanic Sinuses) in certain dinosaurs via CT scanning and 3D visualization to document the anatomy and examine the contribution of the Sinuses to the morphological organization of the head as a whole. Two representatives each of two dinosaur clades are compared: the theropod saurischians Majungasaurus and Tyrannosaurus and the ankylosaurian ornithischians Panoplosaurus and Euoplocephalus. Their extant archosaurian outgroups, birds and crocodilians (exemplified by ostrich and alligator), display a diversity of paranasal Sinuses, yet they share only a single homologous antorbital sinus, which in birds has an important subsidiary diverticulum, the suborbital sinus. Both of the theropods had a large antorbital sinus that pneumatized many of the facial and palatal bones as well as a birdlike suborbital sinus. Given that the suborbital sinus interleaves with jaw muscles, the paranasal Sinuses of at least some theropods (including birds) were actively ventilated rather than being dead-air spaces. Although many ankylosaurians have been thought to have had extensive paranasal Sinuses, most of the snout is instead (and surprisingly) often occupied by a highly convoluted airway. Digital segmentation, coupled with 3D visualization and analysis, allows the positions of the Sinuses to be viewed in place within both the skull and the head and then measured volumetrically. These quantitative data allow the first reliable estimates of dinosaur head mass and an assessment of the potential savings in mass afforded by the Sinuses.
William Lawson - One of the best experts on this subject based on the ideXlab platform.
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ORIGINAL RESEARCH Crista Galli Pneumatization Is an Extension of the Adjacent Frontal Sinuses
2014Co-Authors: P. M. Som, Thomas P Naidich, William LawsonAbstract:BACKGROUND AND PURPOSE: The crista galli is part of the ethmoid bone and, as such, it could be expected that aeration of the crista would come from ethmoid cells. After observing crista pneuma-tization from the frontal Sinuses in several cases, we undertook this study to establish how often crista galli pneumatization came from the frontal Sinuses rather than from the ethmoid complex. MATERIALS AND METHODS: Two hundred consecutive CT scans of the paranasal Sinuses were studied in adult patients to obtain the incidence of crista galli pneumatization and the cell of origin for this phenomenon. A second group of 132 children, 0–7 years of age, was studied to see if any crista galli pneumatization occurred before frontal sinus development. A third group of 79 children, 7–12 years of age, was also studied to see when crista pneumatization occurred in children whose frontal Sinuses had already extended into the squamosal portion of the frontal bone. RESULTS: Of the 200 adult cases, there were 26 patients (13%) with crista galli pneumatization, all from either the left or right frontal Sinuses. In the second group of children 0–7 years of age, there were no cases of crista pneumatization. In the third group of children 7–12 years of age, there were 4 cases of crista galli pneumatization, all from well-developed frontal Sinuses. CONCLUSIONS: Our study indicates that crista galli pneumatization is virtually exclusively from eithe
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crista galli pneumatization is an extension of the adjacent frontal Sinuses
American Journal of Neuroradiology, 2008Co-Authors: E E Park, Thomas P Naidich, William LawsonAbstract:BACKGROUND AND PURPOSE: The crista galli is part of the ethmoid bone and, as such, it could be expected that aeration of the crista would come from ethmoid cells. After observing crista pneumatization from the frontal Sinuses in several cases, we undertook this study to establish how often crista galli pneumatization came from the frontal Sinuses rather than from the ethmoid complex. MATERIALS AND METHODS: Two hundred consecutive CT scans of the paranasal Sinuses were studied in adult patients to obtain the incidence of crista galli pneumatization and the cell of origin for this phenomenon. A second group of 132 children, 0–7 years of age, was studied to see if any crista galli pneumatization occurred before frontal sinus development. A third group of 79 children, 7–12 years of age, was also studied to see when crista pneumatization occurred in children whose frontal Sinuses had already extended into the squamosal portion of the frontal bone. RESULTS: Of the 200 adult cases, there were 26 patients (13%) with crista galli pneumatization, all from either the left or right frontal Sinuses. In the second group of children 0–7 years of age, there were no cases of crista pneumatization. In the third group of children 7–12 years of age, there were 4 cases of crista galli pneumatization, all from well-developed frontal Sinuses. CONCLUSIONS: Our study indicates that crista galli pneumatization is virtually exclusively from either the left or right frontal Sinuses and not from displaced ethmoid complex cells in the frontal recess. This finding may have surgical implications when disease is present in the crista galli.
Christian Von Buchwald - One of the best experts on this subject based on the ideXlab platform.
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colonisation and infection of the paranasal Sinuses in cystic fibrosis patients is accompanied by a reduced pmn response
Journal of Cystic Fibrosis, 2012Co-Authors: Helle Krogh Johansen, Kasper Aanaes, Tania Pressler, K G Nielsen, Jacob Fisker, Marianne Nielsine Skov, Niels Hoiby, Christian Von BuchwaldAbstract:Abstract Background We studied whether the Sinuses might be foci for Pseudomonas aeruginosa lung infection. Methods Endoscopic Sinus Surgery was performed in 78 CF patients; PFGE was used for bacterial genotyping. Material from Sinuses and lungs were Gram-stained to detect biofilms. Immunoglobulins were measured in serum and saliva. Results When P. aeruginosa was cultured simultaneously from the Sinuses and the lungs they were genetically identical in 38 of the 40 patients (95%). In the Sinuses, P. aeruginosa formed biofilms with minimal cellular inflammation, probably because of a significantly higher local production of secretory IgA compared with IgG ( p Conclusions We have shown that P. aeruginosa form biofilm in the Sinuses, which constitute an important bacterial reservoir for subsequent lung infection. The high amount of IgA in the upper airways probably protects P. aeruginosa from the inflammatory immune system, and they can proceed unnoticed into a permanent infectious focus that cannot be eradicated with antibiotics.
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evolution and diversification of pseudomonas aeruginosa in the paranasal Sinuses of cystic fibrosis children have implications for chronic lung infection
The ISME Journal, 2012Co-Authors: Susse Kirkelund Hansen, Oana Ciofu, Helle Krogh Johansen, Kasper Aanaes, Martin Holm Rau, Lars Jelsbak, Lei Yang, Anders Folkesson, Hanne Ostergaard Jarmer, Christian Von BuchwaldAbstract:The opportunistic pathogen Pseudomonas aeruginosa is a frequent colonizer of the airways of patients suffering from cystic fibrosis (CF). Depending on early treatment regimens, the colonization will, with high probability, develop into chronic infections sooner or later, and it is important to establish under which conditions the switch to chronic infection takes place. In association with a recently established sinus surgery treatment program for CF patients at the Copenhagen CF Center, colonization of the paranasal Sinuses with P. aeruginosa has been investigated, paralleled by sampling of sputum from the same patients. On the basis of genotyping and phenotypic characterization including transcription profiling, the diversity of the P. aeruginosa populations in the Sinuses and the lower airways was investigated and compared. The observations made from several children show that the paranasal Sinuses constitute an important niche for the colonizing bacteria in many patients. The paranasal Sinuses often harbor distinct bacterial subpopulations, and in the early colonization phases there seems to be a migration from the Sinuses to the lower airways, suggesting that independent adaptation and evolution take place in the Sinuses. Importantly, before the onset of chronic lung infection, lineages with mutations conferring a large fitness benefit in CF airways such as mucA and lasR as well as small colony variants and antibiotic-resistant clones are part of the sinus populations. Thus, the paranasal Sinuses potentially constitute a protected niche of adapted clones of P. aeruginosa, which can intermittently seed the lungs and pave the way for subsequent chronic lung infections.
Ramazan Albayrak - One of the best experts on this subject based on the ideXlab platform.
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combined sphenoid and frontal sinus aplasia accompanied by bilateral maxillary and ethmoid sinus hypoplasia
British Journal of Radiology, 2005Co-Authors: Alpay Haktanir, Murat Acar, Aylin Yucel, A Aycicek, Bumin Degirmenci, Ramazan AlbayrakAbstract:We describe CT scans of a case with bilateral aplasia of frontal and sphenoid Sinuses with symmetrical hypoplasia of the ethmoid cellules and maxillary Sinuses. This case appears to be first in the English-language literature with these combined findings.
James N Palmer - One of the best experts on this subject based on the ideXlab platform.
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deposition of drugs in the nose and Sinuses with an exhalation delivery system vs conventional nasal spray or high volume irrigation in draf ii iii post surgical anatomy
Rhinology, 2019Co-Authors: P G Djupesland, J C Messina, James N PalmerAbstract:Background Endoscopic sinus surgery is often performed to improve delivery of topical medication into sinus cavities. Intranasal steroids are guideline recommended in post-surgical patients, and experiments with cadavers suggest that surgery improves delivery of drug into Sinuses. Exhalation delivery systems (EDS) use a new mechanism for intranasal delivery and have been shown to reach superior/posterior regions of the nasal cavity better than nasal sprays in unoperated patients. Methods Silicone casts of the nasal cavity and Sinuses from a patient after Draf II, and then Draf III, were made from high-resolution computed tomography (CT) data using 3D printing. Internal surfaces were coated with liquid-sensitive, color-changing gel. Color changes were evaluated following conventional nasal spray delivery (0.1 mL x 2) (Nasonex), EDS delivery (0.1 mL x 2) (XHANCE), and high-volume, low-flow (HVLF) delivery (80 mL) with head tilted either 45° or 90°. Results Conventional nasal spray deposited liquid only in anterior nasal segments. EDS deposited liquid throughout the nasal cavity, in surgically opened ethmoid and maxillary spaces, at entrances of the frontal Sinuses in Draf II geometry, and into frontal Sinuses in Draf III. Tilted 45° HVLF delivery enters the maxillary Sinuses but not the frontal Sinuses or the ethmoid region. At full 90° inclination, HVLF delivery reaches most of the frontal and maxillary Sinuses but not the roof and posterior wall of the ethmoid region. Conclusions HVLF and EDS produced a deep intranasal/intrasinal deposition in the silicone cast compared with conventional nasal spray delivery; both deposited liquid inside the surgically opened Sinuses. HVLF offers the benefit of lavage, whereas EDS may be more efficient and convenient.
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cadaveric validation study of computational fluid dynamics model of sinus irrigations before and after sinus surgery
International Forum of Allergy & Rhinology, 2016Co-Authors: John R Craig, Ngoc Doan, John Y K Lee, Sammy Khalili, Kai Zhao, Nithin D Adappa, James N PalmerAbstract:Background Investigations into the distribution of sinus irrigations have been limited by labor-intensive methodologies that do not capture the full dynamics of irrigation flow. The purpose of this study was to validate the accuracy of a computational fluid dynamics (CFD) model for sinonasal irrigations through a cadaveric experiment. Methods Endoscopic sinus surgery was performed on 2 fresh cadavers to open all 8 Sinuses, including a Draf III procedure for cadaver 1, and Draf IIb frontal sinusotomies for cadaver 2. Computed tomography maxillofacial scans were obtained preoperatively and postoperatively, from which CFD models were created. Blue-dyed saline in a 240-mL squeeze bottle was used to irrigate cadaver Sinuses at 60 mL/second (120 mL per side, over 2 seconds). These parameters were replicated in CFD simulations. Endoscopes were placed through trephinations drilled through the anterior walls of the maxillary and frontal Sinuses, and sphenoid roofs. Irrigation flow into the maxillary, frontal, and sphenoid Sinuses was graded both ipsilateral and contralateral to the side of nasal irrigation, and then compared with the CFD simulations. Results In both cadavers, preoperative and postoperative irrigation flow into maxillary, frontal, and sphenoid Sinuses matched extremely well when comparing the CFD models and cadaver endoscopic videos. For cadaver 1, there was 100% concordance between the CFD model and cadaver videos, and 83% concordance for cadaver 2. Conclusion This cadaveric experiment provided potential validation of the CFD model for simulating saline irrigation flow into the maxillary, frontal, and sphenoid Sinuses before and after sinus surgery.
