Neti pot irrigation volume filling simulation using anatomically accurate in-vivo nasal airway geometry

Computer fluid dynamics (CFD) has for many years now been employed to study and solve fluid problems in the industry and offers an attractive method for accurately describing systems at a reasonable cost. Computer-aided methods are becoming increasingly important in medicine. Due to a combination of increased computer efficiency and advanced numerical techniques, the realism of these simulations has been enhanced in recent years. Over the past decade, computer-aided design has emerged as a method that is both sufficiently rigorous and efficient to be used for studies of the fluid dynamics in complex airway structures like the nasal airway. Physical experiments in vitro and in vivo are often expensive and time-consuming, and CFD has gained increasing attention as a tool in the design process of devices delivering drugs to the respiratory tract. This paper provides a review of the development of CFD in the studies of nasal airway fluid dynamics, particle and filtering properties in health and disease. Special emphasis is given to studies related to CFD studies used in the development of nasal drug delivery devices. The accuracy and value of CFD for the study of drug delivery design to the nose is reviewed in comparison to experimental results with other methods. Some important challenges when dealing with grid generation and flow simulations in these complex geometries with variable multiphase flow patterns in alternate directions are discussed.

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SARS-CoV-2 spike D614G variant confers enhanced replication and transmissibility

10.1101/2020.10.27.357558 ◽

2020 ◽

Cited By ~ 7

Author(s):

Bin Zhou ◽

Tran Thi Nhu Thao ◽

Donata Hoffmann ◽

Adriano Taddeo ◽

Nadine Ebert ◽

...

Keyword(s):

Mouse Model ◽

Competitive Advantage ◽

Nasal Airway ◽

Airway Epithelial ◽

Founder Effects ◽

Fitness Advantage ◽

Epithelial Cultures ◽

Bottle Neck

AbstractDuring the evolution of SARS-CoV-2 in humans a D614G substitution in the spike (S) protein emerged and became the predominant circulating variant (S-614G) of the COVID-19 pandemic1. However, whether the increasing prevalence of the S-614G variant represents a fitness advantage that improves replication and/or transmission in humans or is merely due to founder effects remains elusive. Here, we generated isogenic SARS-CoV-2 variants and demonstrate that the S-614G variant has (i) enhanced binding to human ACE2, (ii) increased replication in primary human bronchial and nasal airway epithelial cultures as well as in a novel human ACE2 knock-in mouse model, and (iii) markedly increased replication and transmissibility in hamster and ferret models of SARS-CoV-2 infection. Collectively, our data show that while the S-614G substitution results in subtle increases in binding and replication in vitro, it provides a real competitive advantage in vivo, particularly during the transmission bottle neck, providing an explanation for the global predominance of S-614G variant among the SARS-CoV-2 viruses currently circulating.

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Reduction by NG-nitro-L-arginine methyl ester (L-NAME) of antigen-induced nasal airway plasma extravasation in human subjects in vivo

British Journal of Pharmacology ◽

10.1111/j.1476-5381.1995.tb16653.x ◽

1995 ◽

Vol 116 (2) ◽

pp. 1720-1722 ◽

Cited By ~ 10

Author(s):

J.W. Dear ◽

G.K. Scadding ◽

J.C. Foreman

Keyword(s):

Methyl Ester ◽

Human Subjects ◽

Plasma Extravasation ◽

Nasal Airway

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Effect of nasal airway nonlinearities on oscillometric resistance measurements in infants

Journal of Applied Physiology ◽

10.1152/japplphysiol.00128.2020 ◽

2020 ◽

Vol 129 (3) ◽

pp. 591-598

Author(s):

Bence L. Radics ◽

Gergely Makan ◽

Thibault Coppens ◽

Nicolas André ◽

Cyril Page ◽

...

Keyword(s):

Respiratory System ◽

Upper Airway ◽

Nasal Airway ◽

Nonlinearity Error ◽

Flow Acceleration ◽

In Vitro Measurements ◽

3D Printed ◽

Respiratory System Resistance

Oscillometric measurements of respiratory system resistance (Rrs) in infants are usually made via the nasal pathways, which not only significantly contribute to overall Rrs but also introduce marked flow acceleration-dependent distortions. Here, we propose a method for correcting flow acceleration-dependent nonlinearity error based on in vitro measurements in 3D-printed upper airway casts of infants as well as in vivo measurements. This correction can be adapted to estimate Rrs from a single intrabreath oscillometric measurement.

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Kinins are generated in vivo following nasal airway challenge of allergic individuals with allergen.

Journal of Clinical Investigation ◽

10.1172/jci111127 ◽

1983 ◽

Vol 72 (5) ◽

pp. 1678-1685 ◽

Cited By ~ 216

Author(s):

D Proud ◽

A Togias ◽

R M Naclerio ◽

S A Crush ◽

P S Norman ◽

...

Keyword(s):

Nasal Airway

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Fine Structural Changes in the Microvasculature of the Mouse Pinna: Aging and Radiation Injury

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050287 ◽

1974 ◽

Vol 32 ◽

pp. 54-55

Author(s):

S. Phyllis Steamer ◽

Rosemarie L. Devine

Keyword(s):

Structural Changes ◽

Radiation Treatment ◽

Arterial Stenosis ◽

Ultrastructural Changes ◽

Vascular Effects ◽

Microvascular Changes ◽

Surrounding Connective Tissue ◽

Fission Neutrons ◽

Total Body

The importance of radiation damage to the skin and its vasculature was recognized by the early radiologists. In more recent studies, vascular effects were shown to involve the endothelium as well as the surrounding connective tissue. Microvascular changes in the mouse pinna were studied in vivo and recorded photographically over a period of 12-18 months. Radiation treatment at 110 days of age was total body exposure to either 240 rad fission neutrons or 855 rad 60Co gamma rays. After in vivo observations in control and irradiated mice, animals were sacrificed for examination of changes in vascular fine structure. Vessels were selected from regions of specific interest that had been identified on photomicrographs. Prominent ultrastructural changes can be attributed to aging as well as to radiation treatment. Of principal concern were determinations of ultrastructural changes associated with venous dilatations, segmental arterial stenosis and tortuosities of both veins and arteries, effects that had been identified on the basis of light microscopic observations. Tortuosities and irregularly dilated vein segments were related to both aging and radiation changes but arterial stenosis was observed only in irradiated animals.

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