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The cardiovascular system and respiratory organs in animals are interconnected, they perform extremely important functions for the vital activity of the organism, the main of which is gas exchange. Therefore, the study of the cardiovascular system and respiratory organs is an urgent issue of the present. The aim of the study was to morphologically evaluate the macro- and histological structures of the heart and lungs of the domestic dog. Comprehensive morphological methods of research were used: histological, anatomical, organ, histo-, cytometric, and statistical, which provided new data on the peculiarities of macro-, histo-, and cytomorphometric characteristics of the morphological structures of the heart and lungs. The dog heart has a rounded shape, its absolute weight is 167.58±9.46 g (without epicardial fat – 154.22±8.04 g), relative weight – 0.72±0.005%. It was found that cardiomyocytes of the left ventricle had the largest volume, the right ventricle – the smallest, and atrial cardiomyocytes – the smallest. At the same time, the nuclearcytoplasmic ratio of cardiomyocytes of the left ventricle is 0.0224±0.0076, the cardiomyocytes of the right ventricle have a greater value – 0.0275±0.0081 and the atrial cardiomyocytes have the highest value – 0.0367±0.0105. Such ambiguous cytometric parameters of cardiomyocytes are associated with the morphological and functional activity of the myocardial ventricular muscle tissue and its functional features inherent in spontaneous and rhythmic contractions, which result in blood flow through a closed system of vessels. The absolute weight of the domestic dog’s lungs is 201.3±18.4 g, the relative weight is 1.21±0.14%, the ratio of the absolute weight of the left to the right lung is 1:1.33. According to the asymmetry coefficient (1.37:1), the lungs of dogs are of the narrowed-elongated type. The connective tissue stroma of the lungs occupies 59.62±3.4%, the respiratory part – 40.38±2.6%. The data on the morphology of the heart and lungs of the domestic dog, including the results of the study of the macro- and microscopic structure of the organs under investigation, which are presented in the publication, are of great importance for histology and comparative anatomy, and also make a significant contribution to clinical veterinary medicine

The symmetry of the right and left bronchi, proposed in a previous comparative anatomical study as the basic model of the mammalian bronchial tree, was examined to determine if it applied to the embryonic human bronchial tree. Imaging data of 41 human embryo specimens at Carnegie stages (CS) 16–23 (equivalent to 6–8 weeks after fertilization) belonging to the Kyoto collection were obtained using phase‐contrast X‐ray computed tomography. Three‐dimensional bronchial trees were then reconstructed from these images. Bronchi branching from both main bronchi were labeled as dorsal, ventral, medial, or lateral systems based on the branching position with numbering starting cranially. The length from the tracheal bifurcation to the branching point of the labeled bronchus was measured, and the right‐to‐left ratio of the same labeled bronchus in both lungs was calculated. In both lungs, the human embryonic bronchial tree showed symmetry with an alternating pattern of dorsal and lateral systems up to segmental bronchus B9 as the basic shape, with a more peripheral variation. This pattern is similar to that described in adult human lungs. Bronchial length increased with the CS in all labeled bronchi, whereas the right‐to‐left ratio was constant at approximately 1.0. The data demonstrated that the prototype of the human adult bronchial branching structure is formed and maintained in the embryonic stage. The morphology and branching position of all lobar bronchi and B6, B8, B9, and the subsegmental bronchus of B10 may be genetically determined. On the other hand, no common structures between individual embryos were found in the peripheral branches after the subsegmental bronchus of B10, suggesting that branch formation in this region is influenced more by environmental factors than by genetic factors. [ABSTRACT FROM AUTHOR]

The demand for respiratory disease and dynamic breathing studies has continuously driven researchers to update the pulmonary bronchial tree’s morphology model. This study aims to construct a bronchial tree morphology model efficiently and effectively with practical algorithms. We built a performance index system using failure branch rate, volume ratio, and coefficient of variation of terminal volumes to evaluate the model performance. We optimized the parameter settings and found the best options to build the morphology model, and we constructed a 14th-generation bronchial tree model with a decent performance index. The dimensions of our model closely matched published data from anatomic in vitro measurements. The proposed model is adjustable and computable and will be used in future dynamic breathing simulations and respiratory disease studies. [ABSTRACT FROM AUTHOR]

Three-dimensional numerical simulations of the air flow in the full human bronchial tree in situations of obstructive and chronic pulmonary diseases are performed. Based on the previously developed three-dimensional analytical model of the lower respiratory airways, the air distributions in the lungs (from the trachea to alveoli) in situations with lung injuries and bronchial asthma are calculated. Breathing modeling is based on a numerical technique of step-by-step computations, which allows one to avoid the loss of solution accuracy caused by the difference in the bronchus scales; moreover, the time needed to calculate the air flow in the lungs can be reduced by several times by using this technique. [ABSTRACT FROM AUTHOR]

Respiratory viral infections, such as SARS‐CoV‐2 or influenza, can lead to impaired mucociliary clearance in the bronchial tree due to increased mucus viscosity and its hyper‐secretion. We develop in this work a mathematical model to study the interplay between viral infection and mucus motion. The results of numerical simulations show that infection progression can be characterized by three main stages. At the first stage, infection spreads through the most part of mucus producing airways (about 90% of the length) without significant changes in mucus velocity and thickness layer. During the second stage, when it passes through the remaining generations, mucus viscosity increases, its velocity drops down, and it forms a plug. At the last stage, the thickness of the mucus layer gradually increases because mucus is still produced but not removed by the flow. After some time, the thickness of the mucus layer in the small airways becomes comparable with their diameter leading to their complete obstruction. [ABSTRACT FROM AUTHOR]

Introduction: The aspiration and ingestion of a molar during its extraction is a rare accident, so there is not enough information about the reported cases. The objective of this study is to carry out a systematic review, analyze the articles on intraoperative dental aspiration and intake, and propose an algorithm for the management of this complication. Materials and methods: A systematic review was carried out following the PRISMA criteria in the PubMed database in January 2023 with the following limitations: studies conducted in humans; English language; reports of aspiration and swallowing of teeth during dental extraction, age was not limited. Exclusion criteria: studies of aspiration and ingestion of foreign bodies that do not involve teeth. Results: A total of 5 articles were obtained with 5 reported cases of aspiration. There were no reports associated with the ingestion of a tooth. The most prevalent sex was male, with all cases reported in men, the average age was 24.4 years. The imaging studies of choice were chest radiography and computed tomography. The right bronchus was the most prevalent location site. The first line treatment was bronchoscopy, followed by tracheotomy and thoracotomy. Conclusion: Tooth extraction is a common surgical procedure, so it is essential to be careful in the event of possible complications such as intraoperative aspiration or tooth ingestion. Tooth aspiration can be a life-threatening complication, so prompt management is important. The proposed algorithm allows adequate management for aspiration and swallowing of teeth.

Background: Stereotactic body radiation therapy (SBRT) of central lung tumors with photon or proton therapy has a risk of increased toxicity. Treatment planning studies comparing accumulated doses for state‐of‐the‐art treatment techniques, such as MR‐guided radiotherapy (MRgRT) and intensity modulated proton therapy (IMPT), are currently lacking. Purpose: We conducted a comparison of accumulated doses for MRgRT, robustly optimized non‐adaptive IMPT, and online adaptive IMPT for central lung tumors. A special focus was set on analyzing the accumulated doses to the bronchial tree, a parameter linked to high‐grade toxicities. Methods: Data of 18 early‐stage central lung tumor patients, treated at a 0.35 T MR‐linac in eight or five fractions, were analyzed. Three gated treatment scenarios were compared: (S1) online adaptive MRgRT, (S2) non‐adaptive IMPT, and (S3) online adaptive IMPT. The treatment plans were recalculated or reoptimized on the daily imaging data acquired during MRgRT, and accumulated over all treatment fractions. Accumulated dose‐volume histogram (DVH) parameters of the gross tumor volume (GTV), lung, heart, and organs‐at‐risk (OARs) within 2 cm of the planning target volume (PTV) were extracted for each scenario and compared in Wilcoxon signed‐rank tests between S1 & S2, and S1 & S3. Results: The accumulated GTV D98% was above the prescribed dose for all patients and scenarios. Significant reductions (p < 0.05) of the mean ipsilateral lung dose (S2: –8%; S3: –23%) and mean heart dose (S2: –79%; S3: –83%) were observed for both proton scenarios compared to S1. The bronchial tree D0.1cc was significantly lower for S3 (S1: 48.1 Gy; S3: 39.2 Gy; p = 0.005), but not significantly different for S2 (S2: 45.0 Gy; p = 0.094), compared to S1. The D0.1cc for S2 and S3 compared to S1 was significantly (p < 0.05) smaller for OARs within 1–2 cm of the PTV (S1: 30.2 Gy; S2: 24.6 Gy; S3: 23.1 Gy), but not significantly different for OARs within 1 cm of the PTV. Conclusions: A significant dose sparing potential of non‐adaptive and online adaptive proton therapy compared to MRgRT for OARs in close, but not direct proximity of central lung tumors was identified. The near‐maximum dose to the bronchial tree was not significantly different for MRgRT and non‐adaptive IMPT. Online adaptive IMPT achieved significantly lower doses to the bronchial tree compared to MRgRT. [ABSTRACT FROM AUTHOR]

Respiratory organs and cardiovascular system are interconnected and perform extremely vital functions of the organism, the main goals being performing gas exchange with the environment and emitting carbon dioxide produced in the organism into the environment. Therefore, we carried out comparative histo- and cytomorphometric evaluation of morphological structures of the heart and lungs of cattle, sheep and horses. Using complex methods of research, we determined specifics of microscopic structure and histometric parameters of parenchyma of the lungs and myocardium of the ventricles of the hearts of clinically healthy animals in species aspect – cattle, sheep and horses. The studies revealed that the histoarchitectonics of the studied animals were similar in structure, characteristic of other species of agricultural mammals, and distinct morphometric peculiarities of their histostructures. The study indicated that the respiratory zone of the lungs is most developed in horses. This parameter was lower in ruminants – cattle and sheep. Connective tissue septum of parenchyma of lungs was better expressed in cattle and sheep, and less in horses. At the same time, mean volume of lung alveoli in clinically healthy animals varied: being highest in horses – 699 ± 106 thou µm3, then cattle – 337 ± 43 thou µm3 and sheep – 158 ± 37 thou µm3. Such variation in histometric parameters of parenchyma of the lungs in experimental animals indicates adaptive specifics of the organism of animals in terms of living conditions. Therefore, the respiratory zone was most developed in the lungs of horses, animals that experience significant physical and physiological load on corresponding organs and systems. As a result of histometric studies of myocardium, we determined patterns of sizes of thickness of its cardiomyocytes and volume of their nuclei. We determined that in myocardium of the heart ventricles, in the same microscope field of view, cardiomyocytes of varying thicknesses occur. At the same time, thickness of cardiomyocytes, their mean volume of nuclei in the ventricle myocardium were expressed the most in cattle, then in horses and sheep, and their histometric parameters in myocardium of the left ventricle of the heart in the experimental animals were higher than in the right one. Therefore, thickness of cardiomyocytes of the left ventricle in cattle equaled 14.06 ± 0.41 µm, and volume of nuclei of cardiomyocytes respectively 124.55 ± 7.99 µm3. Similar changes in such parameters of histometry were found in sheep and horses. We attribute such varying histometric parameters of the thickness of cardiomyocytes and volume of their nuclei in myocardium of the left ventricle of the heart in experimental animals, compared with such parameters in the right ventricle, to the activities of the ventricles (the left one generally functions as a pump, right one – as a volumetric) and functional specifics of this myocardium tissue, which is capable of spontaneous rhythmic contractions, resulting in blood flow in the vessels: cardiomyocytes of the left ventricle carry greater load, promoting blood flow in vessels of greater (somatic) blood circulation, respectively cardiomyocytes of the right ventricle – less load, promoting blood flow in vessels of lesser (pulmonary) blood circulation.

Respiratory organs and cardiovascular system are interconnected and perform extremely vital functions of the organism, the main goals being performing gas exchange with the environment and emitting carbon dioxide produced in the organism into the environment. Therefore, we carried out comparative histo- and cytomorphometric evaluation of morphological structures of the heart and lungs of cattle, sheep and horses. Using complex methods of research, we determined specifics of microscopic structure and histometric parameters of parenchyma of the lungs and myocardium of the ventricles of the hearts of clinically healthy animals in species aspect – cattle, sheep and horses. The studies revealed that the histoarchitectonics of the studied animals were similar in structure, characteristic of other species of agricultural mammals, and distinct morphometric peculiarities of their histostructures. The study indicated that the respiratory zone of the lungs is most developed in horses. This parameter was lower in ruminants – cattle and sheep. Connective tissue septum of parenchyma of lungs was better expressed in cattle and sheep, and less in horses. At the same time, mean volume of lung alveoli in clinically healthy animals varied: being highest in horses – 699 ± 106 thou µm³, then cattle – 337 ± 43 thou µm³ and sheep – 158 ± 37 thou µm³ . Such variation in histometric parameters of parenchyma of the lungs in experimental animals indicates adaptive specifics of the organism of animals in terms of living conditions. Therefore, the respiratory zone was most developed in the lungs of horses, animals that experience significant physical and physiological load on corresponding organs and systems. As a result of histometric studies of myocardium, we determined patterns of sizes of thickness of its cardiomyocytes and volume of their nuclei. We determined that in myocardium of the heart ventricles, in the same microscope field of view, cardiomyocytes of varying thicknesses occur. At the same time, thickness of cardiomyocytes, their mean volume of nuclei in the ventricle myocardium were expressed the most in cattle, then in horses and sheep, and their histometric parameters in myocardium of the left ventricle of the heart in the experimental animals were higher than in the right one. Therefore, thickness of cardiomyocytes of the left ventricle in cattle equaled 14.06 ± 0.41 µm, and volume of nuclei of cardiomyocytes respectively 124.55 ± 7.99 µm³ . Similar changes in such parameters of histometry were found in sheep and horses. We attribute such varying histometric parameters of the thickness of cardiomyocytes and volume of their nuclei in myocardium of the left ventricle of the heart in experimental animals, compared with such parameters in the right ventricle, to the activities of the ventricles (the left one generally functions as a pump, right one – as a volumetric) and functional specifics of this myocardium tissue, which is capable of spontaneous rhythmic contractions, resulting in blood flow in the vessels: cardiomyocytes of the left ventricle carry greater load, promoting blood flow in vessels of greater (somatic) blood circulation, respectively cardiomyocytes of the right ventricle – less load, promoting blood flow in vessels of lesser (pulmonary) blood circulation. [ABSTRACT FROM AUTHOR]

The bronchial tree plays a main role in the human respiratory system because the air distribution throughout the lungs and gas exchange with blood occur in the airways whose dimensions vary from several centimeters to micrometers. Organization of about 60,000 conducting airways and 33 million respiratory airways in a limited space results in a complex structure. Due to this inherent complexity and a high number of airways, using target-oriented dimensional reduction is inevitable. In addition, there is no general reduced-order model for various types of problems. This necessitates coming up with an appropriate model from a variety of different reduced-order models to solve the desired problem. Lumped formulation, trumpet, or typical path model of whole or parts of bronchial tree are frequently used reduced-order models. On the other hand, using any of these models results in underestimation of flow heterogeneity leading to inaccurate prediction of the systems whose mechanisms depend on the fluid heterogeneity. In this study, a simple robust model combining mechanistic and non-mechanistic modeling approaches of the bronchial tree is proposed which overcomes the limitations of the previous reduced-order models and gives the same results of a detailed mechanistic model for the first time. This model starts from an accurate multi-branching model of conducting and respiratory airways (i.e., the base model) and suggests a proxy model of conducting airway and reduced-order model of respiratory airways based on the base model to significantly reduce computational cost while retaining the accuracy. The combination of these models suggests various reduced-order surrogate models of the human bronchial tree for different problems. The applications and limitations of each reduced-order model are also discussed. The accuracy of the proposed model in the prediction of fluid heterogeneity has been examined by the simulation of multi-breath inert gas washout because the alveolar slope is the reflection of fluid heterogeneity where the computational time decreases from 121 h (using the base model) to 4.8 s (using the reduced-order model). A parallel strategy for solving the equations is also proposed which decreases run time by 0.18 s making the model suitable for real-time applications. Furthermore, the ability of the model has been evaluated in the modeling of asthmatic lung as an instance of abnormal lungs, and in the modeling of O2–CO2 exchange as an instance of nonlinear reacting systems. The results indicate that the proposed model outperforms previous models based on accuracy, robustness, and run time. [ABSTRACT FROM AUTHOR]

The pulsating airflow through human bronchial tree is of great significance for understanding its function and morphology. Fractal theory and numerical simulation are applied in this paper to study the global and local flow characteristics in the bronchial tree under unstable conditions. First, the pulsating flow impedance of fractal bronchial tree is derived, and the structure of bronchial tree is optimized by minimizing flow impedance. It has been shown that the optimal structure depends on the physical law governing the airflow. The optimized diameter ratio between parent and daughter branches for pulsating flow is different from Murray's law, and the fractal dimension for branch diameter lies in 2 and 3. Afterwards, the local pulsating flow field by three-dimensional (3D) numerical simulation on a symmetrical bronchial model is compared with the global flow characteristics by fractal analysis. The numerical results show that asymmetrical airflow characteristics can be found at high Reynolds number, and the velocity distribution of the main bronchus is more irregular and the turbulence phenomenon is more evident. This work can help to understand the association between function and structure of the bronchial tree, and it may shed light on the physical mechanisms and drugs targeting of pulmonary disease. [ABSTRACT FROM AUTHOR]

Abstract Background Bronchoscopy involves exploration of a three-dimensional (3D) bronchial tree environment using just two-dimensional (2D) images, visual cues and haptic feedback. Sound knowledge and understanding of tracheobronchial anatomy as well as ample training experience is mandatory for technical mastery. Although simulated modalities facilitate safe training for inexperienced operators, current commercial training models are expensive or deficient in anatomical accuracy, clinical fidelity and patient representation. The advent of Three-dimensional (3D) printing technology may resolve the current limitations with commercial simulators. The purpose of this report is to develop and test the novel multi-material three-dimensional (3D) printed airway models for bronchoscopy simulation. Methods Using material jetting 3D printing and polymer amalgamation, human airway models were created from anonymized human thoracic computed tomography images from three patients: one normal, a second with a tumour obstructing the right main bronchus and third with a goitre causing external tracheal compression. We validated their efficacy as airway trainers by expert bronchoscopists. Recruited study participants performed bronchoscopy on the 3D printed airway models and then completed a standardized evaluation questionnaire. Results The models are flexible, life size, anatomically accurate and patient specific. Five expert respiratory physicians participated in validation of the airway models. All the participants agreed that the models were suitable for training bronchoscopic anatomy and access. Participants suggested further refinement of colour and texture of the internal surface of the airways. Most respondents felt that the models are suitable simulators for tracheal pathology, have a learning value and recommend it to others for use in training. Conclusion Using material jetting 3D printing to create patient-specific anatomical models is a promising modality of simulation training. Our results support further evaluation of the printed airway model as a bronchoscopic trainer, and suggest that pathological airways may be simulated using this technique.

Although left/right differences in a configuration of the pulmonary artery (PA) and its branches are well known, there is little information as to when and how such differences are established. Examination of serial sagittal sections of 25 embryos and fetuses at 6–7 weeks of gestation demonstrated that, at O'Rahilly stages 18–20, the right earliest first branch of PA originated in the anterior side of the upper lobar bronchus and overlay the upper bronchi, in contrast to the left branch which was located posteriorly and constricted medially by the upper posterior bronchus B1 + 2b. The right earliest branch was most likely to correspond to the future superior trunk, while the left branch might be a lingual artery. At stages 21–23, the upper posterior parenchyma was still underdeveloped in the left lung, since the ductus arteriosus and the left common cardinal vein seemed to make the left upper thoracic cavity narrow. Conversely, in the right lung, the thick S2 seemed to require a double arterial supply from both the superior and inferior arterial trunks. On the left, A3 originated at the lung apex and took a long descending course along the lung anterior surface. This high position of A3 might soon be corrected by an increased volume of S3. Overall, in contrast to the lower and middle lobes, early‐developed branches of the PA did not accompany upper segmental and subsegmental bronchi. A mechanism "differential growth" seemed to explain how to correct the fetal morphology to provide the adult morphology with variations. [ABSTRACT FROM AUTHOR]

Redistribution of flow in the bronchial tree is an important factor that enhances gas exchange in the lungs, especially, in diseased lungs. The bifurcated bronchial tree is like an electric network in series and parallel. A lumped-model of parallel system for constant flow rate is solved analytically to demonstrate the intrinsic characteristics and the dynamic behavior of the system. Inertial and capacitive time constants are calculated for 19th generation airways of human lung to control the solution. The investigation revealed that (i) higher inertial force takes more time to maximize the inertial flow to steady state and more time to minimize the resistive flow to steady state and (ii) the compliant effect is negligible for a relatively higher inertial time constant, tL > 6s on the same experimental conditions. [ABSTRACT FROM AUTHOR]

The complex flow field in the three‐dimensional internal passages of a model human bronchial tree is studied computationally. Up to five generations of branches, both in‐plane and out‐of‐plane configurations, two velocity profiles and varying inlet Reynolds number are considered. There exists substantial non‐uniformity of the fluid dynamic features (e.g. velocity field, pressure field, mass flow distribution or viscous dissipation) over any longitudinal plane or cross‐sectional plane of a particular branch as well as that between different branches of any generation. The flow asymmetry is explained here by attributing the fluid dynamics to three important features ‐ curvature of flow path, flow division at bifurcations and inertia of the flow. A synthesis of the present comprehensive study leads to the generalization that the out‐of‐plane configuration fosters greater degree of uniformity in the mass flow distributions in the various branches of any generation, but gives rise to greater flow non‐uniformity on any particular cross‐sectional plane as compared to the in‐plane configuration. The out‐of‐plane configuration also causes greater secondary flow and greater loss in total pressure in the network. The effectiveness of previously developed modular computational approaches is assessed through separate simulations for networks comprising two, three, four and five generations (containing 3, 7, 15 and 31 branches respectively). The inadequacy of Hagen‐Poiseuille type 1D model is demonstrated ‐ it can neither predict the flow asymmetry (captured by the 3D computations) nor determine the overall magnitude of loss in total pressure. [ABSTRACT FROM AUTHOR]

We encountered a fetal pig with eventration of the diaphragm and pulmonary hypoplasia accompanied by phrenic nerve agenesis. The fetal pig was female measuring 34 cm in crown-rump length and about 1500 g in body weight. The diaphragm was a complete continuous sheet, but comprised a translucent membrane with residual muscular tissue only at the dorsolateral area of the right leaf of the diaphragm. The left leaf protruded extraordinarily toward the thoracic cavity. The left phrenic nerve was completely absent, while there was a slight remnant of the right phrenic nerve that supplied the dorsolateral muscular area of the right leaf. Both lungs were small, and the number of smaller bronchioles arising from the bronchioles was decreased to about half of that of the normal lung. Additionally, the right and left subclavius muscles and nerves could not be identified. These findings imply that the diaphragm, the subclavius muscle and nerves innervating them comprise a developmental module, which would secondarily affect lung development. It is considered that the present case is analogous to the animal model of congenital eventration of the diaphragm in humans. [ABSTRACT FROM AUTHOR]

Background Bronchus-associated lymphoid tissue (BALT), distributed in the bronchial mucosa, plays a critical role in maintaining the mucosal immune homeostasis of the lower respiratory tract. The bronchial tree is a functional structure for gas exchange with the outside environment and maintains basic lung morphology. Methods To explore the structural and distributive characteristics of BALT in Bactrian camels, twelve healthy adult Bactrian camels were divided into two groups (six in each group). The lungs, bronchial tree and BALT were observed and analysed systematically through anatomical and histological methods. Results The results showed that Bactrian camel lungs were constituted by the left cranial lobe, left caudal lobe, right cranial lobe, right caudal lobe and accessory lobe, but lacked the middle lobe. The cranial lobe was narrow and small, the caudal lobe was extremely developed (almost four times the cranial lobe in size), and the accessory lobe was smaller than the cranial lobe; the bronchial tree, an unequal dichotomy with a tracheobronchial branch, was composed of dorsal, ventral, lateral and medial bronchiole systems. Isolated lymphoid follicles (the chief type) and aggregates of lymphoid follicles revealed two types of BALT, and germinal centres, follicle-associated epithelium and high endothelial venules could be observed in some well-developed BALT. Additionally, BALT was scattered along the bronchial tree in the entire lung, and the density increased from the trachea to the lower graded branches (densest in the bronchioles) and then decreased, with the occasional location around respiratory bronchioles or among the pulmonary mesenchyme. In the conducting portion, BALT was primarily located in the mucosa lamina propria but was also found in the submucosa, under the muscular layer, and around the submucosal glands and cartilage. Conclusion The results demonstrated that the lung morphology of Bactrian camels was similar to that of horses, but the bronchial branches were more closely related to those of ruminants. These characteristics were in accordance with the morphological and structural variation regularity of lungs with species evolution. BALT was mainly scattered in the conducting portion, and bronchioles, as the final “checkpoint” in the surveillance, capture and recognition of antigens before pulmonary exchange, were the pivotal locational position of BALT. However, BALT at different depths of the bronchial wall of the conducting portion might be at different developmental stages. Our study provided evidence for further insight into the mucosal immunomodulatory mechanism of BALT in the respiratory system of Bactrian camels.

The demand for respiratory disease and dynamic breathing studies has continuously driven researchers to update the pulmonary bronchial tree's morphology model. This study aims to construct a bronchial tree morphology model efficiently and effectively with practical algorithms. We built a performance index system using failure branch rate, volume ratio, and coefficient of variation of terminal volumes to evaluate the model performance. We optimized the parameter settings and found the best options to build the morphology model, and we constructed a 14th-generation bronchial tree model with a decent performance index. The dimensions of our model closely matched published data from anatomic in vitro measurements. The proposed model is adjustable and computable and will be used in future dynamic breathing simulations and respiratory disease studies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Liu, Qiu, Li, Chen, Kang and Ruan.)

A 59-year old woman presented with hemoptysis of thick blood clots and fever of two days duration. Her medical history included sarcoidosis for which she was on chronic steroids. Computed tomography imaging revealed stage IV sarcoidosis with diffuse cystic and fibrotic changes bilaterally, worse in the right lung. She underwent bronchoscopy to attempt to localize a source but none was clearly found; no biopsies were performed. Immediately post-procedure she developed massive hemoptysis with hypoxia leading to cardiopulmonary arrest. She was intubated and stabilized with the spontaneous cessation of her bleeding. Immediate angiography revealed no active extravasation, but localized embolization was performed on the right main and right accessory bronchial arteries because these appeared hypertrophied and irregular. Two days later, she again developed spontaneous massive hemoptysis leading to cardiopulmonary arrest. Manual ventilation through the endotracheal tube became impossible. Immediate bronchoscopy identified a blood clot extending from the main carina into the left main stem bronchus. This was removed with a cryoprobe and ventilation could then be achieved easily. Examination of the blood clot demonstrated it to be a cast of the proximal left bronchial tree. Despite the return of spontaneous circulation via resuscitative efforts, the patient developed acute respiratory distress syndrome and later expired.

The vertebrate respiratory system is challenging to study. The complex relationship between the lungs and adjacent tissues, the vast structural diversity of the respiratory system both within individuals and between taxa, its mobility (or immobility) and distensibility, and the difficulty of quantifying and visualizing functionally important internal negative spaces have all impeded descriptive, functional, and comparative research. As a result, there is a relative paucity of three-dimensional anatomical information on this organ system in all vertebrate groups (including humans) relative to other regions of the body. We present some of the challenges associated with evaluating and visualizing the vertebrate respiratory system using computed and micro-computed tomography and its subsequent digital segmentation. We discuss common mistakes to avoid when imaging deceased and live specimens and various methods for merging manual and threshold-based segmentation approaches to visualize pulmonary tissues across a broad range of vertebrate taxa, with a particular focus on sauropsids (reptiles and birds). We also address some of the recent work in comparative evolutionary morphology and medicine that have used these techniques to visualize respiratory tissues. Finally, we provide a clinical study on COVID-19 in humans in which we apply modeling methods to visualize and quantify pulmonary infection in the lungs of human patients., (© 2023 American Association for Anatomy.)

The common marmoset (Callithrix jacchus) are small primates belonging to the family Cebidae, subfamily Callitrichinae and are the most well-known and common in adaptation to captivity. The scarcity of data in the literature on the anatomy of these marmosets and wild animals hinders the application of appropriate anesthetic and surgical procedures and therapeutics. In order to understand the anatomic variations in the lobation and bronchopulmonary segmentation the lungs were dissected from nine adult common marmoset (Callithrix jacchus) corpses, five males and four females. In the marmosets, the right lung presented cranial lobe, middle lobe, caudal lobe and accessory lobe while the left lung presented cranial and caudal lobes. The fissures were very pro-eminent in both the lungs. The main right bronchus emitted independent branches, one for each lobe, and it followed in a straight line in the caudal lobe as a continuation of this bronchus and the same was observed in the main left bronchus. The bronchopulmonary segmentation in the right lung ranged from one to five branches in the cranial lobe; the middle lobe had a single branch; the caudal lobe had three to five branches and the accessory lobe had three branches. In the left lung the cranial lobe bronchopulmonary segmentation ranged from one to five branches while in the caudal lobe it was three to four branches. [ABSTRACT FROM AUTHOR]

High-fidelity simulations of the complete airway tree are still largely beyond current computational capabilities. Towards large-scale simulations of the human lung, the current study introduces a numerical methodology to predict particle deposition in a simplified approximation of the deep lung during a full breathing cycle. The geometrical model employed consists of an idealised bronchial tree that represents generations 10 to 19 of the conducting zone and a heterogeneous acinar model created using a space-filling algorithm. The computational cost of the coupled simulation is reduced by taking advantage of the flow similarity across the central conducting regions in order to decompose the bronchial tree into representative subunits. Topological information is used to account for the correct gravitational force on the particles in the representative bifurcations, emulating their transport characteristics in the actual bronchial tree. Eventually, airflow and particle transport are simulated in a single representative bifurcation and a single acinar model, resulting in great savings in computational cost. An Eulerian-Lagrangian approach has been used for solving the flow and particle equations during sinusoidal breathing in the decomposed domain. The resulting deposition estimates agree rather well with the known deposition trends reported in the literature, while offering additional insights. For 1 − 5 μm particles, deposition during exhalation is comparable to deposition upon inhalation, suggesting the use of breath-hold maneuvers to further increase sedimentation of these particles. Airway orientation relative to gravity was found to have a significant impact on deposition rates, especially for particles above 2 μm and to be higher in the more distal generations, due to the wider range of angles relative to the direction of gravity. In the acinus, particles in the 2 − 5 μm range have a quite high average deposition efficiency that reaches approximately 75% and shows considerable variation (12.4%) due to airway orientation. Finally, a simplified semi-analytical approach is introduced that can lead to even further reduction in computational costs, while incurring only a small loss in accuracy. [ABSTRACT FROM AUTHOR]