scholarly journals A Distinct Difference Between Air and Mucosal Temperatures in Human Respiratory Tract

2021 ◽  
Vol 8 ◽  
Author(s):  
Mehdi Khosravi ◽  
Ruei-Lung Lin ◽  
Ashish P. Maskey ◽  
Subodh Pandey ◽  
An-Hsuan Lin ◽  
...  
Keyword(s):  
Air Temperature ◽  
Close Association ◽  
Sensory Nerves ◽  
Distinct Difference ◽  
Tissue Temperature ◽  
Temperature Sensitive ◽  
Exhaled Breath ◽  
Human Respiratory Tract ◽  
Airway Mucosa ◽  
Exhaled Air

Extensive evidence indicates that several types of temperature-sensitive ion channels are abundantly expressed in the sensory nerves innervating airway mucosa. Indeed, airway temperature is known to play an important role in regulating respiratory functions. However, the actual airway mucosal temperature and its dynamic changes during the respiratory cycle have not been directly measured. In previous studies, airway tissue temperature was often estimated by indirect measurement of the peak exhaled breath temperature (PEBT). In view of the poor thermal conductivity of air, we believe that the airway tissue temperature cannot be accurately determined by the exhaled air temperature, and this study aimed to test this hypothesis. We applied a miniature rapid-response temperature probe to measure directly the mucosal temperatures of trachea, major, lobar, and segmental bronchi in eight human subjects during a bronchoscopy procedure. Unlike the air temperature in the airway lumen, the mucosal temperature in these airway segments remained relatively stable and did not exhibit the phasic changes synchronous with respiratory cycles. The airway mucosal temperature increased progressively from the extra-thoracic trachea (35.7 ± 0.2°C) toward the segmental bronchus (36.9 ± 0.2°C). Most importantly, the temperatures measured directly at the mucosa of all these airway segments were substantially higher than the PEBT (31.7 ± 0.8°C). The recent findings of a close association between an increased PEBT and airway tissue inflammation have revealed the implication and potential of incorporating the PEBT measurement in the future clinical diagnosis of airway inflammation. Therefore, it is imperative to recognize this distinct difference in temperature between airway mucosa and exhaled air.

Exhaled air temperature in asthmatic children: a mathematical evaluation

2009 ◽  
Vol 20 (2) ◽  
pp. 164-171 ◽  
Author(s):  
Massimo Pifferi ◽  
Vincenzo Ragazzo ◽  
Antonino Previti ◽  
Giovanni Pioggia ◽  
Marcello Ferro ◽  
...  
Keyword(s):  
Air Temperature ◽  
Asthmatic Children ◽  
Exhaled Air ◽  
Mathematical Evaluation

Effect of neuropeptides released from sensory nerves on blood flow in the rat airway microcirculation

1992 ◽  
Vol 72 (4) ◽  
pp. 1563-1570 ◽  
Author(s):  
G. Piedimonte ◽  
J. I. Hoffman ◽  
W. K. Husseini ◽  
W. L. Hiser ◽  
J. A. Nadel
Keyword(s):  
Blood Flow ◽  
Substance P ◽  
Regional Blood Flow ◽  
Reference Sample ◽  
Left Ventricular ◽  
Sensory Nerves ◽  
Microvascular Blood Flow ◽  
Systemic Injection ◽  
Airway Mucosa ◽  
Stimulation Of

Stimulation of sensory nerves in the airway mucosa causes local release of the neuropeptides substance P and calcitonin gene-related peptide (CGRP). In this study we used a modification of the reference-sample microsphere technique to measure changes in regional blood flow and cardiac output distribution produced in the rat by substance P, CGRP, and capsaicin (a drug that releases endogenous neuropeptides from sensory nerves). Three sets of microspheres labeled with different radionuclides were injected into the left ventricle of anesthetized F344 rats before, immediately after, and 5 min after left ventricular injections of capsaicin, substance P, or CGRP. The reference blood sample was withdrawn from the abdominal aorta and was simultaneously replaced with 0.9% NaCl at 37 degrees C. We found that stimulation of sensory nerves with a low dose of capsaicin causes a large and selective increase in microvascular blood flow in the extrapulmonary airways. The effect of capsaicin is mimicked by systemic injection of substance P but not by CGRP, suggesting that substance P is the main agent of neurogenic vasodilation in rat airways.

scholarly journals Sec1p and Mso1p C-terminal tails cooperate with the SNAREs and Sec4p in polarized exocytosis

2011 ◽  
Vol 22 (2) ◽  
pp. 230-244 ◽  
Author(s):  
Marion Weber-Boyvat ◽  
Nina Aro ◽  
Konstantin G. Chernov ◽  
Tuula Nyman ◽  
Jussi Jäntti
Keyword(s):  
Close Association ◽  
Adaptor Protein ◽  
Binding Mode ◽  
Snare Complex ◽  
Bimolecular Fluorescence Complementation ◽  
Rab Gtpase ◽  
Temperature Sensitive ◽  
Nucleotide Exchange ◽  
Protein Receptor

The Sec1/Munc18 protein family members perform an essential, albeit poorly understood, function in association with soluble n-ethylmaleimide sensitive factor adaptor protein receptor (SNARE) complexes in membrane fusion. The Saccharomyces cerevisiae Sec1p has a C-terminal tail that is missing in its mammalian homologues. Here we show that deletion of the Sec1p tail (amino acids 658–724) renders cells temperature sensitive for growth, reduces sporulation efficiency, causes a secretion defect, and abolishes Sec1p-SNARE component coimmunoprecipitation. The results show that the Sec1p tail binds preferentially ternary Sso1p-Sec9p-Snc2p complexes and it enhances ternary SNARE complex formation in vitro. The bimolecular fluorescence complementation (BiFC) assay results suggest that, in the SNARE-deficient sso2–1 Δsso1 cells, Mso1p, a Sec1p binding protein, helps to target Sec1p(1–657) lacking the C-terminal tail to the sites of secretion. The results suggest that the Mso1p C terminus is important for Sec1p(1–657) targeting. We show that, in addition to Sec1p, Mso1p can bind the Rab-GTPase Sec4p in vitro. The BiFC results suggest that Mso1p acts in close association with Sec4p on intracellular membranes in the bud. This association depends on the Sec4p guanine nucleotide exchange factor Sec2p. Our results reveal a novel binding mode between the Sec1p C-terminal tail and the SNARE complex, and suggest a role for Mso1p as an effector of Sec4p.

Effect of cold and warm dry air hyperventilation on canine airway blood flow

1987 ◽  
Vol 62 (2) ◽  
pp. 526-532 ◽  
Author(s):  
E. M. Baile ◽  
R. W. Dahlby ◽  
B. R. Wiggs ◽  
G. H. Parsons ◽  
P. D. Pare
Keyword(s):  
Blood Flow ◽  
Left Lung ◽  
Tissue Temperature ◽  
Humid Air ◽  
Dry Air ◽  
Airway Mucosa ◽  
Anesthetized Dogs ◽  
Tracheal Tissue ◽  
Group 2 ◽  
Central Airway

Tracheobronchial blood flow increases with cold air hyperventilation in the dog. The present study was designed to determine whether the cooling or the drying of the airway mucosa was the principal stimulus for this response. Six anesthetized dogs (group 1) were subjected to four periods of eucapnic hyperventilation for 30 min with warm humid air [100% relative humidity (rh)], cold dry air (-12 degrees C, 0% rh), warm humid air, and warm dry air (43 degrees C, 0% rh). Five minutes before the end of each period of hyperventilation, tracheal and central airway blood flow was determined using four differently labeled 15-micron diam radioactive microspheres. We studied another three dogs (group 2) in which 15- and 50-micron microspheres were injected simultaneously to determine whether there were any arteriovenous communications in the bronchovasculature greater than 15 micron diam. After the last measurements had been made, all dogs were killed, and the lungs, including the trachea, were excised and blood flow to the trachea, left lung bronchi, and parenchyma was calculated. Warm dry air hyperventilation produced a consistently greater increase in tracheobronchial blood flow (P less than 0.01) than cold dry air hyperventilation, despite the fact that there was a smaller fall (6 degrees C) in tracheal tissue temperature during warm dry air hyperventilation than during cold dry air hyperventilation (11 degrees C), suggesting that drying may be a more important stimulus than cold for increasing airway blood flow. In group 2, the 15-micron microspheres accurately reflected the distribution of airway blood flow but did not always give reliable measurements of parenchymal blood flow.

scholarly journals Nitric Oxide and Biological Mediators in Pediatric Chronic Rhinosinusitis and Asthma

2019 ◽  
Vol 8 (11) ◽  
pp. 1783 ◽  
Author(s):  
Valentina Agnese Ferraro ◽  
Stefania Zanconato ◽  
Eugenio Baraldi ◽  
Silvia Carraro
Keyword(s):  
Nitric Oxide ◽  
Chronic Rhinosinusitis ◽  
Exhaled Breath Condensate ◽  
Main Body ◽  
Exhaled Breath ◽  
Non Invasive ◽  
Volatile Organic ◽  
Exhaled Air ◽  
Breath Condensate

Background: In the context of the so-called unified airway theory, chronic rhinosinusitis (CRS) and asthma may coexist. The inflammation underlying these conditions can be studied through the aid of biomarkers. Main body: We described the main biological mediators that have been studied in pediatric CRS and asthma, and, according to the available literature, we reported their potential role in the diagnosis and management of these conditions. As for CRS, we discussed the studies that investigated nasal nitric oxide (nNO), pendrin, and periostin. As for asthma, we discussed the role of fractional exhaled nitric oxide (feNO), the role of periostin, and that of biological mediators measured in exhaled breath condensate (EBC) and exhaled air (volatile organic compounds, VOCs). Conclusion: Among non-invasive biomarkers, nNO seems the most informative in CRS and feNO in asthma. Other biological mediators seem promising, but further studies are needed before they can be applied in clinical practice.

Exhaled air temperature as a function of ambient temperature in flying and resting ducks

2006 ◽  
Vol 176 (6) ◽  
pp. 527-534 ◽  
Author(s):  
Sophia Engel ◽  
Raymond H. G. Klaassen ◽  
Marcel Klaassen ◽  
Herbert Biebach
Keyword(s):  
Ambient Temperature ◽  
Air Temperature ◽  
Exhaled Air

Sensory denervation by neonatal capsaicin treatment exacerbates Mycoplasma pulmonis infection in rat airways

1996 ◽  
Vol 270 (3) ◽  
pp. L393-L403 ◽  
Author(s):  
J. J. Bowden ◽  
P. Baluk ◽  
P. M. Lefevre ◽  
T. R. Schoeb ◽  
J. R. Lindsey ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Chronic Inflammation ◽  
Fold Increase ◽  
Nerve Fibers ◽  
Sensory Nerves ◽  
Mycoplasma Pulmonis ◽  
Tracheal Mucosa ◽  
Airway Mucosa ◽  
Plasma Leakage ◽  
Mucosal Thickening

Mycoplasma pulmonis infection in rats results in life-long disease, characterized by chronic inflammation of the airway mucosa with widespread accumulation of lymphoid tissue, mucous cell hyperplasia, and mucosal thickening. In addition, there is angiogenesis and increased sensitivity of mucosal blood vessels to substance P (SP), so tachykinins released from sensory nerve fibers cause an abnormally large amount of plasma leakage. We sought to learn whether the sensory nerves influence the severity of the chronic inflammatory response of M. pulmonis infection. Our strategy was to destroy the nerves by capsaicin pretreatment at birth, infect the rats with M. pulmonis at 8 wk of age, and then study the animals 6 wk later. We found that capsaicin pretreatment increased the severity of the infection, exaggerated the pathological changes in the tracheal mucosa, and increased the amount of SP-induced plasma leakage, as quantified with Monastral blue. The thickness of the tracheal mucosa in these infected rats was 80% greater than in their vehicle-pretreated counterparts and 200% greater than in the pathogen-free controls. The area density of Monastral blue-labeled blood vessels averaged 20% in the infected rats pretreated with capsaicin, which represented a 40-fold increase over the leakage in the pathogen-free group. By comparison, the amount of Monastral blue labeling was only 13% in rats pretreated with vehicle (P<0.05), which was a 22-fold increase over the corresponding pathogen-free group. The number of SP-immunoreactive nerve fibers was reduced both by neonatal capsaicin and by infection (87 and 63% reductions, respectively); but when the two conditions were combined, their effects were not additive (79% reduction), perhaps because of nerve regrowth. We conclude that destruction of sensory nerves increases the severity of infection- induced chronic inflammation in the airway mucosa, with exaggerated mucosal thickening, angiogenesis, plasma leakage, and nerve remodeling.

Review of the algorithms used in exhaled breath analysis for the detection of diabetes

2022 ◽  
Author(s):  
Anna Paleczek ◽  
Artur Maciej Rydosz
Keyword(s):  
Gas Sensors ◽  
Support Vector ◽  
Exhaled Breath ◽  
Diagnostic Systems ◽  
Exhaled Breath Analysis ◽  
Potential Biomarker ◽  
Exhaled Air ◽  
Medical Diagnostic ◽  
Detection Of Biomarkers ◽  
Intensive Work

Abstract Currently, intensive work is underway on the development of truly noninvasive medical diagnostic systems, including respiratory analysers based on the detection of biomarkers of several diseases including diabetes. In terms of diabetes, acetone is considered as a one of the potential biomarker, although is not the single one. Therefore, the selective detection is crucial. Most often, the analysers of exhaled breath are based on the utilization of several commercially available gas sensors or on specially designed and manufactured gas sensors to obtain the highest selectivity and sensitivity to diabetes biomarkers present in the exhaled air. An important part of each system are the algorithms that are trained to detect diabetes based on data obtained from sensor matrices. The prepared review of the literature showed that there are many limitations in the development of the versatile breath analyser, such as high metabolic variability between patients, but the results obtained by researchers using the algorithms described in this paper are very promising and most of them achieve over 90% accuracy in the detection of diabetes in exhaled air. This paper summarizes the results using various measurement systems, feature extraction and feature selection methods as well as algorithms such as Support Vector Machines, k-Nearest Neighbours and various variations of Neural Networks for the detection of diabetes in patient samples and simulated artificial breath samples.

Frontal eye circuitry, rostral sensory pathways and brain organization in amphioxus larvae: evidence from 3D reconstructions

1996 ◽  
Vol 351 (1337) ◽  
pp. 243-263 ◽  
Keyword(s):  
Close Association ◽  
Anterior Part ◽  
Sensory Nerves ◽  
Morphological Evidence ◽  
Sensory Cells ◽  
Dorsal Cortex ◽  
3D Reconstructions ◽  
Receptor Cells ◽  
Local Circuits ◽  
Cerebral Vesicle

The cells comprising the frontal eye of a 12.5 day amphioxus larva are described based on 3D reconstructions from serial electron micrographs, along with the fibre tracts and more caudal groupings of cells in the nerve cord to which the frontal eye appears to be linked. The frontal eye consists of a pigment cup, two transverse rows of receptor cells, and clusters of neurons whose close association with the medial receptor cells suggests they may function as an integral part of the eye complex. Neurites from both the receptor cells and neurons supply the ventrolateral nerve tracts, which consist mainly of axons arising from sensory cells located at the rostral tip of the larva. A core group of 3—4 rostral fibres on each side innervate two ventral giant cells located just behind the cerebral vesicle in the primary motor centre (PMC). The circuitry suggests these cells may be responsible for triggering the larval startle response. The ventrolateral tracts also include two types of axial dendrite-like fibres: (i) a single unpaired fibre, a forward continuation of the principal dendrite of the left giant cell, which is the main target for synapses from neurons in the frontal eye; and (ii) sets of paired fibres from cells in the tectum, a dorsal cortex-like structure located at the back of the cerebral vesicle through which the dorsal sensory nerves pass in transit to the PMC. Recent behavioural studies show that larvae feed in a hovering posture that maximally shades the frontal eye. They also orient to light in this position. The shape and orientation of the frontal eye suggests it could be responsible for this response. The existence of separate pathways from lateral and medial receptor cells, both directly and indirectly to the PMC, suggests the frontal eye may also be involved in modulating locomotory behaviour during hovering. The visual ‘system’ described here for amphioxus larvae is more like that of vertebrates than has previously been recognized. Specifically: ( i )the medial nerve cells of the frontal eye appear to form local circuits with relay and integrative functions similar to those of the retina, involving cell types that resemble specific retinal interneurons; and (ii) output is directed to a region at the back of the posterior c.v. that resembles the vertebrate midbrain, and which may be its homologue. This region has a dorsal tectum and, like the midbrain, includes the anterior part of a ventral zone of motoneurons and reticulospinal interneurons. The morphological evidence supports the idea that the ‘brain’ of amphioxus is sufficiently like that of vertebrates to provide important clues concerning the basic organization and subdivision of the vertebrate brain.

scholarly journals The alcohol breath test in practice: effects of exhaled volume

2019 ◽  
Vol 126 (6) ◽  
pp. 1630-1635 ◽  
Author(s):  
Joseph C. Anderson ◽  
Michael P. Hlastala
Keyword(s):  
Breath Test ◽  
Alcohol Concentration ◽  
Exhaled Breath ◽  
Average Volume ◽  
Additional Increase ◽  
Flow Rates ◽  
Air Volume ◽  
Breath Alcohol ◽  
Exhaled Air ◽  
Breath Alcohol Concentration

Alcohol breath test (ABT) measurements are sensitive to the volume of the exhaled breath. Although a minimum breath volume is required for a legally acceptable sample, any additional increase in the volume of exhaled air increases the measurement of breath alcohol concentration (BrAC). Using a sample of 115 ABTs collected by police agencies for evidentiary purposes, we studied the influence of exhaled air volume on the measurement of BrAC. The 115 ABTs were performed on 30 different Alcotest 9510s. Each of the tests included paired, time series measurements of exhaled breath flow rates and breath alcohol content. The exhalation flow rates and exhalation times were used to create exhalation volume-BrAC plots. On average, exhaled air volumes were ~50% of the subjects’ age-, height-, race-, and sex-predicted vital capacities (VC). More than 80% of the samples had exhaled air volumes ranging between 30 and 70% of the subject’s predicted VC. Breath volumes for duplicate breath samples were similar. For all breath samples, BrAC increased with exhalation volume, an expected behavior for any very high blood solubility compound such as alcohol. Beyond the legally accepted minimum expiratory volume, BrAC increased, on average, at a rate of 9.2 ± 2.8%/liter air exhaled. As a result, a person who exhales just beyond the minimum volume will have a lower BrAC compared with a person who exhales a full VC. Exhaled volume materially impacts the measurement of an ABT. NEW & NOTEWORTHY Subjects who provide breath samples for evidentiary alcohol breath tests exhale, on average, about half of their predicted vital capacity. Because breath alcohol concentration increases with greater exhaled air volume, subjects who exhale more than average volume will have a greater breath alcohol concentration, whereas subjects who exhale less than average volume will have a lesser breath alcohol concentration. A quantification of air volume impact on breath alcohol concentration is provided.

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