Airway resistance measured in liquid-trapped guinea pig lungs by micropuncture

1988 ◽  
Vol 65 (6) ◽  
pp. 2446-2452
Author(s):  
Y. L. Lai ◽  
S. Ganesan ◽  
S. J. Lai-Fook
Keyword(s):  
Guinea Pig ◽  
Airway Resistance ◽  
Close Association ◽  
Maximum Volume ◽  
Liquid Pressure ◽  
Opening Pressure ◽  
Airway Narrowing ◽  
Airway Opening ◽  
Liquid Trapping ◽  
The Relationship

We studied the relationship between bronchoconstriction and the degree of trapping in saline-filled lungs isolated from guinea pigs postmortem after rapid exsanguination. Airway resistance was measured in nine lungs, and in five lungs the site of airway narrowing was located radiographically. Animals were anesthetized with pentobarbital sodium, degassed by O2 absorption, then rapidly exsanguinated when O2 absorption was almost complete. Liquid trapping was assessed from the pressure-volume behaviour measured in saline-filled lungs. During a slow deflation from maximum volume, alveolar liquid pressure (Palv) was measured by the micropipette-servonulling method, airway opening pressure (Pao) by a strain gauge, and flow rate (Q) by weighing a reservoir connected to the airway. Airway resistance (Raw) was calculated at different lung volumes from the relationship: Raw = (Palv-Pao)/Q. In untreated lungs, Raw and fluid trapping were relatively high, and severe bronchoconstriction occurred at the level of the main stem and lobar bronchi. Nifedipine infusion reduced Raw 40-fold and decreased trapping. Raw was further reduced 10-fold and fluid trapping was minimal in lungs pretreated with nifedipine before exsanguination. Results suggest a close association between bronchoconstriction and fluid trapping in guinea pig lungs.

Effects of surface tension and viscosity on airway reopening

1990 ◽  
Vol 69 (1) ◽  
pp. 74-85 ◽  
Author(s):  
D. P. Gaver ◽  
R. W. Samsel ◽  
J. Solway
Keyword(s):  
Surface Tension ◽  
Fluid Viscosity ◽  
Opening Pressure ◽  
Viscous Forces ◽  
Considerable Portion ◽  
Airway Opening ◽  
Wall Compliance ◽  
Large Opening ◽  
Surface Tension Forces ◽  
The Relationship

We studied airway opening in a benchtop model intended to mimic bronchial walls held in apposition by airway lining fluid. We measured the relationship between the airway opening velocity (U) and the applied airway opening pressure in thin-walled polyethylene tubes of different radii (R) using lining fluids of different surface tensions (gamma) and viscosities (mu). Axial wall tension (T) was applied to modify the apparent wall compliance characteristics, and the lining film thickness (H) was varied. Increasing mu or gamma or decreasing R or T led to an increase in the airway opening pressures. The effect of H depended on T: when T was small, opening pressures increased slightly as H was decreased; when T was large, opening pressure was independent of H. Using dimensional analysis, we found that the relative importance of viscous and surface tension forces depends on the capillary number (Ca = microU/gamma). When Ca is small, the opening pressure is approximately 8 gamma/R and acts as an apparent “yield pressure” that must be exceeded before airway opening can begin. When Ca is large (Ca greater than 0.5), viscous forces add appreciably to the overall opening pressures. Based on these results, predictions of airway opening times suggest that airway closure can persist through a considerable portion of inspiration when lining fluid viscosity or surface tension are elevated.

Tachykinin recovery during postmortem bronchoconstriction in guinea pig lungs

1991 ◽  
Vol 70 (3) ◽  
pp. 1215-1219 ◽  
Author(s):  
M. A. Martins ◽  
S. A. Shore ◽  
J. M. Drazen
Keyword(s):  
Substance P ◽  
Guinea Pig ◽  
Neutral Endopeptidase ◽  
Neurokinin A ◽  
Opening Pressure ◽  
Airway Opening ◽  
Isolated Lungs ◽  
Peak Value

We examined the role of substance P (SP) and neurokinin A (NKA) in the postmortem bronchoconstriction in guinea pig lungs using isolated lungs superfused via the trachea. Airway opening pressure (Pao) during superfusion was monitored and the superfusate collected for analysis of SP- and NKA-like immunoreactivities (SP-LI and NKA-LI, respectively). Peak Pao (39.0 +/- 3.9 cmH2O) was reached 10 min after starting superfusion; Pao decreased slowly thereafter, reaching only 9.9 +/- 2.2% of the peak value 2 h after starting superfusion (P less than 0.005); 12.6 +/- 2.6 and 34.0 +/- 9.7 fmol of SP-LI and NKA-LI, respectively, were found in the fraction corresponding to 10-20 min of superfusion. Recovered immunoreactivities decreased to 5.2 +/- 0.3 and 9.3 +/- 1.8 fmol of SP-LI and NKA-LI, respectively, in the fraction corresponding to 110-120 min of superfusion (P less than 0.05). Inhibition of neutral endopeptidase with thiorphan resulted in significantly greater increases in Pao (P less than 0.005) and augmentation of the recovery of SP-LI and NKA-LI (P less than 0.05 and P less than 0.001, respectively). Capsaicin treatment of animals 7-10 days before the removal of their lungs abolished the increase in Pao during superfusion and resulted in a significant decrease in the amount of SP-LI and NKA-LI recovered. Our data confirm that tachykinin release occurs during postmortem bronchoconstriction in guinea pig lungs and, furthermore, that tachykinin degradation by NEP modulates the intensity of this response.

Measurement of pleural pressure at low and high frequencies in normal rabbits

1987 ◽  
Vol 63 (3) ◽  
pp. 1142-1146 ◽  
Author(s):  
D. A. Chartrand ◽  
T. H. Ye ◽  
J. M. Maarek ◽  
H. K. Chang
Keyword(s):  
Body Surface ◽  
Pressure Transducer ◽  
Esophageal Pressure ◽  
Pleural Pressure ◽  
Opening Pressure ◽  
High Frequencies ◽  
Occlusion Test ◽  
Airway Opening ◽  
Catheter Tip ◽  
The Relationship

In eight tracheotomized adult rabbits placed in the supine position, we employed a catheter-tip piezoresistive pressure transducer to measure esophageal pressure (Pes) and assessed the validity of taking the changes in Pes to be the changes in pleural pressure (Ppl). We applied an occlusion test in which the tracheal cannula was occluded during either spontaneous inspiratory efforts or body surface oscillations ranging from 3 to 50 Hz. The relationship between Pes and airway opening pressure (Pao) was recorded. In all instances, the changes in Pes and Pao were virtually identical in both amplitude and phase. We conclude that, as evaluated by the occlusion test, a catheter-tip pressure transducer placed in the esophagus of rabbits can give adequate estimation of local pleural changes up to at least 50 Hz.

Release of tachykinins by histamine, methacholine, PAF, LTD4, and substance P from guinea pig lungs

1991 ◽  
Vol 261 (6) ◽  
pp. L449-L455 ◽  
Author(s):  
M. A. Martins ◽  
S. A. Shore ◽  
J. M. Drazen
Keyword(s):  
Substance P ◽  
Guinea Pig ◽  
Platelet Activating Factor ◽  
Neutral Endopeptidase ◽  
Neurokinin A ◽  
Opening Pressure ◽  
Leukotriene D4 ◽  
Airway Opening

The release of substance P- and neurokinin A-like immunoreactivities (SP-LI and NKA-LI) after tracheal infusion of histamine, methacholine, leukotriene D4, and platelet-activating factor was measured in isolated guinea pig lungs superfused through the trachea. Infusion of each of these agonists was associated with a significant (P less than 0.05) increase in the recovery of both SP-LI and NKA-LI from lung perfusates compared with preinfusion baseline recoveries of these peptides. After infusion of bronchoactive mediators, approximately 4-15 times more NKA-LI than SP-LI was recovered from the lung superfusate. Coincident with the release of neuropeptides, mediator infusion was accompanied by an increase in airway opening pressure (Pao). Addition to the perfusate of the neutral endopeptidase inhibitor thiorphan, 1 microM increased the change in Pao induced by histamine (10(-8) mol, P less than 0.005) and methacholine (10(-8) mol, P less than 0.02) and increased the recovery of NKA-LI (P less than 0.05 for histamine and methacholine). Addition of isoproterenol to the perfusion buffer reduced, but did not abolish, either the Pao response or the increased recovery of NKA-LI (P less than 0.05) observed after histamine infusion. We conclude that bronchoactive agonists have the capacity to release both SP-LI and NKA-LI, and we speculate that NKA contributes to the bronchomotor response observed in response to histamine or methacholine.

Mean airway opening pressure as an index of inspiratory muscle task intensity

1986 ◽  
Vol 60 (1) ◽  
pp. 304-306 ◽  
Author(s):  
F. D. McCool ◽  
D. E. Leith
Keyword(s):  
Endotracheal Tube ◽  
Inspiratory Muscle ◽  
Muscle Training ◽  
Opening Pressure ◽  
Mean Values ◽  
Time Integral ◽  
Pressure Time ◽  
Airway Opening ◽  
Inspiratory Resistance ◽  
The Relationship

The relationship between mean values of pressure (pressure-time integral including both inspiration and expiration) measured at the airway opening (Pao) and in the esophagus (Pes) is described for ventilation on a variety of external inspiratory resistances. Pao/Pes was 0.85 or greater when the external inspiratory resistance was a 4.0-mm or smaller endotracheal tube adaptor. Additionally, Pao can be easily and accurately measured by a slowly responding mechanical manometer. This device is simple in design, unpowered, inexpensive, and can be used outside the laboratory as part of an inspiratory muscle training program.

Northeast India as an Indigenous Centre for the Domestication of Plants and Animals

2017 ◽  
Author(s):  
Manjil Hazarika
Keyword(s):  
South Asian ◽  
Close Association ◽  
Northeast India ◽  
Indian Culture ◽  
Rice Agriculture ◽  
Animal Domestication ◽  
History Of ◽  
The Relationship ◽  
Diverse Cultures

Northeast India is situated at the nexus of the South Asian, Southeast Asian, and East Asian biogeographical realms and harbours diverse biota, providing a unique opportunity to archaeologists and anthropologists for the study of the relationship between humans and their environment over the ages. Moreover, this region, the abode of diverse ethnic groups with diverse cultures and customs, hints at a long history of continuous and close association between humans and nature, which is important in the understanding of plant and animal domestication. Genetic analysis of present-day domesticates with their wild counterparts provides valuable insights into their differentiation, time of domestication, and changes in their morphological traits through control by humans. The chapter also elucidates the role played by rice in Northeast Indian culture and highlights the long-term history of rice agriculture in the region.

scholarly journals Ferroptosis contributes to isoflurane-induced neurotoxicity and learning and memory impairment

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Pengfei Liu ◽  
Jing Yuan ◽  
Yetong Feng ◽  
Xin Chen ◽  
Guangsuo Wang ◽  
...  
Keyword(s):  
Cell Death ◽  
Learning And Memory ◽  
Memory Impairment ◽  
Close Association ◽  
Dimethyl Fumarate ◽  
Dependent Manner ◽  
Transport Chain ◽  
The Relationship

AbstractFerroptosis is a novel type of programmed cell death, which is different from apoptosis and autophagic cell death. Recently, ferroptosis has been indicated to contribute to the in vitro neurotoxicity induced by isoflurane, which is one of the most common anesthetics in clinic. However, the in vivo position of ferroptosis in isoflurane-induced neurotoxicity as well as learning and memory impairment remains unclear. In this study, we mainly explored the relationship between ferroptosis and isoflurane-induced learning and memory, as well as the therapeutic methods in mouse model. Our results indicated that isoflurane induced the ferroptosis in a dose-dependent and time-dependent manner in hippocampus, the organ related with learning and memory ability. In addition, the activity of cytochrome c oxidase/Complex IV in mitochondrial electron transport chain (ETC) was increased by isoflurane, which might further contributed to cysteine deprivation-induced ferroptosis caused by isoflurane exposure. More importantly, isoflurane-induced ferroptosis could be rescued by both ferroptosis inhibitor (ferrostatin-1) and mitochondria activator (dimethyl fumarate), which also showed effective therapeutic action against isoflurane-induced learning and memory impairment. Taken together, our data indicate the close association among ferroptosis, mitochondria and isoflurane, and provide a novel insight into the therapy mode against isoflurane-induced learning and memory impairment.

Calcium channels and excitation–contraction coupling in cardiac cells. I. Two components of contraction in guinea-pig papillary muscle

1987 ◽  
Vol 65 (9) ◽  
pp. 1821-1831 ◽  
Author(s):  
E. Honoré ◽  
M. M. Adamantidis ◽  
B. A. Dupuis ◽  
C. E. Challice ◽  
P. Guilbault
Keyword(s):  
Membrane Potential ◽  
Guinea Pig ◽  
Papillary Muscle ◽  
Cardiac Cells ◽  
Resting Membrane Potential ◽  
Tonic Component ◽  
Contraction Coupling ◽  
Rich Solution ◽  
The Relationship ◽  
Guinea Pig Atria

Biphasic contractions have been obtained in guinea-pig papillary muscle by inducing partial depolarization in K+-rich solution (17 mM) containing 0.3 μM isoproterenol; whereas in guinea-pig atria, the same conditions led to monophasic contractions corresponding to the first component of contraction in papillary muscle. The relationships between the amplitude of the two components of the biphasic contraction and the resting membrane potential were sigmoidal curves. The first component of contraction was inactivated for membrane potentials less positive than those for the second component. In Na+-low solution (25 mM), biphasic contraction became monophasic subsequent to the loss of the second component, but tetraethylammonium unmasked the second component of contraction. The relationship between the amplitude of the first component of contraction and the logarithm of extracellular Ca2+ concentration was complex, whereas for the second component it was linear. When Ca2+ ions were replaced by Sr2+ ions, only the second component of contraction was observed. It is suggested that the first component of contraction may be triggered by a Ca2+ release from sarcoplasmic reticulum, induced by the fast inward Ca2+ current and (or) by the depolarization. The second component of contraction may be due to a direct activation of contractile proteins by Ca2+ entering the cell along with the slow inward Ca2+ current and diffusing through the sarcoplasm. These results do not exclude the existence of a third "tonic" component, which could possibly be mixed with the second component of contraction.

scholarly journals EXTIRPATION OF THE THYMUS IN THE GUINEA PIG

1917 ◽  
Vol 25 (1) ◽  
pp. 129-152 ◽  
Author(s):  
Edwards A. Park
Keyword(s):  
Guinea Pig ◽  
Serial Section ◽  
Guinea Pigs ◽  
Close Association ◽  
Main Lobe ◽  
Technical Error ◽  
Serial Sections ◽  
Pharyngeal Pouch ◽  
The Third ◽  
Third Pharyngeal Pouch

1. Accessory lobes of thymus, derived from the third pharyngeal pouch, occurring in close association with the parathyroids from the third pouch, were found in serial section of the cervical tissues of eleven out of fourteen guinea pigs, and probably would have been found in all fourteen but for a technical error. 2. It is probable, therefore, that accessory lobes of thymus having this situation and origin are usually, if not always, present in the guinea pig. 3. Additional accessory lobes of thymus belonging to, but at some distance from the main lobe were also present in several of the animals. 4. The discovery of these accessory lobes makes it certain that the guinea pig is unsuitable material for complete thymectomy, and probably complete extirpation of the thymus in this animal is rarely, if ever accomplished. 5. The extirpation experiments of previous investigators in the guinea pig must now be regarded as partial extirpations, and their results interpreted in that light. 6. Extirpation of the thymus in the guinea pig produced no changes in the writer's experiments. 7. The study of the serial sections of the cervical tissues of the guinea pig indicates that Ruben's statements regarding the parathyroid derived from the fourth pharyngeal pouch in the guinea pig are correct,—that it is much smaller than parathyroid III, may be rudimentary, and is sometimes absent at least on one side. 8. No accessory lobe of thymus was found accompanying the parathyroid from the fourth pouch, a finding also bearing out Ruben's statement that no thymus anlarge springs from the fourth pouch in the guinea pig.

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