scholarly journals The Mechanism of Gill Ventilation in Three Freshwater Teleosts

1958 ◽  
Vol 35 (4) ◽  
pp. 807-823 ◽  
Author(s):  
G. M. HUGHES
Keyword(s):  
Negative Pressure ◽  
Time Course ◽  
Phase 1 ◽  
Quantitative Relationship ◽  
Differential Pressure ◽  
Positive Pressure ◽  
Pressure Curve ◽  
Suction Pump ◽  
Opening And Closing ◽  
Pressure Changes

1. A study has been made of the respiratory movements of three species of freshwater fish. The time course of pressure changes in the buccal and opercular cavities was recorded and movements of the mouth and operculum plotted from ciné films taken simultaneously. 2. Opening and closing of the mouth precede respectively abduction and adduction of the operculum by about one-fifth of a cycle. 3. The most prominent part of the buccal pressure curve is a positive pressure associated with mouth closing. The size of a negative pressure as the mouth opens is small in the trout but may be relatively large in the tench. 4. Abduction of the operculum produces a marked negative pressure in the opercular cavity of all three species and there is a slight positive pressure during its adduction. 5. The respiratory system is divided into a buccal and two opercular cavities and the concept of gill resistances separating them is introduced. 6. The respiratory cycle is made up of four phases which succeed one another. These are: phase (1) opercular suction pump predominant; phase (2) transition with a reduction in differential pressure between the buccal and opercular cavities; phase (3) buccal pressure pump predominant; and phase (4) transition with reversal of differential pressure. 7. With the exception of phase (4), which occupies only about one-tenth of a cycle, the pressure in the buccal cavity exceeds that in the opercular cavity throughout the cycle. It is therefore concluded that water will flow across the gills for almost the entire cycle but may reverse for this brief period. The quantitative relationship between the pressures and the volume of water flowing across the gills during different parts of the cycle will depend upon the properties of the gill resistances.

scholarly journals A Comparative Study of Gill Ventilation in Marine Teleosts

1960 ◽  
Vol 37 (1) ◽  
pp. 28-45 ◽  
Author(s):  
G. M. HUGHES
Keyword(s):  
Time Course ◽  
Clupea Harengus ◽  
Pressure Curve ◽  
Suction Pump ◽  
Lower Jaw ◽  
Sea Bottom ◽  
Gill Ventilation ◽  
Pressure Changes ◽  
Conger Conger

1. Movements of the lower jaw and operculum have been recorded simultaneously with the associated pressure changes in the buccal and opercular cavities during breathing of the following species: Trachurus trachurus (L.), Clupea harengus L., Gadus merlangus L., Onos mustela (L.), Crenilabrus melops (L.), Cottus bubalis Euphrasén, Blennius ocellaris L., Trigla gurnardus L., Callionymus lyra L., Pleuronectes platessa L., Microstoinus kitt (Walbaum), Conger conger (L.), Syngnathus acus L. 2. In all species ventilation of the gills is achieved by the action of a buccal pressure pump and of opercular suction pumps. 3. The time course of the pressure changes indicates differences in the relative importance of the two pumps which are related to the habitat of the fish. The suction pump becomes of greatest importance in fishes which spend most of their lives on the sea bottom. 4. In several species the differential pressure curve does not include the brief period of reversal in pressure gradient found in most fishes so far investigated. Notable among these species are the two flatfishes investigated and in which there is some evidence for an active opercular valve. 5. In general, the results confirm the validity of Baglioni's classification of the respiratory mechanisms of teleost fishes.

Study of Toynbee Phenomenon by Combined Intranasopharyngeal and Tympanometric Measurements

1988 ◽  
Vol 97 (2) ◽  
pp. 199-206 ◽  
Author(s):  
Yehuda Finkelstein ◽  
Yuval Zohar ◽  
Yoav P. Talmi ◽  
Nelu Laurian
Keyword(s):  
Middle Ear ◽  
Negative Pressure ◽  
Pressure Change ◽  
Positive Pressure ◽  
New Information ◽  
Pressure Changes ◽  
Rapid Pressure

The Toynbee maneuver, swallowing when the nose is obstructed, leads in most cases to pressure changes in one or both middle ears, resulting in a sensation of fullness. Since first described, many varying and contradictory comments have been reported in the literature concerning the type and amount of pressure changes both in the nasopharynx and in the middle ear. In our study, the pressure changes were determined by catheters placed into the nasopharynx and repeated tympanometric measurements. New information concerning the rapid pressure variations in the nasopharynx and middle ear during deglutition with an obstructed nose was obtained. Typical individual nasopharyngeal pressure change patterns were recorded, ranging from a maximal positive pressure of + 450 to a negative pressure as low as −320 mm H2O.

The Mechanism of Gill Ventilation in the Dogfish and Skate

1960 ◽  
Vol 37 (1) ◽  
pp. 11-27 ◽  
Author(s):  
G. M. HUGHES
Keyword(s):  
Time Course ◽  
Gill Slit ◽  
Suction Pump ◽  
Pressure Pump ◽  
The Individual ◽  
Triakis Semifasciata ◽  
Leopard Sharks ◽  
Pressure Changes ◽  
Respiratory Movements ◽  
Branchial Region

1. The respiratory movements of the dogfish, Scyliorhinus (Scyllium) canicula (L.), and the ‘skate’, Raia clavata L. (thornback ray), have been studied by the use of cinematographic and mechanotransducer recording methods. Simultaneous determinations of the time-course of pressure changes in the oro-branchial and parabranchial cavities were also made by means of Hansen condenser manometers. 2. In both species movements of the mouth precede those of the spiracular valve and of the branchial region. Adduction and abduction of the branchial region spreads serially from the first to last gill slit in the dogfish, but movements of the individual gill arches are more nearly synchronous in the skate. Opening of the flap valves formed by extensions of the inter-branchial septa are synchronous in both species. 3. Water entering one side of the mouth leaves by the three posterior gill slits of the same side. Water entering the spiracle leaves through the anterior slits of the same side. This separation of flow is less marked in the skate. 4. The pressure curves recorded in all parts of the system have both positive and negative phases with respect to the external medium. The positive phase, associated with closing of the mouth and spiracle, is larger in the oro-branchial than in the parabranchial cavities and vice versa. The time-course of the pressure changes indicates that the flow across the gills is maintained by the action of a pressure pump in front and a suction pump behind. 5. The suction pump plays a more important role than the pressure pump in the skate and its contribution to the flow across the gills is by no means negligible in the dogfish. 6. The differential pressure curves suggest that the flow across the gills is continuous except in the dogfish for a brief period when the gradient is reversed. The absence of this reversal in the skate suggests that the external gill slit openings are controlled by an active mechanism. This is probably an adaptation to bottom-living habit. 7. All these observations relate to animals which are stationary with respect to the water. During swimming at a reasonable speed leopard sharks (Triakis semifasciata) have been observed to make few or no respiratory movements, although they immediately ventilate actively on coming to rest at the bottom of the aquarium.

scholarly journals A Two-Mode Digital Pressure Meter Equipped With An Automatic Leak Test Using MPX5050gp And MPXv4115vc6u Sensors

2020 ◽  
Vol 2 (2) ◽  
pp. 80-85
Author(s):  
Fita Florensa Rooswita ◽  
Triana Rahmawati ◽  
Syaifudin Syaifudin
Keyword(s):  
Negative Pressure ◽  
Digital Data ◽  
Average Error ◽  
Positive Pressure ◽  
Leak Test ◽  
Suction Pump ◽  
Digital Pressure ◽  
Measurement Results ◽  
Pressure Meter ◽  
Selection Of

The calibration process aims to guarantee measurement results following established standards. The purpose of this study is to design an automatic leak test for digital pressure meter in which the function of this device is to measure pressure on the Sphygmomanometer and Suction Pump or other devices that use pressure parameters for measurement. This module uses the Arduino system as control and processing of analog data into digital data to condition the output of the MPX5050GP sensor for positive pressure and MPXV4115VC6U sensor for vacuum pressure, this module uses a 4x20 LCD character display and there is a selection of mmHg and Kpa units with fluctuating resolution 0.25. Also, in this module there is an automatic leak test feature for the Sphygmomanometer, the measurement results obtained an average error of 7.3 mmHg for sphygmomanometer measurements, and for suction pumps less than 1.5 Kpa. From these results, it was concluded that this module can be used for the measurement of devices that use positive pressure and negative pressure

Effect of negative-pressure breathing on lung mechanics and venous admixture

1964 ◽  
Vol 19 (4) ◽  
pp. 665-671 ◽  
Author(s):  
Tulio Velasquez ◽  
Leon E. Farhi
Keyword(s):  
Negative Pressure ◽  
Lung Compliance ◽  
Lung Mechanics ◽  
Positive Pressure ◽  
Venous Admixture ◽  
Respiratory Compliance ◽  
Anesthetized Dogs ◽  
Flow Through ◽  
Negative Pressure Breathing ◽  
Opening And Closing

Anesthetized dogs in the supine position show a spontaneous decrease in total respiratory compliance and an increase in venous admixture to the pulmonary circulation. Both these changes can be increased by negative-pressure breathing and reversed by positive-pressure breathing. If the changes in total respiratory compliance are due only to changes in lung compliance and these in turn result directly from the closure of alveoli, the relationship between compliance and inspiratory and expiratory pressure allows one to determine the scatter of opening and closing pressures in the alveoli. The venous admixture measures blood flow through collapsed alveoli, and its relationship to the negative pressure applied indicates the perfusion of the alveoli collapsing with each increment in negative pressure. By studying simultaneously changes in compliance and venous admixture, and using two basic assumptions, the dog's lungs can be described as a system composed of some elements receiving nearly 50% of the ventilation and 20% of the perfusion, relatively unstable mechanically, and having a very high Va/ Q ratio, while the remaining air spaces receive the same ventilation, but 80% of the perfusion. lung compliance; atelectasis; ventilation-perfusion ratio Submitted on October 28, 1963

scholarly journals Pressure Changes During Layer Cupping in a Skin Model

2021 ◽  
Vol 38 (2) ◽  
pp. 159-164
Author(s):  
Dong Wook Shim ◽  
Soo Kwang An ◽  
Ha Lim Lee ◽  
Jae Yong Lee ◽  
Byung Ryul Lee ◽  
...  
Keyword(s):  
3D Printing ◽  
Bacterial Infection ◽  
Negative Pressure ◽  
Pressure Change ◽  
Skin Model ◽  
Korean Medicine ◽  
Suction Pump ◽  
Pressure Changes

Background: Cupping is widely used in Korean medicine, but there is a risk of bacterial infection if the suction pump (used for inducing negative pressure) and the patients’ skin are not separated. This study aimed to investigate the effect of layer cupping by comparing the pressure changes between layer cupping and conventional cupping.Methods: To evaluate pressure changes the study was designed with 3 types of conditions applied to a skin model: (1) a Dongbang cup with a manual or motor suction pump (conventional cupping); (2) layer cupping with 2 Dongbang cups; and (3) layer cupping with a cup made by 3D printing and a Dongbang cup.Results: When a manual suction pump was used (conventional cupping), the pressure did not decrease steadily, and in 1 section there was an increase in pressure. When layer cupping was used, the pressure in the lower cup (which would be directly applied to the patient’s skin), decreased steadily.Conclusion: In the pressure change graph for layer cupping in this skin model, the pressure in the lower cup (which would be placed on the patient’s skin) steadily decreased, and reached equilibrium. Therefore, the layer cupping model may help to reduce the risks of bacterial infection.

The Variable-Pressure Neck-Chamber Method for Studying the Carotid Baroreflex in Man

1977 ◽  
Vol 53 (2) ◽  
pp. 165-171 ◽  
Author(s):  
J. Ludbrook ◽  
G. Mancia ◽  
A. Ferrari ◽  
A. Zanchetti
Keyword(s):  
Negative Pressure ◽  
Carotid Sinus ◽  
Venous Blood ◽  
Baroreceptor Reflex ◽  
Variable Pressure ◽  
Positive Pressure ◽  
Chamber Method ◽  
Carotid Baroreceptor ◽  
Pressure Changes ◽  
Neck Chamber

1. The variable-pressure neck-chamber method was analysed in ten healthy volunteer subjects to determine its suitability for the study of the carotid baroreceptor reflex in man. 2. Positive and negative pressures applied to the neck (range ± 60 mmHg) were always transmitted linearly to a tissue catheter outside the carotid sinus, but only 86% of positive pressure, and 64% of negative pressure. Tissue pressures were confirmed by simultaneous measurement in the internal jugular vein adjacent to the carotid sinus. 3. Positive and negative pressure changes within the above range did not alter Po2 of internal jugular venous blood, suggesting that cerebral blood flow was unaltered. 4. Positive pressure changes induced reflex pressor responses of similar magnitude at arterial Po2 12·8 and 70·1 kPa (96 and 527 mmHg), suggesting that the carotid chemoreceptors were not involved. 5. It is concluded that the variable-pressure neck chamber is a valid method for selectively studying the carotid baroreceptor reflex in man. However, transmission of external pneumatic pressure to the carotid sinus is imperfect and greater for positive than for negative pressure. This must be recognized to avoid underestimation of gain and distortion of shape of the reflex.

QUANTITATIVE DETERMINATION OF ENDOGENOUS PGI2 RELEASE IN ANAESTHETIZED BEAGLE DOGS

1987 ◽  
Author(s):  
F Hermán ◽  
P Hadházy ◽  
K Magyar
Keyword(s):  
Time Course ◽  
Pressure Curve ◽  
Beagle Dogs ◽  
Filtration Pressure ◽  
Thromboxane Receptor ◽  
Arterial Blood ◽  
Constant Rate ◽  
Endogenous Release ◽  
Thromboxane Receptor Antagonist ◽  
Pressure Changes

A 30μm diameter pore size screen was inserted into an arteriovenous bypass system in anaesthetized, heparin-treated beagle dogs. The arterial blood was directed through the screen by a roller pump at a constant rate. As a result, the pressure proximal to the filter continuously increased (F.Hermdn et al.Thromb. Res.44 /1986/,575). The concentration of proximally infused PGI2 that stabilized the filtration pressure curve (pressure stabilizing concentration= PSC) was determined. If it was low enough (between 0.4 and 1.5 nmol/1) we administered the PGI2-releaser bradykinin (1/ug/kg), angiotensin II (0.5/ug/kg) or ADP (20/ug/kg) in bolus dose intravenously. Together with the cnanges in blood pressure, we observed a transient decrease in filtration pressure. From the pressure changes, based on the previously determined PGI2 concentration-res-ponse relationship, we estimated the amounts of released PGI2 as well as the time course of this release. Indomethacin (2 mg/kg i.v.) significantly decreased the PSC for exogenous PGI2 thereby increasing the sensitivity of the method; the release of PGI2 was abolished. The sensitivity of the method could also be increased by infusing BM.13.177 - an endoperoxide, thromboxane receptor antagonist - proximal to the filter (final concentration: 1-10/ug/ml). This substance did not affect the release of PGI2.We conclude that by using this technique the endogenous release of prostacyclin can be continuously determined provided that PGI2 level exceeds 50 pg/ml.

scholarly journals Two Mode DPM Equipped with an Automatic Leak Test Using MPX5050GP and MPXV4115VC6U Sensors

2021 ◽  
Vol 3 (1) ◽  
pp. 1-7
Author(s):  
Fita Florensa Rooswita ◽  
Triana Rahmawati ◽  
Syaifudin Syaifudin
Keyword(s):  
Negative Pressure ◽  
Digital Data ◽  
Average Error ◽  
Positive Pressure ◽  
Leak Test ◽  
Suction Pump ◽  
Calibration Process ◽  
Pressure Calibration ◽  
Measurement Results ◽  
Selection Of

The calibration process aims to guarantee measurement results in accordance with established standards. One of the tools used for pressure calibration is the Digital Presure Meter, which is the function of this tool to measure pressure on the Sphygmomanometer and Suction Pump or other tools that use pressure parameters for measurement. This module uses the Arduino system as a control and processing of analog data into digital data in order to condition the output of the MPX5050GP sensor for positive pressure and MPXV4115VC6U sensor for vacum pressure, this module uses a 4x20 LCD character display and there is a selection of mmHg and Kpa units with fluctuating resolution 0.25. Also in this module there is also an automatic leak test feature for the Sphygmomanometer, the measurement results obtained an average error of 7.3 mmHg for sphymomanometer measurements, and for suction pumps less than 1.5 Kpa. From these results it was concluded that this module can be used for the measurement of tools that use positive pressure and negative pressure.

scholarly journals Effect of mesenchymal stromal cell infusions on lung function in COPD patients with high CRP levels

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Daniel J. Weiss ◽  
Karen Segal ◽  
Richard Casaburi ◽  
Jack Hayes ◽  
Donald Tashkin
Keyword(s):  
Lung Function ◽  
Time Course ◽  
Inflammatory Marker ◽  
Controlled Trial ◽  
Phase 1 ◽  
Forced Expiratory Volume ◽  
Allogeneic Mscs ◽  
Copd Exacerbations ◽  
Copd Patients ◽  
Patient Reported

Abstract Background We previously reported a Phase 1/2 randomized placebo-controlled trial of systemic administration of bone marrow-derived allogeneic MSCs (remestemcel-L) in COPD. While safety profile was good, no functional efficacy was observed. However, in view of growing recognition of effects of inflammatory environments on MSC actions we conducted a post-hoc analysis with stratification by baseline levels of a circulating inflammatory marker, C-reactive protein (CRP) to determine the effects of MSC administration in COPD patients with varying circulating CRP levels. Methods Time course of lung function, exercise performance, patient reported responses, and exacerbation frequency following four monthly infusions of remestemcel-L vs. placebo were re-assessed in subgroups based on baseline circulating CRP levels. Results In COPD patients with baseline CRP ≥ 4 mg/L, compared to COPD patients receiving placebo (N = 17), those treated with remestemcel-L (N = 12), demonstrated significant improvements from baseline in forced expiratory volume in one second, forced vital capacity, and six minute walk distance at 120 days with treatment differences evident as early as 10 days after the first infusion. Significant although smaller benefits were also detected in those with CRP levels ≥ 2 or ≥ 3 mg/L. These improvements persisted variably over the 2-year observational period. No significant benefits were observed in patient reported responses or number of COPD exacerbations between treatment groups. Conclusion In an inflammatory environment, defined by elevated circulating CRP, remestemcel-L administration yielded at least transient meaningful pulmonary and functional improvements. These findings warrant further investigation of potential MSC-based therapies in COPD and other inflammatory pulmonary diseases. Trial registration: Clinicaltrials.gov NCT00683722.

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