scholarly journals Insect-damagedArabidopsismoves like woundedMimosa pudica

2019 ◽  
Vol 116 (51) ◽  
pp. 26066-26071 ◽  
Author(s):  
Andrzej Kurenda ◽  
Chi Tam Nguyen ◽  
Aurore Chételat ◽  
Stéphanie Stolz ◽  
Edward E. Farmer
Keyword(s):  
Positive Pressure ◽  
Insect Damage ◽  
Water Fluxes ◽  
Insect Feeding ◽  
Electrical Signals ◽  
Feeding Sites ◽  
Leaf Movements ◽  
Movement And Deformation ◽  
Pressure Changes ◽  
Collapse Phase

Slow wave potentials (SWPs) are damage-induced electrical signals which, based on experiments in which organs are burned, have been linked to rapid increases in leaf or stem thickness. The possibility that pressure surges in injured xylem underlie these events has been evoked frequently. We sought evidence for insect feeding-induced positive pressure changes in the petioles ofArabidopsis thaliana. Instead, we found that petiole surfaces of leaves distal to insect-feeding sites subsided. We also found that insect damage induced longer-duration downward leaf movements in undamaged leaves. The transient petiole deformations were contemporary with and dependent on the SWP. We then investigated if mutants that affect the xylem, which has been implicated in SWP transmission, might modify SWP architecture.irregular xylemmutants strongly affected SWP velocity and kinetics and, in parallel, restructured insect damage-induced petiole deformations. Together, with force change measurements on the primary vein, the results suggest that extravascular water fluxes accompany the SWP. Moreover, petiole deformations inArabidopsismimic parts of the spectacular distal leaf collapse phase seen in woundedMimosa pudica. We genetically link electrical signals to organ movement and deformation and suggest an evolutionary origin of the large leaf movements seen in woundedMimosa.

Anatomical Effects of Sudden Middle Ear Pressure Changes

1979 ◽  
Vol 88 (3) ◽  
pp. 368-376 ◽  
Author(s):  
A. Axelsson ◽  
J. Miller ◽  
M. Silverman
Keyword(s):  
Tympanic Membrane ◽  
Middle Ear ◽  
Round Window ◽  
Applied Pressure ◽  
Positive Pressure ◽  
Air Bubbles ◽  
Scala Tympani ◽  
Middle Ear Pressure ◽  
Contralateral Ear ◽  
Pressure Changes

Acute middle ear (ME) and inner ear changes following brief unilateral phasic ME pressure changes (up to ± 6000/mm H2O) were studied in the guinea pig. Middle ear findings included perforation of the tympanic membrane, serous and serosanguinous exudate and hemorrhage of tympanic membrane and periosteal vessels. Changes were related to magnitude of applied pressure. Perforation and hemorrhage were more commonly seen with negative rather than positive pressure. Air bubbles behind the round window were seen with positive pressures. Occasional distortion, but never perforation of the round window, was noted. Hemorrhage of the scala tympani was observed with both positive and negative pressures; scala vestibuli hemorrhage was found with negative ME pressure. In some instances pressure direction and magnitude related changes were seen in the contralateral ear.

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.

Measurement above the carina of FiO2 and Positive Pressure changes using different HFNO rates.

2020 ◽  
Vol 30 ◽  
pp. e71-e72
Author(s):  
Jose Luis Soriano-Bru ◽  
Jaume Puig ◽  
Juan Catala Bauset
Keyword(s):  
Positive Pressure ◽  
Pressure Changes

The Distribution of P O2 and Hydrostatic Pressure Changes Within the Branchial Chambers in Relation to GILL VENTILATION OF THE SHORE CRAB CARCINUS MAENAS L

1969 ◽  
Vol 51 (1) ◽  
pp. 203-220
Author(s):  
G. M. HUGHES ◽  
B. KNIGHTS ◽  
C. A. SCAMMELL
Keyword(s):  
Hydrostatic Pressure ◽  
Ventilation System ◽  
Carcinus Maenas ◽  
Pressure Change ◽  
Shore Crab ◽  
Positive Pressure ◽  
Transparent Plastic ◽  
Gill Lamellae ◽  
Minimum Disturbance ◽  
Pressure Changes

1. A technique is described for replacing part of the branchiostegite of Carcinus maenas by a transparent plastic ‘window’ for direct observation of the gills in situ with minimum disturbance. 2. Observation of dye streams shows that most water enters the hypobranchial space through the Milne-Edwards openings above the chelae, flowing anteriorly and/or posteriorly to ventilate most of gills 3-8. Water also enters above the pereiopods to ventilate the rest of the gills. Water passes from the hypobranchial to the epibranchial space, confirming that there is a counterflow with respect to the circulation of blood through the gill lamellae. 3. By sampling water at different points in the branchial system, patterns of oxygen removal were studied. The gradients confirmed the direction of water flow observed by the use of dyes. 4. Rhythmic changes in hydrostatic pressure in normal forward-pumping of 3-12 mm. H2O were recorded from the branchial cavities, superimposed on a maintained negative pressure relative to that outside the crab of 0-10 mm. H2O. Reversals produced a brief positive pressure change of 0-22 mm. H2O. 5. The possible relationships of the rhythmic pressure changes to scaphognathite movements are discussed. 6. The role of reversals is discussed and it is concluded that their primary function during ventilation is in helping to clean the ventrally facing gill surfaces. But they are also important in respiration under certain special conditions which arise during the normal life of the animal. 7. The utilization of O2 during its passage over the gills is low (7-23%) in spite of the counterflow. Possible explanations of this are discussed in relation to a model of the whole ventilation system.

Ancient Bug Bites on Ancient Plants Record Forest Ecosystem Response to Environmental Perturbations

2013 ◽  
Vol 19 ◽  
pp. 157-174 ◽  
Author(s):  
Ellen D. Currano
Keyword(s):  
Trophic Interactions ◽  
Insect Herbivory ◽  
Fossil Flora ◽  
Local Perturbation ◽  
Insect Damage ◽  
Ecosystem Response ◽  
Insect Feeding ◽  
First Case ◽  
The Impact

Leaf-compression fossils with insect feeding traces are unique in providing rich, direct evidence of two levels in a fossil food web. Plant-insect associations dominate terrestrial trophic interactions, emphasizing the need to understand their ecological and evolutionary history. This paper first discusses methods of recognizing insect herbivore damage on fossil leaves and quantifying fossil insect herbivory. By conducting an unbiased insect damage census, damage frequency (percent of leaves with insect feeding damage), percent of leaf surface area removed by insects, and damage diversity (the number of discrete damage morphotypes, or DTs, found on a fossil flora or individual host plant) can all be measured. Three examples of responses of past plant-insect trophic interactions to environmental stresses are examined. In the first case study, late Oligocene fossil floras from Ethiopia document forest response to local perturbation and key characteristics to recognize disturbance in the plant fossil record. The second case study considers the terrestrial ecosystem response to the catastrophic global perturbation at the Cretaceous–Paleogene boundary. In the third case study, the impact of past global warming events—including the Paleocene–Eocene Thermal Maximum—on insect herbivory is discussed. Productive avenues for further research include: insect damage studies conducted outside the North American Cretaceous and Paleogene, actualistic and taphonomic studies of insect herbivory, and tighter collaboration across paleobotany, paleoentomology, botany, and entomology.

scholarly journals Increases in Cuff Volume and Pressure in Red Rubber Endotracheal Tubes during Anaesthesia

1979 ◽  
Vol 7 (2) ◽  
pp. 152-157 ◽  
Author(s):  
W. R. Thompson ◽  
T. E. Oh
Keyword(s):  
Nitrous Oxide ◽  
Cuff Pressure ◽  
Intermittent Positive Pressure Ventilation ◽  
Spontaneous Respiration ◽  
Oxygen Mixture ◽  
Positive Pressure ◽  
Cuff Volume ◽  
Endotracheal Tubes ◽  
Nitrous Oxide Oxygen ◽  
Pressure Changes

Increases in endotracheal tube cuff volume and pressure during anaesthesia have been reported to be due to the diffusion of nitrous oxide into the cuff. This study compared cuff volume and pressure changes in anaesthetized intubated patients who were ventilated with those allowed to breath spontaneously. The cuffs of Magill red rubber endotracheal tubes were inflated with either air or a nitrous oxide-oxygen mixture. Serial pressure and volume recordings confirmed that both parameters increased when the cuff was inflated with air. The increase in cuff pressure was however, greater during intermittent positive pressure ventilation than for spontaneous respiration. There were no significant changes when the cuff was inflated with the nitrous oxide-oxygen mixture.

scholarly journals Delayed Presentation of Traumatic Right-Sided Diaphragmatic Hernia after Abdominoplasty

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
Caroline C. Jadlowiec ◽  
Lois U. Sakorafas
Keyword(s):  
Diaphragmatic Hernia ◽  
Normal Pressure ◽  
Positive Pressure ◽  
Delayed Presentation ◽  
Pressure Gradients ◽  
Abrupt Changes ◽  
Thoracic And Abdominal ◽  
Pressure Changes ◽  
Surgical Manipulation ◽  
Diaphragmatic Hernias

Traumatic diaphragmatic hernias are rare and challenging to diagnose. Following trauma, diagnosis may occur immediately or in a delayed fashion. It is believed that left traumatic diaphragmatic hernias are more common as a result of the protective right-sided anatomic lie of the liver. If unrecognized, traumatic diaphragmatic injuries are subject to enlarge over time as a result of the normal pressure changes observed between the thoracic and abdominal cavities. Additionally, abrupt changes to the pressure gradients, such as those which occur with positive pressure ventilation or surgical manipulation of the abdominal wall, can act as a nidus for making an asymptomatic hernia symptomatic. We report our experience with a delayed traumatic right-sided diaphragmatic hernia presenting with large bowel incarceration two months after abdominoplasty. In our review of the literature, we were unable to find any reports of delayed presentation of a traumatic right-sided diaphragmatic hernia occurring acutely following abdominoplasty.

Effect of lung volume on the respiratory action of the canine pectoral muscles

1992 ◽  
Vol 73 (6) ◽  
pp. 2408-2412 ◽  
Author(s):  
S. R. Muza ◽  
G. J. Criner ◽  
S. G. Kelsen
Keyword(s):  
Electrical Stimulation ◽  
Lung Volume ◽  
Intrathoracic Pressure ◽  
Pectoral Muscle ◽  
Positive Pressure ◽  
Rib Cage ◽  
Mechanical Coupling ◽  
Negative Intrathoracic Pressure ◽  
Pressure Changes ◽  
Stimulation Of

Lung volume influences the mechanical action of the primary inspiratory and expiratory muscles by affecting their precontraction length, alignment with the rib cage, and mechanical coupling to agonistic and antagonistic muscles. We have previously shown that the canine pectoral muscles exert an expiratory action on the rib cage when the forelimbs are at the torso's side and an inspiratory action when the forelimbs are held elevated. To determine the effect of lung volume on intrathoracic pressure changes produced by the canine pectoral muscles, we performed isolated bilateral supramaximal electrical stimulation of the deep pectoral and superficial pectoralis (descending and transverse heads) muscles in 15 adult supine anesthetized dogs during hyperventilation-induced apnea. Lung volume was altered by application of a negative or positive pressure (+/- 30 cmH2O) to the airway. In all animals, selective electrical stimulation of the descending, transverse, and deep pectoral muscles with the forelimbs held elevated produced negative intrathoracic pressure changes (i.e., an inspiratory action). Moreover, with the forelimbs elevated, increasing lung volume decreased both pectoral muscle fiber precontraction length and the negative intrathoracic pressure changes generated by contraction of each of these muscles. Conversely, with the forelimbs along the torso, increasing lung volume lengthened pectoral muscle precontraction length and augmented the positive intrathoracic pressure changes produced by muscle contraction (i.e., an expiratory action). These results indicate that lung volume significantly affects the length of the canine pectoral muscles and their mechanical actions on the rib cage.

Modulation of bat wing venule contraction by transmural pressure changes

1992 ◽  
Vol 262 (3) ◽  
pp. H625-H634 ◽  
Author(s):  
M. J. Davis ◽  
X. Shi ◽  
P. J. Sikes
Keyword(s):  
Venous Pressure ◽  
Transmural Pressure ◽  
The Body ◽  
Intraluminal Pressure ◽  
Positive Pressure ◽  
Cross Sectional ◽  
Series Of Experiments ◽  
Pressure Changes ◽  
Bat Wing

We tested the hypothesis that the frequency and amplitude of spontaneous venular contractions in the bat wing could be modulated by changes in transmural pressure. In one series of experiments, venous pressure in the wing was elevated by pressurizing a box containing the body of the animal while the wing was exposed to atmospheric pressure. During this time, venular diameters were continuously recorded using intravital microscopic techniques while venular pressures were measured through servo-null micropipettes. In another series of experiments, single venular segments were dissected from the wing, cannulated, and pressurized in vitro. The results from both experimental protocols were qualitatively similar; alterations in venous pressure over a narrow range (+/- 5 cmH2O from control) produced substantial changes in contraction frequency and amplitude. The product of frequency and cross-sectional area was maximal over the venous pressure range between 10 and 15 cmH2O. Venules demonstrated a rate-sensitive component in their reaction to rapid pressure changes, because contraction bursts occurred immediately after positive pressure steps and quiescent periods often occurred after negative pressure steps. We conclude that venular vasomotion in the bat wing is modulated by intraluminal pressure and involves a bidirectional, rate-sensitive mechanism. In addition, comparisons with arteriolar vasomotion studies suggest that venules are more sensitive to luminal pressure changes than arterioles.

Effects of transmural pressure on brachial artery mean blood velocity dynamics in humans

2002 ◽  
Vol 93 (6) ◽  
pp. 2137-2146 ◽  
Author(s):  
Mary E. J. Lott ◽  
Michael D. Herr ◽  
Lawrence I. Sinoway
Keyword(s):  
Brachial Artery ◽  
Pressure Change ◽  
Blood Velocity ◽  
Voluntary Contraction ◽  
Transmural Pressure ◽  
Positive Pressure ◽  
Myogenic Response ◽  
Vascular Responses ◽  
Pressure Changes ◽  
Handgrip Contractions

The effects of changes in transmural pressure on brachial artery mean blood velocity (MBV) were examined in humans. Transmural pressure was altered by using a specially designed pressure tank that raised or lowered forearm pressure by 50 mmHg within 0.2 s. Brachial MBV was measured with Doppler directly above the site of forearm pressure change. Pressure changes were evoked during resting conditions and after a 5-s handgrip contraction at 25% maximal voluntary contraction. The handgrip protocol selected was sufficiently vigorous to limit flow and sufficiently brief to prevent autonomic engagement. Changes in transmural pressure evoked directionally similar changes in MBV within 2 s. This was followed by large and rapid adjustments [−2.14 ± 0.24 cm/s (vasoconstriction) during negative pressure and +2.14 ± 0.45 cm/s (vasodilatation) during positive pressure]. These adjustments served to return MBV to resting levels. This regulatory influence remained operative after 5-s static handgrip contractions. Of note, changes in transmural pressure were capable of altering the timing of the peak MBV response (5 ± 0, 2 ± 0, 6 ± 1 s ambient, negative, and positive pressure, respectively) as well as the speed of MBV adjustment (−2.03 ± 0.18, −2.48 ± 0.15, −0.84 ± 0.19 cm · s−1 · s−1ambient, negative, and positive pressure, respectively) after handgrip contractions. Vascular responses, seen with changes in transmural pressure, provide evidence that the myogenic response is normally operative in the limb circulation of humans.

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