Discriminating transudates and exudates in dogs with pleural effusion: diagnostic utility of simplified Light’s criteria compared with traditional veterinary classification

2020 ◽  
Vol 187 (1) ◽  
pp. e5-e5
Author(s):  
Andrea Zoia ◽  
Matteo Petini ◽  
Danila Righetti ◽  
Marco Caldin ◽  
Michele Drigo
Keyword(s):  
Hydrostatic Pressure ◽  
Pleural Effusion ◽  
Pressure Gradient ◽  
Total Protein ◽  
Diagnostic Value ◽  
Colloid Osmotic Pressure ◽  
Diagnostic Utility ◽  
Cross Sectional ◽  
True Nature ◽  
Hydrostatic Pressure Gradient

ObjectivesTo determine whether the simplified Light’s criteria (ie, pleural effusion lactate dehydrogenase concentration and serum total protein) can identify the pathophysiology of pleural effusion formation in dogs, and to assess whether these criteria were more accurate than the traditional veterinary classification based on pleural effusion total protein (TPp) and nucleated cell count (TNCCp).MethodsThis is a cross-sectional study including 100 dogs with pleural effusion. The aetiology of effusion was used to classify the pathophysiology of its formation. Parameters measured included the simplified Light’s criteria, TPp and TNCCp. The diagnostic utility of the two methods in classifying pleural effusion formation was evaluated.ResultsSeven transudates due to decreased colloid osmotic pressure, 18 transudates due to increased hydrostatic pressure gradient and 75 exudates were included in the study. The simplified Light’s criteria misclassified 2 of 75 exudates (98 per cent overall accuracy). The traditional veterinary classification scheme misclassified 31 of 75 exudates and 12 of 18 increased hydrostatic pressure gradient transudates (57 per cent overall accuracy). The frequency of agreement between the simplified Light’s criteria and the traditional veterinary classification with the true nature of the pleural effusion was significantly different (P<0.001).Clinical significanceThe simplified Light’s criteria were highly accurate in discriminating exudates from transudates, while TPp and TNCCp had no diagnostic value in doing so.

scholarly journals Electromyography of the Respiratory Muscles and Gill Water Flow in the Dragonet

1968 ◽  
Vol 49 (3) ◽  
pp. 583-602
Author(s):  
G. M. HUGHES ◽  
C. M. BALLINTIJN
Keyword(s):  
Hydrostatic Pressure ◽  
Stroke Volume ◽  
Pressure Gradient ◽  
Time Course ◽  
Respiratory Muscles ◽  
Adverse Pressure Gradient ◽  
Pressure Head ◽  
Volume Flow ◽  
Frequency Change ◽  
Hydrostatic Pressure Gradient

1. An account is given of the main skeletal elements and muscles involved in the respiratory movements of the dragonet, Callionymus lyra. 2. Using electromyographic techniques it has been shown that the muscles chiefly involved in rapid ejection of water out of the opercular slit are the adductor mandibulae, protractor hyoideus, and hyohyoideus. During the expansion phase of the cycle, which is about six times the duration of the contraction phase, the levator hyomandibulae and sternohyoideus are active, though in some cases the latter only comes in at higher levels of pumping. 3. Changes in volume flow across the gills have been produced by either (a) altering the hydrostatic pressure gradient (Δp) across the system, or (b) altering the oxygen or carbon dioxide content of the water inspired by the fish. With (a), the volume flow decreases linearly at a rate of about 30 ml./min./cm. H2O static pressure head until an inflexion is reached in the curve at which rate of flow decreases and is normally when Δp is zero. That the relative increase in flow rate with negative Δp's is due to the activity of the fish pumping against the adverse pressure gradient has been confirmed by electromyogram recordings during such experiments. With (b), it was possible to demonstrate a clear relationship between stroke volume and the level of electrical activity as measured by the height of the integrated electromyogram. The integrated EMG increases more than linearly with increasing stroke volume during PO2 changes, but this relationship seems to be more nearly linear during changes in CO2 concentration. 4. The respiratory frequency is scarcely affected by changes in flow produced by altering the hydrostatic pressure gradient, but following a decrease in PO2 or an increase in CO2 there is a significant fall in frequency which accompanies the increased electromyogram. The time course of these changes during recovery from a decrease in PO2 or an increase in PCOCO2 suggests that the gas tensions of the inspired water are detected by receptors on the gills and thus influence the electromyogram activity, but the frequency change observed is due to a change in the blood affecting receptors in the brain.

A cloned renal epithelial Na+ channel protein displays stretch activation in planar lipid bilayers

1995 ◽  
Vol 268 (6) ◽  
pp. C1450-C1459 ◽  
Author(s):  
M. S. Awayda ◽  
I. I. Ismailov ◽  
B. K. Berdiev ◽  
D. J. Benos
Keyword(s):  
Hydrostatic Pressure ◽  
Pressure Gradient ◽  
Lipid Bilayers ◽  
Single Channel ◽  
Na Channel ◽  
Planar Lipid Bilayers ◽  
Stretch Activation ◽  
Hydrostatic Pressure Gradient ◽  
Epithelial Na Channel

We have previously cloned a bovine renal epithelial channel homologue (alpha-bENaC) belonging to the epithelial Na+ channel (ENaC) family. With the use of a rabbit nuclease-treated in vitro translation system, mRNA coding for alpha-bENaC was translated and the polypeptide products were reconstituted into liposomes. On incorporation into planar lipid bilayers, in vitro-translated alpha-bENaC protein 1) displayed voltage-independent Na+ channel activity with a single-channel conductance of 40 pS, 2) was mechanosensitive in that the single-channel open probability was maximally activated with a hydrostatic pressure gradient of 0.26 mmHg across the bilayer, 3) was blocked by low concentrations of amiloride [apparent inhibitory constant of amiloride (K(i)amil approximately 150 nM], and 4) was cation selective with a Li+:Na+:K+ permselectivity of 2:1:0.14 under nonstretched conditions. These pharmacological and selectivity characteristics were altered to a lower amiloride affinity (K(i)amil > 25 microM) and a lack of monovalent cation selectivity in the presence of a hydrostatic pressure gradient. This observation of stretch activation (SA) of alpha-bENaC was confirmed in dual electrode recordings of heterologously expressed alpha-bENaC whole cell currents in Xenopus oocytes swelled by the injection of 15 nl of a 100 mM KCl solution. We conclude that alpha-bENaC, and by analogy other ENaCs, represent a novel family of cloned SA channels.

scholarly journals Role of a Hydrostatic Pressure Gradient in the Formation of Early Ischemic Brain Edema

1986 ◽  
Vol 6 (5) ◽  
pp. 546-552 ◽  
Author(s):  
Shizuo Hatashita ◽  
Julian T. Hoff
Keyword(s):  
Hydrostatic Pressure ◽  
Pressure Gradient ◽  
Water Content ◽  
Brain Edema ◽  
Intraluminal Pressure ◽  
Tissue Pressure ◽  
Ischemic Brain ◽  
Hydrostatic Pressure Gradient ◽  
Arterial Blood ◽  
Ischemic Brain Edema

We studied whether a hydrostatic pressure gradient between arterial blood and brain tissue plays a role in the formation of early ischemic cerebral edema after middle cerebral artery (MCA) occlusion in cats. Tissue pressure, regional CBF, and water content were measured from the cortex in the core and the peripheral zone of brain normally perfused by the MCA. Intraluminal arterial pressure was altered at intervals by inflation of an aortic balloon to vary the blood–tissue pressure gradient in the ischemic zone. Brain water content in the ischemic core, where flow fell to 5.5 ml/100 g/min, increased within 1 h of occlusion. After occlusion tissue pressure rose from 7.95 ± 0.72 mm Hg at 1 h to 13.16 ± 1.13 mm Hg at 3 h. When intraluminal pressure was increased, water content increased further, but only at 1 h after occlusion. In the periphery where flow was 18.9 ml/100 g/min during normotension. neither water content nor tissue pressure rose within 3 h of occlusion. Increased intraluminal pressure was accompanied by increased water content only at 3 h. This study indicates that a hydrostatic pressure gradient is an important element in the development of ischemic brain edema, exerting its major effect during the initial phase of the edema process.

scholarly journals Assessment of the diagnostic value of CEA, CA125, and CRP and their cut-off point for discrimination of exudative pleural effusions

Bionatura ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 1944-1947
Author(s):  
Hanie Raji ◽  
Seyed Hamid Borsi ◽  
Mehrdad Dargahi MalAmir ◽  
Ahmad Reza Asadollah Salmanpour
Keyword(s):  
Pleural Effusion ◽  
Tumor Marker ◽  
Pleural Fluid ◽  
Tumor Markers ◽  
Low Cost ◽  
High Specificity ◽  
Diagnostic Value ◽  
Pleural Effusions ◽  
Cross Sectional ◽  
The Mean

Pleural effusion is divided into exudative and transudative effusion, and the distinction between exudate and transudate requires multiple investigations of biochemical parameters and their comparison in pleural fluid and serum. This study aimed to assess the diagnostic value of CEA, CA125, and CRP and their cut-off point for discrimination of exudative pleural effusions. This epidemiological and cross-sectional study was performed on 50 patients aged between 18 to 90 years with the diagnosis of exudative pleural effusion referred to Imam Khomeini Hospital in Ahvaz in 2018 and 2019. Demographic and clinical information of patients were collected. The pleural effusion was diagnosed based on physical examination and chest radiography. Pleural effusion was confirmed by thoracentesis. A pleural fluid sample was taken from all patients, and the levels of CEA, CA125, and CRP markers were measured in the pleural fluid. Differentiation of transudate and exudate pleural effusions was performed using Light criteria. The mean CEA and CA125 level of pleural fluid were significantly higher, and the mean CRP level of pleural fluid was significantly lower in patients with malignant diagnoses (P <0.05). Cut-off value with highest sensitivity and specificity in differentiating types of exudative pleural effusions was obtained for CEA tumor marker (greater than 49.8), CA125 tumor marker (greater than 814.02), and CRP marker (less than 7.56). Also, in differentiating types of exudative pleural effusions, CEA tumor marker had sensitivity (89.03%) and specificity (78.42%); CA125 tumor marker had sensitivity (53.18%) and specificity (62.44%), and CRP marker had sensitivity (82.16%), and specificity (89.05%) were. Although the tumor markers had high specificity in the present study, the low sensitivity of some of these tumor markers reduced their diagnostic value. On the other hand, given the numerous advantages of tumor markers, such as low cost and non-invasive, combining them with another can increase the diagnostic value and accuracy.

Is Phloem Transport Due to a Hydrostatic Pressure Gradient? Supporting Evidence From Pressure Chamber Experiments

1987 ◽  
Vol 14 (4) ◽  
pp. 397 ◽  
Author(s):  
PEH Minchin ◽  
MR Thorpe
Keyword(s):  
Hydrostatic Pressure ◽  
Phaseolus Vulgaris ◽  
Pressure Gradient ◽  
Phloem Transport ◽  
Pressure Chamber ◽  
Supporting Evidence ◽  
Hydrostatic Pressure Gradient

A pressure chamber was used to increase suddenly the hydrostatic pressure in the upper shoot of a Phaseolus vulgaris plant while observing phloem transport of 11C-labelled photoassimilate. Phloem transport in the stem towards the chamber stopped immediately when pressure was applied and then recovered within about 5 min. If the pressure was then released, flow increased again. The results support the hypothesis that flow of photoassimilate in the stem phloem was driven by a hydrostatic pressure gradient.

Laterally accreting sinuous channels and their deposits: The Goldilocks of deep-water slope systems

2021 ◽  
Vol 91 (5) ◽  
pp. 451-463
Author(s):  
R.W.C. (Bill) Arnott ◽  
Mike Tilston ◽  
Patricia Fraino ◽  
Lillian Navarro ◽  
Gerry Dumouchel ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Pressure Gradient ◽  
Deep Sea ◽  
Size Fraction ◽  
Cross Flow ◽  
Fine Sand ◽  
Point Bar ◽  
Hydrostatic Pressure Gradient ◽  
Lateral Channel ◽  
High Resolution Images

ABSTRACT Channels with a sinuous planform are common in both continental and deep-marine environments on Earth, and similarly in high-resolution images of the surface of Mars. Whereas common in rivers, continuous lateral channel migration and point-bar deposition appear to be much less common in the deep sea. In the bends of rivers, near-bed flow driving point bar growth results from a cross-flow superelevation of the water surface that sets up a lateral hydrostatic pressure gradient driving an inward-directed flow near the bed. However, in deep-marine systems the surface between the turbidity current and overlying ambient fluid sits well above the channel margins, and therefore precludes a similar lateral superelevation of the current top. Here it is argued that the cross-flow component is related to a density gradient that mimics the effect of the hydrostatic pressure gradient in rivers, and develops as coarse suspended particles that experience little uplift, and therefore negligible overspill, become concentrated along the outer bank. This condition develops best in a two-part suspension made up of a highly concentrated, unstratified basal plug of coarse sediment overlain sharply by a dilute cloud of much finer sediment—a density structure that differs from the more typical upward exponential decrease in density. The abundance of coarse and fine sand, but depletion in the intermediate grain size fraction, is related to transgressive shelf processes and its influence on sediment supplied to the system, and in turn, the flow structure of the current. It is under these seemingly uncommon granulometric conditions that continuous laterally migrating channels, and accordingly, riverine-like point-bar deposition, is most common in the deep sea.

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