Determinants of pressure exerted by medical compression stockings

Phlebologie ◽  
2007 ◽  
Vol 36 (05) ◽  
pp. 237-244 ◽  
Author(s):  
B. Lun ◽  
J. F. Uhl ◽  
Y. Bringer ◽  
W. Blättler
Keyword(s):  
Muscle Activation ◽  
Compression Stocking ◽  
Relative Role ◽  
Pressure Amplitude ◽  
Interface Pressure ◽  
Compression Stockings ◽  
In Situ Techniques ◽  
The One

Summary Objective: The force exerted on a limb by a medical compression stocking (MCS) is given by the properties of the yarn and the technique of knitting. The pressure determined by the manufacturer should be the one acting on the leg provided the stocking fits the leg shape. However, the interface pressure is governed by additional factors which act simultaneously in a poorly defined manner. We sorted out the different material- and patient-related components and assessed their relative role combining in vitro with in situ techniques. Design and method: The force exerted by the stockings was measured with the Zwick and Hosy dynamometers and the pressure exerted on the leg with the SIGaT instrument placed underneath the stockings at various sites. Leg circumference was determined with the Perometer and local radius calculated from computer tomographic slices and assessed with templates. Stockings exerting ankle pressures between 10 and 40 mmHg were tested. Subjects serving in the various experiments were selected from a pool of 28 healthy volunteers. Results: All stockings exerted the predefined pressure when measured at the stocking/leg-interface (in situ) and on the dynamometer (in vitro) provided the local leg curvature was taken into account. The stockings showed slightly different elastic properties (pressure amplitude difference upon leg movement 2–6mmHg). The interface pressure varied significantly when measured at different angular positions on the same circumference (range of change +40%; –20%). The differences were strongly correlated with the local radius (range of variation along the calf circumference 35–125 mm). The differences of local radii got smaller with higher interface pressures. Leg movements provoked simultaneous increases and decreases of interface pressure of up to 15 mmHg depending on the site of measurement. Leg circumference varied only slightly with movements pointing in either direction: 0.25 cm at the ankle (range +0.4; –0.4) and 0.33 cm at the calf (range +1.05; –1.45), respectively. The compressibility of the underlying tissue had no effect on the interface pressure. Conclusions: The interface pressure can be assessed reliably in vitro and in situ. It shows complex, quantitatively important non-uniform local variations both when measured along a given leg circumference at rest and when monitored at one particular site during movements. The changes reflect the discontinuity of the leg configuration and further alterations of the silhouette occurring with every muscle activation. Clearly, a massage effect of stockings is documented which does not necessarily reflect a global effect exerted on the leg.

scholarly journals The Effect of Glutamate Receptor Agonists on Mouse Retinal Astrocyte [Ca2+]i

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Stephanie N. Blandford ◽  
William H. Baldridge
Keyword(s):  
Imaging Techniques ◽  
Ion Concentration ◽  
Retinal Astrocytes ◽  
Glutamate Agonists ◽  
Glutamate Receptor Agonists ◽  
Intracellular Calcium Ion ◽  
The One ◽  
Calcium Ion Concentration

Calcium-imaging techniques were used to determine if mouse retinal astrocytesin siturespond to agonists of ionotropic (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, AMPA; N-methyl-D-aspartate, NMDA) and metabotropic (S-3,5-dihydroxyphenylglycine, DHPG;trans-1-amino-1,3-cyclopentanedicarboxylic acid, ACPD) glutamate receptors. In most cases we found no evidence that retinal astrocyte intracellular calcium ion concentration (Ca2+i) increased in response to these glutamate agonists. The one exception was AMPA that increasedCa2+iin some, but not all, mouse retinal astrocytesin situ. However, AMPA did not increaseCa2+iin mouse retinal astrocytesin vitro, suggesting that the effect of AMPAin situmay be indirect.

In vitro and in situ nutrient degradability of barley and wheat milling byproducts

1998 ◽  
Vol 78 (3) ◽  
pp. 457-459 ◽  
Author(s):  
A. F. Mustafa ◽  
J. J. McKinnon ◽  
D. A. Christensen
Keyword(s):  
Key Words ◽  
Grain Weight ◽  
In Situ Techniques ◽  
Comparison Results ◽  
Key Words Barley

A study was conducted to estimate nutrient degradability of barley milling byproducts (BMBP) using in vitro and in situ techniques. Three levels of milling (5.9, 9.5 and 17%), representing the proportion of byproduct to the original grain weight were tested. A wheat byproduct (WMBP), milled at 5.9% was used for comparison. Results indicated that 5.9% WMBP was more degradable than the BMBP. Within the BMBP, the 17% BMBP was more degradable than the 5.9 and the 9.5% BMBP. No differences in nutrient degradability were observed between the 5.9 and the 9.5% BMBP. Key words: Barley, wheat, milling byproducts, nutrient degradability

Case–control evaluation of the impact of below 20 mmHg elastic compression stockings on lower limb volume serial variations in standardized flights

2019 ◽  
Vol 35 (3) ◽  
pp. 199-206 ◽  
Author(s):  
Sergio Gianesini ◽  
Giovanni Mosti ◽  
Joseph D Raffetto ◽  
Elisa Maietti ◽  
Yung-Wei Chi ◽  
...  
Keyword(s):  
Compression Stocking ◽  
Interface Pressure ◽  
Compression Stockings ◽  
Elastic Band ◽  
Volume Increase ◽  
Prolonged Sitting ◽  
The Subject ◽  
Control Evaluation ◽  
The Impact ◽  
Volume Decrease

Background Graduated compression stocking (GCS) use during flights demonstrated to positively impact leg oedema. Nevertheless, these data were collected in a single flight, mainly at the ankle, and using greater than 20 mmHg GCS. This investigation reports data from 16 flights in which the same passenger’s leg circumferences variation were assessed wearing non-graduated ankle-sock or a below-knee 15–20 mmHg GCS. Methods The limb was divided by the circumferences in eight sectors, every 4 cm, labelled from 1 to 8, starting from the ankle up. The assessment was done at the take-off and after a 4-h flight time, for a total of 16 flights. The subject used non-graduated ankle socks (elastic band at 4 cm from B-point) during the outgoing flight and below-knee GCS (15–20 mmHg) during the return flight. Interface pressure was assessed at the ankle point of minimum girth (B) and ascending proximally every 4 cm (B+cm) for the GCS, and at B and at the elastic band level (B + 4 cm) for the sock. Results GCS interface pressure was 13.3 ± 2.5 mmHg in B and 18.1 ± 2.4 mmHg in B + 4 cm. The sock interface pressure was 3.1 ± 0.7 mmHg in B and 8.1 ± 0.9 mmHg at the band level (B + 4 cm). Socks led to a significant total volume increase (117.3 ± 25.8 mL; 5.2% ±1.1%; P < 0.0001). GCS led to a non-significant total volume decrease (–3.1 ± 14.4 mL; –0.1 ± 0.6%; P = 0.3964) and did not allow for volume increase. The different sectors showed a heterogeneous volume variation, not following a precisely graduated or progressive compression profile. Conclusions Leg oedema following a 4-h flight is controlled by <20 mmHg GCS. Leg fluids, with and without GCS, are mobilized in a non-graduated profile from the ankle to the knee after prolonged sitting on a plane.

Comparison of stiffness and interface pressure during rest and exercise among various arm sleeves

2010 ◽  
Vol 25 (4) ◽  
pp. 196-200 ◽  
Author(s):  
M Hirai ◽  
K Niimi ◽  
H Iwata ◽  
I Sugimoto ◽  
H Ishibashi ◽  
...  
Keyword(s):  
Pressure Difference ◽  
Pressure Transducer ◽  
Pressure Amplitude ◽  
Interface Pressure ◽  
Maximal Opening ◽  
High Level ◽  
Opening And Closing ◽  
Contraction And Relaxation ◽  
Rest And Exercise

Objectives To compare the interface pressure during rest and exercise among various kinds of arm sleeves. Methods The interface pressure underneath nine different arm sleeves was measured during 10 maximal opening and closing movements of fingers using a pressure transducer (Air Pack Type Analyser) in 16 healthy volunteers. Furthermore, in order to evaluate the characteristics of each arm sleeve, the extensibility, stiffness and thickness were determined in vitro by several apparatuses. Results There was a significant correlation between stiffness and extensibility. The stiffness was significantly correlated with the pressure difference between muscle contraction and relaxation during exercise. The higher the value of stiffness, the greater the pressure amplitude during exercise. Conclusion Short-stretch arm sleeves characterized with a high level stiffness, including thick round- and flat-knitted arm sleeves, are more beneficial for the augmentation of muscle pumping than long-stretch arm sleeves, in the same way as short-stretch bandages or stockings applied to the leg.

scholarly journals Longer-Term Postcure Measurement of Cuspal Deformation Induced by Dimensional Changes in Dental Materials

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
A. Falsafi ◽  
J. D. Oxman ◽  
P.-H. Tse ◽  
T. T. Ton
Keyword(s):  
Dental Materials ◽  
Displacement Transducer ◽  
Linear Variable Differential Transformer ◽  
Measuring Instrument ◽  
Direct Examination ◽  
Dimensional Changes ◽  
In Situ Techniques ◽  
Oral Conditions

Aim. This paper presents a simple, versatile in vitro methodology that enables indirect quantification of shrinkage and expansion stresses under clinically relevant conditions without the need for a dedicated instrument.Methods. For shrinkage effects, resulting cusp deformation of aluminum blocks with MOD type cavity, filled with novel filling compositions and commercial cements, has been measured using a bench-top micrometer and a Linear Variable Differential Transformer (LVDT, a displacement transducer) based instrument.Results. The results demonstrated the validity of the proposed simple methodology. The technique was successfully used in longer-term measurements of shrinkage and expansion stress for several dental compositions.Conclusions. In contrast to in situ techniques where a measuring instrument is dedicated to the sample and its data collection, the proposed simple methodology allows for transfer of the samples to the environment of choice for storage and conditioning. The presented technique can be reliably used to quantify stress development of curing materials under clinically relevant (oral) conditions. This enables direct examination and comparison of structural properties corresponding to the final stage of formed networks. The proposed methodology is directly applicable to the study of self-curing systems as they require mouth-type conditions (temperature and humidity) to achieve their designed kinetics and reactions.

scholarly journals In vitro and in situ techniques yield different estimates of ruminal disappearance of barley

2019 ◽  
Vol 4 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Mary E DeFeo ◽  
Kelsey V Shampoe ◽  
Pedro H V Carvalho ◽  
Flavia A S Silva ◽  
Tara L Felix
Keyword(s):  
Repeated Measures ◽  
Neutral Detergent Fiber ◽  
Laboratory Methods ◽  
Hulless Barley ◽  
In Vitro Techniques ◽  
In Situ Techniques ◽  
In Vitro Incubation ◽  
Ruminal Degradation

Abstract Objectives were to compare in vitro and in situ disappearance of dry matter (DM), neutral detergent fiber (NDF), and starch of traditional (unprocessed and rolled) and hulless (unprocessed) barley. Experiment 1: three barley sources were compared using in vitro techniques. The sources were: 1) traditional barley that was not processed, 2) traditional barley processed through a roller mill, and 3) hulless barley that was not processed. For in vitro incubation, each barley source was ground through a 1-mm screen. Ground barley sources were weighed into bags (25 micron porosity) and incubated in ruminal fluid from two steers fed 80% rolled corn for 3, 6, 12, 24, 48, or 72 h. Intact bags were assayed for NDF; remaining bags were opened and the residual was removed and analyzed to determine disappearance of DM and starch. Experiment 2: the barley sources used in Exp. 1 were compared using in situ techniques. For in situ analysis, each barley source was ground in a Wiley mill with no screen to mimic mastication. Artificially masticated samples were weighed into Dacron bags (50 ± 10 micron porosity) and incubated in eight ruminally fistulated steers (n = 8) for 3, 6, 12, 24, 48, and 72 h. Residual contents were analyzed to determine in situ disappearance of DM, NDF, and starch. Data were analyzed using the MIXED procedures of SAS (9.4 SAS Institute, Cary, NC) with repeated measures. DM disappearance was greatest (P &lt; 0.05) for hulless barley in vitro and for rolled barley in situ, regardless of time postincubation. For both trials, NDF disappearance was greatest (P &lt; 0.05) for hulless barley, regardless of time postincubation. Starch disappearance at all time points was greatest (P &lt; 0.05) for rolled barley in situ. Starch disappearance was greater (P &lt; 0.05) for hulless barley at 6 h of in vitro incubation compared to rolled and unprocessed barley, whereas starch disappearance in vitro was comparable (P = 0.60) between barley sources. When the grains were compared in vitro, minor differences were noted, presumably because barley sources were finely ground prior to incubation. Compared to in vitro estimates, in situ techniques had greater variation in ruminal degradation estimates. Differences observed between in situ and in vitro techniques are driven largely by differences between the procedures. Although laboratory methods are widely used to estimate ruminal degradation, these techniques did not provide comparable estimates of ruminal degradation of barley.

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