scholarly journals Assessing the accuracy of ultrasound measurements of tracheal diameter: an in vitro experimental study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ran Ye ◽  
Feifei Cai ◽  
Chengnan Guo ◽  
Xiaocheng Zhang ◽  
Dan Yan ◽  
...  
Keyword(s):  
Strong Correlation ◽  
Cuff Pressure ◽  
Close Correlation ◽  
Percentage Change ◽  
Tracheal Wall ◽  
Ultrasound Measurement ◽  
Poor Correlation ◽  
Transverse Diameter ◽  
Cuff Inflation

Abstract Background Recent studies indicate that ultrasound can detect changes in tracheal diameter during endotracheal tube (ETT) cuff inflation. We sought to assess the accuracy of ultrasound measurement of tracheal diameter, and to determine the relationship between tracheal wall pressure (TWP), cuff inflation volume (CIV), and the degree of tracheal deformation. Methods Our study comprised two parts: the first included 45 porcine tracheas, the second 41 porcine tracheas. Each trachea was intubated with a cuffed ETT, which was connected to an injector and the manometer via a three-way tap. The cuff was inflated and the cuff pressure recorded before and after intubation. The tracheal diameter was measured using ultrasound. This included three separate measurements: outer transverse diameter (OTD), internal transverse diameter (ITD), and anterior tracheal wall thicknesses (ATWT). A precision electronic Vernier caliper was also used to measure tracheal diameter. We calculated TWP and the percentage change of tracheal diameter. The Bland–Altman method, linear regression, and locally weighted regression (LOESS) were used to analyze the data. Results There were strong correlation and agreement for OTD (r = 0.97, P < 0.001) and ITD (r = 0.90, P < 0.001) as measured by ultrasound and by precision electronic Vernier caliper, but a poor correlation for ATWT (r = 0.58, P < 0.001). There was a strong correlation between the percentage change of OTD (OTD%, r = 0.75, P < 0.001) and CIV, the percentage change of ITD (ITD%, r = 0.77, P < 0.001) and CIV, TWP (r = 0.75, P < 0.001) and CIV. And a strong correlation was also found between TWP and OTD% (r = 0.84, P < 0.001), TWP and ITD% (r = 0.84, P < 0.001). Conclusions Use of ultrasound to measure OTD and ITD is accurate, but is less accurate for ATWT. There is a close correlation between OTD%, ITD%, CIV and TWP.

The efficacy of sinus plication in aortic valvuloplasty for bicuspid aortic valve: experiments in a pulsatile flow simulation model

2021 ◽  
Author(s):  
Satoshi Arimura ◽  
Jumpei Takada ◽  
Gohki Nishimura ◽  
Natsuki Nakama ◽  
Eita Kawasaki ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Bicuspid Aortic Valve ◽  
Pulsatile Flow ◽  
Flow Simulation ◽  
Ultrasound Measurement ◽  
Hydrodynamic Effect ◽  
Promising Tool ◽  
Aortic Valvuloplasty ◽  
Flow Simulator

Abstract OBJECTIVES Sinus plication has emerged as a promising tool that can lead to better stability in bicuspid aortic valve (BAV) repair. However, the mechanisms underlying the efficacy of this technique are unclear. We evaluated the hydrodynamic effect of sinus plication using the experimental pulsatile flow simulator and our original BAV model in vitro. METHODS Based on the computed tomography data of a BAV patient who had undergone aortic valvuloplasty, a BAV model (group C, n = 6) was developed with bovine pericardium and vascular prosthesis (J-graft Shield Neo Valsalva 24 mm). We performed sinus plication (group SP, n = 6) in the BAV model and compared hydrodynamic data with the control model in the pulsatile flow simulator. Non-fused cusp angle, annulus diameter and effective height were measured by ultrasonography. RESULTS The average flow was significantly increased in group SP compared to group C (4.24 ± 0.14 l/min vs 4.14 ± 0.15 l/min, respectively, P = 0.034). The mean transvalvular pressure gradient and regurgitant fraction were significantly decreased in group SP compared to group C (11.6 ± 4.3 mmHg vs 16.6 ± 5.0 mmHg, respectively, P = 0.009 and 14.1 ± 2.0% vs 17.4 ± 2.1%, respectively, P = 0.001). Ultrasound measurement indicated that non-fused cusp angle was significantly increased in group SP compared to group C (163.8° ± 9.2° vs 153.0° ± 4.6°, respectively, P = 0.012). CONCLUSIONS Sinus plication in the BAV model significantly increased the commissural angle. It was effective in not only controlling regurgitation but also improving valve opening. These finding should be confirmed by evaluating cusp stress and/or long-term durability in the future studies.

Regional variation of series elasticity in canine arterial smooth muscles

1978 ◽  
Vol 234 (5) ◽  
pp. H542-H551 ◽  
Author(s):  
R. H. Cox
Keyword(s):  
Stress Response ◽  
Stress Responses ◽  
Regional Variation ◽  
Smooth Muscles ◽  
Muscle Length ◽  
Close Correlation ◽  
Contractile Element ◽  
Active Stress ◽  
Elastic Elements

Segments of carotid, iliac, renal, mesenteric, coronary, and internal thoracic arteries were studied in vitro to correlate the mechanical properties of series (SE) and parallel (PE) elastic elements with connective tissue (CT) composition and with active responses to potassium activation. The PE properties were determined using pressure-diameter data with passive smooth muscle (SM). SE properties were determined from periodic incremental releases imposed during isometric responses to [K+]O at a diameter corresponding to Lmax, the optimum muscle length. Active stress responses and diameter responses were determined using pressure-diameter data for active and passive conditions. Collagen and elastin contents were determined for each sample. No correlation was found between CT content and PE or SE properties for the various sites. A close correlation was found to exist between SE and PE properties at each site, i.e., the sites with the stiffest PE also had the stiffest SE. SM, with stiffer SE, had a larger diameter response with the same active stress response and the same diameter response with a smaller active stress response, compared to SM with more compliant SE. This suggests that passive properties of SM can have a significant influence on the external manifestations of contractile element properties.

Antiplatelet Effect Of A New Compound, Imidazo[1,2-a]- Thienopyrimidin-2-One : A Cyclic AMP Mediated Phenomenon

1981 ◽  
Author(s):  
S Ashida ◽  
K Sakuma ◽  
Y Abiko
Keyword(s):  
Platelet Aggregation ◽  
Membrane Fraction ◽  
Close Correlation ◽  
Inhibitory Effect ◽  
Camp Level ◽  
Camp Phosphodiesterase ◽  
Pde Inhibitors ◽  
Camp Metabolism ◽  
Oral Doses

The effect of a new compound, 1,2,3,5,6,7,8,9-Octahydro- [1]benzothieno[2,3-d]imidazo[1,2-a]pyrimidin-2-one hydrochloride (DH-6471), on cAMP metabolism and aggregation of platelets was studied. In vitro. DH-6471 inhibited platelet aggregation (both the 1st and 2nd phases) induced by ADP, collagen, thrombin, arachidonic acid and PGG2-TXA2 mixture in PRP from various animal species including human at concentrations (IC50) ranging from 0.07 to 8 μH. It inhibited ADP- and collagen-induced platelet aggregation ex vivg in rats following oral doses as low as 0.3- 1 mg/kg.The compound was found to be a highly selective inhibitor of platelet low Km cAMP phosphodiesterase (Ki=0.025 μM), when tested with enzyme fractions separated by DEAE-cellu-lose chromatography. It did not significantly affect basal or PGE1(0.1-1 μM)-stimulated cAMP level of platelets at a concentration of 1 μM where platelet aggregation and the low Km PDE were markedly inhibited. However, both basal and PGE1-stimulated accumulations of cAMP in the platelet membrane fraction were increased by DH-6471 at 1 μM when the isolated membrane fraction was incubated with ATP-Mg2+.Studies with several PDE inhibitors including papaverine, dipyridamole and DH-6471-related compounds showed a close correlation between their ability to inhibit the low Km PDE or to increase cAMP accumulation in the membrane fraction and their inhibitory effect on platelet aggregation. On the other hand, their potency to inhibit high Km cAMP-PDE(cGMP-PDE) and to increase cAMP level in whole platelets was poorly correlated to their inhibitory activity in platelet aggregation.These results suggest that some small but local changes in platelet cAMP may be involved in the regulation of platelet aggregation, particularly primary aggregation.

Parameters and Methods for Testing Artificial Heart Valves

1989 ◽  
Vol 12 (4) ◽  
pp. 252-260 ◽  
Author(s):  
J.C. Köhler ◽  
J.G. Tech
Keyword(s):  
Heart Valves ◽  
Close Correlation ◽  
Test Methods ◽  
In Vitro Tests ◽  
Geometrical Parameters ◽  
Test Standards ◽  
Artificial Heart Valves ◽  
Minimum Requirements ◽  
Definition Of

The report describes the development of heart valve test standards. The aim is comprehensive quality assurance by in vitro tests. The project includes three test fields: general basis, development and definition of test methods and test devices and comparative in vitro assessment of valves for the definition of minimum requirements. A preliminary list of test parameters and test steps has been defined: geometrical, flow, deformation, force, and conditioning parameters. A system of geometrical parameters has been developed for standardized aortic models. Geometrical parameters of 31 valves of six types and different sizes underline a close correlation between geometrical and hemodynamic parameters. The relative ostium cross-section Ae/AT increases with valve size and lies between 0.3 and 0.5. Two new measurement devices with quasi-steady flow are proposed as quick testers for leakage flow and pressure loss.

scholarly journals Primary leukemia cells resistant to alpha-interferon in vitro are defective in the activation of the DNA-binding factor interferon- stimulated gene factor 3

Blood ◽  
1994 ◽  
Vol 84 (6) ◽  
pp. 1942-1949 ◽  
Author(s):  
B Xu ◽  
D Grander ◽  
O Sangfelt ◽  
S Einhorn
Keyword(s):  
Close Correlation ◽  
Lymphocytic Leukemia ◽  
Alpha Interferon ◽  
Leukemia Cells ◽  
Blast Transformation ◽  
Oligoadenylate Synthetase ◽  
Binding Factor ◽  
Ifn Treatment ◽  
Possible Cause

Abstract Cells from one-third of chronic lymphocytic leukemia (CLL) patients are resistant to alpha-interferon (alpha-IFN) as measured by induction of blast transformation. We have previously shown that all CLL clones express alpha/beta-IFN receptors, but that the resistant cells are defective in the induction of the enzyme 2′,5′-oligoadenylate synthetase (2′,5-A synthetase). Thus, the deficiency in IFN sensitivity is localized somewhere between the interaction of the IFN molecule with its receptor and induction of 2′,5′-A synthetase. We have now further characterized the resistance of CLL clones to IFN by investigating whether it is associated with a defect in the activation of IFN- stimulated gene factor 3 (ISGF3), which is involved in the activation of alpha-IFN-stimulated genes (ISGs). A defect induction of ISGF3 after alpha-IFN treatment was found in 4 of 12 CLL patients. There was a close correlation between defective induction of ISGF3 and a lack of enhancement of 2′,5′-A synthetase as well as induction of blast transformation. Pretreatment with gamma-IFN and mixing experiments with extracts from IFN-sensitive cells indicate that a lack of the gamma- component of ISGF3 was the reason for defect in activation in 2 of the patients. We conclude that a defect in activation of ISGF3 is a possible cause for resistance in CLL cells to IFN-induced blast transformation in vitro.

scholarly journals Ricin binding and protein synthesis inhibition in human hematopoietic cell lines

Blood ◽  
1988 ◽  
Vol 72 (4) ◽  
pp. 1357-1363 ◽  
Author(s):  
JE Leonard ◽  
CD Grothaus ◽  
R Taetle
Keyword(s):  
Cell Surface ◽  
Cell Lines ◽  
Close Correlation ◽  
Hematopoietic Cell ◽  
Protein Synthesis Inhibition ◽  
Human Blood Cells ◽  
Kd Values ◽  
Membrane Bound ◽  
Hematopoietic Cell Lines

Abstract Previous studies showed that human blood cells exhibited varying sensitivities to ricin. To investigate the basis for these differences, ricin binding to human hematopoietic cell lines was assessed and correlated with in vitro ricin sensitivities. Resistant mutants were also isolated and characterized. Ricin binding to CEM cells was rapid, time-dependent, and blocked by unlabeled ricin, but not albumin; ricin binding approached saturation at 3 mumol/L. Scatchard analyses showed multiple classes of binding sites, with maximum and minimum Kd values estimated at 1.5 x 10(-8) mol/L and 2.5 x 10(-7) mol/L. At 4 degrees C, membrane-bound ricin dissociated slowly from the cell surface in the presence of unlabeled ricin, but greater than 95% of the surface-bound ricin was removed with 0.1 mol/L lactose. At 37 degrees C, ricin dissociated from the cell surface with biphasic kinetics. Ricin uptake at 37 degrees C increased linearly for 15 to 30 minutes and plateaued at levels representing 12% to 29% of the amount of ricin bound at 4 degrees C, depending on the cell line. Ricin binding at 4 degrees C varied two- to fivefold among hematopoietic cell lines and was reduced approximately tenfold by incubation with lactose. When compared with parent CEM cells, ricin-resistant CEM variants showed a greater than 95% reduction in ricin binding and showed no detectable binding with lactose added. However, these cells were as sensitive as parent CEM cells to an anti-T-cell ricin immunoconjugate. For all cells examined, there was a close correlation (r = +.9) between ricin bound per cell and in vitro ricin sensitivity. Human hematopoietic cells show widely varying ricin binding, indicating major differences in the carbohydrate content or structure of surface glycoproteins and glycolipids. These variations are probably the major determinant of nonspecific toxicity of ricin immunoconjugates.

A Model for Non-Invasive Estimation of in Vivo Dialyzer Performances and Patient's Conductivity during Hemodialysis

1993 ◽  
Vol 16 (8) ◽  
pp. 585-591 ◽  
Author(s):  
T. Petitclerc ◽  
N. Goux ◽  
A.L. Reynier ◽  
B. Béné
Keyword(s):  
Strong Correlation ◽  
New Method ◽  
Conductivity Measurements ◽  
Urea Clearance ◽  
Non Invasive ◽  
Model Based ◽  
On Line ◽  
Conventional Methods

On-line monitoring of hemodialysis sessions requires a non-invasive estimation of the parameters concerning the patient's status and the dialyzer performances. We describe here a model based on a new method for non-invasive dialysance and patient conductivity measurements. In this technique the same probe measures alternately the conductivity at the dialysate inlet and outlet for two different dialysate conductivity values. From these data, an appropriate model allows to determine the patient's conductivity as well as the effective dialysance of ionised solutes, that is to say the dialysance corrected for recirculation. A strong correlation is evidenced between the effective dialysance measured by this method and the urea clearance measured by conventional methods (r=0.98 for in vitro solutions; r=0.82 in in vivo situations).

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