Influence of site of regional ischemia on nonischemic thickening in anesthetized dogs

1989 ◽  
Vol 256 (5) ◽  
pp. H1417-H1425
Author(s):  
P. N. Marino ◽  
D. A. Kass ◽  
L. C. Becker ◽  
J. A. Lima ◽  
J. L. Weiss
Keyword(s):  
Myocardial Function ◽  
Three Dimensional ◽  
Cross Sectional ◽  
Regional Ischemia ◽  
Systolic Thickening ◽  
Lv Mass ◽  
Dimensional Distribution ◽  
Anesthetized Dogs ◽  
Acute Regional Ischemia ◽  
Wall Geometry

The effect of varying the site of acute regional ischemia on nonischemic myocardial function was examined by comparing regional thickening during 2-3 min circumflex (Circ) vs. left anterior descending (LAD) coronary artery occlusions in eight open-chest dogs. Cross-sectional midwall two-dimensional echocardiograms were obtained, and systolic thickening was measured at 16 equal-spaced points around the circumference. The distribution and extent of hypoperfusion was assessed by radiolabeled microspheres. The echo slice was subdivided into a hypoperfused region (Hypo), four adjacent nonischemic regions (ADJ1-4), and the remaining remote segments (Remote). The extent of hypoperfusion (%LV mass) was similar with both sets of occlusions (LAD, 29.4 +/- 2.8%; Circ, 26.0 +/- 4.4%; P = NS), as was endo- and epicardial flow in the nonischemic regions. Yet, even with like-sized Hypo regions, thickening of nonischemic myocardium was significantly greater during Circ than during LAD occlusions (P less than 0.001). These results are consistent with recently reported disparities of global functional impairment during LAD vs. Circ ischemia. The responses likely reflect differences in regional wall geometry, loading, and the three-dimensional distribution of coronary hypoperfusion between the two vascular territories.

scholarly journals Three-dimensional molar enamel distribution and thickness in Australopithecus and Paranthropus

2008 ◽  
Vol 4 (4) ◽  
pp. 406-410 ◽  
Author(s):  
A.J Olejniczak ◽  
T.M Smith ◽  
M.M Skinner ◽  
F.E Grine ◽  
R.N.M Feeney ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Two Dimensional ◽  
Cross Sectional ◽  
Enamel Thickness ◽  
Australopithecus Africanus ◽  
Interspecific Differences ◽  
Dimensional Measurements ◽  
Dimensional Distribution ◽  
History Of ◽  
Thickness Measurements

Thick molar enamel is among the few diagnostic characters of hominins which are measurable in fossil specimens. Despite a long history of study and characterization of Paranthropus molars as relatively ‘hyper-thick’, only a few tooth fragments and controlled planes of section (designed to be proxies of whole-crown thickness) have been measured. Here, we measure molar enamel thickness in Australopithecus africanus and Paranthropus robustus using accurate microtomographic methods, recording the whole-crown distribution of enamel. Both taxa have relatively thick enamel, but are thinner than previously characterized based on two-dimensional measurements. Three-dimensional measurements show that P. robustus enamel is not hyper-thick, and A. africanus enamel is relatively thinner than that of recent humans. Interspecific differences in the whole-crown distribution of enamel thickness influence cross-sectional measurements such that enamel thickness is exaggerated in two-dimensional sections of A. africanus and P. robustus molars. As such, two-dimensional enamel thickness measurements in australopiths are not reliable proxies for the three-dimensional data they are meant to represent. The three-dimensional distribution of enamel thickness shows different patterns among species, and is more useful for the interpretation of functional adaptations than single summary measures of enamel thickness.

Small apex-to-base heterogeneity in radius-to-thickness ratio by three-dimensional magnetic resonance imaging

1993 ◽  
Vol 264 (1) ◽  
pp. H133-H140 ◽  
Author(s):  
R. Beyar ◽  
J. L. Weiss ◽  
E. P. Shapiro ◽  
W. L. Graves ◽  
W. J. Rogers ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Ejection Fraction ◽  
Myocardial Function ◽  
Three Dimensional ◽  
Stress Index ◽  
Radius Of Curvature ◽  
Cross Sectional ◽  
Large Variability ◽  
Small Base ◽  
Image Planes

Reported large base-to-apex differences in endocardial area ejection fraction may suggest large variability in myocardial function and load. To test ventricular load heterogeneities, we measured the ratio of radius of curvature to wall thickness (R/T), as a stress index reflecting myocardial load. End-diastolic (ED) and end-systolic (ES) magnetic resonance cross-sectional images were obtained in 15 open-chest dogs at 5 levels from base to apex, from which 4 three-dimensional thick disks were generated from adjacent image planes. The average R/T for each disk was calculated by planar and three-dimensional methods, using both midwall and endocardial radii of curvature. R/T was normalized to the apical value to quantify the relative changes in myocardial load. Normalized R/T using the midwall three-dimensional approach was 1.08, 1.11, 1.06, and 1.0 for ED (P = NS) and 1.25, 1.013, 1.08, and 1.0 for ES (P < 0.02), base to apex, respectively, while the other methods yielded higher values. Therefore, R/T calculated by the three-dimensional midwall approach shows only small apex-to base variations at ED (< 11%) and ES (< 25%), which is substantially less than the variability in area ejection fraction (102%). This suggests only small base-to-apex load heterogeneities, in spite of large changes in the area ejection fraction, an index reflecting specific ventricular geometry rather than local myocardial function.

Piezoelectric polymer curvature sensor for measurement of regional curvature radius of LV wall

1988 ◽  
Vol 254 (5) ◽  
pp. H1010-H1016 ◽  
Author(s):  
K. Tsujioka ◽  
Y. Ogasawara ◽  
K. Mito ◽  
O. Hiramatsu ◽  
Y. Wada ◽  
...  
Keyword(s):  
Myocardial Function ◽  
Accurate Information ◽  
Curvature Radius ◽  
Short Axis ◽  
Regional Myocardial Function ◽  
Regional Ischemia ◽  
Piezoelectric Polymer ◽  
Anesthetized Dogs ◽  
And Function ◽  
Curvature Sensor

To evaluate regional myocardial function, we developed a curvature sensor for direct and instantaneous measurement of the regional curvature radius of the LV wall. The sensor is a bimorph of two sheets of thin piezoelectric polymer film. The relation between output voltage of the sensor and the reciprocal of the known curvature radius has been shown to be linear. In anesthetized dogs, we inserted the curvature sensor into the subepimyocardium with a specially designed introducer. Special care was taken to insert it parallel to the epicardial surface. Circumferential regional curvature radius, which is defined as the reciprocal of regional curvature, showed the same phasic changes as the short-axis diameter under control conditions. Under regional ischemia caused by transient occlusion of the coronary artery, amplitude of the phasic change in regional curvature radius decreased, whereas that of the short-axis diameter did not change or slightly increased. Phasic changes in regional curvature radius cannot be estimated from short-axis diameter during regional ischemia. We calculated regional wall tension from the directly measured regional curvature radius and LV pressure and found that tension-length loop clearly differentiates between regional myocardial function under control and ischemic conditions. We have concluded that our newly developed curvature sensor is accurate, that its practical use is feasible, and that measurement of the regional curvature radius of the LV wall provides detailed and accurate information on regional shape and function of the left ventricle.

Three-dimensional distribution of ribulose-1, 5-bisphosphate carboxylase/oxygemase during the early development of proplastids in dark-grown Euglena cells transferred to an inorganic medium

1990 ◽  
Vol 48 (3) ◽  
pp. 906-907
Author(s):  
Tomoko Ehara ◽  
Shuji Sumida ◽  
Tetsuaki Osafune ◽  
Eiji Hase
Keyword(s):  
Cell Suspension ◽  
Euglena Gracilis ◽  
Carbon Materials ◽  
Three Dimensional ◽  
Peripheral Region ◽  
Plastid Development ◽  
Bisphosphate Carboxylase ◽  
Inorganic Medium ◽  
Ribulose 1 ◽  
Dimensional Distribution

As shown previously, Euglena cells grown in Hutner’s medium in the dark without agitation accumulate wax as well as paramylum, and contain proplastids showing no internal structure except for a single prothylakoid existing close to the envelope. When the cells are transferred to an inorganic medium containing ammonium salt and the cell suspension is aerated in the dark, the wax was oxidatively metabolized, providing carbon materials and energy 23 for some dark processes of plastid development. Under these conditions, pyrenoid-like structures (called “pro-pyrenoids”) are formed at the sites adjacent to the prolamel larbodies (PLB) localized in the peripheral region of the proplastid. The single prothylakoid becomes paired with a newly formed prothylakoid, and a part of the paired prothylakoids is extended, with foldings, in to the “propyrenoid”. In this study, we observed a concentration of RuBisCO in the “propyrenoid” of Euglena gracilis strain Z using immunoelectron microscopy.

scholarly journals Dip angles of active faults from the surface to the seismogenic zone inferred from a 2D numerical analysis of visco-elasto-plastic models: a case study for the Osaka Plain

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Hayami Nishiwaki ◽  
Takamoto Okudaira ◽  
Kazuhiko Ishii ◽  
Muneki Mitamura
Keyword(s):  
Urban Areas ◽  
Active Faults ◽  
Three Dimensional ◽  
Seismogenic Zone ◽  
Earthquake Ground Motion ◽  
Convex Curve ◽  
Seismic Reflection Profile ◽  
Geological Structures ◽  
Dimensional Distribution ◽  
Dip Angle

AbstractThe geometries (i.e., dip angles) of active faults from the surface to the seismogenic zone are the most important factors used to evaluate earthquake ground motion, which is crucial for seismic hazard assessments in urban areas. In Osaka, a metropolitan city in Japan, there are several active faults (e.g., the Uemachi and Ikoma faults), which are inferred from the topography, the attitude of active faults in surface trenches, the seismic reflection profile at shallow depths (less than 2 km), and the three-dimensional distribution of the Quaternary sedimentary layers. The Uemachi and Ikoma faults are N–S-striking fault systems with total lengths of 42 km and 38 km, respectively, with the former being located ~ 12 km west of the latter; however, the geometries of each of the active faults within the seismogenic zone are not clear. In this study, to examine the geometries of the Uemachi and Ikoma faults from the surface to the seismogenic zone, we analyze the development of the geological structures of sedimentary layers based on numerical simulations of a two-dimensional visco-elasto-plastic body under a horizontal compressive stress field, including preexisting high-strained weak zones (i.e., faults) and surface sedimentation processes, and evaluate the relationship between the observed geological structures of the Quaternary sediments (i.e., the Osaka Group) in the Osaka Plain and the model results. As a result, we propose geometries of the Uemachi and Ikoma faults from the surface to the seismogenic zone. When the friction coefficient of the faults is ~ 0.5, the dip angles of the Uemachi and Ikoma faults near the surface are ~ 30°–40° and the Uemachi fault has a downward convex curve at the bottom of the seismogenic zone, but does not converge to the Ikoma fault. Based on the analysis in this study, the dip angle of the Uemachi fault zone is estimated to be approximately 30°–40°, which is lower than that estimated in the previous studies. If the active fault has a low angle, the width of the fault plane is long, and thus the estimated seismic moment will be large.

scholarly journals Accuracy and Reproducibility of Facial Measurements of Digital Photographs and Wrapped Cone Beam Computed Tomography (CBCT) Photographs

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 757
Author(s):  
Maged Sultan Alhammadi ◽  
Abeer Abdulkareem Al-mashraqi ◽  
Rayid Hussain Alnami ◽  
Nawaf Mohammad Ashqar ◽  
Omar Hassan Alamir ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Cone Beam Computed Tomography ◽  
High Reliability ◽  
Three Dimensional ◽  
Cone Beam ◽  
Cross Sectional ◽  
Facial Profile ◽  
Digital Photographs ◽  
Gonial Angle

The study sought to assess whether the soft tissue facial profile measurements of direct Cone Beam Computed Tomography (CBCT) and wrapped CBCT images of non-standardized facial photographs are accurate compared to the standardized digital photographs. In this cross-sectional study, 60 patients with an age range of 18–30 years, who were indicated for CBCT, were enrolled. Two facial photographs were taken per patient: standardized and random (non-standardized). The non-standardized ones were wrapped with the CBCT images. The most used soft tissue facial profile landmarks/parameters (linear and angular) were measured on direct soft tissue three-dimensional (3D) images and on the photographs wrapped over the 3D-CBCT images, and then compared to the standardized photographs. The reliability analysis was performed using concordance correlation coefficients (CCC) and depicted graphically using Bland–Altman plots. Most of the linear and angular measurements showed high reliability (0.91 to 0.998). Nevertheless, four soft tissue measurements were unreliable; namely, posterior gonial angle (0.085 and 0.11 for wrapped and direct CBCT soft tissue, respectively), mandibular plane angle (0.006 and 0.0016 for wrapped and direct CBCT soft tissue, respectively), posterior facial height (0.63 and 0.62 for wrapped and direct CBCT soft tissue, respectively) and total soft tissue facial convexity (0.52 for both wrapped and direct CBCT soft tissue, respectively). The soft tissue facial profile measurements from either the direct 3D-CBCT images or the wrapped CBCT images of non-standardized frontal photographs were accurate, and can be used to analyze most of the soft tissue facial profile measurements.

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