Are interatrial band myocytes maximally hypertrophied in normal canine hearts?

1998 ◽  
Vol 275 (4) ◽  
pp. H1225-H1235
Author(s):  
Paul C. Dolber ◽  
Robert P. Bauman ◽  
Judith C. Rembert ◽  
Joseph C. Greenfield
Keyword(s):  
Cross Sectional Area ◽  
The Other ◽  
Right Atrial ◽  
Sectional Area ◽  
Atrial Myocytes ◽  
Maximal Volume ◽  
Cross Sectional ◽  
Other Hand ◽  
Volume Curve ◽  
Atrial Myocyte

In canine right atrial hypertrophy, the cross-sectional area ( A xs) of right atrial myocytes increases, whereas the A xs of the broader interatrial band myocytes does not. In the current study, myocyte reconstructions showed that right atrial myocyte length increased in proportion to A xs in right atrial hypertrophy. On the other hand, mean interatrial band myocyte length in both normal and right atrial hypertrophy dogs was roughly inversely proportional to mean A xs, as expected if interatrial band myocyte volume was constant. Plotting mean A xs vs. myocyte length for individual interatrial band myocytes revealed a distribution whose border defined a maximal volume curve; many myocytes were well beneath that curve. Mononuclear myocytes (generally diploid) were limited by a 65,000-μm3 curve, which many binuclear myocytes (generally tetraploid) surpassed; myocyte ploidy thus constrained myocyte volume. However, because many mononuclear and binuclear myocytes had lower volumes, their failure to hypertrophy cannot be attributed to attainment of the maximal volume possible for their ploidy.

CFD Solution of a Two-Canopy Parachute in a Top-to-Top Formation With a Vent of Air From One of Its Canopy

2008 ◽  
Author(s):  
Mohammad J. Izadi
Keyword(s):  
Cross Sectional Area ◽  
The Body ◽  
The Other ◽  
Bluff Bodies ◽  
Variable Cross ◽  
Sectional Area ◽  
Cross Sectional ◽  
Drag Forces ◽  
Varied Form ◽  
Two Bodies

A CFD study of a 3 Dimensional flow field around two bodies (Two Canopies of a Parachutes) as two bluff bodies in an incompressible fluid (Air) is modeled here. Formations of these two bodies are top-to-top (One on the top of the other) with respect to the center of each other. One canopy with a constant cross sectional area with a vent of air at its apex, and the other with a variable cross sectional area with no vent is studied here. Vertical distances of these two bodies are varied form zero to half, equal, double and triple radius of the body with a vent on it. The flow condition is considered to be 3-D, unsteady, turbulent, and incompressible. The vertical distances between the bluff bodies, cross sectional area, and also vent ratio of bluff bodies are varied here. The drag forces with static pressures around the two bodies are calculated. From the numerical results, it can be seen that, the drag coefficient is constant on the range of zero to twenty percent of the vent ratio and it decreases for higher vent ratios for when the upper parachute is smaller than the lower one, and it increases for when the upper parachute is larger than the lower one. Both Steady and Unsteady cases gave similar results especially when the distance between the canopies is increased.

The thickness and collagen content of tendon relative to the strength and cross-sectional area of muscle

1965 ◽  
Vol 162 (986) ◽  
pp. 137-146 ◽  
Keyword(s):  
Fibrous Tissue ◽  
Cross Sectional Area ◽  
The Other ◽  
Sectional Area ◽  
Cross Sectional ◽  
Maximum Tension ◽  
White Type ◽  
Fusiform Muscle ◽  
Mechanical Influence ◽  
Tendon Collagen

The orientation of fibrous tissue in tendon suggests a mechanical influence upon the growth of collagen, but in adult rabbits no strict correlation was found between the thickness of certain tendons and the strength of their muscles. The maximum tension transmitted by the collagen in tendons of three fusiform muscles was over fifty per cent greater than that transmitted by the same amount of tendon collagen in three penniform muscles. A similar though smaller difference between these two groups was found in the thickness of their tendons relative to the cross-sectional area of their muscle fasciculi. The tendon of a slow, red, fusiform muscle was relatively thicker than those of the other muscles which were all of the fast, white type.

scholarly journals Could TDX-1 explain the changes observed in endocrine pancreas due to chronic cola drink consumption in rats? A global point of view

2020 ◽  
Author(s):  
Gabriel Cao ◽  
Julián González ◽  
Juan P. Ortiz Fragola ◽  
Angélica Muller ◽  
Mariano Tumarkin ◽  
...  
Keyword(s):  
Body Weight ◽  
Glucose Tolerance ◽  
Islet Cells ◽  
Cross Sectional Area ◽  
The Other ◽  
Cell Area ◽  
Sectional Area ◽  
Β Cells ◽  
Β Cell ◽  
Cross Sectional

AbstractIn previous studies, we reported evidence showing that chronic cola consumption in rats impairs pancreatic metabolism of insulin and glucagon and produces some alterations typically observed in the metabolic syndrome (i.e, hyperglycemia, and hypertriglyceridemia) with an increase in oxidative stress. Of note, no apoptosis nor proliferation of islet cells could be demonstrated. In the present study, 36 male Wistar rats were divided in three groups to freely drink regular cola, light cola, or water (controls). We assessed the impact of the three different beverages in glucose tolerance, lipid levels, creatinine levels and immunohistochemical changes addressed for the expression of insulin, glucagon, PDX-1 and NGN3 in islet cells, to evaluate the possible participation of PDX-1 in the changes observed in α and β cells after 6 months of treatment. On the other hand, we assessed by stereological methods, the mean volume of islets (Vi) and three important variables, the fractional β-cell area, the cross-sectional area of alpha (A α-cell) and beta cells (A β-cell), and the number of β and α cell per body weight.Cola drinking caused impaired glucose tolerance as well as fasting hyperglycemia and increase of insulin immunolabeling. Immunohistochemical expression for PDX-1 was significantly high in regular cola consumption group compared to control. In this case, we observed cytoplasmatic and nuclear localization. Likewise, a mild but significant decrease of Vi was detected after 6 months of cola drink consumption compared with control group. Also, we observed a significant decrease of fractional β cell area compared with control rats. Accordingly, a reduced mean value of islet α and β cell number per body weight compared to control was detected. Interestingly, consumption of light cola increased the Vi compared to control. In line with this, a decreased cross-sectional area of β-cells was observed after chronic consumption of both, regular and light cola, compared to controls. On the other hand, NGN3 was negative in all three groups. Our results support for the first time, the idea that TDX-1 plays a key role in the dynamics of the pancreatic islets after chronic consumption of sweetened beverages. The loss of islets cells might be attributed to autophagy, favored by the local metabolic conditions.

Valsalva's maneuver revisited: a quantitative method yielding insights into human autonomic control

1996 ◽  
Vol 271 (3) ◽  
pp. H1240-H1249 ◽  
Author(s):  
M. L. Smith ◽  
L. A. Beightol ◽  
J. M. Fritsch-Yelle ◽  
K. A. Ellenbogen ◽  
T. R. Porter ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Cross Sectional Area ◽  
Neuronal Firing ◽  
Right Atrial ◽  
Sectional Area ◽  
Nerve Activity ◽  
Cross Sectional ◽  
Muscle Nerve ◽  
Peripheral Arterial ◽  
Valsalva’S Maneuver

Seventeen healthy supine subjects performed graded Valsalva maneuvers. In four subjects, transesophageal echographic aortic cross-sectional areas decreased during and increased after straining. During the first seconds of straining, when aortic cross-sectional area was declining and peripheral arterial pressure was rising, peroneal sympathetic muscle neurons were nearly silent. Then, as aortic cross-sectional area and peripheral pressure both declined, sympathetic muscle nerve activity increased, in proportion to the intensity of straining. Poststraining arterial pressure elevations were proportional to preceding increases of sympathetic activity. Sympathetic inhibition after straining persisted much longer than arterial and right atrial pressure elevations. Similarly, R-R intervals changed in parallel with peripheral arterial pressure, until approximately 45 s after the onset of straining, when R-R intervals were greater and arterial pressures were smaller than prestraining levels. Our conclusions are as follows: opposing changes of carotid and aortic baroreceptor inputs reduce sympathetic muscle and increase vagal cardiac motor neuronal firing; parallel changes of barorsensory inputs provoke reciprocal changes of sympathetic and direct changes of vagal firing; and pressure transients lasting only seconds reset arterial pressure-sympathetic and -vagal response relations.

scholarly journals On a method of determining the viscosity of gases, especially those available only in small quantities

1910 ◽  
Vol 83 (562) ◽  
pp. 265-276 ◽  
Keyword(s):  
Volume Content ◽  
Capillary Tube ◽  
Cross Sectional Area ◽  
The Other ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fine Capillary ◽  
The Difference ◽  
Absolute Measurements ◽  
Unlimited Amount

The apparatus about to be described was designed for the purpose of comparing the viscosities of neon, xenon, and krypton—the loan of which Sir William Ramsay kindly offered the author—with that of air. With such small quantities of gas available, the volume content of the apparatus must obviously be correspondingly small, and therefore, it would seem, unsuitable for absolute measurements. The object of the present paper is to show that this is by no means the case. As will be seen later, the method is actually restricted to small quantities by the conditions of the experiments, but there is no reason why it should not be used even when the gas under test may be obtained in practically unlimited amount. Theory of the Method . Consider a closed glass vessel (as in fig. 1) consisting of two connected limbs, one a fine capillary tube and the other of much greater cross-sectional area, yet sufficiently narrow for a pellet of mercury to remain intact in it. Let V be the volume unoccupied by mercury (the volume of the capillary tube being considered negligible). Let P denote the steady pressure of the gas in the tube when the latter is held horizontally, and let p be the difference of pressure caused by the mercury pellet when the apparatus is vertical. Let p 1 be the pressure and v 1 the volume at any time above the mercury, and p 2 , v 2 , the corresponding quantities below the mercury. Then V = v 1 + v 2 , and p 2 - p 1 = p .

scholarly journals Evaluation of several less known pear (Pyrus communis L.) cultivars in the climatic conditions of Lower Silesia

2012 ◽  
Vol 65 (4) ◽  
pp. 157-162 ◽  
Author(s):  
Ireneusz Sosna ◽  
Daria Kortylewska
Keyword(s):  
Fruit Quality ◽  
Total Yield ◽  
Climatic Conditions ◽  
Cross Sectional Area ◽  
The Other ◽  
Sectional Area ◽  
Cross Sectional ◽  
Experimental Station ◽  
Pyrus Communis L ◽  
Lower Silesia

The aim of this study was to evaluate flowering, yielding, fruit quality, and growth of several less known pear cultivars growing in the climatic conditions of Lower Silesia. The experiment was conducted in the years 2006–2010 in the Fruit Experimental Station located in Samotwór near Wrocław. In spring 2006, trees of several less known pear cultivars were planted: 'Isolda', 'Hortensia', 'Fertilia Delbard Delwilmor', 'Wyżnica', 'Nojabrskaja' ('Xenia®'), 'Uta', 'David' on Caucasian pear (<em>Pyru</em><em>s caucasica </em>Fed.), 'Bohemica' on quince S1 (<em>Cydoni</em><em>a oblonga </em>Mill.) as well as 'Morava' and 'Blanka' on both these rootstocks. The highest total yield in the years 2007–2010 was recorded for the 'Nojabrskaja' and 'Wyżnica' cultivars. The 'Blanka' cultivar produced the largest fruit, while fruits of the 'Isolda' cultivar were significantly the smallest. The largest growth and cross-sectional area of the trunk were recorded for the trees of the 'Wyżnica' cultivar, while the smallest were observed in the case of 'Morava', in which the thickness of the trunk was similar on both rootstocks. The 'Morava' cultivar grafted on quince S1 formed the smallest crowns. On the other hand, 'Isolda' and 'Hortensia' were among the cultivars that produced the largest crowns.

Configuration of maximum expiratory flow-volume curve: model experiments with physiological implications

1985 ◽  
Vol 58 (4) ◽  
pp. 1305-1313 ◽  
Author(s):  
O. F. Pedersen ◽  
R. H. Ingram
Keyword(s):  
Lung Volume ◽  
Cross Sectional Area ◽  
Flow Volume ◽  
Sectional Area ◽  
Cross Sectional ◽  
Frictional Loss ◽  
Partial Obstruction ◽  
Peripheral Airways ◽  
Volume Curve ◽  
Expiratory Flow

A two-compartment mechanical model of the lungs was constructed with two parallel peripheral and collapsible bronchi in series with one central and collapsible trachea. Maximal expiratory flow-volume (MEFV) curves similar to those obtained in most dogs and in some humans could be produced: a peak followed by a gently sloping plateau ending in a knee, where flow suddenly fell to a much smaller value approaching zero rather slowly over the last 25 to 50% of the expired vital capacity. It was shown that flow before the knee was limited in the trachea, and after the knee it was limited in the bronchi. Two patterns of changes in the configuration of the MEFV curve could be observed. Pattern of changes affecting the central airway, at a given volume, maximal flow during the first part of the expiration (i.e., before the knee) is decreased; the knee occurs at a lower lung volume; the flow at the beginning of the knee is decreased. This pattern was observed with the following interventions: decreased cross-sectional area of the trachea (partial obstruction); decreased axial tension of the trachea; and, increased frictional loss between the trachea and the bronchi. Pattern of changes affecting the airways in the periphery: the knee occurs at a higher lung volume; at a given volume, flow after the knee becomes smaller; the absolute flow at the start of the knee is almost unchanged. This pattern was observed with the following interventions: decreased cross-sectional area of the peripheral airways (partial obstruction); increased frictional loss upstream to the peripheral airways; and, decreased elastic recoil pressure.

scholarly journals Yield efficiency for nine apple cultivars grafted on two rootstocks

2016 ◽  
Vol 46 (10) ◽  
pp. 1701-1706 ◽  
Author(s):  
João Caetano Fioravanço ◽  
Ana Beatriz Costa Czermainski ◽  
Paulo Ricardo Dias de Oliveira
Keyword(s):  
Apple Tree ◽  
Cross Sectional Area ◽  
The Other ◽  
High Yield ◽  
Lower Amount ◽  
Sectional Area ◽  
Cross Sectional ◽  
Yield Efficiency ◽  
The Third ◽  
Apple Cultivars

ABSTRACT: Currently, using smaller trees is one of the most important trends in apple cultivation. It is expected that reduced size plants produce lower amount of fruit, but with high yield and yield efficiency. The aim of this study was to evaluate the yield efficiency (YE) of nine apple tree cultivars, grafted on two rootstocks, from the second to the seventh year after planting. The YE indexes oscillated from one to the other year, regardless of rootstock. Correlations between YE and yield per tree and between YE and trunk cross sectional area (TCSA) confirmed that efficiency can be increased by the production increment or by the plant's vigor reduction. The usefulness of cumulative YE (ƩYE) is highlighted to compare apple tree cultivars after the third year of production. The highest ƩYE indexes were observed for 'Royal Gala' and 'Baigent', on M-9 rootstock, and for 'Gala Real' and 'Maxi-Gala', on Marubakaido/M-9 rootstock.

Relative Values of Various Standardized Passages in the Nasometric Assessment of Patients with Velopharyngeal Impairment

1992 ◽  
Vol 29 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Rodger M. Dalston ◽  
Earl J. Seaver
Keyword(s):  
Relevant Information ◽  
Cross Sectional Area ◽  
Performance Data ◽  
The Other ◽  
Clinical Judgments ◽  
Sectional Area ◽  
Cross Sectional

A series of 155 patients referred for evaluation at the UNC Craniofacial Center was studied to compare nasometric performance data obtained from the Rainbow Passage to information provided when subjects read two other standardized passages (Zoo Passage and Nasal Sentences). Nasometric findings obtained using the three reading passages were compared to aerodynamic estimates of velopharyngeal area and nasal cross-sectional area as well as clinical judgments of hypernasality and hyponasality. The results suggest that the Rainbow Passage does not provide clinically relevant information that cannot be obtained using the other speech samples studied.

Pelvic Canal Narrowing Caused by Triple Pelvic Osteotomy in the Dog

1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani
Keyword(s):  
Postoperative Complications ◽  
Pelvic Osteotomy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Canal Width ◽  
Operative Complications ◽  
Post Operative Complications

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.

Sign in / Sign up

Export Citation Format

Share Document