scholarly journals Effect of Malonate, Succinate and Glucose, In Vivo, on the Uptake of Cesium-137 by Pigeon (Columba livia) Muscles

1971 ◽  
Vol 12 (2) ◽  
pp. 56-60 ◽  
Author(s):  
N. NARAYANAN ◽  
Jacob EAPEN
Keyword(s):  
Columba Livia ◽  
Cesium 137

PECTORALIS MUSCLE FORCE AND POWER OUTPUT DURING DIFFERENT MODES OF FLIGHT IN PIGEONS (COLUMBA LIVIA)

1993 ◽  
Vol 176 (1) ◽  
pp. 31-54 ◽  
Author(s):  
K. P. Dial ◽  
A. A. Biewener
Keyword(s):  
Strain Gauge ◽  
Power Output ◽  
Muscle Force ◽  
Columba Livia ◽  
Principal Strain ◽  
Specific Power ◽  
Single Element ◽  
Pectoralis Muscle ◽  
Level Flight

In vivo measurements of pectoralis muscle force during different modes of free flight (takeoff, level flapping, landing, vertical ascending and near vertical descending flight) were obtained using a strain gauge attached to the dorsal surface of the delto-pectoral crest (DPC) of the humerus in four trained pigeons (Columba livia). In one bird, a rosette strain gauge was attached to the DPC to determine the principal axis of strain produced by tension of the pectoralis. Strain signals recorded during flight were calibrated to force based on in situ measurements of tetanic force and on direct tension applied to the muscle's insertion at the DPC. Rosette strain recordings showed that at maximal force the orientation of tensile principal strain was −15° (proximo-anterior) to the perpendicular axis of the DPC (or +75° to the longitudinal axis of the humerus), ranging from +15 to −25° to the DPC axis during the downstroke. The consistency of tensile principal strain orientation in the DPC confirms the more general use of single-element strain gauges as being a reliable method for determining in vivo pectoralis force generation. Our strain recordings show that the pectoralis begins to develop force as it is being lengthened, during the final one-third of the upstroke, and attains maximum force output while shortening during the first one-third of the downstroke. Force is sustained throughout the entire downstroke, even after the onset of the upstroke for certain flight conditions. Mean peak forces developed by the pectoralis based on measurements from 40 wingbeats for each bird (160 total) were: 24.9+/−3.1 N during takeoff, 19.7+/−2.0 N during level flight (at speeds of about 6–9 m s-1 and a wingbeat frequency of 8.6+/−0.3 Hz), 18.7+/−2.5 N during landing, 23.7+/−2.7 N during near-vertical descent, and 26.0+/−1.8 N during vertical ascending flight. These forces are considerably lower than the maximum isometric force (67 N, P0) of the muscle, ranging from 28 % (landing) to 39 % (vertical ascending) of P0. Based on estimates of muscle fiber length change determined from high- speed (200 frames s-1) light cine films taken of the animals, we calculate the mass-specific power output of the pigeon pectoralis to be 51 W kg-1 during level flight (approximately 8 m s-1), and 119 W kg-1 during takeoff from the ground. When the birds were harnessed with weighted backpacks (50 % and 100 % of body weight), the forces generated by the pectoralis did not significantly exceed those observed in unloaded birds executing vertical ascending flight. These data suggest that the range of force production by the pectoralis under these differing conditions is constrained by the force- velocity properties of the muscle operating at fairly rapid rates of shortening (4.4 fiber lengths s-1 during level flight and 6.7 fiber lengths s-1 during takeoff).

In vivo strains in pigeon flight feather shafts: implications for structural design

1998 ◽  
Vol 201 (22) ◽  
pp. 3057-3065 ◽  
Author(s):  
WR Corning ◽  
AA Biewener
Keyword(s):  
Safety Factor ◽  
Tensile Strain ◽  
Columba Livia ◽  
Failure Stress ◽  
Metal Foil ◽  
Bending Tests ◽  
Flight Feather ◽  
Four Point Bending ◽  
The Mean

To evaluate the safety factor for flight feather shafts, in vivo strains were recorded during free flight from the dorsal surface of a variety of flight feathers of captive pigeons (Columba livia) using metal foil strain gauges. Strains recorded while the birds flew at a slow speed (approximately 5-6 m s-1) were used to calculate functional stresses on the basis of published values for the elastic modulus of feather keratin. These stresses were then compared with measurements of the failure stress obtained from four-point bending tests of whole sections of the rachis at a similar location. Recorded strains followed an oscillatory pattern, changing from tensile strain during the upstroke to compressive strain during the downstroke. Peak compressive strains were 2.2+/-0. 9 times (mean +/- s.d.) greater than peak tensile strains. Tensile strain peaks were generally not as large in more proximal flight feathers. Maximal compressive strains averaged -0.0033+/-0.0012 and occurred late in the downstroke. Bending tests demonstrated that feather shafts are most likely to fail through local buckling of their compact keratin cortex. A comparison of the mean (8.3 MPa) and maximum (15.7 MPa) peak stresses calculated from the in vivo strain recordings with the mean failure stress measured in four-point bending (137 MPa) yields a safety factor of between 9 and 17. Under more strenuous flight conditions, feather stresses are estimated to be 1.4-fold higher, reducing their safety factor to the range 6-12. These values seem high, considering that the safety factor of the humerus of pigeons has been estimated to be between 1.9 and 3.5. Several hypotheses explaining this difference in safety factor are considered, but the most reasonable explanation appears to be that flexural stiffness is more critical than strength to feather shaft performance.

scholarly journals Experimental Test of the Importance of Preen Oil in Rock Doves (Columba Livia)

The Auk ◽  
2003 ◽  
Vol 120 (2) ◽  
pp. 490-496 ◽  
Author(s):  
BrettR. Moyer ◽  
Alex N. Rock ◽  
Dale H. Clayton
Keyword(s):  
Experimental Test ◽  
Columba Livia ◽  
Uropygial Gland ◽  
Preen Gland ◽  
In Vivo Experiments ◽  
Preen Oil ◽  
Bacteria And Fungi

Abstract Most species of birds have a uropygial gland, also known as a preen gland, which produces oil that birds spread through their plumage when preening. The plumage of waterfowl deprived of uropygial oil becomes brittle and is subject to breakage. For other groups of birds, however, the importance of preen oil remains unclear. Previous workers have argued that preen oil may serve little or no function in Columbiforms (pigeons and doves). We tested that assertion by removing uropygial glands from Rock Doves (Columba livia) and assessing their plumage condition after several months. The results of that experiment showed significant degradation of plumage in the absence of oil. Our results are the first rigorous demonstration that preen oil is important for plumage condition in nonwaterfowl. We tested one possible function of preen oil—that it has insecticidal properties and that reduction in plumage condition on birds without glands is due to an increase in ectoparasites. We tested that hypothesis for feather-feeding lice (Phthiraptera:Ischnocera) using both in vitro and in vivo experiments. Lice raised in an incubator died more rapidly on feathers with preen oil than on feathers without oil, which suggests that preen oil may help combat lice. However, removal of the preen gland from captive birds had no significant effect on louse loads over the course of a four-month experiment. Although the results of our in vivo experiments suggest that preen oil may not be an important defense against lice, further experiments are needed. We also consider the possibility that preen oil may protect birds against other plumage-degrading organisms, such as bacteria and fungi.

scholarly journals Preparation, Characterization, and In Vivo Pharmacoscintigraphy Evaluation of an Intestinal Release Delivery System of Prussian Blue for Decorporation of Cesium and Thallium

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Nidhi Sandal ◽  
Gaurav Mittal ◽  
Aseem Bhatnagar ◽  
Dharam Pal Pathak ◽  
Ajay Kumar Singh
Keyword(s):  
Prussian Blue ◽  
Delivery System ◽  
Oral Delivery ◽  
Polymer Concentration ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Cesium 137 ◽  
Ph Dependent ◽  
Us Fda

Background. Prussian blue (PB, ferric hexacyanoferrate) is approved by US-FDA for internal decorporation of Cesium-137 (137Cs) and Thallium-201 (201Tl). Aim. Since PB is a costly drug, pH-dependent oral delivery system of PB was developed using calcium alginate matrix system. Methods. Alginate (Alg) beads containing PB were optimized by gelation of sodium alginate with calcium ions and effect of varying polymer concentration on encapsulation efficiency and release profile was investigated. Scanning electron microscopy (SEM) was carried out to study surface morphology. Adsorption efficacy of Alg-PB beads for 201Tl was evaluated and compared with native PB. In vivo pH-dependent release of the formulation was studied in humans using gamma scintigraphy. Results. Encapsulation efficiencies of Alg-PB beads with 0.5, 1.0, 1.5, and 2.0% polymer solution were 99.9, 91, 92, and 93%, respectively. SEM and particle size analysis revealed differences between formulations in their appearance and size distribution. No drug release was seen in acidic media (pH of 1-2) while complete release was observed at pH of 6.8. Dissolution data was fitted to various mathematical models and beads were found to follow Hixson-Crowell mechanism of release. The pH-dependent release of beads was confirmed in vivo by pharmacoscintigraphy in humans.

scholarly journals Chronic cannulation in the small intestine of feral pigeons (Columba livia) to assess bioavailability

2010 ◽  
Vol 55 (No. 8) ◽  
pp. 383-388
Author(s):  
JG Chediack ◽  
FD Cid ◽  
SV Fasulo ◽  
E. Caviedes-Vidal
Keyword(s):  
Small Intestine ◽  
Intestinal Transport ◽  
Columba Livia ◽  
Proximal Part ◽  
The Body ◽  
In Vivo Model ◽  
Ecological Studies ◽  
Feral Pigeons ◽  
Chronic Cannulation

We improved a method of chronic duodenal cannulation to study intestinal transport of solutes in an in vivo model (pigeon, Columba livia). A hypoallergenic cannula was inserted into the proximal part of the small intestine of pigeons and used for solution administration. Recovery from surgery was extremely rapid and animals started eating and drinking within a day. After surgery, the body mass of cannulated pigeons was stable, and no adverse effects in the weight could be detected. The method is simple, economical and useful to determine intestinal bioavailability of solutes, for nutritional and ecological studies, in intact animals without influence of anesthesia.

In vivo strain in the humerus of pigeons (Columba livia) during flight

1995 ◽  
Vol 225 (1) ◽  
pp. 61-75 ◽  
Author(s):  
A. A. Biewener ◽  
K. P. Dial
Keyword(s):  
Columba Livia

In vivo pectoralis muscle force-length behavior during level flight in pigeons (Columba livia)

1998 ◽  
Vol 201 (24) ◽  
pp. 3293-3307 ◽  
Author(s):  
A. A. Biewener ◽  
W. R. Corning ◽  
B. W. Tobalske
Keyword(s):  
Power Output ◽  
Muscle Length ◽  
Columba Livia ◽  
Length Change ◽  
Pectoralis Muscle ◽  
Fascicle Length ◽  
Force Development ◽  
Mechanical Power Output ◽  
Muscle Shortening

For the first time, we report in vivo measurements of pectoralis muscle length change obtained using sonomicrometry combined with measurements of its force development via deltopectoral crest strain recordings of a bird in free flight. These measurements allow us to characterize the contractile behavior and mechanical power output of the pectoralis under dynamic conditions of slow level flight in pigeons Columba livia. Our recordings confirm that the pigeon pectoralis generates in vivo work loops that begin with the rapid development of force as the muscle is being stretched or remains nearly isometric near the end of the upstroke. The pectoralis then shortens by a total of 32 % of its resting length during the downstroke,generating an average of 10.33.6 J kg-1 muscle (mean s.d.) of work per cycle for the anterior and posterior sites recorded among the five animals. In contrast to previous kinematic estimates of muscle length change relative to force development, the sonomicrometry measurements of fascicle length change show that force declines during muscle shortening. Simultaneous measurements of fascicle length change at anterior and posterior sites within the same muscle show significant (P<0.001, three of four animals) differences in fractional length (strain) change that averaged 1912 %, despite exhibiting similar work loop shape. Length changes at both anterior and posterior sites were nearly synchronous and had an asymmetrical pattern, with shortening occupying 63 % of the cycle. This nearly 2:1 phase ratio of shortening to lengthening probably favors the ability of the muscle to do work. Mean muscle shortening velocity was 5.381.33 and 4.881.27 lengths s-1 at the anterior and posterior sites respectively. Length excursions of the muscle were more variable at the end of the downstroke (maximum shortening), particularly when the birds landed,compared with highly uniform length excursions at the end of the upstroke(maximum lengthening). When averaged for the muscle as a whole, our in vivo work measurements yield a mass-specific net mechanical power output of 70. 2 W kg-1 for the muscle when the birds flew at 5-6 m s-1, with a wingbeat frequency of 8.7 Hz. This is 38 % greater than the value that we obtained previously for wild-type pigeons, but still 24-50 % less than that predicted by theory.

Sign in / Sign up

Export Citation Format

Share Document