Ecology of parasitism of nestling American kestrels by Carnus hemapterus (Diptera: Carnidae)

1997 ◽  
Vol 75 (12) ◽  
pp. 2021-2026 ◽  
Author(s):  
Russell D. Dawson ◽  
Gary R. Bortolotti

Little is known about the basic biology of Carnus hemapterus (Diptera: Carnidae), a haematophagous parasite of nestling birds. We therefore explored the patterns of C. hemapterus infestations by repeatedly examining American kestrel (Falco sparverius) nestlings from 50 nests in north-central Saskatchewan. Most infestations occurred before chicks were 12 days old and were more frequent early in the breeding season. Nestlings from larger broods had higher prevalences of C. hemapterus, but we did not detect differences in intensity of infestations between broods of different sizes. Within broods up to 5 days old, the heaviest nestlings were preferentially infested by C. hemapterus. Although evidence suggests that ectoparasite infestations are harmful to hosts, we did not detect any mortality attributable to C. hemapterus. Similarly, we did not observe negative effects of C. hemapterus infestations on nestling mass, length of the tenth primary flight feather, haematocrit, or total plasma protein concentration at 24 days old.

1997 ◽  
Vol 273 (1) ◽  
pp. G227-G238 ◽  
Author(s):  
P. Ott ◽  
R. A. Weisiger

We used a novel parameter-free approach to study the role of protein binding in the hepatic clearance of indocyanine green (ICG) from reconstituted pig blood by perfused rat liver. Either perfusate total plasma protein concentration or hematocrit was changed. By analyzing protein concentration ratios or plasma volume ratios relative to ratios of intrinsic hepatic clearance of ICG (K), it was possible to evaluate current models of hepatic uptake of protein-bound ligands without precise knowledge of some of the model parameters. A four-fold increase in the total plasma protein concentration produced only a 36% decrease in K. This was substantially less than predicted by the traditional model, where K is proportional to the free concentration of ligand. Because an unstirred water layer effect could not by itself account for the observations, the effects of binding disequilibrium in the sinusoids or uptake directly from the bound pool had to be considered. To discriminate, hematocrit was increased from 15% to 29%, causing a 20% decrease in the sinusoidal plasma volume. A significant reduction in K strongly suggested a sinusoidal binding disequilibrium effect. The dissociation rate constant predicted by this model was confirmed by in vitro measurement, further supporting this interpretation. The simple experimental design and its parameter-free evaluation provide a new tool for investigating the hepatic uptake of protein-bound ligands.


1993 ◽  
Vol 75 (2) ◽  
pp. 1002-1008 ◽  
Author(s):  
J. R. Naylor ◽  
W. M. Bayly ◽  
H. C. Schott ◽  
P. D. Gollnick ◽  
D. R. Hodgson

The effects of dehydration and 40 min of exercise at approximately 40% of maximal O2 consumption on plasma volume (PV) and blood volume (BV) were studied in six horses. Horses were exercised while euhydrated (C); 4 h after administration of furosemide (1.0 mg/kg i.v.; FDH), which induced isotonic dehydration; and after 30 h without water (DDH), which caused hypertonic dehydration. Dehydration resulted in decreases of 6.3 and 9.9% for PV and BV, respectively, with FDH and 10.7 and 8.5%, respectively, with DDH. During exercise in C, PV and BV increased by 12.7 and 20.0%, respectively; during exercise with FDH, they increased by 11.7 and 26.1%, respectively; and during exercise with DDH, PV decreased by 1.3% from predehydration values, while BV increased by 18.7%. Hematocrit and total plasma protein concentration rose to higher values throughout exercise in FDH and DDH than in C; plasma [Na+] was higher in DDH than in FDH and C, [Cl-] was higher in DDH and lower in FDH than in C, and [K+] was lower in FDH and DDH than in C through exercise and recovery. From these results, we conclude that increases in PV and BV are normal features of low-intensity exercise in the horse. The increases in BV not only augment O2 carriage but also help maintain circulating volume. These increases can be modified by preexercise dehydration, the nature of which affects the extent of modification.


1932 ◽  
Vol 55 (5) ◽  
pp. 683-693 ◽  
Author(s):  
C. W. Barnett ◽  
R. B. Jones ◽  
R. B. Cohn

1. Experiments on five dogs are described consisting in the daily removal of blood plasma in amount from 25 to 100 cc. the red cells being returned to the circulation in Locke's solution. In no case was there a significant drop in plasma protein concentration. 2. A gravimetric method for the determination of total plasma protein is described. 3. A case is reported of cirrhosis of the liver in which over 10 gm. of protein daily was lost in the ascitic fluid during a period of 7 months without any lowering of plasma protein concentration. 4. The constancy of the plasma protein level and the adequacy of the mechanism of regeneration is pointed out.


1995 ◽  
Vol 6 (2) ◽  
pp. 214-219 ◽  
Author(s):  
J K Leypoldt ◽  
A K Cheung ◽  
R R Steuer ◽  
D H Harris ◽  
J M Conis

Dialysis-induced hypovolemia occurs because the rate of extracorporeal ultrafiltration exceeds the rate of refilling of the blood compartment. The purpose of this study was to evaluate a method for calculating circulating blood volume (BV) during hemodialysis (HD) from changes in hematocrit (Hct) shortly (2 to 10 min) before and after ultrafiltration (UF) was abruptly stopped. Hct was monitored continuously during 93 HD treatment sessions in 16 patients by an optical technique and at selected times by centrifugation of blood samples. Total plasma protein and albumin concentrations were also measured at selected times. Continuously monitored Hct correlated with Hct determined by centrifugation (R = 0.89, N = 579). Relative changes in BV determined by continuously monitored Hct were not different from those determined by total plasma protein concentration (P = 0.05; N = 273). Calculated BV at the start of dialysis (4.1 +/- 1.3 L) was not different (P = 0.18, N = 12) from that derived anthropometrically from the patient's dry weight (4.6 +/- 0.8 L), and calculated BV when UF was stopped was 3.2 +/- 0.5 L (46 +/- 7 ml/kg body wt). These latter estimates of BV are consistent with those determined previously by dilution techniques in HD patients. It was concluded that (1) relative changes in BV assessed by continuously monitored Hct were unbiased and (2) BV can be determined noninvasively during HD by continuously monitoring Hct and temporarily stopping UF.


2021 ◽  
Vol 99 (Supplement_2) ◽  
pp. 42-42
Author(s):  
Yaser M Ahmed ◽  
Hamid Ismail ◽  
Djaafar M Rehrah ◽  
Mulumebet Worku

Abstract Gastrointestinal nematodes and other pathogens pose a major problem for goat production by reducing animal performance and welfare. Plants such as Acacia Senegal are useful as dietary sources for natural prophylaxis. Gum Arabica (GA) from A. Sengal has antimicrobial, anti-inflammatory properties that need to be explored in goats. The objective of this study was to investigate the possible immunomodulatory effect of a water extract of GA in goat blood. Clinically healthy Boer and Spanish goats from the NCA&T Small ruminant unit were used. Goats were assigned randomly to two groups of ten (n = 20). Goats of one group were drenched daily with 10 mL of GA (treatment I) extract for 6 weeks. The second (control) group of goats received sterile water (treatment II). Blood was collected from the jugular vein in tubes containing acid-citrate-dextrose anticoagulant. Plasma was separated and the concentration of total protein was determined using Pierce BCA kit (Thermo Scientific Pierce, Rockford, IL). The white blood cell differential count was assessed on Wrights smeared stains. Data were analyzed using PROC GLM in SAS 9.4 (P < 0.05). Treatment with GA modulated total plasma protein concentration and the differential white blood cell counts. Treatment increased total plasma protein concentration and % lymphocytes, it decreased % neutrophils. Immunomodulation by GA may be advantageous in promoting health and wellness in goats. Further studies on the mechanism of action are warranted.


1975 ◽  
Vol 49 (6) ◽  
pp. 629-632 ◽  
Author(s):  
M. W. Johns ◽  
J. P. Masterton ◽  
J. E. Paddle-Ledinek ◽  
Y. C. Patel ◽  
D. Winikoff ◽  
...  

1. The total serum thyroxine, tri-iodothyronine resin uptake, total plasma protein concentration and the free thyroxine index (FTI) were determined repeatedly, at 07.15, 13.00 and 22.30 hours over 4 days, in six healthy young men. 2. There was a significant diurnal variation in the total serum thyroxine concentration but this reflected changes in the binding capacity of serum proteins and in the total plasma protein concentration which could be explained by changes of posture. The FTI, and presumably therefore the free thyroxine concentration, varied very little with the time of day. 3. The FTI varied significantly from day to day in three of the six subjects, presumably as a result of changes in thyroxine secretion because the serum binding capacity did not vary. 4. The subjects' sleep at night was assessed by electro-encephalogram. On days when the FTI was highest for a particular subject his sleep was more fragmented by spontaneous awakenings, the amount of rapid-eye-movement sleep was reduced and that of delta-wave sleep was increased, implying that variations in thyroid function over a period of a few days in healthy subjects can be of physiological significance. The cause of these variations is uncertain.


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