Distribution of body fluid and change of blood viscosity in broilers (Gallus domesticus) under high temperature exposure

This study was to observe the distribution of body fluid by measuring blood volume, extracellular and intracellular fluid volumes and total body water under heat exposure, in order to clarify the mechanism of decrease in whole blood viscosity of the heat-exposed broilers. Whole blood viscosity, haematocrit, plasma protein concentration, plasma osmolality and extracellular fluid volume decreased during high temperature exposure, while plasma and blood volumes increased. No significant changes were found in both intracellular fluid volume and total body water between thermoneutral and high temperature exposure. These results indicate the decreased whole blood viscosity is induced by a plasma volume expansion, in which water may come from the interstitial space and alimentary tract, under heat exposure.     

Interleukin-6 deficiency increases blood volume without altering body composition in young mice

This study was carried out to measure blood volume in interleukin-6 (IL-6) deficient and the wild type mice and to relate any differences to concomitant changes in body composition. Young animals (8-20 weeks of age) were used in this study. The red blood cell (RBC) and plasma volumes were measured by isotope-dilution using Cr(51)-labeled erythrocytes and I(131)-labeled human albumin injected simultaneously in each animal. Red blood cells and plasma volumes and hence total measured blood volume were significantly larger in the IL-6-deficient than in either male or female wild type mice. There were no differences in either whole body hematocrit or Fcells ratio. There were no differences in water, fat, protein and mineral content between the genotypes of either gender. Thus, IL-6-deficient mice at young age have a significantly greater blood volume than the wild type mice without concomitant changes in body composition. We suggest that the changes in blood volume may reflect a role for IL-6 in the regulation of the peripheral circulation.     

Erythrocyte volume in man and various animals after the addition of glucose]

The optimal transmission of very diluted blood samples from 11 vertebrate species and man were measured. The red cells of 10 species reduced their volume when glucose or equi-osmotic amounts of sodium chloride were added. Only the erythrocytes of man and monkey (Japanese macaques) did not reduce their volume after addition of glucose or renormalized or overcompensated minor transitory changes. This increase of the volume of human red cells is, however, too low for noticeable viscosity changes of whole blood to be caused, if any. The different response of red cells to glucose makes a simple differentiation between animal and human blood samples possible, provided that primates other than man are excluded.     

Measurement of blood volume in fetal and neonatal sheep using red blood cells labelled with 99m technetium

Blood volume has been measured in fetal and neonatal sheep using red blood cells labelled with 99mTc. The calculated volumes were highly correlated with simultaneous measurements made using the standard 51Cr labelled red cell method, although in absolute terms the 99m Tc method provided volumes which on average exceeded by a small percentage those determined with the 51Cr method. Measurements using the 99mTc method were also made at different ages in fetal and neonatal sheep and, while no correlation could be demonstrated between blood volume and either fetal or neonatal age, neonatal blood volumes were highly correlated with body weight. The 99mTc method is considered to be a reliable technique for measuring perinatal blood volumes in sheep with the short half-life of the isotope offering additional advantages.     

What kind of eye movements will goldfish show in space?

Six goldfish (1 normal, 1 with otoliths removed on both sides, 4 with otoliths removed on one side) were flown in space. The behaviors of the fish were recorded with a video camera on Mission Elapsed Time (MET) Day-00, 02, 05, 08, and 12. On MET Day-00, fish with otoliths removed on one side showed rolling behavior toward the operated side. No rolling behaviors were observed after MET Day-8. Five fish showed backward looping behaviors during the mission. After the space experiment, torsional eye movements and vertical eye movements were examined by body tilting. The experiments showed that the sensitivity of eye movements were low for head up tilting and tilting to operated side.     

Brief report: Body water estimates in normally grown baboon neonates

Water contents of various body water compartments were estimated within nine hours of birth in 11 preterm and eight term baboon (Papio cynocephalus neonates. Estimated water contents of all body compartments (in ml) increased linearly with birthweight (r = 0.52 to 0.90, P ≦ 0.007) and with gestational age (r = 0.46–0.94, P ≤ 0.05). When body water estimates were expressed in proportion to bodyweight (in ml/kg), preterm neonates had significantly larger mean antipyrine space and intracellular water than their term peers. Mean corrected bromide space, interstitial water, plasma volume, blood volume, and red cell volume were similar in preterm and term neonates. Although there are minor differences in body water contents and distribution between baboon and human neonates, baboon data are sufficiently similar to human data to justify using the baboon fetus and neonate as a model for investigations of human development.     

Body height and blood pressure regulation in humans during anti-orthostatic tilting

The hypothesis was tested that the cardiovascular changes during an upper body anti-orthostatic maneuver in humans are more pronounced in tall than in short individuals, because of the larger intravascular hydrostatic pressure gradients. In 34 males and 41 females [20-30 yr, body height (BH) = 147-206 cm], inter-individual multiple linear regression analyses adjusted for gender and body weight were conducted between changes in cardiovascular variables versus BH during tilting of the upper body from vertical to horizontal while keeping the legs horizontal. In all the subjects, tilting induced increases in stroke volume and arterial pulse pressure and a decrease in heart rate, which each correlated significantly with BH. In males (n = 51, BH = 163-206 cm), 24-h ambulatory mean arterial pressure increased significantly with BH (P = 0.004, r = 0.40, α = 0.15 mmHg/cm) so that systolic/diastolic blood pressure increased by 2/2 mmHg per 15 cm increase in BH. There was no significant correlation between mean arterial pressure and BH in females (n = 53, BH = 147-193 cm). In conclusion, a larger BH induces larger cardiovascular changes during anti-orthostatic tilting, and in males 24-h ambulatory mean arterial pressure increases with BH. The lack of a mean arterial pressure to BH correlation in females is probably because of their lower BH and greater variability in blood pressure.     

Direct evidence from parietal extinction of enhancement of visual attention near a visible hand

Brain areas exist that appear to be specialized for the coding of visual space surrounding the body (peripersonal space). In marked contrast to neurons in earlier visual areas, cells have been reported in parietal and frontal lobes that effectively respond only when visual stimuli are located in spatial proximity to a particular body part (for example, face, arm or hand) [1-4]. Despite several single-cell studies, the representation of near visual space has scarcely been investigated in humans. Here we focus on the neuropsychological phenomenon of visual extinction following unilateral brain damage. Patients with this disorder may respond well to a single stimulus in either visual field; however, when two stimuli are presented concurrently, the contralesional stimulus is disregarded or poorly identified. Extinction is commonly thought to reflect a pathological bias in selective vision favoring the ipsilesional side under competitive conditions, as a result of the unilateral brain lesion [5-7]. We examined a parietally damaged patient (D.P.) to determine whether visual extinction is modulated by the position of the hands in peripersonal space. We measured the severity of visual extinction in a task which held constant visual and spatial information about stimuli, while varying the distance between hands and stimuli. We found that selection in the affected visual field was remarkably more efficient when visual events were presented in the space near the contralesional finger than far from it. However, the amelioration of extinction dissolved when hands were covered from view, implying that the effect of hand position was not mediated purely through proprioception. These findings illustrate the importance of the spatial relationship between hand position and object location for the internal construction of visual peripersonal space in humans.     

No gravity-independent gradient of blood flow distribution in dog lung

The existence of a major gravity-independent gradient of blood flow in lungs has recently been described based on single photon emission computed tomography after intravenous injection of radioactively labeled macroaggregates. We wanted to test this hypothesis of a major gravity-independent gradient in lung blood flow in experiments with direct measurement of macroaggregate distribution in the dog lung. In six anesthetized (4 prone spontaneously breathing, 2 mechanically ventilated) dogs we injected 111In-labeled albumin macroaggregates intravenously. We killed the dogs, removed, inflated, and froze the lower lobes. We sliced the lobes 1 cm thick and made gamma camera images of the slices. We then cut three or four slices in each lobe into two or three concentric layers and measured the radioactivity per gram of tissue in a well-type gamma counter. In three of the dogs we also labeled the red cells (99mTc) so that blood volume in each sample could be determined. The gamma camera images were acquired on a 64 X 64 matrix with 4 X 4 mm pixels. On the numeric printouts from the individual slices we made two or three concentric layers and calculated activity per pixel in each layer. Neither by the well counting nor by the pixel analysis of the gamma scans did we detect any gravity-independent distribution of blood flow. With the well counting the distribution was the same whether macroaggregate activity was expressed per gram of tissue or per gram of blood-free tissue. We conclude that by direct measurements no major gravity-independent gradient of pulmonary blood flow can be detected in dog lungs.     

Gravity-independent inequality in pulmonary blood flow in humans

Single-photon emission computerized tomography of the lung with 99mTc-labeled human albumin macroaggregates (99mTc-MAA) was used in six healthy subjects to study the three-dimensional distribution of pulmonary blood flow. 99mTc-MAA was injected while the subjects were resting in the supine position and holding their lung volume at normal end expiration. Tomography was performed on each subject from 120 projections of radioactivity in the lungs acquired with a rotating gamma camera. To minimize lung motion artifacts, the subjects were asked to hold their breath at end expiration during the 10-s duration of data acquisition in each projectional angle. Perfusion images of lung slices (11 mm thick) were reconstructed, and the radioactivity within each slice was expressed per unit lung volume of 3.7 X 3.7 X 11 mm. Perfusion images of a midcoronal slice from each subject manifested a concentric pattern of radioactivity that decreased significantly from the center to the periphery, suggesting that blood flow rate per unit lung volume was up to 10 times larger near the central region. This gradient in activity between the center and the periphery of the coronary slices was gravity independent as the subjects were supine. Images of sagittal slices from the middle of the right lung also manifested a similar pattern of concentric gradient in activity, with the vertical distribution (gravity related) almost comparable with the horizontal distribution (gravity independent). These results indicate that pulmonary blood flow in resting supine humans is spatially stratified with a marked central-to-peripheral gradient in all directions. It appears that zone 4 (reduced blood flow) is not a phenomenon limited to the dependent region of the lung as commonly thought but rather is a manifestation of this spatial distribution whereby blood flow is lowest in all peripheral regions of the lung.     

Difference of arterial pressure regulatory mechanism between awake and anesthetized human subjects

This experiment was conducted to clarify difference of arterial pressure regulatory mechanism between awake and anesthetized human subjects. In 18 subjects who were scheduled for surgical operations, passive tilting test was performed both in awake and anesthetized conditions. Arterial pressure and heart rate were measured during four types of tilting test, i.e., 1. supine-10 degrees head down tilt 2. 10 degrees head down tilt-supine 3. supine-10 degrees head up tilt 4. 10 degrees head up tilt-supine. Relative changes in arterial pressure and heart rate in response to these four tilting tests were compared. After postural changes, all anesthetized subjects showed significant arterial pressure changes followed by restoration of arterial pressure towards control level with opposite changes of heart rate. This initial arterial pressure changes were mainly induced by shift of blood due to gravity and subsequent arterial pressure and heart rate changes were mainly by baro-receptor reflex. On the other hand, awake subjects showed transient increase of heart rate immediately after tilting followed by arterial pressure rise 2 to 3 seconds later in all four tilting tests. However, arterial pressure did not change so remarkably as in anesthetized condition and remained almost constant during tilting test. In awake subjects, their arterial pressure was regulated rapidly and reflex control of arterial pressure was masked. This rapid regulation of arterial pressure may be induced directly by higher central nervous system.     

Body water content and distribution in nonpregnant adult female baboons

Water contents of the various body water compartments were estimated in 16 nonpregnant adult female baboons and compared to human data. Total body water, extracellular water, and plasma volumes were determined by dilution studies. Intracellular water, interstitial water, blood volume, and red cell volume were calculated. The data were compatible with the finding that baboon females probably have less body fat than their human counterparts. Our data establish a basis for longitudinal studies of the changes in body water content and distribution during normal and pathological pregnancies.     

Tissue distribution and physiologically based pharmacokinetics of antisense phosphorothioate oligonucleotide ISIS 1082 in rat

The aim of this study was to develop a whole body physiologically based model of the pharmacokinetics (PBPK) of the phosphorothioate oligonucleotide (PS-ODN) ISIS 1082 in vivo. Rats were administered an intravenous (i.v.) bolus dose of ISIS 1082 (10 mg/kg plus 3H tracer), and arterial blood and tissues were taken at specific times up to 72 hours. Radioactivity was measured in all samples. The parent compound was determined specifically in blood and tissues at 90 minutes and in liver and kidney also at 24 hours, using capillary gel electrophoresis (CGE). A whole body PBPK model was fitted to the combined blood and tissue radioactivity data using nonlinear regression analysis. CGE analysis indicated that the predominant species in plasma and all tissues is ISIS 1082, together with some n-1 and n-2 metabolites. Total radioactivity primarily reflects these species. The whole body model successfully described temporal events in all tissues. However, to adequately model the experimental data, all tissues had to be partitioned into vascular and extravascular spaces to accommodate the relatively slow distribution of ISIS 1082 out of blood because of a permeability rate limitation. ISIS 1082 distributes extensively into tissues, but the relative affinity varies enormously, being highest for kidney and liver and lowest for muscle and brain. A whole body PBPK model with a permeability rate limited tissue distribution was developed that adequately described events in both blood and tissue for an oligonucleotide. This model has the potential not only to characterize the events in individual tissues throughout the body for such compounds but also to scale across animal species, including human.     

Sympathetic alpha-adrenergic regulation of blood flow and volume in hamsters arousing from hibernation

Mammals arousing from hibernation display pronounced regional heterothermy, where the thoracic and head regions warm faster than the abdominal and hindlimb regions. We used laser-Doppler flowmetry to measure peripheral hind foot blood flow during hibernation and arousal and gamma imaging of technetium-labeled albumin to measure whole blood volume distribution in hamsters arousing from hibernation. It was discovered that the hibernating hamster responds to physical but not to sound or hypercapnic stimulation with rapid, 73% reduction of hind foot blood flow. Hind foot blood flow vasoconstriction was maintained from the onset of arousal until late in arousal when rectal temperature was rapidly increased. alpha-Adrenergic blockade early in arousal increased hind foot blood flow by 700%, suggesting that vasoconstriction was mediated by activation of sympathetic tone. Gamma imaging revealed that, by the early phase of arousal from hibernation, the blood volume of the body below the liver is greatly reduced, whereas blood volumes of the thorax and head are much greater than corresponding volumes in anesthetized hamsters. As arousal progresses and cardiac activity increases and regional heterothermy develops, this regional blood volume distribution is largely maintained; however, blood volume slowly decreases in the thoracic region and slowly increases in the shoulder and head regions. The rapid increase in rectal temperature, characteristic of mid- to late- arousal phases, is probably mediated, in part, by reduction of adrenergic tone on abdominal and hindlimb vasculature. Warm blood then moves into the hind body, produces an increase in temperature, blood flow, and blood volume in the hind body and compensatory reductions of blood volume in the neck, head, and thoracic regions.     

Total body haematocrit iron kinetics and erythrocyte life span in pigeons (Columba livia)

1. The mean pigeon erythrocyte life span was found to be 17-25 days by Cr51-labeled erythrocytes and 21 +/- 3.4 days by iron kinetics. 2. Total red blood cell volume has been calculated by Cr51-labeled erythrocytes while total plasma volume was determined both by a dye method and iron kinetic data. From these results total blood volume and total body haematocrit were found to be 0.090 +/- 0.002 ml/g body wt and 36 +/- 4.3%, respectively. 3. Venous haematocrit, haemoglobin concentration, erythrocyte count, mean corpuscular haemoglobin concentration, plasma iron and red blood cell iron have also been measured. 4. A significant difference between total body and venous haematocrit and a short mean red blood cell life span, due to ageing and to random destruction of erythrocytes were shown. 5. The above observations are compared with analogous available data for human beings and their physiological significance is discussed.     

Indices of nutritional state in the western rock lobster, Panulirus longipes1 (Milne Edwards). I. Blood and tissue constituents and water content

Blood protein concentration in the western rock lobster, Panulirus longipes (Milne Edwards), decreased with starvation, but this decrease was due to increase in blood space as solid tissues were metabolized. The total amount of blood protein remained constant during starvation and throughout the moulting cycle, and may be used as a reliable measure of blood volume. No qualitative changes could be detected in blood protein constituents either during starvation or during the moulting cycle.Concentrations of blood non-protein amino acids were also related to blood volume, but there was a small, significant decrease in total amount after 4 weeks starvation.Concentrations of blood non-precipitatable total carbohydrates and blood glucose did not change significantly with starvation, but there were large changes due to the stress of handling.The water content of whole legs, whole abdomen, and abdominal muscle increased significantly with starvation. Protein and non-protein amino-acid concentrations in leg muscle did not change, but protein concentration in abdominal muscle was significantly lowered. Of all solids, those of the digestive gland showed the greatest decrease during starvation.It is concluded that quantitative measurements of blood constituents are meaningless unless related to blood volume. Blood total protein in conjunction with whole leg water content could provide a practical, simple, and non-destructive means of assessing nutritional state in populations of larger rock lobsters if the moulting history were precisely known, but would not be of use for smaller juveniles because of their relatively high moulting frequency. Other constituents (blood amino-acid or abdominal muscle protein concentrations, digestive gland solids, whole abdomen weights) are either not feasible as a field method or involve destruction of the animal. No satisfactory single index of nutritional state, suitable for field use with wild populations, has been found.     

Respiratory changes in parasternal intercostal length

In an attempt to understand the role of the parasternal intercostals in respiration, we measured the changes in length of these muscles during a variety of static and dynamic respiratory maneuvers. Studies were performed on 39 intercostal spaces from 10 anesthetized dogs, and changes in parasternal intercostal length were assessed with pairs of piezoelectric crystals (sonomicrometry). During static maneuvers (passive inflation-deflation, isovolume maneuvers, changes in body position), the parasternal intercostals shortened whenever the rib cage inflated, and they lengthened whenever the rib cage contracted. The changes in parasternal intercostal length, however, were much smaller than the changes in diaphragmatic length, averaging 9.2% of the resting length during inflation from residual volume to total lung capacity and 1.3% during tilting from supine to upright. During quiet breathing the parasternal intercostals always shortened during inspiration and lengthened during expiration. In the intact animals the inspiratory parasternal shortening was close to that seen for the same increase in lung volume during passive inflation and averaged 3.5%. After bilateral phrenicotomy, however, the parasternal intercostal shortening during inspiration markedly increased, whereas tidal volume diminished. These results indicate that 1) the parasternal intercostals in the dog are real agonists (as opposed to fixators) and actively contribute to expand the rib cage and the lung during quiet inspiration, 2) the relationship between lung volume and parasternal length is not unique but depends on the relative contribution of the various inspiratory muscles to tidal volume, and 3) the physiological range of operating length of the parasternal intercostals is considerably smaller than that of the diaphragm.(ABSTRACT TRUNCATED AT 250 WORDS)     

Monitoring changes in body surface temperature associated with treadmill exercise in dogs by use of infrared methodology

The aim of this study was to evaluate the influence of moderate treadmill exercise session on body surface and core temperature in dog measured by means of two infrared instruments. Ten Jack Russell Terrier/Miniature Pinscher mixed-breed dogs were subjected to 15 min of walking, 10 min of trotting and 10 min of gallop. At every step, body surface temperature (T_surface) was measured on seven regions (neck, shoulder, ribs, flank, back, internal thigh and eye) using two different methods, a digital infrared camera (ThermaCam P25) and a non-contact infrared thermometer (Infrared Thermometer THM010-VT001). Rectal temperature (T_rectal) and blood samples were collected before (T0) and after exercise (T3). Blood samples were tested for red blood cell (RBC), hemoglobin concentration (Hb) and hematocrit (Hct). A significant effect of exercise in all body surface regions was found, as measured by both infrared methods. The temperature obtained in the eye and the thigh area were higher with respect to the other studied regions throughout the experimental period (P<0.0001). RBC, Hb, Hct and T_rectal values were higher at T3 (P<0.05). Statistically significant higher temperature values measured by infrared thermometer was found in neck, shoulder, ribs, flank, back regions respect to the values obtained by digital infrared camera (P<0.0001). The results obtained in this study showed that both internal and surface temperatures are influenced by physical exercise probably due to muscle activity and changes in blood flow in dogs. Both infrared instruments used in this study have proven to be useful in detecting surface temperature variations of specific body regions, however factors including type and color of animal hair coat must be taken into account in the interpretation of data obtained by thermography methodology.     

On the edema-preventing effect of the calf muscle pump

During motionless standing an increased hydrostatic pressure leads to increased transcapillary fluid filtration into the interstitial space of the tissues of the lower extremities. The resulting changes in calf volume were measured using a mercury-in-silastic strain gauge. Following a change in body posture from lying to standing or sitting a two-stage change in calf volume was observed. A fast initial filling of the capacitance vessels was followed by a slow but continuous increase in calf volume during motionless standing and sitting with the legs dependent passively. The mean rates of this slow increase were about 0.17%.min-1 during standing and 0.12%.min-1 during sitting, respectively. During cycle ergometer exercise the plethysmographic recordings were highly influenced by movement artifacts. These artifacts, however, were removed from the recordings by low-pass filtering. As a result the slow volume changes, i.e. changes of the extravascular fluid were selected from the recorded signal. Contrary to the increases during standing and sitting the calf volumes of all 30 subjects decreased during cycle ergometer exercise. The mean decrease during 18 min of cycling (2-20 min) was -1.6% at 50 W work load and -1.9% at 100 W, respectively. This difference was statistically significant (p less than or equal to 0.01). The factors which may counteract the development of an interstitial edema, even during quiet standing and sitting, are discussed in detail. During cycling, however, three factors are most likely to contribute to the observed reduction in calf volume: (1) The decrease in venous pressure, which in turn reduces the effective filtration pressure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Tissue blood content in anaesthetised sheep and horses

The blood content of tissue in eight anaesthetized sheep and three anaesthetized horses was measured using chromium labelled autologous red blood cells. 2. Approximately half the total blood volume was found to be distributed within the body tissues and, with the exception of the spleen and fat, the distribution was similar in these two species.