Relative Body Water Research Articles

Use of serum osmolality to identify heart disease stage in dogs and relationship to mathematical chloride correction.

Heart failure-associated hypochloremia can be depletional from diuretics or dilutional from water retention. Serum osmolality reflects water balance but has not been evaluated in dogs with heart disease. To determine if serum osmolality is related to heart disease stage and amount of mathematical correction of serum chloride (Cl- ) concentrations in healthy dogs and dogs with myxomatous mitral valve degeneration (MMVD). Seventy-seven dogs (20 healthy, 25 Stage B MMVD, 32 Stage C/D MMVD). Serum Cl- concentrations were mathematically corrected. Osmolality was calculated (calOsm) and directly measured by freezing point depression (dmOsm) and compared by Bland-Altman analysis. Biochemical variables and osmolality were compared among healthy, Stage B, and Stage C/D dogs. Correlations were explored between osmolality and biochemical variables. Median and range are presented. P < .05 was considered significant. The calOsm was different among groups (P = .003), with Stage B (310 mOsm/kg; 306, 316) and C/D dogs (312 mOsm/kg; 308, 319) having higher calOsm than healthy dogs (305 mOsm/kg; 302, 308). Osmolality methods were moderately correlated (P < .0001, rs = .46) but with proportional bias and poor agreement. The amount of Cl- correction was negatively correlated with calOsm (P < .0001, rs = -.78) and dmOsm (P = .004, rs = -.33). Serum bicarbonate concentration was negatively correlated with Cl- (P < .0001, rs = -.67). Dogs with Stage B and Stage C/D heart disease had higher calOsm than healthy dogs. Osmolality was inversely related to the amount of Cl- correction, which supports its use in assessing relative body water content. Poor agreement between calOsm and dmOsm prevents methodological interchange.

Contribution of Dietary Composition on Water Turnover Rates in Active and Sedentary Men

Body water turnover is a marker of hydration status for measuring total fluid gains and losses over a 24-h period. It can be particularly useful in predicting (and hence, managing) fluid loss in individuals to prevent potential physical, physiological and cognitive declines associated with hypohydration. There is currently limited research investigating the interrelationship of fluid balance, dietary intake and activity level when considering body water turnover. Therefore, this study investigates whether dietary composition and energy expenditure influences body water turnover. In our methodology, thirty-eight males (19 sedentary and 19 physically active) had their total body water and water turnover measured via the isotopic tracer deuterium oxide. Simultaneous tracking of dietary intake (food and fluid) is carried out via dietary recall, and energy expenditure is estimated via accelerometery. Our results show that active participants display a higher energy expenditure, water intake, carbohydrate intake and fibre intake; however, there is no difference in sodium or alcohol intake between the two groups. Relative water turnover in the active group is significantly greater than the sedentary group (Mean Difference (MD) [95% CI] = 17.55 g·kg−1·day−1 [10.90, 24.19]; p = < 0.001; g[95% CI] = 1.70 [0.98, 2.48]). A penalised linear regression provides evidence that the fibre intake (p = 0.033), water intake (p = 0.008), and activity level (p = 0.063) predict participants’ relative body water turnover (R2 = 0.585). In conclusion, water turnover is faster in individuals undertaking regular exercise than in their sedentary counterparts, and is, in part, explained by the intake of water from fluid and high-moisture content foods. The nutrient analysis of the participant diets indicates that increased dietary fibre intake is also positively associated with water turnover rates. The water loss between groups also contributes to the differences observed in water turnover; this is partly related to differences in sweat output during increased energy expenditure from physical activity.

Взаємозв’язок показників фізичної працездатності та компонентного складу тіла у спортсменів-аматорів

Zoya Gorenko, Boris Ocheretko &amp; Antonina KovelskayaPurpose: determine the features of the body component composition and the level of physical performance, as well as the structure of the correlation between these indicators in amateur athletes. Material &amp; Methods: in conditions of the test with physical load with stepwise increasing power in the 71-st physically active person, the reaction of the cardio-respiratory system to physical activity. The body component composition was determined by the bioelectrical impedance method. Result: in amateur athletes, the relative VO2max and power ratings are positively correlated with the relative body water content and have a negative relationship with age, body weight, body mass index, fat content. Oxygen pulse with a high degree of probability positively correlated with body weight, body mass index, metabolic rate, fat-free mass, water content and predictable muscle mass in all body segments. Conclusion: Conducted studies indicate a sufficient level of aerobic capacity, overall performance, the efficiency of the cardiac cycle, the functioning of the О2-transport system and skeletal muscles ability to absorb oxygen from the amateur athletes, and excess fat tissue negatively affects physical performance, overall endurance and achieving high sports results in sports on the endurance.

Hypernatremia in children

Hypernatremia results from a deficit of total body water in relation to the total body's sodium stores. This is caused by two main mechanisms: 1) net water depletion exceeding sodium losses or 2) increased sodium gain exceeding water gain. Net water depletion occurs when increased water loss exceeds sodium loss, either due to extrarenal losses (increased evaporative water losses, hypernatremic dehydration caused by diarrhea) or to renal losses (central and nephrogenic diabetes insipidus, intrinsic renal disease). Insufficient water intake occurs with neonatal hypernatremic dehydration secondary to lactation failure, essential hypernatremia or osmoreceptor dysfunction. Increased sodium gain can be caused by iatrogenic hypernatremia, administration of concentrated infant formula, deliberate abusive water restriction and deliberate or non-accidental salt poisoning. Hypernatremia results in a movement of water across cell membranes from the intracellular to the extracellular space, resulting in cellular dehydration, which, in cells of the central nervous system results in brain shrinkage leading to tearing of cerebral blood vessels and neurological complications. As a protective mechanism, idiogenic osmoles accumulate inside the brain cells to help them retain water intracellularly. However this may lead to cerebral edema during rapid rehydration as these idiogenic osmoles attract water inside the neurons. As the appropriate management of hypernatremia invariably depends on the underlying mechanism and cause, a methodical history taking and clinical examination, with the judicious use of laboratory tests will lead to a precise etiological diagnosis to enable appropriate and timely therapy.

Hypernatremia in children

Hypernatremia results from a deficit of total body water in relation to the total body's sodium stores. This is caused by two main mechanisms: 1) net water depletion exceeding sodium losses or 2) increased sodium gain exceeding water gain. Net water depletion occurs when increased water loss exceeds sodium loss, either due to extrarenal losses (increased evaporative water losses, hypernatremic dehydration caused by diarrhea) or to renal losses (central and nephrogenic diabetes insipidus, intrinsic renal disease). Insufficient water intake occurs with neonatal hypernatremic dehydration secondary to lactation failure, essential hypernatremia or osmoreceptor dysfunction. Increased sodium gain can be caused by iatrogenic hypernatremia, administration of concentrated infant formula, deliberate abusive water restriction and deliberate or non-accidental salt poisoning. Hypernatremia results in a movement of water across cell membranes from the intracellular to the extracellular space, resulting in cellular dehydration, which, in cells of the central nervous system results in brain shrinkage leading to tearing of cerebral blood vessels and neurological complications. As a protective mechanism, idiogenic osmoles accumulate inside the brain cells to help them retain water intracellularly. However this may lead to cerebral edema during rapid rehydration as these idiogenic osmoles attract water inside the neurons. As the appropriate management of hypernatremia invariably depends on the underlying mechanism and cause, a methodical history taking and clinical examination, with the judicious use of laboratory tests will lead to a precise etiological diagnosis to enable appropriate and timely therapy.

Pathogenesis of varroosis at the level of the honey bee (Apis mellifera) colony

The parasitic mite Varroa destructor, in interaction with different viruses, is the main cause of honey bee colony mortality in most parts of the world. Here we studied how effects of individual-level parasitization are reflected by the bee colony as a whole. We measured disease progression in an apiary of 24 hives with differing degree of mite infestation, and investigated its relationship to 28 biometrical, physiological and biochemical indicators. In early summer, when the most heavily infested colonies already showed reduced growth, an elevated ratio of brood to bees, as well as a strong presence of phenoloxidase/prophenoloxidase in hive bees were found to be predictors of the time of colony collapse. One month later, the learning performance of worker bees as well as the activity of glucose oxidase measured from head extracts were significantly linked to the timing of colony collapse. Colonies at the brink of collapse were characterized by reduced weight of winter bees and a strong increase in their relative body water content. Our data confirm the importance of the immune system, known from studies of individually-infested bees, for the pathogenesis of varroosis at colony level. However, they also show that single-bee effects cannot always be extrapolated to the colony as a whole. This fact, together with the prominent role of colony-level factors like the ratio between brood and bees for disease progression, stress the importance of the superorganismal dimension of Varroa research.

Changes in body composition during the winter gestation period in mature beef cows grazing different herbage allowances of native grasslands

The aim of this study was to evaluate the effect of controlling the grazing intensity of native pastures, through the herbage allowances (HA) on body composition (water, protein, and fat) of beef cows of different cow genotype (CG; purebred: Angus and Hereford; PU, and crossbred: reciprocal F1; CR). Mature beef cows (n = 32) were used in a complete randomised block design with a factorial arrangement of HA (2.5 vs 4 kg DM/day; LO vs HI) and CG (PU vs CR). The experiment was conducted during 3 years and at the end of the third year at 150, 210, and 240 ± 10 days of gestation and 190 ± 10 days postpartum body composition was estimated using the urea dilution technique. At 192 ± 10 days postpartum cows were slaughtered and all tissues and organs were weighed and samples were collected for chemical composition analyses. During the winter gestation period, body condition score was greater (P &lt; 0.05) in HI than LO cows and in CR than PU cows. Relative body water (g/kg of empty bodyweight) was greater (P ≤ 0.02) in HI than LO cows and in CR than PU cows, whereas relative body protein did not differ between HI and LO, but tended (P = 0.10) to be greater in CR than PU cows. In contrast, relative body fat tended (P = 0.10) to be greater and gross energy content was greater (P &lt; 0.01) in HI than LO cows, whereas they did not differ between CR and PU cows. Relative body water increased (P &lt; 0.01) from 150 to 210 days of gestation for all cows whereas relative body fat decreased (P &lt; 0.05) and body protein increased (P &lt; 0.05) from 150 to 210 days of gestation in PU but not in CR cows. These results suggest that HI maintained greater body condition score and retained gross energy content when compared with LO cows, and CG affected not only body composition (greater body fat and protein in CR than PU cows) but also composition of mobilised/retained weight during the winter gestation period with a greater protein tissue mobilisation in CR than PU cows.

Commentaries on Viewpoint: Do oxidative and anaerobic energy production in exercising muscle change throughout growth and maturation?

Commentaries on Viewpoint: Do oxidative and anaerobic energy production in exercising muscle change throughout growth and maturation?

Physiology of drought tolerance and cold hardiness of the Mediterranean tiger moth Cymbalophora pudica during summer diapause.

Prepupae of the arctiid moth Cymbalophora pudica spend spring and summer months in a summer diapause (aestivation), the duration of which is photoperiodically controlled. Cold hardiness, drought tolerance and some physiological and biochemical parameters were measured in aestivating prepupae. Large amounts of metabolic reserves, in the form of lipids and glycogen, accumulated prior to aestivation. Glycogen served as the main metabolic fuel for aestivating prepupae. Metabolic rate decreased rapidly after the onset of the inactive prepupal stage and remained low (5–15% of the level in active larva) during aestivation. A spontaneous increase of the respiration rate occurred before pupation. Neither low mol. wt sugars or alcohols (polyols) accumulated nor the haemolymph osmotic pressure changed during aestivation. Drought tolerance of aestivating prepupae was high (no decrease in survival after exposure to r.h.<10% at a temperature of 23°C for a substantial part of diapause) owing to their extensive capacity to stabilize the relative body water content irrespective of the r.h. of surrounding air. Cold hardiness was low (>90% decrease in survival after exposure to −7°C for 24 h). Cold and drought acclimations did not lead to significant changes in the measured physiological and biochemical parameters but cold (not drought) acclimation caused a significant increase in cold hardiness. Neither drought tolerance nor the increase in cold hardiness after cold acclimation appear to be related to presence/accumulation of polyols in aestivating C. pudica prepupae.

Body water relations in two species of gerbil (Tatera indica indica and Meriones hurrianae) of the Indian desert.

The relative body water conservation efficiency of two Indian desert gerbil species, Meriones hurrianae (diurnal/crepuscular) and Tatera indica (nocturnal), has been examined under near-natural conditions in different seasons. A mean urine osmolarity of 3180 mosmol/l (maximum 4645 mosmol/l) in M. hurrianae and a mean value of 5128 mosmol/l (maximum 7547 mosmol/l) in T. indica have been recorded during summer. Urine osmolarity and urea levels indicated that while M. hurrianae remain sufficiently hydrated mainly by virtue of their feeding habit, Tatera indica may depend on the relatively higher concentrating capacity of their kidneys.

Densities and swimbladder development of juvenile American eels, Anguilla rostrata (Lesueur) as related to energetics of migration

Glass eels and elvers of the American eel were negatively buoyant. Those adapted to sea water were more dense (1.072 ± 0.001 g cm−3) than those adapted to fresh water (1.061 ± 0.001 g cm−3). Adaptation to fresh water increased relative body water content, but did not account for the observed decrease in total body density. Histological examination revealed the presence of a potentially functional swimbladder in the glass eels, although this hydrostatic organ did not becomegas‐filled until after freshwater residency had occurred. Calculation of lift as used in the selective tidal transport mechanism suggests that hydrodynamic compensation for horizontal swimming during the estuarine phase of migration is energetically adaptive.

Efficiency of Protein Utilization in Young Rats at Various Levels of Intake

Weanling rats were fed diets containing three different proteins, lactalbumin, casein and soy protein, each fed at levels from zero to over 50% of the diet. Response was measured as total body water in relation to protein consumption. The data confirmed the hypothesis that protein utilization in young rats is constant over an appreciable range of intakes from the maintenance levels to those which allow near maximal growth. Thus it is concluded that the Miller and Payne concept, to the the effect that efficiency of protein utilization for growth declines continuously with increasing dietary protein level, is usually erroneous.

Seasonal Weight and Total Water Content of the Mound‐Building Ant, Formica Exsectoides Forel

The body water content of several insects has been shown to have significance in relation to cold hardiness, starvation and rate of metabolism at different temperatures and humidities. These observations, while interrelated, are neither uniform in their findings nor properly coordinated. For instance, using determinations of freezing point or undercooling point and blood conductivity as criteria for measuring the water content of tissues, Payne ('26 and '28) has shown that oak borers, larvae of Synchroa and Dendroides, and larvae of the Japanese beetle, Popillia japonica, undergo dehydration when subjected to low temperature or low humidity. This condition is associated with increased cold hardiness. Robinson ('28a and '28b) has shown that in proinethlea pupae (Callosamtia pronlethea) and white grubs (Phyllophaga) there is no change in total water content when the animals are subjected to low temperatures. In the case of the pronmethea pupae, however, there is a decrease in the percentage of free water in the tissues during the first two weeks of exposure accompanied by a corresponding increase in the percentage of bound water. He associates this change with increased cold survival. Buxton ('30 and '32) and Mellanby ('32a and '32b) concluded that starving mealworms (Tenebrio molitor), bedbugs (Cimex lectularius) and blood-sucking bugs (Rhodnius prolixus) regulate their rate of metabolism to maintain a constant percentage of water in the body at certain temperatures and humidities to which they are adapted. Both of these conditions, survival of low temperature and regulation of body water in relation to metabolism at different temperatures and humidities, are significant aspects of the problem of adjustment to seasonal temperature as in hibernation. Other investigators, such as Tower ('06), Baumberger ('14), Bodine ('21 and '23) and Fink ('25), have described a decrease in the body water content of various hibernating insects, e.g. the potato beetle, codling moth, and grasshoppers. Bodine ('21 and '23), Fink ('25), Payne ('28) and Kleinman ('34) have reported a decrease in the volume of respiratory exchange and a lowering of the respiratory quotient associated with low temperature during hibernation. In a previous publication (Dreyer, '32) it was shown that the rate of metabolism of the mound-building ant, Formilca ulkei, is greatly altered dur38