Prey consumption does not restore hydration state but mitigates the energetic costs of water deprivation in an insectivorous lizard.

To cope with limited availability of drinking water in their environment, terrestrial animals have developed numerous behavioral and physiological strategies including maintaining an optimal hydration state through dietary water intake. Recent studies performed in snakes, which are generalist carnivorous reptiles, suggest that the benefits of dietary water intake are negated by hydric costs of digestion. Most lizards are generalist insectivores that can shift their prey types, but firm experimental demonstration of dietary water intake is currently missing in these organisms. Here, we performed an experimental study in the common lizard Zootoca vivipara, a keystone mesopredator from temperate climates exhibiting a great diversity of prey in its mesic habitats, in order to investigate the effects of food consumption and prey type on physiological responses to water deprivation. Our results indicate that common lizards cannot improve their hydration state through prey consumption, irrespective of prey type, suggesting that they are primarily dependent upon drinking water. Yet, high-quality prey consumption reduced the energetic costs of water deprivation, potentially helping lizards to conserve a better body condition during periods of limited water availability. These findings have important implications for understanding the physiological responses of ectotherms to water stress, and highlight the complex interactions between hydration status, energy metabolism and feeding behavior in insectivorous lizards.

Avaliação das dimensões da sede: revisão integrativa / Assessment of the thirst dimension: integrative review

A sede é um sintoma multifatorial e subjetivo cuja mensuração requer múltiplos instrumentos. O objetivo deste estudo foi identificar as dimensões de avaliação da sede e os instrumentos de mensuração utilizados. Incluíram-se artigos publicados entre 2005 a 2015 das bases de dados Lilacs, PubMed e SciELO. A amostra final foi de 18 artigos que evidenciaram as dimensões da sede: intensidade, frequência e desconforto. Também se avaliou a xerostomia e sua intensidade. Essas dimensões foram identificadas por Escalas Visuais Analógicas, Escalas Verbais Numéricas, Escalas de Faces e Escalas Likert, empregadas no Inventário de Sede, Inventário de Xerostomia e Escala de Desconforto da Sede. Avaliou-se a sede principalmente em pacientes dialíticos e internados em unidade de terapia intensiva. Embora a sede seja um sintoma, sua avaliação concentra-se sobretudo na intensidade e é realizada em populações específicas.

Thirst is a multifactorial and subjective symptom that request multiple measuring instruments. The objective of this study was to identify the assessment dimensions of thirst and the measurement tools used. We included studies published between 2005 and 2015 from the databases Lilacs, PubMed and SciELO. Eighteen articles composed the final sample that showed thirst dimensions: intensity, frequency, and discomfort. We also assessed the xerostomia and its intensity. These dimensions were identified by Visual Analogic Scales, Verbal Numeric Scales, Face's Scales and Likert-type Scales, used in the Thirst Inventory, Xerostomia Inventory, and Thirst Discomfort Scale. We assessed thirst especially in dialytic patients and the ones admitted to the intensive care unit. Although thirst is a symptom, in general, its assessment concentrates in its intensity, and it is conducted in specific populations

Automated assessment of pain in rats using a voluntarily accessed static weight-bearing test.

UNLABELLED: The weight-bearing test is one method to assess pain in rodent animal models; however, the acceptance of this convenient method is limited by the low throughput data acquisition and necessity of confining the rodents to a small chamber. NEW METHODS: We developed novel data acquisition hardware and software, data analysis software, and a conditioning protocol for an automated high throughput static weight-bearing assessment of pain. With this device, the rats voluntarily enter the weighing chamber, precluding the necessity to restrain the animals and thereby removing the potential stress-induced confounds as well as operator selection bias during data collection. We name this device the Voluntarily Accessed Static Incapacitance Chamber (VASIC). RESULTS: Control rats subjected to the VASIC device provided hundreds of weight-bearing data points in a single behavioral assay. Chronic constriction injury (CCI) surgery and paw pad injection of complete Freund's adjuvant (CFA) or carrageenan in rats generated hundreds of weight-bearing data during a 30 minute recording session. Rats subjected to CCI, CFA, or carrageenan demonstrated the expected bias in weight distribution favoring the un-operated leg, and the analgesic effect of i.p. morphine was demonstrated. In comparison with existing methods, brief water restriction encouraged the rats to enter the weighing chamber to access water, and an infrared detector confirmed the rat position with feet properly positioned on the footplates, triggering data collection. This allowed hands-off measurement of weight distribution data reducing operator selection bias. CONCLUSION: The VASIC device should enhance the hands-free parallel collection of unbiased weight-bearing data in a high throughput manner, allowing further testing of this behavioral measure as an effective assessment of pain in rodents.

Assessment of growth performance, immune responses, serum metabolites, and prevalence of leg weakness in broiler chicks submitted to early-age water restriction.

The objective of this study was to evaluate the effects of two methods of early-age water restriction on performance, some immune responses, serum metabolites, and prevalence of leg weakness in broiler chicks. One-hundred-eighty-seven-day-old chicks (Ross 308) were allocated to three treatments with four replicates based on a completely randomized design. Treatments included the control group, where birds had free access to water, and water-restricted groups, where access to water was limited to three 2-h periods (WRT1) or a 12-h period (WRT2) per day from days 7 to 17. Chicks in the control group were significantly heavier (P < 0.05) at 17 and 46 days of age compared to the restricted birds. In the WRT2 group, feed intake decreased significantly over the 17- to 28-day period while feed conversion ratio was poorer during water restriction (P < 0.05). Antibody titers against Newcastle and SRBC were higher (P < 0.05) for chicks with ad libitum access to water. Birds in the restricted groups exhibited a higher heterophil to lymphocyte ratio compared to the control group (P < 0.05). The treatments had no significant impact on serum metabolites including protein, triglyceride, total cholesterol, high-density lipoprotein and low-density lipoprotein cholesterols, calcium, and phosphorus concentrations. Walking ability, tibial dyschondroplasia, foot pad, hock burn, and valgus/varus angulation were not significantly influenced by water restriction. In conclusion, the current results indicate that early-age water restriction negatively influenced productive traits and immunological responses of broiler chicks and failed to have any favorable impacts on leg health.

The assessment and treatment of water imbalance in patients with psychosis.

Polydipsia and episodic life-threatening water intoxication remain important clinical problems for a significant portion of persons with schizophrenia. The disorders are associated with increased morbidity and mortality from a number of causes. With a basic understanding of the pathophysiology, one can easily diagnose and assess the clinical conditions. We review here the scope and pathophysiology of disordered water imbalance, including both primary and secondary polydipsia and hyponatremia. Reversible factors and possible interventions are reviewed. Treatment options for preventing water intoxication have expanded from discontinuation of offending agents, targeted fluid restriction, and clozapine therapy to the addition of oral vasopressin antagonists. The latter, however, are extremely potent and must be carefully monitored.

Vasopressinergic network abnormalities potentiate conditioned anxious state of rats subjected to maternal hyperthyroidism.

We have previously reported that a mild maternal hyperthyroidism in rats impairs stress coping of adult offspring. To assess anxiogenesis in this rat model of stress over-reactivity, we used two behavioural tests for unconditional and conditional anxious states: elevated plus maze test (EPM) and Vogel conflict test (VCT). In the latter one, arginine vasopressin (AVP) release was enhanced due to osmotic stress. With the EPM test no differences were observed between maternal hyperthyroid rats (MH) and controls. However, with the VCT, the MH showed increased anxiety-like behaviour. This behavioural difference was abolished by diazepam. Plasma AVP concentration curve as a function of water deprivation (WD) time showed a marked increase, reaching its maximal levels within half the time of controls and another significant difference after VCT. A general increase in Fos expression in hypothalamic supraoptic and paraventricular nuclei (PVN) was observed during WD and after VCT. There was also a significant increase of AVP immunoreactivity in anterior hypothalamic area. A large number of Herring bodies were observed in the AVP containing fibres of MH hypothalamic-neurohypophysial system. Numerous reciprocal synaptic connections between AVP and corticotropin releasing factor containing neurons in MH ventromedial PVN were observed by electron microscopy. These results suggest that a mild maternal hyperthyroidism could induce an aberrant organization in offspring's hypothalamic stress related regions which could mediate the enhanced anxiety seen in this animal model.

Echocardiographic assessment of hemodynamic changes produced by two methods of inducing fluid deficit in dogs.

BACKGROUND: Hydration status is important to the cardiovascular system because of its effects on preload. Decreased preload can alter echocardiographic measurements of systolic and diastolic function, potentially confounding interpretation of results. HYPOTHESIS/OBJECTIVES: Mild fluid deficits are associated with measurable echocardiographic changes that are validated by physical and biochemical markers of decreased intravascular volume. ANIMALS: Twenty-five healthy staff/student-owned dogs with no evidence of cardiac or renal disease. METHODS: Prospective, interventional laboratory study. Dogs were randomly assigned to water deprivation (WD) alone for 8 hours (n = 13) or to furosemide treatment (FTx, 2.5mg/kg IV) followed by WD for 8 hours (n = 12). Echocardiograms, biochemical sampling, and physical parameters were measured at baseline, and after 4 and 8 hours. RESULTS: Both protocols induced fluid deficit as indicated by significant (P < .00001) decreases in weight at 4 hours (WD, 1.1%; FTx, 3.7%) and 8 hours (WD, 2.7%; FTx, 4.5%). Furosemide significantly decreased left ventricular end-diastolic volume (54.3 +/- 19.3-42.1 +/- 17.3 mL, P < .0001), cardiac index (4.2 +/- 1.1-2.9 +/- 0.9 L/min/M2, P < .0001), and mitral valve E wave velocity (0.79 +/- 0.2-0.66 +/- 0.2 m/s, P = .0004). These changes were accompanied by significant increases in blood urea nitrogen concentration (13.8 +/- 2.6-14.8 +/- 2.7 mg/dL, P = .04), vasopressin concentration (1.4 +/- 1.2-3.3 +/- 1.9 pg/mL, P = .045), and PCV (49.8 +/- 4.5-53.2 +/- 6.5%, P = .006). Effects of water deprivation alone were similar, but less pronounced. CONCLUSIONS AND CLINICAL IMPORTANCE: Mild fluid deficits have measurable hemodynamic effects in dogs. Hydration status should be considered when evaluating cardiac function by echocardiogram.

Promoting childbirth companions in South Africa: a randomised pilot study.

BACKGROUND: Most women delivering in South African State Maternity Hospitals do not have a childbirth companion; in addition, the quality of care could be better, and at times women are treated inhumanely. We piloted a multi-faceted intervention to encourage uptake of childbirth companions in state hospitals, and hypothesised that lay carers would improve the behaviour of health professionals. METHODS: We conducted a pilot randomised controlled trial of an intervention to promote childbirth companions in hospital deliveries. We promoted evidence-based information for maternity staff at 10 hospitals through access to the World Health Organization Reproductive Health Library (RHL), computer hardware and training to all ten hospitals. We surveyed 200 women at each site, measuring companionship, and indicators of good obstetric practice and humanity of care. Five hospitals were then randomly allocated to receive an educational intervention to promote childbirth companions, and we surveyed all hospitals again at eight months through a repeat survey of postnatal women. Changes in median values between intervention and control hospitals were examined. RESULTS: At baseline, the majority of hospitals did not allow a companion, or access to food or fluids. A third of women were given an episiotomy. Some women were shouted at (17.7%, N = 2085), and a few reported being slapped or struck (4.3%, N = 2080). Despite an initial positive response from staff to the childbirth companion intervention, we detected no difference between intervention and control hospitals in relation to whether a companion was allowed by nursing staff, good obstetric practice or humanity of care. CONCLUSION: The quality and humanity of care in these state hospitals needs to improve. Introducing childbirth companions was more difficult than we anticipated, particularly in under-resourced health care systems with frequent staff changes. We were unable to determine whether the presence of a lay carer impacted on the humanity of care provided by health professionals. TRIAL REGISTRATION: Current Controlled Trials ISRCTN33728802.

Physiological adjustments of sand gazelles (Gazella subgutturosa) to a boom-or-bust economy: standard fasting metabolic rate, total evaporative water loss, and changes in the sizes of organs during food and water restriction.

To test the hypothesis that desert ungulates adjust their physiology in response to long-term food and water restriction, we established three groups of sand gazelles (Gazella subgutturosa): one that was provided food and water (n = 6; CTRL) ad lib. for 4 mo, one that received ad lib. food and water for the same period but was deprived of food and water for the last 4.5 d (n = 6; EXPT(1)), and one that was exposed to 4 mo of progressive food and water restriction, an experimental regime designed to mimic conditions in a natural desert setting (n = 6; EXPT(2)). At the end of the 4-mo experiment, we measured standard fasting metabolic rate (SFMR) and total evaporative water loss (TEWL) of all sand gazelles and determined lean dry mass of organs of gazelles in CTRL and EXPT(2). Gazelles in CTRL had a mean SFMR of 2,524 +/- 194 kJ d(-1), whereas gazelles in EXPT(1) and EXPT(2) had SFMRs of 2,101+/- 232 and 1,365 +/- 182 kJ d(-1), respectively, values that differed significantly when we controlled for differences in body mass. Gazelles had TEWLs of 151.1 +/- 18.2, 138.5 +/- 17.53, and 98.4 +/- 27.2 g H(2)O d(-1) in CTRL, EXPT(1), and EXPT(2), respectively. For the latter group, mass-independent TEWL was 27.1% of the value for CTRL. We found that normally hydrated sand gazelles had a low mass-adjusted TEWL compared with other arid-zone ungulates: 13.6 g H(2)O kg(-0.898) d(-1), only 17.1% of allometric predictions, the lowest ever measured in an arid-zone ungulate. After 4 mo of progressive food and water restriction, dry lean mass of liver, heart, and muscle of gazelles in EXPT(2) was significantly less than that of these same organs in CTRL, even when we controlled for body mass decrease. Decreases in the dry lean mass of liver explained 70.4% of the variance of SFMR in food- and water-restricted gazelles. As oxygen demands decreased because of reduced organ sizes, gazelles lost less evaporative water, probably because of a decreased respiratory water loss.

A cost of long-term memory in Drosophila.

Two distinct forms of consolidated associative memory are known in Drosophila: long-term memory and so-called anesthesia-resistant memory. Long-term memory is more stable, but unlike anesthesia-resistant memory, its formation requires protein synthesis. We show that flies induced to form long-term memory become more susceptible to extreme stress (such as desiccation). In contrast, induction of anesthesia-resistant memory had no detectable effect on desiccation resistance. This finding may help to explain why evolution has maintained anesthesia-resistant memory as another form of consolidated memory, distinct from long-term memory.

Toxicology studies of a chemical mixture of 25 groundwater contaminants: hepatic and renal assessment, response to carbon tetrachloride challenge, and influence of treatment-induced water restriction.

Because groundwater contamination is an important environmental concern, we examined the hepatic and renal effects of repeated exposure to a mixture of 25 chemicals frequently found in groundwater near hazardous-waste disposal sites and the effect of such exposure on carbon tetrachloride (CCI4) toxicity. Adult male F-344 rats received ad libitum deionized water and feed (Ad Lib Water) or ad libitum 10% MIX (referring to 10% of a technically achievable stock mixture) and feed for 14 d. Because exposure to the 25-chemical mixture via the drinking water resulted in decreased water and feed consumption, restricted deionized water and feed controls (Restricted Water) were included. On d 14, rats were gavaged with 0, 0.0375, 0.05, 0.075 or 0.15 ml CCl4/kg, and hepatic and renal toxicity assessed 24 h later. Little or no hepatic and renal toxicity was observed in rats exposed to 10% MIX alone. No hepatic or renal lesions occurred that could be attributed to 10% MIX alone. Slight but statistically significant alterations, of uncertain biological significance, resulted from the water treatments: 10% MIX increased alanine aminotransferase, urea nitrogen (BUN), and BUN/creatinine ratio; Restricted Water increased 5'-nucleotidase and decreased alkaline phosphatase. Relative kidney weight was increased by both 10% MIX and Restricted Water. CCI4 resulted in significant dosage-dependent hepatotoxicity in all three water treatment groups but had little or no effect on renal indicators of toxicity. Relative to Ad Lib Water, significantly greater hepatotoxicity occurred in both 10% MIX and Restricted Water rats. The response to CCI4 in the Restricted Water rats was similar to that of 10% MIX rats, indicating that a substantial portion of the effect of 10% MIX on CCI4 hepatotoxicity is due to decreased water and feed intake.

[The assessment of the action of pharmacological agents based on a new computer program for analysing animal operant behavior]. / Otsenka deistviia farmakologicheskikh sredstv na osnove novoi komp'iuternoi programmy dlia analiza operantnogo povedeniia zhivotnykh.

The new programme is developed for the experimental automatization and analysis of animal operant behavior in Skinner's box (Lafayette Instrument Co., USA) by means of the Apple 2e computer (USA). The fundamental of the programme is the division of the training procedure into different functional intervals. Operant behavior of rats is determined by diverse schedules of food and water reinforcement and electric shock. Rats were trained to response on schedules FR 20, FI 1, drug discrimination. Phenazepam (2 mg/kg) markedly decreases the number of responses on schedule FR 20. Phenazepam is a discriminable stimulus. The experimental results make it possible to use the programme for modelling various forms of operant behavior and analysing pharmacological properties of the well-known and new drugs.

Comparative water economy of sympatric rodents in a Chilean semi-arid habitat.

1. Water requirements, water balance components and dependence on exogenous water were estimated in four species of sympatric rodents inhabiting a Chilean semi-arid region. 2. A significant increase in free water drinking was observed in all rodents when the diet composition was changed from 14 to 20% protein. 3. Under water balance conditions the cricetid species (Phyllotis darwini, Oryzomys longicaudatus and Akodon olivaceus) showed 1.66 to 1.88 times the weight-specific daily water gain of Octodon degus. 4. In the three cricetid rodents, evaporation was the largest water loss component (2/3 to 3/4 of total loss), while in O. degus evaporative water loss amounted to only 38% of the total. 5. Survival time during water deprivation ranged from 13.4 days in O. degus to only 4 days in O. longicaudatus. 6. All water variables combined indicate that water dependence of O. longicaudatus greater than P. darwini greater than A. olivaceus greater than O. degus.

Acute water shortage and health problems in Haiti.

During a severe drought Port-au-Prince, Haiti, lost hydroelectric power for 10 weeks. This led to water shortages in areas of the city dependent on water supplied from electrically driven pumps. In a study of the impact of water restriction on disease, 400 families were randomly selected from two urban areas differentially affected by the water shortage. Disease in children was found to be related to quantity of water used, socioeconomic status, employment of head of household, and family size. The methods used in this study are recommended for the investigation of the relationship between water quantity and health.

Assessment of urine-concentrating ability in man: effect of fludrocortisone and urea in enhancing response to vasopressin.

1. Healthy subjects, given a long-acting preparation of vasopressin intramuscularly, excreted a significantly less concentrated urine than when subjected to fluid deprivation for 28 h. 2. When fludrocortisone, a potent mineralocorticoid, was given in addition to vasopressin the urine was not significantly less concentrated than after fluid deprivation. 3. Oral urea-loading also enhanced the urine-concentrating power of vasopressin but its effect was less marked than that of fludrocortisone. Oral urea did not increase further the urine concentration achieved by combined fludrocortisone and vasopressin. 4. Renal concentrating power was assessed in fourteen patients with renal disease and impaired concentrating ability. Fludrocortisone significantly enhanced the urine concentration achieved by vasopressin alone and the resultant urine was not significantly less concentrated than that achieved by fluid deprivation. 5. The action of fludrocortisone in enhancing the urine-concentrating effect of vasopressin is similar to that of aldosterone and is probably due to the increased sequestration of solute in the renal medulla, caused by increased reabsorption of sodium chloride in the ascending limb of the loop of Henle. 6. In the clinical assessment of renal concentrating power, the combined use of fludrocortisone and vasopressin has potential advantages over established methods.