Water-loss dehydration and aging

This review defines water-loss and salt-loss dehydration. For older people serum osmolality appears the most appropriate gold standard for diagnosis of water-loss dehydration, but clear signs of early dehydration have not been developed. In older adults, lower muscle mass, reduced kidney function, physical and cognitive disabilities, blunted thirst, and polypharmacy all increase dehydration risk. Cross-sectional studies suggest a water-loss dehydration prevalence of 20-30% in this population. Water-loss dehydration is associated with higher mortality, morbidity and disability in older people, but evidence is still needed that this relationship is causal. There are a variety of ways we may be able to help older people reduce their risk of dehydration by recognising that they are not drinking enough, and being helped to drink more. Strategies to increase fluid intake in residential care homes include identifying and overcoming individual and institutional barriers to drinking, such as being worried about not reaching the toilet in time, physical inability to make or to reach drinks, and reduced social drinking and drinking pleasure. Research needs are discussed, some of which will be addressed by the FP7-funded NU-AGE (New dietary strategies addressing the specific needs of elderly population for a healthy ageing in Europe) trial

Increasing fluid intake and reducing dehydration risk in older people living in long-term care: a systematic review

Objective: To assess the efficacy of interventions and environmental factors on increasing fluid intake or reducing dehydration risk in older people living in long-term care facilities. Design: Systematic review of intervention and observational studies. Data Sources: Thirteen electronic databases were searched from inception until September 2013 in all languages. References of included papers and reviews were checked. Eligibility criteria: Intervention and observational studies investigating modifiable factors to increase fluid intake and/or reduce dehydration risk in older people (≥65 years) living in long-term care facilities who could drink orally. Review methods: Two reviewers independently screened, selected, abstracted data and assessed risk of bias from included studies, narrative synthesis was performed. Results: 4328 titles and abstracts were identified, 325 full-text papers obtained and 23 included in the review. Nineteen intervention and 4 observational studies from 7 countries investigated factors at resident, institutional or policy level. Overall the studies were at high risk of bias due to selection and attrition bias and lack of valid outcome measures of fluid intake and dehydration assessment. Reported findings from six of the nine intervention studies investigating the effect of multi-component strategies on fluid intake or dehydration described a positive effect. Components included greater choice and availability of beverages, increased staff awareness, increased staff assistance with drinking and toileting. Implementation of the US Resident Assessment Instrument reduced dehydration prevalence from 3% to 1%, p=0.01. Two smaller studies reported positive effects, one on fluid intake in 9 men with Alzheimer's Disease using high-contrast red cups, the other involved supplementing 13 mildly dehydrated residents with oral hydration solution over 5 days to reduce dehydration. Modifications to the dining environment, advice to residents, presentation of beverages and mode of delivery (straw vs beaker; pre-thickened drinks vs those thickened at the bedside) were inconclusive. Two large observational studies with good internal validity investigated effects of ownership; in Canada, for-profit ownership was associated with increased hospital admissions for dehydration; no difference was seen in dehydration prevalence between US for-profit and not-for-profit homes, although chain facilities were associated with lower odds of dehydration. This US study did not suggest any effect of staffing levels on dehydration prevalence. Conclusions: A wide range of interventions and exposures were identified, but the efficacy of many strategies remains unproven due to the high risk of bias present in many studies. Reducing dehydration prevalence in long-term care facilities is likely to require multiple strategies involving policymakers, management and care staff, but these require further investigation using more robust study methodologies. Systematic review registration: The review protocol was registered with the International Prospective Register of Systematic Reviews (http://www.crd.york.ac.uk/PROSPERO/display_record.asp? ID=CRD42012003100)

Diagnostic accuracy of calculated serum osmolarity to predict dehydration in older people: adding value to pathology lab reports

Objectives: To assess which osmolarity equation best predicts directly measured serum/plasma osmolality and whether its use could add value to routine blood test results through screening for dehydration in older people. Design: Diagnostic accuracy study Participants: Older people (≥65 years) in 5 cohorts: Dietary Strategies for Healthy Ageing in Europe (NU-AGE, living in the community), Dehydration Recognition In our Elders (DRIE, living in residential care), Fortes (admitted to acute medical care), Sjöstrand (emergency room) or Pfortmueller cohorts (hospitalised with liver cirrhosis). Reference standard for hydration status: Directly measured serum/plasma osmolality: current dehydration (serum osmolality >300mOsm/kg), impending/current dehydration (≥295mOsm/kg). Index tests: 39 osmolarity equations calculated using serum indices from the same blood draw as directly measured osmolality. Results: Across five cohorts 595 older people were included, of whom 19% were dehydrated (directly measured osmolality >300mOsm/kg). Of 39 osmolarity equations, five showed reasonable agreement with directly measured osmolality and three had good predictive accuracy in subgroups with diabetes and poor renal function. Two equations were characterized by narrower limits of agreement, low levels of differential bias and good diagnostic accuracy in ROC plots (areas under the curve >0.8). The best equation was osmolarity =1.86 × (Na+ + K+) + 1.15 × glucose + urea + 14 (all measured in mmol/L). It appeared useful in people aged ≥65 years with and without diabetes, poor renal function, dehydration, in men and women, with a range of ages, health, cognitive and functional status. Conclusions: Some commonly used osmolarity equations work poorly, and should not be used. Given costs and prevalence of dehydration in older people we suggest use of the best formula by pathology laboratories using a cutpoint of 295mOsm/L (sensitivity 85%, specificity 59%), to report dehydration risk opportunistically when serum glucose, urea and electrolytes are measured for other reasons in older adults

The impact of fire suppression tasks on firefighter hydration: A critical review with consideration of the utility of reported hydration measures

BACKGROUND: Firefighting is a highly stressful occupation with unique physical challenges, apparel and environments that increase the potential for dehydration. Dehydration leaves the firefighter at risk of harm to their health, safety and performance. The purpose of this review was to critically analyse the current literature investigating the impact of fighting ‘live’ fires on firefighter hydration. METHODS: A systematic search was performed of four electronic databases for relevant published studies investigating the impact of live fire suppression on firefighter hydration. Study eligibility was assessed using strict inclusion and exclusion criteria. The included studies were critically appraised using the Downs and Black protocol and graded according to the Kennelly grading system. RESULTS: Ten studies met the eligibility criteria for this review. The average score for methodological quality was 55 %, ranging from 50 % (‘fair’ quality) to 61 % (‘good’ quality) with a ‘substantial agreement’ between raters (k = .772). Wildfire suppression was considered in five studies and structural fire suppression in five studies. Results varied across the studies, reflecting variations in outcome measures, hydration protocols and interventions. Three studies reported significant indicators of dehydration resulting from structural fire suppression, while two studies found mixed results, with some measures indicating dehydration and other measures an unchanged hydration status. Three studies found non-significant changes in hydration resulting from wildfire firefighting and two studies found significant improvements in markers of hydration. Ad libitum fluid intake was a common factor across the studies finding no, or less severe, dehydration. CONCLUSIONS: The evidence confirms that structural and wildfire firefighting can cause dehydration. Ad libitum drinking may be sufficient to maintain hydration in many wildfire environments but possibly not during intense, longer duration, hot structural fire operations. Future high quality research better quantifying the effects of these influences on the degree of dehydration is required to inform policies and procedures that ensure firefighter health and safety

New method for photoresist stripping

Vacuum dehydration of negatively working photoresist eliminates trace contamination of conventional stripping methods. The semiconductor substrate is coated with photoresist, exposed, developed, cured, and etched, and then placed in a vacuum. Following dehydration, the resist film is removable with ordinary solvents

Egg clutch dehydration induces early hatching in red-eyed treefrogs, Agalychnis callidryas

Terrestrial eggs have evolved repeatedly in tropical anurans exposing embryos to the new threat of dehydration. Red-eyed treefrogs, Agalychnis callidryas, lay eggs on plants over water. Maternally provided water allows shaded eggs in humid sites to develop to hatching without rainfall, but unshaded eggs and those in less humid sites can die from dehydration. Hatching responses of amphibian eggs to dry conditions are known from two lineages with independent origins of terrestrial eggs. Here, we experimentally tested for dehydration-induced early hatching in another lineage (Agalychnis callidryas, Phyllomedusidae), representing a third independent origin of terrestrial eggs. We also investigated how dehydration affected egg and clutch structure, and egg mortality. We collected clutches from a pond in Gamboa, Panama, and randomly allocated them to wet or dry treatments at age 1 day. Embryos hatched earlier from dry clutches than from wet clutches, accelerating hatching by ∼11%. Clutch thickness and egg diameter were affected by dehydration, diverging between treatments over time. Meanwhile, mortality in dry clutches was six-fold higher than in control clutches. With this study, early hatching responses to escape mortality from egg dehydration are now known from three anuran lineages with independent origins of terrestrial eggs, suggesting they may be widespread. Further studies are needed to understand how terrestrial amphibian eggs can respond to, or will be affected by, rapid changes in climate over the next decades.Fil: Salica, María José. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET - Salta. San Salvador de Jujuy; ArgentinaFil: Vonesh, James R.. Virginia Commonwealth University; Estados UnidosFil: Warkentin, Karen M.. Smithsonian Tropical Research Institute; Panamá. Boston University; Estados Unido

PENGARUH PEMBERIAN MINUMAN ISOTONIK TERHADAP MEMORI PADA KEADAAN DEHIDRASI

Background: Sport is one of popular activities throughout the world. One of the biggest problems found among athletes in sports is dehydration, which causes many bad health issues for athletes themselves. The bad health issues caused by dehydration, several of them are disturbance and decrease of the memory. Therefore, rehydration is required to overcome the bad effects of dehydration. Aim: To know the effect of rehydration on memory Method: This research uses experimental method. The research subjects are the medical students of Diponegoro University (n=31) whom being dehydrated and rehydrated with isotonic water. Their memories are measured by using code and memory tests. A changing of memories among groups is analyzed with Kruskal Wallis and continued with Mann-Whitney test. Result: It is found that there is a decrease of memories after dehydrating condition rather than before dehydrating condition. Wilcoxon test shows an increase of memory function after rehydration which is significant in group of isotonic water rehydration (p=0,006) and mineral water rehydration (p=0,026).Otherwise, there is a significant ecrease of memory function in group of non-rehydration (p=0,035). Furthermore, the result of Kruskal Wallis shows the significant difference (p=0,022) in memory test among groups. Conclusion: Dehydration decreases memory function, while rehydration with isotonic and mineral water can significantly increase memory function. Keywords: Rehydration, dehydration, memory, isotonic water, mineral water *Undergraduate of Faculty of Medicine Diponegoro University Semarang **Staff of Physiology Department Faculty of Medicine Diponegoro University Semaran

STUDY OF SOME PRETREATMENTS FOR OPTIMIZING THE DEHYDRATION OF BIOLOGICAL CARROTS

The experimental work proposed has tested the use of some pre-treatments to optimize the dehydration of biological carrots (var. Romance) The pre-treatments used were: 1) blanching (95°C) for 1.5 min, 2) blanching (70°) with citric acid 2% (w/v) for 2 min, 3) dipping in pectin’s 1% (w/v) for 1 min, 4) dipping in pectin’s 1% (w/v) with vacuum impregnation technology for 10 sec at 734 mbar. The aim of this work was to evaluate and compare the effects on carrot quality attributes. For this goal, the trial involved the use of various analytical techniques such as the enzyme activity test for peroxidase (POD), colorimetric analysis, determination of the total phenol content, extraction and quantification of carotenoids, rehydration process analysis. In addition, four semi-theoretical mathematical models were used to describe the pattern of dehydration of the pre-treated carrot washers. In light of the results obtained, the blanching pre-treatment at 70°C with 2% citric acid (w/v) has preserved more than all the nutritional characteristics of the carrot during the dehydration process. This pre-treatment showed an almost complete inactivation of the enzyme peroxidase (POD), an average dehydration rate of 6 hours, a colour angle (h) with a tint tending to red tones (the visual appearance is appreciated by some consumers and therefore considered a positive attribute in the choice of the product). Analysis of the carotenoid and total phenol content showed that blanching at 70°C with 2% citric acid was, like control and immersion in 1% pectin’s, the best pre-treatment with less loss of quality components (carotenoids and phenols) during dehydration. The work has also shown that the Logarithmic model can be used as the only model to predict moisture loss for all the dehydration pre-treatments used in experimentation

Controlled Rate Thermal Analysis and Differential Scanning Calorimetry of Sepiolites and Palygorskites

A series of sepiolites, palygorskites and "Rocky Mountain Leather" clay minerals have been analysed by controlled rate thermal analysis and differential scanning calorimetry. Eight weight loss steps are observed and are structure and composition dependent. Three dehydration steps and five dehydroxylation steps are observed. The mass spectrometric curve mimicked the differential thermogravimetric (DTGA) curve enabling the detailed determination of the dehydration and dehydroxylation step

Dehydration mechanism of a small molecular solid: 5-nitrouracil hydrate

Previous studies of the dehydration of 5-nitrouracil (5NU) have resulted in it being classified as a ‘‘channel hydrate’’ in which dehydration proceeds principally by the exit of the water molecules along channels in the structure. We have re-examined this proposal and found that in fact there are no continuous channels in the 5NU structure that would contribute to such a mechanism. Product water molecules would be immediately trapped in unlinked voids in the crystal structure and would require some additional mechanism to break loose from the crystal. Through a detailed structural analysis of the macro and micro structure of the 5NU as it dehydrates, we have developed a model for the dehydration process based on the observed development of structural defects in the 5NU crystal and the basic crystallography of the material. The model was tested against standard kinetic measurements and found to present a satisfactory account of kinetic observations, thus defining the mechanism. Overall, the study shows the necessity of complementing standard kinetic studies with a parallel macro and micro examination of the dehydrating material when evaluating the mechanisms of dehydration and decomposition processes