Dehydration Index Research Articles

Dynamics of anti-Toxoplasma gondii antibodies and seroconversion during pregnancy and lactation in naturally infected goats

The objective of this work was to evaluate the dynamics of anti-T. gondii antibodies and seroconversion in naturally infected goats from the last third of pregnancy to 100 days of lactation and relate it to hematological and dehydration parameters. Blood samples were obtained from 56 goats in the different physiological states (pregnancy, kidding and lactation) as in different years (2019, 2021 and 2022). A total of 266 serum samples were obtained and evaluated by indirect fluorescent antibody test (IFAT) to end titer. The overall T. gondii seropositivity was 80.4% (45/56), with titers ranging from 100 to 25.600. The goats older than 3 years (4967 ± 1329) had significantly higher IFAT titers than the younger goats (2705 ± 681). The highest rate of positive seroconversion 31.1% (14/45) was found between kidding and 70 days of lactation; and of negative seroconversion 28.9% (13/45) between late pregnancy and kidding. The highest proportion of slightly dehydrated animals was found in the last third of pregnancy (14/25) and kidding (9/28). The correlation between seroconversion and T. gondii antibody titers was negative to the established dehydration index. These data suggest that in all physiological states and at different ages of goats, there is seroconversion which is not related to hydration status. Pregnancy, kidding and peak of lactation are stressful physiological periods, facilitating the reactivation of chronic T. gondii infections which are expressed by higher antibodies titers.

Effect of Lepidium perfoliatum seed gum — Oleic acid emulsion coating on osmotic dehydration and subsequent air-drying of apple cubes

The objective of this study was to investigate the effects of Lepidium perfoliatum seed gum (0, 0.5 and 1 % w/v) and oleic acid (0, 2 and 3 % v/v) coatings on the mass transfer and quality of osmotic dehydrated apple cubes. For this purpose, texture, color and microstructure of coated apple cubes were evaluated. Results showed that using Lepidium perfoliatum seed gum (LPSG) as a coating improved the properties of osmotic dehydrated apples. The value for water loss (WL)/solid gain (SG) increased when 0.5 % LPSG was used; however, at 1 % LPSG concentration, the WL/SG value decreased significantly. Apple cubes coated with 0.5 % LPSG and osmotic dehydrated for 120 min had the highest dehydration index (WL/SG). During the osmotic dehydration, coating with 0.5 % LPSG reduced the color changes and puffed structure, while it increased the hardness of the samples. Although oleic acid decreased the hardness of osmotic dehydrated apple cubes, there were no significant difference between the samples coated. The apple cubes coated with 0.5 % had the optimal mass transfer and physical properties. Therefore, this sample was then dried by hot air using three temperatures of 50, 60 and 70 °C. During hot air drying, the lowest effective diffusion coefficient, hardness, color change, shrinkage and porosity was observed for sample coated with LPSG. Dried sample at 60 °C had the minimum hardness and gumminess. By modeling the kinetics of drying the Midilli and Kucuk model was selected, since this model had the best conformity with experimental data.

Hydration In Athletes: A Literature Review

The aim of this study to review the most recent research on the factors that most influence hydration. This study review using the literature research from google scholar, PubMed, and Elsevier. Many athletes after training experience dehydration due to not consuming enough fluids and electrolytes before, during training, and competition. To assess hydration status cannot be determined by just one factor. The general recommendation of hydration status measures using accurate biomarkers to detect body water fluctuations of 3% of total body water (TBW), using dehydration index, body mass, or color of urine. Therefore, monitoring hydration status is very important to maintain athlete performance. Exercise increases hypohydration due to fluid losses so that should be given to fluid supplementation and intake from certain food for each athlete. The factor that most influences the athlete's hydration is sweat loss and fluid intake.

The relationship of dehydration and body mass index with the occurrence of atrial fibrillation in heart failure patients

Abstract Background/Introduction Heart failure (HF) and atrial fibrillation (AF) are two conditions that are likely to dominate the next years of cardiovascular (CV) care. These diseases frequently coexist and they can beget one another due to similar risk factors and similar pathophysiology. Purpose The aim of the study was to assess the relationship of dehydration, body mass index (BMI) and other indices with the occurrence of AF in HF patients. Methods The study included 113 patients [median age 64 years; 57.52% male] hospitalized due to HF. Baseline demographics, body mass analysis, echocardiographic results, key cardiopulmonary exercise test (CPET) parameters, six minute walk distance (6MWD) and Kansas City Cardiomyopathy Questionnaire (KCCQ) score were assessed. Results Of all patients, 23 (20.35%) had AF, and 90 (79.65%) had sinus rhythm (SR). Patients with AF were older (med. 66 vs 64 years; p=0.039), with higher BMI (32.02 vs. 28.51 kg/m2; p=0.017) and percentage of fat content (37.0 vs. 27.9%, p=0.014). They were more dehydrated, with a lower percentage of total body water (TBW%) (45.7 vs 50.0%; p=0.022). Clinically, patients with AF had more often higher New York Heart Association (NYHA) class (III vs II; p<0.001), shorter 6MWD (median 292.35 vs 378.4 m; p=0.001) and a lower KCCQ overall summary score (52.60 vs 73.96 points; p=0.002). Patients with AF had significantly lower exercise capacity as measured by peak oxygen consumption (peak VO2) (0.92 vs 1.26 mL/min, p=0.016), peak VO2/kg (11 vs. 15 mL/kg/min; p<0.001), and percentage of predicted VO2max (pp-peak VO2) (62.5 vs 70.0; p=0.010). We also found VE/VCO2 (med.33.85 vs 32.20; p=0.049) to be higher and peak oxygen pulse (8.5 vs 11 mL/beat; p=0.038) to be lower in patients with AF than in patients without AF. In a multiple logistic regression model higher BMI (OR 1.23 per unit increase, p<0.001) and higher left atrial volume index (LAVI) (OR 1.07 per unit increase, p=0.03), lower tricuspid annular plane systolic excursion (TAPSE) (OR 0.74 per unit increase, p=0.03) and lower TBW% in body mass analysis (OR 0.90 per unit increase, p=0.03) were independently related to AF in patients with HF. Conclusions Increased volume of left atrium and right ventricular systolic dysfunction are well-known predictors of AF occurrence in patients with HF, but hydration status and increased body mass also seem to be important factors of AF in HF patients. Funding Acknowledgement Type of funding sources: None. Figure 1

Can Total Body Resistance Measured Using Bioelectrical Impedance Analysis Be the Index of Dehydration in Older Japanese Patients?

BackgroundDehydration in older patients has long been considered a significant health problem because it implies increased morbidity and mortality. However, dehydration is detected by a combination of physical signs and blood tests. For older people dwelling at home and in nursing homes, a simple and non-invasive method for detecting dehydration by caregivers is needed. The total body resistance is measured using bioelectrical impedance analysis and is known as an indicator of dehydration. There are no data from older Japanese patients on this issue. We performed this study to examine the relationship between dehydration and total body resistance in Japan.MethodsWe performed blood tests and measured bioelectrical impedance in older outpatients aged ≥ 65 years from the Internal Medicine Department at Mito Kyodo General Hospital. Patients were classified as dehydrated and non-dehydrated using the dehydration index with a blood urea nitrogen/creatinine ratio > 20, and the mean total body resistance was compared between the two groups.ResultsEighty-one patients were recruited in the study. In the dehydrated group, the mean total body resistance was 439 Ω at 50 kHz, which was significantly higher than that in the non-dehydrated group (408 Ω, P = 0.038).ConclusionsThe total body resistance measurements can be used for simple assessment of dehydration among older Japanese patients.

Development of a diurnal dehydration index for spring barley phenotyping.

Spectral and thermal assessments may enable the precise, high-throughput and low-cost characterisation of traits linked to drought tolerance. However, spectral and thermal measurements of the canopy water status are influenced by the crops' soil coverage, the size of the biomass and other properties such as the leaf angle distribution. The aim of this study was to develop a referenced spectral method that would be minimally influenced by potentially perturbing factors for retrieving the water status of differing cultivars. Sixteen spring barley cultivars were grown in field trials under imposed drought stress, natural drought stress and irrigated conditions. The relative leaf water content of barley plants declines diurnally from pre-dawn until the afternoon, and other plant traits such as the biomass change little throughout the day. As an indicator of the current drought stress, pre-dawn and afternoon values of the relative leaf water content were assessed spectrally. Diurnal changes in reflectance are only slightly influenced by other perturbing factors. A new spectral index (diurnal dehydration index) was developed by using the wavelengths 730 and 457nm collected from an active spectrometer. This index allowed the differentiation of the drought tolerance of barley plants. The diurnal dehydration index was significantly related to final biomass, grain yield and harvest index and significantly different between cultivars. Compared with other indices, the diurnal dehydration index offered a higher stability in retrieving the water status of barley plants. Due to its diurnal assessment, the index was barely influenced by the differences in cultivars biomass at the time of measurement. It may represent a valuable tool for assessing the water status or drought tolerance in breeding nurseries.

Relationship between seasonal weather changes, risk of dehydration, and incidence of severe bradyarrhythmias requiring urgent temporary transvenous cardiac pacing in an elderly population

There is little information on any seasonal variations or meteorological factors associated with symptomatic bradyarrhythmias requiring cardiac pacing. The aim of this single-center study was to investigate the seasonal distribution of the incidence of severe, life-threatening bradyarrhythmias requiring urgent temporary transvenous cardiac pacing in an elderly population. Consecutive patients who underwent urgent temporary transvenous cardiac pacing between 2007 and 2012 were enrolled. The baseline characteristics of the patients and some meteorological parameters, including the calculation the daily heat index (HI), were recorded. During the study period, 79 consecutive patients (mean age 82 ± 8 years, 41% male) underwent urgent temporary transvenous cardiac pacing, mainly for third-degree atrioventricular block (79%). The incidence of bradyarrhythmias was significantly higher in summer than in the other seasons (P < 0.001). Moreover, the highest incidence was observed in months with HI > 90 °F for >3 h per day for at least 10 days (P < 0.001). A direct correlation was found between the average monthly temperature and the monthly number of patients undergoing temporary cardiac pacing (r = 0.54, P < 0.001). Compared with other patients, those observed during the hottest months were significantly older and more frequently affected by chronic disabling neurological diseases (all P < 0.05). In addition, they more frequently showed biochemical indices of dehydration, renal function impairment and hyperkalemia (all P < 0.05). This study showed an increased incidence of severe bradyarrhythmias in an elderly population during the hottest months of the year. In these months, in subjects characterized by increased susceptibility to dehydration, the risk of developing bradyarrhythmias was increased significantly.

An Aggregate Urine Analysis Tool to Detect Acute Dehydration

Urine sampling has previously been evaluated for detecting dehydration in young male athletes. The present study investigated whether urine analysis can serve as a measure of dehydration in men and women of a wide age span. Urine sampling and body weight measurement were undertaken before and after recreational physical exercise (median time: 90 min) in 57 volunteers age 17-69 years (mean age: 42). Urine analysis included urine color, osmolality, specific gravity, and creatinine. The volunteers' body weight decreased 1.1% (mean) while they exercised. There were strong correlations between all 4 urinary markers of dehydration (r = .73-.84, p < .001). Researchers constructed a composite dehydration index graded from 1 to 6 based on these markers. This index changed from 2.70 before exercising to 3.55 after exercising, which corresponded to dehydration of 1.0% as given by a preliminary reference curve based on seven previous studies in athletes. Men were slightly dehydrated at baseline (mean: 1.9%) compared with women (mean: 0.7%; p < .001), though age had no influence on the results. A final reference curve that considered both the present results and the 7 previous studies was constructed in which exercise-induced weight loss (x) was predicted by the exponential equation x = 0.20 dehydration index1.86. Urine sampling can be used to estimate weight loss due to dehydration in adults up to age 70. A robust dehydration index based on four indicators reduces the influence of confounders.

The Acute Gastrointestinal Subsyndrome of the Acute Radiation Syndrome

The development of medical countermeasures against the acute gastrointestinal subsyndrome of the acute radiation syndrome in humans requires well characterized and validated animal models. These models must adhere to the criteria of the U.S. Food and Drug Administration's Animal Rule and consider the natural history and clinical context of the human radiation response and treatment in the nuclear terrorist scenario. The models must define the radiation dose- and time-dependent relationships for mortality and major signs of morbidity, including concurrent damage in other organs, such as the bone marrow, that may contribute to the overall mortality and morbidity. There are no such models of the gastrointestinal syndrome in response to total-body irradiation in the nonhuman primate. Herein, these parameters are defined for the rhesus macaque exposed to potentially lethal doses of radiation and administered medical management. Rhesus macaques (n = 69) were exposed bilaterally to 6 MV linear accelerator-derived photon total body irradiation to midline tissue (thorax) doses ranging from 10.0 to 14.0 Gy at 0.80 Gy min(-1). Following irradiation, all animals were administered supportive care consisting of fluids, anti-emetics, anti-diarrheal medication, antibiotics, blood transfusions, analgesics, and nutrition. The primary endpoint was survival at 15 d post-irradiation. Secondary endpoints included indices of dehydration, diarrhea, weight loss, hematological parameters, cellular histology of the small and large intestine, and mean survival time of decedents. Mortality within the 15-d in vivo study defined the acute gastrointestinal syndrome and provided an LD30/15 of 10.76 Gy, LD50/15 of 11.33 Gy, and an LD70/15 of 11.90 Gy. Intestinal crypt and villus loss were dose- and time-dependent with an apparent nadir 7 d post-irradiation and recovery noted thereafter. Severe myelosuppression and thrombocytopenia were noted in all animals, requiring the administration of antibiotics and blood transfusions. The model defines the dose response relationship and time course of acute gastrointestinal syndrome-induced morbidity and mortality in the rhesus macaque.

Dehydration among Long-Term Care Elderly Patients with Oropharyngeal Dysphagia

Introduction: Long-term care (LTC) residents, especially the orally fed with dysphagia, are prone to dehydration. The clinical consequences of dehydration are critical. The validity of the common laboratory parameters of hydration status is far from being absolute, especially so in the elderly. However, combinations of these indices are more reliable. Objective: Assessment of hydration status among elderly LTC residents with oropharyngeal dysphagia. Methods: A total of 28 orally fed patients with grade-2 feeding difficulties on the functional outcome swallowing scale (FOSS) and 67 naso-gastric tube (NGT)-fed LTC residents entered the study. The common laboratory, serum and urinary tests were used as indices of hydration status. The results were considered as indicative of dehydration and used as ‘markers of dehydration’, if they were above the accepted normal values. Results: The mean number of dehydration markers was significantly higher in the FOSS-2 group (3.8 ± 1.3 vs. 2 ± 1.4, p = 0.000). About 75% of these FOSS-2 patients had ≧4 dehydration markers versus 18% of the NGT-fed group (p = 0.000). A low urine output (<800 ml/day) was significantly more common in the FOSS-2 group (39 vs. 12%, p = 0.002). Above normal values of blood urea nitrogen (BUN), BUN/serum creatinine ratio (BUN/S_Cr), urine/serum osmolality ratio (U/S_Osm), and urine osmolality U_Osm, were significantly more frequent in the dehydration-prone FOSS-2 group. This combination of 4 indices was present in 65% of low urine output patients. In contrast, it was present in only 36% of the higher urine output patients (p = 0.01). Patients with a ‘normal’ daily urine output (>800 ml/day) also had a significant number (2 ± 1.5) of positive indices of dehydration. Conclusions: Dehydration was found to be common among orally fed FOSS-2 LTC patients. Surprisingly, probable dehydration, although of a mild degree, was not a rarity among NGT-fed patients either. The combination of 4 parameters, BUN, BUN/S_Cr, U/S_Osm and U_Osm, offers reasonable reliability to be used as an indication of dehydration status in daily clinical practice.

Temperature Fields in the Tropical Tropopause Transition Layer

Abstract There has been increasing recognition of the role of the tropical tropopause layer (TTL) in determining stratospheric water vapor concentrations—the TTL being a layer of transition between air showing tropospheric properties below and stratospheric properties above. This study investigates the spatial structure of temperatures in the TTL. A dehydration index based on the atmospheric region with temperatures colder than a specific reference temperature was defined to examine the TTL temperature structure and possible influences on stratospheric water vapor. The results indicate that dehydration regions with cold temperatures (e.g., <190 K) occur mainly over the western Pacific and are about 1.5–2.0 km in depth during Northern Hemisphere winter. The dehydration index is mainly dependent on the annual cycle of the TTL temperatures, but is strongly affected by interannual variations associated with the quasi-biennial oscillation (QBO) and El Nino–Southern Oscillation (ENSO). Dehydration regions with ...

Dehydration and venous thromboembolism after acute stroke.

Although it is widely assumed that dehydration predisposes to venous thromboembolism (VTE), there are no clinical studies to support this. To evaluate the relationship between biochemical indices of dehydration and VTE after acute ischaemic stroke (AIS). Prospective observational study. Unselected AIS patients (n = 102) receiving standard thromboprophylaxis with aspirin and graded compression stockings, underwent serial measurements of serum urea, creatinine and osmolality, and were screened for VTE using magnetic resonance direct thrombus imaging. Serum osmolality of >297 mOsm/kg, urea >7.5 mmol/l and urea:creatinine ratio (mmol:mmol) >80 a few days post-AIS were associated with odds ratios for VTE of, respectively, 4.7, 2.8 and 3.4 (p = 0.02, 0.05, 0.02) on multivariable analysis. Dehydration after AIS is strongly independently associated with VTE, reinforcing the importance of maintaining adequate hydration in these patients.

Individuality and responsiveness of biochemical indices of dehydration in hospitalized elderly patients

Background: dehydration is common in elderly patients, but difficult to detect, by either an initial assessment of fluid balance or by monitoring fluid balance over time. In clinical chemistry, population-based reference ranges arc only of value for monitoring individual patients if within-subject variability in serial test results over time is larger than between-subject variability. This may have important implications in monitoring fluid balance. Ainu to assess the within- and between-subject variability of serial laboratory test results in euvolaemia and their responsiveness to dehydration in elderly patients. Methods: over 16 months, 218 patients were admitted to the geriatric department and 53 consented to participate. Fluid balance was assessed twice a week by physical examination, laboratory tests and weighing. Changes in fluid balance were quantified by measuring total body and extracellular water applying deuterium- and bromide-dilution techniques. Within- and between-subject variability in euvolaemia and responsiveness indexes (RI) for dehydration were calculated for haematocrit, serum sodium, urea and creatinine concentrations and for the urea/creatinine ratio. Results: during hospitalization 14 patients suffered from dehydration and 27 remained euvolaemic. Data from 12 overhydrated patients were excluded. In a mean study period of 30 days, each patient's fluid balance was assessed 6.3 (1.9) times. This resulted in 1084 laboratory tests and 271 assessments of fluid balance. In all quantities withinsubject variability was much smaller than between-subject variability in euvolaemia. Responsiveness of creatinine (mean RI = 2.5) was best and similar to the RI of serial weights (mean RI = 2.9). Conclusion: population-based reference ranges are of limited value in monitoring fluid balance. Repeatedly measuring plasma creatinine, combined with physical examination and weighing is the best way to monitor fluid balance in elderly patients.

The depletion of glycogen stores and indices of dehydration in transported broilers

Broilers were either not transported or were transported for 2, 4 or 6 hours after having been subjected to food withdrawal times of less than one hour or of ten hours. The birds were then slaughtered using normal commercial practices. The longer period of food deprivation reduced liver weight and glycogen content, and circulating glucose concentrations. It also elevated the ultimate pH value (pHu) in the biceps muscle and by implication, therefore, reduced its glycogen content. With longer journey times, liver weight and glycogen content decreased. Transport had an inconsistent effect on glycogen concentration in the pectoral muscle but progressively reduced its pHu. In contrast, pHu in the biceps progressively increased, by implication because transport depleted muscle glycogen levels. Birds transported further had higher concentrations of total protein in their plasma which, though this was not significant, also had a higher osmolality. This suggests that transported birds became dehydrated. Additionally, the depletion of body glycogen stores might be associated with the perception of fatigue.

Relationship between freezing tolerance and shoot water relations of western red cedar

Freezing tolerance and shoot water relations parameters of western red cedar (Thuja plicata Donn) seedlings were measured every 2 weeks from October 1989 to April 1990. Freezing tolerance, measured by freeze-induced electrolyte leakage, showed seasonal shifts in the temperature causing 50% foliage electrolyte leakage (LT(50)). The LT(50) value was -4 degrees C in October, it decreased to -20 degrees C in February and then increased to -6 degrees C in April. The foliage index of injury at -10 degrees C (II(-10)) also showed seasonal shifts from a high of 98% in October to a low of 18% in February followed by an increase to 82% in April. Osmotic potentials at saturation (Psi(s(sat))) and turgor loss point (Psi(s(tlp))) were, respectively, -1.07 and -1.26 MPa in October, -1.57 and -2.43 MPa in January, and -1.04 and -1.86 MPa in April. Dry weight fraction (DWF) increased and symplastic volume at full turgor (V(o)) decreased during the fall-winter acclimation phase, whereas DWF decreased and V(o) increased during the late winter-spring deacclimation phase. Relationships between seasonal patterns of freezing tolerance and shoot water relations parameters showed that LT(50) and II(-10) decreased linearly as Psi(s(tlp)) and V(o) decreased and DWF increased. There was no discernible difference in the relationship during fall acclimation or spring deacclimation. The freezing dehydration index at -10 degrees C (FDI(-10)) declined from 0.69 in November to 0.41 in February and increased to 0.56 in April. The value of II(-10) decreased linearly as FDI(-10) decreased, although a measurement made on actively growing spring foliage did not fit this relationship. The results indicate that seasonal changes in freezing tolerance of western red cedar are partially due to changes in tissue water content, symplastic volume, passive osmotic adjustment and FDI(-10).

Influence of cold hardening on water relations of three Eucalyptus species.

Water relations of three Eucalyptus species (E. x trabutii Wilm., E. viminalis Labill., E. dalrympleana Maid.), widely planted in the Mediterranean basin, were analyzed throughout an entire year in relation to natural cold hardening. Osmotic potential, both at saturation and at the turgor loss point, showed a greater reduction during hardening in the more frost-resistant E. viminalis and E. dalrympleana than in the more frost-sensitive E. x trabutii. The hardening capabilities of all species were analyzed in relation to the freezing dehydration index, FDI, a parameter derived from pressure-volume analysis which represents the water lost when cells, initially at the turgor loss point, attain thermodynamic equilibrium with extraplasmatic ice. The FDI at the killing temperature showed little variation either between frost-sensitive and frost-resistant species, or between hardened and non-hardened plants. The index may, therefore, be useful for evaluating a plant's potential for injury by freeze-induced desiccation.

The effect of water abstention on milk synthesis in lactating women.

The effects of dehydration on mechanisms of water balance and milk synthesis were investigated in ten lactating Gambian women who were fasting during Ramadan. Ten non-pregnant, non-lactating women acted as controls. Fasting consisted of total water abstention from 05.00 hours to 19.30 hours and was accompanied by high insensible water losses. Lactating women lost 7.6% of their total body water between 07.00 hours and 19.00 hours. Control subjects lost significantly less. Plasma indices of dehydration (osmolality, sodium, uric acid) showed a greater rise in the lactating women than in the control subjects over the period of fasting. However, the 19.00 hours values remained in the normal range obtained on non-Ramadan days. During Ramadan the lactating women restricted their urinary output to a lesser degree than the controls, and for much of the day their urine was also less concentrated. The lactating women appeared to have adapted by superhydrating themselves overnight. This resulted in very low urine concentrations (osmolality, sodium, urea, creatinine) in morning samples. Urine concentrations approached, but did not exceed, non-Ramadan levels by late afternoon. The daily water turnover of 6.4 litres in the lactating women was 2 litres greater than in the controls. This difference was much greater than that required for milk synthesis (500 ml) and may represent a further protective mechanism. Fasting caused changes in milk osmolality, lactose, sodium and potassium concentrations indicative of a marked disturbance of milk synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Hyperaldosteronism in ketoacidosis and in poorly controlled non-ketotic diabetes.

PLASMA aldosterone concentrations were measured in 14 patients in diabetic ketoacidosis and in 20 patients with poorly controlled non-ketotic diabetes, both before treatment and again when metabolic control was achieved. Plasma aldosterone was above normal in 12 of 14 patients in ketoacidosis and there was a highly significant fall in mean plasma aldosterone concentration when metabolic control improved. Plasma aldosterone concentration in ketoacidosis was significantly related to plasma angiotensin //, arterial pH and indirect indices of dehydration. Plasma aldosterone was also above normal before treatment in 7 of 20 patients with poorly controlled non-ketotic diabetes. When metabolic control improved there was a small but significant reduction in mean plasma aldosterone concentration. However, plasma aldosterone and angiotensin were not significantly related in these patients.

Neurophysin(s) of the golden hamster (Mesocricetus auratus) and the effects of saline imbibition.

The neural lobe of the golden hamster contains one major and two minor proteins. The major protein was identified as a neurophysin in view of its electrophoretic properties, its high cysteine content and its depletion from the neural lobe upon saline imbibition. The depletion of neurophysin and vasopressin from the neural lobe and the alterations of several indices of dehydration in the blood of the hamster were less than those found in the rat upon saline imbibition, suggesting that the hamster has a greater ability to adapt to conditions in which water is scarce.

COAGULATION OF AQUEOUS POLYMER SOLUTIONS BY INORGANIC ELECTROLYTES

As a first step of explicating the spinning mechanism of viscose rayon, dehydration index of aqueous inorganic electrolyte solutions was studied. Sonic velocity in the solutions was measured by a ultrasonic interferometer and the amount of hydration was calculated according to Wada and coworkers. As a criterion of dehydration ability of electrolyte solutions, following formula was proposed.where s: dehydration index of electrolyte solution (%), v2: amount of hydration (cc/g solute), d0: density of solvent (g/cm3), andm: concentration of electrolyte solution (%).The values of s thus obtained were compared with the experimental results of coagulation of polyvinyl alcohol and methyl cellulose solutions. As for sulphates such as Na2SO4, Li2SO4, MgSO4, ZnSO4, CuSO4 and Al2 (SO4)3 and nitrates such as KNO3 and NH4NO3, it was found that the coagulation index obtained by dehydration index was nearly equal to the coagulation index obtained by coagulation experiments. Consequently s was considered to be adequate to use as a criterion of dehydrating power of electrolyte solutions. Using the dehydration index, coagulation of aqueous Na-cellulose xanthate solution by inorganic salts was investigated. By comparing the dehydration index of inorganic electrolyte solutions with the results of coagulation experiment of polyelectrolyte solution, following conclusions were obtained.The coagulation of aqueous Na-cellulose xanthate solution by inorganic salts is understood by three mechanisms.a) Dehydration is dominant.(salts of Na+, Li+ and Mg++)b) The interaction between the polyelectrolyte and inorganic ions is dominant.(salts of Zn++, Cu++)c) Intermediate between a) and b)(salts of K+ and NH+4)