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We examined seasonal variation in urine concentration and fecal water content (FWC) of free-ranging bats inhabiting the tropical deciduous forest of the Chamela-Cuixmala Biosphere Reserve, Mexico, which is characterized by marked dry and rainy seasons. We tested the hypothesis that bats inhabiting this forest would exhibit seasonal physiological changes to maintain water balance. We predicted that bats would have higher urine concentrations and reduced FWC during the dry season. Our results were consistent with the 1st prediction for the insectivore, Parnell's mustached bat (Pteronotus parnellii), but not for the Jamaican fruit bat (Artibeus jamaicensis). Our data were consistent with our 2nd prediction for P. parnellii and the facultative nectarivore Pallas' long-tongued bat (Glossophaga soricina), but not for A. jamaicensis. Our findings indicate that for the bats we studied, the 2 routes by which water is lost were affected differently by seasonal changes in water availability as a function of feeding habits. DOI: 10.1644/09-MAMM-A-370.1. Key words: bats, fecal water loss, seasonality, urine concentration

Objective: To develop bioelectrical impedance analysis (BIA) equations to predict total body water (TBW) and fat-free mass (FFM) of Sri Lankan children. Subjects/Methods: Data were collected from 5- to 15-year-old healthy children. They were randomly assigned to validation (M/F: 105/83) and cross-validation (M/F: 53/41) groups. Height, weight and BIA were measured. TBW was assessed using isotope dilution method ([D.sub.2]O). Multiple regression analysis was used to develop preliminary equations and cross-validated on an independent group. Final prediction equation was constructed combining the two groups and validated by PRESS (prediction of sum of squares) statistics. Impedance index ([height.sup.2]/impedance; [cm.sup.2]/[ohm]), weight and sex code (male= 1; female= 0) were used as variables. Results: Independent variables of the final prediction equation for TBW were able to predict 86.3% of variance with root meanssquared error (RMSE) of 2.1 I. PRESS statistics was 2.1 I with press residuals of 1.2 I. Independent variables were able to predict 86.9% of variance of FFM with RMSE of 2.7 kg. PRESS statistics was 2.8 kg with press residuals of 1.4 kg. Bland Altman technique showed that the majority of the residuals were within mean bias [+ or -] 1.96 s.d. Conclusions: Results of this study provide BIA equation for the prediction of TBW and FFM in Sri Lankan children. To the best of our knowledge there are no published BIA prediction equations validated on South Asian populations. Results of this study need to be affirmed by more studies on other closely related populations by using multi-component body composition assessment. doi:10.1038/sj.ejcn.1602835; published online 15 August 2007 Keywords: bioelectrical impedance analysis; body composition; fat mass; obesity; Sri Lankan children, Introduction Assessment of body composition, especially fat mass (FM) and fat-free mass (FFM) is an important aspect in managing many obesity-related non-communicable diseases. However, the use of some methods such [...]

Administration of the bradykinin B2 receptor antagonist, HOE-140, increases the absorption of chloride (Cl-) and water in the rat medullary collecting duct (MCD). Though HOE-140 fails to influence the glomerular filtration rate, it reduces the urine flow rate, and the absolute and fractional Cl- excretion. These findings provide evidence for the regulatory role of renal kinins in water and Cl- excretion.

CHIP28 geometry is restricted by its intrinsic tryptophan fluorescence properties. Hydropathy analysis shows that three of the four tryptophans in CHIP28 occur in close proximity to membrane-spanning regions. The outer region of the bilayer shows the fourth tryptophan. Selective polar quenchers and those linked by membranes are used to examine tryptophan fluorescence in proteins whose complexities are identical. Tryptophan characteristics, their position and the influence of the agonists on the structure of the protein, are determined by this process.

A group of channel/pore proteins, which includes the lens protein MIP26, reveals the integral membrane protein CHIP28 as a prominent water channel. Circular dichroism and Fourier transform infrared spectroscopy are used to distill the functional, delipidated CHIP28, to homogeneity and to analyze its secondary geometry. Anion-exchange chromatography is used to distill and delipidate CHIP28 in the early stages. Beta-octylglucoside is used to solubilize N-lauroylsarcosine-stripped erythrocyte membranes before anion-exchange chromatography.

The morphology of the functional channel forming integral protein of 28 kD (CHIP28) water channels is analyzed using freeze-fracture EM. CHIP28 produces intramembrane particles (IMPs) which have regular morphological characteristics. Liposomes reconstituted with refined CHIP28 protein, CHO cells transfected with CHIP28, cDNA and native kidney tubule plasma membranes are located in IMPs.

Dual photon absorptiometry and total body water (TBW) facilitate the evaluation of fat-free mass (FFM) in 27 healthy elderly subjects. Both the techniques employed give an error-free value of FFM from TBW which includes a constant hydration factor of 0.732. This value is applicable to body composition analysis of the elderly. Variability FFM hydration in the subjects is also analyzed.

Human red blood cells, CHIP28, yields CHIP, a 28-kDa channel-forming integral membrane protein, which is identified to determine the molecular properties of membrane water channels. Osmosis, seen in CHIP, causes water-selective pore movement. Enhancement in osmotic water permeability is seen in Xenopus oocytes due to CHIP expression. Transmembrane movement of ions or other minute molecules is not permitted by CHIP. Permeability of unit water is determined by the recreation of distilled CHIP into proteoliposomes.

The water content of fat-free body mass (W/FFM) is lesser in young adults, in comparison with prepubescent children and older adults. A multicomponent estimation of FFM was conducted by analyzing the total water content of the body, the body density, and the regional bone mineral density. The variations in adult W/FFM were responsible for most errors in the fat percentage determination by two-component methods.

Decrease and toxication in water level in the body of old adults can cause depression, hyponatremia, anorexia and mental confusion. Homeostasis maintenance in the body of older adults requires water as a nutrient. Water also regulates nutrient transport, cell volume, body temperature and removal of wastes. The idea that intracellular water influences cumulative water in the body may not be correct, since variations in extracellular water also affects the water level in the human body.

Role of the renin-angiotensin system in drinking of seawater-adapted eels Anguilla japonica: a reevaluation. Am J Physiol Regulatory Integrative Comp Physiol 279: R1105-R1111, 2000.--The role of ANG II, a potent dipsogenic hormone, in copious drinking of seawater eels was examined. SQ-14225 (SQ), an angiotensin-converting enzyme inhibitor, infused intra-arterially at 0.01-1 [micro]g [multiplied by] [kg.sup.-1] [multiplied by] [min.sup.-1], depressed drinking and arterial blood pressure in a dose-dependent manner. The inhibition was accompanied by a small decrease in plasma ANG II concentration, which became significant at 1 [micro]g [multiplied by] [kg.sup.-1] [multiplied by] [min.sup.-1]. After the infusate was changed back to the vehicle, the depression of drinking and arterial pressure continued for [is greater than] 2 h, although plasma ANG II concentration rebounded above the level before SQ infusion. By contrast, infusion of anti-ANG II serum (0.01-1 [micro]g [multiplied by] [kg.sup.-l] [multiplied by] [min.sup.-1]) did not suppress drinking and arterial pressure, although plasma ANG II concentration decreased to undetectable levels. Plasma atrial natriuretic peptide and plasma osmolality. which influence drinking rate in eels, did not change during; SQ or antiserum infusions. These results suggest that the renin-angiotensin system plays only a minor role in the, vigorous drinking observed in seawater eels. The results also suggest that the antidipsogenic and vasodepressor effects of SQ in seawater eels are not due solely to the inhibition of ANG II formation in plasma. converting enzyme inhibition by SQ-14225; immunoneutralization of angiotensin II; water intake; blood pressure; atrial natriuretic peptide