Microbiome-driven allergic lung inflammation is ameliorated by short-chain fatty acids.

The mammalian gastrointestinal tract harbors a microbial community with metabolic activity critical for host health, including metabolites that can modulate effector functions of immune cells. Mice treated with vancomycin have an altered microbiome and metabolite profile, exhibit exacerbated T helper type 2 cell (Th2) responses, and are more susceptible to allergic lung inflammation. Here we show that dietary supplementation with short-chain fatty acids (SCFAs) ameliorates this enhanced asthma susceptibility by modulating the activity of T cells and dendritic cells (DCs). Dysbiotic mice treated with SCFAs have fewer interleukin-4 (IL4)-producing CD4+ T cells and decreased levels of circulating immunoglobulin E (IgE). In addition, DCs exposed to SCFAs activate T cells less robustly, are less motile in response to CCL19 in vitro, and exhibit a dampened ability to transport inhaled allergens to lung draining nodes. Our data thus demonstrate that gut dysbiosis can exacerbate allergic lung inflammation through both T cell- and DC-dependent mechanisms that are inhibited by SCFAs.

Lake bathymetry and species occurrence predict the distribution of a lacustrine apex predator.

This study examined the abiotic and biotic characteristics of ecosystems that allow expression of a life history called ferox trout, the colloquial name given to brown trout Salmo trutta adopting a piscivorous life history strategy, an apex predator in post-glacial lakes in northern Europe. One hundred and ninety-two lakes in Scotland show evidence of currently, or historically, supporting ferox S. trutta; their presence was predicted in logistic models by larger and deeper lakes with a large catchment that also support populations of Arctic charr Salvelinus alpinus.

Scalable synthesis of a biocompatible, transparent and superparamagnetic photoresist for microdevice fabrication.

The functionalization of photoresists with colloids has enabled the development of novel active and passive components for microfabricated devices. Incorporation of colloidal particles often results in undesirable reductions in photolithographic fidelity and device transparency. We present a novel photoresist composite incorporating poly(methyl methacrylate-co-methacrylic acid) (PMMA/MMA), the epoxy resin 1002F and colloidal maghemite nanoparticles to produce a stable, transparent and biocompatible photoresist. The composite photoresist was prepared in a scalable fashion in batches up to 1 kg with the particles remaining dispersed during room-temperature storage for at least 6 months. Following photolithography to form films, the nanoparticle size remained well below that of visible-light wavelengths as demonstrated by electron microscopy. Structures fabricated from the photoresist by conventional photolithography displayed aspect ratios greater than ten. When grown on the photoresist, the metabolic rate of HeLa cells was unchanged relative to cells grown on glass. Primary murine mesenchymal stem cells also displayed a normal morphology on the resist surface. The ability to manipulate microstructures formed from the composite was demonstrated by magnetically collecting clonal colonies of HeLa cells from a micropallet array. The transparency, biocompatibility, scalable synthesis and superparamagnetic properties of the novel composite address key limitations of existing magnetic composites.

Myeloid cell-specific expression of Ship1 regulates IL-12 production and immunity to helminth infection.

Helminth infection leads to the local proliferation and accumulation of macrophages in tissues. However, the function of macrophages during helminth infection remains unclear. SH2-containing inositol 5'-phosphatase 1 (Ship1, Inpp5d) is a lipid phosphatase that has been shown to play a critical role in macrophage function. Here, we identify a critical role for Ship1 in the negative regulation of interleukin (IL)-12/23p40 production by macrophages during infection with the intestinal helminth parasite Trichuris muris. Mice with myeloid cell-specific deletion of Ship1 (Ship1(ΔLysM) mice) develop a non-protective T-helper type 1 cell response and fail to expel parasites. Ship1-deficient macrophages produce heightened levels of IL-12/23p40 in vitro and in vivo and antibody blockade of IL-12/23p40 renders Ship1(ΔLysM) mice resistant to Trichuris infection. Our results identify a critical role for the negative regulation of IL-12/23p40 production by macrophages in the development of a protective T(H)2 cell response.

Microtubule turnover in ooplasm biopsy reflects ageing phenomena in the parent oocyte.

Oviductal oocytes retrieved from superovulated B6D2F1 mice at 13.5, 16 and 19 h after human chorionic gonadotrophin (HCG) (groups A, B and C respectively, n = 382) were micromanipulated to obtain 12-20 mum sized ooplasm biopsy fragments. Experiments were divided into three sets. Ooplasmic microtubule dynamics were studied in ooplasm biopsy specimens and parent oocytes (set 1) and ooplasm biopsy specimens (set 2), whilst zona pellucida dissolution time, cortical granule loss and spindle/chromatin morphology using confocal microscopy were also studied in parent oocytes (set 2). Oocytes withstood oocyte biopsy with a high survival rate (98.2%) and the biopsied oocytes underwent successful fertilization and development (set 3). An absolute one-to-one correlation was seen between the oocyte biopsy specimens and the parent oocytes in terms of ooplasmic microtubule dynamics (set 1), and increased ooplasmic microtubule dynamics in oocyte biopsy specimens paralleled ageing phenomena in the parent oocytes (set 2). Zona pellucida dissolution time was significantly lower in parent oocytes from group A versus groups B (P = 0.032), and C (P < 0.001). (Groups A, B, C include minimal, moderate, increased ooplasmic microtubule dynamics in oocyte biopsy specimens respectively.) Oocyte cortical granule loss and spindle/chromatin abnormalities were mainly seen in group C (P < 0.001). Oocyte biopsy can thus be applied to judge age-related changes in the parent oocytes.

The role of SHIP1 in macrophage programming and activation.

The SHIP1 (SH2-containing inositol-5'-phosphatase 1) acts as a negative regulator of proliferation, survival and end cell activation in haemopoietic cells. It does so, at least in part, by translocating to membranes after extracellular stimulation and hydrolysing the phosphoinositide 3-kinase-generated second messenger, PtdIns(3,4,5)P(3) to PtdIns(3,4)P(2). SHIP1(-/-) mice have, as a result, an increased number of neutrophils and monocyte/macrophages because their progenitors display enhanced survival and proliferation. These mice also suffer from osteoporosis because of an increased number of hyperactive osteoclasts and a significant neutrophil infiltration of the lungs. Interestingly, SHIP1(-/-) mice do not display endotoxin tolerance and we have found that lipopolysaccharide-induced endotoxin tolerance is contingent on up-regulating SHIP1, through the production of autocrine-acting transforming growth factor-beta, in bone-marrow-derived macrophages and mast cells. Intriguingly, unlike bone-marrow-derived macrophages, SHIP1(-/-) peritoneal and alveolar macrophages produce 10-fold less NO than wild-type macrophages because these in vivo-generated macrophages have very high arginase I levels and this enzyme competes with inducible nitric oxide synthase for the substrate L-arginine. It is probable that, in the face of chronically increased PtdIns(3,4,5)P(3) levels in their myeloid progenitors, SHIP1(-/-) mice display a skewed development away from M1 (killer) macrophages (which have high inducible nitric oxide synthase levels and produce NO to kill microorganisms and tumour cells), towards M2 (healing) macrophages (which have high arginase levels and produce ornithine to promote host-cell growth and collagen formation). This skewing probably occurs to avoid septic shock and suggests that the phosphoinositide 3-kinase pathway plays a critical role in programming macrophages.

The plasma membrane of microaerophilic protists: oxidative and nitrosative stress.

The trans-plasma-membrane electrochemical potential of microaerophilic protists was monitored by the use of voltage-sensitive charged lipophilic fluorophores; of the many available probes, the anionic oxonol dye bis(1,3-dibarbituric acid)-trimethine oxonol [DiBAC(4)(3)] is an example of one which has been successfully employed using fluorescence microscopy, confocal laser-scanning microscopy and flow cytometry. Several microaerophilic protists have been investigated with this dye; these were Giardia intestinalis, Trichomonas vaginalis, Tritrichomonas foetus, Hexamita inflata and Mastigamoeba punctachora. Under conditions where they exhibit normal vitality, these organisms exclude DiBAC(4)(3) by virtue of their maintenance of a plasma-membrane potential (negative inside). Uptake of the fluorophore is indicative of disturbance to this membrane (i.e. by inhibition of pump/leak balance, blockage of channels or generation of ionic leaks), and is indicative of metabolic perturbation or environmental stress. Here, it is shown that oxidative or nitrosative stress depolarizes the plasma membranes of the aforementioned O(2)-sensitive organisms and allows DiBAC(4)(3) influx. Oxonol uptake thereby provides a sensitive and early indication of plasma-membrane perturbation by agents that may lead to cytotoxicity and eventually to cell death by necrotic or apoptotic pathways.

Regulation of salt gland, gut and kidney interactions.

Marine birds can drink seawater because their cephalic 'salt' glands secrete a sodium chloride (NaCl) solution more concentrated than seawater. Salt gland secretion generates osmotically free water that sustains their other physiological processes. Acclimation to saline induces interstitial water and Na move into cells. When the bird drinks seawater, Na enters the plasma from the gut and plasma osmolality (Osm(pl)) increases. This induces water to move out cells expanding the extracellular fluid volume (ECFV). Both increases in Osm(pl) and ECFV stimulate salt gland secretion. The augmented intracellular fluid content should allow more rapid expansion of ECFV in response to elevated Osm(pl) and facilitate activation of salt gland secretion. To fully utilize the potential of the salt glands, intestinally absorbed NaCl must be reabsorbed by the kidneys. Thus, Na uptake at gut and renal levels may constrain extrarenal NaCl secretion. High NaCl intake elevates plasma aldosterone concentration of Pekin ducks and aldosterone stimulates intestinal and renal water and sodium uptake. High NaCl intake induces lengthening of the small intestine of adult Mallards, especially males. High NaCl intake has little effect on glomerular filtration rate or tubular sodium Na uptake of birds with competent salt glands. Relative to body mass, kidney mass and glomerular filtration rate (GFR) are greater in birds with salt glands than in birds that do not have them. Birds with salt glands do not change GFR, when they drink saline. Thus, their renal filtrate contains excess Na that is, in some species, almost completely renally reabsorbed and excreted in a more concentrated salt gland secretion. Na reabsorption by kidneys of other species, like mallards is less complete and their salt glands make less concentrated secretion. Such species may reflux urine into the hindgut, where additional Na may also be reabsorbed for extrarenal secretion. During exposure to saline, marine birds maintain elevated aldosterone levels despite high Na intake. Marine birds are excellent examples of physiological plasticity.

The role of SHIP in cytokine-induced signaling.

The phosphatidylinositol (PI)-3 kinase (PI3K) pathway plays a central role in regulating many biological processes via the generation of the key second messenger PI-3,4,5-trisphosphate (PI-3,4,5-P3). This membrane-associated phospholipid, which is rapidly, albeit transiently, synthesized from PI-4,5-P2 by PI3K in response to a diverse array of extracellular stimuli, attracts pleckstrin homology (PH) domain-containing proteins to membranes to mediate its many effects. To ensure that the activation of this pathway is appropriately suppressed/terminated, the ubiquitously expressed tumor suppressor PTEN hydrolyzes PI-3,4,5-P3 back to PI-4,5-P2 while the 145-kDa hemopoietic-restricted SH2-containing inositol 5'- phosphatase, SHIP (also known as SHIP1), the 104-kDa stem cell-restricted SHIP (sSHIP) and the more widely expressed 150-kDa SHIP2 hydrolyze PI-3,4,5-P3 to PI-3,4-P2. In this review we will concentrate on the properties of the three SHIPs, with special emphasis being placed on the role that SHIP plays in cytokine-induced signaling.

Effect of saline acclimation on body water and sodium compartmentalization in Pekin ducks (Anas platyrhynchos).

The compartmentalization of body fluids was measured in individual Pekin ducks ( Anas platyrhynchos) drinking freshwater and after sequential acclimation to 300 mM NaCl and 400 mM NaCl. Total body water, extracellular fluid volume, plasma volume and exchangeable sodium pool were measured using (3)H(2)O, [(14)C]-polyethylene glycol, Evans Blue dye, and (22)Na dilution, respectively. Following acclimation to 300 mM NaCl, body mass decreased, but total body water and total exchangeable sodium pool were unaltered. Na and water were redistributed from the extracellular fluid (interstitial fluid) compartment into the intracellular fluid compartment. Following further acclimation to 400 mM NaCl, body mass, total body water and intracellular fluid volume decreased, but exchangeable sodium pool and extracellular fluid volume were unchanged. Our results suggested that, when Pekin ducks drink high but tolerable salinities, they maintain total body water, but redistribute Na(+) and water from interstitial fluid to the intracellular fluid compartment. When stressed beyond their ability to maintain total body water, they lose water from the intracellular fluid.

Effect of saline intake on water flux and osmotic homeostasis in Pekin ducks (Anas platyrhynchos).

The physiological regulation of body water volume and concentration was evaluated in Pekin ducks, Anas platyrhynchos, slowly acclimated to increasingly saline drinking water (six equal 75 mM NaCl increments). Body mass, total body water (TBW), water flux, plasma osmolality (Osm(pl)), and ionic and osmoregulatory hormone concentrations were measured at the end of each increment. The salinity at which each variable deviates from its homeostatic set point was calculated by continuous two-phase linear regression. We hypothesized that, as drinking water salinity increases: (1) body water increases in concentration before it decreases in volume and (2) that regulating variables that help determine homeostatically set values (plasma hormone concentrations and water flux) deviate from values of freshwater ducks at lower drinking water salinities than the variables they regulate (Osm(pl), hematocrit, TBW). Osm(pl) was the first variable for which we could calculate a deviation from its homeostatically controlled value. It increases at much lower drinking water salinity than that at which TBW decreases, supporting our first hypothesis, but not our second hypothesis. We further hypothesized that, because the concentration of Pekin duck salt gland secretion is only slightly higher than that of their drinking water, they increase water flux (drinking) as salinity of drinking water increases, until the latter exceeds the secretion concentration and then they drink less. There was no change in water flux until it decreases when TBW decreases, 329 mM NaCl and 335 mM NaCl, respectively. The results do not support our hypothesis that Pekin ducks increase drinking as the salinity of their drinking water increases, but do indicate that, at tolerable salinities, Pekin ducks maintain body water volume while allowing body water osmolality to increase. At higher salinities, ducks decrease drinking and use body water to get rid of the excess salt.

Toxicant- and response-specific comparisons of statistical methods for estimating effective concentrations.

Standard U.S. Environmental Protection Agency (U.S. EPA) statistical analyses of whole effluent toxicity tests involve the estimation of the concentration associated with a specified level of inhibition relative to control responses. Current U.S. EPA estimation methods (linear interpolation or probit-based methods) are compared to a recently developed parametric regression-based estimator, the relative inhibition concentration estimator RIp. The RIp estimation technique, with level of inhibition p = 25%, is applied to a series of chronic toxicity test data from a U.S. EPA Region 9 database of reference toxicity tests. Tests on marine species are conducted with one reference toxicant, while the freshwater tests are conducted with several reference toxicants. While the U.S. EPA estimators and the RIp estimator are highly correlated for red abalone larval shell development, the degree of correlation for fathead minnow responses varies with reference toxicant tested. The strength of the relationship between the RIp and the standard U.S. EPA estimators varies as a function of the reference toxicant. Correlations range between 0.67 and 0.99. For all biological responses included in this evaluation (fathead minnow growth or survival and red abalone larval development), experiments occurred where the RIp is estimable, while the standard U.S. EPA estimators are not. Nonestimability of the standard EPA methods appears to be related, in part, to the failure of models to account for enhanced responses, such as a hormesis effect prior to toxicity being manifest. The ability to account for such enhanced responses is a strength of the RIp method. Finally, a variance component analysis suggests that lab-to-lab variability is relatively low for the red abalone but relatively high for the fathead minnow.

Development of a 950-gene DNA array for examining gene expression patterns in mouse testis.

BACKGROUND: Over the past five years, interest in and use of DNA array technology has increased dramatically, and there has been a surge in demand for different types of arrays. Although manufacturers offer a number of pre-made arrays, these are generally of utilitarian design and often cannot accommodate the specific requirements of focused research, such as a particular set of genes from a particular tissue. We found that suppliers did not provide an array to suit our particular interest in testicular toxicology, and therefore elected to design and produce our own. RESULTS: We describe the procedures used by members of the US Environmental Protection Agency MicroArray Consortium (EPAMAC) to produce a mouse testis expression array on both filter and glass-slide formats. The approaches used in the selection and assembly of a pertinent, nonredundant list of testis-expressed genes are detailed. Hybridization of the filter arrays with normal and bromochloroacetic acid-treated mouse testicular RNAs demonstrated that all the selected genes on the array were expressed in mouse testes. CONCLUSION: We have assembled two lists of mouse (950) and human (960) genes expressed in the mouse and/or human adult testis, essentially all of which are available as sequence-verified clones from public sources. Of these, 764 are homologous and will therefore enable close comparison of gene expression between murine models and human clinical testicular samples.

SHIP's C-terminus is essential for its hydrolysis of PIP3 and inhibition of mast cell degranulation.

The SH2-containing inositol-5'-phosphatase, SHIP, restrains bone marrow-derived mast cell (BMMC) degranulation, at least in part, by hydrolyzing phosphatidylinositol (PI)-3-kinase generated PI-3,4,5-P(3) (PIP3) to PI-3,4-P(2). To determine which domains within SHIP influence its ability to hydrolyze PIP3, bone marrow from SHIP(-/-) mice was retrovirally infected with various SHIP constructs. Introduction of wild-type SHIP into SHIP(-/-) BMMCs reverted the Steel factor (SF)-induced increases in PIP3, calcium entry, and degranulation to those observed in SHIP(+/+) BMMCs. A 5'-phosphatase dead SHIP, however, could not revert the SHIP(-/-) response, whereas a SHIP mutant in which the 2 NPXY motifs were converted to NPXFs (2NPXF) could partially revert the SHIP(-/-) response. SF stimulation of BMMCs expressing the 2NPXF, which could not bind Shc, led to the same level of mitogen-activated protein kinase (MAPK) phosphorylation as that seen in BMMCs expressing the other constructs. Surprisingly, C-terminally truncated forms of SHIP, lacking different amounts of the proline rich C-terminus, could not revert the SHIP(-/-) response at all. These results suggest that the C-terminus plays a critical role in enabling SHIP to hydrolyze PIP(3) and inhibit BMMC degranulation.

Effects of a weaning protocol on ventilated pediatric intensive care unit (PICU) patients.

As part of a learning collaborative sponsored by the Center for the Evaluative Clinical Sciences (CECS) at Dartmouth College, a multidisciplinary pediatric intensive care unit (PICU) group began meeting in 1997 to evaluate potential performance improvement (PI) opportunities. A reduction in mechanical ventilation (MV) hours was the initial team focus. The multidisciplinary team developed and implemented protocols and physician order sets outlining care for MV weaning, neuromuscular blockade/therapeutic paralyzation, and enteral feedings. Since the initiation of our protocols in July 1997, we have significantly reduced the number of hours our PICU patients receive MV.

Morphological and pathological effects of cadmium ingestion on Pekin ducks exposed to saline.

This study examined the effects of simultaneous exposure to saline and cadmium (Cd) on organ mass and histology of a bird with salt glands, the Pekin duck, Anas platyrhynchos. Three mixed-sex groups, each containing 6 birds, ate duck pellets containing 0, 50, or 300 microg Cd/g, respectively, for 4 1/2 mo and drank 300 mM NaCl. Only females on the high-Cd diet lost body mass. Ingestion of Cd reduced heart mass in females. There was increased mass of Harderian and salt glands in both sexes. Mass of kidneys and liver increased only in males, and the gut mass (also length) increased more in males. Cadmium ingestion also induced (1) inflammation of renal interstitium and degenerative tubular changes, (2) marked degenerative changes in testes, (3) increased heart water content, (4) decreased cytoplasmic volume of liver cells, (5) reduced proportion of basophilic granular cells in chromaffin tissue of the adrenal glands, and (6) in the ileum, increased heterophilia in the lamina propria and, only in females, the apoptosis to mitosis ratio in crypt cells of the epithelium. The ducks' outward appearance gave no indication that ingesting large amounts of cadmium for 4 1/2 mo produced deleterious effects, but the physiological consequences were profound. Both sexes had greatly reduced gonadal mass and the males produced no sperm. The higher dietary level greatly hypertrophied the liver, kidneys, and gut only in males. The cadmium-induced changes in organs, particularly in the gonads, kidneys, and adrenal glands, should greatly impair the health and reproductive capacity of these ducks.

Phemx, a novel mouse gene expressed in hematopoietic cells maps to the imprinted cluster on distal chromosome 7.

Phemx (Pan hematopoietic expression) is a novel murine gene expressed in developmentally regulated sites of hematopoiesis from early in embryogenesis through adulthood. Phemx is expressed in hematopoietic progenitors and mature cells of the three main hematopoietic lineages. Conceptual translation of the murine Phemx cDNA predicts a 25-kDa polypeptide with four hydrophobic regions and several potential phosphorylation sites, suggestive of a transmembrane protein involved in cell signaling. The PHEMX protein is structurally similar to tetraspanin CD81 (TAPA-1), a transmembrane protein involved in leukocyte activation, adhesion, and proliferation. Phemx maps to the distal region of chromosome 7, a segment of the mouse genome that contains a cluster of genes that exhibit genomic imprinting. However, imprinting analysis of Phemx at the whole organ level shows that it is biallelically expressed, suggesting that mechanisms leading to monoallelic expression are not imposed at this locus. The human PHEMX ortholog is specifically expressed in hematopoietic organs and tissues and, in contrast to murine Phemx, undergoes alternative splicing. The unique mode and range of Phemx expression suggest that it plays a role in hematopoietic cell function.

Thapsigargin-induced degranulation of mast cells is dependent on transient activation of phosphatidylinositol-3 kinase.

Thapsigargin, which elevates cytosolic calcium levels by inhibiting the sarcoplasmic/endoplasmic reticulum calcium-dependent ATPase, was tested for its ability to degranulate bone marrow-derived mast cells (BMMCs) from src homology 2-containing inositol phosphatase +/+ (SHIP+/+) and SHIP-/- mice. As was found previously with steel factor, thapsigargin stimulated far more degranulation in SHIP-/- than in SHIP+/+ BMMCs, and this was blocked with the phosphatidylinositol-3 (PI-3) kinase inhibitors, LY294002 and wortmannin. In contrast to steel factor, however, this heightened degranulation of SHIP-/- BMMCs was not due to a greater calcium influx into these cells, nor was the thapsigargin-induced calcium influx inhibited by LY294002, suggesting that the heightened thapsigargin-induced degranulation of SHIP-/- BMMCs was due to a PI-3 kinase-regulated step distinct from that regulating calcium entry. An investigation of thapsigargin-stimulated pathways in both cell types revealed that MAPK was heavily but equally phosphorylated. Interestingly, the protein kinase C inhibitor, bisindolylmaleimide (compound 3), totally blocked thapsigargin-induced degranulation in both SHIP+/+ and SHIP-/- BMMCs. As well, thapsigargin stimulated a PI-3 kinase-dependent, transient activation of protein kinase B, and this activation was far greater in SHIP-/- than in SHIP+/+ BMMCs. Consistent with this, thapsigargin was found to be a potent survival factor, following cytokine withdrawal, for both cell types and was more potent with SHIP-/- cells. These studies have both identified an additional PI-3 kinase-dependent step within the mast cell degranulation process, possibly involving 3-phosphoinositide-dependent protein kinase-1 and a diacylglycerol-independent protein kinase C isoform, and shown that the tumor-promoting activity of thapsigargin may be due to its activation of protein kinase B and subsequent promotion of cell survival.

Classifying reasons for hospital readmissions.

Readmissions are a key measurement tool in today's outcomes-focused health care environment. Monitoring the volume of readmissions is a straightforward process in light of the database resources available to care providers. Examining and reporting on the actual reasons for readmissions provides opportunities for improvement specific to the needs of a patient population. The readmission coding tool used at the Medical University of South Carolina demonstrates both the ability to assess the causes for patients returning to our institution within thirty days of discharge and the opportunity to correct problems in specific service areas with regard to discharge planning.

Effect of cadmium on Pekin duck total body water, water flux, renal filtration, and salt gland function.

The following hypotheses were examined using Pekin ducks (Anas platyrhynchos) as a model for marine ducks: cadmium (Cd) intake affects (1) salt gland and/or kidney function of ducks and (2) osmoregulation differently in male and female ducks. Birds were fed 0, 50, or 300 microg Cd/g food. They were gradually acclimated to 450 mM NaCl and then drank 300 mM NaCl for 3 mo while salt gland secretion (SGS), glomerular filtration rate (GFR), total body water (TBW), and water flux (WF) were measured in ducks eating control and high-Cd diets. Cadmium ingestion did not markedly affect body mass, but significantly enlarged the salt glands and kidneys. Enhancement of kidney mass was greater in males. Cadmium ingestion did not affect TBW or WF, but tended to increase interstitial fluid space at the expense of intracellular fluid. Sex did not affect TBW, but males had greater WF. Birds that ate Cd diets, especially the higher Cd diet, exhibited renal tubular damage and lower GFR. Ducks that ate Cd had lower plasma sodium concentration and osmolality and, to activate SGS, required longer infusion of NaCl and larger increments