|
| ||
|
|
||
Cell Volume (cell + volume)
Kinds of Cell Volume Terms modified by Cell Volume Selected AbstractsControl of Cell Volume in Skeletal MuscleBIOLOGICAL REVIEWS, Issue 1 2009Juliet A. Usher-Smith Abstract Regulation of cell volume is a fundamental property of all animal cells and is of particular importance in skeletal muscle where exercise is associated with a wide range of cellular changes that would be expected to influence cell volume. These complex electrical, metabolic and osmotic changes, however, make rigorous study of the consequences of individual factors on muscle volume difficult despite their likely importance during exercise. Recent charge-difference modelling of cell volume distinguishes three major aspects to processes underlying cell volume control: (i) determination by intracellular impermeant solute; (ii) maintenance by metabolically dependent processes directly balancing passive solute and water fluxes that would otherwise cause cell swelling under the influence of intracellular membrane-impermeant solutes; and (iii) volume regulation often involving reversible short-term transmembrane solute transport processes correcting cell volumes towards their normal baselines in response to imposed discrete perturbations. This review covers, in turn, the main predictions from such quantitative analysis and the experimental consequences of comparable alterations in extracellular pH, lactate concentration, membrane potential and extracellular tonicity. The effects of such alterations in the extracellular environment in resting amphibian muscles are then used to reproduce the intracellular changes that occur in each case in exercising muscle. The relative contributions of these various factors to the control of cell volume in resting and exercising skeletal muscle are thus described. [source] Ammonia impairs neutrophil phagocytic function in liver disease,HEPATOLOGY, Issue 4 2008Debbie L. Shawcross Hyperammonemia is a feature of liver failure, which is associated with increased risk of infection. The aims of the present study were to determine in vitro, in rats fed an ammoniagenic diet and in patients with cirrhosis, whether induction of hyperammonemia results in neutrophil dysfunction. As hyperammonemia produces cell swelling, we explored the role of the osmoregulating, p38 mitogen-activated protein kinase (p38MAPK) pathway in mediating this neutrophil dysfunction. Neutrophils were isolated from blood of healthy volunteers and incubated with either 75 ,M ammonia or phosphate-buffered saline. Both groups were studied under hyponatremic conditions and/or with the addition of p38MAPK modulators. Neutrophil phagocytosis was measured in naive rats and rats fed an ammoniagenic diet and in patients with stable cirrhosis given placebo (n = 8) or an amino acid solution inducing hyperammonemia (n = 8). Cell volume and phagocytosis was analyzed by fluorescent-activated cell sorting using fluorescein isothiocyanate,labeled E. coli. p38MAPK phosphorylation was measured by western blotting. In healthy neutrophils incubated with ammonia and in rats fed an ammoniagenic diet, neutrophils showed evidence of swelling, impaired phagocytosis, and increased spontaneous oxidative burst compared to controls. Phagocytosis was significantly impaired in patients with induced hyperammonemia compared to placebo. The effects of hyperammonemia and hyponatremia were synergistic. The p38MAPK intracellular signaling pathways were activated in healthy neutrophils exposed to ammonia in association with increased burst activity. Neutrophil phagocytic dysfunction was abrogated by the addition of a p38MAPK agonist. Conclusion: Ammonia produces neutrophil swelling and impairs neutrophil phagocytosis. The p38MAPK intracellular signaling pathway has been shown to be important in mediating the ammonia-induced neutrophil dysfunction. (HEPATOLOGY 2008.) [source] DIEL VARIATIONS IN OPTICAL PROPERTIES OF IMANTONIA ROTUNDA (HAPTOPHYCEAE) AND THALASSIOSIRA PSEUDONANA (BACILLARIOPHYCEAE) EXPOSED TO DIFFERENT IRRADIANCE LEVELS,JOURNAL OF PHYCOLOGY, Issue 3 2008Sébastien Mas Diel variations of cellular optical properties were examined for cultures of the haptophyte Imantonia rotunda N. Reynolds and the diatom Thalassiosira pseudonana (Hust.) Hasle et Heimdal grown under a 14:10 light:dark (L:D) cycle and transferred from 100 ,mol photons · m,2 · s,1 to higher irradiances of 250 and 500 ,mol photons · m,2 · s,1. Cell volume and abundance, phytoplankton absorption coefficients, flow-cytometric light scattering and chl fluorescence, and pigment composition were measured every 2 h over a 24 h period. Results showed that cell division was more synchronous for I. rotunda than for T. pseudonana. Several variables exhibited diel variability with an amplitude >100%, notably mean cell volume for the haptophyte and photoprotective carotenoids for both species, while optical properties such as flow-cytometric scattering and chl a,specific phytoplankton absorption generally showed <50% diel variability. Increased irradiance induced changes in pigments (both species) and mean cell volume (for the diatom) and amplified diel variability for most variables. This increase in amplitude is larger for pigments (factor of 2 or more, notably for cellular photoprotective carotenoid content in I. rotunda and for photosynthetic pigments in T. pseudonana) than for optical properties (a factor of 1.5 for chl a,specific absorption, at 440 nm, in I. rotunda and a factor of 2 for the absorption cross-section and the chl a,specific scattering in T. pseudonana). Consequently, diel changes in optical properties and pigmentation associated with the L:D cycle and amplified by concurrent changes in irradiance likely contribute significantly to the variability in optical properties observed in biooptical field studies. [source] Cell volume and rate of proliferation, but not protein expression pattern, distinguish pup/intimal smooth muscle cells from subcultured adult smooth muscle cellsCELL PROLIFERATION, Issue 5 2001E. McKilligin Smooth muscle cells from neonatal rats and from injured blood vessels grow with a characteristic cobblestone morphology that distinguishes them from adult smooth muscle cells. This has led to the proposition that there are two distinct types of smooth muscle cells with different proliferative capacity. Here we systematically compare the properties of subcultured adult smooth muscle cells in culture and clonal lines of cobblestone smooth muscle cells from both neonatal rats and injured vessels. The cobblestone smooth muscle cells have a significantly smaller average cell volume, estimated using two different flow cytometry measurements. However, the two types of smooth muscle cells have indistinguishable protein expression patterns when the levels of more than 20 different proteins (including cytoskeletal proteins, matrix proteins, cytokines, cytokine receptors, adhesion molecules and enzymes) are measured by quantitative immunofluorescence. Furthermore, in contrast to previous observations, we demonstrate that both types of smooth muscle cells secrete a powerful mitogenic activity. The higher cell density achieved by the cobblestone smooth muscle cells in culture was responsible for the earlier reports that this mitogenic activity was secreted only by cobblestone smooth muscle cells. We conclude that many of the differences seen between cobblestone smooth muscle cells and adult smooth muscle cells in vitro (proliferation rate, morphology, protein expression pattern, secretion of mitogenic activity) could be attributable to a stable difference in the median cell volume of the cultures. [source] Investigation of prolonged neonatal jaundiceACTA PAEDIATRICA, Issue 6 2000S Hannam Jaundice persisting beyond 14 d of age (prolonged jaundice) can be a sign of serious underlying liver disease. Protocols for investigating prolonged jaundice vary in complexity and the yield from screening has not been assessed. In order to address these issues, we carried out a prospective study of term infants referred to our neonatal unit with prolonged jaundice over an 18 mo period. Infants were examined by a paediatrician and had the following investigations: a total and conjugated serum bilirubin, liver function tests, full blood count, packed cell volume, group and Coombs' test, thyroid function tests, glucose-6-phosphate dehydrogenase levels and urine for culture. One-hundred-and-fifty-four infants were referred with prolonged jaundice out of 7139 live births during the study period. Nine infants were referred to other paediatric specialties. One infant had a conjugated hyperbilirubinaemia, giving an incidence of conjugated hyperbilirubinaemia of 0.14 per 1000 live births. Diagnoses included: giant cell hepatitis (n= 1), hepatoblastoma (n= 1), trisomy 9p (n= 1), urinary tract infections (n= 2), glucose-6-phosphate dehydrogenase deficiency (n= 3) and failure to regain birthweight (n= 1). Conclusions: In conclusion, a large number of infants referred to hospital for prolonged jaundice screening had detectable problems. The number of investigations may safely be reduced to: a total and conjugated bilirubin, packed cell volume, glucose-6-phosphate dehydrogenase level (where appropriate), a urine for culture and inspection of a recent stool sample for bile pigmentation. Clinical examination by a paediatrician has a vital role in the screening process. [source] The Effect of Erythropoietin on Exercise Capacity, Left Ventricular Remodeling, Pressure-Volume Relationships, and Quality of Life in Older Patients With Anemia and Heart Failure With Preserved Ejection FractionCONGESTIVE HEART FAILURE, Issue 3 2010Rose S. Cohen MD A prospective, open-label, 3-month study was conducted to evaluate the feasibility and short-term clinical effect of subcutaneous erythropoietin injections in patients with anemia and heart failure with preserved ejection fraction (ejection fraction, 55%±2%). Using a dose-adjusted algorithm to effect a rate of rise in hemoglobin not to exceed 0.4 g/dL,/wk, hemoglobin (10.8±0.3 to 12.2±0.3 g/dL) and red blood cell volume (1187±55 to 1333±38 mL) increased with an average weekly dose of 3926 units. Functional measures increased from baseline (6-minute walk test [289±24 to 331±22 m], exercise time [432±62 to 571±51 s], and peak oxygen consumption [8.2±0.7 to 9.4±0.9 mL/kg/min], all P<.05). End-diastolic volume declined significantly (8% volumetric decrease, 108±3 to 100±3 mL, P =.03), but there were no significant changes in left ventricular mass or estimated left ventricular end-diastolic pressure. Pressure-volume analysis demonstrated a reduction in ventricular capacitance at an end-diastolic pressure of 30 mm Hg without significant changes in contractile state. Congest Heart Fail. 2010;16:96,103. © 2009 Wiley Periodicals, Inc. [source] A role for the volume regulated anion channel in volume regulation in the murine CNS cell line, CADACTA PHYSIOLOGICA, Issue 2 2010V. L. Harvey Abstract Aim:, The role of the volume regulated anion channel (VRAC) in a model CNS neuronal cell line, CAD, was investigated. Methods:, Changes in cell volume following hypotonic challenges were measured using a video-imaging technique. The effect of the Cl, channel antagonists tamoxifen (10 ,m) and 4,4,-diisothiocyanatostilbene-2,2,-disulphonic acid (DIDS; 100 ,m) on regulatory volume decrease (RVD) were measured. The whole-cell voltage-clamp technique was used to characterize IClswell, the current underlying the VRAC. Results:, Using the video-imaging technique, CAD cells were found to swell and subsequently exhibit RVD when subjected to a sustained hypotonic challenge from 300 mOsmol kg,1 H2O to 210 mOsmol kg,1 H2O. In the presence of tamoxifen (10 ,m) or DIDS (100 ,m) RVD was abolished, suggesting a role for the VRAC. A hypotonic solution (230 mOsmol kg,1 H2O) evoked IClswell, an outwardly rectifying current displaying time-independent activation, which reversed upon return to isotonic conditions. The reversal potential (Erev) for IClswell was ,14.7 ± 1.4 mV, similar to the theoretical Erev for a selective Cl, conductance. IClswell was inhibited in the presence of DIDS (100 ,m) and tamoxifen (10 ,m), the DIDS inhibition being voltage dependent. Conclusions:, Osmotic swelling elicits an outwardly rectifying Cl, conductance in CAD cells. The IClswell observed in these cells is similar to that observed in other cells, and is likely to provide a pathway for the loss of Cl, which leads to water loss and RVD. As ischaemia, brain trauma, hypoxia and other brain pathologies can cause cell swelling, CAD cells represent a model cell line for the study of neuronal cell volume regulation. [source] Preparation and characterization of powders and crystals of Vn-xTixO2n-1 Magneli oxidesCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10-11 2005D. Calestani Abstract Vn-xTixO2n-1 Magnéli phases have been synthesized under vacuum in powder form (n = 4, 0 , x , 0.4) and crystals (n = 4 and 5, x = 0.5 and 1.4, respectively), grown by chemical vapour transport in closed ampoules. TeCl4 and NH4Cl were used as transporting agents. Needle-shaped crystals as long as 200-300 micrometers or 2-3 mm were obtained when in presence of NH4Cl or TeCl4, respectively. The powder and crystal structures were examined by X-ray diffraction and the transport and magnetic characteristics were measured.. The powders resulted to be single-phase and the relevant composition was assumed to be equal to the nominal one. The overall stoichiometry of compounds, n, was determined from single crystal X-ray diffraction data. The Ti content, x, was deduced from the elementary cell volume, by applying the Végard law. Crystals were mainly untwinned and of good quality. The elementary cell of both, powders and crystals, was triclinic (P-1) and did not change with doping. DC electrical resistivity of the crystals was measured in a four-points (van der Pauw) configuration. DC magnetic susceptibility of the powders was measured in a SQUID magnetometer. The Ti doping was found to progressively smooth and finally to suppress the magnetic transitions occurring in the V4O7. The metal-insulator transitions observed in V4O7 and V5O9, at around 235 and 125 K respectively, were not observed in the doped crystals, thus indicating some significant change of the electronic structure of the V oxides. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Na+/H+ exchangers and the regulation of volumeACTA PHYSIOLOGICA, Issue 1-2 2006R. T. Alexander Abstract The regulation of volume is fundamental to life. There exist numerous conditions that can produce perturbations of cell volume. The cell has developed mechanisms to directly counteract these perturbations so as to maintain its physiological volume. Directed influx of the major extracellular cation, sodium, serves to counteract a decreased cell volume through the subsequent osmotically coupled movement of water to the intracellular space. This process, termed regulatory volume increase is often mediated by the ubiquitous sodium/hydrogen ion exchanger, NHE1. Similarly, the maintenance of intravascular volume is essential for the maintenance of blood pressure and consequently the proper perfusion of vital organs. Numerous mechanisms exist to counterbalance alterations in intravascular volume, not the least of which is the renal absorption of sodium filtered at the glomerulus. Two-thirds of filtered sodium and water are absorbed in the renal proximal tubule, a mechanism that intimately involves the apical sodium/hydrogen ion exchanger, NHE3. This isoform is fundamental to the maintenance and regulation of intravascular volume and blood pressure. In this article, the effects of cell volume on the activity of these different isoforms, NHE1 and NHE3, will be described and the consequences of their activity on intracellular and intravascular volume will be explored. [source] Compaction of cell shape occurs before decrease of elasticity in CHO-K1 cells treated with actin cytoskeleton disrupting drug cytochalasin DCYTOSKELETON, Issue 4 2009Christian Schulze Abstract The actin filaments of the cytoskeleton form a highly dynamic polymer scaffold which is actively involved in many essential mechanisms such as cell migration, transport, mitosis, and mechanosensitivity. We treated CHO-K1 cells with different concentrations of the actin cytoskeleton disrupting drug cytochalasin D. Then investigating the cells' elastic behaviour by scanning force microscopy-based rheology we confirmed for high cytochalasin D concentrations (,1.5 ,M) a significant decrease of mechanical stability. At lower concentrations we measured no significant softening, but flattening and a horizontal contraction was observable even at low concentrations (,0.3 ,M) of cytochalasin D. The observed changes in cell shape resulted in a lower cell volume, showing that there is compensation by volume for small decreases in cytoskeletal strength resulting from reduced numbers or lengths of actin filaments. These results suggest that the characteristic functions defining a cell's mechanical stability such as mechanosensitivity can be maintained via small changes in cell volume in order to counter fluctuations in cytoskeletal composition. Cell Motil. Cytoskeleton 2009. © 2009 Wiley-Liss, Inc. [source] Cleavage-like cell division and explosive increase in cell number of neonatal gonocytesDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 1 2004Yasuhiro Sakai Based on previous conventional quantitative observations of rat testes, it was proposed that large numbers of gonocytes degenerate after birth and this notion was widely accepted. However, many studies show that neonatal gonocytes display high levels of mitotic activity. In order to resolve the apparent contradiction of increased mitotic activity in gonocytes despite a decrease in their numbers at the neonate stage, quantitative analysis using a marker of suitably higher resolution is required. It has been shown that the vasa protein could be used as a marker of germ cells. In this study, quantitative changes in gonocytes were re-examined using a germ-cell-specific marker in order to delineate more clearly the process of development from gonocytes to spermatogonia after birth. The vasa -positive cells, which correspond to gonocytes and spermatogonia, increased exponentially after birth. This observation suggests that all gonocyte divide actively after birth and do not degenerate as previously believed. Surprisingly, the cell volume of gonocytes decreased during their division. The largest population size was 2000,4000 µ3 at day 2, 1000,2000 µ3 at day 4 and 500,1000 µ3 at day 6. This finding suggests that gonocytes divide in a similar way to cleavage, which can be considered a special mode of fertilized eggs. Judging from the growth of seminiferous tubules and the degree of volume reduction, 60% of the contribution rate is estimated to be due to ordinal cell growth, and 40% due to volume reduction as in cleavage of a fertilized egg. This unique cleavage-like division may contribute to the supply of large numbers of spermatogonia. [source] MMP-2 contributes to the development of the mouse ventral prostate by impacting epithelial growth and morphogenesisDEVELOPMENTAL DYNAMICS, Issue 9 2010Alexandre Bruni-Cardoso Abstract Epithelial growth, branching, and canalization are important morphogenetic events of the rodent ventral prostate (VP) that take place during the first postnatal week. In this study, we evaluated the effect of knocking out MMP-2 (MMP-2,/,), by examining developmental and structural aspects of the VP in MMP-2,/, mice. Neonate (day 6) MMP-2,/, mice showed fewer epithelial tips, a lower epithelial cell proliferation rate, and also reticulin fiber accumulation. The VP of adult MMP-2,/, mice showed lower relative weight, smaller epithelial and smooth-muscle cell volume, and a larger amount of thicker reticulin fibers. No differences in cell proliferation or apoptotic index were noted between adult MMP-2,/, and wild-type mice. MMP-9 was found in the adult MMP-2,/,, but not in the wild-type. In conclusion, MMP-2 function is essential for the epithelial morphogenesis of the mouse VP, and expression of MMP-9 is not sufficient for acquisition of the normal adult histology. Developmental Dynamics 239:2386,2392, 2010. © 2010 Wiley-Liss, Inc. [source] Bacterial traits, organism mass, and numerical abundance in the detrital soil food web of Dutch agricultural grasslandsECOLOGY LETTERS, Issue 1 2005Christian Mulder Abstract This paper compares responses to environmental stress of the ecophysiological traits of organisms in the detrital soil food webs of grasslands in the Netherlands, using the relationship between average body mass M and numerical abundance N. The microbial biomass and biodiversity of belowground fauna were measured in 110 grasslands on sand, 85 of them farmed under organic, conventional and intensive management. Bacterial cell volume and abundance and electrophoretic DNA bands as well as bacterial activity in the form of either metabolic quotient (qCO2) or microbial quotient (Cmic/Corg) predicted the response of microorganisms to stress. For soil fauna, the logarithm of body mass log(M) was approximately linearly related to the logarithm of numerical abundance log(N) with slope near ,1, and the regression slope and the proportion of predatory species were lower in intensive agroecosystems (more reduced substrates with higher energy content). Linear regression of log(N) on log(M) had slope not far from ,3/4. The approach to monitoring data illustrated in this paper could be useful in assessing land-use quality. [source] Hematotoxic and hepatotoxic effects of dichlorvos at sublethal dosages in ratsENVIRONMENTAL TOXICOLOGY, Issue 2 2009Ismail Celik Abstract The present study was designed to understand the effects of sublethal concentrations of dichlorvos (DIC) on hematological constituent [red blood corpuscles, white blood corpuscles (WBC), mean cell volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, platelet counts, hemoglobin and hematocrite levels] and serum damage marker enzymes (aspartate aminotransferase, alanin aminotransferase, alkaline phosphatase, and lactate dehydrogenase) in rats at subacute period under laboratory conditions. DIC at dosages of 5 and 10 ppm was administered orally to six male rats ad libitum during the tests for 4 weeks consecutively. According to the results, DIC treatments increased significantly the levels of serum marker enzyme activities, whereas they did not change hematologic constituent except for WBC number treated with both dosages of DIC. The observations presented led us to conclude that the administrations of subacute DIC induced the levels of damage marker enzymes and leukocytosis. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009. [source] Influence of dietary 2,4,6-trinitrotoluene exposure in the northern bobwhite (Colinus virginianus)ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2002Robert M. Gogal Jr. Abstract The risk to wildlife from exposure to the explosive, 2,4,6-trinitrotoluene (TNT) has been a concern at numerous military installations where it has been found in the soil. To date, no published data are available describing effects of TNT exposure in an avian species. Subchronic dietary exposure to TNT was therefore evaluated in a species of management concern at military installations, the northern bobwhite (Colinus virginianus). Adult male and female quail (n = 5/sex/dose) were given commercial feed containing 3,000, 1,500, 750, and 100 mg/kg TNT for 90 d following the determination of an acute lethal dose and a 14-d range finding study. Dietary TNT intake caused a dose-dependent decrease in total red blood cell counts, packed cell volume, total plasma protein, blood prolymphocytes, and blood lymphocytes. An increased trend in late apoptotic/necrotic blood leukocytic cells was also observed in TNT-exposed birds, as was hemosiderosis in the liver. With the exception of hemosiderosis, these trends were statistically significant yet of questionable biological significance. Since treatment-related responses in this preliminary study were variable, a conservative interpretation is suggested. However, since these treatments had concentrations that were a log-fold or more than doses in similar studies using mammals, these data suggest that northern bobwhite are less sensitive to oral exposures of TNT than mammals. [source] The workload of riding-school horses during jumpingEQUINE VETERINARY JOURNAL, Issue S36 2006M. M. SLOET Van OLDRUITENBORGH-OOSTERBAAN Summary Reasons for performing the study: As there are no reports on the real workload of horses that jump fences, this study was undertaken in riding-school horses. Objective: To compare the workload of horses jumping a course of fences with that of horses cantering over the same course at the same average speed without jumping fences. The workload variables included heart rate (HR), packed cell volume (PCV), acid-base balance (venous pH, pCO2, HCO3,) and blood lactate (LA), glucose, total protein and electrolyte concentrations. Methods: Eight healthy riding-school horses performed test A (a course of approximately 700 m with 12 jumps from 0.8-1.0 m high at an average speed of approximately 350 m/min) and test B (same course at the same speed, but without the rails) in a crossover study with at least 4 h between the 2 tests. Before each test the horses were fitted with a heart rate meter (Polar Electro)1. Blood samples were taken from the jugular vein at rest prior to the test, after warm-up before starting the course, immediately after the course and after recovery. All samples were analysed immediately. Results: The mean ± s.d maximal HR (beats/min) during the course (184 ± 17 and 156 ± 21, respectively) and the mean HR after recovery (75 ± 6 and 63 ± 7, respectively) were significantly higher in test A compared to test B (P=0.001 and P=0.007 respectively). The mean LA concentrations after the course and after recovery (mmol/1) were significantly higher in test A (3.6 ± 2.7 and 1.0 ± 0.9, respectively) compared to test B (0.9 ± 0.5 and 0.3 ± 0.1, respectively), (P=0.016 and P = 0.048 respectively). The mean PCV (1/1) after the course and after recovery was also significantly different between tests A (0.48 ± 0.04 and 0.39 ± 0.03, respectively) and B (0.42 ± 0.04 and 0.36 ± 0.03, respectively) (P<0.01). The mean pH and the mean HCO3, (mmol/1) after the course were significantly lower in test A (7.40 ± 0.04 and 28.9 ± 1.4, respectively) compared to test B (7.45 ± 0.03 and 30.4 ± 2.3, respectively) (P<0.05). Conclusions: This study indicates that in riding-school horses jumping fences, even at a low level competition, provokes a significant workload compared to cantering the same distance and speed without fences. Potential relevance: This study makes it clear that the extra workload of jumping fences should be taken into account in the training programmes of jumping horses. Further research with more experienced horses jumping higher fences will reveal the workload for top-level jumping horses. [source] Use of advanced red blood cell and reticulocyte indices improves the accuracy in diagnosing iron deficiency in pregnant women at termEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 6 2007Mari Ervasti Abstract Objectives:, Detection of iron deficiency during pregnancy with hemoglobin (Hb) and serum measurements is insignificant as the measurements may be affected by e.g. hemodilution or accelerated erythropoiesis. This study tests whether cell indices will give a more reliable measure of iron deficiency in pregnant women at term. Methods:, The population was 202 pregnant women. Using the ADVIA 120 hematology system, Hb, mean cell volume (MCV), percentage of hypochromic red blood cells (%HYPOm) and reticulocytes (%HYPOr), and cellular hemoglobin in reticulocytes (CHr) were tested. Additionally, transferrin saturation (TfSat), ferritin, and transferrin receptor (TfR) were analyzed. Receiver operating characteristic (ROC) curves and area under the ROC curves (AUC) were used as statistical methods. Results:, When TfSat (,11%) was used as the reference test for iron deficiency, %HYPOm and CHr had a sensitivity of 58.1% and 80.7%, while the specificities were 82.6% and 71.3%, respectively. Additionally, the AUC values were %HYPOr 0.80, CHr 0.79, ferritin 0.77, %HYPOm 0.75, TfR 0.67, MCV 0.63 and Hb 0.64. The results provided by the cell indices alone (%HYPOm or CHr) were in good agreement with the results based on the usage of a combination of three commonly used tests (Hb, MCV, ferritin). Conclusions:, This study suggests that the most practical way to diagnose iron deficiency in pregnant women at term is to use cell indices such as CHr and %HYPOm provided by the automated hematological analyzer. Further studies are needed to determine the usefulness of the cell indices in diagnosing iron deficiency longitudinally during the course of pregnancy. [source] Normal ranges for packed cell volume and hemoglobin concentration in adults: relevance to "apparent polycythemia"EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 1 2001TC Pearson [source] AQP4 expression in striatal primary cultures is regulated by dopamine , implications for proliferation of astrocytesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2008Eva Küppers Abstract Proliferation of astrocytes plays an essential role during ontogeny and in the adult brain, where it occurs following trauma and in inflammation and neurodegenerative diseases as well as in normal, healthy mammals. The cellular mechanisms underlying glial proliferation remain poorly understood. As dopamine is known to modulate proliferation in different cell populations, we investigated the effects of dopamine on the proliferation of striatal astrocytes in vitro. We found that dopamine reduced proliferation. As proliferation involves, among other things, a change in cell volume, which normally comes with water movement across the membrane, water channels might represent a molecular target of the dopamine effect. Therefore we studied the effect of dopamine on aquaporin 4 (AQP4) expression, the main aquaporin subtype expressed in glial cells, and observed a down-regulation of the AQP4-M23 isoform. This down-regulation was the cause of the dopamine-induced decrease in proliferation as knockdown of AQP4 using siRNA techniques mimicked the effects of dopamine on proliferation. Furthermore, stimulation of glial proliferation by basic fibroblast growth factor was also abolished by knocking down AQP4. In addition, blocking of AQP4 with 10 ,m tetraethylammonium inhibited osmotically induced cell swelling and stimulation of glial cell proliferation by basic fibroblast growth factor. These results demonstrate a clear-cut involvement of AQP4 in the regulation of proliferation and implicate that modulation of AQP4 could be used therapeutically in the treatment of neurodegenerative diseases as well as in the regulation of reactive astrogliosis by preventing or reducing the glia scar formation, thus improving regeneration following ischemia or other trauma. [source] Small-conductance Cl, channels contribute to volume regulation and phagocytosis in microgliaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2007Guillaume Ducharme Abstract The shape and volume of microglia (brain immune cells) change when they activate during brain inflammation and become migratory and phagocytic. Swollen rat microglia express a large Cl, current (IClswell), whose biophysical properties and functional roles are poorly understood and whose molecular identity is unknown. We constructed a fingerprint of useful biophysical properties for comparison with IClswell in other cell types and with cloned Cl, channels. The microglial IClswell was rapidly activated by cell swelling but not by voltage, and showed no time-dependence during voltage-clamp steps. Like IClswell in many cell types, the halide selectivity sequence was I, > Br, > Cl, > F,. However, it differed in lacking inactivation, even at +100 mV with high extracellular Mg2+, and in having a much lower single-channel conductance: 1,3 pS. Based on these fundamental differences, the microglia channel is apparently a different gene product than the more common intermediate-conductance IClswell. Microglia express several candidate genes, with relative mRNA expression levels of: CLIC1 > ClC3 > ICln , ClC2 > Best2 > Best1 , Best3 > Best4. Using a pharmacological toolbox, we show that all drugs that reduced the microglia current (NPPB, IAA-94, flufenamic acid and DIOA) increased the resting cell volume in isotonic solution and inhibited the regulatory volume decrease that followed cell swelling in hypotonic solution. Both channel blockers tested (NPPB and flufenamic acid) dose-dependently inhibited microglia phagocytosis of E. coli bacteria. Because IClswell is involved in microglia functions that involve shape and volume changes, it is potentially important for controlling their ability to migrate to damage sites and phagocytose dead cells and debris. [source] Application of stereology to dermatological researchEXPERIMENTAL DERMATOLOGY, Issue 12 2009Sřren Kamp Abstract:, Stereology is a set of mathematical and statistical tools to estimate three-dimensional (3-D) characteristics of objects from regular two-dimensional (2-D) sections. In medicine and biology, it can be used to estimate features such as cell volume, cell membrane surface area, total length of blood vessels per volume tissue and total number of cells. The unbiased quantification of these 3-D features allows for a better understanding of morphology in vivo compared with 2-D methods. This review provides an introduction to the field of stereology with specific emphasis on the application of stereology to dermatological research by supplying a short insight into the theoretical basis behind the technique and presenting previous dermatological studies in which stereology was an integral part. Both the theory supporting stereology and a practical approach in a dermatological setting are reviewed with the aim to provide the reader with the capability to better assess papers employing stereological estimators and to design stereological studies independently. [source] Molecular physiology of SLC4 anion exchangersEXPERIMENTAL PHYSIOLOGY, Issue 1 2006Seth L. Alper Plasmalemmal Cl,,HCO3, exchangers regulate intracellular pH and [Cl,] and cell volume. In polarized epithelial cells, they contribute also to transepithelial secretion and reabsorption of acid,base equivalents and of Cl,. Members of both the SLC4 and SLC26 mammalian gene families encode Na+ -independent Cl,,HCO3, exchangers. Human SLC4A1/AE1 mutations cause either the erythroid disorders spherocytic haemolytic anaemia or ovalocytosis, or distal renal tubular acidosis. SLC4A2/AE2 knockout mice die at weaning. Human SLC4A3/AE3 polymorphisms have been associated with seizure disorder. Although mammalian SLC4/AE polypeptides mediate only electroneutral Cl,,anion exchange, trout erythroid AE1 also promotes osmolyte transport and increased anion conductance. Mouse AE1 is required for DIDS-sensitive erythroid Cl, conductance, but definitive evidence for mediation of Cl, conductance is lacking. However, a single missense mutation allows AE1 to mediate both electrogenic SO42,,Cl, exchange or electroneutral, H+ -independent SO42,,SO42, exchange. In the Xenopus oocyte, the AE1 C-terminal cytoplasmic tail residues reported to bind carbonic anhydrase II are dispensable for Cl,,Cl, exchange, but required for Cl,,HCO3, exchange. AE2 is acutely and independently inhibited by intracellular and extracellular H+, and this regulation requires integrity of the most highly conserved sequence of the AE2 N-terminal cytoplasmic domain. Individual missense mutations within this and adjacent regions identify additional residues which acid-shift pHo sensitivity. These regions together are modelled to form contiguous surface patches on the AE2 cytoplasmic domain. In contrast, the N-terminal variant AE2c polypeptide exhibits an alkaline-shifted pHo sensitivity, as do certain transmembrane domain His mutants. AE2-mediated anion exchange is also stimulated by ammonium and by hypertonicity by a mechanism sensitive to inhibition by chelation of intracellular Ca2+ and by calmidazolium. This growing body of structure,function data, together with increased structural information, will advance mechanistic understanding of SLC4 anion exchangers. [source] Cell shrinkage evoked by Ca2+ -free solution in rat alveolar type II cells: Ca2+ regulation of Na+,H+ exchangeEXPERIMENTAL PHYSIOLOGY, Issue 2 2005Hitoshi Murao The effects of intracellular Ca2+ concentration, [Ca2+]i, on the volume of rat alveolar type II cells (AT-II cells) were examined. Perfusion with a Ca2+ -free solution induced shrinkage of the AT-II cell volume in the absence or presence of amiloride (1 ,m, an inhibitor of Na+ channels); however, it did not in the presence of 5-(N -methyl- N -isobutyl)-amiloride (MIA, an inhibitor of Na+,H+ exchange). MIA decreased the volume of AT-II cells. Inhibitors of Cl,,HCO3, exchange, 4,4,-diisothiocyanostilbene-2,2,-disulfonic acid (DIDS) and 4-acetamido-4,-isothiocyanatostilbene-2,2,-disulfonic acid (SITS) also decreased the volume of AT-II cells. This indicates that the cell shrinkage induced by a Ca2+ -free solution is caused by a decrease in NaCl influx via Na+,H+ exchange and Cl,,HCO3, exchange. Addition of ionomycin (1 ,m), in contrast, induced cell swelling when AT-II cells were pretreated with quinine and amiloride. This swelling of the AT-II cells is not detected in the presence of MIA. Intracellular pH (pHi) measurements demonstrated that the Ca2+ -free solution or MIA decreases pHi, and that ionomycin increases it. Ionomycin stimulated the pHi recovery after an acid loading (NH4+ pulse method), which was not noted in MIA-treated AT-II cells. Ionomycin increased [Ca2+]i in fura-2-loaded AT-II cells. In conclusion, the Na+,H+ exchange activities of AT-II cells, which maintain the volume and pHi, are regulated by [Ca2+]i. [source] Bumetanide, the Specific Inhibitor of Na+ -K+ -2Cl, Cotransport, Inhibits 1,,25-Dihydroxyvitamin D3 -Induced Osteoclastogenesis in a Mouse co-culture SystemEXPERIMENTAL PHYSIOLOGY, Issue 5 2003Hyun-A Lee The Na+ -K+ -2Cl, cotransporter (NKCC1) is responsible for ion transport across the secretory and absorptive epithelia, the regulation of cell volume, and possibly the modulation of cell growth and development. It has been reported that a variety of cells, including osteoblasts, contain this cotransporter. In this study, the physiological role of NKCC1 in osteoclastogenesis was exploited in a co-culture system. Bumetanide, a specific inhibitor of NKCC1, reduced the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells. In order to investigate the mechanism by which bumetanide inhibits osteoclastogenesis, the mRNA expressions of the receptor activator of nuclear factor (NF)-,B ligand (RANKL) and osteoprotegerin (OPG) were analysed by RT-PCR. Exposure of osteoblastic cells to a medium containing 1 µM bumetanide reduced RANKL mRNA expression induced by 10 nM 1,,25-dihydroxyvitamin D3 (1,,25(OH)2D3, in a dose-dependent manner. In addition, RANKL expression was also analysed with enzyme-linked immunosorbant assay (ELISA) using anti-RANKL antibody. The expression of RANKL was decreased with the increase of bumetanide concentration. In contrast, the expression of OPG mRNA, a novel tumour necrosis factor (TNF) receptor family member was increased in the presence of bumetanide. These results imply that bumetanide inhibits osteoclast differentiation by reducing the RANKL/OPG ratio in osteoblastic cells. However, no significant difference in M-CSF mRNA expression was observed when bumetanide was added. Also, we found that the phosphorylation of c-Jun NH2 -terminal kinase (JNK), which regulates the activity of various transcriptional factors, was reduced by bumetanide treatment. Conclusively, these findings suggest that NKCC1 in osteoblasts has a pivotal role in 1,,25(OH)2D3 -induced osteoclastogenesis partly via the phosphorylation of JNK. [source] Effect of Clostridium perfringens epsilon toxin on MDCK cellsFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2001Erika Borrmann Abstract Epsilon toxin is one of the major lethal toxins produced by Clostridium perfringens type D and B. It is responsible for a rapidly fatal disease in sheep and other farm animals. Many facts have been published about the physical properties and the biological activities of the toxin, but the molecular mechanism of the action inside the cells remains unclear. We have found that the C. perfringens epsilon toxin caused a significant decrease of the cell numbers and a significant enlargement of the mean cell volume of MDCK cells. The flow cytometric analysis of DNA content revealed the elongation of the S phase and to a smaller extent of the G2+M phase of toxin-treated MDCK cells in comparison to untreated MDCK cells. The results of ultrastructural studies showed that the mitosis is disturbed and blocked at a very early stage, and confirmed the toxin influence on the cell cycle of MDCK cells. [source] Lack of main K+ uptake systems in Saccharomyces cerevisiae cells affects yeast performance in both potassium-sufficient and potassium-limiting conditionsFEMS YEAST RESEARCH, Issue 5 2010Clara Navarrete Abstract A new YNB medium containing very low concentrations of alkali metal cations has been developed to carry out experiments to study potassium homoeostasis. Physiological characterization of Saccharomyces cerevisiae BY4741 strain and the corresponding mutant lacking the main potassium uptake systems (trk1 trk2) under potassium nonlimiting and limiting concentrations was performed, and novel important differences between both strains were found. At nonlimiting concentrations of KCl, the two strains had a comparable cell size and potassium content. Nevertheless, mutants were hyperpolarized, had lower pH and extruded fewer protons compared with the BY4741 strain. Upon transfer to K+ -limiting conditions, cells of both strains became hyperpolarized and their cell volume and K+ content diminished; however, the decrease was more relevant in BY4741. In low potassium, trk1 trk2 cells were not able to accomplish the cell cycle to the same extent as in BY4741. Moreover, K+ limitation triggered a high-affinity K+/Rb+ uptake process only in BY4741, with the highest affinity being reached as soon as 30 min after transfer to potassium-limiting conditions. By establishing basic cellular parameters under standard growth conditions, this work aims to establish a basis for the investigation of potassium homoeostasis at the system level. [source] Temporal dynamics and growth of Actinophrys sol (Sarcodina: Heliozoa), the top predator in an extremely acidic lakeFRESHWATER BIOLOGY, Issue 6 2006ELANOR M. BELL Summary 1. The in situ abundance, biomass and mean cell volume of Actinophrys sol (Sarcodina: Heliozoa), the top predator in an extremely acidic German mining lake (Lake 111; pH 2.65), were determined over three consecutive years (spring to autumn, 2001,03). 2. Actinophrys sol exhibited pronounced temporal and vertical patterns in abundance, biomass and mean cell volume. Increasing from very low spring densities, maxima in abundance and biomass were observed in late June/early July and September. The highest mean abundance recorded during the study was 7 × 103 Heliozoa L,1. Heliozoan abundance and biomass were higher in the epilimnion than in the hypolimnion. Actinophrys sol cells from this acidic lake were smaller than individuals of the same species found in other aquatic systems. 3. We determined the growth rate of A. sol using all potential prey items available in, and isolated and cultured from, Lake 111. Prey items included: single-celled and filamentous bacteria of unknown taxonomic affinity, the mixotrophic flagellates Chlamydomonas acidophila and Ochromonas sp., the ciliate Oxytricha sp. and the rotifers Elosa worallii and Cephalodella hoodi. Actinophrys sol fed over a wide-size spectrum from bacteria to metazoans. Positive growth was not supported by all naturally available prey. Actinophrys sol neither increased in cell number (k) nor biomass (kb) when starved, with low concentrations of single-celled bacteria or with the alga Ochromonas sp. Positive growth was achieved with single-celled bacteria (k = 0.22 ± 0.02 d,1; kb = ,0.06 ± 0.02 d,1) and filamentous bacteria (k = 0.52 ± <0.01 d,1; kb = 0.66 d,1) at concentrations greater than observed in situ, and the alga C. acidophila (up to k = 0.43 ± 0.03 d,1; kb = 0.44 ± 0.04 d,1), the ciliate Oxytricha sp. (k = 0.34 ± 0.01 d,1) and in mixed cultures containing rotifers and C. acidophila (k = 0.23 ± 0.02,0.32 ± 0.02 d,1; maximum kb = 0.42 ± 0.05 d,1). The individual- and biomass-based growth of A. sol was highest when filamentous bacteria were provided. 4. Existing quantitative carbon flux models for the Lake 111 food web can be updated in light of our results. Actinophrys sol are omnivorous predators supported by a mixed diet of filamentous bacteria and C. acidophila in the epilimnion. Heliozoa are important components in the planktonic food webs of ,extreme' environments. [source] Nitrogen-Rich Compounds of the Lanthanoids: The 5,5,-Azobis[1H -tetrazol-1-ides] of some Yttric Earths (Tb, Dy, Ho, Er, Tm, Yb, and Lu)HELVETICA CHIMICA ACTA, Issue 7 2009Georg Steinhauser Abstract A set of N-rich salts, 3,9, of the heavy lanthanoids (terbium, 3; dysprosium, 4; holmium 5; erbium, 6; thulium, 7; ytterbium, 8; lutetium, 9) based on the energetic 5,5,-azobis[1H -tetrazole] (H2ZT) was synthesized and characterized by elemental analysis, vibrational (IR and Raman) spectroscopy, and X-ray structure determination. The synthesis of the lanthanoid salts 3,9 was performed by crystallization from concentrated aqueous solutions of disodium 5,5,-azobis[1H -tetrazol-1-ide] dihydrate (Na2ZT,2,H2O; 1) and the respective Ln(NO3)3,5,H2O and yielded large rhombic crystals of the type [Ln(H2O)8]2(ZT)3,6,H2O in ca. 70% of the theoretical yield. The compounds 3,9 are isostructural (triclinic space group P) to the previously published yttrium salt 2; they show, however, a clear lanthanoid contraction of several crystallographic parameters, e.g., the cell volume or the LnO bond lengths of the Ln3+ ions and the coordinating H2O molecules. The lanthanoid contraction influences the strengths of the H-bonds, which can be observed as a red shift by 4,cm,1 in the characteristic IR band, in particular from 3595,cm,1 (3) to 3599,cm,1 (9). In good agreement with previous works, 2,9 are purely salt-like compounds without a coordinative bond between the tetrazolide anion and the Ln3+ cation. [source] Differential long-term neurotoxicity of HIV-1 proteins in the rat hippocampal formation: A design-based stereological studyHIPPOCAMPUS, Issue 2 2008Sylvia Fitting Abstract The human immunodeficiency virus type 1 (HIV-1) proteins, gp120 and Tat, are believed to play a role in mediating central nervous system (CNS) pathology in HIV-1 infected patients. Using design-based stereology, we examined the role of neonatal intrahippocampal injections of gp120 and Tat on the adult hippocampus (,7˝ month). Postnatal day (P)1-treated Sprague-Dawley rats were bilaterally injected with vehicle (VEH, 0.5 ,l sterile buffer), gp120 (100 ng), Tat (25 ,g) or combined gp120 + Tat (100 ng + 25 ,g). Using Nissl-stained tissue sections, we quantified total neurons in five subregions of the rat hippocampus [granual layer (GL), hilus of the dentate gyrus (DGH), cornu ammonis fields (CA)2/3, CA1, and subiculum (SUB)], and total glial cells (astrocytes and oligodendrocytes) in two subregions (DGH and SUB). Estimates of cell area and cell volume were taken in the DGH. There was a significant reduction of neuron number in the CA2/3 subfield by Tat and gp120, and a significant reduction in the DGH by Tat only. For glial cells, numbers of astrocytes in the DGH and SUB were increased by the Tat protein, whereas no effects were noted for gp120. Finally, for oligodendrocytes Tat increased cell number in the DGH but not in any other region; gp120 had no detectable effect in any brain region. Estimates of cell area and cell volume of the three different cell types revealed no significant differences between treatments. Collectively, these results suggest differential effects of gp120 and Tat on the estimated total number of neurons, as well as on the number of glial cells. © 2007 Wiley-Liss, Inc. [source] Ultrarapid Microwave Synthesis of Superconducting Refractory CarbidesADVANCED MATERIALS, Issue 44 2009Simon R. Vallance Nb1,xTaxC Carbides can be synthesized by high power MW methods in less than 30,s. In situ and ex situ techniques probing changes in temperature and dielectric properties with time demonstrate that the reactions self-terminate as the loss tangent of the materials decreases. The resulting carbides are carbon deficient and superconducting; Tc correlates linearly to unit cell volume, reaching a maximum at NbC. [source] | ||||||||||||||||||||||||||||||||||||||||||||||