Cellular Water Content Research Articles

Some effects of ouabain on cellular ions and water in epithelial cells of toad urinary bladder.

Transepithelial sodium transport was virtually abolished when toad urinary hemibladders, mounted in chambers and short-circuited, were exposed on their serosal surface to ouabain, 10-2 M,for 60 minutes. Epithelial cells scraped from such hemibladders gained sodium and lost an equal quantity of potassium when compared with controls not exposed to cardiac glycoside. Their total cellular cation content, chloride content and water content were unchanged. Experiments in which 24-Na, amiloride, or sodium-free mucosal solutions were used, revealed that a large, though variable, percentage of the sodium gained by cells exposed to oubain, came from the mucosal medium, a finding consistent with the model of passive sodium entry from the mucosal medium followed by active sodium extrusion to the serosa. The oubain-insensitive maintenance of cellular volume which was observed did not depend upon transepithelial sodium transport which had been virtually completely inhibited by ouabain. Neither did the maintenance of a normal cellular potassium content depend upon transepithelial sodium transport, for cellular potassium was unaffected when the mucosal medium was sodium-free or when it contained sufficient amiloride, 10-3 M, to virtually abolish such transport.

Chloride and water distribution in human red cells.

1. The influence of the pH and the temperature on the cellular chloride and water content was investigated in human red cells, the cellular KC1 concentrations of which varied between 10 and 600 mM. The compositions of the media (10-600 mM-KC1, 1 mM-NaC1, 27 mM sucrose) at each single KC1 concentration were constant at the different values of the pH and the temperature. 2. The variation of the cellular KC1 concentration was obtained by washing the cells with KC1 salt solutions containing nystatin...

Bovine lipogenesis: Effects of anatomical location, breed and adipose cell size

1. 1. The incorporation of [1- 14C] acetate into total fatty acids and the activities of ‘malic enzyme’, NADP-isocitrate dehydrogenase, glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were higher in adipose tissue from 14-month-old Hereford × Angus steers than in tissue from 14-month-old Holstein steers. 2. 2. Adipose tissue from 8-month-old Hereford steers was less active in lipogenesis than that from older steers of the Holstein or Hereford × Angus groups. 3. 3. The conversion of [1- 14C] acetate to 14CO 2 was directly proportional to adipose cell volume, while fatty acid synthesis was positively related to cell volume in the lipogenically more active subcutaneous Hereford × Angus tissue and inversely related to adipose cell volume in the perirenal tissue from the two groups of 14-month-old steers. 4. 4. The activities of the four NADPH-generating enzymes were positively related to the average adipose cell volume, cellular water content and cellular content of soluble protein.

Skylab experiment results: Hematology studies

These studies were designed and coordinated to evaluate specific aspects of man's immunologic and hematologic systems which might be altered by or respond to the space flight environment. The biochemical functions investigated included cytogenetic damage to blood cells, immune resistance to disease, regulation of plasma and red cell volumes, metabolic processes of the red blood cell, and physical chemical aspects of red blood cell functions. Only minor changes were observed in the functional capacity of erythrocytes as determined by measuring the concentrations of selected intracellular enzymes and metabolites. Tests of red cell osmotic regulation indicated some elevation in the activity of the metabolic dependent Na-K pump, with no significant alterations in the cellular Na and K concentrations or osmotic fragility. A transient shift in red cell specific-gravity profile was observed on recovery, possibly related to changes in cellular water content. Measurements of hemoconcentration (hematocrit, hemoglobin concentration, red cell count) indicated significant fluctuations postflight, reflecting observed changes in red cell mass and plasma volume. There was no apparent reticulocytosis during the 18 days following the first manned Skylab mission in spite of a significant loss in red cell mass. However, the reticulocyte count and index did increase significantly 5 to 7 days after completion of the second, longer duration, flight. There were no significant changes in either the white blood cell count or differential. However, the capacity of lymphocytes to respond to an in vitro mitogenic challenge was repressed postflight, and appeared to be related to mission duration. The cause of this repression is unknown at this time. Only minor differences were observed in plasma protein patterns. In the second mission there were changes in the proteins involved in the coagulation process which suggested a hypercoagulative condition.

Maturation-dependent alterations in [3H]GABA compartmentalization in neural tissue in vitro

The uptake and subcellular distribution of [3H]GABA into slices of mouse cerebral cortices were studied at various stages of postnatal development.(1)The subcellular distribution of [3H]GABA was observed to change during neural maturation.(2)Cellular uptake of [3H]GABA was considerably greater in immature as compared to mature cerebral cortical slices.(3)The radioactivity of extractable [3H]GABA associated with synaptosome enriched fractions was comparable across all ages of mice.(4)Control studies indicated that substrate limitations, cellular water content, extracellular space, retention of occluded radioactivity during preparation of subcellular fractions and tritiated water exchange could not account for the differences in subcellular compartmentalization of [3H]GABA associated with mouse age.(5)In synaptosome enriched fractions uptake specificity and uptake sensitivity to various inhibitors were comparable for tissues from all ages of mice.These findings are related to morphological alterations in the cerebral cortical fractions obtained from mice of different ages. An apparent paradox between biochemical and morphological observations suggests several possibilities regarding cerebral cortical development and the subcellular compartmentalization of GABA.

Electron microscope studies of frozen-substituted marine eggs. I. Conditions for avoidance of intracellular ice crystallization.

AbstractEggs of the marine clam Spisula solidissima were examined by the technique of freeze‐substitution. Morphology of the cytoplasm was investigated as a function of cellular water content using osmotic means to control water concentration. In eggs frozen in less than double strength sea water, ice crystallization usually occurred throughout the cell. In eggs frozen in double to triple strength sea water, 10–75% of the eggs were devoid of ice crystals in the cytoplasm and in triple strength sea water, also in the nucleus. From these results and from a detailed analysis of cells in which both ice crystals and ice crystal‐free regions occurred it is concluded that cells or parts of cells may be frozen free of ice crystals if their free water content is reduced. Reduction in free water content may occur in several ways: deliberate dehydration by osmotic means; accidental dehydration by evaporation of water from cells prior to freezing; osmotic dehydration of one region by an adjacent one in which ice crystallization is in progress. In ice crystal‐free cells, all common cell inclusions could be recognized.

NMR studies on the water immobilization by lipid systems in vitro and in vivo

The existence of immobilized water in lipid systems was observed both in vitro and in vivo, as shown by nuclear magnetic resonance (NMR) studies. It was found that by plotting T 2 versus η r values, the viscosity contribution to the broadening of the resonance line could be easily judged. When the viscosity (η r) increased more rapidly than the water relaxation time ( T 2) decreased, the broadening could have been due entirely to viscosity effects, but when the reverse held, the broadening was due mainly to a restricted mobility of the water molecules. It was established that both polar lipid micelles and RNA solutions were able to restrict the water mobility on their highly charged surfaces, while weakly charged molecules (dextran and bovine serum albumin) were unable to show this phenomenon. When the systems were exposed to the known salt-breaking effect of CaCl 2, the existence of irrotationally bound water was confirmed by the peak height increments of the water resonance signal. The amount of immobilized water (10.0% of the total in a 2% lipid dispersion) decreased initially in proportion to the ionic concentration: 3.4% of water was liberated by 0.033 M CaCl 2 against 6.3% of water liberated by 0.066 M CaCl 2. Experiments undertaken with living microorganisms showed that there was a marked effect of Ca 2+ on the cellular water content. The amount of liberated water followed an increment related to the presence of Ca 2+ in the environment. The lipid contribution to the water immobilization phenomena in vivo seems to be clearly established, especially if it is taken into account that during the salt-breaking effect on the cellular water, there was also an increment of the lipid signal height. This may be interpreted as a higher degree of mobility of the cellular lipid molecules when the immobilized water of their charged surface was removed. In other words, there was a mutual immobilization of the water and the lipid. Ionic environmental changes must cause variations in the thickness of the water layer around the polar heads of the lipid molecules. The remarkable permeabilities thus produced are discussed.

CAT HEART MUSCLE IN VITRO. 8. ACTIVE TRANSPORT OF SODIUM IN PAPILLARY MUSCLES.

The cells of cat right ventricular papillary muscles were depleted of K and caused to accumulate Na and water by preincubation at 2-3 degrees C. The time courses of changes in cellular ion content and volume and of the resting membrane potential (V(m)) were then followed after abrupt rewarming to 27-28 degrees C. At physiological external K concentration ([K](o) = 5.32 mM) recovery of cellular ion and water contents was complete within 30 minutes, the maximal observable rates of K uptake and Na extrusion (Deltammol cell ion/(kg dry weight) (min.)) being 3.4 and 3.6, respectively. The recovery rate was markedly slowed at [K](o) = 1.0 mM. Rewarming caused V(m) measured in cells at the muscle surface to recover within from <1 to 9 minutes, but only slight restoration of cellular ion contents (measured in whole muscles) had occurred after 10 minutes. Studies of recovery in NaCl-free sucrose Ringer's solution made it possible to separate the ouabain-insensitive outward diffusion of Na as a salt from a simultaneous ouabain-sensitive Na extrusion which is associated with a net cellular K uptake. A hypothesis consistent with these observations is that rewarming may activate a ouabain-sensitive "electrogenic" mechanism, most probably the net active transport of Na out of the cell, from which net K uptake may then follow passively.

Effect of Gamma Irradiation on Glucose Utilization, Glutathione, and Electrolyte Content of the Human Erythrocyte

Samples of freshly drawn heparinized human blood were irradiated with 10,000 to 40,000 rads from a Co/sup 60/ unit and then incubated at 37 deg C. Under these conditions a greater loss of K took place from the irradiated erythrocytes than from nonirradiated controls; the loss of K was partly replaced by Na. In the range examined this prolytic effect was found to be proportional to the irradiation dose. Removing the leukocyte fraction before irradiation or suspending the irradiated erythrocytes in nonirradiated plasma had no effect on these phenomena. No increased prolysis could be demonstrated when control erythrocytes were suspended in irradiated plasma. The excessive loss of K in the irradiated engthrocnes was not accompanied by a significant change in osmotic fragility, glucose uttlization, reduced glutathione content, and stability, over that found in corresponding controls. No extra increase in cellular volume and water content of the cells, and no hemolysis, which could be attributed to the irradiation, occurred. Under normal conditions, erythrocytes maintain their cation content by a complicated enzymatic process, for which glucose metabolism furnishes the energy, and in which reduced glutathione is presumed to play a role. Most instances of prolysis studied so far have been the resultmore » of a disturbance in this enzymatic process. It appears that the prolysis caused by irradiation is due to a different mechanism, possibly to a damaging effect on the structure of the cell membrane.« less

Relative humidity and the killing of bacteria: the variation of cellular water content with external relative humidity or osmolality.

SUMMARY: The paper deals with the relationship betweeen the water content of washed Serratia marcescens and the thermodynamic activity of water, a w, over the range 0 < a w < 1.0. Two overlapping types of measurement are used: osmotic water exchange and water-vapour sorption. The data are given in terms of the equation w = Bm -r where w is water content, m is external osmolality (actual or effective, depending upon the technique used), B is a constant and r has values which can be interpreted in terms of the type of process involved: e.g. in the initial stages of osmotic dehydration, r of unity would indicate ideal solution behaviour; in the final stages of drying, any constant value of r would conform to an adsorption function like that of Halsey (1948). The data obtained by the two techniques used fall on a single curve with several zones including (a) non-ideal solution behaviour at high a w, (b) two intersecting ‘co-operative adsorption’ zones at very low a w, and (c) a region of variable r where processes such as dissolution of small molecules and ‘saturated’ swelling of interlinked polymeric structures are presumed to occur. It is thought that detailed interpretation of the unified water uptake curves would be valuable in understanding mechanisms of humidity-dependent loss of viability, in particular the zones of exceptionally rapid attenuation.

Interaction of nutrition and air temperature with water metabolism of Merino wethers shorn in winter

p&gt;Field observations were made on Peppin Merino wethers maintained at 6 and 9 per acre throughout the year on improved pasture in Canberra. Estimations of water distribution with the use of tritium, thiocyanate, and T1824 indicated that stocking rate in autumn had little effect on body composition or water intake. Before shearing in July, however, the 9-per-acre sheep had lost 16% more weight than those at 6 per acre, although body water distribution was similar in the two groups. After shearing, both groups shivered continuously for 3 weeks. The 9-per-acre animals had lower rectal and higher skin temperatures than the 6-per-acre sheep. Skin and rectal temperatures were reciprocal to wind velocity. Both groups lost over 3 kg weight (5.9 and 8.4% of body weight) in 2 weeks, but in the 9-per-acre sheep, body water increased by 8.7% while in the 6-per-acre group 4.4% of body water was lost. The 9-per-acre sheep lost 30.7% of tissue solids, compared with 7.5% in the better-fed animals. It is likely that cellular water content increased in the 9-per-acre animals. An increase in density of stocking from 6 to 9 per acre cost three times as much tissue and fat during the cold period, while this loss of solids was partly obscured by replacement of tissues with water.