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Osmotic disorder

A number of different water quality parameters such as concentration (and type) of DOC, pH, salinity and sub-optimal or insuflficient concentrations of specific ions or minerals could affect the biotic responses to UVR. The presence of DOC is in most cases the main determinant of UV attenuation and effects on freshwater metazoans (see Chapter 3), and yet increased DOC also yields increased production of ambient free radicals and oxidants the net effect on the biota is in general positive. The role of inorganic parameters is less well known. Under laboratory conditions, swollen body tissue may be observed in UV treated freshwater invertebrates animals, which could indicate osmotic disorder [15]. This could indicate that ionic content or salinity per se could be one determinant to UV tolerance, but Hessen [15] found no effect of salinity in the range from 250 to 1000 pScm in D. pulex exposed to artificial UVR (peak wavelength 312 nm). [Pg.418]

If the patient is to receive an osmotic diuretic, the focus of the assessment is on the patient s disease or disorder and the symptoms being treated. For example, if the patient has a low urinary output and the osmotic diuretic is given to increase urinary output, the nurse reviews the intake and output ratio and symptoms the patient is experiencing. In addition, the nurse weighs the patient and takes the vital signs as part of the physical assessment before starting drug therapy. [Pg.449]

Osmotic diuretics such as mannitol act on the proximal tubule and, in particular, the descending limb of the Loop of Henle — portions of the tubule permeable to water. These drugs are freely filtered at the glomerulus, but not reabsorbed therefore, the drug remains in the tubular filtrate, increasing the osmolarity of this fluid. This increase in osmolarity keeps the water within the tubule, causing water diuresis. Because they primarily affect water and not sodium, the net effect is a reduction in total body water content more than cation content. Osmotic diuretics are poorly absorbed and must be administered intravenously. These drugs may be used to treat patients in acute renal failure and with dialysis disequilibrium syndrome. The latter disorder is caused by the excessively rapid removal of solutes from the extracellular fluid by hemodialysis. [Pg.324]

A number of ocular surface disorders collectively termed as Dry Eye Syndromes have also been associated with the conjunctiva. For example, a deficiency and/or imbalance in compositions of the tear film is often found on the ocular surface during keratoconjunctivitis sicca. Since the conjunctiva plays a direct role in the maintenance of the tear fluid stability via secretion of mucin [1] by its resident goblet cells [4] and basal fluid secretion driven by electro-osmotic gradients across the tissue [3], the conjunctiva is a well deserved, but not intensively studied, target of interest in research efforts aimed against combating Dry Eye Syndromes. [Pg.313]

Modern diuretics (natriuretics, saluretics), as used in the treatment of hypertension and heart failure, are administered with the aim to enhance the renal excretion of sodium ions and water. Older diuretics, such as the osmotic diuretic agents, are of little interest in the treatment of the aforementioned cardiovascular disorders, but may be used to lower intracranial pressure associated with brain edema. [Pg.342]

The final colligative property, osmotic pressure,24-29 is different from the others and is illustrated in Figure 2.2. In the case of vapor-pressure lowering and boiling-point elevation, a natural boundary separates the liquid and gas phases that are in equilibrium. A similar boundary exists between the solid and liquid phases in equilibrium with each other in melting-point-depression measurements. However, to establish a similar equilibrium between a solution and the pure solvent requires their separation by a semi-permeable membrane, as illustrated in the figure. Such membranes, typically cellulosic, permit transport of solvent but not solute. Furthermore, the flow of solvent is from the solvent compartment into the solution compartment. The simplest explanation of this is the increased entropy or disorder that accompanies the mixing of the transported solvent molecules with the polymer on the solution side of the membrane. Flow of liquid up the capillary on the left causes the solution to be at a hydrostatic pressure... [Pg.11]

Q7 Laxatives are often misused/abused, for example in slimming disorders, to increase gut transit rate and so limit absorption of foods. Side effects which may occur include flatulence, and abdominal distension or discomfort with bulk-forming and osmotic laxatives. Other adverse effects may include diarrhoea, nausea, vomiting, weakness, dehydration and electrolyte imbalances, for example hypokalaemia. The most prominent side effect of the powerful stimulant/irritant laxatives is abdominal cramping, which is due to increased peristalsis. [Pg.264]

Osmotic diarrhoea occurs when a non-absorbable substance draws fluid into the intestine by osmosis, for example lactase deficiency, when unabsorbed lactose remains in the intestine. This type of problem also occurs in malabsorption disorders, for example in celiac disease. [Pg.266]

Because the particle lattice is assumed to be static, the osmotic pressure term due to particle conformation for the disordered suspension derived by Carnahan and Starling [25] and used by Dickinson [26] and Evans and Napper [27] must be added to the previous equation ... [Pg.513]

Figure 11.6 is a plot of the osmotic pressure versus volume fraction for a suspension with different widths, tr = In a-g, of the log-normal particle size distributions where Og is the geometric mean size and a-g is the geometric standard deviation. As the width of the size distribution increases, the osmotic pressure decreases for a particular volume fraction. With this osmotic pressure, we can evaluate the order—disorder transition for an electrostatically stabilized suspension, which is discussed next. [Pg.516]

FIGURE 11.10 Gibbs free energy, G, versus osmotic pressure, II, for a suspension of hard spheres showing the intersection of the disordered and the ordered curves corresponding to the disorder-order transition with 4a-a%/3 = 0.74. Adapted from Cast et al. [63]. Reprinted with permission Academic Press. [Pg.522]

The incidence of heterozygous -thalassemia among the American Negro is approximately 0.8% (G12). Subjects with this disorder have a Hb level of 10-13 g/100 ml, with MCV values of 70-75 and MCHC values of 26-30%. Osmotic fragility of the cells is decreased. Diagnosis is usually an accidental finding or results from family studies. [Pg.189]

At very low molecular densities, i.e. at very low Interfacial pressures, the mono-layer exhibits gaseous behaviour. The molecules are far apart, but, unlike in a three-dimensional gas, they are not completely disordered. Because of their amphi-polar nature, the molecules exhibit a preferential orientation relative to the surface-normal. As stated in sec. 3.1, the interfacial pressure exerted by an ideally dilute monolayer is equivalent to the osmotic pressure of an ideal three-dimensional solution. Ideal gaseous monolayer behaviour means obe3dng relation [3.1.1]. [Pg.224]

A 2.16% dimethyl sulfoxide solution in water is iso-osmotic with serum. Dimethyl sulfoxide has been used as a 50% aqueous solution for instillation into the bladder in the treatment of interstitial cystitis it has also been tried clinically for a wide range of indications, including cutaneous and musculoskeletal disorders, but with little evidence of beneficial effects. [Pg.251]

Maintenance of water homeostasis is paramount to life for all organisms. In mammals, the maintenance of osmotic pressure and water distribution in the various body fluid compartments is primarily a function of the four major electrolytes, Na", K , Cl", and HCOi". In addition to water homeostasis, these electrolytes play an important role in the maintenance of pH, proper heart and muscle function, oxidation-reduction reactions, and as cofactors for enzymes. Indeed, there are almost no metabolic processes that are not dependent on or affected by electrolytes. Abnormal concentrations of electrolytes may be either the cause or the consequence of a variety of disorders. Thus determination of electrolytes is one of the most important functions of the clinical laboratory. Interpretation of abnormal osmolality and acid-base values requires specific knowledge of the electrolytes. Because of their physiological and clinical interrelationship, this chapter discusses determination. of electrolytes, osmolality, acid-base status, and blood oxygenation. [Pg.983]

Determination of plasma and urine osmolality can be useful in the assessment of electrolyte and acid-base disorders. Comparison of plasma and urine osmolalities can determine the appropriateness and status of water regulation by the kidneys in settings of severe electrolyte disturbances, as might occur in diabetes insipidus or the syndrome of inappropriate antidiuretic hormone (SIADH) (see Chapters 45 and 50). The major osmotic substances in normal plasma are Ha, Cr, glucose, and urea thus expected plasma osmolality can be calculated from the following empirical equation ... [Pg.992]


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