Biomedical subjects
Publications and source records attributed to E Painter.
The use of an internal support of siliconized glass beads 6 millimeters in diameter was found to improve markedly the flow rates obtainable with porous Sephadex gels without significant alteration of other properties of the gels. The method may be generally applicable in situations where rapid separations on Sephadex are required.
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1. The instantaneous impedance method has been used to study the effects of antidiuretic hormone (ADH) on frog skin.2. The resting skin may be represented by a parallel RC network with a single time constant.3. Antidiuretic hormone causes an increase in conductance and capacitance and in some cases the appearance of a polarization angle.4. The structures in the skin responsible for the transients are located in the outermost membranes.5. The effects of ADH have been interpreted in terms of the formation of water-filled sodium-permselective pores in the outer facing membranes which occupy, at most, 0.3% of the skin surface. These pores constitute a parallel, and hence additive, capacitance with that of the normally ion impermeable parts of the cell surface, and in addition are responsible for the increase in conductance. The polarization angle is due to the polydisperse nature of the skin after hormone treatment.
1. Substitution of chloride by isethionate reduces the short circuit current (SCC) and increases the potential of isolated frog skin. In sodium isethionate Ringer antidiuretic hormone and choline chloride increase the SCC, whereas theophylline is ineffective.2. Frog skins treated on the outside with copper ions always show an increased potential when bathed in normal Ringer solution. The SCC may be moderately increased or decreased.3. Theophylline increases skin thickness and cell volume in non-short-circuited skins.4. The ways in which the theophylline-induced increase in chloride permeability affects sodium transport is discussed, together with the requirements for a permeant anion in both short- and open-circuited skins.
1. Impedance loci for frog skins have been calculated by computer analysis from voltage transients developed across the tissues.2. Attention has been paid to simultaneous changes in conductance and capacitance of skins treated either with antidiuretic hormone (ADH) or with theophylline. These drugs always caused an increase in conductance and usually the skin capacitance also increased. However, changes in conductance were not correlated with capacitance changes.3. Changes in capacitance caused by the drugs may represent pore formation in the barrier to water flow, since both drugs increase hydro-osmotic flow in epithelia. If this interpretation is correct, then 0.14% of the membrane area forms water-permeable pores in response to a maximal dose of ADH. This value is somewhat less than the value obtained previously (0.3%) by graphical analysis.4. A theoretical account is given of the relative accuracy of the computer method and the graphical method for voltage transient analysis.
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1. The effects of antidiuretic hormone (ADH), theophylline and cyclic 3',5'-adenosine monophosphate (AMP) on membrane potentials in frog skin have been investigated.2. Membrane potentials across the outer and inner facing membranes were recorded in both normal and current clamped skins. In the latter condition active transport of sodium had been abolished by ouabain or metabolic inhibitors, but ionic gradients were maintained by passing current through the skin from the inside.3. ADH increases the potential across the outer facing membranes and reduces the skin resistance. The results are consistent with ADH causing an increase in permeability of the outer facing membranes to sodium ions.4. Theophylline reduces the skin potential by reducing specifically the potential across the outer facing membranes. At the same time the skin resistance is reduced. Theophylline acts by increasing the permeability of the outer facing membranes to chloride ions.5. Cyclic 3',5'-AMP causes a biphasic potential change accompanied by an increase in skin resistance.6. Metabolic inhibitors block the response of the skin to ADH but not to theophylline.7. Separate explanations for the increase in sodium transport by ADH, theophylline and cyclic 3',5'-AMP are discussed. It is not necessary to involve cyclic AMP in order to explain the effects of either ADH or theophylline.
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Asthma is the most common of the chronic lung diseases diagnosed in children and accounts for a large percentage of emergency department/hospital admissions. Recently, the use of continuous administration of Beta-adrenergic agents has been found to be a safe and effective method of therapy for the pediatric patient experiencing severe asthma. An understanding of equipment, monitoring parameters, and nursing implications can help prepare pediatric nurses to provide care for children receiving continuous nebulization. An urban hospital in the northeastern United States organized a multidisciplinary team to investigate the use of continuous nebulization of Beta 2 agonists in the care of the pediatric patient experiencing an acute asthma episode.