Effects of ouabain on potassium transport in the perfused bullfrog kidney.

We studied the effect of ouabain on transepithelial and cellular potassium transport in the isolated perfused bullfrog kidney. We used recently developed techniques for estimating the unidirectional reabsorptive and secretory K fluxes (Jr and Js) and measuring the kinetics of cellular K transport. Two hours of perfusion with 1 X 10(-6) M ouabain did not affect GFR, reduced fractional Na reabsorption 57%, increased K excretion 41%, and inhibited Jr 34%. Js rose 68% at 60 min and then returned to the control level. Ninety minutes of perfusion with 5 X 10(-6) M ouabain reduced GFR 28% and fractional Na reabsorption 76%. K excretion rapidly increased 71% within 30 min and then fell to 60% of the control level, while Jr fell 64%. Js rose 42% in 30 min and then fell to 23% of the control level. Both doses reduced K uptake into cellular pools from the circulation and increased the rate coefficients for efflux into tubular fluid. The data indicate that ouabain inhibited reabsorption and transiently accelerated the rate of loss of K from the cells into the tubular fluid. This initially masked the ultimate inhibition of K secretion from the circulation into the tubular fluid.     

Failures in the management of congenital hip displacement in the newborn.

Congenital hip displacement in the newborn presents in two forms: (1) Those babies in whom the capsule of the hip-joint is mechanically stretched. Spontaneous reduction and recovery is high in this group, if the babies are nursed in the prone posture with double nappies (Fig 5). (2) One in a thousand babies is born with infolding of the posterior capsule and secondary contracture of the anterior capsule. This soft tissue deformation occurs in varying degrees, but it frequently prevents spontaneous reduction. Most of these cases are missed and present as infantile congenital hip displacements, when the child is 12-18 months old. In those who are unfortunate enough to be detected and treated conservatively, in the first year of life, there is a high risk of iatrogenic bony deformation. For, as in talipes equinovarus, the bony components of the neonatal hip-joint are more susceptible to mechanical compression than the soft tissue structures.     

Solid-phase radioimmunoassay techniques for the detection of African swine fever antigen and antibody.

A solid phase radioimmunoassay (RIA) has been successfully developed to measure both African swine fever virus (ASFV) antigen and antibody. Studies show that the assay is reproducible and will detect limiting antigen concentrations equivalent to 50--500 HAD50/ml. Both direct and indirect antibody RIA have been developed and have proved to be approximately 100 times fore sensitive than the complement fixation test at present available and 1000 times more sensitive than the immuno-electro-osmophoresis test for the detection of ASFV antibody.