The photodynamic inactivation of coliphage T3 was studied over a wide range of concentrations of the dye proflavine. With 2 x 10(7) phage/ml, two modes of inactivation were observed. Between 0.25 and 12 to 13 mug/ml, inactivation was biphasic. There was an initial first-order inactivation (Rx1) which became temporally associated with an apparently multiorder process (Rx2) at higher light doses....

The relative independence of serum T-3 from changes in thyroid binding protein levels makes it a more effective screening test for hyper- and hypothyroidism than the T-4 assay alone. In fact, its efficiency is comparable to that of the free T-4 index.

A thyroid suppression test is suggested which relies on the change in concentration of serum thyroxine as the index of thyroid response to the administration of triiodothyronine. The test has been carried out in 16 healthy volunteers and in 27 patients referred for routine suppression tests. This index appears to be sensitive and safe and results in a reduction in the required dosage of triiodo...

The relationship between free thyroxine concentration and thyroxine turnover was studied during thyroid suppression with triiodothyronine. Although there was some increase in the proportion of serum thyroxine bound to thyroxine-binding globulin, the ratio of ultrafilterable to protein-bound hormone was not significantly affected. The fractional disappearance rate of thyroxine increased from an ...