With the widespread use of tricyclic antidepressant drugs, the relationship between the concentration of the drug in the plasma and the therapeutic response is of considerable interest. We describe a double-isotope derivative dilution procedure for measuring plasma nortriptyline. In the method, [14C]nortriptyline is used for estimating procedural losses and [3H]acetic anhydride for derivative f...

An analysis of the clinical value of radioisotopic lung function (RLF) tests has been carried out on the results of studies in 123 children with heart or lung disease. The overall incidence of useful RLF tests was 53%, but in children between 6 months and 6 years the incidence was higher (69%). The incidence of useful RLF test was similar whatever the question to be answered, although rather hi...

T HE ASSOCIATION of thrombocytopenia with giant hemangioma has been documented in approximately 40 cases since the first report of Kasabach and Merritt in 1940. The mechanism of thrombocytopenia is thought to he related to the trapping of platelets by the abnormal endothelium of the tumor, and the accumulation of material presumably derived from the platelets has been demonstrated by histologic...

In one form or another, geochronologists have been practicing thermochronology1, the use of radioisotopic dating to constrain thermal histories of rocks and minerals, for over 40 years. Building from lessons learned over these four decades, thermochronology continues to evolve due to technical developments, increasingly sophisticated theoretical models, and an expanding range of applications in...

Radioisotopic analyses for carnitine content were done on infant formula, formulas for tube feeding, food supplements, and chemically defined diets. The carnitine content of the diets depend on the protein source. Products whose main protein source is soy protein isolate, casein, or egg white solids contain 4 nmole carnitine per milliliter or less, with most of them containing undetectable amou...