Frank C. Larson

In vitro conversion of thyroxin to triiodothyronine by kidney slices.

Summary and Conclusions 1. Chromatographically pure I131 labelled 1-thyroxin was added to surviving kidney slices which were incubated in a modified Krebs-Ringer phosphate solution. 2. Following incubation, the slices were homogenized, extracted with butanol and the thyroxin and triiodothyronine separated and identified by paper chromatography. 3. The triiodothyronine was found to be radioactive. This was taken as evidence of deiodination of thyroxin to triiodothyronine. 4. Conversion of thyroxin to triiodothyronine was reduced by excess iodide and abolished by boiling the tissue or by the addition of potassium cyanide to the media.

Thyroxine binding capacity of serum alpha globulin in hypothyroid, euthyroid, and hyperthyroid subjects.

Circulating thyroxine is associated with a specific serum alpha globulin ( 1-6). This thyroxinebinding globulin (TBG) appears to exist in plasma in quantity greater than is required to bind endogenous thyroxine, for it will bind additional thyroxine when added in vitro (6-8). This capacity of TBGto bind exogenous thyroxine in vitro appeared in prelinary studies (9) to depend upon the state of thyroid gland activity. The purpose of this paper is to report in more detail the capacity of the serum of hypothyroid, euthyroid, and hyperthyroid subjects to bind added thyroxine.

Probabilistic information processing: Implementation and evaluation of a Semi-PIP diagnostic system

Abstract A computer-aided diagnostic system called Semi-PIP which uses subjectively estimated patient attribute-disease relationships and is sensitive to conditional dependencies is described and tested. This model uses the best of four tested methods to subjectively classify data into conditionally independent complexes. Its performance is compared to two models which ignore conditional dependencies, and to three physicians diagnosing on the basis of symptoms, physical signs and laboratory information. Analysis of the results indicates that Semi-PIP is superior to the other computer models, and almost as accurate as the majority physician diagnosis.

Single Dimension Chromatographic Separation of Thyroxin and Triiodothyronine.

Summary A method is described by which iodine-containing amino acids, including thyroxin and triiodothyronine can be adequately separated by single dimension chromatography. Physiological quantities of labelled thyroxin and triiodothyronine have been added to serum, extracted with butanol and separated by this method.

Preliminary observations on a new derivative of isoniazid (Ro 2-4969).

Summary 1. Ro 2-4969, a compound of low solubility, related to isoniazid, has been administered experimentally to human subjects to determine the rate and extent of absorption from the gastrointestinal tract. 2. The compound or its derivatives appeared in the plasma and, probably because of slow absorption, detectable and clinically significant amounts remained for a longer period than when the highly soluble isoniazid was administered. 3. The drug administered in a single daily dose of 10 mg/kg/day was found to maintain drug concentrations of one μg/ml of plasma without dangerous cumulative effect. 4. No toxic reactions have been observed in 26 patients treated for 2 months or more.