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A method for free thyroxine estimation in serum, using labelled thyroxine and Sephadex G-25 has been developed.The experiment has been carried out by incubating labelled thyroxine with serum samples and separating the free thyroxine from bound protein in the serum by gel filtration after complete equilibrium between exogenous and endogenous thyroxine. Factors affecting the free thyroxine ratio such as volume of serum used, concentration of labelled thyroxine, time and temperature of incubation were studied and the optimum conditions for the test were selected.The sensitivity of the technique was determined by carrying out twelve estimations of the free thyroxine ratio on samples of pooled normal serum, pooled hypothyroid serum, and pooled hyperthyroid semm. In addition free thyroxine ratio leas determined for 23 hypothyroidisms, 99 euthyroid patients, 40 untreated thyrotoxicosis and 50 normal serum samples. A good correlation with the thyroid status of the patients (as determined) clinically and with radioiodine techniques was observed.

A precise and accurate method is being developed for the determination of T3/T4 ratio. This method depends on using serum of different thyroid cases for the assesment of T3/T4 ratio. It has been found that the best temperature of storage is 0.0 °C to 4 °C before extracting the iodinated tyrosines and thyronines.Iodination with 125I was done according to our previous technique to render the separated thyronine radioactive. Scanning method helped for the determination of T3/T4 ratio. The results were confirmed by sensitivity and recovery test and statistically analyzed. 100 cases were investigated comprising hypo-, eu-, and hyperthyroid cases.

The dependence of photosynthetic yields on both sodium adsorption ratio and osmotic pressure of irrigation water is discussed. As a first example, Zea mays seedlings were exposed to C14O2in closed photosynthetic chambers for 24 hrs. The chromatographic study of aqueous and alcoholic extracts as well as the hydrolyzed tissue are shown in special tables. Other data concerning respiration rate as well as carbohydrates and mineral metabolism are also studied.

1.The estimation of unsaturated fatty acids of three varieties of linseed oil is carried out by the paper chromatography technique using131I for saturating the acids.2.The relationship between the total and individual unsaturated fatty acids content on one side, and the maximal spot activity on the other side, is linear and can be used as standard reference line.3.Determination of the Rf values of the three occuring unsaturated fatty acids, depends mainly on the change of the specific activity of the iodinating mixture.

P32 and C14 have been used together to identify and tgrace the photosynthates of Zea mays during the seedling stage. By this double labelling technique and single labelling with C14O2 and H3P32O4, carbohydrates, amino acids, and phosphoproteins were identified on paper chromatograms. Tables and figures summarise the results obtained under different mineral deficiency. These results indicate the effects of the absence of P, Mg, K, N, Ca, and trace elements on both respiration and photosynthesis.

Two S35-labelled hypoglycemic agents were prepared by the interaction of labelled sulphonamide and urea derivatives. The R values of the intermediates as well as the products wer determined and compared with tolbutamide. The purity of the products was checked by melting point determination, infrared spectrum, and radioactivity investigations. Localization of the separated products on the chromatograms was done by colour reaction, radioscaning, and radioautography. Distribution of the labelled drung in different tissues of rats was also carried out to prove the site of action of the drung and to show its accumulation. Counting of these tissues has been carried out by means of a liquid scintillation counter type Nuclear Chicago.

A radiochemical method for the identification of some steroids on electropherograms is described. A comparison between this method and another modified spectrophotometric method is given. The radiochemical method can be used for quantitative work; the relationship between the concentration of the hydrazones and the radioactivity gained by the steroids is linear. This technique is superior to any colorimetric one, it needs less reagents and is not time consuming. Application of the method to other steroids is continued.