a simple, mild and practical procedure has been developed for the synthesis of symmetrical and unsymmetrical ethers by using dmso, tbai in the presence of k2co3. we extended the utility of  potassium carbonate as an efficient base for the preparation of ethers. a wide range of alkyl aryl and dialkyl ethers are synthesized from treatment of aliphatic alcohols and phenols with various alkyl halid...

a sensitive and selective extraction - spectrophotometric method for the determination of trace amounts of palladium is reported. the method is based on quantitative extraction of brownish tetrabutylammoium tetraiodopalladium (ii) ion pair into a small valume of chloroform at ph 1.3-12.0, followed by spectrophotometric measurements. the beer's law is obeyed over the range 0.02-1.09 mgml-1 at 44...

Although it is beyond doubt that mammary cells accumulate iodide via a Na+-dependent transport mechanism, it is not clear if this is the only pathway for iodide transport in mammary tissue. In view of this, experiments were designed to test for the presence of an anion-exchange pathway which could mediate the transport of iodide into mammary cells; thus, the effect of external iodide on sulfate...

A method for the determination of serum protein-bound iodine (PBI) is presented. Chioric acid digestion is carried out in a single tube as described by other authors. In order to shorten the period when close supervision is necessary, the digestion process has been reduced to 1 hour and the estimation completed within 4 hours. The method has been modified to make it a more manageable routine pr...

Previous studies of thyroid function during various infections have yielded conflicting results, but most have suggested an acceleration of peripheral thyroxine (T(4)) turnover during the acute infectious illness. In the present studies, thyroid function was examined by a method allowing simultaneous analysis of both endogenous thyroidal release and peripheral T(4) disposal in normal volunteers...

As judged from both paper and column chromatography, slices or homogenates of liver from rats fasted for 48 h displayed a lesser rate of generation of (125)I-labeled 3,5,3'-triiodothyronine (T(3)) from (125)I-labeled thyroxine (T(4)) added to incubation media than did preparations from normal chow-fed animals. A similar defect in the conversion of T(4) to T(3) in the livers of fasted animals wa...

The absence of TSH-stimulated radioiodide uptake in differentiated thyroid cancer is associated with a high recurrence rate and reduced survival. We studied regulation of the sodium/iodide symporter gene in human papillary thyroid cancer cell lines (BHP) and primary human thyroid cells. BHP cells expressed very low levels of sodium/iodide symporter mRNA and did not concentrate iodide, but iodid...

Previous studies have demonstrated that short-term oral iodide administration, in doses ranging from 1500 micrograms to 250 mg/day, has an inhibitory effect on thyroid hormone secretion in normal men. As iodide intake in the USA may be as high as 800 micrograms/d, we investigated the effects of very low dose iodide supplementation on thyroid function. Thirty normal men aged 22-40 years were ran...