Practical considerations in analyzing radioreceptor assays by Scatchard analysis and capacity determination in irreversible hormone receptor interactions.

The Scatchard plot in a radioreceptor assay depends upon the definition of specific binding and the quality of the iodinated hormone used. Iodination of protein hormones may alter it so that it no longer binds to the receptor and methods are available to measure the extent of this inactivation. When appropriate corrections are made for specific binding and the amount of inactive iodinated hormone in an assay, both qualitative and quantitative differences were observed in estimates of binding capacity and affinity in some well characterised hormone receptor systems. Theoretical predictions derived from Scatchard analysis of irreversible unimolecular hormone-receptor interactions were applicable, both qualitatively and quantitatively to two irreversible hormone-receptor systems. A method described permits a more accurate estimate of capacity from radioreceptor assay data.

Irreversibility of the interaction of human growth hormone with its receptor and analysis of irreversible reactions in radioreceptor assays—Theoretical considerations.

Kinetic studies of the binding and dissociation of [125I]-human growth hormone to rabbit liver and mammary gland membrane receptors have showed that the binding of [125I]- human growth hormone was largely irreversible to liver membrane receptors and completely to the solubilised mammary gland receptor. As Scatchard analysis assumes complete reversibility of the hormone-receptor interaction the validity of estimates of affinity and capacity of receptors derived by this analysis may be questionable. Theoretical considerations show that in unimolecular irreversible interactions of hormone and receptor, a nonlinear (concave) or a linear Scatchard plot can be obtained. In linear Scatchard plots the capacity of the receptor obtained by extrapolation represents an overestimation of true capacity. This overestimation correlates with the value of the intercept in the Scatchard plot.

Development and Evaluation of Guidelines for the Clinical Management of HIV Infection in Adults and Children in Uganda

Objective: To assist health workers in diagnosis and treatment and rational use of drugs in symptomatic HIV infection. Methods: The different stages of the development and evaluation: 1. Development of draft guidelines through national consensus of policy makers; programme managers and AIDS Care workers. 2. Training of personnel in selected health units in the use of the guidelines. 3. Field testing of the guidelines for a period of 5 months. 4. Evaluation workshop. 5. Second National Consensus Seminar. Results and Conclusions: 1. The guidelines were applicable in the field and were mostly used by nurses and medical assistants. 2. Restriction of the number of drugs was difficult because of the multiple complaints of the patients: 24; of the patients received more than 3 different drugs. 3. Most conditions were easily managed but for chronic diarrhoea only 40of the health workers adhered to the treatment guidelines. 4. Further training with regular evaluation is required in the use of the guidelines