The effects of aggregation, protein binding and cellular incorporation on the photophysical properties of benzoporphyrin derivative monoacid ring A (BPDMA)

This case report describes a 38-year-old male who was hospitalized for further clarification of clinically mild hyperthyroidism. His increased total hormone levels, the elevated free thyroid hormones and the elevated basal TSH with blunted response to TRH strongly suggested a pituitary adenoma with inappropriate TSH incretion. Transmission computed tomography showed an intrasellar expansion, 16 mm in diameter. The neoplastic TSH production was confirmed by an elevated alpha-subunit and a raised molar alpha-sub/ATSH ratio. However, T4 distribution on prealbumin (PA, TTR), albumin (A) and thyroxine binding globulin (TBG) showed a clearly increased binding to PA (39%), indicating additional prealbumin-associated hyperthyroxinemia. The absolute values of PA, A and TBG were within the normal range. After removal of the TSH-producing adenoma, basal TSH, the free thyroid hormones and T4 binding to prealbumin returned to normal. Therefore, the prealbumin-associated hyperthyroxinemia had to be interpreted as a transitory phenomenon related to secondary hyperthyroidism (T4 shift from thyroxine binding globulin to prealbumin) rather than a genetically conditioned anomaly of protein binding.

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Die Anämie bei malignen Tumorerkrankungen

Nuklearmedizin ◽

10.1055/s-0038-1629491 ◽

1989 ◽

Vol 28 (05) ◽

pp. 193-200 ◽

Cited By ~ 1

Author(s):

E. Aulbert

Keyword(s):

Cellular Uptake ◽

Tumor Tissue ◽

Malignant Tumors ◽

The Other ◽

Novikoff Hepatoma ◽

Cellular Accumulation ◽

Tumor Mass ◽

Proliferation Activity ◽

Morris Hepatoma ◽

Cellular Incorporation

Cellular uptake of 67Ga-labelled transferrin by the tumor tissue was studied in rats with tumors of different malignancy and different tumor mass using the slowly growing Morris hepatoma 5123C, the moderately growing Novikoff hepatoma and the very fast and aggressive Yoshida hepatoma AH130. The cellular accumulation of 67Ga-transferrin was found to correlate with the proliferation activity of the tumor. The 67Ga-transferrin concentration in the very fast growing Yoshida hepatoma was 4.8 times higher than the concentration in the slowly growing Morris hepatoma. The uptake of 67Ga-transferrin by the tumors resulted in a faster disappearance of circulating 67Ga-transferrin from the blood. The rate of disappearance correlated with the proliferation activity and the spread of the tumors. Using tumors of identical size the elimination of 67Ga-transferrin from the blood was much faster in the rats with Yoshida hepatoma than in those with the slowly growing Morris hepatoma. On the other hand, using tumors of different tumor size it could be demonstrated that the rate of disappearance of 67Ga-transferrin from the blood correlated directly with tumor mass. It is concluded that cellular incorporation of transferrin within the tumor cells results in a loss of circulating transferrin, which correlates with tumor mass and proliferation of tumor. This mechanism is supposed to be the cause for the hypotransferrinemia seen in patients with malignant tumors.

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Absorption, Metabolic Stability and Protein Binding Properties of Sutherlandioside B from Sutherlandia frutescens

Planta Medica ◽

10.1055/s-2008-1075256 ◽

2008 ◽

Vol 74 (03) ◽

Author(s):

VLM Madgula ◽

B Avula ◽

X Fu ◽

XC Li ◽

TJ Smillie ◽

...

Keyword(s):

Protein Binding ◽

Metabolic Stability ◽

Binding Properties ◽

Sutherlandia Frutescens

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INCORPORATION OF IODIDE INTO ORGANIC COMPOUNDS IN THE GUINEA PIG THYROID

Acta Endocrinologica ◽

10.1530/acta.0.0430110 ◽

1963 ◽

Vol 43 (1) ◽

pp. 110-118 ◽

Cited By ~ 2

Author(s):

R. Ekholm ◽

T. Zelander ◽

P.-S. Agrell

Keyword(s):

Guinea Pig ◽

Protein Binding ◽

Organic Compounds ◽

Guinea Pigs ◽

Microsomal Fraction ◽

Thyroid Tissue ◽

Particulate Fraction ◽

Supernatant Fraction ◽

Hydrolysis Of

ABSTRACT Guinea pigs, kept on a iodine-sufficient diet, were injected with Na131I and the thyroids excised from 45 seconds to 5 days later. The thyroid tissue was homogenized and separated into a combined nuclear-mitochondrial-microsomal fraction and a supernatant fraction by centrifugation at 140 000 g for one hour. Protein bound 131iodine (PB131I) and free 131iodide were determined in the fractions and the PB131I was analysed for monoiodotyrosine (MIT), diiodotyrosine (DIT) and thyroxine after hydrolysis of PB131I. As early as only 20 minutes after the Na131I-injection almost 100% of the particulate fraction 131I was protein bound. In the supernatant fraction the protein binding was somewhat less rapid and PB131I values above 90% of total supernatant 131I were not found until 3 hours after the injection. In all experiments the total amount of PB131I was higher in the supernatant than in the corresponding particulate fraction. The ratio between supernatant PB131I and pellet PB131I was lower in experiments up to 3 minutes and from 2 to 5 days than in experiments of 6 minutes to 20 hours. Hydrolysis of PB131I yielded, even in the shortest experiments, both MIT and DIT. The DIT/MIT ratio was lower in the experiments up to 2 hours than in those of 3 hours and over.

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EVALUATION OF TISSUE STEROID BINDING IN VITRO

Acta Endocrinologica ◽

10.1530/acta.0.068s223 ◽

1971 ◽

Vol 68 (1_Suppl) ◽

pp. S223-S246 ◽

Cited By ~ 2

Author(s):

C. R. Wira ◽

H. Rochefort ◽

E. E. Baulieu

Keyword(s):

Protein Binding ◽

Binding Sites ◽

Experimental System ◽

Specific Protein ◽

Coupling Mechanism ◽

Target Tissue ◽

Protein Binding Sites ◽

Definition Of ◽

Hormone Specificity

ABSTRACT The definition of a RECEPTOR* in terms of a receptive site, an executive site and a coupling mechanism, is followed by a general consideration of four binding criteria, which include hormone specificity, tissue specificity, high affinity and saturation, essential for distinguishing between specific and nonspecific binding. Experimental approaches are proposed for choosing an experimental system (either organized or soluble) and detecting the presence of protein binding sites. Techniques are then presented for evaluating the specific protein binding sites (receptors) in terms of the four criteria. This is followed by a brief consideration of how receptors may be located in cells and characterized when extracted. Finally various examples of oestrogen, androgen, progestagen, glucocorticoid and mineralocorticoid binding to their respective target tissues are presented, to illustrate how researchers have identified specific corticoid and mineralocorticoid binding in their respective target tissue receptors.

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EVALUATION OF A SIMPLIFIED METHOD FOR DETERMINING SERUM THYROXINE BY COMPETITIVE PROTEIN BINDING ANALYSIS

Acta Endocrinologica ◽

10.1530/acta.0.0640630 ◽

1970 ◽

Vol 64 (4) ◽

pp. 630-636 ◽

Cited By ~ 8

Author(s):

Stephen C. Thorson ◽

Ronald Tsujikawa ◽

James L. Brown ◽

Robert T. Morrison ◽

Hamish W. McIntosh

Keyword(s):

Protein Binding ◽

Clinical Application ◽

Thyroid Status ◽

Serum Thyroxine ◽

Binding Analysis ◽

Simplified Method ◽

Competitive Protein Binding ◽

Hypothyroid Patients

ABSTRACT Serum thyroxine concentrations were determined in 66 euthyroid, 30 hyperthyroid and 13 hypothyroid patients using both the established Murphy method and a simplified method of competitive protein binding analysis. A diagnosis compatibility of 96% was found with both methods indicating that the simplified method has comparable clinical application as an initial screen of thyroid status.

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AN IMPROVED METHOD FOR THE ASSAY OF PROGESTERONE BY COMPETITIVE PROTEIN BINDING

Acta Endocrinologica ◽

10.1530/acta.0.0630225 ◽

1970 ◽

Vol 63 (2) ◽

pp. 225-241 ◽

Cited By ~ 12

Author(s):

B. D. Reeves ◽

M. L. A. de Souza ◽

I. E. Thompson ◽

E. Diczfalusy

Keyword(s):

Protein Binding ◽

Binding Sites ◽

Entire Range ◽

Improved Method ◽

Plasma Progesterone ◽

Extraction And Purification ◽

Corticosteroid Binding Globulin ◽

Competitive Protein Binding ◽

The Individual ◽

Range Of Values

ABSTRACT An improved method for the assay of plasma progesterone by competitive protein binding is described. The improvement is based upon rigorous control of the variables, the compensation for and standardisation of interfering factors inherent in the method and the use of a human corticosteroid binding globulin, that meets the requirements for sensitivity at levels of 1.0 ng of progesterone and below. The assessment of the reliability of the individual steps in the method as well as that of the complete method is presented. The sensitivity of the method is around 0.2 ng progesterone per ml plasma. Accuracy was measured by adding progesterone in amounts ranging from 0.0 to 1.0 ng to 1.0 ml plasma. There was a linear relationship between the progesterone added and recovered throughout the entire range of values, with a coefficient of correlation (r) of 0.94. Of 52 related steroids tested, none was found which would remain associated with progesterone following extraction and purification and which would also compete with progesterone for binding sites.

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RELIABILITY CRITERIA FOR SATURATION ANALYSIS OF STEROIDS BY COMPETITIVE PROTEIN BINDING

Acta Endocrinologica ◽

10.1530/acta.0.065s061 ◽

1970 ◽

Vol 65 (1_Suppl) ◽

pp. S61-S78 ◽

Cited By ~ 3

Author(s):

Billy D. Reeves ◽

David W. Calhoun

Keyword(s):

Protein Binding ◽

Assay Method ◽

Statistical Control ◽

Protein Binding Assay ◽

Competitive Protein Binding Assay ◽

System 2 ◽

Competitive Protein Binding ◽

Single Method ◽

Assay Design ◽

Proper Perspective

ABSTRACT This communication is an attempt to delineate and define reliability criteria for saturation analysis of steroids by competitive protein binding assay. The discussion of these criteria evolved from three major considerations of assay method that help to place the ultimate criterion of accuracy in proper perspective. These major considerations are: 1) the measurement system, 2) the assay design and 3) the calculations and statistical control. Such an approach permits an evaluation, both relative and absolute, for a single method or for multiple methods.

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