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P C Scriba

Publications and source records attributed to P C Scriba.

At least 109 records · Page 6Linked to original sources
PubMed1980

Comparison of four different algorithms for the calculation of radioimmunoassay standard curves.

Standard curves from 150 determinations of 10 different hormone radioimmunoassays have been evaluated using the following four procedures: logit transformation as performed by Rodbard, Healy's 4-component-logit, spline approximation and a linear interpolation program. The results, calculated by computer, have been compared with manual analysis as the refernce method. The influece of various correction factors has been studied by artificial insertion of outliers. Approximately two thirds of all investigated curves could be calculated with almost equal success using all 4 methods. In calculating the remaining third of the standard curves, each method showed characteristic errors which depended upon the reliability of the assay data and the kind of outliers. The results suggest that the smoothing by spine function is the most flexible method in approximating a radioimmunoassay standard curve. In comparison with the other methods it is less influenced by random errors and fits the characteristic and symmetry of the ideal curve most exactly. The 4-component logit which has been extended by data screening is an improvement of the original logit transformation. Certain reservations exist, however, in elimination of outliers because of the dispersion of the data points, and also because of the arbitrarily set thresholds.

Mathematics↗
PubMed1980

[Development of a radioimmunoassay for thyrotropin (TSH) in dried blood spots together with a comparison of 7 commercial kits (author's transl)].

The blood-spot thyrotropin RIA for detection of congenital hypothyroidism has been established as a screening programme. This article describes the problems in hand, namely optimisation of the method and a comparison of the performance in 7 commercial kits on the West German market. The following factors have been investigated: a. Shelf-life of standards and samples b. Effect of filter paper quality and weight c. Size of paper disc d. Blood sampling time e. Time of removal of paper disc f. Effect on the results of washing the precipitate. The commercial kits at present on the market differ widely in method and price. Apart from this, there was no agreement between the results obtained, and the difference between the standard concentration given by the firm compared with the reference standard MRC 68/38 varied from 22--185%. Methodological guidelines and quality control measures, both internal and external, are suggested.

Blood Specimen Collection↗
PubMed1979

[Validity of scintigraphic and endocrinological methods in classifying autonomous adenomas of the thyroid (author's transl)].

The validity of various scintigraphic and endocrinological methods was assessed in order to classify confirmed autonomous adenomas (AA) and to differentiate AA from euthyroid and hyperthyroid goitres. Methods used included: Measurement of 131J-uptake 6, 24 and 48 hours after 131J-application, before and after suppression by T3, thyroid scanning, count-rate measurement in the AA and the paranodular tissue, and determination of T4. All patients received 131J-therapy (40,000 rads). In 8 out of 30 scintigraphically compensated autonomous adenomas (CAA) there was no TSH response to TRH. 12 cases showed a subnormal TSH response and 10 patients had a normal TSH response. T4-values were increased in only 2 cases. Out of 73 decompensated autonomous adenomas (DAA), 66 cases (90%) had no TSH response and 7 cases showed only a subnormal response. In 48% of DAA T4-levels turned out to be in the hyperthyroid range. Both, scintigraphic and endocrinological tests were found to agree in most cases of DAA. However, the diagnosis of CAA could only be proved on the basis of a scintigraphically confirmed suppressive effect of T3 on the paranodular tissue. Thus, in the individual case, separation of CAA from DAA turned out to be impossible using the results of TRH-test alone.

Adenoma↗
PubMed1979

Improvement of the calcitonin radioimmunoassay.

A rapid and specific assay for human serum calcitonin is described. The total assay-time is under 24 h and uses double-antibody in combination with polyethylene glycol to separate bound and free hormone. The antibody has been checked for its affinity to human serum calcitonin by using a Scatchard plot. Geometric dilution of sera from patients with medullary thyroid carcinoma showed a linear relationship with measured values approximating those expected. The use of Florisil to extract human serum calcitonin from sera to make "human calcitonin-free"-serum for standards has been investigated. A series of 52 normal volunteers and 99 patients with medullary thyroid carcinoma or other possible calcitonin-metabolism disorders have been examined. Only the medullary thyroid carcinoma-patients showed significantly elevated results. In the other groups two patients with phaeochromocytoma and one patient from 29 with bronchial carcinoma had elevated serum calcitonin levels.

Calcitonin↗
PubMed1979

A rapid and specific method for separation of bound and free antigen in radioimmunoassay systems.

This communication reports a method for increasing the speed of separation of bound and free antigen in radioimmunoassay systems with no loss in the specificity of binding. The technique uses a mixture of second antibody and polyethylene glycol. It is not species or antibody specific, and systems using specific first antibodies from rabbit, goat or sheep are all functional. Results for the assay of parathyrin, calcitonin and corticotropin are described here, although the system has been shown to work for triiodothyronine, thyroxin, thyrotropin, thyroxine binding globulin and transferrin. The time taken for the reaction between first and second antibody is in the order of seconds, and the stability of the complex is unchanged over a period of hours.

Adrenocorticotropic Hormone↗
PubMed1979

Effects of obesity, total fasting and re-alimentation on L-thyroxine (T4), 3,5,3'-L-triiodothyronine (T3), 3,3',5'-L-triiodothyronine (rT3), thyroxine binding globulin (TBG), cortisol, thyrotrophin, cortisol binding globulin (CBG), transferrin, alpha 2-haptoglobin and complement C'3 in serum.

UNLABELLED: The effects of total fasting for 31 +/- 10 days followed by re-alimentation with an 800 calorie diet on thyroid function, i.e. T4,T3,rT3,RT3U (resin T3 uptake), and TSH, and on TBG levels in serum were studied sequentially in obese hospitalized patients (N=18). Additionally, cortisol, growth hormone, prolactin, parathyrin and free fatty acids were followed as hormonal and metabolic parameters, respectively. Further, CBG, transferrin, alpha 2-haptoglobin and complement C'3 were measured as representatives of other serum proteins. Results before fasting: T4, T3, TBG, cortisol, CBG, alpha 2-haptoglobin and complement C'3 of the obese patients were elevated when compared with healthy normal weight controls, whereas rT3, T4/TBG ratio, T3/TBG ratio, TSH, coritsol/cbg ratio, growth hormone, prolactin, parathyrin and transferrin of the obese group were normal. RT3U and fT4 index were decreased in the obese patients. Results during fasting: Significant decreases were observed during fasting for the following parameters -- T3, TBG, T3/TBG ratio, transferrin, alpha 2-haptoglobin complement C'3. rT3, T4/TBG ratio, RT3U, fT4 index and FFA increased. T4, tsh response to TRH stimulation, cortisol, CBG, cortisol/cbg ratio, parathyrin, growth hormone and prolactin did not change. Results during re-alimentation: T3, TBG, T3/TBG ratio, TSH response to TRH, transferrin, alpha 2-haptoglobin and complement C'3 increased. Conversely, fT3, RT3U, FFA, cortisol and cortisol/cbg ratio decreased whereas the other parameters did not change. CONCLUSIONS: 1) There is no evidence for primary hypothyroidism in obese patients during prolonged fasting and re-alimentation. 2) The rapid decrease of T3 and increase of RT3U after initiation of fasting are not fully explained by the observed slower decreases in TBG. 3) The alterations of T3, rT3 and RT3U resemble in their kinetics the changes in FFA levels. 4) Fasting reduced the levels of only certain serum proteins, interestingly TBG, transferrin, alpha 2-haptoglobin and complement C'3, all of which, except transferrin, are elevated in obesity. 5) The magnitude of the observed decreases does not suggest any clinically relevant deficiencies in serum proteins. 6) Re-alimentation reverses rapidly all observed changes.

Adult↗
PubMed1979

Isolation, characterization and radioimmunoassay of corticosteroid-binding globulin (CBG) in human serum -- clinical significance and comparison to thyroxine-binding globulin (TBG).

Isolation of the corticosteroid-binding globulin CBG was achieved by 5 chromatographical steps on cortisol Sepharose, QAE-Sephadex A-50, Con A-Sepharose and hydroxylapatite. The purity of the isolated CBG was demonstrated in polyacrylamide gel electrophoresis, SDS electrophoresis, immunodiffusion and ultracentrifugation. Microheterogeneity was shown in isoelectric focusing by 5 bands in the pH range of 3.7--4.2, which could be reduced to one major band after neuraminidase treatment. The equimolar binding of cortisol to CBG was demonstrated by binding studies. The association constant for cortisol was 2.8 x 10(8)M-1, for progesterone 1.7 x 10(6)M-1. From analytical ultracentrifugation, the molecular weight was calculated on 50 700; the sedimentation coefficient was 3.6 S, the partial specific volume 0.690 ml/g, the Stokes radius 38 A and the frictional coefficient ratio 1.5. A specific radioimmunoassay for CBG was established using the purified CBG for immunization, radioiodination and for calibration standards. The normal range of CBG levels in human serum was 2.4--4.4 mg/100 ml (mean +/- 2 SD). Studies were performed to compare the levels of CBG and thyroxine-binding globulin (TBG). No sex differences but a significant biphasic age dependence were observed for both proteins. In pregnancy and under oestrogen treatment of women and men, CBG was demonstrated to be the more distinct indicator of oestrogenic activity as compared with TBG, whereas the sensitivity of TBG was more pronounced to supposedly antioestrogenic substances like Danazol, and in severe disease. No coincidence of genetic CBG and TBG deficiencies have been found so far.

Amino Acids↗
PubMed1978

Treatment of patients with prolactinomas.

Fifty-one female patients with prolactin producing tumors (PRL 1100 to 88,000 microU/ml) and 26 male patients with prolactin producing tumors (PRL 6500 to 400,000 microU/ml) were studied. Only 25% of the females had visual field defects which were present in 70% of the males. All females had amenorrhea but only 35 had galactorrhea. Hypopituitarism was rarely seen in the females but in most of the male patients. Twenty-four females and all male patients were operated (transphenoidal or transfrontal operation). PRL normalized in only eight females and in none of the males. Two patients became pregnant postoperatively, four after postoperative treatment with bromocriptine. Bromocriptine induced regular menses in 4 other patients operated by transsphenoidal route. Eight patients with microadenoma (PRL less than 4000 microU/ml) were treated with bromocriptine alone of whom two became pregnant. The males were also treated with bromocriptine leading to a significant fall of the PRL level accompanied by improvement of libido, sexual potency and headache. Two patients received radiation postoperatively, which led to a fall of PRL and improvement of visual fields. Since PRL levels remained low after withdrawal of bromocriptine for several months an antiproliferative effect of this drug is suggested. Thus differential therapy of PRL producing tumors is possible: In females selective neurosurgery can alone or combined with medical therapy normalize PRL secretion and ovarian function. In patients with microadenoma bromocriptine alone can be successful. In patients with inoperable large tumors radiation should be advocated. Additional bromocriptine therapy may be helpful to stop tumor growth and alleviate the effects of hyperprolactinemia.

Adenoma↗
PubMed1978

Increased secretion of growth hormone, prolactin, antidiuretic hormone, and cortisol induced by the stress of motion sickness.

The stress of motion sickness was experimentally provoked by Coriolis effect. Significant and reproducible increases from the basal serum level (delta mean +/- S.E.) of antidiuretic hormone delta - ADH: 48.2 +/- 4.6 pg/ml; p less than 0.0005), of growth hormone (delta - hGH: 10.0 +/- 1.2 ng/ml; p less than 0.0005), of prolactin (delta - hPRL: 186.5 +/- 29.9 muU/ml; p less than 0.0005), and of cortisol (delta - F; 12.3 +/- 0.9 microgram%; p less than 0.0005) were observed, whereas the luteinizing hormone levels did not change significantly. The stimulation of hormone secretion induced by different degrees of motion sickness seems to correlate with the severity of motion sickness. The secretion of antidiuretic hormones is the most sensitive indicator for the stress of motion sickness whereas growth hormone, prolactin, and cortisol responses to the stress of motion sickness are more delayed and less pronounced.

Blood Glucose↗
PubMed1978

Increased urinary excretion of triiodothyronine (T3) and thyroxine (T4) and decreased serum thyreotropic hormone (TSH) induced by motion sickness.

We exposed 35 male subjects to a rotary chair and motion sickness was provoked by Coriolis effect. This stress caused an increased excretion of urinary T3 and T4 and a decrease of TSH levels in serum. The increment in urinary excretion of thyroid hormones may serve as a very useful measure for the quantitation of physical stress. Although no statistically significant change of T3, T4, and TBG levels in serum could be observed by the employed techniques, the hypothesis is favoured that motion sickness probably causes an immeasurably small increase of the free thyroid hormone fraction in serum, thereby increasing urinary excretion of T3 and T4 and, in turn, decreasing TSH secretion. Physical or psychological stress situations involve most of the endocrine systems. Contadictory results have been reported in the literature concerning the relationship between thyroid function and stress.

Epinephrine↗