W. G. Wood

The Development of a Direct Homologous Radioimmunoassay for Serum Cortisol

This article describes the synthesis of a pure cortisol-3-(O-carboxymethyl) oxime with its subsequent use in producing highly specific antibodies and a 125I-tracer with a shelf life in excess of several weeks. An assay was developed using a pH of 4, thus allowing a direct measurement of cortisol in serum without extraction or heat denaturation. The quality-control parameters were checked - the intra-assay C.V. in the working range (area of clinical interest) was under 5%, and the interassay C.V. under 11%. Correlation studies with results using other antisera and with 3H-tracer are highly significant with the slope of the regression curve deviating less than 2% from the ideal volume. Finally the assay is fully automatable and is suitable for most automatic pipetting and analysis systems.

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.

Iodine deficiency, hypothyroidism, and endemic goitre in Southern Tanzania* A survey showing the positive effects of iodised oil injections by TSH determination in dried blood spots

The Ukinga and Uwanji regions, located in the southern highlands of Tanzania, were studied for the degree of iodine deficiency and the incidence of goitre and hypothyroidism, respectively. A urinary iodine excretion as low as 17.6 +/- 9.3 micrograms/g creatinine was observed in Wangama village. The mean goitre prevalence in 27 villages in Uwanji ranged between 65 and 96% (n = 3031 schoolchildren). Of 681 pregnant women from Ukinga 79.6% had goitre. The prevalence of cretinism as estimated on clinical criteria was 3% in Magoye (Uwanji). A normal serum TSH (below 2.1 mU/l) was observed in only 12 out of 66 school children before iodine prophylaxis, whereas the T4/TBG ratio was decreased in 36 of 63 cases. Blood spot TSH levels in newborn infants (n = 219) from mothers without iodine supplementation were above 12 mU/l in 45%. In contrast, only 20.3% of the newborn (n = 118) had elevated blood spot TSH (p less than 0.002) when the mothers had received an iodised oil injection during pregnancy. Most of the newborn (n = 18; 75%) of the latter group with elevated TSH (n = 24) came from mothers who had received the iodine injection only 1-25 days before delivery. Maternal iodine prophylaxis in late pregnancy does not increase the rate of neonatal hypothyroidism. Conclusions: It has been confirmed that severe iodine deficiency resulting in endemic goitre, cretinism, and hypothyroidism is prevalent in the regions studied. Dried blood spot TSH determinations may serve as an index for the efficiency of iodine prophylaxis programmes. Such a programme was carried out with relatively little expenditure and effort on a large scale basis.

An External Quality Control Survey (EQCS) for Serum Cortisol

The external quality control survey (EQCS) was based on those already published from this department (Marschner, I. et al. (1976) J. Clin. Chem. Clin. Biochem. 14, 345-351; Marschner, I. et al. (1974) Horm. Metab. Res. 6, 293-296; Horn, K. et al. (1976) J. Clin. Chem. Clin. Biochem. 14, 353-360). Each participant received 20 sera sent in dry-ice by express post or airmail, together with a detailed questionnaire requesting assay details and raw data from his own standard curve as well as from the 20 samples.

A second external quality control survey (EQCS) for serum triiodothyronine (T3) and thyroxine (T4) assays using the "Munich model".

Over 100 laboratories participated in an external quality-control survey (EQCS) for T3 and T4, using the Munich Model as conceived in this laboratory ((1-4): Marschner,!, et al. (1974), Horm. Met. Res. 6, 293-296; Horn,K. et al. (1976), this J. 14,353-360; Marschner J. et al. (1976), this J. 14,345-351; Wood, W. G. et al. (1980), this J. 18, 183-192) and carried out over the past 6 years. Twenty lyophilised serum samples, including independant hidden standard curves for T3 and T4, were dispatched by post together with a detailed questionnaire and full instructions on reconstitution of the samples. The returned data were processed as previously described ((4): Wood, W. G. et al. (1980), this J. 18,183-192) and each participant received a full analysis of his«own data and a set of histogrammes with which he could visually check his performance against other laboratories. An explanatory letter was sent, which explained the computer print-out, the coding of the kits and contained a constructive report of the participants performance and helpful advice as to how to improve the assay if this was necessary.

Non-extractive and specific radioimmunoassay for cortisol: Results using a pure cortisol-C3-derivative for antigen and tracer production

1 General Analytical Chemistry 1.1 Fundamentals, Methods, Apparatus, Reagents, Automation, Data Processing 1.2 Inorganic Analysis (Elements, isotopes, ions, complex compounds) 1.3 Organic Analysis (Elements, functional groups, compounds, structural analysis) 2 Particular Products and Fields of Application 2.1 Inorganic Industrial Products (Metals, reactor materials, salts, oxides, semiconductors, glass, ceramics, building materials, industrial solutions etc.) 2.2 Organic Industrial Products (Coal, petroleum, petrochemical products, plastics, textiles, dyes, detergents, intermediate products, paper, leather, rubber etc.) 2.3 Rocks, Minerals, Soils 2.4 Environmental Matrices (Air, gases, waste gases, water, waste water, solid wastes etc.) 2.5 Agricultural-Technical Products (Fertilizers, plants, feeding-stuffs, wood etc.) 2.6 Foods (Cereals, root crops, oil seeds, fruits, vegetables, animal products, spices, additives, beverages etc.; tobacco and tobacco products)

Glucose-Insulin-Potassium Therapy Guided by a Glucose-Controlled Insulin Infusion System in Acute Myocardial Infarction

A number of hormonal and metabolic alterations have been observed during acute myocardial infarction (AMI): There is a rapid increase of catecholamine and Cortisol secretion; free fatty acid (FFA) serum levels are markedly elevated (Gupta et al. 1969; Januszewicz et al. 1971; Vetter et al. 1974); and insulin secretion may be inappropiately low. These alterations result in a disturbance of glucose utilization, so-called stress hyperglycemia. Moreover, under these conditions and due to the accumulation of free fatty acids in the ischemic myocardium, severe ventricular arrhythmias as well as a progression of myocardial cell damage are likely to occur (Kurien and Oliver 1970; Kurien et al. 1971; Oliver et al. 1968).

Problems in automation of serum cortisol radioimmunoassay

ConclusionsA fully automatable method for the cortisol RIA has been developed which requires no prior extraction using an antibody in an assay-system at pH 4.0. The use of 125I-labelled tracer has abolished the need for scintillation fluid and its attendant quench and radioactive waste problems. The capacity of this method is very high because of the automation. The first clinlinal results have shown that this method is reliable, reproducible and gives comparable values with those from the 3H-assay. The fact that no centrifugation is needed, that 3 samples are counted simultaneously and that the capacity is over 1000 tubes per working day makes this method attractive to a routine laboratory with high through put of serum cortisol samples. From the theoretical stand point, this method is adaptable to almost any commercially available automatlin or semi-automatlin assay system.

Methodische Untersuchungen und Vergleich von 7 kommerziellen Kits zur radioimmunologischen Thyrotropin- Bestimmung aus dem getrockneten Blutstropfen

Zusammenfassung: Zur Untersuchung Neugeborener auf konnatale Hypothyreose hat sich die Thyrotropin-Bestimmung aus dem getrockneten Blutstropfen auf Filterpapier durchgesetzt. Die vorliegende Arbeit untersucht methodische Probleme der Test-Optimierung anhand einer eigenen Methode in Gegenüberstellung zu Testkits. Geprüft wurde die Haltbarkeit der Proben sowie der Einfluß von Papierqualität, Plättchengröße, Entnahmezeitpunkt der Filterplättchen und Waschvorgang des Präzipitats auf das Analysenergebnis. Die zum Zeitpunkt der Untersuchung auf dem Markt befindlichen Kits unterscheiden sich erheblich hinsichtlich Testdauer, methodischem Aufwand, eingesetzter Plättchengröße (entspricht Probenvolumen) und Preis. Abgesehen von diesen formalen Unterschieden bestand keinerlei Übereinstimmung der erzielten Testergebnisse. Gravierende Unterschiede zeigten allein schon die beigegebenen Standardkonzentrationen, was bisher bei keiner Kittestung für andere Hormone in diesem Ausmaß gefunden wurde (Wiederfinderaten von 22 bis 185% zum Vergleichsstandard). Es wird die Erarbeitung gemeinsamer Richtlinien und Qualitätskriterien sowie die Etablierung einer externen Qualitätskontrolle vorgeschlagen.