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Biomedical subjects

W Hubl

Publications and source records attributed to W Hubl.

At least 55 records · Page 3Linked to original sources
PubMed1981

Enzyme immunoassay and radioimmunoassay for plasma renin activity. I. Comparison of the methods.

Sensitive and specific enzyme and radioimmunoassays have been developed for the determination of renin activity. These methods are based upon the determination of angiotensin I generated by endogenous renin and angiotensinogen. An antibody trapping technique was used, while the addition of chemicals to the plasma, used until now as inhibitors for converting enzyme and angiotensinases, was eliminated. The angiotensin I was labelled with horseradish peroxidase for enzyme immunoassay and with iodine-125 for radioimmunoassay. Antibody bound and free labelled antigen were separated from each other by a second antibody polyethyleneglycol method (enzyme immunoassay) and by charcoal-dextran adsorption (radioimmunoassay). The values of renin activity in human plasma determined by enzyme immunoassay correlated well with those obtained by radioimmunoassay.

Adult↗
PubMed1981

Enzyme immunoassay for plasma renin activity: II. Clinical application.

The application of an enzyme immunoassay for plasma renin activity in clinical diagnosis was studied and the following findings were obtained: 1. In patients with primary aldosteronism, very low renin activities were found. On the other hand, increased renin levels were observed in patients with secondary aldosteronism (renal artery stenosis, malignant hypertension, Bartter's syndrome). 2. Plasma renin activity was found to be considerably increased in Addison's disease. Measurements of Plasma renin were a guide-line for appropriate mineralocorticoid substitution in those patients. In 6 patients with salt-losing congenital adrenal hyperplasia due to 21-hydroxylase deficiency, the renin activity was also elevated and normalized after corticoid treatment. 3. During pregnancy, the renin levels showed an increasing tendency from the first to third trimester. Women with pre-eclampsia showed higher values than normal pregnant women. 4. An age-dependent change of renin activity was observed in newborns and children, especially markedly increased values during the first 5 days of life. 5. During the normal menstrual cycle the renin levels increased to a maximum in the mid-luteal phase. A significant increase of renin activity was found in women taking oral contraceptives. Previously, we reported on the determination of renin activity by an enzyme immunoassay (EIA) (Hubl et al., 1980). In this study, we examined the clinical application of this EIA.

Addison Disease↗
PubMed1979

Study of plasma aldosterone in normal pregnancy, in pre-eclamptic women and in cord plasma of newborns.

A radioimmunoassay without chromatography was used for the determination of plasma aldosterone in pregnancy. The mean values (+/- S.D.) of aldosterone concentration increased consistently from 23.2 +/- 5.3 ng/100 ml (n = 14) during the first trimester to 37.2 +/- 10.6 ng/100 ml (n = 17) during the second trimester and 64.0 +/- 18.8 ng/100 ml (n = 29) during the third trimester of pregnancy. The highest values were found at delivery (71.9 +/- 14.2 ng/100 ml; n = 21) and in the cord plasma of newborns (83.4 +/- 14.9 ng/100 ml; n = 21). Significantly lower plasma aldosterone values were found in the plasma of pre-eclamptic women during the third trimester of pregnancy (41.9 +/- 21.3 ng/100 ml; n = 11).

Aldosterone↗
PubMed1978

Evaluation of a competitive binding assay for cortisol using horse transcortin.

A non-chromatographic competitive binding assay (CBA) using horse transcortin has been employed in the routine measurement of cortisol in plasma, urine and amniotic fluids. Comparing the values with those of a radioimmunoassay (RIA) or a fluorimetric method (FM) an excellent correlation between the three methods both in plasma and urine has been calculated in normal subjects and in patients with various endocrine disorders. In amniotic fluids, however, there were discrepancies between CBA and RIA. Whereas CBA showed no differences, RIA gave significantly higher values in amniotic fluids of female than of male fetuses. Elevated free plasma cortisol levels observed in patients with prostatic cancer after diethyl stilboestrol diphosphate therapy did not correlate with unconjugated urinary cortisol concentration as measured with CBA and FM. In newborns, a relatively high plasma level found 12 hours after birth was followed by a nadir on the 2nd and 3rd day of life and by an increase until levels of adults on the 5th day of life were reached.

Amniotic Fluid↗
PubMed1978

[A radioimmunoassay for plasma 11-desoxycortisol and its use in the rapid metopirone test].

A radioimmunoassay for the measurement of 11-deoxycortisol in plasma is described. Antiserum against 11-deoxycortisol was produced by immunizing rabbits with the 21-hemisuccinate of 11-deoxycortisol coupled to bovine serum albumin. The method does not require chromatography but instead makes use of a simple extraction procedure which, in combination with the antibody characteristics, is relatively specific for the 11-deoxycortisol determination. The smallest amount measurable is 5 pg. The intra-assay coefficient of variation was 6.3% before metopirone and 7.2% after metopirone. The inter-assay coefficient of variation was 12.5% before metopirone and 10.3% after metopirone. Pituitary-adrenal reserve was evaluated in control and hypopituitary subjects by a simple midnight metopirone test.

17-Hydroxycorticosteroids↗
PubMed1978

Plasma aldosterone in newborns and children.

Plasma aldosterone concentrations were determined by radioimmunoassay in 134 healthy newborns and children of both sexes from the first day to 14 years of life. The highest mean value of aldosterone level was found during the first 24 hours of life (79.5 ng/100 ml), with a mean elevation by a factor of 10 in comparison to the results of adults. An age dependent decrease towards the children in the age group 6-14 years was found. The aldosterone concentration of the age group 6-14 years did not differ significantly from the aldosterone level of adults. The question of the origin of the increased aldosterone levels found in newborns and infancy is discussed.

Age Factors↗
PubMed1977

[Demonstration of a new analytical grading system for the determination of pheochromocytoma within the scope of hypertension control].

The problems of the phaeochromocytoma are in its rareness, its appearance--every patient with hypertension can be a carrier of a phaeochromocytoma--, its localisation--10% are situated outside the adrenal glands--, its operability with following permanent normalisation of the pressure. As hypertension is very frequent and the diagnostics is very expensive the finding of carriers of phaeochromocytomas is possible only by means of screening methods. Thus cases with an urgent suspicion are found. Such a method is described, the basis of which is a semiquantitative determination of the vanillic amygdalic acid. Instead of the usually used diazocolour-reagent in connection with a non-optimal buffer a complete nitrophenylantiazotate with a buffer of high ionic strength is taken. The pH-value 10 of the urine which is to be demanded for the colour reaction is thus reached in every case. In order to avoid falsely normal results with every urinary test a preparation with added vanillic amygdalic acid is performed and thus the presence of colour inhibitors is recognized. If the result is pathological a quantitative determination is necessary.

Adrenal Gland Neoplasms↗
PubMed1977

[Radioimmunological determination of aldosterone in the serum. New method for the localization of aldosteronism].

It is described a radioimmunologic method for the determination of aldosterone in the plasma and the urine. The method possesses a high specifity, so that a chromatographic prepurification can be given up. The achieved sensitivity allows an analysis in 0.2 ml plasma. This radioimmunoassay can be used for the determination of the aldosterone concentration in the blood after side-separated taking from the adrenal veins by means of the catheter technique. With this a localisation diagnostics of the aldosteronoma is possible.

Aldosterone↗
PubMed1977

[A specific radioimmunologi determination of plasma estradiol without chromatography during the cycle and in pregnancy and determination of the free non-protein-bound fraction using dialysis].

The plasma concentrations of estradiol were measured by radioimmunoassay without chromatography. The antibody against estradiol was produced in rabbits immunized with 17beta-estra-diol-6-(0-carboxymethyloxime): bovine-serum-albumin. The lower limit of quantitation is 2.6 pg estradiol. A coefficient of variation of 5.9% was ascertained. The recovery of this method is 93% in the range of 89.8 to 95.2%. The concentrations of estradiol during the menstrual cycle are from 30 pg/ml to 300 pg/ml. Estradiol levels during the anovulatory cycle were found below 70 pg/ml. Similar values (2.0 to 2.5%) of percent of unbound estradiol in normal and anovulatory cycle were calculated. The concentrations of estradiol increase in pregnancy on an average of 16 ng/ml. The percentage of free estradiol decreases (up to the 24 weeks of pregnancy) from 2.3% to 1.2%.

Dialysis↗
PubMed1976

A direct radioimmunoassay for free aldosterone in urine without extraction and chromatography.

A direct radioimmunoassay for the determination of free (unconjugated) aldosterone in urine has been developed for the clinical laboratory. The method is based on a determination without extraction and chromatography. In comparison with a reference method including extraction and column chromatography on Sephadex LH 20 a highly significant correlation was found. The coefficient of variation was 5.6% for intraassay variability and 10.4% for interassay determinations. In normal adults the average value of the urinary free aldosterone was 190 ng/24 h (range: 60--320 ng/24 h). During sodium restriction, a 3 fold increase in free aldosterone was observed in normal subjects. In patients with adrenal insufficiency, the values were below 60 ng/24 h, and in two patients with Conn's syndrome, the excretion of free aldosterone was 890 and 1040 ng/24 h. The method was found suitable for routine clinical use.

Addison Disease↗
PubMed1976

Free aldosterone concentrations in the urine of newborns.

In 1-day-old infants (24--48 hrs after birth), the free aldosterone excretion in urine was found to be significantly lower as compared to adults. The free aldosterone excretion increased then extensively by factor 11.4 at the age of 1 to 14 days and decreased at the age of 14 to 28 days.

Aldosterone↗
PubMed1975

[Interpretation of the metopirone--midnight-short-test by means of simultaneous determination and evaluation of the increase of 11-deoxycortisol and decrease of plasma 11-hydroxycorticosteroids].

In this paper the clinical and laboratory-chemical methods of a metopiron short test at midnight are described. In addition to this the results after a conceptional metopiron longtime test and a metopiron short test are compared in 40 endocrinologically healthy persons. It was shown that, compared with the long-term test, in the metopiron short test at midnight no reduction of the informations and of the exactness of the results appears. Since the isolated determination of the increase of substance S after metopiron reveals a relatively broad area of distribution in literature the interpretation normal-pathological is problematic. Therefore it is tried to obtain an improved evidence in the test with the help of an interpretation quotient Q which establishes the variables measured in the regulating circle of the adrenocortico-pituitary system (decrease of the 11-hydrocorticosteroid and increase of the 11-desoxycorticosol in the plasma after application of metopiron, r = 0,96 shown a very good correlation of these two sizes). After utilization of the method of interpretation in persons with different diseases of endocrinological and nonendocrinological etiology the results were in every case good classifications into the areas normal, with limiting value and phathological. The classification of the individual clinical pictures with the help of the interpretation mode mentioned is discussed. Finally the advantages and disadvantages of the used method are compiled.

11-Hydroxycorticosteroids↗