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Biomedical subjects

M Büchner

Publications and source records attributed to M Büchner.

At least 19 recordsLinked to original sources
PubMed1986

[Long-term results of Nd-YAG laser iridotomy and indications deriving from it].

Of 132 patients who had undergone Nd-YAG laser iridotomy, 70 were randomly selected for follow-up examinations. Nd-YAG laser iridotomies were subsequently performed on 124 eyes (of these 70 patients), 12 for acute angle-closure glaucoma, 19 fellow eyes of those which had angle-closure glaucoma, 70 for chronic angle-closure glaucoma, and 23 eyes with increasingly narrow chamber angle under miotic therapy. The follow-up period ranged from 1 to 25 months (median = 9 months). Eighty-seven percent of the iridotomies remained visibly open. Of 12 acute glaucomas, 10 were successfully treated, whereas only 2 required a basal iridectomy. In the large group of 106 eyes with a "narrow angle condition," a significant pressure reduction from 20.9 +/- 5.8 to 16.7 +/- 3.4 mm Hg and a significant enlargement of the chamber angle resulted. Since fistulizing procedures involve a risk of malignant glaucoma, Nd-YAG laser iridotomy, which this investigation showed to be risk-free, is the initial procedure of choice in narrow-angle conditions, especially subacute and chronic angle-closure glaucoma, in order to alleviate the angle-closure component in such angle-closure situations, to diagnose its contribution to peak IOP, and to facilitate argon laser trabeculoplasty when needed.

Aged↗
PubMed1982

[Plasma aldosterone in pregnancy, during labor and in the newborn infant].

Plasma aldosterone levels of mother and child during pregnancy were measured by means of radio-immuno assay without chromatography. In cases of unconspicuous pregnancy average aldosterone concentrations were found to increase from 23.2 ng/100 ml in the first trimester to 37.2 ng/100 ml in the second trimester and further to 64.0 ng/100 ml in the third.--High values were recorded from mothers (71.9 ng/100 ml) after birth and from umbilical cord blood of vaginally delivered newborns (83.4 ng/100 ml).--Aldosterone values as low as 60.9 ng/100 ml were recorded from newborns delivered by caesarean section with reduced parturitional stress. These were lower with significance than the levels recordable from newborns after spontaneous vaginal delivery (83.4 ng/100 ml). Values lower with significance were recorded from plasma of pre-eclamptic women in the third trimester (41.9 ng/100 ml).--No difference was found to exist between aldosterone concentrations in umbilico-arterial blood, on the one hand, and those in umbilico-venous blood, on the other.

Aldosterone↗
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

[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↗