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Biomedical subjects

R Hehrmann

Publications and source records attributed to R Hehrmann.

54 records · Page 3Linked to original sources
PubMed1977

Studies on circadian variations of plasma TSH, thyroxine and triiodothyronine in man.

To evaluate the existence of circadian variations in thyroid hormone and TSH levels, blood was drawn every 20 min for 24 h in four and for 14 h in one volunteer. Hormones were measured by sensitive radioimmunoassays. TSH: A diurnal rhythmicity could be demonstrated with peaks from 8 p.m. to 2 a.m and a nadir from 7 a.m. to 2 p.m. Superimposed on the diurnal rhythm multiple shortlived fluctuations were observed. Thyroxine: Pooled data showed peak values from 8 a.m. to 12 a.m. and lowest levels from 11 p.m. to 3 a.m. Again, shortlived fluctuations were superimposed on the diurnal rhythm in all instances. Triiodothyronine: Hormone levels were highest from 7 a.m. to 1 p.m. and lowest from 11 p.m. to 3 a.m. Fluctuations in T3 levels were less marked than those of T4. Diurnal variations in hormone levels can be demonstrated in most, but not in all instances. Fluctuations are minor and do not exceed the normal range. Therefore these changes are of no relevance in routine testing of these hormones.

Adult↗
PubMed1976

[A highly sensitive C-terminal specific radioimmunoassay for human parathormone as a routine method (author's transl)].

The basis for the radioimmunoassay of parathormone (PTH) as a routine method is a new sheep antiserum and a labelled PTH stabilised by a modification of the purification technique. The antiserum is obtained by immunisation with pig and cattle parathormone, it is C-terminal specific and is used in the assay in a final dilution of 1:35000. The affinity to human PTH is markedly greater than of the antisera used up to now. Two purification steps of 125J labelled bovine PTH lead to a tracer with a nonspecific binding of approximately 5% which increases to approximately 10% within 6 weeks. All normal sera investigated so far were measurable quantitatively (normal range 0.7 to 2.5 mul/equiv.). The lower sensitivity range was at 0.3 mul/equiv. All patients with chronic renal insufficiency and dialysis patients have an increased PTH concentration (3.9 to greater than 20 mul/equiv.). This also applies to patients with primary hyperparathyroidism (2.9 to greater than 20 mul/equiv.).

Animals↗
PubMed1976

Radioimmunoassay of thyroxine-binding globulin in human plasma.

A highly specific and precise radioimmunoassay for thyroxine-binding globulin (TBG) has been developed. Crossreactivity with albumin and prealbumin was excluded. The normal range in young adults was 0.97 mg/100 ml. In childhood TBG was elevated (1.34 mg/100 ml) also in old age (1.28 mg/100 ml). In normals and in childhood there was a good correlation of TBG with thyroxine (T4). T4 did not correlate with TBG with regard to age. Triiodothyroxine (T3) did not correlate with TBG in any group. T4 and T3 exhibited a progressive decrease with age. No correlation between age and TBG was found. In mild thyrotoxicosis (T3 : 4.5 ng/ml, with normal T4 and negative TRH-test) TBG was slightly increased (1.20 mg/100 ml), whereas in more severe hyperthyroidism (T3 : 6.4 ng/ml, T4 : 16.3 mug/100 ml) TBG concentration was not significantly different from normals. In hypothyroidism TBG was elevated (1.26 mg/100 ml). The conclusion from these data is that TBG does not follow the progressive decrease of T4 and T3 with age. Thus, age-dependent euthyroid ranges for thyroid hormone concentration, including TBG concentration, must be established for better clinical discrimination of thyroid function. Possible dependence of TBG on the nature of thyroid hormone concentration must be considered in the production and peripheral kinetics of thyroid hormones.

Cross Reactions↗
PubMedDate not supplied

Androgen and estrogen response to adrenal and gonadal stimulation in idiopathic hemochromatosis: evidence for decreased estrogen formation.

Gonadal function in idiopathic hemochromatosis (IHC) was evaluated by comparing clinical features and levels of sex hormones in 10 male patients with IHC (cirrhosis, 4; fibrosis, 6), 6 male patients with alcoholic cirrhosis (AC) and 10 healthy, age-matched controls. Impotence was present in 9 IHC and all AC patients and was associated with decreased plasma testosterone levels. However, gynecomastia, a feature in all patients with AC, was not present in IHC, and plasma sex hormone binding globulin was normal. Patients with IHC showed significantly lower basal estradiol levels (17.7 +/- 6.3 pg per ml) than did controls (28.5 +/- 8.5 pg per ml), and low LH levels (p less than 0.01), which were insufficiently stimulated by luteinizing hormone releasing hormone (n = 8) as well as a decrease in prolactin concentration (2.9 +/- 1.4 vs. 5.9 +/- 1.9 ng per ml in the controls) suggesting pituitary failure. Synthesizing capacity of sex hormones was determined by adrenocorticotropic hormone and human chorionic gonadotropin administration. Basal and stimulated levels of androstenedione and cortisol indicated normal function of the adrenals in IHC. However after adrenocorticotropic hormone, estrone levels increased to only 16.2 +/- 8.4 pg per ml (controls, 27.3 +/- 4.7 pg per ml; p less than 0.01). Increments of estrone (12.5 +/- 9.2 pg per ml) and estradiol (17.9 +/- 11.6 pg per ml) were also lower in IHC following human chorionic gonadotropin administration than in controls (26.0 +/- 7.2 and 37.5 +/- 11.4 pg per ml, respectively). In contrast, plasma human chorionic gonadotropin raised testosterone levels 3.3-fold in IHC and 2.2-fold in controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Function Tests↗
PubMedDate not supplied

Homologous radioimmunoassay for human mid-regional parathyroid hormone.

A radioimmunoassay, selective for the clinically important mid region of human parathyroid hormone (hPTH), is reported. The synthetic 44-68 amino acid sequence (h44-68PTH) was used as both the standard and tracer material. This eliminated many of the undesirable characteristics associated with PTH assays the employ hormone of biological origin. These components allowed the detection of mid regional fragments present in both intact and fragmented hPTH, with a working range between 50 and 2500 pg/ml h44-68PTH. There was no interference from serum proteins and no significant cross reactivity to a range of N-terminal, C-terminal and other mid regional hPTH peptides. The assay proved to be rapid (total time 24 h) and was extremely reproducible, with an intraassay and interassay variation of 2.8% and 5.6% respectively (expressed as percentage SE in mean). The plasma concentration of normal subjects was established as 129 +/- 6 pg/ml (h44-68PTH) with a range of 50-300 pg/ml (n = 42). This assay, using fully synthetic hPTH peptides, was able to distinguish between euparathyroid and hyperparathyroid subjects, which suggests that the assay is of diagnostic value.

Amino Acid Sequence↗