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M Christ-Crain

Publications and source records attributed to M Christ-Crain.

5 recordsLinked to original sources
PubMed2004

Comparison of different methods for the measurement of serum testosterone in the aging male.

BACKGROUND: Circulating testosterone (T) levels, mainly non-SHBG bound fractions, decline with advancing age. Free (FT) and bioavailable (BT) testosterone levels have been suggested to represent more reliably the bioactive hormone at the tissue level as compared to total testosterone (TT) levels. However, there is an ongoing controversy as to which T assay is most appropriate in defining T deficiency in the aging male. METHODS: In a prospective observational study, TT, FT and BT levels were measured in 51 elderly men (55 to 70 years). TT levels were determined on two different days using 2 different assays. FT was calculated using TT, albumin and SHBG levels as well as measured directly by radioimmunoassay. The free androgen index (FAI) was calculated using the formula 100 x TT/SHBG. BT was obtained by precipitation of SHBG-bound T with ammonium sulphate. RESULTS: We found good correlations within different assays for TT (r = 0.87 to 0.91, p <0.001) and between TT and calculated FT (r = 0.66 to 0.84, p <0.001). In contrast, the correlation between TT and BT was poor (r = 0.17 to 0.19, p = ns). TT was equivalent to calcFT and was better in mirroring clinical sings of androgen deficiency in elderly men as compared to BT. The intra-individual day-to-day variance of TT levels was 14.8% (range 0.1-79%) with a coefficient of variance of 12.6%. CONCLUSION: Serum TT and the calculated FT fraction correlated well with each other and were superior in defining a group of elderly men with suspected androgen deficiency. In contrast, FT measured by direct RIA and BT reflected gonadal function poorly. Our data favour the repetitive use of TT when screening for androgen deficiency in elderly men.

Aged↗
PubMed2004

Radioiodine therapy in hyperthyroidism: inverse correlation of pretherapeutic iodine uptake level and post-therapeutic outcome.

BACKGROUND: High iodine uptake levels are widely accepted as a condition for successful treatment with radioiodine (RAI). However, the existing data are controversial and the correlation of pretherapeutic RAI uptake level and outcome of RAI therapy has not yet been quantified. The aim of this study was to analyze the influence of RAI uptake on the outcome after RAI treatment and to estimate uptake-dependent success rates. MATERIALS AND METHODS: We retrospectively analyzed 229 patients (m = 53, f = 176; age 64 +/- 14 years) suffering from toxic adenoma, multinodular goitre or Graves' disease, respectively. Clinical status and T3, fT4 and TSH levels were assessed 3, 6, 12 and 18 months after treatment. Successful treatment was defined as loss of hyperthyroidism 18 months after radioiodine therapy. Logistic regression was used to assess the relation between the maximum iodine uptake and the rate of success and hypothyroidism, respectively, after RAI treatment. RESULTS: Overall, patients presented with pretherapeutic RAI uptake values between 17% and 100%. Eighteen months after RAI treatment, an euthyroid state was achieved in 136 patients (60%), hypothyroidism occurred in 47 patients (20%) and 46 patients (20%) remained hyperthyroid. The patients with the lowest pretherapeutic RAI uptakes showed the highest success rates. The overall success rate significantly decreased from 92% at low RAI uptakes to 57% at high uptakes (P = 0.002). This effect was found in the patients suffering from multinodular goitre as well as in the patients with Graves' disease. CONCLUSION: In contrast to the current opinion, our results provide evidence that the pretherapeutic iodine uptake level and post-therapeutic outcome are inversely correlated.

Adenoma↗
PubMed2002

Basal TSH levels compared with TRH-stimulated TSH levels to diagnose different degrees of TSH suppression: diagnostic and therapeutic impact of assay performance.

BACKGROUND: The estimated prevalence of endogenous subclinical hyperthyroidism varies from 4% to 6% and a basal thyroid stimulating hormone (TSH) level < 0.5 mU L-1 may be associated with increased mortality in subjects over 60 years of age who are not on thyroid medication. Exogenous TSH suppression is a mainstay in the treatment of thyroid cancer. Because of recent concerns about potential adverse effects, especially of endogenous TSH suppression on bone, the cardiovascular system and cognitive functions, subclinical hyperthyroidism obtained new clinical importance. We therefore re-evaluated the diagnostic value of basal and thyrotrop in TRH-stimulated serum TSH measurements using TSH assays with different sensitivities. MATERIALS AND METHODS: A total of 805 oral and nasal TRH stimulation tests were performed on 409 ambulatory subjects with low basal serum TSH concentrations of less than 0.1 mIU L-1. Basal serum TSH was measured either using a second generation assay (functional sensitivity > 0.03 mIU L-1) or two third generation assays (functional sensitivity 0.01 mIU L-1 and 0.007 mU L-1, respectively). Serum TSH concentration was determined before and 3 h after oral administration of 40 mg of TRH and before and 30 min after nasal administration of 2 mg of TRH. RESULTS: In the oral testing group, the basal TSH levels measured by the different TSH assays were 0.06 +/- 0.03, 0.04 +/- 0.02 and 0.03 +/- 0.02, respectively, whereas the peak TSH levels were 0.4 +/- 0.6, 0.4 +/- 0.6 and 0.3 +/- 0.5 in the patients with subclinical hyperthyroidism. In overt hyperthyroidism, the basal TSH levels were 0.06 +/- 0.02, 0.03 +/- 0.02 and 0.03 +/- 0.02, whereas the peak TSH levels were 0.19 +/- 0.3, 0.16 +/- 0.3 and 0.15 +/- 0.2, respectively. Basal TSH values could discriminate between different degrees of TSH suppression if measured with a third generation assay (P < 0.001), but not with a second generation assay. There was only a weak correlation between basal TSH and peak TSH when measured by a second generation assay (n = 126; r = 0.3; P < 0.001) in contrast to the strong correlation found using the third generation assays (n = 128; r = 0.7; P < 0.001 and n = 69; r = 0.8; P < 0.001, respectively). CONCLUSIONS: In view of the recent concerns about potential adverse effects in TSH suppression and based on our data, it is mandatory to select a TSH assay with a functional sensitivity of < or = 0.01 mIU L-1 for optimal titration of L-T4 suppressive therapy, especially in patients with thyroid cancer. If, however, only a second generation TSH assay is available, additional TRH testing allows a more careful titration of suppressive thyroxine therapy.

Administration, Intranasal↗