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M Hüfner

Publications and source records attributed to M Hüfner.

At least 19 recordsLinked to original sources
PubMed2001

Increase of serum estradiol in cirrhotic men treated by transjugular intrahepatic portosystemic stent shunt.

BACKGROUND/AIMS: Liver cirrhosis is frequently associated with sexual dysfunction and hormonal abnormalities. To evaluate the effect of portosystemic shunting on sex steroid serum concentrations, a prospective study was performed in cirrhotic patients treated consecutively and electively by transjugular intrahepatic portosystemic stent shunt (TIPS). METHODS: In 27 patients with liver cirrhosis we measured serum levels of testosterone (T), sexual hormone binding globulin (SHBG), luteinizing hormone, follicle-stimulating hormone, dehydroepiandrosterone sulfate, androstenedione (A), estradiol (E2), 17-OH-progesterone and the T/SHBG ratio before and 3 months after TIPS. RESULTS: In men (n = 17) 3 months after TIPS, A and E2 significantly increased, with mean serum levels rising from 4.4 +/- 2.5 to 5.6 +/- 2.9 ng/ml (P = 0.04) and from 27 +/- 9 to 40 +/- 19 pg/ml (P = 0.003), respectively. In contrast to A the increase of E2 persisted at 9 and 15 months after TIPS. Erectile dysfunction increased from 30% before TIPS to 70% after TIPS. In women (n = 10) A and E2 levels did not change significantly after TIPS. CONCLUSIONS: TIPS aggravated hormonal dysbalance of sex steroids in favor of estrogens (hyperestrogenism) in men.

Adult↗
PubMed2000

Persistent hypocalcemia with elevated parathyroid hormone levels after long-term primary hyperparathyroidism: report of a case.

We report herein the case of a 48-year-old man with long-term persistent primary hyperparathyroidism (pHPT) despite undergoing a parathyroidectomy in 1976, followed by a reoperation in 1978, for whom resection of a parathyroid adenoma in the upper mediastinum was eventually performed. His postoperative course was complicated by recurrent hypocalcemia refractory to oral calcium substitution and significantly elevated levels of parathyroid hormone (PTH). The radiological findings are presented, and we discuss the possible reasons for the coincidence of severe hypocalcemia with increased PTH levels in association with pHPT.

Adenoma↗
PubMed2000

Disseminated thyroid autonomy or Graves' disease: reevaluation by a second generation TSH receptor antibody assay.

The clinical diagnosis of disseminated autonomy (DISA) can only be established by exclusion of Graves' disease (GD). Both hyperthyroid conditions share the same scintigraphic appearance and can only be distinguished from each other clinically either by the presence or absence of endocrine ophthalmopathy (EO) or thyrotropin (TSH) binding inhibiting immunoglobulins (TBIIs). The purpose of this study was the reevaluation of thyroid autonomies originally classified as DISAs by a second-generation radioreceptor antibody assay (RAA) (DYNOtest TRAKhuman) (B.R.A.H.M.S. Diagnostika, Berlin, Germany). The analysis included 32 patients (female: n = 25, male: n = 7; mean age: 46 +/- 18 years) who were initially diagnosed with DISA. All patients were TSH receptor (TSHR) antibody (TRAb) negative by a conventional radioimmunoassay (RIA) (TSH-REZAK RIA) (Medipan Diagnostica, Selchow, Germany) during their first evaluation. The presence of EO was excluded by clinical signs in all patients. Surgery had been performed prior to our evaluation in 5 patients and after our survey in 1 patient. Four patients had been treated previously with 131I. Ten patients were treated with thionamides during our evaluation, and 13 had not been treated before. One hundred three patients who had either healthy thyroids, nontoxic goiters, or focal autonomies served as controls and were evaluated both by the TSH-REZAK assay and the DYNOtest TRAKhuman assay. Seven of thirty-two (22%) patients originally classified as DISA were TRAb positive in the second-generation assay. In this group, 5 of 7 patients had a total thyroid volume (TTV) <30 mL (positive predictive value [PPW] for TRAb positivity 71%), and 5 of 7 patients had a diffuse goiter (PPW for TRAb-positivity 71%). Six of seven patients were anti-thyroperoxidase (TPO) positive (PPW for TRAb positivity 85%). A hypoechoid pattern on ultrasound was present by visual analysis in 3 of 7 patients (PPW for TRAb positivity 43%). A 100% PPW for TRAb positivity could be obtained if a goiter <30 ml was combined with anti-TPO positivity, but this combination was present in only 4 of 7 (57%) patients. With the second-generation assay, one false positive test result was observed in the control group. Surgery was performed in 6 patients who were TRAb negative in both assays. In all these cases, the histologic findings were compatible with autonomous transformation of the thyroid. Our study demonstrates that a significant number (22%) of patients formerly classified as DISA may actually have GD. However, DISA still exists as a clinical entity, and its pathophysiological link to multifocal and unifocal autonomy should be further investigated.

Adult↗
PubMed2000

[Clinical implications of a new TSH receptor antibody assay (DYNOtest TRAKhuman) in autoimmune thyroid diseases].

AIM: Conventional radioreceptor-antibody-assays (RAAs) fail in the detection of TSH-receptor antibodies (TRAKs) in 10-30% of patients with Graves' disease (GD). The aim of this study was the evaluation of the diagnostic and clinical impact of a new RRA (DYNOtest TRAKhuman) which uses the human recombinant TSH-Receptor in the diagnosis of autoimmune thyroid disease. METHODS: Sera from 142 consecutive patients (GD: n = 50, autoimmune thyroiditis/AIT: n = 92) and from 55 controls (31 patients without any thyroid disease and 14 with euthyroid goiter) were evaluated both with the DYNOtest TRAKhuman-assay and a conventional RRA (TRAK-Assay). Thyroid in vitro parameters and thyroid sonography were performed in all patients. RESULTS: The DYNOtest TRAK-assay was significantly superior to the conventional RRA in the diagnosis of GD (p < 0.00012), especially in those who were treated by thionamides (p < 0.003) and in the diagnosis of TRAK-positive patients with AIT (p < 0.003). The majority of TRAK-positive AIT-patients suffered from hypothyroidism. One false positive result in patients with euthyroid goiter was found in the TRAK-Assay as well as in the DYNOtest TRAKhuman-Assay. Therefore the specificity of the DYNOtest TRAKhuman was not inferior compared with the conventional assay. CONCLUSION: The DYNOtest TRAK-assay is superior in the diagnostic work up of Graves' disease compared with a conventional TRAK-assay and offers an equal specificity.

Female↗
PubMed1999

Development of the osteoblast phenotype in primary human osteoblasts in culture: comparison with rat calvarial cells in osteoblast differentiation.

In rat osteoblast-like cells, a time-dependent sequence of growth and differentiation-dependent genes has been identified and a model of osteoblast differentiation in culture suggested. We investigated the expression of the bone matrix-associated proteins osteonectin and procollagen I and of the bone cell phenotype-related proteins alkaline phosphatase and osteocalcin during cell culture in primary human osteoblast like cells. Primary human explant cultures from nine young healthy donors were established under highly standardized conditions. Cells in the second passage were analyzed on different days from day 1 to 32, comparing cells growing under the influence of ascorbate with controls. Gene expression was determined by Northern blot analysis or polymerase chain reaction. Osteocalcin expression was also investigated after 1,25-(OH)(2)D(3) stimulation. On the protein level, newly synthesized collagen I, alkaline phosphatase activity, and secretion of osteocalcin were analyzed at all time points. On comparing our findings to the pattern of gene expression suggested for the rat calvarial osteoblast system, we found a similar developmental sequence for the so-called "proliferation" as well as a similar, but lengthened, sequence for the "matrix maturation stage." During "matrix maturation," we found an ongoing proliferation despite increased alkaline phosphatase and decreased procollagen I gene expression. Our study, therefore, shows that in pHOB the gene expression profile proceeded to the "matrix maturation stage," as defined by Owen and colleagues, independent of ongoing proliferation. We were unable to observe the mineralization period as demonstrated by the missing increase of osteocalcin expression and lack of nodule formation in our human osteoblast model. In contrast to the rat system, we found a proliferation stimulating influence of ascorbate, suggesting species-specific differences in response to differentiation factors. From these data, we conclude that general considerations on physiology and pathophysiology of bone cell differentiation have to be confirmed in the human osteoblastic cell system.

Adult↗
PubMed1999

1,25 dihydroxyvitamin-D3 attenuates the confluence-dependent differences in the osteoblast characteristic proteins alkaline phosphatase, procollagen I peptide, and osteocalcin.

In the present study a cell culture model of primary human osteoblasts based on degrees of confluence was investigated by measuring basal and 1,25(OH)2D3stimulated levels of the osteoblast characteristic proteins alkaline phosphatase (AP), procollagen I-peptide (PICP), and osteocalcin (OC), as well as the corresponding gene expression. Primary osteoblast-like cell cultures from seven donors were treated in the second passage with 1,25(OH)2D3 (5 x 10(-8) M for 48 hours) and investigated at four stages of confluence (stage I 50%, stage II 75%, stage III 100%, and stage IV 7 days postconfluence). In untreated cultures passing through the different stages of confluence, we saw a 1.8-fold increase of AP activity, a 2. 3-fold increase of OC secretion, but a decrease of PICP levels to 0. 36-fold. Gene expression showed only minor variation between the different confluence stages. 1,25(OH)2D3 did not significantly affect PICP production. Alkaline phosphatase protein was stimulated during proliferation until confluence, with no effect thereafter. Surprisingly, OC secretion and mRNA expression were stimulated in all four stages to the same absolute level independent of basal values. We conclude that our results correspond to other studies showing differentiation-stage dependent changes of basal levels of osteoblast-specific proteins. However, 1,25(OH)2D3 stimulation decreased the confluence-dependent difference for AP and abolished it for osteocalcin, thus leading to a more differentiated phenotype of the osteoblast. Therefore, 1,25(OH)2D3 stimulation might improve the reproducibility of results obtained at different confluence stages from cultures of clinical samples.

Alkaline Phosphatase↗
PubMed1999

Evaluation of procollagen III peptide as a marker of tissue hyperthyroidism in long-term treated women with TSH suppressive doses of thyroxine.

Increased serum concentrations of the aminoterminal propeptide of collagen III (PIIINP) are found in overt hyperthyroidism. Thus, measurement of serum PIIINP might be useful as an early marker of tissue hyperthyroidism in patients with TSH suppressive thyroxine treatment. In a prospective study we evaluated female patients followed in the thyroid outpatient clinic. Serum PIIINP concentrations were analysed in three groups: patients with TSH suppressive thyroxine treatment for more than 6 months (n = 33, TSH < 0.1 mU/l), patients with thyroxine substitution for hypothyroidism for more than 6 months (n = 20, TSH 0.2-4.0 mU/l) and spontaneous hyperthyroid patients (n = 8, TSH < 0.03 mU/l, increased freeT4 and/or T3). Beside TSH, thyroid hormones and serum PIIINP we measured serum SHBG and a clinical score. Hyperthyroid patients had clearly elevated serum PIIINP and SHBG values and a higher clinical score when compared with other study groups (p < 0.001). Patients with TSH suppressive thyroxine treatment had higher fT4 and T3 concentrations than the thyroxine substitution group (fT4 22 +/- 4.8 pmol/l vs. 17 +/- 2.6 pmol/l, T3 2.2 +/- 0.4 nmol/l vs. 1.8 +/- 0.3 nmol/l, p < 0.001) and also elevated serum SHBG values (77.6 +/- 27.5 nmol/l vs. 58.4 +/- 18 nmol/l, p < 0.01). However, serum PIIINP concentrations and the clinical score were very similar in both thyroxine treated groups (PIIINP in TSH suppression group 3.0 +/- 0.67 microg/l vs. 2.8 +/- 0.65 microg/l in the substitution group, clinical score 2 +/- 1.8 pts. vs. 1.7 +/- 1.5 pts. p = n.s.). In conclusion, serum PIIINP is not a reliable early marker for detection of tissue hyperthyroidism in long-term thyroxine treated women with suppressed TSH.

Adult↗
PubMed1998

Analysis of human primary bone cells by fluorescence activated cell scanning: methodological problems and preliminary results.

We describe the development of flowcytometrical methods to analyse human primary osteoblast-like cultures obtained from trabecular bone explants in comparison to the human osteosarcoma cell line HOS 58. Two antigens typical of osteoblasts were studied: bone alkaline phosphatase and collagen/procollagen I; the non-specific attachment protein fibronectin served as control. The morphology of all different antigens is shown by immunocytochemistry before flowcytometrical analysis. The establishment of flowcytometry is described in detail. While all antigens tested were nearly 100% positive in the HOS 58 cells in immunocytochemistry and flowcytometry, in primary osteoblast-like cells results varied widely between both methods. Cell permeabilisation before flowcytometry improved the homogeneity of results, probably by increasing the accessibility of the specific antibody to intracellular compartments. Though up to 80% of cells were lost during preparation the ratio of positive versus negative cells in specific experiment was not dependent on the cell recovery. Therefore, the cells finally analysed seemed to be representative of the total population.

Adult↗
PubMed1998

In vitro differentiation potential of a new human osteosarcoma cell line (HOS 58).

Cultured rodent osteoblastic cells reiterate the phenotypic maturation of osteoblasts seen in vivo. Under appropriate culture conditions this maturation is a stepwise sequence of phenotypic changes culminating in the production of a mineralised matrix. Although individual components of the osteoblast phenotype are apparent in transformed osteosarcoma cell lines, the co-ordination of the maturation sequence appears to be compromised. Because to date no comparable human cell differentiation system has been developed we investigated the recently introduced HOS 58 osteosarcoma cell line up to 3 months in culture. Proliferation, the secretion of osteoblast specific proteins, gene expression and mineralisation were analysed at different time points. Low-density HOS 58 cultures exhibit rapid proliferation and high levels of c-myc, collagen type I and osteopontin mRNAs. This phenotypic stage was maximum between the 4th and 5th days of culture. As cell density increased expression of these genes declined and by day 14 the predominant mRNAs was alkaline phosphatase. Osteocalcin secretion was detected after confluence at an increasing level. In the presence of ascorbate and beta-glycerophosphate the production of alkaline phosphatase and collagen type I increased coincident with the elaboration of a Von Kossa staining matrix. Nevertheless no proper mineralisation of the collagenous matrix was detectable by electron microscopy. Hence, the human osteosarcoma cell line HOS 58 expressed a rather differentiated phenotype with further maturation during a culture period of 21 days. We conclude that the developmental sequence exhibited by the HOS 58 human osteosarcoma cell line is comparable to that described for primary rat osteoblasts. However, in detailed analysis considerable differences to other species are evident. Further evaluation of the HOS 58 system and comparison to other human osteoblast cell lines will be necessary to establish the most appropriate differentiation model for human bone cell cultures.

Adult↗
PubMed1998

The use of confluence stages does not decrease the overall variability in primary human osteoblasts but can give additional information on differentiation in vitro.

Primary cultures of human osteoblast-like cells are frequently used to study osteoblast function. Due to inhomogeneous growth of primary osteoblasts in culture, it is of interest if the use of confluence stages for analysis would reduce the overall variability. Consequently, we have tested the influence of degree of confluence and passage number on the growth and differentiation of human primary osteoblast-like cells. Phenotypic features of primary human osteoblast-like cells were compared at four successive cell densities defined as stage of confluence I (50%), stage II (75%), stage III (100%) and stage IV (5 days post confluence). The stability of the system was also tested by comparing these observations obtained using cells from the 2nd and 4th passages. As a sign for further differentiation, the number of AP-positive cells increased with a decrease in proliferation. The secretion of procollagen-I decreased to 50% during culture while procollagen I mRNA doubled from proliferation to confluence. A constant activity of alkaline phosphatase, procollagen-I secretion and procollagen I gene expression over passages was seen together with a decrease in growth. The paper introduces a potential model of osteoblastic differentiation in vitro for human primary osteoblast-like cells. We were able to show an increasing differentiation with a decrease in proliferation and the stability of this differentiation behaviour over cell passages in this model, but we were not able to reduce the overall variability.

Adult↗
PubMed1998

The human analog of murine cystein rich protein 61 [correction of 16] is a 1alpha,25-dihydroxyvitamin D3 responsive immediate early gene in human fetal osteoblasts: regulation by cytokines, growth factors, and serum.

1Alpha,25-dihydroxyvitamin D3 (1,25-(OH)2D3) is a potent mediator of differentiation and maintenance of specific functions of osteoblasts. To detect novel targets for 1,25-(OH)2D3 action, we applied differential display PCR to human fetal osteoblast-like cells and identified the human analog of murine cystein rich protein 61 (hCYR61) as a 1,25-(OH)2D3-responsive immediate early gene in differentiated fetal osteoblast-like cells. The murine gene CYR61 is important for cell-cell and cell-matrix interactions, and it belongs to an emerging gene family of cysteine-rich proteins. hCYR61 messenger RNA (mRNA) steady-state levels were stimulated 11-fold by 10 nM 1,25-(OH)2D3 by 1 h and declined to control levels by 4 h. This transient stimulation of hCYR61 mRNA was not inhibited by cycloheximide but was prevented by actinomycin D, indicating that the 1,25-(OH)2D3 effect involves transcriptional events and does not require de novo protein synthesis. hCYR61 mRNA stability was not influenced by 1,25(OH)2D3, whereas cycloheximide treatment stabilized hCYR61 mRNA. FCS, as well as growth factors and cytokines such as basic fibroblast growth factor, epidermal growth factor, tumor necrosis factor alpha, and interleukin-1, strongly elevated hCYR61 mRNA steady-state levels within 1 h. hCYR61 mRNA was expressed also in primary human osteoblasts and osteosarcoma cell lines. Using a commercial tissue blot, hCYR61 mRNA was only observed in skeletal muscle. The fast and transient response of hCYR 61 to 1,25-(OH)2D3, serum, growth factors, and cytokines suggests an important role of hCYR61 for osteoblast function and differentiation.

Animals↗