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F Bidlingmaier

Publications and source records attributed to F Bidlingmaier.

At least 37 records · Page 2Linked to original sources
PubMed1999

Sex- and age-specific differences in human brain CYP11A1 mRNA expression.

While the presence of CYP11A1 (P450SCC, cholesterol side-chain cleavage enzyme) has been well established in the brain of rodents, limited information is available on CYP11A1 expression in human brain. In both species, little is known regarding postnatal changes or sex specific differences in cerebral CYP11A1 expression. In the present study, we used a sensitive competitive reverse transcriptase polymerase chain reaction (RT-PCR) assay to quantify the amount of CYP11A1 mRNA in a large number of human brain tissue specimens obtained at neurosurgery. CYP11A1 mRNA is expressed approximately 200 times lower in the temporal lobe, frontal lobe and hippocampus than in adrenal tissue, known for high CYP11A1 mRNA expression. During childhood CYP11A1 mRNA concentrations in the temporal lobe increase markedly and reach adult levels at puberty. CYP11A1 mRNA is significantly higher in the temporal and frontal lobe cortex of women than in that of men. Our data demonstrate for the first time an age and sex dependent expression of CYP11A1 mRNA in the human brain.

Adrenal Glands↗
PubMed1999

Characterization of aromatase cytochrome P450 activity in the human temporal lobe.

Local aromatase-mediated conversion of androgens plays an important role in androgen action on the brain. To characterize estrogen formation in the human brain, we measured the microsomal aromatase activity of temporal lobe biopsies and compared it to that of human placenta using a highly sensitive 3H2O assay with [1beta-3H]androstenedione as substrate. Brain tissue was removed neurosurgically from 23 patients with epilepsy. Data of kinetic studies were analyzed with a computer-assisted, nonlinear, curve-fitting method using the Michaelis-Menten plus a nonspecific metabolism model. In contrast to data for placental aromatase activity, that for brain always had to be corrected for nonspecific tritium release. The mean K, values were 22.2 nmol/L in brain and 49.6 nmol/L in placenta. Inhibition experiments with atamestane, an inhibitor of aromatase cytochrome P450, revealed specific, dose-responsive, and competitive inhibition of both brain and placental aromatase activities. Placental aromatase activity was completely suppressible by atamestane, whereas in brain tissue there remained a residue of nonspecific tritium release. Subsequent experiments with cerebral cortex and subcortical white matter specimens of children and adults revealed a significantly higher aromatase activity in cerebral cortex than in subcortical white matter, but no sex or age differences were found.

Adolescent↗
PubMed1998

Expression of CYP19 (aromatase) mRNA in the human temporal lobe.

The conversion of androgens to estrogens by CYP19 (cytochrome P450AROM, aromatase) is an important step in the mechanism of androgen action in the brain. CYP19 expression has been demonstrated in various animal species, but studies in human postnatal brain tissue are lacking. Therefore, we investigated CYP19 mRNA expression in human temporal lobe tissues. We studied biopsy materials removed at neurosurgery from 34 women, 32 men and 10 children with temporal lobe epilepsy. Quantification of CYP19 mRNA was achieved by nested competitive reverse transcription-PCR. CYP19 mRNA concentrations did not differ significantly between women (2.6 +/- 0.6 arbitrary units, aU; mean +/- SEM) and men (1.6 +/- 0.3 aU) nor between cerebral cortex tissue (2.0 +/- 0.4 aU) and subcortical white matter tissue of adults (2.4 +/- 0.7 aU), but they were significantly lower in cerebral cortex specimens of children (0.9 +/- 0.6 aU) than in those of adults (p < 0.02). In conclusion, CYP19 mRNA is expressed in the temporal lobe of children and adults. CYP19 mRNA concentrations are significantly lower in specimens of children than in those of adults.

Adult↗
PubMed1998

Structural organisation of the gene encoding the alpha-subunit of the human amiloride-sensitive epithelial sodium channel.

The human amiloride-sensitive epithelial sodium channel (ENaC) is a member of the degenerin/ENaC family of ion channels and regulates fluid and electrolyte absorption across a number of epithelia, including kidney, colon and lung. Native ENaC has been shown to be a multimer made up of at least three homologous subunits (alpha, beta, gamma) and mutations affecting the channel complex have been identified in various human diseases. "Gain of function" mutations in one of the three ENaC subunits have been found to cause pseudoaldosteronism (Liddle's syndrome) and ENaC "reduction of function" mutations are found in patients affected with the recessive form of pseudohypoaldosteronism (PHA) type 1. In this report, we describe the genomic organisation of the human alphaENaC gene. Human alphaENaC consists of 13 exons spanning 17 kb on chromosome 12p13 and contains at least eight Alu sequences. In addition to the intron/exon boundaries, we have deciphered almost all the intron sequences and 475 bp of the CCAAT-less and TATA-less 5' flanking region.

Base Sequence↗
PubMed1998

Development of a highly sensitive nonisotopic immunoassay for the determination of salivary 17-hydroxyprogesterone: reference ranges throughout childhood and adolescence.

A sensitive nonisotopic immunoassay for the determination of 17-hydroxyprogesterone (17-OHP) levels in saliva was developed. The new time-resolved fluorometric immunoassay employs a specific polyclonal anti-17-OHP antiserum immobilized onto microtiter plates, a 17-OHP-biotin conjugate as a tracer, and streptavidin-europium a as secondary probe. The lower detection limit of the assay is 23.6 pmol/L (mean -3 s of a 22-fold zero determination) corresponding to 0.39 pg/well. The coefficients of intraassay variation are 8.8, 5.3, and 8.3% at the respective concentrations of 90.9, 454.5, and 1363.5 pmol/L. The coefficients of interassay variation are 8.8, 5.3, and 8.3% at the respective concentrations. Saliva was collected in commercially available devices. Reference ranges were established using 394 saliva samples from 132 healthy children, adolescents, and adults. Morning, midday, and evening levels of 17-OHP levels in saliva varied significantly in all age groups with morning levels being higher than midday and evening levels. Saliva samples (n = 57) were also obtained from 18 children with congenital adrenal hyperplasia (CAH). Salivary 17-OHP levels in the limited number of CAH patients studied ranged from 121 to 106,050 pmol/L. In conclusion 1) a new, sensitive nonisotopic immunoassay for measurement of 17-OHP in saliva has been developed; 2) reference ranges for healthy children, adolescents, and adults have been established; 3) there is a circadian pattern of 17-OHP levels in saliva at all ages; and 4) measurement of 17-OHP in saliva should be further evaluated over a longer period of time as a potentially reliable and powerful technique to monitor metabolic control in patients with CAH. As 17-OHP levels in saliva are stable for > 10 wk at 4 degrees C, the technique is ideally suited for outpatient sampling.

17-alpha-Hydroxyprogesterone↗
PubMed1998

Mineralocorticoid receptor splice variants in different human tissues.

The mineralocorticoid receptor (MR), a member of the steroid receptor family, acts as a transcription factor and mediates both aldosterone and cortisol effects. Aldosterone specificity in some tissues results from the inactivation of competing cortisol into cortisone by 11beta-hydroxysteroid dehydrogenase. In other tissues MR and the glucocorticoid receptor show overlapping physiological effects or may act together by forming a heterodimer. An additional MR splice variant (MR+4) has been found in different mRNA samples from rat tissues and human white blood cells, thereby implying additional modes of MR-regulated effects. We therefore looked for the presence of these two MR-mRNA isoforms in human classical aldosterone target tissues and various other tissues. MR-mRNA was found in all samples investigated, thereby showing the expression of MR to be more abundant than has been observed thus far. In addition, the MR+4-mRNA variant was also found in all the tissues examined.

Alternative Splicing↗
PubMed1998

Gestodene and desogestrel do not have a different influence on concentration profiles of ethinylestradiol in women taking oral contraceptives--results of isotope dilution mass spectrometry measurements.

OBJECTIVES: A new method for the quantitative determination of 17alpha-ethinylestradiol-17beta (EE2) in serum is presented here based on the principle of isotope dilution mass spectrometry (IDMS) with [13C]EE2 as internal standard. The technique was used to determine the concentration profiles of EE2 in the serum of female subjects who had taken oral contraceptives with different progestin components. The method has proved to be very reliable with respect to trueness, specificity, precision and detection sensitivity and offers considerable advantages compared with the immunological methods of measurement used to date. STUDY DESIGN: Forty-seven female volunteers took two different oral contraceptives containing EE2 combined with different progestins in accordance with a cross-over design. After the administration of 30 microg EE2 combined with 75 microg gestodene (EE2/GSD) or 150 microg desogestrel (EE2/DES), blood samples were taken from the subjects on certain days and in certain previously specified cycles in the course of 12 h after medication. RESULTS AND CONCLUSIONS: The biometric analysis of the results showed that the concentration profiles of EE2 were in their statistics, significantly equivalent after the administration of either of the two oral contraceptives. The sometimes contradictory results found in former studies after the administration of the different contraceptives were presumably due to the methodological shortcomings of the radioimmunological measurement technique. With the use of the highly accurate and specific technique of IDMS it can now be unequivocally established that the different progestins in the tested oral contraceptives have no influence on the bioavailability of EE2 (area under EE2 serum concentration curves, as usually defined in pharmacokinetics).

Administration, Oral↗
PubMed1997

An optimized protocol for mRNA quantification using nested competitive RT-PCR.

Nested competitive reverse transcription polymerase chain reaction is an effective tool for the quantification of low level expressed mRNAs. Competitive RNA standards with small deletions allow the use cRT-PCR. The sensitivity is further increased by the utilization of nested PCR protocols. To optimize quantification of low abundance mRNAs we modified established protocols for use of automated labstations and semiautomated sequencers. In placental tissue, known for a very high CYP19 (P450AROM, aromatase) expression, cRT-PCR and nested cRT-PCR yielded virtually identical results which could be confirmed by Northern blotting. CYP19 mRNA in breast tumour tissue ranged below detection levels for Northern blotting; however, using our modified assay CYP19 showed 1.5 to 15 fold higher expression levels than in normal glandular breast tissue. Our approach proved to be useful for the quantification of a gene with low level expression. The employment of labstations and semiautomated sequencers allows rapid analysis of large sample numbers.

Aromatase↗
PubMed1997

A comparison of different methods for diagnosing acromegaly.

OBJECTIVE: The present study was designed to assess the diagnostic value of different single measurements in comparison to the classic time-consuming method, the oral glucose tolerance test (OGTT), in acromegaly. DESIGN, PATIENTS AND MEASUREMENTS: IGF-I, free IGF-I, 24-hour-urinary GH (uGH), serum IGFBP-3 and 24-hour-urinary IGFBP-3 (uIGFBP-3) were measured in 12 patients with untreated active acromegaly, in 29 patients who had been treated but were not cured, in 13 patients with cured acromegaly and in 14 healthy control subjects, and compared with the results of the OGTT. RESULTS: In all patients with active acromegaly, whether they had been treated or not, nadir GH in OGTT was > 3 mU/l, whereas nadir GH was < 1.8 mU/l in the cured patients and the control subjects. In patients with untreated active acromegaly IGF-I, free IGF-I, uGH and IGFBP-3, but not uIGFBP-3, were significantly higher than in healthy individuals (P < 0.0001). Only IGF-I values did not overlap with the control group. In those patients with acromegaly who had been treated but not cured these parameters overlapped with the control group. In patients with acromegaly there was a significant correlation between nadir GH levels in OGTT and IGF-I (r = 0.71), free IGF-I (r = 0.76), IGFBP-3 (t = 0.73) and uGH (r = 0.81) (P < 0.0001), but no correlation with uIGFBP-3. CONCLUSIONS: Only be means of the OGTT could patients with active acromegaly be completely distinguished from the control subjects and from cured patients. IGF-I, free IGF-I, IGFBP-3 and uGH were useful in the diagnosis of acromegaly, but of limited value in the follow-up of acromegalic patients after treatment. The determination of free IGF-I, which has yet not been investigated in acromegaly, offered no advantage over that of total IGF-I and IGFBP-3; uIGFBP-3 was not useful in the diagnosis of acromegaly.

Acromegaly↗
PubMed1997

[Changes in the cytokine concentration (Il-6, Il-8, Il-1ra) and their cellular expression of membrane molecules (CD25, CD30, HLA-DR) after surgical trauma].

UNLABELLED: Elective surgical approaches and trauma cause changes in the production of different cytokines, an increased production of acute phase protein and changes in the expression of different cell surface markers. METHODS: In a prospective study we examined the C-reactive protein level, the production of the cytokines IL-6, IL-8 and IL-1 RA in 25 laparoscopic and 21 conventional cholecystectomies. In addition the cell surface markers CD25 and CD30 on different cell populations and HLA-DR on monocytes were measured. Statistical analysis was made by Student's-t-test and Mann-Whitney's rank sum test. RESULTS: The humoral markers showed a more distinct increase in patients operated on conventionally two and 24 hours after surgery, the differences between the two surgical approaches were significant (p < 0.01). The cell surface markers CD25 and CD30 showed the same reaction. The HLA-DR expression on monocytes was significantly lower in patients operated on conventionally. CONCLUSIONS: Elective surgical approaches cause changes in the immune system, which can be evaluated by the reaction of cytokines and cell surface markers. Laparoscopic cholecystectomies cause less activation of the immune system than conventional operations.

Acute-Phase Reaction↗
PubMed1996

Surgical stress induces a shift in the type-1/type-2 T-helper cell balance, suggesting down-regulation of cell-mediated and up-regulation of antibody-mediated immunity commensurate to the trauma.

BACKGROUND: Measuring serum cytokines, pituitary hormones, or acute phase proteins during or after surgery is not an optimal method for quantifying the impact of surgical procedures. In an effort to assess surgical stress by means of the immune response, we focused on changes in cell-mediated and antibody-mediated immunity as illustrated by the type 1/type 2 T-helper (Th1/Th2) cell balance. The sensitivity of this approach was evaluated by comparing laparoscopic and conventional cholecystectomy (LCE, CCE). METHODS: In a pragmatic prospective study 43 patients with symptomatic cholelithiasis were operated on either by LCE (n = 25) or CCe (n = 18). Blood sampling was done 24 hours before surgery, immediately before incision, and 2, 24, and 48 hours after surgery. Cell surface markers and cytokine production were used to characterize the Th1/Th2 balance and were measured by means of flow cytometry and enzyme-linked immunosorbent assay techniques. RESULTS: Activation of Th2 cells evokes the production and secretion of interleukin-4 (IL-4), which up-regulates the expression of immunoglobulin E receptors (Fo epsilon RII, CD23) on B cells. Phytohemagglutinin-induced IL-4 production in freshly isolated peripheral blood mononuclear cells from patients increased more after CCE than LCE (IL-4, +41% versus +17%; p < 0.05). Also the expression of CD23 on B cells was higher after CCE than LCE (+146% versus +63%; P < 0.01). CD30, a membrane molecule that belongs to the tumor necrosis factor receptor superfamily and probably is an important indicator of Th2 activity, was more evaluated on T cells from patients who underwent CCE. The Th1 response, characterized by phytohemagglutinin-induced IFN-gamma secretion in peripheral blood mononuclear cells and up-regulation of human leukocyte antigen-DR expression on monocytes, was lower after CCE than after LCE. CONCLUSIONS: This study shows that surgical stress induces a shift in the Th1/Th2 balance toward Th2, suggesting that cell-mediated immunity is down-regulated and antibody-mediated immunity is up-regulated after surgery. The evaluation of this shift may be clinically meaningful and help quantify even less invasive surgical procedures. When comparing CCE and LCE in this not strictly randomized study, we found LCE to be the less stressful procedure.

Down-Regulation↗
PubMed1995

Effects of the gonadotropin-releasing-hormone agonist, D-Trp-6-GnRH, on prolactin secretion in healthy young men.

The objective of this study was to examine the changes in basal plasma gonadotropin, alpha-subunit, sex steroids, and prolactin levels and the prolactin and luteinizing hormone (LH) secretion pattern before, during and 161 days after treatment with a depot preparation of D-Trp-6-GnRH in young men. Gonadotropins, alpha-subunit, sex steroids, and prolactin were measured in pooled plasma samples. Additionally, before treatment, several times during its course and on day 161 after treatment, blood samples were drawn for 8 h every 15 min for prolactin and LH measurements. After initial stimulation of the pituitary, administration of a depot preparation of D-Trp-6-GnRH resulted in a constant decrease in gonadotropin and sex steroid concentrations with LH and testosterone concentrations remaining within the limits of prepubertal levels from days 16 to 48. Alpha-Subunit concentrations (0.4 +/- 0.09 IU/l; mean +/- SE) increased after application of D-Trp-6-GnRH, and remained elevated until day 48. Basal prolactin levels (3.5 +/- 0.25 microgram/l) did not change significantly during treatment but afterwards increased consistently with maximal levels at day 141 (15.3 +/- 3.8 microgram/l); they had decreased at day 161 to 10.3 +/- 1.8 microgram/l which is significantly higher than before treatment (p < 0.05). On day 161, prolactin pulse amplitude was significantly higher than before and during treatment (p<0.05), while no significant changes in pulse frequency occurred. No significant temporal coupling between LH and prolactin release could be detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Immunoreactive inhibin concentrations in human gonads and adrenals during the first years of life.

We determined immunoreactive inhibin (irINH) concentration in the gonads and adrenals of healthy children (0-75 months) who had died suddenly. Testicular irINH peaked in the first 3 months of life with a significant drop in the 4th month (p < 0.05). In ovarian tissue, irINH was significantly lower than in the testes (p < 0.001) with highest levels during the first 4 months of life parallel to the highest estradiol concentrations. A significant correlation between gonadal testosterone/estradiol and irINH was observed. In adrenal tissue, irINH levels were significantly lower than in the gonads without sex-specific differences.

Adrenal Glands↗
PubMed1994

Secretion pattern of immunoreactive inhibin in men.

Chronological changes in serum concentrations of inhibin, a gonadal glycoprotein hormone, were studied in healthy male volunteers (age 24-27 years). Secretion profiles of immunoreactive inhibin (ir-inhibin) were compared with those of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone. Blood samples were collected every 15 min for 24 h. Serum inhibin concentrations were measured by a two-site immunoenzymatic assay with antibodies raised against distinct epitopes of the recombinant 1-32 amino acids of the alpha-subunit of human inhibin. The normal range for men was 0.79-3.1 U/l x 10(-3), the sensitivity of the assay was 0.1 U/l x 10(-3) (cv: within-assay, 6.8%; between-assay, 8.2%). Luteinizing hormone and FSH were measured by immunoradiometric assay and testosterone by radioimmunoassay. Secretion profiles of inhibin and testosterone were tested for diurnal variations by cosinor rhythmometry. Highest ir-inhibin concentrations were observed in the morning at 08.00 h, with peak values of 2.45-3.20 U/l x 10(-3). During the evening and the night, ir-inhibin levels were relatively low; lowest concentrations were observed between 01.00 h and 02.00 h at night: 1.20-1.86 U/l x 10(-3). Highest testosterone levels were observed in the morning (20.5-36.6 pmol/l), lowest concentrations were detected at night (7.35-12.6 pmol/l). Cosinor rhythmometry supported the suggestion that there is a clear circadian secretion of ir-inhibin and testosterone, respectively. The secretion pattern of ir-inhibin was analyzed by the Cluster pulse analysis computed algorithm, which identified four to seven inhibin pulses per day, depending on the person under observation.2+ volunteers follow a clear diurnal rhythm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Identification and DNA sequence analysis of 15 new alpha 1-antitrypsin variants, including two PI*Q0 alleles and one deficient PI*M allele.

We have investigated the molecular basis of 15 new alpha 1-antitrypsin (alpha 1AT) variants. Phenotyping by isoelectric focusing (IEF) was used as a screening method to detect alpha 1AT variants at the protein level. Genotyping was then performed by sequence analysis of all coding exons, exon-intron junctions, and the hepatocyte-specific promoter region including exon Ic. Three of these rare variants are alleles of clinical relevance, associated with undetectable or very low serum levels of alpha 1AT:the PI*Q0saarbruecken allele generated by a 1-bp C-nucleotide insertion within a stretch of seven cytosines spanning residues 360-362, resulting in a 3' frameshift and the acquisition of a stop codon at residue 376; a point mutation in the PI*Q0lisbon allele, resulting in a single amino acid substitution Thr68(ACC)-->Ile(ATC); and an in-frame trinucleotide deletion delta Phe51 (TTC) in the highly deficient PI*Mpalermo allele. The remaining 12 alleles are associated with normal alpha 1AT serum levels and are characterized by point mutations causing single amino acid substitutions in all but one case. This exception is a silent mutation, which does not affect the amino acid sequence. The limitation of IEF compared with DNA sequence analysis, for identification of new variants, their generation by mutagenesis, and the clinical relevance of the three deficiency alleles are discussed.

Alleles↗
PubMed1993

Protein kinase C regulates IL-8 and fMLP induced cytoplasmic Ca2+ increase in human granulocytes by receptor modulation measurements by flow cytometry.

Changes in cytosolic free Ca2+ influence important granulocyte functions like chemotactic behavior, adherence to endothelia, and phagocytosis. In the following study we used a simple reproducible procedure involving flow cytometry in combination with the fluorescent dye Fluo-3 to measure Ca2+ changes in human granulocytes. The aim of our study was to investigate the involvement of protein kinase C in regulating cytosolic free Ca2+ concentrations after stimulation of cells with IL-8 and fMLP. Both reagents induced a 5-6 fold increase in cytosolic Ca2+. Experiments conducted in Ca(2+)-free media showed a minor 18-29% decrease in cytosolic Ca2+ response, suggesting that intracellular Ca(2+)-stores are the main source for Ca2+ release after fMLP or IL-8 stimulation. Activators of protein kinase C, phorbol myristate acetate (PMA) and 1-oleyl-2-acetyl-sn-glycerol (OAG), inhibited cytosolic Ca(2+)-increase completely when induced by IL-8 and by 68-82% in the case of fMLP. Staurosporine, an inhibitor of protein kinase C, was able to attenuate or even abolish the PMA/OAG-effect. Our results show that changes in cytosolic Ca2+ due to IL-8 and fMLP signalling can be regulated by protein kinase C in human granulocytes. This regulatory role of protein kinase C involves some form of receptor modulation (i.e. phosphorylation, internalization, shedding).

Alkaloids↗