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G Oettling

Publications and source records attributed to G Oettling.

17 recordsLinked to original sources
PubMed2000

[Influence of histopathological factors on dynamic MR mammography].

AIM: To assess the histopathological background of enhancement mechanisms in dynamic MR mammography studies. METHODS: The dynamic MR mammography (MRM) examinations were done with a 1.5 T MR imager (Magnetom Vision, Siemens) using a double breast coil and a coronal FLASH-3D sequence. Enhancement data were acquired during 9 minutes post contrast medium injection (Gd-DTPA 0.2 mmol/kg). Acquisition time was 87 sec/slab. Early enhancement at the first post contrast measurement (E1) and slope of wash-out (SE2-L) were calculated. In immunohistology, proliferation was assessed by the monoclonal antibody Ki 67, capillaries were stained by a CD 31 antibody. Of a total of 48 operated patients, 58 lesions and 46 surrounding tissues were evaluated. RESULTS: Cellularity, capillary density and proliferation showed statistically significant correlations with E1 (p < 0.01). In multiple regression analysis, E1 was significantly associated only with high cellularity (p = 0.002) and the combination of high cellularity and high microvessel density (p = 0.002); a negative slope of wash out was significantly associated only with malignant histology (p = 0.027). CONCLUSIONS: Our findings indicate a direct influence of cellularity and microvessel density on early enhancement. The expression of the proliferation marker Ki 67 was not an independent predictor for contrast enhancement.

Adult↗
PubMed1998

Characterization of muscarinic receptors in the human melanoma cell line SK-Mel-28 via calcium mobilization.

In melanoma cells of primary and metastatic human melanomas muscarinic cholinergic receptors are present. Muscarinic receptors were shown to be expressed in morphogenetically active embryonic cells. Therefore, the possibility exists that in melanomas an embryonic trait is re-expressed after transformation. In the present study, we demonstrated the presence of muscarinic receptors in the human melanoma cell line SK-Mel-28 by immunofluorescence with the monoclonal antibody M 35 and characterized the receptors further by measuring calcium mobilization after muscarinic stimulation. Cell suspensions were stained with fura-2 and fluorescence was followed at 380 nm excitation in a fluorimeter cuvette. After the addition of acetylcholine or carbachol a steep decrease in fluorescence intensity indicated calcium mobilization from intracellular stores (peak reaction), which was followed by a constantly lowered fluorescence level indicating a steady influx of extracellular calcium in the presence of agonist. By quantitative evaluation, dose-response curves were obtained from which an ED of 4.3 x 10(-6) M was calculated for acetylcholine and an ED of 2.2 x 10(-5) M was calculated for carbachol. After preincubation with antagonists the dose-response curve of acetylcholine was shifted to the right. The inhibition constant of pirenzepine was calculated as 3.9 x 10(-7) M, of methoctramine as 6.8 x 10(-7) M and of 4-DAMP-mustard as 1.9 X 10(-8) M. Comparison with the data from the literature and those obtained in the chick embryo indicates that the muscarinic receptor in SK-Mel-28 melanoma cells pharmacologically behaves as the M3 type and corresponds to the embryonic muscarinic receptor characterized by us in earlier studies.

Atropine↗
PubMed1998

Mapping of androgen, estrogen and progesterone receptors in the anal continence organ.

OBJECTIVE: To investigate the expression of androgen, estrogen and progesterone receptors (ARs, ERs, PRs) in the tissues of the anal continence organ using immunohistochemical techniques. STUDY DESIGN: Thirty-nine samples of anorectal tissue were obtained from 23 patients (seven men, seven premenopausal women and nine postmenopausal women). Immunostaining for ARs, ERs and PRs was performed by the ABC technique using 3,3'-diaminobenzidine tetrahydrochloride as the chromogen. RESULTS: Specific immunostaining for ARs, ERs and PRs was found exclusively over cell nuclei. ARs were found in the smooth muscle cells of the internal anal sphincter in all but one of the females (10/11) and all males (7/7), ERs were found in 12/12 females and 4/7 males, and PRs were found in 4/10 females and 1/7 males. The squamous epithelium exhibited a similar pattern of immunostaining. The nuclei of the striated muscle fibers expressed none of the sex steroid receptors investigated. CONCLUSION: The intense expression of ARs, ERs and, in some cases, PRs in the tissues of the anal continence organ at all ages and in both sexes indicates that this organ is a target for sex steroid hormones.

Adult↗
PubMed1996

Immunohistochemical assessment of steroid hormone receptors in tissues of the anal canal. Implications for anal incontinence?

BACKGROUND: A prerequisite for a hormonal influence on anal continence in women is the presence of hormone receptors in the tissues of the anal canal. Using immunohistochemical techniques, we demonstrated and localized estrogen and progesterone receptors (ER, PR) in tissue sections of the anal canal. METHODS: Thirty-five specimens of the anorectal region from 21 patients (14 women, seven men) were examined histologically for smooth muscle (present in specimens from ten females and in seven males), striated muscle (present in three females and five males), and perimuscular connective tissue (present in 12 females and seven males). Immunostaining for ER and PR was then performed by incubating with primary anti-ER and anti-PR antibody and visualization of specific antibody binding by the ABC technique with DAB as chromogen. RESULTS: Positive staining for ER and PR was seen exclusively over cell nuclei. Estrogen receptors were found in the smooth muscle cells of the internal sphincter of all females (10/10) and in four of the seven males. Staining for ER was detected in the perimuscular connective tissue of all females (12/12) and in four of the seven males. No specific staining for ER or PR was found in the nuclei of striated muscle cells of the external sphincter in males or females (n = 8). In females, about 50% of the ER-positive tissues were also found to be positive for PR. Amongst the male patients, only one exhibited staining for PR, and this was confined to the smooth muscle. CONCLUSIONS: Expression of ER is a constitutional feature of the connective tissue and smooth muscle cells of the anal continence organ. Estrogen receptors and PR are not detectable in the striated muscle fibers of the external anal sphincter in either sex. The presence of ER in the stroma and smooth muscles of the anal canal suggests that these tissues are targets for estrogen. This constitutes a theoretical basis for the beneficial effects of estrogen and progestin replacement on anal continence in postmenopausal women.

Anal Canal↗
PubMed1993

[Laser therapy of the vulva, perineal area and uterine cervix].

Within a period of two years 205 patients of our colposcopy-laser-outpatient department have been treated with a 40 Watt CO2-laser. 97 patients had dysplastic or condylomatous lesions of the portio, 85 ones condylomas in the vulvar, vaginal or perianal regions. 70 per cent of laser vaporisations had been done ambulatoryly. Complication rate following laser conisation was 12 per cent, following laser vaporisation 0 per cent. The rate of recurrent or persistent dysplasias was 12 per cent, of condylomas 18 per cent on an average observation time of 16 months.

Cervix Uteri↗
PubMed1992

[Colposcopy, histology, cytology and HPV findings in patients with condylomata of the vulva].

The presence of vulvar condylomata acuminata shows evidence HPV infection of the vulva. 49 patients with such lesions came to our hospital for laser treatment. At that time, none of the patients were aware of their cervical disease. Colposcopy and biopsy of the cervix revealed in eight (16%) of the 49 patients CIN I and CIN II in one patient (2%). Condylomata or other HPV-associated lesions were found in seven patients (14%) and cervicitis in two (4%). HPV were detected in the cervix in 23 patients (46%). HPV types 16 and 18 were found in seven patients (14%) and HPV types 31, 33 and 35 in four patients (8%). It is concluded, that patients with condylomata acuminata of the vulva have a high risk of developing CIN and should undergo colposcopy.

Biopsy↗
PubMed1992

Characterization of the Ca2+ influx into embryonic cells after stimulation of the embryonic muscarinic receptor.

Embryonic cells transiently express an embryonic muscarinic system during morphogenesis. Stimulation of the embryonic muscarinic receptor results in biphasic intracellular Ca2+ mobilization: an initial "peak" due to Ca2+ release from intracellular stores is followed by a sustained "plateau" of enhanced cytoplasmic Ca2+ due to influx of extracellular Ca2+. In the present investigation, we characterized the Ca2+ influx by measuring the cytoplasmic free Ca2+ concentration [Ca2+]i using the Ca2+ indicator fura-2: 1. The increase of [Ca2+]i during the plateau depended linearly on the logarithm of the extracellular calcium concentration whereas the initial peak was almost independent from extracellular calcium. 2. The organic Ca2+ entry blockers verapamil, gallopamil, nifedipine, nitrendipine and the inorganic blockers Mn2+, Mg2+ and La3+ were without effect on both phases of Ca2+ mobilization. Only Ni2+ at concentrations above 1 mM was able to reduce the influx without affecting the intracellular Ca2+ release. 3. Substitution of extracellular Na+ by guanidine+, choline+ or tris+ and membrane depolarisation by increasing the extracellular K+ concentration had no effect on either phase of Ca2+ mobilization. We conclude that a non-voltage dependent, receptor-operated influx mechanism, probably a "second messenger operated Ca2+ channel", is responsible for the Ca2+ influx after stimulation of the embryonic muscarinic receptor.

Acetylcholine↗
PubMed1991

Effects of EPF treatment in human mononuclear cells.

Early Pregnancy Factor (EPF) is one of the earliest pregnancy associated signals, communicating the ensuing pregnancy to the maternal organism. Data published by others on the mouse suggest that EPF bound to spleen cells causes the release of two H2-restricted "suppressor factors" responsible for the rosette inhibiting activity of EPF in the rosette inhibition test. Using human material, we were able to detect the release of a second entity from mononuclear cells that is able to suppress rosette formation in the human rosette inhibition test. In an attempt to show an intracellular EPF effect in the target cell, cytosolic free calcium concentrations were measured in EPF-treated mononuclear cells from peripheral blood. Our findings did not, however, show any changes of intracellular free Ca(2+)-concentrations under the chosen conditions.

Calcium↗
PubMed1990

Vasoactive intestinal polypeptide (VIP) induces calcium mobilization in the human neuroblastoma cell line SK-N-SH.

Release of catecholamines, a Ca2(+)-dependent process, is the most useful biochemical marker in the diagnosis of neuroblastoma. Unfortunately, its stimulus is still unknown. We found that vasoactive intestinal polypeptide (VIP), in addition to acetylcholine and muscarine (but not nicotine), causes elevation of the cytoplasmic Ca2(+)-concentration in the highly differentiated human neuroblastoma cell line SK-N-SH, with or without the presence of extracellular Ca2+. Additionally, VIP was detected in SK-N-SH cells (0.65 ng/10(6) cells). Based on these observations and the fact that neuroblastoma is not innervated in vivo, we hypothesize that in this tumor VIP is responsible for Ca2(+)-dependent release of catecholamines in an autocrine or paracrine fashion.

Acetylcholine↗
PubMed1989

An embryonic Ca++ mobilizing muscarinic system in the chick embryo heart.

In the embryonic and in the adult heart muscarinic stimulation reduces the heart rate. Here we demonstrate that in the embryonic heart an additional muscarinic system is present, which is characterized by Ca++ mobilization and corresponds to the embryonic muscarinic system in other organ anlagen. In suspensions of embryonic chick heart cells we measured release of Ca++ from intracellular stores and influx of extracellular Ca++ with fura-2 and chlorotetracycline after muscarinic stimulation and determined the [3H]quinuclidinylbenzilate binding sites. We observed intense Ca++ mobilization at day 4, weaker reactions between day 4.5 and 11, and no Ca++ response at day 13. The pharmacological profile was identical to the profile of Ca++ mobilization in cells from other embryonic tissues in which the general embryonic muscarinic system is expressed. In parallel, we studied the effect of muscarinic agonists and antagonists on the heart rate of isolated embryonic hearts at day 4 and 5 in a perfusion chamber. Oxotremorine and bethanechol being antagonists or weak partial agonists in Ca++ mobilization, behaved as full agonists in frequency regulation. Thus, the pharmacological profile of the transient embryonic muscarinic system was different from that of the definitive adult form.

Animals↗
PubMed1988

Receptor analysis: an arithmetic correction improves precision and accuracy.

Data of receptor analysis by ligand binding experiments should be processed using the formula DCORR = (B1 - B2.F1/F2)/VS.DCORR is an estimate of the concentration of receptor-bound radioligand; B1 and F1 are estimates of bound and free radioligand in assay 1; B2 and F2 are the corresponding values obtained from the parallel assay 2, which contains an additional excess of nonlabeled ligand; VS is the volume of assays 1 and 2 that was submitted to separation. DCORR will be superior to the conventional formula, D = (B1 - B2)/VS, if the radiolabeled receptor-ligand complexes are incompletely separated from nonspecifically bound and free radioligands. DCORR corrects for the systematic underestimation of the specifically bound radioligand implicated in D as well as for random errors due to imprecise pipetting during preparation of the parallel assays. The superiority of DCORR over D is verified by processing the data of androgen receptor analyses using agar gel electrophoresis for separation of bound and free radioligand.

Animals↗
PubMed1988

Muscarinic receptor-mediated intracellular Ca2+ mobilization in embryonic chick heart cells.

Activation of muscarinic receptors of heart cells elevates the intracellular Ca2+ concentration. The increase is considered to be due to influx of extracellular Ca2+. We show that intracellular Ca2+ mobilization is involved. Cell suspensions prepared from hearts of 6-day-old chick embryos were loaded with the fluorescent Ca2+ chelator chlortetracycline. Muscarinic stimulation induces a dose-dependent fluorescence decrease (ED50 = 2.6 x 10(-6) M) indicating intracellular Ca2+ mobilization.

Acetylcholine↗
PubMed1988

Expression of the Ca2+ mobilizing muscarinic system in the chick embryo correlates with morphogenesis.

We describe muscarinic receptors and intracellular Ca2+ mobilization after cholinergic stimulation in cell suspensions prepared from chick embryos between day 2 (stage 12/13) and day 13 (stage 40) of development. Cell suspensions are prepared from whole chick embryos and from embryonic hearts, heads or brains, limb buds, and trunks. Muscarinic receptors are measured using [3H]quinuclidinylbenzilate as specific ligand. Intracellular Ca2+ mobilization is determined by changes of chlorotetracycline fluorescence. (1) Considerable amounts of muscarinic receptors are found in all parts of the embryo and at all stages tested. (2) The intracellular Ca2+ response after stimulation by muscarinic agonist shows a peak at day 3-4 (stage 23). (3) The pharmacological profile of the Ca2+ response remains constant during embryonic development and differs from the profiles of most adult systems. (4) The 'embryonic muscarinic system' is uniformly expressed in cells from neural and non-neural tissues. It appears and disappears independently of innervation.

Acetylcholine↗
PubMed1987

Chloroquine is a muscarinic antagonist. Binding and dose-response studies with chick embryo cells.

A muscarinic acetylcholine receptor is present on undifferentiated cells of the chick embryo. We show that, in the chick embryo, chloroquine binds to the muscarinic receptor site and behaves as a muscarinic antagonist. In competition studies performed with cell suspensions, chloroquine displaced the specific muscarinic ligand [3H]quinuclidinylbenzilate ([3H]QNB) from the receptor. The dissociation constant (KD) of chloroquine was calculated to be 6.0 X 10(-6) M. In saturation studies performed in chick embryo homogenate, chloroquine shifted the binding curve of [3H]QNB to the right (KD = 4.8 X 10(-6) M). Dose-response curves were established by measuring the acetylcholine-triggered Ca2+ mobilization in cell suspensions by means of a fluorometric assay with chlorotetracycline. Chloroquine shifted the dose-response curve to the right. The inhibitory constant (KI) of chloroquine calculated from the dose-response curve was 1.5 X 1 10(-5) M. Our observations provide an explanation for the known interference of chloroquine with the muscarinic cholinergic systems in a variety of adult organs.

Animals↗
PubMed1985

The muscarinic receptor of chick embryo cells: correlation between ligand binding and calcium mobilization.

In this report we characterize muscarinic cholinergic receptor on embryonic cells. We established dose-response curves by fluorometric measurement of Ca2+ mobilization in cell suspensions of whole chick embryos stage 23/24. Ca2+ mobilization was quantitated by standardization of chlorotetracycline (CTC) fluorescence changes after stimulation with muscarinic agonists. We determined ED50 values for the agonists acetylcholine and carbachol as 3.4 X 10(-6) and 2.7 X 10(-5) M, respectively. Pilocarpine and oxotremorine were found to act as reversible competitive antagonists with inhibition constants (Kl) of 5.0 X 10(-6) and 1.4 X 10(-6) M, respectively. Bethanechol, which induced only 23% of the maximal effect obtained by acetylcholine, was a partial agonist with an ED50 of 4.8 X 10(-4) M. Its antagonistic component is expressed by an inhibition constant of 1.9 X 10(-4) M. In parallel, binding studies were performed in a competition assay with [3H]-quinuclidinylbenzilate. For the agonists acetylcholine and carbachol, binding parameters were best fitted by a "two binding-sites model." Comparison with dose-response curves indicated that Ca2+ mobilization was triggered via the high-affinity binding site. The inhibition constants of antagonists derived from the shift of dose-response curves corresponded to the fitted KD values of the binding studies when a "one binding-site model" was applied. Combination of dose-response and binding data showed close proportionality between receptor occupancy and calcium mobilization. No spare receptors were present.

Acetylcholine↗
PubMed1983

A quantitative assay for the cytoplasmic androgen receptor using [3H]dihydrotestosterone in the presence of NAD+-nucleosidase.

In prostatic cytosol DHT1 is metabolized to 5 alpha-androstane-3 alpha (or beta), 17 alpha-diols with a half life of 2 h even at 4 degrees C. Thus, [3H]DHT appears to be a poor marker for a quantitative assessment of androgen receptors (AR). Methyltrienolone (R1881) seems to be advantageous as it is not metabolized. However, because of considerable binding to progestin receptors, assays using [3H]R1881 are not specific for AR in tissues containing progestin receptors. We, therefore, developed a specific assay for AR using [3H]DHT (14 nM) as marker, where metabolism of DHT is prevented by pre-incubation with NAD+-nucleosidase. The [3H]DHT-receptor complex is separated from free, SHBG-bound and unspecifically bound [3H]DHT by agar gel electrophoresis. The binding sites of high affinity and low capacity are characterized by suppression with unlabelled R1881 (2 microM) in a parallel assay. Under these conditions DHT and R1881 appear to have the same kinetics of association and dissociation. Weighted non-linear regression analysis of specific binding capacity at various ligand concentrations reveals that in rat prostatic cytosol the affinity of DHT (Kd = 0.405 +/- 0.0839 nM) is significantly higher (P less than 0.01) than that of R1881 (Kd = 1.25 +/- 0.271 nM).

Animals↗