Biomedical subjects

R A Böni

Publications and source records attributed to R A Böni.

7 recordsLinked to original sources

PubMed1997

D1 dopamine receptors are not expressed in human melanoma.

D1 dopamine receptor mRNA has been demonstrated in mouse melanoma cells, and the expression of these G-protein-coupled receptors in human melanoma was therefore presumed when dopamine receptor binding radiopharmaceuticals were found to be useful for the detection of metastases in whole-body scintigraphy. The aim of this study was thus to investigate if D1 dopamine receptor mRNA or protein could be directly demonstrated in melanoma cells. The presence of D1 dopamine receptor mRNA was investigated in six human melanoma cell lines from metastases using reverse transcriptase-polymerase chain reaction (RT-PCR). In addition, in vitro binding assays with the D1 dopamine receptor agonist 125I-Sch 23982 were performed in 19 melanoma metastases. No D1 dopamine receptor mRNA could be detected by RT-PCR. All melanotic metastases were found to accumulate 125I-Sch 23982, with the presence of binding sites and intensity of 125I-Sch 23982 labelling correlating to the amount of melanin present in the metastases. Two amelanotic melanomas did not accumulate 125I-Sch 23982. D1 dopamine receptors could not be detected by means of RT-PCR or in vitro binding assays in human melanomas. Detection of antagonists is best explained by non-specific binding to melanin.

Animals↗

PubMed1997

Laser ablation-induced changes in the prostate: findings at endorectal MR imaging with histologic correlation.

PURPOSE: To correlate laser ablation-induced changes in the prostate as depicted at endorectal magnetic resonance (MR) imaging with results at histologic examination. MATERIALS AND METHODS: In eight patients with prostate carcinoma, visually guided laser ablation was performed during lymphadenectomy. Radical prostate resection was performed 4-9 days (mean, 6.9 days) after ablation in seven patients and at 70 days in one patient. The study protocol consisted of (a) endorectal T2-weighted fast spin-echo imaging, (b) dynamic T1-weighted spoiled gradient-echo imaging prior to and after injection of contrast material, and (c) gadolinium-enhanced T1-weighted spin-echo imaging. Imaging findings were correlated with macroscopic and histologic findings. RESULTS: Histologic examination revealed periurethral necrosis with a marginal zone that consisted of partially necrotic tissue, dilated vessels, and hemorrhagic areas. Considerable interindividual difference was observed in the extent of morphologic alterations (area, 0-18.0 cm3). Gadolinium-enhanced images were best suited for assessment of laser ablation-induced changes. The correlation between the volume of altered tissue measured on MR images and in macroscopic specimens was excellent (r2 = .96). CONCLUSION: MR imaging helped monitor changes induced with laser ablation (which differed greatly among individuals). MR monitoring may thus be useful in patients with obstructive benign prostatic hyperplasia after laser ablation.

Aged↗

PubMed1996

[Preoperative T-staging of prostatic carcinoma: endorectal magnetic resonance tomography compared with other imaging and clinical methods].

PURPOSE: The diagnostic value of endorectal magnetic resonance imaging (MRI) in comparison to clinical information and other imaging modalities was analysed in order to define the most accurate preoperative staging method. METHODS: 54 patients with biopsy proven prostate carcinoma, who underwent subsequent prostatectomy, were examined with an endorectal surface coil. The results were compared to body coil MRI, digital rectal examination and prostate specific antigen levels. In 37 patients, results of endorectal ultrasound were available. RESULTS: Staging accuracy, sensitivity and specificity of endorectal coil MRI were 83.3%. For body coil MRI, staging accuracy was 59.2%, sensitivity 43.3% and specificity 82.6%, for transrectal ultrasound 59.5%, 36.4% and 91.7% and for the digital rectal examination 55.6%, 26.7% and 91.7%, respectively. Staging accuracy of endorectal MRI was significantly (p < 0.05) superior to that of the other imaging modalities. CONCLUSION: Endorectal coil MRI allows reliable distinction between localised and advanced tumour stages and is superior to other imaging techniques in this regard. It can thus be recommended for staging in patients with prostate carcinoma.

Biopsy↗

PubMed1996

Lack of expression of dopamine D2 receptors in malignant melanoma: evidence for interaction of iodobenzofurans with melanin.

OBJECTIVES: (1) To compare scintigraphy using the new dopamine D2 receptor binding radioligand iodobenzofuran (IBF) versus whole-body positron emission tomography (PET) in demonstrating metastasizing melanoma, and (2) to determine, for the first time using a panel of histochemical techniques, whether the ability of D2 receptor binding radioligands to detect melanoma metastases is due to tumor-expressed D2 receptors. METHODS: Seven patients with metastatic melanoma were examined using 123I-IBF scintigraphy. Findings were compared to the results of PET and metastasis histochemistry: D2 receptor mRNA assay (metastases: n = 5; melanoma cell lines: n = 4) using the reverse transcriptase polymerase chain reaction (RT-PCR) versus D2 receptor-transfected Chinese hamster ovary cell controls: in vitro 125I-IBF binding (n = 19), and immunohistochemical staining for dopamine D2 receptor protein (n = 19). RESULTS: IBF scintigraphy detected 2/10 melanoma metastases detected by PET (sensitivity 20%). No dopamine D2 receptor mRNA was found in melanoma cells using RT-PCR. The binding of 125I-IBF correlated with the amount of melanin present in the metastases; two amelanotic melanomas both failed to bind 125I-IBF. Immunohistochemical staining was negative in all metastases. CONCLUSION: Melanoma cells do not appear to express dopamine D2 receptors. Although IBF had high dopamine D2 receptor affinity, its ability to detect melanoma metastases is more likely explained by low affinity binding to melanin than by the presence of dopamine receptors.

Adult↗

PubMed1995

Staging of metastatic melanoma by whole-body positron emission tomography using 2-fluorine-18-fluoro-2-deoxy-D-glucose.

Metastatic melanoma was staged in 15 patients using whole-body positron emission tomography (PET) and the radiopharmaceutical 2-fluorine-18-fluoro-2-deoxy-D-glucose (FDG). PET correctly demonstrated 30 metastases in lung, brain, pancreas, nasal cavity, skin and subcutaneous tissue, and lymph nodes. It detected 97% of all metastases exceeding its spatial resolution (> 5 mm). Two cutaneous metastases (approximately 3 mm) did not show increased FDG uptake; the overall detection sensitivity was 91%. Two false-positive lesions in one patient were due to severe wound infection. PET correctly excluded malignancy in four cases where suspicious lesions were found with conventional cross-sectional imaging modalities but later ruled out by fine-needle biopsy. PET therefore proved to be an excellent method for staging of metastatic melanoma. Due to its high sensitivity for malignant lesions and the possibility of covering the whole body in one examination, it can replace staging techniques employing multiple imaging modalities: chest X-ray, ultrasonography and computed tomography. Furthermore, it provides information on the malignant potential of the detected lesion.

Adult↗

PubMed1995

[Staging in prostate carcinoma].

A correct staging of clinically localized prostate cancer should nowadays consist of: digital rectal examination (DRE) (+/- -transrectal ultrasound [TRUS]) bone scan abdominal computed tomography or body coil magnetic resonance imaging (+/- laparoscopic lymph node dissection according to the PSA level) endorectal surface coil MR imaging (if available) The above-mentioned methods are discussed with preference to the new technology of endorectal surface coil magnetic resonance imaging (E-MRI) of the prostate.

Aged↗

PubMedDate not supplied

Multiple necrotic uterine leiomyomas causing severe puerperal fever: ultrasound, CT, MR, and histological findings.

The case of a patient with severe fever in the puerperium is presented. Ultrasound, CT, and MRI revealed multiple myomas; all the myomas, even the smallest ones, were hypodense on pre- and postcontrast enhanced CT and presented with high signal intensities on T2-weighted MRI. After hysterectomy, histology demonstrated necrosis of all leiomyomas without hemorrhage or inflammatory reaction. Therefore, fever was caused solely by extensive necrotic degeneration of the fibroids, probably due to hypoperfusion related to delivery or hormonal changes during pregnancy and puerperium.

Adult↗