Biomedical subjects

R Knüchel-Clarke

Publications and source records attributed to R Knüchel-Clarke.

4 recordsLinked to original sources

PubMed2005

[Urinary bladder tumours. The new 2004 WHO classification].

Increasing knowledge in molecular genetic research on urinary bladder carcinoma has allowed us to classify the morphological picture on the basis of a better understanding. But this new knowledge will only be ground-breaking if it can be correlated with the clinical outcome of urinary bladder tumours and with histopathological findings. The use of the new 2004 WHO classification results in a standardized diagnosis of urothelial tumours by means of an exact definition of the subgroups. In the future, trials can thus be compared worldwide and risk profiles can be stratified. Further research in molecular genetics and correlation with the current classification together with molecular biological techniques may allow refinement of this scheme, e.g. by immunohistochemical subclassifications, enabling identification of potentially genetically unstable tumours. In this paper we present the new 2004 WHO classification of urinary bladder tumours emphasizing the changes in relation to the former classifications focusing on histological typing, grading and molecular characterization. Until the new classification is finally validated, and those working in the field have become familiar with it, the WHO classification of 1973 should be mentioned additionally in the histopathological report.

Humans↗

PubMed1998

Detection of dysplastic lesions by fluorescence in a model of colitis in rats after previous photosensitization with 5-aminolaevulinic acid.

BACKGROUND AND STUDY AIMS: Endoscopic diagnosis of dysplastic lesions and early cancers in chronic ulcerative colitis is a major problem. Identification of suspicious lesions is influenced by the macroscopic appearance of the colon, but also by the endoscopist's experience. In this study we evaluated the identification of dysplastic lesions by the naked eye in an animal model of colitis after 5-aminoaevulinic acid-induced photosensitization. METHODS: 80 male Wistar rats were examined. Acute and chronic colitis were induced by oral application of 5% dextrane sulfate sodium (DSS) in 1-7 cycles (1 cycle = seven days DSS and 10 days water). For sensitisation 5-aminolaevulinic acid (5-ALA) at different doses (0, 10, 25, 50, 75, 100, and 200 mg/kg) was used. The colonic fluorescence was examined under a blue light (390-436 nm) for excitation. Histological findings of fluorescent and non-fluorescent biopsy specimens were recorded. RESULTS: Using 100 mg/kg 5-ALA intravenously for photosensitization, all dysplastic lesions (5/5) showed fluorescence (sensitivity 100%). However, at this concentration of 5-ALA, 60 false positive lesions were found out of 76 specimens taken from lesions that were not dysplastic--only 16 specimens of non-dysplastic lesions did not fluoresce (specificity 21%). Using 75 and 50 mg/kg 5-ALA intravenously sensitivity decreased to 92% (36/39) and 42% (5/12), respectively, while specificity increased to 35% (29/82) and 62% (45/73). Using 50 mg/kg 5-ALA intravenously, fluorescence-positive biopsy specimens showed inflammation of the colon in 31% whereas only 12% contained normal mucosa (p < 0.01). The distribution of fluorescence-positive biopsy specimens with histologically confirmed inflammation was similar for different grades of inflammation after sensitisation with 75 and 100 mg/kg 5-ALA, whereas with 50 mg/kg 5-ALA fluorescence-positive biopsy specimens contained significantly (p < 0.05) more moderate, massive, or ulcerative inflammation (79%) than mild inflammation (21%). CONCLUSION: 5-ALA induced photosensitization gave a high sensitivity, but low specificity in identifying dysplastic lesions in DSS-induced colitis in rats. In this animal model inflammation is a major factor in disturbing the fluorescence localisation of dysplasia after sensitisation with 5-ALA.

Acute Disease↗

PubMed1994

[Irradiation of wound blood from tumor surgery for retransfusion].

Intraoperative autotransfusion is contraindicated in tumor surgery because of the danger of tumor cell dissemination. We have tested the elimination of tumor cells in blood by irradiation for safe retransfusion. Tumor cells of various origin were mixed to washed red blood cells from volunteer blood donations. The blood was irradiated with 50 Gy. After isolation of the tumor cells by density gradient centrifugation they were tested for colony formation. While with different tumor cell lines (n = 12) 10 cells were sufficient to yield several colonies, as many as 10(10) cells did not result in any colony after irradiation of the blood. Similar results were obtained with cells cultured from blood salvaged during tumor surgery (n = 3), and with tumor cells prepared from various carcinomas (n = 10). Flow cytometric DNA analysis showed the irradiated cells in mitotic arrest. None of these cells had residual DNA metabolism expressed as incorporation of BrdUrd. We were able to demonstrate a rate of reduction in dividing cells of up to 10(9). With the typical irradiation sensitivity of tumor cells, with D0 values between 1 and 2 Gy, a dose of 50 Gy results in an effective log 12 reduction, sufficient for safe elimination of tumor cells found in shed blood. No adverse effects of the gamma-irradiation on the blood cells are to be expected, especially since the blood is retransfused without storage.

Blood↗

PubMedDate not supplied

[Tufted angioma].

We present a 2-year-old boy with a red, cutaneous-subcutaneous, nodule on the right elbow and a 2.5 year-old girl with an red-brown, indurated plaque on the left knee. Colour-coded doppler sonography of the boy's lesion showed vascular structures. A biopsy established the diagnosis of tufted angioma in both patients. Tufted angioma is clinically characterized by slowly spreading erythematous macules and plaques preferentially located on the upper trunk and neck in children. It is a benign tumor, malignant transformation has not been reported. The case history, clinical and histological findings contribute to the diagnosis. Tufted angioma has to be distinguished from Kaposi's sarcoma, angiosarcoma, hemangioma of infancy, sometimes bacillary angiomatosis and other cutaneous capillary malformations. Treatment of tufted angioma is difficult, various modalities like glucocorticosteroids, Interferon-alpha, flashlamp-pumped pulsed dye laser, excision and spontaneous regression have been described with varying results.

Biopsy↗