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Biomedical subjects

H F Karthaus

Publications and source records attributed to H F Karthaus.

30 records · Page 2Linked to original sources
PubMed1988

Carcinoma of the urinary bladder: MR imaging with a double surface coil.

Twenty-four patients with carcinoma of the urinary bladder were examined with MR imaging by using both a conventional body coil and a newly designed wraparound double surface coil. All patients had T1- and two patients had T2-weighted pulse sequences with both coils. Because of the long examination times, T2-weighted sequences in all other patients were obtained by using the double surface coil only. Nine patients underwent radical cystectomy, while the other patients had deep transurethral tumor resection and a clinical follow-up of at least 1.5 years. The results of imaging with the surface coil showed a twofold improvement of spatial resolution compared with the images obtained with the body coil. The RF field homogeneity was excellent, and the field of view was sufficiently large to achieve a complete study of the pelvis and the lower abdomen in one sequence. For the T1-weighted images, the higher spatial resolution of the double surface coil resulted in a significant (p less than .10) improvement in tumor staging. The accuracies of double-surface-coil and body-coil imaging were 79% and 54%, respectively. Double-surface-coil imaging appears to provide better MR images of the urinary bladder than body-coil imaging does, resulting in more accurate staging of tumors on T1-weighted pulse sequences.

Carcinoma, Transitional Cell↗
PubMed1987

Expression of proto-oncogenes in xenografts of human renal cell carcinomas.

In a recent paper, we described the expression pattern of proto-oncogenes in primary human renal cell carcinoma [12]. To test the possibility of using xenografts as a useful alternative for such studies, we analyzed xenografts of a number of human renal cell carcinomas in nu/nu mice. Xenografts included RC2, RC14, RC21, RC43 and NC65. Northern blot analysis indicated that c-Ras was expressed in all these xenografts. The identity of the ras transcripts in the individual xenografts was further specified as c-Ha-ras, c-Ki-ras or N-ras. Expression of c-myc and the p53 gene was also found in a number of these tumors. Only RC21 failed to express the c-myc or the p53 gene. In all xenografts, a 3.0 kb c-fes/fps mRNA was present. In RC2, RC14, RC21 and RC43, low levels of the 4.8 kb ab 1 transcript were detectable. Transcripts of myb and sis could not be detected in any of the xenografts. The results indicated that the expression pattern of a variety of proto-oncogenes in xenografts of human renal cell carcinomas was similar to that in the primary tumors.

Animals↗
PubMed1987

Metastatic cancer of the prostate managed with buserelin versus buserelin plus cyproterone acetate.

We recruited 71 previously untreated patients with metastatic prostatic carcinoma to 2 separate consecutive prospective phase 2 studies done by the same group of investigators according to the same protocols in which only the treatment regimens differed. Of the patients 58 were treated with the luteinizing hormone-releasing hormone analogue buserelin alone (0.4 mg. 3 times daily intranasally) and 13 were treated with buserelin combined with cyproterone acetate, a potent antiandrogen (50 mg. 3 times daily orally). The objective of the study was to investigate the efficacy, safety and tolerability of the medication used during at least 12 months by studying adequate endocrine parameters, the rate and duration of response, as well as the rate of progression and possible side effects. All endocrine parameters were studied in 1 laboratory. Modified response criteria of the National Prostatic Cancer Project were used. The endocrine studies showed an effective suppression of plasma testosterone to castration levels by buserelin after an initial increase during the first 2 weeks. Luteinizing hormone and follicle-stimulating hormones were lowered significantly and could not be re-stimulated by the intravenous application of luteinizing hormone-releasing hormone. There was no correlation of plasma testosterone with response and progression. However, a significant correlation existed between higher basal cortisol levels at entry, and after 3 and 6 months, and progression. Response is reported for all patients at the 12-month interval and did not seem to differ among treatment groups. The rate of progression after all patients had been treated for 1 year was 37.9 per cent in the buserelin group and 41 per cent in the buserelin plus cyproterone acetate group. Three early deaths occurred in the buserelin group. Except for impotence, only mild side effects were noted. Our study shows that treatment of metastatic prostatic cancer by means of the luteinizing-hormone-releasing hormone analogue buserelin is safe and effective. The results obtained are compatible with those obtained by castration. In our study a superiority of total androgen withdrawal over testicular suppression alone could not be shown.

Buserelin↗
PubMed1986

Tissue-specific markers in flow cytometry of urological cancers. II. Cytokeratin and vimentin in renal-cell tumors.

Nine primary human renal-cell tumors (RCT), one lymph-node metastasis, 4 human xenografts of a RCT in nude mice and a rat RCT line were analyzed by flow cytometry (FCM) using propidium iodide for DNA analysis and antibodies to cytokeratin and vimentin in the indirect immunofluorescence technique for labelling of specific tumor-cell populations. By means of 2-dimensional FCM analysis, vimentin- and cytokeratin-positive (tumor) cells were compared and their DNA content and proliferative fraction analyzed separately from those of cytokeratin-negative stromal and inflammatory cells. In primary human RCT, 2 subpopulations of cells were detected and analyzed separately. Small numbers of tumor cells with an abnormal DNA stemline were also detected. In addition, co-expression of intermediate filament proteins of both the cytokeratin and the vimentin types was detected in the aneuploid cell population. Comparison of 2 model systems of RCT with primary human RCT revealed a similar pattern of tumor-cell subfractions within these tumors. The 2-parameter FCM analysis permits the detection of subpopulations in complex cell suspensions and the quantification of these fractions, as well as analysis of their cellular DNA content.

Animals↗
PubMed1986

Expression of the human fes cellular oncogene in renal cell tumors.

Renal cell tumors were screened for expression of the cellular oncogenes c-abl, c-fes, c-fms, c-myc, c-ras, and c-sis in dot blot hybridization analysis. Expression of c-ras and c-myc was clearly detectable in most of the 15 tumors that were studied. The c-fes oncogene appeared to be expressed in only two of them. Comparative Southern blot analysis of molecularly cloned human c-fes DNA and genomic DNA of the 15 renal tumors revealed no major genetic differences. Northern blot analysis of poly(A)-selected RNA from the fes-positive tumors with the complete viral v-fes oncogene of the Gardner-Arnstein strain of feline sarcoma virus as a molecular probe revealed hybridization of RNA species of 3.0 and 4.5 kb, respectively. The 3.0 kb c-fes transcript has also been reported in RNA from patients suffering from acute myelogenous leukemia. The 4.5 kb transcript, however, has not been described before and represents either a c-fes-related splicing intermediate or, more likely, a completely processed transcript. The results of this study could imply that human c-fes coding sequences are more extensive than was previously assumed.

Carcinoma, Renal Cell↗
PubMed1982

An approach to undiversion in children.

This report reviews our experience in enabling 21 patients to dispense with their urinary drainage bags. Seventeen patients have undergone reconstruction of their urinary tracts; 14 of these patients are continent, one is wet at night and 2 are totally incontinent. Three patients have been converted to a ureterosigmoidostomy: 2 of these are dry and one is wet at night. One patient catheterises a continent stoma and is dry. The length of follow-up is short (average 1 1/2 years) but renal function and the upper tracts have remained stable.

Child↗
PubMedDate not supplied

Multiparameter analysis of four human renal cell carcinoma xenografts in nude mice.

Four human renal cell carcinoma xenografts (RC2, RC14, RC43, NC65), maintained in nude mice for several years, were investigated in a multi - disciplinary study, using (immuno) histochemical, biochemical and ultrastructural techniques. Histological, cellular, nuclear and biological characteristics were investigated. All tumors showed histologically recognizable features of human renal cell carcinomas, although marked differences between the four tumors were seen, both at the histological and ultrastructural level. Flowcytometric analysis of tumor cell suspensions allowed DNA quantification as well as the detection of subpopulations. Immunohistochemical staining procedures using tissue specific antibodies against intermediate filament proteins revealed two populations of tumor cells. Most tumor cells in three of the xenografts coexpressed cytokeratins and vimentin, while in RC43 most of the tumor cells expressed only vimentin. Northern blot analysis showed a higher expression of vimentin mRNA in all tumors as compared to normal kidney tissue. RC43 showed a three-fold higher level of vimentin mRNA than the other xenografts. Growth potential in the human tumor cloning system was evaluated by temporal growth pattern analysis. These experiments showed that the xenografts resemble human primary renal cell tumors in different ways, and reflect different characteristics that can be present in human renal cell carcinoma.

Aneuploidy↗
PubMedDate not supplied

Multidisciplinary evaluation of rat renal cell carcinoma.

The rat renal cell carcinoma system as described by deVere White and Olsson in 1980 is used widely as a model for its human counterpart. The tumor arose spontaneously in a male Wistar Lewis rat and its behaviour has been shown to be stable during multiple passages. We have compared this tumor with the human renal cell carcinoma using a multidisciplinary approach. Light microscopy and electron microscopy showed a great resemblance of this rat tumor to a human renal cell carcinoma of the clear cell type with the ultrastructural presence of desmosomes. With the use of tissue specific antibodies against intermediate filament proteins, it could be shown that their expression is comparable to human renal cell carcinoma, i.e. coexpression of vimentin and different cytokeratins in the tumor cells. The cells could also be shown to contain cytokeratin 18. An aneuploid cell population in the tumor, expressing both vimentin and keratin, could be characterized by DNA flow cytometry in double labeling experiments. Comparison of normal and malignant rat kidney tissue by Northern blot analysis revealed increased levels of vimentin mRNA. In conclusion, this tumor model seems to have several histological and biological properties in common with the human renal tumor.

Actins↗