Biomedical subjects

B T Hendriks

Publications and source records attributed to B T Hendriks.

10 recordsLinked to original sources

PubMed1995

Semi-automated database design by the end-user.

An information system was developed to manage the data for a large number of research projects simultaneously. The system, called URIS, has facilitated the management of research data in an academic urological department. It enables end-users, who are not necessarily skilled computer scientists, to design their own databases semi-automatically, by supporting data entry screen design and the specification of research items. The system creates the database tables automatically after these activities. The specification of research items is the most important but also most difficult part in this process.

Computer Literacy↗

PubMed1992

Inhibition of rat bladder tumor (RBT323) growth by tumor necrosis factor alpha and interferon-gamma in vivo.

The antiproliferative activities of recombinant rat gamma-interferon and recombinant human tumor necrosis factor alpha were evaluated in a new rat bladder tumor model, RBT323. The RBT323 is a spontaneously arisen, serially transplantable, bladder tumor in ACI rats. Histologically and ultrastructurally this tumor is a grade 2-3 transitional tumor without squamous cells. The RBT323 appears to be non-immunogenic in tumor excision and rechallenge experiments. The tumor was transplanted subcutaneously and the drugs were administered peritumorally. Gamma-interferon and tumor necrosis factor monotherapy starting two days after tumor implantation showed dose-dependent growth inhibiting effects in the dose range tested. Combination treatment with gamma-interferon and the highest dose of tumor necrosis factor resulted in synergistic antiproliferative effects. After cessation of the combination treatment all tumors resumed growth, initially with a low doubling time, but finally with their original growth rate. Gamma-interferon treatment initiated at a tumor volume of 0.2 to 0.5 cm.3 had no antitumor effects, whereas treatment with 100 micrograms. tumor necrosis factor per rat inhibited tumor growth significantly. Different combinations of the cytokines had synergistic effects against established tumors. These studies demonstrate antitumor effects of gamma-interferon and tumor necrosis factor in a rat bladder tumor model system. Combination therapy has synergistic effects and prolongs the time to tumor recurrence.

Animals↗

PubMed1991

Synergistic antitumor effects of rat gamma-interferon and human tumor necrosis factor alpha against androgen-dependent and -independent rat prostatic tumors.

We have examined the antitumor effects of rat gamma-interferon (IFN-gamma) and human tumor necrosis factor alpha (TNF) against androgen-dependent and -independent Dunning rat prostatic tumors. In vitro studies, using the double layer soft agar assay, showed a very limited antiproliferative activity of the drugs in the dose range tested (1-1000 units IFN-gamma and/or 1-1000 ng TNF/dish). For in vivo studies IFN-gamma and TNF were administered s.c., peritumorally. IFN-gamma was given 3 times/week, 8,000 or 80,000 units/rat, and TNF 5 times/week, 10 or 100 micrograms/rat. IFN-gamma and TNF monotherapy were not significantly effective in inhibiting tumor growth, except for IFN-gamma against the androgen-independent MatLyLu tumor. Combinations of IFN-gamma and TNF had synergistic antiproliferative effects against all four tumor lines tested; however, complete growth inhibitions could not be achieved. Survival studies showed significant increase in survival of tumor-bearing rats.

Androgens↗

PubMed1990

[The treatment of kidney and ureteral stones using a second-generation kidney stone lithotriptor].

In January 1988 a Siemens Lithostar lithotriptor was installed in the Radboud University Hospital in Nijmegen. Over 1600 treatments have been performed since. The results of 582 treatments of the first 500 patients are discussed. After three months 51.3% of the patients were free of stones. After six months this percentage was 64.5 and in addition 25.4% of the patients were free of symptoms although residual particles were still present. In only 10.1% of the patients did the ESWL treatment not succeed. In over 50% of the cases treatment was performed on an outpatient basis. Among 90% of the patients in whom treatment was performed without auxiliary procedures only 50% needed i.v. sedation or analgesia. The other 50% did not need any form of sedation or analgesia. Major complications did not occur although 376 patients (75.2%) suffered from a short period of haematuria and many patients had a skin lesion. With the possibility of outpatient treatment, the use of less anaesthesia and a success rate of 89.9% (residual stones, less than 5 mm in diameter, which can be evacuated spontaneously) after six months, the Lithostar is an improvement in the treatment of urolithiasis.

Adolescent↗

PubMed1990

In vivo antiproliferative effects of gamma-interferon and tumor necrosis factor alpha in a rat renal cell carcinoma model system.

We have investigated the antiproliferative activities of recombinant rat-gamma-interferon and recombinant human tumor necrosis factor alpha in a rat renal cell carcinoma model system. The tumor was transplanted subcutaneously, the drugs were administered peritumorally. Gamma-interferon treatment starting two days after tumor implantation resulted in a dose-dependent growth inhibiting effect. Tumor necrosis factor alpha was only effective at the highest concentration. Different combinations of the drugs have additive or synergistic antiproliferative effects. The combination of both highest doses completely inhibited tumor growth without any obvious toxic effects on the rats. Rechallenge of the cured rats with a tumor piece in the contralateral flank did not result in a tumor specific immune response. Shortening of the treatment period to two weeks resulted in an increased lag-period, but finally all tumors started to grow. Furthermore, the anti-tumor effect was dependent on tumor volume at start of therapy. Monotherapy could not inhibit tumor growth of an established tumor. The combination with both highest doses, however, inhibited tumor growth even when treatment was started at a tumor volume of two to five cm3. Treatment with gamma-interferon and tumor necrosis factor is most effective at low tumor burden. These studies suggest that clinical application of these drugs is most effective in an adjuvant setting.

Animals↗

PubMed1988

Effect of alpha- and gamma-interferon and tumor necrosis factor on colony formation of two human renal tumor xenografts in vitro.

The in vitro antitumor activity of alpha- and gamma-interferon as well as tumor necrosis factor was tested on two human renal cell carcinoma xenografts--RC-43 and NC-65. A dose-dependent inhibition of colony formation in soft agar was found for both tumor lines. NC-65, however, showed no sensitivity for gamma-interferon. Combination drug tests showed a synergistic effect on colony formation of both tumor lines. The strongest inhibition was shown by the combination of alpha-interferon and tumor necrosis factor. We conclude that both interferons as well as tumor necrosis factor show direct in vitro cytostatic effects against renal tumor direct in vitro cytostatic effects against renal tumor cells.

Animals↗

PubMed1988

In vitro antiproliferative efficacy of interferon-alpha, -gamma and tumor necrosis factor on two human renal tumor xenografts.

The in vitro antitumor activity of recombinant alpha- and gamma-Interferon as well as recombinant Tumor Necrosis Factor alpha was tested on renal cell carcinoma xenografts using the double layer soft agar method. Using this assay, the effect of the drugs on the clonogenic potential of tumor cells in soft agar was determined and used as an indication for the antiproliferative capacity of these drugs. There appeared to be a differential response of the tested xenografts towards these drugs in a dose dependent way. However, when used in combination in most cases an additive or synergistic effect was observed. Even though again the response was differential, the combination of alpha-Interferon (10 ng/dish) and Tumor Necrosis Factor (100 ng/dish) resulted in a complete inhibition of colony formation in soft agar for both tumor lines. We conclude that there is a direct effect of alpha-Interferon, gamma-Interferon and Tumor Necrosis Factor on renal cell carcinoma xenografts. In combination drug tests the effect of alpha-Interferon and Tumor Necrosis Factor was strongly synergistic. The implication of these studies for in vivo use of these drugs remain to be established.

Animals↗

PubMed1986

The effects of intravesical and intradermal application of a new B.C.G. on the dog bladder.

Intravesical and intradermal application of B.C.G. (Bacillus Calmette Guérin) has proven to be effective in the prophylaxis of recurrence of superficial bladder carcinoma after transurethral resection and in the treatment of carcinoma in situ (C.I.S.) in man. Different strains of B.C.G. have been used for this purpose. In this article a new strain of B.C.G. (B.C.G.-R.I.V.M.) has been tested to assess its toxicity. The effects of intravesical and intradermal application of B.C.G.-R.I.V.M. were studied on normal and on coagulated canine urothelium. In this study no general side effects of B.C.G.-R.I.V.M. were seen. Only minor local changes occurred in the bladder wall. Small granulomas were found in the suburothelial tissue. No granulomas or signs of active inflammation were observed in the pelvic lymphnodes, spleen and liver. Because B.C.G.-R.I.V.M. seemed to be a safe agent in the dog we have started to use it for prophylaxis in superficial bladder cancer in man.

Administration, Intravesical↗

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↗