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F M Debruyne

Publications and source records attributed to F M Debruyne.

At least 181 records · Page 10Linked to original sources
PubMed1995

Modelling selective activation of small myelinated nerve fibres using a monopolar point electrode.

The aim of this study is to investigate theoretically the possibility for activation of small myelinated nerve fibres without activating larger ones when stimulating a nerve fibre bundle using a monopolar point electrode. Therefore, the sensitivity of excitation and blocking threshold currents of nerve fibres to fibre diameter, electrode-fibre distance and pulse duration has been simulated by a computer model. A simple infinite, homogeneous volume conductor and a cathodal point source were used in combination with a model representing the electrical properties of a myelinated nerve fibre. The results show that selective activation of small myelinated fibres may be possible in a region at some distance from the electrode.

Computer Simulation↗
PubMed1995

Factors affecting recurrence and progression in superficial bladder tumours.

Prognostic factors in superficial bladder tumours are highly correlated with each other. In this study, their relative importance is examined and grouping of patients in three different prognostic groups suggested. 576 patients (from EORTC protocols 30790 and 30782) were analysed. They have been followed from 3 months to 8.6 years with a median of 4 years. 76 patients developed an invasive tumour (> or = T2); the shortest time to invasion was 12 weeks, the longest was 6.6 years. Time from invasion to death ranged from 3 weeks to 4.4 years with a median of 2 years. Prognostic factors contributing to recurrence, invasion and survival were investigated: age, sex, size of largest tumour, number of tumours, T-category, G-grade, time from diagnosis (years), prior recurrence rate/year, site of involvement. The relative importance of these factors was measured by performing a multivariate analysis based on Cox's proportional hazards regression model. Based on the most important prognostic factors and their association with invasion and death, an index was computed reflecting the risk of both invasion and death due to malignant disease, respectively. The index was used to assign patients to one of three prognostic groups. Three main factors determined patient's prognosis: tumour size, G-grade and prior recurrence rate/year. The model coefficients for invasion were 0.51 (recurrence rate < 1/year, 1-3/year, > 3/year), 84 (grade 1, 2, 3), 0.48 (size < 1.5, 1.5-3, > 3 cm) and for death due to malignant disease 0.89 (recurrence rate), 0.73 (grade) and 0.44 (size), respectively. Risk groups are suggested based on the index. Additional treatment in patients with superficial transitional cell carcinoma of the bladder may be decided depending on the risk group to which the patient belongs.

Adolescent↗
PubMed1995

Risk factors in carcinoma in situ of the urinary bladder. Dutch South East Cooperative Urological Group.

OBJECTIVES: In this article we describe the long-term follow-up of patients with carcinoma in situ (CIS) of the urinary bladder and examine whether the extent of CIS, the presence of associated papillary tumors, or the response to treatment influence the course of the disease. METHODS: Fifty-two patients with CIS of the bladder, treated in a randomized prospective study, are described. In 23 patients with concomitant papillary tumors all macroscopically visible lesions were completely resected transurethrally (TUR). CIS was histologically confirmed in all patients by biopsy, 29 of whom had primary CIS. The patients were treated with intravesical mitomycin, bacille Calmette-Guérin (BCG)-RIVM or BCG-Tice and followed regularly by urine cytology, cystoscopy, and biopsy. RESULTS: Complete response was achieved in 65% of the patients. Of these responders, 24% later had a recurrence of CIS or a superficial tumor and 18% had progressive disease (PD). In the nonresponding patients, progression occurred in 67%. In the whole group, PD was seen in 35% of the patients, and radical cystectomy was performed in 21%. The disease-related death rate was 13%. The risk for recurrence or PD was not higher in patients with more extensive CIS, defined as three or more positive biopsy results or when CIS was associated with papillary tumors compared to patients with one or two biopsy specimens positive for CIS or CIS alone. Nonresponding patients showed a significantly higher progression rate and cystectomy rate than responding patients (P = 0.0012 and 0.008, respectively). CONCLUSIONS: CIS of the bladder is a malignancy with a poor prognosis, especially in patients not responding after intravesical treatment. Early detection and adjuvant intravesical treatment after TUR of concomitant papillary tumors are required. In patients not responding after intravesical treatment, radical surgery is necessary before progression occurs. The number of biopsies positive for CIS, not the presence of concomitant superficial tumors, was an indicator for progression or recurrence.

Carcinoma in Situ↗
PubMed1995

The effects of successive high-energy shock-wave tumor administration on tumor blood flow.

The effects of repeated high-energy shock wave (HESW) tumor administration on tumor blood flow (TBF) were studied in NU-1 human kidney cancer xenografts. Deuteriated water was used as a magnetic resonance spectroscopic detectable tracer for measuring tumor blood flow. Tumors were exposed twice to 800 electromagnetically generated HESW, with a 24-h interval or sham exposed. No changes in TBF occurred after sham exposure to HESW. TBF levels 2 h after the first and second HESW application were, respectively, 46% and 37% lower than the mean preexposure TBF value and returned to normal levels within 16 h. There was statistically no difference found between the effects on tumor blood flow after the first and second HESW exposure. These observations are in agreement with earlier studies and provide a rationale to shorten the time interval between HESW monotreatments to 2 to 3 h.

Animals↗
PubMed1995

Planimetric volumetry of the prostate: how accurate is it?

Planimetric volumetry is used in clinical practice when accurate volume determination of the prostate is needed. The prostate volume is determined by discretization of the 3D prostate shape. The are of the prostate is calculated in consecutive ultrasonographic cross-sections. This area is multiplied by the distance between the cross-sections and the total volume is determined by summation of all contributions. Besides the quality of the automated outlining, the accuracy of this method depends on this intersection distance and on the angle of the scan plane with the probe. Also, the location of the first cross-section is of influence. This paper describes the influences of these parameters on the accuracy of the volume determination using a simple prostate model. This theoretical influence is compared to clinical volume determinations using automated planimetric volumetry with different step sizes. From our data, it is concluded that a step size of 4 mm for planimetric prostate volume determination is a good compromise between investigation time and accuracy in a clinical setting.

Humans↗
PubMed1995

Urodynamic results of laser treatment in patients with benign prostatic hyperplasia. Can outlet obstruction be relieved?

PURPOSE: A urodynamic study was done to judge the capability of laser treatment to relieve bladder outlet obstruction. MATERIALS AND METHODS: Advanced urodynamic studies with pressure-flow analysis were performed before and 6 months after laser treatment using 3 different laser devices. RESULTS: Forty patients showed significant improvement in all obstruction parameters (detrusor pressure at maximum flow rate, urethral resistance relation, theoretical cross-sectional urethral area, minimal detrusor pressure and linear passive urethral resistance relation) together with significant subjective improvement in international prostate symptom score. After treatment 82 to 92% of the patients could no longer be considered to have obstruction. No difference in outcome among the devices used was found. CONCLUSIONS: Laser prostatectomy is indeed capable of relieving bladder outlet obstruction.

Aged↗
PubMed1995

Computerized analysis of transrectal ultrasonography images in the detection of prostate carcinoma.

OBJECTIVE: To report on the use of automated image analysis in the interpretation of transrectal ultrasonographic images of the prostate. PATIENTS AND METHODS: During transrectal ultrasonography, images were recorded from biopsies performed in 127 patients. Subsequently in the image, the puncture place was marked and analysed. Analysis of the images was performed with the Automated Urologic Diagnostic Expert (AUDEX) system, consisting of a personal computer connected to the ultrasound machine. From the images collected, parameters can be calculated for image classification. The parameters obtained with this procedure were correlated with the histological result. RESULTS: Evaluation showed a sensitivity of 84.8% and specificity of 87.5%. The positive and negative predictive values, to predict prostate carcinoma, were 84.8% and 87.5%, respectively. CONCLUSION: Automated image analysis can help in the diagnosis of prostate carcinoma. In patients with non-palpable lesions or with poorly visualized tumours, image analysis is superior to the standard current diagnostic techniques.

Humans↗
PubMed1995

Urodynamic assessment in the laser treatment of benign prostatic enlargement.

OBJECTIVE: To determine if bladder outlet obstruction can be adequately relieved after laser prostatectomy. PATIENTS AND METHODS: Since November 1992, a total of 105 patients underwent laser treatment of the prostate because of complaints related to benign prostatic enlargement (BPE). To date, urodynamic data from a study of pressure flow analysis are available for 79 patients both at baseline and at 6 months after treatment. Patients were evaluated using changes in symptoms (IPSS symptom score), peak flow rate (Qmax), post-voiding residual volume (PVR), detrusor pressure at maximum flow (Pdet at Qmax), and the linear passive urethral resistance relation (LPURR). Moreover, patients with minimal bladder outlet obstruction were compared to patients with severe bladder outlet obstruction. RESULTS: There was a significant improvement in mean IPSS score from 21.3 at baseline to 5.3 at the 6-month follow-up. The Qmax improved from 7.9 mL/s to 17.8 mL/s, and the PVR decreased from 91.6 mL to 15.6 mL. At baseline, > 80% of the patients were considered obstructed according to the analysis of pressure flow, whereas 6 months after laser treatment, only 5% of the patients were still considered obstructed. A comparison of the outcome between minimally obstructed patients and severely obstructed patients showed comparable improvements. CONCLUSION: Laser therapy of the prostate was, according to urodynamic parameters, capable of relieving outlet obstruction and minimally obstructed patients also showed a significant relief of outlet obstruction.

Humans↗
PubMed1995

Advances and trends in hormonal therapy for advanced prostate cancer.

Hormonal therapy represents first-line treatment for patients with advanced prostate cancer. Generally, surgical castration is viewed as the 'gold standard' but carries with it a psychological effect. Medical alternatives include LHRH analogues, antiandrogens, and oestrogens, though the last of these is associated with cardiovascular problems. For complete androgen ablation, it is generally believed that androgens of both testicular and adrenal origin need to be blocked. Combined androgen blockade (CAB) by the addition of antiandrogen to castration (medical or surgical) may, therefore, be an appropriate treatment for advanced prostate cancer. Recent trials have shown that CAB may have treatment advantages compared with castration alone, and these benefits are greatest in patients with minimal metastatic disease. For these patients CAB may now be considered as standard therapy. In the treatment of non-metastatic disease, recent trends based on the experience gained in advanced prostate cancer include the possible use of hormonal therapy in neoadjuvant and adjuvant settings along with prostatectomy or radiotherapy. There is also growing interest in the use of intermittent rather than continuous hormonal therapy. New treatments offer an increasing range of management options to help improve the quality of life of prostate cancer patients.

Androgen Antagonists↗
PubMed1995

A randomised trial comparing the safety and efficacy of the Zoladex 10.8-mg depot, administered every 12 weeks, to that of the Zoladex 3.6-mg depot, administered every 4 weeks, in patients with advanced prostate cancer. The Dutch South East Cooperative Urological Group.

A new longer-acting depot formulation containing 10.8 mg Zoladex administered every 12 weeks was compared to the 3.6-mg Zoladex depot administered every 28 days, in a randomised trial in patients with advanced prostatic carcinoma in which pharmacodynamic efficacy and safety were assessed. Effective induction of mean serum testosterone suppression into the surgically castrate range by 21 days and maintenance of suppression for the duration of therapy was achieved with both the 3.6-mg and the 10.8-mg depot formulations. The Zoladex 10.8-mg depot was well tolerated both locally and systemically. This new formulation which is equivalent to three successive 3.6-mg depots will provide a more convenient dosing regime for both patient and doctor in this indication.

Aged↗
PubMed1995

Automated analysis and interpretation of transrectal ultrasonography images in patients with prostatitis.

Transrectal ultrasound (TRUS) offers a valuable complement to digital rectal examination (DRE) in diagnosing prostate diseases. However, in case of prostatitis syndromes, contradictions are found with regard to characteristic ultrasound features in these patients. Therefore we sought for better imaging techniques. This paper describes a study on the automated analysis of ultrasonographic prostate images (AUDEX). With image processing, in the present study, tissue characterization is performed to predict the probability of the presence of inflammated prostate tissue. This technique already proved its validity in patients with prostate cancer. During prostate examinations, images were recorded with clear indication of the puncture position. Only patients with an unambiguously inflamed or noninflamed benign histologic result were included. Evaluation showed that a sensitivity of 90.6% and a specificity of 64.2% was reached. Finally, the prospective positive and negative predictive value for prostatitis was 50.0% and 94.6%, respectively. This means that AUDEX predicts the diagnosis 'prostatitis' in a large number of patients with no infection. In case of prostatitis, however, this prediction is almost always right.

Data Interpretation, Statistical↗
PubMed1995

Bacillus Calmette-Guérin in superficial bladder cancer: consensus and controversies.

In this overview, Bacillus Calmette-Guérin (BCG) immunotherapy in superficial bladder cancer items are discussed on which consensus has been reached and on which controversies exist. The evaluation of the optimal route of administration has shown that intravesical instillation of BCG alone is accepted as the best route of administration. In searching for the appropriate BCG strain, the analysis of the results of 6 substrains has made clear that no particular strain has shown superiority over others. In finding the optimal treatment schedule there is strong evidence that maintenance therapy is superior to induction therapy alone. No consensus has been reached about the optimal dose for BCG therapy nor about how the toxicity of BCG treatment can be reduced. Although some reports have stated that BCG immunotherapy is superior to chemotherapy for the treatment of patients with superficial bladder cancer, more data are needed to prove this statement. In conclusion, although BCG has been proven to be very effective in the treatment of patients with superficial bladder cancer, it is certainly not a panacea for all patients with superficial bladder cancer.

Administration, Intravesical↗
PubMed1995

Improved subjective responses to orchiectomy plus nilutamide (anandron) in comparison to orchiectomy plus placebo in metastatic prostate cancer. International Anandron Study Group.

Patients with advanced prostate cancer have a beneficial effect from maximal androgen blockade in terms of the subjective and objective delay of progression and median duration of survival, although side effects do occur more often in the combination treatment than in testicular suppression alone. Significant improvement or delayed deterioration in subjective parameters such as metastatic pain, performance status and urinary disorders strongly suggest (in the absence of validated questionnaires of quality of life at the time of this study) that orchiectomy plus nilutamide improves the quality of life as assessed by the subjective delay of progression, according to NPCP criteria, to an extent which outweighs the majority of adverse events.

Adult↗
PubMed1995

Analysis of maximum detrusor contraction power in relation to bladder emptying in patients with lower urinary tract symptoms and benign prostatic enlargement.

PURPOSE: We evaluate the relationship among post-voiding residual urine volume, bladder outlet obstruction and maximum detrusor contractility power. MATERIALS AND METHODS: We investigated urodynamically and retrospectively 242 elderly men with various grades of bladder outlet obstruction and symptoms. RESULTS: Residual urine predominantly correlated with bladder outlet obstruction and not with maximum detrusor contractility power. Maximum detrusor contractility power showed significant positive correlation with bladder outlet obstruction. Urodynamically, the detrusor compensates for bladder outlet obstruction with elevated maximum detrusor contractility power. Decay of contraction during micturition however, hampers effective emptying. CONCLUSIONS: Maximum detrusor contractility power limits for normal detrusor contractility must be related to bladder outlet obstruction grade. Based on the results of our analysis, new limits showing improved correlation with complete emptying were derived.

Aged↗
PubMed1995

Expression of markers for transitional cell carcinoma in normal bladder mucosa of patients with bladder cancer.

PURPOSE: Because we have found that random mucosal biopsies have no additional prognostic value to conventional histopathology, we studied biopsies of histologically normal bladder mucosa with several molecular markers believed to be associated with the development of transitional cell carcinoma. MATERIALS AND METHODS: Six groups of patients with an increasing stage of bladder tumor were selected: (1) benign disease (for example, benign prostatic hyperplasia, n = 8); (2-4) low (n = 10), intermediate (n = 9) and high risk (n = 7) superficial tumors; (5) progressive superficial tumors resistant to optimal conservative therapy (n = 6); (6) invasive or disseminated tumors at presentation (n = 5). We studied the expression of cytokeratin (used as an epithelial marker), fibronectin, E-cadherin (HECD-1), I-CAM, human leukocyte antigen (HLA)-I, HLA-II and epidermal growth factor receptor (EGF-R) in cold-cup biopsies of normal mucosa. RESULTS: Fibronectin, HECD-1, I-CAM and HLA-II expression showed no significant changes in the different groups. There was a significant increase in the expression of HLA-I (p = .003) and EGF-R (p = .0001) with a higher stage of the tumor. CONCLUSION: An increasing EGF-R expression in normal looking mucosa of patients with increasing stages of bladder tumors could be a prognostic factor or might indicate that this increase in expression is not tumor specific but is seen in the whole bladder.

Biomarkers, Tumor↗
PubMed1995

Variability of pressure-flow analysis parameters in repeated cystometry in patients with benign prostatic hyperplasia.

Urodynamic investigation becomes increasingly important in the diagnosis of bladder outflow obstruction in patients with benign prostatic hyperplasia. To date, different methods for evaluation of the pressure-flow relationship and quantification of the grade of obstruction are available. Models for pressure-flow analysis are briefly explained. The variability of the parameters is investigated by evaluation of 75 patients in whom 2 sequential voidings during urodynamic investigation were analyzed. The results showed that in 87% of these patients individual maximum flow differences of first and second voidings were less than 2 ml. per second. Individual detrusor pressure at maximum flow differences were less than 15 cm. water in 80% of these patients, while in 80% the intra-individual variation of the pressure-flow results was less than 15 cm. water for the minimal voiding pressure parameters (minimal urethral opening detrusor pressure and urethral resistance factor). For the pressure-flow parameter that defines the theoretical urethral lumen during voiding, the variation was less than 1.5 mm.2 in 84% of the patients. Patients with larger intra-individual differences are discussed. We concluded that the observed, aforementioned differences can be regarded as an indication of normal intra-individual variability of voiding during urodynamic investigation. This intra-individual variability, however, seldom leads to a change in the clinical grade of bladder outflow obstruction. We conclude that investigators involved in therapeutic trials of benign prostatic hyperplasia must be aware of this intra-individual variability of micturition, since this variability is greater than the refined scale of the pressure-flow analysis models.

Humans↗
PubMed1995

Automated prostate volume determination with ultrasonographic imaging.

A method for automated determination of the prostate volume based on planimetric volumetry was developed to overcome subjectivity in prostate volume measurements using ultrasonography. An edge detection method is applied to locate the prostate boundary in sequential ultrasonographic images. During regular examinations, the volume was assessed automatically in 55 patients. The Pearson correlation coefficient of the automated volume compared to the reference prostate volume was 0.93. The estimated ratio of the automated volume to the reference volume was 0.92. This method overcomes the individual subjectivity when interpreting ultrasonographic images, and provides accurate and objective results for followup of benign prostatic hyperplasia treatments and for comparison of multicenter trials. Also, this method is a useful tool for objective determination of prostate specific antigen in proportion to the volume (prostate specific antigen density).

Aged↗