Biomedical subjects
Publications and source records attributed to J D de Vries.
We present a rare complication causing severe infravesical obstruction after hypospadias repair after an initially successful double-faced island flap repair. The obstruction was caused by partial dissection of the epithelium of the urethral wall, comparable to intima dissection in an aortic aneurysm. To our knowledge, this type of urethral obstruction after a hypospadias repair has not been reported before.
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OBJECTIVE: This study is a retrospective analysis of the outcome of our one-stage hypospadias corrections. PATIENTS AND METHODS: In the period from August 1979 to January 1991, 316 boys less than 14 years of age underwent a one-stage hypospadias correction in our hospital. For 283 patients, data on the familial incidence, associated urological pathology, age at the time of operation, operation technique and follow-up were analyzed. RESULTS: The familial incidence in our study group was 9.4%, associated cryptorchidism was seen in 8.6%, kidney abnormalities in 1.8% and urethral valves in 0.4%. The majority (65.3%) of the children were operated on before the age of 3 years. The operation was performed according to Magpi, Mathieu, Devine-Horton, an onlay, and tube formation according to Duckett and the double-faced island flap procedure. Including all postoperative disturbances, urethral complications were seen in 18.1% and skin-related complications in 4.6% of the patients. CONCLUSION: Even in experienced hands the overall complications rate is relatively high, and additional problems can be expected in the future. It is important to provide adequate information on the procedures and possible complication to the parents. The final long-term outcome after puberty has to be awaited.
OBJECTIVE: To inventory symptoms of children with urethral valves, and their prognosis. DESIGN: Descriptive. SETTING: Department of paediatrics and urology, University of Nijmegen. METHODS: Symptoms were evaluated from clinical data and interviews of the parents of 73 patients. The glomerular filtration rate (GFR) was calculated from the serum creatinine level by the method of Counahan. RESULTS: Symptoms indicating an urethral obstruction, e.g. diminished urinary jet, were rare (20% of the children). General symptoms prevailed: vomiting, anorexia, growth failure, fever. After 2 years 11 out of 53 children had a GFR < 25 ml/min/1.73 m2 body surface area. CONCLUSION: Specific symptoms indicating an urethral obstruction are rare. The glomerular filtration is often diminished. There are no measures to prevent loss of renal function.
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Even though rhabdomyosarcoma is the most common soft tissue sarcoma in children, accounting for 5-10% of all malignant disease in children under 15 years of age, so few cases are seen in a single institution that only the combined efforts of multicentre prospective trials made it possible fro adequate treatment schedules to be devised. Thank to this cooperation, survival rates have increased dramatically in recent decades; risk factors have been identified and treatment can now be adapted accordingly. This is especially true for the paratesticular rhabdomyosarcoma (PTRM), which now has a good prognosis in all stages. The striking similarity of tumor behavior and metastatic pathways to those in germ-cell tumors in young male adults can provide us with more extensive data derived from a much larger group of patients. Recent data are gathered and evaluated in this review. Only in this way will it be possible to eliminate all treatment modalities known to be followed by severe sequelae, thus avoiding exposure of the patients to a therapy that carries more risks than the primary tumor itself.
Five cases of bilateral ureteral obstruction after appendicectomy are presented. All five patients were boys (age range, 9 to 15 years). All of them had had severe appendicitis. Based on the urethrocystoscopy findings, edema of the posterior bladder wall appeared to be the cause of obstruction of both distal ureters. This is confirmed by the immediate recovery of renal function after installation of bilateral uretercatheters. It is known that contamination of the peritoneal cavity can occur by organisms leaking from a gangrenous or perforated appendix. This can cause localized inflammatory edema of the posterior bladder wall. It is remarkable that through ultrasound investigation, only mild to moderate dilatation of the urinary tract was observed. An explanation can be obtained from animal models, wherein acute obstruction of the ureter leads only to a transient increase in ureteral pressure, followed by a decline toward the preobstruction level. It is important to be aware that this complication can occur after appendectomy; bilateral uretercatheters can be installed, and irreversible renal damage can be avoided.
PURPOSE: The use of intracerebral microdialysis as a tool to measure the penetration of anticancer agents in brain tumor was investigated. METHODS: Following intravenous (iv) administration of 75 mg/kg. concentration-time profiles of methotrexate (MTX) were determined in brain cortical dialysate and in plasma. The individual ratio of the area under the curve of MTX in brain dialysate over that in plasma (MTX penetration) was determined in normal brain, in tumor-bearing brain and in brain after sham tumor implantation. Individual brains were examined histologically on the presence of tumor, as well as for other factors that might influence local MTX penetration. Histological scores were related to the individual data on penetration of MTX. RESULTS: MTX penetration values were higher in cortical brain at the site of the tumor, as compared to the levels measured in normal or sham implanted brain (mean increase to 250%). In the cortical brain contralateral to the tumor, MTX penetration values were found to be lower than in normal brain (mean reduction of 65%). Furthermore, it appeared that in the absence of tumor tissue, the presence of exudate around the probe was independently associated with increased penetration of MTX into the brain. CONCLUSIONS: Tumor tissue appeared to be the most important parameter in changing local MTX penetration in brain after tumor implantation. In general, it is anticipated that intracerebral microdialysis combined with histological examination can be used to investigate effects of brain tumor presence on regional (periprobe) penetration of anticancer drugs into the brain.
This is a study about the current status of knowledge and level of insight in treatment possibilities of pediatric urological diseases in daily practice of Dutch general practitioners (GPs). A questionnaire was mailed to GPs with questions concerning the structure of their medical practice, the localization, the received education in pediatric urology and knowledge of this subspeciality. Also, questions were asked about their current knowledge and first choice of treatment for maldescensus testis, urinary tract infections, enuresis nocturna and congenital abnormalities. The 995 forms that were returned, representing 1,457 GPs, are discussed. New developments in diagnostic procedures and treatment possibilities should be reflected in the exchange of information between GPs and (sub)specialists. However, before changes can be realized, the current knowledge and opinions should be known. This study investigates the current opinion of GPs of different pediatric urological diseases. Additionally, the incidence and current state of the art in diagnosis and treatment are discussed.
Cryptorchidism is the most common male sexual disorder. In the case of an abdominal testis there is no objective criterion to choose between autotransplantation or orchiopexy after ligation of the spermatic vessels with subsequent development of collateral blood supply. By combining near infrared spectroscopy (NIRS) with pulse oximetry the active testicular blood volume (ATBV) before and after occlusion of the spermatic vessels can be calculated in an animal model. NIRS is a noninvasive continuous optical technique that measures tissue oxygenation and hemodynamics. Ten boars with one non-palpable testis each were selected. The spermatic vessels and vas deferens were separately prepared and atraumatic occluders were placed around the vessels. ATBV was measured before and after occlusion of the spermatic vessels. The calculated ATBV was 18.3 +/- 2.3 ml/100 g of testicular tissue, not corrected by division by the path length factor, accounting for light scattering in the tissue. In 5 of 10 boars no significant ATBV was found after occlusion of the spermatic vessels, suggesting subsequent atrophy. NIRS combined with pulse oximetry provides us with reproducible quantification of ATBV. The method can be used to investigate the viability of a testis after (temporary) occlusion of the spermatic vessels.
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Chlorzoxazone is 6-hydroxylated by cytochrome P450 2E1 (CYP 2E1), which bioactivates many toxic and carcinogenic molecules. Seventeen volunteers of varying age, ethnicity, and gender received a 250 mg tablet of chlorzoxazone and their blood and urine were sampled frequently for 8 h. V/F = 42 +/- 21 L and CL/F = 412 +/- 120 mL min-1. Comparison of these values with a study by other investigators using a suspension dosage form suggested that relative Ftablet approximately 0.7. The fraction excreted in the urine as 6-hydroxychlorzoxazone (fe,6-OH) was 0.39 +/- 0.20 and that portion of the total CL accounted for by CYP 2E1-mediated metabolism (CL6-OH) was 163 +/- 95 mL min-1. Thus, while V/F and CL/F varied by factors of less than five, fe,6-OH varied 16-fold and CL6-OH varied 28-fold. These results suggested that there was considerable inter-individual variability in the metabolism of chlorzoxazone to 6-hydroxychlorzoxazone. This variability will significantly affect the construction of physiologically based pharmacokinetic models that use the 6-hydroxylation of chlorzoxazone as a marker for an individual's CYP 2E1 phenotype.
OBJECTIVE: To show the reliability of laparoscopic procedures in case of cryptorchidism. It also shows the growing possibilities of laparoscopic manipulations of the cryptorchid testis obviating in a great percentage the need for open operative procedures. METHODS: Starting from the standard diagnostic laparoscopic procedure we gradually extended its use to a full operative procedure. The standard procedure is extensively elucidated in the way we used it in sixty-one laparoscopic procedures for seventy-four non-palpable testes. RESULTS: All laparoscopies were technically successful. Forty testes (60.3%) were found intra-abdominally. Four testes (5.5%) were found lying in the inguinal canal or in an ectopic position. Twenty-five testes were absent. The diagnosis of a vanishing testis could be established in most of these cases. In the beginning period the following open procedures were done after the diagnostic laparoscopy: sixteen open explorations, ten formal standard orchidopexies; nine orchiectomies, nine autotransplantations, and three Fowler-Stephens procedures. In recent years we proceeded with laparoscopic manipulation, performing eleven laparoscopically assisted orchidopexy procedures (LAOPs), six extended laparoscopic explorations, and two laparoscopic orchiectomies. CONCLUSIONS: Laparoscopy is not only a safe and reliable method in diagnosing the presence of a nonpalpable testis, but also thanks to more sophisticated instruments allows us more and more to perform the complete treatment. It can facilitate the placement of surgical incisions or obviate the need for further open intervention if no spermatic vessels are visualized in the abdomen.
Since sonographic evaluation of the fetus became routine, prenatally established diagnosis of multiple or severe malformations raises the question of whether a pregnancy should be terminated. To answer this question properly, all aspects concerning the life of a child born with a serious malformation, such as exstrophy of the bladder, must be considered. Therefore, more than ever an evaluation of the quality of life of these patients is necessary to be able to make a solid based decision. We studied the psychosexual and socioeconomic development of 22 adult exstrophy patients (11 men and 11 women) by a standardized personal interview, evaluation of a standard performance test SCL-90 (symptom checklist 1990) and an adapted personality score test. The latter 2 tests are well established and provide reproducible results. Based on several large scale investigations, standard scores are available. Nine women (82%) and 10 men (91%) scored better or in accordance with the standard scores. Exstrophy of the bladder does influence the psychosexual and socioeconomic development. The quality of life is hardly ever considered so poor that termination of pregnancy is a realistic alternative.
In this article we present our experience with diagnostic laparoscopies in 45 patients with a total of 48 impalpable testes. Laparoscopy was performed before surgical exploration, in the same operative set-up. No complications were seen. One laparoscopy was a technical failure. In six children and one adult no testis, no deferent duct or spermatic vessels were found. The diagnosis of testicular absence was made. In 14 children no testis was found. In 13 cases atrophic spermatic vessels were seen, in one case histologically proven testicular tissue was found. In one case a blind-ending deferent duct was seen. In 27 patients an intra-abdominal testis was found, mostly 2-3 cm before the internal annulus. We performed an orchidectomy 10 times, an orchidopexy 3 times and an autotransplantation of the testis 9 times. Laparoscopy proved to be an easy, safe and reliable method to localise an impalpable testis. It is the method of choice in our clinic.
We reviewed our experience with the pedicled island flap technique in severe urethral strictures, especially in regard of the long-term follow-up of functional parameters: micturition patterns and sexual behavior. Analysis of 59 consecutive cases treated with this approach has proven the value of this technique. The results of a questionnaire and the current clinical status showed that, of the 59 cases, 12 patients were subjectively dissatisfied with their micturition, independent of the results of functional voiding measurements, and 2 patients complained of impaired potency: 1 immediately after the original trauma, the other after the surgical repair. The most frequent reported micturition complaints were only minor: dribbling, nycturia and frequency, mostly already existing before the operation. The objective results, obtained postoperatively by uroflowmetry were good, but often did not correlate with the subjective results. The overall results are satisfactory. Only 3 patients replied to say that they regret having had the open operative procedure.
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Many techniques have been described for the repair of recurrent urethral strictures. Experience with 1-stage correction of hypospadias and epispadias, using a vascularized island flap technique, has led to its increased application for complicated adult urethral strictures. The advantage of the vascularized island flap technique is that reconstruction can be completed with only 1 operation, and it provides good subjective and objective results. Analysis of 50 consecutive cases treated by this approach has proved its validity. Of the 50 cases fistulas occurred in 20%, of which 12% required surgical correction, and stricture recurred in 32%. The largest proportion of recurrence was noted in patients who were primarily treated with 3 or more urethrotomies within a short time. Therefore, we recommend open surgical repair when 1 or 2 internal urethrotomies fail to produce a good result.