Papers by Ger van Venrooij
Ultrasonics, 1971
This paper describes a method of measuring ultrasound velocity to high accuracy in small samples ... more This paper describes a method of measuring ultrasound velocity to high accuracy in small samples of reasonably homogenous substances. Results obtained with some body fluids and brain tumours are given.
Acta Neurochirurgica
More than two hundred patients with intracranial lesions were examined by means of B-scan echo eq... more More than two hundred patients with intracranial lesions were examined by means of B-scan echo equipment specially adapted for the detectionof weak reflections. An impression of the accuracy of the method is demonstrated by the results obtained in those patients where the diagnosis had been verified at surgery or autopsy. It appeared that B scanning is a quite reliable diagnostic method. It was found that intracranial tumours showed typical echo-patterns. Furthermore, we found that B scanning may be an important diagnostic aid in follow-up examinations of patients. However, the ultrasound technique as used by us has also a restriction: it is unsuited for the estimation of the precise extension of pathological areas and for the estimation of the nature of pathology.
The Journal of Membrane Biology, 1974
The Journal of Membrane Biology, 1974
Incubation of the salivary glands of the larvae of Drosophila hydei in a control medium containin... more Incubation of the salivary glands of the larvae of Drosophila hydei in a control medium containing 2 x 10 -3 M cyclic adenosine monophosphate (cAMP) induces a considerable increase in passive electrical cell communication. This is caused by a decrease in permeability of the nonjunctional membrane part, together with an increase of the permeability of the low-resistance junctions. Similar changes in intercellular communication in the salivary gland of Drosophila hydei were seen in a majority of experiments in which 10-3M dibutyryl cyclic adenosine monophosphate (dBcAMP), 5 x 10 -3 M theophylline or ecdysterone (100/ag/ml) were added to the control medium. Hyperpolarization of the gland cells can be observed concomitant with the increase in communication. A hypothesis is discussed for a possible molecular regulation of passive electrical cell communication in which the intracellular cAMP level plays a significant part.
The Journal of Membrane Biology, 1973
International Urogynecology Journal, 1991
ABSTRACT
International Urogynecology Journal, 1990
ABSTRACT
European Journal of Obstetrics & Gynecology and Reproductive Biology, 1978
Biochimica et Biophysica Acta (BBA) - Biomembranes, 1975
Quantitative evaluation of the diffufion process of sodium fluorescein and dansylated amino adds ... more Quantitative evaluation of the diffufion process of sodium fluorescein and dansylated amino adds in the sMivary gland of the larvae of Drosophila hydei reveals that the differences in spedfic permeability between the junctional and nonjunctional membranes, as found for small ions, do not apply to the fluorescent probes. There are no fignificant differences between the permeability prope~ks for the different dansylated amino adds tested, and the same prope~s are found for sodium fluorescdn.
Acta Neurochirurgica, 1979
Anesthesia and Analgesia, 2008
Spinal local anesthetics interrupt the micturition reflex; bladder function remains impaired unti... more Spinal local anesthetics interrupt the micturition reflex; bladder function remains impaired until sensory block had regressed to the S3 segment. Intrathecal opioids cause dose-dependent suppression of detrusor contractility. We studied the effects of spinal anesthesia with a combination of lidocaine and sufentanil on lower urinary tract function. Filling cystometry was performed in 10 healthy young male patients undergoing elective lower limb orthopedic surgery. After baseline recordings, each patient received spinal anesthesia with 100 mg hyperbaric lidocaine combined with 20 microg sufentanil. In the postoperative phase, regressions of sensory and motor block were recorded and urodynamic measurements continued until the patient could void spontaneously without residual volume in the bladder. The mean (SD) time to recovery of urge was 240 (37) min after spinal injection, but no patient was able to void at that time. Six patients experienced urge at the previously observed maximum bladder capacity when the sensory block had regressed to the second sacral segment (S2), in four patients to S3. Despite this urge, no detrusor contraction was recorded. The patients were able to completely empty the bladder 332 (52) min after spinal injection. The average time difference between recovery of urge and return of normal bladder emptying was 90 min. Bladder contractility returns much later than recovery of sensory function in sacral dermatomes (S3) when hyperbaric lidocaine combined with sufentanil is used for spinal anesthesia.
Eur Urol, 2000
The aims of this study were to analyse the data from frequency-volume charts and to study the rel... more The aims of this study were to analyse the data from frequency-volume charts and to study the reliability of these charts in men with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH). Methods: Men with LUTS suggestive of BPH were consecutively included in the study if they met the criteria of the International Consensus Committee on BPH, voided more than 150 ml during uroflowmetry, residual volume and prostate size were estimated and frequency-volume charts were completed correctly. From the frequency-volume charts, voiding habits and fluid intake were evaluated. Results: 160 patients could be included. Another 28 patients who met all other criteria did not complete the frequency-volume charts correctly. Agreement exists between reported voided volumes in the literature and those found by us. We found a significant correlation (p<0.001) between nocturia and score on symptom question 7, and between diuria and score on symptom question 2 of the AUA symptom index. The difference between results obtained from frequency-volume charts completed during 24 h and those obtained from charts completed during three or more 24-hour periods was negligible with respect to the variation of data at an individual level. Conclusions: Frequency-volume charts are reliable in the investigation of patients with LUTS suggestive of BPH. Reporting on frequency-volume charts during just 24 h is sufficient to gain insight into their voiding habits during normal daily life.
The Journal of the American Society of Anesthesiologists, Jun 1, 2004
Intrathecal administration of opioids may cause lower urinary tract dysfunction. In this study, t... more Intrathecal administration of opioids may cause lower urinary tract dysfunction. In this study, the authors compared the effects of morphine and sufentanil administered intrathecally in a randomized double-blind fashion (two doses each) on lower urinary tract function in healthy male volunteers. Urodynamic evaluation was performed before and every hour after drug administration up to complete recovery of lower urinary tract function using pressure and flow measurements recorded from catheters in the bladder and rectum. Sense of urge and urinary flow rates were assessed every hour by filling the bladder with its cystometric capacity and asking the patient to void. Full recovery was defined as a residual volume of less than 10% of bladder capacity and a maximum flow rate within 10% of the initial value. Intrathecal administration of both opioids caused dose-dependent suppression of detrusor contractility and decreased sensation of urge. Mean times to recovery of normal lower urinary tract function were 5 and 8 h after 10 or 30 microg sufentanil and 14 and 20 h after 0.1 or 0.3 mg morphine, respectively. This recovery profile can be explained by the spinal pharmacokinetics of both opioids. Intrathecal opioids decrease bladder function by causing dose-dependent suppression of detrusor contractility and decreased sensation of urge. Recovery of normal lower urinary tract function is significantly faster after intrathecal sufentanil than after morphine, and the recovery time is clearly dose dependent.
Current Urology Reports, 2001
The Journal of Urology
Increasing urethral occlusion pressures were created with an artificial sphincter in bladder-uret... more Increasing urethral occlusion pressures were created with an artificial sphincter in bladder-urethra specimens of adult female pigs. Antegrade urethral perfusion pressures, at 19.5 ml./min. through a flexible F8 urethral catheter with an F12 outflow sleeve of tube-foil, closely approximated the associated intravesical pressures at which leakage from the noncatheterized urethra starts. With this new technique, leakage pressure and thus urethral competence can be measured accurately and continuously, almost independently from bladder pressure and pelvic floor movement.
The Journal of Urology
Increasing urethral occlusion pressures were created with an artificial sphincter in fresh bladde... more Increasing urethral occlusion pressures were created with an artificial sphincter in fresh bladder-urethra specimens of adult pigs. Detrusor leakage pressures remained about 25 per cent below the associated sphincter cuff pressures. The same relation was found when, during abrupt variations of cuff pressure, the detrusor leakage pressures were measured with antegrade urethral perfusion pressure measurement through a new sleeve catheter. Side-hole perfusion pressure measurements showed 100 per cent transmission of abrupt variations of cuff pressures to the inner urethral wall. No rotational differences could be detected. From the results it has been concluded that a probable pressure loss of about 25 per cent must be taken into account when converting artificial sphincter pressures into bladder pressures at which leakage will occur.
The Journal of Urology
In pigs, the effectiveness of ureteral peristaltic fluid discharge from the ureterovesical juncti... more In pigs, the effectiveness of ureteral peristaltic fluid discharge from the ureterovesical junction at high intravesical pressures was evaluated by ureterovesical perfusion pressure (UVPP) measurements and continuous endoscopic observation of the ureteral orifice during cystometry. Basal UVPPs either remained low, or were elevated but then intermittently could be reduced to near pre-bladder-filling levels at the end of the peristaltic pressure waves during which fluid was discharged from the ureteral orifice. Reductions of elevated basal UVPP correlated with the volumes of the associated discharged fluid boluses and with the perfusion times until such decreased basal UVPP again reached the elevated level it had before the peristaltic pressure waves. Even an elevated juxtavesical basal ureteral pressure which was already well below high intravesical pressure could be further reduced to near normal level after a ureteral peristaltic contraction which was accompanied by fluid discharge from the ureteral orifice. The clinical implications of these findings are discussed.
The Journal of Urology
In pigs, ureterovesical pressure profiles were analyzed by combined prevesical perfusion pressure... more In pigs, ureterovesical pressure profiles were analyzed by combined prevesical perfusion pressure measurement and microsensor pressure profilometry of the ureterovesical junction, which showed comparable and reproducible fast and slow pressure waves. Cystoscopy revealed that the fast pressure waves were associated with fluid spurts from the ureteral orifice and wrinkling of bladder mucosa over the ureterovesical junction. During slow pressure waves only initial decreases in outflow from the orifice may occur. After dissection of the detrusor muscle at the UVJ only fast pressure waves were recorded. At similar pressure measurements on an inactivated ureter segment which was obliquely passed through the bladder wall only slow pressure waves could be detected. It is concluded that the fast pressure waves of the ureterovesical pressure profile represent peristaltic activity which is generated at the ureterovesical junction and by which fluid may be discharged into the bladder. The slow pressure waves of the pressure profile reflect impairment of flow through the ureterovesical junction by detrusor activity.
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Papers by Ger van Venrooij