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Biomedical subjects

J C Djurhuus

Publications and source records attributed to J C Djurhuus.

At least 19 recordsLinked to original sources
PubMed2001

Renal function outcome in unilateral hydronephrosis in newborn pigs. II. Function and volume of contralateral kidneys.

PURPOSE: We evaluated the compensatory response of contralateral kidney growth and function in pigs with unilateral hydronephrosis. MATERIALS AND METHODS: Unilateral partial ureteral obstruction causing severe hydronephrosis was induced at age 2 days in 12 piglets, while 10 underwent sham operation. At ages 4, 12 and 24 weeks single kidney function was assessed using 99mtechnetium diethylenetriaminepentaacetic acid differential uptake on renography combined with the glomerular filtration rate estimated from the plasma clearance of 99mtechnetium diethylenetriaminepentaacetic acid. Kidney size was measured in parallel by magnetic resonance imaging. RESULTS: At 4 weeks the glomerular filtration rate and volume of the contralateral kidneys did not differ from those in controls, although obstructed kidney function was significantly decreased. At 12 weeks the mean glomerular filtration rate plus or minus standard error of mean of the contralateral kidneys significantly increased to 1.60 +/- 0.11 versus 1.33 +/- 0.11 ml. per minute per kg. (p <0. 05), whereas kidney volume did not differ from that in sham operated controls. At 24 weeks the glomerular filtration rate and volume of the contralateral kidneys did not differ from those in controls. Glomerular filtration rate and volume of the contralateral kidneys did not correlate at 4 weeks but they correlated at 12 and 24 weeks (r = 0.94 and 0.89, respectively). CONCLUSIONS: Initially kidneys contralateral to obstructed kidneys with decreased function had no increased growth or function. Furthermore, function and volume of the contralateral kidneys were not associated at the early age. Thus, the results of our study imply that determining the size (growth) or function of the contralateral kidney at an early age does not predict function decrease in a partially obstructed kidney in this pig model.

Animals↗
PubMed2000

[Urinary incontinence and pregnancy, vaginal childbirth and obstetric interventions].

The aim was to examine the association between pregnancy, vaginal childbirth (VC) and obstetric techniques, and the prevalence of urinary incontinence (UI). A cross-sectional survey enrolled a random population sample of 6240 women aged 20-59 years, who were mailed a self-administered questionnaire on UI and, among other things, experience of VC and obstetric intervention. More than 75% responded. The present analysis includes 4345 women. Multivariate UI prevalence odds ratios were increased in relation to UI during pregnancy, UI following immediately after a VC, and age 30 or more at the second VC. No multivariate association was found in relation to forceps delivery or vacuum extraction delivery, episiotomy or perineal suturing. In conclusions, not only the process of childbirth itself but also processes during pregnancy seem to be strongly associated with prevalent UI. Perineal suturing may be associated with prevalent UI, whereas other obstetric techniques inspected do not seem to be so.

Adult↗
PubMed2000

In vivo measurements of relaxivities in the rat kidney cortex.

The aim of this study was to implement a novel noninvasive method to derive the in vivo T1 relaxivity (R1) and T2 relaxivity (R2) in the rat kidney cortex. A two-compartment gadolinium diethylene triamine pentaacetic acid (Gd-DTPA) distribution model was established to estimate the bolus and infusion dosages of Gd-DTPA necessary for obtaining the required steady-state concentration levels. After a single bolus injection of (99m)Tc-DTPA, several blood samples were collected. Based on considerations from the applied two-compartment model, a steady-state concentration was predicted approximately 5-10 minutes after the bolus injection. The plasma concentration levels of Gd-DTPA were measured by simultaneous injection of (99m)Tc-DTPA. Three regions in the cortex (upper, central, and lower) of both rat kidneys were used. A statistical evaluation resulted in the following in vivo relaxivities found at 7 T: R1 = 1.04 +/- 0.08 mM(-1)s(-1) and R2 = 10.78 +/- 0.83 mM(-1)s(-1). Using a 95% confidence interval, no intracortical differences were detected. The relaxivities R1 and R2 calculated in the intact rat kidney cortex were distinctly different from relaxivities found in human plasma: (22 degrees C) 4.42 +/- 0.07 mM(-1)s(-1) (r2> 0.98) and R2 = 5.75 +/- 0.17 mM(-1)s(-1) (r2> 0.98), respectively. The measurements showed a marked difference between in vitro and in vivo relaxivities. Comparison of the distribution rates in pig, human, and rats shows a distinct proportionality between size and renal function.

Animals↗
PubMed2000

Cystometry techniques in female infants and children.

Cystometry is increasingly used in children, being an important diagnostic tool for congenital and acquired malformations such as neurogenic bladder, vesicoureteric reflux, urinary tract infection, urge syndrome, nocturnal enuresis, urinary incontinence and anorectal malformations. During cystometry bladder storage and voiding function can be evaluated. Carefully conducted urodynamic studies provide an insight into the pathophysiologic mechanisms involved in voiding dysfunctions that cannot be obtained by any other diagnostic technique. A variety of methods are available, the most sophisticated being filling and voiding cystometry with flowmetry and electromyography (EMG) under fluoroscopy, i.e. videocystometry. A detailed home recording of the frequency and volume of micturition can provide important clues as to the underlying bladder dysfunction, and can significantly aid in the choice of appropriate investigative techniques, as well as in the interpretation of subsequent urodynamic findings. It must be realized that urodynamic studies are invasive procedures and that artifacts may occur and influence the correct interpretation of the results. Infants and children have a different spectrum of bladder dysfunctions from adults and are generally much less cooperative during a urodynamic study. Therefore, cystometric techniques must be significantly modified. This article reviews cystometry techniques and their application in female infants and children. Cystometry/flow/EMG studies with or without fluoroscopy, ambulatory urodynamics and telemetric urodynamic measurement and their application are outlined.

Adult↗
PubMed2000

A 14-year follow-up of conservative treatment for vesico-ureteric reflux.

OBJECTIVE: To determine renal function in patients with vesico-ureteric reflux (VUR) during 14 years of conservative treatment (no surgery). PATIENTS AND METHODS: Sixty patients with VUR were consecutively included between 1981 and 1982. The degree of VUR was determined by conventional voiding cysto-uretherography (VCUG) after 3 months of prophylactic antibiotics. The VUR was grade I-IV, with grades III and IV characterized as high-grade VUR. In all patients, any urinary tract infections and bladder-urethral dysfunction were treated. Renal function and reflux were monitored by renal and bladder scintigraphy using 123I-hippuran and the glomerular filtration rate (GFR) was determined using the plasma clearance of 51Cr-ethylaminediamine tetra-acetic acid. RESULTS: Of the 60 patients who entered the study, 51 were followed for a mean of 13.7 years; nine patients were lost to follow-up. None of the patients underwent antireflux surgery. All patients were in good health and normotensive (except two with borderline hypertension). Of the 51 patients 21 had low-grade, 21 unilateral high-grade and nine bilateral high-grade reflux. In those with low-grade reflux both the mean renal split function on the most refluxing kidney and the GFR remained stable during the whole monitoring period. Eighteen patients who had a persistent reduction in renal split function or initially had had a significantly reduced functional share to the most refluxing kidney had their GFR re-assessed in adolescence. However, the body surface-corrected GFR remained constant. Total GFR and single kidney GFR increased significantly. CONCLUSION: A conservative treatment regimen in patients with VUR can ensure stable kidney function, although kidneys with a lower renal function at referral seem to have an impaired functional growth potential.

Adolescent↗
PubMed2000

Evaluation of renal function in normal and hydronephrotic kidneys in rats using gadolinium diethylenetetramine-pentaacetic acid enhanced dynamic magnetic resonance imaging.

PURPOSE: Magnetic resonance imaging (MRI) is becoming established as a modality complementary to computerized tomography and ultrasound for evaluating kidney function. The evaluation of renal function during ureteral obstruction may be improved by contrast enhanced MRI. We evaluated dynamic changes in relative signal intensity in normal and hydronephrotic rat kidneys after intravenous injection of gadolinium (Gd) diethylenetetramine-pentaacetic acid (DTPA). MATERIALS AND METHODS: Using Gd-DTPA enhanced dynamic MRI we evaluated 35, 1-year-old rats, including 10 with partial and complete unilateral ureteral obstruction, respectively, and 15 with sham operated nonobstructed kidneys. Partial obstruction was created in 2-day-old rats by embedding the left ureter into the psoas muscle. Complete obstruction was created 10 days before MRI by placing a ligature around the upper third of the left ureter. MRI was performed before and 0.1 to 60 minutes after and intravenous injection of Gd-DTPA. We calculated relative signal intensity per time interval in the renal cortex, medulla and pelvis. RESULTS: Dynamic relative signal intensity patterns differed significantly among normal, and partially and completely obstructed kidneys. In normal kidneys signal intensity changes were divided into 3 phases after Gd-DTPA administration. During phase 1 rapid parenchymal uptake of Gd-DTPA within the initial minute after injection produced a rapid signal intensity decrease in the cortex, which achieved a minimum of 28% of pre-injection intensity. During phase 2 signal intensity decreased in the medulla and pelvis to a minimum of 18% and 22%, respectively, of pre-injection intensity within 5 minutes. During phase 3 significant relative signal intensity recovery began in the cortex at 7 minutes, and in the medulla and pelvis at 10 to 15 minutes, and lasted 30 to 60 minutes. In partially obstructed kidneys the 3 phases were significantly slower than in controls. In completely obstructed kidneys only phase 1 occurred within 60 minutes. CONCLUSIONS: Gd-DTPA enhanced dynamic MRI provides useful information for distinguishing obstructed from nonobstructed and partially from completely obstructed kidneys.

Animals↗
PubMed2000

Analysis of bladder related nerve cuff electrode recordings from preganglionic pelvic nerve and sacral roots in pigs.

PURPOSE: Electrical stimulation of appropriate lower urinary tract (LUT) nerves may be used in bladder dysfunction to achieve continence and abolish hyper-reflexic detrusor contractions. It can also be used for consequent emptying of the bladder. To control the time course of the described functional phases, knowledge of bladder sensory information is needed. We investigated if the latter could be extracted from the LUT nerve activity. MATERIALS AND METHODS: In acute experiments using 10 pigs, tripolar cuff electrodes were placed unilaterally around the pelvic nerve and the S3 and S2 roots. The cuff electrode signals, filling rate and the bladder and rectal pressures were recorded during slow and fast bladder fillings/emptyings. RESULTS: Two pigs were excluded from the analysis because of no observed changes in the nerve signals in one animal, and because of electrical noise problems in the other animal. Fast bladder pressure increases resulted in a sudden pelvic nerve signal rise in 6 out of 7 pigs (3 out of 6 for the S3 nerve signal). Slow bladder pressure increase was reflected in the recorded nerve activity only in 3 out of 8 and in 3 out of 7 pigs for the pelvic and S3 cuff signals respectively. In 2 animals small spontaneous bladder contractions were clearly reflected in the pelvic nerve signal (contractions were observed only in 3 pigs). Except in one pig, there were no slow/fast bladder filling responses recorded in the S2 roots. It is shown that the recorded responses were afferent. CONCLUSIONS: Cuff electrodes can be used to record bladder afferent information from the pelvic nerve and the sacral root S3 in pig. Pelvic nerve recordings were more selective than the sacral root recordings. Nerve activity increases were more distinct and repeatable during rapid bladder pressure changes and small spontaneous bladder contractions than during slow bladder fillings.

Action Potentials↗
PubMed2000

Renal functional outcome in unilateral hydronephrosis in newborn pigs.

PURPOSE: We followed the course of neonatally induced, partial unilateral ureteral obstruction in pigs and established whether early function or morphological evaluation of the hydronephrotic kidney is predictive of outcome. MATERIALS AND METHODS: In 25 piglets unilateral partial ureteropelvic obstruction was induced 2 days after birth, while 11 underwent sham operation. Only obstructed kidneys with significant dilatation at 4 weeks were included for further study. Renal function was assessed on renography using (99m)technetium-diaminetriaminepentaacetic acid differential uptake. According to the plasma clearance of (99m)technetium-diaminetriaminepentaacetic acid the glomerular filtration rate was determined at ages 4, 12 and 24 weeks. Kidney morphology was studied in parallel by magnetic resonance imaging. RESULTS: A total of 12 obstructed kidneys with grade 3 or 4 hydronephrosis fulfilled study inclusion criteria. Of 6 kidneys with a functional share of 40% or greater at age 4 weeks 2 deteriorated to less than 40% at 24 weeks, while 4 of 6 with a share of less than 40% at age 4 weeks improved to greater than 40% at 24 weeks. The single kidney glomerular filtration rate at 4 weeks did not correlate with that at 12 or 24 weeks but the rate at 12 weeks correlated with that at 24 weeks (r2 = 0.8140, p <0.001). Neither relative volume of the obstructed kidney nor length of the contralateral nonobstructed kidney correlated with functional share of the obstructed kidney at any age. CONCLUSIONS: Early evaluation of kidney function or volume, or contralateral kidney length did not predict the outcome of neonatally induced unilateral hydronephrosis in pigs.

Age Factors↗
PubMed1999

Pad testing in incontinent women: a review.

This article reviews the literature on pad-weighing tests used for objectifying and quantifying incontinence in urinary incontinent women. The patients wear pads weighed before and after the test period. A weight gain is taken as a measure of the amount of urine loss. The tests are in principle of two different types: short-term office tests and long-term home tests, and measure different aspects of urinary control and dysfunction. Both have an inherent large intra- and interindividual variability. Pad weight gains obtained from patients referred for incontinence and those from self-reported continent controls overlap to a certain degree, and it is not possible to identify distinct numerical cut-off values separating continence from incontinence. This suggests that incontinence is a complex condition in which the amount of leakage, other sources of weight gain, and differences in the individual patients' personal characteristics influence the identification and quantification of the problem. In spite of the shortcomings the pad tests remain a valuable tool for both the clinician and the researcher. The home pad tests are superior to the office tests in terms of authenticity, and should be performed with a concomitant systematic registration of the participant's voidings, fluid intake and episodes of incontinence.

Bias↗
PubMed1999

Obstructive nephropathy: an update of the experimental research.

Ureteral obstruction (UO) is one of the most common problems confronting the urologist. Although large amounts of animal and clinical research have been done, the pathophysiologic mechanisms accompanying UO are not fully elucidated. Most of our knowledge on UO has been derived from experimental studies in a variety of animal models. Both antenatal and postnatal UO models have been developed mainly by ligation of the ureter or by burying the ureter into the psoas muscle. Most experimental studies have focused on short-term complete ureteral obstruction. The long-term effects of partial ureteral obstruction have been less intensively studied. It is now clear that obstructive nephropathy is not a simple result of mechanical impairment to urine flow but a complex syndrome resulting in alterations of both glomerular hemodynamics and tubular function caused by the interaction of a variety of vasoactive factors and cytokines that are activated in response to UO. Leukocyte infiltration appears to play an important role in obstructive nephropathy suggesting that UO also has an immunological component. Growth factors such as platelet-derived growth factor, transforming growth factor-beta, epidermal growth factor and insulin-like growth factor I may all play a role in the development and progression of fibrotic and sclerotic changes in the obstructed kidney. At present, the selection of patients with congenital hydronephrosis for operative treatment is controversial. Studies in animals and patients have shown that partial unilateral UO does not always cause a loss of renal function or progression in urinary tract dilation during long-term follow-up. The implications of UO continue to raise many questions and further work is necessary to achieve a better understanding of the pathogenesis in obstructive nephropathy.

Animals↗
PubMed1999

Contralateral compensatory kidney growth in rats with partial unilateral ureteral obstruction monitored by magnetic resonance imaging.

PURPOSE: We studied dynamic changes in total volume and renal vein blood flow in the kidneys contralateral to partial ureteral obstruction induced in newborn rats. MATERIALS AND METHODS: Using magnetic resonance imaging we investigated changes in total kidney volume and renal vein blood flow in 20 rats with mild and 18 with severe partial ureteral obstruction that was induced on the left side 2 days after birth. A total of 15 sham operated control rats were also studied. Total kidney volume and renal vein blood flow were monitored sequentially every 2 to 6 weeks for a total of 24 weeks. Renal parenchymal volume measured in vivo by magnetic resonance imaging was compared with that measured in vitro at week 24. RESULTS: Total volume and renal vein blood flow increased significantly in contralateral nonobstructed kidneys from week 14 and thereafter in rats with severe partial unilateral ureteral obstruction. At week 24 volume had increased by 22% and blood flow had increased by 25%. Volume and flow did not increase significantly in contralateral nonobstructed kidneys in rats with mild partial unilateral ureteral obstruction (p = 0.09). Before changes occurred in volume and blood flow in the contralateral nonobstructed kidneys, renal vein blood flow had decreased significantly from week 8 and thereafter in severely obstructed kidneys. In rats with mild partial unilateral ureteral obstruction renal vein blood flow decreased significantly in obstructed kidneys from week 18 and thereafter. Good correlation was noted between MRI in vivo and in vitro kidney volume measurements (r = 0.972, p <0.001). CONCLUSIONS: A significant increase in total volume and renal vein blood flow in contralateral nonobstructed kidneys did not develop immediately after the onset of detectable functional deterioration in partially obstructed kidneys. Therefore, caution should be used when incorporating compensatory growth into surgical decision making.

Animals↗
PubMed1999

Nocturia and polyuria in men referred with lower urinary tract symptoms, assessed using a 7-day frequency-volume chart.

OBJECTIVES: To investigate if a 7-day frequency-volume (FV) chart could identify nocturia on a polyuric basis in patients with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: The study included 23 patients (mean age 62.8 years, range 42-78) with LUTS who were referred for the evaluation of potential BPH and 11 men (control subjects, mean age 63.3 years, range 58-69); all completed a 7-day FV chart investigation as outpatients. RESULTS: Nocturia was associated with nocturnal polyuria in 10 of 23 patients with LUTS; these 10 patients had a diminished diurnal variation of urine production, whereas 13 patients had a diurnal variation in urine production comparable with that in controls with no nocturia. The degree of nocturia correlated positively with nocturnal urine production but showed no relationship with sleep duration. The nocturnal polyuria in these patients was associated with a higher 24-h urine production and seemed at least partly to be caused by a higher fluid intake during daytime. CONCLUSION: Nocturia on a polyuric basis can be detected by using a FV chart. In these patients, a 3-day FV chart would be sufficient to detect nocturia on a polyuric basis and seems therefore to be a valuable tool in evaluating patients with LUTS referred for potential BPH.

Adult↗
PubMed1999

Fluid deprivation in enuresis--effect on urine output and plasma arginine vasopressin.

Desmopressin responders tend to have a large volume of urine production at night, in contrast to desmopressin refractory patients who often produce normal volumes of urine. Controls and adolescent/adult primary monosymptomatic nocturnal enuretics were included in a study measuring urine volume and plasma vasopressin levels before and during a 24-hour water deprivation test. The results indicate a significantly higher urine production in desmopressin responders when compared with controls and non-responders. Before fluid deprivation, only the nocturnal polyuric patients showed a urine osmolality significantly lower than that of controls and desmopressin non-responders. A significant decrease in the clearance of osmols was evident in the desmopressin refractory group from day to night. All three groups showed a significant increase in plasma vasopressin during fluid deprivation, with polyuric, desmopressin-responding patients showing a lower increase that the non-responders and controls. Plasma vasopressin levels were normal in adolescent and adult enuretics regardless of their response to desmopressin. Moreover, response to fluid deprivation in both polyuric and enuretic patients resulted in a significant decrease in urine output from the first to the second night.

Administration, Intranasal↗
PubMed1999

Prevalent urinary incontinence as a correlate of pregnancy, vaginal childbirth, and obstetric techniques.

OBJECTIVES: This study examined the association between pregnancy, vaginal childbirth and obstetric techniques, and the prevalence of urinary incontinence among adult women aged 20 to 59 years. METHODS: A cross-sectional survey enrolled a random sample of 6240 women aged 20 to 59 years who were mailed a self-administered questionnaire focusing on urinary incontinence and other health variables. More than 75% of the women responded. The present analysis includes 4345 women who were not pregnant and did not experience a vaginal childbirth during 1994. RESULTS: Multivariate prevalence odds ratios showed increases in relation to urinary incontinence during pregnancy, urinary incontinence immediately after a vaginal childbirth, and age of 30 years or more at the second vaginal childbirth. No multivariate associations were found for forceps delivery or vacuum extraction delivery, episiotomy, or perineal suturing. CONCLUSION: Not only the process of childbirth itself but also processes during pregnancy seem to be strongly associated with prevalent urinary incontinence. Perineal suturing may be associated with prevalent urinary incontinence, whereas other obstetric techniques inspected do not seem to be so.

Adult↗