Evaluation of back scatter interferometry, a method for detecting protein binding in solution.

Back Scatter Interferometry (BSI) has been proposed to be a highly sensitive and versatile refractive index sensor usable for analytical detection of biomarker and protein interactions in solution. However the existing literature on BSI lacks a physical explanation of why protein interactions in general should contribute to the BSI signal. We have established a BSI system to investigate this subject in further detail. We contribute with a thorough analysis of the robustness of the sensor including unwanted contributions to the interferometric signal caused by temperature variation and dissolved gasses. We report a limit of the effective minimum detectability of refractive index at the 10(-7) level. Long term stability was examined by simultaneously monitoring the temperature inside the capillary revealing an average drift of 2.0 × 10(-7) per hour. Finally we show that measurements on protein A incubated with immunoglobulin G do not result in a signal that can be attributed to binding affinities as otherwise claimed in literature.

An elegant technique for ex vivo imaging in experimental research-Optical coherence tomography (OCT).

Optical coherence tomography (OCT) is an elegant technology for imaging of tissues and organs and has been established for clinical use for around a decade. Thus, it is used in vivo but can also serve as a valuable ex vivo imaging tool in experimental research. Here, a brief overview is given with a focus on an ex vivo application of OCT. Image and video examples of freshly obtained murine lungs are included. The main advantage of OCT for ex vivo analysis is the non-contact, non-invasive, and non-destructive fast acquisition of a three-dimensional data set with micrometer-resolution.

International Children's Continence Society's recommendations for therapeutic intervention in congenital neuropathic bladder and bowel dysfunction in children.

PURPOSE: We present a consensus view of members of the International Children's Continence Society on the therapeutic intervention in congenital neuropatic bladder and bowel dysfunction in children. MATERIAL AND METHODS: Discussions were held by a group of pediatric urologists and gastroenterologists appointed by the board. The following draft review document was open to all the ICCS members via the ICCS web site. Feedback was considered by the core authors and by agreement, amendments were made as necessary. The final document is not a systematic literature review. It includes relevant research when available as well as expert opinion on the current understanding of therapeutic intervention in congenital neuropatic bladder and bowel dysfunction in children. RESULTS: Guidelines on pharmalogical and surgical intervention are presented. First the multiple modalities for intervention that do not involve surgical reconstruction are summarized concerning pharmacological agents, medical devices, and neuromodulation. The non-surgical intervention is promoted before undertaking major surgery. Indicators for non-surgical treatments depend on issues related to intravesical pressure, upper urinary tract status, prevalence of urinary tract infections, and the degree of incontinence. The optimal age for treatment of incontinence is also addressed. This is followed by a survey of specific treatments such as anticholinergics, botulinum-A toxin, antibiotics, and catheters. Neuromodulation of the bladder via intravesical electrical stimulation, sacral nerve stimulation, transcutaneous stimulation, and biofeedback is scrutinized. Then follows surgical intervention, which should be tailored to each individual, based on careful consideration of urodynamic findings, medical history, age, and presence of other disability. Treatments mentioned are: urethral dilation, vesicostomy, bladder, augmentation, fascial sling, artificial urinary sphincters, and bladder neck reconstruction and are summarized with regards to success rates and complications. Finally, the treatment on neuropathic bowel dysfunction with rectal suppositories irrigation and transrectal stimulation are scrutinized.

Effect of remote ischemic conditioning on dendritic cell number in blood after renal transplantation--flow cytometry in a porcine model.

Delayed graft function after transplantation increases the risk of rejection. Remote ischemic conditioning (rIC) consists of repetitive, brief, non-damaging periods of ischemia in a limb. For reasons not fully understood, rIC protects the target organ against subsequent ischemia-reperfusion injury. Because ischemic endothelium attracts dendritic cells (DCs), we hypothesised that rIC protects the organ by "trapping" circulating DCs in the limb exposed to rIC. With fewer DCs thus available to infiltrate the graft, a strong T-cell mediated immune response toward the graft is less likely. To test this hypothesis, we measured the number of circulating DCs in a porcine model of renal transplantation with and without rIC. Brain death was induced in eight 65-kg donor pigs. After 22 h of cold ischemia, the kidneys were transplanted into sixteen 15-kg recipient pigs. The recipients were randomised to either non-rIC or rIC before reperfusion of the graft and observed 10 h after reperfusion. The number of DCs was determined by flow cytometry. DCs were identified on the basis of forward- and side-scatter characteristics of CD14-negative mononuclear cells with expression of CD172a. Dendritic cells were subclassified as either plasmacytoid (pDCs) (CD172a(dim), CD4(+), CD14(-)) or conventional (cDCs) (CD172a(high), CD4(-), CD14(-)). Remote ischemic conditioning did not affect the number of circulating cDCs or pDCs within the 10h after transplantation studied. Regardless of rIC, the number of pDCs decreased after graft reperfusion and then returned to baseline levels. In contrast, the number of circulating cDCs increased after reperfusion and later returned to baseline levels.

Macular morphology and visual acuity after macular hole surgery with or without internal limiting membrane peeling.

AIM: To examine postoperative macular morphology and visual outcome after 12 months in relation to internal limiting membrane (ILM) peeling versus no peeling, indocyanine green (ICG) staining and re-operation in eyes that achieved macular hole closure after surgery. METHODS: Seventy-four eyes with closed stage 2 or 3 macular holes were recruited from a randomised clinical trial comparing: (1) vitrectomy without ILM peeling; (2) vitrectomy with 0.05% isotonic ICG-assisted ILM peeling; and (3) vitrectomy with 0.15% trypan blue-assisted ILM peeling. Contrast-enhanced Stratus optical coherence tomography was used to assess central foveal thickness, central photoreceptor layer thickness (CPRT), central photoreceptor layer discontinuity (PRD) and relative reflectivity of the outer nuclear layer. Outcomes were correlated with best corrected visual acuity (BCVA) 12 months after surgery. RESULTS: BCVA was correlated with CPRT and PRD. Regression analysis and receiver operating characteristics curve analysis showed that CPRT >33 microm (OR 12.5) and PRD <177 microm (OR 9.86) were highly predictive for regaining reading vision (> or =69 Early Treatment of Diabetic Retinopathy Study letters) 12 months after surgery. No significant difference was found in postoperative macular morphology between subgroups. CONCLUSIONS: Poor vision after 12 months despite macular hole closure was associated with attenuation and disruption of the foveolar photoreceptor matrix. The extent of attenuation and disruption was independent of peeling and staining. TRIAL REGISTRATION NUMBER: NCT00302328.

Detection of local metabolic changes after progressive and stepwise reduction of renal blood flow in pigs.

PURPOSE: Vascular complications after renal transplantation causing initially only partial renal ischemia can be difficult to discover in time to save the kidney. Our aims were to design an animal model allowing progressive and stepwise reduction of the arterial renal blood flow (RBF) and to investigate whether microdialysis could detect the subsequent metabolic changes. MATERIALS AND METHODS: Eight pigs were used. Two microdialysis catheters were placed, one in the lateral renal cortex, the other just outside the renal capsule. Baseline measurements were obtained at steady state. Five injections of 100 mu-polyvinyl alcohol (PVA) particles were administered once every hour through an angiographic catheter placed in the renal artery to cause the RBF to gradually decline. The glomerular filtration rate (GFR) was estimated by (51)Cr-EDTA. RESULTS: One diseased animal was excluded. GFR, RBF, and all metabolites measured by microdialysis remained stable during 2 hours of baseline measurements (ANOVA; P > .05). Within 30 minutes, the first injection of PVA particles caused a reduction of RBF to 40 +/- 13% of the baseline flow (t test; P < .001 vs baseline). Significant changes in cortical lactate and glutamate as well as extracapsular glutamate were also seen, at indicating ischemia (n = 7). Cortical glucose changed 60 minutes after baseline (n = 7). CONCLUSION: Acute, stepwise renal blood flow reduction was achieved by injection of PVA particles. An early warning of developing ischemia is provided by microdialysis. This technique could be clinically valuable because it could be instrumental in improving survival of transplanted kidneys suffering from postoperative ischemia.

Evaluation of complete and partially obstructed kidneys using Gd-DTPA enhanced dynamic MRI in adolescent swine.

PURPOSE: Aim of this study was to evaluate the dynamic changes in renal relative signal intensity (RSI) following the administration of Gd-DTPA in adolescent pigs with complete and partial unilateral ureteric obstruction. METHODS: Pigs were divided into 3 groups: partial and complete unilateral ureteric obstruction and controls. Complete unilateral ureteric obstruction (CUUO) was created by ligating the left ureter, whereas partial unilateral ureteric obstruction (PUUO) was created in pigs of 2 weeks of age by embedding the left ureter into the psoas muscle. Dynamic MRI was performed before and at 0 - 60 min after an intravenous bolus injection of Gd-DTPA. Mean RSI of the renal cortex, medulla and pelvis was measured and interpreted as an indirect measure of the renal function. In addition, renography was performed, and renal morphology was examined IN VITRO. RESULTS: Three phases of RSI were identified. The dynamic RSI patterns differed markedly between obstructed and control kidneys. In PUUO kidneys, Phase 1 of the mean RSI of the cortex and medulla demonstrated a decreased amplitude and prolonged duration, whereas in Phase 2 the mean RSI of the pelvis was increased. In acute CUUO kidneys, the mean RSI patterns were similar to those of controls, except for a significant increase of the pelvic mean RSI. CONCLUSIONS: Gd-DTPA enhanced dynamic MRI allowed a characterization and differentiation of renal function and morphology of normal and obstructed kidneys, and secondly, provided potentially important information on renal concentrative and filtration availability.

Normative data of outer photoreceptor layer thickness obtained by software image enhancing based on Stratus optical coherence tomography images.

AIM: To present normative data of outer photoreceptor layer thickness obtained by a new semiautomatic image analysis algorithm operating on contrast-enhanced optical coherence tomography (OCT) images. METHODS: Eight Stratus OCT3 scans from identical retinal locations from 25 normal eyes were registered and combined to form a contrast-enhanced average image. Utilising the vertical intensity gradients of the enhanced OCT images to demarcate retinal layers, thickness measurements of the outer photoreceptor- and retinal pigment epithelium layer (RPE-OS(complex)) were obtained. Additionally backscattered light within the outer nuclear layer (ONL) in the fovea was registered and compared with backscattered light within the ONL in the peripheral part of the macula (I(ratio)-ONL). RESULTS: The mean RPE-OS(complex) thickness in the foveal centre was 77.2 microm (SD = 3.95). The RPE-OS(complex) thickness in the superior macula 0.5-3 mm of the centre was significantly increased as compared with the corresponding inferior retina. In healthy subjects, the I(ratio)-ONL was 1.06. CONCLUSIONS: Contrast-enhanced OCT images enable quantification of outer photoreceptor layer thickness, and normative values may help understanding better the relationship between functional outcome and photoreceptor morphology in retinal diseases.

Enhanced optical coherence tomography imaging by multiple scan averaging.

AIMS: To describe a method for computerised alignment and averaging of sequences in optical coherence tomography (OCT) B-scans and to present selected clinical observations based on the resulting improvement in retinal imaging. METHODS: A methodological study and retrospective investigation of selected cases. Five human subjects were included, one healthy subject, two patients with central serous chorioretinopathy, one patient with branch retinal vein occlusion, and one patient with cilioretinal artery pseudo-occlusion. Based on computerised alignment of sets of B-scans obtained at identical retinal locations, average OCT images were produced and displayed in false colour or grayscale. These enhanced tomograms were compared with other morphological and functional characteristics. RESULTS: Improved retinal imaging enabled assignment of the OCT image to retinal anatomy particularly at the outer layer of the photoreceptors and the retinal pigment epithelium, both in the healthy eye and in pathology. Identification of both post-oedematous structural disorganisation as well as post-ischaemic attenuation of the inner retina was superior to standard OCT images. CONCLUSIONS: Averaging of multiple OCT B-scans enhances the quality of retinal imaging sufficiently to reveal new details of retinal pathophysiology. Using the technique on OCT3 scans enables visualisation of details comparable with the results obtained using ultra high resolution OCT.

Robotically assisted retroperitoneoscopic heminephrectomy in children: initial clinical results.

OBJECTIVE: To investigate the feasibility of robotically assisted retroperitoneoscopic upper pole heminephrectomy with the Da Vinci Surgical System. PATIENTS AND METHODS: Fourteen girls (median age 4.9 years, range 0.5-20.2) underwent upper pole heminephrectomy using the retroperitoneal approach with the Da Vinci Surgical System. Prior to all procedures a ureteric catheter was placed. Using a modified access to the retroperitoneum the ureter to the upper pole and the vessels were dissected and ligated. The upper pole was removed by diathermy or ultrasonic scissors. RESULTS: The median operative time was 176 min (range 120-360 min). In two patients, the procedure was converted to an open operation; in one case due to lack of progress, and in the other due to bleeding which could not be handled with the robotically assisted instruments. One patient had the ureteric stump removed due to recurrent infections. In all other patients the peri- and postoperative period was uneventful. CONCLUSION: The robotically assisted system is an excellent tool for minimally invasive surgery in the retroperitoneum, such as pyeloplasty, with its advantages of wrist-like movements of the instruments, magnified three-dimensional view, tremor control and improved ergonomics for the surgeon. Further development of the instruments is required before the resection of a non-functioning upper pole can be included in the spectrum of indications.

Twenty-four-hour ambulatory urodynamics in healthy young men.

OBJECTIVE: To describe normal natural fill urodynamics in young men during normal and increased fluid intake. MATERIAL AND METHODS: Thirty healthy males aged 21-32 years volunteered for an ambulatory urodynamic 24 h investigation with a suprapubic catheter. The recorded micturition data were: frequency (f), voided volume (VV), voiding time, maximal flow rate (Qmax) and time to Qmax. The number of sensed and not-sensed bladder contractions, duration and time in relation to voiding were also recorded. During the recording day subjects were randomized to normal (30 ml/kg body weight per day) or larger (60 ml/kg body weight per day) fluid intake. RESULTS: As expected there was a larger urine production and an increased voiding frequency in the fluid-loaded group (p<0.0001). The detrusor pressure (Pdet) Qmax was significantly higher in the fluid-loaded group (73 cmH2O, range 57-94) than in the normal fluid intake group (60 cmH2O, range 45-86) (p=0.003). No other urodynamic data differed significantly between the two groups. When comparing the ambulatory urodynamic data with previously obtained home flowmetry recordings from the same volunteers differences were only found in voiding frequency. The majority of participants had detrusor contractions, felt and unfelt, during the filling phase. Three types of detrusor activity during voiding phase could be described: type 1, with one micturition contraction, type 2, with several small contractions before micturition, and type 3, with large prolonged contractions leading to micturition. CONCLUSIONS: Ambulatory urodynamics in normal young men showed a large interindividual variation. Bladder contractions during filling were frequently recorded, and premicturition contractions were consistently found. The data found in this study were similar to previous home flow recordings in the same group.

Computer assisted pyeloplasty in children: the retroperitoneal approach.

PURPOSE: We describe the first series of computer assisted retroperitoneoscopic pyeloplasty in children using the Da Vinci Surgical System (Intuitive Surgical, Inc., Mountainview, California) with regard to setup, method, operation time, complications and preliminary outcome. The small space in the retroperitoneum of children and larger instruments of the computer assisted surgical system make modification of the retroperitoneal access necessary. MATERIALS AND METHODS: In 13 children with a median age of 6.7 years (range 3.5 to 16.2) and ureteropelvic junction obstruction 15 pyeloplasties were performed with the Da Vinci Surgical System. With the patient in a lateral semiprone position the retroperitoneal space was developed by blunt and balloon dissection. Three ports were placed for the computer assisted system and 1 for assistance. Pyeloplasty was performed with the mounted system placed behind the patient. RESULTS: The procedures were completed in all patients with the computer assisted system. Median operative time was 173 minutes (range 76 to 215) and there were no perioperative complications. Median postoperative hospital stay was 2 days (range 1 to 3). Two patients had postoperative complications related to the Double-J catheter (Cook Urological Inc., Spencer, Indiana). In 1 patient the catheter was displaced with its lower end in the distal ureter, and the other patient was rehospitalized with occlusion of the catheter and treated with nephrostomy for a few days. All patients had a satisfying outcome during the preliminary followup period of 1 to 7 months. CONCLUSIONS: In this the first series of computer-assisted retroperitoneal pyeloplasty in children the method seems feasible with shorter operative time and similar complications as in standard retroperitoneoscopic procedures but easier handling of the instruments and shorter training for the surgeon. The costs for the system are still high and only longer followup will reveal whether the more precise placement of sutures and the advantage of the magnified 3-dimensional view lead to at least the same results as the open procedure.

Male fetal pig lower urinary tract function. Part II: free voiding pattern close to term and in the newborn.

PURPOSE: We assessed the development of natural voiding function late in gestation and in the immediate postnatal period in a porcine model. MATERIALS AND METHODS: The study comprised 7 male fetal minipigs (median age 94 days, 0.88 gestation) and 7 male newborn pigs. In all pigs an ultrasonic probe was placed around the subcutaneous urethra and pressure catheters were placed in the bladder and rectum and in the amnionic cavity in the fetal pigs. The catheters were connected to pressure transducers as the flow probe was connected to a flow meter, and the recordings were sampled at a rate of 10 Hz on a personal computer. RESULTS: The newborns had a median voiding frequency of 3.3 times per hour while the fetuses voided a median of 5.9 times per hour (p = 0.16). Both groups voided with a staccato flow at a frequency of 1 to 2 Hz, indicating voiding dyscoordination between the detrusor and urethra. Maximum flow rate increased from median 4.4 ml per minute (range 2.0 to 8.8) in the fetal group to median 10.9 (5.4 to 18.3) in the newborns (p = 0.07). While the minimum opening pressure remained unchanged (median 7.0 cm H2O, range 5.7 to 13.0) vs median 7.6, (range 7.7 to 14.0, p = 0.57) the detrusor pressure at maximum flow decreased from median 22.4 cm H2O (range 16.6 to 39.0) in the fetal pigs to 12.1 cm H2O (8.3 to 22.3) in the newborns. CONCLUSIONS: Fetal and newborn pigs have dyscordinated voiding with a staccato flow. While the urethral opening pressure appears to be unchanged, the detrusor pressure at maximum flow decreases during the last period of gestation, indicating decreased urethral resistance. These findings are in accordance with observations made in human infants.

Effects of high frequency deep brain stimulation on urine storage and voiding function in conscious minipigs.

AIMS: Suprapontine neural integration during the storage phase is decisive for the timing of voiding. Neurological disorders like Parkinson's disease are thus frequently complicated by bladder dysfunction. The aim of the present study was to investigate the effect of high frequency deep brain stimulation on the urine storage and voiding function in conscious Parkinsonian minipigs. MATERIALS AND METHODS: Five Goettingen minipigs had a Parkinsonism-like state induced by intoxication with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). An electrode for chronic stimulation was placed unilaterally in the subthalamic nucleus. The effect of stimulation was determined by the outcome of transurethral cystometries performed with the stimulation in on- and off-mode. RESULTS: Of 20 planned cystometry-sessions 18 were completed. Six incomplete voidings occurred in stimulation on-mode and five in off-mode. Interruption of the stimulation for 2 days was followed by a significant increase in pressure rise on filling to cystometric capacity, from 7 to 21 cmH(2)O (P = 0.005), and an insignificant reduction in cystometric capacity from 30 to 26 ml/kg bodywt. (P = 0.370), leading to a significant decrease in bladder compliance from 124 to 34 ml/cmH(2)O (P = 0.013). CONCLUSIONS: Transurethral cystometry was a feasible examination technique in pigs. The findings demonstrate that high frequency deep brain stimulation changes the bladder characteristics in the storage phase. Since bladder pressure and capacity responded differently to interruption of stimulation distinct neural mechanisms must be involved in the modulation of sensory information on bladder tension and stretch.

Bladder and urethral responses to pelvic nerve stimulation in the pig.

OBJECTIVE: The aim of our study of the pig was to investigate the responses of smooth muscle of the bladder and the urethral sphincter to preganglionic parasympathetic stimulation, and to assess the effect on the lower urinary tract of IV administration of alpha,beta-methylene-ATP. MATERIALS AND METHODS: In seven anaesthetised female pigs, the responses to repeated 20 s pelvic nerve stimulations before and after IV administration of 0.02 mg/kg alpha-beta-methylene-ATP, and the responses to the drug itself, were recorded in the bladder and the urethra separately. RESULTS: In the urethral high-pressure zone, pre-stimulation pressure was a mean of 61+/-11 cmH2O. During pelvic nerve stimulation, urethral pressure declined by 48+/-9 cmH2O, while the bladder pressure increased to 30+/-18 cmH2O. The rate of pressure changes during the first 3 s of stimulation (initiation of voiding) was larger in the urethra than in the bladder (urethral pressure decrease: 13.0+/-3.1 cmH2O/s, bladder pressure increase: 3.2+/-2.5 cmH2O/s). Administration of alpha,beta-methylene-ATP was followed by a significant but temporary enlargement in the bladder response to pelvic nerve stimulation to 36+/-20 cmH2O, p = 0.028, n = 7, but no change in urethral response. CONCLUSIONS: At least 80% of the urethral pre-stimulation pressure was exerted by the smooth muscle. The synergic activation of the detrusor and the urethral smooth muscle in response to preganglionic parasympathetic nerve stimulation was controlled by the peripheral nerves or by the neuromuscular transmission. Administration of alpha,beta-methylene-ATP increased the bladder response to pelvic nerve stimulation without changing the urethral response.

Severe partial ureteric obstruction in newborn rats can produce renal dysplasia.

OBJECTIVE: To investigate whether partial unilateral ureteric obstruction (PUUO) produces renal dysplasia in newborn rats. MATERIALS AND METHODS: Left mild (in 31) or severe (in 34) PUUO was induced in 2-day-old rats by embedding a quarter or two-thirds of the ureter into the psoas muscles, respectively. Sham-operated control rats (36) were assessed in parallel. Kidney morphology, renal parenchymal weight and histology were examined 24 weeks and 30 months afterward. RESULTS: There was significant pelvic dilatation in all obstructed kidneys; four kidneys were dysplastic in those severely obstructed, with a significant decrease in renal volume. There were three dysplastic kidneys after 6 months and one at 30 months. The in vitro dysplastic kidney weight was 36% of the control kidneys. Microscopy showed primitive glomerular and tubular structures, with renal parenchymal developmental disorganization and marked fibrosis. The glomeruli, tubules and collecting ducts were deficient in number and had often undergone cystic changes. Columnar tubular epithelium and peritubular mesenchymal collars were present. There was no renal dysplasia in the mildly obstructed and sham-operated rats. The parenchymal weight of the kidneys contralateral to the dysplastic kidneys was significantly higher than in the controls (P < 0.001). CONCLUSIONS: Severe PUUO can produce renal dysplasia in newborn rats. However, only 12% with severe obstruction had renal dysplasia, indicating that the cause of renal dysplasia might also be related to other factors.

Partial unilateral ureteropelvic junction obstruction induced in 2-week-old piglets.

PURPOSE: We examined effects on kidney function and morphology of a partial ureteropelvic junction obstruction induced late in the postnatal nephrogenesis period of the pig. We compared the results to a similar study on pigs with obstruction induced early in the nephrogenesis period. MATERIALS AND METHODS: A total of 20 14-day-old pigs were included in the study. Fifteen animals were randomized to partial unilateral obstruction and 5 were sham operated. Kidney function and morphology were analyzed regarding glomerular filtration rate, renographic functional share and total kidney volume at the age of 4, 12 and 24 weeks. RESULTS: At age 4 weeks hydronephrosis was found in all obstructed kidneys included in the study. Four obstructed kidneys had renographic functional share 40% or greater and 1 deteriorated to less than 40% at 24 weeks. A total of 11 obstructed kidneys had a functional share less than 40%, 5 increased to a share greater than 40% at age 24 weeks and 3 had decreasing share from age 4 to 24 weeks. Single kidney glomerular filtration rate of the contralateral kidneys was significantly increased at all ages. Volume of the contralateral kidney was significantly increased at age 4 and 12 weeks. CONCLUSIONS: The variability and course of renographic functional share in kidneys subjected to partial obstruction at age 2 weeks was similar to findings obtained in pigs obstructed at age 2 days. In contrast to these our study showed compensatory increase in function and size of the contralateral kidney, suggesting that contralateral compensation is an ability gained late in the nephrogenesis period.

Male fetal pig lower urinary tract function in mid second and early third trimester of gestation.

PURPOSE: Routine use of ultrasound during pregnancy has emphasized the need for greater knowledge about normal and abnormal voiding function during fetal live. We describe the developmental changes in lower urinary tract function from the middle of the second to the early third trimester of gestation. MATERIALS AND METHODS: The study included 22 male fetal pigs of 13 pregnant Goettingen minipigs (gestational period 111 to 115 days) with 11 fetuses in the middle of the second (median 61.5 days, 0.55 of term) and 11 fetuses in the beginning of the third trimester of gestation (median 80 days, 0.72 of term). With the sow under isoflurane anesthesia catheters were placed in the bladder, rectum and amniotic cavity of the fetuses, and a flow probe was placed around the distal urethra. After the sow was at light sleep urethral flow, amniotic pressure, abdominal pressure and bladder pressure were recorded a median of 241 minutes. RESULTS: The recordings of 14 fetuses were evaluable. In the middle of the second trimester the fetuses showed an almost constant dribbling with a median flow of 0.2 ml. per minute and a median of 4 concomitant bladder contractions per minute of median 3.5 cm. H2O (detrusor pressure). At the beginning of the third trimester the fetuses had periods of staccato flow (median 0.2 ml. per minute, staccato frequency 1 to 2 Hz.) on top of contractions (median 4 contractions per minute, median detrusor pressure 5.5 cm. H2O) with no flow between voidings. CONCLUSIONS: Development of storage and voiding function in male pigs occurs between the mid-second and early third trimester of gestation, together with emergence of striated sphincter bursting activity, which interrupts flow in the urethra during the voiding phase.

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.