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.

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.

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.

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.

Constant perfusion provocation in idiopathic hydronephrosis.

Twenty-two hydronephrotic units in 20 patients underwent preoperative pressure flow study in combination with electromyographic study of pelvic and ureteric peristalsis. Ten units had a continuous pressure rise during perfusion, whereas the rest had a stabilization of the intrapelvic pressure below 20 cm. of water. The high pressure group was identical with the low pressure group concerning degree of hydronephrosis judged by intravenous urography and function judged by the two-minute uptake of isotope on the renogram. The major difference was the presence of aberrant vessels which were present in 7 of 10 high pressure units and absent in 8 of 12 low pressure units. Long-term records prior to surgery were obtainable in only 1 patient who had spontaneous progression of hydronephrosis during a ten-year period. This unit had a low pressure response to perfusion. The investigation seems to indicate that pressure flow studies might reveal external obstruction, an obstruction which might not be fundamental to the course of the disease. More studies are needed before consequence are to be taken from urodynamic studies of the upper urinary tract.

Experimental and clinical experience with new pyeloureteral stents in pediatric urology.

In light of the many problems with the use of conventional external stents in supravesical reconstructive urinary tract surgery in children; e.g. the risk of infection, urodynamic malfunction, and lack of flexibility insertion methods, the return to internal pyeloureteral stenting is a much discussed topic in pediatric urology. In order to improve the generally unsatisfactory situation, we developed, together with the Rüsch Co., a new type of directable and deconnectable ureteral stent. This polyurethane catheter features a membrane valve made of soft Wiruthan at the bladder end, which closes automatically with increasing bladder pressure. Thus, urinary backflow from the urinary bladder into the renal pelvis is prevented. Experimental data from antireflux stenting justify the clinical use of such a stent in children, as the urodynamic in vivo criteria and requirements were fulfilled completely. We now have clinical experience with the application of 340 pyeloureteral DD stents in 241 children from 1993 through 1996; 259 stents were inserted intraoperatively, and 81 stents were applied by endoscope. It was impressive that secondarily, renal function that had been considerably reduced could be regained and stabilized by long-term stenting, even in some older children with chronic supravesical ureteral obstruction. Although small technical details have to be clarified, such as simplification of stent retrieval and an antireflux valve that can be applied using an anterograde approach, the DD valve stent used in this patient population after reconstruction of a malformed supravesical urinary tract can be recommended without any reservations.

Classification of handwritten digits using a RAM neural net architecture.

Results are reported on the task of recognizing handwritten digits without any advanced pre-processing. The result are obtained using a RAM-based neural network, making use of small receptive fields. Furthermore, a technique that introduces negative weights into the RAM net is reported. The results obtained on the task of recognizing handwritten digits is comparable with the best performances reported in the literature.

[Topical steroids in the treatment of phimosis in children]. / Lokal steroidapplikation i behandlingen af phimosis hos børn.

The aim of this study was to evaluate the efficacy of steroid application in the treatment of childhood phimosis. In a consecutive study 91 boys were treated with application of topical betamethason 0.05% cream twice daily. The foreskin was treated for one month, with an attempt at foreskin retraction after fourteen days. Treatment was controlled after one month and six months. Sixty boys achieved full retraction of the foreskin and nine had partial retraction and relief of symptoms. Twenty-two boys had unsatisfactory response and had an operation. Forty-five boys were controlled after six months, 13 had recurrence, of these nine were satisfied and free of symptoms, two had a new steroid treatment with full success, and two wanted a circumcision. A total of 74% did not need an operation after topical steroid treatment. No side-effects or complications were registered. Childhood phimosis can be successfully treated with steroid application, and the treatment should be offered prior to an operation.

[Anderson-Hynes pyeloplasty in hydronephrosis]. / Anderson-Hynes-pyeloplastik ved hydronefrose.

The purpose of the study was to evaluate pyeloplasty a.m. Anderson-Hynes in the treatment of hydronephrosis in a large series of patients. In 175 patients, consecutively operated for ureteropelvic junction obstruction, we found 24 (14%) with minor postoperative complications, mostly urinary tract infection. Six patients (3%) were reoperated because of continued pain and obstructed drainage postoperatively. There was a small, but statistically significant increase in renal functional share on the operated side. We found a highly significant correlation between postoperative changes in total GFR and single kidney GFR on the operated side, which suggests a real improvement in renal function, rather than a simple reallocation of function between the two kidneys. We conclude that newer treatment modalities known as "minimally invasive surgery" must give comparably good results in order to be an acceptable alternative to traditional dismembered pyeloplasty.

[Treatment of anal incontinence and constipation with transanal irrigation]. / Behandling af analinkontinens og obstipation ved hjaelp af transanal irrigation.

The Enema Continence Catheter (ECC) consists of a rectal catheter with an inflatable balloon. The balloon keeps the catheter in the rectum, while enemas are administered. Results from 25 adult patients and 12 children treated with the ECC were evaluated by telephone interviews or by information drawn from patient records. The ECC reduced the frequency of incontinence episodes in four of nine (44%) adult patients suffering from faecal incontinence due to spinal cord lesions, myelomeningocele, complicated anal sphincter lesions or anorectal surgery and irradiation therapy. Among 16 adult patients suffering from constipation or obstructed defecation, the ECC reduced symptoms in three (19%). Furthermore, the ECC procedure reduced symptoms in 10 of 11 (91%) children with colorectal dysfunction, mainly due to spina bifida. In conclusion, the ECC can reduce symptoms in most children suffering from faecal incontinence or constipation, and in some adults with faecal incontinence. However, the method is less effective among adults with constipation or obstructed defecation.

Alarm treatment: influence on functional bladder capacity.

Home recordings were used to study the effect of alarm treatment, over a period of 6 weeks, in children with monosymptomatic nocturnal enuresis. Vasopressin day/night ratios were shown to be a good indicator of alarm treatment success. Serial measurement of plasma vasopressin levels is, however, unsuitable for use in the clinic, as extensive analyses would have to be performed to obtain the necessary results. Use of an alarm increased nocturnal bladder capacity, but had no effect on daytime bladder capacity, sleep patterns, vasopressin secretion, nocturnal urine output or pelvic floor activity. In addition, the results of the study suggest that an alarm treatment period of 2 months would lead to more successful results than the 6 weeks used in the study.

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.

Initial experience with percutaneous nephrolithotomy: results, problems and complications.

Initial experience from 132 cases of percutaneous lithotripsy performed at three departments in Arhus County in 1984-85 is reviewed. Twenty patients were not offered a percutaneous operation during this period. In 12 cases the stone had to be removed by open operation. Another 12 cases were also regarded as failures due to important residual stones or fragments. Stone free kidneys were obtained in 86 cases (64%), whereas 22 (17%) had minor residual stones or fragments considered unimportant in relation to the present indications for operation. Stones 20 mm in diameter, and especially staghorn stones frequently gave failures. Minor complications were recorded in 29 patients and resulted in 7 open operations, mostly from the early part of the series. Five severe complications were seen. An old weak man died from late complications after bleeding. The four others were operated for pulmonary embolism (1 pt), late bleeding (traumatic aneurysm, 2 pt) and colonic perforation (1 pt). They all recovered.

Vesico-ureteral reflux. II. The longterm outcome of kidney function in non-surgical treatment.

Seventy one patients were included in a prospective study of non-surgical treatment of vesico-ureteral reflux (VUR). We found 111 refluxing ureters, with 20 grade 1, 4 grade 2, 41 grade 3, 5 grade 4 and 1 grade 5. There was no correlation between presenting symptoms and degree of VUR or nephropathy, or between renal function in terms of glomerular filtration rate. During followup the patients were treated with long-term low-dose antibiotic prophylaxis and voiding disorders were corrected pharmacologically or by micturitional training. With a median follow up time of 6 years (3-10) 63% of the patients had cessation or down grading of VUR, irrespective of initial VUR degree. There was no correlation between cessation rate and urodynamic parameters, GFR, history of enuresis or previous urinary infections. The study supports a non-surgical attitude towards VUR patients irrespective of VUR degree, with prophylaxis of urinary infections and possibly correction of voiding disorders.

Vesico-ureteral reflux. I. Renal function and morphology in relation to anamnestic and urodynamic parameters.

Hundred and one children aged 12 years or less were consecutively referred with non-neurogenic vesico-ureteral reflux. None of the patients were previously operated for reflux. Based on the degree of reflux and the degree of nephropathy judged from urograms or renoscintigrams the patients were assigned an index defined as the sum status of both nephro-ureteric units. We found no correlation between VUR index, nephropathy index and GFR on one side, and bladder function parameters (spontaneous voiding, cystometry, bladder activity during sleep) on the other. Further, no correlation was found to history concerning urinary tract infections or enuresis the year before admittance. Possible reasons for the lack of correlation are discussed.

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.

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.

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.