Optical response of photopolymer materials for holographic data storage applications.

We briefly review the application of photopolymer recording materials in the area of holographic data storage. In particular we discuss the recent development of the Non-local Polymerisation Driven Diffusion model. Applying this model we develop simple first-order analytic expressions describing the spatial frequency response of photopolymer materials. The assumptions made in the derivation of these formulae are described and their ranges of validity are examined. The effects of particular physical parameters of a photopolymer on the material response are discussed.

Autoaugmentation peritoneocystoplasty in a sheep model.

OBJECTIVE: To report our experience with autoaugmentation peritoneocystoplasty (AAPC) in a sheep model, and to compare the results with autoaugmentation gastrocystoplasty (AAGC) in a sheep model and in paediatric patients. MATERIALS AND METHODS: Ten 6-month-old male lambs underwent bladder augmentation by detrusorotomy. A flap of parietal peritoneum, dissected from the anterior abdominal wall, was used to cover the bladder mucosa. The sheep were evaluated by urodynamics 6 months after surgery. Bladder compliance (bladder volume/intravesical pressure) was calculated for the bladder capacity at leakage. The urodynamic results were compared with age-matched control sheep and with 12 sheep that had undergone AAGC; the results were assessed using the Mann-Whitney U-test. RESULTS: In two of the 10 sheep, bladder volumes after AAPC increased by > 100%, although for the group, the mean (range) bladder volume after augmentation, at 159 (42-261) mL, was not significantly different from that before surgery (mean 143 mL). Bladder volumes after AAPC were not significantly different from those in the control sheep (mean 205 mL) but were significantly less than in the AAGC group (mean 317 mL; P < 0.05). Bladder compliance at leak capacity in the AAPC group (mean 5.4 mL/cmH2O) was also not significantly different from the controls (mean 9.1 mL/cmH2O), but was lower than the in the AAGC animals (median 14.6 mL/cmH2O; P < 0.05). CONCLUSIONS: AAPC in a sheep model does not result in a reliable increase in bladder volume or compliance. The volume and compliance are inferior to those found in bladders augmented by AAGC.

[Posterior urethral valves: a change of concept]. / Válvulas de uretra posterior: un cambio de concepto.

OBJECTIVE: The basic question proposed in this article is whether early diagnosis and treatment of children with posterior urethral valves can prevent bladder and upper tract deterioration. If so, which is the best treatment? METHODS/RESULTS: Results with temporary urinary diversion for children with posterior urethral valves and renal insufficiency have not fulfilled expectations of an improved long-term outcome. Furthermore, there is mounting evidence that proximal urinary diversion with complete early bladder defunctionalization may result in reduced bladder capacity and compliance. In our experience early bladder cycling following valve ablation in the neonatal period is critical for the initiation of the healing process. Regardless of the initial appearance of the bladder and the status of the upper tract, early valve ablation may offer the best chance at functional recovery of normal bladder function, and restoration of upper tract function and anatomy without reconstructive surgery. In our series of 23 boys whose valves were resected at a mean of 21 days, bladder trabeculation resolved in 85% at one year. Follow up varied between 1 and 9 years. When compared to infants treated with urinary diversion, these children achieved superior potty training results. CONCLUSION: Bladder healing with early ablation seems to be dependent on bladder filling and emptying (cycling) with low outflow resistance. Ultimately, maximum recovery of renal function will depend on preventing the development of a hostile bladder. Early valve ablation may best achieve both goals of maximum bladder and renal functional recovery.

Enteric mucosal regrowth after bladder augmentation using demucosalized gut segments.

PURPOSE: Regrowth of the enteric mucosa on a denuded muscular flap enterocystoplasty is an undesirable complication of demucosalized enterocystoplasty. This study was performed to understand how regrowth can be prevented and, thus, a complete urothelial lined enterocystoplasty can be achieved. MATERIALS AND METHODS: We performed bladder augmentation on 30 sheep using demucosalized seromuscular gastric or colonic flaps with or without autoaugmentation. The epithelium and muscularis mucosae were completely removed from the gastric flap. Initial attempts to remove the muscularis mucosae and most of the submucosal layer from the colonic flap by cautery caused bleeding and muscle damage. Thus, demuscosalization was done by stripping with forceps, in which the muscularis mucosae and submucosa remained largely intact on the colonic flap. Sheep were sacrificed 4 to 12 months postoperatively and bladders were inspected for mucosal regrowth. Subsequently autoaugmentation with demucosalized seromuscular gastric or colonic flaps was performed clinically in 10 children in whom the enteric epithelium and muscularis mucosae were removed completely with part of the submucosa by dissection through the submucosal plane. These children were followed with urodynamic studies and mucin staining of urine up to 39 months postoperatively. RESULTS: Regrowth of islands of enteric mucosa occurred in 4 of the 5 animals in which the muscularis mucosae and submucosal layers were preserved on a colonic flap. In all animals with mucosal regrowth the bowel was prepared by stripping the mucosa. Mucosal regrowth did not occur in any animal after complete removal of the muscularis mucosae and the inner portion of the submucosa from the stomach or colon. All patients had satisfactory urodynamic results and no evidence of enteric mucosal regrowth. CONCLUSIONS: Removal of the muscularis mucosae with the inner portion of the submucosa appears necessary to prevent enteric mucosal regrowth on the muscular flap of a demucosalized enterocystoplasty. In addition, this level of dissection does not seem to interfere with the success of bladder augmentation in children.

Lower urinary tract changes after early valve ablation in neonates and infants: is early diversion warranted?

PURPOSE: Severe hydronephrosis, high grade reflux and/or renal insufficiency often leads to proximal urinary tract diversion in male infants with posterior urethral valves. Even with this treatment progressive loss of renal function often occurs. Unfortunately with early diversion the bladder, already damaged by in utero obstruction, is also defunctionalized. Alternative treatment with valve ablation in the newborn period and without diversion may facilitate recovery of normal bladder function. MATERIALS AND METHODS: We retrospectively reviewed the records of infants treated for posterior urethral valves before age 1 year at our institution in the last 8 years. Treatment comprised primary valve ablation in 23 patients and urinary diversion in 8. Preoperative and serial postoperative voiding cystourethrograms were scored for degree of trabeculation, bladder neck hypertrophy and prostatic urethral dilatation in all patients undergoing primary valve ablation. Recovery of bladder and renal function after primary valve ablation was compared to that of patients treated with urinary diversion. RESULTS: All patients treated with primary valve ablation demonstrated marked improvement or resolution of bladder abnormalities on voiding cystourethrography by 1 year postoperatively. Bladder compliance and volume were statistically better than in patients treated with primary diversion. Upper tract diversion failed to halt progressive renal failure in 5 of the 6 patients who underwent diversion. Similarly primary valve ablation did not stop progressive renal failure in a matched group of patients. CONCLUSIONS: Early ablation of posterior urethral valves results in the recovery of normal bladder appearance and function when performed in the first months of life. Severe renal insufficiency tends to progress even with upper tract diversion. Furthermore, this treatment prevents normal bladder cycling, which may inhibit bladder recovery in the patient with posterior urethral valves.

Continent gastric tube: new techniques and long-term followup.

PURPOSE: The successful use of stomach for bladder augmentation and substitution is well documented. Gastric tissue has been used more recently to create continent catheterizable tubes. We describe 2 new techniques of gastric tube construction, and report our long-term followup of catheterizable gastric tubes in children and adults undergoing complex urinary tract reconstruction. MATERIALS AND METHODS: A retrospective chart review of 6 male and 4 female patients 5 to 43 years old was done. Primary diagnoses included bladder exstrophy, cloacal exstrophy, rhabdomyosarcoma and neurogenic bladder. Five patients underwent gastrocystoplasty with simultaneous creation of a continent gastric tube from the anterior gastric flap. In 2 patients who had undergone previous gastrocystoplasty a continent gastric tube was created from an anterior flap raised from the existing gastric bladder. Isolated gastric tubes were constructed in 3 patients. RESULTS: Followup ranged from 2 to 9 years (median 3.5). All patients demonstrated easy reliable catheterization. One patient required revision of the proximal end of the tube for incontinence. At followup all tubes were continent. Complications occurred only in flush or protuberant stomas, and resolved after stomal revision with recessed skin flaps. CONCLUSIONS: Several techniques can be used to create a continent gastric tube. Long-term followup reveals reliable catheterization and good continence rates. Recession of the gastric tube stoma with a skin flap prevents peristomal complications.

Interstitial cystitis in children.

PURPOSE: Interstitial cystitis has been rarely reported in children. We present our experience with 16 children in whom clinical symptomatology and cystoscopic findings were consistent with the diagnosis of interstitial cystitis. MATERIALS AND METHODS: We retrospectively reviewed the charts of 20 children referred for chronic sensory urgency, frequency and bladder pain who underwent cystoscopy and hydrodistension. Four patients were excluded from study because of infection identified at cystoscopy or lack of cystoscopic changes with hydro-distension. RESULTS: Patient age at onset of first symptoms ranged from 2 to 11 years (median 4.5) and age at diagnosis ranged from 3 to 16 years (mean 8.2). Of the 16 children 14 (88%) presented with symptoms of urinary frequency and sensory urgency, and in 13 (81%) lower abdominal pain was relieved by voiding. None of the children had motor urgency. Urodynamic evaluation in 8 cases revealed early bladder sensation with no evidence of involuntary bladder contractions. Diffuse glomerulations and terminal hematuria were demonstrated in all patients after hydro-distension. Followup was available for 14 patients. Relief of symptoms occurred after hydro-distension in all children except 1. Seven children (50%) required repeat hydro-distension. CONCLUSIONS: Children with symptoms of bladder pain, urinary frequency and sensory urgency have bladder changes on cystoscopy consistent with interstitial cystitis. Although rare, this condition is recognizable and it should not be confused with dysfunctional voiding in which complaints are secondary to involuntary bladder contractions.

Early primary valve ablation for posterior urethral valves.

Early diagnosis and the use of new pediatric endoscopic equipment have significantly improved the survival of infant boys with posterior urethral valves. The sequelae of urethral obstruction in these patients includes abnormalities in the urethra, bladder, ureters, and kidneys. The question remains of how best to treat all valve patients to maximize function of the entire urinary tract. Our experience with early valve ablation (EVA) suggests that the damaged bladder and upper tracts have a potential to heal if the obstruction is removed and the bladder is allowed to fill and empty cyclically in the first few months of life. One year after EVA, even patients with severe obstructive changes show return of normal bladder capacity and compliance, and resolution or improvement in reflux. Unfortunately, the renal insufficiency associated with valves often is secondary to primary renal dysplasia, with many patients progressing to renal failure and transplantation. Upper tract diversion has failed to improve long-term outcome in patients with renal dysplasia; furthermore, it jeopardizes the potential for bladder healing and normal bladder function. Therefore, even for patients with renal insufficiency, early primary ablation should be used as the definitive treatment for posterior urethral valves.

Cigarettes, alcohol and marijuana are related to pyospermia in infertile men.

The relationship of current use of cigarettes, marijuana and alcohol to the parameters of seminal fluid analysis, sperm penetration assay and sperm autoimmunity was studied in 164 men from infertile couples. Current cigarette smokers, marijuana users and heavy alcohol users showed greater numbers of leukocytes in the seminal fluid than did nonusers (p less than 0.02, less than 0.007 and less than 0.01, respectively). In addition, cigarette smokers had lower sperm penetration assay scores than nonsmokers (median 2.5 versus 8.0, p = 0.05). Users of cigarettes, marijuana or alcohol showed no decrease in sperm count, motility or percentage of oval sperm, and no difference in prevalence of antisperm antibodies compared to nonusers. After controlling for past sexually transmitted diseases and multiple substance exposures in a multivariate model, use of cigarettes (p = 0.006), marijuana (p = 0.12) or alcohol (p = 0.098) continued to be associated with a trend toward increased number of seminal fluid leukocytes. Cigarette smoking continued to show a significant decrease in sperm penetration assay score (p = 0.03).

The relationship of infection with Chlamydia trachomatis to the parameters of male fertility and sperm autoimmunity.

The relationship of past exposure to C. trachomatis to the parameters of male fertility was examined in men from infertile couples whose wives had no known female fertility factors. In this population, the frequency of C. trachomatis antibody was low. Past infection with C. trachomatis was associated with a history of nonspecific urethritis, and with the presence of sperm agglutinating antibodies in serum. We found no difference in the seminal fluid analyses, physical examinations, or sperm penetration assays of the men with or without chlamydial antibody.