Microangiopathy and mild mixed neuromyopathic alterations in a patient with homozygous PIEZO-2 mutation.

We report a 9-year-old girl homozygous for a loss-of-function mutation in the PIEZO-2 gene. She showed generalized muscular hypotonia with severe scoliosis, joint deformities, deficient proprioceptive function and selective atrophy and signal alterations of both gastrocnemii on whole body MRI scan. Light microscopic and ultrastructural examination showed few atrophic fibres, abnormal mitochondria, focal myofibrillar disruption and endomysial capillary microangiopathy.

A continent urinary diversion in a female with agenesis of the bladder: a 5-year follow-up.

There are few case reports of bladder agenesis. The outcome of the patients differs and depends on the associated malformations. Different urinary diversions are described to save renal function. Most of the surviving patients with bladder agenesis have undergone incontinent urinary diversions as primary treatment. We describe the case of a female infant with agenesis of the bladder that arrived in our institution after several septic episodes. Treatment of choice was a continent pouch with an appendicovesicostomy. We state that even in young children, a primary continent urinary diversion can be performed with excellent long-term outcome.

Ultrastructural analysis of vascular calcifications in uremia.

Accelerated intimal and medial calcification and sclerosis accompany the increased cardiovascular mortality of dialysis patients, but the pathomechanisms initiating microcalcifications of the media are largely unknown. In this study, we systematically investigated the ultrastructural properties of medial calcifications from patients with uremia. We collected iliac artery segments from 30 dialysis patients before kidney transplantation and studied them by radiography, microcomputed tomography, light microscopy, and transmission electron microscopy including electron energy loss spectrometry, energy dispersive spectroscopy, and electron diffraction. In addition, we performed synchrotron x-ray analyses and immunogold labeling to detect inhibitors of calcification. Von Kossa staining revealed calcification of 53% of the arteries. The diameter of these microcalcifications ranged from 20 to 500 nm, with a core-shell structure consisting of up to three layers (subshells). Many of the calcifications consisted of 2- to 10-nm nanocrystals and showed a hydroxyapatite and whitlockite crystalline structure and mineral phase. Immunogold labeling of calcification foci revealed the calcification inhibitors fetuin-A, osteopontin, and matrix gla protein. These observations suggest that uremic microcalcifications originate from nanocrystals, are chemically diverse, and intimately associate with proteinaceous inhibitors of calcification. Furthermore, considering the core-shell structure of the calcifications, apoptotic bodies or matrix vesicles may serve as a calcification nidus.

Different types of scaffolds for reconstruction of the urinary tract by tissue engineering.

INTRODUCTION: Tissue engineering is an important and expanding field in reconstructive surgery. The ideal biomaterial for urologic tissue engineering should be biodegradable and support autologous cell growth. We examined different scaffolds to select the ideal material for the reconstruction of the bladder wall by tissue engineering. MATERIALS AND METHODS: We seeded mouse fibroblasts and human keratinocytes in a co-culture model on 13 different scaffolds. The cell-seeded scaffolds were fixed and processed for electron microscopy, hematoxylin and eosin stain, and immunohistochemistry. Cell density and epithelial cell layers were evaluated utilizing a computer-assisted optical measurement system. RESULTS: Depending on the growth pattern, scaffolds were classified into the following three distinct scaffold types: carrier-type scaffolds with very small pore sizes and no ingrowth of the cells. This scaffold type induces a well-differentiated epithelium. Fleece-type scaffolds with fibers and huge pores. We found cellular growth inside the scaffold but no epithelium on top of it. Sponge-type scaffolds with pores between 20 and 40 microm. Cellular growth was observed inside the scaffold and well-differentiated epithelium on top of it. CONCLUSION: To our knowledge, this is the first time three distinct scaffold types have been reported. All types supported the cell growth. The structure of the scaffolds affects the pattern of cell growth.

Bladder wall replacement by tissue engineering and autologous keratinocytes in minipigs.

OBJECTIVE: To develop a tissue-engineered bladder wall replacement with autologous cells and a biodegradable scaffold, as whenever there is a lack of native urological tissue the bladder is reconstructed with different bowel segments, which has inevitable complications. MATERIAL AND METHODS: Skin biopsies were taken from six minipigs, and primary fibroblast and keratinocyte cell cultures established. A partial resection of the urinary bladder was reconstructed by a cell-seeded scaffold covered with completely differentiated epithelium and supported by a mucosa-free pedicled ileum graft. Each pig was assessed urodynamically and by cystography before operation and every month until explantation; the pigs were killed at 1, 2 and 3 months after augmentation. Control groups (of six pigs each) with bladder augmentation with complete or denuded ileum were used. The bladders were assessed histologically and by distensibility measurements RESULTS: The differentiated keratinocyte epithelium was still present on the reconstructed bladder wall after 3 months. The overall shrinkage rate was 6.5%. The engineered bladder wall had lower distensibility than the native one. The inflammatory reaction present initially had disappeared after 3 months. CONCLUSIONS: The implanted, tissue-engineered substitution of the bladder wall is not only a bridging graft, but also a complete reconstruction. With this model, extended bladder wall substitution seems feasible and should be investigated in further studies.

Iatrogenic urethral strictures following pull-through procedures: buccal mucosa inlay repair.

BACKGROUND: Damage to the male urethra following pelvic surgery for anorectal malformations (ARM) is a well known problem, usually seen in boys with rectourethral fistulas. Urethral strictures located in the posterior urethra are difficult to treat because surgical exposure of the posterior urethra is difficult and conventional reconstructive procedures do not consistently yield good results. Free buccal mucosa grafts placed either ventrally or dorsally have shown superior results to other techniques. We herein describe our technique of urethral reconstruction in three boys with iatrogenic strictures of the posterior urethra following pull-through procedures. METHODS: Exposure of the posterior urethra was achieved by a posterior sagittal approach. In a boy with Hirschsprung's disease a trans-anorectal approach was used and in two boys with ARM the anus and rectum were fully mobilized. The posterior urethra was opened in the midline ventrally and the stricture was incised dorsally. A free buccal mucosal graft was placed and sutured into the incision. The urethra was closed dorsally and the bowel reconstructed. RESULTS: Mean age at operation was 22 months (9-39 months) and mean follow up was 17 months (6-22 months). No patient developed complications due to the operation. Stenting of the urethra was done with a silicone Foley catheter for 14 days. All three boys were able to void spontaneously following the operation and were continent for urine. No urinary tract problems developed. Both boys with ARM had colostomies which were closed 6 weeks later. Both are socially continent for feces. The boy with Hirschsprung's disease had no colostomy for the procedure and is fully continent. CONCLUSIONS: The buccal mucosa inlay repair procedure via a posterior sagittal approach yields good results with low morbidity. Exposure of the posterior urethra is excellent with this approach, which we thus recommend in boys with posterior urethral strictures. However, the surgeon should be very experienced with anorectal surgery and the posterior sagittal approach.

Urethroplasty in female-to-male transsexuals.

OBJECTIVE: Female-to-male transformation includes total phallic reconstruction. Construction of a neourethra is necessary to achieve the goal of voiding while standing; however urethral fistula and stricture formation occur in a significant percentage of patients. METHODS: 25 patients with primary female transsexualism underwent phalloplasty with a free radial forearm flap, vaginectomy and urethroplasty in a one-stage procedure. In 16 of these patients the fixed part of the neourethra ("bulbar urethra") was constructed from a vaginal flap. In 9 patients flaps of the labia minora (5 patients) or the "urethral plate" (4 patients) were used. RESULTS: In 14 (58%) patients fistulas and/or strictures in the newly constructed urethra occurred. 11 (69%) of 16 patients in whom the "bulbar urethra" was constructed from a vaginal flap experienced fistulas and/or stricture formation. Fistulas and/or strictures occurred in 3 of 5 patients with labia minora flaps and none of 4 patients with the urethral plate procedure. Repair of fistula and strictures was performed by primary closure of fistulas, staged urethroplasty with local pedicle flaps or distant tissue grafts using buccal mucosa (2-6 procedures). CONCLUSION: One-stage total phalloplasty and urethroplasty is associated with a significant rate of fistulas and strictures. However, these complications can be corrected by the techniques used in modern urethral surgery.