Preliminary report: Surgical outcomes following genitoplasty in children with moderate to severe genital atypia.

INTRODUCTION: Prior studies of outcomes following genitoplasty have reported high rates of surgical complications among children with atypical genitalia. Few studies have prospectively assessed outcomes after contemporary surgical approaches. OBJECTIVE: The current study reported the occurrence of early postoperative complications and of cosmetic outcomes (as rated by surgeons and parents) at 12 months following contemporary genitoplasty procedures in children born with atypical genitalia. STUDY DESIGN: This 11-site, prospective study included children aged ≤2 years, with Prader 3-5 or Quigley 3-6 external genitalia, with no prior genitoplasty and non-urogenital malformations at the time of enrollment. Genital appearance was rated on a 4-point Likert scale. Paired t-tests evaluated differences in cosmesis ratings. RESULTS: Out of 27 children, 10 were 46,XY patients with the following diagnoses: gonadal dysgenesis, PAIS or testosterone biosynthetic defect, severe hypospadias and microphallus, who were reared male. Sixteen 46,XX congenital adrenal hyperplasia patients were reared female and one child with sex chromosome mosaicism was reared male. Eleven children had masculinizing genitoplasty for penoscrotal or perineal hypospadias (one-stage, three; two-stage, eight). Among one-stage surgeries, one child had meatal stenosis (minor) and one developed both urinary retention (minor) and urethrocutaneous fistula (major) (Summary Figure). Among two-stage surgeries, three children developed a major complication: penoscrotal fistula, glans dehiscence or urethral dehiscence. Among 16 children who had feminizing genitoplasty, vaginoplasty was performed in all, clitoroplasty in nine, external genitoplasty in 13, urethroplasty in four, perineoplasty in five, and total urogenital sinus mobilization in two. Two children had minor complications: one had a UTI, and one had both a mucosal skin tag and vaginal mucosal polyp. Two additional children developed a major complication: vaginal stenosis. Cosmesis scores revealed sustained improvements from 6 months post-genitoplasty, as previously reported, with all scores reported as good or satisfied. DISCUSSION: In these preliminary data from a multi-site, observational study, parents and surgeons were equally satisfied with the cosmetic outcomes 12 months after genitoplasty. A small number of patients had major complications in both feminizing and masculinizing surgeries; two-stage hypospadias repair had the most major complications. Long-term follow-up of patients at post-puberty will provide a better assessment of outcomes in this population. CONCLUSION: In this cohort of children with moderate to severe atypical genitalia, preliminary data on both surgical and cosmetic outcomes were presented. Findings from this study, and from following these children in long-term studies, will help guide practitioners in their discussions with families about surgical management.

Hydrogel coated mesh decreases tissue reaction resulting from polypropylene mesh implant: implication in hernia repair.

PURPOSE: Use of polypropylene mesh (PPM) in hernia repair is associated with tissue reactivity. We examined, in a rat model, a novel non-biodegradable hydrogel coated PPM which may allow for decreased inflammation and a decreased foreign body reaction. METHODS: Through a dorsal midline incision, a 2 cm × 2 cm section of PPM (either coated or uncoated) was placed on the fascial surface 1.5 cm from the incision on the dorsal wall of Sprague-Dawley rats. At 2 and 12 weeks after placement, the PPM and surrounding tissue were harvested. A board-certified dermatopathologist examined H&E stained slides for fibrosis and foreign body reaction. In addition, tissues were stained for apoptotic cells, oxidative damage, macrophages, fibroblasts, neovascularization and metalloproteases. RESULTS: At 2 and 12 weeks, there was a greater than 95 % decrease in foreign body giant cells in coated PPM samples compared to uncoated; fibrosis was decreased by 50 %. At 2 and 12 weeks, oxidative damage, fibroblast accumulation, apoptosis and macrophages were significantly decreased in coated PPM samples compared to uncoated PPM. CONCLUSION: These results demonstrate that a non-biodegradable hydrogel coating of PPM led to significant reduction in foreign body reaction, oxidative stress and apoptosis compared to uncoated PPM in vivo, and suggest that this coating could be clinically useful in hernia repair.

Hand-assisted laparoscopic autoaugmentation gastrocystoplasty.

BACKGROUND: Autoaugmentation gastrocystoplasty has been previously performed successfully. This set of experiments was conducted to determine the feasibility of performing autoaugmentation gastrocystoplasty laparoscopically. METHODS: Hand-assisted laparoscopic autoaugmentation gastrocystoplasty was performed on 15 mongrel dogs. The surgery was carried out with two 10-mm trocars and a 6-cm Pfannenstiel incision. The gastric wedge, supplied by the right gastroepiploic artery, was resected with two applications of an endoscopic gastrointestinal anastomosis (GIA) stapler. The pedicle was demucosalized, and the anastomosis to the bladder was completed through the Pfannenstiel incision. RESULTS: All of the dogs were successfully treated laparoscopically and were eating at 48 h. There was no evidence of anastomotic leak dehiscence at the gastric resection staple line. CONCLUSION: Hand-assisted laparoscopic autoaugmentation gastrocystoplasty can be performed successfully in dogs. This operation may offer a superior alternative to standard bladder autoaugmentation procedures in children suffering from congenital bladder disorders.

Hand-assisted demucosalized gastrocystoplasty comparing different tissue closure methods.

OBJECTIVES: To perform experiments to determine whether a new tissue sealant (SynthaSeal) could be an alternative for suture closure in minimally invasive bladder autoaugmentation gastrocystoplasty using demucosalized stomach. Alternative methods to suture closure for tissue approximation such as laser tissue welding and fibrin glue have been reported. METHODS: Minimally invasive autoaugmentation gastrocystoplasty with demucosalized stomach was performed on 14 female mongrel dogs. Two dogs were used to refine the technique. The remaining dogs were assigned to a suture group (n = 6) or a SynthaSeal group (n = 6). Anastomoses were performed using either SynthaSeal or suture. The in vivo bladder volumes and pressures of the groups were measured before and after gastrocystoplasty. The animals were studied on day 14. Samples of the anastomotic area were taken to measure the tensile strength and stress. Histologic analysis was conducted to assess tissue healing. The anastomotic time was recorded for each group. RESULTS: The tensile strength of the anastomoses in the SynthaSeal group was significantly increased (9.99 +/- 1.14 Newtons) compared with the suture group (5.66 +/- 0.97 Newtons) (P <0.05). The breaking stress comparisons and anastomosis times were equivalent between the two groups. The histologic evaluation revealed minor tissue devitalization and a normal inflammatory response in both groups. CONCLUSIONS: Minimally invasive gastrocystoplasty using demucosalized stomach can be successfully performed with SynthaSeal tissue sealant. This may provide a reliable alternative to suture closure.

Impact of solubility on laser tissue-welding with albumin solid solders.

BACKGROUND AND OBJECTIVE: The correlation between the solubility of solid albumin solders and their laser weld strength was investigated. STUDY DESIGN/MATERIALS AND METHODS: Sections of dog intestine were laser welded with soluble or insoluble solid strips of solder. Two different treatments were followed for tissue soldering: "wet weld" and "dry weld." These treatments were chosen to assess the impact of solubility on the repair strength. The laser power and radiation dose were 0.14 W and 14 J/mg, respectively. Calorimetric measures of solders were also performed. RESULTS: The moisture on the tissue partially dissolved the soluble strips at the tissue interface. Hence, the repair strength of the soluble solder was significantly stronger than the repair strength of the insoluble solder (0.22 N and 0.06 N, P < 0.0001). Temperature (approximately 70 degrees C) and enthalpy variation (approximately 1.4 J/g) for denaturing the soluble and insoluble solders were not significantly different (P > 0.05). CONCLUSION: The soluble solid solder behaved like dense liquid solder at the tissue interface. Hence, the interface strength of these two forms of solder should be similar. This correlation made it possible to identify an intrinsic limit for the weld strength of albumin solders.

Carotid artery anastomosis with albumin solder and near infrared lasers: a comparative study.

BACKGROUND AND OBJECTIVE: Laser tissue-welding has been used for anastomosis of carotid arteries. During welding, thermal injury sustained by the vessel walls should be minimized to prevent thrombosis. Two different types of lasers were used and effects on tissue damage were studied in vitro and in vivo. STUDY DESIGN/MATERIALS AND METHODS: End-to-end anastomosis of dog carotid arteries (n = 10) was performed by using a human albumin solder (HAS) in conjunction with Nd:YAG or diode lasers (lambda = 1.32 microm and 1.9 microm, respectively). The arteries were evaluated for patency and evidence of histologic injury after 21 days. Another group of arteries was laser soldered in vitro to measure the intimal and adventitial temperatures by using thermocouples. RESULTS: The arteries repaired with the diode laser sustained significantly less thermal damage than those repaired with Nd:YAG laser, both in vitro and in vivo. In particular, the intimal temperature was significantly lower (P < 0.05) for the diode than for the Nd:YAG repairs (approximately 35 degrees C and approximately 50 degrees C, respectively). In the latter group, the patency rate was 75%, but thrombosis occurred in 75% of the specimens at 21 days. All diode anastomoses were patent and thrombosis developed in only 17% of the arteries. CONCLUSION: Use of the diode laser and albumin solders may provide a means to successfully repair carotid arteries with minimal thermal damage.

Self-expandable chitosan stent: design and preparation.

Stents are largely used in surgical procedures to relieve pathological obstructions. The purpose of the present study was to design and prepare a biocompatible stent with a self-expandable mechanism. Thin films were prepared from deacetylated chitosan (4% w/v) dissolved in acetic acid solution (2% v/v). The chitosan films were tested by a calibrated tensiometer to measure the Young's module (E). The films were used to manufacture stents by pulling and winding them around a cylindrical rod in a helical fashion. Thirteen stents (diameter = 0.5 +/- 0.05 mm, length approximately 4 mm) were inserted into the vas deferens of wistar rats. Upon stent insertion, the vasal anastomosis was achieved with a laser-soldering technique. The animals were sacrificied 8 weeks later. The stress test showed that the chitosan film was elastic (maximum strain = 105% +/- 6%, E = 0.7655 +/- 0.0288 Mpa). The stents self-expanded by releasing their elastic energy. All the stents but one remained open inside the vasa despite high incidence of sperm granuloma. A biocompatible and self-expandable stent with a helical design is proposed.

Role of nitric oxide in renal tubular apoptosis of unilateral ureteral obstruction.

BACKGROUND: The obstructed kidney in unilateral ureteral obstruction (UUO) is characterized by renal atrophy and tissue loss, which is mediated by renal tubular apoptosis. We sought to determine whether NO is involved in renal tubular apoptosis in vitro and in vivo. METHODS: Rat renal tubular epithelial cells (NRK-52E) were subjected to mechanical stretch, and apoptosis and cell size were analyzed by flow cytometry. Furthermore, we studied UUO in mice lacking the gene for inducible nitric oxide synthase (iNOS-/-) and their wild-type littermates. Tubular apoptosis and proliferation were detected by immunostaining. NOS activity and NOS expression were assessed by a citrulline assay and Western blot, respectively. RESULTS: Stretching-induced apoptosis in NRK-52E, which was reduced when NO was increased; conversely, stretch-induced apoptosis was increased when a NOS inhibitor was added to the cells. Stretched cells are larger and more apoptotic than unstretched cells. In UUO, the obstructed kidney of iNOS-/- mice exhibited more apoptotic renal tubules than the wild-type mice through 14 days of UUO. The obstructed kidney of iNOS-/- mice at day 3 showed more proliferative tubules compared with wild type. The obstructed kidney of wild-type mice exhibited higher total NOS activity until day 7 after UUO compared with iNOS-/- mice. However, the obstructed kidney of day 14 wild-type mice exhibited significantly lower iNOS activity and protein compared with the day 0 kidney. CONCLUSION: These results suggest that mechanical stretch is related to renal tubular apoptosis and that NO plays a protective role in this system in UUO.

Mechanism of healing following the Snodgrass repair.

PURPOSE: It has been suggested that healing after tubularized incised plate urethroplasty occurs through re-epithelialization with normal tissue ingrowth or by secondary intent through scarring. We investigated healing in tubularized incised plate urethroplasty. MATERIALS AND METHODS: Hypospadias was created in 5 dogs by incising the ventral urethra, allowed to heal for 21 days and subsequently repaired. During hypospadias creation a tattoo was made longitudinally in the midline dorsal urethral plate. The tattoo was bisected during repair, thus creating 2 distinct lines marking the edges of the incision. A neourethra was tubularized and closed in 2 layers. At 21 days the phallus was harvested, inspected and embedded for histology. RESULTS: The dorsal urethral plate incision contained 2 distinct lines in all samples representing the area of separation between the native and ingrowing urethras. The distance between these lines was 0.9 +/- 0.1 mm. Proximal urethral lumen diameter (3. 3 +/- 0.1 mm.) was not significantly different from that of the neourethral lumen (3.1 +/- 0.1 mm.). Histologically all repairs had intact squamous epithelium. There was normal appearing subepithelial architecture with scant perivascular lymphocytic infiltrates between the tattoos. In contrast, the area around the sutures showed a desmoplastic (fibroblastic) reaction with an inflammatory, primarily neutrophilic response. CONCLUSIONS: Healing of the incision in the dorsal urethral plate during tubularized incised plate urethroplasty occurs by re-epithelialization with normal tissue ingrowth. In contrast, the sutured closure heals with a desmoplastic and inflammatory response.

Differential scanning calorimetry of albumin solders: interspecies differences and fatty acid binding effects on protein denaturation.

BACKGROUND AND OBJECTIVE: Understanding albumin solder denaturation is important for laser tissue soldering. Human (HSA), bovine (BSA), porcine (PSA), and canine (CSA) albumin both fatty acid containing (FAC) and fatty acid free (FAF) were evaluated by using differential scanning calorimetry (DSC). STUDY DESIGN/MATERIALS AND METHODS: DSC was used to measure difference thermograms to determine the irreversible thermal denaturation profile for 50% albumin solutions. The denaturation transition's onset, end and peak temperatures, and enthalpy were measured. RESULTS: All FAC species, except BSA, exhibited twin peaked endotherms. Single endotherms were observed for all FAF species and BSA-FAC. Onset and end temperatures were significantly [P < 0.001] lower for all FAF species (except BSA's end temperature). There was a 30% decrease in the denaturation enthalpy between FAF and FAC groups. CONCLUSION: FAF albumin solders were found to denature at significantly lower temperatures, while also having a 30% reduction in enthalpy when compared with their FAC counterparts.

Antibody to transforming growth factor-beta ameliorates tubular apoptosis in unilateral ureteral obstruction.

BACKGROUND: Unilateral ureteral obstruction (UUO) is characterized by progressive renal atrophy, renal interstitial fibrosis, an increase in renal transforming growth factor-beta (TGF-beta), and renal tubular apoptosis. The present study was undertaken to determine the effect of a monoclonal antibody to TGF-beta (1D11) in UUO. METHODS: Mechanical stretch was applied to tubular epithelial cells (NRK-52E) by a computer-assisted system. Three doses of 1D11 (either 0.5, 2, or 4 mg/rat) were administered to rats one day prior to UUO and every two days thereafter, and kidneys were harvested at day 13. Fibrosis was assessed by measuring tissue hydroxyproline and mRNA for collagen and fibronectin. Apoptosis was assessed with the terminal deoxy transferase uridine triphosphate nick end-labeling assay. TGF-beta levels were determined by bioassay. Western blot and immunostaining were used to identify proliferating cell nuclear antigen (PCNA), p53, bcl-2, and inducible nitric oxide synthase (iNOS). RESULTS: Stretch significantly induced apoptosis in NRK-52E cells, which was accompanied by an increased release of TGF-beta; 1D11 (10 microg/mL) totally inhibited stretch-induced apoptosis. Control obstructed kidney contained 20-fold higher TGF-beta as compared with its unobstructed kidney; 1D11 neutralized tissue TGF-beta of the obstructed kidney. Control obstructed kidney exhibited significantly more fibrosis and tubular apoptosis than its unobstructed counterpart, which was blunted by 1D11. In contrast, 1D11 significantly increased tubular proliferation. p53 immunostaining was localized to renal tubular nuclei of control obstructed kidney and was diminished by 1D11. In contrast, bcl-2 was up-regulated in the 1D11-treated obstructed kidney. Total NOS activity and iNOS activity of the obstructed kidney were increased by 1D11 treatment. CONCLUSION: The present study strongly suggests that an antibody to TGF-beta is a promising agent to prevent renal tubular fibrosis and apoptosis in UUO.

Interstitial fibrosis of unilateral ureteral obstruction is exacerbated in kidneys of mice lacking the gene for inducible nitric oxide synthase.

Unilateral ureteral obstruction (UUO) is characterized by decreases in renal function and increases in interstitial fibrosis. Previous studies have indicated that pharmacologic manipulations that increase nitric oxide (NO) are beneficial to the obstructed kidneys. NO is produced from arginine by nitric oxide synthase (NOS), an enzyme that exists in both constitutive and inducible (iNOS) forms. To determine the role of the inducible form of NOS in UUO, we used mice with a targeted deletion of iNOS (iNOS -/- mice) and compared them with wild-type (WT) mice. Kidneys were obstructed for 2 weeks in both WT and iNOS -/- mice, and were then removed and bisected. Half of the kidney was embedded in paraffin and tissue sections were examined for interstitial volume or the presence of macrophages. The remainder was flash-frozen and samples were used to measure tissue collagen (hydroxyproline) or transforming growth factor-beta (TGF-beta). This study demonstrates that both cortex and medulla of obstructed kidneys of iNOS -/- mice exhibit significantly increased interstitial volume and interstitial macrophages as compared with their WT counterparts. Furthermore tissue collagen was increased to 9.2+/-1.3 microg/mg tissue in WT obstructed kidneys, whereas in iNOS -/- kidneys, collagen was increased to 13.2+/-0.8 microg/mg tissue. The profibrotic cytokine TGF-beta was also significantly increased in obstructed kidneys of iNOS -/- mice, as compared with WT mice. No differences were noted between the unobstructed kidneys of iNOS -/- mice compared with WT mice in any of the parameters examined. These results demonstrate that targeted deletion of the iNOS results in exacerbation of fibrotic events in the obstructed kidney. These results confirm previous pharmacologic studies, and suggest that NO produced via the inducible NOS normally serves a protective function in UUO.

Interaction of nitric oxide and transforming growth factor-beta1 induced by angiotensin II and mechanical stretch in rat renal tubular epithelial cells.

PURPOSE: Changes in intrarenal pressure accompanying unilateral ureteral obstruction can result in tubular mechanical stretch and mediator release from renal tubules. Therefore, we examined the synthesis of nitric oxide and transforming growth factor-beta (TGF-beta), and their interaction in rat renal epithelial cells (NRK-52E) exposed to either angiotensin II or mechanical stretch. MATERIALS AND METHODS: NRK-52E were exposed to either angiotensin II or mechanical stretch. Nitrite and TGF-beta in the supernatant were assessed by the Greiss reaction and bioassay, respectively. The level of cell hypertrophy and intracellular TGF-beta protein was determined by flow cytometry. TGF-beta messenger RNA and inducible nitric oxide synthase protein were detected by reverse transcriptase polymerase chain reaction and Western blot, respectively. RESULTS: Angiotensin II stimulated TGF-beta1 and nitric oxide. The nitric oxide synthase inhibitor, N-nitro-L-arginine (L-NAME) or angiotensin II type I receptor blocker, losartan, inhibited nitric oxide and TGF-beta1 induced by angiotensin II. Flow cytometry showed that either L-NAME or losartan inhibited angiotensin II induced cell hypertrophy. TGF-beta1 inhibited iNOS protein and nitric oxide, whereas an anti-TGF-beta antibody enhanced iNOS. Mechanical stretch induced TGF-beta, inducible NOS protein and nitric oxide. However, TGF-beta expression was not affected by L-arginine or L-NAME when cells were exposed to mechanical stretch. CONCLUSIONS: These results demonstrate that nitric oxide is an intermediate in angiotensin II stimulated TGF-beta1 expression but not in stretch induced TGF-beta expression, and that TGF-beta1 is a negative regulator of nitric oxide in rat renal epithelial cells. The complex interaction of these cytokines may be a target for intervention in the fibrotic and apoptotic processes in the obstructed kidney.

Semi-solid albumin solder improved mechanical properties for laser tissue welding.

BACKGROUND AND OBJECTIVE: A semi-solid albumin solder formulated with hydroxypropylmethylcellulose (HPMC) was designed to improve the characteristics of liquid and solid solders. STUDY DESIGN/MATERIALS AND METHODS: Acute tensile strengths were determined on canine small bowel in vitro by using liquid 50% bovine serum albumin (BSA), semi-solid 48% BSA with HPMC, and solid 60% BSA solder. Long-term healing of liquid and semi-solid solders, compared with a suture control, was evaluated in a porcine skin model, with tensile strength as well as histologic findings obtained on postoperative day 7. RESULTS: Acutely, semi-solid solder demonstrated a significantly (P < 0.05) higher tensile strength when compared with liquid or solid solder. At 7 days, HSA semi-solid and BSA semi-solid had significantly (P < 0.05) higher tensile strength than suture control; however, no differences were seen for liquid or solid solder groups. No differences in histology were appreciable between any of the solder groups in a porcine skin model. CONCLUSION: Acutely and at 7 days, semi-solid solder was stronger than 50% liquid albumin with better handling characteristics.

Welding characteristics of different albumin species with and without fatty acids.

BACKGROUND AND OBJECTIVE: Albumin solders from different species have been used for laser tissue welding without a complete understanding of possible differences between them. The breaking strength of four different species of serum albumin (human, bovine, porcine, and canine), both fatty acid containing (FAC) and fatty acid free (FAF), was determined to evaluate the welding ability of each type of albumin. STUYDY DESIGN/MATERIALS AND METHODS: Acute breaking strengths were determined on canine small bowel by using 50% albumin (FAF and FAC) from human, bovine (BSA), porcine, and canine species. RESULTS: BSA-FAC and BSA-FAF had a significantly higher (P < 0.05) breaking strength than all other groups; furthermore, BSA-FAC was significantly higher (P < 0.05) than BSA-FAF. There was no significant difference in breaking strength when FAF albumin was compared with FAC albumin from humans, pigs, or dogs. CONCLUSION: These experimental results show that species-specific and fatty acid-specific differences exist when these albumin solders are used for laser tissue welding. This finding suggests that modifications in albumin could be used to improve results through decreased thermal damage and increased weld strength.

Effect of aging on bladder function and the response to outlet obstruction in female rats.

Bladder dysfunction in the aging population is a significant problem. However the concomitant presence of other diseases in many patients can make it difficult to distinguish between changes in bladder function and other influences. The present study was designed to study, in aging rats, bladder function and the effect of partial bladder outlet obstruction (BOO) on bladder function. Cystometrics were performed in awake, female Fischer 344 rats of four age groups (6, 12, 18 and 24 months) following subcutaneous implantation of a mediport catheter. Cystometric evaluations were carried out in control rats or those subject to three weeks of BOO. Bladder compliance significantly decreased with aging, which reflected an increase in threshold pressure without changes in bladder capacity. Partial BOO caused development of severe bladder instability. Following BOO, bladder capacity and compliance were significantly increased in all age groups. Threshold pressure was lower in obstructed animals, except for 6-month rats. Younger animals were able to generate a higher contraction pressure to compensate for the BOO, whereas older animals did not. Using an awake model of cystometric measurement, we have demonstrated that aging, by itself can affect bladder function. Furthermore, aged animals respond differently to BOO than younger animals. These results demonstrate that both aging and disease can contribute to bladder dysfunction, and suggest that treatment of bladder dysfunction may require a combination of therapies targeted to multiple etiologies.

Laser-assisted demucosalized gastrocystoplasty with autoaugmentation in a canine model.

OBJECTIVES: Laser-assisted autoaugmentation gastrocystoplasty has been performed successfully. Experiments were performed to determine the optimal laser for tissue welding during demucosalized autoaugmentation gastrocystoplasty using both a 1.9-microm diode and a 1.32-microm neodymium:yttrium-aluminum-garnet (Nd:YAG) laser with and without thermal control. METHODS: Autoaugmentation gastrocystoplasty was performed on 18 female mongrel dogs. Anastomoses were performed by either suture or laser welding with a 50% human albumin solution. A 1.9-microm diode laser was compared with a 1.32-microm Nd:YAG laser with and without thermal control. In vivo canine bladder capacity measurements were performed both before gastrocystoplasty and at euthanasia. The animals were studied on days 4 and 14. Samples of the anastomotic area from each group were taken to measure tensile strength. Histologic samples were assessed for tissue damage. RESULTS: There was a significant increase in bladder volume in the 4-day group compared with pregastrocystoplasty values. Both the 1.9-microm diode laser and suture control dogs with the 14-day repairs had significantly more tensile strength than their 4-day counterparts. In contrast, no statistical difference was found between the 4 and 14-day 1.32-microm Nd:YAG groups. The suture control group had evidence of minor tissue devitalization at the anastomosis at both 4 and 14 days. The 1.9 and 1.32-microm laser groups both had evidence of tissue devitalization at 4 and 14 days. The 1.32-microm laser group had primarily severe tissue injury. The laser groups at 14 days demonstrated an inflammatory reaction that was localized to the albumin. CONCLUSIONS: Demucosalized gastrocystoplasty with autoaugmentation can be safely and successfully performed with a 1.9-microm diode laser without significant differences in tensile strength when compared with suture controls. The 1.32-microm Nd:YAG laser can also be successfully used; however, the long-term results appear to be inferior to the 1.9-microm diode laser.

Assessment of the degradation of denatured albumin solder by human urine.

PURPOSE: Several studies have been undertaken to evaluate the efficacy of human serum albumin (HSA) as a solder in urologic procedures. The purpose of this study was to evaluate whether albumin solder undergoes significant degradation in urine. MATERIALS AND METHODS: Laser denatured 25% HSA pellets were incubated at 37C for varying times with 1 ml. of either pooled human urine or control diluent solution adjusted to the same pH and osmolality as urine. To assess the contribution of enzymatic degradation, aliquots of urine were boiled and compared with non-boiled urine and diluent. The amount of solubilized HSA in solution was measured using the Bradford assay, while the degradation of albumin was detected by SDS-PAGE electrophoresis. RESULTS: Approximately 5% of the albumin was degraded over a period of 7 days following incubation at 37C, regardless of treatment. SDS-PAGE revealed only minor traces of degradation in urine and controls. The very slight degradation of denatured HSA appears to be non-enzymatic, as it was observed in both urine and diluent samples. CONCLUSIONS: HSA solder appears to be appropriate for use in urologic reconstructive surgery since it is not appreciably degraded in the presence of urine.

Effect of laser welding with human serum albumin on the expression of P-selectin on platelets.

BACKGROUND AND OBJECTIVE: Artery repair by means of laser energy induces activation of platelets with a risk of thrombosis and local inflammatory reactions. The aim of this study was to investigate the effect of human serum albumin, the most common solder in laser surgery, on platelet activation. STUDY DESIGN/MATERIALS AND METHODS: Platelet activation was evaluated in canine blood by using two-color flow cytometry with a phycoerythrin-labeled antibody to a common platelet marker, glycoprotein IIb/IIIa and fluorescein isothiocyanate-labeled antibody to a platelet activation molecule, P-selectin. Human serum albumin was applied in vitro and in vivo, as a solder during laser reconstruction of canine arteries. RESULTS: In vitro, albumin significantly (P < 0.01) reduces the expression of P-selectin on platelets. This is most likely related to the blockage of P-selectin by albumin, which binds to the platelet surface, as confirmed by flow cytometry with fluorescein isothiocyanate-labeled albumin. In vivo, application of albumin solder tended to result in a lower percentage of P-selectin-expressing platelets in laser-repaired arteries compared to suture-repaired arteries. CONCLUSION: Albumin decreases the percentage of P-selectin-expressing platelets in vitro. Further research may allow the platelet activation inhibiting properties of albumin to be further optimized in vivo.