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Biomedical subjects

M E Mitchell

Publications and source records attributed to M E Mitchell.

At least 55 records · Page 3Linked to original sources
PubMed1997

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.

Animals↗
PubMed1997

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.

Humans↗
PubMed1996

Continent gastric pouch.

Between January 1985 and June 1995 a total of 12 patients (9 female, 3 male) underwent total reconstruction of the lower urinary tract using gastric tissue. Their mean age was 10 years (range, 5-25 years). Total gastric bladder substitution was performed in seven patients, whereas five other patients had composite continent reservoirs (stomach plus bowel) created. The diagnoses were cloacal exstrophy, classic bladder exstrophy, bladder rhabdomyosarcoma, bilateral ectopic ureters, and VACTERL association. The mean follow-up period was 4.5 years (range, 16 months to 9 years). The average bladder capacity was 309 ml, and the compliance averaged 12.9 ml/cmH2O. Continence was achieved in all patients, but the continence mechanism often required revision. Renal deterioration was noted only in one patient due to an obstruction at the site of a transureteroureterostomy. The complications included hyponatremic, hypochloremic metabolic alkalosis (two patients); prolapse of the neovagina (one patient); a ureterovesical junction obstruction (three patients); and revision of the neourethra or Mitrofanoff (six patients). Revision of the gastric tube used as the catheterizable channel was performed in three instances. Lengthening of the tube, including nippling in one instance, corrected persistent incontinence. Distal stenosis of a gastric tube required several plastic procedures for correction. A ureteral Mitrofanoff developed a distal stricture necessitating revision. Persistent leaking of an appendiceal Mitrofanoff was corrected with reimplantation. A tapered ileal neourethra required a tunneling procedure followed by Teflon injection to provide urinary continence. Complications seen most often involved the continence mechanism of these gastric neobladders or composite urinary reservoirs. Persistence, patience, and perseverance led to total urinary continence and adequate reservoirs for urine storage in all patients.

Adolescent↗
PubMed1996

Endourologic removal of upper airway foreign objects: case report.

The authors report on removal of upper airway foreign bodies using endourology baskets and stone graspers in a patient who did not respond to standard upper airway management. The procedure was safe and effective with localization and successful removal of most of the stone burden.

Bronchi↗
PubMed1996

Five primary synchronous neoplasms of the gastrointestinal tract.

Multiple primary malignant neoplasms in a single patient have been well documented in the literature over the past hundred years. The lesions can be limited to a single organ or involve multiple organ systems. It is relatively common for patients with colorectal carcinoma or carcinoid tumors to have more than one primary neoplasm. Colonic lesions can be synchronous or metachronous in presentation and colonic or extracolonic in location. We present a patient with five primary synchronous neoplasms of the gastrointestinal tract, involving the stomach, small bowel, and colon. The patient had no evidence of metastatic disease and underwent resection of all the lesions. This case illustrates the need for a thorough search for additional neoplasms in the treatment of patients with cancer.

Adenocarcinoma↗
PubMed1996

Developmental regulation of collagen differential expression in the rabbit bladder.

PURPOSE: It has been suggested that the amount and relative ratios of different types of collagen influence bladder compliance. To understand the mechanisms regulating collagen synthesis and degradation in the bladder we investigated the gene expression of collagen types I and III in the rabbit bladder during normal development. MATERIALS AND METHODS: New Zealand white rabbits ages fetus to adult were used for this study. The mid portion of the bladder wall was harvested. Northern blot hybridization was performed to analyze quantitatively collagen types I and III messenger (m) ribonucleic acid (RNA), and in situ hybridization was done to localize the messages. Corresponding protein distributions were obtained by immunohistochemical staining. RESULTS: Types I and III collagen are developmentally regulated at the level of gene expression. The temporal and spatial distribution of the mRNA transcripts of alpha 1(I) and alpha 1(III) correlates with extracellular protein deposition. Differential distribution of the mRNA transcripts is also developmentally regulated. CONCLUSIONS: This study characterizes the relationship between collagen gene expression and normal rabbit bladder development. The expression of alpha 1(I) and alpha 1(III) alters as the bladder grows. High levels and nonconcordant up and down regulation of different types of collagen mRNA during early development demonstrate the complexity of the extracellular matrix in a young bladder. This observation may be important in our understanding of the injury response in a developing versus mature bladder.

Animals↗
PubMed1996

Collagen types I and III localization by in situ hybridization and immunohistochemistry in the partially obstructed young rabbit bladder.

PURPOSE: The objective of the study was to investigate the alteration of collagen expression patterns at the transcription and translation levels during partial outlet obstruction and to compare changes in collagen types I and III gene expression, and protein deposition during early and subacute phases of obstruction. MATERIALS AND METHODS: Following 1, 2, 7, 14 and 21 days of partial bladder obstruction in 2-week-old rabbits bladder tissues were evaluated for collagen types I and III messenger ribonucleic acid localization by in situ hybridization and for protein localization by immunohistochemical study. RESULTS: There is up regulation of collagen types I and III gene expression after obstruction. Up regulation of collagen gene expression immediately after obstruction is within the lamina propria and the message moves into the muscular layer as obstruction progresses. Protein deposition for both collagen types is analogous to that of gene expression. CONCLUSIONS: Up regulation of collagen types I and III gene expression, and increased protein deposition after partial obstruction demonstrate that the alteration in collagen synthesis is at least partially transcription regulated. This alteration starts from superficial layers of the bladder wall and becomes deeper as the pathological process progresses.

Age Factors↗
PubMed1996

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.

Adolescent↗
PubMed1996

Complete penile disassembly for epispadias repair: the Mitchell technique.

PURPOSE: We report a new technique for epispadias repair, which relies on the unique blood supply of the corpus cavernosum and glans. The epispadiac phallus is completely disassembled into 3 discrete components: the urethral plate, and the right and left hemicorporeal glandular bodies. MATERIALS AND METHODS: Ten boys 10 months to 17 years old presented for repair of epispadias between 1990 and 1994 (6 primary and 4 secondary repair). One patient underwent bladder exstrophy closure at the time of epispadias surgery. Two patients underwent prior para-exstrophy flap procedures and neither had fistulas. RESULTS: Followup (8 to 57 months) revealed a conical glans in 8 patients, straight shaft upward in 1 and ventral orthotopic meatus in 7. In 2 patients who underwent secondary repair 3 fistulas formed that were repaired on an outpatient basis. All patients are potent. CONCLUSIONS: Complete disassembly allows tubularization and ventralization of the entire distal urethra; makes glans and urethral repair independent; separates the 2 corporeal glandular bodies, permitting easier and more complete release of the rotation contributing to dorsal chordee, and improves exposure for corporotomy or dermal grafts.

Adolescent↗
PubMed1996

Demucosalized augmentation gastrocystoplasty with bladder autoaugmentation in pediatric patients.

PURPOSE: Potential metabolic complications in urinary reconstruction with bowel or stomach are due to the presence of the gastrointestinal mucosal layer. The advantage or disadvantage of each tissue has been debated. We report a procedure in which the mucosa of a gastric pedicle flap is removed and the remaining muscularis flap is transferred to an autoaugmented bladder. MATERIALS AND METHODS: Seven female and 4 male patients underwent the procedure at our institutions from October 1992 to November 1994. A retrospective chart review was performed to compare preoperative to postoperative urodynamic findings, continence status and complications. RESULTS: Mean followup was 23 months (range 8 to 33). Preoperative urodynamics showed an average bladder capacity of 109 cc (range 45 to 200) and compliance of 3 ml./cm. water (range 1 to 6). Urinary continence was achieved in 10 patients on clean intermittent catherization every 3 to 4 hours and 1 was wet due to low urethral resistance. All patients underwent postoperative urodynamics. Bladder capacity increased to 236 cc (range 150 to 300) with an average compliance of 9 ml./cm. water (range 5 to 14). No metabolic complications were noted. CONCLUSIONS: The gastric muscularis appears to be preserved along with the native urothelium to provide a compliant tissue that can be an alternative to bowel and stomach for bladder augmentation. Because the procedure involves demucosalizing the gastric patch as well as performing bladder autoaugmentation, operative time is increased compared to normal gastrocystoplasty or enterocystoplasty. However, the lack of metabolic complications and mucus-free urine are important considerations and substantial advantages.

Adolescent↗
PubMed1996

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.

Follow-Up Studies↗
PubMed1995

Pseudoureterocele: potential for misdiagnosis of an ectopic ureter as a ureterocele.

OBJECTIVE: To present several case reports of children with 'pseudoureteroceles'. Familiarization with this entity should help to avoid an error in diagnosis and possible improper therapy. PATIENTS AND METHODS: Three girls with ectopic ureters entering mesonephric duct cysts are presented for review. RESULTS: Misdiagnosis of the pseudoureterocele as an ectopic ureter was made in two children. The 'pseudoureterocele' may lie dormant for many years and often presents with acute urinary incontinence and/or onset of urinary tract infections. Resection of the dysplastic kidney and ipsilateral ureter, marsupialization of the cyst into the vagina, and closure of the vesical fistula is the preferred treatment. CONCLUSION: An ectopic ureter draining into a Gartner's duct cyst can be confused with an ectopic ureterocele. Correct diagnosis is vital to ensure proper treatment.

Adolescent↗
PubMed1995

The Mitrofanoff catheterizable channel: patient acceptance.

A review of our experience with the Mitrofanoff catheterizable channel, with emphasis on patient acceptance and preference, is presented. Continent catheterizable channels using the Mitrofanoff principle were created in 35 patients (mean age 9.1 years, range 2 to 21). Mean followup was 22 months (range 1 to 60). Followup data are available for 33 patients. We used the appendix, ureter, fallopian tube and tube of stomach to construct the channel. All 33 patients used the Mitrofanoff catheterizable channel without difficulty for at least 3 months postoperatively. A total of 16 patients (48%) can empty the bladder only by Mitrofanoff catheterization and do so without difficulty. All 11 patients (33%) who have the potential to catheterize either the Mitrofanoff channel or urethra choose to catheterize the Mitrofanoff channel preferentially. The patient not using Mitrofanoff catheterization had stomal stenosis 12 months postoperatively and elected to perform urethral catheterization rather than undergo surgical repair. Five patients (15%) can void but all use the Mitrofanoff catheterizable channel to monitor post-void residual volumes. This study shows a high acceptance rate for patients receiving a continent catheterizable stoma.

Adolescent↗
PubMed1994

Development of a coding system for marital problem solving efficacy.

Efficacy in marital problem solving has received little attention, and work on general problem solving efficacy does not address marital issues. This study examined the ability to discriminate between groups and criterion validity of an efficacy-focused marital problem solving measurement method, the Marital Efficacy Coding System, which combines marital problem scenarios with general social problem solving assessment procedures. This system was administered to nondistressed married subjects, participants in marital therapy, and divorced or separated individuals. Participants were asked to develop a set of discrete steps or 'means' as solutions to marital problem scenarios. The content was coded by a number of means, participants' ratings of problem frequency and typicality of response, and coders' ratings of efficacy and equality. Overall percentage agreement between coders was 73.4%. Marital Efficacy Coding System variables, including problem frequency, solution typicality, and solution efficacy, were shown to significantly differentiate between participants high and low in marital satisfaction and to possess significant predictive ability.

Adult↗
PubMed1994

Renal transplantation into the dysfunctional bladder: the role of adjunctive bladder reconstruction.

A retrospective review of pediatric renal transplantation at 3 centers identified 9 patients who had undergone major bladder reconstruction. Seven patients underwent bladder augmentation (5 gastric, 1 colonic, 1 ureteral) and 2 received gastric neobladders. Six patients required Mitrofanoff neourethras. Patient survival was 100% with initial graft survival of 56% during a mean followup of 29.4 months. Eight patients (89%) are presently dialysis-free with functioning allografts and all 9 (100%) are continent of urine. We conclude that renal transplantation and reconstruction to ensure continence are justifiable in even the most anatomically compromised children with end stage renal disease. It is essential that the pediatric urologist should have an integral role in the management of such cases.

Adult↗
PubMed1994

Reconstruction of the umbilicus in exstrophy.

Reconstruction of the umbilicus has cosmetic and functional value in the surgical treatment of the child with bladder exstrophy. We report on 12 patients who underwent creation of a neoumbilicus as part of genitourinary reconstruction.

Adolescent↗
PubMed1994

Gastrocystoplasty in children.

The use of stomach for bladder reconstruction is an important tool for the urologic surgeon. Just as one would not perform hypospadias repair knowing only one technique, one should not consider bladder reconstruction with only one option for augmentation available. The advantages, disadvantages and a brief overview of our operative technique are presented. We have been very pleased with our experience with the use of stomach in the appropriate clinical situation.

Child↗