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Douglas A Canning

Publications and source records attributed to Douglas A Canning.

At least 19 recordsLinked to original sources
PubMed2006

Activation of the calcineurin pathway is associated with detrusor decompensation: a potential therapeutic target.

PURPOSE: We hypothesized that the calcineurin pathway mediated some of the complex remodeling process that allows a bladder subjected to partial outlet obstruction to adapt to its new workload. Atrial natriuretic factor mRNA expression served as a marker of calcineurin activation. MATERIALS AND METHODS: A total of 16 New Zealand White rabbits underwent surgical creation of partial outlet obstruction, followed by randomization to receive cyclosporin A (20 mg/kg intramuscularly twice daily) or no additional treatment for 14 days. Three animals underwent 2 weeks of partial bladder outlet obstruction followed by bladder biopsy and the reversal of obstruction. RESULTS: Atrial natriuretic factor expression was seen only in bladders with severe hypertrophy and it disappeared with the reversal of outlet obstruction. Cyclosporin A treatment resulted in a decrease in atrial natriuretic factor mRNA expression (p <0.05) and a marked shift in myosin heavy chain A-to-B ratios toward normal (p <0.01) and an increase in smooth muscle cross sectional area (p <0.05). Bladder mass decreased 40% but did not attain statistical significance (p = 0.08). CONCLUSIONS: The calcineurin pathway has a significant role in bladder wall hypertrophy following partial outlet obstruction. Bladder hypertrophy could not be fully prevented by cyclosporin A, suggesting that multiple signaling pathways are involved in this pathophysiology. The expression of myosin heavy chain AB isoforms is regulated in part by the calcineurin pathway.

Animals↗
PubMed2006

Urethral dilation as treatment for neurogenic bladder.

PURPOSE: We documented the change in bladder physiology and clinical outcomes after urethral dilation for managing neurogenic bladder. MATERIALS AND METHODS: Female patients with neurogenic bladder were identified who underwent urethral dilation due to failure to empty at low pressure or upper tract changes. Urethral dilation was performed using curved sounds to 36Fr (range 18Fr to 36Fr). Clinical charts were reviewed to document urodynamics, infection rates, symptomatology, vesicoureteral reflux and upper tract dilatation before and after dilation. RESULTS: A total of 19 children underwent urethral dilation a mean of 2 times. Mean age at first dilation was 19.3 months. Mean followup was 34.9 months. The indication for dilation was high detrusor leak point pressure in 16 children. The remaining children had recurrent infections (1), poor compliance (1) and bladder spasms (1). Clinical manifestations of increased detrusor leak point pressure in 16 children were vesicoureteral reflux in 11, upper tract dilatation in 9 and recurrent infections in 3. Long-standing improvement occurred in 12 of 16 patients with increased detrusor leak point pressure, in 0 of 1 with infection, in 0 of 1 with poor compliance and in 1 of 1 with bladder spasms. Overall improvement was noted in 13 of 19 cases (68%). Vesicoureteral reflux was identified in 14 of 19 patients. Improvement was seen in 6 of 14 cases, including complete resolution in 5 and improvement in 1. Hydronephrosis was seen in 11 of 19 patients with improvement in 7, including resolution in 1 and improvement in 6. Only 6 children required further surgical intervention, that is vesicostomy in 2 and reimplantation in 4. CONCLUSIONS: Urethral dilation is effective for lowering detrusor leak point pressure in children with neurogenic bladder and for improving upper tract dilatation and vesicoureteral reflux. This procedure may prevent the need for more complicated surgical intervention. It should be investigated further in well designed, prospective studies.

Child, Preschool↗
PubMed2006

Lower pole pelvi-ureteric junction obstruction in duplicated collecting systems.

OBJECTIVE: To determine the incidence and efficacy of treatment for pelvi-ureteric junction obstruction (PUJO, the most common cause of hydronephrosis in the fetal kidney) in duplicated systems. PATIENTS AND METHODS: We retrospectively assessed patients with PUJO in a duplex collecting system, reviewing each case for age, sex, anatomy, presenting symptoms and type of management. RESULTS: From 1994 to 2004, 1413 patients were identified to have hydronephrosis; 243 of them had pyeloplasty for PUJO, and five (2%) involved the lower pole of a duplicated collecting system. In two of the patients the presentation was prenatal hydronephrosis (mean age at diagnosis 6 weeks) and the remainder presented with flank pain and pyelonephritis (mean age 5 years); all were boys. There was only one incomplete duplication (Y type). Four patients had a dismembered pyeloplasty and one a ureteric calycostomy. Vesico-ureteric reflux was present in three patients and two required common sheath reimplantation. On a radioisotope scan during the follow-up (mean 12 months) the five patients showed an improvement and no evidence of functional obstruction. CONCLUSION: The incidence of PUJO in duplicated systems was 2%; treatment should be individualized and requires a careful preoperative evaluation. This anomaly appears to be more common in boys and in completely duplicated systems.

Child↗