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Biomedical subjects

Roman Jednak

Publications and source records attributed to Roman Jednak.

6 recordsLinked to original sources

PAX2 is reactivated in urinary tract obstruction and partially protects collecting duct cells from programmed cell death.

Obstruction of the urinary tract activates apoptotic pathways in collecting duct cells and leads to loss of renal parenchyma before surgical intervention. It has been suggested that developmental pathways may be reactivated to offset acute organ damage. One such molecule, PAX2, is expressed throughout the fetal collecting duct and was recently shown to suppress apoptosis during kidney development. We hypothesized that acute unilateral urinary tract obstruction (UUO) reactivates PAX2 expression in the mature kidney and partially suppresses apoptosis. If so, animals with PAX2 mutations should have increased susceptibility to parenchymal damage. Wild-type and heterozygous Pax2 mutant (C3H/Pax2(1Neu)) mice underwent unilateral ureteric ligation or sham operation at 6 wk of age; kidneys were examined after 5, 10, and 15 days. Whereas PAX2 protein levels fell to low levels in the first weeks of life, it was sharply reactivated by day 10 in collecting duct cells of wild-type but not in Pax2(1Neu) mutant mice with UUO. Wild-type mice with UUO had marked TUNEL and cleaved spectrin staining in tubular cells and reduced kidney weight after 10-15 days. Mutant mice had exaggerated increases in markers of apoptosis and exaggerated loss of renal parenchymal loss in the obstructed kidney. These observations suggest that PAX2 is rapidly reactivated in UUO and that mice with genetically limited PAX2 expression have heightened susceptibility to apoptosis.

Animals↗

Mucocolpos associated with bladder exstrophy: a case report.

INTRODUCTION: We present the first reported case demonstrating an association of mucocolpos and bladder exstrophy. MATERIALS: A term baby girl presented with bladder exstrophy and underwent a successful primary bladder closure and ureteral reimplantation. Subsequently, she presented with a fluid-filled pelvic mass which was found to be a mucocolpos. RESULTS: Surgical drainage of the collection was required. CONCLUSION: Mucocolpos should be considered in the differential diagnosis of a pelvic mass in a patient with bladder exstrophy.

Bladder Exstrophy↗

Should warm infusion solution be used for urodynamic studies in children? A prospective randomized study.

PURPOSE: We hypothesized that warm infusion solution should be used for urodynamic studies in children because it more closely simulates normal physiology. Thus, we conducted a prospective randomized study comparing consecutive room temperature (RT) and body temperature (BT) cystometrograms (CMG) in the same child. MATERIALS AND METHODS: Subjects underwent identical CMGs using RT and BT saline in random order. Maximum cystometric bladder capacity (CBC), pressure at CBC, uninhibited detrusor contractions, detrusor leak point pressure, maximum flow rate, pressure at maximum flow, maximum voiding pressure, residual urine and pressure specific volumes below 20 and 30 cm water were compared. Data were analyzed using ANOVA, t test, and chi-square. RESULTS: RT and BT CMGs in 44 males and 47 females with a mean age of 8.6 years were compared. Of the children 58 (64%) had spinal dysraphism, 8 (9%) had cerebral palsy, 5 (6%) had posterior urethral valves and 20 (21%) had recurrent urinary tract infection, daytime incontinence or frequency/urgency symptoms. Maximum CBC, pressure at CBC, and pressure specific volumes below 20 and 30 cm water were significantly lower (10% to 15%) during BT cystometry. Maximum flow rate was higher with BT saline. Detrusor leak point pressure, pressure at maximum flow, maximum voiding pressure, and residual urine did not differ. Uninhibited detrusor contractions were more frequent during RT infusions. No gender differences were found. The discrepancies between RT and BT cystometry were most prominent in infants, children with spinal dysraphism and children with large bladders. CONCLUSIONS: There is a difference between cystometries performed using RT and BT saline. Capacity, storage variables and detrusor activity are diminished during BT cystometry. Although statistically significant differences were found between consecutive RT and BT CMGs, the magnitude of the difference may not be clinically relevant to change management. As such, we do not believe it is necessary to use warm infusion solution on a systematic basis for urodynamic studies in children. However, for children younger than 2 years when the magnitude was more relevant, the use of warm solution is recommended.

Body Temperature↗

A modified access technique for retroperitoneoscopic renal surgery in children.

PURPOSE: Present techniques for retroperitoneal endoscopic (RPE) access in children mimic those in adults but often result in peritoneal entry or gas leaks, both of which lead to a decrease in the retroperitoneal space. We describe a modification to the access technique that obviates these problems, thus, facilitating RPE in children. MATERIALS AND METHODS: In the lateral decubitus position the initial port is placed immediately lateral to the paraspinal muscles, similar to open dorsal lumbotomy fascial incision. A 5 mm skin incision is made at the level of the costovertebral angle and an artery forceps used to tunnel bluntly past the lumbodorsal fascia. A 5 mm port is placed with a blunt trocar, and expansion of the retroperitoneal space performed with the telescope and gas insufflation. Ancillary ports are placed and the telescope then moved to an anterior subcostal port where popular RPE approaches place the initial port. RESULTS: Eighteen procedures were performed in children with a mean age of 10.8 years, including 12 nephrectomies, 3 dismembered pyeloplasties, 1 partial nephrectomy, 1 nephroureterectomy and 1 parapelvic cyst decortication. No gas leaks occurred, with 1 minor peritoneal entry early in the series not related to the access. Average surgical time for nephrectomy was 178 minutes (range 120 to 240). No intraoperative complications occurred. CONCLUSIONS: We present a safe and effective technique of initial port placement that follows the principles of open lumbotomy exposure. This approach to RPE minimizes peritoneal entry and gas leaks, thus, maximizing surgical exposure.

Adolescent↗