Stephen A Zderic

The Children's Hospital of Philadelphia, Filadelfia, Pennsylvania, United States

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Publications (169)555.93 Total impact

  • Stephen A Zderic · Dana A Weiss ·
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    ABSTRACT: Objective: Imaging children with dysfunctional voiding remains a challenge because 98% of these children have normal anatomy. Identifying the 1-2% of children who do have an anatomic basis for incontinence is important; this article focuses on how pediatric urologists use imaging for the evaluation of patients with this condition. Conclusion: Imaging a patient with dysfunctional voiding can provide findings that will allow an accurate diagnosis and lead to optimal management. The key for the pediatric urologist is using imaging studies judiciously because the diagnostic yield is low. If every patient with dysfunctional voiding who presents to the clinic undergoes imaging, there will be little gain. Understanding in which patients to try imaging sooner versus trying medical and behavioral management first is a function of experience.
    American Journal of Roentgenology 10/2015; 205(5):W532-W541. DOI:10.2214/AJR.14.14019 · 2.73 Impact Factor
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    ABSTRACT: To study the pathophysiology of dysfunctional voiding, we have previously developed a model of stress-induced voiding dysfunction. We have shown that cyclosporine A (CsA), an inhibitor of the Ca(2+)-calmodulin complex, can prevent social stress-induced urinary retention. However, treatment with cyclosporine has not had an effect on the increase in the stress peptide corticotrophin-releasing factor (CRF) in Barrington's nucleus, which is involved in the micturition pathway. We now investigate whether cyclosporine administered after stress can reverse the abnormal voiding phenotype, and whether it has effects on the bladder wall itself, or on the stress response within Barrington's nucleus. Six-week old Swiss-Webster mice were exposed to aggressor males for 1 h a day, followed by 23 h of barrier separation. In a long-term trial, 1 month of stress was followed by single-cage housing for 6 months. In a separate CsA reversal trial, mice either received CsA in drinking water or had plain drinking water during 1 month of single-cage housing during recovery. Bladder contractile function was examined on a Guth myograph. Nuclear translocation of myocyte enhancing factor (MEF)-2 and NFAT (nuclear factor of activated T cells) in the bladder was assessed using electrophoretic mobility shift assays (EMSAs). The expression of CRF was determined in Barrington's nucleus using in situ hybridization. Voiding dysfunction persisted for up to 6 months after stress exposure while mice recovered in single-cage housing. In the CsA reversal trial, voiding patterns improved when they received CsA in water during single-cage housing following stress, whereas those that underwent single-cage housing alone had persistent abnormal voiding (Fig. A). There was no difference between CRF levels in Barrington's nucleus between reversal groups (p = 0.42) (Fig. B), possibly indicating a direct effect on the bladder rather than a persistent stress effect. There were no differences in the contractility of bladder wall muscle. CsA decreased the nuclear translocation of MEF-2 and NFAT induced by stress (Fig. C,D). CsA reverses stress-induced urinary retention, but does not change the stress-induced CRF increase in Barrington's nucleus. Furthermore, bladder smooth muscle contractility is unchanged by CsA; however, there are changes in the levels of the downstream transcription factors MEF-2 and NFAT. We suspect that additional CsA responsive neural changes play a pivotal role in the abnormal voiding phenotype following social stress. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.
    Journal of pediatric urology 05/2015; 11(4). DOI:10.1016/j.jpurol.2015.04.018 · 0.90 Impact Factor
  • Amanda Berry · Kristen Rudick · Meg Richter · Stephen Zderic ·
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    ABSTRACT: Results The primary referral diagnoses were day and night wetting in 37 (67%) and daytime incontinence in 18 (33%) children. A history of urinary tract infection (UTI) was noted in 32 (64%) patients, and 25% were maintained on antibiotic prophylaxis during the study period. Twenty-nine percent were maintained on anticholinergic medication. Patients attended an average of 2.5 biofeedback sessions. Voided volumes and post void residual volumes were unchanged, 50% of the abnormal uroflow curves normalized over the course of treatment (p < 0.05). Patient reported symptom score decreased from 12.8 ± 5.6 to 8.0 ± 6.5 (p < 0.002) over an average follow-up time of 276 days reflecting fewer daytime voiding symptoms. There was no significant change in the patient symptom score component for the night-time wetting. Patient-reported outcomes at the final session of biofeedback were rated an improved in 26 (47%), no change in 15 (27%), worse in three (5%) patients, and not rated in 11 patients (21%).
    Journal of Pediatric Urology 08/2014; 10(4). DOI:10.1016/j.jpurol.2014.06.003 · 0.90 Impact Factor
  • C. J. Long · S. Butler · J. Fesi · C. Frank · D.A. Canning · S.A. Zderic ·
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    ABSTRACT: Objective Social stress can suppress the voiding reflex, with resultant diminished voiding frequency and increased volumes. The calcineurin-NFAT (nuclear factor of activated T cells) pathway is important in memory development. It was hypothesized that interruption of the calcineurin-NFAT pathway might prevent social stress-induced voiding dysfunction. Methods Mice were subjected to social stress in an established resident-intruder model for one hour, followed by 23 hours of barrier separation. NFATc3, NFATc4 knockout (KO) and wild-type (WT) mice were studied. At two weeks, voiding patterns were collected; this was followed by sacrifice. Corticotropin-releasing factor (CRF) mRNA expression in Barrington's nucleus (BN) was determined by in-situ hybridization. Results Social stress decreased voiding frequency and increased voided volumes in WT strains. At baseline, NFATc3 KO mice showed decreased voids and increased volumes, while the NFATc4 KO mice resisted social stress. However, CRF mRNA increased in WT mice following social stress and was increased at baseline in NFATc3 KO mice. It was found that CRF mRNA did not increase following social stress in NFATc4 KO mice. The administration of CsA to WT mice normalized voiding patterns following social stress, albeit with no effect on CRF mRNA in BN. Conclusion Disrupting the calcineurin-NFAT axis by either genetic or pharmacologic approaches confers resistance to the development of social stress-induced voiding and dysfunction.
    Journal of Pediatric Urology 08/2014; 10(4). DOI:10.1016/j.jpurol.2014.04.002 · 0.90 Impact Factor
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    ABSTRACT: Partial bladder outlet obstruction (pBOO)-induced remodeling of bladder detrusor smooth muscle (DSM) is associated with the modulation of cell signals regulating contraction. We analyzed the DSM from obstructed murine urinary bladders for the temporal regulation of RhoA GTPase and Rho-activated kinase (ROCK), which are linked to Ca(2+)-sensitization. In addition, the effects of equibiaxial cell stretch, a condition thought to be associated with pBOO-induced bladder wall smooth muscle hypertrophy and voiding frequency, on the expression of RhoA, ROCK and CPI-17 were investigated. DSM from 1-, 3-, 7-, and 14-day obstructed male mice bladders and benign prostatic hyperplasia (BPH)-induced obstructed human bladders revealed over-expression of RhoA and ROCKβ at the mRNA and protein levels compared to control. Primary human bladder myocytes seeded onto type I collagen-coated elastic silicone membranes were subjected to cyclic equibiaxial stretch, mimicking the cellular mechanical stretch in the bladder in vivo and analyzed for the expression of RhoA, ROCKβ, and CPI-17. Stretch caused a significant increase of RhoA, ROCKβ, and CPI-17 expression. The stretch-induced increase in CPI-17 expression occurs at the transcriptional level and is associated with CPI-17 promoter binding by GATA-6 and NF-κB, the transcription factors responsible for CPI-17 gene transcription. Cell stretch caused by bladder over-distension in pBOO is the likely mechanism for initiating over-expression of the signaling proteins regulating DSM tone.
    AJP Cell Physiology 07/2014; 307(6). DOI:10.1152/ajpcell.00033.2014 · 3.78 Impact Factor
  • Matthew S Christman · Stephen A Zderic · Thomas F Kolon ·
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    ABSTRACT: We aimed to develop a conversion formula between different calculations for testicular volume asymmetry. Male adolescents with varicoceles who underwent scrotal ultrasound were studied. Two formulas were analyzed: (1) testicular volume differential, TVDiff = (RTV - LTV)/(TTV), and (2) atrophy index, AI = (RTV - LTV)/(RTV). RTV, LTV, and TTV represent the right, left, and total testicular volume. Through transformations and regression a conversion formula between the calculations was derived. Based on 248 ultrasounds, a clear relationship between the two formulas was demonstrated: AI = ln[(1.97 × TVDiff) + 1], (p < 0.0001). Differential testicular volumes can easily be converted from one formula to another with near-perfect accuracy. The formulas are essentially identical and interchangeable.
    Journal of pediatric urology 01/2014; 10(2). DOI:10.1016/j.jpurol.2013.12.007 · 0.90 Impact Factor
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    ABSTRACT: Approximately 20% of boys with posterior urethral valves develop ESRD; however, few factors associated with the risk of ESRD have been identified. The objective of this study was to determine if renal parenchymal area, defined as the area of the kidney minus the area of the pelvicaliceal system on first postnatal ultrasound, is associated with the risk of ESRD in infants with posterior urethral valves. A retrospective cohort of boys who were diagnosed with posterior urethral valves at less than 6 months of age between 1988 and 2011 and followed for at least 1 year at a free-standing children's hospital was assembled. Cox proportional hazard regression and Kaplan-Meier analysis were used to estimate the association between renal parenchymal area and time to ESRD. Cox models were adjusted for age at presentation, minimum creatinine 1 month after bladder decompression, and vesicoureteral reflux. Sixty patients were followed for 393 person-years. Eight patients developed ESRD. Median renal parenchymal area was 15.9 cm(2) (interquartile range=13.0-21.6 cm(2)). Each 1-cm(2) increase in renal parenchymal area was associated with a lower risk of ESRD (hazard ratio, 0.64; 95% confidence interval, 0.42 to 0.98). The rate of time to ESRD was 10 times higher in boys with renal parenchymal area<12.4 cm(2) than boys with renal parenchymal area≥12.4 cm(2) (P<0.001). Renal parenchymal area could best discriminate children at risk for ESRD when the minimum creatinine in the first 1 month after bladder decompression was between 0.8 and 1.1 mg/dl. In boys with posterior urethral valves presenting during the first 6 months of life, lower renal parenchymal area is associated with an increased risk of ESRD during childhood. The predictive ability of renal parenchymal area, which is available at time of diagnosis, should be validated in a larger, prospectively-enrolled cohort.
    Clinical Journal of the American Society of Nephrology 12/2013; 9(3). DOI:10.2215/CJN.08700813 · 4.61 Impact Factor
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    ABSTRACT: We hypothesized that active surveillance of the adolescent varicocele was not associated with a high prevalence of suboptimal semen analysis (SA) and that those with abnormal SA had smaller testicular volumes and larger volume differentials. An IRB-approved retrospective cohort study of adolescents with a clinically detected varicocele was conducted. Patients were initially observed with serial scrotal ultrasounds (ScrUS) evaluating testicular size and differential. SA was routinely collected in Tanner V individuals, around age 18 years. Prevalence of normal SA parameters was calculated and logistic regression was used to model the ability of age at presentation and testicular volume parameters to predict a normal SA. A cohort of 73 patients underwent surveillance with a mean (SD) age at presentation of 15.5 (2.3) years. Median follow-up was 2.7 years during which time subjects received a median of 3 ScrUS. A low total motile count (TMC) was found in 66% (48/73). Neither age at presentation nor testicular volume differential could predict normal semen volume, density, sperm motility, or TMC. Total testicular volume from the final ultrasound predicted TMC (p=0.008), however, the collective observations of volume during the entire period of surveillance could not predict TMC (p=0.847). There is a high prevalence of suboptimal SA in adolescents with a varicocele who are followed with active surveillance. Total testicular volume can predict TMC at the end of adolescence, but not throughout.
    The Journal of urology 11/2013; 191(5). DOI:10.1016/j.juro.2013.11.020 · 4.47 Impact Factor
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    ABSTRACT: To study the relationship between myosin light chain phosphorylation of the detrusor muscle and spontaneous smooth muscle contractions in a rabbit model of partial outlet obstruction. New Zealand white rabbit urinary bladders were partially obstructed for 2 weeks. Rabbits were euthanized, detrusor muscle strips were hung on a force transducer and spontaneous activity was measured at varying concentrations (0-0.03 μM/L) of the Rho-kinase inhibitors GSK 576371 or 0.01 μM/L Y27632. Basal myosin light chain phosphorylation was measured by 2-D gel electrophoresis in control and GSK 576371-treated strips. Both drugs suppressed the force of spontaneous contractions, whereas GSK 576371 had a more profound effect on the frequency of the contractions. The IC50 values for the inhibition of frequency and force of spontaneous contractions were 0.17 μM/L and 0.023 μM/L for GSK 576371, respectively. The compound significantly decreased the basal myosin light chain phosphorylation from 28.0 ± 3.9% to 13.5 ± 1.9% (P < 0.05). At 0.01 μM/L, GSK 576371 inhibited spontaneous bladder overactivity by 50%, but inhibited carbachol-elicited contractions force by just 25%. These data suggest that Rho-kinase regulation of myosin light chain phosphorylation contributes to the spontaneous detrusor activity induced by obstruction. This finding could have therapeutic implications by providing another therapeutic option for myogenic, overactive bladder.
    International Journal of Urology 08/2013; 21(3). DOI:10.1111/iju.12247 · 2.41 Impact Factor
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    ABSTRACT: Caldesmon (CaD), a component of smooth muscle thin filaments, binds actin, tropomyosin, calmodulin, and myosin and inhibits actin-activated ATP hydrolysis by smooth muscle myosin. Internal deletions of the chicken CaD functional domain that spans from amino acids (aa) 718 to 731, which corresponds to aa 512-530 including the adjacent aa sequence in mouse CaD, lead to diminished CaD-induced inhibition of actin-activated ATP hydrolysis by myosin. Transgenic mice with mutations of five aa residues (Lys(523) to Gln, Val(524) to Leu, Ser(526) to Thr, Pro(527) to Cys, and Lys(529) to Ser), which encompass the ATPase inhibitory determinants located in exon 12, were generated by homologous recombination. Homozygous (-/-) animals did not develop, but heterozygous (+/-) mice carrying the expected mutations in the CaD ATPase inhibitory domain (CaD mutant) matured and reproduced normally. The peak force produced in response to KCl and electrical field stimulation (EFS) by the detrusor smooth muscle (DSM) from the CaD mutant was high compared to that of the wild type (WT). CaD mutant mice revealed non-voiding contractions during bladder filling on awake cystometry, suggesting that the CaD ATPase inhibitory domain suppresses force generation during the filling phase, and this suppression is partially released by mutations in 50% of CaD in heterozygous. Our data show for the first time a functional phenotype, at the intact smooth muscle tissue and in vivo organ levels, following mutation of a functional domain at the C-terminal region of CaD.
    AJP Renal Physiology 08/2013; 305(10). DOI:10.1152/ajprenal.00174.2013 · 3.25 Impact Factor
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    ABSTRACT: Barrington's nucleus, in the pons, regulates micturition through spinal projections to preganglionic parasympathetic neurons. The stress neuropeptide, corticotropin-releasing factor (CRF) is prominent in these projections and has an inhibitory influence. Social stress in rats causes urinary retention and abnormal urodynamics resembling those produced by partial bladder outlet obstruction (pBOO) and this is associated with CRF upregulation in Barrington's nucleus. Here we examined the role of CRF in social stress- and pBOO-induced urodynamic dysfunction by assessing the ability of a CRF1 receptor antagonist to alter these effects. Male rats exposed to repeated resident-intruder stress were administered vehicle or a CRF1 antagonist (NBI-30775) daily prior to the stress. Urodynamic function was recorded in the unanesthetized state 72 h after the final stress. NBI-30775 prevented the increased intermicturition interval, micturition volume and bladder capacity produced by social stress, but not the increase in CRF expression in Barrington's nucleus neurons. The urinary dysfunction was also partly prevented by shRNA targeting of CRF in Barrington's nucleus suggesting that stress-induced urinary dysfunction results in part from CRF upregulation in Barrington's nucleus and enhanced postsynaptic effects in the spinal cord. Finally, NBI-30775 improved urodynamic function of rats that had pBOO of 2 week duration when administered daily during the second week, but did not block the increase in CRF expression in Barrington's nucleus neurons. These findings implicate a role for Barrington's nucleus CRF in stress- and pBOO-induced urodynamic changes and suggest that CRF1 antagonists may be useful therapeutic agents for the treatment of urinary dysfunction.
    AJP Regulatory Integrative and Comparative Physiology 04/2013; 304(11). DOI:10.1152/ajpregu.00257.2012 · 3.11 Impact Factor

  • The Journal of Urology 04/2013; 189(4):e116-e117. DOI:10.1016/j.juro.2013.02.1670 · 4.47 Impact Factor

  • The Journal of Urology 04/2013; 189(4):e74. DOI:10.1016/j.juro.2013.02.1560 · 4.47 Impact Factor
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    ABSTRACT: Purpose: There are few normative data on semen analyses in youths at risk for but not presenting with infertility. Standard practice among infertility specialists includes evaluation of 2 separate semen samples, given the degree of within subject variability. We hypothesized that males transitioning from pediatric to adult care who are at risk for infertility would similarly have this variability. Materials and methods: We retrospectively reviewed patients with a history of cryptorchidism or varicocele who submitted 2 semen samples for evaluation of fertility potential. The within subject coefficient of variation and intraclass correlation coefficient were calculated for each semen parameter to evaluate reproducibility and reliability, respectively. Results: A total of 79 subjects were studied. Mean ± SD age was 18.8 ± 1.2 years (range 17.8 to 24.7). The within subject coefficient of variation was high for each semen parameter, ranging from 36% for volume and motility to 82% for total motile count. Intraclass correlation coefficient for a single semen analysis ranged from 0.55 for motility to 0.88 for total count. Intraclass correlation coefficient for total motile count was 0.78 (95% CI 0.67-0.85), consistent with substantial reliability. Conclusions: Although we observed within patient variability of individual semen analysis parameters, overall there was substantial agreement between consecutive semen analyses in this population at risk for infertility, particularly regarding total motile count, which is the most important determinant of fertility from a semen analysis. Therefore, it is possible to appropriately classify some young men based on the result of a single measurement as they transition from pediatric to adult care.
    The Journal of urology 02/2013; 190(2). DOI:10.1016/j.juro.2013.02.030 · 4.47 Impact Factor
  • Matthew S Christman · Stephen A Zderic · Thomas F Kolon ·
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    ABSTRACT: Purpose: We determined relative semen quality in youths diagnosed with cryptorchidism or varicocele as a surrogate for ultimate paternity potential. We hypothesized that youths with varicocele would be at lower risk for subfertility based on semen analysis than their counterparts with surgically corrected cryptorchidism. Materials and methods: We retrospectively reviewed the records of patients with a history of cryptorchidism or varicocele. Patients were placed in 1 of 3 groups based on diagnosis, including group 1-untreated varicocele, group 2-treated bilateral cryptorchidism and group 3-treated unilateral cryptorchidism. Age and semen parameters (density, volume, count, motility and total motile count) were compared for each group. Results: A total of 193 subjects were studied. Median age was 18.3 (IQR 18.1-19.3), 18.6 (IQR 18.3-21.0) and 18.5 years (IQR 18.2-19.6) in the 76 group 1, 21 group 2 and 96 group 3 patients, respectively. Total motile count in groups 1, 2 and 3 was 14.6 (IQR 4.7-29.3), 4.0 (IQR 0-38.0) and 34.1 million sperm (IQR 7.6-90.8), respectively. No significant difference existed between the groups in age, volume (p = 0.106) or motility (p = 0.197). However, density (p = 0.0001), count (p = 0.0001) and total motile count (p = 0.0002) achieved significance. For each of these parameters a significant difference was noted for group 1 vs 3 and group 2 vs 3 but not for group 1 vs 2. Conclusions: The semen quality of youths with varicocele more closely resembles that of youths with bilateral cryptorchidism than those with unilateral cryptorchidism. This is concerning and should challenge current treatment paradigms for adolescents with varicocele.
    The Journal of urology 02/2013; 190(4 Suppl). DOI:10.1016/j.juro.2013.02.017 · 4.47 Impact Factor
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    ABSTRACT: Protein kinase C (PKC)-potentiated inhibitory protein of 17 kDa (CPI-17) inhibits myosin light chain phosphatase, altering levels of myosin light chain phosphorylation and Ca(2+)-sensitivity in smooth muscle. In this study we characterized the CPI-17 promoter and identified binding sites for GATA-6 and nuclear factor-kappa B (NF-κB). GATA-6 and NF-κB up-regulated CPI-17 expression in cultured human and mouse bladder smooth muscle (BSM) cells in an additive manner. CPI-17 expression was decreased upon GATA-6 silencing in cultured BSM cells and in BSM from NF-κB knockout (KO) mice. Moreover, force maintenance by BSM strips from KO mice was decreased compared with wild-type. GATA-6 and NF-κB overexpression was associated with CPI-17 overexpression in BSM from men with benign prostatic hyperplasia (BPH)-induced bladder hypertrophy and in a mouse model of bladder outlet obstruction. Thus, aberrant expression of NF-κB and GATA-6 deregulates CPI-17 expression and contractile function of smooth muscle. Our data provide insight into how GATA-6 and NF-κB mediate CPI-17 transcription, PKC-mediated signaling, and BSM remodeling associated with lower urinary tract symptoms in patients with BPH.
    Molecular and Cellular Biology 12/2012; 33(5). DOI:10.1128/MCB.00626-12 · 4.78 Impact Factor
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    ABSTRACT: Protein kinase C (PKC) and BK channels are down-regulated in the detrusor smooth muscle (DSM) in partial bladder outlet obstruction (PBOO). DSM from these bladders display increased spontaneous activity. This study examines the involvement of PKC in the regulation of spontaneous and evoked DSM contractions, and whether pharmacologic inhibition of PKC in normal DSM contributes to increased detrusor excitability. Results indicate the PKC inhibitor, bisindolylmaleimide 1 (Bim-1), prevented a decline in the amplitude of spontaneous DSM contractions over time in vitro, and these contractions persist in the presence of tetrodotoxin. Bim-1 also reduced the basal DSM tone, and the ability to maintain force in response to electrical field stimulation (EFS), but did not affect maximum contraction. PKC activator, Phorbol 12, 13-dibutyrate (PDBu), significantly reduced the amplitude, and increased the frequency of spontaneous contractions at low concentrations (10nM), while causing an increase in force at higher concentrations (1µM). Pre-incubation of DSM strips with iberiotoxin (IBTX) prevented the inhibition of spontaneous contractions by PDBu. BK channel openers, isopimaric acid (ISPA), and NS1619 reduced the Bim-1-induced enhancement of spontaneous contractions in DSM strips. Our data suggest that PKC has a biphasic activation profile in the DSM, and that it may play an important role in maintaining the quiescent state of the normal bladder during storage through the effects on BK channel, while helping to maintain force required for bladder emptying. The data also suggests that PKC dysfunction, as seen in PBOO, contributes to detrusor over activity.
    AJP Renal Physiology 12/2012; 304(5). DOI:10.1152/ajprenal.00639.2011 · 3.25 Impact Factor
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    ABSTRACT: We set out to characterize the voiding phenotypes of male mice to a water avoidance stress (WAS) protocol and compare the molecular changes with those induced by surgically induced partial bladder outlet obstruction (pBOO). Six-week-old male Swiss Webster mice housed with sibling littermates were individually placed on a platform centered in the middle of a water filled basin for 1 hr daily for 4 weeks. A non stressed cohort of sibling littermates served as controls. Measured end points included voiding frequency, voided volume, bladder mass, and in vivo cystometry. Molecular end points included myosin heavy chain (MHC) isoform distribution by PCR, and nuclear translocation of hypoxia inducible factor (HIF1α) and the nuclear factor of activated T-cells (NFAT) by gel shift assay. These molecular endpoints were compared with samples from male mice undergoing anatomic pBOO. WAS resulted in increased average voided volumes and bladder mass, and a decrease in voiding frequency (P < 0.05). The slower MHC A isoform was only expressed in the pBOO group that developed severe hypertrophy. Gel shift assays revealed substantial increases in HIF1-α nuclear translocation in the group subjected to pBOO that developed severe hypertrophy but minimal changes in the pBOO group that developed minimal hypertrophy and the swim stress groups. The WAS model induces moderate bladder wall hypertrophy in the absence of any surgical manipulation.
    Neurourology and Urodynamics 09/2012; 31(7):1185-9. DOI:10.1002/nau.22207 · 2.87 Impact Factor
  • Matthew Christman · Kate Kraft · Greg Tasian · Stephen Zderic · Thomas Kolon ·

    The Journal of Urology 04/2012; 187(4):e557-e558. DOI:10.1016/j.juro.2012.02.1757 · 4.47 Impact Factor
  • Matthew Christman · Thomas Kolon · Douglas Canning · Stephen Zderic ·

    The Journal of Urology 04/2012; 187(4):e554. DOI:10.1016/j.juro.2012.02.1750 · 4.47 Impact Factor

Publication Stats

2k Citations
555.93 Total Impact Points


  • 1990-2015
    • The Children's Hospital of Philadelphia
      • • Department of Urology
      • • Department of Anesthesia and Critical Care Medicine
      Filadelfia, Pennsylvania, United States
  • 2009-2013
    • William Penn University
      Filadelfia, Pennsylvania, United States
  • 2011
    • Beverly Hospital, Boston MA
      BVY, Massachusetts, United States
  • 1987-2006
    • University of Pennsylvania
      • • Department of Pathobiology
      • • Division of Urology
      • • Department of Medicine
      Filadelfia, Pennsylvania, United States
  • 1988-1994
    • Hospital of the University of Pennsylvania
      • Division of Urology
      Filadelfia, Pennsylvania, United States
    • Pennsylvania Medical Society
      Philadelphia, Pennsylvania, United States