Activation of PKC delta in the rat corpus luteum during pregnancy. Potential role of prolactin signaling

Maintenance of pregnancy in the rat requires the corpus luteum. At a time when rat placental lactogens (rPLs) are required to support progesterone production by the corpus luteum and when relaxin expression is initiated, expression of a specific protein kinase C (PKC) isoform, PKC delta, is dramatically increased. We therefore assessed whether prolactin (PRL) receptor activation promotes activation of PKC delta in a luteinized granulosa cell model. We also assessed the activation status of PKC delta in corpora lutea obtained when the corpus luteum is exposed to chronically high concentrations of rPLs. The activity of PKC delta was assessed by two means: an immune complex (IC) assay and Western blotting with a phospho-epitope-specific antibody that detects PKC delta phosphorylated on serine 662. PKC delta activation in the IC kinase assay was determined by the ability of immunoprecipitated PKC delta to phosphorylate the PKC delta-preferential substrate small heat shock protein (HSP-27). Treatment of luteinized rat granulosa cells with phorbol myristate acetate, a known activator of PKC, promoted a 7-fold increase in HSP-27 phosphorylation by PKC delta. Similarly, immunoreactivity with the phospho-epitope-specific PKC delta antibody was increased in extracts prepared from luteinized granulosa cells treated with phorbol myristate acetate or following in vitro activation of recombinant PKC delta. Using these assays, we assessed whether PRL receptor agonists were capable of activating PKC delta in luteinized granulosa cells. PRL receptor agonists induced translocation PKC delta from the cytosolic to the Triton-soluble membrane fraction and increased PKC delta activity assessed by both IC kinase assay and Western blotting with phospho-epitope-specific PKC delta antibody. Analysis of PKC delta activity in corpora lutea obtained during pregnancy by both the IC kinase assay and Western blotting with the phospho-epitope-specific PKC delta antibody revealed that PKC delta activity was increased throughout the second half of pregnancy. These results demonstrate that PRL receptor activation promotes the acute activation of PKC delta in luteinized rat granulosa cells. At a time when the rat is exposed to chronically high concentrations of rPLs, PKC delta is increasingly expressed and active.

Multisubstrate biodegradation kinetics of naphthalene, phenanthrene, and pyrene mixtures

Biodegradation kinetics of naphthalene, phenanthrene and pyrene were studied in sole-substrate systems, and in binary and ternary mixtures to examine substrate interactions. The experiments were conducted in aerobic batch aqueous systems inoculated with a mixed culture that had been isolated from soils contaminated with polycyclic aromatic hydrocarbons (PAHs). Monod kinetic parameters and yield coefficients for the individual compounds were estimated from substrate depletion and CO(2) evolution rate data in sole-substrate experiments. In all three binary mixture experiments, biodegradation kinetics were comparable to the sole-substrate kinetics. In the ternary mixture, biodegradation of naphthalene was inhibited and the biodegradation rates of phenanthrene and pyrene were enhanced. A multisubstrate form of the Monod kinetic model was found to adequately predict substrate interactions in the binary and ternary mixtures using only the parameters derived from sole-substrate experiments. Numerical simulations of biomass growth kinetics explain the observed range of behaviors in PAH mixtures. In general, the biodegradation rates of the more degradable and abundant compounds are reduced due to competitive inhibition, but enhanced biodegradation of the more recalcitrant PAHs occurs due to simultaneous biomass growth on multiple substrates. In PAH-contaminated environments, substrate interactions may be very large due to additive effects from the large number of compounds present.

Renal renin-angiotensin system dysregulation caused by partial bladder outlet obstruction in fetal sheep

BACKGROUND

To determine whether fetal renal obstruction activates the renal renin-angiotensin system (RAS), an important mediator in normal kidney development and obstructive nephropathy, we used a model of fetal partial bladder outlet obstruction (PBOO).

METHODS

Total RNA and protein was extracted from kidney of sheep fetuses with partial bladder outlet obstruction created at 95 days gestation, after 2 (N = 6) and 5 weeks of obstruction (term; N = 6), and from normal fetal sheep at various time points between 60 and 135 days of gestation (total N = 19). Relative levels of mRNA for renin, angiotensinogen, type 1 and 2 angiotensin II (Ang II) receptors (AT-1 and AT-2), and transforming growth factor-beta1 (TGF-beta1) were assessed by semiquantitative reverse transcription-polymerase chain reaction. Expression levels of AT-2 receptor protein were measured by Western blot analysis.

RESULTS

Renin mRNA expression was increased (250%) after two weeks of obstruction. In normal fetuses, AT-1 expression was low at 60 to 75 days of gestation and increased toward the end of gestation, whereas AT-2 expression showed a reversed pattern. At 109 days, PBOO caused an increased expression of AT-2 mRNA compared with normals (400%). Correspondingly, AT-2 receptor protein was more abundant in obstructed kidneys. TGF-beta1 mRNA expression was significantly increased in obstructed kidneys at 109 days gestation.

CONCLUSIONS

These observations confirm the reciprocal developmental regulation of AT-1 and AT-2 receptors' expression, suggesting their functional role in renal development. Partial bladder outlet obstruction produces specific alterations: increased renin expression and altered balance of receptor subtypes, which may induce altered functional and vascular regulation of the obstructed fetal kidney. TGF-beta1, a mediator of Ang II-induced fibrosis, may play a role in inducing and propagating interstitial fibrosis.

Pediatric retroperitoneoscopic nephrectomy using 2 mm. instrumentation

PURPOSE

We describe several modifications of the retroperitoneoscopic approach to nephrectomy for benign renal disease, including the use of 2 mm. instrumentation and prone patient positioning.

MATERIALS AND METHODS

A total of 14 children underwent retroperitoneoscopic nephrectomy in the prone position. An inflatable dissecting device was inserted into the retroperitoneum after a small muscle splitting incision was made at the lateral border of the sacrospinalis muscle approximately 1 cm. below the costovertebral angle. After inflation the dissecting device was replaced with a 5 mm. cannula and pneumoretroperitoneum was maintained with carbon dioxide insufflation. Two 2 mm. trocars were then placed under endoscopic guidance. Dissection was performed using 2 mm. instrumentation and the specimen was retrieved through the largest port site.

RESULTS

Nephrectomy was performed in 9 girls and 5 boys 3 months to 9.8 years old. The preoperative diagnosis included chronic pyelonephritis with minimal renal function, reflux with a nonfunctioning kidney, multicystic dysplastic kidney, an upper pole dysplastic moiety with an associated ureterocele and a dysplastic kidney with a vaginal ectopic ureter. Mean operative time for retroperitoneoscopic nephrectomy was 142 minutes with an estimated blood loss of less than 15 ml. Contralateral ureteral reimplantation was performed after retroperitoneoscopic dissection in 5 patients. Overall average hospital stay was 2 days and there were no complications.

CONCLUSIONS

Several modifications of the retroperitoneal approach, including the use of prone patient positioning and 2 mm. instrumentation for visualization and dissection, may improve the safety and efficacy of this technique in children.

Experimental fetal vesicoureteral reflux induces renal tubular and glomerular damage, and is associated with persistent bladder instability

PURPOSE

We assessed renal function and urodynamic status in animals with experimental congenital vesicoureteral reflux.

MATERIALS AND METHODS

Vesicoureteral reflux was surgically induced in male sheep fetuses at 95 days of gestation. After birth the animals were maintained on antibiotic prophylaxis. At ages 1 week and 6 months reflux was assessed by fluoroscopic voiding cystography. Cystometrography was performed with the animals awake. Serum creatinine, inulin clearance and the excretion of urinary N-acetyl-beta-D-glucosaminidase were measured at ages 1 week, 1 month and 6 months by surveillance urine cultures. Urinary concentrating capacity was assessed by desmopressin testing at ages 1 and 6 months.

RESULTS

Nine animals (18 renal units) were born after the induction of reflux. There was no reflux in 2 renal units, while reflux was mild in 2, moderate in 5 and severe in 9. In the 6 animals available for followup at age 6 months only severe reflux persisted. Reflux resolution was associated with normalization of bladder urodynamics. Surveillance urine cultures were negative until age 6 months, when infection developed in 3 of the 6 lambs. In all animals serum creatinine was normal during followup. Glomerular filtration rate in the lambs with reflux was no different from normal at age 1 week but it was significantly less than normal independent of infection at age 6 months (2.7 versus 3.9 ml./kg. per minute, p = 0.002). As an indicator of renal tubular injury the ratio of N-acetyl-beta-D-glucosaminidase-to-creatinine remained significantly higher in animals with reflux than in normal animals from ages 1 week to 6 months (51.0 versus 10.2 IU/mg., p = 0.03). Maximal concentrating ability after desmopressin testing was already less than normal by age 1 month with a maximal increase of 98 versus 435 mOsm./l. in lambs with reflux versus normal lambs (p <0.0001). It was further impaired by age 6 months. Urodynamic evaluation of the animals with reflux revealed decreased bladder compliance at age 1 week with normal voiding pressure. In addition, in those with reflux there was a more pronounced immature voiding pattern with multiple phasic contractions due to sphincteric activity as well as a post-void bladder contraction.

CONCLUSIONS

Our model of fetal vesicoureteral reflux induces alterations in renal function that are consistent with clinical observations and marked by altered tubular function but a relatively mild decrease in glomerular filtration. Bladder dynamics are altered, consistent with observations in human neonates with high grade reflux and bladder instability. Whether this represents cause or effect remains unclear. Our model permits focused study of the interaction of these factors in neonatal reflux and may allow the application of more specific therapies, particularly those directed toward mechanisms of renal and bladder dysfunction.

Fetal partial urethral obstruction causes renal fibrosis and is associated with proteolytic imbalance

PURPOSE

We determine whether fetal bladder outlet obstruction induces renal fibrosis, and is associated with an alteration in the regulation of connective tissue degradation and the presence of fibrogenic interstitial cells.

MATERIALS AND METHODS

Partial bladder outlet obstruction was surgically induced in 33 fetal sheep at 95 days of gestation. These animals and 24 normal age matched controls were sacrificed at 109, 116 and 135 (term) days of gestation, and the kidneys were rapidly retrieved, drained and weighed. Representative whole kidney samples were snap frozen for assessment of deoxyribonucleic acid, protein and collagen content. Morphometric analysis and alpha-smooth muscle actin immunohistochemistry were performed on histological specimens from formalin fixed kidneys. Tissue extract from fresh kidney specimens were analyzed for metalloproteinase and tissue inhibitor of metalloproteinase activity. Urine samples obtained at the time of sacrifice were analyzed for electrolyte, creatinine and N-acetyl glucosaminidase excretion.

RESULTS

All obstructed kidneys were hydronephrotic and larger than age matched controls. Obstructed kidneys at term showed interstitial fibrosis, as measured by increased extracellular matrix volume fraction (45% in male obstructed kidneys versus 2.5% in normal male kidneys, p = 0.0004), increased total collagen content (120 mg./kidney in male obstructed versus 20 mg. in normal male animals, p = 0.016) and collagen/deoxyribonucleic acid content per kidney (2.78 versus 0.53 mg./mg., p = 0.016). Metalloproteinase-1 activity was significantly lower in obstructed kidneys (210 versus 380 U./mg. protein in normal kidneys). Tissue inhibitor of metalloproteinase activity was undetectable in both groups. The presence of an increased population of myofibroblasts often associated with fibrotic processes was seen by alpha-smooth muscle actin staining which was localized to interstitial cells throughout the cortex in obstructed kidneys.

CONCLUSIONS

Fetal partial bladder outlet obstruction induces renal interstitial fibrosis as early as 2 weeks after obstruction. A possible mechanism for this process is a shift in proteolytic activity to reduce matrix degradation in obstructed kidneys. These changes might be mediated by the increased number of fibrogenic interstitial cells. The observations suggest several potential approaches to developing an understanding of congenital obstructive uropathy.

The incidence of intersexuality in children with cryptorchidism and hypospadias: stratification based on gonadal palpability and meatal position

PURPOSE

The combined findings of cryptorchidism and hypospadias often indicate the existence of an intersex state. Testicular maldescent and incomplete tubularization of the urethral plate occur in a spectrum with the severity of the 2 processes likely dependent on the degree of pathophysiology in the androgenic hormonal axis. The incidence of intersexuality in children with undescended testes, hypospadias and otherwise nonambiguous male genitalia has been reported to be 27%. Although the likelihood of genotypic or gonadal ambiguity has previously been associated with meatal position in this population, to our knowledge our study is the first to evaluate the incidence of intersexuality relative to whether the undescended testis is palpable or nonpalpable.

MATERIALS AND METHODS

The database at our hospital was searched for all cases of undescended testes (2,105) and hypospadias (1,057) between 1982 and 1996. Radiographic, histological and karyotypic data were compiled for all patients presenting with both diagnoses. Gonadal palpability (palpable versus nonpalpable) and meatal position (anterior versus mid versus posterior) were recorded and correlated with the likelihood of identifying an intersex condition. Ten boys with a diagnosis of undescended testes subsequent to inguinal hernial repair were excluded from study. Patients with congenital adrenal hyperplasia or complete testicular feminization were also excluded from study due to the clearly female appearance of the external genitalia. Statistical significance was assessed using Fisher's exact test.

RESULTS

We identified 79 patients presenting with undescended testes, hypospadias and a phallus that was believed to be a possible penis. Intersex conditions were identified with nearly equal frequency in the 44 cases of unilateral (30%) and 35 of bilateral (32%) cryptorchidism. In the unilateral undescended testes group patients with a nonpalpable testis were at least 3-fold more likely to have an intersex condition than those with a palpable undescended testis (50 versus 15%, p = 0.02). In the bilateral group patients with 1 or more nonpalpable testes were also nearly 3-fold as likely to have an intersex condition than those with bilateral palpable undescended gonads (47 versus 16%, p = 0.07). Meatal position was graded as anterior in 33% of cases, mid in 25% and posterior in 41% with the more posterior location conferring a significantly greater likelihood of an intersex condition (anterior 2 of 26, mid 1 of 20 and posterior 21 of 33).

CONCLUSIONS

Gonadal palpability is an important predictor of an intersex state in unilateral and bilateral cases of cryptorchidism with hypospadias. Patients with an undescended testis that cannot be palpated are significantly more likely to have an intersex condition than those in whom the undescended testis may be palpated on physical examination. The severity of hypospadias likewise has a strong positive correlation with an intersex state.

Oxybutynin chloride inhibits proliferation and suppresses gene expression in bladder smooth muscle cells

PURPOSE

We test the hypothesis that oxybutynin chloride inhibits bladder smooth muscle cell proliferation.

MATERIALS AND METHODS

Cultured rat bladder smooth muscle cells were grown in Medium 199 supplemented with 10% fetal bovine serum in the presence of 0, 1, 10 and 100 microM. oxybutynin. Cell proliferation was assessed by counting cell numbers 48 and 96 hours after plating. To investigate the role of oxybutynin in bladder smooth muscle cell proliferation after mechanical stretch, cells were grown on silicone elastomer bottomed culture plates and subjected to cyclical stretch-relaxation for 48 hours in the presence of 10 microM. oxybutynin. Deoxyribonucleic acid synthesis was assessed by tritiated thymidine incorporation assay. To examine the effect of oxybutynin on stretch activated gene expression, bladder smooth muscle cells were subjected to stretch-relaxation for 2 hours with and without 10 microM. oxybutynin, and relative c-jun messenger (m) ribonucleic acid (RNA) levels were assessed by semiquantitative reverse transcriptase-polymerase chain reaction with normalization to glyceraldehyde-3-phosphate dehydrogenase mRNA levels.

RESULTS

The serum stimulated increase in bladder smooth muscle cell growth was inhibited by oxybutynin in a dose dependent manner. In bladder smooth muscle cells there was a 4.7-fold increase in deoxyribonucleic acid synthesis after mechanical stretch, which decreased by 40% (p <0.01) when cells were stretched in the presence of oxybutynin. Stretch stimulated significant increase in c-jun mNRA levels, which was significantly decreased by oxybutynin.

CONCLUSIONS

Oxybutynin chloride inhibits bladder smooth muscle cell proliferation induced by serum and mechanical stretch. A potential mechanism by which oxybutynin inhibits proliferation may be the down regulation of growth promoting genes, such as c-jun. We speculate that oxybutynin may be useful for preventing permanent hypertrophic bladder changes in addition to decreasing intravesical pressure.

Experimental fetal vesicoureteral reflux induces renal tubular and glomerular damage, and is associated with persistent bladder instability

PURPOSE

We assessed renal function and urodynamic status in animals with experimental congenital vesicoureteral reflux.

MATERIALS AND METHODS

Vesicoureteral reflux was surgically induced in male sheep fetuses at 95 days of gestation. After birth the animals were maintained on antibiotic prophylaxis. At ages 1 week and 6 months reflux was assessed by fluoroscopic voiding cystography. Cystometrography was performed with the animals awake. Serum creatinine, inulin clearance and the excretion of urinary N-acetyl-beta-D-glucosaminidase were measured at ages 1 week, 1 month and 6 months by surveillance urine cultures. Urinary concentrating capacity was assessed by desmopressin testing at ages 1 and 6 months.

RESULTS

Nine animals (18 renal units) were born after the induction of reflux. There was no reflux in 2 renal units, while reflux was mild in 2, moderate in 5 and severe in 9. In the 6 animals available for followup at age 6 months only severe reflux persisted. Reflux resolution was associated with normalization of bladder urodynamics. Surveillance urine cultures were negative until age 6 months, when infection developed in 3 of the 6 lambs. In all animals serum creatinine was normal during followup. Glomerular filtration rate in the lambs with reflux was no different from normal at age 1 week but it was significantly less than normal independent of infection at age 6 months (2.7 versus 3.9 ml./kg. per minute, p = 0.002). As an indicator of renal tubular injury the ratio of N-acetyl-beta-D-glucosaminidase-to-creatinine remained significantly higher in animals with reflux than in normal animals from ages 1 week to 6 months (51.0 versus 10.2 IU/mg., p = 0.03). Maximal concentrating ability after desmopressin testing was already less than normal by age 1 month with a maximal increase of 98 versus 435 mOsm./l. in lambs with reflux versus normal lambs (p <0.0001). It was further impaired by age 6 months. Urodynamic evaluation of the animals with reflux revealed decreased bladder compliance at age 1 week with normal voiding pressure. In addition, in those with reflux there was a more pronounced immature voiding pattern with multiple phasic contractions due to sphincteric activity as well as a post-void bladder contraction.

CONCLUSIONS

Our model of fetal vesicoureteral reflux induces alterations in renal function that are consistent with clinical observations and marked by altered tubular function but a relatively mild decrease in glomerular filtration. Bladder dynamics are altered, consistent with observations in human neonates with high grade reflux and bladder instability. Whether this represents cause or effect remains unclear. Our model permits focused study of the interaction of these factors in neonatal reflux and may allow the application of more specific therapies, particularly those directed toward mechanisms of renal and bladder dysfunction.

Oxybutynin chloride inhibits proliferation and suppresses gene expression in bladder smooth muscle cells

PURPOSE

We test the hypothesis that oxybutynin chloride inhibits bladder smooth muscle cell proliferation.

MATERIALS AND METHODS

Cultured rat bladder smooth muscle cells were grown in Medium 199 supplemented with 10% fetal bovine serum in the presence of 0, 1, 10 and 100 microM. oxybutynin. Cell proliferation was assessed by counting cell numbers 48 and 96 hours after plating. To investigate the role of oxybutynin in bladder smooth muscle cell proliferation after mechanical stretch, cells were grown on silicone elastomer bottomed culture plates and subjected to cyclical stretch-relaxation for 48 hours in the presence of 10 microM. oxybutynin. Deoxyribonucleic acid synthesis was assessed by tritiated thymidine incorporation assay. To examine the effect of oxybutynin on stretch activated gene expression, bladder smooth muscle cells were subjected to stretch-relaxation for 2 hours with and without 10 microM. oxybutynin, and relative c-jun messenger (m) ribonucleic acid (RNA) levels were assessed by semiquantitative reverse transcriptase-polymerase chain reaction with normalization to glyceraldehyde-3-phosphate dehydrogenase mRNA levels.

RESULTS

The serum stimulated increase in bladder smooth muscle cell growth was inhibited by oxybutynin in a dose dependent manner. In bladder smooth muscle cells there was a 4.7-fold increase in deoxyribonucleic acid synthesis after mechanical stretch, which decreased by 40% (p <0.01) when cells were stretched in the presence of oxybutynin. Stretch stimulated significant increase in c-jun mNRA levels, which was significantly decreased by oxybutynin.

CONCLUSIONS

Oxybutynin chloride inhibits bladder smooth muscle cell proliferation induced by serum and mechanical stretch. A potential mechanism by which oxybutynin inhibits proliferation may be the down regulation of growth promoting genes, such as c-jun. We speculate that oxybutynin may be useful for preventing permanent hypertrophic bladder changes in addition to decreasing intravesical pressure.

Normal urodynamics in patients with bladder exstrophy: are they achievable?

PURPOSE

Urodynamic study was performed in patients with exstrophy to determine the effect of bladder neck reconstruction and the ability to achieve normal urodynamics following surgery.

MATERIALS AND METHODS

A total of 30 exstrophy cases at different stages of reconstruction were retrospectively reviewed in terms of bladder capacity, compliance, stability and presence of detrusor contractions following urodynamic study.

RESULTS

Bladder capacity increased from a third predicted volume for age to half after reconstruction. Approximately 80% of patients had compliant and stable bladders before bladder neck reconstruction. Following bladder neck reconstruction approximately half of the patients maintained normal compliance with a smaller number maintaining normal stability. A quarter of patients maintained normal filling dynamics following bladder neck reconstruction, and 19% maintained normal filling and voiding dynamics after reconstruction.

CONCLUSIONS

The majority of closed exstrophy bladders have normal filling dynamics before bladder neck reconstruction. Compliance and stability are impaired following bladder neck reconstruction. Approximately 25% of patients with exstrophy may maintain normal detrusor function following reconstruction. However, less invasive alternatives to the Young-Dees-Leadbetter bladder neck reconstruction should be sought.

AP-1 mediates stretch-induced expression of HB-EGF in bladder smooth muscle cells

Mechanical induction of growth factor synthesis may mediate adaptive responses of smooth muscle cells (SMC) to increases in physical load. We previously demonstrated that cyclic mechanical stretch induces expression of the SMC, fibroblast, and epithelial cell mitogen heparin-binding epidermal growth factor-like growth factor (HB-EGF) in bladder SMC, an observation that suggests that this growth factor may be involved in compensatory bladder hypertrophy. In the present study we provide evidence that the activator protein-1 (AP-1) transcription factor plays a critical role in this mechanoinduction process. Rat bladder SMC were transiently transfected with a series of 5' deletion mutants of a promoter-reporter construct containing 1. 7 kb of the mouse HB-EGF promoter that was previously shown to be stretch responsive. The stretch-mediated increase in promoter activity was completely ablated with deletion of nucleotide positions -1301 to -881. Binding of AP-1, as evaluated by electrophoretic mobility shift assay, to a synthetic oligonucleotide containing an AP-1 binding site increased in response to stretch, and binding was inhibited by excess unlabeled DNA corresponding to nucleotides -993 to -973 from the HB-EGF promoter, a region that contains a previously recognized composite AP-1/Ets site. Stretch-induced promoter activity was significantly inhibited by site-directed mutagenesis of the AP-1 or Ets components of this site. Consistent with the promoter and gel-shift studies, curcumin, an inhibitor of AP-1 activation, suppressed the HB-EGF mRNA induction after stretch. Stretch also specifically increased mRNA levels for matrix metalloproteinase (MMP)-1, the promoter of which contains a functional AP-1 element, but not for MMP-2, the promoter of which does not contain an AP-1 element. The stretch response of the MMP-1 gene was also completely inhibited by curcumin. Collectively, these findings indicate that AP-1-mediated transcription plays an important role in the regulation of gene expression in bladder muscle in response to mechanical forces.

Box stitch modification of Hasson technique for pediatric laparoscopy

Laparoscopy has been recognized as the modality of choice for the treatment of many diseases in urology, gynecology, and general surgery. Although laparoscopy is minimally invasive, the most frequent complications are associated with entry through the abdominal wall. The Hasson (open) technique was developed to minimize the complications by entering the abdomen under direct vision. We have modified the Hasson technique with a stitch that is easy to perform, creates a tight fascial seal, allows easy exchange of trocars, and produces an effect that is cosmetically appealing.

Regulation of protein kinase C delta by estrogen in the MCF-7 human breast cancer cell line

We have previously shown that estrogen up-regulates expression of protein kinase C (PKC) delta in the rat and rabbit corpus luteum as well as in luteinized rat granulosa primary cell cultures. To determine whether a similar regulation of the PKC delta isoform by estrogen occurred in another estrogen responsive system, we investigated the estrogen receptor positive MCF-7 human breast cancer cells. In a characterization of PKC isoforms in MCF-7 cells we determined that PKC delta was the predominant PKC isoform. However in contrast to the effect of estrogen on PKC delta expression in ovarian cells, estrogen treatment of MCF-7 cells resulted in a significant decrease in PKC delta protein and mRNA expression in a time and dose dependent manner. Treatment of MCF-7 cells with 10(-10)-10(-8) M estrogen for 7 days down-regulated specifically PKC delta mRNA and protein while expression of other PKC isoforms was unchanged. The opposite regulation of PKC delta expression in ovarian and breast cancer cells prompted us to evaluate the type of estrogen receptor present in both cell types. Results showed that luteinized rat granulosa cells expressed predominantly estrogen receptor beta while the MCF-7 cells expressed predominantly estrogen receptor alpha and barely detectable levels of estrogen receptor beta. These results suggest that the differential ability of estrogen to regulate PKC beta expression could potentially be a result of differential signaling through the two estrogen receptor subtypes.

Follicle-stimulating hormone promotes histone H3 phosphorylation on serine-10

FSH promoted the rapid phosphorylation of the nuclear protein histone H3 in immature rat ovarian granulosa cells under experimental conditions that lead to cellular differentiation and not proliferation. FSH-stimulated histone H3 phosphorylation correlated with cAMP-dependent protein kinase A (PKA) activation and translocation of the PKA catalytic subunit to a nuclear-enriched fraction and was inhibited by the PKA inhibitor H89, and histone H3 phosphorylation was stimulated in cells treated with agents that raise intracellular cAMP levels such as forskolin and 8-bromo-cAMP. FSH-stimulated histone H3 phosphorylation in granulosa cells mapped to ser-10, a site previously identified as the PKA phosphorylation site in various mitotically active cells as the mitosis-specific phosphorylation site. Injection of the FSH analog PMSG to immature rats, which is known to stimulate granulosa cell proliferation as well as differentiation, also promoted histone H3 phosphorylation on ser-10 in granulosa cells. These results establish that FSH-stimulated histone H3 phosphorylation in granulosa cells is linked not only to granulosa cell mitosis but also to granulosa cell differentiation and that FSH-stimulated histone H3 phosphorylation on ser-10 in isolated granulosa cells is mediated by PKA. These results also identify the PKA-dependent histone H3 phosphorylation as an early nuclear protein marker for FSH-stimulated differentiation of granulosa cells. Based on the recently described function of histone H3 as a coactivator of transcription, these results are consistent with the hypothesis that phosphorylated histone H3 may facilitate PKA-dependent gene transcription in granulosa cells leading to the preovulatory phenotype.

Renal findings on radiological followup of patients with Beckwith-Wiedemann syndrome

PURPOSE

The Beckwith-Wiedemann syndrome is most commonly characterized by macroglossia and abdominal wall defect(s), and it carries a predisposition to embryonal tumors, including Wilms tumor. We report our experience with the character and incidence of renal disease in patients with the Beckwith-Wiedemann syndrome, and discuss the role of radiological followup.

MATERIALS AND METHODS

We reviewed the medical records of all patients diagnosed with the Beckwith-Wiedemann syndrome who were treated at our institution between March 1979 and February 1998. Radiological followup consisted of renal ultrasound at approximately 3 to 6-month intervals with the addition of computerized tomography or magnetic resonance imaging (MRI) in patients with an indeterminate lesion(s) or nephrogenic rest(s).

RESULTS

A total of 29 patients were identified. Of these cases renal ultrasound showed normal kidneys bilaterally in 19 (70%), simple cysts in 5 (19%), indeterminate lesion(s) in 2 (7%) and nephrocalcinosis in 1 (4%). Nephrogenic rests were followed with MRI in 1 patient, and 1 in whom a 2 cm. mass was revealed by followup MRI underwent partial nephrectomy and chemotherapy for stage I Wilms tumor.

CONCLUSIONS

The 3.7% incidence of Wilms tumor in our patients with the Beckwith-Wiedemann syndrome is similar to that in previously published reports. Aggressive follow-up by a sensitive radiological technique is warranted in cases of the Beckwith-Wiedemann syndrome, and associated hemihypertrophy and/or nephromegaly with or without evidence of a Wilms tumor precursor. The detection of suspected malignant disease at an early stage may permit curative nephron sparing surgery.

Obstruction stimulates COX-2 expression in bladder smooth muscle cells via increased mechanical stretch

Studies were performed to investigate the regulatory mechanism of bladder cyclooxygenase-2 (COX-2) expression after outlet obstruction. In situ hybridization of murine bladder tissues using COX-2-specific riboprobes demonstrated that COX-2 expression was induced predominantly in the bladder smooth muscle cells after outlet obstruction. To study the effect of increased mechanical stretch on COX isoform expression, cultured rat bladder smooth muscle cells were grown on silicone elastomer-bottomed plates coated with collagen type I and were subjected to continuous cycles of stretch/relaxation for variable duration. COX-1 mRNA levels did not change with stretch. COX-2 expression increased in a time-dependent manner after stretch, with maximal mRNA and protein levels occurring after 4 h. PGE2 levels increased more than 40-fold in the culture media after stretch, consistent with increased COX activity, and this was reduced to near completion in the presence of a COX-2 inhibitor, NS-398. Exposure to stretch over a 48-h period induced a 4.7 +/- 0.6-fold increase in tritiated thymidine incorporation rate. This increase in DNA synthesis was markedly suppressed when the cells were stretched in the presence of NS-398. We conclude that in bladder obstruction COX-2 activation occurs predominantly in the smooth muscle cells in response to mechanical stretch. Our findings also suggest that stretch-activated COX-2 expression may participate in bladder smooth muscle cell proliferation and thereby play a role in pathological bladder wall thickening after obstruction.

Reservoir calculi: a comparison of reservoirs constructed from stomach and other enteric segments

PURPOSE

The intestinal augmented bladder has an increased propensity to form urinary calculi. Predisposing risk factors include chronic bacteriuria, urinary stasis and mucus production. Gastric reservoirs have negligible mucus production and the ability to acidify the urine. We determined whether they also have a decreased incidence of stones.

MATERIALS AND METHODS

We retrospectively reviewed the records of all patients undergoing augmentation cyptoplasty (215) or creation of a freestanding reservoir (44) between May 1976 and March 1996. Of these cases 83 were augmented with stomach and 179 were constructed from other intestinal segments, (that is ileal, ileocecal, sigmoid and/or a combination of these). Presenting diagnosis, patient age, gender, additional surgical procedures, interval to stone formation and calculous composition were recorded. Patients were excluded from study when there was less than 1 year of followup, as were those with renal or pre-augmentation bladder calculi.

RESULTS

Stones formed in 32 of 207 patients (15%) after an average interval of 3.6 years (range 0.5 to 8.6). The majority of stones were composed of struvite (magnesium ammonium phosphate). Reservoirs containing gastric segments were significantly less likely to form calculi than those augmented with other intestinal segments (2 of 70 versus 30 of 137, p <0.0001 Fisher's exact test). Seven additional patients with pre-augmentation bladder stones who subsequently underwent gastrocystoplasty remain stone-free at an average followup of 3.0 years.

CONCLUSIONS

Calculous formation is rare in reservoirs that incorporate a gastric segment. In patients with gastric augmentation stones appear only to develop when the patient is on histamine blockade or has a propensity to form stones that only favor an acidic environment, such as uric acid.

Stretch activates heparin-binding EGF-like growth factor expression in bladder smooth muscle cells

Cultured rat bladder smooth muscle cells (SMC) were grown on collagen-coated silicone membranes and subjected to continuous cycles of stretch-relaxation. Semiquantitative RT-PCR analysis revealed a time-dependent increase in heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) mRNA levels after stretch, with maximal levels appearing after 4 h. Immunostaining for proHB-EGF revealed higher levels of HB-EGF protein in the stretched than in the nonstretched SMC. The ANG II receptor type 1 antagonist losartan markedly suppressed stretch-activated HB-EGF expression. ANG II levels were 3.3-fold higher in the stretch- than in the non-stretch-conditioned media. Stretch stimulation of bladder SMC that had been transiently transfected with an HB-EGF promoter-luciferase expression construct resulted in an 11-fold increase in reporter activity. Mechanical stretch induced a 4.7-fold increase in tritiated thymidine incorporation rate, and this was reduced by 25% in the presence of losartan. We conclude that mechanical stretch activates HB-EGF gene expression in bladder SMC and that this is mediated in part by autocrine ANG II secretion.

Percutaneous nephrolithotomy in infants and preschool age children: experience with a new technique

OBJECTIVES

To develop a less invasive method for performing percutaneous nephrolithotomy (PCNL) with the intent of decreasing the morbidity of the procedure in young children.

METHODS

A novel percutaneous renal access technique ("mini-perc") was developed using an 11F peel-away vascular access sheath. Tract dilation and insertion of the sheath into the collecting system was performed with a single pass over an access wire. PCNL was performed using pediatric instruments and electrohydraulic lithotripsy. Sheath design improvements were implemented that make it specific for pediatric PCNL.

RESULTS

Eleven procedures have been performed with the 11F sheath. Patient age ranged from 2 to 6 years (mean 3.4) and weight from 5 to 24 kg (mean 12.5). The average stone burden was 1.2 cm2. Mean procedure time, estimated blood loss, and length of hospitalization were 203 minutes, 25 mL, and 6 days, respectively. Six (85%) of 7 patients are currently stone free with an average follow-up of 12 weeks. No patient required transfusion, developed urosepsis, or had a procedure-related complication. One procedure was performed in an outpatient setting with no postoperative nephrostomy tube.

CONCLUSIONS

The 11F "mini-perc" technique was successful in rendering 85% of patients stone free with minimal morbidity. Its advantages over obtaining access with standard 24 to 34F access sheaths include a smaller skin incision, single-step dilation and sheath placement, good working access for pediatric instruments, variable length, and lower cost. In addition, the hypothesized decrease in renal and body wall trauma may result in less pain, reduced severity or risk of complications, and shorter hospital stays including the possibility of performing "tubeless" outpatient PCNLs. Further study is needed to confirm these possibilities.

Premature urachal closure induces hydroureteronephrosis in male fetuses

PURPOSE

Congenital hydronephrosis is more common in male individuals. We investigate whether an alteration in fetal bladder function induced by premature urachal closure contributes to fetal hydronephrosis, consequently explaining this male predominance.

MATERIALS AND METHODS

The urachus was clipped in 8 male and 4 female ovine fetuses at 95 days of gestation (term 140 days). Subjects were sacrificed, and the urinary tract was assessed at 109 and 116 days of gestation in 3 and 1 male fetuses, respectively, and at term in 4 male and 4 female lambs.

RESULTS

At 109 and 116 days of gestation 3 of the 4 male fetuses had upper tract dilatation. At term no female but 4 male lambs had hydroureteronephrosis, including some with marked pelvic dilatation and parenchymal thinning. At term mean bladder weight in the male animals with urachal clipping was 5.28 gm. (range 3.5 to 8.2), which was significantly greater than normal (p = 0.02). Bladder weight at term in the female lambs with urachal clipping was not different from normal values. Histological evaluation of the kidneys in the male lambs revealed cortical thinning and loss of medullary tissue, while the overall renal architecture was well preserved.

CONCLUSIONS

Our observations indicate that normal ovine fetal urinary tract function and drainage depend on urachal function and the timing of urachal closure. Therefore, fetal hydronephrosis is associated with this alteration in bladder function but it may also be associated with other factors, such as bladder sphincter maturation or prostate development. Our experiment shows that hydroureteronephrosis develops in ovine fetuses when all bladder drainage occurs via the urethra. This condition may be an amplification of the differences in bladder outlet resistance in human fetuses, which may explain the male predominance in the various forms of hydroureteronephrosis.

Experimental vesicoureteral reflux in the fetus depends on bladder function and causes renal fibrosis

PURPOSE

Prenatal diagnosis allows the early detection of vesicoureteral reflux in an increasing number of newborns, some of whom are born with impaired kidney function. This situation challenges our current understanding of the pathophysiology, natural history and, therefore, treatment of reflux. We created a fetal sheep model of vesicoureteral reflux to study the mechanisms of fetal reflux nephropathy.

MATERIALS AND METHODS

Vesicoureteral reflux was induced in fetal sheep at 95 days of gestation (term 140 days) by open bladder incision of the intravesical ureteral tunnel. All animals underwent urachal ligation and in female subjects mild bladder outlet obstruction was created with a gold ring.

RESULTS

At term reflux was detected in 18 of 28 renal units by filling cystography. Refluxing kidneys were hydronephrotic and larger than normal. At term mean kidney weight was 21.1 gm. (range 12.2 to 35.0) in male subjects with reflux compared to 8.5 gm. (range 6.5 to 11.3) in normal male subjects (p <0.001) and 11.5 gm. (range 8.5 to 15.8) in male subjects with urachal ligation only (p = 0.035). In female subjects there was no change in renal weight. Renal histology revealed a thin, structurally normal cortex with small subcortical cysts and a hypoplastic medulla with mesenchymal tissue replacing normal ducts. Total mean renal collagen content was significantly increased to 51.7 mg. (range 35 to 81) in the refluxing kidneys of male animals, while it was 23.8 mg. (range 12.1 to 38.4) in normal male animals (p = 0.03). The fractional excretion of sodium was elevated in refluxing kidneys based on sodium-to-creatinine ratios in bladder urine.

CONCLUSIONS

In a novel model of fetal vesicoureteral reflux we showed that prenatal reflux nephropathy is characterized by altered renal growth regulation, structural maldevelopment without overt dysplasia, excess matrix deposition and impaired excretory function.

Current findings in diagnostic laparoscopic evaluation of the nonpalpable testis

PURPOSE

We delineate the current findings and contribution of diagnostic laparoscopic evaluation in the management of nonpalpable testis.

MATERIALS AND METHODS

We reviewed all cases in which laparoscopy was considered the management associated with a nonpalpable testis in a 4-year period. Since our previous series, we have performed a careful examination for the testis after induction of anesthesia but before committing to laparoscopy. We recorded testis position and quality, character of the vas deferens and spermatic vessels, type of management and contribution of laparoscopy. We also reviewed contemporary published series and collated the findings of studies performed elsewhere.

RESULTS

We identified 263 nonpalpable testes in 225 patients between September 1992 and 1996. In 40 patients 46 testes (18%) were found during physical examination under anesthesia. Of the remaining cases considered appropriate for laparoscopy 215 with complete records were further analyzed. Only 12.6% could be considered missed on examination due to a viable testis distal to the inguinal ring. Of the testes 45.7% would have been found during inguinal exploration alone. In 9.8% of the patients there were intra-abdominal vanishing testes, while 4.2% had indeterminate cord structures on inguinal exploration that would have prompted abdominal extension without a laparoscopic demonstration that the vas and vessels entered the canal. A conventional inguinal incision would have provided optimal exposure for operative management in 34% of the testes. For testes distal to the internal ring when the vas and vessels were distinctly atretic we never identified a viable testis, while a normal appearing vas and vessel were associated with a 45% chance of a salvageable testis. Laparoscopy was informative regarding testis position in all cases in which it was performed.

CONCLUSIONS

In 13.2% of the cases laparoscopic findings precluded unnecessary abdominal exploration. The typical surgical incision for inguinal exploration would have left the surgeon compromised in 66% of the cases compared to the approach optimized as a result of laparoscopic testicular localization. Of the patients 34% arguably did not benefit from laparoscopy versus inguinal exploration. A simple examination under anesthesia significantly decreases the number of uninformative laparoscopic evaluations, and it is well worth the cost of a few minutes of operative time.