Pkd1-targeted mutation reveals a role for the Wolffian duct in autosomal dominant polycystic kidney disease.

Several life-threatening diseases of the kidney have their origins in mutational events that occur during embryonic development. In this study, we investigate the role of the Wolffian duct (WD), the earliest embryonic epithelial progenitor of renal tubules, in the etiology of autosomal dominant polycystic kidney disease (ADPKD). ADPKD is associated with a germline mutation of one of the two Pkd1 alleles. For the disease to occur, a second event that disrupts the expression of the other inherited Pkd1 allele must occur. We postulated that this secondary event can occur in the pronephric WD. Using Cre-Lox recombination, mice with WD-specific deletion of one or both Pkd1 alleles were generated. Homozygous Pkd1-targeted deletion in WD-derived tissues resulted in mice with large cystic kidneys and serologic evidence of renal failure. In contrast, heterozygous deletion of Pkd1 in the WD led to kidneys that were phenotypically indistinguishable from control in the early postnatal period. High-throughput sequencing, however, revealed underlying gene and microRNA (miRNA) changes in these heterozygous mutant kidneys that suggest a strong predisposition toward developing ADPKD. Bioinformatic analysis of this data demonstrated an upregulation of several miRNAs that have been previously associated with PKD; pathway analysis further demonstrated that the differentially expressed genes in the heterozygous mutant kidneys were overrepresented in signaling pathways associated with maintenance and function of the renal tubular epithelium. These results suggest that the WD may be an early epithelial target for the genetic or molecular signals that can lead to cyst formation in ADPKD.

When the Pain Becomes Unbearable: Case-Control Study of Mental Pain Characteristics Among Medically Serious Suicide Attempters.

The unbearable mental pain experience is recognized as a key antecedent of suicidal behavior. We aimed to examine the precise nature of the mental pain among medically serious suicide attempters (MSSAs), a population closely resembling those who died by suicide. We evaluated various factors of mental pain from the Orbach and Mikulincer Mental Pain Scale, as well as medical lethality and suicide intent. MSSAs were higher than non-MSSAs and psychiatric controls for Irreversibility of pain. Moreover, Emptiness predicted medical lethality, while Cognitive Confusion negatively predicted suicide intent level, controlling for hopelessness and depression. high sense of Irreversibility of pain as well as high Emptiness and low Cognitive Confusion are important risk factors for more severe suicidal behavior. Implications for identification of at-risk groups for suicide as well as for suicide prevention and treatment of suicidal individuals are discussed.

Areal and volumetric bone mineral density changes after renal transplantation in children: a longitudinal study.

INTRODUCTION: The effect of renal transplantation on areal bone mineral density (aBMD) in children has previously been studied. However, most previous reports did not include estimation of volumetric bone mineral density (vBMD) or analyze longitudinal data in these patients. In addition, updated reference standards for aBMD in children have recently been made available. METHODS: This retrospective study describes the longitudinal effect of renal transplantation on aBMD and vBMD in a cohort of 40 pediatric kidney transplant recipients. Lumbar spine aBMD measurements were obtained using dual-energy X-ray absorptiometry prior to transplant and yearly thereafter. vBMD values and z-scores were estimated as described in the most recently published references. RESULTS: A significant decrease in average aBMD and vBMD z-scores was observed within 1 year posttransplant, which did not recover during follow-up. The negative effect of transplantation on vBMD was blunted and vBMD z-scores were higher compared to aBMD. Linear mixed-effects model analysis demonstrated that lumbar spine aBMD and vBMD z-scores were inversely related to yearly prednisone dose (g/m2) but this effect was diminished as glomerular filtration rate was increased. CONCLUSIONS: Bone mineral density was negatively affected by renal transplantation in this cohort of pediatric patients. Estimation of vBMD appears to be appropriate for interpretation of the BMD changes occurring after renal transplant in children. The inverse relation between BMD z-scores and yearly prednisone dose suggests that ongoing posttransplant corticosteroid therapy may be responsible for the negative effect of transplantation on bone mineral density in this cohort.

Acute glomerulonephritis presenting with PRES: a report of 4 cases.

OBJECTIVE: Posterior reversible encephalopathy syndrome (PRES) occurs most commonly in the setting of known hypertension or use of immunosuppressive agents. DESIGN AND METHODS: We report four previously-well children who presented acutely with altered mentation, seizures and visual disturbances and were diagnosed with PRES. RESULTS: Only one child had a history of gross hematuria prior to the seizure. All four were discovered to be hypertensive only after onset of their neurological symptoms, and were subsequently diagnosed with glomerulonephritis. All four had rapid resolution of neurological symptoms with adequate treatment of hypertension. CONCLUSIONS: Blood pressure must be measured promptly in all children presenting with these symptoms. If elevated, the diagnosis of PRES should be strongly considered and a workup for renal disease pursued.

Prenatal diagnosis of intestinal pseudo-obstruction.

The appearance of polyhydramnios and dilated bowel loops on prenatal sonographic examination usually implies mechanical obstruction. The prognosis is variable, depending on the etiology. Congenital pseudo-obstruction, a potentially lethal disease, comprises a group of disorders characterized by intestinal obstruction in the absence of an anatomic lesion. This report focuses on the prenatal diagnosis of intestinal pseudo-obstruction, and two cases of transient congenital intestinal pseudo-obstruction in one family are described. In both, the prenatal sonographic presentation was of small bowel obstruction. In one case there was postnatal suspicion of neurogenic bladder, and in the other there was unilateral hydronephrosis. The sonographic appearance of intestinal pseudo-obstruction is similar to that of mechanical obstruction. The clues to the prenatal diagnosis of pseudo-obstruction include associated urinary tract abnormalities and a family history of pseudo-obstruction.

Growth inhibition of drug-resistant species of Plasmodium falciparum by domain structured N1,N2-derivatized hydrazines: denticity effects, redox switches, and reductant-driven redox-cycling.

Six analogs of bidentate 1-[pyridoxylidene]-2-phenyl]hydrazine, twelve analogs of N2O-tridentate 1-[pyridoxylidene]-2-[heteroaryl]hydrazine, and four O2N-tridentate analogs of 1-[pyridoxylidene]-2-[heteroaroyl] hydrazines were synthesized and characterized. Their solutions in water and DMSO were assayed in vitro for activity against a chloroquine-resistant species of P. falciparum obtained from Hadassah Hospital Blood Bank in Jerusalem. The O2N-tridentate group was essentially inactive, whereas the bidentate group, with N and O liganding atoms, exhibited slight activity against late-stage trophozoites and schizonts of P. falciparum. The N2O-tridentate group, by contrast, was remarkably active against resistant P. falciparum, highlighting the importance of the Denticity Effect in this system. It is assumed that the pyridoxal-based chelator acts as an iron redox mediator, controlling the first coordination sphere and, therefore, the immediate chemical environment of the iron. Chelation of iron-(II) presumably facilitates its oxidation..The Fe(II) --> Fe(III) intra-electron transfer, may be viewed as a switch ("redox switch"), controlling the thermodynamic stability and kinetic lability of the coordination shell. The redox-switch is accompanied by the appearance of a carbon-based Fe-(III)-chelate radical, capable of donating its free electron to the parasite-DNA, thus causing death. The antimalarial N2O-tridentate Fe(III)-chelates appear to be prone to redox-switch, and tend to be converted into their Fe(II) species, whereas the inactive O2N-tridentate analogs apparently cannot do so.

Endostatin regulates branching morphogenesis of renal epithelial cells and ureteric bud.

Endostatin (ES) inhibits endothelial cell migration and has been found to bind to glypicans (Gpcs) on both endothelial cells and renal epithelial cells. We examined the possibility that ES might regulate epithelial cell morphogenesis. The addition of ES to cultured epithelial cells causes an inhibition of both hepatocyte growth factor- and epidermal growth factor-dependent process formation and migration. In contrast, ES does not inhibit epidermal growth factor-dependent morphogenesis in renal epithelial cells derived from Gpc-3 -/mice, whereas expression of Gpc-1 in these cells reconstitutes ES responsiveness. Gpc-3 -/mice have been shown to display enhanced ureteric bud (UB) branching early in development, and cultured UB cells release ES into the media, suggesting that ES binding to Gpcs may regulate UB branching. The addition of ES inhibits branching of the explanted UB, whereas a neutralizing Ab to ES enhances UB outgrowth and branching. Thus, local expression of ES at the tips of the UB may play a role in the regulation of UB arborization.

Levamisole vs. cyclophosphamide for frequently-relapsing steroid-dependent nephrotic syndrome.

A retrospective analysis comparing the first-time use of levamisole (L) or cyclophosphamide (C) as second-line therapy for children with frequently relapsing, steroid-dependent (FR/SD) nephrotic syndrome, was conducted at our center. The relapse rate and the total cumulative dose of prednisone during the year prior to L/C therapy was compared to that during the year following the institution of therapy with L or C in 51 patients, between July 1992 and June 1997. An analysis of covariance was used to adjust the outcome for differences between the 2 groups of treatment in the year prior to second-line drug initiation. In the L group the mean relapse rate was lowered by 0.28 relapses/patient/month and the mean cumulative dose of prednisone was reduced by 336 mg/m2/month versus 0.32 relapses/patient/month and 387 mg/m2/month in the C group (p = 0.395. p = 0.577). No significant difference in the effectiveness of L vs. C for therapy of FR/SD nephrotic syndrome could be identified in our patients. We conclude that L may be considered an alternative for C as a first second-line agent for these patients.

Glypicans and the biology of renal malformations.

The molecular mechanisms that control renal development are largely undefined. The discovery of mutations in the gene encoding glypican-3 (Gpc3) in humans with Simpson-Golabi-Behmel syndrome (SGBS) and renal dysplasia, and the establishment of a genetic mouse model of GPC3 deficiency has provided an opportunity to define the role of GPC3 during renal development. Glypicans are a family of cell surface heparan sulfate proteoglycans that control growth factor signalling in nonrenal tissues. Mutational inactivation of Gpc3 causes somatic overgrowth and cystic renal dysplasia, as observed in SGBS. Overgrowth of the ureteric bud and its branches and increased ureteric bud cell proliferation is observed during the early stages of renal development. Subsequently, during corticomedullary differentiation, cortical collecting duct cell proliferation is increased, while medullary collecting duct cells proliferate at a reduced rate and undergo apoptosis resulting in degeneration of the medulla. However, cells that constitute medullary cysts are characterized by enhanced cell proliferation and a lower rate of apoptosis. Thus, the phenotype arising from Gpc3 inactivation demonstrates that tight regulation of cell proliferation and apoptosis is critical during formation of the renal medulla.

Glypican-3 modulates BMP- and FGF-mediated effects during renal branching morphogenesis.

The kidney of the Gpc3-/ mouse, a novel model of human renal dysplasia, is characterized by selective degeneration of medullary collecting ducts preceded by enhanced cell proliferation and overgrowth during branching morphogenesis. Here, we identify cellular and molecular mechanisms underlying this renal dysplasia. Glypican-3 (GPC3) deficiency was associated with abnormal and contrasting rates of proliferation and apoptosis in cortical (CCD) and medullary collecting duct (MCD) cells. In CCD, cell proliferation was increased threefold. In MCD, apoptosis was increased 16-fold. Expression of Gpc3 mRNA in ureteric bud and collecting duct cells suggested that GPC3 can exert direct effects in these cells. Indeed, GPC3 deficiency abrogated the inhibitory activity of BMP2 on branch formation in embryonic kidney explants, converted BMP7-dependent inhibition to stimulation, and enhanced the stimulatory effects of KGF. Similar comparative differences were found in collecting duct cell lines derived from GPC3-deficient and wild type mice and induced to form tubular progenitors in vitro, suggesting that GPC3 directly controls collecting duct cell responses. We propose that GPC3 modulates the actions of stimulatory and inhibitory growth factors during branching morphogenesis.

Verotoxin targets lymphoma infiltrates of patients with post-transplant lymphoproliferative disease.

Post-transplant lymphoproliferative disease (PTLD) is an invasive, EBV expressing B lymphoma and a major cause of morbidity and mortality following organ transplantation. Presently there is limited therapy available; rather the patient often loses the allograft or succumbs to the malignancy. CD77 (or globotriaosyl ceramide -Gb(3)) is a germinal center B cell marker [Gregory et al. Int J Cancer 1998;42:213-20; Gregory et al., J Immunol 1987;139:313-8; Mangeney et al. Eur J Immunol 1991;21:1131-40], expressed on most EBV infected B cells and is the receptor for the E. coli derived verotoxin (VT) [Lingwood CA. Advances in Lipid Research 1993;25:189-212]. We present the basis of a possible novel approach to PTLD therapy utilizing the specific targeting of VT to the infiltrating lymphoma cells. Biopsies of adenoid, kidney or liver tissue of four PTLD patients were stained with verotoxin to determine expression of CD77. VT is a potent inducer of necrosis/apoptosis of receptor positive cells. In each PTLD case, the infiltrating EBV positive B lymphoma cells were strongly and selectively stained with VT, identifying CD77 as a new marker for these cells. For such individuals, VT might provide the basis of an approach to control their malignancy.

Bell palsy complicating pregnancy: a review.

UNLABELLED: The aim of the present work was to review the published evidence on the association of Bell palsy (BP), an acute idiopathic peripheral facial paralysis of unknown etiology, with pregnancy. Reports have shown that women of reproductive age are affected two to four times more often than men of the same age, and pregnant women 3.3 times more often than nonpregnant women. The apparent predisposition of pregnant women to Bell palsy has been attributed to the high extracellular fluid content, viral inflammation, and immunosuppression characteristic of pregnancy, but findings are controversial. Most cases of Bell palsy occur in the third trimester or the puerperium. Onset is acute and painful. Some authors suggest that Bell palsy increases the risk of hypertension and toxemia of pregnancy, whereas the pregnant state, in turn, may affect the course and severity of disease. Recovery is usually good; poor prognostic markers are recurrence in subsequent pregnancy and bilateral disease, both of which are rare. Neonatal outcome is apparently unaffected, although this has been studied rarely. The preferred mode of management remains undecided; it is usually confined to supportive care. Corticosteroids in pregnancy are controversial. We think clinicians should be aware of these findings to avoid unnecessary testing and treatment and to help the patient cope with this acute, painful disease. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians LEARNING OBJECTIVES: After completion of this article, the reader will be able to identify the potential etiologies of Bell palsy associated with pregnancy and to describe the clinical presentation of this condition in pregnancy and its likelihood for recovery.

Vesicoureteric reflux associated with renal dysplasia in the Wolf-Hirschhorn syndrome.

Wolf-Hirschhorn syndrome (WHS) is caused by a partial deletion of the short arm of chromosome 4 (4p16.3) and is characterized by severe pre- and postnatal growth retardation, developmental delay, and multiple congenital anomalies, including malformations of the urogenital system. We describe the renal and urinary tract phenotype in a series of six children with WHS. Vesicoureteric reflux was present in four of our six patients (5 of 10 ureters), an abnormality not previously reported in WHS.

[The Zavanelli maneuver--back to the womb].

The Zavanelli maneuver is the manual replacement of a partially-born fetus due to severe shoulder dystocia. It is described in obstetrical textbooks as being among the last to be tried in a series of maneuvers to rescue the fetus with severe shoulder dystocia, as it is considered a very difficult and heroic maneuver. Few obstetricians have seen it and fewer have done it themselves. It is even more rare when a single obstetrician has done the Zavanelli maneuver repeatedly. Therefore, both experienced obstetricians and certainly young residents are fearful when they have to use this maneuver and can lose control in cases of shoulder dystocia. We have found descriptions of 93 cases of use of the Zavanelli maneuver in vertex presentations. We also describe a recent case in our experience. We conclude that this maneuver is safe and not too difficult to perform even without previous experience. Fetal and maternal complications are few, but there is of course a bias against reporting bad results. We recommend that every obstetrician become familiar with this maneuver so as to feel sure that it is safe for him to use in severe cases of shoulder dystocia.

Prediction of perinatal outcome in fetuses suspected to have intrauterine growth restriction: Doppler US study of fetal cerebral, renal, and umbilical arteries.

PURPOSE: To determine and compare the diagnostic performance of fetal middle cerebral (MCA), renal (RA), and umbilical (UA) arterial Doppler ultrasonography (US) for prediction of adverse perinatal outcome in suspected intrauterine growth restriction (IUGR). MATERIALS AND METHODS: Two hundred ninety-three small-for-gestational age fetuses (24-39 weeks at recruitment and US-estimated weight or abdominal circumference below 10th percentile) were prospectively examined with Doppler US of the UA, MCA, and RA. Clinicians were blinded to MCA and RA Doppler measurements. RESULTS: Seventy-six fetuses (25.9%) had at least one major or minor adverse perinatal outcome. Major outcomes included stillbirth, neonatal death, neurologic complication, and necrotizing enterocolitis. The MCA pulsatility index (PI), compared with the UA PI and RA PI, was more sensitive (72.4% vs 44.7% and 8.3%) but less specific (58.1% vs 86.6% and 92.6%) in predicting adverse outcome. The UA PI had the highest positive likelihood ratio (ratio, 3.3); the MCA PI had the lowest negative likelihood ratio (ratio, 0.48). When gestational age at the first Doppler US examination was less than 32 weeks, the MCA PI had a sensitivity of 95.5% and negative predictive value of 97.7% for major adverse outcome (negative likelihood ratio, 0.10). CONCLUSION: In suspected IUGR, while an abnormal UA PI is a better predictor of adverse perinatal outcome than an abnormal MCA or RA PI, a normal MCA PI may help to identify fetuses without major adverse perinatal outcome, especially before 32 weeks gestational age.

Protein kinase A is a negative regulator of renal branching morphogenesis and modulates inhibitory and stimulatory bone morphogenetic proteins.

Protein kinase A (PKA) regulates morphogenetic responses to bone morphogenetic proteins (BMPs) during embryogenesis. However, the mechanisms by which PKA regulates BMP function are unknown. During kidney development, BMP-2 and high doses of BMP-7 inhibit branching morphogenesis, whereas low doses of BMP-7 are stimulatory (Piscione, T. D., Yager, T. D., Gupta, I. R., Grinfeld, B., Pei, Y., Attisano, L., Wrana, J. L., and Rosenblum, N. D. (1997) Am. J. Physiol. 273, F961-F975). We examined the interactions between PKA and these BMPs in embryonic kidney explants and in the mouse inner medullary collecting duct-3 model of collecting duct morphogenesis. H-89, an inhibitor of PKA, stimulated branching morphogenesis and enhanced the stimulatory effect of low doses of BMP-7 on tubule formation. Furthermore, H-89 rescued the inhibition of tubulogenesis by BMP-2 (or high doses of BMP-7) by attenuating BMP-2-induced collecting duct apoptosis. In contrast, 8-bromo-cAMP, an activator of PKA, inhibited tubule formation and attenuated the stimulatory effects of low doses of BMP-7. To determine mechanisms underlying the interdependence of BMP signaling and PKA activity, we examined the effect of PKA on the known signaling events in the BMP-2-dependent Smad1 signaling pathway and the effect of BMP-2 on PKA activity. PKA did not induce endogenous Smad1 phosphorylation, Smad1-Smad4 complex formation, or Smad1 nuclear translocation. In contrast, BMP-2 increased endogenous PKA activity and induced phosphorylation of the PKA effector, cAMP-response element-binding protein, in a PKA-dependent manner. We conclude that BMP-2 induces activation of PKA and that PKA regulates the effects of BMPs on collecting duct morphogenesis without activating the known signaling events in the BMP-2-dependent Smad1 signaling pathway.

Glypican-3-deficient mice exhibit developmental overgrowth and some of the abnormalities typical of Simpson-Golabi-Behmel syndrome.

Glypicans are a family of heparan sulfate proteoglycans that are linked to the cell surface through a glycosyl-phosphatidylinositol anchor. One member of this family, glypican-3 (Gpc3), is mutated in patients with the Simpson-Golabi-Behmel syndrome (SGBS). These patients display pre- and postnatal overgrowth, and a varying range of dysmorphisms. The clinical features of SGBS are very similar to the more extensively studied Beckwith-Wiedemann syndrome (BWS). Since BWS has been associated with biallelic expression of insulin-like growth factor II (IGF-II), it has been proposed that GPC3 is a negative regulator of IGF-II. However, there is still no biochemical evidence indicating that GPC3 plays such a role.Here, we report that GPC3-deficient mice exhibit several of the clinical features observed in SGBS patients, including developmental overgrowth, perinatal death, cystic and dyplastic kidneys, and abnormal lung development. A proportion of the mutant mice also display mandibular hypoplasia and an imperforate vagina. In the particular case of the kidney, we demonstrate that there is an early and persistent developmental abnormality of the ureteric bud/collecting system due to increased proliferation of cells in this tissue element. The degree of developmental overgrowth of the GPC3-deficient mice is similar to that of mice deficient in IGF receptor type 2 (IGF2R), a well characterized negative regulator of IGF-II. Unlike the IGF2R-deficient mice, however, the levels of IGF-II in GPC3 knockouts are similar to those of the normal littermates.

Domain-structured N1,N2-derivatized hydrazines as inhibitors of ribonucleoside diphosphate reductase: redox-cycling considerations.

Eight analogues of 1-[5-halogenosalicylidene]-2-[2'-pyridinoyl]hydrazine and -[2'-pyridyl]hydrazine, four of 1-[pyridoxylidene]-2-[2'-pyridinoyl]hydrazine, seven of 1-[pyridoxylidene]-2-[2'-pyridyl]hydrazine, and one each of 1, 2-bis[pyridoxylidene]diaminoethane and bis[pyridoxylidenehydrazino]phthalazine were synthesized. Their solutions in DMF were assayed for activity against the metalloenzyme ribonucleoside diphosphate reductase (RdR), prepared from a subcutaneously growing murine tumor (sarcoma 180) implanted in B6D2F3 male mice. The 14C-labeled CDP reductase was assayed by the modified method of Takeda and Weber, in which [14C]cytidine was separated from deoxycytidine by thin-layer chromatography (TLC) on cellulose foil. Distribution of radioactivity was assessed with an automatic TLC linear analyzer. Of the 31 compounds tested, 13 were essentially inactive, 7 were highly active against RdR, and the remaining 20 were slightly more active than hydroxyurea (used as a reference compound). The mechanism of inhibition is discussed in terms of three alternative pathways, initiated by sequestration of iron embedded in the R1 subunit of the metalloenzyme to form a C-centered chelate radical (via redox cycling). Alternatively, the latter could either reduce the tyrosyl radical or intercept radicals generated in the reduction process.

Umbilical artery blood flow velocity in pregnancies complicated by systemic lupus erythematosus.

PURPOSE: We evaluated the role of umbilical artery Doppler velocimetry in the surveillance of pregnancies complicated by systemic lupus erythematosus (SLE). METHODS: We retrospectively studied 56 women with SLE whose pregnancies were managed at our perinatal center between 1988 and 1995. RESULTS: Absent or reversed end-diastolic flow velocity was detected in 6 (11%) of 56 patients. This sub-group of patients had an increased risk of pre-eclampsia, intrauterine growth restriction, cesarean section, and preterm delivery. CONCLUSIONS: A high incidence (11%) of abnormal umbilical artery waveforms was detected. This finding was associated with an increased risk of maternal and fetal complications.

Effects of erythromycin on contractility of isolated myometrium from pregnant rats.

OBJECTIVE: Erythromycin is a stimulant of motor activity in the stomach, but its effects on the uterus have not been studied and only its antibiotic properties have been considered in the treatment of idiopathic preterm labor. The objective of this study was to characterize in vitro the effect of erythromycin on the contractility of the pregnant rat uterus. STUDY DESIGN: Myometrial strips from pregnant rats were suspended in tissue baths Isometric contractions were monitored by force transducers in response to various agents that were added to the bath solution. RESULTS: Erythromycin exposure caused a sustained decrease in phasic contractions induced by oxytocin or carbachol. This effect started at 0.01 mmol/L. At 1 mmol/L erythromycin reduced the contractions amplitude to 22% of the control and the frequency was reduced to 38% of control. CONCLUSION: We conclude that erythromycin produces a decrease in the pregnant rat myometrial activity in vitro, independent of the stimulant.