Safety and Outcomes of using ureteric access sheath (UAS) for treatment of Pediatric renal stones: Outcomes from 2 tertiary endourology centers.

OBJECTIVE: To look at the safety and outcomes of using ureteral access sheath (UAS) for pediatric renal stones. The use of UAS is variable in urological practice with very little clinical work on their use in pediatric kidney stone disease. PATIENTS AND METHODS: Data was retrospectively collected from 2 large European tertiary endourology centers for all pediatric patients (≤16 years) with renal stones who underwent flexible ureteroscopy and lasertripsy (FURSL) via UAS. Data was collected on patient details, stone demographics and clinical outcomes of the FURSL procedure. RESULTS: Forty-eight patients with a mean age of 10.7 years were treated with FURSL for a mean single and cumulative stone size of 10.4 mm and 15 mm respectively, with two-third having multiple stones and stones in the lower pole. The initial and final stone free rate (SFR) was 66.7% and 100% respectively with 1.3 procedures/patient. One patient each had intra-operative grade 1 ureteric injury and post-operative UTI, with no other injuries or complications noted. Over a mean follow-up of 17 months, no other complications were noted. CONCLUSION: Ureteral access sheath is safe for treatment of pediatric renal stones with excellent outcomes and are especially useful for larger or multiple stones. While there does not seem to be any medium-term sequalae, to avoid risk of ureteral injury, we would suggest using the smallest size sheath possible. We would argue these procedures are best done in specialist high-volume endourology units for optimal results.

Videolaparoscopic lower pole heminephrectomy for treatment of a duplex kidney.

INTRODUCTION: In a duplicated renal collecting system, or duplex kidney, the most frequent pathology presenting at the lower pole is the vesicoureteral reflux (VUR), which could lead to urinary tract infections (UTI) or even renal dysplasia. Under some circumstances, such as recurrent UTIs or impaired kidney function, heminephrectomy of the pathologic moiety is indicated. However, there are only few academic videos of laparoscopic lower pole heminephrectomy in the pediatric population available in literature. Therefore, we present a descriptive video of this procedure. METHODS: This video exhibits a case report of a 15-month-old male patient who underwent a videolaparoscopic lower pole heminephrectomy as treatment of a refluxing non-functional lower moiety of a right duplex kidney. Moreover, the patient presented a refluxing contralateral ureter which was endoscopically corrected at the same time. RESULTS: A laparoscopic right lower pole heminephrectomy associated with an endoscopic contralateral reflux treatment was performed. No complication occurred during hospital stay or at 30-day follow up. CONCLUSION: Videolaparoscopic lower pole heminephrectomy is a safe and feasible procedure in the pediatric population. Associating an endoscopic correction of the contralateral side reflux at the same moment shows no additional morbidity or complication.

Testing the role of sensory systems in the migratory heading of a songbird.

The identification of the sensory cues and mechanisms by which migratory birds are able to reach the same breeding and wintering grounds year after year has eluded biologists despite more than 50 years of intensive study. While a number of environmental cues have been proposed to play a role in the navigation of birds, arguments still persist about which cues are essential for the experience based navigation shown by adult migrants. To date, few studies have tested the sensory basis of navigational cues used during actual migration in the wild: mainly laboratory based studies or homing during the non-migratory season have been used to investigate this behaviour. Here we tested the role of olfactory and magnetic cues in the migration of the catbird (Dumetella carolinensis) by radio tracking the migration of birds with sensory manipulations during their actual migratory flights. Our data suggest that adult birds treated with zinc sulphate to produce anosmia were unable to show the same orientation as control adults, and instead reverted to a direction similar to that shown by juveniles making their first migration. The magnetic manipulation had no effect on the orientation of either adults or juveniles. These results allow us to propose that the olfactory sense may play a role in experience based migration in adult catbirds. While the olfactory sense has been shown to play a role in the homing of pigeons and other birds, this is the first time it has been implicated in migratory orientation.

[Identification and characterization of the first Spanish familial ligand-defective apolipoprotein B homozygote]. / Identificación y caracterización del primer español con defecto homocigoto familiar de unión de la apolipoproteína B.

BACKGROUND: Familial ligand-defective apolipoprotein B 100 (FDB) is an autosomal inherited disease due to mutations on apo B 100, clinically indistinguishable from familial hypercholesterolemia (FH). We described the first Spanish homozygote for FDB. METHODS: We have screened R3500Q mutation of apo B gene (PCR-SSCP analysis) in a large family with FDB and have identified the first Spanish homozygote for FDB. RESULTS: The homozygote is a 58 year-old man with coronary heart disease, no presence of xanthomata and with total cholesterol and LDL cholesterol plasma levels of 415 and 352 mg/dl. The response to statins and resins was up to 42% for total cholesterol and 51% for LDLc plasma values. The LDL receptor activity was normal in the FDB homozygote. CONCLUSIONS: We have identified and characterised the first Spanish homozygote for FDB (R3500Q mutation). Our data indicate a moderate lipoprotein phenotype in FDB homozygote, different as expected comparing to homozygous FH.

Electrothermal atomic absorption spectrometric diagnosis of familial hypercholesterolemia.

We have developed a new nonradioactive assay to identify human low-density lipoprotein receptor defects. It is based on the incubation of cultured cells with colloidal gold-LDL conjugates and quantitation of the gold associated with the cells by electrothermal atomic absorption spectrometry. After an oxidative treatment with nitric and hydrochloric acids, the biological matrix interferes neither with the gold recovery nor with the gold measurements, which are linear, at least from 0.15 to 3 ng of gold. When cells expressing a functional LDL receptor are incubated with increasing amounts of colloidal-gold LDL conjugates, the obtained saturation curve parallels that described when [125I]LDL is used as ligand. Moreover, this new assay allows us to clearly distinguish among fibroblasts from normal subjects or from heterozygous or homozygous patients of familial hypercholesterolemia, a very common autosomal disease. The assay is easy to perform, is sensitive, and avoids the use of radioactive compounds. Therefore, it could be successfully employed in the clinical diagnosis of this disease. Furthermore, since the methodology developed here can be applied to quantify the association of other gold-conjugated ligands to cells, it could have a widespread use in a variety of clinical and basic research studies.

Import of a cytosolic protein into lysosomes by chaperone-mediated autophagy depends on its folding state.

We have analyzed the folding state of cytosolic proteins imported in vitro into lysosomes, using an approach originally developed by Eilers and Schatz, (Eilers, M., and Schatz, G. (1986) Nature 322, 228-232) to investigate protein import into mitochondria. The susceptibility toward proteases of mouse dihydrofolate reductase (DHFR), synthesized in a coupled transcription-translation system with rabbit reticulocytes, decreased in the presence of its substrate analogue, methotrexate. This analogue complexes with high affinity with the in vitro synthesized DHFR and locks it into a protease-resistant folded conformation. DHFR was taken up by freshly isolated rat liver lysosomes and methotrexate reduced this uptake by about 80%. A chimeric DHFR protein, which carries the N-terminal presequence of subunit 9 of ATP synthase preprotein from Neurospora crassa fused to its N terminus, was taken up by lysosomes more efficiently. Again, methotrexate abolished the lysosomal uptake of the fusion protein, which was partially restored by washing of methotrexate from DHFR or by adding together methotrexate and dihydrofolate, the natural substrate of DHFR. Immunoblot analysis with anti-DHFR of liver lysosomes and of other fractions, isolated from rats starved for 88 h and treated with lysosomal inhibitors, suggests that DHFR is degraded by chaperone-mediated autophagy. Competition with ribonuclease A and stimulation by ATP/Mg(2+) and the heat shock cognate protein of 73 kDa show that the lysosomal uptake of the fusion protein also occurs by this pathway. It is concluded that the lysosomal uptake of cytosolic proteins by chaperone-mediated autophagy mainly occurs by passage of the unfolded proteins through the lysosomal membrane. Therefore, this mechanism is different from protein transport into peroxisomes, but similar to the import of proteins into the endoplasmic reticulum and mitochondria.

Subcellular localization of proteasomes and their regulatory complexes in mammalian cells.

Proteasomes can exist in several different molecular forms in mammalian cells. The core 20S proteasome, containing the proteolytic sites, binds regulatory complexes at the ends of its cylindrical structure. Together with two 19S ATPase regulatory complexes it forms the 26S proteasome, which is involved in ubiquitin-dependent proteolysis. The 20S proteasome can also bind 11S regulatory complexes (REG, PA28) which play a role in antigen processing, as do the three variable gamma-interferon-inducible catalytic beta-subunits (e.g. LMP7). In the present study, we have investigated the subcellular distribution of the different forms of proteasomes using subunit specific antibodies. Both 20S proteasomes and their 19S regulatory complexes are found in nuclear, cytosolic and microsomal preparations isolated from rat liver. LMP7 was enriched approximately two-fold compared with core alpha-type proteasome subunits in the microsomal preparations. 20S proteasomes were more abundant than 26S proteasomes, both in liver and cultured cell lines. Interestingly, some significant differences were observed in the distribution of different subunits of the 19S regulatory complexes. S12, and to a lesser extent p45, were found to be relatively enriched in nuclear fractions from rat liver, and immunofluorescent labelling of cultured cells with anti-p45 antibodies showed stronger labelling in the nucleus than in the cytoplasm. The REG was found to be localized predominantly in the cytoplasm. Three- to six-fold increases in the level of REG were observed following gamma-interferon treatment of cultured cells but gamma-interferon had no obvious effect on its subcellular distribution. These results demonstrate that different regulatory complexes and subpopulations of proteasomes have different distributions within mammalian cells and, therefore, that the distribution is more complex than has been reported for yeast proteasomes.

The Escherichia coli trmE (mnmE) gene, involved in tRNA modification, codes for an evolutionarily conserved GTPase with unusual biochemical properties.

The evolutionarily conserved 50K protein of Escherichia coli, encoded by o454, contains a consensus GTP-binding motif. Here we show that 50K is a GTPase that differs extensively from regulatory GTPases such as p21. Thus, 50K exhibits a very high intrinsic GTPase hydrolysis rate, rather low affinity for GTP, and extremely low affinity for GDP. Moreover, it can form self-assemblies. Strikingly, the 17 kDa GTPase domain of 50K conserves the guanine nucleotide-binding and GTPase activities of the intact 50K molecule. Therefore, the structural requirements for GTP binding and GTP hydrolysis by 50K are without precedent and justify a separate classification in the GTPase superfamily. Immunoelectron microscopy reveals that 50K is a cytoplasmic protein partially associated with the inner membrane. We prove that o454 is allelic with trmE, a gene involved in the biosynthesis of the hypermodified nucleoside 5-methylaminomethyl-2-thiouridine, which is found in the wobble position of some tRNAs. Our results demonstrate that 50K is essential for viability depending on the genetic background. We propose that combination of mutations affecting the decoding process, which separately do not reveal an obvious defect in growth, can give rise to lethal phenotypes, most likely due to synergism.

Import into and degradation of cytosolic proteins by isolated yeast vacuoles.

In eukaryotic cells, both lysosomal and nonlysosomal pathways are involved in degradation of cytosolic proteins. The physiological condition of the cell often determines the degradation pathway of a specific protein. In this article, we show that cytosolic proteins can be taken up and degraded by isolated Saccharomyces cerevisiae vacuoles. After starvation of the cells, protein uptake increases. Uptake and degradation are temperature dependent and show biphasic kinetics. Vacuolar protein import is dependent on cytosolic heat shock proteins of the hsp70 family and on protease-sensitive component(s) on the outer surface of vacuoles. Degradation of the imported cytosolic proteins depends on a functional vacuolar ATPase. We show that the cytosolic isoform of yeast glyceraldehyde-3-phosphate dehydrogenase is degraded via this pathway. This import and degradation pathway is reminiscent of the protein transport pathway from the cytosol to lysosomes of mammalian cells.

An algorithm for detecting features of the hormone profiles of the human menstrual cycle.

An algorithm for detecting features of the cycles of the gonadotropic and ovarian hormones in women is described. The algorithm can detect hormone peaks and normal cycles defined in terms of the peaks in sequences of measurements that have an arbitrary starting point in the menstrual cycle and are of arbitrary length. The algorithm makes use of fuzzy set theory and is optimized using signal detection theory.

Measuring endocrine profiles of women in field studies.

Improved methods are needed to evaluate the effects of occupational and environmental hazards on the reproductive health of human female populations. This communication describes highly specific, sensitive, and reliable time-resolved fluorescence immunoassays for measuring luteinizing hormone (LH) and follicle-stimulating hormone (FSH), estrone 3-glucuronide (E13G), and pregnanediol 3-glucuronide (Pd3G) in urine, a fluid that is convenient and painless to collect serially from large populations. Furthermore, some of the technical issues relevant to the successful application of these measurements to field studies are discussed.

A rapid procedure suitable to assess quantitatively the endocytosis of colloidal gold and its conjugates in cultured cells.

We measured the endocytic uptake of low-density lipoproteins (LDLs) conjugated to colloidal gold in cultured cells, either by counting gold particles on electron micrographs or by inductively coupled plasma (ICP) mass spectrometry (MS). Both procedures are comparable but the latter requires a considerably shorter time and allows analysis of a much larger sample. In addition, ICP MS, compared to alternative radioactive or fluorescent procedures, offers the major advantage of using the same probe to quantify the endocytic uptake and to follow it by electron microscopy. Therefore, ICP MS analysis provides an easy, rapid, and sensitive quantification of endocytosis that complements the electron microscopic studies.

A negative regulatory function for the protein tyrosine phosphatase PTP2C revealed by reconstruction of platelet-derived growth factor receptor signalling in Schizosaccharomyces pombe.

We have exploited reconstitution in the fission yeast Schizosaccharomyces pombe to investigate how activation of phospholipase Cgamma (PLCgamma) by the platelet-derived growth factor-beta receptor (PDGFbetaR) is regulated by the SH2 domain-containing protein tyrosine phosphatase PTP2C (also known as SHP-2). When co-expressed in S. pombe, PTP2C abolished PDGFbetaR autophosphorylation as well as its ability to phosphorylate and activate PLCgamma. Inhibition of PDGFbetaR signalling by PTP2C appears specific insofar that PTPIC, a close homologue of PTP2C, does not suppress activation of either PDGFbetaR or PLCgamma. Surprisingly, an inactive PTP2C mutant (C459S), which dephosphorylates neither PDGFbetaR nor PLCgamma, remains fully effective as an inhibitor of [3H]inositol phosphate generation indicating that negative regulation is at least in part independent of catalytic activity. This contrasts with PLCgamma activation by c-Src which, although blocked by active PTP2C, is not inhibited by the mutant PTP2C C459S. These observations indicate that in addition to a reported positive role relaying trophic signals, PTP2C can also exert a negative effect on the PDGFbetaR and its signalling to PLCgamma.

Detecting pre-ovulatory luteinizing hormone surges in urine.

The study objectives were to determine (i) if pre-ovulatory luteinizing hormone (LH) surges, undetected in urine by two immunoradiometric assays (IRMA), were detectable by an ultrasensitive immunofluorometric assay (IFMA) and (ii) the influence of creatinine adjustment on the detection and timing of the urinary LH surges. Daily urine specimens were contributed by healthy 25-36 year old volunteers during 14 ovulatory menstrual cycles for an epidemiological study conducted in 1983-1985. Specimens were selected as having been previously assayed by two IRMA without consistently detecting LH surges. These urine specimens were remeasured using an IFMA and adjusted for creatinine concentration. IFMA measurements revealed unambiguous LH surges in all cycles. Adjusting IRMA urinary LH values for creatinine concentrations revealed previously undetected LH surges in four of eight cycles. Creatinine adjustment also altered the timing of IRMA and IFMA LH surges by 1-5 days. These results demonstrate an IFMA that detects pre-ovulatory LH surges in unpreserved, frozen urine from cycles where such surges were previously undetectable. Further, creatinine adjustment can markedly affect detection and timing of the onset and peak of the urinary LH surge. While our analysis suggests that this adjustment improves the validity of the LH measure, this requires further investigation.

Bcl-2 undergoes phosphorylation by c-Jun N-terminal kinase/stress-activated protein kinases in the presence of the constitutively active GTP-binding protein Rac1.

We have studied the phosphorylation of the Bcl-2 family of proteins by different mitogen-activated protein (MAP) kinases. Purified Bcl-2 was found to be phosphorylated by the c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) p54-SAPKbeta, and this is specific insofar as the extracellular signal-regulated kinase 1 (ERK1) and p38/RK/CSBP (p38) catalyzed only weak modification. Bcl-2 undergoes similar phosphorylation in COS-7 when coexpressed together with p54-SAPKbeta and the constitutive Rac1 mutant G12V. This is seen by both 32PO4 labeling and the appearance of five discrete Bcl-2 bands with reduced gel mobility. As anticipated, both intracellular p54-SAPKbeta activation and Bcl-2 phosphorylation are blocked by co-transfection with the MAP kinase specific phosphatase MKP3/PYST1. MAP kinase specificity is also seen in COS-7 cells as Bcl-2 undergoes only weak phosphorylation when co-expressed with enzymatically activated ERK1 or p38. Four critical residues undergoing phosphorylation in COS-7 cells were identified by expression of the quadruple Bcl-2 point mutant T56A,S70A,T74A, S87A. Sequencing phosphopeptides derived from tryptic digests of Bcl-2 indicates that purified GST-p54-SAPKbeta phosphorylates identical sites in vitro. This is the first report of Bcl-2 phosphorylation by the JNK/SAPK class of MAP kinases and could indicate a key modification allowing control of Bcl-2 function by cell surface receptors, Rho family GTPases, and/or cellular stresses.

A population of rat liver lysosomes responsible for the selective uptake and degradation of cytosolic proteins.

Two populations of rat liver lysosomes can be distinguished on the basis of their density. A major difference between these populations is that one contains the heat shock cognate protein of 73 kDa (hsc73) within the lysosomal lumen. The lysosomal fraction containing hsc73 exhibits much higher efficiencies in the in vitro uptake and degradation of glyceraldehyde-3-phosphate dehydrogenase and ribonuclease A, two well established substrates of the selective lysosomal pathway of intracellular protein degradation. Preloading of the lysosomal population that is devoid of lumenal hsc73 with hsc73 isolated from cytosol activated the selective transport of substrate proteins into these lysosomes. Furthermore, treatment of animals with leupeptin, an inhibitor of lysosomal cathepsins, or 88 h of starvation also increased the amount of hsc73 within their lysosomal lumen, and these in vivo treatments also activated the selective transport of substrate proteins in vitro. Thus, the hsc73 located within lysosomes appears to be required for efficient uptake of cytosolic proteins by these organelles. The difference in hsc73 content between the lysosomal populations appears to be due to differences in their ability to take up hsc73 combined with differences in the intralysosomal degradation rates of hsc73. The increased stability of hsc73 in one population of lysosomes is primarily a consequence of this lysosomal population's more acidic pH.

Acidic cytosolic proteins are preferentially imported into rat liver lysosomes.

Previous studies have reported that lysosomes isolated from human diploid fibroblasts and from rat liver can selectively import and degrade specific proteins. We have now reinvestigated this selectivity using an in vitro assay with rat liver lysosomes and an extract of cytosolic proteins prepared from cultured cells labeled to equilibriums with [35S-]methionine. Analysis by two-dimensional gel electrophoresis and autoradiography of the cytosolic proteins bound to the lysosomal membrane and imported into the lysosomes shows that when all cytosolic proteins are simultaneously present in the in vitro assay the lysosomal uptake also occurs in a specific manner. These findings suggest that isolated lysosomes are able to discriminate among different proteins, selecting those with certain features for lysosomal degradation. Additional characterization of the cytosolic proteins which are selectively imported by lysosomes shows that a common structural feature of most, but not all, of these proteins is an acidic isoelectric point (pI <6.0) and a small or intermediate size. This observation is in agreement with earlier studies which established a relationship between the in vivo half-lives of cytosolic proteins in rat liver and their net charge, with acidic proteins, in general, being degraded more rapidly than neutral or basic proteins. The reasons for this preference are still uncertain, although a possible explanation is presented.

Use of inductively coupled plasma-mass spectrometry for the quantitation of the binding and uptake of colloidal gold-low-density lipoprotein conjugates by cultured cells.

The binding and endocytic uptake of low-density lipoprotein (LDL) particles by cells, transiently or permanently transfected with the human LDL receptor cDNA, was investigated, under different situations, using colloidal gold-LDL conjugates. The amount of gold associated with the various cells, which bind and internalize LDL to different extents, was estimated by inductively coupled plasma-MS. In all cases, the existing differences in LDL binding and uptake were clearly detectable with this procedure. We conclude, therefore, that inductively coupled plasma-MS provides an appropriate assay system for the rapid quantitation of these processes. This procedure also recognizes differences in LDL receptor expression in human lymphocytes and, therefore, it could be of value for the differential diagnosis of LDL receptor defects in familial hypercholesterolemia in various cell types. In addition, this easily performed methodology can also be applied to a variety of other problems requiring quantitation of colloidal gold associated with cells.

Selective uptake and degradation of c-Fos and v-Fos by rat liver lysosomes.

The transcription factor c-Fos is a short-lived protein and calpains and ubiquitin-dependent systems have been proposed to be involved in its degradation. In this report, we consider a lysosomal degradation pathway for c-Fos. Using a cell-free assay, we have found that freshly isolated lysosomes can take up and degrade c-Fos with high efficiency. v-Fos, the oncogenic counterpart of c-Fos, can also be taken up by lysosomes, yet the amount of incorporated protein is much lower. c-Fos uptake is independent of its phosphorylation state but it appears to be regulated by dimerization with differentially phosphorylated forms of c-Jun, while v-Fos escapes this regulation. Moreover, we show that c-Fos is immunologically detected in lysosomes isolated from the liver of rats treated with the protease inhibitor leupeptin. Altogether, these results suggest that lysosomes can also participate in the selective degradation of c-Fos in rat liver.