[Renal Trauma]. / Traumatismes du rein.

INTRODUCTION: Renal traumas are common, observed in 10% of patients with abdominal trauma. Most renal traumas are blunt, resulting from a direct hit or from an abrupt deceleration. MATERIAL AND METHODS: We realized a synthesis of renal trauma management for nurses. RESULTS: Clinical presentation often encompasses gross hematuria and lumbar pain. The best diagnostic tool is computed tomography (CT) urogram. Based on CT urogram images, renal traumas are classified according to the American Association for the Surgery of Trauma (AAST) classification in five grades of increasing severity. The management is conservative in the vast majority of cases and has been largely simplified over the past few years, being now mostly based on observation. Radiological interventional and endoscopic procedures are used only in very selected cases and surgical exploration has become extremely rare. CONCLUSION: The prognosis has also considerably improved and renal trauma rarely result in death or loss of the kidney nowadays.

SLK-mediated phosphorylation of paxillin is required for focal adhesion turnover and cell migration.

Focal adhesion turnover is a complex process required for cell migration. We have previously shown that the Ste20-like kinase (SLK) is required for cell migration and efficient focal adhesion (FA) turnover in a FA kinase (FAK)-dependent manner. However, the role of SLK in this process remains unclear. Using a candidate substrate approach, we show that SLK phosphorylates the adhesion adapter protein paxillin on serine 250. Serine 250 phosphorylation is required for paxillin redistribution and cell motility. Mutation of paxillin serine 250 prevents its phosphorylation by SLK in vitro and results in impaired migration in vivo as evidenced by an accumulation of phospho-FAK-Tyr397 and altered FA turnover rates. Together, our data suggest that SLK phosphorylation of paxillin on serine 250 is required for FAK-dependent FA dynamics.

The Ste20-like kinase SLK is required for ErbB2-driven breast cancer cell motility.

The Ste20-like kinase, SLK, is involved in the control of cell motility through its effects on actin reorganization and focal adhesion turnover. Here we investigated the role of SLK in chemotaxis downstream of the tyrosine kinase receptor, HER2/ErbB2/Neu, which is frequently overexpressed in human breast cancers. Our results show that SLK is required for the efficient cell migration of human and mouse mammary epithelial cell lines in the presence of the Neu activator, heregulin, as a chemoattractant. SLK activity is stimulated by heregulin treatment or by overexpression of activated Neu. Phosphorylation of tyrosine 1201 or tyrosines 1226/7 on Neu is a key event for SLK activation and cell migration, and cancer cell invasion mediated by these tyrosines is inhibited by kinase-inactive SLK. Signaling pathway inhibitors show that Neu-mediated SLK activation is dependent on MEK, PI3K, PLCgamma and Shc signaling. Furthermore, heregulin-stimulated SLK activity requires signals from the focal adhesion proteins, FAK and src. Finally, phospho-FAK analysis shows that SLK is required for Neu-dependent focal adhesion turnover. Together, these studies define an interaction between Neu and SLK signaling in the regulation of cancer cell motility.

Effect of liquid municipal biosolid application method on tile and ground water quality.

This study examined bacteria and nutrient quality in tile drainage and shallow ground water resulting from a fall land application of liquid municipal biosolids (LMB), at field application rates of 93,500 L ha(-1), to silt-clay loam agricultural field plots using two different land application approaches. The land application methods were a one-pass AerWay SSD approach (A), and surface spreading plus subsequent incorporation (SS). For both treatments, it took between 3 and 39 min for LMB to reach tile drains after land application. The A treatment significantly (p < 0.1) reduced application-induced LMB contamination of tile drains relative to the SS treatment, as shown by mass loads of total Kjeldahl N (TKN), NH(4)-N, Total P (TP), PO(4)-P, E. coli., and Clostridium perfringens. E. coli contamination resulting from application occurred to at least 2.0-m depth in ground water, but was more notable in ground water immediately beneath tile depth (1.2 m). Treatment ground water concentrations of selected nutrients and bacteria for the study period ( approximately 46 d) at 1.2-m depth were significantly higher in the treatment plots, relative to control plots. The TKN and TP ground water concentrations at 1.2-m depth were significantly (p < 0.1) higher for the SS treatment, relative to the A treatment, but there were no significant (p > 0.1) treatment differences for the bacteria. For the macroporous field conditions observed, pre-tillage by equipment such as the AerWay SSD, will reduce LMB-induced tile and shallow ground water contamination compared to surface spreading over non-tilled soil, followed by incorporation.

Cortical spreading depression transiently activates MAP kinases.

Cortical spreading depression (CSD) has been shown to have neuroprotective effects when administered in advance of cerebral ischemia. The mechanism by which CSD induces its neuroprotective effect however remains to be elucidated. Since MAP kinases have been shown to impart neuroprotection in ischemic preconditioning paradigms, we attempted to determine the role CSD may have in the activation of MAPK. We show that CSD is capable of increasing the phosphorylation of ERK in a MEK-dependent manner. This phosphorylation is, however, transient, as phosphorylated ERK levels return to control levels 45 min after 2 h of CSD elicitation. Immunohistochemical analysis reveals that the phosphorylated form of ERK is located ubiquitously in cells of the CSD-treated cortex while CSD-elicited MEK phosphorylation resides solely in the nuclei. These data suggest that CSD may act via the MAP kinase pathways to mediate preconditioning.

A two-hybrid system for transactivator bait proteins.

We describe a two-hybrid strategy for detection of interactions with transactivator proteins. This repressed transactivator (RTA) system employs the N-terminal repression domain of the yeast general repressor TUP1. TUP1-GAL80 fusion proteins, when coexpressed with GAL4, are shown to inhibit transcription of GAL4-dependent reporter genes. This effect requires the C-terminal 30 residues of GAL4, which are required for interaction with GAL80 in vitro. Furthermore, repression of GAL transcription by TUP1-GAL80 requires SRB10, demonstrating that the TUP1 repression domain, in the context of a two-hybrid interaction, functions by the same mechanism as endogenous TUP1. Using this strategy, we demonstrate interactions between the mammalian basic helix-loop-helix proteins MyoD and E12, and between c-Myc and Bin-1. We have also identified interacting clones from a TUP1-cDNA fusion expression library by using GAL4-VP16 as a bait fusion. These results demonstrate that RTA is generally applicable for identifying and characterizing interactions with transactivator proteins in vivo.

Pax7 is required for the specification of myogenic satellite cells.

The paired box transcription factor Pax7 was isolated by representational difference analysis as a gene specifically expressed in cultured satellite cell-derived myoblasts. In situ hybridization revealed that Pax7 was also expressed in satellite cells residing in adult muscle. Cell culture and electron microscopic analysis revealed a complete absence of satellite cells in Pax7(-/-) skeletal muscle. Surprisingly, fluorescence-activated cell sorting analysis indicated that the proportion of muscle-derived stem cells was unaffected. Importantly, stem cells from Pax7(-/-) muscle displayed almost a 10-fold increase in their ability to form hematopoietic colonies. These results demonstrate that satellite cells and muscle-derived stem cells represent distinct cell populations. Together these studies suggest that induction of Pax7 in muscle-derived stem cells induces satellite cell specification by restricting alternate developmental programs.

Myotonic dystrophy (DM) protein kinase levels in congenital and adult DM patients.

Myotonic dystrophy is caused by a (CTG)n trinucleotide repeat expansion located in the 3' untranslated region of the myotonic dystrophy protein kinase gene (DMPK). To date, the disease mechanism has proven elusive. The mutation would not be expected to affect kinase function and yet the disease is inherited in a dominant fashion. Mutant DMPK transcripts have been demonstrated to be retained in affected cell nuclei which could reduce DMPK protein levels and cause disease by haploinsufficiency. An alternate hypothesis is that the expansion confers a toxic gain of function on the transcript. In previous studies, various 52-55 kDa proteins have been detected using antisera targeted against DMPK and a decline of two of these candidates in disease tissues was reported. Current information now suggests that these proteins are not products of the myotonic dystrophy gene. We have characterised an antiserum which has been confirmed to recognise authentic 71 and 80 kDa isoforms of DMPK. Determination of the kinase levels in disease tissues with controls for patient age and tissue integrity demonstrates a modest overexpression in adult patients. In tissues from severely affected congenital patients only a slight decline is seen. This data argues against DMPK haploinsufficiency as a disease mechanism.

The molecular regulation of myogenesis.

Over the past years, several studies have unraveled important mechanisms by which the four myogenic regulatory factors (MRFs: MyoD, Myf-5, myogenin, and MRF4) control the specification and the differentiation of the muscle lineage. Early experiments led to the hypothesis that these factors were redundant and could functionally replace one another. However, recent experiments using in vivo and in vitro models have demonstrated that in fact different aspects of the myogenic program are controlled by different factors in vivo, suggesting that these factors play distinct roles during myogenesis. The activity of the MRFs during proliferation and differentiation of muscle precursor cells has clearly been demonstrated to be dependent on specific cell-cycle control mechanisms as well as distinct interactions with other regulatory molecules, such as the ubiquitously expressed E proteins and several other transcription factors. Furthermore, the observation that the MRFs can recruit chromatin remodeling proteins has shed some light on the mechanisms by which the MRFs activate gene expression. Recently, a functional role for MyoD during satellite cell activation and muscle repair has been identified in vivo, which cannot be substituted for by the other MRFs. This has put forward the hypothesis that these factors also play specific biological roles following muscle injury and repair.

Caspase 3 cleavage of the Ste20-related kinase SLK releases and activates an apoptosis-inducing kinase domain and an actin-disassembling region.

We have demonstrated that a novel Ste20-related kinase, designated SLK, mediates apoptosis and actin stress fiber dissolution through distinct domains generated by caspase 3 cleavage. Overexpression of SLK in C2C12 myoblasts stimulated the disassembly of actin stress fibers and focal adhesions and induced apoptosis, as determined by annexin V binding and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling analysis. SLK was cleaved by caspase 3 in vitro and in vivo during c-Myc-, tumor necrosis factor alpha, and UV-induced apoptosis. Furthermore, cleavage of SLK released two domains with distinct activities: an activated N-terminal kinase domain that promoted apoptosis and cytoskeletal rearrangements and a C-terminus domain that disassembled actin stress fibers. Moreover, our analysis has identified a novel conserved region (termed the AT1-46 homology domain) that efficiently promotes stress fiber disassembly. Finally, transient transfection of SLK also activated the c-Jun N-terminal kinase signaling pathway. Our results suggest that caspase-activated SLK represents a novel effector of cytoskeletal remodeling and apoptosis.

Induction of apoptosis by SLK, a Ste20-related kinase.

We have cloned and characterized a novel murine Ste20-related kinase designated SLK. SLK displays high homology to the Ste20-related kinase LOK, and is more distantly related to MST1 and 2, both Ste20-like kinases. In addition, SLK displays high homology to microtubule and nuclear associated protein (M-NAP) and AT1-46, both of unknown function. SLK is ubiquitously expressed as multiple mRNAs in tissues and cell lines and is downregulated by mitogen depletion in differentiating myoblasts. Biochemical characterization showed that SLK overexpression activates c-Jun amino-terminal kinase 1 (JNK1). However, in vitro kinase assays indicated that SLK was not activated in response to various growth factors or stress-inducing agents. Immunofluorescence studies revealed that SLK colocalized to distinct cytosolic domains, preferentially at the periphery of the cells. In addition, prolonged overexpression of SLK in cultured fibroblasts resulted in apoptosis as demonstrated by annexin-V and TUNEL staining. Our results suggest that SLK belongs to a new family of protein kinases, mediating activation of the stress response pathway through a novel signaling cascade.

Reduced differentiation potential of primary MyoD-/- myogenic cells derived from adult skeletal muscle.

To gain insight into the regeneration deficit of MyoD-/- muscle, we investigated the growth and differentiation of cultured MyoD-/- myogenic cells. Primary MyoD-/- myogenic cells exhibited a stellate morphology distinct from the compact morphology of wild-type myoblasts, and expressed c-met, a receptor tyrosine kinase expressed in satellite cells. However, MyoD-/- myogenic cells did not express desmin, an intermediate filament protein typically expressed in cultured myoblasts in vitro and myogenic precursor cells in vivo. Northern analysis indicated that proliferating MyoD-/- myogenic cells expressed fourfold higher levels of Myf-5 and sixfold higher levels of PEA3, an ETS-domain transcription factor expressed in newly activated satellite cells. Under conditions that normally induce differentiation, MyoD-/- cells continued to proliferate and with delayed kinetics yielded reduced numbers of predominantly mononuclear myocytes. Northern analysis revealed delayed induction of myogenin, MRF4, and other differentiation-specific markers although p21 was upregulated normally. Expression of M-cadherin mRNA was severely decreased whereas expression of IGF-1 was markedly increased in MyoD-/- myogenic cells. Mixing of lacZ-labeled MyoD-/- cells and wild-type myoblasts revealed a strict autonomy in differentiation potential. Transfection of a MyoD-expression cassette restored cytomorphology and rescued the differentiation deficit. We interpret these data to suggest that MyoD-/- myogenic cells represent an intermediate stage between a quiescent satellite cell and a myogenic precursor cell.

Teaching CAPD to the visually impaired.

The increasing number of patients on CAPD (continuous ambulatory peritoneal dialysis) offers multiple challenges to the home dialysis unit. During the last year we have changed our nursing practice and have successfully trained five visually impaired clients to perform CAPD exchanges utilizing a disconnect system without a helper or caregiver. In this article we will discuss the methods we used, the assist devices and the patient outcomes in our population. We measured our success in terms of peritonitis rate, adequacy of dialysis and lifestyle considerations for this population.

Definition of regulatory sequence elements in the promoter region and the first intron of the myotonic dystrophy protein kinase gene.

Myotonic dystrophy is the most common inherited adult neuromuscular disorder with a global frequency of 1/8000. The genetic defect is an expanding CTG trinucleotide repeat in the 3'-untranslated region of the myotonic dystrophy protein kinase gene. We present the in vitro characterization of cis regulatory elements controlling transcription of the myotonic dystrophy protein kinase gene in myoblasts and fibroblasts. The region 5' to the initiating ATG contains no consensus TATA or CCAAT box. We have mapped two transcriptional start sites by primer extension. Deletion constructs from this region fused to the bacterial chloramphenicol acetyltransferase reporter gene revealed only subtle muscle specific cis elements. The strongest promoter activity mapped to a 189-base pair fragment. This sequence contains a conserved GC box to which the transcription factor Sp1 binds. Reporter gene constructs containing a 2-kilobase pair first intron fragment of the myotonic dystrophy protein kinase gene enhances reporter activity up to 6-fold in the human rhabdomyosarcoma myoblast cell line TE32 but not in NIH 3T3 fibroblasts. Co-transfection of a MyoD expression vector with reporter constructs containing the first intron into 10 T1/2 fibroblasts resulted in a 10-20-fold enhancement of expression. Deletion analysis of four E-box elements within the first intron reveal that these elements contribute to enhancer activity similarly in TE32 myoblasts and 10 T1/2 fibroblasts. These data suggest that E-boxes within the myotonic dystrophy protein kinase first intron mediate interactions with upstream promoter elements to up-regulate transcription of this gene in myoblasts.

Overexpression of 3'-untranslated region of the myotonic dystrophy kinase cDNA inhibits myoblast differentiation in vitro.

The genetic defect underlying myotonic dystrophy (DM) has been identified as an unstable CTG trinucleotide repeat amplification in the 3'-untranslated region (3'-UTR) of the DM kinase gene (DMK). Individuals with the most severe congenital form display a marked delay in muscle terminal differentiation. To gain insight into the role of DMK during myogenesis, we have examined the effect of DMK overexpression on the terminal differentiation of the murine myoblast cell line C2C12. We demonstrate that a 4-10-fold constitutive overexpression of DMK mRNA in myoblasts caused a marked inhibition of terminal differentiation. Surprisingly, this activity was mapped to a 239-nucleotide region of the 3'-UTR of the DMK transcript. When the DMK 3'-UTR was placed downstream of a reporter gene, the same inhibition of myogenesis was observed. Following the induction of differentiation of myoblast clones overexpressing the DMK 3'-UTR, the levels of myogenin mRNA were reduced by approximately 4-fold, whereas the steady state levels of mef-2c transcripts were not affected. These data suggest that overexpression of the DMK 3'-UTR may interfere with the expression of musclespecific mRNAs leading to a delay in terminal differentiation.

Word fluency after a right-hemisphere lesion.

Joanette and Goulet (Neuropsychologia, 1986, 24, 875-879) reported that right-handed patients suffering from a right-hemisphere stroke were impaired on semantic but not on orthographic criteria when they were submitted to a word fluency task. The interpretation of this dissociation was that the right hemisphere would subtend a particular contribution to the semantic component of word processing in right handers. The goal of the research reported here was to challenge this dissociation. In contrast with the first study, the production criteria were presented randomly and their level of productivity was a controlled factor. The semantic-orthographic dissociation was not replicated under these conditions.

Investigation of myotonic dystrophy kinase isoform translocation and membrane association.

Myotonic dystrophy is caused by the expansion of a CTG repeat found in the 3'-untranslated region of the myotonic dystrophy kinase. The mechanism of disease and the role of the kinase are currently obscure. Here we begin the investigation of domain structure/function correlations to aid in determining its normal function. Expressed full-length protein and protein truncated before a C-terminal hydrophobic domain were compared. In vitro, signal peptide function and protection of kinase by microsomal membranes were absent; thus, it is not translocated, as previously proposed. However, full-length kinase expressed in insect cells was found in fractions enriched for membranes and decorated mitochondria. The truncated form was found primarily in the cytosol. The kinase was present as two self-associated, disulfide-linked complexes. The majority of full-length kinase was found in the larger of the two complexes, while almost all of the truncated form was found in the smaller. Thus, the C-terminal region confers a higher order of self-association. Furthermore, full-length kinase expressed in COS-1 cells was present as high molecular weight complex, while the truncated form was present as monomer species. These experiments indicate that the myotonic dystrophy kinase is not membrane-integrated, but that it may have a molecular organization which favors peripheral association with membranes.

Isolation of a novel G protein-coupled receptor (GPR4) localized to chromosome 19q13.3.

We present the cloning and sequencing of the human gene for a novel G-protein coupled receptor (GPR4), from the critical myotonic dystrophy (DM) region on chromosome 19q13.3. The homologous porcine gene was isolated and sequenced as well. The genes of both species are intronless and contain an open reading frame encoding a protein of 362 amino acids. In human, two isoforms of GPR4 are expressed, differing in their 3' untranslated region due to the use of alternate polyadenylation signals and measuring approximately 2.8 and 1.8 kb, respectively. Northern blot analysis showed that GPR4 is widely expressed, with higher levels in kidney, heart, and especially lung, where it is at least fivefold greater than in other tissues. Sequence analysis suggests that GPR4 is a peptide receptor and shares strongest homologies with purinergic receptors and receptors for angiotensin II, platelet activating factor, thrombin, and bradykinin.

Structure and genomic sequence of the myotonic dystrophy (DM kinase) gene.

The mutation causing myotonic dystrophy (DM) has recently been identified as an unstable CTG trinucleotide repeat located in the 3' untranslated region of a gene encoding for a protein with putative serine-threonine protein kinase activity. In this report we present the genomic sequences of the human and murine DM kinase gene. A comparison of these sequences with each other and with known cDNA sequences from both species, led us to predict a translation initiation codon, as well as determine the organization of the DM kinase gene. Several polymorphisms within the human DM kinase gene have been identified, and PCR assays to detect two of these are described. The complete sequence and characterization of the structure of the DM kinase gene, as well as the identification of novel polymorphisms within the gene, represent an important step in a further understanding of the genetics of myotonic dystrophy and the molecular biology of the gene.

Characterization of the myotonic dystrophy region predicts multiple protein isoform-encoding mRNAs.

The mutation underlying myotonic dystrophy (DM) has been identified as an expansion of a polymorphic CTG-repeat in a gene encoding protein kinase activity. Brain and heart transcripts of the DM-kinase (DMR-B15) gene are subject to alternative RNA splicing in both human and mouse. The unstable [CTG]5-30 motif is found uniquely in humans, although the flanking nucleotides are also present in mouse. Characterization of the DM region of both species reveals another active gene (DMR-N9) in close proximity to the kinase gene. DMR-N9 transcripts, mainly expressed in brain and testis, possess a single, large open reading frame, but the function of its protein product is unknown. Clinical manifestation of DM may be caused by the expanded CTG-repeat compromising the (alternative) expression of DM-kinase or DMR-N9 proteins.