The role of tight junctions in paracellular ion transport in the renal tubule: lessons learned from a rare inherited tubular disorder.

Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is an autosomal recessive renal tubular disorder that typically presents with disturbances in magnesium and calcium homeostasis, recurrent urinary tract infections, and polyuria and/or polydipsia. Patients with FHHNC have high risk of the development of chronic kidney disease and end-stage renal disease in early adolescence. Multiple distinct mutations in the CLDN16 gene, which encodes a tight junction protein, have been found responsible for this disorder.

Highly specific antibodies for co-detection of human choline kinase α1 and α2 isoforms.

Background: Choline kinase is the first enzyme in the CDP-choline pathway that synthesizes phosphatidylcholine, the major phospholipid in eukaryotic cell membranes. In humans, choline kinase exists as three isoforms (CKα1, α2, and β). Specific inhibition of CKα has been reported to selectively kill tumoral cells.

Immunosuppression and renal outcome in congenital and pediatric steroid-resistant nephrotic syndrome.

Background And Objectives: Mutations in podocyte genes are associated with steroid-resistant nephrotic syndrome (SRNS), mostly affecting younger age groups. To date, it is unclear whether these patients benefit from intensified immunosuppression with cyclosporine A (CsA). The aim of this study was to evaluate the influence of podocyte gene defects in congenital nephrotic syndrome (CNS) and pediatric SRNS on the efficacy of CsA therapy and preservation of renal function.

The sugar ring of the nucleoside is required for productive substrate positioning in the active site of human deoxycytidine kinase (dCK): implications for the development of dCK-activated acyclic guanine analogues.

The low toxicity of acyclovir (ACV) is mainly due to the fact that human nucleoside kinases have undetectable phosphorylation rates with this acyclic guanine analogue. In contrast, herpes virus thymidine kinase (HSV1-TK) readily activates ACV. We wanted to understand why human deoxycytidine kinase (dCK), which is related to HSV1-TK and phosphorylates deoxyguanosine, does not accept acyclic guanine analogues as substrates.

Structural and kinetic characterization of human deoxycytidine kinase variants able to phosphorylate 5-substituted deoxycytidine and thymidine analogues .

The physiological role of human deoxycytidine kinase (dCK) is to phosphorylate deoxynucleosides required for DNA synthesis, with the exception of thymidine. Previous structural analysis of dCK implicated steric factors, specifically the thymine methyl group at the 5-position, that prevent thymidine phosphorylation by dCK. This hypothesis is supported by the observation that mutations that enlarge the active site cavity in proximity to the nucleoside 5-position endow dCK with the ability to phosphorylate thymidine.

Health-related quality of life, psychosocial strains, and coping in parents of children with chronic renal failure.

Health-related quality of life (HRQOL) in parents of children suffering from renal disease is often diminished by the illness burden experienced in daily life and by unfavorable ways of coping. Our aim was to examine the relationship between psychosocial strains perceived by parents, their ways of coping, and HRQOL. In an anonymous cross-sectional study, parents completed a questionnaire concerning psychosocial strains, coping strategies, and HRQOL, as well as sociodemographic and illness parameters.

First outbreak of Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae in Germany.

We report the first outbreak of Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae in Germany. The presence of KPC was confirmed by polymerase chain reaction (PCR).

Functional and physical interactions between formyl-peptide-receptors and scavenger receptor MARCO and their involvement in amyloid beta 1-42-induced signal transduction in glial cells.

Recent studies suggest that the chemotactic G protein-coupled receptor formyl-peptide-receptor-like-1 (FPRL1) or the scavenger receptor MARCO (macrophage receptor with collagenous structure) plays an essential role in the inflammatory response of host defense mechanisms and neurodegenerative disorders such as Alzheimer's disease. We therefore analyzed the involvement of FPRL1 and MARCO in amyloid beta1-42 (Abeta1-42)-induced signalling by extracellular-signal regulated kinases 1/2 (ERK1/2) phosphorylation and cAMP level measurement in glial cells (astrocytes and microglia) and in transfected HEK293 cells. Receptors were inhibited by small interference RNA and the consequences in Abeta1-42- and MARCO agonist fucoidan-induced signal transduction were determined.

Rapid identification of multidrug-resistant Mycobacterium tuberculosis isolates by rpoB gene scanning using high-resolution melting curve PCR analysis.

Background: Multidrug-resistant (MDR) Mycobacterium tuberculosis poses a serious threat to the control of tuberculosis (TB) and constitutes an increasing public health problem. The availability of rapid in vitro susceptibility tests is a prerequisite for optimal patient treatment. Rifampicin resistance caused by diverse mutations in the rpoB gene is an established and widely used surrogate marker for MDR-TB.

Extending thymidine kinase activity to the catalytic repertoire of human deoxycytidine kinase.

Salvage of nucleosides in the cytosol of human cells is carried out by deoxycytidine kinase (dCK) and thymidine kinase 1 (TK1). Whereas TK1 is only responsible for thymidine phosphorylation, dCK is capable of converting dC, dA, and dG into their monophosphate forms. Using structural data on dCK, we predicted that select mutations at the active site would, in addition to making the enzyme faster, expand the catalytic repertoire of dCK to include thymidine.

Evidence for a parity doublet Delta(1920)P33 and Delta(1940)D33 from gammap-->ppi;{0}eta.

Evidence is reported for the existence of a parity doublet of Delta resonances with total angular momentum J=3/2 from photoproduction of the ppi;{0}eta final state. The two parity partners Delta(1920)P33 and Delta(1940)D33 make significant contributions to the reaction. Cascades of resonances into Delta(1232)eta, N(1535)pi, and Na0(980) are clearly observed.

Familial hypomagnesaemia with hypercalciuria and nephrocalcinosis (FHHNC): compound heterozygous mutation in the claudin 16 (CLDN16) gene.

Background: Familial hypomagnesaemia with hypercalciuria and nephrocalcinosis (FHHNC) is an autosomal recessive disorder of renal calcium and magnesium wasting frequently complicated by progressive chronic renal failure in childhood or adolescence.

Methods: A 7 year old boy was investigated following the findings of marked renal insufficiency and nephrocalcinosis in his 18-month old sister. He too was found to have extensive nephrocalcinosis with increased fractional excretion of magnesium: 12.

Structural requirements for calmodulin binding to membrane-associated guanylate kinase homologs.

Effector molecules such as calmodulin modulate the interactions of membrane-associated guanylate kinase homologs (MAGUKs) and other scaffolding proteins of the membrane cytoskeleton by binding to the Src homology 3 (SH3) domain, the guanylate kinase (GK) domain, or the connecting HOOK region of MAGUKs. Using surface plasmon resonance, we studied the interaction of members of all four MAGUK subfamilies--synapse-associated protein 97 (SAP97), calcium/calmodulin-dependent serine protein kinase (CASK), membrane palmitoylated protein 2 (MPP2), and zona occludens (ZO) 1--and calmodulin to determine interaction affinities and localize the binding site. The SH3-GK domains of the proteins and derivatives thereof were expressed in E.

Involvement of formyl-peptide-receptor-like-1 and phospholipase D in the internalization and signal transduction of amyloid beta 1-42 in glial cells.

Recent studies suggest that the formyl-peptide-receptor-like-1 (FPRL1) plays an essential role in the inflammatory responses of host defense mechanisms and neurodegenerative disorders such as Alzheimer's disease (AD). We therefore analyzed whether amyloid beta1-42 (Abeta1-42) increased the activity of phospholipase D (PLD) via FPRL1, which is an enzyme involved in the secretion, endocytosis and receptor signaling. PLD activity was determined using a transphosphatidylation assay.

Elucidation of different binding modes of purine nucleosides to human deoxycytidine kinase.

Purine nucleoside analogues of medicinal importance, such as cladribine, require phosphorylation by deoxycytidine kinase (dCK) for pharmacological activity. Structural studies of ternary complexes of human dCK show that the enzyme conformation adjusts to the different hydrogen-bonding properties between dA and dG and to the presence of substituent at the 2-position present in dG and cladribine. Specifically, the carbonyl group in dG elicits a previously unseen conformational adjustment of the active site residues Arg104 and Asp133.

Restoration of the antiviral activity of 3'-azido-3'-deoxythymidine (AZT) against AZT-resistant human immunodeficiency virus by delivery of engineered thymidylate kinase to T cells.

Emergence of antiviral drug resistance is a major challenge to human immunodeficiency virus (HIV) therapy. The archetypal example of this problem is loss of antiviral activity of the nucleoside analogue 3'-azido-3'-deoxythymidine (AZT), caused by mutations in reverse transcriptase (RT), the viral polymerase. AZT resistance results from an imbalance between rates of AZT-induced proviral DNA chain termination and RT-induced excision of the chain-terminating nucleotide.

Long-term follow-up of a patient with primary hypomagnesaemia and secondary hypocalcaemia due to a novel TRPM6 mutation.

Hypomagnesaemia with secondary hypocalcaemia (HSH) is a rare condition usually presenting in the newborn period as refractory seizures, other symptoms of increased neuromuscular excitability and growth disturbances. A case with a novel TRPM6 mutation with an excellent long-term outcome is reported to highlight the observation that clinical suspicion is essential for an early diagnosis and treatment of HSH. The compliance of a long-term treatment with oral magnesium supplements is critical to avoid abnormalities of neurological and physical development.

Modification of the omega-meson lifetime in nuclear matter.

Information on hadron properties in the nuclear medium has been derived from the photoproduction of omega mesons on the nuclei C, Ca, Nb, and Pb using the Crystal Barrel/TAPS detector at the ELSA tagged photon facility in Bonn. The dependence of the omega-meson cross section on the nuclear mass number has been compared with three different types of models: a Glauber analysis, a Boltzmann-Uehling-Uhlenbeck analysis of the Giessen theory group, and a calculation by the Valencia theory group. In all three cases, the inelastic omega width is found to be 130-150 MeV/c(2) at normal nuclear matter density for an average 3-momentum of 1.

Evaluating PVALB as a candidate gene for SLC12A3-negative cases of Gitelman's syndrome.

Background: Loss-of-function mutations in SLC12A3 coding for the thiazide-sensitive NaCl cotransporter (NCC) cause Gitelman's syndrome (GS), a recessively inherited salt-losing tubulopathy. Most GS patients are compound heterozygous. However, up to 30% of GS patients carry only a single mutant allele, and a normal SLC12A3 screening is also observed in a small subset of patients.