Dimensions of central venous structures in humans measured in vivo using magnetic resonance imaging: implications for central-vein catheter dimensions.

The tip of a central vein catheter for hemodialysis should be located in the upper right atrium for the best performance. Hemodialysis catheters do have internal diameters unadjusted to the catheter length; however, the longer the catheter the slower the flow at the same pressure difference. On the other hand, the catheter diameter cannot be so large as to fill the vein too tightly as it predisposes to damage of the vein wall, thrombosis and stenosis.

Activation of MAPK cascades by GnRH: ERK and Jun N-terminal kinase are involved in basal and GnRH-stimulated activity of the glycoprotein hormone LHbeta-subunit promoter.

The role of ERK and Jun N-terminal kinase (JNK) in basal- and GnRH-stimulated LHbeta-promoter activity was examined in the gonadotroph cell line LbetaT-2. GnRH agonist (GnRH-A) stimulates the MAPK cascades ERK, JNK, and p38MAPK, with a peak at 7 min for ERK and at 60 min for JNK and p38MAPK. The rat glycoprotein hormone LHbeta-subunit promoter, linked to the chloramphenicol acetyl transferase (CAT) reporter gene, was used to follow its activation.

Cross-talk between Akt, p53 and Mdm2: possible implications for the regulation of apoptosis.

The p53 tumor suppressor protein and the Akt/PKB kinase play important roles in the transduction of pro-apoptotic and anti-apoptotic signals, respectively. We provide evidence that conflicting signals transduced by Akt and p53 are integrated via negative feedback between the two pathways. On the one hand, the combination of ionizing radiation and survival factor deprivation, which leads to rapid apoptosis of IL-3 dependent DA-1 cells, entails a caspase- and p53-dependent destruction of Akt.

ATM-dependent activation of the gene encoding MAP kinase phosphatase 5 by radiomimetic DNA damage.

Cellular responses to DNA damage are mediated by an extensive network of signaling pathways. The ATM protein kinase is a master regulator of the response to double-strand breaks (DSBs), the most cytotoxic DNA lesion caused by ionizing radiation. ATM is the protein missing or inactive in patients with the pleiotropic genetic disorder ataxia-telangiectasia (A-T).

Interactions of beta and gamma ENaC with Nedd4 can be facilitated by an ERK-mediated phosphorylation.

Phosphorylation of the epithelial Na(+) channel (ENaC) has been suggested to play a role in its regulation. Here we demonstrate that phosphorylating the carboxyl termini of the beta and gamma subunits facilitates their interactions with the ubiquitin ligase Nedd4 and inhibits channel activity. Three protein kinases, which phosphorylate the carboxyl termini of beta and gammaENaC, have been identified by an in vitro assay.

Non-regulated and stimulated mechanisms cooperate in the nuclear accumulation of MEK1.

MEKs, which operate within the ERK cascade, shuttle into the nucleus, but are rapidly exported from this location, forming an apparent cytosolic distribution both before and after stimulation. Two different mechanisms have been proposed for the nuclear translocation of MEKs. One of them involves a constant and non-regulated shuttling of MEKs into the nucleus operating both before and after mitogenic stimulation.

Intracellular signaling pathways mediated by the gonadotropin-releasing hormone (GnRH) receptor.

The hypothalamic gonadotropin-releasing hormone (GnRH) is a key regulator of the reproductive system, triggering the synthesis and release of LH and FSH in the pituitary. GnRH transmits its signal via two specific serpentine receptors that belong to the large group of G-protein coupled receptors (GPCRs). Here we review the intracellular signaling pathways mediated by the GnRH receptor (GnRHR).

Human Toll-like receptor 2 mediates induction of the antimicrobial peptide human beta-defensin 2 in response to bacterial lipoprotein.

Recognition of pathogens by Drosophila Toll or human Toll-like receptors results in translocation of Dorsal or its human homologue NF-kappaB, respectively; in Drosophila, this is followed by the production of antimicrobial peptides serving as antimicrobial effector system of the innate immune response. We investigated whether human Toll-like receptors also mediate induction of the synthesis of antimicrobial peptides. We found that HEK293 cells transfected with Toll-like receptor 2, but not wild-type cells responded to stimulation with bacterial lipoprotein by production of human beta-defensin 2.

Diagnostic and therapeutic impact of whole body positron emission tomography using fluorine-18-fluoro-2-deoxy-D-glucose in children with chronic granulomatous disease.

Aims: To compare whole body positron emission tomography (PET) using fluorine-18-fluoro-2-deoxy-D-glucose (FDG) with computed tomography (CT) in detecting active infective foci in children with chronic granulomatous disease.

Methods: We performed 22 whole body FDG PET studies in seven children with X linked (n = 6) or autosomal recessive (n = 1) CGD. All had clinical signs of infection and/or were evaluated prior to bone marrow transplantation (BMT).

Altered regulation of ERK1b by MEK1 and PTP-SL and modified Elk1 phosphorylation by ERK1b are caused by abrogation of the regulatory C-terminal sequence of ERKs.

ERK1b is an alternatively spliced form of ERK1, containing a 26-amino acid insertion between residues 340 and 341 of ERK1. Although under most circumstances the kinetics of ERK1b activation are similar to that of ERK1 and ERK2, we have previously found several conditions under which the activation of ERK1b by extracellular stimuli differs from that of other ERKs. We studied the molecular mechanisms that cause this differential regulation of ERK1b and found that ERK1b is altered in its ability to interact with MEK1 and this influenced its subcellular localization but not its kinetics of activation.

Mechanism of GnRH receptor signaling on gonadotropin release and gene expression in pituitary gonadotrophs.

Gonadotropin releasing hormone (GnRH), the first key hormone of reproduction, is synthesized and secreted from the hypothalamus in a pulsatile manner and stimulates pituitary gonadotrophs (5-10% of the pituitary cells) to synthesize and release gonadotropin luteinizing hormone (LH) and follicle stimulating hormone (FSH). Gonadotrophs consist of 60% multihormonal cells (LH+FSH) and 18% LH- and 22% FSH-containing cells. LH and FSH, members of the glycoprotein hormone family, stimulate spermatogenesis, folliculogenesis, and ovulation.

In vitro phosphorylation of COOH termini of the epithelial Na(+) channel and its effects on channel activity in Xenopus oocytes.

Recent findings have suggested the involvement of protein phosphorylation in the regulation of the epithelial Na(+) channel (ENaC). This study reports the in vitro phosphorylation of the COOH termini of ENaC subunits expressed as glutathione S-transferase fusion proteins. Channel subunits were specifically phosphorylated by kinase-enriched cytosolic fractions derived from rat colon.

Involvement of the activation loop of ERK in the detachment from cytosolic anchoring.

The Extracellular signal-regulated kinases (ERKs) are translocated into the nucleus in response to mitogenic stimulation. The mechanism of translocation and the residues in ERKs that govern this process are not clear as yet. Here we studied the involvement of residues in the activation loop of ERK2 in determining its subcellular localization.

Taxol-induced apoptosis depends on MAP kinase pathways (ERK and p38) and is independent of p53.

The anti-cancer agent paclitaxel (Taxol) stabilizes microtubules leading to G2/M cell cycle arrest and apoptotic cell death. In order to analyse the molecular mechanisms of Taxol-induced cytotoxicity, we studied the involvement of mitogen-activated protein kinases (MAPK) ERK and p38 as well as the p53 pathways in Taxol-induced apoptosis. The human breast carcinoma cell line MCF7 and its derivatives, MCF7/HER-2 and MDD2, were used in the study.

Involvement of the ERK mitogen-activated protein kinase in cell resistance to complement-mediated lysis.

Sublytic doses of complement desensitize cells and make them resistant to lytic complement doses. This process, named complement-induced protection, requires calcium ion influx, protein kinase C activation and protein synthesis. The involvement of the extracellular signal-regulated kinase, ERK, in cell desensitization by sublytic complement was examined in erythroleukaemia K562 cells and in COS-7 cells.

The ERK signaling cascade inhibits gonadotropin-stimulated steroidogenesis.

The response of granulosa cells to luteinizing hormone (LH) and follicle-stimulating hormone (FSH) is mediated mainly by cAMP/protein kinase A (PKA) signaling. Notably, the activity of the extracellular signal-regulated kinase (ERK) signaling cascade is elevated in response to these stimuli as well. We studied the involvement of the ERK cascade in LH- and FSH-induced steroidogenesis in two granulosa-derived cell lines, rLHR-4 and rFSHR-17, respectively.

The CK2 phosphorylation of vitronectin. Promotion of cell adhesion via the alpha(v)beta 3-phosphatidylinositol 3-kinase pathway.

Phosphorylation of vitronectin (Vn) by casein kinase II was previously shown to occur at Thr50 and Thr57 and to augment a major physiological function of vitronectin-cell adhesion and spreading. Here we show that this phosphorylation increases cell adhesion via the alpha(v)beta3 (not via the alpha(v)beta5 integrin), suggesting that alpha(v)beta3 differs from alpha(v)beta5 in its biorecognition profile. Although both the phospho (CK2-PVn) and non-phospho (Vn) analogs of vitronectin (simulated by mutants Vn(T50E,T57E), and Vn(T50A,T57A), respectively) trigger the alpha(v)beta3 as well as the alpha(v)beta5 integrins, and equally activate the ERK pathway, these two forms are different in their activation of the focal adhesion kinase/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB) pathway.

Lipid constituents in oligodendroglial cells alter susceptibility to H2O2-induced apoptotic cell death via ERK activation.

The present work examines the effect of membrane lipid composition on activation of extracellular signal-regulated protein kinases (ERK) and cell death following oxidative stress. When subjected to 50 microM docosahexaenoic acid (DHA, 22 : 6 n-3), cellular phospholipids of OLN 93 cells, a clonal line of oligodendroglia origin low in DHA, were enriched with this polyunsaturated fatty acid. In the presence of 1 mM N,N-dimethylethanolamine (dEa) a new phospholipid species analog was formed in lieu of phosphatidylcholine.

V(D)J recombination defects in lymphocytes due to RAG mutations: severe immunodeficiency with a spectrum of clinical presentations.

Severe combined immunodeficiency (SCID) comprises a heterogeneous group of primary immunodeficiencies, a proportion of which are due to mutations in either of the 2 recombination activating genes (RAG)-1 and -2, which mediate the process of V(D)J recombination leading to the assembly of antigen receptor genes. It is reported here that the clinical and immunologic phenotypes of patients bearing mutations in RAGs are more diverse than previously thought and that this variability is related, in part, to the specific type of RAG mutation. By analyzing 44 such patients from 41 families, the following conclusions were reached: (1) null mutations on both alleles lead to the T-B-SCID phenotype; (2) patients manifesting classic Omenn syndrome (OS) have missense mutations on at least one allele and maintain partial V(D)J recombination activity, which accounts for the generation of residual, oligoclonal T-lymphocytes; (3) in a third group of patients, findings were only partially compatible with OS, and these patients, who also carried at least one missense mutation, may be considered to have atypical SCID/OS; (4) patients with engraftment of maternal T cells as a complication of a transplacental transfusion represented a fourth group, and these patients, who often presented with a clinical phenotype mimicking OS, may be observed regardless of the type of RAG gene mutation.

Expression of MHC class II molecules contributes to lipopolysaccharide responsiveness.

Activation of phagocytes by lipopolysaccharide (LPS) causes synthesis and secretion of various mediators of inflammation. CD14, a glycosylphosphatidylinositol-anchored monocytic antigen serving as receptor for LPS, and members of the family of Toll-like receptors mediate cellular activation in response to LPS. Here we investigated whether expression of MHC class II molecules modified the response to LPS.

Role of dynamin, Src, and Ras in the protein kinase C-mediated activation of ERK by gonadotropin-releasing hormone.

G-protein-coupled receptors are a large group of integral membranal receptors, which in response to ligand binding initiate diverse downstream signaling. Here we studied the gonadotropin-releasing hormone (GnRH) receptor, which uses Gq for its downstream signaling. We show that extracellular signal-regulated kinase (ERK) activation is fully dependent on protein kinase C (PKC), but only partially dependent on Src, dynamin, and Ras.

Lentivirus-mediated gene transfer of gp91phox corrects chronic granulomatous disease (CGD) phenotype in human X-CGD cells.

Background: Chronic granulomatous diseases (CGD) are caused by impaired antimicrobial activity in phagocytes, due to the absence or malfunction of the respiratory burst NADPH oxidase. Two-thirds of the patients have mutations in their X-linked CGD gene encoding gp91phox, the largest subunit of the NADPH oxidase.

Methods: Aimed at gene therapy of X-CGD already at the level of resting pluripotent hematopoietic stem cells, we generated an advanced HIV-1-based vector with self-inactivating (SIN2) features containing the therapeutic gp91phox gene.

Bone marrow transplantation with unrelated donors: what is the probability of identifying an HLA-A/B/Cw/DRB1/B3/B5/DQB1-matched donor?

Patients transplanted with marrow from an HLA-ABDR serologically matched unrelated donor suffer from more post-transplant complications than those who are transplanted with marrow from an HLA-identical sibling. This is most likely due to either HLA-ABDR incompatibilities not resolved by standard techniques and/or HLA polymorphisms not tested for by routine tissue typing (HLA-Cw,-DQ). By resolving these incompatibilities by molecular techniques combined with the in vitro cytotoxic T lymphocyte precursor frequency (CTLpf) test, we have shown that a high degree of HLA compatibility is associated with increased patient survival.