Roles of Pofut1 and O-fucose in mammalian Notch signaling.

Mammalian Notch receptors contain 29-36 epidermal growth factor (EGF)-like repeats that may be modified by protein O-fucosyltransferase 1 (Pofut1), an essential component of the canonical Notch signaling pathway. The Drosophila orthologue Ofut1 is proposed to function as both a chaperone required for stable cell surface expression of Notch and a protein O-fucosyltransferase. Here we investigate these dual roles of Pofut1 in relation to endogenous Notch receptors of Chinese hamster ovary and murine embryonic stem (ES) cells.

Mouse fertility is enhanced by oocyte-specific loss of core 1-derived O-glycans.

Regulation of the number of eggs ovulated by different mammalian species remains poorly understood. Here we show that oocyte-specific deletion at the primary follicle stage of core 1 beta1,3-galactosyltransferase (T-synthase; generates core 1-derived O-glycans), leads to a sustained increase in fertility. T-syn mutant females ovulated 30-50% more eggs and had a sustained increase in litter size compared to controls.

Risk factors associated with acute hip prosthetic joint infections and outcome of treatment with a rifampinbased regimen.

Background And Purpose: Acute prosthetic infection is a serious problem. We report factors related to the incidence of acute infection and results of combined joint debridement and prolonged rifampicin-based antibiotic therapy.

Patients And Methods: Between 1998 and 2004, 14 acute infections occurred after 819 primary hip arthroplasties.

The O-fucose glycan in the ligand-binding domain of Notch1 regulates embryogenesis and T cell development.

Mechanisms by which the extracellular domain of Notch1 controls Notch1 signaling are not well defined. Here, we show that the O-fucose glycan in the Notch1 ligand-binding domain regulates the strength of Notch1 signaling during embryogenesis, postweaning growth, and T cell development in the mouse. Heterozygotes carrying a Notch1(12f) allele and an inactive Notch1 allele die at approximately embryonic day (E)12 with a typical Notch1 null phenotype.

Preventing or accelerating emergency care for children with complex healthcare needs.

Objective: A subgroup of children with special health care needs (CSHCN) have chronic and complex medical conditions and frequently attend the emergency department (ED). Some of these ED visits could be prevented through appropriate clinician advice or, if an ED visit is unavoidable, the management time could be decreased. We set out to determine whether an ED-based advice and coordination programme was feasible and could prevent or accelerate ED care for these patients.

Intermediate-affinity LFA-1 binds alpha-actinin-1 to control migration at the leading edge of the T cell.

T lymphocytes use LFA-1 to migrate into lymph nodes and inflammatory sites. To investigate the mechanisms regulating this migration, we utilize mAbs selective for conformational epitopes as probes for active LFA-1. Expression of the KIM127 epitope, but not the 24 epitope, defines the extended conformation of LFA-1, which has intermediate affinity for ligand ICAM-1.

Regulation of Notch signaling by glycosylation.

Notch receptors are approximately 300 kDa cell surface glycoproteins whose activation by Notch ligands regulates cell fate decisions in the metazoa. The extracellular domain of Notch receptors has many epidermal growth factor like repeats that are glycosylated with O-fucose and O-glucose glycans as well as N-glycans. Disruption of O-fucose glycan synthesis leads to severe Notch signaling defects in Drosophila and mammals.

The regulatory function of plasma-membrane Ca(2+)-ATPase (PMCA) in the heart.

The PMCA (plasma-membrane Ca(2+)-ATPase) is a ubiquitously expressed calcium-extruding enzymatic pump important in the control of intracellular calcium concentration. Unlike in non-excitable cells, where PMCA is the only system for calcium extrusion, in excitable cells, such as cardiomyocytes, PMCA has been shown to play only a minor role in calcium homoeostasis compared with the NCX (sodium/calcium exchanger), another system of calcium extrusion. However, increasing evidence points to an important role for PMCA in signal transduction; of particular interest in cardiac physiology is the modulation of nNOS (neuronal nitric oxide synthase) by isoform 4b of PMCA.

Flexor tendon retrieval-another way.

A simple method of flexor tendon retrieval after division in Zones I and II injuries using a silastic urinary catheter is described.

Characterization of interactions of adapter protein RAPL/Nore1B with RAP GTPases and their role in T cell migration.

Using a model of integrin-triggered random migration of T cells, we show that stimulation of LFA-1 integrins leads to the activation of Rap1 and Rap2 small GTPases. We further show that Rap1 and Rap2 have distinct roles in adhesion and random migration of these cells and that an adapter protein from the Ras association domain family (Rassf), RAPL, has a role downstream of Rap2 in addition to its link to Rap1. Further characterization of the RAPL protein and its interactions with small GTPases from the Ras family shows that RAPL forms more stable complexes with Rap2 and classical Ras proteins compared with Rap1.

The role of the integrin LFA-1 in T-lymphocyte migration.

A successful immune response depends on the migration of lymphocytes into lymph nodes or inflamed tissues where they make contact with antigen-presenting cells. We are interested in how one member of the integrin family, leukocyte function-associated antigen-1 (LFA-1), controls the function and, in particular, the migration of immune cells. We find that this integrin operates not only as an adhesion receptor for T lymphoblasts (T cells) but also induces their migration in vitro at approximately 15 microm/min.

New liver cell mutants defective in the endocytic pathway.

To isolate mutant liver cells defective in the endocytic pathway, a selection strategy using toxic ligands for two distinct membrane receptors was utilized. Rare survivors termed trafficking mutants (Trf2-Trf7) were stable and more resistant than the parental HuH-7 cells to both toxin conjugates. They differed from the previously isolated Trf1 HuH-7 mutant as they expressed casein kinase 2 alpha'' (CK2alpha'') which is missing from Trf1 cells and which corrects the Trf1 trafficking phenotype.

The threonine that carries fucose, but not fucose, is required for Cripto to facilitate Nodal signaling.

Cripto is a membrane-bound co-receptor for Nodal, a member of the transforming growth factor-beta superfamily. Mouse embryos lacking either Cripto or Nodal have the same lethal phenotype at embryonic day 7.5.

A method to the madness of N-glycan complexity?

Cell-surface glycoprotein receptors have varying numbers of N-glycan sites. In this issue of Cell, Lau et al. (2007) report that increasing intracellular UDP-GlcNAc leads to increased branching of N-glycans, increased receptor association with cell-surface galectin-3, and enhanced signaling.

Erysipelas-like inflammation following breast surgery.

Impaired lymph drainage is an inevitable consequence of any form of surgery that disrupts lymphatics, resulting in a degree of lymphoedema that may vary from subtle to dramatic and although classically involving an entire limb, may be more localised, confined to only a small area such as a skin flap. Infection is a well-recognised complication of lymphoedema. However, not all inflammatory episodes occurring in the setting of lymphatic dysfunction can be clearly attributed to infection as this article demonstrates.

Fertilization in mouse does not require terminal galactose or N-acetylglucosamine on the zona pellucida glycans.

Fertilization in mammals requires sperm to bind to the zona pellucida (ZP) that surrounds the egg. Galactose (Gal) or N-acetylglucosamine (GlcNAc) residues on the glycans of ZP protein 3 (ZP3) have been implicated as mouse sperm receptors. However, Mgat1(-/-) eggs with modified N-glycans lacking terminal Gal and GlcNAc residues are fertilized.

Treatment of staphylococcal prosthetic joint infections with debridement, prosthesis retention and oral rifampicin and fusidic acid.

There is growing evidence of the efficacy of treating early staphylococcal infections of prosthetic joints with surgical debridement and prosthesis retention, combined with oral antibiotic regimens that include rifampicin in combination with a fluoroquinolone. With rising rates of fluoroquinolone-resistant staphylococci, evidence concerning the efficacy of alternative combinations of antibiotics is required. Twenty patients with staphylococcal prosthetic joint infections who had been treated with surgical debridement and prosthesis retention, and a combination of rifampicin and fusidic acid were analysed.

Comparison of the clock test and a questionnaire-based test for screening for cognitive impairment in Nigerians.

Background: Since it is projected that by 2020 seventy percent of the elderly will reside in developing countries, a reliable screening method for dementia and cognitive impairment in general in populations with diverse languages, culture, education and literacy will be needed. We sought to determine if the Clock Test, a screening test for dementia, was suitable for use in a Nigerian population.

Study Design: Cross-sectional survey of 54 men and 12 women from Northern Nigeria.

Roles of O-fucose glycans in notch signaling revealed by mutant mice.

Notch receptor signaling is important for many developmental processes in the metazoa. Insights into how Notch receptor signaling is regulated have been obtained from the characterization of mutants of model organisms in which Notch signaling is perturbed. Here we describe the effects of mutations that alter the glycosylation of Notch receptors and Notch ligands in the mouse.

Lectin-resistant CHO glycosylation mutants.

Chinese hamster ovary (CHO) mutant cells with a wide variety of alterations in the glycosylation of proteins and lipids have been isolated by selection for resistance to the cytotoxicity of plant lectins. These CHO mutants have been used to characterize glycosylation pathways, to identify genes that code for glycosylation activities, to elucidate functional roles of glycans that mediate biological processes, and for glycosylation engineering. In this chapter, we briefly describe the available panel of lectin-resistant CHO mutants and summarize their glycan alterations and the biochemical and genetic bases of mutation.