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The generation of various phosphoinositide messenger molecules at distinct locations within the cell is mediated via the specific targeting of different isoforms and splice variants of phosphoinositide kinases. The lipid messenger PtdIns(4,5)P2 is generated by several of these enzymes when targeted to distinct cellular compartments. Several splice variants of the type Iγ isoform of PIPK (PtdIns4P 5-kinase), which generate PtdIns(4,5)P2, have been identified, and each splice variant is thought to serve a unique functional role within cells. Here, we have identified two novel C-terminal splice variants of PIPKIγ in human cells consisting of 700 and 707 amino acids. These two splice variants are expressed in multiple tissue types and display PIPK activity in vitro. Interestingly, both of these novel splice variants display distinct subcellular targeting. With the addition of these two new splice isoforms, there are minimally five PIPKIγ splice variants that have been identified in mammals. Therefore, we propose the use of the HUGO (Human Genome Organization) nomenclature in the naming of the splice isoforms. PIPKIγ_i4 (700 amino acids) is present in the nucleus, a targeting pattern that has not been previously observed in any PIPKIγ splice variant. PIPKIγ_i5 (707 amino acids) is targeted to intracellular vesicle-like structures, where it co-localizes with markers of several types of endosomal compartments. As occurs with other PIPKIγ splice variants, the distinctive C-terminal sequences of PIPKIγ_i4 and PIPKIγ_i5 may facilitate association with unique protein targeting factors, thereby localizing the kinases to their appropriate cellular subdomains for the site-specific generation of PtdIns(4,5)P2. [ABSTRACT FROM AUTHOR]

The morphogenesis of epithelial cells in the tissue microenvironment depends on the regulation of the forces and structures that keep cells in contact with their neighbours. The formation of cell–cell contacts is integral to the establishment and maintenance of epithelial morphogenesis. In epithelial tissues, the misregulation of the signalling pathways that control epithelial polarization induces migratory and invasive cellular phenotypes. Many cellular processes influence cadherin targeting and function, including exocytosis, endocytosis and recycling. However, the localized generation of the lipid messenger PtdIns(4,5)P2is emerging as a fundamental signal controlling all of these processes. The PtdIns(4,5)P2-generating enzymes, PIPKs (phosphatidylinositol phosphate kinases) are therefore integral to these pathways. By the spatial and temporal targeting of PIPKs via the actions of its functional protein associates, PtdIns(4,5)P2is generated at discrete cellular locales to provide the cadherin-trafficking machinery with its required lipid messenger. In the present review, we discuss the involvement of PtdIns(4,5)P2and the PIPKs in the regulation of the E-cadherin (epithelial cadherin) exocytic and endocytic machinery, the modulation of actin structures at sites of adhesion, and the direction of cellular pathways which determine the fate of E-cadherin and cell–cell junctions. Recent work is also described that has defined phosphoinositide-mediated E-cadherin regulatory pathways by the use of organismal models. [ABSTRACT FROM AUTHOR]

Insulin resistance leads to the inability of insulin to control the utilization and storage of glucose. It is associated initially with elevated levels of circulating insulin followed by glucose intolerance which may progress to type 2 diabetes, hyperlipidaemia, hypertension, obesity and cardiovascular diseases. While the causes of these diseases are multifactorial, one nutrient that is associated with all of these abnormalities is Cr. In the presence of Cr, in a biologically active form, much lower levels of insulin are required. Modern diets, which are often high in refined carbohydrates, are not only low in Cr, but lead to enhanced Cr losses. In response to the consumption of refined carbohydrates, there is a rapid rise in blood sugar leading to elevations in insulin that cause a mobilization of Cr. Once mobilized, Cr is not reabsorbed but lost via the urine leading to decreased Cr stores. Several studies involving both human subjects and experimental animals have reported improvements in insulin sensitivity, blood glucose, insulin, lipids, haemoglobin A1c, lean body mass and related variables in response to improved Cr nutrition. However, not all studies have reported beneficial effects associated with improved Cr nutrition. Well-controlled human studies are needed to document an unequivocal effect of Cr on insulin sensitivity in human subjects. Studies need to involve a significant number of subjects with insulin resistance, glucose intolerance or early stages of diabetes, who have not been taking supplements containing Cr for at least 4 months, and involve at least 400 to 600 μg supplemental Cr daily or more. Studies should be at least 4 months to document sustained effects of supplemental Cr on insulin resistance and related variables. Cr is a nutrient and not a therapeutic agent and therefore will only be of benefit to those whose problems are due to suboptimal intake of Cr.Chromium: Insulin resistance: Type 2 diabetes mellitus: Glucose metabolism: Supplementation [ABSTRACT FROM AUTHOR]

In mice that express lacZ under the control of a human dopamine β-hydroxylase gene promoter (DβH-nlacZ mice), the nuclei of enteric neurons express the transgene, as shown by the presence of β-galactosidase (β-gal) staining (Mercer et al. [1991] Neuron 7:703–716). The transgene is also expressed by neural crest-derived cells in the developing gut before their differentiation into neurons or glial cells (Kapur et al. [1992] Development 116:167–175). However, the cell types expressing the DβH-nlacZ transgene within the developing and adult gut have not been fully characterized. Whole-mount preparations of embryonic and adult gut were processed for histochemistry or immunohistochemistry to reveal β-gal plus markers of undifferentiated neural crest cells (in embryos) or enteric neurons (in adults). In embryonic mice, over 90% of undifferentiated neural crest-derived cells (identified using antibodies to p75) were β-gal+. Importantly, crest-derived cells at the migratory wavefront were all β-gal+. In adult mice, only a subpopulation of enteric neurons was β-gal+, while glial cells showed no β-gal staining. Considerable variation was observed between the small intestine and colon in the proportion of myenteric neurons that showed β-gal staining. We examined whether known classes of enteric neurons varied in their expression of DβH-nlacZ. In the myenteric plexus of the jejunum and colon, large calretinin+ neurons did not express lacZ, suggesting that the incomplete penetrance of the DβH-nlacZ transgene observed in adult mice is not random. We conclude that the DβH-nlacZ transgene provides a reliable marker for examining the colonization of the developing gut by neural crest cells. However, in adult mice, there is variation between mice, between gut regions, and between different classes of enteric neurons in the expression of the transgene. J. Comp. Neurol. 464:208–219, 2003. © 2003 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

State-of-the-art photometric measurements of extragalactic Cepheids account for the mean additional light due to chance superposition of Cepheids on crowded backgrounds through the use of artificial star measurements. However, light from stars physically associated with Cepheids may bias relative distance measurements if the changing spatial resolution along the distance ladder significantly alters the amount of associated blending. We have identified two regimes where this phenomenon may occur: Cepheids in wide binaries and in open clusters. We estimate stellar association bias using the photometric passbands and reddening-free Wesenheit magnitudes used to set up the distance scale. For wide binaries, we rely on Geneva stellar evolution models in conjunction with detailed statistics on intermediate-mass binary stars. For the impact of cluster stars, we have compiled information on the clustered Cepheid fraction and measured the typical cluster contribution in M31 via deep Hubble Space Telescope imaging provided by the Panchromatic Hubble Andromeda Treasury project. We find that the dominant effect on the distance scale comes from Cepheids in clusters, even though cluster Cepheids are a relatively rare phenomenon. Wide binaries have a negligible effect of 0.004% on H0 for long-period Cepheids observed in the near-infrared or when considering Wesenheit magnitudes. We estimate that blending due to cluster populations has previously resulted in a 0.23% overestimate of H0. Correcting for this bias, we obtain , which remains in 3.3σ tension with the Planck value. We conclude that stellar association bias does not constitute a limit for measuring H0 with an accuracy of 1%. [ABSTRACT FROM AUTHOR]

BACKGROUND Many children treated for cancer are at risk of infertility, but for girls and prepubertal boys, all fertility preservation techniques remain experimental. We have assessed UK practice relating to information provision about the effects of cancer treatment on fertility and options for fertility preservation. METHODS Paediatric oncologists prospectively completed a data form for each new patient registered over a 12 month period. RESULTS Data were available on 1030 patients (68% of total registered). The effect of cancer treatment on fertility was discussed with 63% of patients. Of these, 61% were judged to be at high or medium risk of fertility problems. Discussions took place more commonly with boys than girls; the commonest reason for discussion not occurring was young age. The majority (83%) of post-pubertal boys assessed as high/medium risk of infertility were referred for semen cryopreservation. This rate fell to 39% of those in early puberty. Only 1% (n=4) of girls were referred to an assisted conception unit. CONCLUSIONS These data indicate a high awareness of the potential adverse effects of therapy on fertility among UK paediatric oncologists. High referral rates for older boys indicate that current guidelines are followed, but there is a need for fertility preservation techniques for girls and younger boys. [ABSTRACT FROM AUTHOR]

Tissue-derived stem cells may offer future liver disease therapies. The developing human liver provides an excellent model to examine normal hepatic progenitor cell maturation, but candidate populations are poorly characterized. We sought to identify putative progenitor phenotypes in first-trimester human liver, by characterizing the architectural relationship between developing epithelial, mesenchymal, and hematopoietic lineages. Bipotential hepatoblasts were identified by co-expression of hepatocytic (cytokeratin 18, albumin) and biliary(cytokeratin 19) specific markers and epithelial-specific E-cadherin. Restriction of dlkpref-1 expression to hepatoblasts identifies this as a novel human marker allowing for hepatoblast sorting for in vitro analysis. Furthermore, the liver stem cell and haematopoietic marker Thy-1 was co-expressed with markers of hematopoietic (CD34) and mesenchymal (vimentin) lineage restriction on portal vein endothelium. Therefore, this structure may constitute a novel progenitor compartment with hemangioblast-like properties. [ABSTRACT FROM AUTHOR]

We present Hubble Space Telescope (HST) photometry of a selected sample of 50 long-period, low-extinction Milky Way Cepheids measured on the same WFC3 F555W-, F814W-, and F160W-band photometric system as extragalactic Cepheids in Type Ia supernova host galaxies. These bright Cepheids were observed with the WFC3 spatial scanning mode in the optical and near-infrared to mitigate saturation and reduce pixel-to-pixel calibration errors to reach a mean photometric error of 5 mmag per observation. We use the new Gaia DR2 parallaxes and HST photometry to simultaneously constrain the cosmic distance scale and to measure the DR2 parallax zeropoint offset appropriate for Cepheids. We find the latter to be −46 ± 13 μas or ±6 μas for a fixed distance scale, higher than found from quasars, as expected for these brighter and redder sources. The precision of the distance scale from DR2 has been reduced by a factor of 2.5 because of the need to independently determine the parallax offset. The best-fit distance scale is 1.006 ± 0.033, relative to the scale from Riess et al. with H0 = 73.24 km s−1 Mpc−1 used to predict the parallaxes photometrically, and is inconsistent with the scale needed to match the Planck 2016 cosmic microwave background data combined with ΛCDM at the 2.9σ confidence level (99.6%). At 96.5% confidence we find that the formal DR2 errors may be underestimated as indicated. We identify additional errors associated with the use of augmented Cepheid samples utilizing ground-based photometry and discuss their likely origins. Including the DR2 parallaxes with all prior distance-ladder data raises the current tension between the late and early universe route to the Hubble constant to 3.8σ (99.99%). With the final expected precision from Gaia, the sample of 50 Cepheids with HST photometry will limit to 0.5% the contribution of the first rung of the distance ladder to the uncertainty in H0. [ABSTRACT FROM AUTHOR]

We present year-long, near-infrared (NIR) Hubble Space Telescope (HST) WFC3 observations of Mira variables in the water megamaser host galaxy NGC 4258. Miras are asymptotic giant branch variables that can be divided into oxygen- (O-) and carbon- (C-) rich subclasses. Oxygen-rich Miras follow a tight (scatter ∼0.14 mag) period–luminosity relation (PLR) in the NIR and can be used to measure extragalactic distances. The water megamaser in NGC 4258 gives a geometric distance to the galaxy accurate to 2.6% that can serve to calibrate the Mira PLR. We develop criteria for detecting and classifying O-rich Miras with optical and NIR data as well as NIR data alone. In total, we discover 438 Mira candidates that we classify with high confidence as O-rich. Our most stringent criteria produce a sample of 139 Mira candidates that we use to measure a PLR. We use the OGLE-III sample of O-rich Miras in the Large Magellanic Cloud to obtain a relative distance modulus, μ4258 − μLMC = 10.95 ± 0.01 (statistical) ±0.06 (systematic) mag, that is statistically consistent with the relative distance determined using Cepheids. These results demonstrate the feasibility of discovering and characterizing Miras using the NIR with the HST and the upcoming James Webb Space Telescope and using those Miras to measure extragalactic distances and determine the Hubble constant. [ABSTRACT FROM AUTHOR]

We present the results of a study of the type II Cepheid (Ppuls = 4.974 days) in the eclipsing binary system OGLE-LMC-T2CEP-098 (Porb = 397.2 days). The Cepheid belongs to the peculiar W Vir group, for which the evolutionary status is virtually unknown. It is the first single-lined system with a pulsating component analyzed using the method developed by Pilecki et al. We show that the presence of a pulsator makes it possible to derive accurate physical parameters of the stars even if radial velocities can be measured for only one of the components. We have used four different methods to limit and estimate the physical parameters, eventually obtaining precise results by combining pulsation theory with the spectroscopic and photometric solutions. The Cepheid radius, mass, and temperature are , , and , respectively, while its companion has a similar size (), but is more massive () and hotter (9500 K). Our best estimate for the p-factor of the Cepheid is . The mass, position on the period–luminosity diagram, and pulsation amplitude indicate that the pulsating component is very similar to the Anomalous Cepheids, although it has a much longer period and is redder in color. The very unusual combination of the components suggest that the system has passed through a mass-transfer phase in its evolution. More complicated internal structure would then explain its peculiarity. [ABSTRACT FROM AUTHOR]

We present a high-precision measurement of the parallax for the 12-day Cepheid SS Canis Majoris, obtained via spatial scanning with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). Spatial scanning enables astrometric measurements with a precision of 20–40 μas, an order of magnitude better than pointed observations. SS CMa is the second Cepheid targeted for parallax measurement with HST and is the first of a sample of 18 long-period (≳10 days) Cepheids selected in order to improve the calibration of their period–luminosity relation and eventually permit a determination of the Hubble constant H0 to better than 2%. The parallax of SS CMa is found to be 348 ± 38 μas, corresponding to a distance of 2.9 ± 0.3 kpc. We also present a refinement of the static geometric distortion of WFC3 obtained using spatial scanning observations of calibration fields, with a typical magnitude ≲0.01 pixels on scales of 100 pixels. [ABSTRACT FROM AUTHOR]