Importance of Radioactive Labelling to Elucidate Inositol Polyphosphate Signalling

Inositol polyphosphates, in their water-soluble or lipid-bound forms, represent a large and multifaceted family of signalling molecules. Some inositol polyphosphates are well recognised as defining important signal transduction pathways, as in the case of the calcium release factor Ins(1,4,5)P3, generated by receptor activation-induced hydrolysis of the lipid PtdIns(4,5)P2 by phospholipase C. The birth of inositol polyphosphate research would not have occurred without the use of radioactive phosphate tracers that enabled the discovery of the “PI response”. Radioactive labels, mainly of phosphorus but also carbon and hydrogen (tritium), have been instrumental in the development of this research field and the establishment of the inositol polyphosphates as one of the most important networks of regulatory molecules present in eukaryotic cells. Advancements in microscopy and mass spectrometry and the development of colorimetric assays have facilitated inositol polyphosphate research, but have not eliminated the need for radioactive experimental approaches. In fact, such experiments have become easier with the cloning of the inositol polyphosphate kinases, enabling the systematic labelling of specific positions of the inositol ring with radioactive phosphate. This approach has been valuable for elucidating their metabolic pathways and identifying specific and novel functions for inositol polyphosphates. For example, the synthesis of radiolabelled inositol pyrophosphates has allowed the discovery of a new protein post-translational modification. Therefore, radioactive tracers have played and will continue to play an important role in dissecting the many complex aspects of inositol polyphosphate physiology. In this review we aim to highlight the historical importance of radioactivity in inositol polyphosphate research, as well as its modern usage

ITPK1 mediates the lipid-independent synthesis of inositol phosphates controlled by metabolism

Inositol phosphates (IPs) comprise a network of phosphorylated molecules that play multiple signaling roles in eukaryotes. IPs synthesis is believed to originate with IP_{3} generated from PIP_{2} by phospholipase C (PLC). Here, we report that in mammalian cells PLC-generated IPs are rapidly recycled to inositol, and uncover the enzymology behind an alternative “soluble” route to synthesis of IPs. Inositol tetrakisphosphate 1-kinase 1 (ITPK1)—found in Asgard archaea, social amoeba, plants, and animals—phosphorylates I(3)P_{1} originating from glucose-6-phosphate, and I(1)P_{1} generated from sphingolipids, to enable synthesis of IP_{6}. We also found using PAGE mass assay that metabolic blockage by phosphate starvation surprisingly increased IP_{6} levels in a ITPK1-dependent manner, establishing a route to IP_{6} controlled by cellular metabolic status, that is not detectable by traditional [{3}^H]-inositol labeling. The presence of ITPK1 in archaeal clades thought to define eukaryogenesis indicates that IPs had functional roles before the appearance of the eukaryote

Special Topic Issue: The Role of the Environment in Infection Prevention

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Factors in patients’ experience of hospital care: Evidence from California, 2009–2011

The use of measures of patient-centered care to evaluate hospital care is mandated by The Patient Protection and Affordable Care Act of 2010. Using three years of data from 315 California acute-care hospitals and data collected from patients via the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey, we seek to evaluate patients’ hospital-care experience by (1) analyzing patients’ experience-of-care scores in light of these hospitals’ patient profiles, structural characteristics, and outcomes in 2011, and (2) determining and analyzing the extent of changes in patients’ experience of care over the three-year period 2009–2011. For 2011, we find significant variation in patients’ experience-of-care scores associated with hospitals’ different patient profiles and structural characteristics. In spite of these single-year differences, virtually all aspects of patients’ experience of care showed improvement over the 2009-2011 period

A systematic review of internet-based selfmanagement interventions for youth with health conditions.

Objective Critically appraise research evidence on effectiveness of internet self-management interventions on health outcomes in youth with health conditions. Methods Published studies of internet interventions in youth with health conditions were evaluated. Electronic searches were conducted in EBM Reviews-Cochrane Central Register of Controlled Trials, Medline, EMBASE, CINAHL and PsychINFO. Two reviewers independently selected articles for review and assessed methodological quality. Of 29 published articles on internet interventions; only nine met the inclusion criteria and were included in analysis. Results While outcomes varied greatly between studies, symptoms improved in internet interventions compared to control conditions in seven of nine studies. There was conflicting evidence regarding disease-specific knowledge and quality of life, and evidence was limited regarding decreases in health care utilization. Conclusions There are the beginnings of an evidence base that self-management interventions delivered via the internet improve selected outcomes in certain childhood illnesses

MINPP1 prevents intracellular accumulation of the chelator inositol hexakisphosphate and is mutated in Pontocerebellar Hypoplasia

Inositol polyphosphates are vital metabolic and secondary messengers, involved in diverse cellular functions. Therefore, tight regulation of inositol polyphosphate metabolism is essential for proper cell physiology. Here, we describe an early-onset neurodegenerative syndrome caused by loss-of-function mutations in the multiple inositol-polyphosphate phosphatase 1 gene (MINPP1). Patients are found to have a distinct type of Pontocerebellar Hypoplasia with typical basal ganglia involvement on neuroimaging. We find that patient-derived and genome edited MINPP1−/− induced stem cells exhibit an inefficient neuronal differentiation combined with an increased cell death. MINPP1 deficiency results in an intracellular imbalance of the inositol polyphosphate metabolism. This metabolic defect is characterized by an accumulation of highly phosphorylated inositols, mostly inositol hexakisphosphate (IP6), detected in HEK293 cells, fibroblasts, iPSCs and differentiating neurons lacking MINPP1. In mutant cells, higher IP6 level is expected to be associated with an increased chelation of intracellular cations, such as iron or calcium, resulting in decreased levels of available ions. These data suggest the involvement of IP6-mediated chelation on Pontocerebellar Hypoplasia disease pathology and thereby highlight the critical role of MINPP1 in the regulation of human brain development and homeostasis

In Vitro Surfactant Structure-Toxicity Relationships: Implications for Surfactant Use in Sexually Transmitted Infection Prophylaxis and Contraception

Background The need for woman-controlled, cheap, safe, effective, easy-to-use and easy-to-store topical applications for prophylaxis against sexually transmitted infections (STIs) makes surfactant-containing formulations an interesting option that requires a more fundamental knowledge concerning surfactant toxicology and structure-activity relationships. Methodology/Principal Findings We report in vitro effects of surfactant concentration, exposure time and structure on the viability of mammalian cell types typically encountered in the vagina, namely, fully polarized and confluent epithelial cells, confluent but non-polarized epithelial-like cells, dendritic cells, and human sperm. Representatives of the different families of commercially available surfactants – nonionic (Triton X-100 and monolaurin), zwitterionic (DDPS), anionic (SDS), and cationic (CnTAB (n = 10 to 16), C12PB, and C12BZK) – were examined. Triton X-100, monolaurin, DDPS and SDS were toxic to all cell types at concentrations around their critical micelle concentration (CMC) suggesting a non-selective mode of action involving cell membrane destabilization and/or destruction. All cationic surfactants were toxic at concentrations far below their CMC and showed significant differences in their toxicity toward polarized as compared with non-polarized cells. Their toxicity was also dependent on the chemical nature of the polar head group. Our results suggest an intracellular locus of action for cationic surfactants and show that their structure-activity relationships could be profitably exploited for STI prophylaxis in vaginal gel formulations. The therapeutic indices comparing polarized epithelial cell toxicity to sperm toxicity for all surfactants examined, except C12PB and C12BZK, does not justify their use as contraceptive agents. C12PB and C12BZK are shown to have a narrow therapeutic index recommending caution in their use in contraceptive formulations. Conclusions/Significance Our results contribute to understanding the mechanisms involved in surfactant toxicity, have a predictive value with regard to their safety, and may be used to design more effective and less harmful surfactants for use in topical applications for STI prophylaxis.Foundation for Science and Technology of the Portuguese Ministry of Science and Higher Educatio

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

Una mirada estudiantil calificadora al profesorado de la Universidad Técnica de Machala

Este estudio se realizó en la carrera de Educación Básica de la Universidad Técnica de Machala con el propósito de identificar los criterios de los estudiantes en relación a la labor docente desplegada por sus profesores y socializar estas creencias. La estrategia metodológica asumida responde al paradigma cuanti-cualitativo, se basa en los métodos: fenomenológico, revisión bibliográfica, analítico-sintético y estadístico; la información se obtuvo a través de las técnicas de entrevista en profundidad y el cuestionario, aplicadas a los 138 matriculados en esta carrera que permitieron concluir que en general los profesores se caracterizan por la organización de sus clases, la paciencia mostrada durante la explicación del contenido, la claridad de sus explicaciones y respuestas a las interrogantes de los educandos, la atención a las dificultades del estudiante, la utilidad de las tareas didácticas que asigna y el dominio de los contenidos. No obstante, existen limitaciones en cuanto a las relaciones con los dicentes, el dominio de las tecnologías, y el conocimiento y la puesta en práctica de metodologías de enseñanza que permitan lograr mayor calidad en la formación de los futuros egresados, lo que se refleja en el criterio de estos, quienes manifiestan la posibilidad de recomendarlos a otros condiscípulo