Publications by authors named "Jessica Houston"

40 Publications

CYTO Virtual.

Cytometry A 2021 Feb 31;99(2):127-128. Epub 2021 Jan 31.

Newcastle University Flow Cytometry Core Facility and Innovation, Methodology and Application Research Theme, UK.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cyto.a.24303DOI Listing
February 2021

Investigating differences between tamoxifen resistant and sensitive breast cancer cells with flow cytometry.

Cytometry A 2021 Feb 28;99(2):164-169. Epub 2021 Jan 28.

Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico, USA.

The active metabolite of tamoxifen, 4-hydroxytamoxifen, functions as an anti-estrogen in breast cancer cells and thus inhibits proliferation. While tamoxifen continues to be successfully used to treat estrogen-dependent breast cancer, most patients receiving treatment will develop chemoresistance over time. Two commonly reported biomarkers of tamoxifen resistance are decreased expression of insulin-like growth factor 1 receptor (IGF-1R) and increased expression of epidermal growth factor receptor (EGFR). In prior work we have shown that these receptors facilitate chemoresistance and have unique regulatory functions measurable in resistant cell lines compared with nonresistant. Thus, we hypothesized that these receptors and a newly identified biomarker, integrin β1, may be used to search for the presence of resistant breast cancer cells within a population of cells that are sensitive to tamoxifen therapy. We tested this by designing a straightforward cell-labeling approach to measure differences in the receptor expression of resistant vs. sensitive cells cytometrically. Our results show that separation is possible when observing the expression of IGF-1R as well as integrin β1. Interestingly, we found no detectable difference in EGFR expression between tamoxifen resistant and -sensitive cells when measured with cytometry despite the fact that EGFR is upregulated in resistant cells. Our long-term goal is to utilize sorting to isolate tamoxifen resistant subpopulations of cells by receptor expression level. Isolating rare resistant cells that reside within a population of drug-sensitive cells will offer new insights into why chemoresistance occurs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cyto.a.24306DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7986838PMC
February 2021

Evaluation of Caspase-3 Activity During Apoptosis with Fluorescence Lifetime-Based Cytometry Measurements and Phasor Analyses.

Cytometry A 2020 12 25;97(12):1265-1275. Epub 2020 Aug 25.

Department of Chemical & Materials Engineering, New Mexico State University, Las Cruces, New Mexico, USA.

Caspase-3 is a well-described protease with many roles that impact the fate of a cell. During apoptosis, caspase-3 acts as an executioner caspase with important proteolytic functions that lead to the final stages of programmed cell death. Owing to this key role, caspase-3 is exploited intracellularly as a target of control of apoptosis for therapeutic outcomes. Yet the activation of caspase-3 during apoptosis is challenged by other roles and functions (e.g., paracrine signaling). This brief report presents a way to track caspase-3 levels using a flow cytometer that measures excited state fluorescence lifetimes and a signal processing approach that leads to a graphical phasor-based interpretation. An established Förster resonance energy transfer (FRET) bioprobe was used for this test; the connected donor and acceptor fluorophore is cleavable by caspase-3 during apoptosis induction. With the cell-by-cell decay kinetic data and phasor analyses we generate a caspase activation trajectory, which is used to interpret activation throughout apoptosis. When lifetime-based cytometry is combined with a FRET bioprobe and phasor analyses, enzyme activation can be simplified and quantified with phase and modulation data. We envision extrapolating this approach to high content screening, and reinforce the power of phasor approaches with cytometric data. Analyses such as these can be used to cluster cells by their phase and modulation "lifetime fingerprint" when the intracellular fluorescent probe is utilized as a sensor of enzyme activity. © 2020 The Authors. Cytometry Part A published by Wiley Periodicals LLC on behalf of International Society for Advancement of Cytometry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cyto.a.24207DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7738394PMC
December 2020

Guidelines for the use of flow cytometry and cell sorting in immunological studies (second edition).

Authors:
Andrea Cossarizza Hyun-Dong Chang Andreas Radbruch Andreas Acs Dieter Adam Sabine Adam-Klages William W Agace Nima Aghaeepour Mübeccel Akdis Matthieu Allez Larissa Nogueira Almeida Giorgia Alvisi Graham Anderson Immanuel Andrä Francesco Annunziato Achille Anselmo Petra Bacher Cosima T Baldari Sudipto Bari Vincenzo Barnaba Joana Barros-Martins Luca Battistini Wolfgang Bauer Sabine Baumgart Nicole Baumgarth Dirk Baumjohann Bianka Baying Mary Bebawy Burkhard Becher Wolfgang Beisker Vladimir Benes Rudi Beyaert Alfonso Blanco Dominic A Boardman Christian Bogdan Jessica G Borger Giovanna Borsellino Philip E Boulais Jolene A Bradford Dirk Brenner Ryan R Brinkman Anna E S Brooks Dirk H Busch Martin Büscher Timothy P Bushnell Federica Calzetti Garth Cameron Ilenia Cammarata Xuetao Cao Susanna L Cardell Stefano Casola Marco A Cassatella Andrea Cavani Antonio Celada Lucienne Chatenoud Pratip K Chattopadhyay Sue Chow Eleni Christakou Luka Čičin-Šain Mario Clerici Federico S Colombo Laura Cook Anne Cooke Andrea M Cooper Alexandra J Corbett Antonio Cosma Lorenzo Cosmi Pierre G Coulie Ana Cumano Ljiljana Cvetkovic Van Duc Dang Chantip Dang-Heine Martin S Davey Derek Davies Sara De Biasi Genny Del Zotto Gelo Victoriano Dela Cruz Michael Delacher Silvia Della Bella Paolo Dellabona Günnur Deniz Mark Dessing James P Di Santo Andreas Diefenbach Francesco Dieli Andreas Dolf Thomas Dörner Regine J Dress Diana Dudziak Michael Dustin Charles-Antoine Dutertre Friederike Ebner Sidonia B G Eckle Matthias Edinger Pascale Eede Götz R A Ehrhardt Marcus Eich Pablo Engel Britta Engelhardt Anna Erdei Charlotte Esser Bart Everts Maximilien Evrard Christine S Falk Todd A Fehniger Mar Felipo-Benavent Helen Ferry Markus Feuerer Andrew Filby Kata Filkor Simon Fillatreau Marie Follo Irmgard Förster John Foster Gemma A Foulds Britta Frehse Paul S Frenette Stefan Frischbutter Wolfgang Fritzsche David W Galbraith Anastasia Gangaev Natalio Garbi Brice Gaudilliere Ricardo T Gazzinelli Jens Geginat Wilhelm Gerner Nicholas A Gherardin Kamran Ghoreschi Lara Gibellini Florent Ginhoux Keisuke Goda Dale I Godfrey Christoph Goettlinger Jose M González-Navajas Carl S Goodyear Andrea Gori Jane L Grogan Daryl Grummitt Andreas Grützkau Claudia Haftmann Jonas Hahn Hamida Hammad Günter Hämmerling Leo Hansmann Goran Hansson Christopher M Harpur Susanne Hartmann Andrea Hauser Anja E Hauser David L Haviland David Hedley Daniela C Hernández Guadalupe Herrera Martin Herrmann Christoph Hess Thomas Höfer Petra Hoffmann Kristin Hogquist Tristan Holland Thomas Höllt Rikard Holmdahl Pleun Hombrink Jessica P Houston Bimba F Hoyer Bo Huang Fang-Ping Huang Johanna E Huber Jochen Huehn Michael Hundemer Christopher A Hunter William Y K Hwang Anna Iannone Florian Ingelfinger Sabine M Ivison Hans-Martin Jäck Peter K Jani Beatriz Jávega Stipan Jonjic Toralf Kaiser Tomas Kalina Thomas Kamradt Stefan H E Kaufmann Baerbel Keller Steven L C Ketelaars Ahad Khalilnezhad Srijit Khan Jan Kisielow Paul Klenerman Jasmin Knopf Hui-Fern Koay Katja Kobow Jay K Kolls Wan Ting Kong Manfred Kopf Thomas Korn Katharina Kriegsmann Hendy Kristyanto Thomas Kroneis Andreas Krueger Jenny Kühne Christian Kukat Désirée Kunkel Heike Kunze-Schumacher Tomohiro Kurosaki Christian Kurts Pia Kvistborg Immanuel Kwok Jonathan Landry Olivier Lantz Paola Lanuti Francesca LaRosa Agnès Lehuen Salomé LeibundGut-Landmann Michael D Leipold Leslie Y T Leung Megan K Levings Andreia C Lino Francesco Liotta Virginia Litwin Yanling Liu Hans-Gustaf Ljunggren Michael Lohoff Giovanna Lombardi Lilly Lopez Miguel López-Botet Amy E Lovett-Racke Erik Lubberts Herve Luche Burkhard Ludewig Enrico Lugli Sebastian Lunemann Holden T Maecker Laura Maggi Orla Maguire Florian Mair Kerstin H Mair Alberto Mantovani Rudolf A Manz Aaron J Marshall Alicia Martínez-Romero Glòria Martrus Ivana Marventano Wlodzimierz Maslinski Giuseppe Matarese Anna Vittoria Mattioli Christian Maueröder Alessio Mazzoni James McCluskey Mairi McGrath Helen M McGuire Iain B McInnes Henrik E Mei Fritz Melchers Susanne Melzer Dirk Mielenz Stephen D Miller Kingston H G Mills Hans Minderman Jenny Mjösberg Jonni Moore Barry Moran Lorenzo Moretta Tim R Mosmann Susann Müller Gabriele Multhoff Luis Enrique Muñoz Christian Münz Toshinori Nakayama Milena Nasi Katrin Neumann Lai Guan Ng Antonia Niedobitek Sussan Nourshargh Gabriel Núñez José-Enrique O'Connor Aaron Ochel Anna Oja Diana Ordonez Alberto Orfao Eva Orlowski-Oliver Wenjun Ouyang Annette Oxenius Raghavendra Palankar Isabel Panse Kovit Pattanapanyasat Malte Paulsen Dinko Pavlinic Livius Penter Pärt Peterson Christian Peth Jordi Petriz Federica Piancone Winfried F Pickl Silvia Piconese Marcello Pinti A Graham Pockley Malgorzata Justyna Podolska Zhiyong Poon Katharina Pracht Immo Prinz Carlo E M Pucillo Sally A Quataert Linda Quatrini Kylie M Quinn Helena Radbruch Tim R D J Radstake Susann Rahmig Hans-Peter Rahn Bartek Rajwa Gevitha Ravichandran Yotam Raz Jonathan A Rebhahn Diether Recktenwald Dorothea Reimer Caetano Reis e Sousa Ester B M Remmerswaal Lisa Richter Laura G Rico Andy Riddell Aja M Rieger J Paul Robinson Chiara Romagnani Anna Rubartelli Jürgen Ruland Armin Saalmüller Yvan Saeys Takashi Saito Shimon Sakaguchi Francisco Sala-de-Oyanguren Yvonne Samstag Sharon Sanderson Inga Sandrock Angela Santoni Ramon Bellmàs Sanz Marina Saresella Catherine Sautes-Fridman Birgit Sawitzki Linda Schadt Alexander Scheffold Hans U Scherer Matthias Schiemann Frank A Schildberg Esther Schimisky Andreas Schlitzer Josephine Schlosser Stephan Schmid Steffen Schmitt Kilian Schober Daniel Schraivogel Wolfgang Schuh Thomas Schüler Reiner Schulte Axel Ronald Schulz Sebastian R Schulz Cristiano Scottá Daniel Scott-Algara David P Sester T Vincent Shankey Bruno Silva-Santos Anna Katharina Simon Katarzyna M Sitnik Silvano Sozzani Daniel E Speiser Josef Spidlen Anders Stahlberg Alan M Stall Natalie Stanley Regina Stark Christina Stehle Tobit Steinmetz Hannes Stockinger Yousuke Takahama Kiyoshi Takeda Leonard Tan Attila Tárnok Gisa Tiegs Gergely Toldi Julia Tornack Elisabetta Traggiai Mohamed Trebak Timothy I M Tree Joe Trotter John Trowsdale Maria Tsoumakidou Henning Ulrich Sophia Urbanczyk Willem van de Veen Maries van den Broek Edwin van der Pol Sofie Van Gassen Gert Van Isterdael René A W van Lier Marc Veldhoen Salvador Vento-Asturias Paulo Vieira David Voehringer Hans-Dieter Volk Anouk von Borstel Konrad von Volkmann Ari Waisman Rachael V Walker Paul K Wallace Sa A Wang Xin M Wang Michael D Ward Kirsten A Ward-Hartstonge Klaus Warnatz Gary Warnes Sarah Warth Claudia Waskow James V Watson Carsten Watzl Leonie Wegener Thomas Weisenburger Annika Wiedemann Jürgen Wienands Anneke Wilharm Robert John Wilkinson Gerald Willimsky James B Wing Rieke Winkelmann Thomas H Winkler Oliver F Wirz Alicia Wong Peter Wurst Jennie H M Yang Juhao Yang Maria Yazdanbakhsh Liping Yu Alice Yue Hanlin Zhang Yi Zhao Susanne Maria Ziegler Christina Zielinski Jakob Zimmermann Arturo Zychlinsky

Eur J Immunol 2019 Oct;49(10):1457-1973

Max Planck Institute for Infection Biology, Berlin, Germany.

These guidelines are a consensus work of a considerable number of members of the immunology and flow cytometry community. They provide the theory and key practical aspects of flow cytometry enabling immunologists to avoid the common errors that often undermine immunological data. Notably, there are comprehensive sections of all major immune cell types with helpful Tables detailing phenotypes in murine and human cells. The latest flow cytometry techniques and applications are also described, featuring examples of the data that can be generated and, importantly, how the data can be analysed. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid, all written and peer-reviewed by leading experts in the field, making this an essential research companion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/eji.201970107DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7350392PMC
October 2019

Apoptosis and autophagy.

Cytometry A 2019 06;95(6):655-656

Chemical and Materials Engineering, New Mexico State University, Las Cruces, New Mexico.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cyto.a.23837DOI Listing
June 2019

Resilience in Children Exposed to Violence: A Meta-analysis of Protective Factors Across Ecological Contexts.

Clin Child Fam Psychol Rev 2019 09;22(3):406-431

Department of Psychology, Marquette University, 604 North 16th Street, Milwaukee, WI, 53233, USA.

Children who experience violence in their families and communities are at increased risk for a wide range of psychological and behavioral difficulties, but some exhibit resilience, or adaptive functioning following adversity. Understanding what promotes resilience is critical for developing more effective prevention and intervention strategies. Over 100 studies have examined potential protective factors for children exposed to violence in the past 30 years, but there has been no quantitative review of this literature. In order to identify which protective factors have received the strongest empirical support, we conducted a meta-analysis of 118 studies involving 101,592 participants. We separately evaluated cross-sectional (n = 71) and longitudinal (n = 47) studies testing bivariate, additive, and buffering effects for eleven proposed protective factors. Effect sizes generally were stronger in cross-sectional than longitudinal studies, but four protective factors-self-regulation, family support, school support, and peer support-demonstrated significant additive and/or buffering effects in longitudinal studies. Results were consistent across type of violence experienced (i.e., maltreatment, intimate partner violence, community violence). The review highlights the most robust predictors of resilience, identifies limitations of this work, and offers directions for improving our understanding of the processes and programs that foster resilience in children exposed to violence.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10567-019-00293-1DOI Listing
September 2019

Cytometry Score: 23 to 4.

Cytometry A 2019 03 21;95(3):259-260. Epub 2019 Jan 21.

Executive Strategic Advisory, IVD and Biotech, Boston, Massachusetts.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cyto.a.23713DOI Listing
March 2019

Fluorescence lifetime shifts of NAD(P)H during apoptosis measured by time-resolved flow cytometry.

Cytometry A 2019 01 19;95(1):70-79. Epub 2018 Oct 19.

Chemical & Materials Engineering, New Mexico State University, Las Cruces, New Mexico.

Autofluorescence from the intracellular metabolite, NAD(P)H, is a biomarker that is widely used and known to reliably screen and report metabolic activity as well as metabolic fluctuations within cells. As a ubiquitous endogenous fluorophore, NAD(P)H has a unique rate of fluorescence decay that is altered when bound to coenzymes. In this work we measure the shift in the fluorescence decay, or average fluorescence lifetime (1-3 ns), of NAD(P)H and correlate this shift to changes in metabolism that cells undergo during apoptosis. Our measurements are made with a flow cytometer designed specifically for fluorescence lifetime acquisition within the ultraviolet to violet spectrum. Our methods involved culture, treatment, and preparation of cells for cytometry and microscopy measurements. The evaluation we performed included observations and quantification of the changes in endogenous emission owing to the induction of apoptosis as well as changes in the decay kinetics of the emission measured by flow cytometry. Shifts in NAD(P)H fluorescence lifetime were observed as early as 15 min post-treatment with an apoptosis inducing agent. Results also include a phasor analysis to evaluate free to bound ratios of NAD(P)H at different time points. We defined the free to bound ratios as the ratio of 'short-to-long' (S/L) fluorescence lifetime, where S/L was found to consistently decrease with an increase in apoptosis. With a quantitative framework such as phasor analysis, the short and long lifetime components of NAD(P)H can be used to map the cycling of free and bound NAD(P)H during the early-to-late stages of apoptosis. The combination of lifetime screening and phasor analyses provides the first step in high throughput metabolic profiling of single cells and can be leveraged for screening and sorting for a range of applications in biomedicine. © 2018 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cyto.a.23606DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6587805PMC
January 2019

Evaluating integrin activation with time-resolved flow cytometry.

J Biomed Opt 2018 07;23(7):1-10

New Mexico State University, Department of Chemical and Materials Engineering, Las Cruces, New Mexic, United States.

Förster resonance energy transfer (FRET) continues to be a useful tool to study movement and interaction between proteins within living cells. When FRET as an optical technique is measured with flow cytometry, conformational changes of proteins can be rapidly measured cell-by-cell for the benefit of screening and profiling. We exploit FRET to study the extent of activation of α4β1 integrin dimers expressed on the surface of leukocytes. The stalk-like transmembrane heterodimers when not active lay bent and upon activation extend outward. Integrin extension is determined by changes in the distance of closest approach between an FRET donor and acceptor, bound at the integrin head and cell membrane, respectively. Time-resolved flow cytometry analysis revealed donor emission increases up to 17%, fluorescence lifetime shifts over 1.0 ns during activation, and FRET efficiencies of 37% and 26% corresponding to the inactive and active integrin state, respectively. Last, a graphical phasor analysis, including population clustering, gating, and formation of an FRET trajectory, added precision to a comparative analysis of populations undergoing FRET, partial donor recovery, and complete donor recovery. This work establishes a quantitative cytometric approach for profiling fluorescence donor decay kinetics during integrin conformational changes on a single-cell level.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1117/1.JBO.23.7.075004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6232766PMC
July 2018

Young infants expect an unfamiliar adult to comfort a crying baby: Evidence from a standard violation-of-expectation task and a novel infant-triggered-video task.

Cogn Psychol 2018 05 6;102:1-20. Epub 2018 Jan 6.

Institute of Child Development, University of Minnesota, 51 East River Parkway, Minneapolis, MN 55455, United States. Electronic address:

Do infants expect individuals to act prosocially toward others in need, at least in some contexts? Very few such expectations have been uncovered to date. In three experiments, we examined whether infants would expect an adult alone in a scene with a crying baby to attempt to comfort the baby. In the first two experiments, 12- and 4-month-olds were tested using the standard violation-of-expectation method. Infants saw videotaped events in which a woman was performing a household chore when a baby nearby began to cry; the woman either comforted (comfort event) or ignored (ignore event) the baby. Infants looked significantly longer at the ignore than at the comfort event, and this effect was eliminated if the baby laughed instead of cried. In the third experiment, 8-month-olds were tested using a novel forced-choice violation-of-expectation method, the infant-triggered-video method. Infants faced two computer monitors and were first shown that touching the monitors triggered events: One monitor presented the comfort event and the other monitor presented the ignore event. Infants then chose which event they wanted to watch again by touching the corresponding monitor. Infants significantly chose the ignore over the comfort event, and this effect was eliminated if the baby laughed. Thus, across ages and methods, infants provided converging evidence that they expected the adult to comfort the crying baby. These results indicate that expectations about individuals' actions toward others in need are already present in the first year of life, and, as such, they constrain theoretical accounts of early prosociality and morality.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cogpsych.2017.12.004DOI Listing
May 2018

Overview of Fluorescence Lifetime Measurements in Flow Cytometry.

Methods Mol Biol 2018 ;1678:421-446

Kinetic River Corp., 897, Independence Avenue, Suite 4A, Mountain View, CA, 94043-2357, USA.

The focus of this chapter is time-resolved flow cytometry, which is broadly defined as the ability to measure the timing of fluorescence decay from excited fluorophores that pass through cytometers or high-throughput cell counting and cell sorting instruments. We focus on this subject for two main reasons: first, to discuss the nuances of hardware and software modifications needed for these measurements because currently, there are no widespread time-resolved cytometers nor a one-size-fits-all approach; and second, to summarize the application space for fluorescence lifetime-based cell counting/sorting owing to the recent increase in the number of investigators interested in this approach. Overall, this chapter is structured into three sections: (1) theory of fluorescence decay kinetics, (2) modern time-resolved flow cytometry systems, and (3) cell counting and sorting applications. These commentaries are followed by conclusions and discussion about new directions and opportunities for fluorescence lifetime measurements in flow cytometry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/978-1-4939-7346-0_18DOI Listing
June 2018

Guidelines for the use of flow cytometry and cell sorting in immunological studies.

Authors:
Andrea Cossarizza Hyun-Dong Chang Andreas Radbruch Mübeccel Akdis Immanuel Andrä Francesco Annunziato Petra Bacher Vincenzo Barnaba Luca Battistini Wolfgang M Bauer Sabine Baumgart Burkhard Becher Wolfgang Beisker Claudia Berek Alfonso Blanco Giovanna Borsellino Philip E Boulais Ryan R Brinkman Martin Büscher Dirk H Busch Timothy P Bushnell Xuetao Cao Andrea Cavani Pratip K Chattopadhyay Qingyu Cheng Sue Chow Mario Clerici Anne Cooke Antonio Cosma Lorenzo Cosmi Ana Cumano Van Duc Dang Derek Davies Sara De Biasi Genny Del Zotto Silvia Della Bella Paolo Dellabona Günnur Deniz Mark Dessing Andreas Diefenbach James Di Santo Francesco Dieli Andreas Dolf Vera S Donnenberg Thomas Dörner Götz R A Ehrhardt Elmar Endl Pablo Engel Britta Engelhardt Charlotte Esser Bart Everts Anita Dreher Christine S Falk Todd A Fehniger Andrew Filby Simon Fillatreau Marie Follo Irmgard Förster John Foster Gemma A Foulds Paul S Frenette David Galbraith Natalio Garbi Maria Dolores García-Godoy Jens Geginat Kamran Ghoreschi Lara Gibellini Christoph Goettlinger Carl S Goodyear Andrea Gori Jane Grogan Mor Gross Andreas Grützkau Daryl Grummitt Jonas Hahn Quirin Hammer Anja E Hauser David L Haviland David Hedley Guadalupe Herrera Martin Herrmann Falk Hiepe Tristan Holland Pleun Hombrink Jessica P Houston Bimba F Hoyer Bo Huang Christopher A Hunter Anna Iannone Hans-Martin Jäck Beatriz Jávega Stipan Jonjic Kerstin Juelke Steffen Jung Toralf Kaiser Tomas Kalina Baerbel Keller Srijit Khan Deborah Kienhöfer Thomas Kroneis Désirée Kunkel Christian Kurts Pia Kvistborg Joanne Lannigan Olivier Lantz Anis Larbi Salome LeibundGut-Landmann Michael D Leipold Megan K Levings Virginia Litwin Yanling Liu Michael Lohoff Giovanna Lombardi Lilly Lopez Amy Lovett-Racke Erik Lubberts Burkhard Ludewig Enrico Lugli Holden T Maecker Glòria Martrus Giuseppe Matarese Christian Maueröder Mairi McGrath Iain McInnes Henrik E Mei Fritz Melchers Susanne Melzer Dirk Mielenz Kingston Mills David Mirrer Jenny Mjösberg Jonni Moore Barry Moran Alessandro Moretta Lorenzo Moretta Tim R Mosmann Susann Müller Werner Müller Christian Münz Gabriele Multhoff Luis Enrique Munoz Kenneth M Murphy Toshinori Nakayama Milena Nasi Christine Neudörfl John Nolan Sussan Nourshargh José-Enrique O'Connor Wenjun Ouyang Annette Oxenius Raghav Palankar Isabel Panse Pärt Peterson Christian Peth Jordi Petriz Daisy Philips Winfried Pickl Silvia Piconese Marcello Pinti A Graham Pockley Malgorzata Justyna Podolska Carlo Pucillo Sally A Quataert Timothy R D J Radstake Bartek Rajwa Jonathan A Rebhahn Diether Recktenwald Ester B M Remmerswaal Katy Rezvani Laura G Rico J Paul Robinson Chiara Romagnani Anna Rubartelli Beate Ruckert Jürgen Ruland Shimon Sakaguchi Francisco Sala-de-Oyanguren Yvonne Samstag Sharon Sanderson Birgit Sawitzki Alexander Scheffold Matthias Schiemann Frank Schildberg Esther Schimisky Stephan A Schmid Steffen Schmitt Kilian Schober Thomas Schüler Axel Ronald Schulz Ton Schumacher Cristiano Scotta T Vincent Shankey Anat Shemer Anna-Katharina Simon Josef Spidlen Alan M Stall Regina Stark Christina Stehle Merle Stein Tobit Steinmetz Hannes Stockinger Yousuke Takahama Attila Tarnok ZhiGang Tian Gergely Toldi Julia Tornack Elisabetta Traggiai Joe Trotter Henning Ulrich Marlous van der Braber René A W van Lier Marc Veldhoen Salvador Vento-Asturias Paulo Vieira David Voehringer Hans-Dieter Volk Konrad von Volkmann Ari Waisman Rachael Walker Michael D Ward Klaus Warnatz Sarah Warth James V Watson Carsten Watzl Leonie Wegener Annika Wiedemann Jürgen Wienands Gerald Willimsky James Wing Peter Wurst Liping Yu Alice Yue Qianjun Zhang Yi Zhao Susanne Ziegler Jakob Zimmermann

Eur J Immunol 2017 10;47(10):1584-1797

Maurice Müller Laboratories (DKF), Universitätsklinik für Viszerale Chirurgie und Medizin Inselspital, University of Bern, Murtenstrasse, Bern.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/eji.201646632DOI Listing
October 2017

Imaging cytometry: Automated morphology and feature extraction.

Cytometry A 2017 09;91(9):851-853

Department of Chemicals and Materials Engineering, New Mexico State University, New Mexico.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cyto.a.23200DOI Listing
September 2017

Shifts in the fluorescence lifetime of EGFP during bacterial phagocytosis measured by phase-sensitive flow cytometry.

Sci Rep 2017 01 16;7:40341. Epub 2017 Jan 16.

Chemical and Materials Engineering, New Mexico State University, Las Cruces, NM, 88003, USA.

Phase-sensitive flow cytometry (PSFC) is a technique in which fluorescence excited state decay times are measured as fluorescently labeled cells rapidly transit a finely focused, frequency-modulated laser beam. With PSFC the fluorescence lifetime is taken as a cytometric parameter to differentiate intracellular events that are challenging to distinguish with standard flow cytometry. For example PSFC can report changes in protein conformation, expression, interactions, and movement, as well as differences in intracellular microenvironments. This contribution focuses on the latter case by taking PSFC measurements of macrophage cells when inoculated with enhanced green fluorescent protein (EGFP)-expressing E. coli. During progressive internalization of EGFP-E. coli, fluorescence lifetimes were acquired and compared to control groups. It was hypothesized that fluorescence lifetimes would correlate well with phagocytosis because phagosomes become acidified and the average fluorescence lifetime of EGFP is known to be affected by pH. We confirmed that average EGFP lifetimes consistently decreased (3 to 2 ns) with inoculation time. The broad significance of this work is the demonstration of how high-throughput fluorescence lifetime measurements correlate well to changes that are not easily tracked by intensity-only cytometry, which is affected by heterogeneous protein expression, cell-to-cell differences in phagosome formation, and number of bacterium engulfed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/srep40341DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5238435PMC
January 2017

Predicting aggression in late adolescent romantic relationships: A short-term longitudinal study.

J Adolesc 2016 Dec 3;53:237-248. Epub 2016 Nov 3.

Marquette University, United States.

This study sought to prospectively predict aggression in the romantic relationships of 1180 college students from the United States (807 females; 373 males) over the course of two months with a set of intrapersonal risk and protective factors, including personality characteristics that rarely have been examined in this population. After accounting for prior dating aggression, perpetration of verbal aggression was predicted uniquely by aggressive attitudes, emotion regulation, and for females, narcissism. Perpetration of physical aggression was predicted by aggressive attitudes, but only at low levels of emotion regulation, and the interaction of callous-unemotional traits, emotion regulation, and gender: males with low levels of callous-unemotional traits perpetrated less physical aggression when they reported greater emotion regulation. These findings are among the first to show that personality traits and emotion regulation prospectively predict partner aggression in late adolescence and suggest mechanisms for continuity in interpersonal aggression from early adolescence to adulthood.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.adolescence.2016.10.012DOI Listing
December 2016

Perspectives of an ISAC Marylou Ingram Scholar.

Cytometry A 2016 07;89(7):627-8

Saxonian Incubator for Clinical Translation (SIKT), University Leipzig, Leipzig, Germany.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cyto.a.22908DOI Listing
July 2016

Phasor plotting with frequency-domain flow cytometry.

Opt Express 2016 Jun;24(13):14596-607

Interest in time resolved flow cytometry is growing. In this paper, we collect time-resolved flow cytometry data and use it to create polar plots showing distributions that are a function of measured fluorescence decay rates from individual fluorescently-labeled cells and fluorescent microspheres. Phasor, or polar, graphics are commonly used in fluorescence lifetime imaging microscopy (FLIM). In FLIM measurements, the plotted points on a phasor graph represent the phase-shift and demodulation of the frequency-domain fluorescence signal collected by the imaging system for each image pixel. Here, we take a flow cytometry cell counting system, introduce into it frequency-domain optoelectronics, and process the data so that each point on a phasor plot represents the phase shift and demodulation of an individual cell or particle. In order to demonstrate the value of this technique, we show that phasor graphs can be used to discriminate among populations of (i) fluorescent microspheres, which are labeled with one fluorophore type; (ii) Chinese hamster ovary (CHO) cells labeled with one and two different fluorophore types; and (iii) Saccharomyces cerevisiae cells that express combinations of fluorescent proteins with different fluorescence lifetimes. The resulting phasor plots reveal differences in the fluorescence lifetimes within each sample and provide a distribution from which we can infer the number of cells expressing unique single or dual fluorescence lifetimes. These methods should facilitate analysis time resolved flow cytometry data to reveal complex fluorescence decay kinetics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5025209PMC
http://dx.doi.org/10.1364/OE.24.014596DOI Listing
June 2016

Evaluation of the catalytic activity and cytotoxicity of palladium nanocubes: the role of oxygen.

ACS Appl Mater Interfaces 2015 May 30;7(18):9364-71. Epub 2015 Apr 30.

†Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003, United States.

Recently, it has been reported that palladium nanocubes (PdNC) are capable of generating singlet oxygen without photoexcitation simply via chemisorption of molecular oxygen on its surface. Such a trait would make PdNC a highly versatile catalyst suitable in organic synthesis and a Reactive Oxygen Species (ROS) inducing cancer treatment reagent. Here we thoroughly investigated the catalytic activity of PdNC with respect to their ability to produce singlet oxygen and to oxidize 3,3',5,5'-tetramethylbenzidine (TMB), and analyzed the cytotoxic properties of PdNC on HeLa cells. Our findings showed no evidence of singlet oxygen production by PdNC. The nanocubes' activity is not necessarily linked to activation of oxygen. The oxidation of substrate on PdNC can be a first step, followed by PdNC regeneration with oxygen or other oxidant. The catalytic activity of PdNC toward the oxidation of TMB is very high and shows direct two-electron oxidation when the surface of the PdNC is clean and the ratio of TMB/PdNC is not very high. Sequential one electron oxidation is observed when the pristine quality of PdNC surface is compromised by serum or uncontrolled impurities and/or the ratio of TMB/PdNC is high. Clean PdNC in serum-free media efficiently induce apoptosis of HeLa cells. It is the primary route of cell death and is associated with hyperpolarization of mitochondria, contrary to a common mitochondrial depolarization initiated by ROS. Again, the effects are very sensitive to how well the pristine surface of PdNC is preserved, suggesting that PdNC can be used as an apoptosis inducing agent, but only with appropriate drug delivery system.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/am509124xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4663053PMC
May 2015

Toward the measurement of multiple fluorescence lifetimes in flow cytometry: maximizing multi-harmonic content from cells and microspheres.

J Biophotonics 2015 Nov 26;8(11-12):908-17. Epub 2015 Feb 26.

Department of Chemical & Materials Engineering, New Mexico State University, MSC 3805 P.O. Box 30001, Las Cruces, NM 88003-8001, USA.

Flow cytometry is a powerful means for in vitro cellular analyses where multi-fluorescence and multi-angle light scattering can indicate unique biochemical or morphological features of single cells. Yet, to date, flow cytometry systems have lacked the ability to capture complex fluorescence dynamics due to the transient nature of flowing cells. In this contribution we introduce a simple approach for measuring multiple fluorescence lifetimes from a single cytometric event. We leverage square wave modulation, Fourier analysis, and high frequency digitization and show the ability to resolve more than one fluorescence lifetime from fluorescently-labelled cells and microspheres. Illustration of a flow cytometer capable of capturing multiple fluorescence lifetime measurements; creating potential for multi-parametric, time-resolved signals to be captured for every color channel.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jbio.201400115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4869968PMC
November 2015

Maternal Attachment Buffers the Association Between Exposure to Violence and Youth Attitudes About Aggression.

J Clin Child Adolesc Psychol 2016 Sep-Oct;45(5):605-613. Epub 2015 Feb 6.

a Department of Psychology , Marquette University.

The present study examined the relative and cumulative predictive power of parent-child, interparental, and community aggression on youths' perceptions of the acceptability of aggression between peers and siblings. The potential for mother-child attachment to buffer the effects of violence on aggressive attitudes was tested, as well as the link between aggressive attitudes and aggressive behaviors. A diverse sample of 148 children (ages 9-14) completed measures of interparental, parent-child, and community aggression; a measure of mother-child attachment quality; and a measure of aggressive behaviors. Participants also rated the acceptability of aggressive interactions between two peers and two siblings in written vignettes. Mothers completed a measure of their child's aggressive behaviors. Youths' violence exposure was related to perceptions of aggression as more acceptable, with parent-child aggression having the only unique association. Maternal attachment buffered the relation between exposure to community violence and perceived acceptability of aggression, which predicted decreased aggression. When exposed to high levels of community violence, youths with more secure maternal attachment perceived aggression as less acceptable than youths with less secure attachment and, in turn, displayed fewer aggressive behaviors. Interventions that focus on strengthening the caregiver-child relationship in children exposed to violence may reduce aggressive behaviors by interrupting the development of aggressive attitudes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/15374416.2014.987380DOI Listing
June 2017

Measuring and sorting cell populations expressing isospectral fluorescent proteins with different fluorescence lifetimes.

PLoS One 2014 10;9(10):e109940. Epub 2014 Oct 10.

Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.

Study of signal transduction in live cells benefits from the ability to visualize and quantify light emitted by fluorescent proteins (XFPs) fused to different signaling proteins. However, because cell signaling proteins are often present in small numbers, and because the XFPs themselves are poor fluorophores, the amount of emitted light, and the observable signal in these studies, is often small. An XFP's fluorescence lifetime contains additional information about the immediate environment of the fluorophore that can augment the information from its weak light signal. Here, we constructed and expressed in Saccharomyces cerevisiae variants of Teal Fluorescent Protein (TFP) and Citrine that were isospectral but had shorter fluorescence lifetimes, ∼ 1.5 ns vs ∼ 3 ns. We modified microscopic and flow cytometric instruments to measure fluorescence lifetimes in live cells. We developed digital hardware and a measure of lifetime called a "pseudophasor" that we could compute quickly enough to permit sorting by lifetime in flow. We used these abilities to sort mixtures of cells expressing TFP and the short-lifetime TFP variant into subpopulations that were respectively 97% and 94% pure. This work demonstrates the feasibility of using information about fluorescence lifetime to help quantify cell signaling in living cells at the high throughput provided by flow cytometry. Moreover, it demonstrates the feasibility of isolating and recovering subpopulations of cells with different XFP lifetimes for subsequent experimentation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109940PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4193854PMC
June 2015

Expanding the potential of standard flow cytometry by extracting fluorescence lifetimes from cytometric pulse shifts.

Cytometry A 2014 Dec 1;85(12):999-1010. Epub 2014 Oct 1.

Department of Chemical Engineering, New Mexico State University, Las Cruces, New Mexico, 88003-001.

Fluorescence lifetime measurements provide information about the fluorescence relaxation, or intensity decay, of organic fluorophores, fluorescent proteins, and other inorganic molecules that fluoresce. The fluorescence lifetime is emerging in flow cytometry and is helpful in a variety of multiparametric, single cell measurements because it is not impacted by nonlinearity that can occur with fluorescence intensity measurements. Yet time-resolved cytometry systems rely on major hardware modifications making the methodology difficult to reproduce. The motivation of this work is, by taking advantage of the dynamic nature of flow cytometry sample detection and applying digital signal processing methods, to measure fluorescence lifetimes using an unmodified flow cytometer. We collect a new lifetime-dependent parameter, referred to herein as the fluorescence-pulse-delay (FPD), and prove it is a valid representation of the average fluorescence lifetime. To verify we generated cytometric pulses in simulation, with light emitting diode (LED) pulsation, and with true fluorescence measurements of cells and microspheres. Each pulse is digitized and used in algorithms to extract an average fluorescence lifetime inherent in the signal. A range of fluorescence lifetimes is measurable with this approach including standard organic fluorophore lifetimes (∼1 to 22 ns) as well as small, simulated shifts (0.1 ns) under standard conditions (reported herein). This contribution demonstrates how digital data acquisition and signal processing can reveal time-dependent information foreshadowing the exploitation of full waveform analysis for quantification of similar photo-physical events within single cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cyto.a.22574DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4257068PMC
December 2014

Fluorescence lifetime excitation cytometry by kinetic dithering.

Electrophoresis 2014 Jul 12;35(12-13):1846-54. Epub 2014 May 12.

Department of Chemical Engineering, College of Engineering, New Mexico State University, Las Cruces, NM, USA.

Flow cytometers are powerful high-throughput devices that capture spectroscopic information from individual particles or cells. These instruments provide a means of multi-parametric analyses for various cellular biomarkers or labeled organelles and cellular proteins. However, the spectral overlap of fluorophores limits the number of fluorophores that can be used simultaneously during experimentation. Time-resolved parameters enable the quantification of fluorescence decay kinetics, thus circumventing common issues associated with intensity-based measurements. This contribution introduces fluorescence lifetime excitation cytometry by kinetic dithering (FLECKD) as a method to capture multiple fluorescence lifetimes using a hybrid time-domain approach. The FLECKD approach excites fluorophores by delivering short pulses of light to cells or particles by rapid dithering and facilitates measurement of complex fluorescence decay kinetics by flow cytometry. Our simulations demonstrated a resolvable fluorescence lifetime value as low as 1.8 ns (±0.3 ns) with less than 20% absolute error. Using the FLECKD instrument, we measured the shortest average fluorescence lifetime value of 2.4 ns and found the system measurement error to be ±0.3 ns (SEM), from hundreds of monodisperse and chemically stable fluorescent microspheres. Additionally, we demonstrate the ability to detect two distinct excited state lifetimes from fluorophores in single cells using FLECKD. This approach presents a new ability to resolve multiple fluorescence lifetimes while retaining the fluidic throughput of a cytometry system. The ability to discriminate more than one average fluorescence lifetime expands the current capabilities of high-throughput and intensity-based cytometry assays as the need to tag one single cell with multiple fluorophores is now widespread.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/elps.201300618DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4231566PMC
July 2014

Subcellular localization-dependent changes in EGFP fluorescence lifetime measured by time-resolved flow cytometry.

Biomed Opt Express 2013 19;4(8):1390-400. Epub 2013 Jul 19.

Molecular Biology Program, New Mexico State University, Las Cruces, NM 88003, USA.

Intracellular protein transport and localization to subcellular regions are processes necessary for normal protein function. Fluorescent proteins can be fused to proteins of interest to track movement and determine localization within a cell. Currently, fluorescence microscopy combined with image processing is most often used to study protein movement and subcellular localization. In this contribution we evaluate a high-throughput time-resolved flow cytometry approach to correlate intracellular localization of human LC3 protein with the fluorescence lifetime of enhanced green fluorescent protein (EGFP). Subcellular LC3 localization to autophagosomes is a marker of the cellular process called autophagy. In breast cancer cells expressing native EGFP and EGFP-LC3 fusion proteins, we measured the fluorescence intensity and lifetime of (i) diffuse EGFP (ii) punctate EGFP-LC3 and (iii) diffuse EGFP-ΔLC3 after amino acid starvation to induce autophagy-dependent LC3 localization. We verify EGFP-LC3 localization with low-throughput confocal microscopy and compare to fluorescence intensity measured by standard flow cytometry. Our results demonstrate that time-resolved flow cytometry can be correlated to subcellular localization of EGFP fusion proteins by measuring changes in fluorescence lifetime.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/BOE.4.001390DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3756581PMC
September 2013

Association of a reduction in central obesity and phosphorus intake with changes in urinary albumin excretion: the PREMIER study.

Am J Kidney Dis 2013 Nov 28;62(5):900-7. Epub 2013 Jun 28.

Division of Nephrology, Johns Hopkins University, Baltimore, MD; Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University, Baltimore, MD. Electronic address:

Background: Excess adiposity and dietary factors may be important determinants of urinary albumin excretion (UAE).

Study Design: Observational analysis of PREMIER, a randomized trial designed to lower blood pressure using behavioral interventions (counseling on weight loss, healthy diet, and exercise).

Setting & Participants: 481 participants with normal kidney function who provided adequate 24-hour urine collections at baseline and 6 months.

Predictors: Change in waist circumference; 24-hour urine sodium, potassium, and phosphorus excretion; and protein intake estimated from urea nitrogen.

Outcomes & Measurements: The primary outcome was change in log-transformed 24-hour UAE over 6 months.

Results: After 6 months, the proportion of individuals with UAE ≥10 mg/d decreased from 18.7% to 12.7% (P < 0.001). Changes in mean waist circumference (-4.2 ± 6.6 [SD] cm), 24-hour excretion of sodium (-28.2 ± 71.7 mmol/d), potassium (+8.4 ± 27.8 mmol/d), phosphorus (-27.7 ± 314.1 mg/d), and protein intake (-1.7 ± 19.4 g/d) were observed. After adjustment for relevant covariates, the following variables were associated significantly with reduction in ln(UAE) in separate models: decrease in waist circumference (P = 0.001), decrease in 24-hour urine phosphorus excretion (P < 0.001), and decrease in protein intake (P = 0.01). In a multivariable model including these 3 predictors, decreases in waist circumference (P = 0.002) and 24-hour urine phosphorus excretion (P = 0.03), but not change in protein intake (P = 0.5), remained associated significantly with reduction in ln(UAE). These associations remained significant even after adjustment for changes in blood pressure and insulin resistance. Baseline UAE and metabolic syndrome modified the relationship of waist circumference with ln(UAE); specifically, individuals with higher UAE and baseline metabolic syndrome experienced greater reductions in ln(UAE) from decreases in waist circumference.

Limitations: Observational study with potential for confounding.

Conclusions: In adults with normal kidney function, decreases in waist circumference and 24-hour urine phosphorus excretion are associated with reductions in UAE. These findings support the rationale for clinical trials to determine whether reducing dietary phosphorus intake or waist circumference could prevent chronic kidney disease or slow its progression.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1053/j.ajkd.2013.04.022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3809322PMC
November 2013

Cytometric sorting based on the fluorescence lifetime of spectrally overlapping signals.

Opt Express 2013 Jun;21(12):14816-31

Department of Chemical Engineering, New Mexico State University, Las Cruces, NM 88003-001, USA.

Flow cytometry is a well-established and powerful high- throughput fluorescence measurement tool that also allows for the sorting and enrichment of subpopulations of cells expressing unique fluorescence signatures. Owing to the reliance on intensity-only signals, flow cytometry sorters cannot easily discriminate between fluorophores that spectrally overlap. In this paper we demonstrate a new method of cell sorting using a fluorescence lifetime-dependent methodology. This approach, referred to herein as phase-filtered cell sorting (PFCS), permits sorting based on the average fluorescence lifetime of a fluorophore by separating fluorescence signals from species that emit differing average fluorescence lifetimes. Using lifetime-dependent hardware, cells and microspheres labeled with fluorophores were sorted with purities up to 90%. PFCS is a practical approach for separating populations of cells that are stained with spectrally overlapping fluorophores or that have interfering autofluorescence signals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3726248PMC
http://dx.doi.org/10.1364/OE.21.014816DOI Listing
June 2013

Associations between fibroblast growth factor 23 and cardiac characteristics in pediatric heart failure.

Pediatr Nephrol 2013 Oct 6;28(10):2035-42. Epub 2013 Jun 6.

Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, 1120 NW 14th St., Miami, FL 33136, USA.

Background: In adults with heart failure, elevated levels of fibroblast growth factor 23 (FGF23) are associated with mortality. Data on FGF23 levels in pediatric heart failure are lacking.

Patients And Methods: We conducted a cross-sectional study of 17 healthy children (mean age 13 years) and 20 pediatric patients with heart failure (mean age 12 years) who underwent echocardiography and for whom the following measurements were taken: plasma FGF23 and parathyroid hormone (PTH) and serum phosphate, creatinine and N-terminal prohormone brain natriuretic peptide (NT-proBNP). Symptom severity was assessed with the New York Heart Association and the Ross classification systems.

Results: Of the 20 patients, 11 had dilated cardiomyopathy, four had congenital heart disease, three had hypertrophic cardiomyopathy, one had a failing heart transplant and one had pulmonary hypertension. Mean phosphate levels in these patients were within the reported reference range for healthy children. Median PTH levels were in the normal range in patients and controls. The median FGF23 level was higher in patients versus controls (110.9 vs. 66.4 RU/ml; P = 0.03) and higher in patients on diuretics versus other patients (222.4 vs. 82.1 RU/ml; P = 0.01). Levels of FGF23 and NT-proBNP were directly correlated (r = 0.47, P = 0.04), and patients with greater physical functional impairment had higher FGF23 levels (142.5 in those with moderate-severe limitation vs. 92.8 RU/ml in those with no limitation; P = 0.05). Among patients with dilated cardiomyopathy, higher FGF23 levels were associated with a greater left ventricular end-diastolic diameter (r = 0.63, P = 0.04).

Conclusion: FGF23 levels are elevated in children with heart failure and are associated with diuretic use, severity of heart failure and left ventricular dilation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00467-013-2515-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3755096PMC
October 2013

Effects of dietary phosphate restriction and phosphate binders on FGF23 levels in CKD.

Clin J Am Soc Nephrol 2013 Jun 7;8(6):1009-18. Epub 2013 Mar 7.

Division of Nephrology and Hypertension, Department of Medicine, Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, Florida 33136, USA.

Background: Elevated levels of fibroblast growth factor 23 (FGF23) are associated with increased risk of adverse outcomes in patients with CKD. Reducing dietary phosphate intake or absorption may decrease FGF23 levels, but data on the combined effects of dietary phosphate restriction and phosphate binders in CKD are limited.

Design, Setting, Participants, & Measurements: In this 2×2 factorial, single-blinded, placebo-controlled, 3-month study, conducted between July 2009 and March 2012, 39 patients with CKD stages 3 or 4 and normal serum phosphate levels were randomly assigned to one of four groups: ad libitum diet plus lanthanum carbonate (LC) placebo (n=10), 900-mg phosphate diet plus LC placebo (n=10), ad libitum diet plus LC (n=11), or 900-mg phosphate diet plus LC (n=8). The dose of LC was 1000 mg three times daily with meals. Dietary restriction was accomplished with outpatient counseling. The primary end point was change in FGF23 levels from baseline.

Results: Compared with ad libitum diet, the 900-mg phosphate diet did not significantly reduce FGF23 levels (diet × time interaction, P=0.05). Compared with placebo, LC alone also did not significantly reduce FGF23 levels (LC × time interaction, P=0.21). However, the dual intervention significantly decreased FGF23 levels throughout the study period (diet × LC × time interaction, P=0.02), resulting in a 35% (95% confidence interval, 8%-62%) reduction by study end.

Conclusion: The combination of LC plus counseling for a phosphate-restricted diet decreased FGF23 levels in patients with CKD stages 3-4 and normal serum phosphate levels.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2215/CJN.09250912DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3675851PMC
June 2013

Associations of dietary phosphorus intake, urinary phosphate excretion, and fibroblast growth factor 23 with vascular stiffness in chronic kidney disease.

J Ren Nutr 2013 Jan 9;23(1):12-20. Epub 2012 Mar 9.

Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida, USA.

Objective: Elevated serum phosphate concentrations are established risk factors for cardiovascular disease and mortality in chronic kidney disease (CKD). Independent associations of other indices of phosphorus metabolism, such as phosphorus intake, urinary phosphate excretion, or hormones that regulate these systems, like fibroblast growth factor 23 (FGF23), with markers of cardiovascular disease in CKD, have been studied in less detail.

Design: Cross-sectional study.

Participants: Seventy-four adult CKD patients with mean creatinine clearance of 51 ± 19 mL/minute.

Outcome: Augmentation index (AI)--a surrogate marker of arterial stiffness.

Results: Although serum phosphate varied little across quartiles of creatinine clearance, average daily phosphorus intake and 24-hour urinary phosphate excretion decreased from highest to lowest quartile (by 31% and 60%, respectively, P for trend <.05). FGF23 was associated with serum phosphate (r = 0.24, P = .03) and creatinine clearance (r = -0.4, P = .001), but not with dietary phosphorus or 24-hour urinary phosphate excretion (P > .05 for both). Older age, higher systolic blood pressure, female gender, and black race were independently associated with increased AI. In contrast, there were no associations of serum phosphate, dietary phosphorus intake, urinary phosphate excretion, or FGF23 with AI in multivariate-adjusted models.

Conclusions: In this sample of patients with CKD, established risk factors for arterial stiffness, but not mediators of phosphorus metabolism, were associated with increased AI. In addition, there were no significant associations between FGF23 and dietary phosphorus or urinary phosphate excretion. Future studies are needed to determine the main factors associated with elevations in FGF23 in CKD and to further assess the association of disordered phosphorus metabolism with subclinical markers of vascular disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1053/j.jrn.2011.12.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3378791PMC
January 2013

Capture of Fluorescence Decay Times by Flow Cytometry.

Curr Protoc Cytom 2012 ;59(125):1.25.1-1.25.21

National Flow Cytometry Resource, Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545.

In flow cytometry, the fluorescence decay time of an excitable species has been largely underutilized and is not likely found as a standard parameter on any imaging cytometer, sorting, or analyzing system. Most cytometers lack fluorescence lifetime hardware mainly owing to two central issues. Foremost, research and development with lifetime techniques has lacked proper exploitation of modern laser systems, data acquisition boards, and signal processing techniques. Secondly, a lack of enthusiasm for fluorescence lifetime applications in cells and with bead-based assays has persisted among the greater cytometry community. In this unit, we describe new approaches that address these issues and demonstrate the simplicity of digitally acquiring fluorescence relaxation rates in flow. The unit is divided into protocol and commentary sections in order to provide a most comprehensive discourse on acquiring the fluorescence lifetime with frequency-domain methods. The unit covers (i) standard fluorescence lifetime acquisition (protocol-based) with frequency-modulated laser excitation, (ii) digital frequency-domain cytometry analyses, and (iii) interfacing fluorescence lifetime measurements onto sorting systems. Within the unit is also a discussion on how digital methods are used for aliasing in order to harness higher frequency ranges. Also, a final discussion is provided on heterodyning and processing of waveforms for multi-exponential decay extraction.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/0471142956.cy0125s59DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4240630PMC
January 2012