GALVESTON, TX, United States
GALVESTON, TX, United States
SEARCH FILTERS
Time filter
Source Type

Riberdy V.A.,University of Windsor | Frederickson C.J.,Neurobiotex, Inc. | Frederickson C.J.,University of Texas | Rehse S.J.,University of Windsor
Applied Spectroscopy | Year: 2017

The absolute concentration of Zn in human fingernail clippings was determined ex vivo using 1064 nm laser-induced breakdown spectroscopy and confirmed by speciated isotope dilution mass spectrometry. A nail testing protocol that sampled across the nail (perpendicular to the direction of growth) was developed and validated by scanning electron microscopy energy-dispersive X-ray spectrometry. Using this protocol, a partial least squares (PLS) regression model predicted the Zn concentration in the fingernails of five people to within an average of 7 ppm. The variation in the Zn concentration with depth into the nail determined by laser-induced breakdown spectroscopy was studied and showed no systematic variation for up to 15 subsequent laser pulses in one location. The effects of nail hydration (dehydrated and over-hydrated) and nail surface roughness were investigated to explain an anomalously large scatter observed in the measurements. This scatter was attributed to the layered nature and fibrous structure of the fingernails, which resulted in non-uniform ablation as determined by scanning electron microscopy. This work demonstrates that a protocol consisting of low pulse energy (<10 mJ) 1064 nm laser pulses incident on human fingernail clippings in an Ar environment can produce quantifiable Zn emission in the laser-induced plasma and that the measured Zn intensity can be used to accurately predict the Zn concentration in human fingernails. © Society for Applied Spectroscopy.


Bozym R.A.,University of Maryland Baltimore County | Bozym R.A.,University of Pittsburgh | Chimienti F.,CEA Grenoble | Giblin L.J.,Neurobiotex, Inc. | And 9 more authors.
Experimental Biology and Medicine | Year: 2010

The zinc(II) ion has recently been implicated in a number of novel functions and pathologies in loci as diverse as the brain, retina, small intestine, prostate, heart, pancreas, and immune system. Zinc ions are a required nutrient but elevated concentrations are known to kill cells in vitro. Paradoxical observations regarding zinc's effects have appeared frequently in the literature, and often their physiological relevance is unclear. We found that for PC-12, HeLa and HT-29 cell lines as well as primary cultures of cardiac myocytes and neurons in vitro in differing media, approximately 5 nmol/L free zinc (pZn = 8.3, where pZn is defined as - log10 [free Zn 2+]) produced apparently healthy cells, but 20-fold higher or (in one case) lower concentrations were usually harmful as judged by multiple criteria. These results indicate that (1) the free zinc ion levels of media should be controlled with a metal ion buffer; (2) adding zinc or strong zinc ligands to an insufficiently buffered medium may lead to unpredictably low or high free zinc levels that are often harmful to cells; and (3) it is generally desirable to measure free zinc ion levels due to the presence of contaminating zinc in many biochemicals and unknown buffering capacity of many media. Copyright © 2010 by the Society for Experimental Biology and Medicine.


Zhang D.Y.,Massachusetts Institute of Technology | Azrad M.,University of Alabama at Birmingham | Demark-Wahnefried W.,University of Alabama at Birmingham | Frederickson C.J.,Neurobiotex, Inc. | And 2 more authors.
ACS Chemical Biology | Year: 2015

Small-molecule fluorescent sensors are versatile agents for detecting mobile zinc in biology. Capitalizing on the abundance of validated mobile zinc probes, we devised a strategy for repurposing existing intensity-based sensors for quantitative applications. Using solid-phase peptide synthesis, we conjugated a zinc-sensitive Zinpyr-1 derivative and a zinc-insensitive 7-hydroxycoumarin derivative onto opposite ends of a rigid P9K peptide scaffold to create HcZ9, a ratiometric fluorescent probe for mobile zinc. A plate reader-based assay using HcZ9 was developed, the accuracy of which is comparable to that of atomic absorption spectroscopy. We investigated zinc accumulation in prostatic cells and zinc levels in human seminal fluid. When normal and tumorigenic cells are bathed in zinc-enriched media, cellular mobile zinc is buffered and changes slightly, but total zinc levels increase significantly. Quantification of mobile and total zinc levels in human seminal plasma revealed that the two are positively correlated with a Pearsons coefficient of 0.73. © 2014 American Chemical Society.


Mei Y.,University of New Mexico | Frederickson C.J.,Neurobiotex, Inc. | Giblin L.J.,Neurobiotex, Inc. | Weiss J.H.,University of California at Irvine | And 2 more authors.
Chemical Communications | Year: 2011

A new class of in vitro Zn(ii) chemosensor based on dipyrrin has been developed. 5-(Pyren-1-yl)-4,6-dipyrrin (PYDPY1) was synthesized and exhibited high selectivity and sensitivity to Zn(ii) (Kd of 20 μM) compared to other metal ions. PYDPY1 was applied to the visualization of Zn(ii) concentration in hippocampal tissue. © 2011 The Royal Society of Chemistry.


Neurobiotex, Inc. | Entity website

Tutorials Showing page 1 of 1 pages


Neurobiotex, Inc. | Entity website


Neurobiotex, Inc. | Entity website

Page is Under Construction !


Neurobiotex, Inc. | Entity website


Neurobiotex, Inc. | Entity website

Home -> Zinc-buffers and Media Showing page 1 of 1 pages


Neurobiotex, Inc. | Entity website

Home -> Zinc Stains and Probes Showing page 1 of 1 pages

Loading Neurobiotex, Inc. collaborators
Loading Neurobiotex, Inc. collaborators