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J A Caruso

Publications and source records attributed to J A Caruso.

At least 19 recordsLinked to original sources
PubMed2006

Selenium speciation analysis using inductively coupled plasma-mass spectrometry.

Selenium exists in several oxidation states and a variety of inorganic and organic compounds, and the chemistry of selenium is complex in both the environment and living systems. Selenium is an essential element at trace levels and toxic at greater levels. Interest in speciation analysis for selenium has grown rapidly in this last decade, especially in the use of chromatographic separation coupled with inductively coupled plasma-mass spectrometry (ICP-MS). Complete characterization of selenium compounds is necessary to understand selenium's significance in metabolic processes, clinical chemistry, biology, toxicology, nutrition and the environment. This review describes some of the essential background of selenium, and more importantly, some of the currently used separation methodologies, both chromatographic and electrophoretic, with emphasis on applications of selenium speciation analysis using ICP-MS detection.

Chromatography, Gas↗
PubMed2004

Arsenic and its speciation analysis using high-performance liquid chromatography and inductively coupled plasma mass spectrometry.

It is known that arsenic has different toxicological properties dependent upon both its oxidation state for inorganic compounds, as well as the different toxicity levels exhibited for organic arsenic compounds. The field of arsenic speciation analysis has grown rapidly in recent years, especially with the utilization of high-performance liquid chromatography (HPLC) coupled to inductively coupled plasma mass spectrometry (ICP-MS), a highly sensitive and robust detector system. Complete characterization of arsenic compounds is necessary to understand intake, accumulation, transport, storage, detoxification and activation of this element in the natural environment and living systems. This review describes the essential background and toxicity of arsenic in the environment, and more importantly, some currently used chromatographic applications and sample handling procedures necessary to accurately detect and quantify arsenic in its various chemical forms. Applications and work using only HPLC-ICP-MS for arsenic speciation of environmental and biological samples are presented in this review.

Arsenic↗
PubMed2002

Release of cytochrome c and activation of pro-caspase-9 following lysosomal photodamage involves Bid cleavage.

Photodynamic therapy (PDT) protocols employing lysosomal sensitizers induce apoptosis via a mechanism that causes cytochrome c release prior to loss of mitochondrial membrane potential (DeltaPsi(m)). The current study was designed to determine how lysosomal photodamage initiates mitochondrial-mediated apoptosis in murine hepatoma 1c1c7 cells. Fluorescence microscopy demonstrated that the photosensitizer N-aspartyl chlorin e6 (NPe6) localized to the lysosomes. Irradiation of cultures preloaded with NPe6 induced the rapid destruction of lysosomes, and subsequent cleavage/activation of Bid, pro-caspases-9 and -3. Pro-caspase-8 was not activated. Release of cytochrome c occurred at about the time of Bid cleavage and preceded the loss of DeltaPsi(m). Extracts of purified lysosomes catalyzed the in vitro cleavage of cytosolic Bid, but not pro-caspase-3 activation. Pharmacological inhibition of cathepsin B, L and D activities did not suppress Bid cleavage or pro-caspases-9 and -3 activation. These studies demonstrate that photodamaged lysosomes trigger the mitochondrial apoptotic pathway by releasing proteases that activate Bid.

Animals↗
PubMed2002

SEC-ICP-MS studies for elements binding to different molecular weight fractions of humic substances in compost extract obtained from urban solid waste.

In this work, the speciation of elements in compost was studied with emphasis on their binding to humic substances. In order to assess the distribution of As, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, U, Th and Zn among molecular weight fractions of humic substances, the compost extract (extracted by 0.1 mol l(-1) sodium pyrophosphate) was analyzed by size exclusion chromatography coupled on-line with UV-Vis spectrophotometric and ICP-MS detection. Similar chromatograms were obtained for standard humic acid (Fluka) and for compost extract (254 nm, 400 nm) and three size fractions were operationally defined that corresponded to the apparent molecular weight ranges > 15 kDa, 1-15 kDa and < 1 kDa. The percentage of total element content in compost that was leached to the extract ranged from 30% up to 100% for different elements. The elution profiles of Co, Cr, Cu, Ni and Pb (ICP-MS) followed that of humic substances, while for other elements the bulk elution peak matched the retention time observed for the element in the absence of compost extract. Spiking experiments were carried out to confirm elements' binding and to estimate the affinity of individual elements for humic substances derived from compost. The results obtained indicated the following order of decreasing affinity: Cu > Ni > Co > Pb > Cd > (Cr, U, Th) >> (As, Mn, Mo, Zn). After standard addition, further binding of Cu, Ni and Co with the two molecular weight fractions of humic substances was observed, indicating that humic substances derived from compost were not saturated with these elements.

Chromatography, Gel↗
PubMed2002

Selenium incorporation into Saccharomyces cerevisiae cells: a study of different incorporation methods.

AIMS: To study the effects of the selenium enrichment protocols in yeast at various points in the cell cycle, total selenium accumulation and the forms of selenium incorporated. METHODS AND RESULTS: The use of selenized yeast as enriched selenium supplements in human nutrition has become a topic of increasing interest over the last decade. Four enrichment procedures have been evaluated using sodium selenite as the selenium source: enrichment during the growth phase; enrichment at the non-growth phase, both of these at different selenium levels; enrichment by seeding in a fermentable carbon source (glucose); Se-enrichment with a non-fermentable carbon source (glycerol). A nitric acid digestion of the yeast samples prepared under different conditions has been performed in order to evaluate the total selenium incorporated into the yeast cells. Also, an enzymatic digestion of the yeast samples with pepsin has been carried out as an initial step to begin the process of determining which of the different possible selenium species are formed. The cell count evaluations of the selenium-enriched yeast showed that the growth phase, seeding and the use of YEPG media is influenced by the addition of Se, while the non-growth phase is not. Total selenium incorporation studies showed that seeding the yeast permits more accumulation of selenium. Speciation studies of the enriched yeast showed that the growth phase increases the formation of L-Se-methionine. CONCLUSIONS: When the aim of enriching yeast with selenium is the formation of L-Se-methionine, the best enrichment procedure is using the growth phase with small concentrations of sodium selenite. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of selenium supplements is widespread and most of the supplements use selenium-enriched yeast in their formulation. Studies made on supplements do not have the appropriate Se-species for optimal absorption in the human body. This study presents and compares methods for the best selenium yeast enrichment that could ultimately be used in selenium supplement formulations.

Colony Count, Microbial↗
PubMed2001

Genetic alteration of chromosome 8 is a common feature of human mammary epithelial cell lines transformed in vitro with benzo[a]pyrene.

While some epidemiological risk factors for breast cancer have been identified, the environmental factors responsible for transformation of mammary epithelial cells are not clear. We have exposed the spontaneously immortalized human mammary epithelial cell line MCF-10A to benzo[a]pyrene and selected transformed clones based on a loss of contact inhibition and anchorage-dependent growth. Cytogenetic studies showed that each of the transformed sublines possess an isochromosome 8q aberration. The c-Myc proto-oncogene, which is positioned at 8q24, was analyzed for changes in expression. Both c-Myc mRNA and protein levels were increased in the transformed clones relative to the parental cells. The transformed clones were not able to grow as tumors in vivo when injected into nude or SCID mice. To determine whether the involvement of chromosome 8 in BP-induced mutagenesis was a reproducible event, transformed clones were selected from three additional independently treated sets of BP-exposed MCF-10A cultures and analyzed by spectral karyotyping (SKY). These transformed sublines also harbored the isochromosome 8q abnormality. Data from this model show that benzo[a]pyrene, a ubiquitous procarcinogen, can induce selectable morphologic changes in a human mammary epithelial cell line, and that these transformed cells possess chromosomal aberrations frequently found in human breast tumors.

Animals↗
PubMed2001

An evaluation of extraction techniques for arsenic species from freeze-dried apple samples.

The extraction of arsenic from freeze-dried apples and subsequent determination of individual arsenic species by HPLC-ICP-MS is described. Solvent extraction with sonication using various aqueous and aqueous/solvent mixtures was initially evaluated by measuring total arsenic extracted by ICP-MS. A two step procedure using overnight treatment with alpha-amylase enzyme followed by sonication for 6 h with 40:60 acetonitrile-water was found to provide good extraction efficiency. The concentration of arsenic extracted was compared with the concentration of total arsenic in the samples determined using ICP-MS after microwave digestion in order to calculate extraction efficiency. Individual arsenic species in the extracts were measured using HPLC-ICP-MS. The three most abundant arsenic species found were arsenite, arsenate and dimethylarsinic acid. Total arsenic concentrations in the freeze-dried apple samples ranged from 8.2 to 80.9 micrograms kg-1 As, dry mass. By HPLC-ICP-MS, the relative amount of inorganic arsenic in the samples ranged from 73 to 90% of the sum of the arsenic species detected in each sample.

Arsenicals↗
PubMed2000

Potentiation of photodynamic therapy by ursodeoxycholic acid.

Ursodeoxycholic acid (UDCA) protects cells from the apoptotic effects of hydrophobic bile acids and some other cytotoxic agents. We observed the opposite result when assessing the effects of UDCA on the apoptotic response to mitochondrial photodamage induced by photodynamic therapy (PDT). Two photosensitizers with predominantly mitochondrial specificity were used: a porphycene we have designated CPO; and the tin etiopurpurin SnET2. UDCA potentiated the loss of mitochondrial potential, release of cytochrome c into the cytosol, activation of caspase-3, and apoptotic cell death after irradiation of photosensitized murine leukemia L1210 or hepatoma 1c1c7 cells. These effects were not observed when UDCA was added after irradiation. Glyco-UDCA and tauro-UDCA, conjugated forms of UDCA that are formed in vivo, were as effective as UDCA in promoting PDT phototoxicity. Because UDCA does not act by enhancing intracellular accumulation of the photosensitizing agents used in this study, we propose that the mode of action of UDCA involves the sensitization of mitochondrial membranes to photodamage. UDCA is used currently in gastroenterology for several indications. The drug may offer a means for promoting the efficacy of PDT with minimal adverse effects.

Animals↗
PubMed2000

Separation of metalloporphyrins by capillary electrophoresis with UV detection and inductively coupled plasma mass spectrometric detection.

Vitamin B12, cobalt protoporphyrin, manganese protoporphyrin, and zinc protoporphyrin were separated using capillary electrophoresis, and a comparison was made between detection with inductively coupled plasma mass spectrometry (ICP-MS) and UV detection. Absolute limits of detection were slightly better with ICP-MS detection than with UV detection, but for both methods absolute detection limits were in the picogram range. The migration times of the analytes decreased by several minutes when ICP MS detection was employed, and this phenomenon was believed to be a result of a "suction effect" that developed when the CE capillary was interfaced to the ICP-MS nebulizer. However, the resolution between species containing the same metal atom was not altered significantly, and the separation was completed in much less time relative to separations performed with UV detection.

Electrophoresis, Capillary↗
PubMed2000

Element selective detection for supercritical-fluid chromatography.

This manuscript describes the use of Supercritical-Fluid Chromatography (SFC) with plasma spectrometric detection for the analysis of organometallics. An introduction on the principles and characteristics of Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) is included, along with a discussion about requirements for coupling SFC to plasma detection and the different approaches for interfacing SFC to ICP. The last part of this review paper provides a comprehensive description of SFC-ICP applications for the analysis of organometallics containing iron, silicon, tin, chromium, arsenic, lead, mercury and antimony.

Antimony↗
PubMed2000

Development of chiral HPLC for selenoamino acids with ICP-MS detection:application to selenium nutritional supplements.

The enantiomeric separation of three underivatized seleno-amino acids, D,L-selenocystine, and D,L-selenomethionine, and D,L-selenomethionine, with UV and ICP-MS detection is described. An HPLC column with a chiral crown ether stationary phase and a mobile phase of 0.10 M HCIO4 was used. Absolute detection limits obtained with UV detection ranged from 34.5 to 47.1 ng whereas those obtained with the plasma detector were ca. 40-400 times better. The separations with either detector were good, with the little detector effect on the resolution. Ten commercially available dietary selenium supplements were analyzed using the chiral column to identify and quantify the selenium species present with both detection modes. Selenium species were easily identified using ICP-MS detection, whereas UV detection was not viable because of interferences from the sample matrix and inadequate sensitivity. Selenium species that were unretained using the chiral column were identified using anion exchange chromatography. Total amounts in the samples were also measured using a conventional digestion and enzymatic digestion with ICP-MS detection.

Chromatography, High Pressure Liquid↗
PubMed2000

A comparison of vancomycin and sulfated beta-cyclodextrin as chiral selectors for enantiomeric separations of selenoamino acids using capillary electrophoresis with UV absorbance detection.

The enantiomeric separation of three selenoamino acids, D,L-selenomethionine, D,L-selenoethionine and D,L-selenocystine is described. Both sulfated beta-cyclodextrin and vancomycin have been successfully used to separate all enantiomers of the compounds with UV detection. Reproducible separations, in terms of peak area and migration time were obtained using sulfated beta-cyclodextrin with reversed polarity and UV detection. With vancomycin as a chiral selector, reversed polarity was found to be more reproducible than positive polarity in terms of peak migration times.

Cystine↗
PubMed1999

Role of HSP90 in mediating cross-talk between the estrogen receptor and the Ah receptor signal transduction pathways.

Tetrachlorodibenzo-p-dioxin (TCDD)-mediated gene transactivation via the Ah receptor (AhR) has been shown to be dependent upon estrogen receptor (ER) expression in human breast cancer cells. We have investigated the 90-kDa heat shock protein (HSP90) as a mediator of cross-talk between the AhR and the ER signal transduction pathways. The effect of HSP90 overexpression on receptor activity was determined by transient transfection assays using a HSP90 expression vector. Ligand-inducible gene expression was inhibited when the HSP90 expression vector was cotransfected with a TCDD-responsive reporter plasmid. However, overexpression of HSP90 did not block induction of an estrogen-responsive reporter plasmid. To determine whether ER facilitates AhR signaling through its ability to squelch HSP90, two vectors expressing protein products that bind HSP90 were transfected into MDA-MB-231 cells. Introduction of (i) He11, an ER deletion mutant that does not bind DNA, and (ii) the ligand-binding domain of human AhR, both led to increased basal and TCDD-inducible CYP1A1 expression. Finally, the subcellular distribution of HSP90 was investigated in human breast cancer cell lines. These studies showed HSP90 to be primarily cytoplasmic in ER-positive cell lines, whereas in matched ER-negative cell lines HSP90 was distributed equally between the cytoplasm and nucleus. Taken together, these results demonstrate that HSP90 can regulate AhR activity in vivo, and that Ah-responsiveness is dependent upon cellular ER content through a mechanism that involves HSP90.

Breast Neoplasms↗
PubMed1999

Liquid chromatography-inductively coupled plasma mass spectrometry.

The technique of coupling liquid chromatography to inductively plasma mass spectrometry (ICP-MS) is reviewed. A brief introduction to the ICP-MS instrument is given as well as methods to couple the two analytical instruments together. The various types of LC that have been used with ICP-MS detection are discussed and advantages over traditional methods of detection are highlighted, such as the improvements in sensitivity and selectivity. Several applications that have been described in the literature are reviewed. An outlook for the future of LC-ICP-MS, particularly with regard to elemental speciation is given.

Chromatography, Liquid↗
PubMed1999

Divergent mechanisms for loss of Ah-responsiveness in benzo[a]pyrene- and adriamycinR-resistant MCF-7 cells.

The intracellular aryl hydrocarbon receptor (AhR) mediates signal transduction by environmental pollutants such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and benzo[a]pyrene by functioning as a ligand-activated transcription factor. We have investigated AhR signaling in sublines of the human breast cancer cell line MCF-7 selected for resistance to AdriamycinR (AdrR) and benzo[a]pyrene (BP(R)). Previously we reported that AdrR cells have a loss of estrogen receptor (ER) expression and are Ah-nonresponsive. Here we show that AhR mRNA and protein are expressed at normal levels in AdrR cells, and the activated AhR complex is functionally capable of binding a xenobiotic responsive element. In MCF-7 cells AhR was depleted to 15% of normal levels after 4 hr TCDD treatment; however, 45% of AhR remained in AdrR cells during this time course. In BP(R) cells AhR mRNA levels were found to be decreased relative to wild-type cells, which led to decreased AhR protein levels and DNA-binding activity. Cellular ER content has been shown to correlate with Ah-responsiveness in human breast cancer cell lines. BP(R) cells were found to be ER-positive, although chronic (BP(R) cells) and acute (24 hr) exposure to benzo[a]pyrene led to significantly lower ER protein levels in MCF-7 cells. We conclude that loss of Ah-responsiveness occurs by different mechanisms in xenobiotic-resistant MCF-7 sublines: AhR mRNA is down-regulated in BP(R) cells, whereas AdrR cells are deficient in AhR signaling by a mechanism unrelated to AhR expression and activity.

Antineoplastic Agents↗
PubMed1997

Inductively coupled plasma mass spectrometric detection for chromatography and capillary electrophoresis.

Inductively coupled plasma mass spectrometry (ICP-MS) is now a well established detection technique for liquid chromatography, gas chromatography, supercritical fluid chromatography and capillary electrophoresis. A review of the literature with particular regard to ICP-MS as a chromatographic and capillary electrophoretic detector is presented. The various modes of chromatography and capillary electrophoresis are discussed and practical descriptions for hyphenating the techniques with the ICP mass spectrometer are given. Sample introduction systems and data acquisition methods are reviewed along with the numerous applications of ICP-MS as a chromatographic detector. In addition, alternative plasma sources, such as the atmospheric and reduced pressure helium microwave-induced plasmas for chromatographic detection are described.

Chromatography, Gas↗
PubMed1997

Speciation of chromium dyes by high-performance liquid chromatography with inductively coupled plasma mass spectrometric detection.

High-performance liquid chromatography (HPLC) coupled to inductively coupled plasma mass spectrometry (ICP-MS) was employed for the separation and detection of chromium species in azo dyes, Acid blue 158 and Acid Blue 193; mainly Cr(III) and Cr(VI). The dyes were first analyzed for total metal content using ICP-MS and their stability in solution was studied by measuring their absorbance through a range of pH values. Then an isocratic chromatographic method employing reversed-phase liquid chromatography with mass spectrometric detection was developed. Applying this method to the separation of these dyes, the absolute detection limits of Acid Blue 158 and 193 were 1 and 5 ng respectively. Additionally, Acid Blue 158 did not contain any chromium species. On the other hand, Acid Blue 193 contained uncomplexed and potentially bioavailable Cr(III). Acid Blue 193 did not have any toxic Cr(VI) present in the samples.

Anions↗