Publications by authors named "Jamie Dunn"

Article Synopsis
  • Higher olefins (HO) are important chemicals used to make various products including plastics, lubricants, and detergents, and their developmental toxicity was studied for regulatory purposes.
  • Five specific HO were tested on pregnant Sprague-Dawley rats at different doses (0, 100, 300, and 1000 mg/kg bw/day) to assess their effects from Day 3 to Day 19 of gestation.
  • The studies found no significant maternal or fetal toxicity from HO, with a No-Observed-Adverse-Effect Level (NOAEL) of 1000 mg/kg bw/day, indicating safety for both mother and fetus at this dose.
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Higher olefins (HO) are a category of unsaturated hydrocarbons widely used in industry applications to make products essential for daily human life. Establishing safe exposure limits requires a solid data matrix that facilitates understanding of their toxicological profile. This in turn allows for data to be read across to other members of the category, which are structurally similar and have predictable physico-chemical properties.

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N-sulfonated oversulfated chondroitin sulfate (NS-OSCS), recently reported as a potential threat to the heparin supply, was prepared along with its intermediate derivatives. All compounds were spiked into marketplace heparin and subjected to United States Pharmacopeia (USP) identification assays for heparin (proton nuclear magnetic resonance [(1)H NMR], chromatographic identity, % galactosamine [%GalN], anti-factor IIa potency, and anti-factor Xa/IIa ratio). The U.

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A novel analogue of sibutramine, 11-desisobutyl-11-benzylsibutramine, has been discovered. During routine ion mobility spectrometry (IMS) screening of a weight loss supplement collected at an US FDA import operation facility an unknown peak was observed. Further analysis of the supplement by liquid chromatography-mass spectrometry (LC-MS) and high resolution mass spectrometry revealed an unknown peak with a relative retention time of 1.

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Ion mobility spectrometry was used as a rapid screening tool for the detection of acetildenafils, sildenafils and avanafil within adulterated herbal supplement matrices. Acetildenafils show a tendency for partial fragmentation during the desorption/ionization process affording two peaks in the ion mobility spectrum in addition to the intact compound. The fragmentation appears to occur α to the carbonyl group along the CN bond attaching the piperazine moiety, producing a common fragment (K₀=1.

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Ion mobility spectrometry (IMS) served as a rapid, qualitative screening tool for the analysis of adulterated weight-loss products. We have previously shown that sibutramine extracted into methanol from dietary supplements can be detected at low levels (2ng) using a portable IMS spectrometer, and have adapted a similar method for the analysis of additional weight-loss product adulterants. An FDA collaborative study helped to define the limits for fluoxetine with a limit of detection of 2ng.

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Unlabelled: Study Type - Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Guidance from the UK National Institute for Health and Clinical Excellence (NICE) on the use of intraoperative cell savage (ICS) has been in place for over 3 years and recommends its routine usage in all patients undergoing radical pelvic urological surgery. The current series describes the contribution of ICS to contemporary blood conservation strategies and the goal of 'bloodless' cystectomy.

Objective: •  To describe a 10-year experience of intra-operative cell salvage (ICS) during radical cystectomy at a regional cancer centre.

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In response to recent incidents of undeclared sibutramine, an appetite suppressant found in dietary supplements, we developed a method to detect sibutramine using hand-held ion mobility spectrometers with an analysis time of 15 s. Ion mobility spectrometry is a high-throughput and sensitive technique that has been used for illicit drug, explosive, volatile organic compound and chemical warfare detection. We evaluated a hand-held ion mobility spectrometer as a tool for the analysis of supplement extracts containing sibutramine.

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We previously published a strong-anion-exchange-high performance liquid chromatography (SAX-HPLC) method for the detection of the contaminant over sulfated chondroitin sulfate (OSCS) in heparin sodium active pharmaceutical ingredient (API). While APIs have been processed to remove impurities, crude heparins contain insoluble material, chondroitin sulfates, heparan sulfate, and proteins that may interfere with the recovery and measurement of OSCS. We examined 500MHz (1)H NMR, capillary electrophoresis (CE), and SAX-HPLC to quantify OSCS in crude heparin.

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Mass spectrometry is the tool of choice to investigate protein phosphorylation, which plays a vital role in cell regulation and diseases such as cancer. However, low abundances of phosphopeptides and low degrees of phosphorylation typically necessitate isolation and concentration of phosphopeptides prior to MS analysis. This review discusses the enrichment of phosphopeptides with immobilized metal affinity chromatography, reversible covalent binding, and metal oxide affinity chromatography.

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Determination of the age of a handwritten or ink printed questioned document can be an important consideration in forensic cases. Most often the age of a document is determined by the chemical behavior of the dyes that make up the ink. Exposure of the dyes to environmental factors such as oxygen and ultraviolet or visible light cause them to degrade.

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Matrix-assisted laser desorption/ionization plates coated with poly(2-hydroxyethyl methacrylate) (PHEMA) brushes that are derivatized with Fe(III)-nitrilotriacetate (NTA) complexes allow selective, efficient phosphopeptide enrichment prior to analysis by mass spectrometry (MS). Fe(III)-NTA-PHEMA brushes (60 nm thick) have a phosphopeptide binding capacity of 0.6 microg/cm(2) and exhibit phosphopeptide recoveries of over 70%, whereas much thinner polymer films containing Fe(III)-NTA afford a recovery of only 20%, and a monolayer of Fe(III)-NTA shows a recovery of just 10%.

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Laser desorption mass spectrometry (LDMS) is emerging as a technique for questioned document examination. Its use is limited to detecting ink dyes that are neutral or singly charged. Several inks contain dyes that are multiply charged and LDMS cannot be employed for their identification.

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Metal affinity complexes were chemically grafted onto the surface of gold matrix-assisted laser desorption/ionization (MALDI) plates by coupling a derivative of nitrilotriacetate (NTA) to immobilized poly(acrylic acid) (PAA) and subsequently forming the Fe(III)-NTA complex. The immobilized complexes can adsorb phosphorylated peptides preferentially from protein digests; deposition of digests on these surface-modified plates, followed by rinsing with an acetic acid solution, addition of matrix, and subsequent analysis by MALDI MS, resulted in mass spectra dominated by peaks corresponding to phosphopeptides. In the case of analyzing a tryptic digest of beta-casein, conventional MALDI MS revealed only one monophosphopeptide, while use of the Fe(III)-NTA-PAA-modified plate resulted in strong signals due to two additional tetraphosphorylated species.

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Photodegradation and laser desorption mass spectrometry (LDMS) is a powerful combination of methods capable of characterizing dyes found in pen inks. Rhodamine dyes in pens that contain red ink were analyzed directly from paper (no extraction step is necessary). Inks exposed to incandescent light form photodegradation products (compounds with lower molecular weights than that of the intact dye) and in some instances, photoproducts (compounds with higher molecular weights than that of the intact dye).

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