Improving the Sensitivity of FAB Tandem Mass Spectrometry for PAH-DNA Adducts

Abstract

The mass spectrometric detection limits for guanine, adenine, and an adeninddimethylbenthracene adduct were greatly improved by converting the materials to pentafluorobenzyl derivatives, as well as by doing coaxial continuous flow-FAB (coaxial cf-Fast Atom Bombardment). The lowest detection limit (approximately 10 pg) was achieved when the derivatized sample was introduced by coaxial cf-FAB and the determination was by fill-scan mass spectrometry. The lowest detection limit achieved by tandem mass spectrometry was 50 pg obtained after derivatization, coaxial cf-FAB introduction and detection with an extended mass range array.     

Testing of aseptic machines for efficiency of sterilization of packaging materials by means of hydrogen peroxide

Aseptic packaging machinery fills heat sterilized foods into sterilised packaging under aseptic conditions. One of the main components of the aseptic machinery is the means of sterilizing the packaging material and the efficiency of this is of paramount importance. A method of measuring this efficiency using Bacillus subtilis SA22 is described and evaluated.     

The internship marketplace: The new depression?

Conducted a survey to provide data on past and future estimates of supply and demand in the internship marketplace and on current and anticipated financial support for clinical psychology graduate students and interns. A questionnaire sent to training directors of the 149 listed clinical psychology graduate programs and 242 listed predoctoral clinical internship facilities, yielded returns of 67% and 81% respectively. Results show a greater increase in demand than in supply of internship positions for the past 5 yrs, with a 14% nonplacement rate predicted within 3 yrs. Financial support data predict shifting of sources of funding from current levels such that a nonsupport rate of 12% for graduate students and 9% for interns is expected. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sokoloviana kucheruki sp. n. from the killdeer from Cuba (Analgoidea, Pterolichidae)

Wistar rats consumed a liquid diet containing sustagen and ethanol for a period of 150 days. Control animals were pair-fed an identical diet except for isocaloric substitution of sucrose for ethanol. Forty-five days after the liquid diets were discontinued both groups were tested for performance on the Hebb-Williams maze. The experimental group made significantly more errors than the control group indicating that long-term ingestion of alcohol can lead to substantial impairment of problem-solving abilities in rats.     

Effect of salt and sucrose addition on the formation of the Amadori compound from methionine and glucose at 40 °C

Four model solutions with the Maillard precursors methionine and glucose were reacted at 40 °C for up to 15 days. The solutions had a high or low precursor concentration leading to either high or medium water activity (0.96; 0.86). The water activity of the two other solutions was reduced by adding either salt or sucrose. Glucose, methionine and the Amadori compound (Fru–Met) were quantified after 1, 2, 6, 10 and 15 days. The results show that high salt and sucrose levels had a much more pronounced influence on glucose consumption and Fru–Met formation than differences in water activity. Glucose degradation and Fru–Met formation was favoured by high sucrose levels and inhibited by high NaCl levels.     

Affinity of vitamin E analogues for the ubiquinone complex II site correlates with their toxicity to cancer cells

Scope: Vitamin E (VE) analogues, epitomised by the prototypic α‐tocopheryl succinate (α‐TOS), are potent anti‐cancer agents. α‐TOS has recently been shown to trigger apoptosis by targeting the ubiquinone (UbQ) binding site(s) of the mitochondrial complex II (CII) and to cause excessive production of reactive oxygen species. Methods and results: We have modelled, using two approaches, a range of VE analogues into the proximal UbQ (Q_p) binding site of CII. This study reveals that in both cases, the calculated interaction energies of individual VE analogues correlate (R² value >0.8) with their toxicity to cancer cells. Conclusion: These data further support the UbQ site(s) of CII as an important target determining the anti‐cancer activity of VE analogues as well as other emerging anti‐cancer drugs.