Cynthia Lee Eddy

Hyaline droplet nephropathy resulting from exposure to 3,5,5-trimethylhexanoyloxybenzene sulfonate

Acute oral dosing of 3,5,5-trimethylhexanoyloxybenzene sulfonate (THBS) to adult male and female rats causes a male rat-specific nephrotoxicity manifested as exacerbation of hyaline droplet formation. This chemical is structurally distinct from the volatile hydrocarbons known to cause male rat-specific kidney lesions. Therefore, to classify THBS as a hyaline droplet-inducing agent, experiments were conducted to determine whether [14C]THBS equivalents bound to alpha 2 mu-globulin and caused the protein to accumulate in male rat kidney cortex. Two-dimensional gel electrophoretic separation of male rat kidney proteins indicated that alpha 2u-globulin levels in kidney increased 24 hr after a single oral dose of THBS (500 mg/kg). Furthermore, a sex-dependent retention THBS was noted as there was approximately 10 times more THBS equivalents in male rat kidney than in female rat kidney. Equilibrium dialysis experiments indicated that 40% of THBS equivalents bound reversibly to male rat kidney proteins, whereas no interaction between THBS and female rat kidney proteins was detected. Specific binding of THBS to alpha 2mu-globulin was determined by anion-exchange HPLC after which metabolites in the alpha 2u-globulin fraction were identified by gas chromatography with parallel radioactivity-mass spectrometry and mass spectrometry-matrix isolation Fourier-transform infrared analysis. Four metabolites of THBS were found in this protein fraction, and the major component (approximately 70%) was identified as the cis gamma-lactone of 3,5,5-trimethylhexanoic acid. Experiments were also conducted in mice to determine whether THBS bound to any mouse kidney proteins, particularly mouse urinary protein. The results indicated that there was no interaction between THBS and mouse urinary protein, a protein which shares significant homology with alpha 2u-globulin. These results indicate that THBS treatment exacerbates hyaline droplet formation in male rat kidneys by binding to alpha 2mu-globulin, thereby causing the protein to accumulate in the renal cortex. The interaction between THBS and alpha 2mu-globulin appears to be unique to this male rat-specific protein as THBS does not interact with a very similar protein found in mice.

Automated quartz injector/trap for fused-silica capillary columns

Abstract An automated quartz injector/trap was developed for a Perkin-Elmer 3920 gas chromatograph. The injector/trap serves to concentrate gaseous or liquid samples without introducing organic contaminants. The concentrated sample is volatilized and transferred to a second trap by cooling a small section of a fused-silica capillary column. Reconcentration in the capillary column preserves band-shape and provides a system which delivers quantitative results on a variety of samples. Liquid samples show relatives standard deviations of 1% and 2%, respectively, for isothermal and temperaure-programmed analyses. A detection limit of less than 1 ppb is expected, with a flame ionization detector, for samples of n-octane in air.

Improved radioactivity detector for fused-silica capillary columns

Abstract 14 C-labeled and unlabeled organic compounds eluting from fused-silica capillary columns were detected by the parallel combination of a radioactivity detector (RAD) and a flame ionization detector (FID). The RAD consists of a small-volume counter tube and ancillary electronics. It is constructed from readily available parts. For maximum signal-to-noise ratio, the RAD is operated at 70% counting efficiency. The resulting background is less than 5 cpm. The instrumentation delivers high chromatographic efficiency and eliminates combustion artifacts. Radioactive peaks are 12 sec wide, while the detection limit is ca. 440 cpm (0.2 nCi) for peaks with k ′ ⩽ 5. No degradation in column performance is apparent in the FID trace.

Identification of compounds responsible for an off-odor in wet polyacrylate superabsorbent polymers

Abstract Using dynamic headspace, GC–sniff-port coupled to mass spectrometry (MS) and Fourier transform IR [1] , and two-dimensional GC–MS–matrix isolation Fourier transform IR [2] , we identified the compounds responsible for an off-odor associated with the use of superabsorbent polymers (SAPs) in consumer products. Of those compounds, a C 7 vinyl ketone (5-methylhex-1-en-3-one, isobutyl vinyl ketone) was the best predictor of consumer reaction to the odor. After synthesis, we confirmed this compound as the most offensive odorant in the SAPs. Removing vinyl ketones from the monomer raw material effectively eliminated the product off-odor.

Modification of a commercial pyrolysis probe to improve its temporal and spatial temperature profiles: Performance evaluation using model polymers

Abstract A coiled-filament probe of a commercially available pyrolyzer (Chemical Data Systems, CDS Pyroprobe 120) was modified to change the temporal and spatial temperature profiles delivered by the probe. The modification changes the geometry of the heating filament: it is coiled tightly and a light coating of a ceramic cement is applied to maintain its dimensional stability while minimizing the possibility of developing an electrical short. The modified pyroprobe produced a reproducible and uniform temperature profile over a ∼3-mm long pyrolysis region and had near-perfect emissivity (∼0.95) for monitoring temperature with an optical thermometer. To conduct experiments off-line we also designed a glass housing for the tightly-coiled pyroprobe (TC-pyp). The housing has provisions for making a gas-tight seal with the pyroprobe, for introducing a gas to control the pyrolysis atmosphere and provide a rapid sweep of the pyrolysis region and for interfacing with a pre-trap to collect pyrolysates. To evaluate the results obtained with the TC-pyp we compared mass and temperature dependencies of Kraton D1107P pyrograms with those generated by a Pt ribbon-pyroprobe (PtR-pyp) and an unmodified coil pyroprobe. In addition, we report on the use of the instrumentation for quantitative analyses of model polymers.

Design of a gas chromatograph with parallel radioactivity and mass spectrometric detection: Application to the identification of the major metabolite of d-limonene associated with α2u-globulin

A Perkin Elmer 3920 gas chromatograph, equipped with a versatile inlet system (i.e. an injector/trap), was interfaced to a radioactivity detector and a mass-selective detector (H/P 5970B) to identify 14C-labeled compounds. The use of a pre-trap as a demountable, programmable-temperature injector, in conjunction with the injector/trap, allowed the introduction of 0.5-ml samples of rat kidney cytosol extracts to 0.32 mm I.D. capillary columns. The instrumentation greatly facilitated the identification of the major radiolabeled metabolite of d-limonene associated with the male rat-specific protein alpha 2u-globulin as 1,2-cis-d-limonene oxide.