Is your technetium generator eluate sterile?
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OBJECTIVE: This study was performed to assess the sterility of multidose 99mTc generator eluate vials at the end of a working day. METHODS: Expired 99mTc generator eluate vials were collected over a period of 10 wk and stored until the activity reached background. Four batches of 10 vials each were selected randomly and sent to an independent microbiology laboratory for sterility testing. RESULTS: No eluate showed any microbial growth after 14 d incubation in growth media. CONCLUSION: Retrospective sterility testing of 99mTc generator eluate confirmed the validity of our departmental protocol for radiopharmaceutical preparation. Sterility testing has become part of our quality control program. (+info)
Specific binding of ethanol to cholesterol in organic solvents.
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Although ethanol has been reported to affect cholesterol homeostasis in biological membranes, the molecular mechanism of action is unknown. Here, nuclear magnetic resonance (NMR) spectroscopic techniques have been used to investigate possible direct interactions between ethanol and cholesterol in various low dielectric solvents (acetone, methanol, isopropanol, DMF, DMSO, chloroform, and CCl(4)). Measurement of (13)C chemical shifts, spin-lattice and multiplet relaxation times, as well as self-diffusion coefficients, indicates that ethanol interacts weakly, yet specifically, with the HC-OH moiety and the two flanking methylenes in the cyclohexanol ring of cholesterol. This interaction is most strong in the least polar-solvent carbon tetrachloride where the ethanol-cholesterol equilibrium dissociation constant is estimated to be 2 x 10(-3) M. (13)C-NMR spin-lattice relaxation studies allow insight into the geometry of this complex, which is best modeled with the methyl group of ethanol sandwiched between the two methylenes in the cyclohexanol ring and the hydroxyl group of ethanol hydrogen bonded to the hydroxyl group of cholesterol. (+info)
Measurement of apolipoprotein B concentration in plasma lipoproteins by combining selective precipitation and mass spectrometry.
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The measurement of apolipoprotein B (apoB) in purified lipoproteins by immunological assays is subject to criticism because of denatured epitopes or immunoreactivity differences between purified lipoproteins and standard. Chemical methods have therefore been developed, such as the selective precipitation of apoB followed by quantification of the precipitate. In this study, we present the measurement of apoB concentration in lipoproteins purified by ultracentrifugation by combining isopropanol precipitation and gas chromatography/mass spectrometry. Very low density lipoprotein (VLDL; d < 1.006 g/mL); VLDL plus intermediate density lipoprotein (VLDL + IDL; d < 1.019 g/mL); and VLDL, IDL, and low density lipoprotein (VLDL + IDL + LDL; d < 1.063 g/mL) were purified by ultracentrifugation. Apolipoprotein B-100 was selectively precipitated by isopropanol. The leucine content of the pellet was then determined by gas chromatography/mass spectrometry, using norleucine as internal standard. Knowledge of the number of leucine molecules in one apoB-100 molecule makes it possible to calculate the plasma concentration of apoB in the various lipoprotein fractions. ApoB in IDL (d 1.006-1.019 g/mL) and LDL (d 1.019-1.063 g/mL) were then determined by subtracting VLDL-apoB from apoB in lipoproteins d < 1.019 and apoB in lipoproteins d < 1.019 g/mL from apoB in lipoproteins d < 1.063 g/mL, respectively. The isopropanol precipitate was verified as pure apoB (>97%) in lipoprotein fractions isolated from normo- and hyperlipidemic plasma and the method appeared reproducible. The combination of isopropanol precipitation and the GC/MS method appears therefore to be a precise and reliable method for kinetic and epidemiological studies. (+info)
Simultaneous detection and quantitation of diethylene glycol, ethylene glycol, and the toxic alcohols in serum using capillary column gas chromatography.
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Determination of toxic glycols and alcohols in an emergency setting requires a rapid yet accurate and reliable method. To simultaneously determine diethylene glycol (DEG) along with ethylene glycol, methanol, isopropanol, acetone, and ethanol, we modified a previously developed gas chromatographic (GC) method. The system used a Hewlett-Packard 6890 GC with EPC, a Gooseneck splitless liner, and an Rtx-200 capillary column (30 m x 0.53-mm i.d., 3 mm). After serum samples were deproteinized using ultrafiltration (Millipore Ultrafree-MC), 1 mL of the protein-free filtrate was manually injected into the GC. Internal standards for alcohols (and acetone) and glycols were n-propanol and 1,3-butanediol, respectively. All compounds eluted within 3.5 min (linear temperature gradient from 40 to 260 degrees C); total run time was 6.5 min. Limit of detection and linear range for all compounds were 1 or 2.5 mg/dL and 0-500 mg/dL, respectively. In addition, there was no interference from propionic acid, propylene glycol, and 2,3-butanediol. The modifications in the equipment and temperature program allowed increased resolution and thus, detection and reliable quantitation of DEG and other common toxic glycols and alcohols of clinical interest. (+info)
A fatality due to accidental PineSol ingestion.
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The case history and toxicological findings of a fatal PineSol intoxication are presented. An 89-year-old white female with Alzheimer's disease accidentally drank PineSol and was subsequently brought to the hospital where she was pronounced dead on arrival. Significant autopsy findings included acute erosive gastritis. There appeared to be no aspiration of PineSol into the lungs. Isopropanol along with 1-alpha-terpineol are the two major toxic ingredients of PineSol. The toxicological screening and quantitiation of 1-alpha-terpineol in postmortem fluids was performed by gas chromatography-mass spectrometry using a simple one-step extraction. Postmortem blood, urine, and gastric levels of 1-alpha-terpineol were 11.2 mg/L, 5.76 mg/L, and 15.3 g/L, respectively. Postmortem blood, vitreous humor, urine, and gastric acetone concentrations were 25, 31, 33, and 28 mg/dL. Postmortem concentrations of isopropanol were less than 10 mg/dL in the blood, vitreous humor, urine, and gastric contents. The cause of death was ruled acute 1-alpha-terpineol intoxication due to accidental ingestion of PineSol, presumably caused by confusion related to Alzheimer's disease. (+info)
Inhibition of human peripheral blood neutrophil respiratory burst by alcohol-based venipuncture site disinfection.
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Ethanol inhibits the respiratory burst of neutrophils. Therefore, the effects of alcohol-based skin disinfection on oxygen metabolism in neutrophils were tested using 70% ethanol or an ethanol-isopropanol-n-propanol mixture. Neutrophil respiratory burst activity as assessed fluorometrically by oxidation of 2', 7'-dichlorofluorescein diacetate increased at 10 min after disinfection with 70% ethanol compared to the activity at 30 s. The increase was significant for triggering oxidative burst with formyl-peptide but not with phorbol myristate acetate. (+info)
Effects of i-propanol on the structural dynamics of Thermomyces lanuginosa lipase revealed by tryptophan fluorescence.
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Influence of isopropanol (iPrOH) on the structural dynamics of Thermomyces lanuginosa lipase (TLL) was studied by steady-state, time-resolved, and stopped-flow fluorescence spectroscopy, monitoring the intrinsic emission of Trp residues. The fluorescence of the four Trps of the wild-type enzyme report on the global changes of the whole lipase molecule. To monitor the conformational changes in the so-called "lid," an alpha-helical surface loop, the single Trp mutant W89m (W117F, W221H, W260H) was employed. Circular dichroism (CD) spectra revealed that iPrOH does not cause major alterations in the secondary structures of the wild-type TLL and W89m. With increasing [iPrOH], judged by the ratio of emission intensities at 350 nm and 330 nm, the average microenvironment of the Trps in the wild-type TLL became more hydrophobic, whereas Trp89 of W89m moved into a more hydrophilic microenvironment. Time-resolved fluorescence measurements revealed no major changes to be induced by iPrOH neither in the shorter fluorescence lifetime component (tau(1) = 0.5--1.2 ns) for the wild-type TLL nor in the longer fluorescence lifetime component (tau(2) = 4.8--6.0 ns) in the wild-type TLL and the W89m mutant. Instead, for W89m on increasing iPrOH from 25% to 50% the value for tau(1) increased significantly, from 0.43 to 1.5 ns. The shorter correlation time phi(1) of W89m had a minimum of 0.08 ns in 25% iPrOH. Judged from the residual anisotropy r(infinity) the amplitude of the local motion of Trp89 increased upon increasing [iPrOH] 10%. Stopped-flow fluorescence spectroscopy measurements suggested the lid to open within approximately 2 ms upon transfer of W89m into 25% iPrOH. Steady-state anisotropies and longer correlation times revealed increasing concentrations of iPrOH to result also in the formation of dimers as well as possibly also higher oligomers by TLL. (+info)
Development of a physiologically based pharmacokinetic model of isopropanol and its metabolite acetone.
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A physiologically based pharmacokinetic (PBPK) model for isopropanol (IPA) and its major metabolite, acetone, is described. The structure of the parent chemical model, which can be used for either IPA or acetone by choosing the appropriate chemical-specific parameters, is similar to previously published models of volatile organic chemicals such as styrene. However, in order to properly simulate data on the exhalation of IPA and acetone during inhalation exposures, it was necessary to expand the description of the lung compartment to include a subcompartment for the upper respiratory tract mucus layer. This elaboration is consistent with published PBPK models of other water-soluble vapors in which the mucus layer serves to absorb the chemical during inhalation and then release it during exhalation. In the case of IPA exposure, a similar PBPK structure is used to describe the kinetics of the acetone produced from the metabolism of IPA. The resulting model is able to provide a coherent description of IPA and acetone kinetics in the rat and human for exposures to IPA by several routes: intravenous, intraperitoneal, oral, inhalation, and dermal. It is also able to consistently reproduce kinetic data for exposures of rats or humans to acetone. Thus, the model provides a validated framework for performing chemical-specific route-to-route extrapolation and cross-species dosimetry, which can be used in place of generic default calculations in support of risk assessments for IPA and acetone. (+info)