Surveillance study of novobiocin and phenylbutazone residues in raw bovine milk using liquid chromatography-tandem mass spectrometry.

A simple method permitting the simultaneous determination of trace residues of novobiocin and phenylbutazone in raw milk samples using liquid chromatography-tandem mass spectrometry was developed. Raw milk samples were mixed with acetonitrile to facilitate the concurrent precipitation of milk proteins and extraction of both veterinary drugs. Without additional clean-up or concentration of the resulting extract, the analytes could be quantified at concentrations as low as 0.0025 and 0.001 microg ml(-1) for phenylbutazone and novobiocin, respectively. The analysis of a series of fortified raw milk samples at analyte concentrations ranging from 0.005 to 0.1 microg ml(-1) and from 0.01 to 0.2 microg ml(-1) for phenylbutazone and novobiocin, respectively, yielded average recoveries ranging from 89.2% to 104.3% with standard deviations below 7%. The analytical method was applied to the analysis of raw milk samples collected from transport trucks upon delivery at dairy-processing plants throughout Alberta, Canada. Novobiocin was detected in 13 of 1072 samples tested at concentrations ranging from 0.001 to 0.007 microg ml(-1). Phenylbutazone was not detected in any of the samples tested.

Large volume injection for the direct analysis of ionophores and avermectins in surface water by liquid chromatography-electrospray ionization tandem mass spectrometry.

A simple method for the direct determination of residues of ionophore antibiotics and avermectin antiparasitics in surface water is reported. Using a large volume injector, a mixture of methanol and surface water is injected into an analytical liquid chromatography (LC) column and subsequently screened for residues of these veterinary pharmaceuticals using electrospray ionization tandem mass spectrometry. On-line sample enrichment and chromatographic separation are achieved using a single, short (20mm) octadecylsilane LC column. The method permits the detection of four ionophores and two avermectins in surface water samples at low ng L(-1) concentrations. Minimal matrix effects were observed for a variety of surface water samples which permitted the use of reagent-based standards for quantitation.

Attempted suicide by ingestion of methoxychlor.

A rare case involving an attempt to commit suicide by ingestion of a commercially available product containing methoxychlor as the active ingredient is presented. Clinical symptoms exhibited by the patient included no response to stimuli, pale skin, and profuse sweating. A serum sample collected at the time of admission to the hospital was found to contain 0.67 microg/mL of methoxychlor. The determination of methoxychlor was performed using gas chromatography-mass spectrometry.

Use of solid phase extraction disks for the GC-MS analysis of acidic and neutral herbicides in drinking water.

An analytical procedure was developed in which thirteen herbicides (10 acidic and 3 neutral compounds) may be extracted from drinking water samples using solid phase extraction disks and subsequently analyzed by gas chromatography-mass spectrometry. Using 8 replicate samples consisting of reagent water fortified with nanogram quantities of each herbicide, the average percent recoveries and method detection limits were determined for each analyte. The method was found to be suitable for the determination of individual herbicides in drinking water at concentrations of approximately 10 ng/L.

Case study: fatal poisoning by malathion.

A case involving a fatal poisoning (suicide) by the insecticide malathion is described. The intact insecticide was found in the post-mortem blood and gastric contents at concentrations of 1.8 and 978 micrograms/ml, respectively. None of the insecticide was found in the autopsied liver tissue. Gas chromatography-mass spectrometry (GC-MS) techniques were used for the identification and quantification of malathion in the body fluids.

Elevated blood lead levels from exposure via a radiator workshop.

Elevated lead levels were discovered in blood samples collected from family members where both the father and the mother worked in a radiator repair workshop. The father and mother were found to have blood lead levels of 2.0 and 0.5 mumol/L (41.7 and 10.4 micrograms/dL), respectively. The father's blood lead level was just below the Canadian occupational health and safety intervention level (2.5 mumol/L or 52.1 micrograms/dL). The two children had blood lead levels of 1.0 and 0.8 mumol/L (20.8 and 16.7 micrograms/dL), both of which are in excess of the recommended guideline for intervention in the case of children (0.5 mumol/L or 10.4 micrograms/dL). The exposure of the two children was possibly due to a combination of pathways including exposure at the workshop itself during visits and also the transportation of lead-containing dust to the home environment.

Determination of copper, manganese and zinc in human liver.

Autopsied liver tissue samples collected from 42 males and 31 females were analyzed for copper, manganese and zinc using atomic absorption spectrometry (AAS). With the exception of two liver samples for which the copper levels were determined to be 74.8 and 104.0 micrograms/g (dry weight), hepatic copper concentrations were found to range from 1.7 to 32.4 micrograms/g with a mean concentration of 14.2 micrograms/g and standard deviation of 7.0 micrograms/g. Manganese concentrations (with the exception of one sample having 12.9 micrograms/g) ranged from 0.22 to 4.6 micrograms/g with a mean of 2.26 +/- 1.00 micrograms/g. Hepatic zinc levels averaged 118.3 +/- 44.4 micrograms/g and ranged from 38.5 to 231.3 micrograms/g. There were no apparent trends for the levels of any metals versus age nor were there any differences in average hepatic metal concentrations for males and females.

Apoptosis in renal cell carcinoma: detection by in situ end-labeling of fragmented DNA and correlation with other prognostic factors.

Because stage and grade of renal cell carcinoma (RCC) sometimes fail to predict the patient's outcome, additional prognostic predictors are needed. Apoptosis is a process of programmed cell death seen in both normal and neoplastic tissues, which has been shown to have prognostic significance in some tumor types. Forty-seven RCCs were studied for size, grade, stage, apoptosis, and proliferation. Fragmented DNA, a hallmark of apoptosis, was detected in situ by a process in which the fragmented DNA was labeled with a biotinylated nucleotide, which, in turn, was detected by an avidin-biotin-peroxidase labeling system. The proliferating tumor cells were detected by immunostaining with the MIB-1 antibody. The apoptotic index and proliferation index of each RCC were expressed as the number of tumor cells undergoing apoptosis and proliferation per 1,000 tumor cells. For grade I to IV RCCs, the median proliferative index was 13, 41, 119, and 143; the median apoptotic index was 8, 12, 39, and 73. For stage I to IV RCCs, the median proliferative index was 21, 34, 70, and 144; the median apoptotic index was 8, 9, 20, and 69. There was a statistically significant correlation of tumor grade, stage, and size with both proliferative index and apoptotic index. There was a statistically significant correlation between proliferation index and apoptotic index. In conclusion, apoptosis can be easily and reliably recognized by the in situ end labeling of fragmented DNA and may help predict the outcome of RCC.

Solid phase extraction of 2,4-D from human urine.

A method for determining urinary concentrations of 2,4-D in samples collected from non-occupationally, environmentally exposed individuals was developed. The 2,4-D was extracted from fortified human urine samples using octadecylsilane solid phase extraction cartridges. The average percent recovery for urine samples spiked at 2 and 20 ng/mL was 100% and 93%, respectively. The method detection limit was estimated to be 0.75 ng of 2,4-D per mL of urine based on a 10 mL sample size. The potential use of 2,4-dichlorophenylacetic acid as a surrogate standard was also investigated.

Normal values for pentachlorophenol in urine samples collected from a general population.

Aliquots of urine samples collected over a 24-h period from normal individuals were analyzed for pentachlorophenol (PCP). Urine samples were taken from subjects living in various regions (both rural and urban) throughout the province of Saskatchewan. Urinary PCP concentrations were determined with gas chromatography-mass spectrometry and stable isotope dilution. The normal PCP concentrations were found to range from 0.05 to 3.6 ng/mliters. Because the aliquots analyzed were taken from 24-h sample collections, the normal range of PCP excreted on a daily basis was determined. A total of 69 samples taken from 26 males and 43 females who ranged in age from 6 to 87 years were analyzed. The average amount of excreted PCP was determined to be 4.3 nmol/day.

Determination of pentachlorophenol in commercially prepared lyophilized human urine control samples.

Commercially available reference materials consisting of lyophilized human urine are routinely utilized by clinical chemists to monitor laboratory performance for a variety of analyses. In this study commercially prepared lyophilized human urine control samples were reconstituted and analyzed for pentachlorophenol. Based on replicate analyses of two different reference materials, the levels of PCP in each were found to be representative of the levels typically present in urine samples collected from the general population of the province of Saskatchewan.