Use of fipronil {5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-trifluoromethyl)sulfinyl]-1H-pyrazole-3-carbonitrile CAS 120068-37-3} topical pet products on dogs and cats introduces low level residues into residences. Distribution and fate studies of fipronil on pets and in residences were performed to evaluate potential determinants of human exposure. Fipronil, desulfinyl fipronil, fipronil sulfone and fipronil sulfide were measured on hair clippings and brushed hair. The derivatives usually represented <10% of fipronil applied. Cotton gloves worn over impervious nitrile gloves, cotton cloths placed indoors in locations frequented by pets, and cotton socks worn by residents as direct dosimeters collected fipronil and its derivatives listed above in low amounts during 4-week study periods. Subsequent acid hydrolysis urine biomonitoring did not reveal significant excretion of biomarkers at ppb levels. The human exposure potential of fipronil is low relative to levels of health concern.

Uncaria rhynchophylla (Miq.) Miq. ex Havil is widely used in the treatment of hypertension. The Uncaria extract and its bioactives, rhynchophylline and isorhynchophylline, reduced the blood pressure and fatty content in liver cells. In the present study, the antihypertensive effects of Uncaria ethanol extract (UET), rhynchophylline (RT) and isorhynchophylline (IT) were investigated in spontaneously hypertensive rats (SHR) using UPLC-Q-Orbitrap/MS based lipidomics approach. Histological changes in the liver were evaluated. Cytolysis and fatty degeneration in the liver tissues were observed in the SHR group. Lipid species in WKY, SHR treated with UET, RT, and IT were plotted to obtain the Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) score plots. Fifty-six endogenous metabolites in the liver such as glycerides, glycerophospholipids, unsaturated fatty acids, and sphingomyelins were selected as potential hypertension associated biomarkers. In order to further explore the metabolite targets of UET for antihypertensive, student's t test and correlation analysis were performed to recognize the pattern recognition and to select the significant metabolites. Similar and prolonged reduction in blood pressure was observed in all SHR groups treated with UET, RT, and IT, while the metabolite profiles were perturbed slightly compared to that of the untreated SHR. Further analysis showed that only a few common components were observed in both RT and IT, which showed similar antihypertensive effect in spite of the distinct metabolic pathways. These results help in understanding the mechanisms of isomeric ingredients in exhibiting the antihypertensive effect but with different targets.

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DDT metabolism in humans yields DDA as the principal urinary metabolite and potential exposure biomarker. A method for DDA analysis in human urine was developed using pentafluorobenzyl bromide and diisopropylethyl amine. Dried hexane extracts were reacted for 1 hour at room temperature. The stable DDA-pentafluorobenzyl-ester derivative was analyzed by gas chromatography-electron capture detector (GC-ECD) and confirmed by gas chromatography-mass spectrometry (GC-MS) in selective ion monitoring mode. The limit of detection for DDA was 0.1 microg/L urine by GC-ECD and 2 microg/L urine by GC-MS, with a relative standard deviation of 12%. Urine specimens from DDT applicators in Swaziland and South Africa were analyzed to evaluate the method. The mean DDA levels during the spray season and post season were 59 and 11 microg/L, respectively. These results must be interpreted cautiously because different groups of workers provided urine specimens in each case. The DDA urinalysis may be a feasible monitoring strategy for low-level occupational and residential DDT exposure assessment in antimalaria campaigns.

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