Forensic analysis of soman exposure using characteristic fragment ions from protein adducts

The verification of exposure to nerve agents is a serious challenge, especially in cases of soman (GD) poisoning. Protein adducts are reliable biomarkers, that provide forensic information and evidence during incidents of terrorism or sporadic poisoning. Mass spectrometry, coupled with a proteomics approach, was established for the forensic analysis of GD-based protein adducts. The fragmentation pathways of GD-based protein adducts were investigated for the first time using electrospray ionization tandem mass spectrometry. Three abundant natural loss product ions, [M+2H-54]²⁺ (loss of two carbon cations), [M+2H-72]²⁺ (loss of tert-butyl and methyl moieties), and [M+2H-84]²⁺ (loss of the pinacolyl moieties), were observed in each of the GD-labeled adducts, and the product ions were independent of protein structure and exposure route. A unique mechanism for the formation of product ions involving GD-protein adducts is proposed here. These findings support the development of a simple and precise forensic analysis technique to rapidly verify GD poisoning using these three GD-related product ions.

[The expression of transcription factors Snail and Slug in epithelial-mesenchymal transition of human lens epithelial cells induced by transforming growth factor-β2]

OBJECTIVE

To investigate the expression of transcription factors snail and slug in epithelial mesenchymal transition (EMT) of human lens epithelial cells (HLEC) induced by transforming growth factor-β2 (TGF-β2).

METHODS

Experimental research. HLEC were treated with different concentrations of TGF-β2 (1.0 and 10.0 μg/L) for different time. The morphological changes were observed under inverted microscope. The expression and cellular localization of snail and slug were evaluated by immunofluorescence. Expressions of snail, slug, E-Cadherin and α-SMA were further determined by Western blot analysis. Single factor analysis of variance, rank sum test and Pearson correlation were used for statistical analysis.

RESULTS

Cultured HLEC were polygonal monolayer cells with tight intercellular adhesion closely and patchy distribution. After treatment of different doses of TGF-β2 for 24 h, HLEC became isolated, exhibited long spindle-like shape as fibroblastic phenotype. The immunofluorescence staining indicated that snail and slug were localized in the nuclei. The expressions of snail and slug appeared to be positive correlative to TGF-β2 dose (snail protein expression: 0.74±0.16, 1.13±0.03, 1.54±0.18 and slug protein expression: 1.96±0.02, 3.12±0.09, 4.07±0.12 in HLEC treated with 0.1, 1.0 and 10 μg/L TGF-β2 respectively) (χ(2)=9.62,P=0.022;F=241.10,P<0.01). In addition, the expression of α-SMA and E-Cadherin showed the similar form (α-SMA protein expression: 0.87±0.04, 1.42±0.11, 2.17±0.36 and E-Cadherin protein expression: 2.50±0.36, 1.65±0.32, 0.41±0.14 in HLEC treated with 0.1, 1.0 and 10.0 μg/L TGF-β2 respectively) (χ(2)=9.97,P=0.019;F=19.99,P<0.01). All Pearson correlation coefficient were close to 1. The expression of snail and slug in HLEC were also increased with extending duration of TGF-β2 (1.0 μg/L). The expression levels of both proteins were modestly up-regulated at 8 hours, robustly increased at 24 h, reached peak at 48h and began to decline at 72 h (snail protein expression: 0.90±0.13, 1.43±0.14, 1.96±0.27, 1.57±0.16 and slug protein expression: 0.91±0.36, 1.24±0.16, 2.44±0.26, 1.43±0.16 in HLEC treated with 1.0 μg/L TGF-β2 for 8 h, 24 h, 48 h and 72 h respectively) (F=12.49,P=0.001;F=14.03,P<0.01).

CONCLUSION

Transcription factors snail and slug might be time and dose-dependently involved in in-vitro TGF-β2-induced EMT of HLEC. (Chin J Ophthalmol, 2016, 52: 285-290).

Neurobehavioral study of prenatal exposure to hyperthermia combined with irradiation in mice

Thirty-two pregnant adult LACA mice were randomly assigned to one of five exposure groups: control, 38 degrees C, 42 degrees C, irradiation, and 42 degrees C + irradiation. Animals were exposed on gestation day 9 to either 38 degrees C waterbath for 5 min, 42 degrees C waterbath for 5 min, treatment with 0.5 Gy of 60Co gamma irradiation, or pretreatment at 42 degrees C waterbath for 5 min following by 0.5 Gy of 60CO gamma irradiation. On postnatal day 7, litters were reduced to a maximum of eight pups per litter, with equal members of male and female offspring whenever possible. A total of 216 pups were observed for the age of acquisition of four physiological landmarks (pinna detachment, incisor eruption, eye opening, testes descent), six developmental reflexes (surface righting, cliff avoidance, auditory startle, air righting, visual placing, hindlimb splaying), and examination of learning and memory function. These studies, at threshold exposure levels to hyperthermia and ionizing radiation, indicate there is no consistent significant additional postnatal effect when pregnant mice are exposed to both of these agents. These studies are important for our understanding of the relative long-range effects of prenatal exposure to hyperthermia and acute dose irradiation early in gestation on neurobehavioral teratogenesis.