Polycyclic aromatic hydrocarbon residues in serum samples of autopsied individuals from Tennessee.

This study reports the concentrations of polycyclic aromatic hydrocarbons (PAHs) in human blood sera samples (n = 650) obtained at autopsy from individuals who died of drug abuse, alcohol toxicity, homicide, suicide and other unknown causes. The analyzed samples from decedents revealed the presence of PAHs of which B(a)P was the most predominant one, followed by benzo(b)fluoranthene and benzo(k)fluoranthene. The other PAHs detected sporadically and measured were benzo(g,h,i)perylene, acenaphthene, anthracene, phenanthrene, and fluoranthene The mean concentrations of PAHs were greater in the twenties to fifties age groups compared to others. The PAH residue levels detected were high in African Americans compared to Caucasians, Asians, and Hispanics. It appears that environmental exposure, dietary intake and in some cases occupational exposure may have contributed to the PAH body burden. While the PAH residue concentrations measured fall within the range of those reported for healthy adults elsewhere, in isolated cases, the concentrations detected were high, calling the need for a reduction in PAH emissions and human biomonitoring studies for purposes of risk assessment.

Cyclophilin A is required for CXCR4-mediated nuclear export of heterogeneous nuclear ribonucleoprotein A2, activation and nuclear translocation of ERK1/2, and chemotactic cell migration.

The chemokine receptor CXCR4-mediated signaling cascades play an important role in cell proliferation and migration, but the underlying mechanisms by which the receptor signaling is regulated remain incompletely understood. Here, we demonstrate that CXCR4 was co-immunoprecipitated with cyclophilin A (CyPA) from the lysate of HEK293 cells stably expressing CXCR4. Although both the glutathione S-transferase-CXCR4 N- and C-terminal fusion proteins were associated with the purified CyPA, truncation of the C-terminal domain of CXCR4 robustly inhibited the receptor co-immunoprecipitation with CyPA in intact cells, thereby suggesting a critical role of the receptor C terminus in this interaction. Ligand stimulation of CXCR4 induced CyPA phosphorylation and nuclear translocation, both of which were inhibited by truncation of the C-terminal domain of CXCR4. CyPA was associated with transportin 1, and knockdown of transportin 1 by RNA interference (RNAi) blocked CXCL12-induced nuclear translocation of CyPA, thereby suggesting a transportin 1-mediated nuclear import of CyPA. CyPA formed a complex with heterogeneous nuclear ribonucleoprotein (hnRNP) A2, which underwent nuclear export in response to activation of CXCR4. Interestingly, the CXCR4-mediated nuclear export of hnRNP A2 was blocked by RNAi of CyPA. Moreover, CXCR4-evoked activation of extracellular signal-regulated kinase 1/2 (ERK1/2) was attenuated by CyPA RNAi, by overexpression of a PPIase-deficient mutant of CyPA (CyPA-R55A), and by pretreatment of the immunosuppressive drugs, cyclosporine A and sanglifehrin A. Finally, CXCL12-induced chemotaxis of HEK293 cells stably expressing CXCR4 or Jurkat T cells was inhibited by CyPA RNAi or CsA treatment.

Reduction in extracellular superoxide dismutase activity in African-American patients with hypertension.

Superoxide anions react with nitric oxide to form peroxynitrite and hence reduce the bioavailability of nitric oxide in the arteries. Extracellular superoxide dismutase (EC-SOD) is a major superoxide scavenger in human plasma and vascular tissues. The objective of this study is to assess whether essential hypertension is associated with an alteration in EC-SOD activity. In this report, blood samples were obtained from hypertensive (n=39) and normotensive (n=37) African-Americans. Plasma EC-SOD activity was measured using in-gel activity staining and spectrophotometric assays, EC-SOD protein level was measured using Western blotting, nitrotyrosine was measured using slot blotting, 8-isoprostane was measured with an enzyme immunoassay, and plasma copper and zinc concentrations were measured using an atomic absorption assay. Our data demonstrate that the copper, zinc, and plasma EC-SOD protein concentrations in the hypertensive and normotensive subjects are indistinguishable. Compared to normotensive controls, hypertensive patients have significantly reduced plasma EC-SOD activity. Plasma nitrotyrosine and 8-isoprostane levels are significantly higher in the hypertensive patients than in normotensive controls. Results from this study suggest that a reduction in EC-SOD activity in hypertensive patients is not due to a down-regulation of the SOD3 gene (encoding EC-SOD) or deficiency in mineral cofactors. Furthermore, the reduced EC-SOD activity might be at least partially responsible for the increased oxidative stress, as reflected by increased plasma nitrotyrosine and 8-isoprostane, in hypertensive subjects.

Disruption of testicular steroidogenesis and epididymal function by inhaled benzo(a)pyrene.

The objective of this study was to evaluate the effect of sub-acute exposure to inhaled benzo(a)pyrene (BaP) on testicular steroidogenesis and epididymal function in Fisher 344 rats. Animals were assigned randomly to two control groups and one experimental group for each exposure regimen. Treatment consisted of sub-acute exposure of rats via inhalation to 25, 75, and 100 microg BaP/m(3), 4 h daily for 10 days. Control animals were either exposed to carbon black (CB; sham) to control for inert BaP carrier or they remained unexposed (UNC). Blood samples were collected immediately after the cessation of exposures (time 0) and at 24, 48, and 72 h post-cessation of exposure, to assess the effect of bioavailable BaP on systemic testosterone and luteinizing hormone (LH) concentrations by radioimmunoassay (RIA). Progressive sperm motility of stored sperm (cauda epididymal sperm) was determined microscopically, while density of stored sperm was determined by hemocytometric counting. Progressive motility of stored sperm was reduced in rats exposed to 75 and 100 microg BaP/m(3) compared with their counterparts that were exposed to 25 microg BaP/m(3) or controls. Plasma testosterone concentrations declined as a result of exposure of rats to 75 microg BaP/m(3) from 0 to 48 h post-termination of exposure compared with controls (P<0.05; treatment x time interaction). This decrease was followed subsequently by a compensatory increase in the plasma concentrations of this steroid at 72 h post-cessation of exposures compared with previous time periods and controls (P<0.05). Increases in the mean plasma LH concentrations were observed in rats exposed to 75 microg BaP/m(3) compared with controls, throughout the time periods studied (P<0.05; treatment x time interaction). These data suggest that sub-acute exposure to inhaled BaP contributes to reduced testosterone concentrations and consequently impaired epididymal function of exposed animals.

Alteration of pregnancy related hormones and fetal survival in F-344 rats exposed by inhalation to benzo(a)pyrene.

The objective of this study was to evaluate the effect of subacute exposure to inhaled benzo(a)pyrene (BaP) on fetal survival and luteal maintenance using timed-pregnant Fisher 344 rats. Prior to assignment of pregnant rats to treatment and control groups, numbers of implantation sites were determined on gestation day (GD) 8 via midventral laparotomy. Subsequently, animals were assigned randomly to three treatment groups and two control groups. Treatment consisted of subacute exposure of rats via inhalation to BaP 25, 75, and 100 micro g/m(3), 4h daily for 10 days (GD-11-20). Control animals were either sham exposed to carbon black (CB) to control for inert BaP carrier or remained unexposed (UNC). Blood samples were collected on days 15 and 17 of gestation via sinus orbital veini-puncture for plasma. Number of pups per litter was determined postpartum and fetal survival rate was expressed as a percentage of the corresponding implantation sites. Radioimmunoassays were used to determine plasma progesterone, estrogen, and prolactin (indirect measurement of decidual luteotropin) concentrations. Fetal survival among BaP-treated rats declined in a dose-dependent manner (25 micro g/m(3), 78.3% per litter; 75 micro g/m(3), 38.0% per litter; 100 micro g/m(3), 33.8% per litter; P<0.05) compared with CB (96.7% per litter) and UNC (98.9% per litter). Plasma progesterone, estrogen, and prolactin concentrations also declined as a result of subacute exposure of rats to BaP compared to controls. These data suggest that inhaled BaP compromised fetal survival and consequently luteotropic activity in the exposed animals.