[Light Absorption and Fluorescence Characteristics of Atmospheric Water-soluble Organic Compounds and Humic-like Substances During the Winter Season in Guangzhou].

The light absorption and fluorescence characteristics of atmospheric water-soluble organic compounds (WSOC) and humic-like substances (HULIS) during the winter season in Guangzhou were examined using UV-vis spectroscopy and excitation-emission matrix spectroscopy combined with parallel factor analysis (EEM-PARAFAC). The results showed that the SUVA254, HIX, and MAE365 values of HULIS were higher than those of WSOC, suggesting that the former had higher aromaticity, humification, and light-absorption capacity in winter atmospheric PM2.5 in Guangzhou. EEM-PARAFAC analysis identified three fluorescence components, including fulvic-like acid (C1), humic-like acid (C2), and protein-like (C3) components. The total humic-like components (C1+C2) accounted for 78% and 85% for WSOC and HULIS, respectively, which indicated that humic-like fluorescence components were the major components for both WSOC and HULIS and that HULIS were enriched with the dominant humic-like fluorophores. In addition, the aromaticity, humification, light-absorbing capacity, and C2 levels of WSOC and HULIS during the haze episode were significantly higher than those in the non-haze episode. This suggested that the water-soluble organics with higher molecular weights and stronger light-absorption capacities tended to form during the haze episode. The correlations analysis revealed strong negative correlations between C1 levels of WSOC and HULIS and HIX, MAE365, OCsec, K+, SO42-, and NH4+. Additionally, strong positive correlations were observed between C2 levels and the same factors. These results implied that the decrease in C1 and increase in C2 might lead to increased humification and light-absorption in WSOC and HULIS, and biomass burning and secondary organic aerosols might contribute to the C2 component.

[Impact of subchronic exposure to low-dose nano-nickel oxide on the reproductive function and offspring of male rats].

OBJECTIVE: To investigate the influence of subchronic exposure to low-dose subchronic nano-nickel oxide (NNO) on the reproductive function of male rats and embryonic development of the pregnant rats. METHODS: Fifty normal healthy male SD rats weighing 180－220 g were randomly divided into five groups of equal number, negative control, 4 mg/ml micro-nickel oxide (MNO), and 0.16, 0.8 and 4 mg/ml NNO, those of the latter four groups exposed to MNO or NNO by non-contact intratracheal instillation once every 3 days for 60 days, and then all mated with normal adult female rats in the ratio of 1∶2. After the female animals were confirmed to be pregnant, the males were sacrificed and the weights of the body, testis and epididymis obtained, followed by calculation of the visceral coefficients, determination of epididymal sperm concentration and viability and the nickel contents in the blood and semen by atomic fluorescence spectrometry. The female rats were killed on the 20th day of gestation for counting of the implanted fertilized eggs and live, dead and resorbed fetuses. RESULTS: After 60 days of exposure, the rats of the NNO groups showed no statistically significant differences from those of the negative control and MNO groups in the weights of the body, testis and epididymis or visceral coefficients. Compared with the negative control group, the animals of the 0.8 and 4 mg/ml NNO groups exhibited markedly decreased sperm concentration (ï¼»9.36 ± 0.98ï¼½ vs ï¼»7.49 ± 1.46ï¼½ and ï¼»6.30 ± 1.36ï¼½ ×106/ml, P < 0.05) and viable sperm (ï¼»85.35 ± 9.16ï¼½% vs ï¼»68.26 ± 16.63ï¼½% and ï¼»65.88 ± 14.68ï¼½ %, P < 0.05), increased morphologically abnormal sperm (ï¼»8.30 ± 2.47ï¼½% vs ï¼»13.99 ± 4.87ï¼½% and ï¼»15.38 ± 8.86ï¼½ %, P < 0.05), and elevated rate of dead and resorbed fetuses (1.18% vs 6.89% and 7.37%, P < 0.05), blood nickel content (ï¼»0.13 ± 0.16ï¼½ vs ï¼»0.52 ± 0.34ï¼½ and ï¼»0.82 ± 0.44ï¼½ mg/L, P < 0.05) and semen nickel content (ï¼»0.08 ± 0.13ï¼½ vs ï¼»0.35 ± 0.23ï¼½ and ï¼»0.63 ± 0.61ï¼½ mg/L, P < 0.05). The nickel level in the semen was correlated significantly with that in the blood (r = 0.912, P <0.01), negatively with the rate of viable sperm (r = －0.879, P <0.01) and positively with the percentage of morphologically abnormal sperm (r = －0.898, P <0.01). CONCLUSIONS: Sixty-day exposure to nano-nickel oxide at 0.8 and 4 mg/ml can produce reproductive toxicity in male rats and result in fetal abnormality in the females, while that at 0.16 mg/ml has no significant toxic effect on the reproductive function of the males.

Methylation of the suppressor of cytokine signaling 3 gene (SOCS3) in bladder cancer.

BACKGROUND: It has been identified consequences of dysregulation of JAK-STAT signalling, particularly in regard to JAK-STAT signalling that has been shown to have roles in the oncogenesis of several cell types. SOCS3 protein, the negative regulatory protein of JAK-STAT signaling pathway, may also plays critical regulatory roles in cancer initiation and progression. SOCS3 promoter hypermethylation has often been identified in human cancers; however, the precise role of SOCS3 in bladder cancer is unclear. METHODS: The methylation status of the SOCS3 was analyzed in an age (±5 years) and sex-matched case-control study, including 112 bladder cancer cases and 118 normal controls, using the MassARRAY EpiTYPER system. RESULTS: Methylation rate of JAK2, SOCS3 and STAT3 gene were shown to vary among different CpG island. The methylation rate of SOCS3 gene was also much higher in BCa than in normal control participants, but the methylation rate of JAK2, STAT3 gene weren't different in Bca and normal control participants. CONCLUSIONS: Our study demonstrates that promoter hypermethylation of SOCS3 gene is associated with BCa and thus, may serve as an independent prognostic biomarker.

Effects of advanced glycation end product modification on proximal tubule epithelial cell processing of albumin.

AIM: The goal of this work is to understand the cellular effects of advanced glycation end product (AGE)-modified protein on renal proximal tubule cells. BACKGROUND: A major function of the proximal tubule is to reabsorb and process filtered proteins. Diabetes is characterized by increased quantities of tissue and circulating proteins modified by AGEs. Therefore in diabetes, plasma proteins filtered at the glomerulus and presented to the renal proximal tubule are likely to be highly modified by AGEs. METHODS: The model system was electrically resistant polarized renal proximal tubular epithelial cells in monolayer culture. The model proteins comprise a well-characterized AGE, methylglyoxal-modified bovine serum albumin (MGO-BSA), and unmodified BSA. RESULTS: Renal proximal tubular cells handle MGO-BSA and native BSA in markedly disparate ways, including differences in: (1) kinetics of binding, uptake, and intracellular accumulation, (2) processing and fragmentation, and (3) patterns of electrical conductance paralleling temporal changes in binding, uptake and processing. CONCLUSION: These differences support the idea that abnormal protein processing by the renal tubule can be caused by abnormal proteins, thereby forging a conceptual link between the pathogenic role of AGEs and early changes in tubular function that can lead to hypertrophy and nephropathy in diabetes.

Cellular oxidant stress and advanced glycation endproducts of albumin: caveats of the dichlorofluorescein assay.

In order to understand the mechanism by which advanced glycation endproducts (AGEs) elicit oxidative stress, macrophage-like RAW264.7 cells were exposed to various AGE-albumins, and oxidant stress was estimated from the fluorescence of oxidized dichlorofluorescein using the microtiter plate assay. Strongest fluorescence was observed with methylglyoxal modified albumin (MGO-BSA) compared with native albumin. Similar effects that were prevented by arginine coincubation were seen with phenylglyoxal-BSA. MGO-BSA had increased affinity for Cu(2+) and Ca(2+), but was conformationally similar to native albumin. Surprisingly, the mere addition of unmodified albumin to cells suppressed the fluorescence of oxidized DCF. While, several site-directed mutants of human serum albumin (HSA), including C34S and recombinant domains II and III retained fluorescence suppressing activity, proteolytic digests, recombinant domain I, and several nonalbumin proteins failed to suppress. Kinetic and ANS binding studies suggested albumin quenches DCF fluorescence by binding to hydrophobic pockets in domains II and III and that MGO-BSA is less hydrophobic than BSA. Finally, BSA also prevented H(2)O(2) catalyzed DCF fluorescence more potently than MGO-BSA. These studies reveal important caveats of the widely used dichlorofluorescein assay and suggest methods other than the microtiter plate assay are needed to accurately assess cellular oxidant stress in presence of native or modified albumin.