[Effect of aluminum trichloride on abnormal phosphorylation of tau protein in SH-SY5Y cells].

OBJECTIVE: To investigate the effect of aluminum trichloride on the abnormal phosphorylation of tau protein in SH-SY5Y cells. METHODS: SH-SY5Y cells were assigned to control group and aluminum trichloride exposure groups (200, 400, and 800 µmol/L Al(3+)). The cell morphology was observed after 48 hours of exposure; the cell viability was measured by CCK-8 assay; total protein was extracted from the cells, and the expression of phospho-tau (p-tau) 181, 231, 262, and 396 and tau 5 was measured by Western blot. RESULTS: As the Al(3+) concentration rose, the number of living SH-SY5Y cells decreased, and the synapses of the cells retracted. The viability of cells exposed to 800 µmol/L Al(3+) was significantly lower than that of the control group (P < 0.05). The 200, 400, and 800 µmol/L Al(3+) exposure groups showed significantly higher expression of p-tau 181, 231, and 396 and tau5 than the control group (P < 0.05), and the 800 µmol/L Al(3+) exposure group showed significantly higher expression of p-tau 262 than the control group (P < 0.05). CONCLUSION: Under the present experimental conditions, aluminum trichloride has toxic effect on SH-SY5Y cells and can lead to abnormal expression of p-tau 181, 231, and 396 and tau 5 at low Al(3+) concentration.

[Effect of aluminum exposure on cognitive function in electrolytic workers and its influential factors].

OBJECTIVE: To clarify the effect of aluminum exposure on the cognitive function in electrolytic workers and the prevalence of mild cognitive impairment (MCI) among them by prevalence survey, and to investigate its influential factors. METHODS: Sixty-six retired workers from the electrolysis workshop of an electrolytic aluminum plant were selected as an aluminum exposure group, while 70 retired workers from a flour mill in the same region were selected as a control group. MCI patients were screened out by Mini-Mental State Examination (MMSE); the blood aluminum level was measured by inductively coupled plasma-mass spectrometry; multivariate statistical analysis was used to investigate the influential factors for MMSE scores and the correlation between blood aluminum level and MCI prevalence. RESULTS: The aluminum exposure group showed a significantly higher blood aluminum level than the control group (25.18 ± 2.65 µg/L vs 9.97 ± 2.83 µg/L, P < 0.01). The total MMSE score of the aluminum exposure group (26.13 ± 2.57) was significantly lower than that of the control group (27.89 ± 1.91) (P < 0.05), particularly the scores on time and place orientation, short-term memory, calculation ability, and language skill (P < 0.05). The detection rate of MCI was significantly higher in the aluminum exposure group (18.2%) than in the control group (5.7%) (P < 0.01). The main influential factors for MMSE scores were gender, age, education level, and blood aluminum level. The logistic regression analysis indicated that the MCI prevalence was significantly correlated with blood aluminum level in the study population (OR = 1.168, P < 0.01). CONCLUSION: Long-term exposure to aluminum can cause cognitive disorders in electrolytic workers and may be one of the risk factors for MCI. Advanced age, male, low education level, and high blood aluminum level may be high-risk factors for cognitive impairment.

Bonding of glass microfluidic chips at room temperatures.

A simple, room-temperature bonding process was developed for the fabrication of glass microfluidic chips. High-quality bonding with high yields (>95%) was achieved without the requirement of clean room facilities, programmed high-temperature furnaces, pressurized water sources, adhesives, or pressurizing weights. The plates to be bonded were sequentially prewashed with acetone, detergent, high-flow-rate (10-20 m/s) tap water, and absolute ethyl alcohol and were soaked in concentrated sulfuric acid for 8-12 h. The plates were again washed in high-flow-rate tap water for 5 min and, finally, with demineralized water. The plates were bonded by bringing the cleaned surfaces into close contact under a continuous flow of demineralized water and air-dried at room temperature for more than 3 h. This bonding process features simple operation, good smoothness of the plate surface, and high bonding yield. The procedures can be readily applied in any routine laboratory. The bonding strength of glass chips thus produced, measured using a shear force testing procedure, was higher than 6 kg/cm(2). The mechanism for the strong bonding strength is presumably related to the formation of a hydrolyzed layer on the plate surfaces after soaking the substrates in acid or water for extended periods. Microfluidic chips bonded by the above procedure were tested in the CE separation of fluorescein isothiocyanate-labeled amino acids.