γ-Synuclein Expression Is a Malignant Index in Oral Squamous Cell Carcinoma

Dysregulation of γ-synuclein (SNCG) has been reported in many cancers; however, its role in cancer development is still controversial. Here, we examined the potential involvement of DNA methylation in regulating SNCG and its role in oral squamous cell carcinoma (OSCC). We used 8 OSCC cell lines to investigate SNCG methylation and expression. SNCG methylation was examination by methylation-specific polymerase chain reaction and bisulfate sequencing. Cells showing a high degree of SNCG methylation were treated with 5-aza (methylation inhibitor), and changes in their methylation and expression profiles were analyzed. Functional effects of SNCG in OSCC were examined by its overexpression and knockdown. Additionally, methylation and expression of SNCG in OSCC tissues were investigated and correlated with clinicopathologic features. All OSCC cells showed detectable SNCG expression at the mRNA and protein levels. Methylation-specific polymerase chain reaction and bisulfate sequencing revealed high SNCG expression in SCC25 cells with the unmethylated allele, and their 15 CpG islands were unmethylated. The methylated allele was detected only in OEC-M1 cells exhibiting low SNCG expression, and their CpG islands were partially methylated. 5-aza treatment in OEC-M1 cells attenuated methylation and restored SNCG expression. SNCG overexpression increased colony forming, migration, and invasion abilities in OEC-M1 cells. Silencing SNCG in SCC25 cells suppressed these behaviors. All 25 tumor-adjacent normal tissues were negative for SNCG immunostaining. SNCG upregulation was frequently observed in dysplastic and OSCC tissues. Positive SNCG expression was found in 45% (37 of 82) OSCC tissues. Positive SNCG expression in OSCC significantly correlated with cancer staging and lymph node metastasis. However, SNCG methylation did not correlate with its expression and clinicopathologic variables in OSCC tissues. DNA methylation may participate in regulating SNCG expression in some OSCC cells. SNCG upregulation could be involved in OSCC progression.

Fabrication and characterization of high-T(c) YBa(2)Cu(3)O(7-x) nanoSQUIDs made by focused ion beam milling

We have fabricated high-T(c) nanoscale superconducting quantum interference devices (nanoSQUIDs) with a hole size of 250 nm × 250 nm based on a 100 nm bridge at 77 K by focused ion beam milling and ion implantation. At 78 K, the curve of the voltage branch became roughly linear and agreed with the Josephson-like behavior. The sample exhibited strong flux flow behavior at temperatures under 76 K. The voltage flux characteristic curves, V -I(mod), of the nanoSQUID at different bias currents at 78 K were observed. Typically, critical currents of 15 µA and peak-to-peak values of the voltage flux transfer function of 3.7 µV were measured. The measured data strongly suggest that the weak link structure could be a superconducting metal with a critical temperature T(c)' smaller than that (T(c)) of other YBa(2)Cu(3)O(7-x) (YBCO) films. This fabrication method of combining a nanobridge and ion implantation can improve the yield of nanojunctions and nanoSQUIDs.

Dopamine overload visualized in the basal ganglia of rabbit brain during heatstroke can be suppressed by hypothermia

The present study assesses the changes of dopamine levels in the basal ganglia (BG) of rabbit brain during heatstroke with or without hypothermia therapy. The dopamine levels were determined by using 6(F18) fluoro-L-dopa (FDOPA) positron emission tomography (PET) scan. Heatstroke was induced by exposing the anesthetized rabbits to a high blanket temperature (T(blanket)) of 45 degrees C. Hypothermia therapy was accomplished by decreasing T(blanket) from 45 to 16 degrees C. Regions-of-interest were carefully selected on the BG and cerebellum (C). The uptake ratio of FDOPA was defined as the mean counts per pixel from BG divided by the mean counts from C. BG/C ratios represent the dopamine levels of BG. The results showed that the values of mean arterial pressure (MAP) in heatstroke rabbits without hypothermia therapy were significantly lower than those in normothermic controls. However, BG/C FDOPA ratios were greater. Both the arterial hypotension and the increased BG/C FDOPA ratios observed during heatstroke were all reduced after hypothermia therapy. Our data demonstrate that the dopamine overload visualized in the BG of rabbit brain during heatstroke can be suppressed by hypothermia therapy.

Menadione-induced cell degeneration is related to lipid peroxidation in human cancer cells

The role of lipid peroxidation, intracellular glutathione and Ca2+ concentration in menadione-mediated toxicity was investigated in human hepatoma cell lines, Hep G2 and Hep 3B, and in human leukemia cell lines, CCRF-CEM and MOLT-3. Incubation of these cells with 80 microM menadione at 37 degrees C resulted in depletion of intracellular glutathione, increased intracellular Ca2+, and increased lipid peroxidation, events leading to cell degeneration. The sensitivity of these cells to menadione, in order, was: Hep G2 cells > Hep 3B cells > CCRF-CEM cells and MOLT-3 cells. The extent of menadione-induced lipid peroxidation in different cell types followed the same order as did their susceptibility to menadione-induced cell degeneration. The menadione-induced depletion in glutathione level was in the following sequence: Hep G2 cells > MOLT-3 and CCRF-CEM cells > Hep 3B cells. The extent of the menadione-induced increase in the intracellular Ca2+ concentration was: Hep G2 cells > Molt-3 cells > CCRF-CEM cells and Hep 3B cells. Pre-treatment of Hep G2 cells with 20 mM deferoxamine mesylate, an iron chelator, reduced both the menadione-induced cell degeneration and lipid peroxidation; however, it did not prevent the menadione-induced increase in intracellular Ca2+ nor the depletion of glutathione. These data suggest that menadione-induced cell degeneration is directly linked to lipid peroxidation, and that it is less related to the rise in intracellular Ca2+ and the depletion in glutathione content. Dicumarol (an inhibitor of DT diaphorase) enhanced the capacity of menadione to induce Hep 3B cell degeneration from 71.3% to 86.2% after 120 min of menadione treatment at 37 degrees C, but did not have this effect in Hep G2, CCRF-CEM or MOLT-3 cells. The activities of DT diaphorase were 52.4, 39.6, 1.5 and 1.8 nmol cytochrome c reduced/min/mg protein in Hep G2, Hep 3B, CCRF-CEM and MOLT-3 cells, respectively. The activity of DT diaphorase was much higher in Hep G2 cells than in the other cells. It seems that DT diaphorase may not, as suggested by others, protect against cell degeneration by quinones, such as menadione.

Criterion for the Prevention of Core Fracture During Extrusion of Bimetal Rods

Based on the upper-bound theorem in limit analysis, a theoretical model for core fracture in bimetal rods during extrusion has been developed and a fracture criterion established. The variables affecting core fracture are: reduction in area (r%), die geometry, friction (m), relative size of the core and relative strength of the core. Within the wide range of possible combinations of these process variables, only a small range permits extrusion without fracture. With suitable modifications the present analysis can be extended to develop criteria for sleeve fracture during extrusion and for both core and sleeve fracture during drawing.