MnSOD expression inhibited by electromagnetic pulse radiation in the rat testis.

Male Sprague Dawley rats were exposed to EMP irradiation of 100 kV/m peak-to-peak e-field intensity and different numbers of pulses. Rat sperm samples were prepared for analysis of sperm qualities; Testes were assessed by transmission electron microscopy and serum hormone concentrations were examined by radioimmunoassay; Enzymatic activities of Total-superoxide dismutase(T-SOD) and manganese-superoxide dismutase (MnSOD), the mRNA levels of MnSOD and cuprozinc-superoxide dismutase (CuZnSOD), and the density of malondialdehyde (MDA) were also determined. EMP irradiation did not affect spermatozoon morphology, micronucleus formation rate, sperm number or viability, but the acrosin reaction rate decreased at 24 h and 48 h and recovered by 72 h after irradiation as compared to the controls. The ultrastructure of rat testis displayed more serious damage at 24 h than at other time points (6 h, 12 h, 48 h). Serum levels of luteotrophic hormone (LH) and testosterone (T) were elevated in irradiated rats as compared to controls. After irradiation, enzymatic activities of T-SOD and MnSOD were reduced by 24 h, consistent with the changes observed in MnSOD mRNA expression; MDA content increased at 6 h in turn. These studies have quantified the morphological damage and dysfunction in the rat reproductive system induced by EMP. The mechanism of EMP induced damage may be associated with the inhibition of MnSOD expression.

Expression of chimeric antibody in mammalian cells using dicistronic expression vector.

A dicistronic expression vector was constructed for Chinese hamster ovary (CHO) cells that produce both selectable marker-DHFR (dihydrofolate reductase) gene and recombinant antibody cDNA from a single primary transcript via differential splicing. The vector was derived from a pDHL vector and contained the human constant region cDNA so that any human-mouse chimeric antibodies could be expressed. The expression vector produced stable CHO cell clones that secreted nearly double the amount of chimeric antibodies than produced by conventional expression approaches, where the DHFR gene and relevant cDNA are controlled by separate transcription cassettes. Clones with increased expression of interested genes can be efficiently generated by selection in medium containing a gradually increasing amount of methotrexate. The dicistronic expression system using incomplete splicing DHFR gene strategy thus provides a convenient, high-level, and rapid expression of chimeric antibodies.

[Applied anatomy study related to implants in the temporal bone region].

OBJECTIVE: To study the bone anatomic structure of the temporal bone region and provide reference in implant surgery in this region. METHODS: Manual quantitative measurements of the bone structure were performed in 73 skull specimens (38 from male and 35 from female). RESULTS: In the area of 8:00-11:00 (right ear) and 16-22 mm from center of the external auditory canal in the temporal bone region, the minimum bone thickness is as follows: 11:00: 6.77 mm in male, 5.18 mm in female; 10:00: 8.60 mm in male, 6.77 mm in female; 9:00: 9.85 mm in male, 7.30 mm in female; 8:00: 14.50 mm in male, 10.80 mm in female. CONCLUSION: (1) In the temporal bone region, the area of 8:00-11:00 (right ear) and 16-22 mm from center of the external auditory canal offers sufficient bone for implants. The length of implants should be as follows: 11:00: 4-5 mm in male, 3-4 mm in female; 10:00: 4-7 mm in male, 4-5 mm in female; 9:00: 4-8 mm in male, 4-6 mm in female; 8:00: 4-12 mm in male, 4-8 mm in female. (2) Towards the external auditory canal and from 12:00 to 11:00, 10:00 to 8:00, the bone became thicker, so, if no ample bone is available in the initial site, the location should be shifted anti-clockwise in right side (clockwise in left side) and closer to the external auditory canal. (3) The differences between male and female are statistically significant in the temporal bone region, so they should be treated distinguishingly during the clinical practices.