[Efficacy comparison of minimally invasive atlantoaxial mass fusion and open atlantoaxial fusion in the treatment of atlantoaxial dislocation].

Objective: To compare the clinical effects of minimally invasive intermuscular atlantoaxial lateral mass fusion (Mis-PALF) and open atlantoaxial fusion in patients with atlantoaxial dislocation. Methods: The clinical data of patients with atlantoaxial dislocation who received Mis-PALF operation (17 cases) or open atlantoaxial fusion (88 cases, as control) in the Third Hospital of Peking University from September 2015 to September 2021 were analyzed retrospectively. In Mis-PALF group, there were 9 males and 8 females, aged (45.8±19.8) years; and there were 48 males and 40 females in the control group, aged (50.0±13.9) years. The operation time, perioperative blood loss, postoperative body temperature, postoperative pain [assessed with visual analogue scale (VAS)], postoperative additional analgesic drugs, postoperative hospitalization time, the improvement rate of Japanese Orthopedic Association (JOA) scores of spinal cord function in three-months follow-up and complications were compared between the two groups. Results: Mis-PALF group had less perioperative blood loss than control group [(111.8±35.9)ml vs (362.9±18.6)ml, P<0.01], shorter hospitalization time [(3.06±0.63) days vs (4.24±0.14) days, P<0.01] and fewer additional analgesic drugs (3/17 vs 56/88, P<0.01). There was no significant difference between the Mis-PALF and control group in operation time [(125±7)min vs (113±8)min, P=0.525], patients with fever(11/17 vs 37/88, P=0.086) or postoperative pain (1/17 vs 13/88, P=0.357), the improvement rate of JOA score (66.9%±28.8% vs 74.2%±28.6%, P=0.409) and complications rate (1/17 vs 3/88, P=1.000). Conclusion: Mis-PALF can significantly reduce the perioperative blood loss, shorten the postoperative hospitalization time and the additionally use of analgesic drugs without increasing complications.

Evidence that lipid peroxidation products bind to DNA in liver cells.

Three lines of evidence are presented indicating the association of lipid peroxidation products with DNA in liver cells, labeled with [3H]arachidonic acid, in the presence of Fe(2+)-DTPA: (1) the nuclear DNA isolated from treated cells had higher radioactivity, compared to controls and the radioactivity increased with longer incubation times, (2) lipid-DNA adducts with a characteristic fluorescence spectrum were formed during the incubation with Fe(2+)-DTPA; (3) the association of peroxidation products with DNA could be inhibited by vitamin E and BHT. Compared with control DNA, purified lipid-DNA adducts showed a decrease of hyperchromicity and melting point, and partial resistance to hydrolysis by DNase I. On the other hand, the repair test shows that the lipid-DNA adducts in cells were not repaired by 4 h after removal of Fe(2+)-DTPA. A decrease in cell viability and in the activity of O6-alkylguanine acceptor protein was also observed with increasing incubation time. These data suggest that the lipid-DNA association, an oxidative DNA damage, occurs in cells treated by Fe(2+)-DTPA and could result in cytotoxicity if not repaired.

Effect of natural antioxidant tanshinone II-A on DNA damage by lipid peroxidation in liver cells.

Tanshinone II-A (TSII-A) isolated from the root of Salvia miltorrhiza Bunge, a traditional medicine in China, is a derivative of phenanthrenequinone, which is known to have antioxidant properties. In the present study, effects of TSII-A on DNA damage by lipid peroxidation were investigated using liver cells, labeled with [3H] arachidonic acid, in the presence of FeCl2-DTPA. The results show that the nuclear DNA isolated from treated cells had higher radioactivity compared to controls and the radioactivity increased with longer incubation times. Purified lipid-DNA adducts had a characteristic fluorescent spectra and showed a decrease of hyperchromicity and melting point. TSII-A could inhibit the association of peroxidation products with DNA in liver cells and prevent a decrease in cell viability and in the the activity of O6-methylguanine acceptor protein with increasing incubation time. Compared with other antioxidants, TSII-A had a higher inhibitory ratio, which was similar to vitamin E and butylated hydroxy-toluene (BHT), but markedly stronger than NaN3, mannatol, and superoxide dismutase (SOD). These data suggest that TSII-A represents a new and effective antioxidant that inhibits the association of lipid peroxidation products with DNA. Its protective effect may be through breaking the chain reactions of peroxidation by scavenging lipid free radicals, thereby decreasing their cytotoxicity.