Effect of hydroxyapatite nanoparticles on the growth and p53/c-Myc protein expression of implanted hepatic VX2 tumor in rabbits by intravenous injection.

AIM: To evaluate the effect of hydroxyapatite nano-particles (Nano HAP) by intravenous injection on the inhibition of implanted hepatic VX(2) tumor growth in rabbits and cell p53/c-Myc protein expression. METHODS: 60 hepatic VX(2) tumor-bearing rabbits was randomly divided into five groups. Nano HAP collosol 20 mg/kg, 40 mg/kg, 5-FU solutions 20 mg/mL, mixed liquor of 5-FU solution 20 mg/mL and Nano HAP collosol 20 mg/kg were infused by vein, normal saline conducted as the control. The general state, weight, liver function and gross tumor volume were detected dynamically. The expression of p53 and c-Myc gene protein in tumor tissue was detected by immunohistochemistry methods. RESULTS: The growth of implanted hepatic VX(2) tumors was significantly inhibited in all therapy groups, 3 wk after the injection, the tumor control rates in Nano HAP collosol groups were 25.5% and 32.5% respectively, and the gross tumor volumes were obviously less than that of control group. (24.81 +/- 5.17 and 22.73 +/- 4.23 vs 33.32 +/- 5.26, P<0.05). The tumor control rate of 5-FU group was 43.7% (18.74 +/- 4.40 vs 33.32 +/- 5.26, P<0.05), but the general state of the animals after injection aggravated; and the adverse reaction in the drug combination group obviously decreased. Due to the effect of Nano HAP, the positive expression of tumor associated the mutated p53 and c-Myc in tumor tissue was decreased obviously compared with the control group. CONCLUSION: Nano HAP has evident inhibitory action on rabbit implanted hepatic VX(2) tumor in vivo, which may be the result of decreasing the expression of the mutated p53 and c-myc, and drug combination can obviously decrease the adverse reaction of 5-FU.

Effects of hydroxyapatite nanoparticles on proliferation and apoptosis of human hepatoma BEL-7402 cells.

AIM: To study the effect of hydroxyapatite (HAP) nanoparticles on human hepatoma cell line BEL-7402 in vitro. METHODS: The human hepatoma cell line BEL-7402 was cultured and treated with HAP nanoparticles at various concentrations. Growth suppression was detected with MTT colorimetric assay, cell apoptotic alterations were evaluated by cytochemical staining (Hoechst 33258), transmission electron microscopy (TEM), and flow cytometry (FCM). RESULTS: HAP nanoparticles inhibited the growth of hepatoma cells in a dose-dependent manner, with IC(50) values of 29.30 mg/L. Treated with 50-200 mg/L HAP nanoparticles for 48 h, BEL-7402 cells apoptosis with nuclear chromatin condensation and fragmentation as well as cell shrinkage and the formation of apoptotic bodies were observed under cytochemical staining and transmission electron microscopy. FCM analysis showed hypodiploid peaks on histogram, the apoptotic rates at the concentrations of 50, 75, 100, 150 and 200 mg/L of HAP nanoparticles were 20.35+/-2.23 %, 25.35+/-1.92 %, 29.34+/-4.61 %, 44.92+/-3.78 % and 53.64+/-3.49 %, respectively, which were all significantly higher than that of control group 2.23+/-0.14 %. There was a significant correlation between HAP nanoparticle concentration and apoptotic rate (r=0.994, P<0.01). CONCLUSION: HAP nanoparticles not only inhibit proliferation but also induce apoptosis of human hepatoma cell line BEL-7402 in vitro.

[Use of antiperistaltic cecoproctostomy in colorectal reconstruction].

OBJECTIVE: To explore the feasibility and functional outcome of antiperistaltic cecoproctostomy in colorectal reconstruction. METHODS: Fifty-six patients who underwent antiperistaltic cecoproctostomy were retrospectively studied. Indications for antiperistaltic cecoproctostomy included slow transit constipation(n=44), synchronous colon cancer or colonic polyps(n=5), acute obstructing left colon carcinoma(n=4), and adult megacolon(n=3). RESULTS: Short-term postoperative complications included wound infections(n=5), 3 lymphatic leakages(n=3), and inflammatory small bowel obstruction(n=1). One month after antiperistaltic cecoproctostomy, the median frequency of daily bowel movement was 4.0(range, 2-6). After a median follow-up of 4 years(range, 1 month to 7 years), the median daily bowel frequency was 2.5(range, 0.5-4.0). Five patients suffered from long-term postoperative complications including small bowel obstruction(n=3), incision hernia(n=1), and mild cecal dilatation(n=1). The mean Wexner incontinence score was 4.2±1.1. CONCLUSION: Antiperistaltic cecoproctostomy is safe and effective for colorectal reconstruction.

[Efficacy comparison of subtotal colectomy with antiperistaltic cecoproctostomy and total colectomy with ileorectal anastomosis for patients with slow transit constipation].

OBJECTIVE: To compare the efficacy between subtotal colectomy with antiperistaltic cecoproctostomy and total colectomy with ileorectal anastomosis (TAC-IRA) for patients with severe refractory slow transit constipation(STC). METHODS: During 1999 to 2002, TAC-IRA was the preferred procedure for 20 STC patients in our department. From 2003 to 2005, 17 STC patients underwent subtotal colectomy plus antiperistaltic cecoproctostomy. Clinical data of the two groups were collected and compared retrospectively. RESULTS: There were no significant differences in basic preoperative clinical data between the two groups. During the follow-up period, the time of daily defecation in the antiperistaltic cecoproctostomy group was less than that of TAC-IRA group (2.4+/-0.9 vs 3.4+/-0.8, P=0.0014), meanwhile the Wexner continence score was significantly lower in the antiperistaltic cecoproctostomy group (4.3+/-1.8 vs 5.8+/-1.9, P=0.0223). Barium enema after subtotal colectomy showed that residual ascending colon and cecum presented a sign of "reservoir". CONCLUSION: Subtotal colectomy with antiperistaltic cecoproctostomy is a better method for appropriately selected patients with STC than TAC-IRA.