BACKGROUND: Nitric oxide plays an important role in bone metabolism. However, the effects of different doses of L-arginine, nitric oxide substrate, on the healing of osteoporotic fractures remain unclear. OBJECTIVE: To investigate the influence of different doses of L-arginine on the healing of osteoporotic fractures and blood biochemistry in rats. METHODS: A total of 50 female Wistar rats, aged 6-month-old, were randomly divided into sham-surgery (n=10) and osteoporosis (bilateral ovariectomy, n=40). After osteoporosis model was established, left middle femoral fractures were made in al 50 rats, and the osteoporosis group was further divided into four groups, low, middle and high dose of L-arginine, and control groups. The L-arginine groups were intraperitoneal y injected with 1, 3, and 5 mg/kg L-arginine at the second day fol owing surgery, while the control and sham-surgery groups were injected with the same volume of normal saline. At 8 weeks, the lumbar and cal us bone mineral density, serum nitric oxide, and nitric oxide synthase were detected. Meanwhile, the bone cal us histological examination was conducted. RESULTS AND CONCLUSION: During fracture healing, osteoporosis rats showed a low level of serum nitric oxide and nitric oxide synthase compared with normal fractured rats (P < 0.05). L-arginine can improve the concentration of serum nitric oxide and nitric oxide synthase in osteoporosis rats. Moreover, middle dose of L-arginine can increase the cal us and lumbar spine bone mineral density of osteoporosis rats, so the number and continuity of bone trabecula were enhanced. These findings suggest that middle dose of L-arginine (3 mg/kg) can promote healing process of osteoporotic fractures and improve osteoporosis.

Objective To investigate the safety of preoperative hepatic and regional arterial infusion chemotherapy in the prevention of liver metastasis and improving survival after curative colorectal cancer resection.Methods Patients admitted from 2001 to 2007 with Stage Ⅱ or Stage Ⅲ colorectal cancer were randomly assigned to receive preoperative hepatic and regional arterial infusion chemotherapy (PHRAIC group,n=256)or surgery alone(control group,n=253).Toxity of liver,hematology,immunology and post-operative complication of PHRAIC and the control were evaluated.Results Grade Ⅲ hepatic toxity,leukemia,anemia and platelet decrease in PHRAIC group was 3.1%(8/256),5.5% (14/256),7.4%(19/256)and 6.6%(17/256).There were no grade Ⅳ toxities,and all the patients in PHRAIC group received surgery.Morbidity rate in PHRAIC and the control group was 9.8%(25/256)vs 8.3%(21/253)(X2=1.86,P＞0.05).All patients were followed up,with mean follow up of 42±14 months until Oct 30.2007.For stage Ⅲ patients,5-year overall survival and liver metastasis rate were 81.0% in PHRAIc group vs.60.4% in control group(X2=5.15,P＜0.05)and 18.9%(28/148)vs 27.3%(41/150)(X2=5.41,P＜0.05),respectively.Conclusion Preoperative hepatic and regional arterial infusion chemotherapy 7 days before surgery was safe and could reduce liver metastasis and improve survival rate in patients with Stage Ⅲ colorectal cancer.