Determination of the median lethal dose of zinc gluconate in mice and safety evaluation.

BACKGROUND: Zinc Gluconate (ZG) is a safe and effective supplement for zinc. However, there is limited research on the optimal dosage for intravenous injection and the safety evaluation of animal models for ZG. This study aims to determine the safe dose range of ZG for intravenous injection in C57BL/6J mice. METHODS: A Dose titration experiment was conducted to determine the LD50 and 95% confidence interval (95%CI) of ZG in mice. Based on the LD50, four sub-lethal doses (SLD) of ZG were evaluated. Following three injections of each SLD and monitoring for seven days, serum zinc levels were measured, and pathological changes in the liver, kidney, and spleen tissues of mice were determined by histological staining. RESULTS: The dose titration experiment determined the LD50 of ZG in mice to be 39.6 mg/kg, with a 95%CI of 31.8-49.3 mg/kg. There was a statistically significant difference in the overall serum zinc levels (H = 36.912, P < 0.001) following SLD administration. Pairwise comparisons showed that the serum zinc levels of the 1/2 LD50 and 3/4 LD50 groups were significantly higher than those of the control group (P < 0.001); the serum zinc level of the 3/4 LD50 group was significantly higher than those of the 1/8 LD50 and 1/4 LD50 groups (P < 0.05). There was a positive correlation between the different SLDs of ZG and the serum zinc levels in mice (rs = 0.973, P < 0.001). H&E staining showed no significant histological abnormalities or lesions in the liver, kidney, and spleen tissues of mice in all experimental groups. CONCLUSION: The appropriate dose range of ZG for intravenous injection in C57BL/6J mice was clarified, providing a reference for future experimental research.

Analgesic therapy improves arterial endothelial function following non-cardiovascular surgery: A randomized, placebo-controlled trial.

Pain subsequent to non-cardiac surgery may affect the endothelial function, which in turn contributes to myocardial injury (MI). The present study examined whether effective pain control is able to improve the postoperative endothelial function. Patients (n=160) undergoing laparoscopic cholecystectomy were randomly assigned into two groups, treated with tramadol analgesic or saline (placebo) following surgery. On preoperative day 1 (baseline) and postoperatively at 2 h, 1 day and 5 days, pain was assessed on a visual analogue scale (VAS), and B-mode ultrasound was used to measure brachial endothelium-dependent flow-mediated dilation (FMD) and nitroglycerin-induced dilation. At 2 h postoperatively, the FMD in the two groups was significantly lower compared with that at the other three time points (P≤0.005), while VAS was significantly higher (P<0.05). Patients in the tramadol group presented significantly reduced VAS values in comparison with those in the placebo group at 2 h and 1 day postoperatively (P=0.013 and 0.031, respectively), as well as significantly higher FMD at 2 h (6.7±1.5 vs. 6.0±1.7%; P=0.001) and 1 day postoperatively (7.3±1.3 vs. 6.9±1.4%; P=0.03). A VAS score of <5 was independently associated with postoperative FMD of ≥7 (odds ratio, 2.5; 95% confidence interval, 1.0-6.0; P=0.047). Backward multivariate linear regression also demonstrated that FMD was independently correlated with age and VAS score (B=-1.403, P=0.011; B=-0.579, P=0.003). The response to nitroglycerin-induced dilation remained stable in all patients at baseline and at all postoperative time points. In conclusion, analgesic treatment may improve the arterial endothelial function following non-cardiac surgery, which may help prevent postoperative MI.

[Resistance stability of rice varieties to different biotypes of brown planthopper].

In order to develop an effective analytical and monitoring method in breeding rice varieties with higher resistance stability to brown planthopper (BPH), Tai's method (1971) was employed to estimate the resistance stability of twelve rice varieties to different biotypes of BPH. It was shown that light intensity, seedling age, and nitrogen application rate had significant effects on the resistance performance and stability of rice varieties to different BPH biotypes. Among the varieties with resistance to BPH biotype II, the RHT, RP1976-18-6-4-2, and Ptb33 showed stable, IR56 showed unstable, while IR36 and ASD7 showed the most unstable resistance; whereas among the varieties susceptible to BPH biotype II, the TN1 showed stable, Guihuazhan, Foshanyouzhan and IR26 showed relatively stable, while Guojing No. 4 and Mudgo showed unstable susceptibility. For the rice varieties resistant to BPH biotype Bangladesh, the RHT, RP1976-18-64-2 and Ptb33 presented unstable, and IR56 presented very unstable resistance; whereas for the varieties susceptible to BPH biotype Bangladesh, the Guihuazhan, Foshanyouzhan and IR26 performed stable, TN1 and IR36 performed unstable, and Guojing No. 4, Mudgo and ASD7 performed the most unstable susceptibility.