Tissue residues and withdrawal time of moxidectin treatment of swine by topical pour-on application.

Moxidectin (MXD), an antiparasitic drug, is effective for a variety of external and internal parasites in companion and farm animals. This study aimed to calculate the withdrawal period by investigating the residue depletion of MXD in swine edible tissues after pouring at the dosage of 2.5 mg/kg B.W. The concentrations of MXD in swine edible tissues were determined by a modified preparation procedure based on HPLC-FLD. The method was validated giving LOD and LOQ of 0.5 µg/kg and 1 µg/kg respectively with measured recoveries ranging from 62.9%-89.2% at three different concentrations and a precision (RSD) of less or equal to 15.7%. The muscle, liver, kidney and fat tissues were collected at 0.5, 5, 10, 20, 25 d after administration. The results showed that fat was the target tissue with the highest concentration for MXD. The withdrawal period was 26 days for the MRL of 500 µg/kg in fat. The results provide fundamental information to ensure food safety and establishment of a rational medication regimen.

The enhanced ability of peripheral mononuclear cells differentiating into neural cells in term infants with good improvement suffering from severe hypoxic ischemic encephalopathy.

OBJECTIVE: It has been found that asphyxia influences proliferation and differentiation of brain neural stem cells in newborn animal models, and that peripheral blood stem cells play an important role in repairing brain damage. But it has not been reported yet whether asphyxia influences peripheral blood stem cells differentiating into neural cells, and whether with the progress of the disease there is a change of peripheral blood stem cells differentiating into neural cells in newborns with hypoxic ischemic encephalopathy (HIE). METHODS: Fifty term HIE infants were enrolled in research from March, 2007 to March, 2010. There were 10 cases of the severe HIE patients with good improvement, the severe HIE patients with poor improvement, the moderate HIE patients, the mild HIE patients and the controls, respectively. The peripheral mononuclear cells collected within 24 hours and on 7th day after birth were cultured in vitro for 10 days to differentiate into neural cells. The induced nestin positive cells were identified with Immunohistochemistry and counted. Findings : Within 24 hours after birth, there were no difference of induced nestin positive cells among the severe HIE patients with good improvement (68.99±7.85), the severe HIE patients with poor improvement (71.43±6.88), the moderate HIE patients (73.34±6.46), the mild HIE patients (70.46±6.66) and the controls (71.13±7.19, F=0.51, P=0.7). In the severe HIE patients with obvious improvement, the induced nestin positive cells from 7th day peripheral blood mononuclear cells (94.50±15.57) increased markedly compared with that within 24 hours (68.99±7.85, t=4.66, P<0.001), and were higher than the induced nestin positive cells from 7(th) day peripheral blood mononuclear cells in the severe HIE patients with no obvious improvement (94.50±15.57 vs 69.48±5.32, t=4.62, P<0.001). CONCLUSION: The ability of peripheral mononuclear cells differentiating into neural cells in term infants with good improvement suffering from severe HIE was enhanced, which may suggest possible relationship between the brain repair and the peripheral stem cells.