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Biomedical subjects

Y Du

Publications and source records attributed to Y Du.

205 records · Page 12Linked to original sources
PubMedDate not supplied

Pharmacokinetics of Astragaloside IV in rats by liquid chromatography coupled with tandem mass spectrometry.

Pharmacokinetics of Astragaloside IV (AGS-IV) in rats was studied by high performance liquid chromatography coupled with tandem mass spectrometry. The concentration in plasma was determined after i.v. administration of 1, 2, 4 mg/kg and p.o. administration of 20 mg/kg of AGS-IV. The AUC were linearly correlated to doses. Recoveries of AGS-IV in bile, urine and feces were also analyzed following i.v. dose of 2 mg/kg. Cumulative recovery of AGS-IV in bile reached 30.8% in 24h. Cumulative recovery of AGS-IV in urine and feces was 52.14%, which indicates that about 50% of AGS-IV was metabolized in vivo. The bioavailability of AGS-IV after p.o. administration was found to be 3.66%. These findings provide useful information for the research and development of AGS-IV and other potential agents.

Administration, Oral↗
PubMedDate not supplied

sigma54-dependent transcription of the Pseudomonas putida xylS operon is influenced by the IIANtr protein of the phosphotransferase system in Escherichia coli.

IIANtr, encoded within the rpoN operons of many Gram-negative bacteria, is a homologue of a class of phosphoryl transfer proteins of the phosphoenolpyruvate: sugar phosphotransferase system. We have used a xylS operon-lacZ fusion from the TOL plasmid of Pseudomonas putida to show that IIANtr influences sigma 54-dependent transcription when the xylS operon is expressed in Escherichia coli. Loss of IIANtr influences, but does not abolish cyclic AMP-independent carbon catabolite repression.

Bacterial Proteins↗
PubMedDate not supplied

Granulocyte-macrophage colony-stimulating factor and interleukin-5 concentrations in premature neonates with eosinophilia.

OBJECTIVE: Eosinophilia is common among premature neonates, but little is known about the cytokines responsible for influencing its onset in neonates. In adults and transgenic mice, granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-5 (IL-5) influence the development of eosinophilia. We sought to prospectively determine whether these cytokines correlated with the development of eosinophilia in premature infants. STUDY DESIGN: We measured the absolute eosinophil count (AEC) and serial serum concentrations of GM-CSF and IL-5 in premature neonates with eosinophilia. RESULTS: Among 201 premature neonates, 21 had an eosinophil count of > 700/microliter (occurrence, 10.5%). Of these 21 neonates, 4 had mild (700/microliter to 999/microliter), 13 had moderate (1000/microliter to 2999/microliter), and 4 had severe (> 3000/microliter) eosinophilia. No differences in gestational age or age at onset of eosinophilia were observed between the groups, but the duration of eosinophilia was less with mild than with moderate or severe eosinophilia. A total of 20 of the 21 patients had an infection or necrotizing enterocolitis diagnosed within 48 hours of the onset of eosinophilia. In patients with mild and moderate eosinophilia, serial GM-CSF and IL-5 concentrations were below the lowest enzyme-linked immunosorbent assay standard. There was no correlation between AEC and GM-CSF or IL-5 concentration in these infants. However, in one patient with severe eosinophilia, two distinct elevations in IL-5 were noted (34.6 and 46.0 pg/ml); each peak occurred 7 to 8 days before a peak in eosinophil count. CONCLUSION: Eosinophilia is relatively common, and in those neonates with the highest AECs, the duration of eosinophilia can last for > 6 weeks. The majority of cases of eosinophilia occurred in temporal proximity to an infectious illness or necrotizing enterocolitis. Serum concentrations of IL-5 were elevated in only one of our patients with severe eosinophilia.

Biomarkers↗
PubMedDate not supplied

Occurrence and temporal variation in matrix metalloproteinases and their inhibitors during murine secondary palatal morphogenesis.

Extracellular matrix (ECM) molecules are known to play a pivotal role in morphogenesis of the secondary palate, and changes in their composition and distribution, not attributable to changes in synthesis, are known to occur during palatogenesis. The present study was undertaken to determine if the enzymes responsible for mediating their degradation, the matrix metalloproteinases (MMP), and their specific inhibitors, the tissue inhibitors of metalloproteinases (TIMP), are temporospatially regulated during murine palatal shelf morphogenesis. Palatal shelves were harvested at gestational days (gd) 12, 13 and 14. MMPs were identified by gelatin zymography, with and without inhibitors, and the identity of specific bands confirmed by Western blot analysis. TIMPs were identified by reverse zymography. MMP and TIMP messages were detected using RT-PCR with specific primers to MMPs 2, 3, 7, 9 and 13 and TIMPs 1 and 2. Zymography revealed bands of molecular weights corresponding to MMPs 2, 7, 9 and 13 at all ages examined; the intensity of these bands increased with developmental age. Western blot analysis established the presence of MMP-3 and its developmental variation in expression. RT-PCR demonstrated the presence of mRNA for all MMPs and TIMP at all sampling times and all but MMP-2 showed developmental variation. Whereas increases in mRNA were detected for MMPs 3, 9, and 13, MMP-7 mRNA decreased between gd 12 and 14. The results of this study demonstrate that MMPs 2, 3, 7, 9 and 13 and TIMPs 1 and 2 and their messages are present during the course of palatal shelf remodelling and that their expression is temporally regulated.

Animals↗