LPS induced PCT production via TLR-4/NF-кB passway:it is the difference of G-/G+ bacteremia rats.

Sepsis by Gram-negative bacteria infection leads to further increase in procalcitonin (PCT). Herein, we examined the expression of PCT after 24 h in rats by injecting Escherichia coli (E. coli) or Staphylococcus aureus (SA). Healthy male SD rats were divided into six groups (n = 8): (1) Control group: no treatment; (2) SA group: injected with 106CFU/ml SA suspension 0.1 ml in the tail vein; (3) SA and antibiotics group: injected with 106/ml SA bacterial suspension 0.1 ml and 4 mg/kg Cefotaxime sodium, q8h in the tail vein; (4) E. coli group: injected with 106CFU/ml E. coli suspension 0.1 ml in the tail vein; (5) E. coli and antibiotics group: injected with 106/ml E. coli bacterial suspension 0.1 ml and 4 mg/kg Cefotaxime sodium, q8h in the tail vein; and (6) Endotoxin group: injected with 5 mg/kg endotoxin in the tail vein. Expression of PCT was significantly increased in the E. coli, SA or endotoxin-induced bacteremia rats than in the control rats. Compared with SA, PCT was more significantly increased in E. coli rats. NF-κB changes were in line with PCT. Next, we investigated whether the expression of PCT decreased when TLR4 or NF-κB were inhibited after injecting E. coli in rats. A total of 40 healthy male SD rats were divided into five groups (n = 8): (1) Control group: no treatment; (2) E. coli group: injected with 106CFU/ml E. coli suspension 0.1 ml in the tail vein. (3) E. coli and PBS group: injected with 106CFU/ml E. coli suspension 0.1 ml and PBS 0.1 ml in the tail vein. (4) E. coli and TAK242: injected with 106CFU/ml E. coli suspension 0.1 ml and 3 mg/kg TAK242 in the tail vein. (5) E. coli and BAY-11-7082: injected with 106/ml E. coli suspension 0.1 ml and 25 mg/kg BAY-11-7082 in the tail vein. A marked increase of TLR4, NF-κB, LPS and PCT expression was observed in the lungs after E. coli induced bacteremia. Expressions of TLR4, NF-κB, and PCT proteins were decreased in the lungs at 24 h after injection of TAK-242 or BAY-11-7082. In summary, this study suggested that LPS is the key factor for differential expression of PCT between E. coli and SA bacteremia. E. coli induces PCT elevation via the TLR4/NF-κB pathway.

Application of genome-wide microarray for screening genes related to peritoneal metastasis of colorectal cancer / 南方医科大学学报

<p><b>OBJECTIVE</b>To screen genes related to peritoneal metastasis of colorectal cancer.</p><p><b>METHODS</b>Specimens of primary cancer and normal mucosa tissues were collected from 3 patients with peritoneal metastasis of colorectal cancer. The total RNA were extracted and inversely transcribed into cDNA to synthesize aRNA using in vitro RNA synthesis. The synthesized aRNA, after labeling with Cy3, were hybridized with the whole human genome oligo microarray. The Empirical Bayes method was used to screen the differentially expressed genes, followed by confirmation of the selected genes by semi-quantitative RT-PCR.</p><p><b>RESULTS</b>With a threshold of P≤0.05, a total of 105 differentially expressed genes were identified in primary cancer lesions, including 42 up-regulated and 63 down-regulated genes. Three of the up-regulated genes (S100P, PRDX1 and SLPI) were selected and confirmed by RT-PCR, which yielded results consistent with those from gene microarray.</p><p><b>CONCLUSION</b>Gene microarray technique can provide valuable clues for locating the tumor markers of peritoneal metastasis in colorectal cancer patients.</p>