CAP18 (an 18-kDa cationic antimicrobial protein) is a granulocyte-derived protein that can bind lipopolysaccharide (LPS) and inhibit various activities of LPS in vitro. The present study examined the protective effect of a synthetic 27-amino-acid peptide (CAP18 109-135 ) from the LPS-binding domain of CAP18 against antibiotic-induced endotoxin shock, using highly LPS-sensitive D-(؉)-galactosamine (D-GalN)-sensitized C3H/HeN mice. The antibiotic-induced endotoxin (CAZ-endotoxin) was prepared from the culture filtrate of Pseudomonas aeruginosa PAO1 exposed to ceftazidime (CAZ). Injection of CAP18 109-135 protected the mice injected with LPS or CAZ-endotoxin from death and lowered their tumor necrosis factor (TNF) levels in serum in a dosedependent manner. Treatment with CAZ caused death of the D-GalN-sensitized P. aeruginosa PAO-infected mice within 48 h, while injection with CAP18 109-135 rescued the mice from death. In the mice rescued from death by injection with CAP18 109-135 , endotoxin levels in plasma and TNF production by liver tissues were decreased but the numbers of viable infecting bacteria in their blood were not decreased significantly and remained at the levels in CAZ-treated mice. These results indicate that CAP18 109-135 is capable of preventing antibiotic-induced endotoxic shock in mice with septicemia and that the effect is due to its LPS-neutralizing activity rather than to its antibacterial activity.

We propose that the use of PCR for detection of P. carinii using induced sputum is a useful and non-invasive method that has high sensitivity and specificity for the early diagnosis of PCP.

A DNA nano-tweezer (DNA-NT) structure-based target mRNA detection probe, which uses fluorescence resonance energy transfer (FRET) as a detection signal and works as a single molecule, has been developed. This FRET-paired fluorescent dye-modified DNA-NT, self-assembled from three single-stranded DNAs, alters its structure from open to closed states and produces a FRET signal in response to in vitro transcripts of Hes-1 mRNA. Our results showed that the FRET-based DNA-NT detected both GLUT1 mRNA as a pre-fixed target mRNA model and Hes-1 mRNA as a model expressed inside a living cell. These results confirm the feasibility of using the FRET-based DNA-NT for imaging analysis of target mRNA.

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