Diagnostic value of volumetric capnography in patients with chronic cough variant asthma

OBJECTIVES: To evaluate the quantitative changes and diagnostic performance of volumetric capnography (VCap) parameters in patients with cough variant asthma. METHODS: This cross-sectional study enrolled 31 patients with cough variant asthma and 30 patients with chronic cough without asthma between November 2010 and March 2012. VCap measurements were recorded at baseline, during the five steps of the histamine challenge, and after bronchodilation with salbutamol. They were then compared between the baseline and histamine challenge, and between the two groups. Receiver operating characteristic curve analysis was performed for different VCap measurements. RESULTS: The slope of phase III (dc/dv3) and the ratio of phase III slope to phase II slope (SR23%) decreased from baseline upon challenge with 1.1 mg histamine in cough variant asthma patients but increased in patients with chronic cough without asthma. Additionally, the change upon challenge with 1.1 mg histamine in dc/dv3 from baseline (S6-S1dc/dv3) in cough variant asthma patients had the largest area under the curve (AUC) (0.814, 95% CI: 0.697-0.931; p<0.001). The AUC for change upon challenge with 1.1 mg histamine in SR23% from baseline was 0.755 (95%CI: 0.632-0.878; p<0.001). At a cutoff of 19.8, S6-S1 dc/dv3 had a sensitivity of 74.2% and specificity of 90.0% and at a cutoff of 40.7, S6-S1 SR23% had a sensitivity of 48.4% and specificity of 96.7%. CONCLUSION: Patients with cough variant asthma exhibit distinct VCap responses for dead space parameters upon challenge with histamine in comparison to patients with chronic cough. VCap parameters like phase III slope and phase III/phase II slope ratio could be used to aid the diagnosis of cough variant asthma.

Screening and identification of CD13-binding peptides with phage display peptide library / 南方医科大学学报

<p><b>OBJECTIVE</b>To screen and identify the peptides that specifically bind to CD13 on monocytes.</p><p><b>METHODS</b>The phages capable of specific binding to CD13 were screened in the phage-displayed 12-peptide library. The affinity of the selected phages with CD13 was verified with enzyme-linked immunosorbent assay (ELISA). The sequences of the peptides bound to the phages were deduced according to the phage DNA sequences, and the functional peptides aligned using the BLASTP on the Website NCBI were synthesized. To analyze the biological function of the screened peptides, the location of the peptides bound to THP-1 cells was detected using immunofluorescence assay. The blocking effect of WM15 on the peptide binding to THP-1 cells was assessed by immunofluorescence assay.</p><p><b>RESULTS</b>The phages that specifically bound to CD13 were effectively enriched to approach saturation after 4 rounds of panning. The recovery rate in the fourth round was 30 times that in the first round. Twenty selected phages were verified by ELISA, and the signals of 10 phages were higher than the control. The sequences of the peptides P9 and P7 showed 83% and 100% identity with those of human cytomegalovirus (HCMV) UL38 and UL105, respectively. The peptides bound to the cell membrane of THP-1 cells as shown by immunofluorescence assay. The binding of the peptides P9 and P7 to THP-1 cells was blocked by CD13-specific monoclonal antibody WM15 at different levels.</p><p><b>CONCLUSION</b>Two peptides (P7 and P9) that can specifically bind to CD13 have been screened successfully, and these two peptides show specific binding to CD13 on the membrane of THP-1 cells.</p>