ABSTRACT
Objective: To investigate the characteristics of lower respiratory tract infection caused by Chryseobacterium and its antimicrobial susceptibility in vitro . Methods: The clinical data of 52 cases of lower respiratory tract infection caused by Chryseobacterium were analyzed, and the antimicrobial susceptibility of commonly used agents was determined with the method of agar dilution. Also the 50% lethal dosage (LD 50 ) (as the marker of virulence) of 20 randomly selected Chryseobacterium strains for mice were determined. Results: (1) Thirty six was over 60 years old;all of 52 cases had underlying diseases, mainly were chronic obstruction pulmonary disease and malignant tumors. Seventeen cases had the history of incubation or tracheotomy for mechanical ventilation, and 35 had history of broad antibiotics treatment. The mean hospitalization time before infection were 35.6 d, and 38.5% of the cases had mixed infection with other bacteria. No specific clinical manifestations and chest X ray appearance revealed. (2) The in vitro activity of 25 agents showed that these strains were highly resistant. (3) The range of the LD 50 of tested strains was 4.11?10 6 5.68?10 8/mouse, suggesting low virulence of this kind of bacteria. Conclusion: The lower respiratory tract infection caused by Chryseobacterium has no unique features; the incidence of the infection increases in immunosuppressed old patients with various underlying diseases, although the virulence is relatively low. Because the clinical isolates are highly resistant, the antibiotics should be selected according to the results of bacterial sensitivity test.
ABSTRACT
To study the treatment of metastasis of experimental lung cancer with a recombinant adenovirus carrying IL 2 gene, concentrations of IL 2 and associated cytokines in murine lung lavage and blood were determined by ELISA at different times after intratracheal injection of the recombinant adenovirus. The lung metastasis nodes, survival time, survival rate were investigated in a C57BL/6 mouse model by intratracheal administration, and the NK activity and CTL activity were also determined by 51 Cr 4 hour release method. The results showed that IL 2 could be detected in lung tissue as early as 6 hours after administration of IL 2 gene, its concentration was higher in lung lavage than in peripheral blood, and was higher in experimental group than that in the control group; intratracheal use of the IL 2 carring recombinant adenovirus had significant therapeutic effect on metastasis of experimental lung cancer. Increased CTL and NK activities, longer survival time, and higher survival rate were observed in the experimental group compared with the control group. It is suggested that intratracheal usage of adenovirus vector carrying IL 2 gene might play therapeutic role on the lung cancer metastasis, indicating that gene therapy of lung tumors could be done through airway directly with recombinant adenovirus.
ABSTRACT
Objective:To explore the effect of nontypeable Haemophilus influenzaen(NTHi)strain ATCC49247on pri-mary rabbit tracheal epithelial(TE)cells.Methods:TE cells were isolated with low temperature protease digestion and cul-tured on collagen gel-coated membranes at an air-liquid interface in serum-free medium.Under these conditions,TE cells were proliferated and differentiated into a pseudostratified mucociliary epithelium,which were infected by NTHi.Morphologic changes of the cells were examined by scanning electron microscopy(SEM)and transmission electron microscopy(TEM)after 24h.Results:SEM showed that bacteria adhered to non-ciliated cells;death or apoptosis occurred in90%of TE cells and cil-iaries were broken.TEM showed NTHi adhered to the cell surface on which there were many microvillus.Lamellipodia and microvilli surrounded bacteria within vacuoles of airway cells.Conclusion:NTHi can attach to non-ciliated cells,the latter de-vours the bacteria by lamellipodia and microvilli.NTHi is toxic to TE cells,resulting in the death or apoptosis of TE cells.
ABSTRACT
Objective: To investigate the effect of CpG motif oligodeoxynucleotides (CpG ODN) on the antigen induced allergic airway reaction in mice. Methods: The asthma model was set up in the C57BL/6 mice with OVA, the CpG ODN in the dose of 30 ?g was co administered intraperitoneally with the antigen in sensitization stage to study its effect on the airway allergenic reactions. Results: (1)Compared with the control, coadministration of CpG ODN in sensitization phase significantly inhibited airway eosinophilia after antigen challenge( P