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Objective To explore the effect and its possible mechanism of human umbilical cord mesenchymal stem cells (hUCMSCs) on bacterial growth in bronchoalveolar lavage fluid (BALF) of newborns with ventilator associated pneumonia (VAP).Methods Newborns admitted to neonatal intensive care unit (NICU) in Guangdong Women and Children Hospital Affiliated to Guangzhou Medical University from June 1,2012 to December 31,2012 were reviewed.The inclusion criteria were:(1)Positive BALF culture results.(2) Requirement of mechanical ventilation with tracheal intubation.(3) Diagnosed as ventilator-associated pneumonia.Two pieces of BALF samples of newborn were collected and randornaly divided into experimental and control group.hUCMSCs were added into the experimental group,while the same volume of conditioned medium was added into the control group.Both groups were incubated for six hours in humidified CO2 incubator at 37 ℃,then,bacterial growth was assessed by colony forming unit (CFU) counts.Levels of the antimicrobial peptides (Cathelicidin/LL-37 and human HBD-2) were determined by enzyme-linked immunosorbent assay and Western blot.Paired t-test was used for statistical analysis.Results Among the culture results of 31 newborns,there were Klebsiella pneumoniae (6 cases,19.3％),Stenotrophomonas narrow food aeromonas (6 cases,19.3％),Hemolytic staphylococci (5 cases,16.1％),Escherichia coli (3 cases,9.7％),Bacterial meningitis septicemia Elizabeth Platinum (3 cases,9.7％),Acinetobacter baumannii (3 cases,9.7％),Pseudomonas putida (2 cases,6.4％),Pseudomonas aeruginosa (1 case,3.2％),Staphylococcus aureus (1 case,3.2％) and Enterobacter cloacae (1 ease,3.2％).The CFU counts in experimental group were much less than those in control group [(2.60±0.67) ×104] CFU/ml vs [(1.18±0.32) ×105] CFU/ml,(t=-20.19,P＜0.01).Levels of Cathelicidin/LL-37 and HBD-2 in experimental group were higher than those in control group [Cathelicidin/LL-37:(8.98 ± 3.22) ng/ml vs (3.18 ± 1.57) ng/ml,t =17.79,P ＜ 0.01 ;HBD-2:(379.87±11.74) pg/ml vs (39.89±2.86) pg/ml,t=37.62,P＜0.01].Conclusions hUCMSCs had antimicrobial effect on bacterial growth in BALFs from ventilator associated pneumonia possibly by the secretion of antimicrobial peptides (Cathelicidin/LL-37 and HBD-2).
RESUMO
AIM: To investigate the distribution in mice and pharmacokinetics in rabbits of fraction Ⅲ isolated from Naja naja atra venom. METHODS: Fraction Ⅲ was labelled with [~(125)Ⅰ] by chloramine-T method. The drug concentration in blood was determined by a radionuclide tracing kinetic methods. The distribution of [~(125)Ⅰ]-fraction Ⅲ in mice was determined based on the ratio of the relative incorporation of radioactivity in tissues to that in blood. RESULTS: In two and four hours after intravenous injection of fraction Ⅲ in mice, the organs in which the ratio of the radioactivity incorporation was bigger than 1 were liver, kidney, lung, heart and muscle, whth the maximun in kidney. After intravenous injection of fraction Ⅲ, with dosages of 75, 150 and 300 ?g/kg, respectively, the T_(1/2)?, T_(1/2)? and T_(1/2)? were 39.6-42.5 min, 16.8-17.3 h and 21.7-22.1 h, respectively. There was no significant difference between the different dosages. CONCLUSION: Fraction Ⅲ was mostly found in kidney, followed by liver and lung after intravenous administration in mice. The pharmacokinetics is in accordance with the feature of three atrioventricular modle. The AUC is in direct proportion to the dosage. It suggests that the distribution and clearance of the drug is a grade 1 linear kinetic process. [