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Biomedical subjects

You-ning Liu

Publications and source records attributed to You-ning Liu.

At least 37 records · Page 2Linked to original sources
PubMed2004

[A new member of CMY type cephalosporinase prevailing in Escherichia coli].

OBJECTIVE: To study the resistant phenotype and molecular biology character of plasmid mediated high AmpC-producing clinical isolates of Escherichia coli and to find new AmpC genotype. METHODS: The cefoxitin highly resistant clinical isolates of Escherichia coli were studied by K-B method, three-dimensional method, Isoelectric Focusing (IEF) and the MIC of these strains were examined by micro-dilution method. The conjugation experiment, multiplex PCR and DNA sequencing methods were used in further study. RESULTS: Above 719 strains studied, there are 6 isolates were showed as high AmpC-producing by three-dimensional method and IEF found they could produce a beta-Lactamase which PI was 8.9 and could be inhibited by cloxacillin but not by clavulnate. The strains were resistant to most of third generation cephalosporins, but were susceptible to cefepime, meropenem and imipenem. The experiment also showed that the gene which express this AmpC like beta-Lactamase could be transferable. Multiplex PCR indicated they belong to Citrobacter freundii family. Sequencing of corresponding DNA revealed 99% identities of the deduced amino acid sequence with CMY-2 and CMY-7 respectively. It is a new CMY type cephalosporinase. CONCLUSION: A new CMY type cephalosporinase has been found in clinical strains of Escherichia coli in our hospital. It was resistant to many antibiotics and its resistance could be transferred horizontally.

Bacterial Proteins↗
PubMed2004

[Effects of prone position ventilation on inflammatory factors in blood and bronchial alveolar lavage fluid of acute respiratory distress syndrome dogs caused by pulmonary and extrapulmonary insults].

OBJECTIVE: To observe the changes of inflammatory factors in blood and bronchial alveolar lavage fluid (BALF) of different lung areas of acute respiratory distress syndrome (ARDS) dogs caused by pulmonary and extra-pulmonary causes with low tidal volume and positive end expiratory pressure (PEEP) treatment under prone position ventilation. METHODS: 24 male mongrel dogs were randomly divided into 4 equal groups:ARDSp (ARDS caused by pulmonary causes) experimental group, ARDSp control group, ARDSexp (ARDS caused by extra-pulmonary causes) experimental group, and ARDSexp control group. The ARDSp dogs inspired detergent to cause lung injury, and the ARDSexp dogs were injected with oleic acid through central vein. The results of TNF-alpha, IL-1beta, and IL-6 of blood and BALF in different areas of dog's lung (upper lobe, heart lobe, and diaphragm lobe) and arterial blood gas under lung protective ventilation treatment were measured. RESULTS: After lung injury, the arterial oxygenation index as decreased, and the values of TNF-alpha, IL-1beta, and IL-6 in plasma were obviously getting higher in all groups. The values of inflammatory factors in the BALF from upper lobe and heart lobe of ARDSp dogs were significantly higher than those of the ARDSexp dogs. After receiving low tidal volume and PEEP ventilation under prone position, all dogs were gradually getting ameliorated. CONCLUSION: There are statistically those of the differences in inflammatory factor releasing in different lung areas between the ARDSp dogs and ARDSexp dogs, and low tidal volume and PEEP treatment under prone position ventilation shows good effects both on ARDSexp dogs and ARDSp dogs.

Animals↗
PubMed2004

[Comparative study of clinical characteristics and prognosis of clinically diagnosed SARS patients with positive and negative serum SARS coronavirus-specific antibodies test].

OBJECTIVE: To investigate clinical characteristics and long-term effects of SARS. METHODS: Clinical characteristics of 197 SARS patients in Xiao Tang-shan hospital were analyzed retrospectively, and prognosis of them were analyzed prospectively. RESULTS: Among the 197 patients, 153 patients (77.7%) have positive results of serum SARS coronavirus-specific antibodies test, and 44 patients (22.3%) have negative results. The average age of SARS and non-SARS patients were (40 +/- 12) and (31 +/- 12) years, male/female ratio were 1.0:1.6 and 2.1:1.0, average body temperature were (38.5 degrees C +/- 0.3 degrees C) and (38.1 degrees C +/- 0.4 degrees C), median of fever length were 7.0 d (0.4 approximately 50 d) and 2.3 d (0.3 approximately 37 d) respectively. The occurrence of dyspnea, malaise and gastrointestinal symptom were more often in SARS patient than in non-SARS patients. Some patients have residual symptoms (such as cough, fatigue, dyspnea, abnormality of liver function, hyperglycemia and hyperglyceridemia), and only few patients have lung fibrosis. CONCLUSION: Some patients with other respiratory diseases were misdiagnosed as SARS. There were several obvious differences of clinical characteristics between SARS patient and non-SARS patients. Prognosis of most patients were preciously well, and few still had abnormality of lung function. Residual symptoms of SARS and side effects of drugs used to treat SARS should be discriminated.

Adolescent↗
PubMed2004

[Prevalence of atypical pathogens in adult patients with community-acquired pneumonia in Beijing].

OBJECTIVE: To study the pathogens in community-acquired pneumonia (CAP), especially the prevalence of atypical pathogens. METHODS: A prospective study was performed on 103 consecutive adult patients with CAP between November 2001 and June 2002. Antibodies of the paired serum samples to Mycoplasma pneumoniae, Legionella pneumophilia, and Chlamydia pneumoniae were detected. The P1 adhesion gene of Mycoplasma pneumoniae and the 16S ribosome gene specific for Chlamydia pneumoniae were detected with polymerase chain reaction (PCR). Legionella antigen in urine was detected using enzyme immunoassay (EIA) method. Sputum samples were collected for culture, and bacteria were isolated and identified using conventional methods. RESULTS: The etiology of CAP was identified in 50 (48.5%) patients. The distribution of causal agents was as follows: Mycoplasma pneumoniae in 23 (22.3%) cases, Legionella pneumophilia 3 (2.9%), Chlamydia pneumoniae 2 (1.9%), streptococcus pneumoniae 12 (11.7%), Haemophilus influenzae 9 (8.7%), and Klebsiella pneumoniae 7(6.8%). In 6 patients (5.8%) more than one causal agent were found, among them Mycoplasma pneumoniae was found in 5 cases with mixed infections. CONCLUSIONS: Atypical pathogens especially Mycoplasma pneumoniae have an important role in CAP. Streptococcus pneumoniae and Haemophilus influenzae remain the most common bacteria, and mixed infection should not be ignored.

Adolescent↗
PubMed2004

[Prognostic analysis of lung function and chest X-ray changes of 258 patients with severe acute respiratory syndrome in rehabilitation after discharge].

OBJECTIVE: To analyze the clinical characteristics and prognostic changes of rehabilitating severe acute respiratory syndrome (SARS) patients through regular lung function tests and lung imaging studies after discharge and to retrospectively analyze the treatment data of these patients. METHODS: 258 discharged SARS patients received regular SARS-Co virus IgG test, lung function test and chest X-ray and/or high resolution computerized tomography (HRCT) examination at General Hospital of PLA two months after discharge, and the treatment data of these patients were retrospectively analyzed. RESULTS: 80.6% patients (208 of 258 patients) were positive for SARS-Co virus IgG. 21.3% patients (55 of 258 patients) showed lung diffusion abnormity (D(LCO) < 80%pred). Compared to 155 SARS-Co virus IgG positive patients without lung diffusion abnormity and 50 SARS-Co virus IgG negative patients, the 53 SARS-Co virus IgG positive patients with lung diffusion abnormity had longer fever course, higher dosages of glucocorticoid therapy, higher percentage of oxygen therapy and non-invasive ventilation. 51 of the 53 patients with lung diffusion abnormity received lung function test after one month, and the results of D(LCO) improved in 80.4% patients (41 of 51 patients). 40 of 51 patients with lung diffusion abnormity showed lung fibrosis, and the fibrosis decreased in 55% patients (22 of 40 patients) after one month. CONCLUSIONS: This finding suggests that lung fibrosis caused by SARS mostly occurs in severe patients, and it can resolve spontaneously. D(LCO) may be more sensitive than HRCT in evaluating the fibrotic changes.

Adolescent↗
PubMed2004

[Effects of lung protective ventilation on inhibiting inflammatory mediators released into plasma and bronchial alveolar lavage fluid in acute respiratory distress syndrome caused by pulmonary and extrapulmonary insults in dog].

OBJECTIVE: To observe the changes in oxygenation index and inflammatory mediators in plasma and bronchial alveolar lavage fluid (BALF) of different lung areas (upper lobe, heart lobe, diaphragm lobe) in acute respiratory distress syndrome (ARDS) caused by pulmonary and extra-pulmonary insults with lung protective ventilation treatment in dog. METHODS: Twenty-four male mongrel dogs were randomly divided into ARDSp (ARDS caused by pulmonary disease) experimental group, ARDSp control group, ARDSexp (ARDS caused by extra-pulmonary disease) experimental group, and ARDSexp control group. In ARDSp dogs detergent was introduced intratracheally to cause lung injury, while in ARDSexp dog's oleic acid was given intravenously to produce lung injury. After lung injury, the dogs in the experimental groups received lung protective ventilation treatment (tidal volume: 8 ml/kg, positive end-expiratory pressure (PEEP): 10 cm H2O (1 cm H2O=0.098 kPa)), and the control groups received large tidal volume ventilation (tidal volume: 14-17 ml/kg, PEEP: 0). The contents of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL- 1beta), IL-6 in plasma and BALF from different areas of dog's lung (upper lobe, heart lobe, and diaphragm lobe), and arterial blood gas under lung protective ventilation treatment were measured. RESULTS: After lung injury, the results of arterial oxygenation index were getting worse, and the contents of TNF-alpha, IL-1beta, and IL-6 in plasma were obviously elevated. The contents of inflammatory mediators in upper lobe and heart lobe of ARDSp dogs were higher than that of ARDSexp dogs (all P<0.05). After receiving lung protective ventilation, the symptoms in the dogs of experimental groups were gradually getting ameliorated compared to control groups, but ARDSexp experimental dogs rallied better than ARDSp experimental dogs. CONCLUSION: There are statistical differences in the amount of inflammatory mediators released in BALF from different lung areas and arterial oxygenation amelioration between ARDSp dogs and ARDSexp dogs, and better effects are seen in ARDSexp dogs than ARDSp dogs under lung protective ventilation treatment.

Animals↗
PubMed2004

[The phenotype and genotype patterns of erythromycin-resistant Streptococcus pneumoniae].

OBJECTIVE: To investigate the resistance phenotypes and genotypes in erythromycin-resistant Streptococcus (S.) pneumoniae. METHODS: The minimum inhibitory concentration (MIC) of erythromycin, clindamycin, penicillin and fluoroquinolones against 192 strains of S. pneumoniae was tested with broth microdilution method according to the guidelines of the National Committee for Clinical Laboratory Standards. Of 148 clinical isolates of erythromycin resistant S. pneumoniae, the macrolide resistance phenotypes were observed by the erythromycin-clindamycin-spiramycin triple-disc test and erythromycin resistance genes were detected by polymerase chain reaction. RESULTS: 42.7% S. pneumoniae isolates was resistant (intermediate and resistant) to penicillin while the resistance rates to erythromycin and clindamycin were 77.6% and 66.7% respectively. The ermB gene, being the most prevalent, was detected in 79.1% of the 148 erythromycin-resistant strains. The main phenotype (85.1%) of erythromycin-resistant strains was constitutive macrolide, lincosamide, and streptogramin B resistance phenotype (cMLS). Erythromycin MICs for S. pneumoniae ermB-positive isolates were higher than those for mefA-positive isolates. 74.4% of the ermB-positive isolates demonstrated erythromycin MICs of > 16.0 micro g/ml, and the erythromycin MICs for mefA-positive isolates ranged from 0.5 approximately 4.0 micro g/ml. CONCLUSIONS: The resistance rate of S. pneumoniae to erythromycin is high in China. The main phenotype is cMLS. Ribosomal modification (ermB gene coded) is the main resistance mechanism against erythromycin in S. pneumoniae

Anti-Bacterial Agents↗
PubMed2004

[Inspiration from diffuse panbronchiolitis].

Diffuse panbronchiolitis is a new respiratory tract disease and was initially found in Japan. Strong association between race-dependent antigens and diffuse panbronchiolitis suggests a genetic predisposition to the disease. 14-member ring and 15-member ring macrolides have been proved to have significant therapeutical effect on diffuse panbronchiolitis. The discovery of diffuse panbronchiolitis and the advent of macrolide therapy for this disease suggests that clinicians should pay more attention to racial difference of some diseases and never overlook any accidental phenomenon in clinical practice.

Bronchiolitis↗
PubMed2004

[The changes in effective local blood perfusion and compensatory ventilation in different lung areas of acute respiratory distress syndrome rabbits model].

OBJECTIVE: To discuss the mechanism of severe hypoxemia that induced with acute respiratory distress syndrome (ARDS) by way of observing the effective local blood perfusion in different lung areas of ARDS rabbits. METHODS: ARDS rabbit models were established by injecting oleic acid through central vein, and the results of effective local blood perfusion in different areas of rabbit lung (upper area, abdominal area, and dorsal area of right lung)with PIM-II laser perfusion imager and arterial blood gas under different ventilation modes [large tidal volume ventilation, low tidal volume ventilation + positive end-expiratory pressure (PEEP), prone position + large tidal volume ventilation, and prone position + low tidal volume ventilation + PEEP] were measured. RESULTS: The results of oxygenation index were significantly getting worsen after lung injury, and after receiving lung protective ventilation (including low tidal volume + PEEP, prone position + low tidal volume + PEEP), the indexes were taking a turn to the better. After lung injury, the results of effective local lung blood perfusion index (including upper area, abdominal area, and dorsal area) under right lung of ARDS rabbits decreased in the experimental ARDS groups. The results of experimental dorsal area group decreased most significantly, and the results of experimental upper area group changed most lightly. We observed that the effects of receiving low tidal volume + PEEP ventilation were not as good as prone position + low tidal volume + PEEP ventilation in the dorsal area of the rabbit lung compared to the results of effective local area lung blood perfusion index between two ventilation modes, there showed significantly differences in statistics. CONCLUSION: We indicated that the one of the main mechanisms of severe hypoxemia in ARDS might be caught by the shunt between pulmonary artery and pulmonary vein just like physiological right to left shunt, which caused severe ventilation/perfusion disturbance. Both low tidal volume ventilation + PEEP and prone position + low tidal volume ventilation + PEEP had good effects on ameliorating local blood perfusion, and the effects of ventilation mode of prone position + low tidal volume ventilation +PEEP might be better.

Animals↗
PubMed2003

[Immediate intraoral adaptation of mandibular advancing appliances of thermoplastic material for the treatment of obstructive sleep apnea-hypopnea syndrome].

OBJECTIVE: To appraise the effect of immediate intraoral adaptation of mandibular advancing appliances (MAA) consisting of thermoplastic material for the treatment of obstructive sleep apnea-hypopnea syndrome (OSAHS). METHODS: 45 patients with OSAHS was treated with MAA that was directly moulded intraorally before sleep. Polysomnography (PSG) was performed and questionnaires recorded prior to and 4 weeks after treatment with MAA. RESULTS: The efficiency of MAA for OSAHS was 82%. The medial apnea-hypopnoea index decreased from 38 +/- 22 to 11 +/- 9 events per hour (P < 0.001); the medial duration of apnea decreased from 22 +/- 8 to 15 +/- 11 second (P < 0.001); the minimum SaO(2) increased from (72 +/- 11)% to (83 +/- 9)% (P < 0.001), and the medial snore index decreased from 304 +/- 105 to 108 +/- 113 events per hour (P < 0.001). The patients' daytime sleepiness was alleviated, and the majority of the patients could acclimatize themselves to MAA in 3 to 7 days. CONCLUSIONS: The MAA consisting of thermoplastic material improved OSAHS. It is immediately adaptable and less expensive, and should be considered as a feasible medical treatment.

Activator Appliances↗