[Correlation between serum uric acid levels and obstructive sleep apnea/hypopnea syndrome in children].

OBJECTIVE: To explore the level of serum uric acid (UA) in children with obstructive sleep apnea/hypopnea syndrome (OSAHS). METHOD: Between Sep. 2008 and Mar. 2010, 138 children with OSAHS were enrolled in study group. Sixty-five children with accessory auricle or ptosis of upper lid were enrolled into the control group. Furthermore, according to apnea/hypopnea index (AHI) or obstructive apnea index (OAI) the study group was further divided into three subgroups (mild, moderate and severe group). At last, the study group and control group were divided into two groups according to the body mass index (BMI), separately. The fasting serum UA level was compared among the different groups. Then the correlation between the serum UA level and AHI, BMI, oxygen desaturation index, least arterial oxygen saturation (LSaO(2)) and the percentage of total sleep time with arterial oxygen saturation < 0.92 was also analyzed in OSAHS children with or without overweight and obesity respectively. RESULT: The difference of serum UA level between the study group and control group (z = -0.443), and the difference among the three groups (χ(2) = 1.241) was not significant(P > 0.05). The serum UA level in overweight and obese children [study group, 273.0 (238.3 - 357.3); control group, 298.0 (253.0 - 336.0)] was significantly higher than that in children with normal BMI [study group, 246.5(215.8 - 300.0); control group, 266.0 (224.0 - 303.3)] (z = -2.084, -2.214, P < 0.05). That serum UA level did not correlate with the above index of OSAHS was observed in children with or without overweight and obesity in study group (P > 0.05). CONCLUSION: Findings of higher serum UA level were not observed in children with OSAHS. There was no correlation between serum UA level and the above indices of OSAHS. The serum UA level in overweight and obese children was significantly higher than that in children with normal BMI.

[Antimicrobial resistance and penicillin resistance-associated genes of Streptococcus pneumoniae isolated from children with respiratory tract infection].

OBJECTIVE: To investigate the antimicrobial resistance and penicillin resistance-associated genes (TEM and pbp2B) of Streptococcus pneumoniae (S. pneumoniae) isolated from sputum specimens of Guangzhou children with respiratory tract infection. METHODS: E-test and Kirby-Bauer methods were applied to detect the antibiotic susceptibility of 44 strains of S. pneumoniae. PCR was used to detect resistance genes pbp2B and TEM, followed by DNA sequence analysis of pbp2B gene. The sequence results were compared to those of penicillin-susceptible S. pneumoniae R6. RESULTS: Of the 44 isolates of S. pneumoniae, only 5 (11.4%) were susceptible to penicillin. All strains were resistant to erythromycin but susceptible to ofloxacin and vancomycin. The resistance rate of the isolates to clindamycin and trimoxazole was more than 90%. The S. pneumoniae isolates showed a high susceptibility to amoxicillin, imipenem and ceftriaxone, with a resistance rate of 0, 2.6% and 3.9%, respectively. The sequence analysis showed that more than 99% nucleotide sequence of pbp2B gene of five penicillin-susceptible isolates was the same as penicillin-susceptible S. pneumoniae R6, without any amino acid replacement. Site mutation was found in the remaining 39 penicillin-nonsusceptible isolates with a nucleotide mutation rate ranging from 13.2% to 23.1% and amino acid replacement rate from 6.5% to 10.9%. The 39 penicillin-nonsusceptible isolates were classified into 4 types according to the mutation site between Ser391 and Thr492 of pbp2B: type I (n=30), type II (n=7), type III (n=1) and type IV (n=1). No TEM gene was detected in all the 44 S. pneumoniae isolates. CONCLUSIONS: The S.pneumoniae isolates from Guangzhou children with respiratory tract infection are resistant to penicillin and erythromycin. Amoxicillin and the third generation cephalosporin may be recommended for treating S. pneumoniae infection. The mutation of pbp2B gene plays an important role in the development of S. pneumoniae resistance to penicillin.

[Distribution and antibiotic resistance of pathogens isolated from children with infectious diarrhea in Guangzhou].

OBJECTIVE: To study the distribution and antibiotic resistance of the isolated pathogens from children with infectious diarrhea in Guangzhou. METHODS: The fecal samples of 2 409 children with infectious diarrhea between January 2006 and December 2007 were collected and cultured. Pathogenic bacterium were isolated and identified by biochemical and serological methods. The antibiotic susceptibilities were tested by the Kirby-Bauer method. RESULTS: A total of 448 isolates of pathogenic bacterium (18.6%) were obtained, including Shigella (n=159), enteropathogenic Escherichia coli (n=141), Salmonella (n=76), Vibrion (n=11), fungus (n=41), and C jejuni (n=20). All of isolates of the three major pathogenic bacterium, Shigella, enteropathogenic Escherichia coli and Salmonella, were susceptible to imipenem and less than 10% of the isolates were resistant to the third generation cephalosporins and beta-lactamase inhibitors. However, the isolates showed a high resistance to ampicillin and sulfamethoxazole/trimethoprim (>75%). CONCLUSIONS: Shigella, enteropathogenic Escherichia coli and Salmonella were major pathogenic bacterium of diarrhea in children from Guangzhou. The major isolates were susceptible to imipenem, the third generation cephalosporins and beta -lactamase inhibitors, but were resistant to ampicillin and sulfamethoxazole/trimethoprim.

[Effect of small interfering RNA on matrix metalloproteinase-9 expression in vascular endothelial cells stimulated by serum from children with Kawasaki disease].

OBJECTIVE: To investigate the matrix metalloproteinase-9 (MMP-9) expression in vascular endothelial cells stimulated by the serum obtained from children with Kawasaki disease (KD) during the acute phase in the absence and presence of MMP-9 small interfering RNA (siRNA). METHODS: MMP-9 siRNA plasmids were constructed and transduced into vascular endothelial cells (ECV-304) by liposomal transfection. ECV-304 were cultured in 6 different conditional media: KD serum + siRNA negative control, normal serum, KD serum + MMP-9 siRNA1 (pSilencer3.1-MMP1), KD serum + MMP-9 siRNA2 (pSilencer3.1-MMP2), KD serum + gamma-globulin, and KD serum. RT-PCR and Western blot were used to detect MMP-9 expression at mRNA and protein levels in ECV-304. RESULTS: The mRNA and protein expression of MMP-9 in ECV-304 cultured with 10% serum from KD patients (2.49 +/- 0.03, 1.20 +/- 0.04) and KD serum + siRNA negative control plasmid (2.45 +/- 0.03, 1.15 +/- 0.03) were significantly higher than those cultured with 10% serum from normal control children (1.21 +/- 0.03, 0.52 +/- 0.03, respectively; all P < 0.01) and the increased MMP-9 expression could be significantly inhibited by MMP-9 siRNA1, MMP-9 siRNA2 and gamma-globulin (100 mg/ml, all P < 0.01). CONCLUSIONS: The increase of MMP-9 expression in vascular endothelial cells induced by the serum from KD patients might take part in the formation of coronary artery lesions. Two customized MMP-9 siRNA plasmids (pSilencer3.1-MMP1 and pSilencer3.1-MMP2) can significantly inhibit both MMP-9 mRNA and protein expression.

[Detection and analysis of SARS coronavirus-specific antibodies in sera from non-SARS children].

OBJECTIVE: To examine the presence of severe acute respiratory syndrome (SARS) coronavirus-specific antibodies in the sera from non-SARS children. METHODS: Indirect immunofluorescent assay and double-antigen sandwich enzyme-linked immunosorbent assay (ELISA) were used to detect the virus-specific antibodies in sera of 1,060 non-SARS children in Guangzhou. RESULTS: All the serum samples from the 1,060 non-SARS children were negative for both IgG and IgM antibodies against SARS coronavirus as determined by indirect immunofluorescent assay, with only two serum samples showing weak positivity for SARS coronavirus-specific antibodies identified by double-antigen sandwich ELISA. CONCLUSION: No SARS coronavirus-specific antibody are present in the sera of non-SARS children.

[Genotype of human calicivirus from infants with diarrhea in Guangzhou city in 2001].

OBJECTIVE: To understand the characteristics of human calicivirus (HuCV) infection in infants with diarrhea in Guangzhou city and to study genotype of the virus. METHODS: The authors collected fecal specimens from 22 children with acute nonbacterial gastroenteritis from November to December, 2001. HuCV was detected from the specimens by RT-PCR. The PCR products were cloned into the PMD18-T cloning vector and sequenced. RESULTS: HCV was detected from the specimens of 2 cases (9%, 2/22). The nucleotide sequence analysis revealed that the virus strains belonged to genotype 2 of Norwalk-like viruses. CONCLUSION: HuCV is one of the pathogens causing diarrhea in infants and young children in Guangzhou area. HuCV infection occurred sporadically in autumn and winter.