Clinical features of children with colorectal polyps and the efficacy of endoscopic treatment: an analysis of 1 351 cases / 中国当代儿科杂志

OBJECTIVES@#To study the clinical features of children with colorectal polyps and the efficacy of endoscopic treatment.@*METHODS@#A retrospective analysis was performed on the medical data of 1 351 children with colorectal polyps who were admitted and received colonoscopy and treatment in the past 8 years, including clinical features and the pattern and outcomes of endoscopic treatment.@*RESULTS@#Among the 1 351 children, 893 (66.10%) were boys and 981 (72.61%) had an age of 2-<7 years, and hematochezia (1 307, 96.74%) was the most common clinical manifestation. Of all the children, 89.27% (1 206/1 351) had solitary polyps, and 95.77% (1 290/1 347) had juvenile polyps. The polyps were removed by electric cauterization with hot biopsy forceps (6 cases) or high-frequency electrotomy and electrocoagulation after snare ligation (1 345 cases). A total of 1 758 polyps were resected, among which 1 593 (90.61%) were pedunculated and 1 349 (76.73%) had a diameter of <2 cm. Postoperative complications included bleeding in 51 children (3.77%), vomiting in 87 children (6.44%), abdominal pain in 14 children (1.04%), and fever in 39 children (2.89%), while no perforation was observed. The children aged <3 years had the highest incidence rates of postoperative bleeding and fever (P<0.0125), and the children with a polyp diameter of ≥2 cm had significantly higher incidence rates of postoperative bleeding, vomiting, and fever (P<0.05).@*CONCLUSIONS@#Solitary polyps, pedunculated polyps, and juvenile polyps are common types of pediatric colorectal polyps. Electric cauterization with hot biopsy forceps or high-frequency electrotomy and electrocoagulation after snare ligation can effectively remove colorectal polyps in children, with good efficacy and few complications. Younger age and larger polyp diameter are associated with a higher risk of postoperative bleeding.

Development of Quantum Dot Submicrobeads-based Fluorescent Immunochromatographic Test Strip for Rapid Detection of Chloramphenicol / 分析化学

A fluorescent immunochromatographic test strip based on the quantum dots submicrobeads (QBs) was developed for quantitative detection of chloramphenicol (CAP). In this method, monoclonal antibody of CAP and OBs complex fluorescent probe was first prepared using 1-ethyl-3-( 3-dimethylaminopropyl ) carbodiimide / N-hydroxysuccinimide coupling approach, then complete antigen CAP-HS-BSA was synthesized and sprayed on nitrocellulose membrane as test line (T line). Similarly, goat anti-mouse antibody was sprayed as control line (C line). The time required for the analysis was 15 min, and the limit of detection (LOD) for CAP was 0. 1 μg / L, with a working range of 0. 1 - 100 μg / L. In spiked milk samples, the test strip demonstrated high recoveries in the range from 93. 3% to 97. 9% with relative standard deviations of less than 7% .

Preliminary study on in-vitro induction of antibiotic resistance in Helicobacter pylori strains isolated from children / 中华儿科杂志

<p><b>OBJECTIVE</b>Many clinical studies indicated that Helicobacter pylori (Hp) strains rarely acquired resistance to amoxicillin but easily to clarithromycin and metronidazole. However, it was unclear whether the antibiotic resistance of Hp strains was induced or passively selected during long-term or frequent treatment with metronidazole, clarithromycin and amoxicillin. To compare the propensity of acquired resistance to antibiotics, Hp strains were exposed to amoxicillin, clarithromycin and metronidazole in vitro in this study.</p><p><b>METHODS</b>All Hp strains were clinical isolates, derived from biopsy specimens of patients taken during endoscopy in the Affiliated Children's Hospital, Zhejiang University School of Medicine from December 2004 to July 2005. To seek susceptible strains, the minimum inhibitory concentrations (MICs) of the three antibiotics were determined by using Epsilometer test (E-test) method. In vitro induction was carried out on serially doubling concentrations of antibiotics incorporated into agar. Isolates were also transferred at least three times on antimicrobial agent-free medium, followed by a redetermination of the final MICs to assess the stability of the selected resistance.</p><p><b>RESULTS</b>7 strains were exposed to antibiotics in vitro. After 6 - 17 passages on antibiotic plates, 7 and 3 strains respectively acquired resistance to metronidazole and clarithromycin, while none of the strains were resistant to amoxicillin. The inductive folds were different among three groups: 8 - 128 folds in metronidazole group; 1 - 256 folds in clarithromycin group; 2 - 16 folds in amoxicillin group. After three transfers on antimicrobial agent-free medium, the MICs decreased significantly in amoxicillin group (P < 0.05) but had no change in metronidazole group and clarithromycin group (P > 0.05).</p><p><b>CONCLUSIONS</b>The metronidazole resistance in Hp was easily selected. Strains resistant to clarithromycin could be selected, but the amoxicillin resistance could not be selected after in vitro induction for Hp isolated from children. The correlation between in vitro and in vivo outcomes suggests that acquired resistance was the main cause for the resistance in Hp strains. The laboratory results of in vitro antibiotic induction could help predict the actual rate of resistance and select appropriate antibiotics for treatment.</p>

Prevalence of resistance to metronidazole in Helicobacter pylori from children and induction of resistance in vitro / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate the prevalence of resistance of Helicobacter pylori (H. pylori) to metronidazole (MTZ) and the distribution change of minimal inhibitory concentrations (MICs) in H. pylori from local children, evaluate the applicability of E-test for MIC determination, and display the propensity of acquired-resistance to MTZ after induction of resistance in vitro.</p><p><b>METHODS</b>One group of 44 H. pylori isolates obtained from Oct. 2002 to Nov. 2003 and another 83 H. pylori isolates obtained from Dec. 2004 to Jul. 2005 from the local children who underwent gastroscopy in the Children's Hospital affiliated to Zhejiang University Medical School and were diagnosed as H. pylori-associated gastritis or peptic ulcer were studied. Susceptibility was tested by agar dilution method or E-test method. In 11 randomly selected metronidazole-sensitive isolates (MTZ(S)), resistance was induced in vitro with MTZ.</p><p><b>RESULTS</b>The resistance rate was 31.8% (14/44) in the 44-islates obtained from Oct. 2002 to Nov. 2003 and 51.8% (43/83) (chi(2) = 4.64, P < 0.05) in 83-isolates obtained from Dec. 2004 to Jul. 2005, respectively. The distribution of MICs were < 0.125 - 128 mg/L and 0.25- > 256 mg/L, in which, the MIC(50) was 0.5 mg/L and 16 mg/L, the MIC(90) was 128 mg/L, respectively. Comparing to agar dilution method which is recommended by National Committee for Clinical Laboratory Standards (NCCLS) for MIC, E-test was significantly associated with agar dilution method (chi(2) = 32.38, P < 0.001). The sensitivity, specificity, agreement rate of E-test were 73.08%, 100%, 87.27%, respectively, while there were factors of 2(2) to 2(6) difference in MICs between the results obtained by E-test and agar dilution. For all the 11 MTZ(S) isolates inducted resistance in vitro with MTZ, 16 MICs were achieved through 7 - 9 (7.2 +/- 0.6) passages of induction in vitro, and 100% acquired-resistance to MTZ through 8 - 10 generations; as a result, 10 of 11 MTZ(S) isolates achieved stable high-level resistance (256 mg/L for 2 and > 256 mg/L for 8) and 1 stable 64 mg/L resistance to MTZ.</p><p><b>CONCLUSIONS</b>The prevalence of resistance to MTZ seems to be increasing in H. pylori from local children. To avoid missed diagnosis of H. pylori resistant to MTZ (MTZ(R)), agar dilution method was needed when detecting susceptibility of H. pylori to MTZ. Resistance to MTZ of H. pylori from children is readily induced in vitro.</p>