Comparison between high-frequency irreversible electroporation and irreversible electroporation ablation of small swine liver: follow-up of DCE-MRI and pathological observations / 中华医学杂志(英文版)

BACKGROUND@#High-frequency irreversible electroporation (H-FIRE) is a novel, next-generation nanoknife technology with the advantage of relieving irreversible electroporation (IRE)-induced muscle contractions. However, the difference between IRE and H-FIRE with distinct ablation parameters was not clearly defined. This study aimed to compare the efficacy of the two treatments in vivo.@*METHODS@#Ten Bama miniature swine were divided into two group: five in the 1-day group and five in the 7-day group. The efficacy of IRE and H-FIRE ablation was compared by volume transfer constant (Krans), rate constant (Kep) and extravascular extracellular volume fraction (Ve) value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), size of the ablation zone, and histologic analysis. Each animal underwent the IRE and H-FIRE. Temperatures of the electrodes were measured during ablation. DCE-MRI images were obtained 1, 4, and 7 days after ablation in the 7-day group. All animals in the two groups were euthanized 1 day or 7 days after ablation, and subsequently, IRE and H-FIRE treated liver tissues were collected for histological examination. Student's t test or Mann-Whitney U test was applied for comparing any two groups. One-way analysis of variance (ANOVA) test and Welch's ANOVA test followed by Holm-Sidak's multiple comparisons test, one-way ANOVA with repeated measures followed by Bonferroni test, or Kruskal-Wallis H test followed by Dunn's multiple comparison test was used for multiple group comparisons and post hoc analyses. Pearson correlation coefficient test was conducted to analyze the relationship between two variables.@*RESULTS@#Higher Ve was seen in IRE zone than in H-FIRE zone (0.14 ± 0.02 vs. 0.08 ± 0.05, t = 2.408, P = 0.043) on day 4, but no significant difference was seen in Ktrans or Kep between IRE and H-FIRE zones at all time points (all P > 0.05). For IRE zone, the greatest Ktrans was seen on day 7, which was significantly higher than that on day 1 (P = 0.033). The ablation zone size of H-FIRE was significantly larger than IRE 1 day (4.74 ± 0.88 cm2vs. 3.20 ± 0.77 cm2, t = 3.241, P = 0.009) and 4 days (2.22 ± 0.83 cm2vs. 1.30 ± 0.50 cm2, t = 2.343, P = 0.041) after treatment. Apoptotic index (0.05 ± 0.02 vs. 0.73 ± 0.06 vs. 0.68 ± 0.07, F = 241.300, P  0.05). Electrode temperature variations were not significantly different between the two zones (18.00 ± 3.77°C vs. 16.20 ± 7.45°C, t = 0.682, P = 0.504). The Ktrans value (r = 0.940, P = 0.017) and the Kep value (r = 0.895, P = 0.040) of the H-FIRE zone were positively correlated with the number of hepatocytes in the ablation zone.@*CONCLUSIONS@#H-FIRE showed a comparable ablation effect to IRE. DCE-MRI has the potential to monitor the changes of H-FIRE ablation zone.

Drug resistance of methicillin resistant Staphylococcus strains in burn ward and relative analysis / 中华烧伤杂志

<p><b>OBJECTIVE</b>To study the distribution and drug resistance of methicillin resistant Staphylococcus strains in various specimens of inpatients in burn wards, and to provide reference for clinical treatment.</p><p><b>METHODS</b>Bacteria were isolated from specimens of wound exudate, blood, sputum, and bronchoalveolar lavage fluid etc., which were collected from patients hospitalized in our burn wards from January 2008 to December 2010. The bacteria were routinely cultured and identified. Drug resistance of the Staphylococci to 15 antibiotics commonly used in clinic was identified by K-B disk diffusion method. Data were processed with statistical software WHONET 5.5. The homology of 40 strains of methicillin resistant Staphylococcus aureus (MRSA) was analyzed by pulsed-field gel electrophoresis (PFGE).</p><p><b>RESULTS</b>Altogether 386 strains of Staphylococcus were isolated, including 196 strains of Staphylococcus aureus and 190 strains of coagulase negative Staphylococcus. The mean annual isolation rates of MRSA and methicillin resistant coagulase negative Staphylococcus (MRCoNS) were respectively 73.00% (143/196) and 74.20% (141/190). The resistance rates of MRSA and MRCoNS to β-lactams drugs, such as penicillin, oxacillin, cefazolin, and cefuroxime were 100.00% in every year. No Staphylococcus strains resistant to vancomycin, teicoplanin, or linezolid were found. Three different PFGE patterns A, B, and C were identified among 40 MRSA strains, including 33 strains of type A (30 strains in sub-type A1 and 3 strains in sub-type A2), 6 strains of type B (respectively 3 strains in sub-types B1 and B2), and 1 strain of type C.</p><p><b>CONCLUSIONS</b>The isolation rates of MRSA and MRCoNS were high in our burn wards from January 2008 to December 2010. All of them showed strong drug resistance property, and they were multidrug resistant. The most prevalent strain was PFGE type A.</p>

Study of plasmid-mediated 16S rRNA methylase genes and drug-resistant transferability of Acinetobacter baumannii isolated from burn ward / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the drug-resistance of Acinetobacter baumannii (Ab) isolated from patients in burn ward, and study the incidence of 16S rRNA methylase genes mediated high-level aminoglycoside drug-resistance and its mechanism of transfer.</p><p><b>METHODS</b>A total of 40 Ab clinical isolates were collected from burn ward in Gansu Province People's Hospital from May 2006 to Dec. 2007. The sensitivity of Ab for 20 antibiotics were determinated by K-B agar diffusion. The minimal inhibitory concentrations (MIC) of amikacin, gentamicin, tobramycin, netilmicin, isepamicin and kanamycin against Ab strains were determinated by agar dilution. Five kinds of 16S rRNA methylase genes including armA, rmtA, rmtB, rmtC, rmtD were amplified by PCR, the positive PCR-products were purified and sequenced, and the plasmid were extracted by alkaline lysis. The transferability of drug-resistance were determinated by conjugation and plasmid transformation tests.</p><p><b>RESULTS</b>The drug-resistance rates of Ab against six aminoglycosides antibiotics was 72.5%, 72.5%, 70.0%, 67.5%, 70.0%, 70.0%, respectively. Twenty five strains were resistant to six aminoglycosides antibiotics (62.5%), among which 10 isolates were armA-positive (40.0%); rmtA, rmtB, rmtC and rmtD-positive isolates were not found. Ten transformants and 10 conjugates showed high-level resistance against aminoglycosides antibiotics, all of which the value of MIC > or = 256 microg/mL carried armA gene.</p><p><b>CONCLUSIONS</b>The drug-resistance of Ab clinical isolates have high drug-resistance. 16S rRNA methylases gene exists in Ab and locates in plasmid chromosome.</p>

Detection of integron, homology and genotype of carbapenemases in multi-drug resistant Acinetobacter Baumannii isolated from burn wound / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the relationship among antibiotic resistance, integron, homology of multi-drug resistant Acinetobacter Baumannii isolated from burn ward.</p><p><b>METHODS</b>Thirty-one strains of multi-drug resistant Acinetobacter baumannii were isolated from samples of burn wound exudate in hospitalized patients of Gansu Province People's Hospital. The minimum inhibitory concentrations (MIC) of these strains against 11 antibiotics was examined by agar dilution method. Homology of these strains was analyzed by pulse-field gel electrophoresis (PFGE). Class 1, 2 and 3 integrase, integron genes and genotype of carbapenemases were amplified by PCR and verified by DNA sequencing.</p><p><b>RESULTS</b>Acinetobacter baumannii were highly resistant to all antibiotics except imipenem, meropenem, cefoperazone-sulb-actam, piperacillin-tazobactam (antibiotic resistance rate was 45.2%, 48.4%, 48.4%, 41.0%, respectively). All strains were classified into 3 types of clones (A, B, C clone included 18, 7, 6 strains respectively) based on PFGE pattern. Integrons of 20 strains of Acinetobacter Baumannii harbored aadA1, aadA5, aacA4, aac3, catB8, aacC1, aac (6')-Ib, drfA17 and drf8 gene.</p><p><b>CONCLUSION</b>Multi-drug resistance Acinetobacter baumannii (major in clone A) spread widely in burn ward of Gansu Province People's Hospital. Integrons of Acinetobacter baumannii mediated drug resistance against aminoglycoside antibiotics, chloramp-phenicol. All carbapenem-resistant Acinetobacter Baumannii can produce OXA-23 carbapenemase.</p>

The protective effect of Rhadiola Astragalus Codonopsis compound on myocardium in early stage of severe burn at plateau in rats / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the severity of early myocardial injury in rats with 30% full thickness burn at plateau and the protective effects of Rhadiola Astragalus Codonopsis Compound (RACC) on the rat myocardial injury.</p><p><b>METHODS</b>One hundred and four Wistar rats with 30% full thickness burn were randomly divided into RACC application (R, n = 48) and scalding group 1 (S, n = 48), and another 8 healthy Wistar rats as control group 2 (C, n = 8). Four ml of RACC was garaged into the rat stomach in R and 4 ml isotonic saline in S groups respectively, but no treatment in C group. Blood samples from the aorta were harvested in 3, 6, 12, 24, 48 and 72 postburn hours (PBH) for blood gas analysis and for the determination of the changes in myocardial enzymes. Rat heart was harvested for pathomorphological examination.</p><p><b>RESULTS</b>The rat myocardial tissue injury in R and S groups was obvious at 3 PBH and ameliorated gradually thereafter, up to the degree in C group at 72 PBH. The serum levels of myocardial enzymes in R and S groups were significantly higher than those in C group (P < 0.01). Whereas the enzymes in R group were much lower than those in S group (P < 0.01). It was indicated by blood gas analysis that the pH in R and S groups was lower than that in C group (P < 0.05), while that in R group at 12 - 24 PBH was higher than that in S group (P < 0.05). In addition, the base excess in R and S groups was lower than that in C group (P < 0.01), while that in R group at 6 PBH was higher than that in S group (P < 0.05 approximately 0.01). The PaCO2 in R and S groups was evidently lower than that in C group (P < 0.05 approximately 0.01), while that in R group at 48 PBH was no different to that in C group (35.70 +/- 4.23 mmHg vs 37.50 +/- 6.53 mmHg, P > 0.05). The PaO2 in R and S groups at 3 approximately 24 PBH was higher than that in C group and decreased gradually (P > 0.05). There was no difference in SaO2 among 3 groups (P > 0.05).</p><p><b>CONCLUSION</b>RACC exhibited beneficial to the protection of rat heart from myocardial injury at plateau induced by severe burn.</p>