Preventive effect of gelatinizedly-modified chitosan film on peritoneal adhesion of different types

AIM： To comparatively study the preventive effect of gelatinizedly-modified chitosan film on peritoneal adhesions induced by four different factors in rats. METHODS： Chitosan was chemically modified by gelatinization, and made into films of 60 μm in thickness, and sterilized. Two hundred Sprague-Dawley rats were randomly divided into five groups, Sham-operation group （group A）, wound-induced adhesion group （group B）, purified talc-induced adhesion group （group C）, vascular ligation-induced adhesion group （group D）, and infection-induced adhesion group （group E）, respectively. In each group, the rats were treated with different adhesion-inducing methods at the cecum of vermiform processes and then were divided into control and experimental subgroups. Serous membrane surface of vermiform processes were covered with the films in the experimental subgroups, and no films were used in the control subgroups. After 2 and 4 wk of treatments, the abdominal cavities were reopened and the adhesive severity was graded blindly according to Bhatia＇s method. The cecum of vermiform processes were resected for hydroxyproline （OHP） measurement and pathological examination. RESULTS： Adhesion severity and OHP level： After 2 and 4 wk of the treatments, in the experimental subgroups, the adhesions were significantly lighter and the OHP levels were significantly lower than those of the control subgroups in group B （2 wk： 0.199 ± 0.026 vs 0.285 ± 0.041 μg/mg pr, P 〈 0.001; 4 wk： 0.183 ± 0.034 vs 0.276 ± 0.03 μg/mg pr, P 〈 0.001）, D （2 wk： 0.216 ± 0.036 vs 0.274 ± 0.040 μg/mg pr, P = 0.004; 4 wk： 0.211 ± 0.044 vs 0.281 ± 0.047 μg/mg pr, P = 0.003） and E （2 wk： 0.259 ± 0.039 vs 0.371 ± 0.040 μg/mg pr, P 〈 0.001; 4 wk： 0.242 ± 0.045 vs 0.355 ± 0.029 μg/mg pr, P 〈 0.001）, but there were no significant differences in groups A （2wk： 0.141 ± 0.028 vs 0.137 =k 0.026 μg/mg pr, P = 0.737; 4 wk： 0.132 ± 0.031 vs 0.150 ± 0.035 μg/mg pr, P = 0.225） and C （2 wk： 0.395 ± 0.044 vs 0.378 ± 0.043 μg/mg pr, P = 0.387; 4 wk： 0.370 ± 0.032 vs 0.367 ± 0.041 μg/mg pr, P = 0.853）; Pathological changes： In group B, the main pathological changes were fibroplasias in the treated serous membrane surface and in group D, the fibroplasia was shown in the whole layer of the vermiform processes. In group E, the main pathological changes were acute and chronic suppurative inflammatory reactions. These changes were lighter in the experimental subgroups than those in the control subgroups in the three groups. In group C, the main changes were foreign body giant cell and granuloma reactions and fibroplasias in different degrees, with no apparent differences between the experimental and control subgroups. CONCLUSION： The gelatinizedly-modified chitosan film is effective on preventing peritoneal adhesions induced by wound, ischemia and infection, but the effect is not apparent in foreign body-induced adhesion.

Life-threatening meningitis resulting from transrectal prostate biopsy

After antibiotic prophylaxis with metronidazole and levofloxacin, a transrectal sextant biopsy was performed under the guide of transrectal ultrasonography （TRUS） for a 75-year-old suspicious patient with prostate adenocarcinoma. Although antibiotics were also given after this procedure, the patient still developed fever, anxious, agrypnia and headache. Blood cultures remained negative. Lumbar puncture was performed and was consistent with Escherichia coli bacterial meningitis.

Antitumor effects of human interferon-alpha 2b secreted by recombinant bacillus Calmette-Guérin vaccine on bladder cancer cells

Objective:Our objective was to construct a recombinant bacillus Calmette-Guérin vaccine(rBCG) that secretes human interferon-alpha 2b(IFNα-2b) and to study its immunogenicity and in vitro antitumor activity against human bladder cancer cell lines T24 and T5637.Methods:The signal sequence BCG Ag85B and the gene IFNα-2b were amplified from the genome of BCG and human peripheral blood,respectively,by polymerase chain reaction(PCR).The two genes were cloned in Escherichia coli-BCG shuttle-vector pMV261 to obtain a new recombinant plasmid pMV261-Ag85B-IFNα-2b.BCG was transformed with the recombinant plasmid by electroporation and designated rBCG-IFNα-2b.Mononuclear cells were isolated from human peripheral blood(PBMCs) and stimulated with rBCG-IFNα-2b or wild type BCG for 3 d,and then cultured with human bladder cancer cell lines T24 and T5637.Their cytotoxicities were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay.Results:BCG was successfully transformed with the recombinant plasmid pMV261-Ag85B-IFNα-2b by electroporation and the recombinant BCG(rBCG-IFNα-2b) was capable of synthesizing and secreting cytokine IFNα-2b.PBMC proliferation was enhanced significantly by rBCG-IFNα-2b,and the cytotoxicity of PBMCs stimulated by rBCG-IFNα-2b to T24 and T5627 was significantly stronger in comparison to wild type BCG.Conclusions:A recombinant BCG,secreting human IFNα-2b(rBCG-IFNα-2b),was constructed successfully and was superior to control wild type BCG in inducing immune responses and enhancing cytotoxicity to human bladder cancer cell lines T24 and T5637.This suggests that rBCG-IFNα-2b could be a promising agent for bladder cancer patients in terms of possible reductions in both clinical dosage and side effects of BCG immunotherapy.