Bacteriolytic therapy of experimental pancreatic carcinoma

AIM:To investigate the effectiveness of Clostridium novyi(C.novyi)-NT spores for the treatment of established subcutaneous pancreatic tumor in the syngeneic,immunocompetent Panc02/C57Bl/6 model. METHODS:C.novyi-NT spores were applied intravenously to animals carrying established pancreatic tumors of three different sizes.Systemic immune responses in peripheral blood and spleen were examined by flow cytometry.Supplementary,cytotoxic activity of lymphocytes against syngeneic tumor targets was analyzed. RESULTS:Application of spores identified,that(1) small tumors(<150 mm 3 )were completely unaffected (n=10);(2)very large tumors(>450 mm3)responded with substantial necrosis followed by shrinkage and significant lethality most likely due to tumor lysis syndrome (n=6);and(3)an optimal treatment window exists for tumors of approximately 250 mm 3 (n=21).In this latter group,all tumor-bearing animals had complete tu-mor regression and remained free of tumor recurrence. In subsequent tumor rechallenge experiments a significant delay in tumor growth compared to the initial tumor cell inoculation was observed(tumor volume at day 28:197.8±87.3 mm 3 vs 500.1±50.9 mm3,P<0.05). These effects were accompanied by systemic activation of immune response mechanisms predominantly mediated by the innate arm of the immune system. CONCLUSION:The observed complete tumor regression is encouraging and shows that immunotherapy with C.novyi-NT is an interesting strategy for the treatment of pancreatic carcinomas of defined sizes.

Bacteriophage therapy against Enterobacteriaceae

The Enterobacteriaceae are a class of gram-negative facultative anaerobic rods, which can cause a variety of diseases, such as bacteremia, septic arthritis, endocarditis, osteomyelitis, lower respiratory tract infections, skin and soft-tissue infections, urinary tract infections, intra-abdominal infections and ophthalmic infections, in humans, poultry, animals and fish. Disease caused by Enterobacteriaceae cause the deaths of millions of people every year, resulting in enormous economic loss. Drug treatment is a useful and efficient way to control Enterobacteriaceae infections. However, with the abuse of antibiotics, drug resistance has been found in growing number of Enterobacteriaceae infections and, as such, there is an urgent need to find new methods of control. Bacteriophage therapy is an efficient alternative to antibiotics as it employs a different antibacterial mechanism. This paper summarizes the history of bacteriophage therapy, its bacteriallytic mechanisms, and the studies that have focused on Enterobacteriaceae and bacteriophage therapy.

Immunotoxicity Effect of Benzo[α]Pyrene on Scallop Chlamys farreri

The toxic effects of benzo[α]pyrene （B[α]P） at different concentrations （0.1, 0.5, 1, 2.5 and 7.5 μgL^-1） on scallop （Chlamys farreri） immune system were studied. The results showed that B[α]P had significant toxic effects on the haemocyte counts, neutral red uptake, phagocytosis, bacteriolytic and antibacterial activity （P〈0.05）, while the seawater control and acetone control had no significant differences. The haemocyte counts, neutral red uptake, phagocytosis and bacteriolytic activity in all B[α]P treatment groups as well as antibacterial activity in groups of 0.5, 1, 2.5 and 7.5 μgL^-1·B[α]P decreased significantly （P〈0.05）. Some of these indices tended to be stable on the sixth day and others on the ninth day, and the indices showed clear time- and concentration-response to B[α]E Bactenolytic activity in 0.1 μgL^-1 B[α]P treatment group and antibacterial activity in 0.1 ggLl and 0.5 μgL^-1 B[α]P treatment groups increased at the beginning of exposure and reached their peaks on day 1 and day 6, respectively. Following that, both activities decreased gradually and became stable after day 9. When all the indices reached stability, they were significantly lower than those in control group （P〈0.05）, except for antibacterial activity in 0.1 μgLl B[α]P treatment group （P〉0.05）. Thus, B[α]P has evident toxic effects on scallop immune system, which supports the view that a relationship exists between pollution and lmmunomodulation in aquatic organisms.