Clostridia in cancer therapy

During the past decade, the search for an effective system for the selective delivery of high therapeutic doses of anti-cancer agents to tumours has explored a variety of ingenious and increasingly complex biological systems. These systems are most often based on gene therapy and use viral vectors as the delivery vehicle. Invariably, such systems have been found wanting with respect to a lack of tumour specificity, poor levels of transgene expression and inefficient distribution of the vector throughout the tumour mass. By contrast, the ability of intravenously injected clostridial spores to infiltrate, then selectively germinate in, the hypoxic regions of solid tumours seems to be a totally natural phenomenon, which requires no fundamental alterations and is exquisitely specific.     

Relationship between dental morphology, sex, body length and age in Pontoporia blainvillei and Sotalia fluviatilis (Cetacea) in Northern Rio de Janeiro, Brazil

The relationship between dental morphology, sex, body length and age of small cetaceans can be used to determine ontogeny, sexual dimorphism and geographical variation. The objective of this study was to determine the relationship between dental morphology, sex, body size and age. A total of 91 specimens of P. blainvillei and 80 specimens of S. fluviatilis accidentally captured in fisheries or stranded in northern Rio de Janeiro (21 masculine37'-22 masculine25'S), from September 1988 to November 1996 were analysed. The teeth root diameter in P. blainvillei was significantly different between the sex; the values for females were larger than males. In neither species aid we observed significant in variations dimension and number of teeth, thickness of dentine and cemental layers and in the maximum width of cement as a function of body size. Age was related to increases in tooth length, root and cingulum diameters, and maximum width of cement in individuals of P. blainvillei, and tooth and crown lengths and maximum width of cement in individuals of S. fluviatilis. The observation of a linear growth between maximum width of cement and age in both species indicates that the equations obtained can be used to estimate relative age in P. blainvillei and S. fluviatilis in northern of Rio de Janeiro.     

Survival Rate and Enzyme Activities ofLactobacillus acidophilusFollowing Frozen Storage

The ability of two strains of Lactobacillus acidophilus, CRL 640 and CRL 800, to survive and retain their biological activities under frozen storage was determined. Freezing and thawing, as well as frozen storage, damaged the cell membrane, rendering the microorganisms sensitive to sodium chloride and bile salts. Both lactic acid production and proteolytic activity were depressed after 21 days at -20 degreesC, whereas beta-galactosidase activity per cell unit was increased. Cell injury was partially overcome after repair in a salt-rich medium. Copyright 1998 Academic Press.     

The SOS Response Master Regulator LexA Is Associated with Sporulation,Motility and Biofilm Formation in Clostridium difficile

The LexA regulated SOS network is a bacterial response to DNA damage of metabolic or environmental origin. In Clostridium difficile, a nosocomial pathogen causing a range of intestinal diseases, the in-silico deduced LexA network included the core SOS genes involved in the DNA repair and genes involved in various other biological functions that vary among different ribotypes. Here we describe the construction and characterization of a lexA ClosTron mutant in C. difficile {"type":"entrez-nucleotide","attrs":{"text":"R20291","term_id":"774925"}}R20291 strain. The mutation of lexA caused inhibition of cell division resulting in a filamentous phenotype. The lexA mutant also showed decreased sporulation, a reduction in swimming motility, greater sensitivity to metronidazole, and increased biofilm formation. Changes in the regulation of toxin A, but not toxin B, were observed in the lexA mutant in the presence of sub-inhibitory concentrations of levofloxacin. C. difficile LexA is, therefore, not only a regulator of DNA damage but also controls many biological functions associated with virulence.     

Changes in urinary dinor dihydro F(2)-isoprostane metabolite concentrations, a marker of oxidative stress, during and following asthma exacerbations

To investigate changes in oxidant stress during and following acute asthma exacerbations, this study measured 2,3-dinor-5,6-dihydro-15-F(2t)-IsoP (F(2)-IsoP-M), the major urinary metabolite of 15-F(2t)-IsoP, in eight asthmatic adults, during and following an asthma hospitalization. F(2)-IsoP-M concentrations at admission and follow-up were significantly higher than discharge (admission median: 4.12 ng/Cr mg, range 1.89-7.8; follow-up: 2.47 ng/Cr mg (1.56-6.86); discharge: 1.42 ng/Cr mg (0.7-4.44); both p<0.01), but not significantly different between admission and follow-up. F(2)-IsoP-M concentrations at follow-up were higher than a control group with stable asthma (0.68 ng/Cr mg (0.31-1.5), p=0.0008). In conclusion, asthma exacerbations requiring hospitalization are associated with 6-fold higher urinary F(2)-IsoP-M concentrations compared to stable asthmatics. F(2)-IsoP-M concentrations decreased significantly during hospitalization, but significant elevations 3 months following hospitalization suggest ongoing oxidative stress despite clinical improvement. Urinary F(2)-IsoP-M may be a clinically useful, simple non-invasive systemic measure of oxidative stress in asthmatics, providing information not captured by spirometry or symptoms.