zahra eslaminejad

Espar is a dairy product of probiotic nature that contains useful bacteria and high calcium con-tent. The aim of this study was to analyze effects of daily consumption of Espar on the number of salivary mutans strepto-cocci and the level of calcium content in a population of 15 to 17 year-old female students. A double-blind randomized crossover study (n = 50) of healthy female adolescents was im-plemented in four stage intervals. The first and third stages were ‘run-in’ and ‘wash-out’ intervals. For the second and fourth stages, two weeks long in duration, the participants consumed 100 grams of Espar or 200 grams of plain yogurt. At the end of each stage, the number of salivary mutans streptococci and the level of calcium content were documented. There was a statistically significant decrease in the number of salivary mutans streptococci subsequent to Espar consumption when compared to ordinary yogurt (p < 0.01). Additionally, salivary calcium content increased significantly subsequent to the consumption of Espar and yogurt. However, Espar yielded a higher level of significant increase in sali-vary calcium when compared to plain yogurt (p < 0.01). This study found that daily consumption of Espar increased the salivary calcium level while decreasing mu-tans streptococci of the saliva.

The interest in using bacteria as anti- cancer therapeutic agents dates back to the end of the19th century. Some bacteria like Salmonella and Listeria replicate effectively inside malignant cell lines and suppress their growth. The bacterium Streptococcus pyogenes has become medically famous as a flesh-eating pathogen since mid-1980s. It is the causative agent of a life threatening clinical condition called necrotizing fasciitis. S. pyogenes usually produces a range of lytic enzymes that promote bacterial pathogenesis. With these characters, can S. be employed as a curing agent for certain cancers? The aim of this study was to determine the influence of S. pyogenes on malignant cellular death (apoptosis or necrosis)- in an ex-vivo "experimental- interventional" study.

The cytotoxicity of fifteen internalized streptococcal strains(including 12 clinical isolates, 2 known M types [M1, M3] and standard strain), on four types of malignant cell lines- A549, BT-20, PC-3, L-929- were tested by Trypan blue exclusion, DNAfragmentation and WST-1 methods. The streptococcal protease, lipase, DNase and serum opacity factor (SOF) were tested concurrently. The standard strain of Streptococcus (Enterococcus) faecalis was employed as negative control. The results were analyzed by statistical Minitab software.

The overall cytotoxicity rate of -internalized- S. pyogenes was 57% by trypan blue method and 50 % by DNA electrophoresis. False positive results occurred for the negative control in WST-1; therefore this test did not present reasonable results. The correlation between production of SOF, lipase, DNase and cytotoxicity of S. pyogenes was not significant (p > 0.05). However, 67% of the protease positive strains induced cellular death in at least one type of - malignant cell line (p<0.05).

Our findings indicated that, some non-invasive S. pyogenes that cause benign infection like pharyngitis can induce cell death in various cancerous cell lines. It seems that among bacterial products, the proteolytic enzymes-which are linked to the streptococcal pyrogenic exotoxin B (spe-B)- are more related to bacterial invasion.