Akiyuki Murano

Acidic conditions enhance bactericidal effects of sodium bisulfite on Helicobacter pylori

Background.  The Brucella broth medium, which is often used for the cultivation of microaerobic bacteria including Helicobacter pylori. It contains sodium bisulfite to decrease oxygen content in the medium. The growth of H. pylori, however, is inhibited by sodium bisulfite. In this study, the effect of sodium bisulfite was compared with several antioxidants and quantified under acidic conditions, mimicking the gastric environment.

Enhancement of the Growth of Helicobacter pylori in Brucella Broth by Hydrogen Peroxide

We found that a sub‐lethal concentration of hydrogen peroxide (HPOx) enhanced the growth of Helicobacter pylori in Brucella broth supplemented with 10% fetal bovine serum (BB/FBS). The enhancement was evident at 0.1 mM HPOx and reached a maximun at 3.5 mM. The growth stimulation was dependent on the basal media used; when brain heart infusion broth (BHIB) was used instead of BB, the growth was not altered regardless of the presence or absence of HPOx. Furthermore, the growth in BHIB/FBS was comparable to that in BB/FBS plus 3.5 mM HPOx. This suggested that the enhancement of growth by HPOx resulted from the derepression of the inhibitory factor existing in BB by HPOx. The inhibitory substance seemed to be bisulfite salt since the bacteria grew to a similar extent in bisulfite‐less Brucella broth (BLBB)/FBS compared to the bacterial growth in BHIB/FBS and BB/FBS plus HPOx. These results indicate that the detoxification of bisulfite in BB can be easily achieved by simply adding HPOx to the medium, which causes the oxidation of bisulfite to bisulfate, a less‐toxic compound to the bacterial growth. Since we also found that the morphology and cellular protein profile of BB/FBS‐cultured bacteria were apparently different from those cultured in BLBB/FBS, we propose that the use of BB for primary isolation and cultivation of H. pylori should be limited on certain occasions, or if necessary, BB can be used after detoxification of the bisulfite by the addition of a low concentration of HPOx.

Downregulation of Tumour Suppressor Gene TSLC1 mRNA in Human Oral Squamous Cell Carcinoma

Abstract Objectives: To identify changes in the expression patterns of the TSLC1 (tumour suppressor in lung cancer 1) gene family in oral squamous cell carcinoma. Materials and Methods: DNA microarray was performed to analyse gene expression of the TSLC1 gene family in oral squamous cell carcinoma—derived cell lines (HSC2, HSC3, Ca9-22, and Sa3) when compared with normal oral keratinocytes using high-density Affymetrix U133 plus 2.0 GeneChip arrays containing 54,675 probe sets. Comparison of TSLC1 mRNA expression levels between 30 primary oral squamous cell carcinomas and normal tissues was performed by real-time quantitative reverse transcriptase polymerase chain reaction, which was used to confirm the microarray results. Results: Microarray analysis demonstrated TSLC1 expression levels that were downregulated at least 2-fold or more in 3 of 4 oral squamous cell carcinoma-derived cell lines (75%) compared with normal oral keratinocytes. Significant downregulation of TSLC1 expression levels was shown by real-time quantitative reverse transcriptasepolymerase chain reaction analysis in all oral squamous cell carcinoma—derived cell lines and 23 (77%) of 30 primary oral squamous cell carcinomas (p Conclusions: These results suggest that the TSLC1 gene is frequently altered in oral squamous cell carcinoma. This alteration may contribute to carcinogenesis in oral cancer.