DNA damaging effects of the dyes used in sentinel node biopsy: possible implications for clinical practice.

OBJECTIVE: This study investigates whether methylene blue (MB), patent blue V (PBV), and indigo carmine (IDC) commonly used in sentinel node biopsy cause DNA damage to breast epithelial cells in vitro. METHODS: MCF-7 and HB-2 cells were exposed for 5 minutes to the above dyes at the same concentrations used in clinical practice. Following exposure, the comet assay was performed to detect DNA damage. The enzyme, Fapy-DNA glycosylase (FpG) was incorporated to enable the detection of additional oxidative damage. RESULTS: Both PBV and MB stimulated DNA strand breaks in both MCF-7 and HB2 cell lines (P < 0.05). Levels were elevated over 3-fold (P < 0.05) in MCF-7 and HB2 cells treated with 2.5% PBV and 1% MB, compared with untreated control cells. In contrast, IDC did not stimulate DNA strand break damage at clinically relevant concentrations in either cell line. Addition of Fapy-DNA glycosylase enzyme also revealed significantly (P < 0.05) increased levels of oxidative DNA lesions (ODL) in MCF-7 cells treated with PBV (17.6% ODL) compared with control cells (5.9% ODL). CONCLUSIONS: This study shows, for the first time, that certain dyes (MB and PBV) commonly used in SLNB have genotoxic effects on breast cells at clinically relevant concentrations in vitro. In vivo studies are now warranted to assess and minimize DNA damage caused by these dyes during SLNB.

A rare complication of a common disease: Bouveret syndrome, a case report.

This is a case report of an 85-year old patient who presented with abdominal pain, nausea and vomiting associated with altered liver function test. The plain X-rays and CT scan showed pneumobilia with an ectopic gallstone. The patient was diagnosed with Bouveret syndrome and managed surgically. The report is followed by a discussion about Bouveret syndrome.