[Burow's solution treatment for external auditory canal and mastoid cavity cholesteatoma].

Burow's solution, 13% aluminum acetate dissolved in water developed as ear drops by German Dr. Karl August Burow in the mid-1800s, was confirmed by Mahoney (1980) and Thorp et al. (2000) to act on chronic suppurative otitis media without ototoxicity. We have found it satisfactory in treating otitis media and other intractable inflammation and fungal infection of the external auditory canal. We report its potent effect in 2 cases of external auditory canal cholesteatoma (EACC) and 1 of mastoid cavity cholesteatoma (MCC)-the first such report insofar as we knew. Case 1 of EACC involved an 8-year-old boy with cholesteatoma debris in a bony groove evidencing defective skin just posteroinferior to the left tympanic membrane. EACC was cured after a single Burow's solution instillation. Case 2 of EACC was a 31-year-old woman whose left ear canal was filled by a keratin mass with pus positive for methicillin-resistant staphylococcus aureus (MRSA) and granulation and experiencing otalgia and dysgeusia. Computed tomography (CT) showed that the bony anterior and posterosuperior wall of the external auditory canal had been destroyed. The EACC was removed and Burow's solution instilled once a week, effecting a cure about one month later, leaving the bony groove of the anterior and inferior wall intact and recovering gustatory sensation. Case 3 of MCC was a 47-year-old man undergoing right canal wall down tympanoplasty three times. One year after the last surgery, the mastoid cavity and posterior external canal wall was covered by a cholesteatoma matrix with granulation and pus. Instilling Burow's solution for 5 months resulted in a completely dry cholesteatoma-free cavity. All three subjects had intact tympanic membranes. Burow's solution alone proving effective against EACC and MCC suggests its great usefulness as first-choice conservative therapy. Although this usually cannot completely cure middle-ear and attic cholesteatoma, its effectiveness in cases of EACC and MCC should be recognized in infection and inflammation with cholesteatoma.

Establishment of a new embryonic stem cell line derived from C57BL/6 mouse expressing EGFP ubiquitously.

Transgenic mice ubiquitously expressing enhanced green fluorescent protein (EGFP) are useful as marker lines in chimera experiments. We established a new embryonic stem (ES) cell line (named B6G-2) from a C57BL/6 blastocyst showing ubiquitous EGFP expression. Undifferentiated B6G-2 cells showed strong green fluorescence and mRNAs of pluripotent marker genes. B6G-2 cells were transferred into a C57BL/6 blastocyst to generate a germline chimera, the progeny of which inherited ubiquitous EGFP expression. Mice derived completely from B6G-2 cells were also developed from the ES cells; these were tetraploid chimeras. The established B6G-2 cells were shown to be pluripotent and to be capable of differentiating into cells of all lineages. Thus, the new ES cell line expressing EGFP ubiquitously is useful for basic research in the field of regenerative medicine. The B6G-2 cell line is freely available from the BioResource Center, RIKEN Tsukuba Institute (http://www.brc.riken.jp/lab/cell/english/).