Yasuhiro Kawachi

Cutaneous infection due to Mycobacterium szulgai in a patient with myelodysplastic syndrome

was done and numerous whitish colonies were observed after 1 week (Fig. 1f). For identification of the mycobacterial species, we performed polymerase chain reaction hybridization and erythromycin ribosome methyltransferase gene polymerase chain reaction (PCR). As a result, it was identified as M. massiliense. In addition, we took an ultrasound-guided lymph node needle biopsy in the left inguinal area. Histopathological findings showed reactive hyperplasia with granulomatous histiocytic infiltration but negative results in Gram, PAS, AFB staining and culture(Fig. 1e). As drug sensitivity tests revealed sensitivity to clarithromycin, oral clarithromycin 500 mg/day was administrated for 5 months and incision and drainage was performed intermittently. The lesions had decreased in size and recurrence was not observed after discontinuation of medication (Fig. 1c). Mycobacterium massiliense was first described as a new species from the M. abscessus and M. chelonae group by Adekambi et al. Clinically, cutaneous M. massiliense infections manifest as disseminated subcutaneous nodules in immunocompromised patient and skin nodules, ulcer and abscess at traumatic sites in immunocompetent individuals. There are less than 10 reported cases of cutaneous M. massiliense worldwide. Among these, just three cases were not preceded by a previous event. This infection is usually assumed to have originated from an environmental source but it may occur in immunocompetent patients without antecedent event. It is usually difficult to diagnose non-tuberculous mycobacterium (NTM) because of its various clinical manifestations and lower sensitivity of culture results. However, it is important to find out the causative microorganism at the species level to manage infection. To diagnose NTM infection, real-time PCR assay is a very useful tool because of its accuracy and rapidness. Previously, combination therapy including clarithromycin with other antibiotics has been used empirically for the treatment against M. massiliense. At present, we treat our patient with clarithromycin alone and with good improvement. Long-term medication is recommended to prevent recurrence.

p62 modulates the intrinsic signaling of UVB-induced apoptosis

BACKGROUNDnUVB radiation is the main source of sunburn and skin cancers. Apoptosis eliminates photodamaged cells, and is thus important for preventing epidermal carcinogenesis. The cytoplasmic regulatory protein p62/A170/sequestosome 1 (p62) molecule is involved in a variety of cellular and signaling pathways. p62 is known to be and important in autophagy, but its role in UVB-induced apoptosis remains to be clarified.nnnOBJECTIVEnTo investigate the role of p62 against UVB-induced apoptotic changes, using mouse embryonic fibroblasts (MEFs) derived from p62 homozygous knockout (p62(-/-)) mice.nnnMETHODSnp62(-/-) and wild-type (p62(+/+)) mice and MEFs were subjected to UVB irradiation, and the resultant apoptosis was analyzed using flow cytometry, quantitative real-time PCR, and western blots.nnnRESULTSnApoptosis was decreased in the p62(-/-) MEFs compared to p62(+/+) MEFs in response to UVB treatment. Compared with p62(+/+) MEFs, p62(-/-) MEFs expressed significantly more Bcl-2 and less Bax, and showed increased Src and Stat3 phosphorylation. Our results show that p62 regulates apoptotic pathways by modifying critical signaling intermediates such as Src and Stat3.nnnCONCLUSIONnp62 deficiency [corrected] reduces UVB-induced apoptosis by modulating intrinsic apoptotic signaling through Src phosphorylation.