Merkel cell carcinoma is a rare malignancy that sometimes occurs in the skin of elderly people. Recently, a new human polyomavirus, Merkel cell polyomavirus (MCPyV) was identified in Merkel cell carcinoma. In the present study, MCPyV-DNA was detected in 6 of 11 (55%) cases of Merkel cell carcinoma by nested PCR and real-time PCR. Histologically, MCPyV-positive cases showed round and vesicular nuclei with a fine granular chromatin and small nucleoli, whereas MCPyV-negative cases showed polygonal nuclei with diffusely distributed chromatin. Real-time PCR analysis to detect the MCPyV gene revealed that viral copy numbers ranged 0.04-0.43 per cell in cases of Merkel cell carcinoma. MCPyV was also detected in 3 of 49 (6.1%) cases of Kaposi's sarcoma (KS), but not in 192 DNA samples of other diseases including 142 autopsy samples from 20 immunodeficient patients. The MCPyV copy number in KS was lower than that in Merkel cell carcinoma. PCR successfully amplified a full-length MCPyV genome from a case of KS. Sequence analysis revealed that the MCPyV isolated from KS had 98% homology to the previously reported MCPyV genomes. These data suggest that the prevalence of MCPyV is low in Japan, and is at least partly associated with the pathogenesis of Merkel cell carcinoma.

To clarify whether mutations in the large T gene encoded by Merkel cell polyomavirus affect the expression and function of large T antigen in Merkel cell carcinoma cases, we investigated the expression of large T antigen in vitro and in vivo. Immunohistochemistry using a rabbit polyclonal antibody revealed that large T antigen was expressed in the nuclei of Merkel cell carcinoma cells with Merkel cell polyomavirus infection. Deletion mutant analyses identified an Arg-Lys-Arg-Lys sequence (amino acids 277-280) as a nuclear localization signal in large T antigen. Sequence analyses revealed that there were no mutations in the nuclear localization signal in any of the eleven Merkel cell polyomavirus strains examined. Furthermore, stop codons were not observed in the upstream of the nuclear localization signal in any of the Merkel cell carcinoma cases examined. These data suggest that the nuclear localization signal is highly conserved and functional in Merkel cell carcinoma cases.

Burns are a common type of skin injury encountered at all levels of medical facilities from private clinics to core hospitals. Minor burns heal by topical treatment alone, but moderate to severe burns require systemic management, and skin grafting is often necessary also for topical treatment. Inappropriate initial treatment or delay of initial treatment may exert adverse effects on the subsequent treatment and course. Therefore, accurate evaluation of the severity and initiation of appropriate treatment are necessary. The Guidelines for the Management of Burn Injuries were issued in March 2009 from the Japanese Society for Burn Injuries as guidelines concerning burns, but they were focused on the treatment for extensive and severe burns in the acute period. Therefore, we prepared guidelines intended to support the appropriate diagnosis and initial treatment for patients with burns that are commonly encountered including minor as well as moderate and severe cases. Because of this intention of the present guidelines, there is no recommendation of individual surgical procedures.

A new method was developed for detection of human papillomavirus (HPV) by loop-mediated isothermal amplification (LAMP), which was compared with the polymerase chain reaction (PCR), and real-time PCR for specificity and sensitivity. All initial validation studies with the control DNA proved to be type-specific. In order to evaluate the reliability of HPV type-specific LAMP detecting HPV DNA from clinical samples, tissue specimens were obtained from 27 patients with external genital polypoid lesions. The histologic diagnoses included condyloma acuminatum (n = 21), bowenoid papulosis (n = 2), seborrheic keratosis (n = 2), epidermolytic acanthoma (n = 1), and hairy nymphae (n = 1). HPV-6 DNA and HPV-11 DNA were detected in 18 and 3 of 21 condylomata acuminata, respectively, and there was no simultaneous infection. HPV-16 DNA was detected in one of two bowenoid papuloses. HPV DNA was not detected in the seborrheic keratoses, epidermolytic acanthoma, and hairy nymphae. These results correlated perfectly with those from real-time PCR analysis. Most positive samples contained high copy numbers of HPV DNA. HPV-11 DNA was detected in one case that could not be detected by PCR. The average reaction time was about 59 min. There was a linear correlation between the genome quantity and reaction time to reach the threshold. The LAMP method has an additional advantage as a quantitative method, and is superior in terms of sensitivity, specificity, rapidity, and simplicity, and can potentially be a valuable tool for the detection of HPV DNA.