1. Department of Nursing, Faculty of Health and Welfare Science; Okayama Prefectural University; Sohja Okayama 719-1197 Japan
2. Department of Nutrition, Faculty of Health and Welfare Science; Okayama Prefectural University; Sohja Okayama 719-1197 Japan
3. First Department of Surgery; Okayama University Medical School; Okayama Okayama 700-8558 Japan
4. Department of Microbiology; Jichi Medical School; Tochigi 329-0431 Japan