The reproductive life-history of molluscs can be divided into gonochorism and hermaphroditism, while hermaphroditism is further classified into simultaneous (synchronous or functional) and sequential (asynchronous) (Heller 1993 Gosling 2004). Approximately 40% of the 5600 mollusc genera are either simultaneous or sequential hermaphrodites. Hermaphroditism occurs in 100% of the Solenogastres, 99% of the Opisthobranchia, 100% of the Pulmonata, 3% of the Prosobranchia and 9% of the Bivalvia. Simultaneous hermaphroditism is the simultaneous release of eggs and sperm by one organism during the same season. Sequential hermaphroditism is the function of an organism first as one sex, then as another (Heller 1993). This study investigated the sex of Manila clam, Ruditapes philippinarum by verifying changes in sex ratio (F:M) with size and sex reversal stages. Adult one-year-old (11 months; SL 36.75±3.0 mm) R. philippinarum were used for sex reversal identification. Each individual was tagged on its shell prior to being reared in the wild for reproductive analysis, and sex was confirmed using the germ cell aspiration (GCA) method. Sex ratio (F:M) at the commencement of the study (June 2009) was 1:1.23, but changed to 1:0.87 by the end (July 2010). Overall sex reversal rate was 19.0%. Specifically, male to female sex reversal ratio was 21.05%, which was higher than the female to male sex reversal ratio of 12.9%. Based on our results, R. philippinarum has been confirmed to possess a sequentially hermaphroditic life-history.

Adult stem cells can make identical copies of themselves for long periods of time. They also give rise to many differentiated mature cell types that have characteristic morphology and specialized function. Human adult stem cells are the attractive raw materials for the cell/tissue therapy, however, it is not easy to get from the adult tissues. In the present study, we tried to isolate a cell population derived from human umbilical cord vein which has been discarded after birth. The cells were isolated after treatment of the umbilical vein with collagenase or trypsin. After 3 days of culture, two kinds of cell populations were found consisting of adherent cells with endothelial cell-like and fibroblast-like morphology, respectively. When these cells were subcultured 12 times over a period of 3 months, almost cells appeared uniformly to exhibit fibroblastoid morphology which was different from that of mesenchymal stem cells obtained from human bone marrow The results of RT-PCR analyses showed distinct expression of BMP-4, oct-4, and SCF genes but not of GATA, PAX-6 and Brachyury genes. On immunohistochemical staining, the cells were negative for the von Willebrand factor(vWF), alpha-smooth muscle actin and placental alkaline phosphatase. From these observations, it is suggested that stem-like cells might be present in human umbilical cord vein.

심신수련의 일종인 기수련이 뇌호르몬계와 면역계에 미치는 영향을 살펴보기 위하여 9명의 건강한 노인을 대상으로 혈중내 코티졸, 성장호르몬과 멜라토닌의 변화와 호중구의 초과산화 이온 분비량을 조사하였다. 한시간의 기수련은 코티졸을 유의하게 감소시켰으며, 성장호르몬과 멜라토닌의 분비를 증가 시켰다. 또한 초과산화이온이 기수련에 의해 유의하게 변화하였으며 수련직후네 수련전에 비하여 유의한 차이가 있었다. 이러한 결과는 기수련이 코티졸, 성장호르몬, 멜라토닌등을 변화시켜 호중구의 기능을 증가시킨것이라 볼 수 있다. 호중구의 기능의 증가는 기수련을 통하여 일반적 감염과 염증반응에 저항력을 높여주는 것으로 생각된다.