Abstract: The cell observation using a conventional well plate takes much costs. Each well 3 being opened at a top plate 2a of the well plate 1 has a diameter reduced portion 32 which inner circumferential surface 32a is conically hollowed. At a lower portion of the diameter reduced portion 32 is formed an inserting hole 33. In a detecting portion 4, an outer circumferential surface of a round-bar reference electrode 41 is covered by an insulating portion 42. The detecting portion 4 has an upper end portion 4a and a lower end portion 4b which outer circumferential surface is exposed to an outside without being covered by an insulating portion 42. On an upper side above the lower end portion 4b is formed a diameter expanded portion 4c in which an outer circumferential surface of the insulating portion 42 is covered with a measuring electrode 43. The detecting portion 4 is fixed to a well 3 whose diameter expanded portion 4c is inserted into an inserting hole 33 and its upper end portion 4a is contained in the well 3.

Abstract: The cell observation using a conventional well plate takes much costs. Each well 3 being opened at a top plate 2a of the well plate 1 has a diameter reduced portion 32 which inner circumferential surface 32a is conically hollowed. At a lower portion of the diameter reduced portion 32 is formed an inserting hole 33. In a detecting portion 4, an outer circumferential surface of a round-bar reference electrode 41 is covered by an insulating portion 42. The detecting portion 4 has an upper end portion 4a and a lower end portion 4b which outer circumferential surface is exposed to an outside without being covered by an insulating portion 42. On an upper side above the lower end portion 4b is formed a diameter expanded portion 4c in which an outer circumferential surface of the insulating portion 42 is covered with a measuring electrode 43. The detecting portion 4 is fixed to a well 3 whose diameter expanded portion 4c is inserted into an inserting hole 33 and its upper end portion 4a is contained in the well 3.

Abstract: An object of the present invention is to efficiently establish cells, tissues, and organs capable of serving as donors for treating diseases, without eliciting immune rejection reactions, without starting with an egg cell. This object was achieved by providing a pluripotent stem cell having a desired genome. The cell was produced by treating with a reprogramming agent, producing a fusion cell of an MHC deficient stem cell with a somatic cell, or after producing a fusion cell of a stem cell with a somatic cell, removing a gene derived from the stem cell by performing genetic manipulation with a retrovirus.

Abstract: The present invention provides clonal pluripotent hepatic stem cells using flow cytometry and in vitro single-cell-based assays. These cells possess multilineage differentiation potential and self-renewing capability. These cells may be clonally propagated in culture, to continuously produce hepatocytes and cholangiocytes as descendants while maintaining primitive stem cells. When expanded cells are transplanted into recipient animals, they morphologically and functionally differentiated into hepatocytes and cholangiocytes, with reconstitution of hepatocyte and bile duct structures. Furthermore, these cells differentiated into pancreatic ductal and acinar cells or intestinal epithelial cells when transplanted into pancreas or duodenal wall. Thus, the self-renewing multipotent stem cells persist in the developing mouse liver and can be induced to become cells of other organs of endodermal origin under appropriate microenvironment, providing new insight into therapies for diseases of the digestive system.

Abstract: The sustaining stem cells for example, hematopoietic stem cells while holding in the undifferentiated state and maintaining pluripotency by providing a polypeptide having a WIF domain for example, WIF-1 to the stem cells has been successfully achieved. This polypeptide preferably also contains an EGF-like repeat. This result has been achieved by providing a polypeptide preferably having the WIF domain together with a stem cell survival factor such as SCF. Thus, it becomes possible to easily provide a large amount of stem cells for example, hematopoietic stem cells containing functional precursor cells. It has also become possible to more efficiently transfer a gene into the stem cells. Because it is homogeneous and almost free from impurities, the stem cell composition can remarkably relieve side effects for example, infection, which occur in conventional therapies using hematopoietic stem cells.

Abstract: A method and substance for regulating expansion of a stem cell, such as a hematopoietic stem cell, is provided. Therefore, a method is provided for regulating expansion of a stem cell, such as a hematopoietic stem cell, a germ line stem cell, or a neural stem cell, comprising the steps of (A) providing, to the stem cell, Bmi-1 or a variant or fragment thereof and/or a Bmi-1 regulating agent in an amount sufficient for regulation of the expansion of the stem cell and (B) culturing the stem cell for a time sufficient for the regulation of expansion.