Biomedical subjects

Yi-Lan Wang

Publications and source records attributed to Yi-Lan Wang.

4 recordsLinked to original sources

PubMed2005

Histone acetylation affects expression of cellular patterning genes in the Arabidopsis root epidermis.

The Arabidopsis root has a unique cellular pattern in its single-layered epidermis. Cells residing over the intercellular spaces between underlying cortical cells (H position) differentiate into hair cells, whereas those directly over cortical cells (N position) differentiate into non-hair cells. Recent studies have revealed that this cellular pattern is determined by interactions of six patterning genes CPC, ETC, GL2, GL3/EGL3, TTG, and WER, and that the position-dependent expression of the CPC, GL2, and WER genes is essential for their appropriate interactions. However, little is known about how the expressions of the pattern genes are determined. Here we show that trichostatin A (TSA) treatment of germinating Arabidopsis seedlings alters the cellular pattern of the root epidermis to induce hair cell development at nonhair positions. The effects of TSA treatment are rapid, reversible, concentration-dependent, and position-independent. TSA inhibition of histone deacetylase activity results in hyperacetylation of the core histones H3 and H4, and alters the expression levels and cell specific expression of the patterning genes CPC, GL2 and WER. Analysis of histone deacetylase mutant cellular patterning further verified the participation of histone acetylation in cellular patterning, and revealed that HDA18 is a key component in the regulatory machinery of the Arabidopsis root epidermis. We propose a working model to suggest that histone acetylation may function in mediating a positional cue to direct expression of the patterning genes in the root epidermal cells.

Arabidopsis↗

PubMed2004

[Study on non-programmed process using dimethyl sulfoxide and hydroxyethyl starch as cryoprotectants in cryopreservation of cord blood hematopoietic cells].

This study was aimed to search for effective cryoprotectants and freezing methods used in cord blood bank (CBB) for cryopreservation of cord blood hematopoietic stem cells. The non-programmed group using 8% final concentration of dimethyl sulfoxide (DMSO) and 5% final concentration hydroxyethyl starch (HES) (molecular weight 120,000) as protectants and group of conventional of programmed controller method using 10% DMSO only as cryoprotectant in cryopreservation of cord blood hematopoietic stem cells were compared. In each of the two groups, 15 cord blood units were used. In non-programmed group, cord blood units put in -80 degrees C refrigerator for 24 hours as a transitional step before deep-freezing in liquid nitrogen, when both of DMSO and HES had been added. The recoveries of the nuclear cells number, the yield of granulocyto-macrophage colony forming units (CFU-GM) and the cells viability in cord blood units before preservation and after thawing were tested for both methods. The results showed that no significant difference was found in above assays between two groups. The clinical application results also showed that hematopoietic engraftment rates after infusion were similar in both groups. It is concluded that the non-programmed method by -80 degrees C refrigerator as a transitional step and using the combined two protectants seems simple in operation and effective in clinical transplantation as well as the conventional programmed method.

Cryopreservation↗

PubMed2001

[A Experimental Study on Improvement of the Seeding Efficiencies of Infused Donor Hematopoietic Cells in Syngeniec Bone Marrow Transplantation by Aortic Infusion]

In order to explore the improvement of seeding efficiencies of infused donor hematopoietic cells to bone marrow in bone marrow transplantation, two recipient groups of syngeneic rat model which received transplanted cells labeled with PKH-26, a red fluorescent membrane dye, by aortic or intravenous administration (2 x 10(7) nucleate cells per recipient rat) respectively, were assayed; at selected times following BMT, partial recipient rat were euthanized and then measured the numbers of PKH-26 labeled cells in recipient rat marrow samples by means of flow cytometry. The results showed that the homing indices of donor hematopoietic cells in aortic group and intravenous group were (14.52 +/- 1.07)% and (10.49 +/- 0.72)% at 30 hours after BMT, respectively (P < 0.05). The results indicated that the number of donor hematopoietic cells localized to recipient bone marrow infused by aortic route is more than that infused by intravenous route.

Journal Article↗

PubMed2001

[Donor Hematopoietic Cell Tracking In Vivo at the Homing Phase of Allo-Bone Marrow Transplantation in Mice]

It has been well-known that intravenously infused hematopoietic stem and progenitor cells can home to the bone marrow and reconstitute hematopoiesis. However, little is understood about the homing efficiency or percentage of infused stem and progenitor cells. In order to examine distribution pattern of infused hematopoietic cells in the organs and tissues, a direct assay system to trace transplanted cells in vivo by employing PKH-26, a red fluorescent membrane dye, to label hematopoietic cells in inbred strain of mice transplanted cells (stem cell antigen-1 positive subpopulation cell, Sca-1(+) cells) was introduced. The numbers of labeled cells was measured by means of flow cytometry and fluorescence microscopy. The early fate of infused Sca-1(+) donor bone marrow cells after intravenous administration in a allogeneic mouse model was examined. The presence of infused donor cells with the fluorescent dye PKH-26 was evaluated within 60 hours in hematopoietic organ (bone marrow and spleen) and non-hematopoietic organ (lungs and liver) of recipients. The data showed that (1) Following intravenous infusion, Sca-1(+) donor bone marrow cells were detained in lungs shortly. (2) Sca-1(+) donor bone marrow cells localized to both hematopoietic organ (bone marrow and spleen) and non-hematopoietic organ (lungs and liver) for periods of up to 60 hours following infusion, however, the number of donor hematopoietic cells localized to bone marrow was more than that localized to non-hematopoietic organ (P < 0.05). These results indicated that there were also donor early hematopoietic cells in non-hematopoietic organ of recipients at the homing phase in allo-BMT mice.

Journal Article↗