BACKGROUND:The rapidly developed transplantation of peripheral blood stem cells have been successfully used to substitute bone marrow transplantation and become the first choice method for transplantation of hemopoietic stem cells.It is relatively difficult to collect peripheral blood stem cells from young age and low body mass infants.OBJECTIVE:To investigate the safety and adverse effects of peripheral blood stem cell collection from young age and low body mass through the use of blood cell separator.METHODS:Two type 1 diabetes mellitus infants,aged younger than 2 years old and with body mass less than 15 kg,were treated using autologous hemopoietic stem cell transplantation.The two infants were adequately comforted to lesion the fear of collection.At 1 week prior to collection,calcium agent was orally taken to reduce the incidences of low calcium.Within 24 hours prior to collection,oily food was forbidden,and on the day of collection,milk was forbidden,to avoid chylemia,which influences blood collection.Prior to collection,200 mL 25 Gy y-ray radiated red blood cells suspension was injected into the tube,which was routinely placed in the subclavian vein,to avoid hypovolaemic syndrome and the effects on hematocrit.Individualized collection parameters were set,During collection,blood circulation volume was 3,4 times of systemic blood circulation to ensure sufficient total circulation volume.During isolation,the ratio of ACD to whole blood was kept between 1:11 and 1:13 to prevent sodium citrate poisoning.RESULTS AND CONCLUSION:Peripheral blood stem cells were successfully collected during first intention in each infant.During collection,stable vital signs but no adverse effects were observed.After collection,mononuclear cells weighted 14.71×108/kg and 18.82×108/kg respectively,and CD34+ cells were about 34.13×108/kg and 32.38×106/kg,respectively in each infant.Therefore,it is feasible to collect peripheral blood stem cells from infants of young age and low body mass under sufficient psychological preparation.

Objective To investigate the effect of mitogen-activated protein kinase(MAPK)pathway on the transcriptional expression of mdr1 gene induced by doxorubicin ( DOX)and study the transcription regulation of mdr1 gene.Methods K562 cells were treated with DOX(0.01 μg/ml)with the initial concentration of 0.01 μg/ml for 24 hours,then change the culture media without DOX.K562 cells were cultured until the its status wag recovered.Subsequently the cells were treated with DOX(0.02μg/ml)for 24 hours again.The concentration of DOX was increaged until 0.05 μg/ml by following the protocol above.K562 cells were collected at the concentration of 0.01 μg/ml,0.03μg/ml and 0.05μS/ml DOX.Expression of mdr1 gene were examined by reverse transcription-polymerase chain reaction(RT-PCR).Pglycoprotein(P-gP)wag detected by flow cytometry.Western blot wag performed to detect ERK and P-ERk.K562 cells were pretreated with MAPK inhibitor PD98059 for 1 hour.and then DOX was added.RT-PCR and FCM were used to detect the expression of mdr1 mRNA and P-gp.Results When K562 cells were exposured to DOX.the phosphorylation of ERK wag increaged.the mdr1 gene wag highly expressed as well as its corresponding protein P-gp.When the concentration of DOX was 0.05μg/ml,the expression of mdr1 gene and P-gp were increased over 5 fold.When K562 cells were pretreated with MAPK inhibitor PD98059,the expression of mdr1 gene induced by DOX(the concentration was 0.03 μg/ml and 0.05 μg/m1)was effectively inhibited by(74.1±0.11)%and(70.2±0.14)%respectively.Conclusions DOX could induce the expression of mdr1 gene in K562 cells accompanied by the activation of MAPK/ERK pathway.The block of activation of ERK could inhibit the induced expression of mdr1 gene.