Mammalian cell totipotency is a subject that has fascinated scientists for generations. A long lasting question whether some of the somatic cells retains totipotency was answered by the cloning of Dolly at the end of ...Mammalian cell totipotency is a subject that has fascinated scientists for generations. A long lasting question whether some of the somatic cells retains totipotency was answered by the cloning of Dolly at the end of the 20th century. The dawn of the 21st has brought forward great expectations in harnessing the power of totipotentcy in medicine. Through stem cell biology, it is possible to generate any parts of the human body by stem cell engineering. Considerable resources will be devoted to harness the untapped potentials of stem cells in the foreseeable future which may transform medicine as we know today. At the molecular level, totipotency has been linked to a singular transcription factor and its expression appears to define whether a cell should be totipotent. Named Oct4, it can activate or repress the expression of various genes. Curiously, very little is known about Oct4 beyond its ability to regulate gene expression. The mechanism by which Oct4 specifies totipotency remains entirely unresolved. In this review, we summarize the structure and function of Oct4 and address issues related to Oct4 function in maintaining totipotency or pluripotency of embryonic stem cells.展开更多
AIM： To evaluate the safety and feasibility of bone marrow cell （BMC） transplantation in patients with chronic liver disease on the waiting list for liver transplantation. METHODS： Ten patients （eight males） wit...AIM： To evaluate the safety and feasibility of bone marrow cell （BMC） transplantation in patients with chronic liver disease on the waiting list for liver transplantation. METHODS： Ten patients （eight males） with chronic liver disease were enrolled to receive infusion of autologous bone marrow-derived cells. Seven patients were classified as Child-Pugh B and three as Child-Pugh C. Baseline assessment included complete clinical and laboratory evaluation and abdominal MRI. Approximately 50 mL of bone marrow aspirate was prepared by centrifugation in a ficoll-hypaque gradient. At least of 100 millions of mononuclear-enriched BMCs were infused into the hepatic artery using the routine technique for arterial chemoembolization for liver tumors. Patients were followed up for adverse events up to 4 mo. RESULTS： The median age of the patients was 52 years （range 24-70 years）. All patients were discharged 48 h after BMC infusion. Two patients complained ofmild pain at the bone marrow needle puncture site. No other complications or specific side effects related to the procedure were observed. Bilirubin levels were lower at 1 （2.19 ± 0.9） and 4 mo （2.10 ± 1.0） after cell transplantation that baseline levels （238 ± 1.2）. Albumin levels 4 mo after BMC infusion （3.73 ± 0.5） were higher than baseline levels （3.47 ± 0.5）. International normalized ratio （INR） decreased from 1.48 （SD = 0.23） to 1.43 （SD = 0.23） one month after cell transplantation. CONCLUSION： BMC infusion into hepatic artery of patients with advanced chronic liver disease is safe and feasible. In addition, a decrease in mean serum bilirubin and INR levels and an increase in albumin levels are observed. Our data warrant further studies in order to evaluate the effect of BMC transplantation in patients with advanced chronic liver disease.展开更多
文摘Mammalian cell totipotency is a subject that has fascinated scientists for generations. A long lasting question whether some of the somatic cells retains totipotency was answered by the cloning of Dolly at the end of the 20th century. The dawn of the 21st has brought forward great expectations in harnessing the power of totipotentcy in medicine. Through stem cell biology, it is possible to generate any parts of the human body by stem cell engineering. Considerable resources will be devoted to harness the untapped potentials of stem cells in the foreseeable future which may transform medicine as we know today. At the molecular level, totipotency has been linked to a singular transcription factor and its expression appears to define whether a cell should be totipotent. Named Oct4, it can activate or repress the expression of various genes. Curiously, very little is known about Oct4 beyond its ability to regulate gene expression. The mechanism by which Oct4 specifies totipotency remains entirely unresolved. In this review, we summarize the structure and function of Oct4 and address issues related to Oct4 function in maintaining totipotency or pluripotency of embryonic stem cells.
基金Supported by IMBTMCT/CNPq and Monte Tabor/Hospital Sao Rafael
文摘AIM： To evaluate the safety and feasibility of bone marrow cell （BMC） transplantation in patients with chronic liver disease on the waiting list for liver transplantation. METHODS： Ten patients （eight males） with chronic liver disease were enrolled to receive infusion of autologous bone marrow-derived cells. Seven patients were classified as Child-Pugh B and three as Child-Pugh C. Baseline assessment included complete clinical and laboratory evaluation and abdominal MRI. Approximately 50 mL of bone marrow aspirate was prepared by centrifugation in a ficoll-hypaque gradient. At least of 100 millions of mononuclear-enriched BMCs were infused into the hepatic artery using the routine technique for arterial chemoembolization for liver tumors. Patients were followed up for adverse events up to 4 mo. RESULTS： The median age of the patients was 52 years （range 24-70 years）. All patients were discharged 48 h after BMC infusion. Two patients complained ofmild pain at the bone marrow needle puncture site. No other complications or specific side effects related to the procedure were observed. Bilirubin levels were lower at 1 （2.19 ± 0.9） and 4 mo （2.10 ± 1.0） after cell transplantation that baseline levels （238 ± 1.2）. Albumin levels 4 mo after BMC infusion （3.73 ± 0.5） were higher than baseline levels （3.47 ± 0.5）. International normalized ratio （INR） decreased from 1.48 （SD = 0.23） to 1.43 （SD = 0.23） one month after cell transplantation. CONCLUSION： BMC infusion into hepatic artery of patients with advanced chronic liver disease is safe and feasible. In addition, a decrease in mean serum bilirubin and INR levels and an increase in albumin levels are observed. Our data warrant further studies in order to evaluate the effect of BMC transplantation in patients with advanced chronic liver disease.
