BACKGROUND: We have developed a novel system for expansion of gene-modified hematopoietic stem/progenitor cells to overcome the low efficiency of current gene transfer methodology. This system involves 'selective amplifier genes', that encode fusion proteins between the granulocyte colony-stimulating factor receptor (GCR) and the hormone-binding domain of estrogen receptor (ER). Hematopoietic progenitors expressing the chimeras showed estrogen-responsive growth in a controllable manner. However, endogenous estrogen may activate the fusion proteins in vivo, depending on the hormonal status of the subjects. METHODS: We replaced ER with a mutant receptor (TmR) which specifically binds to 4-hydroxytamoxifen (Tm), to overcome limitations with wild-type ER. Interleukin-3 (IL-3)-dependent Ba/F3 cells and hematopoietic progenitor cells transduced with the resultant fusion proteins (GCRTmR and delta GCRTmR) were examined for ligand-inducible growth. RESULTS: GCRTmR- and delta GCRTmR-expressing Ba/F3 showed IL-3-independent growth in response to Tm, while the cells were unresponsive to estrogen at concentrations up to 10(-7)-10(-6) M. Furthermore, murine bone marrow cells transduced with GCRTmR and delta GCRTmR formed colonies in methyl-cellulose medium in response to Tm, while virtually no colonies appeared with 10(-7) M estrogen or without cytokines. CONCLUSIONS: These results suggest that influences of the endogenous estrogen can be almost eliminated by using the GCRTmR/Tm or delta GCRTmR/Tm system to expand gene-modified hematopoietic stem/progenitor cells.

Animals↗

PubMedDate not supplied

Congestive heart failure during early infancy in patients with ventricular septal defect relative to early closure.

The hemodynamic features of 44 patients requiring surgical closure of a ventricular septal defect (VSD) during early infancy were evaluated. The VSD was closed within the first 6 months of life in 29 patients (group A) and during the second 6 months in 15 patients (group B). The left-to-right (L-R) shunts were significantly greater in group A than in group B, although in all patients they were more than 50%. In contrast, the left ventricular end-diastolic volume was significantly greater in group B than in group A, whereas the right ventricular end-diastolic volume was greater in group A; the difference was not statistically significant. The step-up in blood oxygen saturation in the lower right atrium, which was significantly more in group A, indicated the L-R shunt across the patent foramen ovale (PFO). The L-R shunt across the VSD during diastole was also detected in all patients angiographically. With early infantile VSD, the larger the L-R shunt the greater was the likelihood of early surgery. Right ventricular volume overload caused by the L-R shunt across a PFO as well as through the VSD during diastole is a useful indicator of a large shunt in infants with VSD.

Female↗

PubMedDate not supplied

A case of anomalous origin of the pulmonary arteries: right pulmonary artery from the descending aorta and the left pulmonary artery from the ascending aorta.

A 3-month-old girl classified as having persistent truncus arteriosus underwent surgical correction of the anomalous origin of the pulmonary arteries; the right pulmonary artery from the descending aorta and the left pulmonary artery from the ascending aorta. The patient died on the fourth postoperative day. The definite diagnosis and choice of surgical strategies should be further examined.

Abnormalities, Multiple↗