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The erythroid-enriched transcription factor NF-E2 is composed of two subunits, p45 and p18, the former of which is mainly expressed in the hematopoietic system. We have isolated and characterized the mouse p45 NF-E2 gene; we show here that, similar to the human gene, the mouse gene has two alternative promoters, which are differentially active during development and in different hematopoietic cells. Transcripts from the distal promoter are present in both erythroid and myeloid cells; however, transcripts from an alternative proximal 1b promoter, lying in the first intron, are abundant in erythroid cells, but barely detectable in myeloid cells. During development, both transcripts are detectable in yolk sac, fetal liver, and bone marrow. Transfection experiments show that proximal promoter 1b has a strong activity in erythroid cells, which is completely dependent on the integrity of a palindromic GATA-1 binding site. In contrast, the distal promoter 1a is not active in this assay. When the promoter 1b is placed 3' to the promoter 1a and reporter gene, in an arrangement that resembles the natural one, it acts as an enhancer to stimulate the activity of the upstream promoter la.

The transcription factor GATA‐1 is required for the normal development of erythroid cells. GATA‐1 is also expressed in other hemopoietic cells, suggesting that it might be initially activated in a multipotent progenitor. To immortalize GATA‐1‐expressing progenitors, we generated mice transgenic for a thermosensitive SV40 T gene, driven by the GATA‐1 promoter‐enhancer. Immortalized marrow cells grow in culture at 32 degrees C but not at 38 degrees C, and are dependent on erythropoietin (Epo) or interleukin 3 (IL‐3). Epo dependent cells express hemoglobin, high levels of GATA‐1, GATA‐2 and NF‐E2 p45 mRNAs, and are positive for stem cell antigen 2 (Sca‐2) and the early myeloid marker ER‐MP12. IL‐3 dependent cells can be derived from Epo dependent lines, and are hemoglobin‐, Sca‐2‐ and ER‐MP12‐negative, have low GATA‐1 and NF‐E2 p45 mRNA levels, and express myeloid markers Mac‐1, F4/80 and Gr‐1. Brief treatment of Epo dependent cells with myeloid growth factors (plus Epo) leads to the induction of Mac‐1, F4/80 and Gr‐1, concomitant with the disappearance from most cells of Sca‐2, ER‐MP12 and GATA‐1 driven T antigen nuclear expression. Thus, the immortalized Epo dependent cells have the property of a progenitor capable of differentiation towards either the erythroid or myeloid lineages. These cells initiate transcription of a proportion of GATA‐1 RNA molecules at an upstream promoter, previously known to be expressed only in testis cells.

Lignite may be hydrogenated to a Jow-sulfur, low-ash, heavy fuel oil in the absence of added catalysts by use of synthesis gas and the moisture in the coal as the reducing agent. Conversions of 90-94% and oil yields near 60% (moisture, ash-free basis) have been obtained routinely at temperatures of 425-450°C and pressures of 3000-4000 psig. These conversions and oil yields are higher than those obtained with hydrogen at the same conditions. The effectiveness of carbon monoxide in hydrogenating lignite is, in part, due to the presence of the carbonates of the alkali and alkaline earth metals which react with carbon monoxide, in the presence of water, yielding formates, the active reducing agents.

The transcription factor GATA‐1 is required for the normal development of erythroid cells. GATA‐1 is also expressed in other hemopoietic cells, suggesting that it might be initially activated in a multipotent progenitor. To immortalize GATA‐1‐expressing progenitors, we generated mice transgenic for a thermosensitive SV40 T gene, driven by the GATA‐1 promoter‐enhancer. Immortalized marrow cells grow in culture at 32 degrees C but not at 38 degrees C, and are dependent on erythropoietin (Epo) or interleukin 3 (IL‐3). Epo dependent cells express hemoglobin, high levels of GATA‐1, GATA‐2 and NF‐E2 p45 mRNAs, and are positive for stem cell antigen 2 (Sca‐2) and the early myeloid marker ER‐MP12. IL‐3 dependent cells can be derived from Epo dependent lines, and are hemoglobin‐, Sca‐2‐ and ER‐MP12‐negative, have low GATA‐1 and NF‐E2 p45 mRNA levels, and express myeloid markers Mac‐1, F4/80 and Gr‐1. Brief treatment of Epo dependent cells with myeloid growth factors (plus Epo) leads to the induction of Mac‐1, F4/80 and Gr‐1, concomitant with the disappearance from most cells of Sca‐2, ER‐MP12 and GATA‐1 driven T antigen nuclear expression. Thus, the immortalized Epo dependent cells have the property of a progenitor capable of differentiation towards either the erythroid or myeloid lineages. These cells initiate transcription of a proportion of GATA‐1 RNA molecules at an upstream promoter, previously known to be expressed only in testis cells.

The laparoscopic resection of gastric stromal tumors is being performed with increased frequency. Wedge resection of anterior wall lesions is generally performed. The treatment of posterior wall lesions is still controversial.We report three cases of gastric submucosal tumors treated by a laparoscopic wedge resection of the stomach. All lesions were localized anterior gastric wall by intraoperative ultrasound on the. In the first patient the resection was performed with an endoscopic stapler; in the other patients, ultrasonic coagulation in association with an intracorporeal suture has been used.All patients were successfully treated laparoscopically; there were no conversions to open surgery. In all cases the operative course was uneventful. The postoperative hospital stay ranged from 6 to 8 days.The results suggest that laparoscopic surgery is an adequate strategy for gastric submucosal neoplasms including gastrointestinal stromal tumors (GIST). Intraoperative ultrasound is very useful in the selection of the technical approach with or without the endoscopic stapler.