Reproducible doxycycline-inducible transgene expression at specific loci generated by Cre-recombinase mediated cassette exchange

Comparative analysis of mutants using transfection is complicated by clones exhibiting variable levels of gene expression due to copy number differences and genomic position effects. Recombinase-mediated cassette exchange (RMCE) can overcome these problems by introducing the target gene into pre-determined chromosomal loci, but recombination between the available recombinase targeting sites can reduce the efficiency of targeted integration. We developed a new LoxP site (designated L3), which when used with the original LoxP site (designated L2), allows highly efficient and directional replacement of chromosomal DNA with incoming DNA. A total of six independent LoxP integration sites introduced either by homologous recombination or retroviral delivery were analyzed; 70–80% of the clones analyzed in hamster and human cells were correct recombinants. We combined the RMCE strategy with a new, tightly regulated tetracycline induction system to produce a robust, highly reliable system for inducible transgene expression. We observed stable inducible expression for over 1 month, with uniform expression in the cell population and between clones derived from the same integration site. This system described should find significant applications for studies requiring high level and regulated transgene expression and for determining the effects of various stresses or oncogenic conditions in vivo and in vitro

Effect of volume reduction on lung transplant timing and selection for chronic obstructive pulmonary disease

AbstractBackground: End-stage chronic obstructive pulmonary disease has traditionally been treated with lung transplantation. For 2 years, our lung transplantation program has placed patients with appropriate criteria for lung transplantation and volume reduction into a prospective management algorithm. These patients are offered the lung volume reduction option as a “bridge” to “extend” the eventual time to transplantation. We examine the results of this pilot program. Methods: From October 11, 1993, to April 17, 1997, 31 patients were evaluated for lung transplantation who also had physiologic criteria for volume reduction (forced expiratory volume in 1 second ≤ 25%; residual volume > 200%; significant ventilation/perfusion heterogeneity). All patients completed 6 weeks of pulmonary rehabilitation and then had baseline pulmonary function and 6-minute walk tests. These patients were then offered volume reduction as a “bridge” and were simultaneously listed for transplantation. Postoperatively, these 31 patients were then divided into two groups: Those with satisfactory results at 4 to 6 months after volume reduction and those with unsatisfactory results. Volume reduction was performed through a video thoracic approach in 87% of the patients and bilateral median sternotomy in the remaining 13%. The condition of the patients was monitored after the operation with repeated pulmonary function tests and 6-minute walk tests at 3-month intervals. Results: Twenty-four of 31 patients (77.4%) had primary success (at 4 to 6 months) results after lung volume reduction and 7 patients (22.6%) had primary failure, including 1 patient who died in the perioperative period (3.2%). Four patients (16.7%) from the primary success cohort had significant deterioration in their pulmonary function during intermediate-term follow-up and were then reconsidered for lung transplantation. Two of them have subsequently undergone transplantation with good postoperative pulmonary function results. Interestingly, three patients had α1-antitrypsin deficiency; two had a poor outcome of lung volume reduction and primary failure. Conclusions: Lung volume reduction in these patients is safe. Seventy-seven percent of otherwise suitable candidates for lung transplantation achieved initial good results from volume reduction and were deactivated from the list (placed on status 7). Most patients entering our prospective management algorithm have either significantly delayed or completely avoided lung transplantation after volume reduction. Lung volume reduction has substantially affected the practice, timing, and selection of patients for lung transplantation. Our waiting list now has a reduced percentage of patients with a diagnosis of chronic obstructive pulmonary disease compared with 3 years ago. Our experience suggests that lung volume reduction may be limited as a “bridge” in α1-antitrypsin deficiency. (J Thorac Cardiovasc Surg 1998;115:9-18

Stimulated stromal cells induce gamma-globin gene expression in erythroid cells via nitric oxide production

Objective. We have previously shown that nitric oxide (NO) is involved in the hydroxyurea-induced increase of gamma-globin gene expression in cultured human erythroid progenitor cells and that hydroxyurea increases NO production in endothelial cells via endothelial NO synthase (NOS). We have now expanded those studies to demonstrate that stimulation of gamma-globin gene expression is also mediated by NOS induction in stromal cells within the bone marrow microenvironment. Materials and Methods. Using NO analyzer, we measured NO production in endothelial and macrophage cell cultures. In coculture studies of erythroid and stromal cells, we measured globin gene expression during stimulation by NO induers. Results. Hydroxyurea (30 - 100 mu M) induced NOS-dependent production of NO in human macrophages (up to 1.2 mu M). Coculture studies of human macrophages with erythroid progenitor cells also resulted in induction of gamma-globin mRNA expression (up to threefold) in the presence of hydroxyurea. NOS-dependent stimulation of NO by lipopolysaccharide (up to 0.6 mu M) has been observed in human macrophages. We found that lipopolysaccharide and interferon-gamma together increased gamma-globin gene expression (up to twofold) in human macrophage/erythroid cell cocultures. Coculture of human bone marrow endothelial cells with erythroid progenitor cells also induced gamma-globin mRNA expression (2.4-fold) in the presence of hydroxyurea (40 mu M). Conclusion. These results demonstrate an arrangement by which NO and fetal hemoglobin inducers may stimulate globin genes in erythroid cells via the common paracrine effect of bone marrow stromal cells

Predictive factor for the response to adjuvant therapy with emphasis in breast cancer

One of the major challenges of early-stage breast cancer is to select the adjuvant therapy that ensures the most benefits and the least harm for the patient. The definition of accurate predictive factors is therefore of paramount importance. So far the choice of adjuvant therapy has been based on the number of affected lymph nodes and the hormone receptor status of the patient. This paper evaluates the use of other tumor-related markers as predictive factors for adjuvant therapy. These include HER2, p53 and Bcl-2, cathepsin B, p27, proliferating cell nuclear antigen (PCNA), cyclin D, Ki-67, and vascular endothelial growth factor (VEGF)

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure