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Dihydrofolate reductase (DHFR) and thymidylate synthase (TS) are crucial enzymes in DNA synthesis. In alveolata both enzymes are expressed as one bifunctional enzyme.', "Loss of this essential enzyme activities after successful allelic assortment of knock out alleles yields an auxotrophic marker in ciliates. Here the cloning, characterisation and functional analysis of Tetrahymena thermophila's DHFR-TS is presented. A first aspect of the presented work relates to destruction of DHFR-TS enzyme function in an alveolate thereby causing an auxotrophy for thymidine. A second aspect is to knock in an expression cassette encoding for a foreign gene with subsequent expression of the target protein.
Does the bifunctional dihydrofolate reductase thymidylate synthase of Tetrahymena thermophila provide a tool for molecular and biotechnology applications?

Fractional CO2 laser has recently emerged as a promising therapeutic modality to improve the texture and appearance of burn scars. An issue in many burn scars is persistent erythema, which traditionally has been treated with vascular lasers. Interestingly, fractional CO2 lasers have been shown to improve the appearance of burn scars, including erythema, but no mechanism has been proposed for this change. Our objective is to evaluate the histopathologic changes in vasculature in burn scars treated with fractionated CO2 laser, and to attempt to describe the mechanism behind reduced erythema following treatment.', 'Uncontrolled, prospective study of ten patients with mature burn scars, from a clinical and histological perspective. Biopsy specimens were obtained before and 2 months after 3 treatment sessions. Anti-CD31 immunostaining was performed to highlight vascular patterns in biopsy specimens.', 'In histological analysis, an increase in vascular density, particularly of small caliber vessels, was seen following treatment, with an 82.6% average increase in vasculature (P=0.028). This increase in vascularity correlated with a decrease in clinical erythema and vascularity scores, measured using the Vancouver Scar Scale.
Do vascular patterns in mature hypertrophic burn scars treated with fractional CO2 laser?

Acute rejection (AR) after organ transplantation results in transplant arteriosclerosis (TA). Endothelial progenitor cells (EPCs) are involved in tissue repair and blood vessel formation but are suspected to be a cause of TA.', 'In this study, we introduced a syngeneic and allogeneic abdominal aortic transplant model with C57BL/6 and BALB/c mice. Syngeneic and allogeneic grafts were histopathologically analyzed after transplantation. Bone marrow-derived EPCs were injected into transplant model animals to observe their distribution and temporal concentration changes. Changes of vascular endothelial growth factor receptor 1 (VEGFR-1), phosphorylated VEGFR-1 (pVEGFR-1), VEGFR-2, pVEGFR-2, protein kinase B (Akt), pAkt, extracellular signal-regulated kinase 1 (Erk1), pErk1 levels in EPCs upon VEGF165 and the VEGFR inhibitor Vandetanib exposure were analyzed invitro with western blotting.', 'In the allogeneic transplant group, two weeks after transplantation, formations of new intima layers could be observed, and its proliferation gradually increased to four and six weeks post-transplantation (p<0.05), accompanied by significant arterial stenoses. Exogenous EPCs mainly localized to the damaged sites of the transplant arteries. Invivo, Vandetanib caused a significant dose dependent decrease of transplant hyperplasia (p<0.05) and inhibited VEGF related proliferation, migration and adhesion of EPCs.
Do endothelial progenitor cells induce transplant arteriosclerosis via VEGFR-1/2 activity?