The purpose of this study is to determine the effects of low-dose radiation on fibroblast cells irradiated by spectrally and dosimetrically well-characterized soft x-rays. To achieve this, a new cell ...culture x-ray irradiation system was designed. This system generates characteristic fluorescent x-rays to irradiate the cell culture with x-rays of well-defined energies and doses. 3T3 fibroblast cells were cultured in cups with Mylar® surfaces and were irradiated for one hour with characteristic iron (Fe) K x-ray radiation at a dose rate of approximately 550 μGy/hr. Cell proliferation, total protein analysis, flow cytometry, and cell staining were performed on fibroblast cells to determine the various effects caused by the radiation. Irradiated cells demonstrated increased proliferation and protein production compared to control samples. Flow cytometry revealed that a higher percentage of irradiated cells were in the G0/G1 phase of the cell cycle compared to control counterparts, which is consistent with other low-dose studies. Cell staining results suggest that irradiated cells maintained normal cell functions after radiation exposure, as there were no qualitative differences between the images of the control and irradiated samples. The result of this study suggest that low-dose soft x-ray radiation might cause an initial pause, followed by a significant increase, in proliferation. An initial "pause" in cell proliferation could be a protective mechanism of the cells to minimize DNA damage caused by radiation exposure. The new cell irradiation system developed here allows for unprecedented control over the properties of the x-rays given to the cell cultures. This will allow for further studies on various cell types with known spectral distribution and carefully measured doses of radiation, which may help to elucidate the mechanisms behind varied cell responses to low-dose x-rays reported in the literature.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Heparan sulfate (HS) and chondroitin sulfate (CS) are two structurally distinct natural polysaccharides. Here, we report the synthesis of a library of seven structurally homogeneous HS and CS ...chimeric dodecasaccharides (12-mers). The synthesis was accomplished using six HS biosynthetic enzymes and four CS biosynthetic enzymes. The chimeras contain a CS domain on the reducing end and a HS domain on the nonreducing end. The synthesized chimeras display anticoagulant activity as measured by both in vitro and ex vivo experiments. Furthermore, the anticoagulant activity of H/C 12-mer 5 is reversible by protamine, a U.S. Food and Drug Administration-approved polypeptide to neutralize anticoagulant drug heparin. Our findings demonstrate the synthesis of unnatural HS-CS chimeric oligosaccharides using natural biosynthetic enzymes, offering a new class of glycan molecules for biological research.
Postmastectomy radiation therapy (PMRT) delivered to an immediate reconstruction increases the risk of surgical complications. Although acellular dermal matrix (ADM) has been used with immediate ...tissue expander (TE) reconstruction to improve cosmetic outcomes and minimize capsular contracture, there is a paucity of data on this approach in the setting of PMRT.
Thirty-two patients with stage I to III breast cancer were treated with mastectomy, immediate TE-ADM reconstruction, and PMRT between 2009 and 2012 in a prospective single-arm study. The primary objective was the "success" rate, determined by the number of patients at 2 years after PMRT having an intact final reconstruction, no major complications, and a cosmetic outcome rated by a physician as excellent or good.
The median follow-up was 24 months. Final reconstruction status was known in 31 of 32 patients (96.9%; 1 patient left the country) and completed in 29 of 31 patients (93.5%; implant, n = 26; flap, n = 1; both, n = 2; none, n = 2). At 2 years, 6 patients were unevaluable (metastatic disease, n = 3; withdrawn consent, n = 1; left the country, n = 2). Of 26 evaluable patients, the success rate was 65.4% (17 of 26). Lack of success was the result of "fair" cosmesis (n = 2), infection (n = 2), severe capsular contracture (n = 1), major revision (n = 2), and no final reconstruction (n = 2). Most patients had good-to-excellent 2-year overall cosmesis based on patient perception (15; 62.5%) and physician evaluation (19; 79.2%).
To the best of our knowledge, this is the first dedicated prospective trial evaluating long-term cosmetic and complication outcomes in patients treated with immediate TE-ADM reconstruction followed by PMRT. Most patients (65.4%) met the success criteria in this prospective single-arm series. The great majority (93.5%) achieved final reconstruction; most had good-to-excellent overall cosmetic outcomes (79.2%). The results with longer follow-up will be of interest, and further investigation of strategies to optimize reconstruction with PMRT are warranted.
A variety of genetic techniques have been devised to determine cell lineage relationships during tissue development. Some of these systems monitor cell lineages spatially and/or temporally without ...regard to gene expression by the cells, whereas others correlate gene expression with the lineage under study. The
AL4
echnique for
eal-time
nd
lonal
xpression (G-TRACE) system allows for rapid, fluorescent protein-based visualization of both current and past GAL4 expression patterns and is therefore amenable to genome-wide expression-based lineage screens. Here we describe the results from such a screen, performed by undergraduate students of the University of California, Los Angeles (UCLA) Undergraduate Research Consortium for Functional Genomics (URCFG) and high school summer scholars as part of a discovery-based education program. The results of the screen, which reveal novel expression-based lineage patterns within the brain, the imaginal disc epithelia, and the hematopoietic lymph gland, have been compiled into the G-TRACE Expression Database (GED), an online resource for use by the
research community. The impact of this discovery-based research experience on student learning gains was assessed independently and shown to be greater than that of similar programs conducted elsewhere. Furthermore, students participating in the URCFG showed considerably higher STEM retention rates than UCLA STEM students that did not participate in the URCFG, as well as STEM students nationwide.
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