1,835 research outputs found

    The Relation between Galaxy Structure and Spectral Type: Implications for the Buildup of the Quiescent Galaxy Population at 0.5<z<2.0

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    We present the relation between galaxy structure and spectral type, using a K-selected galaxy sample at 0.5<z<2.0. Based on similarities between the UV-to-NIR spectral energy distributions, we classify galaxies into 32 spectral types. The different types span a wide range in evolutionary phases, and thus -- in combination with available CANDELS/F160W imaging -- are ideal to study the structural evolution of galaxies. Effective radii (R_e) and Sersic parameters (n) have been measured for 572 individual galaxies, and for each type, we determine R_e at fixed stellar mass by correcting for the mass-size relation. We use the rest-frame U-V vs. V-J diagram to investigate evolutionary trends. When moving into the direction perpendicular to the star-forming sequence, in which we see the Halpha equivalent width and the specific star formation rate (sSFR) decrease, we find a decrease in R_e and an increase in n. On the quiescent sequence we find an opposite trend, with older redder galaxies being larger. When splitting the sample into redshift bins, we find that young post-starburst galaxies are most prevalent at z>1.5 and significantly smaller than all other galaxy types at the same redshift. This result suggests that the suppression of star formation may be associated with significant structural evolution at z>1.5. At z<1, galaxy types with intermediate sSFRs (10^{-11.5}-10^{-10.5} yr^-1) do not have post-starburst SED shapes. These galaxies have similar sizes as older quiescent galaxies, implying that they can passively evolve onto the quiescent sequence, without increasing the average size of the quiescent galaxy population.Comment: 7 pages, 5 figures; Accepted for publication in ApJ

    Traditional Chinese medicine herbal mixture LQ arrests FUCCI-expressing HeLa cells in G₀/G₁ phase in 2D plastic, 2.5D Matrigel, and 3D Gelfoam culture visualized with FUCCI imaging.

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    We used the fluorescence ubiquitination-based cell cycle indicator (FUCCI) to monitor cell cycle arrest after treatment of FUCCI-expressing HeLa cells (FUCCI-HeLa) with a traditional Chinese medicine (TCM) herbal mixture LQ, previously shown to have anti-tumor and anti-metastatic activity in mouse models. Paclitaxel was used as the positive control. In 2D monolayer culture, the untreated control had approximately 45% of the cells in S/G₂/M phase. In contrast, the LQ-treated cells (9 mg/ml) were mostly in the G₀/G₁ (&gt;90%) after 72 hours. After treatment with paclitaxel (0.01 ÎŒm), for 72 hours, 95% of the cells were in S/G₂/M. In 2.5D Matrigel culture, the colonies in the untreated control group had 40% of the cells in S/G₂/M. LQ arrested the cells in G₀/G₁ after 72 hours. Paclitaxel arrested almost all the cells in S/G₂/M after 72 hours. In 3D Gelfoam culture, the untreated control culture had approximately 45% of cells in G₂/M. In contrast, the LQ-treated cells were mostly in G₀/G₁ phase (&gt;80%) after 72 hours treatment. Paclitaxel resulted in 90% of the cells arrested in S/G₂/M after 72 hours. The present report suggests the non-toxic LQ has potential to maintain cancers in a quiescent state for long periods of time

    Selective methioninase-induced trap of cancer cells in S/G2 phase visualized by FUCCI imaging confers chemosensitivity.

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    A major impediment to the response of tumors to chemotherapy is that the large majority of cancer cells within a tumor are quiescent in G0/G1, where cancer cells are resistant to chemotherapy. To attempt to solve this problem of quiescent cells in a tumor, cancer cells were treated with recombinant methioninase (rMETase), which selectively traps cancer cells in S/G2. The cell cycle phase of the cancer cells was visualized with the fluorescence ubiquitination-based cell cycle indicator cell cycle indicator (FUCCI). At the time of rMETase-induced S/G2-phase blockage, identified by the cancer cells' green fluorescence by FUCCI imaging, the cancer cells were administered S/G2-dependent chemotherapy drugs, which interact with DNA or block DNA synthesis such as doxorubicin, cisplatin, or 5-fluorouracil. Treatment of cancer cells with drugs only, without rMETase-induced S/G2 phase blockage, led to the majority of the cancer-cell population being blocked in G0/G1 phase, identified by the cancer cells becoming red fluorescent in the FUCCI system. The G0/G1 blocked cells were resistant to the chemotherapy. In contrast, trapping of cancer cells in S/G2 phase by rMETase treatment followed by FUCCI-imaging-guided chemotherapy was highly effective in killing the cancer cells

    Simplification or elaboration? The Effects of Two Types of Text Modifications on Foreign Language Reading Comprehension

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    Linguistic simplification of written texts can increase their comprehensibility for non-native speakers, but reduce their utility for language learning in other ways, e.g. through the removal of linguistic items that learners do not know but need to learn. A study was conducted to test the hypothesis that some elaborative modifications observed in oral foreigner talk discourse, where redundancy and explicitness compensate for unknown linguistic items, offer a potential alternative approach to written text modification. 13 reading passages were presented to 483 Japanese college students in one of three forms: native baseline, simplified or elaborated. Comprehension, assessed by 30 multiple-choice test items, was highest among subjects reading the simplified version, but not significantly better than among those reading the elaborated version. The type of modifications to the texts interacted significantly with the kind of task used to assess comprehension: replication, synthesis or inference, suggesting that different kinds of text modification facilitate different levels of comprehension

    Adenoviral targeting of malignant melanoma for fluorescence-guided surgery prevents recurrence in orthotopic nude-mouse models.

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    Malignant melanoma requires precise resection in order to avoid metastatic recurrence. We report here that the telomerase-dependent, green fluorescent protein (GFP)-containing adenovirus OBP-401 could label malignant melanoma with GFP in situ in orthotopic mouse models. OBP-401-based fluorescence-guided surgery (FGS) resulted in the complete resection of malignant melanoma in the orthotopic models, where conventional bright-light surgery (BLS) could not. High-dose administration of OBP-401 enabled FGS without residual cancer cells or recurrence, due to its dual effect of cancer-cell labeling with GFP and killing

    Precise navigation surgery of tumours in the lung in mouse models enabled by in situ fluorescence labelling with a killer-reporter adenovirus.

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    BackgroundCurrent methods of image-guided surgery of tumours of the lung mostly rely on CT. A sensitive procedure of selective tumour fluorescence labelling would allow simple and high-resolution visualisation of the tumour for precise surgical navigation.MethodsHuman lung cancer cell lines H460 and A549 were genetically transformed to express red fluorescent protein (RFP). Tumours were grown subcutaneously for each cell line and harvested and minced for surgical orthotopic implantation on the left lung of nude mice. Tumour growth was measured by fluorescence imaging. After the tumours reached 5 mm in diameter, they were injected under fluorescence guidance with the telomerase-dependent green fluorescent protein (GFP)-containing adenovirus, OBP-401. Viral labelling of the lung tumours with GFP precisely colocalised with tumour RFP expression. Three days after administration of OBP-401, fluorescence-guided surgery (FGS) was performed.ResultsFGS of tumours in the lung was enabled by labelling with a telomerase-dependent adenovirus containing the GFP gene. Tumours in the lung were selectively and brightly labelled. FGS enabled complete lung tumour resection with no residual fluorescent tumour.ConclusionsFGS of tumours in the lung is feasible and more effective than bright-light surgery

    Tumor-targeting adenovirus OBP-401 inhibits primary and metastatic tumor growth of triple-negative breast cancer in orthotopic nude-mouse models.

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    Our laboratory previously developed a highly-invasive, triple-negative breast cancer (TNBC) variant using serial orthotopic implantation of the human MDA-MB-231 cell line in nude mice. The isolated variant was highly-invasive in the mammary gland and lymphatic channels and metastasized to lymph nodes in 10 of 12 mice compared to 2 of 12 of the parental cell line. In the present study, the tumor-selective telomerase dependent OBP-401 adenovirus was injected intratumorally (i.t.) (1 × 108 PFU) when the high-metastatic MDA-MB-231 primary tumor expressing red fluorescent protein (MDA-MB-231-RFP) reached approximately 500 mm3 (diameter; 10 mm). The mock-infected orthotopic primary tumor grew rapidly. After i.t. OBP-401 injection, the growth of the orthotopic tumors was arrested. Six weeks after implantation, the fluorescent area and fluorescence intensity showed no increase from the beginning of treatment. OBP-401 was then injected into high-metastatic MDA-MB-231-RFP primary orthotopic tumor growing in mice which already had developed metastasis within lymphatic ducts. All 7 of 7 control mice subsequently developed lymph node metastasis. In contrast, none of 7 mice which received OBP-401 had lymph node metastasis. Seven of 7 control mice also had gross lung metastasis. In contrast, none of the 7 mice which received OBP-401 had gross lung metastasis. Confocal laser microscopy imaging demonstrated that all control mice had diffuse lung metastases. In contrast, all 7 mice which received OBP-401 only had a few metastatic cells in the lung. OBP-401 treatment significantly extended survival of the treated mice

    Fluorescence-guided surgery of a highly-metastatic variant of human triple-negative breast cancer targeted with a cancer-specific GFP adenovirus prevents recurrence.

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    We have previously developed a genetically-engineered GFP-expressing telomerase-dependent adenovirus, OBP-401, which can selectively illuminate cancer cells. In the present report, we demonstrate that targeting a triple-negative high-invasive human breast cancer, orthotopically-growing in nude mice, with OBP-401 enables curative fluorescence-guided surgery (FGS). OBP-401 enabled complete resection and prevented local recurrence and greatly inhibited lymph-node metastasis due to the ability of the virus to selectively label and subsequently kill cancer cells. In contrast, residual breast cancer cells become more aggressive after bright (white)-light surgery (BLS). OBP-401-based FGS also improved the overall survival compared with conventional BLS. Thus, metastasis from a highly-aggressive triple-negative breast cancer can be prevented by FGS in a clinically-relevant mouse model
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