Aims. This study aims to elucidate a possible link between chemical properties of ices in star-forming regions and environmental characteristics (particularly metallicity) of the host galaxy. The ...Large Magellanic Cloud (LMC) is an excellent target to study properties of interstellar and circumstellar medium in a different galactic environment thanks to its proximity and low metallicity. Methods. We performed near-infrared, L-band spectroscopic observations toward embedded high-mass young stellar objects (YSOs) in the LMC with the Infrared Spectrometer And Array Camera (ISAAC) at the Very Large Telescope. The 3.2–3.7 μm spectral region, which is accessible from ground-based telescopes, is important for ice studies, since various C–H stretching vibrations of carbon bearing species fall in this region. Results. We obtained medium-resolution (R ~ 500) spectra in the 3–4 μm range for nine high-mass YSOs in the LMC. Additionally, we analyzed archival ISAAC data of two LMC YSOs. We detected absorption bands due to solid H2O and CH3OH as well as the 3.47 μm absorption band. The properties of these bands are investigated based on comparisons with Galactic embedded sources. The 3.53 μm CH3OH ice absorption band for the LMC YSOs is found to be absent or very weak compared to that seen toward Galactic sources. The absorption band is weakly detected for two out of eleven objects. We estimate the abundance of the CH3OH ice, which suggests that solid CH3OH is less abundant for high-mass YSOs in the LMC than those in our Galaxy. The 3.47 μm absorption band is detected toward six out of eleven LMC YSOs. We found that the 3.47 μm band and the H2O ice band correlate similarly between the LMC and Galactic samples, but the LMC sources seem to require a slightly higher H2O ice threshold for the appearance of the 3.47 μm band. For the LMC sources with relatively large H2O ice optical depths, we found that the strength ratio of the 3.47 μm band relative to the water ice band is only marginally lower than those of the Galactic sources. Conclusions. We propose that grain surface reactions at a relatively high dust temperature (warm ice chemistry) are responsible for the observed characteristics of ice chemical compositions in the LMC; i.e., the low abundance of solid CH3OH presented in this work as well as the high abundance of solid CO2 reported in previous studies. We suggest that this warm ice chemistry is one of the important characteristics of interstellar and circumstellar chemistry in low metallicity environments. The low abundance of CH3OH in the solid phase implies that formation of complex organic molecules from methanol-derived species is less efficient in the LMC. For the 3.47 μm band, the observed difference in the water ice threshold may suggest that a more shielded environment is necessary for the formation of the 3.47 μm band carrier in the LMC. On the one hand, in well-shielded regions of the LMC, our results suggest that the lower metallicity and different interstellar environment of the LMC have little effect on the abundance ratio of the 3.47 μm band carrier and water ice.
We have previously demonstrated in an in vitro study that Snail increased the invasion activity of hepatoma cells by upregulating matrix metalloproteinase (MMP) gene expression. In the present study, ...we examined whether Snail gene expression correlates with cancer invasion and prognosis of patients with hepatocellular carcinoma (HCC). Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed to evaluate Snail, E-cadherin, and MMP mRNA expressions in eight nodule-in-nodule tumours and 47 ordinary HCC tissues. In the nodule-in-nodule tumours, Snail expression significantly increased with tumour dedifferentiation (P=0.047). In the ordinary HCC tissues, Snail expression was significantly correlated with portal vein invasion (P=0.035) and intrahepatic metastasis (P=0.050); it also showed a significant correlation with MT1-MMP expression (r=0.572, P<0.001). In recurrence-free survival, the group with high Snail expression showed significantly poorer prognosis (P=0.035). Moreover, high Snail expression was an independent risk factor for early recurrence after curative resection. During the progression of HCC, Snail expression may be induced and accelerate invasion activity by upregulating MMP expression, resulting in portal invasion, intrahepatic metastasis, and poor prognosis.
Aims
We evaluated the cytokeratin profile of intrahepatic cholangiocarcinoma with respect to its histological classification and intrahepatic location (peripheral vs. hilar), and compared its profile ...with that of a variety of metastatic adenocarcinomas in liver.
Methods and results
Expression of cytokeratins 7, 8, 18, 19 and 20 was immunohistochemically examined in intrahepatic cholangiocarcinoma (n = 77) and metastatic adenocarcinoma in liver (21 colorectal, 14 gastric, three gallbladder and three pancreatic cancers). Materials were autopsy or surgical specimens. Cytokeratins 7, 8, 18 and 19 were expressed in 75 (97%), 75 (97%), 59 (77%) and 71 (92%) cases of intrahepatic cholangiocarcinoma, respectively. Moderate and extensive expression of cytokeratin 18 was more frequent in the peripheral than in the hilar type. Moderate and extensive expression of cytokeratin 19 was seen in almost all cases of well‐differentiated intrahepatic cholangiocarcinomas, while expression was decreased relatively in the moderately and decreased more in the poorly differentiated cases. While cytokeratin 20 was not found in non‐neoplastic biliary epithelia or in well‐differentiated intrahepatic cholangiocarcinomas, this cytokeratin was occasionally detectable in moderately and poorly differentiated intrahepatic cholangiocarcinomas and its expression was more frequent in the hilar type. Cytokeratin 20 expression was observed in 17 (81%) of metastatic adenocarcinomas in liver from colorectal regions, to a lesser degree in those from gastric regions, and was rare in those from gallbladder and pancreatic regions; cytokeratin 7 showed a reverse expression pattern in these metastatic adenocarcinomas in liver. The profile of cytokeratins 7 and 20 of metastatic colorectal and gastric carcinomas differed from that for intrahepatic cholangiocarcinomas, while that of metastatic gallbladder and pancreatic carcinoma was similar to that for intrahepatic cholangiocarcinomas. Moreover, cytokeratin 18 and 19 expression was significantly infrequent in metastatic gastric carcinomas than in intrahepatic cholangiocarcinomas and metastatic colorectal carcinomas.
Conclusion
The combined immunostaining of cytokeratins 7, 18, 19 and 20 is useful for the characterization of intrahepatic cholangiocarcinomas with respect to histological subtypes and intrahepatic location. It helps to differentiate intrahepatic cholangiocarcinoma from metastatic adenocarcinomas in liver and from colorectal and gastric regions; it also indicates the primary focus metastatic adenocarcinomas in livers.
This study investigates the temporal evolution of the infrared emission from the dusty nova V1280 Sco over 2000 days from the outburst. We have revealed that the infrared spectral energy ...distributions at 1272, 1616 and 1947 days are explained by the emissions produced by amorphous carbon dust of mass (6.6-8.7) × 10-8 Mʘ with a representative grain size of 0.01 µm and astronomical silicate dust of mass (3.4-4.3) × 10-7 Mʘ with a representative grain size of 0.3-0.5 µm. Both of carbon and silicate dust travel farther away from the white dwarf without an apparent mass evolution throughout those later epochs.
Intraductal papillary neoplasia of the liver (IPN-L) was recently proposed as the name for intraductal papillary proliferation of neoplastic biliary epithelium with a fine fibrovascular stalk ...resembling intraductal papillary mucinous neoplasm of the pancreas. We histochemically and immunohistochemically examined IPN-L alone or associated with hepatolithiasis, with an emphasis on the gastrointestinal metaplasia, nuclear p53 expression, and histologic progression. A total of 66 cases of IPN-L were divided into 4 groups: group 1, IPN-L with low-grade dysplasia (13 cases); group 2, IPN-L with high-grade dysplasia (20 cases); group 3, IPN-L lined with carcinoma in situ and no or microinvasion (19 cases); and group 4, group 3 with distinct invasive carcinoma (14 cases). It is suggested that IPN-L progresses from group 1 to group 4. As controls, 20 cases of nonneoplastic intrahepatic large bile ducts and 17 cases of nonpapillary invasive intrahepatic cholangiocarcinoma (ICC) were used. Biliary epithelial hypersecretion of sialomucin rather than sulfomucin was prevalent in IPN-L, and this was associated with the progression of INP-L. Immunohistochemically, cytokeratin (CK) 20 and MUC2, a gastrointestinal marker, were expressed more frequently in IPN-L than in nonneoplastic bile ducts and nonpapillary ICC (P <0.01), and their incidence were significantly increased in parallel with the progression of IPN-L (P < 0.01). In contrast, expression of CK 7, a biliary marker, was decreased in IPN-L compared with nonpapillary ICC. Nuclear p53 immunostaining was detected in 30% of IPN-L as a whole and increased in tandem with the progression of IPN-L (P < 0.01). It is suggested that IPN-L forms a spectrum of biliary epithelial neoplasia with frequent gastrointestinal metaplasia, different from the usual nonpapillary ICC, and shows stepwise progression from the perspective of mucin profile, gastrointestinal metaplasia, and p53 nuclear expression. HUM PATHOL 33:503-511. Copyright 2002, Elsevier Science (USA). All rights reserved.
Aims
The significance of molecular and genetic alterations of p53 and ras in the development and progression as well as the histological differentiation of intrahepatic cholangiocarcinoma (ICC) was ...evaluated.
Methods and results
We examined immunohistochemically ras p21 protein and p53‐related products (p53 protein, WAF‐1 and mdm‐2) in 43 cases of ICC. In addition, point mutations of ras and p53 were examined genetically in selected ICC cases by polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) and direct sequence analysis. Point mutation of K‐ras gene codon 12 was detected in three of 14 cases and one of 15 cases by PCR‐RFLP and direct sequence analysis, respectively. Immunoreactivity of ras p21 protein was not detected. Point mutation of p53 was detected in three of 15 cases. p53 protein was immunohistochemically detectable in 33 of 43 cases. Immunoreactivity of p53 was more frequent in well‐differentiated and less frequent in poorly differentiated cases. Immunoreactivity of WAF‐1 and mdm‐2 was seen in 16 and eight of 43 cases, respectively. Both proteins were frequently detected in the cases positive for p53 protein.
Conclusion
These results suggest that dysregulation of ras is involved in at least 20% of ICC and expression of p53 protein is more significantly involved in ICC, particularly in the well and moderately differentiated cases. While some cases of p53 expression may be explainable by point mutation of p53, there may be some epigenetic phenomena that stabilize p53 protein in ICC. That is, wild type p53 may be stabilized and then detectable by forming complexes with other molecules of p53 downstream effector genes, such as WAF‐1 and mdm‐2.
Spectroscopic studies of extragalactic YSOs have shown a great progress in the last few years. Infrared observations with AKARI made significant contributions to that progress. In this proceeding, we ...are going to introduce our current research on the infrared observations of ices and dust around embedded YSOs in the Magellanic Clouds.
The absorption features due to interstellar ices, especially H2O and CO2 ices, provide us with crucial information on present and past interstellar environments, and thus the evolutionary histories ...of galaxies. Before AKARI, however, few detections of ices were reported for nearby galaxies. The AKARI's unique capability of near-infrared spectroscopy with high sensitivity enables us to systematically study ices in nearby galaxies. Thus we have explored many near-infrared spectra ( 2.5−5μm ) of the 211 pointed observations, searching for the absorption features of ices. As a result, out of 122 nearby galaxies, we have significantly detected H2O ice from 36 galaxies and CO2 ice from 9 galaxies. It is notable that the ices are detected not only in late-type galaxies but also in early-type galaxies. We find that CO2 ice is more compactly distributed near the galactic center than H2O ice. Finally, we suggest that the gas density of a molecular cloud and UV radiation may be important factors to determine the abundance of ices.
Near-infrared (NIR; 2.5–5 μm) low-resolution (λ/Δλ ~ 100) spectra were obtained for a number of Galactic and extragalactic objects with the Infrared Camera (IRC) in the AKARI warm mission. These data ...provide us with the first opportunity to make a systematic study of the 3.3–3.5 μm PAH features in a galactic scale as well as within an object. Whereas the 3.3 μm band is well resolved in most spectra, the 3.5 μm band is not clearly separated from the 3.4 μm band in the IRC spectrum. The intensity ratio of the summation of the 3.4 and 3.5 μm bands to the 3.3 μm band shows a tendency to increase towards the Galactic center, although a large variation in the ratio is also seen in a local scale. A search for deuterated PAH features in the 4 μm region is carried out in IRC NIR spectra. Emission lines originating from the ionized gas together with the detector anomaly hamper an accurate search at certain wavelengths, but little convincing evidence has so far been obtained for the presence of significant features in 4.2–4.7 μm. A conservative upper limit of a few percents is obtained for the integrated intensity ratio of the 4.4–4.7 μm possible features to the 3.3–3.5 μm PAH features in the spectra so far obtained.
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