Size distribution of Antarctic micrometeorites stored in surface snow near Dome Fuji Station

The Tenth Symposium on Polar Science/Special session: [OA] Antarctic meteorites, Thur. 5 Dec. / 3F Multipurpose conference room, National Institute of Polar Researc

Petrologic subtypes of CM chondrites: Reinvestigation and proposal of subtypes 3.0 to 2.8

The Tenth Symposium on Polar Science/Poster presentations: [OA] Antarctic meteorites, Wed. 4 Dec. / Entrance Hall (1st floor), National Institute of Polar Researc

Immunosuppression for islet transplantation.

The development by the Edmonton group of a sirolimus-based, steroid-free, low-tacrolimus regimen is a significant breakthrough that allows the rate of insulin independence after islet transplantation to increase from 13% to 80% at 1 year ; however, the rate is reduced to 50% at 3 years, attributed to prolonged tacrolimus exposure. Recently, immunosuppression agents such as cyclosporine, mycophenolate mofetil, and the novel agent FTY 720 have been used instead of tacrolimus. Lymphocytedepleting antibodies such as anti-thymocyte globulin, alemtuzumab, and hOKT3gamma 1 (ala, ala) have been launched, and a costimulatory blockade of anti-CD40 monoclonal antibodies and CTLA4-Ig will be attempted in the near future. Moreover, the potential of a novel immunosuppressing peptide could now be realized using new technology called the protein transduction system. In this review, we show some of the most recent contributions to the advancement of knowledge in this field

Induction of Expandable Tissue-Specific Progenitor Cells from Human Pancreatic Tissue through Transient Expression of Defined Factors

We recently demonstrated the generation of mouse induced tissue-specific stem (iTS) cells through transient overexpression of reprogramming factors combined with tissue-specific selection. Here we induced expandable tissue-specific progenitor (iTP) cells from human pancreatic tissue through transient expression of genes encoding the reprogramming factors OCT4 (octamer-binding transcription factor 4), p53 small hairpin RNA (shRNA), SOX2 (sex-determining region Y-box 2), KLF4 (Kruppel-like factor 4), L-MYC, and LIN28. Transfection of episomal plasmid vectors into human pancreatic tissue efficiently generated iTP cells expressing genetic markers of endoderm and pancreatic progenitors. The iTP cells differentiated into insulin-producing cells more efficiently than human induced pluripotent stem cells (iPSCs). iTP cells continued to proliferate faster than pancreatic tissue cells until days 100–120 (passages 15–20). iTP cells subcutaneously inoculated into immunodeficient mice did not form teratomas. Genomic bisulfite nucleotide sequence analysis demonstrated that the OCT4 and NANOG promoters remained partially methylated in iTP cells. We compared the global gene expression profiles of iPSCs, iTP cells, and pancreatic cells (islets >80%). Microarray analyses revealed that the gene expression profiles of iTP cells were similar, but not identical, to those of iPSCs but different from those of pancreatic cells. The generation of human iTP cells may have important implications for the clinical application of stem/progenitor cells

Nodal Merkel Cell Carcinoma in Head and Neck Lesions with an Unknown Primary: A Case Report in Light of the Literature

Merkel cell carcinoma (MCC) is a rare but aggressive neuroendocrine skin cancer. To diagnose nodal MCC with an unknown primary disease is challenging, and it has to be separated from other nodal metastatic neoplasms. We report a unique case of nodal MCC in head and neck lesions with an unknown primary. A 70-year-old woman was admitted to our department with a right submandibular mass. Fine needle aspiration biopsy was performed and indicated malignancy. F-18-fluorodeoxyglucose positron emission tomography (PET) demonstrated abnormal accumulation in the right submandibular lymph node, right palatine tonsil, and right thyroid gland. For diagnostics and treatment, bilateral selective neck lymph node dissection, right tonsillectomy, and right thyroidectomy were performed. Histopathological examination revealed that most parts of the submandibular lymph node were occupied by diffuse sheets of tumor cells. Contrary to our expectation, malignant cells were not detected in the right palatine tonsil and right thyroid. Immunohistochemistry demonstrated a marked positive reaction for AE1/AE3, chromogranin A, synaptophysin, cytokeratin 20 (CK20) and CD56 and a negative reaction for vimentin, leucocyte common antigen (LCA), thyroid transcription factor-1 (TTF1) and cytokeratin 7 (CK7) in the tumor cells. Immunostaining of Merkel cell polyomavirus-large T antigen (MCPyV-LT) showed a positive reaction and MCPyV-positive MCCs were assessed by PCR analysis, demonstrating that viral copy number was 12.8 copies per cell. These histological findings confirmed the diagnosis of Merkel cell carcinoma of the lymph node. In cases of tumors in the lymph node with a neuroendocrine appearance in head and neck lesions, it is necessary to eliminate the possibility of metastasis from MCC

A consortium study of Antarctic micrometeorites recovered from the Dome Fuji Station

Deposits in the water tank at the Dome Fuji Station were collected by the 37th Japanese Antarctic Research Expedition team in 1996. We recovered 233 micrometeorites from the deposits. A consortium study was started in late 1998 to investigate mineralogy, petrology, bulk chemistry, and isotopic compositions of the micrometeorites. This is the first case of an organized study of micrometeorites in Japan, in order to establish the methods to investigate micrometeorites routinely. Consortium results on mineralogy, petrology, minor and trace element compositions, isotopic compositions of noble gases of the micrometeorites are reported in this volume. We also found a sequence of mineralogical and compositional changes of micrometeorites experienced from frictional heating during atmospheric entry. INAA and ion probe studies are now in progress

Cyclin D1 activation through ATF-2 in Reg-induced pancreatic β-cell regeneration

AbstractRegenerating gene product (Reg) is induced in pancreatic β-cells and acts as an autocrine/paracrine growth factor for regeneration via a cell surface Reg receptor. However, the manner by which Reg induces β-cell regeneration was unknown. In the present study, we found that Reg increased phospho-ATF-2, which binds to −57 to −52 of the cyclin D1 gene to activate the promoter. The Reg/ATF-2-induced cyclin D1 promoter activation was attenuated by PI(3)K inhibitors such as LY294002 and wortmannin. In Reg knockout mouse islets, the levels of phospho-ATF-2, cyclin D1, and phospho-Rb were greatly decreased. These results indicate that the Reg–Reg receptor system stimulates the PI(3)K/ATF-2/cyclin D1 signaling pathway to induce β-cell regeneration

Antarctic micrometeorites collected at the Dome Fuji Station

Antarctic micrometeorites (AMMs) were found among the precipitated fine particles recovered from a water tank in the Dome Fuji Station. These AMMs had been contained in the recent fallen snow around the station. Initial processing of the precipitated particles revealed that they were dominated by natural and artificial terrestrial materials, thus a series of processes were developed to separate AMMs from terrestrial particles. The recovery rate of AMMs by the processes was approximately 45% in weight, which was determined from a weight ratio of recovered/accreted AMMs. The micro-morphology and major-element concentration of the recovered AMMs were characterized. They appear to have been heated upon atmospheric entry to varying temperatures and can be classified into two major types based on the degree of heating : (1) fine-grained, irregular-shaped, partial-melted micrometeorites with chondritic composition, and (2) total-melted spherical micrometeorites with chondritic composition except for volatile elements. A digital catalog for the AMMs identified in this study was established on the web site [URL : http : //dust. cc. gakushuin. ac. jp/], in which optical characteristics, high-resolution images, and chemical compositions of individual AMMs are presented. The AMMs listed in the catalog are the first Japanese collection of extraterrestrial dust. The criterion and techniques developed for the selection and initial analysis of AMMs are applicable for the dust samples that are being collected by the 39th Japanese Antarctic Research Expedition team

Metastatic Renal Cell Carcinoma to the Left Sphenoid Sinus: A Case Report in Light of the Literature

A 79-year-old Japanese woman presented with a rare case of metastatic renal cell carcinoma to the left sphenoid sinus with left nasal bleeding. She had previously had right radical nephrectomy for renal cell carcinoma at the age of 64 years and brain and spinal cord infarction at 74 years. Endoscopic examination revealed no mass in the nasal cavity. CT and MRI revealed a tumor in the left sphenoid sinus. The size of the tumor increased gradually from 12 to 15 years after the radical nephrectomy. Complete resection with endoscopic surgery was performed without preoperative embolization. The tumor cells had clear cytoplasm and were arranged in a trabecular pattern lined by a layer of endothelial cells. These findings were identical to the pathological findings of the surgical specimen of the renal cell carcinoma from 15 years previous. A pathological diagnosis of metastatic renal cell carcinoma of clear cell type (grade 1) was made. PET-CT demonstrated no metastasis. The patient’s condition was successfully managed with excision of the tumor, and she remains well with no evidence of recurrence and metastasis 36 months after treatment. Metastatic renal cell carcinoma to the sphenoid sinus is rare, but it might be considered in the differential diagnosis of masses in the paranasal sinus even long after initial treatment of renal cancer

Formation of an Ultracarbonaceous Antarctic Micrometeorite through Minimum Aqueous Alteration in a Small Porous Icy Body

A comprehensive study of the organic chemistry and mineralogy of an ultracarbonaceous micrometeorite (UCAMM D05IB80) collected from near the Dome Fuji Station, Antarctica, was carried out to understand the genetic relationship among organic materials, silicates, and water. The micrometeorite is composed of a dense aggregate of ∼5 µm-sized hollow ellipsoidal organic material containing submicrometer-sized phases such as glass with embedded metal and sulfides (GEMS) and mineral grains. There is a wide area of organic material (∼15 × 15 μm) in its interior. Low-Ca pyroxene is much more abundant than olivine and shows various Mg/(Mg + Fe) ratios ranging from ∼1.0 to 0.78, which is common to previous works on UCAMMs. By contrast, GEMS grains in this UCAMM have unusual chemical compositions. They are depleted in both Mg and S, which suggests that these elements were leached out from the GEMS grains during very weak aqueous alteration, without the formation of phyllosilicates. The organic materials have two textures—smooth and globular with an irregular outline—and these are composed of imine, nitrile and/or aromatic nitrogen heterocycles, and amide. The ratio of nitrogen to carbon (N/C) in the smooth region of the organics is ∼0.15, which is five times higher than that of insoluble organic macromolecules in types 1 and 2 carbonaceous chondritic meteorites. In addition, the UCAMM organic materials are soluble in epoxy and are thus hydrophilic; this polar nature indicates that they are very primitive. The surface of the material is coated with an inorganic layer, a few nanometers thick, that consists of C, O, Si, S, and Fe. Sulfur is also contained in the interior, implying the presence of organosulfur moieties. There are no isotopic anomalies of D, 13C, or 15N in the organic material. Interstellar photochemistry alone would not be sufficient to explain the N/C ratio of the UCAMM organics; therefore, we suggest that a very small amount of fluid on a comet must have been necessary for the formation of the UCAMM. The GEMS grains depleted in Mg and S in the UCAMM prove a very weak degree of aqueous alteration; weaker than that of carbonaceous chondrites. Short-duration weak alteration probably caused by planetesimal shock locally melted cometary ice grains and released water that dissolved the organics; the fluid would likely have not mobilized because of the very low thermal conductivity of the porous icy body. This event allowed the formation of the large organic puddle of the UCAMM, as well as organic matter sulfurization, formation of thin membrane-like layers of minerals, and deformation of organic nanoglobules.アクセプト後にタイトル・アブストラクト等変更あり、著者最終稿は変更前のタイトル"Formation of an Ultracarbonaceous Antarctic Micrometeorite through Minimum Aqueous Alteration in a Small Porous Icy Body"This work was supported by a Grant-in-Aid for Scientific Research from the Japanese Ministry of Education, Culture, Sports, Science and Technology (No. 22224010, PI: H. Nagahara). The STXM facility at the beamline 5.3.2.2, ALS, is supported by the Department of Energy, Basic Energy Sciences Program