420 research outputs found

    Coupling of electron rotation with spin in semiconductors

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    Account of an intrinsic spin-orbit coupling in the valence bands of common semiconductors yields the scalar spin-orbit-rotation term in the effective-mass Hamiltonian of the conduction-band electron. This result is obtained within the multiband envelope function approximation. Fundamentally, the spin-orbit-rotation coupling can be described in purely geometric terms as a consequence of the difference in the Berry phase acquired by the components of the spin-orbitally mixed Kramers-doublet during its cyclic evolution in the reciprocal momentum space.Comment: Will appear in Phys. Lett.

    A case of placenta previa accreta successfully treated by open infrarenal aortic clamping

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    Open infrarenal aortic clamping has been performed for traumatic pelvic hemorrhage or aortic rupture, and there are few reports of its use in the field of obstetrics and gynecology1). We report a patient with placenta previa accreta who was successfully treated by open infrarenal aortic clamping

    Depletion of Lipid Efflux Pump ABCG1 Triggers the Intracellular Accumulation of Extracellular Vesicles and Reduces Aggregation and Tumorigenesis of Metastatic Cancer Cells

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    The ATP-binding cassette transporter G1 (ABCG1) is a cholesterol lipid efflux pump whose role in tumor growth has been largely unknown. Our transcriptomics revealed that ABCG1 was powerfully expressed in rapidly metastatic, aggregative colon cancer cells, in all the ABC transporter family members. Coincidently, genetic amplification of ABCG1 is found in 10–35% of clinical samples of metastatic cancer cases. Expression of ABCG1 was further elevated in three-dimensional tumoroids (tumor organoids) within stemness-enhancing tumor milieu, whereas depletion of ABCG1 lowered cellular aggregation and tumoroid growth in vitro as well as hypoxia-inducible factor 1Ξ± in cancer cells around the central necrotic areas in tumors in vivo. Notably, depletion of ABCG1 triggered the intracellular accumulation of extracellular vesicles (EVs) and regression of tumoroids. Collectively, these data suggest that ABCG1 plays a crucial role in tumorigenesis in metastatic cancer and that depletion of ABCG1 triggers tumor regression with the accumulation of EVs and their derivatives and cargos, implicating a novel ABCG1-targeting therapeutic strategy by which redundant and toxic substances may be accumulated in tumors leading to their regression

    AMH producing purely cystic virilizing adult granulosa cell tumor in 17Β years old girl: a case report and review of literatures

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    Background: Androgen-producing granulosa cell tumor in adolescent girl is rare condition and clinical characteristics are not fully elucidated. Case presentation: Seventeen years old girl complained of secondary amenorrhea was referred to our out-patient consultation. Markedly elevated serum testosterone, LH, and AMH levels were noted. Mild hirsutism and clitoromegaly were presented. Transabdominal ultrasonography and MRI revealed cystic mass occupied pelvic cavity probably originated from left ovary. Right ovary showed polycystic appearance. Laparoscopic left ovarian cystectomy was performed. After the surgery, her menstruation resumed along with normalized hormonal parameters, and clinical hyperandrogenism were improved. Since the scarcity of cellular lining of inner cyst wall, definitive pathological diagnosis was difficult. After the consultation with gynecological pathologist, the tumor was diagnosed as sex cord stromal tumor, highly suspicious for adult granulosa cell tumor. Residual left salpingo-oophorectomy was performed by additional laparoscopic surgery. Her serum testosterone and AMH levels were remained low with regular menstrual cycles and no evidence of recurrence. Conclusions: Androgen-producing cystic granulosa cell tumor is rare gynecological disorders, which need both gynecologic oncological and endocrinological approach. Its clinical manifestations may bring some clues to the pathogenesis of ovulatory dysfunctions, such as polycystic ovary syndrome

    Organoids with cancer stem cell-like properties secrete exosomes and HSP90 in a 3D nanoenvironment

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    Ability to form cellular aggregations such as tumorspheres and spheroids have been used as a morphological marker of malignant cancer cells and in particular cancer stem cells (CSC). However, the common definition of the types of cellular aggregation formed by cancer cells has not been available. We examined morphologies of 67 cell lines cultured on three dimensional morphology enhancing NanoCulture Plates (NCP) and classified the types of cellular aggregates that form. Among the 67 cell lines, 49 cell lines formed spheres or spheroids, 8 cell lines formed grape-like aggregation (GLA), 8 cell lines formed other types of aggregation, and 3 cell lines formed monolayer sheets. Seven GLA-forming cell lines were derived from adenocarcinoma among the 8 lines. A neuroendocrine adenocarcinoma cell line PC-3 formed asymmetric GLA with ductal structures on the NCPs and rapidly growing asymmetric tumors that metastasized to lymph nodes in immunocompromised mice. In contrast, another adenocarcinoma cell line DU-145 formed spheroids in vitro and spheroid-like tumors in vivo that did not metastasize to lymph nodes until day 50 after transplantation. Culture in the 3D nanoenvironment and in a defined stem cell medium enabled the neuroendocrine adenocarcinoma cells to form slowly growing large organoids that expressed multiple stem cell markers, neuroendocrine markers, intercellular adhesion molecules, and oncogenes in vitro. In contrast, the more commonly used 2D serum-contained environment reduced intercellular adhesion and induced mesenchymal transition and promoted rapid growth of the cells. In addition, the 3D stemness nanoenvironment promoted secretion of HSP90 and EpCAM-exosomes, a marker of CSC phenotype, from the neuroendocrine organoids. These findings indicate that the NCP-based 3D environment enables cells to form stem cell tumoroids with multipotency and model more accurately the in vivo tumor status at the levels of morphology and gene expression
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