Rosette formation in white blood cell cultures from patients with acute myeloblastic leukemia

Zusammenfassung In Monozyten enthaltenden Leukozyten-Kulturen von Patienten mit akuter myeloischer Leukämie entstehen nach ungefähr 8 h Inkubationszeit Rosetten, die aus einem von Myeloblasten umgebenen Monozyten bestehen. In Analogie zu anderen in vitro-Systemen, in welchen sich eine Rosettenbildung beobachten lässt, könnte diese zelluläre Reaktion auf dem Vorhandensein von spezifischen Antikörpern im Patienten-Serum beruhen, welche gegen die leukämischen Myeloblasten gerichtet sind.     

Verbesserte Methode zur Gewinnung und Verarbeitung von freien Zellen aus kleinsten Volumina von Körperflüssigkeiten mittels Membranfiltration

Summary A cell collector for concentrating small numbers of exfoliated cells on membrane filters from minute volumes (0.05–3 ml) of body fluids and culture media is described. The apparatus incorporates a membrane pump, delivering a vacuum of 10–100 mm Hg. Filtration units (funnels and filter holders) with filtrating areas of 3, 5 and 8 mm diameter are used depending on the volume and the cell content of the fluid to be investigated. A rapid staining procedure based on the classical May-Grünwald-Giemsa technique for light microscopic observations and a modified technique for processing the cell-coated filters for electron microscopy are presented in some detail.

---

---

Mit Unterstützung durch den Schweizerischen Nationalfonds zur Förderung der wissenschaftlichen Forschung.     

Interactions between cancer stem cells and their niche govern metastatic colonization

Metastatic growth in distant organs is the major cause of cancer mortality. The development of metastasis is a multistage process with several rate-limiting steps. Although dissemination of tumour cells seems to be an early and frequent event, the successful initiation of metastatic growth, a process termed 'metastatic colonization', is inefficient for many cancer types and is accomplished only by a minority of cancer cells that reach distant sites. Prevalent target sites are characteristic of many tumour entities, suggesting that inadequate support by distant tissues contributes to the inefficiency of the metastatic process. Here we show that a small population of cancer stem cells is critical for metastatic colonization, that is, the initial expansion of cancer cells at the secondary site, and that stromal niche signals are crucial to this expansion process. We find that periostin (POSTN), a component of the extracellular matrix, is expressed by fibroblasts in the normal tissue and in the stroma of the primary tumour. Infiltrating tumour cells need to induce stromal POSTN expression in the secondary target organ (in this case lung) to initiate colonization. POSTN is required to allow cancer stem cell maintenance, and blocking its function prevents metastasis. POSTN recruits Wnt ligands and thereby increases Wnt signalling in cancer stem cells. We suggest that the education of stromal cells by infiltrating tumour cells is an important step in metastatic colonization and that preventing de novo niche formation may be a novel strategy for the treatment of metastatic disease.     

Cutaneous cancer stem cell maintenance is dependent on beta-catenin signalling

Continuous turnover of epithelia is ensured by the extensive self-renewal capacity of tissue-specific stem cells. Similarly, epithelial tumour maintenance relies on cancer stem cells (CSCs), which co-opt stem cell properties. For most tumours, the cellular origin of these CSCs and regulatory pathways essential for sustaining stemness have not been identified. In murine skin, follicular morphogenesis is driven by bulge stem cells that specifically express CD34. Here we identify a population of cells in early epidermal tumours characterized by phenotypic and functional similarities to normal bulge skin stem cells. This population contains CSCs, which are the only cells with tumour initiation properties. Transplants derived from these CSCs preserve the hierarchical organization of the primary tumour. We describe beta-catenin signalling as being essential in sustaining the CSC phenotype. Ablation of the beta-catenin gene results in the loss of CSCs and complete tumour regression. In addition, we provide evidence for the involvement of increased beta-catenin signalling in malignant human squamous cell carcinomas. Because Wnt/beta-catenin signalling is not essential for normal epidermal homeostasis, such a mechanistic difference may thus be targeted to eliminate CSCs and consequently eradicate squamous cell carcinomas.     

人类的太空未来

人类像乘飞机那样方便地乘太空交通工具巡游外层空间在近几十年的未来可能还实现不了,但在此期间我们将孜孜不倦地为达此目的而攻研多项重大课题：倾全力设计新型发射运载工具、建立国际太空空间站、寻索太空能……l993年,美国国会通过一项表决,拯救了国际太空空间站项目的立项,这是发生在人类征服太空史上的一件重大事件,此项意义特殊重大的关键可能将要深深影响着人类的未来。事实已经证明,建造国际太空空间站实际上对西方国家探索日益增长的大量科技领域新知提供了促激动力。若人类不希望成为仅立足于地球上而面临人口日益拥挤的被…     

The cyclic nucleotide-gated ion channel CNGA3 contributes to coolness-induced responses of Grueneberg ganglion neurons

Localized to the vestibule of the nasal cavity, neurons of the Grueneberg ganglion (GG) respond to cool ambient temperatures. The molecular mechanisms underlying this thermal response are still elusive. Recently, it has been suggested that cool temperatures may activate a cyclic guanosine monophosphate (cGMP) pathway in the GG, which would be reminiscent of thermosensory neurons in Caenorhabditis elegans. In search for other elements of such a cascade, we have found that the cyclic nucleotide-gated ion channel CNGA3 was strongly expressed in the GG and that expression of CNGA3 was confined to those cells that are responsive to coolness. Further experiments revealed that the response of GG neurons to cool temperatures was significantly reduced in CNGA3-deficient mice compared to wild-type conspecifics. The observation that a cGMP-activated non-selective cation channel significantly contributes to the coolness-evoked response in GG neurons strongly suggests that a cGMP cascade is part of the transduction process.     

Haemangioblast commitment is initiated in the primitive streak of the mouse embryo

Haematopoietic and vascular cells are thought to arise from a common progenitor called the haemangioblast. Support for this concept has been provided by embryonic stem (ES) cell differentiation studies that identified the blast colony-forming cell (BL-CFC), a progenitor with both haematopoietic and vascular potential. Using conditions that support the growth of BL-CFCs, we identify comparable progenitors that can form blast cell colonies (displaying haematopoietic and vascular potential) in gastrulating mouse embryos. Cell mixing and limiting dilution analyses provide evidence that these colonies are clonal, indicating that they develop from a progenitor with haemangioblast potential. Embryo-derived haemangioblasts are first detected at the mid-streak stage of gastrulation and peak in number during the neural plate stage. Analysis of embryos carrying complementary DNA of the green fluorescent protein targeted to the brachyury locus demonstrates that the haemangioblast is a subpopulation of mesoderm that co-expresses brachyury (also known as T) and Flk-1 (also known as Kdr). Detailed mapping studies reveal that haemangioblasts are found at highest frequency in the posterior region of the primitive streak, indicating that initial stages of haematopoietic and vascular commitment occur before blood island development in the yolk sac.     

Optimizing the Irrigation Scheduling Strategy and the Water Use Efficiency in Steppe and Irrigated Crop Production Ecosystems in the Northwestern China

ＩｎｔｒｏｄｕｃｔｉｏｎＳｉｎｃｅｔｈｅｌａｔｅ 1970ｓａｌａｒｇｅｎｕｍｂｅｒｏｆｓｔｕｄｉｅｓｈａｖｅｃｏｎｓｉｄｅｒｅｄｉｒｒｉｇａｔｉｏｎｓｃｈｅｄｕｌｉｎｇｉｎｉｒｒｉｇａｔｉｏｎｍａｎａｇｅｍｅｎｔ[1- 7] ａｎｄｉｔｈａｓｂｅｅｎｓｈｏｗｎｔｈａｔｅｆｆｉｃｉｅｎｔａｎｄ ｐｒｏｆｉｔａｂｌｅｉｒｒｉｇａｔｉｏｎｓｃｈｅｄｕｌｉｎｇｓｔｒａｔｅｇｉｅｓａｒｅｎｅｅｄｅｄ ,ｐａｒｔｉｃｕｌａｒｌｙｗｈｅｒｅｗａｔｅｒａｖａｉｌａｂｌｅｆｏｒｉｒｒｉｇａｔｉｏｎｉｓｌｉｍｉｔｅｄ .Ｉｎｎｏ…