What's on the horizon for community-based conservation? Emerging threats and opportunities

Community-based conservation can support livelihoods and biodiversity, while reinforcing local and Indigenous values, cultures, and institutions. Its delivery can help address cross-cutting global challenges, such as climate change, conservation, poverty, and food security. Therefore, understanding trends in community-based conservation is pertinent to setting and implementing global goals. We undertook a horizon scan to prioritize 15 emerging threats and opportunities expected to impact the future effectiveness of community-based conservation. Topics relate to global biodiversity policy; human rights; shifting human geography; inclusion, diversity, equity, and access; conservation finance and income; and economic reforms. Our findings offer guidance on strengthening community-based conservation to achieve global environmental and development goals.

Three-dimensional reconstruction of histologic structures in human bone marrow from serial sections of trephine biopsies. Spatial appearance of sinusoidal vessels in primary (idiopathic) osteomyelofibrosis

Computer-based three-dimensional (3D) reconstruction of histologic features permits the assessment of the spatial arrangement of complex structures and has the additional advantage of demonstrating aspects that may be obscured in conventional, two-dimensional evaluations. Until now the spatial appearance of histotopographic details in human bone marrow has not been investigated. In the present study we explored the use of 3D visualization techniques to determine the configuration of sinusoidal vessels and surrounding megakaryocytes in osteomyelofibrosis. Up to 34 serial sections were cut from each trephine biopsy block and stained sequentially by monoclonal antibodies against collagen type IV and megakaryocytes (CD61-Y2/51) to discriminate relevant structures selectively and with high contrast. Images were digitized, and contours were traced manually. A new fast and graphically interactive software package for the reconstruction of 3D objects employing a low-cost personal computer was developed. The system allows reconstructions from any serial image in solid model form using a fast triangulation algorithm. 3D reconstruction emphasizes the close spatial relationship between sinus walls and megakaryocytes in this disorder and exhibits enhanced vascularity with a complex 3D meshwork of branching and tortuous sinusoidal vessels. Furthermore, an increase in luminal distention and aberration from normal shape could be observed. Large and ameboid megakaryocytes were frequently found adjacent to the abluminal surface of the sinus. The method described permits more elaborate insight into the complex topographic relationship of these two morphologic features in human bone marrow and may stimulate applications to other interesting specimens that warrant 3D visualization.

Megakaryocytes and sinus walls in primary osteomyelofibrosis: transendothelial migration as revealed by three-dimensional reconstruction of serial sections following sequential double-immunostaining

Using sequential double-immunostaining and a newly-developed three-dimensional (3D-) reconstruction technique on serially cut sections from bone marrow trephines, we studied the transmural passage of megakaryocytes through the sinus wall. Biopsies derived from patients with primary (idiopathic) osteomyelofibrosis were exposed to monoclonal antibody against type IV collagen to delineate the sinus walls and also the frequently thickened basement membrane. Staining with the primary antibody was followed by Y2/51 (CD61) to identify all elements of megakaryopoiesis. In most instances serial sectioning and 3D-reconstruction revealed an amoeboid shape of megakaryocytes and a tandem-like arrangement in close spatial contact with the abluminal surface of the sinus wall. Preceded by formation of cytoplasmic processes, straight penetration of entire megakaryocytes through gaps in the sinus walls into the lumen was seen. Where collagen deposits apparently presented a barrier, a mole-like tunnelling through the basement membrane material (type IV collagen) was recognizable. Our findings are in keeping with the assumption that megakaryocyte locomotion is an essential requirement for normal thrombocytogenesis.