Publications by authors named "Helena Chmelova"

Article Synopsis
  • Super-resolution microscopy provides high-detail imaging but faces challenges with thick biological specimens, such as oocytes.
  • Optimizing sample preparation is crucial for achieving optical clarity, which enhances imaging capabilities for larger structures.
  • This study introduces a new method involving alcohol dehydration and high-refractive-index mounting, allowing for successful 3D imaging of mouse oocytes, thereby improving the analysis of complex biological processes.
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Cephalochordates (amphioxi or lancelets) are representatives of the most basally divergent group of the chordate phylum. Studies of amphioxus development and anatomy hence provide a key insight into vertebrate evolution. More widespread use of amphioxus in the evo-devo field would be greatly facilitated by expanding the methodological toolbox available in this model system.

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Islet-cell hormone release is modulated by signals from endothelial and endocrine cells within the islet. However, models of intraislet vascularization and paracrine cell signaling are mostly based on the rodent pancreas. We assessed the architecture and endocrine cell interaction of the vascular network in unperturbed human islets in situ and their potential to re-establish their endogenous vascular network after transplantation in vivo.

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Insulin-dependent diabetes is a complex multifactorial disorder characterized by loss or dysfunction of β-cells. Pancreatic β-cells differ in size, glucose responsiveness, insulin secretion and precursor cell potential; understanding the mechanisms that underlie this functional heterogeneity might make it possible to develop new regenerative approaches. Here we show that Fltp (also known as Flattop and Cfap126), a Wnt/planar cell polarity (PCP) effector and reporter gene acts as a marker gene that subdivides endocrine cells into two subpopulations and distinguishes proliferation-competent from mature β-cells with distinct molecular, physiological and ultrastructural features.

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Emerging insulin resistance is normally compensated by increased insulin production of pancreatic β-cells, thereby maintaining normoglycemia. However, it is unclear whether this is achieved by adaptation of β-cell function, mass, or both. Most importantly, it is still unknown which of these adaptive mechanisms fail when type 2 diabetes develops.

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Cure of type 1 diabetes (T1D) by immune intervention at disease onset depends on the restoration of insulin secretion by endogenous β-cells. However, little is known about the potential of β-cell mass and function to recover after autoimmune attack ablation. Using a longitudinal in vivo imaging approach, we show how functional status and mass of β-cells adapt in response to the onset and remission of T1D.

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IL-2/anti-IL-2 mAb immunocomplexes were described to have dramatically higher activity than free IL-2 in vivo. We designed protein chimera consisting of IL-2 linked to light chain of anti-IL-2 mAb S4B6 through flexible oligopeptide spacer (Gly(4)Ser)(3). This protein chimera mimics the structure of IL-2/S4B6 mAb immunocomplexes but eliminates general disadvantages of immunocomplexes like possible excess of either IL-2 or anti-IL-2 mAb and their dissociation to antibody and IL-2 at low concentrations.

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Interleukin (IL)-2 has been approved for treatment of metastatic renal cancer and malignant melanoma. However, its unfavorable pharmacologic properties, severe side effects and the negative role of IL-2 in maintaining T regulatory cells are severe drawbacks. It has been shown that immunocomplexes of IL-2 and certain anti-IL-2 mAbs possess selective and high stimulatory activity in vivo.

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IL-2 is potent imunostimulatory molecule that plays a key role in T and NK cell activation and expansion. IL-2 is approved by the FDA to treat metastatic renal cancer and melanoma, but its extremely short half-life and serious toxicities are significant limitations of its use. It was reported that in vivo biological activity of IL-2 can be increased by association of IL-2 with anti-IL-2 mAb (S4B6).

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BALB/c mice bearing syngeneic BCL1 leukemia, a mouse model of human chronic lymphocytic leukemia, were treated with polymer-bound doxorubicin conjugate targeted with BCL1-specific monoclonal antibody. Such treatment can cure up to 100% of mice and the cured mice show long-lasting resistance to BCL1 leukemia. We show that both CD4+ and CD8+ T cells are required for establishment of the resistance, but only CD8+ T cells are necessary for its maintenance.

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