Single-cell heterogeneity in ductal carcinoma in situ of breast.

Heterogeneous patterns of mutations and RNA expression have been well documented in invasive cancers. However, technological challenges have limited the ability to study heterogeneity of protein expression. This is particularly true for pre-invasive lesions such as ductal carcinoma in situ of the breast. Cell-level heterogeneity in ductal carcinoma in situ was analyzed in a single 5 µm tissue section using a multiplexed immunofluorescence analysis of 11 disease-related markers (EGFR, HER2, HER4, S6, pmTOR, CD44v6, SLC7A5 and CD10, CD4, CD8 and CD20, plus pan-cytokeratin, pan-cadherin, DAPI, and Na+K+ATPase for cell segmentation). Expression was quantified at cell level using a single-cell segmentation algorithm. K-means clustering was used to determine co-expression patterns of epithelial cell markers and immune markers. We document for the first time the presence of epithelial cell heterogeneity within ducts, between ducts and between patients with ductal carcinoma in situ. There was moderate heterogeneity in a distribution of eight clusters within each duct (average Shannon index 0.76; range 0-1.61). Furthermore, within each patient, the average Shannon index across all ducts ranged from 0.33 to 1.02 (s.d. 0.09-0.38). As the distribution of clusters within ducts was uneven, the analysis of eight ducts might be sufficient to represent all the clusters ie within- and between-duct heterogeneity. The pattern of epithelial cell clustering was associated with the presence and type of immune infiltrates, indicating a complex interaction between the epithelial tumor and immune system for each patient. This analysis also provides the first evidence that simultaneous analysis of both the epithelial and immune/stromal components might be necessary to understand the complex milieu in ductal carcinoma in situ lesions.

Platelet activation using electric pulse stimulation: growth factor profile and clinical implications.

BACKGROUND: Autologous platelet gel therapy using platelet-rich plasma has emerged as a promising alternative for chronic wound healing, hemostasis, and wound infection control. A critical step for this therapeutic approach is platelet activation, typically performed using bovine thrombin (BT) and calcium chloride. However, exposure of humans to BT can stimulate antibody formation, potentially resulting in severe hemorrhagic or thrombotic complications. Electric pulse stimulation using nanosecond PEFs (pulse electric fields) is an alternative, nonbiochemical platelet activation method, thereby avoiding exposure to xenogeneic thrombin and associated risks. METHODS: In this study, we identified specific requirements for a clinically relevant activator instrument by dynamically measuring current, voltage, and electric impedance for platelet-rich plasma samples. From these samples, we investigated the profile of growth factors released from human platelets with electric pulse stimulation versus BT, specifically platelet-derived growth factor, transforming growth factor ß, and epidermal growth factor, using commercial enzyme-linked immunosorbent assay kits. RESULTS: Electric pulse stimulation triggers growth factor release from platelet α-granules at the same or higher level compared with BT. CONCLUSION: Electric pulse stimulation is a fast, inexpensive, easy-to-use platelet activation method for autologous platelet gel therapy.

Identification of the protein target of myelin-binding ligands by immunohistochemistry and biochemical analyses.

The ability to visualize myelin is important in the diagnosis of demyelinating disorders and the detection of myelin-containing nerves during surgery. The development of myelin-selective imaging agents requires that a defined target for these agents be identified and that a robust assay against the target be developed to allow for assessment of structure-activity relationships. We describe an immunohistochemical analysis and a fluorescence polarization binding assay using purified myelin basic protein (MBP) that provides quantitative evidence that MBP is the molecular binding partner of previously described myelin-selective fluorescent dyes such as BMB, GE3082, and GE3111.

Intraoperative fluorescence imaging of peripheral and central nerves through a myelin-selective contrast agent.

PURPOSE: Patients suffer from complications as a result of unintentional nerve damage during surgery. We focus on improving intraoperative visualization of nerves through the use of a targeted fluorophore and optical imaging instrumentation. PROCEDURE: A myelin-targeting fluorophore, GE3111, was synthesized, characterized for its optical and myelin-binding properties using purified myelin basic protein, and evaluated in mice. Additionally, a compact instrument was adapted to visualize nerves. RESULTS: GE3111 was synthesized using a versatile methodology. Its optical properties were sensitive to the local environment both in vitro and in vivo. Following intravenous injection, central and peripheral nerves were visualized, with the kinetics of nerve uptake modifiable depending on the formulation. Fluorescence polarization showed specific and strong binding to purified myelin basic protein. Nerves were visualized in vivo using a dedicated compact imaging device requiring less than 2.5 mW/cm(2) of illumination at 405 nm. CONCLUSIONS: Fluorescence imaging of nerves through myelin showed a potential for use in image-guided surgery. Intraoperative nerve imaging is an example where contrast agent and instrument development come together as a result of clinical need.