The Experts below are selected from a list of 834 Experts worldwide ranked by ideXlab platform
Stefan W Hell - One of the best experts on this subject based on the ideXlab platform.
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fluorescence nAnoscopy in cell biology
Nature Reviews Molecular Cell Biology, 2017Co-Authors: Steffen J Sahl, Stefan Jakobs, Stefan W HellAbstract:Fluorescence nAnoscopy enables the optical imaging of cellular components with resolutions at the nanometre scale. With the growing availability of super-resolution microscopes, nAnoscopy methods are being increasingly applied. Quantitative, multicolour, live-cell nAnoscopy and the corresponding labelling strategies are under continuous development.
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fluorescence nAnoscopy in cell biology
Nature Reviews Molecular Cell Biology, 2017Co-Authors: Steffen J Sahl, Stefan Jakobs, Stefan W HellAbstract:Fluorescence nAnoscopy uniquely combines minimally invasive optical access to the internal nanoscale structure and dynamics of cells and tissues with molecular detection specificity. While the basic physical principles of 'super-resolution' imaging were discovered in the 1990s, with initial experimental demonstrations following in 2000, the broad application of super-resolution imaging to address cell-biological questions has only more recently emerged. NAnoscopy approaches have begun to facilitate discoveries in cell biology and to add new knowledge. One current direction for method improvement is the ambition to quantitatively account for each molecule under investigation and assess true molecular colocalization patterns via multi-colour analyses. In pursuing this goal, the labelling of individual molecules to enable their visualization has emerged as a central challenge. Extending nanoscale imaging into (sliced) tissue and whole-animal contexts is a further goal. In this Review we describe the successes to date and discuss current obstacles and possibilities for further development.
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cell permeant large stokes shift dyes for transfection free multicolor nAnoscopy
Journal of the American Chemical Society, 2017Co-Authors: Alexey N Butkevich, Gražvydas Lukinavicius, Elisa Deste, Stefan W HellAbstract:We designed cell-permeant red-emitting fluorescent dye labels with >140 nm Stokes shifts based on 9-iminoanthrone, 9-imino-10-silaxanthone, and 9-imino-10-germaxanthone fluorophores. The corresponding probes selectively targeting mitochondria, lysosomes, and F-actin demonstrate low toxicity and enable stimulated emission depletion (STED) nAnoscopy in neurons, human fibroblasts, U2OS, and HeLa cells. In combination with known small Stokes shift dyes, our probes allow live-cell three-color STED nAnoscopy of endogenous targets on popular setups with 775 nm STED wavelength.
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Cell-Permeant Large Stokes Shift Dyes for Transfection-Free Multicolor NAnoscopy
2017Co-Authors: Alexey N Butkevich, Gražvydas Lukinavičius, Elisa D’este, Stefan W HellAbstract:We designed cell-permeant red-emitting fluorescent dye labels with >140 nm Stokes shifts based on 9-iminoanthrone, 9-imino-10-silaxanthone, and 9-imino-10-germaxanthone fluorophores. The corresponding probes selectively targeting mitochondria, lysosomes, and F-actin demonstrate low toxicity and enable stimulated emission depletion (STED) nAnoscopy in neurons, human fibroblasts, U2OS, and HeLa cells. In combination with known small Stokes shift dyes, our probes allow live-cell three-color STED nAnoscopy of endogenous targets on popular setups with 775 nm STED wavelength
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sted nAnoscopy combined with optical tweezers reveals protein dynamics on densely covered dna
Nature Methods, 2013Co-Authors: Iddo Heller, Stefan W Hell, Gerrit Sitters, Onno D Broekmans, Geraldine Farge, Carolin Menges, Wolfgang Wende, Erwin J G Peterman, Gijs J L WuiteAbstract:Single DNA-binding proteins can be tracked on densely covered DNA at high spatial and temporal resolution and in the presence of high protein concentrations by using a technique that combines optical tweezers, confocal fluorescence microscopy and stimulated emission depletion (STED) nAnoscopy.
Elizabeth A Stier - One of the best experts on this subject based on the ideXlab platform.
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cervical and anal hpv infection and dysplasia in hiv infected women
Infectious Agents and Cancer, 2009Co-Authors: Elizabeth A Stier, Richa Tandon, Amy S Baranoski, Faye Huang, O VragrovicAbstract:Methods We performed a pilot, prospective, observational study on 100 HIV-infected women presenting for routine HIV care. Subjects were interviewed and underwent cervical and anal testing with cytology and HPV with Hybrid Capture 2 assay (Digene Corporation, Gaithersburg, MD). High resolution Anoscopy (HRA) or colposcopy were performed if indicated and subjects with high grade dysplasia were referred for treatment. Secondary analyses were performed to assess for associated risk factors for abnormal cervical or anal cytology or HPV infection such as CD4 Tcell count using SPSS for Windows, version 15.0.
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prevalence of perianal intraepithelial neoplasia in hiv infected patients referred for high resolution Anoscopy
Diseases of The Colon & Rectum, 2006Co-Authors: Caio Sergio Rizkallah Nahas, Oscar Lin, Martin R Weiser, Larissa K Temple, Douglas W Wong, Elizabeth A StierAbstract:This study was designed to describe perianal disease in a cohort of HIV-infected patients referred for high-resolution Anoscopy. A retrospective chart review was performed on 52 HIV-infected patients referred for high-resolution Anoscopy from 2001 to 2005. All patients underwent anal canal and perianal high-resolution Anoscopy in the office with biopsy of suspicious areas. Patients with high-grade intraepithelial perianal lesions underwent multiple biopsies under general anesthesia in the operating room to rule out malignancy. Of the 52 patients, 19 (37 percent) had perianal abnormalities noted on high-resolution Anoscopy and underwent punch biopsy. The mean duration of known HIV infection in these 19 patients (15 males) was 10.6 years, with 17 on highly active antiretroviral therapy for the last 3-month period. Mean CD4 count was 371 cells/μl. Office perianal biopsies diagnosed two patients with invasive squamous-cell carcinoma and nine with high-grade squamous intraepithelial lesion. Seven of the nine patients with perianal high-grade squamous intraepithelial lesion on office biopsy were submitted to multiple biopsies under general anesthesia. One of these seven had an occult perianal squamous-cell carcinoma. Perianal disease was common in this group of HIV-infected patients; 11 patients (21 percent of total) were diagnosed with squamous-cell carcinoma or high-grade squamous intraepithelial lesion. Because only 19 patients had clinically suspicious perianal lesions biopsied, this may be an underestimate. Our data suggest that anal canal neoplasia often is accompanied by perianal disease and illustrates the need for biopsy of any suspicious perianal lesions.
Jan M Prins - One of the best experts on this subject based on the ideXlab platform.
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detection rate of high grade squamous intraepithelial lesions as a quality assurance metric for high resolution Anoscopy in hiv positive men
Diseases of The Colon & Rectum, 2018Co-Authors: Matthijs Siegenbeek L Van Heukelom, Elske Marra, Irina Cairo, Arne Van Eeden, Maarten Schim F Van Der Loeff, Henry J C De Vries, Jan M PrinsAbstract:BACKGROUND High-resolution Anoscopy-guided biopsies are the gold standard for identifying anal intraepithelial neoplasia, but diagnosing high-grade squamous intraepithelial lesions depends on the skills of the anoscopist. OBJECTIVE This study aims to validate the high-grade squamous intraepithelial lesion detection rate as a quality assurance metric for high-resolution Anoscopy in HIV-positive men. DESIGN This is a retrospective study. SETTING This study was conducted at 3 HIV outpatient clinics in Amsterdam, The Netherlands. PATIENTS HIV-positive men who have sex with men were selected for this study. MAIN OUTCOME MEASURES We analyzed the high-grade squamous intraepithelial lesion detection rate per high-resolution Anoscopy, the mean number of biopsies taken, and the mean high-grade squamous intraepithelial lesion rate per biopsy in time-subsequent groups for 7 anoscopists performing high-resolution Anoscopy. RESULTS Seven anoscopists performed high-resolution Anoscopy in 1340 HIV-positive men who have sex with men. The overall high-grade squamous intraepithelial lesion detection rate for all 7 anoscopists combined increased significantly over time, from 27% to 40% (p < 0.001; OR, 1.15; 95% CI, 1.08-1.23 per 50 high-resolution anoscopies). The mean number of biopsies increased significantly from 1.4 (22% high-grade squamous intraepithelial lesions per biopsy) to 2.0 biopsies per patient (29% high-grade squamous intraepithelial lesions per biopsy) (p < 0.001). Three anoscopists showed a significant increase in proportion of high-grade squamous intraepithelial lesions per biopsy with increasing experience. LIMITATIONS There were statistically significant differences, with limited clinical significance, in the characteristics of patient populations between anoscopists and clinics. CONCLUSIONS We found significant variations in the high-grade squamous intraepithelial lesion detection rate among anoscopists performing high-resolution Anoscopy in HIV-positive men who have sex with men. The high-grade squamous intraepithelial lesion detection rate and mean high-grade squamous intraepithelial lesion rate per biopsy can be used as a quality assurance metric to follow up the learning curve of high-resolution anoscopists. See Video Abstract at http://links.lww.com/DCR/A555.
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high resolution Anoscopy clinical features of anal intraepithelial neoplasia in hiv positive men
Diseases of The Colon & Rectum, 2013Co-Authors: Olivier Richel, Jan M Prins, Nora D L Hallensleben, Alexander Kreuter, Carel J M Van Noesel, Henry J C De VriesAbstract:BACKGROUND:High-resolution Anoscopy is increasingly advocated to screen HIV+ men who have sex with men for anal cancer and its precursor lesions, anal intraepithelial neoplasia. A systematic comparison between clinical features and the histopathology of suspect lesions is lacking.OBJECTIVE:This stud
Henry J C De Vries - One of the best experts on this subject based on the ideXlab platform.
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detection rate of high grade squamous intraepithelial lesions as a quality assurance metric for high resolution Anoscopy in hiv positive men
Diseases of The Colon & Rectum, 2018Co-Authors: Matthijs Siegenbeek L Van Heukelom, Elske Marra, Irina Cairo, Arne Van Eeden, Maarten Schim F Van Der Loeff, Henry J C De Vries, Jan M PrinsAbstract:BACKGROUND High-resolution Anoscopy-guided biopsies are the gold standard for identifying anal intraepithelial neoplasia, but diagnosing high-grade squamous intraepithelial lesions depends on the skills of the anoscopist. OBJECTIVE This study aims to validate the high-grade squamous intraepithelial lesion detection rate as a quality assurance metric for high-resolution Anoscopy in HIV-positive men. DESIGN This is a retrospective study. SETTING This study was conducted at 3 HIV outpatient clinics in Amsterdam, The Netherlands. PATIENTS HIV-positive men who have sex with men were selected for this study. MAIN OUTCOME MEASURES We analyzed the high-grade squamous intraepithelial lesion detection rate per high-resolution Anoscopy, the mean number of biopsies taken, and the mean high-grade squamous intraepithelial lesion rate per biopsy in time-subsequent groups for 7 anoscopists performing high-resolution Anoscopy. RESULTS Seven anoscopists performed high-resolution Anoscopy in 1340 HIV-positive men who have sex with men. The overall high-grade squamous intraepithelial lesion detection rate for all 7 anoscopists combined increased significantly over time, from 27% to 40% (p < 0.001; OR, 1.15; 95% CI, 1.08-1.23 per 50 high-resolution anoscopies). The mean number of biopsies increased significantly from 1.4 (22% high-grade squamous intraepithelial lesions per biopsy) to 2.0 biopsies per patient (29% high-grade squamous intraepithelial lesions per biopsy) (p < 0.001). Three anoscopists showed a significant increase in proportion of high-grade squamous intraepithelial lesions per biopsy with increasing experience. LIMITATIONS There were statistically significant differences, with limited clinical significance, in the characteristics of patient populations between anoscopists and clinics. CONCLUSIONS We found significant variations in the high-grade squamous intraepithelial lesion detection rate among anoscopists performing high-resolution Anoscopy in HIV-positive men who have sex with men. The high-grade squamous intraepithelial lesion detection rate and mean high-grade squamous intraepithelial lesion rate per biopsy can be used as a quality assurance metric to follow up the learning curve of high-resolution anoscopists. See Video Abstract at http://links.lww.com/DCR/A555.
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high resolution Anoscopy clinical features of anal intraepithelial neoplasia in hiv positive men
Diseases of The Colon & Rectum, 2013Co-Authors: Olivier Richel, Jan M Prins, Nora D L Hallensleben, Alexander Kreuter, Carel J M Van Noesel, Henry J C De VriesAbstract:BACKGROUND:High-resolution Anoscopy is increasingly advocated to screen HIV+ men who have sex with men for anal cancer and its precursor lesions, anal intraepithelial neoplasia. A systematic comparison between clinical features and the histopathology of suspect lesions is lacking.OBJECTIVE:This stud
Daphne Garrett - One of the best experts on this subject based on the ideXlab platform.
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Original contributionHemorrhoid banding using videoendoscopic Anoscopy and a single-handed ligator: an effective, inexpensive alternative to endoscopic band ligation
The American Journal of Gastroenterology, 2000Co-Authors: William Dickey, Daphne GarrettAbstract:OBJECTIVE: We evaluated a technique of hemorrhoid banding using videoscopic Anoscopy and a single-handed ligator that offers substantial cost savings over endoscope-mounted devices. METHODS: Patients with rectal bleeding from grade II/III hemorrhoids had videoscopic Anoscopy, which provided a magnified view, allowing accurate localization of the hemorrhoids and the dentate line before banding, and a photographic record, if required. Banding was performed using a suction ligator that could be operated by one hand, allowing the other to control the anoscope. RESULTS: Of 39 patients with second- and third-degree hemorrhoids, 34 (87%) had no further bleeding after a single banding session and a further three had no recurrence after a second session. The only complications were pain (one patient) and infection (one patient). CONCLUSIONS: This method is convenient and effective, costing per procedure less than one-tenth of endoscope-mounted band ligators. We recommend its use in preference if magnified views and a photographic record are required. However, its cost and complexity, compared with traditional hemorrhoid banding, may mean that the latter is preferred in the office setting.
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Hemorrhoid banding using videoendoscopic Anoscopy and a single-handed ligator: an effective, inexpensive alternative to endoscopic band ligation.
The American journal of gastroenterology, 2000Co-Authors: William Dickey, Daphne GarrettAbstract:Abstract OBJECTIVE: We evaluated a technique of hemorrhoid banding using videoscopic Anoscopy and a single-handed ligator that offers substantial cost savings over endoscope-mounted devices. METHODS: Patients with rectal bleeding from grade II/III hemorrhoids had videoscopic Anoscopy, which provided a magnified view, allowing accurate localization of the hemorrhoids and the dentate line before banding, and a photographic record, if required. Banding was performed using a suction ligator that could be operated by one hand, allowing the other to control the anoscope. RESULTS: Of 39 patients with second- and third-degree hemorrhoids, 34 (87%) had no further bleeding after a single banding session and a further three had no recurrence after a second session. The only complications were pain (one patient) and infection (one patient). CONCLUSIONS: This method is convenient and effective, costing per procedure less than one-tenth of endoscope-mounted band ligators. We recommend its use in preference if magnified views and a photographic record are required. However, its cost and complexity, compared with traditional hemorrhoid banding, may mean that the latter is preferred in the office setting.