University of Texas Health Science Center at Houston

About: University of Texas Health Science Center at Houston is a education organization based out in Houston, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 27309 authors who have published 42520 publications receiving 2151596 citations. The organization is also known as: UTHealth & The UT Health Science Center at Houston.

Genetic basis for in vivo daptomycin resistance in enterococci

Abstract: Background Daptomycin is a lipopeptide with bactericidal activity that acts on the cell membrane of enterococci and is often used off-label to treat patients infected with vancomycin-resistant enterococci. However, the emergence of resistance to daptomycin during therapy threatens its usefulness. Methods We performed whole-genome sequencing and characterization of the cell envelope of a clinical pair of vancomycin-resistant Enterococcus faecalis isolates from the blood of a patient with fatal bacteremia; one isolate (S613) was from blood drawn before treatment and the other isolate (R712) was from blood drawn after treatment with daptomycin. The minimal inhibitory concentrations (MICs) of these two isolates were 1 and 12 μg per milliliter, respectively. Gene replacements were made to exchange the alleles found in isolate S613 with those in isolate R712. Results Isolate R712 had in-frame deletions in three genes. Two genes encoded putative enzymes involved in phospholipid metabolism, GdpD (which denotes gl...

Near-Infrared Fluorescence Imaging in Humans with Indocyanine Green: A Review and Update.

Abstract: Near-infrared (NIR) fluorescence imaging clinical studies have been reported in the literature with six different devices that employ various doses of indocyanine green (ICG) as a non-specific contrast agent. To date, clinical applications range from (i) angiography, intraoperative assessment of vessel patency, and tumor/metastasis delineation following intravenous administration of ICG, and (ii) imaging lymphatic architecture and function following subcutaneous and intradermal ICG administration. In the latter case, NIR fluorescence imaging may enable new discoveries associated with lymphatic function due to (i) a unique niche that is not met by any other conventional imaging technology and (ii) its exquisite sensitivity enabling high spatial and temporal resolution. Herein, we (i) review the basics of clinical NIR fluorescence imaging, (ii) survey the literature on clinical application of investigational devices using ICG fluorescent contrast, (iii) provide an update of non-invasive dynamic lymphatic imaging conducted with our FDPM device, and finally, (iv) comment on the future NIR fluorescence imaging for non-invasive and intraoperative use given recent demonstrations showing capabilities for imaging following microdose administration of contrast agent.

Structure of the F-actin–tropomyosin complex

Abstract: Electron cryomicroscopy reveals the three-dimensional structure of F-actin at a resolution of 3.7 A in complex with tropomyosin at a resolution of 6.5 A; the stabilizing interactions and the effects of disease-causing mutants are also investigated. Filamentous actin (F-actin) — a main component of the cytoskeleton — is the major protein of thin filaments in the muscle. The binding of the motor protein myosin to F-actin is mediated by another protein called tropomyosin, which also binds to F-actin in smooth muscle and in non-muscle cells, stabilizing and regulating these filaments. Using electron cryomicroscopy, Stefan Raunser and colleagues have obtained the first high-resolution, three-dimensional structure of F-actin in complex with tropomyosin. The structure reveals the interactions that stabilize the F-actin and sheds light on the possible effect of prominent disease-causing mutations. Comparison of the F-actin structure with the crystal structure of monomeric (G)-actin reveals conformational changes associated with filament formation. Filamentous actin (F-actin) is the major protein of muscle thin filaments, and actin microfilaments are the main component of the eukaryotic cytoskeleton. Mutations in different actin isoforms lead to early-onset autosomal dominant non-syndromic hearing loss1, familial thoracic aortic aneurysms and dissections2, and multiple variations of myopathies3. In striated muscle fibres, the binding of myosin motors to actin filaments is mainly regulated by tropomyosin and troponin4,5. Tropomyosin also binds to F-actin in smooth muscle and in non-muscle cells and stabilizes and regulates the filaments there in the absence of troponin6. Although crystal structures for monomeric actin (G-actin) are available7, a high-resolution structure of F-actin is still missing, hampering our understanding of how disease-causing mutations affect the function of thin muscle filaments and microfilaments. Here we report the three-dimensional structure of F-actin at a resolution of 3.7 A in complex with tropomyosin at a resolution of 6.5 A, determined by electron cryomicroscopy. The structure reveals that the D-loop is ordered and acts as a central region for hydrophobic and electrostatic interactions that stabilize the F-actin filament. We clearly identify map density corresponding to ADP and Mg2+ and explain the possible effect of prominent disease-causing mutants. A comparison of F-actin with G-actin reveals the conformational changes during filament formation and identifies the D-loop as their key mediator. We also confirm that negatively charged tropomyosin interacts with a positively charged groove on F-actin. Comparison of the position of tropomyosin in F-actin–tropomyosin with its position in our previously determined F-actin–tropomyosin–myosin structure8 reveals a myosin-induced transition of tropomyosin. Our results allow us to understand the role of individual mutations in the genesis of actin- and tropomyosin-related diseases and will serve as a strong foundation for the targeted development of drugs.

Breast cancer on the world wide web: cross sectional survey of quality of information and popularity of websites

Abstract: Objectives: To determine the characteristics of popular breast cancer related websites and whether more popular sites are of higher quality. Design: The search engine Google was used to generate a list of websites about breast cancer. Google ranks search results by measures of link popularity—the number of links to a site from other sites. The top 200 sites returned in response to the query “breast cancer” were divided into “more popular” and “less popular” subgroups by three different measures of link popularity: Google rank and number of links reported independently by Google and by AltaVista (another search engine). Main outcome measures: Type and quality of content. Results: More popular sites according to Google rank were more likely than less popular ones to contain information on ongoing clinical trials (27% v 12%, P=0.01), results of trials (12% v 3%, P=0.02), and opportunities for psychosocial adjustment (48% v 23%, P Conclusions: Popularity of websites is associated with type rather than quality of content. Sites that include content correlated with popularity may best meet the public9s desire for information about breast cancer. What is already known on this topic Patients are using the world wide web to search for health information Breast cancer is one of the most popular search topics Characteristics of popular websites may reflect the information needs of patients What this study adds Type rather than quality of content correlates with popularity of websites Measures of quality correlate with accuracy of medical information