3,952 research outputs found
Systematic assessment of HER2/neu in gynecologic neoplasms, an institutional experience.
BackgroundHER2/neu overexpression and/or amplification has been widely studied in a number of solid tumors, primarily in the breast. In gynecologic neoplasms, determination of HER2/neu status has not been well studied as a predictive biomarker in anti-HER2/neu treatment.MethodsWe systematically evaluated the HER2/neu reactions by immunohistochemistry and fluorescent in situ hybridization in malignant gynecologic neoplasms as experienced in our institution.ResultsThe HER2/neu overexpression or amplification occurred in 8 % of the cancers of the gynecological organs in our series. Majority of the HER2/neu overexpression and/or amplification occurred in clear cell (27 %) and serous (11 %) carcinomas. HER2/neu positivity was also seen in undifferentiated as well as in mixed clear cell and serous carcinomas. Discordant IHC and FISH results (positive by FISH but not IHC) was seen in 2 cases. Majority of the HER2/neu overexpression and/or amplification occurs in the endometrium rather than the ovary. Heterogeneity of the HER2/neu by IHC staining was in < 2 % of the tumors in our series.ConclusionsWe recommend the HER2/neu studies on Müllerian carcinomas of clear cell, serous, and undifferentiated types, particularly when they arise in the endometrium. Since there are some discordant IHC/FISH results, we also propose performing the HER2/neu testing by FISH when the IHC score is less than 3 +
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Omega 3 Fatty Acid Inhibition of Inflammatory Cytokine-Mediated Connexin43 Regulation in the Heart
Background: The proinflammatory cytokine , which increases in the heart post myocardial infarction (MI), has been shown to cause loss of Connexin43 (Cx43) function, an event known to underlie formation of the arrhythmogenic substrate. Omega 3 Fatty acids exhibit antiarrhythmic properties and impact signaling. We hypothesize that Omega-3 fatty acids prevent arrhythmias in part, by inhibiting signaling thus maintaining functional Cx43 channels. Methods: Rat neonatal myocytes or Madin-Darby Canine Kidney Epithelial (MDCK) cells grown in media in the absence (Ctr) or presence of docosahexaenoic acid (DHA, an Omega-3 Fatty acid) were treated with activated . We determined Cx43 channel function using a dye spread assay. Western blot and immunostaining were used to examine Cx43 levels/localization and downstream effectors of . In addition we used a murine model of MI for 24 h to determine the impact of an Omega-3 fatty acid enriched diet on Cx43 levels/localization post MI. Results: significantly inhibited Cx43 function in Ctr cells . However, DHA-treated cells remained highly coupled in the presence of . Additionally, western blot showed that treatment caused a 38.5% downregulation of Cx43 which was completely abolished in DHA-treated cells . Examination of the downstream modulator of , showed that while hypoxia caused translocation of to the nucleus, this was inhibited by DHA. Additionally we found that a diet enriched in Omega-3 Fatty acids inhibited lateralization of Cx43 in the post-MI murine heart as well as limited activation of fibroblasts which would lead to decreased fibrosis overall. Conclusions: Omega 3 Fatty acid treatment inhibited -stimulated loss of Cx43 protein, and more importantly, inhibited loss of Cx43 function by inhibiting translocation of . In the intact heart a diet enriched in Omega 3 Fatty Acids limited loss of Cx43 at the intercalated disk in the heart following MI. These data suggest that one of cardio-protective mechanisms by which Omega 3 Fatty acids work includes prevention of the pro-arrhythmic loss of Cx43 post MI and the attenuation of cardiac fibrosis after injury
Consistency between ARPES and STM measurements on SmB
Strongly correlated topological surface states are promising platforms for
next-generation quantum applications, but they remain elusive in real
materials. The correlated Kondo insulator SmB is one of the most promising
candidates, with theoretically predicted heavy Dirac surface states supported
by transport and scanning tunneling microscopy (STM) experiments. However, a
puzzling discrepancy appears between STM and angle-resolved photoemission
(ARPES) experiments on SmB. Although ARPES detects spin-textured surface
states, their velocity is an order of magnitude higher than expected, while the
Dirac point -- the hallmark of any topological system -- can only be inferred
deep within the bulk valence band. A significant challenge is that SmB
lacks a natural cleavage plane, resulting in ordered surface domains limited to
10s of nanometers. Here we use STM to show that surface band bending can shift
energy features by 10s of meV between domains. Starting from our STM spectra,
we simulate the full spectral function as an average over multiple domains with
different surface potentials. Our simulation shows excellent agreement with
ARPES data, and thus resolves the apparent discrepancy between large-area
measurements that average over multiple band-shifted domains and
atomically-resolved measurements within a single domain
Discrete Element Method Model of Elastic Fiber Uniaxial Compression
A flexible fiber model based on the discrete element method (DEM) is
presented and validated for the simulation of uniaxial compression of flexible
fibers in a cylindrical container. It is found that the contact force models in
the DEM simulations have a significant impact on compressive forces exerted on
the fiber bed. Only when the geometry-dependent normal contact force model and
the static friction model are employed, the simulation results are in good
agreement with experimental results. Systematic simulation studies show that
the compressive force initially increases and eventually saturates with an
increase in the fiber-fiber friction coefficient, and the fiber-fiber contact
forces follow a similar trend. The compressive force and lateral
shear-to-normal stress ratio increase linearly with increasing fiber-wall
friction coefficient. In uniaxial compression of frictional fibers, more static
friction contacts occur than dynamic friction contacts with static friction
becoming more predominant as the fiber-fiber friction coefficient increases.Comment: 30 pages, 14 figures, submitted for publicatio
High-throughput screening in larval zebrafish identifies novel potent sedative-hypnotics
BACKGROUND: Many general anesthetics were discovered empirically, but primary screens to find new sedative-hypnotics in drug libraries have not used animals, limiting the types of drugs discovered. The authors hypothesized that a sedative-hypnotic screening approach using zebrafish larvae responses to sensory stimuli would perform comparably to standard assays, and efficiently identify new active compounds.
METHODS:
The authors developed a binary outcome photomotor response assay for zebrafish larvae using a computerized system that tracked individual motions of up to 96 animals simultaneously. The assay was validated against tadpole loss of righting reflexes, using sedative-hypnotics of widely varying potencies that affect various molecular targets. A total of 374 representative compounds from a larger library were screened in zebrafish larvae for hypnotic activity at 10 µM. Molecular mechanisms of hits were explored in anesthetic-sensitive ion channels using electrophysiology, or in zebrafish using a specific reversal agent.
RESULTS:
Zebrafish larvae assays required far less drug, time, and effort than tadpoles. In validation experiments, zebrafish and tadpole screening for hypnotic activity agreed 100% (n = 11; P = 0.002), and potencies were very similar (Pearson correlation, r > 0.999). Two reversible and potent sedative-hypnotics were discovered in the library subset. CMLD003237 (EC50, ~11 µM) weakly modulated γ-aminobutyric acid type A receptors and inhibited neuronal nicotinic receptors. CMLD006025 (EC50, ~13 µM) inhibited both N-methyl-D-aspartate and neuronal nicotinic receptors.
CONCLUSIONS:
Photomotor response assays in zebrafish larvae are a mechanism-independent platform for high-throughput screening to identify novel sedative-hypnotics. The variety of chemotypes producing hypnosis is likely much larger than currently known.This work was supported by grants from Shanghai Jiaotong University School of Medicine, Shanghai, China, and the Chinese Medical Association, Beijing, China (both to Dr. Yang). The Department of Anesthesia, Critical Care and Pain Medicine of Massachusetts General Hospital, Boston, Massachusetts, supported this work through a Research Scholars Award and an Innovation Grant (both to Dr. Forman). Contributions to this research from the Boston University Center for Molecular Discovery, Boston, Massachusetts (to Drs. Porco, Brown, Schaus, and Xu, and to Mr. Trilles), were supported by a grant from the National Institutes of Health, Bethesda, Maryland (grant No. R24 GM111625). (Shanghai Jiaotong University School of Medicine, Shanghai, China; Chinese Medical Association, Beijing, China; Department of Anesthesia, Critical Care and Pain Medicine of Massachusetts General Hospital, Boston, Massachusetts; R24 GM111625 - National Institutes of Health, Bethesda, Maryland)Accepted manuscript2019-09-0
Cell Death of Melanophores in Zebrafish trpm7 Mutant Embryos Depends on Melanin Synthesis
Transient receptor potential melastatin 7 (TRPM7) is a broadly expressed, non-selective cation channel. Studies in cultured cells implicate TRPM7 in regulation of cell growth, spreading, and survival. However, zebrafish trpm7 homozygous mutants display death of melanophores and temporary paralysis, but no gross morphological defects during embryonic stages. This phenotype implies that melanophores are unusually sensitive to decreases in Trpm7 levels, a hypothesis we investigate here. We find that pharmacological inhibition of caspases does not rescue melanophore viability in trpm7 mutants, implying that melanophores die by a mechanism other than apoptosis. Consistent with this possibility, ultrastructural analysis of dying melanophores in trpm7 mutants reveals abnormal melanosomes and evidence of a ruptured plasma membrane, indicating that cell death occurs by necrosis. Interestingly, inhibition of melanin synthesis largely prevents melanophore cell death in trpm7 mutants. These results suggest that melanophores require Trpm7 in order to detoxify intermediates of melanin synthesis. We find that unlike TRPM1, TRPM7 is expressed in human melanoma cell lines, indicating that these cells may also be sensitized to reduction of TRPM7 levels
High-Resolution Spectroscopic Study of Extremely Metal-Poor Star Candidates from the SkyMapper Survey
The SkyMapper Southern Sky Survey is carrying out a search for the most
metal-poor stars in the Galaxy. It identifies candidates by way of its unique
filter set that allows for estimation of stellar atmospheric parameters. The
set includes a narrow filter centered on the Ca II K 3933A line, enabling a
robust estimate of stellar metallicity. Promising candidates are then confirmed
with spectroscopy. We present the analysis of Magellan-MIKE high-resolution
spectroscopy of 122 metal-poor stars found by SkyMapper in the first two years
of commissioning observations. 41 stars have [Fe/H] <= -3.0. Nine have [Fe/H]
<= -3.5, with three at [Fe/H] ~ -4. A 1D LTE abundance analysis of the elements
Li, C, Na, Mg, Al, Si, Ca, Sc, Ti, Cr, Mn, Co, Ni, Zn, Sr, Ba and Eu shows
these stars have [X/Fe] ratios typical of other halo stars. One star with low
[X/Fe]
[X/Fe values appears to be "Fe-enhanced," while another star has an extremely
large [Sr/Ba] ratio: >2. Only one other star is known to have a comparable
value. Seven stars are "CEMP-no" stars ([C/Fe] > 0.7, [Ba/Fe] < 0). 21 stars
exhibit mild r-process element enhancements (0.3 <=[Eu/Fe] < 1.0), while four
stars have [Eu/Fe] >= 1.0. These results demonstrate the ability to identify
extremely metal-poor stars from SkyMapper photometry, pointing to increased
sample sizes and a better characterization of the metal-poor tail of the halo
metallicity distribution function in the future.Comment: Minor corrections to text, missing data added to Tables 3 and 4;
updated to match published version. Complete tables included in sourc
Identification of critical residues of influenza neuraminidase in viral particle release
BACKGROUND: Influenza neuraminidase (NA) is essential for virus release from its host cells and it is one of the targets for structure-based antiviral drug design.
RESULTS: In this report, we established a pseudoviral particle release assay to study NA function, which is based on lentiviral particles pseudotyped with influenza glycoproteins HA and NA as a surrogate system. Through an extensive molecular analysis, we sought to characterize important residues governing NA function. We identified five residues of NA, 234, 241, 257, 286 and 345, four of which (except 345) map away from the active site of NA when projected onto the three-dimensional structure of avian influenza H5N1 NA, and substitutions of these residues adversely affected the NA-mediated viral particle release, suggesting that these residues are critical for NA enzymatic activity.
CONCLUSION: Through extensive chimeric and mutational analyses, we have identified several residues, which map away from the active site and are critical for NA function. These findings provide new insights into NA-mediated pseudoviral particle release and may have important implications in drug design and therapeutics against influenza infection
The developmental course of illicit substance use from age 12 to 22: links with depressive, anxiety, and behavior disorders at age 18
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72027/1/j.1469-7610.2008.01915.x.pd
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