Gut CD4+ T cell phenotypes are a continuum molded by microbes, not by TH archetypes

CD4+ effector lymphocytes (Teff) are traditionally classified by the cytokines they produce. To determine the states that Teff cells actually adopt in frontline tissues in vivo, we applied single-cell transcriptome and chromatin analyses to colonic Teff cells in germ-free or conventional mice or in mice after challenge with a range of phenotypically biasing microbes. Unexpected subsets were marked by the expression of the interferon (IFN) signature or myeloid-specific transcripts, but transcriptome or chromatin structure could not resolve discrete clusters fitting classic helper T cell (TH) subsets. At baseline or at different times of infection, transcripts encoding cytokines or proteins commonly used as TH markers were distributed in a polarized continuum, which was functionally validated. Clones derived from single progenitors gave rise to both IFN-γ- and interleukin (IL)-17-producing cells. Most of the transcriptional variance was tied to the infecting agent, independent of the cytokines produced, and chromatin variance primarily reflected activities of activator protein (AP)-1 and IFN-regulatory factor (IRF) transcription factor (TF) families, not the canonical subset master regulators T-bet, GATA3 or RORγ

Tight Regulation of Srs2 Helicase Activity Is Crucial for Proper Functioning of DNA Repair Mechanisms

Proper DNA damage repair is one of the most vital and fundamental functions of every cell. Several different repair mechanisms exist to deal with various types of DNA damage, in various stages of the cell cycle and under different conditions. Homologous recombination is one of the most important repair mechanisms in all organisms. Srs2, a regulator of homologous recombination, is a DNA helicase involved in DNA repair, cell cycle progression and genome integrity. Srs2 can remove Rad51 from ssDNA, and is thought to inhibit unscheduled recombination. However, Srs2 has to be precisely regulated, as failure to do so is toxic and can lead to cell death. We noticed that a very slight elevation of the levels of Srs2 (by addition of a single extra copy of the SRS2 gene) leads to hyper-sensitivity of yeast cells to methyl methanesulfonate (MMS, a DNA damaging agent). This effect is seen in haploid, but not in diploid, cells. We analyzed the mechanism that controls haploid/diploid sensitivity and arrived to the conclusion that the sensitivity requires the activity of RAD59 and RDH54, whose expression in diploid cells is repressed. We carried out a mutational analysis of Srs2 to determine the regions of the protein required for the sensitization to genotoxins. Interestingly, Srs2 needs the HR machinery and its helicase activity for its toxicity, but does not need to dismantle Rad51. Our work underscores the tight regulation that is required on the levels of Srs2 activity, and the fact that Srs2 helicase activity plays a more central role in DNA repair than the ability of Srs2 to dismantle Rad51 filaments

Are Hounsfield Unit Measurements of Bony Absorption Changes in Cholesteatoma Helpful?

Abstract Introduction High-resolution computed tomography (HRCT) scans of the temporal bone are used to assess the bony erosion of the middle-ear structures whenever cholesteatoma is suspected. Objective To study the differences in HRCT Hounsfield unit (HU) index measurements of middle-ear bony structures between an ears with and without cholesteatoma. Methods A retrospective study of 59 patients who underwent surgery due to unilateral cholesteatoma. The HRCT HU index of the scutum, of three middle-ear ossicles, of the lateral semicircular canal (LSCC), and of the fallopian canal was measured in both ears. A comparison was made between the cholesteatoma and the non-cholesteatomatous ear (control). All measurements were conducted by an otolaryngologist. To assess the interobserver bias, 10% of the samples were randomly and independently assessed by another otolaryngologist and a neuroradiologist who were blinded. Results The average HU index was lower in the ear with cholesteatoma when compared with the non-cholesteatomatous ear. While the differences were statistically significant regarding the measurements of the scutum (516.02 ± 311.693 versus 855.64 ± 389.999; p = 0.001), the malleus (1049.44 ± 481.765 versus 1413.47 ± 313.376; p = 0.01), and the incus (498.03 ± 264.184 versus 714.25 ± 405.631; p = 0.001), the differences in the measurements of the LSCC (1042.34 ± 301.066 versus 1154.53 ± 359.609; p = 0.69) and of the fallopian canal (467.19 ± 221.556 versus 543.51 ± 263.573; p = 0.108) were not significantly different between both groups. The stapes was immeasurable in both groups due to its small size. Conclusion Hounsfield unit index measurements are a useful tool that may aid in the diagnosis of early-stage cholesteatoma.</jats:p

Adult Otogenic Meningitis in the Pneumococcal Conjugated Vaccines Era

Abstract Introduction Streptococcus pneumoniae is a major pathogen of otogenic meningitis (OgM), the most commonly reported intra-cranial complication of otitis media (OM). Objectives To study the changes in adult OgM patients in the pneumococcal conjugated vaccines (PCVs) era. Methods Retrospective cohort of adults presenting with concurrent OM and meningitis in a secondary medical care center between 2005 and 2015. Data collected included demographics, OM-related symptoms, cerebrospinal fluid (CSF) and ear culture results, pre- and during hospitalization antibiotic treatment, imaging findings, and complications. We compared the pre-PCV years (2005–2009) with the post-PCV years (2010–2015). Outcomes were 1) incidence of all-cause adult OgM from the total meningitis cases; 2) impact of PCVs on the clinical presentation of OgM and bacteriology. Results Otogenic meningitis was diagnosed in 26 out of 45 (58%) cases of all-cause meningitis admissions. Of those, 10 (38%) were male, with a mean age of 62.4 years old. Ear-related signs and symptoms were documented in 70% of the patients, and OgM was diagnosed following imaging studies in 6 out of 26 (23%) patients. All of the patients received intravenous antibiotic therapy, and 7 (27%) patients required surgical interventions: 6 required myringotomy and 1 required mastoidectomy. There were 12 (46%) patients in the pre-PCV years and 14 (56%) in the post-PCV years. The positive pneumococcal CSF and ear culture rates remained high and unchanged (∼ 75%). There were no significant changes in the clinical presentation or mortality rates. Conclusion Micro-otoscopy should be included in the routine work-up of any suspected adult meningitis, because OgM is underdiagnosed. Unlike their impact on pediatric otitis media, PCVs did not change the epidemiology and bacteriology of OgM.</jats:p

Inkjet printed fluorescent nanorod layers exhibit superior optical performance over quantum dots

Printed fluorescent nanorod layers maintain high fluorescence efficiency and stable color performance, while quantum dots exhibit quenching and color shifts.</p