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1.
HNO ; 2024 Jun 11.
Artigo em Alemão | MEDLINE | ID: mdl-38861032

RESUMO

BACKGROUND: Very early bilateral cochlear implant (CI) provision is today's established standard for children. Therefore, the assessment of preverbal and verbal performance in very early stages of development is becoming increasingly important. Performance data from cohorts of children were evaluated and presented based on diagnostic assessment using chronological age (CA) and hearing age (HA). METHODS: The present study, as part of a retrospective multicentre study, included 4 cohorts (N = 72-233) of children with bilateral CI without additional disabilities. Their results in the German parent questionnaires Elternfragebögen zur Früherkennung von Risikokindern(ELFRA­1 and ELFRA-2) subdivided for CA and HA were statistically analysed. The data were also analysed in terms of mono-/bilingualism and age at CI provision. RESULTS: Overall, verbal performance in relation to CA was lower than in relation to HA. Preverbal skills were largely CA appropriate. Children with bi-/multilingual language acquisition performed significantly lower. Verbal performance in ELFRA­2 referenced to CA was negatively correlated with age at CI provision. CONCLUSION: In the case of early CI provision, CA should be the preferred reference mark in preverbal and verbal assessment in order to obtain exact individual performance levels and avoid bias in results. The percentiles determined are of limited use as generally valid reference values to which the individual performance of bilaterally implanted children could be compared. Further multicentre studies should be initiated.

2.
Otol Neurotol ; 45(5): 502-506, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38509805

RESUMO

OBJECTIVE: The objective of this study is to examine the influence of electrode array design on the position of the basal-most electrode in cochlear implant (CI) surgery and therefore the stimulability of the basal cochlea. Specifically, we evaluated the angular insertion depth of the basal-most electrode in perimodiolar and straight electrode arrays in relation to postoperative speech perception. MATERIALS AND METHODS: We conducted a retrospective analysis of 495 patients between 2013 and 2018 using the Cochlear™ Contour Advance® (CA), Cochlear™ Slim Straight® (SSA), or Cochlear™ Slim Modiolar® (SMA) electrode arrays, as well as the MED-EL Flex24 (F24), MED-EL Flex28 (F28), and MED-EL FlexSoft (F31.5) electrode arrays. Cochlear size and the position of the basal-most electrode were measured using rotational tomography or cone beam computed tomography, and the results were compared with postoperative speech perception in monosyllables and numbers. RESULTS: The straight electrode arrays, specifically the F31.5 (31.5 mm length) and the F28 (28 mm length), exhibited a significantly greater angular insertion depth of the basal-most electrode. No significant correlation was found between cochlear morphology measurements and the position of the basal-most electrode artifact. Cochleostomy-inserted electrode arrays showed a significantly higher insertion depth of the basal-most electrode. Nevertheless, the position of the basal-most electrode did not have a significant impact on postoperative speech perception. CONCLUSION: Straight electrode arrays with longer lengths achieved deeper angular insertion depths of the basal-most electrode. Cochlear morphology does not have a substantial influence on the position of basal-most electrode. The study confirms that the basal area of the cochlea, responsible for high-frequency range during acoustic stimulation, is not the primary region for speech understanding via electrical stimulation with CI.


Assuntos
Cóclea , Implante Coclear , Implantes Cocleares , Percepção da Fala , Humanos , Estudos Retrospectivos , Percepção da Fala/fisiologia , Masculino , Implante Coclear/métodos , Feminino , Pessoa de Meia-Idade , Adulto , Cóclea/cirurgia , Cóclea/diagnóstico por imagem , Cóclea/anatomia & histologia , Idoso , Adulto Jovem , Adolescente , Criança , Pré-Escolar , Desenho de Prótese , Idoso de 80 Anos ou mais , Eletrodos Implantados , Período Pós-Operatório
3.
J Clin Med ; 13(3)2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38337340

RESUMO

Background: The cochlear implant (CI) is an established treatment option for patients with inadequate speech understanding and insufficient aided scores. Nevertheless, reliable predictive models and specific therapy goals regarding achievable speech understanding are still lacking. Method: In this retrospective study, 601 cases of CI fittings between 2005 and 2021 at the University Medical Center Freiburg were analyzed. We investigated the preoperative unaided maximum word recognition score (mWRS) as a minimum predictor for post-interventional scores at 65 dB SPL, WRS65(CI). The WRS65(CI) was compared with the preoperative-aided WRS, and a previously published prediction model for the WRS65(CI) was reviewed. Furthermore, the effect of duration of hearing loss, duration of HA fitting, and etiology on WRS65(CI) were investigated. Results: In 95.5% of the cases, a significant improvement in word recognition was observed after CI. WRS65(CI) achieved or exceeded mWRS in 97% of cases. Etiology had a significant impact on WRS65(CI). The predicted score was missed by more than 20 percentage points in 12.8% of cases. Discussion: Our results confirmed the minimum prediction via mWRS. A more precise prediction of the expected WRS65(CI) is possible. The etiology of hearing loss should be considered in the indication and postoperative care to achieve optimal results.

4.
J Phys Chem Lett ; 14(35): 7848-7853, 2023 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-37625113

RESUMO

The presence of chemisorbed oxygen on the Cu(111) surface is known to strongly reduce the activation barrier for water dissociation as compared to bare Cu(111). Here, we present direct experimental evidence for the hydrogen abstraction mechanism responsible for the facile H2O dissociation on an O/Cu(111) surface using reflection absorption infrared spectroscopy (RAIRS) in combination with isotopically labeled reactants. We also observe that chemisorbed hydroxyl species produced by water dissociation on the O/Cu(111) surface undergo an efficient hydrogen atom transfer from trapped water molecules, leading to the rapid replacement of the initial oxygen isotope coverage and the detection of only a single hydroxyl isotopologue on the surface, in apparent contradiction with the hydrogen abstraction mechanism. In the presence of Cu2O oxide islands on the O/Cu(111) surface, water dissociation occurs selectively at the edges of those islands, leading to the self-assembly of isotopically ordered structures.

5.
Front Chem ; 11: 1238711, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37588512

RESUMO

Recent state-to-state experiments of methane scattering from Ni(111) and graphene-covered Ni(111) combined with quantum mechanical simulations suggest an intriguing correlation between the surface-induced vibrational energy redistribution (SIVR) during the molecule/surface scattering event and the catalytic activity for methane dissociation of the target surface (Werdecker, Phys. Rev. Res., 2020, 2, 043251). Herein, we report new quantum state and angle-resolved measurements for methane scattering from Ni(111) and Au(111) probing the extent of ν3→ν1 antisymmetric-to-symmetric conversion of methane stretching motion for two surfaces with different catalytic activities. Consistent with the expectations, the extent of SIVR occurring on the more catalytically active Ni(111) surface, as measured by the ν1:ν3 scattered population ratio, is found to be several times stronger than that on the more inert Au(111) surface. We also present additional insights on the rovibrational scattering dynamics contained in the angle- and state-resolved data. The results together highlight the power of state-resolved scattering measurements as a tool for investigating methane-surface interactions.

6.
J Chem Phys ; 158(21)2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37260006

RESUMO

We describe a novel ultrahigh vacuum state-to-state molecule/surface scattering apparatus with quantum state preparation of the incident molecular beam and angle-resolved quantum state detection of the scattered molecules. State-resolved detection is accomplished using a tunable mid-infrared laser source combined with a cryogenic bolometer detector and is applicable to any molecule with an infrared-active vibrational transition. Results on rotationally inelastic scattering of CH4 methane from a Ni(111) surface and NiO(111)/Ni(111) oxide film, obtained by the new apparatus, are presented. Molecules scattering from the oxidized surface, compared to those scattering from the bare nickel surface, are more highly excited rotationally and scatter into a broader distribution of angles. The internal alignment of molecular rotation is in addition found to be stronger in molecules scattering from the bare surface. Furthermore, the maxima of the state-resolved angular distributions shift toward and away from surface normal with increasing rotational quantum number J for the oxidized and bare surface, respectively. Finally, the rotational state populations produced in scattering from the oxidized surface are well-described by a Boltzmann distribution, while those produced in scattering from the bare surface exhibit large deviations from their best-fit Boltzmann distributions. These results point toward a marked enhancement in molecule-surface collisional energy exchange induced by oxidation of the nickel surface.

7.
Eur Arch Otorhinolaryngol ; 280(11): 4811-4817, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37093292

RESUMO

INTRODUCTION: The most common sensorineural disorder in humans is hearing impairment and approximately 60% of prelingual hearing disorders are genetic. Especially parents with a congenital deaf child want to know as early as possible whether their second born child has the same genetic defect or not. The aim of this study is to demonstrate that postnatal genetic umbilical cord analysis is both the earliest detection possibility and sufficient. METHODS: We included first born children with severe hearing impairment that underwent cochlear implantation. All included patients were analyzed genetically and exhibited mutations of either DFNB1 loci or SLC26A4 gene. Additionally, the umbilical cord of the sibling underwent genetic analysis to detect hereditary genetic mutations as early as possible. RESULTS: 49 newborn children out of 22 families were included in this study. Genetic analysis revealed clinical relevant mutations in all first born children and in four siblings via umbilical cord analysis. All patients who have been diagnosed with a relevant genetic mutation that caused severe hearing impairment underwent hearing rehabilitation via cochlear implant surgery. CONCLUSION: This study demonstrates the sufficient and early as possible detection of known genetically hearing disorders via umbilical cord analysis. In case of a known familial genetic hearing disorder, it is advisable to analyze newborn siblings for the corresponding genetic defect as soon as possible, to be able to plan and initiate clinical care for the patient as early as possible. It is also extremely important for the parents to obtain clear information about the auditory status of the newborn.


Assuntos
Implante Coclear , Implantes Cocleares , Surdez , Perda Auditiva Neurossensorial , Perda Auditiva , Recém-Nascido , Humanos , Perda Auditiva/diagnóstico , Perda Auditiva/genética , Perda Auditiva/cirurgia , Audição , Mutação , Surdez/diagnóstico , Surdez/genética , Surdez/reabilitação , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/genética , Perda Auditiva Neurossensorial/congênito
8.
Commun Biol ; 6(1): 287, 2023 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-36934128

RESUMO

Regulated intramembrane proteolysis (RIP) describes the protease-dependent cleavage of transmembrane proteins within the hydrophobic core of cellular membranes. Intramembrane-cleaving proteases (I-CliPs) that catalyze these reactions are found in all kingdoms of life and are involved in a wide range of cellular processes, including signaling and protein homeostasis. I-CLiPs are multispanning membrane proteins and represent challenging targets in structural and enzyme biology. Here we introduce iCLiPSpy, a simple assay to study I-CLiPs in vivo. To allow easy detection of enzyme activity, we developed a heme-binding reporter based on TNFα that changes color after I-CLiP-mediated proteolysis. Co-expression of the protease and reporter in Escherichia coli (E. coli) results in white or green colonies, depending on the activity of the protease. As a proof of concept, we use this assay to study the bacterial intramembrane-cleaving zinc metalloprotease RseP in vivo. iCLiPSpy expands the methodological repertoire for identifying residues important for substrate binding or activity of I-CLiPs and can in principle be adapted to a screening assay for the identification of inhibitors or activators of I-CLiPs, which is of great interest for proteases being explored as biomedical targets.


Assuntos
Proteínas de Escherichia coli , Peptídeo Hidrolases , Peptídeo Hidrolases/genética , Peptídeo Hidrolases/metabolismo , Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Endopeptidases/genética , Endopeptidases/metabolismo , Proteínas de Membrana/metabolismo , Heme/metabolismo
9.
J Phys Chem C Nanomater Interfaces ; 126(49): 20886-20891, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36561201

RESUMO

Methylidyne, CH(ads), adsorbed on a Pt(211) surface and its interaction with chemisorbed hydrogen atoms was studied by reflection absorption infrared spectroscopy (RAIRS). Methylidyne was formed on Pt(211) by methane dissociation from a molecular beam followed by thermal decomposition of the methane dissociation products. CH(ads) was detected by RAIRS via its symmetric C-H stretch vibration resulting in three discrete absorption peaks in the region of 2950-2970 cm-1. While the frequencies of the three C-H stretch peaks remain fixed, their relative intensities depend on the H(ads) co-coverage. This differs markedly from what was observed previously for the RAIR spectra of CH(ads) adsorbed on Pt(111) by the group of Trenary,1 who observed a single C-H stretch peak, which showed a continuous blue shift with increasing H(ads) coverage. Based on our experimental results and density functional theory (DFT) calculations, we propose that the three discrete absorption peaks on Pt(211) are due to the adsorption of methylidyne on the steps of Pt(211) forming one-dimensional rows of adsorbates. Depending on the H(ads) coverage, the CH(ads) species on the step sites can have either zero, one, or two neighboring H(ads) atoms, leading to three different vibrational C-H stretch frequencies and a reversible shift in relative peak intensity depending on the H(ads) coverage.

10.
Sci Rep ; 12(1): 8052, 2022 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-35577824

RESUMO

Ocean acidification is a threat to deep-sea corals and could lead to dramatic and rapid loss of the reef framework habitat they build. Weakening of structurally critical parts of the coral reef framework can lead to physical habitat collapse on an ecosystem scale, reducing the potential for biodiversity support. The mechanism underpinning crumbling and collapse of corals can be described via a combination of laboratory-scale experiments and mathematical and computational models. We synthesise data from electron back-scatter diffraction, micro-computed tomography, and micromechanical experiments, supplemented by molecular dynamics and continuum micromechanics simulations to predict failure of coral structures under increasing porosity and dissolution. Results reveal remarkable mechanical properties of the building material of cold-water coral skeletons of 462 MPa compressive strength and 45-67 GPa stiffness. This is 10 times stronger than concrete, twice as strong as ultrahigh performance fibre reinforced concrete, or nacre. Contrary to what would be expected, CWCs retain the strength of their skeletal building material despite a loss of its stiffness even when synthesised under future oceanic conditions. As this is on the material length-scale, it is independent of increasing porosity from exposure to corrosive water or bioerosion. Our models then illustrate how small increases in porosity lead to significantly increased risk of crumbling coral habitat. This new understanding, combined with projections of how seawater chemistry will change over the coming decades, will help support future conservation and management efforts of these vulnerable marine ecosystems by identifying which ecosystems are at risk and when they will be at risk, allowing assessment of the impact upon associated biodiversity.


Assuntos
Antozoários , Animais , Antozoários/química , Recifes de Corais , Ecossistema , Concentração de Íons de Hidrogênio , Oceanos e Mares , Água do Mar/química , Água , Microtomografia por Raio-X
11.
Eur Arch Otorhinolaryngol ; 279(1): 149-158, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33566175

RESUMO

PURPOSE: The aim of the study was to compare long-term results after 1 year in patients with single-sided deafness (SSD) who were fitted with different hearing aids. The participants tested contralateral routing of signals (CROS) hearing aids and bone-anchored hearing systems (BAHS). They were also informed about the possibility of a cochlear implant (CI) and chose one of the three devices. We also investigated which factors influenced the choice of device. METHODS: Prospective study with 89 SSD participants who were divided into three groups by choosing BAHS, CROS, or CI. All participants received test batteries with both objective hearing tests (speech perception in noise and sound localisation) and subjective questionnaires. RESULTS: 16 participants opted for BAHS-, 13 for CROS- and 30 for CI-treatment. The greater the subjective impairment caused by SSD, the more likely patients were to opt for surgical treatment (BAHS or CI). The best results in terms of speech perception in noise (especially when sound reaches the deaf ear and noise the hearing ear), sound localization, and subjective results were achieved with CI. CONCLUSION: The best results regarding the therapy of SSD are achieved with a CI, followed by BAHS. This was evident both in objective tests and in the subjective questionnaires. Nevertheless, an individual decision is required in each case as to which SSD therapy option is best for the patient. Above all, the patient's subjective impairment and expectations should be included in the decision-making process.


Assuntos
Implante Coclear , Implantes Cocleares , Surdez , Auxiliares de Audição , Perda Auditiva Unilateral , Localização de Som , Percepção da Fala , Surdez/cirurgia , Audição , Perda Auditiva Unilateral/diagnóstico , Perda Auditiva Unilateral/cirurgia , Testes Auditivos , Humanos , Estudos Prospectivos , Resultado do Tratamento
12.
Eur Arch Otorhinolaryngol ; 279(9): 4257-4267, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34778920

RESUMO

PURPOSE: The aim of this study is to examine the scalar dislocation rate in straight and perimodiolar electrode arrays in relation to cochlear morphology. Furthermore, we aim to analyze the specific dislocation point of electrode arrays depending on their design and shape and to correlate these results to postoperative speech perception. METHODS: We conducted a comparative analysis of patients (ears: n = 495) implanted between 2013 and 2018 with inserted perimodiolar or straight electrode arrays from Cochlear™ or MED-EL. CBCT (cone beam computed tomography) was used to determine electrode array position (scalar insertion, intra-cochlear dislocation, point of dislocation and angular insertion depth). Furthermore, cochlear morphology was measured. The postoperative speech discrimination was compared regarding electrode array dislocation, primary scalar insertion and angular insertion depth. RESULTS: The electrode array with the highest rate of primary SV insertions was the CA; the electrode array with the highest rate of dislocations out of ST was the FlexSoft. We did not find significantly higher dislocation rates in cochleostomy-inserted arrays. The angle of dislocation was electrode array design-specific. A multivariate nonparametric analysis revealed that the dislocation of the electrode array has no significant influence on postoperative speech perception. Nevertheless, increasing angular insertion depth significantly reduced postoperative speech perception for monosyllables. CONCLUSION: This study demonstrates the significant influence of electrode array design on scalar location, dislocation and the angle of dislocation itself. Straight and perimodiolar electrode arrays differ from each other regarding both the rate and place of dislocation. Insertion via cochleostomy does not lead to increased dislocation rates in any of the included electrode arrays. Furthermore, speech perception is significantly negatively influenced by angular insertion depth.


Assuntos
Implante Coclear , Implantes Cocleares , Percepção da Fala , Cóclea/cirurgia , Implante Coclear/efeitos adversos , Implante Coclear/métodos , Implantes Cocleares/efeitos adversos , Tomografia Computadorizada de Feixe Cônico/métodos , Humanos
14.
J Phys Chem Lett ; 12(45): 11164-11169, 2021 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-34757753

RESUMO

Reflection-absorption infrared spectroscopy (RAIRS) is widely used to identify molecular adsorbates on metals during surface chemical reactions, but the interpretation of RAIRS data can be difficult with experiment alone. Here, we reveal from first-principles calculations the origin of the contrasting RAIRS spectra of methyl adsorbed on Pt(111) and Ni(111). We find that the dynamic dipole associated with the symmetric C-H stretch vibration of CH3 along surface normal is significant on Pt(111) but negligibly small on Ni(111), explaining the strong IR activity in the former and the absence of any RAIRS peaks in the latter. This difference is correlated to different charge transfer patterns between metals and the adsorbate, which are determined by the different preferred adsorption sites of methyl on the two surfaces. This work highlights the need of electronic structure calculations in interpreting RAIRS spectra of adsorbates on metal surfaces.

15.
J Phys Chem Lett ; 12(30): 7252-7260, 2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34313445

RESUMO

The probability for dissociation of molecules on metal surfaces, which often controls the rate of industrially important catalytic processes, can depend strongly on how energy is partitioned in the incident molecule. There are many example systems where the addition of vibrational energy promotes reaction more effectively than the addition of translational energy, but for rotational pre-excitation similar examples have not yet been discovered. Here, we make an experimentally testable theoretical prediction that adding energy to the rotation of HCl can promote its dissociation on Au(111) 20 times more effectively than increasing its translational energy. In the underlying mechanism, the molecule's initial rotational motion allows it to pass through a critical region of the reaction path, where this path shows a strong and nonmonotonic dependence on the molecular orientation.

16.
Laryngoscope ; 131(11): E2764-E2769, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34142721

RESUMO

OBJECTIVES/HYPOTHESIS: The prevalence of tympanostomy tube surgery (TTS) in patients with a cleft deformity was investigated, in relation to cleft width and cleft type. STUDY DESIGN: Retrospective review of medical health records. METHODS: Retrospective review of medical health records. Seventy-eight patients with non-syndromic cleft deformity of the palate and/or alveolus and lip between 2003 and 2017 were investigated. All available medical documents were analyzed. The study group was divided into subgroups: 1) patients with isolated cleft palate (CP) and patients with a cleft palate with cleft lip and alveolus (CLP). 2) According to Veau's classification (I-IV), further subgroups were defined. Cleft width was measured using plaster cast models. RESULTS: TTS was performed in 55% of the patients (n = 43). Considering Veau's classification, TTS was conducted as follows: Veau I 65.2% (n = 15/23), Veau II 55.0% (n = 11/20), Veau III 47.6% (n = 10/21), and Veau IV 50.0% (n = 7/14). Cleft classifications, maxillary arch width, and absolute/relative cleft width had no statistical impact on TTS occurrence. Although no significant correlation could be found, patients in our study group with CP (Veau I and II) underwent TTS more often (60.5%, n = 26/43) than patients with CPL (Veau III and IV; 48.6%, n = 17/35) during a three-year follow-up. CONCLUSION: None of the cleft characteristics examined had a significant impact on the proportion of patients who received TTS. Nevertheless, patients with lower Veau classification and CP received tympanostomy tubes more often. Therefore, otolaryngologists and pediatricians treating children with cleft palate should maintain a high level of suspicion for chronic middle ear effusion, even in patients with small clefts. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:E2764-E2769, 2021.


Assuntos
Encéfalo/anormalidades , Fenda Labial/complicações , Fissura Palatina/complicações , Ventilação da Orelha Média/estatística & dados numéricos , Otite Média com Derrame/cirurgia , Encéfalo/patologia , Estudos de Casos e Controles , Moldes Cirúrgicos/normas , Fenda Labial/classificação , Fenda Labial/diagnóstico , Fenda Labial/patologia , Fenda Labial/cirurgia , Fissura Palatina/classificação , Fissura Palatina/diagnóstico , Fissura Palatina/patologia , Fissura Palatina/cirurgia , Arco Dental/anatomia & histologia , Feminino , Seguimentos , Perda Auditiva/diagnóstico , Perda Auditiva/etiologia , Humanos , Lactente , Masculino , Maxila/anatomia & histologia , Ventilação da Orelha Média/métodos , Otite Média com Derrame/complicações , Otite Média com Derrame/diagnóstico , Otorrinolaringologistas , Pediatras , Prevalência , Estudos Retrospectivos
17.
Eur Arch Otorhinolaryngol ; 278(9): 3245-3255, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33079248

RESUMO

PURPOSE: The purpose of this retrospective study was to investigate the outcome and critical age of cochlear implantation in congenital single-sided deafness (SSD). METHODS: 11 children with congenital SSD were implanted with a cochlear implant (CI). Auditory performance was measured through the results of speech discrimination, subjective assessment by the Categories of auditory performance (CAP) score, the Speech, Spatial and Qualities scale questionnaire (SSQ) and the German version of the IOI-HA [Internationales Inventar zur Evaluation von Hörgeräten (IIEH, version for CI)]. RESULTS: Long-term follow-up [median: 3 years and 5 months (3;5 years)] revealed that nine children use their CI (> 8 h/day) and two became nonusers. In children aged below 3;2 years at surgery, there was a substantial long-term increase in speech discrimination and subjective benefit. Children over 4;4 years of age at CI surgery improved partially in audiological/subjective measurements. Among children above 5 years, the SSQ score did not improve despite further slight improvement in speech discrimination long-term. CONCLUSION: Our data suggest a critical age for CI surgery below 3 years in children with congenital SSD for successful hearing rehabilitation. It is mandatory to identify children with SSD as early as bilaterally deaf children.


Assuntos
Implante Coclear , Implantes Cocleares , Surdez , Perda Auditiva Unilateral , Percepção da Fala , Criança , Pré-Escolar , Surdez/cirurgia , Perda Auditiva Unilateral/cirurgia , Humanos , Estudos Retrospectivos , Resultado do Tratamento
18.
J Phys Chem B ; 124(41): 9061-9078, 2020 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-32954729

RESUMO

The metabotropic glutamate receptor (mGluR) 2 plays a key role in the central nervous system. mGluR2 has been shown to be regulated by its surrounding lipid environment, especially by cholesterol, by an unknown mechanism. Here, using a combination of biochemical approaches, photo-cross-linking experiments, and molecular dynamics simulations we show the interaction of cholesterol with at least two, but potentially five more, preferential sites on the mGluR2 transmembrane domain. Our simulations demonstrate that surface matching, rather than electrostatic interactions with specific amino acids, is the main factor defining cholesterol localization. Moreover, the cholesterol localization observed here is similar to the sterol-binding pattern previously described in silico for other members of the mGluR family. Biochemical assays suggest little influence of cholesterol on trafficking or dimerization of mGluR2. Nevertheless, simulations revealed a significant reduction of residue-residue contacts together with an alteration in the internal mechanical stress at the cytoplasmic side of the helical bundle when cholesterol was present in the membrane. These alterations may be related to destabilization of the basal state of mGluR2. Due to the high sequence conservation of the transmembrane domains of mGluRs, the molecular interaction of cholesterol and mGluR2 described here is also likely to be relevant for other members of the mGLuR family.


Assuntos
Receptores de Glutamato Metabotrópico , Aminoácidos , Colesterol
19.
Phys Chem Chem Phys ; 22(31): 17448-17459, 2020 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-32725003

RESUMO

-The combination of quantum state-specific reactant preparation by infrared laser pumping with surface-site-resolved detection of chemisorbed reaction products by Reflection Absorption Infrared Spectroscopy (RAIRS) enables highly detailed studies of molecule/surface reactivity. In this perspective, we review the methodologies developed for simultaneous quantumstate and surface-site-resolved reactivity measurements and their application towards the chemisorption of methane on stepped and kinked platinum surfaces. We demonstrate that RAIRS allows for surface-site-resolved detection of methane dissociation, which serves to measure surface-site-resolved product uptake curves, sticking probabilities, and dissociation barrier heights. For the dissociation of C-H stretch excited singly deuterated CH3D on a stepped Pt surface such as Pt(211), RAIRS was used to detect bond selectivity in methane chemisorption and to reveal how the bond-selective dissociation proceeds from the step to the terrace sites with increasing incident kinetic energy of the CH3D reactant. Extension to site-selective RAIRS detection of methane dissociation to other vicinal surfaces such as Pt(210), Pt(531), and Pt(110)-(2 × 1) is also presented.

20.
FEBS Lett ; 594(14): 2240-2253, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32394429

RESUMO

Dimerization of the small GTPase Arf is prerequisite for the scission of COPI-coated transport vesicles. Here, we quantify the monomer/dimer equilibrium of Arf within the membrane and show that after membrane scission, Arf dimers are restricted to donor membranes. By hydrogen exchange mass spectrometry, we define the interface of activated dimeric Arf within its switch II region. Single amino acid exchanges in this region reduce the propensity of Arf to dimerize. We suggest a mechanism of membrane scission by which the dimeric form of Arf is segregated to the donor membrane. Our data are consistent with the previously reported absence of dimerized Arf in COPI vesicles and could explain the presence of one single scar-like noncoated region in each COPI vesicle.


Assuntos
Fator 1 de Ribosilação do ADP/química , Fator 1 de Ribosilação do ADP/metabolismo , Vesículas Revestidas pelo Complexo de Proteína do Envoltório/metabolismo , Membrana Celular/metabolismo , Multimerização Proteica , Sítios de Ligação , Humanos , Bicamadas Lipídicas/metabolismo , Modelos Moleculares
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