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1.
Aging Dis ; 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38739932

RESUMO

The dynamic interaction between the brain and the skin is termed the 'skin-brain axis.' Changes in the skin not only reflect conditions in the brain but also exert direct and indirect effects on the brain. Interestingly, the connection between the skin and brain is crucial for understanding aging and neurodegenerative diseases. Several studies have shown an association between Alzheimer's disease (AD) and various skin disorders, such as psoriasis, bullous pemphigoid, and skin cancer. Previous studies have shown a significantly increased risk of new-onset AD in patients with psoriasis. In contrast, skin cancer may reduce the risk of developing AD. Accumulating evidence suggests an interaction between skin disease and AD; however, AD-associated pathological changes mediated by the skin-brain axis are not yet clearly defined. While some studies have reported on the diagnostic implications of the skin-brain axis in AD, few have discussed its potential therapeutic applications. In this review, we address the pathological changes mediated by the skin-brain axis in AD. Furthermore, we summarize (1) the diagnostic implications elucidated through the role of the skin-brain axis in AD and (2) the therapeutic implications for AD based on the skin-brain axis. Our review suggests that a potential therapeutic approach targeting the skin-brain axis will enable significant advances in the treatment of AD.

2.
J Adv Res ; 2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-38030129

RESUMO

INTRODUCTION: Cisplatin is a life-saving anticancer compound used to treat multiple solid malignant tumors, while it causes permanent hearing loss. There is no known cure, and the FDA has not approved any preventative treatment for cisplatin-based ototoxicity. OBJECTIVES: This study investigated whether the carbon monoxide (CO)-releasing tricarbonyldichlororuthenium (II) dimer, CORM-2, reverses cisplatin-induced hearing impairment and reduces cisplatin accumulation in the mouse inner ear. METHODS: Male 6-week-old BALB/c mice were randomly assigned to one of the following groups: control (saline-treated, i.p.), CORM-2 only (30 mg/kg, i.p., four doses), cisplatin only (20 mg/kg, i.p., one dose), and CORM-2 + cisplatin, to determine whether cisplatin-based hearing impairment was alleviated by CORM-2 treatment. RESULTS: Our results revealed CORM-2 significantly attenuated cisplatin-induced hearing loss in young adult mice. CORM-2 co-treatment significantly decreased platinum accumulation in the inner ear and activated the plasma membrane repair system of the stria vascularis. Moreover, CORM-2 co-treatment significantly decreased cisplatin-induced inflammation, apoptosis, and cochlear necroptosis. Because the stria vascularis is the likely cochlear entry point of cisplatin, we next focused on the microvasculature. Cisplatin induced increased extravasation of a chromatic tracer (fluorescein isothiocyanate [FITC]-dextran, MW 75 kDa) around the cochlear microvessels at 4 days post-treatment; this extravasation was completely inhibited by CORM-2 co-therapy. CORM-2 co-treatment effectively maintained the integrity of stria vascularis components including endothelial cells, pericytes, and perivascular-resident macrophage-type melanocytes. CONCLUSION: CORM-2 co-therapy substantially protects against cisplatin-induced ototoxicity by reducing platinum accumulation and toxic cellular stress responses. These data indicate that CORM-2 co-treatment may be translated into clinical strategy to reduce cisplatin-induced hearing loss.

3.
Front Chem ; 9: 781838, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34966721

RESUMO

Nickel phosphide (Ni-P) films as a catalytic cathode for the hydrogen evolution reaction (HER) of a water splitting were fabricated by a pulse-reverse electrodeposition technique. The electrochemical behaviors for the electrodeposition of Ni-P were investigated by the characterization of peaks in a cyclic voltammogram. The composition of the electrodeposited Ni-P alloys was controlled by adjusting duty cycles of the pulse-reverse electrodeposition. The HER electrocatalytic properties of the Ni-P electrodeposits with an amorphous phase as a function of phosphorous contents existing in Ni-P were electrochemically characterized by the analysis of overpotentials, Tafel slopes, and electrochemical impedance spectrometry. Additionally, the elemental Ni-embedded crystalline Ni3P was prepared by an annealing process with the amorphous Ni69P31 electrodeposit with high contents of phosphorus. The crystalline structure with Ni inclusions in the matrix of Ni3P was formed by the precipitation of excess Ni. The electrocatalytic properties of crystalline Ni3P with elemental Ni inclusions were also investigated by electrochemical characterization.

4.
Int J Mol Sci ; 22(16)2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34445504

RESUMO

Although previous studies continuously report an increased risk of hearing loss in diabetes patients, the impact of the disease on the inner ear remains unexplored. Herein, we examine the pathophysiology of diabetes-associated hearing impairment and cochlear synaptopathy in a mouse model of diabetes. Male B6.BKS(D)-Leprdb/J (db/db, diabetes) and heterozygote (db/+, control) mice were assigned into each experimental group (control vs. diabetes) based on the genotype and tested for hearing sensitivity every week from 6 weeks of age. Each cochlea was collected for histological and biological assays at 14 weeks of age. The diabetic mice exerted impaired hearing and a reduction in cochlear blood flow and C-terminal-binding protein 2 (CtBP2, a presynaptic ribbon marker) expression. Ultrastructural images revealed severely damaged mitochondria from diabetic cochlea accompanied by a reduction in Cytochrome c oxidase subunit 4 (COX4) and CR6-interacting factor 1 (CRIF1). The diabetic mice presented significantly decreased levels of platelet endothelial cell adhesion molecule (PECAM-1), B-cell lymphoma 2 (BCL-2), and procaspase-9, but not procaspase-8. Importantly, significant changes were not found in necroptotic programmed cell death markers (receptor-interacting serine/threonine-protein kinase 1, RIPK1; RIPK3; and mixed lineage kinase domain-like pseudokinase, MLKL) between the groups. Taken together, diabetic hearing loss is accompanied by synaptopathy, microangiopathy, damage to the mitochondrial structure/function, and activation of the intrinsic apoptosis pathway. Our results imply that mitochondrial dysfunction is deeply involved in diabetic hearing loss, and further suggests the potential benefits of therapeutic strategies targeting mitochondria.


Assuntos
Diabetes Mellitus Experimental/complicações , Perda Auditiva/fisiopatologia , Mitocôndrias/ultraestrutura , Receptores para Leptina/genética , Animais , Apoptose , Biomarcadores/metabolismo , Cóclea/irrigação sanguínea , Cóclea/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Modelos Animais de Doenças , Regulação para Baixo , Perda Auditiva/etiologia , Perda Auditiva/genética , Perda Auditiva/metabolismo , Humanos , Masculino , Camundongos , Microscopia Eletrônica de Transmissão , Mitocôndrias/metabolismo
5.
Front Neurosci ; 14: 583097, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33071750

RESUMO

Although the major causative factors of Alzheimer's disease (AD) are the accumulation of amyloid ß and hyperphosphorylated tau, AD can also be caused by metabolic dysfunction. The major clinical symptom of AD is cognitive dysfunction. However, AD is also accompanied by various secondary symptoms such as depression, sleep-wake disturbances, and abnormal eating behaviors. Interestingly, the orexigenic hormone ghrelin has been suggested to have beneficial effects on AD-related metabolic syndrome and secondary symptoms. Ghrelin improves lipid distribution and alters insulin sensitivity, effects that are hypothesized to delay the progression of AD. Furthermore, ghrelin can relieve depression by enhancing the secretion of hormones such as serotonin, noradrenaline, and orexin. Moreover, ghrelin can upregulate the expression of neurotrophic factors such as brain-derived neurotrophic factor and modulate the release of proinflammatory cytokines such as tumor necrosis factor α and interleukin 1ß. Ghrelin alleviates sleep-wake disturbances by increasing the levels of melatonin, melanin-concentrating hormone. Ghrelin reduces the risk of abnormal eating behaviors by increasing neuropeptide Y and γ-aminobutyric acid. In addition, ghrelin increases food intake by inhibiting fatty acid biosynthesis. However, despite the numerous studies on the role of ghrelin in the AD-related pathology and metabolic disorders, there are only a few studies that investigate the effects of ghrelin on secondary symptoms associated with AD. In this mini review, our purpose is to provide the insights of future study by organizing the previous studies for the role of ghrelin in AD-related pathology and metabolic disorders.

6.
Int J Mol Sci ; 21(12)2020 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-32630597

RESUMO

Alzheimer's disease (AD) is the most common type of dementia. AD involves major pathologies such as amyloid-ß (Aß) plaques and neurofibrillary tangles in the brain. During the progression of AD, microglia can be polarized from anti-inflammatory M2 to pro-inflammatory M1 phenotype. The activation of triggering receptor expressed on myeloid cells 2 (TREM2) may result in microglia phenotype switching from M1 to M2, which finally attenuated Aß deposition and memory loss in AD. Low-dose ionizing radiation (LDIR) is known to ameliorate Aß pathology and cognitive deficits in AD; however, the therapeutic mechanisms of LDIR against AD-related pathology have been little studied. First, we reconfirm that LDIR (two Gy per fraction for five times)-treated six-month 5XFAD mice exhibited (1) the reduction of Aß deposition, as reflected by thioflavins S staining, and (2) the improvement of cognitive deficits, as revealed by Morris water maze test, compared to sham-exposed 5XFAD mice. To elucidate the mechanisms of LDIR-induced inhibition of Aß accumulation and memory loss in AD, we examined whether LDIR regulates the microglial phenotype through the examination of levels of M1 and M2 cytokines in 5XFAD mice. In addition, we investigated the direct effects of LDIR on lipopolysaccharide (LPS)-induced production and secretion of M1/M2 cytokines in the BV-2 microglial cells. In the LPS- and LDIR-treated BV-2 cells, the M2 phenotypic marker CD206 was significantly increased, compared with LPS- and sham-treated BV-2 cells. Finally, the effect of LDIR on M2 polarization was confirmed by detection of increased expression of TREM2 in LPS-induced BV2 cells. These results suggest that LDIR directly induced phenotype switching from M1 to M2 in the brain with AD. Taken together, our results indicated that LDIR modulates LPS- and Aß-induced neuroinflammation by promoting M2 polarization via TREM2 expression, and has beneficial effects in the AD-related pathology such as Aß deposition and memory loss.


Assuntos
Doença de Alzheimer/metabolismo , Microglia/metabolismo , Microglia/efeitos da radiação , Doença de Alzheimer/fisiopatologia , Peptídeos beta-Amiloides/metabolismo , Animais , Anti-Inflamatórios/farmacologia , Biomarcadores/metabolismo , Encéfalo/metabolismo , Transtornos Cognitivos/metabolismo , Disfunção Cognitiva/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Lipopolissacarídeos/farmacologia , Masculino , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Modelos Biológicos , Fenótipo , Radiação Ionizante , Receptores Imunológicos/metabolismo
7.
Int J Mol Sci ; 21(10)2020 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-32456197

RESUMO

Alzheimer's disease (AD) is the most common cause of dementia. The neuropathological features of AD include amyloid-ß (Aß) deposition and hyperphosphorylated tau accumulation. Although several clinical trials have been conducted to identify a cure for AD, no effective drug or treatment has been identified thus far. Recently, the potential use of non-pharmacological interventions to prevent or treat AD has gained attention. Low-dose ionizing radiation (LDIR) is a non-pharmacological intervention which is currently being evaluated in clinical trials for AD patients. However, the mechanisms underlying the therapeutic effects of LDIR therapy have not yet been established. In this study, we examined the effect of LDIR on Aß accumulation and Aß-mediated pathology. To investigate the short-term effects of low-moderate dose ionizing radiation (LMDIR), a total of 9 Gy (1.8 Gy per fraction for five times) were radiated to 4-month-old 5XFAD mice, an Aß-overexpressing transgenic mouse model of AD, and then sacrificed at 4 days after last exposure to LMDIR. Comparing sham-exposed and LMDIR-exposed 5XFAD mice indicated that short-term exposure to LMDIR did not affect Aß accumulation in the brain, but significantly ameliorated synaptic degeneration, neuronal loss, and neuroinflammation in the hippocampal formation and cerebral cortex. In addition, a direct neuroprotective effect was confirmed in SH-SY5Y neuronal cells treated with Aß1-42 (2 µM) after single irradiation (1 Gy). In BV-2 microglial cells exposed to Aß and/or LMDIR, LMDIR therapy significantly inhibited the production of pro-inflammatory molecules and activation of the nuclear factor-kappa B (NF-κB) pathway. These results indicate that LMDIR directly ameliorated neurodegeneration and neuroinflammation in vivo and in vitro. Collectively, our findings suggest that the therapeutic benefits of LMDIR in AD may be mediated by its neuroprotective and anti-inflammatory effects.


Assuntos
Doença de Alzheimer/radioterapia , Irradiação Craniana/métodos , Animais , Linhagem Celular Tumoral , Córtex Cerebral/metabolismo , Córtex Cerebral/efeitos da radiação , Feminino , Humanos , Camundongos , NF-kappa B/metabolismo , Doses de Radiação , Radiação Ionizante
8.
J Vet Sci ; 20(5): e50, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31565893

RESUMO

Porcine endogenous retroviruses (PERVs) integrate into germline DNA as proviral genome that enables vertical transmission from parents to their offspring. The provirus usually survives as part of the host genome rather than as an infectious agent, but may become pathogenic if it crosses species barriers. Therefore, replication-competent PERV should be controlled through selective breeding or knockout technologies. Two microRNAs (miRNAs), dual LTR1 and LTR2, were selected to inhibit the expression of PERV in primary porcine kidney cells. The inhibition efficiency of the miRNAs was compared based on their inhibition of different PERV regions, specifically long terminal repeats (LTRs), gag, pol, and env. Gene expression was quantified using real-time polymerase chain reaction and the C-type reverse transcriptase (RT) activity was determined. The messenger RNA (mRNA) expression of the PERV LTR and env regions was determined in HeLa cells co-cultured with primary porcine kidney cells. The mRNA expression of the LTR, gag, pol, and env regions of PERV was dramatically inhibited by dual miRNA from 24 to 144 h after transfection, with the highest inhibition observed for the LTR and pol regions at 120 h. Additionally, the RT activity of PERV in the co-culture experiment of porcine and human cells was reduced by 84.4% at the sixth passage. The dual LTR 1+2 miRNA efficiently silences PERV in primary porcine kidney cells.


Assuntos
Retrovirus Endógenos/fisiologia , MicroRNAs/metabolismo , Infecções por Retroviridae/veterinária , Doenças dos Suínos/genética , Animais , Linhagem Celular , Retrovirus Endógenos/genética , Rim , Infecções por Retroviridae/genética , Infecções por Retroviridae/virologia , Suínos , Doenças dos Suínos/virologia , Sequências Repetidas Terminais/fisiologia
9.
Acta Otolaryngol ; 139(2): 122-128, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30762451

RESUMO

BACKGROUND: Paper patching, a method that places cigarette paper over the most mobile quadrants of the tympanic membrane, is one of the treatment options for patulous eustachian tube (PET). AIMS/OBJECTIVES: The objective of this study was to compare the outcomes of two different treatment strategies for PET. MATERIAL AND METHODS: Twenty-three patients underwent paper patching of the tympanic membrane and 16 patients were treated with nasal saline irrigation with or without ipratropium bromide nasal spray. Medical records were reviewed for resolution of PET symptoms as categorical variables (complete remission, partial remission, or no improvement) with a minimum follow-up of 3 months. RESULTS: Immediately after undergoing paper patching, 20 of the 23 patients (87.0%) reported complete remission (CR). The percentage of CR after paper patching was 82.6% at 1 month and 65.2% at 3 months. A greater percentage of patients reported CR of aural symptoms in the paper patching group than in the nasal irrigation group at both 1 and 3 months after treatment (p < .05). CONCLUSIONS AND SIGNIFICANCE: Repetitive paper patching resolves aural discomfort in most PET patients for at least 3 months and can be considered as a first-line treatment option for PET in the outpatient setting.


Assuntos
Tratamento Conservador/métodos , Otopatias/terapia , Tuba Auditiva/anormalidades , Papel , Adulto , Idoso , Estudos de Coortes , Otopatias/diagnóstico , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Lavagem Nasal/métodos , Estudos Retrospectivos , Resultado do Tratamento
10.
Clin Exp Otorhinolaryngol ; 12(1): 27-32, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29909612

RESUMO

OBJECTIVES: The purpose of this study were to evaluate the clinical characteristics of temporal bone metastasis (TBM) and to determine whether the characteristics differed according to primary malignancy. METHODS: We retrospectively analyzed data on 20 patients diagnosed with TBM between January 2000 and January 2017. Demographics, the period from diagnosis of primary malignancy to TBM diagnosis, the period from TBM diagnosis to death, the type and staging of primary malignancy, otologic manifestations, and TBM sites were assessed. After the primary malignancies were divided into solid cancers and hematologic malignancies, each parameter was compared between the two groups. RESULTS: The most common primary malignancy with TBM was lung cancer (45%). The most common otologic symptoms and signs were facial palsy (30.5%) and hearing loss (30.5%). The temporal squama (23%) and the facial nerve (20%) were the most commonly involved. Most TBMs occurred late in the disease process after the primary malignancy first metastasized to other organs. Hematologic malignancies metastasized significantly more frequently to the external auditory canal and the middle ear/mastoid compared to solid cancers (P=0.001 and P=0.004, respectively). CONCLUSION: If otologic manifestations such as facial palsy and hearing loss are presented in patients at advanced stages of malignancy, TBM of primary malignancy should be suspected. In addition, hematologic malignancies tend to metastasize to the external auditory canal and the middle ear cleft more commonly than solid cancers do.

11.
Lasers Med Sci ; 34(2): 367-375, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30105484

RESUMO

Gene therapy is the delivery of a therapeutic gene into target cells to treat disorders by replacing disease-causing mutated genes with healthy ones. Gene therapy of the inner ear has been recently described, with applications for sensorineural hearing loss. However, gene delivery to the location of the inner ear, and thus efficacy of therapy, is challenging. Photobiomodulation (PBM) with a low-level laser has been suggested to have a therapeutic effect and has the potential to augment gene therapy. To investigate whether PBM improves the rate of adenovirus (Ad)-mediated viral delivery, we compared low-level laser therapy (LLLT) and non-LLLT HEI-OC1 cells treated with an Ad viral vector carrying green fluorescent protein (GFP). Cultured HEI-OC1 cells were divided into six groups: no treatment control, LLLT only, 1 µL Ad-GFP, 3 µL Ad-GFP, 1 µL Ad-GFP + LLLT, and 3 µL Ad-GFP + LLLT (LLLT: 808 nm at 15 mW for 15 min). Cells were irradiated twice: at 2 h and again at 24 h. A nonparametric Mann-Whitney U test was used to statistically analyze differences between the control and treatment groups. The viral inoculations used in this study did not change the amount of viable HEI-OC1 cells (N = 4-8). The 1 µL Ad-GFP + LLLT and 3 µL Ad-GFP + LLLT groups showed an increased density of GFP-positive cells compared to 1 µL and 3 µL Ad-GFP cells (N = 5-8, 1 µL: p = 0.0159; 3 µL: p = 0.0168,). The quantitative analysis of the epifluorescence of the 1 µL Ad-GFP + LLLT, and 3 µL Ad-GFP + LLLT groups revealed increased GFP expression/cell compared to 1 µL and 3 µL Ad-GFP cells (N = 6-15, 1 µL: p = 0.0082; 3 µL: p = 0.0012). The RT-qPCR results were consistent (N = 4-5, p = 0.0159). These findings suggest that PBM may enhance the gene delivery of Ad-mediated viral transduction, and the combination of the two may be a promising tool for gene therapy for sensorineural hearing loss.


Assuntos
Adenoviridae/metabolismo , Células Ciliadas Auditivas/metabolismo , Terapia com Luz de Baixa Intensidade , Transdução Genética/métodos , Animais , Linhagem Celular , Sobrevivência Celular , Fluorescência , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Camundongos
12.
Clin Otolaryngol ; 43(6): 1535-1540, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30091180

RESUMO

OBJECTIVES: To evaluate the radiologic parameters related to success of round window (RW) approach for cochlear implantation (CI). DESIGN: A retrospective cohort study. SETTING: Academic-tertiary centre. PARTICIPANTS: Eighty-four consecutive patients without inner ear anomaly who underwent CI with the intent of the RW approach were included. The RW approach was performed through the facial recess after posterior tympanotomy (RW group). When the RW approach was not possible despite maximum effort to expose the RW, promontory cochleostomy (PC) was performed (PC group). MAIN OUTCOME MEASURES: The following radiologic parameters were compared between the two groups: (a) Width of the facial recess, (b) oblique distance between the cochlear basal turn (CBT) and facial nerve (FN), (c) anteroposterior distance between the posterior margin of the RW and FN and (d) angle between the EAC and CBT. RESULTS: Seventy patients (83.3%) were implanted using the RW approach, and 14 patients (16.7%) underwent the PC approach for CI. The anteroposterior distance between the posterior margin of the RW and FN and the angle between the EAC and CBT in the RW group were significantly longer and wider than those in the PC group (P < 0.001 and P = 0.001, respectively). Multivariate analysis revealed that these two parameters were independent parameters for success of the RW approach. CONCLUSIONS: The distance between the posterior margin of the RW and FN and the angle between the EAC and CBT are associated with success of RW approach. Therefore, preoperative radiologic analysis of the two parameters might help CI surgeons to select RW approach.


Assuntos
Implante Coclear/métodos , Perda Auditiva Neurossensorial/cirurgia , Audição/fisiologia , Janela da Cóclea/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Timpanoplastia/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Seguimentos , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/fisiopatologia , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Osso Temporal/diagnóstico por imagem , Resultado do Tratamento , Adulto Jovem
13.
Biomed Res Int ; 2018: 8137614, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30009175

RESUMO

Sensorineural hearing loss is caused by the loss of sensory hair cells (HCs) or a damaged afferent nerve pathway to the auditory cortex. The most common option for the treatment of sensorineural hearing loss is hearing rehabilitation using hearing devices. Various kinds of hearing devices are available but, despite recent advancements, their perceived sound quality does not mimic that of the "naïve" cochlea. Damage to crucial cochlear structures is mostly irreversible and results in permanent hearing loss. Cochlear HC regeneration has long been an important goal in the field of hearing research. However, it remains challenging because, thus far, no medical treatment has successfully regenerated cochlear HCs. Recent advances in genetic modulation and developmental techniques have led to novel approaches to generating HCs or protecting against HC loss, to preserve hearing. In this review, we present and review the current status of two different approaches to restoring or protecting hearing, gene therapy, including the newly introduced CRISPR/Cas9 genome editing, and stem cell therapy, and suggest the future direction.


Assuntos
Terapia Genética , Células Ciliadas Auditivas Internas , Perda Auditiva Neurossensorial/terapia , Transplante de Células-Tronco , Animais , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Células Ciliadas Auditivas , Humanos , Camundongos , Ratos
14.
Materials (Basel) ; 10(10)2017 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-29048346

RESUMO

The elastoplastic deformation behaviors of hollow glass microspheres/iron syntactic foam under tension were modeled using a representative volume element (RVE) approach. The three-dimensional microstructures of the iron syntactic foam with 5 wt % glass microspheres were reconstructed using the random sequential adsorption algorithm. The constitutive behavior of the elastoplasticity in the iron matrix and the elastic-brittle failure for the glass microsphere were simulated in the models. An appropriate RVE size was statistically determined by evaluating elastic modulus, Poisson's ratio, and yield strength in terms of model sizes and boundary conditions. The model was validated by the agreement with experimental findings. The tensile deformation mechanism of the syntactic foam considering the fracture of the microspheres was then investigated. In addition, the feasibility of introducing the interfacial deboning behavior to the proposed model was briefly investigated to improve the accuracy in depicting fracture behaviors of the syntactic foam. It is thought that the modeling techniques and the model itself have major potential for applications not only in the study of hollow glass microspheres/iron syntactic foams, but also for the design of composites with a high modulus matrix and high strength reinforcement.

15.
J Audiol Otol ; 21(3): 152-155, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28942633

RESUMO

Cochlear implant (CI) surgery in cholesteatoma is challenging because of the risk of residual or recurrent infection. Although CI could be done with subtotal petrosectomy in single or staged surgery, this surgery needed additional surgical procedures to obliterate the mastoid cavity. This paper describes a new surgical technique for CI surgery in cholesteatoma without external auditory canal closure.

16.
Eur Arch Otorhinolaryngol ; 274(1): 143-149, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27544193

RESUMO

The aim of this study was to assess the outcomes of various treatment modalities for profound idiopathic sudden sensorineural hearing loss (ISSNHL) and confirm the prognostic factors. In total, 191 patients were enrolled after a thorough medical chart review of patients diagnosed with unilateral, profound ISSNHL (≥90 dB). Epidemiological profiles, therapeutic regimens, and the results of pure tone audiometry tests were recorded for all patients. Final recovery was assessed according to Siegel's criteria and by comparing the final hearing level of the affected ear with that of the unaffected ear. The mean follow-up duration and the final hearing level were 75 ± 54 days and 77 ± 24 dB, respectively. None of the evaluated prognostic factors were significantly associated with complete recovery (<25 dB). However, improved hearing in both ears, the absence of dizziness, the use of lipo-prostaglandin E1 (lipo-PGE1), and the use of plasma volume expanders were independently associated with a final hearing level of up to 45 dB (p < 0.05). Steroid dose reduction, worse initial hearing, and non-use of lipo-PGE1 increased the possibility of no recovery. Although the efficacy of oral steroid treatment for profound ISSNHL has been questioned, steroid dose reduction was significantly associated with no recovery. Therefore, adequate oral corticosteroid doses should be considered in the absence of contraindications. In addition, the use of lipo-PGE1 and/or a plasma volume expander seems preferable for better recovery, and their use for the management of profound ISSNHL should be considered.


Assuntos
Perda Auditiva Neurossensorial/tratamento farmacológico , Perda Auditiva Súbita/tratamento farmacológico , Recuperação de Função Fisiológica , Alprostadil/uso terapêutico , Relação Dose-Resposta a Droga , Feminino , Glucocorticoides/administração & dosagem , Humanos , Modelos Logísticos , Masculino , Metilprednisolona/administração & dosagem , Pessoa de Meia-Idade , Substitutos do Plasma/uso terapêutico , Prognóstico , Estudos Retrospectivos , Vasodilatadores/uso terapêutico
17.
Laryngoscope ; 126(11): E379-E385, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27328420

RESUMO

OBJECTIVES/HYPOTHESIS: The purpose of this study was to investigate the effect of early postnatal neurotrophin-3 (NT3) support on hearing acquisition. STUDY DESIGN: A prospective experimental animal study. METHODS: Adenoviral (Ad) vectors expressing green fluorescence protein (GFP) alone or in combination with NT3 were injected into the scala tympani through the round window of 5-postnatal-day-old (P5) rats. Changes in NT3 mRNA level, hearing thresholds, and morphological studies were done after the viral vector injection. RESULTS: NT3 mRNA was significantly increased in the Ad-GFP-NT3 group compared to the normal-developmental group and Ad-GFP alone group. GFP was widely expressed in the cochlea such as in the hair cells, supporting cell area, and spiral ganglion neurons. Auditory brainstem response thresholds were significantly lower in the Ad-GFP-NT3 group compared to the normal-developmental group and Ad-GFP alone group at P15. CONCLUSIONS: These results show that early postnatal NT3 overexpression may accelerate the acquisition of hearing in rats. LEVEL OF EVIDENCE: NA Laryngoscope, 126:E379-E385, 2016.


Assuntos
Vetores Genéticos/administração & dosagem , Proteínas de Fluorescência Verde/administração & dosagem , Audição/genética , Neurotrofina 3/genética , RNA Mensageiro/metabolismo , Animais , Cóclea/crescimento & desenvolvimento , Potenciais Evocados Auditivos do Tronco Encefálico/genética , Técnicas de Transferência de Genes , Terapia Genética/métodos , Estudos Prospectivos , Ratos , Ratos Sprague-Dawley , Janela da Cóclea , Rampa do Tímpano
18.
Neural Plast ; 2016: 7287180, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26881130

RESUMO

Dizziness and vertigo frequently occur after cochlear implantation (CI) surgery, particularly during the early stages. It could recover over time but some of the patients suffered from delayed or sustained vestibular symptoms after CI. This study used rat animal models to investigate the effect of unilateral cochleostomy on the vestibular organs over time. Twenty-seven Sprague Dawley rats underwent cochleostomy to evaluate the postoperative changes in hearing threshold, gain and symmetry of the vestibular ocular response, overall balance function, number of hair cells in the crista, and the c-Fos activity in the brainstem vestibular nucleus. Loss of vestibular function was observed during the early stages, but function recovered partially over time. Histopathological findings demonstrated a mild decrease in vestibular hair cells numbers. Increased c-Fos immunoreactivity in the vestibular nucleus, observed in the early stages after cochleostomy, decreased over time. Cochleostomy is a risk factor for peripheral vestibular organ damage that can cause functional impairment in the peripheral vestibular organs. Altered vestibular nucleus activity may be associated with vestibular compensation and plasticity after unilateral cochleostomy.


Assuntos
Cóclea/cirurgia , Plasticidade Neuronal , Núcleos Vestibulares/fisiopatologia , Estimulação Acústica , Animais , Limiar Auditivo/fisiologia , Potenciais Evocados Auditivos do Tronco Encefálico , Células Ciliadas Vestibulares/patologia , Masculino , Proteínas Proto-Oncogênicas c-fos/metabolismo , Ratos , Ratos Sprague-Dawley , Teste de Desempenho do Rota-Rod , Núcleos Vestibulares/metabolismo
19.
Clin Exp Otorhinolaryngol ; 8(3): 218-23, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26330915

RESUMO

OBJECTIVES: The purpose of this study was to investigate the clinical features, radiologic findings, and treatment outcomes in patients of facial nerve paralysis with chronic ear infections. And we also aimed to evaluate for radiologic sensitivities on facial canal, labyrinth and cranial fossa dehiscences in middle ear cholesteatomas. METHODS: A total of 13 patients were enrolled in this study. Medical records were retrospectively reviewed for clinical features, radiologic findings, surgical findings, and recovery course. In addition, retrospective review of temporal bone computed tomography (CT) and operative records in 254 middle ear cholesteatoma patients were also performed. RESULTS: Of the 13 patients, eight had cholesteatomas in the middle ear, while two patients exhibited external auditory canal cholesteatomas. Chronic suppurative otitis media, petrous apex cholesteatoma and tuberculous otitis media were also observed in some patients. The prevalence of facial paralysis in middle ear cholesteatoma patients was 3.5%. The most common involved site of the facial nerve was the tympanic segment. Labyrinthine fistulas and destruction of cranial bases were more frequently observed in facial paralysis patients than nonfacial paralysis patients. The radiologic sensitivity for facial canal dehiscence was 91%. The surgical outcomes for facial paralysis were relatively satisfactory in all patients except in two patients who had petrous apex cholesteatoma and requiring conservative management. CONCLUSION: Facial paralyses associated with chronic ear infections were observed in more advanced lesions and the surgical outcomes for facial paralysis were relatively satisfactory. Facial canal dehiscences can be anticipated preoperatively with high resolution CTs.

20.
Vet Immunol Immunopathol ; 168(1-2): 118-30, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-26384699

RESUMO

Monoclonal antibodies (mAbs) specific for leukocyte differentiation molecules (LDMs) were developed during the past few decades to expand reagents for research in ruminants, pigs, and horses. The specificity of some of the mAb-defined molecules was determined through participation in international workshops. Other molecules identified with mAbs during this time, and more recently with mAbs developed after the workshops, have remained partially characterized. Efforts are now underway to characterize the specificity of these mAbs. As reported here, flow cytometry (FC) was used to screen two sets of hybridomas to determine how many of the hybridomas produce mAbs that detect molecules with up-regulated expression on activated lymphocytes or NK cells. Thirty four hybridomas were identified. Comparison of the patterns of reactivity of the mAbs showed some of the mAbs formed clusters that recognize 5 different molecules. FC showed one cluster recognized CD25. Use of mass spectrometry showed 4 clusters recognized orthologues of CD26, CD50, gp96 and signaling lymphocytic activation molecule family member 9 (SLAMF9). Verification and documentation that CD26, CD50, and SLAMF9 were only up-regulated on activated cells was obtained with PBMC from calves vaccinated with a Mycobacterium avium paratuberculosis mutant, Map-relA. CD26 and CD50 were up-regulated on NK cells, CD4 and CD8 T cells and γδ T cells. SLAMF9 was only up-regulated on CD4, CD8, and γδ T cells. gp96 was detected on granulocytes, monocytes and activated NK cells. Detection was attributable to the binding of gp96 to its receptor CD91.


Assuntos
Anticorpos Monoclonais/imunologia , Células Matadoras Naturais/imunologia , Subpopulações de Linfócitos T/imunologia , Animais , Especificidade de Anticorpos , Antígenos CD/metabolismo , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Bovinos , Dipeptidil Peptidase 4/metabolismo , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Células Matadoras Naturais/citologia , Ativação Linfocitária , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Receptores de Superfície Celular/metabolismo , Membro 1 da Família de Moléculas de Sinalização da Ativação Linfocitária , Subpopulações de Linfócitos T/citologia
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