262 research outputs found
A Human-Derived Monoclonal Antibody Targeting Extracellular Connexin Domain Selectively Modulates Hemichannel Function
Connexin hemichannels, which are plasma membrane hexameric channels (connexons) composed of connexin protein protomers, have been implicated in a host of physiological processes and pathological conditions. A number of single point pathological mutations impart a "leaky" character to the affected hemichannels, i.e., make them more active or hyperactive, suggesting that normal physiological condition could be recovered using selective hemichannel inhibitors. Recently, a human-derived monoclonal antibody named abEC1.1 has been shown to inhibit both wild type and hyperactive hemichannels composed of human (h) connexin 26 (hCx26) subunits. The aims of this work were (1) to characterize further the ability of abEC1.1 to selectively modulate connexin hemichannel function and (2) to assess its in vitro stability in view of future translational applications. In silico analysis of abEC1.1 interaction with the hCx26 hemichannel identified critically important extracellular domain amino acids that are conserved in connexin 30 (hCx30) and connexin 32 (hCx32). Patch clamp experiments performed in HeLa DH cells confirmed the inhibition efficiency of abEC1.1 was comparable for hCx26, hCx30 and hCx32 hemichannels. Of note, even a single amino acid difference in the putative binding region reduced drastically the inhibitory effects of the antibody on all the other tested hemichannels, namely hCx30.2/31.3, hCx30.3, hCx31, hCx31.1, hCx37, hCx43 and hCx45. Plasma membrane channels composed of pannexin 1 were not affected by abEC1.1. Finally, size exclusion chromatography assays showed the antibody does not aggregate appreciably in vitro. Altogether, these results indicate abEC1.1 is a promising tool for further translational studies
Epidermal growth factor receptor expression in primary laryngeal cancer: An independent prognostic factor of neck node relapse
Pioglitazone Represents an Effective Therapeutic Target in Preventing Oxidative/Inflammatory Cochlear Damage Induced by Noise Exposure
Recent progress in hearing loss research has provided strong evidence for the imbalance of cellular redox status and inflammation as common predominant mechanisms of damage affecting the organ of Corti including noise induced hearing loss. The discovery of a protective molecule acting on both mechanisms is challenging. The thiazolidinediones, a class of antidiabetic drugs including pioglitazone and rosiglitazone, have demonstrated diverse pleiotrophic effects in many tissues where they exhibit anti-inflammatory, anti-proliferative, tissue protective effects and regulators of redox balance acting as agonist of peroxisome proliferator-activated receptors (PPARs). They are members of the family of ligand regulated nuclear hormone receptors that are also expressed in several cochlear cell types, including the outer hair cells. In this study, we investigated the protective capacity of pioglitazone in a model of noise-induced hearing loss in Wistar rats and the molecular mechanisms underlying this protective effects. Specifically, we employed a formulation of pioglitazone in a biocompatible thermogel providing rapid, uniform and sustained inner ear drug delivery via transtympanic injection. Following noise exposure (120 dB, 10 kHz, 1 h), different time schedules of treatment were employed: we explored the efficacy of pioglitazone given immediately (1 h) or at delayed time points (24 and 48 h) after noise exposure and the time course and extent of hearing recovery were assessed. We found that pioglitazone was able to protect auditory function at the mid-high frequencies and to limit cell death in the cochlear basal/middle turn, damaged by noise exposure. Immunofluorescence and western blot analysis provided evidence that pioglitazone mediates both anti-inflammatory and anti-oxidant effects by decreasing NF-κB and IL-1β expression in the cochlea and opposing the oxidative damage induced by noise insult. These results suggest that intratympanic pioglitazone can be considered a valid therapeutic strategy for attenuating noise-induced hearing loss and cochlear damage, reducing inflammatory signaling and restoring cochlear redox balance
A case-control study on the combined effects of p53 and p73 polymorphisms on head and neck cancer risk in an Italian population
<p>Abstract</p> <p>Background</p> <p>The purpose of this study is to analyze the combined effects of selected <it>p</it>53 and <it>p</it>73 polymorphisms and their interaction with lifestyle habits on squamous cell carcinoma of the head and neck (SCCHN) risk and progression in an Italian population.</p> <p>Methods</p> <p>Two hundred and eighty-three cases and 295 hospital controls were genotyped for <it>p</it>53 polymorphisms on exon 4 (Arg72Pro), intron 3 and 6, and <it>p</it>73 G4C14-to-A4T14. Their association with SCCHN was estimated using a logistic regression analysis, while a multinomial logistic regression approach was applied to calculate the effect of the selected polymorphisms on SCCHN different sites (oral cavity, oropharynx, hypopharynx and larynx). We performed an haplotype analysis of the <it>p</it>53 polymorphisms, and a gene-gene interaction analysis for the combined effects of <it>p</it>73 G4C14-to-A4T14 and <it>p</it>53 polymorphisms.</p> <p>Results</p> <p>We found a significant increased risk of SCCHN among individuals with combined <it>p</it>73 exon 2 G4A and <it>p</it>53 intron 3 variant alleles (OR = 2.22, 95% CI: 1.08–4.56), and a protective effect for those carrying the <it>p</it>53 exon 4-<it>p</it>53 intron 6 diplotype combination (OR = 0.67; 95% CI: 0.47–0.92). From the gene-environment interaction analysis we found that individuals aged < 45 years carrying <it>p</it>73 exon 2 G4A variant allele have a 12.85-increased risk of SCCHN (95% CI: 2.10–78.74) compared with persons of the same age with the homozygous wild type genotype. Improved survival rate was observed among <it>p</it>53 intron 6 variant allele carriers (Hazard Ratio = 0.51 (95% CI: 0.23–1.16).</p> <p>Conclusion</p> <p>Our study provides for the first time evidence that individuals carrying <it>p</it>53 exon 4 and <it>p</it>53 intron 6 variant alleles are significantly protected against SCCHN, and also shows that an additional risk is conferred by the combination of <it>p</it>73 exon 2 G4C14-to-A4T14 and <it>p</it>53 intron 3 variant allele. Larger studies are required to confirm these findings.</p
Patients' experiences with HMEs and attachments after total laryngectomy
OBJECTIVES: The short-term and long-term beneficial effects of HME use by laryngectomees are well described in literature. In this study, we document how laryngectomised patients, who previously did not use an HME, get accustomed to the use of HME and attachments. PARTICIPANTS: Thirty patients, who were at least 3 months post-laryngectomy and previously did not use an HME, were followed for 12 weeks and were asked to complete questionnaires about their experiences with the HME and attachments. RESULTS: Results show that when patients start using an HME, they report some difficulties with breathing resistance during the first 2 weeks of use. However, after 6 weeks, they have become accustomed to the breathing resistance and after 12 weeks over 96% reports that breathing was equal or less strenuous compared with breathing though an open stoma. Only a small proportion of patients experienced problems with increased coughing when starting HME use. CONCLUSIONS: This study provides insight in the way laryngectomised patients are experiencing the use of HMEs in the first weeks. These outcomes can contribute to a better knowledge of HME use by healthcare providers and help them to manage patient expectations and improving support to patients in achieving compliant HME use
Role of Narrow Band Imaging Technology in the Diagnosis and Follow up of Laryngeal Lesions: Assessment of Diagnostic Accuracy and Reliability in a Large Patient Cohort
BACKGROUND: The aim of this study was to assess diagnostic accuracy and reliability of narrow band imaging (NBI) in the differential diagnosis of laryngeal premalignant lesion, early cancers and recurrences.MATERIAL AND METHODS: We enrolled 231 patients who underwent endoscopic examination with white light endoscopy (WLE) + NBI and divided them into two groups, group A, without previous radiochemotherapy and group B, with previous radiochemotherapy. When indicated, we performed surgical biopsies to evaluate sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy and likelihood of endoscopic examination comparing WLE alone and WLE + NBI.RESULTS: A positive NBI lesion, compared with a negative NBI lesion, had a 29.68 (group A) and 13.96 (group B) times higher probability to be histologically positive (i.e., confirmed) compared with WLE alone improving the diagnostic accuracy. In group A, the NBI mode showed excellent sensitivity (95.0%), which was higher than WLE 2 mode (77.5%). However, the greatest differences were recorded regarding specificity (96.8% vs. 40.6%). In group B, both NBI alone and WLE + NBI mode showed a 94.1% specificity compared with WLE alone, which had a maximum specificity of 85.3%. The mode comparison between NBI and WLE in both groups showed a statistically significant difference, with p-values <0.0001.CONCLUSIONS: NBI represents a reliable technology in challenging situations, especially in the context of post-radiotherapy or post-surgical mucosal changes showing a high NPV. NBI could reduce the number of unnecessary biopsies related to increased microvascular anomaly revelation, which could help to identify early-stage lesions suitable for minimally invasive surgery and, consequently, decrease hospital admissions
LACK OF AN ASSOCIATION BETWEEN INHERITED THROMBOPHILIC RISK FACTORS AND IDIOPATIC SUDDEN SENSORINEURAL HEARING LOSS IN ITALIAN PATIENTS
Objectives: We investigated the presence of congenital thrombophilic risk factors in a population of consecutive Italian patients affected by idiopathic sudden sensorineural hearing loss (SSNHL).
Methods: We investigated 48 patients with idiopathic SSNHL for the presence of congenital thrombophilic risk factors. The factor V Leiden G1691A, the prothrombin G20210A allele, and methylenetetrahydrofolate reductase (MTHFR) C677T genotypes were investigated. Allele frequencies and genotype distribution of all factors found in patients were compared to those of 48 healthy subjects of the same ethnic background by Chi2 and odds-ratio analysis. Odds ratios and 95% confidence intervals were calculated for allele and genotype frequencies of all thrombophilia variants. Statistical significance was accepted with a p value of less than .05. We also performed the following blood tests: hemacytometric analysis including platelet count, prothrombin time, activated partial thromboplastin time, fibrinogen, erythrocyte sedimentation rate, C-reactive protein, protein S, protein C, antithrombin III, and activated protein C resistance.
Results: In our series, we did not find an association between SSNHL and abnormal levels of antithrombin III, protein C, protein S, D-dimer, or fibrinogen; activated protein C resistance; or factor V G1691A, prothrombin G20210A, or MTHFR C677T mutations.
Conclusions: At present, the few studies regarding genetic polymorphisms of congenital thrombophilic factors in SSNHL are not conclusive. According to our data, factor V G1691A, prothrombin G20210A, and MTHFR C677T variants should be not considered risk factors for SSNHL. Further large prospective studies are needed to provide currently lacking information and to improve our knowledge in the field before we recommend the determination of genetic polymorphism in SSNHL as routine practice
Coenzyme Q 10 and Cardiovascular Risk Factors in Idiopathic Sudden Sensorineural Hearing Loss Patients.
OBJECTIVES:: We investigated the association of idiopathic sudden sensorineural hearing loss (ISSNHL) with coenzyme Q (CoQ) and cardiovascular risk factors. STUDY DESIGN:: A prospective study. SETTING:: Hospital center. PATIENTS:: Thirty Italian patients with ISSNHL and 60 healthy Italian subjects. INTERVENTION:: Diagnostic. MAIN OUTCOME MEASURE:: Evaluation of serum CoQ levels and cardiovascular risk factors (total cholesterol, low-density lipoprotein [LDL], homocysteine [HCY]). The results were compared with variance analysis and Student's t test. Univariate and multivariate analysis were used to evaluate the association between ISSNHL and CoQ, total cholesterol, LDL, and HCY levels. RESULTS:: In our series, we found a significant association between ISSNHL and high total cholesterol (p < 0.05), high LDL (p = 0.021), and low CoQ (p < 0.05) levels. We did not find a significant association between ISSNHL and HCY levels. In the univariate analysis, low levels of CoQ, high levels of total cholesterol, and LDL were found to be significantly associated with ISSNHL. In the multivariate analysis, only high levels of total cholesterol and low levels of CoQ remained significantly associated with a high risk of sudden sensorineural hearing loss. CONCLUSION:: The studies regarding the role of cardiovascular risk factors in ISSNHL are not conclusive. This is the first report regarding the association of ISSNHL and low serum levels of the antioxidant CoQ. Further studies are needed toinvestigate the role of antioxidants, including CoQ, in ISSNHL
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