Simultaneous Intracochlear Pressure Measurements from Two Cochlear Locations: Propagation of Distortion Products in Gerbil

Abstract

Sound energy propagates in the cochlea through a forward-traveling or slow wave supported by the cochlear partition and fluid inertia. Additionally, cochlear models support traveling wave propagation in the reverse direction as the expected mechanism for conveying otoacoustic emissions out of the cochlea. Recently, however, this hypothesis has been questioned, casting doubt on the process by which otoacoustic emissions travel back out through the cochlea. The proposed alternative reverse travel path for emissions is directly through the fluids of the cochlea as a compression pressure in the form of a fast wave. In the present study, a custom-made micro-pressure sensor was used in vivo in the gerbil cochlea to map two-tone-evoked pressure responses at distinct longitudinal and vertical locations in both the scala tympani and scala vestibuli. Analyses of the magnitude and phase of intracochlear pressure responses at the primary tone and distortion product frequencies were used to distinguish between fast and slow waves in both the forward- and reverse-propagation directions. Results demonstrated that distortion products may travel in both forward and reverse directions post-generation and the existence of both traveling and compression waves. The forward-traveling component appeared to duplicate the process of any external tone, tuned to the local characteristic-frequency place, as it increased compressively and nonlinearly with primary-tone levels. A compression wave was evidenced at frequencies above the cutoff of the recording site. In the opposite direction, a reverse-traveling wave played the major role in driving the stapes reversely and contributed to the distortion product otoacoustic emission. The compression wave may also play a role in reverse propagation when distortion products are generated at a region close to the stapes.

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Wartime toxin exposure: recognising the silent killer

Wartime toxin exposures have been implicated in the genesis of malignancy in war veterans. Agent Orange, one toxin among many, has been linked to malignancy and the subcomponent phenoxyacetic acid has been associated with soft tissue sarcomas (STSs). This case demonstrates the association between a wartime toxin exposure (Agent Orange) and subsequent cancer development. Ultimately, we aim to highlight the importance of simple, specific questions in the patient history to account for previous wartime toxin exposures.

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IL-9-producing cells in the development of IgE-mediated food allergy

Abstract

Food allergy is a harmful immune reaction driven by uncontrolled type 2 immune responses. Considerable evidence demonstrates the key roles of mast cells, IgE, and TH2 cytokines in mediating food allergy. However, this evidence provides limited insight into why only some, rather than all, food allergic individuals are prone to develop life-threatening anaphylaxis. Clinical observations suggest that patients sensitized to food through the skin early in life may later develop severe food allergies. Aberrant epidermal thymic stromal lymphopoietin and interleukin (IL) 33 production and genetic predisposition can initiate an allergic immune response mediated by dendritic cells and CD4⁺TH2 cells in inflamed skin. After allergic sensitization, intestinal IL-25 and food ingestion enhance concerted interactions between type 2 innate lymphoid cells (ILC2s) and CD4⁺TH2 cells, which perpetuate allergic reactions from the skin to the gut. IL-4 and cross-linking of antigen/IgE/FcεR complexes induce emigrated mast cell progenitors to develop into the multi-functional IL-9-producing mucosal mast cells, which produce prodigious amounts of IL-9 and mast cell mediators to drive intestinal mastocytosis in an autocrine loop. ILC2s and TH9 cells may also serve as alternative cellular sources of IL-9 to augment the amplification of intestinal mastocytosis, which is the key cellular checkpoint in developing systemic anaphylaxis. These findings provide a plausible view of how food allergy develops and progresses in a stepwise manner and that atopic signals, dietary allergen ingestion, and inflammatory cues are fundamental in promoting life-threatening anaphylaxis. This information will aid in improving diagnosis and developing more effective therapies for food allergy-triggered anaphylaxis.

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Aims & Scope/Editorial board

Publication date: January 2017
Source:Archives of Oral Biology, Volume 73





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Should all systematic reviews be at the top of the pyramid?

Publication date: January 2017
Source:Archives of Oral Biology, Volume 73
Author(s): Heitor Marques Honório




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Resistin as potential biomarker for chronic periodontitis: A systematic review and meta-analysis

Publication date: January 2017
Source:Archives of Oral Biology, Volume 73
Author(s): Zohaib Akram, Zubaidah Haji Abdul Rahim, Tara Bai Taiyeb-Ali, Mohd Shahril Amin Shahdan, Nor Adinar Baharuddin, Rathna Devi Vaithilingam, Syarida Hasnur Safii
ObjectivesTo determine the serum and gingival crevicular fluid (GCF) levels of resistin between individuals with chronic periodontitis (CP) and those without CP, and to evaluate the role of resistin in CP.Materials and methodsThe addressed focused question was "Is there a difference in the resistin levels between individuals with CP and those without CP?" four electronic databases: Medline, PubMed (National Institutes of Health, Bethesda), EMBASE, and Science direct databases from 1977 up to March 2016 for appropriate articles addressing the focused question. EMBASE and Medline were accessed using OVID interface which facilitated simultaneous search of text words, MeSH or Emtree. Unpublished studies (gray literature) were identified by searching the Open-GRAY database and references of the included studies (cross referencing) were performed to obtain new studies. In-vitro studies, animal studies, studies that reported levels of other cytokines but not resistin, letters to the editor and review papers were excluded.ResultsTen studies were included. Nine studies compared resistin levels between CP and periodontally healthy (H) individuals and reported higher mean serum and GCF levels of resistin in CP patients than the H controls. Two studies showed comparable resistin levels from GCF and serum between diabetes mellitus with CP (DMCP) and CP groups. Three studies included obese subjects and showed comparable serum and GCF resistin levels between obese subjects with CP (OBCP) and CP subjects.ConclusionsCP patients were presented with elevated levels of GCF or serum resistin as compared with H individuals. Resistin modulates inflammation in chronic periodontal disease and may be used as surrogate measure to identify subjects at risk for periodontitis. Resistin levels in patients with CP and systemic inflammatory disorders such as diabetes, obesity, or rheumatoid arthritis was not significantly higher than the levels in patients with only CP.



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Decreasing loco-regional recurrence for oral cavity cancer with total Mohs margins technique

Abstract

Background

The conventional technique for cancer resection margin analysis studies only 0.1% of the surgical margins. Complete frozen section margins - also known as Mohs margins – allows for analysis of 100% of the surgical margins.

Methods

The objective of our study is to compare oral cavity cancer loco-regional recurrence rates when treated by total frozen sections technique (Total Mohs margins) versus conventional margins. We conducted a multicenter retrospective cohort chart review. Loco-regional oral cancer recurrence rates were compared between patients treated with total Mohs margins (2007–2013) and patients treated with conventional margins techniques (2002–2007).

Results

After applying inclusion criteria, a total of 60 patients treated by total Mohs margins and 57 patients with conventional margins were identified. Patients had similar baseline cancer stages, pathological types, past head and neck cancers and comorbidities (all p > 0.05). One-year recurrence rate was lower (10.0% vs 21.1%, p = 0.019) in favor of Mohs total margins and stayed significantly lower at 5 years of follow-up. When adjusted for T grade with N0 disease, Mohs technique was still beneficial in loco-regional recurrence for Tis-T4N0 up to 2 years (10.5% vs 25.7%, z-score 1.849, p = 0.032). The Number Needed to Treat at 2 years of follow-up for this subgroup of patients (Tis-T4N0) is 6.6. Margins had to be retaken more often intra-operatively in Mohs technique (68.3% vs 12.3%, p < 0.0001), mainly for positive deep margins (48.6% of all margins, p = 0.028). Duration of surgery was not increased with Mohs vs conventional technique (380 min vs 475 min respectively, p = 0.025).

Conclusions

Mohs total margins may result in a significant reduction in cancer recurrence rate at 5 years compare to conventional surgery. Moreover, duration of surgery was not increased when using Mohs technique when judiciously performed.

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