Calculation of energy exchange between the outer hair cell and structural components of the organ of Corti, using the in vivo measurement data

2015 ◽  
Vol 138 (3) ◽  
pp. 1942-1942
Author(s):  
Amir Nankali ◽  
Karl Grosh
Keyword(s):  
Hair Cell ◽  
Energy Exchange ◽  
Outer Hair Cell ◽  
Measurement Data ◽  
Organ Of Corti ◽  
Structural Components ◽  
In Vivo Measurement

scholarly journals Outer Hair Cell Somatic Electromotility In Vivo and Power Transfer to the Organ of Corti

2012 ◽  
Vol 102 (3) ◽  
pp. 388-398 ◽  
Author(s):  
Sripriya Ramamoorthy ◽  
Alfred L. Nuttall
Keyword(s):  
Hair Cell ◽  
Outer Hair Cell ◽  
Organ Of Corti ◽  
Power Transfer

scholarly journals Watching Death in the Gerbil Cochlea Using Optical Coherence Tomography (OCT)

2021 ◽  
Author(s):  
Nam Hyun Cho ◽  
Haobing Wang ◽  
Sunil Puria
Keyword(s):  
Optical Coherence Tomography ◽  
Hair Cell ◽  
Outer Hair Cell ◽  
Round Window ◽  
Fluid Pressure ◽  
Organ Of Corti ◽  
Round Window Membrane ◽  
Tectorial Membrane ◽  
Optical Coherence

Because it is difficult to directly observe the morphology of the living cochlea, our ability to infer the mechanical functioning of the living ear has been limited. Nearly all of our knowledge about cochlear morphology comes from postmortem tissue that was fixed and processed using procedures that possibly distort the structures and fluid spaces of the organ of Corti. In this study, optical coherence tomography was employed to obtain in vivo and postmortem micron-scale volumetric images of the high-frequency hook region of the gerbil cochlea through the round-window membrane. The anatomical structures and fluid spaces of the organ of Corti were segmented and quantified in vivo and over a 90-minute postmortem period. The results show that some aspects of the organ of Corti are significantly altered over the course of death, such as the volumes of the fluid spaces, whereas the dimensions of other features change very little. We postulate that the fluid space of the outer tunnel and its surrounding tectal cells form a resonant structure that can affect the motion of the reticular lamina and thereby have a profound effect on outer-hair-cell transduction and thus cochlear amplification. In addition, the in vivo fluid pressure of the inner spiral sulcus is postulated to effectively inflate the connected sub-tectorial gap between the tectorial membrane and the reticular lamina. This gap height decreases after death, which is hypothesized to reduce and disrupt hair-cell transduction.

scholarly journals Towards planning of osteotomy around the knee with quantitative inclusion of the adduction moment: a biomechanical approach

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Margit Biehl ◽  
Philipp Damm ◽  
Adam Trepczynski ◽  
Stefan Preiss ◽  
Gian Max Salzmann
Keyword(s):  
Gait Analysis ◽  
Measurement Data ◽  
Frontal Plane ◽  
Medial Compartment ◽  
Knee Adduction Moment ◽  
In Vivo Measurement ◽  
Force Ratio ◽  
Leg Alignment ◽  
Alignment Angle

Abstract Purpose Despite practised for decades, the planning of osteotomy around the knee, commonly using the Mikulicz-Line, is only empirically based, clinical outcome inconsistent and the target angle still controversial. A better target than the angle of frontal-plane static leg alignment might be the external frontal-plane lever arm (EFL) of the knee adduction moment. Hypothetically assessable from frontal-plane-radiograph skeleton dimensions, it might depend on the leg-alignment angle, the hip-centre-to-hip-centre distance, the femur- and tibia-length. Methods The target EFL to achieve a medial compartment force ratio of 50% during level-walking was identified by relating in-vivo-measurement data of knee-internal loads from nine subjects with instrumented prostheses to the same subjects’ EFLs computed from frontal-plane skeleton dimensions. Adduction moments derived from these calculated EFLs were compared to the subjects’ adduction moments measured during gait analysis. Results Highly significant relationships (0.88 ≤ R2 ≤ 0.90) were found for both the peak adduction moment measured during gait analysis and the medial compartment force ratio measured in vivo to EFL calculated from frontal-plane skeleton dimensions. Both correlations exceed the respective correlations with the leg alignment angle, EFL even predicts the adduction moment’s first peak. The guideline EFL for planning osteotomy was identified to 0.349 times the epicondyle distance, hence deducing formulas for individualized target angles and Mikulicz-Line positions based on full-leg radiograph skeleton dimensions. Applied to realistic skeleton geometries, widespread results explain the inconsistency regarding correction recommendations, whereas results for average geometries exactly meet the most-consented “Fujisawa-Point”. Conclusion Osteotomy outcome might be improved by planning re-alignment based on the provided formulas exploiting full-leg-radiograph skeleton dimensions.

scholarly journals In Vivo Outer Hair Cell Length Changes Expose the Active Process in the Cochlea

PLoS ONE ◽  
2012 ◽  
Vol 7 (4) ◽  
pp. e32757 ◽  
Author(s):  
Dingjun Zha ◽  
Fangyi Chen ◽  
Sripriya Ramamoorthy ◽  
Anders Fridberger ◽  
Niloy Choudhury ◽  
...  
Keyword(s):  
Hair Cell ◽  
Outer Hair Cell ◽  
Cell Length ◽  
Active Process ◽  
Length Changes

scholarly journals Toll-like receptor 4 is activated by platinum and contributes to cisplatin-induced ototoxicity

2020 ◽  
Author(s):  
Ghazal Babolmorad ◽  
Asna Latif ◽  
Niall M. Pollock ◽  
Ivan K. Domingo ◽  
Cole Delyea ◽  
...  
Keyword(s):  
Transition Metals ◽  
Hair Cell ◽  
Childhood Cancer ◽  
Small Molecule ◽  
Therapeutic Target ◽  
Outer Hair Cell ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4

AbstractToll-like receptor 4 (TLR4) is famous for recognizing the bacterial endotoxin lipopolysaccharide (LPS) as its canonical ligand. TLR4 is also activated by other classes of agonist including some Group 9/10 transition metals. Roles for these non-canonical ligands in pathobiology mostly remain obscure, though TLR4 interactions with metals can mediate immune hypersensitivity reactions. In this work, we tested whether TLR4 can be activated by the Group 10 transition metal, platinum. We demonstrated that in the presence of TLR4, platinum activates pathways downstream of TLR4 to a similar extent as the known TLR4 agonists LPS and nickel. Platinum is the active moiety in cisplatin, a very potent and invaluable chemotherapeutic used to treat solid tumors in childhood cancer patients. Unfortunately, cisplatin use is limited due to an adverse effect of permanent hearing loss (cisplatin-induced ototoxicity, CIO). Herein, we demonstrated that cisplatin also activates TLR4, prompting the hypothesis that TLR4 mediates aspects of CIO. Cisplatin activation of TLR4 was independent of the TLR4 co-receptors CD14 and MD-2, which is consistent with TLR4 signaling elicited by transition metals. We found that TLR4 is required for cisplatin-induced inflammatory, oxidative and apoptotic responses in an ear outer hair cell line and for hair cell damage in vivo. Thus, TLR4 is a promising therapeutic target to mitigate CIO. We additionally identify a TLR4 small molecule inhibitor able to curtail cisplatin toxicity in vitro. Further work is warranted towards inhibiting TLR4 as a route to mitigating this adverse outcome of childhood cancer treatment.Significance StatementThis work identifies platinum, and its derivative cisplatin, as new agonists for TLR4. TLR4 contributes to cisplatin-induced hair cell death in vitro and in vivo. Genetic and small molecule inhibition of TLR4 identify this receptor as a druggable therapeutic target with promise to curtail cisplatin-induced ototoxicity, a devastating side-effect of an otherwise invaluable chemotherapeutic tool.

Outer Hair Cell Electromotility in vivo

2011 ◽  
Author(s):  
Sripriya Ramamoorthy ◽  
Alfred L. Nuttall ◽  
Christopher A. Shera ◽  
Elizabeth S. Olson
Keyword(s):  
Hair Cell ◽  
Outer Hair Cell

In vivo measurement of amplifying motion within the organ of Corti under sound stimulation using optical coherence tomography

2012 ◽  
Author(s):  
Niloy Choudhury ◽  
Fangyi Chen ◽  
Dingjun Zha ◽  
Anders Fridberger ◽  
Jiefu Zheng ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Organ Of Corti ◽  
Optical Coherence ◽  
Sound Stimulation ◽  
In Vivo Measurement
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