The inner ear is located deep in the temporal bone and has a complex anatomy. It is difficult to observe and obtain pathological tissues directly. Therefore, the diagnosis and treatment of inner ear ...diseases have always been a major clinical problem. The onset of inner ear disease can be accompanied by symptoms such as hearing loss, dizziness and tinnitus, which seriously affect people's lives. Nanoparticles have the characteristics of small size, high bioavailability and strong plasticity. With the development of related research on nanoparticles in inner ear diseases, nanoparticles have gradually become a research hotspot in inner ear diseases. This review briefly summarizes the research progress, opportunities and challenges of the application of nanoparticles in inner ear diseases.
Hydroxylated isoprenoid glycerol dialkyl glycerol tetraethers (OH‐GDGTs) preserved in marine sediments are thought to be controlled by sea surface temperature (SST). However, water depth may also ...exert a significant influence on OH‐GDGTs. Here, we investigated sedimentary OH‐GDGTs in the Kermadec and Atacama trench regions (2,560–9,560 m water depth). Sedimentary OH‐GDGTs in hadal trenches were dominated by OH‐GDGT‐0 (72 ± 8%), potentially reflecting an adaption of source organisms to ambient cold deep water. This result, combined with global data set, revealed that the predominance of OH‐GDGT‐0 is a ubiquitous phenomenon in deep‐sea sediments, leading to a considerable underestimation of RI‐OH′‐derived SSTs. By considering both SST and water depth effects, we developed more accurate OH‐GDGT‐based paleothermometers for both shallow regions and the global ocean, encompassing the full‐ocean‐depth range. Our findings highlight the importance of accounting for the effect of water depth on OH‐GDGTs and provide improved tools for reconstructing paleo‐SSTs.
Plain Language Summary
Building quantitative proxies that can accurately estimate SSTs is one of the most common themes in paleoceanography. Archeal‐derived hydroxylated isoprenoid glycerol dialkyl glycerol tetraethers (OH‐GDGTs) preserved in marine sediments have a potential to reflect past sea surface temperatures (SSTs). However, the source organisms of OH‐GDGTs can live throughout the water column, implying that sedimentary OH‐GDGTs record an integrated water column signal rather than only SST. Currently, the effect of water depth on sedimentary OH‐GDGTs remains vague. We investigated the distribution of OH‐GDGTs in 13 sediment cores in the hadal zone, which represents the deepest and least explored habitats on Earth's surface. The data from this study and literature revealed that the deep‐sea (including hadal trench) sediments are characterized by a predominance of OH‐GDGT‐0, which causes a considerable underestimation of OH‐GDGT‐derived SSTs. We evaluated the effects of both SST and water depth on OH‐GDGTs and established new calibrations that more accurately reconstruct paleotemperatures at a global scale.
Key Points
Sedimentary hydroxylated isoprenoid glycerol dialkyl glycerol tetraethers (OH‐GDGTs) were first investigated in the Kermadec and Atacama trenches with water depth ranging from 2,560 to 9,560 m
Water depth has large impact on OH‐GDGT distributions with higher OH‐GDGT‐0% and lower RI‐OH′ values of deep‐sea sediments
More accurate global sea surface temperature calibrations based on OH‐GDGTs were established
To report outcomes of balloon dilation Eustachian tuboplasty combined with tympanostomy tube insertion and middle ear pressure equalization therapy in treatment of recurrent secretory otitis media.
...Fifty one patients with recurrent secretory otitis media (62 ears) underwent balloon dilation of Eustachian tube and tympanic tube insertion under general anesthesia, followed by long term middle ear pressure equalization therapies. The Eustachian tube score (ETS) and Eustachian tube function questionnaire (ETDQ-7) were used for pre- and postoperative (up to 12 months) evaluation of Eustachian tube functions.
The mean ETS score was 2.34 ± 0.97 preoperatively, and 6.17 ± 1.54, 7.23 ± 1.62, 8.24 ± 1.97, and 7.63 ± 1.86 at 1, 3, 6 and 12 months postoperatively, respectively (P < 0.05). The ETDQ-7 score was 4.82 ± 1.07 preoperatively, and 2.20 ± 0.54, 2.32 ± 0.68, 2.53 ± 0.79, and 2.67 ± 0.76 at 1, 3, 6 and 12 months postoperatively, respectively (P < 0.05).
Balloon dilation of Eustachian tube combined with tympanostomy and catheterization resulted in significant improvement of subjective symptoms and objective evaluation of Eustachian tube functions in most patients with recurrent secretory otitis media, as indicated by the ETS and ETDQ-7 scores, demonstrating high levels of efficacy and patient satisfaction.
Sensorineural hearing loss (SNHL) is a common otologic condition caused by damage to hair cells and spiral ganglion neurons that affects transmission pathways. Most of these cells cannot be ...regenerated, and there has been no breakthrough in regeneration techniques for inner ear cells. SNHL has a high incidence rate and can cause a variety of clinical symptoms, greatly impacting people's daily lives. With limited clinical treatments, the search for critical targets is urgent. Studies have shown that inflammation is prevalent in the pathogenesis of SNHL and plays a significant role in it. Inflammation is a normal body defense response, and a systemic anti‐inflammatory approach is undesirable. It is crucial for us to identify potential targets of inflammation in SNHL and take measures specifically targeting those targets with minimal systemic impact. This paper firstly describes the role of inflammation in various types of SNHL and then provides an overview of the interactions between inflammation and cochlear immunity, cochlear microcirculation, vascular spasm, and glutamate metabolism and finally comprehensively examines the feasibility of targets in these interactions. This paper is expected to facilitate the development of targeted anti‐inflammation for SNHL and provide strategies and approaches for treating clinical SNHL.
This paper describes the role of inflammation in sensorineural hearing loss (SNHL). Inflammation affects SNHL primarily via cochlear immunity, microcirculation, vasospasm, and glutamate metabolism, often accompanied by immune cell infiltration, altered blood flow, ischemic damage, and synaptic injury. A comprehensive anti‐inflammatory approach is undesirable, and studying inflammation‐related mechanisms will aid the search for potential targets in SNHL.
A total of 43 seafloor surface sediment samples collected from the offshore region surrounding the Leizhou Peninsula were analyzed in terms of the total organic carbon content (TOC), total nitrogen ...(TN), organic carbon isotope (δ
13
C
org
) and sediment grain size. Our results showed that the organic carbon content in the samples ranged from 0.12 to 0.79%, with an average of 0.42% which was lower compared with other offshore regions of China, whereas the δ
13
C
org
was in the range of −22.47‰ to −19.18‰. The total nitrogen content ranged from 0.011 to 0.100% which was also low. The combination of δ
13
C
org
and TOC/TN ratio (5.1–14.3) suggested that the organic matter is dominant by marine authigenic source input, as marine sourced organic matter accounts for 71%, 82%, and 75% in the sediments from the offshore areas of the east side, west side and the south (Qiongzhou Strait) of the Leizhou Peninsula, respectively. The weak/poor correlations between the organic carbon and clay, silt content, the pH and Eh value suggested that organic matter abundance and distribution were influenced by the source input of organic matter, the seafloor sediments’ redox status, and seawater’s hydrodynamic condition.
The offshore of Leizhou Peninsula (LP, China), which contains unique ecosystems such as mangroves, seagrass beds, and coral reefs, is an environmentally sensitive area. For this reason, the levels of ...aliphatic hydrocarbon including biomarkers (hopanes, steranes) in the offshore seafloor sediments were analyzed in terms of their composition, distribution, and input sources and aimed to evaluate the extent of possible petroleum hydrocarbon contamination in the sediments of coastal areas. The total aliphatic hydrocarbons (TAH) fraction, the content of total
-alkanes (
C
-
C
) (∑
-alkanes), and content of hopane + sterane are in the range of 13.76-99.53, 1.22-8.33, and 0.02-0.23 μg/g dw, respectively. The presence of unresolved complex mixture (UCM) hydrocarbons hump and petrogenic steranes and hopanes in these seafloor sediments suggest that petrogenic sourced hydrocarbon inputs were present. The stations on the peninsula's southwest side had the lowest values of UCM/resolved aliphatic compounds (UCM/R) and UCM/
-alkanes. These findings suggest that seafloor sediments from the southwest offshore of the peninsula were likely contaminated by recently inputted petroleum hydrocarbons. The presence of relatively high ∑
-alkanes content in seafloor sediments from southwest offshore of the LP, combined with relatively low natural
-alkane ratios (NARs), indicates an increased influence of petrogenic hydrocarbons. The elevated levels of recent petrogenic hydrocarbon contamination in the sediments from the LP's southwestern offshore were likely related to petroleum exploitation in the Beibu Gulf's Maichen and Wushi sags.
Here, we developed a safe and highly effective nanocarrier using β-cyclodextrin (β-CD) and oligoarginine peptide (Arg8)-modified dendrimer-entrapped gold nanoparticles (Au@CD-PAMAM-Arg8), with a ...diameter of 5 nm, for improved delivery of dexamethasone (Dex) to the inner ear. The properties and
distribution of the Au@CD-PAMAM-Arg8 were assessed
, and a streptomycin (SM) ototoxicity model was used
. Flow cytometry analysis of HEIOC1 cells treated with Au@CD-PAMAM-Arg8 and Au @CD-PAMAM at different time intervals indicated that cell uptake efficiency of the drug delivery carrier Au@CD-PAMAM-Arg8 was higher than that of Au @CD-PAMAM. Au@CD-PAMAM-Arg8 carrying Dex (Au@CD-PAMAM-Arg8/Dex) were mainly distributed in hair cells, the spiral ganglion, lateral wall, and nerve fibers and had stronger protective effects on the inner ear than Dex administration alone.
tracer tests revealed that tympanic injection was significantly more effective than posterior ear injection, muscle injection, and tail vein injection, whereas clinical retro-auricular injection could not increase the efficiency of drug delivery into the ear. Electrocochleography results showed that Au@CD-PAMAM-Arg8/Dex significantly improved hearing in C57/BL6 mice after SM exposure. These findings indicate that Au@CD-PAMAM-Arg8 may be the useful drug carriers for the treatment of inner ear diseases.
Evidence suggests that glucocorticoids are important in the treatment of sudden hearing loss (SHL) and Meniere’s disease (MD). However, different glucocorticoid administration methods may have a ...significant impact on treatment outcomes.
This study aimed to investigate effects of different glucocorticoid administration methods on sudden hearing loss and Meniere’s disease.
In this study, glucocorticoids were administered orally in 18 patients, by retroauricular injection in 15 patients and by intratympanic injection in 15 patients. White blood cell (WBC) count, serum K+, fasting plasma glucose (FPG), body temperature, heart rate and blood pressure were used to evaluate effects of glucocorticoids on patients with hearing loss. Visual analog scale (VAS) of pain and sleep disorders were also surveyed, and pure tone audiometry (PTA) results were compared among groups to evaluate efficacy of different glucocorticoids administration methods.
WBC count, heart rate and blood pressure were higher in patients taking oral glucocorticoids, while body temperature, serum K+ and FPG levels did not change in all three groups. However, patients who received intratympanic injection of glucocorticoids experienced more pain, while those taking oral glucocorticoids reported more sleep impairment. Treatment efficacy on hearing loss was not significantly different among the three groups.
These findings suggest that systemic glucocorticoid administration can result in greater whole body responses than local administration, but with similar hearing treatment efficacy.
Total organic carbon (TOC), total nitrogen (TN) and multi-biomarker indexes were analyzed for two sediment cores from the eastern coastal area of the Beibu Gulf (core 45, AMS
14
C dated) and ...Qiongzhou Strait (core 29), South China Sea. The results showed that the TOC and TN content of the samples studied were 0.32–0.62% and 0.02–0.07%, respectively. The hydrocarbons in offshore sediments of Leizhou Peninsula were consisted of biogenic hydrocarbons and petrogenic hydrocarbons. The Core 29 sediments contain more terrigenous organic matter than that of sediments in core 45 due to the difference in hydrodynamic conditions. The composition and distribution of various lipid biomarkers indicate the presence of petrogenic hydrocarbons in the sediments of the whole profile of two sediment cores. There are multiple natural sources of hydrocarbons that could potentially contribute to the petroleum background through oil seeps and erosion of carbon-rich rock outcrops or bitumen deposits. Deep sourced hydrocarbon inputs from the submarine hydrocarbon seepage cannot be excluded. Further study is needed to resolve the specific sources for the petrogenic hydrocarbons and may be significant to petroleum exploration in the study area.
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