Middle Ear Ossicular Joint Changes in Type 2 Diabetes Mellitus: A Histopathological Study.

OBJECTIVES: Although previous research has indicated inner ear changes in diabetes mellitus (DM) patients, no prior study has explored the middle ear, particularly the ossicles and their joints, in DM patients. This study aimed to investigate whether type 2 DM is associated with middle ear changes, specifically affecting the ossicular chain and joints. METHODS: This study included 47 ears from 25 patients with DM (male = 13, female = 12, age: 51.0 ± 20.5) and age- and sex-matched controls (male = 10, female = 10, age: 54.8 ± 15.9) (sex; p = 1.000, Age; p = 0.991). Otopathological evaluations of the auditory ossicles and incudomalleolar joint (IMJ) were performed using light microscopy. RESULTS: In the IMJ of DM cases, malleus hyalinized cartilage (Malleus hC) and incus hyalinized cartilage (Incus hC) were significantly increased compared with control cases (Malleus hC; DM, 34.17 ± 9.71 µm vs. control 21.96 ± 4.16 µm, p < 0.001) (Incus hC; DM 35.11 ± 10.12 µm vs. control 22.42 ± 4.368 µm, p < 0.001). In addition, bone-line distance was significantly longer than in DM cases than control cases (DM 266.72 ± 59.11 µm vs. control 239.81 ± 35.56 µm p = 0.040). On the other hand, joint discus distance was longer in the control group than in DM cases (DM 96.84 ± 36.80 µm vs. Control 113.63 ± 23.81 µm, p = 0.001). CONCLUSIONS: This study reveals a notable increase in the hyalinized cartilage layer and bone-line distance accompanied by reducing joint discus distance within the IMJ in DM cases. These findings suggest that DM may influence microjoints, such as the IMJ, and potentially impact auditory function. EVIDENCE LEVEL: N/A Laryngoscope, 134:2871-2878, 2024.

Acute and chronic stress alter behavioral laterality in dogs.

Dogs are one of the key animal species in investigating the biological mechanisms of behavioral laterality. Cerebral asymmetries are assumed to be influenced by stress, but this subject has not yet been studied in dogs. This study aims to investigate the effect of stress on laterality in dogs by using two different motor laterality tests: the Kong™ Test and a Food-Reaching Test (FRT). Motor laterality of chronically stressed (n = 28) and emotionally/physically healthy dogs (n = 32) were determined in two different environments, i.e., a home environment and a stressful open field test (OFT) environment. Physiological parameters including salivary cortisol, respiratory rate, and heart rate were measured for each dog, under both conditions. Cortisol results showed that acute stress induction by OFT was successful. A shift towards ambilaterality was detected in dogs after acute stress. Results also showed a significantly lower absolute laterality index in the chronically stressed dogs. Moreover, the direction of the first paw used in FRT was a good predictor of the general paw preference of an animal. Overall, these results provide evidence that both acute and chronic stress exposure can change behavioral asymmetries in dogs.

Three-Dimensional Analysis of Round Window Membrane in the Chinchilla Model with Acute Otitis Media Induced with Streptococcus Pneumoniae 7F.

OBJECTIVE: The purpose of this study was to investigate the morphological changes of round window membrane (RWM) in chinchillas with Streptococcus pneumoniae (S. pneumoniae) serotype 7F induced acute otitis media (AOM) by two dimensional (2D) and three dimensional (3D) measurements. METHODS: Temporal bone specimens taken from 12 chinchillas were divided into two groups. The control group consisted of healthy animals that were injected with intrabullar saline. The subjects in the experimental group were induced with AOM by intrabullar injection of S. pneumoniae 7F. The 2D and 3D measurements of RWM were compared between the groups. RESULTS: Dramatic changes were noted in the RWM of the experimental group compared to the control group. The thickness [mean ± standard deviation (SD)] of the RWM was significantly (p<0.05) increased in the experimental group compared to the control group by 2D measurements taken at three different points of RWM. Moreover, 3D measurements revealed that the volume (mean ± SD) of RWM was significantly (p=0.009) increased in the experimental group. CONCLUSION: The results of our study, which indicated significant change in RWM in both 2D and 3D measurements, may shed light on the relationship between AOM and inner ear diseases. Based on our results, we recommend evaluating 3D analyses of RWM, which provide useful data, to better understand the changes in the membrane.