Vibroacoustic Response of the Tympanic Membrane to Hyoid-Borne Sound Generated during Echolocation in Bats.

The hyoid apparatus in laryngeally echolocating bats is unique as it forms a mechanical connection between the larynx and auditory bullae, which has been hypothesized to transfer the outgoing echolocation call to the middle ear during call emission. Previous finite element modeling (FEM) found that hyoid-borne sound can reach the bulla at an amplitude likely heard by echolocating bats; however, that study did not model how or if the signal could reach the inner ear (or cochlea). One route that sound could take is via stimulation of the eardrum-similarly to that of air-conducted sound. We used micro computed tomography (µCT) data to build models of the hyoid apparatus and middle ear from six species of bats with variable morphology. Using FEM, we ran harmonic response analyses to measure the vibroacoustic response of the tympanic membrane due to hyoid-borne sound generated during echolocation and found that hyoid-borne sound in all six species stimulated the eardrum within a range likely heard by bats. Although there was variation in the efficiency between models, there are no obvious morphological patterns to account for it. This suggests that hyoid morphology in laryngeal echolocators is likely driven by other associated functions.

Cytokine tear film profile determination in eyes of healthy dogs and those with inflammatory periocular and skin disorders.

Alterations in serum cytokine levels and profiles have been reported in association with a variety of disease conditions (e.g., allergic, immune-mediated, etc.) in both humans and animals. In comparison to serum cytokine measurements, tear cytokine measurements might be expected to more accurately reflect the inflammatory milieu associated with periocular disease. The purpose of this study was to use a multiplexed assay to compare the cytokine profile of tears in healthy dogs to those with inflammatory skin and periocular disease. We were able to detect IL-2, IL-6, IL-8, and TNF-α in >47 % of tear samples from both healthy canine patients and those with inflammatory dermatologic disease (with or without concurrent periocular involvement). In contrast, IL-7, IL-10 and IFN-γ were rarely detected. Dogs with both dermatologic and periocular disease (but not dermatologic disease alone) had higher levels of IL-8 (P < 0.001, P > 0.05, respectively) relative to healthy dogs. Patients with concurrent dermatologic and periocular disease also demonstrated significantly greater variability in IL-8 concentrations between eyes than did healthy dogs (P < 0.0001). Our findings suggest that tear cytokine analysis may prove to be a useful tool to investigate the role and interactions of the local ocular immune response in patients with inflammatory periocular disease.

Telomerase activity with concurrent loss of cell cycle regulation in feline post-traumatic ocular sarcomas.

Paraffin wax-embedded ocular globes of cats with post-traumatic ocular sarcomas were examined for the presence of TERT, the active subunit of telomerase. The latter is a ribonucleoprotein complex essential for immortalization and expressed by most malignant tumours, germ line cells, lens epithelial cells, and some stem cells. Due to the frequent loss of cell cycle control with the increased expression of telomerase activity, post-traumatic ocular sarcomas were also examined for loss of p16 expression and alterations in p53, the findings being related to mitotic score, tumour grade, and proliferating cell nuclear antigen. These sarcomas expressed telomerase at a high frequency (62.5%); in addition, the majority showed alterations in cell cycle control, as evaluated by lack of p16 immunolabelling (66.7%). Alterations in p53 were the sole mechanism by which cell cycle control was dysregulated in only two tumours expressing TERT (13%). These findings suggest that p16, and not p53, represents the primary mechanism by which post-traumatic ocular sarcomas that express telomerase activity escape cell cycle control.

The cultural context of psychology: questions for accurate research and appropriate practice.

This article summarizes the contents of the recent conference, "The Cultural Context of Psychology," held in New York City in August 1995. Using an innovative format of small-group discussions, 22 facilitators posed a total of over 100 key unanswered questions in multicultural psychology. There questions, organized along three categories-awareness, knowledge, and skills-form the foundation of this article. This article serves as a cognitive map for needed research and discussion on multicultural issues in mental health. The references were carefully selected to provide the interested reader with resources for follow-up work on the topics presented.

Acute cerebellar syndrome, conjunctivitis, and hearing loss associated with low-dose cytarabine administration.

An unusual reaction associated with chronic low-dose cytarabine is described. A 77-year-old man complained of three to four weeks of hearing loss and progressive inability to walk without assistance. He had received two courses of cytarabine 100 mg sc/wk for the management of myelofibrosis myeloid metaplasia over 21 months. He received a total of 3 g over seven months during his first course followed ten months later with a 1.2 g over four months. Conjunctivitis was also identified on physical examination at the time of his admission. He was admitted to the neurology service where a complete neurological work-up with consultations from the ophthalmology, audiology, hematology, and ear, nose, and throat services failed to identify a cause of his symptoms. Cytarabine was discontinued on the suspicion that his symptoms were drug induced. The conjunctivitis resolved completely with ophthalmic antibiotics and corticosteroids. His hearing slowly improved over three to four weeks, and he was able to ambulate with a walker. He continued to improve at home although some hearing loss remained three months after his initial presentation. Although conjunctivitis and neurotoxicity are well-known complications of high-dose cytarabine, there are no prior reports of these reactions after low-dose therapy. Hearing loss, which has not been previously reported with cytarabine alone, appears to be a new complication of cytarabine administration.