Macrophage recruitment and epithelial repair following hair cell injury in the mouse utricle

The sensory organs of the inner ear possess resident populations of macrophages, but the function of those cells is poorly understood. In many tissues, macrophages participate in the removal of cellular debris after injury and can also promote tissue repair. The present study examined injury-evoked macrophage activity in the mouse utricle. Experiments used transgenic mice in which the gene for the human diphtheria toxin receptor (huDTR) was inserted under regulation of the Pou4f3 promoter. Hair cells in such mice can be selectively lesioned by systemic treatment with diphtheria toxin (DT). In order to visualize macrophages, Pou4f3-huDTR mice were crossed with a second transgenic line, in which one or both copies of the gene for the fractalkine receptor CX3CR1 were replaced with a gene for GFP. Such mice expressed GFP in all macrophages, and mice that were CX3CR1GFP/GFP lacked the necessary receptor for fractalkine signaling. Treatment with DT resulted in the death of ~70% of utricular hair cells within seven days, which was accompanied by increased numbers of macrophages within the utricular sensory epithelium. Many of these macrophages appeared to be actively engulfing hair cell debris, indicating that macrophages participate in the process of ‘corpse removal’ in the mammalian vestibular organs. However, we observed no apparent differences in injury-evoked macrophage numbers in the utricles of CX3CR1+/GFP mice vs. CX3CR1GFP/GFP mice, suggesting that fractalkine signaling is not necessary for macrophage recruitment in these sensory organs. Finally, we found that repair of sensory epithelia at short times after DT-induced hair cell lesions was mediated by relatively thin cables of F-actin. After 56 days recovery, however, all cell-cell junctions were characterized by very thick actin cables

Texture-Modified Diets Need to be Improved

Purpose : The aim of this study is to compare the nutritional status of older adult inpatients consuming Texture-Modified Diets (TMD) to older adult inpatients consuming a regular diet. Methods : The study was designed as cross-sectional and was conducted in three large hospitals in northern Vietnam. The data for 344 older adult inpatients were collected in 2021 by dietitians. Results : The result showed 104 subjects were prescribed TMD. The textures of hospital diets have still not been adequately developed. In particular, the hospitals had not yet developed pureed meals. All older adult inpatients (74.7 ± 6.8 years old, 52.9% female) had 28.8% malnutrition by the GLIM criteria. The TMD group had a malnutrition prevalence two times higher than the regular diet group. Total energy intake from hospital meal and outside snacks in the regular diet group was higher than in the TMD group, about 150 kcal. Although energy provided from the hospital diet in both groups was similar, hospital meal wastage in the TMD group was higher than in the regular diet group. Conclusion : The older adult inpatients on TMD may have a nutritional status worse than those consuming a regular diet. Hospital diets need to be improved in texture and quality

Comparing Organizational Patterns of L1 and L2 Opinion Texts Written by Japanese EFL Students

This study compared second language (L2) and first language (L1) writing organizational patterns of English as a Foreign Language (EFL) Japanese students. Previous research involving Japanese L1 writers\u27 L2 writing organizational choices revealed tendencies towards inductive as well as deductive patterns. Early studies found students tended to employ inductive patterns, whereas recent studies have found students tended to employ deductive patterns. These differences can be derived from multiple factors involved in L2 writing, such as the participants\u27 L2 proficiency levels, L1 and L2 writing abilities, L1 and L2 writing experiences, L1 and L2 writing instructional backgrounds, and the writing tasks. As a follow-up to Hirose (2003), the present study, using a within-subject desig, examined L1 (Japanese) and L2 (English) organizational patterns of Japanese EFL students (N=70) who had not yet received L2 writing instruction. More specifically, the study investigated students\u27 choices of organization patterns in relation to the organization and overall quality of L1 and L2 opinion texts. The results found that (a) regardless of their writing levels, most students showed their preference for deductive patterns in both L1 and L2 ; (b) quite a few of them did not organize their texts either deductively or inductively, implying they apparently had problems in organizing their texts in both languages ; and (c) there was no significant relation between students\u27 writing abilities and their choice of organizational patterns. Finally, possible implications of the results are discussed as they pertain to L1 and L2 writing research and pedagogy. Several directions for future research are also suggested

Fractalkine signaling regulates macrophage recruitment into the cochlea and promotes the survival of spiral ganglion neurons after selective hair cell lesion

Macrophages are recruited into the cochlea in response to injury caused by acoustic trauma or ototoxicity, but the nature of the interaction between macrophages and the sensory structures of the inner ear remains unclear. The present study examined the role of fractalkine signaling in regulating the injury-evoked behavior of macrophages following the selective ablation of cochlear hair cells. We used a novel transgenic mouse model in which the human diphtheria toxin receptor (huDTR) is selectively expressed under the control of Pou4f3, a hair cell-specific transcription factor. Administration of diphtheria toxin (DT) to these mice resulted in nearly complete ablation of cochlear hair cells, with no evident pathology among supporting cells, spiral ganglion neurons, or cells of the cochlear lateral wall. Hair cell death led to an increase in macrophages associated with the sensory epithelium of the cochlea. Their numbers peaked at 14 days after DT and then declined at later survival times. Increased macrophages were also observed within the spiral ganglion, but their numbers remained elevated for (at least) 56 d after DT. To investigate the role of fractalkine signaling in macrophage recruitment, we crossed huDTR mice to a mouse line that lacks expression of the fractalkine receptor (CX(3)CR1). Disruption of fractalkine signaling reduced macrophage recruitment into both the sensory epithelium and spiral ganglion and also resulted in diminished survival of spiral ganglion neurons after hair cell death. Our results suggest a fractalkine-mediated interaction between macrophages and the neurons of the cochlea. SIGNIFICANCE STATEMENT It is known that damage to the inner ear leads to recruitment of inflammatory cells (macrophages), but the chemical signals that initiate this recruitment and the functions of macrophages in the damaged ear are unclear. Here we show that fractalkine signaling regulates macrophage recruitment into the cochlea and also promotes the survival of cochlear afferents after selective hair cell lesion. Because these afferent neurons carry sound information from the cochlea to the auditory brainstem, their survival is a key determinant of the success of cochlear prosthetics. Our data suggest that fractalkine signaling in the cochlea is neuroprotective, and reveal a previously uncharacterized interaction between cells of the cochlea and the innate immune system