Impact of Nicotine Exposure on Hair Cell Toxicity and Embryotoxicity During Zebrafish Development

Objectives Nicotine has various adverse effects including negative impacts associated with maternal exposure. In the current study, we examined nicotine-induced damage of hair cells and embryotoxicity during zebrafish development. Methods Zebrafish embryos were exposed to nicotine at several concentrations (5, 10, 20, and 40 μM) and embryotoxicity were evaluated at 72 hours, including hatching rate, mortality, teratogenicity rate, and heart rate. Hair cells within the supraorbital (SO1 and SO2), otic (O1), and occipital (OC1) neuromasts were identified at 120 hours. Apoptosis and mitochondrial damage of hair cells were analyzed using TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling) and DASPEI (2-[4-(dimethylamino)styryl]-N-ethylpyridinium iodide) assays, respectively, and changes of ultrastructure were observed by scanning electron microscopy. Results The control group without nicotine appeared normal with overall mortality and teratogenicity rate <5%. The hatching rate and mortality rate was not significantly different according to nicotine concentration (n=400 each). The abnormal morphology rate (n=400) increased and heart rate (n=150) decreased with increasing nicotine concentration (P<0.05). Nicotine-induced hair cell damage significantly increased as nicotine concentration increased. A significantly greater number of TUNEL-positive cells (P<0.01) and markedly smaller DASPEI area (P<0.01) were shown as nicotine concentration increased. Conclusion The current results suggest that nicotine induces dose-dependent hair cell toxicity in embryos by promoting apoptosis and mitochondrial and structural damage

Low expression of CD40L in tumor-free lymph node of oral cavity cancer related with poor prognosis

Recently, the genetic alterations associated with tumor progression and impaired host immunity against transformed cells draw increased attention. Here, we characterized the differential gene expression patterns and protein expression in tumor-free lymph node from recurrent and non-recurrent tumors to identify independent prognostic markers for oral squamous cell carcinoma (OSCC). A cDNA microarray analysis was performed to identify the differentially expressed genes in regional tumor-free lymph nodes from OSCC patients with and without recurrence. Then, the protein expression of the selected genes was analyzed by immunohistochemistry in 60 OSCC patients to determine their association with survival. Widespread down-regulation of genes involved in antigen processing and recognition in lymph nodes was a distinctive feature. In univariate Kaplan-Meier analysis, lower expression of CD40L and CD80 in tumor-free lymph nodes was significantly correlated with poorer survival. In multivariate Cox regression analysis, CD40L was identified as an independent prognostic marker of disease-free survival. Our data indicate that impaired host immunity (decreased CD40L expression) along with the TNM staging might be an important factor determining the prognosis of OSCC.N

Watching helical membrane proteins fold reveals a common N-to-C-terminal folding pathway

To understand membrane protein biogenesis, we need to explore folding within a bilayer context. Here, we describe a single-molecule force microscopy technique that monitors the folding of helical membrane proteins in vesicle and bicelle environments. After completely unfolding the protein at high force, we lower the force to initiate folding while transmembrane helices are aligned in a zigzag manner within the bilayer, thereby imposing minimal constraints on folding. We used the approach to characterize the folding pathways of the Escherichia coli rhomboid protease GlpG and the human ??2-adrenergic receptor. Despite their evolutionary distance, both proteins fold in a strict N-to-C-terminal fashion, accruing structures in units of helical hairpins. These common features suggest that integral helical membrane proteins have evolved to maximize their fitness with cotranslational folding

Sodium Selenite Acts as an Otoprotectant against Neomycin-Induced Hair Cell Damage in a Zebrafish Model.

Sodium selenite is a trace element essential for many physiological functions in the body. It is involved in various biological processes; it acts as a cofactor for antioxidant enzymes that protect against free radicals and is reported to limit metal-mediated oxidative DNA damage. In the present study, we investigated the effect of sodium selenite on neomycin ototoxicity in wild-type and transgenic zebrafish (Brn3C: EGFP). Five or six days post-fertilization, zebrafish larvae were co-exposed to 125 μM neomycin and various concentrations (10 μM, 100 μM, 250 μM, and 500 μM) of sodium selenite for 1 h. Hair cells within neuromasts of the supraorbital (SO1 and SO2), otic (O1), and occipital (OC1) lateral lines were analyzed by fluorescence microscopy (n = 10 fish per treatment). Hair cell survival was estimated as the ratio of the hair cell numbers in each group compared to those of the control group that were not exposed to neomycin. Apoptosis and hair cell damage of neuromasts were evaluated using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) assay and 2-[4-(dimethylamino) styryl]-N-ethylpyridinium iodide (DASPEI) assay, respectively. Ultrastructural changes were evaluated using scanning electron microscopy and transmission electron microscopy. Neuromast hair cells were preserved in zebrafish exposed to 125 μM neomycin and 500 μM sodium selenite for 1 h. Sodium selenite protected against neomycin-induced hair cell loss of neuromasts, reduced apoptosis, and prevented zebrafish ultrastructural changes. We propose that sodium selenite protects against neomycin-induced hair cell damage by inhibiting apoptosis, decreasing the disarray of stereocilia, and preventing ultrastructural changes in the neuromast hair cells of the zebrafish

Impact of tonsillectomy on pediatric psychological status

OBJECTIVE: Tonsillectomy is one of the most commonly performed procedures in children. However, parents often hesitate to agree to the procedure because of concerns of the possible harmful impact on their child's psychological health. The present study was performed to examine the short-term psychological impact on children who had undergone tonsillectomy. METHODS: Forty-three pediatric patients aged 3-11 years who underwent tonsillectomy were enrolled in the study. Postoperative pain was assessed using a 10-point visual analog scale (VAS) on postoperative days 1, 2, 7, and 21. The Korean version of the Child Behavior Checklist (K-CBCL) was given to the parents of the children to evaluate the psychosocial effect of tonsillectomy on the preoperative day and on postoperative day 21. RESULTS: There were no significant differences in postoperative pain according to age, tonsil size, degree of adhesion, or operation time. There was no significant relationship between postoperative pain score and K-CBCL score. Sociality, total behavioral problems, externalizing problems, internalizing problems, anxiety/depression, social immaturity, and emotional lability domain scores on the K-CBCL were improved significantly. CONCLUSIONS: Improvements in general emotional and social status were observed at 3 weeks after tonsillectomy. Tonsillectomy itself does not have a harmful effect on children's psychological status

The effect 1hr exposure of 500 μM sodium selenite on zebrafish development.

<p>The viability of 6 days post-fertilization zebrafish, three days after the treatment with 500 μM sodium selenite for 1 hr, was evaluated. There were no noticeable developmental differences between zebrafish treated with sodium selenite compare to those of the negative control group.</p

Transmission electron microscopy (TEM).

<p>TEM of Normal control (A and B); TEM of zebrafish treated with 125 μM neomycin only (C-E); TEM of zebrafish treated with 125 μM neomycin and 500 μM sodium selenite (F-H). The sterocilia (black asterisk) and the kinocilium (K) from each hair cell are clearly visible (× 8K) (A). A normal-sized mitochondria (arrow, × 25K) (B). The hair cells were severely damaged and showed a condensed nuclei (black asterisk) and pyknotic nuclei (white asterisk) (× 20K) (C). The collapse of the apical surface of neuromasts was typically evident. A hair cell showed extrusion of cytoplasm (black asterisk) and the swollen mitochondria (arrow) (× 20K) (D).Severely damaged hair cells show a severely degenerating cytoplasm (black asterisk), a fragmenting condensed nucleus (white asterisk), and multiple swollen mitochondria (M) (× 30K) (E).When 500 μM sodium selenite was applied, structure of neruomasts were nearly complete protected. Nuclear damage such as condensed cytoplasm and pyknotic nuclei were not showed. (× 5 K) (F). The structure of the stereocilia (black asterisk) and the kinocilium(K) are preserved (× 20 K) (G). The normal-sized nucleus (black asterisk) and mitochondria (arrow) is shown (× 20 K) (H). NM, neomycin; S, sodium selenite; HC, hair cell; SC, supporting cell; CC, crescent cell; MC, mantle cell; BM, basement membrane. Scale bars (at the top or the bottom of each figure, one space) = 5μm (A); 2μm (B); 2μm(C); 1μm (D); 1 μm (E); 2μm (F); 2μm (G); 2μm (H). NM, neomycin; S, sodium selenite. Images were obtained in three 5-dpf zebrafish for each group.</p