Wnt-PLC-IP3-Connexin-Ca2+ axis maintains ependymal motile cilia in zebrafish spinal cord.

Ependymal cells (ECs) are multiciliated neuroepithelial cells that line the ventricles of the brain and the central canal of the spinal cord (SC). How ependymal motile cilia are maintained remains largely unexplored. Here we show that zebrafish embryos deficient in Wnt signaling have defective motile cilia, yet harbor intact basal bodies. With respect to maintenance of ependymal motile cilia, plcδ3a is a target gene of Wnt signaling. Lack of Connexin43 (Cx43), especially its channel function, decreases motile cilia and intercellular Ca2+ wave (ICW) propagation. Genetic ablation of cx43 in zebrafish and mice diminished motile cilia. Finally, Cx43 is also expressed in ECs of the human SC. Taken together, our findings indicate that gap junction mediated ICWs play an important role in the maintenance of ependymal motile cilia, and suggest that the enhancement of functional gap junctions by pharmacological or genetic manipulations may be adopted to ameliorate motile ciliopathy.

A zebrafish model of nondystrophic myotonia with sodium channelopathy.

Nondystrophic myotonias are disorders of Na+ (Nav1.4 or SCN4A) and Cl- (CLCN1) channels in skeletal muscles, and frequently show phenotype heterogeneity. The molecular mechanism underlying their pathophysiology and phenotype heterogeneity remains unclear. As zebrafish models have been recently exploited for studies of the pathophysiology and phenotype heterogeneity of various human genetic diseases, a zebrafish model may be useful for delineating nondystrophic myotonias. Here, we generated transgenic zebrafish expressing a human mutant allele of SCN4A, referred to as Tg(mylpfa:N440K), and needle electromyography revealed increased number of myotonic discharges and positive sharp waves in the muscles of Tg(mylpfa:N440K) than in controls. In addition, forced exercise test at a water temperature of 24 °C showed a decrease in the distance moved, time spent in and number of visits to the zone with stronger swimming resistance. Finally, a forced exercise test at a water temperature of 18 °C exhibited a higher number of dive-bombing periods and drifting-down behavior than in controls. These findings indicate that Tg(mylpfa:N440K) is a good vertebrate model of exercise- and cold-induced human nondystrophic myotonias. This zebrafish model may contribute to provide insight into the pathophysiology of myotonia in sodium channelopathy and could be used to explore a new therapeutic avenue.

The relationship between intention to leave the hospital and coping methods of emergency nurses after workplace violence.

AIMS AND OBJECTIVES: To identify the relationship between emergency nurses' intention to leave the hospital and their coping methods following workplace violence. BACKGROUND: Emergency departments report a high prevalence of workplace violence, with nurses being at particular risk of violence from patients and patients' relatives. Violence negatively influences nurses' personal and professional lives and increases their turnover. DESIGN: This is a cross-sectional, descriptive survey study. METHODS: Participants were nurses (n = 214) with over one year of experience of working in an emergency department. We measured workplace violence, coping after workplace violence experiences and job satisfaction using scales validated through a preliminary survey. Questionnaires were distributed to all nurses who signed informed consent forms. Multiple logistic regression analysis was used to identify the relationships between nurses' intention to leave the hospital and their coping methods after workplace violence. RESULTS: Verbal abuse was the most frequent violence experience and more often originated from patients' relatives than from patients. Of the nurses who experienced violence, 61.0% considered leaving the hospital. As for coping, nurses who employed problem-focused coping most frequently sought to identify the problems that cause violence, while nurses who employed emotion-focused coping primarily attempted to endure the situation. The multiple logistic regression analysis revealed that female sex, emotion-focused coping and job satisfaction were significantly related to emergency nurses' intention to leave. CONCLUSIONS: Emotion-focused coping seems to have a stronger effect on intention to leave after experiencing violence than does job satisfaction. RELEVANCE TO CLINICAL PRACTICE: Nurse managers should begin providing emergency nurses with useful information to guide their management of violence experiences. Nurse managers should also encourage nurses to report violent experiences to the administrative department rather than resorting to emotion-focused coping. Nurses should be provided with the opportunity to communicate their feelings to their colleagues.

Primary Cilia Negatively Regulate Melanogenesis in Melanocytes and Pigmentation in a Human Skin Model.

The primary cilium is an organelle protruding from the cell body that senses external stimuli including chemical, mechanical, light, osmotic, fluid flow, and gravitational signals. Skin is always exposed to the external environment and responds to external stimuli. Therefore, it is possible that primary cilia have an important role in skin. Ciliogenesis was reported to be involved in developmental processes in skin, such as keratinocyte differentiation and hair formation. However, the relation between skin pigmentation and primary cilia is largely unknown. Here, we observed that increased melanogenesis in melanocytes treated with a melanogenic inducer was inhibited by a ciliogenesis inducer, cytochalasin D, and serum-free culture. However, these inhibitory effects disappeared in GLI2 knockdown cells. In addition, activation of sonic hedgehog (SHH)-smoothened (Smo) signaling pathway by a Smo agonist, SAG inhibited melanin synthesis in melanocytes and pigmentation in a human skin model. On the contrary, an inhibitor of primary cilium formation, ciliobrevin A1, activated melanogenesis in melanocytes. These results suggest that skin pigmentation may be regulated partly by the induction of ciliogenesis through Smo-GLI2 signaling.

Dexmedetomidine preconditioning attenuates Cisplatin-induced ototoxicity in zebrafish.

OBJECTIVES: Utilisation of high-frequency drills is known to increase noise induced hearing loss due to increasing the damages of inner ear cells. This study aimed to investigate whether preconditioning by using dexmedetomidine (DEX) decreased the occurrence of ischemia in inner cells of the ear. METHODS: We utilised a transgenic zebrafish line Brn3C, and the embryos were collected from breeding adult zebrafish. Five-day-old larvae were cultured at the density of 50 embryos, and the larvae were classified into 4 groups: control, cisplatin group, DEX group, and DEX+yohimbine; adrenoreceptor blocker group. The DEX group was categorised into 3 subgroups by dosage; 0.1, 1, and 10 µM. Preconditioning was performed for 150 minutes and then exposed to cisplatin for 6 hours. The experiment was performed in 7 replicates for each group and the number of hair cells in 3 parts of the neuromasts of each fish was determined. RESULTS: Hair cell apoptosis by cisplatin was attenuated more significantly in the DEX preconditioning group than in the control group. However, the preconditioning effects were not blocked by yohimbine. CONCLUSION: The results of this study suggest that hearing loss caused by vibration-induced noise could be reduced by using DEX and may occur through other mechanisms rather than adreno-receptors.

Therapeutic effect of intracameral amphotericin B injection in the treatment of fungal keratitis.

PURPOSE: To study the therapeutic efficacy of intracameral amphotericin B (ICAMB) injection in the treatment of fungal keratitis. METHODS: Fourteen patients with fungal keratitis received ICAMB, 10 microg/0.1 mL (group A), and 17 patients received conventional treatment only (group B). Visual acuity, time to hypopyon disappearance, time to epithelial defect closure, time to final improvement, and final outcome were analyzed and compared between the 2 groups. The concentration of amphotericin B in the aqueous humor after injection was measured using high-performance liquid chromatography. RESULTS: The mean final visual acuity (log MAR) was 1.6 +/- 1.1 in group A and 1.3 +/- 1.4 in group B (P = 0.24). The mean time to disappearance of hypopyon, epithelial defect closure, and final improvement was 9.4 +/- 9.4, 19.8 +/- 10.4, and 26.6 +/- 9.2 days in group A and 26.7 +/- 21.3 (P = 0.03), 32.6 +/- 22.8 (P = 0.08), and 52.8 +/- 38.2 days (P = 0.04) in group B, respectively. At the last follow-up, treatment success was achieved in 92.9% of group A and 82.4% of group B (P = 0.38). The mean concentration of intracameral amphotericin B was 601.6 +/- 51.3 ng/mL at 6 hours, 98.8 +/- 43.1 ng/mL at 1 day, 57.0 +/- 11.6 ng/mL at 3 days, and 52.3 +/- 8.3 ng/mL at 7 days after injection. CONCLUSIONS: ICAMB seems to be effective in reducing time to disappearance of hypopyon and final improvement in the treatment of fungal keratitis.

Interleukin-6 and tumor necrosis factor-alpha levels in tears of patients with dry eye syndrome.

PURPOSE: To determine the levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in tears of patients with dry eye syndrome. METHODS: IL-6 and TNF-alpha levels were measured by enzyme-linked immunosorbent assay in tear samples obtained from 18 patients with dry eye (8 patients with Sjögren syndrome and 10 patients with non-Sjögren syndrome) and 14 control subjects. The correlation between IL-6 and TNF-alpha levels and tear film and ocular surface parameters was analyzed. The relative expression of these cytokines was evaluated in conjunctival impression cytology and conjunctival biopsy specimens by using immunohistochemical staining. RESULTS: The mean levels of IL-6 and TNF-alpha were, respectively, 18.57 +/- 8.92 and 3.68 +/- 3.45 pg/mL in patients with dry eye and 3.59 +/- 3.38 (P < 0.01) and < 0.5 (P < 0.01) pg/mL in control subjects. IL-6 level was significantly increased in tears of patients with Sjögren syndrome compared with those with non-Sjögren syndrome (P < 0.01). IL-6 level correlated significantly with tear film breakup time (P = 0.04), Schirmer test (P < 0.01), tear clearance (P = 0.02), keratoepithelioplasty score (P < 0.01), and goblet cell density (P = 0.03), but not with corneal sensitivity (P = 0.08). There was no significant difference in TNF-alpha level between patients with non-Sjögren and Sjögren syndrome. TNF-alpha levels did not correlate with tear film and ocular surface parameters. Immunohistochemical staining showed positive staining for IL-6 in specimens from patients with dry eye, especially in specimens from patients with Sjögren syndrome. CONCLUSION: IL-6 and TNF-alpha levels are elevated in tears of patients with dry eye syndrome. IL-6 level, but not TNF-alpha level, is associated with the severity of the disease and correlates with various tear film and ocular surface parameters.

Experimental inhibition of corneal neovascularization by photodynamic therapy with verteporfin.

PURPOSE: To investigate the anti-angiogenic effects of photodynamic therapy with verteporfin in a rabbit model of corneal neovascularization. METHODS: One week after suturing, the localization of verteporfin in the neovascularized cornea was examined through fluorescent microscopy 1 hr after administration. Rabbits were treated with one or two times of photodynamic therapy with verteporfin at 1-week intervals. Analysis of corneal neovascularization was performed by biomicroscopic and histological examinations. RESULTS: Fluorescent microscopy showed green fluorescence in the vascular walls and interstitial tissue of the corneal stroma. The mean percentages of neovascularized corneal area at 3 days, 1 week, and 2 weeks after one time of photodynamic therapy were 90.3% +/- 3.5%, 71.6% +/- 6.2%, and 43.6% +/- 15.1% in treated eyes and 96.4% +/- 1.9% (p = 0.10), 88.6% +/- 4.6% (p = 0.01), and 76.8% +/- 4.4% (p < 0.01) in control eyes, respectively. The mean percentages 3 days, 1 week, and 2 weeks after two times of photodynamic therapy were also significantly lower in treated eyes compared with control eyes. In quantitative histological examination at 1 and 2 weeks after therapy, treated eyes showed significantly less neovascular area and number of vessels than control eyes. CONCLUSIONS: Photodynamic therapy with verteporfin is a safe and useful procedure to reduce experimental corneal neovascularization and can be used to inhibit angiogenesis in the cornea.

Therapeutic effect of umbilical cord serum eyedrops for persistent corneal epithelial defect.

PURPOSE: To evaluate the therapeutic effect of umbilical cord serum in the treatment of persistent epithelial defect of the cornea. METHODS: Fourteen eyes of 14 patients with persistent epithelial defect that had persisted for at least 2 weeks despite conventional treatment were treated with 20% umbilical cord serum eyedrops six times a day. The images of the epithelial defects were captured using a camera attached to a slit lamp biomicroscope and the areas of the epithelial defects were calculated. Treatment was considered effective for epithelial defect healing within 2 weeks, partially effective for healing within 2 to 4 weeks, and ineffective for healing requiring either more than 1 month or additional measures. RESULTS: Mean duration of epithelial defect before treatment was 7.2 +/- 6.3 weeks, and mean area was 7.86 +/- 7.32 mm2. Umbilical cord serum therapy was effective in 6 eyes (42.9%), partially effective in 6 (42.9%), and ineffective in 2 (14.2%). Nevertheless, the epithelial defects in both the ineffective eyes were eventually healed within 8 weeks. Mean healing time in effective or partially effective cases was 2.75 +/- 1.06 weeks. CONCLUSIONS: The use of umbilical cord serum eyedrops for the treatment of persistent epithelial defect is effective.