[Development of an asthenopia survey questionnaire for general surveys]

Objective: To design a visual fatigue questionnaire that can be used for population surveys. Methods: This was a cross-sectional study that involved three stages of subjects' recruitment. In the first stage, by convenience sampling, 150 individuals who complained of visual fatigue were selected at public places in Wenzhou City in May 2016. The 19-Item Asthenopia Survey Questionnaire (ASQ-19) was used to conduct the survey, and the questionnaire was adjusted. In the second stage, 200 outpatient participants were recruited from Wenzhou Medical University Affiliated Eye and Optometry Hospital from June 2016 to May 2017 and were divided into a visual fatigue group and a control group based on clinical diagnosis. The adjusted visual fatigue questionnaire was used for validation. In the third stage, 64 outpatient participants who met the inclusion criteria were continuously recruited from the Wenzhou Medical University Affiliated Eye and Optometry Hospital in July 2022. They were tested using the adjusted visual fatigue questionnaire and retested one week later. During the questionnaire adjustment stage, factor analysis and feedback were used to adjust the scoring method and items of the ASQ-19 questionnaire. The adjusted questionnaire was then analyzed for reliability, validity, accuracy, and subject acceptance during the validation and retest stages. Results: A total of 403 participants were included, and 456 questionnaires were distributed. Eventually, 432 valid questionnaires were collected from 379 participants, resulting in a valid response rate of 94.7%. During the questionnaire adjustment phase, there were 140 valid questionnaires from 140 participants consisting of 56 males and 84 females with an average age of (35.2±12.4) years. In the questionnaire validation phase, there were 186 valid questionnaires from 186 participants. Sixty-two participants had visual fatigue and 124 were controls. During the questionnaire retesting phase, 53 participants yielded 106 valid questionnaires. The group consisted of 20 males and 33 females with an average age of (22.8±4.9) years. After factor analysis, the symptom severity graded as none, mild, moderate, severe, and very severe was scored as 0, 1, 2, 3, and 4 points, respectively. The total score was 44, and the final questionnaire consisted of 11 items (numbered 1, 2, 3, 5, 6, 8, 10, 15, 17, 18, and 19). The 11-Item Asthenopia Survey Questionnaire (ASQ-11) had a Cronbach's α coefficient of 0.89, a split-half reliability of 0.82, and a test-retest Pearson correlation coefficient of 0.90 (P<0.001). The structural validity was 51.26%, and the discriminative validity was a t-value of 9.19 (P<0.001). On average, it took (2.82±0.43) minutes for participants to complete the questionnaire. The receiver operating characteristic curve had a cutoff value of 8.5, with a sensitivity of 74.19% and a specificity of 80.65%. Conclusion: The ASQ-11, with fewer items and a shorter completion time, is easy for participants to use and is suitable for screening or self-assessment of visual fatigue in the general population. Additionally, it is convenient for clinical and epidemiological studies related to visual fatigue.

3D Compartmentalised Human Pluripotent Stem Cell-derived Neuromuscular Co-cultures

Human neuromuscular diseases represent a diverse group of disorders with unmet clinical need, ranging from muscular dystrophies, such as Duchenne muscular dystrophy (DMD), to neurodegenerative disorders, such as amyotrophic lateral sclerosis (ALS). In many of these conditions, axonal and neuromuscular synapse dysfunction have been implicated as crucial pathological events, highlighting the need for in vitro disease models that accurately recapitulate these aspects of human neuromuscular physiology. The protocol reported here describes the co-culture of neural spheroids composed of human pluripotent stem cell (PSC)-derived motor neurons and astrocytes, and human PSC-derived myofibers in 3D compartmentalised microdevices to generate functional human neuromuscular circuits in vitro. In this microphysiological model, motor axons project from a central nervous system (CNS)-like compartment along microchannels to innervate skeletal myofibers plated in a separate muscle compartment. This mimics the spatial organization of neuromuscular circuits in vivo. Optogenetics, particle image velocimetry (PIV) analysis, and immunocytochemistry are used to control, record, and quantify functional neuromuscular transmission, axonal outgrowth, and neuromuscular synapse number and morphology. This approach has been applied to study disease-specific phenotypes for DMD and ALS by incorporating patient-derived and CRISPR-corrected human PSC-derived motor neurons and skeletal myogenic progenitors into the model, as well as testing candidate drugs for rescuing pathological phenotypes. The main advantages of this approach are: i) its simple design; ii) the in vivo-like anatomical separation between CNS and peripheral muscle; and iii) the amenability of the approach to high power imaging. This opens up the possibility for carrying out live axonal transport and synaptic imaging assays in future studies, in addition to the applications reported in this study. Graphical abstract Graphical abstract abbreviations: Channelrhodopsin-2 (CHR2+), pluripotent stem cell (PSC), motor neurons (MNs), myofibers (MFs), neuromuscular junction (NMJ).

CRISPR-mediated correction of skeletal muscle Ca2+ handling in a novel DMD patient-derived pluripotent stem cell model

Mutations in the dystrophin gene cause the most common and currently incurable Duchenne muscular dystrophy (DMD) characterized by progressive muscle wasting. Although abnormal Ca²⁺ handling is a pathological feature of DMD, mechanisms underlying defective Ca²⁺ homeostasis remain unclear. Here we generate a novel DMD patient-derived pluripotent stem cell (PSC) model of skeletal muscle with an isogenic control using clustered regularly interspaced short palindromic repeat (CRISPR)-mediated precise gene correction. Transcriptome analysis identifies dysregulated gene sets in the absence of dystrophin, including genes involved in Ca²⁺ handling, excitation-contraction coupling and muscle contraction. Specifically, analysis of intracellular Ca²⁺ transients and mathematical modeling of Ca²⁺ dynamics reveal significantly reduced cytosolic Ca²⁺ clearance rates in DMD-PSC derived myotubes. Pharmacological assays demonstrate Ca²⁺ flux in myotubes is determined by both intracellular and extracellular sources. DMD-PSC derived myotubes display significantly reduced velocity of contractility. Compared with a non-isogenic wildtype PSC line, these pathophysiological defects could be rescued by CRISPR-mediated precise gene correction. Our study provides new insights into abnormal Ca²⁺ homeostasis in DMD and suggests that Ca²⁺ signaling pathways amenable to pharmacological modulation are potential therapeutic targets. Importantly, we have established a human physiology-relevant in vitro model enabling rapid pre-clinical testing of potential therapies for DMD.

Nuclear Respiratory Factor 1 Overexpression Inhibits Proliferation and Migration of PC3 Prostate Cancer Cells

BACKGROUND/AIM

The role of nuclear respiratory factor 1 (NRF1) on the prostate cancer progression is controversial. We aimed to investigate the effect of NRF1 overexpression on the metastasis potential of PC3 prostate cancer cells and the associated molecular mechanisms.

MATERIALS AND METHODS

Cell survival, migration capacity, mitochondrial biogenesis, the expression of TGF-β signaling and EMT markers were examined after overexpression and silencing of NRF1 in PC3 cells.

RESULTS

We found that NRF1-overexpressing cells exhibited a decreased cell viability and proliferation ability as well as a reduced migration capacity compared to control cells. Moreover, ectopic expression of NRF1 increased the mitochondrial biogenesis and inhibited the EMT characteristics, including a decrease in the mesenchymal marker, α-SMA and an increase in the epithelial cell marker, E-cadherin. We also demonstrated that overexpression of NRF1 suppressed the expression of TGF-β signaling in PC3 cells. As expected, silencing of NRF1 reversed the abovementioned effects.

CONCLUSION

This study demonstrated that upregulation of NRF1 holds the potential to inhibit the metastasis of prostate cancer, possibly through an elevation of mitochondrial biogenesis and the subsequent repression of TGF-β-associated EMT. Therapeutic avenues that increase NRF1 expression may serve as an adjunct to conventional treatments of prostate cancer.

Investigating the role of dystrophin isoform deficiency in motor function in Duchenne muscular dystrophy

BACKGROUND

Duchenne muscular dystrophy (DMD) is caused by DMD mutations leading to dystrophin loss. Full-length Dp427 is the primary dystrophin isoform expressed in muscle and is also expressed in the central nervous system (CNS). Two shorter isoforms, Dp140 and Dp71, are highly expressed in the CNS. While a role for Dp140 and Dp71 on DMD CNS comorbidities is well known, relationships between mutations expected to disrupt Dp140 and Dp71 and motor outcomes are not.

METHODS

Functional outcome data from 387 DMD boys aged 4-15 years were subdivided by DMD mutation expected effects on dystrophin isoform expression; Group 1 (Dp427 absent, Dp140/Dp71 present, n = 201); Group 2 (Dp427/Dp140 absent, Dp71 present, n = 152); and Group 3 (Dp427/Dp140/Dp71 absent, n = 34). Relationships between isoform group and North Star ambulatory assessment (NSAA) scores, 10 m walk/run velocities and rise time velocities were explored using regression analysis. Western blot analysis was used to study Dp427, Dp140 and Dp71 production in myogenic cells (control and DMD human), control skeletal muscle, DMD skeletal muscle from the three isoform groups and cerebral cortex from mice (wild-type and DMD models). Grip strength and rotarod running test were studied in wild-type mice and DMD mouse models. DMD mouse models were mdx (Dp427 absent, Dp140/Dp71 present), mdx52 (Dp427/Dp140 absent, Dp71 present) and DMD-null (lacking all isoforms).

RESULTS

In DMD boys, mean NSAA scores at 5 years of age were 6.1 points lower in Group 3 than Group 1 (P < 0.01) and 4.9 points lower in Group 3 than Group 2 (P = 0.05). Mean peak NSAA scores were 4.0 points lower in Group 3 than Group 1 (P < 0.01) and 1.6 points lower in Group 2 than Group 1 (P = 0.04). Mean four-limb grip strength was 1.5 g/g lower in mdx52 than mdx mice (P = 0.003) and 1.5 g/g lower in DMD-null than mdx mice (P = 0.002). Dp71 was produced in myogenic cells (control and DMD human) and skeletal muscle from humans in Groups 1 and 2 and mdx mice, but not skeletal muscle from human controls, myogenic cells and skeletal muscle from humans in Group 3 or skeletal muscle from wild-type, mdx52 or DMD-null mice.

CONCLUSIONS

Our results highlight the importance of considering expected effects of DMD mutations on dystrophin isoform production when considering patterns of DMD motor impairment and the implications for clinical practice and clinical trials. Our results suggest a complex relationship between dystrophin isoforms expressed in the brain and DMD motor function.

The extracellular vesicular pseudogene LGMNP1 induces M2-like macrophage polarization by upregulating LGMN and serves as a novel promising predictive biomarker for ovarian endometriosis recurrence

STUDY QUESTION

How does ectopic endometrial stromal cell (Ecto-ESC)-derived extracellular vesicular Legumain pseudogene 1 (EV-LGMNP1), a newly identified pseudogene of Legumain (LGMN), contribute to M2-phenotype macrophage polarization, and does it predict recurrence in patients with ovarian endometriosis (EMs)?

SUMMARY ANSWER

EV-LGMNP1, which is abundant in Ecto-ESCs and serum from ovarian EMs, can direct macrophages towards an M2 phenotype by upregulating LGMN expression and is a promising biomarker for predicting ovarian EMs recurrence.

WHAT IS KNOWN ALREADY

Extracellular vesicles (EVs) can mediate cell-to-cell crosstalk to promote disease progression via cargo molecule transport. Recently, LGMNP1, a newly identified pseudogene of LGMN, has been reported to promote cancer progression by upregulating LGMN. LGMN is a well-studied protein that can induce M2-like polarization.

STUDY DESIGN, SIZE, DURATION

An in vitro study was conducted with Ecto-ESCs isolated from ectopic endometrial samples, collected from two patients with ovarian EMs (diagnosed by laparoscopy and histological analysis). A clinical retrospective cohort study of 52 ovarian EMs patients and 21 controls with available preoperative serum samples was carried out (2013-2017). The follow-up period ended either at the time of recurrence or on 31 December 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ecto-ESC-derived EVs (EV/Ecto-ESCs) were characterized by nanoparticle tracking analysis, transmission electron microscopy and western blotting. EV internalization by THP-1 cells, which are the most widely used primary human macrophages model, was detected by fluorescence labelling. After EV treatment, THP-1 cell polarization was detected by quantitative real-time PCR (qRT-PCR) and western blot analyses of CD86 (M1-related marker) and CD206 (M2-related marker). LGMNP1 mRNA expression level in EVs from both primary ectopic endometrioc stromal cells and serum was examined using qRT-PCR. Additionally, the expression of LGMN, the downstream target gene of LGMNP1, in THP-1 cells was evaluated using qRT-PCR and western blotting. Kaplan-Meier and multivariate Cox regression analyses were applied to evaluate the independent predictive factors of EMs recurrence-free survival. A novel nomogram model based on serum EV-LGMNP1 was then formulated to predict EMs recurrence.

MAIN RESULTS AND THE ROLE OF CHANCE

In vitro assays demonstrated that EV/Ecto-ESCs drove macrophages towards an M2-like phenotype. Moreover, LGMNP1 contributed to EV/Ecto-ESC-induced M2 macrophage polarization by upregulating LGMN mRNA expression levels. Clinically, serum EV-LGMNP1 was more highly expressed in recurrent EMs patients than in controls and EMs patients without recurrence. Survival analysis and our novel nomogram reconfirmed that serum EV-LGMNP1 was a novel promising and meaningful non-invasive biomarker for predicting EMs recurrence.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

In vitro experiments were only performed on samples from two patients with ovarian endometriosis, and a larger sample size is needed. ESCs isolated from the eutopic endometrium of EMs and non-EMs patients should be studied in the future. Additionally, in vitro experiments should be performed using endometrial epithelium cells and further in vivo experiments, such as using mice endometriotic models to investigate whether EV/Ecto could induce M2 macrophage polarization, should be conducted. Moreover, multicentre, large-sample data are needed to validate our predictive nomogram model.

WIDER IMPLICATIONS OF THE FINDINGS

Our study provides novel insights into the mechanism of M2 polarization involved in ovarian EMs progression mediated by an 'EV-shuttled pseudogene LGMNP1' mode. In addition, serum EV-LGMNP1 may serve as a novel non-invasive biomarker for predicting recurrence, providing a new therapeutic target for ovarian EMs.

STUDY FUNDING/COMPETING INTEREST(S)

This project was supported by funding from the National Natural Science Foundation of China (81971361), the Natural Science Foundation of Shanghai Science and Technology (19ZR1406900), the Shanghai 'Rising Stars of Medical Talent' Youth Development Program (AB83030002019004), the Clinical Research Plan of SHDC (SHDC2020CR4087), the Shanghai Municipal Health Commission (202040498), the Research and Innovation Project of the Shanghai Municipal Education Commission (2019-01-07-00-07-E00050) and the Clinical Research Plan of SHDC (SHDC2020CR1045B). There are no competing interests to declare.

Comparative epigenetic analysis of tumour initiating cells and syngeneic EPSC-derived neural stem cells in glioblastoma

Epigenetic mechanisms which play an essential role in normal developmental processes, such as self-renewal and fate specification of neural stem cells (NSC) are also responsible for some of the changes in the glioblastoma (GBM) genome. Here we develop a strategy to compare the epigenetic and transcriptional make-up of primary GBM cells (GIC) with patient-matched expanded potential stem cell (EPSC)-derived NSC (iNSC). Using a comparative analysis of the transcriptome of syngeneic GIC/iNSC pairs, we identify a glycosaminoglycan (GAG)-mediated mechanism of recruitment of regulatory T cells (Tregs) in GBM. Integrated analysis of the transcriptome and DNA methylome of GBM cells identifies druggable target genes and patient-specific prediction of drug response in primary GIC cultures, which is validated in 3D and in vivo models. Taken together, we provide a proof of principle that this experimental pipeline has the potential to identify patient-specific disease mechanisms and druggable targets in GBM.

Optogenetic modeling of human neuromuscular circuits in Duchenne muscular dystrophy with CRISPR and pharmacological corrections

Duchenne muscular dystrophy (DMD) is caused by dystrophin gene mutations leading to skeletal muscle weakness and wasting. Dystrophin is enriched at the neuromuscular junction (NMJ), but how NMJ abnormalities contribute to DMD pathogenesis remains unclear. Here, we combine transcriptome analysis and modeling of DMD patient-derived neuromuscular circuits with CRISPR-corrected isogenic controls in compartmentalized microdevices. We show that NMJ volumes and optogenetic motor neuron–stimulated myofiber contraction are compromised in DMD neuromuscular circuits, which can be rescued by pharmacological inhibition of TGFβ signaling, an observation validated in a 96-well human neuromuscular circuit coculture assay. These beneficial effects are associated with normalization of dysregulated gene expression in DMD myogenic transcriptomes affecting NMJ assembly (e.g., MUSK) and axon guidance (e.g., SLIT2 and SLIT3). Our study provides a new human microphysiological model for investigating NMJ defects in DMD and assessing candidate drugs and suggests that enhancing neuromuscular connectivity may be an effective therapeutic strategy.

[Epidemiological characteristics of imported malaria cases in Fujian Province from 2014 to 2018]

OBJECTIVE

To analyze the epidemiological characteristics of imported malaria cases in Fujian Province from 2014 to 2018, so as to provide scientific basis for the development of the control strategy for imported malaria.

METHODS

The epidemiological data of malaria cases in Fujian Province from 2014 to 2018 were retrieved from the Notifiable Disease Reporting System and Parasitic Disease Information Reporting System of Chinese Center for Disease Control and Prevention, and the classification, origin of infections, temporal distribution, spatial distribution, population distribution, reporting institutions and diagnosis were analyzed.

RESULTS

A total of 540 overseas imported malaria cases were reported in Fujian Province from 2014 to 2018, and all cases were laboratory-confirmed, including 398 cases with falciparum malaria, 88 cases with vivax malaria, 38 cases with ovale malaria, 14 cases with malariae malaria and 2 cases with mixed infections. There were 90.56% (489/540) of the imported malaria cases with infections in 27 African countries, 5.92% (32/540) with infections in 5 Asian countries and 3.52% (19/540) with infections in one Oceania country. There was no significant seasonal distribution of the cases, and the imported malaria cases were predominantly detected in Fuzhou City (80.00%, 432/540) and at ages of 20 to 49 years (81.48%, 440/540). Initial diagnosis was predominantly at the city-level medical institutions, and 77.96% (421/540) were diagnosed as malaria at the initial diagnosis institutions. The median duration from onset to initial diagnosis was 2 days and 70.19% (379/540) were diagnosed within 3 days of onset. The interval between initial diagnosis and definitive diagnosis was 0 day, with 85.37% (461/540) definitively diagnosed within 3 days of initial diagnosis.

CONCLUSIONS

Overseas imported malaria is a continuous problem challenging the malaria elimination programme of Fujian Province. Improving the healthcare-seeking awareness and the diagnostic capability of healthcare workers, and intensifying the monitoring and management of malaria among overseas labors are strongly recommended.

[Clinical effect of X-N advancement flap in repairing pressure ulcer on the buttock or back]

Objective: To explore the clinical effect of X-N advancement flap in repairing pressure ulcer on the buttock or back. Methods: From June 2018 to June 2019, 20 patients with grade Ⅳ pressure ulcers on the buttock or back were hospitalized and treated in the Department of Traumatology, Burns and Plastic Surgery of Fourth Affiliated Hospital of Guangxi Medical University, including 15 males and 5 females, aged 48-89 years. The area of the patient's wound was 8 cm×5 cm-15 cm×12 cm after debridement, and all were repaired with the X-N advancement flap designed by the author. The flap was designed according to the direction of skin relaxation on both sides of the wound, and the skin was incised in X-shape and sutured in N-shape. The width and advancement distance of the flap were recorded, and the ratio of the advancement distance to the width of the flap was calculated. The flap survival, complication, and follow-up were observed and recorded. Results: The width of the flap was (5.9±1.2) cm, the advancement distance of the flap was (10.3±2.5) cm, and the ratio of the advancement distance to the width of the flap was 1.8±0.4. All the flaps survived, and none of the flaps had blood flow disorder. Local dehiscence occurred in the flap of one patient 1 week after surgery, which was healed after laying on the floating bed, strengthened care, and wound dressing change. The flap of one patient developed infection 5 days after surgery, which was healed after partial suture removal, smooth drainage, and replacement with sensitive antibiotics. The wounds of the remaining 18 patients were all cured. After 3 months of follow-up, the flaps survived well with good elasticity and texture. Conclusions: The X-N advancement flap can make the skin and soft tissue move forward effectively. It is simple and effective to repair pressure ulcers on the back or buttock of patients with this flap, which is worthy of clinical promotion and application.

[Survey on the quadrivalent influenza vaccine intention and related factors of health care workers in the Pearl River Delta region from 2015 to 2017]

Objective: To analyze the quadrivalent influenza vaccine intention of 718 health care workers (HCWs) in the Pearl River Delta region from 2015 to 2017. Method: In May 2018, 718 HCWs from the department related to the diagnosis and treatment of influenza in 17 hospitals (6 tertiary hospitals, 5 secondary hospitals and 6 primary hospitals) from Guangzhou, Jiangmen, Zhuhai and Dongguan were selected by using stratified sampling method. Questionnaire survey and face-to-face interview were used to collect the information of influenza vaccination, the intention of the quadrivalent influenza vaccine, the acceptance of free and required vaccination policies, and recommendations for increasing influenza vaccination intentions from 2015 to 2017. The multivariate logistic regression was used to analyze factors associated with the vaccination intention. Results: A total of 718 HCWs were surveyed and 147 of them were interviewed face to face. Among them, the vaccination rate of primary hospitals [17.39%(40/230)] was higher than that of other hospitals (χ(2)=15.80, P<0.05). If the vaccine could be free, 84.82% (609/718) of HCWs would like to be vaccinated. The multivariate logistic regression showed that the factors, HCWs who were aged ≥50 years (OR=3.44, 95%CI:1.43-8.28), worked in department of prevention and health care (OR=2.35, 95%CI:1.16-4.75), learned about the quadrivalent influenza vaccine (OR=2.94, 95%CI:2.08-4.18), knowed that HCWs are priority (OR=2.33, 95%CI:1.56-3.48), and had a history of trivalent influenza vaccination from 2015 to 2017 (OR=4.70, 95%CI:3.08-7.15), were associated with the vaccination intention. Conclusion: HCWs in the Pearl River Delta region had weak inclination of getting quadrivalent influenza vaccine. HCWs who were age (≥50 years old), worked in department of prevention and health care, learned about the quadrivalent influenza vaccine, knowed that HCWs are priority, and had a history of trivalent influenza vaccination from 2015 to 2017 were factors positively associated with the vaccination intention.

Expression of Mucin 1 in salivary gland tumors and its correlation with clinicopathological factors

This study aimed to detect the expression of Mucin 1 (MUC1) in acinic cell carcinoma (AciCC) of salivary gland and to explore the relationship between MUC1 and clinicopathological factors of AciCC of salivary gland. Patients with salivary gland tumors who were treated at our hospital were enrolled in this study. The pathological sections collected from all subjects were classified by histological examinations. In addition, 40 cases of primary salivary gland AciCC tissues were selected and classified into experimental group, whereas 40 cases of normal salivary gland (NSG) tissues were selected and classified into control group. MUC1 positive cells in both experimental and control groups were detected by immunohistochemistry assays, while all clinical data were analyzed statistically. The results showed that MUC1 was only expressed in the ductal epithelium of NSG and distributed at the apical side of the cell membrane. In primary salivary gland AciCC tissues, scattered expressions of MUC1 were found both on the cell membrane and in the cytoplasm of tumor cells, and sometimes even in the cell nuclei, thus completely eliminating the polarized distribution of MUC1 expressions. The percentage of MUC1 positive cells in experimental group was significantly higher than that in control group (P < 0.05). In addition, the expression of MUC1 in salivary gland AciCC was correlated with gender, age, histological type, lesion location, cervical lymph node metastasis, local recurrence, and distant metastasis. In conclusion, MUC1 is related to the occurrence and development of salivary gland AciCC. Therefore, MUC1 may be used as a novel tumor marker in the clinical diagnosis and treatment of salivary gland AciCC.

TNF-α was involved in calcium hydroxide-promoted osteogenic differentiation of human DPSCs through NF-κB/p38MAPK/Wnt pathway

It has been reported that calcium hydroxide can induce proliferation, migration, and mineralization in dental pulp stem cells (DPSCs), but the underlying molecular mechanisms are still unclear. In this study, we sought to explore the role of calcium hydroxide in the cell proliferation and directional differentiation of DPSCs and to study the regulatory effect of NF-κB, p38MAPK, and Wnt signaling on differentiation of DPSCs. CCK8 cell assay, Wound Healing Assay, and Alkaline Phosphatase Staining Assay were respectively used to determine the proliferation rate, migration and ALP expression of DPSCs. Alizarin Red Staining Assay was used to observe the mineralization of DPSCs. RT-PCR analysis and Western Blot Analysis displayed the expression of related fators at mRNA and protein level, respectively. In the present study, we found that NF-κB, p38MAPK, and Wnt signaling could abolish calcium hydroxide-induced proliferation of DPSCs. The inhibition of NF-κB, p38MAPK, and Wnt signaling suppressed the migration, ALP expression, and mineralization of DPSCs. NF-κB, p38MAPK, and Wnt signaling involved in directional differentiation of DPSCs. Moverover, calcium hydroxide could activate NF-κB, p38MAPK, and Wnt pathway by regulating TNF-α. Our study showed that NF-κB, p38MAPK, and Wnt signaling pathway were involved in calcium hydroxide-induced proliferation, migration, mineralization, and osteogenic differentiation in DPSCs. Calcium hydroxide affected NF-κB, p38MAPK, and Wnt pathway by regulating TNF-α.

Electro-optic spectral tuning in a fan-out double-prism domain periodically poled lithium niobate intracavity optical parametric oscillator

We report on the design and experimental demonstration of an electro-optically tunable, pulsed intracavity optical parametric oscillator (IOPO) based on a unique fan-out double-prism domain periodically poled lithium niobate (DPD PPLN) in a diode-pumped Nd:YVO₄ laser. The PPLN device combines the functionalities of fan-out and ramped duty-cycle domain structured nonlinear crystals, working simultaneously as a continuous grating-period quasi-phase-matched optical parametric downconverter and an electro-optic beam deflector/Q switch in the laser system. When driving the fan-out DPD PPLN with a voltage pulse train and varying the DC offset of the pulse train, a pulsed IOPO was realized with its signal and idler being electro-optically tunable over the 1880 and 2453 nm bands at spectral tuning rates of 13.5 (measured) and 25.8 (calculated) nm/(kV/mm), respectively.

The functional O-mannose glycan on α-dystroglycan contains a phospho-ribitol primed for matriglycan addition

Multiple glycosyltransferases are essential for the proper modification of alpha-dystroglycan, as mutations in the encoding genes cause congenital/limb-girdle muscular dystrophies. Here we elucidate further the structure of an O-mannose-initiated glycan on alpha-dystroglycan that is required to generate its extracellular matrix-binding polysaccharide. This functional glycan contains a novel ribitol structure that links a phosphotrisaccharide to xylose. ISPD is a CDP-ribitol (ribose) pyrophosphorylase that generates the reduced sugar nucleotide for the insertion of ribitol in a phosphodiester linkage to the glycoprotein. TMEM5 is a UDP-xylosyl transferase that elaborates the structure. We demonstrate in a zebrafish model as well as in a human patient that defects in TMEM5 result in muscular dystrophy in combination with abnormal brain development. Thus, we propose a novel structure—a ribitol in a phosphodiester linkage—for the moiety on which TMEM5, B4GAT1, and LARGE act to generate the functional receptor for ECM proteins having LG domains.

DOI:http://dx.doi.org/10.7554/eLife.14473.001

Carrier transport in quantum dot quantum well microstructures of the self-assembled CdTe/CdS/ligand core-shell system

The study on the quantum dot quantum well (QDQW) microstructure modified by choosing different ligands containing a sulfhydryl group is of significance because it enables one to regulate photoexcited free charge carriers' (FCCs') transport behaviours in high-quality CdTe/ligand QDs via a self-assembled way. The photoelectron characteristics of ligand-capped CdTe nanoparticles were probed by a combination of surface photovoltaic (SPV) and photoacoustic technologies, supplemented by a computer simulation method of the CASTEP module. The experiment reveals that the D-value ΔEWi obtained by the associated two parameters of the SPV spectroscopy was closely related to the quantum confinement energy in the self-assembled CdTe/CdS/ligand core-shell system. In the paper the D-value was termed the depth of QWs, which were buried in the space charge regions located in the graded-band-gap and on either side of the shell-CdS. Obvious resonance quantum tunnelling may occur in the energy band structure with deep QWs on using certain ligands, resulting in an extended diffusion length of the FCCs on illumination of the photon energy hν ≥ Eg, core-CdTe, and in a strong SPV response at a specific wavelength region. In addition, the carrier-longitudinal optical phonon interaction is the reciprocal of the carriers' lifetime. The d-frontier orbital in the graded-band-gap plays an important role in both the microstructure and the resonance quantum tunnelling of the QDQW system according to the CASTEP calculations.

GPX2 underexpression indicates poor prognosis in patients with urothelial carcinomas of the upper urinary tract and urinary bladder

PURPOSE

Oxidative stress is believed to be one of the important etiologies in carcinogenesis that has not been systemically investigated in urothelial carcinoma (UC). Through data mining from a published transcriptomic database of UC of urinary bladders (UBUCs) (GSE31684), glutathione peroxidase 2 (GPX2) was identified as the most significant downregulated gene among those response to oxidative stress (GO:0006979). We therefore analyze GPX2 transcript and protein expressions and its clinicopathological significance.

METHODS

Real-time RT-PCR assay was used to detect GPX2 mRNA level in 20 fresh UBUC specimens. Immunohistochemistry was used to determine GPX2 protein expression in 340 urothelial carcinomas of upper tracts (UTUCs) and 295 UBUCs with mean/median follow-up of 44.7/38.9 and 30.8/23.1 months, respectively. Its expression status was further correlated with clinicopathological features and evaluated for its impact on disease-specific survival and metastasis-free survival (MeFS).

RESULTS

Decrease in GPX2 transcript level was associated with both higher pT and positive nodal status in 20 UBUCs (all p < 0.05). GPX2 protein underexpression was also significantly associated with advanced pT status, nodal metastasis, high histological grade, vascular invasion, and frequent mitoses in both groups of UCs (all p < 0.05). GPX2 underexpression not only predicted dismal DDS and MeFS at univariate analysis, but also implicated worse DDS (UTUC, p = 0.002; UBUC, p = 0.029) and MeFS (UTUC, p = 0.001; UBUC, p = 0.032) in multivariate analysis.

CONCLUSIONS

GPX2 underexpression is associated with advanced tumor status and implicated unfavorable clinical outcome of UCs, suggesting its role in tumor progression and may serve as a theranostic biomarker of UCs.

Efficacy of fexofenadine in isolated rat tracheas

OBJECTIVES

Histamine is an important chemical mediator in both nasal and bronchial inflammation in patients with allergic rhinitis and asthma. The effect of histamine receptor-1 antagonists on nasal mucosa in vivo is well known, however, the effect on tracheal smooth muscle has rarely been explored. The purpose of this study was to determine the effects of fexofenadine on isolated tracheal smooth muscle in vitro.

METHODS

Six tracheal strips were used for each experiment, and one untreated strip served as a control. We examined the effectiveness of fexofenadine on isolated rat tracheal smooth muscle by testing the effect on: 1) tracheal smooth muscle resting tension; 2) contraction caused by 10E-6 M methacholine as a parasympathetic mimetic; and 3) electrically induced tracheal smooth muscle contractions.

RESULTS

The results indicated that addition of methacholine caused the trachea to contract in a dose-dependent manner. The addition of fexofenadine at a dose of 10E-4 M elicited a significant relaxation response compared to 10E-6 M methacholine-induced contraction. There were no detectable changes in the peak tension of electrical field stimulation-induced contractions in the fexofenadine group.

CONCLUSION

High concentrations of fexofenadine had an anti-cholinergic effect. In addition to diminishing histamine-mediated allergic symptoms, fexofenadine may have a potentially therapeutic implication in alleviating asthma-related symptoms due to reducing methacholine-induced contractions of tracheal smooth muscle though these aspects were not studied.

Mutations in GDP-mannose pyrophosphorylase B cause congenital and limb-girdle muscular dystrophies associated with hypoglycosylation of α-dystroglycan

Congenital muscular dystrophies with hypoglycosylation of α-dystroglycan (α-DG) are a heterogeneous group of disorders often associated with brain and eye defects in addition to muscular dystrophy. Causative variants in 14 genes thought to be involved in the glycosylation of α-DG have been identified thus far. Allelic mutations in these genes might also cause milder limb-girdle muscular dystrophy phenotypes. Using a combination of exome and Sanger sequencing in eight unrelated individuals, we present evidence that mutations in guanosine diphosphate mannose (GDP-mannose) pyrophosphorylase B (GMPPB) can result in muscular dystrophy variants with hypoglycosylated α-DG. GMPPB catalyzes the formation of GDP-mannose from GTP and mannose-1-phosphate. GDP-mannose is required for O-mannosylation of proteins, including α-DG, and it is the substrate of cytosolic mannosyltransferases. We found reduced α-DG glycosylation in the muscle biopsies of affected individuals and in available fibroblasts. Overexpression of wild-type GMPPB in fibroblasts from an affected individual partially restored glycosylation of α-DG. Whereas wild-type GMPPB localized to the cytoplasm, five of the identified missense mutations caused formation of aggregates in the cytoplasm or near membrane protrusions. Additionally, knockdown of the GMPPB ortholog in zebrafish caused structural muscle defects with decreased motility, eye abnormalities, and reduced glycosylation of α-DG. Together, these data indicate that GMPPB mutations are responsible for congenital and limb-girdle muscular dystrophies with hypoglycosylation of α-DG.

First Report of Cowpea mild mottle virus in Cowpea and French Bean in Taiwan

In 2009, more than 50% of vine type French beans were found bearing severe viral symptoms in a vegetable garden in Nantou County, Taiwan. Infected plants were stunted and exhibited pronounced mottling symptoms on their leaves. The symptomatic plants were mechanically inoculated on Chenopodium quinoa and local lesions developed 7 to 10 days after inoculation. The virus source established by back isolation the single lesion from C. quinoa on French beans developed symptoms similar to those found in the field. Host range test showed that this isolate could only infect leguminous plants, including soybean, mung bean, pea, peanut, asparagus bean, cowpea, adzuki bean, and lima bean, but not cucurbitaceous and solanaceous plants. Since only Cucumber mosaic virus (CMV) has been reported in Taiwan to induce similar symptoms in French beans, we tested both the field collected and inoculated French beans by CMV antiserum in ELISA but obtained a negative result. Due to subsequent electron microscopy studies that found potyvirus and carlavirus like particles in the leaf dips of infected French beans, we conducted reverse transcription (RT)-PCR using generic degenerate primers for potyviruses (Hrp5/Pot1 (2) and PotZ/Pot1 (3)) and carlaviruses (Decarla-u2 (5'-TGCACTGARTCMGAYTATGARGCYTT-3' and Decarla-d1 (5'-GCACATRTCRTCVCCDGCAAA-3') previously designed in our lab. No amplification was found from the potyvirus primers, while the carlavirus one gave an expected amplicon of 285 bp, which was found sharing 81% nucleotide sequence identity with the replicase gene of Cowpea mild mottle virus (CpMMV) (GenBank Accession No. FJ560903). A primer pair (CpMMV-CPu: 5'-TTTACTCTTAggTWATggAgTC-3' and CpMMV-CPd: 5'-CCTATTAAAACACACAAHTCAAA-3') was thus designed to amplify the complete coat protein (CP) gene based on the reported CP sequences and obtained an expected 867-bp product from our French bean isolate. This 867-bp sequence (JX020701) was confirmed to have 97.6% amino acid sequence identities with the CP gene of a Puerto Rican CpMMV isolate (GU191840). In a separate survey, another isolate from asparagus bean (CpMMV-V) causing mild mottling symptom was obtained. Analyses of the CP gene of CpMMV-V (JX070669) confirmed that it shared 88.8% and 97.8% of nucleotide and amino acid sequence identities with the French bean isolate, respectively. Different from most carlaviruses with aphid transmissibility, CpMMV has been shown to be transmitted non-persistently by whiteflies (1). Both CpMMV isolates from Taiwan were confirmed to be transmitted by silver leaf whiteflies (Bemicia argentifolii Bellows and Perring). This is the first record of whitefly transmissible legume virus in Taiwan. Since whitefly has been a problem in agriculture worldwide, CpMMV can be a new emerging threat for Taiwan's legume crop production. References: (1) M. Iwaki et al. Plant Dis. 66:365, 1982. (2) S. S. Pappu et al. J. Virol. Methods 41:9, 1993. (3) F. M. Zerbini et al. Phytopathology 85:746.

Mutations in B3GALNT2 cause congenital muscular dystrophy and hypoglycosylation of α-dystroglycan

Mutations in several known or putative glycosyltransferases cause glycosylation defects in α-dystroglycan (α-DG), an integral component of the dystrophin glycoprotein complex. The hypoglycosylation reduces the ability of α-DG to bind laminin and other extracellular matrix ligands and is responsible for the pathogenesis of an inherited subset of muscular dystrophies known as the dystroglycanopathies. By exome and Sanger sequencing we identified two individuals affected by a dystroglycanopathy with mutations in β-1,3-N-acetylgalactosaminyltransferase 2 (B3GALNT2). B3GALNT2 transfers N-acetyl galactosamine (GalNAc) in a β-1,3 linkage to N-acetyl glucosamine (GlcNAc). A subsequent study of a separate cohort of individuals identified recessive mutations in four additional cases that were all affected by dystroglycanopathy with structural brain involvement. We show that functional dystroglycan glycosylation was reduced in the fibroblasts and muscle (when available) of these individuals via flow cytometry, immunoblotting, and immunocytochemistry. B3GALNT2 localized to the endoplasmic reticulum, and this localization was perturbed by some of the missense mutations identified. Moreover, knockdown of b3galnt2 in zebrafish recapitulated the human congenital muscular dystrophy phenotype with reduced motility, brain abnormalities, and disordered muscle fibers with evidence of damage to both the myosepta and the sarcolemma. Functional dystroglycan glycosylation was also reduced in the b3galnt2 knockdown zebrafish embryos. Together these results demonstrate a role for B3GALNT2 in the glycosylation of α-DG and show that B3GALNT2 mutations can cause dystroglycanopathy with muscle and brain involvement.

Missense mutations in β-1,3-N-acetylglucosaminyltransferase 1 (B3GNT1) cause Walker-Warburg syndrome

Several known or putative glycosyltransferases are required for the synthesis of laminin-binding glycans on alpha-dystroglycan (αDG), including POMT1, POMT2, POMGnT1, LARGE, Fukutin, FKRP, ISPD and GTDC2. Mutations in these glycosyltransferase genes result in defective αDG glycosylation and reduced ligand binding by αDG causing a clinically heterogeneous group of congenital muscular dystrophies, commonly referred to as dystroglycanopathies. The most severe clinical form, Walker–Warburg syndrome (WWS), is characterized by congenital muscular dystrophy and severe neurological and ophthalmological defects. Here, we report two homozygous missense mutations in the β-1,3-N-acetylglucosaminyltransferase 1 (B3GNT1) gene in a family affected with WWS. Functional studies confirmed the pathogenicity of the mutations. First, expression of wild-type but not mutant B3GNT1 in human prostate cancer (PC3) cells led to increased levels of αDG glycosylation. Second, morpholino knockdown of the zebrafish b3gnt1 orthologue caused characteristic muscular defects and reduced αDG glycosylation. These functional studies identify an important role of B3GNT1 in the synthesis of the uncharacterized laminin-binding glycan of αDG and implicate B3GNT1 as a novel causative gene for WWS.

Muscle diseases in the zebrafish

Animal models in biomedical research are important for understanding the pathological mechanisms of human diseases at a molecular and cellular level. Several aspects of mammalian animals, however, may limit their use in modelling neuromuscular disorders. Many attributes of zebrafish (Danio rerio) are complementary to mammalian experimental systems, establishing the zebrafish as a powerful model organism in disease biology. This review focuses on a number of key studies using the zebrafish to model hereditary muscle diseases with additional emphasis on recent advances in zebrafish functional genomics and drug discovery. Increasing research in zebrafish disease models, combined with knowledge from mammalian models, will bring novel insights into the disease pathogenesis of neuromuscular disorders, as well as facilitate the development of effective therapeutic strategies.

Two-dimensional PPLN for simultaneous laser Q-switching and optical parametric oscillation in a Nd:YVO4 laser

We report on a tunable intracavity optical parametric oscillator (IOPO) achieved using a two-dimensional (2D) periodically poled lithium niobate (PPLN) as simultaneously an electro-optic (EO) Bragg Q-switch and an optical frequency mixer (OFM) in a diode-pumped Nd:YVO(4) laser. The 2D periodic domain inversion structure is designed to provide two orthogonal reciprocal vectors to respectively satisfy the phase-matching conditions required by the two quasi-phase-matching devices (i.e., the PPLN EO Bragg deflector and the PPLN OFM). At a ~140-V Q-switching voltage and a 1-kHz switching rate, we obtained a signal wave at 1550 nm with a pulse energy of 9.7 μJ (corresponding to a peak power of ~2.4 kW) from the IOPO at 9.1-W diode pump power. Simultaneously we also observed multi-wavelength generation from the system originating in the single-pass parametric conversions in the 2D nonlinear photonic crystal structure. Temperature tuning of the IOPO signal wavelength in the eye-safe region was also demonstrated.

Recent Chlamydia pneumoniae infection is highly associated with active ankylosing spondylitis in a Chinese cohort

OBJECTIVE

The aim of the present study was to investigate the presence of anti-Chlamydia pneumoniae (Cp) antibodies in patients with ankylosing spondylitis (AS) to determine whether there is an association with AS disease activity.

METHODS

Seventy-nine AS outpatients and 73 normal controls were enrolled in this case-control study. Serum anti-Cp immunoglobulins (CpIg) were detected by enzyme-linked immunosorbent assay (ELISA). Antibodies to Epstein-Barr virus (EBV), cytomegalovirus (CMV), and Chlamydia trachomatis (Ct) were also measured. Clinical and experimental data were collected, and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) was determined. Patients with positive Cp IgM or Cp IgA were considered to have had a recent Cp infection.

RESULTS

Cp IgG was detected in the majority of AS patients and also controls (88.8% vs. 91.8%, respectively). The seroprevalence of Cp IgA and Cp IgM was significantly higher in AS patients than in the controls (51.9% vs. 31.5%, p = 0.010 for Cp IgA; 79.7% vs. 20.5%, p < 0.0001 for Cp IgM). Seropositivity of Cp IgM was associated with elevation of the disease activity index, including erythrocyte sedimentation rate (ESR; p = 0.021), C-reactive protein (CRP; p = 0.007) and the BASDAI (p = 0.009). Persistent positive Cp IgM was associated with active disease, while seroreversion of Cp IgM was associated with a reduction in these disease activity indices. There was no correlation between Cp IgM or Cp IgA and symptomatic upper respiratory infections or other clinical manifestations.

CONCLUSIONS

Recent Cp infections occur frequently in AS patients and Cp IgM antibody is correlated with active disease. These findings indicate that Cp infections may be a triggering factor for active AS.

Zebrafish Fukutin family proteins link the unfolded protein response with dystroglycanopathies

Allelic mutations in putative glycosyltransferase genes, fukutin and fukutin-related protein (fkrp), lead to a wide range of muscular dystrophies associated with hypoglycosylation of α-dystroglycan, commonly referred to as dystroglycanopathies. Defective glycosylation affecting dystroglycan–ligand interactions is considered to underlie the disease pathogenesis. We have modelled dystroglycanopathies in zebrafish using a novel loss-of-function dystroglycan allele and by inhibition of Fukutin family protein activities. We show that muscle pathology in embryos lacking Fukutin or FKRP is different from loss of dystroglycan. In addition to hypoglycosylated α-dystroglycan, knockdown of Fukutin or FKRP leads to a notochord defect and a perturbation of laminin expression before muscle degeneration. These are a consequence of endoplasmic reticulum stress and activation of the unfolded protein response (UPR), preceding loss of dystroglycan–ligand interactions. Together, our results suggest that Fukutin family proteins may play important roles in protein secretion and that the UPR may contribute to the phenotypic spectrum of some dystroglycanopathies in humans.

Effects of mechanical stimuli on the synthesis of superficial zone protein in chondrocytes

Superficial zone protein (SZP) has been demonstrated to contribute to the boundary lubrication in synovial joints. This study was designed to clarify the modulation of SZP expression by mechanical stress in articular chondrocytes. Cyclic tensile strains of 7 and 21% cell elongation were applied to cultured chondrocytes obtained from porcine mandibular condylar cartilage. The mRNA levels of SZP, IL-1 beta, and TGF-beta1 were examined by a quantitative real-time PCR analysis. Protein level of SZP was examined by Western blotting. The SZP mRNA level was significantly upregulated after 12, 24, and 48 h by 7% elongation. Although SZP mRNA level was upregulated by 21% elongation after 12 h, it decreased to a lower level than the control after 48 h. The TGF-beta1 mRNA level exhibited an almost similar change to SZP. The IL-1 beta mRNA level was not changed markedly by 7% elongation. However, the IL-1 beta mRNA level was significantly increased by a 12-h application of 21% elongation. Western blot analysis revealed that the SZP expression was increased by 7% elongation, but decreased remarkably by 21% elongation. It is suggested from these findings that the SZP expression level in the chondrocytes is enhanced by optimal mechanical stimuli, but inhibited by excessive loading partly affected by TGF-beta1 and IL-1 beta, leading to the deterioration of joint lubrication.

Fiber-laser-pumped CW OPO for red, green, blue laser generation

We report a CW, watt-level, red, green, and blue (RGB) laser pumped by an economical multimode (1-nm linewidth) Yb-fiber laser at 1.064 mum. A singly resonant optical parametric oscillator at 1.56 mum has two intracavity sum-frequency generators for red and blue laser generation. An extracavity second harmonic generator converts the residual pump power into green laser radiation. At 25-W pump power, the laser generated 3.9, 0.456, and 0.49 W at 633, 532, and 450 nm, respectively. The multimode pump laser offers a large temperature bandwidth for operating the RGB OPO without the need of a precision crystal temperature stabilizer.

Thermal waveguide OPO

We report a mid-infrared, CW singly resonant optical parametric oscillator (OPO) with a thermally induced waveguide in its gain crystal. We measured a numerical aperture of 0.0062 for the waveguide at 80-W intracavity power at 3.2 microm. This thermal-guiding effect benefits to the stable operation of an OPO and improves the parametric conversion efficiency by more than a factor of two when compared with that without thermal guiding.

Desmosine as a biomarker of elastin degradation in COPD: current status and future directions

Desmosine (DES) and isodesmosine (IDES) are two unusual, tetrafunctional, pyridinium ring-containing amino acids involved in elastin cross-linking. Being amino acids unique to mature, cross-linked elastin, they are useful for discriminating peptides derived from elastin breakdown from precursor elastin peptides. According to these features, DES and IDES have been extensively discussed as potentially attractive indicators of elevated lung elastic fibre turnover and markers of the effectiveness of agents with the potential to reduce elastin breakdown. In the present manuscript, immunology-based and separation methods for the evaluation of DES and IDES are discussed, along with studies reporting increased levels of urine excretion in chronic obstructive pulmonary disease (COPD) patients with and without alpha(1)-antitrypsin deficiency. The results of the application of DES and IDES as surrogate end-points in early clinical trials in COPD are also reported. Finally, recent advances in detection techniques, including liquid chromatography tandem mass spectrometry and high-performance capillary electrophoresis with laser-induced fluorescence, are discussed. These techniques allow detection of DES and IDES at very low concentration in body fluids other than urine, such as plasma or sputum, and will help the understanding of whether DES and IDES are potentially useful in monitoring therapeutic intervention in COPD.

The robotic radiosynthesis of 5-[(18)F]fluoro-2'-deoxyuridine and its biological characterization

5-[(18)F]fluoro-2'-deoxyuridine ([(18)F]FUdR) was synthesized using a robotic system as a proliferation probe for PET. [(18)F]FUdR was prepared via radiofluorodestannylation reaction from its organotin precursor. Biodistribution study and microPET imaging of [(18)F]FUdR in NG4TL4 sarcoma-bearing FVB/n mice were performed. The tumor-to-blood and tumor-to-muscle ratio increased steadily from 15 (1.81 and 3.42) to 120min (9.10 and 11.9) post injection. The dynamic microPET imaging demonstrates remarkable radioactivity retention in the tumor, which is consistent with the results of biodistribution study.

Molecular dissection of Drosophila Prickle isoforms distinguishes their essential and overlapping roles in planar cell polarity

Prickle-Spiny-Legs (Pk) is an essential component of the planar cell polarity (PCP) pathway, together with Frizzled (Fz) and Dishevelled (Dsh). A role for Pk was proposed to mediate feedback amplification of asymmetric Fz/Dsh activity across cell boundaries, ensuring a single prehair initiates at each distal vertex. Here we show that apical localisation of Pk(Pk) and Pk(Sple) isoforms are mutually independent and regulated by the C-terminal domain. The N-terminus of Pk(Pk) is dispensable for PCP, whereas the unique N-terminal domain of Pk(Sple) contains an additional localisation function, which confers a qualitatively different activity. Our results suggest that endogenous Pk(Pk) and Pk(Sple) can affect each other's function via the C-terminal domain, yet may not form heteromeric complexes. Overexpressing PET domain-deleted Pk variants interferes with a branch of Fz/Dsh signalling that regulates the number of wing hairs, and blocks non-cell-autonomous repolarisation. We infer that Pk(Pk) is sufficient to mediate the intercellular feedback signalling. Significantly, Pk(Pk) but not Pk(Sple) is required for hexagonal cell packing in the pupal wing. We propose that Fz-dependent PCP readout reflects short-range, cell-contact based, interactions between hexagonal cells, rather than a direct response to an as yet unidentified diffusible ligand.

Observation of thermal-induced optical guiding and bistability in a mid-IR continuous-wave, singly resonant optical parametric oscillator

We report the observation of thermal-induced optical guiding and bistability in a mid-IR cw, singly resonant optical parametric oscillator (SRO) at approximately 3.2 microm. The SRO employs a MgO:PPLN crystal as the gain medium and a 1-nm-linewidth Yb-fiber laser at 1.064 microm as the pump source. As soon as the pump power reaches the thermal guiding threshold at 16.5 W, the SRO shows a step increase in the parametric efficiency by a factor of 2.5. At 25 W pump power, the SRO generated 5.3 and 1.2 W at 1.58 and 3.23 microm, respectively, with single-longitudinal-mode performance for the 3.23 microm radiation.

Low-threshold, narrow-line THz-wave parametric oscillator with an intra-cavity grazing-incidence grating

We report a low-threshold, narrow-line THz-wave parametric oscillator with an intra-cavity grazing-incidence grating and a 1-mm thick, 45-mm long lithium-niobate planar waveguide. When pumped by an actively Q-switched Nd:YAG laser, the threshold energy and intensity of the parametric oscillator were about 2.2 mJ and 70 MW/cm(2), respectively. The linewidths of the output THz wave were 12 and 134 GHz with and without the intra-cavity grating, respectively.

Forward and backward terahertz-wave difference-frequency generations from periodically poled lithium niobate

We report terahertz-wave generation in the wavelength range of 190 - 210 and 457 - 507 microm from forward and backward difference frequency generations, respectively, in a 3.2-cm long multi-grating periodically poled lithium niobate (PPLN) crystal. The grating period of the PPLN crystal varies form 63 to 70 microm in 1-microm increments. The extraordinary refractive index of lithium niobate in the THz-wave range was precisely deduced from the quasi-phase-matching condition of the difference frequency generations.

Monolithically integrated laser Bragg Q-switch and wavelength converter in a PPLN crystal

We report a periodically poled lithium niobate (PPLN) crystal for both temperature-insensitive laser Q-switching and temperature-tuned wavelength conversion. The PPLN crystal consists of two sections, a 20.3-mum period section functioning as an electro-optic Bragg grating for Qswitching a diode-pumped Nd:YVO4 laser at 1064 nm and a 31-mum-period section functioning as an optical parametric generator for down converting the generated 1064-nm laser. When driving the PPLN Bragg grating with 170-V voltage pulses, we measured 181 muJ pulse energy at 1064 nm from the Nd:YVO4 laser pumped by 20.4 W diode power. The 181-muJ pulsed laser was further converted into mid-infrared radiation in the monolithic PPLN crystal with 35% parametric efficiency. The wavelengths were broadly tunable in the range of 1.75-1.88 mum (signal) and 2.7-2.44 mum (idler) via temperature without affecting the performance of the PPLN Bragg Qswitch.

Electro-optic periodically poled lithium niobate Bragg modulator as a laser Q-switch

We report an electro-optic Bragg modulator using a periodically poled lithium niobate (PPLN) crystal. We measured a half-wave voltage of 160 V when transmitting a 1064 nm laser through a 14.2 mm long, 780 microm thick, 20.13 microm period PPLN crystal at the Bragg angle. We also demonstrated a Q-switched Nd:YVO(4) laser using such a PPLN Bragg modulator as its Q-switch, producing 7.8 ns, 201 microJ pulses at a 10 kHz repetition rate when pumped by a 19.35 W diode laser at 808 nm.

Light-enhanced electro-optic spectral tuning in annealed proton-exchanged periodically poled lithium niobate channel waveguides

We report the observation of light-enhanced electro-optic spectral tuning in annealed proton-exchanged, asymmetric domain-duty-cycle periodically poled lithium niobate (PPLN) channel waveguides for second-harmonic generation. The spectral tuning rate was increased rapidly from 0.07 nm/(kV/mm) to a saturated value of 0.32 nm/(kV/mm) in a 30%/70% domain-duty-cycle PPLN waveguide when the fundamental pump power near 1534 nm was increased from 0.6 to 46 mW. The second-harmonic laser power at 767 nm was identified to be the source enhancing the spectral tuning.

Single-longitudinal-mode, tunable dual-wavelength,CW Nd:YVO(4) laser

We report a single-longitudinal-mode CW diode-pumped Nd:YVO(4) laser emitting at both 1064 and 1342 nm with 10% optical efficiency at 20-W pump power. The measured spectral widths at 1064 and 1342 nm were less than 450 MHz and 400 MHz, respectively. The two emission wavelengths can be independently tuned over the lasing bandwidths of the dual-wavelength laser.