Subgenomic promoter recognition by the norovirus RNA-dependent RNA polymerases.

The replication enzyme of RNA viruses must preferentially recognize their RNAs in an environment that contains an abundance of cellular RNAs. The factors responsible for specific RNA recognition are not well understood, in part because viral RNA synthesis takes place within enzyme complexes associated with modified cellular membrane compartments. Recombinant RNA-dependent RNA polymerases (RdRps) from the human norovirus and the murine norovirus (MNV) were found to preferentially recognize RNA segments that contain the promoter and a short template sequence for subgenomic RNA synthesis. Both the promoter and template sequence contribute to stable RdRp binding, accurate initiation of the subgenomic RNAs and efficient RNA synthesis. Using a method that combines RNA crosslinking and mass spectrometry, residues near the template channel of the MNV RdRp were found to contact the hairpin RNA motif. Mutations in the hairpin contact site in the MNV RdRp reduced MNV replication and virus production in cells. This work demonstrates that the specific recognition of the norovirus subgenomic promoter is through binding by the viral RdRp.

Relative peripheral refraction in school children with different refractive errors using a novel multispectral refraction topographer.

AIM: To compare relative peripheral refraction (RPR) in Chinese school children with different refractive errors using multispectral refraction topography (MRT). METHODS: A total of 713 eyes of primary school children [172 emmetropia (E), 429 low myopia (LM), 80 moderate myopia (MM), and 32 low hypermetropia (LH)] aged 10 to 13y were analyzed. RPRs were measured using MRT without mydriasis. MRT results showed RPR at 0-15° (RPR 0-15), 15°-30° (RPR 15-30), and 30°-45° (RPR 30-45) annular in the inferior (RPR-I), superior (RPR-S), nasal (RPR-N), and temporal (RPR-T) quadrants. Spherical equivalent (SE) was detected and calculated using an autorefractor. RESULTS: There were significant differences of RPR 15-30 between groups MM [0.02 (-0.12; 0.18)] and LH [-0.13 (-0.36; 0.12)] (P<0.05), MM and E [-0.06 (-0.20; 0.10)] (P<0.05), and LM [-0.02 (-0.15; 0.15)] and E (P<0.05). There were also significant differences of RPR 30-45 between groups MM [0.45 (0.18; 0.74)] and E [0.29 (-0.09; 0.67)] (P<0.05), and LM [0.44 (0.14; 0.76)] and E (P<0.001). RPR values increased from the hyperopic to medium myopic group in each annular. There were significant differences of RPR-S between groups MM [-0.02 (-0.60; 0.30)] and E [-0.44 (-0.89; -0.04)] (P<0.001), and LM [-0.28 (-0.71; 0.12)] and E (P<0.05). There were also significant differences of RPR-T between groups MM [0.37 (0.21; 0.78)] and LH [0.14 (-0.52; 0.50)] (P<0.05), LM [0.41 (0.06; 0.84)] and LH (P<0.05), and LM and E [0.29 (-0.10; 0.68), P<0.05]. A Spearman's correlation analysis showed a negative correlation between RPR and SE in the 15°-30° (P=0.005), 30°-45° (P<0.05) annular (P=0.002), superior (P<0.001), and temporal (P=0.001) quadrants. CONCLUSION: Without pupil dilation, values for RPR 15-30, 30-45, RPR-S, and T shows significant differences between myopic eyes and emmetropia, and the differences are negatively correlated with SE.

Reduced connexin-43 expression, slow conduction and repolarisation dispersion in a model of hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is an inherited heart muscle disease that is characterised by left ventricular wall thickening, cardiomyocyte disarray and fibrosis, and is associated with arrhythmias, heart failure and sudden death. However, it is unclear to what extent the electrophysiological disturbances that lead to sudden death occur secondary to structural changes in the myocardium or as a result of HCM cardiomyocyte electrophysiology. In this study, we used an induced pluripotent stem cell model of the R403Q variant in myosin heavy chain 7 (MYH7) to study the electrophysiology of HCM cardiomyocytes in electrically coupled syncytia, revealing significant conduction slowing and increased spatial dispersion of repolarisation - both well-established substrates for arrhythmia. Analysis of rhythmonome protein expression in MYH7 R403Q cardiomyocytes showed reduced expression of connexin-43 (also known as GJA1), sodium channels and inward rectifier potassium channels - a three-way hit that reduces electrotonic coupling and slows cardiac conduction. Our data represent a previously unreported, biophysical basis for arrhythmia in HCM that is intrinsic to cardiomyocyte electrophysiology. Later in the progression of the disease, these proarrhythmic phenotypes may be accentuated by myocyte disarray and fibrosis to contribute to sudden death.

Generation of an induced pluripotent stem cell line from a patient with conduction disease and recurrent ventricular fibrillation with a sodium voltage-gated channel alpha subunit 5 (SCN5A) gene c.392 + 3A > G splice-site variant.

Variants in the sodium voltage-gated channel alpha subunit 5 gene (SCN5A) produce variable cardiac phenotypes including Brugada syndrome, conduction disease and cardiomyopathy. These phenotypes can lead to life-threatening arrhythmias, heart failure, and sudden cardiac death. Novel variants in splice-site regions of SCN5A require functional studies to characterise their pathogenicity as they are poorly understood. The generation of an induced pluripotent stem cell line provides a valuable resource to investigate the functional effects of potential splice-disrupting variants in SCN5A.

Efficacy of 0.01% atropine for myopia control in a randomized, placebo-controlled trial depends on baseline electroretinal response.

This study aimed to evaluate the efficacy of 18-month 0.01% atropine in 61 myopic children (aged 7-10) and the relationship with central retinal response (by multifocal electroretinogram [mfERG]) in a double-masked randomized placebo-controlled clinical trial. Global-flash mfERG was measured at baseline, while cycloplegic spherical equivalent refraction (SER) and axial length (AL) were measured at baseline and at 6-month intervals. Annualized change in SER and AL were compared between atropine and control groups, and the relationships with baseline mfERG were evaluated. Changes in SER (-0.70 ± 0.39D vs. -0.66 ± 0.41D, p = 0.63) and AL (0.32 ± 0.16 mm vs. 0.30 ± 0.22 mm, p = 0.52) were similar in atropine and control groups. Interestingly, in the placebo group, mfERG amplitude was negatively correlated with axial elongation (Rp = -0.44, p = 0.03) as in our previous study. However, in the atropine group, an opposite trend was observed that axial elongation was positively correlated with mfERG amplitude (Ra = 0.37, p = 0.04). Annualized myopia progression demonstrated similar opposite effect between atropine and placebo groups but did not reach statistical significance. An ERG screening protocol may be warranted to identify suitable candidates to reduce the likelihood of an unfavorable treatment response by 0.01% atropine.

Delay of cone degeneration in retinitis pigmentosa using a 12-month treatment with Lycium barbarum supplement.

ETHNOPHARMACOLOGICAL RELEVANCE: Lycium barbarum L. (also known as "Goji berry"), a traditional Chinese herbal medicine, has been a common herb in the traditional Chinese pharmacopoeia for centuries. The main active component is the Lycium barbarum polysaccharides and its antioxidative effect has been widely shown to provide neuroprotection to the eye, and it would, therefore, be interesting to determine if Lycium barbarum help delay vision deterioration in patients with retinitis pigmentosa. AIM OF THE STUDY: Cone rescue is a potential method for delaying deterioration of visual function in Retinitis pigmentosa (RP). This study aimed to investigate the treatment effect of Lycium barbarum L. (LB) supplement on retinal functions and structure in RP patients after a 12-month intervention trial. METHODS: The investigation was a double-masked and placebo-controlled clinical study. Each of forty-two RP subjects who completed the 12-month intervention (23 and 19 in the treatment and placebo groups respectively) received a daily supply of LB or placebo granules for oral administration. The primary outcome was change of best corrected visual acuity (VA) (90% and 10% contrast) from the baseline to the end of treatment. The secondary outcomes were sensitivity changes of the central visual field, amplitude of full-field electroretinogram (ffERG) (including scotopic maximal response and photopic cone response), and average macular thickness. RESULTS: The compliance rates for both groups exceeded 80%. There were no deteriorations of either 90% or 10% contrast VA in the LB group compared with the placebo group (p = 0.001). A thinning of macular layer was observed in the placebo group, which was not observed in the LB group (p = 0.008). However, no significant differences were found in the sensitivity of visual field or in any parameters of ffERG between the two groups. No significant adverse effects were reported in the treatment group. CONCLUSIONS: LB supplement provides a neuroprotective effect for the retina and could help delay or minimize cone degeneration in RP. CLASSIFICATIONS: Clinical Studies (1.05). TRIAL REGISTRATION: clinicaltrials.gov Identifier NCT02244996.

Lycium Barbarum Polysaccharides Rescue Neurodegeneration in an Acute Ocular Hypertension Rat Model Under Pre- and Posttreatment Conditions.

Purpose: To investigate the posttreatment neuronal rescue effects of Lycium barbarum polysaccharides (LBP) in an acute ocular hypertensive (AOH) model. Methods: Intraocular pressure (IOP) was elevated manometrically to 80 mm Hg (AOH) or 15 mm Hg (sham) for 120 minutes in adult Sprague-Dawley rats. Five experimental groups were considered: Three AOH groups were pretreated with PBS (vehicle) (n = 9), LBP 1 mg/kg (n = 8), or 10 mg/kg (n = 13), and one AOH group was posttreated with LBP 10 mg/kg (n = 8), once daily. The sham cannulation group (n = 5) received no treatment. Pretreatments commenced 7 days before and posttreatment 6 hours after AOH, and continued up through postcannulation day 28. All the animals underwent optical coherence tomography and electroretinogram measurements at baseline and postcannulation days 10 and 28. The ganglion cell layer (GCL) densities were quantified at day 28. Results: Both inner retinal layer thickness (IRLT) and positive scotopic threshold response (pSTR) underwent significant reduction (≥50% of thickness and amplitude) in the vehicle group (P < 0.05). Pretreatment with LBP 1 and 10 mg/kg retained 77 ± 11% and 89 ± 8% of baseline IRLT, respectively, and preserved pSTR functions. The posttreatment group showed a significant reduction in IRLT (-35 ± 8%, P < 0.001) and pSTR (∼48% of baseline, P < 0.001) on day 10. By day 28, there was an improvement in functional pSTR (∼72% of baseline, P > 0.05) with no significant further thinning (-40 ± 8%, P = 0.15) relative to day 10. GCL density was reduced in vehicle control (P = 0.0001), but did not differ between sham and pre- and posttreated AOH groups. Conclusions: The rescue effect of LBP posttreatment was observed later, which arrested the secondary degeneration and improved the retinal function.

Subclinical Decrease in Central Inner Retinal Activity Is Associated With Myopia Development in Children.

Purpose: To investigate the characteristics of retinal electrophysiological activity in relation to early myopia development in children. Methods: Fifty-six children aged 6 to 9 years with emmetropic refractive error (defined as ≥ -0.5 diopter [D] and ≤ +0.5 D) were recruited. Cycloplegic refraction, axial length, and global flash multifocal electroretinogram (MOFO mfERG) at 49% and 96% contrast levels were recorded in all children at their first visit. The refraction and axial length measurements were repeated after 1 year. The amplitudes and implicit times of the direct component (DC) and the induced component (IC) of the MOFO mfERG obtained at the initial visit were analyzed. Correlations between the MOFO mfERG parameters and changes in refractive error and axial length were investigated. Results: The mean spherical equivalent refractive error and axial length of the eyes of the children at the first visit were +0.19 ± 0.33 D and 23.14 ± 0.6 mm, respectively. After 1 year, the mean refractive error increased by -0.55 ± 0.53 D, whereas axial length increased by 0.37 ± 0.22 mm. The changes in refractive error and axial length were significantly correlated with the central IC amplitudes at 49% contrast level measured at the initial visit (ρ = 0.46, P < 0.001 and ρ = -0.34, P = 0.01, respectively). Conclusions: The prospective changes we have shown are believed to derive from central inner retina. These changes appear to precede myopia and could be a potential reference for juvenile myopia development.

Helpfulness of nursing actions to suddenly bereaved family members in an accident and emergency setting in Hong Kong.

BACKGROUND: The sudden death of a family member is always traumatic to the family. Nursing actions such as providing comfort measures and providing an opportunity to view the deceased were consistently perceived as helpful by the suddenly bereaved. Little is known about the perception of bereaved family members in Hong Kong concerning the care they received in accident and emergency (A & E) departments. This study serves to identify actions, which were perceived as helpful in A & E setting in Hong Kong. AIM: To gain knowledge about what nursing actions bereaved family members in Hong Kong perceived as helpful. METHOD: This study was exploratory and descriptive in nature, and used a quantitative approach. Data were collected through structured telephone interviews using a modified Tye's questionnaire. RESULTS: Seventy-six bereaved subjects were recruited in an A & E department in Hong Kong. The subjects perceived written information, opportunity to view the deceased, and respecting individual customs and religious procedures as most helpful and conversely, offering sedation, discouraging viewing of the body, and providing comfort measures as most unhelpful. No statistically significant differences among the overall mean of helpful nursing actions according to the subjects' age, gender, education level, family income and religions were found while using Mann-Whitney's U and Kruskal-Wallis' tests. Significant correlations between some actions and the respondents' age, family income and educational level were found. CONCLUSION: Accident and emergency nurses have unique role in offering helpful actions to support suddenly bereaved family members.