Influence of anterior chamber depth and vault on anterior chamber angle morphology after phakic posterior chamber intraocular lens implantation.

PURPOSE: This study aims to investigate the influence of anterior chamber depth (ACD) and vault on the anterior chamber angle (ACA) morphology in myopic individuals implanted with posterior chamber phakic intraocular lenses. METHODS: This retrospective case series involved 231 eyes receiving a 13.2-mm implantable collamer lens (ICL). Preoperative anterior chamber anatomy was assessed using anterior segment optical coherence tomography (AS-OCT) and optical tomography, while postoperative evaluation employed AS-OCT. ACA morphology was characterized pre- and postoperatively through trabecular iris angle (TIA750), ACA distance opening (AOD750) and trabecular iris space area (TISA750). The influence of ACD and vault was examined by categorizing the sample into ACD (shallow, average and deep) and vault (low, optimal and high) groups. RESULTS: Preoperative ACA morphology varied based on ACD, with shallower ACDs exhibiting narrower TIA750, smaller AOD750 and TISA750. ICL implantation induced greater ACA narrowing more in the deep ACD group (TIA750 = 20.1 degrees; AOD750 = 0.82 mm and TISA750 = 0.44 mm2) compared to the shallow ACD group (TIA750 = 15.2 degrees; AOD750 = 0.44 mm and TISA750 = 0.21 mm2). Postoperatively, deeper ACDs showed larger ACAs. Increasing vault magnitude led to increased ACA narrowing, with the low vault group exhibiting smaller closure (TIA750 = 14.3 degrees; AOD750 = 0.56 mm and TISA750 = 0.29 mm2) compared to the high vault group (TIA750 = 20.8 degrees; AOD750 = 0.73 mm and TISA750 = 0.36 mm2). The magnitude of ACA narrowing associated with the vault had a consistent effect across different ACD groups. CONCLUSIONS: Posterior chamber intraocular lens implantation results in ACA narrowing, the extent of which is contingent upon preoperative anterior chamber and ACA morphology, with additional influence from vault magnitude.

Discussion on Secure Standard Network of Sensors Powered by Microbial Fuel Cells.

Everyday tasks use sensors to monitor and provide information about processes in different scenarios, such as monitoring devices in manufacturing or homes. Sensors need to communicate, with or without wires, while providing secure information. Power can be derived from various energy sources, such as batteries, electrical power grids, and energy harvesting. Energy harvesting is a promising way to provide a sustainable and renewable source to power sensors by scavenging and converting energy from ambient energy sources. However, low energy is harvested through these methods. Therefore, it is becoming a challenge to design and deploy wireless sensor networks while ensuring the sensors have enough power to perform their tasks and communicate with each other through careful management and optimization, matching energy supply with demand. For this reason, data cryptography and authentication are needed to protect sensor communication. This paper studies how energy harvested with microbial fuel cells can be employed in algorithms used in data protection during sensor communication.

Expression of symptoms elicited by a hammerhead viroid through RNA silencing is related to population bottlenecks in the infected host.

Chlorosis is frequently incited by viroids, small nonprotein-coding, circular RNAs replicating in nuclei (family Pospiviroidae) or chloroplasts (family Avsunviroidae). Here, we investigated how chrysanthemum chlorotic mottle viroid (CChMVd, Avsunviroidae) colonizes, evolves and initiates disease. Progeny variants of natural and mutated CChMVd sequence variants inoculated in chrysanthemum plants were characterized, and plant responses were assessed by molecular assays. We showed that: chlorotic mottle induced by CChMVd reflects the spatial distribution and evolutionary behaviour in the infected host of pathogenic (containing a UUUC tetranucleotide) and nonpathogenic (lacking such a pathogenic determinant) variants; and RNA silencing is involved in the initiation of the chlorosis in symptomatic leaf sectors through a viroid-derived small RNA containing the pathogenic determinant that directs AGO1-mediated cleavage of the mRNA encoding the chloroplastic transketolase. This study provides the first evidence that colonization of leaf tissues by CChMVd is characterized by segregating variant populations differing in pathogenicity and with the ability to colonize leaf sectors (bottlenecks) and exclude other variants (superinfection exclusion). Importantly, no specific pathogenic viroid variants were found in the chlorotic spots caused by chrysanthemum stunt viroid (Pospiviroidae), thus establishing a clear distinction on how members of the two viroid families trigger chlorosis in the same host.

Prediction model of the horizontal trabecular iris angle after phakic posterior chamber implantable intraocular lens surgery.

PURPOSE: To determine the predictors of the postoperative horizontal trabecular iris angle (TIA 750 ) after phakic posterior chamber implantable intraocular lens (IOL) surgery. SETTING: Ophthalmology Clinic Vista Sánchez Trancón, Badajoz, Spain. DESIGN: Retrospective case series. METHODS: 330 eyes implanted with spherical/toric implantable collamer lens (ICL) were included in this study. From 230 eyes implanted with 13.2 mm ICL, these were divided in modeling (n = 180) and evaluation group (n = 50). Two groups implanted with 12.6 mm and 13.7 mm (n = 50 each) were also used as evaluation. Anterior-segment optical coherence tomography was used preoperatively to perform anterior chamber biometry (angle-to-angle [ATA] distance, crystalline lens rise, anterior chamber depth [ACD], cornea sagittal depth, pupil diameter, nasal/temporal TIA 750 ); postoperatively for measuring the vault, pupil diameter and nasal/temporal TIA 750 . Corneal curvature and horizontal visible iris diameter were measured using optical tomography. Bivariate correlation analysis was used to determine associations between preoperative and postoperative horizontal TIA 750 with anterior chamber biometry, ICL-related parameters and age. Finally, a multivariate linear regression model was constructed for predicting the postoperative TIA 750 . RESULTS: Horizontal TIA 750 reduced from 42.9 ± 8.0 degrees preoperatively to 24.4 ± 5.6 degrees postoperatively. Postoperative TIA 750 was positively correlated with the preoperative TIA 750 , cornea sagittal depth and ACD, and negatively associated with the vault. The main predictors of the postoperative TIA 750 were the preoperative parameters, TIA 750 , ICLsize - ATA and pupil diameter (adjusted- R2 = 0.39). The limits of agreement between predicted and real TIA 750 were close to ±10 degrees. CONCLUSIONS: Implantation of a phakic posterior chamber implantable IOL leads to a reduction in TIA 750 and the main factors contributing for this are the preoperative TIA 750 aperture and the vault.

Repeatability and agreement of swept-source optical coherence tomography and partial coherence interferometry biometers in myopes.

CLINICAL RELEVANCE: Biometric measurements in the context of myopia are fundamental to detect eyes at risk of developing myopia and during the follow-up of patients with myopia control treatment. Thus, the accuracy of biometers has high clinical relevance. BACKGROUND: The Myopia Master is a new biometer based on partial coherence interferometry especially dedicated to the follow-up of myopic patients. This study aims to assess the repeatability of the Myopia Master and evaluate its agreement with a swept-source optical coherence interferometry biometer (IOL Master 700). METHODS: This cross-sectional prospective study assessed the biometric parameters of two groups of myopes (age range: 8-16 years old), spectacle corrected (n = 60) and orthokeratology contact lens wearers (n = 60). One senior optometrist performed two consecutive measurements per instrument, which included axial length, mean keratometry and horizontal visible iris diameter (HVID). The repeatability of each device and the agreement between devices were assessed by the dispersion of the measurement differences, for AL, mean keratometry, corneal astigmatism and HVID. RESULTS: The two biometers measured approximately the same value in both measurements. Test-retest repeatability tended to be lower than clinical significant thresholds, in particular, for AL and mean keratometry. Corneal-related parameters tended to have lower repeatability in the orthokeratology group, especially mean keratometry. The agreement between instruments revealed statistically significant differences between devices with the SS-OCT measuring longer eyes, steeper corneas and larger HVID. CONCLUSIONS: In a paediatric population, the Myopia Master showed clinically acceptable repeatability levels, but the IOL Master 700 demonstrated superior repeatability. Eyes treated with orthokeratology may compromise the repeatability of the corneal-related parameters. The Myopia Master and the IOL Master 700 are repeatable devices appropriate for monitoring myopia progression, but the differences observed do not allow their use interchangeably.

Role of RNA silencing in plant-viroid interactions and in viroid pathogenesis.

Viroids are small, single-stranded, non-protein coding and circular RNAs able to infect host plants in the absence of any helper virus. They may elicit symptoms in their hosts, but the underlying molecular pathways are only partially known. Here we address the role of post-transcriptional RNA silencing in plant-viroid-interplay, with major emphasis on the involvement of this sequence-specific RNA degradation mechanism in both plant antiviroid defence and viroid pathogenesis. This review is a tribute to the memory of Dr. Ricardo Flores, who largely contributed to elucidate this and other molecular mechanisms involved in plant-viroid interactions.

Vault differences in eyes implanted with spherical and toric implantable collamer lenses: an inter-eye analysis.

PURPOSE: To determine the influence of implantable collamer lenses (ICL) geometry, i.e. spherical and toric on the vault, and report the refractive and visual outcomes of patients bilaterally implanted with the two ICL geometries. METHODS: This retrospective case series analysed 41 patients implanted with a spherical ICL (sICL) in one eye and an equal sized toric ICL (tICL) in the fellow eye. The anatomical and ICL-related parameters were assessed using anterior-segment optical coherence tomography (AS-OCT Visante, Zeiss Meditec AG) and optical tomography (Pentacam, OCULUS). The influence of the anatomical and ICL-related parameters on the vault was determined using generalised estimating equations (GEE) to incorporate inter-eye correlations. RESULTS: Postoperative spherical equivalent was within ± 0.50D in 66% and 83% of the eyes, respectively implanted with sICL and tICL. The efficacy index in the sICL group was 1.06 and 1.14 in the tICL group. The mean inter-eye vault difference was -1.46 µm, anatomical and ICL-related parameters showed similar associations with the vault for sICL and tICL. The GEE identified the ICL size minus the anterior chamber width, the ICL spherical power and ICL central thickness as significant factors influencing the vault. CONCLUSIONS: Spherical and toric ICL showed good efficacy for the correction of myopia and astigmatism. Patients implanted bilaterally with sICL and tICL tend to present similar vaults. The vault produced by both types of ICL was mainly regulated by the oversizing of the ICL. This suggests that the ICL geometry (spherical vs toric) is a factor with limited influence on the vault, thus the sizing method of a sICL and tICL should be similar.

A scenario for the emergence of protoviroids in the RNA world and for their further evolution into viroids and viroid-like RNAs by modular recombinations and mutations.

Viroids are tiny, circular, and noncoding RNAs that are able to replicate and systemically infect plants. The smallest known pathogens, viroids have been proposed to represent survivors from the RNA world that likely preceded the cellular world currently dominating life on the earth. Although the small, circular, and compact nature of viroid genomes, some of which are also endowed with catalytic activity mediated by hammerhead ribozymes, support this proposal, the lack of feasible evolutionary routes and the identification of hammerhead ribozymes in a large number of DNA genomes of organisms along the tree of life have led some to question such a proposal. Here, we reassess the origin and subsequent evolution of viroids by complementing phylogenetic reconstructions with molecular data, including the primary and higher-order structure of the genomic RNAs, their replication, and recombination mechanisms and selected biological information. Features of some viroid-like RNAs found in plants, animals, and possibly fungi are also considered. The resulting evolutionary scenario supports the emergence of protoviroids in the RNA world, mainly as replicative modules, followed by a further increase in genome complexity based on module/domain shuffling and combination and mutation. Such a modular evolutionary scenario would have facilitated the inclusion in the protoviroid genomes of complex RNA structures (or coding sequences, as in the case of hepatitis delta virus and delta-like agents), likely needed for their adaptation from the RNA world to a life based on cells, thus generating the ancestors of current infectious viroids and viroid-like RNAs. Other noninfectious viroid-like RNAs, such as retroviroid-like RNA elements and retrozymes, could also be derived from protoviroids if their reverse transcription and integration into viral or eukaryotic DNA, respectively, are considered as a possible key step in their evolution. Comparison of evidence supporting a general and modular evolutionary model for viroids and viroid-like RNAs with that favoring alternative scenarios provides reasonable reasons to keep alive the hypothesis that these small RNA pathogens may be relics of a precellular world.

Gel Blot Hybridization for Viroids.

Northern blot analysis reveals information about RNA identity, size, and abundance. This technique has become an essential tool for the knowledge developed about viroids and also an excellent method for viroid detection. Here we describe the methodology of a Northern blot based in polyacrylamide gel electrophoresis under denaturing conditions, hybridized with a viroid full-length riboprobe labeled with chemiluminescence. Viroid detection with this approach entails positive signals, specific migration, and the differentiation of their circular and linear forms.

Biometric and ICL-related risk factors associated to sub-optimal vaults in eyes implanted with implantable collamer lenses.

BACKGROUND: To identify biometric and implantable collamer lens (ICL)-related risk factors associated with sub-optimal postoperative vault in eyes implanted with phakic ICL. METHODS: This study reports a retrospective case series of the first operated eye in 360 patients implanted with myopic spherical or toric ICL. Preoperatively, white-to-white (WTW), central keratometry (Kc) and central corneal thickness (CCT) were measured using the Pentacam. Anterior-segment optical coherence tomography (AS-OCT, Visante) was applied preoperatively for measuring the horizontal anterior-chamber angle-to-angle distance (ATA), internal anterior chamber depth (ACD), crystalline lens rise (CLR), anterior-chamber angle (ACA) and postoperatively the vault. Eyes were divided into three vault groups: low (LVG: ≤ 250 µm), optimal (OVG: > 250 and < 1000 µm) and high (HVG: ≥ 1000 µm). Multinomial logistic regression (MLR) was used to find the sub-optimal vault predictors. RESULTS: MLR showed that CLR, ICL size minus the ATA (ICL size-ATA), age, ICL spherical equivalent (ICLSE) and ICL size as contributing factors for sub-optimal vaults (pseudo-R2 = 0.40). Increased CLR (OR: 1.01, CI: 1.00-1.01) and less myopic ICLSE (OR: 1.22, CI: 1.07-1.40) were risk factors for low vaults. Larger ICL size-ATA (OR: 41.29, CI: 10.57-161.22) and the 13.7 mm ICL (OR: 7.08, CI: 3.16-15.89) were risk factors for high vaults, whereas less myopic ICLSE (OR: 0.85, CI: 0.76-0.95) and older age (OR: 0.92, CI: 0.88-0.98) were protective factors. CONCLUSION: High CLR and low ICLSE were the major risk factors in eyes presenting low vaults. In the opposite direction, ICL size-ATA was the major contributor for high vaults. This relationship was more critical in higher myopic ICLSE, younger eyes and when 13.7 mm ICL were used. The findings show that factors influencing the vault have differentiated weight of influence depending on the type of vault (low, optimal or high).

Association between Clinical Vision Measures and Visual Perception and Soccer Referees' On-field Performance.

SIGNIFICANCE: The decisions taken by soccer officials are critically important to game management. Understanding the underlying processes that mediate expert performance in soccer refereeing may lead to a better standard of officiating. Vision is the dominant source of incoming information upon which officials rely to make their on-field decisions. PURPOSE: We tested the hypothesis that performance on generic tests of vision and visual perception predicts domain-specific performance in elite-level soccer referees (R) and assistant referees (AR). METHODS: We assessed the vision of R and AR who officiate at the highest level in Portugal. To be eligible for inclusion, R and AR had to have officiated for at least two consecutive seasons across the 2014/2015, 2015/2016, and 2016/2017 seasons. A single, rank-order list of the performance of eligible officials was created based on the rank-order list for each season that was made by the Portuguese Soccer Federation. Clinical vision measures included visual acuity and stereoacuity, and visual perception measures were gathered using the Test of Visual Perceptual Skills, Third Edition. RESULTS: A total of 59 officials participated (21 R, 38 AR), 17 of whom officiated at the international level. The R and AR groups did not differ in vision or visual perception measures. We found that better stereoacuity (P < .001) and visual memory (P = .001) are associated with a higher rank order of on-field performance after adjusting for the age, experience, the national/international status, and the regional affiliation of the officials. Together, these two measures explain 22% of the variance in rank-order performance. CONCLUSIONS: This is the first study to show a link between the vision of officials and their on-field performance. The origin and significance of these findings remain to be established, and further work is required to establish whether they are component skills in the domain of soccer refereeing.

Degradome Analysis of Tomato and Nicotiana benthamiana Plants Infected with Potato Spindle Tuber Viroid.

Viroids are infectious non-coding RNAs that infect plants. During infection, viroid RNAs are targeted by Dicer-like proteins, generating viroid-derived small RNAs (vd-sRNAs) that can guide the sequence specific cleavage of cognate host mRNAs via an RNA silencing mechanism. To assess the involvement of these pathways in pathogenesis associated with nuclear-replicating viroids, high-throughput sequencing of sRNAs and degradome analysis were carried out on tomato and Nicotiana benthamiana plants infected by potato spindle tuber viroid (PSTVd). Both hosts develop similar stunting and leaf curling symptoms when infected by PSTVd, thus allowing comparative analyses. About one hundred tomato mRNAs potentially targeted for degradation by vd-sRNAs were initially identified. However, data from biological replicates and comparisons between mock and infected samples reduced the number of bona fide targets-i.e., those identified with high confidence in two infected biological replicates but not in the mock controls-to only eight mRNAs that encode proteins involved in development, transcription or defense. Somewhat surprisingly, results of RT-qPCR assays revealed that the accumulation of only four of these mRNAs was inhibited in the PSTVd-infected tomato. When these analyses were extended to mock inoculated and PSTVd-infected N. benthamiana plants, a completely different set of potential mRNA targets was identified. The failure to identify homologous mRNA(s) targeted by PSTVd-sRNA suggests that different pathways could be involved in the elicitation of similar symptoms in these two species. Moreover, no significant modifications in the accumulation of miRNAs and in the cleavage of their targeted mRNAs were detected in the infected tomato plants with respect to the mock controls. Taken together, these data suggest that stunting and leaf curling symptoms induced by PSTVd are elicited by a complex plant response involving multiple mechanisms, with RNA silencing being only one of the possible components.

Superparamagnetic Nanoparticles with Efficient Near-Infrared Photothermal Effect at the Second Biological Window.

Superparamagnetic nanoparticles (iron oxide nanoparticles-IONs) are suitable for hyperthermia after irradiating with radiofrequency radiation. Concerning the suitability for laser ablation, IONs present a low molar absorption coefficient in the near-infrared region close to 800 nm. For this reason, they are combined with other photothermal agents into a hybrid composite. Here, we show that IONs absorb and convert into heat the infrared radiation characteristic of the so-called second-biological window (1000-1350 nm) and, in consequence, they can be used for thermal ablation in such wavelengths. To the known excellent water solubility, colloidal stability and biocompatibility exhibited by IONs, an outstanding photothermal performance must be added. For instance, a temperature increase of 36 °C was obtained after irradiating at 8.7 W cm-2 for 10 min a suspension of IONs at iron concentration of 255 mg L-1. The photothermal conversion efficiency was ~72%. Furthermore, IONs showed high thermogenic stability during the whole process of heating/cooling. To sum up, while the use of IONs in the first bio-window (700-950 nm) presents some concerns, they appear to be good photothermal agents in the second biological window.

Inter-Eye Vault Differences of Implantable Collamer Lens Measured Using Anterior Segment Optical Coherence Tomography.

PURPOSE: The distance between an implantable collamer lens (ICL) and the crystalline lens, namely vault, is a space regulated by the interaction of the ICL and the anatomical structures of the eye. This study analysed the differences in vault size between fellow eyes with similar anterior segment biometry. PATIENTS AND METHODS: A retrospective case series analysed 109 cases of patients bilaterally implanted with EVO-V4c. Patients were analysed pre- and postoperatively using anterior segment optical coherence tomography. The range of vault inter-eye differences was defined as the 95% confidence interval of the differences. Bivariate correlation was applied to seek for associations between vault inter-eye differences with biometric and lens parameters (angle-to-angle, anterior chamber depth, crystalline lens rise, central corneal thickness, central keratometry, ICL spherical equivalent, horizontal compression, postoperative pupil diameter and vault). RESULTS: Mean vault inter-eye differences were similar between fellow eyes (26.0 ± 122.5 µm). The 95% confidence interval range of the differences was ±240.1 µm, nearly 50% of the cases presented vault inter-eye differences higher than 100 µm. The vault of the first operated eye explained 81% of the variance in the second eye vault. Vault inter-eye differences were positively correlated with the level of horizontal compression and with vault magnitude. CONCLUSION: Vaults measured in fellow eyes may present considerable differences, which can reach 25% of the common vault range. This reflects some degree of baseline variability in the vault. Clinically, these differences assume special relevance in cases where low or high vaults are expected.

Visual Status in a Portuguese Population with Intellectual Disability.

BACKGROUND: Neurosensory deprivation associated with vision is a well-known fact in people with intellectual disability (ID). This work aims to report the visual status of a population with ID in Portugal. METHODS: A vision screening protocol was conducted during two Special Olympics events. The vision protocol included personal medical history, ocular health evaluation, and clinical measures, such as visual acuity (VA), binocular vision, colour vision, refractive error, and intraocular pressure. This protocol was administered to 134 subjects. RESULTS: Half of the subjects reported that they had never attended or they did not remember having attended a previous eye exam. Additionally, 10% of them had not attended an eye exam in the immediate past three years. Half the subjects failed the VA test and 13% presented moderate Visual Impairment (VI) (VA worse than 0.5 logMAR in the best eye). Manifest ocular deviation was found in 25% of the subjects and the most common ocular health dysfunction conditions were conjunctiva hyperaemia, meibomian gland dysfunction, and lens anomalies. Refractive error correction allowed a reduction in the level of moderate VI to 3.7%. CONCLUSIONS: The population analysed showed a poor eye care attendance rate and vision-related conditions are in agreement with previous reports. The development of national strategies to promote the awareness for routine eye care in people with ID and improving accessibility to eye care services may mitigate many of the most prevalent conditions encountered.

Revisiting the cysteine-rich proteins encoded in the 3'-proximal open reading frame of the positive-sense single-stranded RNA of some monopartite filamentous plant viruses: functional dissection of p15 from grapevine virus B.

A reexamination of proteins with conserved cysteines and basic amino acids encoded by the 3'-proximal gene of the positive-sense single-stranded RNA of some monopartite filamentous plant viruses has been carried out. The cysteines are involved in a putative Zn-finger domain, which, together with the basic amino acids, form part of the nuclear or nucleolar localization signals. An in-depth study of one of these proteins, p15 from grapevine B virus (GVB), has shown: (i) a three-dimensional structure with four α-helices predicted by two independent in silico approaches, (ii) the nucleolus as the main accumulation site by applying confocal laser microscopy to a fusion between p15 and the green fluorescent protein, (iii) the involvement of the basic amino acids and the putative Zn-finger domain, mapping at the N-terminal region of p15, in the nucleolar localization signal, as revealed by the effect of six alanine substitution mutations, (iv) the p15 suppressor function of sense-mediated RNA silencing as revealed by agroinfiltration in a transgenic line of Nicotiana benthamiana, and (v) the enhancer activity of p15 on viral pathogenicity in N. benthamiana when expressed from a potato virus X vector. In addition, we elaborate on an evolutionary scenario for these filamentous viruses, invoking takeover by a common ancestor(s) of viral or host genes coding for those cysteine-rich proteins, followed by divergence, which would also explain why they are encoded in the 3'-proximal gene of the genomic single-stranded viral RNA.

Viroid pathogenesis: a critical appraisal of the role of RNA silencing in triggering the initial molecular lesion.

The initial molecular lesions through which viroids, satellite RNAs and viruses trigger signal cascades resulting in plant diseases are hotly debated. Since viroids are circular non-protein-coding RNAs of ∼250-430 nucleotides, they appear very convenient to address this issue. Viroids are targeted by their host RNA silencing defense, generating viroid-derived small RNAs (vd-sRNAs) that are presumed to direct Argonaute (AGO) proteins to inactivate messenger RNAs, thus initiating disease. Here, we review the existing evidence. Viroid-induced symptoms reveal a distinction. Those attributed to vd-sRNAs from potato spindle tuber viroid and members of the family Pospiviroidae (replicating in the nucleus) are late, non-specific and systemic. In contrast, those attributed to vd-sRNAs from peach latent mosaic viroid (PLMVd) and other members of the family Avsunviroidae (replicating in plastids) are early, specific and local. Remarkably, leaf sectors expressing different PLMVd-induced chloroses accumulate viroid variants with specific pathogenic determinants. Some vd-sRNAs containing such determinant guide AGO1-mediated cleavage of mRNAs that code for proteins regulating chloroplast biogenesis/development. Therefore, the initial lesions and the expected phenotypes are connected by short signal cascades, hence supporting a cause-effect relationship. Intriguingly, one virus satellite RNA initiates disease through a similar mechanism, whereas in the Pospiviroidae and in plant viruses the situation remains uncertain.

Determining vault size in implantable collamer lenses: preoperative anatomy and lens parameters.

PURPOSE: To determine patient preoperative anatomical features and the parameters of implantable collamer lenses (ICLs) relevant in explaining vault variability. SETTING: Ophthalmology Clinic Vista Sánchez Trancón, Badajoz, Spain. DESIGN: Retrospective case series. METHODS: This study comprised 360 eyes of 360 patients implanted with myopic or toric ICLs. Pentacam imaging was used for assessing white-to-white (WTW) diameter, central keratometry, and central corneal thickness. Anterior-segment optical coherence tomography was used to measure the horizontal anterior chamber angle distance (ATA), internal anterior chamber (ACQ), crystalline lens rise (CLR), anterior chamber angle (ACA), and vault. The sample was divided according to the implanted lens size (12.6 mm, 13.2 mm, and 13.7 mm). Vault predictors were identified from the variables above using multivariate regression analysis. RESULTS: The groups showed significant statistical differences for WTW, ATA, ACQ, ACA, and vault (P < .007 for all). In general, bigger lenses were implanted in eyes with larger transverse sizes (WTW and ATA) and deeper ACQ. Also, larger ICL diameters were associated with higher vaults. Multivariate regression analysis identified the lens size (13.2 mm as reference; 12.6 mm: ß [standardized coefficients] = -0.33; 13.7 mm: ß = 0.42), ATA (ß = -0.42), and CLR (ß = -0.25), ICL spherical equivalent (ß = -0.22) and patient age (ß = -0.12) as predictors of the vault size (adjusted-R = 0.34 P < .001). CONCLUSIONS: The multivariate model explained 34% of vault variability. The predictors indicated the presence of different mechanisms regulating the vault. These involved the difference between the transverse size of the eye and the ICL, the crystalline lens protrusion, and the ICL properties, such as power and size.

How sequence variants of a plastid-replicating viroid with one single nucleotide change initiate disease in its natural host.

Understanding how viruses and subviral agents initiate disease is central to plant pathology. Whether RNA silencing mediates the primary lesion triggered by viroids (small non-protein-coding RNAs), or just intermediate-late steps of a signaling cascade, remains unsolved. While most variants of the plastid-replicating peach latent mosaic viroid (PLMVd) are asymptomatic, some incite peach mosaics or albinism (peach calico, PC). We have previously shown that two 21-nt small RNAs (PLMVd-sRNAs) containing a 12-13-nt PC-associated insertion guide cleavage, via RNA silencing, of the mRNA encoding a heat-shock protein involved in chloroplast biogenesis. To gain evidence supporting that such event is the initial lesion, and more specifically, that different chloroses have different primary causes, here we focused on a PLMVd-induced peach yellow mosaic (PYM) expressed in leaf sectors interspersed with others green. First, sequencing PLMVd-cDNAs from both sectors and bioassays mapped the PYM determinant at one nucleotide, a notion further sustained by the phenotype incited by other natural and artificial PLMVd variants. And second, sRNA deep-sequencing and RNA ligase-mediated RACE identified one PLMVd-sRNA with the PYM-associated change that guides cleavage, as predicted by RNA silencing, of the mRNA encoding a thylakoid translocase subunit required for chloroplast development. RT-qPCR showed lower accumulation of this mRNA in PYM-expressing tissues. Remarkably, PLMVd-sRNAs triggering PYM and PC have 5'-terminal Us, involving Argonaute 1 in what likely are the initial alterations eliciting distinct chloroses.