Asymmetric Intrastromal Corneal Ring Segments with Progressive Base Width and Thickness for Keratoconus: Evaluation of Efficacy and Analysis of Epithelial Remodeling.

Purpose: The aim of this study is to describe visual outcomes and epithelial remodeling following the implantation of asymmetric intracorneal ring segments (ICRSs) of variable thickness and base width for the management of duck-type keratoconus. Methods: A prospective observational study of patients with duck-type keratoconus was conducted. All patients received one ICRS AJL PRO + implant (AJL Ophthalmic). We analyzed demographic and clinical data, anterior segment optical coherence tomography (AS-OCT) data and Scheimpflug camera images obtained with a Placido disc MS-39 (CSO, Firenze, Italy) one and six months after surgery to determine keratometric and aberrometric outcomes and epithelial remodeling. Results: We studied 33 keratoconic eyes. ICRS implantation significantly improved both corrected distance visual acuity (CDVA) and uncorrected distance visual acuity at six months, as assessed with the logMAR (minimum angle of resolution) system, from 0.32 ± 0.19 to 0.12 ± 0.12 (p < 0.001) and from 0.75 ± 0.38 to 0.37 ± 0.24 (p < 0.001), respectively. Overall, 87% of implanted eyes gained ≥ 1 line of CDVA, and 3% of patients (n = 1) lost one line of CDVA; 55% of eyes attained a manifest refraction spherical equivalent between +1.50 and -1.50 D. Epithelial remodeling was greater at the wider and thicker end (+11.33 µm ± 12.95; p < 0.001 relative to the initial value) than at the narrower and thinner end (+2.24 µm ± 5.67; p = 0.01). Coma aberration was significantly reduced from 1.62 ± 0.81 µm to 0.99 ± 0.59 µm (p < 0.001). Conclusions: AJL-PRO + ICRS implantation for duck-type keratoconus improves refractive, topographic, aberrometric and visual parameters and induces progressive epithelial thickening along the segment.

Dynamic imaging of cell wall polysaccharides by metabolic click-mediated labeling of pectins in living elongating cells.

Protein tracking in living plant cells has become routine with the emergence of reporter genes encoding fluorescent tags. Unfortunately, this imaging strategy is not applicable to glycans because they are not directly encoded by the genome. Indeed, complex glycans result from sequential additions and/or removals of monosaccharides by the glycosyltransferases and glycosidases of the cell's biosynthetic machinery. Currently, the imaging of cell wall polymers mainly relies on the use of antibodies or dyes that exhibit variable specificities. However, as immunolocalization typically requires sample fixation, it does not provide access to the dynamics of living cells. The development of click chemistry in plant cell wall biology offers an alternative for live-cell labeling. It consists of the incorporation of a carbohydrate containing a bio-orthogonal chemical reporter into the target polysaccharide using the endogenous biosynthetic machinery of the cell. Once synthesized and deposited in the cell wall, the polysaccharide containing the analog monosaccharide is covalently coupled to an exogenous fluorescent probe. Here, we developed a metabolic click labeling approach which allows the imaging of cell wall polysaccharides in living and elongating cells without affecting cell viability. The protocol was established using the pollen tube, a useful model to follow cell wall dynamics due to its fast and tip-polarized growth, but was also successfully tested on Arabidopsis root cells and root hairs. This method offers the possibility of imaging metabolically incorporated sugars of viable and elongating cells, allowing the study of the long-term dynamics of labeled extracellular polysaccharides.

Adcyap1 polymorphism covaries with breeding latitude in a Nearctic migratory songbird, the Wilson's warbler (Cardellina pusilla).

Understanding the genetic background of complex behavioral traits, showing multigenic control and extensive environmental effects, is a challenging task. Among such traits, migration is known to show a large additive genetic component. Yet, the identification of specific genes or gene regions explaining phenotypic variance in migratory behavior has received less attention. Migration ultimately depends on seasonal cycles, and polymorphism at phenological candidate genes may underlie variation in timing of migration or other aspects of migratory behavior. In this study of a Nearctic-Neotropical migratory songbird, the Wilson's warbler (Cardellina pusilla), we investigated the association between polymorphism at two phenological candidate genes, Clock and Adcyap1, and two aspects of the migratory phenotype, timing of spring migration through a stopover site and inferred latitude of the breeding destination. The breeding destination of migrating individuals was identified using feather deuterium ratio (δ (2)H), which reliably reflects breeding latitude throughout the species' western breeding range. Ninety-eight percent of the individuals were homozygous at Clock, and the rare heterozygotes did not deviate from homozygous migration phenology. Adcyap1 was highly polymorphic, and allele size was not significantly associated with migration date. However, Adcyap1 allele size significantly positively predicted the inferred breeding latitude of males but not of females. Moreover, we found a strong positive association between inferred breeding latitude and Adcyap1 allele size in long-distance migrating birds from the northern sector of the breeding range (western Canada), while this was not the case in short-distance migrating birds from the southern sector of the breeding range (coastal California). Our findings support previous evidence for a role of Adcyap1 in shaping the avian migratory phenotype, while highlighting that patterns of phenological candidate gene-phenotype associations may be complex, significantly varying between geographically distinct populations and even between the sexes.

Testosterone treatment diminishes sickness behavior in male songbirds.

Males of many vertebrate species are typically more prone to disease and infection than female conspecifics, and this sexual difference is partially influenced by the immunosuppressive properties of testosterone (T) in males. T-induced immunosuppression has traditionally been viewed as a pleiotropic handicap, rather than an adaptation. Recently, it has been hypothesized that suppression of sickness behavior, or the symptoms of infection, may have adaptive value if sickness interferes with the expression of T-mediated behaviors important for male reproductive success. We conduct a classic hormone replacement experiment to examine if T suppresses sickness behavior in a seasonally-breeding songbird, Gambel's white-crowned sparrow (Zonotrichia leucophrys gambelii). Triggered experimentally by bacterial lipopolysaccharide (LPS), sickness behavior includes decreased activity, anorexia, and weight loss. Gonadectomized (GDX) males that were treated with silastic implants filled with T exhibited suppression of behavioral and physiological responses to LPS compared to GDX and sham-GDX controls given empty implants. Sickness responses of control groups were statistically indistinguishable. T-implanted birds had significantly higher plasma T than control groups and levels were within the range associated with aggressive interactions during male-to-male contests. These findings imply that suppression of sickness behavior could occur when T is elevated to socially-modulated levels. Alternatively, it is possible that this suppressive effect is mediated through a stress-induced mechanism, as corticosterone levels were elevated in T-implanted subjects compared to controls. We propose that males wounded and infected during contests may gain a brief selective advantage by suppressing sickness responses that would otherwise impair competitive performance. The cost of immunosuppression would be manifested in males through an increased susceptibility to disease, which is presumably offset by capitalizing upon limited reproductive opportunities.