Genetics of cell-type-specific post-transcriptional gene regulation during human neurogenesis

The function of some genetic variants associated with brain-relevant traits has been explained through colocalization with expression quantitative trait loci (eQTL) conducted in bulk post-mortem adult brain tissue. However, many brain-trait associated loci have unknown cellular or molecular function. These genetic variants may exert context-specific function on different molecular phenotypes including post-transcriptional changes. Here, we identified genetic regulation of RNA-editing and alternative polyadenylation (APA), within a cell-type-specific population of human neural progenitors and neurons. More RNA-editing and isoforms utilizing longer polyadenylation sequences were observed in neurons, likely due to higher expression of genes encoding the proteins mediating these post-transcriptional events. We also detected hundreds of cell-type-specific editing quantitative trait loci (edQTLs) and alternative polyadenylation QTLs (apaQTLs). We found colocalizations of a neuron edQTL in CCDC88A with educational attainment and a progenitor apaQTL in EP300 with schizophrenia, suggesting genetically mediated post-transcriptional regulation during brain development lead to differences in brain function.

Differential effects of ozone on airway and tissue mechanics in obese mice

Obesity is an important risk factor for asthma. We recently reported increased ozone (O(3))-induced hyperresponsiveness to methacholine in obese mice (Shore SA, Rivera-Sanchez YM, Schwartzman IN, and Johnston RA. J Appl Physiol 95: 938-945, 2003). The purpose of this study was to determine whether this increased hyperresponsiveness is the result of changes in the airways, the lung tissue, or both. To that end, we examined the effect of O(3) (2 parts/million for 3 h) on methacholine-induced changes in lung mechanics with the use of a forced oscillation technique in wild-type C57BL/6J mice and mice obese because of a genetic deficiency in leptin (ob/ob mice). In ob/ob mice, O(3) increased baseline values for all parameters measured in the study: airway resistance (Raw), lung tissue resistance (Rtis), lung tissue damping (G) and elastance (H), and lung hysteresivity (eta). In contrast, no effect of O(3) on baseline mechanics was observed in wild-type mice. O(3) exposure significantly increased Raw, Rtis, lung resistance (Rl), G, H, and eta responses to methacholine in both groups of mice. For G, Rtis, and Rl there was a significant effect of obesity on the response to O(3). Our results demonstrate that both airways and lung tissue contribute to the hyperresponsiveness that occurs after O(3) exposure in wild-type mice. Our results also demonstrate that changes in the lung tissue rather than the airways account for the amplification of O(3)-induced hyperresponsiveness observed in obese mice.

Emulsified anterior chamber silicone oil and glaucoma

PURPOSE

This retrospective study was undertaken to assess the occurrence of postoperative anterior chamber emulsified silicone oil after intravitreal instillation and to examine the relation between such emulsification and new postoperative glaucoma.

METHODS

Forty-eight consecutive eyes received intravitreal silicone oil, were followed for at least 1 year, and were evaluated postoperatively by gonioscopy on at least one occasion. Eight eyes received 1000 cs oil, and 40 eyes received 5000 cs oil from which low molecular weight contaminants were removed. All aphakic and pseudophakic eyes received an inferior iridectomy. Oil was removed in 19% of eyes during follow-up.

RESULTS

Fifty-six percent of eyes manifested anterior chamber emulsified oil postoperatively. The oil was typically identified only on gonioscopy. This complication developed in 50% of eyes receiving 1000 cs oil and 58% of eyes receiving highly homogeneous 5000 cs oil. Of the 48 eyes, new postoperative glaucoma best explained by interval angle oil emulsification developed in 5 (10%).

CONCLUSION

Anterior chamber oil emulsification occurred frequently, despite inferior peripheral iridectomy in aphakic or pseudophakic eyes and the use of highly purified, higher viscosity oil in 83% of eyes. In this series, new glaucoma in the setting of angle oil emulsification only developed in 10% of eyes. The glaucoma was managed medically in four of five patients.

Pigmentary changes in acquired retinoschisis

We reviewed retrospectively the records of patients referred for retinal examination and found 375 eyes (233 patients) with acquired retinoschisis. Of the 375 eyes, 85 had outer layer retinal breaks, 27 had retinal detachments, and 29 had pigmentary lines. Twenty-five of the 29 pigmentary lines (86.2%) demarcated either retinal detachment or outer retinal layer breaks.

Management of rhegmatogenous retinal detachment with macula detached. Steroids, choroidal detachment, and acuity

One hundred thirty-four consecutive eyes with rhegmatogenous retinal detachment involving the macula were evaluated with reference to the effectiveness of systemic steroids in preventing choroidal detachment after scleral buckling surgery and in facilitating both anatomic and functional success. The occurrence of postoperative choroidal detachment was inversely related to the routine intravenous administration of steroids under antibiotic coverage beginning in the recovery room (P = 0.014). Eyes so treated were free of both clinically significant infection and extrusion. The infrequent but worrisome complication of angle closure sufficient to require choroidal tap did not occur among treated eyes. Routine steroid use may have been associated with increased preservation of acuity at the level of 20/200 or better (P = 0.043).