AC/PC Intraocular Lens Exchange with Penetrating Keratoplasty in Pseudophakic Bullous Keratopathy

Background

Evaluation of penetrating keratoplasty in cases of pseudophakic bullous keratopathy with AC/PC IOL exchange.

Methods

This retrospective study included 120 cases of pseudophakic bullous keratopathy managed over 9 years at three tertiary care eye centres followed up for 4 years. Cases were taken up for penetrating keratoplasty along within adjuvant procedures like IOL explantation and Secondary Posterior Chamber IOL implantation over the frill of posterior capsule.

Results

Lens exchange with Penetrating Keratoplasty (PK) was done in 93 and PK without lens exchange in 27 cases. 25% required systemic steroids for 2-3 weeks. Re-grafting was performed in 5% and 85% attained moderate visual acuity.

Conclusion

Intra ocular lens exchange and Posterior chamber IOL are suitable for penetrating keratoplasty in terms of optical clarity, graft survival and visual outcome.Key Words: PBK, IOL exchange (AC/PC)     

Mediastinal tuberculous lymphadenitis: CT manifestations

An analysis was done of computed tomographic (CT) scans of 23 Korean patients who had presented with a mediastinal or hilar mass on plain chest radiographs and had subsequently been found to have tuberculous lymphadenitis. Most patients were young adults. Findings of pulmonary tuberculosis were seen on plain radiographs in 14 patients. On CT, findings were of an overwhelming preponderance of involvement of the right paratracheal and tracheobronchial nodes. After injection of contrast medium, nodes larger than 2 cm in diameter invariably showed central areas of relative low density and peripheral rim enhancement. Enhanced walls were usually irregular in thickness. Some smaller nodes did not show low-density areas, but instead showed varying degrees of homogeneous enhancement. Although metastatic nodes can be of low density, experience in this study suggests that mediastinal lymphadenopathy in a young adult with the CT findings described above is characteristic enough to support a diagnosis of tuberculosis.     

A novel gene, AF1q, fused to MLL in t(1;11) (q21;q23), is specifically expressed in leukemic and immature hematopoietic cells

Translocations involving chromosomal band 11q23 are associated with leukemias. These translocations fuse the MLL, a gene with sequence homology to the Drosophila trithorax, to genes from a number of other chromosomal loci. We have characterized two t(1;11)(q21;q23) translocations that fuse the MLL gene to a novel gene, AF1q on chromosomal band 1q21, in two infants with acute myelomonocytic leukemia (AMMOL). In one of these patients, der(11) represents an inframe fusion of the N-terminal portion of MLL gene to the complete AF1q open reading frame, whereas der(1) does not give rise to an open reading frame. This observation suggests that the N-terminal portion of MLL gene is critical for leukemogenesis in translocations involving band 11q23. The predicted wild-type AF-1q product is a 9-kD protein with no similarity to any other protein in the data banks. The AF1q mRNA is highly expressed in the thymus but not in peripheral lymphoid tissues. In contrast to its restricted distribution in normal hematopoietic tissue, AF1q was expressed in all leukemic cell lines tested.     

The Adaptive Nature of Eye Movements in Linguistic Tasks: How Payoff and Architecture Shape Speed‐Accuracy Trade‐Offs

We explore the idea that eye‐movement strategies in reading are precisely adapted to the joint constraints of task structure, task payoff, and processing architecture. We present a model of saccadic control that separates a parametric control policy space from a parametric machine architecture, the latter based on a small set of assumptions derived from research on eye movements in reading (Engbert, Nuthmann, Richter, & Kliegl, 2005; Reichle, Warren, & McConnell, 2009). The eye‐control model is embedded in a decision architecture (a machine and policy space) that is capable of performing a simple linguistic task integrating information across saccades. Model predictions are derived by jointly optimizing the control of eye movements and task decisions under payoffs that quantitatively express different desired speed‐accuracy trade‐offs. The model yields distinct eye‐movement predictions for the same task under different payoffs, including single‐fixation durations, frequency effects, accuracy effects, and list position effects, and their modulation by task payoff. The predictions are compared to—and found to accord with—eye‐movement data obtained from human participants performing the same task under the same payoffs, but they are found not to accord as well when the assumptions concerning payoff optimization and processing architecture are varied. These results extend work on rational analysis of oculomotor control and adaptation of reading strategy (Bicknell & Levy, 2010b ; McConkie, Rayner, & Wilson, 1973; Norris, 2009; Wotschack, 2009) by providing evidence for adaptation at low levels of saccadic control that is shaped by quantitatively varying task demands and the dynamics of processing architecture.