The coordinate frame of pop-out learning

Saccades are ubiquitous in natural vision. One way to generate a coherent representation of a scene across saccades is to produce an extra-retinal coordinate frame (such as a head-based representation). We investigate this issue by behavioral means: Participants learned to detect a 3D-pop-out target in a fixed position. Next, target was relocated in one coordinate frame while maintaining it fixed in the others. Performance was severely affected only when the change in target position occurred in a retinotopic coordinate frame. This further suggests that perceptual learning occurs in retinotopic regions having receptive fields restricted within a hemifield.     

Bariatric Surgery-Associated Myelopathy

Bariatric surgery is gaining acceptance as an efficient treatment modality for adults and adolescents with morbid obesity. The early postbariatric period has the potential to induce an immunomodulatory imbalance due to the development or worsening of nutritional deficiencies, changes in hormonal balance (specifically after sleeve gastrectomy), and a shift in the proinflammatory cytokine profile along with a major change in the gut microbiome and permeability. These changes may induce encephalomyelitic T cell activity, change neural barrier permeability, and induce gut dysbioisis, favoring a proinflammatory metabolic profile. Such changes, in genetically prone individuals or those with additional risk factors, may lead to the development of myelopathy, particularly MS.Key MessagePostbariatric myelopathy is rare but should be considered in bariatric patients with relevant complaints in the postoperative period.     

An extension of the Minute Virus of Mice tissue tropism

Well-defined tissue tropism makes Autonomous Parvoviruses a valuable model for studies of virus-cell interactions and gene therapy research. We developed a new Minute Virus of Mice variant, different from the known prototype (MVMp) and immunosuppressive (MVMi) strains. The new virus variant, designated F1, was isolated from the culture of semi-permissive Fisher Rat Fibroblasts, F111, infected with MVMp. The F1 genome carried point mutations in regions known to determine the mutually restricted host ranges of MVMp and MVMi. In F111 cells, F1 cytotoxicity, gene expression and multiplication were significantly higher compared to MVMp. Conversely the wild-type virus propagated in MVMp-permissive cells more efficiently than the F1. Reversion of the F1-specific mutations to wild-type MVMp sequence, following reverse-passaging of the mutant virus in MVMp-permissive cells, confirmed a specific adaptation of the F1 virus to F111 cells. Considerable divergence in tissue specificities between the wild-type and mutant viruses was demonstrated in vivo.     

Mechanisms of T regulatory cell function

Regulatory T cells (Treg) play a pivotal role in tolerance to self-antigens and tissue grafts, and suppression of autoimmune reactions. These cells modulate the intensity and quality of immune reactions through attenuation of the cytolytic activities of reactive immune cells. Treg cells operate primarily at the site of inflammation where they modulate the immune reaction through three major mechanisms: a) direct killing of cytotoxic cells through cell-to-cell contact, b) inhibition of cytokine production by cytotoxic cells, in particular interleukin-2, c) direct secretion of immunomodulatory cytokines, in particular TGF-beta and interleukin-10. In addition to differential contributions of these mechanisms under variable inflammatory conditions, mechanistic complexity and diversity evolves from the diverse tasks performed by various Treg cell subsets in different stages of the immune reaction. Here we attempt to integrate the current experimental evidence to delineate the major suppressive pathways of Treg cells.     

Post-transplant diabetes mellitus in lung transplant recipients: incidence and risk factors

Objective: Post-transplant diabetes mellitus (PTDM) is a common and potentially serious complication after solid organ transplantation. There are only a few data, however, about the incidence of DM in patients undergoing lung transplantation. Patients and methods: The medical records of 119 consecutive patients who underwent lung transplantation from 1998 to September 2004 were reviewed. Patients were divided in three groups according to their diabetes status, including pre-transplant DM, the PTDM group and those without DM. Patient records and all laboratory data were reviewed and the clinical course of diabetes was monitored. All recipients were treated with tacrolimus based regimen. Results: Mean follow-up for all patients was 25 ± 10. Twenty-three patients had DM in the pre-lung transplantation (LTX) DM group. PTDM developed in 34 of the remaining 96 patients (35.4%) with an incidence of 20%, 23% after 6 months and 12 months post-transplant. No significant difference was noted between 12 and 24 months post-LTX. The patients who developed DM were older (57 ± 15 vs 53 ± 13 years, p = 0.009), had increased BMI (26 ± 5 vs 24 ± 4, p = 0.0001), shorter time from diagnosis to LTX (21 ± 13 vs 28 ± 18 months, p = 0.007) more cytomegalovirus infection and more acute rejection and hyperglycemia in the first month after LTX. Four patients died in the PTDM group compared to nine patients in the no-DM group (12% vs 14%; p = 0.72). Conclusions: Post-transplant diabetes is a common complication in lung transplant patients receiving tacrolimus-based immunosuppression. The risk for developing PTDM is greatest among older recipients, those obese, and among recipients with more rejections episodes.     

DEATH OF A SPOUSE: ILLUSORY BASIC ASSUMPTIONS AND CONTINUATION OF BONDS

Recently psychologists have questioned the traditional model of grief, arguing that the continuation of bonds with the deceased spouse is generally adaptive. Continuing bonds can be seen as attempts to cope with the loss of a spouse but also with the shattering of the normal illusory basic assumptions about the self,the world, and the future. At this time, however, scholarship has provided few concepts to understand how continuing bonds and illusions express adaptive or maladaptive forms of grief. Therefore, the purpose of this article is to identify, in the context of the illusory basic assumptions, the circumstances by which the bond with the deceased is adaptive or maladaptive. So Epstein (1980) distinguished between higher order postulates and lower order postulates. Higher order postulates are an abstract form of schemas, or generalized theories about the self, the world, and the future, that are resistant to changes. On the other hand, lower order postulates are a concrete form of schemas normally flexible and responsive to the changes in the reality of the new situation. On the basis of this distinction, the author argues that higher order bonds or symbolic bonds are adaptive, whereas lower order bonds or concrete bonds are maladaptive.