A Matter of Substance, April 2012

A publication of the IDPH Division of Behavioral Health to find out what's happening with Substance Abuse Prevention and Treatment.

A Matter of Substance, May 2012

A publication of the IDPH Division of Behavioral Health to find out what's happening with Substance Abuse Prevention and Treatment.

A Matter of Substance, October 2012

A publication of the IDPH Division of Behavioral Health to find out what's happening with Substance Abuse Prevention and Treatment.

A Matter of Substance, June 2012

A publication of the IDPH Division of Behavioral Health to find out what's happening with Substance Abuse Prevention and Treatment.

A Matter of Substance, August 2012

A publication of the IDPH Division of Behavioral Health to find out what's happening with Substance Abuse Prevention and Treatment.

A Matter of Substance, September 2012

A publication of the IDPH Division of Behavioral Health to find out what's happening with Substance Abuse Prevention and Treatment.

Fas (CD95/APO-1) limits the expansion of T lymphocytes in an environment of limited T-cell antigen receptor/MHC contacts.

Fas-deficient mice (Fas(lpr/lpr)) and humans have profoundly dysregulated T lymphocyte homeostasis, which manifests as an accumulation of CD4(+) and CD8(+) T cells as well as an unusual population of CD4(-)CD8(-)TCRαβ(+) T cells. To date, no unifying model has explained both the increased T-cell numbers and the origin of the CD4(-)CD8(-)TCRαβ(+) T cells. As Fas(lpr/lpr) mice raised in a germ-free environment still manifest lymphadenopathy, we considered that this process is primarily driven by recurrent low-avidity TCR signaling in response to self-peptide/MHC as occurs during homeostatic proliferation. In these studies, we developed two independent systems to decrease the number of self-peptide/MHC contacts. First, expression of MHC class I was reduced in OT-I TCR transgenic mice. Although OT-I Fas(lpr/lpr) mice did not develop lymphadenopathy characteristic of Fas(lpr/lpr) mice, in the absence of MHC class I, OT-I Fas(lpr/lpr) T cells accumulated as both CD8(+) and CD4(-)CD8(-) T cells. In the second system, re-expression of β(2)m limited to thymic cortical epithelial cells of Fas(lpr/lpr) β(2)m-deficient mice yielded a model in which polyclonal CD8(+) thymocytes entered a peripheral environment devoid of MHC class I. These mice accumulated significantly greater numbers of CD4(-)CD8(-)TCRαβ(+) T cells than conventional Fas(lpr/lpr) mice. Thus, Fas shapes the peripheral T-cell repertoire by regulating the survival of a subset of T cells proliferating in response to limited self-peptide/MHC contacts.

Improved segmentation of deep brain grey matter structures using magnetization transfer (MT) parameter maps.

Basal ganglia and brain stem nuclei are involved in the pathophysiology of various neurological and neuropsychiatric disorders. Currently available structural T1-weighted (T1w) magnetic resonance images do not provide sufficient contrast for reliable automated segmentation of various subcortical grey matter structures. We use a novel, semi-quantitative magnetization transfer (MT) imaging protocol that overcomes limitations in T1w images, which are mainly due to their sensitivity to the high iron content in subcortical grey matter. We demonstrate improved automated segmentation of putamen, pallidum, pulvinar and substantia nigra using MT images. A comparison with segmentation of high-quality T1w images was performed in 49 healthy subjects. Our results show that MT maps are highly suitable for automated segmentation, and so for multi-subject morphometric studies with a focus on subcortical structures.

A Matter of Substance, November 2012

A publication of the IDPH Division of Behavioral Health to find out what's happening with Substance Abuse Prevention and Treatment.

A Matter of Substance, December 2012

A publication of the IDPH Division of Behavioral Health to find out what's happening with Substance Abuse Prevention and Treatment.