Pituitary fossa: chemical shift effect in MR imaging

The effect of chemical shift on magnetic resonance (MR) imaging of the pituitary fossa was studied. Healthy volunteers underwent conventional MR imaging of the pituitary fossa and then imaging with the frequency-encoding gradient reversed or with the phase- and frequency-encoding gradients interchanged. Comparison of the image pairs in each subject showed that the thin, black stripe evident at the water-fat interface within the pituitary fossa was altered when the gradients were changed. Therefore, the low-intensity signal within the pituitary fossa is a chemical shift misregistration effect.     

Growth factor pre-treatment differentially regulates phosphoinositide turnover downstream of lysophospholipid receptor and metabotropic glutamate receptors in cultured rat cerebrocortical astrocytes

Reactive gliosis is an aspect of neural plasticity and growth factor (GF) stimulation of astrocytes in vitro is widely regarded as a model system to study astrocyte plasticity. Astrocytes express receptors for several ligands including lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P), agonists for the G-protein-coupled lysophospholipid receptors (lpRs). Activation of lpRs by LPA or S1P leads to multiple pharmacological effects including the influx of calcium, phosphoinositide (PI) hydrolysis, phosphorylation of extracellular receptor regulated kinase (ERK), release of arachidonic acid, and induces mitogenesis. Treatment of astrocytes in vitro with a growth factor cocktail (containing epidermal growth factor [EGF], basic fibroblast growth factor [bFGF] and insulin) led to a marked attenuation of lpR-induced PI hydrolysis. In contrast, under identical conditions, GF treatment led to marked potentiation of PI hydrolysis downstream of activation of another abundantly expressed G-protein coupled receptor, mGluR5. Quantitative gene expression analysis of GF-treated or control astrocytes by TaqMan RT-PCR indicated that GF treatment did not change gene expression of lpa1 and s1p1, but increased gene expression of s1p5 which is expressed at very low levels in basal conditions. These results suggest that GF differentially affected PLC activation downstream of mGluR5 versus lpR activation and that the changes in mRNA levels of lpRs do not account for marked attenuation of agonist-induced phosphoinositide turnover.     

The meaning of work after acquired brain injury.

PURPOSE: Research in the field of brain injury rehabilitation has tended to regard return to work as a measure of outcome. Researchers have not paid particular attention to the experiences of people living with a brain injury. The aim of the phenomenological study reported here was to identify and describe what characterizes the meaning of work to those with acquired brain injury. METHODS: Ten participants of working age were interviewed about the meaning of work 1-5 years after being inflicted with a brain injury. Data were analyzed and interpreted using the Empirical Phenomenological Psychological method. RESULTS: The findings revealed a meaning structure consisting of four main characteristics. Work was no longer experienced as the primary event in life and the social dimension had become more important. The perceived competence and work identity were threatened after the injury. A common theme across all interviews was the struggle to return to a state of normality, and working was considered to be evidence of success. CONCLUSION: The findings described the altered meaning of work 1-5 years after brain injury. This knowledge should lead to an increased understanding among occupational therapists engaged in work rehabilitation after brain injury and can serve as a basis for individualized intervention strategies.     

Anulus fibrosus in bulging intervertebral disks

In this investigation the association of radial tears of the anulus fibrosus and bulging of the intervertebral disk was studied. An index of disk bulging was measured in sagittal anatomic sections in 149 lumbar disks from 31 cadavers. The indexes of disk bulging were correlated with stages of disk development and the presence of an annular tear. The largest disk-bulging indexes were always associated with radial tears of the anulus. Eighty-four percent of the disks with radial tears had disk-bulging indexes greater than 2.5 mm. Most normal adult disks had an index of less than 2.5 mm. The results challenge the concept that the anulus fibrosus is intact in bulging disks, although ruptured in herniated disks.