The structural and functional integrity of peripheral nerves depends on the glial-derived signal desert hedgehog

We show that desert hedgehog ( dhh), a signaling molecule expressed by Schwann cells, is essential for the structural and functional integrity of the peripheral nerve. Dhh-null nerves display multiple abnormalities that affect myelinating and nonmyelinating Schwann cells, axons, and vasculature and immune cells. Myelinated fibers of these mice have a significantly increased ( more than two times) number of Schmidt-Lanterman incisures ( SLIs), and connexin 29, a molecular component of SLIs, is strongly upregulated. Crossing dhh-null mice with myelin basic protein ( MBP)-deficient shiverer mice, which also have increased SLI numbers, results in further increased SLIs, suggesting that Dhh and MBP control SLIs by different mechanisms. Unmyelinated fibers are also affected, containing many fewer axons per Schwann cell in transverse profiles, whereas the total number of unmyelinated axons is reduced by approximately one-third. In dhh-null mice, the blood-nerve barrier is permeable and neutrophils and macrophage numbers are elevated, even in uninjured nerves. Dhh-null nerves also lack the largest-diameter myelinated fibers, have elevated numbers of degenerating myelinated axons, and contain regenerating fibers. Transected dhh nerves degenerate faster than wild-type controls. This demonstrates that a single identified glial signal, Dhh, plays a critical role in controlling the integrity of peripheral nervous tissue, in line with its critical role in nerve sheath development ( Parmantier et al., 1999). The complexity of the defects raises a number of important questions about the Dhh-dependent cell-cell signaling network in peripheral nerves

Regulation of Liver Tyrosine Aminotransferase by Endogenous Factors in the Mouse

The levels of mouse liver tyrosine aminotransferase (TAT) are shown to increase rapidly and transiently during and after various challenges (e.g., exposure to cold or shaking) to the homeostatic machinery of the fasted mouse. The increase of TAT is dependent on gene activity. Recent feeding and adrenalectomy are shown to inhibit the induction of TAT during the challenge of cold

Detection of elliptical shapes via cross-entropy clustering

The problem of finding elliptical shapes in an image will be considered. We discuss the solution which uses cross-entropy clustering. The proposed method allows the search for ellipses with predefined sizes and position in the space. Moreover, it works well for search of ellipsoids in higher dimensions

c-Jun reprograms Schwann cells of injured nerves to generate a repair cell essential for regeneration.

The radical response of peripheral nerves to injury (Wallerian degeneration) is the cornerstone of nerve repair. We show that activation of the transcription factor c-Jun in Schwann cells is a global regulator of Wallerian degeneration. c-Jun governs major aspects of the injury response, determines the expression of trophic factors, adhesion molecules, the formation of regeneration tracks and myelin clearance and controls the distinctive regenerative potential of peripheral nerves. A key function of c-Jun is the activation of a repair program in Schwann cells and the creation of a cell specialized to support regeneration. We show that absence of c-Jun results in the formation of a dysfunctional repair cell, striking failure of functional recovery, and neuronal death. We conclude that a single glial transcription factor is essential for restoration of damaged nerves, acting to control the transdifferentiation of myelin and Remak Schwann cells to dedicated repair cells in damaged tissue

‘They’re more like ordinary stroppy British women’: Attitudes and expectations of maternity care professionals to UK-born ethnic minority women

Objective To explore the attitudes and expectations of maternity care professionals to UK-born ethnic minority mothers. Methods Qualitative in-depth interviews with 30 professionals from eight NHS maternity units in England that provide services for large proportions of women of black Caribbean, black African, Indian, Pakistani and Irish descent. Results All the professionals reported providing care to both UK-born and migrant mothers from ethnic minorities. Most of them felt that they could differentiate between UK-born and migrant mothers based mainly on language fluency and accent. ‘Westernized dress’ and ‘freedom’ were also cited as indicators. Overall, professionals found it easier to provide services to UK-born mothers and felt that their needs were more like those of white English mothers than those of migrant mothers. UK-born mothers were generally thought to be assertive and expressive, and in control of care-related decision-making whereas some South Asian Muslim women were thought to be constrained by family influences. Preconceived ideas about ethnic minority mothers' tolerance of pain in labour, use of pharmacological pain relief measures and mode of delivery were recurring themes. Women's education and social class were felt to be major influences on the uptake of maternity care, regardless of ethnicity. Conclusions Professionals appeared to equate the needs of UK-born ethnic minority women with those of white English women. Overall, this has positive implications for care provision. Despite this, specific behavioural expectations and unconscious stereotypical views were evident and have the potential to affect clinical practice

Gender violence in schools: taking the ‘girls-as-victims’ discourse forward

This paper draws attention to the gendered nature of violence in schools. Recent recognition that schools can be violent places has tended to ignore the fact that many such acts originate in unequal and antagonistic gender relations, which are tolerated and ‘normalised’ by everyday school structures and processes. After examining some key concepts and definitions, we provide a brief overview of the scope and various manifestations of gender violence in schools, noting that most research to date has focused on girls as victims of gender violence within a heterosexual context and ignores other forms such as homophobic and girl violence. We then move on to look at a few interventions designed to address gender violence in schools in the developing world and end by highlighting the need for more research and improved understanding of the problem and how it can be addressed

Guidelines for the verification and validation of expert system software and conventional software: Validation scenarios. Volume 6

This report is the sixth volume in a series of reports describing the results of the Expert System Verification and Validation (V&V) project which is jointly funded by the US Nuclear Regulatory Commission and the Electric Power Research Institute. The ultimate objective is the formulation of guidelines for the V&V of expert systems for use in nuclear power applications. This activity was concerned with the development of a methodology for selecting validation scenarios and subsequently applying it to two expert systems used for nuclear utility applications. Validation scenarios were defined and classified into five categories: PLANT, TEST, BASICS, CODE, and LICENSING. A sixth type, REGRESSION, is a composite of the others and refers to the practice of using trusted scenarios to ensure that modifications to software did not change unmodified functions. Rationale was developed for preferring scenarios selected from the categories in the order listed and for determining under what conditions to select scenarios from other types. A procedure incorporating all of the recommendations was developed as a generalized method for generating validation scenarios. The procedure was subsequently applied to two expert systems used in the nuclear industry and was found to be effective, given that an experienced nuclear engineer made the final scenario selections. A method for generating scenarios directly from the knowledge base component was suggested