Disruption of neurofascin localization reveals early changes preceding demyelination and remyelination in multiple sclerosis.

Saltatory conduction in the nervous system is enabled through the intimate association between the leading edge of the myelin sheath and the axonal membrane to demarcate the node of Ranvier. The 186 kDa neuron specific isoform of the adhesion molecule neurofascin (Nfasc186) is required for the clustering of voltage gated Na+ channels at the node, whilst the 155 kDa glial specific isoform (Nfasc155) is required for the assembly of correct paranodal junctions. In order to understand the relationship between these vital structures and how they are affected in multiple sclerosis we have examined the expression of Nfasc155 and Nfasc186 in areas of inflammation, demyelination and remyelination from post-mortem brains. Fourteen cases of neuropathologically confirmed multiple sclerosis (8 female and 6 male; post-mortem delay 7-24 h; age 37-77 years; and disease duration 15-40 years), comprising 20 tissue blocks with 32 demyelinating or remyelinating lesions, were used in this study. A significant early alteration in Nfasc155+ paranodal structures occurs within and adjacent to actively demyelinating white matter lesions that are associated with damaged axons. Shaker-type Kv1.2 channels, normally located distally to the paranode, overlapped with the disrupted Nfasc155+ structures. In the absence of Nfasc155, Kv1.2 channels abutted normally clustered Nfasc186+ nodes, indicating that complete disruption of the paranodal structure and movement of Kv1.2 channels precede alterations at the node itself. Within areas of partial remyelination, a number of atypical triple-Nfasc155+ structures were noted that may represent transient oligodendrocyte-axonal contacts during the process of myelin repair or aberrant interactions. Within shadow plaques discretely clustered Na+v, Nfasc186+ and Nfasc155+ domains indicated the restoration of normal nodal architecture. The alterations in oligodendrocyte Nfasc155 expression that accompany inflammation and demyelination suggest an ongoing disruption to the axonal-oligodendrocyte complex within newly forming as well as established lesions in multiple sclerosis, resulting in destruction of the Nfasc186+/Na+v nodal complex vital to successful fast neurotransmission in the CNS.

A clinical teaching guide for psychiatric mental health nursing: a qualitative outcome analysis project.

Limited curriculum enhancement resources are available to psychiatric nurse educators. This article provides a clinical teaching guide for novice instructors teaching an introductory psychiatric nursing course. The investigation is grounded in a constructivist theoretical framework and extends a previous case study project that explored how students learn during a mental health practicum (Melrose 1998, Melrose & Shapiro 1999). The guide was tested and modified by applying a qualitative outcome analysis methodology. Insight into interpreting student behaviour and providing appropriate and stage-specific teaching tools is revealed. Theoretical components, assessment questions for teachers, student behavioural signs and teaching strategies are identified and discussed to describe significant features in creating personally meaningful learning experiences.

Students' perceptions of their psychiatric mental health clinical nursing experience: a personal construct theory exploration.

Personal construct theory and repertory grid technique provides a suitable framework for exploring Registered Nursing students' perceptions of their psychiatric practicum. This descriptive research was designed to understand students' own ways of constructing knowledge during their mental health clinical experience. A constructivist conceptual perspective and George Kelly's personal construct psychology were the theoretical bases of the research. A qualitative case study methodology allowed creation of and reflection on personal construct changes as provided in participants' review of repertory grid ideas about psychiatric nursing. The participants were six Canadian second-year nursing students in a Baccalaureate programme that integrated psychiatric and medical surgical nursing curricula. The following three overarching themes were identified and are used to explain and describe significant features of the psychiatric clinical experience: 1) students' anxiety related more to feeling unable to help than to interactions with mentally ill patients; 2) students' feelings of a lack of inclusion in staff nurse groups; 3) student emphasis on the importance of nonevaluated student-instructor discussion time.

Immunohistochemical studies of amyloid P component and fibronectin in erythropoietic protoporphyria.

Immunofluorescence staining of exposed skin from patients with erythropoietic protoporphyria (EPP) with antibodies to serum amyloid P component (SAP) and to fibronectin produced striking fluorescence of abnormal vascular structures in the upper dermis. An appearance of linear fluorescence along the dermo-epidermal junction with anti-SAP was the result of confluent staining of papillary oxytalan fibres. Amyloid P component (AP) was localized in ultrastructural immunoperoxidase studies to the peripheral (abluminal) regions of thickened dermal vessel walls, the site of maximum concentration of an amorphous matrix containing microfibrillar structures; antibodies to SAP did not bind to leaflets of the reduplicated vascular basal lamina. The characteristic thickening and reduplication of blood vessel walls seen with the electron microscope in EPP therefore involves increased local deposition of both AP and fibronectin.

Immunohistochemical studies of amyloid P component distribution in normal human skin.

The distribution of amyloid P component (AP) in normal human skin was investigated by a light and electron microscopic immunoperoxidase technique, using antibodies to serum amyloid P component (SAP). AP, or an immunologically cross-reactive protein, was found to be specifically localized to the microfibrils of papillary oxytalan fibers and to the peripheral microfibrillar mantle surrounding the elastin core of mature elastic fibers in the reticular dermis; collagen fibers were not stained with anti-SAP. AP was not detected in the dermal-epidermal basement membrane or in the basement membranes surrounding dermal papillary blood vessels and eccrine structures. These findings, which establish the detailed distribution of normal tissue AP in the skin, provide a basis for further studies of the function and behavior of this protein in health and disease.