Light microscopic immunocytochemical identification of leucine enkephalin

Leucine-enkephalin is a potent and naturally-occurring opioid peptide which serves to inhibit other neurotransmitters involved with pain perception, thereby reducing its emotional and physical impact. Nevertheless, there is little data in the literature concerning leucine-enkephalin-immunoreactivity (Leu-enk-ir) in the human claustrum. The objectives of this study were to confirm the existence of leucine-enkephalin immunoreactive neurons and fibers in the human claustrum. Light microscopy was used to describe their morphology and distribution. Samples of claustrum were obtained from the brains of two females (39 and 48 years of age) and two males (27 and 42 years of age). The brains did not show any overt signs of pathology or trauma. Immunoreactivity to Leuenk was assessed via the Avidin-Biotin Complex Method. Light-microscopic analysis confirmed the presence of Leu-enk-ir neurons and fibres in all areas of the human claustrum. The cell bodies varied in shape and size, and were divided into three groups: small, medium and large. The density of immunostaining varied both within and between the cell types, with some neurons, staining more darkly or lightly than others. The large and medium sized cells most likely correspond to claustrocortical projection neurons while the small-sized cells appear to be inhibitory interneurons. It is our hope that these results will be contributed to a better understanding the functions of claustrum, in both health and disease, given its relationship with the development of autism, schizophrenia, Alzheimer disease, Parkinson disease and Huntington disease

Subdivisions of the Auditory Midbrain (N. Mesencephalicus Lateralis, pars dorsalis) in Zebra Finches Using Calcium-Binding Protein Immunocytochemistry

The midbrain nucleus mesencephalicus lateralis pars dorsalis (MLd) is thought to be the avian homologue of the central nucleus of the mammalian inferior colliculus. As such, it is a major relay in the ascending auditory pathway of all birds and in songbirds mediates the auditory feedback necessary for the learning and maintenance of song. To clarify the organization of MLd, we applied three calcium binding protein antibodies to tissue sections from the brains of adult male and female zebra finches. The staining patterns resulting from the application of parvalbumin, calbindin and calretinin antibodies differed from each other and in different parts of the nucleus. Parvalbumin-like immunoreactivity was distributed throughout the whole nucleus, as defined by the totality of the terminations of brainstem auditory afferents; in other words parvalbumin-like immunoreactivity defines the boundaries of MLd. Staining patterns of parvalbumin, calbindin and calretinin defined two regions of MLd: inner (MLd.I) and outer (MLd.O). MLd.O largely surrounds MLd.I and is distinct from the surrounding intercollicular nucleus. Unlike the case in some non-songbirds, however, the two MLd regions do not correspond to the terminal zones of the projections of the brainstem auditory nuclei angularis and laminaris, which have been found to overlap substantially throughout the nucleus in zebra finches

Learning to walk the community of practice tightrope

Background: The Community of Practice Research was established as a new local health district service initiative. The community comprises novice and experienced multidisciplinary health researchers. Aims: This paper reflects our experience of being Community of Practice Research members and aims to explore the practice development principles aligned to the purpose, progress and outcomes of this community. Conclusions: The journey is compared to walking a tightrope from the beginning to the end. Success in moving forward is attributed to positive leadership and group dynamics enabling a supportive environment. This environment allowed for different types of learning: new research skills and new understandings about oneself. Competing demands such as fluctuating membership and leadership, and the selection of a large initial project were identified as barriers to the Community of Practice Research. Implications for practice: - As well as contributing to communities\u27 shared goals members should identify and make explicit their own learning goals to themselves, the community and their managers - Community of practice meetings should include regular facilitated reflection about the learning that is occurring, the challenges and assumptions being made by the group, and the way forward - A community of practice uses social processes to aid learning and collaboration across disciplines and organisations and therefore has potential to promote local culture chang

CT angiographic study of the role of both willis circle and vertebral arteries during selective cerebral perfusion - a study in 105 patients

Unilateral selective cerebral perfusion (SCP) is a method for cerebral protection in aortic arch surgery. However, variations of the circle of Willis (CoW) could vitiate its protective effect. The aim of our present work was to prospectively analyze variations of CoW and vertebral arteries using CT angiography. From January, 2008 to July, 2008, a total of 105 consecutive patients underwent CT-angiography of the CoW in the Division of Radiology, St. Ekaterina University Hospital of Sofia. There were at least six CoW configurations that could lead to significant hypo perfusion during unilateral SCP: i) type IA - hypoplasia or absence of left posterior communicating artery (PComA) (in 41.9% of the patients); ii) type IB - hypoplasia or absence of anterior communicating artery (AComA) (in 1.9%); iii) type IIA - hypoplasia or absence of both left PComA and AComA (in 6.67%); iv) type IIB - hypoplasia or absence of left P1 or right vertebral artery (VA) (in 6.67%); v) type III - hypoplasia or absence of right A1 (in 8.57%), and vi) type IV - hypoplasia or absence of both right A1 and right VA or both right A1 and left PComA (in 0.95%). All these types were present in a 66.67% of all the examined patients. Our present study showed that CoW variations are presented in significant number of patients. These results support the need of extensive preoperative examination and meticulous intraoperative monitoring of cerebral perfusion during unilateral SCP.Scripta Scientifica Medica 2012; 44(2): 73-77

Re-conceptualising culture in Virtual Learning Environments: from an 'essentialist' to a 'negotiated' perspective

The notion of 'culture' as an essential attribute of individuals and groups, owed to national or ethnic background, is critiqued in this article as unhelpful to the project of understanding how diverse participants in virtual learning environments (VLEs) individually and jointly construct a culture of interaction. An alternative conceptualisation of culture in VLEs is proposed, which views online discussion as just one of the sites in which the culture of a VLE is negotiated. Other sites are to be found in institutional practices of teaching and learning at a distance, and in the wider cultural narratives of the Internet. Examples from two online masters courses in online and distance education are used to contextualise this concept of culture, exploring the differences in patterns of participation that are produced by contrasting institutional cultures, even though such participation is explicitly valorised as the means and the subject of the learning that goes on in both these courses. Some implications for the understanding and management of student diversity in these environments are considered, in particular the need for emerging cultural narratives around VLEs to reflect all aspects of student engagement in distance education, not just those which relate to online interaction