Ciliary neurotrophic factor enhances neuronal survival in embryonic rat hippocampal cultures

First described as a survival factor for chick ciliary ganglion neurons, ciliary neurotrophic factor (CNTF) has recently been shown to promote survival of chick embryo motor neurons. We now report neurotrophic effects of CNTF toward three populations of rat hippocampal neurons, the first demonstration of effects of CNTF upon rodent CNS neurons in culture. CNTF elicited an increase in the neurofilament content of hippocampal cultures prepared from embryonic day 18 (E18) rat brain. This was accompanied by increases of 2-, 28-, and 3-fold in the number of GABAergic, cholinergic, and calbindin-immunopositive cells, respectively. CNTF totally prevented the 67% loss of GABAergic neurons that occurred in control cultures over 8 d. CNTF also increased high-affinity GABA uptake and glutamic acid decarboxylase activity. Effects of CNTF were in all cases dose dependent, with maximal stimulation at approximately 100 pg/ml. When addition was delayed for 3 d, CNTF failed to elicit increases either in the number of cholinergic neurons or in GABA uptake

Expression of ciliary neurotrophic factor and the neurotrophins - Nerve and growth factor, brain-derived neurotrophic factor and neurotrophin 3 - in cultured rat hippocampal astrocytes

Cultured astrocytes are known to possess a range of neurotrophic activities in culture. In order to examine which factors may be responsible for these activities, we have examined the expression of the genes for four known neurotrophic factors - ciliary neurotrophic factor (CNTF), nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin 3 (NT3) - in purified astrocyte cultures derived from neonatal rat hippocampus. Hippocampal astrocytes were found to expresssd mRNA for three neurotrophic factors - CNTF, NGF and NT3 - at significantly higher levels than other cultured cell types or cell lines examined. BDNF messenger RNA (mRNA), however, was undetectable in these astrocytes. The levels of CNTF, NGF and NT3 mRNA in astrocytes were largely unaffected by their degree of confluency, while serum removal caused only a transient decrease in mRNA levels, which returned to basal levels within 48 h. Astrocyte-derived CNTF was found to comigrate with recombinant rat CNTF at 23 kD on a Western blot. Immunocytochemical analysis revealed strong CNTF immunoreactivity in the cytoplasm of astrocytes, weak staining in the nucleus, but no CNTF at the cell surface. NGF and NT3 were undetectable immunocytochemically. CNTF-like activity, as assessed by bioassay on ciliary ganglion neurons, was found in the extract of cultured astrocytes but not in conditioned medium, whereas astrocyte-conditioned medium supported survival of dorsal root ganglion neurons but not ciliary or nodose ganglion neurons. This conditioned medium activity was neutralized with antibodies to NGF. Astrocyte extract also supported survival of dorsal root ganglion and nodose ganglion neurons, but these activities were not blocked by anti-NGF. Part, but not all, of the activity in astrocyte extracts which sustained nodose ganglion neurons could be attributed to CNTF

Incidence, mechanisms, and characteristics of injuries in pole dancers: A prospective cohort study

Objective: Pole dancing is a challenging physical activity. Prospective injury studies in pole dancing are lacking. The aim of this study was to describe the incidence, mechanisms, and characteristics of injuries in pole dancers. Methods: A total of 66 pole dancers from 41 studios across Australia were prospectively followed over 12 months. An intake questionnaire was administered including items on pole dancers\u27 demographics and training characteristics. Exposure was assessed using a daily online training diary. Self-reported injury data were collected via an incident report form and subsequently coded using the Orchard Sports Injury Classification System. Injuries occurring during pole-specific and pole-related activities were included in the analyses. Results: The sample included 63 females and 3 males, mean age 32.3 ± 8.9 years and mean pole training experience 3.5 ± 2.8 years. 25 of 66 participants completed the full study. The 1-year incidence of all new injuries was 8.95 / 1,000 exposure hours (95 % CI 6.94 - 10.96), 7.65 / 1,000 hrs (95 % CI 5.79 - 9.51) for pole-specific injuries and 1.29 / 1,000 hrs (95 % CI 0.53 - 2.06) for pole-related injuries. A total of 103 injuries occurred, 62.1 % of which were sudden onset and 37.9 % gradual onset. Mechanism of onset included 54.4 % acute and 45.6 % repetitive in nature. Shoulder (20.4 %) and thigh (11.7 %, majority ham¬string) were the most reported anatomic injury sites. Non-contact mechanisms accounted for the majority of injuries (57.3 %). The most reported primary contributor to injury onset at the shoulder were manoeuvres characterised by loaded internal humeral rotation (33.3 %), and at the hamstring were manoeuvres and postures involving front splits (100.0 %). Conclusion: The findings indicate that pole dancers are at high risk for injuries. Future research is needed to understand the biomechani¬cal demand of manoeuvres and training characteristics of pole dancing (e.g., workload and recovery) to guide the development of preventative interventions, particularly targeted toward the shoulder and hamstring

The neurotrophin family of NGF-related neurotrophic factors

The recent molecular cloning of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) has established the existence of an NGF-related family of neurotrophic factors - the neurotrophins. Purification and recombinant production of BDNF and NT-3 has allowed the initiation or extension of in vitro studies of the neuronal specificity of each of these factors. We have found that NT-3, like NGF and BDNF, promotes survival and neurite outgrowth from certain populations of sensory neurons. There appear to be both distinct and overlapping specificities of the 3 neurotrophins towards peripheral neurons sympathetic neurons and subpopulations of neural crest and neural placode-derived sensory neurons. Using cultures of central nervous system neurons, we have recently established that BDNF: (i) promotes the survival and phenotypic differentiation of rat septal cholinergic neurons, a property consistent with the discovery of high levels of BDNF mRNA expression within the hippocampus; (ii) promotes the survival of rat nigral dopaminergic neurons and furthermore protects these neurons from two dopaminergic neurotoxins, 6-hydroxydopamine (6-OHDA) and MPTP. Thus the neurotrophic effects of these factors towards peripheral neurons and neuronal populations known to degenerate in two of the major human neurodegenerative diseases - Alzheimer's and Parkinson's disease - provokes the question of whether neurotrophic factors may have therapeutic potential in halting the progression and ameliorating the symptoms of devastating neurological disorders of the CNS or PNS, or improving regeneration of neurons of CNS or PNS after traumatic injury

Resource Advantage Theory and Fair Trade Social Enterprises

This paper will investigate the competitive position of both fair trade (FT) social enterprises Divine Chocolate Ltd (Divine) and Cafédirect in their respective UK markets, namely chocolate confectionery and hot beverages. Using Eisenhardt’s (1989, 1991, and 2007) approach to building theory from multiple case studies, this four-year PhD study aims to identify the resources that enable FT social enterprises to compete. This research draws on recent developments in competition theory such as resource advantage theory (R-A theory), termed a general theory of competition. The paper will critically analyse if the social and ethical elements of these firm’s product offerings really constitute meaningful differentiators (i.e. comparative advantage) as required by R-A theory (Hunt and Morgan 1995, Hunt 2001). Hunt and Derozier (2004) argue that R-A theory can ground theories of business and marketing strategy and therefore identifying the competitive resources of FT social enterprises will have important strategic implications. The research findings show that both Divine and Cafédirect have established a mainstream competitive position in specific product segments and distribution channels. Thus illustrating intra-industry demand to be heterogeneous. In addition, both companies have been a catalyst for change by influencing the strategies and policies of both branded manufactures and retailers such as Cooperative Food (CF). The key theoretical contribution validates ‘social resources’ and its three inter-related components: ethical and social commitments, connections with partners and consistency of behaviour as a resource to extend R-A theory. These ‘social resources’ in combination with both relational resources and threshold capabilities (e.g. product quality) result in a competitive position for both case organisations. The ethical and social commitments of ‘social resources’ also appears to provide an example of an ethical underpinning to Relationship Marketing. The identification of ‘social resources’ has important wider implications for both other social enterprises and those companies who are aiming to achieve a competitive position based on social commitments