183 resultados para Neuronal Death


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Voltage-gated sodium channels (VGSC) have been linked to inherited forms of epilepsy. The expression and biophysical properties of VGSC in the hippocampal neuronal culture model have not been clarified. In order to evaluate mechanisms of epileptogenesis that are related to VGSC, we examined the expression and function of VGSC in the hippocampal neuronal culture model in vitro and spontaneously epileptic rats (SER) in vivo. Our data showed that the peak amplitude of transient, rapidly–inactivating Na+ current (INa,T) in model neurons was significantly increased compared with control neurons, and the activation curve was shifted to the negative potentials in model neurons in whole cell recording by patch–clamp. In addition, channel activity of persistent, non-inactivating Na+ current (INa,P) was obviously increased in the hippocampal neuronal culture model as judged by single–channel patch–clamp recording. Furthermore, VGSC subtypes NaV1.1, NaV1.2 and NaV1.3 were up-regulated at the protein expression level in model neurons and SER as assessed by Western blotting. Four subtypes of VGSC proteins in SER were clearly present throughout the hippocampus, including CA1, CA3 and dentate gyrus regions, and neurons expressing VGSC immunoreactivity were also detected in hippocampal neuronal culture model by immunofluorescence. These findings suggested that the up-regulation of voltage-gated sodium channels subtypes in neurons coincided with an increased sodium current in the hippocampal neuronal culture model, providing a possible explanation for the observed seizure discharge and enhanced excitability in epilepsy.

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Objectives: (1) To determine informal caregivers perceptions about place of care and place of death; and (2) to identify variables associated with a home death among terminally ill individuals who received in-home support services in a publicly funded home care system. Participants and design: A total of 216 informal caregivers participated in a bereavement interview. Data collection included care recipient and informal caregiver characteristics, the use of and satisfaction with community services, and preferences about place of death. Results: Most caregivers reported that they and the care recipient had a preferred place of death (77 and 68%, respectively) with over 63% reporting home as the preferred place of death. Caregivers had a greater preference for an institutional death (14%) than care recipients (4.7%). While 30% of care recipients did not die in their preferred location, most caregivers (92%) felt, in retrospect, that where the care recipient died was the appropriate place of death. Most caregivers reported being satisfied with the care that was provided. The odds of dying at home were greater when the care recipient stated a preference for place of death (OR: 2.92; 95% CI: 1.25, 6.85), and the family physician made home visits during the care recipients last month of life (Univariate odds ratios (OR): 4.42; 95% CI: 1.46, 13.36). Discussion: The ethic of self-control and choice for the care recipient must be balanced with consideration for the well being of the informal caregiver and responsiveness of the community service system. © 2005 Edward Arnold (Publishers) Ltd.

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Objectives: To determine the factors associated with a home death among older adults who received palliative care nursing home services in the home. Methods: The participants in this retrospective cohort study were 151 family caregivers of patients who had died approximately 9 months prior to the study telephone interview. The interview focused on the last year of life and covered two main areas, patient characteristics and informal caregiver characteristics. Results: Odds ratios [OR] and 95% confidence intervals [95% CI] were used to determine which of the 15 potential informal caregiver and seven patient predictor variables were associated with dying at home. Multivariate analysis revealed that the odds of dying at home were greater when the patient lived with a caregiver [OR = 7.85; 95% CI = (2.35, 26.27)], the patient stated a preference to die at home [OR= 6.51; 95% CI = (2.66,15.95)], and the family physician made home visits [OR = 4.79; 95% CI = (1.97,11.64)]. However the odds were lower for patients who had caregivers with fair to poor health status [OR = 0.22; 95% CI = (0.07, 0.65)] and for patients who used hospital palliative care beds [OR = 0.31; 95% CI = (0.12, 0.80)]. Discussion: The findings suggest that individuals who indicated a preference to die at home and resided with a healthy informal caregiver had better odds of dying at home. Home visits by a family physician were also associated with dying at home.

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Context: Shared care models integrating family physician services with interdisciplinary palliative care specialist teams are critical to improve access to quality palliative home care and address multiple domains of end-of-life issues and needs. Objectives: To examine the impact of a shared care pilot program on the primary outcomes of symptom severity and emotional distress (patient and family separately) over time and, secondarily, the concordance between patient preferences and place of death. Methods: An inception cohort of patients (n = 95) with advanced, progressive disease, expected to die within six months, were recruited from three rural family physician group practices (21 physicians) and followed prospectively until death or pilot end. Serial measurement of symptoms, emotional distress (patient and family), and preferences for place of death was performed, with analysis of changes in distress outcomes assessed using t-tests and general linear models. Results: Symptoms trended toward improvement, with a significant reduction in anxiety from baseline to 14 days noted. Symptom and emotional distress were maintained below high severity (7-10), and a high rate of home death compared with population norms was observed. Conclusion: Future controlled studies are needed to examine outcomes for shared care models with comparison groups. Shared care models build on family physician capacity and as such are promising in the development of palliative home care programs to improve access to quality palliative home care and foster health system integration. © 2011 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.

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Objective: The purpose of this study was to describe the value of a formal room blessing ritual held within a long-term care facility, from the perspectives of staff, residents, and family members. Method: A qualitative research study involving interviews with staff, residents, and family members was conducted to examine the perceived value of a room blessing ritual. Results: Twenty-four room blessing attendees participated in the study (nine staff, eight residents, and seven family members). Attendees felt that the room blessing provided an opportunity to formally acknowledge the death of the resident and their grief; the majority felt that this was a positive experience and that it provided an element of closure. Staff members and residents expressed their appreciation for the opportunity to connect with family members of the deceased to express their condolences during the ritual. Participants also identified the inclusivity of the ritual (i.e., an open invitation to all staff, residents, and family members) as a positive aspect that served as a reminder that others shared in their grief. Staff members felt that blessing the room for the new resident was an important component of the ritual, helping to bridge the gap between mourning and welcoming a new person. Staff, residents, and family members felt that the room blessing positively reflected the mission and values of the facility. The most highly valued aspect of the ritual for all attendees was the sharing of stories about the deceased to celebrate that person's life. Significance of results: Long-term care facilities need to recognize that formal supports to manage the bereavement needs of staff and residents, such as a room blessing ritual, should be incorporated into their model for managing end-of-life care, given the relationship between the emotional health of staff and the quality of care provided for residents. © 2012 Cambridge University Press.

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Patients' desire for hastened death within the context of advanced disease and palliative care is a controversial topic, frequently discussed in the international literature. Much of the discussion has focused on opinion and debate about ethical matters related to hastened death. Not many research studies seem to have specifically targeted why palliative care patients may desire hastened death, and few have focused on clinical guidelines for responding to such requests.

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Background: In recent years, much progress has been made in the treatment of multiple myeloma. However, a major limitation of existing chemotherapeutic drugs is the eventual emergence of resistance; hence, the development of novel agents with new mechanisms of action is pertinent. Here, we describe the activity and mechanism of action of pyrrolo-1,5-benzoxazepine-15 (PBOX-15), a novel microtubule-targeting agent, in multiple myeloma cells.

Methods: The anti-myeloma activity of PBOX-15 was assessed using NCI-H929, KMS11, RPMI8226, and U266 cell lines, and primary myeloma cells. Cell cycle distribution, apoptosis, cytochrome c release, and mitochondrial inner membrane depolarisation were analysed by flow cytometry; gene expression analysis was carried out using TaqMan Low Density Arrays; and expression of caspase-8 and Bcl-2 family of proteins was assessed by western blot analysis.

Results: Pyrrolo-1,5-benzoxazepine-15 induced apoptosis in ex vivo myeloma cells and in myeloma cell lines. Death receptor genes were upregulated in both NCI-H929 and U266 cell lines, which displayed the highest and lowest apoptotic responses, respectively, following treatment with PBOX-15. The largest increase was detected for the death receptor 5 (DR5) gene, and cotreatment of both cell lines with tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), the DR5 ligand, potentiated the apoptotic response. In NCI-H929 cells, PBOX-15-induced apoptosis was shown to be caspase-8 dependent, with independent activation of extrinsic and intrinsic apoptotic pathways. A caspase-8-dependent decrease in expression of Bim(EL) preceded downregulation of other Bcl-2 proteins (Bid, Bcl-2, Mcl-1) in PBOX-15-treated NCI-H929 cells.

Conclusion: PBOX-15 induces apoptosis and potentiates TRAIL-induced cell death in multiple myeloma cells. Thus, PBOX-15 represents a promising agent, with a distinct mechanism of action, for the treatment of this malignancy. British Journal of Cancer (2011) 104, 281-289. doi: 10.1038/sj.bjc.6606035 www.bjcancer.com Published online 21 December 2010 (C) 2011 Cancer Research UK

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Programmed cell death (PCD) is executed by proteases, which cleave diverse proteins thus modulating their biochemical and cellular functions. Proteases of the caspase family and hundreds of caspase substrates constitute a major part of the PCD degradome in animals(1,2). Plants lack close homologues of caspases, but instead possess an ancestral family of cysteine proteases, metacaspases(3,4). Although metacaspases are essential for PCD(5-7), their natural substrates remain unknown(4,8). Here we show that metacaspase mcII-Pa cleaves a phylogenetically conserved protein, TSN (Tudor staphylococcal nuclease), during both developmental and stress-induced PCD. TSN knockdown leads to activation of ectopic cell death during reproduction, impairing plant fertility. Surprisingly, human TSN (also known as p100 or SND1), a multifunctional regulator of gene expression(9-15), is cleaved by caspase-3 during apoptosis. This cleavage impairs the ability of TSN to activate mRNA splicing, inhibits its ribonuclease activity and is important for the execution of apoptosis. Our results establish TSN as the first biological substrate of metacaspase and demonstrate that despite the divergence of plants and animals from a common ancestor about one billion years ago and their use of distinct PCD pathways, both have retained a common mechanism to compromise cell viability through the cleavage of the same substrate, TSN.

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Plant embryogenesis is intimately associated with programmed cell death. The mechanisms of initiation and control of programmed cell death during plant embryo development are not known. Proteolytic activity associated with caspase-like proteins is paramount for control of programmed cell death in animals and yeasts. Caspase family of proteases has unique strong preference for cleavage of the target proteins next to asparagine residue. In this work, we have used synthetic peptide substrates containing caspase recognition sites and corresponding specific inhibitors to analyse the role of caspase-like activity in the regulation of programmed cell death during plant embryogenesis. We demonstrate that VEIDase is a principal caspase-like activity implicated in plant embryogenesis. This activity increases at the early stages of embryo development that coincide with massive cell death during shape remodeling. The VEIDase activity exhibits high sensitivity to pH, ionic strength and Zn2+ concentration. Altogether, biochemical assays show that VEIDase plant caspase-like activity resembles that of both mammalian caspase-6 and yeast metacaspase, YCA1. In vivo, VEIDase activity is localised specifically in the embryonic cells during both the commitment and in the beginning of the execution phase of programmed cell death. Inhibition of VEIDase prevents normal embryo development via blocking the embryo-suspensor differentiation. Our data indicate that the VEIDase activity is an integral part in the control of plant developmental cell death programme, and that this activity is essential for the embryo pattern formation.

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Cell and tissue patterning in plant embryo development is well documented. Moreover, it has recently been shown that successful embryogenesis is reliant on programmed cell death (PCD). The cytoskeleton governs cell morphogenesis. However, surprisingly little is known about the role of the cytoskeleton in plant embryogenesis and associated PCD. We have used the gymnosperm, Picea abies , somatic embryogenesis model system to address this question. Formation of the apical-basal embryonic pattern in P. abies proceeds through the establishment of three major cell types: the meristematic cells of the embryonal mass on one pole and the terminally differentiated suspensor cells on the other, separated by the embryonal tube cells. The organisation of microtubules and F-actin changes successively from the embryonal mass towards the distal end of the embryo suspensor. The microtubule arrays appear normal in the embryonal mass cells, but the microtubule network is partially disorganised in the embryonal tube cells and the microtubules disrupted in the suspensor cells. In the same embryos, the microtubule-associated protein, MAP-65, is bound only to organised microtubules. In contrast, in a developmentally arrested cell line, which is incapable of normal embryonic pattern formation, MAP-65 does not bind the cortical microtubules and we suggest that this is a criterion for proembryogenic masses (PEMs) to passage into early embryogeny. In embryos, the organisation of F-actin gradually changes from a fine network in the embryonal mass cells to thick cables in the suspensor cells in which the microtubule network is completely degraded. F-actin de-polymerisation drugs abolish normal embryonic pattern formation and associated PCD in the suspensor, strongly suggesting that the actin network is vital in this PCD pathway.

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ABSTRACT (250 words)
BACKGROUND: The mechanism underlying respiratory virus-induced cough hypersensitivity is unknown. Up-regulation of airway neuronal receptors responsible for sensing physical and chemical stimuli is one possibility and the transient receptor potential (TRP) channel family are potential candidates. We have used an in vitro model of sensory neurones and human rhinovirus (HRV-16) to study the effect of virus infection on TRP expression.
METHODS: IMR32 neuroblastoma cells were differentiated in culture to express three TRP channels, TRPV1, TRPA1 and TRPM8. Flow cytometry and qRT-PCR were used to measure TRP channel protein and mRNA levels following inoculation with live virus, inactivated virus, virus- induced soluble factors or pelleted virus particles. Multiplex bioassay was used to determine nerve growth factor (NGF), interleukin (IL)-1ß, IL-6 and IL-8 levels in response to infection.
RESULTS: Early up-regulation of TRPA1 and TRPV1 expression occurred 2 to4 hours post infection. This was independent of replicating virus as virus induced soluble factors alone were sufficient to increase channel expression 50 and 15 fold, respectively. NGF, IL-6 and IL-8 levels, increased in infected cell supernatants, represent possible candidates. In contrast, TRPM8 expression was maximal at 48 hours (9.6 fold) and required virus replication rather than soluble factors
CONCLUSIONS We show for the first time that rhinovirus can infect neuronal cells. Furthermore, infection causes up-regulation of TRP channels by channel specific mechanisms. Increase in TRPA1 and TRPV1 levels can be mediated by soluble factors induced by infection whereas TRPM8 requires replicating virus. TRP channels may be novel therapeutic targets for controlling virus-induced cough.

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Malone, C. A. T., Bonanno, A., Gouder, T., Stoddart, S. K. F., and Trump, D.