Preferential induction of apoptotic cell death in melanoma cells as compared with normal keratinocytes using a non-thermal plasma torch

Selective induction of apoptosis in melanoma cells is optimal for therapeutic development. To achieve this goal, a non-thermal helium plasma torch was modified for use on cultured cells in a temperature-controlled environment. Melanoma cells were targeted with this torch (1) in parallel cultures with keratinocytes, (2) in co-culture with keratinocytes and (3) in a soft agar matrix. Melanoma cells displayed high sensitivity to reactive oxygen species generated by the torch and showed a 6-fold increase in cell death compared with keratinocytes. The extent of cell death was compared between melanoma cells and normal human keratinocytes in both short-term (5 min) co-culture experiments and longer assessments of apoptotic cell death (18–24 h). Following a 10 sec plasma exposure there was a 4.9-fold increase in the cell death of melanoma vs. keratinocytes as measured after 24 h at the target site of the plasma beam. When the treatment time was increased to 30 sec, a 98% cell death was reported for melanoma cells, which was 6-fold greater than the extent of cell death in keratinocytes. Our observations further indicate that this preferential cell death is largely due to apoptosis.. In addition, we report that this non-thermal plasma torch kills melanoma cells growing in soft agar, suggesting that the plasma torch is capable of inducing melanoma cell death in 3D settings. We demonstrate that the presence of gap junctions may increase the area of cell death, likely due to the “bystander effect” of passing apoptotic signals between cells. Our findings provide a basis for further development of this non-invasive plasma torch as a potential treatment for melanoma.     

Electron microscopic localization of nerve growth factor receptor (p75)-immunoreactivity in pars caudalis / medullary dorsal horn of the cat

Previous studies have demonstrated the presence of nerve growth factor receptor [NGFr(p75)]-immunoreactivity (IR) in the spinal trigeminal nucleus of both 8–10 week-old kittens and mature cats. Most of the NGFr(p75)-IR is lost following retrogasserian rhizotomy, indicating that the majority of the NGFr(p75)-IR within the spinal trigeminal nucleus is of trigeminal primary afferent origin. Here, we examined the ultrastructural localization of NGFr(p75)-IR within lamina II outer of pars caudalis/medullary dorsal horn in the mature cat. Lamina II outer represents a location where dense NGFr(p75)-IR is seen with the light microscope. The NGFr(p75)-IR identified with the electron microscope was located within small thinly myelinated and unmyelinated axons and within axon terminals. The terminals with NGFr(p75)-IR typically formed asymmetric synaptic specializations onto dendritic profiles and at times were postsynaptic to other axon terminals at symmetric synaptic specializations. The terminals with NGFr(p75)-IR were either simple (associated with a single profile) or more complex, such as those that typically formed the central element in synaptic glomeruli. The NGFr(p75)-IR in terminals was especially prominent on microtubules and the plasmalemma and these findings are consistent with proposed roles for NGFr(p75) in axoplasmic/neuronal transport and as a membrane protein, respectively. The profiles with NGFr(p75)-IR seen with the electron microscope indicate a primary afferent origin and show some similarities when compared to other markers of primary afferent fibers such as calcitonin gene-related peptide. In addition, a possible role for NGFr(p75) in the transmission of nociceptive stimuli is also discussed.     

Building Academic Geriatric Nursing Capacity: results after the first 10 years and implications for the future

In 2000, the John A. Hartford Foundation launched a multi-million dollar investment in Building Academic Geriatric Nursing Capacity (BAGNC) at the American Academy of Nursing (AAN). After a decade of focused support to increase scholarship, research, leadership, and institutional collaboration, is there evidence this program is successful in achieving its goals? Equally important, as the need for quality geriatric nursing care increases with the expanding aging population and associated complex health conditions, how does the experience and outcomes of this program inform nursing’s future? To address both questions, the authors first provide an overview of geriatric nursing prior to and up to the time the BAGNC program began, then review results of an external evaluation of the BAGNC program, and finally propose goals and strategies for the next 20 years of academic geriatric nursing.     

Reading and interpreting economic evaluations in rheumatoid arthritis: an assessment of selected instruments for critical appraisal

OBJECTIVE: To describe and compare the relative attributes (reliability, ease of use, applicability, and relevance) of different assessment tools for economic analyses as they pertain to rheumatoid arthritis (RA) literature. METHODS: An expert panel, comprising rheumatology researchers and clinicians, operationalized 2 economic appraisal instruments and applied them to 11 articles used for analysis. Each expert reviewed 3 articles, with each article independently reviewed by a pair of experts. A summary score for each article per appraisal instrument was calculated by dividing the number of items that received a "positive" response by the total number of items in the appraisal instrument. RESULTS: Scores for each article were similar across reviewers and appraisal instruments. CONCLUSION: There is a need for a more comprehensive approach for evaluating this rapidly growing body of economic literature that is not only valid and reliable, but also easy to apply and understand. Although consistency between reviewers was good on both guidelines, inter-guideline discrepancies were noted and reviewers reported some difficulty in using the operationalized format.     

Hippocampal BDNF mediates the efficacy of exercise on synaptic plasticity and cognition

We found that a short exercise period enhanced cognitive function on the Morris water maze (MWM), such that exercised animals were significantly better than sedentary controls at learning and recalling the location of the platform. The finding that exercise increased brain-derived neurotrophic factor (BDNF), a molecule important for synaptic plasticity and learning and memory, impelled us to examine whether a BDNF-mediated mechanism subserves the capacity of exercise to improve hippocampal-dependent learning. A specific immunoadhesin chimera (TrkB-IgG), that mimics the BDNF receptor, TrkB, to selectively bind BDNF molecules, was used to block BDNF in the hippocampus during a 1-week voluntary exercise period. After this, a 2-trial-per-day MWM was performed for 5 consecutive days, succeeded by a probe trial 2 days later. By inhibiting BDNF action we blocked the benefit of exercise on cognitive function, such that the learning and recall abilities of exercising animals receiving the BDNF blocker were reduced to sedentary control levels. Inhibiting BDNF action also blocked the effect of exercise on downstream systems regulated by BDNF and important for synaptic plasticity, cAMP response-element-binding protein (CREB) and synapsin I. Specific to exercise, we found an association between CREB and BDNF expression and cognitive function, such that animals who were the fastest learners and had the best recall showed the highest expression of BDNF and associated CREB mRNA levels. These findings suggest a functional role for CREB under the control of BDNF in mediating the exercise-induced enhancement in learning and memory. Our results indicate that synapsin I might also contribute to this BDNF-mediated mechanism.     

Familial aggregation of energy intake in children

BACKGROUND: Uncompensated overnutrition promotes obesity, but the controls of children's eating behavior are poorly understood. Insights may be achieved by testing whether the eating patterns of children are associated with demographic variables or whether they aggregate among family members. OBJECTIVE: We tested whether children's total energy intake and macronutrient intake and their ability to compensate for earlier energy intake were associated with sociodemographic variables and anthropometric indexes. We also tested whether these behavioral traits aggregate among siblings. DESIGN: Thirty-two sibling pairs aged 3-7 y consumed a multi-item lunch preceded by a low-energy (12.55 kJ) or high-energy (627.60 kJ) preload drink. Mixed-models regression tested the associations between children's energy intake, demographic variables, and anthropometric measures. An intraclass correlation coefficient quantified the family correlation of the measures of children's eating. RESULTS: Children consumed significantly more total energy after consuming the low-energy preload ( +/- SD: 2237.39 +/- 1176.45 kJ) than after consuming the high-energy preload (1601.18 +/- 930.65 kJ). Compensation ability was unrelated to the children's age, sex, or ethnicity. Total energy and macronutrient intake, but not compensation propensity, were associated among siblings. CONCLUSIONS: The familial association of total energy and macronutrient intakes, independent of anthropometric measures, suggests genetic or home environmental influences specific to these behaviors. Short-term energy compensation, although very accurate within this sample, showed no significant familial correlation.     

Identifying consumer-provider benefits in evaluations of consumer-delivered services

Consumer-delivered services are different in many ways from traditional mental health services and require unique approaches to how they are studied. This includes attending to benefits to both consumer-providers as well as to program participants. A qualitative study was conducted to systematically examine consumer-provider benefits. A thematic analysis of interviews with 14 peer providers from Friends Connections, a peer-support program for persons with recurring mental health and substance use disorders, was conducted. Responses indicate that peer providers benefit from their roles as helpers, a finding consistent with the helper-therapy principle. Implications for research and policy are discussed.     

Depletion of Deoxyribonucleotide Pools Is an Endogenous Source of DNA Damage in Cells Undergoing Oncogene-Induced Senescence

In normal human cells, oncogene-induced senescence (OIS) depends on induction of DNA damage response. Oxidative stress and hyperreplication of genomic DNA have been proposed as major causes of DNA damage in OIS cells. Here, we report that down-regulation of deoxyribonucleoside pools is another endogenous source of DNA damage in normal human fibroblasts (NHFs) undergoing HRAS^G12V-induced senescence. NHF-HRAS^G12V cells underexpressed thymidylate synthase (TS) and ribonucleotide reductase (RR), two enzymes required for the entire de novo deoxyribonucleotide biosynthesis, and possessed low dNTP levels. Chromatin at the promoters of the genes encoding TS and RR was enriched with retinoblastoma tumor suppressor protein and histone H3 tri-methylated at lysine 9. Importantly, ectopic coexpression of TS and RR or addition of deoxyribonucleosides substantially suppressed DNA damage, senescence-associated phenotypes, and proliferation arrest in two types of NHF-expressing HRAS^G12V. Reciprocally, short hairpin RNA-mediated suppression of TS and RR caused DNA damage and senescence in NHFs, although less efficiently than HRAS^G12V. However, overexpression of TS and RR in quiescent NHFs did not overcome proliferation arrest, suggesting that unlike quiescence, OIS requires depletion of dNTP pools and activated DNA replication. Our data identify a previously unknown role of deoxyribonucleotides in regulation of OIS.Oncogene-induced senescence (OIS) represents an important fail-safe mechanism that suppresses proliferation of premalignant cells.^1–3 Compelling evidence suggests that the response to DNA damage is one of the intrinsic processes required for the induction of OIS.^4–7 It was shown that aberrant activation of HRAS in human fibroblasts induces hyperreplication of genomic DNA, which leads to alterations in progression of DNA replication fork, generation of single- and double-strand DNA breaks (SSBs and DSBs, respectively), and activation of DNA damage response (DDR).⁶ SSBs induce DDR by engaging serine/threonine-protein kinase ATR (ataxia telangiectasia and Rad3-related protein) that transmits signaling to checkpoint kinase 1 (CHK1).⁸ CHK1 phosphorylates CDC25 protein, one of the key regulators of cell cycle progression, and targets it for degradation.⁸ DSBs initiate DDR that depends on another serine/threonine protein kinase, ataxia telangiectasia mutated (ATM).⁹ Activation of ATM results in phosphorylation of several targets, including the histone H2A variant H2AX,¹⁰ p53 tumor suppressor,^11,12 and CHK2 kinase.¹³ Both ATR and ATM signaling pathways are activated in normal human fibroblasts (NHFs) undergoing HRAS^G12V-induced senescence,^4–7 whereas ATM and CHK2 are required for this senescence because their individual short hairpin RNA (shRNA)-mediated inhibition enabled NHFs to overcome proliferation arrest and other senescence-associated phenotypes.^6,7At the same time, studies conducted in yeasts and mammalian cells report that stalling of DNA replication fork and activation of ATR/CHK1 and ATM/CHK2 pathways can be induced by pharmacologic depletion of all or selected nucleotide pools.^14,15 In the present study, we investigated endogenous processes that caused DNA damage in human fibroblasts undergoing OIS and demonstrated that DNA damage at least partially originates from underexpression of key enzymes involved in de novo deoxyribonucleoside biosynthesis and subsequent depletion of endogenous dNTP pools. We propose that nucleotide deficiency caused by aberrant expression of activated HRAS contributes to OIS.