bluuebunny/crossref_metadata_2025 huggingface dataset:
SITUAÇÕES DE MORTE E MORRER E AS PSICOPATOLOGIAS ENVOLVIDAS EM CRIANÇAS E ADOLESCENTES REFUGIADOS – UMA REVISÃO SISTEMÁTICA COM METANÁLISE
Authors: Dias Joselito Batista , Rolim Neto Modesto Leite
Published: April 2018

Introdução: São muito raros os estudos sobre os transtornos mentais envolvidos em situações de morte e morrer, principalmente quando se considera as psicopatologias em crianças e adolescentes refugiados. A consequência é a pequena disponibilidade de dados e ausência de um perfil epidemiológico real, dificultando a adequação das políticas de saúde e a avaliação da efetividade dessas ações junto os sujeitos expostos a  situação de refúgio. Método: Revisão sistemática com metanálise seguindo o protocolo PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analyse), de 2015 a 2018, através das bases de dados: LILACS – Latin American and Caribbean Health Sciences Literature, SciELO – Scientific Eletronic Library OnLine e BVS - Virtual Health Library. A análise envolveu as seguintes palavras-chave: “modelos de atenção primária e secundária em saúde mental”, “criança”, “adolescentes”, “políticas e serviços em saúde mental” e “refugiados” através do operador booleano # and. A literatura cinzenta (literatura não controlada por editores científicos ou comerciais), também foi utilizada através da busca manual (handsearching). Resultados: Uma análise conjunta das estratégias pontuadas nos artigos analisados mostra um Odds Ratio combinado de 1,291 IC [1,054 – 1,582] o que demonstra a falta de efetividade do uso das estratégias na elaboração de aparatos institucionais no campo de saúde mental em situações de morte e morrer em crianças e adolescentes refugiados. O valor de “p” da distribuição qui-quadrado resultou em 0,9753 o que  rejeita a hipótese de associação entre a presença de estratégias em saúde mental e cuidados paliativos em situações de refúgio. Conclusão: Uma análise combinada de todas as estratégias pontuadas nos estudos analisados demonstra a falta de efetividade da utilização das estratégias na elaboração de aparatos institucionais no campo de saúde mental e processos de morte e morrer. Alguns desafios, porém, permanecem no âmbito do refúgio, tais como fomento da rede de assistência, domínio e ampliação dos recursos diagnósticos e terapêuticos, estímulo à reinserção social, abordagem conjunta da condição clínica, mental e socioeconômica, capacitação dos profissionais de saúde e intervenções em observância à autonomia e às individualidades do sujeito em situações limítrofes naquilo que circunda os indicadores de estresse envolvidos na morte e o morrer.
Are there rings around Pluto?‎
Authors: Rawal J.J , Nikouravan Bijan
Published: April 2018

Considering effects of tidal plus centrifugal stress acting on icy-rocks and the tensile strength thereof, icy-rocks being in the density range (1–2.4) g cm-3 which had come into existence as collisional ejecta (debris) in the vicinity of Pluto at the time when Pluto-Charon system came into being as a result of a giant impact of a Kuiper Belt Object on the primordial Pluto, it is shown, here, that these rocks going around Pluto in its vicinity are under slow disruption generating a stable ring structure consisting of icy-rocks of diameters in the range (20–90) km, together with fine dust and particles disrupted off the rocks, and spread all over the regions in their respective Roche Zones, various Roche radii being in ~1/2 three-body mean motion resonance. Calculations of gravitational spheres of influence of Pluto which turns out to be 4.2 x 106 km for prograde orbits and 8.5 x 106 km for retrograde orbits together with the existence of Kuiper Belt in the vicinity of Pluto assure that there may exist a few rocks (satellites)/dust rings/sheets so far undiscovered moving in prograde orbits around the planet and few others which are distant ones and move around Pluto in the region between 4.2x106 km and 8.5x106 km in retrograde orbits.
Halaman Sampul
Authors: Sampul Halaman
Published: April 2018

Cover, Dewan Redaksi. Daftar Isi
A Tactical Periodization Approach for Rugby Union
Authors: Tee Jason C. , Ashford Michael , Piggott David
Published: April 2018

THE CONCEPT OF TACTICAL PERIODIZATION HAS BEEN POPULARIZED BY A NUMBER OF SUCCESSFUL, HIGH-PROFILE SOCCER COACHES. MORE RECENTLY, REPORTS HAVE INDICATED THAT TACTICAL PERIODIZATION APPROACHES ARE BEING USED WITHIN ELITE RUGBY UNION. HOWEVER, FEW REPORTS CURRENTLY EXIST, AND RESOURCES FOR COACHES INTERESTED IN USING A TACTICAL PERIODIZATION APPROACH ARE LIMITED. THIS ARTICLE AIMS TO DEMONSTRATE HOW TACTICAL PERIODIZATION CAN BE APPLIED IN RUGBY UNION TO HELP COORDINATE LONG-TERM PLANNING, IMPROVE THE SPECIFICITY OF TRAINING, AND PREPARE PLAYERS MORE EFFECTIVELY FOR COMPETITION.
Emotional and Social Reactivity as Mechanisms of Stress Generation: A Momentary Assessment Study
Authors: Sears Meredith S. , Niles Andrea N. , Repetti Rena L.
Published: April 2018

Depressed individuals report higher rates of stressful daily interpersonal events. The stress generation hypothesis suggests that traits and behaviors associated with depression may actually cause these stressors to occur. The exact day-to-day emotional and behavioral processes that drive stress generation, however, are less well understood. The present study uses experience sampling methods in a sample of 110 female undergraduate students to examine hour-by-hour emotional and social reactivity and avoidance coping as possible contributors to stress generation. Participants reported on overall symptoms of depression and then completed four daily diaries per day over a five-day period on emotional state, stressful interpersonal experiences, and avoidance behaviors. Multilevel models revealed that emotional distress both generated and was generated by interpersonal stressors such as conflict, rejection, or criticism. Avoidant behavioral responses to stressors—such as social withdrawal, substance use, or ignoring a problem—also significantly contributed to negative mood: Emotional reactivity was thus amplified by problem avoidance. Individuals who reported more depressive symptoms were especially likely to respond to negative moods with avoidance behavior. Ramifications for clinical interventions that focus on reducing emotional reactivity and avoidance coping are discussed.
UMA CRÍTICA À TEORIA DA COMPLEXIDADE PROPOSTA POR EDGAR MORIN
Authors: Andrade Érico
Published: April 2018

O escopo de nosso artigo restringe-se à proposição de uma crítica à teoria da complexidade quanto ao seu pressuposto ontológico: realidade complexa e à inalação decorrente de tal pressuposto; a necessidade de uma ciência da complexidade. Essa crítica visa apontar, por um lado, as insuficiências da referida teoria, marcada por um forte apelo metafísico, quando essa pretende estabelecer um conhecimento a priori e inédito apoiado supostamente num dado empírico ou mais precisamente na complexidade do real. Por outro, nossa crítica tenta desconstruir parte dos argumentos da teoria da complexidade voltados à generalização de certos modelo complexos – empreendidos em alguns ramos do saber científico – enquanto subterfúgio para a constituição de uma teoria geral da ciência. Assim, defendermos a idéia de que quando não retoma pressuposto da tradição metafísica – a ontologia determina a epistemologia; já invalidados porque recorrem ao mythy of given – a teoria da complexidade incorre na grave falhe de determinar o modus operandis da ciência a partir de uma teoria metacientífica, inexeqüível experimentalmente.
A questão da cidadania nos Princípios da Filosofia do Direito de Hegel
Authors: Dela-Savia Sergio Luís Rizzo
Published: April 2018

Este artigo pretende pôr em evidência a expressão conceitual que adquire a figura do cidadão no quadro da filosofia política hegeliana seguindo a exposição político-especulativa dos Princípios da Filosofia do Direito. Veremos que o movimento de figuração da cidadania – mediador das relações entre vida privada/vida pública, sociedade civil/Estado, direitos/deveres – evidencia um dos pontos fortes da ética hegeliana, a saber, que toda ordem política – é indissociavelmente ligada, ao mesmo tempo, aos costumes da sociedade e à atividade lúcida dos indivíduos. A partir dessa perspectiva de análise compreendemos melhor como os Princípios da Filosofia do Direito trazem à maturidade um elemento central do pensamento político moderno: a ideia de que a realização do bem comum repousa sobre a força e a estabilidade das instituições políticas.
VISIBILIDADE DO TRABALHO PESQUEIRO: REQUALIFICAÇÃO DE ESPAÇO PARA COOPERATIVA DE PESCADORES DE JAGUARÃO/RS
Authors: Selbach Jeferson Francisco , Ávila Chiarelli Lígia Maria , Centeno Jane Soares , Ferreira Porto Olimar Jesus
Published: April 2018

Contribuir com a manutenção do trabalho cooperado é fomentar os princípios de autogestão social, economia solidária, reciprocidade e desenvolvimento do fazer comunitário. Os pescadores de Jaguarão (RS) sindicalizados se organizaram em uma Cooperativa para pleitear junto à Prefeitura Municipal a cedência de um galpão para implantar um centro de recebimento de pescados e comercialização da produção. O objetivo da proposta de ação foi contribuir com a visibilidade do trabalho pesqueiro, através de elaboração de proposta de requalificação espacial deste galpão municipal. Pretendeu-se possibilitar ocupação adequada em termos de otimização do espaço. Fez parte da atividade organizar, em colaboração com os futuros usuários, material de campanha de arrecadação junto à comunidade jaguarense, visando aquisição de equipamentos e mobiliário, bem como a reforma pretendida. Foram realizadas: reunião entre a equipe executora e os pescadores para levantamento das demandas de uso do espaço; visita em loco para levantar os principais itens necessários à elaboração de uma proposta de ocupação; elaboração e apresentação da proposta arquitetônica através de pranchas; elaboração do material de campanha. Concluímos que, através de assessoria projetual prestada à Cooperativa, potencializou-se o pleito dos pescadores junto à Prefeitura Municipal para que cedência do galpão, ocorreu a união dos pescadores em torno de um projeto coletivo e a publicização do trabalho pesqueiro para a comunidade jaguarense. A proposta extensionista foi avaliada como pertinente, pois alcançou seus objetivos de realizar o projeto arquitetônico e o material de campanha, bem como em relação à aprendizagem, ao envolver a equipe executora com uma comunidade de baixa renda e contribuir em termos de políticas públicas.
PESQUISA QUALITATIVA: REFLEXÕES GEOGRÁFICAS A PARTIR DE UM ESTUDO DE CASO SOBRE AS CONTRADIÇÕES URBANAS DA CIDADE DE SOROCABA – SP / Qualitative Research: Geographic Considerations from a Case Study on Urban Contradictions of the City of Sorocaba - SP
Authors: Burgos Rosalina
Published: April 2018

Partindo do entendimento acerca da importância dos caminhos metodológicos da pesquisa qualitativa no âmbito da Geografia, e do posicionamento acadêmico e social do pesquisador na definição do tema, método e metodologia de pesquisa, destaca-se a relação intrínseca entre a natureza qualitativa e quantitativa dos fenômenos analisados. Esta reflexão é tecida com base na temática acerca das possibilidades de pensar e agir pelo direito à cidade, tendo como estudo de caso o processo recente de valorização e segregação espacial da cidade de Sorocaba.Palavras chave: pesquisa qualitativa, valorização espacial, segregação espacial, direito à cidade, cidade de Sorocaba. ABSTRACTBased on the understanding of the importance of methodology of qualitative research in Geography, and academic and social position of the researcher in the theme definition, method and research methodology, in the relationship between qualitative and quantitative analysis on the essence of phenomena. This reflection is based on the theme of the possibilities of thinking and acting for the right to the city, taking as a case study the recent process of spatial valorization of the city of Sorocaba.Key words: qualitative research, valorization of the space, spatial segregation, the right to the city, city of Sorocaba
GÊNESE DE BARRAS DE SOLDAMENTO E SUAS CARACTERÍSTICAS MORFOLÓGICAS: ALTO RIO PARANÁ, BRASIL / Attachment Bars Genesis and Morphological Features: Upper Paraná River, Brazil
Authors: Dos Santos Vanessa Cristina , Stevaux José Cândido
Published: April 2018

O rio Paraná, em seu trecho natural, é caracterizado por canais secundários de diferentes ordens de tamanho, separando diversas ilhas e barras fluviais. As barras fluviais apresentam grande porte e suas formas mudam constantemente conforme a magnitude do fluxo. Este estudo apresenta a caracterização morfológica de uma barra de soldamento e suas adjacências, situadas junto à ilha Santa Rosa, no alto rio Paraná. Para tanto, a morfologia da barra foi comparada em dois momentos hidrológicos distintos através de levantamentos com aparelho de batimetria. Os resultados evidenciam que a morfologia da barra estudada está diretamente influenciada pelas oscilações da vazão do rio Paraná. No período de águas altas há maior retrabalhamento da forma, e preservação parcial em período de águas médias. A análise da distribuição das formas adjacentes à barra de soldamento permitiu constatar que o canal principal possui mais energia, já que apresenta formas íngremes e profundas, e o canal secundário indica menor energia de fluxo por apresentar formas mais suaves.AbstractThe Paraná River, in its natural reach is characterized by secondary channels of different size orders, which separates several islands and bars. Fluvial bars are large and their forms change constantly due to the flow. This study presents the morphological characterization of an attachment bar and its adjacencies, located nearby the island Santa Rosa, in the upper Paraná River. Therefore, the morphology of the bar was compared in two distinct hydrological moments through surveys with bathymetry equipment. The results indication that the morphology of the studied bar is directly influenced by fluctuations in the flow of the Paraná River. In the period of high water level there is more reworking of the forms and partial preservation in average water level. The analysis of the distribution of forms adjacent to the attachment bar allowed establishing that the main channel is more energetic, as it presents abrupt and deep forms and the secondary channel indicates lower energy flow by presenting smoother forms.Keywords:Paraná River, Fluvial Geomorphology, Morphology, Attachment Bar
Georg Simmel e a crítica à objetividade do conhecimento
Authors: Canella Murilo
Published: April 2018

Este artigo propõe a análise da crítica à objetividade do conhecimento efetuada por Georg Simmel. Dessa delimitação deriva a densa síntese teórica condensada nesse tema, uma vez que ele se apresenta de forma fragmentada – mas não negligenciada – ao longo de sua obra. A temática da crítica à objetividade do conhecimento perpassa o jovem e o maduro Simmel; o eixo teórico desloca-se do domínio metaconceitual do qual a sociologia formal nutre-se, à esfera metodológica do relacionismo e aos processos empíricos simultâneos que concatenam a realidade social. Este estudo pretende analisar a crítica referida, num primeiro momento, e, posteriormente, intenta relacionar e demonstrar o vínculo conceitual existente entre a crítica e outros dois complexos conceituais basais em Simmel, a cultura e o individualismo. A metodologia refere-se, portanto, à análise da crítica à objetividade do conhecimento sistematizada no texto tardio A lei individual, publicado em 1913 na revista Logos, e sua relação teórica substancial com o domínio da cultura e sua expressão no individualismo.
A multidimensionalidade da sustentabilidade: percepções em um agroecossistema de base familiar característico de assentamentos de reforma agrária.
Authors: Marques Andersson Norberto Luiz , Noronha Ana Paula , De Ávila Dante Trindade , Costa Jakes Halan de Queiroz , Casalinho Hélvio Debli
Published: April 2018

Este trabalho faz-se relevante por desenvolver a temática da multidimensionalidade da sustentabilidade em agroecologia, onde este diferencial manifesta uma alternativa de produção livre de agrotóxico, melhorando a qualidade de vida do produtor, da sua família que se abastece de sua produção, bem como de seus consumidores. Ações estas que se alinham com a proposta de desenvolvimento rural sustentável, baseada na sustentabilidade do agroecossistema. O objetivo foi apreciar, na forma exploratória, a muldimensionalidade da sustentabilidade em uma propriedade agrícola familiar do sul do Rio Grande do Sul, a partir de uma visita realizada em um lote de produção de base agroecológica, no Assentamento Conquista da Liberdade, no município de Piratini - RS. Trata-se, portanto, de pesquisa exploratória. No desenvolvimento das atividades foram utilizadas ferramentas/instrumentos denominadas de metodologias participativas envolvendo uma observação participante, como uma ferramenta de diagnóstico rural participativo, denominada de caminhada, auxiliada por técnica de reunião problematizadora, complementada por entrevista semiestruturada. Ações estas viabilizadas no decorrer do mês de fevereiro de 2013. Como conclusão, temos que os agricultores familiares na propriedade estudada indicam e caracterizam o sistema de produção como de base ecológica apresentando os seguintes atributos: adaptabilidade, estabilidade, produtividade, resiliência, complexidade, equidade e autogestão. Observa-se uma preocupação na continuidade da busca da sustentabilidade deste agroecossistema, denotando-se uma referência com o social, com o ambiental, com o econômico, com o cultural, com o político e com o ético.
Análise de viabilidade econômica na implantação de uma agroindústria de produção e processamento de cogumelos
Authors: Heiden Guilherme , Gomes Silva da Luz Maria Laura , Gadotti Gizele Ingrid , Silveira da Luz Carlos Alberto , Maciel Silva Augusto Henrique , Monteiro Rita , Cassalho Matheus , Nascimento Rocha Gean , Maldaner Vanessa
Published: April 2018

A produção de cogumelos em ambiente protegido é parte de um sistema de produção agrícola especializado, que possibilita o controle e caz de condições edafoclimáticas sem negligenciar o planejamento da produção, dos custos e do mercado. O trabalho teve o objetivo de planejar uma agroindústria de produção de cogumelos que produza duas variedades: L. edodes e A. bisporus e analisar a sua viabilidade técnica-econômica em um sistema de produção em estufas de ambiente controlado. Uma pesquisa de mercado mostrou que uma produção mensal de 400 quilogramas de cogumelos poderia abastecer o comércio local de Pelotas e Porto Alegre, com cogumelos desidratados e in natura. Foi realizada uma análise econômica em cinco cenários, que gerou índices nanceiros, tais como TIR (Taxa Interna de Retorno), VPL (Valor Presente Líquido), TIRm (Taxa Interna de Retorno Modi cada) e payback, comparando-as com uma TMA (Taxa Mínima de Atratividade) de 10,20%. A partir da análise dos cenários concluiu-se que é necessário aumentar a produção para 1224 quilogramas por mês e/ ou praticar preços pelo menos 20% acima daqueles de mercado para obter condições de viabilidade econômica. Nestas condições, os melhores cenários apresentaram payback de 4 e 6 anos.
Effects of insulin, insulin-like growth factor-II, and nerve growth factor on neurite formation and survival in cultured sympathetic and sensory neurons
Authors: Recio-Pinto E , Rechler MM , Ishii DN
Published: April 2018

Insulin and the insulin-like growth factors (IGFs) may directly affect the development of the nervous system. NGF, IGF-II, and insulin's effects on neurite formation and neuronal survival were studied in peripheral ganglion cell cultures from chick embryos. Neurite outgrowth was enhanced in a dose-dependent manner by insulin and IGF-II in sympathetic cell cultures. The half-maximally effective concentration, ED50, was about 0.4-0.6 nM for both polypeptides, and concentrations as low as 10 pM were active. However, in sensory neurons the ED50 for neurite outgrowth was about 30 nM for insulin and 0.1 nM for IGF-II, suggesting that these factors may have selective effects in different neuronal tissues. Neither serum nor the presence of non-neuronal cells was required for the response in sympathetic neurons. The specific anti- NGF antiserum inhibited the neurite outgrowth response to NGF but not to insulin nor IGF-II. Insulin and IGF-II additionally supported survival of sensory and sympathetic neurons; however, insulin was not as efficacious as NGF. The combination of high concentrations of NGF and insulin was no better than NGF alone in supporting sympathetic cell survival, or neurite outgrowth. This indicates that insulin acts on the same, or a subpopulation, of NGF-responsive neurons. These results support the hypothesis that insulin and its homologs belong to a broad family of neuritogenic polypeptides.
Multiple calcium-activated neutral proteinases (CANP) in mouse retinal ganglion cell neurons: specificities for endogenous neuronal substrates and comparison to purified brain CANP
Authors: Nixon RA , Quackenbush R , Vitto A
Published: April 2018

Calcium-activated neutral proteinases (CANPs) and their specificities for axonally transported proteins were studied within intact axons of mouse retinal ganglion cell (RGC) neurons in vitro. Two CANP activities with markedly different properties were identified. CANP B, at endogenous calcium levels, selectively cleaved the 145,000 Da (145 kDa) neurofilament protein subunit to yield 143 and 140 kDa neurofilament proteins that are also major constituents of the axonal cytoskeleton. This process represents a posttranslational modification of the neurofilament protein subunit rather than the initial step in its degradation (Nixon et al., 1982, 1983). A second calcium-activated neutral proteinase activity, CANP A, appeared only when calcium levels in the incubating medium were 100 microM or higher. CANP A degraded most proteins in RGC axons but acted considerably more rapidly on high- molecular-weight species. In particular, a 290–320 kDa protein in the Group IV (SCb) phase of axoplasmic transport was degraded 3 X faster than other major axonal proteins, including neurofilament proteins and fodrin. When maximally expressed, CANP A activity represented an enormous proteolytic potential in RGC axons--more than 50% of the total axonal content of proteins larger than 60 kDa could be hydrolyzed within 5 min. The calcium requirements, inhibitor profile, and substrate specificity of CANP A were similar to those of mCANP, the major CANP of mouse brain purified to homogeneity, suggesting that these enzymes may be the same or highly related proteins. The existence in a single neuron type of two CANP activities with markedly different substrate specificities and enzymatic properties emphasizes the possible functional diversity of calcium-activated neutral proteinases in neurons. These functions include the posttranslational modification, as well as degradation of neuronal proteins.
Orientation selectivity of synaptic potentials in neurons of cat primary visual cortex
Authors: Ferster D
Published: April 2018

Neurons of the visual cortex of the cat were penetrated with intracellular electrodes and postsynaptic potentials evoked by visual stimuli recorded. By alternately polarizing the cell with steady current injected through the recording electrode, IPSPs and EPSPs could be recorded and analyzed independently. Hyperpolarizing current suppressed IPSPs and enhanced EPSPs by moving the membrane potential toward the IPSP equilibrium potential. Depolarizing the cell toward the EPSP equilibrium potential enhanced IPSP. The responses to electrical stimulation of the LGN, where EPSPs and IPSPs could be distinguished easily by virtue of their characteristic latencies and shapes, were used to set the current injection to the appropriate level to view the two types of synaptic potential. EPSPs were found to be well oriented in that maximal depolarizing responses could be evoked at only one stimulus orientation; rotating the stimulus orientation in either direction produced a fall in the EPSP response. IPSPs were also well tuned to orientation, and invariably the preferred orientations of EPSPs and IPSPs in any one cell were identical. In addition, no systematic difference in the width of tuning of the two types of potential was seen. This result has been obtained from penetrations of over 30 cortical cells, including those with simple and complex receptive fields It is concluded that orientation of cortical receptive fields is neither created nor sharpened by inhibition between neurons with different orientation preference. The function of inhibition evoked simultaneously with excitation by optimally oriented stimuli has yet to be determined, though it is likely to be the mechanism underlying other corticalreceptive field properties, such as direction selectivit and end-stopping.
Amplitude modulation of the soleus H-reflex in the human during walking and standing
Authors: Capaday C , Stein RB
Published: April 2018

Experiments were done to determine the amplitude of the monosynaptically mediated H-reflex of the soleus muscle at various phases of the step cycle, using a computer-based analysis procedure. In all subjects tested the amplitude of the H-reflex was strongly modulated in amplitude during the walking cycle and was highest during the stance phase. In many subjects the peak reflex amplitude occurred at about the same time as the peak soleus electromyographic (EMG) activity, but in others it occurred earlier. The form of the reflex variation (i.e., envelope of H-reflex amplitude versus phase in cycle) during the step cycle could also be quite different from that of the EMG produced during stepping. At an equal stimulus strength and EMG level, the H-reflex was always much larger, up to 3.5 X, during steadily maintained contractions while standing than during walking. The large reflexes when subjects were standing are consistent with the control of position required to maintain a stable posture in this task. Similarly, the reflexes during walking are greatest during the stance phase, when they will assist in maintaining the upright position of the body against gravity. The reflexes are smallest during the swing phase when they would oppose ankle flexion. However, since the reflex amplitude is task-dependent (i.e., greater during standing than during walking at the same EMG and stimulus levels) and is not always closely related to the EMG produced during a given task such as walking, the strong modulation of H-reflex during walking is not simply a passive consequence of the alpha-motoneuron excitation level.(ABSTRACT TRUNCATED AT 250 WORDS)
Anatomical and physiological development of the Xenopus embryonic motor system in the absence of neural activity
Authors: Haverkamp LJ
Published: April 2018

Embryos of Xenopus laevis were continually immobilized by immersion in solutions of either chloretone or lidocaine, from the late neural-fold stage to the approximate time of hatching. Such treatment has been shown to result in only transient quantitative effects on swimming behavior. Chronic immobilization was without either immediate or long- term effect on the ventral root output exhibited during “fictive” swimming episodes. Development under these conditions of diminished or absent neural activity similarly had no effects on a number of measures of the size and complexity of motoneuron dendritic arborizations. These results support the premise that the early development of specific neuronal morphology and connectivity may be largely independent of functional activity.
Characterization of the binding and internalization of tetanus toxin in a neuroblastoma hybrid cell line
Authors: Staub GC , Walton KM , Schnaar RL , Nichols T , Baichwal R , Sandberg K , Rogers TB
Published: April 2018

Tetanus toxin is known to bind neuronal tissue selectively. To study the interactions of this potent neurotoxin in an intact cell system, the binding of 125I-tetanus toxin was characterized in a neuroblastoma retina hybrid cell line, N18-RE-105. The binding of 125I-tetanus toxin to membranes prepared from N18-RE-105 cells showed many similarities to the interactions of 125I-toxin with rat synaptic membranes. The binding was decreased with increasing temperature, ionic strength, and pH. 125I- Toxin bound to membranes with high affinity: KD = 0.62 +/- 0.05 nM; Bmax = 196 +/- 45 pmol/mg protein. Quantitative thin-layer chromatography and acid-degradation analysis revealed that N18-RE-105 cells contained polysialogangliosides GD1a and GT1b in high concentrations. An assay was developed to quantitate surface-bound and internalized 125I-tetanus toxin by exploiting the observation that surface-bound 125I-toxin is susceptible to pronase digestion. When cells were incubated with 125I-tetanus toxin at 0 degree C, all of the bound 125I-toxin could be degraded with pronase. In contrast, when the incubations were performed at 37 degrees C, within 10 min about 50% of the total cell-associated 125I-toxin was pronase-resistant. Temperature pulse experiments demonstrated that 125I-tetanus toxin that was bound to cells at 0 degree C rapidly disappeared from the surface when the cells were warmed to 37 degrees C, as revealed by the appearance of pronase-resistant radioactivity. This internalization was sensitive to metabolic inhibitors.(ABSTRACT TRUNCATED AT 250 WORDS)
An experimental analysis of the origins of somatostatin-like immunoreactivity in the dentate gyrus of the rat
Authors: Bakst I , Avendano C , Morrison JH , Amaral DG
Published: April 2018

In previous studies, fibers demonstrating somatostatin-like immunoreactivity were observed in the outer half of the molecular layer of the dentate gyrus in the rat and monkey. They occupy the same region as those of the perforant pathway that originates in the entorhinal cortex. Numerous somatostatin immunoreactive neuronal cell bodies were also observed in the hilar region, though stained axonal profiles could not be followed from these cells into the molecular layer. In the present study, several experimental procedures were employed to determine the origin of the somatostatin-positive fibers in the molecular layer. Transection of the perforant path fibers resulted in such characteristic changes as shrinkage of the molecular layer and sprouting of AChE-positive fibers. There was no apparent decrease, however, in the density of somatostatin-positive fibers. In fact, since the stained fibers occupied a narrower band in the shrunken molecular layer, their density appeared greater. Injections of kainic acid into the hilar region produced a lesion of hilar neurons, including those positive for somatostatin. In the region of cell loss, there was a marked reduction of somatostatin-immunoreactive fibers in the ipsilateral molecular layer, with no detectable changes in the homotopic contralateral molecular layer. The distribution of AChE fibers, which presumably have an extrinsic origin, was not altered by the treatment. In a final series of experiments, the retrograde tracer wheat germ agglutinin-horseradish peroxidase (WGA-HRP) was injected into the hilar region and sections were prepared for the simultaneous demonstration of the tracer and of somatostatin-like immunoreactivity. Somatostatin-positive neurons demonstrating WGA-HRP reaction product were observed primarily in the ipsilateral hilar region, but a few double-labeled cells were also seen in the same area of the contralateral side. These studies indicate that a population of intrinsic neurons located in the polymorphic layer of the dentate gyrus projects to the outer half of the ipsilateral molecular layer. A similar, but very much smaller, projection also extends to the contralateral dentate gyrus. Taken together, these projections appear to account for much of the somatostatin-like immunoreactivity in the molecular layer of the dentate gyrus.
DARPP-32, a dopamine- and adenosine 3':5'-monophosphate-regulated phosphoprotein: regional, tissue, and phylogenetic distribution
Authors: Hemmings HC , Greengard P
Published: April 2018

Rabbit antisera and mouse monoclonal antibodies have been prepared to bovine DARPP-32 (dopamine- and adenosine 3':5'-monophosphate-regulated phosphoprotein, Mr = 32,000), and used to study its regional, tissue, and phylogenetic distributions. The antibodies, none of which distinguished between dephospho-DARPP-32 and phospho-DARPP-32, were characterized and used to develop a sensitive and specific radioimmunoassay for DARPP-32. The radioimmunoassay, in conjunction with immunolabeling of SDS/PAGE transfers and immunoprecipitation of phosphorylated tissue extracts, was used to measure immunoreactive DARPP-32 in microdissected regions of rat CNS, in peripheral nervous and non-nervous tissues, and in CNS tissue from various animal species. The distribution of DARPP-32 was generally consistent with the interpretation that it is localized primarily to dopaminoceptive cells that possess dopamine-sensitive adenylate cyclase (D-1 dopamine receptors coupled to adenylate cyclase). Within the rat CNS, DARPP-32 was most highly concentrated in the basal ganglia. DARPP-32 was present in neostriatum from all six mammalian species tested (mouse, rat, guinea pig, rabbit, cow, and rhesus monkey) at concentrations of from 96 to 144 pmol/mg total protein, which constituted from 0.22 to 0.32% of the total protein. DARPP-32 was also identified at low levels in several peripheral tissues, including choroid plexus, parathyroid cells, adrenal chromaffin cells, posterior pituitary gland, pineal gland, and superior cervical sympathetic ganglion. A phylogenetic survey was carried out of proteins immunologically related to DARPP-32 in nervous tissue from nonmammalian species. DARPP-32-like proteins were identified in dopaminoceptive brain regions from representative members of the amniote vertebrate classes (birds and reptiles), while none was identified in dopaminoceptive brain regions from representative members of the anamniote vertebrate classes (bony fishes and amphibians) or in nervous tissue from representative members of several invertebrate classes.
Development of serotonin-containing neurons in Drosophila mutants unable to synthesize serotonin
Authors: Valles AM , White K
Published: April 2018

We have initiated a study of the CNS of mutant Drosophila melanogaster larvae carrying a genetic deletion of the gene Ddc that encodes the enzyme dopa decarboxylase (DDC). The two major objectives of this study were (1) to ascertain that the DDC encoded by the gene Ddc was the only decarboxylase utilized in serotonin (5HT)-containing neurons and (2) to determine the effect of DDC deficiency on the development of 5HT- immunoreactive neurons. CNSs of wild-type larvae and of larvae genetically deficient for the gene Ddc were processed for serotonin immunocytochemistry using a monoclonal antibody against 5HT. The pattern of 5HT immunoreactivity in the wild-type and the Ddc-deficient CNS is compared. In contrast to the wild-type, 5HT immunoreactivity is absent in the Ddc-deficient CNSs. The lack of immunocytochemically detectable 5HT in the mutant CNSs is consistent with the idea that the DDC encoded by the gene Ddc is utilized in 5HT-containing neurons. To study the development of neurons committed to the 5HT differentiation pathway in the absence of 5HT, we used a second biochemical property characteristic of 5HT-containing neurons, the ability to take up 5HT. CNSs from mutant animals were incubated in exogenous 5HT and the accumulated 5HT detected immunocytochemically. Neurons capable of selective 5HT uptake were present in the mutant CNSs in the same pattern as the 5HT-immunoreactive neurons in the wild-type CNS. This result suggests that the presumed inability to synthesize 5HT does not preclude differentiation of other normal biochemical properties of 5HT- containing neurons.
Analysis and isolation of embryonic mammalian neurons by fluorescence- activated cell sorting
Authors: St. John PA , Kell WM , Mazzetta JS , Lange GD , Barker JL
Published: April 2018

Cells were dissociated from the CNS of the embryonic mouse and rat to produce cell suspensions suitable for analysis and separation on a fluorescence-activated cell sorter (FACS). Cells from the spinal cord of the embryonic mouse were analyzed in the most detail. Cell suspensions generated three major peaks in histograms of forward-angle light scatter. Examination of material isolated from each peak and labeling of cell suspensions with the nonvital and supravital fluorescent dyes propidium iodide, ethidium bromide, and acridine orange demonstrated that the three peaks represented live cells, dead cells, and subcellular fragments. Passage through the cell sorter did not detectably damage live cells, as shown by light microscopy, FACS analysis, and in vitro culture of sorted cells. Neurons and glial cells collected by sorting survived at least 4 weeks in culture. Cell suspensions dissociated from the dorsal root ganglia, hippocampus, hypothalamus, cerebellum, and cerebral cortex of the embryonic mouse and from the spinal cord of the embryonic rat produced similar results. Analysis of samples prepared at different developmental stages showed that viable cells could be recovered from each of these regions throughout the important stages of neurogenesis and early cellular differentiation, but that few viable cells could be recovered from animals beyond late embryonic or early postnatal ages. Quantitative FACS analysis of monoclonal antibody A2B5, tetanus toxin and cholera toxin, and lectins binding to live dissociated cells from the embryonic spinal cord demonstrated that these cells had already developed binding sites for these cell-surface ligands by embryonic day 13. These results demonstrate that a fluorescence-activated cell sorter can be used for quantitative analysis of specific cellular properties, that FACS analysis and sorting can be used to identify and isolate live cells from many regions of the embryonic mammalian CNS during important developmental periods, and that sorted neurons and glial cells can be maintained for weeks in culture.
Identification of the neural pathway for reinforcement of feeding when Aplysia learn that food is inedible
Authors: Schwarz M , Susswein AJ
Published: April 2018

Bilateral sectioning of the esophageal nerves that innervate the gut of Aplysia was found to have profound effect on response decrement to inedible food: Time to criterion for cessation of feeding was elevated, no memory of the decrement was present 24 hr after training, and motor patterning during training was altered. The parametric features of response decrement to sustained lip stimulation were examined to determine their resemblance to parameters of response decrement to inedible food after esophageal nerve sectioning. Parameters of response decrement were similar, indicating that after esophageal nerve sectioning response decrement is likely to be the result of sustained lip stimulation. Bilateral nerve sectioning had no effect on decrement due to sustained lip stimulation. Unilateral lesions and lesions of either of the two major divisions of the esophageal nerves had no effect on learning that food was inedible. The data indicate that bilateral nerve sectioning eliminates all stimuli causing negative reinforcement of feeding due to failure to consume food. Based on the data in this and the previous paper, a model is presented suggesting sites of action and mechanisms for learning that foods are edible or inedible in Aplysia.
Localization and development of nerve growth factor-sensitive rat basal forebrain neurons and their afferent projections to hippocampus and neocortex
Authors: Koh S , Loy R
Published: April 2018

In order to understand further the role of NGF in the development of NGF-sensitive basal forebrain neurons and their afferent connections to the hippocampus and neocortex, we have used monoclonal antibody 192 IgG to detect and localize NGF receptors immunocytochemically in the developing rat brain. NGF receptor immunoreactivity (NGF-RI) is first visible at embryonic day 13 (E 13) in the ventrolateral telencephalic wall and follows a caudal-to-rostral gradient in its initial appearance. NGF-RI neuronal number and neuropil staining undergo substantial increases before birth, and extensive dendritic growth and increases in perikaryal size continue during the first 3 weeks of postnatal life. This growth and cellular differentiation, however, is followed in the fourth postnatal week and later by an apparent decrease in dendritic arborization and 50% shrinkage in the size of perikarya. Initial NGF-RI fiber outgrowth from immature basal forebrain neurons directed toward appropriate target fields is observed as early as E 15. The formation of a laminar pattern by septal axons in the hippocampal terminal fields and invasion of NB afferents into the cortex occur postnatally over a protracted time. In the hippocampus, NGF-RI is initially diffusely distributed, and wide bands of immature granule and pyramidal cells are almost devoid of immunoreactive fibers; however, with maturity, septal axon terminals become concentrated in narrow zones closely associated with the cellular layers. In the neocortex, early-arriving basal forebrain afferents accumulate in the intermediate zone underneath the darkly immunoreactive subplate before they enter The cortex. Dense subplate and transiently present, radially aligned fiber staining completely disappear in later postnatal week and are gradually replaced by specific axonal and terminal staining associated with NB afferents. The expression of NGF receptor in the subplate zone at the time afferents arrive and its subsequent disappearance with the specific terminal formation suggest that NGF receptor and concomitant accumulation of NGF in the subplate may act as a temporary target for the early-arriving basal forebrain afferents; ingrowing afferents may then be guided by radially oriented NGF-RI fibers to proper synaptic sites.
SCP-containing R20 neurons modulate respiratory pumping in Aplysia
Authors: Alevizos A , Weiss KR , Koester J
Published: April 2018

Respiratory pumping in Aplysia consists of transient, synchronous pumping actions of the gill, siphon, mantle shelf, and parapodia. This behavior has previously been shown to be driven by a network of coupled interneurons in the abdominal ganglion, the R25 and the L25 cells. We describe here a pair of electrically coupled cells, the R20 cells, which when active can initiate respiratory pumping or increase its spontaneous rate of occurrence. This action is mediated by a slow, long- lasting excitation of the endogenous burst mechanism of the cells in the R25/L25 network. The R20 cells, which are located in the abdominal ganglion, also make slow inhibitory connections to the RB cells and to the RG cells in that ganglion, and to the gill motoneurons in the branchial ganglion. The R20 cells are immunoreactive to SCPB, a molluscan neuropeptide. Biochemical purification studies demonstrate that each of the R20 cells synthesizes not only SCPB, but also SCPA, a closely related molecule known to be encoded by the same gene as SCPB. The R20 cells also synthesize in abundance several other low-molecular- weight, methionine-containing peptides. The excitatory actions of the R20 cells on the R25/L25 network are mimicked by SCPA and SCPB. However, the inhibitory actions of the R20 cells on the RB cells, the RG cells, and on the cells of the branchial ganglion are not mimicked by the SCPs. Thus, the data support the hypothesis that the R20 cells release SCPA and SCPB and at least one other unidentified transmitter.
Integration of distributed cortical systems by reentry: a computer simulation of interactive functionally segregated visual areas
Authors: Finkel LH , Edelman GM
Published: April 2018

A computer model based on visual cortex has been constructed to analyze how the operations of multiple, functionally segregated cortical areas can be coordinated and integrated to yield a unified perceptual response. We propose that cortical integration arises through the process of reentry--the ongoing, parallel, recursive signaling between separate maps along ordered anatomical connections. To test the efficacy of this reentrant cortical integration (RCI) model, we have carried out detailed computer simulations of 3 interconnected cortical areas in the striate and extrastriate cortex of the macaque. The simulated networks contained a total of over 222,000 units and 8.5 million connections. The 3 modeled areas, called VOR, VOC, and VMO, incorporate major anatomical and physiological properties of cortical areas V1, V3, and V5 but are vastly simplified compared with monkey visual cortex. Simulated area VOR contains both orientation and directionally selective units; simulated area VMO discriminates the direction of motion of arbitrarily oriented objects; and simulated area VOC responds to both luminance and occlusion boundaries in the stimulus. Area VOC is able to respond to illusory contours (Kanizsa, 1979) by means of the same neural architecture used for the discrimination of occlusion boundaries. This architecture also generates responses to structure-from-motion by virtue of reentrant connections from VMO to VOC. The responses of the simulated networks to these illusions are consistent with the perceptual responses of humans and other species presented with these stimuli. The networks also respond in a consistent manner to a novel illusion that combines illusory contours and structure-from-motion. The response synthesized to this combined illusion provides a strong argument supporting the need for a recursive reentrant process in the cortex. Functional integration of the simulated areas in the RCI model were found to depend upon the combined action of 3 reentrant processes: (1) conflicting responses among segregated areas are competitively eliminated, (2) outputs of each area are used by other areas in their own operations, and (3) outputs of an area are “reentered” back to itself (through lower areas) and can thus be used iteratively to synthesize responses to complex or illusory stimuli. Transection of the reentrant connections selectively abolished these integrative processes and led to failure of figural synthesis. The proposed model of reentry suggests a basis for understanding how multiple visual areas as well as other cortical areas may be integrated within a distributed system.
Quantitative physiological characterization of a quinoxalinedione non- NMDA receptor antagonist
Authors: Yamada KA , Dubinsky JM , Rothman SM
Published: April 2018

The effects of 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, or FG 9065) on excitatory amino acid responses in cultured neurons from rat hippocampus were studied using tight-seal whole-cell recording techniques. CNQX reduced the magnitude of peak inward currents produced by exogenously applied kainate, quisqualate, and N-methyl-D-aspartate (NMDA) with Ki's of 2.5, 3.5, and 96 microM, respectively. The antagonism was competitive against kainate and quisqualate, but noncompetitive against NMDA. Glycine markedly reduced CNQX antagonism of NMDA responses. The same recording technique using pairs of monosynaptically connected neurons demonstrated reversible diminution of excitatory postsynaptic potentials in 7 of 7 pairs, using CNQX at concentrations as low as 10 microM. CNQX applied alone did not evoke inward or outward currents at membrane potentials near the resting membrane potential and did not affect the current-voltage relationship at membrane potentials between -90 and -30 mV. These observations represent the first quantitative characterization of glutamate receptor antagonism by CNQX with respect to physiological rather than biochemical parameters and demonstrate that CNQX is far more potent and more selective than currently available non-NMDA antagonists. The results suggest that CNQX will be a useful pharmacologic tool for the study of synaptic transmission in a variety of systems in which glutamate or related excitatory amino acids are involved.