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1.
An Acad Bras Cienc ; 95(suppl 1): e20220532, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37556713

RESUMO

This study evaluated the technological viability of yogurt with the addition of green-banana biomass (Musa spp.) considering the resistant starch (BBV) as a potential prebiotic ingredient and texture agent. Four yogurt formulations were prepared: control; 3% BBV; 5% BBV; and 10% BBV. They were subjected to analysis of resistant starch, lactose, fat, total dry extract, defatted dry extract, moisture, ash, proteins, pH and titratable acidity; syneresis analysis, instrumental texture and instrumental color. All four formulations met the requirements of the identity and quality regulation for fermented milks regarding the physicochemical and microbiological parameters. In the instrumental color analysis, in all treatments with added BBV, darkening was observed after 21 days, with a reduction of a* coordinate and an increase of b* coordinate. In the instrumental texture analysis, the yogurt in the Control treatment had the highest firmness (0.430 N) at 21 days among these treatments. Among the treatments with added BBV, the yogurt with 5% added BBV showed the best results for increasing the viability of lactic bacteria. It was found that yogurt with added BBV is a promising alternative in the elaboration of functional dairy products, adding value to the banana production chain by reducing the green fruit waste.


Assuntos
Musa , Prebióticos , Biomassa , Prebióticos/análise , Amido Resistente/análise , Iogurte/análise
2.
An Acad Bras Cienc ; 92(3): e20190155, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33053106

RESUMO

The suckling behavior of piglets was evaluated in summer and winter, using 21 sows of the same genetic line. Data were collected in July (winter) and in January (summer). The experimental design was a randomized complete block (age of piglets) in a 2x2 factorial scheme, with season of the year (winter and summer) and shift (day, from 06 h to 1h:59min and night from 18h to 05h:59min) as factors. The behavioral variables analyzed were number, interval, and frequency of suckling. The behaviors were monitored on day 7 and 15 of lactation, for 24 hours. In winter, the farrowing room had a mean temperature of 20.32 ±2.17°C and a relative humidity (RH) of 58.63 ±2.99%. In the summer, the mean temperature was 26.65 ±4.02°C, with an RH of 62.22 ±12.06%. During winter, the piglets presented longer sucklings during the night, dedicating 1.84 minutes more to suckling compared to the daytime. Nighttime sucklings were 3.13 minutes longer in winter than in summer. However, in summer, piglets suckled more often during the night, with greater interval between feeds during the day. Based on our results, the season influences the suckling behavior of piglets, with shorter feedings and greater frequencies in summer.


Assuntos
Lactação , Suínos , Animais , Feminino , Estações do Ano , Suínos/fisiologia , Temperatura
3.
An Acad Bras Cienc ; 90(4): 3675-3683, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30517220

RESUMO

The objective of this trial was to evaluate the behavioral patterns and performance of lactating sows and their litters under the effect of artificial vocalization. Twenty-eight sows and their litters were distributed in a completely randomized design in a 2x2 factorial scheme (artificial vocalization x lactation week). The behavior of the animals was monitored during 24 hours on the 7th and 15th days of lactation, analyzing the number, interval, and frequency of nursings. The body condition and performance of the sows were also evaluated. Artificial vocalization promoted higher frequencies of eating for sow and nursing for piglets (P <0.05), increased inactive sow behavior (P <0.05), and reduced sow alert in activity (P <0.05). The number and duration of suckling sessions at the 15thday of lactation were reduced (P <0.05). The use of artificial vocalization did not affect the body condition or milk production of the lactating sows, or the performance of the litter during lactation (P> 0.05). The use of maternal artificial vocalization during lactation of sows promoted greater lactation efficiency and longer rest time, favoring the sows' welfare.


Assuntos
Animais Lactentes/fisiologia , Comportamento Animal/fisiologia , Lactação/fisiologia , Comportamento Materno/fisiologia , Suínos/fisiologia , Vocalização Animal , Animais , Feminino , Fatores de Tempo
4.
J Phys Ther Sci ; 27(6): 1645-8, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26180289

RESUMO

[Purpose] This study aimed to evaluate the anti-inflammatory and analgesic effects of intraoral application of low-level laser therapy (660 nm) to control pain, swelling and interincisal opening following the extraction of mandibular third molars. [Subjects and Methods] Ten patients underwent removal of lower third molars using the same surgical protocol and pharmacological approach. In the postoperative period, all patients received four consecutive daily sessions of low-level laser therapy, beginning 24 hours after the surgery. Intraoral applications using the diode laser with 660 nm wavelength in the continuous scan mode were performed covering the entire surgical area, which was divided into four quadrants, each of 1 cm(2) area at a distance of 1 cm. The energy applied at each point was 5 J/cm(2) during 8 seconds. [Results] The swelling and interincisal opening returned to normal 24 hours after the first low-level laser therapy application (Friedman test). Moreover, the pain intensity was reduced on the third postoperative day, according to the Friedman test. [Conclusion] Low-level laser therapy (660 nm), at the dosimetry used in this study, was effective in reducing postoperative pain and swelling following oral surgery.

5.
J Neurosci ; 33(30): 12218-28, 2013 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-23884930

RESUMO

The neural mechanisms that support the late postnatal development of spatial navigation are currently unknown. We investigated this in rats and found that an increase in the duration of AMPAR-mediated synaptic responses in the hippocampus was related to the emergence of spatial navigation. More specifically, spontaneous alternation rate, a behavioral indicator of hippocampal integrity, increased at the end of the third postnatal week in association with increases in AMPAR response duration at SC-CA1 synapses and synaptically driven postsynaptic discharge of CA1 pyramidal neurons. Pharmacological prolongation of glutamatergic synaptic transmission in juveniles increased the spontaneous alternation rate and CA1 postsynaptic discharge and reduced the threshold for the induction of activity-dependent synaptic plasticity at SC-CA1 synapses. A decrease in GluA1 and increases in GluA3 subunit and transmembrane AMPAR regulatory protein (TARP) expression at the end of the third postnatal week provide a molecular explanation for the increase in AMPAR response duration and reduced efficacy of AMPAR modulators with increasing age. A shift in the composition of AMPARs and increased association with AMPAR protein complex accessory proteins at the end of the third postnatal week likely "turns on" the hippocampus by increasing AMPAR response duration and postsynaptic excitability and reducing the threshold for activity-dependent synaptic potentiation.


Assuntos
Região CA1 Hipocampal/crescimento & desenvolvimento , Região CA1 Hipocampal/fisiologia , Aprendizagem em Labirinto/fisiologia , Receptores de AMPA/fisiologia , Percepção Espacial/fisiologia , Fatores Etários , Animais , Canais de Cálcio/fisiologia , Eletrofisiologia , Potenciais Evocados/fisiologia , Potenciais Pós-Sinápticos Excitadores/fisiologia , Feminino , Masculino , Plasticidade Neuronal/fisiologia , Técnicas de Cultura de Órgãos , Oxazinas/farmacologia , Ratos , Ratos Long-Evans , Receptores de AMPA/agonistas , Sinapses/fisiologia
6.
J Chem Neuroanat ; 137: 102415, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38521203

RESUMO

Over time, the body undergoes a natural, multifactorial, and ongoing process named senescence, which induces changes at the molecular, cellular, and micro-anatomical levels in many body systems. The brain, being a highly complex organ, is particularly affected by this process, potentially impairing its numerous functions. The brain relies on chemical messengers known as neurotransmitters to function properly, with dopamine being one of the most crucial. This catecholamine is responsible for a broad range of critical roles in the central nervous system, including movement, learning, cognition, motivation, emotion, reward, hormonal release, memory consolidation, visual performance, sexual drive, modulation of circadian rhythms, and brain development. In the present review, we thoroughly examine the impact of senescence on the dopaminergic system, with a primary focus on the classic delimitations of the dopaminergic nuclei from A8 to A17. We provide in-depth information about their anatomy and function, particularly addressing how senescence affects each of these nuclei.


Assuntos
Envelhecimento , Dopamina , Neurônios Dopaminérgicos , Humanos , Animais , Envelhecimento/metabolismo , Envelhecimento/fisiologia , Dopamina/metabolismo , Neurônios Dopaminérgicos/metabolismo , Encéfalo/metabolismo
7.
PLoS Comput Biol ; 8(2): e1002383, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22346744

RESUMO

Dopamine release in the striatum has been implicated in various forms of reward dependent learning. Dopamine leads to production of cAMP and activation of protein kinase A (PKA), which are involved in striatal synaptic plasticity and learning. PKA and its protein targets are not diffusely located throughout the neuron, but are confined to various subcellular compartments by anchoring molecules such as A-Kinase Anchoring Proteins (AKAPs). Experiments have shown that blocking the interaction of PKA with AKAPs disrupts its subcellular location and prevents LTP in the hippocampus and striatum; however, these experiments have not revealed whether the critical function of anchoring is to locate PKA near the cAMP that activates it or near its targets, such as AMPA receptors located in the post-synaptic density. We have developed a large scale stochastic reaction-diffusion model of signaling pathways in a medium spiny projection neuron dendrite with spines, based on published biochemical measurements, to investigate this question and to evaluate whether dopamine signaling exhibits spatial specificity post-synaptically. The model was stimulated with dopamine pulses mimicking those recorded in response to reward. Simulations show that PKA colocalization with adenylate cyclase, either in the spine head or in the dendrite, leads to greater phosphorylation of DARPP-32 Thr34 and AMPA receptor GluA1 Ser845 than when PKA is anchored away from adenylate cyclase. Simulations further demonstrate that though cAMP exhibits a strong spatial gradient, diffusible DARPP-32 facilitates the spread of PKA activity, suggesting that additional inactivation mechanisms are required to produce spatial specificity of PKA activity.


Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Espinhas Dendríticas/enzimologia , Modelos Neurológicos , Plasticidade Neuronal/fisiologia , Animais , Biologia Computacional , Simulação por Computador , AMP Cíclico/metabolismo , Dopamina/metabolismo , Fosfoproteína 32 Regulada por cAMP e Dopamina/metabolismo , Humanos , Espaço Intracelular/metabolismo , Método de Monte Carlo , Reprodutibilidade dos Testes , Transdução de Sinais
8.
Front Syst Neurosci ; 17: 1242929, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37600831

RESUMO

The basal ganglia are a subcortical collection of interacting clusters of cell bodies, and are involved in reward, emotional, and motor circuits. Within all the brain processing necessary to carry out voluntary movement, the basal nuclei are fundamental, as they modulate the activity of the motor regions of the cortex. Despite being much studied, the motor circuit of the basal ganglia is still difficult to understand for many people at all, especially undergraduate and graduate students. This review article seeks to bring the functioning of this circuit with a simple and objective approach, exploring the functional anatomy, neurochemistry, neuronal pathways, related diseases, and interactions with other brain regions to coordinate voluntary movement.

9.
Poult Sci ; 101(2): 101607, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34936954

RESUMO

The aim of this study was to evaluate possible changes in the quality of chicken breast meat containing white stripes during freezing for 12 mo. Samples of Pectoralis major muscle from male Cobb 500 broilers containing white stripes in moderate and severe degrees were used, as well as samples from a control group (normal - absence of myopathies). Part of the samples (n = 60; n = 20 for each severity degree) were analyzed on the day of collection (beginning) and the rest (n = 240) was frozen (-20°C) for up to 12 mo. At the end of each proposed freezing period (3, 6, 9, and 12 mo), color, pH, water holding capacity, cooking loss, tenderness, lipid oxidation, chemical composition, cholesterol and collagen concentrations, myofibrillary fragmentation, and sarcomere length were analyzed. Microbiological analysis of samples was performed at the beginning and after 12 mo of freezing. Myopathy linked to freezing showed results of increased meat tenderness, with reduction of crude protein and mineral matter and increase of moisture, fat, and cholesterol, without affecting the meat's collagen percentages. However, these variations with the onset of myopathy do not compromise the consumption of broiled chicken breast meat, kept frozen for up to 12 mo.


Assuntos
Galinhas , Doenças Musculares , Animais , Congelamento , Masculino , Carne/análise , Doenças Musculares/etiologia , Doenças Musculares/veterinária , Músculos Peitorais
10.
J Chem Neuroanat ; 124: 102136, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35809809

RESUMO

Senescence is a natural and progressive physiological event that leads to a series of morphophysiological alterations in the organism. The brain is the most vulnerable organ to both structural and functional changes during this process. Dopamine is a key neurotransmitter for the proper functioning of the brain, directly involved in circuitries related with emotions, learning, motivation and reward. One of the main dopamine- producing nuclei is the substantia nigra pars compacta (SNpc), which establish connections with the striatum forming the so-called nigrostriatal pathway. S100B is a calcium binding protein mainly expressed by astrocytes, involved in both intracellular and extracellular processes, and whose expression is increased following injury in the nervous tissue, being a useful marker in altered status of central nervous system. The present study aimed to analyze the impact of senescence on the cells immunoreactive for tyrosine hydroxylase (TH) and S100B along the nigrostriatal pathway of the rat. Our results show an decreased expression of S100B+ cells in SNpc. In addition, there was a significant decrease in TH immunoreactivity in both projection fibers and TH+ cell bodies. In the striatum, a decrease in TH immunoreactivity was also observed, as well as an enlargement of the white matter bundles. Our findings point out that senescence is related to the anatomical and neurochemical changes observed throughout the nigrostriatal pathway.


Assuntos
Dopamina , Tirosina 3-Mono-Oxigenase , Animais , Astrócitos/metabolismo , Corpo Estriado/metabolismo , Dopamina/metabolismo , Ratos , Subunidade beta da Proteína Ligante de Cálcio S100/análise , Subunidade beta da Proteína Ligante de Cálcio S100/metabolismo , Subunidade beta da Proteína Ligante de Cálcio S100/farmacologia , Substância Negra/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismo
11.
Poult Sci ; 100(8): 101259, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34233253

RESUMO

Deep pectoral myopathy (DPM) considerably affects the meat quality of commercial poultry, thus representing a challenge to the poultry industry. In this study, we examined the breast meat quality of turkey breeder hens at disposal age affected by different degrees of DPM. Samples were collected from Nicholas turkeys at disposal age (385 d), at an average weight of 12.5 kg, which were reared and slaughtered in the south region of Brazil. The breast was first classified according to the degree of DPM and then samples of the Pectoralis major were collected from birds affected (DPM degrees 2 and 3; n = 20 of each) and nonaffected (normal, absence of lesions; n = 20) by the myopathy. After the affected Pectoralis minor muscle was discarded, the carcasses were released for human consumption by the Federal Inspection Service. The meat affected by the myopathy exhibited color changes (L*, a* and b*) (P < 0.05), especially in the inner surface. Higher (P < 0.05) water-holding capacity, pH, sarcomere length and fat concentration and lower (P < 0.05) shear force and moisture percentage were observed when compared to the normal samples. From this study, can be concluded that the severe condition of deep pectoral myopathy which affects the Pectoralis minor muscle, causes variations in the quality of Pectoralis major muscle of turkey on disposal age. As a raw material, this type of meat has a higher fat content and greater capacity for retaining intracellular water, important attributes to the manufacture of processed products. In this way, the processing is an economically viable alternative to the commercialization of breast meat from birds affected by myopathy.


Assuntos
Doenças Musculares , Perus , Animais , Brasil , Galinhas , Feminino , Carne/análise , Doenças Musculares/etiologia , Doenças Musculares/veterinária , Músculos Peitorais
12.
Am J Dermatopathol ; 31(8): 834-7, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19770630

RESUMO

Adult T-cell leukemia/lymphoma (ATL) is an aggressive type of leukemia/lymphoma associated with the human T-cell lymphotropic virus (HTLV-I). We describe an adult male patient clinically and pathologically diagnosed as mycosis fungoides and treated with chemotherapy after which complete involution of the lesions occurred. The disease relapsed with confluent dyshidrosis-like vesicles on the palmoplantar regions, followed by disseminated vesiculopapules and associated lymphocytosis. A serological test performed at this time revealed HTLV-I infection, and a diagnosis of chronic ATL was made. Monoclonal integration of HTLV-I was detected in peripheral blood mononuclear cells by inverse long polymerase chain reaction. A skin biopsy revealed spongiosis, Pautrier abscesses, and intraepidermal vesicles with atypical lymphocytes and an infiltration of small and atypical CD4 lymphocytes in the superficial dermis. Proliferative index (Ki-67) was 70%. This is the first reported vesicular cutaneous ATL with confirmation of HTLV-I proviral integration. The delay that occurred in diagnosing ATL was due to the fact that mycosis fungoides and ATL may present the same clinical, histopathological, and immunohistochemical features.


Assuntos
Eczema Disidrótico/patologia , Infecções por HTLV-I/patologia , Leucemia-Linfoma de Células T do Adulto/patologia , Micose Fungoide/patologia , Neoplasias Cutâneas/patologia , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Ciclofosfamida , Diabetes Mellitus , Diagnóstico Diferencial , Doxorrubicina , Eczema Disidrótico/virologia , Infecções por HTLV-I/complicações , Vírus Linfotrópico T Tipo 1 Humano , Humanos , Imuno-Histoquímica , Interferon-alfa/uso terapêutico , Leucemia-Linfoma de Células T do Adulto/tratamento farmacológico , Leucemia-Linfoma de Células T do Adulto/virologia , Masculino , Micose Fungoide/tratamento farmacológico , Reação em Cadeia da Polimerase , Prednisona , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/virologia , Vincristina , Zidovudina/uso terapêutico
14.
Rev Saude Publica ; 40(4): 734-6, 2006 Aug.
Artigo em Português | MEDLINE | ID: mdl-17063251

RESUMO

The objective of the study was to establish the prevalence rate of depression among the elderly population (those 60 and older) who frequent community centers. From February to July of 2001, a cross-sectional survey was conducted with elderly people from community centers in Taguatinga, Brasilia, FD (Federal District). The sample included 118 elderly people, distributed in five-year age brackets, who responded to a simplified version of the Yesavage Geriatric Depression Scale with 15 questions. Anova and the Tukey test were performed to analyze differences between the age groups with 95% confidence intervals. The sample was predominantly female (90%) with the majority reporting being in the age bracket of 60 to 64 years old (31%). Depression was reported by 36 respondents (31%) and severe depression was reported by 4% of those interviewed, all of whom were in the age bracket of 60 to 64 (representing 14% of this group). National programs should be developed in community centers focused on decreasing depression among the elderly population.


Assuntos
Centros Comunitários de Saúde , Depressão/epidemiologia , Avaliação Geriátrica , Idoso , Análise de Variância , Brasil/epidemiologia , Estudos Transversais , Depressão/diagnóstico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores Sexuais
15.
Elife ; 4: e09423, 2015 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-26417950

RESUMO

Learning to perform a complex motor task requires the optimization of specific behavioral features to cope with task constraints. We show that when mice learn a novel motor paradigm they differentially refine specific behavioral features. Animals trained to perform progressively faster sequences of lever presses to obtain reinforcement reduced variability in sequence frequency, but increased variability in an orthogonal feature (sequence duration). Trial-to-trial variability of the activity of motor cortex and striatal projection neurons was higher early in training and subsequently decreased with learning, without changes in average firing rate. As training progressed, variability in corticostriatal activity became progressively more correlated with behavioral variability, but specifically with variability in frequency. Corticostriatal plasticity was required for the reduction in frequency variability, but not for variability in sequence duration. These data suggest that during motor learning corticostriatal dynamics encode the refinement of specific behavioral features that change the probability of obtaining outcomes.


Assuntos
Comportamento Animal , Corpo Estriado/fisiologia , Aprendizagem , Córtex Motor/fisiologia , Potenciais de Ação , Animais , Locomoção , Camundongos , Plasticidade Neuronal
16.
Phys Rev E Stat Nonlin Soft Matter Phys ; 65(6 Pt 1): 060901, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12188696

RESUMO

Sensory arrays made of coupled excitable elements can improve both their input sensitivity and dynamic range due to collective nonlinear wave properties. This mechanism is studied in a neural network of electrically coupled (e.g., via gap junctions) elements subject to a Poisson signal process. The network response interpolates between a Weber-Fechner logarithmic law, and a Stevens power law depending on the relative refractory period of the cell. Therefore, these nonlinear transformations of the input level could be performed in the sensory periphery simply due to a basic property: the transfer function of excitable media.

17.
Methods Mol Biol ; 964: 61-75, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23296778

RESUMO

Dopamine binding to various dopamine receptors activates multiple intracellular signaling molecules, some of which interact with calcium activated signaling pathways. Many experiments measure agonist-stimulated elevations in signaling molecules using prolonged, diffuse application, whereas the response of neurons to transient and spatially localized stimuli is more important. Computational modeling is an approach for investigating the spatial extent, time course, and interaction of postsynaptic signaling molecules activated by dopamine and other transmembrane receptors. NeuroRD is a simulation algorithm which can simulate large numbers of pathways and molecules in multiple spines attached to a dendrite. We explain how to gather the information needed to develop computational models, to implement such models in NeuroRD, to perform simulations, and to analyze the simulated data from these models.


Assuntos
Dopamina/metabolismo , Espaço Intracelular/metabolismo , Modelos Biológicos , Transdução de Sinais , Neurônios/citologia , Software , Sinapses/metabolismo
18.
Am J Clin Pathol ; 140(3): 348-54, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23955453

RESUMO

OBJECTIVES: To evaluate the frequency of the different types of cutaneous lymphoma (CL) in 1 university hospital in Brazil and compare this frequency with those observed in other countries. METHODS: After review, 72 (84.7%) cases of primary cutaneous T-cell lymphoma (CTCL) and 13 (15.3%) cases of primary cutaneous B-cell lymphoma (CBCL) were included. RESULTS: Of the CTCLs, 40.3% were mycosis fungoides (MF); 26.4% were adult T-cell leukemias/lymphomas (ATLs); 23.6% were peripheral T-cell lymphomas, unspecified; and 8.3% were anaplastic large cell lymphomas. Of the MF cases, 17.2% progressed to transformed MF. Five-year survival for primary human T-cell lymphotropic virus type 1-negative CTCL, ATL, and CBCL was 64.0%, 42.1%, and 62.5%, respectively. MF and ATL were the most frequent primary CTCLs. CONCLUSIONS: The frequencies observed here are close to those observed in Peru but different from those of European countries. Unfortunately, the World Health Organization/European Organization of Research and Treatment of Cancer classification does not include primary cutaneous ATL.


Assuntos
Linfoma de Células B/patologia , Linfoma Cutâneo de Células T/patologia , Neoplasias Cutâneas/patologia , Pele/patologia , Adulto , Idoso , Brasil , Feminino , Humanos , Linfoma de Células B/metabolismo , Linfoma de Células B/mortalidade , Linfoma Cutâneo de Células T/metabolismo , Linfoma Cutâneo de Células T/mortalidade , Masculino , Pessoa de Meia-Idade , Pele/metabolismo , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/mortalidade , Taxa de Sobrevida
19.
PLoS One ; 5(7): e11725, 2010 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-20661441

RESUMO

Cyclic AMP (cAMP) and its main effector Protein Kinase A (PKA) are critical for several aspects of neuronal function including synaptic plasticity. Specificity of synaptic plasticity requires that cAMP activates PKA in a highly localized manner despite the speed with which cAMP diffuses. Two mechanisms have been proposed to produce localized elevations in cAMP, known as microdomains: impeded diffusion, and high phosphodiesterase (PDE) activity. This paper investigates the mechanism of localized cAMP signaling using a computational model of the biochemical network in the HEK293 cell, which is a subset of pathways involved in PKA-dependent synaptic plasticity. This biochemical network includes cAMP production, PKA activation, and cAMP degradation by PDE activity. The model is implemented in NeuroRD: novel, computationally efficient, stochastic reaction-diffusion software, and is constrained by intracellular cAMP dynamics that were determined experimentally by real-time imaging using an Epac-based FRET sensor (H30). The model reproduces the high concentration cAMP microdomain in the submembrane region, distinct from the lower concentration of cAMP in the cytosol. Simulations further demonstrate that generation of the cAMP microdomain requires a pool of PDE4D anchored in the cytosol and also requires PKA-mediated phosphorylation of PDE4D which increases its activity. The microdomain does not require impeded diffusion of cAMP, confirming that barriers are not required for microdomains. The simulations reported here further demonstrate the utility of the new stochastic reaction-diffusion algorithm for exploring signaling pathways in spatially complex structures such as neurons.


Assuntos
AMP Cíclico/metabolismo , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4/metabolismo , Linhagem Celular , Biologia Computacional , Simulação por Computador , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4/química , Transferência Ressonante de Energia de Fluorescência , Humanos , Modelos Teóricos , Software
20.
Photomed Laser Surg ; 28(2): 167-71, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20232997

RESUMO

OBJECTIVE: The aim of the present study was to analyze the effects of photobiomodulation using a 904-nm diode laser at two energy densities (6 J/cm(2) and 50 mJ/cm(2)) on L929 fibroblast cells. BACKGROUND: Low-power laser irradiation (LPLI) is a non-pharmacological resource that induces important in vitro photobiomodulation on cell cultures and tissues. METHODS: Irradiation was performed for three days at 24-h intervals. After each interval, the cells were stained with MitoTracker Orange and DioC6 dyes to assess the photobiomodulatory effects of irradiation on mitochondrial activity and changes in the endoplasmic reticulum. The MTT assay [3-(4.5-dimethylthiazol-2-yl)-2.5 diphenyltetrazolium bromide] was used to evaluate cell proliferation. RESULTS AND CONCLUSIONS: The fluorescence microscopy assessment of mitochondria and endoplasmic reticulum in cells irradiated with 6 J/cm(2) and 50 mJ/cm(2) demonstrated intense mitochondrial activity, which was confirmed by DioC6 staining. Reticular activity was observed stemming from increased protein synthesis. Photobiomodulation with 50 mJ/cm(2) was slightly higher than with 6 J/cm(2), as demonstrated by fluorescence microscopy results. Photobiomodulation was also time-dependent, with better results 72-h after irradiation.


Assuntos
Divisão Celular/efeitos da radiação , Lasers , Animais , Células Cultivadas , Retículo Endoplasmático/efeitos da radiação , Fibroblastos/efeitos da radiação , Camundongos , Microscopia de Fluorescência , Mitocôndrias/efeitos da radiação , Sais de Tetrazólio , Fatores de Tempo
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