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1.
J Neuroinflammation ; 21(1): 53, 2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38383441

RESUMO

BACKGROUND: Parkinson's disease (PD) is a common and costly progressive neurodegenerative disease of unclear etiology. A disease-modifying approach that can directly stop or slow its progression remains a major unmet need in the treatment of PD. A clinical pharmacology-based drug repositioning strategy is a useful approach for identifying new drugs for PD. METHODS: We analyzed claims data obtained from the National Health Insurance Service (NHIS), which covers a significant portion of the South Korean population, to investigate the association between antihistamines, a class of drugs commonly used to treat allergic symptoms by blocking H1 receptor, and PD in a real-world setting. Additionally, we validated this model using various animal models of PD such as the 6-hydroxydopmaine (6-OHDA), α-synuclein preformed fibrils (PFF) injection, and Caenorhabditis elegans (C. elegans) models. Finally, whole transcriptome data and Ingenuity Pathway Analysis (IPA) were used to elucidate drug mechanism pathways. RESULTS: We identified fexofenadine as the most promising candidate using National Health Insurance claims data in the real world. In several animal models, including the 6-OHDA, PFF injection, and C. elegans models, fexofenadine ameliorated PD-related pathologies. RNA-seq analysis and the subsequent experiments suggested that fexofenadine is effective in PD via inhibition of peripheral immune cell infiltration into the brain. CONCLUSION: Fexofenadine shows promise for the treatment of PD, identified through clinical data and validated in diverse animal models. This combined clinical and preclinical approach offers valuable insights for developing novel PD therapeutics.


Assuntos
Doenças Neurodegenerativas , Doença de Parkinson , Terfenadina/análogos & derivados , Animais , Doença de Parkinson/patologia , Caenorhabditis elegans/metabolismo , Doenças Neurodegenerativas/metabolismo , Oxidopamina , Modelos Animais de Doenças , alfa-Sinucleína/metabolismo , Neurônios Dopaminérgicos
2.
Pharmacol Res ; 209: 107432, 2024 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-39313081

RESUMO

Parkinson's disease (PD) is characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra (SN) and accumulation of intracellular α-synuclein (ɑ-syn) aggregates known as Lewy bodies and Lewy neurites. Levels of polyunsaturated fatty acids (PUFAs) have previously been shown to be reduced in the SN of PD patients. G protein-coupled receptor 40 (GPR40) serves as a receptor for PUFAs, playing a role in neurodevelopment and neurogenesis. Additionally, GPR40 has been implicated in several neuropathological conditions, such as apoptosis and inflammation, suggesting its potential as a therapeutic target in PD. In this study, we investigated the neuroprotective effects of the GPR40 agonist, TUG469 in PD models. Our results demonstrated that TUG469 reduces the neurotoxicity induced by 6-OHDA in SH-SY5Y cells. In 6-OHDA-induced PD model mice, TUG469 treatment improved motor impairment, preserved dopaminergic fibers and cell bodies in the striatum (ST) or SN, and attenuated 6-OHDA-induced microgliosis and astrogliosis in the brain. Furthermore, in a PD model involving the injection of mouse ɑ-syn fibrils into the brain (mPFFs-PD model), TUG469 treatment reduced the levels of pSer129 ɑ-syn, and decreased microgliosis and astrogliosis. Our investigation also revealed that TUG469 modulates inflammasome activation, apoptosis, and autophagy in the 6-OHDA-PD model, as evidenced by the results of RNA-seq and western blotting analyses. In summary, our findings highlight the neuroprotective effects of GPR40 agonists on dopaminergic neurons and their potential as therapeutic agents for PD. These results underscore the importance of targeting GPR40 in PD treatment, particularly in mitigating neuroinflammation and preserving neuronal integrity.

3.
Proc Natl Acad Sci U S A ; 115(7): 1629-1634, 2018 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-29386384

RESUMO

Mutations in DJ-1 (PARK7) are a known cause of early-onset autosomal recessive Parkinson's disease (PD). Accumulating evidence indicates that abnormalities of synaptic vesicle trafficking underlie the pathophysiological mechanism of PD. In the present study, we explored whether DJ-1 is involved in CNS synaptic function. DJ-1 deficiency impaired synaptic vesicle endocytosis and reavailability without inducing structural alterations in synapses. Familial mutants of DJ-1 (M26I, E64D, and L166P) were unable to rescue defective endocytosis of synaptic vesicles, whereas WT DJ-1 expression completely restored endocytic function in DJ-1 KO neurons. The defective synaptic endocytosis shown in DJ-1 KO neurons may be attributable to alterations in membrane cholesterol level. Thus, DJ-1 appears essential for synaptic vesicle endocytosis and reavailability, and impairment of this function by familial mutants of DJ-1 may be related to the pathogenesis of PD.


Assuntos
Endocitose/fisiologia , Terminações Nervosas/patologia , Proteína Desglicase DJ-1/fisiologia , Sinapses/patologia , Vesículas Sinápticas/patologia , Animais , Células Cultivadas , Camundongos , Camundongos Knockout , Mutação , Terminações Nervosas/metabolismo , Sinapses/metabolismo , Vesículas Sinápticas/metabolismo
4.
Cells ; 12(17)2023 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-37681864

RESUMO

Stroke is a major global health problem that causes significant mortality and long-term disability. Post-stroke neurological impairment is a complication that is often underestimated with the risk of persistent neurological deficits. Although traditional Chinese medicines have a long history of being used for stroke, their scientific efficacy remains unclear. Scutellaria baicalensis, an herbal component known for its anti-inflammatory and antioxidant properties, has traditionally been used to treat brain disorders. This study investigated the therapeutic effects of the Scutellaria baicalensis extraction (SB) during the acute stage of ischemic stroke using photothrombotic (PTB)-induced and transient middle cerebral artery occlusion (tMCAO) model mice. We found that SB mitigated ischemic brain injury, as evidenced by a significant reduction in the modified neurological severity score in the acute stage of PTB and both the acute and chronic stages of tMCAO. Furthermore, we elucidated the regulatory role of SB in the necroptosis and pyroptosis pathways during the acute stage of stroke, underscoring its protective effects. Behavioral assessments demonstrated the effectiveness of SB in ameliorating motor dysfunction and cognitive impairment compared to the group receiving the vehicle. Our findings highlight the potential of SB as a promising therapeutic candidate for stroke. SB was found to help modulate the programmed cell death pathways, promote neuroprotection, and facilitate functional recovery.


Assuntos
AVC Isquêmico , Acidente Vascular Cerebral , Animais , Camundongos , AVC Isquêmico/tratamento farmacológico , Scutellaria baicalensis , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/tratamento farmacológico , Apoptose , Piroptose
5.
Mol Brain ; 14(1): 122, 2021 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-34321069

RESUMO

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease, with aging being considered the greatest risk factor for developing PD. Caveolin-1 (Cav-1) is known to participate in the aging process. Recent evidence indicates that prion-like propagation of misfolded α-synuclein (α-syn) released from neurons to neighboring neurons plays an important role in PD progression. In the present study, we demonstrated that cav-1 expression in the brain increased with age, and considerably increased in the brain of A53T α-syn transgenic mice. Cav-1 overexpression facilitated the uptake of α-syn into neurons and formation of additional Lewy body-like inclusion bodies, phosphorylation of cav-1 at tyrosine 14 was found to be crucial for this process. This study demonstrates the relationship between age and α-syn spread and will facilitate our understanding of the molecular mechanism of the cell-to-cell transmission of α-syn.


Assuntos
Envelhecimento/metabolismo , Caveolina 1/metabolismo , Neurônios/metabolismo , alfa-Sinucleína/metabolismo , Animais , Encéfalo/patologia , Linhagem Celular Tumoral , Células Cultivadas , Endocitose , Humanos , Corpos de Inclusão/metabolismo , Corpos de Lewy/metabolismo , Masculino , Microdomínios da Membrana , Camundongos Endogâmicos C57BL , Modelos Biológicos , Fosforilação , Fosfotirosina/metabolismo , Proteólise , Ratos Sprague-Dawley
6.
J Vet Med Sci ; 72(2): 197-201, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19942812

RESUMO

Leptospirosis is a zoonotic disease of global importance, and has a worldwide distribution. The present study aimed to determine leptospiral seroprevalence in clinically healthy racing horses from all three racecourses in Korea. Serum samples from 1,226 racing horses were examined using a microscopic agglutination test to detect the presence of antibodies against 18 Leptospira serovars. Of the tested samples, 307 (25.0%) were found to be positive. The distribution of seroprevalence differed significantly by racecourse (P=0.004); the Jeju course had the highest incidence (31.1%), followed by the Seoul (25.2%) and Busan (19.5%) racecourses. Seasonal variation in seropositivity was also apparent (P=0.000), being lower in spring (13.0%) and winter (12.5%), and higher in summer (36.7%) and autumn (34.7%). No significant age- or gender-related difference in seroprevalence was noted in this study (P>0.05). Seroprevalence was higher (P=0.006) among ponies than among thoroughbreds. Sejroe was the most frequently detected serovar (n=236), followed by Bratislava (n=35), Ballum (n=16), Autumnalis (n=10), and Canicola (n=10). The majority of serum titers were relatively low; most values ranged from 1:100 (n=217) to 1:200 (n=69). These results suggest that the Sejroe serovar may be maintained in the racing horse population in Korea.


Assuntos
Doenças dos Cavalos/parasitologia , Leptospira/isolamento & purificação , Leptospirose/parasitologia , Zoonoses/parasitologia , Fatores Etários , Testes de Aglutinação/veterinária , Animais , Anticorpos Antiprotozoários/sangue , Distribuição de Qui-Quadrado , Feminino , Doenças dos Cavalos/epidemiologia , Cavalos , Coreia (Geográfico)/epidemiologia , Leptospirose/epidemiologia , Masculino , Estações do Ano , Estudos Soroepidemiológicos , Fatores Sexuais , Zoonoses/epidemiologia
7.
Mol Cell Biol ; 26(11): 4327-38, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16705182

RESUMO

Amyloid precursor protein (APP) has eight potential phosphorylation sites in its cytoplasmic domain. Recently, it has demonstrated that the constitutive phosphorylation of APP at T668 (APP695 isoform numbering) was observed specifically in the brain. Neuron-specific phosphorylation of APP at T668 is thought to be important for neuronal functions of APP, although its exact physiological significance remains to be clarified. In this study, we show that the phosphorylation of the APP intracellular domain (AICD) at T668 is essential for its binding to Fe65 and its nuclear translocation and affects the resultant neurotoxicity, possibly mediated through the induction of glycogen synthase kinase 3beta and tau phosphorylation by enhancing the formation of a ternary complex with Fe65 and CP2 transcription factor. Taken together, these results suggest that the phosphorylation of AICD at T668 contributes to the neuronal degeneration in Alzheimer's disease (AD) by regulating its translocation into the nucleus and then affects neurodegeneration; therefore, the specific inhibitor of T668 phosphorylation might be the target of AD therapy.


Assuntos
Precursor de Proteína beta-Amiloide/química , Precursor de Proteína beta-Amiloide/metabolismo , Núcleo Celular/metabolismo , Degeneração Neural/metabolismo , Degeneração Neural/patologia , Treonina/metabolismo , Transporte Ativo do Núcleo Celular , Doença de Alzheimer/patologia , Animais , Encéfalo/citologia , Encéfalo/patologia , Morte Celular , Células Cultivadas , Quinase 3 da Glicogênio Sintase/antagonistas & inibidores , Glicogênio Sintase Quinase 3 beta , Humanos , Camundongos , Camundongos Transgênicos , Mutação/genética , Fator de Crescimento Neural/farmacologia , Proteínas do Tecido Nervoso/metabolismo , Neurônios/citologia , Neurônios/efeitos dos fármacos , Proteínas Nucleares/metabolismo , Células PC12 , Fosforilação , Estrutura Terciária de Proteína , Transporte Proteico , Ratos , Proteínas tau/metabolismo
8.
J Vet Med Sci ; 66(4): 351-6, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15133263

RESUMO

The expression of three isoforms of nitric oxide synthase (NOS) were examined in the testis and epididymis of a thoroughbred horse. Immunohistochemical studies demonstrated the presence of eNOS immunostaining in some germ cells in the seminiferous tubules and in vascular endothelial cells in the interstitial tissues. Interstitial cells, most likely Leydig cells, were also intensely immunopositive for eNOS. The pattern of immunostaining for nNOS was similar to that for eNOS in the testis. Weak expression of iNOS was detected in the seminiferous tubules of the testis, but intense expression was found in interstitial cells. Inducible NOS was also strongly detected in stereocilia, sperm, epithelium and connective tissue of the epididymis of normal horses. These findings suggest that three isoforms of NOS are expressed in the testis and epididymis of horse and that they play important roles in the biology of interstitial cells that produce testosterone, as well as in spermatogenesis in the seminiferous tubules.


Assuntos
Cavalos/metabolismo , Óxido Nítrico Sintase/metabolismo , Testículo/metabolismo , Animais , Imuno-Histoquímica , Masculino , Óxido Nítrico Sintase Tipo I , Óxido Nítrico Sintase Tipo II , Óxido Nítrico Sintase Tipo III , Espermatozoides/metabolismo
9.
J Vet Sci ; 4(1): 21-8, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12819361

RESUMO

Lectins are glycoproteins of plant and animal origin that have the ability to bind specific carbohydrate residues of cell glycoconjugates, particularly in terminal positions. In this study, the binding of lectins, Dolichos biflorus agglutinin (DBA), soybean agglutinin (SBA), Bandeiraea simplicifolia BS-1 (isolectin B4), Triticum vulgaris (WGA), Arachis hypogaea (PNA), and Ulex europaeus (UEA-I), was studied in the reproductive systems of male thoroughbred horses.DBA was detected in the stereocilia of the caput and corpus epididymis, and in the vas deferens. It was weakly detected in connective tissue of the corpus epididymis. Strong SBA staining was seen in epithelial cells in the testis, stereocilia of the corpus and cauda epididymis, and in the vas deferens. There were intense positive reactions for isolectin B4 in interstitial cells in all tissue and serosa of the vas deferens. PNA staining was seen only in stereocilia in the caput and corpus epididymis, and in the vas deferens. Strong WGA staining was seen throughout the testis, except in Sertoli cells, stereocilia, and connective tissue. UEA-I was detected in secondary spermatids, stereocilia, and epithelial cells of the cauda epididymis. These results show that degenerating cells in the testis, epididymal tubules, and vas deferens have differential affinities for lectins, and suggest that lectins play a role in the reproductive system of the horse. The heterogeneity of the lectin staining pattern in the reproductive tubules of adult horses suggests that the carbohydrate composition of each cell type is region specific.


Assuntos
Epididimo/metabolismo , Cavalos/metabolismo , Lectinas/metabolismo , Testículo/metabolismo , Ducto Deferente/metabolismo , Animais , Epididimo/citologia , Imuno-Histoquímica/veterinária , Masculino , Testículo/citologia , Ducto Deferente/citologia
10.
Arch Pharm Res ; 37(5): 671-8, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-23897163

RESUMO

In type 2 diabetes mellitus (T2DM) patients, the gradual loss of pancreatic ß-cell function is a characteristic feature of disease progression that is associated with sustained hyperglycemia. Recently, G protein-coupled receptor 119 (GPR119) has been identified as a promising anti-diabetic therapeutic target. It is predominantly expressed in pancreatic ß-cells, directly promotes glucose stimulated insulin secretion and indirectly increases glucagon-like peptide 1 (GLP-1) levels reducing appetite and food intake. Activation of GPR119 leads to insulin release in ß-cells by increasing intracellular cAMP. Here, we identified a novel structural class of small-molecule GPR119 agonists, HD0471042, consisting of substituted a 3-isopropyl-1,2,4-oxadiazol-piperidine derivative with promising potential for the treatment of T2DM. The GPR119 agonist, HD0471042 increased intracellular cAMP levels in stably human GPR119 expressing CHO cell lines and HIT-T15 cell lines, hamster ß-cell line expressing endogenously GPR119. HD0471042, significantly elevated insulin release in INS-1 cells of rat pancreatic ß-cell line. In in vivo experiments, a single dose of HD0471042 improved glucose tolerance. Insulin and GLP-1 level were increased in a dose-dependent manner. Treatment with HD0471042 for 6 weeks in diet induced obesity mice and for 4 weeks in ob/ob and db/db mice improved glycemic control and also reduced weight gain in a dose-dependent manner. These data demonstrate that the novel GPR119 agonist, HD0471042, not only effectively controlled glucose levels, but also had an anti-obesity effect, a feature observed with GLP-1. We therefore suggest that HD0471042 represents a new type of anti-diabetes agent with anti-obesity potential for the effective treatment of type 2 diabetes.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/farmacologia , Células Secretoras de Insulina/efeitos dos fármacos , Oxidiazóis/farmacologia , Piperidinas/farmacologia , Receptores Acoplados a Proteínas G/agonistas , Animais , Fármacos Antiobesidade/farmacologia , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Células CHO , Cricetulus , AMP Cíclico/metabolismo , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/fisiopatologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Desenho de Fármacos , Peptídeo 1 Semelhante ao Glucagon/sangue , Humanos , Hipoglicemiantes/química , Insulina/sangue , Células Secretoras de Insulina/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Obesidade/sangue , Obesidade/tratamento farmacológico , Obesidade/fisiopatologia , Oxidiazóis/química , Piperidinas/química , Ratos , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Relação Estrutura-Atividade , Fatores de Tempo , Transfecção , Aumento de Peso/efeitos dos fármacos
11.
Biomol Ther (Seoul) ; 22(5): 400-5, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25414769

RESUMO

G-protein coupled receptor 119 (GPR119) has emerged as a novel target for the treatment of type 2 diabetes mellitus. GPR119 is involved in glucose-stimulated insulin secretion (GSIS) from the pancreatic ß-cells and intestinal cells. In this study, we identified a novel small-molecule GPR119 agonist, HD047703, which raises intracellular cAMP concentrations in pancreatic ß-cells and can be expected to potentiate glucose-stimulated insulin secretion from human GPR119 receptor stably expressing cells (CHO cells). We evaluated the acute efficacy of HD047703 by the oral glucose tolerance test (OGTT) in normal C57BL/6J mice. Then, chronic administrations of HD047703 were performed to determine its efficacy in various diabetic rodent models. Single administration of HD047703 caused improved glycemic control during OGTT in a dose-dependent manner in normal mice, and the plasma GLP-1 level was also increased. With respect to chronic efficacy, we observed a decline in blood glucose levels in db/db, ob/ob and DIO mice. These results suggest that HD047703 may be a potentially promising anti-diabetic agent.

12.
PLoS One ; 9(2): e88924, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24586443

RESUMO

Our previous study presented evidence that the inflammation-related S100A9 gene is significantly upregulated in the brains of Alzheimer's disease (AD) animal models and human AD patients. In addition, experiments have shown that knockdown of S100A9 expression improves cognition function in AD model mice (Tg2576), and these animals exhibit reduced amyloid plaque burden. In this study, we established a new transgenic animal model of AD by crossbreeding the Tg2576 mouse with the S100A9 knockout (KO) mouse. We observed that S100A9KO/Tg2576 (KO/Tg) mice displayed an increased spatial reference memory in the Morris water maze task and Y-maze task as well as decreased amyloid beta peptide (Aß) neuropathology because of reduced levels of Aß, C-terminal fragments of amyloid precursor protein (APP-CT) and phosphorylated tau and increased expression of anti-inflammatory IL-10 and also decreased expression of inflammatory IL-6 and tumor neurosis factor (TNF)-α when compared with age-matched S100A9WT/Tg2576 (WT/Tg) mice. Overall, these results suggest that S100A9 is responsible for the neurodegeneration and cognitive deficits in Tg2576 mice. The mechanism of S100A9 is able to coincide with the inflammatory process. These findings indicate that knockout of S100A9 is a potential target for the pharmacological therapy of AD.


Assuntos
Calgranulina B/genética , Transtornos Cognitivos/genética , Transtornos da Memória/genética , Camundongos Knockout/genética , Doenças Neurodegenerativas/genética , Peptídeos beta-Amiloides/genética , Peptídeos beta-Amiloides/metabolismo , Animais , Calgranulina B/metabolismo , Transtornos Cognitivos/metabolismo , Modelos Animais de Doenças , Feminino , Interleucina-10/genética , Interleucina-10/metabolismo , Interleucina-6/genética , Interleucina-6/metabolismo , Masculino , Transtornos da Memória/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout/metabolismo , Camundongos Transgênicos/genética , Camundongos Transgênicos/metabolismo , Doenças Neurodegenerativas/metabolismo , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo
13.
J Diabetes Res ; 2013: 269569, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24386644

RESUMO

G-protein coupled receptor 119 (GPR119) has emerged as a promising new target for the treatment of type 2 diabetes mellitus. The expression of GPR119 on the pancreatic B cells and intestinal L cells provides a unique opportunity for a single drug to promote insulin and GLP-1 secretion. In this study, we identified a novel small molecule GPR119 agonist, HD0471953, from our large library of synthetic compounds based on its ability to anti-hyperglycemic effects on T2DM murine models. We have tested the acute efficacy of HD0471953 by the oral glucose tolerance test (OGTT) with normal C57BL/6J mice. Then, chronic administrations of HD0471953 were performed to evaluate the efficacy on various diabetic rodent models. Single administration of HD0471953 showed improved glycemic control with a dose-dependent manner in OGTT with normal mice, and the insulin and GLP-1 were also increased. To identify chronic efficacy, we have observed a decline of blood glucose and fasting insulin in a dose-dependent manner of 10, 20, and 50 mpk in db/db mice. The results suggest that HD0471953 may be a potentially promising anti-hyperglycemic agent for the treatment of patients with type 2 diabetes mellitus.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Receptores Acoplados a Proteínas G/agonistas , Animais , Glicemia/metabolismo , Células Cultivadas , AMP Cíclico/metabolismo , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 2/patologia , Avaliação Pré-Clínica de Medicamentos , Teste de Tolerância a Glucose , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Resultado do Tratamento
14.
Phys Med Biol ; 57(11): 3643-59, 2012 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-22596083

RESUMO

Magnetic resonance electrical impedance tomography (MREIT) is a non-invasive method to visualize cross-sectional electrical conductivity and/or current density by measuring a magnetic flux density signal when an electrical current is injected into a subject. In the MREIT system, it is crucial to reduce the scan duration while maintaining spatial resolution and contrast for practical in vivo implementation. The purpose of the study is to optimize the measured magnetic flux density using an interleaved multiple-echo pulse sequence (injected current nonlinear encoding) that acquires each spatial position multiple times, although these pixels vary between echoes in their signal-to-noise ratio due to (a) T*2 decay and (b) the current density passing through the pixel. Using the acquired multiple measured magnetic flux densities, the noise level for the measured magnetic flux density B(z) at each pixel is estimated using the relationship between the intensity of the magnitude and the width of the injected current. We determine an optimal combination of the multiply acquired magnetic flux densities, which optimally reduces the random noise artifacts. We develop a new denoising technique and apply it to a recovered conductivity distribution with a known noise level of the recovered magnetic flux density, which is designed to provide a stable internal conductivity distribution, while sustaining resolution. The proposed method uses three key steps: the first step is optimizing the magnetic flux density by using the multiple-echo magnetic flux densities at each pixel, the second step is estimating the noise level of this optimized magnetic flux density and the third step is applying a denoising technique using the pixel-specific estimated noise level. Numerical simulation experiments using a three-dimensional cylindrical phantom model validated the proposed method. Multiple-echo B(z) data were generated, including in short T*2 or low spin-density regions, as a function of T*2 and the temporal extent of the injected current. In the simulation experiment, comparing between an equally averaged and the optimized B(z) methods, relative L2-mode errors were 0.053 and 0.024, respectively. In an actual imaging experiment of an agarose gel filled with objects of various conductivities and shapes, we acquired six echoes per repetition time. The optimal weighting factors minimized the effects of noise in B(z), and provided reconstructed conductivity maps that suppressed noise artifacts that normally accumulate in the low signal-to-noise-ratio defect regions.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Razão Sinal-Ruído , Impedância Elétrica , Humanos , Imagens de Fantasmas , Fatores de Tempo
15.
PLoS One ; 5(1): e8840, 2010 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-20098622

RESUMO

Inflammation, insoluble protein deposition and neuronal cell loss are important features in the Alzheimer's disease (AD) brain. To investigate the regulatory genes responsible for the neuropathology in AD, we performed microarray analysis with APP(V717I)-CT100 transgenic mice, an animal model of AD, and isolated the S100a9 gene, which encodes an inflammation-associated calcium binding protein. In another AD animal model, Tg2576 mouse brain, and in human AD brain, induction of S100a9 was confirmed. The endogenous expression of S100a9 was induced by treatment with Abeta or CT peptides in a microglia cell line, BV2 cells. In these cells, silencing study of S100a9 showed that the induction of S100a9 increased the intracellular calcium level and up-regulated the inflammatory cytokines (IL-1beta and TNFalpha) and iNOS. S100a9 lentiviral short hairpin RNA (sh-S100a9) was injected into the hippocampus region of the brains of 13-month-old Tg2576 mice. At two months after injection, we found that knockdown of S100a9 expression had improved the cognition decline of Tg2576 mice in the water maze task, and had reduced amyloid plaque burden. These results suggest that S100a9 induced by Abeta or CT contributes to cause inflammation, which then affects the neuropathology including amyloid plaques burden and impairs cognitive function. Thus, the inhibition of S100a9 is a possible target for AD therapy.


Assuntos
Doença de Alzheimer/patologia , Doença de Alzheimer/psicologia , Calgranulina B/fisiologia , Modelos Animais de Doenças , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/genética , Animais , Sequência de Bases , Encéfalo/metabolismo , Calgranulina B/genética , Linhagem Celular Transformada , Citocinas/fisiologia , Primers do DNA , Técnicas de Silenciamento de Genes , Humanos , Imuno-Histoquímica , Mediadores da Inflamação/fisiologia , Camundongos , Camundongos Transgênicos , Reação em Cadeia da Polimerase Via Transcriptase Reversa
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