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1.
Med Eng Phys ; 108: 103876, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36195370

RESUMO

Wearable human activity recognition systems (HAR) using inertial measurement units (IMU) play a key role in the development of smart rehabilitation systems. Training of a HAR system with patient data is costly, time-consuming, and difficult for the patients. This study proposes a new scheme for the optimal design of HARs with minimal involvement of the patients. It uses healthy subject data for optimal design for a set of activities used in the rehabilitation of PD1 patients. It maintains its performance for individual PD subjects using a single session data collection and an adaptation procedure. In the optimal design, several classifiers (i.e. NM, k-NN, MLP with RBF as a hidden layer, and multistage RBF SVM) were investigated. Features were signal-based in the time, frequency, and time-frequency domains. Double-stage feature extraction by PCA and fisher technique was used. The optimal design reached a recall of 95% on healthy subjects using only two sensors on the left thigh and forearm. Implementing the adaptation procedure on two PD subjects, the performance was maintained above 80%. Post analysis on the performance of the adapted HAR showed a slight drop in precision (above 87% to above 81%) for activities that was performed in sitting condition.


Assuntos
Telerreabilitação , Dispositivos Eletrônicos Vestíveis , Algoritmos , Atividades Humanas , Humanos
2.
J Ophthalmic Vis Res ; 15(4): 470-480, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33133437

RESUMO

PURPOSE: 7-ketocholesterol (7kCh), a natural byproduct of oxidation in lipoprotein deposits is implicated in the pathogenesis of diabetic retinopathy and age-related macular degeneration (AMD). This study was performed to investigate whether several clinical drugs can inhibit 7kCh-induced caspase activation and mitigate its apoptotic effects on retinal cells in vitro. METHODS: Two populations of retinal cells, human retinal pigment epithelial cells (ARPE-19) and rat neuroretinal cells (R28) were exposed to 7kCh in the presence of the following inhibitors: Z-VAD-FMK (pan-caspase inhibitor), simvastatin, memantine, epicatechin, and Z-IETD-FMK (caspase-8 inhibitor) or Z-ATAD-FMK (caspase-12 inhibitor). Caspase-3/7, -8, and -12 activity levels were measured by fluorochrome caspase assays to quantify cell death. IncuCyte live-cell microscopic images were obtained to quantify cell counts. RESULTS: Exposure to 7kCh for 24 hours significantly increased caspase activities for both ARPE-19 and R28 cells (P < 0.05). In ARPE cells, pretreatment with various drugs had significantly lower caspase-3/7, -8, and -12 activities, reported in % change in mean signal intensity (msi): Z-VAD-FMK (48% decrease, P < 0.01), memantine (decreased 47.8% at 1 µM, P = 0.0039 and 81.9% at 1 mM, P < 0.001), simvastatin (decreased 85.3% at 0.01 µM, P < 0.001 and 84.8% at 0.05 µM, P < 0.001) or epicatechin (83.6% decrease, P < 0.05), Z-IETD-FMK (68.1% decrease, P < 0.01), and Z-ATAD-FMK (47.7% decrease, P = 0.0017). In contrast, R28 cells exposed to 7kCh continued to have elevated caspase-3/7, -8, and -12 activities (between 25.7% decrease and 17.5% increase in msi, P > 0.05) regardless of the pretreatment. CONCLUSION: Several current drugs protect ARPE-19 cells but not R28 cells from 7kCh-induced apoptosis, suggesting that a multiple-drug approach is needed to protect both cells types in various retinal diseases.

3.
Int J Cosmet Sci ; 42(5): 444-451, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32583541

RESUMO

BACKGROUND: The loss of structural elastin due to intrinsic and extrinsic ageing results in the skin's inability to stretch and recoil (decrease in elasticity) and manifests as loss of skin firmness and sagging. While other extracellular matrix (ECM) components such as collagen and hyaluronic acid are continually synthesized and assembled through life, elastic fibres are not. Elastic fibre assembly and functionality require fibre cross-linking, induced by the lysyl oxidase-like (LOXL) enzymes, which sharply decrease during ageing. OBJECTIVE: To evaluate the enhanced elastogenic effect of a blackberry-dill extract combination, which was hypothesized to induce elastin fibre component synthesis, fibre cross-linking and reduce elastin fibre degradation. METHODS: The blackberry and the dill extracts were tested separately and in combination to confirm single ingredient bioactivity and synergistic benefits. Human skin explants, dermal fibroblasts, elastase assays, ELISAs, quantitative real-time PCRs and spectrofluorometer measurements were used. Moreover, a double-blinded, placebo-controlled clinical study was carried out to assess skin elasticity using Cutometer and histologically from biopsies. RESULTS: The blackberry extract induced elastin gene expression, elastin promoter activity and inhibited elastic fibre degradation by matrix metalloproteinases (MMPs) 9 and 12. The dill extract induced elastin, collagen and LOXL1 gene expression, resulting in enhanced fibre cross-linking in human skin explants. Clinically, the blackberry and dill combination treatment displayed synergistic pro-elasticity activity as compared to each ingredient alone and placebo. CONCLUSION: Taken together, these results demonstrated the two multimodal plant-based extracts complemented each other in terms of bioactivity and resulted in a synergistic elastogenesis induction.


CONTEXTE: la perte de l'élastine structurelle causée par un vieillissement intrinsèque et extrinsèque provoque l'incapacité de la peau à s'étirer et à rebondir (diminution de l'élasticité) et se manifeste comme une perte de fermeté et un relâchement de la peau. Alors que d'autres composants de la matrice extracellulaire (MEC), tels que le collagène et l'acide hyaluronique sont continuellement synthétisés et assemblés tout au long de la vie, les fibres élastiques ne le sont pas. L'assemblage et la fonctionnalité des fibres élastiques nécessitent une réticulation des fibres, causée par les enzymes de type lysyle oxydase (LOXL), qui diminuent fortement au cours du vieillissement. OBJECTIF: évaluer l'effet élastogène amélioré d'une combinaison d'extrait de mûre et d'aneth, qui était supposée induire la synthèse des composants des fibres d'élastine, la réticulation des fibres et réduire la dégradation des fibres d'élastine. MÉTHODES: les extraits de mûre et d'aneth ont été testés séparément et ensemble pour confirmer la bioactivité d'un seul ingrédient et les avantages synergiques. Des explants de peau humaine, des fibroblastes cutanés, des dosages d'élastase, des ELISA, des analyses PCR quantitatives en temps réel et des mesures de spectrofluorimètre ont été utilisés. De plus, une étude clinique en double aveugle, contrôlée par placebo, a été réalisée pour évaluer l'élasticité de la peau à l'aide du cutomètre et histologiquement à partir de biopsies. RÉSULTATS: l'extrait de mûre a induit l'expression génique de l'élastine, l'activité de promoteur de l'élastine et a inhibé la dégradation des fibres élastiques par des métalloprotéinases matricielles (MPM) 9 et 12.L'extrait d'aneth a causé l'expression génique de l'élastine, du collagène et du gène LOXL1, entraînant une amélioration de la réticulation des fibres dans les explants de peau humaine. Cliniquement, le traitement par une combinaison de mûre et d'aneth a montré une activité de pro-élasticité synergique par rapport à chaque ingrédient seul et au placebo. CONCLUSION: ensemble, ces résultats ont démontré que les deux extraits de plantes multimodales se complètent en termes de bioactivité et ont entraîné une induction synergique de l'élastogenèse.


Assuntos
Anethum graveolens/química , Elasticidade , Extratos Vegetais/farmacologia , Rubus/química , Pele/efeitos dos fármacos , Animais , Método Duplo-Cego , Sinergismo Farmacológico , Elastina/metabolismo , Matriz Extracelular/metabolismo , Humanos , Ratos , Pele/metabolismo , Espectrometria de Fluorescência
4.
Eur J Neurosci ; 43(9): 1190-202, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26833814

RESUMO

Brain reward circuits are implicated in stress-related psychiatric disorders. Exercise reduces the incidence of stress-related disorders, but the contribution of exercise reward to stress resistance is unknown. Exercise-induced stress resistance is independent of exercise controllability; both voluntary running (VR) and forced running (FR) protect rats against the anxiety-like and depression-like behavioural consequences of stress. Voluntary exercise is a natural reward, but whether rats find FR rewarding is unknown. Moreover, the contribution of dopamine (DA) and striatal reward circuits to exercise reward is not well characterized. Adult, male rats were assigned to locked wheels, VR, or FR groups. FR rats were forced to run in a pattern resembling the natural wheel running behavior of rats. Both VR and FR increased the reward-related plasticity marker ΔFosB in the dorsal striatum and nucleus accumbens, and increased the activity of DA neurons in the lateral ventral tegmental area, as revealed by immunohistochemistry for tyrosine hydroxylase and pCREB. Both VR and FR rats developed conditioned place preference (CPP) to the side of a CPP chamber paired with exercise. Re-exposure to the exercise-paired side of the CPP chamber elicited conditioned increases in cfos mRNA in direct-pathway (dynorphin-positive) neurons in the dorsal striatum and nucleus accumbens in both VR and FR rats, and in tyrosine hydroxylase-positive neurons in the lateral ventral tegmental area of VR rats only. The results suggest that the rewarding effects of exercise are independent of exercise controllability and provide insight into the DA and striatal circuitries involved in exercise reward and exercise-induced stress resistance.


Assuntos
Condicionamento Físico Animal , Recompensa , Estresse Psicológico/fisiopatologia , Animais , Corpo Estriado/citologia , Corpo Estriado/metabolismo , Corpo Estriado/fisiologia , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Neurônios Dopaminérgicos/metabolismo , Neurônios Dopaminérgicos/fisiologia , Masculino , Plasticidade Neuronal , Núcleo Accumbens/citologia , Núcleo Accumbens/metabolismo , Núcleo Accumbens/fisiologia , Proteínas Proto-Oncogênicas c-fos/genética , Proteínas Proto-Oncogênicas c-fos/metabolismo , Ratos , Ratos Endogâmicos F344 , Corrida , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismo
5.
PLoS One ; 10(11): e0141898, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26555633

RESUMO

Accumulating evidence from both the human and animal literature indicates that exercise reduces the negative consequences of stress. The neurobiological etiology for this stress protection, however, is not completely understood. Our lab reported that voluntary wheel running protects rats from expressing depression-like instrumental learning deficits on the shuttle box escape task after exposure to unpredictable and inescapable tail shocks (uncontrollable stress). Impaired escape behavior is a result of stress-sensitized serotonin (5-HT) neuron activity in the dorsal raphe (DRN) and subsequent excessive release of 5-HT into the dorsal striatum following exposure to a comparatively mild stressor. However, the possible mechanisms by which exercise prevents stress-induced escape deficits are not well characterized. The purpose of this experiment was to test the hypothesis that exercise blunts the stress-evoked release of 5-HT in the dorsal striatum. Changes to dopamine (DA) levels were also examined, since striatal DA signaling is critical for instrumental learning and can be influenced by changes to 5-HT activity. Adult male F344 rats, housed with or without running wheels for 6 weeks, were either exposed to tail shock or remained undisturbed in laboratory cages. Twenty-four hours later, microdialysis was performed in the medial (DMS) and lateral (DLS) dorsal striatum to collect extracellular 5-HT and DA before, during, and following 2 mild foot shocks. We report wheel running prevents foot shock-induced elevation of extracellular 5-HT and potentiates DA concentrations in both the DMS and DLS approximately 24 h following exposure to uncontrollable stress. These data may provide a possible mechanism by which exercise prevents depression-like instrumental learning deficits following exposure to acute stress.


Assuntos
Corpo Estriado/metabolismo , Dopamina/metabolismo , Condicionamento Físico Animal/fisiologia , Corrida/fisiologia , Serotonina/metabolismo , Estresse Psicológico/metabolismo , Animais , Eletrochoque , Desamparo Aprendido , Masculino , Microdiálise , Atividade Motora/fisiologia , Neurônios/metabolismo , Ratos , Ratos Endogâmicos F344
6.
Behav Brain Res ; 272: 252-63, 2014 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-25017571

RESUMO

Emerging evidence indicates that adenosine is a major regulator of striatum activity, in part, through the antagonistic modulation of dopaminergic function. Exercise can influence adenosine and dopamine activity, which may subsequently promote plasticity in striatum adenosine and dopamine systems. Such changes could alter activity of medium spiny neurons and impact striatum function. The purpose of this study was twofold. The first was to characterize the effect of long-term wheel running on adenosine 1 (A1R), adenosine 2A (A2AR), dopamine 1 (D1R), and dopamine 2 (D2R) receptor mRNA expression in adult rat dorsal and ventral striatum structures using in situ hybridization. The second was to determine if changes to adenosine and dopamine receptor mRNA from running are associated with altered cfos mRNA induction in dynorphin- (direct pathway) and enkephalin- (indirect pathway) expressing neurons of the dorsal striatum following stress exposure. We report that chronic running, as well as acute uncontrollable stress, reduced A1R and A2AR mRNA levels in the dorsal and ventral striatum. Running also modestly elevated D2R mRNA levels in striatum regions. Finally, stress-induced cfos was potentiated in dynorphin and attenuated in enkephalin expressing neurons of running rats. These data suggest striatum adenosine and dopamine systems are targets for neuroplasticity from exercise, which may contribute to changes in direct and indirect pathway activity. These findings may have implications for striatum mediated motor and cognitive processes, as well as exercise facilitated stress-resistance.


Assuntos
Corpo Estriado/fisiopatologia , Atividade Motora/fisiologia , Proteínas Proto-Oncogênicas c-fos/metabolismo , Corrida/fisiologia , Estresse Psicológico/fisiopatologia , Animais , Corticosterona/sangue , Dinorfinas/metabolismo , Eletrochoque , Encefalinas/metabolismo , Expressão Gênica/fisiologia , Masculino , Atividade Motora/efeitos dos fármacos , Neurônios/fisiologia , RNA Mensageiro/metabolismo , Distribuição Aleatória , Ratos Endogâmicos F344 , Receptor A1 de Adenosina/metabolismo , Receptor A2A de Adenosina/metabolismo , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/metabolismo , Estresse Psicológico/terapia
7.
Genes Immun ; 15(7): 457-65, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25008863

RESUMO

Single-nucleotide polymorphisms close to IL22RA2, coding for the soluble interleukin (IL)-22-binding protein (IL-22BP), are strongly and reproducibly associated with multiple sclerosis (MS), but there is little data on how this molecule may affect neuroinflammation. Here, we have studied the mouse ortholog in C57BL/6 wild-type and Il22ra2-deficient mice in the context of experimental autoimmune encephalomyelitis (myelin oligodendrocyte glycoprotein-EAE). In wild-type mice, we demonstrated changes in the levels of transcripts for IL-22, the signaling IL-22 receptor and IL-22BP in lymphoid tissues at the time of T-cell priming and in the inflamed central nervous system (CNS). Because IL-22BP is known to antagonize IL-22 signaling, a primarily pro-inflammatory cytokine, we hypothesized that the Il22ra2-deficient mice would have more severe EAE. Paradoxically, the knockout mice displayed a less severe disease course, less demyelination and less infiltration of immune cells in the CNS. The most straightforward interpretation of our findings is that lack of IL-22BP leads to a higher availability of IL-22, which in the case of CNS inflammation, surprisingly acts in a protective fashion. Thus, deletion of the ortholog of the MS risk gene Il22ra2 in mice has beneficial effects on EAE, which may be considered in new therapeutic strategies for treating neuroinflammation.


Assuntos
Encefalomielite Autoimune Experimental/genética , Esclerose Múltipla/genética , Receptores de Interleucina/genética , Animais , Sistema Nervoso Central/metabolismo , Sistema Nervoso Central/patologia , Encefalomielite Autoimune Experimental/metabolismo , Encefalomielite Autoimune Experimental/patologia , Tecido Linfoide/imunologia , Tecido Linfoide/metabolismo , Camundongos , Bainha de Mielina/metabolismo , Bainha de Mielina/patologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Interleucina/metabolismo
8.
Int J Tuberc Lung Dis ; 15(2): 240-5, i, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21219688

RESUMO

OBJECTIVE: To evaluate patients with mediastinal tuberculosis (MT), their demographic profiles, symptoms, radiological features and the role of mediastinoscopy. METHODS: This retrospective study conducted at Bradford Teaching Hospitals, Bradford, United Kingdom, looked at the case notes of 160 (13%) patients with MT out of a cohort of 1252 notifications of tuberculosis (TB) cases from 1995 to 2004, analysing the demographic data, diagnostic findings, computed tomography (CT) scans and outcomes. Interventions included bronchoscopy, lymph node biopsy and mediastinoscopy. RESULTS: Patient age ranged from 1 to 75 years; the majority were females and from minority ethnic groups. Contact history was positive in 76% of cases. Cough was the most common symptom (50%); however, asymptomatic patients were also common (45%). Heaf test was positive in 99%. Right paratracheal lymphadenopathy was common on chest X-ray and chest CT scan. Mediastinoscopy was performed in only 37 patients with definitive diagnosis. CONCLUSION: MT should be suspected in adult asymptomatic immigrants presenting with mediastinal adenopathy and a strongly positive Heaf test. Trial of anti-tuberculosis treatment should be initiated and response should guide further management. Mediastinoscopy is required in only a minority of patients.


Assuntos
Doenças do Mediastino/diagnóstico , Mediastinoscopia , Tuberculose dos Linfonodos/diagnóstico , Adolescente , Adulto , Idoso , Antituberculosos/uso terapêutico , Biópsia , Criança , Pré-Escolar , Busca de Comunicante , Quimioterapia Combinada , Emigração e Imigração , Inglaterra/epidemiologia , Feminino , Hospitais de Ensino , Humanos , Lactente , Masculino , Doenças do Mediastino/tratamento farmacológico , Doenças do Mediastino/etnologia , Doenças do Mediastino/microbiologia , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Teste Tuberculínico , Tuberculose dos Linfonodos/tratamento farmacológico , Tuberculose dos Linfonodos/etnologia , Tuberculose dos Linfonodos/microbiologia , Adulto Jovem
9.
J Invest Dermatol ; 113(6): 1099-105, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10594758

RESUMO

p63, a recently identified member of the p53 gene family, encodes multiple products with transactivating, death-inducing, and dominant-negative activities. We show that in normal human epidermis, in hair follicles, and in stratified epidermal cultures, p63 protein is principally restricted to cells with high proliferative potential and is absent from the cells that are undergoing terminal differentiation. In normal human epidermis and in hair follicles, basal cells with abundant p63 are interspersed with cells with little or no p63. Whenever p63 mRNA is present, it encodes mainly truncated, potentially dominant-negative isotypes. In squamous cell carcinomas, the number of cells containing p63 and their distribution depends on the degree of anaplasia. In highly differentiated tumors, p63 is confined to a ring of basal-like cells surrounding, but at a distance from, centers of terminal differentiation. In less differentiated tumors, most cells contain p63 and their distribution is chaotic with respect to centers of terminal differentiation. p63 appears to be a valuable diagnostic marker for anaplastic keratinocytes.


Assuntos
Queratinócitos/fisiologia , Proteínas de Membrana , Fosfoproteínas/fisiologia , Neoplasias Cutâneas/patologia , Transativadores , Carcinoma de Células Escamosas/química , Divisão Celular , Células Cultivadas , Proteínas de Ligação a DNA , Epiderme/química , Genes Supressores de Tumor , Folículo Piloso/química , Humanos , Antígeno Ki-67/análise , Fosfoproteínas/análise , Fosfoproteínas/genética , RNA Mensageiro/análise , Fatores de Transcrição , Proteínas Supressoras de Tumor
10.
Eur J Biochem ; 236(1): 214-21, 1996 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-8617267

RESUMO

Previous, in vivo experiments have shown that an appropriate hormonal environment (high plasma insulin, low plasma glucagon) was unable to induce the accumulation of glucokinase mRNA in term fetal rat liver, whereas it was very efficient in the newly born rat. We have confirmed in the present study that insulin induced the accumulation of glucokinase mRNA in cultured hepatocytes from 1-day-old newborn rats, but not in cultured hepatocytes from 21-day-old fetuses. To identify regulatory regions of the glucokinase gene involved in the insulin response, we have scanned the glucokinase locus for DNase I hypersensitive sites in its in vivo conformation. We confirmed the presence of four liver-specific DNase I hypersensitive sites located in the 5' flanking region of the gene. Moreover, two additional hypersensitive sites, located at 2.5 kb and 3.5 kb upstream of the cap site were found but none of these new sites displayed inducibility by insulin. Finally, an increase of the sensitivity of hypersensitive site-1 and hypersensitive site-2 to DNase I correlates with the ability of insulin to induce glucokinase gene expression in cultured hepatocytes from 1-day-old rats, as observed in previous in vivo studies. This suggests that neither a prior exposure to insulin nor a simple aging of the fetal cells in the presence of the hormone in culture are instrumental for the full DNase-I hypersensitivity of the two proximal sites necessary for the neonatal response of the glucokinase gene to insulin. The proximal hypersensitive site-1, which is close to the transcription start site in the liver, does coincide with a sequence (designated IRSL) that is 80% identical to the phosphoenolpyruvate carboxykinase IRS and with a DNase-I footprint that has been identified overlapping this sequence. Nevertheless, functional analysis of this sequence suggested that it is unlikely that the insulin-response sequence like alone is sufficient to mediate the transcriptional effect of insulin on the hepatic glucokinase gene.


Assuntos
Regulação Enzimológica da Expressão Gênica , Glucoquinase/genética , Insulina/farmacologia , Fígado/efeitos dos fármacos , Sequências Reguladoras de Ácido Nucleico , Animais , Animais Recém-Nascidos , Sequência de Bases , Pegada de DNA , Desoxirribonuclease I/metabolismo , Embrião de Mamíferos/citologia , Indução Enzimática , Glucoquinase/biossíntese , Fígado/citologia , Fígado/enzimologia , Dados de Sequência Molecular , Regiões Promotoras Genéticas/genética , RNA Mensageiro/biossíntese , Ratos , Ratos Wistar , Simplexvirus/genética , Timidina Quinase/genética
11.
Genomics ; 29(3): 740-50, 1995 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-8575768

RESUMO

We cloned and characterized an 83-kb fragment of mouse genomic DNA containing the entire glucokinase (GK) gene. The 11 exons of the gene span a total distance of 49 kb, with exons 1 beta and 1L being separated by 35 kb. A total of 25,266 bp of DNA sequence information was determined: from approximately -9.2 to approximately +15 kb (24,195 bp), relative to the hepatocyte transcription start site, and from -335 to +736 bp (1071 bp), relative to the transcription start site in beta cells. These sequences revealed that mouse GK is > 94% identical to rat and human GK. Mouse hepatic GK mRNA is regulated by fasting and refeeding, as also occurs in the rat. Alignment of the upstream and downstream promoter regions of the mouse, rat, and human genes revealed several evolutionarily conserved regions that may contribute to transcriptional regulation. However, fusion gene studies in transgenic mice indicate that the conserved regions near the transcription start site in hepatocytes are themselves not sufficient for position-independent expression in liver. Analysis of the chromatin structure of a 48-kb region of the mouse gene using DNase I revealed eight liver-specific hypersensitive sites whose locations ranged from 0.1 to 36 kb upstream of the liver transcription start site. The availability of a single, contiguous DNA fragment containing the entire mouse GK gene should allow further studies of cell-specific expression of GK to be performed.


Assuntos
Evolução Biológica , Mapeamento Cromossômico , Glucoquinase/genética , Camundongos/genética , Regiões Promotoras Genéticas , Animais , Sequência de Bases , Clonagem Molecular , Sequência Conservada , DNA/química , DNA/genética , Primers do DNA , Desoxirribonuclease I , Éxons , Regulação Enzimológica da Expressão Gênica , Biblioteca Gênica , Glucoquinase/biossíntese , Humanos , Fígado/enzimologia , Dados de Sequência Molecular , Especificidade de Órgãos , Reação em Cadeia da Polimerase , RNA Mensageiro/biossíntese , Ratos , Proteínas Recombinantes/biossíntese , Homologia de Sequência do Ácido Nucleico , Transcrição Gênica
12.
Eur J Biochem ; 215(3): 883-92, 1993 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-8354293

RESUMO

Glucokinase first appears in the liver of the rat 2 weeks after birth and its activity rapidly increases after weaning on to a high-carbohydrate diet. The appearance of glucokinase is principally due to the increase of plasma insulin and to the decrease of plasma glucagon concentrations. Oral glucose administration to 1- or 10-day-old suckling rats induced an increase in plasma insulin and a fall in plasma glucagon and allowed a rapid accumulation of liver glucokinase mRNA, secondarily to a stimulation of gene transcription. When unrestrained late pregnant rats were infused with glucose during 36 h to induce an increase in fetal plasma insulin and a decrease in fetal plasma glucagon concentrations, glucokinase mRNA was detectable in fetal liver but the level was 100-fold lower than that observed in 1- or 10-day-old suckling rats. It is suggested that the hormonal environment did not allow glucokinase gene expression to be induced in fetal liver and that the absence of expression of glucokinase in suckling rat liver is due to the presence of low plasma insulin and high plasma glucagon levels. The chromatin structure of the glucokinase gene was examined during development by identification of DNase-I-hypersensitive sites from the region comprised between -8 kb upstream and +4 kb downstream of the cap site. Five hypersensitive sites were found: four liver-specific sites upstream of the cap site and one non-specific site in the first intron. These sites are already present in term fetus but the intensity of the two proximal sites located upstream of the cap site increase markedly after birth. This suggests that these sites could be implicated in the regulation of glucokinase gene expression by insulin and glucagon. Full DNase-I-hypersensitivity of these two proximal sites seems necessary for the mature response of glucokinase gene in response to changes in pancreatic hormones concentrations.


Assuntos
Glucoquinase/biossíntese , Glucose/farmacologia , Fígado/enzimologia , Animais , Animais Recém-Nascidos , Cromatina , Desoxirribonuclease I/metabolismo , Indução Enzimática/efeitos dos fármacos , Feminino , Feto/metabolismo , Expressão Gênica/efeitos dos fármacos , Glucagon/sangue , Glucoquinase/genética , Insulina/sangue , Fígado/efeitos dos fármacos , Masculino , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Transcrição Gênica
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