984 resultados para Bone Metabolism
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BACKGROUND/OBJECTIVES Aging enhances frequency of chronic diseases like cardiovascular diseases or periodontitis. Here we reproduced an age-dependent model of the periodontium, a fully physiological approach to periodontal conditions, to evaluate the impact of dietary fat type on gingival tissue of young (6 months old) and old (24 months old) rats. METHODS/FINDINGS Animals were fed life-long on diets based on monounsaturated fatty acids (MUFA) as virgin olive oil, n-6 polyunsaturated fatty acids (n-6PUFA), as sunflower oil, or n-3PUFA, as fish oil. Age-related alveolar bone loss was higher in n-6PUFA fed rats, probably as a consequence of the ablation of the cell capacity to adapt to aging. Gene expression analysis suggests that MUFA or n-3PUFA allowed mitochondria to maintain an adequate turnover through induction of biogenesis, autophagy and the antioxidant systems, and avoiding mitochondrial electron transport system alterations. CONCLUSIONS The main finding is that the enhanced alveolar bone loss associated to age may be targeted by an appropriate dietary treatment. The mechanisms involved in this phenomenon are related with an ablation of the cell capacity to adapt to aging. Thus, MUFA or n-3PUFA might allow mitochondrial maintaining turnover through biogenesis or autophagy. They might also be able to induce the corresponding antioxidant systems to counteract age-related oxidative stress, and do not inhibit mitochondrial electron transport chain. From the nutritional and clinical point of view, it is noteworthy that the potential treatments to attenuate alveolar bone loss (a feature of periodontal disease) associated to age could be similar to some of the proposed for the prevention and treatment of cardiovascular diseases, a group of pathologies recently associated with age-related periodontitis.
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Sphingomonas wittichii RW1 is a bacterium isolated for its ability to degrade the xenobiotic compounds dibenzodioxin and dibenzofuran (DBF). A number of genes involved in DBF degradation have been previously characterized, such as the dxn cluster, dbfB, and the electron transfer components fdx1, fdx3, and redA2. Here we use a combination of whole genome transcriptome analysis and transposon library screening to characterize RW1 catabolic and other genes implicated in the reaction to or degradation of DBF. To detect differentially expressed genes upon exposure to DBF, we applied three different growth exposure experiments, using either short DBF exposures to actively growing cells or growing them with DBF as sole carbon and energy source. Genome-wide gene expression was examined using a custom-made microarray. In addition, proportional abundance determination of transposon insertions in RW1 libraries grown on salicylate or DBF by ultra-high throughput sequencing was used to infer genes whose interruption caused a fitness loss for growth on DBF. Expression patterns showed that batch and chemostat growth conditions, and short or long exposure of cells to DBF produced very different responses. Numerous other uncharacterized catabolic gene clusters putatively involved in aromatic compound metabolism increased expression in response to DBF. In addition, only very few transposon insertions completely abolished growth on DBF. Some of those (e.g., in dxnA1) were expected, whereas others (in a gene cluster for phenylacetate degradation) were not. Both transcriptomic data and transposon screening suggest operation of multiple redundant and parallel aromatic pathways, depending on DBF exposure. In addition, increased expression of other non-catabolic genes suggests that during initial exposure, S. wittichii RW1 perceives DBF as a stressor, whereas after longer exposure, the compound is recognized as a carbon source and metabolized using several pathways in parallel.
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During the last decade, the development of "bedside" investigative methods, including indirect calorimetry, nutritional balance and stable isotope techniques, have given a new insight into energy and protein metabolism in the neonates. Neonates and premature infants especially, create an unusual opportunity to study the metabolic adaptation to extrauterine life because their physical environment can be controlled, their energy intake and energy expenditure can be measured and the link between their protein metabolism and the energetics of their postnatal growth can be assessed with accuracy. Thus, relatively abstract physiological concepts such as the postnatal timecourse of heat production, energy cost of growth, energy cost of physical activity, thermogenic effect of feeding, efficiency of protein gain, metabolic cost of protein gain and protein turnover have been quantified. These results show that energy expenditure and heat production rates increase postnatally from average values of 40 kcal/kgxday during the first week to 60 kcal/kgxday in the third week. This increase parellels nutritional intakes as well as the rate of weight gain. The thermogenic effect of feeding and the physical activity are relatively low and account only for an average of 5% each of the total heat production. The cost of protein turnover is the highest energy demanding process. The fact that nitrogen balance becomes positive within 72 hours after birth places the newborn in a transitional situation of dissociated balance between energy and protein metabolism: dry body mass and fat decrease while there is a gain in protein and increase in supine length. This particular situation ends during the second postnatal week and soon thereafter the rate of weight gain matches the statural growth. The goals of the following review are to summarize recent data on the physiological aspects of energy and protein metabolism directly related to the extrauterine adaptation, to describe experimental approaches which recently were adapted to the newborns in order to get "bedside results" and to discuss how far these results can help everyday's neonatal practice.
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INTRODUCTION For critically patients, enteral immunonutrition results in notable reductions in infections and in length of stay in hospital, but not on mortality, raising the question as to whether this relate to the heterogeneous nature of critically ill patients or to the absence of the altered absorption of specific nutrients within the immunonutrient mix (e.g. iron). Immune-associated functional iron deficiency (FID) is not only one of the many causes or anaemia in the critically ill, but also a cause of inappropriate immune response, leading to a longer duration of episodes of systemic inflammatory response syndrome and poor outcome. OBJECTIVE This prospective cross-sectional study was undertaken to assess the prevalence of FID in critically ill patients during their stay in intensive care (ICU) in order to find the more appropriate population of patients that can benefit from iron therapy. METHOD Full blood cell counts, including reticulocytes (RETIC), serum iron (SI), transferring levels (TRF) and saturation (satTRF), serum TFR receptor (sTfR), ferritin (FRT) and C-reactive protein (CRP) were measured in venous blood samples from 131 random patients admitted to the ICU for at least 24 h (Length of ICU stay, LIS; min: 1 day; max: 38 days). RESULTS Anaemia (Hb < 12 g/dL) was present in 76% of the patients (Hb < 10 g/dL in 33%), hypoferremia (SI < 45 microg/dl) in 69%; satTRF < 20% in 53%; FRT < 100 ng/mL in 23%; sTfR > 2.3 mg/dL in 13%; and CRP > 0.5 mg/dL in 88%. Statistically significant correlations (r of Pearson; *p < 0.05, **p < 0.01) were obtained for serum CRP levels and WBC**, Hb*, TRF**, satTRF*, and FRT**. There was also a strong correlation between TRF and FRT (-0.650**), but not between FRT and satTRF or SI. LIS correlated with Hb*, CRP**, TRF*, satTRF* and FRT**. CONCLUSIONS A large proportion of critically ill patients admitted to the ICU presented the typical functional iron deficiency (FID) of acute inflammation-related anaemia (AIRA). This FID correlates with the inflammatory status and the length of stay at the ICU. However, 21% of the ICU patients with AIRA had an associated real iron deficiency (satTRF < 20; FRT < 100 and sTfR > 2.3). Since oral supplementation of iron seems to be ineffective, all these patients might benefit of iv iron therapy for correction of real or functional iron deficiency, which in turn might help to ameliorate their inflammatory status.
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Low-grade osteosarcoma is a rare malignancy that may be subdivided into two main subgroups on the basis of location in relation to the bone cortex, that is, parosteal osteosarcoma and low-grade central osteosarcoma. Their histological appearance is quite similar and characterized by spindle cell stroma with low-to-moderate cellularity and well-differentiated anastomosing bone trabeculae. Low-grade osteosarcomas have a simple genetic profile with supernumerary ring chromosomes comprising amplification of chromosome 12q13-15, including the cyclin-dependent kinase 4 (CDK4) and murine double-minute type 2 (MDM2) gene region. Low-grade osteosarcoma can be confused with fibrous and fibro-osseous lesions such as fibromatosis and fibrous dysplasia on radiological and histological findings. We investigated MDM2-CDK4 immunohistochemical expression in a series of 72 low-grade osteosarcomas and 107 fibrous or fibro-osseous lesions of the bone or paraosseous soft tissue. The MDM2-CDK4 amplification status of low-grade osteosarcoma was also evaluated by comparative genomic hybridization array in 18 cases, and the MDM2 amplification status was evaluated by fluorescence in situ hybridization or quantitative real-time polymerase chain reaction in 31 cases of benign fibrous and fibro-osseous lesions. MDM2-CDK4 immunostaining and MDM2 amplification by fluorescence in situ hybridization or quantitative real-time polymerase chain reaction were investigated in a control group of 23 cases of primary high-grade bone sarcoma, including 20 conventional high-grade osteosarcomas, two pleomorphic spindle cell sarcomas/malignant fibrous histiocytomas and one leiomyosarcoma. The results showed that MDM2 and/or CDK4 immunoreactivity was present in 89% of low-grade osteosarcoma specimens. All benign fibrous and fibro-osseous lesions and the tumors of the control group were negative for MDM2 and CDK4. These results were consistent with the MDM2 and CDK4 amplification results. In conclusion, immunohistochemical expression of MDM2 and CDK4 is specific and provides sensitive markers for the diagnosis of low-grade osteosarcomas, helping to differentiate them from benign fibrous and fibro-osseous lesions, particularly in cases with atypical radio-clinical presentation and/or limited biopsy samples.
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RÉSUMÉ : Le traitement répété à la phencyclidine (PCP), un bloqueur du récepteur NMDA (NMDAR), reproduit chez les rongeurs une partie de la symptomatologie typique de la schizophrénie. Le blocage prolongé du NMDAR par la PCP mime une hypofunction du NMDAR, une des principales altérations supposées exister dans les cerveaux des patients schizophréniques. Le but de notre étude était d'examiner les conséquences neurochimiques, métaboliques et fonctionnelles du traitement répété à la phencyclidine in vivo, au niveau du cortex préfrontal (cpf), une région cérébrale qui joue un rôle dans les déficits cognitifs observés chez les patients schizophréniques. Pour répondre à cette question, les rats ou les souris ont reçu chaque jour une injection soit de PCP (5 mg/kg), soit de solution saline, pendant 7 ou 14 jours. Les animaux ont ensuite été sacrifiés au moins 24 heures après le dernier traitement. Des tranches aiguës du cpf ont été préparées rapidement, puis stimulées avec une concentration élevée de KCI, de manière à induire une libération de glutamate à partir des terminaisons synaptiques excitatrices. Les résultats montrent que les tranches du cpf des animaux traités à la PCP ont libéré une quantité de glutamate significativement inférieure par rapport à celles des animaux contrôle. Ce déficit de libération a persisté 72 heures après la fin du traitement, tandis qu'il n'était pas observé dans le cortex visuel primaire, une autre région corticale. En outre, le traitement avec des antipsychotiques, l'halopéridol ou l'olanzapine, a supprimé le déficit induit par la PCP. Le même déficit de libération a été remarqué sur des synaptosomes obtenus à partir du cpf des animaux traités à la phenryclidine. Cette observation indique que la PCP induit une modification plastique adaptative du mécanisme qui contrôle la libération du glutamate dans les terminaisons synaptiques. Nous avons découvert que cette modification implique la sous-régulation d'un NMDAR présynaptique, qui serait doué d'un rôle d'autorécepteur stimulateur de la libération du glutamate. Grâce à des tests comportementaux conduits en parallèle et réalisés pour évaluer la fonctionnalité du cpf, nous avons observé chez les souris traitées à la PCP une flexibilité comportementale réduite lors d'un test de discrimination de stimuli visuels/tactiles. Le déficit cognitif était encore présent 4 jours après la dernière administration de PCP. La technique de l'autoradiographie quantitative du [14C]2-deoxyglucose a permis d'associer ce déficit à une réduction de l'activité métabolique cérébrale pendant le déroulement du test, particulièrement au niveau du cpf. Dans l'ensemble, nos résultats suggèrent que le blocage prolongé du NMDAR lors de l'administration répétée de PCP produit un déficit de libération du glutamate au niveau des terminaisons synaptiques excitatrices du cpf. Un tel déficit pourrait être provoqué par la sousrégulation d'un NMDAR présynaptique, qui aurait une fonction de stimulateur de libération; la transmission excitatrice du cpf s'en trouverait dans ce cas réduite. Ce résultat est en ligne avec l'activité métabolique et fonctionnelle réduite du cpf et l'observation de déficits cognitifs induits lors de l'administration de la PCP. ABSTRACT : Sub-chronic treatment with phencyclidine (PCP), an NMDA receptor (NMDAR) channel blocker, reproduces in rodents part of the symptomatology associated to schizophrenia in humans. Prolonged pharmacological blockade of NMDAR with PCP mimics NMDAR hypofunction, one of the main alterations thought to take place in the brains of schizophrenics. Our study was aimed at investigating the neurochemical, metabolic and behavioral consequences of repeated PCP administration in vivo, focusing on the functioning of the prefrontal cortex (pfc), a brain region highly relevant for the cognitive deficits observed in schizophrenic patients. Rats or mice received a daily administration of either PCP (5 mg/kg) or saline for 7 or 14 days. At least 24 hours after the last treatment the animals were sacrificed. Acute slices of the pfc were quickly prepared and challenged with high KCl to induce synaptic glutamate release. Pfc slices from PCP-treated animals released significantly less glutamate than slices from salinetreated animals. The deficit persisted 72 hours after the end of the treatment, while it was not observed in another cortical region: the primary visual cortex. Interestingly, treatment with antipsychotic drugs, either haloperidol or olanzapine, reverted the glutamate release defect induced by PCP treatment. The same release defect was observed in synaptosomes prepared from the pfc of PCP-treated animals, indicating that PCP induces a plastic adaptive change in the mechanism controlling glutamate release in the glutamatergic terminals. We discovered that such change most likely involves the down-regulation of a newly identified, pre-synaptic NMDAR with stimulatory auto-receptor function on glutamate release. In parallel sets of behavioral experiments challenging pfc function, mice sub-chronically treated with PCP displayed reduced behavioral flexibility (reversal learning) in a visual/tactile-cued discrimination task. The cognitive deficit was still evident 4 days after the last PCP administration and was associated to reduced brain metabolic activity during the performance of the behavioral task, notably in the pfc, as determined by [14C]2-deoxyglucose quantitative autoradiography. Clverall, our findings suggest that prolonged NMDAR blockade by repeated PCP administration results in a defect of glutamate release from excitatory afferents in the pfc, possibly ascribed to down-regulation of apre-synaptic stimulatory NMDAR. Deficient excitatory neurotransmission in the pfc is consistent with the reduced metabolic and functional activation of this area and the observed PCP-induced cognitive deficits.
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The expression of DNA topoisomerase II alpha and beta genes was studied in murine normal tissues. Northern blot analysis using probes specific for the two genes showed that the patterns of expression were different among 22 tissues of adult mice. Expression levels of topoisomerase II alpha gene were high in proliferating tissues, such as bone marrow and spleen, and undetectable or low in 17 other tissues. In contrast, high or intermediate expression of topoisomerase II beta gene was found in a variety of tissues (15) of adult mice, including those with no proliferating cells. Topoisomerase II gene expression was also studied during murine development. In whole embryos both genes were expressed at higher levels in early than late stages of embryogenesis. Heart, brain and liver of embryos two days before delivery, and these same tissues plus lung and thymus of newborn (1-day-old) mice expressed appreciable levels of the two genes. Interestingly, a post-natal induction of the beta gene expression was observed in the brain but not in the liver; conversely, the expression of the alpha gene was increased 1 day after birth in the liver but not in the brain. However, gene expression of a proliferation-associated enzyme, thymidylate synthase, was similar in these tissues between embryos and newborns. Thus, the two genes were differentially regulated in the post-natal period, and a tissue-specific role may be suggested for the two isoenzymes in the development of differentiated tissues such as the brain and liver. Based on the differential patterns of expression of the two isoforms, this analysis indicates that topoisomerase II alpha may be a specific marker of cell proliferation, whereas topoisomerase II beta may be implicated in functions of DNA metabolism other than replication.
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Inflammation is a protective attempt by the host to remove injurious stimuli and initiate the tissue healing process. The inflammatory response must be actively terminated, however, because failure to do so can result in 'bystander' damage to tissues and diseases such as arthritis or type-2 diabetes. Yet the mechanisms controlling excessive inflammatory responses are still poorly understood. Here we show that mouse effector and memory CD4(+) T cells abolish macrophage inflammasome-mediated caspase-1 activation and subsequent interleukin 1beta release in a cognate manner. Inflammasome inhibition is observed for all tested NLRP1 (commonly called NALP1) and NLRP3 (NALP3 or cryopyrin) activators, whereas NLRC4 (IPAF) inflammasome function and release of other inflammatory mediators such as CXCL2, interleukin 6 and tumour necrosis factor are not affected. Suppression of the NLRP3 inflammasome requires cell-to-cell contact and can be mimicked by macrophage stimulation with selected ligands of the tumour necrosis factor family, such as CD40L (also known as CD40LG). In a NLRP3-dependent peritonitis model, effector CD4(+) T cells are responsible for decreasing neutrophil recruitment in an antigen-dependent manner. Our findings reveal an unexpected mechanism of inflammasome inhibition, whereby effector and memory T cells suppress potentially damaging inflammation, yet leave the primary inflammatory response, crucial for the onset of immunity, intact.
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PURPOSE: Retinal degeneration is associated with iron accumulation in several rodent models in which iron-regulating proteins are impaired. Oxidative stress is catalyzed by unbound iron. METHODS: The role of the heavy chain of ferritin, which sequesters iron, in regulating the thickness of the photoreceptor nuclear layer in the 4- and 16-month-old wild-type H ferritin (HFt(+/+)) and heterozygous H ferritin (HFt(+/-)) mice was investigated, before and 12 days after exposure to 13,000-lux light for 24 hours. The regulation of gene expression of the various proteins involved in iron homeostasis, such as transferrin, transferrin receptor, hephaestin, ferroportin, iron regulatory proteins 1 and 2, hepcidin, ceruloplasmin, and heme-oxygenase 1, was analyzed by quantitative (q)RT-PCR during exposure (2, 12, and 24 hours) and 24 hours after 1 day of exposure in the 4-month-old HFt(+/+) and HFt(+/-) mouse retinas. RESULTS: Retinal degeneration in the 4-month-old HFt(+/-) mice was more extensive than in the HFt(+/+) mice. Yet, it was more extensive in both of the 16-month-old mouse groups, revealing the combined effect of age and excessive light. Injury caused by excessive light modified the temporal gene expression of iron-regulating proteins similarly in the HFt(+/-) and HFt(+/+) mice. CONCLUSIONS: Loss of one allele of H ferritin appears to increase light-induced degeneration. This study highlighted that oxidative stress related to light-induced injury is associated with major changes in gene expression of iron metabolism proteins.
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Mouse interleukin 3 (IL-3) cDNA was cloned into a plasmid construction, allowing the synthesis of very high quantities of IL-3 in Escherichia coli. The recombinant (r) IL-3, purified to homogeneity, was active in vitro on the proliferation and differentiation of various hematopoietic progenitor cells at 1 pM. To maintain detectable blood levels of IL-3, osmotic pumps containing rIL-3 or control solutions were placed under the skin of normal and irradiated C3H/HeJ and (BALB X B10) F1 mice. The effect of IL-3 on hematopoietic progenitor cell numbers in spleen and bone marrow was evaluated 3 and 7 days later by using an in vitro clonal assay. The results demonstrated the following: (i) Doses of IL-3 infused at the rate of 2.5-5 ng per g of body weight per hr were sufficient to increase the numbers of hematopoietic progenitors in normal mice by at least 2-fold within 3 days. (ii) In mice with progenitor cell levels depressed by sublethal irradiation, 7-day treatment with IL-3 resulted in a 10-fold increase to near normal levels. (iii) The erythroid and myeloid lineages appeared to be enhanced to the same extent. (iv) Enhancement of hematopoiesis occurred primarily in spleen, but hematopoietic foci were also evident in the liver; in contrast, total cell and progenitor cell numbers were decreased in the bone marrow.
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In Pseudomonas aeruginosa, the catabolite repression control (Crc) protein repressed the formation of the blue pigment pyocyanin in response to a preferred carbon source (succinate) by interacting with phzM mRNA, which encodes a key enzyme in pyocyanin biosynthesis. Crc bound to an extended imperfect recognition sequence that was interrupted by the AUG translation initiation codon.
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INTRODUCTION: Alterations in lipid metabolism and bone mineral metabolism disturbances are common disorders among renal transplant patients, contributing to the apparition of oxidative metabolic and cardiovascular diseases that threaten the integrity of the graft. AIMS: Describe and observe the evolution of alterations in bone mineral density (BMD) and lipid abnormalities in a population of kidney transplant patients. MATERIAL AND METHOD: The samples consisted of 119 kidney transplant patients of both sexes, measurements were performed pretransplant and posttransplant for five years of biochemical parameters, anthropometric measurements and measurement of bone mineral density at the lumbar spine, femur and radioulnar. RESULTS: During the five years after transplantation a significant increase in biochemical parameters, BMI, dyslipidemia, diabetes and hypertension occurs. At six months there is a high percentage of patients with pathologic BMD increase by 4.1% per year of transplantation. CONCLUSIONS: After kidney transplantation, a large increase of hyperlipidemia associated with a characteristic pattern of altered lipid with elevated total cholesterol, low density lipoprotein, high density lipoprotein, and the resulting increase in triglycerides, occurs despite statin therapy, leading to an increase in risk factors for diabetes, hypertension, diseases and cardiovascualres further loss of bone mass which carries a high risk of serious fractures occurs, threatening kidney graft and quality of life of patients.
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Critical limb ischemia in diabetic patients is associated with high rates of morbidity and mortality. Suboptimal responses to the available medical and surgical treatments are common in these patients, who also demonstrate limited vascular homeostasis. Neovasculogenesis induced by stem cell therapy could be a useful approach for these patients. Neovasculogenesis and clinical improvement were compared at baseline and at 3 and 12 months after autologous bone marrow-derived mononuclear cell (BMMNC) transplantation in diabetic patients with peripheral artery disease. We conducted a prospective study to evaluate the safety and efficacy of intra-arterial administration of autologous BMMNCs (100-400 × 10(6) cells) in 20 diabetic patients with severe below-the-knee arterial ischemia. Although the time course of clinical effects differed among patients, after 12 months of follow-up all patients presented a notable improvement in the Rutherford-Becker classification, the University of Texas diabetic wound scales, and the Ankle-Brachial Index in the target limb. The clinical outcome was consistent with neovasculogenesis, which was assessed at 3 months by digital subtraction angiography and quantified by MetaMorph software. Unfortunately, local cell therapy in the target limb had no beneficial effect on the high mortality rate in these patients. In diabetic patients with critical limb ischemia, intra-arterial perfusion of BMMNCs is a safe procedure that generates a significant increase in the vascular network in ischemic areas and promotes remarkable clinical improvement.