RESUMEN
Bone scans, reflecting blood flow and metabolic activity in a region of interest, are frequently used to evaluate mandibular growth disorders. Increased uptake is a non-specific finding and can occur as a result of multiple causes. The correlation between radioactive tracer uptake and growth activity has not been consistently demonstrated. The aim of this study was to assess the accuracy of planar skeletal scintigraphy (SS), single-photon emission computed tomography (SPECT), and SPECT with computed tomography (CT) images (SPECT/CT) in detecting abnormal mandibular growth activity compared to clinical and radiographic/tomographic methods (reference standard) and histologic findings. A systematic review was conducted following the PRISMA guidelines. Sensitivity, specificity, and accuracy were calculated for planar SS, SPECT, and SPECT/CT. Compared to the reference standard, SPECT/CT had the best diagnostic accuracy (76.5% sensitivity, 90.4% specificity, 83.2% accuracy), followed by planar SS (81.8% sensitivity, 84.5% specificity, 83.0% accuracy) and SPECT (77.7% sensitivity, 72.4% specificity, 74.5% accuracy). The results of this study indicate that SPECT/CT has the best clinical correlation, but the certainty of the evidence is low. The differences in sensitivity and specificity between the three index tests were not clinically significant. The three tests can be useful, with only a small difference in their diagnostic value. Histopathology was found not to be satisfactory as a reference standard.
Asunto(s)
Mandíbula , Cintigrafía , Sensibilidad y Especificidad , Tomografía Computarizada de Emisión de Fotón Único , Humanos , Mandíbula/diagnóstico por imagen , Tomografía Computarizada de Emisión de Fotón Único/métodos , Radiofármacos , Tomografía Computarizada por Tomografía Computarizada de Emisión de Fotón ÚnicoRESUMEN
Due to the presence of the renin-angiotensin system (RAS) in tissues and its specific influence on white adipose tissue, fat cells are possible targets of pharmacological RAS blockers commonly used as anti-hypertensive drugs. In the present study, we investigated the effects of different RAS blockers on fat cell metabolism, more specifically on lipolysis, lipogenesis and oxidation of energy substrates. Isolated primary adipocytes were incubated with different RAS blockers (aliskiren, captopril and losartan) in vitro for 24 h and lipolysis, lipogenesis and glucose oxidation capacities were determined in dose-response assays to a β-adrenergic agonist and to insulin. Although no change was found in lipolytic capacity, the RAS blockers modulated lipogenesis and glucose oxidation in a different way. While captopril decreased insulin-stimulated lipogenesis (−19% of maximal response and −60% of insulin responsiveness) due to reduced glucose derived glycerol synthesis (−19% of maximal response and 64% of insulin responsiveness), aliskiren increased insulin-stimulated glucose oxidation (+49% of maximal response and +292% of insulin responsiveness) in fat cells. Our experiments demonstrate that RAS blockers can differentially induce metabolic alterations in adipocyte metabolism, characterized by a reduction in lipogenic responsiveness or an increase in glucose oxidation. The impact of RAS blockers on adipocyte metabolism may have beneficial implications on metabolic disorders during their therapeutic use in hypertensive patients.
Asunto(s)
Animales , Masculino , Sistema Renina-Angiotensina/efectos de los fármacos , Adipocitos/efectos de los fármacos , Antihipertensivos/farmacología , Captopril/farmacología , Ratas Wistar , Adipocitos/metabolismo , Losartán/farmacología , Lipogénesis/efectos de los fármacos , Fumaratos/farmacología , Amidas/farmacología , Glucosa/metabolismo , Glicerol/metabolismo , Lipólisis/efectos de los fármacosRESUMEN
As it is a common observation that obesity tends to occur after discontinuation of exercise, we investigated how white adipocytes isolated from the periepididymal fat of animals with interrupted physical training transport and oxidize glucose, and whether these adaptations support the weight regain seen after 4 weeks of physical detraining. Male Wistar rats (45 days old, weighing 200 g) were divided into two groups (n=10): group D (detrained), trained for 8 weeks and detrained for 4 weeks; and group S (sedentary). The physical exercise was carried out on a treadmill for 60 min/day, 5 days/week for 8 weeks, at 50-60% of the maximum running capacity. After the training protocol, adipocytes isolated from the periepididymal adipose tissue were submitted to glucose uptake and oxidation tests. Adipocytes from detrained animals increased their glucose uptake capacity by 18.5% compared with those from sedentary animals (P<0.05). The same cells also showed a greater glucose oxidation capacity in response to insulin stimulation (34.55%) compared with those from the S group (P<0.05). We hypothesize that, owing to the more intense glucose entrance into adipose cells from detrained rats, more substrate became available for triacylglycerol synthesis. Furthermore, this increased glucose oxidation rate allowed an increase in energy supply for triacylglycerol synthesis. Thus, physical detraining might play a role as a possible obesogenic factor for increasing glucose uptake and oxidation by adipocytes.
Asunto(s)
Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Enfermedades de los Trabajadores Agrícolas/inducido químicamente , Exposición Profesional/efectos adversos , Enfermedad de Parkinson Secundaria/inducido químicamente , Plaguicidas/toxicidad , California , Estudios de Casos y Controles , Modelos Estadísticos , Exposición Profesional/estadística & datos numéricos , Puntaje de Propensión , Factores de RiesgoRESUMEN
Numerous studies address the physiology of adipose tissue (AT). The interest surrounding the physiology of AT is primarily the result of the epidemic outburst of obesity in various contemporary societies. Briefly, the two primary metabolic activities of white AT include lipogenesis and lipolysis. Throughout the last two decades, a new model of AT physiology has emerged. Although AT was considered to be primarily an abundant energy source, it is currently considered to be a prolific producer of biologically active substances, and, consequently, is now recognized as an endocrine organ. In addition to leptin, other biologically active substances secreted by AT, generally classified as cytokines, include adiponectin, interleukin-6, tumor necrosis factor-alpha, resistin, vaspin, visfatin, and many others now collectively referred to as adipokines. The secretion of such biologically active substances by AT indicates its importance as a metabolic regulator. Cell turnover of AT has also recently been investigated in terms of its biological role in adipogenesis. Consequently, the objective of this review is to provide a comprehensive critical review of the current literature concerning the metabolic (lipolysis, lipogenesis) and endocrine actions of AT.
Asunto(s)
Animales , Humanos , Ratones , Ratas , Adipocitos/metabolismo , Adipogénesis/fisiología , Tejido Adiposo Blanco/fisiología , Lipólisis/fisiología , Obesidad/fisiopatología , Adipoquinas/metabolismo , Citocinas/metabolismo , Leptina/metabolismo , Nicotinamida Fosforribosiltransferasa/metabolismo , Resistina/metabolismo , Transducción de Señal/fisiologíaRESUMEN
La obtención de tejido adiposo supone un nuevo y prometedor mercado de trabajo para los cirujanos plásticos, ya que los bancos de tejidos escogerán de forma acertada la grasa como el medio más fácil para obtener fuentes de células madre de alto rendimiento, en la medida en que este tejido es capaz de producir al menos cinco veces más unidades formadores de colonias (UFCs) que la médula ósea. El objetivo del presente trabajo es mostrar lo que se puede esperar del tejido adiposo como origen de células adultas de fracción vacularestromal (FVE), y señalar las mejores áreas del cuerpo humano para ser elegidas como donantes de tejido adiposo, extraído mediante liposucción. Describimos la rutina seguida para la obtención de células de FVE mediante la digestión de las muestras de tejido adiposo humano con colagenasa. En el momento de su recolección, esas células presentaban una viabilidad de 92+/- 1% basada en exclusión por Azul de Trypan. Las células de FVE recontadas después de permanecer48 horas en medio de cultivo de Eagle modificado por Dulbecco(DMEM), dentro de una cámara de Neubauer, tras lo cual el rendimiento medio de las células de FVE fue de 7,2 +/- 1,3 x 103células por mililitro de tejido lipoaspirado. En conclusión, pensamos que supone un desafío en la actualida del mejorar las estrategias para la obtención de células de FVE. Este trabajo, por ahora preliminar, muestra que las células de FVE pueden ser fácilmente obtenidas por medio de lipoaspiración. La comparación entre las diferentes áreas donantes, mostró un rendimiento22% más alto para las células de FVE cuando el tejido adiposo había sido obtenido del tronco, en comparación a cuando lo había sido delos miembros (AU)
The harvest of adipose tissue will be a promising labor marketing for plastic surgeons, since tissue banks will certainly choose fat as the easiest way to obtain a high-yield source of stem cells, as this type of tissue can produce at least five times more colony-forming units (CFUs) than bone marrow extracts. The aim of this study is to show what can be expected from fat tissues as an origin of adult stromal vascular fraction (SVF) cells, and to evaluate the best areas to be elected as donor sites within the human body, all obtained by liposuction. The routine to obtain SVF cells by collagenase digestion of human adipose tissue samples was described. At the time of harvest, these cells displayed a viability of 92+/- 1% based on Try pan Blue exclusion, SVF cells were counted after 48 hours culture in Dulbecco´s modified Eagle medium (DMEM) in a Neuberger counting chamber. The average yield of SVF cells was 7,2 +/- 1,3 x 103 cells per millilitre of liposuctioned tissue. As a conclusion, best strategies to obtain SVF cells are an important challenge nowadays. This study, although preliminary, showed that SVF may be easily obtained From liposuction. Comparison among different donor sites showed a 22% higher yield of SVF cells when fat tissue had been obtained from the trunk regions, when confronted with limbs (AU)
Asunto(s)
Células Madre/fisiología , Topografía Médica/métodos , Tejido Adiposo/citología , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/ultraestructura , Células Madre/citología , Lipectomía/tendencias , Tejido Adiposo , Grosor de los Pliegues Cutáneos , Mesodermo/citología , Lipectomía/educación , Lipectomía/métodosRESUMEN
The OB protein, also known as leptin, is secreted by adipose tissue, circulates in the blood, probably bound to a family of binding proteins, and acts on central neural networks regulating ingestive behavior and energy balance. The two forms of leptin receptors (long and short forms) have been identified in various peripheral tissues, a fact that makes them possible target sites for a direct action of leptin. It has been shown that the OB protein interferes with insulin secretion from pancreatic islets, reduces insulin-stimulated glucose transport in adipocytes, and increases glucose transport, glycogen synthesis and fatty acid oxidation in skeletal muscle. Under normoglycemic and normoinsulinemic conditions, leptin seems to shift the flux of metabolites from adipose tissue to skeletal muscle. This may function as a peripheral mechanism that helps control body weight and prevents obesity. Data that substantiate this hypothesis are presented in this review
Asunto(s)
Humanos , Animales , Ratones , Ratas , Tejido Adiposo/metabolismo , Insulina/metabolismo , Islotes Pancreáticos/metabolismo , Músculo Esquelético/metabolismo , Proteínas/fisiología , Adipocitos , Peso Corporal , Proteínas Portadoras/fisiología , ObesidadRESUMEN
The time-course changes of the responsiveness of glycogen breakdown to a- and Beta-adrenergic agonists during insulin-induced hypoglycemia (IIH) were investigated. Blood glucose levels were decreased prior to the alteration in the hepatic responsiveness to adrenergic agonists. The activation of hepatic glucose production and glycogenolysis by phenylephrine (2 µM) and isoproterenol (20 µM) was decreased in IIH. The changes in the responsiveness of glycogen catabolism were first observed for isoproterenol and later for phenylephrine. Hepatic ß-adrenergic receptors showed a higher degree of adrenergic desensitization than did a-receptors. Liver glycogen synthase activity, glycogen content and the catabolic effect of dibutyryl cyclic AMP (the Beta-receptor second messenger) were not affected by IIH.
Asunto(s)
Animales , Masculino , Ratas , Agonistas Adrenérgicos/farmacología , Bucladesina/farmacología , Hipoglucemia/metabolismo , Glucógeno Hepático/metabolismo , Hígado/efectos de los fármacos , Agonistas alfa-Adrenérgicos/farmacología , Glucosa/biosíntesis , Glucólisis/efectos de los fármacos , Hipoglucemia/inducido químicamente , Inyecciones Intraperitoneales , Insulina/administración & dosificación , Isoproterenol/farmacología , Fenilefrina/farmacología , Ácido Pirúvico/metabolismo , Ratas Wistar , Factores de TiempoRESUMEN
A leptina e uma proteina produzida e secretada pelo tecido adiposo, que possui efeito supressor da ingestao alimentar agindo no hipotalamo. Recentemente, alguns autores demostraram efeitos perifericos da leptina e formularam a hipotese desta funcionar tambem como hormonio contra regulador da insulina...
Asunto(s)
Animales , Masculino , Ratas , Glucemia/metabolismo , Adipocitos/efectos de los fármacos , Músculo Esquelético/metabolismo , Tejido Adiposo/metabolismo , Ratas WistarRESUMEN
We determined the response of glucose transport to insulin in isolated adipocytes and the lipogenic activity of insulin in fragments of epididymal adipose tissue obtained from male MSG-obese rats. Basal glucose transport rates (pmol 3 min-1 10(5) cells-1) were 100 higher in MSG than in control cells (3-month old male Wistar rats) pre-incubated for 30 min (P < 0.01). Nevertheless, when expressed as fmol 3 min-1 microns 2 cell surface area-1, transport rates were similar for the two groups (31.2 +/- 2.6 for MSG and 26.5 +/- 3.2 for controls, N = 7). No differences were observed in maximally insulin-stimulated glucose transport rates between groups (72.6 +/- 10.6 for MSG and 101.0 +/- 12.0 for controls, N = 7). In contrast, for adipocytes pre-incubated for 2 h, the basal uptake rates were 3.7 times higher and the maximal response to insulin was 103 higher in cells from MSG rats compared to control cells. These alterations in MSG rat adipocytes were accompanied by changes in cell sensitivity to insulin (EC50, 0.13 +/- 0.02 ng/ml for MSG vs 0.46 +/- 0.10 ng/ml for controls, P < 0.01). The rates of incorporation of labelled substrates (3H2O and 14C-glucose) into total lipids showed that in vitro lipogenesis was also 79 (3H2O) and 250 (14C-glucose) higher in MSG adipose tissue fragments. The MSG animals were consistently hyperinsulinemic. These data suggest that the obesity of 3-month old MSG rats is a metabolic alteration characterized by an enhanced adipocyte capacity to transport glucose and to synthetize lipids resulting in increased insulin sensitivity.
Asunto(s)
Animales , Masculino , Ratas , Tejido Adiposo , Glucosa , Insulina , Resistencia a la Insulina/fisiología , Glutamato de Sodio , Adipocitos , Tejido Adiposo , Animales Recién Nacidos , Desoxiglucosa , Epidídimo , Insulina , Ratas WistarRESUMEN
Isolated adipocytes from rats submitted to four weeks of ad libitum feeding (AL) or meal feeding (MF, 2 h/22 h, feeding/fasting, meal time: 8:00-10:00 a.m.) schedules or pre-incubated with or without melatonin (0, 1 nM, 10 nM, 100 nM) for 5 h were submitted to insulin-stimulated [3H]-2-deoxyglucose (0.1 mM, 0.12 microCi) uptake rate measurements and insulin binding assays. Insulin sensitivity was defined as the hormone concentration capable of producing the half-maximal transport rate. Insulin sensitivity varied depending on the previous conditions of the adipocytes. In MF animals, adipose cells were more sensitive (EC50 = 0.175 ng/ml) just at the moment of the expected meal. In AL rats, sensitivity was lower (EC50 = 0.678 ng/ml) at 8:00 a.m. and increased (EC50 = 0.398 ng/ml) at 4:00 p.m. These data clearly implicate the expectation of food and period of the day with the regulation of insulin action. All these modifications in sensitivity occurred without any change in insulin receptor number or affinity. Melatonin, a secretory product of the pineal gland, induced an increase in cell sensitivity to insulin in adipocytes incubated with the highest hormone concentration (100 nM). We conclude that factors related to feeding training and circadian rhythmicity modulate cell sensitivity to insulin.