RESUMO
OBJECTIVES: Galacto-oligosaccharides (GOS) are dietary FODMAPs (fermentable carbohydrates) associated with triggering gastrointestinal symptoms in patients with irritable bowel syndrome (IBS). This randomized, double-blind, placebo-controlled, cross-over trial aimed to assess whether oral α-galactosidase co-ingestion with foods high in GOS and low in other FODMAPs would reduce symptoms. METHODS: Patients meeting the Rome III criteria for IBS who were hydrogen-producers on breath testing were recruited. Participants were treated with full-dose (300 GALU (galactosidic units) α-galactosidase) and half-dose enzyme (150 GALU α-galactosidase), and placebo (glucose) in a random order with ≤14 days washout between arms. Following a 3-day low FODMAP run-in period, participants consumed provided diets high in GOS for a further 3-days. Gastrointestinal symptoms were measured daily using a 100 mm visual-analogue-scale, and breath samples taken hourly on the second last day with hydrogen content analysed as area-under-the-curve. RESULTS: Thirty-one patients with IBS (20 IBS-D, 4 IBS-C, 7 IBS-M) completed the study. The addition of high GOS foods resulted in a significant increase in overall symptoms with 21 patients exhibiting GOS-sensitivity (>10 mm increase for overall symptoms). Of those, full-dose enzyme reduced overall symptoms (median 24. 5(IQR 17.5-35.8) vs. 5.5(1.5-15.0) mm; P=0.006) and bloating (20.5(9.5-42.0) vs. 6.5(2.0-15.8); P=0.017). Breath hydrogen production was minimal with no differences seen between placebo and full-dose (P=0.597). CONCLUSIONS: Oral α-galactosidase taken with high GOS foods provides a clinically significant reduction in symptoms in GOS-sensitive individuals with IBS. This strategy can be translated into practice to improve tolerance to high GOS foods as an adjunct therapy to the low FODMAP diet.
Assuntos
Carboidratos da Dieta/efeitos adversos , Galactose/efeitos adversos , Síndrome do Intestino Irritável/tratamento farmacológico , Oligossacarídeos/efeitos adversos , alfa-Galactosidase/uso terapêutico , Adulto , Testes Respiratórios , Estudos Cross-Over , Progressão da Doença , Método Duplo-Cego , Feminino , Humanos , Síndrome do Intestino Irritável/induzido quimicamente , Síndrome do Intestino Irritável/fisiopatologia , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
A decrease in dopamine D2 receptor (D2R) binding in the striatum is one of the most common findings in disorders that involve a dysregulation of motivation, including obesity, addiction and attention deficit hyperactivity disorder. As disruption of D2R signaling in the ventral striatum--including the nucleus accumbens (NAc)--impairs motivation, we sought to determine whether potentiating postsynaptic D2R-dependent signaling in the NAc would improve motivation. In this study, we used a viral vector strategy to overexpress postsynaptic D2Rs in either the NAc or the dorsal striatum. We investigated the effects of D2R overexpression on instrumental learning, willingness to work, use of reward value representations and modulation of motivation by reward associated cues. Overexpression of postsynaptic D2R in the NAc selectively increased motivation without altering consummatory behavior, the representation of the value of the reinforcer, or the capacity to use reward associated cues in flexible ways. In contrast, D2R overexpression in the dorsal striatum did not alter performance on any of the tasks. Thus, consistent with numerous studies showing that reduced D2R signaling impairs motivated behavior, our data show that postsynaptic D2R overexpression in the NAc specifically increases an animal's willingness to expend effort to obtain a goal. Taken together, these results provide insight into the potential impact of future therapeutic strategies that enhance D2R signaling in the NAc.
Assuntos
Regulação da Expressão Gênica/fisiologia , Motivação/fisiologia , Núcleo Accumbens/metabolismo , Receptores de Dopamina D2/metabolismo , Análise de Variância , Animais , Condicionamento Clássico , Condicionamento Operante , Vetores Genéticos/fisiologia , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/metabolismo , Recompensa , Trítio/metabolismoRESUMO
INTRODUCTION/BACKGROUND: As a proxy for adiposity, body mass index (BMI) provides a practical public health metric to counter obesity-related disease trends. On an individual basis, BMI cannot distinguish fat and lean components of body composition. Further, the relationship between BMI and body composition may be altered in response to physical training. We investigated this dynamic relationship by examining the effect of US Army basic combat training (BCT) on the association between BMI and per cent body fat (%BF). METHODS: BMI and %BF were measured at the beginning (week 1) and end (week 9) of BCT in female (n=504) and male (n=965) trainees. Height and weight were obtained for BMI, and body composition was obtained by dual X-ray absorptiometry. Sensitivity and specificity of BMI-based classification were determined at two BMI thresholds (25 kg/m2 and 27.5 kg/m2). RESULTS: A progressive age-related increase in fat-free mass index (FFMI) was observed, with an inflection point at age 21 years. In soldiers aged 21+, BMI of 25.0 kg/m2 predicted 33% and 29% BF in women and 23% and 20% BF in men and BMI of 27.5 kg/m2 predicted 35% and 31% BF in women and 26% and 22% BF in men, at the start and end of BCT, respectively. Sensitivity and specificity of BMI-based classification of %BF were poor. Soldiers below BMI of 20 kg/m2 had normal instead of markedly reduced %BF, reflecting especially low FFMI. CONCLUSIONS: BCT alters the BMI-%BF relationship, with lower %BF at a given BMI by the end of BCT compared with the beginning, highlighting the unreliability of BMI to try to estimate body composition. The specific BMI threshold of 25.0 kg/m2, defined as 'overweight', is an out-of-date metric for health and performance outcomes. To the extent that %BF reflects physical readiness, these data provide evidence of a fit and capable military force at BMI greater than 25.0 kg/m2.
Assuntos
Militares , Humanos , Masculino , Feminino , Adulto Jovem , Adulto , Índice de Massa Corporal , Tecido Adiposo/fisiologia , Obesidade , Composição Corporal/fisiologiaRESUMO
WHAT IS KNOWN AND OBJECTIVE: Advances in medical technology have made insulin pumps an attractive treatment option for patients with type 1 diabetes and in particular for children and young people. Previous studies have accounted the experiences and views of children/young people and their parents for the use of the injection therapy, but very few have focused on the use of insulin pumps. The objective of this review was to identify studies that explore the experiences of children/young people and their parents on the transition from injections to insulin pump therapy, in the context of their social life. METHODS: A systematic literature search was conducted, and six studies meeting the inclusion and exclusion criteria were identified. RESULTS: Views and perspectives from the studies identified mainly focused on: introduction to the pump; reasons for the transition to pump therapy; advantages and disadvantages of this treatment option; and impact on quality of life (QoL). Parents and/or children reported that they learned about pump therapy either formally from a healthcare professional or informally from a friend or the internet. Many reasons were identified for the transition, the most important being the pursuit of stable and controlled blood sugar levels and the desire for a more flexible lifestyle. Participants highlighted the advantages of insulin pumps in terms of improved diabetes control. Moreover, there was a positive impact on the QoL, as insulin pumps provided children greater flexibility in lifestyles especially with regards to meals and socialization. In contrast, psychosocial issues such as pump visibility and physical restrictions were highlighted as disadvantages. Issues such as day-to-day management were also discussed. WHAT IS NEW AND CONCLUSION: Exploring children/young people's perspectives on the use of pump therapy for managing their diabetes, and parental reflections in caring for those children is important as it provides evidence informing policy for the wider implementation of this technology in the management of diabetes in children. However, the review revealed that there is a scarcity of data in this area and that further research is needed.
Assuntos
Diabetes Mellitus Tipo 1/tratamento farmacológico , Sistemas de Infusão de Insulina/psicologia , Insulina/administração & dosagem , Adolescente , Glicemia/efeitos dos fármacos , Criança , Diabetes Mellitus Tipo 1/psicologia , Humanos , Hipoglicemiantes/administração & dosagem , Estilo de Vida , Pais/psicologia , Qualidade de Vida , Socialização , Adulto JovemRESUMO
Myocardial infarction in humans provokes an acute phase response, and C-reactive protein (CRP), the classical acute phase plasma protein, is deposited together with complement within the infarct. The peak plasma CRP value is strongly associated with postinfarct morbidity and mortality. Human CRP binds to damaged cells and activates complement, but rat CRP does not activate complement. Here we show that injection of human CRP into rats after ligation of the coronary artery reproducibly enhanced infarct size by approximately 40%. In vivo complement depletion, produced by cobra venom factor, completely abrogated this effect. Complement depletion also markedly reduced infarct size, even when initiated up to 2 h after coronary ligation. These observations demonstrate that human CRP and complement activation are major mediators of ischemic myocardial injury and identify them as therapeutic targets in coronary heart disease.
Assuntos
Proteína C-Reativa/metabolismo , Ativação do Complemento , Infarto do Miocárdio/sangue , Doença Aguda , Animais , Proteína C-Reativa/administração & dosagem , Humanos , Infarto do Miocárdio/patologia , Infarto do Miocárdio/fisiopatologia , RatosRESUMO
Zinc, which is essential for many cellular processes, is controlled by zinc transporters and through buffering by metallothioneins and glutathione. Although zinc is increasingly implicated in disease states, little is known about how zinc regulates cellular biochemical pathways. Recent seminal articles have revealed discrete zinc-trafficking pathways that are linked to signalling cascades, particularly those involving protein phosphatase inhibition and downstream activation of mitogen-activated protein kinases and tyrosine kinases. Here, we discuss the mechanisms of cellular zinc homeostasis, and we propose an important role for the zinc transporter solute carrier family 39, member 7 (SLC39A7; commonly referred to as ZIP7). ZIP7 releases zinc from the endoplasmic reticulum and might be required for tyrosine kinase activation. These observations position ZIP7 at a critical node in zinc-mediated tyrosine kinase signalling and suggest that this protein might form a novel target for diseases such as cancer where prevention of tyrosine kinase activation would be therapeutically advantageous.
Assuntos
Proteínas de Transporte de Cátions/metabolismo , Neoplasias/fisiopatologia , Proteínas Tirosina Quinases/metabolismo , Zinco/metabolismo , Proteínas de Transporte de Cátions/análise , Humanos , Neoplasias/tratamento farmacológico , Transdução de SinaisRESUMO
As an alternative to the usual insulin injections, insulin pumps have been introduced as an advanced method of insulin delivery for managing type 1 diabetes mellitus patients. This review documents the history of insulin pump development and the production of 'smart pumps' that offer patients greater dosing accuracy, flexibility, and ease of use. This has resulted in an increase in the number of insulin pump users around the world. This paper also provides a comprehensive survey of the pumps currently available on the market and their specifications. Unique features of each product and the drawbacks are addressed in the review. The future direction of insulin pump development is targeted toward closing the loop, to allow feedback control between an insulin pump and a glucose sensor, and hence finer adjustment of insulin delivery rates as required.
Assuntos
Diabetes Mellitus Tipo 1/tratamento farmacológico , Sistemas de Infusão de Insulina/tendências , Insulina/administração & dosagem , Animais , Glicemia/análise , Glicemia/efeitos dos fármacos , Desenho de Equipamento , Humanos , Hipoglicemiantes/administração & dosagemRESUMO
Acquired resistance to endocrine therapies presents a major obstacle to the successful treatment of breast cancer patients. Previously, we have shown that acquisition of resistance to tamoxifen in breast cancer cells is accompanied by an elevation in Src kinase activity which promotes an aggressive, invasive phenotype in vitro. Here, we have explored the potential therapeutic effects of combining Src inhibition with anti-oestrogen treatment on the development of endocrine insensitivity in breast cancer cells. Treatment of MCF7 and T47D cells with tamoxifen alone resulted in an initial growth inhibitory phase followed by the eventual development of tamoxifen resistance together with an elevation of Src kinase activity, which was central to their increased invasive capacity. Chronic exposure of both cell types to the Src inhibitor, AZD0530, as a monotherapy resulted in outgrowth of AZD0530-resistant cells, in which Src kinase activity remained suppressed as did their in vitro invasive nature. Treatment of both MCF7 and T47D cells with AZD0530 in combination with tamoxifen resulted in a reduction of Src activity together with inhibition of focal adhesion kinase phosphorylation and a complete abrogation of their in vitro invasive behaviour. Furthermore, combination therapy significantly suppressed expression of cyclinD1 and c-myc and prevented cell proliferation and the subsequent emergence of a resistant phenotype, with total cell loss occurring by 12 weeks. These data demonstrate that pharmacological targeting of Src kinase, in conjunction with antihormone therapies, effectively prevents antihormone resistance in breast cancer cells in vitro and suggests a potential novel therapeutic benefit of Src kinase inhibitors clinically.
Assuntos
Antineoplásicos/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Receptor alfa de Estrogênio/metabolismo , Quinases da Família src/metabolismo , Apoptose , Benzodioxóis/farmacologia , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Estrogênios/metabolismo , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Humanos , Invasividade Neoplásica , Fosforilação , Quinazolinas/farmacologia , Resultado do TratamentoRESUMO
Histamine content of rat brain was lowered quickly by inhibitors of histidine decarboxylase, suggesting that a portion of brain histamine turns over rapidly. Restraint and exposure to cold also reduced brain histamine levels and markedly augmented its formation in the hypothalamus.
Assuntos
Encéfalo/metabolismo , Temperatura Baixa , Histamina/metabolismo , Estresse Fisiológico/metabolismo , Animais , Carboxiliases/antagonistas & inibidores , Córtex Cerebral/análise , Cresóis/farmacologia , Histamina/análise , Histidina/metabolismo , Hidrazinas/farmacologia , Hipotálamo/análise , Hipotálamo/metabolismo , Masculino , Bulbo/análise , Mesencéfalo/análise , Ponte/análise , Ratos , Tálamo/análise , TrítioRESUMO
d-Amphetamine is markedly more potent an inhibitor of catecholamine uptake by norepinephrine neurons in the brain than is 1-amphetamine, whereas the two isomers are equally active in inhibiting catecholamine uptake by the dopamine neurons of the corpus striatum. In behavioral studies, d-amphetamine is ten times as potent as 1-amphetamine in enhancing locomotor activity, while it is only twice as potent in eliciting a compulsive gnawing syndrome. This suggests that the locomotor stimulation induced by amphetamine involves central norepinephrine, while dopamine neurons play an important role in the induced compulsive gnawing behavior. Assessment of differential actions of d- and 1-amphetamine may be an efficient method to differentiate behaviors involving norepinephrine or dopamine in the brain.
Assuntos
Anfetamina/farmacologia , Encéfalo/metabolismo , Dextroanfetamina/farmacologia , Dopamina/metabolismo , Norepinefrina/metabolismo , Animais , Gânglios da Base/metabolismo , Encéfalo/efeitos dos fármacos , Tronco Encefálico/metabolismo , Cerebelo/metabolismo , Comportamento Compulsivo/efeitos dos fármacos , Depressão Química , Humanos , Hipotálamo/metabolismo , Mesencéfalo/metabolismo , Atividade Motora/efeitos dos fármacos , Ratos , Estereoisomerismo , Tálamo/metabolismo , TrítioRESUMO
A strain of pigs bearing three immunogenetically defined lipoprotein-associated markers (allotypes), designated Lpb5, Lpr1, and Lpu1, has marked hypercholesterolemia on a low fat, cholesterol-free diet. Unlike individuals with familial hypercholesterolemia or WHHL rabbits, the affected pigs have normal low density lipoprotein receptor activity. The animals, by 7 months of age, have extensive atherosclerotic lesions in all three coronary arteries. This strain of pig represents an animal model for atherosclerosis and hypercholesterolemia associated with mutations affecting the structures of plasma lipoproteins. One of the variant apolipoproteins, Lpb5, is apolipoprotein-B. A second variant apolipoprotein (Lpr1), termed apo-R, is a 23-kilodalton protein present in both the very low density (d less than 1.006 g/ml) and the very high density (d greater than 1.21 g/ml) fractions of pig plasma. Isoforms of this protein correlate with two Lpr alleles, Lpr1 and Lpr2. The Lpr genes segregate independently of the Lpb5 and Lpu1 alleles. The Lpu1 allotype is a component of low density lipoprotein and is genetically linked to Lpb5.
Assuntos
Arteriosclerose/genética , Modelos Animais de Doenças , Hipercolesterolemia/genética , Lipoproteínas/genética , Alelos , Animais , Apolipoproteínas B/genética , Arteriosclerose/sangue , Colesterol/sangue , Feminino , Genótipo , Hipercolesterolemia/sangue , Testes Imunológicos , Lipoproteínas/sangue , Lipoproteínas LDL/sangue , Lipoproteínas LDL/genética , Lipoproteínas VLDL/sangue , Lipoproteínas VLDL/genética , Masculino , Mutação , Receptores de LDL/metabolismo , SuínosRESUMO
The concentration of histamine in the brains of neonatal rats is considerably higher than that in adults. Subcellular fractionation studies revealed that about 90 percent of the histamine content of neonatal rat brain is confined to the crude nuclear fraction obtained by differential fractionation. Purified nuclei prepared from these fractions retained 90 percent of their histamine content. The nuclear localization of histamine in the brains of neonatal rats suggests a function for histamine in modulating the growth processes of the neonatal brain.
Assuntos
Animais Recém-Nascidos/fisiologia , Diencéfalo , Histamina , Fatores Etários , Animais , Química Encefálica , DNA/isolamento & purificação , Diencéfalo/análise , Diencéfalo/crescimento & desenvolvimento , Histamina/isolamento & purificação , Histamina/fisiologia , Histocitoquímica , RatosRESUMO
AIM: To compare the quality of colonoscopy in the Kent and Medway Strategic Health Authority with national standards and previous audits. METHOD: A prospective 12-month audit of colonoscopy quality as assessed by number of procedures performed, total colonoscopy rates, sedation usage, and complications. Data were collected by 7 endoscopy units on 5905 colonoscopies performed by 62 colonoscopists. The endoscopy unit nurses, as opposed to the colonoscopists, verified that colonoscopy was total. RESULTS: Seven doctors stopped performing colonoscopy during the study period. Thirty-nine of 55 colonoscopists (71 %) achieved total colonoscopy in at least 90 % of cases; 12 (22 %) completed colonoscopy in 80 - 89 % of their cases and 4 (7 %) in 79 % or less of their cases. Seventy-nine percent of colonoscopists used sedation in accordance with British Society of Gastroenterology (BSG) guidelines. Only 22 of 55 (40 %) of colonoscopists performed more than 100 colonoscopies during the 12-month audit period. Reported complications were below expected levels. CONCLUSION: In our study almost one-third of colonoscopists did not achieve colonoscopy completion rates of at least 90%, and less than half performed more than 100 colonoscopies during the 12 month study. Adherence to quality standards appears to be inadequate.
Assuntos
Colonoscopia/normas , Auditoria Médica , Garantia da Qualidade dos Cuidados de Saúde , Colonoscopia/efeitos adversos , Feminino , Humanos , Masculino , Estudos Prospectivos , Reino UnidoRESUMO
BACKGROUND AND OBJECTIVE: Access to medicines by young people with chronic conditions during the school day and suitable environments and support in the administration of a range of dosage forms may be required for optimal clinical management. Whilst Government policy emphasizes that children and young people with chronic illness should be able to lead as normal lives as possible, there is only limited evidence on the experiences and concerns of young people and their parents regarding the use of medicines at school and the impact on school life. The objective of this study was to examine the experiences and concerns of young people with chronic conditions, and their parents/carers, in managing medication at school. METHODS: Data were gathered in audio-recorded face-to-face semi-structured interviews with 27 young people (5-18 years) and their parents attending out-patient clinics at a major London teaching hospital. Open-ended questions provided an opportunity for participants to describe experiences and views in the context of their activities, priorities and concerns and enabled a qualitative analysis. RESULTS AND DISCUSSION: The findings indicated that storage and access of medicines did not present major problems for young people receiving regular medication. However, those receiving medication on a 'when required' basis reported barriers to access. The most common concern regarding taking medication was lack of privacy, which sometimes led to non-adherence. Adverse effects of medication were highlighted as a cause of both non-adherence and poorer school performance. Extracurricular activities such as school trips were not viewed as presenting a problem by those who were interviewed. However, this was often because young people and their families devised their own strategies regarding the use of medicines that did not depend on the input of staff. There was wide variation in responses about the support young people received from school staff, with evidence of helpful and unhelpful practice. The potential benefits of liaison between schools and health professionals to assist schools in their support of students with their medicines were highlighted. CONCLUSION: This study has identified medication-related issues from the perspective of young people and their parents, indicating ways in which their needs might be served more sensitively and effectively.
Assuntos
Atitude Frente a Saúde , Pais/psicologia , Instituições Acadêmicas , Estudantes/psicologia , Logro , Adolescente , Criança , Doença Crônica , Coleta de Dados , Armazenamento de Medicamentos/métodos , Docentes/normas , Feminino , Humanos , Londres/epidemiologia , Masculino , Adesão à Medicação/psicologia , Privacidade/psicologia , Adulto JovemRESUMO
Neural cell adhesion molecule (N-CAM) has been implicated in cellular interactions involved in cardiac morphogenesis and innervation. Immunohistochemical techniques and Western blot analysis were used to determine the localization and isoforms of N-CAM in the developing and extrinsically denervated human heart. Myocardial and conducting cells in the fetal heart (7-24 wk gestation) exhibited sarcolemmal immunoreactivity, the major desialo N-CAM isoforms being 150, 145, 120, 115, and 110 kD. N-CAM expression appeared to be downregulated in the myocardium during adult life, with relatively little sarcolemmal immunoreactivity being detected in normal donor tissues. In contrast to the temporal changes observed in the myocardium, both the developing and mature cardiac innervation displayed N-CAM immunofluorescence staining, localized to neuronal cell bodies, nerve fascicles and fibres. Extrinsically denervated cardiac allografts, obtained 2 d to 91 mo after transplantation, showed extensive sarcolemmal and intercalated disc immunostaining and expression of 125-, 120-, and 115-kD isoforms. Tissues from explanted recipient hearts and atrial appendage samples obtained during coronary bypass graft operations were also examined and displayed varying amounts of N-CAM immunoreactivity. We conclude that the expression of N-CAM immunoreactivity and isoforms in the human heart is developmentally regulated and may be modulated by factors such as cardiac innervation and myocardial hypertrophy.
Assuntos
Moléculas de Adesão Celular Neuronais/análise , Coração Fetal/química , Transplante de Coração , Miocárdio/química , Adulto , Moléculas de Adesão Celular Neuronais/imunologia , Criança , Feminino , Coração/inervação , Humanos , Immunoblotting , Imuno-Histoquímica , Gravidez , Transplante HomólogoRESUMO
The aerosol properties of liposomes and their physical stability to aerosolization were evaluated using an air-jet nebulizer (Pari LC Plus) and a customized large aperture vibrating-mesh nebulizer (Aeroneb Pro-8microm). Soya phosphatidylcholine: cholesterol (1:1 mole ratio) multilamellar liposomes (MLVs) entrapping salbutamol sulfate were nebulized directly, or after being reduced in size by extrusion through 1 or 0.4microm polycarbonate membrane filters. MLVs were very unstable to jet nebulization and stability was not markedly enhanced when vesicles were extruded before nebulization, such that drug losses from delivered liposomes using the Pari nebulizer were up to 88% (i.e. only 12% retained in liposomes). The Aeroneb Pro-8microm nebulizer was less disruptive to liposomes, completed nebulization in a much shorter time, and produced greater mass output rate than the Pari nebulizer. However, aerosol droplets were larger, total drug and mass outputs were lower and aerosolization performance was dependent on formulation. Vibrating-mesh nebulization was less disruptive to liposomes extruded through the 1microm membranes compared with the non-extruded MLVs, so that the retained entrapment of the drug in the nebulized vesicles was 56% and 37%, respectively. However, extrusion of liposomes to 0.4microm resulted in reduced stability of liposomes to vibrating-mesh nebulization (retained entrapment=41%) which was attributed to the reduced liposome lamellarity and subsequent reduced resistance to nebulization-induced shearing. This study has shown that vibrating-mesh nebulization using the customized large aperture mesh nebulizer (Aeroneb Pro-8microm) had a less disruptive effect on liposomes and produced a higher output rate compared with the Pari LC Plus air-jet nebulizer. On the other hand, the air-jet nebulizer produced higher total mass and drug outputs and smaller aerosol droplets.
Assuntos
Albuterol/química , Broncodilatadores/química , Lipossomos/química , Nebulizadores e Vaporizadores , Tamanho da Partícula , Administração por Inalação , Aerossóis/química , Química Farmacêutica , Colesterol/química , Cromatografia Líquida de Alta Pressão , Sistemas de Liberação de Medicamentos , Estabilidade de Medicamentos , Filtração , Lasers , Membranas Artificiais , Microscopia Eletrônica de Transmissão , Fosfatidilcolinas/química , Cimento de Policarboxilato , Glycine max/químicaRESUMO
Zinc is an essential trace element participating in diverse biological processes. Cellular zinc levels are strictly controlled by two families of transport proteins: ZIP channels (SLC39A) and ZnT transporters (SLC30A). ZIP channels increase cytosolic zinc levels by importing zinc into cells or releasing zinc from intracellular stores such as the ER. Among all the 14 human members of the ZIP family, ZIP7 is a gatekeeper of zinc release from intracellular stores, requiring post-translational activation by phosphorylation on residues S275 and S276, resulting in activation of multiple downstream pathways. Employing site-directed mutagenesis, we investigated the importance of these individual serine residues as well as other predicted phosphorylation sites on ZIP7, showing that all four sites are required for maximal ZIP7 activation. Using phosphor-protein arrays, we also discovered the major signalling pathways that were activated as a direct result of ZIP7-mediated zinc release from intracellular stores. These data reveal the role of ZIP7-mediated zinc release from intracellular stores in driving major pathways, such as MAPK, mTOR and PI3K-AKT, involved in providing cell survival and proliferation and often over activated in cancer.
Assuntos
Proteínas de Transporte de Cátions/metabolismo , Proliferação de Células , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Humanos , Células MCF-7 , Neoplasias/metabolismo , Fosforilação , Zinco/metabolismoRESUMO
The recently described hemoglobin scavenger receptor CD163 mediates the endocytosis of hemoglobin:haptoglobin (Hb:Hp) complexes and thereby counters Hb-induced oxidative tissue damage after hemolysis. Although CD163 has been indirectly associated with antiinflammatory and atheroprotective activity, no ligand-receptor-effector pathway has yet been described for this receptor. To understand the significance of CD163 and more clearly define downstream pathways linked to inflammatory resolution, we studied the expression and function of CD163 in human monocytes/macrophages using both in vitro and in vivo models. Differentiation of human blood monocytes into macrophages either by in vitro culture or in resolving cantharidin-induced skin blisters led to an equivalent increase (>15x) in CD163 expression. Elevated CD163 levels were also noted on circulating monocytes in cardiac surgical patients during the resolution phase of the systemic inflammatory response to cardiopulmonary bypass surgery. In each case, binding of Hb:Hp to CD163-bearing cells elicited potent interleukin-10 secretion, and this was inhibited by the anti-CD163 antibody RM3/1. Release of interleukin-10, in turn, induced heme oxygenase-1 stress protein synthesis via an autocrine mechanism. Such induction of heme oxygenase-1 was observed in vivo 24 to 48 hours after the onset of cardiopulmonary bypass surgery. These results identify novel antiinflammatory and cytoprotective effector pathways in human monocytes/macrophages related to Hb scavenging and metabolism, which may have relevance in atheroprotection, wound healing, and patient recovery postoperatively.
Assuntos
Antígenos CD/fisiologia , Antígenos de Diferenciação Mielomonocítica/fisiologia , Ponte Cardiopulmonar , Heme Oxigenase (Desciclizante)/biossíntese , Interleucina-10/biossíntese , Macrófagos/imunologia , Monócitos/imunologia , Receptores de Superfície Celular/fisiologia , Idoso , Antígenos CD/metabolismo , Antígenos de Diferenciação Mielomonocítica/metabolismo , Comunicação Autócrina , Vesícula/imunologia , Células Cultivadas , Ponte de Artéria Coronária , Feminino , Haptoglobinas/metabolismo , Heme Oxigenase-1 , Hemoglobinas/metabolismo , Humanos , Inflamação/enzimologia , Inflamação/metabolismo , Macrófagos/enzimologia , Masculino , Proteínas de Membrana , Pessoa de Meia-Idade , Monócitos/enzimologia , Receptores de Superfície Celular/metabolismoRESUMO
High sensitivity differential scanning calorimetry (HSDSC) has been used to study the interaction of the model proteins lactate dehydrogenase (LDH) and tyrosinase with dimyristoylphosphatidylcholine (DMPC) liposomes, and relate this to the thermal and physical stability of the proteins. On heating, both LDH and tyrosinase denatured irreversibly in a time-dependent manner and modified the phase transition behaviour of DMPC liposomes at all concentrations investigated. The most marked effects occurred for the pretransition rather than the main phospholipid phase transition. The effects on the bilayer are likely to result from electrostatic interactions of the hydrophilic proteins with the head-groups of DMPC molecules, whilst due to their hydrophilic nature they do not penetrate into the bilayer. Tyrosinase is more highly ionised than LDH at the pH of the investigation, which may explain why tyrosinase has a greater effect than LDH on the HSDSC scans at mg/ml protein concentrations.
Assuntos
L-Lactato Desidrogenase/química , Lipossomos/química , Monofenol Mono-Oxigenase/química , Varredura Diferencial de Calorimetria , TemperaturaRESUMO
Using high sensitivity differential scanning calorimetry (HSDSC), the phase transitions of dimyristoylphosphatidylcholine (DMPC) liposomal bilayers and their interaction with the model steroid beclomethasone dipropionate (BDP) were found to be dependent on the method of liposome manufacture. Ethanol-based proliposomes produced liposomes having no phospholipid pretransition, a main transition of high enthalpy and a low onset temperature, and a very low incorporation of the steroid (maximum 1 mol%). This was attributed to an alcohol-induced interdigitation of the bilayers, which was not apparently reversed by flushing the liposome dispersion with nitrogen in an attempt to remove ethanol. For liposomes manufactured by thin film or particulate-based proliposome methods, 1-2.5 mol% steroid was optimal for incorporation within bilayers, although the nature of the steroid interaction with the bilayers differed between the two methods. For liposomes manufactured by the thin film method, a higher steroid concentration resulted in a broadened main transition and a reduced melting cooperativity. This suggests that BDP formed separate domains within the bilayers which caused non-ideal mixing and phase separation at 5 mol% steroid. This observation was absent for liposomes generated from particulate-based proliposomes, indicating separate steroid domains were not formed and subsequent non-ideal mixing and phase separation did not occur. In addition, liposomes generated from particulate-based proliposomes showed reduced pretransition and main transition enthalpies. These differences were attributed to the employment of sucrose to manufacture the particulate-based proliposomes. This study has shown that the thermal behaviour of liposomes and their interaction with beclomethasone dipropionate were dependent on the method of liposome manufacture. Moreover, particulate-based proliposomes may provide a reasonable alternative to the conventional thin film method in producing liposomes incorporating this steroid.