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PURPOSE: The use of thyroid hormones (TH) to treat obesity is unsupported by evidence as reflected in international guidelines. We explored views about this practice, and associations with respondent characteristics among European thyroid specialists. METHODS: Specialists from 28 countries were invited to a survey via professional organisations. The relevant question was whether "Thyroid hormones may be indicated in biochemically euthyroid patients with obesity resistant to lifestyle interventions". RESULTS: Of 17,232 invitations 5695 responses were received (33% valid response rate; 65% women; 90% endocrinologists). Of these, 290 (5.1%) stated that TH may be indicated as treatment for obesity in euthyroid patients. This view was commoner among non-endocrinologists (8.7% vs. 4.7%, p < 0.01), private practice (6.5% vs. 4.5%, p < 0.01), and varied geographically (Eastern Europe, 7.3%; Southern Europe, 4.8%; Western Europe, 2.7%; and Northern Europe, 2.5%). Respondents from Northern and Western Europe were less likely to use TH than those from Eastern Europe (p < 0.01). Gross national income (GNI) correlated inversely with this view (OR 0.97, CI: 0.96-0.97; p < 0.001). Having national guidelines on hypothyroidism correlated negatively with treating obesity with TH (OR 0.71, CI: 0.55-0.91). CONCLUSIONS: Despite the lack of evidence, and contrary to guidelines' recommendations, about 5% of respondents stated that TH may be indicated as a treatment for obesity in euthyroid patients resistant to life-style interventions. This opinion was associated with (i) respondent characteristics: being non-endocrinologist, working in private practice, treating a small number of hypothyroid patients annually and (ii) national characteristics: prevalence of obesity, Eastern Europe, low GNI and lack of national hypothyroidism guidelines.
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In a measurement of isomeric yield-ratios in fission, the Phase-Imaging Ion-Cyclotron-Resonance technique, which projects the radial motions of ions in the Penning trap (JYFLTRAP) onto a position-sensitive micro-channel plate detector, has been applied. To obtain the yield ratio, that is the relative population of two states of an isomer pair, a novel analysis procedure has been developed to determine the number of detected ions in each state, as well as corrections for the detector efficiency and decay losses. In order to determine the population of the states in cases where their mass difference is too small to reach full separation, a Bayesian Gaussian Mixture model was implemented. The position-dependent efficiency of the micro-channel plate detector was calibrated by mapping it with 133Cs+ ions, and a Gaussian Process was trained with the position data to construct an efficiency function that could be used to correct the recorded distributions. The obtained numbers of counts of excited and ground-state ions were used to derive the isomeric yield ratio, taking into account decay losses as well as feeding from precursors.
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INTRODUCTION: Migraine, especially with aura, is a risk factor for ischemic stroke. In this study, we investigated descriptive data and prevalence of migraine in an in-patient stroke population. MATERIALS AND METHODS: Patients with acute cerebrovascular disease (CVD) admitted to the stroke unit during a 6-month period were recruited. Prevalence of migraine was assessed using a structured questionnaire. Additional clinical data regarding risk factors for CVD were evaluated for all responding patients. RESULTS: A total of 229 patients received a questionnaire and 175 answers were collected (response frequency of 76.4%). Responders matched the initial cohort regarding distribution of age, sex, and type of stroke. Thirty-six cases (20.6%) fulfilled the criteria for migraine or probable migraine according to the 2nd edition of the International Headache Classification (ICHD-2). Sixty percent of migraine patients had migraine with aura. Stroke patients with migraine were younger (P = 0.007), the presence of patent foramen ovale (PFO) was significantly increased (P = 0.008), and atrial fibrillation was less common (P = 0.048). There were no other differences between patients with and without migraine headache regarding conventional risk factors. CONCLUSIONS: The prevalence of migraine in this hospital-based stroke cohort was comparable to the estimated prevalence of migraine usually described in population studies. In our study population, the prevalence of migraine with aura was higher than expected. The increased prevalence of PFO in patients with migraine headache corresponds well to previous population studies.
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Trastornos Migrañosos/complicaciones , Trastornos Migrañosos/epidemiología , Accidente Cerebrovascular/complicaciones , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Pacientes Internos/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Prevalencia , Factores de Riesgo , Encuestas y CuestionariosRESUMEN
Heat transport across interfaces is often discussed in terms of the transmission probability of the heat-carrying phonons through the contact zone. Although interface roughness influences the true contact area and affects phonon scattering within the contact zone, its effect on nanoscale heat transport remains poorly understood. Here, we report experimental data on the pressure dependence of thermal transport across polished nanoscale contacts. The data can be quantitatively explained by a model of thermal conductance across interfaces that incorporates the effect of nanoscale roughness through the quantized thermal conductance across individual atomic-scale contacts within the contact zone.
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We report on the first observation of the unbound proton-rich nucleus 15Ne. Its ground state and first excited state were populated in two-neutron knockout reactions from a beam of 500 MeV/u 17Ne. The 15Ne ground state is found to be unbound by 2.522(66) MeV. The decay proceeds directly to 13O with simultaneous two-proton emission. No evidence for sequential decay via the energetically allowed 2- and 1- states in 14F is observed. The 15Ne ground state is shown to have a strong configuration with two protons in the (sd) shell around 13O with a 63(5)% (1s1/2)2 component.
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INTRODUCTION: Migraine, especially migraine with aura, has been described to be associated with an increased risk for ischemic stroke. An increased incidence of silent lesions in the posterior circulation has also been described. METHOD: Six cases with migraine and stroke in close relation over time were retrospectively reviewed. RESULTS: All patients had previously known MA or MO and suffered from a stroke within the first 24-hour period after an acute migraine attack. None of the patients fulfilled the IHS criteria for migrainous infarction. Four out of these six patients had a patent foramen ovale (PFO) or an atrial septal defect (ASD). DISCUSSION: None of these cases can be categorized as migrainous infarctions according to IHS. However, the migraine attack might have been involved in the mechanisms for the development of the infarctions.
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Trastornos Migrañosos/complicaciones , Accidente Cerebrovascular/etiología , Adulto , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
A measurement of the final state distribution of the (8)B ß decay, obtained by implanting a (8)B beam in a double-sided silicon strip detector, is reported here. The present spectrum is consistent with a recent independent precise measurement performed by our collaboration at the IGISOL facility, Jyväskylä [O. S. Kirsebom et al., Phys. Rev. C 83, 065802 (2011)]. It shows discrepancies with previously measured spectra, leading to differences in the derived neutrino spectrum. Thanks to a low detection threshold, the neutrino spectrum is for the first time directly extracted from the measured final state distribution, thus avoiding the uncertainties related to the extrapolation of R-matrix fits. Combined with the IGISOL data, this leads to an improvement of the overall errors and the extension of the neutrino spectrum at high energy. The new unperturbed neutrino spectrum represents a benchmark for future measurements of the solar neutrino flux as a function of energy.
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We report direct force measurements of the formation of a chemical bond. The experiments were performed using a low-temperature atomic force microscope, a silicon tip, and a silicon (111) 7x7 surface. The measured site-dependent attractive short-range force, which attains a maximum value of 2.1 nanonewtons, is in good agreement with first-principles calculations of an incipient covalent bond in an analogous model system. The resolution was sufficient to distinguish differences in the interaction potential between inequivalent adatoms, demonstrating the ability of atomic force microscopy to provide quantitative, atomic-scale information on surface chemical reactivity.
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BACKGROUND: Smoking is a strong risk factor for the development of Graves' ophthalmopathy (GO). Immediate early genes (IEGs) are overexpressed in patients with active GO compared to healthy controls. The aim of this study was to study the effects of tobacco smoking and simvastatin on preadipocytes and orbital fibroblasts (OFs) in the adipogenic process. METHODS: Cigarette smoke extract (CSE) was generated by a validated pump system. Mouse 3T3-L1 preadipocytes or OFs were exposed to 10% CSE with or without simvastatin. Gene expression was studied in preadipocytes and OFs exposed to CSE with or without simvastatin and compared to unexposed cells or cells treated with a differentiation cocktail. RESULTS: In 3T3-L1 preadipocytes, Cyr61, Ptgs2, Egr1 and Zfp36 expression levels were two-fold higher in cells exposed to CSE than in unexposed cells. Simvastatin downregulated the expression of these genes (1.6-fold, 5.5-fold, 3.3-fold, 1.4-fold, respectively). CSE alone could not stimulate preadipocytes to differentiate. Scd1, Ppar-γ and adipogenesis were downregulated in simvastatin-treated preadipocytes compared to nontreated preadipocytes 18-, 35- and 1.7-fold, respectively. In OFs, similar effects of CSE were seen on the expression of CYR61 (1.4-fold) and PTGS2 (3-fold). Simvastatin downregulated adipogenesis, PPAR-γ (2-fold) and SCD (27-fold) expression in OFs. CONCLUSION: CSE upregulated early adipogenic genes in both mouse 3T3-L1 preadipocytes and human OFs but did not by itself induce adipogenesis. Simvastatin inhibited the expression of both early and late adipogenic genes and adipogenesis in preadipocytes and human OFs. The effect of simvastatin should be investigated in a clinical trial of patients with GO.
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Tumor necrosis factor (TNF) is a pleiotropic mediator of inflammatory responses. A cysteine-rich, highly glycosylated 30-kD TNF-binding protein (TNF-BP) purified from urine may have a role in regulation because it protects in vitro against the biological effects of TNF. The cytotoxic effect of TNF on the fibrosarcoma cell line WEHI 164 was inhibited by 50% at a 10-fold excess of TNF-BP. The binding of TNF to the receptor was partially reversed after the addition of TNF-BP. Results from biosynthetic labeling of cells with 35S-cysteine followed by immunoprecipitation with anti-TNF-BP indicated that TNF-BP is formed and released at the cell surface by cleavage because no corresponding cellular polypeptide was observed. A cellular 60-kD polypeptide, which was immunoprecipitated with anti-TNF-BP, may correspond to the transmembrane TNF-receptor molecule and be the precursor of TNF-BP. Thus, TNF-BP appears to be a soluble form of a transmembrane TNF-receptor. Moreover our results demonstrate that the production of TNF-BP is increased when the TNF receptor is downregulated in cells by treatment with TNF or by activation of protein kinase C with phorbol esters. TNF-BP may be an important agent that blocks harmful effects of TNF, and, therefore, useful in clinical applications.
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Receptores de Superficie Celular/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Supervivencia Celular/efectos de los fármacos , Cromatografía en Gel , Regulación hacia Abajo , Fibrosarcoma , Humanos , Concentración de Iones de Hidrógeno , Pruebas de Precipitina , Receptores de Superficie Celular/biosíntesis , Receptores del Factor de Necrosis Tumoral , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacología , Solubilidad , Células Tumorales Cultivadas , Factor de Necrosis Tumoral alfa/farmacologíaRESUMEN
Tumor necrosis factor (TNF), a protein released by activated macrophages, is a central mediator of the host response to infection and inflammation. The TNF-binding protein I (TNF-BP-I) is a soluble fragment of the p60 transmembrane TNF receptor and an antagonist to TNF. The level of serum TNF-BP-I was found to be increased in patients with renal insufficiency as a result of a decrease in the glomerular filtration rate. During hemodialysis of patients with renal failure there was a rapid but transient increase in serum TNF-BP-I. This increase was found to be caused by heparin given before dialysis and a similar dose-dependent response to heparin was observed also in healthy individuals. The finding of a repeated release of TNF-BP-I into the circulation with intermittent injections of heparin indicates that TNF-BP-I is present both in a storage pool and in a circulating pool. The mechanism for the heparin-mediated release of TNF-BP-I was not explained; TNF-BP did not show affinity for heparin. On the other hand, TNF was found to have affinity for heparin and it could also be dissociated from heparin by TNF-BP-I. It is suggested that heparin-like molecules of the extracellular matrix can retain TNF in physical proximity with target cells and restrict the actions of TNF and protect against systemic harmful manifestations.
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Proteínas Portadoras/metabolismo , Heparina/metabolismo , Receptores del Factor de Necrosis Tumoral , Factor de Necrosis Tumoral alfa/metabolismo , Heparina/farmacología , Humanos , Enfermedades Renales/metabolismo , Receptores Tipo I de Factores de Necrosis Tumoral , Diálisis Renal , Receptores Señuelo del Factor de Necrosis TumoralRESUMEN
Sustained release or high levels of interleukin-1 (IL-1) and/or tumor necrosis factor (TNF), as observed after endotoxin challenge, can produce a variety of toxicities. Naturally occurring inhibitors to IL-1 and TNF, IL-1 receptor antagonist (IL-1ra) and soluble TNF receptor forms, have been detected. These proteins may function to buffer or limit the effects of these cytokines as part of a regulatory network. As part of a clinical trial of recombinant human interleukin-1 beta (rhIL-1 beta), serial plasma samples were obtained from 6 patients with metastatic melanoma treated with 30-min infusions of rhIL-1 beta for 5 consecutive days. The presence of circulating IL-1 receptor antagonist and soluble TNF binding proteins (TNF-R55-BP and TNF-R75-BP) were assessed. A maximum 86-fold increase for IL-1ra, a 7-8-fold increase for TNF-R55-BP, and a 2-3-fold increase for TNF-R75-BP were seen 2-4 h, 1 h, and 4 h, respectively, after rhIL-1 beta infusion. On each day of the treatment, the secretion of IL-1ra and release of TNF-R55-BP was observed, but there was no accumulation above baseline value for IL-1ra before each of the 5 daily infusions. Although there was a steady decrease of the 6-h postinfusion plasma levels for IL-1ra and TNF-R55-BP over the 5 treatment days, no increase of clinical side effects was noted. Two patients had measurable levels of TNF-alpha, but no correlation to TNF-binding proteins was observed. Our data show that early after rhIL-1 beta infusion the induction of IL-1ra secretion, as well as TNF-binding protein release, is observed.
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Interleucina-1/farmacología , Melanoma/sangre , Receptores de Superficie Celular/análisis , Sialoglicoproteínas/sangre , Adulto , Anciano , Femenino , Humanos , Proteína Antagonista del Receptor de Interleucina 1 , Interleucina-1/administración & dosificación , Interleucina-1/efectos adversos , Masculino , Melanoma/terapia , Persona de Mediana Edad , Receptores del Factor de Necrosis Tumoral , Factores de TiempoRESUMEN
BACKGROUND: Deficits in somatostatin-like immunoreactivity (SLI) and corticotropin-releasing factor immunoreactivity (CRF-IR) are well recognized as prominent neurochemical deficits in Alzheimer disease (AD). The question of whether these profound neuropeptidergic deficits found in patients with end-stage disease extend into those with much earlier disease is relatively unanswered. To determine the relation between level of SLI and CRF-IR in different cerebrocortical regions to the earliest signs of cognitive deterioration in AD. METHODS: We examined SLI and CRF-IR levels in 9 neocortical brain regions of 66 elderly patients in a postmortem study of nursing home residents who had either no significant neuropathologic lesions or lesions associated only with AD. Patients were assessed by the Clinical Dementia Rating scale (CDR) to have no dementia or questionable, mild, or moderate dementia, and were compared with 15 patients with severe dementia. RESULTS: Both CRF-IR and SLI were significantly reduced in the cortices of patients with the most severe dementia, but only the levels of CRF-IR were reduced in those with mild (CDR = 1.0) and moderate dementia (CDR = 2.0). Levels of CRF-IR and SLI correlated significantly with CDR, but this correlation was more robust for CRF-IR and persisted even when severely cognitively impaired patients were eliminated from analysis. CONCLUSIONS: Although SLI and CRF-IR levels are significantly reduced in patients with severe dementia, only CRF-IR is reduced significantly in the cortices of those with mild dementia. Thus, CRF-IR can serve as a potential neurochemical marker of early dementia and possibly early AD.
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Enfermedad de Alzheimer/fisiopatología , Hormona Liberadora de Corticotropina/análisis , Neocórtex/química , Neuropéptidos/análisis , Péptidos/análisis , Somatostatina/análisis , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/diagnóstico , Biomarcadores , Hormona Liberadora de Corticotropina/fisiología , Corteza Entorrinal/química , Lóbulo Frontal/química , Humanos , Inmunohistoquímica , Persona de Mediana Edad , Neuropéptidos/fisiología , Péptidos/fisiología , Escalas de Valoración Psiquiátrica/estadística & datos numéricos , Índice de Severidad de la Enfermedad , Somatostatina/fisiología , Lóbulo Temporal/químicaRESUMEN
Mitogen-stimulated lymphocytes and some T-lymphocyte lines released a polypeptide called differentiation-inducing factor (DIF), which restored maturation of promyelocytic HL-60 cells and inhibited growth of leukemic and normal progenitor cells. Tumor Necrosis Factor (TNF), which has been found to be not identical with DIF, displayed similar effects. On the other hand, an antigenic relationship was shown between DIF and lymphotoxin (LT) by use of neutralizing antibodies. An activity, which cochromatographed with DIF during all purification steps, competed with binding of both rLT and rTNF to HL-60 cells. Approximately 2,000 binding sites for rLT were detected per cell, with a Kd of 330 pmol/l. Our observations are indications of a functional and an antigenic connection between DIF and LT, and indicate that TNF, LT and DIF share cell surface-binding sites. These binding sites are down regulated by activation of protein kinase-C. Results from modulation of the response indicated that the signal for differentiation might be transduced through activation of phospholipase A2. In order to understand myeloid differentiation and the effects of differentiation factors, we have pursued investigations of the biosynthesis and processing of one marker of myeloid differentiation, namely myeloperoxidase (MPO). Our results disclosed that MPO was synthesized as a larger precursor of Mr 90,000 to which a heme group was added, followed by proteolytic cleavage in pregranular structures to generate mature heavy Mr 60,000 and light Mr 12,000 subunits. Processing of MPO was independent of acidification. cDNA probes are now available for MPO, so that investigation of gene expression in relation to differentiation and induction of differentiation is facilitated.
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Diferenciación Celular/efectos de los fármacos , Leucemia Mieloide Aguda/patología , Leucocitos Mononucleares/metabolismo , Linfocinas/metabolismo , Humanos , Leucemia Promielocítica Aguda/patología , Linfocinas/farmacología , Linfotoxina-alfa/farmacología , Proteínas de Neoplasias/biosíntesis , Peroxidasa/biosíntesis , Procesamiento Proteico-Postraduccional , Proteínas Recombinantes/farmacología , Células Tumorales Cultivadas/efectos de los fármacos , Factor de Necrosis Tumoral alfa/farmacologíaRESUMEN
Tumor necrosis factor-alpha (TNF-alpha) has recently been implicated as a regulator growth and differentiation of normal and malignant B cells. We utilized a selected clone (I-83) of primary resting B-type chronic lymphocytic leukemia (B-CLL) cells, inducible to activation, growth and differentiation in vitro, as a model system to study the possible role of TNF-alpha as an autocrine growth factor for such cells. Our results show that unstimulated I-83 B-CLL cells produced a low level of TNF-alpha mRNA, as shown by Northern blot analysis, and cytoplasmic TNF-alpha, determined in individual cells by immunocytochemistry. Secreted TNF-alpha could, however, not be detected in the medium by ELISA. TNF-alpha synthesis and secretion was, however, induced to high levels by stimulation of the B-CLL cells with interleukin-2 (IL-2) after activation by 12-O-tetradecanoylphorbol-13-acetate (TPA) or Staphylococcus aureus Cowan strain I (SAC) and B-cell stimulatory factor-MP6 (thioredoxin). A moderate increase in TNF-alpha secretion was also induced by TPA or IL-2 alone. IL-4 did not have any major effects on the production of TNF-alpha in activated cells, but inhibited the IL-2-induced production of TNF-alpha in SAC-activated cells. The cell surface expression of TNF-alpha receptors (TNF-R), as determined by binding assay using 125I-labelled recombinant TNF-alpha (rTNF-alpha), was also induced after SAC or TPA activation, but shed receptors (TNF-binding proteins) were only observed after TPA activation. Exogenously added rTNF-alpha in combination with TPA or SAC induced a high level of DNA synthesis in I-83 B-CLL cells. The increased endogenous production and secretion of TNF-alpha during induced growth stimulation, the induced expression of TNF-R, and the mitogenic effect of TNF-alpha on activated B-CLL cells raise the question whether TNF-alpha may function as an autocrine co-stimulator of B-CLL cell growth as recently suggested. anti-TNF-alpha and anti-TNF-R antibodies, however, failed to inhibit the IL-2- and IL-4-induced proliferation of activated I-83 B-CLL cells.
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Interleucina-2/farmacología , Leucemia Linfocítica Crónica de Células B/metabolismo , ARN Mensajero/biosíntesis , Receptores de Superficie Celular/metabolismo , Factor de Necrosis Tumoral alfa/biosíntesis , ADN de Neoplasias/biosíntesis , Humanos , Interleucina-4/farmacología , Receptores del Factor de Necrosis Tumoral , Staphylococcus aureus , Acetato de Tetradecanoilforbol/farmacología , Tiorredoxinas/farmacología , Factor de Necrosis Tumoral alfa/genéticaRESUMEN
Production and release of lymphotoxin (LT) was studied by metabolic labeling of human B- and T-cell lines with 14C-leucine and 35S-methionine. LT was immunoprecipitated with antiserum to LT and separated by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) followed by fluorography. Two molecular weight forms of LT with different rates of release were found both in cell supernatants and cell extracts. Monensin, a sodium ionophore, inhibited the release of LT. LT still appeared in two molecular weight forms after deglycosylation with N-glycanase. Treatment of cells with swainsonine followed by digestion of released LT with endoglycosidase H (endo H) demonstrated that the oligosaccharides were of the complex type. Subcellular fractionation of cells on Percoll density gradients demonstrated that intracellular LT is located to intermediate density fractions. No LT was found in the high density fractions corresponding to lysosomes. Phorbol 12-myristate 13-acetate induced production of tumor necrosis factor (TNF) in the B-lymphoblastoid cell line RPMI-1788. In conclusion, we have demonstrated the presence of two distinct molecular weight forms of LT, which contain N-linked oligosaccharides of the complex type.
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Linfocitos B/metabolismo , Linfotoxina-alfa/biosíntesis , Linfocitos T/metabolismo , Northern Blotting , Compartimento Celular/efectos de los fármacos , Línea Celular , Glicosilación , Humanos , Linfotoxina-alfa/química , Linfotoxina-alfa/genética , Peso Molecular , Monensina/farmacología , ARN Mensajero/genética , Factor de Necrosis Tumoral alfa/biosíntesisRESUMEN
CONTEXT: A potentially altered protein expression profile in orbital tissue from patients with thyroid-associated orbitopathy (TAO) is suspected. OBJECTIVE: To detect for the first time changes in proteomic patterns of orbital connective tissue in TAO and compare these with control tissue using mass spectrometry. DESIGN: Proteomics cross-sectional, comparative study. SETTING: Two academic endocrine institutions. SAMPLES: A total of 64 orbital and peripheral adipose tissue samples were collected from 39 patients with TAO and 25 control subjects. METHODS: Samples were analyzed and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technology. MAIN OUTCOME MEASURES: Mean intensity values of all identified peptides per protein. RESULTS: Thirty-one proteins were identified, of which 16 differentiated between controls and patients with TAO. Different protein patterns between orbital and peripheral adipose tissue were observed. Compared to controls, 10 proteins were markedly up-regulated (≥ 2-fold) in the orbital tissue of untreated patients: beta IV spectrin (6.2-fold), GTP binding G protein 2 (5.6-fold), POTE ankyrin domain family member F (5.4-fold), xylulokinase (4.1-fold), kinesin family member 1A and lipocalin 1 (both 3.6-fold), semicarbazide-sensitive metalloproteinase amine oxidase 3 and polymerase I transcript release factor (both 3.4-fold), cell-cycle protein elongin A binding protein 1 (3.3-fold), annexin A2 and cavin (both 3-fold), protein pointing to cell proliferation histone H4 (2.8-fold), and ADAM metallopeptidase with thrombospondin type 1 motif 14 (2.7-fold). The highest protein up-regulations were noted in the orbital tissue of medically untreated patients. Steroid therapy markedly reduced up-regulation of these proteins, foremost in nonsmokers. CONCLUSIONS: Proteins involved in tissue inflammation, adipose tissue differentiation, lipid metabolism, and tissue remodeling were up-regulated in orbital tissue of untreated patients with TAO. Steroids decreased the expression of these proteins, whereas smoking attenuated such effect.
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Oftalmopatía de Graves/genética , Oftalmopatía de Graves/metabolismo , Órbita/metabolismo , Proteómica , Enfermedades de la Tiroides/complicaciones , Tejido Adiposo/química , Tejido Adiposo/metabolismo , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Tejido Conectivo/metabolismo , Estudios Transversales , Femenino , Oftalmopatía de Graves/tratamiento farmacológico , Humanos , Metabolismo de los Lípidos/genética , Masculino , Persona de Mediana Edad , Órbita/química , Órbita/cirugía , Fumar/metabolismo , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Esteroides/uso terapéutico , Regulación hacia Arriba/efectos de los fármacos , Adulto JovenRESUMEN
The receptor system for lymphotoxin (LT) was investigated by use of the human promyelocytic HL-60 cell line. Utilizing subcellular fractionation, internalization of cell surface bound recombinant LT (rLT) and transfer to lysosomes followed by degradation was demonstrated. Binding of rLT to its cell surface receptor induced a downregulation of the receptor which was persistent for at least 6 h. Downregulation of the receptors from the cell surface by activation of protein kinase C with the diacylglycerol OAG was completely reversible but the recovery of the binding capacity was dependent on protein synthesis as it was inhibited by cycloheximide. Treatment with cycloheximide alone resulted in a loss of binding capacity with a half life of approximately 2 h, suggesting a spontaneous consumption of receptors. Affinity cross-linking revealed three ligand-receptor complexes with Mr of 85, 105 and 125 kDa. Because of a strong tendency for ligand polymerization these results suggest oligomer binding of the ligand to a single receptor molecule with an apparent Mr of 70 kDa. N-linked glycosylation constituted 4 to 5 kDa of the total molecular weight. In conclusion, we demonstrated a spontaneous internalization of the receptor for LT without recycling, and that ligand binding resulted in an irreversible downregulation of the receptor.
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Linfotoxina-alfa/metabolismo , Receptores Inmunológicos/metabolismo , Asparagina/análisis , Fraccionamiento Celular , Línea Celular , Reactivos de Enlaces Cruzados , Diglicéridos/farmacología , Electroforesis en Gel de Poliacrilamida , Activación Enzimática , Glicosilación , Humanos , Ligandos/metabolismo , Proteínas de la Membrana/metabolismo , Proteína Quinasa C/metabolismo , Receptores Inmunológicos/análisis , Receptores Inmunológicos/biosíntesis , Acetato de Tetradecanoilforbol/farmacologíaRESUMEN
Soluble forms of receptors for tumor necrosis factor (TNF) might be important for regulating the actions of TNF. Site-directed in vitro mutagenesis was employed to examine the processing of the p55 tumor necrosis factor receptor chain (TNF-R55) into soluble TNF-binding protein (TNF-R55-BP). An Asn/Val sequence close to the transmembrane region in TNF-R55 was indicated as a putative cleavage site for proteolytic processing. By mutagenesis, Asn and Val were replaced with Gly and Ala, respectively. Expression in Chinese hamster ovary (CHO) cells resulted in identical binding of ligand to mutated receptors as compared to receptors not subjected to mutagenesis. Turnover rates of receptors as judged by disappearance of TNF binding capacity after inhibition of de novo protein synthesis and downregulation in response to incubation with phorbol esters were also identical between wild-type and mutated receptors. However, mutations of the cleavage site resulted in a decreased spontaneous and phorbol ester-induced release of soluble receptor (TNF-R55-BP) which was almost abolished when both Asn and Val were mutated. Our results clearly demonstrate the importance of an Asn/Val sequence for proteolytic processing of the TNF-R55 into soluble TNF-R55-BP and indicate that phorbol ester-induced downregulation of the TNF-R55 may be dissociated from proteolytic cleavage of the receptor.
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Receptores de Superficie Celular/genética , Animales , Secuencia de Bases , Unión Competitiva , Células CHO , Cricetinae , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Receptores de Superficie Celular/biosíntesis , Receptores de Superficie Celular/química , Receptores del Factor de Necrosis Tumoral , Proteínas Recombinantes/biosíntesis , SolubilidadRESUMEN
This study clarifies the methodological pitfalls of using cross-sectional data to characterize episodic and continuous patterns of prescribing psychotropic medications in nursing homes. Although more than half of the residents in a teaching nursing home received a psychotropic drug during their 5 years of residence, less than one-quarter were continuously medicated. The authors conclude that although the rates of psychotropic prescriptions are an important entry point for concerns about quality and appropriateness of psychotropic administration to older nursing home residents, longitudinal studies including the prescribing pattern, indications, and efficacy are needed to determine more clinically meaningful indicators of quality care.