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1.
Space Sci Rev ; 218(8): 72, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36514324

RESUMO

The NASA InSight Lander on Mars includes the Heat Flow and Physical Properties Package HP3 to measure the surface heat flow of the planet. The package uses temperature sensors that would have been brought to the target depth of 3-5 m by a small penetrator, nicknamed the mole. The mole requiring friction on its hull to balance remaining recoil from its hammer mechanism did not penetrate to the targeted depth. Instead, by precessing about a point midway along its hull, it carved a 7 cm deep and 5-6 cm wide pit and reached a depth of initially 31 cm. The root cause of the failure - as was determined through an extensive, almost two years long campaign - was a lack of friction in an unexpectedly thick cohesive duricrust. During the campaign - described in detail in this paper - the mole penetrated further aided by friction applied using the scoop at the end of the robotic Instrument Deployment Arm and by direct support by the latter. The mole tip finally reached a depth of about 37 cm, bringing the mole back-end 1-2 cm below the surface. It reversed its downward motion twice during attempts to provide friction through pressure on the regolith instead of directly with the scoop to the mole hull. The penetration record of the mole was used to infer mechanical soil parameters such as the penetration resistance of the duricrust of 0.3-0.7 MPa and a penetration resistance of a deeper layer ( > 30 cm depth) of 4.9 ± 0.4 MPa . Using the mole's thermal sensors, thermal conductivity and diffusivity were measured. Applying cone penetration theory, the resistance of the duricrust was used to estimate a cohesion of the latter of 2-15 kPa depending on the internal friction angle of the duricrust. Pushing the scoop with its blade into the surface and chopping off a piece of duricrust provided another estimate of the cohesion of 5.8 kPa. The hammerings of the mole were recorded by the seismometer SEIS and the signals were used to derive P-wave and S-wave velocities representative of the topmost tens of cm of the regolith. Together with the density provided by a thermal conductivity and diffusivity measurement using the mole's thermal sensors, the elastic moduli were calculated from the seismic velocities. Using empirical correlations from terrestrial soil studies between the shear modulus and cohesion, the previous cohesion estimates were found to be consistent with the elastic moduli. The combined data were used to derive a model of the regolith that has an about 20 cm thick duricrust underneath a 1 cm thick unconsolidated layer of sand mixed with dust and above another 10 cm of unconsolidated sand. Underneath the latter, a layer more resistant to penetration and possibly containing debris from a small impact crater is inferred. The thermal conductivity increases from 14 mW/m K to 34 mW/m K through the 1 cm sand/dust layer, keeps the latter value in the duricrust and the sand layer underneath and then increases to 64 mW/m K in the sand/gravel layer below. Supplementary Information: The online version contains supplementary material available at 10.1007/s11214-022-00941-z.

2.
JDR Clin Trans Res ; 7(2): 127-134, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-33949224

RESUMO

INTRODUCTION: Rates of periodontal disease and tooth loss are increased in individuals with rheumatoid arthritis (RA). Understanding factors that contribute to the increased burden of periodontal disease in RA is critical to improving oral health and arthritis outcomes. OBJECTIVES: To determine the perceptions held by people with RA relating to their oral health, to identify patient-centered priorities for oral health research, and to inform optimal strategies for delivering oral health knowledge. METHODS: Semistructured interviews were conducted with patients with RA. Recorded interview transcripts were iteratively reviewed to reveal surface and latent meaning and to code for themes. Constructs were considered saturated when no new themes were identified in subsequent interviews. We report themes with representative quotes. RESULTS: Interviews were conducted with 11 individuals with RA (10 women [91%]; mean age, 68 y), all of whom were taking RA medication. Interviews averaged 19 min (range, 8 to 31 min) and were mostly conducted face-to-face. Three overall themes were identified: 1) knowledge about arthritis and oral health links; 2) oral health care in RA is complicated, both in personal hygiene practices and in professional oral care; and 3) poor oral health is a source of shame. Participants preferred to receive oral health education from their rheumatologists or dentists. CONCLUSIONS: People with RA have unique oral health perceptions and experience significant challenges with oral health care due to their arthritis. Adapting oral hygiene recommendations and professional oral care delivery to the needs of those with arthritis are patient priorities and are required to improve satisfaction regarding their oral health. KNOWLEDGE TRANSLATION STATEMENT: Patients living with long-standing rheumatoid arthritis described poor oral health-related quality of life and multiple challenges with maintaining optimal oral health. Study findings indicate a need for educational materials addressing oral health maintenance for patients with rheumatic diseases and their providers.


Assuntos
Artrite Reumatoide , Perda de Dente , Idoso , Artrite Reumatoide/complicações , Feminino , Humanos , Masculino , Saúde Bucal , Higiene Bucal , Qualidade de Vida , Perda de Dente/complicações
3.
Nat Commun ; 12(1): 6756, 2021 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-34815402

RESUMO

Orbital and surface observations can shed light on the internal structure of Mars. NASA's InSight mission allows mapping the shallow subsurface of Elysium Planitia using seismic data. In this work, we apply a classical seismological technique of inverting Rayleigh wave ellipticity curves extracted from ambient seismic vibrations to resolve, for the first time on Mars, the shallow subsurface to around 200 m depth. While our seismic velocity model is largely consistent with the expected layered subsurface consisting of a thin regolith layer above stacks of lava flows, we find a seismic low-velocity zone at about 30 to 75 m depth that we interpret as a sedimentary layer sandwiched somewhere within the underlying Hesperian and Amazonian aged basalt layers. A prominent amplitude peak observed in the seismic data at 2.4 Hz is interpreted as an Airy phase related to surface wave energy trapped in this local low-velocity channel.

4.
Appetite ; 166: 105325, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34062176

RESUMO

Use of oral nutritional supplements (ONS) in undernourished patients has proven clinical benefits, but this can be hampered by low adherence due to poor experience of palatability. Many patients, particularly older patients, experience hyposalivation which can cause taste changes and reduce the enjoyment of foods. The aim of this study was to investigate differences in the temporal consumption experience (comprising sensory perception, in-mouth aroma release and subjective appetite) of a clinically relevant portion of ONS, for groups differing in saliva flow rates (SFR). The SFR (mL/min) of thirty healthy individuals was measured on three occasions. This data was used to categorise individuals into three groups using quartile analysis: low flow (LF) (0.3-0.6 mL/min, n = 5), medium flow (MF) (0.7-1.2 mL/min, n = 16) and high flow (HF) (1.3-1.8 mL/min, n = 9). Over the consumption of eight 15 mL sips of ONS, individuals rated their sensory perception and subjective appetite perception using line scales. Additionally, in-mouth aroma release was measured for each sip, using atmospheric pressure chemical ionisation (APCI). Compared with the MF and HF group, the LF group reported a significantly greater increase of mouth-drying over increased sips (p = 0.02). The LF group also experienced significantly higher aftertaste perception (p < 0.001), and more intense in-mouth aroma release (p = 0.015), compared with the HF group. These findings occurred concurrently with relatively lower hunger sensations in the LF and MF group. Many patients who are prescribed ONS likely experience reduced salivary flow rates. The unique sensory experiences of these individuals should be considered in order to optimise palatability and nutritional intake.


Assuntos
Suplementos Nutricionais , Desnutrição , Apetite , Humanos , Fome , Boca
5.
Bull Seismol Soc Am ; 111(6): 2982-3002, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35001979

RESUMO

The Seismic Experiment for Interior Structure (SEIS) of the InSight mission to Mars, has been providing direct information on Martian interior structure and dynamics of that planet since it landed. Compared to seismic recordings on Earth, ground motion measurements acquired by SEIS on Mars are made under dramatically different ambient noise conditions, but include idiosyncratic signals that arise from coupling between different InSight sensors and spacecraft components. This work is to synthesize what is known about these signal types, illustrate how they can manifest in waveforms and noise correlations, and present pitfalls in structural interpretations based on standard seismic analysis methods. We show that glitches, a type of prominent transient signal, can produce artifacts in ambient noise correlations. Sustained signals that vary in frequency, such as lander modes which are affected by variations in temperature and wind conditions over the course of the Martian Sol, can also contaminate ambient noise results. Therefore, both types of signals have the potential to bias interpretation in terms of subsurface layering. We illustrate that signal processing in the presence of identified nonseismic signals must be informed by an understanding of the underlying physical processes in order for high fidelity waveforms of ground motion to be extracted. While the origins of most idiosyncratic signals are well understood, the 2.4 Hz resonance remains debated and the literature does not contain an explanation of its fine spectral structure. Even though the selection of idiosyncratic signal types discussed in this paper may not be exhaustive, we provide guidance on best practices for enhancing the robustness of structural interpretations.

6.
Surgeon ; 18(5): e1-e6, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31718929

RESUMO

BACKGROUND: Changes to working practices and increasing service demand have contributed to low morale amongst UK surgical trainees, with pressures particularly acute 'out of hours' (OOH). Surgeons may be expected to be 'on call' for multiple hospitals, or to provide remote consultations, yet healthcare systems may undermine their professional safety and patient care. This cross-sectional study sought to define the perceptions of UK-based Royal College of Surgeons of Edinburgh (RCSEd) affiliated trainees of OOH surgical care and training. METHODS: The RCSEd Trainees' Committee conducted a design-thinking exercise to produce an online questionnaire. Non-consultant grade RCSEd Members and Fellows were invited to participate. Quantitative data was analysed using descriptive statistics, and qualitative data was coded to identify emergent themes. RESULTS: One hundred and fifty-five surgeons participated. Of those surgeons working in multiple hospitals OOH (n = 16), many did not receive access cards (12[75%]) or site-specific induction (13[81%]), and 8(50%) were not confident in using local electronic investigation and records systems. Only 14/114 (12%) of the surgeons providing remote opinion had access to a consultation record system, and most perceived dissatisfaction with the system. Emergent themes from qualitative data revealed that trainee surgeons desire specific training in OOH working, concerns that OOH work experience is diminishing, and that hospital infrastructure such as IT and communications, rest facilities and catering were inadequate in facilitating safe care. CONCLUSIONS: The participants perceived that the systems supporting delivery of safe surgical care OOH were inadequate. Hospital leaders should ensure that systems minimise risk to staff and patients.


Assuntos
Plantão Médico/organização & administração , Educação de Pós-Graduação em Medicina/organização & administração , Cirurgia Geral/educação , Admissão e Escalonamento de Pessoal/organização & administração , Medicina Estatal , Competência Clínica , Estudos Transversais , Humanos , Inquéritos e Questionários , Reino Unido , Carga de Trabalho
7.
Space Sci Rev ; 215(1): 12, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30880848

RESUMO

By the end of 2018, 42 years after the landing of the two Viking seismometers on Mars, InSight will deploy onto Mars' surface the SEIS (Seismic Experiment for Internal Structure) instrument; a six-axes seismometer equipped with both a long-period three-axes Very Broad Band (VBB) instrument and a three-axes short-period (SP) instrument. These six sensors will cover a broad range of the seismic bandwidth, from 0.01 Hz to 50 Hz, with possible extension to longer periods. Data will be transmitted in the form of three continuous VBB components at 2 sample per second (sps), an estimation of the short period energy content from the SP at 1 sps and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams will be augmented by requested event data with sample rates from 20 to 100 sps. SEIS will improve upon the existing resolution of Viking's Mars seismic monitoring by a factor of ∼ 2500 at 1 Hz and ∼ 200 000 at 0.1 Hz. An additional major improvement is that, contrary to Viking, the seismometers will be deployed via a robotic arm directly onto Mars' surface and will be protected against temperature and wind by highly efficient thermal and wind shielding. Based on existing knowledge of Mars, it is reasonable to infer a moment magnitude detection threshold of M w ∼ 3 at 40 ∘ epicentral distance and a potential to detect several tens of quakes and about five impacts per year. In this paper, we first describe the science goals of the experiment and the rationale used to define its requirements. We then provide a detailed description of the hardware, from the sensors to the deployment system and associated performance, including transfer functions of the seismic sensors and temperature sensors. We conclude by describing the experiment ground segment, including data processing services, outreach and education networks and provide a description of the format to be used for future data distribution. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11214-018-0574-6) contains supplementary material, which is available to authorized users.

8.
Br J Surg ; 103(11): 1462-6, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27529453

RESUMO

BACKGROUND: The UK National Institute for Health and Care Excellence (NICE) guidelines state that carotid endarterectomy should be scheduled within 2 weeks of symptoms. The recent National Stroke Strategy has reduced the time interval to 48 h. This study aimed to review the possible delays. METHODS: This study analysed patients with confirmed transient ischaemic attack (TIA) or minor stroke, referred to a single tertiary centre clinic and followed up 1 month after the event. A questionnaire was used to collect data on the rapid-access clinic pathway, and details of previous medication and treatment. RESULTS: Some 150 patients presented with a confirmed TIA or minor stroke during a 5-month interval (June to October 2014). Fifty-one (34·0 per cent) had a history of TIA or stroke and 35 (23·3 per cent) had undergone an 'index' event in the 5 days before presentation. Forty-five patients (30·0 per cent) experienced a reduction or loss of vision. Of this group, 32 had a deficit in vision only, none of whom attributed these symptoms to a cerebrovascular event. Overall 92 (61·3 per cent) of the 150 patients had a delay in presentation to medical services. Forty-seven (31·3 per cent) had residual symptoms at the clinic appointment. Eighty-eight patients (58·7 per cent) did not think they were having a stroke and 54 (36·0 per cent) were unaware of the National Stroke Strategy (FAST campaign - Face, Arm, Speech, Time). CONCLUSION: Two-thirds of patients were not aware they were having a stroke, one-third were unaware of the FAST campaign and nearly one-third presented with eye symptoms. Inclusion of eye symptoms and reaffirmation of the need to react might avoid unnecessary delays in the presentation of patients with TIA and minor stroke.


Assuntos
Ataque Isquêmico Transitório/diagnóstico , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Acidente Vascular Cerebral/diagnóstico , Tempo para o Tratamento , Diagnóstico Tardio , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Ataque Isquêmico Transitório/cirurgia , Acidente Vascular Cerebral/cirurgia , Inquéritos e Questionários
12.
Rev Sci Instrum ; 84(2): 025103, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23464247

RESUMO

A novel, rapid and accurate calibration procedure as a means for quantitative gas desorption measurement by temperature programmed desorption (TPD) spectroscopy is presented. Quantitative measurement beyond the linear regime of the instrument is achieved by associating an instantaneous calibrated molar flow rate of gas to the detector response. This technique is based on fundamental methods, and is independently verified by comparison to the hydrogen desorption capacity of a known standard metal hydride with known stoichiometry. The TPD calibration procedure described here may be used for any pure gas, and the accuracy is demonstrated for the specific case of hydrogen.

13.
Oncogene ; 28(30): 2710-22, 2009 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-19483731

RESUMO

The role of the canonical NF-kappaB pathway in mammary tumorigenesis was investigated using a transgenic (TG) mouse expressing a dominant-negative inhibitor of kappaB (IkappaBalpha(SR (S32A/S36A))) in the mammary gland under the control of the mouse mammary tumor virus promoter (MMTV). TG and control mice were subjected to a chemical carcinogenesis protocol. Hyperkeratinized squamous metaplasias (cytokeratin-6+/p63+) sometimes with a basaloid island component, were found in both TG and control mice whereas luminal (cytokeratin-19+/MUC1+) ErbB2+ papillary and adenomatous lesions developed almost exclusively in control mice. p65/RelA- and NF-kappaB DNA-binding activity were detected in mammary luminal lesions, but rarely in squamous metaplasias. Analysis of NF-kappaB family proteins and target genes using microarray data from a cohort of human mammary tumors revealed the expression of a canonical NF-kappaB pathway, but not non-canonical pathway proteins in HER2+ luminal cancers. HER2+ tumors also showed differential regulation of specific NF-kappaB target genes relative to basal and ER+ luminal cancers. Isolation of mammary cell populations enriched for stem and progenitor cell characteristics from an NF-kappaB-EGFP reporter mouse by fluorescence-activated cell sorting demonstrated that luminal progenitors contain activated NF-kappaB whereas the mammary stem cell-enriched population, does not. Together these data suggest that the canonical NF-kappaB pathway is active in normal luminal progenitor cells before transformation and is required for the formation of mammary luminal-type epithelial neoplasias.


Assuntos
Neoplasias Mamárias Experimentais/etiologia , NF-kappa B/fisiologia , Células-Tronco Neoplásicas/metabolismo , Transdução de Sinais/fisiologia , 9,10-Dimetil-1,2-benzantraceno , Animais , Neoplasias da Mama/etiologia , Antígeno CD24/análise , Humanos , Quinase I-kappa B/análise , Integrina alfa6/análise , Vírus do Tumor Mamário do Camundongo/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Receptor ErbB-2/análise , Fator de Transcrição RelA/análise
14.
Nanotechnology ; 20(18): 185303, 2009 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-19420610

RESUMO

A gas-expanded liquid-based nanoparticle deposition technique was integrated with a critical point drying process to modify the surface of polysilicon microstructures in order to reduce the adhesion that ordinarily occurs due to dominant interfacial surface forces. Dodecanethiol-capped gold nanoparticles (AuNPs) were deposited onto arrays of cantilever beams using gas-expanded liquid technology in an effort to increase the surface roughness, thereby reducing the real contact surface area as well as changing the chemical constituents of the contacting areas. Both AuNP-coated and uncoated (native oxide surface) arrays were actuated electrostatically in order to determine the work of adhesion. The results of this study indicate that while cantilever beams with only their native oxide exhibit apparent adhesion energies of about 700 +/- 100 microJ m(-2), cantilever beam arrays coated with AuNPs exhibit an apparent adhesion energy of about 8 microJ m(-2) or less. These results indicate that metallic nanoparticle coatings can be successfully applied to micromachines and provide a drastic reduction in apparent adhesion energy.


Assuntos
Cristalização/métodos , Gases/química , Nanotecnologia/métodos , Silício/química , Titânio/química , Adesividade , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Soluções , Propriedades de Superfície
16.
J Neurol Neurosurg Psychiatry ; 75(4): 577-82, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15026500

RESUMO

OBJECTIVES: This study aimed to develop further a diary originally devised to measure the impact of multiple sclerosis (MS) as part of a cost utility study of beta interferon, and to evaluate its reliability, validity, and responsiveness in an outpatient sample of people with MS. METHODS: The original diary was further developed using qualitative and quantitative methods to ensure that it addressed the views of people with MS. The psychometric properties of the MS Symptom and Impact Diary (MSSID) were evaluated in a sample of 77 people who completed the MSSID daily for 12 weeks. Internal and test-retest reliability, discriminant and convergent validity, and responsiveness were assessed using traditional psychometric methods. RESULTS: The MSSID formed three, internally consistent scales that measured mobility, fatigue, and the overall impact of MS. The test-retest reliability of the mobility scale was adequate for individual comparisons (ICC>0.90) and the fatigue and overall impact scales were adequate for group comparisons (ICC>0.70). The MSSID was able to distinguish between clinical groups depending on clinical course, indoor ambulation status, and relapse status. It demonstrated associations with other single point instruments in the expected direction. Compared with single point instruments, its responsiveness was similar or better, especially in detecting short term improvements in functioning. CONCLUSIONS: The MSSID may provide a useful complement to currently available instruments to measure the outcomes of MS within clinical trials. Further research is needed to explore its feasibility in the context of a randomised controlled trial and its utility for clinicians.


Assuntos
Atividades Cotidianas/classificação , Prontuários Médicos , Esclerose Múltipla/diagnóstico , Papel do Doente , Atividades Cotidianas/psicologia , Adulto , Assistência Ambulatorial , Análise Custo-Benefício , Avaliação da Deficiência , Feminino , Seguimentos , Humanos , Interferon beta/economia , Interferon beta/uso terapêutico , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/tratamento farmacológico , Esclerose Múltipla/economia , Esclerose Múltipla/psicologia , Psicometria/estatística & dados numéricos , Qualidade de Vida/psicologia , Reprodutibilidade dos Testes
18.
Pediatr Nephrol ; 14(7): 562-6, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10912519

RESUMO

After birth, the acid-labile subunit (ALS) associates in the circulation with insulin-like growth factor (IGF)-I or -II and with IGF binding protein-3 (IGFBP-3) to form a 150-kilodalton complex. This association leads to the retention of IGFs in the vascular system and promotes their endocrine actions. ALS is synthesized almost exclusively in liver, and both hepatic ALS mRNA and circulating levels are increased by growth hormone (GH). Three major areas of study were pursued to better understand the regulation of ALS synthesis and its role in the circulating IGF system. First, the mouse ALS gene was isolated and shown to be organized into two exons and a single intron on chromosome 17. Second, using transient transfection studies in the rat H4-II-E hepatoma cell line and primary rat hepatocytes, the region of the mouse promoter that is responsive to GH was mapped to a nine-base pair cis-element resembling a gamma-interferon-activated sequence. The activation of the mouse ALS gene by GH is mediated by the binding of STAT5 isoforms to this sequence. Finally, an ALS knockout model was created by inactivating the ALS gene in mouse embryonic stem cells. Mice that are homozygous for the mutation grow at a slower rate after birth. This growth depression is associated with large decreases in the plasma concentrations of both IGF-I and IGFBP-3, indicating the critical role of ALS in the regulation of circulating levels of these proteins. Studies of this model will lead to a better understanding of the circulating IGF system.


Assuntos
Proteínas de Transporte/fisiologia , Glicoproteínas/fisiologia , Camundongos/fisiologia , Animais , Sangue/metabolismo , Proteínas de Transporte/química , Proteínas de Transporte/genética , Regulação da Expressão Gênica no Desenvolvimento , Glicoproteínas/química , Glicoproteínas/genética , Camundongos Knockout/genética , Peso Molecular , Somatomedinas/metabolismo
19.
Proc Natl Acad Sci U S A ; 97(12): 6868-73, 2000 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-10823924

RESUMO

Insulin-like growth factors (IGFs) I and II are important regulators of cell proliferation and differentiation. After birth, plasma IGFs, representing mostly liver-derived IGFs, circulate in ternary complexes of 150 kDa consisting of one molecule each of IGF, IGF-binding protein (IGFBP) 3, and an acid labile subunit (ALS). Onset of ALS synthesis after birth is the primary factor driving the formation of ternary complexes. Capture of IGFs by ALS is thought to allow the development of a plasma reservoir without negative effects such as hypoglycemia and cell proliferation. To evaluate the importance of ALS and ternary complexes, we have created mice in which the ALS gene has been inactivated. The mutation was inherited in a Mendelian manner, without any effects on survival rates and birth weights. A growth deficit was observed in null mice after 3 weeks of life and reached 13% by 10 weeks. This modest phenotype was observed despite reductions of 62 and 88% in the concentrations of plasma IGF-I and IGFBP-3, respectively. Increased turnover accounted for these reductions because indices of synthesis in liver and kidney were not decreased. Surprisingly, absence of ALS did not affect glucose and insulin homeostasis. Therefore, ALS is required for postnatal accumulation of IGF-I and IGFBP-3 but, consistent with findings supporting a predominant role for locally produced IGF-I, is not critical for growth. This model should be useful to determine whether presence of ALS is needed for other actions of liver-derived IGF-I and for maintenance of homeostasis in presence of high circulating levels of IGF-II.


Assuntos
Transtornos do Crescimento/etiologia , Somatomedinas/fisiologia , Animais , Metabolismo dos Carboidratos , Feminino , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/biossíntese , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/sangue , Fator de Crescimento Insulin-Like I/análise , Fator de Crescimento Insulin-Like I/biossíntese , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , RNA Mensageiro/análise , Somatomedinas/genética
20.
J Biol Chem ; 275(6): 3841-7, 2000 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-10660535

RESUMO

During catabolic diseases such as sepsis, inflammation, and infection, a state of growth hormone (GH) resistance develops in liver. This has been attributed in part to increased production of the proinflammatory cytokine interleukin-1beta (IL-1beta). To determine how IL-1beta induces GH resistance, we studied the acid-labile subunit (ALS) gene whose hepatic transcription is increased by GH via the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway. IL-1beta reduced the ability of GH to stimulate ALS mRNA in rat primary hepatocytes and ALS promoter activity in H4-II-E rat hepatoma cells. This inhibition was dependent on ALSGAS1, an element resembling a gamma-interferon activated sequence that mediates the transcriptional effects of GH. Inhibition by IL-1beta was also associated with a reduction of GH-dependent binding of STAT5 to this element after chronic (8 and 24 h), but not after acute treatment (15 min). Because these results indicated that the inhibition by IL-1beta was indirect, expression of the recently discovered suppressors of cytokine action (SOCS) was examined in liver cells. IL-1beta did not alter the expression of SOCS1, SOCS2, and CIS, indicating that they are not involved. In contrast, IL-1beta increased SOCS3 mRNA by 8-fold after 24 h of treatment, whereas GH had no effect. Forced expression of SOCS3 was just as effective as IL-1beta in reducing the GH induction of ALS promoter activity in H4-II-E rat hepatoma cells. Similar results were observed in primary rat hepatocytes. We conclude that the induction of SOCS3 by IL-1beta contributes to the development of GH resistance in liver, and represents a mechanism by which cytokines such as IL-1beta cross-talk with cytokines using the JAK-STAT pathway.


Assuntos
Proteínas de Transporte/genética , Glicoproteínas/genética , Hormônio do Crescimento/farmacologia , Interleucina-1/farmacologia , Fígado/metabolismo , Proteínas do Leite , Proteínas/metabolismo , Proteínas Repressoras , Fatores de Transcrição , Transcrição Gênica/efeitos dos fármacos , Animais , Proteínas de Ligação a DNA/metabolismo , Camundongos , Regiões Promotoras Genéticas , RNA Mensageiro/metabolismo , Ratos , Fator de Transcrição STAT5 , Transdução de Sinais , Proteína 3 Supressora da Sinalização de Citocinas , Proteínas Supressoras da Sinalização de Citocina , Transativadores/metabolismo , Ativação Transcricional/efeitos dos fármacos , Células Tumorais Cultivadas
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