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1.
Ann Oncol ; 27(2): 332-8, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26578727

RESUMO

BACKGROUND: MicroRNAs (miRNAs) have been identified as key players in posttranscriptional gene regulation and have a significant impact on basal cell carcinoma (BCC) development. The Sonic hedgehog pathway inhibitor vismodegib has been approved for oral therapy of metastatic or advanced BCC. Here, a high-throughput miRNA sequencing analysis was carried out to identify differentially expressed miRNAs and possible novel miRNA candidates in vismodegib-treated BCC tissue. Additionally, we described our surgical experience with neoadjuvant oral vismodegib therapy. PATIENTS AND METHODS: A punch biopsy (4 mm) from a patient with an extensive cranial BCC under oral vismodegib therapy and a corresponding nonlesional epithelial skin biopsy were harvested. Total RNA was isolated, after which a sequencing cDNA library was prepared, and cluster generation was carried out, which was followed by an ultra-high-throughput miRNA sequencing analysis to indicate the read number of miRNA expression based on miRBase 21. In addition to the identification of differentially expressed miRNAs from RNA sequencing data, additional novel miRNA candidates were determined with a tool for identifying new miRNA sequences (miRDeep2). RESULTS: We identified 33 up-regulated miRNAs (fold change ≥2) and 39 potentially new miRNA candidates (miRDeep scores 0-43.6). A manual sequence analysis of the miRNA candidates on the genomic locus of chromosome 1 with provisional IDs of chr1_1913 and chr1_421 was further carried out and rated as promising (chr1_1913) and borderline (chr1_421). Histopathology revealed skip lesions in clinically healthy appearing skin at the tumor margins, which were the cause of seven re-excisions by micrographic controlled surgery to achieve tumor-free margins. CONCLUSION: miRNA sequencing revealed novel miRNA candidates that need to be further confirmed in functional Dicer knockout studies. Clinically, on the basis of our surgical experience described here, neoadjuvant vismodegib therapy in BCC appears to impede histopathologic evaluations with effects on surgical therapy. Thus, larger studies are necessary, but are not preferable at this time if other options are available.


Assuntos
Carcinoma Basocelular/genética , Regulação Neoplásica da Expressão Gênica/genética , MicroRNAs/genética , Neoplasias Cutâneas/genética , Pele/patologia , Idoso , Anilidas/uso terapêutico , Antineoplásicos/uso terapêutico , Sequência de Bases , Biópsia , Carcinoma Basocelular/tratamento farmacológico , Carcinoma Basocelular/cirurgia , Feminino , Proteínas Hedgehog/antagonistas & inibidores , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Dados de Sequência Molecular , Piridinas/uso terapêutico , Análise de Sequência de RNA , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/cirurgia
2.
Nature ; 465(7296): 322-5, 2010 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-20485429

RESUMO

Supernovae are thought to arise from two different physical processes. The cores of massive, short-lived stars undergo gravitational core collapse and typically eject a few solar masses during their explosion. These are thought to appear as type Ib/c and type II supernovae, and are associated with young stellar populations. In contrast, the thermonuclear detonation of a carbon-oxygen white dwarf, whose mass approaches the Chandrasekhar limit, is thought to produce type Ia supernovae. Such supernovae are observed in both young and old stellar environments. Here we report a faint type Ib supernova, SN 2005E, in the halo of the nearby isolated galaxy, NGC 1032. The 'old' environment near the supernova location, and the very low derived ejected mass ( approximately 0.3 solar masses), argue strongly against a core-collapse origin. Spectroscopic observations and analysis reveal high ejecta velocities, dominated by helium-burning products, probably excluding this as a subluminous or a regular type Ia supernova. We conclude that it arises from a low-mass, old progenitor, likely to have been a helium-accreting white dwarf in a binary. The ejecta contain more calcium than observed in other types of supernovae and probably large amounts of radioactive (44)Ti.

3.
Anaesthesist ; 65(11): 841-846, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27742969

RESUMO

AIM: In addition to assessing stress-coping strategies in patients, equal attention should be paid to health-care professionals. The literature on the stress-coping strategies of emergency physicians - health-care professionals who are frequently subject to stress in a fast-paced clinical setting - is scant. Therefore, we aimed to investigate the stress-coping strategies of emergency-care physicians (ECPs) in Germany. METHODS: We conducted a cross-sectional study by approaching German Associations of Emergency Medicine Physicians and the two largest ECP recruitment agencies in Germany to invite their members to participate. We used the German Stress Coping Strategies Inventory ("Stressverarbeitungsfragebogen" SVF-78) to generate stress-coping scores that would cover both positive and negative strategies. Differences according to sex were also examined. Analyses including chi-square test, t test, and multinomial logistic regression modeling were performed. RESULTS: A total of 459 German ECPs were included in the study. Compared with men, women tended to have negative coping strategies (beta = 1.77, p < 0.001). Specifically, women tended to use social support (beta = 1.55, p = 0.002), avoidance (beta = 2.59, p < 0.001), escape (beta = 1.39, p = 0.004), rumination (beta = 1.58, p < 0.001), and resignation (beta = 2.09, p < 0.001), while being less likely than men to rely on minimization and denial of guilt. CONCLUSION: ECPs experience stress in the same manner as patients and other professionals, and they must address and cope with stress appropriately. For future research, studies with a longitudinal approach to monitor the underlying mechanisms are suggested. For clinical practice and policy-making, structural changes in work patterns and psychological support should be considered, which may be of particular benefit for female ECPs.


Assuntos
Adaptação Psicológica , Serviços Médicos de Emergência , Médicos/psicologia , Estresse Psicológico/psicologia , Adulto , Esgotamento Profissional , Estudos Transversais , Negação em Psicologia , Feminino , Alemanha , Humanos , Masculino , Saúde Mental , Testes Neuropsicológicos , Projetos Piloto , Fatores Sexuais , Apoio Social
4.
Br J Dermatol ; 167(4): 847-55, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22540308

RESUMO

BACKGROUND: Perturbations in the expression profiles of microRNAs (miRNAs) have been reported for a variety of different cancers. Differentially expressed miRNAs have not been systematically evaluated in basal cell carcinoma (BCC) of the skin. OBJECTIVES: To initiate a microarray-based miRNA profiling study to identify specific miRNA candidates that are differentially expressed in BCC. METHODS: Patients with BCC (n = 7) were included in this study. Punch biopsies were harvested from the tumour centre (lesional, n = 7) and from adjacent nonlesional skin (intraindividual control, n = 7). Microarray-based miRNA expression profiles were obtained on an Agilent platform using miRBase 16 screening for 1205 Homo sapiens (hsa)-miRNA candidates. To validate the microarray data, the expression of seven dysregulated miRNAs was measured by TaqMan quantitative real-time reverse transcription polymerase chain reaction. RESULTS: We identified 16 significantly upregulated (hsa-miR-17, hsa-miR-18a, hsa-miR-18b, hsa-miR-19b, hsa-miR-19b-1*, hsa-miR-93, hsa-miR-106b, hsa-miR-125a-5p, hsa-miR-130a, hsa-miR-181c, hsa-miR-181c*, hsa-miR-181d, hsa-miR-182, hsa-miR-455-3p, hsa-miR-455-5p and hsa-miR-542-5p) and 10 significantly downregulated (hsa-miR-29c, hsa-miR-29c*, hsa-miR-139-5p, hsa-miR-140-3p, hsa-miR-145, hsa-miR-378, hsa-miR-572, hsa-miR-638, hsa-miR-2861 and hsa-miR-3196) miRNAs in BCC compared with nonlesional skin. Data mining revealed connections to many tumour-promoting pathways, such as the Hedgehog and the mitogen-activated protein kinase/extracellular signal-regulated kinase signalling cascades. CONCLUSIONS: This study identified several miRNA candidates that may play a role in the molecular pathogenesis of BCC.


Assuntos
Carcinoma Basocelular/genética , Regulação Neoplásica da Expressão Gênica/fisiologia , MicroRNAs/genética , RNA Neoplásico/genética , Neoplasias Cutâneas/genética , Idoso , Idoso de 80 Anos ou mais , Carcinoma Basocelular/metabolismo , Estudos de Casos e Controles , Regulação para Baixo , Feminino , Perfilação da Expressão Gênica/métodos , Humanos , Masculino , Análise em Microsséries , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real , Neoplasias Cutâneas/metabolismo
5.
Eur Surg Res ; 43(3): 291-7, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19672084

RESUMO

BACKGROUND: Procalcitonin (PCT) is an established laboratory marker for disease severity in patients with infection and sepsis. In addition, PCT has been shown to be an effective marker for a limited number of localized infections. However, whether or not PCT has any diagnostic value for acute appendicitis, still remains unclear. The purpose of this prospective bicenter study was, therefore, to determine whether or not the PCT levels in the serum of patients with acute appendicitis have any diagnostic value. METHODS: This prospective study included 103 patients who received an appendectomy, based on the clinical diagnosis of acute appendicitis, in a surgical department of an academic teaching hospital in Germany or in a county hospital in Spain. White blood cell count (WBC), C-reactive protein (CRP) and procalcitonin (PCT) values were determined preoperatively. All appendectomy specimens were sent for routine histopathological evaluation. Based on this information, the patients were assigned to 1 of 5 groups that reflected the severity of the appendicitis. RESULTS: Of the 103 patients who were included in the study, 98 had appendicitis. Fourteen (14.3%) showed an increase in PCT values. Of those 14, 4 had a serum PCT >0.5 ng/ml, 9 had a PCT value >2-10 ng/ml and 1 had a PCT value >10 ng/ml. The sensitivity of PCT was calculated to be 0.14. The mean WBC value was 13.0/nl (+/- 5.2, 3.4-31), and for CRP it was 8.8 mg/dl (+/- 13, 0-60.2). The values of CRP, WBC and PCT increased with the severity of the appendicitis. CONCLUSIONS: PCT is potentially increased in rare cases of severe inflammation and, in particular, after appendiceal perforation or gangrenous appendicitis. However, its remarkably low sensitivity prohibits its routine use for the diagnosis of appendicitis.


Assuntos
Apendicite/sangue , Calcitonina/sangue , Precursores de Proteínas/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Apendicite/diagnóstico , Apendicite/cirurgia , Biomarcadores/sangue , Peptídeo Relacionado com Gene de Calcitonina , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Adulto Jovem
6.
Acta Chir Plast ; 49(3): 67-70, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18051585

RESUMO

Skin cancer on the nose is commonly treated with surgical excision resulting in defects that require closure. The surgeon is faced with many reconstructive options. The paramedian forehead flap is one commonly used technique. In this study we describe the bilateral cheek-to-nose advancement flap as an alternative to the paramedian forehead flap in patients with strong nasolabial folds and prominent cheek tissue laxity, who require closure of MOHS surgery defects on the nasal dorsum and sidewall. Twelve patients were treated with the latter flap and evaluated after 2 weeks and 6 months. The patients' subjective and the surgeons' objective evaluation after 6 months were either completely satisfied or satisfied. The bilateral cheek-to-nose advancement flap is a reliable tool in the interventional portfolio of the reconstructive surgeon.


Assuntos
Bochecha/cirurgia , Testa/cirurgia , Nariz/cirurgia , Rinoplastia/métodos , Transplante de Pele/métodos , Retalhos Cirúrgicos , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
7.
Biochim Biophys Acta ; 665(1): 34-9, 1981 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-7197161

RESUMO

Reduction of fatty acids to alcohols in gourami roe homogenates and fractions thereof was studied. The reducing activity is associated with the microsomal fraction. Activation of the acid and NADPH as reducing cofactor are required. The optimal pH for reduction is between 6.5 and 7.5. Reduction rates were highest for palmitic acid and were about half of that for oleic and linoleic acids. In contrast to the equal reduction rates of the latter acids in vitro, the percentages of oleyl and linoleyl alcohols in wax esters are greatly different in vivo. Very small amounts of aldehyde are found during the reduction and some substrate label is incorporated into the phospholipids. The traces of triacylglycerols in roe lipids are not markedly labelled. In homogenates, newly formed as well as added substrate alcohol is efficiently incorporated into wax esters. Roe homogenate is capable also of oxidizing fatty alcohol to acid. In contrast to reduction, oxidation proceeds with either NADP+ or NAD+ as cofactor. Only a small portion of the newly formed acid is esterified.


Assuntos
Ácidos Graxos/metabolismo , Álcoois Graxos/metabolismo , Peixes/metabolismo , Óvulo/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Coenzima A/metabolismo , Feminino , Magnésio/metabolismo , NADP/metabolismo , Ácido Oleico , Ácidos Oleicos/metabolismo , Oxirredução , Ácidos Palmíticos/metabolismo
8.
Biochim Biophys Acta ; 751(3): 455-61, 1983 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-6849955

RESUMO

A mixture of long-chain furan fatty acids was prepared as methyl esters from testes lipids of Northern pike (Esox lucius). Upon feeding these esters to rats, dicarboxylic acids, which still contained the furan structure, were found in the urine. The first phase of a rapid but incomplete catabolism is beta-oxidation of the proximal chain of the furan fatty acids. It proceeds to a distance of three carbon atoms from the ring. omega-Oxidation of the terminal alkyl chain, followed by alpha-oxidation gives rise to a second alkylcarboxyl chain with five carbon atoms or less. The ring methyl substituents of the precursor acids seem to be more resistant to oxidation than the alkyl substituent with three or five carbon atoms. The urinary catabolites from furan fatty acids in the rat are similar to furan acids found in human urine, but only one of the structures occurs in both sources.


Assuntos
Ácidos Graxos/metabolismo , Furanos/metabolismo , Animais , Ácidos Graxos/urina , Peixes , Furanos/urina , Masculino , Ratos , Ratos Endogâmicos , Especificidade da Espécie
9.
Biochim Biophys Acta ; 575(3): 318-26, 1979 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-229908

RESUMO

Oxidation of fatty alcohols to acids in gourami caeca was investigated by measuring the reduction of NAD+ and the formation of labeled hexadecanoic acid from [1(-14)C]hexadecanol. Virtually all dehydrogenase activity is in the microsomal fraction. Maximal activity is obtained with NAD+ as cofactor whereas with NADP+ 60% of that activity is obtained. The enzyme is rather specific for long chain alcohols and 2 NADH are formed for each molecule of hexadecanol oxidized to acid. It is stabilized by mercaptoethanol, and completely inhibited by p-chloromercuribenzoate. The activity is optimal at pH 9.5. At higher pH, small amounts of aldehyde are found. The first reaction in the sequence, fatty alcohol leads to aldehyde leads to acid seems to occur under the more physiological condition at a much slower rate than the second reaction so that free aldehyde is not detected. Addition of palmitic acid indicated an uncompetitive product inhibition. The oxidation of alcohol to acid is reversible only to a very minor extent even in the presence of NADPH, CoA, ATP and Mg2+. Location, activity and properties of the enzyme are in agreement with the earlier observation from dietary experiments that in the gourami fatty alcohols of wax esters are oxidized to acids in the course of absorption.


Assuntos
Oxirredutases do Álcool/metabolismo , Ceco/metabolismo , Álcoois Graxos/metabolismo , Peixes/metabolismo , Animais , Hexanóis/metabolismo , NAD/metabolismo , Especificidade por Substrato
10.
Biochim Biophys Acta ; 799(2): 143-50, 1984 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-6428462

RESUMO

Compounds with a conjugated oxo-ene-oxo system were tested for inhibition of blood platelet aggregation. All compounds with this structure in trans configuration were effective inhibitors of aggregation induced by thrombin and by arachidonic acid. While the oxo-trans-ene-oxo system is prerequisite for such activity, other structural features of the compounds may be varied without loss of activity. Inhibition is exemplified by 9,12-dioxo-trans-10- and 10,13-dioxo-trans-11-octadecenoic acids and their methyl esters, by 11,14-dioxo-trans-12- eicosenoic acid, by 4,7-dioxo-trans-5- decene and by trans- dibenzoylethylene . The half-inhibition concentrations are in the order of 2-6 microM, with complete inhibition at 8-20 microM. According to experiments with the inhibiting 9,12-dioxo-trans-10-octadecenoic acid, the normal oxygenation of exogenous arachidonic acid by platelets is not affected but the thrombin-induced internal release of this acid seems to be abolished by the inhibitor. The inhibition of aggregation in the presence of exogenous arachidonic acid and its products suggests that the inhibitor also interferes with other events leading to aggregation. By implication from other properties of the oxo-trans-ene-oxo system, reaction with SH groups may be a mechanism for inhibition.


Assuntos
Ácidos Graxos Insaturados/farmacologia , Cetoácidos/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Ácido Araquidônico , Ácidos Araquidônicos/farmacologia , Plaquetas/metabolismo , Relação Dose-Resposta a Droga , Humanos , Consumo de Oxigênio/efeitos dos fármacos , Relação Estrutura-Atividade , Trombina/farmacologia
11.
Biochim Biophys Acta ; 793(3): 429-34, 1984 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-6712980

RESUMO

In vivo experiments on interconversions of furan fatty acids in fish are described. Administration of 2- or 3-14C-labelled furan fatty acids showed that the heterocycle does not interfere with conversions at the carboxyl group, such as shortening and elongating the chain, or its reduction to alcohol. There was no indication for desaturation of proximal chains, methylation or demethylation of the ring, or changes in the terminal chains. According to these restricted metabolic correlations, the furan fatty acids can be classified in specific structural families of bis-homologs. Distinct parent furan compounds are likely for each of these families. [1-14C]Acetate was incorporated by fish into furan fatty acids. Their chemical oxidation showed that only the resulting dicarboxylic fragments were labelled. They represent the proximal chain including alpha-C of the ring. Label was not found in the monocarboxylic acids which represent terminal chains with alpha'-C, and ring-methyl substituents with beta- and beta'-C. Accordingly, fish do not synthesize from acetate the terminal alkyl chain including the carbons in the cyclic portion of the furan fatty acids.


Assuntos
Ácidos Graxos/metabolismo , Peixes/metabolismo , Furanos/metabolismo , Animais , Oxirredução
12.
Curr Cancer Drug Targets ; 15(6): 452-62, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26282545

RESUMO

A major breakthrough in cancer immunotherapy was the discovery of immune checkpoint proteins, which function to effectively inhibit the immune system through various mechanisms. The first of such molecules shown to inhibit both T-cell proliferation and IL-2 production was cytotoxic T-lymphocyte associated protein 4 (CTLA-4). With this discovery, efforts turned to blocking this inhibitory pathway in an attempt to activate dormant T-cells directed at cancer cells. The first antibody directed against CTLA-4, ipilimumab, was quickly ushered into clinical trials and was approved by the US Food and Drug Administration (FDA) for the treatment of metastatic melanoma in 2011. Following the success of ipilimumab, other immune checkpoints were studied as possible targets for inhibition. One such interaction was that of the programmed cell death-1 (PD-1) T-cell receptor and its ligand found on many cancer cells, programmed death-ligand 1 (PD-L1). Unfortunately, the untoward effects of blocking the immune system's natural inhibitory mechanisms have manifested clinically as diarrhea, rash, and hepatitis. Nevertheless, the exciting field of immune checkpoint inhibitors offers a potential curative option for many cancer patients who previously had a more dismal prognosis. The authors aim to provide a comprehensive review of the literature and update on the use of CTLA-4, PD-1 and PD-L1 targeted therapy in the treatment of cancer and other molecules still in the early development phase.


Assuntos
Anticorpos/uso terapêutico , Antineoplásicos/uso terapêutico , Descoberta de Drogas/métodos , Imunoterapia/métodos , Terapia de Alvo Molecular/métodos , Neoplasias/tratamento farmacológico , Animais , Anticorpos/efeitos adversos , Antineoplásicos/efeitos adversos , Antígeno B7-H1/antagonistas & inibidores , Antígeno B7-H1/imunologia , Antígeno CTLA-4/antagonistas & inibidores , Antígeno CTLA-4/imunologia , Humanos , Imunoterapia/efeitos adversos , Terapia de Alvo Molecular/efeitos adversos , Neoplasias/imunologia , Neoplasias/metabolismo , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptor de Morte Celular Programada 1/imunologia , Transdução de Sinais/efeitos dos fármacos , Resultado do Tratamento
13.
J Surg Case Rep ; 2015(7)2015 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-26173437

RESUMO

A 61-year-old female with a past medical history significant for von Hippel-Lindau (VHL) syndrome presented with multiple bilateral pulmonary lesions found on surveillance computed tomography scan. Positron emission tomography demonstrated avidity in a lesion in the right upper lobe. After an equivocal biopsy, a lobectomy via a thoracoscopic approach was performed as this lesion was concerning for a primary lung cancer. Pathology revealed a diagnosis of pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma. To our knowledge, this is the first reported case of a pulmonary MALT lymphoma in a patient with VHL.

14.
Lipids ; 6(8): 562-6, 1971 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27519514

RESUMO

Methyl U-(14)C oleate was fed to mature male and female gouramis (Trichogaster cosby) and the radioactivity in lipids measured over a period of four months. Initial incorporations were 70-80% and more than half of that was still in the lipids at the end of the experiment. Very little conversion of the 18∶1 chain had occurred. Main storage of the labeled 18∶1 chain was in the wax esters of the roe and in the triglycerides of the body. In the wax esters, 18∶1 occurred in both the alcohol and acid moieties. Initially the females had less radioactivity in the triglycerides than in the wax esters but at the end of the experiment this was reversed. An appreciable amount of 18∶1 had been transferred from roe to body lipids. The biological half life of 18∶1 in gouramis is estimated to be about four months. This time is equal for males and females although translocation from roe to body and transformation of wax ester to triglyceride take place in the female, whereas wax esters do not play any role in the lipid metabolism of the male.

15.
Lipids ; 10(11): 695-702, 1975 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-1196019

RESUMO

Fatty acids, recently reported as constituents of certain fish lipids, were identified to be derivatives of furan (furanoid fish fatty acids). 12,15-Epoxy-13,14-dimethyleicosa-12,14-dienoic acid is predominant among the furan acids and is associated with bis-homologs in regard to chain length. Monomethyl acids, such as 12,15-epoxy-13-methyleicosa-12,14-dienoic, are present in appreciable amounts. The structures were concluded from oxidative degradations, from mass spectrometry of methyl esters of the novel acids and fatty acids derived from them by opening the ring, and from nuclear magnetic resonance, infrared, and Raman spectra. The results from chemical procedures and from spectrometric methods were in agreement with those obtained with authentic methyl 9,12-epoxyoctadeca-9,11-dienoate. The number of substituents at the furan ring greatly influences hydrogenation, hydrogenolysis, and hydrolysis reactions of the ring.


Assuntos
Ácidos Graxos Insaturados/análise , Furanos/análise , Animais , Cromatografia Gasosa , Peixes , Lasers , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Oxirredução , Espalhamento de Radiação , Espectrofotometria Infravermelho , Espectrofotometria Ultravioleta , Análise Espectral
16.
Aviat Space Environ Med ; 74(6 Pt 1): 633-7, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12793534

RESUMO

BACKGROUND: The operation of high-performance aircraft requires pilots to apply finely graded forces on controls. Since they are often exposed to high levels of acceleration in flight, we investigated to what extent this ability is degraded in such an environment. METHODS: Twelve healthy non-pilot volunteers were seated in the gondola of a centrifuge and their performance was tested at normal gravity (1 G) and while exposed to sustained forces of 1.5 G and 3 G oriented from head to foot (+Gz). Using an isometric joystick, they attempted to produce force vectors with specific lengths and directions commanded in random order by a visual display. RESULTS: Acceleration had substantial effects on the magnitude of produced force. Compared with 1 G, maximum produced force was about 2 N higher at 1.5 G and about 10 N higher at 3 G. The size of this effect was constant across the different magnitudes, but varied with the direction of the prescribed force. CONCLUSIONS: Acceleration degrades control of force production. This finding may indicate that the motor system misinterprets the unusual gravitoinertial environment and/or that proprioceptive feedback is degraded due to increased muscle tone. The production of excessive isometric force could affect the safe operation of high-performance aircraft.


Assuntos
Medicina Aeroespacial , Hipergravidade , Aceleração , Aeronaves , Centrifugação , Humanos
17.
Biol Psychiatry ; 76(1): 47-56, 2014 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-24239129

RESUMO

BACKGROUND: Chronic methamphetamine (METH) exposure causes neuroadaptations at glutamatergic synapses. METHODS: To identify the METH-induced epigenetic underpinnings of these neuroadaptations, we injected increasing METH doses to rats for 2 weeks and measured striatal glutamate receptor expression. We then quantified the effects of METH exposure on histone acetylation. We also measured METH-induced changes in DNA methylation and DNA hydroxymethylation. RESULTS: Chronic METH decreased transcript and protein expression of GluA1 and GluA2 alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) and GluN1 N-methyl-D-aspartate receptor subunits. These changes were associated with altered electrophysiological glutamatergic responses in striatal neurons. Chromatin immunoprecipitation-polymerase chain reaction revealed that METH decreased enrichment of acetylated histone H4 on GluA1, GluA2, and GluN1 promoters. Methamphetamine exposure also increased repressor element-1 silencing transcription factor (REST) corepressor 1, methylated CpG binding protein 2, and histone deacetylase 2 enrichment, but not of sirtuin 1 or sirtuin 2, onto GluA1 and GluA2 gene sequences. Moreover, METH caused interactions of REST corepressor 1 and methylated CpG binding protein 2 with histone deacetylase 2 and of REST with histone deacetylase 1. Surprisingly, methylated DNA immunoprecipitation and hydroxymethylated DNA immunoprecipitation-polymerase chain reaction revealed METH-induced decreased enrichment of 5-methylcytosine and 5-hydroxymethylcytosine at GluA1 and GluA2 promoter sequences. Importantly, the histone deacetylase inhibitor, valproic acid, blocked METH-induced decreased expression of AMPAR and N-methyl-D-aspartate receptor subunits. Finally, valproic acid also attenuated METH-induced decrease H4K16Ac recruitment on AMPAR gene sequences. CONCLUSIONS: These observations suggest that histone H4 hypoacetylation may be the main determinant of METH-induced decreased striatal glutamate receptor expression.


Assuntos
Corpo Estriado/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Epigênese Genética/efeitos dos fármacos , Metanfetamina/farmacologia , Receptores de AMPA/genética , Receptores de N-Metil-D-Aspartato/genética , Acetilação/efeitos dos fármacos , Animais , Corpo Estriado/metabolismo , Corpo Estriado/fisiologia , Metilação de DNA/efeitos dos fármacos , Proteínas de Ligação a DNA/metabolismo , Histona Desacetilase 1/antagonistas & inibidores , Histona Desacetilase 1/metabolismo , Histona Desacetilase 2/antagonistas & inibidores , Histona Desacetilase 2/metabolismo , Histonas/metabolismo , Masculino , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Ratos , Receptores de AMPA/biossíntese , Receptores de N-Metil-D-Aspartato/biossíntese , Proteínas Repressoras/metabolismo , Sirtuína 1/metabolismo , Sirtuína 2/metabolismo , Ácido Valproico/farmacologia
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