Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 230
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Nature ; 542(7639): 66-70, 2017 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-28002409

RESUMO

Engineered spin-orbit coupling (SOC) in cold-atom systems can enable the study of new synthetic materials and complex condensed matter phenomena. However, spontaneous emission in alkali-atom spin-orbit-coupled systems is hindered by heating, limiting the observation of many-body effects and motivating research into potential alternatives. Here we demonstrate that spin-orbit-coupled fermions can be engineered to occur naturally in a one-dimensional optical lattice clock. In contrast to previous SOC experiments, here the SOC is both generated and probed using a direct ultra-narrow optical clock transition between two electronic orbital states in 87Sr atoms. We use clock spectroscopy to prepare lattice band populations, internal electronic states and quasi-momenta, and to produce spin-orbit-coupled dynamics. The exceptionally long lifetime of the excited clock state (160 seconds) eliminates decoherence and atom loss from spontaneous emission at all relevant experimental timescales, allowing subsequent momentum- and spin-resolved in situ probing of the SOC band structure and eigenstates. We use these capabilities to study Bloch oscillations, spin-momentum locking and Van Hove singularities in the transition density of states. Our results lay the groundwork for using fermionic optical lattice clocks to probe new phases of matter.

2.
J Intern Med ; 290(1): 190-202, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33453124

RESUMO

BACKGROUND: Mitochondria play an important role in cellular metabolism, and their dysfunction is postulated to be involved in metabolic disturbances. Mitochondrial DNA is present in multiple copies per cell. The quantification of mitochondrial DNA copy number (mtDNA-CN) might be used to assess mitochondrial dysfunction. OBJECTIVES: We aimed to investigate the cross-sectional association of mtDNA-CN with type 2 diabetes and the potential mediating role of metabolic syndrome. METHODS: We examined 4812 patients from the German Chronic Kidney Disease (GCKD) study and 9364 individuals from the Cooperative Health Research in South Tyrol (CHRIS) study. MtDNA-CN was measured in whole blood using a plasmid-normalized qPCR-based assay. RESULTS: In both studies, mtDNA-CN showed a significant correlation with most metabolic syndrome parameters: mtDNA-CN decreased with increasing number of metabolic syndrome components. Furthermore, individuals with low mtDNA-CN had significantly higher odds of metabolic syndrome (OR = 1.025; 95% CI = 1.011-1.039, P = 3.19 × 10-4 , for each decrease of 10 mtDNA copies) and type 2 diabetes (OR = 1.027; 95% CI = 1.012-1.041; P = 2.84 × 10-4 ) in a model adjusted for age, sex, smoking and kidney function in the meta-analysis of both studies. Mediation analysis revealed that the association of mtDNA-CN with type 2 diabetes was mainly mediated by waist circumference in the GCKD study (66%) and by several metabolic syndrome parameters, especially body mass index and triglycerides, in the CHRIS study (41%). CONCLUSIONS: Our data show an inverse association of mtDNA-CN with higher risk of metabolic syndrome and type 2 diabetes. A major part of the total effect of mtDNA-CN on type 2 diabetes is mediated by obesity parameters.


Assuntos
Variações do Número de Cópias de DNA , DNA Mitocondrial/genética , Diabetes Mellitus Tipo 2/genética , Síndrome Metabólica/genética , Idoso , Índice de Massa Corporal , Estudos Transversais , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/fisiopatologia , Feminino , Humanos , Masculino , Síndrome Metabólica/complicações , Síndrome Metabólica/fisiopatologia , Pessoa de Meia-Idade , Estudos Prospectivos , Triglicerídeos/sangue , Circunferência da Cintura
3.
Diabet Med ; 38(4): e14404, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-32949070

RESUMO

AIM: Diabetic neuro-osteoarthropathy (Charcot foot) is a serious form of diabetic foot syndrome, often leading to severe deformity of the foot and subsequently to ulcers and osteomyelitis. The aim of this retrospective study was to determine the success rate and long-term outcomes for a Charcot foot operation using external fixation in 115 individuals who underwent surgery between July 2008 and December 2012. METHODS: Some 115 consecutive persons, 78 (68%) men and 37 (32%) women, were enrolled in this study. The eligibility criterion for this retrospective study was reconstructive foot surgery using a Hoffmann II external fixator in diabetic and non-diabetic neuro-osteoarthropathy. The main examination parameters in the follow-up were walking ability, amputation and mortality. Average follow-up was 5.7 (± 3.2) years. RESULTS: Ninety-seven per cent of people were able to walk after the operation with bespoke shoes or an orthosis. At follow-up, 77% were able to walk and 51% were fully mobile even outside the home. Subsequent amputations were performed in 29 individuals (26%), with 17 (15%) minor and 12 (11%) major amputations. Forty-seven individuals died before follow-up, the majority (53%) from cardiovascular events. Average survival time post surgery was 4.5 (± 2.9) years. CONCLUSION: Reconstruction surgery using external fixation is a very useful method for maintaining walking ability in the case of conservatively non-treatable diabetic and non-diabetic neuro-osteoarthropathy. Individuals with severe Charcot foot disease had a low rate of major amputations. Osteomyelitis was the main reason for major amputations.


Assuntos
Artropatia Neurogênica/cirurgia , Complicações do Diabetes/cirurgia , Diabetes Mellitus/cirurgia , Fixadores Externos , Pé/cirurgia , Procedimentos de Cirurgia Plástica , Idoso , Amputação Cirúrgica/estatística & dados numéricos , Artropatia Neurogênica/diagnóstico , Artropatia Neurogênica/epidemiologia , Complicações do Diabetes/diagnóstico , Complicações do Diabetes/epidemiologia , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/epidemiologia , Pé Diabético/diagnóstico , Pé Diabético/epidemiologia , Pé Diabético/cirurgia , Feminino , Seguimentos , Pé/patologia , Fixação de Fratura/instrumentação , Fixação de Fratura/métodos , Fixação de Fratura/estatística & dados numéricos , Alemanha/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Procedimentos de Cirurgia Plástica/instrumentação , Procedimentos de Cirurgia Plástica/métodos , Procedimentos de Cirurgia Plástica/estatística & dados numéricos , Estudos Retrospectivos , Resultado do Tratamento
4.
J Intern Med ; 287(5): 569-579, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32037598

RESUMO

BACKGROUND: Dysfunctional mitochondria have an influence on inflammation and increased oxidative stress due to an excessive production of reactive oxygen species. The mitochondrial DNA copy number (mtDNA-CN) is a potential biomarker for mitochondrial dysfunction and has been associated with various diseases. However, results were partially contrasting which might have been caused by methodological difficulties to quantify mtDNA-CN. OBJECTIVE: We aimed to investigate whether mtDNA-CN is associated with peripheral arterial disease (PAD) as well as all-cause mortality and cardiovascular events during seven years of follow-up. METHODS: A total of 236 male patients with PAD from the Cardiovascular Disease in Intermittent Claudication (CAVASIC) study were compared with 249 age- and diabetes-matched controls. MtDNA-CN was measured with a well-standardized plasmid-normalized quantitative PCR-based assay determining the ratio between mtDNA-CN and nuclear DNA. RESULTS: Individuals in the lowest quartile of mtDNA-CN had a twofold increased risk for PAD which, however, was no longer significant after adjusting for leukocytes and platelets. About 67 of the 236 patients had already experienced a cardiovascular event at baseline and those in the lowest mtDNA-CN quartile had a 2.34-fold increased risk for these events (95% CI 1.08-5.13). During follow-up, 37 PAD patients died and 66 patients experienced a cardiovascular event. Patients in the lowest mtDNA-CN quartile had hazard ratios of 2.66 (95% CI 1.27-5.58) for all-cause-mortality and 1.82 (95% CI 1.02-3.27) for cardiovascular events compared with the combined quartile 2-4 (adjusted for age, smoking, CRP, diabetes, prevalent cardiovascular disease, leukocytes and platelets). CONCLUSION: This investigation supports the hypothesis of mitochondrial dysfunction in peripheral arterial disease and shows an association of low mtDNA-CNs with all-cause-mortality and prevalent and incident cardiovascular disease in PAD patients with intermittent claudication.


Assuntos
Doenças Cardiovasculares/genética , Variações do Número de Cópias de DNA , DNA Mitocondrial/genética , Doença Arterial Periférica/genética , Doenças Cardiovasculares/complicações , Doenças Cardiovasculares/mortalidade , Estudos de Casos e Controles , Variações do Número de Cópias de DNA/genética , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Doenças Mitocondriais/complicações , Doenças Mitocondriais/genética , Mortalidade , Doença Arterial Periférica/complicações , Doença Arterial Periférica/mortalidade , Modelos de Riscos Proporcionais , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Risco
5.
Ann Hematol ; 94(9): 1577-84, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26027858

RESUMO

Patients often experience bone marrow examinations (BMEs) as frightening and painful. Varying operators and uncertainty about who will perform the BME worsen their anxiety. In our study, clinical nurse specialists (CNSs) were trained to perform BMEs to ensure continuity and to test the feasibility, patient satisfaction, and biopsy quality. This exploratory evaluation assessed 574 BMEs at our tertiary center between January 2012 and February 2013, 398 BMEs performed by CNS and 176 by physicians. Our aims were to determine whether BMEs by CNS yield results similar to those of physicians, analyzing (1) patient satisfaction with the BME (a) consent and (b) performance, (2) induced pain, and (3) quality of aspirates and length of trephine biopsies. When performed by CNS, 100 % of the patients were satisfied with the consent procedure and 99 % with the BME performance (physicians 99 and 91 %, respectively). The median pain score was low when both CNS and physicians performed the BME, with no or only mild pain in 92 and 76 % of patients, respectively. Bone marrow (BM) aspirates by CNS and physicians were assessed as technically evaluable in ~70 %; moreover, the median length of trephine biopsies was similar when performed by CNS or physicians with 12 and 13 mm, respectively. In conclusion, BMEs conducted by motivated CNS and within a structured training program are feasible and yield equal outcomes compared to physicians. The use of adequate pain management during BMEs by trained and experienced operators results in an extremely rare use of sedatives, low pain scores, and high patient satisfaction.


Assuntos
Medula Óssea/patologia , Educação Continuada em Enfermagem , Enfermeiros Clínicos/educação , Dor/prevenção & controle , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
6.
Phys Rev Lett ; 112(12): 123001, 2014 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-24724647

RESUMO

Ramsey spectroscopy has become a powerful technique for probing nonequilibrium dynamics of internal (pseudospin) degrees of freedom of interacting systems. In many theoretical treatments, the key to understanding the dynamics has been to assume the external (motional) degrees of freedom are decoupled from the pseudospin degrees of freedom. Determining the validity of this approximation-known as the spin model approximation-has not been addressed in detail. Here we shed light in this direction by calculating Ramsey dynamics exactly for two interacting spin-1/2 particles in a harmonic trap. We focus on s-wave-interacting fermions in quasi one- and two-dimensional geometries. We find that in one dimension the spin model assumption works well over a wide range of experimentally relevant conditions, but can fail at time scales longer than those set by the mean interaction energy. Surprisingly, in two dimensions a modified version of the spin model is exact to first order in the interaction strength. This analysis is important for a correct interpretation of Ramsey spectroscopy and has broad applications ranging from precision measurements to quantum information and to fundamental probes of many-body systems.

7.
Horm Metab Res ; 46(11): 749-52, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25208272

RESUMO

Previous studies have shown that in diabetes mellitus, insulin-induced relaxation of arteries is impaired and the level of ortho-tyrosine (o-Tyr), an oxidized amino acid is increased. Thus, we hypothesized that elevated vascular level of o-Tyr contributes to the impairment of insulin-induced vascular relaxation. Rats were fed with o-Tyr for 4 weeks. Insulin-induced vasomotor responses of isolated femoral artery were studied using wire myography. Vascular o-Tyr content was measured by HPLC, whereas immunoblot analyses were preformed to detect eNOS phosphorylation. Sustained oral supplementation of rats with o-Tyr increased the content of o-Tyr in the arterial wall and significantly reduced the relaxations to insulin. Sustained supplementation of cultured endothelial cells with o-Tyr increased the incorporation of o-Tyr and mitigated eNOS Ser (1 177) phosphorylation to insulin. Increasing arterial wall o-Tyr level attenuates insulin-induced relaxation - at least in part - by decreasing eNOS activation. Elevated level of o-Tyr could be an underlying mechanism for vasomotor dysfunction in diabetes mellitus.


Assuntos
Endotélio Vascular/metabolismo , Artéria Femoral/fisiologia , Insulina/farmacologia , Tirosina/metabolismo , Vasodilatação/efeitos dos fármacos , Administração Oral , Animais , Células Cultivadas , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Endotélio Vascular/efeitos dos fármacos , Artéria Femoral/efeitos dos fármacos , Técnicas In Vitro , Masculino , Camundongos , Óxido Nítrico Sintase Tipo III/metabolismo , Fosforilação/efeitos dos fármacos , Ratos Sprague-Dawley
8.
Int J Immunopathol Pharmacol ; 26(3): 611-20, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24067458

RESUMO

We evaluated p16INK4A as a reliable option to detect human papilloma virus (HPV) DNA in penile tumor specimens. Formalin-fixed paraffin embedded samples of 26 patients with penile cancer and another 18 cases with non-tumorigenic lesions were stained by three different widely used commercially available chromogenic in-situ hybridization assays high-risk HPV CISH Y1443 (Genpoint, DAKO), pan HPV CISH Y1404 (Genpoint, DAKO), INFORM HPV III (Ventana, Tucson, Arizona) and p16INK4A immunohistochemistry, then compared to the known gold standard polymerase chain reaction detecting HPV 16, 18, 31, and 33. Immunoreactivity for p16INK4A was evaluated by using a 4-tiered (0, 1, 2, and 3) pattern based system. 19 cases were positive for p16INK4A, 13 of which showed a continuous transepithelial staining (pattern 3). Pan HPV ISH showed positivity in 9 cases, high-risk HPV ISH in 7 cases and INFORM HPVIII ISH in 7 cases. p16INK4A IHC pattern 3 versus pattern 0, 1 and 2 exhibited a specificity and positive predictive value of 100 percent, with a sensitivity and negative predictive value of 72 and 62 percent, respectively, which was much better than all HPV in-situ hybridization methods referred to polymerase chain reaction. p16INK4A seems to be a superior marker for the detection of HPV-associated penile squamous cell carcinoma compared to CISH tests, but is not recommend for the detection of non-tumorigenic lesions, where PCR should be used for the initial assessment.


Assuntos
Biomarcadores Tumorais/análise , Carcinoma de Células Escamosas/diagnóstico , Inibidor p16 de Quinase Dependente de Ciclina/análise , DNA Viral/análise , Testes de DNA para Papilomavírus Humano , Imuno-Histoquímica , Hibridização In Situ , Papillomaviridae/genética , Infecções por Papillomavirus/diagnóstico , Neoplasias Penianas/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/química , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/virologia , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Papillomaviridae/classificação , Infecções por Papillomavirus/complicações , Infecções por Papillomavirus/virologia , Neoplasias Penianas/química , Neoplasias Penianas/patologia , Neoplasias Penianas/virologia , Reação em Cadeia da Polimerase , Valor Preditivo dos Testes
9.
Kathmandu Univ Med J (KUMJ) ; 11(41): 81-5, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23774421

RESUMO

Morbus Osler-Weber-Rendu syndrome also known as Hereditary hemorrhagic telangiectasia (HHT) and Meckel's diverticulum is a rare combination disorder. Our case presented with the recurrent obscure gastrointestinal (GI) bleeding for several years. He came with a massive active lower gastrointestinal bleeding. Ultimatively, he underwent an exploratory laparotomy along with intraoperative colonoscopy. A Meckel's diverticulum in combination with multiple erosions was found as a probable cause of the massive gastrointestinal bleeding. An ileo-caeacal resection had been performed and by the pathologist multiple telangiectasias in the resected ileum were established. Blood was sent for genetics and was negative for ENG, ALK-1, and SMAD-4 genes. The patient was discharged after 10 days from time of admission and is under regular follow up without any further bleeding. In this case, despite sophisticated techniques for investigations the cause of the GI-bleeding with several esophagogastroduodenoscopies and colonoscopies, mesenteric angiography and finally an oral double balloon enteroscopy was misdiagnosed till the intra operative endoscopy showed a middle GI-bleeding. The management for obscure GI-bleeding is discussed for countries with lower medical facilities like Nepal in our case with Morbus Osler-Weber-Rendu syndrome.


Assuntos
Hemorragia Gastrointestinal/etiologia , Hemostase Endoscópica/métodos , Divertículo Ileal/complicações , Telangiectasia Hemorrágica Hereditária/complicações , Diagnóstico Diferencial , Endoscopia Gastrointestinal , Hemorragia Gastrointestinal/diagnóstico , Humanos , Masculino , Divertículo Ileal/diagnóstico , Telangiectasia Hemorrágica Hereditária/diagnóstico , Adulto Jovem
10.
Pflege ; 25(5): 353-62, 2012 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-22987468

RESUMO

Unrelieved pain affects up to 75 % of cancer patients. Possible reasons for the undertreatment of pain are, amongst others, patient-related barriers towards cancer pain management. However the way patients decide on the use of analgesics remains unclear. The purpose of this qualitative study was to explore decision-making processes of four women and four men with diverse cancers concerning their pain medications. Audiotaped protocols of the 10-week-intervention and interviews of the PEINCA-pilot study provided data for a secondary analysis. This pilot study was conducted at a comprehensive cancer centre in Germany to test the German version of a cancer pain self-management intervention to enhance oncology patients' pain self-management for the first time. The data of purposively selected patients were analysed using content analysis. The results showed that these patients were very ambivalent about their analgesic use. The need to relieve severe pain conflicted with the desire to avoid opioids at any price. Decisions were reconsidered and overturned even after good experiences with analgesics. This study seems to provide a first look into decision-making processes over 10 weeks during a self-management education. Individually tailored counselling by a professional within the education programme helped the patients adopt new attitudes towards analgesics and gradually reduce their pain levels. Previous experiences of the patients and their possible ambivalence towards analgesics should be considered in a pain therapy, and patients should be coached by professionals.


Assuntos
Assistência Ambulatorial , Analgésicos/administração & dosagem , Cuidadores/educação , Dor Crônica/enfermagem , Tomada de Decisões , Educação em Saúde , Neoplasias/enfermagem , Dor Intratável/tratamento farmacológico , Dor Intratável/enfermagem , Participação do Paciente , Autocuidado , Adulto , Idoso , Analgésicos Opioides/administração & dosagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Medição da Dor/efeitos dos fármacos , Medição da Dor/enfermagem , Educação de Pacientes como Assunto , Projetos Piloto , Autoadministração , Resultado do Tratamento
11.
Orthopade ; 40(5): 425-8, 430-2, 2011 May.
Artigo em Alemão | MEDLINE | ID: mdl-21503717

RESUMO

Charcot neuroarthropathy is one of the most serious manifestations of the diabetic foot syndrome and the multifaceted disease pattern requires interdisciplinary cooperation. Problems may arise even if the diagnosis is made early and lack of pain may mislead to the assumption of an infectious or traumatic event. With respect to operative therapy the characteristics of polyneuropathy and altered bone metabolism have to be taken into account. Rehabilitation, in particular, differs from the guidelines for trauma patients. In the face of high complication risks substantial improvement of function must be the goal for operative treatment.


Assuntos
Artropatia Neurogênica/complicações , Artropatia Neurogênica/cirurgia , Pé Diabético/complicações , Pé Diabético/cirurgia , Osteotomia/efeitos adversos , Procedimentos de Cirurgia Plástica/efeitos adversos , Complicações Pós-Operatórias/etiologia , Humanos , Complicações Pós-Operatórias/diagnóstico
12.
Euro Surveill ; 15(12)2010 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-20350499

RESUMO

This paper reports on several simultaneous outbreaks of norovirus infection linked to the consumption of raw oysters. Since January 2010, 334 cases in 65 clusters were reported from five European countries: the United Kingdom, Norway, France, Sweden and Denmark. The article describes the available epidemiological and microbiological evidence of these outbreaks.


Assuntos
Infecções por Caliciviridae/epidemiologia , Surtos de Doenças/estatística & dados numéricos , Contaminação de Alimentos/estatística & dados numéricos , Doenças Transmitidas por Alimentos/epidemiologia , Gastroenterite/epidemiologia , Norovirus/isolamento & purificação , Ostreidae/microbiologia , Animais , Infecções por Caliciviridae/microbiologia , Europa (Continente)/epidemiologia , Doenças Transmitidas por Alimentos/microbiologia , Gastroenterite/microbiologia , Humanos , Incidência , Vigilância da População , Medição de Risco/métodos , Fatores de Risco
13.
Physiol Int ; 107(3): 444-454, 2020 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-32990654

RESUMO

Within recent years the popularity of sportive activities amongst older people, particularly competitive activities within certain age groups has increased. The purpose of this study was to assess the differences in the cardiorespiratory output at anaerobic threshold and at maximal power, output during an incremental exercise, among senior and young athletes. Ten elderly male subjects [mean (SD) age: 68.45 ± 9.32 years] and eight young male subjects [mean (SD) age: 25.87 ± 5.87 years] performed an incremental exercise test on a treadmill ergometer. No significant differences in body size were evident; however, the differences between the groups for peak power (451.62 ± 49 vs. 172.4 ± 32.2 W), aerobic capacity (57.97 ± 7.5 vs. 40.36 ± 8.6 mL kg-1 min-1), maximal heart rate (190.87 ± 9.2 vs. 158.5 ± 9.1 beats min-1), peak blood lactate (11 ± 1.7 vs. 7.3 ± 1.4 mmol L-1), and % VO2max at ventilatory thresholds (93.18 ± 4.3 vs. 79.29 ± 9.9%) were significantly lower in the senior athletes. The power output at anaerobic threshold was also higher (392 ± 48 vs. 151 ± 23 W) in the young athletes, explaining the significant difference in terms of performance between these groups. We have observed an evident deterioration in some of the cardiovascular parameters; however, the submaximal exercise economy seems to be preserved with aging. Exercise economy (i.e. metabolic cost of sustained submaximal exercise) was not different considerably with age in endurance-trained adults.


Assuntos
Limiar Anaeróbio , Teste de Esforço , Adulto , Idoso , Atletas , Exercício Físico , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio , Resistência Física , Adulto Jovem
14.
J Vasc Res ; 46(5): 397-405, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19155631

RESUMO

BACKGROUND: It has been shown that increases in intraluminal flow elicit dilation in venules, but the mediation of response is not yet clarified. We hypothesized that - in addition to nitric oxide (NO) and dilator prostaglandins (PGI(2)/ PGE(2)) - thromboxane A(2) (TxA(2)) contributes to the mediation of flow-induced responses of venules. METHODS AND RESULTS: Isolated rat gracilis muscle venules (259 +/- 11 microm at 10 mm Hg) dilated as a function of intraluminal flow, which was augmented in the presence of the TxA(2) receptor antagonist SQ 29,548 or the TxA(2) synthase inhibitor ozagrel. In the presence of SQ 29,548, indomethacin or Nomega-nitro-L-arginine methyl-ester decreased flow-induced dilations, whereas in their simultaneous presence dilations were abolished. The selective cyclooxygenase (COX) 1 inhibitor SC 560 reduced, whereas the selective COX-2 inhibitor NS 398 enhanced flow-induced dilations. Immunohistochemistry showed that both COX-1 and COX-2 are present in the wall of venules. CONCLUSION: In skeletal muscle venules, increases in intraluminal flow elicit production of constrictor TxA(2), in addition to the dilator NO and PGI(2)/PGE(2), with an overall effect of limited dilation. These mediators are likely to have important roles in the multiple feedback regulation of wall shear stress in venules during changes in blood flow velocity and/or viscosity.


Assuntos
Ciclo-Oxigenase 1/metabolismo , Ciclo-Oxigenase 2/metabolismo , Músculo Esquelético/irrigação sanguínea , Fluxo Sanguíneo Regional/fisiologia , Tromboxano A2/metabolismo , Animais , Velocidade do Fluxo Sanguíneo/fisiologia , Viscosidade Sanguínea/fisiologia , Compostos Bicíclicos Heterocíclicos com Pontes , Dinoprostona/metabolismo , Inibidores Enzimáticos/farmacologia , Epoprostenol/metabolismo , Ácidos Graxos Insaturados , Hidrazinas/farmacologia , Masculino , Metacrilatos/farmacologia , Músculo Esquelético/fisiologia , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico/metabolismo , Prostaglandina H2/metabolismo , Ratos , Ratos Wistar , Estresse Mecânico , Vênulas/enzimologia
15.
J Cell Biol ; 149(6): 1171-8, 2000 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-10851015

RESUMO

Pex19p is a protein required for the early stages of peroxisome biogenesis, but its precise function and site of action are unknown. We tested the interaction between Pex19p and all known Pichia pastoris Pex proteins by the yeast two-hybrid assay. Pex19p interacted with six of seven known integral peroxisomal membrane proteins (iPMPs), and these interactions were confirmed by coimmunoprecipitation. The interactions were not reduced upon inhibition of new protein synthesis, suggesting that they occur with preexisting, and not newly synthesized, pools of iPMPs. By mapping the domains in six iPMPs that interact with Pex19p and the iPMP sequences responsible for targeting to the peroxisome membrane (mPTSs), we found the majority of these sites do not overlap. Coimmunoprecipitation of Pex19p from fractions that contain peroxisomes or cytosol revealed that the interactions between predominantly cytosolic Pex19p and the iPMPs occur in the organelle pellet that contains peroxisomes. These data, taken together, suggest that Pex19p may have a chaperone-like role at the peroxisome membrane and that it is not the receptor for targeting of iPMPs to the peroxisome.


Assuntos
Proteínas Fúngicas/metabolismo , Proteínas de Membrana/metabolismo , Peroxissomos/metabolismo , Pichia/metabolismo , Sítios de Ligação , Proteínas Fúngicas/genética , Proteínas de Fluorescência Verde , Membranas Intracelulares/metabolismo , Proteínas Luminescentes , Proteínas de Membrana/genética , Testes de Precipitina , Ligação Proteica
16.
J Cell Biol ; 141(3): 625-36, 1998 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-9566964

RESUMO

We used the dye N-(3-triethylammoniumpropyl)-4-(p-diethylaminophenylhexatrienyl ) pyridinium dibromide (FM4-64) and a fusion protein, consisting of the green fluorescent protein appended to the peroxisomal targeting signal, Ser-Lys-Leu (SKL), to label the vacuolar membrane and the peroxisomal matrix, respectively, in living Pichia pastoris cells and followed by fluorescence microscopy the morphological and kinetic intermediates in the vacuolar degradation of peroxisomes by microautophagy and macroautophagy. Structures corresponding to the intermediates were also identified by electron microscopy. The kinetics of appearance and disappearance of these intermediates is consistent with a precursor-product relationship between intermediates, which form the basis of a model for microautophagy. Inhibitors affecting different steps of microautophagy did not impair peroxisome delivery to the vacuole via macroautophagy, although inhibition of vacuolar proteases affected the final vacuolar degradation of green fluorescent protein (S65T mutant version [GFP])-SKL via both autophagic pathways. P. pastoris mutants defective in peroxisome microautophagy (pag mutants) were isolated and characterized for the presence or absence of the intermediates. These mutants, comprising 6 complementation groups, support the model for microautophagy. Our studies indicate that the microautophagic degradation of peroxisomes proceeds via specific intermediates, whose generation and/or processing is controlled by PAG gene products, and shed light on the poorly understood phenomenon of peroxisome homeostasis.


Assuntos
Autofagia/fisiologia , Microcorpos/metabolismo , Pichia/fisiologia , Adaptação Fisiológica , Androstadienos/farmacologia , Cicloeximida/farmacologia , Etanol/farmacologia , Corantes Fluorescentes , Proteínas de Fluorescência Verde , Membranas Intracelulares , Cinética , Proteínas Luminescentes , Fragmentos de Peptídeos , Fluoreto de Fenilmetilsulfonil/farmacologia , Pichia/efeitos dos fármacos , Pichia/ultraestrutura , Inibidores de Proteases/farmacologia , Inibidores da Síntese de Proteínas/farmacologia , Compostos de Piridínio , Compostos de Amônio Quaternário , Coloração e Rotulagem , Vacúolos , Wortmanina
17.
J Cell Biol ; 146(1): 99-112, 1999 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-10402463

RESUMO

We isolated a Pichia pastoris mutant that was unable to grow on the peroxisome-requiring media, methanol and oleate. Cloning the gene by complementation revealed that the encoded protein, Pex22p, is a new peroxin. A Deltapex22 strain does not grow on methanol or oleate and is unable to import peroxisomal matrix proteins. However, this strain targets peroxisomal membrane proteins to membranes, most likely peroxisomal remnants, detectable by fluorescence and electron microscopy. Pex22p, composed of 187 amino acids, is an integral peroxisomal membrane protein with its NH2 terminus in the matrix and its COOH terminus in the cytosol. It contains a 25-amino acid peroxisome membrane-targeting signal at its NH2 terminus. Pex22p interacts with the ubiquitin-conjugating enzyme Pex4p, a peripheral peroxisomal membrane protein, in vivo, and in a yeast two-hybrid experiment. Pex22p is required for the peroxisomal localization of Pex4p and in strains lacking Pex22p, the Pex4p is cytosolic and unstable. Therefore, Pex22p anchors Pex4p at the peroxisomal membrane. Strains that do not express Pex4p or Pex22p have similar phenotypes and lack Pex5p, suggesting that Pex4p and Pex22p act at the same step in peroxisome biogenesis. The Saccharomyces cerevisiae hypothetical protein, Yaf5p, is the functional homologue of P. pastoris Pex22p.


Assuntos
Proteínas de Transporte/metabolismo , Proteínas Fúngicas , Membranas Intracelulares/metabolismo , Ligases/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Membrana Transportadoras , Microcorpos/metabolismo , Pichia/metabolismo , Ubiquitinas , Sequência de Aminoácidos , Sequência de Bases , Transporte Biológico , Proteínas de Transporte/análise , Proteínas de Transporte/química , Proteínas de Transporte/genética , Clonagem Molecular , Sequência Conservada/genética , Citosol/química , Citosol/metabolismo , Citosol/ultraestrutura , Deleção de Genes , Genes Fúngicos/genética , Genes Fúngicos/fisiologia , Teste de Complementação Genética , Membranas Intracelulares/química , Membranas Intracelulares/enzimologia , Membranas Intracelulares/ultraestrutura , Ligases/genética , Proteínas de Membrana/análise , Proteínas de Membrana/química , Proteínas de Membrana/genética , Metanol/metabolismo , Microcorpos/química , Microcorpos/enzimologia , Microcorpos/ultraestrutura , Dados de Sequência Molecular , Ácido Oleico/metabolismo , Fenótipo , Pichia/citologia , Pichia/genética , Pichia/ultraestrutura , Sinais Direcionadores de Proteínas/genética , Sinais Direcionadores de Proteínas/fisiologia , Proteínas Recombinantes de Fusão/análise , Proteínas Recombinantes de Fusão/biossíntese
18.
Mol Cell Biol ; 14(10): 6597-606, 1994 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7523855

RESUMO

The macrocyclic lactone FK506 exerts immunosuppressive effects on T lymphocytes by interfering with signal transduction leading to T-cell activation and also inhibits the growth of eukaryotic microorganisms, including Saccharomyces cerevisiae. We reported previously that an FK506-sensitive target in S. cerevisiae is required for amino acid import and that overexpression of two new genes, TAT1 and TAT2 (formerly called TAP1 and TAP2), confers resistance to the drug. Here we report that TAT1 and TAT2 encode novel members of the yeast amino acid permease family composed of integral membrane proteins that share 30 to 40% identity. TAT1 is the tyrosine high-affinity transporter, which also mediates low-affinity or low-capacity uptake of tryptophan. TAT2 is the tryptophan high-affinity transporter. FK506 does not reduce the levels of TAT1 and TAT2 transcripts, indicating that the inhibition of amino acid transport by the drug is posttranscriptional.


Assuntos
Sistemas de Transporte de Aminoácidos , Aminoácidos/metabolismo , Exorribonucleases , Genes Fúngicos/genética , Proteínas de Membrana Transportadoras/genética , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Tacrolimo/farmacologia , Transportadores de Cassetes de Ligação de ATP/genética , Sequência de Aminoácidos , Sequência de Bases , Transporte Biológico/genética , Mapeamento Cromossômico , Cromossomos Fúngicos , Resistência Microbiana a Medicamentos/genética , Proteínas Fúngicas/genética , Proteínas de Membrana Transportadoras/metabolismo , Dados de Sequência Molecular , Mutagênese , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Transativadores/genética , Transcrição Gênica , Triptofano/análogos & derivados , Triptofano/metabolismo , Triptofano/farmacologia , Tirosina/metabolismo
19.
Mol Cell Biol ; 13(8): 5010-9, 1993 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-7687745

RESUMO

The immunosuppressants cyclosporin A, FK506, and rapamycin inhibit growth of unicellular eukaryotic microorganisms and also block activation of T lymphocytes from multicellular eukaryotes. In vitro, these compounds bind and inhibit two different types of peptidyl-prolyl cis-trans isomerases. Cyclosporin A binds cyclophilins, whereas FK506 and rapamycin bind FK506-binding proteins (FKBPs). Cyclophilins and FKBPs are ubiquitous, abundant, and targeted to multiple cellular compartments, and they may fold proteins in vivo. Previously, a 12-kDa cytoplasmic FKBP was shown to be only one of at least two FK506-sensitive targets in the yeast Saccharomyces cerevisiae. We find that a second FK506-sensitive target is required for amino acid import. Amino acid-auxotrophic yeast strains (trp1 his4 leu2) are FK506 sensitive, whereas prototrophic strains (TRP1 his4 leu2, trp1 HIS4 leu2, and trp1 his4 LEU2) are FK506 resistant. Amino acids added exogenously to the growth medium mitigate FK506 toxicity. FK506 induces GCN4 expression, which is normally induced by amino acid starvation. FK506 inhibits transport of tryptophan, histidine, and leucine into yeast cells. Lastly, several genes encoding proteins involved in amino acid import or biosynthesis confer FK506 resistance. These findings demonstrate that FK506 inhibits amino acid import in yeast cells, most likely by inhibiting amino acid transporters. Amino acid transporters are integral membrane proteins which import extracellular amino acids and constitute a protein family sharing 30 to 35% identity, including eight invariant prolines. Thus, the second FK506-sensitive target in yeast cells may be a proline isomerase that plays a role in folding amino acid transporters during transit through the secretory pathway.


Assuntos
Aminoácidos/metabolismo , Proteínas Fúngicas/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Tacrolimo/farmacologia , Sequência de Aminoácidos , Transporte Biológico/efeitos dos fármacos , Proteínas de Transporte/metabolismo , Resistência Microbiana a Medicamentos , Proteínas Fúngicas/química , Genes Fúngicos , Dados de Sequência Molecular , Saccharomyces cerevisiae/metabolismo , Alinhamento de Sequência , Proteínas de Ligação a Tacrolimo
20.
Resuscitation ; 73(3): 389-93, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17287061

RESUMO

BACKGROUND: Death due to cardiovascular disease occurs more frequently in prisons than the national average. Due to close surveillance 24 h/day, the ability to reach the patient within 3 min and time consuming access for the EMS crews, it was hypothesised that the deployment of automated external defibrillators (AEDs) might make improvements regarding Call-to-the-First-AED-Prompt (CTP) interval and formed the aim of this study. METHODS: Our investigation was analysed on an intention to treat basis and conducted in a prospective, open and observational design. As the primary outcome, the CTP-intervals were compared to the arrival intervals of the EMS. As a secondary outcome, an analysis of all deceased inmates was described. RESULTS: The average daily population of inmates in Austrian correctional facilities is 7714. During a period of 13 months, 10 instances in which an AED was activated and electrodes attached to a collapsed inmate, were reported. The CTP-interval (median+/-S.D.) was 2.3+/-1.6 S.D. min. It took the EMS 10.0+/-4.3 S.D. min. to arrive at the patient's side. Four out of 10 cases of cardiac arrest occurred due to myocardial infarction. Of 39 deceased inmates, a post mortem examination was completed in 34 cases. In 13 cases, cardiovascular disease was the cause of death. DISCUSSION: The main finding was a four-fold reduction of the CTP-interval. This fact indicates the potential improvements which could be achieved with the deployment of AEDs. Our secondary objective revealed that death due to cardiovascular disease was found in a high proportion and could be considered to be a strong incentive to initiate programmes to counter cardiovascular death in prison.


Assuntos
Morte Súbita Cardíaca/prevenção & controle , Cardioversão Elétrica , Serviços Médicos de Emergência/normas , Prisões , Adulto , Idoso , Áustria , Evolução Fatal , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prisões/normas , Estudos Prospectivos , Fatores de Tempo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA