Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
1.
Nature ; 543(7645): 397-401, 2017 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-28300118

RESUMO

In the cold dark matter cosmology, the baryonic components of galaxies-stars and gas-are thought to be mixed with and embedded in non-baryonic and non-relativistic dark matter, which dominates the total mass of the galaxy and its dark-matter halo. In the local (low-redshift) Universe, the mass of dark matter within a galactic disk increases with disk radius, becoming appreciable and then dominant in the outer, baryonic regions of the disks of star-forming galaxies. This results in rotation velocities of the visible matter within the disk that are constant or increasing with disk radius-a hallmark of the dark-matter model. Comparisons between the dynamical mass, inferred from these velocities in rotational equilibrium, and the sum of the stellar and cold-gas mass at the peak epoch of galaxy formation ten billion years ago, inferred from ancillary data, suggest high baryon fractions in the inner, star-forming regions of the disks. Although this implied baryon fraction may be larger than in the local Universe, the systematic uncertainties (owing to the chosen stellar initial-mass function and the calibration of gas masses) render such comparisons inconclusive in terms of the mass of dark matter. Here we report rotation curves (showing rotation velocity as a function of disk radius) for the outer disks of six massive star-forming galaxies, and find that the rotation velocities are not constant, but decrease with radius. We propose that this trend arises because of a combination of two main factors: first, a large fraction of the massive high-redshift galaxy population was strongly baryon-dominated, with dark matter playing a smaller part than in the local Universe; and second, the large velocity dispersion in high-redshift disks introduces a substantial pressure term that leads to a decrease in rotation velocity with increasing radius. The effect of both factors appears to increase with redshift. Qualitatively, the observations suggest that baryons in the early (high-redshift) Universe efficiently condensed at the centres of dark-matter haloes when gas fractions were high and dark matter was less concentrated.

2.
Environ Pollut ; 218: 931-941, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27554983

RESUMO

Beaches are social-ecological systems that provide several services improving human well-being. However, as one of the major coastal interfaces they are subject to plastic pollution, one of the most significant global environmental threats at present. For the first time for Uruguayan beaches, this study assessed and quantified the accumulation of plastic and microplastic debris on sandy beaches of the major touristic destination Punta del Este during the austral spring of 2013. Aiming to provide valuable information for decision-making, we performed a detailed analysis of plastic debris, their eventual transport pathways to the coast (from land and sea), and the associated persistent pollutants. The results indicated that the smallest size fractions (<20 mm) were the dominant size range, with fragments and resin pellets as types with the highest number of items. PAHs and PCBs were found in plastic debris, and their levels did not differ from baseline values reported for similar locations. The abundance of plastic debris was significantly and positively correlated with both the presence of possible land-based sources (e.g. storm-water drains, beach bars, beach access, car parking, and roads), and dissipative beach conditions. The analysis of coastal currents suggested some potential deposition areas along Punta del Este, and particularly for resin pellets, although modeling was not conclusive. From a local management point of view, the development and use of indices that allow predicting trends in the accumulation of plastic debris would be critically useful. The time dimension (e.g. seasonal) should also be considered for this threat, being crucial for locations such as Uruguay, where the use of beaches increases significantly during the summer. This first diagnosis aims to generate scientific baseline, necessary for improved management of plastic litter on beaches and their watersheds.


Assuntos
Praias/estatística & dados numéricos , Monitoramento Ambiental/métodos , Poluição Ambiental/análise , Recuperação e Remediação Ambiental/economia , Recuperação e Remediação Ambiental/métodos , Plásticos/análise , Resíduos/análise , Ecossistema , Humanos , Bifenilos Policlorados/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Uruguai
3.
Gen Comp Endocrinol ; 176(1): 102-11, 2012 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-22266076

RESUMO

Growth hormone (GH) is the main pituitary hormone involved in somatic growth. In fish, the neuroendocrine control of GH is multifactorial due to the interaction of multiple inhibitors and stimulators. Melanin-concentrating hormone (MCH) is a cyclic peptide involved in skin color regulation of fish. In addition, MCH has been related to the regulation of food intake in both mammals and fish. There is only one report presenting evidences on the GH release stimulation by MCH in mammals in experiments in vitro, but there are no data on non-mammals. In the present work, we report for the first time the sequence of MCH and GH cDNA in Cichlasoma dimerus, a freshwater South American cichlid fish. We detected contacts between MCH fibers and GH cells in the proximal pars distalis region of the pituitary gland by double label confocal immunofluorescence indicating a possible functional relationship. Besides, we found that MCH increased GH transcript levels and stimulated GH release in pituitary cultures. Additionally, C. dimerus exposed to a white background had a greater number of MCH neurons with a larger nuclear area and higher levels of MCH transcript than those fish exposed to a black background. Furthermore, fish reared for 3 months in a white background showed a greater body weight and total length compared to those from black background suggesting that MCH might be related to somatic growth in C. dimerus. Our results report for the first time, that MCH is involved in the regulation of the synthesis and release of GH in vitro in C. dimerus, and probably in the fish growth rate.


Assuntos
Ciclídeos/crescimento & desenvolvimento , Ciclídeos/fisiologia , Hormônio do Crescimento/metabolismo , Hormônios Hipotalâmicos/metabolismo , Melaninas/metabolismo , Hipófise/metabolismo , Hormônios Hipofisários/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Cor , Meio Ambiente , Feminino , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Hormônio do Crescimento/genética , Hormônios Hipotalâmicos/genética , Masculino , Melaninas/genética , Dados de Sequência Molecular , Técnicas de Cultura de Órgãos , Hipófise/crescimento & desenvolvimento , Hormônios Hipofisários/genética
5.
Bone Marrow Transplant ; 45(6): 1047-51, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19881553

RESUMO

Mixed chimerism (MC) and secondary graft failure are frequent events following SCT for thalassemia. There is limited information regarding the outcome of donor lymphocyte infusion (DLI) to prevent rejection, mainly from case reports describing only successful cases. We describe a series of seven children affected by beta-thalassemia treated with escalating doses of DLI for level 2-3 MC (donor<90%) following myeloablative SCT from a matched family donor. The infusions were safe and no acute or chronic GVHD were documented; five patients experienced neutropenia and thrombocytopenia resolving spontaneously. DLI was successful in converting to full donor chimerism two patients stratified in the low-risk class (Pesaro class II). Conversely, for five high-risk patients, DLI was not effective in preventing secondary graft failure. This limited series suggests that escalating doses of DLI are safe in thalassemia patients post myeloablative therapy but efficacy may be jeopardized by rapidly growing anti-donor alloimmunity in high-risk patients. We suggest giving escalating doses of donor T cells to attempt a graft-versus-thalassemia as soon as level 2-3 MC is detected.


Assuntos
Rejeição de Enxerto/prevenção & controle , Transplante de Células-Tronco Hematopoéticas/métodos , Transfusão de Linfócitos/métodos , Talassemia beta/terapia , Adolescente , Criança , Pré-Escolar , Feminino , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Contagem de Linfócitos , Masculino , Agonistas Mieloablativos/uso terapêutico , Quimeras de Transplante , Resultado do Tratamento
6.
Cell Mol Biol (Noisy-le-grand) ; 55(1): 23-8, 2009 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-19267998

RESUMO

The N-methyl-diethyl-aspartate (NMDA) receptor has been reported to play an important role in several acute and chronic neuropathologic syndromes. 5-aminolevulinic acid (ALA) accumulates in acute porphyrias due to a deficiency in the heme biosynthetic pathway. Considering that glutamate uptake inhibition caused by ALA could be one of the reasons conducing to porphyric neuropathy, it was of interest to evaluate the effect of porphyrinogenic agents on NMDA glutamatergic system. To this end receptor levels and apparent affinity (Kd) were analyzed in mice brain cortex and cerebellum. NMDA levels were diminished after chronic Isoflurane anaesthesia in brain cortex. In cerebellum, a diminution was observed after acute Enflurane and Isoflurane and allylisopropylacetamide, while ethanol administration showed a significant increase. ALA administration diminished NMDA levels only in cerebellum. Affinity constant was only reduced in brain cortex after chronic Isoflurane treatment. In conclusion, glutamatergic system appears to be involved in the action of some of the porphyrinogenic drugs studied mainly in cerebellum. Receptors regulation should therefore be considered an important mechanism in the cellular response to specific drugs, with the aim of designing new therapies and elucidating the mechanisms leading to porphyric neuropathy and acute attack triggering.


Assuntos
Porfirinogênios/farmacologia , Ácido Aminolevulínico/farmacologia , Animais , Barbital/farmacologia , Cerebelo/efeitos dos fármacos , Cerebelo/metabolismo , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Enflurano/farmacologia , Etanol/farmacologia , Griseofulvina/farmacologia , Isoflurano/farmacologia , Masculino , Camundongos , Receptores de N-Metil-D-Aspartato/metabolismo
7.
Rev. argent. microbiol ; 37(4): 199-202, oct.-dic. 2005. ilus, tab
Artigo em Espanhol | LILACS | ID: lil-634505

RESUMO

Haemophilus influenzae es reconocido como un agente patógeno responsable de infecciones localizadas y sistémicas. Se han descrito 6 tipos de polisacáridos capsulares antigénicamente distintos (a, b, c, d, e, y f ) que se pueden identificar por aglutinación en lámina con antisueros específicos. También existen cepas no capsuladas (NC) fenotípicamente no tipificables (NT). La introducción de la vacuna conjugada produjo una marcada disminución de las enfermedades invasivas causadas por H. influenzae tipo b. En este contexto, la tipificación capsular mediante PCR es el método más apropiado para distinguir las cepas no capsuladas de las mutantes b deficientes en cápsula (b-) y detectar la presencia de cepas pertenecientes a otros serotipos que no puedan ser tipificables por aglutinación. Se determinó el genotipo capsular a 38 aislamientos de Haemophilus influenzae no tipificables por aglutinación, derivados al servicio de Bacteriología Clínica del INEI-ANLIS "Dr. Carlos G. Malbrán" en el período 2002-2004. El 78,9% de los aislamientos provenían de hemocultivos y la mayor parte de ellos estaban asociados a foco respiratorio. El 100% de los aislamientos fueron identificados como H. influenzae no capsulados mediante la técnica de PCR.


Haemophilus influenzae is recognized as a pathogenic agent responsible of localized and systemic infections. Six antigenically different capsular polysaccharide types have been described (a, b, c, d, e, and f ) which can be identified by slide agglutination with specific antisera. Besides there are non capsulated strains that cannot be typed by slide agglutination. The introduction of the conjugated vaccine produced an important reduction of invasive diseases caused by H. influenzae type b. Capsular typing by PCR is the most appropriated method for distinguishing non capsulated strains from capsule deficient type b mutants (b-) and for detecting strains of other serotypes that cannot be detected by slide agglutination. Capsular genotype was studied in 38 isolates of non-typeable Haemophilus influenzae received at INEIANLIS "Dr. Carlos G. Malbrán" between 2002-2004. Of the isolates included in this study 78.9% of them were recovered from blood cultures and most of them were associated with a respiratory focus. By PCR technique 100% of the isolates were identified as non-capsulate H. influenzae and genotype b-was not detected.


Assuntos
Humanos , Lactente , Cápsulas Bacterianas/análise , Técnicas de Tipagem Bacteriana/métodos , Infecções por Haemophilus/microbiologia , Haemophilus influenzae/classificação , Reação em Cadeia da Polimerase/métodos , Testes de Aglutinação , Bacteriemia/microbiologia , Cápsulas Bacterianas/genética , Cápsulas Bacterianas/imunologia , Líquidos Corporais/microbiologia , DNA Bacteriano/análise , DNA Bacteriano/genética , Haemophilus influenzae/genética , Haemophilus influenzae/imunologia , Haemophilus influenzae/isolamento & purificação , Infecções Respiratórias/microbiologia
8.
Rev Argent Microbiol ; 37(4): 199-202, 2005.
Artigo em Espanhol | MEDLINE | ID: mdl-16502640

RESUMO

Haemophilus influenzae is recognized as a pathogenic agent responsible of localized and systemic infections. Six antigenically different capsular polysaccharide types have been described (a, b, c, d, e, and f ) which can be identified by slide agglutination with specific antisera. Besides there are non capsulated strains that cannot be typed by slide agglutination. The introduction of the conjugated vaccine produced an important reduction of invasive diseases caused by H. influenzae type b. Capsular typing by PCR is the most appropriated method for distinguishing non capsulated strains from capsule deficient type b mutants (b-) and for detecting strains of other serotypes that cannot be detected by slide agglutination. Capsular genotype was studied in 38 isolates of non-typeable Haemophilus influenzae received at INE-ANLIS "Dr. Carlos G. Malbrán" between 2002-2004. Of the isolates included in this study 78.9% of them were recovered from blood cultures and most of them were associated with a respiratory focus. By PCR technique 100% of the isolates were identified as non-capsulate H. influenzae and genotype b-was not detected.


Assuntos
Cápsulas Bacterianas/análise , Técnicas de Tipagem Bacteriana/métodos , Infecções por Haemophilus/microbiologia , Haemophilus influenzae/classificação , Reação em Cadeia da Polimerase/métodos , Testes de Aglutinação , Bacteriemia/microbiologia , Cápsulas Bacterianas/genética , Cápsulas Bacterianas/imunologia , Líquidos Corporais/microbiologia , DNA Bacteriano/análise , DNA Bacteriano/genética , Haemophilus influenzae/genética , Haemophilus influenzae/imunologia , Haemophilus influenzae/isolamento & purificação , Humanos , Lactente , Infecções Respiratórias/microbiologia
9.
Eat Weight Disord ; 9(2): 134-8, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15330081

RESUMO

An important problem with obese patients suffering from binge eating disorders (BED) is to treat their dysfunctional eating patterns while initiating a weight loss. We propose to assess a cognitive-behavioral therapy combined with a nutritional and a physical activity program. Our purpose is to verify that the addition of a nutritional and a physical program leads to a significant weight loss and enables psychological improvement. The patients (n=61) participated in a 12 weekly sessions group treatment of either a purely cognitive-behavioral therapy, or a cognitive-behavioral therapy associated to a nutritional approach mainly focused on fat restriction, or to a cognitive-behavioral therapy combined with a nutritional and a physical activity approach. The mean weight loss is significant (p<0.01) after the association of the cognitive-behavioral therapy and the nutritional education, but is even more significant (p<0.001) after the combination of a cognitive-behavioral therapy with a nutritional education and a physical activity program. Depression scores decrease in the three approaches, anxiety (p<0.05) results improve only in the combined nutritional, physical activity and cognitive-behavioral approach. Eating disorders improved significantly in all three approaches even if improvements in subscales seem more important in the combined approach. Finally, exercise seems to be a positive addition to the nutritional cognitive-behavioral therapy since it decreases negative mood, improves eating disorders and leads to an effective body weight loss.


Assuntos
Bulimia/terapia , Terapia Cognitivo-Comportamental/métodos , Educação em Saúde , Atividade Motora , Fenômenos Fisiológicos da Nutrição , Obesidade/terapia , Adulto , Índice de Massa Corporal , Bulimia/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/diagnóstico , Inquéritos e Questionários , Redução de Peso
11.
Diabetes Metab ; 27(1): 71-7, 2001 Feb.
Artigo em Francês | MEDLINE | ID: mdl-11240451

RESUMO

We present a description of basic concepts of the cognitive-behavioural approach in obese patients with binge eating disorders. In the first place, we propose the process leading to a behavioural reorganization. Then, we evoke some components of the cognitive restructuring that allow to understand the link between an event and binge eating disorders. We also give practical advice to the health care providers.


Assuntos
Bulimia/psicologia , Bulimia/terapia , Terapia Cognitivo-Comportamental , Obesidade/psicologia , Obesidade/terapia , Cognição , Comportamento Alimentar , Humanos
12.
Patient Educ Couns ; 42(1): 47-52, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11080605

RESUMO

The most important problem in cognitive-behavioural therapies for obese patients is to initiate weight loss without reinforcing the eating-behavioural disorders. We propose to assess the cognitive-behavioural therapy in obese patients suffering from eating disorders with and without combining a nutritional approach based on fat information. The patients (n = 60) have followed a group treatment of 12 weekly cognitive-behavioural therapy sessions with or without a combined nutritional approach mainly focused on fat restriction. The scores for depression (P < 0.01), anxiety (P < 0.01) and eating disorders (P < 0.001) are significantly and similarly improved with both types of treatments. The mean weight loss is significant (P < 0.001) only after a combined nutritional cognitive-behavioural approach. The Eating Disorders Inventory (EDI) subgroup 'Drive for thinness' remains only in a combined therapy (ANOVA P < 0.01), which could explain the weight loss that only occurs in this group. Finally, the association between a cognitive-behavioural therapy and a nutritional learning process improves the anxiety and depression related to eating disorders as well as the weight loss.


Assuntos
Terapia Cognitivo-Comportamental , Transtornos da Alimentação e da Ingestão de Alimentos/psicologia , Transtornos da Alimentação e da Ingestão de Alimentos/terapia , Obesidade/psicologia , Obesidade/terapia , Adulto , Análise de Variância , Gorduras na Dieta/administração & dosagem , Comportamento Alimentar , Feminino , Humanos , Escalas de Graduação Psiquiátrica , Resultado do Tratamento
13.
Dig Liver Dis ; 33(9): 785-7, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11838614

RESUMO

A case of Cronkhite-Canada syndrome is described. Few cases have been published and in most patients the prognosis is poor. A variety of medical measures have been attempted in those in whom remission has been reported. In the patient presented here, a sustained partial-remission has been achieved with steroids.


Assuntos
Anti-Inflamatórios/uso terapêutico , Pólipos Intestinais/tratamento farmacológico , Prednisona/uso terapêutico , Humanos , Pólipos Intestinais/diagnóstico , Masculino , Pessoa de Meia-Idade
14.
Hepatology ; 27(3): 853-6, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9500717

RESUMO

Most patients with serum hepatitis C virus (HCV) RNA and persistently normal alanine transaminase (ALT) levels show histological features of mild to moderately active chronic hepatitis. Some cirrhosis has also been reported. To assess whether interferon (IFN) treatment led to long-term HCV suppression in these patients, 31 previously untreated patients (15 men, 16 women; mean age, 44 years) with serum HCV RNA, persistently normal ALT levels on at least four consecutive occasions 2 months apart, and histological features of chronic hepatitis (21 mild activity, 10 moderate activity) were randomized to receive 1FN-alpha-2a, 3 MU three times a week for 6 months (n = 16), or no treatment (n = 15). All patients were followed up for at least 6 months after treatment ended. HCV RNA was tested by nested reverse-transcription polymerase chain reaction (RT-PCR) using 5'-untranslated region complementary primers, quantified by branched-DNA assay, and typed by nested RT-PCR testing for the HCV core region. Treated and untreated patients had similar epidemiological, virological, and histological characteristics. At the end of treatment, serum HCV RNA was still detected in 15 patients (94%) and 14 controls (93%). ALT levels flared up in 10 patients receiving IFN (62%) and in 1 control (62% vs. 7%; P < .005, chi2 test). In conclusion, 6 months' treatment with IFN-alpha-2a did not eradicate HCV RNA from serum in carriers with persistently normal ALT levels but caused ALT flare-ups in two thirds of them. Until more is known about the natural history of HCV RNA carriers with normal ALT levels, these patients should not be treated with IFN.


Assuntos
Alanina Transaminase/sangue , Portador Sadio/terapia , Hepatite C/terapia , Interferon-alfa/uso terapêutico , RNA Viral/análise , Adulto , Feminino , Humanos , Interferon alfa-2 , Interferon-alfa/efeitos adversos , Fígado/patologia , Masculino , Pessoa de Meia-Idade , Proteínas Recombinantes
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA