Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Environ Res ; 244: 117827, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38072112

RESUMO

Chemical pollution is a global concern as contaminants are transported and reach even the remote regions of Antarctica. Seabirds serve as important sentinels of pollution due to their high trophic position and wide distribution. This study examines the influence of migration and trophic ecology on the exposure of two Antarctic seabirds, Wilson's storm petrel (Oceanites oceanicus - Ooc), and Cape petrel (Daption capense - Dca), to chemical elements and perfluoroalkyl substances (PFAS). Our methodology involved assessing the concentration of these pollutants in feather samples obtained from carcasses, offering a practical means for monitoring contamination. Trace and major element concentrations were comparable in both species, suggesting that migratory patterns have a minimal impact on exposure levels. However, Ooc had higher concentration of PFAS compared to Dca (mean, ng g-1dry weight, PFOA: Ooc:0.710, Dca:0.170; PFTrDA: Ooc:0.550, Dca:0.360, and PFTeDA: Ooc:1.01, Dca:0.190), indicating that migration to the more polluted Northern Hemisphere significantly affects PFAS exposure. Furthermore, while no strong associations were found between either trace elements or PFAS and the three stable isotopes (δ13C, δ15N, and δ34S), a negative association was observed between PFUnDA and δ15N, hinting at potential biodilution. The research concludes that the migratory patterns of these seabird species affect their PFAS exposure, underscoring the critical need for further exploration and understanding of these relationships to better inform conservation strategies.


Assuntos
Fluorocarbonos , Oligoelementos , Animais , Regiões Antárticas , Aves , Ecologia , Estado Nutricional , Fluorocarbonos/toxicidade , Monitoramento Ambiental
2.
Chemosphere ; 340: 139871, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37611760

RESUMO

Although naturally present in the environment, mercury (Hg) input is significantly amplified by anthropogenic activities on a global scale, leading to a growing concern about the recent increase in Hg levels observed in Antarctica. This study investigated total mercury (THg) concentrations in feathers and eggs of resident and migratory Antarctic seabirds. Stable isotope data (δ15N, δ13C, and δ34S) were employed to ascertain the key factors influencing the exposure of these species to Hg. We gathered feathers and eggs from three resident species - Adélie, Gentoo, and Chinstrap penguins, as well as five migratory species - Snowy Sheathbill, Antarctic Tern, Southern Giant Petrel, Kelp Gull, and South Polar Skua. These samples were collected from Admiralty Bay, King George Island, in the Antarctica Peninsula. For all species, THg concentrations were higher in feathers (mean ± SD: 2267 ± 2480 ng g-1 dw) than in eggs (906 ± 1461 ng g-1 dw). Species occupying higher trophic positions, such as the Southern Giant Petrel (5667 ± 1500 ng g-1 dw) and South Polar Skua (4216 ± 1101 ng. g-1 dw), exhibited higher THg levels in their feathers than those at lower positions, like Antarctic Tern (1254 ± 400 ng g-1 dw) and Chinstrap Penguin (910 ± 364 ng g-1 dw). The δ15N values, which serve as a proxy for the trophic position, significantly correlated with THg concentrations. These findings reveal that trophic position influences THg concentrations in Antarctic seabirds. Migration did not appear to significantly affect the exposure of seabirds to THg, contrary to initial expectations. This research highlights the importance of evaluating the impacts of THg contamination on the Antarctic ecosystem by considering a variety of species. This multi-species approach offers critical insights into the factors that may potentially influence the exposure of these species to contaminants.


Assuntos
Charadriiformes , Mercúrio , Spheniscidae , Animais , Regiões Antárticas , Ecossistema , Efeitos Antropogênicos
3.
J Physiol Pharmacol ; 69(6)2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30802218

RESUMO

Recently, the proteomic analysis has become an ideal tool to study the structure and function of platelets. We proposed a nano-liquid chromatography (nano-LC) technique coupled off-line with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF-MS) for rat platelet proteome analysis. In this study, we attempted to analyze the rat platelet proteome in two different subcellular fractions: cytosol and membrane. Platelet-rich plasma was collected from healthy rats. The platelet samples were extracted with Subcellular Proteome Extraction Kit to collect subcellular compartments. For further investigations, platelet lysate, cytosol and membrane fractions were used. Enzymatic digestion of proteins was performed using Filter Aided Sample Preparation method with trypsin as a proteolytic enzyme. Tryptic peptides were analyzed using nano-LC-MALDI-TOF/TOF-MS. Platelet proteins identification was performed using the Mascot engine. We identified 238 proteins in the platelet lysate, 210 in the cytosol, and 148 in the membrane fraction. Among them, 45 were unique for platelet lysate, 55 for cytosol, and 34 for the membrane fraction. The gene ontology analysis showed that there were differences in the proteome of cytosol and membrane fractions related to the molecular functions, i.e. coagulative activity. Our results may suggest that the membrane or cytosol location of the proteins with coagulative activity may be responsible for the acute or delayed platelet response to an agonist. The nano-LC-MALDI-TOF/TOF-MS method can be used for identifying proteins of subcellular fraction in rat platelets.


Assuntos
Plaquetas/metabolismo , Cromatografia Líquida/métodos , Proteoma/metabolismo , Proteômica/métodos , Animais , Membrana Celular/metabolismo , Citosol/metabolismo , Masculino , Peptídeos/metabolismo , Ratos , Ratos Wistar , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Frações Subcelulares/metabolismo
4.
J Adv Model Earth Syst ; 9(7): 2526-2544, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-29399268

RESUMO

A new paradigm of simulating suspended sediment load (SSL) with a Land Surface Model (LSM) is presented here. Five erosion and SSL algorithms were applied within a common LSM framework to quantify uncertainties and evaluate predictability in two steep, forested catchments (>1,000 km2). The algorithms were chosen from among widely used sediment models, including empirically based: monovariate rating curve (MRC) and the Modified Universal Soil Loss Equation (MUSLE); stochastically based: the Load Estimator (LOADEST); conceptually based: the Hydrologic Simulation Program-Fortran (HSPF); and physically based: the Distributed Hydrology Soil Vegetation Model (DHSVM). The algorithms were driven by the hydrologic fluxes and meteorological inputs generated from the Variable Infiltration Capacity (VIC) LSM. A multiobjective calibration was applied to each algorithm and optimized parameter sets were validated over an excluded period, as well as in a transfer experiment to a nearby catchment to explore parameter robustness. Algorithm performance showed consistent decreases when parameter sets were applied to periods with greatly differing SSL variability relative to the calibration period. Of interest was a joint calibration of all sediment algorithm and streamflow parameters simultaneously, from which trade-offs between streamflow performance and partitioning of runoff and base flow to optimize SSL timing were noted, decreasing the flexibility and robustness of the streamflow to adapt to different time periods. Parameter transferability to another catchment was most successful in more process-oriented algorithms, the HSPF and the DHSVM. This first-of-its-kind multialgorithm sediment scheme offers a unique capability to portray acute episodic loading while quantifying trade-offs and uncertainties across a range of algorithm structures.

5.
J Appl Physiol (1985) ; 91(1): 408-16, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11408458

RESUMO

Nonobstructive (i.e., central) sleep apnea is a major cause of sleep-disordered breathing in patients with stable congestive heart failure (CHF). Although central sleep apnea (CSA) is prevalent in this population, occurring in 40-50% of patients, its pathogenesis is poorly understood. Dynamic loop gain and delay of the chemoreflex response to CO(2) was measured during wakefulness in CHF patients with and without CSA by use of a pseudorandom binary CO(2) stimulus method. Use of a hyperoxic background minimized responses derived from peripheral chemoreceptors. The closed-loop and open-loop gain, estimated from the impulse response, was three times greater in patients with nocturnal CSA (n = 9) than in non-CSA patients (n = 9). Loop dynamics, estimated by the 95% response duration time, did not differ between the two groups of patients. We speculate that an increase in dynamic gain of the central chemoreflex response to CO(2) contributes to the genesis of CSA in patients with CHF.


Assuntos
Dióxido de Carbono/fisiologia , Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/fisiopatologia , Respiração/efeitos dos fármacos , Síndromes da Apneia do Sono/etiologia , Idoso , Células Quimiorreceptoras/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Reflexo/fisiologia
6.
Urol Int ; 66(3): 164-5, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11316982

RESUMO

An enterovesical fistula due to an intestinal foreign body is presented and the therapeutic aspects of the lesion are discussed.


Assuntos
Corpos Estranhos/complicações , Doenças do Íleo/etiologia , Fístula Intestinal/etiologia , Fístula da Bexiga Urinária/etiologia , Feminino , Humanos , Pessoa de Meia-Idade
8.
Ginekol Pol ; 66(11): 618-25, 1995 Nov.
Artigo em Polonês | MEDLINE | ID: mdl-8698252

RESUMO

In 99 newborns with hypoxic-ischemic encephalopathy (22 with mild, 53 with moderate and 24 with severe stage) correlation between birth weight, low Apgar score, high-risk pregnancy and delivery and stage of encephalopathy and results of the treatment was made. Low Apgar score (< 3) had significantly influence on the development of severe encephalopathy. Most important perinatal risk factor was abnormal delivery. Especially high mortality because of moderate and severe stage of encephalopathy in prematures with intracranial hemorrhage and congenital infection was noted. Full-term babies died because of others causes. It was shown, that unfavourable outcome of neonatal encephalopathy depends mainly on high-risk delivery.


Assuntos
Hipóxia Encefálica/terapia , Índice de Apgar , Parto Obstétrico/efeitos adversos , Feminino , Humanos , Hipóxia Encefálica/etiologia , Hipóxia Encefálica/mortalidade , Recém-Nascido , Doenças do Prematuro/mortalidade , Masculino , Gravidez , Fatores de Risco , Taxa de Sobrevida , Resultado do Tratamento
9.
J Craniomaxillofac Surg ; 22(3): 167-76, 1994 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8063910

RESUMO

Combined treatment by continuous intravenous infusion of a selected antibiotic and heparin and/or streptokinase was elaborated as a method of causal, systemic treatment of bacterial osteomyelitis. The aim of the combined treatment was to overcome infection and disturbances in the coagulation and fibrinolysis system which lead to impairment of the bone blood supply and its subsequent necrosis as the main factor in the aetiopathology of osteomyelitis. Between 1969 and 1991, combined treatment was introduced in 63 patients with acute onset disease or with chronic osteomyelitis. Osteomyelitis was located in the mandible in 38 patients and in the long bones in 14 patients. Prior to combined treatment, moderate bone surgery was performed in 21 patients, while 31 patients were excluded from surgery. Combined treatment with an antibiotic and heparin (A+H) was performed in 43 patients, and the other 6 patients had infusion of an antibiotic, streptokinase and heparin (A+S+H). The authors' method of combined treatment offers a new approach and an alternative to routinely-ordered antibiotic therapy and radical surgery, which allow frequent recurrences of the disease, a long-lasting course and severe complications.


Assuntos
Antibacterianos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Heparina/uso terapêutico , Doenças Mandibulares/tratamento farmacológico , Doenças Mandibulares/microbiologia , Osteomielite/tratamento farmacológico , Osteomielite/microbiologia , Estreptoquinase/uso terapêutico , Adolescente , Adulto , Idoso , Ampicilina/administração & dosagem , Ampicilina/uso terapêutico , Antibacterianos/administração & dosagem , Infecções Bacterianas/cirurgia , Terapia Combinada , Combinação de Medicamentos , Feminino , Seguimentos , Gentamicinas/administração & dosagem , Gentamicinas/uso terapêutico , Heparina/administração & dosagem , Humanos , Lincomicina/administração & dosagem , Lincomicina/uso terapêutico , Masculino , Doenças Mandibulares/cirurgia , Meticilina/administração & dosagem , Meticilina/uso terapêutico , Pessoa de Meia-Idade , Osteomielite/cirurgia , Penicilinas/administração & dosagem , Penicilinas/uso terapêutico , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/cirurgia , Estreptoquinase/administração & dosagem
12.
Ophthalmology ; 88(7): 624-9, 1981 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7267030

RESUMO

A computer program designed according to the needs of clinical investigators has recently been implemented. This ambitious undertaking allows the ophthalmologist direct interfacing and control over all his data, presently 3,252 diabetic patient records, and thus harnesses his hypothesis-testing intuitions with the memory, speed, and flexibility of modern-day computers. There are three program modes: QUERY, a disease-independent language by which the clinician selects his population; SELECT, the actual computer selection, and DISPLAY: where general statistical maneuvers, relationships among disease parameters, ancillary data compilations, and printouts are performed. Being computer-independent and disease-independent, and adaptable to most needs of clinical investigators, this computer program brings a refreshingly new approach to the study of disease.


Assuntos
Retinopatia Diabética/diagnóstico , Sistemas de Informação , Humanos
14.
Artigo em Inglês | MEDLINE | ID: mdl-6162762

RESUMO

Hale's colloidal iron reaction for acid mucopolysaccharides was applied to semithin sections of Epon-embedded tissues routinely processed for electron microscopy. The reaction was found to be positive only after partial removal of the resin in NaOH/absolute ethanol solution; its sensitivity, however, did not reach that obtained in paraffin or frozen sections. The duration of the Epon-removing procedure seems to be crucial for the specificity of staining.


Assuntos
Secções Congeladas , Glicosaminoglicanos/análise , Ferro , Microtomia , Animais , Anuros , Cartilagem/citologia , Coloides , Resinas Epóxi , Intestino Delgado/citologia , Rim/citologia , Fígado/citologia , Métodos , Camundongos , Hipófise/citologia , Coelhos , Ratos , Coloração e Rotulagem/métodos , Glândula Submandibular/citologia , Traqueia/citologia
15.
Z Mikrosk Anat Forsch ; 94(6): 1090-104, 1980.
Artigo em Inglês | MEDLINE | ID: mdl-6269309

RESUMO

The percentage of cell populations of hypophysis pars distalis, their ultrastructure, degranulation phenomena and volume of cell nuclei easured by karyometry was examined in frogs, Rana esculenta L. irradiated by UV light. The observed changes, reflecting alterations of the secretory activity were most prominent in B2 cells producing gonadotropic hormones and in B3 cells probably responsible for the secretion of ACTH. A concomitant increase of the number of chromophobic cells was observed. The obtained results are discussed in relation to data from the existing literature.


Assuntos
Hipófise/efeitos da radiação , Rana esculenta/anatomia & histologia , Raios Ultravioleta , Hormônio Adrenocorticotrópico/metabolismo , Animais , Feminino , Microscopia Eletrônica , Hipófise/metabolismo , Rana esculenta/metabolismo
16.
Acta Histochem ; 55(1): 98-103, 1976.
Artigo em Inglês | MEDLINE | ID: mdl-58538

RESUMO

Different results of PAS reaction performed on semithin sections of Epon-embedded tissues were obtained when the sections were exposed for various time intervals to saturated solution of NaOH in absolute ethanol, the reagent known to dissolve the resin and facilitate staining. In the untreated sections only glycogen revealed strong PAS reaction, most mucosubstances reacted weakly or not at all. After 1 to 5 min of NaOH in absolute ethanol treatment results observed were in accordance with those usually seen in paraffin sections. When, however, the time of Epon-dissolving procedure was longer than 10 min, most tissue structures demonstrated positive, largely diffuse staining. The mechanism of the observed effect and its significance for the application of PAS reaction to Epon sections are discussed.


Assuntos
Ácido Periódico , Bases de Schiff , Coloração e Rotulagem , Animais , Colágeno/análise , Resinas Epóxi , Etanol , Humanos , Glicogênio Hepático/análise , Mucoproteínas/análise , Muco/análise , Hidróxido de Sódio
17.
Acta Histochem ; 52(1): 17-22, 1975.
Artigo em Inglês | MEDLINE | ID: mdl-52269

RESUMO

Light microscopic histochemical methods for differential staining of adenohypophysis glandular cells were applied to Epon-embedded tissue, after prior softening of resin with saturated solution of NaOH in absolute ethanol. All investigated staining procedures, i.e. carmoisin L-orange G, PAS-orange G, PAS-range G-methyl blue, Gabe's aldehyde fuchsin-Halmi counterstain, aldehyde thionin-PAS-orange G and performic acid-alcian blue-PAS-orange G were found to give satisfactory results and tissue structure showed no signs of damage caused by the Epon-dissolving reagent. The features of light microscopic image given by plastic-embedded semithin sections: nearly 2-dimensional picture as well as the highest possible resolving power provide the opportunity for much more precise and detailed examination of adenohypophysis prepared that way, as compared with conventionally paraffin-embedded gland. Moreover, the described technique permits to establish a direct connection between light microscopic differential histochemistry of adenohypophysis and the electron microscopy by means of adjacent sections.


Assuntos
Adeno-Hipófise/análise , Hipófise/análise , Coloração e Rotulagem/métodos , Animais , Grânulos Citoplasmáticos/análise , Resinas Epóxi , Feminino , Histocitoquímica , Parafina , Adeno-Hipófise/metabolismo , Rana esculenta , Hidróxido de Sódio , Solventes
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...