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1.
J Exp Biol ; 217(Pt 14): 2499-508, 2014 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-24803457

RESUMO

The distribution patterns of many species in the intertidal zone are partly determined by their ability to survive and recover from tidal emersion. During emersion, most crustaceans experience gill collapse, impairing gas exchange. Such collapse generates a state of hypoxemia and a hypercapnia-induced respiratory acidosis, leading to hyperlactaemia and metabolic acidosis. However, how such physiological responses to emersion are modified by prior exposure to elevated CO2 and temperature combinations, indicative of future climate change scenarios, is not known. We therefore investigated key physiological responses of velvet swimming crabs, Necora puber, kept for 14 days at one of four pCO2/temperature treatments (400 µatm/10°C, 1000 µatm/10°C, 400 µatm/15°C or 1000 µatm/15°C) to experimental emersion and recovery. Pre-exposure to elevated pCO2 and temperature increased pre-emersion bicarbonate ion concentrations [HCO3(-)], increasing resistance to short periods of emersion (90 min). However, there was still a significant acidosis following 180 min emersion in all treatments. The recovery of extracellular acid-base via the removal of extracellular pCO2 and lactate after emersion was significantly retarded by exposure to both elevated temperature and pCO2. If elevated environmental pCO2 and temperature lead to slower recovery after emersion, then some predominantly subtidal species that also inhabit the low to mid shore, such as N. puber, may have a reduced physiological capacity to retain their presence in the low intertidal zone, ultimately affecting their bathymetric range of distribution, as well as the structure and diversity of intertidal assemblages.


Assuntos
Braquiúros/metabolismo , Dióxido de Carbono/metabolismo , Temperatura Alta/efeitos adversos , Água do Mar/química , Acidose , Animais , Mudança Climática , Concentração de Íons de Hidrogênio , Hipercapnia , Ondas de Maré
2.
Integr Comp Biol ; 53(4): 660-70, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23660590

RESUMO

The injection of anthropogenically-produced CO2 into the atmosphere will lead to an increase in temperature and a decrease in pH at the surface of the oceans by 2100. Marine intertidal organisms possess the ability to cope in the short term with environmental fluctuations exceeding predicted values. However, how they will cope with chronic exposure to elevated temperature and pCO2 is virtually unknown. In addition, individuals from the same species/population often show remarkable levels of variation in their responses to complex climatic changes: in particular, variation in metabolic rates often is linked to differences in individuals' performances and fitness. Despite its ecological and evolutionary importance, inter-individual variation has rarely been investigated within the context of climatic changes, and most investigations have typically employed orthogonal experimental designs paired to analyses of independent samples. Although this is undoubtedly a powerful and useful approach, it may not be the most appropriate for understanding all alterations of biological functions in response to environmental changes. An individual approach arguably should be favored when trying to describe organisms' responses to climatic change. Consequently, to test which approach had the greater power to discriminate the intensity and direction of an organism's response to complex climatic changes, we investigated the extracellular osmo/iono-regulatory abilities, upper thermal tolerances (UTTs), and metabolic rates of individual adults of an intertidal amphipod, Echinogammarus marinus, exposed for 15 days to combined elevated temperature and pCO2. The individual approach led to stronger and different predictions on how ectotherms will likely respond to ongoing complex climatic change, compared with the independent approaches. Consequently, this may call into question the relevance, or even the validity, of some of the predictions made to date. Finally, we argue that treating individual differences as biologically meaningful can lead to a better understanding of the physiological responses themselves and the selective processes that will occur with complex climatic changes; selection will likely play a crucial role in defining species' responses to future environmental changes. Individuals with higher metabolic rates were also characterized by greater extracellular osmo/iono-regulative abilities and higher UTTs, and thus there appeared to be no evolutionary trade-offs between these functions. However, as individuals with greater metabolic rates also have greater costs for maintenance and repair, and likely a lower fraction of energy available for growth and reproduction, trade-offs between life-history and physiological performance may still arise.


Assuntos
Aclimatação/fisiologia , Anfípodes/fisiologia , Mudança Climática , Estuários , Osmorregulação/fisiologia , Estresse Fisiológico/fisiologia , Análise de Variância , Animais , Dióxido de Carbono/análise , Metabolismo Energético/fisiologia , Inglaterra , Concentração de Íons de Hidrogênio , Masculino , Oceanos e Mares , ATPase Trocadora de Sódio-Potássio/metabolismo , Temperatura
3.
Br J Plast Surg ; 42(4): 429-34, 1989 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-2765736

RESUMO

In this study the efficacy of preserving microvascular heterografts with glutaraldehyde tanning was investigated. These were compared with glutaraldehyde-tanned autografts. Previous studies have found that untreated autograft veins maintain a 95% patency rate, whilst untreated heterograft veins (Group 1) had a 15% patency rate at 4 weeks in this study. Autogenous glutaraldehyde-tanned rabbit carotid arterial grafts (Group 2) and glutaraldehyde-tanned human chorionic veins (Group 3) were interposed in rabbit femoral or carotid arteries. Fifty per cent and 75% patency rates were achieved respectively at 4 weeks. The low patency rate of the autogenous group suggests that the glutaraldehyde tanning technique itself is largely responsible for the low patency of glutaraldehyde-tanned human chorionic veins rather than any immunological response. Therefore if human chorionic veins are to be used as a readily available preserved microvascular graft, further investigation is required to develop another technique which will reduce antigenicity without promoting thrombosis.


Assuntos
Bioprótese , Artérias Carótidas , Córion/irrigação sanguínea , Animais , Artérias Carótidas/cirurgia , Artéria Femoral/cirurgia , Humanos , Métodos , Coelhos , Grau de Desobstrução Vascular , Veias
4.
Plast Reconstr Surg ; 71(1): 98-106, 1983 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-6849028

RESUMO

The healing of microvenous grafts to femoral arteries in the rabbit has been studied using scanning electron microscopy at intervals ranging from zero time to 5 months. Healing of the grafts followed a similar pattern to that of end-to-end repairs. Postoperative survival of the original endothelium was far superior in the vein than in the artery. Re-endothelialization was completed by 2 weeks. No dilation of the graft or aneurysm formation appeared. A detailed account of the healing vein grafts has been reported and will enable comparison of healing of microvascular heterografts.


Assuntos
Artérias/cirurgia , Microcirurgia , Veias/cirurgia , Animais , Artérias/patologia , Endotélio/irrigação sanguínea , Endotélio/patologia , Endotélio/cirurgia , Microscopia Eletrônica de Varredura , Coelhos , Retalhos Cirúrgicos , Fatores de Tempo , Veias/patologia , Cicatrização
5.
Br J Plast Surg ; 33(3): 365-70, 1980 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7426815

RESUMO

One hundred and five microvenous grafts were carried out during three periods of time. Forty-five were performed in 1971, 25 were performed in 1975 and 35 were performed in 1979. The rabbits weighed 2 to 2.5 kg and a standard technique was followed by inserting a 1 cm vein graft after creating a defect of 0.5 cm in the femoral artery, taking the graft from the femoral vein on the same side. Exploration was carried out from 1 to 21 weeks at weekly intervals. The patency rate in Series I (1971) was 71 per cent, whereas the patency rate in Series II (1975) was 96 per cent and in Series III (1979) was 100 per cent. The scanning electron microscope showed that in the short term there was no narrowing of the lumen, nor any microaneurysm formation as reported previously by Buchler and Buncke (1979).


Assuntos
Veia Femoral/transplante , Animais , Artéria Femoral/cirurgia , Artéria Femoral/ultraestrutura , Veia Femoral/ultraestrutura , Microscopia Eletrônica de Varredura , Coelhos , Transplante Autólogo
7.
Ann Plast Surg ; 3(3): 199-210, 1979 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-396851

RESUMO

Lymphaticovenous anastomosis has proved valuable in the treatment of obstructive lymphedema. Histological studies of this anastomosis have shown the lymphatic component to be almost inactive in anastomotic healing. In order to clarify the role of the lymphatics, experimental lymphaticolymphatic anastomoses were performed in canine femoral lymphatics. The technique developed calls for eight to ten 19 mu sutures to prevent vessel wall collapse, and preservation of the vasa vasorum. Vessels were harvested from one hour to six weeks after anastomosis. Scanning electron microscopy and conventional light histology revealed the lymphatics to have active healing of the intima with complete reendothelialization by two weeks. The techniques developed in this study are directly applicable to human lymphaticovenous anastomosis.


Assuntos
Sistema Linfático/cirurgia , Microcirurgia/métodos , Animais , Modelos Animais de Doenças , Cães , Fêmur , Sistema Linfático/ultraestrutura , Microscopia Eletrônica de Varredura , Coelhos , Técnicas de Sutura , Vasa Vasorum/cirurgia , Cicatrização
9.
Pathology ; 10(1): 27-44, 1978 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-580448

RESUMO

Small blood vessels within areas of chronic inflammation which contain large numbers of lymphocytes develop unusually thick walls. Combined histological and electron microscope study shows that the thickening is due to hypertrophy of endothelial cells which come to resemble the endothelium of post-capillary venules in lymphoid tissue. Vessels of this type have been found in experimental granulomas induced by injection of Freund's adjuvant or killed tubercle bacilli and in human biopsy material from cases of rheumatoid arthritis and Hashimoto's disease of the thyroid. Comparison with the developing Peyer's patch in young rats shows that the unusual vessels in granulomas are very similar in endothelial cell size, pattern of distribution, extent of lymphocyte migration and degree of carbon leakage to post-capillary venules of the immature Peyer's patch. Study of the time at which lymphocytes appear in large numbers within the granuloma or developing Peyer's patch and the time at which thickened vessels are first seen suggest tha the endothelial changes are a consequence and not a cause of lymphocyte emigration. The stimulus to endothelial hyperthrophy appears to be massive sustained migration of lymphocytes, but the functional significance of this change in vascular structure is not clear.


Assuntos
Inflamação/patologia , Linfócitos/fisiologia , Veias/patologia , Vênulas/patologia , Animais , Doença Crônica , Endotélio/patologia , Granuloma/patologia , Inflamação/fisiopatologia , Masculino , Microscopia Eletrônica , Neoplasias Experimentais/patologia , Nódulos Linfáticos Agregados/patologia , Ratos , Tireoidite Autoimune/patologia
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