979 resultados para VARICOSE-VEINS
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Offprint: American journal of anatomy. Vol. 1, no. 3 (May 26, 1902).
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Dissertation I. On the question, Is there any communication from the stomach to the bladder, more direct than that through the circulating system and the kidneys? Which obtained the Boylston premium in 1819.--Dissertation II. On the question, Can medicinal substances be safely and advantageously introduced into animal bodies through the medium of the veins? Which obtained the Boylston premium in 1821.
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Mode of access: Internet.
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This study investigated the nature of vasodilator mechanisms in the dorsal aorta of the giant shovelnose ray, Rhinobatus typus. Anatomical techniques found no evidence for an endothelial nitric oxide synthase, but neural nitric oxide synthase was found to be present in the perivascular nerve fibres of the dorsal aorta and other arteries and veins using both NADPH-diaphorase staining and immunohistochemistry with a specific neural NOS antibody. Arteries and veins both contained large nNOS-positive nerve trunks from which smaller nNOS-positive bundles branched and formed a plexus in the vessel wall. Single, varicose nNOS-positive nerve fibres were present in both arteries and veins. Within the large bundles of both arteries and veins, groups of nNOS-positive cell bodies forming microganglia were observed. Double-labelling immunohistochemistry using an antibody to tyrosine hydroxylase showed that nearly all the NOS nerves were not sympathetic. Acetylcholine always caused constriction of isolated rings of the dorsal aorta and the nitric oxide donor, sodium nitroprusside, did not mediate any dilation. Addition of nicotine (3 x 10(-4) M) to preconstricted rings caused a vasodilation that was not affected by the nitric oxide synthase inhibitor, L-NNA (10(-4) M), nor the soluble guanylyl cyclase inhibitor, ODQ (10(-5) M). This nicotine-mediated vasodilation was, therefore, not due to the synthesis and release of NO. Disruption of the endothelium significantly reduced or eliminated the nicotine-mediated vasodilation. In addition. indomethacin (10(-5) M), an inhibitor of cyclooxygenases, significantly increased the time period to maximal dilation and reduced, but did not completely inhibit the nicotine-mediated vasodilation. These data support the hypothesis that a prostaglandin is released from the vascular endothelium of a batoid ray, as has been described previously in other groups of fishes. The function of the nitrergic innervation of the blood vessels is not known because nitric oxide does not appear to regulate vascular tone. (C) 2003 Elsevier Inc. All rights reserved.
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A granodiorite from Akilia, southwest Greenland, previously suggested to date putative life-bearing rocks to greater than or equal to3.84 Ga, is re-investigated using whole-rock major and trace-element geochemistry, and detailed cathodoluminescence image-guided secondary ion mass spectrometer analyses of zircon U-Th-Pb and rare earth elements. Complex zircon internal structure reveals three episodes of zircon growth and/or recrystallization dated to c. 3.84 Ga, 3.62 Ga and 2.71 Ga. Rare earth element abundances imply a significant role for garnet in zircon generation at 3.62 Ga and 2.71 Ga. The 3.62 Ga event is interpreted as partial melting of a c. 3.84 Ga grey gneiss precursor at granulite facies with residual garnet. Migration of this 3.62 Ga magma (or melt-crystal mush) away from the melt source places a maximum age limit on any intrusive relationship. These early Archaean relationships have been complicated further by isotopic reworking in the 2.71 Ga event, which could have included a further episode of partial melting. This study highlights a general problem associated with dating thin gneissic veins in polyphase metamorphic terranes, where field relationships may be ambiguous and zircon inheritance can be expected.
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Drilling a complete deep crustal section has been a primary yet elusive goal since the inception of scientific ocean drilling. In situ ocean crustal sections would contribute enormously to our understanding of the formation and subsequent evolution of the ocean crust, in particular the interplay between magmatic, hydrothermal, and tectonic processes. Ocean Drilling Program (ODP) Leg 206 was the first of a multileg project to drill an in situ crustal section that penetrated the gabbroic rocks of the Cocos plate (6°44.2'N, 91°56.1'W), which formed ~15 m.y. ago on the East Pacific Rise during a period of superfast spreading (>200 mm/yr) (Wilson, Teagle, Acton, et al., 2003, doi:10.2973/odp.proc.ir.206.2003). During Leg 206, the upper 500 m of basement was cored in Holes 1256C and 1256D with moderate to high recovery rates. The igneous rocks recovered are predominantly thin (10 cm to 3 m) basalt flows separated by chilled margins. There are also several massive flows (>3 m thick), although their abundance decreases with depth in Hole 1256D, as well as minor pillow basalts, hyaloclastites, and rare dikes. The lavas have been slightly (<10%) altered by low-temperature hydrothermal fluids, which resulted in pervasive dark gray background alteration and precipitation of saponite, pyrite, silica, celadonite, and calcium carbonate veins. Here we present a geochemical analysis of the CaCO3 recovered from cores. The compositions of ridge flank fluids within superfast spreading crust will be determined from these data, following the approach of Hart et al. (1994, doi:10.1029/93JB02035), Yatabe et al. (2000, doi:10.2973/odp.proc.sr.168.003.2000), and Coggon et al. (2004, doi:10.1016/S0012-821X(03)00697-6).
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During Legs 118 and 176, Ocean Drilling Program Hole 735B, located on Atlantis Bank on the Southwest Indian Ridge, was drilled to a total depth of 1508 meters below seafloor (mbsf) with nearly 87% recovery. The recovered core provides a unique section of oceanic Layer 3 produced at an ultraslow spreading ridge. Metamorphism and alteration are extensive in the section but decrease markedly downward. Both magmatic and hydrothermal veins are present in the core, and these were active conduits for melt and fluid in the crust. We have identified seven major types of veins in the core: felsic and plagioclase rich, plagioclase + amphibole, amphibole, diopside and diopside + plagioclase, smectite ± prehnite ± carbonate, zeolite ± prehnite ± carbonate, and carbonate. A few epidote and chlorite veins are also present but are volumetrically insignificant. Amphibole veins are most abundant in the upper 50 m of the core and disappear entirely below 520 mbsf. Felsic and plagioclase ± amphibole ± diopside veins dominate between ~50 and 800 mbsf, and low-temperature smectite, zeolite, and prehnite veins are present in the lower 500 m of the core. Carbonate veinlets are randomly present throughout the core but are most abundant in the lower portions. The amphibole veins are closely associated with zones of intense crystal plastic deformation formed at the brittle/ductile boundary at temperatures above 700°C. The felsic and plagioclase-rich veins were formed originally by late magmatic fluids at temperatures above 800°C, but nearly all of these have been overprinted by intense hydrothermal alteration at temperatures between 300° and 600°C. The zeolite, prehnite, and smectite veins formed at temperatures <100°C. The chemistry of the felsic veins closely reflects their dominant minerals, chiefly plagioclase and amphibole. The plagioclase is highly zoned with cores of calcic andesine and rims of sodic oligoclase or albite. In the felsic veins the amphibole ranges from magnesio-hornblende to actinolite or ferro-actinolite, whereas in the monomineralic amphibole veins it is largely edenite and magnesio-hornblende. Diopside has a very narrow range of composition but does exhibit some zoning in Fe and Mg. The felsic and plagioclase-rich veins were originally intruded during brittle fracture at the ridge crest. The monomineralic amphibole veins also formed near the ridge axis during detachment faulting at a time of low magmatic activity. The overprinting of the igneous veins and the formation of the hydrothermal veins occurred as the crustal section migrated across the floor of the rift valley over a period of ~500,000 yr. The late-stage, low-temperature veins were deposited as the section migrated out of the rift valley and into the transverse ridge along the margin of the fracture zone.
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Carbonate veins hosted in ultramafic basement drilled at two sites in the Mid Atlantic Ridge 15°N area record two different stages of fluid-basement interaction. A first generation of carbonate veins consists of calcite and dolomite that formed syn- to postkinematically in tremolite-chlorite schists and serpentine schists that represent gently dipping large-offset faults. These veins formed at temperatures between 90 and 170 °C (oxygen isotope thermometry) and from fluids that show intense exchange of Sr and Li with the basement (87Sr/86Sr = 0.70387 to 0.70641, d7Li L-SVEC = + 3.3 to + 8.6 per mil). Carbon isotopic compositions range to high d13C PDB values (+ 8.7 per mil), indicating that methanogenesis took place at depth. The Sr-Li-C isotopic composition suggests temperatures of fluid-rock interaction that are much higher (T > 350-400 °C) than the temperatures of vein mineral precipitation inferred from oxygen isotopes. A possible explanation for this discrepancy is that fluids cooled conductively during upflow within the presumed detachment fault. Aragonite veins were formed during the last 130 kyrs at low-temperatures within the uplifted serpentinized peridotites. Chemical and isotopic data suggest that the aragonites precipitated from cold seawater, which underwent overall little exchange with the basement. Oxygen isotope compositions indicate an increase in formation temperature of the veins by 8-12 °C within the uppermost ~ 80 m of the subseafloor. This increase corresponds to a high regional geothermal gradient of 100-150 °C/km, characteristic of young lithosphere undergoing rapid uplift.
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This study tested whether myocardial extracellular volume (ECV) is increased in patients with hypertension and atrial fibrillation (AF) undergoing pulmonary vein isolation and whether there is an association between ECV and post-procedural recurrence of AF. Hypertension is associated with myocardial fibrosis, an increase in ECV, and AF. Data linking these findings are limited. T1 measurements pre-contrast and post-contrast in a cardiac magnetic resonance (CMR) study provide a method for quantification of ECV. Consecutive patients with hypertension and recurrent AF referred for pulmonary vein isolation underwent a contrast CMR study with measurement of ECV and were followed up prospectively for a median of 18 months. The endpoint of interest was late recurrence of AF. Patients had elevated left ventricular (LV) volumes, LV mass, left atrial volumes, and increased ECV (patients with AF, 0.34 ± 0.03; healthy control patients, 0.29 ± 0.03; p < 0.001). There were positive associations between ECV and left atrial volume (r = 0.46, p < 0.01) and LV mass and a negative association between ECV and diastolic function (early mitral annular relaxation [E'], r = -0.55, p < 0.001). In the best overall multivariable model, ECV was the strongest predictor of the primary outcome of recurrent AF (hazard ratio: 1.29; 95% confidence interval: 1.15 to 1.44; p < 0.0001) and the secondary composite outcome of recurrent AF, heart failure admission, and death (hazard ratio: 1.35; 95% confidence interval: 1.21 to 1.51; p < 0.0001). Each 10% increase in ECV was associated with a 29% increased risk of recurrent AF. In patients with AF and hypertension, expansion of ECV is associated with diastolic function and left atrial remodeling and is a strong independent predictor of recurrent AF post-pulmonary vein isolation.
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OBJETIVO: avaliar os efeitos da administração da associação zidovudina-lamivudina-ritonavir nos fígados e rins de ratas prenhes e seus conceptos do ponto de vista morfológico e fisiológico. MÉTODOS: 40 ratas albinas prenhes foram aleatoriamente divididas em 4 grupos: 1 controle (Ctrl: controle de veículo) e 3 experimentais (Exp1x, Exp3x e Exp9x). Estes últimos foram tratados por solução oral de zidovudina/lamivudina/ritonavir (Exp1x: 10/5/20 mg/kg; Exp3x: 30/15/60 mg/kg; Exp9x: 90/45/180 mg/kg). As drogas e o veículo foram administrados por gavagem, desde o 1º até o 20º dia de prenhez. No último dia do experimento, todos os animais foram anestesiados e sangue foi retirado da cavidade cardíaca para avaliação sérica das enzimas aspartato aminotransferase (AST) e alanina aminotransferase (ALT), por método calorimétrico, bem como da ureia, determinada por método cinético-enzimático, e creatinina, por método cinético-colorimétrico. Em seguida, fragmentos dos fígados e rins maternos e fetais foram coletados, fixados em formol a 10% e processados segundo os métodos histológicos para inclusão em parafina. Cortes com 5 µm de espessura foram corados pela hematoxilina-eosina (HE) e analisados por microscopia de luz. Na leitura das lâminas, considerou-se o padrão de normalidade para fígado e rins, tais como: hepatócitos, espaço porta íntegros e veias hepáticas bem definidas. Nos rins, a presença de corpúsculos renais, túbulos contorcidos e alças de Henle típicos. Nos fígados fetais considerou-se, ainda, a morfologia das células da linhagem eritrocitária nas diferentes fases do desenvolvimento, bem como os megacariócitos. Quando houve alteração da coloração padrão estabelecida para as estruturas hepáticas e renais, alteração na morfologia de núcleos, rompimento de limites de alguma organela citoplasmática, presença de congestão vascular, tudo isso foi entendido como provavelmente provocado pelas drogas em sua(s) dose(s) de aplicação. A avaliação estatística foi realizada por análise de variância (ANOVA), completada pelo teste de Tukey-Kramer (p<0,05). RESULTADOS: os fígados maternos dos grupos Ctrl, Exp1x e Exp3x mostraram hepatócitos típicos, espaço porta íntegros e veias hepáticas com aspecto normal. No fígado materno do grupo Exp9x, foram encontrados hepatócitos com sinais de atrofia e apoptose (eosinofilia citoplasmática e núcleos picnóticos). Além disso, identificou-se vasodilatação dos capilares sinusoides (congestão). Os rins maternos dos grupos Ctrl e Exp1x apresentaram-se normais, com corpúsculos renais, túbulos contorcidos e alças de Henle típicos. Já nos grupos Exp3x e Exp9x, foram encontrados congestão vascular, glomérulos pequenos ricos em células contendo núcleos hipercromáticos, sendo mais intensos no Exp9x. Com relação aos fígados e rins fetais, não foram observadas alterações morfológicas ou fisiológicas nos grupos estudados. Encontrou-se aumento significante nos níveis da AST (305,70±55,80; p<0,05) e da creatinina (0,50±0,09; p<0,05) no grupo Exp9x. CONCLUSÕES: nossos resultados evidenciam que a administração da associação zidovudina/lamivudina/ritonavir a ratas prenhes em altas doses causa alterações morfológicas e funcionais nos fígados e rins maternos. Não houve alterações nem morfológicas nem fisiológicas nos fígados e rins fetais.
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This work aims at the geochemical study of Pitinga cryolite mineralization through REE and Y analyses in disseminated and massive cryolite ore deposits, as well as in fluorite occurrences. REE signatures in fluorite and cryolite are similar to those in the Madeira albite granite. The highest ΣREE values are found in magmatic cryolite (677 to 1345 ppm); ΣREE is lower in massive cryolite. Average values for the different cryolite types are 10.3 ppm, 6.66 ppm and 8.38 ppm (for nucleated, caramel and white types, respectively). Disseminated fluorite displays higher ΣREE values (1708 and 1526ppm) than fluorite in late veins(34.81ppm). Yttrium concentration is higher in disseminated fluorite and in magmatic cryolite. The evolution of several parameters (REEtotal, LREE/HREE, Y) was followed throughout successive stages of evolution in albite granites and associated mineralization. At the end of the process, late cryolite was formed with low REEtotal content. REE data indicate that the MCD was formed by, and the disseminated ore enriched by (additional formation of hydrothermal disseminated cryolite), hydrothermal fluids, residual from albite granite. The presence of tetrads is poorly defined, although nucleated, caramel and white cryolite types show evidence for tetrad effect.
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Buffalo is an important livestock resource, with a great participation in agricultural systems, providing milk, meat, and work power. Umbilical cord is responsible for maternal-fetal nutrients exchange during pregnancy, and its alterations can compromise the fetal development. We investigated ten pregnant uteruses collected from cross-bread buffaloes in different stages of gestation. Pregnancy and fetal age was determined by measuring the apex sacral length and development period was calculated by previously published formula. Umbilical cords were measured for length determination. Umbilical cord vascular net and anastomosis were observed by injection of Neoprene latex. Histological sections of the umbilical cord were studied after stain with HE, picrossirius, toluidine blue, orceine, and PAS reaction. Buffaloes' umbilical cord was formed by two central arteries, an allantois duct and two peripheral veins. The artery wall was composed by large quantity of collagen, elastic fibers, fibroblasts and large number of vasa vasorum. The allantois duct was located between the arteries and presented a great number of small nourishing vessels. Small nourishing vessels should be carefully considered to avoid to be mistaken to the arterials and veins vasa vasorum. Medium length of umbilical cord from buffalos was 11.8cm (minimum of 6.8cm and maximum of 17.4cm).
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A distribuição intraparenquimal das veias porta-hepáticas foi estudada em 30 gansos domésticos. Latex Neoprene corado foi injetado pela veia isquiática e os animais forma fixados por imersão e injeção intramuscular com formol a 10% e dissecados. O fígado esteve composto por um grande lobo hepático direito e por um lobo hepático esquerdo menor, os quais estiveram conectados por uma ponte de parênquima. O lobo direito do fígado teve exclusivamente vasos do sistema porta-hepático formados pela distribuição intraparenquimal da veia porta-hepática direita, enquanto que no lobo esquerdo estes originaram-se da veia porta-hepática direita e de pequenas veias porta-hepáticas esquerdas. A veia porta-hepática direita emitiu o ramo caudal direito, que emitiu um pequeno ramo caudolateral direito e um grande ramo caudomedial direito. Cranialmente esta veia emitiu os ramos craniais direito e ramos lateral direito. A porção transversa da veia porta-hepática direita cruzou para o lobo hepático esquerdo, emitindo de 1 a 6 pequenos ramos craniais e caudais para a região média do fígado. No lobo esquerdo, o ramo esquerdo da veia porta-hepática direita emitiu o ramo cranial esquerdo, o ramo lateral esquerdo e o ramo medial. De 1 a 6 veias porta-hepáticas esquerdas foram identificadas desembocando ou no ramo esquerdo da veia porta-hepática direita ou em sua porção transversa, oriundos do ventrículo gástrico e do pró-ventrículo. Em 40% dos gansos uma veia porta-hepática própria oriunda da confluência de vasos venosos da face esquerda do ventrículo distribuiu-se na extremidade caudal do lobo esquerdo isoladamente.