6,329 research outputs found
Ortodeoxia recorrente e foramen ovale patente.
Introdução: Foramen ovale patente (FOP)
ocorre em até 25% dos adultos saudáveis.
Pode favorecer embolização paradoxal,
enxaqueca e insuficiência respiratória (IR).
Apresenta-se caso de IR e ortodeoxia por
shunt direito-esquerdo via FOP sem
evidência prévia de aumento da pressão
intra-auricular direita. Encerramento do
FOP resolveu eficazmente IR.
Caso clínico: Homem, 52 anos. Mieloma
múltiplo IgA/k diagnosticado um ano antes.
Internado por IR hipoxémica grave com
ortodeoxia e má resposta à oxigenoterapia,
após colocação de cateter venoso central
(CVC) na subclávia direita. Referia
parestesias e alterações visuais
inespecíficas, após manipulações do CVC.
Características da IR sugeriam shunt entre
circulação pulmonar e sistémica. Sem
evidência clínica ou imagiológica de shunt
intra-pulmonar. Ecocardiograma
transtorácico com contraste: shunt direito-
-esquerdo. Ecocardiograma transesofágico:
FOP. Cateterismo cardíaco (após resolução
espontânea da IR): sem shunt. Uma semana
depois recorreu IR grave, que resolveu (bem
como queixas neurológicas) com
encerramento do FOP.
Discussão: IR por shunt intra-cardíaco sem
aumento da pressão nas cavidades direitas é
de difícil interpretação hemodinâmica.
Raros relatos (em adultos) associam esta
entidade a anomalias anatómicas, que favorecerão shunt por orientação
preferencial do fluxo sanguíneo para o FOP.
São exemplos parésia diafragmática direita
e ectasia da aorta ascendente, identificadas
no doente apresentado. O papel do CVC,
colocado imediatamente antes da IR, é
especulativo. O completo sucesso
terapêutico após encerramento do FOP
apoia o diagnóstico.
Conclusão: Avaliar correctamente IR
(pesquisar ortodeoxia e resposta à
oxigenoterapia) permite suspeitar de shunt,
que se diagnostica utilizando meios
acessíveis, seguros e rentáveis. Shunt
intra-cardíaco sem aumento da pressão à
direita deve ser considerado porque tem
tratamento eficaz. Background: Patent foramen ovale (PFO)
occurs in 25% of healthy adults. It can lead
to paradoxical embolization, migraine and
respiratory failure (RF). The authors present
a case of RF and orthodeoxia due to a rightto-
left shunt via a PFO without previous elevation
of right atrial pressure. Closure of the
PFO effectively resolved the RF.
Case report: A 52-year-old man, with IgA-k
multiple myeloma diagnosed one year
before, was admitted for severe hypoxemic
RF, with orthodeoxia and poor response to
oxygen supplementation, after placement of
a central venous catheter (CVC) in the right
subclavian vein. The patient reported paresthesia
and nonspecific visual changes after
manipulation of the CVC. The RF suggested
a shunt between the pulmonary and systemic
circulations. There was no clinical or
radiological evidence of an intrapulmonary
shunt. Contrast echocardiography showed a
right-to-left shunt and transesophageal
echocardiography revealed a PFO. Cardiac
catheterization, after spontaneous resolution
of the RF, showed no shunt. A week later,
severe RF recurred. Complete resolution of
respiratory dysfunction and neurological
symptoms was seen after PFO closure.
Discussion: RF due to an intracardiac shunt
without increased right-sided pressure is hemodynamically difficult to interpret. A
few reports (in adults) relate this entity to
anatomical anomalies, which can lead to a
shunt by directing blood flow preferentially
to the PFO. Examples include right
diaphragmatic paresis and ectasia of the
ascending aorta, which were observed in
this patient. The role of the CVC, which was
placed immediately before the RF, is uncertain.
Complete therapeutic success after closure
of the PFO supports the diagnosis.
Conclusion: Correct evaluation of RF (by
investigating orthodeoxia and response to
oxygen therapy) enables the suspicion of a
shunt, which can be confirmed through simple,
safe and cost-effective exams.
Intracardiac shunt without increased rightsided
pressure should be considered
because it can be successfully treatment
Water activity in lamellar stacks of lipid bilayers: "Hydration forces" revisited
Water activity and its relationship with interactions stabilising lamellar
stacks of mixed lipid bilayers in their fluid state are investigated by means
of osmotic pressure measurements coupled with small-angle x-ray scattering. The
(electrically-neutral) bilayers are composed of a mixture in various
proportions of lecithin, a zwitterionic phospholipid, and Simulsol, a non-ionic
cosurfactant with an ethoxylated polar head. For highly dehydrated samples the
osmotic pressure profile always exhibits the "classical" exponential decay as
hydration increases but, depending on Simulsol to lecithin ratio, it becomes
either of the "bound" or "unbound" types for more water-swollen systems. A
simple thermodynamic model is used for interpreting the results without
resorting to the celebrated but elusive "hydration forces"Comment: 24 pages, 12 figures. Accepted for publication in The European
Physical Journal
Developing a site-conditions map for seismic hazard Assessment in Portugal
The evaluation of site effects on a broad scale is a critical issue for seismic hazard and risk assessment, land use planning and emergency planning. As characterization of site conditions based on the shear-wave velocity has become increasingly important, several methods have been proposed in the literature to estimate its average over the first thirty meters (Vs30) from more extensively available data. These methods include correlations with geologic-geographic defined units and topographic slope. In this paper we present the first steps towards the development of a site–conditions map for Portugal, based on a regional database of shear-wave velocity data, together with geological, geographic, and lithological information. We computed Vs30 for each database site and classified it according to the corresponding geological-lithological information using maps at the smallest scale available (usually 1:50000). We evaluated the consistency of Vs30 values within generalized-geological classes, and assessed the performance of expedient methodologies proposed in the literature
Experimental realization of the Yang-Baxter Equation via NMR interferometry
The Yang-Baxter equation is an important tool in theoretical physics, with
many applications in different domains that span from condensed matter to
string theory. Recently, the interest on the equation has increased due to its
connection to quantum information processing. It has been shown that the
Yang-Baxter equation is closely related to quantum entanglement and quantum
computation. Therefore, owing to the broad relevance of this equation, besides
theoretical studies, it also became significant to pursue its experimental
implementation. Here, we show an experimental realization of the Yang-Baxter
equation and verify its validity through a Nuclear Magnetic Resonance (NMR)
interferometric setup. Our experiment was performed on a liquid state
Iodotrifluoroethylene sample which contains molecules with three qubits. We use
Controlled-transfer gates that allow us to build a pseudo-pure state from which
we are able to apply a quantum information protocol that implements the
Yang-Baxter equation.Comment: 10 pages and 6 figure
Application of a 235 rRNA Fluorescent In Situ Hybridization method for rapid detection of Salmonella sp. in slaughtered pigs
Pork products contamination during the slaughter process represents an important vehicle of Salmonella sp. dissemination to humans. It\u27s urgent to develop rapid, sensitive and accurate methods that allow the detection of a large number of Sa/monel/a-positive samples, in order to control these risks efficiently and in a practical time. This study evaluates the suitability of Fluorescent In Situ Hybridization (FISH) method as a rapid screening tool for Salmonella sp. deteclton in pork carcasses, as well in some risk tissues (ileum, ileocolic and mandibular lymph nodes and tonsils), which could be involved in Salmonella contamination during slaughter process. For that, FISH was comparatively analysed with the labour intenstve reference microbiological culture method (ISO 6579:2002) whose results were previously published by the same authors
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