Singular riemannian foliations with sections, transnormal maps and basic forms

A singular riemannian foliation F on a complete riemannian manifold M is said to admit sections if each regular point of M is contained in a complete totally geodesic immersed submanifold (a section) that meets every leaf of F orthogonally and whose dimension is the codimension of the regular leaves of F. We prove that the algebra of basic forms of M relative to F is isomorphic to the algebra of those differential forms on a section that are invariant under the generalized Weyl pseudogroup of this section. This extends a result of Michor for polar actions. It follows from this result that the algebra of basic function is finitely generated if the sections are compact. We also prove that the leaves of F coincide with the level sets of a transnormal map (generalization of isoparametric map) if M is simply connected, the sections are flat and the leaves of F are compact. This result extends previous results due to Carter and West, Terng, and Heintze, Liu and Olmos.Comment: Preprint IME-USP; The final publication is available at springerlink.com http://www.springerlink.com/content/q48682633730t831

Polar foliations and isoparametric maps

A singular Riemannian foliation $F$ on a complete Riemannian manifold $M$ is called a polar foliation if, for each regular point $p$, there is an immersed submanifold $\Sigma$, called section, that passes through $p$ and that meets all the leaves and always perpendicularly. A typical example of a polar foliation is the partition of $M$ into the orbits of a polar action, i.e., an isometric action with sections. In this work we prove that the leaves of $F$ coincide with the level sets of a smooth map $H: M\to \Sigma$ if $M$ is simply connected. In particular, we have that the orbits of a polar action on a simply connected space are level sets of an isoparametric map. This result extends previous results due to the author and Gorodski, Heintze, Liu and Olmos, Carter and West, and Terng.Comment: 9 pages; The final publication is available at springerlink.com http://www.springerlink.com/content/c72g4q5350g513n1

Endometriosis: A Rare Cause of Large Bowel Obstruction.

Large bowel obstruction can result in significant morbidity and mortality, especially in cases of acute complete obstruction. There are many possible causes, the most common in adults being colorectal cancer. Endometriosis is a benign disease, and the most affected extragenital location is the bowel, especially the rectosigmoid junction. However, transmural involvement and acute occlusion are very rare events. We report an exceptional case of acute large bowel obstruction as the initial presentation of endometriosis. The differential diagnosis of colorectal carcinoma may be challenging, and this case emphasizes the need to consider intestinal endometriosis in females at a fertile age presenting with gastrointestinal symptoms and an intestinal mass causing complete large bowel obstruction.info:eu-repo/semantics/publishedVersio

Pancreatoscopy-guided laser lithotripsy in a patient with difficult ductal stone

info:eu-repo/semantics/publishedVersio

Endoscopy Timing in Patients with Acute Upper Gastrointestinal Bleeding.

BACKGROUND/AIMS: The role of very early (≤12 hours) endoscopy in nonvariceal upper gastrointestinal bleeding is controversial. We aimed to compare results of very early and early (12-24 hours) endoscopy in patients with upper gastrointestinal bleeding demonstrating low-risk versus high-risk features and nonvariceal versus variceal bleeding. METHODS: : This retrospective study included patients with nonvariceal and variceal upper gastrointestinal bleeding. The primary outcome was a composite of inpatient death, rebleeding, or need for surgery or intensive care unit admission. Endoscopy timing was defined as very early and early. We performed the analysis in two subgroups: (1) high-risk vs. low-risk patients and (2) variceal vs. nonvariceal bleeding. RESULTS: : A total of 102 patients were included, of whom 59.8% underwent urgent endoscopy. Patients who underwent very early endoscopy received endoscopic therapy more frequently (p=0.001), but there was no improvement in other clinical outcomes. Furthermore, patients at low risk and with nonvariceal bleeding who underwent very early endoscopy had a higher risk of the composite outcome. CONCLUSION: s: Very early endoscopy does not seem to be associated with improved clinical outcomes and may lead to poorer outcomes in specific populations with upper gastrointestinal bleeding. The actual benefit of very early endoscopy remains controversial and should be further clarified.info:eu-repo/semantics/publishedVersio

Oclusão intestinal: uma causa rara na mulher jovem: caso clínico

Sexo feminino, 30 anos, sem antecedentes. Recorre à urgência por vómitos, paragem de emissão de gases e fezes, distensão abdominal e dor abdominal difusa tipo cólica. Observação: abdómen distendido, timpanizado, ligeiramente doloroso, sem defesa. PCR 0.51 mg/dL. Radiografia simples abdómen: distensão cólica e stop na transição reto-sigmoideia. TC abdominal: “espessamento parietal concêntrico na transição reto-sigmoideia com dilatação das ansas a montante. Ascite ligeira”. Submetida a laparotomia exploradora constatando-se processo inflamatório peri-uterino com envolvimento da parede anterior do reto. Fez-se resseção anterior do reto com anastomose primária e ileostomia de proteção. Anátomo-patologia: endometriose rectal e nodal, margens cirúrgicas livres. Três meses depois fez retossigmoidoscopia até anastomose, com mucosa intensamente edemaciada e hiperemiada, com estenose inultrapassável. RMN pélvica: “útero bicórneo, múltiplas áreas de endometriose superficial e profunda, uma delas em contacto com a vertente anterior do reto alto, sem nódulos volumosos na zona da anastomose”. Inicia tratamento com agonista LHRH durante 3 meses. RMN de reavaliação: “evolução favorável, redução dimensões dos focos de endometriose e franca redução do sinal, traduzindo evolução para fibrose”. Repete retossigmoidoscopia: melhoria da estenose, mas ainda infranqueável; dilatação endoscópica com balão TTS até 15 mm, seguida de cirurgia de reconstrução do trânsito. Após 3 meses doente assintomática. A endometriose intestinal é uma causa rara de oclusão intestinal. O envolvimento intestinal é a localização extra-pélvica mais comum da doença, com prevalência 5.3%-12%. O reto-sigmóide são as porções mais envolvidas (90%), mas o envolvimento transmural é raro. O diagnóstico pré-operatório é desafiante, com múltiplos diagnósticos diferenciais, nomeadamente neoplasia.N/

Clostridia Initiate Heavy Metal Bioremoval in Mixed Sulfidogenic Cultures

Sulfate reducing bacteria (SRB) are widely used for attenuating heavy metal pollution by means of sulfide generation. Due to their low metal tolerance, several SRB species depend on associated bacteria in mixed cultures to cope with metal-induced stress. Yet the identity of the SRB protecting bacteria is largely unknown. We aimed to identify these associated bacteria and their potential role in two highly metal-resistant mixed SRB cultures by comparing bacterial community composition and SRB activity between these cultures and two sensitive ones. The SRB composition in the resistant and sensitive consortia was similar. However, whereas the SRB in the sensitive cultures were strongly inhibited by a mixture of copper, zinc, and iron, no influence of these metals was detected on SRB growth and activity in the resistant cultures. In the latter, a Gram-positive population mostly assigned to Clostridium spp.initiated heavy metal bioremoval based on sulfide generation from components of the medium (mainly sulfite) but not from sulfate. After metal levels were lowered by the Clostridium spp. populations, SRB started sulfate reduction and raised the pH of the medium. The combination of sulfite reducing Clostridium spp. with SRB may improve green technologies for removal of heavy metals

Abordagem clínica da cirrose hepática: protocolos de atuação

Coordenação de: Alexandra Martins, Joana Carvalho e Branco, Jorge ReisN/