Necrotizing enterocolitis (NEC), a severe inflammatory disorder of the gastrointestinal tract with high morbidity and mortality, affects primarily preterm infants. The diagnosis represents a challenging task, and no biomarker has been found to aid early diagnosis with high accuracy. Microdialysis has been widely used to detect metabolites of anaerobic metabolism, enabling a local and early detection of ischemia. This thesis aims to evaluate the possibility of detecting intestinal ischemic stress in experimental and clinical  NEC, by use of rectal intraluminal microdialysis. Intraluminal rectal microdialysis was performed on rats subjected to total intestinal ischemia. Metabolites of ischemia were detectable in both ileum and rectum, with raised glycerol concentrations and lactate/pyruvate ratios. Elevated concentrations of glycerol correlated to increasing intestinal histopathological injury. Experimental early NEC was induced in newborn rat pups, by hypoxia/re-oxygenation treatment. Development of NEC was confirmed by histopathology. Elevated glycerol concentrations were detected by rectal microdialysis. The genetic alterations following experimental NEC in rat pups were studied with microarray. Immunohistochemistry staining was performed for tight junction proteins claudin-1 and claudin-8. Several genes were altered in experimental NEC, mainly genes regulating tight junctions and cell adhesion. Immunohistochemistry revealed reduced expression of claudin-1. A prospective study was conducted on preterm infants with a gestational age of less than 28 weeks. The infants were admitted to a neonatal intensive care unit, and observed during a 4-week period. Rectal microdialysis was performed twice a week, and blood was drawn for analysis of I-FABP. A total of 15 infants were included in the study, whereof four infants developed NEC, and 11 served as controls. Rectal glycerol and I-FABP displayed high concentrations, which varied considerably during the observation periods, both in NEC and controls. No differences in either glycerol or I-FABP concentrations were seen in the NEC-group vs. the controls. In conclusion, rectal microdialysis can detect metabolites of intestinal ischemia, both in experimental and clinical NEC. Rectal microdialysis is safe and could provide a valuable non-invasive aid to detect hypoxia-induced intestinal damage or ischemic stress in extremely preterm infants. In this study however, it was not possible to predict the development of clinical NEC using microdialysis or I-FABP.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 5 uppsatser.

Thesis (Ph.D.)--University of Wollongong, 2005. / Typescript. Includes bibliographical references: leaf 140-179.

The purpose of this review of literature is to understand the current state of the science and to make recommendations for practice and research in regards to the gastrointestinal condition affecting premature infants, necrotizing enterocolitis (NEC). Emphasis is placed on reviewing the literature to identify prevention strategies nurses can use to reduce the incidence, morbidity and mortality of NEC. The introduction will focus on discussing the problem of NEC including its risk factors, pathophysiology, and disease presentation. The findings sections will focus on the most promising and researched areas of intervention. The discussion section will focus on how this knowledge can be translated into practice and what nurses can do about it. The research will be conducted through nursing databases with conceptual primary sources that will further expand upon the selected studies on this topic.

No description available.

published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

No description available.

A sialometaplasia necrosante é uma lesão inflamatória das glândulas salivares, autolimitante, com reparação entre uma e dez semanas, cuja etiopatogenia está associada ao infarto por obstrução dos vasos sangüíneos. O seu conhecimento tem grande importância na prática diária pela semelhança com lesões malignas. As lesões necróticas no palato duro induzidas por aparelhos dentomucossuportados são provavelmente sialometaplasias necrosantes de natureza iatrogênica com relação causa-efeito estabelecida. Analisaram-se todos os espécimes de sialometaplasia necrosante dos registros do Serviço de Anatomia Patológica da FOB-USP, resgatando todos os casos cadastrados desde 1963 até 2002, a partir de seus respectivos laudos histopatológicos, descrevendo as características registradas na clínica e na análise microscópica óptica. Um caso clínico de lesão necrótica no palato duro induzida por aparelho disjuntor palatino foi explorado quanto à sua evolução, relações etiopatogênicas e conduta adotada. A partir dos resultados obtidos pelo nosso trabalho, concluímos que: 1) a sialometaplasia necrosante pode ser distinguida microscopicamente das lesões malignas. Em alguns casos torna-se fundamental a história clínica para diagnosticar de forma mais precisa e segura. Quando não existe uma relação causa-efeito, a biópsia é indispensável; 2) o soalho bucal e o palato duro são os locais mais afetados e o trauma é o agente etiológico mais comum para a sua ocorrência e 3) as lesões na mucosa palatina provocadas por aparelhos dentomucossuportados podem ser sialometaplasias necrosantes. Por apresentar uma relação causa-efeito muito bem estabelecida, em geral não são biopsiadas e diagnosticadas microscopicamente. Alívios nas trajetórias das artérias palatinas maiores devem ser confeccionados para prevenir a sua ocorrência. / Necrotizing sialometaplasia is an inflammatory lesion of salivary glands, which has shown self- limitation and self-repairing within one and ten weeks. Its aetiopathogenesis is associated to infarction and necrosis caused by obstruction of the blood supply. The resemblance of such lesion with other malignant lesions is very remarkable; therefore the correct diagnosis is of great importance in daily practice. Necrotic lesions on the hard palate induced by RME appliances may probably be cause-effect related to necrotizing sialometaplasia of iatrogenic nature. The analyzed specimens of necrotizing sialometaplasia were registered at the Oral Pathology Department, Bauru Dental School, University of São Paulo. The cases were randomed since 1963 according their histopathologic reports, describing clinic and microscopic features. A clinical case of necrotic lesion on the hard palate induced by RME appliance was explored concerning evolution, procedure adopted and aetiopathogenic relations. The results of our study allowed us to conclude that: 1) necrotizing sialometaplasia may be microscopically distinguished from other malignant lesions. In some cases, clinical history is indispensable for accurate diagnosis. Biopsy is vital when the cause-effect relation is not evident; 2) the hard palate and mouth floor are the most affected sites and trauma is the main aetiological factor; 3) lesions in the oral mucosa caused by dentoskeletal anchorage appliances may be iatrogenic necrotizing sialometaplasia and should not be biopsied or diagnosed microscopically due to the well established cause-effect relation. To avoid any pathological outcome, the expansion appliance acrylic, should be designed with close attention to the location of the greater palatine artery and other palatal vascular features.

A sialometaplasia necrosante é uma lesão inflamatória das glândulas salivares, autolimitante, com reparação entre uma e dez semanas, cuja etiopatogenia está associada ao infarto por obstrução dos vasos sangüíneos. O seu conhecimento tem grande importância na prática diária pela semelhança com lesões malignas. As lesões necróticas no palato duro induzidas por aparelhos dentomucossuportados são provavelmente sialometaplasias necrosantes de natureza iatrogênica com relação causa-efeito estabelecida. Analisaram-se todos os espécimes de sialometaplasia necrosante dos registros do Serviço de Anatomia Patológica da FOB-USP, resgatando todos os casos cadastrados desde 1963 até 2002, a partir de seus respectivos laudos histopatológicos, descrevendo as características registradas na clínica e na análise microscópica óptica. Um caso clínico de lesão necrótica no palato duro induzida por aparelho disjuntor palatino foi explorado quanto à sua evolução, relações etiopatogênicas e conduta adotada. A partir dos resultados obtidos pelo nosso trabalho, concluímos que: 1) a sialometaplasia necrosante pode ser distinguida microscopicamente das lesões malignas. Em alguns casos torna-se fundamental a história clínica para diagnosticar de forma mais precisa e segura. Quando não existe uma relação causa-efeito, a biópsia é indispensável; 2) o soalho bucal e o palato duro são os locais mais afetados e o trauma é o agente etiológico mais comum para a sua ocorrência e 3) as lesões na mucosa palatina provocadas por aparelhos dentomucossuportados podem ser sialometaplasias necrosantes. Por apresentar uma relação causa-efeito muito bem estabelecida, em geral não são biopsiadas e diagnosticadas microscopicamente. Alívios nas trajetórias das artérias palatinas maiores devem ser confeccionados para prevenir a sua ocorrência. / Necrotizing sialometaplasia is an inflammatory lesion of salivary glands, which has shown self- limitation and self-repairing within one and ten weeks. Its aetiopathogenesis is associated to infarction and necrosis caused by obstruction of the blood supply. The resemblance of such lesion with other malignant lesions is very remarkable; therefore the correct diagnosis is of great importance in daily practice. Necrotic lesions on the hard palate induced by RME appliances may probably be cause-effect related to necrotizing sialometaplasia of iatrogenic nature. The analyzed specimens of necrotizing sialometaplasia were registered at the Oral Pathology Department, Bauru Dental School, University of São Paulo. The cases were randomed since 1963 according their histopathologic reports, describing clinic and microscopic features. A clinical case of necrotic lesion on the hard palate induced by RME appliance was explored concerning evolution, procedure adopted and aetiopathogenic relations. The results of our study allowed us to conclude that: 1) necrotizing sialometaplasia may be microscopically distinguished from other malignant lesions. In some cases, clinical history is indispensable for accurate diagnosis. Biopsy is vital when the cause-effect relation is not evident; 2) the hard palate and mouth floor are the most affected sites and trauma is the main aetiological factor; 3) lesions in the oral mucosa caused by dentoskeletal anchorage appliances may be iatrogenic necrotizing sialometaplasia and should not be biopsied or diagnosed microscopically due to the well established cause-effect relation. To avoid any pathological outcome, the expansion appliance acrylic, should be designed with close attention to the location of the greater palatine artery and other palatal vascular features.

Thesis (Ph.D.)--University of Wollongong, 2006. / Typescript. Includes bibliographical references: leaf 148-160.