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1.
J Perinatol ; 36(10): 862-9, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27388941

RESUMO

OBJECTIVE: Neonates with necrotizing enterocolitis (NEC) have higher calprotectin levels in stool than do healthy neonates. However, it is not known whether high stool calprotectin at the onset of bowel symptoms identifies neonates who truly have NEC vs other bowel disorders. STUDY DESIGN: Neonates were eligible for this study when an x-ray was ordered to 'rule-out NEC'. Stool calprotectin was quantified at that time and in a follow-up stool. Each episode was later categorized as NEC or not NEC. The location of calprotectin in the bowel was determined by immunohistochemistry. RESULTS: Neonates with NEC had higher initial and follow-up stool calprotectin levels than did neonates without NEC. Calprotectin in bowel from neonates with NEC was within neutrophil extracellular traps (NETs). CONCLUSION: At the onset of signs concerning for NEC, fecal calprotectin is likely to be higher in neonates with NEC. Calprotectin in their stools is exported from neutrophils via NETs.


Assuntos
Enterocolite Necrosante/diagnóstico , Fezes/química , Complexo Antígeno L1 Leucocitário/análise , Neutrófilos/metabolismo , Biomarcadores/análise , Estudos de Casos e Controles , Enterocolite Necrosante/metabolismo , Enterocolite Necrosante/patologia , Armadilhas Extracelulares/metabolismo , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Doenças do Prematuro/diagnóstico , Doenças do Prematuro/metabolismo , Recém-Nascido de muito Baixo Peso , Complexo Antígeno L1 Leucocitário/metabolismo , Projetos Piloto , Estudos Prospectivos , Radiografia , Índice de Gravidade de Doença
2.
J Perinatol ; 34(1): 16-21, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24030677

RESUMO

OBJECTIVE: The American College of Obstetrics and Gynecology Committee on Obstetric Practice recently endorsed delayed cord clamping at preterm delivery. However, the committee report expressed the concern by some practitioners that delayed clamping or cord milking might induce hyperviscosity in preterm neonates. To address this issue we: (1) established reference ranges for whole-blood viscosity among preterm neonates (viscosity reference ranges had previously been reported only in term neonates) and (2) determined the effect of umbilical cord milking at deliveries <32 weeks gestation on subsequent blood viscosity measurements. STUDY DESIGN: This was a prospective study in two Neonatal Intensive Care Units. Blood viscosity was measured using a cone and plate viscometer. Associations were sought with gestation, hematocrit/hemoglobin and mean corpuscular volume. Reference ranges were determined for preterm infants <32 weeks gestation. Then, after umbilical cord milking at deliveries <32 weeks, viscosity was measured at birth and again during the 12 h after birth. In neonates with viscosities >95th % range, we sought signs of hyperviscosity (plethora, hypotonia, hypoglycemia, hyperbilirubinemia, thrombocytopenia). RESULT: Viscosity at higher and lower sheer rates were linearly related (n=32, r=0.971). Within the range of hematocrits measured (29-63%) viscosity correlated with hematocrit (r=0.877) and hemoglobin (r=0.853) but not with erythrocyte size (r=0.179). Viscosity was related to gestational age (n=58), primarily due to the lower hematocrits at lower gestational ages. In the 12 h after cord milking viscosity ranged from 3.1 to 9.5 centipoise. Three of twenty preterm, neonates had viscosities >95th % reference range. However, all values were well below those where hyperviscosity is defined in term neonates and all lacked features of hyperviscosity. CONCLUSION: Cord blood viscosity is directly proportional to hematocrit/hemoglobin, lower at early gestation and not associated with erythrocyte size. Cord milking at preterm delivery is associated with a low risk of clinical hyperviscosity. Practioners should not refrain from cord milking at preterm delivery because of a concern that it will commonly cause neonatal hyperviscosity.


Assuntos
Viscosidade Sanguínea , Sangue Fetal/fisiologia , Recém-Nascido/sangue , Índices de Eritrócitos , Idade Gestacional , Hematócrito , Humanos , Cuidado do Lactente , Recém-Nascido Prematuro/sangue , Modelos Lineares , Estudos Prospectivos , Cordão Umbilical
3.
Philos Trans A Math Phys Eng Sci ; 370(1974): 4166-75, 2012 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-22869795

RESUMO

The climate change that we are experiencing now is caused by an increase in greenhouse gases due to human activities, including burning fossil fuels, agriculture and deforestation. There is now widespread belief that a global warming of greater than 2(°)C above pre-industrial levels would be dangerous and should therefore be avoided. However, despite growing concerns over climate change and numerous international attempts to agree on reductions of global CO(2) emissions, these have continued to climb. This has led some commentators to suggest more radical 'geoengineering' alternatives to conventional mitigation by reductions in CO(2) emissions. Geoengineering is deliberate intervention in the climate system to counteract man-made global warming. There are two main classes of geoengineering: direct carbon dioxide removal and solar radiation management that aims to cool the planet by reflecting more sunlight back to space. The findings of the review of geoengineering carried out by the UK Royal Society in 2009 are summarized here, including the climate effects, costs, risks and research and governance needs for various approaches. The possible role of geoengineering in a portfolio of responses to climate change is discussed, and various recent initiatives to establish good governance of research activity are reviewed. Key findings include the following.- Geoengineering is not a magic bullet and not an alternative to emissions reductions. - Cutting global greenhouse gas emissions must remain our highest priority. (i) But this is proving to be difficult, and geoengineering may be useful to support it. - Geoengineering is very likely to be technically possible. (i) However, there are major uncertainties and potential risks concerning effectiveness, costs and social and environmental impacts. - Much more research is needed, as well as public engagement and a system of regulation (for both deployment and for possible large-scale field tests). - The acceptability of geoengineering will be determined as much by social, legal and political issues as by scientific and technical factors. Some methods of both types would involve release of materials to the environment, either to the atmosphere or to the oceans, in areas beyond national jurisdiction. The intended impacts on climate would in any case affect many or all countries, possibly to a variable extent. There are therefore inherent international implications for deployment of such geoengineering methods (and possibly also for some forms of research), which need early and collaborative consideration, before any deployment or large-scale experiments could be undertaken responsibly.

4.
Parasitology ; 136(5): 511-21, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19265560

RESUMO

SUMMARY: The spermatozoa of ticks are anomalous in many respects: they are very large, cytoplasm-rich cells which lack a flagellum but move with a peculiar gliding motility. Their metamorphosis after deposition in the female has been well documented, but many of the subsequent events in the career of the spermatozoa are controversial or poorly documented. Our observations of motility imply that the many types of motility that have been reported (up to 5 different types in several reports) can be reduced to 2 apparently independent types of active motility: (1) gliding motility generated along the whole spermatozoon and (2) contortions of the anterior tip of the head. These types of motility appear as a consequence of sperm maturation after transfer to the female, but only become pronounced if the female has taken a recent bloodmeal. A consequence of this enhanced gliding motility after feeding is the movement of the spermatozoa out of the naturally ruptured neck of the spermatophore and up the female genital tract. This occurs without any apparent assistance from the female's musculature and likely is the prime mechanism of movement of the spermatozoa to the site of fertilization.


Assuntos
Ornithodoros/fisiologia , Oviductos/fisiologia , Motilidade dos Espermatozoides , Espermatozoides/fisiologia , Animais , Comportamento Animal , Comportamento Alimentar/fisiologia , Feminino , Masculino , Microscopia Eletrônica de Varredura , Reprodução/fisiologia , Maturação do Esperma , Motilidade dos Espermatozoides/fisiologia
5.
Philos Trans A Math Phys Eng Sci ; 366(1882): 3919-45, 2008 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-18757282

RESUMO

The oceans sequester carbon from the atmosphere partly as a result of biological productivity. Over much of the ocean surface, this productivity is limited by essential nutrients and we discuss whether it is likely that sequestration can be enhanced by supplying limiting nutrients. Various methods of supply have been suggested and we discuss the efficacy of each and the potential side effects that may develop as a result. Our conclusion is that these methods have the potential to enhance sequestration but that the current level of knowledge from the observations and modelling carried out to date does not provide a sound foundation on which to make clear predictions or recommendations. For ocean fertilization to become a viable option to sequester CO2, we need more extensive and targeted fieldwork and better mathematical models of ocean biogeochemical processes. Models are needed both to interpret field observations and to make reliable predictions about the side effects of large-scale fertilization. They would also be an essential tool with which to verify that sequestration has effectively taken place. There is considerable urgency to address climate change mitigation and this demands that new fieldwork plans are developed rapidly. In contrast to previous experiments, these must focus on the specific objective which is to assess the possibilities of CO2 sequestration through fertilization.


Assuntos
Conservação dos Recursos Naturais/métodos , Desastres/prevenção & controle , Ecossistema , Engenharia/tendências , Efeito Estufa , Biologia Marinha/métodos , Oceanos e Mares
6.
J Steroid Biochem Mol Biol ; 103(3-5): 686-8, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17293107

RESUMO

As early as 1930 sunlamps claiming to provide ultraviolet (UV) exposure to make vitamin D were sold to the public in the US and Canada for home use. Today even with dietary supplementation of vitamin D many people do not get enough solar UV exposure to maintain sufficient vitamin D levels. There is growing interest in the availability of sunlamps for this purpose. The original Sperti Sunlamp, with label claiming vitamin D benefit was approved by the American Medical Association in 1940 as a sunlamp. This intermediate pressure mercury lamps ultraviolet B emission lines, at 297, 302, and 313 nm are able to convert 7-dehydrocholesterol in the skin to vitamin pre-D3 initiating the natural process of vitamin D formation. Today's KBD Vitamin D lamp, an updated model of the earlier type source. In order to comply with modern safety guidance, the source is filtered to remove unnecessary UVC radiation and is equipped with a timer to control the dose administered. The 5 min timer provides an exposure, at 20 in. from the user's skin, of one standard erythemal dose (SED). The SED represents a suberythemal dose for even the most sensitive skin type I individual.


Assuntos
Iluminação/instrumentação , Raios Ultravioleta , Vitamina D/biossíntese , Helioterapia/história , Helioterapia/instrumentação , História do Século XX , Humanos , Iluminação/história , Pele/efeitos da radiação
7.
Can Respir J ; 10(7): 391-2, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14571291

RESUMO

Pulmonary sclerosing hemangioma is an unusual benign tumour of uncertain histogenesis. In the past 50 years, hundreds of cases have been described. A case of sclerosing hemangioma with some unusual features, including a false-positive fine needle aspiration biopsy and histological evidence of lymph node metastases, is described.


Assuntos
Hemangioma/diagnóstico , Neoplasias Pulmonares/diagnóstico , Linfonodos/patologia , Adulto , Biópsia por Agulha , Humanos , Neoplasias Pulmonares/patologia , Metástase Linfática , Masculino , Esclerose/diagnóstico , Tomografia Computadorizada por Raios X
8.
Infect Immun ; 68(10): 6056-61, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10992522

RESUMO

Escherichia coli Sonnei has an O antigen identical to that of Plesiomonas shigelloides O17, and its O-antigen gene cluster is located on a plasmid. By sequencing the chromosomal O-antigen gene cluster of P. shigelloides O17 and comparing it with that of Sonnei, we showed that Sonnei gained its O-antigen genes recently.


Assuntos
Genes Bacterianos , Antígenos O/genética , Plasmídeos/genética , Plesiomonas/genética , Shigella sonnei/genética , Sequência de Bases , Cromossomos Bacterianos , Elementos de DNA Transponíveis , Dados de Sequência Molecular , Família Multigênica , Plesiomonas/imunologia , Recombinação Genética , Análise de Sequência de DNA , Shigella sonnei/imunologia
11.
Science ; 262(5135): 828-9, 1993 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-17757341
12.
Carcinogenesis ; 14(5): 1027-33, 1993 May.
Artigo em Inglês | MEDLINE | ID: mdl-8099312

RESUMO

The role of duct cells in the histogenesis of pancreatic carcinoma was studied using a propagable cultured pancreatic duct epithelial cell line derived from a Fischer-344 rat. Tumorigenic transformation was induced by treatment with two experimental pancreatic carcinogens, azaserine and streptozotocin, or spontaneously using a 'selective' culture condition. Tumors arising from spontaneously transformed cells were anaplastic carcinomas, while those from streptozotocin-transformed cells were well or moderately differentiated ductal adenocarcinomas. Azaserine-treated cells produced moderately to poorly differentiated adenocarcinomas. Ultrastructural evidence of acinar or endocrine differentiation was absent. The biochemical phenotypes of representative tumor cell lines established from these tumors were studied. As compared to the parental cell line which expressed high activity of carbonic anhydrase (CA) and negligible activity of gamma-glutamyl transpeptidase (GGT), the tumor cell lines displayed variably increased levels of GGT, and a diminution or loss of CA activity. The tumor cell lines also showed heterogeneity in proto-oncogene and growth factor/receptor expression. The transforming growth factor-alpha mRNA expression was increased in all tumor cell lines, especially in those induced by azaserine. In contrast, mRNA expression of epidermal growth factor receptor was markedly down-regulated in all tumor cell lines. All chemically induced tumor cell lines showed marked overexpression of the c-myc and c-Ki-ras mRNAs, whereas the spontaneously transformed tumor cell line showed only a significant overexpression of the c-Ki-ras. Point mutation of this proto-oncogene at codons 12, 13 or 61 was absent. The results show that azaserine and streptozotocin are potent carcinogens in vitro for cultured rat pancreatic duct epithelial cells, and the phenotype of the tumors is modulated by the method or agent used for their transformation.


Assuntos
Azasserina/toxicidade , Carcinógenos/toxicidade , Transformação Celular Neoplásica , Ductos Pancreáticos/efeitos dos fármacos , Neoplasias Pancreáticas/induzido quimicamente , Estreptozocina/toxicidade , Animais , Northern Blotting , Adesão Celular/efeitos dos fármacos , Ciclo Celular , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Epitélio/efeitos dos fármacos , Epitélio/patologia , Receptores ErbB/genética , Genes myc , Genes ras , Masculino , Microscopia de Contraste de Fase , Transplante de Neoplasias , Ductos Pancreáticos/patologia , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/ultraestrutura , RNA Mensageiro/análise , RNA Mensageiro/genética , Ratos , Ratos Endogâmicos F344 , Fator de Crescimento Transformador alfa/genética , gama-Glutamiltransferase/genética
13.
Health Phys ; 43(6): 875-89, 1982 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7152951

RESUMO

Control of radioactive waste disposal to the environment, based on the recommendations of the International Commission on Radiological Protection (ICRP), necessitates an identification of the critical group of members of the public exposed from a given practice. Criteria for identification of critical groups based mainly on ICRP recommendations are discussed. Methods existing up to 1974 are briefly reviewed in the light of these criteria. Two more recent methods are described and compared on the basis of previous data; these methods, which are complementary, are based on homogeneity considerations and satisfy the criteria generally rather better than do the earlier methods. The application of the newer techniques to recent surveys of fish and shellfish consumption in the coastal area of the North-East Irish Sea is described, in relation to discharges from the Windscale reprocessing plant. The results of this survey are presented, and estimates are given of the effective dose equivalent to members of these critical groups in recent years, to show the effect of liquid discharges from Windscale in terms of public radiation exposure.


Assuntos
Peixes , Contaminação Radioativa de Alimentos , Vigilância da População , Resíduos Radioativos , Esgotos , Frutos do Mar , Eliminação de Resíduos Líquidos , Animais , Humanos , Reino Unido
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