RESUMO
[1] Independent data from the Gulf of Mexico are used to develop and test the hypothesis that the same sequence of physical and ecological events each year allows the toxic dinoflagellate Karenia brevis to become dominant. A phosphorus-rich nutrient supply initiates phytoplankton succession, once deposition events of Saharan iron-rich dust allow Trichodesmium blooms to utilize ubiquitous dissolved nitrogen gas within otherwise nitrogen-poor sea water. They and the co-occurring K. brevis are positioned within the bottom Ekman layers, as a consequence of their similar diel vertical migration patterns on the middle shelf. Upon onshore upwelling of these near-bottom seed populations to CDOM-rich surface waters of coastal regions, light-inhibition of the small red tide of ~1 ug chl l(-1) of ichthytoxic K. brevis is alleviated. Thence, dead fish serve as a supplementary nutrient source, yielding large, self-shaded red tides of ~10 ug chl l(-1). The source of phosphorus is mainly of fossil origin off west Florida, where past nutrient additions from the eutrophied Lake Okeechobee had minimal impact. In contrast, the P-sources are of mainly anthropogenic origin off Texas, since both the nutrient loadings of Mississippi River and the spatial extent of the downstream red tides have increased over the last 100 years. During the past century and particularly within the last decade, previously cryptic Karenia spp. have caused toxic red tides in similar coastal habitats of other western boundary currents off Japan, China, New Zealand, Australia, and South Africa, downstream of the Gobi, Simpson, Great Western, and Kalahari Deserts, in a global response to both desertification and eutrophication.
RESUMO
To evaluate the impact of chemotherapy and surgery on the outcome of osteosarcoma (OS) of the extremities and to identify prognostic factors in Brazilian patients. A total of 225 patients with metastatic and nonmetastatic OS of the extremities were enrolled and assessed in two consecutive studies designed and implemented by the Brazilian Osteosarcoma Treatment Group. The 5-year survival and event-free survival rates for the 209 assessable patients were 50.1% and 39%, respectively; for the 178 patients with nonmetastatic disease at diagnosis, the rates were 60.5% and 45.5%, respectively. The multivariate analysis showed that the following variables were associated with a shorter survival: metastases at diagnosis (P < .001), necrosis grades 1 and 2 (P = .046), and tumor size (P = .0071). The overall 5- and 10-year survival rates were lower than the rates reported in North American and European trials. A pattern of advanced disease at diagnosis was often present, with a high proportion of patients having metastases (20.8%) and large tumor size (42.9%). However, these features were not necessarily associated with longer duration of prediagnostic symptoms. These findings were considered in the strategic planning of the current Brazilian cooperative study, with the aim of improving survival and quality of life of a large number of patients with OS.
Assuntos
Humanos , Estudos de Casos e Controles , Metástase Neoplásica , Osteossarcoma/diagnóstico , Osteossarcoma/tratamento farmacológicoRESUMO
The authors studied 30 cases of aortic dissection performed from January 1978 to December 1987. Dissection was classified as type A (intimal tear beginning in the ascending aorta or arch) and type B (intimal tear beginning in the descending aorta). Type A predominated (66.7%). Type B dissection was most frequent in patients older than 60. Precordial pain was the main symptom in type A cases, whereas 62.5% of type B cases showed no precordial pain. Most frequent findings in type A patients were hypotension (45.5%), murmur of aortic regurgitation (40.0%), and dyspnea (40.0%), whereas in type B patients, most frequent findings were hypertension (28.6%), and pulse deficit (42.9%). The major differential diagnosis for type A was myocardial infarction (43.8%), and for type B, peripheral artery failure (25.0%) and acute pneumonia (25.0%). 24 patients (80.0%) had hemorrhage. Hemorrhage into the pericardial sac occurred in 68.8% of type A patients, and 50.0% of type B patients had retroperitoneal hemorrhage. Systemic hypertension, atherosclerosis, medial cystic necrosis and endocrine disorders were considered predisposing factors for both type of dissection. A case of dissection after aortic valve replacement associated with ascending aorta tubular graft replacement was observed in this series. In type A patients, average survival was 6.3 days, and in type B, 11.1 days. The major cause of death was hemorrhage (70.0%).
Assuntos
Aneurisma Aórtico/patologia , Dissecção Aórtica/patologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Dissecção Aórtica/complicações , Dissecção Aórtica/fisiopatologia , Aneurisma Aórtico/complicações , Aneurisma Aórtico/fisiopatologia , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , PrognósticoRESUMO
E apresentado um caso de insulinoma em doente idosa, com historia de dez anos de evolucao. O diagnostico clinico foi confirmado pela determinacao da relacao insulina/glicemia de jejum, ultrasonografia e tomografia computadorizada. O tumor era grande, localizado na regiao cefalica do pancreas, tendo sido enucleado. Sao discutidos os diferentes aspectos clinicos e cirurgicos dos tumores pancreaticos produtores de insulina
Assuntos
Idoso , Humanos , Feminino , Hipoglicemia , Insulinoma , Neoplasias Pancreáticas , PancreatectomiaRESUMO
Os autores apresentam caso de crianca de 5 meses, com desnutricao grave e quadro de frequente pneumonia de repeticao, submetida a intensa antibioticoterapia. A autopsia revelou endocardite por Candida sp., formando trombo de grandes proporcoes, ocluindo totalmente a cavidade ventricular direita. O fungo foi identificado por tecnicas de anticorpos fluorescentes, aliadas a hemoculturas e cultura de LCR positivas para Candida sp. Histologicamente formava graos semelhantes ao dos micetomas. Este comportamento tecidual nao e usual na candidiase e, segundo a literatura, por nos consultada, trata-se de caso unico que assim se apresenta
Assuntos
Candidíase , Endocardite , TromboseAssuntos
Neoplasias Intestinais , Neoplasias de Tecido Vascular , Adulto , Idoso , Neoplasias do Ceco/patologia , Ceco/patologia , Feminino , Humanos , Íleo/patologia , Neoplasias Intestinais/patologia , Masculino , Pessoa de Meia-Idade , Neoplasias de Tecido Vascular/patologia , Neoplasias Retais/patologia , Reto/patologiaRESUMO
The concentration of radon-222 in air was measured during a flight from Miami to Barbados to Dakar and return; concentrations ranged from 1 to 55 picocuries per standard cubic meter of air and were highest in areas of dense haze, which were present along most of the flight path across the Atlantic Ocean. The haze is attributed to dust originating from the arid regions of western Africa. Radon-222 may be useful as a tracer for African air parcels over the equatorial Atlantic.