RESUMO
Effects of constant rearing temperature and the plant species fed upon by its hosts were investigated for several developmental parameters of Diadegma semiclausum (Hellén), an important parasitoid of the diamondback moth, Plutella xylostella (L.). Temperature had highly significant effects on all developmental parameters measured, and effects were usually both linear and quadratic with increasing temperature. Host plant species, comprising Brassica napus L., Brassica rapa L. ssp. pekinensis and Brassica oleracea L. var. capitata, also affected development of the parasitoid, and significant interactions were observed between plant species and rearing temperature for all developmental parameters measured. Development of D. semiclausum occurred successfully on all host plant species tested for the temperature range of 10 to 25°C. However, when its P. xylostella hosts consumed leaf tissue of B. napus, no specimens survived to pupate at 30°C, whilst pupation and adult eclosion occurred at 30°C on B. rapa ssp. pekinensis and B. oleracea var. capitata. At high ambient temperatures, such as those characteristic of tropical or subtropical regions (especially at low elevations) or regions that undergo temperature increases due to climate change, P. xylostella is predicted to occur at a higher range of temperatures than its biocontrol agent, D. semiclausum. Effects of high temperatures are expected to be more profound on the parasitoid for some host plants than others, with greater developmental limitations for the parasitoid on B. napus than on B. rapa or B. oleracea.
Assuntos
Brassica/parasitologia , Interações Hospedeiro-Parasita/fisiologia , Vespas/embriologia , Vespas/crescimento & desenvolvimento , Animais , Agentes de Controle Biológico , Brassica napus/parasitologia , Brassica rapa/parasitologia , Temperatura Alta , Larva , Mariposas/parasitologia , Mariposas/fisiologiaRESUMO
Insecticidal seed treatments are used commonly throughout the Northern Great Plains of North America to systemically protect seedlings of canola (Brassica napus L. and Brassica rapa L.) from attack by the flea beetles Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) (Coleoptera: Chrysomelidae). Here, we investigated differential responses by the two flea beetle species to the neonicotinoid seed treatments thiamethoxam (Helix and Helix XTra) and clothianidin (Prosper 400) in greenhouse experiments. P. cruciferae experienced higher mortality and fed less when exposed to these compounds than did P. striolata. Beetles of the overwintered and the summer generations responded differently when feeding on seedlings that developed with insecticidal seed treatments, with mortality higher for P. cruciferae in May than in August. When the two flea beetle species were held together at equal densities and allowed to feed on seedlings affected by the seed treatments, mortality of P. cruciferae significantly exceeded that of P. striolata. Differences in efficacies of these compounds for these beetles have ramifications for management strategies in regions where these insects occur sympatrically. Competitive release of P. striolata was previously reported to occur when P. cruciferae was excluded from brassicaceous crops; consequently, the consistent use of these seed treatments over millions of hectares of canola cropland may be a factor that contributes to a shift in prevalence of flea beetle pest species from P. cruciferae toward P. striolata.
Assuntos
Besouros , Guanidinas/farmacologia , Controle de Insetos/métodos , Inseticidas/farmacologia , Nitrocompostos/farmacologia , Oxazinas/farmacologia , Tiazóis/farmacologia , Animais , Brassica rapa/química , Brassica rapa/parasitologia , Besouros/classificação , Besouros/efeitos dos fármacos , Besouros/crescimento & desenvolvimento , Feminino , Masculino , Neonicotinoides , Estações do Ano , Sementes/química , Sementes/parasitologia , Especificidade da Espécie , TiametoxamRESUMO
While protection of autonomy is crucial to the practice of medicine, there is the persistent risk of a disconnect between the notion of self-determination and the need for a socially responsible medical system. An example of unbridled autonomy is the preferential use of costly medications without an appreciation of the impact of using these more expensive drugs on the resource pool of others. In the USA, costly medications of questionable incremental benefit are frequently prescribed with the complicity of both doctors and patients. Limiting self-determination in medication choices via an appreciation of the principle of justice reaches a better moral balance, while at the same time acknowledging the goals of doing good and avoiding harm in patient care.
Assuntos
Custos de Cuidados de Saúde/ética , Consentimento Livre e Esclarecido/ética , Autonomia Pessoal , Comportamento de Escolha , Meios de Comunicação/ética , Educação Médica Continuada/ética , Humanos , Relações Médico-Paciente/ética , Medição de Risco/ética , Responsabilidade SocialRESUMO
One of the central reactions in bodily energy metabolism is lipolysis in adipocytes, the reaction that governs the release of stored fatty acids from the adipocyte triacylglycerol pool, which constitutes the major energy reserve in animals. These fatty acids are then transported by serum albumin to various tissues to supply their energy requirements. This reaction was previously thought to result from phosphorylation and activation of hormone-sensitive lipase by protein kinase A (PKA) but is now known to be governed by a translocation of the lipase from the cytosol to the surface of the intracellular lipid droplet that houses the reservoir of TAG. This droplet is coated with perilipin A, which is also phosphorylated by PKA in response to lipolytic stimuli, and phosphorylation of perilipin A is essential for HSL translocation and stimulated lipolysis.
Assuntos
Adipócitos/metabolismo , Proteínas de Ligação a DNA/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Metabolismo dos Lipídeos , Proteínas de Membrana/fisiologia , Fosfoproteínas/fisiologia , Proteínas da Gravidez/fisiologia , Células 3T3 , Animais , Proteínas de Transporte , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Humanos , Camundongos , Perilipina-1 , Perilipina-2 , Perilipina-3 , Fosfoproteínas/genética , Esterol Esterase/metabolismo , Proteínas de Transporte VesicularRESUMO
Perilipin coats the lipid droplets of adipocytes and is thought to have a role in regulating triacylglycerol hydrolysis. To study the role of perilipin in vivo, we have created a perilipin knockout mouse. Perilipin null (peri(-/-)) and wild-type (peri(+/+)) mice consume equal amounts of food, but the adipose tissue mass in the null animals is reduced to approximately 30% of that in wild-type animals. Isolated adipocytes of perilipin null mice exhibit elevated basal lipolysis because of the loss of the protective function of perilipin. They also exhibit dramatically attenuated stimulated lipolytic activity, indicating that perilipin is required for maximal lipolytic activity. Plasma leptin concentrations in null animals were greater than expected for the reduced adipose mass. The peri(-/-) animals have a greater lean body mass and increased metabolic rate but they also show an increased tendency to develop glucose intolerance and peripheral insulin resistance. When fed a high-fat diet, the perilipin null animals are resistant to diet-induced obesity but not to glucose intolerance. The data reveal a major role for perilipin in adipose lipid metabolism and suggest perilipin as a potential target for attacking problems associated with obesity.
Assuntos
Adipócitos/metabolismo , Leptina/biossíntese , Obesidade/metabolismo , Fosfoproteínas/fisiologia , Adipócitos/citologia , Tecido Adiposo/metabolismo , Animais , Glicemia/análise , Proteínas de Transporte , Diferenciação Celular , Gorduras na Dieta/metabolismo , Feminino , Lipólise , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Consumo de Oxigênio , Peptídeos/metabolismo , Perilipina-1 , Perilipina-2 , Fosfoproteínas/genética , Esterol Esterase/metabolismo , Magreza , Triglicerídeos/metabolismoRESUMO
The incidence of pancreatic cancer has increased threefold over the last 40 years with the greatest rate of growth occurring in the elderly. In the past it was suggested that elderly patients tolerated pancreaticoduodenectomy less well than younger patients with higher mortality rates. This single-institution experience examines the question of whether age is a significant factor in relation to morbidity and mortality in patients undergoing pancreaticoduodenectomy. Between 1994 and 1999 outcomes of 122 patients who underwent pancreaticoduodenectomy were reviewed. There were 48 patients 70 years of age and older and 74 patients less than 70 years of age. Both groups were compared with respect to preoperative clinical prognostic determinates and perioperative factors affecting morbidity and mortality. There was no significant difference between the two groups comparing their comorbidities, use of preoperative antibiotics, intraoperative blood loss, or length of hospital stay (11.9 and 10.8 days respectively). The two groups were also similar with regard to pathologic diagnosis with pancreatic adenocarcinoma being the most frequently encountered neoplasm. There was one death in the less-than-70-year-old group and none in the older group. No significant difference in the rate of complications was appreciated. These data demonstrate that pancreaticoduodenectomy can be performed safely in patients 70 years of age and older with morbidity and mortality rates similar to those of younger individuals.
Assuntos
Adenocarcinoma/cirurgia , Idoso , Colangiocarcinoma/cirurgia , Neoplasias Pancreáticas/cirurgia , Pancreaticoduodenectomia , Pancreatite/cirurgia , Seleção de Pacientes , Adenocarcinoma/complicações , Adenocarcinoma/patologia , Adulto , Fatores Etários , Idoso de 80 Anos ou mais , Colangiocarcinoma/complicações , Colangiocarcinoma/patologia , Comorbidade , Contraindicações , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Morbidade , Neoplasias Pancreáticas/complicações , Neoplasias Pancreáticas/patologia , Pancreaticoduodenectomia/efeitos adversos , Pancreaticoduodenectomia/mortalidade , Pancreatite/complicações , Pancreatite/patologia , Prognóstico , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Hepatic lipase (HL) hydrolysis of phosphatidylcholine (PC) was studied in recombinant high-density lipoprotein particles (r-HDL). r-HDL were made from cholate mixed micelles that contained PC, apo AI, and, in some cases, unesterified cholesterol. r-HDL were characterized using chemical composition, nondenaturing gradient gel electrophoresis, transmission electron microscopy, and dynamic light scattering. The r-HDL were found to be discoidal and in the size range of native HDL. Upon treatment of cholesterol-containing r-HDL with lecithin-cholesterol acyltransferase (LCAT), to form cholesteryl ester, the discoidal r-HDL became spheroidal. The effects of r-HDL morphology and size on HL activity were studied on r-HDL made of palmitoyloleoyl-PC, unesterified cholesterol, cholesteryl ester, and apolipoprotein AI. Spheroidal r-HDL were hydrolyzed at a faster rate than discoidal r-HDL. Protein-poor r-HDL were hydrolyzed by HL at a faster rate than protein rich r-HDL. Unesterified cholesterol had no apparent effect on particle PC hydrolysis. The hydrolysis of different species of PC [dipalmitoyl (DPPC), dioleoyl(DOPC), palmitoylarachidonoyl (PAPC), and palmitoyloleoyl (POPC)] in r-HDL was also investigated. In discoidal r-HDL, we found that POPC >/= DOPC = PAPC/DPPC. However, in LCAT-treated spheroidal r-HDL, POPC = DOPC > PAPC/DPPC. In both discoidal and spheroidal rHDL, DPPC containing r-HDL were not hydrolyzed to a significant extent. Collectively, these studies demonstrate that the physico-chemical properties of particles (such as phospholipid packing and phospholipid acyl composition) play a significant role in hydrolysis of HDL phospholipid by HL and, therefore, in reverse cholesterol transport.
Assuntos
Lipase/metabolismo , Lipoproteínas HDL/metabolismo , Fígado/enzimologia , Fosfatidilcolinas/metabolismo , Proteínas Recombinantes/metabolismo , Apolipoproteína A-I/metabolismo , Ésteres do Colesterol/química , Ésteres do Colesterol/metabolismo , Humanos , Hidrólise , Lasers , Lipoproteínas HDL/química , Lipoproteínas HDL/ultraestrutura , Microscopia Eletrônica , Tamanho da Partícula , Fosfatidilcolina-Esterol O-Aciltransferase/metabolismo , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/ultraestrutura , Espalhamento de Radiação , Especificidade por SubstratoRESUMO
We analyzed monopolar recordings obtained from a brain area implicated in the implementation of conscious intention--the Supplementary Motor Area. Other monopolar recordings were taken at F3, F4, C3, C4, P3, P4, O1, O2, F7, F8, T3, T4, T5, T6, and Cz using the standard international (10/20) pattern with linked ears as reference. Using on line fast-fourier transforms of brainwave signals and computer displays with one-second updates of 1Hz wide brainwave bands of 5, 7, 10, 12, 14, 16, 20 and 28 Hz, specific brainwave signatures were identified for attentional, cognitive, imaginal, and somatosensory states. This first, and thus limited, cartography of consciousness is discussed in light of the cognitive descriptions clinically ascribed to the commonly used brainwave frequency bands designated as Delta, Theta, Alpha, and Beta.
Assuntos
Estado de Consciência/fisiologia , Eletroencefalografia , Adolescente , Adulto , Criança , Cognição , Imagem Eidética , Eletrodos , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
The growth of Demel human metastatic melanoma cells was inhibited by 12-O-tetradecanoylphorbol-13-acetate (TPA) and other nonphorbol tumor promoters including palytoxin and okadaic acid. Using flow cytometry, we have demonstrated that the cells arrested growth in G1 and G2 phases of the cell cycle. Detailed analysis of the kinetics of the growth arrest in unsynchronized cells showed that (a) the growth arrest was transient and peaked 16-20 h following addition of TPA; (b) effects of TPA on cell growth began within 1-2 h after the addition; and (c) cells completed S phase and arrested in G2. In addition, TPA induced a pronounced morphological change, which peaked by 1 h and gradually subsided over 24 h. In populations of cells synchronized in G1 using lovastatin, (a) addition of TPA blocked the onset of DNA synthesis up to the end of G1; (b) the lag between addition of the drug and onset of DNA synthesis was less than 30 min; and (c) addition of TPA at the end of G1 prevented the increased phosphorylation of p34cdc2, as determined by immunoprecipitation. The experiments reported here show that TPA transiently blocked the proliferation of Demel melanoma cells at the G1-S border and in G2, thus preventing cells from progressing through the cell cycle. These experiments suggest that pathways involving protein kinase C interact with and rapidly alter the molecular pathways involving p34cdc2 which regulate the onset of DNA synthesis and the G2-M transition.
Assuntos
Proteína Quinase CDC2/metabolismo , Interfase/efeitos dos fármacos , Melanoma/secundário , Proteínas de Neoplasias/metabolismo , Acetato de Tetradecanoilforbol/farmacologia , Neoplasias da Mama/secundário , Divisão Celular/efeitos dos fármacos , Replicação do DNA/efeitos dos fármacos , Depressão Química , Humanos , Masculino , Pessoa de Meia-Idade , Fosforilação/efeitos dos fármacos , Proteína Quinase C/fisiologia , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismo , Células Tumorais Cultivadas/patologiaAssuntos
Melanoma/patologia , Ésteres de Forbol/farmacologia , Ciclo Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Humanos , Melanócitos/citologia , Melanócitos/efeitos dos fármacos , Melanoma/secundário , Acetato de Tetradecanoilforbol/farmacologia , Transcrição Gênica/efeitos dos fármacos , Células Tumorais CultivadasRESUMO
The primary event in the pathogenesis of severe malaria in Plasmodium falciparum infection is thought to be adherence of trophozoite- and schizont-infected erythrocytes to capillary endothelium, a process called sequestration. Identifying the endothelial molecules used as receptors is an essential step in understanding this disease process. Recent work implicates the membrane glycoprotein CD36 (platelet glycoprotein IV; refs 2-5) and the multi-functional glycoprotein thrombospondin as receptors. Although CD36 has a widespread distribution on microvascular endothelium, it may not be expressed on all capillary beds where sequestration occurs, especially in the brain. The role of thrombospondin in cell adhesion, in vitro or in vivo, is less certain. We have noticed that some parasites bind to human umbilical-vein endothelial cells independently of CD36 or thrombospondin. To screen for alternative receptors, we have developed a novel cell-adhesion assay using transfected COS cells, which confirms that CD36 is a cell-adhesion receptor. In addition, we find that an endothelial-binding line of P. falciparum binds to COS cells transfected with a complementary DNA encoding intercellular adhesion molecule-1. As this molecule is widely distributed on capillaries and is inducible, this finding may be relevant to the pathogenesis of severe malaria.