HLA Class II Defects in Burkitt Lymphoma: Bryostatin-1-Induced 17 kDa Protein Restores CD4+ T-Cell Recognition

While the defects in HLA class I-mediated Ag presentation by Burkitt lymphoma (BL) have been well documented, CD4+ T-cells are also poorly stimulated by HLA class II Ag presentation, and the reasons underlying this defect(s) have not yet been fully resolved. Here, we show that BL cells are deficient in their ability to optimally stimulate CD4+ T cells via the HLA class II pathway. The observed defect was not associated with low levels of BL-expressed costimulatory molecules, as addition of external co-stimulation failed to result in BL-mediated CD4+ T-cell activation. We further demonstrate that BL cells express the components of the class II pathway, and the defect was not caused by faulty Ag/class II interaction, because antigenic peptides bound with measurable affinity to BL-associated class II molecules. Treatment of BL with broystatin-1, a potent modulator of protein kinase C, led to significant improvement of functional class II Ag presentation in BL. The restoration of immune recognition appeared to be linked with an increased expression of a 17 kDa peptidylprolyl-like protein. These results demonstrate the presence of a specific defect in HLA class II-mediated Ag presentation in BL and reveal that treatment with bryostatin-1 could lead to enhanced immunogenicity

Influência da posição da estaca no ramo ortotrópico na propagação de dois genótipos de Coffea Canephora Pierre irrigados pelo método de microaspersão por nebulização.

O uso de mudas de qualidade é fundamental para assegurar a produtividade das lavouras de café conilon. O uso de estacas provenientes de ramos ortotrópicos é a alternativa mais utilizada. Porém, ainda permanecem questões que devem ser investigadas, relativasa o processo de propagação, pois fatores exógenos e endógenos podem limitar a brotação, mesmo quando as condições sejam favoráveis para este processo. Assim, objetivou-se avaliar a produção de mudas e a taxa fotossintética, a partir de estacas provenientes de três diferentes posições no ramo ortotrópico, ápice, meio e base do ramo ortotrópico em dois genótipos de café conilon (12V e 748). Determinou-se a taxa fotossintética líquida (A-?mol CO2m-2s-1) aos 0, 13, 26 e 39 dias após o plantio das estacas (DAP) e o porcentual de estacas enraizadas e de estacas com brotaçãoque emitiram raiz aos 39 DAP. As curvas ajustadas pela equação de regressão não linear para a taxa fotossintética líquida indica um padrão de aclimatação e recuperação durante a produção de mudas. Não houve influência dos fatores genótipo e posição do ramo na fotossíntese. O genótipo 748 e os terços mediano e basaldo ramo ortotrópico apresentaram melhor enraizamento

Beyond oxygen: complex regulation and activity of hypoxia inducible factors in pregnancy

In the first trimester the extravillous cytotrophoblast cells occlude the uterine spiral arterioles creating a low oxygen environment early in pregnancy, which is essential for pregnancy success. Paradoxically, shallow trophoblast invasion and defective vascular remodelling of the uterine spiral arteries in the first trimester may result in impaired placental perfusion and chronic placental ischemia and hypoxia later in gestation leading to adverse pregnancy outcomes. The hypoxia inducible factors (HIFs) are key mediators of the response to low oxygen. We aimed to elucidate mechanisms of regulation of HIFs and the role these may play in the control of placental differentiation, growth and function in both normal and pathological pregnancies. The Pubmed database was consulted for identification of the most relevant published articles. Search terms used were oxygen, placenta, trophoblast, pregnancy, HIF and hypoxia. The HIFs are able to function throughout all aspects of normal and abnormal placental differentiation, growth and function; during the first trimester (physiologically low oxygen), during mid-late gestation (where there is adequate supply of blood and oxygen to the placenta) and in pathological pregnancies complicated by placental hypoxia/ischemia. During normal pregnancy HIFs may respond to complex alterations in oxygen, hormones, cytokines and growth factors to regulate placental invasion, differentiation, transport and vascularization. In the ever-changing environment created during pregnancy, the HIFs appear to act as key mediators of placental development and function and thereby are likely to be important contributors to both normal and adverse pregnancy outcomes

Quasi Z-source Network Based Control Scheme for Fstp Bldc Motor

The paper proposes a novel four switch three phase BLDC motor control scheme which boosts the voltage level, extends the range of speed as well as reduces output torque ripple. The additionally partial circuits of quasi Z-source network and the bridge arm of four-switch inverter constitute the quasi Z-source converter. During the operation of motor, shoot through states are inserted. Then the input voltage of inverter increases and the performance of motor can be markedly improved. The dynamic performance of current is influenced and the speed is limited, for the irregular dc-link voltage utilization in the control of four-switch three-phase (FSTP) BLDC motor. This project presents a novel topology, which combines quasi Z-source converter and FSTP drive circuit. The drawbacks of FSTP BLDC motor are analyzed, the control methods of each mode in quasi Z-source four-switch three-phase (QZFSTP) topology are illustrated. Simulations for QZFSTP BLDC motor were constructed in MATLAB/Simulink circumstance. We can provide an alternate strategy to control BLDC motor by using Four Switch Three Phase inverter. FSTPI helps reduction in switching losses, gate drive requirements, circuit cost and computational time. At low power application, FSTPI fed BLDC motor drives are more suitable than SSTPI (Six Switch Three Phase Inverter). Also reconfiguration of these three leg inverter to FSTPI, in case of switch or leg failure can be done. In proposed system losses are minimizing due to FSTPI because there is reduction in switching losses and also due to Quasi Z-source Inverter output voltage is boosting hence output results were better. To overcome the ripple in torque and distortion in current the QZFSTP BLDC motor control scheme is proposed

H�bitos alimentarios e interacciones tr�ficas de Anisotremus interruptus (Pisces: Haemulidae) y Lutjanus argentiventris (Pisces: Lutjanidae) en el Pac�fico Central Mexicano

Se obtuvieron est�magos de ejemplares adultos de Anisotremus interruptus y Lutjanus argentiventris para conocer los componentes alimentarios de cada especie y sus interacciones tr�ficas durante un periodo de surgencia en el Pac�fico Central Mexicano. Se identificaron 79 tipos de presas agrupadas en 15 categor�as alimentarias. La dieta de A. interruptus est� constituida principalmente de microinvertebrados (anf�podos y larvas de crust�ceos), holot�ridos y ofiuros. L. argentiventris se alimenta de macroinvertebrados (camarones, cangrejos y estomat�podos), peces y cefal�podos. Ambas especies presentan una estrategia alimentaria generalista y una superposici�n tr�fica baja. La dieta de estas especies est� relacionada con la apertura de la boca