ERK signaling is required for eye-specific retino-geniculate segregation

In the mammalian visual system, retinal ganglion cell (RGC) projections from each eye, initially intermixed within the dorsal-lateral geniculate nucleus (dLGN), become segregated during the early stages of development, occupying distinct eye-specific layers. Electrical activity has been suggested to play a role in this process; however, the cellular mechanisms underlying eye-specific segregation are not yet defined. It is known that electrical activity is among the strongest activators of the extracellular signal-regulated kinase (ERK) pathway. Moreover, the ERK pathway is involved in the plasticity of neural connections during development. We examine the role of ERK in the segregation of retinal afferents into eye-specific layers in the dLGN. The activation of this signaling cascade was selectively blocked along the retino-thalamic circuitry by specific inhibitors, and the distribution of RGC fibers in the dLGN was studied. Our results demonstrate that the blockade of ERK signaling prevents eye-specific segregation in the dLGN, providing evidence that ERK pathway is required for the proper development of retino-geniculate connections. Of particular interest is the finding that ERK mediates this process both at the retinal and geniculate level.     

Plasma antioxidant enzymes and clastogenic factors as possible biomarkers of colorectal cancer risk

Oxidative damage plays an important role in the pathogenesis of colorectal (CR) cancer. This study investigated the activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione-S-transferase (GST) in plasma of 82 participants of a screening program for CR cancer prevention (30 females and 52 males; age 50-70 years). All subjects resulted positive to fecal occult blood test and were subsequently classified, according to the colonoscopy and histological findings, in patients with CR cancer, patients with colorectal polyps or controls. Furthermore, the activity of clastogenic factors (CFs) in plasma from study population was measured as the ability of inducing micronuclei (MN) in vitro in peripheral of a healthy donor. CAT and GR activities were significantly lower in CR cancer patients compared to controls (P<0.05) and polyps groups (P<0.05). SOD activity was significantly higher in patients with CR cancer than in polyp (P<0.05) and control (P<0.05) groups. GST activity was not significantly different in plasma of the three groups. An increase of CFs induction was observed in plasma of CR cancer patients (MN: 8.89±3.42) with respect to control (MN: 6.37±0.96 P<0.05). These results can contribute to define plasma biomarkers associated to oxidative stress damage that could predictive of CR cancer risk.     

Study of the surface morphology of a cholesteryl tethering system for lipidic bilayers

The immobilization of functional molecules embedded in lipidic membranes onto inorganic substrates is of great interest for numerous applications in the fields of biosensors and biomaterials. We report on the preparation and the morphological characterization of a tethering system for lipidic bilayers, which is based on cholesteryl derivatives deposited on hydrophilic surfaces by self-assembling and microcontact printing techniques. The investigation of the structural properties of the realized films by atomic, lateral, and surface potential microscopy allowed us to assess the high quality of the realized cholesteryl layers.     

每搏量变异度在围手术期容量治疗监测中的应用

每搏量变异度是动态的容量监测指标.机械通气患者心肺的相互作用是每搏量变异度的产生基础,通过动脉压力波形分析技术可以进行连续监测.每搏量变异度能够准确预测容量治疗反应,与静态的血流动力学参数相比,对于优化心输出量和组织氧供更有优势,但也存在一定的局限性.每搏量变异度受多种因素影响且不能用于自主呼吸和心律失常的患者.临床应用时应该综合考虑其影响因素,结合其他的指标和方法指导容量治疗.     

Calcium and secondary CPK signaling in plants in response to herbivore attack

Plant Ca²⁺ signals are involved in a sizable array of intracellular signaling pathways after pest invasion. Upon herbivore feeding there is a dramatic Ca²⁺ influx, followed by the activation of Ca²⁺-dependent signal transduction pathways that include interacting downstream networks of kinases for defense responses. Notably, Ca²⁺-binding sensory proteins such as Ca²⁺-dependent protein kinases (CPKs) have recently been documented to mediate the signaling following Ca²⁺ influx after herbivory, in phytohormone-independent manners. Here, we review the sequence of signal transductions triggered by herbivory-evoked Ca²⁺ signaling leading to CPK actions for defense responses, and discuss in a comparative way the involvement of CPKs in the signal transduction of a variety of other biotic and abiotic stresses.     

Cryptococcus neoformans var. grubii - Pathogenicity of environmental isolates correlated to virulence factors, susceptibility to fluconazole and molecular profile

The pathogenicity of Cryptococcus neoformans is heterogeneous and is associated with the expression of virulence factors. This study aimed to correlate the pathogenicity of C. neoformans var. grubii in BALB/c mice with in vitro virulence factors, fluconazole minimal inhibitory concentrations (MICs) and molecular profiles, before and after animal passage. Ten environmental isolates and one ATCC strain of C. neoformans var. grubii mating type α were evaluated. Most isolates (91%) killed 50% or more of the infected animals by day 24 postinfection and were recovered from the lungs and brains of surviving animals on days 7 and 14 postinfection. The burden of yeast in the lungs was more variable than that in the brain. The differences in the expression of virulence factors (growth at 37oC, presence and size of the capsule and production of melanin, urease, proteinase and phospholipase) by most isolates pre and postpassage in animals were not statistically significant. The fluconazole MICs in postpassaged lines differed by a one-dilution from the MIC of the corresponding prepassaged line for six isolates. Using molecular typing [polymerase chain reaction-fingerprinting with (GACA)4 and M13], eight isolates were identified as VNI and three as VNII. We concluded that different isolates with the same molecular and phenotypic profiles, including isolates that are markedly hypervirulent, span a wide range of virulence and there were no changes in virulence factors in the postpassaged lines when compared with the corresponding nonpassaged lines.