Differential effects of US2, US6 and US11 human cytomegalovirus proteins on HLA class Ia and HLA-E expression: impact on target susceptibility to NK cell subsets

We compared in an inducible expression system the individual effect of US2, US6 and US11 human cytomegalovirus (HCMV) proteins on HLA-E and HLA class Ia surface expression, assessing in parallel their influence on target susceptibility to NK cell clones. To this end, the RPMI 8866 B lymphoma cell line (HLA-A2, HLA-A3, HLA-B7, HLA-Cw7, HLA-E(R), HLA-E(G)) was stably cotransfected with the ecdysone receptor, together with the US sequences under the control of an ecdysone-inducible promoter. Biosynthesis of viral proteins was turned on by incubating transfectants with Ponasterone A. US6 down-regulated expression of all class I molecules, hampering target resistance to NK cell clones controlled by the CD94/NKG2A, KIR2DL2 and/or CD85j (ILT2 or LIR-1) inhibitory receptors. By contrast, US11 reduced the surface levels of class Ia molecules but preserved HLA-E; this rendered US11(+) cells sensitive to NK clones under the control of KIR2DL2 and/or CD85j, while their resistance to CD94/NKG2A(+)KIR2DL2(-) effector cells was maintained. US2 preserved as well HLA-E expression but selectively targeted class Ia molecules; in fact, HLA-A and HLA-C allotypes were down-modulated whereas HLA-B7 remained unaltered. US2(+) targets became sensitive to KIR2DL2(+) cells but remained resistant to CD94/NKG2A(+)CD85j(+) NK clones. The differential effects of US proteins on HLA class Ia and HLA-E likely reflect the evolutionary adaptation of HCMV to counteract NK-mediated surveillance.     

Fiber-enriched double-setting calcium phosphate bone cement

Calcium phosphate bone cements are useful in orthopedics and traumatology, their main advantages being their biocompatibility and bioactivity, which render bone tissue osteoconductive, providing in situ hardening and easy handling. However, their low mechanical strength, which, in the best of cases, is equal to the trabecular bone, and their very low toughness are disadvantages. Calcium phosphate cement compositions with mechanical properties more closely resembling those of human bone would broaden the range of applications, which is currently limited to sites subjected to low loads. This study investigated the influence of added polypropylene, nylon, and carbon fibers on the mechanical properties of double setting alpha-tricalcium phosphate-based cement, using calcium phosphate cement added to an in situ polymerizable acrylamide-based system recently developed by the authors. Although the addition of fibers was found to reduce the compression strength of the double-setting calcium phosphate cement because of increased porosity, it strongly increased the cement's toughness (J(IC)) and tensile strength. The composites developed in this work, therefore, have a potential application in shapes subjected to flexure.     

Sleep patterns in Spanish adolescents: associations with TV watching and leisure-time physical activity

We aimed to describe the sleep patterns in Spanish adolescents and to examine the relationships of sleep duration and morning tiredness with participation in leisure-time physical-sporting activities (LT-PA) and television (TV) watching. Sleep duration, morning tiredness, participation in LT-PA and time spent on watching TV were reported by 2,179 (1,139 females) Spanish adolescents (AVENA study). Data were analyzed by binary logistic regression. One-fifth of the adolescents reported insufficient night sleep (<8 h) on school days. The review of the literature (30 studies) showed that the Spanish adolescents sleep as long as adolescents from central Europe, and longer than those from other Mediterranean countries, South Africa, Asia and North America. Insufficient sleep duration doubled the odds of excessive TV watching (≥3 h/day) in males, regardless of morning tiredness (OR 2.15, 95% CI 1.42–3.27). Morning tiredness reduced the odds of participating in any LT-PA in both males and females (0.49, 0.34–0.70 and 0.49, 0.35–0.69, respectively), and increased the odds of excessive TV watching in females, regardless of sleep duration (2.49, 1.64–3.79). We conclude that non-participation in LT-PA is associated with morning tiredness in male and female adolescents, while excessive TV watching is more associated with short sleep or morning tiredness depending on gender.     

Complex network analysis of human ECoG data

Localization of the epileptogenic zone (EZ) is an important issue in epileptology, even though there is not a unique definition of the epileptic focus. By using complex network analysis of electrocorticographic (ECoG) data we identify three singular areas in the temporal lobe of epileptic patients, the node with highest local synchronization power, the most connected node, and the node with highest interactions load. Connectivity in the data is extracted from the Minimum Spanning Tree (MST) of global correlations. We address the question whether removal of these nodes during the surgery is crucial in the suppression or reduction in the quantity of post-operative seizures. From five ECoG records, local areas with high synchronization power appear to be significantly involved in the development of epileptic seizures. The other two areas seem not to be fundamental in the seizures onset and development. Moreover, the approach proposed shed new light in cortical connectivity patterns in the human temporal lobe. All the analyzed records are during the inter-ictal state.     

Acanthamoeba interactions with human brain microvascular endothelial cells

Acanthamoeba are opportunistic protozoan parasites that can cause fatal granulomatous amoebic encephalitis, however, the pathogenic mechanisms associated with this disease remain unclear. One of the primary factors in Acanthamoeba encephalitis is the haematogenous spread, followed by invasion of the blood-brain barrier resulting in the transmigration of Acanthamoeba into the central nervous system. In this study, we have used human brain microvascular endothelial cells, which constitute the blood-brain barrier and studied their interactions with Acanthamoeba. Using in vitro cultures, we showed that Acanthamoeba isolates belonging to genotypes T3, T4 and T11, exhibited increased cytotoxicity on human brain microvascular endothelial cells as well as exhibited higher binding and were considered potential pathogens. In contrast, Acanthamoeba isolates belonging to genotypes T2 and T7 exhibited minimal cytotoxicity and significantly less binding to human brain microvascular endothelial cells (P< 0.01). Furthermore, exogenous alpha-mannose inhibited binding but increased cytotoxicity of human brain microvascular endothelial cells. This is the first demonstration of Acanthamoeba interactions with primary human brain microvascular endothelial cells.     

Relative importance of CD4+ and CD8+ T cells in the resolution of Chlamydophila abortus primary infection in mice

The role of the specific cellular immune response is well established in Chlamydiaceae infections, but the importance of each T-cell subset seems to be species-dependent. This study was designed to clarify the role of T-cell subsets in the response to Chlamydophila abortus primary infection. C57BL/6 mice were depleted of CD4+ or CD8+, or both, by monoclonal antibody injections and subsequently infected with C. abortus. Mice were killed at intervals and samples were collected for bacteriological and histopathological analysis. Also carried out were spleen cell culture, cytokine quantification, immunolabelling for C. abortus antigen, and a TUNEL assay for apoptosis. CD8+ T cell-depleted mice all died within 12 days of C. abortus infection, while no mortality was observed in the other groups; surprisingly, CD4+ T cell-depleted mice showed lower morbidity (expressed as weight loss) than did a non-depleted (control) group. CD8+ T cell-depleted mice also differed from the other groups in showing a significantly higher chlamydial burden in the liver. CD8+ T cell-depleted mice also had a higher number of apoptotic cells in hepatic inflammatory foci and showed exacerbated IFN-gamma production by spleen cells after specific stimulation. Simultaneous depletion of both T-cell subpopulations led to a chronic infection, but not to early mortality. It is concluded that CD8+ T cells may play a role in the regulatory control of the CD4+ T-cell response and may have a direct cytotoxic or IFN-gamma-mediated effect on infected cells.     

Inhibition of the intrinsic factor X activating complex by protein S: evidence for a specific binding of protein S to factor VIII

Protein S is a vitamin K-dependent nonenzymatic anticoagulant protein that acts as a cofactor to activated protein C. Recently it was shown that protein S inhibits the prothrombinase reaction independent of activated protein C. In this study, we show that protein S can also inhibit the intrinsic factor X activation via a specific interaction with factor VIII. In the presence of endothelial cells, the intrinsic activation of factor X was inhibited by protein S with an IC50 value of 0.28 +/- 0.04 mumol/L corresponding to the plasma concentration of protein S. This inhibitory effect was even more pronounced when the intrinsic factor X activation was studied in the presence of activated platelets (IC50 = 0.15 +/- 0.02 mumol/L). When a nonlimiting concentration of phospholipid vesicles was used, the plasma concentration of protein S (300 nmol/L) inhibited the intrinsic factor X activation by 40%. Thrombin-cleaved protein S inhibited the endothelial cell-mediated factor X activation with an IC50 similar to that of native protein S (0.26 +/- 0.02 mumol/L). Protein S in complex with C4b-binding protein inhibited the endothelial cell-mediated factor X activation more potently than protein S alone (IC50 = 0.19 +/- 0.03 mumol/L). Using thrombin activated factor VIII, IC50 values of 0.53 +/- 0.09 mumol/L and 0.46 +/- 0.10 mumol/L were found for native protein S and thrombin-cleaved protein S, respectively. The possible interactions of protein S with factor IXa, phospholipids, and factor VIII were investigated. The enzymatic activity of factor IXa was not affected by protein S, and interaction of protein S with the phospholipid surface could not fully explain the inhibitory effect of protein S on the factor X activation. Using a solid-phase binding assay, we showed a specific, saturable, and reversible binding of protein S to factor VIII with a high affinity. The concentration of protein S where half-maximal binding was reached (B1/2max) was 0.41 +/- 0.06 mumol/L. A similar affinity was found for the interaction of thrombin-cleaved protein S with factor VIII (B1/2max = 0.40 +/- 0.04 mumol/L). The affinity of the complex protein S with C4B-binding protein appeared to be five times higher (B1/2max = 0.07 +/- 0.03 mumol/L). Because the affinities of the interaction of the different forms of protein S with factor VIII correspond to the IC50 values observed for the intrinsic factor X activating complex, the interaction of protein S with factor VIII may explain the inhibitory effect of protein S on the intrinsic factor X activating complex.(ABSTRACT TRUNCATED AT 400 WORDS)     

Calendario de vacunaciones de la Asociación Española de Pediatría: recomendaciones 2012

The Advisory Committee on Vaccines of the Spanish Association of Pediatrics (CAV-AEP) updates the immunization schedule every year, taking into account epidemiological data as well as evidence on the effectiveness and efficency of vaccines.The present schedule includes grades of recommendation. We have graded as routine vaccinations those that the CAV-AEP believes all children should receive; as recommended those that fit the profile for universal childhood immunization and would ideally be given to all children, but that can be prioritized according to the resources available for their public funding; and as risk group vaccinations those that specifically target individuals in situations of risk. Immunization schedules tend to be dynamic and adaptable to ongoing epidemiological changes. Nevertheless, the achievement of a unified immunization schedule in all regions of Spain is a top priority for the CAV-AEP.Based on the latest epidemiological trends, the main changes introduced to the schedule are the administration of the first dose of the MMR and the varicella vaccines at age 12 months (12–15 months) and the second dose at age 2–3 years, as well as the administration of the Tdap vaccine at age 4–6 years, always followed by another dose at 11–14 years of age.The CAV-AEP believes that the coverage of vaccination against human papillomavirus in girls aged 11–14 years must increase. It reasserts its recommendation to include vaccination against pneumococcal disease in the routine immunization schedule. Universal vaccination against varicella in the second year of life is an effective strategy and therefore a desirable objective. Vaccination against rotavirus is recommended in all infants due to the morbidity and elevated healthcare burden of the virus. The Committee stresses the need to vaccinate population groups considered at risk against influenza and hepatitis A. Finally, it emphasizes the need to bring incomplete vaccinations up to date following the catch-up immunization schedule.     

Urinary tract infections: antibiotic resistance and clinical follow up

The initial treatment of the urinary tract infections (UTI) is empirical and it is a priority to determine the antibiotic resistance of most common germs in a population. Furthermore, due to the suspicion of acute pyelonephritis the presence of renal scarring should be ruled out as this may lead to further complications. A retrospective longitudinal study was performed on all children under 14 years diagnosed with UTI from January 1 2009 to December 31 2009. The in vitro susceptibility to the most important urinary pathogens was analysed, along with the presence of scars, and a subsequent follow-up. The most frequently isolated bacteria were E. coli (80%), P. mirabilis (9.7%) and K. pneumoniae (4.2%). In the antibiogram, E coli showed a high sensitivity to fosfomycin (99.1%), cefotaxime (98.2%) cefuroxime (97.3%) and gentamicin (95.6%). The sensitivity obtained against amoxicillin-clavulanate was 83.2%, while that obtained against cotrimoxazole was 78.9%. Post-pyelonephritis scars were found in 19% of patients with febrile UTI, 17% out-patients and 20% of those admitted.