A novel pediatric biventricular assist device: in vitro test results.

Most ventricular assist devices (VADs) currently used in infants are extracorporeal. These VADs require long-term anticoagulation therapy and extensive surgery, and two devices are needed for biventricular support. We designed a biventricular assist device based on shape memory alloy that reproduces the hemodynamic effects of cardiomyoplasty, supporting the heart with a compressing movement, and evaluated its performance in a dedicated mockup system. Nitinol fibers are the device's key component. Ejection fraction (EF), cardiac output (CO), and generated systolic pressure were measured on a test bench. Our test bench settings were a preload range of 0-15 mm Hg, an afterload range of 0-160 mm Hg, and a heart rate (HR) of 20, 30, 40, and 60 beats/min. A power supply of 15 volts and 3.5 amperes was necessary. The EF range went from 34.4% to 1.2% as the afterload and HR increased, along with a CO from 180 to 6 ml/min. The device generated a maximal systolic pressure of 25 mm Hg. Cardiac compression for biventricular assistance in child-sized heart using shape memory alloy is technically feasible. Further testing remains necessary to assess this VAD's in vivo performance range and its reliability.

Bénéfices de l'utilisation d'un test VIH rapide à la permanence PMU-FLON [Benefits of using rapid HIV testing at the PMU-FLON walk-in clinic in Lausanne].

Lab tests are frequently used in primary care to guide patient care. This is particularly the case when a severe disorder, or one that will affect patients' initial care, needs to be excluded rapidly. At the PMU-FLON walk-in clinic the use of HIV testing as recommended by the Swiss Office of Public Health was hampered by the delay in obtaining test results. This led us to introduce rapid HIV testing which provides results within 30 minutes. Following the first 250 tests the authors discuss the results as well as the benefits of rapid HIV testing in an urban walk-in clinic.

Mechanisms regulating the proliferative potential of human CD8+ T lymphocytes overexpressing telomerase.

In human somatic cells, including T lymphocytes, telomeres progressively shorten with each cell division, eventually leading to a state of cellular senescence. Ectopic expression of telomerase results in the extension of their replicative life spans without inducing changes associated with transformation. However, it is yet unknown whether somatic cells that overexpress telomerase are physiologically indistinguishable from normal cells. Using CD8+ T lymphocyte clones overexpressing telomerase, we investigated the molecular mechanisms that regulate T cell proliferation. In this study, we show that early passage T cell clones transduced or not with human telomerase reverse transcriptase displayed identical growth rates upon mitogenic stimulation and no marked global changes in gene expression. Surprisingly, reduced proliferative responses were observed in human telomerase reverse transcriptase-transduced cells with extended life spans. These cells, despite maintaining high expression levels of genes involved in the cell cycle progression, also showed increased expression in several genes found in common with normal aging T lymphocytes. Strikingly, late passage T cells overexpressing telomerase accumulated the cyclin-dependent inhibitors p16Ink4a and p21Cip1 that have largely been associated with in vitro growth arrest. We conclude that alternative growth arrest mechanisms such as those mediated by p16Ink4a and p21Cip1 still remained intact and regulated the growth potential of cells independently of their telomere status.

Discriminant validity and test-retest reliability of a self-administered Internet-based questionnaire testing doctors' knowledge in evidence-based medicine.

Aims and objectives  This study aimed to determine the discriminant validity and the test-retest reliability of a questionnaire testing the impact of evidence-based medicine (EBM) training on doctors' knowledge and skills. Methods  Questionnaires were sent electronically to all doctors working as residents and chief residents in two French speaking hospital networks in Switzerland. Participants completed the questionnaire twice, within a 4-week interval. The discriminant validity was examined in comparing doctors' performance according to their reported EBM previous training. Proportion of agreement between both sessions of the questionnaire, Cohen's kappa and 'uniform kappa' determined its test-retest reliability. Results  The participation rate was 9.8%/7.1% to first/second session. Performance increased according to the level of doctors' previous training in EBM. The observed proportion of agreement between both sessions was over 70% for 14/19 questions, and the 'uniform kappa' was superior to 0.60 for 15/19 questions. Conclusion  The discriminant validity and test-retest reliability of the questionnaire were satisfying. The low participation rate did not prevent the study from achieving its aims.

Internal test sets studies in a group of antimalarials

Topological indices have been applied to build QSAR models for a set of 20 antimalarial cyclic peroxy cetals. In order to evaluate the reliability of the proposed linear models leave-n-out and Internal Test Sets (ITS) approaches have been considered. The proposed procedure resulted in a robust and consensued prediction equation and here it is shown why it is superior to the employed standard cross-validation algorithms involving multilinear regression models

Influència de la dislèxia en els resultats d'eficàcia del test IGF

En el present treball es pretén determinar si existeix una correlació entre la dislèxia (dificultat en l'aprenentatge de la lectura i l'escriptura) i els resultats en el test IGF (intel·ligència general i factorial), concretament els resultats d'eficàcia. Es va seleccionar una mostra d'alumnes a la que, en primer lloc, es va diagnosticar o descartar la dislèxia, i després se'ls-hi va administrar l'IGF. No es van observar diferències significatives en els resultats d'eficàcia del test IGF entre dislèxics i no-dislèxics en dits resultats.

Bystander activation of CD4+ T cells.

Bystander activation of T cells, i.e. the stimulation of unrelated (heterologous) T cells by cytokines during an Ag-specific T-cell response, has been best described for CD8(+) T cells. In the CD8(+) compartment, the release of IFN and IFN-inducers leads to the production of IL-15, which mediates the proliferation of CD8(+) T cells, notably memory-phenotype CD8(+) T cells. CD4(+) T cells also undergo bystander activation, however, the signals inducing this Ag-nonspecific stimulation of CD4(+) T cells are less well known. A study in this issue of the European Journal of Immunology sheds light on this aspect, suggesting that common gamma-chain cytokines including IL-2 might be involved in bystander activation of CD4(+) T cells.

Immunosuppressive effects of streptozotocin-induced diabetes result in absolute lymphopenia and a relative increase of T regulatory cells.

OBJECTIVE Streptozotocin (STZ) is the most widely used diabetogenic agent in animal models of islet transplantation. However, the immunomodifying effects of STZ and the ensuing hyperglycemia on lymphocyte subsets, particularly on T regulatory cells (Tregs), remain poorly understood. RESEARCH DESIGN AND METHODS This study evaluated how STZ-induced diabetes affects adaptive immunity and the consequences thereof on allograft rejection in murine models of islet and skin transplantation. The respective toxicity of STZ and hyperglycemia on lymphocyte subsets was tested in vitro. The effect of hyperglycemia was assessed independently of STZ in vivo by the removal of transplanted syngeneic islets, using an insulin pump, and with rat insulin promoter diphtheria toxin receptor transgenic mice. RESULTS Early lymphopenia in both blood and spleen was demonstrated after STZ administration. Direct toxicity of STZ on lymphocytes, particularly on CD8(+) cells and B cells, was shown in vitro. Hyperglycemia also correlated with blood and spleen lymphopenia in vivo but was not lymphotoxic in vitro. Independently of hyperglycemia, STZ led to a relative increase of Tregs in vivo, with the latter retaining their suppressive capacity in vitro. The higher frequency of Tregs was associated with Treg proliferation in the blood, but not in the spleen, and higher blood levels of transforming growth factor-β. Finally, STZ administration delayed islet and skin allograft rejection compared with naive mice. CONCLUSIONS These data highlight the direct and indirect immunosuppressive effects of STZ and acute hyperglycemia, respectively. Thus, these results have important implications for the future development of tolerance-based protocols and their translation from the laboratory to the clinic.

Cloud code test IDE

L'objectiu principal d'aquest projecte final de carrera consisteix en desenvolupar una aplicació web que oferisca un entorn simplificat de desenvolupament integrat (IDE) en el llenguatge C/C++, on els estudiants de batxillerat (o secundària en general) puguen iniciar-se en el seu estudi. La finalitat és proveir un entorn agradable a l'alumnat perquè puga seguir correctament les pràctiques que proposa el professor independentment de les circumstàncies pròpies d'aquest (ubicació temporal o permanentde l'alumnat, sistema operatiu que utilitza, dispositiu emprat per a fer les pràctiques, etc..).

Differential T cell receptor photoaffinity labeling among H-2Kd restricted cytotoxic T lymphocyte clones specific for a photoreactive peptide derivative. Labeling of the alpha-chain correlates with J alpha segment usage.

Using a direct binding assay based on photoaffinity labeling, we studied the interaction of T cell receptor (TCR) with a Kd-bound photoreactive peptide derivative on living cells. The Kd-restricted Plasmodium berghei circumsporozoite (PbCS) peptide 253-260 (YIPSAEKI) was reacted NH2-terminally with biotin and at the TCR contact residue Lys259 with photoreactive iodo, 4-azido salicylic acid (IASA) to make biotin-YIPSAEK(IASA)I. Cytotoxic T lymphocyte (CTL) clones derived from mice immunized with this derivative recognized this conjugate, but not a related one lacking the IASA group nor the parental PbCS peptide. The clones were Kd restricted. Recognition experiments with variant conjugates, lacking substituents from IASA, revealed a diverse fine specificity pattern and indicated that this group interacted directly with the TCR. The TCR of four clones could be photoaffinity labeled by biotin-YIPSAEK(125IASA)I. This labeling was dependent on the conjugates binding to the Kd molecule and was selective for the TCR alpha (2 clones) or beta chain (1 clone), or was common for both chains (1 clone). TCR sequence analysis showed a preferential usage of J alpha TA28 containing alpha chains that were paired with V beta 1 expressing beta chains. The TCR that were photoaffinity labeled at the alpha chain expressed these J alpha and V beta segments. The tryptophan encoded by the J alpha TA28 segment is rarely found in other J alpha segments. Moreover, we show that the IASA group interacts preferentially with tryptophan in aqueous solution. We thus propose that for these CTL clones, labeling of the alpha chain occurs via the J alpha-encoded tryptophan residue.

Telomere length dynamics in human lymphocyte subpopulations measured by flow cytometry.

To measure the average length of telomere repeats at chromosome ends in individual cells we developed a flow cytometry method using fluorescence in situ hybridization (flow FISH) with labeled peptide nucleic acid (PNA) probes. Results of flow FISH measurements correlated with results of conventional telomere length measurements by Southern blot analysis (R = 0.9). Consistent differences in telomere length in CD8+ T-cell subsets were identified. Naive and memory CD4+ T lymphocytes in normal adults differed by around 2.5 kb in telomere length, in agreement with known replicative shortening of telomeres in lymphocytes in vivo. T-cell clones grown in vitro showed stabilization of telomere length after an initial decline and rare clones capable of growing beyond 100 population doublings showed variable telomere length. These results show that flow FISH can be used to measure specific nucleotide repeat sequences in single cells and indicate that the very large replicative potential of lymphocytes is only indirectly related to telomere length.

Galveston Orientation Amnesia Test (GOAT)

O trauma crânio-encefálico contuso (TCEC) é freqüentemente seguido pela amnésia pós-traumática (APT), caracterizada como um estado transitório de confusão e desorientação. Sua duração tem sido utilizada para quantificar a gravidade do TCEC e prever distúrbios nas funções cognitivas, assim como para antever as alterações na capacidade funcional das vítimas pós-trauma. O Galveston Orientation Amnesia Test (GOAT) é o primeiro instrumento sistematizado criado e o mais amplamente utilizado para avaliar a APT. Este artigo apresenta esse instrumento, as bases conceituais para seu desenvolvimento e a adaptação e validação do GOAT para cultura brasileira. Além disso, descreve sua aplicação e comenta as restrições do seu uso. Resultados de pesquisas realizadas em nosso meio contribuíram para as evidências sobre a validade do GOAT. Também apontaram os indicadores do momento pós-trauma em que o GOAT deve ser aplicado e destacaram as dificuldades no uso desse instrumento.

XMNS, aplicació web per a la correcció automàtica de proves tipus test

Aplicació web per a la correcció automàtica de proves tipus test realitzada amb un framework PHP MVC propi i no comercial.

Practical considerations for conducting ecotoxicity test methods with manufactured nanomaterials: what have we learnt so far?

This review paper reports the consensus of a technical workshop hosted by the European network, NanoImpactNet (NIN). The workshop aimed to review the collective experience of working at the bench with manufactured nanomaterials (MNMs), and to recommend modifications to existing experimental methods and OECD protocols. Current procedures for cleaning glassware are appropriate for most MNMs, although interference with electrodes may occur. Maintaining exposure is more difficult with MNMs compared to conventional chemicals. A metal salt control is recommended for experiments with metallic MNMs that may release free metal ions. Dispersing agents should be avoided, but if they must be used, then natural or synthetic dispersing agents are possible, and dispersion controls essential. Time constraints and technology gaps indicate that full characterisation of test media during ecotoxicity tests is currently not practical. Details of electron microscopy, dark-field microscopy, a range of spectroscopic methods (EDX, XRD, XANES, EXAFS), light scattering techniques (DLS, SLS) and chromatography are discussed. The development of user-friendly software to predict particle behaviour in test media according to DLVO theory is in progress, and simple optical methods are available to estimate the settling behaviour of suspensions during experiments. However, for soil matrices such simple approaches may not be applicable. Alternatively, a Critical Body Residue approach may be taken in which body concentrations in organisms are related to effects, and toxicity thresholds derived. For microbial assays, the cell wall is a formidable barrier to MNMs and end points that rely on the test substance penetrating the cell may be insensitive. Instead assays based on the cell envelope should be developed for MNMs. In algal growth tests, the abiotic factors that promote particle aggregation in the media (e.g. ionic strength) are also important in providing nutrients, and manipulation of the media to control the dispersion may also inhibit growth. Controls to quantify shading effects, and precise details of lighting regimes, shaking or mixing should be reported in algal tests. Photosynthesis may be more sensitive than traditional growth end points for algae and plants. Tests with invertebrates should consider non-chemical toxicity from particle adherence to the organisms. The use of semi-static exposure methods with fish can reduce the logistical issues of waste water disposal and facilitate aspects of animal husbandry relevant to MMNs. There are concerns that the existing bioaccumulation tests are conceptually flawed for MNMs and that new test(s) are required. In vitro testing strategies, as exemplified by genotoxicity assays, can be modified for MNMs, but the risk of false negatives in some assays is highlighted. In conclusion, most protocols will require some modifications and recommendations are made to aid the researcher at the bench. [Authors]

Novel Agents Targeting the IGF-1R/PI3K Pathway Impair Cell Proliferation and Survival in Subsets of Medulloblastoma and Neuroblastoma.

The receptor tyrosine kinase (RTK)/phosphoinositide 3-kinase (PI3K) pathway is fundamental for cancer cell proliferation and is known to be frequently altered and activated in neoplasia, including embryonal tumors. Based on the high frequency of alterations, targeting components of the PI3K signaling pathway is considered to be a promising therapeutic approach for cancer treatment. Here, we have investigated the potential of targeting the axis of the insulin-like growth factor-1 receptor (IGF-1R) and PI3K signaling in two common cancers of childhood: neuroblastoma, the most common extracranial tumor in children and medulloblastoma, the most frequent malignant childhood brain tumor. By treating neuroblastoma and medulloblastoma cells with R1507, a specific humanized monoclonal antibody against the IGF-1R, we could observe cell line-specific responses and in some cases a strong decrease in cell proliferation. In contrast, targeting the PI3K p110α with the specific inhibitor PIK75 resulted in broad anti-proliferative effects in a panel of neuro- and medulloblastoma cell lines. Additionally, sensitization to commonly used chemotherapeutic agents occurred in neuroblastoma cells upon treatment with R1507 or PIK75. Furthermore, by studying the expression and phosphorylation state of IGF-1R/PI3K downstream signaling targets we found down-regulated signaling pathway activation. In addition, apoptosis occurred in embryonal tumor cells after treatment with PIK75 or R1507. Together, our studies demonstrate the potential of targeting the IGF-1R/PI3K signaling axis in embryonal tumors. Hopefully, this knowledge will contribute to the development of urgently required new targeted therapies for embryonal tumors.