Disrupted segregation of working memory networks in temporal lobe epilepsy

Working memory is a critical building block for almost all cognitive tasks, and impairment can cause significant disruption to daily life routines. We investigated the functional connectivity (FC) of the visuo-spatial working memory network in temporal lobe epilepsy and its relationship to the underlying white matter tracts emanating from the hippocampus. Fifty-two patients with unilateral hippocampal sclerosis (HS) (30 left) and 30 healthy controls underwent working memory functional MRI (fMRI) and Diffusion Tensor Imaging (DTI). Six seed regions were identified for FC analysis; 4 within a task-positive network (left and right middle frontal gyri and superior parietal lobes), and 2 within a task-negative network (left and right hippocampi). FC maps were created by extracting the time-series of the fMRI signal in each region in each subject and were used as regressors of interest for additional GLM fMRI analyses. Structural connectivity (SC) corresponding to areas to which the left and right hippocampi were connected was determined using tractography, and a mean FA for each hippocampal SC map was calculated. Both left and right HS groups showed atypical FC between task-positive and task-negative networks compared to controls. This was characterised by co-activation of the task-positive superior parietal lobe ipsilateral to the typically task-negative sclerosed hippocampus. Correlational analysis revealed stronger FC between superior parietal lobe and ipsilateral hippocampus, was associated with worse performance in each patient group. The SC of the hippocampus was associated with the intra-hemispheric FC of the superior parietal lobe, in that greater SC was associated with weaker parieto-frontal FC. The findings suggest that the segregation of the task-positive and task-negative FC networks supporting working memory in TLE is disrupted, and is associated with abnormal structural connectivity of the sclerosed hippocampus. Co-activation of parieto-temporal regions was associated with poorer working memory and this may be associated with working memory dysfunction in TLE

Utility of CD4 cell counts for early prediction of virological failure during antiretroviral therapy in a resource-limited setting

BACKGROUND: Viral load monitoring is not available for the vast majority of patients receiving antiretroviral therapy in resource-limited settings. However, the practical utility of CD4 cell count measurements as an alternative monitoring strategy has not been rigorously assessed. METHODS: In this study, we used a novel modelling approach that accounted for all CD4 cell count and VL values measured during follow-up from the first date that VL suppression was achieved. We determined the associations between CD4 counts (absolute values and changes during ART), VL measurements and risk of virological failure (VL > 1,000 copies/ml) following initial VL suppression in 330 patients in South Africa. CD4 count changes were modelled both as the difference from baseline (DeltaCD4 count) and the difference between consecutive values (CD4 count slope) using all 3-monthly CD4 count measurements during follow-up. RESULTS: During 7093.2 patient-months of observation 3756 paired CD4 count and VL measurements were made. In patients who developed virological failure (n = 179), VL correlated significantly with absolute CD4 counts (r = - 0.08, P = 0.003), DeltaCD4 counts (r = - 0.11, P < 0.01), and most strongly with CD4 count slopes (r = - 0.30, P < 0.001). However, the distributions of the absolute CD4 counts, DeltaCD4 counts and CD4 count slopes at the time of virological failure did not differ significantly from the corresponding distributions in those without virological failure (P = 0.99, P = 0.92 and P = 0.75, respectively). Moreover, in a receiver operating characteristic (ROC) curve, the association between a negative CD4 count slope and virological failure was poor (area under the curve = 0.59; sensitivity = 53.0%; specificity = 63.6%; positive predictive value = 10.9%). CONCLUSION: CD4 count changes correlated significantly with VL at group level but had very limited utility in identifying virological failure in individual patients. CD4 count is an inadequate alternative to VL measurement for early detection of virological failure

Ethnic minorities and prescription medication; concordance between self-reports and medical records

BACKGROUND: Ethnic differences in health care utilisation are frequently reported in research. Little is known about the concordance between different methods of data collection among ethnic minorities. The aim of this study was to examine to which extent ethnic differences between self-reported data and data based on electronic medical records (EMR) from general practitioners (GPs) might be a validity issue or reflect a lower compliance among minority groups. METHODS: A cross-sectional, national representative general practice study, using EMR data from 195 GPs. The study population consisted of Dutch, Turks, Surinamese, Antilleans and Morrocans. Self-reported data were collected through face-to-face interviews and could be linked to the EMR of GPs. The main outcome measures were the level of agreement between annual prescribing rate based on the EMRs of GPs and the self-reported receipt and use of prescriptions during the preceding 14 days. RESULTS: The pattern of ethnic differences in receipt and use of prescription medication depended on whether self-reported data or EMR data were used. Ethnic differences based on self-reports were not consistently reflected in EMR data. The percentage of agreement above chance between EMR data and self-reported receipt was in general relative low. CONCLUSION: Ethnic differences between self-reported data and EMR data might not be fully perceived as a cross-cultural validity issue. At least for Moroccans and Turks, compliance with the prescribed medication by the GP is suggested not to be optimal

LYL1 Degradation by the Proteasome Is Directed by a N-Terminal PEST Rich Site in a Phosphorylation-Independent Manner

Background: The Lymphoblastic leukemia 1 (LYL1) gene is a proto-oncogenic transcription factor found upregulated in patients with T-cell acute lymphoblastic leukemia (T-cell ALL). Initially, the upregulation was described to be as a result of a translocation. However, further studies revealed that transcriptional upregulation of LYL1could also occur without translocations. In addition, post-translational mechanisms, such as protein degradation could influence LYL1 expression as well. Methodology/Principal Findings: In this study, we considered possible post-translational regulation of Lyl1, and investigated fundamental mechanisms governing LYL1 degradation in cell-based culture assays. We identify a PEST sequence motif located in the N-terminus of LYL1, which determines the efficiency of LYL1 degradation by the proteasome. The absence of the PEST degradation site leads to accumulation or upregulation of LYL1. We also show that LYL1 is phosphorylated by MAPK at S36, and determined that proteasomal degradation of LYL1 occurs in a phosphorylationindependent manner. Conclusions/Significance: Understanding LYL1 degradation is a step forward not only towards deciphering the normal function and regulation of LYL1, but could suggest post-translational mechanisms for upregulation of LYL1 that ma

p27 Deficiency Cooperates with Bcl-2 but Not Bax to Promote T-Cell Lymphoma

The effect of Bcl-2 on oncogenesis is complex and expression may either delay or accelerate oncogenesis. The pro-oncogenic activity is attributed to its well characterized anti-apoptotic function while the anti-oncogenic function has been attributed to its inhibition of cellular proliferation. Recent studies demonstrate that p27 may mediate the effects of Bcl-2 on cellular proliferation. We hypothesized that p27 may suppress tumor formation by Bcl-2 family members. To test this hypothesis, cell cycle inhibition and lymphoma development were examined in Lck-Bcl-2 and Lck-Bax38/1 transgenic mice deficient in p27. Strikingly, p27 deficiency synergistically cooperates with Bcl-2 to increase T cell hyperplasia and development of spontaneous T cell lymphomas. Within 1 year, >90% of these mice had developed thymic T cell lymphomas. This high penetrance contrasts with a one year incidence of <5% of thymic lymphoma in Lck-Bcl-2 or p27 −/− mice alone. In contrast, p27 deficiency had no effect on tumor formation in Lck-Bax38/1 transgenic mice, another model of T cell lymphoma. Histologically the lymphomas in p27 −/− Lck-Bcl-2 mice are lymphoblastic and frequently involve multiple organs suggesting an aggressive phenotype. Interestingly, in mature splenic T cells, Bcl-2 largely retains its anti-proliferative function even in the absence of p27. T cells from p27 −/− Lck-Bcl-2 mice show delayed kinetics of CDK2 Thr-160 phosphorylation. This delay is associated with a delay in the up regulation of both Cyclin D2 and D3. These data demonstrate a complex relationship between the Bcl-2 family, cellular proliferation, and oncogenesis and demonstrate that p27 up-regulation is not singularly important in the proliferative delay observed in T cells expressing Bcl-2 family members. Nonetheless, the results indicate that p27 is a critical tumor suppressor in the context of Bcl-2 expression

Dietary fat increases solid tumor growth and metastasis of 4T1 murine mammary carcinoma cells and mortality in obesity-resistant BALB/c mice

Introduction High-fat diets (HFDs) are known to cause obesity and are associated with breast cancer progression and metastasis. Because obesity is associated with breast cancer progression, it is important to determine whether dietary fat per se stimulates breast cancer progression in the absence of obesity. This study investigated whether an HFD increases breast cancer growth and metastasis, as well as mortality, in obesity-resistant BALB/c mice. Methods The 4-week-old, female BALB/c mice were fed HFD (60% kcal fat) or control diet (CD, 10% kcal fat) for 16 weeks. Subsequently, 4T1 mammary carcinoma cells were injected into the inguinal mammary fat pads of mice fed continuously on their respective diets. Cell-cycle progression, angiogenesis, and immune cells in tumor tissues, proteases and adhesion molecules in the lungs, and serum cytokine levels were analyzed with immunohistochemistry, Western blotting, and enzyme-linked immunosorbent assay (ELISA). In vitro studies were also conducted to evaluate the effects of cytokines on 4T1 cell viability, migration, and adhesion. Results Spleen and gonadal fat-pad weights, tumor weight, the number and volume of tumor nodules in the lung and liver, and tumor-associated mortality were increased in the HFD group, with only slight increases in energy intake and body weight. HF feeding increased macrophage infiltration into adipose tissues, the number of lipid vacuoles and the expression of cyclin-dependent kinase (CDK)2, cyclin D1, cyclin A, Ki67, CD31, CD45, and CD68 in the tumor tissues, and elevated serum levels of complement fragment 5a (C5a), interleukin (IL)-16, macrophage colony-stimulating factor (M-CSF), soluble intercellular adhesion molecule (sICAM)-1, tissue inhibitors of metalloproteinase (TIMP)-1, leptin, and triggering receptor expressed on myeloid cells (TREM)-1. Protein levels of the urokinase-type plasminogen activator, ICAM-1, and vascular cell adhesion molecule-1 were increased, but plasminogen activator inhibitor-1 levels were decreased in the lungs of the HFD group. In vitro assays using 4T1 cells showed that sICAM-1 increased viability; TREM-1, TIMP-1, M-CSF, and sICAM-1 increased migration; and C5a, sICAM-1, IL-16, M-CSF, TIMP-1, and TREM-1 increased adhesion. Conclusions Dietary fat increases mammary tumor growth and metastasis, thereby increasing mortality in obesity-resistant mice

Lipids revert inert Aβ amyloid fibrils to neurotoxic protofibrils that affect learning in mice

Although soluble oligomeric and protofibrillar assemblies of Aβ-amyloid peptide cause synaptotoxicity and potentially contribute to Alzheimer's disease (AD), the role of mature Aβ-fibrils in the amyloid plaques remains controversial. A widely held view in the field suggests that the fibrillization reaction proceeds ‘forward' in a near-irreversible manner from the monomeric Aβ peptide through toxic protofibrillar intermediates, which subsequently mature into biologically inert amyloid fibrils that are found in plaques. Here, we show that natural lipids destabilize and rapidly resolubilize mature Aβ amyloid fibers. Interestingly, the equilibrium is not reversed toward monomeric Aβ but rather toward soluble amyloid protofibrils. We characterized these ‘backward' Aβ protofibrils generated from mature Aβ fibers and compared them with previously identified ‘forward' Aβ protofibrils obtained from the aggregation of fresh Aβ monomers. We find that backward protofibrils are biochemically and biophysically very similar to forward protofibrils: they consist of a wide range of molecular masses, are toxic to primary neurons and cause memory impairment and tau phosphorylation in mouse. In addition, they diffuse rapidly through the brain into areas relevant to AD. Our findings imply that amyloid plaques are potentially major sources of soluble toxic Aβ-aggregates that could readily be activated by exposure to biological lipids

E2F5 status significantly improves malignancy diagnosis of epithelial ovarian cancer

<p>Abstract</p> <p>Background</p> <p>Ovarian epithelial cancer (OEC) usually presents in the later stages of the disease. Factors, especially those associated with cell-cycle genes, affecting the genesis and tumour progression for ovarian cancer are largely unknown. We hypothesized that over-expressed transcription factors (TFs), as well as those that are driving the expression of the OEC over-expressed genes, could be the key for OEC genesis and potentially useful tissue and serum markers for malignancy associated with OEC.</p> <p>Methods</p> <p>Using a combination of computational (selection of candidate TF markers and malignancy prediction) and experimental approaches (tissue microarray and western blotting on patient samples) we identified and evaluated E2F5 transcription factor involved in cell proliferation, as a promising candidate regulatory target in early stage disease. Our hypothesis was supported by our tissue array experiments that showed E2F5 expression only in OEC samples but not in normal and benign tissues, and by significantly positively biased expression in serum samples done using western blotting studies.</p> <p>Results</p> <p>Analysis of clinical cases shows that of the E2F5 status is characteristic for a different population group than one covered by CA125, a conventional OEC biomarker. E2F5 used in different combinations with CA125 for distinguishing malignant cyst from benign cyst shows that the presence of CA125 or E2F5 increases sensitivity of OEC detection to 97.9% (an increase from 87.5% if only CA125 is used) and, more importantly, the presence of both CA125 and E2F5 increases specificity of OEC to 72.5% (an increase from 55% if only CA125 is used). This significantly improved accuracy suggests possibility of an improved diagnostics of OEC. Furthermore, detection of malignancy status in 86 cases (38 benign, 48 early and late OEC) shows that the use of E2F5 status in combination with other clinical characteristics allows for an improved detection of malignant cases with sensitivity, specificity, F-measure and accuracy of 97.92%, 97.37%, 97.92% and 97.67%, respectively.</p> <p>Conclusions</p> <p>Overall, our findings, in addition to opening a realistic possibility for improved OEC diagnosis, provide an indirect evidence that a cell-cycle regulatory protein E2F5 might play a significant role in OEC pathogenesis.</p

Evolution of BCL-2/IgH hybrid gene RNA expression during treatment of T(14;18)-bearing follicular lymphomas

Bcl-2, the gene over-expressed in follicular lymphomas (FL), is able to block chemotherapy-induced apoptosis. Consequently, we wondered whether bcl-2/IgH expression variations during treatment of FL could predict the outcome of patients with t(14;18)-bearing FL. For this purpose, we used a reverse transcription polymerase chain reaction (RT-PCR) assay to analyse 180 serial peripheral blood samples (PBS) during 34 treatment phases in 25 patients with t(14;18)-bearing FL. In all patients but two, bcl-2/IgH gene expression was demonstrated in pre-treatment samples. During 16 out of the 34 treatment phases (47%), bcl-2/IgH expression became negative: all but one were responders to chemotherapy. This conversion was transient in six cases. In 18 treatment phases, bcl2/IgH expression remained detectable: eight were clinically considered as treatment failures, while eight others achieved PR and two achieved CR. We observed a significant correlation between treatment response and RNA PCR results (P = 0.002). Three-year overall survival of patients with stable bcl2/IgH-negative conversion was 100% compared to 54% for the remaining patients (P = 0.069); 3-year freedom from progression was respectively 87.5% and 13% (P = 0.005). These results indicate a correlation between bcl-2/IgH expression variations and both clinical response and outcome. Whether this might predict disease outcome early remains to be confirmed. © 1999 Cancer Research Campaig