Visible diode lasers can be used for flow cytometric immunofluorescence and DNA analysis

This report describes a feasibility study concerning the use of a visible diode laser for two important fluorescence applications in a flow cytometer. With a 3 mW 635 nm. diode laser, we performed immunofluorescence measurements using the fluorophore allophycocyanin (APC). We have measured CD8 positive lymphocytes with a two-step labeling procedure and the resulting histograms showed good separation between the negative cells and the dim and the bright fluorescent subpopulations. As a second fluorescence application, we chose DNA analysis with the recently developed DNA/ RNA stains TOTO-3 and TO-PRO-3. In our setup TO-PRO-3 yielded the best results with a CV of 3.4%. Our results indicate that a few milliwatts of 635 nm light from a visible diode laser is sufficient to do single color immunofluorescence measurements with allophycocyanin and DNA analysis with TO-PRO-3. The major advantages of using a diode laser in a flow cytometer are the small size, the low price, the high efficiency, and the long lifetime

Healthcare expenditure prediction with neighbourhood variables:A random forest model

We investigated the additional predictive value of an individual’s neighbourhood (quality and location), and of changes therein on his/her healthcare costs. To this end, we combined several Dutch nationwide data sources from 2003 to 2014, and selected inhabitants who moved in 2010. We used random forest models to predict the area under the curve of the regular healthcare costs of individuals in the years 2011–2014. In our analyses, the quality of the neighbourhood before the move appeared to be quite important in predicting healthcare costs (i.e. importance rank 11 out of 126 socio-demographic and neighbourhood variables; rank 73 out of 261 in the full model with prior expenditure and medication). The predictive performance of the models was evaluated in terms of R2 (or proportion of explained variance) and MAE (mean absolute (prediction) error). The model containing only socio-demographic information improved marginally when neighbourhood was added (R2 +0.8%, MAE −€5). The full model remained the same for the study population (R2 = 48.8%, MAE of €1556) and for subpopulations. These results indicate that only in prediction models in which prior expenditure and utilization cannot or ought not to be used neighbourhood might be an interesting source of information to improve predictive performance

Autofocus and two-fold astigmatism correction in HAADF-STEM

A new simultaneous autofocus and two-fold astigmatism correction method is proposed for High Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF-STEM). The method makes use of a modification of an image variance, which has already been used before as an image quality measure for different types of microscopy. In this paper we describe numerical simulations based on a classical HAADF-STEM linear image formation model showing that the modified variance reaches it's maximum for Scherzer focus and zero astigmatism. In order to find this maximum in a three-parameter space we employ the well-known Nelder-Mead simplex optimization algorithm. The method is implemented and tested on a FEI Tecnai F20.It successfully finds the optimal defocus and zero astigmatism with the time and accuracy, compared with the human operator. The method is iterative, and finding the optimal defocus and zero astigmatism requires obtaining typically 20-50 images

Increased prevalence of metabolic syndrome in patients with bipolar disorder compared to a selected control group-a Northern Netherlands LifeLines population cohort study

OBJECTIVES: Metabolic syndrome (MetS) is highly prevalent among patients with bipolar disorder (BD). The aims of this cross-sectional study were to determine the prevalence of MetS in Dutch BD subjects and compare it with a control group, to examine the association of demographic and clinical characteristics with MetS in BD, and to determine the extent to which metabolic dysregulation is treated in those patients. METHODS: 493 Dutch adult patients (≥ 18 years) with BD receiving psychotropic drugs and 493 matched control subjects were compared using data from the biobank Lifelines. We determined MetS according to the National Cholesterol Education Program Adult Treatment Panel III-Adapted (NCEP ATP III-A) criteria. The difference in the prevalence of MetS and the associations with characteristics were analyzed with logistic regression. RESULTS: BD subjects (30.6%) showed a significantly higher prevalence of MetS compared to the control group (14.2%) (p < .001, OR:2.67, 95% CI:1.94-3.66). Univariate analysis showed that smoking, body mass index (BMI) and antidepressant drug use were associated with MetS. Multivariate analysis showed that smoking (OR:2.01) was independently associated with MetS in BD. For hypertension, hyperglycemia and lipid disorder pharmacological treatment was provided to respectively 69.5%, 24% and 18.4% of the BD subjects in our sample. LIMITATIONS: Duration of illness of BD subjects was unknown. CONCLUSIONS: This study demonstrated a higher prevalence of MetS in Dutch BD subjects compared to persons without BD. In addition, a remarkable undertreatment of some of the components of MetS was found

Poliovirus-specific memory immunity in seronegative elderly people does not protect against virus excretion.

BACKGROUND: Dutch people born between 1925 and 1945 were ineligible for vaccination with the inactivated poliovirus vaccine (IPV) introduced in 1957 and may have escaped natural infection because of reduced poliovirus circulation. We examined whether people with low or undetectable antibody levels are susceptible to infection and whether memory immunity provides protection against virus excretion. METHODS: A total of 429 elderly participants were challenged with monovalent oral poliovirus vaccine (type 1 or 3) and followed for 8 weeks. Immune responses and virus excretion were compared for 4 groups, defined on the basis of seronegativity for poliovirus type 1 or 3, natural immunity, and IPV-induced immunity. RESULTS: On the basis of the rapidity of the antibody response and the absence of immunoglobulin M, we saw clear evidence of memory immune responses in 33% of the participants without detectable antibodies against poliovirus type 1 and in 5% of the participants without detectable antibodies against poliovirus type 3. Fecal virus-excretion patterns were not significantly different for seronegative participants, regardless of whether they showed evidence of memory immunity. CONCLUSIONS: Rapid antibody responses after challenge with oral polio vaccine provide evidence for poliovirus-specific memory immunity in seronegative elderly people. However, in contrast to preexisting immunity, memory immunity does not protect against virus excretion. These results have important implications for the poliomyelitis-eradication initiative, in particular for future immunization policies after eradication has been achieved

Effects of selective breeding for increased wheel-running behavior on circadian timing of substrate oxidation and ingestive behavior

Fluctuations in substrate preference and utilization across the circadian cycle may be influenced by the degree of physical activity and nutritional status. In the present study, we assessed these relationships in control mice and in mice from a line selectively bred for high voluntary wheel-running behavior, either when feeding a carbohydrate-rich/low-fat (LF) or a high-fat (HF) diet. Housed without wheels, selected mice, and in particular the females, exhibited higher cage activity than their non-selected controls during the dark phase and at the onset of the light phase, irrespective of diet. This was associated with increases in energy expenditure in both sexes of the selection line. In selected males, carbohydrate oxidation appeared to be increased compared to controls. In contrast, selected females had profound increases in fat oxidation above the levels in control females to cover the increased energy expenditure during the dark phase. This is remarkable in light of the finding that the selected mice, and in particular the females showed higher preference for the LF diet relative to controls. It is likely that hormonal and/or metabolic signals increase carbohydrate preference in the selected females, which may serve optimal maintenance of cellular metabolism in the presence of augmented fat oxidation. (C) 2010 Elsevier Inc. All rights reserved

Interferon score is increased in incomplete systemic lupus erythematosus and correlates with myxovirus-resistance protein A in blood and skin

OBJECTIVES: Patients with incomplete systemic lupus erythematosus (iSLE) have lupus features, but do not meet classification criteria for SLE. Type I interferons (IFN) are important early mediators in SLE, and IFN upregulation in incomplete SLE may be associated with progression to SLE. Since many patients present with skin symptoms, the aim of this study is to investigate IFN type I expression and IFN-related mediators in the blood and skin of iSLE patients.METHODS: Twenty-nine iSLE patients (ANA titer ≥ 1:80, symptoms &lt; 5 years, ≥ 1 objectified clinical criterion), 39 SLE patients with quiescent disease (fulfilling ACR or SLICC criteria, SLEDAI ≤4), and 22 healthy controls were included. IFN signature was measured in whole blood, based on 12 IFN-related genes, using RT-PCR, and IFN-score was calculated. IFN-related mediators myxovirus-resistance protein A (MxA), IFN-γ-induced protein 10 (IP-10), and monocyte chemoattractant protein (MCP-1) were measured using ELISA. IFN type I expression in the unaffected skin was analyzed by immunostaining with MxA.RESULTS: IFN-score was increased in 50% of iSLE patients and 46% of SLE patients and correlated positively with the number of autoantibodies, anti-SSA titer, ESR, and IgG and negatively with C4 in iSLE. Levels of MxA correlated strongly with IFN-score (r = 0.78, p &lt; 0.0001). Furthermore, MxA expression was found in 29% of unaffected skin biopsies of iSLE and 31% of SLE patients and also correlated with IFN-score (r = 0.54, p &lt; 0.0001).CONCLUSIONS: IFN-score was increased in half of the iSLE patients, and given the correlation with complement and autoantibody diversity, this suggests a higher risk for disease progression. MxA in the blood and unaffected skin correlated strongly with the IFN-score and is possibly an easily applicable marker for IFN upregulation.</p