The use of wheat-germ lectin-Sepharose for the purification of human haemopexin.

Haemopexin was prepared in 37% yield from normal human serum by a simple procedure involving fractional poly(ethylene glycol) precipitation and subsequent chromatography on DEAE-Sepharose CL-6B. One peak from the ion exchanger consisted of only haemopexin and transferrin. These proteins were separated by chromatography on wheat-germ lectin-Sepharose 6MB. Haemopexin was selectively bound and was subsequently desorbed by N-acetyl-D-glucosamine. No impurities could be detected in the final preparation by immunoelectrophoresis or by immunodiffusion against a range of antisera. The protein gave two partially separated bands in polyacrylamide-gradient-gel electrophoresis, corresponding to apohaemopexin and haem-haemopexin complex.     

Comparison of normalisation methods for surface-enhanced laser desorption and ionisation (SELDI) time-of-flight (TOF) mass spectrometry data

Background  

Mass spectrometry for biological data analysis is an active field of research, providing an efficient way of high-throughput proteome screening. A popular variant of mass spectrometry is SELDI, which is often used to measure sample populations with the goal of developing (clinical) classifiers. Unfortunately, not only is the data resulting from such measurements quite noisy, variance between replicate measurements of the same sample can be high as well. Normalisation of spectra can greatly reduce the effect of this technical variance and further improve the quality and interpretability of the data. However, it is unclear which normalisation method yields the most informative result.     

A harpacticoid copepod Microsetella spp. from sub-Arctic coastal waters and its sensitivity towards the polyaromatic hydrocarbon pyrene

Species of the harpacticoid copepod genus Microsetella are commonly reported to occur in Arctic and sub-Arctic coastal waters, but nothing has yet been reported on their sensitivity towards toxic substances. Effects of the polyaromatic hydrocarbon pyrene on Microsetella spp. from Western Greenland were investigated by looking at survival of females, feeding status, and nucleic acid content after a 96-h exposure. Less than 10% survived at 100 nM exposure concentration, and a 50% reduced survival was also evident at 0.1 and 10 nM. The RNA:DNA ratio was significantly higher, 2.1 ng/individual, at the lowest concentration of 0.01 nM compared to 0.9 ng/individual in the control, which indicates increased metabolic activities. A reduced DNA content in higher exposure concentrations of 1–100 nM suggests inhibition of egg development. Gut content was significantly declining with increasing exposure concentrations with only 2% of exposed females displaying full guts at 100 nM pyrene. Together with reduced feeding activity, effects at the population level can be anticipated, but would have to be confirmed in future experiments. The data suggests a higher sensitivity of Microsetella spp. compared to other Arctic copepods, which implies more severe effects from oil on the pelagic food web in the areas and periods where Microsetella spp. dominates Arctic plankton food webs.     

20-year trajectories of positive and negative symptoms after the first psychotic episode in patients with schizophrenia spectrum disorder: results from the OPUS study

This study aimed to identify the 20-year trajectories of positive and negative symptoms after the first psychotic episode in a sample of patients with an ICD-10 diagnosis of schizophrenia spectrum disorder, and to investigate the baseline characteristics and long-term outcomes associated with these trajectories. A total of 373 participants in the OPUS trial were included in the study. Symptoms were assessed at baseline and after 1, 2, 5, 10 and 20 years using the Scales for the Assessment of Positive and Negative Symptoms. We used latent class growth mixture modelling to identify trajectories, and multinominal regression analyses to investigate predictors of membership to identified trajectories. Five trajectories of positive symptoms were identified: early continuous remission (50.9% of the sample), stable improvement (18.0%), intermittent symptoms (10.2%), relapse with moderate symptoms (11.9%), and continuous severe symptoms (9.1%). Substance use disorder (odds ratio, OR: 2.83, 95% CI: 1.09-7.38, p=0.033), longer duration of untreated psychosis (OR: 1.02, 95% CI: 1.00-1.03, p=0.007) and higher level of negative symptoms (OR: 1.60, 95% CI: 1.07-2.39, p=0.021) were predictors of the relapse with moderate symptoms trajectory, while only longer duration of untreated psychosis (OR: 1.01, 95% CI: 1.00-1.02, p=0.030) predicted membership to the continuous severe symptoms trajectory. Two trajectories of negative symptoms were identified: symptom remission (51.0%) and continuous symptoms (49.0%). Predictors of the continuous symptoms trajectory were male sex (OR: 3.03, 95% CI: 1.48-6.02, p=0.002) and longer duration of untreated psychosis (OR: 1.01, 95% CI: 1.00-1.02, p=0.034). Trajectories displaying continuous positive and negative symptoms were linked to lower neurocognition, as measured by the Brief Assessment of Cognition in Schizophrenia (BACS) (z-score: –0.78, CI: –1.39 to –0.17, for continuous positive symptoms; z-score: –0.33, CI: –0.53 to –0.13, for continuous negative symptoms). The same trajectories were also linked to higher use of antipsychotic medication at 20-year follow-up (continuous positive symptoms: 78%; continuous negative symptoms: 67%). These findings suggest that the majority of patients with first-episode schizophrenia spectrum disorder have a trajectory with early stable remission of positive symptoms. Long duration of untreated psychosis and comorbid substance abuse are modifiable predictors of poor trajectories for positive symptoms in these patients. In about half of patients, negative symptoms do not improve over time. These symptoms, in addition to being associated with poor social and neurocognitive functioning, may prevent patients from seeking help.     

Maresin 1 attenuates pro-inflammatory activation induced by β-amyloid and stimulates its uptake

Alzheimer's disease (AD) is the most common dementia, characterized by pathological accumulation of β-amyloid (Aβ) and hyperphosphorylation of tau protein, together with a damaging chronic inflammation. The lack of effective treatments urgently warrants new therapeutic strategies. Resolution of inflammation, associated with beneficial and regenerative activities, is mediated by specialized pro-resolving lipid mediators (SPMs) including maresin 1 (MaR1). Decreased levels of MaR1 have been observed in AD brains. However, the pro-resolving role of MaR1 in AD has not been fully investigated. In the present study, human monocyte-derived microglia (MdM) and a differentiated human monocyte cell line (THP-1 cells) exposed to Aβ were used as models of AD neuroinflammation. We have studied the potential of MaR1 to inhibit pro-inflammatory activation of Aβ and assessed its ability to stimulate phagocytosis of Aβ₄₂. MaR1 inhibited the Aβ₄₂-induced increase in cytokine secretion and stimulated the uptake of Aβ₄₂ in both MdM and differentiated THP-1 cells. MaR1 was also found to decrease chemokine secretion and reduce the associated increase in the activation marker CD40. Activation of kinases involved in transduction of inflammation was not affected by MaR1, but the activity of nuclear factor (NF)-κB was decreased. Our data show that MaR1 exerts effects that indicate a pro-resolving role in the context of AD and thus presents itself as a potential therapeutic target for AD.     

HAT: Hypergeometric Analysis of Tiling-arrays with application to promoter-GeneChip data

Background  

Tiling-arrays are applicable to multiple types of biological research questions. Due to its advantages (high sensitivity, resolution, unbiased), the technology is often employed in genome-wide investigations. A major challenge in the analysis of tiling-array data is to define regions-of-interest, i.e., contiguous probes with increased signal intensity (as a result of hybridization of labeled DNA) in a region. Currently, no standard criteria are available to define these regions-of-interest as there is no single probe intensity cut-off level, different regions-of-interest can contain various numbers of probes, and can vary in genomic width. Furthermore, the chromosomal distance between neighboring probes can vary across the genome among different arrays.     

Genetic Variation in Amount of Salivary Amylase in the Bank Vole, CLETHRIONOMYS GLAREOLA

Several investigated bank vole populations are polymorphis for the number of salivary amylase loci, and individual chromosomes may carry one, two or three linked amylase structural genes. In the present study, we have used bank vole stocks homozygous for different chromosomes to investigate the relationship between amylase production and gene number. By measuring the amylase activity in parotid glands and the percentage of amylase protein in saliva, we have been able to demonstrate that the amount of salivary amylase is directly proportional to the proposed gene number. The paper also describes the allele, AmySu, which codes for a heat-labile salivary amylase. The relative amounts of the heat-labile isozyme have been determined in different heterozygotes containing this allele, and these results also support the multiple locus model. Finally, a stock devoid of salivary amylase activity was established. Animals from this strain have, however, a protein in the parotid glands and in saliva that is very similar to amylase in molecular weight, amino acid composition and in its binding to glycogen and cyclohepta-amylose. In genetic crosses, the protein segregates as an amylase allele. Therefore, this protein, encoded by the functionally null allele AmyN, may represent an incorrectly processed amylase precursor.