Amino acid sequence and distribution of mRNA encoding a major skeletal muscle laminin binding protein: an extracellular matrix-associated protein with an unusual COOH-terminal polyaspartate domain.

Two cDNAs encoding an abundant chicken muscle extracellular matrix (ECM)-associated laminin-binding protein (LBP) have been isolated and sequenced. The predicted primary amino acid sequence includes a probable signal peptide and a site for N-linked glycosylation, but lacks a hydrophobic segment long enough to span the membrane. The COOH terminus consists of an unusual repeat of 33 consecutive aspartate residues. Comparison with other sequences indicates that this protein is different from previously described LBPs and ECM receptors. RNA blot analysis of LBP gene expression showed that LBP mRNA was abundant in skeletal and heart muscle, but barely detectable in other tissues. Blots of chicken genomic DNA suggest that a single gene encodes this LBP. The amino acid sequence and mRNA distribution are consistent with the biochemical characterization described by Hall and co-workers (Hall, D. E., K. A. Frazer, B. C. Hahn, and L. F. Reichardt. 1988. J. Cell Biol. 107:687-697). These analyses indicate that LBP is an abundant ECM-associated muscle protein with an unusually high negative charge that interacts with both membranes and laminin, and has properties of a peripheral, not integral membrane protein. Taken together, our studies show that muscle LBP is a secreted, peripheral membrane protein with an unusual polyaspartate domain. Its laminin and membrane binding properties suggest that it may help mediate muscle cell interactions with the extracellular matrix. We propose the name "aspartactin" for this LBP

Comparison of four commercial immunomagnetic separation kits for the detection of Cryptosporidium

Cryptosporidium spp. are protozoan parasites of significant health importance found in environmental waters globally. Four commercially available Cryptosporidium-specific immunomagnetic separation (IMS) kits used in various water sample matrices were analysed and compared. Beads were characterised by flow cytometry and tested for the recovery efficiencies for oocysts spiked into different matrices: river water sediment, clay sample, and filter backwash sample. Results showed that DynabeadsTM Cryptosporidium and Waterborne Crypto-GrabTM kits contained immunoglobulin IgM antibody-coated beads. In contrast, the BioPoint CryptoBead and the TCS Isolate kits contained immunoglobulin IgG antibody-coated beads. BioPoint CryptoBead was significantly coated with more antibodies and were able to capture oocysts more rapidly compared to the other beads. Recovery efficiencies of DynabeadsTM, TCS Isolate® beads, and BioPoint Crypto- Bead ranged from 55 to 93% when tested against different sample matrices, with BioPoint CryptoBead resulting in the highest at 93% in reagent-grade water and DynabeadsTM at 55%, the lowest against clay samples. The Waterborne beads did not perform well on any samples, with recovery efficiencies ranging from 0 to 8%. Fluorescence microscopy analyses showed that both the IMS method and the sample matrix processed affect the quality of the membranes, with the cleanest samples for microscopy examination observed from BioPoint CryptoBead

Integrating reading and literature into content area curriculum through thematic units

The goals of this project include developing a way to efficiently teach the many required subjects in the overloaded elementary school day and incorporating litrature into content area curriculum

Determining appropriate approaches for using data in feature selection

Feature selection is increasingly important in data analysis and machine learning in big data era. However, how to use the data in feature selection, i.e. using either ALL or PART of a dataset, has become a serious and tricky issue. Whilst the conventional practice of using all the data in feature selection may lead to selection bias, using part of the data may, on the other hand, lead to underestimating the relevant features under some conditions. This paper investigates these two strategies systematically in terms of reliability and effectiveness, and then determines their suitability for datasets with different characteristics. The reliability is measured by the Average Tanimoto Index and the Inter-method Average Tanimoto Index, and the effectiveness is measured by the mean generalisation accuracy of classification. The computational experiments are carried out on ten real-world benchmark datasets and fourteen synthetic datasets. The synthetic datasets are generated with a pre-set number of relevant features and varied numbers of irrelevant features and instances, and added with different levels of noise. The results indicate that the PART approach is more effective in reducing the bias when the size of a dataset is small but starts to lose its advantage as the dataset size increases

Mitochondrial DNA haplotypes indicate two postglacial re-colonization routes of the spruce bark beetle Ips typographus through northern Europe to Scandinavia

Species in northern Europe re-colonized the region after the last glacial maximum via several routes, which could have lingering signatures in current intraspecific trait variation. The spruce bark beetle, Ips typographus, occurs across Europe, and biological differences have been found between southern and northern Scandinavian populations. However, the postglacial history of I. typographus in Scandinavia has not been previously studied at a fine geographical scale. Therefore, we collected specimens across northern Europe and analysed the genetic variation in a quite large mitochondrial fragment (698 bp). A high genetic diversity was found in some of the most northern populations, in the Baltic States, Gotland and central Europe. Detected genetic and phylogeographic structures suggest that I. typographus re-colonized Scandinavia via two pathways, one from the northeast and one from the south. These findings are consistent with the re-colonization history of its host plant, Picea abies. However, we observed low haplotype and nucleotide diversity in southern Scandinavian populations of I. typographus, indicating that (unlike P. abies) it did not disperse across the Baltic Sea in multiple events. Further, the divergence among Scandinavian populations was shallow, conflicting with a scenario where I. typographus expanded concurrently with its host plant from a 'cryptic refugium' in the northwest

Exploring precision polymers to fine-tune magnetic resonance imaging properties of iron oxide nanoparticles

The use of bio-polymers as stabilising agents for iron oxide-based negative magnetic resonance imaging (MRI) contrast agents has become popular in recent years, however the wide polydispersity of biologically-derived and commercially available polymers limits the ability to produce truly tuneable and reproducible behaviour, a major challenge in this area. In this work, stable colloids of iron oxide nanoparticles were prepared utilising precision-engineered bio-polymer mimics, poly(2-acrylamido-2-methylpropane sodium sulfonate) (P(AMPS)) polymers, with controlled narrow polydispersity molecular weights, as templating stabilisers. In addition to producing magnetic colloids with excellent MRI contrast capabilities (r2 values reaching 434.2 mM−1 s−1 at 25 °C and 23 MHz, several times higher than similar commercial analogues), variable field relaxometry provided unexpected important insights into the dynamic environment of the hydrated materials, and hence their exceptional MRI behaviour. Thanks to the polymer’s templating backbone and flexible conformation in aqueous suspension, nanocomposites appear to behave as “multi-core” clustered species, enhancing interparticle interactions whilst retaining water diffusion, boosting relaxation properties at low frequency. This clustering behaviour, evidenced by small-angle X-ray scattering, and strong relaxometric response, was fine-tuned using the well-defined molecular weight polymer species with precise iron to polymer ratios. By also showing negligible haemolytic activity, these nanocomposites exhibit considerable potential for MRI diagnostics

Hyperammonemia induces mitochondrial dysfunction and neuronal cell death

BACKGROUND & AIMS: In liver cirrhosis, astrocytic swelling is believed to be the principal mechanism of ammonia neurotoxicity leading to hepatic encephalopathy (HE). The role of neuronal dysfunction in HE is not clear. We aimed to explore the impact of hyperammonemia on mitochondrial function in primary co-cultures of neurons and astrocytes and in acute brain slices of cirrhotic rats using live cell imaging. METHODS: To primary co-cultures of astrocytes and neurons, low concentrations (1 and 5μM) of NH4Cl were applied. In rats with bile-duct ligation (BDL)-induced cirrhosis, a model known to induce hyperammonemia and minimal HE, acute brain slices were studied. One group of BDL rats were treated twice daily with the ammonia scavenger ornithine phenylacetate (OP, 0.3g/kg). Fluorescence measurements of changes in mitochondrial membrane potential (ΔΨm), cytosolic and mitochondrial reactive oxygen species (ROS) production, lipid peroxidation (LP) rates, and cell viability were performed using confocal microscopy. RESULTS: Neuronal cultures treated with NH4Cl exhibited mitochondrial dysfunction, ROS overproduction and reduced cell viability (27.8±2.3% and 41.5±3.7%, respectively) compared to untreated cultures (15.7±1.0%, both p<0.0001). BDL led to increased cerebral LP (p=0.0003) and cytosolic ROS generation (p<0.0001), which was restored by OP (both p<0.0001). Mitochondrial function was severely compromised in BDL resulting in hyperpolarization of ΔΨm with consequent overconsumption of ATP and augmentation of mitochondrial ROS production. Administration of OP restored ΔΨm. In BDL animals, neuronal loss was observed in hippocampal areas, which was partially prevented by OP. CONCLUSIONS: Our results elucidate that low-grade hyperammonemia in cirrhosis can severely impact on brain mitochondrial function. Profound neuronal injury was observed in hyperammonemic conditions, which was partially reversible by OP. This points towards a novel mechanism of HE development. LAY SUMMARY: The impact of hyperammonemia, a common finding in patients with liver cirrhosis, on brain mitochondrial function was investigated in this study. The results show that ammonia in concentrations commonly seen in patients induces severe mitochondrial dysfunction, overproduction of damaging oxygen molecules and profound injury and death of neurons in rat brain cells. These findings point towards a novel mechanism of ammonia-induced brain injury in liver failure and potential novel therapeutic targets

Challenges to conducting research with older people living in nursing homes

<p>Abstract</p> <p>Background</p> <p>Although older people are increasingly cared for in nursing homes towards the end of life, there is a dearth of research exploring the views of residents. There are however, a number of challenges and methodological issues involved in doing this. The aim of this paper is to discuss some of these, along with residents' views on taking part in a study of the perceptions of dignity of older people in care homes and make recommendations for future research in these settings.</p> <p>Methods</p> <p>Qualitative interviews were used to obtain the views on maintaining dignity of 18 people aged 75 years and over, living in two private nursing homes in South East London. Detailed field notes on experiences of recruiting and interviewing participants were kept.</p> <p>Results</p> <p>Challenges included taking informed consent (completing reply slips and having a 'reasonable' understanding of their participation); finding opportunities to conduct interviews; involvement of care home staff and residents' families and trying to maintain privacy during the interviews. Most residents were positive about their participation in the study, however, five had concerns either before or during their interviews. Although 15 residents seemed to feel free to air their views, three seemed reluctant to express their opinions on their care in the home.</p> <p>Conclusion</p> <p>Although we experienced many challenges to conducting this study, they were not insurmountable, and once overcome, allowed this often unheard vulnerable group to express their views, with potential long-term benefits for future delivery of care.</p

Is cannabis use a contributory cause of psychosis?

Objective: To assess whether cannabis use in adolescence and young adulthood is a contributory cause of schizophreniform psychosis in that it may precipitate psychosis in vulnerable individuals. Method: We reviewed longitudinal studies of adolescents and young adults that examined the relations between self-reported cannabis use and the risk of diagnosis with a psychosis or of reporting psychotic symptoms. We also reviewed studies that controlled for potential confounders, such as other forms of drug use and personal characteristics that predict an increased risk of psychosis. We assessed evidence for the biological plausibility of a contributory causal relation. Results: Evidence from 6 longitudinal studies in 5 countries shows that regular cannabis use predicts an increased risk of a schizophrenia diagnosis or of reporting symptoms of psychosis. These relations persisted after controlling for confounding variables, such as personal characteristics and other drug use. The relation did not seem to be a result of cannabis use to self-medicate symptoms of psychosis. A contributory causal relation is biologically plausible because psychotic disorders involve disturbances in the dopamine neurotransmitter systems with which the cannabinoid system interacts, as demonstrated by animal studies and one human provocation study. Conclusion: It is most plausible that cannabis use precipitates schizophrenia in individuals who are vulnerable because of a personal or family history of schizophrenia