Preliminary classification and ecology of dry grassland communities on Ölands Stora Alvar (Sweden)

Four plant community types are described for Öland's Stora Alvar, the limestone plateau of South Öland and preliminary classified syntaxonomically:
(1) Crepis pumila – Allium alvarense ass. (2) Helianthemum oelandicum – Galium oelandicum ass. (3) Gypsophila fastigiata – Globularia vulgaris ass. and (4) Veronica spicata – Avenula pratensis ass. (with two subassociations, the Sedum reflexum and Galium boreale subass.). The ecology of these types is discussed with emphasis on soil depth, frost perturbation and the combined effects of summer drought and grazing intensity.
Various endemic taxa appear to be good character species for the community types described. The typical local ecology of some common species is discussed with the suggestion that they might have formed endemic ecotypes which should be further investigated.
The communities described are very rich in cryptogams. The floristic variation as expressed by the cryptogamic species composition shows largely the same pattern as that shown by the phanerogams.     

Liprin beta 1, a member of the family of LAR transmembrane tyrosine phosphatase-interacting proteins, is a new target for the metastasis-associated protein S100A4 (Mts1)

Metastasis-associated protein S100A4 (Mts1) induces invasiveness of primary tumors and promotes metastasis. S100A4 belongs to the family of small calcium-binding S100 proteins that are involved in different cellular processes as transducers of calcium signal. S100A4 modulates properties of tumor cells via interaction with its intracellular targets, heavy chain of non-muscle myosin and p53. Here we report identification of a new molecular target of the S100A4 protein, liprin beta1. Liprin beta1 belongs to the family of leukocyte common antigen-related (LAR) transmembrane tyrosine phosphatase-interacting proteins that may regulate LAR protein properties via interaction with another member of the family, liprin alpha1. We showed by the immunoprecipitation analysis that S100A4 interacts specifically with liprin beta1 in vivo. Immunofluorescence staining demonstrated the co-localization of S100A4 and liprin beta1 in the cytoplasm and particularly at the protrusion sites of the plasma membrane. We mapped the S100A4 binding site at the C terminus of the liprin beta1 molecule between amino acid residues 938 and 1005. The S100A4-binding region contains two putative phosphorylation sites by protein kinase C and protein kinase CK2. S100A4-liprin beta1 interaction resulted in the inhibition of liprin beta1 phosphorylation by both kinases in vitro.     

Subproteomics: identification of plasma membrane proteins from the yeast Saccharomyces cerevisiae

As a consequence of their poor solubility during isoelectric focusing, integral membrane proteins are generally absent from two-dimensional gel proteome maps. In order to analyze the yeast plasma membrane proteome, a plasma membrane purification protocol was optimized in order to reduce contaminating membranes and cytosolic proteins. Specifically, the new fractionation scheme largely depleted the plasma membrane fraction of cytosolic proteins by deoxycholate stripping and ribosomal proteins by sucrose gradient flotation. The plasma membrane complement was resolved by two-dimensional electrophoresis using the cationic detergent cetyl trimethyl ammonium bromide in the first, and sodium dodecyl sulfate in the second dimension, and fifty spots were identified by matrix-assisted laser desorption/ionization-time of flight mass spectometry. In spite of the presence of still contaminating ribosomal proteins, major proteins corresponded to known plasma membrane residents, the ABC transporters Pdr5p and Snq2p, the P-type H(+)-ATPase Pma1p, the glucose transporter Hxt7p, the seven transmembrane-span Mrh1p, the low affinity Fe(++) transporter Fet4p, the twelve-span Ptr2p, and the plasma membrane anchored casein kinase Yck2p. The four transmembrane-span proteins Sur7p and Nce102p were also present in the isolated plasma membranes, as well as the unknown protein Ygr266wp that probably contains a single transmembrane span. Thus, combining subcellular fractionation with adapted two-dimensional electrophoresis resulted in the identification of intrinsic plasma membrane proteins.     

Underestimation of Risk Due to Exposure Misclassification

Aim. Exposure misclassification constitutes a major obstacle when developing dose-response relationships for risk assessment. A non-differentional error results in underestimation of the risk. If the degree of misclassification is known, adjustment may be achieved by sensitivity analysis. The purpose of this study was to examine the full magnitude of measurement error in determining the prenatal exposure to methylmercury. Materials and methods. We used data from a prospective study of a Faroese birth cohort. Two biomarkers of methylmercury exposure were available, i.e., the mercury concentrations in cord blood and in maternal hair (sampled at the time of parturition). The laboratory imprecision on both chemical analyses was thought to be below 5% (coefficient of variation, CV). As a third exposure parameter, we used the dietary questionnaire response on frequency of whale meat dinners. Factor analysis and structural equation analysis were applied to assess the full extent of the imprecision. Results. The calculated total imprecision much exceeded the known laboratory variation: the CV was 28–30% for the cord-blood concentration and 52–55% for the maternal hair concentration. The dietary questionnaire response was even more imprecise. Conclusions. These findings illustrate that measurement error may be greatly underestimated if judged solely from reproducibility or laboratory quality data. Adjustment by sensitivity analysis is meaningful only if realistic measurement errors are applied. When exposure measurement errors are overlooked or underestimated, decisions based on the precautionary principle will not appropriately reflect the degree of precaution that was intended.     

Benchmark dose calculation from epidemiological data

A threshold for dose-dependent toxicity is crucial for standards setting but may not be possible to specify from empirical studies. Crump (1984) instead proposed calculating the lower statistical confidence bound of the benchmark dose, which he defined as the dose that causes a small excess risk. This concept has several advantages and has been adopted by regulatory agencies for establishing safe exposure limits for toxic substances such as mercury. We have examined the validity of this method as applied to an epidemiological study of continuous response data associated with mercury exposure. For models that are linear in the parameters, we derived an approximative expression for the lower confidence bound of the benchmark dose. We find that the benchmark calculations are highly dependent on the choice of the dose-effect function and the definition of the benchmark dose. We therefore recommend that several sets of biologically relevant default settings be used to illustrate the effect on the benchmark results and to stimulate research that will guide an a priori choice of proper default settings.     

Adenosine stimulated postimplantational regeneration of 5-adenine nucleotides in rabbit kidney grafts

The ability to regenerate the adenylate content in renal tissue appears to fail in rabbit kidney grafts, cold stored for 24 hours. The post implantational adenylate regeneration which did not occur, took place within the first lo minutes of re-established circulation. Thirty and sixty minutes of re-vascularization did not give any additional adenylate synthesis. The presence of adenosine (2.5 mM) in the preservation fluid, and that taken up by the kidney tissue during in vitro storage, brought about a significant increase in adenylate regeneration during the postimplantational period, independennt of a parallel increase in renal blood flow, and irrespective of the fact that adenosine did not show any adenylate preserving effect in vitro. The present results suggest that in long-term stored rabbit kidney grafts there occurs a relative postischaemic lack of intracellular available purine precursors. Owing to the filtration inhibiting effect of adenosine a study of the correlation between kidney function and adenylate regeneration was not possible.     

The advantages of occupational therapy in oral hygiene measures for institutionalised elderly adults

Objective: To investigate a new method in teaching and supervising tooth and denture brushing activities by employing occupational therapy techniques. Materials and methods: Sixty‐one residents, 44 women and 17 men, with an average age of 85.7 ± 6.6 years (range 72–97 years) living in a Long‐Term Care home (LTC) in Geneva were enrolled in a randomised controlled trial. They were divided at random into experimental (EG) and control groups (CG) with matched age and sex distribution. Two subjects passed away during the 3‐month experimental period. Following medical history, plaque scores and tooth brushing habits were evaluated within the context of a comprehensive clinical assessment. Furthermore, a Mini Mental State and a vision test were taken. Based on the results of these health assessments both the EG and the CG were divided into an ‘assisted’ (IA) and an ‘independent‘ (II) subgroup. In the EG, tooth brushing was initially taught and in the IA monitored and re‐educated once a week by an occupational therapist. In contrast, the CG‐IA group received a weekly placebo activity such as manicure by the same person. Results: From the individual movements taught and monitored by the occupational therapist, opening a tube of toothpaste (n.s.) and denture brushing (p < 0.05) were performed more independently after 3 months. Both the occupational therapy and the placebo activity led to a significant improvement in oral (p < 0.01 and 0.05) and in denture hygiene (p < 0.001 and 0.05). From all participants, the EG‐IA subgroup presented the most significant amelioration in plaque (p < 0.01) and denture hygiene scores (p < 0.001). This group consisted mostly of subjects with an impaired cognitive state. Conclusions: Despite the marked placebo effect, the results indicate that occupational therapy is particularly useful to improve the oral and denture hygiene in dependent and cognitively impaired LTC residents and may promote their autonomy in the execution of activities of daily life such as denture brushing.