Cognitive Test Scores in UK Biobank: Data Reduction in 480,416 Participants and Longitudinal Stability in 20,346 Participants

UK Biobank includes 502,649 middle- and older-aged adults from the general population who have undergone detailed phenotypic assessment. The majority of participants completed tests of cognitive functioning, and on average four years later a sub-group of N = 20,346 participants repeated most of the assessment. These measures will be used in a range of future studies of health outcomes in this cohort. The format and content of the cognitive tasks were partly novel. The aim of the present study was to validate and characterize the cognitive data: to describe the inter-correlational structure of the cognitive variables at baseline assessment, and the degree of stability in scores across longitudinal assessment. Baseline cognitive data were used to examine the inter-correlational/factor-structure, using principal components analysis (PCA). We also assessed the degree of stability in cognitive scores in the subsample of participants with repeat data. The different tests of cognitive ability showed significant raw inter-correlations in the expected directions. PCA suggested a one-factor solution (eigenvalue = 1.60), which accounted for around 40% of the variance. Scores showed varying levels of stability across time-points (intraclass correlation range = 0.16 to 0.65). UK Biobank cognitive data has the potential to be a significant resource for researchers looking to investigate predictors and modifiers of cognitive abilities and associated health outcomes in the general population.     

Validation of the German Version of the Social Functioning Scale (SFS) for Schizophrenia

Deficits in social functioning are a core symptom of schizophrenia and an important criterion for evaluating the success of treatment. However, there is little agreement regarding its measurement. A common, often cited instrument for assessing self-reported social functioning is the Social Functioning Scale (SFS). The study aimed to investigate the reliability and validity of the German translation. 101 patients suffering from schizophrenia (SZ) and 101 matched controls (C) (60 male / 41 female, 35.8 years in both groups) completed the German version. In addition, demographic, clinical, and functional data were collected. Internal consistency was investigated calculating Cronbach’s alpha for SFS full scale (α: .81) and all subscales (α: .59-.88). Significant bivariate correlation coefficients were found between all subscales as well as between all subscales and full scale (p <.01). For the total sample, principal component analysis gave evidence to prefer a single-factor solution (eigenvalue ≥ 1) accounting for 48.5 % of the variance. For the subsamples, a two-component solution (SZ; 57.0 %) and a three-component solution (C; 65.6 %) fitted best, respectively. For SZ and C, significant associations were found between SFS and external criteria. The main factor “group” emerged as being significant. C showed higher values on both subscales and full scale. The sensitivity of the SFS was examined using discriminant analysis. 86.5% of the participants could be categorized correctly to their actual group. The German translation of the SFS turned out to be a reliable and valid questionnaire comparable to the original English version. This is in line with Spanish and Norwegian translations of the SFS. Concluding, the German version of the SFS is well suited to become a useful and practicable instrument for the assessment of social functioning in both clinical practice and research. It accomplishes commonly used external assessment scales.     

Correlation of structure and function in the Ca2+-ATPase of sarcoplasmic reticulum: a Fourier transform infrared spectroscopy (FTIR) study on the effects of dimethyl sulfoxide and urea

The effect of dimethyl sulfoxide (DMSO) on the structure of sarcoplasmic reticulum was analyzed by Fourier transform infrared (FTIR) and fluorescence spectroscopy. Exposure of sarcoplasmic reticulum vesicles to 35% DMSO (v/v) at 2 degrees C for several hours in a D2O medium produced no significant change in the phospholipid and protein Amide I regions of the FTIR spectra, but the intensity of the Amide II band decreased, presumably due to proton/deuterium exchange. At 40% to 60% DMSO concentration a shoulder appeared in the FTIR spectra at 1630 cm-1, that is attributed to the formation of new beta or random coil structures; irreversible loss of ATPase activity accompanied this change. At 70% DMSO concentration the intensity of the main Amide I band at 1639 cm-1 decreased and a new band appeared at 1622 cm-1, together with a shoulder at 1682 cm-1. These changes indicate an abrupt shift in the conformational equilibrium of Ca2+-ATPase from alpha to beta structure or to a new structure characterized by weaker hydrogen bonding. Decrease of ionization of aspartate and glutamate carboxyl groups in the presence of DMSO may also contribute to the change in intensity at 1622 cm-1. The changes were partially reversed upon removal of DMSO. Exposure of sarcoplasmic reticulum vesicles to 1.5 kbar pressure for 1 h at 2 degrees C in an EGTA-containing (low Ca2+) medium causes irreversible loss of ATPase activity, with the appearance of new beta structure, and abolition of the Ca2+-induced fluorescence response of FITC covalently bound to the Ca2+-ATPase; DMSO (35%) stabilized the Ca2+-ATPase against pressure-induced changes in structure and enzymatic activity, while urea (0.8 M) had the opposite effect.     

Starch Removal from Potato Tuber Sections

Heating plant sections at 90 C with 0.5% aqueous ammonium oxalate is required to remove pectins. When applied to tissues rich in starch such as potato, this step produces heavy dextrinization of the starch which hinders subsequent evaluation of the extinction values of the cell walls. To overcome this a method has been devised to brush away the starch granules from the sections with a thin paint brush, just after paraffin removal by xylene. The slide is then processed as usual: pectins are removed by heat treatment, cell walls are stained with PAS and the stain intensity can be evaluated by photometry.     

Covalent labeling of the cytoplasmic or luminal domains of the sarcoplasmic reticulum Ca(2+)-ATPase with fluorescent azido dyes.

Sarcoplasmic reticulum (SR) vesicles were incubated with azido derivatives of Cascade blue (ACB), Lucifer yellow (ALY), 2,7-naphthalene-disulfonic acid (ANDS), and fluorescein (AF) for 0.1-24 h at 2 degrees C. All four dyes gave intense reaction with the cytoplasmic domain of the Ca(2+)-ATPase on photoactivation after brief incubation. The penetration of the dyes into the luminal space of the SR was determined after centrifugation through Sephadex microcolumns to remove the external dye, followed by photolabeling and gel electrophoresis of the photolabeled proteins. The reaction of ACB and ANDS with the Ca(2+)-ATPase and with calsequestrin increased progressively during incubation up to 24 h indicating their slow accumulation in the luminal space, while ALY and AF did not show significant penetration into the vesicles. The distribution of the covalently attached ACB in the Ca(2+)-ATPase was tested by tryptic proteolysis after labeling exclusively from the outside (OS), from the inside (IS) or from both sides (BS). In all cases intense ACB fluorescence was seen in the A fragment with inhibition of ATPase activity. In the OS preparations the A1, while in IS the A2 fragment was more intensely labeled. There was no significant incorporation of ACB into the region of B fragment identified by FITC fluorescence. The crystallization of the Ca(2+)-ATPase by EGTA + decavanadate was completely inhibited in the BS samples after labeling either in the Ca2E1 or E2V conformation. There was no inhibition of crystallization in the OS preparations. In the IS preparations labeled in the Ca2E1 state the crystallization was impaired, while in the E2V state there was only slight disorganization of the crystals. The total amount of ACB photoincorporated into SR proteins after incubation for 24 h was 1.75 nmol/mg protein; 2/3 of this labeling occurred from the outside and 1/3 from the inside. Similar level of labeling was obtained in media that stabilize the E1 or the E2 conformation of the Ca(2+)-ATPase.     

Characteristics of a Bacteriocin Derived from Streptococcus faecalis var. zymogenes Antagonistic to Diplococcus peumoniae

A bacteriocin-producing strain of Streptococcus faecalis var. zymogenes (E-1) was isolated from clinical material (conjunctiva). The active substance differed from bacteriocins described by other investigators primarily in its spectrum of antibacterial activity, especially by its marked inhibition of Diplococcus pneumoniae. The E-1 bacteriocin also inhibited nonhemolytic strains of enterococci as well as one-third of the Viridans group of streptococcal strains investigated. The degree of inhibition, however, as indicated by the size of the zones against the latter organisms, was significantly reduced. No activity was detected against any of the strains belonging to the following groups of bacteria: hemolytic enterococci, beta-hemolytic streptococci, nonhemolytic streptococci, staphylococci, and various gram-negative species. Similarly, three strains each of Bacillus cereus and Listeria monocytogenes and one strain of Erysipelothrix insidiosa were not inhibited. The bacteriocin was able to diffuse through bacterial membranes as well as cellulose dialyzer tubing. It was inactivated by heating to 80 C for 20 min but resisted inactivation by either trypsin or chloroform.     

Processing Stripping Film Autoradiographs of Citrus Buds; Avoidance of Entrapped Air between Tissues and Developed Emulsion

Autoradiography was used on paraffin sections for investigating DNA synthesis in vegetative and flower buds of Citrus sinensis (L.) Osbeck. We preferred stripping film to liquid emulsion to obtain a more uniform thickness of the silver grain layer, as this would not vary more than ±10%. Furthermore, Baserga and Nemeroff (1962) have observed a lower sensitivity of fluid emulsion in comparison to stripping film together with occasionally erratic grain count and a slightly higher incidence of mechanical fogging. However, on using the customary procedure it was found that close contact between the surface of the section and the developed emulsion was not maintained when dehydration and clearing was done in the usual manner. The following modifications were therefore introduced to prevent the formation of air pockets between these two layers.     

Emerging views on the structure and dynamics of the Ca2(+)-ATPase in sarcoplasmic reticulum

The ATP-dependent Ca2+ transport in sarcoplasmic reticulum involves transitions between several structural states of the Ca2(+)-ATPase, that occur without major changes in the secondary structure. The rates of these transitions are modulated by the lipid environment and by interactions between ATPase molecules. Although the Ca2(+)-ATPase restricts the rotational mobility of a population of lipids, there is no evidence for specific interaction of the Ca2(+)-ATPase with phospholipids. Fluorescence polarization and energy transfer (FET) studies, using site specific fluorescent indicators, combined with crystallographic, immunological and chemical modification data, yielded a structural model of Ca2(+)-ATPase in which the binding sites of Ca2+ and ATP are tentatively identified. The temperature dependence of FET between fluorophores attached to different regions of the ATPase indicates the existence of 'rigid' and 'flexible' regions within the molecule characterized, by different degrees of thermally induced structural fluctuations.     

Cyclopiazonic acid is a specific inhibitor of the Ca2+-ATPase of sarcoplasmic reticulum

The mycotoxin, cyclopiazonic acid (CPA), inhibits the Ca2+-stimulated ATPase (EC 3.6.1.38) and Ca2+ transport activity of sarcoplasmic reticulum (Goeger, D. E., Riley, R. T., Dorner, J. W., and Cole, R. J. (1988) Biochem. Pharmacol. 37, 978-981). We found that at low ATP concentrations (0.5-2 microM) the inhibition of ATPase activity was essentially complete at a CPA concentration of 6-8 nmol/mg protein, indicating stoichiometric reaction of CPA with the Ca2+-ATPase. Cyclopiazonic acid caused similar inhibition of the Ca2+-stimulated ATP hydrolysis in intact sarcoplasmic reticulum and in a purified preparation of Ca2+-ATPase. Cyclopiazonic acid also inhibited the Ca2+-dependent acetylphosphate, p-nitrophenylphosphate and carbamylphosphate hydrolysis by sarcoplasmic reticulum. ATP protected the enzyme in a competitive manner against inhibition by CPA, while a 10(5)-fold change in free Ca2+ concentration had only moderate effect on the extent of inhibition. CPA did not influence the crystallization of Ca2+-ATPase by vanadate or the reaction of fluorescein-5'-isothiocyanate with the Ca2+-ATPase, but it completely blocked at concentrations as low as 1-2 mol of CPA/mol of ATPase the fluorescence changes induced by Ca2+ and [ethylenebis(oxyethylenenitrilo)]tetraacetic acid (EGTA) in FITC-labeled sarcoplasmic reticulum and inhibited the cleavage of Ca2+-ATPase by trypsin at the T2 cleavage site in the presence of EGTA. These observations suggest that CPA interferes with the ATP-induced conformational changes related to Ca2+ transport. The effect of CPA on the sarcoplasmic reticulum Ca2+-ATPase appears to be fairly specific, since the kidney and brain Na+,K+-ATPase (EC 3.6.1.37), the gastric H+,K+-ATPase (EC 3.6.1.36), the mitochondrial F1-ATPase (EC 3.6.1.34), the Ca2+-ATPase of erythrocytes, and the Mg2+-activated ATPase of T-tubules and surface membranes of rat skeletal muscle were not inhibited by CPA, even at concentrations as high as 1000 nmol/mg protein.