Measurement properties of the Minimal Insomnia Symptom Scale (MISS) in an elderly population in Sweden

<p>Abstract</p> <p>Background</p> <p>Insomnia is common among elderly people and associated with poor health. The Minimal Insomnia Symptom Scale (MISS) is a three item screening instrument that has been found to be psychometrically sound and capable of identifying insomnia in the general population (20-64 years). However, its measurement properties have not been studied in an elderly population. Our aim was to test the measurement properties of the MISS among people aged 65 + in Sweden, by replicating the original study in an elderly sample.</p> <p>Methods</p> <p>Data from a cross-sectional survey of 548 elderly individuals were analysed in terms of assumptions of summation of items, floor/ceiling effects, reliability and optimal cut-off score by means of ROC-curve analysis and compared with self-reported insomnia criteria.</p> <p>Results</p> <p>Corrected item-total correlations ranged between 0.64-0.70, floor/ceiling effects were 6.6/0.6% and reliability was 0.81. ROC analysis identified the optimal cut-off score as ≥7 (sensitivity, 0.93; specificity, 0.84; positive/negative predictive values, 0.256/0.995). Using this cut-off score, the prevalence of insomnia in the study sample was 21.7% and most frequent among women and the oldest old.</p> <p>Conclusions</p> <p>Data support the measurement properties of the MISS as a possible insomnia screening instrument for elderly persons. This study make evident that the MISS is useful for identifying elderly people with insomnia-like sleep problems. Further studies are needed to assess its usefulness in identifying clinically defined insomnia.</p

?2-Microglobulin Amyloid Fibril-Induced Membrane Disruption Is Enhanced by Endosomal Lipids and Acidic pH

Although the molecular mechanisms underlying the pathology of amyloidoses are not well understood, the interaction between amyloid proteins and cell membranes is thought to play a role in several amyloid diseases. Amyloid fibrils of ?2-microglobulin (?2m), associated with dialysis-related amyloidosis (DRA), have been shown to cause disruption of anionic lipid bilayers in vitro. However, the effect of lipid composition and the chemical environment in which ?2m-lipid interactions occur have not been investigated previously. Here we examine membrane damage resulting from the interaction of ?2m monomers and fibrils with lipid bilayers. Using dye release, tryptophan fluorescence quenching and fluorescence confocal microscopy assays we investigate the effect of anionic lipid composition and pH on the susceptibility of liposomes to fibril-induced membrane damage. We show that ?2m fibril-induced membrane disruption is modulated by anionic lipid composition and is enhanced by acidic pH. Most strikingly, the greatest degree of membrane disruption is observed for liposomes containing bis(monoacylglycero)phosphate (BMP) at acidic pH, conditions likely to reflect those encountered in the endocytic pathway. The results suggest that the interaction between ?2m fibrils and membranes of endosomal origin may play a role in the molecular mechanism of ?2m amyloid-associated osteoarticular tissue destruction in DRA

Flowering Time Diversification and Dispersal in Central Eurasian Wild Wheat Aegilops tauschii Coss.: Genealogical and Ecological Framework

Timing of flowering is a reproductive trait that has significant impact on fitness in plants. In contrast to recent advances in understanding the molecular basis of floral transition, few empirical studies have addressed questions concerning population processes of flowering time diversification within species. We analyzed chloroplast DNA genealogical structure of flowering time variation in central Eurasian wild wheat Aegilops tauschii Coss. using 200 accessions that represent the entire species range. Flowering time measured as days from germination to flowering varied from 144.0 to 190.0 days (average 161.3 days) among accessions in a common garden/greenhouse experiment. Subsequent genealogical and statistical analyses showed that (1) there exist significant longitudinal and latitudinal clines in flowering time at the species level, (2) the early-flowering phenotype evolved in two intraspecific lineages, (3) in Asia, winter temperature was an environmental factor that affected the longitudinal clinal pattern of flowering time variation, and (4) in Transcaucasus-Middle East, some latitudinal factors affected the geographic pattern of flowering time variation. On the basis of palaeoclimatic, biogeographic, and genetic evidence, the northern part of current species' range [which was within the temperate desert vegetation (TDV) zone at the Last Glacial Maximum] is hypothesized to have harbored species refugia. Postglacial southward dispersal from the TDV zone seems to have been driven by lineages that evolved short-flowering-time phenotypes through different genetic mechanisms in Transcaucasus-Middle East and Asia

Transport of Pb and Zn by carboxylate complexes in basinal ore fluids and related petroleum-field brines at 100°C: the influence of pH and oxygen fugacity

It is well established through field observations, experiments, and chemical models that oxidation (redox) state and pH exert a strong influence on the speciation of dissolved components and the solubility of minerals in hydrothermal fluids. log [Image: see text] –pH diagrams were used to depict the influence of oxygen fugacity and pH on monocarboxylate- and dicarboxylate-transport of Pb and Zn in low-temperature (100°C) hydrothermal ore fluids that are related to diagenetic processes in deep sedimentary basins, and allow a first-order comparison of Pb and Zn transport among proposed model fluids for Mississippi Valley-type (MVT) and red-bed related base metal (RBRBM) deposits in terms of their approximate pH and [Image: see text] conditions. To construct these diagrams, total Pb and Zn concentrations and Pb and Zn speciation were calculated as a function of log [Image: see text] and pH for a composite ore-brine with concentrations of major elements, total sulfur, and total carbonate that approximate the composition of MVT and RBRBM model ore fluids and modern basinal brines. In addition to acetate and malonate complexation, complexes involving the ligands Cl(-), HS(-), H(2)S, and OH(- )were included in the model of calculated total metal concentration and metal speciation. Also, in the model, Zn and Pb are competing with the common-rock forming metals Ca, Mg, Na, Fe, and Al for the same ligands. Calculated total Pb concentration and calculated total Zn concentration are constrained by galena and sphalerite solubility, respectively. Isopleths, in log [Image: see text] –pH space, of the concentration of Pb and concentration of Zn in carboxylate (acetate + malonate) complexes illustrate that the oxidized model fluids of T. H. Giordano (in Organic Acids in Geological Processes, ed. E. D. Pittman and M. D. Lewan, Springer-Verlag, New York, 1994, pp. 319–354) and G. M. Anderson (Econ. Geol., 1975, 70, 937–942) are capable of transporting sufficient amounts of Pb (up to 10 ppm) and Zn (up to 100 ppm) in the form of carboxylate complexes to form economic deposits of these metals. On the other hand, the reduced ore fluid models of D. A. Sverjensky (Econ. Geol., 1984, 79, 23–37) and T. H. Giordano and H. L. Barnes (Econ. Geol., 1981, 76, 2200–2211) can at best transport amounts of Pb and Zn, as carboxylate complexes, that are many orders of magnitude below the 1 to 10 ppm minimum required to form economic deposits. Lead and zinc speciation (mol% of total Pb or Zn) in the model ore fluid was calculated at specific log [Image: see text] –pH conditions along the 100, 0.01, and 0.001 ppm total Pb and total Zn isopleths. Along the 100 ppm isopleth conditions are oxidized (∑SO(4 )>> ∑H(2)S) with Pb and Zn predominantly in the form of chloride complexes under acid to mildly alkaline conditions (pH from 3 to approximately 7.5), while hydroxide complexes dominate Pb and Zn speciation under more alkaline conditions. Sulfide complexes are insignificant under these oxidized conditions. For more reduced conditions along the 0.01 and 0.001 ppm isopleths chloride complexes dominate Pb and Zn speciation in the SO(4)(2- )field and near the SO(4)(2-)-reduced sulfur boundary from pH = 4 to approximately 7.5, while hydroxide complexes dominate Pb and Zn speciation under alkaline conditions above pH = 7.5 in the SO(4)(2- )field. In the most reduced fluids (∑H(2)S >> ∑SO(4)) along the 0.01 and 0.001 isopleths, sulfide complexes account for almost 100% of the Pb and Zn in the model fluid. Acetate (monocarboxylate) complexation is significant only under conditions of chloride and hydroxide complex dominance and its effect is maximized in the pH range 5 to 7, where it complexes 2 to 2.6% of the total Pb and 1 to 1.25% of the total Zn. Malonate (dicarboxylate) complexes are insignificant along all isopleths. The speciation results from this study show that deep formation waters characterized by temperatures near 100°C, high oxidation states and ∑H(2)S < 0.03 mg L(-1 )([Image: see text] < 10(-6)), high chlorinities (~ 100000 mg L(-1)), and high but reasonable concentrations of carboxylate anions can mobilize up to 3% of the total Pb and up to 1.3% of the total Zn as carboxylate complexes. Furthermore, these percentages, under the most favorable conditions, correspond to approximately 1 to 100 ppm of these metals in solution; concentrations that are adequate to form economic deposits of these metals. However, the field evidence suggests that all of these optimum conditions for carboxylate complexation are rarely met at the same time. A comparison of the composite ore fluid compositions from this study and modern brine data shows that the ore brines, corresponding to log [Image: see text] –pH conditions based on the Anderson (1975) and Giordano (1994) model fluids, are similar in many respects to modern, high trace-metal petroleum-field brines. The principal differences between modern high trace-metal brines and the composite ore fluids of Anderson (1975) and Giordano (1994) relate to their carboxylate anion content. The reported concentrations of monocarboxylate anions (∑monocbx) and dicarboxylate anions (Edicbx) in high trace-metal petroleum-field brines (< 1 to 300 mg L(-1 )and < 1 mg L(-1), respectively) are significantly lower than the concentrations assumed in the modelled brines of this study (∑monocbx = 7 700 mg L(-1 )and ∑dicbx = 300 mg L(-1)). There are also major differences in the corresponding total chloride to carboxylate ratio (∑m(Cl)/∑m(cbx)) and monocarboxylate to dicarboxylate ratio (∑m(monocbx)/∑m(dicbx)). Modern high trace-metal brines have much higher ∑m(Cl)/∑m(cbx )values and, therefore, the contribution of carboxylate complexes to the total Pb and Zn content in these modern brines is likely to be significantly less than the 1 to 3 percent for the composite ore fluids of Anderson (1975) and Giordano (1994). The composite ore-brine based on the Giordano and Barnes (1981) MVT ore fluid is comparable to the high salinity (> 170 000 mg L(-1 )TDS) subset of modern brines characterized by low trace-metal content and high total reduced sulfur (∑H(2)S). A comparison of the Sverjensky (1984) composite ore-brine with modern petroleum-field brines in terms of ∑H(2)S and Zn content, reveals that this ore fluid corresponds to a "border-type" brine, between modern high trace-metal brines and those with low trace-metal content and high ∑H(2)S. A brine of this type is characterized by values of ∑H(2)S, ∑Zn, and/or ∑Pb within or near the 1 to 10 mg L(-1 )range. Based on brine-composition data from numerous references cited in this paper, border-type brines do exist but are rare. The model results and field evidence presented in this study are consistent with other chemical simulation studies of carboxylate complexation in modern petroleum-field brines. Thus, it appears that carboxylate complexation plays a minor, if not insignificant, role as a transport mechanism for Pb and Zn in high salinity Na–Cl and Na–Ca–Cl basinal brines and related ore fluids