Normal values of blood pressure self-measurement in view of the 1999 World Health Organization-International Society of Hypertension guidelines

New guidelines for the management of hypertension have been published in 1999 by the World Health Organization (WHO) and the International Society of Hypertension (ISH). The WHO/ISH Committee has adopted in principle the definition and classification of hypertension provided by the JNC VI (1997). The new classification defines a blood pressure of 120/80 mm Hg as optimal and of 130/85 mm Hg as the limit between normal and high-normal blood pressure. It is unclear which self-measured home blood pressure values correspond to these office blood pressure limits. In this study we reevaluated data from our Dübendorf study to determine self-measured blood pressure values corresponding to optimal and normal office blood pressure using the percentiles of the (office and home) blood pressure distributions of 503 individuals (age, 20 to 90 years; mean age, 46.5 years; 265 men, 238 women). Self-measured blood pressure values corresponding to office values of 130/85 mm Hg and 120/80 mm Hg were 124.1/79.9 mm Hg and 114.3/75.1 mm Hg. Thus, we propose 125/80 mm Hg as a home blood pressure corresponding to an office blood pressure of 130/85 mm Hg (WHO 1999: normal) and 115/75 mm Hg corresponding to 120/80 mm Hg (optimal). Am J Hypertens 2000;13:940-943 © 2000 American Journal of Hypertension, Lt

Stability of bicontinuous cubic phases in ternary amphiphilic systems with spontaneous curvature

We study the phase behavior of ternary amphiphilic systems in the framework of a curvature model with non-vanishing spontaneous curvature. The amphiphilic monolayers can arrange in different ways to form micellar, hexagonal, lamellar and various bicontinuous cubic phases. For the latter case we consider both single structures (one monolayer) and double structures (two monolayers). Their interfaces are modeled by the triply periodic surfaces of constant mean curvature of the families G, D, P, C(P), I-WP and F-RD. The stability of the different bicontinuous cubic phases can be explained by the way in which their universal geometrical properties conspire with the concentration constraints. For vanishing saddle-splay modulus $\bar \kappa$, almost every phase considered has some region of stability in the Gibbs triangle. Although bicontinuous cubic phases are suppressed by sufficiently negative values of the saddle-splay modulus $\bar \kappa$, we find that they can exist for considerably lower values than obtained previously. The most stable bicontinuous cubic phases with decreasing $\bar \kappa < 0$ are the single and double gyroid structures since they combine favorable topological properties with extreme volume fractions.Comment: Revtex, 23 pages with 10 Postscript files included, to appear in J. Chem. Phys. 112 (6) (February 2000

Error estimates for solid-state density-functional theory predictions: an overview by means of the ground-state elemental crystals

Predictions of observable properties by density-functional theory calculations (DFT) are used increasingly often in experimental condensed-matter physics and materials engineering as data. These predictions are used to analyze recent measurements, or to plan future experiments. Increasingly more experimental scientists in these fields therefore face the natural question: what is the expected error for such an ab initio prediction? Information and experience about this question is scattered over two decades of literature. The present review aims to summarize and quantify this implicit knowledge. This leads to a practical protocol that allows any scientist - experimental or theoretical - to determine justifiable error estimates for many basic property predictions, without having to perform additional DFT calculations. A central role is played by a large and diverse test set of crystalline solids, containing all ground-state elemental crystals (except most lanthanides). For several properties of each crystal, the difference between DFT results and experimental values is assessed. We discuss trends in these deviations and review explanations suggested in the literature. A prerequisite for such an error analysis is that different implementations of the same first-principles formalism provide the same predictions. Therefore, the reproducibility of predictions across several mainstream methods and codes is discussed too. A quality factor Delta expresses the spread in predictions from two distinct DFT implementations by a single number. To compare the PAW method to the highly accurate APW+lo approach, a code assessment of VASP and GPAW with respect to WIEN2k yields Delta values of 1.9 and 3.3 meV/atom, respectively. These differences are an order of magnitude smaller than the typical difference with experiment, and therefore predictions by APW+lo and PAW are for practical purposes identical.Comment: 27 pages, 20 figures, supplementary material available (v5 contains updated supplementary material

Veränderung der Absorption ultraviolettdurchlässiger Gläser

Untersuchung von Ein-, Zwei-, Drei- und Vielstoffgläsern mit bestimmtem Fe- und Ti-Gehalt. - Feststellung, daß Alterung nicht, wie fast allgemein angenommen, durch den Übergang des Fe (II) in Fe (III) bedingt ist, sondern Veränderung des Grundglases selbst bedeutet. - Alterungsversuche mit spektral zerlegtem UV-Licht. - Es kann, je nach Wellenlänge, ein- und dasselbe Glas für ein UV-Gebiet undurchlässiger, für ein anderes durchlässiger machen. - Kein Unterschied zwischen der Alterung von Natrium- und Kalium-Gläsern

Membrane sodium-proton exchange and primary hypertension

Recent studies have revealed that an enhancement of sodium-proton exchange is a frequently observed ion transport abnormality in essential hypertension. An altered antiport activity not only is measurable in blood cells of hypertensive subjects ex vivo but also is detectable in skeletal muscle in vivo. Several lines of argument suggest that the altered antiport activity is not an epiphenomenon of hypertension: 1) the increased activity is found only in a subgroup of patients with high blood pressure, 2) it is not tightly correlated to the severity or duration of hypertension, and 3) high sodium-proton exchange activity persists over time and is not affected by antihypertensive treatment. Available evidence suggests that enhanced sodium-proton exchange is associated with or a cause for the structural alterations found in resistance vessels of hypertensive individuals (media hypertrophy) and left ventricular hypertrophy. This review summarizes some of the physiological properties and roles of the sodium-proton exchanger and discusses its kinetic properties in essential hypertension. Furthermore, the reasons for the enhanced antiport activity and its potential implications regarding the pathogenesis of hypertension are discussed

Platelet Na⁺-H⁺ exchanger activity in normotensive and hypertensive subjects: effect of enalapril therapy upon antiport activity

Objective: Primary hypertension has been reported to be associated with an enhancement of Na+-H+ exchange. However, details of the kinetic properties of the Na+-H+ exchanger in hypertensives and its dependence upon age and gender in normotensives are unknown. Participants: We determined the activity of the platelet Na+-H+ exchanger in 20 normotensives and 26 untreated primary hypertensives. Interventions: In eight hypertensive individuals antihypertensive treatment was interrupted for 1 week. Treatment for 6 weeks with a daily single dose of 10 mg enalapril decreased mean arterial pressure to 105.7 ± 11.6 mmHg. Methods: Platelets were loaded with the intracellular pH (pHi) indicator 2'-7'-bis-carboxyethyl-5(6)-carboxyfluorescein (BCECF) and acidified by propionic acid. Initial velocities of pH recovery were determined and used for calculation of maximum velocity (Vmax), baseline pHi and the pHi value for half maximal activation (pH0.5) of the Na+-H+ exchanger in each individual. Results: In normotensives, Vmax averaged 0.05 ± 0.01 dpHi/min independently of age, gender and actual diastolic blood pressure. In hypertensives, two different subgroups were defined bearing either low or high Na+-H+ exchange activity. Values of pHiexchange activity. Values of pH and pH0.5 were identical in all subgroups irrespective of Vmax. The twofold enhancement of Na+-H+ exchange in the second group was preserved in thrombin-stimulated platelets. Vmax values remained unaffected by enalapril treatment. Conclusions: Enhanced Na+-H+ exchange activity in hypertensives is primarily characterized by an increase in Vmax. This enhancement is refractory to antihypertensive treatment and therefore appears to be a relatively fixed parameter