High-energy anomaly in the angle-resolved photoemission spectra of Nd(2-x)Ce(x)CuO₄: evidence for a matrix element effect

We use polarization-dependent angle-resolved photoemission spectroscopy (ARPES) to study the high-energy anomaly (HEA) in the dispersion of Nd(2-x)Ce(x)CuO₄, x=0.123. We find that at particular photon energies the anomalous, waterfall-like dispersion gives way to a broad, continuous band. This suggests that the HEA is a matrix element effect: it arises due to a suppression of the intensity of the broadened quasiparticle band in a narrow momentum range. We confirm this interpretation experimentally, by showing that the HEA appears when the matrix element is suppressed deliberately by changing the light polarization. Calculations of the matrix element using atomic wave functions and simulation of the ARPES intensity with one-step model calculations provide further evidence for this scenario. The possibility to detect the full quasiparticle dispersion further allows us to extract the high-energy self-energy function near the center and at the edge of the Brillouin zone.

Reversal of the circular dichroism in angle-resolved photoemission from Bi2Te3

The helical Dirac fermions at the surface of topological insulators show a strong circular dichroism which has been explained as being due to either the initial-state spin angular momentum, the initial-state orbital angular momentum, or the handedness of the experimental setup. All of these interpretations conflict with our data from Bi(2)Te(3) which depend on the photon energy and show several sign changes. Our one-step photoemission calculations coupled to ab initio theory confirm the sign change and assign the dichroism to a final-state effect. Instead, the spin polarization of the photoelectrons excited with linearly polarized light remains a reliable probe for the spin in the initial state.

Correlation of electron self-energy with geometric structure in low-energy electron diffraction

In low-energy electron diffraction (LEED) studies of surface geometries where the energy dependence of the intensities is analyzed, the in-plane lattice parameter of the surface is usually set to a value determined by x-ray diffraction for the bulk crystal. In cases where it is not known, for instance in films that are incommensurate with the substrate, it is desirable to fit the in-plane lattice parameters in the same analysis as the perpendicular interlayer spacings. We show that this is not possible in a conventional LEED I(E) analysis because the inner potential, which is typically treated as an adjustable parameter, is correlated with the geometrical structure. Therefore, without having prior knowledge of the inner potential, it is not possible to determine the complete surface structure simply from LEED I(E) spectra, and the in-plane lattice parameter must be determined independently before the I(E) analysis is performed. This can be accomplished by establishing a more precise experimental geometry. Further, it is shown that the convention of omitting the energy dependency of the real part of the inner potential means geometrical LEED results cannot be trusted beyond a precision of approximately 0.01 Å.

Circular dichroism in the angle-resolved photoemission spectrum of the high-temperature Bi_{2}Sr_{2}CaCu_{2}O_{8+delta} superconductor: can these measurements be interpreted as evidence for time-reversal symmetry breaking?

We report first-principles computations of the angle-resolved photoemission response with circularly polarized light in Bi_{2}Sr_{2}CaCu_{2}O_{8+delta} for the purpose of delineating contributions to the circular dichroism resulting from distortions and modulations of the crystal lattice. Comparison with available experimental results shows that the measured circular dichroism from antinodal mirror planes is reproduced in quantitative detail in calculations employing the average orthorhombic crystal structure. We thus conclude that the existing angle-resolved photoemission measurements can be understood essentially within the framework of the conventional picture, without the need to invoke unconventional mechanisms.

Effect of symmetry distortions on photoelectron selection rules and spectra of Bi2Sr2CaCu2O8+delta

We derive photoelectron selection rules along the glide plane in orthorhombic Bi2Sr2CaCu2O8+delta (Bi2212). These selection rules explain the reversed intensity behavior of the shadow and the main band of the material as a natural consequence of the variating representation of the final state as a function of k(parallel). Our one-step simulations strongly support the structural origin of the shadow band but we also introduce a scenario for detecting antiferromagnetic signatures in low doping.

Experimental proof of a structural origin for the shadow fermi surface of Bi2Sr2CaCu2O8+delta

By combining surprising new results from a full polarization analysis of nodal angle-resolved photoemission data from pristine and modulation-free Bi(2)Sr(2)CaCu(2)O(8+delta) with structural information from LEED and ab initio one-step photoemission simulations, we prove that the shadow Fermi surface in these systems is of structural origin, being due to orthorhombic distortions from tetragonal symmetry present both in surface and bulk. Consequently, one of the longest standing open issues in the investigation of the Fermi surface of these widely studied systems finally meets its resolution.

Evolution of midgap states and residual three dimensionality in La2-xSrxCuO4

We carry out extensive first-principles doping-dependent computations of angle-resolved photoemission (ARPES) intensities in La2-xSrxCuO4 over a wide range of binding energies. Intercell hopping and the associated three dimensionality, which is usually neglected in discussing cuprate physics, is shown to play a key role in shaping the ARPES spectra. Despite the obvious importance of strong coupling effects (e.g., the presence of a lower Hubbard band coexisting with midgap states in the doped insulator), a number of salient features of the experimental ARPES spectra are captured to a surprising extent when kz dispersion is properly included in the analysis.

Patellofemoral relationships and cartilage breakdown

We evaluated the association between patellofemoral relationships and cartilage lesions in patients (age range 15-49) with anterior knee pain without patellar dislocation (n = 24) and in patients with isolated meniscal rupture without a high energy trauma (n = 21). The position of the patella was assessed from knee radiographs, and cartilage lesion was graded and mapped at arthroscopy. In subjects with lateral patellar cartilage lesion the patella tilted laterally (p < 0.01) and was clearly laterally displaced (p < 0.001), compared to those without patellar cartilage lesion. In subjects with central patellar cartilage lesion the patella located high according to the Insall-Salvati index (p < 0.01) and was somewhat laterally displaced (p < 0.05). Compared to subjects without cartilage lesion in the femoral trochlea, the patella was laterally displaced in subjects with lesion in the lateral trochlea (p < 0.001). In conclusion, our results suggest that specific malalignments predispose to patellofemoral cartilage lesion, but prospective studies are needed to confirm the finding.

The influence of EDTMP-concentration on the biodistribution of radio-lanthanides and 225-Ac in tumor-bearing mice. The ISOLDE Collaboration

High-resolution gamma spectroscopy was applied to measure simultaneously the biodistribution of carrier-free radionuclides of several lanthanides (141Ce, 145Sm, 149Gd, 167Tm) and 225Ac in tumor-bearing nude mice. Mixtures of the radiotracers were injected in solutions containing different concentrations of EDTMP (ethylenediaminetetramethylenephosphonic acid). The strong dependence of liver uptake on the ionic radius of the radio-lanthanides was confirmed for all tracers used. The ratios of radioactivity concentrated in tumour that concentrated in liver are strongly influenced by the EDTMP concentration, reaching values close to 10 for Tm, 3 for Sm, and 1 for Ac. The optimal EDTMP concentrations, giving highest tumor-to-liver ratios of enrichment, were between 1 and 10 mM for 100 microL injected volume for the animal model used in this experiment. In radionuclide therapy using EDTMP as ligands, close control of ligand concentration will be necessary.

Congestive heart failure in old age: prevalence, mechanisms and 4-year prognosis in the Helsinki Ageing Study

OBJECTIVE

To examine the prevalence, underlying diseases, abnormalities of left ventricular function and prognosis in congestive heart failure (CHF) of old age.

DESIGN

A population-based clinical and echocardiographic study with a 4-year mortality follow-up.

SETTING

University hospital.

SUBJECTS

Five hundred and one individuals born in 1904. 1909 and 1914 (367 women).

MAIN OUTCOME MEASURES

Presence of CHF by clinical and chest radiograph criteria: left ventricular size and systolic function by echocardiography; grade of aortic and mitral valve lesion by Doppler echocardiography; 4-year total and cardiovascular mortality.

RESULTS

Forty-one of 501 participants (8.2%) had CHF. Ischaemic heart disease (54%), hypertension (54%) and moderate-to-severe mitral or aortic valve disease (51%) were the main underlying conditions; 90% of patients had one or more of these diseases. Most individuals with CHF (28 of 39 patients, 72%) had normal left ventricular contractions at echocardiography. 'Diastolic CHF', defined as CHF with normal systolic left ventricular function and no regurgitant valve disease, was found in 51% (20 of 39 patients). The relative 4-year risk for death associated with CHF, adjusted for age and sex, was 2.1 (95% confidence interval 1.3-3.4) for all-cause mortality and 4.2 (CI 1.9-5.6) for cardiovascular mortality.

CONCLUSIONS

The prevalence of CHF in a population aged 75-86 years is approximately 8%. Ischaemic or valvular heart disease and hypertension are the main underlying conditions. At echocardiography, about 50% of the elderly with CHF have normal left ventricular systolic contractions in the absence of valve disease and an additional 20% have normal systolic function with mitral regurgitation. The presence of CHF doubles the age- and sex-adjusted risk of death from all causes, and quadruples the risk of cardiovascular death during 4-year follow-up.

Natural history of aortic valve stenosis of varying severity in the elderly

In a population sample of 501 persons aged 75 to 86 years, Doppler echocardiography uncovered moderate or severe aortic valve stenosis in 8.8% of women and 3.6% of men. Severe aortic valve stenosis predicted a four-fold-age- and sex-adjusted risk of death within 4 years of diagnosis, and mortality tended to be increased also with moderate lesions; mild aortic valve stenosis had a favorable outcome.

Calcific degeneration of the aortic valve in old age: is the development of flow obstruction predictable?

OBJECTIVE

Aortic valve calcification and stenosis become increasingly common with advancing age. This work aimed at assessing whether a time-dependent reduction of aortic valve area is detectable in an unselected elderly population and whether the rate of reduction can be predicted from clinical or biochemical characteristics.

DESIGN

A population-based prospective echocardiographic follow-up study.

SETTING

A university hospital.

SUBJECTS

In 1990, randomly selected persons born in 1904, 1909 and 1914 (total n = 501) underwent a Doppler echocardiographic study of aortic valve and biochemical tests of glucose, lipid and calcium metabolism. In 1993, echocardiography was repeated in 333 survivors of the original cohorts. These individuals constitute the present study population.

MAIN OUTCOME MEASURES

Three-year changes in the aortic valve area and velocity ratio (peak outflow tract velocity/peak aortic jet velocity) determined by Doppler echocardiography.

RESULTS

Aortic valve area decreased from a mean of 1.95 cm2 (95% confidence interval of mean, 1.88-2.03 cm2) to 1.78 cm2 (1.71-1.85 cm2) within 3 years (P < 0.001). Concomitantly, the velocity ratio decreased from 0.75 (0.73-0.77) to 0.68 (0.67-0.70) (P < 0.001). The changes in aortic valve area and velocity ratio were unrelated to age, sex, presence of hypertension, coronary artery disease or diabetes, and to all assessed biochemical characteristics. A weak positive statistical association was found between the decrease in aortic valve area and the body mass index at entry (r = 0.16, P < 0.01).

CONCLUSIONS

A time-dependent reduction of the aortic valve flow orifice can be demonstrated in persons representing the general elderly population. The deterioration of aortic valve function within a span of 3 years is neither clinically nor biochemically predictable. A longer follow-up may be necessary to identify the risk factors of aortic valve stenosis in old age.

Echocardiographic evidence of left ventricular hypertrophy in a general aged population

The purpose of this study was to measure the frequency of left ventricular (LV) hypertrophy in old age. Random subjects born in 1904, 1909, and 1914 (n = 501), and 76 born in 1920 to 1935 were studied. All subjects underwent clinical and echocardiographic investigation. An electrocardiogram was obtained in 449 subjects. Complete data for calculation of LV mass corrected for body size were available in 422 of the studied subjects (73%). LV hypertrophy was defined as calculated LV mass exceeding either an internal standard of the Helsinki Aging Study, earlier published limits from the Framingham Heart Study, or criteria from Devereux et al. LV wall thickness and mass were positively related to age. Hypertrophy was present in both sexes, the rate even exceeding 70% in the oldest cohort aged 85 to 86 years using the Framingham and Devereux limits. LV hypertrophy (LV mass exceeding defined limits after correction for body height) was significantly and independently related to age, systolic blood pressure, body mass index, and mitral regurgitation. A sustained apex beat, third heart sound, and electrocardiographic changes were significantly more frequent in the group with echocardiographic hypertrophy, although with considerable overlapping. The fourth heart sound was unrelated to hypertrophy. Use of age-independent criteria result in an extremely high prevalence of LV hypertrophy in old age. This is partly due to age-related diseases increasing LV mass, but also partly to an independent effect of age. The usefulness of clinical signs for detecting LV hypertrophy is limited in old age.

Factors associated with calcific aortic valve degeneration in the elderly

This study aimed at identifying factors influencing aortic valve calcification in old age. Echocardiographic and Doppler characteristics of the aortic valve were compared with possible clinical and biochemical predictors in 501 people aged 75-86 years and in 76 aged 55-71. Slight calcification was seen in 222 people (40%) and severe calcification in 72 (13%); 21 people had moderate or severe aortic stenosis. Age (P = 0.000) and serum parathyroid hormone (P = 0.015) were higher and body mass index lower (P = 0.002) in the presence of aortic valve calcification. In multivariate analysis, age (P = 0.000), hypertension (P = 0.005) and body mass index (P = 0.005) were independent predictors of aortic valve calcification, and age (P = 0.022) and serum ionized calcium (P = 0.037) of valve stenosis. The odds ratio (95% confidence interval) for valve calcification was 1.89 (1.42-2.50) for a 10-year increase in age, 1.74 (1.19-2.55) in the presence of hypertension, and 1.39 (1.10-1.76) for a 5 kg.m-2 decrease in body mass index. Sex, smoking, diabetes, serum lipids and insulin were unrelated to valvular calcification. These data suggest that leanness and a history of hypertension increase the likelihood of senile aortic valve calcification. Calcium metabolism may also be of significance. The mechanisms of these associations deserve further study.

Predictors of left ventricular mass in old age: an echocardiographic, clinical and biochemical investigation of a random population sample

The potential predictors of left ventricular mass in old age were studied in a random sample of people born in 1904, 1909, 1914 (n = 501) and 1920-35 (n = 76). Data on the left ventricle with mass calculation, quantitative data on valve disorders and biochemical data were collected. Left ventricular mass (corrected for height) was positively related to male gender, age, body mass index and systolic blood pressure. It was also significantly higher in the presence of aortic valve calcification, a low velocity ratio (indicating aortic valve obstruction), and aortic or mitral regurgitation. In men, left ventricular mass was higher in the presence of coronary artery disease and inversely related to serum high density lipoprotein cholesterol. In multivariate analysis, independent predictors of left ventricular mass without sex interaction were age (standardized coefficient beta = 0.23, P = 0.000), male gender (beta = 0.38, P = 0.000), body mass index (beta = 0.22, P = 0.000), systolic blood pressure (beta = 0.21, P = 0.000), velocity ratio (beta = -0.11, P = 0.010), detectable aortic regurgitation (beta = 0.11, P = 0.014) and moderate-to-severe mitral regurgitation (beta = 0.21, P = 0.000). Thus, the increase in left ventricular mass with age can largely be related to discrete predictors. The impact of valve disorders is substantial.

Prevalence of aortic valve abnormalities in the elderly: an echocardiographic study of a random population sample

OBJECTIVES

This study was undertaken to elucidate the prevalence of aortic valve abnormalities in the elderly.

BACKGROUND

The age of persons treated actively for valve disorders is increasing. More information is needed about the prevalence of aortic valve disease in old age.

METHODS

Randomly selected men and women in the age groups 75 to 76, 80 to 81 and 85 to 86 years (n = 501) participating in the Helsinki Ageing Study were studied with imaging and Doppler echocardiography. Additionally, 76 persons 55 to 71 years of age were included. The systolic aortic valve area was calculated by the continuity equation. The velocity ratio (peak velocity in the left ventricular outflow tract/peak velocity across the aortic valve) was a supplementary criterion for aortic stenosis. Valve regurgitation and cusp calcification were assessed visually.

RESULTS

Evaluation of the aortic valve was possible in 552 persons (96%). Mild calcification was found in 222 (40%) and severe calcification in 72 (13%). Two persons (0.4%) had an aortic valve prosthesis. Critical native valve stenosis (calculated aortic valve area < or = 0.8 cm2 and velocity ratio < or = 0.35) was found in 12 persons (2.2%). Six of these were symptomatic and potentially eligible for valvular surgery. All persons with aortic valve stenosis were in the three oldest age groups. The prevalence of critical aortic valve stenosis was 2.9% (95% confidence interval 1.4% to 5.1%) in the group 75 to 86 years of age. Aortic regurgitation, mostly mild, was found in 29% of the entire study cohort.

CONCLUSIONS

Calcific aortic valve stenosis constitutes a significant health problem in the elderly. Only a minority of those with potentially operable aortic valve stenosis undergo surgery.

Exclusion of coronary artery disease by exercise thallium-201 tomography in patients with aortic valve stenosis

In many patients with valvular aortic stenosis (AS), management decisions may be possible without invasive studies if coexistent coronary artery disease (CAD) can be ruled out noninvasively. The use of thallium-201 single-photon emission computed tomography to the exclusion of CAD was studied in 44 patients aged 41 to 78 years with AS. In addition to cardiac catheterization and selective coronary angiography, patients underwent a cardiac ultrasound study and thallium-201 myocardial perfusion imaging at rest and after bicycle ergometer exercise. Two thirds of the patients had critical AS (valve area index less than or equal to 0.5 cm2/m2) but none had left ventricular systolic dysfunction. Twenty-one patients had angiographically significant CAD (greater than or equal to 50% diameter stenosis in greater than or equal to 1 coronary artery), whereas 23 had either a fully normal angiogram (n = 17) or mild (less than 50%) stenoses (n = 6). Each patient with significant CAD had an abnormal thallium-201 tomogram, either a strictly segmental perfusion defect (n = 19), or a patchy nonsegmental abnormality (n = 2); however, 10 of 23 patients free of significant CAD had similar results. Thus, the sensitivity and specificity of an abnormal scintigram were 100 and 57%, respectively. If only segmental perfusion defects typical of CAD had been considered abnormal, then the sensitivity of the test would have been 90% and the specificity 70%. Patients with false abnormal scintigrams had more severe AS and more angiographically nonsignificant CAD than those with true normal findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial colonization of intravascular catheters and anergy to recall skin antigens

The skin reactivity of 46 ICU patients was tested against recall antigens: mumps, candidin, streptokinase-streptodornase, and purified protein derivative of tuberculin. At the same time, the intravascular catheters used in these patients were cultured with a semiquantitative method. Twelve patients did not react to any of the antigens. There was a statistically significant association between anergy in skin testing and lethal outcome of the current illness. Catheter cultures from 11 patients yielded over 15 colony-forming units of bacteria. No association was found between positive catheter cultures and skin reactivity to any of the antigens. This indicates that catheter colonization is independent of host factors reflected by skin testing and supports the view that transmission of microorganisms into catheters is more important than poor host defense in the initiation of catheter-related infections.

Timolol and a hydrochlorothiazide-amiloride combination in the treatment of essential hypertension in young and middle-aged patients: a comparative study with once-daily administration

The antihypertensive effects of timolol administered once daily and a combination diuretic were compared in 45 young and middle-aged hypertensive patients. Both treatments significantly reduced lying and standing systolic and diastolic blood pressures as compared to placebo. There were no significant differences between blood pressure reductions after treatment with timolol or with the diuretic. There was a slight negative correlation between the decrease of diastolic blood pressure during timolol treatment and patient age. Serum potassium decreased slightly but significantly during treatment with the diuretic.

Effect of cardiopulmonary resuscitation-induced stress on cell-mediated immunity

Functions of cell-mediated immunity were studied from 11 patients after cardiovascular resuscitation and from matched controls who were simultaneously under observation. The resuscitated patients were anergic to recall skin antigens (93% negative) as compared to the controls (62%) (p less than 0.01). The anergic state correlated with the outcome of the patients. Lymphocyte numbers did not differ between these groups, but the number of T cells was significantly decreased, and B cells and granulocytes was increased in resuscitated patients. Lymphocytes from resuscitated patients responded to mitogenic stimulation although the responses were lower than those of the controls. Decreased lymphocyte responses were partly due to serum factor(s) which were not attributable to serum cortisol concentration. In addition the findings favour a change in the compartmentalization of lymphocyte subsets resulting in increased number of suppressor cells and/or increased sensitivity of lymphocytes to suppressive humoral factor(s) in the circulation. The anergy in skin evidently represents the final outcome of the dysfunction of several arms of cell mediated immunity.