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Biomedical subjects

U Becker

Publications and source records attributed to U Becker.

At least 19 recordsLinked to original sources
PubMed2002

4sigma(-1) inner valence photoionization dynamics of NO derived from photoelectron-photoion angular correlations.

A complete description of the 4sigma photoionization dynamics of NO has been derived from angle resolved photoelectron-photoion-coincidence experiments. The combination of measurements performed with linearly and circularly polarized light has made it possible to obtain a unique set of complex dipole matrix elements. A comparison with multichannel-Schwinger-configuration-interaction calculations shows good agreement in the general shapes of the angular distributions due to the correct description of the main components and phase differences. Still, many transition moments agree only qualitatively.

Journal Article↗
PubMed2002

Direct probe of the bent and linear geometries of the core-excited Renner-Teller pair states by means of the triple-ion-coincidence momentum imaging technique.

The doubly degenerate core-excited Pi state of CO2 splits into two due to static Renner-Teller effect. Using the triple-ion-coincidence momentum imaging technique and focusing on the dependence of the measured quantities on the polarization of the incident light, we have probed, directly and separately, the linear and bent geometries for the B1 and A1 Renner-Teller pair states, as a direct proof of the static Renner-Teller effect.

Journal Article↗
PubMed2002

Elevated arterial compliance in patients with cirrhosis is not related to arterial endothelin-1.

BACKGROUND: Patients with cirrhosis and portal hypertension have a hyperkinetic systemic circulation. A number of circulating vasoactive peptides, including endothelin-1 (ET-1), are elevated and, recently, increased arterial compliance has been described in these patients. The aim of the present study was to investigate a potential relation between altered arterial compliance and arterial ET-1 in patients with cirrhosis. As ET-1 may be manipulated by somastostatin, the study includes infusion of octreotide in a subset of patients. METHODS: A total of 67 patients with cirrhosis and 27 controls were studied during a haemodynamic investigation. Arterial ET-1 was determined by two different radioimmunoassays and arterial compliance was determined as the stroke volume/pulse pressure index. RESULTS: Arterial compliance was elevated by 32%-40% in the cirrhotic patients as compared to the controls (P < 0.005). Arterial ET-1 was elevated by 26%-170% in the cirrhotic patients (P<0.001). No significant relationships could be established between arterial compliance and arterial ET-1 (r = -0.15 to 0.23, ns). Intravenous bolus injection and infusion of octreotide (100 pg + 100 microg/h, n = 9) did not significantly change either arterial compliance or arterial ET-1. CONCLUSION: Both arterial compliance and arterial ET- I are substantially elevated in patients with cirrhosis, but there is no significant relation between arterial compliance and arterial ET- I in these patients.

Adult↗
PubMed2001

[Beer, wine, spirits and mortality].

A population based cohort study investigates the association between alcohol intake and mortality from all causes, coronary heart disease and cancer. The design is prospective with baseline assessment of intake of beer, wine and spirits, smoking habits, educational level, physical activity, and body mass index and a total of 257,859 person-years follow-up on mortality. A total of 4,833 participants died, of these 1,075 from coronary heart disease and 1,552 of cancer. Compared with non-drinkers, light drinkers who avoided wine, had a relative risk of death from all causes of 0.90 (0.82-0.99) and those who drank wine had a relative risk of 0.66 (0.55-0.77). Heavy drinkers who avoided wine were at higher risk of death from all causes than were heavy drinkers who included wine in their alcohol intake. Wine drinkers had significantly lower mortality from both coronary heart disease and cancer than did non-wine drinkers (p = 0.007 and p = 0.004, respectively). In conclusion, wine intake may have a beneficial effect on all cause mortality that is additive to that of alcohol. This effect may be attributable to a reduction in death from both coronary heart disease and cancer.

Alcohol Drinking↗
PubMed2001

Dynamic simulation of electromechanical systems: from Maxwell's theory to common-rail diesel injection.

This paper describes the state-of-the-art of dynamic simulation of electromechanical systems. Electromechanical systems can be split into electromagnetic and mechanical subsystems, which are described by Maxwell's equations and by Newton's law, respectively. Since such systems contain moving parts, the concepts of Lorentz and Galilean relativity are briefly addressed. The laws of physics are formulated in terms of (partial) differential equations. Numerical methods ultimately aim at linear systems of equations, which can be solved efficiently on digital computers. The various discretization methods for performing this task are discussed. Special emphasis is placed on domain decomposition as a framework for the coupling of different numerical methods such as the finite element method and the boundary element method. The paper concludes with descriptions of some applications of industrial relevance: a high performance injection valve and an electromechanical relay.

Journal Article↗
PubMed2001

A comparison of circulating and regional growth hormone-binding protein in cirrhosis.

The growth hormone (GH)/insulin-like growth factor-I (IGF-I) axis is disturbed in cirrhosis, with elevated basal GH and low IGF-I levels relating to liver function and prognosis. In plasma, GH is bound to a high-affinity GH-binding protein (GHBP), which has been found to be slightly reduced in cirrhosis, but with huge variations. GHBP is identical to the extracellular part of the hepatic GH receptor, but other tissues may contribute to the circulating GHBP levels. The aim was therefore to measure circulating and regional concentrations of GHBP in relationship to hepatic function and body composition in patients with cirrhosis (n = 38) and controls with normal liver function (n = 29). Blood samples from the hepatic, renal, and femoral veins and the femoral artery were collected simultaneously during a hemodynamic investigation. Plasma GHBP was directly measured by a specific and sensitive fluoroimmunoassay. Circulating GHBP levels were identical in the patients and controls (mean +/- SD) 1.03 +/- 0.56 nmol/L and 1.02 +/- 0.55 nmol/L, respectively (not significant). We found no significant hepatic, renal, or peripheral arteriovenous extractions or generations of GHBP, and it did not significantly correlate to liver function. In the controls, GHBP correlated significantly with body mass index (BMI) (r =.60, P <.005), whereas this relationship was not found in the patients with cirrhosis. In conclusion, high-affinity GHBP appears to be normal in patients with cirrhosis, with no significant hepatic generation or renal extraction and no association with the severity of the liver disease. Thus, our study supports the hypothesis that tissues other than the liver, despite its abundant GH receptors, may contribute to the circulating GHBP.

Aged↗
PubMed2001

Endoscopic Doppler ultrasound for measurement of azygos blood flow. Validation against thermodilution and assessment of pharmacological effects of terlipressin in portal hypertension.

BACKGROUND: Endoscopic ultrasound (EUS) is a new modality allowing real-time flow measurements by means of the Doppler technique. The aim of the study was to evaluate azygos blood flow measurements by endoscopic ultrasound. METHODS: Measurements of azygos blood flow by EUS and by the thermodilution technique were compared in 20 patients with portal hypertension. The ability of EUS flowmetry to detect changes in the azygos and portal venous flow after an intravenous dose of 2 mg of terlipressin was evaluated in 13 of the patients in a double-blind, randomized, placebo-controlled, cross-over design. RESULTS: The EUS Doppler and thermodilution measurements correlated significantly (R=0.81, P < 0.001). The azygos blood flow was found to be 14% higher by the EUS method than by thermodilution. The coefficient of variation of the EUS Doppler measurements of the azygos blood flow was 14.8%. After administration of terlipressin, the azygos blood flow, as measured by EUS Doppler, decreased significantly by 23% from 915 to 704 ml/min (P = 0.014) and the portal venous flow decreased by 28% from 1170 to 789 ml/min (P = 0.03). No effects of placebo were detected. CONCLUSIONS: These results show that EUS measurement of the azygos blood flow correlate strongly to the measurements by the thermodilution technique, and EUS is moreover well tolerated by the patients. The method is applicable for monitoring pharmacological effects on the superior porto-systemic collateral circulation and portal venous flow in patients with portal hypertension.

Adult↗
PubMed2001

High arterial compliance in cirrhosis is related to low adrenaline and elevated circulating calcitonin gene related peptide but not to activated vasoconstrictor systems.

BACKGROUND AND AIMS: Static and dynamic functions of the wall of large arteries are largely unknown in cirrhosis in vivo. The present study was undertaken to determine arterial compliance (COMP(art)) in relation to vasodilator and vasoconstrictor systems in patients with cirrhosis. In addition, vasoactivity was manipulated by inhalation of oxygen. STUDY POPULATION AND METHODS: In 20 patients with alcoholic cirrhosis and 12 controls we determined COMP(art) (stroke volume relative to pulse pressure), cardiac output, plasma volume, systemic vascular resistance, central circulation time, plasma catecholamines, renin activity, endothelin-1, and calcitonin gene related peptide (CGRP) at baseline and during oxygen inhalation. RESULTS: COMP(art) was significantly increased in cirrhotic patients compared with controls (1.32 v 1.06 ml/mm Hg; p< 0.05) and inversely related to plasma adrenaline levels (r=-0.53; p<0.02) but positively related to circulating levels of CGRP (r=0.58; p<0.01). No significant relation was found for plasma noradrenaline, renin activity, or endothelin-1. COMP(art) was positively related to plasma volume (r=0.50; p<0.02) and inversely to systemic vascular resistance (r=-0.69; p<0.001) and central circulation time (r=-0.49; p<0.02). During oxygen inhalation, COMP(art) decreased (-13%; p<0.005) and systemic vascular resistance increased (+10%; p<0.001) towards normal values without significant changes in mean arterial pressure. Plasma adrenaline (-16%; p<0.01) decreased and the relation to COMP(art) disappeared. The relation of COMP(art) to CGRP and circulatory variables remained unchanged. CONCLUSION: Elevated arterial compliance in cirrhosis is related to low adrenaline, high CGRP, and systemic hyperdynamics but not to indicators of the activated vasoconstrictor systems (noradrenaline, renin, endothelin-1). Thus the altered static and dynamic characteristics of the wall of large arteries are intimately associated with circulatory and vasodilatory derangement in cirrhosis but biomanipulation indicates that the changes are, at least in part, reversible during isobaric conditions.

Adult↗
PubMed2000

Sudden interchannel interaction in the Tl 6p ionization above the 5d threshold

The linear magnetic dichroism in the angular distribution of Tl 5d and 6p photoelectrons and their dynamical spin polarization have been measured between hnu = 30 and 50 eV. In contrast to the Xe 5p photoionization at the 4d threshold, our results show that above the Tl 5d threshold strong interchannel coupling effects induce a sudden increase in the asymptotic phase difference of the s and d waves for the Tl 6p ionization. This shows that the valence excitation is different for resonant (Xe 4d) and nonresonant (Tl 5d) excitation from subvalence shells.

Journal Article↗
PubMed2000

Type of alcohol consumed and mortality from all causes, coronary heart disease, and cancer.

BACKGROUND: Although the J-shaped relation between alcohol intake and mortality has been reproduced in many large cohort studies, the question of whether the effects of beer, wine, and spirits differ remains controversial. OBJECTIVE: To examine the relation between intake of different types of alcohol and death from all causes, coronary heart disease, and cancer. DESIGN: Pooled cohort studies in which intake of beer, wine, and spirits; smoking status; educational level; physical activity; and body mass index were assessed at baseline. SETTING: Copenhagen, Denmark. PARTICIPANTS: 13 064 men and 11 459 women 20 to 98 years of age. MEASUREMENTS: Number of deaths and time to death from all causes, coronary heart disease, and cancer during follow-up. RESULTS: During 257 859 person-years of follow-up, 4833 participants died. J-shaped relations were found between total alcohol intake and mortality at various levels of wine intake. Compared with nondrinkers, light drinkers who avoided wine had a relative risk for death from all causes of 0.90 (95% CI, 0.82 to 0.99) and those who drank wine had a relative risk of 0.66 (CI, 0. 55 to 0.77). Heavy drinkers who avoided wine were at higher risk for death from all causes than were heavy drinkers who included wine in their alcohol intake. Wine drinkers had significantly lower mortality from both coronary heart disease and cancer than did non-wine drinkers (P = 0.007 and P = 0.004, respectively). CONCLUSION: Wine intake may have a beneficial effect on all-cause mortality that is additive to that of alcohol. This effect may be attributable to a reduction in death from both coronary heart disease and cancer.

Adult↗
PubMed2000

The acid-labile subunit of the ternary insulin-like growth factor complex in cirrhosis: relation to liver dysfunction.

BACKGROUND/AIMS: In the circulation, insulin-like growth factor-I (IGF-I) is bound in a trimeric complex of 150 kDa with IGF binding protein-3 (IGFBP-3) and the acid-labile subunit (ALS). Whereas circulating IGF-I and IGFBP-3 are reported to be low in patients with chronic liver failure, the level of ALS has not been described in relation to hepatic dysfunction. The aim of the present study was therefore to measure circulating and hepatic venous concentrations of ALS in relation to hepatic function and the IGF axis. METHODS: Twenty-five patients with cirrhosis (Child class A/B/C:5/10/10) and 30 controls with normal liver function were studied. During a haemodynamic investigation, blood samples were collected from the hepatic vein and femoral artery, and the plasma concentrations of ALS, IGF-I and IGFBP-3 were determined. RESULTS: Hepatic venous and arterial concentrations of ALS were significantly decreased in the cirrhotic patients compared with the controls (-69% and -68%, respectively, both p<0.001). IGF-I and IGFBP-3 were similarly decreased in the cirrhotic patients (-51%,p<0.001). A significant hepatic extraction of ALS was found in the controls (6%, p<0.01) and in the cirrhotic patients (8%, p=0.08). ALS correlated significantly with indicators of liver dysfunction, including the Child-Turcotte score (r=-0.69, p<0.0001), IGF-I (r=0.82, p<0.0001) and IGFBP-3 (r=0.74, p<0.0001). CONCLUSIONS: Circulating and hepatic venous ALS are decreased in patients with cirrhosis with significant relations to liver dysfunction and other components of the IGF complex. A small hepatic extraction was found in controls, which suggests extrahepatic production of ALS. Future studies should focus on organ-specific removal of ALS.

Adult↗
PubMed2000

Central and systemic haemodynamic effects of terlipressin in portal hypertensive patients.

AIMS/BACKGROUND: Cirrhotic patients exhibit a hyperdynamic and hyporeactive circulation with central hypovolaemia which may influence the course of the disease. As terlipressin, a vasopressin analogue, may modify systemic haemodynamics in these patients, the aim of the present study was to assess the acute effects of terlipressin on central and systemic haemodynamics. METHODS: Sixteen patients with alcoholic cirrhosis and portal hypertension had their systemic, central, and splanchnic haemodynamics determined at baseline and after a blind randomised bolus infusion (2 mg) of terlipressin/placebo. RESULTS: After terlipressin, the arterial blood pressure and the systemic vascular resistance increased by 26% and 61%, respectively (both p<0.001), and the cardiac output, heart rate, and arterial compliance decreased by 18%, 11%, and 32%, respectively (all p<0.001). The central circulation time increased by 36% (p<0.001), whereas the central and arterial blood volume only increased by 4% (p= 0.07). As expected, both portal pressure and hepatic blood flow decreased (17% and 29%, both p<0.001). The decrease in portal pressure after terlipressin was significantly related to the increase in systemic vascular resistance (r=-0.52, p<0.05) and the central circulation time (r=-0.80, p<0.0001). CONCLUSIONS: Terlipressin significantly attenuates the hyperdynamic circulation in portal hypertensive patients without a further contraction of the central and arterial blood volume. The systemic haemodynamic response to terlipressin is moreover associated with the decrease in portal pressure. Terlipressin may therefore have potentially beneficial effects on the hyperdynamic circulation in cirrhosis in addition to its effects on portal pressure.

Adult↗
PubMed1999

Alcohol intake and the risk of lung cancer: influence of type of alcoholic beverage.

Alcohol consumption has been associated with an increased risk of lung cancer, but the antioxidants in wine may, in theory, provide protection. This association was studied in 28,160 men and women subjects from three prospective studies conducted in 1964-1992 in Copenhagen, Denmark. After adjustment for age, smoking, and education, a low to moderate alcohol intake (1-20 drinks per week) was not associated with an increased risk of lung cancer. Men who consumed 21-41 and more than 41 drinks per week had relative risks of 1.23 (95% confidence interval (CI) 0.88-1.74) and 1.57 (95% CI 1.06-2.33), respectively. The risk of lung cancer differed according to the type of alcohol consumed: After abstainers were excluded, drinkers of 1-13 and more than 13 glasses of wine per week had relative risks of 0.78 (95% CI 0.63-0.97) and 0.44 (95% CI 0.22-0.86), respectively, as compared with nondrinkers of wine (p for trend = 0.002). Corresponding relative risks for beer intake were 1.09 (95% CI 0.83-1.43) and 1.36 (95% CI 1.02-1.82), respectively (p for trend = 0.01); for spirits, they were 1.21 (95% CI 0.97-1.50) and 1.46 (95% CI 0.99-2.14), respectively (p for trend = 0.02). In women, the ability to detect associations with high alcohol intake and type of beverage was limited because of a limited range of alcohol intake. The authors concluded that in men, a high consumption of beer and spirits is associated with an increased risk of lung cancer, whereas wine intake may protect against the development of lung cancer.

Adult↗
PubMed1999

Splanchnic haemodynamics after intravenous terlipressin in anaesthetised healthy pigs.

BACKGROUND/AIMS: Terlipressin is used for the treatment of bleeding oesophageal varices. We evaluated the effects of terlipressin on hepatic haemodynamics, with special focus on the interactions between portal venous flow and hepatic arterial flow over time. Secondly, we evaluated the estimated hepatic blood flow by the ICG clearance method against direct measurements of hepatic blood flow. METHODS: Eight healthy anaesthetised pigs received terlipressin 1 mg or placebo intravenously in a randomised, blind, cross-over design. Hepatic arterial flow, portal venous flow, systemic haemodynamics, and portal vein diameter were recorded simultaneously. Portal venous flow and hepatic arterial flow were measured by transit time ultrasound flowmetry. Estimated hepatic blood flows at baseline and after terlipressin were compared with the sum of the portal venous flow and hepatic arterial flow. RESULTS: Portal venous flow decreased significantly 5 min after administration of terlipressin (p<0.05). At 30 min it had decreased by 34% (p<0.01) and the hepatic arterial flow had increased by 81% (p<0.01). The estimated hepatic blood flow and the hepatic blood flow decreased by 23% (p<0.015). At baseline the estimated hepatic blood flow and the hepatic blood flow correlated significantly (r=0.85, p<0.01), but this correlation disappeared after administration of terlipressin (r=0.06, p=ns). The hepatic blood flow was 12% higher than the estimated hepatic blood flow before and after terlipressin. CONCLUSIONS: Terlipressin decreased the portal venous flow, hepatic blood flow, and estimated hepatic blood flow significantly and was accompanied by a substantial increase in hepatic arterial flow. The estimated hepatic blood flow and hepatic blood flow were strongly correlated at baseline, but after terlipressin the correlation disappeared.

Anesthesia↗
PubMed1999

Endoscopic ultrasound duplex scanning for measurement of portal venous flow. Validation against transit time ultrasound flowmetry in pigs.

BACKGROUND: Endoscopic ultrasound (EUS) is a new technique that makes it possible to measure portal venous flow when transabdominal ultrasound fails. As the technique has not been evaluated previously, we compared simultaneous measurements of portal venous flow using EUS Doppler with that of transit time ultrasound (TTU) in healthy pigs. The ability of EUS to detect changes in the portal venous flow after pharmacologic intervention was also investigated. METHODS: Six anaesthetized pigs were studied. Portal venous flow was measured simultaneously by EUS duplex scanning, using a Pentax FG-32UA echoendoscope connected to a Hitachi EUB 515-A ultrasound scanner, and by TTU with a Cardiomed CM 4000 flowmeter probe placed on the portal vein. Terlipressin, 1 mg, and placebo were administered in a blind, randomized, crossover design. Measurements were taken at base line and 30 min after each drug administration. RESULTS: Portal venous flow measured by EUS flowmetry and TTU flowmetry correlated significantly (R = 0.92, P < 0.001, n = 18). The limits of agreement in a Bland-Altman plot were from -0.262 l/min to +0.164 l/min. The change in portal venous flow after terlipressin measured by EUS and TTU correlated significantly (R = 0.88, P < 0.05, n = 6). All values used for analyses were the means of five repeated measurements. CONCLUSIONS: EUS measures portal venous flow with an acceptable correlation and agreement with TTU in anaesthetized pigs. The method is capable of monitoring the effects of pharmacologic intervention on the portal system.

Animals↗
PubMed1999

Beer, wine, spirits and subjective health.

STUDY OBJECTIVE: To examine the association between intake of different types of alcoholic beverages and self reported subjective health. DESIGN: Cross sectional health survey with assessment of intake of beer, wine and spirits (at last non-weekend day), smoking habits, social networks, physical activity, body mass index, educational level, presence of chronic disease, and self reported health. SETTING: WHO Copenhagen Healthy City Survey, Denmark. PARTICIPANTS: 4113 men and 7926 women aged 18 to 100 years. MAIN RESULTS: Of the 12,039 subjects, 8680 reported their health as optimal, and 3359 reported a suboptimal health. After controlling for the covariates, the relation between total alcohol intake and the proportion reporting suboptimal health was J shaped. Heavy drinkers of any of the three types of alcoholic beverages had a higher prevalence of suboptimal health than non-drinkers. However, only light (1-2 glasses of wine yesterday) and moderate (3-5) wine drinkers had significantly lower odds ratios for suboptimal health--0.72 (95% confidence limits; 0.56 to 0.92) and 0.65 (0.49 to 0.87), respectively--when compared with non-wine drinkers. Moderate beer or spirits drinkers did not differ significantly from non-drinkers of these beverages with regard to prevalence of suboptimal health. Consistently, beer preference drinkers had an odds ratio of 1.50 (1.25 to 1.80) for suboptimal health compared with wine preference drinkers. CONCLUSIONS: A light to moderate wine intake is related to good self perceived health, whereas this is not the case for beer and spirits. The causal relations creating this association are unknown and should be considered when interpreting the relation between different types of alcoholic beverages and subsequent morbidity and mortality.

Adolescent↗