43 research outputs found
Response to letter by Pilz et al
Copyright: Copyright 2008 Elsevier B.V., All rights reserved.publishersversionPeer reviewe
The Serifos Metamorphic Core Complex (Greece) — kinematic investigations of the southern detachment mylonites
The island of Serifos is situated about
100km SSE of Athens in the Aegean
Sea and belongs to the Attic-Cycladic
massif. The geology of Serifos is largely
characterized by a shallow hornblendebiotite
granodiorite pluton that intruded
in the late Miocene into a previously
deformed (under blueschist conditions)
sequence mainly consisting of
ortho- and paragneisses, calc-silicate
marbles, amphibolites and schists. The
pluton has a dome-shaped body occupying
the central and southern parts of
the island (Salemink 1985). The Serifos
MCC is the very western continuation of a zone of syn- to post tectonic intrusions
younging from the East (Naxos,
Paros ?12Ma) to the West (Serifos 9–
8Ma). Whereas the older intrusions in
the East show a top to the North geometry,
the Serifos MCC has developed
a South-directed low-angle detachment
fault...conferenc
Kinematics and deformation structures in a crustal-scale shear zone on Kea (W. Cyclades, Greece)
It is generally agreed upon that the exhumation
of metamorphic rocks in the
Aegean is caused by post orogenic extension
in the late Oligocene to early
Miocene. This extension is in principle
largely accommodated by low-angle
crustal detachment faulting possibly resulting
in the formation of metamorphic
core complexes (MCC).
Here, we present data from recent structural
investigations on the island of Kea
in the W. Cyclades, Greece. Our work
focussed in the north of the island. Of
the ca. 270m total structural thickness
that was mapped, the entire section
of rocks are highly strained. Exhumation
during progressive deformation is
recorded by the transition from ductile
to brittle/ductile to brittle conditions.
The regional characteristics and types
of deformation structures vary depending
on the protolith and the intensity of
strain...conferenc
Sequencing patterns of ventilatory indices in less trained adults
Submaximal ventilatory indices, i.e., point of optimal ventilatory efficiency (POE) and anaerobic threshold (AT), are valuable indicators to assess the metabolic and ventilatory response during cardiopulmonary exercise testing (CPET). The order in which the ventilatory indices occur (ventilatory indices sequencing pattern, VISP), may yield additional information for the interpretation of CPET results and for exercise intensity prescription. Therefore, we determined whether different VISP groups concerning POE and AT exist. Additionally, we analysed fat metabolism via the exercise intensity eliciting the highest fat oxidation rate (Fatmax) as a possible explanation for differences between VISP groups. 761 less trained adults (41–68 years) completed an incremental exercise test on a cycle ergometer until volitional exhaustion. The ventilatory indices were determined using automatic and visual detection methods, and Fatmax was determined using indirect calorimetry. Our study identified two VISP groups with a lower work rate at POE compared to AT in VISPPOE < AT but not in group VISPPOE = AT. Therefore, training prescription based on POE rather than AT would result in different exercise intensity recommendations in 66% of the study participants and consequently in unintended physiological adaptions. VISPPOE < AT participants were not different to VISPPOE = AT participants concerning VO2peak and Fatmax. However, participants exhibiting a difference in work rate (VISPPOE < AT) were characterized by a higher aerobic capacity at submaximal work rate compared to VISPPOE = AT. Thus, analysing VISP may help to gain new insights into the complex ventilatory and metabolic response to exercise. But a methodological framework still must be established
Extensional crustal-scale shear zones in the Western Cyclades (Kea, Greece)
Intense seismicity and intensely developed
active and ancient fault systems
are common to the Aegean Region. Extending/
thinning crust involves a complex
interplay of (1) Gulf of Corinth riftexpansion,
(2) west- and south-ward retreat
of the Hellenic Trench, (3) westward
impingement of the Anatolian
Platen, and/or (4) propagation of the
Anatolian Fault system into the Aegean.
New geological/structural investigations
on Kea (also known as Tzia), in
the Western Cyclades reveal a low angle
crustal-scale, detachment-type ductile
shear zone probably formed during
Miocene extension and thinning of the
continental crust...conferenc
The Mitochondrial T16189C Polymorphism Is Associated with Coronary Artery Disease in Middle European Populations
BACKGROUND: The pivotal role of mitochondria in energy production and free radical generation suggests that the mitochondrial genome could have an important influence on the expression of multifactorial age related diseases. Substitution of T to C at nucleotide position 16189 in the hypervariable D-loop of the control region (CR) of mitochondrial DNA (mtDNA) has attracted research interest because of its suspected association with various multifactorial diseases. The aim of the present study was to compare the frequency of this polymorphism in the CR of mtDNA in patients with coronary artery disease (CAD, n = 482) and type 2 diabetes mellitus (T2DM, n = 505) from two study centers, with healthy individuals (n = 1481) of Middle European descent in Austria. METHODOLOGY AND PRINCIPAL FINDINGS: CR polymorphisms and the nine major European haplogroups were identified by DNA sequencing and primer extension analysis, respectively. Frequencies and Odds Ratios for the association between cases and controls were calculated. Compared to healthy controls, the prevalence of T16189C was significantly higher in patients with CAD (11.8% vs 21.6%), as well as in patients with T2DM (11.8% vs 19.4%). The association of CAD, but not the one of T2DM, with T16189C remained highly significant after correction for age, sex and body mass index (BMI) and was independent of the two study centers. CONCLUSIONS AND SIGNIFICANCE: Our results show for the first time a significant association of T16189C with CAD in a Middle European population. As reported in other studies, in patients with T2DM an association with T16189C in individuals of European decent remains questionable
Mitochondrial DNA haplogroup T is associated with coronary artery disease and diabetic retinopathy: a case control study
<p>Abstract</p> <p>Background</p> <p>There is strong and consistent evidence that oxidative stress is crucially involved in the development of atherosclerotic vascular disease. Overproduction of reactive oxygen species (ROS) in mitochondria is an unifying mechanism that underlies micro- and macrovascular atherosclerotic disease. Given the central role of mitochondria in energy and ROS production, mitochondrial DNA (mtDNA) is an obvious candidate for genetic susceptibility studies on atherosclerotic processes. We therefore examined the association between mtDNA haplogroups and coronary artery disease (CAD) as well as diabetic retinopathy.</p> <p>Methods</p> <p>This study of Middle European Caucasians included patients with angiographically documented CAD (n = 487), subjects with type 2 diabetes mellitus with (n = 149) or without (n = 78) diabetic retinopathy and control subjects without clinical manifestations of atherosclerotic disease (n = 1527). MtDNA haplotyping was performed using multiplex PCR and subsequent multiplex primer extension analysis for determination of the major European haplogroups. Haplogroup frequencies of patients were compared to those of control subjects without clinical manifestations of atherosclerotic disease.</p> <p>Results</p> <p>Haplogroup T was significantly more prevalent among patients with CAD than among control subjects (14.8% vs 8.3%; p = 0.002). In patients with type 2 diabetes, the presence of diabetic retinopathy was also significantly associated with a higher prevalence of haplogroup T (12.1% vs 5.1%; p = 0.046).</p> <p>Conclusion</p> <p>Our data indicate that the mtDNA haplogroup T is associated with CAD and diabetic retinopathy in Middle European Caucasian populations.</p
Predictive value for cardiovascular events of common carotid intima media thickness and its rate of change in individuals at high cardiovascular risk - Results from the PROG-IMT collaboration.
AIMS: Carotid intima media thickness (CIMT) predicts cardiovascular (CVD) events, but the predictive value of CIMT change is debated. We assessed the relation between CIMT change and events in individuals at high cardiovascular risk. METHODS AND RESULTS: From 31 cohorts with two CIMT scans (total n = 89070) on average 3.6 years apart and clinical follow-up, subcohorts were drawn: (A) individuals with at least 3 cardiovascular risk factors without previous CVD events, (B) individuals with carotid plaques without previous CVD events, and (C) individuals with previous CVD events. Cox regression models were fit to estimate the hazard ratio (HR) of the combined endpoint (myocardial infarction, stroke or vascular death) per standard deviation (SD) of CIMT change, adjusted for CVD risk factors. These HRs were pooled across studies. In groups A, B and C we observed 3483, 2845 and 1165 endpoint events, respectively. Average common CIMT was 0.79mm (SD 0.16mm), and annual common CIMT change was 0.01mm (SD 0.07mm), both in group A. The pooled HR per SD of annual common CIMT change (0.02 to 0.43mm) was 0.99 (95% confidence interval: 0.95-1.02) in group A, 0.98 (0.93-1.04) in group B, and 0.95 (0.89-1.04) in group C. The HR per SD of common CIMT (average of the first and the second CIMT scan, 0.09 to 0.75mm) was 1.15 (1.07-1.23) in group A, 1.13 (1.05-1.22) in group B, and 1.12 (1.05-1.20) in group C. CONCLUSIONS: We confirm that common CIMT is associated with future CVD events in individuals at high risk. CIMT change does not relate to future event risk in high-risk individuals
Automatic identification of variables in epidemiological datasets using logic regression
textabstractBackground: For an individual participant data (IPD) meta-analysis, multiple datasets must be transformed in a consistent format, e.g. using uniform variable names. When large numbers of datasets have to be processed, this can be a time-consuming and error-prone task. Automated or semi-automated identification of variables can help to reduce the workload and improve the data quality. For semi-automation high sensitivity in the recognition of matching variables is particularly important, because it allows creating software which for a target variable presents a choice of source variables, from which a user can choose the matching one, with only low risk of having missed a correct source variable. Methods: For each variable in a set of target variables, a number of simple rules were manually created. With logic regression, an optimal Boolean combination of these rules was searched for every target variable, using a random subset of a large database of epidemiological and clinical cohort data (construction subset). In a second subset of this database (validation subset), this optimal combination rules were validated. Results: In the construction sample, 41 target variables were allocated on average with a positive predictive value (PPV) of 34%, and a negative predictive value (NPV) of 95%. In the validation sample, PPV was 33%, whereas NPV remained at 94%. In the construction sample, PPV was 50% or less in 63% of all variables, in the validation sample in 71% of all variables. Conclusions: We demonstrated that the application of logic regression in a complex data management task in large epidemiological IPD meta-analyses is feasible. However, the performance of the algorithm is poor, which may require backup strategies