Showing papers by "University of Jena published in 2001"

The Unified Neutral Theory of Biodiversity and Biogeography

Abstract: study of the issue indicates that it is not a serious problem for neutral theory, for reasons we discuss below. First, a bit of background. Hubbell (2001) derived the analytical expression for the stochastic mean and variance of the abundance of a single arbitrary species in a neutral community undergoing immigration from a metacommunity source area. However, his approach did not lend itself to an analytical solution for the distribution of relative species abundance (RSA) in a multispecies community for community sizes larger than a handful of individuals. As a result, all of Hubbell's RSA distributions for local communities were based on simulations. This problem was solved by Volkov et al. (2003), who derived an analytical expression for the RSA distribution in local communities of arbitrary size. However, as Chisholm and Burgman noted, there is sometimes a difference between some of the simulation-based results of Hubbell and the analytical results of Volkov et al. (2003). Chisholm and Burgman computed Volkov's equation and resimulated Hubbell's results for the four cases

Perzentile für den Body-mass-Index für das Kindes- und Jugendalter unter Heranziehung verschiedener deutscher Stichproben

Abstract: Fragestellung. Sowohl die Childhood Group der International Obesity Task Force (IOTF) als auch die European Childhood Obesity Group (ECOG) empfehlen den Body-mass-Index als Beurteilungskriterium fur Ubergewicht und Adipositas bei Kindern und Jugendlichen. Im Erwachsenenalter erfolgt die Definition von Ubergewicht und Adipositas anhand fester Grenzwerte, bei der Beurteilung von Kindern und Jugendlichen mussen die alters- und geschlechtsspezifischen Veranderungen des BMI berucksichtigt werden. Methode. Unter Heranziehung von 17 bereits durchgefuhrten Untersuchungen aus verschiedenen Regionen Deutschlands wurden BMI-Perzentile fur Kinder und Jugendliche erstellt. Die Berechnung der Perzentile basiert auf den Korperhohen- und Korpergewichtsdaten von 17.147 Jungen und 17.275 Madchen im Alter von 0–18 Jahren. Ergebnisse und Schlussfolgerung. Die vorgestellten Perzentile sollten als Referenz fur deutsche Kinder und Jugendliche angewendet werden. Die Arbeitsgemeinschaft “Adipositas im Kindes- und Jugendalter” (AGA) hat in ihren Leitlinien die Anwendung der hier vorgestellten 90. und 97. Perzentile zur Definition von Ubergewicht und Adipositas empfohlen.

Influences on Loneliness in Older Adults: A Meta-Analysis

Abstract: A widely held stereotype associates old age with social isolation and loneliness. However, only 5% to 15% percent of older adults report frequent loneliness. In this study, we report a meta-analysis of the correlates of loneliness in late adulthood. A U-shaped association between age and loneliness is identified. Quality of social network is correlated more strongly with loneliness, compared to quantity; contacts with friends and neighbors show stronger associations with loneliness, compared to contacts with family members. Being a woman, having low socioeconomic status and low competence, and living in nursing homes were also associated with higher loneliness. Age differences in the association of social contacts and competence with loneliness are investigated as well.

Fungal laccase: properties and activity on lignin

Abstract: (Received 17 October 2000/Accepted 12 April 2001) The sources of ligninocellulose that occur in various forms in nature are so vast that they can only be compared to those of water. The results of several, more recent experiments showed that laccase probably possesses the big ability for "lignin-barrier" breakdown of ligninocellulose. The degradation of this compound is currently understood as an enzymatic process mediated by small molecules, therefore, this review will focus on the role of these mediators and radicals working in concert with enzymes. The fungi having a versatile machinery of enzymes are able to attack directly the "lignin- barrier" or can use a multienzyme system including "feed-back" type enzymes allowing for simulta- neous transformation of lignin and carbohydrate compounds.

The Optimal Migration Duration and Activity Choice after Re-Migration

Abstract: If migrants return to their origin countries, two questions arise which are of immediate economic interest for both immigration and emigration country: What determines their optimal migration duration, and what are the activities migrants choose after a return. Little research has been devoted to these two issues. This paper utilizes a unique survey data set which records activities of returned migrants. We first illustrate the activities of immigrants after returning. We show that more than half of the returning migrants are economically active after return, and most of them engage in entrepreneurial activities. We then develop a model, where migrants decide simultaneously about the optimal migration duration, and their after-return activities. Guided by this model, we specify and estimate an empirical model, where the after-return activity, and the optimal migration duration are simultaneously chosen.

Gender Differences in Self-Concept and Psychological Well-Being in Old Age A Meta-Analysis

Abstract: Because of women's higher risk of being widowed, having health problems, and needing care, one might expect them to have a more negative self-concept and lower subjective well-being (SWB). However, women may also have greater access to sources of SWB (e.g., relations to adult children) and may engage in processes to protect the self (e.g., lowered aspirations). Meta-analysis was used to synthesize findings from 300 empirical studies on gender differences in life satisfaction, happiness, self-esteem, loneliness, subjective health, and subjective age in late adulthood. Older women reported significantly lower SWB and less positive self-concept than men on all measures, except subjective age, although gender accounted for less than 1% of the variance in well-being and self-concept. Smaller gender differences in SWB were found in younger than in older groups. Statistically controlling for gender differences in widowhood, health, and socioeconomic status decreased gender differences in SWB. Cohort differences in SWB are reported as well.

Nationalism and patriotism: National identification and out‐group rejection

Abstract: It is argued that the differentiation between nationalism and patriotism proposed in the literature can be seen as analogous to judgments based on different types of comparisons: intergroup comparisons with other nations are associated with intergroup behaviour that corresponds to nationalism, whereas temporal or standard comparisons are linked with behaviour that corresponds to patriotism. Four studies (N = 103, 107, 96 and 105) conducted in Germany and Britain examined the hypothesis that national identification and in-group evaluation only show a reliable relationship with out-group rejection under an intergroup comparison orientation. Participants were primed with either an intergroup comparison, a temporal comparison or no explicit comparison orientation. A subsequent questionnaire assessed in-group (own country) identification, in-group evaluation (i.e. national pride) and rejection of national out-groups. Across all four studies, both in-group identification and in-group evaluation show a stronger correlation with out-group derogation if participants were primed with an intergroup comparison orientation compared to temporal and control conditions. Results are discussed with regard to nationalism and patriotism as well as Hinkle and Brown's (1990) model on relational vs. autonomous orientations.

Ultrastructure of attachment specializations of hexapods (Arthropoda): evolutionary patterns inferred from a revised ordinal phylogeny

Abstract: Attachment devices of representatives of most higher taxa of hexapods were examined. Short descriptions of tibial, tarsal and pretarsal adhesive structures for each order are presented. In their evolution, hexapods have developed two distinctly different mechanisms to attach themselves to a variety of substrates: hairy surfaces and smooth flexible pads. The flexible properties of pad material guarantees a maximal contact with surfaces, regardless of the microsculpture. These highly specialized structures are not restricted to one particular area of the leg. They may be located on different parts, such as claws, derivatives of the pretarsus, tarsal apex, tarsomeres, or tibia. The 10 characters of the two alternative designs of attachment devices – smooth and hairy – were coded and analysed together with a data matrix containing 105 additional morphological characters of different stages and body parts. The analysis demonstrates, that similar structures (arolium, euplantulae, hairy tarsomeres) have evolved independently in several lineages. Nevertheless, some of them support monophyletic groups (e.g. Embioptera + Dermaptera; Dictyoptera + Phasmatodea + Grylloblattodea + Orthoptera; Dictyoptera + Phasmatodea; Hymenoptera + Mecopterida; Neuropterida + Strepsiptera + Coleoptera). Other structures such as claw pads (Ephemeroptera), balloon-shaped eversible pads (Thysanoptera), or fossulae spongiosae (Reduviidae) are unique for larger or smaller monophyletic units. It is plausible to assume that the evolution of flight and the correlated necessity to cling to vegetation or other substrates was a major trigger for the evolution of adhesive structures. Groups with a potential to evolve a great variety of designs of adhesive pads are Hemiptera and Diptera. Even though characters of the adhesive pads are strongly subject to selection, they can provide phylogenetic information. The results of the cladistic analyses are largely congruent with current hypotheses of hexapod phylogeny. A sistergroup relationship between Diplura and Insecta and between Zygentoma (excl. Tricholepidion) and Pterygota is confirmed. Plecoptera are probably the sistergroup of the remaining Neoptera. Dermaptera are the sistergroup of Embioptera and Dictyoptera the sistergroup of Phasmatodea. Paurometabola excl. Dermaptera + Embioptera are monophyletic. A sistergroup relationship between Zoraptera and a clade comprising Paraneoptera + Endopterygota is only supported by weak evidence. Coleoptera + Strepsiptera are the sistergroup of Neuropterida and Hymenoptera the sistergroup of Mecopterida.

Regulation of cell function by methionine oxidation and reduction

Abstract: Reactive oxygen species (ROS) are generated during normal cellular activity and may exist in excess in some pathophysiological conditions, such as inflammation or reperfusion injury. These molecules oxidize a variety of cellular constituents, but sulfur-containing amino acid residues are especially susceptible. While reversible cysteine oxidation and reduction is part of well-established signalling systems, the oxidation and the enzymatically catalysed reduction of methionine is just emerging as a novel molecular mechanism for cellular regulation. Here we discuss how the oxidation of methionine to methionine sulfoxide in signalling proteins such as ion channels affects the function of these target proteins. Methionine sulfoxide reductase, which reduces methionine sulfoxide to methionine in a thioredoxin-dependent manner, is therefore not only an enzyme important for the repair of age- or degenerative disease-related protein modifications. It is also a potential missing link in the post-translational modification cycle involved in the specific oxidation and reduction of methionine residues in cellular signalling proteins, which may give rise to activity-dependent plastic changes in cellular excitability.

Involuntary Motor Activity in Pianists Evoked by Music Perception

Abstract: Pianists often report that pure listening to a well-trained piece of music can involuntarily trigger the respective finger movements We designed a magnetoencephalography (MEG) experiment to compare the motor activation in pianists and nonpianists while listening to piano pieces For pianists, we found a statistically significant increase of activity above the region of the contralateral motor cortex Brain surface current density (BSCD) reconstructions revealed a spatial dissociation of this activity between notes preferably played by the thumb and the little finger according to the motor homunculus Hence, we could demonstrate that pianists, when listening to well-trained piano music, exhibit involuntary motor activity involving the contralateral primary motor cortex (M1)

Correlates of subjective health in older adults: a meta-analysis.

Abstract: Age-associated changes of subjective health and associations of subjective health with physical health, functional health, and mental health were meta-analyzed in older adults (M age > 60 years). An age-associated decline of subjective health, which was stronger in old-old samples than in young-old samples, was found. Subjective health was correlated with the indicators of objective health, but the association with physical health was stronger than with functional health. Correlations of subjective health with physical health and functional health were lower in the old-old than in the young-old samples, whereas associations of subjective health with mental health were stronger in older samples. Furthermore, the size of the association between subjective and objective health varied by the method of assessment of objective health, showing highest associations with symptom checklists and results of medical examinations due to strict protocols.

Standardized tests of heart rate variability: normal ranges obtained from 309 healthy humans, and effects of age, gender, and heart rate.

Abstract: The authors undertook this study to determine the effects of age, gender, and heart rate (HR) on the results of cardiac autonomic function tests for measuring heart rate variability (HRV) in a large sample of healthy subjects (n = 309). Conventional tests (deep breathing, maximum/minimum 30:15 ratio), and a standardized 5-minute resting study, including spectral analysis of HR, were used. The main findings included (1) the indices of all tests, except for the ratio of the low- (LF) to high-frequency (HF) spectral power (LF/HF ratio) and HR itself, are inversely related to age in both sexes; (2) the 5-minute spectral bands (except for the LF/HF ratio), the variation coefficient, expiratory-inspiratory ratio during deep breathing, and the maximum/minimum 30:15 ratio are independent of HR; (3) women up to the age of 55 years have a higher resting HR compared with men; (4) young and middle-aged women show a significantly lower LF power and LF/HF ratio compared with age-matched men, whereas no significant gender differences are observed in the absolute HF power. The authors computed age- and gender-dependent normal values for each of the HRV indices studied here and discuss the clinical consequences arising from gender differences in HRV.

Nanodissection of human chromosomes with near-infrared femtosecond laser pulses.

Abstract: Near-infrared laser pulses of a compact 80-MHz femtosecond laser source at 800 nm, a mean power of 15-100 mW, 170-fs pulse width, and millisecond beam dwell times at the target have been used for multiphoton-mediated nanoprocessing of human chromosomes. By focusing of the laser beam with high-numerical-aperture objectives of a scanning microscope to diffraction-limited spots and with light intensities of terawatts per cubic centimeter, precise submicrometer holes and cuts in human chromosomes have been processed by single-point exposure and line scans. A minimum FWHM cut size of ~100 nm during a partial dissection of chromosome 1, which is below the diffraction-limited spot size, and a minimum material removal of ~0.003mum (3) were determined by a scanning-force microscope. The plasma-induced ablated material corresponds to ~1/400 of the chromosome 1 volume and to ~65x10(3) base pairs of chromosomal DNA. A complete dissection could be performed with FWHM cut sizes below 200 nm. High-repetition-frequency femtosecond lasers at low mean power in combination with high-numerical-aperture focusing optics appear therefore as appropriate noncontact tools for nanoprocessing of bulk and (or) surfaces of transparent materials such as chromosomes. In particular, the noninvasive inactivation of certain genomic regions on single chromosomes within living cells becomes possible.

The antioxidant network of the stratum corneum.

Abstract: Many studies have demonstrated beneficial health effects of topical antioxidant application; however, the underlying mechanisms are not well understood. To better understand the protective mechanism of oxogenous anti-oxidants, it is important to clarify the physiological distribution, activity and regulation of antioxidants. Also, the generation of ROS by the resident and transient microbial flora and their interaction with cutaneous antioxidants appears to be of relevance for the redox properties of skin. Our studies have demonstrated that alpha-tocopherol is, relative to the respective levels in the epidermis, the major antioxidant in the human SC, that alpha-tocopherol depletion is a very early and sensitive biomarker of environmentally induced oxidation and that a physiological mechanism exists to transport alpha-tocopherol to the skin surface via sebaceous gland secretion. Furthermore, there is conclusive evidence that the introduction of carbonyl groups into human SC keratins is inducible by oxidants and that the levels of protein oxidation increase towards outer SC layers. The demonstration of specific redox gradients within the human SC may contribute to a better understanding of the complex biochemical processes of keratinization and desquamation. Taken together, the presented data suggest that, under conditions of environmentally challenged skin or during prooxidative dermatological treatment, topical and/or systemic application of antioxidants could support physiological mechanisms to maintain or restore a healthy skin barrier. Growing experimental evidence should lead to the development of more powerful pharmaceutical and cosmetic strategies involving antioxidant formulations to prevent UV-induced carcinogenesis and photoaging as well as to modulate desquamatory skin disorders.

Assessment of the safety of recombinant tissue factor pathway inhibitor in patients with severe sepsis: a multicenter, randomized, placebo-controlled, single-blind, dose escalation study.

Abstract: Objective To identify a safe and potentially effective recombinant tissue factor pathway inhibitor (rTFPI) dose for further clinical evaluation in patients with severe sepsis.Design Prospective, randomized, single-blind, placebo-controlled, dose escalation, multicenter, multinational phase II clinic

High-resolution BOLD venographic imaging: a window into brain function.

Abstract: This paper reviews the recent development of a new high-resolution magnetic resonance imaging approach to visualizing small veins in the human brain with diameters in the sub-millimeter range, which is smaller than a voxel. It briefly introduces the physical background of the underlying bulk magnetic susceptibility effects, on which this approach is based, and it demonstrates the successful application of the method for imaging different intracranial lesions, like venous anomalies, arteriovenous malformations and brain tumors. The susceptibility difference between venous blood and the surrounding tissue is used to generate contrast. Using this method it is possible to visualize draining veins in lesions better than conventional magnetic resonance imaging methods, which often require application of a contrast medium or even conventional catheter angiography. Limitations of the method are discussed. The ability to highlight deoxygenated blood with high spatial resolution yields important vascular parameters which may be helpful for improved modeling of MR signal changes during functional brain activation, it may lead to a better understanding of brain function in diseased states, or it may even offer the possibility of differentiating benign from malignant tumors non-invasively.

Steps toward interstellar silicate mineralogy - VI. Dependence of crystalline olivine IR spectra on iron content and particle shape

Abstract: Crystalline olivines are an important component of silicate dust particles in space. ISO observations revealed the presence of crystalline silicates in comets, protoplanetary accretion disks, and outflows from evolved stars. For the interpretation of astronomical spectra, the relevant material data at a variety of temperatures and over a broad wavelength range, are urgently needed. In contrast to this need, optical properties of the astronomically interesting olivines are scarcely available at present. In order to close this gap, we studied the optical properties of three minerals of the olivine group by reflection spectroscopy on single crystals in the infrared spectral range. We measured the iron endmember (fayalite, ), an Mg-rich olivine (), and the magnesium endmember (forsterite, ) of the series. For a direct comparison with astronomical observations, we present calculated mass absorption coefficients in the Rayleigh limit for different shapes and varying iron content of the dust particles. The laboratory data together with a set of ISO data for envelopes around evolved stars (Molster 2000) are used to constrain the properties of circumstellar silicates. We find that essentially all band positions are shifted to larger wavelengths with increasing iron content. The particle shape influences very significantly the strong bands such as the B: mode that appears as the "11.4 μ m" band of forsterite, whereas e.g. the two FIR modes longward of 40 μ m remain practically unaffected by the particle shape but shift due to increasing iron content. The comparison with the band positions in ISO spectra points to the presence of olivine crystals strongly elongated along the crystallographic c -axis. In addition, we apply the calculated mass absorption coefficients to evaluate transmission measurements of particles embedded in a matrix -a technique which is frequently used in laboratory astrophysics. All data shown in this paper will be made available in digital form via the electronic database http://www.astro.uni-jena.de.

Semaphorin 3A-vascular endothelial growth factor-165 balance mediates migration and apoptosis of neural progenitor cells by the recruitment of shared receptor.

Abstract: The dynamic and coordinated interaction between cells and their microenvironment controls cell migration, proliferation, and apoptosis, mediated by different cell surface molecules. We have studied the response of a neuroectodermal progenitor cell line, Dev, to a guidance molecule, semaphorin 3A (Sema3A), described previously as a repellent-collapsing signal for axons, and we have shown that Sema3A acts as a repellent guidance cue for migrating progenitor cells and, on prolonged application, induces apoptosis. Both repulsion and induction of cell death are mediated by neuropilin-1, the ligand-binding component of the Sema3A receptor. The vascular endothelial growth factor, VEGF165, antagonizes Sema3A-induced apoptosis and promotes cell survival, migration, and proliferation. Surprisingly, repulsion by Sema3A also depends on expression of VEGFR1, a VEGF165 receptor, expressed in Dev cells. Moreover, we found that these repulsive effects of Sema3A require tyrosine kinase activity, which can be attributed to VEGFR1. These results indicate that the balance between guidance molecules and angiogenic factors can modulate the migration, apoptosis (or survival), and proliferation of neural progenitor cells through shared receptors.

Guidelines for molecular genetic detection of susceptibility to malignant hyperthermia

Abstract: Malignant hyperthermia (MH) is a potentially fatal pharmacogenetic disease triggered by several anaesthetic agents. The in vitro muscle contracture test (IVCT) is the standard test to establish an individual's risk of susceptibility to MH. Clinical practitioners and geneticists of the European MH Group have agreed on the present guidelines for the detection of MH susceptibility using molecular genetic techniques and/or IVCT to predict the risk of MH.

Randomized, placebo-controlled trial of the anti-tumor necrosis factor antibody fragment afelimomab in hyperinflammatory response during severe sepsis: The RAMSES Study

Abstract: Objective: This study investigated whether treatment with the anti-tumor necrosis factor-or monoclonal antibody afelimomab would improve survival in septic patients with serum interleukin (IL)-6 concentrations of >1000 pg/ml, Design: Multicenter, double-blind, randomized, placebo-controlled study. Setting: Eighty-four intensive care units in academic medical centers in Europe and Israel. Patients: A total of 944 septic patients were screened and stratified by the results of a rapid qualitative immunostrip test for serum IL-6 concentrations. Patients with a positive test kit result indicating IL-6 concentrations of >1000 pg/mL were randomized to receive either afelimomab (n = 224) or placebo (n = 222), Patients with a negative IL-6 test (n = 498) were not randomized and were followed up for 28 days. Interventions: Treatment consisted of 15-min infusions of 1 mg/kg afelimomab or matching placebo every 8 hrs for 3 days. Standard surgical and intensive care therapy was otherwise delivered. Measurements and Main Results:The study was terminated prematurely after an interim analysis estimated that the primary efficacy end points would not be met. The 28-day mortality rate in the nonrandomized patients (39.6%, 197 of 498) was significantly lower (p <.001) than that found in the randomized patients (55.8%, 249 of 446). The mortality rates in the IL-6 test kit positive patients randomized to afelimomab and placebo were similar, 54.0% (121 of 224) vs, 57.7% (128 of 222), respectively. Treatment with afelimomab was not associated with any particular adverse events. Conclusions: The IL-6 immunostrip test identified two distinct sepsis populations with significantly different mortality rates. A small (3.7%) absolute reduction in mortality rate was found in the afelimomab-treated patients. The treatment difference did not reach statistical significance.

Prevalence of a Common Point Mutation in the Dihydropyrimidine Dehydrogenase (DPD) Gene within the 5′-Splice Donor Site of Intron 14 in Patients with Severe 5-Fluorouracil (5-FU)- related Toxicity Compared with Controls

Abstract: Deficiency of dihydropyrimidine dehydrogenase (DPD), the rate-limiting enzyme in 5-fluorouracil (5-FU) catabolism, has been linked to toxic side effects of 5-FU The most prominent mutation of the DPD gene resulting in severe DPD deficiency is a G to A mutation in the GT 5'-splice recognition site of intron 14 (exon 14-skipping mutation) The corresponding mRNA lacks exon 14, and the enzymatic activity of the translated DPD protein is virtually absent We developed a reverse transcription-PCR-based assay suitable for routine identification of the exon 14-skipping mutation and screened a control cohort of 851 Caucasian individuals as well as a cohort of 25 cancer patients reported by their physicians to have suffered from WHO grades 3-4 toxicity upon 5-FU chemotherapy Within the control cohort, in total, eight heterozygotes were detected (094%): one heterozygote in 51 healthy donors, (196%); five heterozygotes in 572 hospital patients (087%); and two heterozygotes in 228 colorectal tumor patients (088%) Among the 25 patients with severe 5-FU-related toxicity, 5 (20%) were heterozygous and 1 (4%) was homozygous for the exon 14-skipping mutation All six patients had experienced WHO grade 4 myelosuppression Lethal outcome was seen in the homozygous and two of the heterozygous cases We conclude that carriers of the DPD exon 14-skipping mutation are at significantly increased risk to experience life-threatening myelosuppression upon 5-FU treatment, even when the allelic status is heterozygous These data lead us to suggest routine testing for the exon 14-skipping mutation before 5-FU treatment

Electromagnetic Heating of Breast Tumors in Interventional Radiology: In Vitro and in Vivo Studies in Human Cadavers and Mice

Abstract: PURPOSE: To assess relevant parameters for the minimally invasive elimination of breast tumors by using a selective application of magnetite and exposure of the breast to an alternating magnetic field. MATERIALS AND METHODS: The specific absorption rate (SAR) of different magnetite samples was determined calorimetrically. Temperature elevations based on magnetite mass (7–112 mg) and magnetic field amplitude (1.2–6.5 kA/m; frequency, 400 kHz) were investigated by using human breast tissue. Parameter combinations (21 mg ± 9 [SD], 242-second magnetic field exposure, 6.5-kA/m amplitude) were tested in 10 immunodeficient mice bearing human adenocarcinomas (MX-1 cells). Histologic sections of heated tumor tissue were analyzed. RESULTS: SAR data of different magnetite particle types ranged from 3 to 211 W/g. Temperature elevation (ΔT) as a function of the magnetite mass increased linearly up to 28 mg; at higher masses, a saturation of ΔT was observed at nearly 88°C. The dependence of ΔT on magnetic field amplitu...