Biomedical subjects

S Frey

Publications and source records attributed to S Frey.

At least 19 recordsLinked to original sources

PubMed2026

Efficacy of prescription-eligible digital health applications for depression and generalized anxiety disorder in Germany: a systematic review and meta-analysis.

In Germany, prescription-eligible digital mental health applications (DiGA) were introduced in 2020 as promising interventions to address, among others, depression and anxiety disorders, two of the most prevalent mental health conditions worldwide. Despite growing interest in DiGAs, their overall efficacy remains uncertain. This study aimed to systematically evaluate and quantify the efficacy of prescription-eligible digital interventions for depression and generalized anxiety disorder by synthesizing evidence from randomized controlled trials (19 trials; total N = 4,078; pooled mean age = 38.7 years, SD = 12.1). Here we show that prescription-eligible digital applications for depression and generalized anxiety disorder reduce symptom severity compared with control conditions. For depression, effects were observed both immediately after the intervention (number of apps = 5; k = 17; SMD = - 0.49; 95% CI - 0.65 to - 0.32) and at follow-up (number of apps = 1; k = 4; SMD = - 0.35; 95% CI - 0.46 to - 0.29), while evidence for generalized anxiety disorder was limited due to a small number of available studies (number of studies = 2). These findings support the integration of evidence-based digital tools into mental health treatment strategies in Germany. However, the available evidence is currently dominated by a small number of applications, particularly Deprexis, and should therefore not be interpreted as equally representative of all DiGAs currently listed for depression in Germany. The findings also highlight methodological limitations of current research and underscore the need for real-world evaluations, which address not only efficacy but also the effectiveness, content, quality and implementation.

Generalized Anxiety Disorder↗

PubMed2006

Chemosensory event-related potentials in relation to side of stimulation, age, sex, and stimulus concentration.

OBJECTIVE: For chemosensory event-related potentials (ERP) significant effects of age and sex have been demonstrated. The aim of the present study was to assess the effects of stimulus concentration, side of stimulation, and sex on the topographical distribution of chemosensory ERP in a large group of subjects stratified for different age groups. In addition, psychophysical measures of both olfactory and trigeminal function should be assessed in greater detail compared to previous work. METHODS: A total of 95 healthy subjects participated in the study. Olfactory functions were tested using the 'Sniffin' Sticks' comprising tests of odor identification, odor discrimination, and odor threshold. Trigeminal sensitivity was assessed on a psychophysical level using a lateralization paradigm. ERP to the olfactory stimulant H2S and the trigeminal irritant CO2 were recorded; stimuli were presented in different concentrations to the left and right nostril. RESULTS: Olfactory thresholds exhibited an age-related increase while the outcome of psychophysical trigeminal tests was not significantly affected by age. In contrast, there was no significant main effect of the factor 'sex' for olfactory tests, while women scored higher than men in the trigeminal task. ERP to olfactory and trigeminal stimuli exhibited a relationship to stimulus concentration, age, and sex with youngest women showing largest amplitudes and shortest latencies. There was no significant main effect of left- or right-sided stimulation on ERP. Measures of olfactory function were found to correlate with parameters of olfactory ERP even when controlling for the subject's age. In addition, correlations between scores in the lateralization task and parameters of the trigeminal ERP were found. CONCLUSIONS: Based on electrophysiological data obtained in a large sample size the present results established an age-related loss of olfactory and trigeminal function, which appears to be almost linear. Further, the present results emphasize that responses to chemosensory stimuli are related to sex, while the side of stimulation does not play a major role in the presently used paradigm. Finally, these data establish the lateralization paradigm as a psychophysical tool to investigate intranasal trigeminal function. SIGNIFICANCE: The present results obtained in a representative group of healthy subjects establishes a comprehensive set of data, which will serve as reference for future work in this area of research.

Adolescent↗

PubMed2005

Multifilamentation transmission through fog.

The influence of atmospheric aerosols on the filamentation patterns created by TW laser beams over 10 m propagation scales is investigated, both experimentally and numerically. From the experimental point of view, it is shown that dense fogs dissipate quasi-linearly the energy in the beam envelope and diminish the number of filaments in proportion. This number is strongly dependent on the power content of the beam. The power per filament is evaluated to about 5 critical powers for self-focusing in air. From the theoretical point of view, numerical computations confirm that a dense fog composed of micrometric droplets acts like a linear dissipator of the wave envelope. Beams subject to linear damping or to collisions with randomly-distributed opaque droplets are compared.

Journal Article↗

PubMed2005

Supercontinuum emission and enhanced self-guiding of infrared femtosecond filaments sustained by third-harmonic generation in air.

The long-range propagation of two-colored femtosecond filaments produced by an infrared (IR) ultrashort pulse exciting third harmonics (TH) in the atmosphere is investigated, both theoretically and experimentally. First, it is shown that the coupling between the pump and TH components is responsible for a wide spectral broadening, extending from ultraviolet (UV) wavelengths (220 nm) to the mid-IR (4.5 microm). Supercontinuum generation takes place continuously as the laser beam propagates, while TH emission occurs with a conversion efficiency as high as 0.5%. Second, the TH pulse is proven to stabilize the IR filament like a saturable quintic nonlinearity through four-wave mixing and cross-phase modulation. Third, the filamentation is accompanied by a conical emission of the beam, which becomes enlarged at UV wavelengths. These properties are revealed by numerical simulations and direct experimental observations performed from the Teramobile laser facility.

Journal Article↗

PubMed2004

Irradiation sensitivity of self-assembled monolayers with an introduced "weak link".

The irradiation sensitivity of n-alkanethiolate SAMs can be enhanced by the incorporation of an irradiation-sensitive functionality as a predetermined breaking point into the alkyl chain. Following this general strategy, several different sulfur-derived functional entities with a variable position in the alkyl chain were tested. In some cases, the incorporation of these entities resulted in a noticeable enhancement of the irradiation-induced desorption (by about 30%), even though the chains were not exclusively cut at the position of the incorporated group, but the scission events related to the "weak links" were just added to those in the alkyl matrix. The position of the incorporated group along the alkyl chain was found to be most essential for its performance as a weak link; the enhancement of irradiation-induced desorption was observed only when the groups were placed close to the SAM-ambient interface.

Journal Article↗

PubMed2004

Functional abnormalities in symptomatic concussed athletes: an fMRI study.

Our aim was to quantify with functional magnetic resonance imaging (fMRI) changes in brain activity in concussed athletes and compare the results with those of normal control subjects. Regional brain activations associated with a working memory task were obtained from a group of concussed athletes (15 symptomatic, 1 asymptomatic) and eight matched control subjects, using blood oxygen level dependent (BOLD) fMRI. The average percent signal change from baseline to working memory condition in each region of interest was computed. Symptomatic concussed athletes demonstrated task-related activations in some but not all the regions of interest, even when they performed as well as the control subjects. Furthermore, several concussed athletes had additional increases in activity outside the regions of interest, not seen in the control group. Quantitative analysis of BOLD signals within regions of interest revealed that, in general, concussed athletes had different BOLD responses compared to the control subjects. The task-related activation pattern of the one symptom-free athlete was comparable to that of the control group. We also repeated the study in one athlete whose symptoms had resolved. On the first study, when he was still symptomatic, less task-related activations were observed. On follow-up, once his symptoms had disappeared, the task-related activations became comparable to those of the control group. These results demonstrate the potential of fMRI, in conjunction with the working memory task, to identify an underlying pathology in symptomatic concussed individuals with normal structural imaging results.

Adult↗

PubMed2004

Regulation of the phosphodiesterase PDE4B3-isotype during long-term potentiation in the area dentata in vivo.

Hippocampal long-term potentiation (LTP) is the most prominent cellular model underlying learning and memory formation. However, which cellular processes are involved in maintaining LTP remains largely unknown. We have previously detailed temporal modulations of cyclic adenosine monophosphate (cAMP) and a cAMP-specific phosphodiesterase, PDE4B3, after LTP-induction and its maintenance in hippocampal area CA1 in vitro. To test whether other hippocampal sub-structures are characterised by similar mechanisms, tissue from the area dentata of freely moving rats was analysed at different LTP-time points. The tissue was fractionated into three components, where PDE4B-levels and cAMP-concentrations were measured. In contrast with data obtained in area CA1, we now detail an LTP-specific translational, but not transcriptional regulation of PDE4B3 within the first 8 h after tetanization and present spatio-temporal changes of PDE4B proteins and cAMP that is LTP-specific.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2004

Holographic face models as planning tool in maxillofacial surgery.

The holographic facial profile scan is a new technique for creation of high-resolution, three-dimensional, realistic facial computer models which can be used for surgical planning and documentation in maxillofacial surgery. First, a holographic image of the patient is recorded using a pulsed laser system. In a second step, called holographic tomography, the real image of the patient's hologram is reconstructed by means of a continuous-wave laser. By moving a screen through the real three-dimensional image, it is sliced into a series of two-dimensional projections which are captured with a digital camera. The slices containing the specific two-dimensional information are superimposed to a three-dimensional surface model using special software. The extremely short exposure time of 35 nanoseconds for taking a holographic image is separated from the time-consuming rendering process of the surface model; thus, the obtained models are not affected by the movements of the patient.

Computer Simulation↗

PubMed2003

White-light filaments for atmospheric analysis.

Most long-path remote spectroscopic studies of the atmosphere rely on ambient light or narrow-band lasers. High-power femtosecond laser pulses have been found to propagate in the atmosphere as dynamically self-guided filaments that emit in a continuum from the ultraviolet to the infrared. This white light exhibits a directional behavior with enhanced backward scattering and was detected from an altitude of more than 20 kilometers. This light source opens the way to white-light and nonlinear light detection and ranging applications for atmospheric trace-gas remote sensing or remote identification of aerosols. Air ionization inside the filaments also opens promising perspectives for laser-induced condensation and lightning control. The mobile femtosecond-terawatt laser system, Teramobile, has been constructed to study these applications.

Journal Article↗

PubMed2003

Review of existing prophylaxis programs for 3880 first graders from Rhineland Palatinate, Germany.

A large study amongst 6-7 years old children was conducted in one of the German Federal States to evaluate the success of presently existing prophylaxis programs and to determine groups at high risk for dental caries. - A total of 3880 children (1844 girls and 2036 boys) received a dental exam while in first grade in the year 2000. 37.8% (n = 1465) of the students lived in a larger city (approximately 200000 inhabitants), 62.2% (n = 2415) of the students came from rural areas. The proportion of foreign children, mainly from Serbia, Croatia and Turkey, amounted to a total of 19.1% (n = 741). All children were cared for as part of a group dental prophylaxis program in their respective schools and were examined under the protocol of the dmf-t/DMF-T index. 53.4% (n = 2073) of the students had a naturally healthy dentition, with the percentage of boys (55.5%, n = 1129) being higher than that of girls (51.2%, n = 944). The percentage of the caries-free dentitions in the rural population was 56.1% (n = 1163) whereas the percentage amongst the urban students was 43.9% (n = 910). The percentage of naturally healthy dentitions was 60.8% (n = 1909) amongst German children, and their foreign classmates had 21.9% (n = 162) caries-free dentitions. 37.6% (n = 1459) of all children had carious lesions; the foreign children had carious defects in 69.7% (n = 517) of the cases and the German students in 30.1% (n = 944). 8.8% of all first graders surveyed had fully treated healthy dentitions. - Although the goal of the WHO to obtain caries-free dentitions amongst 5-6 year olds in 50% of the cases has been met in the year 2000, this study showed clearly that oral health was significantly worse for the majority of foreign children compared to the German school children.

Child↗

PubMed2003

Modulation of late phases of long-term potentiation in rat dentate gyrus by stimulation of the medial septum.

The prolonged maintenance of hippocampal long-term potentiation (LTP) seems to require heterosynaptic events during its induction. We have previously shown that stimulation of the basolateral nucleus of the amygdala (BLA) within a distinct time window can reinforce a transient early-LTP into a long-lasting late-LTP in the dentate gyrus (DG) in freely moving rats. We have shown that this reinforcement was dependent on beta-adrenergic and/or muscarinergic receptor activation and protein synthesis. However, since the BLA does not directly stimulate the DG the question remained by which inputs such heterosynaptic processes are triggered. We have now directly stimulated the medial septal pathway 15 min after induction of early-LTP in the DG and show that this input is capable of reinforcing early into late-LTP in a frequency-dependent manner. This septal reinforcement of DG LTP was dependent on beta-adrenergic receptor activation and protein synthesis. We suggest that the reinforcing effect of the BLA stimulation can, potentially, be mediated via the septal input to the DG, though it differs in its ability to induce or modulate functional plasticity.

Adrenergic beta-Antagonists↗

PubMed2002

Electronic diary for bipolar patients.

Long-term monitoring methods providing an overview of the course of bipolar disorder of individual patients are a clinical necessity at least for patients who require a combination therapy with drugs that have only proven their efficacy for monotherapy. The Life Chart Method (LCM) of the NIMH is an adequate method for this purpose. Unfortunately, due to data entry and management requirements, it is too expensive for everyday clinical use. The 'electronic diary for patients with bipolar disorder' is meant to provide a method to minimize the effort for detailed long-term monitoring of patients with bipolar affective disorder and thus make it available for the everyday clinical use for every bipolar patient.

Bipolar Disorder↗

PubMed2001

Reinforcement of early long-term potentiation (early-LTP) in dentate gyrus by stimulation of the basolateral amygdala: heterosynaptic induction mechanisms of late-LTP.

The basolateral amygdala (BLA) can influence distinct learning and memory formation. Hippocampal long-term potentiation (LTP), the most prominent cellular model of memory formation, can be modulated by stimulation of the BLA in its induction and early maintenance. However, it is not known how the late maintenance of LTP beyond its initial phases might be affected. Behavioral stimuli have been shown to result in a reinforcement of a transient early-LTP into a lasting potentiation. Here we show that BLA stimulation mimics the behavioral effects on early-LTP in freely moving rats when the BLA is activated within a time window of 30 min before or after tetanization of the perforant path. The reinforcement of LTP was blocked by inhibitors of muscarinergic and beta-adrenergic but not dopaminergic receptors and was dependent on translation. Through these heterosynaptic associative interactions, hippocampal sensory information can be stabilized by amygdaloidal influences.

Adrenergic beta-Antagonists↗

PubMed2001

Safety and immunogenicity of a canarypox-vectored human immunodeficiency virus Type 1 vaccine with or without gp120: a phase 2 study in higher- and lower-risk volunteers.

Live attenuated viral vectors that express human immunodeficiency virus (HIV) antigens are being developed as potential vaccines to prevent HIV infection. The first phase 2 trial with a canarypox vector (vCP205, which expresses gp120, p55, and protease) was conducted in 435 volunteers with and without gp120 boosting, to expand the safety database and to compare the immunogenicity of the vector in volunteers who were at higher risk with that in volunteers at lower risk for HIV infection. Neutralizing antibodies to the MN strain were stimulated in 94% of volunteers given vCP205 plus gp120 and in 56% of volunteers given vCP205 alone. CD8(+) cytotoxic T lymphocyte cells developed at some time point in 33% of volunteers given vCP205, with or without gp120. Phase 3 field trials with these or similar vaccines are needed, to determine whether efficacy in preventing HIV infection or in slowing disease progression among vaccinees who become infected is associated with the level and types of immune responses that were induced by the vaccines in this study.

AIDS Vaccines↗

PubMed2001

Scp160p, an RNA-binding, polysome-associated protein, localizes to the endoplasmic reticulum of Saccharomyces cerevisiae in a microtubule-dependent manner.

Scp160p is an RNA-binding protein containing 14 tandemly repeated heterogenous nuclear ribonucleoprotein K-homology domains, which are implicated in RNA binding. Scp160p interacts with free and membrane-bound polysomes that are dependent upon the presence of mRNA. Despite its presence on cytosolic polysomes, Scp160p is predominantly localized to the endoplasmic reticulum (ER). Accumulation of Scp160p-ribosome complexes at the ER requires the function of microtubules but is independent of the actin cytoskeleton. We propose that the multi-K-homology-domain protein Scp160p functions as an RNA binding platform, interacting with polysomes that are transported to the ER.

Actins↗

PubMed2001

Transcription, beta-like DNA polymerases and hypermutation.

This paper discusses two aspects of immunoglobulin (Ig) gene hypermutation. In the first approach, a transcription termination signal is introduced in an Ig light chain transgene acting as a mutation substrate, and transgenic lines are generated with control and mutant transgenes integrated in tandem. Analysis of transcription levels and mutation frequencies between mutant and control transgenes clearly dissociates transcription elongation and mutation, and therefore argues against models whereby specific pausing of the RNA polymerase during V gene transcription would trigger an error-prone repair process. The second part reports the identification of two novel beta-like DNA polymerases named Pol lambda and Pol mu, one of which (Pol mu) represents a good candidate for the Ig mutase due to its higher lymphoid expression and its similarity with the lymphoid enzyme terminal deoxynucleotidyl transferase. Peculiar features of the expression of this gene, including an unusual splicing variability and a splicing inhibition in response to DNA-damaging agents, are discussed.

Animals↗

PubMed2001

Production of the fungal biocontrol agent Ulocladium atrum by submerged fermentation: accumulation of endogenous reserves and shelf-life studies.

A method was developed for the induction of submerged conidiation of Ulocladium atrum Preuss (isolate 385) for the first time, using an oatmeal extract broth. Two inoculum types were produced by this process: spores and mycelial fragments. Spore production was stimulated by reducing the broth water potential (psi) to -2.1 MPa and adding 20 mM calcium chloride. In contrast, mycelial fragments were dominant at -7.0 MPa psi. Maximum total inoculum (mycelial fragments and conidia) yields were approximately 2 x 10(7) ml(-1) after 9 days incubation at 25 degrees C at 100 rpm. Biomass from liquid cultures responded to water-stress by accumulating increased concentrations of endogenous sugar alcohols (polyols), particularly glycerol. Long-term shelf-life studies showed that submerged inoculum from cultures subjected to an intermediate water-stress (-2.1 MPa psi) and containing enhanced levels of glycerol (> 300 mg g(-1) freeze-dried material) retained viability significantly better (P < 0.05) than that from unstressed cultures, when assessed on agar with fully available water. This level of viability was comparable to that of aerial U. atrum spores from a 4-week solid-substrate fermentation on oat grains. However, in contrast to aerial spores, the ability of submerged biomass to germinate in drier conditions declined significantly after 6 months.

Ascomycota↗

PubMed2000

Orbitofrontal cortex: A key prefrontal region for encoding information.

Little is known about the specific functional contribution of the human orbitofrontal cortex with regard to memory processing, although there is strong evidence from lesion studies in monkeys that it may play an important role. The present investigation measured changes in regional cerebral blood flow with positron emission tomography in normal human subjects who were instructed to commit to memory abstract visual patterns. The results indicated that the rostral orbitofrontal region (area 11), which is primarily linked with the anterior medial temporal limbic region and lateral prefrontal cortical areas, is involved in the process of encoding of new information.

Adult↗