Refine
Year of publication
Document Type
- Article (16060)
- Part of Periodical (2820)
- Working Paper (2358)
- Preprint (2230)
- Doctoral Thesis (2069)
- Book (1736)
- Conference Proceeding (1172)
- Part of a Book (1071)
- Report (471)
- Review (165)
Language
- English (30347) (remove)
Keywords
- taxonomy (749)
- new species (449)
- morphology (178)
- Deutschland (142)
- Syntax (126)
- Englisch (120)
- distribution (117)
- biodiversity (103)
- inflammation (100)
- Deutsch (98)
Institute
- Medizin (5408)
- Physik (4069)
- Wirtschaftswissenschaften (1928)
- Frankfurt Institute for Advanced Studies (FIAS) (1865)
- Biowissenschaften (1568)
- Informatik (1503)
- Center for Financial Studies (CFS) (1499)
- Biochemie und Chemie (1090)
- Sustainable Architecture for Finance in Europe (SAFE) (1077)
- House of Finance (HoF) (714)
The single nucleotide polymorphism 118A>G of the human micro-opioid receptor gene OPRM1, which leads to an exchange of the amino acid asparagine (N) to aspartic acid (D) at position 40 of the extracellular receptor region, alters the in vivo effects of opioids to different degrees in pain-processing brain regions. The most pronounced N40D effects were found in brain regions involved in the sensory processing of pain intensity. Using the mu-opioid receptor-specific agonist DAMGO, we analyzed the micro-opioid receptor signaling, expression, and binding affinity in human brain tissue sampled postmortem from the secondary somatosensory area (SII) and from the ventral posterior part of the lateral thalamus, two regions involved in the sensory processing and transmission of nociceptive information. We show that the main effect of the N40D micro-opioid receptor variant is a reduction of the agonist-induced receptor signaling efficacy. In the SII region of homo- and heterozygous carriers of the variant 118G allele (n=18), DAMGO was only 62% as efficient (p=0.002) as in homozygous carriers of the wild-type 118A allele (n=15). In contrast, the number of [3H]DAMGO binding sites was unaffected. Hence, the micro-opioid receptor G-protein coupling efficacy in SII of carriers of the 118G variant was only 58% as efficient as in homozygous carriers of the 118A allele (p<0.001). The thalamus was unaffected by the OPRM1 118A>G SNP. In conclusion, we provide a molecular basis for the reduced clinical effects of opioid analgesics in carriers of mu-opioid receptor variant N40D.
The µ-opioid receptor is the primary target structure of most opioid analgesics and thus responsible for the predominant part of their wanted and unwanted effects. Carriers of the frequent genetic µ-opioid receptor variant N40D (allelic frequency 8.2 - 17 %), coded by the single nucleotide polymorphism A>G at position 118 of the µ-opioid receptor coding gene OPRM1 (OPRM1 118A>G SNP), suffer from a decreased opioid potency and from a higher need of opioid analgesics to reach adequate analgesia. The aim of the present work was to identify the mechanism by which the OPRM1 118A>G SNP decreases the opioid potency and to quantify its effects on the analgesic potency and therapeutic range of opioid analgesics.
To elucidate the consequences of the OPRM1 118A>G SNP for the effects of opioid analgesics, brain regions of healthy homozygous carriers of the OPRM1 118A>G SNP were identified by means of functional magnetic resonace imaging (fMRI), where the variant alters the response to opioid analgesics after painful stimulation. Afterwards, the µ-opioid receptor function was analyzed on a molecular level in post mortem samples of these brain regions. Finally, the consequences of the OPRM1 118A>G SNP for the analgesic and respiratory depressive effects of opioids were quantified in healthy carriers and non-carriers of OPRM1 118A>G SNP by means of experimental pain- and respiratory depression-models.
To identify pain processing brain regions, where the variant alters the response to opioid analgesics after painful stimulation, we investigated the effects of different alfentanil concentration levels (0, 25, 50 and 75 ng/ml) on pain-related brain activation achieved by short pulses (300 msec) of gaseous CO2 (66% v/v) delivered to the nasal mucosa using a 3.0 T magnetic head scanner in 16 non-carriers and nine homozygous carriers of the µ-opioid receptor gene variant OPRM1 118A>G. In brain regions associated with the processing of the sensory dimension of pain (pain intensity), such as the primary and secondary somatosensory cortices and the posterior insular cortex, the activation decreased linearly in relation to alfentanil concentrations, which was significantly less pronounced in OPRM1 118G carriers. In contrast, in brain regions known to process the affective dimension of pain (emotional dimension), such as the parahippocampal gyrus, amygdala and anterior insula, the pain-related activation disappeared already at the lowest alfentanil dose, without genotype differences.
Subsequently, we investigated the µ-opioid receptor-expression ([3H]-DAMGO saturation experiments, OPRM1 mRNA analysis by means of RT-PCR), the µ-opioid receptor affinity ([3H]-DAMGO saturation and competition experiments) and µ-opioid receptor signaling ([35S]- GTPγS binding experiments) in post mortem samples of the human SII-region, as a cortical projection region coding for pain intensity, and lateral thalamus, as an important region for nociceptive transmission. Samples of 22 non-carriers, 21 heterozygous and three homozygous carriers of OPRM1 118A>G SNP were included into the analysis. The receptor expression and receptor affinity of both brain regions did not differ between non-carriers and carriers of the variant N40D. In non-carriers, the µ-opioid receptors of the SII-region activated the receptor bound G-protein more efficiently than those of the thalamus (factor 1.55-2.27). This regional difference was missing in heterozygous (factor 0.78-1.66) and homozygous (factor 0.66-1.15) carriers of the N40D variant indicating a reduced receptor-G-protein-coupling in the SII-region.
Finally, the consequences of the alteration of µ-opioid receptor function in carriers and noncarriers of the genetic variant was investigated using pain- and respiratory depression-models. Therefore, 10 healthy non-carriers, four heterozygous and six homozygous carriers of the µ- opioid receptor variant N40D received an infusion of four different concentrations of alfentanil (0, 33.33, 66.66 and 100 ng/ml). At each concentration level, analgesia was assessed by means of electrically (5 Hz sinus 0 to 20 mA) and chemically (200 ms gaseous CO2 pulses applied to the nasal mucosa) induced pain, and respiratory depression was quantified by means of hypercapnic challenge according to Read and recording of the breathing frequency. The results showed that depending on the used pain model, both heterozygous and homozygous carriers of the variant N40D needed 2 – 4 times higher alfentanil concentrations to achieve the same analgesia as non-carriers. This increase seems to be at least for homozygous carriers unproblematic, because to reach a comparable respiratory depression as non-carriers, they needed 10-12 times higher alfentanil concentrations.
The results of this work demonstrate that the µ-opioid receptor variant N40D causes a regionally limited reduction of the signal transduction efficiency of µ-opioid receptors in brain regions involved in pain processing. Thus, the painful activation of sensory brain regions coding for pain intensity is not sufficiently suppressed by opioid analgesics in carriers of the variant N40D. Due to the insufficient suppression in hetero- and homozygous carriers of the variant N40D, the concentration of opioids has to be increased by a factor 2 - 4, in order to achieve the same analgesia as in non-carriers. At the same time, the respiratory depressive effects are decreased to a greater extent in homozygous carriers of the N40D variant as they need a 10 - 12 times higher opioid concentration to suffer from the same degree of respiratory depression as non-carriers. Due to the increased therapeutic range of opioid analgesics, an increase of the opioid dose seems to be harmless, at least for homozygous carriers of the N40D variant.
Based on a detailed case study of parallel grammar development distributed across two sites, we review some of the requirements for regression testing in grammar engineering, summarize our approach to systematic competence and performance profiling, and discuss our experience with grammar development for a commercial application. If possible, the workshop presentation will be organized around a software demonstration.
Hypomethylating agents decitabine and azacytidine are regarded as interchangeable in the treatment of acute myeloid leukemia (AML). However, their mechanisms of action remain incompletely understood, and predictive biomarkers for HMA efficacy are lacking. Here, we show that the bioactive metabolite decitabine triphosphate, but not azacytidine triphosphate, functions as activator and substrate of the triphosphohydrolase SAMHD1 and is subject to SAMHD1-mediated inactivation. Retrospective immunohistochemical analysis of bone marrow specimens from AML patients at diagnosis revealed that SAMHD1 expression in leukemic cells inversely correlates with clinical response to decitabine, but not to azacytidine. SAMHD1 ablation increases the antileukemic activity of decitabine in AML cell lines, primary leukemic blasts, and xenograft models. AML cells acquire resistance to decitabine partly by SAMHD1 up-regulation. Together, our data suggest that SAMHD1 is a biomarker for the stratified use of hypomethylating agents in AML patients and a potential target for the treatment of decitabine-resistant leukemia.
We welcome critical appraisals that help to provide balance; however, Dietrich et al. gave an unjustified reproach. We feel that Dietrich’s position is severely compromised because he serves as an expert for the bisphenol A (BPA) Industry Group (Brussels, Belgium). We would like to respond to the issues raised by Dietrich et al., as well as to their oversights and inappropriate interpretations of our findings...
Previous investigations have shown that bisphenol A (BPA) induces a superfeminization syndrome in the freshwater snail Marisa cornuarietis at concentrations as low as 1 μg/L. Superfemales are characterized by the formation of additional female organs, enlarged accessory sex glands, gross malformations of the pallial oviduct, and a stimulation of egg and clutch production, resulting in increased female mortality. However, these studies were challenged on the basis of incomplete experimentation. Therefore, the objective of the current approach was to bridge several gaps in knowledge by conducting additional experiments. In an initial series of experiments, study results from the reproductive phase of the snails were evaluated in the sub-micrograms per liter range. Before and after the spawning season, superfemale responses were observed [NOEC (no observed effect concentration) 7.9 ng/L, EC10 (effective concentration at 10%) 13.9 ng/L], which were absent during the spawning season. A further experiment investigated the temperature dependence of BPA responses by exposing snails at two temperatures in parallel. The adverse effect of BPA was at least partially masked at 27°C (EC10 998 ng/L) when compared with 20°C (EC10 14.8 ng/L). In M. cornuarietis, BPA acts as an estrogen receptor (ER) agonist, because effects were completely antagonized by a co-exposure to tamoxifen and Faslodex. Antiandrogenic effects of BPA, such as a significant decrease in penis length at 20°C, were also observed. Competitive receptor displacement experiments indicate the presence of androgen- and estrogen-specific binding sites. The affinity for BPA of the estrogen binding sites in M. cornuarietis is higher than that of the ER in aquatic vertebrates. The results emphasize that prosobranchs are affected by BPA at lower concentrations than are other wildlife groups, and the findings also highlight the importance of exposure conditions.
Background: Internet- and mobile-based interventions are most efficacious in the treatment of depression when they involve some form of guidance, but providing guidance requires resources such as trained personnel, who might not always be available (eg, during lockdowns to contain the COVID-19 pandemic).
Objective: The current analysis focuses on changes in symptoms of depression in a guided sample of patients with depression who registered for an internet-based intervention, the iFightDepression tool, as well as the extent of intervention use, compared to an unguided sample. The objective is to further understand the effects of guidance and adherence on the intervention’s potential to induce symptom change.
Methods: Log data from two convenience samples in German routine care were used to assess symptom change after 6-9 weeks of intervention as well as minimal dose (finishing at least two workshops). A linear regression model with changes in Patient Health Questionnaire (PHQ-9) score as a dependent variable and guidance and minimal dose as well as their interaction as independent variables was specified.
Results: Data from 1423 people with symptoms of depression (n=940 unguided, 66.1%) were included in the current analysis. In the linear regression model predicting symptom change, a significant interaction of guidance and minimal dose revealed a specifically greater improvement for patients who received guidance and also worked with the intervention content (β=–1.75, t=–2.37, P=.02), while there was little difference in symptom change due to guidance in the group that did not use the intervention. In this model, the main effect of guidance was only marginally significant (β=–.53, t=–1.78, P=.08).
Conclusions: Guidance in internet-based interventions for depression is not only an important factor to facilitate adherence, but also seems to further improve results for patients adhering to the intervention compared to those who do the same but without guidance.
Background: While the antidepressant efficacy of guided digital interventions has been proven in randomized controlled trials, findings from routine care are less clear. Low adherence rates are common and limit the potential effectiveness. Adherence has been linked to sociodemographic variables and the amount of guidance, but the role of the guide's profession and their work setting has not yet been studied for routine care.
Methods: Routinely collected log data from a digital intervention for depressed patients (iFightDepression tool) were analyzed in an exploratory manner. The sample is a convenience sample from routine care, where guidance is provided by general practitioners (GP), certified psychotherapists (PT) or medical doctors specialized in mental health. Log data from 2184 patients were analyzed and five usage parameters were extracted to measure adherence (first-to-last login, time on tool, number of sessions, workshops completed and minimal dose). Multiple logistic regression was used to analyze relations between the guide's profession and clinical context as well as other covariates and adherence and symptom change on a brief depression questionnaire (PHQ-9).
Results: The analyses showed a significant relation of guide profession and adherence. Guidance by PT was associated to the highest adherence scores (reference category). The odds ratios (ORs) of scoring above the median in each usage parameter for patients guided by GPs were 0.50–0.63 (all ps < 0.002) and 0.61–0.80 (p = .002–0.197) for MH. Higher age, initial PHQ-9 score and self-reported diagnosis of depression were also significantly associated with higher adherence scores. In a subsample providing enough data on the PHQ-9 (n = 347), no association of guide profession with symptom reduction was found. Instead, a greater reduction was observed for patients with a higher baseline PHQ-9 (β = −0. 39, t(341.75) = −8.814, p < .001) and for those who had achieved minimal dose (β = −2.42, t(340.34) = −4.174, P < .001) and those who had achieved minimal dose and scored high on time on tool (β = 0.22, t(341.75) = 1.965, P = .050).
Conclusion: Being guided by PT was associated with the highest adherence. The lowest adherence was observed in patients who were guided by GP. While no association of guide profession and symptom reduction was found in a subsample, greater adherence was associated with symptom reduction.