Polygenic risk for schizophrenia converges on alternative polyadenylation as molecular mechanism underlying synaptic impairment

Schizophrenia (SCZ) is a genetically heterogenous psychiatric disorder of highly polygenic nature. Correlative evidence from genetic studies indicate that the aggregated effects of distinct genetic risk factor combinations found in each patient converge onto common molecular mechanisms. To prove this on a functional level, we employed a reductionistic cellular model system for polygenic risk by differentiating induced pluripotent stem cells (iPSCs) from 104 individuals with high polygenic risk load and controls into cortical glutamatergic neurons (iNs). Multi-omics profiling identified widespread differences in alternative polyadenylation (APA) in the 3' untranslated region of many synaptic transcripts between iNs from SCZ patients and healthy donors. On the cellular level, 3'APA was associated with a reduction in synaptic density of iNs. Importantly, differential APA was largely conserved between postmortem human prefrontal cortex from SCZ patients and healthy donors, and strongly enriched for transcripts related to synapse biology. 3'APA was highly correlated with SCZ polygenic risk and affected genes were significantly enriched for SCZ associated common genetic variation. Integrative functional genomic analysis identified the RNA binding protein and SCZ GWAS risk gene PTBP2 as a critical trans-acting factor mediating 3'APA of synaptic genes in SCZ subjects. Functional characterization of PTBP2 in iNs confirmed its key role in 3'APA of synaptic transcripts and regulation of synapse density. Jointly, our findings show that the aggregated effects of polygenic risk converge on 3'APA as one common molecular mechanism that underlies synaptic impairments in SCZ.

Massively parallel functional dissection of schizophrenia-associated noncoding genetic variants

Schizophrenia (SCZ) is a highly heritable mental disorder with thousands of associated genetic variants located mostly in the noncoding space of the genome. Translating these associations into insights regarding the underlying pathomechanisms has been challenging because the causal variants, their mechanisms of action, and their target genes remain largely unknown. We implemented a massively parallel variant annotation pipeline (MVAP) to perform SCZ variant-to-function mapping at scale in disease-relevant neural cell types. This approach identified 620 functional variants (1.7%) that operate in a highly developmental context and neuronal-activity-dependent manner. Multimodal integration of epigenomic and CRISPRi screening data enabled us to link these functional variants to target genes, biological processes, and ultimately alterations of neuronal physiology. These results provide a multistage prioritization strategy to map functional single-nucleotide polymorphism (SNP)-to-gene-to-endophenotype relations and offer biological insights into the context-dependent molecular processes modulated by SCZ-associated genetic variation.

Loratadine and analogues: discovery and preliminary structure-activity relationship of inhibitors of the amino acid transporter B(0)AT2

B(0)AT2, encoded by the SLC6A15 gene, is a transporter for neutral amino acids that has recently been implicated in mood and metabolic disorders. It is predominantly expressed in the brain, but little is otherwise known about its function. To identify inhibitors for this transporter, we screened a library of 3133 different bioactive compounds. Loratadine, a clinically used histamine H1 receptor antagonist, was identified as a selective inhibitor of B(0)AT2 with an IC50 of 4 μM while being less active or inactive against several other members of the SLC6 family. Reversible inhibition of B(0)AT2 was confirmed by electrophysiology. A series of loratadine analogues were synthesized to gain insight into the structure-activity relationships. Our studies provide the first chemical tool for B(0)AT2.

Effect of paroxetine on thyroid hormone levels in severely depressed patients

There are very divergent appraisals of the effect of antidepressants on thyroid parameters and their possible correlation with the response. Whereas there are numerous investigations of tricyclic antidepressants, so far, there are only limited data on the possible effect of serotonin-selective reuptake inhibitors on neuroendocrine parameters. The present study showed a significant reduction of 11. 2% in thyroxine during treatment with 20 mg paroxetine in 25 severely depressed patients.

Thyroid parameters during therapy with zotepine in delusional depression. Preliminary results

There are only few data on the effects of atpyical neuroleptics on thyroid function. In an open pilot study of 12 inpatients with delusional depression, thyroid hormone levels and TRH-TSH test were determined during neuroleptic treatment with zotepine. No significant changes in triiodothyronine (T3), thyroxine (T4) and delta-TSH levels were found in this observation period (28 days).

Centralization of low back pain and perceived functional outcome

McKenzie's methods for evaluating and treating low back pain are used often but studied little. When using the McKenzie system, it is important to observe signs of symptom movement to a central location (centralization). This study investigated the relationships between centralization of low back pain and/or radiculopathy and the subjects' rating of functional outcome. Thirty-six subjects with low back pain volunteered to participate and were evaluated and treated by six researchers. Subjects were tested initially and again 14 days after initiation of treatment using the Oswestry Low Back Pain Disability Questionnaire and the Performance Assessment and Capacity Testing Spinal Function Sort (SFS). Symptoms were monitored for the occurrence of "complete centralization." Of the 36 subjects, 25 showed complete centralization within 14 days. The SFS score changes were significantly higher for subjects who completely centralized (p = 0.015). The results supported the hypothesis that subjects who centralize will have improved functional outcome and, thus, quality of life. However, shorter time to occurrence of complete centralization does not necessarily correlate with improved outcome.

Trimipramine and maprotiline plasma levels during combined treatment with moclobemide in therapy-resistant depression

In an open pilot study of 21 therapy-resistant depressive inpatients, plasma levels of antidepressants were determined during treatment with a combination of moclobemide/ trimipramine (n = 15) and moclobemide/maprotiline (n = 6). After combined administration of trimipramine and moclobemide (MCB), a significant increase in the plasma level of trimipramine (39%) was observed. After combination of maprotiline with moclobemide, maprotiline levels were increased (25%, n.s.). The results show that moclobemide, as an inhibitor of isoenzymes of the cytochrome P 450 oxidase, can cause increases in the plasma levels of tricyclic and tetracyclic antidepressants. No correlation between the serum level of the antidepressants and treatment outcome was found in this open study.

[Bradycardia after beginning therapy with metoprolol and paroxetine]

Because of their low incidence of adverse effects SSRI are prescribed more and more frequently in patients with depressive disorders. SSRI inhibit different subsystems of cytochrome-P 450-oxydase. Especially during co-administration of SSRI with antipsychotic and antiarrhythmic drugs pharmacokinetic interactions have to be observed carefully. In this presentation a case of bradycardia after co-administration of paroxetine and metoprolol is reported. Drug history and a careful drug monitoring are necessary requirements to avoid serious adverse effects.

The effects of limb length discrepancy on subtalar joint kinematics during running

Physical therapists often use videography to accurately measure joint kinematics. The purpose of this study was to determine how the maximal calcaneal inversion and eversion angles are affected while running in individuals with a limb length difference between 1.27 cm (1/2 inch) and 1.9 cm (3/4 inch). Twelve subjects with a limb length difference were videotaped using 60-Hz digitized videography while running on a treadmill. Data were obtained for maximum calcaneal inversion and eversion values. Repeated measures analyses of variance were used to determine if significant differences were evident between the lower extremity. Significant differences were not found between the short and long limb for the maximum amount of calcaneal inversion and eversion range of motion. Since calcaneal inversion and eversion are important components of subtalar joint supination and pronation, respectively, the results suggest that subtalar joint kinematics were not significantly altered.

[The value of spiral computed tomography in the imaging of aortocoronary bypass vessels]

Spiral computer tomography (Sp-CT) was performed on 25 patients with 81 aorto-coronary bypasses, with persistent symptoms, following selective coronary angiography. The purpose was to determine to what extent Sp-CT is able to demonstrate patency or occlusion of individual bypasses. From the raw data, transverse sections and standardised 3D reconstructions were obtained. Statistical evaluation showed a sensitivity of 93% and a specificity of 100% with regard to patency. Sp-CT provides optimal contrast and complete demonstration of the bypass without movement artifacts from respiration. 3D reconstructions aid in the evaluation of complex anatomical situations but occasionally lead to incorrect diagnosis of stenoses or occlusions. Compared with other non-invasive procedures (conventional CT and NMR) Sp-CT has proved significantly better for the evaluation of bypass occlusions. Sp-CT cannot completely replace angiography but in some cases may be an acceptable alternative.