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Background: Biological psychiatry aims to understand mental disorders in terms of altered neurobiological pathways. However, for one of the most prevalent and disabling mental disorders, Major Depressive Disorder (MDD), patients only marginally differ from healthy individuals on the group-level. Whether Precision Psychiatry can solve this discrepancy and provide specific, reliable biomarkers remains unclear as current Machine Learning (ML) studies suffer from shortcomings pertaining to methods and data, which lead to substantial over-as well as underestimation of true model accuracy.
Methods: Addressing these issues, we quantify classification accuracy on a single-subject level in N=1,801 patients with MDD and healthy controls employing an extensive multivariate approach across a comprehensive range of neuroimaging modalities in a well-curated cohort, including structural and functional Magnetic Resonance Imaging, Diffusion Tensor Imaging as well as a polygenic risk score for depression.
Findings Training and testing a total of 2.4 million ML models, we find accuracies for diagnostic classification between 48.1% and 62.0%. Multimodal data integration of all neuroimaging modalities does not improve model performance. Similarly, training ML models on individuals stratified based on age, sex, or remission status does not lead to better classification. Even under simulated conditions of perfect reliability, performance does not substantially improve. Importantly, model error analysis identifies symptom severity as one potential target for MDD subgroup identification.
Interpretation: Although multivariate neuroimaging markers increase predictive power compared to univariate analyses, single-subject classification – even under conditions of extensive, best-practice Machine Learning optimization in a large, harmonized sample of patients diagnosed using state-of-the-art clinical assessments – does not reach clinically relevant performance. Based on this evidence, we sketch a course of action for Precision Psychiatry and future MDD biomarker research.
Immune-modulating therapy is a promising therapy for patients with cholangiocarcinoma (CCA). Microsatellite instability (MSI) might be a favorable predictor for treatment response, but comprehensive data on the prevalence of MSI in CCA are missing. The aim of the current study was to determine the prevalence of MSI in a German tertiary care hospital. Formalin-fixed paraffin-embedded tissue samples, obtained in the study period from 2007 to 2015 from patients with CCA undergoing surgical resection with curative intention at Johann Wolfgang Goethe University hospital, were examined. All samples were investigated immunohistochemically for the presence of MSI (expression of MLH1, PMS2, MSH2, and MSH6) as well as by pentaplex polymerase chain reaction for five quasimonomorphic mononucleotide repeats (BAT-25, BAT-26, NR-21, NR-22, and NR-24). In total, 102 patients were included, presenting intrahepatic (n = 35, 34.3%), perihilar (n = 42, 41.2%), and distal CCA (n = 25, 24.5%). In the immunohistochemical analysis, no loss of expression of DNA repair enzymes was observed. In the PCR-based analysis, one out of 102 patients was found to be MSI-high and one out of 102 was found to be MSI-low. Thus, MSI seems to appear rarely in CCA in Germany. This should be considered when planning immune-modulating therapy trials for patients with CCA.
Cutaneous T cell lymphomas (CTCLs) represent a heterogeneous group of T cell lymphomas that primarily affect the skin. The most frequent forms of CTCL are mycosis fungoides and Sézary syndrome. Both are characterized by frequent recurrence, developing chronic conditions and high mortality with a lack of a curative treatment. In this study, we evaluated the effect of short-chain, cell-permeable C6 Ceramide (C6Cer) on CTCL cell lines and keratinocytes. C6Cer significantly reduced cell viability of CTCL cell lines and induced cell death via apoptosis and necrosis. In contrast, primary human keratinocytes and HaCaT keratinocytes were less affected by C6Cer. Both keratinocyte cell lines showed higher expressions of ceramide catabolizing enzymes and HaCaT keratinocytes were able to metabolize C6Cer faster and more efficiently than CTCL cell lines, which might explain the observed protective effects. Along with other existing skin-directed therapies, C6Cer could be a novel well-tolerated drug for the topical treatment of CTCL.
A list of authors and their affiliations appears at the end of the paper New-particle formation is a major contributor to urban smog, but how it occurs in cities is often puzzling. If the growth rates of urban particles are similar to those found in cleaner environments (1–10 nanometres per hour), then existing understanding suggests that new urban particles should be rapidly scavenged by the high concentration of pre-existing particles. Here we show, through experiments performed under atmospheric conditions in the CLOUD chamber at CERN, that below about +5 degrees Celsius, nitric acid and ammonia vapours can condense onto freshly nucleated particles as small as a few nanometres in diameter. Moreover, when it is cold enough (below −15 degrees Celsius), nitric acid and ammonia can nucleate directly through an acid–base stabilization mechanism to form ammonium nitrate particles. Given that these vapours are often one thousand times more abundant than sulfuric acid, the resulting particle growth rates can be extremely high, reaching well above 100 nanometres per hour. However, these high growth rates require the gas-particle ammonium nitrate system to be out of equilibrium in order to sustain gas-phase supersaturations. In view of the strong temperature dependence that we measure for the gas-phase supersaturations, we expect such transient conditions to occur in inhomogeneous urban settings, especially in wintertime, driven by vertical mixing and by strong local sources such as traffic. Even though rapid growth from nitric acid and ammonia condensation may last for only a few minutes, it is nonetheless fast enough to shepherd freshly nucleated particles through the smallest size range where they are most vulnerable to scavenging loss, thus greatly increasing their survival probability. We also expect nitric acid and ammonia nucleation and rapid growth to be important in the relatively clean and cold upper free troposphere, where ammonia can be convected from the continental boundary layer and nitric acid is abundant from electrical storms.
Eosinophilic cholangitis is a potentially underdiagnosed etiology in indeterminate biliary stricture
(2017)
AIM: To investigate presence and extent of eosinophilic cholangitis (EC) as well as IgG4-related disease in patients with indeterminate biliary stricture (IBS).
METHODS: All patients with diagnosis of sclerosing cholangitis (SC) and histopathological samples such as biopsies or surgical specimens at University Hospital Frankfurt from 2005-2015 were included. Histopathological diagnoses as well as further clinical course were reviewed. Tissue samples of patients without definite diagnosis after complete diagnostic work-up were reviewed regarding presence of eosinophilic infiltration and IgG4 positive plasma cells. Eosinophilic infiltration was as well assessed in a control group of liver transplant donors and patients with primary sclerosing cholangitis.
RESULTS: one hundred and thirty-five patients with SC were included. In 10/135 (13.5%) patients, no potential cause of IBS could be identified after complete diagnostic work-up and further clinical course. After histopathological review, a post-hoc diagnosis of EC was established in three patients resulting in a prevalence of 2.2% (3/135) of all patients with SC as well as 30% (3/10) of patients, where no cause of IBS was identified. 2/3 patients with post-hoc diagnosis of EC underwent surgical resection with suspicion for malignancy. Diagnosis of IgG4-related cholangitis was observed in 7/135 patients (5.1%), whereas 3 cases were discovered in post-hoc analysis. 6/7 cases with IgG4-related cholangitis (85.7%) presented with eosinophilic infiltration in addition to IgG4 positive plasma cells. There was no patient with eosinophilic infiltration in the control group of liver transplant donors (n = 27) and patients with primary sclerosing cholangitis (n = 14).
CONCLUSION: EC is an underdiagnosed benign etiology of SC and IBS, which has to be considered in differential diagnosis of IBS.
Genetic heterogeneity of primary lesion and metastasis in small intestine neuroendocrine tumors
(2018)
Data on intratumoral heterogeneity of small intestine neuroendocrine tumors (SI-NETs) and related liver metastasis are limited. The aim of this study was to characterize genetic heterogeneity of 5 patients with SI-NETs. Therefore, formalin-fixed, paraffin-embedded tissue samples of primary and metastatic lesions as well as benign liver of five patients with synchronously metastasized, well differentiated SI-NETs were analyzed with whole exome sequencing. For one patient, chip based 850k whole DNA methylome analysis was performed of primary and metastatic tumor tissue as well as control tissue. Thereby, 156 single nucleotide variants (SNVs) in 150 genes were identified and amount of mutations per sample ranged from 9–34 (mean 22). The degree of common (0–94%) and private mutations per sample was strongly varying (6–100%). In all patients, copy number variations (CNV) were found and the degree of intratumoral heterogeneity of CNVs corresponded to SNV analysis. DNA methylation analysis of a patient without common SNVs revealed a large overlap of common methylated CpG sites. In conclusion, SI-NET primary and metastatic lesions show a highly varying degree of intratumoral heterogeneity. Driver events might not be detectable with exome analysis only, and further comprehensive studies including whole genome and epigenetic analyses are warranted.