920 resultados para LINEX and quadratic loss functions


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BACKGROUND: Polymer as carrier substance for drugeluting stents (DES) has been accused of inducing inflammation and hypersensitivity reactions leading to restenosis and stent thrombosis. Thus, a new paclitaxel-eluting stent (PES) with aminoparylene as a carrier substance is tested in the present study. METHODS: In 10 pigs, stents were implanted in the epicardial coronary arteries: 1) bare-metal stents (BMS, control stent); 2) cobalt-chromium stents (CCS); and 3) PES. Stent length was 15 mm, and diameter was 3 mm. The animals were restudied after 6 weeks. Quantitative coronary angiography was performed at baseline and follow up. Minimum luminal diameter (MLD) and late loss were calculated in all animals. Histologic vessel lumen, intimal proliferation and restenosis were determined by morphometry. Disruption of the lamina elastica interna (LEI) and inflammatory reactions were assessed by histology. RESULTS: The MLD at baseline was 2.83 +/- 0.28 mm, and at follow up it was 2.29 +/- 0.44 (p < 0.05; n = 30). Late loss and angiographic restenosis were smallest in the CCS and largest in the PES (ns). Neointimal proliferation was similar for all 3 stents, ranging between 1.38 and 1.64 mm(2) (ns). There was a significant correlation between disruption of the LEI and inflammatory reactions. CONCLUSIONS: PTs with aminoparylene as a carrier substance show similar late loss and angiographic restenosis to that of BM and CCS. The incidence of inflammatory reactions (35% of all histologic sections) is similar in all stents, but highest in PES. The mechanism of this reaction is unclear, but may be either due to the drug itself, the disruption of the LEI or to a hypersensitivity reaction.

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Despite widespread use of species-area relationships (SARs), dispute remains over the most representative SAR model. Using data of small-scale SARs of Estonian dry grassland communities, we address three questions: (1) Which model describes these SARs best when known artifacts are excluded? (2) How do deviating sampling procedures (marginal instead of central position of the smaller plots in relation to the largest plot; single values instead of average values; randomly located subplots instead of nested subplots) influence the properties of the SARs? (3) Are those effects likely to bias the selection of the best model? Our general dataset consisted of 16 series of nested-plots (1 cm(2)-100 m(2), any-part system), each of which comprised five series of subplots located in the four corners and the centre of the 100-m(2) plot. Data for the three pairs of compared sampling designs were generated from this dataset by subsampling. Five function types (power, quadratic power, logarithmic, Michaelis-Menten, Lomolino) were fitted with non-linear regression. In some of the communities, we found extremely high species densities (including bryophytes and lichens), namely up to eight species in 1 cm(2) and up to 140 species in 100 m(2), which appear to be the highest documented values on these scales. For SARs constructed from nested-plot average-value data, the regular power function generally was the best model, closely followed by the quadratic power function, while the logarithmic and Michaelis-Menten functions performed poorly throughout. However, the relative fit of the latter two models increased significantly relative to the respective best model when the single-value or random-sampling method was applied, however, the power function normally remained far superior. These results confirm the hypothesis that both single-value and random-sampling approaches cause artifacts by increasing stochasticity in the data, which can lead to the selection of inappropriate models.

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Erosion of dentine causes mineral dissolution, while the organic compounds remain at the surface. Therefore, a determination of tissue loss is complicated. Established quantitative methods for the evaluation of enamel have also been used for dentine, but the suitability of these techniques in this field has not been systematically determined. Therefore, this study aimed to compare longitudinal microradiography (LMR), contacting (cPM) and non-contacting profilometry (ncPM), and analysis of dissolved calcium (Ca analysis) in the erosion solution. Results are discussed in the light of the histology of dentine erosion. Erosion was performed with 0.05 M citric acid (pH 2.5) for 30, 60, 90 or 120 min, and erosive loss was determined by each method. LMR, cPM and ncPM were performed before and after collagenase digestion of the demineralised organic surface layer, with an emphasis on moisture control. Scanning electron microscopy was performed on randomly selected specimens. All measurements were converted into micrometres. Profilometry was not suitable to adequately quantify mineral loss prior to collagenase digestion. After 120 min of erosion, values of 5.4 +/- 1.9 microm (ncPM) and 27.8 +/- 4.6 microm (cPM) were determined. Ca analysis revealed a mineral loss of 55.4 +/- 11.5 microm. The values for profilometry after matrix digestion were 43.0 +/- 5.5 microm (ncPM) and 46.9 +/- 6.2 (cPM). Relative and proportional biases were detected for all method comparisons. The mineral loss values were below the detection limit for LMR. The study revealed gross differences between methods, particularly when demineralised organic surface tissue was present. These results indicate that the choice of method is critical and depends on the parameter under study.

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OBJECTIVES: Dental erosion, the chemical dissolution of enamel without bacterial involvement, is a rarely reported manifestation of gastroesophageal reflux disease (GERD), as well as of recurrent vomiting and dietary habits. It leads to loss of tooth substance, hypersensitivity, functional impairment, and even tooth fracture. To date, dental erosions have been assessed using only very basic visual methods, and no evidence-based guidelines or studies exist regarding the prevention or treatment of GERD-related dental erosions. METHODS: In this randomized, double-blind study, we used optical coherence tomography (OCT) to quantify dental tissue demineralization and enamel loss before and after 3 weeks of acid-suppressive treatment with esomeprazole 20 mg b.i.d. or placebo in 30 patients presenting to the Berne University Dental Clinic with advanced dental erosions and abnormal acid exposure by 24-h esophageal pH manometry (defined as >4% of the 24-h period with pH<4). Enamel thickness, reflectivity, and absorbance as measures of demineralization were quantified by OCT before and after therapy at identical localizations on teeth with most severe visible erosions as well as several other predefined changes in teeth. RESULTS: The mean+/-s.e.m. decrease of enamel thickness of all teeth before and after treatment at the site of maximum exposure was 7.2+/-0.16 black trianglem with esomeprazole and 15.25+/-0.17black trianglem with placebo (P=0.013), representing a loss of 0.3% and 0.8% of the total enamel thickness, respectively. The change in optical reflectivity to a depth of 25 black trianglem after treatment was-1.122 +/-0.769 dB with esomeprazole and +2.059+/-0.534 dB with placebo (P 0.012), with increased reflectivity signifying demineralization. CONCLUSIONS: OCT non-invasively detected and quantified significantly diminished progression of dental tissue demineralization and enamel loss after only 3 weeks of treatment with esomeprazole 20 mg b.i.d. vs. placebo. This suggests that esomeprazole may be useful in counteracting progression of GERD-related dental erosions. Further validation of preventative treatment regimens using this sensitive detection method is required, including longer follow-up and correlation with quantitative reflux measures.

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Tumor suppressor genes, such as p53, RB, the INK4-ARF family and PML, suppress malignant transformation by regulating cell cycle progression, ensuring the fidelity of DNA replication and chromosomal segregation, or by inducing apoptosis in response to potentially deleterious events. In myeloid leukemia, hematopoietic differentiation resulting from highly coordinated, stage-wise expression of myeloid transcription and soluble signaling factors is disrupted leading to a block in terminal differentiation and uncontrolled proliferation. This virtually always involves functional inactivation or genetic disruption of one or several tumor suppressor genes in order to circumvent their checkpoint control and apoptosis-inducing functions. Hence, reactivation of tumor suppressor gene function has therapeutic potential and can possibly enhance conventional cytotoxic chemotherapy. In this review, we focus on the role of different tumor suppressor genes in myeloid differentiation and leukemogenesis, and discuss implications for therapy.

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Gastro-intestinal nematodes in ruminants, especially Haemonchus contortus, are a global threat to sheep and cattle farming. The emergence of drug resistance, and even multi-drug resistance to the currently available classes of broad spectrum anthelmintics, further stresses the need for new drugs active against gastro-intestinal nematodes. A novel chemical class of synthetic anthelmintics, the Amino-Acetonitrile Derivatives (AADs), was recently discovered and the drug candidate AAD-1566 (monepantel) was chosen for further development. Studies with Caenorhabditis elegans suggested that the AADs act via nicotinic acetylcholine receptors (nAChR) of the nematode-specific DEG-3 subfamily. Here we identify nAChR genes of the DEG-3 subfamily from H. contortus and investigate their role in AAD sensitivity. Using a novel in vitro selection procedure, mutant H. contortus populations of reduced sensitivity to AAD-1566 were obtained. Sequencing of full-length nAChR coding sequences from AAD-susceptible H. contortus and their AAD-1566-mutant progeny revealed 2 genes to be affected. In the gene monepantel-1 (Hco-mptl-1, formerly named Hc-acr-23H), a panel of mutations was observed exclusively in the AAD-mutant nematodes, including deletions at intron-exon boundaries that result in mis-spliced transcripts and premature stop codons. In the gene Hco-des-2H, the same 135 bp insertion in the 5' UTR created additional, out of frame start codons in 2 independent H. contortus AAD-mutants. Furthermore, the AAD mutants exhibited altered expression levels of the DEG-3 subfamily nAChR genes Hco-mptl-1, Hco-des-2H and Hco-deg-3H as quantified by real-time PCR. These results indicate that Hco-MPTL-1 and other nAChR subunits of the DEG-3 subfamily constitute a target for AAD action against H. contortus and that loss-of-function mutations in the corresponding genes may reduce the sensitivity to AADs.

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Forty Hampshire and 40 Suffolk ewes were allotted to one of four groups (VitA, VitE, VitA&E, Control) in a 2 x 2 factorial treatment arrangement to evaluate the effect of supplemental vitamin E (0 or 300 IU) and vitamin A (0 or 250,000 IU) on reproductive performance. Laparoscopy and ultrasonography were used to measure ovulation rate, embryonic loss, and fetal loss. Serum profiles of a-tocopherol (vitamin E) and retinol (vitamin A) also were monitored. There were no differences (P>.05) among treatment groups in any reproductive trait. Suffolk ewes exhibited a higher (P<.02) ovulation rate than Hampshire ewes, and yearling ewes incurred higher (P<.001) embryonic loss than other age groups, resulting in a lower (P<.001) litter size. Serum levels of a-tocopherol were higher (P<.05) for Hampshire than for Suffolk ewes and were lower (P<.001) in yearling ewes versus ewes two years of age and older. Serum levels of a-tocopherol declined (P<.01) throughout the study in VitA and Control ewes but remained unchanged in VitE and VitA&E ewes. Serum level of retinol remained unchanged in VitA ewes, whereas the level increased (P<.01) initially in VitE, VitA&E, and Control ewes before declining toward initial levels. Correlations were detected between ovulation rate and the change of pre-mating a-tocopherol serum level (r=-.29; P<.02), the change in pre-mating retinol serum level (r=-.50; P<.02) and the interval from vitamin A injection (r=-.60; P<.05). These data indicate significant influences of breed, age, and treatment on a-tocopherol and retinol serum levels in ewes and suggest that the timing of vitamin A administration may influence ovulation rate; however, vitamin supplementation, administered at random stages of the estrous cycle, was unable to alter flock reproductive performance.

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STUDY DESIGN Technical note and case series. OBJECTIVE To introduce an innovative minimal-invasive surgical procedure reducing surgery time and blood loss in management of U-shaped sacrum fractures. SUMMARY OF BACKGROUND Despite their seldom appearance, U-shaped fractures can cause severe neurological deficits and surgical management difficulties. According to the nature of the injury normally occurring in multi-injured patients after a fall from height, a jump, or road traffic accident, U-shaped fractures create a spinopelvic dissociation and hence are highly unstable. In the past, time-consuming open procedures like large posterior constructs or shortening osteotomies with or without decompression were the method of choice, sacrificing spinal mobility. Insufficient restoration of sacrococcygeal angle and pelvic incidence with conventional techniques may have adverse long-term effects in these patients. METHODS In a consecutive series of 3 patients, percutaneous reduction of the fracture with Schanz pins inserted in either the pedicles of L5 or the S1 body and the posterior superior iliac crest was achieved. The Schanz pins act as lever, allowing a good manipulation of the fracture. The reduction is secured by a temporary external fixator to permit optimal restoration of pelvic incidence and sacral kyphosis. Insertion of 2 transsacral screws allow fixation of the restored spinopelvic alignment. RESULTS Anatomic alignment of the sacrum was possible in each case. Surgery time ranged from 90 to 155 minutes and the blood loss was <50 mL in all 3 cases. Two patients had very good results in the long term regarding maintenance of pelvic incidence and sacrococcygeal angle. One patient with previous cauda equina decompression had loss of correction after 6 months. CONCLUSIONS Percutaneous reduction and transsacral screw fixation offers a less invasive method for treating U-shaped fractures. This can be advantageous in treatment of patients with multiple injuries.

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Hypernatremia is common in intensive care units. It has detrimental effects on various physiologic functions and was shown to be an independent risk factor for increased mortality in critically ill patients. Mechanisms of hypernatremia include sodium gain and/or loss of free water and can be discriminated by clinical assessment and urine electrolyte analysis. Because many critically ill patients have impaired levels of consciousness, their water balance can no longer be regulated by thirst and water uptake but is managed by the physician. Therefore, the intensivists should be very careful to provide the adequate sodium and water balance for them. Hypernatremia is treated by the administration of free water and/or diuretics, which promote renal excretion of sodium. The rate of correction is critical and must be adjusted to the rapidity of the development of hypernatremia.

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Band 4.1B is a cytoskeletal adaptor protein that regulates various cellular behavior; however, the mechanisms by which Band 4.1B contributes to intracellular signaling are unclear. This project addresses in vivo and in vitro functions for Band 4.1B in integrin-mediated cell adhesion and signaling. Band 4.1B has been shown to bind to β8 integrin, although cooperative functions of these two proteins have not been determined. Here, functional links between β8 integrin and Band 4.1B were investigated using gene knockout strategies. Ablation of β8 integrin and Band 4.1B genes resulted in impaired cardiac morphogenesis, leading to embryonic lethality by E11.5. These embryos displayed malformation of the outflow tract that was likely linked to abnormal regulation of cardiac neural crest migration. These data indicate the importance of cooperative signaling between β8 integrin and Band 4.1B in cardiac development. The involvement of Band 4.1B in integrin-mediated cell adhesion and signaling was further demonstrated by studying its functional roles in vitro. Band 4.1B is highly expressed in the brain, but its signaling in astrocytes is not understood. Here, Band 4.1B was shown to promote cell spreading likely by interacting with β1 integrin via its band 4.1, ezrin, radixin, and moesin (FERM) domain in cell adhesions. In astrocytes, both Band 4.1B and β1 integrin were expressed in cell-ECM contact sites during early cell spreading. Exogenous expression of Band 4.1B, especially its FERM domain, enhanced cell spreading on fibronectin, an ECM ligand for β1 integrin. However, the increased cell spreading was prohibited by blocking β1 integrin. These findings suggest that Band 4.1B is crucial for early adhesion assembly and/or signaling that are mediated by β1 integrin. Collectively, this study was the first to establish Band 4.1B as a modulator of integrin-mediated adhesion and signaling.

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CD4+ T helper (Th) lymphocytes are vital for integrating immune responses by orchestrating the function of other immune cell types. Naïve Th cells can differentiate into different effector subsets that are characterized by their cytokine profile and immune regulatory functions. These subsets include Th1, Th2, Th17, natural and inducible regulatory T cells (nTreg and iTreg respectively), among others. We focused our investigation on two Th lineages, Th17 and regulatory T cells, with opposing functions in the immune system. These subsets have been suggested to be reciprocally regulated since they both require TGF-b for their development. We investigated the role of the Treg-associated master transcription factor Foxp3, and found that Foxp3 inhibits Th17 cell generation by preventing the transcriptional activity of the two main Th17-specific transcription factors, nuclear orphan receptors RORa and RORgt. At the molecular level, we identified two different functional domains in Foxp3 required for such inhibition: the LQALL sequence in exon 2 and the TIP60/HDAC7 binding domain. These domains could be crucial to either prevent the association of the nuclear receptors to coactivators or to recruit histone deacetylases to RORa- or RORgt-target genes. Since TGF-b is a common cytokine required for the commitment towards both Th lineages, we determined the role of the TGF-b-dependent signaling pathway in the generation of each subset. By using mice with deficiencies in signaling molecules downstream of TGF-b, we found that while Smad2, Smad3 and Smad4 are required for the generation of iTreg cells, only Smad2 is indispensable for the induction of IL-17-producing cells, suggesting that TGF-b induces these T helper lineages through differential signaling pathways. Thus, our findings describe novel transcriptional regulatory mechanisms that control the generation of two T helper lineages with opposing functions. These findings could provide novel therapeutic targets to treat diseases where the balance of these T cells is dysregulated, such as in autoimmunity, chronic infectious diseases and cancer.

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Purpose: To evaluate the clinical impact of the Varian Exact Couch on dose and volume coverage to targets and critical structures and tumor control probability (TCP) for 6-MV IMRT and Arc Therapy. Methods: Five clinical prostate patients were planned with both, 6-MV 8-field IMRT and 6-MV 2-field RapidArc using the Eclipse treatment planning system (TPS). These plans neglected treatment couch attenuation, as is standard clinical practice. Dose distributions were then recalculated in Eclipse with the inclusion of the Varian Exact Couch (imaging couch top) and the rails in varying configurations. The changes in dose and coverage were evaluated using the DVHs from each plan iteration. We used a tumor control probability (TCP) model to calculate losses in tumor control resulting from not accounting for the couch top and rails. We also verified dose measurements in a phantom. Results: Failure to account for the treatment couch and rails resulted in clinically unacceptable dose and volume coverage losses to the target for both IMRT and RapidArc. The couch caused average dose losses (relative to plans that ignored the couch) to the prostate of 4.2% and 2.0% for IMRT with the rails out and in, respectively, and 3.2% and 2.9% for RapidArc with the rails out and in, respectively. On average, the percentage of the target covered by the prescribed dose dropped to 35% and 84% for IMRT (rails out and in, respectively) and to 18% and 17% for RapidArc (rails out and in, respectively). The TCP was also reduced by as much as 10.5% (6.3% on average). Dose and volume coverage losses for IMRT plans were primarily due to the rails, while the imaging couch top contributed most to losses for RapidArc. Both the couch top and rails contribute to dose and coverage losses that can render plans clinically unacceptable. A follow-up study we performed found that the less attenuating unipanel mesh couch top available with the Varian Exact couch does not cause a clinically impactful loss of dose or coverage for IMRT but still causes an unacceptable loss for RapidArc. Conclusions: Both the imaging couch top and rails contribute to dose and coverage loss to a degree that, if included, would prevent the plan from meeting clinical planning criteria. Therefore, the imaging and mesh couch tops and rails should be accounted for in Arc Therapy and the imaging couch and rails only in IMRT treatment planning.

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Septic shock is characterized by increased vascular permeability and hypotension despite increased cardiac output. Numerous vasoactive cytokines are upregulated during sepsis, including angiopoietin 2 (ANG2), which increases vascular permeability. Here we report that mice engineered to inducibly overexpress ANG2 in the endothelium developed sepsis-like hemodynamic alterations, including systemic hypotension, increased cardiac output, and dilatory cardiomyopathy. Conversely, mice with cardiomyocyte-restricted ANG2 overexpression failed to develop hemodynamic alterations. Interestingly, the hemodynamic alterations associated with endothelial-specific overexpression of ANG2 and the loss of capillary-associated pericytes were reversed by intravenous injections of adeno-associated viruses (AAVs) transducing cDNA for angiopoietin 1, a TIE2 ligand that antagonizes ANG2, or AAVs encoding PDGFB, a chemoattractant for pericytes. To confirm the role of ANG2 in sepsis, we i.p. injected LPS into C57BL/6J mice, which rapidly developed hypotension, acute pericyte loss, and increased vascular permeability. Importantly, ANG2 antibody treatment attenuated LPS-induced hemodynamic alterations and reduced the mortality rate at 36 hours from 95% to 61%. These data indicate that ANG2-mediated microvascular disintegration contributes to septic shock and that inhibition of the ANG2/TIE2 interaction during sepsis is a potential therapeutic target.

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The cytochrome P450 monooxygenase system consists of NADPH- cytochrome P450 reductase (P450 reductase) and cytochromes P450, which can catalyze the oxidation of a wide variety of endogenous and exogenous compounds, including steroid hormones, fatty acids, drugs, and pollutants. The functions of this system are as diverse as the substrates. P450 reductase transfers reducing equivalents from NADPH to P450, which in turn catalyzes metabolic reactions. This enzyme system has the highest level of activity in the liver. It is also present in other tissues, including brain. The functions of this enzyme system in brain seem to include: neurotransmission, neuroendocrinology, developmental and behavioral modulation, regulation of intracellular levels of cholesterol, and potential neurotoxicity.^ In this study, we have set up the rat glioma C6 cell line as an in vitro model system to examine the expression, induction, and tissue-specific regulation of P450s and P450 reductase. Rat glioma C6 cells were treated with P450 inducers phenobarbital (PB) or benzo(a)anthracene (BA). The presence of P450 reductase and of cytochrome P450 1A1, 1A2, 2A1, 2B1/2, 2C7, 2D1-5 and 2E1 was detected by reverse transcription followed by polymerase chain reaction (RT-PCR) and confirmed by restriction digestion. The induction of P450 1A1 and 2B1/2 and P450 reductase was quantified using competitive PCR. Ten- and five-fold inductions of P450 1A and 2B mRNA after BA or PB treatments, respectively, were detected. Western blot analysis of microsomal preparations of glioma C6 cells demonstrated the presence of P450 1A, 2B and P450 reductase at the protein level. ELISAs showed that BA and PB induce P450 1A and 2B proteins 7.3- and 13.5-fold, respectively. Microsomes prepared from rat glioma C6 cells showed cytochrome P450 CO difference spectra with absorption at or near 450 nm. Microsomes prepared from rat glioma C6 cells demonstrated much higher levels of ethoxyresorufin O-deethylase (EROD) and pentoxyresorufin O-dealkylase (PROD) activity, when treated with BA or PB, respectively. These experiments provide further evidence that the rat glioma C6 cell line contains an active cytochrome P450 monooxygenase system which can be induced by P450 inducers. The mRNAs of P450 1A1 and 2B1/2 can not bind to the oligo(dT) column efficiently, indicating they have very short poly(A) tails. This finding leads us to study the tissue specific regulation of P450s at post-transcriptional level. The half lives of P450 1A1 and 2B1/2 mRNA in glioma C6 cells are only 1/10 and 1/3 of that in liver. This may partly contribute to the low expression level of P450s in glial cells. The induction of P450s by BA or PB did not change their mRNA half lives, indicating the induction may be due to transcriptional regulation. In summary of this study, we believe the presence of the cytochrome P450 monooxygenase system in glial cells of the brain may be important in chemotherapy and carcinogenesis of brain tumors. ^

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Cognitive Remediation approaches have proven to be effective in enhancing cognitive functions and psychosocial outcomes in multi-episode schizophrenia patients. However, there is a paucity of studies evaluating Cognitive Remediation in first-episode psychosis patients and in those symptomatically at-risk for psychosis. This is despite the growing evidence that impairments in neuro- and social-cognitive functions are already present in early psychosis and even in at-risk mental states and are important predictors of poor outcome, including transition to psychosis. Moreover, Cognitive Remediation applied at younger ages and at earlier stages of schizophrenia yielded greater cognitive and functional gains. Therefore, Cognitive Remediation may be especially appropriate for early intervention. Against this background, we will review and discuss the efficacy of current Cognitive Remediation approaches in early psychosis and in at-risk mental states. Furthermore, we will present novel interventions that are tailored to the specific needs and developmental tasks of patients at-risk for psychosis and aim at improving social and self-referential cognitions as well as interpersonal skills