48 research outputs found

    Role of germline aberrations affecting CTNNA1, MAP3K6 and MYD88 in gastric cancer susceptibility

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    Background In approximately 10% of all gastric cancer (GC) cases, a heritable cause is suspected. A subset of these cases have a causative germline CDH1 mutation; however, in most cases the cause remains unknown. Our objective was to assess to what extent these remaining cases may be explained by germline mutations in the novel candidate GC predisposing genes CTNNA1, MAP3K6 or MYD88. Methods We sequenced a large cohort of unexplained young and/or familial patients with GC (n=286) without a CDH1germline mutation for germline variants affecting CTNNA1, MAP3K6 and MYD88 using a targeted next-generation sequencing approach based on single-molecule molecular inversion probes. Results Predicted deleterious germline variants were not encountered in MYD88, but recurrently observed in CTNNA1 (n=2) and MAP3K6 (n=3) in our cohort of patients with GC. In contrast to deleterious variants in CTNNA1, deleterious variants in MAP3K6 also occur frequently in the general population. Conclusions Based on our results MAP3K6 should no longer be considered a GC predisposition gene, whereas deleterious CTNNA1 variants are confirmed as an infrequent cause of GC susceptibility. Biallelic MYD88 germline mutations are at most a very rare cause of GC susceptibility as no additional cases were identified.This study was funded by KWF Kankerbestrijding (grant number KUN2013-5876, RSvdP)

    Role of germline aberrations affecting CTNNA1, MAP3K6 and MYD88 in gastric cancer susceptibility

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    Background: In approximately 10% of all gastric cancer (GC) cases, a heritable cause is suspected. A subset of these cases have a causative germline CDH1 mutation; however, in most cases the cause remains unknown. Our objective was to assess to what extent these remaining cases may be explained by germline mutations in the novel candidate GC predisposing genes CTNNA1, MAP3K6 or MYD88. Methods: We sequenced a large cohort of unexplained young and/or familial patients with GC (n=286) without a CDH1germline mutation for germline variants affecting CTNNA1, MAP3K6 and MYD88 using a targeted next-generation sequencing approach based on single-molecule molecular inversion probes. Results: Predicted deleterious germline variants were not encountered in MYD88, but recurrently observed in CTNNA1 (n=2) and MAP3K6 (n=3) in our cohort of patients with GC. In contrast to deleterious variants in CTNNA1, deleterious variants in MAP3K6 also occur frequently in the general population. Conclusions: Based on our results MAP3K6 should no longer be considered a GC predisposition gene, whereas deleterious CTNNA1 variants are confirmed as an infrequent cause of GC susceptibility. Biallelic MYD88 germline mutations are at most a very rare cause of GC susceptibility as no additional cases were identified

    The adaptive significance of chromosomal inversion polymorphisms in Drosophila melanogaster

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    Chromosomal inversions, structural mutations that reverse a segment of a chromosome, cause suppression of recombination in the heterozygous state. Several studies have shown that inversion polymorphisms can form clines or fluctuate predictably in frequency over seasonal time spans. These observations prompted the hypothesis that chromosomal rearrangements might be subject to spatially and/or temporally varying selection. Here, we review what has been learned about the adaptive significance of inversion polymorphisms in the vinegar fly Drosophila melanogaster, the species in which they were first discovered by Sturtevant in 1917. A large body of work provides compelling evidence that several inversions in this system are adaptive; however, the precise selective mechanisms that maintain them polymorphic in natural populations remain poorly understood. Recent advances in population genomics, modelling and functional genetics promise to greatly improve our understanding of this long‐standing and fundamental problem in the near future

    Deficient modulation of pain by a positive emotional context in fibromyalgia patients

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    This study aimed to investigate the modulating effects of emotional context on pain perception in 16 patients with fibromyalgia syndrome (FMS) and 16 healthy control (HC) subjects. An infrared laser was used to apply individually adapted painful stimuli to the dorsum of the left hand. The emotional background of the painful stimuli was modulated by concurrent presentations of negative, neutral, and positive picture stimuli selected from the International Affective Picture System. As control conditions, painful stimuli and the pictures were also presented by themselves. During each of the 5 laser-picture trials, subjects received 10 painful stimuli and were asked to rate the average intensity and unpleasantness of the experienced pain. Functional magnetic resonance images were obtained, using a T2∗ sensitive echo planar sequence. HC subjects showed a linear increase in pain intensity and unpleasantness ratings when painful stimuli were presented during positive, neutral, and negative pictures. In contrast, FMS patients showed a quadratic trend for pain intensity ratings indicating a lack of pain reduction by the positive pictures. In addition, the FMS patients showed less activation in secondary somatosensory cortex, insula, orbitofrontal cortex, and anterior cingulate cortex during the positive picture pain trials. Our results suggest that fibromyalgia patients are less efficient in modulating pain by positive affect and may benefit less from appetitive events than healthy control subjects

    The influence of experience and training in a group of novice observers : A jackknife alternative free-response receiver operating characteristic analysis

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    Purpose: The study evaluates the pre- and post-training lesion localisation ability of a group of novice observers. Parallels are drawn with the performance of inexperienced radiographers taking part in preliminary clinical evaluation (PCE) and ‘red-dot’ systems, operating within radiography practice. Materials and methods: Thirty-four novice observers searched 92 images for simulated lesions. Pretraining and post-training evaluations were completed following the free-response the receiver operating characteristic (FROC) method. Training consisted of observer performance methodology, the characteristics of the simulated lesions and information on lesion frequency. Jackknife alternative FROC (JAFROC) and highest rating inferred ROC analyses were performed to evaluate performance difference on lesion-based and case-based decisions. The significance level of the test was set at 0.05 to control the probability of Type I error. Results: JAFROC analysis (F(3,33) ¼ 26.34, p < 0.0001) and highest-rating inferred ROC analysis (F(3,33) ¼ 10.65, p ¼ 0.0026) revealed a statistically significant difference in lesion detection performance. The JAFROC figure-of-merit was 0.563 (95% CI 0.512,0.614) pre-training and 0.677 (95% CI 0.639,0.715) post-training. Highest rating inferred ROC figure-of-merit was 0.728 (95% CI 0.701,0.755) pre-training and 0.772 (95% CI 0.750,0.793) post-training. Conclusions: This study has demonstrated that novice observer performance can improve significantly. This study design may have relevance in the assessment of inexperienced radiographers taking part in PCE or commenting scheme for trauma
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