MOTIVATION: Many have observed a nonlinear relationship between the signal intensity and the transcript abundance in microarray data. The first step in analyzing the data is to normalize it properly, and this should include a correction for the nonlinearity. The commonly used linear normalization schemes do not address this problem. RESULTS: Nonlinearity is present in both cDNA and oligonucleotide arrays, but we concentrate on the latter in this paper. Across a set of chips, we identify those genes whose within-chip ranks are relatively constant compared to other genes of similar intensity. For each gene, we compute the sum of the squares of the differences in its within-chip ranks between every pair of chips as our statistic and we select a small fraction of the genes with the minimal changes in ranks at each intensity level. These genes are most likely to be non-differentially expressed and are subsequently used in the normalization procedure. This method is a generalization of the rank-invariant normalization (Li and Wong, 2001), using all available chips rather than two at a time to gather more information, while using the chip that is least likely to be affected by nonlinear effects as the reference chip. The assumption in our method is that there are at least a small number of nondifferentially expressed genes across the intensity range. The normalized expression values can be substantially different from the unnormalized values and may result in altered down-stream analysis.
DNA, Complementary ; Gene Expression ; Generalization (Psychology) ; Motivation ; Oligonucleotide Array Sequence Analysis*

The purpose of this research was to investigate functional studies by which the hiatal hernia (HH) may be relevant to a reflux esophagitis (RE). Group I consisted of healthy controls who were endoscopically normal (n = 21). Group II consisted of patients with hiatal hernia but no reflux esophagitis (n = 8). Group III had patients with hiatal hernia with reflux esophagitis (n = 9). Group IV had patients with reflux esophagitis but no hiatal hernia (n = 16). Esophageal manometry, ambulatory 24 hour intraesophageal pH monitoring, acid clearance test, and gastric emptying scan were performed in each of the patients. The contraction amplitude at 3 cm above the lower esophageal sphincter did not differ significantly among the four groups, but the mean lower esophageal sphincter pressure was significantly decreased in group II. The DeMeester score in ambulatory 24 hour intraesophageal pH monitoring was significantly higher in group III compared with the controls. No significant difference among the groups was found with respect to acid clearance. Total and proximal gastric emptying times (T1/2) were significantly delayed in group III. We found that hiatal hernia combined with delayed gastric emptying may bear a relationship to the multifactorial origins of reflux esophagitis, and we suggest a rationale for using prokinetic agents as the therapeutic regimen in patients with HH complicated by RE.
Adult ; Esophagitis, Peptic/*etiology/metabolism/physiopathology ; Esophagogastric Junction/physiopathology ; Esophagus/metabolism ; Female ; Hernia, Hiatal/*complications/physiopathology ; Human ; Hydrogen-Ion Concentration ; Male ; Manometry ; Pressure

Accurate detection of homologous recombination deficiency (HRD) in cancer patients is paramount in clinical applications, as HRD confers sensitivity to poly(ADP-ribose) polymerase (PARP) inhibitors. With the advances in genome sequencing technology, mutational profiling on a genome-wide scale has become readily accessible, and our knowledge of the genomic consequences of HRD has been greatly expanded and refined. Here, we review the recent advances in HRD detection methods. We examine the copy number and structural alterations that often accompany the genome instability that results from HRD, describe the advantages of mutational signature-based methods that do not rely on specific gene mutations, and review some of the existing algorithms used for HRD detection. We also discuss the choice of sequencing platforms (panel, exome, or whole-genome) and catalog the HRD detection assays used in key PARP inhibitor trials.

Accurate detection of homologous recombination deficiency (HRD) in cancer patients is paramount in clinical applications, as HRD confers sensitivity to poly(ADP-ribose) polymerase (PARP) inhibitors. With the advances in genome sequencing technology, mutational profiling on a genome-wide scale has become readily accessible, and our knowledge of the genomic consequences of HRD has been greatly expanded and refined. Here, we review the recent advances in HRD detection methods. We examine the copy number and structural alterations that often accompany the genome instability that results from HRD, describe the advantages of mutational signature-based methods that do not rely on specific gene mutations, and review some of the existing algorithms used for HRD detection. We also discuss the choice of sequencing platforms (panel, exome, or whole-genome) and catalog the HRD detection assays used in key PARP inhibitor trials.

Accurate detection of homologous recombination deficiency (HRD) in cancer patients is paramount in clinical applications, as HRD confers sensitivity to poly(ADP-ribose) polymerase (PARP) inhibitors. With the advances in genome sequencing technology, mutational profiling on a genome-wide scale has become readily accessible, and our knowledge of the genomic consequences of HRD has been greatly expanded and refined. Here, we review the recent advances in HRD detection methods. We examine the copy number and structural alterations that often accompany the genome instability that results from HRD, describe the advantages of mutational signature-based methods that do not rely on specific gene mutations, and review some of the existing algorithms used for HRD detection. We also discuss the choice of sequencing platforms (panel, exome, or whole-genome) and catalog the HRD detection assays used in key PARP inhibitor trials.

Accurate detection of homologous recombination deficiency (HRD) in cancer patients is paramount in clinical applications, as HRD confers sensitivity to poly(ADP-ribose) polymerase (PARP) inhibitors. With the advances in genome sequencing technology, mutational profiling on a genome-wide scale has become readily accessible, and our knowledge of the genomic consequences of HRD has been greatly expanded and refined. Here, we review the recent advances in HRD detection methods. We examine the copy number and structural alterations that often accompany the genome instability that results from HRD, describe the advantages of mutational signature-based methods that do not rely on specific gene mutations, and review some of the existing algorithms used for HRD detection. We also discuss the choice of sequencing platforms (panel, exome, or whole-genome) and catalog the HRD detection assays used in key PARP inhibitor trials.

Background/Aims: Insomnia is common in people with chronic medical conditions, such as inflammatory bowel disease (IBD), and is readily treatable through cognitive behavioral therapy for insomnia. This study aimed to describe the associations with insomnia in people with IBD and its relationship to IBD-related disability. Methods: An online questionnaire was administered through 3 tertiary IBD centers, social media, and Crohn’s Colitis Australia. The questionnaire included the Insomnia Severity Index (ISI), a validated assessment of insomnia. Measures of anxiety, depression, physical activity, and disability were also included. IBD activity was assessed using validated patient reported scores. A multivariate model was constructed for clinically significant insomnia and ISI scores. Subpopulations of Crohn’s disease and ulcerative colitis were considered. Results: In a cohort of 670 respondents the median age was 41 years (range, 32–70 years), with the majority female (78.4%), the majority had Crohn’s disease (57.3%). Increasingly severe disability was associated with worse insomnia score. Clinically significant insomnia was associated with clinically active IBD, abdominal pain, anxiety, and depression, in a multivariate model. In an ulcerative colitis population, Simple Clinical Colitis Activity Index components of general well-being and urgency were associated with worse ISI score in a model including depression and anxiety. In those with Crohn’s disease, the multivariate model included Harvey Bradshaw Index score in addition to depression and anxiety. Conclusions Insomnia is common in people with IBD and is associated with increased disability. Abdominal pain and mental health conditions should prompt consideration for screening for insomnia and referral for cognitive behavioral therapy for insomnia.

BACKGROUND/AIMS: Irritable bowel syndrome (IBS) is a multifaceted disorder that afflicts millions of individuals worldwide. IBS is currently diagnosed based on the presence/duration of symptoms and systematic exclusion of other conditions. A more direct manner to identify IBS is needed to reduce healthcare costs and the time required for accurate diagnosis. The overarching objective of this work is to identify gene expression-based biological signatures and biomarkers of IBS. METHODS: Gene transcripts from 24 tissue biopsy samples were hybridized to microarrays for gene expression profiling. A combination of multiple statistical analyses was utilized to narrow the raw microarray data to the top 200 differentially expressed genes between IBS versus control subjects. In addition, quantitative polymerase chain reaction was employed for validation of the DNA microarray data. Gene ontology/pathway enrichment analysis was performed to investigate gene expression patterns in biochemical pathways. Finally, since vitamin D has been shown to modulate serotonin production in some models, the relationship between serum vitamin D and IBS was investigated via 25-hydroxyvitamin D (25[OH]D) chemiluminescence immunoassay. RESULTS: A total of 858 genetic features were identified with differential expression levels between IBS and asymptomatic populations. Gene ontology enrichment analysis revealed the serotonergic pathway as most prevalent among the differentially expressed genes. Further analysis via real-time polymerase chain reaction suggested that IBS patient-derived RNA exhibited lower levels of tryptophan hydroxylase-1 expression, the enzyme that catalyzes the rate-limiting step in serotonin biosynthesis. Finally, mean values for 25(OH)D were lower in IBS patients relative to non-IBS controls. CONCLUSIONS: Values for serum 25(OH)D concentrations exhibited a trend towards lower vitamin D levels within the IBS cohort. In addition, the expression of select IBS genetic biomarkers, including tryptophan hydroxylase 1, was modulated by vitamin D. Strikingly, the direction of gene regulation elicited by vitamin D in colonic cells is “opposite” to the gene expression profile observed in IBS patients, suggesting that vitamin D may help “reverse” the pathological direction of biomarker gene expression in IBS. Thus, our results intimate that IBS pathogenesis and pathophysiology may involve dysregulated serotonin production and/or vitamin D insufficiency.
Biomarkers ; Biopsy ; Cohort Studies ; Colon ; Diagnosis ; Gene Expression Profiling ; Gene Expression ; Gene Ontology ; Health Care Costs ; Humans ; Immunoassay ; Irritable Bowel Syndrome ; Luminescence ; Oligonucleotide Array Sequence Analysis ; Polymerase Chain Reaction ; Real-Time Polymerase Chain Reaction ; RNA ; Serotonin ; Transcriptome ; Tryptophan ; Tryptophan Hydroxylase ; Vitamin D ; Vitamins