A host–guest approach for determining drug–DNA interactions: an example using netropsin

Netropsin is a well-characterized DNA minor groove binding compound that serves as a model for the study of drug–DNA interactions. Our laboratory has developed a novel host–guest approach to study drug–DNA interactions in which the host, the N-terminal fragment of Moloney murine leukemia virus reverse transcriptase (MMLV RT) is co-crystallized with a DNA oligonucleotide guest in the presence and absence of drug. We have co-crystallized netropsin with the RT fragment bound to the symmetric 16mer d(CTTAATTCGAATTAAG)(2) and determined the structure of the complex at 1.85 Å. In contrast to previously reported netropsin–DNA structures, our oligonucleotide contains two AATT sites that bind netropsin with flanking 5′ and 3′ sequences that are not symmetric. The asymmetric unit of the RT fragment–DNA–netropsin crystals contains one protein molecule and one-half of the 16mer with one netropsin molecule bound. The guanidinium moiety of netropsin binds in a narrow part of the minor groove, while the amidinium is bound in the widest region within the site. We compare this structure to other Class I netropsin–DNA structures and find that the asymmetry of minor groove widths in the AATT site contributes to the orientation of netropsin within the groove while hydrogen bonding patterns vary in the different structures

Hormonal Contraception Use is Common Among Patients with Inflammatory Bowel Diseases and an Elevated Risk of Deep Vein Thrombosis:

Persons with inflammatory bowel disease (IBD) have an increased risk of venous thromboembolism (VTE). We sought to examine whether self-report of hormonal contraception (HC), as a proxy for exposure to estrogen-based contraception, was less common for women with multiple risk factors for VTE

Cytomegalovirus viral load in the colon and risk of colectomy in hospitalized patients with inflammatory bowel diseases

To the Editor: We read with interest the article of Lee et al1 describing the risk factors for adverse outcomes in hospitalized patients with ulcerative colitis (UC) with concurrent cytomegalovirus (CMV) colitis. CMV reactivation and resolution can be spontaneous in patients with UC regardless of antiviral therapy; however, inconsistencies between CMV detection methods of various studies and criteria for defining CMV positivity may be leading to these disparate findings.2,3 In the study by Lee et al, CMV colitis was defined by the presence of 1 or more inclusion bodies on hematoxylin and eosin staining or CMV immunohistochemistry on colonic biopsies. The most accurate approach for detection of clinically significant CMV infection has not been firmly established and guidelines differ in their recommendations.3,4 A recent study using quantitative colonic PCR in consecutive patients with UC undergoing endoscopy in the setting of a moderate to severe flare demonstrated a correlation between higher viral load and resistance to immunosuppressive therapy with significant differences found when using a cutoff viral load of .250 per milligram tissue.

Prevalence of a Gluten-free Diet and Improvement of Clinical Symptoms in Patients with Inflammatory Bowel Diseases:

Background—Maintaining a gluten free diet (GFD) without an underlying diagnosis of celiac disease has enjoyed widespread acceptance in the USA. Methods—We performed a cross-sectional study utilizing a GFD questionnaire in 1647 patients with inflammatory bowel diseases (IBD) participating in the CCFA Partners longitudinal, Internet-based cohort. Results—A diagnosis of celiac disease (CD) and non-celiac gluten sensitivity (NCGS) were reported by 10 (0.6%) and 81 (4.9%) respondents, respectively. Three hundred fourteen (19.1%) participants reported having previously tried a GFD and 135 (8.2%) reported current use of GFD. Overall 65.6% of all patients, who attempted a GFD described an improvement of their GI-symptoms and 38.3% reported fewer or less severe IBD flares. In patients currently attempting a GFD, excellent adherence was associated with significant improvement of fatigue (p<0.03). Conclusion—In this large group of patients with IBD, a substantial number had attempted a GFD, of whom the majority had some form of improvement in GI-symptoms. Testing a GFD in clinical practice in patients with significant intestinal symptoms, which are not solely explained by the degree of intestinal inflammation, has the potential to be a safe and highly efficient therapeutic approach. Further prospective studies into mechanisms of gluten sensitivity in IBD are warranted

Semi-automated high-throughput fluorescent intercalator displacement-based discovery of cytotoxic DNA binding agents from a large compound library

High-throughput fluorescent intercalator displacement (HT–FID) was adapted to the semi-automated screening of a commercial compound library containing 60,000 molecules resulting in the discovery of cytotoxic DNA-targeted agents. Although commercial libraries are routinely screened in drug discovery efforts, the DNA binding potential of the compounds they contain has largely been overlooked. HT–FID led to the rapid identification of a number of compounds for which DNA binding properties were validated through demonstration of concentration-dependent DNA binding and increased thermal melting of A/T- or G/C-rich DNA sequences. Selected compounds were assayed further for cell proliferation inhibition in glioblastoma cells. Seven distinct compounds emerged from this screening procedure that represent structures unknown previously to be capable of targeting DNA leading to cell death. These agents may represent structures worthy of further modification to optimally explore their potential as cytotoxic anti-cancer agents. In addition, the general screening strategy described may find broader impact toward the rapid discovery of DNA targeted agents with biological activity

Avoidance of Fiber Is Associated With Greater Risk of Crohn’s Disease Flare in a 6-Month Period

Chronic inflammatory bowel diseases (IBDs) have been associated with an abnormal mucosal response to the gastrointestinal microbiota. Although dietary fiber affects the gastrointestinal microbiota, there is limited information on the role of fiber on IBD activity. We investigated factors associated with fiber consumption and whether it was associated with flares in patients with IBD

Role of Nonsteroidal Anti-Inflammatory Drugs in Exacerbations of Inflammatory Bowel Disease

To determine the role of NSAIDs in activation of IBD

Use of Biologics in Pouchitis: A Systematic Review

Data about the effectiveness of biologics, including anti-TNF therapy and anti-integrin strategies, in antibiotic refractory pouchitis or Crohn’s disease-associated pouch complications are sparse. We performed a systematic review of the literature in Medline and Web of Science. All English language publications and meeting abstracts describing patients with pouchitis treated with anti-TNF or anti-integrin therapies were included. We identified a total of 17 papers and 2 abstracts, most of these retrospective case series, including a total of 192 patients treated either with infliximab (IFX; n=140) or adalimumab (ADA; n=52). No reports were found for anti-integrin therapies or other anti-TNF agents such as certolizumab pegol or golimumab. Due to the heterogeneity of the studies, small numbers of patients, differing co-treatments and subjective outcome definitions, the exact efficacy of these biologic therapies cannot be assessed in a combined fashion. Overall IFX appears to have good clinical effectiveness in selected patients achieving up to 80% short and around 50% long-term response, whereas the few data available for ADA are not sufficient to draw valid conclusions. Larger prospectively collected multi-center data with clearly defined inclusion criteria and outcomes are necessary to better define the clinical value of anti-TNF therapy in patients with antibiotic refractory pouchitis or Crohn’s-like complications of the pouch

Methotrexate: Underused and Ignored?

For greater than a decade, methotrexate has been known to be an effective therapeutic agent in the treatment of steroid dependent active Crohn's disease. However, international data on medication utilization suggest that this drug is rarely used in clinical practice for an indication of Crohn's disease. This review investigates the potential reasons for the underuse of methotrexate in patients with inflammatory bowel diseases

Nonmelanoma skin cancer in inflammatory bowel disease: A review

At least 1 million new cases of non-melanoma skin cancer (NMSC) are diagnosed in the United States each year, and the incidence is increasing. A higher incidence of non-melanoma skin cancer (NMSC) in organ transplant recipients on immunosuppression has been documented for some time, and recent studies indicate that patients with inflammatory bowel disease (IBD), particularly those treated with immunosuppressive medications, might also be at higher risk for this condition. In this review, we summarize recent data evaluating the associations between immunomodulators, anti-tumor necrosis factor-α (anti-TNF) biologic agents and NMSC in patients with IBD and other autoimmune conditions such as rheumatoid arthritis (RA). We also offer recommendations for prevention of NMSC in these populations