Impact of early thiopurines on surgery in 2770 children and young people diagnosed with inflammatory bowel disease: a national population-based study

BACKGROUND

The role of early thiopurine treatment in inflammatory bowel disease (IBD) is unproven.

AIM

To quantify the impact of timing and duration of thiopurines on the risk of first surgery in children and young people with IBD using a population-based cohort.

METHODS

We constructed an incident cohort of children and young people aged <25 years, diagnosed with Crohn's disease (CD) or ulcerative colitis (UC) from 1990 to 2009. We used Cox proportional hazards modelling to determine the impact of early thiopurine use, commenced within a year of diagnosis on risk of first surgery.

RESULTS

We identified 1595 and 1175 incident cases of CD and UC respectively with a mean length of follow-up of 4.3 years/person. There were 216 (13.5%) and 73 (6.2%) surgeries for CD and UC patients between 1990 and 2009 respectively. In CD among thiopurine users, the absolute risk of surgery at 5 years for early thiopurine use vs. late was 15.3% (95% CI: 10.5-22.1) vs. 22.1% (95% CI: 18.1-26.9) respectively. After adjustment, the early use of thiopurines was associated with a reduction in risk of first surgery of 39% (HR 0.61, 95% CI: 0.41-0.91) over the 20-year study period. In UC, early thiopurine use offered no additional benefit.

CONCLUSIONS

In Crohn's disease, early treatment with thiopurines in children and young people is associated with an appreciable reduction in the risk of surgery, but early treatment does not reduce surgical risk in UC.

Note: Design and development of wireless controlled aerosol sampling network for large scale aerosol dispersion experiments

Wireless based custom built aerosol sampling network is designed, developed, and implemented for environmental aerosol sampling. These aerosol sampling systems are used in field measurement campaign, in which sodium aerosol dispersion experiments have been conducted as a part of environmental impact studies related to sodium cooled fast reactor. The sampling network contains 40 aerosol sampling units and each contains custom built sampling head and the wireless control networking designed with Programmable System on Chip (PSoC™) and Xbee Pro RF modules. The base station control is designed using graphical programming language LabView. The sampling network is programmed to operate in a preset time and the running status of the samplers in the network is visualized from the base station. The system is developed in such a way that it can be used for any other environment sampling system deployed in wide area and uneven terrain where manual operation is difficult due to the requirement of simultaneous operation and status logging.

Interaction of collagen like peptides with gold nanosurfaces: a molecular dynamics investigation

In this study, an attempt has been made to understand the interaction between collagen like peptides (CPs) with a gold nanosurface (AuNS) using a classical molecular dynamics simulation.

The impact of timing and duration of thiopurine treatment on colectomy in ulcerative colitis: a national population-based study of incident cases between 1989-2009

BACKGROUND

The role of thiopurines in altering the risk of colectomy in ulcerative colitis (UC) remains unclear.

AIMS

To examine predictors of colectomy in UC and determine the impact of thiopurines on the risk of colectomy.

METHODS

We constructed a population-based cohort of incident cases of UC in the United Kingdom between 1989 and 2009. We determined trends in thiopurine usage and colectomy for three defined cohorts: era 1 (1989-1995), era 2 (1996-2002), era 3 (2003-2009). We used Cox regression to determine predictors of colectomy and quantified the impact of duration and timing of thiopurine use on the risk of colectomy.

RESULTS

We identified 8673 incident cases of UC. 5-year colectomy rates increased from 4.2%, 5.1% to 6.9% (P = 0.001) for era 1, era 2 and era 3, respectively, despite increasing thiopurine use. This was not significant after adjustment for predictors of colectomy (P = 0.06). There was a higher risk of colectomy in men (HR 1.44, 95% CI: 1.19-1.73), those diagnosed at an early age (HR 1.35, 95% CI: 1.04-1.75; 16-24 vs. 25-64) and early steroid users (HR 1.94, 95% CI: 1.59-2.37). 5-ASA users were less likely to require a colectomy (HR 0.35, 95% CI: 0.28-0.44). Amongst thiopurine users, those treated for greater than 12 months had a 71% reduction in risk of colectomy (HR 0.29, 95% CI: 0.21-0.40). Early thiopurines offered no additional benefit.

CONCLUSIONS

Thiopurine exposure for greater than 12 months reduces the likelihood of colectomy by 71%. Young men and those requiring steroids within 3 months of diagnosis are at greatest risk of colectomy, and most likely to benefit from sustained thiopurine use.

Immune response to tissue-restricted self-antigens induces airway inflammation and fibrosis following murine lung transplantation

Immune responses against lung-associated self-antigens (self-Ags) are hypothesized to play a role in the development of chronic lung graft rejection. We determined whether immune responses to lung self-Ags, K-alpha-1-tubulin (Kα1T) and Collagen V (Col-V) in the absence of alloimmunity, could promote airway inflammation and fibrosis. Following syngeneic murine orthotopic lung transplantation (LTx) we administered antibodies (Abs) to either Kα1T or Col-V or in combination to both of these self-Ags. As compared to recipients of isotype control Abs, Kα1T Abs and/or Col-V Abs-treated recipients had marked lung graft cellular infiltration and bronchiolar fibrosis. This inflammation was also associated the accumulation of Kα1T and Col-V-specific interferon-γ+ and IL-17+ T cells. Notably, the administration of Abs to Kα1T led to cellular and humoral immune responses to Col-V prior to development of fibrosis, and vice versa, indicating that epitope spreading can occur rapidly in an alloantigen independent manner. Collectively, these data support a model of chronic LTx rejection where the progressive loss of self-tolerance through epitope spreading promotes airway fibrosis. Strategies that target autoreactive Abs may be useful to inhibit chronic rejection of lung grafts.

High definition versus standard definition white light endoscopy for detecting dysplasia in patients with Barrett's esophagus

High-definition endoscopy systems provide superior image resolution. The aim of this study was to assess the utility of high definition compared with standard definition endoscopy system for detecting dysplastic lesions in patients with Barrett's esophagus. A retrospective cohort study of patients with non-dysplastic Barrett's esophagus undergoing routine surveillance was performed. Data were retrieved from the central hospital electronic database. Procedures performed for non-surveillance indications, Barrett's esophagus Prague C0M1 classification with no specialized intestinal metaplasia on histology, patients diagnosed with any dysplasia or cancer on index endoscopy, and procedures using advanced imaging techniques were excluded. Logistic regression models were constructed to estimate adjusted odds ratios and 95% confidence intervals comparing outcomes with standard definition and high-definition systems. The high definition was superior to standard definition system in targeted detection of all dysplastic lesions (odds ratio 3.27, 95% confidence interval 1.27-8.40) as well as overall dysplasia detected on both random and target biopsies (odds ratio 2.36, 95% confidence interval 1.50-3.72). More non-dysplastic lesions were detected with the high-definition system (odds ratio 1.16, 95% confidence interval 1.01-1.33). There was no difference between high definition and standard definition endoscopy in the overall (random and target) high-grade dysplasia or cancers detected (odds ratio 0.93, 95% confidence interval 0.83-1.04). Trainee endoscopists, number of biopsies taken, and male sex were all significantly associated with a higher yield for dysplastic lesions. The use of the high-definition endoscopy system is associated with better targeted detection of any dysplasia during routine Barrett's esophagus surveillance. However, high-definition endoscopy cannot replace random biopsies at present time.

Clindamycin 1% Nano-emulsion Gel Formulation for the Treatment of Acne Vulgaris: Results of a Randomized, Active Controlled, Multicentre, Phase IV Clinical Trial

BACKGROUND

Acne vulgaris of the face is a common dermatological disease with a significant impact on the quality of life, psychosocial development as well as self-esteem of the patients. Nano emulsion gel formulations are said to have various advantages over the conventional formulations.

AIM

The present study was conducted to assess the comparative efficacy and safety of a nano-emulsion gel formulation of clindamycin with its conventional formulation in the treatment of acne vulgaris of the face.

MATERIALS AND METHODS

This prospective, active controlled, multicentric, phase IV clinical trial evaluated the treatment of patients with acne vulgaris of the face by a nano emulsion gel formulation or conventional gel formulation of clindamycin (as phosphate) 1% locally applied twice daily for 12 weeks as per random allocation. Acne lesion counts (inflammatory, non-inflammatory and total) and severity grading were carried out on the monthly scheduled visits along with tolerability assessments.

RESULTS

A total of 200 patients (97 males) were included for Intention to Treat analysis in the trial with 100 patients in each group. Reductions in total (69.3 vs. 51.9%; p<0.001), inflammatory (73.4 vs. 60.6%; p<0.005) and non inflammatory (65.1 vs. 43.7%; p<0.001) acne lesions were reported to be significantly greater with the nano-emulsion gel formulation as compared to the conventional gel formulation. Significantly more reduction in the mean acne severity score was noticeable with the nano-emulsion gel formulation (-1.6 ± 0.9 vs. -1.0 ± 0.8; p<0.001) than the comparator. A trend towards better safety profile of the nano emulsion gel formulation was reported.

CONCLUSION

In the treatment of acne vulgaris of the face, clindamycin nano emulsion gel formulation appears to be more effective than the conventional gel formulation and is also well tolerated.

Discovery of potent inhibitor for matrix metalloproteinase-9 by pharmacophore based modeling and dynamics simulation studies

Matrix metalloproteinase-9 (MMP-9) is an attractive target for anticancer therapy. In the present study ligand based pharmacophore modeling was performed to elucidate the structural elements for a diverse class of MMP-9 inhibitors. The pharmacophore model was validated through Güner-Henry (GH) scoring method. The final pharmacophore model consisted of three hydrogen bond acceptors (HBA), and two ring aromatic regions (RA). This model was utilized to screen the natural compound database to seek novel compounds as MMP-9 inhibitors. The identified hits were validated using molecular docking and molecular dynamics simulation studies. Finally, one compound named Hinokiflavone from Juniperus communis had high binding free energy of -26.54kJ/mol compared with the known inhibitors of MMP-9. Cytotoxicity for hinokiflavone was evaluated by MTT assay. Inhibition of MMP-9 in the presence of hinokiflavone was detected by gelatin zymography and gelatinolytic inhibition assay. Results revealed that the natural compounds derived based on the developed pharmacophore model would be useful for further design and development of MMP-9 inhibitors.

Obstetric outcome of ethnic Turkish women in London: a retrospective case-control study

There is concern that the maternal mortality in ethnic minority women is significantly greater than that of Caucasian British women. The objective of this study was to compare the demographic and obstetric outcomes between these two groups. Data were collected retrospectively over a 2-year period from 148 index and 148 control cases. The study group had statistically similar maternal age, labour duration, blood loss and mode of delivery compared with Caucasian British women (p > 0.05). A total of 68% of Turkish women spoke little or no English; were more likely to be non-smokers and also more likely to be married to unemployed spouses (p = 0.0001). This is the first study comparing obstetric outcomes of immigrant Turkish women with their Caucasian British counterparts. There was no significant difference in maternal or fetal outcomes, which could be attributed to the 'healthy migrant' theory, coupled with increased vigilance in ethnic minority pregnancies.

Regional anthropometric measures associated with the severity of liver injury in patients with non-alcoholic fatty liver disease

BACKGROUND

Not all NAFLD patients are obese and many obese patients do not have NAFLD. Impaired peripheral fat storage may increase the delivery of lipids to the liver and facilitate NAFLD progression.

AIM

To assess the association of anthropometric measures of regional adiposity including arm fat index (AFI) (upper body fat), waist circumference (visceral fat) and body mass index (total body fat) on liver injury and fibrosis in NAFLD.

METHODS

One hundred and forty-one patients with histological evidence of NAFLD were included in this study. Multivariate logistic regression models examined the contribution of age, sex, body mass index, AFI, triceps fold thickness (TST), waist and hip circumference to the odds of liver injury (NAS scores ≥3) and fibrosis (fibrosis scores ≥2) by liver biopsy.

RESULTS

Arm fat index (OR: 0.82, 95% CI: 0.59-0.91) and TST (OR: 0.13, 95% CI: 0.04-0.42) were negatively correlated with NAFLD histological severity. In women, waist circumference was positively correlated with NAFLD severity (OR: 1.21(1.02-1.44). Age (OR: 1.05, 95% CI: 1.01-1.0) and waist circumference (OR: 1.07, 95% CI: 1.00-1.15) were significantly associated with fibrosis risk. In women, AFI (OR: 0.87, 95% CI: 0.76-0.99) and TST (OR: 0.22, 95% CI: 0.05-0.95) were negatively associated with fibrosis risk.

CONCLUSIONS

Regional anthropometric measures are associated with severity of NAFLD in a sex-specific manner. Men and women with lower arm fat depots and women with bigger waist circumference have a greater likelihood of liver injury. Age and waist circumference seem to be associated with liver fibrosis. Simple anthropometric measurements of peripheral fat deposits may help stratify significant liver injury risk.

Molecular dynamics simulations of retinoblastoma protein

Tumor suppressor proteins play a crucial role in cell cycle regulation. Retinoblastoma protein (pRB) is one among them which regulates G1-S transition by binding with transcription factors. The activity of pRB is deregulated by cyclin dependent kinases-mediated hyper-phosphorylation and also due to cancer-derived mutations. In addition, it is also deactivated by binding of viral onco-proteins such as large T antigen, E1A, and E7. These viral proteins initially recognize pRB through their conserved LxCxE motif and facilitate dissociation of preexisting pRB-E2F complex. Based on these features, molecular dynamics (MD) simulation is performed for four different states of pRB for which the crystal structure is available. The unliganded/apo form and complex forms with E2F and E7 peptides reveal the molecular mechanism behind the activation and inactivation of pRB. In addition, the ternary complex of pRB with both E7 and E2F (for which no crystal structure is available) is modeled and simulated to understand the influence of binding of one ligand on the other. The variations in the three major factors such as conformational changes, inter- and intra-molecular interactions, and binding free energies between the apo and complex forms confirm the possibility for designing a small molecule inhibitor to inhibit pRB-E7 interactions without altering the prebound E2F. The present study deals with the molecular modeling and MD simulations of pRB in free and ligand-bound forms and confirms that pRB could be a valid target for the anticancer drug design when the cancer is induced by the viral onco-proteins and forms a clear base for designing E7 antagonists.

T regulatory cells play a significant role in modulating MHC class I antibody-induced obliterative airway disease

The molecular mechanisms leading to the development of chronic lung allograft dysfunction following de novo development of antibodies to mismatched donor MHC remain undefined. We demonstrated that intrabronchial administration of antibodies to MHC class I resulted in induction of both innate and adaptive cellular immune responses characterized by a predominance of Th17 specific to lung associated self-antigens Kα1-tubulin and Collagen-V leading to the development of obliterative airway lesions (OAD), correlate of chronic rejection following human lung transplantation. To determine the role of regulatory T cells (Treg) in the pathogenesis of OAD, we administered anti-MHC class I to mice, in which Treg were depleted by conditional ablation of FoxP3+cells. Under this condition, we observed a threefold increase in pulmonary cellular infiltration, luminal occlusion and fibrous deposition when compared anti-MHC class I Ab administered mice maintaining FoxP3. OAD lesions were accompanied with enhanced accumulation of neutrophils along with self-antigen-specific Th17 and humoral responses. However, IL-17-blockade or adoptive transfer of Treg abrogated OAD. We conclude that Treg exerts a suppressive effect on anti-MHC induced IL-8-mediated neutrophil infiltration and innate immune responses that leads to inhibition of Th17 immune responses to lung associated self-antigens which is critical for development of OAD.

On the perturbation of the H-bonding interaction in ethylene glycol clusters upon hydration

Ab initio and density functional methods have been employed to study the structure, stability, and spectral properties of various ethylene glycol (EG(m)) and ethylene glycol-water (EG(m)W(n)) (m = 1-3, n = 1-4) clusters. The effective fragment potential (EFP) approach was used to explore various possible EG(m)W(n) clusters. Calculated interaction energies of EG(m)W(n) clusters confirm that the hydrogen-bonding interaction between EG molecules is perturbed by the presence of water molecules and vice versa. Further, energy decomposition analysis shows that both electrostatic and polarization interactions predominantly contribute to the stability of these clusters. It was found from the same analysis that ethylene glycol-water interaction is predominant over the ethylene glycol-ethylene glycol and water-water interactions. Overall, the results clearly illustrate that the presence of water disrupts the ethylene glycol-ethylene glycol hydrogen bonds.

Studies on the structure, stability, and spectral signatures of hydride ion-water clusters

The gas-phase structure, stability, spectra, and electron density topography of H(-)W(n) clusters (where n = 1-8) have been calculated using coupled-cluster CCSD(T) and Møller-Plesset second-order perturbation (MP2) theory combined with complete basis set (CBS) approaches. The performance of various density functional theory (DFT) based methods such as B3LYP, M05-2X, M06, M06-L, and M06-2X using 6-311++G(d,p), and aug-cc-pVXZ (aVXZ, where X = D, T, and Q) basis sets has also been assessed by considering values calculated using CCSD(T)/CBS limit as reference. The performance of the functionals has been ranked based on the mean signed/unsigned error. The comparison of geometrical parameters elicits that the geometrical parameters predicted by B3LYP/aVTZ method are in good agreement with those values obtained at MP2/aVTZ level of theory. Results show that M05-2X functional outperform other functionals in predicting the energetics when compared to CCSD(T)/CBS value. On the other hand, values predicted by M06-2X, and M06 methods, are closer to those values obtained from MP2/CBS approach. It is evident from the calculations that H(-)W(n) (where n = 5-8) clusters adopt several interesting structural motifs such as pyramidal, prism, book, Clessidra, cubic, cage, and bag. The important role played by ion-water (O-H···H(-)) and water-water (O-H···O) interactions in determining the stability of the clusters has also been observed. Analysis of the results indicates that the most stable cluster is made up of minimum number of O-H···H(-) interaction in conjugation with the maximum number of O-H···O interactions. The Bader theory of atoms in molecules (AIM) and natural bond orbital (NBO) analyses has also been carried out to characterize the nature of interactions between hydride ion and water molecules. It can be observed from the vibrational spectra of H(-)W(n) clusters, the stretching frequencies involving ion-water interaction always exhibit larger redshift and intensities than that of water-water (inter solvent) interactions.

Endoscopic evaluation of the gastro-duodenal tolerance of short-term analgesic treatment with 25 mg diclofenac-K liquid capsules

BACKGROUND

Diclofenac-potassium (diclofenac--K) 25 mg liquid capsule is absorbed more quickly than the tablet formulation. It offers potential for rapid pain relief, but may alter gastro-duodenal tolerability.

AIM

To evaluate the gastro-duodenal tolerance of diclofenac-K 25 mg liquid capsules vs. diclofenac-K 12.5 mg tablets, acetylsalicylic acid (ASA) 500 mg tablets and ibuprofen 200 mg liquid capsules.

METHODS

In an endoscopist-blinded, randomised, parallel-group study, volunteers received 15 doses of diclofenac-K 25 mg liquid capsules (n = 36), diclofenac-K 2 × 12.5 mg tablets (n = 36), ibuprofen 2 × 200 mg liquid capsules (n = 24) or ASA 2 × 500 mg tablets (n = 36) over 5 days. The primary outcome was the incidence of erosive gastro-duodenal lesions at Day 6. Secondary outcomes included modified Lanza score and change in gastric mucosal prostaglandin synthesis.

RESULTS

The lowest incidence of erosive gastro-duodenal lesions was with diclofenac-K liquid capsules (53%), compared to 61% with diclofenac-K tablets (P = 0.52), 75% with ibuprofen (P = 0.08) and 94% with ASA (P = 0.001). Results were similar for the Lanza scores, although diclofenac-K liquid capsules were significantly superior to ibuprofen liquid capsules (P = 0.04). Diclofenac-K liquid capsules inhibited prostaglandin synthesis by 52% compared to 64% for diclofenac-K tablets (P = 0.10), 50% for ibuprofen (P = 0.85) and 79% for ASA (P = 0.002). With respect to safety, adverse events were most frequent in the ASA group, predominantly gastrointestinal events.

CONCLUSIONS

Mucosal injury with diclofenac-K liquid 25 mg liquid capsules was similar to diclofenac-K 25 mg tablets, significantly lower than ASA 1 g tablets and showed some superiority over ibuprofen 400 mg liquid capsules (EudraCT Number 2009-011278-14).

An obligatory role for lung infiltrating B cells in the immunopathogenesis of obliterative airway disease induced by antibodies to MHC class I molecules

Using a murine model, we demonstrated that endobronchial administration of antibodies (Abs) to major histocompatibility complex (MHC) class I results in cellular infiltration, epithelial metaplasia, fibrosis and obstruction of the small airways (obliterative airway disease [OAD]) mediated predominantly by Th17 responses to self-antigens. This resembles bronchiolitis obliterans syndrome developed following human lung transplantation. Since B cells play a crucial role in induction of autoimmune responses, we defined the role of B cells and its antigen presenting properties in induction of OAD in this study. Anti-MHC class I was administered endobronchially in B(-/-) and wild-type mice. In contrast to wild type, B(-/-) animals did not demonstrate cellular infiltration, epithelial metaplasia and obstruction of airways following anti-MHC. Frequency of K-α1 tubulin and CollagenV-specific IL-17 cells was significantly decreased in B(-/-) mice. As expected, Abs against self-antigens and germinal center formation were not developed in B(-/-) mice. Thus, we conclude that B cells and its antigen presenting capacity play an important role in induction of immune responses to self-antigens and immunopathogenesis of OAD following the administration of anti-MHC. Therefore, strategies to block B-cell and its antigen presenting functions should be considered for preventing the development of chronic rejection.

Meta-analysis: diagnostic medical radiation exposure in inflammatory bowel disease

BACKGROUND

Diagnostic imaging plays a pivotal role in the diagnosis and management of inflammatory bowel disease (IBD); however, increasing use has led to concerns about the malignant potential of ionising radiation. Several studies have demonstrated that diagnostic imaging can result in exposure to potentially harmful levels of ionising radiation in IBD patients.

AIM

To determine the pooled prevalence of increased exposure and pooled odds ratio of risk factors associated with exposure to potentially harmful levels of diagnostic medical radiation.

METHODS

We searched Medline, EMBASE, CINHAL and reference lists of identified articles, without language restrictions in October 2011.

RESULTS

Six studies with 1704 participants provided data on the proportion of patients receiving potentially harmful levels of radiation defined as ≥50 milli-sieverts (mSv)-equivalent to 5 CT abdomen scans. The pooled prevalence was 8.8% (95% CI 4.4-16.8) for IBD patients and 11.1% (95% CI 5.7-20.5%) and 2% (95% CI 0.8-4.9%) for Crohn's disease and ulcerative colitis patients respectively. Five studies involving 2627 participants provided data for risk factors. IBD-related surgery and corticosteroid use were significant with pooled adjusted odds ratio of 5.4 (95% CI 2.6-11.2) and 2.4 (95% CI 1.7-3.4) respectively.

CONCLUSIONS

About 1 in 10 patients may be exposed to potentially harmful levels of diagnostic medical radiation. Corticosteroid use and IBD related surgery increased this risk. Strategies to reduce radiation exposure while assessing disease activity need to be considered.

Orthopaedic surgeons: as strong as an ox and almost twice as clever? Multicentre prospective comparative study

OBJECTIVE

To compare the intelligence and grip strength of orthopaedic surgeons and anaesthetists.

DESIGN

Multicentre prospective comparative study.

SETTING

Three UK district general hospitals in 2011.

PARTICIPANTS

36 male orthopaedic surgeons and 40 male anaesthetists at consultant or specialist registrar grade.

MAIN OUTCOME MEASURES

Intelligence test score and dominant hand grip strength.

RESULTS

Orthopaedic surgeons had a statistically significantly greater mean grip strength (47.25 (SD 6.95) kg) than anaesthetists (43.83 (7.57) kg). The mean intelligence test score of orthopaedic surgeons was also statistically significantly greater at 105.19 (10.85) compared with 98.38 (14.45) for anaesthetists.

CONCLUSIONS

Male orthopaedic surgeons have greater intelligence and grip strength than their male anaesthetic colleagues, who should find new ways to make fun of their orthopaedic friends.

Exposure to hookworms in patients with Crohn's disease: a case-control study

BACKGROUND

Helminths have been used to inhibit intestinal inflammation in patients with Crohn's disease.

AIM

This study was undertaken to determine if there is a protective association of prior hookworm infection with Crohn's disease, in a region where there is epidemiological transition from parasitic and infectious diseases to increased auto-inflammatory diseases.

METHODS

Hookworm exposure was assessed by peripheral blood mononuclear cell (PBMC) activation by hookworm antigens in 78 patients with Crohn's disease and 75 healthy control participants. The change in proportion of T cells exhibiting CD69 after exposure to crude hookworm antigens was measured. Interferon-γ ELISPOT response to a panel of six recombinant hookworm antigens was analysed.

RESULTS

Patients with Crohn's disease were more often from an urban background (P=0.005) compared to controls, while their socioeconomic status was not significantly different. T cell activation (increase in CD3(+) CD69(+) population) by hookworm antigen was significantly higher in controls compared to Crohn's disease patients (P=0.017), while activation by the nonspecific mitogen phytohemagglutinin was similar in both groups. Circulating T memory cells (CD3(+) CD45RO(+)) after exposure to hookworm antigens were not significantly different between the two groups. Mirroring these changes, interferon-γ ELISPOT responses to hookworm antigens were seen in 36 of 75 controls compared to 20 of 78 Crohn's disease patients (Fisher's exact P=0.005). Multivariate analysis indicated that CD3CD69 shifts (P=0.019), ELISPOT reactivity (P=0.039) and place of residence (P=0.024) were all independently associated with Crohn's disease.

CONCLUSION

The inverse association between Crohn's disease and hookworm antigen reactivity is consistent with the hygiene hypothesis, but requires further exploration.

Density functional theory studies on ice nanotubes

The structure and stability of quasi one-dimensional (1D) ice nanotubes (INTs) have been investigated using Density Functional Theory (DFT) based Becke's three parameter Lee-Yang-Parr exchange and correlation functional (B3LYP) method employing various basis sets. Four different INTs, namely, (4,0)-INT, (5,0)-INT, (6,0)-INT, and (8,0)-INT with different lengths have been considered in this study. The calculated stabilization energies (SEs) illustrate that the stability of INT is proportional to its length and diameter. Further, the encapsulation of various gas molecules (CO(2), N(2)O, CO, N(2), and H(2)) inside the INTs has also been investigated. The calculated SEs of different endohedral complexes reveal that all these gas molecules are stable inside the tubes. The Bader's theory of atoms in molecule (AIM) has been used to characterize intra- and inter-ring H-bonding interactions. The electron density topological parameters derived from AIM theory brings out the difference between the intra- and inter-ring H-bonds of INTs.

C60-fullerene binds with the ATP binding domain of human DNA topoiosmerase II alpha

C60-fullerene has promising biological applications, such as drug delivery, biosensors, diagnosis and theraupetics. Despite of these applications, several in vitro studies have also reported the DNA damaging potential of this nanomaterial. Though, very little is known about the mechanism involved behind the fullerene mediated DNA damage. Our study was aimed at identifying the binding site of fullerene in the ATP binding domain of human topoisomerase II alpha, a major enzyme involved in maintaining DNA topology. In silico studies of fullerene with the enzyme demonstrated that it can interact with the active site residues of this enzyme through hydrophobic, pi-stacking and van der Waals interactions and could inhibit the activity of this enzyme.

High definition colonoscopy vs. standard video endoscopy for the detection of colonic polyps: a meta-analysis

BACKGROUND AND STUDY AIMS

High definition colonoscopy may improve adenoma detection rates but studies report conflicting results. The aim of this meta-analysis was to compare the diagnostic yield of colonic polyps between high definition colonoscopy and standard video endoscopy (SVE).

METHODS

Various electronic databases were searched for articles reporting on high definition colonoscopy. The pooled incremental yield and pooled weighted mean difference of high definition colonoscopy over SVE for polyp detection was determined.

RESULTS

Five studies involving 4422 patients provided data on the total number of polyps detected. The incremental yield of high definition colonoscopy for the detection of any polyp was 3.8 % (95 % confidence interval [CI] 1 % - 6.7 %) with a number needed to treat (NNT) of 26. For the detection of adenomatous polyps the incremental yield was 3.5 % (95 %CI 0.9 % - 6.1 %) with an NNT of 28. There were no differences between high definition and SVE in the detection of high risk adenomas, with an incremental yield of -0.1 % (95 %CI -1.7 % to 1.6 %). When grouped according to the overall adenoma detection rate of the studies (> 50 % or < 50 %) the pooled weighted mean difference in small adenoma detection was better with high definition colonoscopy ( P = 0.035).

CONCLUSIONS

There were marginal differences between high definition colonoscopy and SVE for the detection of colonic polyps/adenomas. High definition colonoscopy did not improve the detection of high risk adenomas. Due to differences in the adenoma detection rate between the studies and the nonrandomized study design of three of the five studies, these results need to be interpreted with caution. Prospective randomized trials looking at long term outcomes such as rates of interval or missed cancers are needed to clarify the clinical implications.

Interaction of polyalanine alpha-helix with carbon nanotube

The application of carbon nanotubes (CNT) in the area of biology such as Drug delivery vehicle and Biosensors calls for the basic understanding of the CNT's with biological macromolecules like proteins, DNA, Carbohydrates and lipids. CNT is known to be highly hydrophobic in nature. Our study reveals that the inherent hydrophobic nature of CNT is capable of disturbing the alpha-helical protein secondary structure. Thus our study provides mechanistic understanding of the loss in the alpha-helicity of the proteins in the presence of CNT. Our study reveals that the nanomaterials should be suitably modified for biological applications.

Quantum mechanical studies on interaction of carbohydrate with nanomaterials

The interactions between the fragment of various nanotubes (NTs) and carbohydrate (beta-D-glucose) has been investigated using quantum mechanical methods using different basis sets in gas phase. The most stable isomer of each complex favors multiple CH...pi contacts which arise due to the orientation of the hydrophobic surface of the carbohydrate with reference to the curved or planar aromatic systems. The carbohydrate recognition surface of the aromatic system referred as "three point landing surface" are important in the stabilization of carbohydrate-pi complexes.

Source transformation device formed by one-dimensional photonic crystal

Photonic bandgap structures can also be utilized for the realization of transformational optical devices like metamaterials. In this Letter, the possibility of cylindrical to plane wave source transformation in an open cavity formed by one dimensional photonic crystal is demonstrated. It is observed that the gap solitary wave behavior at the near-bandgap regime is fair enough to produce highly directional plane waves out of the point source placed inside the open cavity. The limitations of such a source transformation device are governed by the strength of the bandgap that decides the amplitude of the emitted plane waves.

Esophageal stents for benign refractory strictures: a meta-analysis

BACKGROUND AND AIMS

Fully covered self-expanding removable stents (SERS) have been considered a viable alternative to serial bougienage. The primary aim of this meta-analysis was to determine the efficacy of SERS for refractory esophageal strictures.

METHODS

Medline, Embase, and PubMed databases were searched using the keywords "esophageal stricture," "esophageal stents," "benign stricture," "dysphagia," "caustic," "peptic stricture," "anastomotic," "radiation," and "dysphagia" for the period from January 1965 to June 2010. Articles were selected for review independently by two authors (T. T. and J. M.) on the basis of predefined inclusion criteria, and the data collected. A meta-analysis using a random effects model was done.

RESULTS

Eight studies with a total of 199 patients were included in the final analysis (104-males, average age 56 years, range: 49 - 68 years). Overall, 46.2 % of patients (95 %CI: 38.3 % - 54.1 %) had dysphagia improvement at an average follow up of 74 weeks. There was a significant difference ( P = 0.019) in dysphagia improvement for patients with Polyflex stents (55.3 %; 95 %CI: 44.4 % - 65.9 %) versus nitinol stents (21.8 %; 95 %CI: 13.7 % - 33.7 %). On meta-regression, patient sex ( P = 0.80), patient age ( P = 0.725), corrosive etiology ( P = 0.30), stricture location ( P = 0.273), stricture length ( P = 0.32), time of removal ( P = 0.056), and duration of follow-up (0.35) had no significance influence on the outcome. The migration rate was 26.4 % (95 %CI: 25.3 % - 39.3 %).

CONCLUSIONS

Although the efficacy of SERS placement in benign refractory strictures is 46.2 %, it is associated with migration rate of 26.4 %. Nevertheless, the use of these temporary stents, which can be successfully removed in 87 % of patients, is an alluring prospect for treating patients with this difficult condition.