Azathioprine for prevention of clinical recurrence in Crohn's disease patients with severe endoscopic recurrence: an IG-IBD randomized double-blind trial

OBJECTIVE

The recurrence of Crohn's Disease after ileo-colonic resection is a crucial issue. Severe endoscopic lesions increase the risk of developing early symptoms. Prevention and treatment of post-operative Endoscopic Recurrence (ER) have been studied with conflicting results. We compare effi cacy of azathioprine (AZA) vs. high-dose 5-aminosalicylic acid (5-ASA) in preventing clinical recurrence and treating severe post-operative ER.

PATIENTS AND METHODS

We performed a 1-year multicenter randomized double-blind double-dummy trial. Primary end-points were endoscopic improvement and therapeutic failure (clinical recurrence or drug discontinuation due to lack of efficacy or adverse events) 12 months after randomization. We also performed a post-trial analysis on symptomatic and endoscopic outcomes 10 years after the beginning of the trial, with a median follow-up of 60 months.

RESULTS

Therapeutic failure occurred in 8 patients (17.4%) within 12 months from randomization, with no significant difference between patients treated with 5-ASA (20.8%, 5 patients) and those with AZA (13.6%, 3 patients). Therapeutic failure was due to clinical recurrence in the 5-ASA group and to adverse events in the AZA group. Endoscopic improvement at 12 months was observed in 8 patients, 2 (11.8%) in the 5-ASA group and 6 (30%) in the AZA group. No serious adverse event was recorded. At the post-trial analysis (median follow-up 60 months), 47.8% (22/46) of patients experienced clinical recurrence: 54.2% (13/24) in the 5-ASA group and 40.9% (9/22) in the AZA group, p=0.546. Patients treated with AZA had lower risk of drug escalation. Clinical recurrence was associated with smoking (p=0.031) and previous surgery (p=0.003).

CONCLUSIONS

Our trial indicates that there was no difference in terms of treatment failure between 5-ASA and AZA in patients with severe ER. The main limit of AZA is its less favorable safety profile.

Determination of Total Dietary Fiber (CODEX Definition) by Enzymatic-Gravimetric Method and Liquid Chromatography: Collaborative Study

A method for the determination of total dietary fiber (TDF), as defined by the CODEX Alimentarius, was validated in foods. Based upon the principles of AOAC Official MethodsSM 985.29, 991.43, 2001.03, and 2002.02, the method quantitates high- and low-molecular-weight dietary fiber (HMWDF and LMWDF, respectively). In 2007, McCleary described a method of extended enzymatic digestion at 37C to simulate human intestinal digestion followed by gravimetric isolation and quantitation of HMWDF and the use of LC to quantitate low-molecular-weight soluble dietary fiber (LMWSDF). The method thus quantitates the complete range of dietary fiber components from resistant starch (by utilizing the digestion conditions of AOAC Method 2002.02) to digestion resistant oligosaccharides (by incorporating the deionization and LC procedures of AOAC Method 2001.03). The method was evaluated through an AOAC collaborative study. Eighteen laboratories participated with 16 laboratories returning valid assay data for 16 test portions (eight blind duplicates) consisting of samples with a range of traditional dietary fiber, resistant starch, and nondigestible oligosaccharides. The dietary fiber content of the eight test pairs ranged from 11.57 to 47.83. Digestion of samples under the conditions of AOAC Method 2002.02 followed by the isolation and gravimetric procedures of AOAC Methods 985.29 and 991.43 results in quantitation of HMWDF. The filtrate from the quantitation of HMWDF is concentrated, deionized, concentrated again, and analyzed by LC to determine the LMWSDF, i.e., all nondigestible oligosaccharides of degree of polymerization 3. TDF is calculated as the sum of HMWDF and LMWSDF. Repeatability standard deviations (sr) ranged from 0.41 to 1.43, and reproducibility standard deviations (sR) ranged from 1.18 to 5.44. These results are comparable to other official dietary fiber methods, and the method is recommended for adoption as Official First Action.

Determination of Campesterol, Stigmasterol, and Beta-Sitosterol in Saw Palmetto Raw Materials and Dietary Supplements by Gas Chromatography: Collaborative Study

An interlaboratory study was conducted to evaluate a method for the determination of campesterol, stigmasterol, and beta-sitosterol in saw palmetto raw materials and dietary supplements at levels >1.00 mg/100 g based on a 23 g sample. Test samples were saponified at high temperature with ethanolic KOH solution. The unsaponifiable fraction containing phytosterols (campesterol, stigmasterol, and beta-sitosterol) was extracted with toluene. Phytosterols were derivatized to trimethylsilyl ethers and then quantified by gas chromatography with hydrogen flame ionization detection. Twelve blind duplicates, one of which was fortified, were successfully analyzed by 10 collaborators. Recoveries were obtained for the sample that was fortified. The results were 99.8, 111, and 111% for campesterol, stigmasterol, and beta-sitosterol, respectively. For repeatability, the relative standard deviation (RSDr) ranged from 3.93 to 17.3% for campesterol, 3.56 to 22.7% for stigmasterol, and 3.70 to 43.9% for beta-sitosterol. For reproducibility, the RSDR ranged from 7.97 to 22.6%, 0 to 26.7%, and 5.27 to 43.9% for campesterol, stigmasterol, and beta-sitosterol, respectively. Overall, the Study Director approved 5 materials with acceptable HorRat values for campesterol, stigmasterol, and beta-sitosterol ranging from 1.02 to 2.16.

Action of Newcastle Disease Virus on Human Blood Platelets

Newcastle Disease Virus induces a viscous metamorphosis like process in washed platelets.

This virus liberates from platelets lactic dehydrogenase and pyruvate kinase, depletes their ATP content and impairs their ability to concentrate 5-hydroxy-tryptamine.

Since Newcastle Disease Virus has adenosine triphosphatase activity, a possible role of this viral enzyme in the production of viscous metamorphosis and in inhibition of clot retraction is discussed.

Treatment of platelets by Newcastle Disease Virus or by particulate fraction from normal allantoic fluid causes liberation of a platelet factor 3-like substance.

Interface characterization of epitaxial Fe/MgO/Fe magnetic tunnel junctions

Following predictions by first-principles theory of a huge tunnel magnetoresistance (TMR) effect in epitaxial Fe/MgO/Fe magnetic tunnel junctions (MTJs), measured magnetoresistance (MR) ratios of about 200% at room temperature (RT) have been reported in MgO-based epitaxial MTJs. Recently, a MR ratio of about 600% has been reported at RT in MgO-based MTJs prepared by magnetron sputtering, using amorphous CoFeB as the ferromagnetic electrode. These MTJs show great potential for application in spintronic devices. Fully epitaxial MTJs are excellent model systems that enhance our understanding of the spin-dependent tunneling process as the interface is well defined and can be fully characterized. Both theoretical calculations and experimental results clearly indicate that the interfacial structure plays a crucial role in the coherent tunneling across a single crystal MgO barrier, especially in epitaxial MgO-based MTJs grown by molecular beam epitaxy (MBE). Surface X-ray diffraction, Auger electron spectroscopy, X-ray absorption spectra, and X-ray magnetic circular dichroism techniques have been reported previously for interface characterization. However, no consistent viewpoint has been reached on the interfacial structures (such as FeO layer formation at the bottom Fe/MgO interface), and it is still an open issue. In this article, our recent studies on the interface characterization of MgO-based epitaxial MTJs by X-ray photoelectron spectroscopy, high resolution transmission electron microscopy, and spin-dependent tunneling spectroscopy, will be presented.

Local injection of infliximab in severe fistulating perianal Crohn's disease: an open uncontrolled study

BACKGROUND

Perianal fistulas are frequent complications of Crohn's disease. Intravenous infliximab can control perianal disease and promote perianal fistula closure. Perifistular infliximab injections have been proposed for patients who are intolerant or unresponsive to intravenous therapy. The aim of this study was to assess the long-term efficacy of surgical treatment combined with local infliximab therapy.

METHODS

A prospective cohort study was designed. Twelve patients with Crohn's disease and high/complex transphincteric and intrasphincteric perianal fistulas refractory to other treatment were submitted to core-out fistulectomies, plus perifistular injections of infliximab (20-25 mg in 15-20 ml of 5% glucose) every 4-6 weeks. The main outcome measure was the clinical closure of all perianal fistulas. A 95% confidence interval was calculated for short- and long-term fistula closure rates.

RESULTS

None of the procedures were associated with local or systemic adverse effects. Four patients did not complete treatment, two because of relapse of intestinal symptoms, which required intravenous infliximab. In one case, treatment with intravenous infliximab was complicated by a hypersensitivity reaction. Eight patients continued treatment until all perianal fistulas were closed and setons were removed (median: 5 sessions). Persistent closure was observed in seven (87.5%, 95% CI: 47.4-99.6) of the eight patients 12 months after completion of treatment and in five (62.5%; 95% CI: 24.5-91.5) of eight at the end of follow-up (range: 19-43 months, median: 35 months).

CONCLUSIONS

The cohort we examined is small, but fistulectomy combined with repeated perifistular injections of infliximab appears to be safe and may help in fistula healing. However, in most patients, permanent closure of all fistulas is not achieved.

Interlayer diffusion studies of a Laves phase exchange spring superlattice

Rare earth Laves phase (RFe(2)) superlattice structures grown at different temperatures are studied using x-ray reflectivity (XRR), x-ray diffraction, and transmission electron microscopy. The optimized molecular beam epitaxy growth condition is matched with the XRR simulation, showing minimum diffusion/roughness at the interfaces. Electron microscopy characterization reveals that the epitaxial growth develops from initial 3D islands to a high quality superlattice structure. Under this optimum growth condition, chemical analysis by electron energy loss spectroscopy with high spatial resolution is used to study the interface. The analysis shows that the interface roughness is between 0.6 and 0.8 nm and there is no significant interlayer diffusion. The locally sharp interface found in this work explains the success of simple structural models in predicting the magnetic reversal behavior of Laves exchange spring superlattices.

The influence of interfacial roughness on the coherence of structure and magnetic coupling across barriers in Fe/MgO multilayers

Single-crystal Fe/MgO multilayers are model systems in which to study magnetic tunnel junctions. We find that the interfacial roughness leads to the loss of coherence of the crystal structure. For thick MgO layers ferromagnetic (FM) ordering is found using polarized neutron reflectivity (PNR). For thin MgO layers magnetization measurements reveal the presence of antiferromagnetic (AF) interactions, but no long-range AF order is found using PNR. After cycling in a hysteresis loop, FM correlations are found at the coercive point, and this will limit the maximum tunnelling magnetoresistance.