Functional and structural asymmetry suggest a unifying principle for catalysis in membrane-bound pyrophosphatases.

Membrane-bound pyrophosphatases (M-PPases) are homodimeric primary ion pumps that couple the transport of Na+- and/or H+ across membranes to the hydrolysis of pyrophosphate. Their role in the virulence of protist pathogens like Plasmodium falciparum makes them an intriguing target for structural and functional studies. Here, we show the first structure of a K+-independent M-PPase, asymmetric and time-dependent substrate binding in time-resolved structures of a K+-dependent M-PPase and demonstrate pumping-before-hydrolysis by electrometric studies. We suggest how key residues in helix 12, 13, and the exit channel loops affect ion selectivity and K+-activation due to a complex interplay of residues that are involved in subunit-subunit communication. Our findings not only explain ion selectivity in M-PPases but also why they display half-of-the-sites reactivity. Based on this, we propose, for the first time, a unified model for ion-pumping, hydrolysis, and energy coupling in all M-PPases, including those that pump both Na+ and H+.

PTCHD1 Binds Cholesterol but Not Sonic Hedgehog, Suggesting a Distinct Cellular Function.

Deleterious mutations in the X-linked Patched domain-containing 1 (PTCHD1) gene may account for up to 1% of autism cases. Despite this, the PTCHD1 protein remains poorly understood. Structural similarities to Patched family proteins point to a role in sterol transport, but this hypothesis has not been verified experimentally. Additionally, PTCHD1 has been suggested to be involved in Hedgehog signalling, but thus far, the experimental results have been conflicting. To enable a variety of biochemical and structural experiments, we developed a method for expressing PTCHD1 in Spodoptera frugiperda cells, solubilising it in glycol-diosgenin, and purifying it to homogeneity. In vitro and in silico experiments show that PTCHD1 function is not interchangeable with Patched 1 (PTCH1) in canonical Hedgehog signalling, since it does not repress Smoothened in Ptch1-/- mouse embryonic fibroblasts and does not bind Sonic Hedgehog. However, we found that PTCHD1 binds cholesterol similarly to PTCH1. Furthermore, we identified 13 PTCHD1-specific protein interactors through co-immunoprecipitation and demonstrated a link to cell stress responses and RNA stress granule formation. Thus, our results support the notion that despite structural similarities to other Patched family proteins, PTCHD1 may have a distinct cellular function.

Unexpected structures formed by the kinase RET C634R mutant extracellular domain suggest potential oncogenic mechanisms in MEN2A.

The RET receptor tyrosine kinase plays a pivotal role in cell survival, proliferation, and differentiation, and its abnormal activation leads to cancers through receptor fusions or point mutations. Mutations that disrupt the disulfide network in the extracellular domain (ECD) of RET drive multiple endocrine neoplasia type 2A (MEN2A), a hereditary syndrome associated with the development of thyroid cancers. However, structural details of how specific mutations affect RET are unclear. Here, we present the first structural insights into the ECD of the RET(C634R) mutant, the most common mutation in MEN2A. Using electron microscopy, we demonstrate that the C634R mutation causes ligand-independent dimerization of the RET ECD, revealing an unusual tail-to-tail conformation that is distinct from the ligand-induced signaling dimer of WT RET. Additionally, we show that the RETC634R ECD dimer can form complexes with at least two of the canonical RET ligands and that these complexes form very different structures than WT RET ECD upon ligand binding. In conclusion, this structural analysis of cysteine-mutant RET ECD suggests a potential key mechanism of cancer induction in MEN2A, both in the absence and presence of its native ligands, and may offer new targets for therapeutic intervention.

Exploration of Pyrazolo[1,5-a]pyrimidines as Membrane-Bound Pyrophosphatase Inhibitors.

Inhibition of membrane-bound pyrophosphatase (mPPase) with small molecules offer a new approach in the fight against pathogenic protozoan parasites. mPPases are absent in humans, but essential for many protists as they couple pyrophosphate hydrolysis to the active transport of protons or sodium ions across acidocalcisomal membranes. So far, only few nonphosphorus inhibitors have been reported. Here, we explore the chemical space around previous hits using a combination of screening and synthetic medicinal chemistry, identifying compounds with low micromolar inhibitory activities in the Thermotoga maritima mPPase test system. We furthermore provide early structure-activity relationships around a new scaffold having a pyrazolo[1,5-a]pyrimidine core. The most promising pyrazolo[1,5-a]pyrimidine congener was further investigated and found to inhibit Plasmodium falciparum mPPase in membranes as well as the growth of P. falciparum in an ex vivo survival assay.

Impact of age in critically Ill infected patients: a post-hoc analysis of the INFAUCI study.

PURPOSE: Older patients are the fastest expanding subgroup of intensive care units (ICU) and are particularly susceptible to bacterial infections and sepsis. The aim of this study was to address the epidemiology and the main determinants of outcome of infection in old and very old patients admitted to ICU. METHODS: We performed a post hoc analysis of all infected patients admitted to ICU enrolled in a 1-year prospective, observational, multipurpose study. Patients aged < 65, 65-74 and ≥ 75 years were compared. RESULTS: Of the 1652 patients included, 50% were older than 65 years. There were no significant differences between young, old and very old patients in either ICU, hospital length of stay, or nosocomial infection. All-cause mortality was significantly higher in participants aged ≥ 75. Increased Gram-negative microorganisms' isolates occurred in > 65 years (25% versus 31%; p = 0.034). Multidrug-resistant (MDR) microorganisms were directly associated to inappropriate empiric antibiotic therapy (OR 4.73; 95% CI 2.99-7.47) and inversely associated with community-acquired infection (OR 0.39; 95% CI 0.19-0.83). Age (65-74 years: OR 1.10; 95% CI 0.64-1.90 and ≥ 75 years: OR 1.52; 95% CI 0.89-2.59) and sepsis severity (sepsis: OR 0.67; 95% CI 0.18-2.46; severe sepsis: OR 1.17; 95% CI 0.40-3.44; septic shock: OR 0.77; 95% CI 0.27-2.24) were not associated to MDR bacteria. CONCLUSION: Patients > 65 years accounted for 50% of infected patients admitted to an ICU. ICU and hospital length of stay, and nosocomial infection did not increase with age. Age did predispose to increased risk for infection by Gram-negatives. These findings may optimize strategies for infection management in older patients.

Expression and purification of the extracellular domain of wild-type humanRET and the dimeric oncogenic mutant C634R.

The receptor tyrosine kinase RET is essential in a variety of cellular processes. RET gain-of-function is strongly associated with several cancers, notably multiple endocrine neoplasia type 2A (MEN 2A), while RET loss-of-function causes Hirschsprung's disease and Parkinson's disease. To investigate the activation mechanism of RET as well as to enable drug development, over-expressed recombinant protein is needed for in vitro functional and structural studies. By comparing insect and mammalian cells expression of the RET extracellular domain (RETECD), we showed that the expression yields of RETECD using both systems were comparable, but mammalian cells produced monomeric functional RETECD, whereas RETECD expressed in insect cells was non-functional and multimeric. This was most likely due to incorrect disulfide formation. By fusing an Fc tag to the C-terminus of RETECD, we were able to produce, in HEK293T cells, dimeric oncogenic RETECD (C634R) for the first time. The protein remained dimeric even after cleavage of the tag via the cysteine disulfide, as in full-length RET in the context of MEN 2A and related pathologies. Our work thus provides valuable tools for functional and structural studies of the RET signaling system and its oncogenic activation mechanisms.

Evolutionary journey and characterisation of a novel pan-gene associated with beer strains of Saccharomyces cerevisiae.

The sequencing of over a thousand Saccharomyces cerevisiae genomes revealed a complex pangenome. Over one third of the discovered genes are not present in the S. cerevisiae core genome but instead are often restricted to a subset of yeast isolates and thus may be important for adaptation to specific environmental niches. We refer to these genes as "pan-genes," being part of the pangenome but not the core genome. Here, we describe the evolutionary journey and characterisation of a novel pan-gene, originally named hypothetical (HYPO) open-reading frame. Phylogenetic analysis reveals that HYPO has been predominantly retained in S. cerevisiae strains associated with brewing but has been repeatedly lost in most other fungal species during evolution. There is also evidence that HYPO was horizontally transferred at least once, from S. cerevisiae to Saccharomyces paradoxus. The phylogenetic analysis of HYPO exemplifies the complexity and intricacy of evolutionary trajectories of genes within the S. cerevisiae pangenome. To examine possible functions for Hypo, we overexpressed a HYPO-GFP fusion protein in both S. cerevisiae and Saccharomyces pastorianus. The protein localised to the plasma membrane where it accumulated initially in distinct foci. Time-lapse fluorescent imaging revealed that when cells are grown in wort, Hypo-gfp fluorescence spreads throughout the membrane during cell growth. The overexpression of Hypo-gfp in S. cerevisiae or S. pastorianus strains did not significantly alter cell growth in medium-containing glucose, maltose, maltotriose, or wort at different concentrations.

New penta-saccharide-bearing tripod amphiphiles for membrane protein structure studies.

Integral membrane proteins either alone or as complexes carry out a range of key cellular functions. Detergents are indispensable tools in the isolation of membrane proteins from biological membranes for downstream studies. Although a large number of techniques and tools, including a wide variety of detergents, are available, purification and structural characterization of many membrane proteins remain challenging. In the current study, a new class of tripod amphiphiles bearing two different penta-saccharide head groups, designated TPSs, were developed and evaluated for their ability to extract and stabilize a range of diverse membrane proteins. Variations in the structures of the detergent head and tail groups allowed us to prepare three sets of the novel agents with distinctive structures. Some TPSs (TPS-A8 and TPS-E7) were efficient at extracting two proteins in a functional state while others (TPS-E8 and TPS-E10L) conferred marked stability to all membrane proteins (and membrane protein complexes) tested here compared to a conventional detergent. Use of TPS-E10L led to clear visualization of a receptor-Gs complex using electron microscopy, indicating profound potential in membrane protein research.

Tandem malonate-based glucosides (TMGs) for membrane protein structural studies.

High-resolution membrane protein structures are essential for understanding the molecular basis of diverse biological events and important in drug development. Detergents are usually used to extract these bio-macromolecules from the membranes and maintain them in a soluble and stable state in aqueous solutions for downstream characterization. However, many eukaryotic membrane proteins solubilized in conventional detergents tend to undergo structural degradation, necessitating the development of new amphiphilic agents with enhanced properties. In this study, we designed and synthesized a novel class of glucoside amphiphiles, designated tandem malonate-based glucosides (TMGs). A few TMG agents proved effective at both stabilizing a range of membrane proteins and extracting proteins from the membrane environment. These favourable characteristics, along with synthetic convenience, indicate that these agents have potential in membrane protein research.

Butane-1,2,3,4-tetraol-based amphiphilic stereoisomers for membrane protein study: importance of chirality in the linker region.

Amphiphile selection is a crucial step in membrane protein structural and functional study. As conventional detergents have limited scope and utility, novel agents with enhanced efficacy need to be developed. Although a large number of novel agents have been reported, so far there has been no systematically designed comparative study of the protein stabilization efficacy of stereo-isomeric amphiphiles. Here we designed and prepared a novel class of stereo-isomeric amphiphiles, designated butane-1,2,3,4-tetraol-based maltosides (BTMs). These stereoisomers showed markedly different behaviour for most of the targeted membrane proteins depending on the chirality of the linker region. These findings indicate an important role for detergent stereochemistry in membrane protein stabilization. In addition, we generally observed enhanced detergent efficacy with increasing alkyl chain length, reinforcing the importance of the balance between hydrophobicity and hydrophilicity in detergent design. The stereo-isomeric difference in detergent efficacy observed provides an important design principle for the development of novel amphiphiles for membrane protein manipulation.

Resorcinarene-Based Facial Glycosides: Implication of Detergent Flexibility on Membrane-Protein Stability.

As a membrane-mimetic system, detergent micelles are popularly used to extract membrane proteins from lipid environments and to maintain their solubility and stability in an aqueous medium. However, many membrane proteins encapsulated in conventional detergents tend to undergo structural degradation during extraction and purification, thus necessitating the development of new agents with enhanced properties. In the current study, two classes of new amphiphiles are introduced, resorcinarene-based glucoside and maltoside amphiphiles (designated RGAs and RMAs, respectively), for which the alkyl chains are facially segregated from the carbohydrate head groups. Of these facial amphiphiles, two RGAs (RGA-C11 and RGA-C13) conferred markedly enhanced stability to four tested membrane proteins compared to a gold-standard conventional detergent. The relatively high water solubility and micellar stability of the RGAs compared to the RMAs, along with their generally favourable behaviours for membrane protein stabilisation described here, are likely to be, at least in part, a result of the high conformational flexibility of these glucosides. This study suggests that flexibility could be an important factor in determining the suitability of new detergents for membrane protein studies.

Conformationally Preorganized Diastereomeric Norbornane-Based Maltosides for Membrane Protein Study: Implications of Detergent Kink for Micellar Properties.

Detergents are essential tools for functional and structural studies of membrane proteins. However, conventional detergents are limited in their scope and utility, particularly for eukaryotic membrane proteins. Thus, there are major efforts to develop new amphipathic agents with enhanced properties. Here, a novel class of diastereomeric agents with a preorganized conformation, designated norbornane-based maltosides (NBMs), were prepared and evaluated for their ability to solubilize and stabilize membrane proteins. Representative NBMs displayed enhanced behaviors compared to n-dodecyl-ß-d-maltoside (DDM) for all membrane proteins tested. Efficacy of the individual NBMs varied depending on the overall detergent shape and alkyl chain length. Specifically, NBMs with no kink in the lipophilic region conferred greater stability to the proteins than NBMs with a kink. In addition, long alkyl chain NBMs were generally better at stabilizing membrane proteins than short alkyl chain agents. Furthermore, use of one well-behaving NBM enabled us to attain a marked stabilization and clear visualization of a challenging membrane protein complex using electron microscopy. Thus, this study not only describes novel maltoside detergents with enhanced protein-stabilizing properties but also suggests that overall detergent geometry has an important role in determining membrane protein stability. Notably, this is the first systematic study on the effect of detergent kinking on micellar properties and associated membrane protein stability.

Patients' estimations of the importance of preventive health services: a nationwide, population-based cross-sectional study in Portugal.

OBJECTIVES: To determine, in the context of primary care preventive health services, the level of importance that Portuguese patients attribute to different preventive activities. DESIGN: Cross-sectional study. SETTING: Primary Healthcare, Portugal. PARTICIPANTS: 1000 Portuguese adults selected by a stratified cluster sampling design were invited to participate in a computer-assisted telephone survey. Persons with a cognitive or physical disability that hampered the ability to complete a telephone interview and being a nursing home resident or resident in any other type of collective dwelling were excluded. OUTCOMES: Mean level of importance assigned to 20 different medical preventive activities, using a scale of 1-10, with 1 corresponding to 'no importance for you and your health' and 10 indicating 'very important'. RESULTS: The mean level of importance assigned to medical preventive activity was 7.70 (95% CI 7.60 to 7.80). Routine blood and urine tests were considered the most important, with an estimated mean of 9.15 (95% CI 9.07 to 9.24), followed by female-specific interventions (Pap smear, mammography and gynaecological and breast ultrasounds), with mean importance ranging from 8.45 (95% CI 8.23 to 8.63) for mammography to 8.56 (95% CI 8.36 to 8.76) for Pap smear. Advice regarding alcohol consumption (6.18; 95% CI 5.96 to 6.39) and tobacco consumption (5.99; 95% CI 5.75 to 6.23) were considered much less important. CONCLUSIONS: Our results reveal that Portuguese patients overestimate the importance of preventive medical activities, tend to give more importance to diagnostic and laboratory tests than to lifestyle measures, do not discriminate tests that are important and evidence-based, and seem not be aware of the individualisation of risk. Family physicians should be aware of these optimistic expectations, because these can influence the doctor-patient relationship when discussing these interventions and incorporating personalised risk.

Tandem neopentyl glycol maltosides (TNMs) for membrane protein stabilisation.

A novel class of detergents, designated tandem neopentyl glycol maltosides (TNMs), were evaluated with four target membrane proteins. The best detergent varied depending on the target, but TNM-C12L and TNM-C11S were notable for their ability to confer increased membrane protein stability compared to DDM. These agents have potential for use in membrane protein research.

Mesitylene-Cored Glucoside Amphiphiles (MGAs) for Membrane Protein Studies: Importance of Alkyl Chain Density in Detergent Efficacy.

Detergents serve as useful tools for membrane protein structural and functional studies. Their amphipathic nature allows detergents to associate with the hydrophobic regions of membrane proteins whilst maintaining the proteins in aqueous solution. However, widely used conventional detergents are limited in their ability to maintain the structural integrity of membrane proteins and thus there are major efforts underway to develop novel agents with improved properties. We prepared mesitylene-cored glucoside amphiphiles (MGAs) with three alkyl chains and compared these agents with previously developed xylene-linked maltoside agents (XMAs) with two alkyl chains and a conventional detergent (DDM). When these agents were evaluated for four membrane proteins including a G protein-coupled receptor (GPCR), some agents such as MGA-C13 and MGA-C14 resulted in markedly enhanced stability of membrane proteins compared to both DDM and the XMAs. This favourable behaviour is due likely to the increased hydrophobic density provided by the extra alkyl chain. Thus, this study not only describes new glucoside agents with potential for membrane protein research, but also introduces a new detergent design principle for future development.

A Class of Rigid Linker-bearing Glucosides for Membrane Protein Structural Study.

Membrane proteins are amphipathic bio-macromolecules incompatible with the polar environments of aqueous media. Conventional detergents encapsulate the hydrophobic surfaces of membrane proteins allowing them to exist in aqueous solution. Membrane proteins stabilized by detergent micelles are used for structural and functional analysis. Despite the availability of a large number of detergents, only a few agents are sufficiently effective at maintaining the integrity of membrane proteins to allow successful crystallization. In the present study, we describe a novel class of synthetic amphiphiles with a branched tail group and a triglucoside head group. These head and tail groups were connected via an amide or ether linkage by using a tris(hydroxylmethyl)aminomethane (TRIS) or neopentyl glycol (NPG) linker to produce TRIS-derived triglucosides (TDTs) and NPG-derived triglucosides (NDTs), respectively. Members of this class conferred enhanced stability on target membrane proteins compared to conventional detergents. Because of straightforward synthesis of the novel agents and their favourable effects on a range of membrane proteins, these agents should be of wide applicability to membrane protein science.

Validity and reliability of the European portuguese version of neuropsychiatric inventory in an institutionalized sample.

BACKGROUND: Neuropsychiatric symptoms are very common in dementia and have been associated with patient and caregiver distress, increased risk of institutionalization and higher costs of care. In this context, the neuropsychiatric inventory (NPI) is the most widely used comprehensive tool designed to measure neuropsychiatric Symptoms in geriatric patients with dementia. The aim of this study was to present the validity and reliability of the European Portuguese version of NPI. METHODS: A cross-sectional study was carried out with a convenience sample of institutionalized patients (≥ 50 years old) in three nursing homes in Portugal. All patients were also assessed with mini-mental state examination (MMSE) (cognition), geriatric depression scale (GDS) (depression) and adults and older adults functional assessment inventory (IAFAI) (functionality). NPI was administered to a formal caregiver, usually from the clinical staff. Inter-rater and test-retest reliability were assessed in a subsample of 25 randomly selected subjects. RESULTS: The sample included 166 elderly, with a mean age of 80.9 (standard deviation: 10.2) years. Three out of the NPI behavioral items had negative correlations with MMSE: delusions (rs = -0.177, P = 0.024), disinhibition (rs = -0.174, P = 0.026) and aberrant motor activity (rs = -0.182, P = 0.020). The NPI subsection of depression/dysphoria correlated positively with GDS total score (rs = 0.166, P = 0.038). NPI showed good internal consistency (overall α = 0.766; frequency α = 0.737; severity α = 0.734). The inter-rater reliability was excellent (intraclass correlation coefficient (ICC): 1.00, 95% confidence interval (CI) 1.00 - 1.00), as well as test-retest reliability (ICC: 0.91, 95% CI 0.80 - 0.96). CONCLUSION: The results found for convergent validity, inter-rater and test-retest reliability, showed that this version appears to be a valid and reliable instrument for evaluation of neuropsychiatric symptoms in institutionalized elderly.

Investigation of protein secretion and secretion stress in Ashbya gossypii.

BACKGROUND: Ashbya gossypii is a filamentous Saccharomycete used for the industrial production of riboflavin that has been recently explored as a host system for recombinant protein production. To gain insight into the protein secretory pathway of this biotechnologically relevant fungus, we undertook genome-wide analyses to explore its secretome and its transcriptional responses to protein secretion stress. RESULTS: A computational pipeline was used to predict the inventory of proteins putatively secreted by A. gossypii via the general secretory pathway. The proteins actually secreted by this fungus into the supernatants of submerged cultures in minimal and rich medium were mapped by two-dimensional gel electrophoresis, revealing that most of the A. gossypii secreted proteins have an isoelectric point between 4 and 6, and a molecular mass above 25 kDa. These analyses together indicated that 1-4% of A. gossypii proteins are likely to be secreted, of which less than 33% are putative hydrolases. Furthermore, transcriptomic analyses carried out in A. gossypii cells under recombinant protein secretion conditions and dithiothreitol-induced secretion stress unexpectedly revealed that a conventional unfolded protein response (UPR) was not activated in any of the conditions, as the expression levels of several well-known UPR target genes (e.g. IRE1, KAR2, HAC1 and PDI1 homologs) remained unaffected. However, several other genes involved in protein unfolding, endoplasmatic reticulum-associated degradation, proteolysis, vesicle trafficking, vacuolar protein sorting, secretion and mRNA degradation were up-regulated by dithiothreitol-induced secretion stress. Conversely, the transcription of several genes encoding secretory proteins, such as components of the glycosylation pathway, was severely repressed by dithiothreitol CONCLUSIONS: This study provides the first insights into the secretion stress response of A. gossypii, as well as a basic understanding of its protein secretion potential, which is more similar to that of yeast than to that of other filamentous fungi. Contrary to what has been widely described for yeast and fungi, a conventional UPR was not observed in A. gossypii, but alternative protein quality control mechanisms enabled it to cope with secretion stress. These data will help provide strategies for improving heterologous protein secretion in A. gossypii.

Ethical decision making in intensive care units: a burnout risk factor? Results from a multicentre study conducted with physicians and nurses.

BACKGROUND: Ethical decision making in intensive care is a demanding task. The need to proceed to ethical decision is considered to be a stress factor that may lead to burnout. The aim of this study is to explore the ethical problems that may increase burnout levels among physicians and nurses working in Portuguese intensive care units (ICUs). A quantitative, multicentre, correlational study was conducted among 300 professionals. RESULTS: The most crucial ethical decisions made by professionals working in ICU were related to communication, withholding or withdrawing treatments and terminal sedation. A positive relation was found between ethical decision making and burnout in nurses, namely, between burnout and the need to withdraw treatments (p=0.032), to withhold treatments (p=0.002) and to proceed to terminal sedation (p=0.005). This did not apply to physicians. Emotional exhaustion was the burnout subdimension most affected by the ethical decision. The nurses' lack of involvement in ethical decision making was identified as a risk factor. Nevertheless, in comparison with nurses (6%), it was the physicians (34%) who more keenly felt the need to proceed to ethical decisions in ICU. CONCLUSIONS: Ethical problems were reported at different levels by physicians and nurses. The type of ethical decisions made by nurses working in Portuguese ICUs had an impact on burnout levels. This did not apply to physicians. This study highlights the need for education in the field of ethics in ICUs and the need to foster inter-disciplinary discussion so as to encourage ethical team deliberation in order to prevent burnout.

Crohn's disease outcome in patients under azathioprine: a tertiary referral center experience.

BACKGROUND AND AIMS: Azathioprine is of major importance in the treatment of Crohn's disease; its efficacy has been showed in several works, but real-life data regarding its use is scarce. Our aim was to address the outcome of patients with Crohn's disease under azathioprine in the real-life setting. METHODS: Crohn's disease patients followed at an Inflammatory Bowel Disease Outpatient Clinic under azathioprine were consecutively enrolled, being allocated in one of four groups. Two groups included patients on treatment with this drug, regarding its two major indications - prevention of post-operative recurrence and steroid-dependent disease; a third group included patients who needed infliximab in addition to azathioprine and a fourth group comprised patients who did not tolerate azathioprine. RESULTS: A total of 221 patients were enrolled, 180 on azathioprine due to steroid-dependency (64 needing additional treatment with infliximab) and 41 for prevention of post-operative recurrence. Steroid-free remission was obtained in 48%. Immunosuppression decreased the number of hospitalized patients (64% vs 36%; p<0.001), but not the surgery rates per person per year. Azathioprine as a post-operative drug was effective in decreasing hospitalizations. The addition of infliximab decreased the number of patients hospitalized (p=0.009) and hospitalization rates per person per year (p<0.001), but had no effect in the surgery rates per person per year. Sixty patients (23%) experienced adverse effects with AZA, 39 requiring discontinuation of the drug. CONCLUSIONS: In this real-life study, azathioprine had a long-term steroid sparing effect and reduced hospitalizations. Combination with infliximab reduced hospitalizations but did not decrease the surgery rate.