Frataxin participates to the hypoxia-induced response in tumors.

Defective expression of frataxin is responsible for the degenerative disease Friedreich's ataxia. Frataxin is a protein required for cell survival since complete knockout is lethal. Frataxin protects tumor cells against oxidative stress and apoptosis but also acts as a tumor suppressor. The molecular bases of this apparent paradox are missing. We therefore sought to investigate the pathways through which frataxin enhances stress resistance in tumor cells. We found that frataxin expression is upregulated in several tumor cell lines in response to hypoxic stress, a condition often associated with tumor progression. Moreover, frataxin upregulation in response to hypoxia is dependent on hypoxia-inducible factors expression and modulates the activation of the tumor-suppressor p53. Importantly, we show for the first time that frataxin is in fact increased in human tumors in vivo. These results show that frataxin participates to the hypoxia-induced stress response in tumors, thus implying that modulation of its expression could have a critical role in tumor cell survival and/or progression.

Interleukin-25 production is differently regulated by TNF-α and TGF-ß1 in the human gut.

An altered balance between effector and regulatory factors is supposed to sustain the tissue-damaging immune response in inflammatory bowel disease (IBD). We have recently shown that in IBD, there is a defective synthesis of the counter-regulatory cytokine, interleukin (IL)-25. In this study we investigated factors that control IL-25 production in the gut. IBD patients produced less IL-25 when compared with normal controls. Stimulation of normal intestinal explants with tumor necrosis factor-α (TNF-α), but not interferon-γ (IFN-γ) or IL-21, reduced IL-25 synthesis. Consistently, IL-25 production was enhanced by anti-TNF-α both in vitro and in vivo. Upregulation of IL-25 was also seen in normal colonic explants stimulated with transforming growth factor-ß1 (TGF-ß1). As in IBD, TGF-ß1 activity is abrogated by Smad7, we next assessed whether inhibition of Smad7 with an antisense oligonucleotide enhanced IL-25 expression. Knockdown of Smad7 was accompanied by an increase in IL-25 production. Data show that IL-25 production is differently regulated by TNF-α and TGF-ß1 in the human gut.

Transcriptional and post-translational regulation of Flip, an inhibitor of Fas-mediated apoptosis, in human gut inflammation.

OBJECTIVE: Defects in Fas-mediated apoptosis are supposed to contribute to the accumulation of T lymphocytes in the gut of patients with Crohn's disease (CD). This phenomenon has been functionally linked with the elevated expression of Flip, an inhibitor of Fas-mediated apoptosis. In this study, the molecular mechanisms that control Flip in CD were examined. METHODS: Paired colonic biopsies of patients with CD, patients with ulcerative colitis (UC) and normal controls were analysed for Flip by real-time PCR and western blotting. Flip was also evaluated in CD3(+) lamina propria lymphocytes (T-LPLs) cultured with tosyl phenylalanyl chloromethyl ketone (TPCK; a nuclear factor-kappaB (NF-kappaB) inhibitor), AG490 (a Janus kinase 2 (Jak2)/signal transducer and activator of transcription (Stat) inhibitor) or 17-desmethoxy-17-N,N-dimethylamino-geldanamycin (DMAG; an inhibitor of heat shock protein 90). The rate of apoptosis was examined by flow cytometry. RESULTS: In CD, upregulation of Flip occurred at both the RNA and protein level. Treatment of CD CD3(+) T-LPLs with TPCK or AG490 markedly reduced Flip RNA, suggesting a role for NF-kappaB and Jak/Stat pathways in the transcriptional control of Flip in this condition. Consistently, both TPCK and AG490 sensitised CD T-LPLs to Fas-mediated apoptosis. Flip protein in cells from normal gut was rapidly degraded by the proteasome pathway. In contrast, in inflamed gut of both CD and UC patients, there was a reduced degradation of Flip via the ubiquitin-proteasome-dependent pathway, but Flip expression can be decreased by DMAG. CONCLUSIONS: The data demonstrate that Flip is regulated at both the transcriptional and post-translational level in CD, and indicate that in the normal but not inflamed gut Flip is degraded via the ubiquitin-proteasome-dependent pathway.

Interleukin 21 contributes to the mucosal T helper cell type 1 response in coeliac disease.

BACKGROUND: In coeliac disease (CD), the upper bowel lesion is associated with a marked infiltration of the mucosa with Th1 cells secreting interferon gamma (IFNgamma) and expressing the Th1-associated transcription factor, T-bet. However, the molecular mechanisms which regulate T-bet and promote the Th1 cell response are unknown. OBJECTIVE: To examine whether interleukin 21 (IL21), a cytokine that regulates T cell activation, has a role in CD. METHODS: Duodenal mucosal samples were taken from CD patients and normal controls. IL21 and T-bet were examined by real-time PCR and western blotting, and IFNgamma was assessed by real-time PCR and ELISA. The effect of blockade of endogenous IL21 on the expression of T-bet was examined in an ex vivo culture of biopsies taken from untreated CD patients. Finally, the role of IL21 in controlling T-bet and IFNgamma was also evaluated in cultures of biopsies taken from treated CD patients and cultured with a peptic-tryptic digest of gliadin (PT) in the presence or absence of a neutralising IL21 antibody. RESULTS: Enhanced IL21 RNA and protein expression was seen in duodenal samples from untreated CD patients. Blockade of IL21 activity in biopsies of untreated CD patients reduced T-bet and IFNgamma secretion. Stimulation of treated CD biopsies with PT enhanced IL21 expression, and neutralisation of IL21 largely prevented PT-driven T-bet and IFNgamma induction. CONCLUSIONS: IL21 is overproduced in the mucosa of CD patients, where it helps sustain T-bet expression and IFNgamma production.

Control of matrix metalloproteinase production in human intestinal fibroblasts by interleukin 21.

BACKGROUND: T cell-mediated immunity plays a central part in the pathogenesis of tissue damage in inflammatory bowel disease (IBD). The mechanism by which T cells mediate tissue damage during IBD remains unclear, but evidence indicates that T cell-derived cytokines stimulate fibroblasts to synthesise matrix metalloproteinases (MMPs), which then mediate mucosal degradation. We have previously shown that, in IBD, there is high production of interleukin (IL) 21, a T cell-derived cytokine, which enhances Th1 activity. AIM: To investigate whether IL21 controls MMP production by intestinal fibroblasts. METHODS: IL21 receptor (IL21R) was evaluated in intestinal fibroblasts by reverse transcriptase-polymerase chain reaction (RT-PCR) and western blotting. Fibroblasts were stimulated with IL21 and MMPs were evaluated by RT-PCR and western blotting. The effect of a neutralising IL21R fusion protein (IL21R/Fc) on the induction of MMPs in fibroblasts stimulated with IBD lamina propria mononuclear cell (LPMC) supernatants was also evaluated. RESULTS: Intestinal fibroblasts constitutively express both IL21R and the common gamma chain receptor, which are necessary for IL21-driven signalling. IL21 enhances fibroblast production of MMP-1, MMP-2, MMP-3 and MMP-9, but not tissue inhibitors of MMP-1 and MMP-2. Moreover, IL21 synergises with tumour necrosis factor alpha to increase synthesis of MMP synthesis. IL21 enhances MMP secretion without affecting gene transcription and protein synthesis. IBD LPMC supernatants stimulate MMP secretion by intestinal fibroblasts, and this effect is partly inhibited by IL21R/Fc. CONCLUSIONS: These results suggest that fibroblasts are a potential target of IL21 in the gut and that IL21 controls MMP secretion by fibroblasts.

Silencing of SH-PTP2 defines a crucial role in the inactivation of epidermal growth factor receptor by 5-aminosalicylic acid in colon cancer cells.

Recent studies have suggested that 5-aminosalicylic acid (5-ASA) inhibits colorectal cancer (CRC) development. However, the mechanism underlying the antineoplastic effect of 5-ASA remains unknown. We here examined the effect of 5-ASA on epidermal growth factor receptor (EGFR) activation, a pathway that triggers mitogenic signals in CRC cells. We show that 5-ASA inhibits EGFR activation, through a mechanism that does not rely on CRC cell death induction. 5-ASA enhances the activity, but not expression, of phosphorylated (p)-EGFR-targeting phosphatases (PTPs), and treatment of cells with PTP inhibitors abrogates the 5-ASA-mediated EGFR dephosphorylation. Both SH-PTP1 and SH-PTP2 interact with EGFR upon 5-ASA treatment. However, knockdown of SH-PTP2 but not SH-PTP1 by small interference RNAs prevents the 5-ASA-induced EGFR dephosphorylation. Finally, we show that 5-ASA attenuates p-EGFR in ex vivo organ cultures of CRC explants. Data indicate that 5-ASA disrupts EGFR signalling by enhancing SH-PTP2 activity, and suggest a mechanism by which 5-ASA interferes with CRC growth.

Technetium-99m-HMPAO labeled leukocyte single photon emission computerized tomography (SPECT) for assessing Crohn's disease extent and intestinal infiltration.

OBJECTIVES: Scintigraphy using radiolabeled leukocytes is a useful technique for assessing intestinal infiltration in Crohn's disease (CD). However, limits of planar images include overlapping activity in other organs and low specificity. To investigate the usefulness of (99m)Tc-HMPAO (hexametyl propylene amine oxime) labeled leukocyte single photon emission computerized tomography (SPECT) for assessing CD lesions, in comparison with planar images. METHODS: Twenty-two inflammatory bowel disease patients (19 CD; 2 ulcerative colitis, UC; 1 ileal pouch) assessed by conventional endoscopy or radiology were enrolled. Leukocytes were labeled with (99m)Tc-HMPAO. SPECT images were acquired at 2 h and planar images at 30 min and 2 h. Bowel uptake was quantitated in nine regions (score 0-3). RESULTS: Both SPECT and planar images detected a negative scintigraphy (score 0) in the UC patient with no pouchitis and a positive scintigraphy (score 1-3) in the 21 patients showing active inflammation by conventional techniques. SPECT showed a higher global score than planar images (0.71 +/- 0.09 vs 0.30 +/- 0.05; p < 0.001), and in particular in the right iliac fossa (p= 0.003), right and left flank (p < 0.001; p= 0.02), hypogastrium (p= 0.002), and mesogastrium (p < 0.001). SPECT provided a better visualization and a higher uptake than planar images in patients with ileal and ileocolonic CD (6.45 +/- 0.82 vs 2.8 +/- 0.55, p < 0.001; 5.5 +/- 1.6 vs 2.6 +/- 0.7, p= 0.03), and with perianal CD (6.6 +/- 1.6 vs 3.4 +/- 1.2; p= 0.03). CONCLUSIONS: (99m)Tc-HMPAO labeled leukocyte SPECT provides a more detailed visualization of CD lesions than planar images. This technique may better discriminate between intestinal and bone marrow uptake, thus being useful for assessing CD lesions within the pelvis, including perianal disease.

Rofecoxib and early relapse of inflammatory bowel disease: an open-label trial.

BACKGROUND: The safety and efficacy of selective cyclo-oxygenase-2 inhibitors in inflammatory bowel disease are under investigation. AIM: To assess, in a prospective, open-label trial, the efficacy and safety of rofecoxib (12.5 mg/day) in inflammatory bowel disease patients and controls. METHODS: The inflammatory bowel disease group included 45 inactive patients (25 Crohn's disease; 20 ulcerative colitis) with associated arthralgia. The control group included 30 dyspeptic patients. The efficacy and safety of rofecoxib were assessed in inflammatory bowel disease patients and controls before and after treatment (range, 3 days to 3 months). RESULTS: In inflammatory bowel disease, nine of the 45 patients (20%) required rofecoxib withdrawal due to gastrointestinal symptoms inducing clinical relapse, which subsided on drug discontinuation. The percentage of patients requiring rofecoxib discontinuation was comparable in patients with Crohn's disease and ulcerative colitis (20% vs. 20%), but was higher in inflammatory bowel disease patients than in controls (20% vs. 3%; P < 0.001). In inflammatory bowel disease, arthralgia relief was reported by 32 patients (71%): complete relief by eight patients (18%) and partial relief by 24 (53%). Thirteen patients (29%) reported no benefit. A comparable percentage of inflammatory bowel disease patients and controls reported arthralgia relief (71% vs. 70%). CONCLUSIONS: Rofecoxib appears to control arthralgia in almost two-thirds of inflammatory bowel disease patients. Side-effects requiring drug discontinuation are observed, however, in almost one-quarter of patients.

Review article: maintenance treatment of Crohn's disease.

The aetiology of Crohn's disease is unknown and therefore no curative treatments are available for the disease. The natural history of Crohn's disease is characterized by recurrent flare-ups of symptoms. Several drug treatments are effective in inducing clinical remission. However, no drug treatments are available in order to prevent clinical relapses, although several drug regimens may delay clinical flare-ups. Crohn's disease treatment for maintaining clinical remission needs to be tailored in relation to specific characteristics of each patient. The frequency of clinical relapse indeed shows marked variations in subgroups of patients, as the likelyhood of relapse is higher in patients in clinical remission for less than 6 months. Treatment strategies for maintaining remission may therefore differ among inactive patients. In chronically active, steroid-dependent or steroid-refractory Crohn's disease patients immunomodulatory drugs (azathioprine 2-2.5 mg/kg by mouth, 6-mercaptopurine 1-1.5 mg/kg by mouth, or methotrexate 15-25 mg/i.m./week) should be added to oral mesalazine (2.4 g/day), while in long-term inactive Crohn's disease patients mesalazine alone may be effective in delaying relapse. Recently, treatment with anti-tumour necrosis factor-alpha monoclonal antibodies (Infliximab or CDP571) has shown efficacy in delaying relapse in responsive patients. One other issue which needs to be considered before selecting drug treatments for maintaining remission in Crohn's disease, is that Crohn's disease activity is currently assessed on the basis of standard clinical scores which may not appropriately reflect the biological activity of the disease. Clinical remission as defined by standardized scores may include heterogeneous subgroups of patients showing different endoscopic and histological activity or persistence of activated immunocompetent cells within the gut. Several sub-clinical markers of relapse have indeed been reported in quiescent Crohn's disease, although their usefulness in clinical practice in currently uncertain.

Parent participation in the postanesthesia care unit: fourteen years of progress at one hospital.

Parent participation in postanesthesia nursing practice was instituted in 1983 at Boston's Children's Hospital as part of a continuing emphasis on family participation in the care of hospitalized children throughout the hospital. This report describes the evolution and implementation of this practice. The success of this program is supported by data from quality improvement monitors of the comfort levels of PACU patients before and after their parents were invited to the bedside. Quality improvement monitors of parent satisfaction with involvement in their child's care were also conducted. Nursing exemplars illustrate parental and nursing responses to this program.

The spiritual needs of pediatric patients and their families.

Holistic perioperative nursing care of children and their families includes assessing their spiritual needs and identifying interventions that help them achieve spiritual comfort. This is achieved by therapeutic listening and by facilitating children's and family members' access to clergy members of their practice of religious rites and rituals. Perioperative nurses have a unique opportunity and responsibility to assess children's or family members' spiritual needs and to intervene on their behalf. This article describes the opportunities a surgical liaison nurse may have to intervene on the behalf of family members during children's perioperative experiences.

Ototoxicity of gentamicin: clinical experience in a children's hospital.

In a effort to estimate the incidence of clinical ototoxicity in children we reviewed the charts of 374 patients who had serum gentamicin concentration determined 30 min before ('trough value') and at the pharmacologic peak after parenteral administration. 37 of these patients, between 9 and 17 years of age, had two or more audiograms; of these, 9 developed objective evidence of hearing loss; in 2 the impairment was severe and permanent. Risk factors associated with ototoxicity were renal failure, concomitant administration of diuretics and peak serum concentrations greater than 12 microgram/ml (all significant at p less than 0.01). The minimum incidence of overt hearing loss secondary to gentamicin therapy is approximately 2.4%.