Discontinuation of anti-tumor necrosis factor therapy in inflammatory bowel disease patients: a prospective observation

Background: Discontinuation of anti-TNF therapy in patients with inflammatory bowel diseases (IBD) in remission remains a controversial issue. The aims of our study were to assess the proportion of patients who relapse after cessation of biological treatment, and to identify potential risk factors of disease relapse. Methods: Consecutive IBD patients who discontinued anti-TNF therapy in steroid-free clinical and endoscopic remission were prospectively followed. Multiple logistic regression and Cox proportional-hazards models were used to assess the predictors of disease relapse. Results: Seventy-eight IBD patients (Crohn's disease, CD 61; ulcerative colitis, UC 17) were included and followed for a median of 30 months (range 7–47). A total of 32 (53%) CD patients and nine (53%) UC patients relapsed by the end of the follow-up with a median time to relapse of 8 months (range 1–25) in CD patients and 14 months (range 4–37) in UC patients, respectively. The cumulative probabilities of maintaining remission at 6, 12, and 24 months were 82%, 59%, and 51% in CD patients, and 77%, 77%, and 64% in UC patients, respectively. Survival of CD patients who were in deep remission (clinical and endoscopic healing; faecal calprotectin <150?mg/kg; CRP ≤5?mg/l) was not better compared with those who did not fulfill these criteria. In multivariate models, only colonic CD protected patients from disease relapse. Conclusions: Approximately half of the IBD patients relapsed within 2 years after anti-TNF discontinuation. In CD patients, no difference between those who were or were not in deep remission was found. Colonic localization protected patients from relapse.     

Mitochondria sentencing about cellular life and death: a matter of oxidative stress

Mitochondria are crucial, multifunctional organelles which actively regulate cellular homeostasis. Their complex and diverse role includes maintenance of the cellular energetic balance through hosting several catabolic pathways which result in the process of oxidative phosphorylation, as well as enabling various fundamental anabolic processes and controlling Ca2+ distribution. Moreover, mitochondria are the main cellular generator of reactive oxygen species, which act as second messengers and when over-produced provoke a state of oxidative stress, a condition implicated in many pathologies. Importantly, mitochondria are directly involved in triggering different and complexly interconnected programs promoting cell survival or death. The aim of this review is to summarize the current understanding regarding mitochondrial implication in the main cellular pathways controlling cell "fate" such as apoptosis, autophagy (mitophagy), mitoptosis and necrosis with particular emphasis on the role that reactive oxygen species and oxidative stress may play in these phenomena. The literature extensively covers the topic of reactive oxygen species and apoptosis, fewer articles however deal with mitophagy or mitochondrial dynamics and very few mention the implication oxidative stress and redox modifications have for mitoptosis or necrosis. This review offers a global picture of the complex role of mitochondria in the regulation of cell "fate", referring specifically to the interconnection and balance between different cellular pathways of death and survival. Current knowledge regarding the involvement of these processes in particular human pathologies, specifically with respect to the implication of reactive oxygen species and oxidative stress, is also discussed.     

Voriconazole Pharmacokinetics and Safety in Immunocompromised Children Compared to Adult Patients

The aim of this study was to investigate the pharmacokinetics and safety of voriconazole after intravenous (i.v.) administration in immunocompromised children (2 to 11 years old) and adults (20 to 60 years old) who required treatment for the prevention or therapy of systemic fungal infections. Nine pediatric patients were treated with a dose of 7 mg/kg i.v. every 12 h for a period of 10 days. Three children and 12 adults received two loading doses of 6 mg/kg i.v. every 12 h, followed by a maintenance dose of 5 mg/kg (children) or 4 mg/kg (adults) twice a day during the entire study period. Trough voriconazole levels in blood over 10 days of therapy and regular voriconazole levels in blood for up to 12 h postdose on day 3 were examined. Wide intra- and interindividual variations in plasma voriconazole levels were noted in each dose group and were most pronounced in the children receiving the 7-mg/kg dose. Five (56%) of them frequently had trough voriconazole levels in plasma below 1 μg/ml or above 6 μg/ml. The recommended dose of 7 mg/kg i.v. in children provides exposure (area under the concentration-time curve) comparable to that observed in adults receiving 4 mg/kg i.v. The children had significantly higher C_max values; other pharmacokinetic parameters were not significantly different from those of adults. Voriconazole exhibits nonlinear pharmacokinetics in the majority of children. Voriconazole therapy was safe and well tolerated in pediatric and adult patients. The European Medicines Agency-approved i.v. dose of 7 mg/kg can be recommended for children aged 2 to <12 years.Voriconazole (VRC) is an extended-spectrum triazole antifungal agent structurally derived from fluconazole with activity against a wide variety of yeasts and molds (4, 5, 8-11, 22). The drug is increasingly used in pediatric patients, but only a few studies have reported on the safety and pharmacokinetics of VRC in children (13, 19, 29, 30). These studies showed that there exist important pharmacokinetic differences between adults and children. VRC displays nonlinear pharmacokinetics in adults (14, 24, 25) but has linear pharmacokinetics in children receiving standard adult doses of 3 and 4 mg/kg every 12 h (30). The linearity was based on an 11-patient single-dose study of immunocompromised children (aged 2 to 11 years) and a 28-patient multiple-dose study of two age cohorts (2 to 6 and 6 to 11 years). Exposures were similar at 4 mg/kg in children and 3 mg/kg in adults. This observation likely reflects the higher elimination capacity of pediatric patients due to a greater ratio of liver mass to body mass than that of adults. To avoid clinical failures in children because of potentially subtherapeutic levels, higher per-kilogram doses of the drug are required in children to achieve exposures similar to those achieved in adults (26).In order to determine a dosing regimen that achieves comparable drug exposure levels in children and adults, a population pharmacokinetic analysis evaluated plasma VRC concentration-time data from a total of 82 patients aged 2 to <12 years. Data from the two above-mentioned studies (single and multiple doses of 3 and 4 mg/kg body weight) and data from a two-cohort, multiple-dose, intravenous (i.v.)-to-oral (p.o.) dosing switch study (4, 6, and 8 mg/kg body weight) were included in the analysis (13). Simulation outcomes suggest that exposure levels achieved with 7 mg/kg i.v. twice a day or 200 mg p.o. twice a day in pediatric patients aged 2 to <12 years are comparable to exposure levels observed in adult patients receiving approved dosing regimens. The dosage difference between adult and pediatric populations is a result of the different degrees of nonlinearity in VRC pharmacokinetics exhibited by the two groups. Due to a higher Michaelis-Menten constant in children than in adults, nonlinear elimination became principally apparent at higher doses for pediatric patients than for adults (13). In 2005, 3 years after preliminary approval by the European Union, new dosing recommendations for children aged 2 to <12 years (7 mg/kg i.v. twice a day or 200 mg p.o. twice a day) were established, despite the fact that this particular dose was not actually tested in the three pharmacokinetic studies that formed the basis of the simulation.In a retrospective study, a total of 207 VRC concentrations were measured in 46 children aged 0.8 to 20.5 years (19). Most (90%) of them received VRC p.o. (doses of 2.0 to 12.9 mg/kg body weight). Eight children received VRC i.v. (doses of 3.4 to 10.5 mg/kg body weight). Simulations predicted that an i.v. dose of 7 mg/kg or a p.o. dose of 200 mg twice daily would achieve a trough level of >1 μg/ml in most patients, but with a wide range of possible concentrations.We conducted an open-label, multicenter, parallel-group study to investigate the pharmacokinetics and safety profile of the parenteral formulation of VRC in immunocompromised children (aged 2 to <12 years) with a higher VRC dose per kg body weight than for adults (aged 20 to 60 years) with recommended dosing. We started to determine the plasma pharmacokinetics in pediatric patients with an i.v. dose of 5 mg/kg following the primary study protocol until October 2005 (n = 3) and after that with the newly European Medicines Agency(EMA)-approved i.v. dose of 7 mg/kg (n = 9).(This study was presented at the 50th annual German Society for Experimental and Clinical Pharmacology and Toxicology conference in Mainz, Germany, on 10 to 12 March 2009 [abstract 460].)     

The siRNA targeted to <Emphasis Type="Italic">mdr1b</Emphasis> and <Emphasis Type="Italic">mdr1a</Emphasis> mRNAs <Emphasis Type="Italic">in vivo</Emphasis>sensitizes murine lymphosarcoma to chemotherapy

Background  

One of the main obstacles for successful cancer polychemotherapy is multiple drug resistance phenotype (MDR) acquired by tumor cells. Currently, RNA interference represents a perspective strategy to overcome MDR via silencing the genes involved in development of this deleterious phenotype (genes of ABC transporters, antiapoptotic genes, etc.).     

Inactivation of nanocrystalline C60 cytotoxicity by gamma-irradiation

We investigated the effect of gamma-irradiation on the cytotoxicity of pure C60 solubilized in water by using tetrahydrofuran (THF/n-C60 or THF/n-C60). In contrast to THF/n-C60, its gamma-irradiated counterpart failed to generate oxygen radicals and cause extracellular signal-regulated kinase (ERK)-dependent necrotic cell death in various types of mammalian cells. Moreover, gamma-irradiated THF/n-C60 protected cells from the oxidative stress induced by native THF/n-C60 or hydrogen peroxide. The observed biological effects were associated with gamma-irradiation-mediated decomposition of THF and subsequent derivatization of the n-C60 surface. These results for the first time demonstrate gamma-irradiation-mediated changes in the physico-chemical properties of THF-prepared nanocrystalline C60, resulting in a complete loss of its cytotoxic effect and its conversion to a cytoprotective agent.     

Hypogalactosylation of salivary and gingival fluid immunoglobulin G in patients with advanced periodontitis

BACKGROUND: Altered glycosylation of immunoglobulin G (IgG) has been found to affect certain immunological activities of IgG and to correlate with increased inflammation in various disease states. This work deals with the changes in distribution and galactosylation of IgG subclasses present in saliva and gingival crevicular fluid (GCF) of patients with initial and advanced periodontitis and of normal controls. METHODS: IgG subclasses were quantified by dot-blot assay, and the degrees of expression of galactose in the total IgG and its individual subclasses were estimated by lectin immunoblot assay after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) separation of IgG and by capture enzyme-linked immunosorbent assay (ELISA), using biotinylated Ricinus communis (RCA-I) and Bandeiraea simplicifolia (BS-II) lectins. RESULTS: The distribution of IgG subclasses in both fluids was found to differ in periodontal patients compared to normal controls. In the periodontitis saliva and GCF, the IgG2 subclass dominated quantitatively, regardless of periodontal status. However, galactose was found to be expressed in IgG heavy chains in normal controls and patients with initial periodontitis but not, or at barely detectable levels, in advanced periodontitis. CONCLUSION: The results suggest that the shift toward hypogalactosylated glycoforms may occur during the process of inflammation of the gingiva.     

Phase-modulation laser interference microscopy: an advance in cell imaging and dynamics study

We describe how phase-modulation laser interference microscopy and wavelet analysis can be applied to noninvasive nonstained visualization and study of the structural and dynamical properties of living cells. We show how phase images of erythrocytes can reveal the difference between various erythrocyte forms and stages of hemolysis and how phase images of neurons reveal their complex intracellular structure. Temporal variations of the refractive index are analyzed to detect cellular rhythmic activity on different time scales as well as to uncover interactions between the cellular processes.     

Localization of N-type Ca2+ channels in the rat spinal cord following chronic constrictive nerve injury

Previous studies have shown that spinal L-type, N-type, and P-type Ca²⁺-channel blockers are effective in modulating pain behavior caused nerve injury. In the present work, using the loose ligation of the sciatic nerve model, we characterized the time course of the appearance of tactile and cold allodynia and the corresponding spinal expression of the N-type Ca²⁺ channel α_1B-subunit after nerve ligation. Within 1 week after ligation, the majority of rats developed a unilateral sensitivity to mechanical stimulation (von Frey filaments), as well as sensitivity to cold, which persisted for 30 days. Immunocytochemical analysis of the spinal cord in sham-operated animals for the α_1B-subunit showed a smooth, moderate staining pattern in the superficial laminae I–II, as well as in ventral α-motoneurons. In nerve-ligated animals, an intense, dot-like immunoreactivity in the ipsilateral dorsal horn was observed from 5–20 days after nerve ligation. The most prominent α_1B-subunit upregulation was found in the outer as well as the inner part of lamina II (II_o, II_i), extending from the medial toward the lateral region of the L4 and L5 spinal segments. The behavioral changes which developed after chronic constriction injury directly correlated with the α_1B-subunit upregulation in the corresponding spinal cord segments. These data suggest that upregulation of the spinal α_1B-subunit may play an important role in the initiation and maintenance of pain state after peripheral nerve injury. Electronic Publication     

Primary malignant mesothelioma of the peritoneum

Mesothelioma of the peritoneum represents an extremely rare malignancy of the abdominal cavity and forms about 10% of all mesotheliomas. The annual incidence of the tumor in the general population is 1-2 cases per million. The causative relationship between chronic exposure to asbestos and mesothelioma has been proved. Since the symptomatology of the tumor is usually not specific, the diagnosis is made in the advanced stages of the disease, which is the limiting factor for therapy. Most patients die within 2 years from the diagnosis. We report a case of a primary malignant mesothelioma of the peritoneum in a 60-year old male, who presented with three-month history of ascites, weakness and appetite loss. The patient gave the information that he had been living for 15 years in a loft which was insulated by material consisting of asbestos. After investigations, primary neoplasm of the peritoneum was suspected, which was confirmed by the biopsy and the morphopathological examination. Due to the advanced spread of the tumor and the poor general condition, the patient underwent palliative therapy. The patient died 3 months after the diagnosis. Epidemiological data for chronic exposure to asbestos have to be considered as the etiological factor of disease in this particular patient.