901 resultados para Gastrointestinal parasites
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This Guideline is an official statement of the European Society of Gastrointestinal Endoscopy (ESGE). It addresses the diagnosis and management of nonvariceal upper gastrointestinal hemorrhage (NVUGIH). Main Recommendations MR1. ESGE recommends immediate assessment of hemodynamic status in patients who present with acute upper gastrointestinal hemorrhage (UGIH), with prompt intravascular volume replacement initially using crystalloid fluids if hemodynamic instability exists (strong recommendation, moderate quality evidence). MR2. ESGE recommends a restrictive red blood cell transfusion strategy that aims for a target hemoglobin between 7 g/dL and 9 g/dL. A higher target hemoglobin should be considered in patients with significant co-morbidity (e. g., ischemic cardiovascular disease) (strong recommendation, moderate quality evidence). MR3. ESGE recommends the use of the Glasgow-Blatchford Score (GBS) for pre-endoscopy risk stratification. Outpatients determined to be at very low risk, based upon a GBS score of 0 - 1, do not require early endoscopy nor hospital admission. Discharged patients should be informed of the risk of recurrent bleeding and be advised to maintain contact with the discharging hospital (strong recommendation, moderate quality evidence). MR4. ESGE recommends initiating high dose intravenous proton pump inhibitors (PPI), intravenous bolus followed by continuous infusion (80 mg then 8 mg/hour), in patients presenting with acute UGIH awaiting upper endoscopy. However, PPI infusion should not delay the performance of early endoscopy (strong recommendation, high quality evidence). MR5. ESGE does not recommend the routine use of nasogastric or orogastric aspiration/lavage in patients presenting with acute UGIH (strong recommendation, moderate quality evidence). MR6. ESGE recommends intravenous erythromycin (single dose, 250 mg given 30 - 120 minutes prior to upper gastrointestinal [GI] endoscopy) in patients with clinically severe or ongoing active UGIH. In selected patients, pre-endoscopic infusion of erythromycin significantly improves endoscopic visualization, reduces the need for second-look endoscopy, decreases the number of units of blood transfused, and reduces duration of hospital stay (strong recommendation, high quality evidence). MR7. Following hemodynamic resuscitation, ESGE recommends early (≤ 24 hours) upper GI endoscopy. Very early (< 12 hours) upper GI endoscopy may be considered in patients with high risk clinical features, namely: hemodynamic instability (tachycardia, hypotension) that persists despite ongoing attempts at volume resuscitation; in-hospital bloody emesis/nasogastric aspirate; or contraindication to the interruption of anticoagulation (strong recommendation, moderate quality evidence). MR8. ESGE recommends that peptic ulcers with spurting or oozing bleeding (Forrest classification Ia and Ib, respectively) or with a nonbleeding visible vessel (Forrest classification IIa) receive endoscopic hemostasis because these lesions are at high risk for persistent bleeding or rebleeding (strong recommendation, high quality evidence). MR9. ESGE recommends that peptic ulcers with an adherent clot (Forrest classification IIb) be considered for endoscopic clot removal. Once the clot is removed, any identified underlying active bleeding (Forrest classification Ia or Ib) or nonbleeding visible vessel (Forrest classification IIa) should receive endoscopic hemostasis (weak recommendation, moderate quality evidence). MR10. In patients with peptic ulcers having a flat pigmented spot (Forrest classification IIc) or clean base (Forrest classification III), ESGE does not recommend endoscopic hemostasis as these stigmata present a low risk of recurrent bleeding. In selected clinical settings, these patients may be discharged to home on standard PPI therapy, e. g., oral PPI once-daily (strong recommendation, moderate quality evidence). MR11. ESGE recommends that epinephrine injection therapy not be used as endoscopic monotherapy. If used, it should be combined with a second endoscopic hemostasis modality (strong recommendation, high quality evidence). MR12. ESGE recommends PPI therapy for patients who receive endoscopic hemostasis and for patients with adherent clot not receiving endoscopic hemostasis. PPI therapy should be high dose and administered as an intravenous bolus followed by continuous infusion (80 mg then 8 mg/hour) for 72 hours post endoscopy (strong recommendation, high quality evidence). MR13. ESGE does not recommend routine second-look endoscopy as part of the management of nonvariceal upper gastrointestinal hemorrhage (NVUGIH). However, in patients with clinical evidence of rebleeding following successful initial endoscopic hemostasis, ESGE recommends repeat upper endoscopy with hemostasis if indicated. In the case of failure of this second attempt at hemostasis, transcatheter angiographic embolization (TAE) or surgery should be considered (strong recommendation, high quality evidence). MR14. In patients with NVUGIH secondary to peptic ulcer, ESGE recommends investigating for the presence of Helicobacter pylori in the acute setting with initiation of appropriate antibiotic therapy when H. pylori is detected. Re-testing for H. pylori should be performed in those patients with a negative test in the acute setting. Documentation of successful H. pylori eradication is recommended (strong recommendation, high quality evidence). MR15. In patients receiving low dose aspirin for secondary cardiovascular prophylaxis who develop peptic ulcer bleeding, ESGE recommends aspirin be resumed immediately following index endoscopy if the risk of rebleeding is low (e. g., FIIc, FIII). In patients with high risk peptic ulcer (FIa, FIb, FIIa, FIIb), early reintroduction of aspirin by day 3 after index endoscopy is recommended, provided that adequate hemostasis has been established (strong recommendation, moderate quality evidence).
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PURPOSE: Malignant ascites is debilitating for patients with advanced cancer. As shown previously, tumour cell production of vascular endothelial growth factor might be a major cause of the formation of malignant ascites. Intraperitoneal bevacizumab could therefore be an option for symptom control in refractory ascites. PATIENTS AND METHODS: Patients with advanced gastrointestinal cancer and malignant ascites who had undergone paracentesis at least twice within the past 4 weeks were randomly assigned in a 2:1 ratio to intraperitoneal bevacizumab (400 mg absolute) or placebo after paracentesis. During the 8-week treatment period, a minimum interval of 14 d was kept between the applications of the study drug. Primary end-point was paracentesis-free survival (ParFS). RESULTS: Fifty-three patients (median age 63 years) were randomised. Forty-nine patients received at least one study drug application and qualified for the main analysis. The proportion of patients with at least one common toxicity criteria grade III-V event was similar with 20/33 (61%) on bevacizumab and 11/16 (69%) on placebo. Median ParFS was 14 d (95% confidence interval [CI]: 11-17) in the bevacizumab arm and 10.5 d (95% CI: 7-21) on placebo (hazard ratio 0.74, 95% CI: 0.40-1.37; P = 0.16). The longest paracentesis-free period was 19 d on bevacizumab (range 6-66 d) and 17.5 d in the placebo arm (range 4-42) (P = 0.85). Median overall survival was 64 d (95% CI: 45-103) on bevacizumab compared to 31.5 d (95% CI: 20-117) on placebo (P = 0.31). CONCLUSION: Intraperitoneal bevacizumab was well tolerated. Overall, treatment did not result in a significantly better symptom control of malignant ascites. However, patients defined by specific immune characteristics may benefit.
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Primary treatment of rectal cancer was the focus of the second St. Gallen European Organisation for Research and Treatment of Cancer (EORTC) Gastrointestinal Cancer Conference. In the context of the conference, a multidisciplinary international expert panel discussed and voted on controversial issues which could not be easily answered using published evidence. Main topics included optimal pretherapeutic imaging, indication and type of neoadjuvant treatment, and the treatment strategies in advanced tumours. Here we report the key recommendations and summarise the related evidence. The treatment strategy for localised rectal cancer varies from local excision in early tumours to neoadjuvant radiochemotherapy (RCT) in combination with extended surgery in locally advanced disease. Optimal pretherapeutic staging is a key to any treatment decision. The panel recommended magnetic resonance imaging (MRI) or MRI + endoscopic ultrasonography (EUS) as mandatory staging modalities, except for early T1 cancers with an option for local excision, where EUS in addition to MRI was considered to be most important because of its superior near-field resolution. Primary surgery with total mesorectal excision was recommended by most panellists for some early tumours with limited risk of recurrence (i.e. cT1-2 or cT3a N0 with clear mesorectal fascia on MRI and clearly above the levator muscles), whereas all other stages were considered for multimodal treatment. The consensus panel recommended long-course RCT over short-course radiotherapy for most clinical situations where neoadjuvant treatment is indicated, with the exception of T3a/b N0 tumours where short-course radiotherapy or even no neoadjuvant therapy were regarded to be an option. In patients with potentially resectable tumours and synchronous liver metastases, most panel members did not see an indication to start with classical fluoropyrimidine-based RCT but rather favoured preoperative short-course radiotherapy with systemic combination chemotherapy or alternatively a liver-first resection approach in resectable metastases, which both allow optimal systemic therapy for the metastatic disease. In general, proper patient selection and discussion in an experienced multidisciplinary team was considered as crucial component of care.
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BACKGROUND: Treatment of patients with severe liver dysfunction including hyperbilirubinemia secondary to liver metastases of gastrointestinal (GI) cancer is challenging. Regimen of oxaliplatin and fluoropyrimidine (FP)/folinic acid (FA) ± a monoclonal antibody (moAb), represents a feasible option considering the pharmacokinetics. Clinical data on the respective dosage and tolerability are limited and no recommendations are available. METHODS: Consecutive patients with severe hyperbilirubinemia [>2 × upper limit of the normal range (ULN) and >2.4 mg/dl] due to liver metastases of GI cancer without options for drainage receiving oxaliplatin, FP/FA ± moAb were analyzed. To collect further data a review of the literature was performed. RESULTS: A total of 12 patients were identified between 2011 and 2015. At treatment start, median bilirubin level was 6.1 mg/dl (>5 × ULN, range 2.7-13.6). The majority of patients (n = 11) received dose-reduced regimen with oxaliplatin (60-76%) and FP/FA (0-77%), rapidly escalating to full dose regimen. During treatment, bilirubin levels dropped more than 50% within 8 weeks or normalized within 12 weeks in 6 patients (responders). Median overall survival was 5.75 months (range 1.0-16.0 months) but was significantly prolonged in responders compared to nonresponders [9.7 and 3.0 months, p = 0.026 (two-sided test); 95% confidence interval (CI): 1.10-10.22]. In addition, case reports or series comprising a further 26 patients could be identified. Based on the obtained data a treatment algorithm was developed. CONCLUSION: Treatment with oxaliplatin, FP/FA ± moAb is feasible and may derive relevant benefits in patients with severe liver dysfunction caused by GI cancer liver metastases without further options of drainage.
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BACKGROUND Gastrointestinal and respiratory diseases in calves and piglets lead to significant economic losses in livestock husbandry. A high morbidity has been reported for diarrhea (calves ≤ 35 %; piglets ≤ 50 %) and for respiratory diseases (calves ≤ 80 %; piglets ≤ 40 %). Despite a highly diverse etiology and pathophysiology of these diseases, treatment with antimicrobials is often the first-line therapy. Multi-antimicrobial resistance in pathogens results in international accordance to strengthen the research in novel treatment options. Medicinal plants bear a potential as alternative or additional treatment. Based on the versatile effects of their plant specific multi-component-compositions, medicinal plants can potentially act as 'multi-target drugs'. Regarding the plurality of medicinal plants, the aim of this systematic review was to identify potential medicinal plant species for prevention and treatment of gastrointestinal and respiratory diseases and for modulation of the immune system and inflammation in calves and piglets. RESULTS Based on nine initial sources including standard textbooks and European ethnoveterinary studies, a total of 223 medicinal plant species related to the treatment of gastrointestinal and respiratory diseases was identified. A defined search strategy was established using the PRISMA statement to evaluate 30 medicinal plant species starting from 20'000 peer-reviewed articles published in the last 20 years (1994-2014). This strategy led to 418 references (257 in vitro, 84 in vivo and 77 clinical trials, thereof 48 clinical trials in veterinary medicine) to evaluate effects of medicinal plants and their efficacy in detail. The findings indicate that the most promising candidates for gastrointestinal diseases are Allium sativum L., Mentha x piperita L. and Salvia officinalis L.; for diseases of the respiratory tract Echinacea purpurea (L.) MOENCH, Thymus vulgaris L. and Althea officinalis L. were found most promising, and Echinacea purpurea (L.) MOENCH, Camellia sinensis (L.) KUNTZE, Glycyrrhiza glabra L. and Origanum vulgare L. were identified as best candidates for modulation of the immune system and inflammation. CONCLUSIONS Several medicinal plants bear a potential for novel treatment strategies for young livestock. There is a need for further research focused on gastrointestinal and respiratory diseases in calves and piglets, and the findings of this review provide a basis on plant selection for future studies.
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Plasmodium and Theileria parasites are obligate intracellular protozoa of the phylum Apicomplexa. Theileria infection of bovine leukocytes induces transformation of host cells and infected leukocytes can be kept indefinitely in culture. Theileria-dependent host cell transformation has been the subject of interest for many years and the molecular basis of this unique phenomenon is quite well understood. The equivalent life cycle stage of Plasmodium is the infection of mammalian hepatocytes, where parasites reside for 2-7 days depending on the species. Some of the molecular details of parasite-host interactions in P. berghei-infected hepatocytes have emerged only very recently. Similar to what has been shown for Theileria-infected leukocytes these data suggest that malaria parasites within hepatocytes also protect their host cell from programmed cell death. However, the strategies employed to inhibit host cell apoptotic pathways appear to be different to those used by Theileria. This review discusses similarities and differences at the molecular level of Plasmodium- and Theileria-induced regulation of the host cell survival machinery.
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Apicomplexan parasites of the genera Theileria and Plasmodium have complicated life cycles including infection of a vertebrate intermediate host and an arthropod definitive host. As the Plasmodium parasite progresses through its life cycle, it enters a number of different cell types, both in its mammalian and mosquito hosts. The fate of these cells varies greatly, as do the parasite and host molecules involved in parasite-host interactions. In mammals, Plasmodium parasites infect hepatocytes and erythrocytes whereas Theileria infects ruminant leukocytes and erythrocytes. Survival of Plasmodium-infected hepatocytes and Theileria-infected leukocytes depends on parasite-mediated inhibition of host cell apoptosis but only Theileria-infected cells exhibit a fully transformed phenotype. As the development of both parasites progresses towards the merozoite stage, the parasites no longer promote the survival of the host cell and the infected cell is finally destroyed to release merozoites. In this review we describe similarities and differences of parasite-host cell interactions in Plasmodium-infected hepatocytes and Theileria-infected leukocytes and compare the observed phenotypes to other parasite stages interacting with host cells.
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The intracellular stages of apicomplexan parasites are known to extensively modify their host cells to ensure their own survival. Recently, considerable progress has been made in understanding the molecular details of these parasite-dependent effects for Plasmodium-, Toxoplasma- and Theileria-infected cells. We have begun to understand how Plasmodium liver stage parasites protect their host hepatocytes from apoptosis during parasite development and how they induce an ordered cell death at the end of the liver stage. Toxoplasma parasites are also known to regulate host cell survival pathways and it has been convincingly demonstrated that they block host cell major histocompatibility complex (MHC)-dependent antigen presentation of parasite epitopes to avoid cell-mediated immune responses. Theileria parasites are the masters of host cell modulation because their presence immortalises the infected cell. It is now accepted that multiple pathways are activated to induce Theileria-dependent host cell transformation. Although it is now known that similar host cell pathways are affected by the different parasites, the outcome for the infected cell varies considerably. Improved imaging techniques and new methods to control expression of parasite and host cell proteins will help us to analyse the molecular details of parasite-dependent host cell modifications.
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Protein degradation is regulated during the cell cycle of all eukaryotic cells and is mediated by the ubiquitin-proteasome pathway. Potent and specific peptide-derived inhibitors of the 20S proteasome have been developed recently as anti-cancer agents, based on their ability to induce apoptosis in rapidly dividing cells. Here, we tested a novel small molecule dipeptidyl boronic acid proteasome inhibitor, named MLN-273 on blood and liver stages of Plasmodium species, both of which undergo active replication, probably requiring extensive proteasome activity. The inhibitor blocked Plasmodium falciparum erythrocytic development at an early ring stage as well as P. berghei exoerythrocytic progression to schizonts. Importantly, neither uninfected erythrocytes nor hepatocytes were affected by the drug. MLN-273 caused an overall reduction in protein degradation in P. falciparum, as demonstrated by immunoblots using anti-ubiquitin antibodies to label ubiquitin-tagged protein conjugates. This led us to conclude that the target of the drug was the parasite proteasome. The fact that proteasome inhibitors are presently used as anti-cancer drugs in humans forms a solid basis for further development and makes them potentially attractive drugs also for malaria chemotherapy.
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The generation of rodent Plasmodium strains expressing fluorescent proteins in all life cycle stages has had a big impact on malaria research. With this tool in hand, for the first time it was possible to follow in real time by in vivo microscopy the infection route of Plasmodium sporozoites transmitted to the mammalian host by Anopheles mosquitoes. Recently, this work has been extended to the analysis of both hepatocyte infection by Plasmodium sporozoites, as well as liver merozoite transport into blood vessels. The stunning results of these studies have considerably changed our understanding of hepatocyte invasion and parasite liberation. Here, we describe the most important findings of the last years and in addition, we elaborate on the molecular events during the intracellular development of Plasmodium exoerythrocytic forms that give rise to erythrocyte infecting merozoites.
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The rodent malaria parasite Plasmodium berghei develops in hepatocytes within 48-52h from a single sporozoite into up to 20,000 daughter parasites, so-called merozoites. The cellular and molecular details of this extensive proliferation are still largely unknown. Here we have used a transgenic, RFP-expressing P. berghei parasite line and molecular imaging techniques including intravital microscopy to decipher various aspects of parasite development within the hepatocyte. In late schizont stages, MSP1 is expressed and incorporated into the parasite plasma membrane that finally forms the membrane of developing merozoites by continuous invagination steps. We provide first evidence for activation of a verapamil-sensitive Ca(2+) channel in the plasma membrane of liver stage parasites before invagination occurs. During merozoite formation, the permeability of the parasitophorous vacuole membrane changes considerably before it finally becomes completely disrupted, releasing merozoites into the host cell cytoplasm.
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BACKGROUND INFORMATION The Plasmodium parasite, during its life cycle, undergoes three phases of asexual reproduction, these being repeated rounds of erythrocytic schizogony, sporogony within oocysts on the mosquito midgut wall and exo-erythrocytic schizogony within the hepatocyte. During each phase of asexual reproduction, the parasite must ensure that every new daughter cell contains an apicoplast, as this organelle cannot be formed de novo and is essential for parasite survival. To date, studies visualizing the apicoplast in live Plasmodium parasites have been restricted to the blood stages of Plasmodium falciparum. RESULTS In the present study, we have generated Plasmodium berghei parasites in which GFP (green fluorescent protein) is targeted to the apicoplast using the specific targeting sequence of ACP (acyl carrier protein), which has allowed us to visualize this organelle in live Plasmodium parasites. During each phase of asexual reproduction, the apicoplast becomes highly branched, but remains as a single organelle until the completion of nuclear division, whereupon it divides and is rapidly segregated into newly forming daughter cells. We have shown that the antimicrobial agents azithromycin, clindamycin and doxycycline block development of the apicoplast during exo-erythrocytic schizogony in vitro, leading to impaired parasite maturation. CONCLUSIONS Using a range of powerful live microscopy techniques, we show for the first time the development of a Plasmodium organelle through the entire life cycle of the parasite. Evidence is provided that interference with the development of the Plasmodium apicoplast results in the failure to produce red-blood-cell-infective merozoites.
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Fluorescent proteins have proven to be important tools for in vitro live imaging of parasites and for imaging of parasites within the living host by intravital microscopy. We observed that a red fluorescent transgenic malaria parasite of rodents, Plasmodium berghei-RedStar, is suitable for in vitro live imaging experiments but bleaches rapidly upon illumination in intravital imaging experiments using mice. We have therefore generated two additional transgenic parasite lines expressing the novel red fluorescent proteins tdTomato and mCherry, which have been reported to be much more photostable than first- and second-generation red fluorescent proteins including RedStar. We have compared all three red fluorescent parasite lines for their use in in vitro live and intravital imaging of P. berghei blood and liver parasite stages, using both confocal and wide-field microscopy. While tdTomato bleached almost as rapidly as RedStar, mCherry showed improved photostability and was bright in all experiments performed.
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Depending on their developmental stage in the life cycle, malaria parasites develop within or outside host cells, and in extremely diverse contexts such as the vertebrate liver and blood circulation, or the insect midgut and hemocoel. Cellular and molecular mechanisms enabling the parasite to sense and respond to the intra- and the extra-cellular environments are therefore key elements for the proliferation and transmission of Plasmodium, and therefore are, from a public health perspective, strategic targets in the fight against this deadly disease. The MALSIG consortium, which was initiated in February 2009, was designed with the primary objective to integrate research ongoing in Europe and India on i) the properties of Plasmodium signalling molecules, and ii) developmental processes occurring at various points of the parasite life cycle. On one hand, functional studies of individual genes and their products in Plasmodium falciparum (and in the technically more manageable rodent model Plasmodium berghei) are providing information on parasite protein kinases and phosphatases, and of the molecules governing cyclic nucleotide metabolism and calcium signalling. On the other hand, cellular and molecular studies are elucidating key steps of parasite development such as merozoite invasion and egress in blood and liver parasite stages, control of DNA replication in asexual and sexual development, membrane dynamics and trafficking, production of gametocytes in the vertebrate host and further parasite development in the mosquito. This article, which synthetically reviews such signalling molecules and cellular processes, aims to provide a glimpse of the global frame in which the activities of the MALSIG consortium will develop over the next three years.