检索结果-南通市图书馆

Bone alterations in inflammatory bowel diseases

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2019年第15期7卷 1908-1925页

作者： Dolores Sgambato Francesca Gimigliano Cristiana De Musis Antimo Moretti Giuseppe Toro Emanuele Ferrante Agnese Miranda Domenico De Mauro lorenzo romano Giovanni Iolascon Marco romano Departments of Precision Medicine and Polyspecialistic Internal Medicine University of Campania "Luigi Vanvitelli" and University HospitalNaples 80131Italy Department of Physical and Mental Health University of Campania“Luigi Vanvitelli”Naples 80131Italy Department of Medical and Surgical Specialties and Dentistry University of Campania“Luigi Vanvitelli”Naples 80131Italy Surgical Digestive Endoscopy Department of Clinical Medicine and SurgeryFederico Ⅱ UniversityNaples 80131Italy

Inflammatory bowel diseases(IBDs)are characterized by a multifactorial partially unknown etiology that involves genetic,immunological and environmental *** to 50%of IBD patients experience at least one extraintestinal manifestation;among them is the involvement of bone density which is referred to as metabolic bone disease(MBD),including osteopenia and *** alterations in IBDs population appear to have a multifactorial etiology:Decreased physical activity,inflammation-related bone resorption,multiple intestinal resections,dietary malabsorption of minerals and vitamin D deficiency,genetic factors,gut-bone immune signaling interaction,steroid treatment,microbiota and pathogenic micro-organisms interaction,and dietary malabsorption of minerals,that,all together or individually,may contribute to the alteration of bone mineral *** review aims to summarize the prevalence and pathophysiology of metabolic bone alterations in IBD subjects outlining the main risk factors of bone *** also want to underline the role of the screening and prophylaxis of bone alterations in Crohn’s disease and ulcerative colitis patients and the importance of treating appropriately MBD.

关键词： Inflammatory bowel diseases Bone alterations Bone mineral density Osteoporosis Osteopenia Ulcerative colitis Crohn’s disease

Liver failure in an obese middle-aged woman after biliointestinal bypass

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2013年第1期1卷 52-55页

作者： Dolores Sgambato Gaetano Cotticelli Ilario de Sio Annalisa Funaro Anna Del Prete Chiara de Sio lorenzo romano Alessandro Federico Antonietta Gravina Agnese Miranda Carmelina Loguercio Marco romano Department of Clinical and Experimental Medicine "Magrassi-Lanzara" Gastroenterology Unit Second University of Naples 80131 Naples Italy

Obesity is considered an emerging epidemic that is often associated with non-alcoholic fatty liver disease. Among the therapeutic options for morbid obesity, bariatric surgery plays an important role when conventional therapies fail. The effects of bariatric surgery on liver function and morphology are controversial in the literature. Liver failure has been reported after jejunoileal bypass(JIB), biliopancreatic diversion and gastric bypass. Biliointestinal bypass(BIB) is considered an effective procedure among recently introduced bariatric surgery techniques. It is a clinically safe, purely malabsorptive operation in which the blind intestinal loop of the JIB is anastomosed to the gallbladder, allowing a portion of bile to transit into excluded intestinal tract. BIB is the only procedure, to our knowledge, to have no liver side effects reported in the literature. We report the case of a young obese woman who developed liver failure 8 mo after BIB. She had a rapid weight loss(70 kg) with a reduction in body mass index of 41% from January to September 2012. Because of a severe hepatic decompensation, she was referred to a transplantation centre. We strongly believe that the most important pathogenetic mechanism involved in the development of liver injury is the rapid weight loss that produced a signif icant fatty liver inf iltration.

关键词： Bariatric surgery Biliointestinal bypass Liver failure Non-alcoholic fatty liver disease Obesity Rapid weight loss

Predicting lower limb periprosthetic joint infections: A review of risk factors and their classification

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Orthopedics 2017年第5期8卷 400-411页

作者： David A George lorenzo Drago Sara Scarponi Enrico Gallazzi Fares S Haddad Carlo L romano Department of Trauma and Orthopaedics University College London Hospitals Microbiological Laboratory Orthopaedic Re-search Institute Galeazzi Centre for Reconstructive Surgery and Osteoarticular Infections Orthopaedic Research Institute Galeazzi

AIM To undertook a systematic review to determine factors that increase a patient's risk of developing lower limb periprosthetic joint infections(PJI).METHODS This systematic review included full-text studies that reviewed risk factors of developing either a hip or knee PJI following a primary arthroplasty published from January 1998 to November 2016. A variety of keywords were used to identify studies through international databases referencing hip arthroplasty, knee arthroplasty, infection, and risk factors. Studies were only included if they included greater than 20 patients in their study cohort, and there was clear documentation of the statistical parameter used; specifically P-value, hazard ratio, relative risk, or/and odds ratio(OR). Furthermore a quality assessment criteria for the individual studies was undertaken to evaluate the presence of record and reporting bias. RESULTS Twenty-seven original studies reviewing risk factors relating to primary total hip and knee arthroplasty infections were included. Four studies(14.8%) reviewed PJI of the hip, 3(11.21%) of the knee, and 20(74.1%) reviewed both joints. Nineteen studies(70.4%) were retrospective and 8(29.6%) prospective. Record bias was identified in the majority of studies(66.7%). The definition of PJI varied amongst the studies but there was a general consensus to define infection by previously validated methods. The most significant risks were the use of preoperative high dose steroids(OR = 21.0, 95%CI: 3.5-127.2, P < 0.001), a BMI above 50(OR = 18.3, P < 0.001), tobacco use(OR = 12.76, 95%CI: 2.47-66.16, P= 0.017), body mass index below 20(OR = 6.00, 95%CI: 1.2-30.9, P = 0.033), diabetes(OR = 5.47, 95%CI: 1.77-16.97, P = 0.003), and coronary artery disease(OR = 5.10, 95%CI: 1.3-19.8, P = 0.017).CONCLUSION We have highlighted the need for the provider to optimise modifiable risk factors, and develop strategies to limit the impact of non-modifiable factors.

关键词： Periprosthetic joint infection Risk factor Predictive Hip arthroplasty Knee arthroplasty

Colorectal cancer: Parametric evaluation of morphological,functional and molecular tomographic imaging

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2019年第35期25卷 5233-5256页

作者： Pier Paolo Mainenti Arnaldo Stanzione Salvatore Guarino Valeria Romeo lorenzo Ugga Federica romano Giovanni Storto Simone Maurea Arturo Brunetti Institute of Biostructures and Bioimaging of the National Council of Research (CNR) Naples 80145 Italy University of Naples "Federico II" Department of Advanced Biomedical Sciences Naples 80131 Italy IRCCS-CROB Referral Cancer Center of Basilicata Rionero in Vulture 85028 Italy

Colorectal cancer (CRC) represents one of the leading causes of tumor-related deaths worldwide. Among the various tools at physicians’ disposal for the diagnostic management of the disease, tomographic imaging (e.g., CT, MRI, and hybrid PET imaging) is considered essential. The qualitative and subjective evaluation of tomographic images is the main approach used to obtain valuable clinical information, although this strategy suffers from both intrinsic and operator-dependent limitations. More recently, advanced imaging techniques have been developed with the aim of overcoming these issues. Such techniques, such as diffusion-weighted MRI and perfusion imaging, were designed for the “in vivo” evaluation of specific biological tissue features in order to describe them in terms of quantitative parameters, which could answer questions difficult to address with conventional imaging alone (e.g., questions related to tissue characterization and prognosis). Furthermore, it has been observed that a large amount of numerical and statistical information is buried inside tomographic images, resulting in their invisibility during conventional assessment. This information can be extracted and represented in terms of quantitative parameters through different processes (e.g., texture analysis). Numerous researchers have focused their work on the significance of these quantitative imaging parameters for the management of CRC patients. In this review, we aimed to focus on evidence reported in the academic literature regarding the application of parametric imaging to the diagnosis, staging and prognosis of CRC while discussing future perspectives and present limitations. While the transition from purely anatomical to quantitative tomographic imaging appears achievable for CRC diagnostics, some essential milestones, such as scanning and analysis standardization and the definition of robust cut-off values, must be achieved before quantitative tomographic imaging can be incorporated into

关键词： Colorectal cancer Computed tomography Magnetic resonance imaging Positron emission tomography Parametric imaging Perfusion imaging Diffusion imaging Texture analysis

Efficacy of a therapeutic strategy for eradication of Helicobacter pylori infection

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2012年第33期18卷 4542-4548页

作者： Giuliana Sereni Francesco Azzolini lorenzo Camellini Debora Formisano Francesco Decembrino Veronica Iori Cristiana Tioli Maurizio Cavina Francesco Di Mario Giuliano Bedogni romano Sassatelli Unit of Gastroenterology and Digestive Endoscopy Arcispedale Santa Maria Nuova Istituto di Ricovero e Cura a Carattere Scientifico 42123 Reggio Emilia Italy Statistics and Clinical Epidemiology Unit Arcispedale Santa Maria Nuova Istituto di Ricovero e Cura a Carattere Scientifico 42123 Reggio Emilia Italy Unit of Gastroenterology Ospedale S. Maria di Ca' Foncello 31100 Treviso Italy

AIM: To determine the efficacy of our therapeutic strategy for Helicobacter pylori (H. pylori) eradication and to identify predictive factors for successful eradication. METHODS: From April 2006 to June 2010, we retrospectively assessed 2428 consecutive patients (1025 men, 1403 women; mean age 55 years, age range 18-92 years) with gastric histology positive for H. pylori infection referred to our unit for 13-C urea breath test(UBT), after first-line therapy with proton pump inhibitor (PPI) b.i.d. + amoxicillin 1 g b.i.d. + clarithromycin 500 mg b.i.d. for 7 d. Patients who were still positive to UBT were recommended a second-line therapy (PPI b.i.d. + amoxicillin 1 g b.i.d. + tinidazole 500 mg b.i.d. for 14 d). Third choice treatment was empirical with PPI b.i.d. + amoxicillin 1 g b.i.d. + levofloxacin 250 mg b.i.d. for 14 d. RESULTS: Out of 614 patients, still H. pylori-positive after first-line therapy, only 326 and 19 patients respectively rechecked their H. pylori status by UBT after the suggested second and third-line regimens. "Per protocol" eradication rates for first, second and thirdline therapy were 74.7% (95% CI: 72.7%-76.4%), 85.3% (95% CI: 81.1%-89.1%) and 89.5% (95% CI: 74.9%-103%) respectively. The overall percentage of patients with H. pylori eradicated after two treatments was 97.8% (95% CI: 97.1%-98.4%), vs 99.9% (95% CI: 99.8%-100%) after three treatments. The study found that eradication therapy was most effective in patients with ulcer disease (P < 0.05, P = 0.028), especially in those with duodenal ulcer. Smoking habits did not significantly affect the eradication rate. CONCLUSION: First-line therapy with amoxicillin and clarithromycin produces an H. pylori eradication rate comparable or superior to other studies and secondline treatment can still be triple therapy with amoxicillin and tinidazole.

关键词： Helicobacter pylori Eradication treatment Rescue therapy Eradication rate Triple therapy Firstline therapy Second-line therapy

Non-invasive diagnostic imaging of colorectal liver metastases

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Radiology 2015年第7期7卷 157-169页

作者： Pier Paolo Mainenti Federica romano Laura Pizzuti Sabrina Segreto Giovanni Storto lorenzo Mannelli Massimo Imbriaco Luigi Camera Simone Maurea IBB CNR Advanced Biomedical Science Department Radiology Section University of Naples "Federico II" IRCCS CROB Radiology Department Memorial Sloan-Kettering Cancer Center

Colorectal cancer is one of the few malignant tumors in which synchronous or metachronous liver metastases [colorectal liver metastases(CRLMs)] may be treated with surgery. It has been demonstrated that resection of CRLMs improves the long-term prognosis. On the other hand, patients with un-resectable CRLMs may benefit from chemotherapy alone or in addition to liverdirected therapies. The choice of the most appropriate therapeutic management of CRLMs depends mostly on the diagnostic imaging. Nowadays, multiple non-invasive imaging modalities are available and those have a pivotal role in the workup of patients with CRLMs. Although extensive research has been performed with regards to the diagnostic performance of ultrasonography, computed tomography, positron emission tomography and magnetic resonance for the detection of CRLMs, the optimal imaging strategies for staging and follow up are still to be established. This largely due to the progressive technological and pharmacological advances which are constantly improving the accuracy of each imaging modality. This review describes the non-invasive imaging approaches of CRLMs reporting the technical features, the clinical indications, the advantages and the potential limitations of each modality, as well as including some information on the development of new imaging modalities, the role of new contrast media and the feasibility of using parametric image analysis as diagnostic marker of presence of CRLMs.

关键词： Advances in imaging Colorectal cancer Liver metastases

Is there a role for treatment-oriented surgery in liver metastases from gastric cancer?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Clinical Oncology 2020年第7期11卷 477-494页

作者： Fabio Uggeri lorenzo Ripamonti Enrico Pinotti Mauro Alessandro Scotti Simone Famularo Mattia Garancini Luca Gianotti Marco Braga Fabrizio romano School of Medicine and Surgery University of Milano-BicoccaDepartment of SurgerySan Gerardo HospitalMonza 20900Italy Department of Surgery San Gerardo HospitalMonza 20900Italy

BACKGROUND Distant metastases are found in approximately 35%of patients with gastric cancer at their first clinical observation,and of these,4%-14%involves the ***,only 0.4%-2.3%of patients with metastatic gastric cancer are eligible for radical *** surgical resection for gastric cancer metastases is still debated,there have been changes in recent years,although several clinical issues remain to be defined and that must be taken into account before surgery is *** To analyze the clinicopathological factors related to primary gastric tumor and metastases that impact the survival of patients with liver metastatic gastric *** We performed a systematic review of the literature from 2000 to 2018 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses *** study protocol was based on identifying studies with clearly defined purpose,eligibility criteria,methodological analysis,and patient *** We selected 47 studies pertaining to the purpose of the review,which involved a total of 2304 *** survival was 7-52.3 mo,median disease-free survival was 4.7-18 *** 1-,2-,3-,and 5-year overall survival(OS)was 33%-90.1%,10%-60%,6%-70.4%,and 0%-40.1%,*** five papers reported the 10-year OS,which was 5.5%–31.5%.The general recurrence rate was between 55.5%and 96%,and that for hepatic recurrence was between 15%and 94%.CONCLUSION Serous infiltration and lymph node involvement of the primary cancer indicate an unfavorable prognosis,while the presence of single metastasis or≤3 metastases associated with a size of<5 cm may be considered data that do not contraindicate liver resection.

关键词： Hepatic metastases Gastric cancer Prognostic factor Survival Hepatectomy Surgery

Hepatitis C virus-related B cell subtypes in non Hodgkin's lymphoma

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Hepatology 2011年第11期3卷 278-284页

作者： Adriano M Pellicelli Massimo Marignani Valerio Zoli Mario romano Aldo Morrone lorenzo Nosotti Giuseppe Barbaro Antonio Picardi Umberto Vespasiani Gentilucci Daniele Remotti Cecilia D'Ambrosio Caterina Furlan Fabrizio Mecenate Ettore Mazzoni Ignazio Majolino Roberto Villani Arnaldo Andreoli Giorgio Barbarini Liver Unit Azienda Ospedaliera San Camillo Forlanini Circonvallazione Gianicolense 8700149 Rome Italy Department of Digestive and Liver Disease Azienda Ospedaliera Sant’AndreaVia Grottarossa 1035/1039000189 Rome Italy Hematology and Bone Marrow Transplantation Azienda Ospedaliera San Camillo ForlaniniCirconvallazione Gianicolense 8700149 Rome Italy Liver Unit Ospedale Sandro PertiniVia dei Monti Tiburtini 38500157 Rome Italy Azienda Ospedaliera San Camillo Forlanini Circonvallazione Gianicolense87 00149 Rome Italy Medicine of Migration National Institute for Migrant Health and Poverty Via di S. Gallicano 25/a 00153Rome Italy Department of Medical Pathophysiology University of Rome "La Sapienza" Viale del Policlinico 15500161 Rome Italy Liver Unit Campus Biomedico UniversityVia álvaro del Portillo 21 00128Rome Italy Histopathology Unit Azienda Ospedaliera San Camillo ForlaniniCirconvallazione Gianicolense 8700149Rome Italy Liver Unit Azienda Ospedaliera San Camillo ForlaniniCirconvallazione Gianicolense 8700149 Rome Italy Department of Infectious and Tropical Disease University of Rome"La Sapienza"Viale del Policlinico155 00161 Rome Italy Liver Unit Ospedale Villa BetaniaVia Niccolò Piccolomini 2700165 RomeItaly Liver Unit Policlinico CasilinoVia Casilina104900169 Rome Italy Hematology and Bone Marrow Transplantation Azienda Ospedaliera San Camillo ForlaniniCirconvallazione Gianicolense 8700149 RomeItaly Liver Unit Azienda Ospedaliera San Camillo ForlaniniCirconvallazione Gianicolense 8700149 RomeItaly Infectious and Parasitic Diseases Policlinico San Matteo P.zzale Golgi 2 2710 PaviaItaly

AIM:To evaluate if indolent B cell-non Hodgkin's lymphoma(B-NHL) and diffuse large B-cell lymphoma(DLBCL) in hepatitis C virus(HCV) positive patients could have different biological and clinical characteristics requiring different management ***:A group of 24 HCV related B-NHL patients(11 indolent,13 DLBCL) in whom the biological and clinical characteristics were described and *** with DLBCL were managed with the standard of care of *** with indolent HCV-related B-NHL were managed with antiviral treatment pegylated interferon plus ribavirin and their course *** outcomes of the different approaches were ***:Patients with DLBCL had a shorter duration of HCV infection and a higher prevalence of HCV genotype 1 compared to patients with indolent B-NHL in which HCV genotype 2 was the more frequent *** of the 9 patients with indolent HCV-relatedB-NHL treated with only antiviral therapy,achieved a complete response of their onco-haematological disease(55%).Seven of the 13 DLBCL patients treated with immunochemotheraphy obtained a complete response(54%).CONCLUSION:HCV genotypes and duration of HCV infection differed between B-NHL *** lymphomas can be managed with antiviral treatment,while DLBCL is not affected by the HCV infection.

关键词： Hepatitis C virus infection Diffuse large B cell lymphoma Indolent lymphoma Pegylated interferon Lymphomagenesis

Boceprevir or telaprevir in hepatitis C virus chronic infection:The Italian real life experience

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Hepatology 2016年第22期8卷 949-956页

作者： Antonio Ascione Luigi Elio Adinolfi Pietro Amoroso Angelo Andriulli Orlando Armignacco Tiziana Ascione Sergio Babudieri Giorgio Barbarini Michele Brogna Francesco Cesario Vincenzo Citro Ernesto Claar Raffaele Cozzolongo Giuseppe D’Adamo Emilio D’Amico Pellegrino Dattolo Massimo De Luca Vincenzo De Maria Massimo De Siena Giuseppe De Vita Antonio Di Giacomo Rosanna De Marco Giorgio De Stefano Giulio De Stefano Sebastiano Di Salvo Raffaele Di Sarno Nunzia Farella Laura Felicioni Basilio Fimiani Luca Fontanella Giuseppe Foti Caterina Furlan Francesca Giancotti Giancarlo Giolitto Tiziana Gravina Barbara Guerrera Roberto Gulminetti Angelo Iacobellis Michele Imparato Angelo Iodice Vincenzo Iovinella Antonio Izzi Alfonso Liberti Pietro Leo Gennaro Lettieri Ileana Luppino Aldo Marrone Ettore Mazzoni Vincenzo Messina Roberto Monarca Vincenzo Narciso lorenzo Nosotti Adriano Maria Pellicelli Alessandro Perrella Guido Piai Antonio Picardi Paola Pierri Grazia Pietromatera Francesco Resta Luca Rinaldi Mario romano Angelo Rossini Maurizio Russello Grazia Russo Rodolfo Sacco Vincenzo Sangiovanni Antonio Schiano Antonio Sciambra Gaetano Scifo Filomena Simeone Annarita Sullo Pierluigi Tarquini Paolo Tundo Alfredo Vallone Depart-ment of Medicine Center for Liver Diseases "Buon Consiglio" -Fatebenefratelli Hospital Internal Medicine Unit Second University of Naples VI Division of Infectious Diseases Cotugno Hospital AORN "Ospedali dei Colli" Division of Gastro- enterology Casa Sollievo Sofferenza Hospital IRCCS Division of Infectious Diseases Belcolle Hospital IX Division of Infectious Diseases Cotugno Hospital AORN "Ospedali dei Colli" Clinical of Infectious Disease University of Sassari Infectious Disease IRCCS San Matteo Division of Infectious Diseases and Liver Unit "G. Iazzolino" Hospital Division of Infectious Diseases "Annunziata" Hospital Depart-ment of Internal Medicine Umberto I Hospital Internal Medicine Ospedale Evangelico Villa Betania Division of Gastroenterology IRCCS "S.de Bellis" Hospital Internal Medicine Unit Pescara-Penne Hospital Gastroenterology Unit Marcianise Hospital Liver Unit AORN Cardarelli Liver Unit Policlinico "Mater Domini" Service of Medical Day Hospital "Rummo" Hospital Internal Medicine Regina Margherita Hospital Division of Gastroenterology "Annunziata" Hospital Infectious Disease Matera Hospital First Division of Infectious Diseases Cotugno Hospital AORN "Ospedali dei Colli" Division of Infectious Diseases AO Melacrino- Bianchi-Morelli Infectious and Tropical Disease Policlinico Umberto I Division of Infectious Disease Maria SS Addolorata Hospital Division of Infectious Diseases S. Anna and S. Sebastiano Hospital Outpatients Service for Liver Diseases "Loreto Crispi" Hospital V Division of Infectious Diseases Cotugno Hospital AORN "Ospedali dei Colli" Department of Medical Surgical Neurological Geriatric and Metabolic Sciences Second Univer-sity of Naples Liver Unit Policlinico Casilino Medicine and Health Unit for Prisoners Belcolle Hospital Internal Medicine Unit "Ascalesi" Hospital Gastrointestinal and Liver Department National Institute for Health Migration and Poverty Liver Unit Azienda Ospedaliera San Camillo Forlanini VII Division of Infectious Diseases

AIM: To check the safety and efficacy of boceprevir/telaprevir with peginterferon/ribavirin for hepatitis C virus(HCV) genotype 1 in the real-world settings. METHODS: This study was a non-randomized, observational, prospective, multicenter. This study involved 47 centers in Italy. A database was prepared for the homogenous collection of the data, was used by all of the centers for data collection, and was updated continuously. All of the patients enrolled in this study were older than 18 years of age and were diagnosed with chronic infection due to HCV genotype 1. The HCV RNA testing was performed using COBAS-Taq Man2.0(Roche, LLQ 25 IU/m L). RESULTS: All consecutively treated patients were included. Forty-seven centers enrolled 834 patients as follows: Male 64%; median age 57(range 18-78), of whom 18.3% were over 65; mean body mass index 25.6(range 16-39); genotype 1b(79.4%); diagnosis of cirrhosis(38.2%); and fibrosis F3/4(71.2%). The following drugs were used: Telaprevir(66.2%) and PEG-IFN-alpha2a(67.6%). Patients were na?ve(24.4%), relapsers(30.5%), partial responders(14.8%) and null responders(30.3%). Overall, adverse events(AEs) occurred in 617 patients(73.9%) during the treatment. Anemia was the most frequent AE(52.9% of cases), especially in cirrhotic. The therapy was stopped for 14.6% of the patients because of adverse events or virological failure(15%). Sustained virological response was achieved in 62.7% of the cases, but was 43.8% in cirrhotic patients over 65 years of age. CONCLUSION: In everyday practice, triple therapy is safe but has moderate efficacy, especially for patients over 65 years of age, with advanced fibrosis, nonresponders to peginterferon + ribavirin.

关键词： Boceprevir Telaprevir Chronic hepatitis Antiviral therapy Peg-interferon Ribavirin