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Dive into the research topics where Bernardo Frider is active.

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Featured researches published by Bernardo Frider.


Journal of Hepatology | 1999

Long-term outcome of asymptomatic liver hydatidosis

Bernardo Frider; Edmundo Larrieu; Martín Odriozola

BACKGROUND/AIMS The aim of this study was to determine the outcome of asymptomatic liver hydatid cysts in a cohort of 33 out of 59 carriers by evaluating clinical and ultrasonographic (US) changes 10-12 years after initial diagnosis. METHODS We compared US features and cyst size with the original descriptions from 1984-1986. Patients were questioned about hydatid-related symptoms and signs. RESULTS Thirty-three of the 59 carriers could be reevaluated, five (15.2%) of whom had undergone surgery without presenting symptoms, while of 28 unoperated cases, 21 (75%) remained asymptomatic. Of the unoperated cases evaluated by US, in 8/14 (57.1%) there were no modifications in cyst size during the 10-12-year period, in five (35.7%) growth was slight (<3 cm) and in one (7.1%) the cyst grew 4 cm. Mean cyst growth in all 14 cases was 0.7 cm. CONCLUSIONS Despite the limited number of cases, our results show that most asymptomatic liver hydatid cases (75%) remain symptom-free for more than 10 years, regardless of cyst size or type. We believe that such carriers are at low risk of developing complications, so that it is difficult to establish specific rules for their therapy, if any. Longitudinal follow-up of larger series of asymptomatic hepatic hydatidosis cases is essential to gain a deeper insight into the natural history of such patients, and to draw up comprehensive guidelines for treatment.


Acta Tropica | 2001

Epidemiological surveillance of human hydatidosis by means of ultrasonography: its contribution to the evaluation of control programs

Bernardo Frider; Jorge Moguilensky; Juan Carlos Salvitti; Martín Odriozola; Gustavo Cantoni; Edmundo Larrieu

Epidemiological surveillance for hydatidosis is based on initial determination and follow-up of the infestation rate in man, sheep and dogs. The use of ultrasonography (US) as a screening method has demonstrated its usefulness in detecting asymptomatic human carriers of abdominal hydatidosis. To evaluate the contribution of US to epidemiological surveillance within the framework of disease control programs, we performed 719 US studies in school children from 7 to 13 years of age, in rural areas of Río Negro, Argentina, subjected to canine deparasitization during 1984/1986 and 1997/1998. In the first period, 15/268 (5.6%), while in the second, 5/451 (1.1%) carriers were detected (P < 0.0004). The average diameter of the cysts was 4.71 cm in 1984/1986 and 2.14 in 1997/1998. US as a mass screening method allows evaluation of early changes in human prevalence rates, closely related to infestation rates in sheeps and dogs, thus providing a sensitive indicator of the evaluation of control programs.


Revista Panamericana De Salud Publica-pan American Journal of Public Health | 2000

Portadores asintomaticos de hidatidosis: epidemiologia, diagnostico y tratamiento

Edmundo Larrieu; Bernardo Frider; Mario Del Carpio; Juan Carlos Salvitti; Carlos Mercapide; Rubén A Pereyra; Maria da Conceição Nascimento Costa; Martín Odriozola; Alicia Perez; Gustavo Cantoni; José Sustercic

Until a short time ago, hydatidosis was considered a pathology that could only be resolved surgically. However, in recent years progress has been made with the epidemiology, diagnosis, and treatment of the disease, and new information on the natural history of hydatidosis has helped define new criteria for its treatment. It is now known that as many as 67% of the carriers of liver cysts who are asymptomatic remain so throughout their lives. This situation produces special results in immunologic testing. Enzyme-linked immunosorbent assay (ELISA) has a sensitivity of 63% and a specificity of 97% with asymptomatic carriers, while the double diffusion arc 5 test (DD5) achieves a sensitivity of only 31% with the same population. On the other hand, imaging studies based on ultrasonography have become the method of choice to detect asymptomatic carriers. Ultrasonography studies are 49% to 73% more sensitive than serological tests, and they can even be used as a part of epidemiological surveillance systems and to monitor control programs. Treatment schemes have also been modernized. Treating asymptomatic carriers chemotherapeutically with albendazole produces favorable results in as many as 69% of cases, while such minimally invasive surgical treatments as puncture-aspiration-injection-reaspiration (PAIR) reduce average cyst volume by as much as 66%. These factors have made it possible for hospital services in the province of Río Negro, Argentina, to establish a treatment scheme for asymptomatic carriers. It is based on the monitoring of small cysts (type Ia on the modified Gharbi scale); initial treatment with albendazole, followed by PAIR if there is no response, in larger or more complex cysts (types Ib, II, and III); and follow-up of inviable or dead cysts (types IV and V).


International Journal of Dermatology | 1996

HEPATITIS C VIRUS ANTIBODY (ANTI‐HCV): PREVALENCE IN PSORIASIS

Edgardo Chouela; Alejandra Abeldaño; Josefina Panetta; Mariana Ducard; Vincenta Negeia; Silvia Sookoian; Mirta Kina; Gustavo Castaño; Fernando Vereytou; Bernardo Frider

Background. In cases of psoriasis (PS), the etiology of the underlying liver disease is occasionally unknown. To investigate antibodies to hepatitis C virus (anti‐HCV), their prevalence and clinical significance, 118 unselected outpatients with PS were studied prospectively.


Journal of Cutaneous Medicine and Surgery | 2001

Development of cutaneous sarcoidosis in a patient with chronic hepatitis C treated with interferon alpha 2b

Neglia; Silvia Sookoian; Herrera M; Alejandra Abeldaño; Kien Mc; Edgardo Chouela; Bernardo Frider

Background: Sarcoidosis is a multisystemic granulomatous disorder of unknown etiology that most commonly affects young adults. A probable induction of sarcoidosis by interferons (IFN) has been published. To this date, few cases of cutaneous sarcoidosis in patients with chronic hepatitis C under interferon treatment have been reported. Objective: We describe a 50-year-old woman with chronic hepatitis C who developed lesions of cutaneous sarcoidosis three months after IFN treatment. Conclusions: The possible role of INF therapy in the development of cutaneous sarcoidosis in a patient with chronic hepatitis C should be considered.


Journal of Clinical Microbiology | 2006

Unusual Naturally Occurring Humoral and Cellular Mutated Epitopes of Hepatitis B Virus in a Chronically Infected Argentine Patient with Anti-HBs Antibodies

María L. Cuestas; Verónica L. Mathet; Vanesa Ruiz; María L. Minassian; Cintia Rivero; Andrea Sala; Daniel Corach; Analía Alessio; Marcia Pozzati; Bernardo Frider; José R. Oubiña

ABSTRACT Serum hepatitis B virus (HBV) DNA was extracted from a chronically infected patient with cocirculation of hepatitis B surface antigen (HBsAg) and anti-HBs antibodies. Direct PCR and clone-derived sequences of the S and overlapped P genes were obtained. DNA sequences and phylogenetic analysis ascribed this isolate to genotype A (serotype adw2). Five of six HBV DNA clones exhibited point mutations inside and outside the major hydrophilic region, while the sixth clone exhibited a genotype A “wild-type” amino acid sequence. Observed replacements included both humoral and/or cellular (major histocompatibility complex class I [MHC-I] and MHC-II) HBV mutated epitopes, such as S45A, P46H, L49H, C107R, T125A, M133K, I152F, P153T, T161S, G185E, A194T, G202R, and I213L. None of these mutants were individually present within a given clone. The I213L replacement was the only one observed in the five clones carrying nonsynonymous mutations in the S gene. Some of the amino acid substitutions are reportedly known to be responsible for the emergence of immune escape mutants. C107R replacement prevents disulfide bonding, thus disrupting the first loop of the HBsAg. Circulation of some of these mutants may represent a potential risk for the community, since neither current hepatitis B vaccines nor hyperimmune hepatitis B immune globulin are effectively prevent the liver disease thereto associated. Moreover, some of the recorded HBsAg variants may influence the accuracy of the results obtained with currently used diagnostic tests.


Liver International | 2016

Cyproterone acetate induces a wide spectrum of acute liver damage including corticosteroid-responsive hepatitis: report of 22 cases

Fernando Bessone; M.I. Lucena; Marcelo G. Roma; Camilla Stephens; I. Medina-Cáliz; Bernardo Frider; Guillermo Tsariktsian; Nelia Hernández; Miquel Bruguera; Gisela Gualano; Eduardo Fassio; Joaquín Montero; Maria V. Reggiardo; Sebastián Ferretti; Luis Colombato; Federico Tanno; Jaime Ferrer; Lelio Zeno; Hugo Tanno; Raúl J. Andrade

Cyproterone acetate (CPA), an anti‐androgenic drug for prostate cancer, has been associated with drug‐induced liver injury (DILI). We aim to expand the knowledge on the spectrum of phenotypes and outcomes of CPA‐induced DILI.


Antiviral Research | 2010

Naturally occurring hepatitis B virus (HBV) variants with primary resistance to antiviral therapy and S-mutants with potential primary resistance to adefovir in Argentina.

María L. Cuestas; Cintia Rivero; María L. Minassian; Emiliano Alberto Gentile; Julieta Trinks; Liliana León; Graciela Daleoso; Bernardo Frider; Carol Lezama; Marcela Galoppo; Gisela Giacove; Verónica L. Mathet; José R. Oubiña

Hepatitis B virus (HBV) variants may either emerge in patients with chronic hepatitis B (CHB) as a result of positive selection pressure exerted by their own immune response, or during therapy with nucleos(t)ide analogues (NAs). Naturally occurring HBV variants with primary antiviral resistance are rarely observed. The aim of this study was to retrospectively analyze the (eventual) circulation of HBV variants with natural resistance to NAs currently used as therapy for CHB in Argentina. This study reports 13 cases of CHB-infected patients with natural antiviral resistance to at least one NA. Five of them were also carriers of S-variants that might escape the humoral immune system recognition with potential resistance to adefovir. In addition to the already reported A2 HBV subgenotype association to NAs natural resistance, E and F genotypes association to such resistance is described for the first time. These findings suggest that sequence analysis of the HBV reverse transcriptase might be an essential tool before starting antiviral therapy, in order to choose the proper NAs for optimizing the therapeutic management of chronically infected patients. Moreover, the circulation and transmission of S-mutants with resistance to such antiviral drugs should be of public health concern as they may represent an additional risk for the community.


Digestive Diseases and Sciences | 2001

Combined Therapy with Interferon and Ribavirin in Chronic Hepatitis C Does Not Affect Serum Quasispecies Diversity

Silvia Sookoian; Gustavo Castaño; Bernardo Frider; Jerónimo Cello; Rodolfo Campos; Diego Flichman

Our aim was to investigate if interferon plus ribavirin has any effect on serum HCV quasispecies distribution and the relationship between diversity of HCV quasispecies and treatment response. In all, 21 patients were treated with interferon plus ribavirin for 48 weeks. The presence of HCV quasispecies was determined in serum samples at baseline and at the fourth week of treatment by SSCP analysis of the hypervariable region. SSCP pattern was defined as single or multiple band. A single band was found in six patients and multiple bands in nine. No significant difference was found between SSCP pattern in pretreatment samples and response to the therapy. In none of the patients were observed changes in number of SSCP bands between samples taken at baseline and in the fourth week of the therapy. In conclusion, the complexity of HCV quasispecies before the therapy was not related to treatment response; combined therapy did not affect serum HCV quasispecies.


Revista Do Instituto De Medicina Tropical De Sao Paulo | 1989

Hidatidosis humana: ecografía de campo para la determinación de grupos de alto riesgo en la evaluación de un programa de control

Edmundo Larrieu; Bernardo Frider; Gustavo Andreani; Georgina Andreani; Alberto Aquino; Reinaldo de la Fuente

The development of small ultrasonographic equipment has permitted to incorporate this technique to the methods of early detection of Human Hydatidosis. 689 ecographies were carried out in this experience, and 5.51% of compatible images in the whole population, and 12.24% in groups of risk (those living together with the operated ones) were found. It was observed a significant decrease in the infection percentages in man in the whole population of areas under Control Program, using the ecographic screening. In conclusion, ecography might be incorporated to the epidemiologic surveillance system of human Hydatidosis.The development of small ultrasonographic equipment has permitted to incorporate this technique to the methods of early detection of Human Hydatidosis. 689 echographies were carried out in this experience, and 5.51% of compatible images in the whole population, and 12.24% in groups of risk (those living together with the operated ones) were found. It was observed a significant decrease in the infection percentages in man in the whole population of areas under Control Program, using the echographic screening. In conclusion, echography might be incorporated to the epidemiologic surveillance system of human Hydatidosis.

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Gustavo Castaño

University of Buenos Aires

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Edmundo Larrieu

National University of La Pampa

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José R. Oubiña

University of Buenos Aires

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Analía Alessio

University of Buenos Aires

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Diego Flichman

University of Buenos Aires

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