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1.
Chembiochem ; : e202400640, 2024 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-39383297

RESUMO

Multidrug Resistance (MDR) can be considered one of the most frightening adaptation types in bacteria, fungi, protozoa, and eukaryotic cells. It allows the organisms to survive the attack of many drugs used in the daily basis. This force the development of new and more complex, highly specific drugs to fight diseases. Given the high usage of medicaments, poor variation in active chemical cores, and self-medication, the appearance of MDR is more frequent each time, and has been established as a serious medical and social problem. Over the years it has been possible the identification of several genes and proteins responsible for MDR and with that the development of blockers of them to reach MDR reversion and try to avoid a global problem. These mechanisms also have been observed in cancer cells, and several calcium channel blockers have been successful in MDR reversion, and the maleimide can be found included in them. In this review we explore the history, mechanisms, reversion efforts, and we specifically focused on the maleimide synthesis as MDR-reversers in co-administration, as well as their biological applications in a urge to expand the available information and explore a very plausible MDR reversion source.

2.
Microbiol Spectr ; 12(10): e0117324, 2024 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-39190636

RESUMO

Klebsiella pneumoniae strains that produce Klebsiella pneumoniae Carbapenemase (KPC) variants displaying resistance to ceftazidime-avibactam (CZA) often remain susceptible to meropenem (MEM), suggesting a potential therapeutic use of this carbapenem antibiotic. However, in vitro studies indicate that these sorts of strains can mutate becoming MEM-resistant, raising concerns about the effectiveness of carbapenems as treatment option. We have studied mutation rates occurring from the reversion of MEM-susceptible KPC-114 to MEM-resistant KPC-2, in CZA-resistant K. pneumoniae belonging to ST11. Two-step fluctuation assays (FAs) were conducted. In brief, initial cultures of KPC-114-producing K. pneumoniae showing 1 µg/mL MEM MIC were spread on Mueller-Hinton agar plates containing 2-8 µg/mL MEM. A second step of FA, at 4-16 µg/mL MEM was performed from a mutant colony obtained at 2 µg/mL MEM. Mutation rates were calculated using maximum likelihood estimation. Parental and mutant strains were sequenced by Illumina NextSeq, and mutations were predicted by variant-calling analysis. At 8 µg/mL MEM, mutants derived from parental CZA-resistant (MIC ≥ 64 µg/mL)/MEM-susceptible (MIC = 1 µg/mL) KPC-114-positive K. pneumoniae exhibited an accumulative mutation rate of 3.05 × 10-19 mutations/cell/generation, whereas at 16 µg/mL MEM an accumulative mutation rate of 1.33 × 10-19 mutations/cell/generation resulted in the reversion of KPC-114 (S181_P182 deletion) to KPC-2. These findings highlight that the reversion of MEM-susceptible KPC-114 to MEM-resistant KPC-2, in CZA-resistant K. pneumoniae ST11 is related to low mutation rates suggesting a low risk of therapeutic failure. In vivo investigations are necessary to confirm the clinical potential of MEM against CZA-resistant KPC variants.IMPORTANCEThe emergence of ceftazidime-avibactam (CZA) resistance among carbapenem-resistant Klebsiella pneumoniae is a major concern due to the limited therapeutic options. Strikingly, KPC mutations mediating CZA resistance are generally associated with meropenem susceptibility, suggesting a potential therapeutic use of this carbapenem antibiotic. However, the reversion of meropenem-susceptible to meropenem-resistant could be expected. Therefore, knowing the mutation rate related to this genetic event is essential to estimate the potential use of meropenem against CZA-resistant KPC-producing K. pneumoniae. In this study, we demonstrate, in vitro, that under high concentrations of meropenem, reversion of KPC-114 to KPC-2 in CZA-resistant/meropenem-susceptible K. pneumoniae belonging to the global high-risk ST11 is related to low mutation rates.


Assuntos
Antibacterianos , Compostos Azabicíclicos , Proteínas de Bactérias , Ceftazidima , Combinação de Medicamentos , Infecções por Klebsiella , Klebsiella pneumoniae , Meropeném , Testes de Sensibilidade Microbiana , Taxa de Mutação , beta-Lactamases , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , Ceftazidima/farmacologia , Compostos Azabicíclicos/farmacologia , beta-Lactamases/genética , beta-Lactamases/metabolismo , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Meropeném/farmacologia , Humanos , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , Mutação
3.
J Med Case Rep ; 17(1): 407, 2023 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-37743480

RESUMO

BACKGROUND: The BRCA2 gene is a well-known tumor suppressor gene implicated in breast and ovarian cancers. BRCA1/2 mutations can be sensitive to poly ADP-ribose polymerase (PARP) inhibitors such as olaparib. However, some of these patients develop resistance to this treatment and an essential factor contributing to acquired insensitivity is the occurrence of reversion mutations in the BRCA1/2 genes. CASE PRESENTATION: We report the case of a 65-year-old Brazilian female patient who had previously been diagnosed with metastatic lung carcinoma carrying a BRCA2 mutation that had extended to the central nervous system. Following disease progression, olaparib was administered, resulting in a stabilizing effect on her condition for ~ 30 months. During a routine follow-up, a new triple-negative breast tumor was found. Genetic testing revealed the presence of two distinct BRCA2 gene mutations in the breast tumor. The original mutation (p.Val220Ilefs4) led to a frameshift, culminating in the production of a truncated and non-functional BRCA2 protein; the second mutation, K437fs22, rectified the reading frame of exon 11. Consequently, Rad51 could properly bind to BRCA2-an essential protein crucial for DNA repair. This restoration resulted in a functional BRCA2 protein, effectively elucidating the clinical resistance observed in the new breast tumor in this case. CONCLUSIONS: This case report highlights the clinical significance of comprehensive next-generation sequencing analyses for lung adenocarcinomas, both at diagnosis and upon progression. Such analyses enable informed decisions regarding targeted therapies and facilitate a deeper comprehension of resistance mechanisms.


Assuntos
Adenocarcinoma de Pulmão , Neoplasias Pulmonares , Neoplasias de Mama Triplo Negativas , Feminino , Humanos , Idoso , Proteína BRCA2/genética , Proteína BRCA1 , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genética , Adenocarcinoma de Pulmão/tratamento farmacológico , Adenocarcinoma de Pulmão/genética , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Mutação
4.
Phytomedicine ; 120: 155069, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37722186

RESUMO

BACKGROUND: According to the WHO, 12 bacteria cause numerous human infections, including Enterobacteriaceae Klebsiella pneumoniae, and thus represent a public health problem. Microbial resistance is associated with biofilm formation; therefore, it is critical to know the biofilm-inducing potential of various compounds of everyday life. Likewise, the reversibility of biofilms and the modulation of persister cells are important for controlling microbial pathogens. In this work, we investigated the biofilm-inducing effects of xanthones from Garcinia mangostana on Klebsiella pneumoniae. Furthermore, we investigated the reversal effect of 3-methyl-2(5H)-furanone and the formation of persister cells induced by xanthones and their role in modulating the biofilm to the antibiotic gentamicin. METHODS: To analyze the biofilm-inducing role of xanthones from Garcinia mangostana, cultures of K. pneumoniae containing duodenal probe pieces were treated with 0.1-0.001 µM α- and γ-mangostin, and the biofilm levels were measured using spectrophotometry. To determine biofilm reversion, cultures treated with xanthones, or gentamicin were mixed with 3-methyl-2(5H)-furanone or N-butyryl-DL-homoserine lactone. The presence of K. pneumoniae persister cells was determined by applying the compounds to the mature biofilm, and the number of colony-forming units was counted. RESULTS: The xanthones α- and γ-mangostin increased K. pneumoniae biofilm production by 40% with duodenal probes. However, 3-methyl-2(5H)-furanone at 0.001 µΜ reversed biofilm formation by up to 60%. Moreover, adding the same to a culture treated with gentamicin reduced the biofilm by 80.5%. This effect was highlighted when 3-methyl-2(5H)-furanone was administered 6 h later than xanthones. At high concentrations of α-mangostin, persister K. pneumoniae cells in the biofilm were about 5 - 10 times more abundant than cells, whereas, with γ-mangostin, they were about 100 times more. CONCLUSION: Two xanthones, α- and γ-mangostin from G. mangostana, induced biofilm formation in K. pneumoniae and promoted persister cells. However, the biofilm formation was reversed by adding 3-methyl-2(5H)-furanone, and even this effect was achieved with gentamicin. In addition, this compound controlled the persister K. pneumoniae cells promoted by α-mangostin. Thus, synthetic, and natural biofilm-inducing compounds could harm human health. Therefore, avoiding these substances and looking for biofilm inhibitors would be a strategy to overcome microbial resistance and recover antibiotics that are no longer used.


Assuntos
Garcinia mangostana , Xantonas , Humanos , Lactonas , Antibacterianos/farmacologia , Biofilmes , Gentamicinas , Serina , Xantonas/farmacologia
5.
Arch. latinoam. nutr ; Arch. latinoam. nutr;73(2): 122-134, jun. 2023. tab, graf
Artigo em Inglês | LILACS, LIVECS | ID: biblio-1510011

RESUMO

Non-Alcoholic Fatty Liver disease (NAFLD) can lead to Non Alcoholic steatohepatitis (NASH), cirrhosis, and liver cancer. The treatment for NAFLD involves modification of caloric intake and physical activity. NAFLD has a pro-oxidant nature; therefore, it is logical to suppose that the antioxidant methionine can be used as a treatment for this disease. Aim. This study aimed to evaluate the effect of high-methionine dietary therapy on patients with NAFLD. Materials and methods. A randomized clinical study was conducted over three months. In this study, 121 NAFLD patients participated, and the age of the participants was ≥ 20 years (experimental group included 56 and control group 65), all of whom were randomized and matched by sex, recluted from the ISSSTE hospital in Xalapa, Mexico. The patients were instructed to consume food to cover the recommended methionine daily doses, and the daily amount consumed was calculated. Methionine effect was measured as NAFLD regression and quality of life improvement. Results. Nutritional therapy induced NAFLD regression and diminished central fat accumulation, blood pressure, and the fatty liver index. Some parameters, such as liver enzymes, did not changed. The quality of life of patients improved after treatment. Conclusions. In this study, we show a hepatoprotective effect induced only in three months of chances in the diet, thus, a longer diet may generate more relevant benefits in the resistant parameters of our study(AU)


La enfermedad del hígado graso no alcohólico (NAFLD) puede conducir a la esteatohepatitis no alcohólica (NASH), la cirrosis y el cáncer de hígado. El tratamiento para NAFLD es la modificación de la ingesta calórica y la actividad física. Debido a que NAFLD tiene una naturaleza pro-oxidante; es lógico suponer que el antioxidante metionina puede utilizarse en el tratamiento de esta enfermedad. Objetivo. el presente trabajo evaluó el papel de la terapia nutricional con alimentos ricos en metioninaen pacientes con NAFLD. Materiales y Métodos. Se realizó un ensayo clínico aleatorizado durante tres meses. Participaron en el estudio 121 pacientes con NAFLD con edad ≥ 20 años (56 en el grupo experimental y 65 en el control), todos aleatorizados y pareados por sexo, reclutados de la Clínica Hospital ISSTE en la ciudad de Xalapa, México, en el año 2015. Se instruyó a los pacientes en consumir los alimentos hasta completar la dosis diaria recomendada de metioninay se calculó la cantidad diaria consumida. Su efecto se midió como la regresión de NAFLD y la mejora de la calidad de vida. Resultados. La terapia nutricional retrocedió NAFLD; disminuyó la acumulación de grasa central, la presión arterial y el índice de hígado graso. Algunos parámetros, como las enzimas de la función hepática, no se modificaron con el tratamiento. Otro parámetro fue la mejora de la calidad de vida de los pacientes tratados. Conclusiones. En este trabajo mostramos un impacto hepatoprotector producido con tan solo tres meses de cambios en la dieta, por lo que una dieta más prolongada podría generar beneficios aún más significativos en los parámetros resistentes en nuestro protocolo(AU)


Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Comportamento Alimentar , Hepatopatia Gordurosa não Alcoólica , Cirrose Hepática , Ingestão de Energia , Exercício Físico , Dieta , Metionina
6.
Cancer Drug Resist ; 5(2): 277-303, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35800371

RESUMO

Multiple drug resistance (MDR) is the tumor's way of escaping the cytotoxic effects of various unrelated chemotherapeutic drugs. It can be either innate or acquired. MDR represents the end of the therapeutic pathway, and it practically leaves no treatment alternatives. Reversing MDR is an unfulfilled goal, despite the important recent advances in cancer research. MDR, the main cause of death in cancer patients, is a multi-factorial development, and most of its known causes have been thoroughly discussed in the literature. However, there is one aspect that has not received adequate consideration - intracellular alkalosis - which is part of wider pH deregulation where the pH gradient is inverted, meaning that extracellular pH is decreased and intracellular pH increased. This situation interacts with MDR and with the proteins involved, such as P-gp, breast cancer resistance protein, and multidrug associated resistance protein 1. However, there are also situations in which these proteins play no role at all, and where pH takes the lead. This is the case in ion trapping. Reversing the pH gradient to normal can be an important contribution to managing MDR. The drugs to manipulate pH exist, and most of them are FDA approved and in clinical use for other purposes. Furthermore, they have low or no toxicity and are inexpensive compared with any chemotherapeutic treatment. Repurposing these drugs and combining them in a reasonable fashion is one of the points proposed in this paper, which discusses the relationship between cancer's peculiar pH and MDR.

7.
J Pediatr ; 245: 149-157.e1, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35120982

RESUMO

OBJECTIVE: To assess outcomes from the US postarrival evaluation of newly arrived immigrant and refugee children aged 2-14 years who were diagnosed with latent tuberculosis infection (LTBI) during a required overseas medical examination. STUDY DESIGN: We compared overseas and US interferon-γ release assay (IGRA)/tuberculin skin test (TST) results and LTBI diagnosis; assessed postarrival LTBI treatment initiation and completion; and evaluated the impact of switching from TST to IGRA to detect Mycobacterium tuberculosis infection overseas. RESULTS: In total, 73 014 children were diagnosed with LTBI overseas and arrived in the US during 2007-2019. In the US, 45 939 (62.9%) completed, and 1985 (2.7%) initiated but did not complete a postarrival evaluation. Among these 47 924 children, 30 360 (63.4%) were retested for M tuberculosis infection. For 17 996 children with a positive overseas TST, 73.8% were negative when retested by IGRA. For 1051 children with a positive overseas IGRA, 58.0% were negative when retested by IGRA. Overall, among children who completed a postarrival evaluation, 18 544 (40.4%) were evaluated as having no evidence of TB infection, and 25 919 (56.4%) had their overseas LTBI diagnosis confirmed. Among the latter, 17 229 (66.5%) initiated and 9185 (35.4%) completed LTBI treatment. CONCLUSIONS: Requiring IGRA testing overseas could more effectively identify children who will benefit from LTBI treatment. However, IGRA reversions may occur, highlighting the need for individualized assessment for risk of infection, progression, and poor outcome when making diagnostic and treatment decisions. Strategies are needed to increase the proportions receiving a postarrival evaluation and completing LTBI treatment.


Assuntos
Emigrantes e Imigrantes , Tuberculose Latente , Refugiados , Tuberculose , Criança , Humanos , Testes de Liberação de Interferon-gama/métodos , Tuberculose Latente/diagnóstico , Teste Tuberculínico/métodos
8.
Rev. cir. (Impr.) ; 73(5): 625-633, oct. 2021. ilus, tab
Artigo em Espanhol | LILACS | ID: biblio-1388870

RESUMO

Resumen Introducción: Debido a su eficacia en el tratamiento de la obesidad mórbida, el bypass gástrico (BPG) sigue siendo una intervención realizada frecuentemente. Sin embargo, un grupo reducido de pacientes puede desarrollar complicaciones nutricionales y metabólicas que no logran controlarse con un tratamiento médico óptimo. En estos casos, puede ser necesario reestablecer la continuidad del tracto gastrointestinal por medio de la reversión del BPG (R-BPG). Objetivo: Presentar las indicaciones y resultados obtenidos en una serie de pacientes sometidos a una R-BPG. Materiales y Método: Identificación y evaluación retrospectiva de todos los pacientes sometidos a una R-BPG en nuestra institución de manera consecutiva. Se registraron las características demográficas y antropométricas de la cirugía original y al momento de la reversión. Las complicaciones se registraron de acuerdo con la clasificación de Clavien-Dindo. Resultados: Se identificaron 7 pacientes en los cuales se realizó una R-BPG. En 2 casos la reversión fue por síndrome de intestino corto, en 3 casos por hipoglicemias severas refractarias a manejo médico y en 2 casos por diarrea crónica. La mediana de edad al momento de la reversión fue de 55 años. La mediana de tiempo desde la cirugía original hasta el momento de la reversión fue de 77 meses. La mediana de estadía hospitalaria fue de 6 días. No hubo complicaciones Clavien-Dindo ≥ III. La R-BPG logró revertir en todos los casos las complicaciones nutricionales y metabólicas. Conclusión: La restauración de la continuidad del tracto gastrointestinal permite el control de las complicaciones nutricionales y metabólicas.


Introduction: Due to its efficacy in the treatment of morbid obesity, roux-en-y gastric bypass (RYGB) continues to be a frequently performed intervention. However, a small group of patients may develop nutritional and metabolic complications that cannot be controlled with optimal medical treatment. In these cases, it may be necessary to reestablish the continuity of the gastrointestinal tract by reversing the RYGB (R-RYGB). Aim: To present the indications and results obtained in a series of patients who underwent to R-RYGB. Materials and Method: Identification and retrospective evaluation of all patients who underwent consecutive R-RYGB in our institution. Demographic and anthropometric characteristics of the original surgery and at the time of the reversal were recorded. Complications were classified according to Clavien-Dindo classification. Results: Seven patients were identified in whom an R-RYGB was performed. In 2 cases the reversal was due to short bowel syndrome, in 3 cases due to severe hypoglycemia refractory to medical treatment and in 2 cases due to chronic diarrhea. The median age at the time of the reversal was 55 years. The median time from primary surgery to reversal was 77 months. The median hospital stay was 6 days. There were no Clavien-Dindo complications ≥ III. The R-RYGB was able to reverse nutritional and metabolic complications in all cases. Conclusion: Restoring the continuity of the gastrointestinal tract allows control of nutritional and metabolic complications.


Assuntos
Humanos , Esofagoplastia/métodos , Cirurgia Bariátrica/efeitos adversos , Cirurgia Bariátrica/métodos , Próteses e Implantes , Obesidade Mórbida/cirurgia
9.
Rev. biol. trop ; Rev. biol. trop;69(3)sept. 2021.
Artigo em Inglês | LILACS, SaludCR | ID: biblio-1387666

RESUMO

Abstract Introduction: Testicular histology constitutes one of the least explored aspects in frogs of the genus Atelopus. This taxonomic group shows an alarming population decline; therefore, its reproductive biology is one of the greatest topics of interest for its conservation. Objective: To describe the testicular morphology and the spermatogenetic lineage cells in adult males of Atelopus laetissimus, Atelopus nahumae, and Atelopus carrikeri in the Sierra Nevada de Santa Marta, Colombia. Methods: During June - July 2017 and 2018, sampling was conducted in the localities of San Lorenzo and Páramo Cebolletas, Sierra Nevada de Santa Marta (SNSM), to collect 15 adult males, 5 per species. Testes samples were fixed in Bouin to be processed by the standard paraffin-embedding technique. Histological sections (3 μm) were stained with Hematoxylin-eosin and Mallory-Heidenhain-Azan-Gomori's. For the description and photographic register of the germ cells, the photonic microscopy technique was used with the differential interference contrast system. Results: The testes are oval organs, compact, light yellow color, and with little vascularization. Externally, they are surrounded by a thin albuginea tunic constituted by regular dense connective tissue. Inside this layer, they are composed of numerous seminiferous tubules of hexagonal contour, in which germ cell cysts are distinguished at different stages of spermatogenesis (spermatogonia I and II, spermatocyte I and II, and early and late spermatids) and spermiogenesis (spermatozoa in fascicles and free spermatozoa). Separating the seminiferous structures is the interstitial tissue in which Leydig cells and blood vessels stand out. Additionally, in the cranial part of the testis, the Bidder's organ was found, formed by two distinguishable regions, the cortex and the medulla. In the cortex, there are previtellogénic oocytes of different sizes surrounded by a monolayer of flat follicular cells. For its part, the medullary region is the connective tissue that nourishes the oocytes and is constituted by blood capillaries. Conclusions: The gonads of the three species analyzed present a cystic cellular organization similar to other anurans, where all stages of spermatogenesis and spermiogenesis were identified, possibly indicating a continuous reproductive activity. Likewise, the Bidder's organ is reported for the first time in the three Atelopus species, which allows suggesting a possible sexual reversion in case of a population decrease of females as a reproductive strategy.


Resumen Introducción: La histología testicular constituye uno de los aspectos menos explorados en las ranas del género Atelopus. Este grupo taxonómico ostenta un declive poblacional alarmarte, es por ello, que su biología reproductiva resulta uno de los temas de mayor interés para su conservación. Objetivo: Describir la morfología testicular y las células del linaje espermatogénico en machos adultos de Atelopus laetissimus, Atelopus nahumae y Atelopus carrikeri en la Sierra Nevada de Santa Marta, Colombia. Métodos: Durante Junio - Julio de 2017 y 2018 se realizaron muestreos en las localidades de San Lorenzo y Páramo Cebolletas, Sierra Nevada de Santa Marta (SNSM), para recolectar 15 machos adultos, 5 por especie. Las muestras de testículo se fijaron en Bouin para ser procesadas mediante la técnica estándar de inclusión en parafina. Las secciones histológicas (3 μm) se tiñeron con Hematoxilina-eosina y Mallory-Heidenhain-Azan-Gomori's. Para la descripción y registro fotográfico de las células germinales, se utilizó la técnica de microscopía fotónica con el sistema de contraste diferencial de interferencia. Resultados: Los testículos son órganos ovalados, compactos, de color amarillo claro y con poca vascularización. Externamente, están rodeados por una delgada túnica albugínea constituida por tejido conectivo denso regular. Al interior de esta capa se componen por numerosos túbulos seminíferos de contorno hexagonal, en los que se distinguen quistes de células germinativas en diferentes etapas de la espermatogénesis (espermatogonia I y II, espermatocito I y II y espermátidas tempranas y tardías) y espermiogénesis (espermatozoides en fascículos y espermatozoides libres). Separando las estructuras seminíferas se halla el tejido intersticial en el que se destacan las células de Leydig y los vasos sanguíneos. Adicionalmente, en la parte craneal del testículo se encontró el órgano de bidder formado por dos regiones diferenciables, la corteza y la medula. En la corteza se aprecian ovocitos previtelogénicos en diferente tamaño rodeados por una monocapa de células foliculares planas. Por su parte, la región medular es el tejido conectivo que nutre los ovocitos y está constituido por capilares sanguíneos. Conclusiones: Las gónadas de las tres especies analizadas presentan una organización celular quística de manera similar con otros anuros, donde se identificó todos los estadios de la espermatogénesis y espermiogénesis indicando posiblemente una actividad reproductiva continua. Así mismo, se reporta por primera vez el órgano de bidder en las tres especies de Atelopus, lo cual permite sugerir una posible reversión sexual en caso de una disminución poblacional de las hembras como una estrategia reproductiva.


Assuntos
Animais , Ranidae/anatomia & histologia , Testículo
10.
Rev. biol. trop ; Rev. biol. trop;69(2)jun. 2021.
Artigo em Inglês | LILACS, SaludCR | ID: biblio-1387647

RESUMO

Abstract Introduction: Rhinella schneideri is a toad widely distributed in South America and its poison is characterized by inducing cardiotoxicity and neurotoxicity. Objective: In this work, we investigated pharmacological strategies to attenuate the peripheral neurotoxicity induced by R. schneideri poison in avian neuromuscular preparation. Methods: The experiments were carried out using isolated chick biventer cervicis preparation subjected to field stimulation for muscle twitches recordings or exposed to acetylcholine and potassium chloride for contracture responses. Results: Poison (10 μg/ml) produced complete neuromuscular blockade in chick biventer cervicis preparation within approximately 70 min incubation (times for 50 and 90 % blockade: 15 ± 3 min and 40 ± 2 min, respectively; P < 0.05, N= 5); contracture responses to exogenous acetylcholine and KCl were unaffected by poison indicating no specificity with postsynaptic receptors or myotoxicity, respectively. Poison (10 μg/ml)-induced neuromuscular blockade was not prevented by heparin (5 and 150 IU/ml) under pre- or post-treatment conditions. Incubation at low temperature (23-25 °C) abolished the neuromuscular blockade; after raising the temperature to 37 °C, the complete neuromuscular blockade was slightly slower than that seen in preparations directly incubated at 37 °C (times for 50 and 90 % blockade: 23 ± 2 min and 60 ± 2.5 min, respectively; P < 0.05, N= 4). Neostigmine (3.3 μM) did not reverse the neuromuscular blockade in BC preparation whereas 3,4-diaminopyridine (91.6 μM) produced a partial and sustained reversal of the twitch responses (29 ± 7.8 % of maximal reversal reached in approximately 40 min incubation; P < 0.05, N= 4). Conclusions: R. schneideri poison induces potent peripheral neurotoxicity in vitro which can be partially reversible by 3,4-diaminopyridine.


Resumen Introducción: Rhinella schneideri está ampliamente distribuida en Suramérica y su veneno es caracterizado por inducir cardiotoxicidad y neurotoxicidad. Objetivo: En este trabajo, investigamos estrategias farmacológicas para atenuar la neurotoxicidad periférica inducida por el veneno de R. schneideri en preparaciones neuromusculares de aves. Métodos: Los experimentos fueron realizados usando preparaciones de biventer cervicis de pollos sometidas a estimulación de campo para el registro de las contracciones musculares o expuestas a la acetilcolina y al cloruro de potasio para la respuesta contractural. Resultados: El veneno (10 µg/ml) provocó un bloqueo neuromuscular completo en las preparaciones después de aproximadamente 70 min de incubación (tiempos para 50 y 90 % de bloqueo: 15 ± 3 min y 40 ± 2 min, respectivamente; P < 0.05, N = 5); las contracturas en respuesta a la acetilcolina y el KCl exógenos no fueron afectadas por el veneno, indicando que no hay una interacción especifica con receptores postsinápticos o miotoxicidad respectivamente. El bloqueo neuromuscular causado por el veneno (10 µg/ml) no fue prevenido por la heparina (5 y 150 UI/ml) bajo condiciones pre y post-tratamiento. La incubación a bajas temperaturas (23-25 ºC) abolió el bloqueo neuromuscular; después de aumentar la temperatura a 37 ºC, el bloqueo neuromuscular total fue levemente más lento que el visto en preparaciones directamente incubadas a 37 ºC (tiempos para 50 y 90 % de bloqueo: 23 ± 2 min y 60 ± 2.5 min, respectivamente; P < 0.05, N= 4). Neostigmina (3.3 µM) no revirtió el bloqueo neuromuscular, mientras que 3.4-diaminopiridina (91.6 µM) produjo una reversión parcial y sostenida de las respuestas neuromusculares (29 ± 7.8 % de la reversión máxima alcanzada en aproximadamente 40 min de incubación; P < 0.05, N = 4). Conclusiones: El veneno de R. schneideri indujo neurotoxicidad periférica potente in vitro, el cual puede ser revertido por 3.4-diaminopiridina.


Assuntos
Animais , Bufo marinus , Bloqueio Neuromuscular , Aves , Brasil
11.
Phytopathology ; 111(9): 1541-1550, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33591814

RESUMO

Silverleaf is caused by the fungus Chondrostereum purpureum, which produces wood necrosis and foliar silvering in woody plants. Field observations and studies in apple have shown the reversion of foliar symptoms. Because plants were clones and received identical agronomical management, it was hypothesized that reversion is driven by endophytic microbiota. Thus, the objectives of this study were to compare healthy, diseased, and reverted plants with respect to their physiology, endophytic microbial communities, antagonistic ability of their endophytes against C. purpureum, and defense genes expression. Water potential, stomatal conductance, chlorophyll content, and fluorescence were measured. Endophytic bacterial and fungal DNA were analyzed by denaturing gradient gel electrophoresis, and community richness and similarity were calculated. Wood cores were collected and bacterial and fungal endophytes were isolated and confronted with C. purpureum-virulent strains in dual-culture assays. Defense genes expression was measured by quantitative PCR. Results indicated that there were no differences in physiological parameters between healthy and reverted plants, except for fluorescence, and both type of plants differed from diseased ones. Bacterial and fungal community richness was similar in healthy and reverted plants and higher than in diseased ones. Endophytes from reverted and healthy plants showed high antagonism to C. purpureum. Furthermore, nonexpressor of pathogenesis-related gene 1 expression was upregulated in reverted plants, whereas phenylalanine ammonia lyase and polygalacturonase-inhibiting protein genes showed higher values in diseased plants. Overall, physiological, molecular, and microbial characteristics were similar between healthy and reverted plants, and both differed from diseased ones. Therefore, reversion of symptoms is associated with changes in the endophytic microbiota, which seems to be a promising source of biological control agents against C. purpureum.


Assuntos
Malus , Doenças das Plantas
12.
Medicina (B.Aires) ; Medicina (B.Aires);80(4): 405-410, ago. 2020. graf
Artigo em Espanhol | LILACS | ID: biblio-1154838

RESUMO

Resumen Los anticoagulantes orales directos (AOD), entre ellos dabigatrán, poseen un perfil riesgo-beneficio favorable comparados con warfarina y además no requieren monitoreo del efecto anticoagulante. Sin embargo, en ocasiones de sangrado con amenaza de vida o requerimiento de procedimiento quirúrgico de emergencia, es de gran utilidad revertir inmediatamente el efecto anticoagulante. Idarucizumab, fragmento de un anticuerpo monoclonal humanizado, revierte inmediatamente el efecto de dabigatrán y es actualmente el único agente reversor de un AOD disponible en Argentina. Presentamos una serie de 8 pacientes a los que se les administró idarucizumab para revertir el efecto de dabigatrán. Todos eran mayores de 65 años, recibían 110 o 150 mg cada 12 horas de dabigatrán y 7/8 estaban anticoagulados por fibrilación auricular; tres tenían indicación discutida para AOD y otro, una dosis mayor a la recomendada. Dos requirieron reversión debido a una cirugía de urgencia, y 6 tuvieron sangrado con amenaza de vida: tres hemorragias digestivas y tres sangrados intra-craneanos (en dos ocasiones traumático). En todos los casos se observó normalización de la hemostasia quirúrgica o control de sangrado crítico. No se observaron complicaciones trombóticas posteriores a la administración del antídoto. Dos fallecieron dentro de los 30 días de la administración por causas no relacionadas con la reversión. Ninguno de nuestros pacientes requirió administración de una segunda dosis de idarucizumab. Nuestro resultado es similar a lo informado en la literatura internacional.


Abstract Direct oral anticoagulants (DOACs), among them dabigatran, have a favorable benefit-risk profile compared with warfarin, and no monitoring of the anticoagulant effect is required. However, reversing the anticoagulant effect immediately is very useful in cases of life-threatening bleeding and emergency surgical procedure requirement. Idarucizumab, a humanized monoclonal antibody fragment, is currently the only reversal agent of a DOAC available in Argentina. Idarucizumab immediately reverse the effect of dabigatran. We present a series of 8 real-life clinical cases who received idarucizumab to reverse the effect of dabigatran. All of the patients were older than 65 years, were receiving 110 or 150 mg every 12 hours of dabigatran and 7/8 were anticoagulated because of atrial fibrillation. Three had a debatable indication for DOACs and another, a higher dose than recommended. Two required reversal due to emergency surgery, and 6 cases had life-threatening bleeding: three gastrointestinal hemorrhages and three intracranial bleeding (Two had a head trauma). In all cases normalization of surgical hemostasis or control of critical bleeding was observed. No hemorrhagic or thrombotic complications were observed after antidote administration. Two died within 30 days of administration of idarucizumab, due to causes unrelated to the reversal. None of our patients required administration of a second dose of idarucizumab. Our result is similar to that reported in international literature.


Assuntos
Humanos , Anticorpos Monoclonais Humanizados/uso terapêutico , Argentina , Dabigatrana , Anticoagulantes
13.
Int J Mol Sci ; 21(7)2020 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-32244518

RESUMO

Cannabidiol (CBD) has been used to treat a variety of cancers and inflammatory conditions with controversial results. In previous work, we have shown that breast cancer MCF-7 cells, selected by their response to inflammatory IL-1ß cytokine, acquire a malignant phenotype (6D cells) through an epithelial-mesenchymal transition (EMT). We evaluated CBD as a potential inhibitor of this transition and inducer of reversion to a non-invasive phenotype. It decreased 6D cell viability, downregulating expression of receptor CB1. The CBD blocked migration and progression of the IL-1ß-induced signaling pathway IL-1ß/IL-1RI/ß-catenin, the driver of EMT. Cannabidiol reestablished the epithelial organization lost by dispersion of the cells and re-localized E-cadherin and ß-catenin at the adherens junctions. It also prevented ß-catenin nuclear translocation and decreased over-expression of genes for ∆Np63α, BIRC3, and ID1 proteins, induced by IL-1ß for acquisition of malignant features. Cannabidiol inhibited the protein kinase B (AKT) activation, a crucial effector in the IL-1ß/IL-1RI/ß-catenin pathway, indicating that at this point there is crosstalk between IL-1ß and CBD signaling which results in phenotype reversion. Our 6D cell system allowed step-by-step analysis of the phenotype transition and better understanding of mechanisms by which CBD blocks and reverts the effects of inflammatory IL-1ß in the EMT.


Assuntos
Neoplasias da Mama/metabolismo , Canabidiol/farmacologia , Citocinas/metabolismo , Interleucina-1beta/metabolismo , Neoplasias da Mama/genética , Caderinas/metabolismo , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Regulação para Baixo , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Células MCF-7 , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Cicatrização , beta Catenina/metabolismo
14.
Actas Urol Esp (Engl Ed) ; 44(5): 314-320, 2020 Jun.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-32147350

RESUMO

Given the nature of the multiple causes of male infertility, some of them are «reversible¼ and can be managed with a surgical procedure to recover, in some cases, the fertilizing capacity of the male reproductive tract. With appropriate use of diagnostic tools and clinical judgement, the physician can identify the ideal candidates for these procedures. Together with the expertise and experience of the surgeon, these treatments can manage to resolve the barrier, and men may become fertile again. In this chapter, we will review some of the most commonly used surgical procedures for the treatment of male infertility and make a brief description of their technical details.


Assuntos
Infertilidade Masculina/cirurgia , Humanos , Masculino , Procedimentos Cirúrgicos Urológicos Masculinos/métodos
15.
Vaccines (Basel) ; 8(1)2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-32121666

RESUMO

The safety and genetic stability of V4020, a novel Venezuelan Equine Encephalitis Virus (VEEV) vaccine based on the investigational VEEV TC-83 strain, was evaluated in mice. V4020 was generated from infectious DNA, contains a stabilizing mutation in the E2-120 glycoprotein, and includes rearrangement of structural genes. After intracranial inoculation (IC), replication of V4020 was more attenuated than TC-83, as documented by low clinical scores, inflammation, viral load in brain, and earlier viral clearance. During the first 9 days post-inoculation (DPI), genes involved in inflammation, cytokine signaling, adaptive immune responses, and apoptosis were upregulated in both groups. However, the magnitude of upregulation was greater in TC-83 than V4020 mice, and this pattern persisted till 13 DPI, while V4020 gene expression profiles declined to mock-infected levels. In addition, genetic markers of macrophages, DCs, and microglia were strongly upregulated in TC-83 mice. During five serial passages in the brain, less severe clinical manifestations and a lower viral load were observed in V4020 mice and all animals survived. In contrast, 13.3% of mice met euthanasia criteria during the passages in TC-83 group. At 2 DPI, RNA-Seq analysis of brain tissues revealed that V4020 mice had lower rates of mutations throughout five passages. A higher synonymous mutation ratio was observed in the nsP4 (RdRP) gene of TC-83 compared to V4020 mice. At 2 DPI, both viruses induced different expression profiles of host genes involved in neuro-regeneration. Taken together, these results provide evidence for the improved safety and genetic stability of the experimental V4020 VEEV vaccine in a murine model.

16.
Molecules ; 24(2)2019 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-30642049

RESUMO

Myocardial infarction (MI) initiates an inflammatory response that promotes both beneficial and deleterious effects. The early response helps the myocardium to remove damaged tissue; however, a prolonged later response brings cardiac remodeling characterized by functional, metabolic, and structural pathological changes. Current pharmacological treatments have failed to reverse ischemic-induced cardiac damage. Therefore, our aim was to study if clofibrate treatment was capable of decreasing inflammation and apoptosis, and reverse ventricular remodeling and MI-induced functional damage. Male Wistar rats were assigned to (1) Sham coronary artery ligation (Sham) or (2) Coronary artery ligation (MI). Seven days post-MI, animals were further divided to receive vehicle (V) or clofibrate (100 mg/kg, C) for 7 days. The expression of IL-6, TNF-α, and inflammatory related molecules ICAM-1, VCAM-1, MMP-2 and -9, nuclear NF-kB, and iNOS, were elevated in MI-V. These inflammatory biomarkers decreased in MI-C. Also, apoptotic proteins (Bax and pBad) were elevated in MI-V, while clofibrate augmented anti-apoptotic proteins (Bcl-2 and 14-3-3ε). Clofibrate also protected MI-induced changes in ultra-structure. The ex vivo evaluation of myocardial functioning showed that left ventricular pressure and mechanical work decreased in infarcted rats; clofibrate treatment raised those parameters to control values. Echocardiogram showed that clofibrate partially reduced LV dilation. In conclusion, clofibrate decreases cardiac remodeling, decreases inflammatory molecules, and partly preserves myocardial diameters.


Assuntos
Clofibrato/farmacologia , Hipolipemiantes/farmacologia , Inflamação/patologia , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/patologia , Remodelação Ventricular/efeitos dos fármacos , Animais , Citocinas/metabolismo , Modelos Animais de Doenças , Inflamação/metabolismo , Mediadores da Inflamação/metabolismo , Infarto do Miocárdio/metabolismo , PPAR alfa/metabolismo , Roedores
17.
Arch Biochem Biophys ; 663: 173-182, 2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30639329

RESUMO

Muscle wasting or atrophy is extensively associated with human systemic diseases including diabetes, cancer, and kidney failure. Accumulating evidence from transcriptional profiles has noted that a common set of genes, termed atrogenes, is modulated in atrophying muscles. However, the transcriptional changes that trigger the reversion or attenuation of muscle atrophy have not been characterized at the molecular level until now. Here, we applied cDNA microarrays to investigate the transcriptional response of androgen-sensitive Levator ani muscle (LA) during atrophy reversion. Most of the differentially expressed genes behaved as atrogenes and responded to castration-induced atrophy. However, seven genes (APLN, DUSP5, IGF1, PIK3IP1, KLHL38, PI15, and MKL1) did not respond to castration but instead responded exclusively to testosterone replacement. Considering that almost all proteins encoded by these genes are associated with the reversion of atrophy and may function as regulators of cell proliferation/growth, our results provide new perspectives on the existence of anti-atrogenes.


Assuntos
Androgênios/metabolismo , Perfilação da Expressão Gênica , Músculo Esquelético/metabolismo , Atrofia Muscular/metabolismo , Animais , Jejum , Terapia de Reposição Hormonal , Masculino , Camundongos , Modelos Biológicos , Músculo Esquelético/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Orquiectomia , Ratos , Ratos Wistar , Testosterona/administração & dosagem
18.
Plant Cell Environ ; 42(2): 606-617, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30216475

RESUMO

Vegetation shade is characterized by marked decreases in the red/far-red ratio and photosynthetic irradiance. The activity of phytochrome in the field has typically been described by its photoequilibrium, defined by the photochemical properties of the pigment in combination with the spectral distribution of the light. This approach represents an oversimplification because phytochrome B (phyB) activity depends not only on its photochemical reactions but also on its rates of synthesis, degradation, translocation to the nucleus, and thermal reversion. To account for these complex cellular reactions, we used a model to simulate phyB activity under a range of field conditions. The model provided values of phyB activity that in turn predicted hypocotyl growth in the field with reasonable accuracy. On the basis of these observations, we define two scenarios, one is under shade, in cloudy weather, at the extremes of the photoperiod or in the presence of rapid fluctuations of the light environment caused by wind-induced movements of the foliage, where phyB activity departs from photoequilibrium and becomes affected by irradiance and temperature in addition to the spectral distribution. The other scenario is under full sunlight, where phyB activity responds mainly to the spectral distribution of the light.


Assuntos
Proteínas de Arabidopsis/metabolismo , Fitocromo B/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Arabidopsis/efeitos da radiação , Hipocótilo/crescimento & desenvolvimento , Luz , Modelos Biológicos , Fotoperíodo , Luz Solar
19.
Rev. colomb. cienc. pecu ; 31(4): 304-314, oct.-dic. 2018. tab, graf
Artigo em Inglês | LILACS | ID: biblio-985484

RESUMO

Abstract Background: Production of monosex cultures of females is desirable in commercial aquaculture of certain species due to their higher growth rate. Ideally, females should be free of exogenous hormones. The initial step to produce hormone-free all-female offspring is masculinization of normal females to create sex reversed animals, called neomales, which are then be bred with normal females obtaining all-female offspring. Objective: To masculinize Rhamdia quelen fry by adding 17α-methyltestosterone (MT) hormone to the feed. Methods: Larvae of R. quelen were fed diets supplemented with 60, 80, or 100 mg MT/kg feed for 21 days. A control group was fed the same diet free of MT. At 150 days post-hatching, 30 fish of each treatment group were euthanized to evaluate gonadal changes using histological techniques. Results: MT significantly affected the differentiation of female gonads in the 60 and 80 mg MT/kg feed groups. Sex reversal was observed in all MT treatment groups, with 50, 40, and 20% neomales produced with 60, 80, and 100 mg MT/kg feed, respectively. Intersex gonads were observed only in the masculinization treatment groups. Inhibitory effects on gonadal development of females and males were observed at the highest MT doses. Conclusion: Dietary administration of MT effectively masculinizes R. quelen fry; however, the lowest dose of 60 mg/kg feed is recommended, since higher doses have inhibitory effects on gonadal development in both sexes.


Resumen Antecedentes: Debido a su mayor tasa de crecimiento, la producción de peces femeninos monosexo es deseable en acuicultura comercial de determinadas especies. Idealmente, las hembras deben estar libres de hormonas exógenas. El paso inicial para generar descendencia femenina libre de hormonas es la masculinización de hembras genéticas para producir animales sexualmente revertidos, llamados neomachos, los cuales se aparean luego con hembras genéticas para producir descendencia femenina. Objetivo: Masculinizar larvas de Rhamdia quelen con 17α-metiltestosterona (MT) incorporada en el alimento. Métodos: Larvas de R. quelen fueron alimentadas con dietas suplementadas con 60, 80 y 100 mg de MT/kg de alimento durante 21 días. Un grupo control recibió la misma dieta, sin MT. A los 150 días pos-eclosión, 30 peces de cada tratamiento fueron eutanasiados para evaluación gonadal mediante técnicas histológicas. Resultados: La MT afectó significativamente la diferenciación de las gónadas femeninas en las dosis de 60 y 80 mg MT/kg de alimento. El cambio de sexo se observó en los tratamientos con las dosis de 60, 80 y 100 mg MT/kg alimento, con 50, 40 y 20% de neomachos, respectivamente. En los tratamientos de masculinización se observaron gónadas intersexuales. En las dosis más altas de MT se observó inhibición del desarrollo gonadal de hembras y machos. Conclusiones: El suministro dietario de MT masculinizó las larvas de R. quelen. Se recomienda usar 60 mg/kg, ya que dosis mayores tienen efectos inhibidores en el desarrollo gonadal para ambos sexos.


Resumo Antecedentes: O cultivo monossexo feminino é desejável na aquicultura comercial de determinadas espécies devido à maior taxa de crescimento. Idealmente, as fêmeas devem ser livres de hormônios exógenos. O passo inicial para gerar descendências femininas livres destes hormônios é a masculinização de fêmeas normais para produzir animais revertidos sexualmente, os chamados neomachos. Os neomachos podem então ser cruzados com fêmeas normais para a produção de descendências femininas. Objetivo: Masculinizar larvas de R. quelen utilizando o hormônio 17α-metiltestosterona (MT) incorporado no alimento. Métodos: Larvas de R. quelen foram alimentadas com dietas suplementadas com MT nas doses de 60, 80 ou 100 mg/kg de alimento durante 21 dias. Um grupo controle foi alimentado com dieta similar livre de MT. Aos 150 dias pós-eclosão, 30 peixes de cada grupo de tratamento foram eutanasiados para avaliação gonadal através de técnicas histológicas. Resultados: O uso de MT afetou significativamente a diferenciação das gônadas femininas nas doses 60 e 80 mg/kg de alimento. A reversão sexual foi observada em todos os grupos tratados com MT, gerando 50, 40 e 20% de neomachos nas doses 60, 80 e 100 mg MT/kg de alimento, respectivamente. Gônadas intersexuais foram observadas somente nos tratamentos masculinizantes. Nas maiores doses de MT, efeitos inibitórios de desenvolvimento gonadal foram observados em fêmeas e machos. Conclusão: A administração dietética de MT efetivamente masculinizou larvas de R. quelen. No entanto, a dose mais baixa de 60 mg/kg de alimento é recomendada devido aos efeitos inibitórios das doses mais elevadas de MT no desenvolvimento gonadal de ambos os sexos.

20.
Exp Toxicol Pathol ; 69(7): 496-503, 2017 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-28487049

RESUMO

Regulating mechanisms of fibrosis is an important goal in the treatment of fibrosis and liver cirrhosis. The role of arginine vasopressin (AVP) in promoting fibrosis in several organs has been well documented. However, the result of an AVP deficiency during liver fibrosis has not been reported. We herein study the effects of an AVP deficiency, which was induced by neurointermediate pituitary lobectomy (NIL), on liver cirrhosis and liver cirrhosis reversion. Hamsters were intact (control) or underwent CCl4-induced cirrhosis, the latter animals divided into four groups: Cirrhotic, NIL-cirrhotic, Cirrhotic-reversion (R) and NIL-cirrhotic-R. Liver function, liver histopathology (including the fibrosis area and collagen types) and liver expression of MMP-13 and TIMP-2 were assessed. Results show that the AVP deficiency decreased the levels of alkaline phosphatase in serum and the expression of type I collagen and TIMP-2, and increased type III collagen deposition, MMP-13 expression and the size of regeneration nodules in NIL-cirrhotic and NIL-cirrhotic-R animals. A significantly greater recovery was found in the NIL-cirrhotic-R than the Cirrhotic-R group. We conclude that an AVP deficiency participates importantly in hamster liver regeneration by: 1) prompting the fibroblasts to produce type III collagen deposit, 2) influencing the activity of AP from bile duct cells, and 3) inhibiting TIMP-2 expression while favoring the fibrolytic activity of MMP-13.


Assuntos
Arginina Vasopressina/deficiência , Cirrose Hepática/patologia , Regeneração Hepática/fisiologia , Animais , Tetracloreto de Carbono/toxicidade , Cricetinae , Hipofisectomia , Masculino
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