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Bovine viral diarrhea virus (BVDV) is a major pathogen worldwide, causing significant economic losses to the livestock sector. In Uruguay, BVDV seroprevalence at the farm level is >80%. In this work, 2546 serum, blood or tissue samples collected from animals suspected of being affected by BVD between 2015 and 2017 were analyzed by reverse transcription PCR and sequencing. Analysis of the BVDV genomic regions 5'UTR/Npro, Npro and E2 revealed that BVDV-1a, 1i and 2b circulate in the country, with BVDV-1a being the most prevalent subtype. Population dynamics studies revealed that BVDV-1a has been circulating in our herds since ~1990. This subtype began to spread and evolve, accumulating point mutations at a rate of 3.48 × 10-3 substitutions/site/year, acquiring specific genetic characteristics that gave rise to two local genetic lineages of BVDV-1a. These lineages are divergent from those circulating worldwide, as well as the vaccine strain currently used in Uruguay. The most notable differences between field and vaccine strains were found in the E2 glycoprotein, suggesting that the amino acid substitutions could result in failure of cross-protection/neutralization after vaccination. This is the first study that compares Uruguayan BVDV field and vaccine strains with other BVDV strains from throughout the world. The results obtained in this study will be very useful for developing a suitable immunization program for BVDV in Uruguay by identifying local field strains as candidates for vaccine development.
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Virus de la Diarrea Viral Bovina/clasificación , Mutación Puntual , Análisis de Secuencia de ARN/métodos , Sustitución de Aminoácidos , Animales , Bovinos , Virus de la Diarrea Viral Bovina/genética , Virus de la Diarrea Viral Bovina/inmunología , Evolución Molecular , Filogenia , Estudios Seroepidemiológicos , Uruguay , Proteínas del Envoltorio Viral/genética , Proteínas del Envoltorio Viral/inmunología , Vacunas Virales/inmunologíaRESUMEN
Bovine viral diarrhea (BVD) affects bovine production and reproduction causing significant economic losses all over the world. Two viral species has been recognized: BVDV-1 and BVDV-2, both distributed worldwide. Recently, novel specie of BVDV named HoBi-like pestivirus was discovered. The presence of BVDV was confirmed in 1996 in Uruguay, however, does not exist until today a schedule of compulsory vaccination along the country. Serological studies with samples from all Uruguayan herds were performed during 2000 and 2001 demonstrating that all of them were seropositive to BVDV with a mean prevalence of 69%. In addition, there have been no new studies done since those previously described and it is important to mention that the genetic diversity of BVD has never been described in Uruguay. Nowadays, there is strongly suspect that BVDV is one of the most important causes of reproductive failures in our herds. The aim of this study was to describe for the first time in Uruguay the genetic diversity of BVDV with samples collected from different regions along the country. Serological status of 390 non-vaccinated animals against BVDV with reproductive problems from farms of Rivera, Tacuarembó and Florida departments of Uruguay were studied. All herds were seropositive to BVDV and high proportion of animals were positive (298/390), while 4.1% (16/390) of the animals were positive to Antigen Capture ELISA test and Real Time PCR. Phylogenetic analysis performed with concatenated sequences from the 5'UTR and Npro genomic regions revealed that BVDV-1 and BVDV-2 are infecting our herds, being BVDV-1 the most frequently found. The major subtype was BVDV-1a, followed by BVDV-1i and BVDV-2b. This is the first study that describes the genetic diversity of BVDV in Uruguay and it will contribute to the elaboration of sanitization programs.
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Diarrea Mucosa Bovina Viral/virología , Virus de la Diarrea Viral Bovina/clasificación , Virus de la Diarrea Viral Bovina/genética , Variación Genética , Regiones no Traducidas 5' , Animales , Bovinos , Análisis por Conglomerados , Virus de la Diarrea Viral Bovina/aislamiento & purificación , Genotipo , Datos de Secuencia Molecular , Filogenia , ARN Viral/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Análisis de Secuencia de ADN , Homología de Secuencia , Uruguay , Proteínas Virales/genéticaRESUMEN
INTRODUCTION: Closing wedge high tibial osteotomy (CW-HTO) is a surgical option for active patients with medial knee pain and mild-moderate osteoarthritis with varus limb deformity. Despite its good reported results, this technique has been losing popularity. The aim of this study was to analyse the survival rate, clinical functional outcomes and radiological results of CW-HTO. METHODS: It is a retrospective case series study. Seventy patients with primary knee osteoarthritis, operated on between 2010 and 2020 in a single Spanish tertiary hospital using the CW-HTO technique and with a minimum follow-up of 2 years were analysed. RESULTS: Survival rate was 87.6% and 75.5% after a follow-up of 5 and 10 years respectively. Functional outcomes were good-to-excellent (KSS 77.7/100 and OKS 35.6/48) and good pain control (VAS 3.9/10) and high satisfaction (7.2/10) were achieved. Limb varus malalignment was significantly corrected (mean postoperative HKA angle 177.6° and MPTA 90.7°). However, 30% of patients presented hypocorrection, which was associated with inferior survival, functionality and satisfaction. CONCLUSION: CW-HTO technique can be useful for patients with knee osteoarthritis and varus limb. It allows to correct varus malalignment while achieving good-to-excellent functional outcomes, good pain control, high patient satisfaction and acceptable medium-long term survival rate. However, it is associated with a non-negligible risk of hypocorrection or medial hinge disruption.
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INTRODUCTION: Closing wedge high tibial osteotomy (CW-HTO) is a surgical option for active patients with medial knee pain and mild-moderate osteoarthritis with varus limb deformity. Despite its good reported results, this technique has been losing popularity. The aim of this study was to analyse the survival rate, clinical functional outcomes and radiological results of CW-HTO. METHODS: It is a retrospective case series study. Seventy patients with primary knee osteoarthritis, operated on between 2010 and 2020 in a single Spanish tertiary hospital using the CW-HTO technique and with a minimum follow-up of 2 years were analysed. RESULTS: Survival rate was 87,6% and 75,5% after a follow-up of 5 and 10 years respectively. Functional outcomes were good-to-excellent (KSS 77.7/100 and OKS 35.6/48) and good pain control (VAS 3.9/10) and high satisfaction (7.2/10) were achieved. Limb varus malalignment was significantly corrected (mean postoperative HKA angle 177,6° and MPTA 90,7°). However, 30% of patients presented hypocorrection, which was associated with inferior survival, functionality and satisfaction. CONCLUSION: CW-HTO technique can be useful for patients with knee osteoarthritis and varus limb. It allows to correct varus malalignment while achieving good-to-excellent functional outcomes, good pain control, high patient satisfaction and acceptable medium-long term survival rate. However, it is associated with a non-negligible risk of hypocorrection or medial hinge disruption.
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We describe the use of unique microcapsules that may be degraded by the actions of bacteria. These microcapsules are approximately 35 mum in diameter, are composed of natural protein, and may be filled with a variety of actives. We describe the use of antimicrobial actives such as farnesol and methylparaben to demonstrate that their release by the degradative actions of axillary bacteria such as Corynebacterium minutissimum, C. urealyticum, and Staphylococcus epidermidis leads to their demise. These microcapsules may be used in consumer products such as deodorants and antiperpirants that may, under actual use conditions, control malodor.
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BACKGROUND: The family of G protein coupled receptors is the largest and perhaps most functionally diverse class of cell-surface receptors. Due to the difficulty of obtaining structural data on membrane proteins there is little information on which to base an understanding of ligand structure-activity relationships, the effects of receptor mutations and the mechanism(s) of signal transduction in this family. We therefore set out to develop a structural model for one such receptor, the human angiotensin II receptor. RESULTS: An alignment between the human angiotensin II (type 1; hAT1), human beta 2 adrenergic, human neurokinin-1, and human bradykinin receptors, all of which are G protein coupled receptors, was used to generate a three-dimensional model of the hAT1 receptor based on bacteriorhodopsin. We observed a region within the model that was congruent with the biogenic amine binding site of beta 2, and were thus able to dock a model of the hAT1 antagonist L-158,282 (MK-996) into the transmembrane region of the receptor model. The antagonist was oriented within the helical domain by recognising that the essential acid functionality of this antagonist interacts with Lys199. The structural model is consistent with much of the information on structure-activity relationships for both non-peptide and peptide ligands. CONCLUSIONS: Our model provides an explanation for the conversion of the antagonist L-158,282 (MK-996) to an agonist by the addition of an isobutyl group. It also suggests a model for domain motion during signal transduction. The approach of independently deriving three-dimensional receptor models and pharmacophore models of the ligands, then combining them, is a powerful technique which helps validate both models.
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Angiotensina II/metabolismo , Angiotensina I/metabolismo , Antagonistas de Receptores de Angiotensina , Proteínas de Unión al GTP/metabolismo , Receptores de Angiotensina/agonistas , Secuencia de Aminoácidos , Humanos , Modelos Estructurales , Datos de Secuencia MolecularRESUMEN
The efficiency of hybridoma formation and growth after cell fusion can be much improved by fractionation of the mouse splenocytes. A simple procedure is described in which splenocytes with a specific gravity of more than 1.065 g/cm3 are selected by centrifugation on a Percoll gradient. The resulting cell suspension is largely depleted of macrophages and fibroblasts while the cell viability is improved. In fusion experiments performed with these cells, overgrowth of hybridomas by macrophages, fibroblasts and P-cells is avoided. The fusion efficiency and the frequency of immunoglobulin-secreting hybridomas is increased compared with fusions carried out with unfractionated spleen cells.
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Células Productoras de Anticuerpos/inmunología , Fusión Celular , Separación Celular/métodos , Hibridomas/inmunología , Animales , Células Productoras de Anticuerpos/citología , Supervivencia Celular , Centrifugación por Gradiente de Densidad/métodos , Humanos , Hibridomas/citología , Inmunoglobulinas/biosíntesis , Ratones , Ratones Endogámicos BALB C , Povidona , Dióxido de Silicio , Bazo/citología , Bazo/inmunologíaRESUMEN
Proline and quaternary ammonium compounds (QAC), in addition to being N-rich, are known to accumulate in plants under different environmental stress conditions. The accumulation of N-rich compounds in plants has been shown to confer stress resistance. The aim of our work is two-fold: first, to study the influence of temperature on proline, QAC, and choline metabolism in tomato leaves; and second, to investigate the relationship between N source applied (NO3- or NH4+) and thermal stress resistance in these plants. To do this, experiments were conducted at three different temperatures (10 degrees C, 25 degrees C, 35 degrees C); at each temperature half of the plants received NO3-, and the other half received NH4+. At 35 degrees C the plants had the lowest biomass production with respect to 25 degrees C (optimal temperature) and 10 degrees C (cold stress), suggesting that tomato plants were most affected by heat stress. At 35 degrees C, there were also high levels of choline and proline due to the activation of Delta1-pyrroline-5-carboxylate synthetase (P5CS) and ornithine aminotransferase (OAT), and simultaneous inhibition of proline dehydrogenase (PDH) and proline oxidase (PO). However, plants with NH4+ as the N source exhibited reduced growth with respect to the plants fed with NO3-. This is interesting because, under heat stress (35 degrees C), biomass production, as well as proline and choline accumulation, in NH4+ fed plants was higher than in NO3- fed plants. From this, we concluded that tomato plants fed with NH4+ as the N source show higher tolerance to heat stress (35 degrees C) than plants fed with NO3-.
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Calor , Nitrógeno/metabolismo , Prolina/metabolismo , Compuestos de Amonio Cuaternario/metabolismo , Solanum lycopersicum/metabolismo , Análisis de Varianza , Colina/metabolismo , Solanum lycopersicum/química , Solanum lycopersicum/crecimiento & desarrollo , TemperaturaRESUMEN
In view of the essential role of phenolic compounds in the development of pathogen resistance in plants, and given the influence that fungicides exert over phenolic metabolism, the aim of the present study was to determine the effect of the application of different rates of fungicide on the metabolism of phenolic compounds in tobacco plants (Nicotiana tabacum L. cv. Tennessee 86). The fungicide applied was carbendazim, with a purity of 100%, at three different rates: 1.3 mM (carb(1)), 2.6 mM (this being the recommended concentration, carb(2)), and 5.2 mM (carb(3)). The control treatment was without carbendazim. The results in relation to control plants indicate that the application of carb(1) in tobacco plants not afflicted by damaging biotic and abiotic agents boosts phenolic accumulation. Therefore, in the case of carbendazim, the application of 50% less (carb(1), 1.3 mM) than the recommended dosage (carb(2), 2.6 mM) of this fungicide could be more effective, because the foliar accumulation of phenolics presented at carb(1) may imply an increased resistance of plants to pathogen infection. On the other hand, we found an inhibition of the phenolic oxidation by the application of carbendazim, principally at carb(3). These results suggest that the excessive application of carbendazim (5.2 mM) could be harmful for healthy plants, because, on inhibiting phenolic metabolism (biosynthesis and oxidation), such treatment would also sharply reduce the capacity of these plants to respond against pathogen attack.
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Bencimidazoles/farmacología , Carbamatos , Fungicidas Industriales/farmacología , Nicotiana/efectos de los fármacos , Nicotiana/metabolismo , Fenoles/metabolismo , Plantas Tóxicas , Bencimidazoles/administración & dosificación , Relación Dosis-Respuesta a DrogaRESUMEN
The mutagenic potential of a crude extract of Parthenium hysterophorus L. was assessed in the Salmonella/microsome (Ames) assay and the mouse bone marrow micronucleus test. Results in the bacterial mutagenicity assay were negative for the five strains employed, e.g. TA 1535, TA1537, TA 98, TA 100 and TA 102, while cytotoxicity was evident in all cases at 5000 microg per plate, the highest concentration assayed. A decrease in toxicity was observed with exogenous mammalian metabolic activation (S9) or glutathione (5 micromol per plate). When mutagenicity was monitored after column chromatography fractionation of the crude, fraction 1 was mutagenic in strain TA 98 (+S9). Besides, cytotoxicity was found in fraction 5, where parthenin was eluted. The micronucleus test was negative in mice upon oral administration, at doses up to 96 mg of crude per kg. Bone marrow toxicity was not observed. The crude extract exhibited some in vitro pro-oxidant activity. It also inhibited lipid peroxidation (IC(50)=4.1 microg/ml) but failed to act as .OH scavenger.
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Plantas Medicinales , Tanacetum parthenium/toxicidad , Animales , Antioxidantes/farmacología , Peroxidación de Lípido/efectos de los fármacos , Ratones , Pruebas de Micronúcleos , Microsomas/efectos de los fármacos , Pruebas de Mutagenicidad , Fitoterapia , Extractos Vegetales/administración & dosificación , Extractos Vegetales/toxicidad , Plantas Medicinales/toxicidad , Salmonella/efectos de los fármacos , Tanacetum parthenium/uso terapéuticoRESUMEN
The reducing activity on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, z.rad;OH radical scavenging potential, in vitro inhibition of lipid peroxidation and modulation of mutagenicity induced by ter-butyl hydroperoxide (TBH) in Escherichia coli were sequentially screened in 45 species of plants used with medicinal purposes in Cuba, in a search for antioxidant agents which protect DNA against oxidative stress.Five species, e.g. Tamarindus indica L., Lippia alba L., Pimenta dioica (L.) Merr, Rheedia aristata Griseb. and Curcuma longa L. displayed IC(50)<30 micro g/ml in the DPPH radical reduction assay and IC(50)<32 micro g/ml in lipid peroxidation inhibition testing. Pimenta dioica and Curcuma longa L. showed also a 20% inhibition of the in vitro induced z.rad;OH attack to deoxyglucose. Further antimutagenesis assay in Escherichia coli IC 188 evidenced that only Pimenta dioica prevents DNA damage by TBH to the test bacteria. A role of antioxidant enzymes is presumed in this case, as judged by a different response in the isogenic Escherichia coli IC 203 deficient in catalase and alkyl hydroperoxide reductase and the discrete inhibition of oxidative mutagenesis also observed when pre-treatment of the extract was assayed. Eugenol, the main constituent of the essential oil of Pimenta dioica, also inhibited oxidative mutagenesis by TBH in Escherichia coli, at concentrations ranging from 150 to 400 micro g/plate.
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Antimutagênicos/farmacología , Antioxidantes/farmacología , Plantas Medicinales/química , Compuestos de Bifenilo , Cuba , Daño del ADN , Escherichia coli/efectos de los fármacos , Escherichia coli/metabolismo , Depuradores de Radicales Libres/farmacología , Radicales Libres/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Medicina Tradicional , Picratos/farmacología , Extractos Vegetales/farmacología , Estructuras de las Plantas/químicaRESUMEN
Twenty-nine dairy farms were selected to determine the incidence of clinical mastitis, prevalence of sub-clinical mastitis and bacterial aetiology in the West Littoral Region of Uruguay. In samples taken by the owner and frozen at -20 degrees C during a week the incidence rate of clinical mastitis was determined as 1.2 cases per 100 cow-months at risk. Staphylococcus aureus was the most common isolated pathogen in 37.5% of 40 milk samples from clinical cases obtained in 1 month. No bacteria grew in the 32.5% of the total samples. A sub-sample including 1077 dairy cows from randomly selected farms was used to determine the prevalence of sub-clinical mastitis. These samples were taken on one visit to each farm. The prevalence was 52.4% on a cow basis and 26.7% on an udder quarter basis. In 55.1% of the quarters of the selected animals with more than 300,000 cells/ml there was no growth. The isolated pathogens from sub-clinical cases and their relative frequencies were: Staphylococcus aureus 62.8%, Streptococcus agalactiae 11.3%, Enterococcus sp. 8%, coagulase-negative staphylococci 7.4%, Streptococus uberis 6.4%, Streptococcus dysgalactiae 1.8%, Escherichia coli 1.5% and Staphylococcus hyicus coagulase-positive 0.6%.
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Mastitis Bovina/epidemiología , Mastitis Bovina/microbiología , Animales , Bovinos , Industria Lechera , Enterococcus/clasificación , Enterococcus/aislamiento & purificación , Escherichia coli/aislamiento & purificación , Femenino , Incidencia , Mastitis Bovina/etiología , Mastitis Bovina/patología , Prevalencia , Índice de Severidad de la Enfermedad , Staphylococcus aureus/aislamiento & purificación , Streptococcus agalactiae/aislamiento & purificación , Uruguay/epidemiologíaRESUMEN
OBJECTIVES: To evaluate the hematological and clinical response to partial splenectomy in a group of children with hereditary spherocytosis. MATERIAL AND METHODS: We analyzed the main hematological and clinical features in 13 patients with hereditary spherocytosis submitted to partial splenectomy. The diagnosis of the disease and the hematological studies was made according to standard methods. To establish the inheritance pattern we also studied both parents. During the surgical procedure the upper two thirds of the spleen were removed and the lower pole was preserved. We use prophylactic penicillin (250 mg twice a day) during 3 years. RESULTS: The diagnosis of the disease was made during the first year of life in 11 patients, 76.9% had neonatal hyperbilirrubinemia, 53.8% showed hepatomegaly and in 69.2% we observed splenomegaly. 84.6% received blood transfusion. The hemoglobin level was significantly increased (p = 0.04) and the reticulocytes significantly diminished (p = 0.01) after splenectomy. No hemolytic crises, blood cell transfusion requirement neither infection was observed after surgery. CONCLUSIONS: Although the number of patients and the post-surgical follow-up is reduced, the hematological recovery observed in our cases suggest that partial splenectomy is a beneficial surgical procedure for the treatment of the typical and severe form of hereditary spherocytosis.
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Esferocitosis Hereditaria/cirugía , Esplenectomía/métodos , Adolescente , Niño , Preescolar , Femenino , Humanos , MasculinoRESUMEN
OBJECTIVE: To analyze the etiology, clinical picture, diagnostic methods, surgical treatment and follow up of a series of six patients with large abdominal pseudocyst as a complication of ventriculo-peritoneal shunts for cerebrospinal fluid relief. DESIGN: Study of a series of cases. PATIENTS AND METHODS: We studied six patients from 1992 to 1995 with large abdominal pseudocyst; there were four women and two men, with range of age from nine to 19 years, and average of 15.9 years. Diagnosis was supported by clinical findings, ultrasound and computed tomographic scan. RESULTS: Meningeal tuberculosis was the cause of hydrocephalus, in five cases and neurocysticercosis in one. The most common symptoms were diffuse abdominal pain, nausea and vomiting. All of them presented with abdominal distention and a soft mass filled with liquid that occupied most of the abdominal cavity without evidence of shunt malfunction. All patients underwent surgical treatment for excision of the pseudocyst and relocation of the catheter of the shunt, without morbidity on mortality. In the follow up we have not experienced recurrence of the pseudocyst in any case. CONCLUSION: According to our experience, we propose that in a patient with a history of meningeal tuberculosis and ventriculo-peritoneal shunt that presents with an abdominal mass should be investigated for the occurrence of a pseudocyst. The ultrasound and tomographic scan are of great value for diagnosis. Surgical treatment through an open laparotomy is the best option for these patients. Morbidity and mortality are considered low, without evidence of recurrence.
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Abdomen , Quistes/etiología , Derivación Ventriculoperitoneal/efectos adversos , Dolor Abdominal/diagnóstico , Dolor Abdominal/etiología , Adolescente , Adulto , Niño , Quistes/cirugía , Femenino , Estudios de Seguimiento , Humanos , Hidrocefalia/etiología , Masculino , Persona de Mediana Edad , Neurocisticercosis/complicaciones , Radiografía Abdominal , Factores de Tiempo , Tomografía Computarizada por Rayos X , Tuberculosis Meníngea/complicacionesRESUMEN
OBJECTIVE: To analyze the role that sympathetic nervous system hyperactivity immediately following brain death plays in the cardiovascular dysfunction of an organ donor. MATERIAL AND METHOD: Fifteen New Zealand white rabbits were placed in three groups: a control group, a brain-death group without propranolol and a brain-death group with propranolol. Brain death was caused by severe intracranial hypertension; in the third group propranolol was first perfused intravenously. We recorded hemodynamic (heart rate, number of extrasystoles, central venous pressure, systemic and pulmonary arterial pressure), biochemical (adrenaline, noradrenaline, dopamine and troponin T) and histologic data. RESULTS: Catecholamine levels rose significantly in both experimental groups after brain death, which coincided with clinical signs of sympathetic hyperactivity in the group not receiving propranolol but not in the group receiving the beta-blocker. The myocardium of animals not receiving the beta-blocker showed myocytolysis, edema, subendocardial bleeding and leukocyte infiltration. Such changes were practically absent in the animals that received beta-blockers. In the beta-blocker group, serum troponin, and index of myocytolysis, rose significantly less than in the non-premedicated group. Blood pressure in all the brain-dead animals was significantly lower than in the control group, but was more severe in animals that had not received propranolol. CONCLUSIONS: Sympathetic nervous system hyperactivity after brain death affects the histology and functioning of the myocardium in this experimental organ donor model. Pretreatment with propranolol prevents damage.
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Antagonistas Adrenérgicos beta/farmacología , Muerte Encefálica/fisiopatología , Hemodinámica/efectos de los fármacos , Hipotensión/prevención & control , Hipertensión Intracraneal/fisiopatología , Isquemia Miocárdica/prevención & control , Miocardio/patología , Propranolol/farmacología , Reflejo Anormal , Sistema Nervioso Simpático/fisiopatología , Antagonistas Adrenérgicos beta/uso terapéutico , Animales , Biomarcadores , Catecolaminas/sangre , Cateterismo , Craneotomía , Hipotensión/etiología , Hipotensión/fisiopatología , Hipertensión Intracraneal/complicaciones , Cambios Post Mortem , Propranolol/uso terapéutico , Conejos , Sistema Nervioso Simpático/efectos de los fármacos , Factores de Tiempo , Obtención de Tejidos y Órganos , Troponina I/sangreRESUMEN
OBJECTIVE: To create an experimental organ donor model and validate it by ultrasound evaluation of intracranial blood flow velocity. MATERIAL AND METHOD: Ten white New Zealand rabbits were assigned to either a control group or an experimental group. Brain death was induced in the experimental group by way of severe cranial hypertension. A diagnosis of brain death was based on physical examination and velocity of intracranial blood flow determined by transcranial doppler ultrasonography. Physical and ultrasound examinations were performed on all animals at baseline and at the time of the experiment. RESULTS: Physical examination and intracranial blood flow velocity were normal in the control group animals at baseline and during the study. The findings were also normal for the experimental group animals at baseline. After provocation of intracranial hypertension, we observed signs of brain death (absence of response to pain stimulus in one cranial par absence of brainstem reflexes, and apnea) in the experimental animals, and the velocity of flow in arteries at the base of the skull acquired the waveform known as sharp systolic peaks, which are characteristic of cerebral circulation failure. CONCLUSIONS: The results of physical examination and ultrasonography in this study provide adequate validation of this experimental model of brain death and demonstrate that transcranial doppler ultrasonography is useful for diagnosing brain death in the rabbit.