Prueba de concepto de la eficacia del equipo prototipo “Ciclador Automático para Resucitador” en un cerdo adulto

En este estudio se evaluó en una prueba de concepto, la seguridad y funcionalidad del equipo prototipo Ciclador Automático para Resucitador (CAR) en un cerdo de peso similar al de un humano adulto. Para ello, se estudiaron los volúmenes corrientes de 5.8, 7 y 9.7 ml/kg para las presiones positivas al final de la expiración (PEEP) de 5, 10 y 15 cmH2O. Los parámetros indicativos del estado homeostático del animal se obtuvieron a través de un equipo multiparamétrico y un sistema de análisis bioquímicos de sangre EPOC®. En los periodos en los que se evaluaron los volúmenes corrientes de 7 y 9.7 ml/kg los parámetros se mantuvieron dentro de rangos fisiológicos normales. Sin embargo, el volumen corriente de 5.8 ml/kg no fue suficiente para mantener una ventilación adecuada lo que se manifestó a través de hipercapnia y caída del pH. Como conclusión general se puede inferir que con adaptaciones en los patrones de ventilación (7 y 9.7 ml/kg), la utilización del prototipo CAR permitió mantener al animal con vida durante 24 h conservando su homeostasis.

Eficacia de la combinación de Abamectina-Derquantel y de la Moxidectina en cabras lecheras naturalmente parasitadas con nematodos gastrointestinales en el Valle de Lerma, Argentina

El impacto productivo de los nematodos gastrointestinales (NGI) sobre los de pequeños rumiantes es conocido a nivel mundial. Las infestaciones por NGI constituyen una limitante de alto impacto en la producción de rumiantes y las perdidas comprendidas por este problema sanitario varían desde reducciones subclínicas en la ganancia de peso hasta la muerte de animales con altas cargas parasitarias. El objetivo de este trabajo es presentar los resultados de un test de eficacia a campo utilizando una combinación comercial de Abamectina + Derquantel y del Moxidectin en cabras lecheras naturalmente infestadas con NGI en el Valle de Lerma, provincia de Salta. El ensayo se llevó a cabo en la Unidad Tambo Caprino de la Estación Experimental Agropecuaria Salta del INTA. Para la evaluación de eficacia de la droga en estudio, se realizó el test de reducción de conteos de huevos. En los coprocultivos pre-tratamientos se pudo observar una gran prevalencia de Trichostrongylus spp. (71%). seguido de Teladorsagia spp. (21%) y Haemonchus spp. (8%). En cuanto a los resultados del TRCH, en el GDQ se observaron valores del 100% de PRCH, mientras que en el GMX se observó un PRCH de 95,5 %, donde la eficacia para Haemonchus spp. y Teladorsagia spp. fue del 100% y para Trichostrongylus spp. del 81,1%.Los resultados observados en este trabajo permiten concluir que en las condiciones de campo en donde fue llevado a cabo el TRCH, la combinación Derquantel-Abamectina posee una alta eficacia contra los géneros presentes

COMPARACIÓN ENTRE EL MODELO PROBIT Y EL MODELO DE HILL PARA DETERMINAR LA EFICACIA DE IVERMECTINA SOBRE LARVAS DE Rhipicephalus (Boophilus) microplus (ACARI, IXODIDA: IXODIDAE) MEDIANTE LA TÉCNICA DE INMERSIÓN.

The aim of this study was to propose an alternative statistic treatment for the results obtained by testing the in vitro efficacy of ivermectin (IVM) against R. microplus using the larval immersion test in order to detect the emergence of resistant strains. The statistical analysis of the results obtained by this technique is standardized by the FAO who proposes the use of the Probit model. However there are alternative mathematical models that allow a more precise analysis of experimental data generating more information as nonlinear logistic equation, also called the Hill model. The results of the IVM efficacy against a sensible strain of R. microplus were analysed whit both model. A comparison between the results obtained with PROBIT and Hill model showed that the last one was able to make a more precise fit of the experimental data, generating more information about small IVM concentrations. The C50 (13.58 ppm) obtained with Probit model result smaller than the obtained with the Hill model (14.24 ppm), however the C90, C99 and the discriminant dose (19.31 ppm, 25.74 ppm, 51.48 ppm) obtained with de Hill model were bigger than the obtained with the Probit model (17.50 ppm, 21.98 ppm, 43.96 ppm).

ESTIMACIÓN DE UNA DOSIS DE MARBOFLOXACINA PARA CABRAS DE TRES SEMANAS DE EDAD MEDIANTE ANÁLISIS POBLACIONAL

A dose of marbofloxacin (MFX) to treat gastrointestinal infections caused by E. coli in 3-week-old goats was estimated. The pharmacodynamics of MFX against E. coli was evaluated in vitro by estimation of minimum inhibitory concentration (MIC), minimum bactericide concentration (MBC) and mutant prevention concentration (MPC). Marbofloxacin was administered to six 3-week-old goats by subcutaneous route at the dose of 2 mg/kg. The pharmacokinetic parameters were estimated by non-compartmental analysis. The dose of MFX capable to protect the 95% of population was calculated considering the population distribution of pharmacokinetic parameters. The efficacy of MFX was evaluated by the relationship between the area under curve and MPC (AUC/MPC) with a cut-off value of 22 h. The results showed that the estimated dose of MFX to reach the clinical outcome of gastrointestinal infections caused by E. coli and to prevent the bacterial resistance at the 95% of the population of 3-week-old goats was 3,179 mg/kg, which for practical reasons was fixed at 3,5 mg/kg. The in vivo efficacy of dose estimated will be tested in future studies.

SENSIBILIDAD DE LA GARRAPATA COMÚN DEL BOVINO Rhipicephalus (Boophilus) microplus A IVERMECTINA ESTIMADA CON EL MODELO SIGMOIDEO DE RESPUESTA MÁXIMA O DE HILL

The aim of this study was to obtain pharmacodynamics parameters to detect resistance or susceptibility of R. microplus strains to ivermectin (IVM). Two larvae samples; a susceptible strain (S) and field isolation (T) were treated with increasing concentrations of IVM using the larvae immersion technique the efficacy values measured at 24 hours were analysed with the sigmoidal maximum response so called Hill model as statistical analysis. The results obtained showed that the IVM have an all or nothing response represented by the Hill coefficient value >1 in both samples. Additionally, a low concentration effect was observed as E0 de 12.83% (S) and 9.91% (T). The field isolation larvae were susceptible to IVM in comparison with the susceptible strain by the resistance ratio (RR) which in one case was not significantly greater that one (RR50= 0.756 and RR90=1.009).

PRIMER REPORTE DE LESIONES PARASITARIAS COMPATIBLES CON Oslerus osleri (COBBOLD, 1876) EN AGUARÁ GUAZÚ, Chrysocyon brachyurus (ILLIGER, 1811) DE LA PROVINCIA DE SANTA FE.

The necropsy of 5 specimens of C. brachyurus which were accidentally run over on different routes in the north-central province of Santa Fe. All of these had multiple whitish nodules with a cystic appearance between the distal third of the trachea and bronchi containing parasites arranged in the shape of a ball inside. Morphological identification of adult’s nematodes and larvae eggs from females was performed, where it was possible to identify typical characters of the species O. osleris. Likewise, the lungs were increased in consistency, with petechial and multifocal ecchymosis and the presence of whitish nodules scattered throughout the parenchyma. Two of the canids had an increase in the size of the bronchial lymph nodes. The inspection of the respiratory system together with the observation of lesions and the nematodes found inside with their corresponding measurements, are compatible with the species O. osleri, which would imply the first report of this parasite in wild canids from Argentina.

DILUCIÓN DE MIEL EN AGUA INDUCE HORMESIS EN LA ACTIVIDAD ANTIBACTERIANA SOBRE Staphylococcus aureus.

In pharmacology, hormesis is defined as the high efficacy of a drug at low doses and a decrease of efficacy at higher doses. In this study, the hormesis phenomenon on the antibacterial activity of honey was assessed. The activity of four honeys (A, D, C and D) were checked by agar plate diffusion method using S. aureus (ATCC 29213) as the test organism. Each honey was tested as follows; on the surface of an agar plate, five stainless steel cylinders with a diameter of 8,14 mm were radially disposed. Onto each cylinder 0,1 mL of the sample honey diluted in water at 50 – 25 - 12,5 -6,25 and 3,125 % v/v were placed. Plates were incubated at 35°C during 24 h. The surface of the cylinder diameter was set as reference antibacterial activity (Ra). The antibacterial activity of each honey was quantitated by the relationship between the surface of the inhibitory zone (Iz) and the surface of the reference activity (Iz/Ra). An increase in the antibacterial activity was observed at a concentration of water greater than 50% in honeys B and C. This hormetic behavior could be considered as indicator of the quality of the antibacterial activity of these honeys.

OPTIMIZACIÓN DE LA PRODUCCIÓN DE BIOMASAS DE Kluyveromyces marxianus EN LACTOSUERO

Whey is a by-product of cheese making and represents a danger of environmental contamination when discarded without prior treatment. However, due to its high content of lactose, vitamins and proteins, whey should not be considered a waste, but rather a raw material for obtaining value-added products. Among the alternatives for its use, biomass production stands out through fermentation with Kluyveromyces marxianus. Therefore, this work determines the best operating conditions for biomass production, minimizing residual lactose. To this end, a Doehlert Experimental Matrix Design was used to optimize the effects of aeration and nitrogen source concentration on the growth of K. marxianus by a minimum number of experiments. The results obtained allow maximizing the biomass production, the consumption of lactose and protein by K. marxianus, thus achieving a more effective treatment of whey prior to its discard.

APLICACIÓN DE COLORACIONES ESPECIALES EN EL DIAGNÓSTICO HISTOPATOLÓGICO: TINCIÓN TRICRÓMICA DE MASSON

Masson's trichrome (MT) is a three-color staining protocol used in histology. MT allows to show and quantify changes such as tissue repair (healing) and collagen deposition. Also, it can be used to quantify blood vessels, in epithelial dysplasia and squamous cell carcinoma. The objective of this work is to describe the MT staining technique and to exemplify some applications of this technique in routine veterinary histopathological diagnosis. Archived histologic sections were selected from the records of the histopathology laboratory. Tissues were selected in base on theirs structures and lesions that could be evaluated with MT: a rabbit lung with a chronic suppurative bronchopneumonia; a bovine liver with lesions of Echium plantagineum poisoning; and a bovine eyelid with a squamous cell carcinoma. The TM was able to show fibroplasia in the pulmonary interstitium and confirm the presence of a chronic respiratory process, and clearly revealed an abundant fibrovascular tumor stroma, with profuse connective tissue and neovascularization between the tumor cells in deep dermis. In the liver, extensive and marked fibroplasia was confirmed. MT represents a complementary coloration to routine hematoxylin and eosin stain (H&E) and provides accurate information from several pathological processes, mainly those related to fibrovascular proliferation and scarring.

DETERMINACIÓN DE LA CONCENTRACIÓN EFECTIVA 50, 90 Y 99 DE IVERMECTINA SOBRE UNA CEPA DE GARRAPATA COMÚN DEL BOVINO (Rhipicephalus (Boophilus) microplus) PROVENIENTE DE LA PROVINCIA DE SANTA FE-ARGENTINA

The aim of this study was to obtain the sensitivity data of the native strains of R. microplus to ivermectin (IVM) in the province of Santa Fe-Argentina, in order to detect the emergence of resistant strains. Native (field isolation) and susceptible (reference) larvae of R. microplus were treated with increasing concentrations of IVM in order to determine its efficacy at different doses. The statistical treatment of the concentration-efficacy curves was performed by the PROBIT model, who is a standardized method proposed by FAO. The results obtained indicated that the larvae isolated were susceptible, being the values of LD50 (9.66 ppm) and LD90 (17.41 ppm), which were lower than those of the reference strain (LD50:13.58 ppm, LD90:19.31 ppm), and the RR (resistance ratio) were less than one (RR50: 0.711; RR90: 0.901). The DL99 (51.48 ppm) was only obtained in the reference strain to determine the discriminant dose (DL99x2), which is a parameter that could be used to easily discriminate susceptible and resistant larvae populations.