High frequency of larval abnormalities of the toad Rhinella arenarum (Anura: Bufonidae) in an Argentinian agroecosystem

Introduction: The frequent use of pesticides is currently considered a cause of environmental pollution due to the high rate of entry of these substances into agroecosystems. This constitutes a risk for the species that inhabit these ecosystems, in particular anurans whose characteristics make them prone to exposure to and interaction with environmental pollutants. Objective: To report the occurrence of abnormalities in larvae of the common toad Rhinella arenarum inhabiting ponds surrounded by agroecosystems. Methods: In two consecutive springs (2015 and 2016), reproductive events of common toads were monitored in temporary pond systems in agricultural and non-agricultural areas, located near the city of La Plata (Buenos Aires, Argentina). The physicochemical parameters of the ponds were measured, and the stage of each reproductive event was recorded, such as the numbers of adult toads, amplexus and clutches. In the laboratory, the larvae were measured and photographed, their stage of development was recorded, and their morphology was examined under a stereomicroscope. Representative samples (normal and abnormal) from each pond studied were processed for histopathological analysis. Results: In the field studies carried out on a population of R. arenarum collected in an agroecosystem, a lower number of reproductive adults and clutches were observed in relation to the population of a non-agricultural pond. A total of 1 910 larvae were collected: 529 and 1 381 larvae from ponds located in non-agricultural and agricultural areas, respectively. Larvae from the agroecosystem showed two types of abnormalities: severe tail flexure and abdominal bloating. In addition, five degrees of severity could be determined in relation to abdominal bloating. Conclusions: This work reports the high frequency and severity of abnormalities observed in the early stages of R. arenarum larvae living within an agroecosystem, providing evidence of the negative impact that agricultural activities cause on aquatic ecosystems surrounded by farming areas.

Introducción: El uso frecuente de plaguicidas es considerado actualmente una causa de contaminación ambiental debido a las altas tasas de ingreso de estas sustancias a los agroecosistemas. Esta situación es un riesgo para las especies que habitan en estos ecosistemas, en particular los anuros cuyas características los hacen propensos a la exposición e interacción con contaminantes ambientales. Objetivo: Informar la presencia de anormalidades en larvas del sapo común Rhinella arenarum que habitan en estanques rodeados por un agroecosistema. Métodos: En dos primaveras consecutivas (2015 y 2016), se monitorearon los eventos reproductivos del sapo común proveniente de sistemas de estanques temporales ubicados en zonas agrícolas y no agrícolas, cerca de la ciudad de La Plata (Buenos Aires, Argentina). Se midieron los parámetros fisicoquímicos de los estanques y se registraron las etapas de cada evento reproductivo como el número de sapos adultos, amplexos y nidadas. En el laboratorio, las larvas fueron medidas y fotografiadas, se registró su estado de desarrollo y se examinó la morfología de cada una bajo microscopio estereoscópico. Se procesaron muestras representativas (normales y anormales) de cada estanque estudiado para análisis histopatológico. Resultados: En la población de R. arenarum que vive dentro de un agroecosistema, se observó un menor número de adultos reproductores y puestas en relación con la del estanque en la zona no agrícola. Se recolectaron un total de 1 910 larvas: 529 y 1 381 larvas de estanques ubicados en zonas no agrícolas y agrícolas, respectivamente. Las larvas del agroecosistema mostraron dos tipos de anormalidades: severa flexión de la cola y distensión abdominal. Además, se pudo determinar cinco grados de gravedad en relación con la distensión abdominal. Conclusiones: Una alta frecuencia y severidad de anormalidades en los estadios tempranos de larvas de R. arenarum que viven dentro de un agroecosistema proporciona evidencia del impacto negativo que las actividades agrícolas causan en los ecosistemas acuáticos rodeados por áreas de cultivo.

In Vivo Evaluation Of Tazarotene Solid Lipid Nanoparticles Gel For Topical Delivery

The purpose of this research work was to develop and optimize the Solid Lipid Nanoparticles (SLNs) of Tazarotene for the effective topical delivery in the treatment of psoriasis. Tazarotene loaded SLNs were prepared by hot homogenization followed by the ultrasonication using Taguchi’s design and based on the results further investigation was made using central composite design. The lipid Dynasan-116, surfactant poloxomer-188 and co surfactant egg lecithin resulted in better percent drug loading and evaluated for particle size, zeta potential, TEM, drug entrapment efficiency, in vitro drug release and stability. All parameters were found to be in an acceptable range. In vitro drug release of optimized SLN formulation (F1) was found to be 98.12 ± 1.52%, whereas pure drug release was 42.12 after 60 min. The optimized formulation was incorporated into the gel. The release rate (flux) of tazarotene across the membrane and excised skin differs significantly. The accumulative amount of Tazarotene in skin from SLN based gel formulation and marketed gel were 41.12 ± 0.12 mg and 30.02 ± 0.04 mg respectively. This result supported our hypothesis made in skin permeation studies on rat skin. From histopathological studies the microscopic observations indicate that the optimized SLN formulation, SLN based gel formulation and marketed gel has no significant effect on the microscopic structure of the skin. The skin-irritation studies indicated that SLN based gel containing Tazarotene did not show any sign of skin irritation as compared to moderate erythema shown by marketed gel formulation (Tazret® gel) after 72 h of application. Thus, SLN based gel formulation demonstrated advantage over marketed formulation in improving the skin tolerability of Tazarotene indicating their potential in improving patient acceptance and topical delivery of Tazarotene.

Protective Properties of Citrullus lanatus on Carbon Tetrachloride Induced Liver Damage in Rats.

Aim: This study was conducted to investigate the effects of the leaf extract of Citrullus lanatus on carbon tetrachloride (CCl4) induced liver damage in rats. Methodology: Hepatoprotective study was conducted using five groups (A-E) of six male rats per group. Groups A and B served as the control groups and were respectively administered with distilled water and CCl4 in olive oil while groups C, D and E were administered respectively with 500, 1,000 and 1,500mg/kg body weight of the ethanolic leaf extract of C. lanatus for 7 days. Animals were subsequently anaesthetized, blood samples were collected for alanine amino transferase (ALT), aspartate amino transferase (AST), alkaline phosphatase (ALP), total bilirubin, total protein and albumin assays; liver organ was isolated and processed for biochemical and histopathological studies. Results: There were significant increases (P=0.05) in the serum levels of ALT and AST both in the plasma and liver homogenate in the group treated with CCl4 as compared to negative control group; while in the extract treated group, there was a decrease in the levels of the aminotransferases. Histopathological studies showed severe portal congestion and necrosis of hepatocytes in the group treated with CCl4 while the groups administered with the extract treated group showed a moderate venous congestion with absence of necrosis. Conclusion: These results highlight the ability of the leaf extract of C. lanatus to ameliorate damage in the liver of albino rats.