The significance of gut sucrase activity for osmoregulation in the pea aphid, Acyrthosiphon pisum.

The osmotic pressure of the body fluids of aphids is lower than in their diet of plant phloem sap. It is hypothesised that aphids reduce the osmotic pressure of ingested food by sucrase-mediated hydrolysis of dietary sucrose to glucose and fructose, and the polymerisation of glucose into oligosaccharides of low osmotic pressure per hexose unit. To test this hypothesis, the impact of the alpha-glucosidase inhibitor acarbose on the sugar relations and osmoregulation of aphids was explored. Acarbose inhibited sucrase activity in gut homogenates and the production of monosaccharides and oligosaccharides in the honeydew of live aphids. Acarbose caused an increase in the haemolymph osmotic pressure for aphids reared on a diet (containing 0.75 M sucrose) hyperosmotic to the haemolymph and not on the isoosmotic diet containing 0.2 M sucrose. It did not affect aphid feeding rate over 2 days, except at high concentrations on 0.75 M sucrose diet, and this may have been a secondary consequence of osmotic dysfunction. Acarbose-treated aphids died prematurely. With 5 microM dietary acarbose, mean survivorship on 0.2 M sucrose diet was 4.2 days, not significantly different from starved aphids, indicating that, although these aphids fed, they were deprived of utilisable carbon; and on 0.75 M sucrose diet, mean survivorship was just 2.8 days, probably as a consequence of osmotic failure. It is concluded that the aphid gut sucrase activity is essential for osmoregulation of aphids ingesting food hyperosmotic to their body fluids.

Acarbosa y propofol: ¿una peligrosa combinación? / Acarbose and propofol: A dangerous combination?

La hepatotoxicidad es una complicación infrecuente tras el empleo de propofol, que puede ser potencialmente grave en caso de no realizarse un diagnóstico precoz. El propofol es un fármaco cada vez más empleado en la práctica diaria no solo en cirugía sino también en la sedación de procedimientos invasivos ambulatorios tales como la endoscopia. Acarbosa es un fármaco clásico en el tratamiento de la diabetes tipo 2 en estadios iniciales que puede causar de forma infrecuente hepatitis tóxica. Se presenta el caso de una paciente que sufrió una hepatitis aguda secundaria al empleo de propofol como anestesia oftalmológica, hepatitis probablemente potenciada por el uso previo de acarbosa. El cuadro se diagnosticó de forma precoz y se resolvió sin complicaciones. El conocimiento de esta complicación en el ámbito de la anestesiología se revela cada vez más importante para mejorar la valoración preanestésica de los pacientes que vayan a ser sedados con propofol y así evitar en lo posible su aparición (AU)

Hepatotoxicity is a rare complication following the use of propofol and can be potentially serious if an early diagnosis is not made. Propofol is being increasingly used in daily practice, not only in surgery, but also in outpatient sedation procedures, such as endoscopy. Acarbose is a well-known drug used in type 2 diabetes treatment, particularly in the early phase. A case is reported on a patient who suffered an acute hepatitis secondary to the use of propofol in ophthalmology surgery, a hepatitis probably enhanced by prior use of acarbose, a drug that also can cause hepatotoxicity. An early diagnosis and it was resolved without complications. This case could contribute to improve pre-anesthetic evaluation of patients who will be undergoing sedation with propofol in order to avoid the possible appearance of hepatitis (AU)