The Effect of Intercropping Populus 'RAP' with Beans

Dwarf French beans and broad beans were grown at 0.25 m x 0.25m for 2 years with a without cuttings of Populus ‘RAP’at spacings of 2.0 m x 0.5 m and 3.0 m x 0.5 m. The presenceof beans lead to a greater height and diameter growth and greatertotal dry matter production per hectare of the Populus at bothspacings after 2 years. Bean yield was reduced at the end ofthe second year by the presence of Populus; there was no effectat the end of the first year.     

The pharmacokinetics and pharmacodynamics of alfaxalone in cats after single and multiple intravenous administration of Alfaxan® at clinical and supraclinical doses

This study aimed to determine the pharmacokinetic parameters and pharmacodynamics of alfaxalone in a 2‐hydroxypropyl‐β‐cyclodextrin alfaxalone formulation (Alfaxan^®, Jurox Pty Ltd, Rutherford, NSW, Australia) in cats after single administration at clinical and supraclinical dose rates and as multiple maintenance doses. First, a prospective two‐period cross‐over study was conducted at single clinical and supraclinical doses. Second, a single group multiple dose study evaluated the effect of maintenance doses. Eight (five female and three male) domestic cats completed the cross‐over experiment and six female cats completed the multiple dose study. In the first experiment, alfaxalone was administered intravenously (IV) at 5 or 25 mg/kg with a washout period of 14 days. In the second experiment, alfaxalone was administered IV at 5 mg/kg followed by four doses each of 2 mg/kg, administered at onset of responsiveness to a noxious stimulus. Blood was collected at prescribed intervals and analysed by LCMS for plasma alfaxalone concentration. Noncompartmental pharmacokinetics were used to analyse the plasma alfaxalone data. The plasma clearance of alfaxalone at 5 and 25 mg/kg differed statistically at 25.1 and 14.8 mL/kg/min respectively. The elimination half lives were 45.2 and 76.6 min respectively. Alfaxalone has nonlinear pharmacokinetics in the cat. Nevertheless, for cats dosed with sequential maintenance doses, a regression line through their peak plasma concentrations indicated that there was no clinically relevant pharmacokinetic accumulation. The duration of nonresponsiveness after each maintenance dose was similar at approximately 6 min, indicating a lack of accumulation of pharmacodynamic effect. The cardiovascular and respiratory parameters measured in cats after administration of the labelled doses of Alfaxan^® were stable. In conclusion, the pharmacokinetics of alfaxalone in cats are nonlinear. At clinical dose rates, however, neither alfaxalone nor its effects accumulated to a clinically relevant extent. Further, in the un‐premedicated cat the induction and maintenance of surgical anaesthesia was free of untoward events after a dose of 5 mg alfaxalone/kg body weight followed by four sequential doses of 2 mg/kg as needed (i.e., approximately 7 to 8 mg/kg/h).     

Biochemical evidence of hybrid gene introgression in some reservoir populations of tilapia in southern Sri Lanka

Abstract. Two species of tilapia, Oreochromis mossambicus (Peters) and O. niloticus (L.), from five reservoirs in southern Sri Lanka as well as fish from a fish hatchery and laboratory stock were studied by starch gel electrophoresis at 18 enzyme loci, to determine the degree of mixing of the two species. Two reservoirs showed little or no mixing between O. mossambicus and O. niloticus , while two other reservoirs as well as the hatchery stock showed a high degree of mixing of the two species. The laboratory stock of O. niloticus also showed introgression of O. mossambicus alleles. The similarities of the local stocks to the original African as well as other Asian stocks is discussed.