Intracellular nicotinamide adenine dinucleotide promotes TNF-induced necroptosis in a sirtuin-dependent manner.

Cellular necrosis has long been regarded as an incidental and uncontrolled form of cell death. However, a regulated form of cell death termed necroptosis has been identified recently. Necroptosis can be induced by extracellular cytokines, pathogens and several pharmacological compounds, which share the property of triggering the formation of a RIPK3-containing molecular complex supporting cell death. Of interest, most ligands known to induce necroptosis (including notably TNF and FASL) can also promote apoptosis, and the mechanisms regulating the decision of cells to commit to one form of cell death or the other are still poorly defined. We demonstrate herein that intracellular nicotinamide adenine dinucleotide (NAD(+)) has an important role in supporting cell progression to necroptosis. Using a panel of pharmacological and genetic approaches, we show that intracellular NAD(+) promotes necroptosis of the L929 cell line in response to TNF. Use of a pan-sirtuin inhibitor and shRNA-mediated protein knockdown led us to uncover a role for the NAD(+)-dependent family of sirtuins, and in particular for SIRT2 and SIRT5, in the regulation of the necroptotic cell death program. Thus, and in contrast to a generally held view, intracellular NAD(+) does not represent a universal pro-survival factor, but rather acts as a key metabolite regulating the choice of cell demise in response to both intrinsic and extrinsic factors.

Animal trypanosomosis: making quality control of trypanocidal drugs possible.

African animal trypanosomosis is arguably the most important animal disease impairing livestock agricultural development in sub-Saharan Africa. In addition to vector control, the use oftrypanocidal drugs is important in controlling the impact of the disease on animal health and production in most sub-Saharan countries. However, there are no internationally agreed standards (pharmacopoeia-type monographs or documented product specifications) for the quality control of these compounds. This means that it is impossible to establish independent quality control and quality assurance standards for these agents. An international alliance between the Food and Agriculture Organization of the United Nations, the International Federation for Animal Health, the Global Alliance for Livestock Veterinary Medicines, the University of Strathclyde and the International Atomic Energy Agency (with critical support from the World Organisation for Animal Health) was established to develop quality control and quality assurance standards for trypanocidal drugs, with the aim of transferring these methodologies to two control laboratories in sub-Saharan Africa that will serve as reference institutions for their respective regions. The work of the international alliance will allow development of control measures against sub-standard or counterfeit trypanocidal drugs for treatment of trypanosome infection. Monographs on diminazene aceturate (synonym: diminazene diaceturate), isometamidium chloride hydrochloride, homidium chloride and bromide salts and their relevant veterinary formulations for these agents are given in the annex to this paper. However, the authors do not recommend use of homidium bromide and chloride, because of their proven mutagenic properties in some animal test models and their suspected carcinogenic properties.

Use of cymelarsan in goats chronically infected with Trypanosoma evansi.

Toxicity and therapeutic trials using Cymelarsan (an arsenical compound) against Trypanosoma evansi infection were carried out using chronically infected goats. For the toxicity trial, 40 goats were divided into four groups of 10 animals each; the first three groups received s.c. injections of 5, 10, and 15 mg/kg bw of Cymelarsan, respectively, and the last one served as control. No systemic reaction was observed in any goat throughout the experiment. For the therapeutic trial, 15 adult female goats were inoculated intravenously with at least 1 x 10(5)T. evansi isolated in the Canary Islands. Six months after inoculation, the animals were treated with Cymelarsan at single dose of 0.3 mg/kg (5 animals), 0.5 mg/kg (5 animals), and 0.625 mg/kg (5 animals). At 4 and 6 weeks after treatment, two goats belonging to 0.3 mg/kg group showed recurrence of trypanosomes. Parasitemia, however, was negative in all animals belonging to 0.5 and 0.625 mg/kg groups until the end of the experiment (6 months after treatment). Thus, it can be concluded that Cymelarsan is a safe trypanocidal drug for goats and that the curative dose is 0.5 mg/kg or above.

Pharmacokinetics of ketoprofen in the donkey (Equus asinus).

The pharmacokinetic parameters of ketoprofen were determined in four donkeys after a single intravenous injection of a dose of 2.2 mg/kg body weight. The total body clearance (ClB) was 414.0 +/- 98.70 ml/h/kg (mean +/- SD), the volume of distribution at steady state (Vss) 263.10 +/- 55.43 ml/kg and the elimination half-life 1.30 +/- 0.75 h. These values were compared to those obtained in horses.

Evaluation of nitroxynil and closantel activity using ELISA and egg counts against Fasciola hepatica in experimentally and naturally infected cattle.

The responses of cattle infected with Fasciola hepatica to treatment with nitroxynil or closantel were monitored by faecal egg counts and by ELISA assay of anti-fluke antibodies. A first trial with experimentally infected heifers showed an increase in anti-fluke antibody titre as early as 2 weeks post-infection. Eggs were first detected in the faeces 10 weeks after infection. Egg output increased steadily over the next 8 weeks and then rapidly decreased. Treatment of a 20-week infection with nitroxynil was followed by a slow decrease in antibody titre 4 weeks later. This decrease continued over the next 40 weeks, but returned to pre-infection levels in only 2 out of 4 animals. The faecal egg count fell to zero 2 weeks after treatment and remained so for the following 30 weeks, although 1 animal produced a few eggs 32 and 34 weeks post-treatment. Within this period, neither diagnostic technique discriminated between this persistently infected animal and the others. In a second trial, 45 cattle from a naturally infected herd were treated with nitroxynil or closantel. The faecal egg counts of the treated cattle were zero within the following 2 months, whereas there were eggs in the faeces of the control (untreated) group. Nevertheless, the treated cattle showed a small, non-significant drop in anti-fluke antibody titre. These results demonstrate the need for new tools to monitor and evaluate accurately the efficacy of anthelmintic treatment.

[Doxycycline: pharmacokinetics and suggested dosage in dogs and cats]. / Doxycycline: farmacokinetiek en doseringsvoorstellen bij hond en kat.

Data on the pharmacokinetics of doxycycline in dogs and cats are reported. Doxycycline was given orally in the form of palatable tablets of Ronaxan. Tablets of 100 mg of doxycycline (as hyclate) were used in dogs, whereas cats were given tablets of 20 mg. The doses administered were 10 mg/kg in both species. The pharmacokinetics of doxycycline in dogs and cats were compared with those obtained in man (at a dosage of 3 mg/kg/day). It is concluded that a dosage of 10 mg/kg/day of doxycycline is required to obtain effective plasma concentrations in dogs and cats for 24 hours, when this dose is administered once daily.