Ciprofloxacin was concentrated within human neutrophils to between four and seven times the extracellular concentration. Uptake was rapid and dependent on temperature, but not pH. The elution of ciprofloxacin from cells was equally rapid when the extracellular concentration was reduced. Intracellular ciprofloxacin was biologically active. It produced a significant reduction in viable counts of intracellular Staphylococcus, aureus in the presence of extracellular concentrations as low as 0.5 mg/l. The prior ingestion of Staph. aureus by neutrophils appeared to have no effect on ciprofloxacin uptake.

In most countries, male pigs are physically castrated soon after birth to reduce the risk of boar taint and to avoid behaviours such as fighting and mounting. However, entire male pigs are more feed efficient and deposit less fat than barrows. In addition, many animal welfare organizations are lobbying for a cessation of castration, with a likelihood that this could lead to inferior pork unless an alternative method is used to control boar taint. An alternative to physical castration is immunization against gonadotrophin releasing factor (GnRF) which allows producers to capitalize on the superior feed efficiency and carcass characteristics of boars without the risk of boar taint. From a physiological perspective, immunized pigs are entire males until shortly after the second dose, typically given 4 to 6 weeks before slaughter. Following full immunization, there is a temporary suppression of testicular function and a hormonal status that resembles that of a barrow. Nutrient requirements will be different in these two phases, before and after full immunization. Given that there have been few published studies comparing the lysine requirements of entire males and barrows in contemporary genotypes, it is useful to use gilt requirements as a benchmark. A series of meta-analyses comparing anti-GnRF immunized boars and physical castrates and use of nutritional models suggest that the lysine requirement of entire males before the second immunization is 5% higher than for gilts, from 25 to 50 kg BW, and by 8% from 50 to 95 kg. Given that the penalty in growth performance for having inadequate dietary lysine is greater in males than in gilts or barrows, it is important to ensure that lysine requirements are met to obtain the maximum benefits of entire male production during this phase. After the second immunization, the lysine requirement of immunized males decreases and may become more like that of barrows. In addition, a consistent effect of full immunization is a marked increase in voluntary feed intake from about 10 days after the second dose. Putting these together, the estimated lysine requirement, expressed in terms of diet composition, falls to 94% of the gilt level. Although general principles can be described now, further research is needed to fully define the lysine requirements of immunized boars. It is important that the temporal pattern of tissue deposition rates and feed intake be explored to be incorporated into models to predict nutrient requirements over the period of rapidly changing metabolism.Keywords: finishing pigs, growth, boars, nutritional requirements, immunological castration. ImplicationsMale pigs immunized against gonadotrophin releasing factor are physiologically entire males for most of their life and as such they should be fed as entire males at least up until the second immunization. Shortly after that time, testicular function is suppressed and the hormonal and metabolic status rapidly adjusts to resemble that of a physical castrate. As a consequence, feed intake and tissue deposition ch...

SUMMARY Ciprofloxacin was concentrated within mouse peritoneal macrophages to between two and three times extracellular values. Uptake was rapid, occurred equally well with dead cells, and was not affected by lowering the pH or by prior ingestion of Staphylococcus aureus. Intracellular staphylococci were killed by extracellular concentrations of ciprofloxacin as low as 0-5 mg/l. Ciprofloxacin(1-cyclopropyl-6fluro-1,

Ciprofloxacin is taken up rapidly by both human neutrophils and mouse peritoneal macrophages. It does not appear to be bound firmly within the cell and can be eluted readily if the extracellular concentration is lowered. Uptake does not depend on an active transport mechanism. Intracellular ciprofloxacin is biologically active reducing the survival of intracellular Staphylococcus aureus and Mycobacterium fortuitum, in vitro. In vivo, ciprofloxacin was effective in treating a murine systemic infection with an intracellular pathogen Salmonella typhimurium. The progress of infection in sensitive mice with no natural immunity was delayed by ciprofloxacin although at the dosage used the mice were not cured. These results suggested that clinical studies in patients infected by intracellular pathogens are warranted and that ciprofloxacin may have an important role in the treatment of this type of infection.

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