Age-related dynamics of constitutive cytokine transcription levels of feline monocytes.

Monocytes/macrophages are central mediators of inflammation and immunity and therefore of major interest in the study of immunosenescence. In healthy adult cats, monocytes have been shown to constitutively transcribe pro- and anti-inflammatory cytokines. However, in order to characterize the effect of age, feline monocyte functions were examined for changes in cytokine transcription levels in early stages of immunosenescence. For this purpose, isolated, short-term cultured monocytes from barrier-maintained adult cats of different ages (15 mo to 10 yr) were examined for transcription of IL-1 beta, IL-6, IL-10, IL-12 p40 and TNF-alpha by real-time PCR. Transcription levels of cytokines varied and were generally highest for IL-1 beta. For IL-1 beta, IL-6 and IL-12 p40, both young and old cats exhibited highest levels. The age association was significant. TNF-alpha appeared to be transcribed at similar levels over the examination period, whereas IL-10 tended to decline with age but without any statistical significant differences. The observed age association of the constitutive transcription of some cytokines indicates a drop in monocyte activities from youth to middle age, which is then followed by a (progressive) increase with increasing age. This provides evidence that monocytes are in part responsible for the pro-inflammatory status observed with ageing.

Radioiodine treatment of feline hyperthyroidism in Germany.

AIM: Establishment of radioiodine treatment of feline hyperthyroidism in veterinary routine in accordance with German radiation protection regulations. PATIENTS AND METHODS: 35 cats with proven hyperthyroidism were treated with 131I in a special ward. Thyroid uptake and effective halflife were determined using gammacamera dosimetry. Patients were released when measured whole body activity was below the limit defined in the German "Strahlenschutzverordnung". RESULTS: 17/20 cats treated with 150 MBq radioiodine and 15/15 cats treated with 250 MBq had normal thyroid function after therapy, normal values for FT3 and FT4 were reached after two and normal TSH levels after three weeks. In 14 cats normal thyroid function was confirmed by controls 3-6 months later. Thyroidal iodine uptake was 24 +/- 10%, effective halflife 2.5 +/- 0.7 days. Whole body activity < 1 MBq was reached 13 +/- 4 days after application of 131I. Radiation exposure of cat owners was estimated as 1.97 microSv/MBq for adults. CONCLUSION: Radioiodine therapy of feline hyperthyroidism is highly effective and safe. It can easily be performed in accordance with German radiation protection regulations, although this requires hospitalisation for approximately two weeks. Practical considerations on radiation exposure of cat owners do not justify this long interval. Regulations for the veterinary use of radioactive substances similar to existing regulations for medical use in humans are highly desirable.