Arrhythmogenic right ventricular cardiomyopathy is an uncommon diagnosis in the paediatric population, most commonly presenting with arrhythmia. We report an 11-year-old male presenting with right heart failure due to biventricular systolic dysfunction found to have arrhythmogenic right ventricular cardiomyopathy with de novo Desmin and MYH7 mutations.

The present study was conducted to determine the effect of growth rate of calves on the activity of the calpain system post mortem, post mortem desmin degradation, myofibrillar fragmentation index and meat tenderness of m. longissimus lumborum (LL) and m. supraspinatus (SS). Twenty-four Friesian heifer calves were allocated to two treatment groups: MM and HH. The MM calves were given food to achieve a moderate growth rate (678 g/day from 5 days of age to 90 kg body weight (BW) (period I) and 770 g/day from 90 kg BW to slaughter at 250 kg BW (period II)) and the HH calves were given food to achieve a high growth rate (period I: 895 g/day and period II: 1204 g/day). The myofibril fragmentation index (MFI), desmin degradation and the activity of µ-calpain, m-calpain and calpastatin were measured in LL and SS at slaughter, and 1 and 7 days post mortem. Shear force was measured in LL and SS after 1 and 7 days of ageing and a sensory panel evaluated the eating quality of the loin aged 7 days. MFI (P < 0·01) and tenderness (P < 0·01) were higher and shear force was lower (P < 0·001) in meat from HH calves compared with meat from MM calves. However, growth rate did not affect the activity of µ-calpain, m-calpain or calpastatin or the degradation pattern of desmin at any time post mortem. Besides growth rate and MFI at day 7 post mortem, which both correlated positively with meat tenderness (P < 0·001 and P < 0·01, respectively), fibre type traits and DNA or RNA concentrations were not generally related to final tenderness. Thus, it was concluded that increased growth rate of calves before slaughter increased the ease of fragmentation (MFI) of the meat and improved the tenderness but these findings could not be related to any changes in the activity of the calpain system.

The difference in the timing of the regeneration process of skeletal muscle between SJL/J and BALB/c mice was investigated using grafts of whole skeletal muscle (both autografts and allografts). Histological, autoradiographic and immunohistochemical techniques were used in the investigation. Infiltration of leucocytes into autografts, numbers of desmin-positive myogenic cells and myotube formation were all more advanced in the SJL/J compared with BALB/c mice. Furthermore, autoradiographic evidence showed that myoblasts in the SJL/J autografts were synthesising DNA 12 h earlier than myoblasts in BALB/c autografts. In allografts, where SJL/J host mice received BALB/c grafts, and vice versa, leucocyte infiltration and myotube formation occurred earlier in the BALB/c muscles grafted into SJL/J hosts, than in the reverse situation with BALB/c hosts. The results show that, at least for whole muscle grafts, it is the host environment which determines the speed and outcome of the regenerative process.

We describe a leiomyosarcoma of the tongue in a 60-year-old man. The diagnosis was supported by immunohistochemical positivity for desmin and alpha-1 smooth muscle actin.