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Myostatin is a specific negative regulator of skeletal muscle growth and is regarded as one of the most important factors for myogenesis. The aim of the current study was to analyze the developmental change in the gene expression of myostatin and an adipogenic transcription factor (peroxisome proliferator-activated receptor γ 2) in the semitendinosus muscle of Japanese Black Cattle throughout the whole life cycle. An additional aim was to compare the temporal expression patterns of myostatin and relevant myogenic regulatory factors (MRF) mRNA during muscle regeneration after frostbite injury at 16 mo of age. The developmental pattern of myostatin gene expression exhibited 2 peaks: the greatest expression occurred in utero (P < 0.05) and the second greatest occurred at 16 mo of age (P < 0.05). The greatest level of peroxisome proliferator-activated receptor 72 expression was observed at 16 mo of age (P < 0.05), which paralleled myostatin expression. During frostbite-induced muscle regeneration, gene expression for myostatin and 4 MRF; i.e., Myf5, MyoD, myogenin and MRF4, showed contrasting responses. Myostatin mRNA dramatically declined by 68.1 and 82.6% at 3 and 5 d after injury (P < 0.05), respectively, which paralleled its protein expression, and was restored at 10 d. In contrast, the expressions of all 4 MRF mRNA were low initially but increased by 5 d after injury (P < 0.05) and then remained constant or decreased slightly. These results suggest that myostatin may play a role in muscle marbling in the fattening period by decreasing myogenesis and increasing adipogenesis, and that the interaction between myostatin and MRF genes may take place at an early stage of skeletal muscle regeneration. [ABSTRACT FROM AUTHOR]

Nine periodontally affected subjects and eight healthy subjects were selected in order to examine the effect of initial periodontal treatment on occlusal sounds. Gingival Index, probing depth, tooth mobility and occlusal sound duration via an occlusal sound analyser were recorded at the baseline. The nine periodontal patients were then treated by plaque control, root planing with general scaling and were re-examined at 1 month and 3 months post-operatively. The following results were obtained: (i) The normal duration of an occlusal sound is less than 10 ms. (ii) Occlusal sounds of periodontal patients were of longer duration compared with the values in healthy subjects, but decreased and approached the normal value after treatment. [ABSTRACT FROM AUTHOR]