The structure and composition of the capsule of Trichinella spiralis in host muscle

The results of ultrastructural studies and histochemical tests on the capsule of Trichinella spiralis are given. The capsule wall is shown to consist of two layers, an outer region of tightly compacted fibrils and an inner region of fibrils dispersed through matrix cytoplasm. Histochemical tests show the capsule wall to consist mainly of collagen and cystine. The appearance of the matrix, which is packed with mitochondria, rough endoplasmic reticulum, smooth reticulum and Golgi complexes, together with the histochemical reaction to the five enzymes tested, strongly suggests that the matrix is a region of high metabolic activity. Although there are several very large nuclei in the matrix there is no evidence of cell walls; consequently the matrix is a syncytium.

I wish to thank the A.R.C. for financial support while this work was carried out. I should also like to thank Dr D. L. Lee for his advice on many occasions and the late Professor Boyd of the Anatomy Department, University of Cambridge, for the use of the electron microscope in that Department.

Radiology in diagnosis and control of surgical treatment of subphrenic and liver abscesses

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Electron-microscopic structure of denervated skeletal muscle

(1) An electron-microscopic study was made of normal and denervated muscle fibres in the rat diaphragm. (2) Early after denervation muscle fibres become hypertrophic. The cross-sectional area of the fibres and the number of myofibrils within them are increased. Since filament spacing is not significantly altered, it is concluded that during hypertrophy the number of actin and myosin filaments is increased. (3) A few weeks after denervation the muscle fibres are greatly reduced in size. This atrophy is mainly a consequence of two processes: fragmentation of the muscle fibre, with subsequent degeneration of the fragments; and disintegration of myofilaments.