Takashi Hidaka

MORPHOMETRIC ANALYSIS OF HUMAN NEUROMUSCULAR JUNCTION IN DIFFERENT AGES

Application of morphometric analysis to the study of neuromuscular junction is helpful to the quantitative approach of ultrastructural changes. In this study, twelve autopsied subjects of different ages were examined on the ultra‐structure of neuromuscular junctions using morphometric analysis. The postsynaptic area and postsynaptic membrane length were significantly greater in adults than in infants. The results indicate that the number and/or depth of the secondary synaptic clefts of adults are greater than those of infants. In the aged subjects, presynaptic membrane length and postsynaptic membrane density showed a significant decrease. The latter observations were thought to be the results of regressive changes of pre‐ and postsynaptic structure with aging. The variations of each structural element were also studied. The large variations were found in the postsynaptic area, postsynaptic membrane length, and membrane length ratio of adults and aged group. On the other hand, variations in postsynaptic membrane density were small in all age groups. The importance of the knowledge of these age related changes and variations in the studies of neuromuscular junction was discussed. ACTA PATHOL. JPN. 34: 1243–1249. 1984.

GRANULE FORMATION IN RAT MAST CELLS — Study with Serial Ultrathin Sections —

The process of granule formation in mast cells was investigated with young mast cells in the milky spot of adult rats, seven days after an intraperitoneal injection of distilled water. Serial ultrathin sections were made and examined with an electron microscope to reveal the following results. The early step of granule formation is observed as a complex which consists of an irregularly shaped narrow vestibular space and several primary aggregate granules which are bowl‐like in form, attached to the vestibular space and contain a few subgranules. The vestibular space has microvilli. The precursor materials seem to be secreted from the microvilli and transported through the vestibular space into the primary aggregate granules, being coagulated to become subgranules. As the subgranules increase in number, the primary aggregate granules become aggregate granules which grow further to their maximum size. With further addition of the materials, the aggregate granules become, through a step of ropy cord granule, mature dense homogeneous granules. The complex seems to remain as a unit after the maturation of granules and to react as a whole to any stimulus.