A comparative electron microscopic study was made on the effects of saponin on the sinusoids and capillaries of various organs of rabbits and the sinusoids of the bone marrow in cats, dogs, rats and mice. Animals received an intravenous injection of saponin at a dose of 2 mg per kg of body weight and were sacrificed 6 hours after injection.
In rabbits, the sinusoidal endothelium of the bone marrow showed extensive damage, whereas the endothelial cells lining the liver sinusoids, those lining discontinuous capillaries in the small intestine and adrenal cortex, and those lining continuous capillaries in the muscles (diaphragm and biceps brachii muscle) remained unaffected. Among the various animals exathined, only in the case of cats did saponin induce results similar to the marrow sinusoid damage found in rabbits.

View full abstract

It is already known that the human plantar aponeurosis can be divided into the tibial aponeurosis and the fibular aponeurosis and that there are marked variations in the latter. These variations were classified into four types by Loth (1931). However, there have been no investigations of these variations strictly according to his classification in the case of the Japanese. This investigation was carried out on the variations of the plantar aponeurosis strictly following Loth's classification, using cadavers of Japanese in the Kyushu region. The results reveal that there are racial differences in a broad sense between Japanese and Europeans. The strong anterior part of the fibular aponeurosis appears more frequently in the Japanese. The frequency of the absence of the anterior part is also higher in the Japanese. These facts indicate that the fibular aponeurosis of Japanese is more variable than that of Europeans. It seems that there is no difference in the variation pattern of the fibular aponeurosis between the left and right sides.

View full abstract

Many studies have been undertaken on the evolution of the articular cavity, and two theories, i. e,. liquefaction and dehiscence, for the process of formation have long been disputed. In the present study, the process of articular cavity formation was investigated in White Leghorn embryos as well as cat embryos that were fixed favorably and in cat embryo that was fixed unfavorably.
The materials used were 40 White Leghorn embryos, of which one each was fixed every six hours from a six-day, zero-hour embryo to a 15-day,18-hour embryo, and five cat embryos of 54 mm,57 mm,59 mm,62 mm and 100 mm in crown-rump (C. R. ) length. Taking account of the procedure of fixation, the whole body in some of the embryos or the head alone in others was embedded in paraffin, sectioned serially at 10μm and stained by Masson-Goldner's and Loots-Loots-Joubert's methods.
In every one of the cat embryos, the upper articular cavity had already formed, suggesting that the lower articular cavity was in the process of development. All of the cells around the lower articular cavity were spindle-shaped. The long axes were parallel to the articular surface, and there was no liquefaction of the cells in the embryos fixed favorably.
In the embryos fixed unfavorably, many cells were spindle-shaped, but the directions of the long axes were not constant, and part of the cells showed liquefaction. In the seven-day, zero-hour White Leghorn embryo, the relation between the articular fossa and the articular caput had begun to form and the primitive articular cavities, which were considered to have arisen as a result of dissociation of the connection among cells, were observed in the mediating mesenchymal tissue. These apertures became fused with each other with time. The cells in contact with or adjacent to the apertures were spindle-shaped. In the 11-day,12-hour embryo, the cells that backed the quadrate articular cavity in the middle of the articulation section were differentiated into chondrocytes and proliferated as if they were invading the mediating mesenchymal tissue. During and after this stage, the articular cavity in the anterior part of the articulation tended to expand. Differentiation proceeded further, and the apertures in the mediating mesenchymal tissue in the middle and posterior parts of the articulation disappeared in the 14-day embryos. However, the cells were spindle-shaped. The cells facing the articular cavity in the anterior part, located in the middle of the articulation, were also spindle-shaped. However, there was no liquefaction of the cells at any of these stages.
From the above results, it was concluded that the articular cavity of the jaw articulation is formed by dehiscence of the tissue or dissociation of the intercellular connections.

View full abstract

The distal colon of the developing rat embryo was studied by electron microscopy on specimens taken at each gestational day from 11 to 21. The circular muscle and Auerbach's plexus were identified in the mesenchyme on day 15. Prior to this, nerve cells were not easily distinguishable in the colonic wall. However, many clear cells in the subserosa were found to have abundant microtubules and filaments in the cytoplasm and also in their processes. These cells were presumed to be a primitive form representing undifferentiated migratory neuroblasts.
To examine whether neuroblasts were present in the distal colon before day 15, colons were dissected from day 14 embryos and cultured in vitro for 1 to 3 days. Circular muscle and Auerbach's plexus differentiated after 3 days in culture. These findings support the view that undifferentiated neuroblasts have already migrated into the colonic mesenchyme by day 14, although their morphology is equivocal.

View full abstract

The detection of avidin in the hen oviduct was studied by immunohistochemistry. Antigenic avidin was demonstrated in secretory granules of both gland cells and nonciliated epithelial cells in the magnum. These immunospecific granules were electron dense and nonhomogeneous especially in acinar cells, and the size varied from small to large(0.7 to 2.2μm in diameter)in the gland and small(200 to 700 nm) in the epithelium. Epithelial cells containing secretory granules had a strong resemblance to those of the protodifferentiated gland cells appearing in the magnum of chicks pretreated with hormones. No avidin was observed in any epithelial goblet cells or ciliated cells. The findings paralleled those obtained by biotinylatedenzymes affinity cytochemical methods as previously described (Kami and Yasuda,1982).
Therefore avidin in the hen's oviduct is one of the proteins produced and stored in the secretory granules of the gland cells and protodifferentiated acinar cells located in the epithelial layer, although initiation of the synthesis may be triggered by progesterone. However, it is still not clear whether different hormone-dependent proteins are located in the same granules or not.

View full abstract