Changes in the number of lymph follicles and germinal centers in draining popliteal lymph nodes were investigated in 8-week-old mice injected with either phytohemagglutinin (PHA) or lipopolysaccharide (LPS) into the footpad of the left hind leg. The dose of PHA injected ranged from 10μg to 1mg, and that of LPS, from 2 to 200μg. In unstimulated animals, the popliteal lymph nodes contained only a small number of germinal centers, and many of the lymph follicles in the nodes were in the form of primary follicles. In the draining lymph nodes, regardless of the dose injected, PHA induced germinal center development in existing primary follicles, but eventually failed to stimulate the formation of new lymph follicles and germinal centers. On the other hand, LPS not only induced germinal centers in the existing follicles, but also stimulated the formation of new primary follicles, many of which then developed germinal centers. The occurrence of new follicles in the LPS-treated lymph nodes was dose-dependent, and LPS appeared to cause de novo formation of follicles.
Lymphatic vessels afferent to the popliteal nodes in young adult rats and guinea pigs were interrupted at the lowest edge of the popliteal fossa, and regressive changes in the nodes occurring 4 to 16 or 18 weeks after surgery were re-examined histologically. In the rat, some popliteal nodes were drained by lymphatic channel(s) from the tail. After surgery, the popliteal nodes without lymphatic channel(s) from the tail underwent regression of all their constituent deep cortical units and also the peripheral cortex comprising lymph follicles, until at 18 weeks, the lymphoid organization of the node reached a minimal level. On the other hand, in popliteal nodes having a lymphatic channel from the tail, some deep cortical units and the overlying peripheral cortex underwent hypotrophy, leaving the remaining units and their overlying peripheral cortex little affected. In the guinea pig, the treated nodes underwent progressive atrophy and ultimately became rudimentary, or even vanished, after 16 weeks. Treated rudimentary nodes were composed largely of stromal cells only, and these were replaced to a various extent by fat. The present results are discussed in relation to complete and incomplete inhibition of the afferent lymph flowing into the surgically treated nodes.
Secular unchangeability of relative sitting height (a ratio of sitting height to stature) of 407 female Kyushuites were studied. Anthropometric studies of the sitting height and the stature were made on 110 female Central Kyushuites in 1955 and on 297 female Northern Kyushuites in 1973 and in 1980. These data were compared with those of the standard values of about 1000 female Japanese in 1942-45. There was no secular change in the relative sitting height, while the sitting height and the stature had increased.
The topographical anatomy of the chorda tympani nerve (CTn) was investigated macroscopically in 45 ears of Japanese adult cadavers, aged 38-88 yr, with special reference to its topographical relationship to critical structures encountered in otorhinolaryngological practice such as the auditory tube and Wharton's duct. Fifteen cases of the “separated type” of CTn running independently along the posterior margin of the lingual nerve, which were noted in our previous study, were included among the 45 specimens. Major findings considered relevant to clinical practice are described below.1. The course of the CTn, passing inferiorly and medially in the petrotympanic fissure, was classified into 2 types: that traveling immediately anterior to and parallel with the auditory tube, and the becoming progressively more distant (inferior and anterior) to the auditory tube.2. Immediately after emerging from the petrotympanic fissure, the CTn cons istently communicated with the sympathetic plexus around the middle meningeal artery, and often issued twigs reaching the otic ganglion area.3. In cases where the CT n was trapped by tendinous tissue around the lateral pterygoid muscle (17.8%), the nerve merged into the lingual nerve from the medial or anterior aspect, and not from the usual posterior aspect, at the level of the mandibular notch.4. The lingual nerve sometimes (20.0%) showed a strongl y curved sigmoid course behind the mandibular ramus. Several buccal branches innervating the oral lining, without containing the CTn element, were issued at the anterior projecting protion of the sigmoid course.5. At the base of the oral cavity, the major CTn element traveled al ong the superior margin of the lingual nerve, therefore the CTn element was located away from the submandibular ganglion.6. A thick communicating branch on both sides of the lingual nerve was rarely observ ed under the mucous lining or in the mucous layers at the tip of the tongue. These findings suggest that morphological variations of the CTn should be considered during surgical procedures and for understanding the nature of related clinical symptoms.
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