Dental arch length, bilateral intermolar distance, morphology of the anterior teeth, and bilateral intercanine distance have been reported as factors influencing the determination of dental arch form. However, studies evaluating the factors that influence the determination of the above-mentioned components are limited. Therefore, to verify these points, the present study aimed to examine factors influencing the determination of dental arch form using statistical methods.Data obtained from sample dental casts were analyzed using principal component and cluster analyses. By principal component analysis, 23 sets of information were summarized into three components for the maxilla and four for the mandible. As a result of cluster analysis using principal component scores, the maxillary and mandibular dental arches were classified into four forms, respectively.Dental arch length is an important indicator of dental arch size and is influenced by the bilateral interincisor distance of the maxilla and mandible, and the mesiodistal crown width of the incisors and premolars. In the mandible, canine width also affects dental arch length. Dental arch width also influences the determination of dental arch form. However, the distance between the anterior teeth and the distance between the molars are independent and have no effect on each other.

The liver architecture of vertebrates can be classified into two types, the portal triad type (having periportal bile ducts) and the non-portal triad type (having non-periportal bile ducts). The former is detectable in the tetrapod liver whereas the lungfish liver has the latter. It remains to be revealed which type of hepatic architecture the coelacanth, which together with the lungfish belongs to the Sarcopterygii, possesses. The present study was undertaken to determine the histological characteristics of the coelacanth liver, and to compare with those of other vertebrates. The coelacanth liver had periportal bile ducts and ductules as detected in mammalian livers. The hepatic artery was found around large portal veins. Hagfish, shark, bichir, sturgeon, bowfin and frog livers had periportal bile ducts and bile ductules, whereas most intrahepatic bile ducts of the lungfish were independent of the distribution of the portal veins as seen in the Otocephala and Euteleostei. The lungfish liver developed duct and ductule structures in the parenchyma. These data indicate that the coelacanth liver had a mammalian-type hepatic architecture with a portal triad, and that the ancestors of tetrapods may have had a portal triad-type liver architecture.

Embryo implantation is an immunologically paradoxical event. In humans and rodents, blastocysts adhere to uterine epithelium and then invade into endometrial stroma, while maternal body is protected from extraneous materials by its immune system. Eosinophils, a kind of leucocytes involving parasitic infections and allergic response, increase in number in uterus when serum estrogen level is elevated during estrus cycles. However, response of uterine eosinophils to ovarian estrogen during peri-implantation period is not clear. Therefore, we investigated the distribution of eosinophils in murine peri-implantation uterus. On day 0.5 of pregnancy, eosinophils were found primarily in endometrial stroma near the luminal epithelium, whereas they were primarily distributed in basal endometrium and myometrium on day 3.5 of pregnancy. The number of uterine eosinophils on day 4.5 of pregnancy was significantly increased by inhibition of maternal estrogen action. Collectively, our results indicate that the ovarian estrogen negatively regulates uterine eosinophil distribution during peri-implantation period and provide insight into a role of maternal immune system in embryo implantation.

In Japan, 13 million people have osteoporosis, including approximately 9 hundred thousand people who are bedridden owing to bone fractures from falls. Preventing osteoporosis is considered to be an important and effective way of preventing fall-related fractures. Thus, we developed a novel method of locomotor stimulation and analyzed its effectiveness in mice. Specifically, we created a double-loading device that combines vibration and shaking stimulation. The device was used to continuously stimulate ovariectomy-induced decreased bone density mouse models 30 minutes daily for 10 weeks. We then collected femur samples, created undecalcified tissue slices, calculated parameters using bone histomorphomtry, and conducted comparative testing. BS/TV (bone surface/tissue volume), N.Oc/ES (osteoclast number/eroded surface), Oc.S/ES (osteoclast osteoid surface/eroded surface), Omt (osteoid maturation time), Tb.N (trabecular number), Mlt (mineralization lag time) < (p < 0.01), N.Ob (osteoblast number), N.Ob/TV (osteoblast number/tissue volume), sLS (single labeled suface), N.Mu.Oc/ES (multinucle osteoclast number/eroded surface), and N.Mo.Oc/ES (mononucle osteoclast number/eroded surface) (p < 0.05) were significantly higher in the stimulation group than in the non-stimulation group. In addition, BS/BV (bone surface/bone volume), Tb.Sp (trabecular separation), MAR (mineral apposition rate), Aj.Ar (adjusted apposition rate) (p < 0.01), ES (eroded surface ), ES/BS (eroded surface/bone surface), and BRs.R (bone resorption rate) (p < 0.05) were significantly lower in the stimulation group than in the non-stimulation group. These results suggest that stimulation activated osteoblasts and osteoclasts, thereby leading to highly active bone remodeling. We anticipate that bone mineralization will subsequently occur, suggesting that this stimulation technique is effective in preventing osteoporosis by alleviating sudden bone density loss.

Author examined the dorsal lingual surfaces of the adult Japanese lesser flying squirrel (Pteromys momonga) and four-toed hedgehog (Atelerix albiventris) by scanning electron microscopy. In the Japanese lesser flying squirrel, the filiform papilla of the lingual body consisted of a large conical papilla. The filiform papilla of the lingual prominence was spoon in shape. The fungiform papillae were round in shape and scattered among the filiform papillae. Many foliate papillae were observed on the posterolateral regions of the lingual body. The foliate papillae had some ridges separated by deep grooves. The vallate papilla was located between lingual body and root. Several long conical papillae derived from the posterolateral margin of the tongue. In the four-toed hedgehog, the filiform papilla of the lingual apex had a conical process. The filiform papilla of the lingual body had some processes. The fungiform papillae were round in shape. The foliate papillae were observed on the posterolateral regions of the lingual body. The papilla was separated from each other by a furrow. The vallate papilla consisted of a central papilla and an annular pad. These findings suggest that in the structure of the lingual papillae of the Japanese lesser flying squirrel there is similar to that of the sugar glider and the lingual papillae of the four-toed hedgehog is different from that of the Japanese lesser flying squirrel.

We examined the dorsal lingual surfaces of an adult bharal (Pseudois nayaur) by scanning electron microscopy. The filiform papillae of the lingual apex and body consisted of a main papilla and smaller secondary papillae. The filiform papilla of the lingual body was big as compared to that of the lingual apex. The connective tissue cores of the filiform papillae consisted of several processes. The fungiform papilla was round in shape. The connective tissue cores of the fungiform papillae were flower-bud shaped. The lenticular papillae of large size were limited on the lingual prominence. The connective tissue cores of the lenticular papillae were hair-like in shape. The vallate papillae were located on both sides of the posterolateral aspects. The vallate papillae were flattened-oval shaped and the papillae were surrounded by an oval-shaped trench. The connective tissue cores of the vallate papillae were covered with numerous small spines The lingual surface of the bharal closely resembled that of the family Bovidae.

Okajimas Folia Anatomica Japonica was first published in 1922 through the private funding of Professor Keiji Okajima, the first head of the Department of Anatomy, Keio University School of Medicine. Back then it was the only western-language anatomical journal available in our country, through which the researchers could present their achievements worldwide. To this date, for about 100 years, it has been published periodically by the editorial committee in the department.  This time, the committee decided to put a break constructively; we suspend publication of this journal while anticipating the future resumption as a form adapted to the times. Accordingly, we have closed new submissions on September 30, 2019. Thank you for understanding and continuous support for Okajimas Folia Anatomica Japonica.

We examined the dorsal lingual surfaces of an adult Chapman's zebra by scanning electron microscopy. The filiform papillae of the lingual apex consisted of a main papilla and smaller secondary papillae. The fungiform papillae were round in shape. The filiform papillae of central region of the lingual body were needle-like in shape. The filiform papillae of posterior region of the lingual body were hair-like in shape. Many grooves were observed on posterolateral regions and the fungiform papillae were observed on the inside of some grooves. The vallate papillae were located on both sides of the posterior region and surrounded by a groove. The anatomical characteristic of the lingual surface of the Chapman's zebra is the fungiform papillae on the inside of some grooves.

We microscopically examined the dorsal lingual surface of an adult Asian golden cat (Catopuma temminckii). The papillae on the margin of the lingual apex were horny-shaped and fungiform. The filiform papillae on the anterior part of the lingual body were large and cylindrical; the connective tissue core of each of these comprised a large conical papilla. The filiform papillae on the central part of the lingual body were large and conical-shaped on the medial side and dome-shaped on the lateral side. The connective tissue core of each medial filiform papilla comprised a large main process and some secondary processes, while processes were absent on the lateral side. These findings are peculiar to the tongue of members of the family Felidae.

We microscopically examined the dorsal lingual surface of an adult lion-tailed macaque (Macaca silenus). The tongue of the chimpanzee was about 13 cm long. Filiform papillae on the lingual apex consisted of several pointed processes. There were dome-shaped fungiform papillae scattered among the filiform papillae. The connective tissue cores of those filiform papillae consisted of processes of various size, while these of the fungiform papillae had several ditches. The vallate papilla was surrounded by a groove and pad, and were flattened-oval shaped. The connective tissue cores of the vallate papillae were covered with numerous small spines. Many foliate papillae were observed on the posterolateral regions of the tongue. After removing epithelium from the foliate papillae many processes became apparent.