This study is based on the dissections of 645 pelvic halves of Japanese cadavers. The branching of the internal iliac artery was classified according to Adachi's classification (1928) , and the data was compared with previous reports. Type I was predominant in this , as well as, in previous studies. During the course of the present study, some branching forms were different from the types in Adachi's classification. Therefore, this classification was modified into 5 types and 19 groups. Type I-Group 1 was most frequently observed in the modified Adachi's classification, however, the frequency was less than 50% (46.8%). To clarify the basic branching pattern of the original internal iliac artery and to simplify the classification for medical purposes , a new classification system was designed. The superior gluteal, inferior gluteal and internal pudendal arteries were defined as the major branches of the internal iliac artery, and the umbilical artery was excluded from this group. The branching of the internal iliac artery was classified into 4 groups. Almost 80% of the present specimens were included in Group A of the new classification , namely, the internal iliac artery dividing into two major branches, the superior gluteal artery and the common trunk of the inferior gluteal and internal pudendal arteries. This type of branching seemed to be the basic branching pattern for the original internal iliac artery.

No abstract

We previously reported the chronological appearance of adenohypophysial cells in freshwater teleosts using an immunocytochemical technique. The present study investigated the chronological appearance of adenohypophysial cells in the ayu, which is spawned and has its early development in brackish water, and the results were compared with those obtained in freshwater and seawater teleosts, as well as in other vertebrates. In the adult teleostean adenohypophysis, seven or eight types of secretory cells have been distinguished, each of which produce different hormones: prolactin (PRL), growth hormone (GH), thyroid stimulating hormone (TSH), gonadotropic hormones (GTH I and GTH II), adrenocorticotropic hormone (ACTH), melanophore stimulating hormone (MSH) and somatolactin (SL). In the pituitary of adult ayu, seven distinct types of glandular cells (PRL, GH, TSH, GTH, ACTH, MSH and SL cells) were identified. Chronologically, a few immunoreactive (ir)-PRL and ir-GH cells appeared in the ventral side of the pituitary one day before hatching. Then, just after hatching, ir-GTH cells were observed in the central to dorsal portion; ir-ACTH cells were found distributed in the anterior portion and some ir-MSH and a few ir-SL cells were seen in the posterior portion of the pituitary. Finally, a small number of ir-TSH cells were identified 50 days after hatching. These results differed from those obtained in other fishes previously reported with regard to the times of appearance of the PRL and GH cells. PRL cells appeared first, followed by GH cells in the freshwater teleosts, PRL and GH cells appeared at the same time in the brackishwater teleosts, while GH cells appeared first and PRL cells appeared last in the seawater teleosts. These results reflect the fact that PRL plays a major role in osmoregulation among freshwater teleosts, as compared with GH, which plays a similar role in seawater teleosts. It seems that both PRL and GH may play important roles in osmoregulation in brackishwater fish.