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Volume 15, Issue 1
Displaying 1-5 of 5 articles from this issue
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Mitsuo Sato, Masatsugu Takahashi1968 Volume 15 Issue 1 Pages 1-6
Published: November 29, 1968
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIn fifty animals, measuring 9-12 cm in total length, the distal one half of the right maxillary barbls was amputated under anesthetization with 0.1 per cent solution of chloretone. By eighteen hours after amputation, the end of the barbel stump was sealed by a layer of stratified squamous epidermis which contained small accumulations of blood. And the cut end of a central blood vessel which occupied a core of the dermis of the barbel was plugged with a coagulated mass of blood. Five days after amputation, most of coagulated masses of blood found in the space beneath the sealing epidrmis and in the cut end of blood vessel were gradually absorved and replaced by cells which were mainly derived from the connective tissue near the wound area. These cells, may represent the initial formation of the regeneration blastema. Accordingly, the connective tissue may be primary source of the cells for blastema formation. At this time, mitotic figures were observed in this tissue near the wound area. Once the blastema has been formed, the barbel regeneration progresses satisfactorily. From the present observation it is probable that new endothelial cells contributing to the growth of the central blood vessel did not arise from their own kind, but from the blastema cells. This problem needs further investigation. The regeneration of the smooth muscle layer which encircles the central vessel seemed to take place by both the differentiation of the blastema cells and the proliferation of the former muscle of the stump.Terminal buds occurred in the epidermis of the regenerate within fifteen days after operation. By the twenty-fifth day the histological structure of the regenerate became almost undistinguishable from that of the stump, and the regenerate elongated at an average rate of 0.06 mm per day.View full abstractDownload PDF (9757K) -
Yasuo Nakatsukasa1968 Volume 15 Issue 1 Pages 7-10
Published: November 29, 1968
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe author made a histological study of the tumor which grew in the muscular tissue of the lateral wall of abdominal cavity of a chum salmon. The following results were obtained. (1) The shapes of the cells in the tumor were round, oval or spindle. (2) From the various observations it was considered that the tumor developed in muscular tissue and grew into the kidney tissue with a infiltrative growth. (3) There was no clear difference between parenchyma and stroma in the tumor, which was, then, considered to be nonepitherial. (4) The study suggested the tumor as polymorphic-cell sarcoma.View full abstractDownload PDF (5888K) -
The Hypothalamic Neurosecretory System of the Koayu exposed to the Artificial PhotoperiodsYoshiharu Honma, Atsuyoshi Suzuki1968 Volume 15 Issue 1 Pages 11-27
Published: November 29, 1968
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe annual, land-locked salmonoid fish, the Koayu, Plecoglossus altivelis, reared in the outdoor hatchery ponds and exposed to short-(8 hours daily), long-photoperiodic regime (16 hours daily) and natural day-length (control) were examined to elucidate the activities of hypothalamo-hypophysial neurosecretory complex and a possible interrelationship between the hypothalamic nuclei and maturation of the fish. The period of experiment extended from July 2, 1966 to January 22, 1967. Five females and five males collected at monthly intervals were supplied to inspect the growth, maturity and histological feature of the neurosecretory system. High mortalities were encountered between the months September and November in the short photoperiodicity, October and December in the control, and December and January in the long photoperiodicity, respectively, in parallel with the highest level of gonadal maturation and of cyanophilic gonad stimulating cells. Untill each prespawning season, the perikarya and juxta-somal axons of the preopticonucleic cells heavy loaded with AF-stainable neurosecretory material have been observed in each experimental group.Early in each spawning season, fine droplets of material in smaller amount are scattered around the nuclei of the cells. After that, a notable depletion of the material from the perikarya and juxta-somal axons is detected. Recovery phase of the neurosecretion is seen in the female fish survived beyond each spawning time and tided over the winter. On the contrary, all of the males were deceased untill the next year. Changes in the amount of the storage material in the neurohypophysis appear to be parallel with those of neurons. During each breeding time, on the other hand, the highest activity is reached by the nucleus lateralis tuberis which were stained with acidic dyes. These results suggest that there is a role of the light rhythm upon the maturation of the Koayu via hypothalamic neurosecretory system, and the possibility of artificial control of the breeding time in the fish.View full abstractDownload PDF (12569K) -
Rekesh K. Rastogi, P. K. Saxena1968 Volume 15 Issue 1 Pages 28-35
Published: November 29, 1968
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSTeleosts ovary undergoes regular changes in many species, but the breeding season and spawning reflex are varied. The ovarian histomorphology and annual changes and the spawning periodicity of this catfish were studied on the total of 78 individuals collected monthly in one year period of 1963-64. By gross morphology and its seasonal changes, especially on the changes in cell structure in this species, nine separate stages were distinguished to categorise the developing oocytes. As to the annual ovarian changes, seven phases of ovarian cycle was described based on the percentage and duration of different stages of developing oocytes, average diameter of oocytes and nature of ovarian wall-Immature Virgin (October to February), Preparatory Virgin (March-April), Maturing Virgin (April-May), Prespawning Virgin (June), Spawning (late June through August), Depletion (late August-September), and Recoupment (October-November). The studies revealed a close correspondence among gonosomatic index, ova diameter and water temperature. Discussion was made on some interpretations as to the origin of new crops of oocytes in teleosts ovary. In Mystus the new oocytes were found to be formed from dividing oogonia, which were transformed from stroma cells; the fish lacked a well defined germinal epithelium. As to the spawning periodicities, of which examples in teleosts were introduced, the present species revealed to produce two or more batches of eggs during the same season (April to August or early September) by finding that only two types of ova are present in ripe ovaries, immature and mature, the latter containing oocytes in late yolk stage and mature stage, and by examining gonosomatic index, ova diameter and histological nature of ova. Finally, relative and total fecundity in bony fish were discussed, and the present study suggested that the unshed ripe oocytes undergoing atresia must be counted in computing the total fecundity. It was estimated that in Mystus nearly 93% oocytes finally ripen and are shed.View full abstractDownload PDF (4798K) -
Tatsuji Ueno, Koji Abe1968 Volume 15 Issue 1 Pages 36-37
Published: November 29, 1968
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (329K)
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