Search PubMed⌕ Search

Biomedical subjects

Y Yajima

Publications and source records attributed to Y Yajima.

At least 181 records · Page 10Linked to original sources
PubMed1981

Collagenolytic enzyme activity in human ovary: an ovulatory enzyme system.

Collagenolytic enzyme activities presumed to play an important role in ovulation were investigated in the human follicular apex, base, and granulosa cell layer throughout the ovarian cycle. Those analyzed were human ovarian collagenase, 2,4-dinitrophenyl-Pro-Gln-Gly-Ile-Ala-Gly-Gln-D-Arg-OH peptidase, N-carbobenzoxy-Gly-Pro-Gly-Gly-Pro-Ala peptidase, and alpha-N-benzoyl-DL-arginine beta-naphthylamide hydrolase. Collagenase activity was also measured in human granulosa cell cultures. The activities of all four enzymes showed a marked preovulatory decrease in the apex. The activities in the apex were slightly higher than those in the base throughout the ovarian cycle. However, the activities in the granulosa cell layer and collagenase activity in the granulosa cell cultures increased toward preovulation and decreased after ovulation. These findings suggest that collagenase is synthesized in the granulosa cells maximally at preovulation and is consumed in the follicular apex at the same time, resulting in collagen degradation and disruption of the follicular wall in collaboration with other collagenolytic enzymes investigated here.

Aminopeptidases↗
PubMed1981

Pleiotropic expression of Epstein--Barr virus DNA in human epithelial cells.

We have attempted to establish a system that can be used to study the association of Epstein--Barr virus (EBV) with epithelial cells. Attempts were made to transfect human carcinoma cells with EBV DNA. Successful transfection was confirmed by the expression of EBV-specific early antigen (EA), virus capsid antigen, and the presence of virus DNA. The transfecting preparation contained a mixture of EBV and cellular DNA extracted from two producer cell lines, P3HR-1 and AG-876. Our data suggest that virus DNA obtained from the P3HR-1 nontransforming, EA-inducing strain of EBV was lytically expressed in the epithelial tumor cells. The DNA derived from AG-876 cells, which produce a transforming, non-EA-inducing strain of EBV, also produced a lytic infection.

Carcinoma↗
PubMed1981

Treatment of adult-type citrullinemia with administration of citrate.

A 48-year-old man who showed a regular diurnal fluctuation of blood ammonia level was diagnosed as adult-type citrullinemia with quantitative estimation of plasma amino acids and urea cycle enzymes in the liver. The restriction of daily protein intake less than 50 g and oral administration of lactulose had no effect on the blood ammonia level. The efficacy of four amino acid solutions which had been used in order to improve the hepatic encephalopathy was compared each other in this case. Glutamate-arginine mixture had the same effect as glutamate solution in lowering the blood ammonia level, and glutamate was thought to be essential. Also, oral administration of citrate showed a remarkable effect almost comparable to intravenous administration of glutamate. Analysis of plasma amino acids 3 hr after citrate administration demonstrated an increase in glutamate and a decrease in citrulline. These observations suggest that a metabolic pathway of citrate-alpha-ketoglutarate-glutamate-glutamine takes part in disposing free ammonia in the blood.

Amino Acids↗
PubMed1981

[DNP-peptidase activity in the rabbit ovary (author's transl)].

To examine the possible roles of collagenolytic enzymes in the follicular wall at ovulation, we measured in rabbit ovaries collagenolytic enzymes by using synthetic substrates, DNP-Pro-Gln-Gly-Ile-Ala-Gly-Gln-D-Arg OH supposed to be specific for vertebrate collagenase. Our results clearly demonstrated that DNP-peptidase activity existed, with its optimal pH7.6-pH7.8 in rabbit ovarian follicles. DNP-peptidase activity steadily increased for nine hours following the hCG injection. After nine hours of enzyme activity decreased sharply until about the tenth hour, at which time ovulation had occurred. This pattern of enzyme activities indicates that the DNP-peptidase was consumed for degradation of collagen fibers. After collagen fibers have been completely degraded, this enzyme was increased again. These changes of DNP-peptidase activities at ovulation were similar to cathepsin B1 activities with its optimal pH6.0. It is concluded that DNP-peptidase could be one of ovulatory enzymes in the rabbit.

Animals↗
PubMed1980

The midbrain central gray substance as a highly sensitive neural structure for the production of ultrasonic vocalization in the rat.

To test whether there were any functional differences between the central gray substance (PVG) and other neural structures for the production of ultrasonic vocalization in the rat, an electrical stimulation experiment was systematically undertaken in diencephalic and mesencephalic tegmental regions. The sound production sensitivity to electrical stimulation was the highest in PVG. This suggested that the periventricular fiber system of Schütz's bundle might be a possible neural structure underlying sound emission in the rat.

Animals↗
PubMed1980

Ovulatory changes in the wall at the apex of the human Graafian follicle.

The apical wall was studied ultrastructurally in 16 human follicles at various stages of development. In the theca externa and tunica albuginea at the apex of growing follicles, fibroblasts with little cytoplasm and abundant collagen fibres were observed. In the mature follicles, the fibroblastic cytoplasm was well developed, rich in lysosome-like granules and contained peripheral multivesicular structures. Intercellular collagen fibres were sparse. It is suggested that the collagen fibres are digested by the content of lysosomal granules and multivesicular structures, thus aiding follicular rupture.

Adult↗
PubMed1980

[Activities of collagenolytic enzymes in the human ovary (author's transl)].

To elucidate the mechanisms of follicular rupture at ovulation in human, activities of collagenolytic enzymes were measured in the human follicles at various stages of development by using two kinds of synthetic substrates, alpha-N-benzoyl-DL-arginine-2-naphthylamide HCl and N-carbobenzoxy-glycyl-prolyl-glycyl-glycyl-prolyl-alanine. The result clarified that human ovaries did have two kinds of collagenolytic activities, one cathepsin B1 with its optimal pH 6.0, the other neutral collagenase with its optimal pH 7.5. To examine the subtle changes of these enzymatic activities in the follicles during ovulatory processes, the follicle wall was dissected into three parts, namely, the granulosal layer, the apical wall and the basal wall without the granulosal layer. Activity of neutral collagenase presented a continuous increase in the follicular wall, while in the granulosal layer its gradual depletion was observed. Cathepsin B1 revealed a significant drop of its activity in the apical wall around a preovulatory period. These results indicate an involvement of collagenolytic enzymes in the human ovulatory process.

Cathepsin B↗
PubMed1980

[Activity of vertebrate collagenase in the human ovary (author's transl)].

Participation of collagenolytic activities in the ovulatory process had been recently studied in the experimental animals, though their existence in the human ovary remains obscure. In the previous report, we demonstrated the collagenolytic activity by using synthetic substrates N-carbobenzoxy-Gly-Pro-Gly-Gly-Pro-Ala and the cathepsin B1 activity in human ovarian follicles. To investigate the activity for degradation of native collagen in the human ovary, we used 14C-labeled collagen prepared from young rat skin in the present study. Collagenolytic activity for synthetic substrate DNP-Pro-Gln-Gly-Ile-Ala-Gly-Gln-D-Arg OH supposed to be specific for vertebrate collagenase was also measured. Our results clearly demonstrated that there existed vertebrate collagenase activity and the collagenolytic activity measured by using DNP-peptide in the human ovarian follicles. The correlation coefficient between both enzymatic activities was 0.56. The DNP-peptide-degrading activity seemed to partly represent the collagenolytic activity from vertebrate collagenase. It was concluded that vertebrate collagenase besides collagenolytic activities did exist in the human ovary and they seemed to be involved in the degradation of collagen fibers in the follicular apex at the time of ovulation.

Animals↗
PubMed1980

[An ultrastructural study of ovulatory changes in stromal tissue of the follicular apex in the human (author's transl)].

To elucidate the mechanism of follicular rupture at ovulation in human, ultrastructural changes of stromal tissue of the follicular apex during follicular growth and ovulation were studied by focusing on the collagen and fibroblasts in the stroma. Sixteen ovaries were obtained from women at their thirties who underwent the abdominal hysterectomy for gynecologic diseases. From follicles at various stages of development, apical portions were excised and processed for electronmicroscopy. At the apex of growing follicles, fibroblasts with poor cytoplasm and abundant collagen fibers among them were observed in the layers of tunica albuginea and theca externa. At the preovulatory follicles, fibroblasts had rich cytoplasm containing lysosomal granules and multivesicular structures and intercellular collagen fibers were rather sparse. These lysosomal granules and multivesicular structures in the fibroblasts were much conspicuous in the theca external layer of preovulatory and post-ruptured follicles and collagen fibers among these fibroblasts were almost disappeared. It seems that these intercellular collagen fibers and ground substance were digested by the content of lysosomal granules and multivesicular structures.

Adult↗
PubMed1980

[A cytochemical study of acid-phosphatase activity in follicular granulosa cells of human ovaries (author's transl)].

In order to clarify the nature and possible roles of lysosome-like granules observed electronmicroscopically in the granulosa cells of human preovulatory follicles, lysosomal activities in human preovulatory granulosa cells were investigated ultrastructurally by staining a marker enzyme acid phosphatase with modified Gomori technique. In the granulosa cells of follicles 10 approximately 15 mm in diameter, acid phosphatase reaction products were seen only in the Golgi apparatus. In follicles around 20 mm in diameter with extremely thin apical walls, granulosa cells with abundant nexuses and steroidogenic organelles (sER, large spherical mitochondria with tubular cristae and lipid-droplets), had many lysosome-like granules in the perinuclear regions and/or close to lipid droplets. Acid phosphatase reaction products were observed mainly in these granules, and infrequently in Golgi apparatus. These morphological results not only identify such granules as lysosomes, but also indicate that the granulosa cells are rich in the lysosomal activity. Possible roles of lysosomes in preovulatory granulosa cells deduced from the present results are as follows, 1) a role in steroidogenesis or in steroid-secretion, 2) an involvement in the ovulatory process with their proteolytic enzymes.

Acid Phosphatase↗
PubMed1979

[The vasopressor role of ADH in the maintenance of blood pressure in experimentally hypertensive rats (author's transl)].

In order to investigate the vasopressor role of ADH in the regulation of blood pressure, passive immunization experiments with an antibody to AVP were carried out in experimentally hypertensive rats. In hypertensive rats treated with deoxycorticosterone acetate (DOCA), spontaneously hypertensive rats (SHR) and spontaneously hypertensive stroke-prone rats (SHR-sp), the intravenous injection of a specific vasopressin antibody resulted in a transient fall of blood pressure of 11 approximately 25mmHg, while in rats with two-kidney Goldblatt hypertension and normal rats, the blood pressure was not affected. This strongly suggests that ADH contributed to systemic vaso-constriction in DOCA hypertension and spontaneous hypertension in rats.

Animals↗
PubMed1978

Transforming activity of Epstein-Barr virus obtained by superinfection of Raji cells.

Epstein-Barr virus obtained by superinfection of Raji cells with Epstein-Barr virus recovered from P3HR1 cells (HRI virus) transformed human lymphocytes, but it did not superinfect Raji cells. A human lymphoblastoid cell line, HLB, established by such transformation contained 22 Epstein-Barr virus genomes per cell and Epstein-Barr virus-associated nuclear antigen, and a few cells contained early or viral capsid antigen complexes. Chromosomal analysis revealed that HLB-cells were diploid with normal female karyotypes. Replication of Epstein-Barr virus DNA and inhibition of host cell DNA synthesis were observed in HLB cells after superinfection with HR1 virus.

Antigens, Viral↗