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Biomedical subjects

K Ohkawa

Publications and source records attributed to K Ohkawa.

140 records · Page 8Linked to original sources
PubMed1981

[An ultrastructural study of penetration and replacement process by trophoblast cell into human maternal vessel (author's transl)].

To elucidate the mechanism of trophoblastic penetration into maternal vessels and the function of the trophoblast replacing the endothelium, feto-maternal junctional zone (FMJZ) removed from human uteri in early gestational stages of 4 to 11 weeks were morphologically investigated. The trophoblast cells which can approach to or penetrate the maternal vessels and can replace the endothelial cell were only syncytiotrophoblast cells. Since microfilaments aggregated in bundle in cytoplasm of the syncytiotrophoblast cells which are approaching to the maternal vessel inserted into dense bodies or dense patches, it is considered that the microfilaments are composed of thin filaments mainly like in smooth muscle cell. Degranulation of rER and lysosomal structure or aggregation of microfilaments are occurred in endothelial cells penetrated or closely contacted by field horsetail-like cytoplasmic processes of syncytiotrophoblast cell, respectively. It is possible that the syncytiotrophoblast cell and maternal endothelial cell have similar origin, since both cell can be in close contact with tight junction and simple apposition like intrinsic endothelial junction.

Blood Vessels↗
PubMed1981

Phagocytosis of human cytotrophoblast cell invading into decidual tissue in early stage of gestation.

To elucidate the mechanism of trophoblastic invasion, further electron microscopic observation of human implantation sites, described in a preliminary paper, were performed. The cytotrophoblast cells invaded decidual tissue have taken in many cells and absorbed many materials. In this paper, the authors specifically report the phagocytotic function of the cytotrophoblast cell. It was clarified by criteria, described in preliminary papers, for judgement of cells composing the feto-maternal junctional zone that almost all cells phagocytized by the cytotrophoblast cells were decidual cells which showed significant ultrastructural changes in various degrees; some cells still had intrinsic features by which the cells could be clearly identified as decidual cell, and some cells were considered as a strongly altered degenerated decidual cells. Moreover, even though these phagocytized cells had not so many lysosome that these cells can autolysis, the cytotrophoblast cells had many lysosome having strong activity of acid phosphatase. After the cytotrophoblast cells contact decidual cells by means of many patterns, the cytotrophoblast cells can phagocytized the inactivated cell and can intracytoplasmically digest the cell actively.

Decidua↗
PubMed1980

[Effect of anti-human alpha-fetoprotein serum on human endodermal sinus tumor transplanted in nude mice (author's transl)].

The effects of horse anti-human alpha-fetoprotein (AFP) immunoglobulin (IgG) on growth, serum AFP concentration and histopathology of human endodermal sinus tumor serially xeno-transplanted in nude mice were examined. Anti-AFP IgG given in amounts sufficient to neutralize the serum AFP secreted by the tumor moderately reduced tumor size and significantly decreased the serum AFP levels of treated nude mice. On histopathologic examination, spindle shaped tumor cells of reticular pattern often fell into the state of necrosis. But little change was observed on the cells consisting of both solid patterns and Schiller-Duval bodies. With a growth rate of re-transplanted tissues respectively, which were obtained from both antibody administrated and control tumors, no disparity was found between two groups. Indeed this result is preliminary report, but inhibitory effects of anti-AFP IgG against tumor growth and AFP producing ability of endodermal sinus tumor xeno-transplanted in nude mouse is hopeful to apply these data on clinical cancer immunochemotherapy.

Animals↗
PubMed1980

Production of steroids in one case of granulosa cell tumor in culture.

The cellular origin and the mechanism of steroidogenesis were investigated on one case of recurrent type of granulosa cell tumor. Light and electron microscopic findings indicated the cell component was non-luteinized granulosal element and neither fibroblastic nor thecal ones. These tumor cells were cultured as monolayers and steroids (estradiol-17 beta, dehydroepiandrosterone, progesterone and 17-hydroxyprogesterone) secreted in the medium were measured by radioimmunoassay. Despite low level of estrogen, progesterone or testosterone in the serum or urine preoperatively, the estradiol-17B level in the culture medium after three days of cultivation reached over 900 pg/ml. In both light and electron microscopic observations of the cultured cells, morphological characteristics of activation of steroidogenesis were noted. It is concluded that this type of granulosa cell tumor consisting exclusively of the granulosa element without thecal one has the activity of estrogen production.

Cells, Cultured↗
PubMed1980

Hetero-transplantation of human endometrial carcinoma into nude mouse. Effects of sex steroid hormones on morphological aspects of undifferentiated adenocarcinoma cells.

Seven cases of human endometrial carcinoma were transplanted into nude mice. Two of these cases, histologically classed as undifferentiated adenocarcinoma, were succeeded in the initial transplantation, but only 1, designated JEA-1, was established as serially transplanted tumor line in nude mice, which contained no estrogen and progesterone receptors assayed by sucrose density gradient centrifugation. JEA-1 tumor cells transplanted serially maintained the morphological and the functional characteristics of the original human tumor. Consequently, the JEA-1 tumor line will be useful for the experimental model of cancer treatments and the analysis of sensitivity for sex steroid hormones. Effects of sex steroid hormones on JEA-1 tumor cells had been examined and the electron microscopic observation and in receptor level, alteration of the tumor tissue were found. Ultrastructurally, the tumor cells which had been administrated estradiol and progesterone revealed various morphological changes resembling that of normal endometrial epithelium in the proliferative and the secretory phase, respectively. In addition, in the tumor tissue which had been administrated estradiol, the low, but positive, estrogen receptor sites were detectable. These findings may suggest that means of estradiol exposure will be able to induce the estrogen and progesterone receptors in endometrial carcinoma initially without these hormone receptors.

Adenocarcinoma↗
PubMed1979

Structural components of sphingophosphonolipids from the ciliated protozoan, Tetrahymena pyriformis WH-14.

1. Two sphingophosphonolipids were isolated from the lipids of the ciliated protozoan, Tetrahymena pyriformis WH-14. They were ceramide N-methyl-2-aminoethylphosphonate (CMAEP) and ceramide 2-aminoethylphosphonate (CAEP), in yields of 0.05 mg/g and 1.74 mg/g dry cells, respectively. 2. Two chromatographically distinguishable CAEP species were found, a slow-moving major component and a minor component which moved faster; the slow-moving one contained primarily hydroxy fatty acids, while in the other one nonhydroxy fatty acids were predominant. However, their long-chain base constituents were similar. 3. The major fatty acids of CAEP were 2-hydroxy acids with carbon numbers of 16 to 19, which were almost exclusively iso-types. The fatty acids of CMAEP consisted mainly of palmitic, iso-octadecanoic, and 2-hydroxy iso-heptadecanoic acids. 4. The long-chain bases were dominated by C16, C17, and C19 iso-4-sphingenine homologs.

Animals↗
PubMed1977

Clear cell carcinoma of the ovary: light and electron microscopic studies.

Twelve cases of ovarian clear cell carcinoma were studied histologically. Four cases were examined electron microscopically and compared with other conditions. Five tumors were directly connected with ovarian endometriosis. They were histologically classified into a tubular type with hobnail cells and a solid type without tubular pattern or hobnail cells. Electron microscopic figures of the tumor cells are identical having large nuclei, abundant glycogen, lamellated RER, few lipid droplets, and sparse but well-developed microvilli. The basophilic dark cells frequently encountered in the tubular type are morphologically quite similar to clear cells excepting for sparsity of glycogen and lipid droplets. Alveolar arrangement of 6 to 10 tubular structures (honeycomb structure) resembling alveolate structure seen in late secretory endometrium was found in tumor cells of one case. Ultrastructural feature of clear cell carcinoma closely resemble those of Arias-Stella endometrium and clear cell carcinoma of endocervix suggesting their Muellerian origin.

Adenocarcinoma↗
PubMed1976

The fine structural localization of peroxidase activity in goblet cells of the conjunctival epithelium of rats.

Cytochemical investigation of peroxidase was made on the conjunctival goblet cells, using the diaminobenzidine method. Many goblet cells in the conjunctiva demonstrated this reaction. The reaction was present in secretory granules as well as in the perinuclear cisterna, the rough endoplasmic reticulum, several Golgi saccules and adjacent small smooth-surfaced vesicles, and condensing vacuoles. Each secretory granule within a goblet cell showed a different degree of reaction, hence it is concluded that some goblet cells probably produce both mucous substance and peroxidase in one cell. The mode of production of peroxidase in goblet cells is concluded to be similar to that of secretory proteins in pancreatic exocrine cells. The enzyme, together with thiocyanate and endogenous hydrogen peroxide, is thought to serve as an anti-infectious agent in tears.

Amitrole↗
PubMed1976

2,7-Fluorenediamine and 2,5-fluorenediamine as peroxidase reagents for blood smears.

Our new histochemical methods for peroxidase activity, which do not require benzidine as a hydrogen donor, have been modified for hematological use. Diamine derivatives of fluorene (2,7-fluorenediamine and 2,5-fluorenediamine) were employed in place of benzidine and the result obtained was satisfactory. Two staining techniques were developed. (1) Smears of peripheral blood or bone marrow aspirates were fixed in 2.5 per cent glutaraldehyde solution for 1 minute. Smears were then washed in tap water and covered either by a saturated solution of 2,7-bluorenediamine or by a 0.05 per cent solution of 2,5-fluorenediamine in the presence of hydrogen peroxide for 5 minutes. After being washed in running tap water they were counterstained with Carazzi's hematoxylin solution for 10 minutes. (2) The second technique employs pretreatment of blood smears with 5 per cent CuSO4 solution and aldehyde fixation was omitted. Smears were counterstained by Giemsa stain. The nuclear chromatin structures were well preserved and nucleoli were easily distinguished in the immature cells. In the first method, clear brown granules were recognized in the cytoplasms. In the second method, peroxidase-positive granules were stained black and the staining of nucleus and cytoplasm resembled that of McJunkin's method.

Blood↗