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Biomedical subjects

Y Okuda

Publications and source records attributed to Y Okuda.

At least 397 records · Page 22Linked to original sources
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↗
PubMed1981

[Scanning electron microscopic observations of microcorrosion casts for rabbit ovarian vasculature before ovulatory stimulus (author's transl)].

Ovarian vasculature of juvenile and adult rabbits was studied using a method of resin injection-corrosion casts. Arteries and arterioles in the ovarian stroma and capillary networks surrounding the follicles were observed on a three dimensional scale by scanning electron microscopy with the following findings: 1) The strongly coiled arteries are observed in adult rabbit ovaries. The first order arterioles arise from the spiral artery, and the second order arterioles stemming from these first order arterioles enter into each follicle. 2) Vasculature of follicles starts as glove-finger-like ramified capillary networks. As follicles grow, follicular vessels increase remarkably and form multilayered complex vascular networks surrounding the follicles. 3) The observations of circular impressions around the arterioles near the follicle and in the follicular wall suggest the existence of sphincteric control mechanism of blood flow into the follicle. 4) There are several pathways of venous drainage from a wall of large follicle and arterio-venous shunts are observed in the wall of such follicles. These structures may exert an important effect upon the follicular hemodynamics in the process of follicle rupture.

Animals↗
PubMed1981

[Histological studies of multiple subperitoneal nodules produced by prolonged administration of estrogen (author's transl)].

It has been reported that multiple peritoneal fibroids were produced in guinea pigs treated with large doses of estrogens, and the nodules regressed when the steroid stimulant was discontinued. Recently, these experimental nodules were considered to be simulating the disseminated pattern of Leiomyomatosis Peritonealis Disseminata (LPD). Although these experimental nodules were considered to be composed of fibroblasts by light-microscopic studies, LPD was verified to be composed of smooth muscle by electronmicroscopic studies. Therefore, it is indispensable to study these experimental nodules by electronmicroscopy, when we discuss about the similarities between experimental nodules and LPD. Guinea pigs were treated with various doses of estradiol benzoate (E) [40, 80, 100, 200 microgram/day, thrice a week, intramuscular injection]. After treatment for three months, every dose of E produced the lesions simulating the disseminated pattern of LPD: multiple nodules in various sizes, scattered on the surface of the uterine horn, peritoneum, spleen and pancreas, and in the omentum and mesocolon. Ultrastructurally, the nodules were composed of the cells resembling fibroblast. We conjectured that estrogen differentiates and proliferates the cells of the features of fibroblast-like cells from subcoelomic mesenchyme, resulting in the production of multiple superitoneal nodules simulating the disseminated pattern of LPD.

Animals↗
PubMed1981

[Ultrastructural observation of the ovulatory changes in the capillary of the human follicular apex (author's transl)].

To clarify its possible participation and mode of action in follicle rupture at human ovulation, the capillary in the apex of the ovarian follicle was investigated electronmicroscopically with 16 human ovaries. In the follicle at the mid-proliferative phase with 6 mm diameter, capillary lumen was narrow and empty. Capillary vessels observed in the theca interna of the preovulatory follicle were dilated and filled with blood cells. Their endothelial cells had indented nuclei and elongated thin cytoplasm with unusually irregular membranous protrusions. In cytoplasm there were numerous vesicles, some of which had fine granule-like contents of low electron density to be released into extracapillary space. These results indicate increased capillary permeability due to active transport around the time of ovulation. Polymorphonuclear leucocytes, rich in specific granules containing collagenase activity, were often observed in the capillary lumen as well as extracapillary space only close to the time of ovulation. This observation implies possible roles of leucocytes in collagen degradation. The present ultrastructural results suggest that the vast capillary network in the follicle wall plays an important role in the mechanism of follicle rupture through its increased permeability and collagenolytic activities of leucocytes.

Adult↗
PubMed1981

[Effects of inflammation and stimulant diets on functions of autonomic nervous system (author's transl)].

In usual medical consultation, we have been met a lot of female patients suffering from disturbances of autonomic nervous system such as headache, shoulder-ache and so on. Experiments were designed to elucidate whether or not these disturbances of autonomic nervous system were induced by inflammation and accelerated by stimulant diets. Functions of autonomic nervous system were examined by lipolysis in rat epididymal adipose tissue which was partly controlled by sympathetic nervous system. It was found that free fatty acid release from the epididymal adipose tissue was considerably elevated by inflammation which was formed in abdominal wall or in abdominal cavity or oral administration of stimulant diets such as red pepper and white pepper, and that such elevation of lipolysis was significantly reduced by resection of the autonomic nerve. These results indicated that the inflammation and the stimulant diets induced excitement of sympathetic nerve which controlled the epididymal adipose tissue. Experiments were now in progress to clarify relationship between such excitement of sympathetic nervous system induced by the inflammation or by the stimulant diet and irregular complaints due to disturbances of autonomic nervous system.

Adipose Tissue↗
PubMed1980

Effect of low concentrations of halothane on the oxygen electrode.

The effect of low concentrations of halothane dissolved in saline (equivalent to 0.34% halothane) on the oxygen electrode was examined using a multi-wire Clark type electrode, consisting of eight platinum wires, each of 15 microns tip diameter. On the first exposure of the day to saline equilibrated with halothane in 10% oxygen or air, the output of the oxygen electrode increased by 40% over 56 min. On the second and subsequent exposures the increase in output was much less, but was still 10% greater than the correct values. After immersing the electrode overnight in saline without halothane the high sensitivity to halothane was present again next morning, even if neither membrane nor electrolyte was changed.

Blood Gas Analysis↗
PubMed1980

[Cytochemical demonstration of 3 beta-hydroxysteroid dehydrogenase activity in human corpora lutea (author's transl)].

3 beta-hydroxysteroid dehydrogenase (3 beta-HDS) activity was demonstrated ultrastructurally in human corpora lutea obtained from the women aged 32-46 who were treated by the hysterectomy for various gynecological indications. The corpora lutea were removed from ovaries and cut into small pieces of 1 mm3. Specimens were incubated at 25 degrees C for 20 min. in the media containing dehydroepiandrosterone 0.6 mg, 0.1 M sodium citrate 0.3 ml, 5 mM potassium ferricyanide 1 ml, 30 mM copper sulfate 1 ml, N.A.D. 3.6 mg, sucrose 1.0 g and 0.1 M phosphate buffer (pH 7.2) 6 ml. For a control study, 1.5 mg cyanoketone (by the courtesy of Dr G.O. Pott), the specific inhibitor for 3 beta-HSD, was added to the media. The materials were fixed in 4% glutaraldhyde and 1% OsO4 and embedded in Epon 812. Electron dense reaction products of copper ferrocyanide were observed in smooth endoplasmic reticulum (sER) and in intercristal and outer space of mitochondria. In control studies, 3 beta-HSD activity were completely abolished. It is concluded that not only sER but also mitochondria has 3 beta-HSD activity in human corpora lutea. Furthermore, mitochondria seems to have capability to synthetize progesterone from cholesterol by itself.

3-Hydroxysteroid Dehydrogenases↗
PubMed1980

[An ultrastructural study of primary carcinoma of the fallopian tube (author's transl)].

Primary carcinoma of the fallopian tube is one of the least common neoplasms arising from the female genital tract with rare preoperative correct diagnosis. Recently, we had chances to experience two cases of this tumor, one of which was examined electron microscopically. Both of them revealed the well-differentiated pattern of papillary adenocarcinoma. Electron microscopically, most of the cancer cells had pleomorphic nuclei, giant or multiple nucleoli, numerous mitochondria, poorly developed rER and abundant polysomes. Small number of cells rich in lysosome-like granules were also observed near the basement membrane. Among the cancer cells, "ultrastructural alveolar spaces", composed of several cancer cells, were prominent. In the cancer cells, there were observed the following interesting observations; annulate lamellae-like structure, unusual bundles of the filamentous elements and lamellar body-like structures. Normal tubal epithelium consisted of ciliated cells, secretory cells, peg cells and so-called "indifferent cells". The fact that the present tumor had no ciliated cells and few secretory cells indicated that this tumor was originated from "indifferent cells" or peg cells.

Adenocarcinoma, Papillary↗
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↗
PubMed1980

[An ultrastructural study of capillaries of rabbit ovarian follicles during ovulatory process (author's transl)].

The observations that perifollicular capillaries of the ovary become engorged with prominent edema in the theca interna and externa around the time of ovulation, suggest a preovulatory increase in permeability of perifollicular capillaries. In order to obtain an ultrastructural evidence for this increased capillary permeability, we examined the perifollicular capillaries in the theca interna by using mature rabbit ovaries at various time intervals after the hCG injection for induction of ovulation. We observed a capillary engorgement at 9, 10, 12 hours after the hCG injection, most prominent at 9 hours, and edema in the pericapillary space at 10, 12 hours. Pinocytotic vesicles were seen through the all stages of follicular development and they did not show any significant changes in their size, number and distribution. Fenestrations were observed at 0, 3, 4, 6 hours after the hCG injection, most frequent at 4 hours. Intercellular gaps (500 approximately 1,200 A) between two endothelial cells were demonstrated at 10, 12 hours, and thrombocytes in these gaps were also noticed. The present observations suggest that increased permeability of perifollicular capillaries just prior to ovulation were mainly due to the formation of gaps between the endothelial cells.

Animals↗
PubMed1980

[An ultrastructural study of capillary permeability of rabbit ovarian follicles during ovulation using carbon tracer (author's transl)].

The observations that perifollicular capillaries of the ovary become engorged with prominent edema in the theca interna and externa around the time of ovulation, suggest a preovulatory increase in permeability of perifollicular capillaries. In previous study, we reported ultrastructural evidences which suggested the increased permeability of perifollicular capillaries just prior to ovulation. In this study, we further examined the perifollicular capillaries of rabbit ovary by using carbon particles as a tracer at various time intervals after the hCG injection for induction of ovulation. Pinocytotic vesicles exhibited no significant changes in size, number and distribution through all preovulatory stages. Carbon particles were not taken into them. Fenestrations were observed at 0,3,4,6 hrs after the hCG injection, most frequently at 4 hrs, but no carbon particles could penetrate them. Intercellular gaps between two adjacent endothelial cells began to be observed at 10 hrs after the hCG injection. Carbon particles passed through these gaps with staying inside the basement membrane (so-called intramural leaking). These observations indicated that the increased permeability of the perifollicular capillaries, just before ovulation, were due to intercellular gaps.

Animals↗
PubMed1979

Relationship between cerebral blood flow changes and cortical extracellular fluid pH during cerebral metabolic depression induced by althesin.

Baboons anaesthetized with halothane and nitrous oxide in oxygen were given Althesin 0.05 ml kg-1 i.v. Cerebral blood flow (c.b.f.) was measured by an electromagnetic flowmeter and by xenon clearance whilst extracellular fluid (e.c.f.) pH of the parietal cortex was measured with a micro pH electrode. Carotid blood flow (carBF) began to decrease and carotid vascular resistance (carVR) to increase 2.0 s (SEM 0.3) after the slowing of the e.e.g. produced by Althesin, while e.c.f. pH began to change to alkaline 10.5 s (SEM 1.0) after the e.e.g. change. The first statistically significant increase in mean e.c.f. pH occurred 25 s after the Althesin-induced change in the e.e.g. The duration of the changes in carVR and e.c.f. pH were 7 and 5 min respectively. It is concluded that the change in e.c.f. pH cannot have initiated the increase in carVR which followed the cerebral matabolic depression produced by Althesin. The later alkaline shift in e.c.f. pH may, however, have maintained the increased carVR during the duration of cerebral metabolic depression produced by Althesin.

Alfaxalone Alfadolone Mixture↗