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Biomedical subjects

H Satoh

Publications and source records attributed to H Satoh.

At least 847 records · Page 47Linked to original sources
PubMed1985

[Granulosa-cell growth factor in oocyte and its transport systems].

The possible existence of granulosa-cell growth factor (GGF) in the oocyte has been investigated using the labelling index (LI) with 3H-Thymidine and the mitotic index (MI) of granulosa cells (G-cells) in mice. The following results were obtained. In preantral follicles the LI increased with the development of the oocyte until its diameter reached the maximum (approximately 90 mu). In preantral follicles with the oocyte diameter below 69 mu, the LI was low and the follicular diameter was small. As the oocyte developed, the LI increased and reached the maximum value when the follicular diameter was approximately 200 mu. Then it decreased a little but maintained a high value. The antrum formation was seen when the follicular diameter was about 300 mu showing no change in LI. In preantral follicles with the oocyte diameter over 80 mu the G-cell near the oocyte had a much higher LI than the distant one. After the antrum formation, the LI and MI of cumulus layers adjacent to the oocyte were three times as great as those of the mural layers. Among the mural cell layers in the antral follicle the layer adjacent to the antrum showed remarkably high LI in comparison with the distant layers. These results suggest that GGF which seems to play a role in the formation of cumulus is secreted with the development of the oocyte. The GGF is transported through two systems the preantral follicle and cumulus layer through the G-cell gap junction and mural layers through the follicular fluid.

Animals↗
PubMed1985

Reversal of caffeine-induced calcium overload in cardiac Purkinje fibers.

In cardiac Purkinje fibers, caffeine initially increases and then decreases contractile force. The possible role of calcium overload in the negative inotropic effect of caffeine was studied in vitro under conditions that have been demonstrated to increase or decrease cellular calcium. The following results were obtained. Increasing [K]0 increased the initial positive and decreased the subsequent negative inotropic effect of 1 mM caffeine. At higher concentrations (2 and 4 mM), caffeine induced a larger negative inotropic effect which was reversed by high [K]0. Similarly, the positive inotropic effect was increased and the negative decreased by lowering [Ca]0. In high [Ca]0 or low [Na]0, caffeine had a predominantly negative inotropic effect which also was reversed by adding tetrodotoxin or by high [K]0. Reciprocally, in high [K]0, increasing [Ca]0 restored the negative inotropic effect of caffeine. During a brief exposure to zero [Ca]0, the force fell in the absence but less or not at all in the presence of caffeine. It is concluded that caffeine decreases contractile force in cardiac Purkinje fibers mostly by causing calcium overload.

Animals↗
PubMed1985

[On the effect of an oocyte factor on the formation of cumulus oophorus in human antral follicles].

The possible existence of a granulosa cell growth factor (GGF) in the oocyte was investigated by using the mitotic index (%) of granulosa cells (GC) in human antral follicles. 50 follicles (0.4-13 mm in diameter) in 35 ovaries obtained from 35 women were used for the experiments. In each follicle, GC were divided into two groups, cumulus and mural GC, according to the distance from the oocyte. The following results were obtained: The Mitotic Index (MI) of cumulus GC was 8.2 +/- 0.5 (M +/- SE) and was two fold higher than that of mural GC, 4.7 +/- 0.4 (p less than 0.001). As follicles developed, MI of mural GC increased until their diameter reached 3mm but beyond 3mm, MI decreased. On the other hand, there was little relationship between MI of cumulus GC and the follicular size, and MI was constantly high in value. MI of both cumulus and mural GC was higher in the late follicular phase than in other phases of the cycle. These results suggest that the proliferation of GC in growing follicle might be regulated by some unknown substance (GGF) secreted from the oocyte as well as the endocrinological environment. It is also suggested that the presence of the oocyte plays a crucial role in the cumulus oophorus formation in the antral follicles.

Adult↗
PubMed1985

Effects of 5-acetylspiro[benzofuran-2(3H),1'-cyclopropan]-3-one, a new anti-ulcer agent, on experimental acute and chronic ulcers.

The effects of 5-acetylspiro[benzofuran-2(3H),1'-cyclopropan]-3-one (AG 629), a newly synthesized compound, on various experimentally induced ulcers were investigated. Oral or intraduodenal administration of AG 629 in a dose range of 25-100 mg/kg inhibited water-immersion stress ulcer, exertion ulcer, Shay ulcer, indometacin- and acetylsalicylic acid (ASA)-induced gastric ulcer, and indomethacin-induced small intestinal ulcer in rats, histamine-induced gastric ulcer in guinea pigs, and ASA-induced gastric ulcer in dogs, though it was not effective against cysteamine-induced duodenal ulcer in rats. AG 629 in doses of 6.3-25 mg/kg p.o. twice a day significantly promoted the healing of acetic acid- or thermal-cortisone-induced gastric ulcers and acetic acid-induced duodenal ulcers in rats. AG 629 (25-100 mg/kg i.d.) inhibited the secretion of gastric acid and pepsin in pylorus-ligated rats and the acid secretion stimulated by distension of the rat stomach with air, whereas this compound did not affect acid secretion stimulated by histamine, pentagastrin, carbachol or 2-deoxy-D-glucose. This study shows that AG 629 has both prophylactic and curative effects on various ulcers. The anti-ulcer effect of this agent seems to be mediated primarily by increasing mucosal resistance and secondarily by an antisecretory activity.

Acetates↗
PubMed1984

Histologic grade and karyotype of immature teratoma of the ovary.

Seven cases of ovarian "pure" immature teratoma were encountered in patients 10 to 38 years of age, six cases being in Stage Ia and one case in Stage IIc. The primary tumors and recurrent growth observed in one case were histologically graded from 0 to 3 according to the criteria of Norris et al. Karyotypes of the tumors and the patients were determined using culture and banding techniques. The only nonsurviving case was in Stage IIc. Four primary tumors belonging to grades 0, 1, and 2 showed a normal 46,XX female karyotype and the patients are alive and healthy. Three grade 3 tumors showed various types of karyotype abnormalities (48,XX,+14,+21; 47,XX,+20; 47,XXX). One patient died, one is alive after experiencing a recurrent tumor, and one has only been followed for 22 months. All seven patients had a normal 46,XX female chromosome constitution. Evidence to date indicates that karyotype of ovarian immature teratoma is either normal female 46,XX or a slight deviation from normal. It is postulated that in ovarian immature teratoma normal 46,XX karyotype is an indicator of favorable prognosis, whereas deviations in karyotype suggest a possibility of poor prognosis.

Adolescent↗
PubMed1984

Prostacyclin-independence in beta-adrenoceptor mediated renin release from dog renal cortical slices.

There is some controversy regarding whether stimulation of renin release by the beta-adrenergic system is dependent on prostaglandin (PG) production. We have examined this problem in renal cortical slices of the dog and have obtained the following results: (1) Isoproterenol (4 X 10(-6) M) stimulated renin release, but had no effect on the formation of 6-keto PGF1 alpha, a stable metabolite of PGI2; (2) Indomethacin (2 X 10(-5) M) had no effect on isoproterenol stimulated renin release, but inhibited 6-keto PGF1 alpha formation; (3) Dibutyryl cyclic AMP (10(-3) M) stimulated both renin release, and 6-keto PGF1 alpha release. Indomethacin (2 X 10(-5) M) did not inhibit dibutyryl cyclic AMP-stimulated renin release, but did inhibit the production of 6 keto PGF1 alpha. These results indicate that the beta-adrenoceptor mediated renin release does not depend on the formation of PGI2, but renin release is dependent on cyclic AMP formation.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Effect of propafenone on the membrane currents of rabbit sino-atrial node cells.

The effects of propafenone (1-50 micrograms/ml) on the membrane potential and currents of the rabbit sino-atrial node were studied using the voltage clamp technique. Propafenone decreased the heart rate, amplitude of the action potential and maximum rate of depolarization. It also depolarized the maximum diastolic potential and the resting potential and prolonged the action potential duration dose dependently. On the current systems of the sino-atrial node, propafenone reduced the outward current (ik), the inward current activated by hyperpolarization (ih) and the slow inward current (is) dose dependently. The decrease in is and ik by propafenone was due to the reductions in their conductance, not to the changes in the voltage dependence of the inactivation of is or activation of ik. The decrease in ik might be the ionic mechanism of the negative chronotropic effect of propafenone.

Action Potentials↗
PubMed1984

Prostaglandin E2 and I2 production in isolated dog renal arteries in the absence or presence of vascular endothelial cells.

The spontaneous prostaglandin I2 production was significantly reduced by the removal of endothelial cells from the isolated dog renal arteries compared with relative slight reduction of prostaglandin E2 production. The stimulation of prostaglandin I2 production induced with angiotensin II was also markedly reduced under the absence of endothelial cells, while its potentiation of prostaglandin E2 production was not inhibited. The results suggest that the vascular endothelial cells are the major sources of prostaglandin I2 in the dog renal arteries, while prostaglandin E2 is mainly produced in other cell types, perhaps vascular smooth muscle cells.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Endothelial cell-dependent relaxation and contraction induced by histamine in the isolated guinea-pig pulmonary artery.

Histamine (10(-8)-10(-6) M) relaxed in a concentration-dependent manner the guinea-pig pulmonary artery which had been contracted by noradrenaline (5 X 10(-7) M). After the removal of endothelial cells (ETCs) histamine at the same concentrations did not cause relaxation but induced additional contraction. Both responses to histamine were antagonized by chlorpheniramine (3 X 10(-7) M). These results suggest that in the pulmonary artery histamine simultaneously stimulates H1-receptors located on both ETCs and smooth muscle cells. This results in two opposite effects, relaxation mediated by ETCs, and contraction.

Animals↗
PubMed1984

Normal organic and inorganic mercury levels in the human feto-placental system.

To clarify the normal metabolism of mercurials in the human feto-placental system, organic (or methyl) mercury and inorganic mercury were measured in maternal blood (MB), umbilical cord blood (UB), and chorionic tissues of the placenta (PC) and its blood vessels (PV), obtained from pregnant women just after delivery, as well as in fetal liver and fetal brain from induced abortion cases. Organic mercury was commonly detected in MB, UB, PC and PV, with slightly more elevated values in UB and PC than in MB, whereas inorganic mercury was detected in PC and PV, but not in MB and UB. In the fetal liver, 27-60% of mercury was in the form of inorganic mercury, whilst in four of five fetal brain samples, inorganic mercury was not detected. Additionally, fetal liver demethylation activity was studied in vitro. Incubation of methyl mercury with chopped fetal liver tissue for 24 h resulted in demethylation of approximately 1% of the methyl mercury.

Dealkylation↗
PubMed1984

Stimulation of gastric prostaglandin synthesis by refeeding in the rat. Role in protection of gastric mucosa from damage.

The purpose of the present study was to determine whether feeding stimulates prostaglandin (PG) synthesis in the gastric mucosa and whether this might play a role in the defensive mechanism of the gastric mucosa. The effect of refeeding on the formation of gastric lesions induced by nonsteroidal antiinflammatory drugs and on the generation of prostaglandin in the gastric mucosa was investigated. In the fasted rat aspirin and indomethacin produced many lesions in the corpus, but few or no lesions in the antrum. Refeeding of chow pellets before aspirin or indomethacin significantly decreased the corpus lesions, but provoked lesions in the antrum. When each drug was given before the refeeding, the protection against corpus lesions by refeeding was reduced and the lesions in the antrum were significantly increased. Mucosal generation of 6-keto-PGF 1 alpha (a stable metabolite of PGI2) and PGF2 alpha was measured ex vivo by the method of Whittle. The generation of 6-keto-PGF1 alpha and PGF2 alpha in the fasted rat deprived of food for 24 hr was 1761 +/- 170 and 217 +/- 7 ng/min/g tissue in the corpus mucosa, and 2958 +/- 217 and 453 +/- 33 ng/min/g tissue in the antral mucosa, respectively. Refeeding of chow pellets significantly increased the generation of both prostaglandins in the antral mucosa and of PGF2 alpha in the corpus mucosa, but did not affect the generation of PGI2 in the corpus mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Distinctive effect of angiotensin II on prostaglandin production in dog renal and femoral arteries.

The effect of angiotensin II (Ang II) on prostaglandin (PG) production in dog renal and femoral vasculature was examined in vivo and in vitro. In pentobarbital anesthetized dogs, the reduction of blood flow induced by intra-arterial infusion of Ang II was potentiated by pre-treatment with indomethacin (5 mg/kg) in the renal but not the femoral vasculature. Isolated renal and femoral arterial strips were incubated and the release of PGE2 and PGI2 (as 6-keto-PGF1 alpha) into the medium was measured by radioimmunoassay. Basal PGE2 and PGI2 production by renal and femoral arterial strips was approximately the same. PGI2 production was predominant for both strips. Ang II stimulated PG production in renal but not femoral arteries. In the renal artery, Ang II-induced PG production was inhibited by indomethacin (10(-6) M), mepacrine (10(-4) M) and saralasin (10(-6) M). These results suggest that Ang II stimulates PG production by the renal artery per se and the Ang II receptor is linked to phospholipase A2 in the renal but not the femoral artery.

6-Ketoprostaglandin F1 alpha↗