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S Takemori

Publications and source records attributed to S Takemori.

At least 55 records · Page 3Linked to original sources
PubMed1993

X-ray diffraction study on mammalian visceral smooth muscles in resting and activated states.

Structural changes of guinea pig taenia coli and rat anococcygeus muscle during contraction were studied by X-ray diffraction. The diffraction pattern of the taenia coli showed the 14.4-nm myosin reflection, the 5.9-nm actin layer-line and a diffuse equatorial peak at 1/11.4 nm-1. On application of carbachol, the muscle contracted and the intensity of the 14.4-nm reflection showed a concentration-dependent decrease: the maximum decrease was 24% at 2 x 10(-5) M. Such an intensity decrease was not observed in K-contracture (154 mM). The intensity of the 5.9-nm actin layer-line did not change appreciably on activation. The equatorial peak became broader during contraction. The 14.4-nm myosin reflection of the anococcygeus muscle was weak. Its intensity increased by 106% during contraction induced by 2 x 10(-5) M phenylephrine and by 75% during K-contracture. These results suggest that the number of myosin filaments may increase during contraction of rat anococcygeus muscle but not guinea pig taenia coli.

Animals↗
PubMed1993

Immunohistochemical localization of 17 alpha-hydroxylase/C17-20 lyase and aromatase cytochrome P-450 in polycystic human ovaries.

Immunohistochemical localization of 17 alpha-hydroxylase/C17-20 lyase (P-450(17 alpha,lyase)) and aromatase cytochrome P-450 (P-450arom) in polycystic ovary (PCO) syndrome was studied using specific polyclonal antibodies which had been raised against the corresponding enzymes. In the majority of follicles that were atretic and smaller than 7 mm in diameter, theca interna cells showed high P-450(17 alpha,lyase) immunoreaction, while small numbers of granulosa cells showed little P-450arom immunoreaction. In some atretic follicles that were larger than 11 mm in diameter, the hyperplastic theca interna cell layer showed high immunoreaction to P-450(17 alpha,lyase), while the poorly proliferated granulosa cell layer showed a mixture of weak and negative immunoreaction to P-450arom. No immunoreaction to P-450(17 alpha,lyase) or P-450arom was recognized in PCO stroma. These findings suggest that the theca interna cells and the granulosa cells from PCOs show abnormal steroidogenic function, while the localization of P-450(17 alpha,lyase) and P-450arom in PCOs was essentially identical to that in the normal ovary. Theca interna cells in PCO atretic follicles are the main site of excess androgen production.

Adult↗
PubMed1993

Delayed post-anoxic encephalopathy without relation to carbon monoxide poisoning.

Delayed post-anoxic encephalopathy (DPE) not related to carbon monoxide has rarely been reported and usually carries a poor prognosis. We describe two surviving patients with such DPE and its neuro-otological characteristics. The DPE was caused by shock due to hemorrhage in a 21-year-old student, and by severe hypoxia and hypotension in a 60-year-old man. Our findings suggest that this type of DPE might not be rare, if the patients who suffered from severe anoxia, marked hypotension or both are carefully observed. Recognition of this DPE is important for appropriate management of such patients.

Adult↗
PubMed1993

[Clinicopathological evaluation of high-range hyperthermia for advanced thoracic esophageal carcinoma].

The effectiveness of high-range hyperthermia over 45 degrees C for advanced esophageal carcinoma was clinicopathologically evaluated. Fifty-eight patients with advanced thoracic esophageal carcinoma were treated with radio-chemotherapy. They were divided into two groups: group I included 32 cases, all of whom received hyperthermia (13 cases: high-range hyperthermia); group II included the other 26 cases. The patients were given 2 Gy/day for a total of 15 sessions in 3 weeks. Bleomycin and cisplatin in combination with 5-fluorouracil have been employed as chemotherapy. Hyperthermia was performed twice a week for a total of 6 sessions. Intraluminal heating was done using Japan Crescent Inc. IH-500 T (RF, 13.56 MHz), with an intraesophageal applicator and two extra-corporeal applicators on the chest and the back. Concerning local effects, the efficacy rate was 81.3% in group I (high-range: 92.9%), and 42.3% in group II. The histologic effectiveness, when Grade 2 and 3 are determined as histologically effective, were 64.3% (high range: 85.7%) and 50.0% in group I and II, respectively.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Inhibitory effects of 20 alpha-hydroxyprogesterone on steroid hydroxylation reactions of guinea pig adrenal microsomes.

Using guinea pig adrenal microsomes, we studied the inhibitory effects of 20 alpha-hydroxyprogesterone on steroid hydroxylation reactions catalyzed by cytochromes P-450. When 17 alpha-hydroxyprogesterone was used as a substrate, 20 alpha-hydroxyprogesterone functioned as a competitive inhibitor on the C17-C20 bond cleavage reaction of P-450(17)alpha lyase. The inhibition constant, Ki was 1.37 mumol/L. 20 alpha-hydroxyprogesterone also competitively inhibited the conversion of 17 alpha-hydroxyprogesterone to 11-deoxycortisol by the action of P-450c21. The value of Ki was 1.73 mumol/L. When progesterone was used as a substrate, 20 alpha-hydroxyprogesterone inhibited neither the 21-hydroxylation of P-450c21, the C17-C20 bond cleavage, nor 17 alpha-hydroxylation of P-450(17)alpha lyase. Based on these results, we can deduce that the production of androstenedione from progesterone by the action of P-450(17)alpha lyase proceeds through a successive monooxygenase reaction.

17-alpha-Hydroxyprogesterone↗
PubMed1993

[Experimental study on comparative efficacy of hepatic arterial injection of anticancer agent under temporary occlusion of portal vein].

To compare the efficacy of intra-hepatic arterial infusion of anti-cancer drug under temporary occlusion of portal vein, the following two experiments were performed. 1. VX2 tumor cells (about 1 x 10(5) cells) were transplanted through the superior mesenteric vein of the rabbits, after 2 weeks, 4'-0-Tetrahydropyranyl doxorubicin (2 mg/kg, 2 ml) aqueous solution (THP) was administered into hepatic artery of rabbits with metastatic VX2 liver tumor. 2. THP was injected into hepatic artery under temporary occlusion of portal branch of median left lobe with metastatic liver. Then the THP levels of normal liver tissue and tumor of median left lobe and lateral right lobe. The THP levels of tumor under portal occlusion tended to be about 2.63-fold higher than without occlusion. These results suggest that hepatic arterial injection under portal occlusion is more useful to increase the levels of anticancer agents of metastatic liver tumor.

Animals↗
PubMed1992

Dynamic structures of adrenocortical cytochrome P-450 in proteoliposomes and microsomes: protein rotation study.

Purified adrenocortical microsomal cytochromes P-45017 alpha,lyase and P-450C21 were reconstituted with and without NADPH-cytochrome P-450 reductase in phosphatidylcholine-phosphatidylethanolamine-phosphatidylserine vesicles at a lipid to P-450 ratio of 35 (w/w) by cholate dialysis procedures. Trypsinolysis revealed that a considerable part of each P-450 molecule is deeply embedded in the lipid bilayer, on the basis of the observation of no detectable digestion for P-45017 alpha,lyase and the proteolysis-resistant membrane-bound heavy fragments for P-450C21. Rotational diffusion was measured in proteoliposomes and adrenocortical microsomes by observing the decay of absorption anisotropy, r(t), after photolysis of the heme-CO complex. Analysis of r(t) was based on a "rotation-about-membrane normal" model. The absorption anisotropy decayed within 1-2 ms to a time-independent value r3. Coexistence of a mobile population with an average rotational relaxation time phi of 138-577 microseconds and immobile (phi > or = 20 ms) populations of cytochrome P-450 was observed in both phospholipid vesicles and microsomes. Different tilt angles of the heme plane from the membrane plane were determined in proteoliposomes to be either 47 degrees or 63 degrees for P-45017 alpha,lyase from [r3/r(0)]min = 0.04 and either 38 degrees or 78 degrees for P-450C21 from [r3/r(0)]min = 0.19, when these P-450s were completely mobilized by incubation with 730 mM NaCl. Very different interactions with the reductase have been observed for the two P-450s in proteoliposomes. In the presence of the reductase, the mobile population of cytochrome P-450C21 was increased significantly from 79% to 96% due to dissociation of P-450 oligomers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex↗
PubMed1992

Kinetic studies on androstenedione production in ovarian microsomes from immature rats.

Androstenedione formation from progesterone by P-450(17 alpha,lyase) was investigated in ovarian microsomes of immature rats treated with pregnant mare serum gonadotropin. Successive monooxygenase reactions in the formation of androstenedione without the intermediate leaving P-450(17 alpha,lyase) were demonstrated by a double-substrate double-label experiment using [14C]progesterone and 17 alpha-[3H]hydroxyprogesterone as substrates and also by specific reduction in the concentration of intermediate 17 alpha-hydroxyprogesterone in the reaction medium by reaction of liposomal P-450C21. A detailed kinetic study on the reactions of P-450(17 alpha,lyase) in microsomes was conducted in the steady state. Kinetic parameters indicated the C17,C20-lyase reaction for 17 alpha-hydroxyprogesterone (Km = 80 nM) to be strongly inhibited by progesterone (Ki = 8 nM). In the presence of a high concentration of progesterone, as in the case of in vivo rat ovary, most androstenedione is concluded to be formed directly from progesterone by successive monooxygenase reactions catalyzed by P-450(17 alpha,lyase). 20 alpha-Dihydroprogesterone competitively inhibited the C17,C20-lyase reaction for 17 alpha-hydroxyprogesterone with Ki = 23 nM, but had only slight effect on progesterone metabolism to androstenedione. 20 alpha-Dihydroprogesterone, thus, cannot be a regulator for androstenedione formation in rat ovary.

Androstenedione↗
PubMed1992

Cytochrome P-450(17 alpha,lyase)-mediating pathway of androgen synthesis in bovine adrenocortical cultured cells.

Cytochrome P-450(17 alpha,lyase) mediating pathway of dehydroepiandrosterone (DHA) formation from pregnenolone was investigated in primary cultures of bovine adrenocortical fasciculata-reticularis cells. To determine whether DHA formation proceeds predominantly by successive monooxygenase reactions without 17 alpha-hydroxypregnenolone leaving P-450(17 alpha,lyase) the cells were incubated with [14C]pregnenolone and 17 alpha-[3H]hydroxypregnenolone in the presence of Trilostane. Results of the double-substrate double-label experiments indicate that in the presence of high concentration of pregnenolone most of DHA was formed, directly from pregnenolone by the successive reactions. Since the concentration of pregnenolone usually exceeds that of 17 alpha-hydroxypregnenolone in the adrenal glands, DHA is concluded to be formed predominantly by successive reactions from pregnenolone without 17 alpha-hydroxypregnenolone leaving P-450(17 alpha,lyase) in vivo. By chronic ACTH treatment, the activities of 17 alpha-hydroxylation and DHA formation in adrenocortical cultured cells became higher concomitantly with the increase of P-450(17 alpha,lyase) content. Most of DHA was found to be formed by successive reactions from pregnenolone even under such conditions.

Adrenal Cortex↗
PubMed1992

Adrenal P-450scc modulates activity of P-45011 beta in liposomal and mitochondrial membranes. Implication of P-450scc in zone specificity of aldosterone biosynthesis in bovine adrenal.

Bovine adrenal P-45011 beta catalyzes the 11 beta- and 18-hydroxylation of corticosteroids as well as aldosterone synthesis. These activities of P-45011 beta were found to be modulated by another mitochondrial cytochrome P-450 species, P-450scc. The presence together of P-45011 beta and P-450scc in liposomal membranes was found to remarkably stimulate the 11 beta-hydroxylase activity of P-45011 beta and also stimulate the cholesterol desmolase activity of P-450scc. The stimulative effect of P-450scc on 11 beta-hydroxylase activity diminished by the addition of protein-free liposomes to proteoliposomes containing P-45011 beta and P-450scc, thus showing P-450scc to interact with P-45011 beta in the same membranes. Kinetic analysis of this effect indicated the formation of an equimolar complex between P-45011 beta and P-450scc on liposomal membranes. P-45011 beta in the complex had not only stimulated activity for 11 beta- and 18-hydroxylation of 11-deoxycorticosterone but also suppressed activity for production of 18-hydroxycorticosterone and aldosterone. When the inner mitochondrial membranes of zona fasciculata-reticularis from bovine adrenal were treated with anti-P-450scc IgG, aldosterone formation was stimulated to a greater extent than that of zona glomerulosa. This indicates the aldosterone synthesizing activity of P-45011 beta in the zona fasciculata-reticularis to be suppressed by interaction with P-450scc. The zone-specific aldosterone synthesis of P-45011 beta in bovine adrenal may possibly be induced by differences in interactions with P-450scc of mitochondrial membranes in each zone.

Adrenal Cortex↗
PubMed1992

Effects of 2,3-butanedione monoxime on contraction of frog skeletal muscles: an X-ray diffraction study.

We studied the effects of BDM (2,3-butanedione monoxime) on the tetanic contraction of frog skeletal muscles using an X-ray diffraction technique. BDM significantly increased the resting equatorial intensity ratio (I1,0/I1,1). In sartorius muscle, 3 mM BDM suppressed tetanic tension by 40-70% whereas the equatorial intensity ratio, which is 2.6 at rest, decreased to 0.75 during tetanus, close to the value in normal contraction (about 0.50). BDM (3 mM) reduced the intensity increase of the 5.1-nm layer-line to 41%, that of the 5.9-nm layer-line to 24%, and the intensity decrease of the second myosin meridional reflection (at 1/21.5 nm-1) at 81%. In overstretched semitendinosus muscle, 3 mM BDM did not significantly reduce the intensity increase of the second actin layer-line during activation, suggesting that enough calcium is released to activate the regulatory system and the regulatory proteins are intact. These results indicate that BDM suppresses tetanic tension by mainly inhibiting actin-myosin interaction. It has a smaller effect on the equatorial reflections and myosin layer-lines than on the actin layer-lines, suggesting that BDM-influenced myosin heads may bind to actin without following the symmetry of the actin helix.

Actin Cytoskeleton↗
PubMed1992

The role of cytochrome b5 in adrenal microsomal steroidogenesis.

The role of cytochrome b5 in adrenal microsomal steroidogenesis was studied in guinea pig adrenal microsomes and also in the liposomal system containing purified cytochrome P-450s and NADPH-cytochrome P-450 reductase. Preincubation of the microsomes with anti-cytochrome b5 immunoglobulin decreased both 17 alpha- and 21-hydroxylase activity in the microsomes. In liposomes containing NADPH-cytochrome P-450 reductase and P-450C21 or P-450(17) alpha,lyase, addition of a small amount of cytochrome b5 stimulated the hydroxylase activity while a large amount of cytochrome b5 suppressed the hydroxylase activity. The effect of cytochrome b5 on the rates of the first electron transfer to P-450C21 in liposome membranes was determined from stopped flow measurements and that of the second electron transfer was estimated from the oxygenated difference spectra in the steady state. It was indicated that a small amount of cytochrome b5 activated the hydroxylase activity by supplying additional second electrons to oxygenated P-450C21 in the liposomes while a large amount of cytochrome b5 might suppress the activity through the interferences in the interaction between the reductase and P-450C21.

Adrenal Cortex Hormones↗
PubMed1992

Destruction of testicular cytochrome P-450 by 7 alpha-thiospironolactone is catalyzed by the 17 alpha-hydroxylase.

Studies were done to determine the role of the 17 alpha-hydroxylase in the conversion of 7 alpha-thiospironolactone (7 alpha-thio-SL) to a reactive metabolite causing the degradation of testicular cytochrome P-450. Incubation of guinea pig testicular microsomes with 7 alpha-thio-SL plus NADPH resulted in an approx. 70% decline in cytochrome P-450 content and even greater loss of 17 alpha-hydroxylase activity. Addition of the 17 alpha-hydroxylase inhibitor, SU-10'603, to the incubation medium prevented the degradation of P-450 by 7 alpha-thio-SL. Similarly, preincubation of testicular microsomes with anti-P-45017 alpha,lyase IgG to inhibit 17 alpha-hydroxylation, diminished the subsequent loss of P-450 caused by 7 alpha-thio-SL. The results indicate that the 17 alpha-hydroxylase catalyzes the conversion of 7 alpha-thio-SL to the reactive metabolite responsible for P-450 destruction. The accompanying loss of 17 alpha-hydroxylase activity supports the hypothesis that suicide inhibition is the mechanism involved.

Animals↗
PubMed1992

Immunohistochemical localization of 17 alpha-hydroxylase/C17-20 lyase and aromatase cytochrome P-450 in the human ovary during the menstrual cycle.

Immunohistochemical localization of 17 alpha-hydroxylase/C17-20 lyase (P-450(17 alpha,lyase)) and aromatase cytochrome P-450 (P-450arom) in normal human ovaries during the menstrual cycle was studied using specific polyclonal antibodies which were raised against corresponding enzymes. In the follicular phase of matured follicles, P-450(17 alpha,lyase) was localized in theca interna cells and P-450arom in granulosa cells. P-450(17 alpha,lyase) was expressed in theca interna cells before P-450arom was expressed in granulosa cells. The corpus luteum showed immunoreactivity to both enzymes and, after menstruation, immunoreactivity decreased gradually until it could not be detected in the corpus albicans. In corpus luteum graviditatis the immunoreactivity continued to be expressed strongly. In some atretic follicles, P-450(17 alpha,lyase) and/or P-450arom continued to be expressed. In the stromal layer, P-450(17 alpha,lyase was detected in secondary interstitial cells, which originated from the theca interna of atretic follicles, and P-450arom was detected in hilar cells. Immunoreactivity to both enzymes was also detected in oocytes of developing follicles. These results are consistent with the two cell theory in the human ovary. They also suggest that androgens and oestrogens are produced not only by follicles and corpora lutea but also by stroma and oocytes.

Adult↗
PubMed1992

Immunohistochemical studies on the localization of aromatase and 17 alpha-hydroxylase/C17-20 lyase (17 alpha-lyase) in estrous cycling and pregnant hamster ovaries.

In order to clarify periodic changes in the localization of enzymes engaged in estrogen biosynthesis during the estrous cycle, immunohistochemical and fine structural studies were performed using estrous cycling and pregnant hamster ovaries. Results showed that ovulation takes place at midnight between Day 4 and Day 1 in the regular 4 day-cycle hamster. Immunoreactivity for aromatase is localized in the granulosa cells of the secondary follicle and granulosa lutein cells during the morning (10:00 am) of Day 1 to the evening (5:00 pm) of Day 4; in the night (9:00 pm) of Day 4, only the granulosa cells of the Graafian follicle showed a strong immunoreaction. As for 17 alpha-lyase, theca interna cells of the secondary follicle are immunopositive throughout Day 2 to the morning (10:00 am) of Day 4. Only a few cells in the theca interna of the Graafian follicles are immunopositive in the evening (5:00 pm) of Day 4. No positive cells for this enzyme were detected in the night (9:00 pm) of Day 4 or morning (10:00 am) of Day 1. The rapid decrease of estrogen biosynthesis occurring just before ovulation is considered to be due to the disappearance of 17 alpha-lyase in the theca interna cells of the ovary. On Day 10 of pregnancy, the granulosa cells of the secondary follicles and both the granulosa and theca lutein cells of the corpora lutea are immunostained with the aromatase antibody, while the theca interna cells of the secondary follicles reacted positively to the 17 alpha-lyase antibody. Only the granulosa and theca interna cells from the large preovulatory Graafian follicle of Day 4 (proestrus) which are positively stained for aromatase as well as 17 alpha-lyase show ultrastructural features typical of steroid secretory cells.

Aldehyde-Lyases↗
PubMed1992

[Hyperthermia for cancer with dextran magnetite using tubular implants].

Dextran magnetite particles (Meito Sangyo Corp.) are an aqueous magnetite zol and a nanometer complex consisting of dextran chains surrounding a core of ultrafine iron oxide. The tubular implants were made with polyester tube (3 mm diameter, 20 mm length) filled with DM aqueous zol (29%w/v). The temperature of an agar phantom with implants was measured in the inductive field. Heating was effected by creating an electromagnetic field with a 7 kW generator operating at 500kHz (Yamamoto Vinyter). The temperature was elevated 3.4 degrees at a distance of 5 mm from the implant at an inductive power of 2.6 kW. An area of 20 x 20 mm was heated while changing the power, the number of implants, and their arrangement. Selective heating of cancer was considered possible by inductive heating at 500 kHz and DM implants. Since the DM aqueous zol configuration can be readily changed, treatment of various cancers is possible.

Dextrans↗
PubMed1991

Kinetic control of steroidogenesis by steroid concentration in guinea pig adrenal microsomes.

For clarification of the effects of steroid concentration on steroidogenesis of adrenal microsomes, the kinetic parameters, Km and kcat, were determined in the steady-state for progesterone and 17 alpha-hydroxyprogesterone metabolism catalyzed by P-450C21 and P-450(17 alpha lyase) in guinea pig adrenal microsomes. At a high concentration of progesterone, it was equally metabolized by P-450C21 and P-450(17 alpha lyase), while at a low concentration, it was hydroxylated at 17 alpha-position with twice higher rate than at 21-position. 17 alpha-Hydroxyprogesterone is apparently metabolized preferentially by P-450C21 at any concentration. Although the productions of deoxycortisol and androstenedione from 17 alpha-hydroxyprogesterone were strongly inhibited by progesterone, androstenedione formation from progesterone was not inhibited by a high concentration of progesterone. The addition of liposomal P-450C21 to the reaction medium containing adrenal microsomes caused a decrease in the concentration of 17 alpha-hydroxyprogesterone released into the medium in the steady state reaction, but this had no effect on the activity of androstenedione formation from high concentrations of progesterone. It thus follows that androstenedione is produced by successive monooxygenase reactions without the release of 17 alpha-hydroxyprogesterone from P-450(17 alpha lyase) at a high concentration of progesterone, which is the condition of the adrenal microsomes in vivo.

17-alpha-Hydroxyprogesterone↗