Biomedical subjects

S Fujii

Publications and source records attributed to S Fujii.

At least 469 records · Page 26Linked to original sources

PubMed1993

Effect of hypertension on arterial structure and wound repair at the microvascular anastomosis site using stroke-prone spontaneously hypertensive rats (SHRSP).

Different processes of microvascular wound healing under hypertension in comparison to normotension have been suspected. To explore these differences at the site of anastomotic wound repair, we performed microvascular anastomoses of the femoral arteries in 12-week-old, stroke-prone hypertensive rats (SHRSP) whose maximum blood pressure reached 238 mm Hg and in normotensive age-matched Wistar Kyoto (WKY) rats. Morphologic changes under hypertension were examined via light microscopy. The arrangement and number of endothelial cells were examined using the en face silver staining technique. The plasma activity levels of factor XIII were also measured in each group. Transitional healing at the microvascular anastomosis site was evaluated via scanning electron microscopy. The extent of endothelial migration over the exposed media around the needle holes was determined using a computerized graphic analysis system. Histologic cross sections demonstrated a thickened media, with altered shape and arrangement of the smooth muscle cell nuclei in SHRSP arteries compared with WKY arteries. En face silver staining showed small and spindle-shaped endothelial cells with an irregular cell arrangement and distribution in SHRSP arteries relative to WKY arteries. Factor XIII was increased 36% over baseline in SHRSP rats postoperatively; this was significantly higher than the increase in WKY rats (P < 0.05). Although both SHRSP and WKY arteries had similar wound healing responses to microvascular anastomosis, endothelial cell migration over the exposed media was significantly accelerated in the SHRSP rats.

Anastomosis, Surgical↗

PubMed1993

Dynamic changes in stress fiber expression in rat uterine vein endothelial cells associated with pregnancy.

En face endothelial preparations of rat uterine vein were stained with rhodamine-phalloidin to investigate the dynamics of stress fiber expression during pregnancy. In prepregnant animals, somewhat plump, spindle-like endothelial cells of the uterine vein had only a few short stress fibers. With the progress of pregnancy, however, many long stress fibers appeared within the elongated endothelial cells. Within 2 hr after delivery, these stress fibers became dramatically decreased in number as the cells reverted from an elongated to a plump shape and returned to the prepregnancy level by 14 days postpartum. The uterine vein showed a significant increase in length during pregnancy and quickly shortened after delivery. Thus, expression of stress fibers in endothelial cells of the uterine vein seems to be related to the tension loaded on this vessel during its elongation in parallel with the marked growth of the uterine body during pregnancy. This study shows that stress fibers are dynamic structures that may serve to maintain endothelial cell integrity during the exertion of tensile stress on the vessel wall.

Actins↗

PubMed1993

The number of proliferating cell nuclear antigen positive cells in endometriotic lesions differs from that in the endometrium. Analysis of PCNA positive cells during the menstrual cycle and in post-menopause.

Immunohistochemical expression of proliferating cell nuclear antigen (PCNA) was studied in the endometrium and in endometriotic lesions during the menstrual cycle and in post-menopausal patients. During the menstrual cycle, in the basal layer of the endometrium, an increase in the number of positive indices (PI) of PCNA was observed in epithelial cells from the menstrual phase. It reached a maximum in the proliferative phase and decreased in the secretory phase. However, no change was observed in the stromal cells of the basal layer. In the functional layer of the endometrium, the PI of the epithelial cells showed a high peak in the late proliferative phase, decreased sharply in the secretory phase and remained unchanged thereafter. The PI of the stromal cells in the functional layer showed two peaks, one in the late proliferative and the other in the mid and late secretory phase. In the endometriotic lesions, except for the proliferative phase, the number of PI was significantly higher than that of the corresponding endometrium and no significant changes were observed during the menstrual cycle. In post-menopausal endometriotic lesions, the number of PI was also higher than that of the corresponding endometrium. Thus the numbers of PI differed between the endometrium and endometriotic lesions in the same patients. These results imply that the endometriotic lesions are constantly more proliferative than the endometrium irrespective of the hormonal milieu during both the menstrual cycle and in a post-menopausal environment.

Adult↗

PubMed1993

Maternal serum CA125 levels in early intrauterine and tubal pregnancies.

Using an immunoradiometric assay, serum CA125 levels were measured in 13 women with a normal pregnancy, 9 with a spontaneous abortion, 3 with a hydatidiform mole, and 15 with a tubal pregnancy. Serum CA125 levels were high in patients with a normal pregnancy (154 +/- 169 U/ml; mean +/- S.D.), a spontaneous abortion (244 +/- 258 U/ml), or a hydatidiform mole (54 +/- 16 U/ml). In contrast, CA125 levels in patients with a tubal pregnancy (33 +/- 25 U/ml) were low, and almost all of those without uterine bleeding (25 +/- 9 U/ml) were within the normal range for non-pregnant women (< 35 U/ml). The difference between serum CA125 levels with intrauterine pregnancy and with tubal pregnancy may be ascribed to the difference of the amount of decidual tissues at the site of trophoblastic invasion.

Abortion, Spontaneous↗

PubMed1993

Role of marginal stress fibers formed in the rat vascular endothelial cells.

Fluorescence cytochemistry using en face preparations of rat vascular endothelial cells (ECs) revealed the localization of actin, fibronectin (FN) and fibronectin receptor (FNR) along not only central stress fibers (SFs) but also the cell margins. Electron microscopy showed very close proximity between the topographical distribution of intracellular microfilament bundles and that of subendothelial FN in the EC margins. Therefore, these basal and marginal actin cables may be comparable to the well-established central SFs present in ECs. Formation of the central SFs was induced in ECs or mesothelial cells in response to tension, by which their cellular integrity seems to be effectively maintained. However, even when central SF formation was inhibited by cytochalasin D, the ECs with marginal SFs showed high resistance to mechanical tension, whereas mesenteric mesothelial cells having no such fibers easily lost their integrity. Thus, together with central SFs, the marginal SFs characteristic of rat vascular ECs may play an essential role in strengthening cell-matrix adhesion.

Actins↗

PubMed1993

13C- and 15N-NMR studies on medium-chain acyl-CoA dehydrogenase reconstituted with 13C- and 15N-enriched flavin adenine dinucleotide.

The 13C- and 15N-NMR spectra of porcine kidney medium-chain acyl-CoA dehydrogenase (MCAD) reconstituted with 13C- and 15N-enriched FADs were measured. The positions of selective enrichment were C(2), C(4), C(4 alpha), C(10 alpha), N(1), N(3), and N(5) of the isoalloxazine nucleus of FAD. The NMR signals of the labeled atoms were observed as broad but distinct peaks in each NMR spectrum. The chemical shift values of the 2-, 4-, 4 alpha-, and 10 alpha-13C for the oxidized form of MCAD were 159.5, 166.8, 141.1, and 155.5 ppm, respectively, relative to the methyl resonance of 3-(trimethylsilyl)propionic acid-d4, while those of 1-, 3-, and 5-15N for the oxidized form were 183.6, 161.1, and 334.7 ppm, relative to liquid ammonia, respectively. The upfield shift of 2-13C of MCAD relative to that of FMN in the aqueous medium and its downfield shift relative to that of tetraacetylriboflavin in an apolar medium imply that a weaker hydrogen bond exists between C(2) = O and apoMCAD or a water molecule than that of free FMN with a water molecule. That the 4-13C resonance was observed downfield-shifted relative to that of free FMN in aqueous solution suggests a strong hydrogen bond between C(4) = O and apoMCAD. The chemical shift for 4 alpha-13C in oxidized MCAD is considerably downfield-shifted from that of FMN or any other flavoprotein observed thus far, indicating a unique environment around this position in MCAD. The 1-15N resonance of MCAD was most upfield-shifted among the flavoproteins observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Acyl Coenzyme A↗

PubMed1993

Hydrolysis of micellar diheptanoylphosphatidylcholine catalyzed by bovine pancreatic phospholipase A2: kinetic characterization of group I and II enzymes.

Initial velocity data for the hydrolysis of micellar 1,2-diheptanoyl-sn-glycero-3-phosphorylcholine (diC7PC) catalyzed by bovine pancreatic PLA2 (Group I) were analyzed using the Michaelis-Menten equation. The Km value for the micellar substrate was found to be independent of Ca2+ concentration, as was the Km value for the monodispersed substrate. The pH dependence curve of Km in the presence of saturating amounts of Ca2+ showed two transitions reflecting large pK shifts of two ionizable groups from 5.0 to 5.45 and from 9.5 to 10.25, whereas the Km value for the monodispersed substrate was independent of pH [Fujii et al. (1991) J. Biochem. 110, 1008-1015]. The pH dependence curve of kcat showed three transitions, indicating the participation of three ionizable groups with pK values of 5.45, 8.4, and 10.25. Deprotonation of the first group and protonation of the third group were found to be essential for catalysis. The respective groups were assigned as the catalytic group His 48, the N-terminal alpha-amino group, and invariant Tyr 52. The present results as well as those for another Group I PLA2 (Naja naja atra) are very different from those for Group II PLA2s (Agkistrodon halys blomhoffii and Trimeresurus flavoviridis), which showed Ca(2+)-dependent substrate binding and no participation of the alpha-amino group in catalysis [Teshima et al. (1989) J. Biochem. 106, 518-527; Nishimura et al. (1992) J. Biochem. 111, 210-218].(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Crystallization and preliminary X-ray study of Agkistrodon halys blomhoffii phospholipase A2 complexed with a specific inhibitor.

Phospholipase A2 from the venom of Agkistrodon halys blomhoffii has been crystallized as a complex with a specific inhibitor, (S)-2-dodecanoyl-amino-3-hexanol-1-phosphoglycol. The complex crystals belong to the hexagonal space group, P6(1)22 (or P6(5)22), with cell dimensions of a = b = 61.13 A, and c = 173.15 A. The diffraction extends to at least 2.3 A resolution.

Animals↗

PubMed1993

Molecular dynamics simulation of 1,2-dilauroyl-L-phosphatidylethanolamine binding to phospholipase A2: an attempt to explain the selective hydrolysis of substrate fatty acid ester at position 2.

To improve our understanding of why phospholipase A2 (PLA2) specifically catalyzes the hydrolysis of the fatty acid ester bond at position 2, not at position 1, of 1,2-diacyl-3-sn-phosphoglycerides, the binding of each fatty acid chain of 1,2-dilauroyl-L-phosphatidyl-ethanolamine (DLPE), a natural substrate, to bovine pancreas PLA2 was examined by molecular dynamics (MD) simulations. Two different binding modes were considered, i.e., the respective hydrocarbon chains of 1- and 2-lauroyl fatty acid esters were located at the PLA2 binding sites usually observed in the complex crystals (Form A2) and at the reverse sites (Form A1). Although the total energies of both forms fluctuated within nearly the same range during the 80 ps MD simulations, the binding mode of DLPE to the PLA2 catalytic site through the coordination to Ca2+ was much more advantageous in Form A2 than that in Form A1; significant deviation of the Ca2+ position from its starting structure was observed in the MD simulation of Form A1. The result suggests the importance of Ca2+ in the selective recognition and catalytic function of PLA2 toward the 2-positioned fatty acid ester of phosphoglyceride substrates.

Animals↗

PubMed1993

Characterization of the electron acceptors of old yellow enzyme: mechanistic approach to the mode of one electron transfer from the enzyme to menadione or dyestuffs.

Molecular oxygen or cytochrome c has been described as the electron acceptor of the reaction of old yellow enzyme with NADPH. In this study, menadione was found to be a sensitive electron acceptor of the reaction under aerobic as well as anaerobic conditions. The Km value of menadione for old yellow enzyme is as low as 2-3 x 10(-7) M in the presence or absence of superoxide dismutase. The rate enhancement of the cytochrome c reduction of old yellow enzyme with NADPH was about eight times in the presence of menadione. The rate increment was slightly higher under aerobic than anaerobic conditions. The rate enhancement by menadione enabled sensitive determination of the enzyme activity in the assay system, which contained NADPH, cytochrome c, menadione, and old yellow enzyme. In the reaction course, the semiquinone species of menadione was trapped by the reaction with t-butyl-alpha-phenylnitrone. The radical adduct was detected on EPR. The dyestuff, 2,6-dichlorophenolindophenol, was found to be reduced ineffectively even in the presence of menadione; moreover, it was inhibitory in the NADPH consumption reaction. Methylene blue or Lauth's violet, known to be capable of semiquinone formation, also behaved, like menadione, as a mediator of electron transport to cytochrome c. On the basis of the experimental results, the occurrence of the one electron transfer of the old yellow enzyme reaction was emphasized.

2,6-Dichloroindophenol↗

PubMed1993

Successful pregnancy in a woman with premature ovarian failure.

A case of a patient with premature ovarian failure (POF) is discussed. Ovulation failed to occur for 5 years by gonadotropin-releasing hormone agonist (GnRHa) and human menopausal gonadotropin (hMG) treatment following estrogen-progesterone replacement therapy. After laparoscopic ovarian biopsy, ovulation was successfully induced by hMG, although gonadotropins were not suppressed enough, and the patient achieved pregnancy.

Adult↗

PubMed1993

Basolateral membrane Cl- and K+ conductances of the dark-adapted chick retinal pigment epithelium.

1. We characterized the basolateral membrane Cl- and K+ conductances of the dark-adapted chick neural retina-retinal pigment epithelium (RPE)-choroid preparation. Conventional microelectrodes were used to measure apical (V(ap)) and basolateral (Vba) membrane voltage, and double-barreled Cl- and K+ selective microelectrodes were used to follow the time course and magnitude of ion concentration changes outside the basolateral (basal) membrane. 2. In response to a fivefold decrease in basal [Cl-]o, Vba rapidly depolarized by 6.4 +/- 0.7 (SE) mV, and the apparent resistance of the basolateral membrane (Rba) increased. The Cl- channel blocker 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS) suppressed the Vba depolarization by 40% and blocked the Rba increase. Estimates of the relative Cl- conductance (transference number, TCl) from the DIDS-sensitive component of the Cl- diffusion potential gave an average value for TCl of 0.22 +/- 0.03. 3. Further evidence for a Cl- conductance was obtained by measuring changes in intracellular Cl- activity (aCli) induced by transtissue current. Depolarizing Vba elevated aiCl, whereas hyperpolarizing Vba had the opposite effect, consistent with conductive Cl- movement across the basal membrane. TCl estimated from these data averaged 0.23 +/- 0.02. 4. In response to a sixfold increase in basal [K+]o, Vba depolarized 6.1 +/- 0.8 mV. The amplitude of this K+ diffusion potential was inhibited 44 and 67% by 5 and 10 mM Ba2+, respectively. TK was estimated to be 0.61 +/- 0.05. 5. The rapid c-wave membrane hyperpolarizations in response to the light-evoked decrease in subretinal [K+]o were used to calculate the equivalent resistances of the apical membrane (R(ap)), basolateral membrane (Rba), and the paracellular shunt pathway (Rs). They were 152 +/- 10, 615 +/- 38, and 138 +/- 7 omega.cm2 (n = 11 tissues), respectively. From these data the equivalent electromotive force for the basal (Eba) and apical (Eap) membranes were estimated to be -45 +/- 2 and -77 +/- 1 mV, respectively. This estimate of Eba is in the range of that predicted from our estimates of TCl and TK, indicating that, in the dark-adapted chick retina, the resting conductance of the basal membrane can largely be accounted for by the Cl- and K+ conductances described here.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed1993

Induction of vascular smooth muscle cell expression of plasminogen activator inhibitor-1 by thrombin.

Local accumulation of plasminogen activator inhibitor-1 (PAI-1) in response to thrombosis has been implicated not only in inhibition of fibrinolysis but also in the pathogenesis of vascular disease. To determine whether thrombin, known to be released from thrombi, can induce expression of PAI-1 in vascular smooth muscle, bovine aortic smooth muscle cells were exposed to highly purified bovine thrombin. Thrombin, in the absence of serum, induced production of PAI-1 by bovine aortic smooth muscle cells in a dose-dependent manner. PAI-1 activity in the conditioned media reached a maximum with 12 nM thrombin. Metabolic labeling with [35S]methionine demonstrated that the elaborated PAI-1 was newly synthesized and that it comprised both a cleaved inactive 42-kd form and an uncleaved active 46-kd form. The increase of PAI-1 activity in the media paralleled the thrombin-induced increase in the concentration of the 46-kd form. Preincubation of thrombin with hirudin, a specific inhibitor of thrombin, or with D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone, an inhibitor of the active site of thrombin, prevented the induction of PAI-1 synthesis. The stimulatory effect of thrombin on PAI-1 synthesis was also evident at the level of expression of mRNA, with steady-state PAI-1 mRNA levels increasing by 100% in 4-8 hours. When the bovine aortic smooth muscle cells were exposed to transforming growth factor-beta 1, an agonist shown previously to increase PAI-1 synthesis in diverse cell types, synergy with thrombin was evident.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Potentiation by hypercholesterolemia of the induction of aortic intramural synthesis of plasminogen activator inhibitor type 1 by endothelial injury.

Accumulation of plasminogen activator inhibitor type 1 (PAI-1) in the arterial wall may accelerate atherogenesis by inhibiting fibrinolysis, diminishing proteolysis of extracellular matrix proteins, or modifying migration of vascular smooth muscle cells. Increased intramural expression of the PAI-1 gene is induced by thrombosis. To determine whether it occurs also in response to a sustained mechanical insult to endothelium, hypercholesterolemia, or both, rabbits were subjected to sustained aortic injury induced by implantation of indwelling polyethylene tubing, to hyperlipidemia induced by cholesterol and peanut oil feeding over a period of 8 weeks, or both. Sustained vascular injury alone did not increase plasma PAI-1. However, hypercholesterolemia with or without mechanically induced vascular injury increased plasma PAI-1 twofold. The expression of PAI-1 mRNA in aorta (Northern blots) was significantly increased when vascular injury was combined with hyperlipidemia. In situ hybridization showed that the increase with mechanical injury alone occurred in endothelial cells covering the neointima (positive for factor VIII and thrombomodulin), in abnormally differentiated vascular smooth muscle cells (positive for embryonic myosin heavy chain), and in macrophages (positive for the RAM-11 anti-macrophage antibody). Qualitatively similar but much more marked increases in PAI-1 gene expression were seen when arterial injury was accompanied by hypercholesterolemia. Neither vitronectin, known to stabilize PAI-1, nor vitronectin mRNA increased in liver. However, immunocytochemistry and Western blots demonstrated marked aortic accumulation of vitronectin protein with hyperlipidemia, particularly in subendothelial fibrotic regions, accompanied by increased neointimal vitronectin mRNA as shown by in situ hybridization. These results suggest that increased synthesis and stabilization of vascular PAI-1 may potentiate accumulation of extracellular matrix, thereby accelerating atherosclerosis.

Animals↗

PubMed1993

Synthesis and structure-activity study of protease inhibitors. V. Chemical modification of 6-amidino-2-naphthyl 4-guanidinobenzoate.

By developing 6-amidino-2-naphthyl 4-guanidinobenzoate (I, FUT-175) as a basic structure, its various derivatives were synthesized and their inhibitory activities on trypsin, plasmin, kallikrein, thrombin, C1r and C1s as well as on complement-mediated hemolysis were examined. The protective effect of these compounds on complement-mediated Forssman shock was also examined in guinea pigs. 6-Amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl)amino]-benzoate (41, FUT-187) was found to be a suitable compound for oral administration with anti-complement activity superior to that of compound I.

Animals↗

PubMed1993

Usefulness of a simplified artificial insemination technique in the rabbit for teratology studies.

We describe usefulness of our simplified artificial insemination technique in rabbits for teratology studies. Our technique includes 1) semen collection from 2 or 3 bucks with a simple artificial vagina, 2) deposition of 0.5 microliters of the diluted semen mixture in the vagina with a glass pipette, and 3) injection of 25 U. of hCG through the auricular vein. Applying these techniques and procedures and keeping about 10 proven bucks would enable 2 operators to inseminate 10-15 does daily by only 1 hour work. This artificial insemination technique should be useful for rabbit teratology studies, especially for safety evaluation studies of toxicants, where a relatively large number of pregnant are needed to be prepared in a short period.

Animals↗

PubMed1993

Anthracycline metabolites from baumycin-producing Streptomyces sp. D788. II. New anthracycline metabolites produced by a blocked mutant strain RPM-5.

A daunorubicin-blocked mutant strain RPM-5 derived from a new baumycin-producing Streptomyces sp. D788 accumulated a major precursor metabolite D788-1 (10-carboxyl-13-deoxocarminomycin) and nine minor metabolites in the culture broth. Five among them were new with a substituent at C-10 or the altered side chains at C-9. Isolation, purification and identification of all anthracycline metabolites produced by strain RPM-5 are described with their antitumor activities against L1210 cells.

Animals↗

PubMed1993

Model building program HLX4: application to non-classical helical structures.

The model building program HLX4 for multiple stranded helices was developed as a useful tool for understanding of the biological roles of these helices and application of nobel base pairing scheme by chemical modification. In stead of torsion angle, the helical parameter is elected as the input information to generate the starting global structure. The model building performance is threefold, first, coarse connectivity check and second, fine connectivity check and energy minimization. This program system can be successfully applied to the DNA duplex with the nobel G:A base pairing and triplex with the modified sugar moiety.

Base Sequence↗