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Biomedical subjects

S Fujii

Publications and source records attributed to S Fujii.

At least 649 records · Page 36Linked to original sources
PubMed1988

Electrophoretic determination of fructose 6-phosphate,2-kinase.

An electrophoretic determination of fructose 6-phosphate,2-kinase activity has been devised. The enzymes partially purified from bovine liver and heart were subjected to polyacrylamide gel electrophoresis and the production of fructose 2,6-bisphosphate, coupled to the activation of potato PPi:phosphofructokinase, was detected as the dark band due to the disappearance of the fluorescence evoked by NADH consumption. The enzyme from bovine heart showed slower electrophoretic mobility than that from bovine liver, strongly suggesting the possibility that they may be distinct enzyme forms. Rat liver enzyme also gave a mobility different from that of both bovine liver and heart enzymes. Our present procedure will provide a new tool for understanding fructose-6-phosphate,2-kinase/fructose 2,6-bisphosphatase system in various tissues.

Animals↗
PubMed1988

High expression of an N-acetylglucosaminyltransferase III in 3'-methyl DAB-induced hepatoma and ascites hepatoma.

Ascites hepatoma AH-66 and 3'-Me-DAB-induced hepatoma of rats contain highly active N-acetylglucosaminyltransferase III (GnT-III) which catalyzes the addition of N-acetylglucosamine through a beta 1-4 linkage (bisecting N-acetylglucosamine) to the beta-linked mannose of the trimannosyl core of asparagine-linked sugar chains, whereas normal rat liver contains very little. The high activity was also detected in fetal rat liver, newborn rat liver, hyperplastic nodules and various transplantable hepatomas.

Aging↗
PubMed1988

Hybrid hexanucleotide duplex containing cyclonucleotides and deoxynucleotides: the d(TA) segment can adopt a high anti left-handed double-helical structure.

It is known that oligonucleotides containing cyclonucleosides with a high anti (intermediate between anti and syn) glycosidic conformation adopt left-handed, single- and double-helical structures [Uesugi, S., Yano, J., Yano, E., & Ikehara, M. (1977) J. Am. Chem. Soc. 99, 2313-2323]. In order to see whether DNA can adopt the high anti left-handed double-helical structure or not, a self-complementary hexanucleotide containing 6,2'-O-cyclocytidine (C(o)), 8,2'-O-cycloguanosine (G(o)), thymidine, and deoxyadenosine, C(o)G(o)dTdAC(o)G(o), was synthesized. Imino proton NMR spectra and the results of nuclear Overhauser effect experiments strongly suggest that C(o)G(o)dTdAC(o)G(o) adopts a left-handed double-helical structure where the deoxynucleoside residues are involved in hydrogen bonding and take a high anti glycosidic conformation. A conformational model of the left-handed duplex was obtained by calculation with energy minimization. Thus it appears that DNA can form a high anti, left-handed double helix under some constrained conditions, which is quite different from that of Z-DNA.

DNA↗
PubMed1988

Diacylglycerol acyltransferase in maturing safflower seeds: its influences on the fatty acid composition of triacylglycerol and on the rate of triacylglycerol synthesis.

Diacylglycerol acyltransferase in a particulate preparation from maturing safflower seeds showed no strict selectivity for acyl-CoA when acyl-CoA substrates were administered as mixtures. This suggested that the fatty acid composition of position 3 in safflower triacyl-sn-glycerol exclusively depends on the acyl-CoA composition in the cell. The specific activity of the acylation was approximately 3 nmol/min per mg protein of the preparation under the optimum assay conditions. This low activity and other data appeared to indicate that the diacylglycerol acyltransferase reaction may be the rate-limiting step in triacylglycerol synthesis in vivo.

Acyltransferases↗
PubMed1988

Role of actin filaments in shape formation of mesenteric mesothelial cells of the bullfrog.

The role of actin filaments in the development of cellular shape in the mesenteric mesothelium of the bullfrog was studied by using a simple, new technique for making en face preparations of mesothelial sheets. By using these mesothelial cell preparations, the distribution of actin was determined by means of fluorescence microscopy with 7-nitrobenz-2-oxa-1,3-diazole (NBD)-phallacidin and that of myosin by means of immunofluorescence microscopy. Although fluorescence produced by both NBD-phallacidin and antimyosin staining was found exclusively along the margins of the cells, its intensity was altered in correspondence with changes in cell shape. For instance, tadpole-type mesothelial cells with either an irregular or very slender cell shape showed very weak fluorescence. On the other hand, frog-type mesothelial cells with a polygonal shape showed intense fluorescence at their margins and had circumferential bundles of actin filaments at their apices. Furthermore, intercellular junctions between the mesothelial cells developed as the cell shape became polygonal during metamorphosis. The present study showed that development of circumferential bundles of actin filaments and intercellular junctions may serve to establish and maintain the definitive polygonal cellular pattern in the mesenteric mesothelium of the bullfrog.

Actins↗
PubMed1988

Human erythrocyte sorbitol metabolism and the role of sorbitol dehydrogenase.

Rapid fluctuation of erythrocyte sorbitol in response to the changes in plasma glucose concentration has been reported from clinical evidence. We performed more extensive in vitro and in vivo studies focussing on how fast sorbitol was accumulated and how fast the accumulated sorbitol was oxidised in response to the changes in ambient glucose concentration. Incubation studies of intact erythrocytes from healthy subjects and diabetic patients showed that erythrocyte sorbitol increased rapidly in response to increased ambient glucose concentration and the accumulated sorbitol easily decreased according to the rapid reduction of ambient glucose concentration. In addition, the higher the glucose concentration in the medium, the more erythrocytes could accumulate sorbitol. The rapid response of sorbitol levels to ambient glucose concentration was further confirmed by the results of a 75 g oral glucose tolerance test in non-diabetic subjects and diabetic patients with gastrectomy, who showed marked early hyperglycaemia caused by rapid absorption of ingested glucose and subsequent rapid reduction of plasma glucose concentration (erythrocyte sorbitol levels changed concomitantly). These findings strongly indicate that the measurement of erythrocyte sorbitol is not useful as an index of medium or long term glycaemic control.

Adult↗
PubMed1988

Development of the fast sodium current in early embryonic chick heart cells.

Single ventricle cells were dissociated from the hearts of two-, three-, four- or seven-day-old chick embryos, and were maintained in vitro for an additional 6 to 28 hr. Rounded 13 to 18 micron cells with input capacitance of 5 to 10 pF were selected for analysis of fast sodium current (INa). Voltage command protocols designed to investigate the magnitude, voltage dependence, and kinetics of INa were applied with patch electrodes in the whole-cell clamp configuration. INa was present in over half of the 2d, and all 3d, 4d and 7d cells selected. The current showed no systematic differences in activation kinetics, voltage dependence, or tetrodotoxin (TTX) sensitivity with age or culture conditions. Between the 2d and 7d stages, the rate of current inactivation doubled and channel density increased about eightfold. At all stages tested, INa was blocked by TTX at a half-effective concentration of 0.5 to 1.0 nM. We conclude that the lack of Na dependence of the action potential upstroke on the second day of development results from the relatively depolarized level of the diastolic potential, and failure to activate the small available excitatory Na current. The change from Ca to Na dependence of the upstroke during the third to the seventh day of incubation results partly from the negative shift of the diastolic potential during this period, and in part from the increase in available Na conductance.

Action Potentials↗
PubMed1988

Development of cardiac beat rate in early chick embryos is regulated by regional cues.

The mesoderm of each of the paired lateral heart-forming regions (HFRs) in the stage 5-7 chick embryo includes prospective conus (pre-C), ventricle (pre-V), and sinoatrial (pre-SA) cells, arranged in a rostrocaudal sequence (C-V-SA). With microsurgery we divided each HFR into three rostrocaudally arranged segments. After 24 hr of further incubation, each segment differentiated into a spontaneously beating vesicle of heart tissue to form a multiheart embryo. The cardiac vesicles in these embryos expressed left-right and rostrocaudal beat rate gradients: the left caudal pre-SA mesoderm produced tissue with the fastest beat rate of the six while the rostral vesicle formed from right pre-C was the slowest. In another operation, we prevented the HFRs from fusing in the midline by cutting through the anterior intestinal portal at stage 8, to produce cardia bifida (CB) embryos with an independently beating half-heart on each side. In these cases, the left half-heart of 87.2% of CB embryos beat faster than the right, confirming the left-right difference in intrinsic beat rate. To assess whether the future beat rate of each region is already determined in the st 5-7 HFR, we exchanged rectangular fragments of left pre-SA mesoderm and attached endoderm with right pre-C fragments to yield a left HFR with the sequence C-V-C and a right HFR with the sequence SA-V-SA. A CB operation was subsequently performed on these exchange embryos to prevent fusion of the lateral HFRs. Preconus mesoderm, transplanted to the pre-SA region, differentiated into tissue with a rapid beat rate, while pre-SA mesoderm relocated to the preconus region formed heart tissue with a slow spontaneous rate typical of the conus. In 73% of the exchange CB embryos, the left half-heart beat faster than the right, despite the origins of its mesoderm. The exchanged mesoderm developed a rate that was appropriate for its new location rather than the site of origin of the mesodermal fragment. In a third set of operations, we implanted a fragment of st 15 differentiated conus tissue into a site lateral to the left caudal HFR in st 5, 6, and 7 embryos, and subsequently performed CB operations on them. The implant caused the adjacent half-heart to develop with a slower beat rate than in unoperated or sham-operated controls.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

Production of 19-oic-11-deoxycorticosterone from 19-oxo-11-deoxycorticosterone by cytochrome P-450(11)beta and nonenzymatic production of 19-nor-11-deoxycorticosterone from 19-oic-11-deoxycorticosterone.

19-Oxo-11-deoxycorticosterone was incubated with a cytochrome P-450(11)beta-reconstituted system, and the metabolites were analyzed by high performance liquid chromatography(HPLC). The main product found after chromatography was collected and treated with diazomethane. HPLC and 1H-NMR analysis of the methylated derivative indicated that it was 19-oic-11-deoxycorticosterone methyl ester. When 19-oic-11-deoxycorticosterone was stored at -20 degrees C for 1 month, it was spontaneously converted to other steroids. Structural analysis of the main degradation product indicated that it was 19-nor-11-deoxycorticosterone. These results suggest that the conversion of 19-oxo-11-deoxycorticosterone to 19-oic-11-deoxycorticosterone occurs through the P-450(11)beta-catalyzed reaction, and that the 19-oic-11-deoxycorticosterone thus formed is nonenzymatically converted into 19-nor-11-deoxycorticosterone.

Adrenal Cortex↗
PubMed1988

Vitamin B12 R-binder localization in the human uterus: an immunohistochemical study.

The localization of vitamin B12 R-binder in the uterus was studied by use of an immunoperoxidase technique. Positive staining by anti-R-binder antiserum was observed in the columnar epithelium of the endocervix (18/18 cases) and in the surface epithelium of the endometrium (8/21 cases). Staining was usually seen in the apical portion of the epithelium; cytoplasmic staining in the endocervical columnar epithelium was intense. The secretory products in the endocervical glands showed positive staining. The endometrial glandular epithelium did not stain (0/24 cases). Metaplastic squamous epithelium of the endocervix showed positive staining (3/18 cases). The native squamous epithelium as well as the stromal components of the cervix, endometrium, and myometrium were negative for R-binder. This study shows that R-binder is localized in the uterus, especially in the endocervical glands. The R-binder in the endocervix may have antimicrobial activity in the uterus as in other organs, such as the intestines and mammary glands.

Adult↗
PubMed1988

Fatty acid binding protein of cardiac muscle in spontaneously hypertensive rats: effect of hypertrophy and its regression.

To investigate the relationship between cardiac hypertrophy associated with hypertension, and the alterations in myocardial lipid metabolism, nicardipine (160 mg/kg/day), hydralazine (40 mg/kg/day), and enalapril (30 mg/kg/day) were administered to spontaneously hypertensive rats from 20 to 24 weeks of age. Drug administration significantly suppressed the increases in blood pressure and the ratio of left ventricular weight to body weight. A marked variation in the fatty acid binding capacities of the delipidated, dealbuminated heart cytosol obtained from these animals was observed in the 24-week-old rats (5.40 +/- 0.31 pmol/micrograms protein in non-treated rats; 4.73 +/- 0.34 pmol/mg protein in nicardipine-treated rats; 5.01 +/- 0.34 pmol/mg protein in hydralazine-treated rats; 4.61 +/- 0.26 pmol/mg protein in enalapril-treated rats) as compared to the 20-week-old non-treated rats (3.38 +/- 0.29 pmol/mg protein). The decrease in this capacity in the drug-treated groups closely correlated with the reduction of cardiac mass, suggesting that the factors governing regression may be closely related to those governing fatty acid binding capacity. It appears that fatty acid binding protein may play an important role in the hypertension-associated hypertrophic myocardium.

Animals↗
PubMed1988

Glucagon secretion in anorexia nervosa.

Patients with anorexia nervosa frequently manifest impaired glucose tolerance. However, alterations in pancreatic glucagon secretion have also been associated with alterations in diabetes mellitus. For this reason, pancreatic alpha- and beta-cell responses to glucose load were measured in 25 anorexic patients both before and after treatment. The baseline glucose challenge failed to suppress plasma glucagon levels in the patients. However, in the control subjects and patients after treatment, glucagon levels were suppressed after glucose ingestion. Plasma glucose levels during the baseline challenge were significantly higher than those of the control subjects; however, after treatment glucose responses were nearly normal. Finally, insulin responses at baseline and after treatment were lower in the patients than in control subjects. These results suggest that the impaired glucose tolerance manifested by anorexic patients may be attributable to significant alterations in both pancreatic alpha- and beta-cell secretions and in pancreatic alpha-cell and glucose interrelationships.

Analysis of Variance↗
PubMed1988

Ovarian mucinous cystadenocarcinoma producing alpha-fetoprotein.

Common epithelial ovarian tumors associated with alpha-fetoprotein (AFP) production are rare. A case of ovarian mucinous cystadenocarcinoma producing both AFP and carcinoembryonic antigen (CEA) is presented. A 53-year-old postmenopausal woman with right adnexal tumor underwent total hysterectomy and right salpingo-oophorectomy. Preoperative serum CEA and AFP levels were elevated to 660 and 1,120 ng/ml, respectively, and both decreased to their normal ranges after surgery. Histologically, the right ovarian tumor was diagnosed as a mucinous cystadenocarcinoma, composed of both intestinal-type cells and endocervical-type cells. Intestinal-type cells were identified ultrastructurally, with cells resembling neuroendocrine cells as well as gobletlike cells with many mucinous granules. Yolk sac or teratomatous components were not identified. By the immunoperoxidase technique, CEA was positive in well to moderately differentiated mucinous cells lining lumina, whereas AFP-positive cells were intermingled with CEA-positive cells in moderately differentiated epithelia.

Biomarkers, Tumor↗
PubMed1988

Increased renal fatty acid binding protein in spontaneously hypertensive rats.

The level of renal fatty acid binding protein (FABP) was quantified by a specific radial immunodiffusion method using an antibody to cytosolic FABP in stroke-prone spontaneously hypertensive rats (SHRSP) and normotensive Wistar-Kyoto rats (WKY) at 5, 10, 20 and 40 weeks of age. Increased levels were found in the SHRSP medulla, but not in the WKY medulla. The increase occurred in the hypertension development period, reaching a peak at 20 weeks of age. This increase was confirmed by immunoblotting. There was no significant change of FABP in the cortex. To elucidate the mechanism responsible for these changes in the FABP level, three antihypertensive drugs (nicardipine, hydralazine and enalapril) were given to SHRSP at 20 weeks of age for a period of four weeks. Antihypertensive treatment significantly inhibited the development of hypertension and the increase in the medullary FABP level. The differential response of FABP in SHRSP and WKY suggests that this protein may play an important role in the cellular metabolism of fatty acids under the pathological condition of high blood pressure.

Animals↗
PubMed1988

Adenomyosis: diagnosis with MR imaging.

Magnetic resonance (MR) imaging characteristics of adenomyosis were studied in eight women (aged 37-49 years) who underwent hysterectomy, and detailed radiologic/pathologic correlation was conducted in all cases. Adenomyosis produced diffuse and smooth uterine enlargement. The extent of the lesion was clearly identified on images obtained with long repetition time and long echo time; a diffuse, low-intensity area accompanied by tiny high-intensity spots was seen subjacent to the endometrium. The area appeared as a localized or diffuse thickening of the junctional zone because it was often isointense with this zone. Pathologic examination confirmed that the extent of adenomyosis correlated well with the low-intensity region on MR images and that both hemorrhagic areas and nonbleeding endometrial tissue corresponded to the high-intensity spots. The lesion consisted of distorted and compacted smooth muscle cells, but microscopic studies failed to explain the definitive difference in intensity between areas of adenomyosis and myometrium.

Adult↗