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  • 1990-1994  (23)
  • Life and Medical Sciences  (19)
  • Myocardial ischemia  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Effects of prostacyclin analogue, OP-2507, on function and metabolism in the ischemic working rat heart (1992)
    Springer
    Journal of anesthesia 6 (1992), S. 446-454 
    Details
    ISSN: 1438-8359
    Keywords: Myocardial ischemia ; Myocardial metabolism ; Prostacyclin analogue OP-2507 ; Working rat heart preparation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We examined the effects of a new stable prostacyclin analogue, OP-2507, on myocardial function and metabolism in the ischemic working rat heart preparation. The hearts were perfused with Krebs-Henseleit bicarbonate (KHB) buffer, and whole heart ischemia was induced by one-way aortic valve for 15 min follows by reperfusion for 30 min. In the treated hearts, OP-2507, 20 ng·ml−1, was administered to KHB buffer from the beginning to the end of experiment. During ischemia, coronary flow in the OP-2507 group increased significantly more than that in the control group. The mechanical performance of both groups was impaired after ischemia. However, the recovery of coronary flow, cardiac output, peak systolic pressure and LV dP/dTmax was significantly higher in the treated group than in the control group. The incidence of ventricular fibrillation during reperfusion was 100% and 25% in the control and the OP-2507 groups, respectively. Myocardial ATP content was significantly higher in the treated hearts than that in the control hearts. These results indicate that this stable prostacyclin analogue is beneficial in myocardial ischemia, even without its well known action of preventing platelet aggregation. (Oguchi T, Kashimoto S, Nakamura T, et al.: Effects of prostacyclin analogue, OP-2507, on function and metabolism in the ischemic working rat heart. J Anesth 6: 446–454, 1992)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s0054020060446
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  • 2
    Electronic Resource
    Electronic Resource
    Changes in myocardial nonesterified fatty acids during ischemia and reperfusion in isolated, perfused, working rat hearts (1990)
    Springer
    Heart and vessels 6 (1990), S. 21-30 
    Details
    ISSN: 1615-2573
    Keywords: Myocardial ischemia ; Nonesterified fatty acids ; Lactate ; High energy phosphate ; Isolated rat heart
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The time course of changes in the myocardial levels of nonesterified fatty acids (NEFA), adenosine triphosphate (ATP), creatine phosphate (CrP) and lactate, and those in the cardiac mechanical function during ischemia and reperfusion was investigated in the isolated, perfused, working rat heart. Ischemia was produced by lowering the afterload pressure from 60 to 0 mm Hg, and reperfusion resulted from raising the afterload pressure to 60 mm Hg. Ischemia stopped the heart beat, and increased the myocardial levels of unsaturated NEFA (such as arachidonic, palmitoleic, and linoleic acids) as a function of the ischemic period; it decreased the myocardial levels of ATP and CrP, and increased the myocardial level of lactate. The level of arachidonic acid increased when the myocardial level of ATP fell below 5 µmol/g dry weight. Reperfusion after ischemia started the heart beat, and restored the mechanical function which depended on the preceding ischemic period. Reperfusion also increased the levels of ATP and CrP and decreased the level of lactate, whereas it further increased the levels of the NEFA that had been elevated by ischemia. The recovery of mechanical function was inversely correlated with the myocardial level of arachidonic acid during ischemia and reperfusion. We concluded that changes in the myocardial levels of NEFA during ischemia and reperfusion are different from those of ATP, CrP, and lactate, and suggest that the myocardial level of arachidonic acid during ischemia and reperfusion can be a sensitive and suitable marker for the recovery of mechanical function during reperfusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02301877
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of endothelin-1 on epicardial coronary tone, coronary blood flow, ECG-ST change and regional wall motion in anesthetized dogs (1991)
    Springer
    Heart and vessels 6 (1991), S. 191-196 
    Details
    ISSN: 1615-2573
    Keywords: Endothelin-1 ; Myocardial ischemia ; Epicardial coronary artery diameter ; Coronary blood flow ; Regional wall motion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of intracoronaryadministrated endothelin-1 on coronary hemodynamics and regional myocardial function were studied in anesthetized open-chest dogs. Epicardial coronary diameter (CoD) and coronary blood flow (CBF) were measured by a sonomicrometer of 10 MHz piezoelectric crystals and an electromagnetic flow probe on the left circumflex coronary artery (LCX). Regional wall motion was sonomicrometrically measured at regions supplied by the LCX and left anterior descending artery (LAD) and electrocardiograms were recorded. Endothelin-1, administered as a bolus injections into the LCX via an intracoronary cannula, in a dose-dependent manner reduced COD and CBF. The extent of the reduction of COD and CBF at a dose of 300 pmol was 12.3±1.5% (P〈0.01) and 86±5% (p〈0.01), respectively, of the control. The extent of CBF reduction and deterioration of systolic wall motion were linearly related with the dosage of endothelin-1. ST-elevation (lead II) and fatal ECG abnormalities, including complete atrioventricular block or ventricular fibrillation, were observed with doses above 60 and 100 pmol, respectively. Coronary angiography revealed that filling defects of dye were propagated from the third or distal branches to those of more proximal arteries when the doses of endothelin-1 were cumulatively infused into the LCX. Accordingly, lethal myocardial ischemia induced by endothelin-1 is produced by critical obstruction of rather small coronary vessels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02125096
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of propafenone on function and metabolism in the ischemic working rat heart (1992)
    Springer
    Heart and vessels 7 (1992), S. 169-174 
    Details
    ISSN: 1615-2573
    Keywords: Myocardial ischemia ; Myocardial metabolism ; Propafenone ; Working rat heart preparation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We examined the effects of propafenone, a new anti-dysrhythmic agent, on myocardial function and metabolism in ischemic working rat heart preparations. In the treated hearts, propafenone, 0.3 µg/ml and 3 µg/ml, were added to Krebs-Henseleit bicarbonate buffer perfusate throughout the experiments. Whole heart ischemia was induced through a one-way aortic valve for 15 min followed by reperfusion for 30 min. After induction of ischemia, the cardiac output, peak aortic systolic pressure, left ventricular dP/dtmax, and myocardial ATP concentration were greater in the treated hearts than in the untreated ones. All hearts in the untreated group developed ventricular fibrillation (Vf) at the beginning of the reperfusion period. On the other hand, no treated hearts had Vf at any time during the experiment. However, propafenone, 3 µg/ml, evoked a negative inotropic effect before and after ischemia. These results indicate that propafenone may contribute to early recovery from ischemia in myocardial function and metabolism, although it has a negative inotropic action.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01744601
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  • 5
    Electronic Resource
    Electronic Resource
    Control of ciliary orientation in ciliated sheets from Paramecium-differential distribution of sensitivity to cyclic nucleotides (1991)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 20 (1991), S. 38-46 
    Details
    ISSN: 0886-1544
    Keywords: cilia ; calcium ; cAMP ; differential response ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ciliated sheets of cell cortex were prepared from Triton-glycerol-extracted Paramecium to observe directly the change of ciliary orientation. The observation of the ciliary responses revealed the modes of ciliary control by Ca2+ and cyclic nucleotides. The cilia changed their pointing direction clockwise from 11-12 to 5 o'clock (with the anterior of the cell defined as 12 o'clock) in the horizontal plane of cell surface when Ca2+ concentration was decreased from 10-6 M to 10-7 M. Cyclic AMP competed with Ca2+ ion in determining the orientation of the cilia. On the other hand, cGMP tended to change the ciliary orientation toward 3 o'clock. Ciliary sensitivity to cyclic nucleotides depended on their location on the cell surface. The cilia on the left-hand field of the cell were more sensitive to cyclic nucleotide than those on the right-hand field. The differential distribution of ciliary sensitivity within a single cell seems to be functional in the sophisticated turning mechanism in the behavioral response of Paramecium.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970200105
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  • 6
    Electronic Resource
    Electronic Resource
    Selective lectin-binding sites of primordial germ cells in chick and quail embryos (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 233 (1992), S. 625-632 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: To ascertain the histochemical characteristics of surface carbohydrates on avian primordial germ cells (PGC), we examined the distribution of binding sites for several biotinylated lectins in chick and quail embryos. Some binding sites were detected almost selectively with PGC but not with other embryonic sites. Of these, lectin from Sojanum tuberosum (STA) reacted with PGC in both avian species, whereas lectin from Wistaria floribunda (WFA) and Griffonia simplicifolia II (GS-II) reacted in the quail and the chick, respectively. The binding site for STA was found at the cell surface and cytoplasm of the PGC from their initial appearance in the germinal crescent through migration to sexually indifferent gonads, whereas the WFA reaction was seen at stages before and during migration. These reactivities showed most intensely on the surface of PGC at the peak of their migration. In contrast, GS-II binding site was restricted to the cytoplasm, and its distribution was similar to that of the periodic acid-Schiff (PAS)-positive glycogen granules in chick PGC. These results suggest that some selective binding sites on the PGC surface play a significant role in their migration and show that lectins STA, WFA, and GS-II can be used as probes for identification of the avian PGC. © 1992 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092330416
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  • 7
    Electronic Resource
    Electronic Resource
    Ectopic colonization of primordial germ cells in the chick embryo lacking the gonads (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 229 (1991), S. 109-115 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Chick primordial germ cells (PGCs) first appear in the extraembryonic region in the early embryo, then temporarily circulate via the blood vascular system and finally migrate into the gonadal anlagen. In the present study, we examined the trend of ectopic distribution of PGCs in the chick embryo when its future gonadal region had been removed a t an early stage. Embryos at stage 10, from which the caudal third region was excised, were incubated until they reached stages 14 to 20. In embryos at stage 14, about 80% of the total PGCs were found in the capillaries of the yolk sac, whereas others were observed in the head, mainly in the mesenchyme and small vessels close to the neural tube. From stage 18 onward, many PGCs accumulated in the embryo proper; about 90% of them colonized in the head region around the neural tube. These ectopic PGCs in the head were found in the capillaries, sometimes as thrombi or emerging from them into the adjacent mesenchyme. These results show that, when the chick embryo lacked gonads, the PGCs could be concentrated in the head region and migrated from the capillaries into the mesenchyme.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092290112
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  • 8
    Electronic Resource
    Electronic Resource
    Studies of variant palatal rugae in normal and corticosteroid-treated mouse embryos (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 230 (1991), S. 121-130 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Fourteen- and 15-day mouse embryos treated with triamcinolone on day 11 of gestation were examined for the presence of variant rugae. Nontreated mouse embryos served as controls. Variant rugae found were classified into five types. All five types of variations (bifurcation, division, supernumerary, shortness and cross) were observed in triamcinolone-treated embryos, and shortness was most frequently seen. Supernumerary, bifurcation and division were ranked next, following by cross. Variant, rugae, except the cross, were also observed in nontreated embryos in low frequencies, but more than one-half of them were the bifurcation of the second ruga. Divided rugae ranked next, and supernumerary and shortness were found occasionally. Except for the bifurcated and supernumerary rugae, the greater part of the variant rugae were found in the fifth and fourth ruga in the triamcinolone-treated groups and in the fifth ruga in the nontreated groups. As the incidence of variant rugae in the triamcinolone-treated embryos was significantly higher than that in the nontreated, it was regarded as one of the changes induced by the corticoid. Based on the characteristic features of the rugal region, it is speculated that the formation of variant rugae is associated with the disturbance of normal epithelial-mesenchymal interaction which may be controlled by the nerve fibers appearing at the time of rugal formation. The relationship between the increased appearance of variant rugae and the failure of palatal shelf elevation was examined, but no direct evidence was obtained.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092300112
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  • 9
    Electronic Resource
    Electronic Resource
    Ultrastructural characteristics of primordial germ cells in the quail embryo (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 236 (1993), S. 547-552 
    Details
    ISSN: 0003-276X
    Keywords: Primordial germ cells ; Ultrastructure ; Nucleolus ; Quail embryo ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An avian species, the quail has become a desirable animal model in experimental embryology and reproductive biology. To understand the ultrastructural characteristics of primordial germ cells (PGC) of this species, we studied PGC in the Japanese quail (Coturnix coturnix japonica) embryo at various developmental stages from their appearance in the germinal crescent through migration to settlement in the gonadal ridges by means of electron microscopy. The results were compared with those of another well-known avian species, the chick. Several ultrastructural characteristics of quail PGC not described previously in chick PGC were observed as follows: (1) No glycogen particles were detected in the cytoplasm at any stage examined. (2) Electron-dense and membrane-bounded granules were found in the PGC cytoplasm during the sexually indifferent gonadal stages. (3) Quail PGC were characterized by a prominent nucleolus associated with condensed chromatin (heterochromatin), and the developmental changes of the nucleus, were noted; the nucleolus initially appeared as a compact mass at the germinal crescent stage and became dispersed at later stages during the colonization of the gonadal ridges. These findings suggest several physiological and functional differences in the cell cycle between these two avian species. This is the first report describing detailed ultrastructural characteristics of PGC in the quail embryo. © 1993 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092360314
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  • 10
    Electronic Resource
    Electronic Resource
    Translocation of enamel proteins from inner enamel epithelia to odontoblasts during mouse tooth development (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 238 (1994), S. 383-396 
    Details
    ISSN: 0003-276X
    Keywords: Tooth development ; Mouse ; Protein translocation ; Amelogenin ; Epithelial-mesenchymal interactions ; Intercellular communication ; Immunocytochemistry ; Differential gene expression ; In vitro organ culture ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The developmental problem of how dental epithelia and/or dental papilla ectomesenchyme induce and/or up- or down-regulate tooth formation are as yet unresolved issues. We have desinged studies to map the synthesis and fate pathways of secreted amelogenin proteins from Kallenbach differentiation zones II-IV during in vivo and in vitro mouse mandibular first molar tooth development (M1). Tooth organs from cap, bell, and crown stages were processed for reverse transcriptase/polymerase chain reaction (RT-PCR) and high resolution Protein A immunocytochemistry using anti-amelogenin and anti-peptide antibodies. Cap stage M1 were cultured for periods ranging from 10-21 days in vitro using either serumless, or 15% fetal calf sera-supplemented, chemically-defined medium. Amelogenin transcripts are expressed in the mouse embryonic molar from E15 through early postnatal development. Amelogenin antigens were first detected in Kallenbach's differentiation zone II. Amelogenin proteins secreted from preameloblasts were identified along cell processes and cell surfaces of odontoblasts adjacent to forming mantle dentine extracellular matrix (ECM) prior to biomineralization. Amelogenin proteins were restricted to forming endocytotic vesicles, clathrin-coated vesicles, and lysozomes within odontoblasts. At later stages (e.g. 2 days postnatal development), enamel proteins were not identified in odontoblasts or predentine matrix following mineralization. Comparable observations for stages of development were noted for in vitro cultured tooth explants. Preameloblasts synthesize and secrete amelogenin proteins which bind to odontoblast cell surfaces possibly through the process of receptor-mediated endocytosis. We conclude that amelogenin proteins secreted from preameloblasts, prior to the initiation of biomineralization, were translocated to odontoblasts to serve as yet unknown biological functions. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092380313
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