HAADF-STEM analysis of layered double perovskite La(2)CuSnO(6) grown epitaxially.

Structural observation of layered double perovskite oxide La(2)CuSnO(6) thin films grown epitaxially on SrTiO(3) is reported by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). Particularly the transition layer at the interface was observed, and the first B site layer at the interface was found to be almost formed by the Cu atomic layer as the random structure, followed by formation of the layered structure. In addition, HAADF-STEM images indicate that the thin film is not single crystalline, but some irregular structures were observed to grow around the interface near atomic steps of the substrate of SrTiO(3). Therefore, the steps largely affect the growth process of the thin film.

Local analysis of the edge dislocation core in BaTiO(3) thin film by STEM-EELS.

The a <100> edge dislocation core formed in an epitaxial BaTiO(3) (BTO) thin film grown on a substrate was investigated by scanning transmission electron microscopy combined with electron energy-loss spectroscopy. Elemental analysis using core-loss spectrum indicates that the atomic ratios of O/Ti and Ba/Ti are decreased at the dislocation core. The near-edge fine structure of the oxygen K-edge recorded from the dislocation core differs slightly from that of relaxed BTO region, which suggests that Ba-O bonding is decreased at the dislocation core. The structure of the dislocation core is discussed using a high-angle annular dark-field image and the electron energy-loss spectroscopy results.

Effects of electron channeling in HAADF-STEM intensity in La2CuSnO6.

Atomic resolution imaging using the high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) can be applied to analyze the atomic structures of materials directly. This technique provides incoherent Z-contrast with the atomic number of the constituent elements. In the present work, unique contrasts that make intuitively interpreting the HAADF-STEM image in double perovskite oxide La(2)CuSnO(6) difficult were observed. Multislice simulation confirmed that this occurred as an effect of the channeling process of electrons in combination with the effect of Debye-Waller factors. This was confirmed because in the La(2)CuSnO(6) crystal, two independent Sn atoms and four independent La atoms in the unit cell had different Debye-Waller factors, and the La columns consisted of pairs of columns with a small separation, whereas the Sn atoms were arranged straight. Furthermore, the image contrast was examined by mutislice simulation, and two atomic La columns were separated in a projected plane and appeared as one column contrast using multislice simulation. As a result, the HAADF intensity did not decrease constantly with the increase in column separation, with the exception of a very thin sample, which could be interpreted by the specific change in the electron-channeling process.

Sandwich technique via right ventricle incision to repair postinfarction ventricular septal defect.

We describe two cases where postinfarction ventricular septal defect (VSD) was treated with a new technique. Application of direct ultrasonography to the right ventricular (RV) wall enables the surgeon to visualize the region and perform appropriate incision into the right ventricle and trabecula resection. The VSD is sealed with gelatin-resorcin-formal (GRF) glue between two patches, one placed on the left ventricular side and the other on the right ventricular side. RV incision provides easy bleeding control and the "sandwich technique" using two patches and GRF sealing provides geometric preservation of the left ventricular shape and prevents residual shunt.

Branching ratio and L2 + L3 intensities of 3d-transition metals in phthalocyanines and the amine complexes

L(2,3) inner-shell excitation spectra were obtained by electron energy-loss spectroscopy (EELS) for the divalent first transition series metals in phthalocyanine complexes (MPc) such as titanium oxide phthalocyanine (TiOPc), fluoro-chromium phthalocyanine (CrFPc), manganese phthalocyanine (MnPc), iron phthalocyanine (FePc), cobalt phthalocyanine (CoPc), nickel phthalocyanine (NiPc) and copper phthalocyanine (CuPc). It was found that the value of normalized total intensity of I(L2 + L3) was nearly proportional to the formal electron vacancies of each 3d-state, and the values of the branching ratio, I(L3)/I((L2 + L3), represented a high-spin-state rather than low-spin-state for MnPc, FePc and NiPc. EELS was also applied to charge-transfer complexes of FePc with an amine such as pyridine or gamma-picoline. It was concluded that their I(L2 + L3) intensity of Fe showed the decrease in vacancies of 3d-states on the formation of the charge-transfer complex with these amines, which suggests some electron transfer from the amine to Fe in phthalocyanine. The EELS study provides beneficial information for investigating the electronic states of the specific metal sites in organic materials.

[Continuous monitoring of hepatic venous oxygen saturation (SHVO2) as a new diagnostic indicator of abdominal malperfusion in acute aortic dissection].

A 73-year-old woman was admitted with sudden-onset back and abdominal pain. Computed tomography scanning revealed type B acute aortic dissection with narrowing of the true lumen. We inserted an oximetric catheter into the right hepatic vein and started continuous measurement of ShvO2. The initial value was 20%. Consecutive aortograms showed an intimal tear in the thoracic descending aorta. Endovascular stent graft placement was performed to close the entry, and ShvO2 rose to more than 60% immediately after the stent graft expansion. ShvO2 is an excellent indicator of abdominal blood flow, not only for early diagnosis but also for the evaluation of treatment.

Structural studies on polymer whiskers by transmission electron microscopy: I. Morphological and high-resolution observations.

The structures of poly(p-hydroxybenzoic acid) (PHBA) whisker crystals and crystalline fine fibrils of copolymer prepared from p-hydroxybenzoic acid (HBA) and 2-hydroxy-6-naphthoic acid (HNA), namely poly(HBA/HNA) (monomer molar ratio: 97/3), were investigated by transmission electron microscopy (TEM). As for a PHBA whisker, microfibril-like bright regions were recognized in the 210 dark-field image. In the high-resolution TEM image of another PHBA whisker, however, lattice fringes were continuous through the whisker, showing that the whisker is highly crystalline and almost perfect. On the other hand, in the high-resolution images of poly(HBA/HNA) fine fibrils, granular crystallites (20-40 nm in lateral dimension) were observed. The lattice fringes in the crystallites were not successfully indexed with the orthorhombic unit cells of the homopolymer crystal, suggesting the coexistence of another different structure as a minor component.

[Clinical outcome of emergency coronary artery bypass grafting for acute myocardial infarction with cardiogenic shock].

From January 1993 through December 1998, Emergency Coronary Artery Bypass Grafting was Performed within 24 Hours after the Onset of Acute Myocardial Infarction (AMI) with Cardiogenic Shock in 22 Patients (17 men and 5 women; aged, 52-81 years). The incidence of AMI involving the left main coronary artery was 50%. The incidence of interventional therapy was 40.9% (PTCA 31.8%; PTCR 9.1%). The condition in 95.5% of the patients could be stabilized hemodynamically by preoperative intraaortic balloon pumping; 4 of the 5 patients suffered from cardiopulmonary arrest required percutaneous cardiopulmonary support. There were 4 (18.2%) deaths overall. Operative mortality was related to the intervals between AMI and operation (less than 6 hours, 25%; 6 to 24 hours, 10%). Three of the 4 patients who received cardiopulmonary support survived. We conclude that early revascularization and minimal reperfusion injury caused by mechanical devices are important determinants of survival in patients who have AMI with cardiogenic shock.

Antioxidant effects of albumin-bound sulfur in lipid peroxidation of rat liver microsomes.

The antioxidant potential of albumin-bound sulfur (SBA) was investigated in rat liver microsomes using lipid peroxidation systems in vitro. Sulfur bound to protein is a reduced metabolite which is produced from cystine by gamma-cystathionase. Lipid peroxidation was induced either chemically by ferrous ions and ascorbate or enzymatically by carbon tetrachloride or tert-butyl hydroperoxide as indicated by the increase in thiobarbituric acid reactive substances (TBA-RS) and oxygen consumption. Although the antioxidant effect of SBA was weak on the non-enzymatic lipid peroxidation system, the addition of SBA significantly inhibited TBS-RS formation and oxygen consumption compared with non-treated bovine serum alubumin (BSA) in a microsomal lipid peroxidation system induced enzymatically. The sulfur bound to albumin disappeared during incubation with liver microsomes. However, slight differences in the disappearance were observed depending on whether or not lipid peroxidation was induced in the enzymatic systems. In the CCl4-induced lipid peroxidation system, the cytochrome P-450 level was significantly decreased by the addition of SBA. Therefore, in cytochrome P-450 dependent lipid peroxidation system, the potential effects of sulfur bound to albumin are due to an inhibition of cytochrome P-450 rather than by the oxidation itself caused by radical trapping.

Triterpenoid saponins of Acanthopanax nipponicus leaves.

Five new triterpenoid saponins, nipponosides A-E (1, 3-6), were isolated from Acanthopanax nipponicus leaves, along with a known saponin, kalopanaxsaponin G (2). Nipponosides A-E were characterized as the 28-O-alpha-L-rhamnopyranosyl(1-->4)-beta-D-glucopyranosyl(1-->6)-beta -D-glucopyranosyl ester of 3-oxohederagenin, oleanolic acid 3-O-beta-D-glucopyranoside, gypsogenin 3-O-beta-D-glucopyranoside, 3beta,23,29-trihydroxyolean-12-en-28-oic acid, and 3beta,20alpha, 23-trihydroxy-30-nor-olean-12-en-28-oic acid, respectively. The structures of these new compounds were based on chemical and spectral methods.

3,4:9,10-Perylenetetracarboxylic dianhydride (PTCDA) by electron crystallography.

The crystal structures of the alpha and beta modifications of PTCDA were analyzed as projected structures along the a axes by electron crystallography using an imaging plate. The results for the alpha modification agree well with the sheet-and-stack structure obtained by X-ray diffraction by M. L. Kaplan et al. (private communication, full set of crystal structure data). Projected onto the (102) plane, which is parallel to the molecular sheets, the long molecular axis makes an angle of 42 degrees with the b axis and the hexagonal benzene rings appear slightly elongated, indicating a slight inclination of the molecular plane from the (102) lattice plane. For the beta modification, it was concluded that the molecules are aligned in a herringbone packing scheme on the (102) plane similar to that of the alpha modification, but with a slightly different angle of the long molecular axis with the b axis (38 degrees ).

A labile sulfur in trisulfide affects cytochrome P-450 dependent lipid peroxidation in rat liver microsomes.

The effects of trisulfide derivatives were studied on cytochrome P-450-dependent lipid peroxidation using rat liver microsomal systems. Cytochrome P-450-dependent lipid peroxidation was induced by carbon tetrachloride or tert-butylhydroperoxide and was evident by an increase in thiobarbituric acid-reactive substances (TBA-RS) and oxygen consumption. In these cytochrome P-450-dependent lipid peroxidation systems, pretreatment of microsome with trisulfide derivatives (cystine trisulfide and thiocyclam) significantly inhibited TBA-RS formation and oxygen consumption compared with disulfide or thiol analogs (cystine, nereistoxin, or cysteine). The labile sulfur contained in trisulfide disappeared during incubation with liver microsomes. In the CCl4-induced lipid peroxidation system, the cytochrome P-450 level and NAD(P)H-cytochrome P-450 reductase activity were significantly decreased by the addition of trisulfide derivatives. Therefore, in cytochrome P-450-dependent lipid peroxidation system, the potential effects of trisulfide appear to be mediated via enzyme inhibition. These results suggest that pretreatment of the trisulfide derivatives may affect the toxic function of exogenous xenobiotics or drugs, which are reduced by the liver enzyme cytochrome P-450 to radical species.

[Type A acute aortic dissection: late reoperations for dilatation of the distal false lumen and aortic regurgitation].

From January 1990 to December 1996, 71 patients aged 33 to 79 years (mean 60 +/- 11) underwent an emergency operation for type A acute aortic dissection. Fifty-three (74.6%) survived, and were followed 7 to 94 months (mean follow up 2.9 +/- 1.8 years) after the first operation. Five patients underwent reoperation for dilatation of the distal false lumen 7 to 52 months (mean period, 25 months) after primary repair. One patient underwent replacement of the arch and descending aorta, three patients underwent replacement of the descending aorta, and one patient underwent the stented graft implantation, resulting in closure of the entry site. Three patients underwent reoperation for severe aortic valve regurgitation 12 to 31 months (mean period, 24 months) after primary repair. Two patients underwent aortic valve replacement, and one patient underwent aortic root replacement. The actuarial freedom from reoperations was 81 +/- 6.9% at 3 years, and 73 +/- 9.9% at 5 years.

Structural analysis of A-protein of cucumber green mottle mosaic virus and tobacco mosaic virus by synchrotron small-angle X-ray scattering.

The size and shape of A-protein of tobacco mosaic virus coat protein (TMVP) and cucumber green mottle mosaic virus coat protein (CGMMVP) were evaluated by means of small-angle X-ray scattering (SAXS) using a synchrotron radiation source, complemented by electron microscopic observations. The results imply that TMV and CGMMV A-proteins are composed of three and two subunits, respectively, stacked in the shape of an isosceles triangular prism at lower ionic strength. Considering the difference of the A-protein structure at higher and lower ionic strength, the globular core structure was proposed as a subunit which might be modeled as a thin isosceles triangular prism composed of four globular cores joined by rather flexible segments. These cores correspond probably to four helical regions in a subunit, and rearrange their relative positions according to the external conditions. A slight rearrangement of core positions in a subunit may result in the formation of A-proteins of various shapes.

Pericardium-lined skeletal muscle ventricles: up to two years' in-circulation experience.

BACKGROUND: Skeletal muscle ventricles (SMVs) are autologous pumping chambers constructed from skeletal muscle. Skeletal muscle ventricular rupture and thromboembolism have complicated chronic models of this method of skeletal muscle cardiac assist. METHODS: The SMVs were constructed from the latissimus dorsi muscle in 10 dogs. The inner surface of each SMV was lined with autologous pericardium harvested at the time of SMV construction. After a 3-week period of vascular delay and 6 weeks of electrical conditioning to convert the muscle to a fatigue-resistant state, SMVs were connected to the descending thoracic aorta and stimulated to contract during cardiac diastole. RESULTS: Initial hemodynamics revealed that SMV contraction at 33 Hz increased diastolic pressure 24.7% (60.8 +/- 7.3 mm Hg versus 80.3 +/- 8.8 mm Hg). Skeletal muscle ventricle relaxation decreased presystolic pressure 14.4% (59.9 +/- 7.7 mm Hg versus 51.3 +/- 7.5 mm Hg) and decreased peak systolic pressure 4.1% (90.2 +/- 7.3 mm Hg versus 86.5 +/- 5.8 mm Hg). Hemodynamics were assessed at 1 to 2 weeks, then at 1, 2, 3, and 6 months, and at 6-month intervals thereafter. Hemodynamic performance remained stable for the duration of this study. After 2 years of pumping continuously in circulation, SMV contraction resulted in a 34.8% augmentation of diastolic pressure (63.6 +/- 6.6 mm Hg versus 85.3 +/- 6.4 mm Hg), a 17.2% decrease in presystolic pressure (54.7 +/- 3.73 mm Hg versus 45.3 +/- 4.1 mm Hg), and a 4.2% decrease in peak systolic pressure (95.3 +/- 10.4 mm Hg versus 91.3 +/- 12.3 mm Hg). Three dogs survived to 2 years with the SMVs in circulation. No animal showed evidence of thromboembolism during serial echocardiography or at autopsy and no SMVs ruptured. CONCLUSIONS: These data demonstrate that SMVs can provide effective hemodynamic assist over an extended period without specific complications related to the SMVs.

Skeletal muscle ventricles: frontiers in 1995.

Skeletal muscle ventricles (SMVs) constructed from electrically conditioned latissimus dorsi muscle (LDM) may become an alternative for assisting the failing heart. Left and right heart circulatory assist using SMVs has been performed successfully in both acute and chronic animal models. The configurations used to connect SMVs to the circulation have included a left atrium to aorta bypass, a left ventricle apex to aorta bypass, aortic counterpulsators, a cavopulmonary bypass, and a right ventricle to pulmonary artery bypass. One SMV used as an aortic counterpulsator functioned effectively in the circulation for more than 27 months. Recent application of the pericardium to the SMV as an inner layer and design changes in the connection of the SMV to the circulation have reduced the risk of thrombus formation and SMV rupture. Although several problems have yet to be solved, the goal of the SMV as a permanent circulatory assist device without the limitation of an external power source seems within reach.

Skeletal muscle ventricles in circulation: decreased incidence of rupture.

BACKGROUND: Skeletal muscle ventricles (SMVs) are muscular pumping chambers constructed for cardiac assist. Skeletal muscle ventricles can be connected to the circulation in a variety of configurations for both left and right heart assist; when connected to the aorta and stimulated to contract during diastole, they function in a similar fashion as an intraaortic balloon pump. METHODS: Skeletal muscle ventricles were constructed in 18 dogs using the left latissimus dorsi muscle. In 10 of these dogs (group 1), the inner surface of the SMV was lined with autogenous pericardium obtained at the time of construction of the SMV. For the remaining 8, the SMVs were lined by fibrous tissue that forms in reaction to the synthetic mandrel around which the latissimus muscle is wrapped. After the muscles were electrically conditioned to a fatigue-resistant state, the mandrels were removed from the SMVs and the SMVs were connected to the descending thoracic aorta with a specially constructed base cap and two polytetrafluoroethylene conduits. RESULTS: Initial hemodynamic recordings revealed that the mean diastolic blood pressure increased by 24.7% in group 1 and by 29.8% in group 2. Diastolic augmentation was well maintained over time; augmentation in surviving group 1 animals was 30.0% after 18 months of pumping continuously in circulation. Long-term survival was greater in the dogs whose SMVs were constructed using an inner pericardial lining. At 90 days in circulation, 60% of the dogs in group 1 were alive with functioning SMVs, whereas only 13% of the dogs in group 2 were alive. The incidence of SMV rupture in the fibrouslined SMVs was 63%, whereas the incidence in the pericardial-lined SMVs was 0%. No evidence of thromboembolism occurred in either group. CONCLUSIONS: Lining the inner surface of an SMV with pericardium appears to provide structural integrity, which helps to prevent the complication of SMV rupture in this model of cardiac assist.

Chronic changes of end-systolic pressure-volume relationship after regional myocardial infarction.

The chronic changes of the end-systolic pressure-volume relationship (ESPVR) after regional myocardial infarction were evaluated in a sheep model. Pressure-volume area (PVA) obtained from the pressure-volume diagram and left ventricular oxygen consumption (LVO2) were studied. The regional myocardial infarction was created by ligating distal branches of the left coronary artery. ESPVR was obtained using a conductance catheter during transient inferior vena cava occlusion. Measurements were performed at baseline (n = 13), 1 hour (n = 8), 3 months (n = 9), and 6 months (n = 4) after infarction. Ees, the slope of the ESPVR did not change at 1 hour after infarction and remained the same at 3-month and 6-month measurements (baseline 2.26 +/- 1.24 mmHg/mL, 1 hour 2.71 +/- 1.06, 3 months 3.46 +/- 1.51, 6 months 2.45 +/- 0.64, NS). Because of the ventricular dilatation, which was demonstrated as an increase in changes of end-systolic volume (Ves) correlating with the time course after infarction (y = -3.21 + 0.12x, r = 0.454, p < 0.05), V0, the volume intercept of the ESPVR increased at 1 hour after the infarction, and showed a tendency to increase at 3 months and 6 months after the infarction (baseline -18.0 +/- 22.5 mL; 1 hour -0.9 +/- 11.6; 3 months 5.4 +/- 10.9, 6 months 9.2 +/- 23.1, baseline vs 3 months p < 0.05, baseline vs 6 months p < 0.05). PVA and LVO2 were unchanged over time after infarction (PVA: baseline 2097 +/- 1526 mmHg/mL per 100 g-1; 1 hour 1771 +/- 699; 3 months 2483 +/- 1086; 6 months 1,608 +/- 1,010, NS), (LVO2: baseline 40.6 +/- 13.1 x 10(-3) mL/100 g-1 per beat-1; 1 hour 42.9 +/- 9.7; 3 months 35.0 +/- 8.6; 6 months 31.2 +/- 18.1, NS). Chronic regional infarction in the sheep model did not affect Ees over 6 months, but significantly increased V0 after the increase in the acute phase. PVA and LVO2 were not affected by this regional infarction either acutely or over 6 months.

Reconstitution of an iron-sulfur cluster with bound sulfur: a possible source of acid-labile sulfur in biological systems.

The reconstitution of the iron-sulfur cluster of spinach ferredoxin was examined in vitro using low and high molecular bound sulfur components as sulfur donors. Bound sulfur was rapidly converted to acid-labile sulfur to form an iron-sulfur center in the presence of dihydrolipoate and iron. Reconstitution yields of above 95% were obtained with cystine trisulfide (CT, 0.25 mM) and sulfur-bound albumin (SBA, 1.0 mM) at 37 degrees C, pH 7.3, following 60 min incubation. Spectroscopic features and biological activity of the reconstituted ferredoxin were identical to those of the native holo-protein. The acid-labile sulfur content found in the isolated reconstituted ferredoxin was 2 atoms/mol protein, similar to the theoretical value. A possible role for bound sulfur in mammalian cells is indicated and discussed.

Skeletal muscle ventricles seeded with autogenous endothelium.

Skeletal muscle ventricles (SMVs) are muscular pumping chambers constructed from skeletal muscle. Previously, SMVs were connected to the systemic circulation with vascular conduits and used to assist the heart. In this study, SMVs were constructed from the latissimus dorsi muscle in eight dogs. The SMVs were seeded with autologous endothelial cells, but not connected to the circulation. Endothelial cells were harvested enzymatically from autogenous external jugular vein and grown in tissue culture. After 9 weeks, 6 electrically conditioned SMVs were seeded with endothelial cells by injecting 4-5 ml of culture medium containing 5-8 x 10(6) autogenous endothelial cells into each SMV lumen adjacent to the mandrel. Conditioning was stopped at the time of endothelial seeding. One week after seeding, electrical conditioning was resumed. Two weeks after seeding, the animals were killed and the SMVs excised. Histologic examination confirmed the presence of a confluent monolayer of cells covering 80-100% of the luminal surface in each seeded SMV. The endothelial nature of the cells lining the SMV lumen was established by fluorescent microscopy. Endothelial cells were pre labeled with the cellular marker PKH before seeding; the SMVs were also incubated with the endothelial marker dil-acetylated LDL. Endothelial cells also were identified by staining with fluorescently labeled antibodies to von Willebrand factor. Based upon these data, electrically conditioned SMVs can be seeded successfully with a near-complete, autologous endothelial monolayer. Additionally, this endothelial monolayer can be maintained on the luminal surface of a contracting SMV. In-circulation studies will determine whether endothelial cell seeding of SMVs can decrease or eliminate the incidence of thromboembolism.