Biomedical subjects

S Isoda

Publications and source records attributed to S Isoda.

At least 19 recordsLinked to original sources

PubMed2000

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.

Journal Article↗

PubMed2000

[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.

Abdomen↗

PubMed1999

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 ).

Journal Article↗

PubMed1999

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.

Carbohydrate Sequence↗

PubMed1999

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.

Albumins↗

PubMed1999

[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.

Aged↗

PubMed1998

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.

Animals↗

PubMed1998

[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.

Adult↗

PubMed1997

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.

Capsid↗

PubMed1996

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.

Animals↗

PubMed1996

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.

Animals↗

PubMed1996

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.

Animals↗

PubMed1995

Influence of a delay on latissimus dorsi muscle flap blood flow.

The regional and total blood flow of canine latissimus dorsi muscle flaps (LDMFs) were examined to study the effect of a delay procedure, ligation of the perforators, before complete flap elevation. The regional blood flow of the middle and distal regions of the nondelayed LDMFs was poor and significantly lower than the proximal region at rest. The regional blood flow during the exercise test was improved and significantly higher in the middle (62% increase) and distal regions (187% increase) of the delayed LDMFs as compared with the nondelayed LDMFs. The mean total blood flow of the delayed LDMFs was 14 mL.min-1.100(-1) g at rest, increased to 30 mL.min-1.100(-1) g during exercise tests with intermittent burst electrical stimulation, and was maximal at 40 mL.min-1.100(-1) g immediately after the exercise. The phasic arterial blood flow of the delayed LDMFs was inhibited during contraction at 9 mL.min-1.100(-1) g, whereas it was 44 mL.min-1.100(-1) g during relaxation. In contrast, the phasic venous blood flow was accentuated during contraction to 32 mL.min-1.100(-1) g compared with 16 mL.min-1.100(-1) g during relaxation.

Animals↗

PubMed1995

Endothelial cell-lined skeletal muscle ventricles in circulation.

Skeletal muscle ventricles were constructed from the latissimus dorsi in six dogs by wrapping the muscle around a polypropylene mandrel. Jugular vein endothelial cells were harvested enzymatically and grown in tissue culture. After 3 weeks of vascular delay and 4 weeks of electrical conditioning, five skeletal muscle ventricles were seeded with 5 to 8 x 10(6) autologous endothelial cells by percutaneous injection of a cellular suspension into the lumen of the skeletal muscle ventricle; one skeletal muscle ventricle was injected with culture medium alone as an unseeded control. The autologous endothelial cells were all prelabeled with a lipid-bound cellular marker, PKH-26. After an additional 4 weeks of electrical conditioning, the mandrels were removed and the skeletal muscle ventricles were connected to the descending thoracic aorta and activated to contract during cardiac diastole at a 1:2 ratio with the heart. After 3 hours of continuous pumping, mean diastolic pressure was increased by 35% (58 +/- 7 versus 78 +/- 6 mm Hg, p < 0.05). At this time, the skeletal muscle ventricles were excised for histologic examination. Sections stained with hematoxylin and eosin revealed a continuous cellular layer lining the skeletal muscle ventricle; no cells were present on the lumen of the control skeletal muscle ventricle. All seeded skeletal muscle ventricles exhibited fluorescence as a result of the PKH-26 cellular marker. Immunofluorescent staining with antibodies to von Willebrand factor and ultrastructural analysis with an electron microscope confirmed the endothelial character of these cells lining the lumen of the skeletal muscle ventricles. The ability to create endothelial cell-lined muscular pumping chambers holds important implications for the resolution of thrombotic events in cardiac assist devices as well as toward the clinical application of skeletal muscle ventricles.

Animals↗

PubMed1995

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.

Animals↗

PubMed1995

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.

Circular Dichroism↗

PubMed1994

Banding a hemodialysis arteriovenous fistula to decrease blood flow and resolve high output cardiac failure: report of a case.

We report herein the successful surgical treatment of a patient with high-output cardiac failure which developed from a high-flow hemodialysis arteriovenous fistula of the Brescia-Cimino type. Banding correction of the venous limb of the fistula with a woven Dacron prosthesis resulted in marked improvement of the cardiac failure. An ultrasonic study showed the fistula flow of 3.2 l/min to be as high as 40% of the resting cardiac output, or 8.0 l/min, before banding, while an intraoperative electromagnetic study was useful for controlling the degree of banding and showing the decrease of fistula flow from 3.7 l/min to 1.4 l/min.

Aortic Aneurysm, Abdominal↗

PubMed1994

Chronic morphologic changes of skeletal muscle ventricles in circulation.

Skeletal muscle ventricles (SMVs) were constructed either extrathoracically or intrathoracically in 44 dogs using the left latissimus dorsi muscle. These SMVs functioned as aortic counterpulsators for from several hours to 216 days. In this study, the relationship between the morphologic changes in the SMVs and their time course in the circulation was evaluated retrospectively. The average volume of the SMV chamber after it had been excised and fixed in formalin was 21.3 +/- 11.0 mL (mean +/- the standard deviation) for extrathoracic SMVs and 20.0 +/- 7.5 mL for intrathoracic SMVs. The volume of the SMV chamber did not correlate with the time course in the circulation. The SMV wall was mainly composed of three components: muscular, fibrous, and fatty aspects. The overall thickness of the wall appeared to be preserved over time in the circulation. However, the thickness of the muscular component tended to decrease over time. SMV rupture occurred in 15 dogs between postoperative days 4 and 39. All ruptures occurred at the suture line between the SMV and the vascular conduits. There was some degree of thrombus in 24 SMVs. Before SMVs can be applied clinically for the purpose of cardiac assist, problems with rupture and thrombus formation must be solved. A better understanding of the morphologic changes that take place in the SMV over time also is needed.

Animals↗