Long-term fate of isolated congenital absent pulmonary valve.
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Cardiomegaly↗
Biomedical subjects
A Shibata
Publications and source records attributed to A Shibata.
An attempt at electrical catheter ablation of the arrhythmogenic area in idiopathic ventricular fibrillation.
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Adolescent↗
Balloon catheter with check valves for experimental relief of acute aortic regurgitation.
To evaluate the ability of a newly designed balloon catheter with check valves to temporarily relieve hemodynamic deterioration in acute aortic regurgitation, we produced an experimental model of acute aortic regurgitation in closed-chest dogs using endomyocardial biopsy forceps. Aortic regurgitation was produced until an increase in aortic pulse pressure of over 50% was achieved. Left ventricular end-diastolic pressure rapidly increased after the production of aortic regurgitation. Immediately after the catheter began functioning, pulse pressure decreased from 133 +/- 1 to 78 +/- 5 mm Hg (mean +/- SEM) and left ventricular end-diastolic pressure also decreased from 26 +/- 1 to 13 +/- 1 mm Hg. These effects lasted as long as the catheter functioned. Although a mild (21 +/- 8 mm Hg) pressure gradient between the left ventricular peak systolic pressure and the aortic peak systolic pressure was observed when this catheter was used, forward stroke volume was no less than in the group in which the catheter had not been used. These findings suggest that the balloon catheter with check valves may effectively reduce aortic regurgitation.
Animals↗
Location and dynamics of alpha-tocopherol in model phospholipid membranes with different charges.
Studies were made on the position and dynamics of the OH-group of alpha-tocopherol in phospholipid membranes. There was no difference in the spin-lattice (T1) relaxation times at the 5a-position of alpha-tocopherol labeled with 13C- or C19F3-determined from the nuclear magnetic resonance (NMR) spectra of liposomes positively charged with stearylamine (SA) and negatively charged with dicetylphosphate (DCP). The zeta-potentials of egg yolk phosphatidylcholine (EYPC) liposomes with and without SA or DCP were not affected by incorporation of 20 mol% alpha-tocopherol, though incorporation of 10 mol% ascorbyl-palmitate decreased the zeta-potentials of EYPC and EYPC-SA liposomes. The P==O stretching band (1235 cm-1) of the phosphate group and C==O stretching band (1734 cm-1) of the acyl ester linkage in dimyristoylphosphatidylcholine (DMPC) liposomes, measured by Fourier transform-infrared (FT-IR) spectroscopy, were not changed by incorporation of alpha-tocopherol. These results suggest that no specific interaction occurred between the OH-group of alpha-tocopherol and the polar interfacial region of the bilayer. The dynamic quenching effects of n-(N-oxy-4,4'-dimethyloxazolidine-2-yl)stearic acids (n-NSs) on the intrinsic fluorescence of alpha-tocopherol were in the order 5-NS > 7-NS = 12-NS > 16-NS. Acrylamide, a water-soluble fluorescence quencher with a very low capacity to penetrate through phospholipid bilayers, had very low quenching efficiency. These results indicate that the bulk of the chromanol moiety of alpha-tocopherol is located in a position close to that occupied by the nitroxide group of 5-NS in the membranes and is poorly exposed at the membrane surface.(ABSTRACT TRUNCATED AT 250 WORDS)
Electrochemistry↗
An immunosuppressant compound, FK-506, prevents the progression of autoimmune myocarditis in rats.
A new immunosuppressive compound, FK-506, is a macrolide produced by Streptomyces tsukubaensis. It is reported that FK-506 prolongs the viability of allogenic grafts of the heart and kidney in vivo and inhibits the development of autoimmune diseases. Furthermore, immunosuppressive therapy of myocarditis in humans has been given special attention by various observers; however, it is controversial. This study investigates the effects of FK-506 on experimental autoimmune myocarditis in rats. We performed two experiments. In Experiment 1, FK-506 was given intramuscularly on Days 11-20 after the first immunization. The rats were immunized twice (on Day 0 and Day 7). They were injected subcutaneously in the footpads with 1.0 mg of human cardiac myosin in equal volumes of complete Freund's adjuvant supplemented with Mycobacterium tuberculosis. They were divided into four groups: Control (six rats, saline), group 1 (six rats, FK-506: 0.1 mg/kg/day), group 2 (seven rats, FK-506: 0.32 mg/kg/day), and group 3 (six rats, FK-506: 1.0 mg/kg/day). To investigate the histologic extent of myocarditis, we formulated a histologic score (0-3). Histologic scores were: Control, 1.90 +/- 0.14; group 1, 0.97 +/- 0.46; group 2, 0.03 +/- 0.05; and group 3, 0 +/- 0. The indices of heart weight/body weight were: Control, 0.74 +/- 0.10%; group 1, 0.45 +/- 0.05%; group 2, 0.35 +/- 0.03%; and group 3, 0.35 +/- 0.03%. In Experiment 2, FK-506 was given on Days 1-10 after the first immunization, earlier than in Experiment 1. The rats were similarly divided into four groups. Each group was given the same dose of FK-506 as in Experiment 1. Histologic scores were: Control 1.49 +/- 0.24; group 1, 1.60 +/- 0.22; group 2, 0.29 +/- 0.41; and group 3, 0.03 +/- 0.03. The indices of heart weight/body weight were: Control, 0.69 +/- 0.15%; group 1, 0.76 +/- 0.09%; group 2, 0.42 +/- 0.08%; and group 3, 0.37 +/- 0.03%. Accordingly, in Experiments 1 and 2, the effects of FK-506 on autoimmune myocarditis were dose-dependent. On the other hand, in Experiments 1 and 2, not only in the control group but also in all treated groups, the titers of anti-myosin IgG were high. In conclusion, even if it is administered just before the onset of myocarditis, FK-506 is extremely effective at suppressing autoimmune myocarditis, despite a high titer of anti-myosin IgG.
Animals↗
A new myeloblastic leukemia cell line with double minute chromosomes. Induction of methotrexate resistance and dihydrofolate reductase gene amplification.
To test the relationship between DMs and drug resistance in newly established AML cell lines, KY821, and its clone KY821A3, the latter had lost DMs during cloning, were cultured in increasing concentrations of MTX. KY821 became resistant against 2 x 10(-4) M MTX, whereas KY821A3 did against 2 x 10(-5) M MTX in a same period. Enhanced enzyme activities of DHFR were correspondent to the increased DMs numbers and DHFR gene amplification in both resistant clones. The amplified DHFR gene was located on DMs by in situ hybridization. These data indicated that the presence of DMs in KY821 would facilitate the acquisition of drug resistance.
Chromosome Aberrations↗
In vitro purging of clonogenic leukemic cells from human bone marrow by heat: simulation experiments for autologous bone marrow transplantation.
In order to apply a simple purging method by heat to autologous bone marrow transplantation (ABMT), we have revaluated the ability to purge clonogenic leukemic cells from the simulated marrow mixture of normal marrow cells and leukemic cell lines (HL-60, Molt-3 and HEL) in vitro by heat, using two different clonogenic assays for normal granulocyte-macrophage progenitors (CFU-GM) and leukemic cell lines. It appeared that in vitro hyperthermia (42 degrees C for 120 min) is able to selectively remove clonogenic leukemic cells from simulated tumor cell-normal marrow mixtures even when leukemic cell concentrations are increased up to 3 x 10(6) cells/ml in vitro, and results in a 4-6 log destruction of clonogenic leukemic cells/ml according to a limiting dilution assay, while leaving half of normal CFU-GM surviving. The hyperthermic purging of clonogenic leukemic cells was not affected in the presence of normal marrow cells in vitro. This high level of clonogenic leukemic cell depletion by heat correlated with that of immunologic and pharmacologic studies. These results suggest that in vitro hyperthermia could be applied effectively and safely for the elimination of residual clonogenic leukemic cells in autologous marrow grafts before ABMT.
Bone Marrow Purging↗
Neoplastic basophil/mast cell precursors from chronic myelogenous leukemia display heterogeneous responses for a hematopoietic factor.
The response of neoplastic basophil/mast cell precursors to various hematopoietic factors was examined. Blastic or promyelocytic immature cells were obtained from six patients in basophilic crisis of chronic myelogenous leukemia. In all cases, after 14 days suspension culture more then 90% of the cells had basophilic features. 3H-thymidine uptake was markedly increased by the addition of GM-CSF in two cases, G-CSF in one, and IL-3 in two. In clonogenic cell assays, numerous colony formations were obtained when using the same growth factors as in the 3H-thymidine uptake assay. In addition, IL-3 induced colony formation in one case, despite a lack of thymidine uptake IL-4 had a synergistic effect on colony formation with IL-3 in one other case. None of the factors used showed any effect on differentiation. These findings indicate that the proliferation of neoplastic basophil/mast cell precursors may be regulated by various growth factors but response patterns are divergent.
Basophils↗
Gene introduction into granulocyte-macrophage progenitor cells by electroporation: the relationship between introduction efficiency and the proportion of cells in S-phase.
Our previous study demonstrated the positive relationship between the gene introduction rate into hematopoietic cell lines by electroporation and the percentage of cells in S-phase. In the present study, granulocyte-macrophage progenitor cells (CFU-C) rich marrow cell fraction were cultured in suspension with IL-3, GM-CSF and G-CSF for 4 days. The number of CFU-C were increased three times after the culture, and 3H-thymidine suicide tests of cultured cells demonstrated that the proportion of CFU-C in S-phase was increased by two to four times. The efficiency of gene transfer into CFU-C with the plasmid pMoZtk (containing the beta-galactosidase gene) by electroporation was nearly doubled by culturing marrow cells with these growth factors. These findings confirm that the introduction rate of the gene into CFU-C by electroporation is more efficient in cell populations with a higher percentage of CFU-C in S-phase.
Cell Count↗
Intake of vegetables, fruits, beta-carotene, vitamin C and vitamin supplements and cancer incidence among the elderly: a prospective study.
A cohort of 11,580 residents of a retirement community initially free from cancer were followed from 1981 to 1989. A total of 1,335 incident cancer cases were diagnosed during the period. Relative risks of cancer were calculated for baseline consumption of vegetables, fruits, beta-carotene, dietary vitamin C, and vitamin supplements. After adjustment for age and smoking, no evidence of a protective effect was found for any of the dietary variables in men. However, an inverse association was observed between vitamin C supplement use and bladder cancer risk. In women, reduced cancer risks of all sites combined and of the colon were noted for combined intake of all vegetables and fruits, fruit intake alone, and dietary vitamin C. Supplemental use of vitamins A and C showed a protective effect on colon cancer risk in women. There was some suggestion that beta-carotene intake and supplemental use of vitamin A, C, and E were associated with reduced risk of lung cancer in women, but none of these results were statistically significant. These inverse associations observed in women seem to warrant further investigation, although there was inconsistency in results between the sexes.
Aged↗
Fibrinolysis and fibrinogenolysis in patients with thrombotic disease.
In order to assess the fibrinolytic state in thrombotic disease, plasma levels of fibrin degradation products (FbDP) and fibrinogen degradation products (FgDP) were measured in 126 patients with a variety of thrombotic diseases. Mean plasma concentrations of both FbDP and FgDP were significantly elevated in patients with thrombotic disease as compared with healthy subjects. Plasma concentrations of FgDP were positively correlated with FbDP (r = 0.667, P less than 0.001). When analysed according to the disease categories, the magnitude of elevations of FbDP and FgDP was most prominent in venous thrombotic disease such as deep vein thrombosis and pulmonary embolism. These findings indicate that fibrinolysis is accelerated in patients with thrombotic disease and that fibrinolysis is frequently accompanied by some fibrinogenolysis in these patients.
Enzyme-Linked Immunosorbent Assay↗
Enhanced ex vivo proteolysis of plasma von Willebrand factor in disseminated intravascular coagulation.
Plasma levels of von Willebrand factor (vWf) are frequently elevated in patients with disseminated intravascular coagulation (DIC). To investigate the qualitative abnormalities of vWf and the possibility of its ex vivo modification in DIC, we analysed the multimeric composition of vWf in citrated plasma from 15 patients with DIC in the presence or absence of serine protease inhibitors (aprotinin and soybean trypsin inhibitor) and/or cysteine protease inhibitors (leupeptin, N-ethylmaleimide and EDTA). The proportion of large vWf multimers in plasma prepared in the presence of cysteine protease inhibitors was higher than those without such inhibitors. The addition of serine protease inhibitors during the preparation of plasma had no effect on the relative amounts of large multimers. The relative proportion of large multimers in plasma prepared without inhibitors and the difference between plasmas prepared with and without cysteine protease inhibitors correlated with plasma plasmin-alpha 2-plasmin inhibitor complex values, but not with other plasma or serum markers of DIC (platelet count, fibrinogen, FDP, D-dimer or thrombin-antithrombin III complex). We conclude that ex vivo proteolysis of plasma vWf occurs frequently in patients with DIC and cysteine protease inhibitors can protect this degradation.
Antifibrinolytic Agents↗
Comparison of prothrombin fragment 1 + 2 with thrombin-antithrombin III complex in plasma of patients with disseminated intravascular coagulation.
Plasma levels of prothrombin fragment 1 + 2 (F1 + 2) and thrombin-antithrombin III complex (TAT) are thought to be specific indicators of thrombin generation. To assess whether these two parameters behave similarly in vivo, we compared the plasma levels of F1 + 2 with TAT in 41 patients with disseminated intravascular coagulation (DIC). Both F1 + 2 and TAT were markedly elevated in patients with DIC compared to healthy subjects. Although a positive correlation was found between F1 + 2 and TAT (r = 0.585, P < 0.001) there was a large scatter among individuals. In addition, plasma concentrations of TAT were much lower than F1 + 2. The correlation between the TAT/F1 + 2 ratio and antithrombin III was weak (r = -0.268, P = 0.09). The TAT/F1 + 2 ratio was positively correlated with TAT (r = 0.481, P = 0.002), indicating that the difference in molar concentrations between F1 + 2 and TAT decreased as the TAT value increased. Serial determinations of these parameters showed that plasma TAT values changed roughly in parallel with F1 + 2 in the majority of patients. Although further studies are required to further clarify the observed differences between F1 + 2 and TAT, both parameters would be equally useful for the precise detection of haemostatic activation in patients with DIC.
Antithrombin III↗
Immunohistochemical characterization of infiltrating mononuclear cells in the rat heart with experimental autoimmune giant cell myocarditis.
The pathogenesis of giant cell myocarditis remains unclear. Subsets of inflammatory infiltrating cells may reflect the pathogenesis and etiology of the disease. Therefore, we examined subsets of infiltrating mononuclear cells in the heart of the rat with experimental giant cell myocarditis. Lewis rats were immunized with cardiac myosin in Freund's complete adjuvant (FCA). Severe myocarditis characterized by congestive heart failure and multinucleated giant cells were elicited. The lesions were composed of predominant mononuclear cells, polymorphonuclear neutrophils and fragments of degenerated myocardial fibres. The subsets of infiltrating mononuclear cells were investigated using MoAbs against rat CD4+ T cell (W3/25), CD8+ T cell (CX8), B cell (OX33) and macrophage (OX42). By serial examination, bound immunoglobulin could only be found on degenerated myocardial fibres. In this model, most infiltrating mononuclear cells were composed of macrophages and CD4+ T cells. The frequencies of macrophages and CD4+ T cells were 73.7% and 13.8%, respectively. CD8+ T cells were scarce and B cells were rare in the lesions. The frequencies of CD8+ T cells and B cells were 4.5% and 0.4%, respectively. The dominance of macrophages and CD4+ T cells was the constant finding among the sites of the lesions and throughout the course of the disease. These characteristic subsets of infiltrating cells were in contrast to those of murine viral myocarditis which were mainly composed of natural killer (NK) cells and CD8+ T cells. Clarifying the subsets of infiltrating cells in myocarditis may contribute to differential diagnosis of myocarditis between viral and autoimmune types. From this study, the pathogenesis of experimental autoimmune giant cell myocarditis seemed to be closely related to CD4+ T cells and macrophages.
Animals↗
DNA deletion in patients with von Recklinghausen neurofibromatosis.
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Alleles↗
Successful radiofrequency current catheter ablation of sustained ventricular tachycardia.
We performed radiofrequency current catheter ablation in two patients with nonischemic sustained ventricular tachycardia (VT). In one patient, two morphologically distinct VTs were induced by electrical stimulation. One showed right bundle branch block pattern and the other left bundle branch block pattern. The earliest site of activation during each VT was determined at the septum of the right ventricle. However, these two sites were close to the His-bundle electrogram recording area. In the other patient, a VT with a left bundle branch block pattern occurred spontaneously after the administration of isoproterenol. The earliest site of activation during VT was determined at the outflow tract of the right ventricle. During tachycardia, radiofrequency current ablation (40 W x 30 sec) was delivered to the earliest site of activation. A few seconds after fulguration, each VT was terminated and additional radiofrequency currents were given near these sites. After the ablation, VT could not be induced by the electrical stimulations, nor did it recur. No side effects were observed and the atrioventricular conduction remained intact. We feel that nonischemic VTs could possibly be treated by using radiofrequency current catheter ablation.
Aged↗
Frequency and output-dependent change in conduction over slow pathways in a patient with sustained ventricular tachycardia unrelated to coronary artery disease.
In a patient with sustained ventricular tachycardia, we obtained two different paced QRS morphologies from a single pacing site. In one QRS morphology the stimulus to the QRS complex was long, 150 msec, and in the other it was 100 msec. At the paced cycle length of 600 msec and the stimulus output of 4 V, one QRS morphology with the stimulus to the onset of QRS activation (St-QRS) interval of 150 msec was observed. At the paced cycle length of 400 msec, the other QRS morphology with a St-QRS interval of 100 msec was observed alternatively with the former. At the paced cycle length of 353 msec or 316 msec, the latter with a shorter St-QRS interval was exclusively observed. When the stimulus output was increased from 4 to 10 V, keeping with the paced cycle length at 400 msec, the St-QRS interval was shortened from 100 to 80 msec. For the two QRS morphologies with two St-QRS intervals, two slowly conducting pathways would be responsible. The site of the block in the faster pathway must be located at the proximity of the pacing site and the conduction at a shorter paced cycle length would be explained by "supernormal conduction."
Bundle-Branch Block↗
The Entner-Doudoroff pathway in Escherichia coli is induced for oxidative glucose metabolism via pyrroloquinoline quinone-dependent glucose dehydrogenase.
The Entner-Doudoroff pathway was shown to be induced for oxidative glucose metabolism when Escherichia coli was provided with the periplasmic glucose dehydrogenase cofactor pyrroloquinoline quinone (PQQ). Induction of the Entner-Doudoroff pathway by glucose plus PQQ was established both genetically and biochemically and was shown to occur in glucose transport mutants, as well as in wild-type E. coli. These data complete the body of evidence that proves the existence of a pathway for oxidative glucose metabolism in E. coli. PQQ-dependent oxidative glucose metabolism provides a metabolic branch point in the periplasm; the choices are either oxidation to gluconate followed by induction of the Entner-Doudoroff pathway or phosphotransferase-mediated transport. The oxidative glucose pathway might be important for survival of enteric bacteria in aerobic, low-phosphate, aquatic environments.
Biological Transport, Active↗