Effect of exercise on the relationship between myocardial blood flow and systolic wall thickening in dogs with acute coronary stenosis

Relationships between regional myocardial perfusion and transmural function, both during treadmill exercise and at rest, were examined in conscious dogs with varying degrees of coronary stenosis produced by a hydraulic occluder. In 13 dogs we measured myocardial blood flow with microspheres (10-12 microns in diameter) and regional systolic wall thickening (%). During exercise with coronary stenosis, myocardial blood flow was characterized by nonuniform distribution, and associated with regional dysfunction. The relationships between normalized myocardial blood flow and normalized %wall thickening during exercise with coronary stenosis were linear, with significantly different slopes (mean myocardial blood flow: y = 1.23x - 0.16, r = 0.93; subendocardial myocardial blood flow: y = 1.50x - 0.02, r = 0.86; subepicardial myocardial blood flow: y = 0.83x - 0.18, r = 0.87). To fill the gap between available subendocardial and subepicardial data during exercise with coronary stenosis and control points, however, would require nonlinear components. In 10 of the dogs, coronary stenosis at rest was also produced to compare regional myocardial blood flow - %wall thickening relations at rest with those during steady state exercise. The absolute mean myocardial blood flow - %wall thickening relation during exercise with coronary stenosis (y = 11.6x - 1.9, r = 0.90) was significantly shifted rightward from the resting relation (y = 25.3x -2.1, r = 0.80). However, when changes in %wall thickening were plotted vs. myocardial blood flow per beat, the relationships at rest and exercise were nearly superimposable. Likewise, relations between normalized myocardial blood flow and changes in %wall thickening at rest and exercise were not significantly different. We conclude: %wall thickening during exercise is directly related to changes in mean myocardial blood flow but is related in nonlinear fashion to changes in subepicardial and subendocardial myocardial blood flow; %wall thickening may provide a reliable index of the relative transmural flow distribution during exercise as well as at rest; during brief bouts (5-8 minutes) of exercise with coronary stenosis, the relationship between stabilized regional contractile dysfunction and level of myocardial blood flow per beat is the same as that during coronary stenosis at rest.     

Assessment of transesophageal Doppler echography in dissecting aortic aneurysm

To assess the clinical value of transesophageal Doppler echography in the diagnosis of dissecting aortic aneurysm, both transesophageal and conventional echograms were performed in 22 cases of dissecting aortic aneurysm. Of the 22 patients, 17 underwent angiography; 8, X-ray computed tomography; 4, both; and 12, surgery. The performance of each method was assessed in the following four segments: A, ascending aorta; B, aortic arch; C, thoracic descending aorta; and D, upper abdominal aorta. The results by angiography were presumed to be correct. In the group of 17 patients who underwent angiography, the rate of correct detection of an intimal flap using the transesophageal approach was 100% in all four segments, significantly better than detection by the conventional approach (segment A, 65%; segment B, 47%; segment C, 35%; segment D, 53%) (p less than 0.01), and the rate of correct detection of the entry sites using the transesophageal approach was 100%, significantly better than that by conventional approach (42%) (p less than 0.05). X-ray computed tomography was not capable of detecting the site of entry in all cases. The presence of thrombus, aortic regurgitation and pericardial hemorrhage were all revealed clearly by the transesophageal approach, and the results were partly proved by other methods. In conclusion, transesophageal Doppler echography provides a rapid and accurate method of diagnosing and evaluating dissecting aortic aneurysm and permits prompt initiation of appropriate treatment.     

Recognition of regional hypertrophy in hypertrophic cardiomyopathy using thallium-201 emission-computed tomography: Comparison with two-dimensional echocardiography

The configuration of the hypertrophied myocardium was evaluated by thallium-201 emission-computed tomography and 2-dimensional (2-D) sector scan in 10 patients with obstructive hypertrophic cardiomyopathy (HC), 10 with nonobstructive HC with giant negative T waves and 10 with concentric left ventricular (LV) hypertrophy. Thallium-201 myocardial imaging was reconstructed into multiple 12-mm-thick slices in 3 planes. The thickness ratio of the ventricular septum and the LV posterior wall in the short-axis plane and the ratio of the ventricular septum and the apical wall in the long-axis plane were analyzed. In the patients with obstructive HC the ventricular septal wall thickness index was increased, and the ratio of septal to posterior wall thickness index (1.45 ± 0.23) was greater than that in the patients with nonobstructive HC with giant negative T waves or in those with concentric LV hypertrophy (1.03 ± 0.20 and 0.98 ± 0.11, respectively; p <0.01 for each). In the patients with nonobstructive HC with giant negative T waves, increased apical wall thickness with apical cavity obliteration was characteristic, and the ratio of ventricular septal to apical wall thickness index (0.66 ± 0.14) was less than that in the patients with obstructive HC or in those with concentric LV hypertrophy (1.46 ± 0.38 and 1.04 ± 0.09, respectively; p <0.001 for each). In contrast, technically satisfactory 2-D sector scanning (83%) demonstrated various configurations of the hypertrophied ventricularseptum, but could not detect apical hypertrophy in 4 of the 10 patients with nonobstructive HC with giant negative T waves whose LV cineangiograms demonstrated apical hypertrophy. Thus, thallium-201 emission-computed tomography is useful in evaluating the characteristics of LV hypertrophy and assists 2-D sector scan, especially in patients with apical hypertrophy in HC.     

Detection of localized retinal malfunction in retinal degeneration model using a multielectrode array system

Light stimulation inhibits the retinal dark current through phototransduction signals in the photoreceptors. Electroretinography (ERG) detects the blockage of the dark current as the a‐wave of the ERG. However, standard ERGs represent the summed neural activity of the retina, and information on localized functions cannot be obtained. In this study, we used a multielectrode array (MEA) system and directly recorded the focal activities of the photoreceptors of the retina. Retinas were isolated from dark‐adapted rodents and were draped over the electrode array with vitreal surface of the retina on the electrode array. After light stimulation, negative waves were recorded from each electrode. Adding aminobutyric acid, a selective agonist of mGluR6 expressed on ON‐bipolar cells, to the media did not block the generation of the responses. The amplitude of the response increased with increasing retinal development. When the retina was locally injured, light‐elicited responses were diminished only in the injured areas of the retina. Retinas isolated from rats given N‐methyl‐N‐nitrosourea (MNU) were also tested. In central retinas of MNU‐treated rats, the responses were progressively decreased following injection of MNU. In contrast, in the peripheral retinas, amplitude of the responses was relatively retained, consistent with the retinal thickness observed by immunohistochemistry. In conclusion, light‐evoked responses were recorded with the MEA system. The MEA system was useful for detecting subtle and focal activation of photoreceptors. This spatial information should be valuable in investigating local functional recovery in therapeutically treated areas, such as in gene transfer or cell transplantation. © 2009 Wiley‐Liss, Inc.     

Neural conversion of ES cells by an inductive activity on human amniotic membrane matrix

Here we report a human-derived material with potent inductive activity that selectively converts ES cells into neural tissues. Both mouse and human ES cells efficiently differentiate into neural precursors when cultured on the matrix components of the human amniotic membrane in serum-free medium [amniotic membrane matrix-based ES cell differentiation (AMED)]. AMED-induced neural tissues have regional characteristics (brainstem) similar to those induced by coculture with mouse PA6 stromal cells [a common method called stromal cell-derived inducing activity (SDIA) culture]. Like the SDIA culture, the AMED system is applicable to the in vitro generation of various CNS tissues, including dopaminergic neurons, motor neurons, and retinal pigment epithelium. In contrast to the SDIA method, which uses animal cells, the AMED culture uses a noncellular inductive material derived from an easily available human tissue; therefore, AMED should provide a more suitable and versatile system for generating a variety of neural tissues for clinical applications.     

Risk factors of thrombotic recurrence and major bleeding in patients with intermediate-risk for recurrence of venous thromboembolism

Journal of Thrombosis and Thrombolysis - Prolonged anticoagulation therapy is recommended for patients with intermediate-risk for recurrence of venous thromboembolism (VTE). The current study aimed...     

The contractile activities of neurokinin A, B and related peptides on smooth muscles

The contractile activities of neurokinin A (NKA), neurokinin B (NKB) and related peptides on the guinea-pig ileum, rat vas deferens and rat duodenum were compared to the activity of substance P (SP). The potencies of NKA and NKB on the guinea-pig ileum (SP-P tissue) were nearly the same as that of SP. NKA was approximately 250-400 times more potent than SP on the rat vas deferens (EC50 = 59.5 nM; SP, EC50 = 1500 nM) and rat duodenum (EC50 = 1.8 nM; SP, EC50 = 674 nM) (SP-E tissues). NKB also showed high contracting activity on the rat duodenum (EC50 = 3.1 nM) but was 10 fold less active than NKA on the rat vas deferens. These results suggest that neurokinin peptides are possible endogenous agonists for the SP-E tissues. The contractile potency of NKA and NKB remained nearly complete after removal of N-terminal tripeptide portions, i.e., His-Lys-Thr and Asp-Met-His from the native peptides, respectively. However, the removal of the Asp residue from both NKA7 and NKB7 decreased activity until it was similar to that of SP.     

Preparation of polyaniline by oxidation of aniline using H2O2 in the presence of an iron(II) catalyst

Oxidative polymerization of aniline using the H₂O₂-FeSO₄ system gave polyaniline under mild conditions. The prepared powdery emeraldine base, a form of polyaniline, is blue black and shows high solubility in organic solvents (e.g., ca. 200 mg/mL in N-methylpyrrolidone). The number-average molecular weight (M _n) of the polymer obtained was 1,3–1,7 · 10⁴ (via gel permeation chromatography vs. polystyrene) and M _w/M _n = 1,6–2,2. Poly(2-ethylaniline) and poly-(2-propylaniline) with high molecular weights were also synthesized by this procedure in high yield.     

Detection of anti-neutrophil cytoplasmic antibodies in MRL/Mp-lpr/lpr mice and analysis of their target antigens

Anti-neutrophil cytoplasmic antibodies (ANCA) have been widely studied and recognized to be clinically very important for some human diseases including systemic rheumatic diseases. We analyzed ANCA response and their target antigens in MRL/Mp-lpr/lpr (MRL-lpr) mice, an animal model of systemic rheumatic disease. P-ANCA was detected in 57% of the mice. Antibodies to the known P-ANCA target antigens at the same age were examined. Among these, antibodies to high mobility group (HMG) proteins HMG1 and HMG2 were detected in 57% of the mice, 75% of which were also positive for P-ANCA. These anti-HMG1/HMG2 activities were absorbed by preincubation with a mixture of HMG1 and HMG2. In contrast, antibodies to myeloperoxidase and cathepsin G were detected in 14% and 7%, respectively, but these activities were not inhibited by preincubation with corresponding antigens. In addition, the titers of P-ANCA and anti-HMG1/HMG2 antibodies in MRL-lpr mice were significantly correlated with each other. Thus, HMG1 and HMG2 were considered to be significant target antigens of P-ANCA in MRL-lpr mice.     

Ring‐Opening Copolymerization of 2‐Aryl‐1‐methylenecyclopropanes with Carbon Monoxide Initiated by Pd–bpy Complexes

[PdCl(Me)(bpy)] and a mixture of the complex with cocatalysts; NaBARF (BARF = [B{C₆H₃(CF₃)₂‐3,5}₄]^?), NaBF₄, AgBARF, AgBF₄, and AgOTf, catalyze the copolymerization of 2‐phenyl‐1‐methylenecyclopropane with carbon monoxide to produce a new polyketone accompanied by ring opening of the monomer. ¹H and ¹³C{¹H} NMR spectra indicate that the polymers have two isomeric repeating units in which the phenyl substituents occupy different positions. The molecular weights of the polyketones formed by the reactions with a [Pd]/[cocatalyst]/[2‐phenyl‐1‐methyleneyclopropane] ratio of 1:3:70 are in the range of M _n = 13 100–86 000. The polymer obtained by the reaction promoted by [PdCl(Me)(bpy)]/MBARF, where M = Ag or Na, shows a narrow molecular weight distribution, M _w/M _n = 1.44 and 1.59, respectively. The catalysis is effective also for the ring‐opening copolymerization of 2‐aryl‐1‐methylenecyclopropanes bearing Me and F substituents on the phenyl ring. Isotope‐labeled experiments revealed the mechanism of the polymerization, which involves a 1,2‐insertion of the monomer into the Pd–acyl bond to produce a cyclopropylmethyl palladium intermediate, and subsequent β‐alkyl elimination to give the Pd–alkyl complex.