Evaluation of left atrial function by the functional volume change curve derived from Doppler flow spectra

The objective of this study was to clarify the left atrial (LA) reservoir and booster pump function in patients with left ventricular (LV) diastolic dysfunction. To determine LA reservoir and booster pump function, a new algorithm to determine LA functional volume change curve (FVC) was developed from Doppler flow spectra of pulmonary venous flow and LV inflow by transthoracic echocardiography in 110 patients. Patients were classified into normal (N), and abnormal (AB) and pseudonormal (PN) groups on the basis of their Doppler flow patterns. From the indices of FVC, atrial reservoir volume (ARV), passive emptying volume (PEV) and active emptying volume (AEV) were obtained. ARV/stroke volume (SV) was increased in the AB group, but decreased in the PN group compared with N (N, 0.61+/-0.09; AB, 0.73+/-0.10; PN, 0.52+/-0.13, p<0.05). PEV/SV was significantly decreased in AB, but increased in PN compared with N (N, 0.27+/-0.07; AB, 0.19+/-0.07; PN, 0.31+/-0.18, p<0.05). AEV/SV was significantly increased in AB, but decreased in PN compared with N (N, 0.41+/-0.08; AB, 0.56+/-0.10; PN, 0.26+/-0.19, p<0.05). Thus, in patients with an abnormal relaxation pattern, the LA reservoir and booster pump function are augmented, but in patients with a pseudonormal pattern, both LA reservoir and booster pump function are deteriorated, suggesting a vulnerability to pulmonary congestion.

Dendritic spine geometry is critical for AMPA receptor expression in hippocampal CA1 pyramidal neurons

Dendritic spines serve as preferential sites of excitatory synaptic connections and are pleomorphic. To address the structure-function relationship of the dendritic spines, we used two-photon uncaging of glutamate to allow mapping of functional glutamate receptors at the level of the single synapse. Our analyses of the spines of CA1 pyramidal neurons reveal that AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid)-type glutamate receptors are abundant (up to 150/spine) in mushroom spines but sparsely distributed in thin spines and filopodia. The latter may be serving as the structural substrates of the silent synapses that have been proposed to play roles in development and plasticity of synaptic transmission. Our data indicate that distribution of functional AMPA receptors is tightly correlated with spine geometry and that receptor activity is independently regulated at the level of single spines.

Compensatory responses of left atrial conduit flow to atrial fibrillation with acute myocardial infarction in a canine model

The aim of this study was to examine the interaction of acute atrial fibrillation (Af) and acute myocardial infarction (AMI) on left atrial (LA) and left ventricular (LV) filling in atrioventricular (A-V) sequential paced, open chest, anesthetized dogs. Left atrial conduit function was determined from pulmonary venous flow (PVF) and detailed analysis of early diastolic flow with the use of micromanometers and transmitral Doppler echocardiography. We studied 8 dogs with regular ventricular rates to avoid the confounding effect of ventricular arrhythmia in Af. In the control stage, Af increased the diastolic PVF volume to the left atrium compared with that during regular A-V pacing (from 0.58 +/- 0.11 mL/beat to 0.70 +/- 0.13 mL/beat, P <.05), as a compensatory response to the impaired systolic PVF volume (from 0.56 +/- 0.12 mL/beat to 0.41 +/- 0.11 mL/beat, P <.05). As a result, cardiac output was maintained. However, in the AMI stage, Af decreased cardiac output (from 0.95 +/- 0.32 L/min to 0.80 +/- 0.23 L/min, P <.05 versus AMI with A-V pacing), and decreased diastolic PVF volume (from 0.46 +/- 0.13 mL/beat to 0.33 +/- 0.14 mL/beat, P <.05 versus AMI with A-V pacing). These changes were associated with a prolonged LV isovolumic pressure decay rate. Our study demonstrates that Af does not affect cardiac output in the setting of normal LV function at a controlled ventricular rate because enhanced LA conduit flow compensates for impaired LA reservoir function. In contrast, in the setting of AMI, the compensatory response to Af is attenuated because of abnormal LV relaxation, resulting in a decrease in cardiac output.

The importance of pulmonary venous flow measurement for evaluating left ventricular end-diastolic pressure in patients with coronary artery disease in the early stage of diastolic dysfunction

Transmitral flow pattern assessed by pulsed Doppler echocardiography is widely used to evaluate left ventricular end-diastolic pressure (LVEDP). A restrictive mitral flow pattern is well recognized as a finding of severely elevated LVEDP. On the other hand, an abnormal relaxation pattern can be interpreted many ways. For example, some patients who display an abnormal relaxation pattern have a mild impairment of left ventricular (LV) relaxation as a result of aging, and others have severely impaired LV diastolic function. To evaluate LVEDP in patients with abnormal relaxation mitral filling patterns, we studied 55 patients who had coronary artery disease with abnormal relaxation pattern who underwent elective cardiac catheterization. We recorded the transmitral and pulmonary venous flow velocity curves and measured the duration of the mitral A wave (MAd) and pulmonary venous reversal wave during atrial contraction (PAd). Positive correlations were found between PAd and LVEDP (r = 0.65, P <.01) and between PAd-MAd and LVEDP (r = 0.7, P <.0001); however, MAd was not significantly correlated with LVEDP. In conclusion, PAd must be measured for an accurate evaluation of LV end-diastolic pressure in patients with an abnormal relaxation pattern in the transmitral flow velocity curve.

Phosphorylation of proteins and apoptosis induced by c-Jun N-terminal kinase1 activation in rat cardiomyocytes by H(2)O(2) stimulation

Cytokines and various cellular stresses are known to activate c-Jun N-terminal kinase-1 (JNK1), which is involved in physiological function. Here, we investigate the activation of JNK1 by oxidative stress in H9c2 cells derived from rat cardiomyocytes. H(2)O(2) (100 microM) significantly induces the tyrosine phosphorylation of JNK1 with a peak 25 min after the stimulation. The amount of JNK1 protein remains almost constant during stimulation. Immunocytochemical observation shows that JNK1 staining in the nucleus is enhanced after H(2)O(2) stimulation. To clarify the physiological role of JNK1 activation under these conditions, we transfected antisense JNK1 DNA into H9c2 cells. The antisense DNA (2 microM) inhibits JNK1 expression by 80% as compared with expression in the presence of the sense DNA, and significantly blocks H(2)O(2)-induced cell death. Consistent with the decrease in cell number, we detected condensation of the nuclei, a hallmark of apoptosis, 3 h after H(2)O(2) stimulation in the presence of the sense DNA for JNK1. The antisense DNA of JNK1 inhibits the condensation of nuclei by H(2)O(2). Under these conditions, the H(2)O(2)-induced phosphorylation of proteins with molecular masses of 55, 72, and 78 kDa is blocked by treatment with the antisense DNA for JNK1 as compared with the sense DNA for JNK1. These findings suggest that JNK1 induces apoptotic cell death in response to H(2)O(2), and that the cell death may be involved in the phosphorylations of 55, 72, and 78 kDa proteins induced by JNK1 activation.

[Transverse myelopathy with renovascular hypertension caused by fibromuscular dysplasia]

An 18-year-old woman developed subacute transverse myelopathy with renovascular hypertension, hyperlipidemia, and proteinuria. Spinal magnetic resonance imaging(MRI) showed an intra-spinal cord lesion with severe spinal cord swelling at the C 2-Th 2 level. Increased plasma and cerebrospinal fluid interleukin-8(IL-8) levels and the presence of serum antineutrophil cytoplasmic antibody(ANCA) suggested the existence of an ischemic lesion due to vasculitis. Administration of corticosteroids ameliorated the clinical symptoms and MRI findings. Renovascular angiogram revealed the presence of fibromuscular dysplasia(FMD) at the left renal artery but no malformation was found at the cervical arteries. We discussed the possibility of relationships between myelopathy, FMD, IL-8, and ANCA.

Local implantation of autologous bone marrow cells for therapeutic angiogenesis in patients with ischemic heart disease: clinical trial and preliminary results

A new therapy for severe ischemic heart disease has been developed; therapeutic angiogenesis induced by the local implantation of autologous bone marrow cells (BMC). After confirming that no detrimental changes were induced by this treatment in a canine heart model, a clinical trial was commenced in 1999. Thus far, 5 patients have been given this new treatment concomitant with coronary artery bypass grafting and all have been followed up for at least 1 year. Autologous BMC were implanted into the ungraftable area and postoperative cardiac scintigraphy showed specific improvement in coronary perfusion in 3 of the 5 patients. Postoperative chest radiography, electrocardiography, echocardiography and blood tests did not reveal any detrimental changes. In conclusion, this new therapy appears to be safe and could provide a treatment option for patients with otherwise untreatable ischemic heart disease.

[Feasibility of early tapering and discontinuation of cyclosporine to intensify the graft-versus-leukemia effect in patients with advanced hematologic neoplasms]

Twenty patients with advanced hematological malignancies at high risk of relapse who had each received a bone marrow transplant from a matched sibling were registered between October 1996 and January 2000. Cyclosporine (CSP) was tapered on day 40 and stopped on day 50 in 10 patients without prior grade II-IV acute graft-versus-host disease (GVHD), relapse or active infection. These patients were eligible for early tapering of CSP. Although grade II/III acute GVHD was observed in three patients and chronic GVHD in eight patients after CSP tapering, no patients died of GVHD. Three patients died due to disease relapse and one patient died of idiopathic interstitial pneumonia while in remission. The probability of event-free survival at 2 years was 60%. These result indicate that early tapering and withdrawal of CSP is feasible and may provide a graft-versus-leukemia effect in patients with advanced leukemia.

New method of on-line quantification of regional wall motion with automated segmental motion analysis

We have recently developed an automated segmental motion analysis (A-SMA) system, based on an automatic "blood-tissue interface" detection technique, to provide real-time and on-line objective echocardiographic segmental wall motion analysis. To assess the feasibility of A-SMA in detecting regional left ventricular (LV) wall motion abnormalities, we performed 2-dimensional echocardiography with A-SMA in 13 healthy subjects, 22 patients with prior myocardial infarction (MI), and 9 with dilated cardiomyopathy (DCM). Midpapillary parasternal short-axis and apical 2- and 4-chamber views were obtained to clearly trace the blood-tissue interface. The LV cavity was then divided into 6 wedge-shaped segments by A-SMA. The area of each segment was calculated automatically throughout a cardiac cycle, and the area changes of each segment were displayed as bar graphs or time-area curves. The systolic fractional area change (FAC), peak ejection rate (PER), and filling rate (PFR) were also calculated with the use of A-SMA. In the control group, a uniform FAC was observed in real time among 6 segments in the short-axis view (60% +/- 10% to 78% +/- 9%), or among 5 segments in either the 2-chamber (59% +/- 12% to 75% +/- 16%) or 4-chamber view (58% +/- 13% to 72% +/- 12%). The variations of FAC, PER, and PFR were obviously decreased in infarct-related regions in the MI group and were globally decreased in the DCM group. We conclude that A-SMA is an objective and time-saving method for assessing regional wall motion abnormalities in real time. This method is a reliable new tool that provides on-line quantification of regional wall motion.

Ischemic preconditioning attenuates cardiac sympathetic nerve injury via ATP-sensitive potassium channels during myocardial ischemia

BACKGROUND

During myocardial ischemia, massive norepinephrine (NE) is released from the cardiac sympathetic nerve terminals, reflecting the sympathetic nerve injury. A brief preceding ischemia can reduce infarct size; this is known as ischemic preconditioning (PC). The effect of PC on sympathetic nerves, however, including its underlying mechanisms in dog hearts, has remained unclear. Thus, this study was designed to elucidate whether the activation of ATP-sensitive potassium (K(ATP)) channels is involved in the mechanism of cardiac sympathetic nerve protection conferred by PC.

METHODS AND RESULTS

Interstitial NE concentration was measured by the in situ cardiac microdialysis method in 45 anesthetized dogs. Five minutes of ischemia followed by 5 minutes of reperfusion was performed as PC. In the controls, the dialysate NE concentration (dNE) increased 15-fold after the 40-minute ischemia. PC decreased dNE at 40-minute ischemia by 59% (P<0.01), which was reversed by glibenclamide. A K(ATP) channel opener, nicorandil (25 microg. kg(-1). min(-1) IV), decreased dNE at 40 minutes of ischemia by 76% (P<0.01), which was also reversed by glibenclamide. During the PC procedure, no significant increase in dNE was detected, even with the uptake-1 inhibitor desipramine.

CONCLUSIONS

Cardiac sympathetic nerve injury during myocardial ischemia was attenuated by PC via the activation of K(ATP) channels, but the trigger of the PC effect is unlikely to be NE release in dog hearts.

Anthracycline-induced cardiomyopathies evaluated by tissue Doppler tracking system and strain rate imaging

OBJECTIVES

Anthracycline cardiotoxicity is known to occur from the subendocardial side of the left ventricular wall. Recent advances of tissue Doppler echocardiography may allow the evaluation of anthracycline cardiotoxicity by dividing the left ventricular wall into the subendocardial half and subepicardial half. The present study assessed the feasibility using the tissue Doppler echo tracking system (M-mode) and myocardial strain rate imaging (B-mode) to noninvasively detect anthracycline cardiotoxicity.

METHODS

The tissue Doppler echo tracking system (M-mode) was used to measure systolic thickening of the subendocardial layer (delta Endo), subepicardial layer (delta Epi), and whole wall (delta Total) of the left ventricular posterior wall in 41 normal subjects and three groups of patients receiving anthracycline: 34 patients in the low dose group, 19 in the middle dose group, and 12 in the high dose group. Strain rate is the spatial gradient of local velocities, reflecting local compression and expansion rates not affected by overall heart motion. Myocardial strain rate imaging (B-mode) was used in 25 normal subjects, 9 patients in the low dose group, and 10 patients in the high dose group. The ratio of peak systolic strain rate of subendocardium to that of subepicardium (peak strain rate endo/epi), and the ratio of integrated strain rate during ejection time of subendocardium to that of subepicardium (integrated strain rate endo/epi) were measured.

RESULTS

Tissue Doppler echo tracking system (M-mode) measurement of delta Endo/delta Epi showed the most distinct difference and the least overlap of the data between normal subjects and patients, whereas delta Total failed to show significant differences. Myocardial strain rate imaging (B-mode) measurement of integrated strain rate endo/epi showed the most distinct difference and the least overlap of the data between normal subjects and patients, but ejection fraction failed to show statistically significant differences.

CONCLUSIONS

These methods are highly sensitive tools for monitoring anthracycline cardiotoxicity.

Direct closure of ostium primum defect in the repair of atrioventricular septal defect

BACKGROUND

Patch closure is generally performed for atrial septation of an atrioventricular septal defect. We recently developed a new surgical technique for repairing atrioventricular septal defects that avoids the use of any patch material for closing the atrial septal defect. We report our experience with this procedure.

METHODS

Seven patients (complete type: 5, partial type: 2) underwent this new operation. The diameters of the atrial septal defects were measured by transesophageal echocardiography. The preoperative electrocardiograms were compared with those taken after the operations.

RESULTS

Diameters of the atrial defects ranged from 3 to 10 mm. Electrocardiograms before and after the operations did not change. No significant atrioventricular valve regurgitation and no residual shunts were detected by postoperative echocardiography.

CONCLUSIONS

This method simplifies the repair of atrioventricular septal defects. In the short-term results, no arrhythmia and no valve regurgitation was seen.

[Successful second transplant from one-locus HLA-mismatched unrelated donor for graft rejection following initial transplant from another unrelated donor in a patient with chronic myelogenous leukemia]

We report a patient with chronic myelogenous leukemia who received a second transplant from a one-locus HLA-mismatched unrelated donor after rejection of an initial bone marrow graft. For the first transplant, HLAs were fully matched, conditioning with busulfan + cyclophosphamide (CY) was applied, and cyclosporin A + short-term methotrexate (sMTX) was used for prophylaxis against GVHD. A complete chimera was not obtained, and the graft was rejected on day 122. For the second transplant, there was a one-HLA locus (DR) mismatch, conditioning was done with total body irradiation + cytarabine + CY, and GVHD prophylaxis consisted of FK506 + sMTX. Engraftment was obtained on day 27, and no graft failure was occurred at the time of writing. This case suggests that strong immunosuppression may have prevented rejection of the second bone marrow graft.

Bronchiolitis obliterans organizing pneumonia (BOOP) with suspected liver graft-versus-host disease after allogeneic bone marrow transplantation

We report on a patient with chronic myelogenous leukemia who developed bronchiolitis obliterans organizing pneumonia (BOOP) after allogeneic bone marrow transplantation (BMT). A 19-year-old Japanese male complained of dry cough and dyspnea 7 months after BMT. The chest X-ray and computed tomography revealed patchy infiltrates bilaterally. Lung function test, lung biopsy and bronchoalveolar lavage were consistent with the diagnosis of BOOP. The patient also suffered from suspected graft-versus-host disease (GVHD) of the liver, after discontinuation of cyclosporine. Furthermore, prednisolone proved effective against the BOOP and the liver dysfunction. These findings indicate that BOOP is a possible pulmonary manifestation of chronic GVHD, and that immunological mechanisms may have effected the onset of BOOP after BMT in this case.

Glycerol affects vestibular evoked myogenic potentials in Meniere's disease

OBJECTIVES

to show that abnormal vestibular evoked myogenic potentials on the sternocleidomastoid muscle (SCM) in patients with unilateral Meniere's disease are caused by endolymphatic hydrops.

SUBJECTS

six normal volunteers and 17 patients with unilateral Meniere's disease were examined.

METHODS

click-evoked myogenic potentials were recorded with surface electrodes over each SCM. Responses evoked by clicks recorded after oral administration of glycerol (1.3 g/kg body weight) were compared with those recorded before administration.

RESULTS

the change rate of the p13-n23 amplitude was calculated. The mean+standard deviation (S.D.) of the change rate was 3.52+14.6% in normal subjects. On the unaffected side of patients the change rates were within the normal range (within the mean+/-2S.D.) in 13 patients, and three ears showed significant decrease. Only one ear showed significant increase. On the affected side, five ears showed significant increase of the amplitude while two ears showed significant decrease after oral administration of glycerol. Effects on evoked myogenic potentials were independent of those on pure tone hearing.

CONCLUSION

vestibular evoked myogenic potentials in some patients with unilateral Meniere's disease were improved by oral administration of glycerol. This result suggests that abnormal vestibular evoked myogenic potentials in patients with unilateral Meniere's disease could result from endolymphatic hydrops.

Orphan G protein-coupled receptor, GPR41, induces apoptosis via a p53/Bax pathway during ischemic hypoxia and reoxygenation

Orphan receptors that couple to G protein without known ligands are considered to relate directly to drug discovery. Here, we examine the expression of various orphan receptors in H9c2 cells during ischemic hypoxia and reoxygenation. Among orphan receptors examined, the level of G protein-coupled receptor 41 (GPR41) mRNA increases significantly, with a peak at 2 h after reoxygenation, and recovers to the control level by 3 h after reoxygenation. The level of glyceraldehyde-3-phosphate dehydrogenase mRNA used as an internal control remains almost constant. The levels of c-fos and c-jun mRNA increase significantly with ischemic hypoxia and reoxygenation. The transfection of GPR41 into H9c2 cells results in a significant decrease in cell number, with DNA fragmentation observed by in vitro and in situ assay. The amount of p53 protein increases significantly in the nuclei of cells expressing GPR41, accompanying an increase in the transcriptional activity of p53. Consistent with the activation of p53, the level of bax mRNA is significantly increased, which leads to an increase in Bax protein. Furthermore, the expression of a deletion mutant of a GPR41, which lacks the G protein binding site and shows an attenuation of intracellular phosphorylation signals to H9c2 cells, inhibits cell death and the increase in p53 protein within 24 h after reoxygenation. These observations demonstrate that GPR41 is a novel receptor that activates p53 leading to apoptosis during reoxygenation after ischemic hypoxia in H9c2 cells. We have designated GPR41 as the hypoxia-induced apoptosis receptor, HIA-R.

The induction of angiogenesis by the implantation of autologous bone marrow cells: a novel and simple therapeutic method

BACKGROUND

Bone marrow contains many kinds of primitive cells that could differentiate to endothelial cells and secrete several growth factors. In the current study, we attempted to induce therapeutic angiogenesis by implanting autologous bone marrow cells (BMCs) and using a rat ischemic hind limb model.

METHODS

BMCs were prepared by removing red blood cells. A rat ischemic hind limb model was made by the ligation of the left femoral artery and its branches. BMCs were injected into 7 points of the ischemic muscles. To assess angiogenesis, a microangiogram, laser Doppler, and histologic evaluation were performed after the surgical procedure.

RESULTS

A microangiogram and histologic evaluation showed that angiogenesis was significantly induced in the ischemic hind limb by the implantation of BMCs. Laser Doppler imaging analysis showed that blood flow was significantly increased after implantation of BMCs. Some implanted BMCs were stained positively with CD31 and vascular endothelial-cadherin (VE-cadherin), which might have been incorporated into the vasculature. The condition of ischemia caused an elevation in the level of basic fibroblast growth factor in the ischemic muscle and also in interleukin-1beta derived from the implanted BMCs, which might contribute to angiogenesis.

CONCLUSION

These findings indicate that autologous bone marrow implantation may be a novel and simple method for inducing therapeutic angiogenesis.

Appropriate dosing of pilsicainide hydrochloride in patients on hemodialysis

Appropriate dosing of pilsicainide hydrochloride, an anti-arrhythmic drug excreted via the kidney, was investigated in patients on dialysis. Ten chronic hemodialysis patients with coexisting severe palpitation of supraventricular premature contractions (SVPC) were treated with 25 mg of pilsicainide hydrochloride before dialysis. All of their plasma concentrations were maintained within the therapeutic range and their mean dialysis rate was 32%. After 2 weeks, 7 patients were followed with consecutive daily dose treatment. In 3 of them, the dosage was returned to the single pre-dialysis administration because of the elevated plasma concentration reaching the toxic range 1 month after the start of administration. The dose schedule was maintained, and plasma pilsicainide concentrations remained within the therapeutic range during the 6-month follow-up. No abnormal findings were found in any parameters of electrocardiography, echocardiography or biochemistry. The number of SVPC diminished > 90% compared to the pretreatment level.

Immune reconstitution assessed during five years after allogeneic bone marrow transplantation

Immune reconstitution is an important component of successful allogeneic bone marrow transplantation. Immune reconstitution was evaluated for 5 years after transplantation. While the number of CD8+ T cells and CD56+ cells recovered early post transplantation, a low number of CD4+ and CD4+ CD45RA+ T cells and reversal of the CD4/CD8 ratio continued up to 5 years. Although early recovery of IgG and IgM was seen at day 100 post transplantation, serum concentration of IgA was below the normal range at 6 months and increased gradually up to 5 years. Development of acute GVHD did not affect the numbers of CD4+, CD8+, CD4+ CD45RA+ and CD4+ CD29+ T cells, but the number of CD56+ cells in patients who developed grades II-IV acute GVHD was low. The number of CD4+ CD29+ T cells had a tendency to be higher in the patients with extensive chronic GVHD than in those without chronic GVHD 2 years after transplantation whereas the number of CD4+ CD45RA+ T cells was low in spite of the absence of chronic GVHD. Serum concentration of IgA was lower in patients with extensive chronic GVHD than in those without chronic GVHD at 180 days. The number of CD4+ CD45RA+ cells in 10-19-year-old patients was higher than that in 40-49-year-old patients. Response to the Con A and PHA in 10-19-year-old patients was higher than that in older patients at 1 and 2 years. There was no significant difference in the ability of immune reconstitution between related transplant recipients and unrelated transplant recipients. These results suggest that chronic GVHD and age of patients affected immune reconstitution post transplant.

[RyR-bound FKBP12.6 and the modulation]

In the pathogenesis of cardiac dysfunction in heart failure, a decrease in the activity of the sarcoplasmic reticulum (SR) Ca(2+) -ATPase is believed to be a major determinant. Recently, a novel mechanism of cardiac dysfunction in heart failure has been reported on the basis of the following findings:1) PKA hyperphosphorylation of RyR causes a dissociation of FKBP12.6 from RyR, resulting in the abnormal single-channel properties (increased Ca(2+) sensitivity for activation and elevated channel activity associated with destabilization of RyR (Marx et al, Cell 101:365, 2000), 2) a prominent abnormal Ca(2+) leak occurs through RyR, following a partial loss of RyR-bound FKBP12.6 and the resultant conformational change in RyR (Yano M et al, Circulation 102:2131, 2000). This abnormal Ca(2+) leak might possibly cause Ca(2+) overload and consequent diastolic dysfunction, as well as systolic dysfunction.

[Accuracy and usefulness of ultraportable hand-carried echocardiography system]

OBJECTIVES

The diagnostic accuracy and usefulness of an ultraportable hand-carried echocardiography system were investigated for assessing ventricular systolic function and severity of mitral valvular regurgitation.

METHODS

The study population consisted of 77 consecutive patients (47 men, 30 women, mean age 63 +/- 15 years). Left ventricular end-diastolic dimension, left ventricular end-systolic dimension and left ventricular ejection fraction were measured using the hand-carried echo system and the data were compared with measurements by the conventional echocardiography system using simple linear regression analysis. Left ventricular wall motion was compared between the systems using a 16-segment model recommended by the American Society of Echocardiography. Severity of mitral regurgitation was assessed by the distance of the regurgitant signal in the left atrium.

RESULTS

Left ventricular end-diastolic dimension, left ventricular end-systolic dimension and left ventricular ejection fraction showed good correlations between hand-carried and conventional echo systems (r = 0.94, 0.91 and 0.81, respectively; each p < 0.0001). The accuracy for assessing left ventricular wall motion was 94% (449 of 480 segments). The echo systems also showed the same degree of diagnostic accuracy for severity of mitral regurgitation.

CONCLUSIONS

The hand-carried echo system provides accurate assessment of left ventricular function and mitral regurgitation simular to conventional echo machines.

Effects of cardioplegic arrest and reperfusion on rabbit cardiac ryanodine receptors

Calcium overload is considered to be a primary contributor to ischemia-reperfusion injury. Cardiac sarcoplasmic reticulum (SR), the main regulator of intracellular Ca2+ concentration under normal conditions, is a target for ischemic myocardial injury. The ryanodine receptor (RyR) is the SR Ca2+ release channel. Previous reports have shown that a reduction in RyR activity during global myocardial ischemia correlates with concomitant myocardial dysfunction. Crystalloid cardioplegia, a technique for myocardial protection during heart operations, reduces Ca2+ accumulation during global ischemia. Hence, the effects of cardioplegia on RyR in isolated rabbit hearts was investigated. The study also compared [3H] ryanodine binding before ischemia (control group), after 30 min of ischemia (either global ischemia (GI group) or cardioplegic arrest (CA group)), and after 20 min of reperfusion. The GI group, but not the CA group, showed a significant reduction in the maximum number of binding sites (Bmax) for RyR compared with the control group (Control vs GI group: after ischemia, 1.33+/-0.27 vs 0.83+/-0.12 pmol/mg protein, p<0.05; after reperfusion, 1.33+/-0.27 vs 0.80+/-0.08 pmol/mg protein; p<0.05). CA group: after ischemia, 1.22+/-0.20 pmol/mg protein; after reperfusion, 1.15+/-0.28 pmol/mg protein). The affinity (Kd) values for [3H] ryanodine binding were not different among the 3 groups at any point. The preservation of RyR numbers during cardioplegia correlated with the concomitant preservation of cardiac functions. The results indicate that number of functional RyR was much better preserved during cardioplegia than during global ischemia. It is postulated that cardioplegia-induced protection of cardiac RyR may result in the protection of SR function during ischemia-reperfusion.

Influence of timing and magnitude of arterial wave reflection on left ventricular relaxation

The influence of timing and magnitude of arterial wave reflection (WR) on afterload-dependent relaxation was evaluated in patients with a variety of heart diseases (group 1, age < 30 yr; group 2, age > 40 yr) and in dogs. While both femoral arteries were compressed (FC), WR returned just after the dicrotic notch (early diastole) in group 1 but before the dicrotic notch (late systole) in group 2. The time constant of the left ventricular pressure decay (tau) was shortened during FC in group 1, whereas it was prolonged in group 2. In dogs, a constriction of the thoracic aorta induced a late systolic augmentation of WR with a prolongation of tau (cf. group 2), whereas constriction of the lower abdominal aorta induced an early diastolic augmentation of WR with a shortening of tau (cf. group 1). With aortic constriction, coronary flow increased, and there was a close correlation between the peak change in backward aortic pressure and that in coronary flow regardless of the timing of WR. Thus the time at which WR returns during the cardiac cycle may have an important effect on left ventricular relaxation and coronary flow.

Effect of low-intensity warfarin therapy on left atrial thrombus resolution in patients with nonvalvular atrial fibrillation: a transesophageal echocardiographic study

The presence of left atrial thrombus (LAT) is associated with an increased risk of embolic stroke. However, it has yet to be established definitively whether low-intensity warfarin therapy (INR: 1.5-2.0) can prevent LAT formation in patients with nonvalvular atrial fibrillation (NVAF). The present study analyzed the clinical and transesophageal echocardiography (TEE) features of 123 such patients to identify risk factors for LAT formation and the efficacy of prophylactic low-intensity warfarin therapy. Left atrial thrombi were found in 35 patients (28%) in whom systemic hypertension (49% vs 23%; p<0.01) and ischemic heart disease (17% vs 3%; p<0.01) were more frequent. Left ventricular ejection fraction (54+/-14% vs 60+/-11%; p<0.05), left ventricular end-diastolic dimension (51+/-7 mm vs 48+/-5 mm; p<0.05), spontaneous echo contrast (2.2+/-0.7 vs 1.4+/-0.9; p<0.01), left atrial diameter (50+/-6 mm vs 43+/-7 mm; p<0.01), left atrial appendage blood velocity (22.3+/-8.7 cm/s vs 37.2+/-21.5 cm/s; p<0.01) and the incidence of left ventricular hypertrophy (37% vs 15%; p<0.01) were also significantly different between the groups. Fourteen patients received continuous warfarin therapy (target INR: 1.5-2.0) and on the follow-up TEE study the left atrial thrombus resolved in 10 (71%). There were no thromboembolic events or major hemorrhagic complications in these patients, so it was concluded that low-intensity warfarin therapy is efficacious in treating LAT formation in patients with NVAF.

Autologous bone marrow implantation induced angiogenesis and improved deteriorated exercise capacity in a rat ischemic hindlimb model

BACKGROUND

Bone marrow possesses endothelial progenitor cells that secrete several growth factors and can contribute to the formation of new capillaries. In the present study, we investigated the extent of angiogenesis induced by implantation of autologous bone marrow cells (BMCs) in a rat ischemic hindlimb model and studied whether the increased collateral vessels can improve deteriorated physical function.

MATERIALS AND METHODS

Ischemic hindlimb was created by ligation of the femoral artery and its branches in Dark Agouti (DA) rats. BMCs (1 x 10(7)) were injected percutaneously at six points into the gastrocnemius muscle. To assess angiogenesis, histologic evaluation and microangiography were performed at 2 weeks postligation. Severity of the ischemic insult was evaluated by measuring blood flow in the adductor and gastrocnemius muscles using nonradioactive colored microspheres and by determining the femoral arteriovenous oxygen difference (AVDO(2)) at 2 weeks postligation. Running time on a motor-driven treadmill was used to represent exercise capacity.

RESULTS

The histologic evaluation and microangiogram showed that the implanted BMCs induce angiogenesis. Blood flow to the adductor muscle on the treated side in the bone marrow cell implantation (BMI) group was significantly restored to 77.3 +/- 19.3% of that of the normally perfused limb in comparison to that in control groups (P < 0.05). AVDO(2) in the BMI group significantly decreased when compared with AVDO(2) in control groups. Rats in the BMI group ran approximately 1.5 times longer than rats in control groups at 2 and 4 weeks postligation (P < 0.01).

CONCLUSIONS

Implantation of autologous BMCs induced angiogenesis and improved deteriorated exercise capacity in our rat ischemic hindlimb model.

Molecular cloning of rat transmembrane domain protein of 40 kDa regulated in adipocytes and its expression in H9c2 cells exposed to ischemic hypoxia and reoxygenation

We clone a 1230 bp complementary DNA encoding rat transmembrane domain protein of 40 kDa regulated in adipocytes (TPRA40), an orphan receptor, by reverse transcription-polymerase chain reaction using H9c2 cells derived from embryonic rat heart. The deduced amino acid sequence of rat TPRA40 consists of 369 amino acids and has a longer carboxyl terminus than that of the mouse protein. The level of TPRA40 mRNA decreases significantly throughout ischemic hypoxia and reoxygenation.

Up-regulation of inositol 1,4,5 trisphosphate receptor expression in atrial tissue in patients with chronic atrial fibrillation

OBJECTIVES

We examined whether patients with atrial fibrillation (AF) have alterations in atrial inositol 1,4,5 trisphosphate receptors (IP3 receptors).

BACKGROUND

Abnormal intracellular Ca2+ homeostasis occurs in chronic AF. The intracellular Ca2+ concentration is regulated by ryanodine and IP3 receptors. We recently reported alterations in ryanodine receptors in atrial tissue from patients in chronic AF.

METHODS

We analyzed IP3 receptor expression in the right atrial myocardium from 13 patients with mitral valvular disease (MVD) with AF (MVD/AF), five patients with MVD who had normal sinus rhythm (MVD/NSR) and eight control patients with NSR (tissue obtained during coronary artery bypass surgery). Hemodynamic and echocardiographic data were obtained preoperatively, and an immunohistochemical study was performed on atrial tissue.

RESULTS

The relative expression level of IP3 receptor protein was significantly greater in MVD/AF (0.75 +/- 0.26) than it was in MVD/NSR (0.42 +/- 0.13, p < 0.01), and both were significantly above control (0.14 +/- 0.08). The relative expression level of IP3 receptor messenger RNA was significantly greater in the MVD/AF group (0.028 +/- 0.008) than it was in the control group (0.015 +/- 0.004, p < 0.01), but patients with MVD/AF did not differ from patients with MVD/NSR (0.020 +/- 0.006). The relative expression levels of IP3 receptor protein and messenger RNA were higher in patients with left atrial dimension > or = 40 mm, pulmonary capillary wedge pressure > or = 10 mm Hg and right atrial pressure > or = 5 mm Hg. Inositol 1,4,5 trisphosphate receptors were over-expressed in the cytosol and at the nuclear envelope of atrial myocytes in MVD.

CONCLUSIONS

Since chronic mechanical overload of the atrial myocardium increased IP3 receptor expression, especially in patients with chronic AF, up-regulation of IP3 receptors may be important in modulating intracellular Ca2+ homeostasis and initiating or perpetuating AF.

Detection of fibrous cap in atherosclerotic plaque by intravascular ultrasound by use of color mapping of angle-dependent echo-intensity variation

BACKGROUND

The thickness of the fibrous cap is a major determinant in the vulnerability of atherosclerotic plaque to rupture. It has been demonstrated that intravascular ultrasound (IVUS) backscatter from fibrous tissue is strongly dependent on the ultrasound beam angle of incidence. This study investigated the feasibility of using a new IVUS color mapping technique representing the angle-dependent echo-intensity variation to determine the thickness of the fibrous cap in atherosclerotic plaque.

METHODS AND RESULTS

Nineteen formalin-fixed noncalcified human atherosclerotic plaques from necropsy were imaged in vitro with a 30-MHz IVUS catheter. The IVUS catheter was moved coaxially relative to the plaque. The images showing maximum and minimum echo intensity of the plaque surface were selected to calculate the angle-dependent echo-intensity variation. A colorized representation of the echo-intensity variation in the plaque was obtained from the 2 IVUS images. A clearly bordered area with large variation in echo intensity was revealed for each plaque surface in the colorized IVUS image. The thickness (x, mm) of this area correlated significantly with that of fibrous cap (y, mm) measured from histologically prepared sections as y=1.05x-0.01 (r=0.81, P:<0.0001). Bland-Altman analysis also supported the reliability of this method (mean difference, 0.00+/-0.10 mm).

CONCLUSIONS

This novel technique for color mapping the echo-intensity variation in IVUS provided an accurate representation of the thickness of the fibrous cap in atherosclerotic plaque. This method may be useful in assessing plaque vulnerability to rupture in atherosclerosis.

Atheromatous plaque in the distal aortic arch creating the potential for cerebral embolism during cardiopulmonary bypass

The present study evaluated the risk in cardiac patients of rupture of a plaque by a jet stream from the arch cannula. The entire thoracic aorta and cardiac function were routinely monitored by transesophageal echocardiography (TEE) in 88 adult patients who underwent coronary artery bypass surgery. The changes in the atheromatous plaque in the distal aortic arch were observed before and after cardiopulmonary bypass. Of the 88 patients, 13 were found to have preoperative atheromatous plaque at the distal aortic arch and 8 (61.5%) of them suffered plaque rupture caused by jet stream from the arch cannula. Only 1 patient experienced apparent embolic episodes manifesting as cerebral and left leg embolisms; the remaining 7 had no clinical embolic symptoms. In order to prevent atheroembolic events, attention should be paid not only to the ascending aorta, but also to the distal arch and in this regard TEE is useful for detecting atheromatous changes of the aorta.

Effects of in vivo gene transfer of fibroblast growth factor-2 on cardiac function and collateral vessel formation in the microembolized rabbit heart

The effects of gene transfer of the secreted form of fibroblast growth factor-2 (FGF-2) were tested using an adenovirus vector in the microembolized rabbit heart. Japanese white rabbits underwent an intracoronary injection of 25-microm microspheres followed by recombinant adenovirus vectors encoding a secreted form of FGF-2 (FGF group), LacZ (LacZ group), or saline (saline group). Left ventricular (LV) systolic function was serially assessed by echocardiography. Vascular density was measured at 14 days with Azan and CD31 staining. The development of collateral vessels was assessed by measuring myocardial blood flow before and after the occlusion of the left anterior descending coronary artery. Percent fractional shortening (%FS) decreased after the microembolization, and improved gradually for 14 days in the FGF group only (41+/-1% (FGF) vs 32+/-1% (LacZ), 31+/-1% (saline), p<0.01). The vascular density and myocardial collateral blood flow were significantly higher in the FGF group in comparison with other groups. Transcoronary arterial gene transfer of the secreted form of FGF-2 was beneficial for the recovery of LV systolic function and development of collateral vessels in the microembolized rabbit heart.

Heterogeneous expression of nonmuscle myosin heavy chain-B in mesangial cells of patients with Gitelman's syndrome

AIMS

It has been suggested that angiotensin II (Ang II) promotes hypertrophy and hyperplasia of mesangial cells. Nonmuscle myosin heavy chain-B (NMHC-B) and alpha-smooth muscle (SM) actin are considered to be molecular markers for phenotypic change ofproliferative mesangial cells. One of the clinical characteristics in Gitelman's syndrome (GS) is the elevation of plasma Ang II. However, little is known about the relation between Ang II and phenotypic change of mesangial cells in patients with GS. In this report, we examined the expression of NMHC-B and alpha-SM actin in mesangial cells of two GS patients.

MATERIALS AND METHODS

Plasma renin activity, and the concentrations of Ang II, 6-keto-prostaglandin F1alpha (6-keto-PGF1alpha), urinary kallikrein, and 6-keto-PGF1alpha were measured. Immunohistochemical staining of NMHC-B and alpha-SM actin in mesangial cells of GS patients was also performed.

RESULTS

Both cases of GS showed normal glomerular function, few histological abnormalities, and higher than normal plasma concentrations of renin and Ang II. Furthermore, one case showed a high urinary concentration of kallikrein and the expression of both NMHC-B and alpha-SM actin in mesangial cells. The other case showed a high urinary concentration of 6-keto-PGF1alpha but not kallikrein and without the expression of NMHC-B and alpha-SM actin.

CONCLUSION

Not only plasma kinin-kallikrein and prostaglandins, but the renal expression of NMHC-B and alpha-SM actin may be variable in different patients with GS.

[Complete cytogenetic response obtained with unrelated donor lymphocyte infusion for relapse of chronic myeloid leukemia in blastic crisis after allogeneic bone marrow transplantation]

A 35-year-old man with chronic myeloid leukemia (CML) in blastic crisis (BC) received an allogeneic bone marrow transplant from an unrelated donor in October 1998 after three cycles of chemotherapy. BC relapse developed on day 349 after transplantation. After one cycle of chemotherapy and treatment with interferon, the patient received donor lymphocyte infusion (DLI), and this resulted in a complete cytogenetic response 21 days later. Grade III acute graft-versus-host disease developed on day 25 after DLI, but this was resolved after administration of prednisolone. Disease relapse occurred at extramedullary sites on day 162 after DLI, and the patient died of sepsis after receiving chemotherapy. This case illustrates that unrelated DLI can induce remission successfully in patients with relapse of CML in BC through a graft-versus-leukemia effect.

Enhancement of Rho/Rho-kinase system in regulation of vascular smooth muscle contraction in tachycardia-induced heart failure

OBJECTIVE

The Rho/Rho-kinase system regulates Ca(2+) sensitivity in vascular smooth muscle. A new drug, Y-27632, specifically inhibits Rho-kinase and hence decreases the phosphorylation of myosin light chain, thus reducing contraction. Here, we compare the effects of Y-27632 and nifedipine on the vasoconstrictor response of the femoral artery in heart failure.

METHODS

Heart failure (HF) was produced by chronic rapid RV pacing (250 bpm, 28 days, six dogs). Indo1-AM was loaded into endothelium-denuded femoral artery segments for measuring intracellular [Ca(2+)]. Tension and changes in intracellular [Ca(2+)] [the change in the ratio (418 nm/468 nm) of Indo1 fluorescence (F(ratio))] were simultaneously measured in Krebs-Ringer solution.

RESULTS

In HF: (i) norepinephrine (10 microM) produced greater tension (784+/-52 g/cm(2)) than in control (502+/-64 g/cm(2)) despite a similar increase in F(ratio), indicating increased Ca(2+) sensitivity in vascular smooth muscle; (ii) nifedipine attenuated this enhanced response by only a maximum of 27% at 1 micromol/l with a 56% reduction in F(ratio); (iii) Y-27632 attenuated it by a maximum of 80% at 100 micromol/l without a significant change in F(ratio); (iv) RhoA protein and mRNA expression levels in the femoral artery were up-regulated by +110% and +56%, respectively, while those of Rho-kinase were unchanged.

CONCLUSIONS

The Ca(2+)-sensitizing mechanism involving the Rho/Rho-kinase system may be deeply involved in the enhanced arterial vasoconstriction seen in HF. Since Y-27632 attenuated this response in small arteries, it shows potential as a novel, potent vasodilator for the treatment of HF.

Severe cardiac toxicity in hematological stem cell transplantation: predictive value of reduced left ventricular ejection fraction

Eighty patients receiving hematological stem cell transplantation (HCT) with a preparative regimen consisting of total body irradiation (12.5 Gy), cyclophosphamide (4000 or 4500 mg/m2), and thiotepa (400 mg/m2) were evaluated for the development of cardiac toxicity. Patients in whom the pretransplant cumulative dose of anthracycline was more than or equal to 300 mg/m2 showed a lower left ventricular ejection fraction (EF) before HCT compared to patients with less than 300 mg/m2 (0.61 +/- 0.09 vs 0.67 +/- 0.06, P = 0.0010). Patients who had undergone more than or equal to six courses of chemotherapy showed a decreased EF before HCT compared to those after less than six courses (0.67 +/- 0.05 vs 0.63 +/- 0.09, P = 0.03). Three of seven patients (43%) whose pretransplant EF had been less than or equal to 0.55 developed severe cardiac toxicity, characterized by congestive heart failure (CHF) compared with none of 83 patients (0%) whose pretransplant EF had been more than 0.55 (P = 0.00026). Of the three patients who developed severe cardiac toxicity, two were given more than 300 mg/m2 of cumulative anthracycline and underwent 23 courses and six courses of chemotherapy, while the other patient received only two courses of chemotherapy with a total dose of 139 mg/m2 of anthracycline. These results indicate that an increased cumulative dose of anthracycline and number of chemotherapy treatments are correlated with a decrease of the EF and that the EF before HCT is useful for predicting the risk of cardiac complications for recipients who have received chemotherapy.

Expression and anticoagulant function of the endothelial cell protein C receptor (EPCR) in cancer cell lines

Induction of procoagulant factors in malignant cells is considered to be the major cause of coagulation disorders in cancer. Thrombomodulin (TM), a negative regulator of coagulation was also found to be expressed in cancer cells. We report here evidence for another anticoagulant, the endothelial cell protein C receptor (EPCR), in cancer cells. EPCR was detected in several cell lines derived from various types of cancer. Significant levels of protein C (PC) activation were detected only with cell lines expressed both EPCR and TM. Anti-EPCR monoclonal antibodies (mAbs) specifically inhibited the activation. Thus, EPCR function appears to be important for PC activation by cancer cells. In addition, we detected EPCR expression in tumor cells from breast cancer patients, with an extremely high frequency. EPCR function may contribute to progression or pathogenesis of some types of cancer, and may explain the complexity of coagulopathy in cancer patients.

Predominant inner-half wall thickening of left ventricle is attenuated in dilated cardiomyopathy: an application of tissue Doppler tracking technique

The importance of the inner half (IH) of the left ventricular (LV) wall has been reported in hearts that contract normally. However, it is difficult to verify this fact in an in vivo human heart with clinical echocardiography. By using a recently developed tissue Doppler tracking technique, we could assess the systolic wall thickening of the IH and outer half (OH) of the LV wall in 11 normal and 7 dilated cardiomyopathic hearts. Percent wall thickening and the fractional contribution of the IH and OH to the transmural wall thickening were calculated. In healthy subjects, percent wall thickening of the IH, OH, and transmural wall of the left ventricle were 75.8% +/- 24.1%, 39.4% +/- 14.4% (P <.001 versus IH), and 57.6% +/- 17.6%, respectively. In patients with dilated cardiomyopathy, those values were 31.3% +/- 17.1%, 31.2% +/- 20.1% (not significant versus IH), and 31.2% +/- 16.5%, respectively. On the other hand, the fractional contributions of the IH and OH were 66.2% +/- 7.7% and 33.8% +/- 7.7% (P &lt.01 versus IH) in healthy subjects and 50.5% +/- 11.8% and 49.5% +/- 11.8% (not significant versus IH) in patients with dilated cardiomyopathy. Specifically, the IH contributed to the transmural wall thickening nearly twice as much as the OH did in healthy subjects, however, the predominance of IH contribution was attenuated in dilated cardiomyopathy. The tissue Doppler tracking technique is useful in assessing the IH and OH LV wall thickening separately in the clinical situation.

Characterization of T cell receptor beta chains of accumulating T cells in chronic ongoing myocarditis demonstrated by heterotopic cardiac transplantation in mice

Autoimmne mechanisms have been implicated in the pathogenesis of chronic ongoing mycarditis. An earlier study of murine chronic ongoing myocarditis reported that infiltrating T cells and macrophages were prominent in the normal donor heart, in a heterotopic cardiac transplantation model. It was demonstrated that myocarditis was transferred to a normal heart transplanted into a mouse with chronic myocarditis. The present study investigated an autoimmune link to the pathogenesis of chronic ongoing myocarditis by analyzing the T cell clonalities in the model. To characterize the accumulating T cells in the donor heart, the T cell receptor beta genes (TCRBG) were amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) from mRNA in the donor hearts and accumulating TCRBG clonotypes were contrasted with those from recipient hearts. Inbred 3-week-old A/J mice were inoculated intraperitoneally with Coxsackievirus B3 (Nancy strain), 2 x 10(4) PFU, and housed for more than 60 days. Normal A/J mouse hearts were transplanted into the same strain of mice without myocarditis, as well as into the mice with chronic ongoing myocarditis. Both recipient and donor hearts were evaluated histologically 2 weeks after the transplantation. TCRBG were amplified by RT-PCR from mRNA of recipient and donor hearts and spleens. The specific accumulating TCRBG clonotypes were identified by their single strand conformation polymorphism. Multiple clonotypic accumulations occurred in the donor heart after cardiac transplantation. Distinct oligoclonal accumulation of TCR Vbeta1, 10, and 13 T cells was found in both recipient and donor hearts in 3 of 4 mice. Moreover, these clonotypes were not observed in spleen cells of the recipient mice. T specific cells expanding clonotypes of TCRBG are responsible for transferring myocarditis to the donor heart. An autoimmune response may, therefore, play a key role in the progression of chronic ongoing myocarditis.

[Sequential analysis of p210- and p190-bcr-abl by RT-PCR after allogeneic bone marrow transplantation for p210/p190-bcr-abl double positive acute lymphoblastic leukemia]

In patients with both p210-bcr-abl (p210) and p190-bcr-abl (p190)-positive acute lymphoblastic leukemia, the number of p190 transcripts is lower than that of p210 transcripts. It is speculated that the p190 transcript occurs as a consequence of alternative splicing or missplicing events in the BCR gene. Four patients with both p210- and p190-positive acute lymphoblastic leukemia were studied for expression of p210 and p190 by RT-PCR before and after allogeneic bone marrow transplantation. p190 negativity was documented in all four patients, followed by p210 negativity one to two months later in three patients. These results suggest that negativity for p190 indicates an ongoing decrease in the small number of residual leukemic cells. In one patient p190 appeared transiently in spite of prolonged negativity for p210 18 months after bone marrow transplantation. We conclude that analysis of p210 and p190 is useful for following up patients with both p210- and p190-positive acute lymphoblastic leukemia.

Eicosapentaenoic acid (EPA) induces Ca(2+)-independent activation and translocation of endothelial nitric oxide synthase and endothelium-dependent vasorelaxation

Eicosapentaenoic acid (EPA), but not its metabolites (docosapentaenoic acid and docosahexaenoic acid), stimulated nitric oxide (NO) production in endothelial cells in situ and induced endothelium-dependent relaxation of bovine coronary arteries precontracted with U46619. EPA induced a greater production of NO, but a much smaller and more transient elevation of intracellular Ca(2+) concentration ([Ca(2+)]i), than did a Ca(2+) ionophore (ionomycin). EPA stimulated NO production even in endothelial cells in situ loaded with a cytosolic Ca(2+) chelator 1,2-bis-o-aminophenoxythamine-N',N',N'-tetraacetic acid, which abolished the [Ca(2+)]i elevations induced by ATP and EPA. The EPA-induced vasorelaxation was inhibited by N(omega)-nitro-L-arginine methyl ester. Immunostaining analysis of endothelial NO synthase (eNOS) and caveolin-1 in cultured endothelial cells revealed eNOS to be colocalized with caveolin in the cell membrane at a resting state, while EPA stimulated the translocation of eNOS to the cytosol and its dissociation from caveolin, to an extent comparable to that of the eNOS translocation induced by a [Ca(2+)]i-elevating agonist (10 microM bradykinin). Thus, EPA induces Ca(2+)-independent activation and translocation of eNOS and endothelium-dependent vasorelaxation.

Improvement of afterload mismatch of left atrial booster pump function with positive inotropic agent

OBJECTIVES

The objective of this study was to examine the hypothesis that a positive inotropic agent improves left ventricular (LV) filling during left atrial (LA) contraction in the presence of markedly elevated LV filling pressure.

BACKGROUND

In patients with old myocardial infarction (MI), an increase in the operational LV chamber stiffness reduces LV filling during the LA contraction, resulting from an "afterload mismatch" of the LA booster pump function.

METHODS

We investigated the effect of dobutamine infusion (3 microg/kg/min) on the LA pump function in the presence of elevated LV filling pressure induced by aortic constriction (Aoc) during acute MI in 10 dogs. Transmitral flow velocity was determined by transesophageal echocardiography, LV pressure by a micromanometer and LV volume by a conductance catheter. We measured the early (E) and late (A) diastolic peak transmitral flow velocities (cm/s) and LV chamber stiffness (deltaP/deltaV: mm Hg/ml; where deltaP is developed pressure and deltaV is the absolute filling volume during LA contraction).

RESULTS

When the deltaP/deltaV was increased by Aoc during MI (from 1.1 +/- 0.8 to 3.1 +/- 2.6 mm Hg/ml, p < 0.01), A decreased significantly (from 30 +/- 5 to 22 +/- 8 cm/s, p < 0.01), and the ratio of E to A increased (from 1.0 +/- 0.3 to 1.4 +/- 0.8, p < 0.05) compared with MI without Aoc, showing the pseudonormal transmitral flow pattern, the so called "LA afterload mismatch." Dobutamine under this condition significantly reduced the deltaP/deltaV (to 1.7 +/- 1.2 mm Hg/ml, p < 0.05), resulting in an increase in A (to 31 +/- 8 cm/s, p < 0.01) and a decrease in E/A (to 1.0 +/- 0.3, p < 0.05), and the transmitral flow became a prolonged relaxation pattern as in MI without Aoc in all dogs. There was an inverse correlation between the deltaP/deltaV and the time-velocity integral of A (r = -0.70, p < 0.01).

CONCLUSIONS

Dobutamine improved the afterload mismatch of the LA booster pump function. This effect may have been due to the reduction in LV operational chamber stiffness, resulting in an increase in the LA forward ejection into the LV.

Antagonist of pituitary adenylate cyclase activating polypeptide suppresses prolactin secretion without changing the activity of dopamine neurons in lactating rats

Pituitary adenylate cyclase activating polypeptide (PACAP) is a relatively new neuropeptide, and it has a potent stimulatory effect on adenylate cyclase activity in rat pituitary cells. However, the role of PACAP in the physiological control of prolactin (PRL) secretion is still unclear. In the present study, we investigated the physiological significance of endogenous PACAP on PRL secretion in lactating rats. On lactation days 7-8, pups were separated from their mother rats for 5 h before the onset of suckling and PACAP6-38 (16 microg), a receptor antagonist, was injected through the lateral ventricle cannula just after the removal of pups. The effects of PACAP6-38 on PRL and oxytocin secretion, and on the activity of tyrosine hydroxylase (TH), were examined after the onset of suckling. Administration of PACAP6-38 inhibited PRL levels in response to suckling, but it did not affect the activity of TH, as measured by DOPA accumulation at 15 min after administration of NSD 1015 (25.0 mg/kg), an L-aromatic amino acid decarboxylase inhibitor, or the plasma concentrations of oxytocin in lactating rats. Injection of alpha-methyl-p-tyrosine (alpha-MT; 50 mg/kg), an inhibitor of dopamine synthesis, increased PRL levels, and suckling caused a further increase in the plasma concentrations of PRL. An injection of PACAP6-38 (i.c.v.) also inhibited the PRL response to suckling under dopamine depletion. These results suggest that endogenous PACAP acts as a neurotransmitter or neuromodulator within the hypothalamus and plays an important role for PRL secretion in lactating rats. Endogenous PACAP may regulate PRL secretion, possibly mediated by PRL-releasing factors such as vasoactive intestinal polypeptide or vasopressin.

Large amounts of apicoplast nucleoid DNA and its segregation in Toxoplasma gondii

Apicoplasts (apicomplexan plastids) are nonphotosynthetic, secondary endosymbiotic plastids that are found in most apicomplexans. Although these organelles are essential for parasite survival, their functions, activities, and structures are not well understood. We examined the apicoplast nucleoid of Toxoplasma gondii from a morphological aspect by high-resolution epifluorescence microscopy and electron microscopy. We found unexpectedly large amounts of DNA in the nucleoid and the presence of several division-related structures. Initially, we identified the organellar nucleoids by staining with the DNA-specific dye 4',6-diamidino-2-phenylindole. A single nucleoid was observed per apicoplast, and the fluorescent spot representing the nucleoid was bright and spherical in contrast to the weak and filamentous spot representing the mitochondrial nucleoid. We also measured the DNA content of each apicoplast nucleoid by a video-intensified microscope photon-counting system and determined that the genomic copy number was at least 25, a figure over four times greater than that reported previously. Moreover, several groups of apicoplasts had significantly higher genomic copy numbers. The DNA molecules were accurately divided into two daughter apicoplasts just before nuclear division. In addition, we examined nucleoid segregation and the division apparatus using electron microscopy. However, we failed to observe nucleoid structures, suggesting that the apicoplasts are predominantly composed of nucleoid material. In addition, we observed "cap" structures at the termini of dividing apicoplasts, a possible plastid-dividing ring, and a microbody-like granule around the constriction. These structures may be involved in apicoplast division.

Gene disruption analysis of DppA isolated as a periplasmic molecular chaperone-like protein for folding of dimethyl sulfoxide reductase in Rhodobacter sphaeroides f. sp. denitrificans

The effect of inactivation of DppA, a dipeptide transport protein identified as a periplasmic molecular chaperone-like protein, on the formation of active dimethyl sulfoxide reductase (DMSOR) was examined in Rhodobacter sphaeroides f. sp. denitrificans. All of the dppA-disrupted mutants produced a normal level of native form of DMSOR and grew by DMSO respiration, indicating that the loss of DppA protein alone had no effect on the formation of active DMSOR. The periplasmic fraction of the dppA-disrupted mutant also had the activity to prevent aggregation of acid-unfolded DMSOR. Two proteins, DctP and BztA, were further identified as the proteins with the activity. Their activities, however, were much lower than that of DppA. These results suggest that several substrate binding proteins might be implicated in the folding of unfolded DMSOR in the periplasm.

Infective endocarditis with extensive calcified granulation of the mitral annulus and valve--a case report

Mitral annular calcification, a degenerative process usually seen in the elderly or in chronic renal failure, is rarely seen in an extensive form. A 69-year-old man with no history of renal failure, rheumatic fever, or heart disease had mitral valve vegetation and regurgitation, together with extensive mitral annuls and valve calcification, which may or may not have been secondary to the infective endocarditis.

Vasodilator responses of coronary conduit and resistance arteries to continuous nitroglycerin infusion in humans: a Doppler guide wire study

To examine the responses of coronary conduit and resistance arteries to the continuous i.v. administration of nitroglycerin in 15 patients with atypical chest pain, we measured coronary blood flow velocity in the left anterior descending coronary artery using a Doppler guide wire and the lumen diameter and cross-sectional area by quantitative coronary angiography. Systolic flow, diastolic flow, total coronary flow, and coronary vascular resistance were calculated. Stepwise increases in dose of nitroglycerin resulted in significant dose-dependent decrease in mean aortic pressure (p < 0.01) and increase in lumen diameter (p < 0.05). After nitroglycerin administration of 0.5 microg/kg/min, systolic flow decreased significantly by 89.9+/-15.7% (p < 0.01), and diastolic flow increased significantly by 74.2+/-37.1% (p < 0.05). Total coronary flow did not change significantly with the various doses of nitroglycerin. However, coronary vascular resistance decreased significantly at concentrations greater than 0.5 microg/kg/min nitroglycerin. Continuous nitroglycerin infusion did not reduce either diastolic or total coronary blood flow despite a significant reduction in coronary perfusion pressure. These results indicate that subendocardial blood flow might be maintained during continuous i.v. infusion of nitroglycerin within the clinical dose range.