A case of acute and late coronary events after blunt chest trauma: Attention to the late onset angina.

Mechanisms of acute myocardial infarction caused by traumatic coronary artery injury have been reported. However, late-onset coronary artery stenosis associated with trauma is less well known. We experienced a case in which acute myocardial infarction of the right coronary artery occurred at the time of blunt chest trauma (BCT) caused by a traffic accident and an increase in coronary artery stenosis in the left anterior descending artery (LAD) branch about 1 year later. A comparison of a volume-rendering image created from enhanced-contrast computed tomography at the time of trauma and coronary angiography revealed that the trauma site and the stenotic lesion in the LAD were in very close proximity, suggesting to us that traumatic coronary artery injury without flow limitation may have developed into high-grade stenosis in the LAD 1 year later. In this case we were able to demonstrate a causal relationship between BCT and delayed coronary artery stenosis. After BCT, it is necessary to be aware of the possibility of delayed coronary artery stenosis even if coronary injury is absent in the acute phase. .

In Paroxysmal Atrial Fibrillation Patients, the Neutrophil-to-lymphocyte Ratio Is Related to Thrombogenesis and More Closely Associated with Left Atrial Appendage Contraction than with the Left Atrial Body Function.

Objective The neutrophil-to-lymphocyte ratio (NLR) is an inflammation marker that can be used to detect atrial inflammatory changes, which may contribute to a reduced left atrial (LA) function and thrombosis. Our study aimed to determine whether or not the association of NLR with the LA appendage (LAA) function in relation to thrombogenesis differs from the association with the LA body function in paroxysmal atrial fibrillation (PAF) patients. Methods A total of 183 PAF patients were studied. The LA volume index, mitral flow velocity (A), and mitral annular motion velocity (A') were examined using transthoracic echocardiography. The LAA area, LAA wall motion velocity, and presence of spontaneous echo contrast (SEC) were examined using transesophageal echocardiography. Results The NLR of patients with cerebral embolism was significantly greater than in patients without the disorder. A cut-off point of 2.5 for the NLR had a sensitivity of 71% and a specificity of 74% in predicting cerebral embolism. The patients with an NLR ≥2.5 had a higher CHADS2 score and greater LA volume index or LAA area than those with an NLR <2.5. The NLR was an independent risk factor for SEC and was significantly correlated with the LAA wall motion velocity (r=-0.409) in 153 patients without SEC and with the LAA wall motion velocity and LAA area (r=-0.583, r=0.654, respectively) in 30 patients with SEC, but not with the LA volume index, A, or A' in either group. Conclusion In PAF patients, a high NLR indicates thrombogenesis with a high degree of certainty and is associated with reduced LAA contraction rather than with the LA body function.

Relevance of transthoracic left atrial appendage wall velocity measurement in addition to left atrial volume for noninvasive and quantitative assessment of left atrial thrombogenesis in patients with atrial fibrillation and normal D-dimer levels.

PURPOSE: This study examined the role of left atrial (LA) appendage wall velocity (LAAWV) measurement in addition to LA size for the noninvasive assessment of thrombogenesis in patients with atrial fibrillation (AF) and normal plasma D-dimer levels. METHODS: In 58 non-valvular AF patients, LAAWV and the LA volume index (LAVI) were determined by transthoracic echocardiography. LA appendage flow velocity and severity of spontaneous echo contrast (SEC) were determined by transesophageal echocardiography. RESULTS: LAAWV was strongly correlated with LA appendage flow velocity (r = 0.82), and LAVI was weakly correlated with LA appendage flow velocity (r = -0.37). As SEC severity increased, LAAWV decreased (p < 0.001) and LAVI increased (p < 0.001). Among 52 patients with normal D-dimer levels, LAAWV < 10 cm/s had 71 % sensitivity and 94 % specificity for diagnosing severe SEC. Severe SEC was not found in 18/32 large LAVI patients (>34 mL/m(2)), but 17 of the 18 patients (94 %) had LAAWV < 10 cm/s. Severe SEC was found in 3/20 patients with normal LAVI, but all of them showed LAAWV < 10 cm/s. CONCLUSION: The noninvasive measurement of transthoracic LAAWV in addition to LA volume is clinically relevant for quantitatively assessing thrombogenesis in AF patients with normal D-dimer levels.

Clinical outcomes and causes of death in Japanese patients with long-term inferior vena cava filter implants and deep vein thrombosis.

BACKGROUND AND PURPOSE: We assessed the causes of death and efficacy of permanent inferior vena cava (IVC) filters for preventing new pulmonary embolisms (PE) in Japanese deep vein thrombosis (DVT) patients with or without PE. METHODS AND SUBJECTS: We studied the clinical outcomes during the follow-up period of 1 day to 9 years (median: 18 months; mean: 28 months) in 66 of 72 consecutive patients (44 with acute PE, 27 with intrapelvic DVT, and 1 with floating femoral vein thrombosis). Fifty of 66 patients received anticoagulant therapy after the filter placement. RESULTS: Five patients died within 1 month (median 9 days) after the filter placement: three from recurrence of PE, one from cancer, and one from sepsis. Two of the three patients with recurrence of PE had preexisting intracardiac thrombi in the right atrium or main pulmonary artery before filter implantation. Ten patients died from the underlying disease (cancer: 7; brain hemorrhage: 1; amyotrophic lateral sclerosis: 1; pneumonia: 1) over 1 month after the filter placement (median follow-up period: 21 months). No new symptomatic PE recurrence was observed over 1 month after the filter placement. The 61 patients with long-term follow-up had no deterioration of DVT, and all the 31 patients who underwent multi-slice computed tomography showed no PE recurrence or filter thrombus occlusion, fracture, or migration. CONCLUSIONS: Underlying diseases and preexisting intracardiac thrombi may be the determining factors for the prognosis of DVT patients. Permanent IVC filters with anticoagulant therapy may be effective for preventing death from new PE in Japanese DVT patients.

High plasma human atrial natriuretic peptide and reduced transthoracic left atrial appendage wall-motion velocity are noninvasive surrogate markers for assessing thrombogenesis in patients with paroxysmal atrial fibrillation.

BACKGROUND: The clinical relevance of examining human atrial natriuretic peptide (HANP) or left atrial appendage (LAA) wall-motion velocity during sinus rhythm in paroxysmal atrial fibrillation (AF) patients has not been clearly elucidated. METHODS: The subjects were 38 patients with paroxysmal AF who underwent transesophageal and transthoracic echocardiography during sinus rhythm. The presence of spontaneous echocontrast (SEC) was examined with transesophageal echocardiography and LAA wall-motion velocity (LAAWV) was measured with transthoracic tissue Doppler echocardiography. Plasma HANP was measured within 3 hours after echocardiography. RESULTS: Human atrial natriuretic peptide ranged from 12 to 106 pg/mL with an average of 43 ± 24 pg/mL and had a significant correlation with LAAWV (r = -0.57) or LAA flow velocity (r = -0.41). HANP was significantly higher in patients with SEC than in patients without SEC (64 ± 29 vs. 34 ± 15 pg/mL, P = 0.008) and LAAWV was significantly lower in patients with SEC than in patients without SEC (13 ± 5 vs. 20 ± 5 cm/sec, P = 0.002). HANP >44 pg/mL had a sensitivity of 73% and specificity of 89% for diagnosing SEC. SEC was more frequently observed (73%) in patients with HANP >44 pg/mL and/or LAAWV <10 cm/sec as compared with patients (11%) with normal HANP and LAA wall-motion velocity (P < 0.0001). CONCLUSION: Higher plasma HANP and lower LAA wall-motion velocity may be noninvasive surrogate markers for assessing left atrial thrombogenesis during sinus rhythm in paroxysmal AF patients.

Efficacy of pulmonary vein isolation on left atrial function in paroxysmal and persistent atrial fibrillation and the dependency on its baseline function.

BACKGROUND: The effects of pulmonary vein (PV) isolation in atrial fibrillation (AF) on left atrial (LA) function or PV flow have not been well documented. METHODS: We examined the LA function and PV flow before and 3-6 months after PV isolation in 67 AF patients (34 paroxysmal [PAF] and 33 persistent [CAF]) using transesophageal echocardiography. RESULTS: AF recurred in 6/34 patients with PAF and in 6/33 patients with CAF 6 months after PV isolation. A larger LA dimension, a lower systolic PV flow velocity, and a lower ratio of systolic to diastolic PV flow velocity were related to a higher incidence of AF recurrence. The increment of left atrial appendage (LAA) flow velocity (55% vs. 22%) and systolic PV flow velocity (57% vs. 20%) after PV isolation tended to be greater in CAF than in PAF. The changes in LAA flow velocity had reverse correlations with the baseline values before PV isolation (PAF: r = -0.73, CAF: r = -0.58). The changes in mitral flow velocity during atrial contraction in PAF had reverse correlations with the baseline values before PV isolation (r = -0.84). The changes in systolic and diastolic PV flow velocity of PAF had reverse correlations with the baseline values before PV isolation (r = -0.56, r = -0.66). CONCLUSION: The baseline LA function may affect AF recurrence as well as the improvement of LA function, and the benefit of successful PV isolation might be greater in CAF than in PAF.

An extremely large coronary aneurysm associated with a quadricuspid aortic valve in an adult patient.

A 68-year-old woman exhibited an increasingly protruding mass on the left heart border on chest X-ray. Transthoracic echocardiography revealed an echo-free mass in the anterior pericardial space. Transesophageal echocardiography revealed blood flow from the proximal left anterior descending coronary into a large coronary artery aneurysm measuring 61 mm × 51 mm in diameter and a quadricuspid aortic valve with a small cusp between the left and right coronary cusps. Coronary angiography demonstrated the presence of a coronary aneurysm connected to the proximal left coronary anterior descending artery. A giant coronary artery aneurysm and pulmonary artery fistulas extending from the left and right coronary arteries were confirmed by surgeons and successfully treated with surgery.

Role of transthoracic left atrial appendage wall motion velocity in patients with persistent atrial fibrillation and a low CHADS2 score.

BACKGROUND AND PURPOSE: Thromboembolic risk has been examined by semi-invasive transesophageal echocardiography. We assessed the risk of thrombogenesis in patients with persistent atrial fibrillation (AF) noninvasively by using transthoracic tissue Doppler echocardiography (TDE) in relation to a low CHADS2 score. METHODS: Eighty patients with persistent AF underwent both transthoracic and transesophageal echocardiography. Peak left atrial appendage (LAA), wall motion velocity (WV) during LAA contraction was measured by transthoracic and transesophageal TDE. LAA flow velocity was also determined by transesophageal echocardiography. RESULTS: Transthoracic LAAWV could be measured in 78 of the 80 patients, and the values were closely correlated with transesophageal TDE values (r=0.98) and with transesophageal LAA flow velocity (r=0.82). Transthoracic LAAWV was significantly lower with increasing spontaneous echo contrast (SEC) severity (severe SEC, mild SEC, no SEC: 5.7±2.4, 10.2±3.3, and 14.5±5.5cm/s, respectively). Severe SEC was noted in 31 of 61 patients with a CHADS2 score ≤2, in 19 of 46 patients with a CHADS2 score ≤1 and in 6 of 21 patients with a CHADS2 score=0. For diagnosing severe SEC, a transthoracic LAAWV <10cm/s had a sensitivity of 81% and specificity of 92% in the patients with a CHADS2 score ≤2, a sensitivity of 74% and specificity of 91% in the patients with a CHADS2 score ≤1 and a sensitivity of 44% and specificity of 83% in the patients with a CHADS2 score=0. CONCLUSIONS: A transthoracic LAAWV <10cm/s in persistent AF patients with a low CHADS2 score may be a very specific diagnostic tool for evaluating severe SEC, one of the high risk factors for thromboembolism.

Better stent expansion by two-time inflation of stent balloon and its responsible mechanism.

OBJECTIVES: We determined the effect of two-time inflation of the stent balloon on stent expansion and its responsible factor. METHODS: Subjects included 61 patients with de novo coronary artery lesions, in whom 12 sirolimus-eluting, 27 paclitaxel-eluting, and 22 other stents were deployed twice at identical inflation pressures (11.3±2.3 atm) and inflation times (5, 10, 20, and 40 s). After the first and second deployments, minimum lumen diameter (MLD), minimum lumen area (MLA), and distensibility index (DI) were determined using intravascular ultrasound. RESULTS: After the second inflation, MLA was significantly increased (5 s: 12.9%, 10 s: 14.5%, 20 s: 9.4%, 40 s: 9.5%). MLD and DI were also significantly increased. In the single and double inflation groups, DI in each group was significantly correlated with inflation time (single: r=0.409, double: r=0.351). DI was not significantly different between double 5-s and single 10-s inflations, between double 10-s and single 20-s inflations, or between double 20-s and single 40-s inflations. Additional stent balloon inflation by higher pressure in 30% and another balloon in 18% of the patients were required. CONCLUSIONS: Two-time stent balloon inflation may allow better stent expansion regardless of inflation time and two-time inflation may be equivalent to longer inflation.

Differences of BiAtrial Substrate Properties in Patients with Different Types of AF.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in clinical practice and induces cardiac dysfunction and strokes. The development of AF requires a"trigger" and also an electroanatomic "substrate" capable of both initiating and perpetuating AF. Over the past decade, the understanding of the AF substrate properties in both atria has increased with fractionation and frequency analyses of the local atrial electrograms using three-dimensional electroanatomic mapping systems. The purpose of this review was to discuss the differences in the atrial substrate properties in patients with different types of AF.

The origin and clinical significance of the signal opposite to the mitral E-wave: a simple and novel indicator of left ventricular filling pressure.

OBJECTIVES: We noted a low-velocity signal opposite to the early diastolic transmitral flow (E) by pulsed Doppler echocardiography. The purpose of this study was to examine the origin and significance of this signal. BACKGROUND: The background of the signal remains uncertain. METHODS: We studied 59 adult patients (34 men and 25 women; mean age, 58.9 [20.2] years) without mitral valve heart disease. Mitral E-wave velocity and the signal (EW) opposite the E-wave were measured by pulsed Doppler echocardiography. Early diastolic mitral valve ring motion velocity (Ea) was measured by pulsed tissue Doppler echocardiography. Pulmonary capillary wedge pressure (PCWP) was measured by a Swan-Ganz catheter in 34 of the 59 patients. RESULTS: A blue signal was observed during early diastole from the mitral valve ring to the mitral orifice areas by color tissue Doppler echocardiography. The velocity profile method revealed the same direction and time between peak Ea and EW. Peak EW positively correlated with Ea (r = 0.67, P < 0.01). There were significant positive correlations between mean PCWP and E/Ea (r = 0.61, P < 0.01) and E/EW (r = 0.59, P < 0.01). E/EW was significantly greater in patients with PCWP > 12 mmHg than in patients with PCWP ≤ 12 mmHg (5.6 [1.3] cm/s vs. 4.3 [0.9] cm/s, P < 0.01). CONCLUSIONS: EW may be related to mitral valve ring motion, and the E/EW ratio may be a noninvasive simple parameter for assessing left ventricular filling pressure.

Transthoracic tissue Doppler assessment of left atrial appendage contraction and relaxation: their changes with aging.

AIM: We assessed left atrial appendage (LAA) function using transthoracic tissue Doppler echocardiography (TDE), and examined the influence of aging on LAA contraction and relaxation. METHODS: The subjects were 45 consecutive patients with heart disease and 110 healthy individuals. LAA wall motion velocity (LAAWV) at the tip of the LAA was measured using transthoracic echocardiography (TTE) and/or transesophageal echocardiography (TEE). RESULTS: We successfully recorded and measured LAAWV using TTE in 105 (95%) of the 110 healthy subjects. When angle correction was applied for the Doppler beam in TTE, LAAWV during contraction (LAAWVc) measured by TTE closely correlated with that measured by TEE (r = 0.97), and LAAWV during relaxation (LAAWVr) measured by TTE closely correlated with that measured by TEE (r = 0.95). LAAWVc and LAAWVr measured by TTE correlated significantly with the LAA flow velocities during LAA contraction and LAA relaxation measured by TEE (r = 0.64, P < 0.001; r = 0.53, P = 0.001). In healthy subjects, although LAAWVc remained unchanged with aging, LAAWVr significantly declined with aging (r =-0.48, P < 0.001) and had a significant negative correlation with left atrial dimension and a significant positive correlation with transmitral flow and annulus velocity during early diastole. CONCLUSION: Transthoracic TDE can provide information on LAA function. LAA relaxation may be impaired with aging and may be accompanied by early diastolic left ventricular dysfunction and chronic overload to the left atrium.

The responsibility of left atrial size and wall contraction velocity to left atrial active emptying in relation to the mitral flow velocity pattern.

The aim of this study was to investigate the role and limitations of left atrial (LA) preload or contractility as determinants of active LA emptying in patients with heart failure. In 56 healthy individuals (controls) and 30 patients with heart failure, the LA volume before atrial contraction (LAV(pre) I), the LA volume reduction (LASVI) and LA wall contraction velocity (LAWV) during atrial contraction, and the transmitral peak flow velocities during early diastole (E) and atrial contraction (A) were determined using two-dimensional pulsed Doppler or tissue Doppler echocardiography. LAV(pre) I and LASVI were positively correlated in patients whose A/E ratio was ≥1 (r = 0.58) and negatively correlated in those whose A/E ratio was <1 (r =-0.63). LAWV was significantly lower in those with heart failure than in the controls 2.2 (1.2) cm/sec, versus 3.3 (0.8) cm/sec; mean (standard deviation) and negatively correlated with left ventricular end-diastolic pressure (r =-0.37). LAWV and LASVI were significantly correlated (r = 0.71). This correlation was stronger in the patients whose A/E ratio was <1 than in those whose A/E ratio was ≥1. Multivariate regression analysis showed that LAWV was the only factor affecting LASVI. In patients with heart failure and an A/E ratio of <1, the contribution of LA dilatation to active LA emptying may be limited, and LAWV may be the most important determinant of active LA emptying, even if this velocity is decreased because of elevated left ventricular diastolic pressure.

Determinants of enhanced left atrial active emptying with aging: left atrial preload, contractility or both?

OBJECTIVE: Senile persons have reduced left ventricular (LV) relaxation and increased late diastolic filling. However, the determinant factor of the enhanced active emptying of the left atrium has not been well established. METHODS: Subjects were 62 healthy individuals with a mean age of 58+/-19 (21-85) years. The biplane modified Simpson's rule was applied to measure left atrial (LA) volume at pre-atrial contraction (LAVpre) as an index of LA preload and LA volume change during atrial contraction (LASV) as an index of active LA emptying. These values were divided by the body surface area and represented as LAVpreI and LASVI, respectively. Postero-basal (dorsal cranial) left atrial wall velocity (LAWV) during atrial contraction as an index of LA contractility was measured in the apical three-chamber view by two-dimensional tissue Doppler echocardiography. RESULTS: Age significantly correlated with mitral flow velocity (TMA), velocity-time integral during atrial contraction (TMAVTI) and LASVI (r= 0.63, p<0.001 and r=0.71, p<0.001, r=0.21, p=0.049, respectively). LAVpreI was significantly correlated with age (r=0.44, p<0.001), LASVI (r=0.71, p<0.001), TMA (r=0.31, p=0.008) and TMAVTI (r=0.40, p<0.001). LAWV remained unchanged with aging and had no correlation with TMA, TMAVTI or LASVI. CONCLUSION: The enlargement of the LA in senile persons may be a major determinant of enhanced active LA emptying and the increased LA contractility may be less contributory.

Validation of transthoracic tissue Doppler assessment of left atrial appendage function.

This study aimed to validate left atrial (LA) wall contraction velocity during atrial contraction (LAWV) in assessing LA function in 22 patients with paroxysmal atrial fibrillation. LAWV at the posterobasal LA wall was measured by transthoracic tissue Doppler echocardiography. LAWV was lower in patients with paroxysmal atrial fibrillation than in control subjects. It was more correlated with LA appendage velocity (r = 0.81) and fractional shortening (r = 0.85) than with parameters related to mitral inflow velocity or ring motion. With a LAWV cut-off value of 1.0 cm/s, receiver operator characteristic analysis curve showed a diagnostic sensitivity of 92% and a specificity of 80% in the identification of patients with spontaneous echocontrast. Among 8 patients with LAWV < or = 1.0 cm/s, cerebral embolism was evident in 3 and LA thrombus in 2, whereas the patients with LAWV greater than 1.0 cm/s had neither. LAWV may be useful to evaluate LA function and risk of embolism.

Successful coil embolization with assistance of coronary stenting in an adult patient with a huge coronary arterial-right atrial fistula.

A 55 year-old man with huge coronary artery fistula to the right atrium is presented. The Qp/Qs ratio was 1.6. We failed to place simultaneously three interlocking detachable coils for closing the fistula, because the coils were washed out into the right atrium. We deployed the coronary stent at the distal portion of the coronary artery. This procedure enabled us to anchor 7 electrically or interlocking detachable coils and to interrupt the shunt flow. A Doppler flow wire was useful to reveal instantaneously the extent of flow reduction even when contrast angiography was not performed in each procedure.

Left atrial appendage function in patients with systemic embolism in spite of in sinus rhythm.

OBJECTIVE: We sought to investigate whether left atrial (LA) appendage (LAA) function was impaired in patients with systemic embolism in sinus rhythm. METHODS: Transesophageal echocardiography was performed in 7 patients within 5 days after embolism (early group) and in 32 patients, more than 5 days after embolism (late group). We searched intracardiac thrombus and determined LAA area and LAA flow velocity, and the grade of spontaneous echocontrast. RESULTS: LA thrombus could be detected in 2 of the 39 patients only in early group (P = .028). The patients of early group, as compared with late group, had lower LAA flow velocity (28 +/- 16 vs 60 +/- 26 cm/s, P = .007) and higher grade of spontaneous echocontrast score (1.14 +/- 1.46 vs 0.25 +/- 0.62, P = .013). LA dimension and LAA area were not statistically different. CONCLUSION: LAA function may be impaired early after embolism even in sinus rhythm.

Four days of percutaneous cardiopulmonary support and sixteen days of percutaneous left atrium-artery bypass: a case report of survival of acute myocardial infarction with cardiogenic shock and severe rhabdomyolysis [corrected].

A severe acute myocardial infarction patient with cardiogenic shock was successfully treated with percutaneous coronary intervention, percutaneous cardiopulmonary support (PCPS), and percutaneous left atrium-artery bypass (LAAB). LAAB assisted the patient's circulation sufficiently, with few complications. The patient recovered from shock after LAAB. High fever and elevation of CPK disappeared after removal of the intra-aortic balloon pump (IABP). Staphylococcus epidermidis was detected in the culture of the IABP tip later. A small left atrium-right atrium shunt remained for ten months after LAAB removal and disappeared naturally. The patient was discharged 7 months after his initial myocardial infarction. He has been well for over one year since discharge without the need for re-hospitalization [corrected]

Left atrial wall motion velocity measured by the velocity profile method with tissue Doppler echocardiography in normal subjects: its relation to aging.

PURPOSE: The aim of this study was to find a method for measuring left atrial wall velocity (LAWV) during atrial contraction using tissue Doppler echocardiography. METHODS: The velocity profile method was used to measure left atrial wall velocity at several sites in 64 healthy individuals aged 25-84 years. We attempted to find maximum left atrial wall velocity (LAWVmax) by mapping on four-chamber, two-chamber, short-axis, and long-axis views and studied the relations between maximum left atrial wall velocity, age, and peak velocity during atrial contraction in mitral or pulmonary venous flow. RESULTS: Left atrial wall velocity was varied by changing the position of the sampling volume. The velocity profile pattern was similar to the left ventricular wall velocity pattern near the mitral valve annulus in the left atrium. Left atrial wall velocity had a positive peak during atrial contraction when the sample volume was located in the cranial and dorsal area. Maximum left atrial wall velocity was obtained in 74% of cases with the two-chamber view. Maximum left atrial wall velocity in healthy subjects was 3.1 ± 0.7 cm/s, and the duration of the atrial contraction was 112 ± 12 ms. Maximum left atrial wall velocity increased slightly with age but was not significantly correlated with peak velocity during atrial contraction in mitral or pulmonary venous flow. CONCLUSIONS: Left atrial wall velocity was measured by the velocity profile method in 64 healthy subjects aged 25-84 years. Maximum left atrial wall velocity increased slightly with age but was not significantly correlated with the peak velocity during atrial contraction in mitral or pulmonary venous flow.

Altered interaction of HDAC5 with GATA-1 during MEL cell differentiation.

The transcription factor GATA-1 plays a significant role in erythroid differentiation and association with CBP stimulates its activity by acetylation. It is possible that histone deacetylases (HDACs) repress the activity of GATA-1. In the present study, we investigated whether class I and class II HDACs interact with GATA-1 to regulate its function and indeed, GATA-1 is directly associated with HDAC3, HDAC4 and HDAC5. The expression profiling and our previous observation that GATA-2 interacts with members of the HDAC family prompted us to investigate further the biological relevance of the interaction between GATA-1 and HDAC5. Coexpression of HDAC5 suppressed the transcriptional potential of GATA-1. Our results demonstrated that GATA-1 and HDAC5 colocalized to the nucleus of murine erythroleukemia (MEL) cells. Furthermore, a portion of HDAC5 moved to the cytoplasm concomitant with MEL cell erythroid differentiation, which was induced by treatment with N,N'-hexamethylenebisacetamide. These observations support the suggestion that control of the HDAC5 nucleocytoplasmic distribution might be associated with MEL cell differentiation, possibly through regulated GATA-1 transactivation.