Comparison between febuxostat and allopurinol uric acid-lowering therapy in patients with chronic heart failure and hyperuricemia: a multicenter randomized controlled trial

Objective

Heart failure (HF) is a common and highly morbid cardiovascular disorder. Oxidative stress worsens HF, and uric acid (UA) is a useful oxidative stress marker. The novel anti-hyperuricemic drug febuxostat is a potent non-purine selective xanthine oxidase inhibitor. The present study examined the UA-lowering and prognostic effects of febuxostat in patients with HF compared with conventional allopurinol.

Methods

This multicenter, randomized trial included 263 patients with chronic HF who were randomly assigned to two groups and received allopurinol or febuxostat (UA >7.0 mg/dL). All patients were followed up for 3 years after enrollment.

Results

There were no significant differences in baseline clinical characteristics between the two groups. The UA level was significantly decreased after 3 years of drug administration compared with the baseline in both groups. Urine levels of the oxidative stress marker 8-hydroxy-2′-deoxyguanosine were lower in the febuxostat group than in the allopurinol group (11.0 ± 9.6 vs. 22.9 ± 15.9 ng/mL), and the rate of patients free from hospitalization due to worsening HF tended to be higher in the febuxostat group than in the allopurinol group (89.0% vs. 83.0%).

Conclusions

Febuxostat is potentially more effective than allopurinol for treating patients with chronic HF and hyperuricemia.

This study was registered in the University Hospital Medical Information Network Clinical Trials Registry (https://www.umin.ac.jp/ctr/; ID: 000009817).

Difference of clinical course after catheter ablation of atrioventricular nodal reentrant tachycardia between younger and older patients: atrial vulnerability predicts new onset of atrial fibrillation

BACKGROUND

The aim of this study was to compare the long-term procedural outcomes, the stability of atrioventricular conduction, and the new onset of atrial fibrillation (AF), after ablation of atrioventricular nodal reentrant tachycardia (AVNRT).

METHODS AND RESULTS

Consecutive patients with AVNRT (n=109), who underwent slow-pathway ablation, were divided into two groups based on the median age of the studied patients: the younger group aged <55 years and the older group aged ≥55 years. During a mean follow-up period of 60.6 months, the rate of change in the PR interval from before ablation to follow-up was significantly greater in older patients compared with younger patients. However, there was no delayed-onset high-degree AV block during follow-up in either group. No patients in the younger group suffered from persistent AF, whereas persistent AF occurred in 5/54 (9.3%) older patients. Multivariate Cox analysis revealed that atrial vulnerability, with induction of AF during the electrophysiological study, was the only predictor of the development of AF (Hazard ratio: 13.9, 95% confidence interval: 1.62-119.2, p<0.01).

CONCLUSION

Slow-pathway ablation of AVNRT is a reliable strategy even in older patients. However, physicians should consider regular long-term follow-up of older patients with atrial vulnerability, in order to assess the subsequent development of AF.

Serum carboxy-terminal telopeptide of type I collagen (ICTP) predicts cardiac events in chronic heart failure patients with preserved left ventricular systolic function

BACKGROUND

Clinical markers to predict adverse outcome have not yet been established for patients with preserved left ventricular (LV) systolic function. The present study was designed to examine whether carboxy-terminal telopeptide of type I collagen (ICTP), a marker of collagen degradation, is useful for determining the prognosis of such patients.

METHODS AND RESULTS

Serum levels of ICTP were measured at admission in 156 consecutive patients hospitalized for chronic heart failure (CHF). Patients were divided into 2 groups based on the LV ejection fraction (LVEF): reduced LV systolic function group (LVEF <50%, n=92) and preserved LV systolic function group (LVEF > or =50%, n=64). In preserved LV systolic function group, cardiac event-free rates were significantly lower in high ICTP group than in low ICTP group (p<0.001). The area under the receiver operating characteristic curve of ICTP in the preserved LV systolic function group was markedly larger than that in the reduced LV systolic function group. Cox multivariate analysis also revealed that ICTP was an independent predictor of cardiac events in the preserved LV systolic function group.

CONCLUSION

Serum ICTP level is highly reliable for risk stratifying CHF patients with preserved LV systolic function.

High serum level of pentosidine, an advanced glycation end product (AGE), is a risk factor of patients with heart failure

BACKGROUND

Pentosidine, one of the advanced glycation end products (AGE), is generated by nonenzymatic glycation and oxidation of proteins. The receptor of AGE (RAGE) is expressed in a variety of tissue, and interaction of AGE with RAGE induces oxidative stress and activation of intracellular signaling, causing production of cytokines and mediators of inflammation. We investigated whether serum pentosidine is a risk factor for heart failure.

METHODS AND RESULTS

Serum pentosidine concentration was measured in 141 patients with heart failure and 18 control subjects by a competitive enzyme-linked immunosorbent assay. Patients were prospectively followed during a median follow-up period of 479 days with end points of cardiac death or rehospitalization. Serum concentration of pentosidine was significantly higher in New York Heart Association (NYHA) Class III/IV patients than in NYHA class I/II patients (P < .0001). Serum pentosidine was also higher in patients with cardiac events than in event-free patients (P < .001). In the univariate Cox proportional hazard analysis, age, NYHA class, pentosidine, creatinine, uric acid, B-type natriuretic peptide, left ventricular end-systolic volume, and left ventricular mass were significant risk factors to predict cardiac events. In the multivariate Cox analysis, serum pentosidine concentration was an independent risk factor for cardiac events (hazard ratio 1.88, 95% confidence interval 1.23-2.69, P = .002). The highest 4th quartile of pentosidine was associated with the highest risk of cardiac events (4.52-fold).

CONCLUSIONS

Serum pentosidine concentration is an independent prognostic factor for heart failure, and this new marker may be useful for risk stratification of patients with heart failure. Patients were divided into 4 groups based on the serum pentosidine levels.

Heart-type fatty acid-binding protein is more sensitive than troponin T to detect the ongoing myocardial damage in chronic heart failure patients

BACKGROUND

Heart-type fatty acid-binding protein (H-FABP) is a small cytosolic protein and released into the circulation when the myocardium is injured. Previous studies have demonstrated that both H-FABP and troponin T (TnT) are detectable in venous blood samples in chronic heart failure (CHF) patients, suggesting the presence of ongoing myocardial damage (OMD). We hypothesized that a cytosolic marker (H-FABP) is more sensitive than a myofibrillar component (TnT) in the detection of OMD in CHF.

METHODS AND RESULTS

We measured serum H-FABP and TnT levels in 126 consecutive CHF patients at admission, and patients were followed-up with a mean period of 474 +/- 328 days. Cutoff values for H-FABP (4.3 ng/mL) and TnT (0.01 ng/mL) were determined from previous studies. Positive rate of H-FABP was higher than that of TnT in all CHF patients (46% [58/126] versus 26% [33/126], P < .0001), and in severe CHF (New York Heart Association III/IV) patients (69% [34/49] versus 47% [23/49], P = .0121). There were 27 cardiac events during a follow-up period. In patients with cardiac events, H-FABP was more frequently detected than TnT (88% [24/27] versus 44% [12/27], P = .0103). There were 33 patients with positive H-FABP among 93 patients with negative TnT. Those patients had more severe New York Heart Association class, higher levels of brain natriuretic peptide, and higher rates of cardiac events (36% versus 5%, P < .0001) compared with those both H-FABP and TnT were negative. Kaplan-Meier analysis demonstrated that in patients with negative TnT, positive H-FABP group had higher risk for cardiac events than negative H-FABP group (P < .0001). A multivariate analysis with Cox proportional hazard model showed that H-FABP was the only independent predictor of cardiac events (hazard ratio 15.677, P = .0001). The area under the receiver operating characteristic curve was larger for H-FABP than for TnT (0.779 versus 0.581; P = .009), suggesting that H-FABP had greater predictive capacity for cardiac events than TnT.

CONCLUSIONS

H-FABP was more sensitive to detect OMD and could identify patients at high risk more effectively than TnT.

Cardiac sympathetic denervation and ongoing myocardial damage for prognosis in early stages of heart failure

BACKGROUND

Iodine-123-metaiodobenzylguanidine ((123)I-MIBG) can assess cardiac sympathetic nervous function. Heart-type fatty acid binding protein (H-FABP) has been used as a marker of ongoing myocardial damage. The prognostic value of combination (123)I-MIBG imaging and H-FABP in heart failure is unknown.

METHODS AND RESULTS

We prospectively enrolled consecutive 104 patients with heart failure in whom we quantified (123)I-MIBG scintigraphy, simultaneously measured serum H-FABP and plasma brain natriuretic peptide (BNP) levels, and analyzed clinical outcomes. The multivariate Cox regression analysis revealed that augmented H-FABP level and decreased heart to mediastinum ratio of (123)I-MIBG at 240 minutes (delayed H/M ratio), but not BNP, were the independent predictors for cardiac events. The cutoff values for H-FABP and delayed H/M ratio were determined from the receiver operating characteristic curves as 5.2 ng/mL for H-FABP and 1.73 for delayed H/M ratio. The cardiac event rate was markedly higher in patients with both H-FABP and delayed H/M ratio of (123)I-MIBG was abnormal. Conversely, no cardiac events occurred in patients with both H-FABP level and delayed H/M ratio were normal.

CONCLUSION

H-FABP adds independent prognostic information to delayed H/M ratio of (123)I-MIBG imaging, and the combination of these approaches may improve the accuracy of prognostic determination in heart failure.

Serum Resistin is Associated With High Risk in Patients With Congestive Heart Failure A Novel Link Between Metabolic Signals and Heart Failure

BACKGROUND

Resistin is derived from fat tissue in rodents, and serum levels are elevated in animal models of obesity and insulin resistance. Recent studies have reported that resistin is correlated with markers of inflammation and oxidative stress and is predictive of coronary atherosclerosis in humans. However, clinical significance of serum resistin has not been examined in heart failure. Therefore, the purpose of this study was to examine whether: (1) resistin is correlated with the severity of heart failure; and (2) resistin can predict clinical outcomes of patients with heart failure.

METHODS AND RESULTS

Serum levels of resistin in 126 patients hospitalized for heart failure and 18 control subjects were measured. The patients were followed up with end-points of cardiac death and re-hospitalization caused by worsening of heart failure. The serum resistin level was higher in patients with heart failure than in control subjects and increased with advancing New York Heart Association functional class. The normal upper limit of the resistin level was determined as the mean +2 standard deviation value of control subjects (14.1 ng/ml). In heart failure patients, the cardiac event rate was higher in patients with a high resistin level than in those with a normal level. Among age, body mass index, serum levels of resistin, brain natriuretic peptide, loop diuretics selected by the univariate Cox regression hazard analysis, age and resistin were significant predictors of future cardiac events by multivariate Cox analysis.

CONCLUSION

Serum resistin was related to the severity of heart failure and associated with a high risk for adverse cardiac events in patients with heart failure.

Cystatin C, a novel measure of renal function, is an independent predictor of cardiac events in patients with heart failure

BACKGROUND

Cystatin C, a novel endogenous marker of glomerular filtration rate, has been reported as more sensitive to detect renal insufficiency than creatinine. The purpose of the present study was to examine the clinical significance of serum cystatin C level in patients with mild to moderate heart failure.

METHODS AND RESULTS

Serum levels of cystatin C were measured by an enzyme immunoassay in 140 patients with heart failure and 64 control subjects without heart failure. Patients were prospectively followed during a median follow-up period of 480 days, with the end points of cardiac death and progressive heart failure requiring rehospitalization. Serum levels of cystatin C were higher in patients with heart failure than in control subjects (1.14 +/- 0.60 ng/mL versus 0.72 +/- 0.14 ng/mL, P < .001). The Cox multivariate proportional hazard analysis revealed that a change of 1 standard deviation (SD) in cystatin C level was the one of independent predictor for cardiac events (hazard ratio, 1.94; 95% confidence interval, 1.29-6.64; P < .01). The cardiac event rate was markedly higher in patients with elevated cystatin C level (> or =1.0 ng/mL) than in those with normal level (< or =1.0 ng/mL) (38.7% versus 10.3%, P < 0.001). Furthermore in patients with normal creatinine levels (n = 91), the cardiac event rate was similarly higher in patients with elevated cystatin C than in those with normal levels (29.2% versus 7.5%, P = .002).

CONCLUSION

Elevation of serum cystatin C, a new marker of renal function, provides promising prognostic information for clinical outcome in patients with mild to moderate heart failure.

Central role of endogenous Toll-like receptor-2 activation in regulating inflammation, reactive oxygen species production, and subsequent neointimal formation after vascular injury

BACKGROUND

It is now evident that inflammation after vascular injury has significant impact on the restenosis after revascularization procedures such as angioplasty, stenting, and bypass grafting. However, the mechanisms that regulate inflammation and repair after vascular injury are incompletely understood. Here, we report that vascular injury-mediated cytokine expression, reactive oxygen species (ROS) production, as well as subsequent neointimal formation requires Toll-like receptor-2 (TLR-2) mediated signaling pathway in vivo.

METHODS AND RESULTS

Vascular injury was induced by cuff-placement around the femoral artery in non-transgenic littermates (NLC) and TLR-2 knockout (TLR-2KO) mice. After cuff-placement in NLC mice, expression of TLR-2 was significantly increased in both smooth muscle medial layer and adventitia. Interestingly, we found that inflammatory genes expression such as tumor necrosis factor-alpha, interleukin-1beta (IL-1beta), IL-6, and monocyte chemoattractant protein-1 were markedly decreased in TLR-2KO mice compared with NLC mice. In addition, ROS production after vascular injury was attenuated in TLR-2KO mice compared with NLC mice. Since we observed the significant role of endogenous TLR-2 activation in regulating inflammatory responses and ROS production after vascular injury, we determined whether inhibition of endogenous TLR-2 activation can inhibit neointimal proliferation after vascular injury. Neointimal hyperplasia was markedly suppressed in TLR-2KO mice compared with WT mice at both 2 and 4 weeks after vascular injury.

CONCLUSIONS

These findings suggested that endogenous TLR-2 activation might play a central role in the regulation of vascular inflammation as well as subsequent neointimal formation in injured vessels.

Hyperuricemia associated with high cardiac event rates in the elderly with chronic heart failure

OBJECTIVES

Congestive heart failure (CHF) is the major cause of death and hospitalization in the elderly population. Simple markers that can be measured anywhere at low cost are necessary to identify patients at high risk. Recent studies have reported that hyperuricemia is a prognostic marker for CHF. However, it is not yet known whether serum levels of uric acid may provide prognostic information in the elderly population. Therefore, this study tried to identify the clinical characteristics of elderly CHF patients (+/-70 years) in our institution and to evaluate whether uric acid levels can effectively estimate the prognosis for elderly CHF patients.

METHODS AND RESULTS

Uric acid levels were analyzed in 247 CHF patients, and patients were followed up for 451 +/- 235 days (mean +/- SD). Elderly CHF patients aged > or =70 years (123 patients) had higher rate of hypertension, lower current smoking rate and higher uric acid levels than those aged < 70 years (124 patients). There were 72 cardiac events including cardiac deaths and readmissions for worsening CHF. Multivariate analysis with the Cox proportional hazard model showed that uric acid was the only independent predictor of cardiac events (hazard ratio 1.544, 95% confidence interval 1.215-2.582, p < 0.0001) in the elderly with CHF. The highest quartile of uric acid level was associated with the highest risk of cardiac events (a 4.45-fold compared to the lowest quartile). Kaplan-Meier analysis revealed that uric acid levels effectively risk stratified elderly CHF patients for cardiac events.

CONCLUSIONS

These findings suggest that measurement of uric acid levels in elderly CHF patients may add valuable prognostic information to predict cardiac events.

Ongoing myocardial damage relates to cardiac sympathetic nervous disintegrity in patients with heart failure

Iodine-123-metaiodobenzylguanidine (123I-MIBG) has been used to assess the integrity and function of the cardiac sympathetic nervous system in patients with heart failure. Heart-type fatty acid binding protein (H-FABP) is released into the circulation when the myocardium is injured, and H-FABP has been recently used as a novel marker for the diagnosis of ongoing myocardial damage.

OBJECTIVE

The aim of the present study was to compare cardiac sympathetic nervous activity assessed by 123I-MIBG imaging with serum levels of H-FABP in patients with heart failure.

METHODS

Fifty patients with chronic heart failure were studied. 123I-MIBG imaging was carried out at 30 min (early) and 240 min (delayed) after the tracer injection. We measured serum levels of H-FABP using a sandwich enzyme linked immunosorbent assay.

RESULTS

Heart to mediastinum (H/M) ratios of 123I-MIBG decreased and washout rate increased with higher New York Heart Association (NYHA) functional class. H-FABP, norepinephrine and brain natriuretic peptide (BNP) levels increased as the severity of NYHA class advanced. Delayed H/M ratio was significantly correlated with H-FABP (r = -0.296, p = 0.029) and BNP (r = -0.335, p = 0.0213). Myocardial washout rate of 123I-MIBG was also correlated with H-FABP (r = 0.469, p < 0.001), norepinephrine (r = 0.433, p = 0.005), and BNP (r = 0.465, p = 0.001).

CONCLUSIONS

These data suggest that cardiac sympathetic nervous activation was associated with ongoing cardiomyocyte damage characterized by an elevated serum level of H-FABP in patients with heart failure. 123I-MIBG imaging is an appropriate approach to evaluate non-invasively not only cardiac sympathetic nervous activity, but also latent ongoing myocardial damage in the failing heart.

Cardiac-Specific Overexpression of Diacylglycerol Kinase ζ Prevents Gq Protein-Coupled Receptor Agonist-Induced Cardiac Hypertrophy in Transgenic Mice

Background— Diacylglycerol is a lipid second messenger that accumulates in cardiomyocytes when stimulated by Gqα protein-coupled receptor (GPCR) agonists such as angiotensin II, phenylephrine, and others. Diacylglycerol functions as a potent activator of protein kinase C (PKC) and is catalyzed by diacylglycerol kinase (DGK) to form phosphatidic acid and inactivated. However, the functional roles of DGK have not been previously examined in the heart. We hypothesized that DGK might prevent GPCR agonist-induced activation of diacylglycerol downstream signaling cascades and subsequent cardiac hypertrophy.

Methods and Results— To test this hypothesis, we generated transgenic (DGKζ-TG) mice with cardiac-specific overexpression of DGKζ. There were no differences in heart size and heart weight between DGKζ-TG and wild-type littermate mice. The left ventricular function was normal in DGKζ-TG mice. Continuous administration of subpressor doses of angiotensin II and phenylephrine caused PKC translocation, gene induction of atrial natriuretic factor, and subsequent cardiac hypertrophy in WT mice. However, in DGKζ-TG mice, neither translocation of PKC nor upregulation of atrial natriuretic factor gene expression was observed after angiotensin II and phenylephrine infusion. Furthermore, in DGKζ-TG mice, angiotensin II and phenylephrine failed to increase cross-sectional cardiomyocyte areas and heart to body weight ratios. Phenylephrine-induced increases in myocardial diacylglycerol levels were completely blocked in DGKζ-TG mouse hearts, suggesting that DGKζ regulated PKC activity by controlling cellular diacylglycerol levels.

Conclusions— These results demonstrated the first evidence that DGKζ negatively regulated the hypertrophic signaling cascade and resultant cardiac hypertrophy in response to GPCR agonists without detectable adverse effects in in vivo hearts.

Serum heart-type fatty acid binding protein predicts cardiac events in elderly patients with chronic heart failure

BACKGROUND AND OBJECTIVES

Heart-type fatty acid binding protein (H-FABP) is released into the circulation from the damaged myocardium of patients with severe chronic heart failure. Chronic heart failure is the most frequent cause of death and disability in the elderly. However, there are no data for the prognostic value of H-FABP in the elderly population. This study investigated whether H-FABP can effectively predict the prognosis in elderly patients (> or = 70 years) with chronic heart failure.

METHODS

Serum H-FABP levels were measured in 90 chronic heart failure patients > or =70 years old (mean age 77 +/- 4 years, range 70-92 years), and patients were followed-up for 421 +/- 326 days.

RESULTS

There were 35 cardiac events (38.9%) including cardiac deaths and readmissions for worsening chronic heart failure. Multivariate analysis with the Cox proportional hazard model showed that H-FABP was the only independent predictor of cardiac events (chi2 = 6.640, p = 0.0100). Kaplan-Meier analysis revealed that H-FABP effectively risk stratified elderly patients with chronic heart failure for cardiac events.

CONCLUSIONS

These findings suggest that H-FABP is a reliable marker for prognosis in elderly patients with chronic heart failure.

Prognostic value of elevated circulating heart-type fatty acid binding protein in patients with congestive heart failure

BACKGROUND

Heart-type fatty acid binding protein (H-FABP) is released into the circulation when the myocardium is injured and is a novel marker for the diagnosis of acute myocardial infarction. The purpose of the present study was to examine the clinical significance of increased serum H-FABP levels in patients with congestive heart failure.

METHODS AND RESULTS

Serum levels of H-FABP were measured in 179 patients admitted with congestive heart failure and 20 age-matched normal controls by using a sandwich enzyme-linked immunosorbent assay. Patients were prospectively followed during a mean follow-up period of 20 months with the end points of cardiac death and progressive heart failure requiring rehospitalization. Serum levels of H-FABP were higher in patients with congestive heart failure than in control subjects (5.7 +/- 4.8 ng/mL versus 2.7 +/- 0.8 ng/mL, P < .01) and increased with advancing NYHA class (P < .01). The cardiac event rate was markedly higher in patients with elevated H-FABP levels than in those with normal levels (43% versus 7%, P < .0001). Furthermore, the Cox multivariate proportional hazard analysis revealed that the elevated H-FABP level was the only independent predictor for cardiac events (chi2= 7.397, P < .01).

CONCLUSIONS

Elevation of H-FABP indicates latent and ongoing cardiomyocyte damage and identifies patients at high risk for future cardiac events in congestive heart failure.

Adenovirus-Mediated Overexpression of Diacylglycerol Kinase-ζ Inhibits Endothelin-1–Induced Cardiomyocyte Hypertrophy

Background— Diacylglycerol (DAG) is a lipid second messenger that transiently accumulates in cells stimulated by endothelin-1 (ET-1) and other Gαq protein-coupled receptor agonists. Diacylglycerol kinase (DGK) is thought to be an enzyme that controls the cellular levels of DAG by converting it to phosphatidic acid; however, the functional role of DGK has not been examined in cardiomyocytes. Because DGK inactivates DAG, a strong activator of protein kinase C (PKC), we hypothesized that DGK inhibited ET-1–induced activation of a DAG-PKC signaling cascade and subsequent cardiomyocyte hypertrophy.

Methods and Results— Real-time reverse transcription-polymerase chain reaction demonstrated a significant increase of DGK-ζ mRNA by ET-1 in cardiomyocytes. To determine the functional role of DGK-ζ, we overexpressed DGK-ζ in cardiomyocytes using a recombinant adenovirus encoding rat DGK-ζ (Ad-DGKζ). ET-1–induced translocation of PKC-ε was blocked by Ad-DGKζ ( P <0.01). Ad-DGKζ also inhibited ET-1–induced activation of extracellular signal-regulated kinase ( P <0.01). Luciferase reporter assay revealed that ET-1–mediated increase of activator protein-1 (AP1) DNA-binding activity was significantly inhibited by DGK-ζ ( P <0.01). In cardiomyocytes transfected with DGK-ζ, ET-1 failed to cause gene induction of atrial natriuretic factor, increases in [ 3 H]-leucine uptake, and increases in cardiomyocyte surface area.

Conclusions— We demonstrated for the first time that DGK-ζ blocked ET-1–induced activation of the PKC-ε–ERK-AP1 signaling pathway, atrial natriuretic factor gene induction, and resultant cardiomyocyte hypertrophy. DGK-ζ might act as a negative regulator of hypertrophic program in response to ET-1, possibly by controlling cellular DAG levels.

Combination of Heart-Type Fatty Acid Binding Protein and Brain Natriuretic Peptide Can Reliably Risk Stratify Patients Hospitalized for Chronic Heart Failure

BACKGROUND

The aim of the present study was to prospectively study whether a combination of markers for myocardial cell injury and left ventricular overload at admission can reliably risk stratify patients hospitalized for chronic heart failure (CHF).

METHODS AND RESULTS

Serum concentrations of heart-type fatty acid binding protein (H-FABP) and plasma concentrations of brain natriuretic peptide (BNP) were measured at admission in 186 consecutive patients hospitalized for CHF. During a mean follow-up period of 534+/-350 days, there were 44 cardiac events, including 16 cardiac deaths and 28 readmissions for worsening heart failure. Normal upper limits for H-FABP and BNP values were determined from the receiver operating characteristic curves (4.3 ng/ml for H-FABP and 200 pg/ml for BNP). A stepwise Cox regression analysis demonstrated that high H-FABP (hazard ratio 5.416, p = 0.0002) and high BNP (hazard ratio 2.411, p = 0.0463) were independent predictors of cardiac events. High concentrations of both H-FABP and BNP at admission were associated with the highest incidence of cardiac mortality and cardiac events. Kaplan-Meier analysis also showed that the combination of H-FABP and BNP concentrations could reliably stratify patients for cardiac events.

CONCLUSION

Combined measurement of H-FABP and BNP concentrations at admission may be a highly reliable evaluation for risk stratifying patients hospitalized for CHF.

Modulation of Doxorubicin-Induced Cardiac Dysfunction in Toll-Like Receptor-2–Knockout Mice

Background— Toll-like receptors (TLRs) are members of the interleukin-1 receptor family and are involved in the responsiveness to pathogen-associated molecular patterns. Recent studies have demonstrated that TLRs are activated by endogenous signals, such as heat shock proteins and oxidative stress, which may contribute to congestive heart failure. Oxidative stress is one of the major factors in doxorubicin (Dox)-induced cardiac dysfunction. Thus, we hypothesized that TLRs contribute to the pathogenesis of Dox-induced cardiac dysfunction.

Methods and Results— Cardiac dysfunction was induced by a single injection of Dox (20 mg/kg IP) into wild-type (WT) mice and TLR-2–knockout (KO) mice. Five days after Dox injection, left ventricular dimension at end-diastole was smaller and fractional shortening was higher in KO mice compared with WT mice ( P <0.01). Nuclear factor-κB activation and production of proinflammatory cytokines after Dox were suppressed in KO mice compared with WT mice ( P <0.01). The numbers of TUNEL-positive nuclei and Dox-induced caspase-3 activation were less in KO mice than in WT mice ( P <0.01). Survival rate was significantly higher in KO mice than in WT mice 10 days after Dox injection (46% vs 11%, P <0.05).

Conclusions— These findings suggest that TLR-2 may play a role in the regulation of inflammatory and apoptotic mediators in the heart after Dox administration.

Presence of intermittent J waves in multiple leads in relation to episode of atrial and ventricular fibrillation

Brugada syndrome is characterized by J wave and ST-segment elevation of right precordial leads and causes idiopathic ventricular fibrillation. We experienced a patient of Brugada syndrome with prominent J wave and ST-segment elevation not only in V(1) to V(3) but also in many leads. He suffered spontaneous ventricular fibrillation and resuscitated by direct current. He has no structural heart disease.

Dynamic 123I-BMIPP single-photon emission computed tomography in patients with congestive heart failure: effect of angiotensin II type-1 receptor blockade

BACKGROUND

Heart failure is a major and growing public health problem with a high mortality rate. Although recent studies have demonstrated that a variety of metabolic and/or neurohumoral factors are involved in the progression of this syndrome, the precise mechanisms responsible for this complex condition are poorly understood.

HYPOTHESIS

To examine 123I-beta-methyl-iodophenylpentadecanoic acid (BMIPP) kinetics in the early phase soon after tracer injection in patients with congestive heart failure (CHF), we performed dynamic single-photon emission computed tomography (SPECT).

METHODS

Twenty-six patients with CHF and eight control subjects were examined. The consecutive 15 images of 2-min dynamic SPECT were acquired for 30 min after injection. In the early phase after injection (0-4 min), a significant amount of radioactivity existed in the blood pool. After 6 min, the myocardial 123I-BMIPP image was clear and thus the washout rate of 123I-BMIPP from 6 to 30 min was calculated.

RESULTS

The washout rate of 123I-BMIPP from the myocardium was faster in patients with CHF than in the controls (8 +/- 4 vs. -5 +/- 3%, p < 0.01). The washout rate of 123I-BMIPP demonstrated positive correlation with left ventricular (LV) end-diastolic volume index (R = 0.54, p < 0.02) and inverse correlation with LV ejection fraction (R = 0.53, p <0.02). Patients were given the angiotensin II type-1 receptor antagonist candesartan for 6 months, and dynamic SPECT was repeated. The enhanced washout rate of 123I-BMIPP in CHF was reduced after treatment with candesartan (p < 0.05).

CONCLUSION

These data suggest that (1) enhanced washout of 123I-BMIPP was observed soon after injection in patients with CHF, (2) the activation of angiotensin II signaling pathway is involved as an intracellular mechanism for enhanced 123I-BMIPP washout in heart failure, and (3) improvement in fatty acid metabolism may represent a new mechanism for beneficial effects of angiotensin II receptor blockade on cardiac function and survival in patients with heart failure. 123I-BMIPP washout in the early phase obtained from dynamic SPECT may be a new marker for evaluating the severity of heart failure and the effects of medical treatment.

Dynamic123I-MIBG SPECT reflects sympathetic nervous integrity and predicts clinical outcome in patients with chronic heart failure

123I-metaiodobenzylguanidine (123I-MIBG) is useful for assessment of the severity and prognosis of patients with chronic heart failure (CHF). To examine 123I-MIBG kinetics in the early phase soon after tracer injection, we performed dynamic single photon emission computed tomography (SPECT) in 76 patients with CHF and 17 control subjects. The consecutive 15 images of 2 min-dynamic SPECT were acquired for 30 min after injection. From 0 to 4 min, a significant amount of radioactivity existed in the blood pool, thus we calculated washout rate of 123I-MIBG from 4 to 30 min (%WR-E). Patients were followed up with an end-point of cardiac death or re-hospitalization for 16 months (6-30 months). As the NYHA functional class advanced, %WR-E increased (control, NYHA class I, II, and III: 9 +/- 4%, 10 +/- 5%, 12 +/- 5%, and 17 +/- 5%*, respectively, *p < 0.01 vs. all other groups). Significant correlation was found between %WR-E and conventional WR from 30 min to 240 min (r = 0.606, p < 0.0001). %WR-E was positively correlated with left ventricular end-diastolic dimension (r = 0.372, p < 0.01) and was inversely correlated with left ventricular fractional shortening (r = -0.316, p < 0.02). The normal upper limit of %WR-E was defined as mean + 2SD value of 17 control subjects (17.1%). Patients with abnormally rapid %WR-E levels had a higher cardiac event rate than those with normal %WR-E levels (57% vs. 12%, p < 0.0001). These data suggest that washout rate of 123I-MIBG in the early phase from 4 min to 30 min (%WR-E) reflects cardiac sympathetic nervous integrity and is useful to evaluate the severity and prognosis of patients with CHF. The present results indicate a potential role of dynamic SPECT in shortening the 123I-MIBG imaging protocol.

Toll-like receptor-2 modulates ventricular remodeling after myocardial infarction

BACKGROUND

Toll-like receptors (TLRs) are members of the interleukin-1 receptor family and transduce similar signals as interleukin-1 receptor in response to exogenous pathogens. Recent studies have demonstrated that TLRs are activated by endogenous signals, such as heat shock proteins and oxidative stress, that may contribute to ventricular remodeling after myocardial infarction. In this study, we determined whether TLR-2 was involved in cardiac remodeling after myocardial infarction.

METHODS AND RESULTS

Myocardial infarction was induced by surgical left anterior descending coronary artery ligation on wild-type (WT) mice and TLR-2-knockout (KO) mice. The survival rate was significantly higher in KO mice than in WT mice 4 weeks after myocardial infarction (65% versus 43%, P<0.03). Infarct size and degree of inflammatory cell infiltration in infarct area were similar between WT and KO mice. However, myocardial fibrosis in the noninfarct area of KO mice was much less than in WT mice (P<0.01) and was accompanied by reduced transforming growth factor-beta1 and collagen type 1 mRNA expressions (P<0.01 and P<0.05, respectively). Left ventricular dimensions at end diastole were smaller in KO mice than in WT mice at 1 week (P<0.05) and 4 weeks (P<0.01) after surgery. Furthermore, fractional shortening was higher (27.7+/-2.5% versus 21.2+/-2.6%, P<0.05, at 1 week, and 24.3+/-2.0% versus 16.6+/-2.5%, P<0.01, at 4 weeks) in KO mice compared with WT mice.

CONCLUSIONS

These data suggest that TLR-2 plays an important role in ventricular remodeling after myocardial infarction.

Angiotensin-converting enzyme inhibition improves cardiac fatty acid metabolism in patients with congestive heart failure

This study aimed to examine whether angiotensin-converting enzyme (ACE) inhibition improved cardiac fatty acid metabolism in patients with congestive heart failure (CHF). Myocardial 123I-beta-methyl-iodophenylpentadecanoic acid (123I-BMIPP) imaging was performed in 25 patients with CHF and in 10 control subjects. Myocardial 123I-BMIPP images were obtained 30 min and 4 h after tracer injection. The heart-to-mediastinum (H/M) ratio of 123I-BMIPP uptake and the washout rate of 123I-BMIPP from the myocardium were calculated. Patients were given enalapril for 6 months, and 123I-BMIPP imaging was repeated. H/M ratios on early and delayed images were lower in CHF patients than in normal controls (P<0.01). The washout rate of 123I-BMIPP from the myocardium was faster in CHF patients than in controls (P<0.01). As the severity of the New York Heart Association (NYHA) functional class increased, the H/M ratio decreased and the washout rate increased. The washout rate of 123I-BMIPP was inversely correlated with left ventricular fractional shortening (R=-0.62, P<0.01). ACE inhibition with enalapril increased the H/M ratio on delayed images (P<0.05) and reduced the washout rate of 123I-BMIPP (P<0.05) in CHF patients. These data suggest that: (1) angiotensin II-mediated intracellular signalling activation may be a possible mechanism for the decreased myocardial uptake and enhanced washout of 123I-BMIPP in heart failure patients; and (2) the improvement in fatty acid metabolism by ACE inhibition may represent a new mechanism for the beneficial effect of this therapy in heart failure.

Dual response to Fas ligation in human endothelial cells: apoptosis and induction of chemokines, interleukin-8 and monocyte chemoattractant protein-1

BACKGROUND

To maintain the integrity of tissues, endothelial cells play critical roles. Fas ligand (FasL) is well known to deliver a death signal through its receptor, Fas. The Fas/FasL system may concomitantly induce expressions of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) besides triggering apoptosis in endothelial cells. We also investigated whether an inhibitor of caspase-8 (Z-IETD-FMK) does modulate IL-8 and MCP-1 secretion.

METHODS AND RESULTS

After treatment with interferon-gamma (IFN-gamma), human recombinant FasL (hr FasL) or Fas agonistic antibody (CH-11) was added to cultured human endothelial cells. IFN-gamma up-regulated Fas mRNA levels. Fas ligation promoted apoptosis assessed by fluorescent-activated cell sorter (FACS) analysis in a dose-dependent manner and induced prominent DNA fragmentation. Simultaneously, IL-8 and MCP-1 were secreted from the endothelial cells in response to hr FasL or CH-11 in a dose-dependent manner (P < 0.01). Fas-neutralizing agent (Fas-Fc) suppressed the Fas-mediated secretions of IL-8 and MCP-1 (P < 0.01) both as well as the Fas-mediated apoptosis. On the other hand, whereas Z-IETD-FMK suppressed apoptosis, the inhibitor enhanced the Fas-mediated secretions of both IL-8 and MCP-1 beyond the value of the Fas stimulation alone (P < 0.01), suggesting an enhanced signalling for the chemokine expression.

CONCLUSION

In human endothelial cells, the Fas/FasL system induces both IL-8 and MCP-1 secretions probably via a caspase-8 independent pathway. The Fas/FasL system may amplify the inflammatory cascade in the vascular injury and atherogenesis by recruiting leukocytes at the region of apoptotic endothelial damage.

Reactive oxygen species regulate FLICE inhibitory protein (FLIP) and susceptibility to Fas-mediated apoptosis in cardiac myocytes

OBJECTIVE

Fas ligand (FasL) is a key cytokine which initiates apoptosis when FasL binds to its receptor, Fas. Cardiac myocytes are generally resistant to Fas-induced apoptosis. However, sublethal dose of doxorubicin (Dox) can sensitize cardiac myocytes to Fas-induced apoptosis. We investigated the molecular mechanism by which Dox sensitizes cardiac myocytes to Fas-induced apoptosis. FLICE inhibitory protein (FLIP) is a key molecule for blocking Fas-induced apoptosis by functioning as a caspase-8 dominant negative.

METHODS AND RESULTS

FLIP was constitutively expressed in cultured neonatal rat cardiac myocytes. FLIP protein levels were markedly down-regulated by Dox in a time-dependent and dose-dependent manner. Next, we examined the relation of reactive oxygen species (ROS) by Dox to the expression of FLIP. Both of N-acetylcysteine (NAC) and the combination of superoxide dismutase and catalase restored the decreased FLIP in Dox-treated cardiac myocytes to the basal level. NAC also restored the increased formation of thiobarbituric acid-reactive substance after Dox-treatment. Concurrently, the susceptibility to Fas-mediated apoptosis disappeared with the treatments of the antioxidant agents. Hydrogen peroxide down-regulated FLIP in a dose-dependent fashion and also sensitized cardiac myocytes to Fas-induced apoptosis.

CONCLUSIONS

FLIP, an inhibitor of apoptosis induced by cytokines of TNF family, contributes at least partly to Dox-induced sensitization to Fas-mediated apoptosis in cardiac myocytes. The expression of FLIP in cardiac myocytes is regulated by ROS.

Pulsed Doppler tissue imaging for the assessment of myocardial viability: comparison with 99mTc sestamibi perfusion imaging

The aim of the present study was to examine whether Doppler tissue imaging demonstrated comparable diagnostic performance for the detection of viable myocardium compared to myocardial perfusion imaging with Tc hexakis-2-methoxyisobutylisonitrile (MIBI). We studied 30 patients with old myocardial infarction who underwent percutaneous transluminal coronary angioplasty (PTCA). Myocardial single photon emission computed tomography (SPECT) with Tc-MIBI and two-dimensional echocardiography were carried out within 7 days before PTCA. We measured regional Tc-MIBI uptake for each myocardial segment from SPECT and peak systolic velocity and a ratio of regional pre-ejection period to regional ejection time (PEP/ET) from pulsed Doppler tissue imaging. Biplane left ventriculography was performed before interventional procedures and repeated 3 months after PTCA. Myocardial viability was determined when wall motion was improved at least one grade after PTCA. The peak systolic velocity was positively correlated with regional Tc-MIBI uptake (R =0.59, P<0.01). The PEP/ET demonstrated inverse correlation with Tc-MIBI uptake ( R=-0.59, P<0.01). Peak systolic velocity of viable segments was higher than that of non-viable segments ( P<0.05). The PEP/ET was lower in viable segments than in non-viable segments ( P<0.05). Peak systolic velocity and PEP/ET demonstrated high diagnostic accuracy for detecting viable myocardium compared with Tc-MIBI perfusion imaging (80% and 79% vs 90%). These data indicate that measurements of regional peak systolic velocity and PEP/ET by Doppler tissue imaging are useful for evaluating myocardial viability quantitatively and provide helpful information for a clinical judgment in an interventional strategy.

CD14-deficient mice are protected against lipopolysaccharide-induced cardiac inflammation and left ventricular dysfunction

BACKGROUND

The molecular mechanisms responsible for sepsis-induced myocardial dysfunction remain undefined. CD14 mediates the inflammatory response to lipopolysaccharide (LPS) in various organs including the heart. In this study we investigated the role of CD14 in LPS-induced myocardial dysfunction in vivo.

METHODS AND RESULTS

Wild-type and CD14-deficient (CD14-D) mice were challenged with Escherichia coli LPS. Myocardial tumor necrosis factor, interleukin-1beta (IL-1beta), and NOS2 induction was measured before and 6 hours after LPS challenge. Echocardiographic parameters of left ventricular function were measured before and 6 hours after LPS administration. LPS challenge induced a significant increase in myocardial tumor necrosis factor and IL-1beta mRNA and protein expression in wild-type mice. In contrast, mRNA and protein levels for TNF and IL-1beta were significantly blunted in CD14-D mice. An increase in NOS2 protein was noted within 6 hours of LPS provocation only in the hearts of wild-type mice. This was associated with an increase in ventricular cGMP levels. Activation of nuclear factor-kappaB was observed within 30 minutes of LPS in the hearts of wild-type mice but not in CD14-D mice. In wild-type mice, LPS significantly decreased left ventricular fractional shortening, velocity of circumferential shortening, and dP/dt(max). LPS-treated CD14-D mice maintained normal cardiac function.

CONCLUSIONS

These results suggest that CD14 is important in mediating the proinflammatory response induced by LPS in the heart and that CD14 is necessary for the development of left ventricular dysfunction during LPS-induced shock in vivo.

Smoking behavior, initiating and cessation factors among Japanese nurses: a cohort study

The prevalence of smoking among Japanese nurses, specially in their twenties, is higher than that among the general female population. To examine smoking behavior, smoking initiating and cessation factors, we conducted a cohort study through questionnaire survey, targeting nurses (n=1572) working at 11 hospitals located in Tokyo metropolitan area. The first survey was conducted using a confidential questionnaire on smoking, followed by a second survey conducted in the same manner on the same subjects two years later. As to smoking status after two years, 8% (95%CI=1.5%) started smoking and 6% (95%CI=1.4%) quitted resulting in a 2% increase in the prevalence of current smoking. The average nicotine dependence for nurses who were smokers in the two surveys rose from 3.9 to 4.3 (P<0.05). Smoking behavior of mother, friends, or superiors at work had a significant influence on smoking behavior of nurses. As to smoking cessation factors, the idea that women and medical workers should not smoke, and living with family each had a significant influence. Considering the fact that 6% of nurses in this study succeeded in quitting smoking within two years, it is required that anti-smoking education be conducted at medical institutions to decrease the prevalence of current smoking among the nurses in Japan.

Expression of cementum-derived attachment protein in bovine tooth germ during cementogenesis

Cementum-derived attachment protein (CAP) is a 56 kDa collagenous protein that promotes attachment of mesenchymal cells. Previous studies have shown that the presence of CAP is restricted to cementum in adult human tissues. In this study, we report generation of a monoclonal antibody against CAP and its use for the investigation of CAP in developing bovine tooth germs. Mice were immunized with CAP purified from bovine cementum, and a monoclonal antibody, 3G9, was produced. Immunohistochemical staining of bovine tooth germ at root forming stage using 3G9 antibody showed that the tissue distribution of CAP expression was limited to cementum matrix and cementoblasts during cementogenesis. Alveolar bone did not stain with the 3G9 antibody, whereas anti-type I collagen stained positively. CAP was purified from bovine tooth germs with immunoaffinity purification using the 3G9 antibody. Examination of the immunoaffinity-purified fraction showed that CAP existed in tooth germ as a 65 kDa protein. The protein was susceptible to bacterial collagenase. To investigate the possible biological function of CAP during cementogenesis, we isolated dental follicle cells from the bovine tooth germ, and showed that they adhered to surfaces containing CAP. These data demonstrate that CAP is expressed by bovine cementoblasts as a 65 kDa protein and that the CAP may have a function in cementogenesis.

[The influence of lifestyle and night-shift work on sleep problems among female hospital nurses in Japan]

STUDY OBJECTIVE

In this study, by conducting a questionnaire survey, we aimed to clarify the situation regarding sleep disorders in female hospital nurses and their relation with night-shift work and lifestyle.

METHODS

The subjects were female nurses working at 5 hospitals, each with more than 400 beds. The survey was carried out in July 2000. The questionnaire contained six items concerning sleep quality from the Pittsburgh Sleep Quality Index (PSQI), two new items on sleep drafted by ourselves, and some questions on lifestyle and shift-work status.

RESULTS

Among all female nurses, statistically significant differences were observed between those working and those not working night shifts for 7 items regarding sleep (P < 0.05). Significant correlations were observed between sleep disorders and the following factors: (1) working night shift, (2) having anxiety or stress, (3) getting less than 6 hours of sleep, (4) working in cities, (5) having children, and (6) bathing more than 1 hour before going to bed. In addition, significant correlations were observed between getting less than 6 hours of sleep and the following factors: (1) being 40 years of age or older, (2) working in cities, and (3) having anxiety or stress.

CONCLUSIONS

The results of this study suggest that sleep problems among nurses are associated not only with night-shift work but also with lifestyle. They also suggest that nurses who work night shifts, especially in Tokyo, should try to get sufficient hours of sleep to ensure good quality of sleep.

Mitotic specific phosphorylation of serine-1212 in human DNA topoisomerase IIalpha

It is known that topoisomerase IIalpha is phosphorylated by several kinases. To elucidate the role of phosphorylation of topoisomerase IIalpha in the cell cycle, we have examined the cell cycle behavior of phosphorylated topoisomerase IIalpha in HeLa cells using antibodies against several phospho-oligopeptides of this enzyme. Here we demonstrate that serine1212 in topoisomerase IIalpha is phosphorylated only in the mitotic phase. Using an antibody against an oligopeptide containing phosphoserine-1212 in topoisomerase IIalpha (PS1212), subcellular localization of topoisomerase IIalpha phosphorylated at serine1212 was examined by indirect immunofluorescence staining, and compared with that of overall topoisomerase IIalpha. Serine1212-phosphorylated topoisomerase IIalpha was localized specifically on mitotic chromosomes, but not on interphase chromosomes; this result contrasts with overall topoisomerase IIalpha which was observed on chomosomes in both interphase and mitosis. Serine1212-phosphorylated topoisomerase lIalpha first appeared on chromosome arms in prophase, became concentrated on the centromeres in metaphase, and disappeared in early telophase. In addition, ICRF-193, a catalytic inhibitor of topoisomerase II, prevented accumulation of serine1212-phosphorylated topoisomerase IIalpha at the centromeres. These results indicate that serine1212 of topoisomerase IIalpha is phosphorylated specifically during mitosis, and suggest that the serine1212-phosphorylated topoisomerase IIalpha acts on resolving topological constraint progressively from the chromosome arm to the centromere during metaphase chromosome condensation.

[The validity of repeated mail surveys concerning smoking habits for Japanese physicians]

PURPOSE

A cross-sectional study of smoking prevalence among medical doctors was performed using questionnaires. Mailing four times proved essential in order to obtain a reasonable number of responses from the subjects. The objective of the present study was to analyze the smoking characteristics of the subjects who returned the questionnaires after the second to fourth mailings.

METHODS

A set of an anonymous questionnaire and a letter from the President of the Japan Medical Association (JMA) requesting cooperation was mailed with a return envelope with the subject's name and address written to 3,000 male and 1,500 female doctors randomly selected from the roster membership of the JMA. The survey was conducted between February and June 2000.

RESULTS

The collection rate after the first mailing was 66%, while the subtotal collection rate for the second through fourth mailings was 21%, bringing the grand-total to 87%. The total prevalence of smoking among the subjects who had sent back the questionnaire on the second to fourth mailings was approximately 1.5 times higher than for those who had sent back the questionnaire after the initial mailing for both male and female subjects. As to other characteristics of the subjects who only responded after the second to fourth mailings were: working in hospitals (odds ratios; male: 1.39, female: 1.47), not giving smoking cessation guidance (odds ratio; male: 0.58), and not recognizing the idea that doctors should not smoke (odds ratio; female: 0.67).

CONCLUSIONS

The results suggested that for future surveys on smoking to be conducted in academic institutions or work-places, efforts to obtain responses from those who do not answer the first attempt should take into consideration these points.

In vivo expression of proinflammatory mediators in the adult heart after endotoxin administration: the role of toll-like receptor-4

Tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and nitric oxide (NO) may play a role in lipopolysaccharide (LPS)-induced cardiac depression. Toll-like receptor-4 (TLR-4) mediates the cytokine response to LPS in immune cells. TLR-4 also is expressed in human and murine myocardial tissue. Therefore, the hypothesis that LPS induces proinflammatory cytokines in the heart via TLR-4 was tested. C3H/HeJ (TLR-4 deficient) and C3HeB/FeJ mice were studied. LPS induced a robust increase in myocardial TNF-alpha and IL-1beta mRNA in C3HeB/FeJ mice. The response in C3H/HeJ mice was blunted and delayed. Myocardial TNF-alpha and IL-1beta protein levels were higher in C3HeB/FeJ mice, as were inducible NO synthase protein and NO production. Activation of myocardial NF-kappaB was observed within 30 min in C3HeB/FeJ mice but not in C3H/HeJ mice. These findings suggest that myocardial TLR-4 is involved in signaling cytokine production within the heart during endotoxic shock.

Standard radial bone mineral density and physical factors in ordinary Japanese women

To prevent osteoporosis, which is expected to increase in incidence in this rapidly aging society, in recent years bone mineral density (BMD) has frequently been measured as a predisposition index. However, these measurements are made on different sites with different apparatus, and the results are independently studied by different institutions. In our present investigation, to establish the standard radius BMD as determined by dual-energy X-ray absorptiometry (DXA), we carried out a general population survey in 29 municipalities and prefectures on 11,252 locally residing females aged 15 to 83 years (mean, 35.61 +/- 12.85 years). Their YAM (young adult mean) BMD was estimated at 0.664 +/- 0.054 g/cm2, which was almost the same as the figure given in the 1996 version of the diagnostic criteria for primary osteoporosis. We further studied the relationships of BMD to age and physical factors known to be influential to BMD. It was found that BMD was correlated negatively to age and positively to body mass index (BMI). The average values we obtained for age and physique groups appeared to have provided reliable indices for the primary prevention of osteoporosis.

Enhanced expression and shedding of tumor necrosis factor (TNF) receptors from mononuclear leukocytes in human heart failure

TNFalpha exerts its functions by engaging two receptors (TNF-RI and TNF-RII). The extracellular parts of the receptors are proteolytically shed to the soluble forms by a matrix metalloproteinase-like enzyme (sTNF-RI and sTNF-RII). The soluble TNF receptors can neutralize TNFalpha activities. Circulating levels of both sTNF-RI and sTNF-RII are elevated in patients with congestive heart failure (CHF). It remains unclear how a large amount of sTNF-RI and sTNF-RII is mobilized into the circulation. Mononuclear leukocytes were obtained from 14 controls and 21 patients with CHF. TNF-RII of the cells from CHF patients was upregulated in the cell-surface expression and mRNA transcripts. Besides enhanced shedding of TNF-RII on the cells from CHF patients with phorbol myristate acetate (PMA), sera from CHF induced shedding of TNF-RII on the cells from normal volunteers. Thus, the enhancement of both expression and shedding of TNF-RII may be related to increased circulating levels of the soluble TNF receptor in patients with CHF. The presence of CHF may affect the regulation of TNF receptors, which may modulate the responsiveness to TNFalpha in the tissues of patients with CHF.

Cooperation between CD44 and LFA-1/CD11a adhesion receptors in lymphokine-activated killer cell cytotoxicity

IL-2-activated NK cells exhibit cytotoxic activity against a wide variety of tumor cells in a non-MHC-restricted fashion and in the absence of prior sensitization. The molecular mechanisms that regulate the cytotoxicity and attachment of activated killer cells to tumor target cells are not known. We provide genetic evidence in CD44(-/-) and LFA-1(-/-) mice that the cell adhesion receptors LFA-1 and CD44 regulate the cytotoxic activity of IL-2-activated NK cells against a variety of different tumor cells. This defect in cytotoxicity was significantly enhanced in mice that carried a double mutation of both CD44 and LFA-1. In vitro differentiation, TNF-alpha and IFN-gamma production, and expression of the cytolytic effector molecules perforin and Fas-L were comparable among IL-2-activated NK cells from LFA-1(-/-), CD44(-/-), CD44(-/-)LFA-1(-/-), and control mice. However, CD44(-/-), LFA-1(-/-), and CD44(-/-)LFA-1(-/-) IL-2-activated NK cells showed impaired binding and conjugate formation with target cells. We also show that hyaluronic acid is the principal ligand on tumor cells for CD44-mediated cytotoxicity of IL-2-activated NK cells. These results provide the first genetic evidence of the role of adhesion receptors in IL-2-activated NK killing. These data also indicate that distinct adhesion receptors cooperate to mediate binding between effector and target cells required for the initiation of "natural" cytotoxicity.

Soluble tumor necrosis factor receptors are elevated in relation to severity of congestive heart failure

The level of tumor necrosis factor alpha (TNF-alpha) is increased in patients with congestive heart failure and may play an important role in the development and progression of heart failure. Two types of TNF receptor (TNF-RI and TNF-RII) are expressed in virtually every cell and have different biologic roles. Soluble forms of the two receptors (sTNF-RI and sTNF-RII) have been identified as extracellular domain fragments. Serum levels of TNF-alpha, sTNF-RI and sTNF-RII were measured in 66 patients with heart failure and 27 control subjects using an enzyme-linked immunosorbent assay (ELISA). Hemodynamic variables, norepinephrine, atrial natriuretic peptide (ANP), and brain natriuretic peptide (BNP) were evaluated. TNF-alpha was significantly higher in patients with heart failure than in controls subjects (9.4 +/- 1.4 vs 4.8 +/- 0.8 pg/ml; p < 0.05). sTNF-RI and -RII were significantly increased in relation to the severity of heart failure (control subjects, 0.66 +/- 0.04 and 1.97 +/- 0.15 ng/ml; NYHA class II, 1.10 +/- 0.08 and 2.28 +/- 0.12 ng/ml; NYHA class III, 1.63 +/- 0.22 and 3.00 +/- 0.24 ng/ml; NYHA class IV, 2.78 +/- 0.46 and 4.52 +/- 0.62 ng/ml, respectively). In 9 patients whose clinical symptoms improved after treatment, the levels of sTNF-RI and -RII decreased by 17.3 +/- 5.7% (p < 0.05) and 22.1 +/- 6.9% (p < 0.05), respectively. There were significant positive correlations between sTNF-RI and -RII and mean pulmonary pressure (r = 0.69 and r = 0.61; p < 0.001) and mean capillary wedge pressure (r = 0.65 and r = 0.54; p < 0.001 and p < 0.01, respectively), but not with left ventricular end-diastolic volume or ejection fraction (NS). sTNF-RI and -RII were also significantly positively correlated with plasma levels of norepinephrine (r = 0.75 and r = 0.50; p < 0.001 and p < 0.05), ANP (r = 0.72 and r = 0.70; p < 0.001), and BNP (r = 0.60 and r = 0.60; p < 0.001). In conclusion, soluble TNF receptors are increased in proportion to the severity of congestive heart failure and may reflect the current status of congestive heart failure rather than the level of left ventricular dysfunction.

Serum levels of soluble form of Fas molecule in patients with congestive heart failure

Compared with soluble Fas molecule (sFas, an inhibitor of Fas-mediated apoptosis) in normal volunteers, the serum level of sFas significantly increased by 41% in New York Heart Association (NYHA) class III (p <0.05) and by 97% in NYHA class IV patients with congestive heart failure (p <0.001). Furthermore, sFas showed correlations with soluble forms of TNF receptor-p55 (RI) and -p75 (RII) (r = 0.68 and r = 0.56) which inhibit activities of TNF alpha.

Roles of nitric oxide and adenosine in the regulation of coronary conductance in the basal state and during reactive hyperemia

Nitric oxide (NO) and adenosine are important mediators in the regulation of coronary vascular tone and are released into the interstitium from the vascular endothelium and myocardium, respectively. The roles of these autacoids in the regulation of coronary flow in the basal and reactive hyperemic states were examined in Langendorff rabbit hearts perfused with oxygenated Krebs-Henseleit solution at 37 degrees C and 110 mmHg pressure. Instantaneous perfusion pressure-flow relationships were analyzed to derive coronary conductance both in the basal state and during the early phase of reperfusion (hyperemic state). N omega-nitro-L-arginine methyl ester (L-NAME) at increasing concentrations (10(-6) to 10(-4) mol/L) (n = 7) and 8-phenyltheophylline (8-PT) at increasing concentrations (10(-9) to 10(-6) mol/L) (n = 7) were applied to assess the role of NO and adenosine, respectively. L-NAME dose-dependently reduced the coronary conductance in both the basal and early hyperemic states, while 8-PT dose-dependently reduced conductance only in the hyperemic state. Changes in conductance during the early hyperemic phase correlated well with changes in the debt repayment ratio for either L-NAME (r = 0.94) or 8-PT (r = 0.99). These data suggest that a flow-related NO release mechanism regulates the coronary conductance in both the basal and hyperemic states while the metabolic regulation of adenosine release plays a role in the presence of ischemia.

Immunoaffinity purification and characterization of CACGTG sequence-binding proteins from cultured mammalian cells using an anti c-Myc monoclonal antibody recognizing the DNA-binding domain

c-Myc protein contains a basic helix-loop-helix and leucine zipper (bHLHLZ) structure in its carboxyl terminal region, forms heterodimers with Max, and binds to the CACGTG sequence in DNA. A number of bHLHLZ proteins are present in cells, and some of them bind to the same DNA sequence. Using an anti c-Myc monoclonal antibody, MYC5, raised against a bacterially synthesized c-Myc protein, we have carried out immunoaffinity purification of c-Myc proteins from cultured mammalian cells. The immunoaffinity-purified fraction was found to contain not only c-Myc but also other CACGTG sequence-binding proteins, such as Max, Mad, and USF, indicating a wide cross-reaction to CACGTG sequence-binding proteins. The MYC5 antibody recognized the common structural motif in their basic region required for sequence-specific DNA binding and was shown to inhibit their DNA-binding activities. The immunoaffinity-purified N-Myc, Max, Mad, and, presumably, c-Myc were highly phosphorylated, and phosphatase treatment increased the DNA-binding activity of Myc, suggesting that the DNA-binding activity of c-Myc was regulated by phosphorylation in vivo. From these results, we can conclude that the MYC5 antibody constitutes a powerful tool for the purification and characterization of c-Myc and other CACGTG sequence-binding proteins.

The distribution and expression of the two isoforms of DNA topoisomerase II in normal and neoplastic human tissues

In mammalian cells, there are two isoforms of DNA topoisomerase II, designated alpha (170-kDa form) and beta (180-kDa form). Previous studies using cell lines have shown that the topoisomerase IIalpha and beta isoforms are differentially regulated during the cell cycle and in response to changes in growth state. Moreover, both isoforms can act as targets for a range of anti-tumour drugs. Here, we have analysed the normal tissue distribution in humans of topoisomerase IIalpha and beta using isoform-specific antibodies. In addition, we have studied expression of these isoforms in 69 primary tumour biopsies, representative either of tumours that are responsive to topoisomerase II-targeting drugs (breast, lung, lymphoma and seminoma) or of those that show de novo drug resistance (colon). Topoisomerase IIalpha was expressed exclusively in the proliferating compartments of all normal tissues, and was detectable in both the cell nucleus and cytoplasm. In biologically aggressive or rapidly proliferating tumours (e.g. high-grade lymphomas and seminomas), there was a high level of topoisomerase IIalpha, although expression was still detectable in colon tumours, indicating that expression of this isoform is not sufficient to explain the intrinsic drug resistance of colon tumours. Topoisomerase IIbeta was expressed ubiquitously in vivo and was localized in both the nucleoli and the nucleoplasm. This isoform was present in quiescent cell populations, but was expressed at a generally higher level in all tumours and proliferating cells than in normal quiescent tissues. We conclude that topoisomerase IIalpha is a strict proliferation marker in normal and neoplastic cells in vivo, but that topoisomerase IIbeta has a much more general cell and tissue distribution than has topoisomerase IIalpha. The apparent up-regulation of topoisomerase IIbeta in neoplastic cells has implications for the response of patients to anti-tumour therapies that include topoisomerase II-targeting drugs.