[Association between atrial fibrillation reoccurrence and new-onset ischemic stroke among patients with nonvalvular atrial fibrillation]

Objective: Explore the association between atrial fibrillation (AF) reoccurrence and new-onset ischemic stroke (IS) in patients with nonvalvular AF, and explore whether there is a high-risk period of IS after recurrent episodes of AF. Methods: A nested case-control study design was used. A total of 565 nonvalvular AF patients with new-onset IS after a follow-up of at least 2 years in the China-AF cohort were enrolled as the case group, and 1 693 nonvalvular AF patients without new-onset IS were matched as the control group at a ratio of 1∶3. Frequency and types of recurrent AF in the previous 1 or 2 years were compared between two groups, and the adjusted associations of AF reoccurrence with new onset IS were explored using conditional logistic regression analysis. The proportion of recurrent AF was compared between the case period and control period, and conditional logistic regression analysis was performed to calculate adjusted associations of case-period AF with IS. Results: The nested case-control study design results showed that the proportion of at least one record of recurrent AF in the previous 1 year was higher in the case group than in the control group (72.0% vs. 60.8%, P<0.05), and the recurrent AF was positively correlated with new-onset IS (adjusted OR=1.80, P<0.001). Similar results were also observed in the previous 2 years period. The case-crossover study design analysis showed that among 565 patients with new-onset IS, recurrent AF in the case period was positively correlated with IS (adjusted OR=1.61, P=0.003). Conclusion: Recurrent AF is associated with IS, and there may be a high-risk period of IS after recurrent episodes of AF.

[Current use of oral anticoagulation therapy and influencing factors among coronary artery disease patients with nonvalvular atrial fibrillation in China]

Objective: To investigate current use of oral anticoagulant (OAC) therapy and influencing factors among coronary artery disease (CAD) patients with nonvalvular atrial fibrillation (NVAF) in China. Methods: Results of this study derived from "China Atrial Fibrillation Registry Study", the study prospectively enrolled atrial fibrillation (AF) patients from 31 hospitals, and patients with valvular AF or treated with catheter ablation were excluded. Baseline data such as age, sex and type of atrial fibrillation were collected, and drug history, history of concomitant diseases, laboratory results and echocardiography results were recorded. CHA₂DS₂-VASc score and HAS-BLED score were calculated. The patients were followed up at the 3rd and 6th months after enrollment and every 6 months thereafter. Patients were divided according to whether they had coronary artery disease and whether they took OAC. Results: 11 067 NVAF patients fulfilling guideline criteria for OAC treatment were included in this study, including 1 837 patients with CAD. 95.4% of NVAF patients with CAD had CHA₂DS₂-VASc score≥2, and 59.7% of patients had HAS-BLED≥3, which was significantly higher than NVAF patients without CAD (P<0.001). Only 34.6% of NVAF patients with CAD were treated with OAC at enrollment. The proportion of HAS-BLED≥3 in the OAC group was significantly lower than in the no-OAC group (36.7% vs. 71.8%, P<0.001). After adjustment with multivariable logistic regression analysis, thromboembolism(OR=2.48,95%CI 1.50-4.10,P<0.001), left atrial diameter≥40 mm(OR=1.89,95%CI 1.23-2.91,P=0.004), stain use (OR=1.83,95%CI 1.01-3.03, P=0.020) and β blocker use (OR=1.74,95%CI 1.13-2.68,P=0.012)were influence factors of OAC treatment. However, the influence factors of no-OAC use were female(OR=0.54,95%CI 0.34-0.86,P=0.001), HAS-BLED≥3 (OR=0.33,95%CI 0.19-0.57,P<0.001), and antiplatelet drug(OR=0.04,95%CI 0.03-0.07,P<0.001). Conclusion: The rate of OAC treatment in NVAF patients with CAD is still low and needs to be further improved. The training and assessment of medical personnel should be strengthened to improve the utilization rate of OAC in these patients.

[Efficacy and safety of radiofrequency catheter ablation of septal hypertrophy guided by intracardiac echocardiography in hypertrophic obstructive cardiomyopathy]

Nine patients identified as hypertrophic obstructive cardiomyopathy (HOCM) in Beijing Anzhen Hopspital who underwent ablation from March to July 2019 were included in the study. All patients had left ventricular outflow tract gradient (LVOTG) over 50 mmHg(1 mmHg=0.133 kPa)with significant symptoms despite not optimal drug therapy. Intracardiac echocardiography (ICE) was used to reconstruct septum and surrounding structures, and monitor the effect of ablation during procedure. Nine patients with HOCM were included,.of which 6 men and 3 women. The average age was (51.7±12.2) years. All patients underwent successful ablation after a mean of procedural time of (152.2±31.9) minutes and ablation time of (838.4±227.3) seconds. Except for one patients, all other patients had significant LVOTG reduction(P=0.001)within 50 mmHg after the procedure. Systolic anterior motion of the mitral valve disappeared in all patients after the procedure without major periprocedural complications. The LVOTG of these patients remained stable during follow-up. Radiofrequency ablation using ICE guidance is feasible in treating HOCM with promising efficacy and safety.

[A comparison of CAS risk model and CHA2DS2-VASc risk model in guiding anticoagulation treatment in Chinese patients with non-valvular atrial fibrillation]

Objective: To compare the differences between CAS risk model and CHA₂DS₂-VASc risk score in predicting all cause death, thromboembolic events, major bleeding events and composite endpoint in patients with nonvalvular atrial fibrillation. Methods: This is a retrospective cohort study. From the China Atrial Fibrillation Registry cohort study, the patients with atrial fibrillation who were>18 years old were randomly divided into CAS risk score group and CHA₂DS₂-VASc risk score group respectively. According to the anticoagulant status at baseline and follow-up, patients in the 2 groups who complied with the scoring specifications for anticoagulation were selected for inclusion in this study. Baseline information such as age and gender in the two groups were collected and compared. Follow-up was performed periodically to collect information on anticoagulant therapy and endpoints. The endpoints were all-cause death, thromboembolism events and major bleeding, the composite endpoint events were all-cause death and thromboembolism events. The incidence of endpoints in CAS group and CHA₂DS₂-VASc group was analyzed, and multivariate Cox proportional risk model was used to analyze whether the incidence of the endpoints was statistically different between the two groups. Results: A total of 5 206 patients with AF were enrolled, average aged (63.6±12.2) years, and 2092 (40.2%) women. There were 2 447 cases (47.0%) in CAS risk score group and 2 759 cases (53.0%) in CHA₂DS₂-VASc risk score group. In the clinical baseline data of the two groups, the proportion of left ventricular ejection fraction<55%, non-paroxysmal atrial fibrillation, oral warfarin and HAS BLED score in the CAS group were lower than those in the CHA₂DS₂-VASc group, while the proportion of previous diabetes history and history of antiplatelet drugs in the CAS group was higher than that in the CHA₂DS₂-VASc group, and there was no statistical difference in other baseline data. Patients were followed up for (82.8±40.8) months. In CAS risk score group, 225(9.2%) had all-cause death, 186 (7.6%) had thromboembolic events, 81(3.3%) had major bleeding, and 368 (15.0%) had composite endpoint. In CHA₂DS₂-VASc risk score group, 261(9.5%) had all-cause death 209(7.6%) had thromboembolic events, 112(4.1%) had major bleeding, and 424 (15.4%) had composite endpoint. There were no significant differences in the occurrence of all-cause death, thromboembolic events, major bleeding and composite endpoint between anticoagulation in CAS risk score group and anticoagulation in CHA₂DS₂-VASc risk score group (log-rank P =0.643, 0.904, 0.126, 0.599, respectively). Compared with CAS risk score, multivariable Cox proportional hazards regression models showed no significant differences for all-cause death, thromboembolic events, major bleeding and composite endpoint between the two groups with HR(95%CI) 0.95(0.80-1.14), 1.00(0.82-1.22), 0.83(0.62-1.10), 0.96(0.84-1.11), respectively. All P>0.05. Conclusions: There were no significant differences between CAS risk model and CHA₂DS₂-VASc risk score in predicting all-cause death, thromboembolic events, and major bleeding events in Chinese patients with non-valvular atrial fibrillation.

[The relationship between fasting blood glucose level and thromboembolism events in patients with non-valvular atrial fibrillation]

Objective: To explore the relationship between fasting blood glucose level and thromboembolism events in patients with non-valvular atrial fibrillation (NVAF). Methods: This was an observational study based on data from a multicenter, prospective Chinese atrial fibrillation registry cohort, which included 18 703 consecutive patients with atrial fibrillation (AF) in 31 hospitals in Beijing from August 2011 to December 2018. Patients were divided into 5 groups according to status of comorbid diabetes and fasting glucose levels at admission: normal blood glucose (normal glucose group), pre-diabetes group, strict glycemic control group, average glycemic control group and poor glycemic control group. Patients were followed up by telephone or outpatient service every 6 months. The primary follow-up endpoint was thromboembolic events, including ischemic stroke and systemic embolism. The secondary endpoint was the composite endpoint of cardiovascular death and thromboembolic events. Kaplan-Meier survival analysis and multifactorial Cox regression were used to analyze the correlation between fasting glucose levels and endpoint events. Results: The age of 18 703 patients with NVAF was (63.8±12.0) years, and there were 11 503 (61.5%) male patients. There were 11 877 patients (63.5%) in normal blood glucose group, 2 023 patients (10.8%)in pre-diabetes group, 1 131 patients (6.0%) in strict glycemic control group, 811 patients in average glycemic control group and 2 861 patients(4.3%) in poor glycemic control group. Of the 4 803 diabetic patients, 1 131 patients (23.5%) achieved strict glycemic control, of whom 328 (29.0%) were hypoglycemic (fasting blood glucose level<4.4 mmol/L at admission). During a mean follow-up of (51±23) months (up to 82 months), thromboembolic events were reported in 984 patients (5.3%). The survival curve analysis of Kaplan Meier showed that the incidence rates of thromboembolic events in normal glucose group, pre-diabetes group, strict glycemic control group, average glycemic control group and poor glycemic control group were 1.10/100, 1.41/100, 2.09/100, 1.46/100 and 1.71/100 person-years, respectively (χ²=53.0, log-rank P<0.001). The incidence rates of composite endpoint events were 1.86/100, 2.17/100, 4.08/100, 2.58/100, 3.16/100 person-years (χ²=72.3, log-rank P<0.001). The incidence of thromboembolic events and composite endpoint events in the other four groups were higher than that in the normal blood glucose group (P<0.001). Multivariate Cox regression analysis showed that compared with normal glucose group, the risk of thromboembolism increased in pre-diabetes group(HR=1.23, 95%CI 1.00-1.51, P=0.049), strict glycemic control group(HR=1.32, 95%CI 1.06-1.65, P=0.013) and poor glycemic control group(HR=1.26, 95%CI 1.01-1.58, P=0.044). Conclusion: Both high or low fasting glucose may be an independent risk factor for thromboembolic events in patients with NVAF.

[The impact of digoxin on the long-term outcomes in patients with coronary artery disease and atrial fibrillation]

Objective: To investigate the long-term safety of digoxin in patients with coronary artery disease (CAD) and atrial fibrillation (AF). Methods: This was a prospective study, in which 25 512 AF patients were enrolled from China Atrial Fibrillation Registry Study. After exclusion of patients receiving ablation therapy at the enrollment, 1 810 CAD patients [age: (71.5±9.3)years] with AF were included. The subjects were grouped into the digoxin group and non-digoxin group, and were followed up for a period of 80 months. Long-term outcomes were compared between the groups and an adjusted Cox regression analysis was applied to evaluate the risk of digoxin on the long-term outcomes. The primary endpoint was all-cause mortality. Results: The patients were followed up for a median period of 3.05 years. After multivariable adjustment, the Cox regression analysis showed that digoxin significantly increased the risk of all-cause mortality (HR=1.28, 95%CI 1.01-1.61, P=0.038), cardiovascular mortality (HR=1.48,95%CI 1.10-2.00,P=0.010), cardiovascular hospitalization (HR=1.67,95%CI 1.35-2.07,P=0.008) and the composite endpoints (HR=2.02,95%CI 1.71-2.38,P<0.001). In the subgroup of patients with heart failure (HF), digoxin was not associated with the risk of all-cause mortality, but was still associated with the increased risk of cardiovascular mortality (HR=1.44,95%CI 1.05-1.98,P=0.025), cardiovascular hospitalization (HR=1.44,95%CI 1.09-1.90,P=0.010) and the composite endpoints (HR=1.37, 95%CI 1.01-1.70, P=0.004). However, in the subgroup of patients without HF, digoxin was only associated with all-cause mortality (HR=2.56,95%CI 1.44-4.54,P=0.001). Conclusion: Digoxin significantly increased the risk of all-cause mortality in CAD patients with AF, especially in patients without HF.

[Causes of death and influencing factors of atrial fibrillation patients undergoing anticoagulation therapy]

Objective: To investigate the causes of death and predictors in patients with nonvalvular atrial fibrillation (AF) undergoing anticoagulation therapy. Methods: Consecutive anticoagulated nonvalvular AF patients were recruited from the China Atrial Fibrillation Registry (China-AF) Study from August 2011 to December 2018. After exclusion of patients with hypertrophic cardiomyopathy, dilated cardiomyopathy, or loss of follow-up within 1 year, 2 248 patients were included in this analysis. Enrolled patients were followed up were followed up for 3 and 6 months, and then every 6 months. The primary endpoint was death, including cardiovascular death, non-cardiovascular death and undetermined death. The patients were divided into survival group and death group according to the survival status after follow-up. Clinical information such as age and sex was collected. Cox proportional hazards regression was performed to identify associated risk factors for all-cause mortality, and Fine-Gray competing risk model was used to identify associated risk factors for cardiovascular mortality. Results: A total of 2 248 patients with atrial fibrillation receiving anticoagulant therapy died over a mean follow-up of (42±24) months, mean age was (67±10) years old and 41.1% (923/2 248) patients were female. The mortality rate was 2.8 deaths per 100 patient-years. The most common cause of death was cardiovascular deaths, accounted for 55.0% (120/218). Worsening heart failure was the most common cause of cardiovascular deaths (18.3% (40/218)), followed by bleeding events (12.9% (28/218)) and ischemic stroke (8.7% (19/218)). Multivariate Cox regression analysis showed that age (HR = 1.05, 95%CI 1.04-1.07, P<0.001), anemia (HR = 1.81, 95%CI 1.02-3.18, P = 0.041), heart failure (HR=2.40, 95%CI 1.75-3.30, P<0.001), ischemic stroke/transient ischemic attack (TIA)(HR = 1.59, 95%CI 1.21-2.13, P = 0.001) and myocardial infarction (HR = 2.93, 95%CI 1.79-4.81, P<0.001) were independently associated with all-cause death. Fine-Gray competing risk model showed that age (HR=1.05, 95%CI 1.02-1.08, P<0.001), heart failure (HR=2.81, 95%CI 1.79-4.39, P<0.001), ischemic stroke/TIA (HR=1.50, 95%CI 1.02-2.22, P=0.041) and myocardial infarction (HR=3.31, 95%CI 1.72-6.37, P<0.001) were independently associated with cardiovascular death. Conclusions: In anticoagulated nonvalvular AF patients, ischemic stroke represents only a small subset of deaths, whereas worsening heart failure is the most common cause of cardiovascular deaths. Heart failure, ischemic stroke/TIA, and myocardial infarction are associated with increased mortality.

[Efficacy and safety of catheter ablation in patients with new-onset atrial arrhythmia after surgical excision of left atrial myxoma]

Objective: To evaluate the safety and efficacy of catheter ablation in patients with new-onset atrial arrhythmia after surgical excision of left atrial myxoma. Methods: Nine patients with new onset atrial arrhythmia and a prior history of left atrial myxoma, who received surgical myxoma excision and catheter ablation between September 2014 and November 2019, were included in the present study. Baseline characteristics, procedural parameters during catheter ablation, severe perioperative adverse events, recurrence rate of arrhythmia and clinical prognosis were analyzed. Kaplan Meier survival analysis was used to define the maintenance rate of sinus rhythm after catheter ablation in this patient cohort. Results: Nine patients were included. The average age was (55.8 ± 9.1) years old (3 male), there were 3 patients (3/9) with paroxysmal atrial fibrillation (PAF) and 6 patients (6/9) with atrial flutter or atrial tachycardia (AFL or AT). Ablation was successful in all patients, there were no perioperative complications such as stroke, pericardial effusion, cardiac tamponade, vascular complications or massive hemorrhage. During a mean follow-up time of 40.0 (27.5, 55.5) months, sinus rhythm was maintained in six patients (6/9) after the initial catheter ablation. The overall sinus rhythm maintenance rate was 2/3. In addition, 1 out of the 3 AF patients (1/3) developed recurrence of AF at 3 month after ablation, and 2 out of the 6 AFL or AT patients (2/6) developed late recurrence of AF or AFL (19 months and 29 months after ablation), two out of three patients with recurrent AFs or AFL received repeated catheter ablation and one patient remained sinus rhythm post repeat ablation. Meanwhile, there was no recurrence of atrial myxoma, no death, stroke, acute myocardial infarction and other events during the entire follow-up period. Conclusions: Catheter ablation is a safe and feasible therapeutic option for patients with new-onset atrial arrhythmia after surgical excision of left atrial myxoma.

[The thromboembolism risk of low-risk atrial fibrillation patients with different clinical characteristics]

Objective: This study explored the thromboembolism risk of low-risk atrial fibrillation (AF) patients (CHA₂DS₂-VASc score of 0 or 1 for male and 1 or 2 for female) with different clinical characteristics to provide the basis for anticoagulation decision-making in these patients. Methods: We prospectively enrolled consecutive 2 862 nonvalvular low-risk AF patients between August 2011 to December 2018 in China-AF (China Atrial Fibrillation Registry) Study, their CHA₂DS₂-VASc score was 0 or 1 for male and 1 or 2 for female. According to their age, sex, presence or absence of hypertension, diabetes mellitus, congestive heart failure, and vascular disease at the time of enrolling, patients were divided into CHA₂DS₂-VASc score 0 score group, 1 score group, and 2 score group. Patients were followed up every 6 months by outpatient clinic visit or telephone interview. The outcome was a thromboembolic event, including ischemic stroke and systemic embolism. Univariate Cox regression analysis was used to compare the thromboembolism risk between the patients with different risk factors and CHA₂DS₂-VASc score 0 group. Results: A total of 2 862 low-risk atrial fibrillation patients were enrolled in this study. 915 patients (32.0%) were female, and age was (55.0±10.7) years old. There were 933 patients (32.6%) in CHA₂DS₂-VASc score 0 group, 1 401 patients (49.0%) in score 1 group and 528 patients (18.5%) in score 2 group. During follow-up (median 1.5 years, 5 811.82 person-years), 33 cases of thromboembolic events were recorded, the annual rate of thromboembolism was 0.57% (95%CI 0.40%~0.80%). The number of thromboembolic events in patients with CHA₂DS₂-VASc score 0, 1 and 2 were 8, 11 and 14, respectively, and the annual thromboembolism event rates were 0.40% (95%CI 0.20%-0.81%), 0.39% (95%CI 0.22%-0.71%) and 1.34% (95%CI 0.80%-2.27%), respectively. The risk of thromboembolism of CHA₂DS₂-VASc score 2 group (HR=3.53, 95%CI 1.48-8.44; P=0.005), especially female patients aged 65-74 years in CHA₂DS₂-VASc score 2 group (HR=2.67, 95%CI 1.63-4.38; P<0.000) was significantly higher than that in patients of CHA₂DS₂-VASc score 0 group. Conclusion: Low-Risk Atrial Fibrillation patients with CHA₂DS₂-VASc score 2, especially female patients aged 65-74 years old with CHA₂DS₂-VASc score 2 are at higher risk of thromboembolism in low-risk AF patients. For such patients, intensified oral anticoagulant therapy might be helpful to reduce the risk of thrombolism.

[Association between weight control and recurrence of atrial fibrillation after catheter ablation in overweight and obese patients]

Objectives: This study explored the relationship between weight control and atrial fibrillation (AF) recurrence after catheter ablation in overweight and obese patients. Methods: We prospectively enrolled consecutive 333 overweight and obese patients aged 28 to 87 years old, who underwent catheter ablation for AF in Beijing Anzhen Hospital between October 2015 and February 2016. Data of patients' characteristics, laboratory examination and treatment were collected at baseline. Each patient was followed up at 3, 6 and 12 months after ablation to collect information on weight, AF recurrence, stroke, major bleeding, hospitalization for cardiovascular reasons and death, etc. Patients were divided into weight controlled group (ΔBMI<-1 kg/m(2)) and weight uncontrolled group (ΔBMI≥-1 kg/m(2)), according to the changes in the most recent exposure BMI before AF recurrence in patients with recurrence or the BMI at 12 months' follow-up in patients without recurrence and the BMI at baseline. Multivariate logistic regression was performed to adjust other known risk factors of AF recurrence and to explore the association between weight control and AF recurrence after catheter ablation. Results: There were 54 patients in weight controlled group and 279 patients in weight uncontrolled group. There were no significant differences in age, gender, education level, left atrial size and history of hypertension between the two groups (all P>0.05). The proportion of patients using angiotensin-converting enzyme inhibitors/angiotensin receptor blockers was higher in the weight controlled group (50.0%(27/54) vs. 34.8%(97/279), P=0.034). However, there was no significant difference in the proportion of patients with obesity (33.3% (18/54) vs. 29.7% (83/279)), paroxysmal AF (59.3% (32/54) vs. 56.6% (158/279)) and AF duration less than 5 years (76.9% (40/52) vs. 65.4% (178/272)) between the weight controlled group and the uncontrolled group. During 1-year follow-up after ablation, the recurrence rate of AF was significantly lower in the weight controlled group than that in the weight uncontrolled group (14.8% (8/54) vs. 32.6%(91/279), P=0.009). Multivariable logistic regression analysis shows that weight control is independently associated with a lower postoperative AF recurrence rate (OR=0.40, 95%CI 0.18-0.90, P=0.026). Conclusion: Weight control is strongly associated with a lower AF recurrence rate after catheter ablation in overweight and obese patients.

[Changes in renal function after catheter ablation in patients with persistent atrial fibrillation]

Objective: The aim of the study was to evaluate the changes and outcome of kidney function after catheter ablation in patients with persistent atrial fibrillation (PAF). Methods: A total of 146 patients with PAF underwent primary atrial fibrillation (AF) ablation were enrolled from January 2013 to December 2014 and followed up. The subjects were divided into the AF recurrence and AF non recurrence groups. The estimated glomerular filtration rate (eGFR) was calculated and serum creatinine levels were detected before ablation and during follow-up. Renal failure was defined as ≥ 25% decline in eGFR. Kaplan-Meier survival curves was applied for the incidence of renal failure. Cox proportional hazards models were conducted to assess the relationship between recurrence of AF and renal failure. Results: After (16.3±11.8) months of follow-up, the eGFR in patients with no recurrence of AF was higher than that in patients with recurrence. eGFR and ΔeGFR in patients with no AF recurrence differed significantly from those in patients with recurrence [(114.15±18.24) ml·min(-1)·1.73m(-2) vs. (98.64±24.09) ml·min(-1)·1.73m(-2), and (7.42±6.36) ml·min(-1)·1.73m(-2) vs. (-11.40±10.19) ml·min(-1)·1.73m(-2), all P<0.001]. The incidence of the renal failure was significantly lower (4.41% vs. 16.67%, P<0.05) and the survival prognosis was significantly better in patients with no recurrence than those in patients with recurrence (χ(2)=5.965, log-rank P=0.05). The multivariate Cox regression analysis revealed that age, baseline eGFR, recurrences of AF and diabetes were independent predictors of the renal failure, with the HR 1.152, 1.086, 13.442 and 6.076, respectively. Conclusions: PAF patients with no recurrence after ablation had a better renal function than those with recurrence, and the recurrence of AF is associated with the deterioration of kidney function in patients with PAF.

[A multicenter prospective controlled study of catheter ablation for patients with persistent atrial fibrillation using domestic 3D cardiac electrophysiological mapping system]

OBJECTIVE

To verify the safety and efficacy of the domestic 3D cardiac electrophysiological mapping system for catheter ablation of persistent atrial fibrillation (AF).

METHODS

From December 2011 to April 2014, 255 patients (184 male) with persistent AF in 13 centers were enrolled in this multicenter prospective controlled study.The patients were allocated to catheter ablation group (experiment group) and antiarrhythmics drugs cardioversion group (control group) with the ratio 2∶1 according to the patients' intention. Left atria were constructed with 3D cardiac electrophysiology mapping system, magnetic sensored saline irrigated radiofrequency ablation catheter (FireMagic™ Cool 3D) and surface reference (Columbus™). Pulmonary vein isolation and left atrial roof line, mitral annulus isthmus line, three tricuspid annulus isthmus line, superior vena cava, the coronary sinus and complex atrial fragmented potentials were targeted if necessary under the guidance of the 3D mapping system. Antiarrhythmics drugs (except amiodarone) were applied to patients for 2 to 3 months after ablation. The patients were followed up for 9 months after 3 months blanking period. The patients in the control group underwent cardioversion with amiodarone and electrical cardioversion if needed. Patients in the control group were also followed up for 9 months.

RESULTS

Of the 255 patients, 167 cases were in the experiment group and 88 cases were in the control group. In per protocol set (PPS), 155 cases were in the experiment group, 79 cases in the control group. Catheter ablation was successful for all patients in the experiment group under the guidance of the 3D cardiac electrophysiological mapping system. Pumononary veins isolation was achieved in all patients. After 9 months follow-up beyond blanking period, in full analysis set, the success rate was 66.5% (111/167) in the experiment group, which was significantly higher than that in the control group (21.6% (19/88), P<0.001). In PPS, the success rate was also significantly higher in the experiment group than in the control group (67.1% (104/155) vs. 22.8%(18/79), P<0.001). The incidence of adverse events was 19.8% in the experiment group and 13.6% in the control group(P=0.223). The adverse events associated with catheter ablation included 1 case of left subclavian hematoma, 1 case of left subclavian bleeding and 1 case of pericardial effusion, which was alleviated by pericardiocentesis. No pulmonary vein stenosis occurred.

CONCLUSION

Domestic 3D cardiac electrophysiological mapping system can safely and effectively guide catheter ablation of persistent AF.

Cranial neurotransmitter alteration in newborn piglets exposed to oxygen

BACKGROUND

To evaluate the influence of hyperoxia on neurotransmitters in the developing brain of newborn piglets.

METHODS

Ten newborn piglets were randomly assigned to hyperoxia (inhaled 100% oxygen) or control (inhaled room air) groups and ventilated for 4 hours. Blood samples were obtained at 0, 15, 30, and then every 30 minutes for 4 hours. Extracts of whole brain tissue were assayed for dopamine, serotonin, and their metabolites using high-performance liquid chromatography.

RESULTS

In comparison with the control group, there was a general trend of lower neurotransmitter content in the brains of the hyperoxia group. In addition, the levels of dopamine and 3,4-dihydroxyphenylacetic acid in the left frontal lobe, and serotonin in the right occipital lobe and left frontal lobe, of the hyperoxia group were significantly lower compared with the control group (p < 0.05).

CONCLUSION

The results indicate that hyperoxia may alter the production or metabolism of dopamine and serotonin in some cortical areas of the neonatal central nervous system, and it tended to have some inhibitory effects. Therefore, pediatricians should be very judicious in using high oxygen on the developing brain.

The paracrine effect of exogenous growth hormone alleviates dysmorphogenesis caused by tbx5 deficiency in zebrafish (Danio rerio) embryos

BACKGROUND

Dysmorphogenesis and multiple organ defects are well known in zebrafish (Danio rerio) embryos with T-box transcription factor 5 (tbx5) deficiencies, mimicking human Holt-Oram syndrome.

METHODS

Using an oligonucleotide-based microarray analysis to study the expression of special genes in tbx5 morphants, we demonstrated that GH and some GH-related genes were markedly downregulated. Zebrafish embryos microinjected with tbx5-morpholino (MO) antisense RNA and mismatched antisense RNA in the 1-cell stage served as controls, while zebrafish embryos co-injected with exogenous growth hormone (GH) concomitant with tbx5-MO comprised the treatment group.

RESULTS

The attenuating effects of GH in tbx5-MO knockdown embryos were quantified and observed at 24, 30, 48, 72, and 96 h post-fertilization. Though the understanding of mechanisms involving GH in the tbx5 functioning complex is limited, exogenous GH supplied to tbx5 knockdown zebrafish embryos is able to enhance the expression of downstream mediators in the GH and insulin-like growth factor (IGF)-1 pathway, including igf1, ghra, and ghrb, and signal transductors (erk1, akt2), and eventually to correct dysmorphogenesis in various organs including the heart and pectoral fins. Supplementary GH also reduced apoptosis as determined by a TUNEL assay and decreased the expression of apoptosis-related genes and proteins (bcl2 and bad) according to semiquantitative reverse-transcription polymerase chain reaction and immunohistochemical analysis, respectively, as well as improving cell cycle-related genes (p27 and cdk2) and cardiomyogenetic genes (amhc, vmhc, and cmlc2).

CONCLUSIONS

Based on our results, tbx5 knockdown causes a pseudo GH deficiency in zebrafish during early embryonic stages, and supplementation of exogenous GH can partially restore dysmorphogenesis, apoptosis, cell growth inhibition, and abnormal cardiomyogenesis in tbx5 knockdown zebrafish in a paracrine manner.

Evaluation of MR spectroscopy and diffusion-weighted MRI in detecting bone marrow changes in postmenopausal women with osteoporosis

AIM

To prospectively investigate the role of MR spectroscopy (MRS) and diffusion-weighted magnetic resonance imaging (DWI) in assessing vertebral marrow changes in postmenopausal women with osteoporosis.

MATERIALS AND METHODS

Seventy-eight postmenopausal women (mean age 63.7+/-3.5 years; range 55-81 years), who underwent dual-energy x-ray absorptiometry of the spine, were divided into three bone density groups (24 with normal, 25 with osteopaenic, and 29 with osteoporotic) based on T score. Both MRS and DWI of the L3 vertebral body were performed to calculate the marrow fat content and apparent diffusion coefficient (ADC). The results were compared between three groups and correlated with BMD.

RESULTS

Vertebral marrow fat content was significantly increased in the osteoporotic group (59.97+/-5.78%), when compared with that of the osteopaenic group (53.04+/-7.66%, p=0.001) and the normal bone density group (48.79+/-7.1%, p<0.001). ADC values in the osteoporotic, osteopaenic, and normal bone density groups were 0.39+/-0.02x10(-3)mm(2)/s, 0.41+/-0.02x10(-3)mm(2)/s, and 0.47+/-0.03x10(-3)mm(2)/s, respectively, with statistically significant difference (P<0.001). A statistically significant positive correlation between T scores and ADC existed (r=0.835, p<0.001). The vertebral marrow fat content was negatively correlated to the bone density (r=-0.639, p<0.001) and to marrow ADC (r=-0.554, p<0.001).

CONCLUSION

The postmenopausal women with osteoporosis exhibited a corresponding increase in vertebral marrow fat content as the bone density decreased. Marrow fat content and ADC were related to the bone density. MRS and DWI are helpful in evaluating the bone marrow changes in postmenopausal women.

Molecular cloning and characterization of full-length cDNAs encoding a novel high-molecular-weight Dermatophagoides pteronyssinus mite allergen, Der p 11

BACKGROUND

Dermatophagoides pteronyssinus (Dp) and D. farinae (Df) mites are the most important source of indoor aeroallergens. Most Dp mite allergens identified to date have relatively low molecular weights (MWs). Identification of high-MW mite allergens is a crucial step in characterizing the complete spectrum of mite allergens and to provide appropriate tools for diagnostic and therapeutic application.

METHODS

The full-length Der p 11 cDNA clone was isolated using cDNA library immunoscreening, the 5'-3' rapid amplification of cDNA ends (RACE) system and polymerase chain reactions (PCR). The whole cDNA insert and its PCR-derived DNA fragments (p1 to p4) were generated and expressed in the Escherichia coli expression system. The allergenicity of the recombinant protein and its peptide fragments was examined by IgE immunodot assays. The IgE-binding reactivity of rDer p 11 was analyzed in the serum of 50 asthmatic children with positive reactivity to Dp mite extract. Its recombinant peptide fragments were also examined by immunodot assays in 30 mite-allergic children.

RESULTS

Der p 11 cDNA consists of a 2625-bp open reading frame encoding a 103-kDa protein with 875 amino acids. It exhibits significant homology with the paramyosin of other invertebrates. The protein sequence alignment of this newly identified Dp mite allergen (denominated as Der p 11) revealed over 89% identity with Der f 11 and Blo t 1. Among 50 Dp-sensitive asthmatic children, rDer p 11 showed positive IgE-binding reactivity to 39 patients (78%). Using immunodot assays, multiple human IgE-binding activities were demonstrated in all four fragments of Der p 11. Using immunoblot assays, the dominant IgG-binding epitope for monoclonal antibody (mAb642) was located in fragment p3 only. In immunoblot assays, cross-inhibition between rDer p 11 and rDer f 11 was up to 73-80% at concentrations of 100 microg/ml.

CONCLUSIONS

This study confirms that the newly identified recombinant Der p 11 is a novel and important high-MW Dp mite allergen for asthmatic children. Our data also indicates that human IgE-binding major epitopes are scattered over the entire molecule of Der p 11.

Serum specific IgE reactivity to recombinant Der f 11 in asthmatic children

This study was designed to examine the prevalence of positive serum IgE reactivity to the recombinant group 11 Dermatophagoides farinae allergen (rDer f 11) in asthmatic children in Taiwan. Using immunoblot analysis in a preliminary study of 18 asthmatic children, 13 (72.2%) reacted positively to rDer f 11 and 16 (88.9%) showed positive reactivity to D. farinae extracts. The allergenicity of rDer f 11 was further evaluated with in vivo skin tests and in vitro IgE immunodot assays in 24 mite skin-test-positive asthmatic children. Whereas 17 (70.8%) had positive skin tests to rDer f 11, 18 (75.0%) had positive serum IgE reactivity to rDer f 11. A good coincidence (87.5%) between the immunodot assay and the skin test was confirmed in these asthmatic children. Moreover, the prevalence of serum IgE reactivity to rDer f 11 was further investigated in a large panel of 49 mite skin-test-positive asthmatic children. Again, 38 (77.6%) had positive serum IgE reactivity to rDer f 11 in immunodot assays. Taken together the positive IgE reactivity to rDer f 11 in immunodot analysis ranged from 75 to 77.6% in two groups of 73 mite skin-test-positive asthmatic children. High incidence of serum IgE antibodies specific for rDer f 11 in the present study suggests that Der f 11 is a novel major allergen of house dust mites.

Interleukin-1beta and tumor necrosis factor-alpha in cerebrospinal fluid of children with bacterial meningitis

Certain cytokines may contribute to the sequence of events that lead to meningeal inflammation in bacterial meningitis. The purpose of this study was to determine the levels of cytokines in the cerebrospinal fluid (CSF) of children with bacterial meningitis and aseptic meningitis of different etiologies. We determined the concentrations of interleukin-1beta (IL-1beta) and tumor necrosis factor (TNF-alpha) in the CSF of 171 specimens of 144 patients whose cases were classified as follow: bacterial meningitis (n=23), aseptic meningitis (n=26) and non-meningitis (n=95). The detectable IL-1beta concentration (> or =20 pg/ml) in the bacterial meningitis, aseptic meningitis and non-meningitis groups were observed with 78.3%, 3.8%, and 8.4%, respectively. Significantly higher serum IL-1beta concentrations were detected in those with bacterial meningitis than those with aseptic meningitis (538.93+/-605.32 pg/ml vs 2.52+/-11.57 pg/ml; P<0.001) or among non-meningitis subjects (2.90+/-11.91 pg/ml; P<0.001). The mean TNF-alpha concentration was 148.74+/-338.77 pg/ml. There was significantly more TNF-alpha than aseptic meningitis (6.85+/-17.93 pg/ml; P<0.001) or non-meningitis (7.67+/-16.07 pg/ml; P<0.001). With regard to diagnosis, measurement of IL-1beta and TNF-alpha levels showed sensitivities of 78% and 74%, respectively; specificities of 96% and 81%, respectively. It is suggested that the levels of these cytokines, especially IL-1beta and TNF-alpha, are useful markers for distinguishing bacterial meningitis from aseptic meningitis.

Pulmonary function during exercise in obese children

BACKGROUND

Obesity imposes additional stress to ventilation during exercise. The purpose of this study is to evaluate the pulmonary function changes with graded exercise and the habitual level of physical activity in obese children.

METHODS

This study recruited 42 obese and 10 normal students, aged 11, from Tamsui Elementary School. Measurements of cardiopulmonary fitness were recorded after a jump rope test. Height, weight and body mass indices were determined before testing.

RESULTS

A significant correlation was found between triceps skin-fold thickness and the body mass index (BMI; r = 0.65, p < 0.05). Blood systolic pressure significantly increased in the obese subjects in their post-exercise test. There was no significant difference between the obese and the non-obese groups in any of the lung function test measurements. Forced expiratory volume in the first second (FEV1), peak expiratory flow rate (PEFR) and forced vital capacity (FVC) were similar in both groups.

CONCLUSIONS

Physiologic responses are not sufficiently different from between the obese subjects and the non-obese children. We should pay more attention to fostering confidence in the obese child exercise.

Serum interleukin-6 and tumor necrosis factor-alpha concentrations in children with mycoplasma pneumonia

A prospective study was performed to assess the relationship among interleukin-6, tumor necrosis factor-alpha, C-reactive protein serum concentrations, and the severity of mycoplasma pneumonia in 49 children. Mycoplasma pneumonia was diagnosed by chest film and anti-Mycoplasma pneumoniae IgM antibody test. Serum concentrations of interleukin-6 and tumor necrosis factor-alpha were measured by using enzyme-linked immunosorbent assays. Interleukin-6 serum levels in mycoplasma pneumonia patients with fever for more than 3 days (41.98 +/- 67.46 [SD] pg/mL) were significantly higher than those in patients with fever < or = 3 days (10.01 +/- 11.74 pg/mL, p < 0.05). Interleukin-6 serum levels in those patients whose chest films revealed patchy consolidations or pleural effusion (58.11 +/- 92.19 pg/mL) were significantly higher than those in patients whose chest films revealed peribronchial interstitial infiltration (15.94 +/- 20.81 pg/mL, p < 0.05). The mean levels of serum tumor necrosis factor-alpha were not statistically significant in the different duration of fever and chest film findings. These results suggest that interleukin-6 serum concentration, rather than tumor necrosis factor-alpha, may be a potential indicator of the severity and outcome of mycoplasma pneumonia.

Comparison of conventional phototherapy and fiberoptic phototherapy in the very-low-body-weight infants

Phototherapy is effectively employed for the treatment of neonatal hyperbilirubinemia, but it may influence the physiological hemodynamics of the infants, such as skin blood flow, insensible water loss and the redistribution of cardiac output. This is a retrospective chart review study involved totally 42 very low birth weight prematures(birth body weight less than 1500 gm, VLBW) who received conventional or fiberoptic phototherapy. Infants with congenital malformation, severe cardiorespiratory instability and the requirement of diuretics, inotropics or blood transfusion were excluded. The body weight loss, daily intake/output and bilirubin level during the initial four days of phototherapy were analyzed. The results showed the efficacy of both methods was the same, while the fiberoptic therapy group had significantly more urine output(p < 0.05), the body weight loss was not statistically significant. It is possible that the fiberoptic therapy group had less insensible water loss and less attenuation of the decrease of renal blood flow, this resulted in more urine output.

Prevalence and relationship between allergic diseases and infectious diseases

In order to determine the prevalence of childhood allergic diseases, infectious diseases, and the relationship between them, 8723 children from three junior high schools in Tou-Cheng City, Taipei County, were studied using questionnaires developed according to the International Study of Asthma and Allergies in Childhood (ISAAC) criteria combined with supplementary questions about infectious diseases. Students and their parents completed the questionnaires at home. The age of the children ranged from 10 to 18 years old (14.12 +/- 0.89 years), the majority (96.03%) was aged from 13 to 15 years old. The 12-month prevalences of self-reported allergic disease symptoms were: asthma symptom 8.2%, allergic rhinitis symptom 39.6%, and atopic dermatitis symptom 5.9%. The prevalences of diagnosis of the allergic diseases were: asthma 8.7%, allergic rhinitis 24.1%, and atopic dermatitis 3.9%. The 12-month prevalences of diagnosis of infectious diseases were: pneumonia 0.6%, bronchitis 7.2%, sinusitis 7.2%, purulent conjunctivitis 2.5%, otitis media 4.3%, encephalitis or meningitis 0.4%, gastroenteritis 14.5%, acne 23.9%, purulent dermatitis 1.3%, and other infectious diseases 1.2%. Lifetime admission rates of children due to infectious diseases were: pneumonia 1%, bronchitis 1.8%, sinusitis 0.3%, purulent conjunctivitis 0.2%, otitis media 0.3%, encephalitis or meningitis 0.3%, gastroenteritis 2.1%, and other infectious diseases 0.6%. The prevalence of infectious diseases was significantly higher in children with allergic disease symptoms (defined as asthma, allergic rhinitis, or atopic dermatitis). These results demonstrated the presence of a link between allergic diseases and infectious diseases, which may have some important clinical implications.

Soluble interleukin-2 receptor and interleukin-4 in sera of asthmatic children before and after a prednisolone course

BACKGROUND

Cytokine-mediated interactions among inflammatory cells may play a role in the pathogenesis of bronchial asthma.

OBJECTIVE

To understand the role of soluble interleukin-2 receptor (sIL-2R) and interleukin-4 (IL-4) in the disease activity of acute asthma, changes in serum concentrations of sIL-2R and IL-4 elaborated by activated T-lymphocyte before and after prednisolone therapy with clinical improvement were determined in the present study.

METHODS

Circulating levels of sIL-2R and IL-4 in sera from 15 normal control subjects and in sera from 20 allergic asthmatic children with acute exacerbation and in a stable condition were determined by using commercially available ELISA kits.

RESULTS

The mean concentration of serum sIL-2R was significantly higher in acute exacerbation than in children with stable asthma (368.9 +/- 395.4 pg/mL vs 291.2 +/- 361.0 pg/mL; P < .01) or in control subjects (124.6 +/- 17.8 pg/mL; P < .001). The mean concentration of serum IL-4 was higher in acute exacerbation (5.82 +/- 1.10 pg/mL) and in stable asthmatic patients (6.73 +/- 2.83 pg/mL) versus control group subjects (5.54 +/- 1.20 pg/mL). However, the difference was not statistically significant among the three study groups.

CONCLUSIONS

This study provides further evidence that changes in serum IL-2R may serve as an objective indicator for clinical outcome of allergic asthmatic patients.

Serum levels of eosinophil cationic protein and eosinophils in asthmatic children during a course of prednisolone therapy

Eosinophils play an important role in the inflammatory events of allergic asthma. Serum eosinophil cationic protein (ECP) is a marker of disease activity and of treatment efficacy in bronchial asthma. To understand the role of ECP concentrations in disease activity of acute asthma, we determined changes in serum concentrations of ECP elaborated by activated eosinophil before and after prednisolone therapy. Circulating levels of ECP in 15 normal control subjects, and in sera of 20 asthmatic children who were allergic to house dust mites, were measured during an acute exacerbation and when the children were in stable condition, using commercially available assay kits. The mean concentrations of serum ECP were significantly higher during an acute asthma exacerbation than when the children were stable (26.41 +/- 21.66 microg/L vs 15.74 +/- 11.36 microg/L P < 0.01) or when compared to control subjects (7.50 +/- 1.42 microg/L; P < 0.001). The mean eosinophil counts (EC) during acute asthma attacks (575 +/- 286/mm3) and when stable (467 +/- 204/mm3) were higher than in the control group (181 +/- 164/mm3). The differences were statistically significant among the three groups (P < 0.05). A significant correlation was found between serum levels of ECP and EC (r = 0.788, P = 0.001) in asthmatic children; there were also significant correlations between ECP and EC in nonallergic normal control subjects (r = 0.662; P = 0.007). In conclusion, this study provides further evidence that changes in serum ECP may serve as an objective indicator for clinical activity and results of treatment in allergic asthmatics.

The evaluation of allergens and allergic diseases in children

Knowing the incidence of allergic diseases and their relationship with allergens is a crucial requirement for therapeutic judgment. We present our experience on the incidence, clinical features and allergens of the allergic diseases detected by multiple allergosorbent chemiluminescent assay (MAST-CLA) in children from 1997 to 1999 at the Taipei Veterans General Hospital. The incidence of bronchial asthma, allergic rhinitis and atopic dermatitis are significantly different when stratified by age groups. Among the enrolled 2008 patients, 980 (48.8%) patients have positive MAST-CLA results. Of these, 562 (57.3%) are male and 418 (42.7%) are female. A significant increase among patients with positive allergens is also found when stratified by age group. Inhalant allergen is the major allergen detected in our patients. House dust mites Dermatophagoides pteronyssinus (Dp) and Dermatophagoides farinae (Df), cockroaches, feathers, and dog dander show the highest incidence in the 7- to 12-year-old group. In the fungal group, Aspergillus and Penicillium also show a significant difference in the incidence among different age groups. Pollen allergens, on a whole, show significant difference in incidence among different age groups. The food allergen group shows variable significant difference in incidence. Crab, milk, and egg white show the highest significant incidence in the 2- to 6-year-old group. These results suggest that the incidence of allergens detected in allergic diseases varies among different age groups.

Evaluation of different blood culture media in neonatal sepsis

Blood drawn from neonatal patients is available in only limited amounts for blood cultures. The BACTEC Pediatrics (PEDS) Plus aerobic nonradiometric blood culture bottle was designed to aid the diagnosis of pediatric bacteremia. To assess the value of PEDS Plus blood culture medium for neonatal patients, we prospectively compared the PEDS Plus blood culture medium with the standard BACTEC aerobic medium (NR6A). From January to December 1999, 192 pairs of PEDS Plus and NR6A blood culture bottles were collected by the pediatric microbiology laboratory of Taipei Veterans General Hospital. Seventeen (8.85%) isolates were considered to be clinically significant microorganisms. Isolation rate of the PEDS Plus culture bottles was significantly higher than that of the NR6A culture bottles (p < 0.001). Six isolates were detected at least 1 day earlier by using the PEDS Plus culture bottles (p < 0.001). Among those patients who were under antibiotic therapy, the PEDS Plus culture bottle showed more significant growth than the NR6A culture bottle (p < 0.001). After weighing their benefits, we suggest substituting PEDS Plus bottles for NR6A bottles when culturing blood from neonatal patients or from those who are receiving antibiotic therapy.

Evaluation of serum interleukin-8 as a marker of disease activity in acute asthma in children

Cytokine-mediated interactions among the inflammatory cells may play a role in the pathogenesis of bronchial asthma. Interleukin-8 (IL-8) is a major cytokine in the recruitment of neutrophils to the area of inflammation. Serum IL-8 is a marker of disease activity and treatment efficacy in bronchial asthma. To understand the role of IL-8 in disease activity in acute asthma, changes in serum concentrations of IL-8 elaborated by activated eosinophil before and after prednisolone therapy with clinical improvement were determined in the present study. Circulating levels of IL-8 in 15 normal control subjects and in sera from 20 allergic asthmatic children with acute exacerbation and in stable condition were determined by using commercially available assay kits. The mean concentration of serum IL-8 was statistically significantly higher in asthmatic children with acute exacerbation (63.62 +/- 11.41 pg/mL) and in stable asthmatics (64.22 +/- 10.31 pg/mL) compared to the control group subjects (50.40 +/- 30.70 pg/mL; p < 0.01). However, the difference was not statistically significant between the acute exacerbation and stable asthmatics groups (p > 0.05). Serum IL-8 is a poor indicator of disease activity in acute asthma; therefore, monitoring by serum IL-8 concentration is of limited value. The clinical value of serum IL-8 as a marker of disease activity remains to be established.

Significance of specific IgG subclass antibodies to house dust mites in asthmatic children

BACKGROUND

Dermatophagoides pteronyssinus (Dp) and Dermatophagoides farinae (Df), the major components of house dust, are considered to be etiologic factors of extrinsic asthma. The relationships between immunoglobulin (Ig) G subclass antibodies specific for Dp (or Df) were compared in specific IgE-positive and -negative asthmatic children.

METHODS

Serum levels of IgG and IgE subclass antibodies specific for Dp and Df were studied in 52 children (age, 3-13 years; mean age, 8.4 years) with asthma using enzyme-linked immunosorbent assays. The skin prick test was also used in diagnosis of the reactivity of allergic disease.

RESULTS

The levels of serum-specific IgG1 and IgG2 to Dp and Df in mite-specific IgE-(or skin-test) positive asthmatic children were significantly higher than those in mite-specific IgE- (or skin test) negative children (p < 0.01). Significant correlations between the level of the specific IgE and IgG1 (r = 0.6067; p = 0.0001) or IgG2 (r = 0.5851; p = 0.0002) to Dp, and IgG1 (r = 0.3823; p = 0.0214) or IgG2 (r = 0.5057; p = 0.0017) to Df were found. The specific IgE level and skin test reactivity showed a high correlation of greater than 96% (50/52).

CONCLUSIONS

The levels of mite-specific IgG subclasses were partially compatible to specific IgE levels and skin test reactivity. We conclude that house dust mite allergy is significantly associated with specific IgG1, IgG2 and IgE responses.

Isolation of Aeromonas hydrophila in children with diarrhea

Aeromonas species are gram-negative bacilli that lead to a wide spectrum of infectious diseases in human. In the present study, these bacilli were reviewed to assess their significance as enteric pathogens in this area. During the years of 1994 to 1998, the clinical microbiology laboratory received 2150 stool specimens of children with diarrhea. Medical charts of patients who had positive culture for Aeromonas hydrophila were reviewed. A. hydrophila were isolated from 50 (2.3%) of 2150 children with diarrhea. Most patients were outpatients with ages ranging from 5 months to 16 years old (mean age 3.5 years). The male to female ratio was 0.85:1. All patients suffered from watery or loose diarrhea, some with blood-tinged stool. Whether or not they received medication, all patients had uneventful recoveries. The results of antibiotic susceptibility testing revealed that all strains were not susceptible to ampicillin. In summary, A. hydrophila may be considered as a causative agent of gastrointestinal illness in children.

Cytomegalovirus pericarditis with cardiac tamponade in a young infant

The principal viruses implicated in pericarditis are enteroviruses. Cytomegalovirus pericarditis is quite rare and has been reported in immunocompromised patients with acquired immunodeficiency syndrome, malignant neoplasm or organ transplantation. We report a three-month-old male infant who suffered from cough and rhinorrhea for two weeks. He developed shortness of breath for three days, and fever for one day, prior to admission. Physical examination revealed tachycardia, tachypnea, pale conjunctiva, hepatomegaly, and a muffled heart sound without significant murmur. Chest radiography showed marked enlargement of the cardiac silhouette. Echocardiography demonstrated a large amount of pericardial effusion with impaired diastolic ventricular function. After pericardial drainage and supportive treatment, the fluid gradually disappeared. Viral culture of the pericardial fluid and serologic data confirmed a cytomegalovirus infection. Cytomegalovirus pericarditis should be included in the differential diagnosis of pericardial effusion in a young infant.

The assessment of anaerobic blood culture in children

Over the past 20 years, there has been a decline in the percentage of positive blood cultures yielding anaerobic organisms. Due to the limited blood volume drawn from pediatric patients, we have assessed the value of routine anaerobic blood cultures in children. From January 1994 to December 1998, 9886 paired aerobic and anaerobic blood cultures were analyzed in the pediatric microbiology laboratory at the Taipei Veterans General Hospital. Six hundred and eighteen (6.25%) isolates were considered to be clinically important microorganisms. Staphylococci, streptococci, aerobic gram-negative bacilli, and yeasts showed more significant growth within the aerobic culture than that within the anaerobic culture. Significantly more aerobic gram-positive cocci, aerobic gram-negative bacilli, and yeasts were detected at least 1 day earlier by using the aerobic culture. Three patients with documented anaerobic bacteremia had obvious symptoms related to anaerobic infections. Our study concludes that routine use of anaerobic blood culture in pediatric patients is not necessary. Anaerobic blood cultures should be reserved for patients with diseases like intra-abdominal or oral infections, neutropenic patients on steroid therapy, pressure sores, cellulitis, and human bite wounds.

Tumor necrosis factor-alpha and interleukin-6 profiles in children with pneumonia

Pneumonia is a common cause of hospitalization and is associated with high morbidity in children. Tumor necrosis factor-alpha (TNF-alpha) and Interleukin-6 (IL-6) are primary mediators of inflammation, and have been implicated in a large number of infectious and non-infectious inflammatory diseases. The serum concentrations of TNF-alpha and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA) in 27 patients with bacterial pneumonia (n = 12) or respiratory syncytial virus (RSV) pneumonia (n = 15) and in 15 healthy control subjects. TNF-alpha concentrations of patients with bacterial pneumonia in acute stage (16.94 +/- 5.70 ng/L) were significantly higher than those in convalescent stage (5.80 +/- 0.75 ng/L), in patients with RSV pneumonia (5.06 +/- 0.44 ng/L) and in healthy control subjects (5.39 +/- 0.68 ng/L) (p < 0.005). TNF-alpha concentrations of patients with RSV pneumonia were not significantly different from those of the control group. IL-6 concentrations of patients with bacterial pneumonia in acute stage (465.94 +/- 290.30 ng/L) were significantly higher than those in convalescent stage (22.04 +/- 15.08 ng/L), in patients with RSV pneumonia (7.65 +/- 2.58 ng/L), and in healthy control subjects (0.84 +/- 0.08 ng/L) (p < 0.0005). There was significant difference between patients with RSV pneumonia and the healthy control group (p < 0.005). In summary, there were significant differences in TNF-alpha and IL-6 concentrations between acute stage and convalescent stage in patients with bacterial pneumonia, making them useful as markers for bacterial pneumonia. Further studies are needed to establish the potential diagnostic and prognostic value of TNF-alpha and IL-6.

Isolation and characterization of a novel 98-kd Dermatophagoides farinae mite allergen

BACKGROUND

Exposure to allergens from house dust mites is a significant cause of immediate hypersensitivity. Thus far, the active mite allergens defined are low molecular weight (MW) proteins or glycoproteins. However, other important mite allergens remain to be investigated. In this study a high MW mite antigen with a high IgE-binding activity was characterized.

METHODS

An anti-Dermatophagoides farinae (Df) monoclonal antibody, mAb642, which recognized a 98-kd allergenic mite protein, was used for affinity chromatography. The purified Df642 was characterized biochemically and immunologically.

RESULTS

Competitive ELISA demonstrated that mAb642 was inhibited by the interaction between serum IgE from allergic patients and Df642 antigen in a dose-dependent fashion. The IgE reactivity to both 98-kd and 92-kd components was removed or diminished by preincubation of asthmatic sera with Df642-coated CNBr-activated cellulose-4B gel. Two-dimensional immunoblot analysis revealed that there are at least 4 isoforms of Df642 that represent a minor component in the crude mite extract. The allergenicity of Df642 was assayed by IgE immunoassay with a large panel of 67 sera from asthmatic patients with positive skin reactions, and Df 642 showed positive IgE reactivity with more than 80% of the sera tested. Thus it should be classified as an important allergen. In addition, amino acid sequence analysis revealed that Df642 shares more than 50% homology with paramyosin from invertebrates.

CONCLUSION

We have identified and characterized a 98-kd house dust mite allergen that showed greater than 80% IgE reactivity with sera from patients allergic to mites. This is the first high MW allergen characterized to date, and it shares high sequence homology with paramyosins in invertebrates.

Coxsackievirus B1 infection in infants less than 2 months of age

Most of the neonatal enteroviral infections reported in the literature are associated with Coxsackievirus B2-B5 and echovirus 9 and 11. We report a retrospective Coxsackievirus B1 (CB1) infection in infants less than 2 months of age. Seventeen patients had aseptic meningitis and 8 had systemic sepsis (multi-organ involvement including meningitis, impaired liver function, and abnormality in coagulation). The symptoms and signs were nonspecific and could not be distinguished with bacterial infection on clinical grounds. Virus isolation was mandatory for diagnosis. Impaired liver function and coagulation profiles were noted in patients with systemic sepsis, but not in patients with meningitis only. CSF examination showed some uncommon features of viral meningitis: predominance of polymorphonuclear cells (PMN) was noted in 62.5% of patients and hypoglycorrhachia in 64% of patients. The patients with only meningitis recovered completely without any sequela. One of the eight patients with systemic sepsis died with case fatality rate 12.5%. Physicians should be aware of the possibility of CB1 virus infection in young infants during prevalent seasons. Specimens should be sent for viral culture in patients with meningitis and sepsis to make a definite diagnosis.

Interferon-gamma in cerebrospinal fluid of children with aseptic meningitis

BACKGROUND

Certain cytokines may contribute to the sequence of events that lead to meningeal inflammation in bacterial meningitis. However, their role in viral meningitis is not so less well defined. We determined the cytokines levels in the cerebrospinal fluid (CSF) of children with aseptic meningitis and discussed their relationship with clinical and laboratory findings.

METHODS

We determined the concentrations of interleukin-1 beta (IL-1 beta), interferon-gamma (IFN-gamma) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in the CSF of 62 patients with aseptic meningitis including 17 patients with culture-proved enteroviral meningitis, and from 19 control acute febrile patients without meningitis.

RESULTS

The GM-CSF in the cerebrospinal fluid was detected from one of the 62 patients with aseptic meningitis and none of the 19 controls. Fourteen (23%) of the 62 patients with aseptic meningitis and 2 (10.5%) of 19 controls had detectable IL-1 beta. There was no significant difference in IL-1 beta levels between patients with aseptic meningitis (4.4 +/- 11.4 pg/ml) and control group (2.4 +/- 7.7 pg/ml). The CSF IFN-gamma level was detectable in 40 (65%) of 62 patients and 6 (31.6%) of 19 controls. The mean CSF IFN-gamma concentration was significantly higher in patients with aseptic meningitis when compared with that in control group (37.9 +/- 48.8 pg/ml vs 17.5 +/- 29.7 pg/ml; p = 0.007).

CONCLUSIONS

IFN-gamma was detectable in the CSF in 65% of patients with aseptic meningitis and the role of interferon-gamma remains to be determined.

Determination of the food specific IgE antibodies: comparison of MAST-CLA and CAP systems

BACKGROUND

This study was carried out to compare two techniques used to determine the food specific IgE antibody.

METHODS

Thirty-four allergic patients were evaluated for most common food IgE antibodies by multiple allergosorbent chemiluminescent assay (MAST-CLA). IgE antibodies to eight of these food allergens were also measured by Pharmacia CAP (CAP) test.

RESULTS

The food specific IgE showed good agreement between MAST-CLA and CAP (kappa = 0.3-0.77). The sensitivity of MAST-CLA assay for food specific IgE antibody was variable comparing with that of CAP system. The accuracy ranged from 0.76 to 0.97. The agreement between the results of MAST-CLA and skin test was variable (kappa = 0.03-0.58). The agreement was poor in wheat, peanut and soybean (kappa = 0.03-0.12). Similar result between CAP and skin test was also obtained (kappa = 0.06-0.82). The agreement was poor in wheat (kappa = 0.06) and milk (kappa = 0.15).

CONCLUSIONS

Different results might be related to quality of the extract, how they are performed in vitro test and difference of correspondent allergens employed in the tests.

The clinical evaluation of an outbreak of aseptic meningitis in children

BACKGROUND

Aseptic meningitis is a common disease in children; The present report describes the clinical and laboratory studies of 62 children involved in an outbreak of aseptic meningitis.

METHODS

Sixty-two children with aseptic meningitis having been hospitalized from February to June 1993 were evaluated. The clinical data were obtained by review of the medical records. Initial cerebrospinal fluid (CSF) laboratory values were recorded, and CSF specimens were submitted to determine the viral etiology.

RESULTS

Thirty-three percent of the cases were aged 2-5 years. Echovirus 30 was isolated from CSF specimens in 17 children, this is the only virus isolated from CSF during this period. The illness was characterized by transient fever, headache and vomiting. There was wide variation in the number of leukocyte from 14 to 2333 cell/mm3 in the spinal fluid. CSF protein ranged from 19 mg/dL to 114 mg/dL, and CSF sugar was normal in all specimens. Virus isolation was related to the cell count in CSF. There was no significant relationship between CSF cell count and protein content (r = 0.162, p = 0.2237). Hospital stay ranged from 1 to 14 days with an average of 3.9 days. CONCLUSIONS. The disease was mild and self-limiting without death or complication. Enterovirus isolation from CSF can substantially establish the diagnosis and the subsequent management, therefore, early discharge is expectable.

Fungal infection of ventriculoperitoneal shunts in children

Infection is still the most common complication of shunt procedures in children. However, fungal infection is still considered to be rare. We found that fungi accounted for 17% of shunt infections (8 of 48) in a retrospective study. All of the patients were premature babies and had received a ventriculoperitoneal shunt because of hydrocephalus. The clinical manifestations were subtle and insidious. The time of onset of infection ranged from 1 month to 1 year after the insertion of the shunt. Examination of the cerebrospinal fluid of infected patients showed mild pleocytosis with an elevated protein concentration. Candida species (including Candida albicans, Candida parapsilosis, and Candida tropicalis) or Torulopsis glabrata were isolated. In all but one case, shunts were removed and systemic therapy with amphotericin B was administered. Amphotericin B was given intrathecally to two patients, who did not respond to systemic therapy. Treatment with fluconazole failed for one patient. We suggest performing fungal cultures in cases of shunt infection, especially those involving premature infants. Extraventricular drainage, systemic therapy with amphotericin B, and insertion of a new shunt remain the principal components of the treatment regimen for fungal shunt infections in children.

Comparison between skin testing and in vitro testing for diagnosis of allergen in asthmatic children

BACKGROUND

This study was designed to compare the skin testing and in vitro testing for the diagnosis of most common inhalant allergens in asthmatic children.

METHODS

Sixty-two asthmatic children positive to most common allergens in the area of skin tests and multiple allergosorbent chemiluminescent assay (MAST-CLA) were subjected to another Pharmacia CAP test (CAP).

RESULTS

The agreement between the results of MAST-CLA and CAP was variable. The correlation coefficient for CAP with MAST-CLA was significant for five allergens except candida, dog dander and Willow pollen when the diagnostic levels of MAST-CLA and CAP were compared with skin test reactions. For all the allergens tested, MAST-CLA showed a sensitivity of 51%, a specificity of 84% and an efficiency of 73%, compared with 57%, 80% and 74%, respectively, in the CAP analysis.

CONCLUSIONS

MAST-CLA and CAP can be used as a screening test to measure allergen IgE level. Both MAST-CLA and CAP were comparable in their ability to diagnose of allergy to tested allergens.

Continuous positive airway pressure by nasal prongs in bronchiolitis

Ten infants with evidence of impending respiratory failure from severe bronchiolitis were successfully treated with continuous positive airway pressure (NCPAP) with double nasal prongs. Their mean (SD) age was 6.7 (3.8) months and mean (SD) body weight was 7.1 (2.1) kg. Respiratory assessments were made immediately before and 2 hours after application of NCPAP. Clinical symptoms, signs, and arterial blood gases improved in all patients, with a significant fall in mean (SD) respiratory rate [71 (6) vs. 54 (9) per minute], mean (SD) heart rate (178(9) vs. 154(15) per minute], and mean (SD) partial pressure of arterial carbon dioxide [Paco2; 48.0 (13.9) vs. 42.4 (12.9) mmHg]. There was a significant rise in mean (SD) arterial blood pH [7.33 (0.05) vs. 7.37 (0.05)] and mean (SD) oxygenation ratio [Fio2/Pao2, 155 (25) vs. 175 (22)]. We believe NCPAP is an effective method, with numerous advantages in the treatment of severe bronchiolitis. Early application of NCPAP is suggested to avoid the need for mechanical ventilation.

[Comparison of food specific IgE antibody test (RAST) and skin tests in children with atopic dermatitis]

Thirty children with atopic dermatitis were enrolled in our study to evaluate the food specific IgE antibody assay (RAST) and skin tests as a screening test for food hypersensitivity. Our results showed that eight food antigens (fish, shrimp, crab, soybean, milk, egg-white, peanut, wheat) frequently elicited positive hypersensitivity reactions. Twenty-four patients had at least a positive skin reaction to one of the foods tested. Of the 240 skin tests, 30% (72/240) yield positive reactions. Eighteen patients had at least a positive RAST reaction to one of the foods tested, 20.9% (50/240) yield positive reaction. The agreement between skin test and RAST was 79.6%. Crab and shrimp accounted for most frequent positive reaction in both tests. The skin tests produced more positive results in skin testing than RAST, but gave a higher frequency of false positive results. The diagnosis of food allergy may be suspected from the medical history or by food specific IgE antibodies together with skin test as a screening test. Furthermore, the double blind placebo controlled food challenge should be considered as standard for clinical investigations.

Preirradiation chemotherapy for very young children with brain tumors

Standard management of malignant brain tumors includes either surgical resection alone or surgery followed by irradiation. However, neuroaxis irradiation administered to very young children for primary intracranial tumors is often associated with major late side effects. To delay irradiation and evaluate the efficacy of preirradiation chemotherapy, we treated 9 young children (aged less than 3 years), who had newly diagnosed brain tumors and underwent total or subtotal resection, with a combination of chemotherapy including vinblastine, cisplatin, and etoposide every 3-4 weeks for 6-14 courses between 1988 and 1992. There were malignant gliomas in four patients, medulloblastomas in three, and ependymomas in two. A response to preirradiation chemotherapy (complete remission or partial remission) occurred in seven out of nine cases. Only one patient had progressive disease during the chemotherapy period. Preirradiation chemotherapy with vinblastine, cisplatin, and etoposide might be a highly effective combination allowing delay of radiation therapy in very young children with brain tumors. Acute and subacute toxicity of chemotherapy in this study was mild.

Evaluation of a once-a-day theophylline preparation in asthmatic children

We conducted a study to evaluate the serum theophylline concentrations and dose interval of Theolan preparation in asthmatic children. A series of serum theophylline levels were measured both in 10 asthmatic children taking Theolan once a day and 9 children twice a day. In the once-a-day group, the peak serum theophylline level was greater than 20 micrograms/ml; whereas, in the twice-a-day group, it was mostly between 10 and 20 micrograms/ml. The difference of the peak-to-trough was more fluctuant in the once-a-day group than in the twice-a-day group. These results suggest that Theolan given once a day in the evening can be useful in the management of nocturnal asthma; however, it was difficult for once-a-day administration of Theolan to sustain rigid therapeutic serum theophylline levels. Because of rapid metabolism in children, they may require a more frequent interval than once-a-day dosing to suppress the symptoms of chronic asthma.

Changes in the levels of house dust mite specific IgG4 during immunotherapy in asthmatic children

Serum levels of IgG subclass and house dust mite (Dermatophagoides pteronyssinus, Dpt) specific IgG4 were evaluated during immunotherapy in asthmatic children. Asthmatic children undergoing long-term immunotherapy (more than 2 years) posed a mean value of total serum IgG4 or Dpt-specific IgG4 antibodies significantly higher than that of patients prior to receiving immunotherapy, asthmatic (placebo) controls, or patients undergoing short-term immunotherapy (less than 1 year) (P less than 0.05). The mean levels of serum Dpt-specific IgG4 in all asthmatic groups were also significantly higher than in the non-allergic controls (P less than 0.01). Moreover, the mean level of Dpt-specific IgG4 tended to increase during immunotherapy. A significant correlation between total serum IgG4 and Dpt-specific IgG4 antibodies was noted (r = 0.6243; P less than 0.001). Serial follow-up reveals that Dpt-specific IgG4 levels usually rose significantly with clinical improvement in asthmatic children during immunotherapy. These results suggest that the anti-mite-specific IgG4 antibody may serve as an indicator for clinical outcome of mite allergy during immunotherapy.

A rapid cold agglutinin test in Mycoplasma pneumoniae infection

A definite diagnosis of Mycoplasma pneumoniae infection is currently based on cultural method or complement fixation test which is usually retrospective. A rapid cold agglutinin test was developed to determine its value on the early diagnosis of M. Pneumoniae infection. One hundred and thirty patients with pneumonia aged between 5 and 14 years were studied. Blood specimens from all the patients were collected for rapid cold agglutinin test, cold hemagglutination test, and complement fixation test. Thirty patients showed positive, rapid cold agglutinin test. All the patients with positive rapid cold agglutinin test had higher (greater than or equal to 1:32) cold agglutinin titers which were simultaneously performed. The rapid cold agglutinin test had 100% sensitivity and 97% specificity when a cut-off criterion was set at cold agglutinin titer greater than or equal to 1:64. Twenty-five of the 130 cases were serologically proven to have M. pneumoniae infection using complement fixation test or/and cold agglutinin titer. M. pneumoniae was a major cause (21/28) in cold agglutinin-positive pneumonic patients. The positive predictive value of the rapid cold agglutinin test is 70% (21/30). Only 28% (7/25) of the patients with M. pneumoniae infection were diagnosed at acute stage with serological method. We conclude that the rapid cold agglutinin test is of much value in the early detection of M. pneumoniae infection in office or hospital practice in children with pneumonia.

Expression of serum IL-2, IL-2R, and CD8 levels during hyposensitization in house-dust-sensitive asthmatics

In this study, we used the enzyme-linked immunosorbent assay (ELISA) to evaluate the changes of serum interleukin-2 (IL-2), interleukin-2 receptor (IL-2R), and suppressor/cytotoxicity factor (CD8) in house dust-sensitive asthmatic children during hyposensitization. Patients before immunotherapy presented significantly higher serum levels of IL-2 and IL-2R than normal subjects (p less than 0.001), but these levels became normal after three years of hyposensitization. No significant difference of serum CD8 level was noted between pretreated patients and normal controls. Although the serum CD8 level in treated patients also decreased after three years of immunotherapy, this decrease was not significant compared with the pretreated patients (p greater than 0.05). This study suggests that serum IL-2 and IL-2R markers might be helpful in analyzing allergic states associated with immune activation and in evaluating the therapeutic effects of hyposensitization.

The prevalence of allergic disease and IgE antibodies to house dust mite in schoolchildren in Taiwan

The prevalence of positive specific IgE antibodies to house dust mites (Dermatophagoides pteronyssinus; D. farinae) was determined by enzyme-linked immunosorbent assay (ELISA) in 5097 (61%) volunteers of 8345 schoolchildren aged between 7 and 14 yr from two government schools. All of them filled out a questionnaire concerning allergic symptoms. Among them, 412 (8.1%) children showed a positive reaction to at least one of the two mite allergens, the range varying between 5.6 and 11.2% according to the child's age. Boys had higher prevalence of positive mite specific IgE than girls (9.8% vs. 6.4%, P less than 0.01), with the overall male to female ratio 1.5:1. The prevalence of bronchial asthma in boys and girls was 5.3% and 3.3% respectively. The positive mite specific IgE antibody in children with asthma and allergic rhinitis was 52% (103 of 198) and 28.7% (193 of 673) respectively. The mean levels of mite specific IgE were not significantly related to the age of onset and severity of asthmatic symptoms (P greater than 0.1), but were significantly different among subjects with current and past asthma (P less than 0.001). It is suggested that the mite-specific IgE may play a role in the pathogenesis of bronchial asthma in children.

Changes of serum-specific IgE antibody titer during hyposensitization in mite-sensitive asthmatic children

In this study, we used the enzyme-linked immunosorbent assay (ELISA) to evaluate the changes of IgE antibody titer against Dermatophagoides pteronyssinus (D. pteronyssinus) or Dermatophagoides farinae (D. farinae) in asthmatic children after immunotherapy. According to ELISA analysis, a significantly higher mean level of IgE antibody titer to D. pteronyssinus (or D. farinae) was found in nonhyposensitized asthmatic children than in the pediatric control group (p less than 0.001), but there was no significant difference between the group receiving short course (one year or less) immunotherapy and the group without immunotherapy (p greater than 0.05). We also noted the significant reduction of specific IgE antibody to D. farinae and D. pteronyssinus in the hyposensitized group after long-term immunotherapy; namely, 1.5 and 3 years, respectively, compared with the nontreated group (p less than 0.01). Although D. pteronyssinus-specific IgE antibody decreased less rapidly than D. farinae-specific IgE antibody, both kept decreasing throughout the period of immunotherapy. This study also indicates that the ELISA test may be helpful in screening specific IgE antibodies, diagnosing allergic disease, and evaluating therapeutic effects of hyposensitization.