Changes in anisometropia by age in children with hyperopia, myopia, and antimetropia

Anisometropia is a unique condition of both eyes and it is associated with vision problems such as amblyopia and reduced stereoacuity. Previous studies have not reported its change pattern by age and its correlation with the refractive condition of both eyes. This study aims to compare the changes in anisometropia by age in children with hyperopia, myopia, and antimetropia. In total, 156 children were included. Children aged 3-11 years with anisometropia ≥ 1.00 D were followed up for ≥ 1 year with ≥ 2 visits at two medical centers in Taiwan. Refractive errors by cycloplegic autorefractometry, best-corrected visual acuity, eye position, and atropine use were recorded. The children were divided into hyperopic, myopic, and antimetropic groups. The results showed that anisometropia decreased in children aged < 6 years (3.34-2.96 D; P = 0.038) and increased in older children (2.16-2.55 D; P = 0.005). In children aged 3, 4, 5, and 6 years, the mean anisometropia was higher in children with myopia and antimetropia than in those with hyperopia (P = 0.005, 0.002, 0.001, and 0.011, respectively). The differences were not significant in children aged > 6 years (all P > 0.05). The factors associated with changes in anisometropia were age, refractive group, amblyopia, and strabismus. Anisometropia decreased with age in children younger than 6 years, and the changes in anisometropia was found in children with myopia and antimetropia.

The quality of nutritional information available on popular websites: a content analysis

The overall purpose of this study was to increase knowledge and understanding of the new informational landscape that is emerging on the Internet in relation to nutritional health content in order to provide policy makers with better communication and health promotion tools. We identified the sites most used by Canadians to access nutrition information and conducted content analyses to identify the sources of this nutritional information as well as its quality by systematic comparison with the main guidelines published in the Canada Food Guide. We found that commercial websites accounted for 80% of visits and time spent on seeking health and nutrition information. We also found uneven messaging about fruit and vegetable intake as well as consistent messaging undermining the 'eat a variety of foods' message, which is a central component of the Canada Food Guide. On the positive side, inappropriate or incongruent advice about salt, coffee and alcohol intake was virtually non-existent and advice congruent with the guide was found three times more often than incongruent advice. Finally, the site offering the best advice was a non-commercial government-based site. This site differed from the commercial sites not so much in its ability to deliver the 'right' advice but more in its ability to exclude articles with poor and misleading advice on their sites.

Vulvovaginal carriage of yeasts other than Candida albicans

AIMS

We investigated the spectrum of yeasts isolated, and compared the epidemiological and laboratory characteristics of women carrying vulvovaginal Candida albicans with those carrying yeasts other than C. albicans.

METHOD

Between April and June 2001, 5802 consecutively received genital swabs from women were plated onto Candida ID chromogenic media (BioMerieux). Blue colonies were reported as C. albicans; all other colonies (white and pink) were identified to species level using the Vitek YBC card (BioMerieux). In vitro susceptibility to amphotericin (AMB), fluconazole (FLU), itraconazole (ITZ), and voriconazole (VOR) was determined for approximately 40% of non-C. albicans yeasts using a standardised microdilution method.

RESULTS

Yeast was isolated from 1221 women (21%). Of these, C. albicans only was isolated from 1087 (89%) and yeasts other than C. albicans from 129 (11%) women. C. glabrata comprised 89 (69%) of the latter. Women in whom other yeasts were recovered were older than those with C. albicans (mean 43, versus 33 years, p <0.001). All isolates tested (n=53) were susceptible to AMB and VOR. Seven (24%) C. glabrata strains were susceptible to FLU with 21 (72%) testing susceptible-dose dependent.

CONCLUSION

Yeasts other than C. albicans are common vaginal isolates even in a primary care population. The species isolated are less susceptible to FLU than most C. albicans.

Partner violence among adolescents in opposite-sex romantic relationships: findings from the National Longitudinal Study of Adolescent Health

OBJECTIVES

This report examines (1) the prevalence of psychological and minor physical violence victimization in a nationally representative sample of adolescents and (2) associations between sociodemographic factors and victimization.

METHODS

Analyses are based on 7500 adolescents who reported exclusively heterosexual romantic relationships in the National Longitudinal Study of Adolescent Health. Items from the Conflict Tactics Scale were used to measure victimization. Associations between victimization patterns and sociodemographic characteristics were assessed with polytomous logistic regression.

RESULTS

One third of adolescents reported some type of victimization, and 12% reported physical violence victimization. Although most sociodemographic characteristics were significantly associated with victimization, patterns varied by sex and type of victimization.

CONCLUSIONS

Psychological and minor physical violence victimization is common in opposite-sex romantic relationships during adolescence. The sex-specific associations between sociodemographic characteristics and patterns of partner violence victimization underscore the importance of pursuing longitudinal, theory-driven investigations of the characteristics and developmental histories of both partners in a couple to advance understanding of this public health problem.

Focal small bowel perforation: an adverse effect of early postnatal dexamethasone therapy in extremely low birth weight infants

OBJECTIVE

We tested the hypothesis that early postnatal dexamethasone (EPD) increases the risk of focal small bowel perforation (FSBP) in extremely low birth weight (ELBW) infants.

STUDY DESIGN

The techniques of meta-analysis were applied to studies evaluating EPD, which we identified through a systematic literature search. Studies were included if they were randomized, placebo-controlled trials of EPD, enrolled infants with birth weights < or =1000 g, and reported FSBP as an outcome variable. The Breslow-Day test was used to assess for homogeneity and a summary odds ratio was calculated using the Mantel-Haenszel exact method.

RESULTS

Four studies, with a pooled sample of 1383 infants, were included in the primary analysis. The Breslow-Day test showed a p-value of 0.61, indicating homogeneity among the studies. FSBP was significantly higher in EPD treated infants [odds ratio 1.91, 95% confidence interval (CI) 1.21, 3.07; p=0.004].

CONCLUSION

EPD increases the risk of FSBP in ELBW infants.

Improved response with higher corticosteroid dose in children with acute lymphoblastic leukemia

PURPOSE

We investigated whether there was a dose-response relationship for the use of corticosteroids in childhood acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

Three hundred sixty-nine patients, ages 1 to 18 years with ALL, were randomly assigned to receive one of four different doses of corticosteroid (prednisolone 40 mg/m(2)/d or dexamethasone 6, 18, or 150 mg/m(2)/d) administered as a 3-day, single-drug window before initiation of standard, multidrug induction chemotherapy. Corticosteroid drug response was measured by reduction in bone marrow blast counts and absolute peripheral blast counts after 3 days. Glucocorticoid receptor (GCR) number and the effective concentration of dexamethasone resulting in a 50% reduction of leukemic cell viability in vitro (EC-50) were evaluated at days 0 and 3.

RESULTS

Increasing dexamethasone doses resulted in greater marrow blast response (P =.007), with a similar trend in peripheral-blood blast response. High-dose corticosteroid regimens (dexamethasone 18 or 150 mg/m(2)/d) elicited better responses than standard doses of dexamethasone or prednisone (bone marrow, P =.002; peripheral blasts, P =.05). Among patients treated with standard-dose corticosteroids, 38% with resistant (EC-50 > 10(-7)) peripheral blasts had a good response compared with 92% with sensitive (EC-50 < 10(-7)) peripheral blasts (P =.01). In contrast, there was no differential response according to EC-50 group after high-dose corticosteroids. Similarly, an association between response and GCR on peripheral-blood blasts was noted after standard-dose corticosteroid regimens but not after high-dose corticosteroid regimens.

CONCLUSION

Response of ALL to glucocorticoid therapy increased with dose. Higher-dose corticosteroid treatment abrogated the effect of relative drug insensitivity and of low GCR on peripheral blasts.

The effects of aging on AV nodal recovery properties

The purpose of this study was to assess the changes of AV nodal recovery properties with aging. Although in children and young adults it was found that there were age dependent changes in their AV nodal recovery properties, in the older population this information was not available. In 92 subjects (aged 16-92 years) without AV nodal disease or dual AV nodal pathway physiology, their AV nodal recovery curves were studied by delivering premature atrial extrastimuli coupled to basic atrial beats during cardiac electrophysiological study. Data were analyzed using linear regression and curve-fitting techniques. Patients were grouped by age, group I < 40 years (n = 33), group II 40-59 years (n = 26), and group III > 60 years (n = 33). The results showed that the AV nodal recovery curve did not change significantly in the aging process except that the AV nodal effective refractory period had a positive correlation with increasing age. The latter was significantly increased in group III when compared to group I or group II. For this parameter, when patients whose AV nodal refractory period was limited by the atrial refractory period were excluded, there was still a statistically significant increase in group III compared to group II (P < 0.05): group I (n = 27): 202+/-42 ms; group II (n = 17): 197+/-26 ms; and group III (n = 17): 224+/-46 ms. The results suggest that the AV nodal recovery curve remains unchanged once it reaches adulthood, with the exception that the nodal effective refractory period becomes slightly longer after age 60.

Central venous catheter-induced atrial ectopic tachycardia with reverse alternating Wenckebach periods

A centrally inserted venous catheter may cause atrial ectopic tachycardia. The association of atrial ectopic tachycardia with spontaneous reverse alternating Wenckebach periodicity has rarely been reported. We describe a 4-year-old boy with tetralogy of Fallot who developed atrial ectopic tachycardia with reverse alternating Wenckebach periods postoperatively after central venous catheter placement. All such episodes emerged from a 3:2 atrioventricular block, followed by runs of 2:1 atrioventricular block with progressive shortening of the conducted PR intervals. Normal sinus rhythm returned after the catheter was withdrawn to the superior vena cava. Reverse alternating Wenckebach periodicity may be a tachycardia-dependent physiologic phenomenon.

Initial low temperature setting in radiofrequency catheter ablation of Wolff-Parkinson-White syndrome

Previous studies have shown that with low temperature testing for RF ablation of arrhythmias, unnecessary irreversible myocardial lesions may be avoided. In children admitted for RF ablation from June 1996 to May 1999, we evaluated the method of an initial temperature setting of 50 degrees C for a maximum of 10 seconds. If accessory pathway block occurred, the temperature setting was immediately increased to 70 degrees C and continued for 45-120 seconds (group 1). If accessory pathway block did not occur after several attempts, subsequent attempts were made with initial settings at 70 degrees C-80 degrees C at the same or different sites (group 2). Eighty patients with Wolff-Parkinson-White syndrome (mean age 11 +/- 4 years) were treated using this method. Twelve patients were excluded for various reasons. Of the remaining 68 patients, 52 (76%) had successful block of the pathway at 50 degrees C; 16 patients demonstrated block only at the higher temperature setting of 70 degrees C-80 degrees C. There were no statistically significant differences between these two groups in terms of age, weight, and location of accessory pathways. Unsuccessful 50 degrees C test ablation attempts were 1.6 +/- 2.4 in group 1 and 3.1 +/- 2.9 in group 2 (P = 0.04). Total unsuccessful attempts were 1.6 +/- 2.4 in group 1 and 8.1 +/- 7.1 in group 2 (P = 0.001). The time from application of RF energy to the time of AP block in group 1 was not significantly different from group 2. In the majority of children, successful RF ablation can be achieved by using a temperature setting of 50 degrees C, then 70 degrees C. This will prevent unnecessary permanent injury at unsuccessful attempt sites.

The value of air plethysmography in predicting clinical outcome after surgical treatment of chronic venous insufficiency

PURPOSE

The role of air plethysmography (APG) as a predictor of clinical outcome after surgery in venous disease is yet to be defined. The purpose of this study was to investigate the value of APG in predicting clinical outcome after venous surgery for chronic venous insufficiency (CVI).

METHODS

Seventy-three extremities in 71 patients with Class 3 through 6 CVI were assessed preoperatively with CEAP (c linical, e tiologic, a natomic, p athophysiologic) criteria, standing reflux duplex ultrasound scan, and APG with measurements of preoperative venous filling index (VFI), venous volumes, ejection fraction, and residual volume fraction. After surgical treatment of the affected limbs, repeat APG studies were obtained within 6 weeks. Established venous reporting standards were used for follow-up to calculate clinical symptom scores (CSSs) in each patient.

RESULTS

Superficial venous reflux occurred alone in 24 limbs or in conjunction with perforator incompetence in 26 limbs. Deep and superficial reflux, with or without perforator incompetence, was found in 16 limbs, and seven limbs had isolated deep insufficiency. Follow-up was available in 60 of 71 patients (mean period, 44.3 months). Postoperative APG demonstrated significant hemodynamic changes after surgery as measured with VFI, venous volumes, ejection fraction, and residual volume fraction. Mean CSSs decreased from 7.35 +/- 0.56 preoperatively to 1.79 +/- 0.32 at late follow-up after surgery (P <.001). With the use of logistic regression, the parameter correlating most closely with clinical outcome was the VFI. A normal postoperative VFI (</= 2 mL/s) predicted a good clinical outcome (CSS </= 2) in follow-up patients, with a positive predictive value of 94%, a specificity of 89%, and a sensitivity of 70%.

CONCLUSIONS

Normalization of the VFI after venous surgery for CVI is predictive of a good clinical outcome. This APG measurement may be a useful parameter to predict adequacy of surgery in patients with venous insufficiency.

Phase II trial of 2-chlorodeoxyadenosine in patients with relapsed/refractory acute myeloid leukemia: a study of the Eastern Cooperative Oncology Group (ECOG), E5995

2-Chlorodeoxyadenosine (2-CdA) is a purine analog which has anti-leukemic activity in phase II trials in pediatric acute myeloid leukemia (AML) patients. An adult phase I trial suggested possible similar activity although neurotoxicity at higher doses was seen. We conducted a phase II trial of 2-CdA in patients with relapsed or refractory AML. 2-CdA was administered by continuous intravenous infusion at a dose of 17 mg/m(2) per day x5 days. Patients not achieving aplasia by day 21 were eligible for a second course of therapy. Fifteen patients (nine relapsed and six refractory AML) were enrolled including seven men and eight women with a median age of 60 years and median ECOG PS of 1. There were five deaths on study due to infections (two), AML (two), or hepatic failure (one). The 2-CdA was well tolerated without severe nausea, vomiting or stomatitis (all <grade 2). No severe neurologic complications related to 2-CdA were seen. Grade 4 myelosuppression occurred in nearly all patients with prolonged periods of pancytopenia and BM hypoplasia seen in most. There were no complete responses, though bone marrow aplasia was achieved in eight patients. 2-CdA as a single agent, in the doses used in this study, is ineffective therapy for relapsed or refractory AML.

Phase II trail of didemnin B in previously treated non-Hodgkin's lymphoma: an Eastern Cooperative Oncology Group (ECOG) Study

Patients with non-Hodgkin's lymphoma (NHL) who fail initial therapy have a poor prognosis. We conducted a phase II study to determine the efficacy and toxicity of didemnin B, a non-myelosuppressive marine compound, in patients with NHL who relapsed or progressed after receiving one or two previous chemotherapy regimens. Fifty-one eligible patients were registered on this phase II study. Twenty-nine patients had intermediate or high grade (IG/HG) disease and 22 patients had low grade (LG) disease. Twenty-five patients received didemnin B at a dose of 6.3 mg/m2 and the remainder received 5.6 mg/m2, administered intravenously every 28 days. The patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 and biopsy-proven relapsed disease. Objective responses were observed in two (7%) patients (one complete remission [CR] and one partial remission [PR]) with IG/HG disease and five (23%) patients (one CR and four PR) with LG disease. Patients with IG/HG disease had a median time to treatment failure (TTF) of 1.6 months and a median survival of 8.0 months. In contrast, the group with LG disease had a median TTF of 4.6 months and a median survival of 2.7 years. There were five grade V, 12 grade IV, and 57 grade III toxicities. Didemnin B appears to have modest activity in low grade NHL. However, the drug has considerable toxicity in this population of patients.

Radiofrequency catheter ablation of tachycardia in children with and without congenital heart disease: indications and limitations

From 1993 to 1998, a total of 100 consecutive pediatric patients with tachycardia (45 male and 55 female, aged 1 year 10 months to 17 years, 11+/-4 year) who underwent electrophysiological study were reviewed. Eleven of them were younger than 5 years. Two had tachycardia-related cerebrovascular accident. Congenital heart disease was found in 12 patients. After propofol anesthesia, the clinical tachycardia could not be induced in three (two atrial tachycardia and one AV nodal re-entrant tachycardia) and became nonsustained in five (atrial tachycardia). Mechanical ablation occurred in three and two had subsequent recurrences. Among the 85 cases who received radiofrequency ablation, the overall final success rate of RF ablation for all diagnoses was 94% with a diagnosis-specific success rate ranging from 100 to 57%. Tachycardia cardiomyopathy was noted in four (three atrial tachycardia and one junctional ectopic tachycardia) and all regressed after successful ablation. Success in two patients with left posterioseptal accessory pathway could only be achieved by delivering the energy at the middle cardiac vein. Two patients with right atrial isomerism had an 'AV nodal-to-AV nodal tachycardia' which was eliminated by ablation. Total recurrence rate was 13% but final success was achieved in all during re-study except the three patients who refused re-intervention. The atrial tachycardia developed in postoperative congenital heart disease was associated with the lowest success rate (57%) and highest recurrence rate (25%). Procedure-related complications occurred in four; two with transient brachial palsy, one with first-degree AV block and one with blood loss requiring blood transfusion. In conclusion, the experience of this single center confirmed the efficacy and safety of radiofrequency catheter ablation in treating pediatric arrhythmias, but the limitations in postoperative arrhythmias and the effects of propofol on tachycardia induction (especially the atrial tachycardia) need to be improved.

Late events in pediatric patients with Ewing sarcoma/primitive neuroectodermal tumor of bone: the Dana-Farber Cancer Institute/Children's Hospital experience

The outcome for 82 pediatric patients with Ewing sarcoma (ES) and primitive neuroectodermal tumor (PNET) of bone is reported; the patients were treated at the Dana-Farber Cancer Institute (DFCI) and Children's Hospital (CH) in Boston, MA (USA) from 1971-1988. The charts of all patients with ES/PNET of bone treated during this period were reviewed for disease status, therapy, sites of relapse, information on second malignancies, and survival status. Eighty-two patients with ES/PNET of bone treated at DFCI/CH were identified. The 10-year event-free survival (EFS) rates were 12% (95% confidence interval [CI] 0, 27%) and 38% (95% CI 26, 51%) for patients with and without metastases, respectively (P = 0.002); the overall survival (OS) rates were 17% (95% CI 1, 33%) and 48% (95% CI 35, 61%) for patients with and without metastases (P = 0.001). Median follow-up for surviving patients is 10.2 years. Primary site in the pelvis also was associated with a poor outcome for patients with no metastatic disease (P = 0.006 OS, P = 0.03 EFS). Thirty-one patients survived in first remission at least 5 years from diagnosis, and of these, five experienced relapse of original disease, and five experienced secondary malignancies. Pediatric patients treated for ES/PNET of bone remain at risk for life-threatening events into the second decade of follow-up. After 5 years, the risk of second malignant neoplasm is at least as high as the risk of late relapse. Prolonged follow-up of patients with ES and PNET of bone is indicated.

Adherence with referrals for outpatient follow-up from a VA psychiatric emergency room

This study identifies patient characteristics associated with adherence to outpatient mental health treatment referrals from a VA psychiatric emergency department. Attendance of outpatient appointments was monitored for 12 weeks following emergency department visits (N = 241). Overall attendance of the first appointments was 53%, ranging from 34% of the homeless, to 82% of patients with alcoholism in remission. Characteristics associated with initial adherence included having a place to live and the diagnosis of depression. At twelve weeks, the diagnosis of substance abuse was associated with worse ongoing adherence. The results underscore the need to develop interventions targeting patients at highest risk of poor adherence.

Paired ventricular pacing: an alternative therapy for postoperative junctional ectopic tachycardia in congenital heart disease

Junctional ectopic tachycardia (JET) is one of the most life-threatening postoperative arrhythmias in children with congenital heart disease, and medical management is difficult. Paired ventricular pacing (PVP) may provide a safe alternative mode of management. We evaluated the safety and efficacy of PVP for the management of postoperative JET in patients with congenital heart disease. A retrospective collection of data was done from 1981-1995. PVP was successfully tried in five postoperative patients (age range: 37 days to 22 years, median: 10 months). Onset of JET was 3-60 hours (mean +/- SD, 19 +/- 23 hours) postoperatively. The maximal JET rate was 261 +/- 39 beats/min. PVP was used as the first line of management in three patients and was successful in all patients. It resulted in an instantaneous increase in blood pressure from 66 +/- 9 to 94 +/- 15 mmHg (42% increase) and was required for 12 +/- 14 hours (range 2-36 hours). No complications were noted. Therefore, in our experience, this is a safe alternative modality for the control of postoperative JET.

Induction failure in acute lymphoblastic leukemia of childhood

BACKGROUND

Although it is widely accepted that failure to achieve complete remission (CR) portends a poor prognosis in childhood acute lymphoblastic leukemia (ALL), there is variability in the precise definition of induction failure and, to the authors' knowledge, few published data exist regarding the outcome of patients who are slow to achieve CR.

METHODS

Between 1987-1995, 774 children with ALL were treated on 2 consecutive protocols and were evaluable to assess the time required to attain CR. The authors compared presenting characteristics and outcomes of patients based on their remission status after 1 month of induction chemotherapy: CR (n = 656), protracted hypoplasia (low peripheral blood counts and/or hypocellular marrow) (n = 95), and persistent leukemia (M2 or M3 bone marrow and/or evidence of extramedullary leukemia) (n = 23). The median follow-up was 5.2 years.

RESULTS

Presenting features that predicted persistent leukemia included a leukocyte count > 100,000/mm3 and T-cell phenotype. Approximately 91% of patients with persistent leukemia and 100% with protracted hypoplasia eventually achieved CR. The 5-year event free survival (EFS) (95% confidence intervals [95% CI] in parentheses) for patients with persistent leukemia after 1 month was 16% (95% CI, 0%, 31%), which was significantly worse (P < 0.001) than that for those who achieved CR within 1 month (5-year EFS, 82%; 95% CI, 79%, 86%) and that for those with protracted hypoplasia (5-year EFS, 79%; 95% CI, 70%, 87%). For patients with persistent leukemia, there was no significant difference in survival based on bone marrow status (M2 or M3) after 1 month or on the number of induction cycles received before achieving CR.

CONCLUSIONS

Patients with persistent leukemia at the end of 1 month of therapy have a dismal prognosis, regardless of when they subsequently achieve CR. More intensive and/or novel therapies should be considered for this subset of patients.

Controlled ventilation enhances catheter stability during radiofrequency ablation

Variations in the amplitude of the atrial and ventricular depolarization waves of the intracardiac electrogram occur during different phases of respiration. Therefore, we tested whether controlled ventilation would reduce ablation attempts and increase the rate of success in patients undergoing radiofrequency ablation with general anesthesia. Thirty-eight children were divided into two groups: (1) controlled and (2) noncontrolled or cyclic ventilation. In the controlled ventilation group, the mapping electrogram was recorded during sustained inspiration, sustained expiration, and cyclic ventilation. Ablation was done in the phase of ventilation that had the least variability in atrial and ventricular amplitudes. Seventeen patients in the controlled ventilation group had tracings adequate for review. In eight patients, ablation was done during sustained inspiration with the percentage change of atrial and ventricular amplitudes (15% +/- 16% and 13% +/- 16%, respectively) being < that during sustained expiration (38% +/- 27%, P = 0.04 and 20% +/- 21%) or during cyclic ventilation (57% +/- 27%, P < 0.01 and 54% +/- 26%, P = 0.003). In nine patients, ablation was done during sustained expiration with the percentage change of atrial and ventricular amplitudes (5% +/- 5% and 5% +/- 2%) being less than that during sustained inspiration (21% +/- 14%, P = 0.01 and 11% +/- 6%, P = 0.01) or during cyclic ventilation (68% +/- 23%, P < 0.001 and 48 +/- 26%, P = 0.001). We achieved success with each patient in both groups, but the number of ablation attempts were less in the controlled ventilation group 1 (3 +/- 2), as compared to the cyclic ventilation group 2 (8 +/- 8; P < 0.02). We concluded that controlled ventilation reduced the number of ablation attempts and facilitated the ablation procedure.

Incidence of TEL/AML1 fusion in children with relapsed acute lymphoblastic leukemia

The TEL/AML1 fusion associated with t(12;21)(p13;q22) is the most common gene rearrangement in childhood leukemia, occurring in approximately 25% of pediatric acute lymphoblastic leukemia (ALL), and is associated with a favorable prognosis. For example, a cohort of pediatric patients with ALL retrospectively analyzed for the TEL/AML1 fusion treated on Dana-Farber Cancer Institute (DFCI) ALL Consortium protocols between 1980 to 1991 demonstrated a 100% relapse-free survival in TEL/AML1-positive patients with a median of 8.3 years of follow-up. However, two recent studies analyzing pediatric patients with relapsed ALL have reported the same incidence of the TEL/AML1 rearrangement as in patients with newly diagnosed ALL, suggesting that TEL/AML1 positivity is not a favorable prognostic indicator. To clarify this apparent discrepancy, 48 pediatric patients treated on Dana-Farber Cancer Institute (DFCI) protocols with ALL at first or second relapse were tested for TEL/AML1 using reverse transcriptase-polymerase chain reaction (RT-PCR). The TEL/AML1 fusion was identified in only 1 of 32 analyzable relapsed ALL patients, in concordance with our previous reports of improved disease-free survival in TEL/AML1-positive patients. The low frequency of TEL/AML1-positive patients at relapse is significantly different than that reported in other studies. Although there are several potential explanations for the observed differences in TEL/AML1-positive patients at relapse, it is plausible that relapse-free survival in TEL/AML1-positive patients may be changed with different therapeutic approaches. Taken together, these results support the need for prospective analysis of prognosis in TEL/AML1-positive patients.

Comparison of axillary and infrared tympanic membrane thermometry in a pediatric oncology outpatient setting

The purpose of this study was to determine whether infrared tympanic membrane thermometry can replace mercury-in-glass temperatures as an assessment tool for detecting fevers earlier and more reliably in a pediatric oncology outpatient setting. A total of 313 patient visits had infrared tympanic temperatures (obtained by using the LighTouch LTX Pedi-Q thermometer (Exergen; Watertown, MA) and axillary temperatures taken simultaneously (obtained by using mercury-in-glass thermometers). Those patients with a normal axillary temperature and an elevated tympanic measurement of 38 degrees C or higher had a follow-up axillary temperature conducted that evening to determine whether an elevated tympanic temperature predicted on coming fever or infection. The mean tympanic temperature was 37.5 degrees C and the mean axillary temperature was 36.8 degrees C, a difference of 0.7 degree C (P = .0001). Sixty-two (20%) patients had discrepant temperatures with a febrile tympanic and normal axillary measurement. Three (5%) of these patients were febrile at their follow-up axillary reading. Tympanic thermometry resulted in a significantly higher temperature reading than the axillary method. Elevated tympanic temperatures were not predictive of oncoming fever or infection. Fevers were not missed when using the tympanic method. To prevent unnecessary medical intervention, it is recommended that mercury-in-glass thermometers verify elevated tympanic temperatures.

Supraventricular tachycardia in patients with right atrial isomerism

OBJECTIVES

To clarify the prevalence and mechanism of supraventricular tachycardia in patients with right atrial isomerism.

BACKGROUND

Paired SA and dual atrioventricular (AV) nodes have been described in patients with right atrial isomerism. However, the clinical significance remains unclear.

METHODS

From 1987 to 1996, a total of 101 patients (61 male, 40 female) and four fetuses were identified with right atrial isomerism. The diagnosis of supraventricular tachycardia exclude the tachycardia with prolonged QRS duration or AV dissociation, and primary atrial tachycardia.

RESULTS

The median follow-up duration was 38 months (range 0.2-270 months). Supraventricular tachycardia was documented in 25 patients (24.8%) and one fetus (25%) (onset age ranged from prenatal to 14 years old; median 4 years old). Actuarial Kaplan-Meier analysis revealed that the probability of being free from tachycardia was 67% and 50% at 6 and 10 years of age, respectively. These tachycardias could be converted by vagal maneuvers in one, verapamil in seven, propranolol in four, digoxin in two, procainamide in one, and rapid pacing in five. Spontaneous conversion was noted in six (including the fetus). Seven cases had received electrophysiological studies. Reciprocating AV tachycardia could be induced in five and echo beats in one. The tachycardia in three patients was documented as incorporating a posterior AV node (antegrade) and an anterior or a lateral AV node (retrograde). Two of them received radiofrequency ablation. Successful ablation in both was obtained by delivering energy during tachycardia, aimed at the earliest retrograde atrial activity and accompanied by junctional ectopic rhythm. The patient with echo beats developed tachycardia soon after operation.

CONCLUSIONS

Supraventricular tachycardia is common in patients with right atrial isomerism and can occur during the prenatal stage. Drugs to slow conduction through the AV node may help to terminate the tachycardia. Radiofrequency ablation is a safe and effective treatment alternative to eliminate tachycardia.

Effects of blocked atrial beats on the atrioventricular nodal recovery property: facilitation or depression?

INTRODUCTION

Blocked atrial beats (A(B)) usually have concealed AV nodal penetration, which can change the nodal conduction time (AH) of a subsequent beat. However, without an output marker it is difficult to assess their effect on the node. In this report we used all possible parameters as nodal resting time after A(B) and plotted them against the AH of testing beats to study their effects on the node.

METHODS AND RESULTS

Atrial extrastimulation studies were done in 21 patients in whom one blocked atrial beat (A(2B)) was observed. Nodal recovery curves were obtained for basic pacing (A1), after a conducted premature beat (A2), and after A(2B). In six patients there were 2 to 3 consecutively blocked beats (A(nB)) and recovery curves were constructed after each A(nB). Nodal recovery curves were plotted with AH of the testing beat against different nodal resting parameters and fitted to a single exponential equation. We found contradicting phenomena when using different formats. (1) For recovery curves of A(2B), there was a rightward shift from that of the basic curve when using H1A3 or A1A3 as the gauge (depression phenomenon). On the contrary, there was a leftward shift of the curves when using A(2B)A3 (facilitating phenomenon). (2) For recovery curves after multiple blocked beats there was a marked rightward shift of all curves except A(n-1)(B)An-curves, which were all leftward shifted.

CONCLUSION

Because these contradicting phenomena were dictated by the presenting formats, the terms "depression" and "facilitation" cannot be considered intrinsic AV nodal properties outside of the strict context of the pacing protocol and the format of data presentation.

MOPP/ABV hybrid chemotherapy for advanced Hodgkin's disease significantly improves failure-free and overall survival: the 8-year results of the intergroup trial

PURPOSE

To compare the efficacy of sequential mechlorethamine, vincristine, procarbazine, and prednisone (MOPP) followed by doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) versus the MOPP/ABV hybrid regimen in advanced-stage Hodgkin's disease.

PATIENTS AND METHODS

A total of 737 patients with previously untreated stages III2A, IIIB, IVA, or IVB Hodgkin's disease and patients in first relapse after radiotherapy were prospectively randomized to sequential MOPP-ABV or MOPP/ABV hybrid. Of 691 eligible patients, 344 received the sequential regimen and 347 received the hybrid.

RESULTS

The overall response rate was 95%, with complete responses (CRs) in 79%: 83% on the MOPP/ABV hybrid and 75% on the sequential MOPP-ABVD arm (P = .02). With a median follow-up time of 7.3 years, the 8-year failure-free survival (FFS) rates were 64% for MOPP/ABV hybrid and 54% far sequential MOPP-ABVD (P = .01; 0.69 relative risk of failure, comparing MOPP/ABV hybrid v MOPP-ABVD). The 8-year overall survival rate was significantly better for the MOPP/ABV hybrid (79%) as compared with sequential MOPP-ABVD (71%) (P = .02; relative risk, 0.65). MOPP/ABV hybrid had significantly more life-threatening or fatal neutropenia and pulmonary toxicity than the sequential MOPP-ABVD arm, which was associated with significantly greater thrombocytopenia. Nine cases of acute myelogenous leukemia or myelodysplasia were reported on the sequential regimen as compared with only one on the hybrid (P = .01).

CONCLUSION

MOPP/ABV hybrid chemotherapy was significantly more effective than sequential MOPP-ABVD. FFS and overall survival were significantly improved on the hybrid arm, which was also associated with a lower incidence of acute leukemia or myelodysplasia.

Long-term survival in acute myeloid leukemia: the Eastern Cooperative Oncology Group experience

BACKGROUND

The data base of the Eastern Cooperative Oncology Group (ECOG) provides access to data on a large adult patient population drawn from more than 25 major university institutions and hundreds of participating hospitals. Extensive medical files are maintained at the ECOG Coordinating Center and are updated regularly.

METHODS

Data on 1414 eligible patients with acute myeloid leukemia (AML), treated on 6 ECOG protocols during the period 1976-1994, were reviewed to determine the number of long-term survivors (LTS) and to identify factors that predicted LTS. Disease free survival and factors impacting quality of life were examined as well.

RESULTS

Of the 1414 patients, 274 survived for > or = 3 years and were considered LTS. A logistic regression analysis revealed that factors predicting LTS included age < 55 years, female gender, treatment between 1985 and 1990, white blood cell count < 10,000 cells/mm3, and hemoglobin > 10 g/dL. Disease free survival improved with escalating intensity of therapy. Quality-of-life data showed that infections were fairly common. Significant graft-versus-host disease occurred in 6 of 40 patients who received allogeneic bone marrow transplantation and contributed to the deaths of 4 individuals. Information on employment, insurance, social or marital difficulties, and psychosocial issues was more difficult to obtain.

CONCLUSIONS

Prognosis in AML is a complex interaction involving the cellular origin of the malignant clone, morphology, and evolving therapeutic strategies. The most recent ECOG studies incorporate these variables and should provide additional insights into factors affecting LTS in patients with AML.

Developmental changes of atrioventricular nodal recovery properties

Atrioventricular (AV) nodal recovery properties can be studied by a periodic premature stimulation protocol performed at a slow basic rate. Developmental aspects of these properties have not been determined. The purpose of this study was to determine the developmental changes of AV nodal recovery properties. Forty-three children and young adults (male:female ratio 25:18) without AV nodal disease (aged 3.3 to 21.9 years) were studied by delivering premature atrial extrastimuli coupled to basic driven atrial beats. The individual recovery curve was fitted to the equation: A2H2 = A0H0 + exp(alpha -H1A2/tau) for H1A2 > or =theta, where A0H0 is the minimum AH interval, H1A2 is any recovery interval that exceeds the nodal effective refractory period, A2H2 is the corresponding nodal conduction time at any given H1A2, alpha is a constant, tau is the recovery time constant, and theta is the nodal effective refractory period. We found that: (1) A0H0 and alpha constant did not change significantly with age; (2) both tau (r = 0.324; p <0.05) and theta (r = 0.401; p <0.05) had a positive correlation with age; and (3) the maximum change in A2H2 with a 10-ms decrement in H1A2 was 32 ms and did not change significantly with age. Our results suggest that AV nodal recovery properties are age-dependent and both the recovery time constant and effective refractory period lengthen with age.

Radiofrequency catheter ablation of a verapamil-sensitive ventricular tachycardia

A 14-year-old girl with palpitations was found to have idiopathic ventricular tachycardia of right bundle block morphology and superior axis. She was converted by intravenous verapamil but was not responsive to oral verapamil therapy. She was successfully treated by radiofrequency catheter ablation.

Similar time-dependent recovery property of fast and slow atrioventricular nodal pathways

The purpose of this study was to determine whether fast and slow atrioventricular (AV) nodal pathways have the same recovery property. AV nodal recovery property is studied by delivering atrial extrastimuli coupled to atrial beats and plotting nodal coupling intervals against nodal conduction time. In patients with dual pathways the resultant curves will include a fast to fast (F-F) and a fast to slow (F-S) pathway coupled curves. Although fast pathway recovery property can be represented by the former, slow pathway recovery property requires further assessment by studying slow to slow (S-S) pathways coupled curve. In 9 patients with dual pathways F-F, F-S, S-F, and S-S curves were obtained by pacing protocols. In 8 patients (control) without dual pathways, F-F curve and atrial extrastimuli coupled to a preceding slowly conducted fast pathway beat (also designated as S-F curve) were obtained. (1) The S-S curve had a similar time constant as the F-F curve. (2) Although the S-S curve was markedly shifted upward and leftward from the F-F curve, the degree of leftward and upward shifts of the S-S curve from the F-F curve were both close to the difference of the basic fast and slow pathway conduction time (a constant). (3) Although the effective refractory period of the fast pathway in dual pathway patients was longer than that of the control patients, the slow pathway effective refractory period when corrected was close to that of fast pathway in control patients. These results suggest that the fast and slow AV nodal pathways have a similar time-dependent recovery property.

Follow-up of coil occlusion of patent ductus arteriosus

OBJECTIVE

We sought to determine the prevalence and fate of residual ductal shunting following coil occlusion of patent ductus arteriosus.

BACKGROUND

Although transcatheter coil occlusion of patent ductus arteriosus has gained popularity, few follow-up data have been reported.

METHODS

A review of 75 patients who underwent coil occlusion was performed. Residual shunting was investigated by Doppler echocardiography in follow-up. Angiograms were reviewed to obtain minimal ductal diameter and ductal angiographic type.

RESULTS

Residual shunts were found in 31 patients (41%) on the day of the procedure, and of these, spontaneous closure was noted in 17 (55%) at 2 weeks to 20 months of follow-up. Of the 75 patients studied, 5 (7%) required a second coil procedure, and 10 (13%) remained with persistent residual shunts at most recent follow-up. Actuarial analysis estimated a 6 +/- 5% prevalence of residual shunts 20 months after a single coil procedure and 3 +/- 3% after all coil procedures. Minimal ductal diameter was associated with immediate complete ductal occlusion by a single coil. These patients had significantly smaller (p = 0.003) minimal ductal diameters (1.2 +/- 0.7 mm) than those who required two coils during their initial procedure to achieve immediate occlusion (1.9 +/- 0.7 mm), those who required a second coil procedure (2.0 +/- 0.9 mm), those who had spontaneous closure of residual shunts (1.9 +/- 0.7 mm) and those with persistent residual shunts (2.0 +/- 0.9 mm). No association was identified between ductal angiographic type and outcome of coil occlusion. No late adverse clinical events of coil occlusion or evidence of recanalization was found.

CONCLUSIONS

Small residual shunts are common after coil embolization of patent ductus arteriosus, but most close spontaneously. Actuarial analysis estimates complete closure in 94% at 20 months, and reintervention was required in only 7% of patients.

Usefulness of tilt table test with normal saline infusion in management of neurocardiac syncope in children

Head-up tilt test has been useful in evaluating children with neurocardiac syncope. In this study patients with positive baseline and isoproterenol tests had repeat tilt testing done after normal saline infusion. If the symptoms persisted, the test was then repeated with phenylephrine infusion. Of the 101 patients studied, 58 (57%) had a positive tilt sign. Normal saline infusion was given to 53 patients. Three patients were excluded because of structural heart disease. Fifty patients (aged 14 +/- 4 years) comprised the study group. Forty-two (84%) of 50 patients had a negative repeat tilt sign after normal saline infusion, and these patients were treated with 0.5 to 1 gm of salt three times a day and/or fludrocortisone (20 patients). Of the 8 (16%) patients who did not respond to normal saline infusion, 5 had negative results when given phenylephrine and were treated with pseudoephedrine. Follow-up data on 42 patients (range 4 to 40 months, median 18 months) showed that all 35 patients who responded to normal saline were either asymptomatic or had improved. Two patients were successfully treated with pseudoephedrine; however, two patients in this group required pacemaker therapy. We conclude that (1) normal saline infusion mitigates the hemodynamic effects of neurocardiac syncope, (2) high-salt diet treatment in these patients was economical and effective, and (3) failure to respond to normal saline test may indicate a less favorable prognosis.

The effect of early discharge and other factors on readmission rates of newborns

OBJECTIVE

To assess the relationship between early discharge, breast feeding, and other factors on hospital readmission of newborns.

DESIGN

Retrospective record review.

SETTING

An urban, private community hospital.

PATIENTS

All newborns born over a 1-year period who were readmitted to the hospital within the first 3 weeks of life (n=117). The control group consisted of a systematic sampling of newborns born over the same period who were not readmitted (n=147).

RESULTS

Early discharge, defined as discharge when younger than 24, 36, or 48 hours of age, does not seem to contribute to readmission. However, newborns whose initial stay was longer than 72 hours were at significantly lower risk for readmission (P=.02, chi(2)). Factors in the initial hospitalization associated with readmission included vaginal delivery and length of stay less than 72 hours (difference, 12 percentage points; 95% confidence interval [CI], 4% to 20%; P=.005), need for performance of a complete blood count (CBC) (difference, 16 percentage points; CI 6% to 26%; P=.002), presence of jaundice (difference, 17 percentage points; CI, 5% to 29% P=.005), and gestational age 37 weeks or less (difference, 10 percentage points; CI, 2% to 18%; P=.02), discharge weight less than 3 kg (difference, 11 percentage points; CI, 0 to 22%; P=.05). However, almost all newborns delivered vaginally were discharged within less than 72 hours, so our ability to comment on the independent effect of delivery mode on readmission is limited. A trend toward significance was noted between breast-feeding and readmission (difference, 9 percentage points; CI, 0% to 18%; P=.07). However, when only vaginal deliveries were considered, this association was statistically significant (difference, 13 percentage points; CI, 4% to 22%; P=.02). A significant association was noted between breast-feeding and jaundice or dehydration. Of babies admitted with jaundice or dehydration, 94% were breast-fed, compared with 67% of babies admitted with neither jaundice nor dehydration (difference, 27 percentage points; CI, 13% to 41%; P<.001).

CONCLUSIONS

These findings strongly suggest that early discharge (at younger than 24, 36, or 48 hours of age) from the hospital is not associated with hospital readmission within the first 3 weeks of life. Factors associated with readmission included breast-feeding, vaginal delivery and length of stay less than 72 hours, jaundice or need for a CBC, gestational age of 37 weeks or less, and discharge weight less than 3 kg.

Influence of sample number and biopsy site on the histologic diagnosis of diffuse lung disease

BACKGROUND

Although open biopsy is considered the optimal method for obtaining lung tissue for the diagnosis of diffuse infiltrative pulmonary disorders, there are no universally established guidelines concerning biopsy site selection and the ideal number of tissue samples. Relatively few investigations have been devoted to the influence exerted by the site and number of biopsy samples on the histologic diagnosis.

METHODS

Seventy-seven open biopsy samples obtained from different lobes of 28 patients with idiopathic pulmonary fibrosis were analyzed. The histopathologic features were evaluated semiquantitatively and the results from each sample compared with those of the other samples obtained from each patient.

RESULTS

Statistically significant differences in histopathologic features were not observed between samples.

CONCLUSIONS

A single generous (2 cm or greater diameter) sample, obtained from a representative region of the radiographically most involved lobe, will suffice for diagnostic and evaluation purposes.

Electrophysiological basis for antiarrhythmic efficacy, positive inotropy and low proarrhythmic potential of (-)-caryachine

1. (-)-Caryachine, isolated from the plant (Cryptocarya chinensis), increased the contractility of atrial and right ventricular strips and significantly suppressed the reperfusion arrhythmias in adult rabbit heart (ED50 = 1.27 microM). 2. Data obtained by the whole-cell voltage clamp technique has shown that (-)-caryachine causes a negative shift of the steady-state Na channel inactivation and a slower rate of recovery from inactivation. The maximal Na current amplitude decreased to 67 +/- 7%, 29 +/- 8% and 12 +/- 5% after 0.5, 1.5 and 4.5 microM (-)-caryachine, respectively. 3. This agent also had effects on the time- and voltage-dependent K currents. (-)-Caryachine markedly suppressed the 4-AP-sensitive transient outward current (I10). However, it produced very little voltage-dependent shift in inactivation. After 0.5, 1.5 and 4.5 microM of the compound, the respective value of I10 elicited at +60 mV was 80 +/- 7%, 45 +/- 8% and 15 +/- 3%. At higher concentrations, the inward rectifier K current (IK1) was also inhibited but to a much smaller extent. Its slope conductance after 0.5, 1.5 and 4.5 microM (-)-caryachine was reduced to 71 +/- 9%, 51 +/- 12% and 42 +/- 11%, respectively. The outward hump of inward rectification was not changed. 4. In contrast, the L-type Ca current was not significantly changed by (-)-caryachine. 5. Electrophysiological studies in perfused whole heart preparations revealed that (-)-caryachine increased the intra-atrial conduction interval and also prolonged the atrial refractory period. No proarrhythmic effects were induced during the infusion of this compound (up to 13.5 microM). 6. We conclude that (-)-caryachine predominantly blocks the Na and I10 currents. These changes alter the electrophysiological properties of the heart and terminate the induced ventricular arrhythmias. The relatively selective I10 inhibition, safety margin of Ik1 suppression and lack of effect on Ica-L will provide an opportunity to develop an effective antiarrhythmic agent with positive inotropy as well as low proarrhythmic potential.

Electrophysiological properties of dual atrioventricular nodes in patients with right atrial isomerism

There are reports that in right atrial isomerism the conduction system has paired sinus nodes and paired atrioventricular nodes. Electrophysiological studies were performed in two patients with right atrial isomerism. One patient had a delta wave on the surface electrocardiogram without tachycardia attacks. The other, who did not have manifest pre-excitation, had recurrent narrow QRS tachycardia. Electrophysiological studies suggested the presence of dual atrioventricular nodes. Only unidirectional atrioventricular or ventriculoatrial conduction was demonstrated for these dual atrioventricular nodes even after infusion of isoprenaline. It is suggested that unidirectional conduction may be a common property of the dual atrioventricular nodes in right atrial isomerism and that the absence of retrograde ventriculoatrial conduction protects the patients against tachycardia.

Radiofrequency catheter ablation of supraventricular tachycardias in pediatric patients

Supraventricular tachycardia (SVT) is the most common cardiac arrhythmia in children. Atrioventricular (AV) reciprocating tachycardia utilizing an accessory pathway and AV nodal reentrant tachycardia (AVNRT) constitute a majority of SVTs. Radiofrequency energy ablation has recently become the treatment of choice in adults. Initial experience in pediatric patients in this Institute is reported in this study. Six consecutive patients (aged 5-22 years, mean age 13 years; 3 boys, 3 girls) with narrow-QRS SVT were studied from July to October in 1993. They had experienced symptomatic SVT for a mean period of five years (ranged from 1 to 15 years). Anti-arrhythmic agents, including beta-antagonists and calcium channel blockers, were unable to satisfactorily suppress these SVTs. Four of the six patients were shown to have a left-sided concealed accessory connection as the retrograde limb of the reentrant circuit. After identification of the earliest retrograde activation site, a steerable 7F catheter with a 4-mm-long electrode at the distal tip was placed within the left ventricle and positioned against the atrio-ventricular annulus. Another two patients were proved to have AVNRT. The ablation catheter was placed at the posterior/inferior aspect of the tricuspid annulus and guided by putative slow potential. Radiofrequency current was delivered at a power from 15 to 25W for four to six times with a mean duration of 40 seconds in patients with AV reciprocating tachycardia, and a single time in those with AVNRT. All six SVTs were successfully ablated. No complication was noted in any patient. Follow-up for three to seven months has indicated no recurrence of SVT.(ABSTRACT TRUNCATED AT 250 WORDS)

Localized hypothermia influences assessment of recovery from vecuronium neuromuscular blockade

The purpose of this study was to determine the extent to which localized hypothermia of a monitored extremity alters the assessment of recovery from vecuronium-induced neuromuscular blockade. Bilateral integrated evoked electromyographic (IEMG) responses were measured in the ulner distribution of 14 anaesthetized patients who had differing upper extremity temperatures as measured at the adductor pollicis to determine whether localized hypothermia alters the clinical assessment of spontaneous recovery from vecuronium-induced neuromuscular blockade. All patients received general anaesthesia with thiopentone, N2O/O2 and opioid; 11/14 patients received isoflurane for blood pressure control. Bilateral adductor pollicis, oesophageal and ambient temperatures, and IEMG evoked response (t1) expressed as percent unparalyzed control were recorded during the anaesthetic. The difference in evoked response between the warmer and the colder upper extremity was calculated at 25%, 50% and 75% spontaneous recovery from neuromuscular blockade in the warm extremity. Differences in temperature between extremities ranged from 0.2-11 degrees C. The difference in IEMG-evoked response between extremities was proportional to the difference in temperature, and there was a direct correlation (r = 0.78) between IEMG response and extremity temperature; IEMG response was absent when extremity temperature was less than 25 degrees C. We concluded that localized hypothermia in the monitored extremity decreases the IEMG-evoked response to vecuronium neuromuscular blockade; the greater the temperature decrease, the less the evoked response.(ABSTRACT TRUNCATED AT 250 WORDS)

The electrophysiological effects of antiarrhythmic potential of a secoaporphine, N-allylsecoboldine

1. A satisfactory antiarrhythmic potential of N-allylsecoboldine, a synthetic derivative of secoaporphine, has been documented. Its effects on the ionic currents of cardiac myocytes and the influence on the electrophysiological properties of the conduction system in Langendorff perfused hearts were investigated. 2. Ionic currents were studied by voltage clamp in the whole cell configuration. N-allylsecoboldine blocked the Na channel with a leftward-shift of its half voltage-dependent inactivation and a slower rate of recovery from the inactivation state. Similarly, calcium inward currents were inhibited but to a much smaller extent. 3. N-allylsecoboldine inhibited the 4-AP-sensitive transient outward K current. Currents through the K1 channels were also reduced. 4. As compared with quinidine, N-allylsecoboldine caused a comparable degree of block on Na and K1 currents but blocked to a lesser extent the Ca and Ito currents. 5. In the perfused whole-heart model, N-allylsecoboldine caused a dose-dependent prolongation in sinoatrial, atrioventricular and His-Purkinje system conduction intervals and prolonged the effective refractory periods of the atrium, AV node, His-Purkinje system and ventricle. However, the basic cycle length was not significantly affected. As compared to quinidine, N-allylsecoboldine exerted less pronounced effects on both the basic cycle length and the atrial and AV nodal refractory periods. 6. We conclude that N-allylsecoboldine predominantly blocks Na and K1 channels and in similar concentrations partly blocks Ca channels and Ito. These effects result in a modification of the electrophysiological properties of the conduction system which provides a satisfactory therapeutic potential for the treatment of cardiac arrhythmias.

The electrophysiological effects of dicentrine on the conduction system of rabbit heart

1. The electrophysiological effects of dicentrine, an aporphine alkaloid isolated from the root of Lindera megaphylla, were examined in the Langendorff perfused rabbit heart and rabbit isolated cardiac cells. 2. Standard electrophysiological characters were measured in the Langendorff perfused rabbit heart (control study) and after 5 min exposure to 1, 3 and 9 microM of dicentrine and during the subsequent recovery phase sequentially (n = 7). The same study protocols were performed in 0.5 to 4.5 microM quinidine (n = 7), 18 to 162 microM procainamide and N-acetylprocainamide (n = 7) for comparison. 3. The results showed that the spontaneously beating heart rate and the sinoatrial (SA) and atrioventricular nodal (AH) conduction time were not significantly affected by dicentrine but were significantly suppressed by the higher doses of quinidine (4.5 microM) and procainamide (162 microM). 4. The His-Purkinje conduction time was significantly increased by the higher dose of dicentrine, quinidine and procainamide. 5. The ventricular repolarization time and its effective refractory period were significantly increased by the higher dose of dicentrine and the other agents. 6. The effective refractory period of the atrium, AV node and His-Purkinje system were also significantly increased by dicentrine and the other agents. 7. A voltage clamp study revealed that the prolongation of atrial action potential duration by dicentrine (9 microM) was associated with a significant inhibition of the transient potassium outward current. As well as inhibition of the transient outward current, a significant inhibition of the sodium inward current by dicentrine was found. 8.We conclude that (1) dicentrine is potentially a useful antiarrhythmic agent with type Ia and type III antiarrhythmic action; (2) the relative potency of dicentrine on the electrophysiological function of cardiac tissue is 10-20 times more than that of procainamide.

Surgical ablation of Wolff-Parkinson-White syndrome in children and young adults

From 1988 to 1991, nine patients with structural normal heart, aged 10 to 23 (median 13 years), Wolff-Parkinson-White Syndrome patients were operated at National Taiwan University Hospital. The diagnosis was established by surface electrocardiograms recorded during sinus rhythm and tachycardia, and by complete cardiac electrophysiologic studies. The location of accessory pathways (AP) were: 4 left lateral, 3 right lateral, 1 right posteroseptal and 1 right anteroseptal AV groove. In all 6 patients with manifest WPW syndrome, the location of AP could be correctly predicted by the surface EKG delta wave polarity. In all 9 patients with WPW syndrome, intraoperative epicardial and endocardial mappings confirmed their location. Wide endocardial dissection were undertaken. No surgical morbidities or mortality was encountered except in one case which developed transient postpericardiotomy syndrome. During the follow-up (2 to 4 years), all of them were in sinus rhythm, drug free and tachycardia free. In conclusion, (a) the sites of AP and the arrhythmia mechanisms can be reliably predicted by surface EKG and catheter mapping techniques; (b) surgical cure of supraventricular tachycardia could be achieved safely in children; and (c) surgical ablation still is indicated when catheter ablation is unsuccessful, or when coexistent complex cardiac pathology requires surgical intervention in small children.

Using microphysiometry to study the pharmacology of exogenously expressed m1 and m3 muscarinic receptors

The microphysiometer, an instrument that uses a semiconductor-based sensor to monitor cellular metabolic activity, has been shown to detect the activation of a variety of receptors in living cells, largely irrespective of the signal-transduction mechanism. Using the Cytosensor Microphysiometer, we have studied agonist concentration responses for the activation of CHO-K1 cell lines exogenously expressing rat m1 or m3 receptors. Three levels of receptor expression were investigated for each subtype. Carbachol is more potent for m3 than m1 receptors (0.5 to 1.0 log unit lower EC50); for both, potency correlates positively with receptor density. The results agree well with those obtained by measuring phosphoinositide hydrolysis and intracellular [CA++] in the same cells. We also determined that two subtype-selective antagonists, pirenzepine (for m1) and p-fluoro-hexahydrosila-difenidol (for m3) displayed appropriate differential ability to shift carbachol concentration-response curves in the microphysiometer. This study provides additional evidence that pharmacological results obtained by microphysiometry are consistent with those obtained by more conventional functional assays.

Probability of supraventricular tachycardia recurrence in pediatric patients

Supraventricular tachycardia (SVT) in pediatric patients is usually associated with a better prognosis than that in adults. However, late recurrence of SVT has been recently described. A total of 90 patients who had their initial SVT episode before 15 years of age were retrospectively studied (2-228 follow-up months; median, 215 months). Concomitantly congestive heart failure was present in 14 (16%) patients, and a cerebrovascular accident occurred in 1 patient. Intravenous verapamil was most frequently used to convert the initial SVT episodes without adverse effects, even in those younger than 1 year of age (9 patients). Older children could also be converted spontaneously or by vagal maneuvers. Patients with SVT recurrence were associated with an older age at initial SVT episodes (p < 0.001). By Kaplan-Meier actuarial analysis, the chance of remaining SVT-free during the follow-up was much lower in patients with initial SVT after 5 years of age than in patients with initial attacks before the age of 1 and between the age of 1 and 5 (p = 0.02 and 0.04, respectively). Even though, about 40% of the patients whose initial attacks occurred during infancy had recurrences 5 years later. Only those who had the initial attacks during the prenatal period remained free from SVT recurrences. Patients with initial SVT episodes during infancy have a longer period without SVT attacks and a lower chance of recurrences; nonetheless, a substantial number of them had recurrence at later childhood except those with initial SVT attacks during the prenatal period.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular stability with rapid intravenous infusion of ondansetron

The acute cardiovascular effects of rapid iv administration of the antiemetic ondansetron, a selective serotonin (5-HT3) receptor antagonist were determined in a randomized, blinded, placebo-controlled study. Measurements of heart rate, blood pressure, oxygen saturation and respiratory rate were made preoperatively over a five-minute period which followed a two-minute infusion of the medication. Intraoperative and postoperative data were not collected. None of the variables recorded changed significantly during the infusion or in the observation period which followed. Within the limitations of this study, we detected no cardiovascular change in the five minutes between the end of the drug infusion and the induction of anaesthesia.

Unregulated self-medication in an ambulatory surgery population

The objective of this study was to determine whether unregulated self-medication in an ambulatory surgery population was a significant problem in terms of the incidence and nature of drugs detected. We asked 67 consecutive patients who presented for elective ambulatory surgery at a university medical center to volunteer for serum and urine testing with the assurance of confidentiality. All patients denied nonprescription drug use. Initial testing was for amphetamines, barbiturates, benzodiazepines, cocaine, opiates, phencyclidine (PCP), tetrahydrocannabinol (THC) and alcohol. Of the 64 patients who agreed to be tested, 16 patients tested positive for at least one of the above substances; 4 patients demonstrated residua of 2 or 3 substances. No distinctive characteristic of those with evidence of drug use could be identified. We believe that the 25% of patients who tested positive in this group is a conservative estimate of possible unrecognized drug use. We have demonstrated a significant incidence of substance abuse in the ambulatory surgery environment. These findings have serious safety implications, and a higher awareness of possible nonprescription drug use in this environment is needed in medical and support personnel.

Obstructed total anomalous pulmonary venous connection

With the advent of echocardiography, total anomalous pulmonary venous connection (TAPVC) can be readily diagnosed without much difficulty. However, noninvasive detection of the presence of pulmonary venous obstruction in TAPVC remains a difficult issue. During a 5.5-year period, 42 patients were found to have TAPVC by catheterization, surgery, and/or autopsy: 17 had supracardiac drainage, 13 paracardiac drainage, nine infracardiac drainage, and three mixed drainage. Obstruction to pulmonary venous drainage was found in 24 patients (57%). Patients with right isomerism tended to have a higher incidence of pulmonary venous obstruction than those with the usual atrial arrangement (80% vs. 44%, p < 0.05). Color Doppler combined with cross-sectional echocardiography provided accurate delineation of drainage sites in 93% cases (39 of 42). Among the 39 cases with correct echocardiographic delineation of the drainage site, obstruction was detected by echocardiography in 22 cases with a sensitivity of 100% (22 of 22) and a specificity of 85% (17 of 20). Therefore, complete echocardiography, including cross-sectional images and color Doppler proved to be a reliable tool in the detection of drainage sites and pulmonary venous obstruction in TAPVC.

Role of Pseudomonas aeruginosa outer membrane protein OprH in polymyxin and gentamicin resistance: isolation of an OprH-deficient mutant by gene replacement techniques

The cloned oprH gene of Pseudomonas aeruginosa was mutated by inserting a 1.4-kbp fragment that encodes tetracycline resistance. This mutated gene was then incorporated into the P. aeruginosa chromosome by homologous recombination. Growth of the resultant oprH::tet mutant in Mg(2+)-deficient medium had little effect on susceptibility to polymyxin B, gentamicin, or EDTA unless the mutant was complemented by the cloned oprH gene in plasmid pGB25. In contrast, growth of the parent strain on Mg(2+)-deficient medium resulted in resistance to all three agents. These data support the hypothesis that overexpression of OprH under Mg(2+)-deficient growth conditions is conditionally required for resistance to these three agents.