Biomedical subjects
Publications and source records attributed to T Izukawa.
We report a 14 year old boy who presented as a neonate with functional pulmonary atresia due to Uhl's disease with emphasis on the later detection of restrictive right ventricular physiology.
An N-linked sugar chain from 55-kDa royal jelly glycoprotein (RJGP), which maintains the high viability of rat liver primary cultured cell and is a different molecular species from 350-kDa RJGP [Kimura et al., Biosci. Biotech. Biochem., 59, 507-509 (1995)], has been identified. The sugar chains were released by hydrazinolysis followed by N-acetylation and pyridylamination. The structural analysis of the pyridylaminated sugar chain was done by a combination of sequential exo-mannosidase digestions, MALDI-TOF MS, and 500 MHz 1H-NMR. For the carbohydrate moiety of 55-kDa RJGP, only one N-linked sugar chain has been detected. The structure has been found to be Man alpha 1-->2Man alpha 1-->6(Man alpha 1--> 2Man alpha 1-->3)Man alpha 1-->6(Man alpha 1-->2Man alpha 1-->2Man alpha 1-->3)Man beta 1-->4GlcNAc beta 1-->4GlcNAc, which is a non-processed high mannose type structure.
Atypical mycobacterium is rare in children. There are few case reports of childhood pulmonary diseases caused by atypical mycobacterium. The case of a 20-month-old boy who had stridor and respiratory distress is presented. Chest x-ray showed right-sided narrowing of the trachea and left-sided aortic knob. Ziehl-Neelsen stain showed acid-fast bacilli. The culture showed Mycobacterium malmoense.
Nineteen infants < 6 months old who had atrial ectopic tachycardia (AET) were treated with antiarrhythmic drugs. AET was controlled with digoxin in 1 patient, propafenone in 2, digoxin with propafenone in 9, digoxin with amiodarone in 4, and digoxin with propafenone and amiodarone in 2; radiofrequency ablation was performed in 1 drug-resistant case. AET resolved in 14 of 15 infants within 1 year. Drug side effects occurred in 5 patients. We conclude that AET in infants < 6 months old can be successfully treated with antiarrhythmic drugs, and we recommend a three-step approach with digoxin, a class 1C antiarrhythmic drug, and a class 3 drug. Resolution of AET in infants is frequent.
To determine the sequelae of transient myocardial ischemia (TMI) in term infants, we reviewed clinical and investigative data in 59 infants (37 male, 22 female) with structurally normal hearts admitted over the 2-year period of 1983-1985. Twenty-three were diagnosed prior to admission as cases of birth asphyxia (5-min Apgar score less than 6), and 36 had signs of persistent fetal circulation with electrocardiographic (ECG) changes of ischemia greater than 24 h after birth. Murmurs of atrioventricular valve regurgitation (AVVR), detected in 28 patients, were confirmed in 23 of the 24 patients investigated. The murmurs resolved over a 2-day to 6-month period (median 6 days). In three patients, AVVR, left ventricular dyskinesia, and ECG anomalies persisted for 2 months (until death), 4 months, and 48 months. Initial ECGs were abnormal in 57 patients, and (of those reviewed) 60% returned to normal over a 6-day to 7-month period (median 2 months). Residual ECG anomalies included second-degree AV block and persistent ST-T wave changes. Ten patients died from noncardiac causes. Neither the presence nor resolution of AVVR correlated significantly with the severity of birth asphyxia using the Apgar score, nor with the severity of the ischemic changes on the ECG. Although the cardiovascular sequelae of myocardial ischemia are usually transient, the data should prompt the need for careful review after the initial admission.
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Congenital arteriovenous fistulas presenting in the newborn period pose difficult diagnostic problems and simulate structural heart disease. Angiocardiography, when performed, demonstrates enlarged brachiocephalic vessels and rapid cerebral venous return. The value of echocardiographic imaging and measurement of the aortic arch and brachiocephalic vessels, and evaluation of the Doppler flow profile in these vessels as a means of making a rapid diagnosis of cerebral or thoracic arteriovenous fistula, was therefore assessed in 10 infants with these diagnoses seen over a 4 year period (1983 to 1987). Twenty-nine infants (median age 6 weeks) undergoing two-dimensional echocardiography but with no significant lesions were prospectively selected as controls. Nine of the 10 patients had congestive heart failure at presentation (mean age 2 days). A cranial bruit was heard in three and arteriovenous fistula was suspected in five patients. Aortic arch segments and brachiocephalic vessel dimensions expressed as ratios of the abdominal aorta showed significantly larger values in patients for the ascending aorta (p = 0.01), innominate artery (p less than 0.001), right and left subclavian arteries (p less than 0.001) and left common carotid artery (p less than 0.05). The thoracic descending aorta was, however, significantly smaller in patients (p less than 0.002). Retrograde diastolic Doppler flow in the descending aorta proximal to the ductus arteriosus and anterograde diastolic flow with a mean spectral flow-time integral 27% of systolic were present in patients only, whereas Doppler diastolic flow in brachiocephalic vessels, present in 5 of 29 control infants, was less than 15% of systolic flow and not accompanied by dilation of these vessels.(ABSTRACT TRUNCATED AT 250 WORDS)
Inferences: A treatment protocol for patients with simple transposition, consisting of initial balloon atrial septostomy and leading to a delayed atrial switch repair of the Mustard type, in good circumstances, results in survivorship at 1 month, 1 year, 10 years, and 20 years of 95% (95% confidence limits [CL] 90% to 97%), 90% (95% CL 84% to 94%), 83% (95% CL 74% to 90%), and 80% (95% CL 70% to 88%), respectively. Low birth weight adversely affects survivorship. Hypoxia or heart failure accounts for most deaths within the first month and before the atrial switch (Mustard) repair. Most of the few deaths late postoperatively are sudden and they appear to occur particularly in patients who have junctional rhythm. A progressive increase in the prevalence of junctional rhythm has been a risk of the atrial switch repair, and only 76%, 65%, 59%, 56%, and 53% of patients can be expected to be free of this by 1, 5, 10, 15, and 20 years after repair. Important right ventricular dysfunction late after an atrial switch repair, with its adverse affect on the patients' functional capacity, appears to be present in up to 10% of patients after the atrial switch repair, but may not be an immutable risk of this type of repair. About 90% of patients, essentially all of those who do not have right ventricular dysfunction, can be expected to be in New York Heart Association class I or II late postoperatively.
From May 1963 to December 1985, 329 infants and children underwent repair of simple transposition of the great arteries (TGA) using Mustard's technique. To assess improvement, the patients were separated into two groups by date of operation: Group I, May 1963 to December 1973 (N = 106), and Group II, January 1974 to December 1985 (N = 223). The operative mortality was 11 (10.4%) in Group I and two (0.9%) in Group II. The 10-year actuarial survival rate was 73.4% in Group I and 93.7% in Group II. Baffle complications, similar in both groups, were identified in 81 patients; 19 were major, causing death or requiring reoperation. By latest electrocardiogram, 21 of 45 (46.7%) of Group I patients and 129 of 180 (71.7%) of Group II patients were in normal sinus rhythm. Late ambulatory electrocardiography, however, revealed that a majority of patients had sinus node dysfunction or other dysrhythmias. Right ventricular (RV) angiography revealed definite diminution of RV contractility in 14 (11%) of 126 children. At late follow-up, 113 of 148 (76%) children were in New York Heart Association (NYHA) Class I and 35 of 148 (24%) were in NYHA Class II. Thirty-five (21%) patients were on cardiac medication chiefly for dysrhythmia management. There has been significant improvement in the early and late mortality with the Mustard operation, and serious baffle complications are infrequent. Dysrhythmias continue to be a major problem but the surviving patients are clinically well and relatively few have significant RV dysfunction.
Patch graft angioplasty is an accepted technique for the repair of some forms of coarctation and for recoarctation. Since 1970, 63 patients at our institution underwent 65 operations for repair of coarctation (ages 3 days to 32 years); in 27 it was the initial operation and 38 needed surgery for recoarctation. Average follow-up was 3.5 years (range 3 months to 14 years). There was one death, 20 patients with persistent hypertension, and eight patients with a persistent arm/leg pressure gradient (14 to 30 mm Hg at rest). Five patients required reoperation, two for recoarctation and three for aneurysm formation. The aneurysms were found on routine chest x-rays 3, 3.7, and 13.5 years after surgery. All aneurysms were repaired with left heart bypass in which a Dacron tube graft was used without complications. Synthetic patch angioplasty to repair coarctation was effective; however, aneurysm formation was a late complication in 5% of our patients. All patients undergoing patch repair should be followed on a yearly basis to allow early detection of aneurysms.
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Two hundred nine children with congenital heart defects characterized by excessive pulmonary blood flow underwent pulmonary artery banding at The Hospital for Sick Children from January, 1972, through December, 1982. The indications for banding, rather than complete repair, varied with the type of cardiac defect as well as with the year of presentation to our hospital. A simplified method of estimating required band circumference has been developed for infants with ventricular septal defect, with or without major intracardiac mixing disorders. Infants with simple defects without intracardiac bidirectional mixing disorders receive a band at a circumference of 20 mm + 1 mm for each kilogram of body weight, whereas infants with bidirectional mixing disorders receive a band at a circumference of 24 mm + 1 mm for each kilogram of body weight. The overall operative mortality varies with the underlying cardiac defect and with associated medical conditions but is relatively low in the less-complicated cases. The use of a formula to predict a starting band circumference, with loosening only as required by cyanosis or bradycardia, allows predictable control of congestive symptoms and pulmonary hypertension in the majority of infants. The cumbersome measurement of pulmonary artery pressure and the unpredictable changes in pressure during anesthesia are avoided. Pulmonary artery banding remains an effective means of achieving satisfactory palliation in infants with congenital heart disease and excessive pulmonary blood flow.
We collected data on 930 neonates with structural congenital heart disease seen during 1975-1977 at the existing pediatric cardiac referral and treatment centers in Ontario. Estimates were made of unmet need for pediatric cardiology services in Ontario. The data showed that a number of counties had significantly low referral rates and that at least 25% of the newborns with severe structural heart disease (that is, 75 newborns each year) were not seen by pediatric cardiologists, although the children would benefit from prompt assessment and rapid treatment under specialist supervision.
Four patients with space-occupying myocardial lesions were studied using electronically focused high-resolution two-dimensional echocardiography. In two patients with clusters of high-intensity echoes at various depths on the epicardial surface, histology confirmed the diagnosis of lymphosarcoma, showing patchy, malignant infiltrates of different thickness. The remaining two patients had very different features: the lesions appeared to be intrinsic to the posterior left ventricular wall. One patient who had arrhythmias and a small encapsulated noncontractile mass had a histologically proved rhabdomyoma. In the second patient fibroma was histologically confirmed. In these two patients the position of the lesions was confirmed by angiocardiography. Two-dimensional echocardiography greatly improved delineation of space-occupying cardiac masses and is an accurate method for confirming the presence of such lesions.
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Patent ductus arteriosus was diagnosed in 239 neonates of low birth weight (less than 2500 g) referred to the Hospital for Sick Children in a 21/2-year period. The respiratory distress syndrome was present in 77% of the group and congestive heart failure in 50%. Spontaneous closure of the defect was more frequent in those without congestive heart failure. In 48 patients whose heart failure could not be controlled by other medical therapy indomethacin was given, and in 20 (42%) it was judged successful. Surgical ligation of the ductus was performed at a median age of 30 days in 33 infants who either failed to respond to indomethacin or in whom its use was contraindicated; there were no intraoperative deaths, but 11 (33%) of the infants died 4 days to 6 months after the operation.