Predicting Long-Term Ventricular Arrhythmia Risk in Children with Acute Lymphoblastic Leukemia Using Normal Values of Ventricular Repolarization Markers Established from Japanese Cohort Study.

BACKGROUND: Cardiac complications due to anthracycline treatment may become evident several years after chemotherapy and are recognized as a serious cause of morbidity and mortality in cancer patients or childhood cancer survivors. OBJECTIVES: We analyzed ventricular repolarization parameters in electrocardiography for pediatric acute lymphoblastic leukemia patients during chemotherapy and in long-term follow-up. To establish the reference values of ventricular repolarization parameters in children, we retrospectively summarized the Tpe interval, QT interval, QTc interval, and Tpe/QT ratio in healthy Japanese children. METHODS: Electrocardiography data recorded from students in 1st and 7th grades were randomly selected from a database maintained by the school-based screening system in the Oita city cohort, Japan. Subsequently, chronological data of the Tpe/QT ratio in 17 pediatric patients with acute lymphoblastic leukemia were analyzed over time. RESULTS: The mean ± standard deviation of the Tpe interval in 1st and 7th graders was 70 ± 7 and 78 ± 17 ms, respectively, while the mean ± standard deviation of the Tpe/QT ratio was 0.21 ± 0.02 and 0.22 ± 0.02 ms, respectively. During the intensive phase of treatment, the Tpe/QT ratios of 3 high-risk patients among the 17 patients with acute lymphoblastic leukemia exceeded the upper limit. CONCLUSION: The Tpe/QT ratio has a potential clinical application in predicting the risk of long-term ventricular arrhythmia of cancer patients or childhood cancer survivors from childhood to adulthood.

Vitamin D deficiency associated with dilated cardiomyopathy in early infancy caused by maternal cholestasis.

Breast feeding is known to be a major cause of vitamin D deficiency in infants because the content of vitamin D in breast milk is significantly lower than that in formula. We report a case of a 1-mo-old boy who developed hypocalcemic seizures and dilated cardiomyopathy caused by vitamin D deficiency despite being fed a sufficient amount of regular formula. The cause of vitamin D deficiency in this case was maternal vitamin deficiency due to severe hyperemesis and insufficient sunlight exposure, induced mainly by the malabsorption of fat-soluble vitamins caused by maternal cholestasis. We should carefully consider maternal conditions during pregnancy and the postpartum period to detect and prevent vitamin D deficiency in the fetus and infant.

Cell distribution differences of matrix metalloproteinase-9 and tissue inhibitor of matrix metalloproteinase-1 in patients with Kawasaki disease.

The interaction of matrix metalloproteinase (MMP)-9 and tissue inhibitor of matrix metalloproteinase-1 has been implicated in the formation of coronary aneurysms in Kawasaki disease. MMP-9 and tissue inhibitor of matrix metalloproteinase-1 were distributed predominantly in the granulocytes and platelets, respectively, in patients with Kawasaki disease. The plasma values of MMP-9 correlated positively with the circulating neutrophil count. Inhibiting the activity of granulocytes and maintaining the platelet activity might prevent coronary aneurysms.

Detection of platelet-binding anti-measles and anti-rubella virus IgG antibodies in infants with vaccine-induced thrombocytopenic purpura.

A 15-month-old infant presented with thrombocytopenic purpura after sequential administration of measles-rubella combined vaccine, varicella vaccine and mumps vaccine every 4 weeks. Her thrombocytopenia persisted for more than 12 months. Both anti-measles and anti-rubella virus IgG antibodies were detected in the patient's-isolated platelets on day 154 of illness, which were not detected when there was a reduction of the serum IgG antibody titers on days 298 and 373 of illness, respectively.We also detected the isolated platelet-binding anti-measles and anti-rubella virus IgG antibodies in two other pediatric patients. This is the first report demonstrating direct evidence of vaccine-induced thrombocytopenic purpura.