Application of flow cytometry in the study of apoptosis in neonatal rat cardiomyocytes.

Depending on the concentration, catecholamines activate various intracellular signaling pathways and can induce apoptosis in cardiac myocytes. Although 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine iodide (JC-1) has been previously used to study mitochondria in intact cardiomyocytes, there have been no reports on the detection of apoptosis in neonatal cardiomyocytes in combination with flow cytometry and confocal microscopy. In our study, neonatal rat cardiomyocytes were exposed to norepinephrine (NE) and isoproterenol (ISO) in concentrations of 1 and 10 microM for 48 h. NE concentrations of 1 and 10 microM decreased the number of viable cardiomyocytes by 18% (*p < 0.05) and 24% (**p = 0.01), respectively. ISO in a concentration of 1 microM increased the number of viable cardiomyocytes by 13% while 10 microM decreased the number of viable cardiomyocytes by 43% (***p < 0.001). Apoptotic cells were detected by flow cytometry and confocal microscopy. NE in concentrations of 1 and 10 microM increased the percentage of apoptotic cells by 12.2% and 34.3%, respectively, while ISO alone in a concentration of 10 microM increased the percentage of apoptotic cells by 11.3%. The results demonstrated that these two methods are reliable and suitable for the detection and study of apoptosis in cultures of neonatal cardiomyocytes.

Intracardiac juvenile xanthogranuloma in a newborn.

Juvenile xanthogranuloma (JXG) presents a normolipemic non-Langerhans cells histiocytosis. JXG usually presents with cutaneous lesions. Visceral involvement is rare but may affect various organs. Deep JXG differs histologically from the cutaneous form by its tendency to consist solely of homogeneous proliferation of histiocytes without any xanthomatous or Touton giant cells. Awareness of the possibility of this atypical presentation of JXG helps in making the correct histologic diagnosis, which is supported by proving adequate immunomarkers on histiocytes (mainly PG-M1, an antibody against the CD68 antigen). JXG may present with intramuscular lesions only; however, rarely JXG has been reported to affect the heart but not without the typical cutaneous manifestations. We present an unusual case of deep JXG without systemic disease or metabolic abnormalities. To our knowledge, this is a first reported case of intracavitar JXG without skin lesions.

Radioangioscintigraphy and Doppler echocardiography in the quantification of left-to-right shunt.

The magnitude of left-to-right shunt in 55 children with isolated congenital heart disease [atrial septal defect (ASD) or ventricular septal defect (VSD) (muscular and perimembranous)] was estimated by two methods: radionuclide quantification and Doppler echocardiography [flow (L/min) = mean velocity x area x ejection time x heart rate]. We found little difference between the magnitude of left-to-right shunt obtained with Doppler echocardiography and that with radioangioscintigraphy for a whole group of patients (N = 55, -11.42% to 12.04%) and for subgroups of ASD (n = 24, -12.49% to 12.19%) and VSD (n = 31, -10.69% to 12.23%). These results indicate that Doppler echocardiography, in comparison with radioangioscintigraphy, is sufficiently accurate for clinical estimation of the Q(p)/Q(s) ratio in isolated congenital heart disease with left-to-right shunt.