Findings on endomyocardial biopsy in infants and children with dilated cardiomyopathy.

Fifteen infants and children with dilated cardiomyopathy underwent transvascular endomyocardial biopsy. The light and electron microscopic findings were reviewed to evaluate the presence of lymphocytes as an indicator of active myocarditis. Both ventricles were biopsied in 13 patients, and the right ventricle only was biopsied in 2. None of the endomyocardial specimens obtained by biopsy revealed an inflammatory process. Interstitial fibrosis, myofiber hypertrophy, degeneration and necrosis were found. Ultrastructural abnormalities of the mitochondria, T tubules or Z bands were noted in approximately one-third of patients. Persistent, active myocarditis is an uncommon cause of dilated cardiomyopathy in children. Immunosuppressive therapy, which may be harmful, should be considered only after myocardial inflammation has been documented by endomyocardial biopsy.

Histiocytoid cardiomyopathy of infancy: deficiency of reducible cytochrome b in heart mitochondria.

A 3-week-old girl with failure to thrive and cardiomegaly died of cardiac arrest at age 4 weeks. Morphologic studies of the heart showed enlarged muscle fibers with large accumulations of mitochondria, characteristic of histiocytoid cardiomyopathy. Biochemical studies showed markedly decreased succinate-cytochrome c reductase and rotenone-sensitive NADH-cytochrome c reductase activities, while other mitochondrial enzymes were normal. In isolated mitochondria, cytochrome spectra showed a severe defect of reducible cytochrome b and a less marked defect of cytochrome cc1, while the content of cytochrome aa3 (cytochrome c oxidase) was normal. Histiocytoid cardiomyopathy appears to be due to a defect of complex III (reduced coenzyme Q-cytochrome c reductase) in the respiratory chain of heart mitochondria.

Neonatal cholestasis and hypopituitarism.

The diagnosis of optic nerve hypoplasia and hypopituitarism must be entertained in infants who present for evaluation of cholestatic jaundice, particularly if there is associated hypoglycaemia and wandering nystagmus. Although the hepatic dysfunction seems to resolve, the long term prognosis of liver disease in optic nerve hypoplasia remains unknown.

Invasive properties of primary pediatric neoplasms in vitro.

Primary solid tumors were mechanically and/or enzymatically disassociated, and the resulting suspensions of single cells and small clumps of cells were seeded onto three different substrates, i.e., tissue culture plastic, rat smooth muscle cells (SMCs), and SMC-derived extracellular matrix. Tests of the relative effectiveness of these substrates in supporting the survival and/or growth of ten different neoplasms demonstrated that only two explants remained viable for longer than 2 weeks when seeded onto tissue culture plastic while nine of the ten survived on biological substrates for 1 month or longer. Thus, tissue culture plastic was a poor substrate for primary pediatric neoplasms. In general, more than 80% of the most common solid neoplasms in childhood (brain tumor, neuroblastoma, renal tumor, rhabdomyosarcoma, osteogenic sarcoma, and Ewing's sarcoma) routinely survived or grew in long-term cultures when cultured onto SMCs or their matrix. Both substrates were effective in promoting survival and/or growth; however, cells of neuroblastomas and certain brain tumors showed a preference for a living smooth muscle substrate. Tumor cells maintained their characteristic cellular and subcellular morphology when compared with the histology of the in vivo neoplastic lesions. Light and electron microscopy of selected neoplasms cultured on SMCs for various time periods demonstrated areas of distinct cellular invasion and/or partial destruction of the SMC multilayers which correlated with the invasive potentials of the neoplasms in patients. Invasion and destruction of the SMCs were also noticed with quiescent tumor cell cultures, indicating that growth was not a necessary property of invasion. Several neoplasms were also capable of the degradation of connective tissue proteins as indicated by the hydrolysis of radiolabeled SMC matrices, but simple correlations between the extent of matrix degradation and invasive ability could not be drawn. The culture system described consistently provided for the survival and/or growth of the most common pediatric tumors for long time periods. Thus, basic biological properties of primary tumors, e.g., growth, invasive potentials, and differentiation capabilities, could be investigated routinely.

Restrictive cardiomyopathy with pseudotumor formation of the left ventricle.

A 4-year-old girl had the insidious onset of congestive heart failure without apparent cause. Evaluation by echocardiography, thallous chloride TI 201 scintigraphy, and angiography suggested the presence of either a neoplasm or restrictive cardiomyopathy with a localized mass effect on the left ventricle. Pathological specimens obtained by transvascular endomyocardial biopsy and at surgery defined the pathology to be restrictive cardiomyopathy. Analysis of myocardium by electron microscopy demonstrated a previously undescribed abnormality of the contractile elements involving the myofilaments and Z bands, with generalized secondary glycogen deposition.

Invasion of an artificial blood vessel wall by human fibrosarcoma cells.

Artificial blood vessel walls constructed by the addition of bovine arterial endothelial cells to multilayers of rat smooth muscle cells were used as substrates for the human fibrosarcoma cell line HT1080. The extracellular matrix proteins elaborated by the smooth muscle cells were prelabeled with [3H]-proline; therefore, their subsequent digestion could be followed by the appearance of radioactivity in the culture medium. The fibrosarcoma cells rapidly hydrolyzed smooth muscle multilayers in the absence of endothelial cells, but an endothelial layer markedly retarded the destructive ability of the tumor cells. The protective effect of the endothelium was not due to a lack of penetration of this cell layer, since HT1080 cells were observed by light and electron microscopy to be in the subendothelial area 24 hr after plating. Subsequently, the tumor cells multiplied in the region between the endothelial and smooth muscle layers and, although their degradative ability was retarded, they were ultimately capable of destroying the structure. Endothelial cells also inhibited hydrolysis of the smooth muscle layers if added simultaneously or up to 1 week after HT1080 cells, but the degree of inhibition was not as great as that seen with a preestablished endothelial layer. Measurable inhibition of tumor cell degradative activity was observed at fibrosarcoma:endothelial cell ratios of 25:1, demonstrating the potency of endothelial cells in modulating this aspect of the invasive phenotype. Although the HT1080 cells only slowly degraded the preexisting matrix proteins in artificial vessel wall cultures, they interfered with the production of new connective tissue proteins which occurred in control cultures. These experiments therefore suggest that endothelial cells have profound effects on tumor cell proteolytic activity, and the significance of these observations to tumor cell extravasation in vivo is discussed.

Kartagener's syndrome with absence of inner dynein arms of respiratory cilia.

Morphologic abnormalities of spermatozoa and respiratory cilia at the electron microscopic level have been described in the immotile-cilia syndrome and chronic respiratory diseases. Most often there has been a total absence of the dynein arms. The current report describes absence of only the inner dynein arm in respiratory cilia from a patient with Kartagener's Syndrome, thus recording another variation in the abnormality of ciliary morphologic features believed to be recessive inherited.

An X-linked recessive cardiomyopathy with abnormal mitochondria.

A transvascular endomyocardial biopsy from an infant with cardiomyopathy and chronic congestive heart failure showed abnormal mitochondria when examined by electron microscopy. At necropsy, similar abnormal mitochondria were seen in skeletal muscles, liver, and kidney. The patient's family pedigree revealed several male babies who had cardiac disease and died in infancy. Myocardium obtained at necropsy from three cousins contained mitochondria with abnormalities similar to those from the proband. An X-linked recessive cardiomyopathy seems likely in this family.

Endocardial fibroelastosis found on transvascular endomyocardial biospsy in children.

Left ventricular endocardium obtained by transvascular endomyocardial biopsy from nine infants and children with various congestive cardiomyopathies showed thickening in five, with hyperplasia of endocardial cells and increase in elastic and collagen fibers (endocardial fibroelastosis). Based on the morphologic findings, we suggest a chronologic sequence of hyperplasia of smooth muscle (SM) cells followed by transformation and translocation. The sequence appears to be (1) proliferation of dark SM cells with many surface vesicles, many myofilaments, and fusiform densities; (2) possible proliferation of light SM cells containing fewer surface vesicles and fewer myofilaments than the dark SM cells; (3) transformation of SM cells to leiomyoid cells that resemble both SM cells and fibroblasts; and (4) transformation to typical fibroblasts. The cells producing the increased elastin and collagen are believed to be the SM cells and the leiomyoid cells.

Transvascular endomyocardial biopsy in infants and small children. Myocardial findings in 10 cases of cardiomyopathy.

Transvascular endomyocardial biopsy specimens from nine children with congestive cardiomyopathy and one with hypertrophic cardiomyopathy were studied by light microscopy using sections 1 mu thick cut from Epon embedded tissue and by electron microscopy. There was a disparity between the severity of the physiologic impairment and the morphologic abnormalities. Interstitial fibrosis was present only in the one case in which significant viral antibody titers were obtained. The sizes of the cardiac muscle cells varied abnormally in all specimens. Cardiac muscle cells in two patients contained abnormal mitochondria, and a leptomeric fibril was found in one patient. Virologic cultures of the tissues were negative and no viral particles were identified by electron microscopy. An attempt was made to correlate the clinical and pathologic findings.

Hepatic sinusoidal cells in iron overload. Ultrastructural observations.

The ultrastructure of sinusoidal cells was studied in 18 liver biopsies from patients with homozygous beta-thalassemia. No conspicuous iron was seen in sinusoidal cells from biopsies obtained before transfusion therapy was initiated, although electron-dense iron was present in some parenchymal cells. Biopsies following the high transfusion regime showed progressive increase in the size and number of iron-containing lysosomes in both parenchymal and sinusoidal cells. This study confirms the view that transfusional iron is largely segregated in reticuloendothelial cells. Examination of stained and unstained sections showed the Kupffer cells and endothelial cells had different types of iron-containing lysosome that were also dissimilar from most iron-containing lysosomes seen in hepatocytes. The described cell-specific morphological features of the lysosomes facilitate the identification of various cells during iron overload. The importance of phagocytic sinusoidal cells during chronic iron overload is stressed.

Transvascular endomyocardial biopsy in infants and small children: description of a new technique.

A miniaturized technique for transcatheter endomyocardial biopsy has been developed in the belief that myocardial biopsy performed in infancy, when the disease process in cardiomyopathy may be most active, should yield important etiologic and nosologic information. To obtain six biopsy specimens, three from each ventricle, adds about 1 hour to a diagnostic right and left heart catheterization. A no. 4 or 5 French forceps with a modified soft shaft is guided to the site in theapical septum of the right and left ventricles through a previously molded to measure guide tube of ultrathin radiopaque Teflon. With biplane fluoroscopy the guide tube of ultrathin radiopaque Telflon. With biplane fluorsocopy the guide tube is introduced as a sheath over a matching catheter and the catheter is removed. Contrast medium in injected to verify position, the forceps is introduced and the biopsy specimen is taken. If the forceps is sharp and pressure on the endocardium in light, evidence of biopsy is not discrenible on examination of the heart 1 week later. The method was developed in small dogs and proved safe and effective in rabbits weighing 3 kg. Biopsy has been performed safely in children aged 4 1/2 months to 5 1/2 years and weighing 4.5 to to 19.6 kg.

Ferritin in human liver cells of homozygous beta-thalassaemia: ultrastructural observations.

Homozygous beta-thalassaemia is a disease in which there is a progressive iron overload from infancy to death in early adulthood. Liver biopsies from 10 patients in various stages of this disease were examined by electron microscopy. A number of round or oval lysosomal structures, containing lamellae different from myelin figures, were seen in all patients, including those with minimal iron overload. Ferritin molecules were seen either in relationship with the lamellae forming arrays, or in paracrystalline arrangement, or with no organized form. There were practically no ferritin molecules in sub-cellular compartments other than cell sap and lysosomes. The density of cell sap ferritin was constant beyond infancy, but the number of iron-laden lysosomes increased with age. The stages in the process of iron seclusion, seen even in advanced phases of iron overload, are described. Ferritin is thought to accumulate in lysosomes by a transmembraneous movement, but other explanations are considered.

Cadaver renal transplantation in children with cystinosis.

Five children with end-stage renal disease resulting from cystinosis received seven cadaver renal allografts. Four recipients have functioning grafts eight to 55 months after receiving the transplant and one recipient lost two grafts at 17 and 26 months after the transplant. There was no florid recurrence of the Fanconi syndrome although proximal renal tubular dysfunction developed in two patients, in one in association with chronic rejection and in one without apparent etiology. Free cystine content of white blood cells, cultured skin fibroblasts and allograft tissue was significantly increased. Cystine crystals were observed in the mesangium of two grafts and in the interstitial tissue of all grafts; however, no cystine crystals were found in the tubules. The location of the cystine crystals, as well as the fact that the highest free level of cystine of allograft tissue was observed in the graft undergoing chronic rejection. led to the hypothesis that recipient cells infiltrating the graft were the source of cystine deposition. The data indicate that successful cadaveric transplantation does not correct the primary metabolic defect in cystinosis, thereby explaining the persistence of the extrarenal clinical manifestations, such as photophobia and hypothyroidism, after renal transplantation in cystinosis.

Ultrastructural abnormalities of liver cells in Reye's syndrome.

Electon microscopic observations were made on liver biopsy specimens from nine infants and children diagnosed as having Reye's syndrome by clinical, laboratory, and light microscopic criteria. In addition to excessive fat content, mitochondrial abnormalities were the most frequent abnormal finding in the liver. However, no correlation could be established between the severity of mitochondrial changes and clinical or biochemical data, and two patients with low levels of the first two urea cycle enzymes showed only mild mitochondrial abnormalities. Nonspecific or artifactual factors have been suggested to explain the mitochondrial changes. However, the data of this study suggest that most of the reported mitochondrial abnormalities are not artifacts, and that they can be helpful in the ultrastructural diagnosis of Reye's syndrome.