Evidence that granule cells generated in the dentate gyrus of adult rats extend axonal projections.

Fully mature rats were injected intraperitoneally with 3H-TdR on postnatal day (P) 100. After an additional 28-32 days, a retrograde fluorescent tracer, either FB or DY, was injected into the regio inferior of the hippocampal formation to label granule cells of the dentate gyrus through their mossy fiber axons. Examination of autoradiographs from these brains reveals that 3H-TdR labeled cells within the granule cell layer of the dentate gyrus are often labeled with the retrograde tracer as well. This indicates that within the mature hippocampal formation, newly generated dentate granule cells are capable of extending axonal projections for considerable distances.

Focal necrosis of the white matter (periventricular leukomalacia): sonographic, pathologic, and electroencephalographic features.

Eleven preterm infants (gestational ages 27-35 weeks) with echogenic paraventricular white matter identified shortly after birth were studied with serial echoencephalograms to fully delineate the sonographic findings characterizing the pathologic stages of white-matter necrosis. Echoencephalograms were compared with autopsy findings and CT scans. Cerebral function was assessed by electroencephalograms and later by neurodevelopmental evaluations. Echogenic areas were observed in the paraventricular white matter in the acute stage. Microscopically, the echogenic white matter consisted of vascular congestion and petechial hemorrhages, but not always with foci of necrosis. Anechoic areas, which characterized the chronic stage, corresponded to cavitary lesions, and these generally appeared within 2 weeks of birth. However, six infants had anechoic lesions by day 4, suggesting that the onset of white-matter damage was antenatal. CT showed mildly decreased attenuation when paraventricular echogenic areas alone or in association with small anechoic areas were observed. Markedly decreased attenuation on CT scans corresponded to large anechoic areas. Resolution of the sonographic and CT findings did not indicate normalization of the white matter since all surviving infants were neurologically abnormal at 1 year. Electroencephalograms with central (rolandic) positive sharp waves were associated with echogenic white matter alone or with evolving anechoic areas. All patients with positive sharp waves on electroencephalograms had large anechoic areas in later studies. Early and serial echoencephalograms are necessary to evaluate white-matter necrosis in preterm infants. When echogenic white matter is identified, electroencephalography can suggest the presence of white-matter necrosis.

Alterations in serum glucose and hepatic glycogen concentrations during octanoate administration in rabbits.

During continuous administration of sodium octanoate (0.2 M) into weanling and mature rabbits, a significant decrease in serum glucose concentration was observed within 15 minutes after onset of the infusion. This relative hypoglycemia persisted for as long as one hour, after which there was a rebound to normoglycemia. Hepatic glycogen concentrations were correspondingly reduced by one-half in octanoate-treated versus control animals. Previous studies in an octanoate model have demonstrated clinical, biochemical, and pathologic features similar to those found in Reye syndrome. The current findings may have implications for the hypoglycemia observed in children with Reye syndrome.

Multiple cerebral defects in an infant exposed in utero to anticonvulsants.

A female infant exposed in utero to anticonvulsant therapy had bilateral encephaloceles, ventricular abnormalities, and defective neuronal migration. This is one of a few articles with pathologic data available that discusses central nervous system involvement in infants exposed to anticonvulsants.

Thrombotic thrombocytopenic purpura during penicillamine therapy in rheumatoid arthritis.

Thrombotic thrombocytopenic purpura (TTP) developed in a patient with seropositive rheumatoid arthritis (RA) after 2 1/2 months of treatment with penicillamine. After discontinuation of the drug, plasmapheresis and steroid therapy led to a sustained remission. To our knowledge, no prior cases of penicillamine-induced TTP in RA have been reported.

Infantile osteopetrosis and neuronal storage disease.

Infantile osteopetrosis often presents with neurologic symptoms that cannot always be attributed to primary bone disease of the skull. We studied an infant with osteopetrosis and pathologic evidence of neuronal and axonal changes. This is the third case in which primary parenchymal disease of the brain was associated with infantile osteopetrosis and the first in which neuronal cytoplasmic storage was documented by light and electronmicroscopy. The simultaneous occurrence of two rare autosomal-recessive disorders, each possibly caused by an inherited lysosomal enzyme deficiency, may not be fortuitous.

Enlarged cerebrospinal fluid spaces in infants with subdural hematomas.

Computed tomography in 16 infants with subdural hematomas showed enlarged basal cisterns, a wide interhemispheric fissure, prominent cortical sulci, and varying degrees of ventricular enlargement. Radionuclide cisternography in eight of the 16 patients showed findings consistent with enlargement of the subarachnoid space rather than those of communicating hydrocephalus. Clinical findings and brief follow-up showed no convincing evidence for cerebral atrophy in 13 patients. These findings suggest that the enlarged subarachnoid space, which is encountered in some infants and may be a developmental variant, predisposes such infants to subdural hematomas.

Pineoblastoma with ganglionic and glial differentiation: report of two cases.

Two cases of pineoblastoma in infants are reported. Both cases exhibited ganglionic and astrocytic differentiation, and one case also showed retinoblastomatous features. Divergent differentiation has been frequently reported in pineocytomas, but ganglionic and glial features in the highly malignant primitive pineoblastoma are unusual. These cases extend the concept of pineoblastoma and further confirm the differentiating potential of primary pineal parenchymal neoplasms.