Altered development of prefrontal neurons in rhesus monkeys with neonatal mesial temporo-limbic lesions: a proton magnetic resonance spectroscopic imaging study

Focal brain damage occurring early in development can have widespread repercussions throughout the developing brain. In living adult rhesus monkeys, we studied the long-term effects of early mesial temporo- limbic (MTL) lesions on prefrontal cortex (PFC) neurons using proton magnetic resonance spectroscopic imaging (1H-MRSI), an in vivo neurochemical assay technique for measuring signals from metabolites such as N-acetyl-aspartate (NAA, a neuronal marker), choline-containing compounds (CHO) and creatine + phosphocreatine (CRE). Six monkeys (NL) had undergone surgical ablation of MTL structures within 3 weeks of birth, six monkeys received the same lesion at approximately 5 years of age and six monkeys were normal controls. We found significant bilateral reductions of NAA relative signals exclusively in the PFC of the NL group in comparison with either of the other groups. Our results indicate that neonatal MTL damage specifically affects PFC neurons of adult monkeys as indicated by a reduction of NAA. The basis of this effect involves developmental processes as implicated by two arguments: analogous damage during adulthood does not have the same effect; NAA in the healthy brain increases during development. This finding may have implications for understanding developmental aspects of prefrontal- temporolimbic connectivity, and the reduction of NAA levels observed in prefrontal cortex of patients with schizophrenia.      

Neonatal ovarian cysts: sonographic-pathologic correlation

The authors reviewed the prenatal (11 infants) and postnatal (17 infants) sonograms and the clinical, surgical, and pathologic findings in 17 infants with an ovarian cyst to determine the sonographic features and natural history of neonatal ovarian cysts. An uncomplicated cyst (nontwisted, nonhemorrhagic) was completely anechoic and the cyst wall was imperceptible with sonography (five cases). A twisted or hemorrhagic cyst was cystic with a fluid-debris level, cystic with a retracting clot, septated with or without internal echoes, or solid (12 cases). These complicated cysts contained liquid and/or organized hematoma. Eleven of the 12 complicated cysts had a thin, highly echogenic wall. Cyst torsion commonly occurred in utero and could be diagnosed on prenatal sonograms by a typical sonographic appearance (eight cases). All of these infants were asymptomatic after birth. Four infants with hemorrhagic or twisted cysts were symptomatic. All cysts except one that resolved spontaneously were treated surgically, including three twisted cysts that showed no change in size over a 1-8-month interval. All of the cysts were of follicular origin.     

Cerebral Erdheim-Chester disease: persistent enhancement with Gd-DTPA on MR images

A case of Erdheim-Chester disease with intracerebral masses containing characteristic lipid-laden histiocytes is presented. These unusual lesions remained enhanced on magnetic resonance images obtained 8 days after injection of gadolinium diethylenetriaminepentaacetic acid (DTPA) dimeglumine. Chemical analysis of a biopsy specimen revealed a high concentration of gadolinium. Findings suggest that the Gd-DTPA complex or possibly a gadolinium-containing metabolite may be retained for extended periods in this unusual type of histiocytic lesion.     

Lethal fetal anomalies: sonographic demonstration

Sonographic demonstration of a lethal fetal anomaly may dramatically alter obstetrical management. For example, cesarean section for fetal distress may not be performed if it is known that the fetus will not survive outside the uterus. The author describes the common fetal anomalies that are predictably fatal.