Owl monkeys were inoculated intracerebrally, subcutaneously, and intravenously with JC, BK, or SV40 virus. Two of four adult owl monkeys inoculated with JC virus, a human polyomavirus, developed brain tumors at 16 and 25 months after inoculation, respectively. A grade 3 to grade 4 astrocytoma (resembling a human glioblastoma multiforme) was found in the left cerebral hemisphere and brainstem of one monkey. The second monkey developed a malignant tumor in the left cerebral hemisphere containing both glial and neuronal cell types. Impression smears prepared from unfixed tissue of this tumor showed cells that contained polyomavirus T antigen. Virion antigens were not detected. Tumor cells cultured in vitro also contained T antigen but were negative for virion antigen. Infectious virus was not isolated from extracts of this tumor.

Pediatr. Pregnant rhesus monkeys (Mucacu mulutta) at 67 to 85%' of term pregnancy were treated with betamethasone for 3 days and then delivered by cesarean section. These treated fetuses had larger lung volumes (32.6 + 1.8 ml/kg of body weight) compared to gestational age-matched controls (22.9 + 3.2 ml/kg of body weight: P < 0.025) but no alterations in surfactant properties a s measured by amniotic fluid L/S ratios, alveolar deflation stability, or lung pbosphatidylcholine. These findings suggest that betamethasone effects an increase in fetal lung volume by some method other than alteration in alveolar surfactant concentrations. Results also demonstrated an 11% increase in the collagen to elastin concentration in the treated fetuses as compared to the control animals ( P < 0.01). suggesting alterations in lung connective tissue. Morphometric studies done on the air-fixed inflated lung demonstrated a decrease in the number of alveoli Der unit volume of lung among the treated animals (0.95 + 0.07 x 10') compared to the control animals (1.19 + 0.08 x 10" P < 0.025) and a reduction in the mean surface area of the lungs of the treated animals (506 + 10 cm2 per cm3) compared to the control animals (561 + 9 cm>er cm" P < 0.005). These findings suggest that at least part of the increased maximal lung volumes is related to increased alveolar distensibility. Together, these pressure volume findings, biochemical studies, and morphometric analyses indicate that a major effect of betamethasone on the rhesus fetal lung is to alter lung connective tissue characteristics. Alterations in lung surfactant appear to be of less functional significance in this rhesus fetal model. The disparity between these findings and other animal studies might be due to differences in species, the preparation, or the method of glucocorticoid administration.1) alveolar m o r p h o m e t r y l u n g SpeculationMaternal betamethasone treatment produces alterations in the connective tissue properties of the developing fetal lung, which could have long-lasting effects on lung mechanical properties.Acceleration of fetal lung development by antenatal administration of glucocorticoids has been demonstrated in a number of clinical and animal studies (2). Most previous studies suggest that glucocorticoids act by accelerating the synthesis and release of fetal lung surfactant (2). However, we have observed that the major effect of betamethasone on fetal rhesus lung is to increase the total lung capacity, with less significant surfactant alterations (14. 15). In a more recent study, we compared air and saline fluidfilling characteristics in control and betamethasone-treated rhesus fetuses (21). Increased lung volumes were observed in the steroidtreated fetuses, both during air and saline filling. This latter observation supports our hypothesis that the functional effects of rather than upon albeolar surfactant.In this animal model, betamethasone appears to accelerate lung maturity by inducing structural changes that increase total lung volume. The questi...

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