A rat pulmonary alveolar macrophage (PAM) cell line (NR8383) was initiated in culture in the presence of a gerbil lung cell conditioned medium (GLCM), and has been propagated continuously for over 36 mo. When examined at different times throughout this in vitro period, NR8383 exhibited characteristics typical of macrophages: (a) Zymosan ingestion was seen in 90 to 98% of the cells examined; (b) Pseudomonas aeruginosa phagocytosis in 50 to 80%; (c) Nonspecific esterase activity in greater than 95%. During the first 6 mo., the PAM replicated with doubling times approximating 15 to 20 d. Throughout this period, GLCM dependence was evident. After 27 wk in vitro, NR8383 replication increased markedly, and within 2 wk, the doubling time was less than 48 h. NR8383 was readily monitored by [3H]thymidine (TdR) blastogenesis assay. In the presence of GLCM uptake of [3H]TdR was fivefold greater than in control cultures. Adherence and growth kinetics were effectively controlled by modulation of GLCM or serum content in culture medium. It was demonstrated that PAM growth factor(s) is ubiquitous, not species-specific, and under certain conditions may be derived from "endogenous" sources of persisting non-PAM populations within the parent, uncloned line NR8383. Cloned progeny remain devoid of non-PAM "feeder" cells, but retain macrophage properties, including interleukin-1 secretion, Fc receptors, and H2O2 production.

Responses of a recently developed rat alveolar macrophage cell (NR8383.1) line were compared to those of freshly derived alveolar macrophages in vitro. Marked inter- and intraspecies heterogeneity in levels of phagocytosis of unopsonized Pseudomonas aeruginosa or zymosan was noted among freshly derived alveolar macrophages from rats, rabbits, and baboons. In contrast, phagocytic responses of alveolar macrophage cell line were predictable and highly reproducible. Similar results were obtained in measuring oxidative burst, as indicated by the production of H2O2 and luminol-enhanced chemiluminescence. Responses were again highly variable in freshly derived alveolar macrophages stimulated with zymosan or phorbol myristic acetate; moreover, freshly derived alveolar macrophages exhibited a wide range of chemiluminescence activity in unstimulated cultures. Results strongly suggest that data derived from the continuous alveolar macrophage culture NR8383.1 can be extrapolated to freshly derived alveolar macrophages of various species, and in many experiments will be useful in avoiding the significant animal-to-animal variance observed among freshly derived cell preparations.

The prevalence of Chlamydia trachomatis, a sexually transmitted disease, and the association of selected behavioral risk factors were assessed in a population of adolescents in two juvenile detention facilities. Urine was collected for Chlamydia testing and a brief interview conducted for risk and demographic information. Almost all of the 200 participants were sexually active, many before the age of 13 years. The prevalence of Chlamydia infection was 22.2% among female and 8.7% among male participants. Injection drug use was the only statistically significant variable associated with infection. Education and community services are necessary to break the cycle of infection for this high-risk population.

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Poor, urban, and immigrant populations are at far greater risk for lead exposure than are other groups in the United States. Children with even slightly elevated blood lead levels are at increased risk for significant neurobehavioral problems that can extend through adolescence. Research has shown that elevated blood lead levels in pregnant women, even those well below 10 micrograms per deciliter-the Centers for Disease Control and Prevention's "level of concern"-can cause miscarriage, premature birth, low birth weight, and subsequent developmental delays in their children. Despite these well-established dangers, routine prenatal lead screening and lead education is not a standard of care. Part 1 of this two-part article presents a short case example of a pregnant mother with lead poisoning and describes the epidemiology of lead exposure in the United States, the main sources of lead exposure, and the effects of lead on the pregnant mother and the developing fetus and child. Prevention is crucial. Treatment options such as chelation must be used selectively and will not reverse damage once it's occurred. Part 2 will describe recommendations for screening, education, nutrition, reducing environmental exposures, and treatment.