Lymphocytic alveolitis in a crematorium worker.

An asymptomatic cremator was found incidentally to have lymphocytic alveolitis by bronchoalveolar lavage, and the basis for this finding was investigated. No known causes of lymphocyte alveolitis including sarcoidosis, hypersensitivity pneumonitis, berylliosis, tuberculosis, or fungal diseases of the lung were found. By exclusion, therefore, exposure to formaldehyde and/or to compounds in the residual ash likely were etiologic in the development of the lymphocytic alveolitis.

Characterization of suppressor function of human alveolar macrophages for T lymphocyte responses to phytohemagglutinin: cellular selectivity, reversibility, and early events in T cell activation.

The predominant immunoregulatory activity of alveolar macrophages (AM) on T lymphocytes is to suppress their responses to antigenic and mitogenic stimuli. The suppressive activity of human AM for T cell responses to phytohemagglutinin (PHA) was further characterized. At ratios of AM to T lymphocytes of 0.4:1 to 1.6:1, AM inhibited the blastogenic response (3H-thymidine uptake into DNA) to PHA by 26 to 87%, respectively. Blood monocytes precultured in vitro for 5 to 7 days inhibited responses to PHA similarly. Freshly isolated blood monocytes, peritoneal macrophages, and A-549 epithelial and CCD-18Lu fibroblast cell lines failed to inhibit T lymphocyte responses. AM were capable of suppressing PHA-induced blastogenesis of purified CD4 cells without the addition of other cells. Cell contact was required for suppression of CD4 cells, as demonstrated using dual chambers. T cells precultured with AM with or without PHA retained the ability to respond to PHA compared with control T cells not precultured with AM. Kinetic experiments showed that AM needed to be added at the initiation of a 3-day culture period for suppression to occur. Analysis of the T cell DNA cycle revealed that AM decreased the percentage of cells entering the synthesis phase of DNA production. Flow cytometry also was used to assess the effect of AM on early markers of T cell activation. AM inhibited the percentage of T cells expressing the interleukin-2 receptor 46 to 83% and the transferrin receptor 58 to 78% at 24 to 48 h after stimulation with PHA. There was no effect of AM on expression of HLA-DR.(ABSTRACT TRUNCATED AT 250 WORDS)

The central origin of efferent pathways in the carotid sinus nerve of the cat.

The application of horseradish peroxidase to the central cut end of the carotid sinus nerve of the cat produced retrograde labeling of neurons in the ipsilateral medulla in the region of the nucleus ambiguus at anterior-posterior coordinates -8 to -10.5. These data coupled with previous electrophysiological observations suggest that the nucleus ambiguus may be the origin of an efferent inhibitory pathway to the carotid body.

Horseradish peroxidase tracing of visceral efferent and primary afferent pathways in the cat's sacral spinal cord using benzidine processing.

Sacral afferent and preganglionic efferent neurons were labelled by applying horseradish peroxidase (HRP) to the central end of the transected pelvic nerve. Preganglionic cells were evident as a narrow band of cells extending from the intermediolateral region dorsomedially beneath the dorsal horn. Their dendrites were located primarily within the nucleus but also projected into the dorsolateral funiculus, along the lateral edge of the dorsal horn and to dorsal commissure. Labelled primary afferent axons and/or terminals were detected in Lissauer's tract and in the marginal zone of the dorsal horn extending from the apex ventrally along its lateral edge into the dorsal region of the autonomic nucleus. These observations suggest that sacral preganglionic neurons may receive monosynaptic connections from pelvic nerve afferents.