Is prostaglandin E the neural mediator of the febrile response? The case against a proven obligatory role.

We have reviewed the evidence in favor of a prostaglandin mediator of the thermal responses in fever and found that PGE injected into the hypothalamus does not always cause fever, that cerebrospinal fluid concentrations of PGE are not reliable reflections of hypothalamic events, and that antipyretic drugs may act in ways other than inhibiting PGE synthesis. Fever is not blocked by prostaglandin antagonists, nor by ablation of PGE-sensitive areas of the brain. There is poor correlation between the effects of pyrogens and of PGE on cerebral neurons. There is evidence that at least one prostanoid other than prostaglandin is a mediator of fever, but the prostanoid has not been identified yet. We conclude that PGE may contribute to the neural responses in fever but is not essential.     

A method for the harvest,culture, and characterization of human adult atrial myocardial cells: Correlation with age of donor

Summary Myocardial cell culture methods are now well established for animal and fetal human tissue. We present here a method for harvesting and culturing adult human atrial myocardiocytes. Cells are obtained from fresh atrial tissue normally discarded after being removed to cannulate the right atrium during open heart surgery. The atrial tissue is minced and then digested using collagenase. The single cell suspension is initially cultured in serum-containing growth medium, then transferred to defined medium, selective for myocardial cell growth. The cells are characterized by immunoperoxidase stains and transmission electron microscopy. The cultured cells stain positive for myoglobin, whereas control cultured fibroblasts and endothelial cells do not. Electron microscopy shows the presence of numerous myofibrils, Z-bodies, pleomorphic mitochondria, and secretory granules. The chronological age of the donor was an important factor in culturing the adult tissue, the younger tissue correlated with a higher success rate. This method provides a means for in vitro study of human adult myocardial cells and provides guidelines for appropriate atrial tissue to use.     

Microzooplankton and macrozooplankton glutamate dehydrogenase as indices of the relative contribution of these fractions to ammonium regeneration in the Gulf of Maine

Ammonium regeneration by micro- (35–153 µm) andmacrozooplankton (> 153 µm) was determined in the Gulfof Maine by measuring the activity of the excretory enzyme glutamatedehydrogenase (GDH) in various size fractions. GDH maxima weregenerally observed to correspond to the depth of the chlorophyllmaximum as previously reported in the Gulf of Mexico and inthe vicinity of the Nantucket Shoals. GDH activity of the microzooplanktonwas considerably lower than the macrazooplankton, suggestingthe microzooplankton made only a minor contribution (1–11%) to the total ammonium regenerated. These results were confirmedby biomass estimates made from counts of individual species.Ammonium excretion by both zooplankton fractions was estimatedto supply 5–31 % of the nitrogen requirements for primaryproduction, with an estimated 59–63% supplied by the verticaltransport of nitrate (new nitrogen) into the euphoric zone.     

Identification of a novel T cell surface disulfide-bonded dimer distinct from the alpha/beta antigen receptor

Hybridomas were prepared from the spleen of a BALB/c mouse immunized with EL-4 T lymphoma cells. One, designated A1, was found to secrete a monoclonal antibody that reacted with two T lymphoma cells of C57BL origin, EL-4 and C6VLB, but not with normal C57BL/6 splenocytes or thymocytes, C57BL/6 T cell clones, or other T or B lymphomas by complement-mediated cytotoxicity or indirect immunofluorescent staining. Monoclonal antibody (MAb) A1 precipitated a protein that migrated at 85 kD under nonreducing and 43 kD under reducing conditions. The fact that the antigen defined by MAb A1 was a disulfide-linked dimer, together with the essentially clone-specific distribution of the reactive epitope, raised the possibility that the antibody defined an epitope of the antigen receptor. However, several additional observations revealed that the antibody defined a distinct and novel T cell surface structure. MAb 124-40, previously shown to react with the antigen receptor of C6VLB cells, reacted with variants of C6VLB that failed to express the A1 epitope. Sequential immunoprecipitation indicated that MAb A1 and MAb 124-40 reacted with distinct molecular species on C6VLB cells. Endoglycosidase digestion showed that the structure reactive with MAb A1 was not derived from that reactive with MAb 124-40 by addition of N-linked oligosaccharide residues. Two-dimensional gel electrophoretic analysis of precipitates obtained from radioiodinated C6VLB cells with MAb 124-40 resolved the alpha and beta subunits of the antigen receptor. Similar analysis of precipitates obtained with MAb A1 revealed only a single basic chain under reducing conditions, although anomalous mobility suggestive of a second, more acidic chain was observed under nonreducing conditions. Two-dimensional maps of tyrosine-containing chymotryptic peptides of the proteins isolated with MAb A1 and MAb 124-40 were completely different, suggesting that the molecules shared no peptides and were distinct in primary structure. Finally, cross-linking studies performed with a cleavable reagent indicated that the A1 molecule, unlike the antigen receptor defined with MAb 124-40, was not associated with additional, T3-like structures on the surface of C6VLB cells. Although the MAb A1 was unreactive with normal cells in cytotoxicity or staining assays, a molecule of the appropriate size was immunoprecipitated in small amounts from lysates of radioiodinated normal spleen and thymus cells. These data indicate that MAb A1 defines a novel disulfide-linked T cell surface molecule distinct from the antigen receptor.     

Studies of alveolar cell morphometry and mass clearance in the rat lung following inhalation of an enriched uranium dioxide aerosol

Summary Seventy-three rats were exposed to an aerosol of enriched uranium dioxide (UO₂), giving initial lung burdens of 26 to 447 µg at 6 days post-inhalation (PI). At 7 days PI 35 of these rats were further exposed to thermalised neutrons at a fluence of 1 x 10¹² neutrons CM^–2. There was no significant difference between the two groups in the clearance rate of the UO₂ particles from the lung, up to 590 days PI. The particles cleared relatively slowly over this period with a retention halftime in the lung of 160 to 176 days.Transmission electron microscope (TEM) studies of tissue from the alveolar region at 8 days PI showed that inhalation of UO₂ particles significantly increased the sizes of macrophage and type II cells, and the number of macrophage and type I cells. There was also a significant increase in the size of lysosomal granules within the macrophages after exposure to the UO₂ particles. The exposure to UO₂, neutrons and²³⁵U fission fragments had no significant effect on any of the cells above that observed in the animals exposed to UO₂ alone.Additional rats were exposed to the same neutron fluence without prior UO₂ inhalation. The alveolar cells of neutron-only exposed rats were, in size and number, typically no different from those in the completely unexposed control rats.     

Low nanogram detection of nucleotides using fast atom bombardment-mass spectrometry

The effect of trimethylsilyl (TMS) derivatization on detection limits of mononucleotides in fast atom bombardment-mass spectrometry (FAB-MS) was examined. FAB-MS methods were developed to optimize sensitivity using adenosine 5'-monophosphate as a model compound and then applied to reference standards of two clinically important nucleotides: tricyclic nucleoside-5'-monophosphate (TCNMP) and 5-fluoro-2'-deoxyuridine-5'-monophosphate (FdUMP). The detection limit for the TMS derivative of TCNMP was 2.5-5 ng/microliters and less than 2.5 ng/microliters for FdUMP as its TMS derivative. This is greater than two orders of magnitude more sensitive than the FAB-MS analysis of the corresponding free compounds. These low detection limits for the TMS derivatives were obtained using a narrow scan range, signal averaging, detection in the negative ion mode, and 3-nitrobenzyl alcohol as the matrix. Hydrolysis of one or more of the labile TMS groups did occur, with the extent of hydrolysis being greatest in the more protic matrices.