Anti-DNA Plaque-Forming Cells (PFC) and Rosette-Forming Cells (RFC) in Spleens of NZB/W F1 Female (B/W) Mice

NZB female × NZW male F1 hybrid (B/W) mice spontaneously develop an autoimmune disease similar to human systemic lupus erythematosus (SLE)4 characterized by the appearance of antinuclear antibodies and fatal glomerulonephritis (1). Although a variety of autoantigens may be involved, anti-DNA has been strongly implicated in the pathogenesis of the renal disease (2, 3). The detectable anti-DNA in the serum is directed predominantly to determinants on single stranded DNA (4, 5).

One of the critical questions with respect to autoimmune diseases in general is whether lymphoid cell function is normal, or if in fact there is altered function of thymic dependent (T) or thymic independent (B) lymphocytes. Although other investigators have approached this problem by examining the cellular response to heterologous antigens in the B/W mouse, similar approaches to autoantigens have not been reported. The present study describes preliminary experiments which demonstrate that the spontaneously occurring immune response to single stranded deoxyribonucleic acid (S-DNA) in B/W mice can be readily detected and quantitated by the hemolytic plaque assay.

Postoperative wound infection: a computer analysis

Data believed to relate to the aetiology of postoperative wound infection were subjected to a computer analysis. Information was obtained from a total of 1000 patients and a multiple linear-regression analysis carried out. Five factors were found to be highly significant in determining the development of wound sepsis. These were a potentially dirty type of procedure, the presence of bacteria in the wound at the end of operation, one of the ward environments studied, the age of the patient, and the duration of the operation.

Growth response of Nitrosomonas europaea to amino acids

Growth responses of Nitrosomonas europaea to individual amino acids or vitamins was observed in log-phase cultures, as was the incorporation of carbon-14 labeled amino acids. Nitrite formation and protein synthesis were increased by l-glutamic acid, l-aspartic acid, l-serine, and l-glutamine. l-Lysine, l-histidine, l-threonine, l-valine, l-methionine, and l-arginine were inhibitory. The other amino acids had no effect on growth. All of the uniformly labeled amino acids added at low concentrations were taken up by growing cells and distributed into cell fractions. From 1 to 12% of the added radioactivity was present in cells analyzed in late log phase, depending on the amino acid; glycine and l-serine caused accumulation of the label to the greatest extent, whereas l-aspartic and l-glutamic acids were among those incorporated to the least extent. Aspartic acid increased both cell protein and nitrite values, but did not alter the ratio of protein to nitrite from that found in controls.

Uptake and utilization of amino acids by resting cells of Nitrosomonas europaea

Incorporation of selected amino acids by resting cells was studied with regard to effects of concentration, rate and extent of incorporation, cellular distribution, effect of ammonium ion on uptake, and competitive effects. l-Aspartic acid, l-alanine, l-serine, and glycine presented at trace levels were incorporated at rates ranging from 0.11 to 8.2 mumumoles per mg (dry weight) per minute, and maximal incorporation was 11 to 333 mumumoles per mg (dry weight). When glycine and aspartic acid were supplied at substrate level, the rate of incorporation increased 14- and 109-fold, respectively. The presence of ammonium ion further increased both the rate and extent of uptake of glycine and aspartic acid. The distribution of cellular radioactivity arising from (14)C amino acids indicated that cell pool radioactivity was concentrated from 1.2- to 24.5-fold over the external medium. Aspartic acid pool radioactivity accounted for 50% or more of the total cellular radioactivity, whereas radioactivity in glycine and serine pools dropped from initially high levels to 20 to 25% during incubation. The decrease in pool radioactivity with both glycine and serine was accompanied by an increase in other fractions, especially in the cell residue. The growth-inhibiting amino acid l-valine, supplied at substrate level, contributed more carbon per milligram (dry weight) than any other amino acid studied. l-Leucine, in the presence of l-valine, was observed to decrease valine incorporation.