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Two immunoglobulin-producing lines of normal lymphoblastoid cells have been established from cultures of two human astrycytomata. These had the same characteristics as lymphoblastoid lines derived from normal human lymphoid tissue or peripheral blood. It is concluded that the lymphoblastoid lines are derivates of non-neoplastic lymphoid cells (perhaps of the B series), which were present as an infiltrate within the astrocytomata. Furthermore, the slow emergence of the lymphoblastoid cells in culture, their continuing requirement for feeder cells and their production of monoclonal rather that heteroclonal immunoglobulin are attributed to an artefact of growth conditions.

Circulating testosterone concentrations in infants measured by a direct chemiluminescent immunoassay (Bayer ADVIA Centaur) were compared with those measured by a traditional radioimmunoassay using solvent extraction. The results confirm that neonatal circulating testosterone concentrations are method dependent, and each laboratory should establish method related reference ranges especially if using a direct commercial immunoassay. The results indicate that the Bayer ADVIA Centaur procedure can be used reliably in neonates. Expected values for male and female infants < 10 days old were 2.5-11.1 (n = 36) and 1.7-5.6 (n = 36) nmol/l respectively. For older neonates (10-50 days) the ranges were 0.2-17.2 (n = 42) and 0.1-1.5 (n = 7) nmol/l respectively.

Summary A model system for the comparative study of human astrocytes before and after infection with the encephalomyelitic virus of sheep, visna virus, is described. The emergence of a variant of visna virus and the modifications induced in affected cultures are discussed.

Adenyl cyclase, cyclic nucleotide phosphodiesterase and cyclic nucleotide-dependent protein kinase are present at easily measured levels in a human malignant glial cell line and distribute in subcellular fractions in a manner similar to that found for these enzymes from other mammalian tissues. The specific activity of adenyl cyclase in homogenates of the astrocytoma cells is as high as that found in homogenates of rat and human cerebral cortex. Phosphodiesterase activity measured at various concentrations of cyclic AMP could be attributed to an enzyme with an apparent Km value of 15 μM. Cyclic AMP increased protein kinase activity of cell extracts 2-fold with casein as substrate and 4-fold with calf-thymus histone as substrate. The Km for cyclic AMP stimulation was 3–5 × 10 −8 M with either substrate. The level of cyclic AMP in 1181N1 astrocytoma cells (10 pmoles/mg protein) is similar to values observed in most mammalian tissues. These results suggest that cyclic AMP in the brain may be involved in the regulation of the function of glial cells as well as neurons.

X-ray fluorescence spectroscopy provides an accurate method for quantitating trace amounts of heavy elements. In the reported case, this technic permitted the identification of deposits present in a periapical mass associated with a canine tooth as silver.

VISNA, a medium-sized RNA virus, is comparable in mode of maturation and a number of other properties with the RNA tumour viruses1,2. The virion also carries RNA-dependent DNA polymerase3–5. This enzyme was first discovered in RNA tumour viruses and thought perhaps unique to them6–9; but it was subsequently found in a very few other RNA viruses3,10, where tumorigenicity was not a known attribute. The question whether RNA-dependent DNA polymerase is a hallmark of malignancy therefore remains entirely open.

A study was undertaken to seek fine structural differences between normal and maglinant astrocytes and normal fibroblasts in cell culture. A series of human adult normal astrocytes and malignant astrocytes (including RSV-transformed cells) whose cultural characteristics had previously been reported formed the basis of the study. Also included were matched normal human fetal fibroblasts and astrocytes (from the same fetus) and methylcholanthrene-induced murine malignant astrocytes. Pellets of cells scraped from their culture vessel and sectioned as well as in situ preparations were examined. The fibroblasts were the only cells whose external microfibrils were collagenase-sensitive and considered to be tropocollagen. Both the benign and the malignant astrocytes had intracytoplasmic microfibril bands (gliofibrils) and some had external collagenase-resistant microfibrils. Malignant astrocytes had a much more developed membrane system (used in its widest sense) than normal astrocytes, had many free ribosomes and some had morphologically abnormal mitochondria. Virus was seen only in the murine malignant astrocytes, was abundant and of the murine leukemia virus group. Areas interpreted as representing fusion in progress were seen at the surface of some RSV-transfomed giant tumor astrocytes. The fine structure of one cell type from an IgG-producing culture from human glioblastoma corresponded with that reported for immunocytes.

A Review of Related Laboratory Expenditures Over a Period of 18 Months.— Since February 1963, 28 renal transplants, 3 liver transplants, 1 and 4 splenic transplants, 2 have been performed on patients at Denver Veterans Administration Hospital. With the increasing sophistication of the associated surgery, and the progressive understanding of their postsurgical management, the expansion of organ transplant programs to many other centers seems likely. This paper is a presentation of the costs involved in the running of the transplant program for an 18-month period, from July 1963 through December 1964. It is felt that this will give a greater understanding of the tremendous expense involved in such an undertaking. This includes the inpatient and continual outpatient care. The schedule of charges adopted by the Denver VA laboratory (Table 1) follows that suggested by the Colorado General Hospital Laboratory. These charges are estimated to cover only the cost of the