A functionally active complement system is present in uterine secretion of the mouse prior to implantation.

Sephadex beads were placed carefully in the uterus on days 2 and 3 and left for 6 to 8 h to absorb uterine secretion. The beads were then removed with volatile silicon oil and mounted on small pieces of nitrocellulose paper. Immuno-staining of these bead blots showed they contained the complement components C1q, C3, C4, and C5. We demonstrated that complement component C3 in the uterine secretion could be activated and deposited on model immune complexes, and also that antibody-coated erythrocytes were lysed in utero, that is, a membrane attack complex was produced. Thus, the mouse uterine secretion at the preimplantation stage contains a functionally active complement system.     

Comparative dosimetry of diode and diamond detectors in electron beams for intraoperative radiation therapy

The aim of the present study is to examine the validity of using silicon semiconductor detectors in degraded electron beams with a broad energy spectrum and a wide angular distribution. A comparison is made with diamond detector measurements, which is the dosimeter considered to give the best results provided that dose rate effects are corrected for. Two-dimensional relative absorbed dose distributions in electron beams (6-20 MeV) for intraoperative radiation therapy (IORT) are measured in a water phantom. To quantify deviations between the detectors, a dose comparison tool that simultaneously examines the dose difference and distance to agreement (DTA) is used to evaluate the results in low- and high-dose gradient regions, respectively. Uncertainties of the experimental measurement setup (+/- 1% and +/- 0.5 mm) are taken into account by calculating a composite distribution that fails this dose-difference and DTA acceptance limit. Thus, the resulting area of disagreement should be related to differences in detector performance. The dose distributions obtained with the diode are generally in very good agreement with diamond detector measurements. The buildup region and the dose falloff region show good agreement with increasing electron energy, while the region outside the radiation field close to the water surface shows an increased difference with energy. The small discrepancies in the composite distributions are due to several factors: (a) variation of the silicon-to-water collision stopping-power ratio with electron energy, (b) a more pronounced directional dependence for diodes than for diamonds, and (c) variation of the electron fluence perturbation correction factor with depth. For all investigated treatment cones and energies, the deviation is within dose-difference and DTA acceptance criteria of +/- 3% and +/- 1 mm, respectively. Therefore, p-type silicon diodes are well suited, in the sense that they give results in close agreement with diamond detectors, for practical measurements of relative absorbed dose distributions in degraded electron beams used for IORT.     

Confounding factors in HLA-DW 2 typing of human leucocytes.

Three healthy HLA-B7 homozygous subjects were found with similar but not identical HLA-D antigens; one was DW 2 homozygous according to independent typing results. This could be an expression of "long" and "short" HLA-D antigens or be due to differences in weak antigens outside the HLA-D region. Two further healthy HLA-B7 homozygous subjects were studied; one was apparently heterozygous for DW 2, the other apparently carried no DW 2 antigen. Both could discriminate between different DW 2 homozygous test cells. Two such test cells--one from a patient with multiple sclerosis (MS) and the other from a man with two children with MS--gave variable and absurb reactions with cells from the two subjects in question. It is tentatively suggested that genes exist which, when present in both moities in a mixed leucocyte reaction (MLR), can impair the MLR and give false "typing" reactions. This might be more common among patients with MS and perhaps also some other diseases (certain arthritides, e.g. rheumatoid arthritis) than among healthy subjects and can complicate or make impossible the interpretation of HLA-D typing data. It could also explain the previously-described impaired MLR between cells from patients with these diseases.     

Synthesis and secretion of IgE by an established human myeloma cell line

The rate of IgE production in vitro and the cell population proliferation rate by the established human myeloma line 266 Bl have been studied quantitatively under various tissue culture conditions. The rate of extracellular IgE accumulation depended on the type of medium used, the cell density and the period of time elapsed after explantation. The maximum production rate of 8·1 × 10⁻¹² g IgE/cell/48 hr was noticed at cell densities <10⁶/30 ml and with the presence of feeder human skin fibroblasts or glia-like cells or with the use of conditioned media harvested from such cells. The rate of cell proliferation and secretion of IgE to the medium ran parallel suggesting that the IgE production is highest when cells are in the best physiological condition. During more than one year the rate of synthesis of IgE remained stable. This functionally stable human myeloma line is suitable for further studies on immunoglobulin biosynthesis at the cellular and subcellular level under the tissue culture conditions found optimal in this study.     

Use of antisera to the isolated alpha and beta subunits of C3 as probes to study functional sites present on particle-bound C3b but absent on native soluble forms of C3

The effect of antisera to the isolated alpha and beta chains of C3 on certain C3b-dependent reactions has been studied. C5-mediated haemolysis of EAC1423b was inhibited preferentially by antiserum to the alpha chain, whereas antiserum to the beta chain inhibited the formation of C3bBb. The anti-beta chain antiserum also stabilised C3bBbP, and rendered the enzyme relatively resistant to accelerated decay in the presence of factor H. These and previous findings that anti-alpha and anti-beta IgG bind to restricted subsets of antigenic determinants on C3/C3b suggest that these antisera affect C3b function through the binding of antibodies to active binding sites exclusively exposed by bound C3b. The anti-alpha and anti-beta antibody probes are currently being further developed to verify this interpretation.     

Release of histamine in whole blood by oxygen radicals: Division between specific and unspecific processes

Oxygen derived free radicals are involved in many pathological processes such as postischemic reperfusion injuries, hepatotoxicity of drugs and inflammatory processes. Thereby these oxygen radicals induce lipid peroxidation and perturbation of cellular membranes. The aim of our present study was to determine whether oxygen radicals generated by the xanthine oxidase/hypoxanthine system cause a release of histamine in human blood cell cultures. Stimulation of blood cell cultures with oxygen radicals induced a histamine liberation which was mainly due to calcium independent processes during the first 30 min, whereas then calcium requiring processes took part in the release of histamine. The regulation of the leukocyte selectin LECAM-1 was altered by oxygen radicals whereas histamine, which is known to modulate vascular selectin expression, did not affect the expression of LECAM-1. Our data indicate that oxygen radicals induce a direct calcium independent release of histamine which is due to membrane pertubating processes during the first phase but also induce a specific reaction leading to a further indirect histamine liberation which is probably mediated by PAF.accepted by W. LorenzThe first two authors contributed equally to this paper.     

The alpha rhythm in the electroencephalogram: A theory based on a neurophysiological model

A column in the cerebral cortex is made up of a group of neurons and is considered to be a functional unit. Previous work has suggested that a column has two separate levels of activity, and that only a few of the columns are at the high level of activity simultaneously. To keep this number within proper limits, it is necessary to have a regulating system that reduces the cortical excitability when the number tends to increase, and vice versa. In the present paper, it is proposed that these changes up and down in the excitability can explain the generation of the alpha rhythm in the electroencephalogram. Preliminary results show that a normal alpha rhythm of about 10 Hz can be generated when the number of columns with high activity is shifting between four and five. The duration of the high activity of a column is around 450 ms.     

A novel two colour ELISPOT assay. I. Simultaneous detection of distinct types of antibody-secreting cells

A novel assay system has been developed which is based on the ELISPOT methodology and employs a combination of two immunoenzyme visualization systems yielding distinct colour products. This variation permits the simultaneous enumeration of two different types of cell secreting antigenically distinct products. Optimal conditions for the concurrent detection of human mononuclear cells secreting IgG or IgA antibodies are described.     

Reverse enzyme-linked immunospot assay (RELISPOT) for the detection of cells secreting immunoreactive substances

A reverse modification of the recently described enzyme-linked immunospot assay (ELISPOT), based on localized enzyme-substrate reactions in gel, is described for the enumeration of antigen-secreting cells using petri dishes coated with specific antibodies. As a model the detection of mouse and human immunoglobulin-secreting cells has been evaluated. Simple and sensitive, this new method, termed RELISPOT, can be adapted for the quantitation of secreted antigen thus providing additional information on the metabolic state of the population of cells tested.