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.     

Activity of Pilomotor Muscles of Single Tactile Hairs in the Cat

Contractions of the pilomotor muscles of individual carpal tactile sinus hairs in the cat were studied by simultaneous recording of the movement of a single hair by means of a capacitance meter, and of the electrical activity during the muscle contraction, as recorded by an external metal microelectrode. Single shock stimulation of the nerve gave rise to a twitch contraction, whereas repetitive stimulation caused summation of contractions at frequencies higher than 0.2/sec and fusion at frequencies of 1/sec or more. The electrical response consisted of a slow potential and a superimposed spike. These components were both shown to be dependent on the stimulus strength and to be facilitated on repetitive stimulation. At stimulus frequencies higher than 3/sec the spike gradually declined in amplitude and was substituted by a rhythmic oscillation at the same rate as the stimulus. Even when no spike was recorded the contraction was sustained. Comparisons are made between the electrical activity elicited in the pilomotor muscles and the junction potentials and spikes recorded in other types of smooth muscle.     

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.     

Spectral signature and heterodyne efficiency for different wavelengths in laser Doppler flowmetry

Laser Doppler perfusion monitoring and imaging technologies generate time traces and two-dimensional flow maps of the microcirculation. With the goal of reaching different tissue depths, these technologies are equipped with lassers operating at different wavelengths λ. The fact that the average scattering angle, at a single scattering event, between a photon and a red blood cell increases with λ is compensated for by a 1/λ effect in the scattering vector, rendering the average frequency shift virtually independent of the choice of wavelength. Monte Carlo simulations showed that the corresponding spectral signature of the Doppler signals for λ=632.8nm and 780nm were close to identical. The theoretical predictions were verified by calculating the centre-of-gravity (COG) frequency of the laser Doppler power spectral density for the two wavelengths from forearm and finger skin, representing a low and high perfusion area, respectively (forearm COG=123 against 121Hz, finger COG=220 against 212 Hz). When the wavelength changes from 632.8nm to 780nm, the heterodyne efficiency of the detector and, thereby, the inherent system amplifcation increase. For tissues with identical microvascular flow conditions, the output signal therfore tends to increase in magnitude when shifting to longer wavelengths.     

Neutrophilic granulocytes are the predominant cell type infiltrating pancreatic islets in contact with ABO-compatible blood

The poor outcome of intraportal islet transplantation may be explained by the instant blood-mediated inflammatory reaction (IBMIR), characterized by islet entrapment in blood clots, leucocyte infiltration and disruption of islet morphology. Here we employ a newly developed in vitro system to identify the blood cells involved in this process. Islets were mixed with ABO-compatible blood in heparinized tubes and incubated for various times up to 6 h. Clots were analysed immunohistochemically for detection of platelets (CD41a), leucocytes/lymphocytes (CD11b), granulocytes (CD16, lysozyme), neutrophilic granulocytes (neutrophil elastase), eosinophilic granulocytes (NaCN + H(2)O(2)), macrophages (CD68), dendritic cells (CD209/DC-SIGN), B cells (CD20) and T cells (CD4, CD8). Platelets were rapidly deposited around the islets in contact with the blood, reaching a maximum by 30 min. The first neutrophilic granulocytes appeared in the islets after 15 min, increased at 1 h and peaked at 2 h. Small numbers of macrophages were found infiltrating the islets already after 5 min, with a slight increase over time. However, control stainings of cultured islets and pancreas biopsies identified these cells as being largely of donor origin. No T cells, B cells, dendritic cells or eosinophilic granulocytes were detected during the 6 h observation time. Neutrophilic granulocytes were identified as the main infiltrating blood cell in islets exposed to blood, implying that these cells play a key role in clinical islet transplantation. Because islets are known to be exquisitely susceptible to oxidative stress, development of drugs targeting neutrophilic cytotoxicity could markedly improve the outcome of islet transplantation.     

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.     

Intrahippocampal grafts of fetal basal forebrain tissue alter place fields in the hippocampus of rats with fimbria-fornix lesions

Intrahippocampal grafts of fetal basal forebrain tissue have been shown to restore several aspects of neural function, including some degree of behavioral recovery in spatial memory tasks, in rats with fimbria-fornix lesions. Place fields, the behavioral correlates of complex-spike unit activity recorded in the hippocampus of rats, are altered by fimbria-fornix lesions, and provide an important measure of the functioning circuitry of the hippocampus after grafts. To investigate the effects of grafts on hippocampal circuitry, complex-spike units were recorded while the rats traversed a radial maze. Quantitative analyses of spatial activity showed that units in normal rats had spatially clustered, reliable place fields that were stable despite alterations of the maze. In contrast, units in rats with fimbria-fornix lesions had more dispersed, less reliable place fields that were disrupted when the maze was covered or rotated. Compared to rats with fimbria-fornix lesions, rats with grafts and units with more tightly clustered, more reliable, and more stable place fields when the maze was altered. The results suggest that: (1) fimbria-fornix lesions disrupt some aspects of complex-spike place field activity; (2) the functioning of hippocampal circuitry is influenced by fetal basal forebrain grafts; and (3) the grafts may ameliorate the effects of lesions on spatial behaviors by influencing critical aspects of place field activity in the hippocampus.     

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.