Automation of etch pit analyses on solid-state nuclear track detectors with machine learning for laser-driven ion acceleration

Solid-state nuclear track detectors (SSNTDs) are often used as ion detectors in laser-driven ion acceleration experiments and are considered to be the most reliable ion diagnostics since they are sensitive only to ions and measure ions one by one. However, ion pit analyses require tremendous time and effort in chemical etching, microscope scanning, and ion pit identification by eyes. From a laser-driven ion acceleration experiment, there are typically millions of microscopic images, and it is practically impossible to analyze all of them by hand. This research aims to improve the efficiency and automation of SSNTD analyses for laser-driven ion acceleration. We use two sets of data obtained from calibration experiments with a conventional accelerator where ions with known nuclides and energies are generated and from actual laser experiments using SSNTDs. After chemical etching and scanning the SSNTDs with an optical microscope, we use machine learning to distinguish the ion etch pits from noises. From the results of the calibration experiment, we confirm highly accurate etch-pit detection with machine learning. We are also able to detect etch pits with machine learning from the laser-driven ion acceleration experiment, which is much noisier than calibration experiments. By using machine learning, we successfully identify ion etch pits ∼105 from more than 10 000 microscopic images with a precision of ≳95%. A million microscopic images can be examined with a recent entry-level computer within a day with high precision. Machine learning tremendously reduces the time consumption on ion etch pit analyses detected on SSNTDs.

Detection of current-sheet and bipolar ion flows in a self-generated antiparallel magnetic field of laser-produced plasmas for magnetic reconnection research

Magnetic reconnection in laser-produced magnetized plasma is investigated by using optical diagnostics. The magnetic field is generated via the Biermann battery effect, and the inversely directed magnetic field lines interact with each other. It is shown by self-emission measurement that two colliding plasmas stagnate on a midplane, forming two planar dense regions, and that they interact later in time. Laser Thomson scattering spectra are distorted in the direction of the self-generated magnetic field, indicating asymmetric ion velocity distribution and plasma acceleration. In addition, the spectra perpendicular to the magnetic field show different peak intensity, suggesting an electron current formation. These results are interpreted as magnetic field dissipation, reconnection, and outflow acceleration. Two-directional laser Thomson scattering is, as discussed here, a powerful tool for the investigation of microphysics in the reconnection region.

Mass-resolved ion measurement by particle counting analysis for characterizing relativistic ion beams driven by lasers

Particle counting analysis is a possible way to characterize GeV-scale, multi-species ions produced in laser-driven experiments. We present a multi-layered scintillation detector to differentiate multi-species ions of different masses and energies. The proposed detector concept offers potential advantages over conventional diagnostics in terms of (1) high sensitivity to GeV ions, (2) realtime analysis, and (3) the ability to differentiate ions with the same charge-to-mass ratio. A novel choice of multiple scintillators with different ion stopping powers results in a significant difference in energy deposition between the scintillators, allowing accurate particle identification in the GeV range. Here, we report a successful demonstration of particle identification for heavy ions, performed at the Heavy Ion Medical Accelerator in Chiba. In the experiment, the proposed detector setup showed the ability to differentiate particles with similar atomic numbers, such as C⁶⁺ and O⁸⁺ ions, and provided an excellent energy resolution of 0.41%-1.2% (including relativistic effect, 0.51%--1.6%).

Predictive capability of material screening by fast neutron activation analysis using laser-driven neutron sources

Bright, short-pulsed neutron beams from laser-driven neutron sources (LANSs) provide a new perspective on material screening via fast neutron activation analysis (FNAA). FNAA is a nondestructive technique for determining material elemental composition based on nuclear excitation by fast neutron bombardment and subsequent spectral analysis of prompt γ-rays emitted by the active nuclei. Our recent experiments and simulations have shown that activation analysis can be used in practice with modest neutron fluences on the order of 10⁵ n/cm², which is available with current laser technology. In addition, time-resolved γ-ray measurements combined with picosecond neutron probes from LANSs are effective in mitigating the issue of spectral interference between elements, enabling highly accurate screening of complex samples containing many elements. This paper describes the predictive capability of LANS-based activation analysis based on experimental demonstrations and spectral calculations with Monte Carlo simulations.

High-power laser experiment on developing supercritical shock propagating in homogeneously magnetized plasma of ambient gas origin

A developing supercritical collisionless shock propagating in a homogeneously magnetized plasma of ambient gas origin having higher uniformity than the previous experiments is formed by using high-power laser experiment. The ambient plasma is not contaminated by the plasma produced in the early time after the laser shot. While the observed developing shock does not have stationary downstream structure, it possesses some characteristics of a magnetized supercritical shock, which are supported by a one-dimensional full particle-in-cell simulation taking the effect of finite time of laser-target interaction into account.

Direct observations of pure electron outflow in magnetic reconnection

Magnetic reconnection is a universal process in space, astrophysical, and laboratory plasmas. It alters magnetic field topology and results in energy release to the plasma. Here we report the experimental results of a pure electron outflow in magnetic reconnection, which is not accompanied with ion flows. By controlling an applied magnetic field in a laser produced plasma, we have constructed an experiment that magnetizes the electrons but not the ions. This allows us to isolate the electron dynamics from the ions. Collective Thomson scattering measurements reveal the electron Alfvénic outflow without ion outflow. The resultant plasmoid and whistler waves are observed with the magnetic induction probe measurements. We observe the unique features of electron-scale magnetic reconnection simultaneously in laser produced plasmas, including global structures, local plasma parameters, magnetic field, and waves.

A multi-stage scintillation counter for GeV-scale multi-species ion spectroscopy in laser-driven particle acceleration experiments

Particle counting analysis (PCA) with a multi-stage scintillation detector shows a new perspective on angularly resolved spectral characterization of GeV-scale, multi-species ion beams produced by high-power lasers. The diagnosis provides a mass-dependent ion energy spectrum based on time-of-flight and pulse-height analysis of single particle events detected through repetitive experiments. With a novel arrangement of multiple scintillators with different ions stopping powers, PCA offers potential advantages over commonly used diagnostic instruments (CR-39, radiochromic films, Thomson parabola, etc.) in terms of coverage solid angle, detection efficiency for GeV-ions, and real-time analysis during the experiment. The basic detector unit was tested using 230-MeV proton beam from a synchrotron facility, where we demonstrated its potential ability to discriminate major ion species accelerated in laser-plasma experiments (i.e., protons, deuterons, carbon, and oxygen ions) with excellent energy and mass resolution. The proposed diagnostic concept would be essential for a better understanding of laser-driven particle acceleration, which paves the way toward all-optical compact accelerators for a range of applications.

High-power laser experiment forming a supercritical collisionless shock in a magnetized uniform plasma at rest

We present an experimental method to generate quasiperpendicular supercritical magnetized collisionless shocks. In our experiment, ambient nitrogen (N) plasma is at rest and well magnetized, and it has uniform mass density. The plasma is pushed by laser-driven ablation aluminum (Al) plasma. Streaked optical pyrometry and spatially resolved laser collective Thomson scattering clarify structures of plasma density and temperatures, which are compared with one-dimensional particle-in-cell simulations. It is indicated that just after the laser irradiation, the Al plasma is magnetized by a self-generated Biermann battery field, and the plasma slaps the incident N plasma. The compressed external field in the N plasma reflects N ions, leading to counterstreaming magnetized N flows. Namely, we identify the edge of the reflected N ions. Such interacting plasmas form a magnetized collisionless shock.

Energetic α-particle sources produced through proton-boron reactions by high-energy high-intensity laser beams

In an experiment performed with a high-intensity and high-energy laser system, α-particle production in proton-boron reaction by using a laser-driven proton beam was measured. α particles were observed from the front and also from the rear side, even after a 2-mm-thick boron target. The data obtained in this experiment have been analyzed using a sequence of numerical simulations. The simulations clarify the mechanisms of α-particle production and transport through the boron targets. α-particle energies observed in the experiment and in the simulation reach 10-20 MeV through energy transfer from 20-30 MeV energy incident protons. Despite the lower cross sections for protons with energy above the sub-MeV resonances in the proton-boron reactions, 10^{8}-10^{9}α particles per steradian have been detected.

Rayleigh-Taylor instability experiments on the LULI2000 laser in scaled conditions for young supernova remnants

We describe a platform developed on the LULI2000 laser facility to investigate the evolution of Rayleigh-Taylor instability (RTI) in scaled conditions relevant to young supernova remnants (SNRs) up to 200 years. An RT unstable interface is imaged with a short-pulse laser-driven (PICO2000) x-ray source, providing an unprecedented simultaneous high spatial (24μm) and temporal (10 ps) resolution. This experiment provides relevant data to compare with astrophysical codes, as observational data on the development of RTI at the early stage of the SNR expansion are missing. A comparison is also performed with FLASH radiative magnetohydrodynamic simulations.

Laboratory study of stationary accretion shock relevant to astrophysical systems

Accretion processes play a crucial role in a wide variety of astrophysical systems. Of particular interest are magnetic cataclysmic variables, where, plasma flow is directed along the star’s magnetic field lines onto its poles. A stationary shock is formed, several hundred kilometres above the stellar surface; a distance far too small to be resolved with today’s telescopes. Here, we report the results of an analogous laboratory experiment which recreates this astrophysical system. The dynamics of the laboratory system are strongly influenced by the interplay of material, thermal, magnetic and radiative effects, allowing a steady shock to form at a constant distance from a stationary obstacle. Our results demonstrate that a significant amount of plasma is ejected in the lateral direction; a phenomenon that is under-estimated in typical magnetohydrodynamic simulations and often neglected in astrophysical models. This changes the properties of the post-shock region considerably and has important implications for many astrophysical studies.

Supersonic plasma turbulence in the laboratory

The properties of supersonic, compressible plasma turbulence determine the behavior of many terrestrial and astrophysical systems. In the interstellar medium and molecular clouds, compressible turbulence plays a vital role in star formation and the evolution of our galaxy. Observations of the density and velocity power spectra in the Orion B and Perseus molecular clouds show large deviations from those predicted for incompressible turbulence. Hydrodynamic simulations attribute this to the high Mach number in the interstellar medium (ISM), although the exact details of this dependence are not well understood. Here we investigate experimentally the statistical behavior of boundary-free supersonic turbulence created by the collision of two laser-driven high-velocity turbulent plasma jets. The Mach number dependence of the slopes of the density and velocity power spectra agree with astrophysical observations, and supports the notion that the turbulence transitions from being Kolmogorov-like at low Mach number to being more Burgers-like at higher Mach numbers.

HLA class I antigens are possible prognostic factors in hepatocellular carcinoma

Thirty patients who underwent hepatectomy for the treatment of hepatocellular carcinoma (HCC) were examined for expression of HLA class I antigens on HCC cells by flow cytometry. The expression was found significantly lower in cases of stage IV compared with those of stage I or stage II (p<0.05), and in cases of intrahepatic metastases compared with those without metastases (p<0.001). In cases of non-curative hepatectomy, the expression of HLA class I antigens was lower compared with those treated by curative resection. Postoperative cumulative disease-free survival rates were well correlated with the expression rate of HLA class I antigens (p<0.05). Expression of HLA class I antigens on HCC may indicate low malignancy and better prognosis.

Optical pyrometer system for collisionless shock experiments in high-power laser-produced plasmas

A temporally and spatially resolved optical pyrometer system has been fielded on Gekko XII experiments. The system is based on the self-emission measurements with a gated optical imager (GOI) and a streaked optical pyrometer (SOP). Both detectors measure the intensity of the self-emission from laser-produced plasmas at the wavelength of 450 nm with a bandpass filter with a width of ~10 nm in FWHM. The measurements were calibrated with different methods, and both results agreed with each other within 30% as previously reported [T. Morita et al., Astrophys. Space Sci. 336, 283 (2011)]. As a tool for measuring the properties of low-density plasmas, the system is applicable for the measurements of the electron temperature and density in collisionless shock experiments [Y. Kuramitsu et al., Phys. Rev. Lett. 106, 175002 (2011)].

Kelvin-Helmholtz turbulence associated with collisionless shocks in laser produced plasmas

We report the experimental results of a turbulent electric field driven by Kelvin-Helmholtz instability associated with laser produced collisionless shock waves. By irradiating an aluminum double plane target with a high-power laser, counterstreaming plasma flows are generated. As the consequence of the two plasma interactions, two shock waves and the contact surface are excited. The shock electric field and transverse modulation of the contact surface are observed by proton radiography. Performing hydrodynamic simulations, we reproduce the time evolutions of the reverse shocks and the transverse modulation driven by Kelvin-Helmholtz instability.

Time evolution of collisionless shock in counterstreaming laser-produced plasmas

We investigated the time evolution of a strong collisionless shock in counterstreaming plasmas produced using a high-power laser pulse. The counterstreaming plasmas were generated by irradiating a CH double-plane target with the laser. In self-emission streaked optical pyrometry data, steepening of the self-emission profile as the two-plasma interaction evolved indicated shock formation. The shock thickness was less than the mean free path of the counterstreaming ions. Two-dimensional snapshots of the self-emission and shadowgrams also showed very thin shock structures. The Mach numbers estimated from the flow velocity and the brightness temperatures are very high.

Experimental evidence of nonthermal acceleration of relativistic electrons by an intensive laser pulse

Nonthermal acceleration of relativistic electrons is investigated with an intensive laser pulse. An energy distribution function of energetic particles in the universe or cosmic rays is well represented by a power-law spectrum, therefore, nonthermal acceleration is essential to understand the origin of cosmic rays. A possible candidate for the origin of cosmic rays is wakefield acceleration at relativistic astrophysical perpendicular shocks. The wakefield is considered to be excited by large-amplitude precursor light waves in the upstream of the shocks. Substituting an intensive laser pulse for the large amplitude light waves, we performed a model experiment of the shock environments in a laboratory plasma. An intensive laser pulse was propagated in a plasma tube created by imploding a hollow polystyrene cylinder, as the large amplitude light waves propagated in the upstream plasma at an astrophysical shock. Nonthermal electrons were generated, and the energy distribution functions of the electrons have a power-law component with an index of ~2. We described the detailed procedures to obtain the nonthermal components from data obtained by an electron spectrometer.

Structural and functional dissection of the cytoplasmic domain of the transmembrane adaptor protein SIT (SHP2-interacting transmembrane adaptor protein)

SIT (SHP2-interacting transmembrane adaptor protein) is a recently identified transmembrane adaptor protein, which is expressed in lymphocytes. Its structural properties, in particular the presence of five potential tyrosine phosphorylation sites, suggest involvement of SIT in TCR-mediated recruitment of SH2 domain-containing intracellular signaling molecules to the plasma membrane. Indeed, it has recently been demonstrated that SIT inducibly interacts with the SH2-containing protein tyrosine phosphatase 2 (SHP2) via an immunoreceptor tyrosine-based inhibition motif (ITIM). Moreover, SIT is capable to inhibit TCR-mediated signals proximal of activation of protein kinase C. However, inhibition of T cell activation by SIT occurs independently of SHP2 binding. The present study was performed to further characterize the molecular interaction between SIT and intracellular effector molecules and to identify the protein(s) mediating its inhibitory function. We demonstrate that SIT not only interacts with SHP2 but also with the adaptor protein Grb2 via two consensus YxN motifs. However, mutation of both Grb2-binding sites also does not influence the inhibitory function of SIT. In contrast, mutation of the tyrosine-based signaling motif Y(168) ASV completely abrogates the ability of SIT to inhibit T cell activation. Co-precipitation experiments revealed that the tyrosine kinase p50(csk) could represent the negative regulatory effector molecule that binds to this motif.

Differential expression of phosphatidylethanol-amine-binding protein in rat hepatoma cell lines: analyses of tumor necrosis factor-alpha-resistant cKDH-8/11 and -sensitive KDH-8/YK cells by two-dimensional gel electrophoresis

To determine intracellular factors influencing the sensitivity of cancer cells to tumor necrosis factor-alpha (TNF-alpha), we studied the expression of intracellular proteins in TNF-alpha-resistant cKDH-8/11 and -sensitive KDH-8/YK rat hepatoma cell lines using the technique of two-dimensional gel electrophoresis (2-DE). From the 2-DE patterns, it was demonstrated that TNF-alpha-resistant cKDH-8/11 cells had increased levels of protein of molecular weight (Mr) 22 500 and isoelectric point (pI) 5.2, compared with TNF-alpha-sensitive KDH-8/YK cells. Therefore, we excised cyanogen bromide (CNBr) fragments of proteins in the spot for N-terminal sequencing. Microsequencing for the CNBr fragments identified the protein as rat phosphatidylethanolamine-binding protein. These findings suggest that the intracellular phosphatidylethanolamine-binding protein could be one of the factors responsible for the resistance of cKDH-8/11 cells to TNF-alpha-induced cell death.

Selectivity and sensitivity in the measurement of reactive oxygen species (ROS) using chemiluminescent microspheres prepared by the binding of acridinium ester or ABEI to polymer microspheres

Two kinds of chemiluminescent microspheres were prepared as tools for measuring reactive oxygen species (ROS) released into phagosomes in phagocytizing cells, by chemically binding acridinium ester or ABEI (isoluminol derivative) to polymer microspheres, and were examined from the viewpoint of specificity and sensitivity to ROS. Acridinium ester-bound microspheres (AE-ms) were found to be a sensitive probe to superoxide anion and hydrogen peroxide under a neutral condition (pH 7.2). AE-ms emitted strong chemiluminescence (CL) by hypoxanthine (HPX)/xanthine oxidase (XOD) or hydrogen peroxide. The CL by HPX/XOD was initially inhibited by superoxide dismutase. At pH 5.6, the CL intensity from AE-ms in the presence of HPX/XOD was reduced to about one-eighth of that at pH 7.2. ABEI-bound microspheres (ABEI-ms) were found to be a selective probe for singlet oxygen although not highly sensitive. ABEI-ms emitted CL of moderate intensity with hydrogen peroxide/myeloperoxidase (MPO), but not with hydrogen peroxide alone or with hypochlorite/MPO at pH 5.6. The CL from ABEI-ms with hydrogen peroxide/MPO was completely inhibited by azide. ABEI-ms did not emit CL in the presence of HPX/XOD or by potassium superoxide at pH 5.6. The result of supplemental experiments using dissolved chemiluminescent probes and non-enzymatically generated ROS supported the above-described selectivity and sensitivity of chemiluminescent microspheres.

The suppression of metastases and the change in host immune response after low-dose total-body irradiation in tumor-bearing rats

We have shown that metastasis is suppressed by low-dose total-body irradiation (TBI) in tumor-bearing rats. We have evaluated the immunological effects of low-dose TBI. Total-body irradiation with 0.2 Gy was given 14 days after the implantation of 5 x 10(5) allogenic hepatoma cells (KDH-8) which produce transforming growth factor beta (TGF-beta). On day 21, the splenocytes and tumor-tissue infiltrating lymphocytes were analyzed by FACScan and RT-PCR for the mRNA of the genes that encode tumor necrosis factor alpha (TNF-alpha), interferon gamma (IFN-gamma), TGF-beta, interleukin (IL)-4, IL-10 and IL-6. The same procedure was conducted with untreated rats and with rats that underwent local irradiation with 0.2 Gy. The low-dose TBI significantly decreased the incidence of lung and lymph node metastasis (P < 0.01), whereas the same dose of local irradiation had no effect on the incidence of metastasis. The proportion of CD8+ cells in splenocytes increased in the low-dose TBI group (P < 0.01) compared to the locally irradiated and the untreated groups. The tumor-tissue infiltrating lymphocytes were also significantly increased after low-dose TBI (P < 0.01). The FACScan analysis revealed that 72% of the tumor-tissue infiltrating lymphocytes were CD8+. In both spleen and tumor tissue after low-dose TBI, mRNA expression of the genes that encode IFN-gamma and TNF-alpha increased, while that of the Tgfb gene decreased. There was no expression of the mRNAs of the Il4, Il6 and Il10 genes. CD8+ cells and the cytokine network may play an important role in the antitumor effect of low-dose TBI.

Rapid detection and counting of viable bacteria in vegetables and environmental water using a photon-counting TV camera

A bioluminescence assay carried out with a photon-counting TV camera was evaluated for rapid enumeration of viable bacterial counts. The test sample was filtered through a membrane filter, and the membrane filter retaining bacteria was incubated at 37 degrees C for 6 h on a filter paper soaked with nutrient broth supplemented with 0.5% NaCl. The membrane filter was then subjected to a bioluminescence reaction, and the intensity of light and numbers of light emission points on the filter were measured with a photon-counting TV camera. The light intensity measured on seven different bacteria correlated with initial viable counts; the correlation coefficient was calculated to be 0.89. The number of light emission points measured on Escherichia coli also correlated with the initial viable counts (r = 0.81) in a range from 1 to 100 CFU. Presumptive bacterial counts by the present bioluminescence assay determined on 79 samples of vegetables and 122 samples of environmental water correlated well with the viable counts obtained by the conventional plating method, with correlation coefficients of 0.87 and 0.82, respectively.

ND-2001 suppresses lung metastasis of human renal cancer cells in athymic mice

Explants of highly metastatic human renal cell carcinoma SN12Cpm6 cells in athymic mice were treated with sodium D-glucaro-delta-lactam (sodium 5-amino-5-deoxy-D-glucosaccharic acid-delta-lactam; ND-2001). ND-2001 (50 micrograms/ml) caused 78% inhibition of lung metastasis of SN12Cpm6 cells (two of five animals remaining metastasis free). The in vitro tumor cell invasion assay showed that ND-2001 (100 micrograms/ml) suppressed the invasive activity of SN12Cpm6 cells to Matrigel matrix at an inhibition rate of 72%. These results suggest that ND-2001 may be a new anti-metastatic drug against human cancer cells.

Combination therapy of active hexose correlated compound plus UFT significantly reduces the metastasis of rat mammary adenocarcinoma

Synergistic effects of active hexose correlated compound (AHCC) extracted from mushroom on the treatment with UFT against mammary adenocarcinoma, SST-2 cells, in congenitally T cell-depressed spontaneously hypertensive rats (SHR) were observed. AHCC plus UFT had slight but significant effects on the growth of primary tumors. Pulmonary metastases were not inhibited by the treatment with AHCC plus UFT, whereas metastases to axillary lymph nodes (LN) were obviously inhibited. Combination of AHCC plus UFT showed similar synergistic anti-metastatic effects in SHR rats with accelerated pulmonary metastases following the surgical removal of the primary tumors. In vitro studies demonstrated that AHCC plus UFT enhanced the NK cell activity in tumor-bearing rats, whereas UFT alone depressed the NK cell activity. AHCC plus UFT also enhanced the NO production and cytotoxicity of peritoneal macrophages. In addition, AHCC restored the suppressed mRNA expression of interleukin-1alpha and tumor necrosis factor-alpha induced by the chemotherapy. Taken together, the combination of AHCC plus UFT brought about good therapeutic effects not only on primary tumor growth but also on reducing metastasis and these effects were mediated by host immunity which was restored or activated by AHCC. AHCC may be a good candidate for a biological response modifier.

A new anti-metastatic drug, ND-2001, inhibits lung metastases in rat hepatoma cells by suppressing haptotaxis of tumor cells toward laminin

We examined the effects of ex vivo treatment of tumor cells with sodium D-glucaro-delta-lactam (sodium 5-amino-5-deoxy-D-glucosaccharic acid-delta-lactam; ND-2001). The ex vivo treatment of rat hepatoma cKDH-8/11 cells with this new synthetic product of the antibiotic nojirimycin, ND-2001 (50 microg/ml), inhibited the experimentally induced lung metastases of the tumor cells significantly at an inhibition rate of 69.2% (one of 10 animals remained metastasis free). Also, it was elucidated in in vitro tumor cell invasion assays that ND-2001 (50 microg/ml) suppressed the invasion activities of cKDH-8/11 cells to Matrigel Matrix at an inhibition rate of 69.3%. However, phagokinetic track assays revealed that ND-2001 did not suppress the random motility of cKDH-8/11 cells. However, ND-2001 (50 microg/ml) suppressed the haptotaxis, another important role in tumor invasion, of cKDH-8/11 cells toward laminin (inhibition rate of 77.0%). These results suggest that ND-2001 suppressed the haptotaxis of tumor cells toward laminin directly at the step of invading the basement membrane and brought about the inhibition of lung metastases.

Therapeutic effects of a new synthetic lipid A analog, ONO-4007, on rat hepatoma KDH-8 depend on tumor necrosis factor-sensitivity of the tumor cells

ONO-4007 is a new synthetic lipid A derivative with low endotoxic activities. ONO-4007 was effective against KDH-8, a tumor necrosis factor (TNF)-sensitive rat hepatoma cell line, but neither effective against KMT-17, a TNF-resistant rat fibrosarcoma cell line, nor SST-2, a TNF-resistant rat mammary adenocarcinoma cell line. We have established two sublines from KDH-8 to further examine the therapeutic mechanisms of ONO-4007 in vivo: TNF-sensitive KDH-8/YK and TNF-resistant cKDH-8/11. The two sublines equally proliferated in vitro. Multiple systemic i.v. administration of ONO-4007 was performed on days 7, 14 and 21 after tumor implantation. Although treatment with ONO-4007 had no effect on the growth of cKDH-8/11 in WKAH rats in vivo, 60% of KDH-8/YK-bearing rats treated with ONO-4007 survived. The administration of ONO-4007 brought about significant therapeutic effects on KDH-8/YK-bearing rats but not on cKDH-8/11-bearing rats. These results suggest that ONO-4007 is therapeutically useful for the treatment of TNF-alpha-sensitive tumors.

The mechanism of locally enhanced production of tumor necrosis factor-alpha in tumor tissues by the administration of a new synthetic lipid A analog, ONO-4007, in hepatoma-bearing rats

ONO-4007 is a new synthetic lipid A analog with low endotoxic activities. We previously found that ONO-4007 induced the production of tumor necrosis factor (TNF)-alpha in rat hepatoma KDH-8 tumor tissues and brought about the regression of transplanted KDH-8 cells. By contrast, ONO-4007 did not induce TNF-alpha production in spleens and sera 90 min after treatment. In the present study we attempted to elucidate how ONO-4007 induces TNF-alpha production in tumor tissues locally. We found that extracellular matrix including gelatin, fibronectin and Matrigel did not induce TNF-alpha production in splenocytes treated with ONO-4007 in vitro. However, splenocytes co-cultured with cKDH-8/11 tumor cells in the presence of ONO-4007 produced more TNF-alpha than splenocytes cultured by themselves in the presence of ONO-4007. The stimulation of cKDH-8/11 cells in the presence of ONO-4007 for splenocytes to produce TNF-alpha depended on the type of contact between the cells. The cKDH-8/11 cells fixed in formalin were not able to induce TNF-alpha production of splenocytes even in the presence of ONO-4007. However, syngeneic fibrosarcoma cell line KMT-17/A3, allogeneic hepatocellular carcinoma cell line LDH and rat lung endotherial cell line RLE induced TNF-alpha production in splenocytes, but their stimulation was weaker than that of cKDH-8/11. The soluble form of the cKDH-8/11 cell membrane did not stimulate splenocytes to produce TNF-alpha in the presence of ONO-4007. cKDH-8/11 cells did not stimulate the splenocytes devoid of macrophages to produce TNF-alpha in the presence of ONO-4007.

Restoration of macrophage tumoricidal activity by bleomycin correlates with the decreased production of transforming growth factor beta in rats bearing KDH-8 hepatoma cells

To explore the mechanisms of immuno-modulatory activities of bleomycin, we investigated interferon gamma (IFN gamma) mRNA expression, tumor necrosis factor alpha (TNF alpha) production, nitric oxide (NO) production and macrophage tumoricidal activities in rats bearing KDH-8 hepatoma cells, which secreted a large amount of transforming growth factor beta (TGF beta), and these processes in KDH-8 tumor-bearing rats treated with bleomycin. We found that IFN gamma mRNA expression, TNF alpha production, NO production and macrophage cytotoxic activities were lower in the KDH-8-bearing rats than in normal rats. On the other hand, low-dose bleomycin restored the macrophage cytotoxic activities, NO production, IFN gamma mRNA expression and TNF alpha production in the KDH-8-bearing rats. In vitro experiments showed that KDH-8-derived TGF beta decreased the IFN gamma mRNA expression and TNF alpha production in splenocytes, and NO production in peritoneal macrophages. These results suggest that low-dose bleomycin restored the cytokine production and macrophage tumoricidal activities in the KDH-8-bearing rats by decreasing KDH-8-derived TGF beta.

A new synthetic lipid A analog, ONO-4007, stimulates the production of tumor necrosis factor-alpha in tumor tissues, resulting in the rejection of transplanted rat hepatoma cells

ONO-4007 is a new synthetic lipid A derivative with low endotoxic activities. We have examined the therapeutic effects of ONO-4007 on rat hepatocellular carcinoma KDH-8 cells, rat fibrosarcoma KMT-17 cells and rat mammary adenocarcinoma SST-2 cells in vivo. Multiple systemic i.v. administration of ONO-4007 was performed on days 7, 14 and 21 after tumor implantation of KDH-8 and SST-2 cells, and on days 5, 10 and 15 after tumor implantation of KMT-17 cells. ONO-4007 showed significant therapeutic effects on KDH-8 cells; by the administration of ONO-4007 (2.5 mg/kg) 70% of rats were cured and by the administration of ONO-4007 (5 mg/kg) 50% of rats were cured. Furthermore, the ONO-4007 treatment prolonged the mean survival time of KDH-8-bearing rats. However, ONO-4007 had no effect on KMT-17 and SST-2 cells, and it had no direct effect on the growth of KDH-8 cells in vivo. Albeit the stimulation with ONO-4007 induced mRNA expressions of interleukin (IL)-1alpha, IL-6 and tumor necrosis factor (TNF)-a, those of IL-2, IL-4, IL-10 and interferon (IFN)-gamma were not induced. Using a bioassay, we found that the production of TNF-alpha in the tumor tissues was induced by ONO-4007 in a dose-dependent manner. KDH-8 cells were sensitive to human natural TNF-alpha in vitro. However, KMT-17 and SST-2 cells were resistant against TNF-alpha in vitro. These results suggest that ONO-4007 is therapeutically useful for the treatment of TNF-alpha-sensitive tumors.

Enhancement of lymphokine-activated killer cell activity by fibronectin

In this study, we demonstrated that immobilized fibronectin (FN) enhanced lymphokine-activated killer cell (LAK) activity, and that the enhanced LAK activity was completely abrogated by an anti-VLA-5 monoclonal antibody and RGD peptide. Fresh spleen cells expressed VLA-4, VLA-6, and vitronectin receptor, whereas VLA-5 was expressed only on the spleen cells activated with interleukin-2. LAK cells showed increased adhesion to immobilized FN compared with that to control bovine serum albumin, and the increased adhesion of LAK cells to immobilized FN was inhibited by anti-VLA-5 monoclonal antibody. Conjugate-formation assay showed that the LAK cells cultured on immobilized FN bound to target cells more efficiently than the control LAK cells, and that anti-LFA-1 monoclonal antibody inhibited the LAK-target cell binding. Immobilized type IV collagen and laminin, as well as FN, enhanced LAK activity. All of these results suggest that the interaction of integrins expressed on LAK cells with extracellular matrix proteins acts in a costimulatory manner for the enhancement of LAK activity, and that anchorage is necessary for full activation of LAK cells.

Transforming growth factor beta 1 (TGF-beta 1) produced in tumour tissue after chemotherapy acts as a lymphokine-activated killer attractant

Using an under agarose migration (UAM) assay, we studied lymphokine-activated killer (LAK)-attractant activity in cultured conditioned medium of tumour tissues after chemotherapy as a possible mechanism of enhanced LAK cell accumulation into tumour tissues after chemotherapy. BMT-11 is a fibrosarcoma developed in C57BL/6 mice. The conditioned medium of BMT-11 tumour tissues obtained from mice treated with various anti-cancer drugs had chemotactic activity for LAK cells (LAK-attractant activity). mRNA expression of interleukin (IL)-1 alpha, IL-6, IL-8, interferon (IFN)-gamma, and tumour necrosis factor (TNF)-alpha was observed in untreated tumour tissues, which were not enhanced by cyclophosphamide treatment. mRNA expression of TGF-beta 1 was not detected in untreated tumour tissues by reverse transcription-polymerase chain reaction (RT-PCR), but was detected in tumour tissues treated with cyclophosphamide. Recombinant human TGF-beta 1 showed LAK-attractant activity at a concentration of 0.1 ng ml-1 and 1 ng ml-1, whereas fresh splenocytes were not attracted by TGF-beta 1. Anti-TGF-beta 1 antibody inhibited LAK-attractant activity in the conditioned medium of tumour tissues treated with cyclophosphamide to approximately 35% that of control at 100 micrograms ml-1. These findings indicate that TGF-beta 1 produced in the tumour tissues of mice treated with anti-cancer drugs could be a LAK attractant. By a 4 h 51Cr release assay of natural killer cell-resistant BMT-11 tumour cells, we observed that TGF-beta 1 at a concentration from 0.01 ng ml-1 to 10 ng ml-1 did not inhibit LAK activity in an effector phase. Taken together, we suggest that TGF-beta 1 produced in tumour tissues after chemotherapy participates in gathering transferred LAK cells and contributes to the therapeutic effects of transferred LAK cells.

Restoration of interleukin-2 production in tumor-bearing rats through reducing tumor-derived transforming growth factor beta by treatment with bleomycin

We studied mechanisms of immunosuppression caused by tumor-derived transforming growth factor-beta (TGF beta) and restoration of the immune response by treatment with bleomycin in rats bearing KDH-8 hepatoma. Interleukin-2 (IL-2) production from splenocytes of KDH-8-tumor-bearing rats progressively decreased as the KDH-8 tumor grew. IL-2 production from concanavalin-A-stimulated normal rat splenocytes was significantly inhibited by in vitro cultured KDH-8-tumor-cell-conditioned medium; this inhibition could be blocked by neutralizing the conditioned medium with anti-TGF beta antibody. TGF beta activities were found in KDH-8-tumor-tissue-conditioned medium without acid treatment and were found in tumor-cell-conditioned medium after acid treatment; TGF beta mRNA and TGF beta protein were found in cultured KDH-8 tumor cells. These results suggested that the KDH-8-tumor-derived TGF beta might be involved in the inhibition of IL-2 production from splenocytes. To determine whether bleomycin chemotherapy could reduce tumor-derived TGF beta and restore the immune responses, we treated KDH-8 tumor-bearing rats with bleomycin (5 mg/kg, one shot) at an appropriate time (before the occurrence of immunosuppression) resulting in a significant reduction of TGF beta activity in KDH-8 tumor tissues and restoration of IL-2 production from splenocytes of tumor-bearing rats; KDH-8 tumor growth ultimately regressed. In vitro experiments also showed that TGF beta activity, mRNA expression, and protein synthesis in KDH-8 tumor cells were reduced by bleomycin treatment, and that bleomycin-treated-KDH-8-tumor-cell-conditioned medium did not inhibit IL-2 production from normal rat splenocytes. These results suggest that bleomycin treatment restored IL-2 production in tumor-bearing rats through reducing the tumor-derived TGF beta.

[Mechanisms of enhanced accumulation of transferred LAK cells into tumor sites after chemotherapy]

We have previously reported that cancer chemotherapy prior to lymphokine activated-killer (LAK) cell-transfer gave synergistic increase in therapeutic effects of LAK adoptive immunotherapy on transplanted tumors, BMT-11 fibrosarcoma and 3LL lung carcinoma, in C57 BL/6 mice, and that transferred LAK cell-accumulation into tumor tissues was enhanced by treatment with anti-cancer drugs. The author tried to analyze mechanisms responsible for the enhanced LAK cell-accumulation into tumor tissues after chemotherapy by under agarose migration assay and LAK migration inhibitory assay. The author detected a chemotactic factor for LAK cells (LAK-attractant) and a migration inhibitory factor for LAK cells (LAK-MIF) in the conditioned medium of tumor tissues from mice treated with various anti-cancer drugs, which was not found in that of untreated tumor tissues. Since mRNA expression for transforming growth factor-beta 1 (TGF-beta 1) was found to enhance in tumor tissues after chemotherapy through RT-PCR, the author examined a possible participation of TGF-beta 1 as LAK-attractant in tumor tissues of mice treated with cyclophosphamide. Recombinant human TGF-beta 1 showed LAK-attractant activity, and anti-TGF-beta 1 antibody inhibited LAK-attractant activity in the conditioned medium. These findings indicate that TGF-beta 1 produced in tumor tissues of mice treated with anti-cancer drugs may be one of LAK-attractants. On the other hand, LAK-MIF activity was concentrated in the fraction of less than 3kDa which is a smaller molecule than that of TGF-beta 1. These findings suggest that both TGF-beta 1 and LAK-MIF produced in tumor tissues after chemotherapy contributed to the enhanced accumulation of transferred LAK cells into tumor tissues after the chemotherapy.

Enhancement of in vitro prostaglandin E2 production by mouse fibrosarcoma cells after co-culture with various anti-tumour effector cells

We have previously reported that an increase in the production of immunosuppressive prostaglandin E2 by a QR tumour (QR-32) is accompanied by progressive growth of the tumour in syngeneic C57BL/6 mice. In order to determine what kinds of cell and factor(s) enable QR-32 cells to promote PGE2 production, we investigated the amounts of PGE2 in the supernatant of QR-32 cells by co-culturing them with various anti-tumour effector cells. Significantly high levels of PGE2 production were observed when the QR-32 cells were co-cultured with lymphokine-activated killer (LAK) cells, natural killer (NK) cells, polymorphonuclear (PMN) leucocytes and streptococcal preparation (OK432)-activated or resident peritoneal macrophages (activated and resident macrophages). On the other hand, PGE2 production was not increased when QR-32 cells were co-cultured with cytotoxic T lymphocytes (CTLs) specific to QR-32 cells. The high levels of PGE2 production were partially or totally inhibited by the presence of radical scavengers such as superoxide dismutase (SOD), catalase and mannitol, although the cytotoxicity of LAK cells was not. We also exposed QR-32 cells to human recombinant cytokines and the growth factors which are produced when anti-tumour effector cells come in contact with tumour cells. Significant PGE2 production by QR-32 cells was observed when the cells were treated with interferon alpha (IFN-alpha), tumour necrosis factor alpha (TNF-alpha) and transforming growth factor beta (TGF-beta) (all P < 0.001). These results suggest that oxygen radicals produced by anti-tumour effector cells and inflammatory cytokines provoke QR-32 cells to produce large amounts of immunosuppressive PGE2.

Cell-surface sulfoglycolipids are involved in the attachment of renal-cancer cells to laminin

We investigated the role of sulfoglycolipids on human renal-cell carcinoma cells (SMKT-R3) in the attachment to a substrate adhesive protein, laminin. SMKT-R3 cells over-express sulfoglycolipids, including SM2, SM3 and SM4. When acidic glycolipid fractions, were extracted from SMKT-R3 cells, separated by HPTLC, and then overlaid with laminin, laminin bound specifically to SM3 and SM4. A monoclonal antibody, Sulph-1, reacting with SM3 and SM4 inhibited attachment of the cells to laminin but not to fibronectin, in a dose-dependent manner. In addition, when exogenous SM4 was incorporated into the cells, their attachment to laminin, but not to fibronectin, was enhanced. On the other hand, the incorporation of GalCer, which is a precursor of SM4, had no effect on adherence of the cells to laminin or to fibronectin. We also assayed haptotaxis, tumor-cell migration along a gradient of substratum-bound laminin. The incorporation of SM4 into the cells caused an approximately 3-fold increase of the haptotactic response to laminin compared with non- or GalCer-incorporation. These results taken together suggest that sulfoglycolipids on renal-cancer cells are involved in attachment to laminin and that they can modulate the metastatic potential of renal-cell carcinoma cells.

Augmented accumulation of transferred lymphokine-activated killer (LAK) cells at murine tumor sites through production of LAK-attractant facilitated by chemotherapy

We observed that effects of adoptive immunotherapy with lymphokine-activated killer (LAK) cells on BMT-11, a fibrosarcoma in C57BL/6 mice were improved by combination with cyclophosphamide (CY)-chemotherapy corresponding to enhanced accumulation at tumor sites of LAK cells. On the other hand, cytotoxic T lymphocytes (CTLs) which were able to accumulate at tumor sites more densely than LAK cells produced significant therapeutic effects by themselves. We have also found observed that LAK-attractant activity was detected in conditioned medium (CM) of CY-treated tumor tissue but not in the CM of untreated tumor tissue. These findings reveal that CY-chemotherapy facilitates LAK-attractant-production and enhances the accumulation in tumor tissue of LAK cells and that therapeutic effects of adoptive transfer of LAK cells are augmented by cancer chemotherapy through the enhanced accumulation of LAK cells.

Health care rationing

The following two-part article sets the scene for an ongoing dialogue in future Updates on rationing and its impact on our health care delivery system and on society at large. Part one establishes the framework for future discussions, while Part two zeros in on the efforts of one state to confront the issue head-on.