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.

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%).

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.

Monitoring the build-up of hydrogen polarization for polarized hydrogen-deuteride (HD) targets with nuclear magnetic resonance (NMR) at 17 T

We report on the frozen-spin polarized hydrogen-deuteride (HD) targets for photoproduction experiments at SPring-8/LEPS. Pure HD gas with a small amount of ortho-H₂ (∼0.1%) and a very small amount of para-D₂ (∼0.001%) was liquefied and solidified by liquid helium. The temperature of the produced solid HD was reduced to about 30 mK with a dilution refrigerator. A magnetic field (17 T) was applied to the HD to grow the polarization with the static method. After the aging of the HD at low temperatures in the presence of a high-magnetic field strength for three months, the polarization froze. Almost all ortho-H₂ molecules were converted to para-H₂ molecules. Most remaining para-D₂ molecules were converted to ortho-D₂ molecules. The para-H₂ and ortho-D₂ molecules exhibited weak spin interactions with the HD. If the concentrations of the ortho-H₂ and para-D₂ were reduced appropriately at the beginning of the aging process, the aging time can be shortened. We have developed a new nuclear magnetic resonance (NMR) system to measure the relaxation times (T₁) of the ¹H and ²H nuclei with two frequency sweeps at the respective frequencies of 726 MHz and 111 MHz and succeeded in the monitoring of the polarization build-up at decreasing temperatures from 600 mK to 30 mK at 17 T. Automatic NMR measurements with the frequency sweeps enabled us to omit the use of a manual tuning circuit and to remove magnetic field sweeps with eddy current heat. This technique enables us to optimize the concentration of the ortho-H₂ and to efficiently polarize the HD target within a shortened aging time.

Recent results of charged pion and kaon photoproduction on the proton at SPring-8/LEPS

We carry out photoproduction experiments by using linearly polarized photon beams with energies of 1.5-3 GeV at SPring-8/LEPS. One of our physics motivations is to understand reaction mechanisms of hadron photoproduction. We study (1) y→p→ π-Δ++, (2) y→p→ π+n, (3) y→p→ K+Λ(K+Σ0), and (4) y→p→ π+Δ0 reactions which produce (1) uu, (2) dd, (3) ss, and (4) dd quark-antiquark pairs in the final state. Differential cross sections and photon beam asymmetries have been measured at forward meson angles of 0.6 < cos θcm <1. Precise comparison between the π-Δ++ and π+Δ0 reactions plays an important role in the study of nucleon resonances. It enables to distinguish between N* and Δ* by taking the cross section ratios of the two reactions. We have measured preliminary cross section ratios dσ(π+Δ0)/dσ(π-Δ++). The ratios are found to be close to 1/3, which is expected from the exchange of isospin=1 in the t channel, for 0.966< cos θcm <1 and all the photon energies. The ratios become larger than 1/3 and close to 1 for larger angles and higher energy regions. The larger ratios might be due to A resonances, giving the ratio 4/3, excited in the intermediate state

Differential Cross Section and Photon-Beam Asymmetry for the γ[over →]p → π^{-}Δ^{++}(1232) Reaction at Forward π^{-} Angles for E_{γ}=1.5-2.95 GeV

Differential cross sections and photon-beam asymmetries for the γ[over →]p→π^{-}Δ^{++}(1232) reaction have been measured for 0.7<cosθ_{π}^{c.m.}<1 and E_{γ}=1.5-2.95  GeV at SPring-8/LEPS. The first-ever high statistics cross-section data are obtained in this kinematical region, and the asymmetry data for 1.5<E_{γ}(GeV)<2.8 are obtained for the first time. This reaction has a unique feature for studying the production mechanisms of a pure uu[over ¯] quark pair in the final state from the proton. Although there is no distinct peak structure in the cross sections, a non-negligible excess over the theoretical predictions is observed at E_{γ}=1.5-1.8  GeV. The asymmetries are found to be negative in most of the present kinematical regions, suggesting the dominance of π exchange in the t channel. The negative asymmetries at forward meson production angles are different from the asymmetries previously measured for the photoproduction reactions producing a dd[over ¯] or an ss[over ¯] quark pair in the final state. Advanced theoretical models introducing nucleon resonances and additional unnatural-parity exchanges are needed to reproduce the present data.

Interference Effect between ϕ and Λ(1520) Production Channels in the γp→K^{+}K^{-}p Reaction near Threshold

The ϕ-Λ(1520) interference effect in the γp→K^{+}K^{-}p reaction has been measured for the first time in the energy range from 1.673 to 2.173 GeV. The relative phases between ϕ and Λ(1520) production amplitudes were obtained in the kinematic region where the two resonances overlap. The measurement results support strong constructive interference when K^{+}K^{-} pairs are observed at forward angles but destructive interference for proton emission at forward angles. Furthermore, the observed interference effect does not account for the sqrt[s]=2.1  GeV bump structure in forward differential cross sections for ϕ photoproduction. This fact suggests possible exotic structures such as a hidden-strangeness pentaquark state, a new Pomeron exchange, or rescattering processes via other hyperon states.

Spin-density matrix elements for γp→K*0Σ+ at Eγ=1.85-3.0 GeV with evidence for the κ(800) meson exchange

The exclusive reaction γp→K(+)π(-)Σ(+) was measured for the first time using linearly polarized photons at beam energies from 1.85 to 2.96 GeV. Angular distributions in the rest frame of the K(+)π(-) system were fitted to extract spin-density matrix elements of the K(*0) decay. The measured parity spin asymmetry shows that natural-parity exchange is dominant in this reaction. This result clearly indicates the need for t-channel exchange of the κ(800) scalar meson.

Near-threshold Lambda(1520) production by the gamma(p)-->K{+}Lambda(1520) reaction at forward K+ angles

Differential cross sections and photon-beam asymmetries for the gamma(p)-->K{+}Lambda(1520) reaction have been measured with linearly polarized photon beams at energies from the threshold to 2.4 GeV at 0.6<cos(theta){c.m.}{K}<1. A new bump structure was found at W approximately 2.11 GeV in the cross sections. The bump is not well reproduced by theoretical calculations introducing a nucleon resonance with J<or=3/2. This result suggests that the bump might be produced by a nucleon resonance possibly with J>or=5/2 or by a new reaction process, for example, an interference effect with the phi photoproduction having a similar bump structure in the cross sections.

Near-threshold photoproduction of Lambda(1520) from protons and deuterons

Photoproduction of Lambda(1520) with liquid hydrogen and deuterium targets was examined at photon energies below 2.4 GeV in the SPring-8 LEPS experiment. For the first time, the differential cross sections were measured at low energies and with a deuterium target. A large asymmetry of the production cross sections from protons and neutrons was observed at backward K+/0 angles. This suggests the importance of the contact term, which coexists with t-channel K exchange under gauge invariance. This interpretation was compatible with the differential cross sections, decay asymmetry, and photon beam asymmetry measured in the production from protons at forward K+ angles.

Cross sections and beam asymmetry for K;{+}Sigma;{*-} photoproduction from the deuteron at E_{gamma}=1.5-2.4 GeV

The Sigma(1385) resonance, or Sigma;{*}, is well known as part of the standard baryon decuplet with spin J=3/2. Measurements of the reaction gammap-->K;{+}Sigma;{*0} are difficult to extract due to overlap with the nearby Lambda(1405) resonance. However, the reaction gamman-->K;{+}Sigma;{*-} has no overlap with the Lambda(1405) due to its charge. Here we report the first measurement of cross sections and beam asymmetries for photoproduction of the Sigma;{*-} from a deuteron target. The cross sections at forward angles range from 0.4 to 1.2 mub, with a broad maximum near E_{gamma} approximately 1.8 GeV. The beam asymmetries are negative, in contrast with positive values for the gamman-->K;{+}Sigma;{-} reaction.

Differential cross section and photon-beam asymmetry for the gamma n --> K+ Sigma- reaction at E gamma = 1.5-2.4 GeV

Differential cross sections and photon-beam asymmetries have been measured for the gamma n --> K+ Sigma- and gamma p --> K+Sigma0 reactions separately using liquid deuterium and hydrogen targets with incident linearly polarized photon beams of E gamma = 1.5-2.4 GeV at 0.6 < cos ThetacmK< 1. The cross section ratio of sigma K+ Sigma-/sigma K+ Sigma0, expected to be 2 on the basis of the isospin 1/2 exchange, is found to be close to 1. For the K+ Sigma- reaction, large positive asymmetries are observed, indicating the dominance of K* exchange. The large difference between the asymmetries for the K+ Sigma- and K+ Sigma0 reactions cannot be explained by simple theoretical considerations based on Regge model calculations.

Near-threshold diffractive psi-meson photoproduction from the proton

Photoproduction of a phi meson on protons was studied by means of linearly polarized photons at forward angles in the low-energy region from threshold to Egamma = 2.37 GeV. The differential cross sections at t = -|t|min do not increase smoothly as Egamma increases but show a local maximum at around 2.0 GeV. The angular distributions demonstrate that phi mesons are photoproduced predominantly by helicity-conserving processes, and the local maximum is not likely due to unnatural-parity processes.

Beam-polarization asymmetries for the p(gamma-->, K+)Lambda and p(gamma-->, K+)Sigma(0) reactions for E(gamma)=1.5-2.4 GeV

Beam polarization asymmetries for the p(gamma-->,K+)Lambda and p(gamma-->,K+)Sigma(0) reactions are measured for the first time for E(gamma)=1.5-2.4 GeV and 0.6<cos((theta(c.m.)(K+))<1.0 by using linearly polarized photons at the Laser-Electron-Photon facility at SPring-8 (LEPS). The observed asymmetries are positive and gradually increase with rising photon energy. The data are not consistent with theoretical predictions based on tree-level effective-Lagrangian approaches. Including the new results in the development of the models is, therefore, crucial for understanding the reaction mechanism and to test the presence of baryon resonances which are predicted in quark models but are thus far undiscovered.

Evidence for a narrow S = +1 baryon resonance in photoproduction from the neutron

The gamman-->K(+)K(-)n reaction on 12C has been studied by measuring both K+ and K- at forward angles. A sharp baryon resonance peak was observed at 1.54+/-0.01 GeV/c(2) with a width smaller than 25 MeV/c(2) and a Gaussian significance of 4.6sigma. The strangeness quantum number (S) of the baryon resonance is +1. It can be interpreted as a molecular meson-baryon resonance or alternatively as an exotic five-quark state (uuddsmacr;) that decays into a K+ and a neutron. The resonance is consistent with the lowest member of an antidecuplet of baryons predicted by the chiral soliton model.

Nutritional therapy of chronic hepatitis by whey protein (non-heated)

In an open study the clinical efficacy of milk serum (whey) protein (Immunocal; cysteine content: 7.6-fold higher than that of casein) isolated from fresh milk and purified without heating was evaluated in 25 patients with chronic hepatitis B or C. Immunocal (12 g as protein) food (mousse) was given twice a day, in the morning and evening, for 12 weeks (test period). Casein (12 g as protein) food (mousse) was similarly given for two weeks prior to the start of the supplement with Immunocal food (induction period) and for four weeks after the end of the supplement with Immunocal food (follow-up period). Serum alanine aminotransferase (ALT) activity was reduced, and plasma glutathione (GSH) levels increased in six and five of eight patients with chronic hepatitis B, respectively, 12 weeks after the start of the supplement with Immunocal food. Serum lipid peroxide levels significantly decreased, and interleukin (IL)-2 levels and natural killer (NK) activity significantly increased. However, there were no significant Immunocal-related changes in 17 patients with chronic hepatitis C. These findings suggest that the long-term supplement with Immunocal alone may be effective for improving liver dysfunctions in patients with chronic hepatitis B.

Production of (4)(double Lambda)H hypernuclei

An experiment demonstrating the production of double-Lambda hypernuclei in (K(-),K(+)) reactions on (9)Be was carried out at the D6 line in the BNL alternating-gradient synchrotron. The technique was the observation of pions produced in sequential mesonic weak decay, each pion associated with one unit of strangeness change. The results indicate the production of a significant number of the double hypernucleus (4)(double Lambda)H and the twin hypernuclei (4)(Lambda)H and (3)(Lambda)H. The relevant decay chains are discussed and a simple model of the production mechanism is presented. An implication of this experiment is that the existence of an S = -2 dibaryon more than a few MeV below the double Lambda mass is unlikely.

Dipole excitation of alpha clusters in (6)Li and (7)Li

Dipole excitations in highly excited energy regions of (6)He and (7)He nuclei were investigated via the ((7)Li,(7)Be) reaction with an incident energy of 65A MeV at forward scattering angles. The resonances at Q approximately equal to -30 MeV observed commonly for both (6)Li and (7)Li targets were found to be excited via both spin-flip and spin-nonflip transitions with DeltaL = 1. Based on the observed excitation energy, width, and cross section of each resonance, the relevant resonances are inferred to be analogs of the dipole resonances of alpha clusters in the (6)Li and (7)Li nuclei.

Observation of spin-orbit splitting in lambda single-particle states

The spin-orbit splitting of Lambda single-particle states in (13)(Lambda)C was measured. The 13C(K-,pi(-))(13)(Lambda)C reaction was used to excite both the 1/2(-) and 3/2(-) states simultaneously, which have predominantly 12C(0(+)) x p(Lambda) configuration. gamma rays from the states to the ground state were measured in coincidence with the pi(-)'s, by which ls splitting was found to be 152+/-54(stat)+/-36(syst) keV. The value is 20-30 times smaller than exhibited by the ls splitting in the nuclear shell model. This value gives us new insight into the YN interaction.

Soft dipole resonance in the neutron-skin nucleus 6He

A candidate for a soft dipole resonance, a dipole oscillation mode between a core cluster and a neutron skin, was observed at Ex = 4+/-1 MeV and with a width of 4+/-1 MeV in 6He via the 6Li( 7Li, 7Be) reaction at an incident energy of 65A MeV and forward scattering angles including 0 degrees. Its cross section is deduced to be sigma(0 degrees ) = 0.9+/-0.2 mb/sr. This value is comparable to that of the giant dipole resonance simultaneously measured.

Amitriptyline-induced constipation in cynomolgus monkeys is beneficial for the evaluation of laxative efficacy

In an attempt to create an animal model of constipation in monkeys, amitriptyline was administered to cynomolgus monkeys at doses of 10-160 mg/kg body weight via a nasogastric tube. Normal control monkeys excreted feces frequently throughout the day. Monkeys treated with amitriptyline at doses of 10-40 mg/kg showed delays in feces excretion. The 60 mg/kg treated monkeys for the most part did not excrete feces during the 24 h after amitriptyline administration. The 80 and 120 mg/kg treated monkeys did not excrete feces until 24 h from administration of amitriptyline, and also showed prolonged crouching and lethargy. On the other hand, 160 mg/kg treated monkeys died within 24 h after administration. We therefore felt that the optimal dose for creating constipation in the monkeys was 60 mg/kg. We tested the appropriateness of this amitriptyline-induced constipated monkey model by observing the effects of a new laxative, the herbal medicine ND-10 and the commercially available laxative bisacodyl. Control monkeys (those not receiving ND-10 or bisacodyl) treated with 60 mg/kg amitriptyline did not excrete feces up to 32 h after amitriptyline administration in 2 of 3 monkeys. However, all monkeys treated with one tablet of ND-10 excreted feces. Also, in 4 monkeys administrated with bisacodyl, 3 excreted feces. In this study, we confirmed that constipation can be caused in cynomolgus monkeys by oral administration of amitriptyline. This model may also be useful for the evaluation of laxatives.

Water extract of defatted rice bran suppresses visceral fat accumulation in rats

Rice bran has been reported to inhibit pancreatic lipase activity in vitro. This action shows that administration of rice bran may result in a decrease in plasma triglyceride levels and suppress accumulation of fat in vivo. We administered water extract of defatted rice bran (WED-rice bran) to rats to determine its effects. Single administration of WED-rice bran at a dose of 1 g/kg body weight caused a decrease in plasma triglyceride levels in fat emulsion induced hypertriglyceridemic rats. Four week administration of WED-rice bran suppressed accumulation of visceral fat and body weight gain without influencing food consumption, liver function, and renal function. These results indicate that a reduction of plasma triglycerides and suppression of visceral fat accumulation may be induced by pancreatic lipase inhibition caused by administration of WED-rice bran.

Trehalose can be used as a parenteral saccharide source in rabbits

Trehalose is a saccharide that possesses no reducing group and so has possible use in parenteral nutrition, especially because it can be stored with amino acids without undergoing the Maillard reaction. To evaluate this possibility, a series of experiments were conducted. The activity of trehalase, an enzyme that metabolizes trehalose to glucose, was measured in rabbit serum and kidney. Conversion of trehalose to glucose and excretion of trehalose in the urine were measured in rabbits administered 10% trehalose intravenously. The effects on nutritional indices as indicators of its use as an energy source were also measured in rabbits infused with 8.23 g.kg-1.d-1 (4. 12 g.kg-1 on d 1) of trehalose for 5 d. Trehalase activity resembled maltase activity, both being high in the renal cortex (2.04 +/- 0.71 and 2.93 +/- 0.26 micromol.g-1.min-1, respectively), weak in the medulla, and undetectable in the serum. Serum glucose and insulin concentrations were increased significantly by trehalose infusion. Significant elevations were observed in serum glucose but not insulin levels by maltose infusion. On the other hand, urinary excretion of trehalose (1.1 +/- 2.1% of dose) was significantly lower than that of maltose (10.1 +/- 4.9% of dose). Similar effects of trehalose and maltose infusions as seen in normal rabbits occurred in rabbits with alloxan diabetes (urinary excretion rate, 3. 8 +/- 3.0% of the infused trehalose dose and 35.6 +/- 9.7% of the infused maltose dose). Nitrogen balance was positive in the trehalose- and glucose-infused normal rabbits with significant difference from the control group infused with saline, suggesting that trehalose was used as an energy source. These results suggest that trehalose has the potential for use as a saccharide source for parenteral nutrition.

The novel analgesic compound OT-7100 (5-n-butyl-7-(3,4,5-trimethoxybenzoylamino)pyrazolo[1,5-a]pyrimid ine) attenuates mechanical nociceptive responses in animal models of acute and peripheral neuropathic hyperalgesia

We investigated the effects of OT-7100, a novel analgesic compound (5-n-butyl-7-(3,4,5-trimethoxybenzoylamino)pyrazolo[1,5-a]pyrimidi ne), on prostaglandin E2 biosynthesis in vitro, acute hyperalgesia induced by yeast and substance P in rats and hyperalgesia in rats with a chronic constriction injury to the sciatic nerve (Bennett model), which is a model for peripheral neuropathic pain. OT-7100 did not inhibit prostaglandin E2 biosynthesis at 10(-8)-10(-4) M. Single oral doses of 3 and 10 mg/kg OT-7100 were effective on the hyperalgesia induced by yeast. Single oral doses of 0.1, 0.3, 1 and 3 mg/kg OT-7100 were effective on the hyperalgesia induced by substance P in which indomethacin had no effect. Repeated oral administration of OT-7100 (10 and 30 mg/kg) was effective in normalizing the mechanical nociceptive threshold in the injured paw without affecting the nociceptive threshold in the uninjured paw in the Bennett model. Indomethacin had no effect in this model. While amitriptyline (10 and 30 mg/kg) and clonazepam (3 and 10 mg/kg) significantly normalized the nociceptive threshold in the injured paw, they also increased the nociceptive threshold in the uninjured paw. These results suggest that OT-7100 is a new type of analgesic with the effect of normalizing the nociceptive threshold in peripheral neuropathic hyperalgesia.

Streptozotocin-induced diabetic cynomolgus monkey is a model of hypertriglyceridemia with low high-density lipoprotein cholesterol

Hypertriglyceridemia with low high-density lipoprotein (HDL) cholesterol is a risk factor of cardiovascular disease. We attempted to create an animal model of hypertriglyceridemia with low HDL cholesterol by intravenously injecting 30 mg/kg body weight streptozotocin (STZ) to cynomolgus monkeys. This induced hypoinsulinemia and resulted in a decrease in postheparin plasma lipoprotein lipase (LPL) activity and LPL enzyme mass, reduction of plasma HDL cholesterol and elevation of triglycerides. Low HDL cholesterol subsequently caused a reduction of HDL2b cholesterol, while hypertriglyceridemia caused an elevation of very low-density lipoprotein (VLDL) triglyceridemia. Apolipoprotein CII, a co-factor of LPL, was not affected by STZ administration. These results show that hypertriglyceridemia with low HDL cholesterol results from a reduction of LPL activity without affecting apolipoprotein CII after STZ administration. The STZ-induced diabetic cynomolgus monkey is a model of hypertriglyceridemia with low HDL cholesterol, and may be potentially beneficial for studying atherosclerosis caused by hypertriglyceridemia with low HDL cholesterol.

The novel compound NO-1886 activates lipoprotein lipase in primary cultured adipose and skeletal muscle cells

As previously reported, we have discovered that a novel compound, NO-1886 (diethyl 4-[(4-bromo-2-cyanophenyl)carbamoyl] benzylphosphonate) has a powerful lipoprotein lipase (LPL) stimulating activity. Oral administration of NO-1886 increased LPL activity in postheparin plasma of experimental animals, resulting in the reduction of plasma triglyceride with concomitant elevation of high density lipoprotein cholesterol. However, the mechanism of NO-1886 on LPL activity is not clearly understood. To address this problem, we examined the effect of NO-1886 on LPL activity in primary rat cell culture isolated from adipose and skeletal muscle tissue. NO-1886 increased total LPL activity 18% and 23% in adipocytes at a dose of 3 and 10 micrograms/ml, respectively, and 43% at a dose of 10 micrograms/ml in skeletal muscle cells. These results indicate that NO-1886 may act directly on LPL-producing cells such as adipose and skeletal muscle.

Limitation of stunning in dog myocardium by nucleoside and nucleotide mixture, OG-VI

OG-VI is a solution composed of 30 mM inosine, 30 mM sodium 5'-guanylate, 30 mM cytidine, 22.5 mM uridine, and 7.5 mM thymidine, expecting to use for total parenteral nutrition. We examined the effect of OG-VI on myocardial contractile dysfunction during reperfusion after ischemia (myocardial stunning) in dogs. Pentobarbital-anesthetized dogs were subjected to 20-min left anterior descending coronary artery ligation followed by 30-min reperfusion. Saline, OG-VI or its constituents [inosine and sodium 5'-guanylate mixture (IG), and cytidine, uridine, and thymidine mixture (CUT)], or 5-amino-4-imidazole carboxamide riboside (AICAr) was infused at 0.1 mL.kg-1.min-1, starting 30 min before the ischemia. The contractile function was determined by ultrasonometry and assessed as % segment shortening (%SS). %SS was markedly decreased by ischemia, and returned toward pre-ischemic level after reperfusion, although the recovery was incomplete. The %SS was almost completely recovered by OG-VI and IG, and to a lesser extent by AICAr; CUT was ineffective. In the presence of 1 mg.kg-1 of 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, a selective adenosine A1 receptor antagonist), cardioprotective effect of OG-VI on stunned myocardium was still observed. In conclusion, infusion of OG-VI improved myocardial contractile dysfunction in stunned myocardium. This effect was more potent than its constituents and AICAr. Adenosine A1 receptors are not involved in the mechanism.

Effects of OG-VI, a nucleoside/nucleotide mixture, and its constituents on myocardial stunning in dogs

BACKGROUND

OG-VI is a solution composed of 30 mmol/l inosine, 30 mmol/l sodium 5'-guanylate, 30 mmol/l cytidine, 22.5 mmol/l uridine and 7.4 mmol/l thymidine, and has a protective effect on stunned myocardium. We examined the effects of the constituents of OG-VI on stunned myocardium in dogs, and compared them with that of acadesine (5-amino-4-imidazole carboxamide riboside; AlCAr) to try to elucidate the mechanism of the effect of OG-VI.

METHODS

Dogs anesthetized with pentobarbital were subjected to left anterior descending coronary artery ligation for 20 min followed by reperfusion for 30 min. Saline, OG-VI, its purine component (inosine and sodium 5'-guanylate; IG), its pyrimidine component (cytidine, uridine and thymidine; CUT) or AlCAr (30 mmol/l) was infused at 0.1 ml/kg/min, starting 30 min before the ischemia. Myocardial segment shortening function was determined by sonomicrometry. The tissue level of adenosine triphosphate (ATP) was determined in the hearts reperfused for 30 min.

RESULTS

Following reperfusion, the group treated with saline showed an incomplete recovery of segment shortening function, which had been decreased by ischemia, to the pre-ischemic level. The segment shortening function was almost completely recovered in the groups treated with OG-VI and IG, to a lesser extent in the AlCAr-treated group, and CUT was found to be ineffective. The levels of ATP in the OG-VI- and AlCAr-treated groups were significantly higher than that in the saline-treated group. In contrast to saline, IG and CUT were both ineffective at increasing ATP during reperfusion.

CONCLUSION

Of the compounds tested, only OG-VI improves both ATP levels and segment shortening recovery in stunned dog myocardium. The increase in ATP levels is not the only factor responsible for contractile recovery.

[The mechanism of potentiation of the antitumor effect of 5-fluorouracil by methionine-free intravenous amino acid solution (AO-90) in rats]

AO-90, a methionine-free intravenous amino acid solution (7.43%) showed to potentiate the antitumor effect of 5-fluorouracil (5-FU) when concomitantly used as the nitrogen source in total parenteral nutrition (TPN) in Yoshida sarcoma (YS)-bearing rats. In the present experiment, this potentiation mechanism was studied by determining the serum methionine level and tumor methylenetetrahydrofolate (CH2FH4) content in YS-bearing Donryu rats given AO-90 (nitrogen 0.73g/kg on the 1st day and 1.46g/kg for the remaining 6 days) by TPN for 1 week. The rats were subcutaneously inoculated with 10(4) YS cells in the dorsum 3 days before the start of TPN. Inhibition of thymidylate synthase activity in tumor tissue after dosing of AO-90 (nitrogen 0.68g/kg on the 1st day and 1.36 g/kg for the remaining 6 days) by TPN along with daily intraperitoneal dosing of 5-FU (10 mg/kg) was also evaluated with the inoculation of 10(6) tumor cells. The results were compared with those in tumor-bearing rats given TPN with a commercially available amino acid solution containing methionine. On day 5 of TPN, the tumor-bearing rats given AO-90 showed a significantly lower serum methionine level than the control rats: 101 +/- 11 mumol/l versus 29 +/- 14 mumol/l (p < 0.01); and a higher CH2FH4 content in tumor: 7.0 +/- 2.8 pmol/g protein versus 23.7 +/- 16.6 pmol/g protein (p < 0.05). Thymidylate synthase inhibition was 81.2 +/- 5.1% in the AO-90 group and 30.9 +/- 26.3% in the control group (p < 0.01). The results of the present study suggest that AO-90 potentiate the antitumor effect of 5-FU by biochemical modulation. AO-90 concomitantly given with 5-FU for 7 days was effective not only in the allogeneic tumor model, but also in WKAH and SHR rats previously inoculated with 10(6) of syngeneic KDH-8 hepatoma cells and SST-2 adenocarcinoma cells, respectively. Weight of SST-2 adenocarcinoma in SHR rats after the TPN period was significantly smaller in the AO-90 group than in the control rats given methionine-containing TPN and 5-FU: 2.66 +/- 0.91 versus 5.12 +/- 2.11 (p < 0.05).

Determination of absorption and endogenous excretion of iron in man by monitoring fecal excretion of a stable iron isotope (58Fe)

The absorption and endogenous excretion of iron in man was studied by monitoring the fecal excretion of a stable iron isotope (58Fe). The study was carried out for 12 healthy volunteers who were divided into two groups. Group I received 58Fe-labeled ferric ammonium citrate (III) (58FeAC) equivalent to 6 mg of iron as a control, and group II received a combination of 500 mg of vitamin C and 58FeAC. A new formula was used to calculate the 58Fe absorption ratio reflecting the pool of iron in the intestinal cells, and the ratio was compared with that obtained from Janghorbani's formula, which has been used as one of the common methods. As a result, the 58Fe absorption ratio in group II was statistically significantly higher than that of group I (34.4 +/- 6.1% vs. 15.0 +/- 5.5%, M +/- SD) using Janghorbani's formula. The similar absorption ratio (34.1 +/- 6.0% vs. 14.8 +/- 5.5%) was also obtained by our new formula. Our results confirmed the previous findings that the availability of iron is stimulated by the supplementation of vitamin C. Both formulae agreed in the absorption of iron, indicating that the endogenous excretion of iron (caused by the desquamated cells) in the intestine does not disguise the iron absorption.

Exercise-induced changes in branched chain amino acid/aromatic amino acid ratio in the rat brain and plasma

Central fatigue was induced by running rats on a treadmill. Amino acid and ammonia metabolism in the brain and blood were followed with time to correlate its changes with physical exhaustion. The blood ammonia level did not change during running, but was prominently increased at exhaustion. The brain level of ammonia was also prominently high at the end of exercise with a time course of change similar to that of the blood level. Plasma concentrations of branched chain amino acids (BCAA) and aromatic amino acids (AAA) increased as the animals continued to run; however, the plasma BCAA/AAA ratio was definitely depressed at exhaustion. This was also true with the brain BCAA/AAA ratio. A positive correlation was demonstrated between the plasma and brain BCAA/AAA ratios at r=0.5040 and P less than 0.05. These exercise-related changes suggest that physical exercise-induced central fatigue involves not only an increase in brain ammonia, but also a disturbance in brain amine metabolism accompanying plasma and brain BCAA/AAA ratio depression. Furthermore, the ammonia level and BCAA/AAA ratio in the brain correlated with those in the blood. It is reasonable to consider that the blood ammonia concentration and plasma BCAA/AAA ratio may serve as important indices of the clinical condition of exercise-induced central fatigue.

[Study of the ameliorating effects of an enteral nutrient for liver failure on hepatic encephalopathy: effects of SF-1008C on plasma and brain free amino acids, intracerebral amine concentrations and electroencephalogram in portacaval shunted rats with ammonia loading]

The ameliorating effects of an enteral nutrient for liver failure (SF-1008C), which is enriched with branched-chain amino acids (BCAA) and includes few aromatic amino acids (AAA), were investigated. The blood ammonia, plasma and brain free amino acids, intracerebral amine concentrations and electroencephalogram were measured in portacaval shunted rats with 10% ammonium acetate (3 ml/kg, i.p.) (PCS) as a model of hepatic encephalopathy. The blood ammonia and plasma free amino acid concentrations in PCS rats were significantly increased in comparison to sham-operated (Sham) rats. Thus, the plasma BCAA/AAA ratio in PCS rats was appreciably reduced. Concomitant with the abnormal plasma amino acid concentrations, the brain free amino acid concentrations in PCS rats were markedly increased in comparison to the Sham rats. Moreover, the intracerebral tryptophan (Trp) and 5-hydroxyindol acetic acid (5-HIAA) concentrations were significantly increased, and the intracerebral dopamine (DA) concentration was significantly decreased in the PCS rats. The intracerebral serotonin (5-HT) and norepinephrine (NE) concentrations were, however, hardly changed. A smaller voltage for the electroencephalogram was used in the PCS rats than in the Sham rats. Abnormal plasma and brain free amino acid concentrations in PCS rats were normalized by oral administration of SF-1008C, and the low voltage electroencephalograms in the PCS rats were suppressed. On the other hand, abnormal plasma and brain free amino acid concentrations in the PCS rats were hardly normalized by oral administration of ED-AC, an elemental diet based on an amino acid composition of egg protein. These results suggest that SF-1008C affects brain free amino acids, intracerebral amine concentrations and electroencephalogram by ameliorating abnormal plasma free amino acid concentrations. Moreover, there is a highly significant correlation between the plasma BCAA/AAA ratio and the brain BCAA/AAA ratio, and this finding suggests that the plasma free amino acid patterns reflect the brain free amino acid patterns.

[Metabolic fate of carteolol hydrochloride (OPC-1085), a new beta-adrenergic agent. (3) Autoradiographic total body distribution studies in mice]

Distribution of a new beta-adrenergic blocking agent, 3H-carteolol in mice was studied by whole body autoradiography. The distribution of radioactivity was observed in all organs except the eyes and brain, with particularly high specific activities in the kidneys, liver, gall bladder and content in the intestines within a short time after either oral or intravenous administration. The radioactivity was then promptly eliminated from all tissues and organs, and excreted almost entirely in the urine and bile. Propranolol is known to be distributed at a high concentration in the brain, whereas the concentration of (3H-) carteolol detectable in the brain was slight. In the adrenal gland, the radioactivity was localized in the medulla. Radioactivity was detected also in the stomach contents after the intravenous administration. The distribution of radioactivity in the fetus through the placenta was less than that in the major organs of the mother mouse, and the elimination of the activity was more rapid in the fetus than in mother. These findings indicate that carteolol and its metabolites do to some extent pass through the blood-brain barrier and placenta.