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Positron annihilation lifetime (PAL) spectra were measured for two different kinds of polymers: polypropylene (PP) and polytetrafluoroethylene (PTFE), during sorption of vapors of the following molecules: n-hexane, cyclohexane, benzene, methyl methacrylate, acrylic acid, and water. The behavior of ortho-positronium (o-Ps) annihilation parameters: lifetime, τ3, and intensity, I3, can be explained by considering different sorption mechanisms in rubbery and glassy polymers. The mean size of the intermolecular-space holes and the relative free-volume fraction of PP and PTFE were estimated before and during the sorption process from the o-Ps parameters obtained. Sorption of n-hexane, cyclohexane, and benzene in both polymers affect the o-Ps component in a systematic way, for PP τ3 and I3 tend to decrease, while in PTFE, τ3 stay almost constant and I3 diminishes. These effects are interpreted in relation to the different states of the polymers studied: rubbery for PP and glassy for PTFE. In case of methyl methacrylate molecules, the behavior of o-Ps parameters was more complicated. For acrylic acid and water, their associated polarity provokes a diminution in I3, which is explained from the viewpoint of the spur model of positronium formation. Large changes in the mean size and the fraction of free volume, as well as their constant behavior in some cases, were interpreted to be due to positive or negative interactions, respectively, between vapor molecules and PP and PTFE, which could be correlated with the solvent-interaction parameters calculated. © 1995 John Wiley & Sons, Inc.

A permanent and stand-alone neutron-induced prompt γ-ray analysis (PGA) system, usable at both cold and thermal neutron beam guides of JRR-3M has been constructed. The characteristics of the system, including neutron beam and γ-ray spectrometer were measured. Owing to the absence of fast neutrons and the low γ-ray background, analytical sensitivities and detection limits better than those in other PGA systems have been achieved. Analytical results of ten elements in Standard Reference Material of Coal Fly Ash agreed well with those obtained by other methods. Isotopic analysis of Ni and its application to accurate and precise determination of Ni by stable isotope dilution method were performed.

The irradiation effects on five kinds of polyethylenes (PEs) were studied from the viewpoints of mechanical properties, free radicals and positron annihilation. The degradation of the mechanical strength of samples irradiated by 60Co γ-rays was evaluated based on the elongation at break and the tensile strength. Fully stretched PE with a crystallinity larger than 99% was greatly affected by γ-irradiation. In low-density PEs free radicals were detectable only above 70 kGy, and sharply increased above 100 kGy. A detectable number of free radicals was obtained even at 0.1 kGy in PEs haaving high crystallinity. At around 100 kGy, the increase in the intensity (I3) of ortho-positronium (o-Ps), seems to be associated with an increase in the mechanical strength. Contrary to the expectation that the o-Ps seeks intermolecular space holes only in amorphous regions, the I3 obtained in PEs with nearly 100% crystallinity was almost half that low-density PEs, and τ3 had similar values. This suggests that even in crystalline regions the o-Ps seeks intermolecular space holes comparable to those in the amorphous regions.

Systematic studies of the phase and density dependence of the delayed annihilation time spectra of antiprotons (DATS) in gaseous, liquid, and solid helium have been performed using the low energy antiproton ring at CERN. The results show a small but significant dependence of DATS on the phase and density of the helium medium. The average lifetime of antiprotons ([ital T][sub [ital a][ital v]]) in gas at 10--30 K was found to be 4.03[plus minus]0.02 [mu]s. In liquid helium [ital T][sub [ital a][ital v]] decreases with density from 3.0 [mu]s at 1 bar to 2.5 [mu]s at 60 bars, while in solid helium its value is 2.14[plus minus]0.03 [mu]s, 20% shorter than that in liquid helium of the same density. There is no change of DATS betweeen normal 1-bar liquid and superfluid helium. An isotope effect between [sup 4]He and [sup 3]He similar to the one previously observed in the gas phase has also been found for liquid helium. All the data can be fitted fairly well with a simple three-level chain decay model with describes the general structure of DATS, characterized by downaward curving behavior on a logarithmic scale at later times and by the presence of a short-lived component.more » No delayed annihilation was observed in lithium.« less

An important approach to the design of antiallergic agents with reduced penetration into the central nervous system (CNS) is described. A series of 3-[(5,11- dihydro[1]benzoxepino[4,3-b]-pyridin-11-ylidene)piperidino]propion ic acid derivatives (31-47) and related compounds (48-54) were synthesized and evaluated for antiallergic activity and penetration of a compound into the CNS in comparison with the corresponding 6H-dibenz[b,e]oxepin derivative (3). Combination of zwitterionization and introduction of a pyridine component resulted in an increase in antiallergic activity and a great reduction of penetration into the CNS, which was evaluated by the selectivity (B/A) of antihistaminic activities in the central system [ID50 value (B) for ex vivo H1 binding to mouse brain membranes] and in the peripheral system [ED50 value (A) for inhibitory effect on histamine-induced increase in vascular permeability in mice]. This surprising reduction of penetration into the CNS could be considered on the basis of an increase in hydrophilicity caused by both of the zwitterionization and the introduction of a pyridine component. 3-[4-(8-Fluoro-5,11-dihydro[1]benzoxepino[4,3- b]pyridin-11-ylidene)piperidino]propionic acid (33) exhibited a strong antiallergic effect in various experimental models and very low penetration into the CNS. Compound 33 (HSR-609) is now under clinical trial as a promising antiallergic agent with greatly reduced penetration into the CNS.

Using a new method for reconstructing the depth profile of defects in an iondashirradiated sample by using slow positrons, the depth profiles of vacancy-type defects in 316 stainless steel samples, irradiated with 250 keV Ar ions to a dose of 7.5 × 10 19 m −2 at room temperature, have been calculated from Doppler-broadening S parameters measured as a function of positron energies up to 16 keV. Without assuming any type of shape for the defect profiles, such as Gaussian, the defect profiling is done using a least-squares fitting method. The resulting profile suggests that in as-irradiated 316 stainless steel samples with lower carbon content, the defect distribution peaks at a depth four times larger than that of the ion range. After annealing at a high temperature of 1253 K for 0.5 h, the fitted profile shows that the peak around the average ion range is highly enhanced. While in the steel added with 0.3 wt% titanium, the profile exhibits almost no peak after annealing at 1073 K. The results indicate that the radiationdashproduced vacancy clusters are stabilized by the implanted Ar atoms more effectively in the Ti-free steel than in the Ti-added steel.

The effect of both administration and withdrawal of doxazosin on patients with essential hypertension was evaluated by twenty-four-hour ambulatory blood pressure (BP) monitoring. Six hypertensive men were treated with doxazosin starting at 1 mg/day, and the dosage was titrated at weekly intervals up to a maximum of 8 mg/day. The twenty-four-hour BP profile was monitored noninvasively before treatment, in the fourth week of treatment, and on days 2 and 7 after the discontinuation of doxazosin. The average twenty-four-hour systolic and diastolic BPs (SBP and DBP) were lowered by doxazosin treatment and returned to the pretreatment levels within two days of doxazosin withdrawal. Doxazosin treatment produced a significant decrease in the daytime SBP and DBP but not in the nighttime BP values. The daytime BP decrease was no longer detected on days 2 and 7 after drug withdrawal. The twenty-four-hour pulse rate was not influenced by either doxazosin administration or discontinuation. The plasma norepinephrine concentration and plasma renin activity were increased by doxazosin treatment and were decreased by drug withdrawal. There was no rebound hypertension following doxazosin withdrawal. Thus, the present study using twenty-four-hour BP monitoring showed that doxazosin treatment reduced the daytime BP in patients with essential hypertension and that this reduction was abolished within two days after doxazosin discontinuation.

Using the RIKEN AVF cyclotron, various targets were irradiated with proton or deuteron beams to produce β+-decay radioisotopes. Slow positrons are extracted backward at an angle of 30° to the incident ion beam using a well annealed W film, with a thickness of 10 μm, as a moderator. This geometry was chosen to allow for both the use of various kinds of target materials and the in-beam slow positron extraction during ion beam irradiation. In preliminary experiments, a slow e+ intensity of ∼5.6 × 104 e+/s was obtained from BN by irradiating protons with an energy of 14 MeV and a current of 4 μA. From an Al target irradiated with a proton beam with an energy of 10 MeV and a current 3.6 μA, a slow e+ intensity of ∼5.5 × 102 e+/s was also obtained. By irradiating a deuteron beam with 8 MeV energy and 1.3 μA current, slow e+ intensities of ∼4.2 × 103 e+/s and ∼3.4 × 103 e+/s were obtained from carbon and Si3N4 respectively. Using a pulsed ion beam, background noise was eliminated almost completely in three-coincidence measurement.

An image of reemitted positrons has been produced in a proto-type positron transmission-type reemission microscope by using the electrostatic intense slow positron beam from an electron LINAC. RHEPD experiments have then been performed on H-terminated Si(111).

Cross-linked glassy polystyrene (PS) sorbents with different degree of linking (24–150%) were studied using positron annihilation lifetime spectroscopy. Unusual effect of PS swelling due to polymer cross-linking was investigated. Annihilation lifetimes longer than 50 ns, one of the longest among those known for polymer materials, were found. These results and some additional data enabled obtaining information on the parameters of elementary free volumes responsible for the properties of the sorbents.

We report a transformative, all inorganic synthesis method of preparing supported bimetallic Pd(3)Ag alloy nanoparticles. The method involves breaking down bulk Pd(3)Ag alloy into the nanoparticles in liquid lithium, converting metallic Li to LiOH, and transferring Pd(3)Ag nanoparticles/LiOH mixture onto non-water-soluble supports, followed by leaching off the LiOH with water under ambient conditions. The size of the resulting Pd(3)Ag nanoparticles was found narrowly distributed around 2.3 nm characterized by transmission electron microscope (TEM). In addition, studies by X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS) spectroscopy, and X-ray absorption near edge structure (XANES) spectroscopy showed that the resulting Pd(3)Ag nanoparticles inherited similar atomic ratio and alloy structure as the starting material. The synthesized Pd(3)Ag nanoparticles exhibited excellent catalytic activity toward hydrogenation of acrolein to propanal.

The Japanese Society of Emergency Pediatrics has formulated evidence-based guidelines for the management of intussusception in children in order to diagnose intussusceptions promptly, to initiate appropriate treatment as early as possible, and to protect intussuscepted children from death.Literature was collected systematically via the Internet using the key words "intussusception" and "children." The evidence level of each paper was rated in accordance with the levels of evidence of the Oxford Center for Evidence-based Medicine. The guidelines consisted of 50 clinical questions and the answers. Grades of recommendation were added to the procedures recommended on the basis of the strength of evidence levels.Three criteria of "diagnostic criteria,""severity assessment criteria," and "criteria for patient transfer" were proposed aiming at an early diagnosis, selection of appropriate treatment, and patient transfer for referral to a tertiary hospital in severe cases. Barium is no longer recommended for enema reduction (recommendation D) because the patient becomes severely ill once perforation occurs. Use of other contrast media, such as water-soluble iodinated contrast, normal saline, or air, is recommended under either fluoroscopic or sonographic guidance. Delayed repeat enema improves reduction success rate, and is recommended if the initial enema partially reduced the intussusception and if the patient condition is stable.The guidelines offer standards of management, but it is not necessarily the purpose of the guidelines to regulate clinical practices. One should judge each individual clinical situation in accordance with experiences, available devices, and the patient's condition.

Granulocyte colony-stimulating factor (G-CSF) is a cytokine that is clinically used to treat neutropenia. G-CSF also has non-hematopoietic functions and could potentially be used to treat neuronal injury. To confirm the safety and feasibility of G-CSF administration for acute spinal cord injury (SCI), we have initiated a phase I/IIa clinical trial of neuroprotective therapy using G-CSF.The trial included a total of 16 SCI patients within 48 h of onset. In the first step, G-CSF (5 μg/kg/day) was intravenously administered for 5 consecutive days to 5 patients. In the second step, G-CSF (10 μg/kg/day) was similarly administered to 11 patients. We evaluated motor and sensory functions of patients using the American Spinal Cord Injury Association (ASIA) score and ASIA impairment scale (AIS) grade.In all 16 patients, neurological improvement was obtained after G-CSF administration. AIS grade increased by one step in 9 of 16 patients. A significant increase in ASIA motor scores was detected 1 day after injection (P0.01), and both light touch and pin prick scores improved 2 days after injection (P0.05) in the 10 μg group. No severe adverse effects were observed after G-CSF injection.These results indicate that intravenous administration of G-CSF (10 μg/kg/day) for 5 days is essentially safe, and suggest that some neurological recovery may occur in most patients. We suggest that G-CSF administration could be therapeutic for patients with acute SCI.

The positron annihilation lifetime method (PAL) has been applied to study the characteristics of polyethylenes (PEs) at low temperatures between 273 and 100 K. It has been found that the intensity (I3) of the long-lived component of positronium (Ps) showed an increase in non-annealed PE and annealed PE in vacuo. However, PAL in PEs annealed in an atmosphere containing oxygen did not show such an increase. It has been indicated that the latter effect is due to formation of carbonyl groups through oxidation during the annealing.

Positron lifetime measurements were performed for two different polymers (low density polyethylene and a polyimide 6FDA-TMPD) during sorption of various vapors (n-hexane, cyclohexane, benzene, acrylic acid, methyl acrylate). The vapor sorption affected the long-lived component (ortho-positronium component) in a systematic way regardless of the kind of vapor, i.e. for the polyethylene both the lifetime and the intensity of the long-lived component were enhanced, while for the polyimide they were decreased significantly. These different effects are interpreted in terms of the different aggregation states, i.e. rubbery for the polyethylene and glassy for the polyimide.

Positron annihilation lifetimes (PAL) have been measured for polythylenes (PEs) under differenr conditions of heat treatment. It is shown that the intensity, I 3 , of the long-lived component of positronium (Ps) shows hystereses between the heating and cooling processes due to aging effect. It is also shown that about half of Ps observed at low temperatures below the glass transition is inhibited after the sample is heat-treated above the melting point in the atmosphere containing oxygen. It is suggested that carbonyl groups (C0) formed by thermal oxidation can inhibit Ps formation through trapping the precursors of Ps, e + and/or e - .

The N-alkylcarboxylic acids of 1,2,3,4,10,14b-hexahydrodibenzo[c,f]pyrazino[1,2-alpha]az epi ne (6a) and 2,3,4,9-tetrahydro-1H-dibenzo[3,4: 6,7]cyclohepta[1,2- c]pyridine (6b) were synthesized and examined for pharmacological activities in vitro: an inhibitory effect on the monoamine [noradrenaline (NA) and 5-hydroxytryptamine (5-HT)] uptake into the rat crude synaptosome, an inhibitory effect on the 5-HT- and NA-induced contraction in the isolated rabbit aorta and on the histamine- and acetylcholine-induced contraction in the isolated guinea-pig ileum, and binding affinity for alpha 2-adrenoceptor and D2-receptor. The in vitro tests indicated that zwitter-ionization was capable of maintaining antihistaminic activity while greatly reducing other pharmacological activities such as effects on central nervous system. 3-[2,3,4,9-Tetrahydro-1H-dibenzo[3,4: 6,7]cyclohepta[1,2- c]pyridin-2-yl]propionic acid (6b-2), selected as a candidate antiallergic agent having equally potent activities in rats and guinea-pigs, exhibited strong inhibitory effects on 48 h homologous passive cutaneous anaphylaxis (PCA) in rats (ED50 = 0.012 mg/kg, p.o.) and on histamine-induced bronchoconstriction in anesthetized guinea-pigs (ED50 = 0.0088 mg/kg, p.o.).

The transport mechanism of the H1antagonist mepyramine at the blood-brain barrier (BBB) was studied by using primary cultured monolayers of bovine brain capillary endothelial cells (BCEC). The initial uptake of [3H]mepyramine into the BCEC showed strong temperature and concentration dependency, indicating that it involves both saturable and nonsaturable processes. Transport at the luminal membrane may be the rate-limiting process in the transcellular transport, since the values of the uptake coefficient of [3H]mepyramine at the luminal membrane (609 µl/mg protein/min) and the transcellular permeability coefficient (488 µl/mg protein/min) are very similar. The initial uptake of [3H]mepyramine was not affected by metabolic inhibitors, but was stimulated by preloading with the drug. Mepyramine appears to be transported into the BCEC by a carrier-mediated transport system which does not require metabolic energy, probably via a facilitated diffusion mechanism.

The effect of long-term doxazosin treatment on normotensive subjects was evaluated by 48-hour ambulatory blood pressure (BP) monitoring (ABPM). Eight normotensive volunteers were given 1 mg of doxazosin per day, and the dose was titrated every week up to 8 mg/day. The 48-hour ABPM, using a noninvasive device, was performed before treatment and during the 4th week of treatment. Doxazosin did not decrease the average 48-hour systolic BP, but diastolic BP decreased slightly (3 mmHg). This slight decrease in 48-hour diastolic BP was observed during the daytime. The 48-hour pulse rate (PR) was clearly elevated by doxazosin, which was attributed to tachycardia at night. Thus, the present study using 48-hour ABPM indicated that long-term doxazosin treatment may result in only slight daytime hypotension with apparent nighttime tachycardia in normotensive subjects.

To investigate chronic immune effects of polychlorinated biphenyl (PCB) and polychlorinated dibenzofuran (PCDF), in vitro lymphocyte transformation in response to phytohemagglutinin (PHA) and concanavalin A (Con A) was studied in 139 patients with Yusho and 61 controls. PHA-induced lymphocyte transformation was significantly lower in patients with Yusho than in controls. PHA-induced lymphocyte transformation was inversely correlated with the concentrations of PCB and 2, 3, 4, 7, 8-pentachlorodibenzofuran (PeCDF) in the blood. Con A-induced lymphocyte transformation showed similar inverse correlations with the concentrations of PCB and 2, 3, 4, 7, 8-PeCDF. We conclude that impairment of mitogen-induced lymphocyte transformation in patients with Yusho may be associated with PCB and 2,3,4,7,8-PeCDF in the blood.

The possible formation of antihydrogen atoms via the collision of metastable antiprotonic helium atoms with positrons and positroniums is discussed based on the known behavior of positrons in helium media.

The lifetime and the intensity of ortho-positronium (o-Ps), τ3 and I3 respectively, were measured for polyimides and non-imide polymers in glassy state. Average size of free space holes probed by o-Ps, vh,Ps is calculated from τ3 using an empirical equation. Correlations between sorption of CO2 and the positron annihilation (PA) properties are discussed. The Langmuir capacity constant CH′ of the dual-mode sorption model is well correlated with vh,Ps, suggesting that the larger vh,Ps, reflects the higher volume fraction of holes large enough to be available for the Langmuir type sorption. The Henry’s law solubility constant kD is also correlated with vh,Ps, indicating that the polymers packed less-efficiently tend to have larger kD. As a result, there is a tendency that solubility coefficient of CO2 at 10 atm, SCO2, increases with vh,Ps. The CH′, kD, and SCO2, are also correlated with vh,PsI3 for only the polyimides, and the correlations are a little worse than those with vh,Ps.

A reactor-neutron-induced prompt γ-ray analyzing system was constructed at JRR-3M. The system can be set at cold and thermal neutron beam guides with a neutron flux at the sample position of 1.1 × 10 8 and 2.4 × 10 7 n cm −2 s −1 , respectively. The system was designed to achieve the lowest γ-ray background. This is done by using lithium fluoride tiles as neutron shielding, by placing the samples in a He atmosphere, and by using a Ge-BGO detector system for Compton suppression. The γ-ray spectrometer is equipped to acquire three modes of spectra simultaneously: single mode, Compton suppression mode, and pair mode in an energy range of up to 12 MeV. Due to the cold neutron guide beam and the low background system, sensitivities and detection limits better than those in other PGA systems have been achieved. For typical elements such as H, B, Cd, and Gd, analytical sensitivities with the cold neutrons are 10 to 18 times higher, and detection limits are lowered by factor of 6 to 8, compared to the case with thermal neutrons under the same geometrical condition. Detection limits down to a range of 2 to 7 ng were recorded for B, Cd, Sm, and Gd by the cold neutrons. Hydrogen, one of the most important elements in material studies, could be detected down to 1.0 and 2.8 μg by cold and thermal neutrons, respectively.

Positron lifetime measurements were performed for two different kinds of polymers (low density polyethylene and a polyimide 6FDA-TMPD) during sorption of various vapors (hexane, cyclohexane, benzen...

Positronium (Ps) formation in various polyimides has been studied. It has been found that Ps yield is zero or small in the polyimides having pyromellitic dianhydride (PMDA) and 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) as acid anhydride moiety, while those having 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) form Ps with intensities up to about 20%. This difference is well correlated with the electron affinity of these moieties: PMDA > BTDA > BPDA ∼ 6FDA. In another experiment o-Ps yields and its lifetimes were measured in benzene solutions of monomeric model compounds (imide compounds prepared from n-butylamine and the acid anhydrides). It has been found that the model compounds from PMDA and BTDA both inhibit Ps formation and quench o-Ps lifetimes but that those from BPDA and 6FDA have neither the inhibition nor the quenching effects. The results show that the spur model is applicable for Ps formation in the polyimides.

Correlation between Positron Annihilation and Gas Diffusion Properties of Various Rubbery Polymers

The foreskins of phimosis in children have been retracted as much as possible at the out-patient clinic, to avoid unnecessary operations. Five-hundred and twenty-seven cases of phimosis were experienced since 1986, and 427 of them were classified into 6 types according to the appearance of the penis and preputial orifice; type I (burried penis, 22 cases), type II (bottle neck, 86), type III (pinhole, 60), type IV (moderate stenosis, 154), type V (mild stenosis, 101), and type VI (scarred stenosis, 4). The foreskins were unable to retract in 13 cases (59.1%) of type I, 17 cases (19.8%) of type II, and 2 cases (50%) of type VI. In all cases of pinhole type, which looked highly stenotic, the foreskins were retractable. As a result, operation was performed only in 32 cases (6.1%) of all cases. Our best effort to retract the foreskin has reduced the operative indications of phimosis markedly.

Stimulatory effects of HSR-803 on intestinal motor activity in vitro were studied in guinea pig ileum. HSR-803 (1 x 10(-6)-1 x 10(-4) M) increased the amplitude of longitudinal muscle contractions and increased the frequency of peristalsis in isolated segments of guinea pig ileum. The stimulatory effect in amplitude and not frequency was abolished by 1 x 10(-6) M atropine. In the Magnus method with ileal segments, HSR-803 (1 x 10(-7) - 1 x 10(-4) M) produced contractions concentration-dependently, which were inhibited by atropine (1 x 10(-8) and 3 x 10(-8) M) and 3 x 10(-7) M tetrodotoxin (TTX). In the [3H]-quinuclidinyl benzilate (QNB) binding experiment with ileal smooth muscle, HSR-803 had low affinity for acetylcholine (ACh) receptors (pKi = 4.47 +/- 0.04). In addition, HSR-803 failed to increase the spontaneous release and the electrical stimulation-induced [3H]ACh release in ileal smooth muscle. On the other hand, HSR-803 (1 x 10(-5) M) enhanced contractions induced by ACh, but had no effect on contractions induced by carbachol, which is not hydrolyzed by acetylcholinesterase (AChE). In conclusion, HSR-803 stimulated ileal motor activity. However, HSR-803 had low affinity for ACh receptors and had no influence on ACh release. It is likely that HSR-803 stimulated motor activity mainly due to prevention of ACh hydrolysis.

70羽の脊髄損傷家兎を作成して,35羽について尿路系の変化を病理組織学的に検索した.(1)膀胱では経過とともに壁内炎症が高度となり,壁および筋層の肥厚が認められた.(2)尿管は6週以降で拡張を呈した.(3)腎臓では慢性腎盂腎炎,軽度水腎症がみられ,逆流性腎症を示唆する像も認められた.その他6ヵ月後では腎糸球体内にアミロイドの沈着がみられた.これらの病理学的所見は脊髄損傷により惹起されたもので,臨床の場で経験する脊髄障害の病態を知る手掛かりになるものと思われた.

The application of μ+ science, collectively called μSR, but encompassing a variety of methods including muon spin rotation, muon spin relaxation, muon spin repolarization, muon spin resonance and level-crossing resonance, to chemistry is introduced emphasizing the special aspects of processes which are “induced and probed” by the μ+ itself. After giving a general introduction to the nature and methods of muon science and a short history of muon chemistry, selected topics are given. One concerns the usefulness of muonium as hydrogen-like probes of chemical reactions taking polymerization of vinyl monomers and reaction with thiosulphate as examples. Probing solitons in polyacetylene induced and probed by μ+ is also an important example which shows the unique nature of muonium. Another important topic is “lost polarization”. Although this term is particular to muon chemistry, the chemistry underlining the phenomenon of lost polarization has an importance to both radiation and hot atom chemistries.

In order to find new antiasthmatic and antithrombotic agents, various [[1-aryl(or benzyl)-1-(benzenesulfonamido)methyl]phenyl]alkanoic acid derivatives were synthesized. Evaluation of these compounds for thromboxane A2 (TXA2) antagonistic activities indicated that 4-[4-[(4-chlorobenzenesulfonamido)phenylmethyl]phenyl]butyric acid (6h) ,4-[4-[1-(4-chlorobenzenesulfonamido)-2-phenylethyl]phenyl]butyric acid (6y) and many other compounds have potent inhibitory effects on U-46619-induced guinea-pig platelet aggregation. No significant difference in the inhibitory effect between (+)-6h and its antipode could be detected, although (+)-6h and its antipode could be detected, although (+)-6y was about 10 times more potent than (-)6y. The pKb values of 6h and 6y were estimated to be 8.9 and 10, respectively on U-46619-induced contraction of guinea-pig trachea as a pharmacological measure of TXA2 antagonistic activity. These compounds also showed potent inhibitory effects on U-46619-induced bronchoconstriction in guinea-pig after oral administration in vivo. They were also evaluated for other related pharmacological effects involving the arachidonic acid cascade. It was found that these compounds possess TXA2 synthase inhibitory activity together with TXA2 antagonistic activity, and 6h also possesses weak leukotriene D4 (LTD4) antagonistic activity. Structure-activity relationships for TXA2 antagonistic activity of these derivatives are discussed.

Study design A retrospective study. Objective We assessed risk factors for lumbosacral plexus palsy related to pelvic fracture that can be evaluated during the acute injury phase with diagnostics such as computed tomography (CT). Summary of background data Many patients with pelvic fracture are in vital shock, with polytrauma and loss of consciousness, making an accurate neurologic examination very difficult in the emergency room. Methods This study included 22 patients who had AO classification type B or C pelvic fractures. The 22 patients had 27 posterior osteoligamentary lesions. The average injury severity score (ISS) was 27.5 (range, 16-50). Age, sex, ISS, suicidal jump, longitudinal displacement, sacral transverse fracture, pubic fracture, lumbar transverse process fracture, type of pelvic fracture (AO), and type of sacral fracture (Denis) were examined for a correlation with the lumbosacral plexus palsy. Using coronal reconstruction CT, we considered a 10 mm or greater displacement at the sacrum or sacroiliac joint to be a longitudinal displacement. Transverse sacral fracture was diagnosed by sagittal reconstruction CT. Results Of the 22 patients, 5 (22.7%) had lumbosacral plexus palsy (8 of 27 pelvic fractures) detected during treatment. The incidence of lumbosacral plexus palsy was not related to age, sex, ISS. Incidence of palsy was significantly higher when the patient's affected side had longitudinal displacement. Patients who had made a suicidal jump or had a sacral transverse fracture also had a significantly higher risk for lumbosacral plexus palsy. Palsy was not related to the type of pelvic fracture (AO) or sacral fracture (Denis). Conclusion In this study, longitudinal displacement of the pelvis, transverse sacral fracture, and trauma from a suicidal jump were risk factors for lumbosacral plexus palsy. These risk factors were helpful in our examination of patients who had severe pelvic fracture with loss of consciousness.

Voltage-dependent Ca(2+) channels have been divided into at least 5 types (L-, N-, T-, P-, and Q-type). L/N-type Ca(2+) channel blocker cilnidipine could reduce the size of cerebral infarction in the rat focal brain ischemia. L-type Ca(2+) channel blocker amlodipine reduced cerebral edema and inhibit neuronal cell death. N-type Ca(2+) channel blocker omega-conotoxin reduce the size of cerebral infarction and inhibit delayed neuronal cell death in hippocampal CA1 area. It is suggested that calcium antagonist has neuroprotective effect.