Non-destructive elemental analysis of large meteorite samples by prompt gamma-ray neutron activation analysis with the internal mono-standard method.

Prompt gamma-ray neutron activation analysis (PGNAA) using the internal mono-standard method was tested for its applicability to analyzing large solid samples including irregularly shaped meteorite samples. For evaluating the accuracy and precision of the method, large quantities of the Geological Survey of Japan standardized rock powders (JB-1a, JG-1a, and JP-1) were analyzed and 12 elements (B, Na, Mg, Al, Cl, K, Ca, Ti, Mn, Fe, Sm, and Gd) were determined by using Si as an internal standard element. Analytical results were mostly in agreement with literature values within 10 %. The precision of the method was also shown to be within 10 % (1σ) for most of these elements. The analytical procedure was then applied to four stony meteorites (Allende, Kimble County, Leedey, Lake Labyrinth) and four iron meteorites (Canyon Diablo, Toluca (Mexico), Toluca (Xiquipilco), Squaw Creek) consisting of large chunks or single slabs. For stony meteorites, major elements (Mg, Al, Si, S, Ca, and Ni), minor elements (Na and Mn) and trace element (B, Cl, K, Ti, Co, and Sm) were determined with adequate accuracy. For iron meteorites, results for the Co and Ni mass fractions determined are all consistent with corresponding literature values. After the analysis, it was confirmed that the residual radioactivity remaining in the sample after PGNAA was very low and decreased down to the background level. This study shows that PGNAA with the internal mono-standard method is highly practical for determining the elemental composition of large, irregularly shaped solid samples including meteorites.

Neutron activation analysis of a particle returned from asteroid Itokawa.

A single grain (~3 micrograms) returned by the Hayabusa spacecraft was analyzed by neutron activation analysis. This grain is mainly composed of olivine with minor amounts of plagioclase, troilite, and metal. Our results establish that the Itokawa sample has similar chemical characteristics (iron/scandium and nickel/cobalt ratios) to chondrites, confirming that this grain is extraterrestrial in origin and has primitive chemical compositions. Estimated iridium/nickel and iridium/cobalt ratios for metal in the Itokawa samples are about five times lower than CI carbonaceous chondrite values. A similar depletion of iridium was observed in chondrule metals of ordinary chondrites. These metals must have condensed from the nebular where refractory siderophile elements already condensed and were segregated.

Determination of toxic trace elements in foodstuffs, soils and sediments of bangladesh using instrumental neutron activation analysis technique.

The concentrations of arsenic (As), chromium (Cr) and iron (Fe) were determined in the foodstuffs, soils and sediments from various areas in Bangladesh and new data for these toxic trace elements were given. The arsenic pollution problems in the most of the areas of Bangladesh are of geological origin. The high level of As in foodstuffs, soils and sediments, except for tannery sediments is probably positively correlated to the Fe concentration. An excessive amount of chromium was found in the sediments from the tannery area of Bangladesh.

Experimental identification of spin-parities and single-particle configurations in 257No and its alpha-decay daughter 253Fm.

alpha-gamma and alpha-electron coincidence spectroscopy for a short-lived heavy actinide nucleus (257)No (T(1/2) = 24.5 s) has been performed using a gas-jet transport system and an on-line isotope separator. Spin-parities of excited states in (253)Fm fed by the alpha decay of (257)No have been identified on the basis of the measured internal conversion coefficients. The nu3/2(+)[622] configuration has been assigned to the ground state of (257)No as well as to the 124.1 keV level in (253)Fm. It was found that the ground-state configuration of (257)No is different from that of lighter N = 155 isotones.

Purification and characterization of a NAD+-dependent sorbitol dehydrogenase from Japanese pear fruit.

NAD+-dependent sorbitol dehydrogenase NAD-SDH, EC 1.1.1.14) from Japanese pear fruit was purified to apparent homogeneity (single band by SDS-PAGE with silver staining), and had a specific activity of 916.7 nKatal/mg protein. The molecular of the native enzyme was calculated to be 160 kDa by gel filtration, whereas SDS-PAGE gave a subunit size of 40 kDa, indicating that the native enzyme is a homotetramer. The protein immunologically reacted with an antibody raised in rabbit against the fusion protein expressed in E. coli harboring an apple NAD-SDH cDNA. The Km, values for sorbitol and fructose were 96.4+/-8.60 and 4239+/-33.5 mM, respectively, and optimum pH for sorbitol oxidation was 9.0 and 7.0 for fructose reduction. Pear NAD-SDH had a very narrow substrate specificity, that is, sorbitol, L-iditol, xylitol and L-threitol were oxidized but not any of the other alcohols tested. These data suggest the structural importance of an S configuration at C-2 and an R configuration at C-4 in the substrate(s). Its enzymatic activity was strongly inhibited both by heavy metal ions such as mercury, and by thiol compounds, such as L-cysteine. However, the addition of zinc ion reversed the enzyme inactivation caused by addition of L-cysteine.

The strategy for internal carotid stenosis with thrombus.

SUMMARY: We report 3 cases of internal carotid artery (ICA) stenosis with thrombus. The initial symptom is transient ischemic attack (TIA) in 1 case, and cerebral infarction due to artery-to-artery embolism in 2 cases.We started anticoagulation and antiplatelet therapy after the angiography on admission in all cases. Carotid endarterectomy (CEA) was performed in 1 case after confirming the disappearance of the thrombus 1 month after the initial attack, although small cerebral embolic infarction happened during this period. In the other cases, percutaneous transluminal angioplasty (PTA) and stenting was performed using the protective technique about 2 weeks after the initial attack without embolic complication. Postoperative angiography showed sufficient dilatation. It seemed that PTA/stenting using the protection system was one of the alternatives for ICA stenosis with thrombus.

[Construct validity of a new computer-assisted cognitive assessment battery in normal adults].

A computer-assisted battery for neuropsychological tests (CNT) has been designed to screen adults for cognitive impairment. The aim of this study was to gather evidence for the construct validity of CNT and also investigate the relationship between CNT and conventional neuropsychological tests. Subjects were 45 healthy adults (21 men and 24 women), who ranged in age from 20 to 70 years (mean = 33.5, SD = 1.9) with no history of substance abuse, or of psychotic or neurological disorders. The CNT in our study consists of six subtests designed to assess various components of driving, such as digit span, visual scanning, visual and verbal memory, complex reaction time, and vigilance. Mini-mental state test, Kana-hiroi test, word fluency, the auditory-verbal learning test and Raven's colored progressive matrices were also performed as conventional neuropsychological tests. Results showed there were high correlations between each CNT subtests and conventional neuropsychological tests. A factor analysis (with varimax rotation) identified 4 factors with eigen values greater than 1, which accounted for over 70% of the variance. CNT was able to estimate each factor related to cognitive function such as learning and memory, attention, judgment, and visual scanning selectively. CNT may thus be a useful tool for detection of cognitive impairment, although this test has important limitations. Broader applications of these tests will require extensive population-based validation.

Cloning of NAD-dependent sorbitol dehydrogenase from apple fruit and gene expression.

Partial amino acid sequences of NAD-dependent sorbitol dehydrogenase (NAD-SDH) were used to identify a full-length cDNA from apple fruit. This clone consisted of 1,433 bp containing an open reading frame of 1,137 bp that could code for a polypeptide with 379 amino acids. To our knowledge, this is the first report about cloning of NAD-SDH cDNA from a plant source. The deduced amino acids from cDNA revealed 43.7% identity to human NAD-SDH. The activity of this enzyme to convert sorbitol to fructose with the reduction of NAD was certified by the fusion protein of this clone expressed in Escherichia coli. Northern blot analysis showed that the mRNA was expressed in matured apple fruit.

Correlation between bleeding time and antithrombotic effect of platelet-suppressive agents in rat experimental model.

To examine whether the dosage of a platelet-suppressive agent at which an antithrombotic effect is adequate and bleeding tendency is not increased can be found, the antithrombotic effects, antiplatelet effects and bleeding times of ticlopidine and aspirin were investigated in the rat experimental thrombus formation model. Thrombus formation was determined by measuring the change in wet weight of a silk thread placed in a carotid arteriovenous shunt. Ticlopidine inhibited thrombus formation and platelet aggregation at rather low doses (50-100 mg/kg) without prolonging bleeding time. However, aspirin did not inhibit thrombus formation at even the highest examined dose (200 mg/kg), while bleeding time was prolonged at even the lowest dose (50 mg/kg). These results suggest that a dosage of antithrombotic agent that does not increase bleeding tendency can be easily established using ticlopidine, although it is relatively difficult using aspirin.

[The effects of platelet-activating factor (PAF) on the collagen-induced whole blood aggregation].

The role of platelet-activating factor (PAF) on collagen-induced whole blood aggregation was studied. First, the collagen-induced whole blood aggregation was examined using impedance aggregometry. Even if whole blood was pretreated with both acetylsalicylic acid (aspirin, ASA) and CP/CPK (creatine phosphate and creatine phosphokinase) to inhibit arachidonic acid metabolites products in the cyclooxygenase pathway and ADP, whole blood aggregation was induced by collagen in a concentration-dependent manner. This suggest that other factors, including PAF, led to this aggregation. Even though addition of CV3988 (specific PAF inhibitor) with ASA and CP/CPK had no further effect on collagen-induced whole blood aggregation, collagen-induced whole blood aggregation was significantly reduced in whole blood pretreated with CV3988 or ASA alone; but not with CP/CPK alone. Next, synthesized PAF from washed platelets or washed leukocytes stimulated with collagen or ONO-11113 (STA2; stable analogue of thromboxane A2), and the inhibiting effects of ASA on the PAF synthesis from collagen-stimulated leukocytes were examined, using a radioimmunoassay kit for PAF. Collagen stimulated the leukocytes PAF synthesis but not the platelets PAF synthesis. STA2 also stimulated leukocytes PAF synthesis. ASA pretreatment of leukocytes significantly reduced the collagen-induced PAF synthesis. Thus, PAF seemed to affect collagen-induced whole blood aggregation and ASA seemed to inhibit PAF synthesis. From these results, I conclude PAF (synthesized from leukocytes directly stimulated with collagen or indirectly with thromboxane A2 from collagen-stimulated platelets) plays an important role in collagen-induced whole blood aggregation.

Inhibitory effect of staphylokinase on platelet aggregation.

We investigated the effect of staphylokinase (SAK), which has specific thrombolytic properties, on human platelet aggregation. Platelet aggregation induced with collagen was observed following preincubation of platelets in platelet-rich plasma (PRP) or washed platelet suspension (WP) with SAK at 37 degrees C for 30 min. SAK inhibited platelet aggregation in PRP only at the highest examined concentration (1 x 10(-4) g/ml). Although SAK did not inhibit platelet aggregation in WP which contained fibrinogen, it did when the platelets had been preincubated with SAK and plasminogen. The most effective concentration in WP was 1 x 10(-6) g/ml. The effect could be inhibited by adding aprotinin or alpha 2-antiplasmin. The highest generation of plasmin in the same preincubation fluid was detected at 1 x 10(-6) g/ml SAK. We concluded that SAK can inhibit platelet aggregation in WP by generating plasmin and/or fibrinogen degradation products, but is only partially effective in PRP because of the existence of alpha 2-antiplasmin.

Inhibitory effect of vitamin E (alpha-tocopherol) on spontaneous platelet aggregation in whole blood.

Vitamin E (D-alpha-tocopherol) inhibited spontaneous human platelet aggregation in whole blood in the 20-200 micrograms/ml range. When alpha-tocopherol (20 micrograms/ml) and aspirin (0.5 mM), or alpha-tocopherol and the mixture of phosphocreatine (1.5 mM) and creatine phosphokinase (50 U/ml) (CP/CPK) were added to this reaction system, a synergic inhibitory effect on aggregation was observed. On the other hand, when both alpha-tocopherol and the specific inhibitor of platelet activating factor (CV-3988; 0.38 mM) were added to this system, the inhibition was the same as that caused by the addition of CV-3988 alone, suggesting there was no synergism, i.e., that the effect of alpha-tocopherol is related to the inhibition of platelet activating factor (PAF)-induced platelet aggregation in whole blood. However, alpha-tocopherol (20 or 50 micrograms/ml) did not inhibit PAF (10 nM) induced platelet aggregation in platelet rich plasma (PRP). These results suggest that the inhibition of platelet aggregation in whole blood by alpha-tocopherol is due to the inhibition of PAF synthesis, and is unrelated to adenosine diphosphate (ADP) or thromboxane A2.

Fibrinogenolysis in thrombotic thrombocytopenic purpura.

Coagulo-fibrinolytic factors were studied in five patients suffering from thrombotic thrombocytopenic purpura (TTP). The change in coagulation factors in the acute stage was mild compared with that found in disseminated intravascular coagulation (DIC). We observed a slight increase of fibrin-fibrinogen degradation products (FDP) in the plasma of four patients during the acute stage of TTP, but the level of the D-dimer remained within normal variation and was extremely low compared with that in 27 samples from patients with DIC showing the same level of FDP. At the same time, both antigen levels of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) were elevated in three of the four patients tested. Although a similar change was recognized in DIC patients' plasma, the elevation of PAI-1 in the acute stage of TTP was far higher than in overt DIC. The antigen levels of t-PA and PAI-1 were normal in remission, and a mild elevation of PAI-1 was detected in one of the three patients during the early stage of TTP relapse. Enzymography revealed the appearance of free t-PA and an increase of a substance with a 110 kD molecule, assumed to be a t-PA and PAI-1 complex, in TTP plasma in the acute stage, but the findings were normal for plasma from cases in remission and the early stage of relapse. Enzymography also showed a decrease of urokinase-type plasminogen activator (u-PA) only in the acute stage of TTP. These changes in the coagulo-fibrinolytic factors in the acute stage of TTP suggest that fibrinogenolysis might be induced by t-PA, released through vascular reaction at an uninvolved area of vascular lesions caused by platelet agglutinates, which would then release large amounts of PAI-1 inhibiting t-PA and u-PA activities at the occlusive lesion.

[Clinical significance of cross linked fibrin degradation products in thrombotic disorders].

We performed a clinical study by measuring the plasma levels of D-dimer, which is derived from the degradation of cross linked fibrin, in some thrombotic disorders using Dimertest EIA kit obtained from AGEN Corp. (Australia). The level of D-dimer in disseminated intravascular coagulation (DIC) were greater than that in thrombotic thrombocytopenic purpura (TTP). These levels of D-dimer in two thrombotic disorders showed a different pathogenesis between them. And also, the levels of D-dimer in some arteriosclerotic disorders, i.e.; aortic aneurysm , cerebral infarction and coronary insufficiency, and in venous thrombosis significantly increased compared with normal subjects. The level of D-dimer measured by Dimertest EIA kit was useful marker for detecting a thrombotic tendency in the low level of D-dimer, in which latex agglutination test for fibrin/fibrinogen degradation products (FDPL test) could not usually detect.

Successful delivery in a female with thrombotic thrombocytopenic purpura.

A 28-year-old female, who suffered from thrombotic thrombocytopenic purpura (TTP) in the 14th week of her first pregnancy, recovered after a plasma exchange followed by an induced abortion. From six months after the abortion, she no longer required plasma infusions every 3-4 weeks to prevent a relapse of TTP manifested as thrombocytopenia, and complete remission continued until her next pregnancy. In her second pregnancy, she had an immediate relapse of TTP and responded to plasma infusion until the 24th week. However, the TTP gradually became resistant to plasma infusion, and developed into toxemia with edema, hypertension and proteinuria in the 27th week. Although the TTP was alleviated by the infusion of large amounts of plasma, the placenta failed as the result of numerous white infarcts. She delivered a 948 g live baby by cesarean section in the 33rd week. The baby had transient thrombocytopenia but did not suffer from TTP. The mother required plasma infusions every 3-4 weeks for about five months, and she has continued in remission.