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GRB 021004 is one of the best sampled gamma-ray bursts (GRB) to date, although the nature of its light curve is still being debated. Here we present 107 new optical, near-infrared (NIR) and millimetre observations, ranging from 2 h to more than a year after the burst. Fitting the multiband data to a model based on multiple energy injections suggests that at least 7 refreshed shocks took place during the evolution of the afterglow, implying a total energy release (collimated within an angle of 1$\fdg$8) of ~$8 \times 10^{51}$erg. Analysis of the late photometry reveals that the GRB 021004 host is a low extinction ($A_{\rm V}\sim0.1$) starburst galaxy with $M_{B}\simeq-22.0$.

We report a measurement of the shape of the source star in microlensing event MOA 2002-BLG-33. The lens for this event was a close binary whose centre-of-mass passed almost directly in front of the source star. At this time, the source star was closely bounded on all sides by a caustic of the lens. This allowed the oblateness of the source star to be constrained. We found that $a/b = 1.02^{+0.04}_{-0.02}$where aand bare its semi-major and semi-minor axes respectively. The angular resolution of this measurement is approximately 0.04 $\mu\rm{arcsec}$. We also report HST images of the event that confirm a previous identification of the source star as an F8-G2 turn-off main-sequence star.

We report a measurement of limb darkening of a solar-like star in the very high magnification microlensing event MOA 2002–BLG–33. A 15 hour deviation from the light curve profile expected for a single lens was monitored intensively in Vand Ipassbands by five telescopes spanning the globe. Our modelling of the light curve showed the lens to be a close binary system whose centre-of-mass passed almost directly in front of the source star. The source star was identified as an F8–G2 main sequence turn-off star. The measured stellar profiles agree with current stellar atmosphere theory to within ~4% in two passbands. The effective angular resolution of the measurements is <1 μas. These are the first limb darkening measurements obtained by microlensing for a Solar-like star.

The feasibility for the lead-bismuth-cooled accelerator-driven system (ADS) to transmute minor actinides partitioned from high-level radioactive waste is discussed. Since lead-bismuth will cause considerable corrosion and erosion effects at high temperature, the fuel-clad temperature must be kept as low as possible. Moreover, the most critical issue of the ADS design is the engineering viability of the high-power spallation target and the beam window. The thermal-hydraulic and structural analysis was carried out for both the fuel assembly and the beam window. In addition to the analysis in steady state, the transient behaviors were also studied during typical transient and unprotected accidents. The results showed that engineering viability is reasonably achievable in the nominal operation. For the beam trip, which will be the most frequent transient, the number of events to cause the failure of the beam window is estimated as more than 105. For safety aspects of the ADS during unprotected accidents, the estimated results showed that unprotected loss of flow would cause the most significant problem, if the beam operation was kept. Therefore, high reliability of the beam shutdown is required for the ADS safety.

Background: We proposed diagnostic criteria for immune thrombocytopenic purpura (ITP) by modifying the existing guidelines for diagnosis of ITP and by incorporating laboratory tests found useful for predicting its diagnosis, for example erythrocyte count, leukocyte count, anti‐GPIIb/IIIa antibody‐producing B cells, platelet‐associated anti‐GPIIb/IIIa antibodies, percentage of reticulated platelets, and plasma thrombopoietin. Objective and methods: To validate our criteria, we conducted a multi‐center prospective study involving 112 patients with thrombocytopenia and a morphologically normal peripheral blood film at the first visit. Each patient underwent a physical examination, routine laboratory tests, and specialized tests for the anti‐GPIIb/IIIa antibody response and platelet turnover. Results: Ninety‐one patients (81%) satisfied the proposed criteria at first visit. Clinical diagnosis was made by skilled hematologists > 6 months after the first visit; ITP was diagnosed in 88 patients and non‐ITP disorders in 24. The proposed criteria had 98% sensitivity, 79% specificity, a 95% positive predictive value, and a 90% negative predictive value. A relatively low specificity appears to be attributed to a few patients who had both ITP and aplastic anemia or myelodysplastic syndrome. Conclusions: Our preliminary diagnostic criteria based on ITP‐associated laboratory findings were useful for the differential diagnosis of ITP, but additional evaluations and modifications will be necessary to develop criteria that can be used routinely.

Objective: Platelet integrin αIIbβ3plays a crucial role in platelet aggregation, and the affinity of αIIbβ3for fibrinogen is dynamically regulated. Employing modified ligand‐binding assays, we analyzed the mechanism by which αIIbβ3maintains its high‐affinity state. Methods and results: Washed platelets adjusted to 50 × 103 μL−1were stimulated with 0.2 U mL−1thrombin or 5 μmU46619 under static conditions. After the completion of αIIbβ3activation and granule secretion, different kinds of antagonists were added to the activated platelets. The activated αIIbβ3was then detected by fluorescein isothiocyanate (FITC)‐labeled PAC1. The addition of 1 μmAR‐C69931MX (a P2Y12antagonist) or 1 mmA3P5P (a P2Y1antagonist) disrupted the sustained αIIbβ3activation by ∼92% and ∼38%, respectively, without inhibiting CD62P or CD63 expression. Dilution of the platelet preparation to 500 μL−1also disrupted the sustained αIIbβ3activation, and the disruption by such dilution was abrogated by the addition of exogenous adenosine 5′‐diphosphate (ADP) in a dose‐dependent fashion. The amounts of ADP released from activated platelets determined by high‐performance liquid chromatography were compatible with the amounts of exogenous ADP required for the restoration. We next examined the effects of antagonists on protein kinase C (PKC) and Rap1B activation induced by 0.2 U mL−1thrombin. Thrombin induced long‐lasting PKC and Rap1B activation. AR‐C69931MX markedly inhibited Rap1B activation without inhibiting PKC activation. Conclusions: Our data indicate that the continuous interaction between released ADP and P2Y12is critical for the maintenance of αIIbβ3activation.

In this study, we have identified a patient (OSP-1) with a congenital P2Y12deficiency showing a mild bleeding tendency from her childhood and examined the role of P2Y12in platelet function. At low concentrations of agonists OSP-1 platelets showed an impaired aggregation to several kinds of stimuli, whereas at high concentrations they showed a specifically impaired platelet aggregation to adenosine diphosphate (ADP). ADP normally induced platelet shape change and failed to inhibit PGE1-stimulated cAMP accumulation in OSP-1 platelets. Molecular genetic analysis revealed that OSP-1 was a homozygous for a mutation in the translation initiation codon (ATG to AGG) in the P2Y12gene. Heterologous cell expression of wild-type or mutant P2Y12confirmed that the mutation was responsible for the deficiency in P2Y12. OSP-1 platelets showed a markedly impaired platelet spreading onto immobilized fibrinogen. Real-time observations of thrombogenesis under a high shear rate (2000 s−1) revealed that thrombi over collagen were small and loosely packed and most of the aggregates were unable to resist against high shear stress in OSP-1. Our data suggest that secretion of endogenous ADP and subsequent P2Y12-mediated signaling are critical for platelet aggregation, platelet spreading, and as a consequence, for stabilization of thrombus.

WAVE isoforms, which consist of WAVE‐1, WAVE‐2 and WAVE‐3, are members of the Wiskott–Aldrich syndrome protein (WASP) family. They are implicated in the regulation of actin‐cytoskeletal reorganization downsteam of the small GTPase, Rac. Since platelet attachment to extracellular matrices leads to filopodial and lamellipodial extension, we examined the expression and subcellular localization of WAVEs in platelets. Employing primary megakaryocytic cells derived from cord blood as well as megakaryocytic cell lines, we also examined their expression during megakaryocytic differentiation. Immunoblotting and immunohistochemical analysis revealed that platelets expressed WAVE‐1 and WAVE‐2, whereas WAVE‐3 expression was hardly to be detected. WAVE‐1 expression was associated with megakaryocytic differentiation, whereas WAVE‐2 and WAVE‐3 expression was not changed by the differentiation. In adhered platelets both WAVE‐1 and WAVE‐2 were localized at the edge of the lamellipodia and at the tips of filopodia. In WASP‐deficient platelets we found normal lamellipodial formation and localization of WAVE‐1 and WAVE‐2 at the edges of lamellipodia. Furthermore, we demonstrated that WAVE‐1 and WAVE‐2 moved from a detergent‐soluble cytosolic fraction to insoluble cytoskeleton fraction after platelet aggregation. These results suggest that WAVE‐1 and WAVE‐2 regulate actin reorganization during platelet spreading and aggregate formation.

Affinity/avidity state of integrin αIIbβ3is regulated by intracellular inside‐out signaling. Although several megakaryocytic cell lines have been established, soluble ligand binding to αIIbβ3expressed in these cells by cellular agonists has not been demonstrated. We have re‐examined agonist‐induced αIIbβ3activation on megakaryocytic cell lines with a marker of the late stage of megakaryocytic differentiation, glycoprotein Ib (GPIb). Activation of αIIbβ3was assessed by PAC1 and soluble fibrinogen binding to the cells. We found that αIIbβ3expressed in CMK cells with high GPIb expression was activated by a phorbor ester, phorbol myristate acetate (PMA). Although the population of the GPIbhighcells was <0.5% of the total cells, incubation with a nucleoside analog, ribavirin, efficiently increased the PMA‐reactive GPIbhighcells. Not only PMA but also a calcium ionophore, A23187, induced αIIbβ3activation, and PMA and A23187 had an additive effect on αIIbβ3activation. Ligand binding to the activated αIIbβ3in the GPIbhighCMK cells is totally abolished by an αIIbβ3‐specific antagonist, and inhibited by wortmannin, cytochalasin‐D and prostaglandin E1, and the effects of these inhibitors on αIIbβ3activation in the GPIbhighCMK cells were compatible with those in platelets. We have also demonstrated that the ribavirin‐treated CMK cells express PKC‐α, ‐β, ‐δ and ‐θ, and suggested that PKC‐α and/or ‐β appear to be responsible for PMA‐induced activation of αIIbβ3in CMK cells.

We measured reticulated platelets (RPs) and plasma glycocalicin (GC) and thrombopoietin (TPO) levels simultaneously in 107 thrombocytopenic patients to clarify the diagnostic value of these tests for discriminating hyperdestructive from hypoplastic thrombocytopenia. The percentage of RPs and GC index (plasma GC level normalized for the individual platelet count) were markedly elevated in patients with idiopathic thrombocytopenic purpura (ITP) but normal or slightly elevated in patients with aplastic anemia (AA) or chemotherapy-induced thrombocytopenia (ChemoT). For RP percentage for diagnosing hyperdestructive thrombocytopenia the sensitivity and specificity were excellent but were lower for the GC index. Absolute RP counts and plasma GC levels were markedly decreased and plasma TPO levels markedly elevated in patients with AA or ChemoT, but absolute RP counts and plasma GC levels were moderately decreased and plasma TPO levels only slightly elevated in patients with ITP. The sensitivity and specificity of plasma TPO levels for diagnosing hypoplastic thrombocytopenia were excellent. Using the RP percentage and plasma TPO levels in combination improved specificities. Simultaneous measurement of RP percentage and plasma TPO level may help discriminate thrombocytopenia of unknown cause in routine hematologic practice.

In addition to post-irradiation creep tests, in-pile creep tests were performed using newly developed technology with in situ measurement under different neutron spectra. The in-pile creep properties of type 304 stainless steel at 550°C appear to depend on neutron spectrum, but a spectral effect on post-irradiation creep properties is not clearly seen. The rupture time of in-pile creep under a high thermal neutron flux condition is the shortest. The order of the rupture time following the high thermal flux condition is post-irradiation creep, in-pile creep with a thermal neutron shield condition and finally creep of unirradiated material, all in increasing order. It is suggested that the acceleration of creep deformation and fracture observed in irradiation creep tests may be related to enhancement of thermal creep in terms of FMD increased under a high thermal neutron flux in addition to increased helium embrittlement.

Male (NZW x BXSB) F1 (W/B F1) mice, which develop lupus nephritis, myocardial infarction, and thrombocytopenia, showed reduced platelet lifespan (PLS) and increased platelet-associated antibody (PAA) values. There were statistically significant correlations between the increase in PAA values and either the reduction in PLS or the decrease in platelet counts. This and the results of platelet transfer experiments between old male W/B F1 mice and either female W/B F1 or normal BALB/c mice indicate that PAAs on the platelet surface play a crucial role in the destruction of platelets in W/B F1 mice. The mechanism of thrombocytopenia observed here appears similar to that of human idiopathic thrombocytopenic purpura (ITP). Therefore, we think that W/B F1 mice are a potentially useful animal model for investigating the effectiveness and mode of action of therapeutic agents in human ITP, and that they may provide additional information on the basic mechanisms of this autoimmune phenomenon.

Hyaline droplet nephropathy in male rats due to α2u-globulin accumulation in proximal tubules is caused by chemicals from several chemical classes. We have previously shown that the well-known sedative/hypnotic barbiturate, sodium barbital, and its breakdown product, diethylacetylurea, are renal toxins and renal tumor promoters. To determine comparative induction of hyaline droplets in renal tubules by sodium barbital and diethylacetylurea, male F344/NCr rats, 6 weeks of age, were given diets containing 0, 170, 341, 500, or 1000 ppm of diethylacetylurea or containing 500, 1000, or 4000 ppm of sodium barbital for periods of 2 or 10 weeks. Rats were terminated at 2 or 10 weeks and the histology of the kidney was evaluated using light microscopy with hematoxylin and eosin staining and staining by the Heidenhain method. Quantitative analysis showed dose responses for the degree of droplet accumulation in the P2 and P3 segments of the proximal tubules. Diethylacetylurea was more potent. Immunohistochemistry and ultrastructural evaluation revealed the nature of the droplets. Western blotting confirmed the presence of α2u-globulin. Renal tubular necrosis, regeneration, and increased levels of cell proliferation using proliferating cell nuclear antigen immunohistochemistry were also found. Female rats similarly exposed to each chemical did not show tubule droplet accumulations nor renal lesions. We confirm for the first time that these two chemicals can be added to the enlarging list of nephrotoxic chemicals inducing α2u-globulin nephropathy and possessing tumor promoting and renal carcinogenic properties.Copyright 1994, 1999 Academic Press, Inc.

To determine the mechanism by which platelet counts increase after corticosteroid therapy for human immune thrombocytopenic purpura (ITP), we studied the platelet kinetics using prednisolone (PDN)-treated ITP- prone mice, (NZW x BXSB) F1 (W/B F1). An increase in platelet counts was observed in W/B F1 mice (n = 10, mean +/- SD, 1,202 +/- 202 x 10(3)/microL) 4 weeks after treatment with PDN (2 mg/kg/d); no increase occurred in nontreated W/B F1 mice (n = 5,651 +/- 126, P less than .005). Prolonged platelet life-spans (PLSs) were observed in treated W/B F1 mice (1.29 +/- 0.40 days), but not in nontreated controls (0.60 +/- 0.24 days, P less than .01). No increase in platelet production (platelet turnover) was found in PDN-treated W/B F1 mice, but significant decreases in platelet-associated antibodies (PAAs) and platelet-bindable serum antibodies (PBAs) were noted. Studies on organ localization of radiolabeled platelets showed that hepatic uptake significantly decreased in the treated W/B F1 mice, but not in nontreated W/B F1 mice. To elucidate the effect of PDN on the reticulo- endothelial phagocytic activity in W/B F1 mice, we studied in vivo clearance of IgG-sensitized, 51Cr-labeled autologous erythrocytes. W/B F1 mice treated with PDN showed a marked impairment of their ability to clear these cells, although PDN had little effect on the number of splenic or hepatic macrophage Fc gamma receptors. These results and our previous findings of splenectomy suggest that PDN improves platelet counts not only by suppressing systemic reticulo-endothelial phagocytic function but also by reducing antibody production.

Male (NZW x BXSB)F1 (W/BF1) mice develop systemic autoimmunity involving autoantibodies, thrombocytopenia, lupus nephritis, and coronary vascular disease with myocardial infarction (CVD). To determine whether this murine lupus-associated CVD could be transferred to otherwise autoimmune-resistant (C57BL/6 x C3H/He)F1 (B6C3F1) mice via W/BF1 T-cell-depleted marrow (TCDM) transplants, or conversely whether the CVD of W/BF1 mice could be prevented by the reciprocal transplant, reciprocal haploidentical transplants of TCDM were performed. CVD developed only in mice with systemic autoimmunity. Mice that developed lupus had glomerulonephritis and thrombocytopenia and also had elevated titres of autoantibodies to double-strand DNA, cardiolipin, and platelets and elevated levels of circulating immune complexes. Of control W/BF1 mice, 80% developed lupus, and of these, 81% developed CVD with a mean grade of 2.5 +/- 0.8. Engraftment of W/BF1 mice with B6C3F1 marrow protected 90% of the recipients from the development of lupus, and none developed CVD. Engraftment of B6C3F1 mice with W/BF1 marrow induced lupus in 60% of the recipients, and of those, 33% developed CVD with a mean grade of 1.3 +/- 0.3. The B6C3F1 recipients of W/BF1 marrow which developed CVD had significantly higher titres of autoantibodies to cardiolipin (aCL; P < .01). These findings show that genetic abnormalities present in the W/BF1 hematopoietic stem cells contribute to autoantibody development, including aCL, and suggest that thrombogenic mechanisms induced by aCL may contribute to the development of CVD in this form of murine lupus erythematosus.

We have characterized a murine IgG monoclonal antibody, OP-G2, specific for platelet glycoprotein (GP) IIb-IIIa (alpha IIb beta 3). OP-G2 Fab fragments inhibit fibrinogen-mediated platelet aggregation and competitively inhibit adenosine diphosphate-induced binding of 125I- fibrinogen to washed platelets. OP-G2 binding to GPIIb-IIIa is specifically inhibited by RGD-containing peptides but not the fibrinogen gamma-chain carboxy-terminal peptide, and OP-G2 Fab fragments, like RGD-containing peptides, alter the conformation of GPIIb-IIIa resulting in the expression of a ligand-induced binding site (LIBS) recognized by PMI-1. OP-G2 fails to bind to the recombinant Cam variant of GPIIb-IIIa (alpha III beta 3Cam) wherein an Asp119 to Tyr119 substitution in GPIIIa abrogates the ability to recognize RGD. These data indicate that OP-G2 recognizes an epitope at or in very close proximity to the RGD recognition site of GPIIb-IIIa and that, in every aspect tested, OP-G2 behaves like a macromolecular RGD ligand. Interestingly, two-color flow cytometry shows that OP-G2 IgG can bind to nonactivated platelets. Quantitative binding assays indicate that nonactivated platelets bind approximately 50,000 125I-OP-G2 molecules/platelet. Furthermore, the affinity of OP-G2 for platelets activated with thrombin is roughly fivefold higher (nonactivated, kd = 24.8 nmol/L; activated, kd = 4.9 nmol/L). These results suggest that the RGD recognition site of GPIIb-IIIa is available to macromolecules that contain RGD even on nonactivated platelets, provided that the affinity of the ligand is adequate.

In the present study, we have investigated the mechanism of affinity modulation of alpha IIb beta 3 by chymotrypsin. We first confirmed that alpha-chymotrypsin could activate alpha IIb beta 3 (approximately 7,000 molecules per platelet) without major intracellular signaling. However, we unexpectedly found that high concentrations of amiloride dose-dependently inhibited 125I-fibrinogen binding to the chymotrypsin-treated platelets, as well as the platelet aggregation (IC50 [50% inhibitory concentration] for fibrinogen binding, 530 mumol/L). In contrast, amiloride did not inhibit alpha IIb beta 3 activation induced by anti-alpha IIb beta 3 monoclonal antibody PT25–2 or AP5. To identify the pathway involved, the effects of alteration of Na+ gradient in platelets were examined. Lowering Na+ gradient by replacing extracellular Na+ with tetramethylammonium (TMA) increased the number of activated alpha IIb beta 3 by twofold, as assessed by fibrinogen-binding assay. The incubation of platelets with ouabain, a Na+/K(+)- adenosine triphosphatase (ATPase) inhibitor, further augmented alpha IIb beta 3 activation. These data suggested that a likely candidate for the pathway was Na+/Ca2+ exchanger. At 140 mmol/L [Na+]o, 45Ca2+ influx to the chymotrypsin-treated platelets was twofold greater than that to non-treated platelets. Replacement of Na+ with TMA further increased the Ca2+ influx, and the increase was inhibited by amiloride dose-dependently. 3′,4′-Dichlorobenzamil (DCB) and bepridil, relatively specific inhibitors of Na+/Ca2+ exchanger, also inhibited the chymotrypsin-induced alpha IIb beta 3 activation, and the IC50 values of these inhibitors for fibrinogen binding were 25 mumol/L and 52 mumol/L, respectively. Moreover, platelet aggregation induced by various physiologic agonists was inhibited by DCB or bepridil, while platelet agglutination by ristocetin was not. Our data newly suggest that Na+/Ca2+ exchanger operating in reverse mode may be directly involved in inside-out signaling that activates alpha IIb beta 3.

The present studies provide direct evidence that some patients with chronic immune thrombocytopenic purpura (ITP) have autoantibodies reactive with platelet glycoprotein Ib ( GPIb ). Microtiter wells coated with a monoclonal antibody that recognized GPIb were reacted with either platelet extract or a control cell extract. After washing and incubating with test plasma, well-bound IgG was quantitated using radioactive anti-IgG. When compared to plasma from normal subjects, plasma from 3 of 106 patients with chronic ITP had significantly increased quantities of IgG bound to microtiter wells reacted with platelet extracts. Negative results were obtained with the remaining 103 patients with chronic ITP and 59 patients with a variety of other platelet disorders. Plasma from two of the three positive patients precipitated a protein from 125I-surface-labeled platelet extract with a molecular weight similar to GPlb . One of the three patients with anti- GPlb antibody also had demonstrable autoantibodies to the platelet glycoprotein llb / llla complex.

The dependences on phosphorus doping of ESR, conductivity, X-ray diffraction and hydrogen vibrational spectra have been investigated for microcrystalline Si films prepared by a new glow-discharge decomposition method where the substrate is placed in a heated plasma gas. The results are compared with those for amorphous Si : H and polycrystalline Si films. A higher deposition rate of 80-160 Å min-1 and larger crystallite sizes of 150-250 Å have been found than in other methods of preparation. The morphology of an amorphous phase in the microcrystalline film is different from that in an amorphous Si : H film, and the width of the conduction band tail-states in the amorphous phase portion is considerably narrower. A large conductivity in the P-doped microcrystalline films is interpreted as arising from an enhanced upward shift of the Fermi level permitted by the reduction in the tail-state width. A strong correlation between the conductivity and hydrogen bonded in SiH2 groups was found, the conductivity being smaller in films with high hydrogen contents. The conductivity of microcrystalline films with low hydrogen contents is analysed in terms of a random mixture of crystallites and amorphous phase regions. From ESR measurements, the electron mobility in the crystallites was found to be similar to that in single-crystal Si.

We performed a molecular analysis of a subject whose platelets and monocytes did not express any cell surface CD36 (designated as a type I CD36 deficiency). Amplification of the 5' half of platelet and monocyte CD36cDNA (corresponding to nucleotide [nt] 191–1009 of the published CD36 cDNA sequence [Oquendo et al, Cell, 58:95, 1989]) showed that two different-sized CD36 cDNAs existed. One cDNA was of predicted normal size, whereas the other was about 150 bp smaller than that predicted for normal CD36 cDNA. Amplification of the 3' region of CD36 cDNA (nt 962–1714) in this subject showed only normal-sized CD36 cDNA. Cloning and nt sequence analysis of the cDNAs showed that the smaller sized CD36 cDNA had 161-bp deletion (from nt 331 to 491), and a dinucleotide deletion starting at nt position 539. The same dinucleotide deletion was also detected in the normal sized CD36 cDNA. Both deletions caused a frameshift leading to the appearance of a translation stop codon. RNA blot analysis and quantitative assay using the reverse transcription- polymerase chain reaction (RT-PCR) showed that the CD36 transcripts in both platelets and monocytes were greatly reduced. Comparison of the determined cDNA sequences with the genomic DNA sequence for the human CD36 gene showed that the dinucleotide deletion was located in exon 5, and that the 161-bp deletion corresponded to a loss of exon 4. PCR- based analysis using genomic DNA showed that this subject was homozygous for the dinucleotide deletion in exon 5. Except for the dinucleotide deletion, we could not find any abnormalities around exon 3, 4, and 5 including the splice junctions. These results suggested that the deletions in CD36 mRNA were likely to be responsible for instability of the transcripts, and the dinucleotide deletion in exon 5 might affect the splicing of exon 4.

Male (NZW x BXSB)F1 (W/BF1) mice develop systemic autoimmunity involving autoantibodies, progressive thrombocytopenia, lupus nephritis, and degenerative coronary vascular disease with myocardial infarction. Platelet-associated IgG (PAIgG) on the platelet surface mediates platelet destruction by the reticuloendothelial system in the autoimmune thrombocytopenic purpura (ATP) of W/BF1 mice. Because the epitopes targeted in ATP by PAIgG have not been identifiable using serum from thrombocytopenic W/BF1 mice, we developed seven hybridomas secreting antiplatelet monoclonal antibodies (MoAbs) using splenocytes of thrombocytopenic W/BF1 mice. Epitopes recognized by three MoAbs were similar to those recognized by PAIgG, because eluted IgG from platelets of thrombocytopenic W/BF1 mice inhibited platelet binding by MoAbs in competitive micro-enzyme-linked immunosorbent assay. Hybridoma cells or purified Ig from the ascites of two clones (2A12 and 6A6), when injected into nude mice produced acute thrombocytopenia, elevated the levels of PAIgG, purpura, and megakaryocytosis. MoAbs of two clones also reacted with single-stranded DNA or double-stranded DNA, and one of these clones (4–13) bound to cardiolipin (CL) but was nonpathogenic in nude mice, suggesting that anti-CL and antiplatelet autoantibodies can be distinct. On immunoblotting analysis, antiplatelet MoAbs frequently bound a 100-Kd platelet protein. These MoAbs contribute to an understanding of the etiopathogenesis of ATP and the several antigens and autoantibodies involved.

Neutropenia is frequently observed in a variety of autoimmune disorders. As the mechanism of neutropenia in these disorders, the destruction of neutrophils by anti-neutrophil autoantibodies has been believed since elevated levels of neutrophil-associated IgG (NAIgG) have been described. However, no data exists to characterize the nature of NAIgG and show NAIgG is an anti-neutrophil autoantibodies. We investigated whether the elevated NAIgG in these patients consists of anti-neutrophil autoantibodies. The NAIgGs of 91 patients with autoimmune disorders including 50 patients with idiopathic thrombocytopenic purpura, 13 patients with systemic lupus erythematosus, 11 patients with Hashimoto's thyroiditis and 10 patients with Graves' disease were analyzed. The level of NAIgG was high in 36 of 91 patients. Elution studies were performed to determine whether NAIgG has a nature of autoantibodies. In model experiments, the ether elu-ate from neutrophils sensitized with neutrophil-specific alloantibody (anti-NA2) reacted with donor neutrophils, whereas the eluates from those with model immune complexes (ICs) failed. These data indicated that the ether elution technique is useful to determine whether NAIgG consists of anti-neutrophil autoantibodies. The NAIgG on patient's neutrophils was eluted with ether and the reactivity of the eluate with normal neutrophils was investigated. The eluates from 34 of 36 patients with various autoimmune disorders with elevated NAIgG level failed to react with donor neutrophils. These data indicated that the elevated NAIgG in the majority of these patients did not consist of anti-neutrophil autoantibodies, but possibly of ICs.

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The thickness dependences of the ESR, hydrogen vibrational spectra, and optical absorption have been investigated for glow-discharge amorphous Si: H films doped at various doping ratios with phosphorus and boron. The incorporated hydrogen concentration, the spin density at g = 2.0055 associated with dangling bonds, and the optical gap were observed to increase with decreasing film thickness. The thickness dependence of the spin density could not be observed for a film annealed in a hydrogen plasma. Signals with g = 2·0043 and 2·011, respectively, observed for heavily P- and B-doped films, showed little dependence on film thickness, and were not affected by post-hydrogenation. It is suggested that in neither energy band are the localized tail states affected by post-hydrogenation, but the density of localized states arising from dangling bonds, near the middle of the band gap, decreases during post-hydrogenation. These results are analysed in terms of a two layer-model. It is concluded that the increase in spin density arising from dangling bonds and the increase in hydrogen concentration with decreasing film thickness have their origin in an enhanced spin density and hydrogen concentration near the free surface. The relationship between these properties and electrical conductivity is discussed.

Electron spin resonance (ESR), conductivity, X-ray diffraction, optical absorption and hydrogen vibrational spectra have been investigated as functions of the substrate temperature, the r.f. power and the hydrogen dilution ratio for undoped microcrystalline Si films. In microcrystalline films deposited at a higher temperature and at a lower r.f. power, a strong preferential orientation has been found. The standard deviation of the orientation from the normal direction on the surface was less than 2·5° at the minimum. A close relation between the observed properties and the degree of preferential orientation has been found. In a microcrystalline film with a preferential orientation, the g value of ESR arising from dangling bonds in the amorphous phase regions was different from that in a film with a random orientation. The coefficient B estimated from the optical absorption for the former films was larger than that for the latter, and a more enhanced conductivity with post-hydrogenation was observed for the former as compared with the latter. Some examinations of the morphology of the amorphous phase in the microcrystalline Si are made.