Expression of platelet alpha-granule proteins in a human megakaryocytic leukemia cell line (CMK 11-5)

We investigated the expression of three platelet alpha-granule proteins, thrombospondin (TSP), von Willebrand factor (vWF), and fibrinogen (Fbg), in a human megakaryocytic cell line (CMK 11-5) by immunocytochemical staining, using the alkaline phosphatase anti-alkaline phosphatase (APAAP) complex method and immunoelectron microscopy of ultrathin-frozen sections. CMK 11-5, established from a Down's syndrome patient with acute megakaryoblastic leukemia, has characteristics closely resembling those of normal megakaryocytes. Under basal conditions, TSP expression was observed in the alpha-granules, whereas the other two proteins were not detected. When the cells were cultured with 12-o-tetradecanoylphorbol-13-acetate (TPA), the expression of TSP was enhanced and vWF was also detected, but not Fbg. Cells cultured in the presence of plasma for 24 h took up Fbg and stored it in their alpha-granules. These findings suggest that TSP and vWF are synthesized by CMK 11-5 cells, with the former being produced more rapidly than the latter, whereas Fbg is endocytosed from the plasma.

[Measurement of platelet thromboxane A2/prostaglandin H2 receptor in asthmatic patients]

To evaluate the characteristics of platelet TXA2/PGH2 receptors in patients with bronchial asthma, we performed radiobinding assay of gel-filtrated washed platelets obtained from 15 asthmatic patients and 8 normal adults using [3H]-labeled S-145, a TXA2/PGH2 receptor antagonist, as a radiolinged. Data were evaluated by Schatchard's analysis, and the dissociation constant (Kd), an index of the binding characteristic of receptors, and the maximum number of binding sites (Bmax) were calculated. Venous blood was simultaneously collected and was centrifuged, and platelet-rich plasma was prepared. The platelet aggregation rates induced by various concentrations of U-46619, a TXA2 analogue, were measured by Born's method (nephelometry), and the concentration that induced 50% of the maximum platelet aggregation (EC50) was calculated using a concentration-response curve. The Kd value did not differ between the asthmatic patients and normal controls. Some of the asthmatic patients showed a low EC50 and a high Bmax. EC50 was inversely correlated with Bmax. The number of platelet TXA2/PGH2 receptors was shown to be increased in some asthmatic patients.

Treatment of adult T-cell leukemia/lymphoma with MST-16, a new oral antitumor drug and a derivative of bis(2,6-dioxopiperazine). The MST-16 Study Group

BACKGROUND

MST-16, a new orally administered bis(2,6-dioxopiperazine) analogue and an inhibitor of topoisomerase II, was given to 24 patients with adult T-cell leukemia-lymphoma (ATLL) in a Phase I-II multi-institutional cooperative study.

METHODS

MST-16 was administered orally daily for 7 days, with courses repeated at intervals of 2-3 weeks in 24 patients.

RESULTS

Two complete remissions (CR) and eight partial remissions (PR) were obtained in 23 evaluable patients who received 1200-2800 mg/day of MST-16. Among 13 acute-type ATLL, one CR and five PR were obtained. Among eight lymphoma-type ATLL, two PR were detected. Among two chronic-type ATLL, one CR and one PR occurred. Remissions were obtained at 7-232 days (median, 23 days) and lasted 43-374 days (median, 68 days). The major toxic effects were leukopenia (68%), anemia (52%), thrombocytopenia (35%), and gastrointestinal disorders (22%).

CONCLUSIONS

MST-16 was shown to be effective in ATLL, which has no standard therapy. This drug deserves further clinical trials because it shows little cross resistance to currently available antitumor drugs.

Addition of serum from patients with collagen diseases increases to cultured human endothelial cells production and release of von Willebrand factor

The addition of sera from patients with collagen diseases, particularly those with vascular complications, to the supernatant of cultured vascular endothelial cells (EC) in vitro significantly increased the surface and intracellular amounts of von Willebrand factor antigen (vWF:Ag) compared with results obtained with sera from normal healthy subjects. Peak levels of vWF:Ag occurred after 24 h of in vitro culture. Moreover, the amounts of vWF:Ag secreted into the EC supernatant with patient serum added were significantly higher than the amounts secreted into EC supernatant with control serum added, even after 48 h of in vitro culture. Levels of large and intermediate multimers (LIM) of von Willebrand factor (vWF) increased in EC supernatant exposed to serum from patients with collagen diseases as compared with levels in supernatant exposed to serum from normal controls, whereas no significant differences were detected overall between adding the plasma of patients and of normal subjects. In addition, C-reactive protein (CRP) induced a time- and dose-related release of vWF:Ag from EC, while glucocorticoid did not effect the release of vWF:Ag from EC. These results suggest that the sera of patients with collagen diseases, particularly those with vascular complications, stimulate the production and release of LIM of vWF from EC.

Detection of platelet antigen for antiplatelet antibodies in idiopathic thrombocytopenic purpura by flow cytometry, antigen-capture ELISA, and immunoblotting: a comparative study

We compared three methods of detecting platelet antigens for antiplatelet antibodies in patients with idiopathic thrombocytopenic purpura (ITP), i.e., a microtiter well antigen-capture enzyme-linked immunosorbent assay (AC-ELISA), a platelet suspension immunofluorescence test using flow cytometry (PSIFT-FCM), and Western blotting. Using PSIFT-FCM, the reactivity of NNKY1-32, an anti-glycoprotein (GP) IIb/IIIa antibody, and of NNKY5-5 (anti-GPIb) to platelets from 60 ITP patients were examined. By PSIFT-FCM, both the peak channel and the relative fluorescence value were below the mean-2SD for healthy control platelets in 15 patients when NNKY1-32 was used and in 2 patients when NNKY5-5 was used. Western blotting gave an apparent molecular weight for GPIb of 160,000, while GPIIb was 135,000 and GPIIIa was 88,000. By the AC-ELISA, 12 patients were positive for NNKY1-32 and 4 for NNKY5-5. Although NNKY1-32 binding was detected by PSIFT-FCM in 15 of the ITP patients using platelets, only 3 were positive using plasma. By AC-ELISA and Western blotting of plasma, 12 and 10 of the patients were positive for NNKY1-32 and NNKY5-5, respectively. Our results suggest that none of the three methods is good enough to stand alone and that they should be used together in the analysis of platelet antigens for antiplatelet antibodies in ITP.

Ultrastructural analysis of a human megakaryocytic leukemia cell line (CMK11-5) in response to platelet agonists

To further characterize the ultrastructure of the human megakaryocytic leukemia cell line, CMK, and its subclone CMK11-5, was observed. Stimulation with platelet agonists, ADP, thrombin, and collagen caused enlargement of vacuoles, projections of the cell surface, appearance of fibrous material in the enlarged vacuoles, and loss of alpha granules. We also found that horseradish peroxidase (HRP) incorporated into the granular structures of the cell could be transported out of the cell. The activation of CMK cells by platelet agonists indicates that human megakaryocytes may be activated in thrombotic states. CMK with particular megakaryocytic properties is a useful cell model for studying megakaryocytic function.

Early detection of diabetic nephropathy and criteria for the initiation of therapy

In 86 patients with non-insulin-dependent diabetes mellitus who were negative for proteinuria by a test paper method, the albumin excretion rate was compared to the albumin/creatinine ratio, and a baseline albumin/creatinine ratio value was determined at which therapy to arrest the progression of nephropathy should be initiated. The albumin excretion rate, albumin/creatinine ratio, and urinary creatinine excretion were determined from urine samples obtained at outpatient visits. The reproducibility of time-restricted urine sampling was investigated using the creatinine excretion rate. The mean coefficient of variation was found to be 42%, and inaccurate urine sampling appeared to cause variation in the albumin excretion rate. A significant difference was evident between males and females in creatinine excretion (0.823 +/- 0.152 mg/min for males and 0.577 +/- 0.182 mg/min for females, p < 0.001). The baseline albumin/creatinine ratio value for initiating therapy was established to be 36 mg/g creatinine for males and 51 mg/g creatinine for females. Use of the albumin/creatinine ratio appears to provide a simple and valuable index for determining when to initiate therapy for diabetic nephropathy.

Periodic production of antiplatelet autoantibody directed against GPIIIa in cyclic thrombocytopenia

We report here a female patient with cyclic thrombocytopenia associated with antiplatelet autoantibodies. There was an inverse relationship between the level of platelet-associated IgG and platelet count. Bone marrow megakaryocytes were normal in number even during the thrombocytopenia. The binding of monoclonal antibodies (mAbs) against glycoprotein (GP) IIb/IIIa to patient platelets was significantly inhibited in the thrombocytopenic phase, while these mAbs normally bound to patient platelets obtained during the normal platelet count. Western blotting and mAb-specific immobilization of platelet antigens showed that both plasma autoantibody and the eluted IgG from the patient platelets bound to GPIIIa. These results suggest that the periodic production of antiplatelet autoantibody against GPIIIa caused cyclic destruction of platelets in this patient.

Effects of kami-kihi-to (jia-wei-gui-pi-tang) on autoantibodies in patients with chronic immune thrombocytopenic purpura

We studied the effect of Kami-kihi-to (Jia-Wei-Gui-Pi-Tang) on the production of autoantibodies in ten patients with chronic immune thrombocytopenic purpura. After administration of Kami-kihi-to, platelet count was increased in seven of the ten patients (p < 0.05). Using Western blotting, we demonstrated the disappearance of autoantibody reaction with antigen in one patient. However, platelet-associated IgG was decreased in eight of ten patients (p < 0.05). Kami-kihi-to appears to promote the suppression of autoantibodies in patients with chronic immune thrombocytopenic purpura. No side effects were observed in any patient. Thus, Kami-kihi-to may be a useful and safe drug in the management of chronic immune thrombocytopenia purpura.

[Study on the inhibitory effect of AA-2414 on platelet aggregation and its clinical effect in asthmatic patients]

We previously reported that AA-2414, an eicosanoid receptor antagonist, inhibits platelet aggregation mediated by TXA2/PGH2 receptors in patients with bronchial asthma, but that the inhibitory effects differ among individuals. In this study, we measured the in vitro inhibition rate of platelet aggregation by AA-2414 using U-46619 as an aggregating agent in 22 asthmatic patients and classified them into Group A (showing an inhibition rate of 60% or more) and Group B (showing a rate of less than 60%). Subsequently, AA-2414 tablets (40 mg/day) were orally administered to both groups for 6 weeks, and the clinical effects were compared. A positive correlation was observed between the in vitro U-46619-induced platelet aggregation rate and the inhibition rate of aggregation by AA-2414. At the end of administration, marked inhibition of U-46619-induced platelet aggregation was observed in all patients. However, Group A showed a higher improvement rate of symptoms than Group B. Asthmatic patients can be classified into the groups showing good or poor platelet responses. The response may reflect reactivity to TXA2 in the local airway.

[A diabetic patient with empty sella syndrome accompanied by stimulated guanidinoacetic acid metabolism]

Since urinary guanidinoacetic acid (GAA) derives from the kidneys, its detection is suggested to be associated with renal disease. We have been making a practice of investigating renal GAA production in diabetic patients, using a citrulline/creatine loading test. We noted a marked increase in urinary GAA excretion in 1 patient. Since GAA-synthesis is hormonally regulated, we made a through investigation of endocrine function in this patient. She was a 58-year-old woman with a 15-year history of diabetes mellitus, proliferative diabetic retinopathy, and negative microalbuminuria. There was a high plasma GH level and urinary 17-KS analysis revealed an increase in the adrenal androgen-derived fractions. Based on the X-ray finding of ballooning of the sella turcica and the MRI data, empty sella syndrome was diagnosed. It was suggested that stimulated anabolic hormone release had accelerated renal nitrogen metabolism and induced aggravation of her retinopathy. The findings in this patient implied the involvement of hormones in the development of diabetic complications.

[Therapeutic effects of cefuzonam against severe infections in patients with hematopoietic disorders. Hanshin Infection Study Group]

Cefuzonam (CZON) was used to treat severe infections in 151 patients with hematopoietic disorders, and its efficacy and safety were assessed. The drug was given in doses of 2.0 to 6.0 g a day, divided into 2 or 3, intravenously by injection or infusion. The clinical effects were excellent in 34 cases, good in 40 cases, fair in 5 cases, and poor in 57 cases. Therefore, the results were excellent or good in 54.4% of the patients treated. The efficacy rates were 43.8 and 35.9% for groups of patients whose neutrophil counts were 500/microliters or less and 100/microliters or less, respectively. It was excellent or good in 70.6% of patients in whom causative agents were identified, and in 66.7 and 80.0% of patients infected with Gram-negative and -positive bacilli, respectively. The efficacy rate for patients infected with unidentified agents was 52.1%. The rate for patients who had received other antibiotics previously was 41.5%. The rate for patients having received only one antibiotic for the preceding treatment was 50.0%. Six (3.9%) of the treated patients experienced adverse effects including changes in laboratory test results observed in 4.

[Analysis of adhesive proteins on the surface of platelets from the patients with lung cancer: studies in histological type and clinical stage]

Flow cytometry was used to detect platelet-associated fibrinogen (PA-Fbg), platelet-associated fibronectin (PA-FN) and platelet-associated thrombospondin (PA-TSP) on the surface membrane of platelets and plasma (P)-TSP in 30 patients with lung cancer (16 case of adenocarcinoma and 14 of squamous cell carcinoma). ELISA was used to analyze beta-TG and PF4. In the lung cancer group, beta-TG and PF4 were higher than those of a normal control group. PA-Fbg values were correlated with beta-TG and PF4 values. Each adhesive protein had a higher value in the patient than in the normal control group, and the degree of the increase was related to the progression of clinical disease stage. In the squamous cell carcinoma group, the P-TSP value was significantly elevated. Platelet size increased as the clinical stage of the disease progressed. These results suggest the following: 1. An increase in PA-Fbg can indicate the presence of activated platelets. 2. In patients with lung cancer, activated platelets appear in the blood, and their numbers increase as the clinical stage of the disease progresses. 3. Differences in histologic type led to differences in binding adhesive protein.

[Steroid and gamma globulin therapy against virus-associated hemophagocytic syndrome]

A 21-year-old woman was admitted to our hospital because of high fever, cough, and headache. Other clinical manifestations included hepatosplenomegaly, anemia, leukopenia, and mild liver dysfunction. As she had been diagnosed to have systemic lupus erythematosus (SLE) previously, we first suspected that this disease had become exacerbated. However, the titers of anti-EB virus (VCA-IgG) and some other viruses were high on admission, and hemophagocytosis by macrophages was observed on bone marrow examination. Therefore, she was diagnosed to have virus-associated hemophagocytic syndrome (VAHS). Prednisolone therapy was then initiated, but the patient responded poorly. We next tried gamma globulin, and the clinical findings and laboratory data were improved. Our patient showed a very favourable clinical course following gamma globulin therapy, suggesting that steroid and gamma globulin should be considered as a treatment even in the early stages of this syndrome in adults.

Ultrastructural analysis of platelet-like particles from a human megakaryocytic leukemia cell line (CMK 11-5)

Ultrastructural observations were performed to further characterize the human megakaryocytic leukemia cell line, CMK, and its subclone, CMK11-5. We found that particles derived from CMK11-5 cells had cytoplasmic projections and no nucleus, and that some particles contained alpha granules. Incubation with ADP induced fibrinogen receptors on the surface of these particles. Furthermore, the particles had glycoprotein Ib antigen on their surfaces, and attached nonreversibly to rabbit aortic subendothelium, showing associated morphological changes similar to those observed in normal platelets. CMK and CMK11-5 are the first megakaryocytic cell lines that have been found to release particles that have some of the same functions as normal platelets. In particular, CMK11-5 seems to be a useful model for studying megakaryocyte function.

[Evaluation of platelet aggregation test by grading curve]

In order to standardize the platelet aggregation test, we used the grading curve (GC) produced by plotting four concentrations (0.5, 1.0, 2.0 and 4.0 microM) of ADP and four concentrations (0.25, 0.5, 1.0 and 2.0 micrograms/ml) of collagen, which are aggregation inducers, along the horizontal axis and plotting their individual rates (%) of aggregation 5 minutes after administration, along the longitudinal axis. The degree of platelet aggregation was classified in 6 stages (Types III, II, I, 0, -I and -II), ranging from marked increase to marked decrease, according to the GC of ADP aggregation in healthy subjects. Type I or 0 ADP aggregation was observed in 78% of the subjects, and Type I collagen aggregation was observed in about 50% of the subjects, whereas patients with cerebral infarction showed distinct increases in Type III and II aggregations of both ADP and collagen. In most patients who were treated with antiplatelet drugs, the aggregation were Type 0, -I or -II. The concentration of inducer, which corresponded to the maximum 50% value of the GC (Max 50) was significantly correlated with the minimum concentration (threshold concentration) in ADP aggregation, at which secondary aggregation was induced even if it was reversible, and with the minimum concentration (threshold concentration) in collagen aggregation, at which the aggregation rate 5 minutes after administration increased to 50% or higher. The GC of platelet aggregation seemed to enable easy determination of the degree of aggregation, and was also considered to be useful for monitoring platelet aggregation during the administration of antiplatelet drugs.

Clinical test of renal guanidinoacetic acid metabolism by oral citrulline and creatine loading

We devised a clinical test of renal metabolism based on the synthesis of guanidinoacetic acid from citrulline in the proximal convoluted tubule. Intravenous administration of a citrulline/creatine solution to rats with modified levels of renal glycine amidinotransferase activity revealed a strong correlation (r = 0.921) between this activity and urinary guanidinoacetic acid excretion. Citrulline (1.75 g) and creatine (1.50 g) were administered orally to healthy individuals and patients with chronic glomerulonephritis. In the healthy individuals, urinary guanidinoacetic acid excretion increased 5-fold by 2 h after dosing (15.1 +/- 2.2 vs. 2.8 +/- 1.1 mg/h). In the glomerulonephritis patients, blood clearance of citrulline decreased as the creatinine clearance decreased and urinary guanidinoacetic acid excretion also decreased. Of 56 patients with glomerulonephritis or diabetes mellitus, one had increased urinary guanidinoacetic acid excretion associated with an excess of adrenal androgens. This test appears a useful, noninvasive and simple method for examining the metabolic activity of the renal proximal convoluted tubules.

Anti-phospholipid antibodies bind to platelet microparticles in idiopathic (autoimmune) thrombocytopenic purpura

We recently reported that IgM antibody-related microparticles exist in some patients with idiopathic thrombocytopenic purpura (ITP) [14]. In this study, we investigated the relationship between antiphospholipid (cardiolipin and phosphatidylinositol) antibodies and microparticles in 56 ITP patients. We used an ELISA to detect anti-phospholipid antibodies. IgG antibodies against cardiolipin and phosphatidylinositol were detected in 13 and 12 patients, respectively. The titers of IgG antibodies against these phospholipids did not correlate with the platelet-associated IgG level or the platelet count. Next, we investigated the binding of anti-phospholipid antibodies to platelets and microparticles. Microparticles were obtained by incubating washed platelets with collagen plus thrombin. ITP plasma containing IgG-class anti-phospholipid antibodies showed significantly increase binding to microparticles compared with plasma without such antibodies (p less than 0.001). Our results suggest that anti-phospholipid antibodies could affect the function of platelet microparticles in ITP.

Purification of factor XIa inhibitor from human platelets

An inhibitor of activated factor XI (FXIa) in human platelets was recently identified as an amyloid beta-protein precursor (APP). We purified an FXIa inhibitor (XIaI) from the supernatant of activated human platelets, and assessed its inhibitor activity toward FXIa amidolytic activity. Approximately 90 micrograms of XIaI that cross-reacted with anti-APP antibody was obtained from two hundred units of platelet suspension by employing a six-step column chromatography procedure. The molecular weight of the purified XIaI was 94,000. The Ki value of XIaI to factor XIa was 526 +/- 120 pM, and the inhibition was enhanced by the addition of ZnCl2. The amino-terminal sequence of XIaI was L-E-V-P-T-D-G-N-A-, which is identical to that for the leucine (N18) to alanine (N26) sequence of APP751 and the amino-terminal sequence of protease nexin-2.

Effects of injected antibody against the platelet glycoprotein IIb/IIIa complex on monkey platelet fibrinogen

Four monkeys were injected for a 10-day period with the Fab fragment of a murine monoclonal antibody (NNKY 1-32) which inhibits the binding of fibrinogen to the platelet glycoprotein (GP) IIb/IIIa complex. Platelet fibrinogen levels were assessed quantitatively by electroimmunoassay and qualitatively by immunoelectron microscopy. The platelet fibrinogen level fell to 9.0 +/- 2.8% of the control level after antibody administration. Immunoelectron microscopy showed that the injected antibody was localized on the inner surface of the platelet alpha-granule membrane. Our findings suggest that the GP IIb/IIIa complex can be internalized by alpha-granules and that it may mediate the endocytosis of plasma fibrinogen by platelets.

[Late phase II study of MST-16 (sobuzoxane) efficacy for malignant lymphoma]

A late phase II study with MST-16 for malignant lymphoma was performed with the collaboration of 11 institutions belonging to the Hanshin Hematological Disease Treatment Research Group. Out of a total 40 patients entered into the study, 37 cases (33 of NHL and 4 HD) were evaluated for efficacy and 27 cases for side effects. The response rate was 29.7% (2 cases of CR and 9 PR). The factors affecting response rate were histological classification, phenotype of tumor cell surface and stage of disease. Bone marrow suppression and G-I disorders were the main toxicities observed, but they disappeared by the cessation of MST-16 treatment.

[Analysis of the GPIIb and GPIIIa genes in patients with Glanzmann's thrombasthenia]

Glanzmann's thrombasthenia (GT) is an autosomal recessive bleeding disorder due to a deficiency or abnormality of glycoproteins (GPs) IIb and IIIa, but its genetic basis remains to be determined. We analyzed the genes for GPIIb and 3'GPIIIa in 3 patients with GT and in 7 control subjects by Southern blot. No large deletions or insertions were detected in these genes in any patient with GT. Furthermore, the GPIIb and GPIIIa mRNAs derived from the platelets of patients with GT could be amplified using the reverse transcriptase-polymerase chain reaction (RT-PCR). This finding indicates that the mRNAs of the patients with GT are considered to be normally transcribed. The molecular defects of the GPIIb.

[Clinical and preclinical pharmacology of KC-764, a novel antiplatelet agent]

Preclinical pharmacological studies showed that KC-764 was more potent and more selective in inhibiting platelet aggregation than aspirin. The concentration of KC-764 for inhibiting PGI2 production in the aorta was 70 times higher than that for inhibiting TXA2 in platelets. Antiplatelet action of KC-764 was augmented by plasma components. This augmentation by plasma may lead to selective antiplatelet activity. KC-764 has been investigated for platelet function in patients with chronic cerebral infarction. KC-764 at 10, 20 and 40 mg b i d, inhibited platelet aggregation induced by arachidonic acid, collagen, and ADP, and its potency was almost equal to aspirin at 100-330 mg daily. Plasma TXB2 levels were markedly depressed by KC-764 but plasma 6-keto-PGF1 alpha levels were not influenced. On the contrary, aspirin depressed both plasma prostanoids. These findings suggest that KC-764 can overcome the 'aspirin dilemma'.

[Report of two cases of neonatal alloimmune thrombocytopenia caused by anti-HLA antibody, and their screening using umbilical cord blood]

Here reported are two cases with neonatal alloimmune thrombocytopenia (NAITP). In our 2 cases, anti-HLA antibodies, i.e. anti-HLA-A24+B51 and anti-HLA-Bw61+Cw3, respectively, were detected in the mother's sera, which reacted to each patient's lymphocytes and were presumed to have been contribute to NAITP. The thrombocytopenia, found on routine laboratory examination, recovered within 1 to 3 weeks without any therapy in both cases. Further, the relationship of platelet count and PAIgG in neonatal babies (umbilical cord blood) to anti-HLA antibodies in their mothers were examined in 284 pairs. Thrombocytopenia less than 150,000/microliters was found in 16/284 babies (5.6%), 3 of the 16 (1.1% of the total) being positive for anti-HLA, and one positive for PAIgG. Four (1.4%) of the 284 babies were positive for PAIgG, one of whom was thrombocytopenic, and one positive for anti-HLA. Anti-HLA antibody was found in 25/284 mothers (8.8%). Nevertheless, none of the pairs showed positive reactions in all of three tests. It seems that passive transfer of maternal anti-HLA antibodies to the fetus is not itself sufficient to cause thrombocytopenia. On the other hand, some NAITP cases may have been overlooked because of their mildness.

Anti-glycoprotein IIb/IIIa autoantibodies are reversibly internalized into platelets in idiopathic (autoimmune) thrombocytopenic purpura

We used flow cytometry to investigate the binding of platelet-binding IgG (PBIgG) to unfixed platelets in idiopathic thrombocytopenic purpura (ITP), including that of anti-glycoprotein (GP) IIb/IIIa antibodies. Anti-GPIIb/IIIa antibodies were detected in 13/64 ITP patients using antigen-capture ELISA and immunoblotting. When unfixed platelets were incubated with ITP plasma, the PBIgG level was significantly higher than after incubation with normal plasma. When 1 microM ADP was added to unfixed platelets, which were incubated with ITP plasma and washed, the PBIgG level increased additively. GMP-140 is a constituent of platelet alpha-granules, and a monoclonal antibody directed against this protein showed weak binding to platelets after 1 microM ADP stimulation. The increase of PBIgG produced by ADP was significantly greater when ITP plasma positive for anti-GPIIb/IIIa antibody was used compared with that obtained using antibody-negative ITP plasma. This increase of PBIgG was markedly inhibited by the removal of extracellular calcium with EDTA or the dissociation of the GPIIb/IIIa complex by EDTA treatment at 37 degrees C. These results suggest that anti-GPIIb/IIIa autoantibodies are internalized by unfixed ITP platelets and stored somewhere other than the alpha-granules. This stored antibody pool can be reversibly redistributed on the platelet surface by weak stimulants such as ADP and a functional GPIIb/IIIa complex appears to be necessary for this to occur.

[A study of combination chemotherapy (BHAC-ACVP) for adult acute lymphocytic leukemia. Hanshin Co-operative Study Group of Hematological Malignancies]

Twenty-nine adult patients with acute lymphocytic leukemia (ALL) were treated with combination chemotherapy consisting of behenoyl-ara-C, adriamycin, cyclophosphamide, vindesine and prednisolone (BHAC-ACVP regimen). Complete remission (CR) was obtained in 7 of 13 (54%) of the previously untreated, and 4 of 16 (25%) of the previously treated patients. Six of 10 (60%) L1 and 5 of 17 (29%) L2 patients achieved CR. Side effects such as nausea, GPT elevation and fever were observed, but these were not severe in most cases. The result indicates that BH-AC is useful for the treatment of adult patients with ALL.

Differences between platelet and microparticle glycoprotein IIb/IIIa

Glycoprotein (GP) IIb and IIIa are major constituents of the platelet membrane which are involved in forming the fibrinogen receptor on activated platelets. We used flow cytometry to study the effects of ethylene-diamine tetraacetic acid (EDTA) on the membrane GPIIb/IIIa complexes of platelets and microparticles, and to study the effects of cations on dissociated GP complexes. Microparticles were detected by both the volume signal and by fluorescence using an FITC-conjugated anti-GPIb antibody (NNKY5-5). When platelets were stimulated with ADP, calcium ionophore A23187, or thrombin, fibrinogen binding to the platelet surface increased markedly. However, fibrinogen binding to microparticles showed little increase in response to such agonists. Microparticle GPIIb/IIIa complexes were dissociated by incubation with EDTA at 37 degrees C but did not reassociate after treatment with divalent cations (Ca2+, Mg2+, and Mn2+) in contrast to platelet GPIIb/IIIa complexes. These results suggest that some interaction of GPIIb/IIIa and linked structures like the platelet cytoskeleton may be involved in the reassociation of dissociated GPIIb and GPIIIa, perhaps explaining the failure of reassociation of microparticle GPIIb/IIIa (i.e., the fibrinogen binding to microparticles).

Presence of platelet-activating factor in pyuria in humans

The relationship between the occurrence of platelet-activating factor (PAF) and neutrophils in urine from patients with urinary tract infection was examined. PAF was detected in human pyuria, when leukocyte levels reached at least 300 cells/microL (n = 45), but not in normal urine (n = 12). The amount of PAF found in pyuria, measured by platelet aggregation assay, was 0.01 to 13.3 pmol/mL. A close correlation was seen between the amount of PAF present and the number of urinary leukocytes (p less than 0.01, r = 0.70). The leukocytes in pyuria consisted almost entirely of neutrophils (96 +/- 4%, mean +/- S.D.). Our findings suggest that the occurrence of PAF is associated with the accumulation of neutrophils in urine.

[Primary myelofibrosis transforming into multiple subcutaneous monoblastoma--a case report]

A 83-year-old man was diagnosed with primary myelofibrosis based on the presence of leukoerythroblastosis, splenomegaly, chromosome 46 XY, a dry tap bone marrow aspiration and fibrosis on bone marrow biopsy, when he was admitted for herpes zoster in June 1987. He was admitted for a second time with multiple subcutaneous tumors over his entire body in July, 1989. He had mild splenomegaly, but no hepatomegaly nor lymphadenopathy. Laboratory tests were as follows: RBC 214 x 10(4)/microliters, Hb 5.1 g/dl, Ht 17.7%, WBC 3,200/microliters with leukoerythroblastosis, platelets 11.6 x 10(4)/microliters, s-lysozyme 251 micrograms/ml, u-lysozyme 770 micrograms/ml, NAP ratio 98%, score 278. Bone marrow aspiration resulted in a dry tap. Bone marrow biopsy showed marked fibrosis. Histologic examination of subcutaneous tumor biopsy specimens revealed a diffuse infiltration of monocytes with flexuous nuclei. These cells were positive for alpha-naphtyl butyrate esterase stain, and negative for peroxidase, alpha-naphtol ASD chloroacetate esterase stain and platelet glycoprotein IIb/IIIa stain (APAAP). Ultrastructurally, these cells were mostly monocytes and promonocytes, while phenotypically, CD11b, CD13, CD14, CD33 and HLA-DR were positive. These date indicated that the subcutaneous tumors originated from monocytes.

Plasma coagulation and fibrinolysis parameters in patients with collagen diseases, and analysis of the multimeric structure of von Willebrand factor (vWF)

We studied the relationship between vascular complications and coagulation and fibrinolysis parameters in 75 subjects with collagen diseases. Thirty normal healthy persons served as controls. We found that patients with collagen diseases were in a state of a hypercoagulation and hyperfibrinolysis. In SLE (systemic lupus erythematosus) in particular, coagulation and fibrinolysis parameters appeared to be indices of vascular complications. Increases in the levels of thrombin-antithrombin III complex (TAT) and alpha 2-plasmin inhibitor-plasmin (PIP) were particularly associated with proteinuria, while increases in fibrinopeptide A (FPA) levels were associated with Raynaud's phenomenon. Administration of glucocorticoid seemed to improve the hypercoagulation and hyperfibrinolytic states of patients with collagen diseases. Analysis of the multimeric structure of von Willebrand factor (vWF) revealed a tendency for large and intermediate multimers (LIM) of plasma vWF to increase in SLE patients with accompanying vascular complications, whereas such increases were not observed in SLE patients without any vascular complications. Therefore, analysis of the multimeric structure of vWF appeared to be a useful indicator of vascular complications in collagen diseases.

[Detection of human immunodeficiency virus type-1 (HIV-1) DNA by polymerase chain reaction using nonradioactive probe and virus isolation]

We compared the results obtained with the polymerase chain reaction (PCR) and virus isolation from peripheral blood mononuclear cells (PBMC) in HIV seropositive and seronegative persons. Three primer pairs of SK38/39 (gag). SK29/30 (LTR) and SK68/69 (env) were used in the amplification of the HIV DNA sequences, and KM29/38 (beta-globin) was used as the inner control. The PCR-positive rate among the virus-isolation-positive persons was SK38/39:100% (22/22), SK29/30:95.5% (21/22) and SK68/69:90.0% (20/22). The PCR-positive rate among the virus-isolation-negative persons was SK38/39:60% (6/10), SK29/30:60% (6/10) and SK68/69:80% (8/10), and two subjects were PCR-negative with all primer pairs. We could not detect HIV DNA from seronegative samples, and all subjects were positive with the inner control. Each primer pair expressed a different PCR-positive rate. There are possible explanations for the low PCR-negative rate on virus-isolation negative-subjects that the number of infected cell was rare or infected HIV contained genetic variations or deletions. We considered that the results of PCR correlated with the character of HIV as infectivity.

Inhibition of platelet aggregation by low concentrations of sodium fluoride. Significance of the intracellular calcium ion concentration

Sodium fluoride activates platelets but its mechanism of action has not yet been completely identified. We examined the effect of a low concentration of sodium fluoride (which could not cause aggregation) on thrombin-induced changes in the intracellular calcium ion concentration ([Ca2+]i). In the presence of 1 mM extracellular Ca2+, preincubation with a low concentration of sodium fluoride decreased the peak of the thrombin-induced elevation of [Ca2+]i, when measured with aequorin. When [Ca2+] was measured using fura-2, preincubation caused no marked changes in its peak, but the later changes that were thought to mainly reflect extracellular Ca2+ influx were inhibited. The inhibitory mechanism of sodium fluoride appears to depend on reducing extracellular Ca2+ influx. Aequorin appears to reflect [Ca2+]i near the cell membrane and is thus easily affected by the extracellular Ca2+ influx.

Platelet free Ca2+ concentration in non-insulin-dependent diabetes mellitus

We made serial measurements of the platelet intracellular free calcium concentration in 167 patients with non-insulin-dependent diabetes mellitus (77 males and 90 females) over a two-year period, and investigated the relationship between this parameter and diabetic angiopathy. We measured both the basal and thrombin-stimulated platelet free calcium concentrations using fura-2/AM as a fluorescent indicator. The patients were grouped according to the severity of nephropathy, retinopathy, and hypertension and their hemoglobin A1c levels. The basal platelet calcium level of the diabetic patients was higher than that of a healthy control group. There were high levels in the patients with mild nephropathy and retinopathy, but low levels in those with severe disease, and the platelet calcium level reflected the degree of progression of diabetic angiopathy. Stimulated platelet calcium varied with the progression of nephropathy, being highest in early nephropathy and lowest after proteinuria developed. Our findings suggested that abnormalities of calcium handling may be related to the onset of diabetic vascular complications, especially diabetic nephropathy.

[Effects of maintenance treatment after high-dose intravenous gamma-globulin for idiopathic thrombocytopenic purpura]

High-dose intravenous immunoglobulin (IVIG) for idiopathic thrombocytopenic purpura (ITP) produces a dramatic and substantial increase in platelet count, but the increased count tends to return rapidly to its pretreatment level. We studied the effects of immunosuppressive treatment aimed at the maintenance of platelet counts following the IVIG administration in ITP. Thirty-five patients with ITP were treated with IVIG, and then thirty-two of them with an immunosuppressant (azathioprine) and a glucocorticoid (prednisolone). After IVIG, the platelet count increased significantly. With immunosuppressive therapy after IVIG, most patients had a tendency to maintain the counts. In particular, this maintaining effect was remarkable in those patients who had been responsive to the standard prednisolone therapy while non-responders to the prior prednisolone failed to maintain the counts. When prednisolone was given after IVIG, the effect of maintaining platelet counts was dose-dependent. The treatment with azathioprine and prednisolone after IVIG appears to be effective in maintenance of platelet counts.

Relationship between platelet volume and anti-platelet autoantibodies in idiopathic thrombocytopenic purpura

We used flow cytometry to explore the relationship between platelet volume and anti-platelet autoantibodies in 71 patients with idiopathic thrombocytopenic purpura (ITP). An increase in platelet volume was found more frequently in patients with a platelet count of less than 20,000/microliters. Platelet volume was larger in patients without anti-GPIIb/IIIa autoantibodies than in patients with these autoantibodies. Furthermore, the platelet count was significantly lower in patients without anti-GIIb/IIIa autoantibodies than in the patients with these autoantibodies. There was a positive correlation between a large platelet volume in patients with a platelet count of less than 30,000/microliters and high platelet-associated IgM levels. These results suggest that the platelet volume is related to the severity of thrombocytopenia in ITP.

The ultrastructure and distribution of fibrinogen, von Willebrand factor, and glycoprotein IIb/IIIa complex in platelet alpha-granules by cryo-ultramicrotomy

Transformation upon mild stimulation and the ultrastructure of blood platelet alpha-granules were examined using cryo-ultramicrotomy. An ultrastructural study found not only round, but also elongated and drumstick-shaped alpha-granules and rod-like structures protruding from round alpha-granules. Some elongated alpha-granules showed distinctive cross-striations in the short axis with a periodicity in the order of 19-22 nm. Gold particle-labeled fibrinogen (Fbg) was observed on elongated alpha-granules having cross-striations. Electron-dense nucleoids were observed on some round alpha-granules. An electron-dense nucleoid, intermediate zone, and an electron-lucent matrix were noted in round alpha-granules by gold particle-labeled Fbg in the intermediate zone. Gold particle-labeled von Willebrand factor (vWF) was observed in alpha-granules except in nucleoid zones. Labeling for Fbg was also observed in rod-like structures protruding from round alpha-granules. Gold particle-labeled glycoprotein (GP)IIb/IIIa complex was observed on the inner face of alpha-granule membranes. A few elongated and drumstick-like alpha-granules were found on freshly fixed platelets. Elongated alpha-granules were only found in a small percentage of washed and collagen-stimulated platelets. Cryo-ultramicrotomy is useful for examination of the distribution of intracellular antigens.

Synergistic action in platelet activation induced by an antiplatelet autoantibody in ITP

We detected an autoantibody which activated normal platelets in a patient with immune thrombocytopenic purpura and investigated the mechanism by which this autoantibody mediated platelet activation. The patient's IgG induced platelet aggregation and ATP secretion in normal platelet-rich plasma (PRP). IgG-induced aggregation was inhibited by aspirin (ASA), apyrase, a protein kinase C (PKC) inhibitor and two anti-platelet glycoprotein (GP) IIb/IIIa monoclonal antibodies. The increase of aequorin-detected intraplatelet Ca2+ induced by the patient's IgG was extremely slight. Phosphorylation of a 40 kDa protein was induced by the patient's IgG without any obvious phosphorylation of a 20 kDa protein, and was inhibited by a PKC inhibitor but not by ASA. With ASA-treated normal PRP, the patient's IgG failed to induce aggregation itself, but enhanced ADP- or STA2-induced aggregation. Western blotting and immunoprecipitation experiments showed that the patient's IgG reacted to a protein of 36 kDa. These results suggest that the platelet activation induced by this autoantibody depended on both the selective activation of PKC and the slight Ca2+ mobilization induced by thromboxane A2 synthesis, while the aggregation depended on secretion induced by the synergistic action of the above two mechanisms and was mediated through GP IIb/IIIa.

Antiplatelet autoantibody-related microparticles in patients with idiopathic (autoimmune) thrombocytopenic purpura

We used flow cytometry to detect antiplatelet antibody-related microparticles (MP) in 56 patients with idiopathic thrombocytopenic purpura (ITP). We measured MP in platelets following various types of stimulation in two experimental systems. In one system washed platelets were incubated with normal serum which included the complement system, and in the other, washed platelets were incubated with Tyrode's buffer. There were no differences between the two measurement systems in the degree of increase in MP using various agonists. An increase in MP using ITP plasma was found in 12 out of 56 patients. In particular, four patients showed a significant increase in MP in washed platelets (WP) plus serum. Furthermore, the increase in platelet-associated IgM (PAIgM) was significant in these patients. There was also a definite positive correlation between PAIgM and the percentage of MP of WP plus serum. On the other hand, no specificity for MP formation with anti-GPIIb/IIIa or anti-GPIb autoantibodies was observed. IgM antibody-related MP appear to exist in some patients with ITP.

Influences of antiplatelet autoantibodies on platelet function in immune thrombocytopenic purpura

We investigated the characteristics of the antiplatelet autoantibodies in 60 patients with ITP. Using flow cytometry, the binding of monoclonal antibodies to the platelet glycoprotein (GP) IIb/IIIa complex and to GPIb was examined in these patients. The extent of binding was decreased in 15 patients (anti-GPIIb/IIIa in 12 patients and both anti-GPIIb/IIIa and anti-GPIb in 3 patients). Western blotting revealed that 10 of these 15 patients had either anti-GPIIb or anti-GPIIIa and 2 had anti-GPIb autoantibodies, ADP-induced aggregation of normal platelets was inhibited by autoantibodies in 12 of 60 patients, and 11 of these had anti-GPIIb/IIIa antibodies. Ristocetin-induced aggregation was inhibited in 4 of these patients, and 2 with prominent inhibition had anti-GPIb antibodies. There was a significant relationship between platelet-associated IgG value and ATP secretion. These results suggest that some antiplatelet autoantibodies can affect platelet function and thus have an influence on the pathophysiology of ITP.