The role of TNFalpha and IL-17 in the development of excess IL-1 signaling-induced inflammatory diseases in IL-1 receptor antagonist-deficient mice

IL-1 receptor antagonist (IL-1Ra)-deficient mice spontaneously develop several inflammatory diseases, resembling rheumatoid arthritis, aortitis, and psoriasis in humans. As adoptive T cell transplantation could induce arthritis and aortitis in recipient mice, it was suggested that an autoimmune process is involved in the development of diseases. In contrast, as dermatitis developed in scid/scid-IL-IRa-deficient mice and could not be induced by T cell transfer, a T cell-independent mechanism was suggested. The expression of proinflammatory cytokines was augmented at the inflammatory sites. The development of arthritis and aortitis was significantly suppressed by the deficiency of TNFalpha or IL-17. The development of dermatitis was also inhibited by the deficiency of TNFalpha. These observations suggest that TNFalpha and IL-17 play a crucial role in the development of autoimmunity downstream of IL-1 signaling, and excess IL-1 signaling-induced TNFalpha also induces skin inflammation in a T cell-independent manner.

An optical spectrum of the afterglow of a γ-ray burst at a redshift of z = 6.295

The prompt gamma-ray emission from gamma-ray bursts (GRBs) should be detectable out to distances of z > 10 (ref. 1), and should therefore provide an excellent probe of the evolution of cosmic star formation, reionization of the intergalactic medium, and the metal enrichment history of the Universe. Hitherto, the highest measured redshift for a GRB has been z = 4.50 (ref. 5). Here we report the optical spectrum of the afterglow of GRB 050904 obtained 3.4 days after the burst; the spectrum shows a clear continuum at the long-wavelength end of the spectrum with a sharp cut-off at around 9,000 A due to Lyman alpha absorption at z approximately 6.3 (with a damping wing). A system of absorption lines of heavy elements at z = 6.295 +/- 0.002 was also detected, yielding the precise measurement of the redshift. The Si ii fine-structure lines suggest a dense, metal-enriched environment around the progenitor of the GRB.

Measurement of soluble Fcgamma receptor type IIIa derived from macrophages in plasma: increase in patients with rheumatoid arthritis

FcgammaRIII (CD16) is found in two alternative forms, a transmembrane FcgammaRIIIa expressed on NK cells and macrophages, and a glycosylphosphatidylinositol-linked FcgammaRIIIb present on neutrophils. Previously, we measured soluble FcgammaRIIIa (sFcgammaRIIIa) in plasma of NA(1 +, 2-) phenotyped donors with the anti-FcgammaRIII monoclonal antibody (MoAb) GRM1, which recognizes NA2-FcgammaRIIIb and FcgammaRIIIa. The level of sFcgammaRIIIa, as well as the total sFcgammaRIII (sFcgammaRIIIa plus sFcgammaRIIIb) in patients with rheumatoid arthritis (RA) was significantly higher than that in healthy controls. In this study, we measured sFcgammaRIIIa(M)(phi) in plasma with a newly developed anti-FcgammaRIII MoAb, MKGR14 (mIgM), which recognizes FcgammaRIIIa(M)(phi) specifically. From the recovery of purified sFcgammaRIIIa(M)(phi), the amount of sFcgammaRIIIa(M)(phi) present was about half that of sFcgammaRIIIa(NK), and that of sFcgammaRIIIa was about 50 times lower than that of sFcgammaRIIIb in pooled plasma from healthy NA(1 +, 2-) phenotyped donors. The level of sFcgammaRIIIa(M)(phi) in RA patients was about four times higher than that in healthy controls. In RA patients, both the sFcgammaRIIIa(M)(phi) and sFcgammaRIIIa levels were increased as proportionally as the Lansbury Index. The sFcgammaRIIIa, but not sFcgammaRIIIa(M)(phi) levels, were increased directly proportional to C-reactive protein. sFcgammaRIIIa(M)(phi) may be a novel marker of disease activity in RA.

Lupus anticoagulant in myasthenia gravis associated with IgM gammopathy

The plasma of a patient with myasthenia gravis had strong lupus anticoagulant activity and his IgM paraprotein displayed non-specific inhibition to coagulation factors IX, XI, XII, prekallikrein, and high molecular weight kininogen. He was placed on prednisolone, which resulted in improvement in his myasthenic symptoms, but the prolongation of APTT and macroglobulinemia remained. Double filtration plasmapheresis successfully decreased the serum IgM level from 1,190 mg/dl to 375 mg/dl and APTT improved from 58 s to 38 s. Myasthenia gravis is frequently associated with other autoimmune diseases, but the association with lupus anticoagulant and IgM gammopathy is rare.

All-trans retinoic acid inhibits vascular smooth muscle cell proliferation targeting multiple genes for cyclins and cyclin-dependent kinases

Retinoids have been shown to promote vascular smooth muscle cell differentiation, although the underlying mechanism is unclear. In fact, treatment of rat aortic smooth muscle cells with all-trans retinoic acid (ATRA) has been shown to markedly elevate the mRNA and protein levels of smooth muscle alpha-actin. Considering that an exit from the cell cycle is a prerequisite for cell differentiation, we examined the effect of ATRA on cellular events during the progression from Go to S phase. Pretreatment with ATRA dose-dependently inhibited DNA synthesis induced by basic fibroblast growth factor. However, ATRA did not inhibit transient activation of mitogen-activated protein kinase (MAPK) in response to mitogenic stimulation. And ATRA consistently failed to influence the phosphorylation of MAPK kinase (MEK) and the expression of MAPK-specific dual phosphatase (MKP-1). ATRA did not interfere with other early mitogenic signals either, such as the phosphorylation of FGF-1 receptor or the induction of immediate early genes c-fos, c-jun, and c-myc. In contrast, ATRA strongly suppressed the pRb kinase activities of the cyclin-dependent kinases (Cdks) Cdk4, Cdk6, and Cdk2. ATRA did not influence the expressions of Cip/Kip family Cdk inhibitors or those of cyclins D1 and D2, whereas it strongly inhibited the expressions of cyclins D3 and E, Cdk4, Cdk6, and Cdk2. These results suggest that ATRA targets multiple genes essential for entry into the cell cycle and for the subsequent progression to G1 phase, but without interrupting early mitogenic signals upstream of MAPK.

FcgammaRIII b and FcgammaRIIa polymorphism may affect the production of specific NA1 autoantibody and clinical course of autoimmune neutropenia of infancy

We studied 18 children with autoimmune neutropenia (AIN) to evaluate whether there was a possible relationship between the specificity of granulocyte autoantibodies (anti-NA1,2) and the phenotype of the NA system. Direct granulocyte immunofluorescence test (D-GIFT) was positive in all patients, and indirect granulocyte immunofluorescence test (I-GIFT) was positive in 17 of these 18 patients, respectively. Fourteen of 18 patients showed preferential binding to neutrophils from NA(1+2-) phenotyped donors. Immunoblotting with anti-FcgammaRIIImAb showed that IgG prepared from 7 of 12 patients precipitated both FcgammaRIIIb from NA1 and NA2 neutrophil lysate, whereas the other 5 precipitated only NA1. Patients' IgG did not react with purified FcgammaRIIa. FcgammaRIIIb genotype were NA(1+2-) in 15 of 18 patients and NA(1+2+) in the other 3. FcgammaRIIa type of all patients were (H+R-). These distributions were significantly different from those of healthy Japanese blood donors (n = 608). The genotype of FcgammaRIIIb and FcgammaRIIa may affect the production of neutrophil specific auto-antibodies in AIN of infancy and influence its clinical course.

Identification of endogenous ouabain in culture supernatant of PC12 cells

OBJECTIVE

Ouabain-like factor (OLF), assayed as ouabain-like immunoreactivity (OLI), is thought to represent an endogenous digitalis-like factor. We found increased plasma OLI during the surgical removal of a pheochromocytoma. The elution volume of the OLI extracted from plasma and the pheochromocytoma tissue was the same as that for authentic ouabain, using reverse phase high-performance liquid chromatography. The present study was performed to characterize OLF from the culture supernatant of a rat pheochromocytoma cell line, PC12 cells.

DESIGN

OLI from culture supernatant and chromatographic fractions were assayed by a sensitive enzyme-linked immunosorbent assay for ouabain. PC12 cells, subcultured in RPMI 1640 with 10% horse serum and 5% fetal bovine serum, were washed, and then cultured in Iscove's modified Dulbecco's medium (Life Technologies, Rockville, Maryland, USA) with 0.4% bovine serum albumin (without serum). Progesterone was added to augment the production or secretion of OLI. The conditioned medium was acidified to dissociate the binding protein, and OLI was purified by five steps of octadecylsilane (ODS) column chromatography. The structural identity of this OLI was determined by liquid chromatography and mass spectrometry (LC/MS).

RESULTS

OLI in the culture medium increased after addition of progesterone in a dose-dependent manner. The concentration in the culture medium was approximately double of that in homogenized PC12 cells. After five rounds of ODS column chromatography, approximately 100 ng of OLI was purified from 21 of culture supernatant, without fetal calf serum, in the presence of progesterone. The molecular size of purified OLI was found to be identical to authentic ouabain, based on analysis by LC/ MS.

CONCLUSION

Mammalian cells originating from a rat pheochromocytoma cell line were found to produce and/or secrete OLF by the addition of progesterone.

[A patient with hemorrhage originating from an unknown coagulation pathway inhibitor]

The hemorrhagic disorders associated with circulating anticoagulant are rare but well known as the disease derived from inhibitors(alloantibody or autoantibody), which arise against specific coagulation factors. We encountered a patient with hemorrhage at the lower limbs originating from an unknown coagulation pathway inhibitor. Activated partial thromboplastin time(APTT) prolonged and cross mixing test indicated a coagulation pathway inhibitor. Levels of coagulation factors VIII, IX, XI, and XII were extremely low. Predonine therapy was effective to stop the hemorrhage. To clarify the inhibitor, we treated the patient's plasma with protein A Sepharose, and the factor VIII activity was recovered to a normal level after passing through the column. Gel filtration of the patient's plasma and protein A Sepharose adsorbed fraction of the patient's plasma with Superdex 200 revealed that the inhibitor activity against blood coagulation eluted at the position of IgG, which was detected by the prolongation of APTT of normal pooled plasma. These data indicated that the inhibitor was IgG and its inhibitory spectrum was non-specific and broad. The results of laboratory tests and the clinical features in our patient were similar to those in a previous study by Dahlback(Blood 62, 218-225, 1983). The hemorrhagic abnormality of that patient was derived from the autoantibody to phospholipid, which inhibits the activation of prothrombin. An investigation into the effect of anti-phospholipid antibody in our patient is currently being performed in our laboratory.

Possible role of chronic infection with Chlamydia pneumoniae in Japanese patients with acute myocardial infarction

Chlamydia pneumoniae, a common human respiratory pathogen, has been implicated in the pathogenesis of coronary heart diseases (CHD) in several seroepidemiological studies. The present case-control study investigated the relation between serologic evidence of C. pneumoniae infection and CHD in a Japanese population. Two groups of cases were enrolled: 26 patients with acute myocardial infarction (AMI) and 46 patients with effort angina pectoris (e-AP). Their data were compared with 58 age-matched healthy controls and also compared with 53 patients with vasospastic angina (VSA) as pathological control subjects. Anti-C. pneumoniae specific IgA and IgG antibody titers were measured by enzyme-linked immunosorbent assay (ELISA). The mean indices of IgG-type antibody in AMI and e-AP were not significantly different from those in either the normal controls or VSA group. On the other hand, the mean indices of IgA-type antibody in AMI were significantly higher than in the normal controls (1.39+/-0.83 in AMI vs 0.84+/-0.58 in controls, p<0.001) and VSA (1.39+/-0.83 in AMI vs 1.05+/-0.61 in VSA, p<0.05) group. However, the differences in the IgA titers in the e-AP group compared with the normal controls did not reach a significant level. The odds ratio associated with the seropositivity of IgA for AMI against the normal controls was 3.89 (95% confidence interval (CI): 1.16-13.10) and that against VSA was 6.90 (95% CI: 1.73-27.52) after adjustment for risk factors for CHD and/or age, sex and smoking status. In 6 patients the elevated IgA titers were sustained even at 3 months after the episode of AMI. These results suggest that seropositivity for IgA-type antibody against C. pneumoniae may be a significant risk factor for the development of AMI. The possible mechanisms include chronic inflammation in the coronary artery due to persistent C. pneumoniae infection.

Activation of coagulation in C57BL/6 mice given verotoxin 2 (VT2) and the effect of co-administration of LPS with VT2

To obtain better insight into the pathogenesis of verotoxin-producing Escherichia coli-associated diseases, in this study, we explored the effect of verotoxin 2 (VT2) on coagulation in an animal model. After being given VT2 (50 ng/kg, lethal dose), C57BL/6 mice showed progressively increasing expression of TF mRNA in the kidney and brain and elevated plasma levels of thrombin-antithrombin III complex (TAT), normotest, fibrinogen, and PAI-1 paralleling the disease course over 24 hours; platelet counts were decreased at 48 hours with hemorrhage in the kidney and brain. Co-administration of lipopolysaccharide (LPS, 0.5 mg/kg) with VT2 (50 ng/kg) exhibited more prominant and/or prolonged increase in not only expression of TF and PAI-1 mRNAs in the kidney and brain but also plasma levels of TAT, fibrinogen, and PAI-1 and was associated with more remarkable hemorrhage in the tissues. Although VT2 (5 ng/kg) was not a lethal dose, co-administration of LPS (0.5 mg/kg) with VT2 (5 ng/kg) enhanced the susceptibility to VT2, resulting in more prolonged elevation of TAT levels during the first 24 hours than that in the LPS group and a second elevation at 72 hours, followed by death. Plasma IL-1beta level reached a maximum at 24 hours after VT2 (50 ng/kg) injection prior to the increase in TAT levels, whereas the increase in TNFalpha level immediately after injection was associated with the increase in PAI-1 mRNA. These observations indicate that the activation of coagulation by VT2 may occur through a mechanism different from that used by LPS, since plasma TAT levels rose in the mice immediately after LPS injection and returned to normal over 36 hours.

Whole blood prothrombin time using diluted tissue factor is shortened in spontaneous hypertensive rats

Clinical screening tests for blood coagulation that use plasma as samples cannot estimate the participation of platelets, leukocytes, and erythrocytes in blood coagulation system. We developed an assay to evaluate the total coagulation ability of blood and whole blood prothrombin time (WPT) using the principle of prothrombin time with the diluted-tissue factor as a trigger and a newly developed apparatus, STA, viscosity change detection system (electromagnetic clot detection). The activation of platelets by Ca ionophore shortened WPT and increased the expression of CD62P on the platelet surface. WPTs in citrated blood of spontaneous hypertensive rats (SHR) were significantly shorter than those of controls, Wistar Kyoto rats (WKY). Plasma levels of thrombin-antithrombin III (TAT) in SHR were significantly higher than those of WKY. Moreover, WPT and TAT levels were significantly correlated. Based on these results, WPT was found to be useful to estimate the activation of blood coagulation in whole blood.

Liquid chromatography mass spectrometric analysis of ouabainlike factor in biological fluid

Ouabainlike factor (OLF), assayed as ouabainlike immunoreactivity (OLI), is a probable endogenous digitalislike factor (EDLF). Liquid chromatography/mass spectrometry (LC/MS) is one of the most highly sensitive tools for obtaining structural information regarding low-molecular weight materials in a target compound, and to measure the concentrations of these materials. We have previously reported that OLI can be isolated from the culture supernatant of the rat pheochromocytoma cell line, PC12, by several reverse-phase chromatography and LC/MS techniques. The present study was performed to characterize OLF from biological fluids such as plasma and culture supernatant of PC12 cells by LC/MS. The previous applications of LC/MS to OLI in plasma have been limited to structural identification at the final stages of isolation, in which the starting volume of plasma has been over 10 I. In the present study, we tried to minimize the volume of plasma, and to develop a new preclearing step to gain adequate LC/MS characterization using MS/MS analysis. The plasma was acidified, and OLI was purified by ODS column chromatography. OLI in chromatographic fractions from plasma was assayed by a sensitive enzyme-linked immunosorbent assay for ouabain. After Sep-Pak treatment and two rounds of ODS column chromatography, OLI was identified from 80 ml of plasma. The structure of the purified OLI was identical to authentic ouabain and digoxin, as assessed by LC/MS. In conclusion, we identified the chemically or structurally clarified ouabain and digoxin as the circulating form in plasma by LC/MS.

A novel type of factor XI deficiency showing compound genetic abnormalities: a nonsense mutation and an impaired transcription

We studied a 29-year-old Japanese male patient with factor XI deficiency; we also studied his parents and one sibling. Factor XI coagulation activity and antigen levels were extremely low (less than 1% of normal level) in both the patient and his brother, and they were half the normal levels in both parents. Sequence analysis of all 15 exons and the exon-intron boundaries of the factor XI gene amplified by polymerase chain reaction revealed a nonsense mutation in exon 8 (Gln263-->Stop). Although the parents are first cousins, the mutation was unexpectedly heterozygous in all the family members except the father, who showed the homozygous wild type, indicating that this mutation alone was not sufficient to account for the factor XI deficiency. To explore the genetic abnormality in the father, we analyzed allele-specific expression of the platelet factor XI gene using reverse transcription-polymerase chain reaction and subsequent restriction enzyme digestion. As a result, gene expression from only one allele was severely impaired in the father. This result implies an additional mutation in some regulatory element of the factor XI gene from paternal inheritance. We concluded that the factor XI deficiency of the patient was caused by compound heterozygous genetic abnormalities.

Increases in plasma ouabainlike immunoreactivity during surgical extirpation of pheochromocytoma

The ouabainlike factor (OLF) is thought to be an important modulator of salt and water metabolism. Plasma OLF could be derived from the central nervous system and/or the adrenal gland. Since the adrenal medulla is of neural origin, the cytology of pheochromocytoma of adrenomedullary origin resembles that of neuronal cells. Ouabainlike immunoreactivity (OLI) is, in fact, present in the adrenal medulla as shown by immunohistochemistry. The plasma levels of catecholamines and OLI were significantly elevated during surgical extirpation of pheochromocytoma in this case. To clarify the origin of circulating OLI in a patient with pheochromocytoma, the relationship between plasma OLI and catecholamines during adrenalectomy was investigated. Plasma catecholamine levels exceeded the normal reference interval, and plasma OLI was positively correlated with the patient's plasma level of norepinephrine. The peak level during operation was about 10 times higher than the baseline level. Both levels reached a maximum when the tumor was mechanically pressed, and then gradually decreased thereafter. The level of OLI in the tumor was higher than that of the normal adrenal cortex. When OLI in the tumor was characterized by reversed-phase high-performance liquid chromatography, the retention time of OLI corresponded with that of authentic ouabain. These results suggest that the circulating OLI in this patients was derived mainly from the pheochromocytoma of adrenomedullary origin.

Molecular characterization of total kininogen deficiency in Japanese patients

Kininogens are multifunctional plasma glycoproteins. There are two forms of human kininogen: low molecular weight kininogen (LK) and high molecular weight kininogen (HK). Both are derived from the same gene by alternative splicing. Some patients with kininogen deficiency have been reported to be deficient only in HK while others are deficient in both HK and LK (total kininogen deficiency). We analyzed three Japanese patients with total kininogen deficiency by the Csp45I digestion study of exon 5 as previously reported in Williams trait and found that two had the same point mutation of C to T at base 22 of exon 5, resulting in a transition of CGA (Arg) codon to TGA (Stop) codon. This is the first report of molecular characterization of total kininogen deficiency in the Japanese population.

Preexisting membranous nephropathy in allograft kidney

A case of membranous nephropathy, preexisting in a donor kidney, will be reported. A 41-year-old man underwent a cadaver renal transplantation. An allograft biopsy specimen obtained during the operation showed spike formation on periodic acid-silver methenamine staining and deposition of IgG along the glomerular capillary loop on immunoperoxidase staining. Immunofluorescence staining for IgG remained in the specimens obtained on day 11 and after 4 weeks, but markedly decreased in the specimen obtained 7 weeks after transplantation. Electron-dense deposits also decreased in amount, but irregular thickening of the glomerular basement membrane with spikes, electron-lucent washout lesions, and small amounts of electron-dense deposits remained 20 months after the transplantation. These findings suggest that membranous nephropathy, as well as IgA nephritis and diabetic nephropathy, resolve after renal transplantation and that deposition of IgG markedly decreases within a few months after transplantation, but that complete histological restoration of the basement membrane needs at least a few years.

Expression of functional tissue factor on small vesicles of lipopolysaccharide-stimulated human vascular endothelial cells

We examined tissue factor expression on lipopolysaccharide-stimulated endothelial cells and their small vesicles by using specific antibodies and flow cytometry. Tissue factor functional activity was also assessed by activation of factor X. Endothelial cells were stimulated with 10 microg/ml of lipopolysaccharide in M-199/bovine serum albumin. Flow cytometry showed that expression of tissue factor on endothelial cells reached a maximum at 6 hours after stimulation, whereas that on small vesicles reached a maximum after 12 hours. Factor X activation mediated by factor VIIa and tissue factor was observed over a similar time course and was inhibited by the addition of antitissue factor antibody. Immunoelectron microscopy suggested that small vesicles with expression of some tissue factor were produced from the surface of endothelial cells. Our findings thus showed that tissue factor on endothelial cells produced by lipopolysaccharide stimulation was partly released to small vesicles. This may cause disseminated intravascular coagulation and related coagulation disorders.

Purification and characterization of ouabain-binding protein in human plasma

Ouabainlike factors are thought to be a kind of important modulators of salt and water metabolism in essential hypertension. We purified the binding-protein of ouabain (OBP) from human plasma. The amino-terminal sequence of OBP from human plasma, (NH2-TLGQPREPQVYTLPPXREEM-), indicated that OBP is the carboxy-terminal fragment (14.4 kDa by SDS-PAGE) from T218 of IgG2 heavy chain and from A221 of the IgG1 heavy chain constant region. Moreover, plasmin-cleaved Fc fragment (pFc) of IgG possessed the ouabain-binding activity by the gel-filtration method of pFc and authentic ouabain mixture, whereas neither intact, aggregate, nor papain-cleaved Fc fragment did. The amino-terminal sequence of pFc was NH2-THTXPPXPAPELLGGPXVFL-, and this sequence corresponded to the T105 to L125 fragment of the IgG1 heavy chain constant region. The growth of cultured THP-1 cells were arrested in the dose-dependent manner by ouabain, which was inhibited by the addition of 20 microg/mL of pFc. These results suggested that plasmin-cleaved Fc of human IgG is one of the binding protein of ouabain/ouabainlike factor(s) in human plasma.

[Atherosclerosis and activation of platelet and blood coagulation]

It is widely accepted that atherosclerosis and thrombus formation are closely associated. Recent progress in the development of molecular markers of blood coagulation and platelet enabled us to estimate even the slight activation of blood coagulation and platelet activation systems. We investigated a contract phase-activate coagulation and factor -inhibitor complex (factor XIa-alpha 1 antitrypsin) and expression of CD62P on platelet surface, a specific antigen on platelet, in patients with coronary arterial diseases. We compared these activation markers after stratifying patients according to the number of significant coronary artery stenoses. Patients with three-vessel disease had significantly increased levels of factor XIa-alpha 1 antitrypsin, fibrinogen, and CD62P expression compared to those in other subgroups. Although it is unknown whether these abnormalities are the cause or the result of the vascular lesion, these findings may be important to understand the pathophysiology underlying atherosclerosis or propagation of the atherosclerotic process itself.

[Anti-fibrinogen antibody detected in a patient with systemic lupus erythematosus and disseminated intravascular coagulation]

A 22-year-old woman was admitted to our hospital with fever, generalized lymphadenopathy, and pancytopenia in February 1995. She was diagnosed as having systemic lupus erythematosus (SLE) based on positivity for anti-nuclear antibody, and polyarthritis among other findings. A diagnosis of disseminated intravascular coagulation (DIC) was made based on the increase of FDP and other data (DIC score: 7). We also detected an anti-fibrinogen antibody. Lymph node biopsy revealed subacute necrotizing inflammation and there were on signs of the hemophagocytic phenomenon in bone marrow. The DIC score improved and the anti-fibrinogen antibody disappeared in association with the response of SLE to prednisolone therapy. The onset of SLE associated with DIC has never been reported before, as far as we could determine. The mechanism of DIC associated with SLE may be related to endothelial damage caused by immune complexes.

[A case of osteopetrosis with an abnormal CK-MB/T-CK ratio]

Creatine kinase (CK)-MB subunit has been recognized as a useful marker for acute myocardial infarction (AMI). However, we recently experienced one case of osteopetrosis with moderately high CK-MB and an abnormal (more than 100%) CK-MB/total (T)-CK ratio without evidence of AMI in a medical examination. We have already experienced 17 cases with an abnormal CK-MB/T-CK ratios in addition to the present case. Those cases were patients with malignant tumor with metastasis (n = 13), leukemia (2), liver cirrhosis (1), and cerebral death (1), and thereby the band of macro-CK was found in the electrophoresis. However, we detected neither the band of macro-CK nor the abnormal levels of tumor markers such as CEA, alpha-fetoprotein, CA-19-9 in the present case. Instead of the macro CK, the high level of CK-BB was detected in electrophoresis. In the medical examination, especially in screening tests, the CK-MB was generally assayed with use of the immunoinhibition method in automated analyzers. The method principle was based on the absence of CK-BB in the patient serum. Since the patient had the past history of pathological fracture in his boyhood, this patient was diagnosed as osteopetrosis. These results suggest that we must consider the possibility of osteopetrosis when an abnormal CK-MB and CK-MB/T-CK ratio without evidence of serious diseases were found. This is simply because of the assay method of immunoinhibition for CK-MB activity.

[Shear stress and platelet-derived microparticles]

One of the responses of activated platelets to certain stimuli is the shedding of microparticles. Many studies have attempted to characterize the role of microparticles under various clinical situations or experimental conditions. Pathological levels of fluid shear stress may occur in diseased small arteries and arterioles partially obstructed by atherosclerosis or vasospasm and such shear stress may induce the activation and aggregation of circulating platelets. We investigated whether high shear stress could cause both platelet aggregation and shedding of microparticles from the platelet plasma membrane. A cone-plate viscometer was used to apply shear stress and microparticle formation was measured by flow cytometry. It was found that microparticle formation increased as the duration of shear stress increased. Both microparticles and remnant platelets showed procoagulant activity on their surfaces. Investigation of the mechanisms involved in shear-dependent microparticle generation showed that binding of von Willebrand factor to platelet glycoprotein Ib, influx of extracellular calcium, and activation of platelet calpain were required to generate microparticles under high shear stress conditions. Activation of protein kinase C promoted shear-dependent microparticle formation. These findings suggest that local generation of microparticles in atherosclerotic arteries, the site at which pathological levels of shear stress could occur, contributes to arterial thrombosis by providing and expanding a catalytic surface for the coagulation cascade.

Effect of a new monoclonal anti-glycoprotein IX antibody, KMP-9, on high shear-induced platelet aggregation

Human platelet glycoprotein Ib/IX complex acts as a receptor for von Willebrand factor. It is widely accepted that glycoprotein Ib is the essential receptor component, but the role of glycoprotein IX is still unclear. We produced a new monoclonal anti-glycoprotein IX antibody (KMP-9) by the hybridoma technique using platelets from a patient with Glanzmann's thrombasthenia. The epitope of KMP-9 was localized to the C-terminal 8 kD fragment of glycoprotein IX using ELISA analysis of polyethylene-pin-synthesized peptides, as well as Western blot analysis of platelets after digestion with N-glycosidase and Staphylococcus aureus V8 protease. KMP-9 partially inhibited high shear stress-induced platelet aggregation, but had no effect on aggregation induced by ristocetin or low shear stress. Its inhibitory effect on high shear stress-induced aggregation was weaker than that of anti-glycoprotein Ib or anti-glycoprotein IIb/IIIa monoclonal antibodies. A 21-mer synthetic peptide (glycoprotein IX L110-G130) inhibited the binding of KMP-9 to platelets. It also competively inhibited the suppression of high shear stress-induced platelet aggregation by KMP-9, but had no direct effect on this aggregation. KMP-9 may be useful to clarify the physiological role of GPIX.

Vasodepressor effects of exercise are accompanied by reduced circulating ouabainlike immunoreactivity and normalization of nitric oxide synthesis

Our object was to evaluate the effects of regular mild exercise on blood pressure and on circulating level of ouabainlike factors (OLF) and of nitrate anion, an endproduct of nitric oxide (NO) in humans. We measured plasma ouabainlike immunoreactivity (OLI) and nitrate ions (NO3.) before and after mild exercise for 3 months' duration in 16 patients with essential hypertension, diabetes mellitus, obesity, or hyperlipidemia. Plasma OLI was measured using an amplified ELISA system with anti-ouabain antibody and biotinyl-tyramide. Serum NO3. was measured with high-performance liquid chromatography (HPLC) with an anion-exchange column. With the reverse phase HPLC system with an octa decylsilyl silicagel column, the elution volume of plasma OLI of a healthy volunteer matched that of authentic ouabain in a gradient elution system of acetonitrile/H2O. Plasma OLI levels decreased significantly by about 34% after mild exercise, and NO3. levels tended to be within the reference interval in normal volunteers. Body weight, diastolic and systolic blood pressure, serum triglyceride and acetylcholine esterase (a marker of the fatty liver) were significantly decreased (p < 0.01) after 3 months of regular mild exercise. The plasma OLI level was significantly correlated with plasma NO3., there was a trend toward a correlation with diastolic blood pressure (p = 0.06) before and after regular exercise. Regular mild exercise led to a decrease in plasma levels of OLI, and acetylcholine esterase activity and blood pressure in adult patients. Results suggest that changes in OLF production contribute to the blood pressure regulation seen in patients who exercise regularly.

Tyrosine phosphorylation and p72syk activation by an anti-glycoprotein Ib monoclonal antibody

NNKY5-5, an IgG monoclonal antibody directed against the von Willebrand factor-binding domain of glycoprotein (GP) Ib alpha, induced weak but irreversible aggregation (or association) of platelets in citrate-anticoagulated platelet-rich plasma. This phenomenon was defined as small aggregate formation (SAF). Platelets in hirudin-anticoagulated plasma or washed platelets showed little response to NNKY5-5 alone, but the antibody potentiated aggregation induced by low concentrations of adenosine diphosphate or platelet-activating factor. NNKY5-5 did not induce granule release or intracellular Ca2+ mobilization. However, NNKY5-5 caused tyrosine phosphorylation of a 64-kD protein and activation of a tyrosine kinase, p72syk. An anti-Fc gamma II receptor antibody had no effect on SAF, suggesting that NNKY5-5 activated platelets by interacting with glycoprotein Ib. Fab' fragments of NNKY5-5 did not induce SAF, but potentiated aggregation induced by other agonists. The Fab' fragment of NNKY5-5 induced the activation of p72syk, suggesting that such activation was independent of the Fc gamma II receptor. Cross-linking of the receptor-bound Fab' fragment of NNKY5-5 with a secondary antibody induced SAF. GRGDS peptide, chelation of extracellular Ca2+, and an anti-GPIIb/IIIa antibody inhibited NNKY5-5-induced SAF, but had no effect on 64-kD protein tyrosine phosphorylation or p72syk activations. Various inhibitors, including aspirin and protein kinase C, had no effect on SAF, protein tyrosine phosphorylation, or p72syk activation. In contrast, tyrphostin 47, a potent tyrosine kinase inhibitor, inhibited NNKY5-5-induced SAF as well as tyrosine phosphorylation and p72syk activation. Our findings suggest that binding of NNKY5-5 to GPIb potentiates platelet aggregation by facilitating the interaction between fibrinogen and GPIIb/IIIa through a mechanism associated with p72syk activation and tyrosine phosphorylation of a 64-kD protein.

Daidzein stimulation of bone resorption in pit formation assay

We found that daidzein stimulated bone resorption in the pit formation assay at the concentration of 10(-8)-10(-10) M. On the other hand, genistein and ipriflavone at these concentrations did not have any effect on pit formation. We speculated that daidzein had the ability to induce osteoclasts directly or indirectly from their progenitors and might be a tool by study osteoclast differentiation.

Flow cytometric analysis of platelet activation markers CD62P and CD63 in patients with coronary artery disease

We investigated whether platelet activation could be quantitatively detected in patients with coronary artery disease using flow cytometric analysis of the expression of CD62P and CD63, which are activation-specific antigens on the platelet surface. Platelet samples were obtained from 16 healthy control subjects and 65 patients, of whom 25 had angiographically normal coronary arteries and 40 had at least one major coronary artery stenosis (> or = 50% narrowing). In both patient groups, CD62P expression was significantly higher than in the control group, but the difference between the two patient groups was not significant. In contrast, CD63 expression did not differ among the three groups. We also compared expression of these antigens after stratifying the patients according to the number of significant coronary artery stenoses. Patients with three-vessel disease had significantly increased CD62P and CD63 expression compared with the other subgroups. Our findings indicate that platelet activation occurs in patients with severe coronary artery stenosis.

High shear stress can initiate both platelet aggregation and shedding of procoagulant containing microparticles

Previous studies have demonstrated that a high level of shear stress can produce platelet aggregation without the addition of any agonist. We investigated whether high shear stress could cause both platelet aggregation and shedding of microparticles from the platelet plasma membrane. A coneplate viscometer was used to apply shear stress and microparticle formation was measured by flow cytometry. It was found that microparticle formation increased as the duration of shear stress increased. Both microparticles and the remnant platelets showed the exposure of procoagulant activity on their surfaces. Investigation of the mechanisms involved in shear-dependent microparticle generation showed that binding of von Willebrand factor (vWF) to platelet glycoprotein lb, influx of extracellular calcium, and activation of platelet calpain were required to generate microparticles under high shear stress conditions. Activation of protein kinase C (PKC) promoted shear-dependent microparticle formation. Epinephrine did not influence microparticle formation, although it enhanced platelet aggregation by high shear stress. These findings suggest the possibility that local generation of microparticles in atherosclerotic arteries, the site that pathologically high shear stress could occur, may contribute to arterial thrombosis by providing and expanding a catalytic surface for the coagulation cascade.

Association of tissue factor with a gamma chain homodimer of the IgE receptor type I in cultured human monocytes

Tissue factor (TF) is a high-affinity receptor for coagulation factors VII (F VII) and VIIa. The F VII/VIIa/TF complex is the major cellular initiator of the extrinsic coagulation cascade. We found that the occupancy of TF by its ligand, F VIIa, is involved with signal transduction and that TF is associated with the gamma chain homodimer identified as a component of IgE receptor type I (Fc epsilon RI). When 4-day cultured human monocytes were incubated with F VIIa, several polypeptides, especially a 70-kDa polypeptide, were transiently phosphorylated on tyrosine, residues. These phosphorylation events were inhibited by prior binding of anti-TF monoclonal antibody (mAb) HTF-K14, but not anti-TF mAb HTF-K180 to intact cultured monocytes. HTF-K14 blocked the binding of F VII/ VIIa to cell surface TF, whereas HTF-K180 did not. Anti-TF immunoprecipitates prepared from 1% digitonin lysates of cultured human monocytes incorporated phosphate in a gamma chain homodimer when incubated with [gamma-32P] ATP. The identity of the T-associated structures as gamma chains was established by immunoblot analysis of anti-TF mAb immunoprecipitates with anti-gamma chain mAb. In addition, anti-TF immunoblot analysis showed that TF co-precipitated with anti-gamma chain mAb. Our data suggest that gamma chains may play an important role in signaling via TF in human monocytes/macrophages.

[Evaluation of the factor XIIa assay kit]

The assay for activated coagulation factors has recently been considered to be a useful tool for detecting hypercoagulable state. Measurement of activated factor XI and alpha 1 antitrypsin complex developed by us is the only one measure for detecting contact phase hypercoagulation. The ACTIVATED FACTOR XII kit (Shield Diagnostics) has recently been commercially available, and the reference range was reported in the instruction manual. However, because the recovery rate of purified factor XIIa (XIIa) in normal pooled plasma by this assay kit was strikingly decreased, the effects of inhibitors in plasma, such as low molecular weight serine proteinase inhibitor (diisopropyl fluoro-phosphate, DFP), the specific inhibitor for XIIa (corn trypsin inhibitor, CTI), the main inhibitor for XIIa (C1 inhibitor, C1I) were examined. These three inhibitors and XIIa were incubated for 18 hours, then the XIIa levels of these complexes and the recovery rate in the normal pooled plasma were assayed by this assay kit. The recovery ratios in the normal pooled plasma were; DFP-XIIa 82%, CTI-XIIa 63%, and C1I-XIIa 0%, XIIa without inhibitor 7%. These results suggest that this XIIa kit does not reflect the levels of complexed form of XIIa and inhibitors in plasma samples.

Effects of intracerebroventricular administration of 6-hydroxydopamine on ouabain-like immunoreactivity in plasma and the hypothalamo-pituitary axis in rats

OBJECTIVE

To examine the role of central mechanisms on the production and release of an ouabain-like factor, the effects of intracerebroventricular injections of 6-hydroxydopamine on the tissue content and on the plasma level of the ouabain-like factor were determined in rats.

METHODS

The vehicle (0.1% ascorbic acid in 0.9% saline) and 6- hydroxydopamine (250 micrograms/rat) were injected into the left lateral ventricle in ether-anaesthetized Wistar rats. Hypothalamus, pituitary, adrenal and venous blood was sampled 24h and 7 days later. The procedure was repeated using another rat group 7 days later. Characteristics of immunoreactive ouabain-like factor were determined by a combination of high-performance liquid chromatography and a highly sensitive enzyme-linked immunosorbent assay for ouabain. The level of the ouabain-like factor in these tissues and in plasma extracts measured by the enzyme-linked immunosorbent assay was compared between the two groups receiving 6-hydroxydopamine and the vehicle.

RESULTS

Twenty-four hours after the intracerebroventricular injections of 6-hydroxydopamine, the ouabain-like factor level in the pituitary, hypothalamus and plasma had decreased significantly, whereas the ouabain-like factor level in the adrenal had not changed. The content of noradrenaline in the hypothalamus was also decreased markedly 7 days later and the content of ouabain-like factor in the pituitary remained low. On liquid chromatography the elution pattern of the ouabain-like factor in plasma and in tissue extracts coincided with that of authentic ouabain.

CONCLUSIONS

Intracerebroventricular treatments with 6-hydroxydopamine elicited decreases in ouabain-like factor contents in the pituitary, the hypothalamus and the plasma. These results suggest that the production and release of ouabain-like factor are closely associated with the brain, particularly the hypothalamus-pituitary axis, and that noradrenergic or dopaminergic neurons, or both, play a key role in this mechanism.

High-density lipoprotein inhibits the synthesis of platelet-activating factor in human vascular endothelial cells

The regulation of platelet-activating factor (PAF) synthesis by serum lipoproteins was investigated in human umbilical vein endothelial cells. High-density lipoprotein (HDL) inhibited PAF synthesis in agonist (thrombin, histamine, and A23187)-stimulated endothelial cells, that was determined by incorporation of [3H]acetate into PAF and by bioassay. The inhibition by HDL was increased in a concentration-dependent manner, but was reversed as the concentration of thrombin increased. HDL did not affect the time course of PAF production. HDL lipids suppressed the PAF production to a lesser extent than HDL. The reduction of PAF accumulation in HDL, did not result from degradation of PAF but inhibition of PAF synthesis, which was mainly mediated via the blockade of acetyl-CoA:1-alkyl-2-lyso-sn-glycero-3-phosphocholine acetyltransferase activation. HDL did not prevent the release of [3H]arachidonic acid in thrombin-stimulated endothelial cells. The binding of 125I-HDL to endothelial cells and its uptake were not enhanced by thrombin stimulation. These results demonstrate that HDL may inhibit the activation of acetyltransferase by thrombin at the cell surface. This observation may explain a part of mechanism of HDL action.

Participation of alpha IIb beta 3 in platelet microparticle generation by collagen plus thrombin

We investigated the role of alpha IIb beta 3 in microparticle generation by normal and thrombasthenic platelets stimulated with collagen plus thrombin. Microparticle generation by normal platelets was scarcely inhibited by monoclonal antibodies for glycoprotein Ib and glycoprotein IX. Although one monoclonal anti-alpha IIb beta 3 antibody (NNKY1-32) partly inhibited microparticle generation, 3 other monoclonal anti-alpha IIb beta 3 antibodies had little effect. However, the combination of 4 monoclonal anti-alpha IIb beta 3 antibodies or treatment with a polyclonal anti-alpha IIb beta 3 antibody significantly inhibited microparticle generation (p < 0.05). Microparticle generation by thrombasthenic platelets also occurred after stimulation with collagen plus thrombin, although at a significantly lower level compared with normal platelets. Monoclonal antibodies for resting alpha IIb beta 3, P-selectin, activated alpha IIb beta 3 and beta 2-glycoprotein I bound to microparticles from healthy platelets. In contrast, only a monoclonal antibody for beta2-glycoprotein I bound to thrombasthenic microparticles. These results suggest that microparticle generation by collagen plus thrombin occurs via two different mechanisms which are dependent and independent of alpha IIb beta 3, respectively. The alpha IIb beta 3-dependent mechanism appears to require activation of alpha IIb beta 3.

Expression of prothrombinase activity and CD9 antigen on the surface of small vesicles from stimulated human endothelial cells

We employed flow cytometry and monoclonal antibodies (MoAb) to study the surface membrane protein of shed particles (small vesicles, SV) that were released from vascular endothelial cells (EC) by agonists such as a Ca ionophore (A23187) and thrombin. After stimulation of EC by A23187, CD9 antigens disappeared entirely from the EC surface in a time- and concentration-dependent manner; they subsequently moved onto the SV surface. Von Willebrand factor (vWF) and P-selectin from Weibel-Palade (W-P) bodies were expressed rapidly on the EC surface after thrombin stimulation, but not on the SV surface. P-selectin may have some effect on maintenance of hemostasis on the EC surface. We demonstrated that the surfaces of SV and EC significantly supported prothrombinase activity and confirmed that A23187-induced SV from EC express binding sites for factors IXa and Xa. These results suggest that the SV are an important factor in a novel controlling mechanism of the coagulation system on the EC surface.

[Activated coagulation factors in various thrombotic diseases]

Various hemostatic abnormalities have been reported and excess activation of coagulation factors, such as prothrombin, factor VII, factor IX, and factor XI, have been detected in thrombotic diseases states by various assay systems. We recently developed the enzyme-linked differential immunoassay for activated factor XI-alpha 1 antitrypsin complex (FXIa-alpha 1 AT) and applied it with other assays for activated factors such as thrombin-antithrombin III complex (TAT) to detect the hypercoagulable state in clinical samples. In patients with DIC, the FXIa-alpha 1 AT level in plasma increased before onset of DIC. In patients with non-insulin-dependent diabetes mellitus, FXIa-alpha 1AT and TAT levels were increased in the patient plasma. FXIa-alpha 1AT was related to the severity of urinary albumin excretion, whereas TAT was not. Plasma FXIa-alpha 1AT levels were significantly increased in patients with angiographically proven coronary artery disease, and showed a positive correlation with TAT, fibrinogen, and Lp(a). Evaluation of activated coagulation factor provides useful information on the diagnosis of thrombotic disease.

Mechanism of hypertension induced by chronic inhibition of nitric oxide in rats

In order to clarify the mechanism of hypertension induced by a nitric oxide (NO) synthase inhibitor, L-NG-nitro-L-arginine (LNNA), metabolites of NO, catecholamines, and hemodynamic parameters were measured during 7 days of oral administration of LNNA in rats. Control rats received either L-arginine (L-Arg) or the vehicle. systolic blood pressure, measured by the tall-cuff method was elevated throughout the period of LNNA administration, but that in the two control groups was not influenced by treatment. Heart rate decreased on the second day only in LNNA-treated rats. Although L-Arg treatment had no influence, LNNA markedly decreased the plasma level and the urinary excretion of nitrate ions (NO-3). Urinary excretion of noradrenaline was significantly decreased on the second day of LNNA administration and returned to the control level thereafter. When hemodynamic changes were measured by using radioactive microspheres, LNNA was found to increase blood pressure by markedly increasing total peripheral resistance. Cardiac output was decreased by LNNA. L-Arg, again, did not influence the hemodynamic variables as compared with the vehicle control group. The regional vascular resistance index was increased by LNNA in many tissues and organs, except the brain and the heart. Regional blood flow, on the other hand, was significantly decreased only in the liver and skin by LNNA. The marked reduction in NO3- in urine by LNNA-treatments may indicate that the measured NO3- is exclusively of endogenous origin, and that inhibition of NO production causes elevation of blood pressure by constricting peripheral arteries. Sympatholytic responses by the baroreceptor reflex were thereby evident only on the second and the third days, which was indicated by bradycardia and suppression of noradrenaline excretion into urine. These results indicate that the inhibition of NO synthase actually decreases production of endogenous NO, and that the hypertension caused by decreases in NO production is due to elevation of total peripheral vascular resistance.

Evaluation of factor XIa-alpha 1-antitrypsin in plasma, a contact phase-activated coagulation factor-inhibitor complex, in patients with coronary artery disease

Excess activated factor XI (FXIa) in plasma indicates increased activation during the contact phase of blood coagulation. To investigate the relationship between such elevations and coronary atherosclerosis, we examined FXIa values in patients with coronary artery disease (CAD) by an enzyme-linked immunosorbent assay method that we developed that detects FXIa in plasma samples as an FXIa-alpha 1-antitrypsin complex (FXIa-alpha 1AT). The presence and extent of CAD were documented by coronary angiography and assessed by a recently developed scoring system for semiquantitative estimation of coronary atherosclerosis. Plasma FXIa-alpha 1AT levels were significantly increased in patients with angiographically proven CAD (13.9 +/- 3.0 micrograms/L, n = 42) compared with age-matched, healthy control subjects (11.9 +/- 1.7 micrograms/L, n = 20) as well as patients with angiographically normal coronary arteries (12.0 +/- 2.3 micrograms/L, n = 25). Moreover, in the total patient population, the FXIa-alpha 1AT level was related to the number of significant coronary artery stenoses as well as to the total coronary score. FXIa-alpha 1AT showed a positive correlation with thrombin-antithrombin III complex, fibrinogen, and Lp(a) and an inverse correlation with apo A-I, as determined by multi-variate analysis. Our studies provide evidence that increased activation of the contact pathway occurs in patients with CAD and is related to the severity of the disease. Although it is unknown whether this abnormality is the cause or the result of the vascular lesion, it may be important for progression of the underlying atherosclerosis or for propagation of the atherosclerotic process itself.

Regulation of the tertiary structure and function of coagulation factor IX by magnesium (II) ions

The indispensable role of Ca2+ ions in the maintenance of the functional tertiary structures of vitamin K-dependent coagulation factors has been definitively established but the participation of Mg2+ ions, another alkaline-earth metal that is present abundantly in blood plasma, in such a process is not yet understood. We show here that the Ca(2+)-stabilized conformation of coagulation factor IX undergoes a further conformational change upon binding of Mg2+ ions using three independent structural probes. The probes we used were (i) IX/X-bp, a snake venom anticoagulant that recognizes the Gla domains in coagulation factors IX and X, (ii) conformation-specific polyclonal antibodies against bovine factor IX, and (iii) monoclonal antibodies against the Gla domain of human factor IX. The binding of all these probes had an absolute requirement for Ca2+ ions, and Mg2+ ions alone were ineffective. However, when added together with Ca2+ ions, Mg2+ ions at physiological concentrations greatly augmented the binding of these probes to factor IX; the required concentration of Ca2+ ions was much reduced, and the affinity of each probe for factor IX was increased even in the presence of an excess of Ca2+ ions. These results suggest the presence of a Mg(2+)-specific binding site that does not interact with Ca2+ ions in factor IX. Furthermore, Mg2+ ions potentiated the susceptibility of factor IX to activation by factor XIa, concomitant with their effect on the conformation. Similarly, the required Ca2+ concentration was reduced by Mg2+ ions, and the rate of conversion to factor IXa was increased by Mg2+ ions in the presence of an excess of Ca2+ ions. At a saturating concentration of Ca2+ ions (5 mM), addition of 1 mM Mg2+ reduced the apparent Km value for factor IX from 0.31 to 0.18 microM, and in the presence of a physiological concentration of Ca2+ ions (1 mM), the reduction in Km by Mg2+ ions was far more striking (from 0.91 to 0.24 microM). The apparent Vmax values were hardly affected by Mg2+ ions. Our present data reveal a hitherto novel physiological role of the Mg2+ ions in plasma. Not only Ca2+ ions but also Mg2+ ions are important regulators of the stabilization of the native conformation of factor IX as well as of its efficient activation.

Activation of hepatocyte growth factor by two homologous proteases, blood-coagulation factor XIIa and hepatocyte growth factor activator

Hepatocyte growth factor (HGF) is secreted as an inactive single-chain precursor from the producing cells, and normally remains in this form associated with the extracellular matrix. In response to tissue injury, the single-chain precursor is converted to a biologically active heterodimer by a serine protease, the activity of which is induced in the injured tissue. We have previously identified HGF activator, a serum serine protease that activates single-chain HGF. The sequence of HGF activator cDNA revealed that the HGF activator is homologous to blood-coagulation factor XIIa. In this study, we found that coagulation factor XIIa has an ability to activate single-chain HGF. Factor XIIa exhibited a significant level of HGF-converting activity in the presence of dextran sulfate, although the specific activity of factor XIIa was slightly lower than that of the HGF activator. Since factor XIIa is activated during the initiation of contact activation induced by tissue injury, factor XIIa may function as an HGF-converting enzyme together with HGF activator in the injured tissue. C1-inhibitor, antithrombin III and alpha 2-antiplasmin, that regulate the blood-clotting activity of factor XIIa, were also effective against the HGF-converting activity of factor XIIa. Furthermore, factor XIIa was not active in the HGF-converting activity in serum. Thus, the HGF-converting activity of factor XIIa may be regulated by these serum inhibitors.

Relationship of microparticles with beta 2-glycoprotein I and P-selectin positivity to anticardiolipin antibodies in immune thrombocytopenic purpura

We investigated the association of beta 2-glycoprotein I and P-selectin with platelet-derived microparticles in 48 patients with immune thrombocytopenic purpura and 20 normal controls using two-color flow cytometric analysis. In addition, anticardiolipin antibodies were detected by an enzyme-linked immunosorbent assay. Platelet microparticles from the patients showed a higher positivity for beta 2-glycoprotein I than those from the normal controls (23.1 +/- 15.4% vs. 5.3 +/- 3.1%, p < 0.01), but this positivity was not related to the presence of platelet-associated IgG or to the severity of thrombocytopenia. In the 18 patients with more than 20% P-selectin-positive microparticles, beta 2-glycoprotein I positivity was significantly higher than in the 30 patients with less than 20% P-selectin-positive microparticles (37.1 +/- 20.5% vs. 21.5 +/- 17.3%, p < 0.01). In addition, anticardiolipin antibodies were detected in eight patients, and they had a significantly higher level of beta 2-glycoprotein I-positive microparticles than the patients without such antibodies (42.0 +/- 22.9% vs. 22.6 +/- 18.9%, p < 0.05). Our results suggest that anticardiolipin antibodies activate platelets in immune thrombocytopenic purpura and cause the generation of microparticles rich in beta 2-glycoprotein I and P-selectin. These microparticles may then act to regulate coagulation abnormalities in patients with anticardiolipin antibodies.

Amyloid beta-protein precursor-rich platelet microparticles in thrombotic disease

We investigated the association of amyloid beta-protein precursor (APP) and platelet derived microparticles in 20 normal controls and 91 patients with various diseases causing a thrombotic tendency. Compared with the controls, the mean percentage of APP-positive microparticles was significantly greater in the patients with cerebral infarction (39.1 +/- 17.7%, p < 0.001), diabetes (31.1 +/- 12.6%, p < 0.001), and uremia (30.1 +/- 14.7%, p < 0.01), but not in those with hypertension (8.2 +/- 6.3%, p = NS). Sixteen patients with cerebral infarction, 20 with diabetes, and 11 with uremia had microparticles with very high APP levels. In normal controls, 7.2 +/- 3.7% of the microparticles were positive for P-selectin, while the percentage in cerebral infarction, diabetes, uremia, and hypertension was respectively 43.5 +/- 15.1%, 40.0 +/- 12.8%, 31.8 +/- 12.2%, and 11.6 +/- 7.3%. There was a significant correlation between P-selectin and APP positivity of microparticles. Our results suggest that microparticle APP may have a regulatory influence on coagulation abnormalities.

Anti-obesity and anti-diabetic effects of carteolol in non-insulin-dependent diabetic mice

1. When carteolol, a beta-adrenergic blocker, was administered to KK-Ay/Ta Jc1 mice that are obese and develop spontaneously non-insulin dependent diabetes, their increase in bodyweight was arrested from the age of 16 weeks. Since their intake of food and water was not influenced by carteolol treatment, compared with the control KK-Ay/Ta Jc1 mice, abolition of the weight gain might be attributed to increased energy metabolism. 2. Non-fasting serum glucose levels in carteolol-treated mice at the age of 17 weeks were within normal range (118 +/- 4 vs 186 +/- 12 mg/dL). An intraperitoneal glucose-tolerance test revealed that the carteolol treatment markedly restored glucose metabolism; fasting plasma glucose (88 +/- 6 mg/dL) was within normal range, and immunoreactive insulin (IRI; 5.8 +/- 0.8 vs 33.3 +/- 10.5 ng/mL) and plasma glucose levels at 60 min post glucose (361 +/- 44 vs 541 +/- 32 mg/dL) were significantly lower in carteolol-treated mice than those in the control group at the age of 20 weeks. 3. From these findings, carteolol is considered to have little effect on the growth of mice but to correct the obesity that develops after age 16 weeks, when their growth terminates. In addition, the normalization of blood glucose and marked decrease in IRI levels suggests that carteolol improves glucose tolerance by increasing the insulin sensitivity. 4. Since brown adipose tissue (BAT) is closely associated with thermogenesis and energy consumption, we tested whether carteolol may affect BAT.(ABSTRACT TRUNCATED AT 250 WORDS)

Centrally induced vasopressor and sympathetic responses to a novel endogenous peptide, adrenomedullin, in anesthetized rats

Possible central actions of adrenomedullin were explored and compared with the peripheral effects by injecting it into the lateral ventricle, cisterna magna, and femoral vein in urethane-anesthetized rats. Adrenomedullin, 1.0 to 3.0 nmol/kg, injected intravenously (i.v.), caused a transient vasodepression of about 10 to 30 mm Hg, dose dependently, which lasted for < 15 min. On the other hand, intracerebroventricular (ICV) and intracisternal (IC) injections of adrenomedullin elicited sustained elevations of arterial pressure of gradual onset, dose dependently; the arterial pressure started to rise at about 3 min after the injection, and gained peak response after > 20 min. The pressor response lasted for > 2 h. Heart rate was not significantly influenced by these doses of adrenomedullin. The abdominal sympathetic outflow was markedly increased in relation to the blood pressure elevation. The time-course of the responses was quite similar with both ICV and IC injections. Hypotensive effects of i.v. injected adrenomedullin was partially attenuated, and the centrally induced vasopressor responses were abolished by the pretreatment with human calcitonin gene-related peptide (hCGRP)-receptor antagonist, hCGRP(8-37). These findings indicate that the receptors for adrenomedullin exist in the brain, and that the receptor site may be anatomically far from the surface of the brain and the ventricular system because the onset of the pressor response was delayed. Or, CGRP and adrenomedullin may share the same receptors, particularly in the brain.