Endothelial cell-binding antibodies in patients with systemic lupus erythematosus.

Abstract The implications of endothelial cell-binding IgG antibodies (EC IgG) in systemic lupus erythematosus (SLE) was evaluated by determining level of EC IgG in sera from 112 SLE patients. The serum EC IgG level was determined by the cyto-ELISA method using human umbilical vein endothelial cells (HUVEC), human microvascular endothelial cells (HMVEC), and aortic endothelial cells (HAEC) as antigens. The levels of EC IgG were significantly higher among patients with SLE than among healthy control subjects (P < 0.001), and 68% (76/112) of SLE patients were shown to be EC IgG-positive. In patients with active lupus nephritis, the level of EC IgG was statistically and significantly elevated compared with those without lupus nephritis (P < 0.05). Negative correlations between EC IgG level and levels of CH50, C3, and lymphocyte count were revealed (P < 0.05, P < 0.005, and P < 0.05, respectively). When clinical course was evaluated, the levels of EC IgG correlated with disease activity. Definitive correlations in antibody levels between HUVEC and HMVEC, and between HUVEC and HAEC were revealed (both P < 0.0001). The results of this study revealed that the EC IgG in patients with SLE was involved in the onset of clinical manifestation, especially in patients with active lupus nephritis.

In situ observation of superdislocation motion in pre-strained Ni3Ge single crystals.

Dislocation structures and their effect on the superdislocation motion in Ni3Ge single crystals have been studied by two-step deformation. In these tests either octahedral or cube slips were induced by prestraining. A difference in the induced dislocation structure is found to cause a notable change in the second deformation step depending on the combination of the stress axes. In order to understand the orientation sensitive hardening, in-situ deformation experiments have been made on the prestrained specimens in a high voltage electron microscope. Besides observation of the structural change due to dislocation motion, electron irradiation, which decorates antiphase boundary tubes, is utilized to trace the history of the rapid dislocation motion. Based on these observations, the origin of the anomalous strengthening in Ni3Ge is discussed with particular interest in the fine and non-planar dislocation structures induced by cross slips and dislocation-dislocation interactions.

Effect of immune complexes in serum from patients with rheumatoid vasculitis on the expression of cell adhesion molecules on polymorphonuclear cells.

OBJECTIVE: Immune complexes (IC) are frequently detected in patients with rheumatoid vasculitis (RV). To explore the pathogenic role of IC in the development of vasculitis among patients with rheumatoid arthritis (RA), we examined the effect of IC on the expression of cell adhesion molecules (CAM) on polymorphonuclear cells (PMN). METHODS: PMN from healthy volunteers were incubated with the sera from 26 patients with RA including 9 patients with RV, and the expression of CAM on the PMN was assessed by flow cytometry. RESULTS: We found that 67% (6/9) of the serum samples from RV patients and 18% (3/17) of the samples from RA patients without RV revealed up-regulated CD11b expression. On the other hand, 89% (8/9) of the samples from RV patients and 12% (2/17) of the samples from RA patients without RV revealed up-regulated CD18 expression. However, the expression of CD11a was not affected. Up-regulation of CD11b and CD18 on PMN was also induced by the immunoglobulin G (IgG) fraction of the sera of RV patients. Moreover, L-selectin expression on PMN was down-regulated by the sera or IgG of some patients with RV. These changes in CAM expression on PMN induced by IgG of RV patients were not observed when PMN were incubated with the IgG of RV patients from which the IC formed by IgG had been removed. CONCLUSION: These results suggest that IC formed by IgG in patients with RA are involved in the development of vasculitis by affecting the expression of CAM on PMN.

Soluble CD154 in rheumatoid arthritis: elevated plasma levels in cases with vasculitis.

OBJECTIVE: To determine the levels of soluble CD154 (sCD154) in the plasma of patients with rheumatoid arthritis (RA) and rheumatoid vasculitis (RV). and to examine the relationship between the levels of sCD154 in plasma and the clinical variables. METHODS: Levels of sCD154 were quantified in 39 plasma samples from patients with RA, including 9 patients who were also diagnosed with RV, and compared with those of 20 healthy subjects. An ELISA was established and specificity of the ELISA was tested by control ELISA using isotype-matched IgG and preabsorption assay. The titers of IgM and IgG rheumatoid factor (IgM-RF, IgG-RF) for each patient were determined simultaneously, and values of other laboratory variables were also determined. RESULTS: Levels of sCD 154 in plasma were higher in patients with RA than in the healthy subjects (p < 0.02). Compared with RA patients without vasculitis, patients with RV had significantly higher levels of sCD154 in their plasma (p < 0.001). Control ELISA and absorption assay of sCD154 indicated that our ELISA system was capable of measuring plasma sCD154 in RA patients. Levels of sCD154 in RA plasma correlated significantly with both IgM-RF and IgG-RF titers (r = 0.64 and 0.61, respectively, both p < 0.001). The levels of sCD154 decreased after commencement of treatment for vasculitis in cases with RV. CONCLUSION: We identified the presence of sCD154 in RA plasma, with especially high levels in cases with vasculitis. Correlation between sCD154 and RF titers indicates the CD154-CD40 pathway is likely related to pathogenic RF production.

Pentoxifylline induces the shedding of L-selectin on polymorphonuclear cells by stimulation via adenosine receptor as well as by the inhibition of phosphodiesterase.

Abstract We investigated the effects of pentoxifylline (PTX) on the expression of L-selectin on polymorphonuclear leukocytes (PMN). PTX induced the down-regulation of L-selectin expression in dose- and time-dependent manner. The measurement of soluble L-selectin in the culture medium by ELISA indicated that the down-regulation of L-selectin expression by PTX was due to the shedding of L-selectin from PMN. The mechanism by which PTX induced the shedding of L-selectin was investigated. The concentration of intracellular cyclic AMP (cAMP) was increased after treatment of PMN with PTX. However, an elevation of cAMP induced by dibutyryl cAMP (dbcAMP) as well as other methylxanthine derivatives (caffeine, aminophylline, and theophylline) did not induce the shedding of L-selectin. Although stimulation of the adenosine receptor with 5'-N-ethylcarboxamidoadenosine (NECA) or 5'-(N-cyclopropyl)-carboxamido-adenosine (CPCA) adenosine receptor agonists did not induce the shedding of L-selectin, shedding of L-selectin was demonstrated when PMN was incubated simultaneously with rolipram, a phosphodiesterase (PDE) inhibitor, and CPCA. Moreover, shedding of L-selectin induced by PTX was attenuated by aminophylline, an adenosine receptor antagonist. These results indicated that PTX induces the shedding of L-selectin on PMN by stimulation via the adenosine receptor as well as inhibition of PDE.

Cholangiolocellular carcinoma of the liver: CT and MR findings.

The authors report two cases of surgically proved cholangiolocellular carcinoma of the liver. Marked contrast enhancement was observed at the periphery of the tumor on CTs and MRIs obtained during the hepatic arterial and portal venous phases, with concentric filling on the delayed images. On T1-weighted and T2-weighted MRIs, the tumor was, respectively, hypointense and hyperintense, with a central hypointense area. Therefore, helical CT and MRI features of these cholangiolocellular carcinomas were thought to be similar to those of cholangiocarcinoma.

Fas ligand-mediated exocrinopathy resembling Sjögren's syndrome in mice transgenic for IL-10.

Although IL-10 has been implicated in the pathogenesis of several autoimmune diseases, the mechanisms by which this cytokine mediates inflammatory lesions remain to be elucidated. Exocrine gland destruction is an important early step in the development of Sjögren's syndrome. To better understand the role of IL-10 in Sjögren's syndrome, we made transgenic mice in which the mouse IL-10 gene was regulated by the human salivary amylase promoter. Transgenic expression of IL-10 induced apoptosis of glandular tissue destruction and lymphocyte infiltration consisting primarily of Fas-ligand (FasL)+ CD4+ T cells, as well as in vitro up-regulation of FasL expression on T cells. These data suggest that overexpression of IL-10 in the glands and their subsequent Fas/FasL-mediated bystander tissue destruction is a causal factor in the development of this disease.

Isolation and mapping of a polymorphic CA repeat sequence at the human interleukin 6 locus.

A polymorphic dinucleotide (CA) sequence was isolated from a genomic clone containing the human interleukin 6 (interferon beta-2) gene and was mapped to 7p21. This polymorphism will be useful in the genetic study of disorders affecting the inflammation process, calcium metabolism, and hematologic malignancies.

Monoclonal anti-cardiolipin antibodies from New Zealand Black x New Zealand White F1 mice react to thrombomodulin.

The reactivity with and affinity for thrombomodulin (TM) of monoclonal anti-cardiolipin Abs (MoaCL), derived from a New Zealand Black x New Zealand White F1 (NZB/W F1) mouse, were studied to investigate the pathogenicity of anti-cardiolipin Abs (aCL). Four of eighteen MoaCL were found to react with rabbit TM when examined using ELISA. These four MoaCL also reacted with synthetic peptide that included the epidermal growth factor-like domain of human TM, a binding site for thrombin. The reaction with TM of these four MoaCL was inhibited by bovine thrombin. When the affinity for TM of the MoaCL was determined, the dissociation constants (Kd) ranged from 4.8 x 10(-9) to 4.7 x 10(-8) M. By contrast, examination of the affinity for cardiolipin (CL) gave values from 8.3 x 10(-6) to 7.4 x 10(-5) M. Thus, these MoaCL reacted to TM with a higher affinity than to CL. Moreover, these MoaCL also bound to TM on HUVEC and down-regulated the expression level of TM on the surface of HUVEC due to internalization of TM. The binding of thrombin to TM is known to initiate rapid protein C activation, and complexes of activated protein C and protein S show anticoagulatory activity. Thus, the present studies suggest that certain pathogenic aCL cross-react with TM and induce down-regulation of TM on endothelial cells, followed by induction of thrombosis.

K+ channel-opening action contributes to the preventive effects of nicorandil on U46619-induced vasoconstriction of canine large coronary arteries in vivo.

The antispasmogenic effects of nicorandil on epicardial coronary artery vasoconstriction were compared with those of a K+ channel opener, cromakalim, and a nitrovasodilator, nitroglycerin, in open-chest dogs. Intracoronary administration of U46619 (0.5-1.0 micrograms), a stable thromboxane A2 analogue, reduced the external diameter of the left circumflex coronary artery with no marked alternations in systemic hemodynamics. This U46619-induced vasoconstriction of large epicardial coronary arteries was dose-dependently prevented by the intracoronary infusion of nicorandil (1-10 micrograms/kg/min), cromakalim (0.03 micrograms/kg/min) and nitroglycerin (1 micrograms/kg/min). After pretreatment with glibenclamide (3 mg/kg, i.v.), and ATP-sensitive K+ channel blocker, these effects of nicorandil and cromakalim were inhibited significantly, whereas the response to nitroglycerin remained unchanged. Nicorandil (3 micrograms/kg/min), cromakalim (0.03 micrograms/kg/min) and nitroglycerin (1 micrograms/kg/min) increased coronary blood flow. However, the inhibitory effects of each drug on the U46619-induced vasoconstriction were not influenced by the partial occlusion of the left circumflex coronary artery, which kept coronary blood flow constant. This indicates a direct antispasmogenic effect of K+ channel openers, which is independent of that mediated by the response to flow. Furthermore, our results suggest that, by this effect, nicorandil protects large coronary arteries from U46619-induced vasoconstriction.

Flush induced by fluoroquinolones in canine skin.

The flush induced by two fluoroquinolone antibacterial agents, balofloxacin and ofloxacin, was studied in beagle dogs. Intradermal injection of the fluoroquinolones at concentrations above 10(-5) M produced a localized flushed area. The flush responses to fluoroquinolones were inhibited by co-administration with H2-antagonist(s) (ranitidine or cimetidine), but not with H1-antagonist(s) (mepyramine or chlorpheniramine). Similar inhibitory effects of these H2-antagonists were observed for the response to histamine. The flush responses to fluoroquinolones were inhibited by a local pretreatment with compound 48/80 administered to deplete the local stores of mast cell-bound histamine. When the fluoroquinolones were orally administered at a dose of 400 mg/kg, the concentration of histamine in plasma was increased, being accompanied by systemic erythema. These results indicate that the flush induced by fluoroquinolones is mediated by histamine release from canine cutaneous mast cells and H2-receptor stimulation.

A comparative study of whole-blood platelet aggregation in laboratory animals: its species differences and comparison with turbidimetric method.

We undertook a systematic comparison of whole-blood platelet aggregation concerning species difference of commonly used laboratory animals (rabbits, guinea pigs, rats and dogs), agonist difference (collagen, ADP and platelet activating factor [PAF] and technical difference against a traditional method of turbidimetry. Collagen-induced aggregation with whole-blood aggregometry was less variable among species tested and was similar to the results obtained by turbidimetry, which measures platelet aggregation in citrated plasma. In contrast, whole-blood aggregometry in responses to ADP and PAF showed marked species difference, being different from turbidimetry. Our results provide species difference among laboratory animals and suggest that the modulations of platelet aggregation by other blood elements probably differ in each species and with stimulating agonists.

Pressor response induced by the hippocampal administration of neostigmine is suppressed by M1 muscarinic antagonist.

We investigated the roles played by three muscarinic receptors (M1, M2, and M3) in the pressor response with bradycardia that followed the injection of neostigmine (5 x 10(-8) mol) into the hippocampus of anesthetized rats. These changes were blocked by the co-administration of methylatropine (5 x 10(-8) mol). The intrahippocampal injection of pirenzepine (M1 antagonist) (5 x 10(-9) - 5 x 10(-7) mol) suppressed the neostigmine-induced pressor response dose-dependently. However injection of gallamine (M2 antagonist) (5 x 10(-8) - 5 x 10(-7) mol) and of 4-DAMP (M1 and M3 antagonist) (5 x 10(-8) - 5 x 10(-7) mol) did not suppress this hypertensive response. These findings suggest that the neostigmine-induced pressor response with bradycardia is mediated through the M1 muscarinic receptor subtype.

Effects of ginsenosides on impaired performance induced in the rat by scopolamine in a radial-arm maze.

The effects of ginsenosides Rg1, Rd and Rb1 on impaired performance induced in the rat by scopolamine were examined in a radial-arm maze. Scopolamine caused a reduction in the number of initial correct responses in the maze. A single IP injection of Rg1, but not Rd or Rb1, prevented the reduction. The inhibition of the reduction in initial correct responses was associated with a bell-shaped dose-response curve for Rg1. A lesion in the medial septum caused spatial learning deficits. Rg1 did not overcome these deficits. It is suggested that cholinergic neurons in the medial septum are involved in the ameliorative effect of Rg1 on impaired performance induced by scopolamine.

Gastrointestinal motor inhibition by exogenous human, salmon, and eel calcitonin in conscious dogs.

Effects of synthetic eel (E-), salmon (S-), and human (H-) calcitonin (CT) on gastrointestinal motility were studied in conscious beagle dogs, which had been implanted with strain gauge force transducers. Intramuscular administration of E-, S-, or H-CT interrupted gastric migrating motor complexes, digestive pattern, and gastric emptying. The order of potency was E-CT = S-CT > H-CT. Motor inhibition induced by CT occurred independently of plasma immunoreactive motilin levels or hypocalcemia. In addition, E-CT and S-CT induced vomiting without a retrograde giant contraction (RGC) during the postprandial state. Apomorphine or CuSO4 initiated RGC prior to vomiting. RGC induced by apomorphine was inhibited by pretreatment with E-CT as well as hexamethonium, atropine, or surgical vagotomy. E-CT showed no inhibitory effect on nicotine stimulated contraction of isolated guinea-pig ileum. These results suggest that peripherally administered CT inhibits canine gastrointestinal motility at the central nervous system level by lowering vagal activity.

Effects of ionic and nonionic contrast media on cardiohemodynamics and quality of radiographic image during canine angiography.

Cardiovascular responses and radiographic image quality during cerebral angiography, aortofemoral angiography and left ventriculography with nonionic ioxilan, iohexol or iopamidol were compared with those of ionic sodium meglumine diatrizoate in pentobarbital anesthetized dogs. Injection of all contrast media caused cardiovascular changes to a greater or lesser degree, e.g., hypotension, bradycardia, tachycardia, a decrease in left ventricular pressure (LVP) and its first derivative (dP/dt), and prolongation of the P-Q and Q-T intervals. Ionic diatrizoate had a greater effect on cardiovascular parameters than nonionic contrast media during angiography in all areas. Moreover, diatrizoate produced cardiac arrhythmias and prominent changes in blood rheology concerned with blood viscosity and deformability of the erythrocyte. The cause of various effects of contrast media seemed to lie mainly in osmolality, viscosity and partially ionic additives. The radiographic image quality of all of the contrast media used was similar, but nonionic ioxilan and iohexol with lower iodine content and low osmolality gave better radio opacity than ionic diatrizoate in cerebral angiography. These results suggested that nonionic contrast media should be recommended as a diagnostic tool for both animals and human patients in poor health.

Postprandial change in canine blood viscosity.

1. Postprandial variation in blood viscosity was studied in beagle dogs. 2. Blood viscosity increased following feeding. This change was caused by haematocrit elevation, which resulted mainly from splenic contraction. 3. Haemoconcentration, plasma viscosity and erythrocyte deformability did not contribute to the postprandial increment in blood viscosity.