Functional folate receptor beta-expressing macrophages in osteoarthritis synovium and their M1/M2 expression profiles.

OBJECTIVE: The distribution of folate receptor (FR)-ß+ macrophages and their M1/M2 expression profiles were examined in osteoarthritis (OA) synovial tissues, and compared to those in rheumatoid arthritis (RA) synovial tissues and CD163+ macrophages in both OA and RA synovial tissues. METHOD: The phenotypes and fluorescein isothiocyanate (FITC)-folate uptake of FR-ß+ synovial macrophages were analysed by flow cytometry. The distribution of FR-ß+ macrophages in OA and RA synovial tissues was examined by immunofluorescent microscopy. Tumour necrosis factor (TNF)-α, inducible nitric oxide synthase (iNOS), interleukin (IL)-10, and transforming growth factor (TGF)-ß expression in FR-ß+ macrophages was detected by double-immunostaining in both OA and RA synovial tissues. RESULTS: FR-ß+ macrophages were predominantly present in the synovial lining layer in OA patients. The proportion of CD163-FR-ß+ cells in synovial mononuclear cells (MNCs) was increased in OA compared to RA synovial tissues. FR-ß(high) macrophages from OA synovial tissues represented the majority of folic acid-binding cells. Although FR-ß+ or CD163+ macrophages in the synovial tissues of OA and RA patients expressed a mixed pattern of M1 and M2 macrophage markers, there were more M2 markers expressing synovial macrophages in OA than in RA patients. CONCLUSIONS: The distribution and M1/M2 expression profiles of FR-ß+ synovial macrophages were different between OA and RA synovial tissues. Thus, the findings underscore that the M1/M2 paradigm using surface markers FR-ß and CD163 is an oversimplification of macrophage subsets. Functional FR-ß present on OA synovial macrophages provides a potential tool for the diagnosis and treatment of OA.

Expansion of a unique macrophage subset in rheumatoid arthritis synovial lining layer.

The Z39Ig protein (complement receptor for C3b and iC3b) is expressed on resident tissue macrophages in various tissues. This study was undertaken to examine the distribution of Z39Ig+cells and their phenotypic features in rheumatoid arthritis (RA) synovium, in comparison with those of osteoarthritis (OA) and psoriatic arthritis (PsA) synovium. Monoclonal anti-Z39Ig antibody was produced by immunizing Z39Ig transfected murine pre B cells and used for the identification of Z39Ig+cells. Z39Ig+cells were further stained with antibodies to macrophages, fibroblast-like synoviocytes, complement receptors and dendritic cells by using the double immunostaining method in normal, RA, OA and PsA synovium. RA synovial mononuclear cells were double-stained using anti-Z39Ig and anti-CD11c antibodies and sorted into Z39Ig+CD11c+cells and Z39Ig+CD11c-cells. These cell populations were then analysed by electron microscopy. The expression of the Z39Ig protein was limited to intimal macrophages in normal, RA, OA and PsA synovium. The numbers of Z39Ig+CD11c+cells and the ratios of Z39Ig+CD11c+cells to Z39Ig+cells were increased in the synovial lining layer of RA as compared with those of OA and PsA. The ultrastructural analysis of Z39Ig+CD11c+cells showed the character of macrophages with many secondary lysosomes and swelling of mitochondria. Z39Ig+ cells appeared to be useful for identification of resident tissue macrophages in normal synovium and the corresponding macrophages in the synovial lining layer of inflammatory arthritis. Expansion of Z39Ig+CD11c+cells was characteristic of RA synovial lining layer.

Establishment of enzyme immunoassay for measuring serum sultopride levels.

Measurement of serum sultopride levels was performed using an enzyme immunoassay. Little or no cross-reactivity with metabolites of sultopride and other drugs was found. The results of reproducibility, recovery, and dilution testing were all good enough for clinical use. A comparison between the measurement values of this method (y) with that of high-performance liquid chromatography (x) showed high correlation (n = 211, r = 0.991, p < 0.0001, y = 0.99x + 107.5). In a comparison between the sultopride dose and serum levels in 161 patients, interindividual differences were large (19 times for same doses), implying that the serum level cannot be predicted from the dosage. The method was found to be reliable for serum level measurements of sultopride and useful for monitoring compliance and assessing the optimal dose.

CYP2D6*10 alleles are not the determinant of the plasma haloperidol concentrations in Asian patients.

The authors we investigated the relationship between plasma levels of haloperidol (HAL) and the number of CYP2D6*10 (*10) alleles in 66 Japanese inpatients with schizophrenia (male = 61, female = 5) on HAL. Plasma HAL level was determined by an enzyme immunoassay method. Daily dose of HAL was 1.5-36 (mean +/- SD = 12.3 +/- 7.6) mg or 0.02-0.49 (0.21 +/- 0.13) mg/kg body weight. Plasma HAL levels ranged from 1.4 to 47.4 (12.4 +/- 9.5) ng/mL. No significant difference in the plasma HAL levels was observed between the subjects with no, one, and two *10 alleles (one-way analysis of variance: 56.1 +/- 20.3, 61.0 +/- 20.3, and 63.3 +/- 20.3 ng/mL/mg/kg, respectively, F(2,63) = 0.65, p = 0.52). These results are not supportive of the previous report that plasma HAL levels can be predicted by the number of *10 alleles in Asian patients.

Human heart-type cytoplasmic fatty acid-binding protein (H-FABP) for the diagnosis of acute myocardial infarction. Clinical evaluation of H-FABP in comparison with myoglobin and creatine kinase isoenzyme MB.

Heart-type fatty acid-binding protein (H-FABP) is a low molecular weight cytoplasmic protein and present abundantly in the myocardium. When the myocardium is injured, as in the case of myocardial infarction, low molecular weight cytoplasmic proteins including H-FABP are released into the circulation and H-FABP is detectable in a blood sample. We have already developed a direct sandwich-ELISA for quantification of human H-FABP using two distinct types of monoclonal antibodies specific for human H-FABP. In this study we investigated the clinical validity of H-FABP as a biochemical diagnostic marker in the early phase of acute myocardial infarction (AMI). To evaluate the diagnostic usefulness of H-FABP in the early phase of AMI, blood samples were obtained from the following patients within 12 hours after the appearance of symptoms, and serum levels of H-FABP were compared with those of conventional diagnostic markers, such as myoglobin and creatine kinase isoenzyme MB (CK-MB). Blood samples were collected from patients with confirmed AMI (n=140), patients with chest pain who were afterwards not classified as AMI by normal CK-MB levels (non-AMI) (n=49) and normal healthy volunteers (n=75). The serum concentration of H-FABP was quantified with our direct sandwich-ELISA. The concentration of myoglobin mass was measured with a commercial RIA kit. The serum CK-MB activity was determined with an immuno-inhibition assay kit. The overall sensitivity of H-FABP, within 12 hours after the appearance of symptoms, was 92.9%, while it was 88.6% with myoglobin and 18.6% with CK-MB. The overall specificity of H-FABP was 67.3%, while it was 57.1% with myoglobin and 98.0% with CK-MB. The diagnostic efficacy rates with these markers were 86.2% (H-FABP), 80.4% (myoglobin) and 39.2% (CK-MB), respectively. The diagnostic validity of H-FABP was further assessed by receiver operating characteristic (ROC) curve analysis. The area under the curve (AUC) of H-FABP was 0.921, which was significantly greater than with myoglobin (AUC: 0.843) and CK-MB (AUC: 0.654). These parameters, such as sensitivity, specificity, diagnostic efficacy and diagnostic accuracy, obtained for patients with chest pain within 3 hours and/or 6 hours after the onset of symptoms were almost the same as those for patients within 12 hours after symptoms. H-FABP is more sensitive than both myoglobin and CK-MB, more specific than myoglobin for detecting AMI within 12 hours after the onset of symptoms, and shows the highest values for both diagnostic efficacy and ROC curve analysis. Thus, H-FABP has great potential as an excellent biochemical cardiac marker for the diagnosis of AMI in the early phase.

Development and evaluation of a direct sandwich-enzyme-linked immunosorbent assay for the quantification of human hepatic triglyceride lipase mass in human plasma.

We have developed a direct sandwich-enzyme-linked immunosorbent assay (ELISA) for quantification of the hepatic triglyceride lipase (HTGL) immunoreactive mass in human plasma. This direct sandwich-ELISA uses a combination of two distinct monoclonal antibodies (MAbs), which recognize different epitopes on the HTGL molecule: a horseradish peroxidase (HRP)-labeled anti-human HTGL MAb (2(4)F12C12) as an enzyme-linked MAb, and an anti-human HTGL MAb (1(11)A3H3) coated on a microtiter plate as a solid-phase MAb. Purified human post-heparin plasma (PHP)-HTGL was used as the standard material. The detection range of the sandwich-ELISA was 40-800 ng of HTGL protein per ml of plasma. The intra- and inter-assay coefficients of variation were less than 2.0% and 2.3%, respectively. The recovery tests resulted in variation only between 97.7% and 103.5%. No significant assay interference was caused by a high concentration of triglyceride, hemoglobin, bilirubin, uric acid, or creatinine. The reliability of the HTGL mass values obtained with the direct sandwich-ELISA was assessed by comparison with the HTGL mass values determined by our earlier one-step sandwich-enzyme immunoassay (EIA). The two sets of values showed a highly significant correlation (r=+0.952, n=64). Strong correlation (r=+0. 959, n=50) was also found between the HTGL masses with the direct sandwich-ELISA and the HTGL activities determined with a selective immunoinactivation assay. The HTGL mass concentrations in PHP from 64 healthy subjects were 1916+/-841 ng/ml by the direct sandwich-ELISA and 1925+/-785 ng/ml (mean+/-standard deviation (SD)) by the one-step sandwich-EIA. The present direct sandwich-ELISA permits rapid identification of certain HTGL abnormalities in PHP samples from patients with hypertriglyceridemia or diseases such as hypothyroidism or renal failure, which affect HTGL.

Selective expression of folate receptor beta and its possible role in methotrexate transport in synovial macrophages from patients with rheumatoid arthritis.

OBJECTIVE: To investigate the expression of folate receptors (FR) and reduced folate carrier (RFC) and determine their relevance to methotrexate (MTX) transport in synovial mononuclear cells (SMC) from patients with rheumatoid arthritis (RA). METHODS: Levels of FR and RFC messenger RNA (mRNA) were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) in SMC from RA patients and peripheral blood mononuclear cells from healthy donors. Expression of FR-beta mRNA and protein was determined by Northern blot and Western blot analyses in RA SMC and monocyte/macrophage-lineage cells. FR-beta expression and folic acid binding capacity on the cell surface were examined by flow cytometric analysis and 3H-folic acid binding analysis. Studies of the inhibition of 3H-MTX uptake in the presence of unlabeled folic acid were performed to investigate the uptake of MTX through FR in RA SMC. RESULTS: RT-PCR, Northern blot, and Western blot analyses showed that FR-beta mRNA and protein were expressed selectively in activated monocytes and CD14+ RA SMC. These cells exhibited folic acid binding capacity. Furthermore, the FR-beta protein was shown to have folic acid binding capacity. Uptake of 3H-MTX through RA SMC was significantly inhibited in the presence of unlabeled folic acid. CONCLUSION: These results demonstrate that FR-beta expression is selectively elevated in RA synovial macrophages and suggest that MTX is transported through FR-beta in RA synovial macrophages. The findings suggest that folate antagonists with higher affinity for FR-beta would be useful in the treatment of RA.

Development and evaluation of a direct sandwich enzyme-linked immunosorbent assay for the quantification of lipoprotein lipase mass in human plasma.

OBJECTIVE: The purpose of this study was to develop and evaluate a direct sandwich enzyme-linked immunosorbent assay (ELISA) for quantification of the lipoprotein lipase (LPL) immunoreactive mass in human plasma using monoclonal antibodies (MAbs) directed against LPL purified from human postheparin plasma (PHP) [corrected]. METHODS AND RESULTS: The direct sandwich-ELISA was performed using a combination of two distinct types of MAbs that recognize different epitopes on the LPL molecule. The immunoreactive mass of human LPL was specifically measured using a horseradish peroxidase-labeled anti-human LPL MAb [1(1)D2B2] as an enzyme-linked MAb, and an anti-human LPL MAb [2(10)F8F9] coated on a polystyrene microtiter plate as a solid-phase MAb. Purified human PHP-LPL was used as a standard material. The detection range of the sandwich-ELISA was 3.6-460 ng of LPL protein per mL of plasma. The intra- and interassay coefficients of variation were less than 5.9% and 3.3%, respectively. The validity of this method was additionally assured by the recovery test, which resulted in the variation only between 97.5% and 105.1%, and also by the interference test, which resulted in noninterference of LPL assay with a high concentration of triglyceride, hemoglobin, bilirubin, uric acid, or creatinine. To assess the reliability of the LPL mass values obtained with the direct sandwich-ELISA, they were compared with LPL mass values determined by the one-step sandwich-EIA (MARKIT-F LPL EIA kit) previously established by us. This comparison showed a highly significant correlation (r = +0.990) between the two sets of values. The LPL mass concentrations in PHP from 33 healthy subjects were 267 +/- 53 and 257 +/- 59 ng/mL (mean +/- SD), respectively. CONCLUSION: The present direct sandwich-ELISA is useful for rapidly identifying certain abnormalities of LPL in PHP samples from patients with hypertriglyceridemia [corrected].

3- to 11-year followup of occipitocervical fusion for rheumatoid arthritis.

The relief of myelopathy usually is unsatisfactory by a conventional Gallie type atlantoaxial fusion for patients with rheumatoid arthritis who have irreducible atlantoaxial dislocation. To accomplish a decompressive laminectomy of the atlas in the treatment of myelopathy, the authors have been performing a new surgical procedure since 1985 for occipitocervical fusion using a rectangular rod. The postoperative outcomes for 25 patients with rheumatoid arthritis were evaluated clinically and radiographically with a 3- to 11-year (mean, 6.5 years) followup. A decompressive laminectomy of the atlas accompanied the fusion in 21 of the 25 patients. The incidence of occipital or nuchal pains improved notably in most cases, and myelopathy was relieved in 12 of 18 (67%) cases, showing an improvement of more than one level based on Ranawat's criteria. No serious postoperative complications were seen, except for one case of a failed bone union. The cumulative survival in patients with myelopathy was 79.4% in the first 5 years after operation and 27.5% at 10 years. Occipitocervical fusion using a rectangular rod accompanied by a decompressive laminectomy of the atlas can contribute to the relief of a neurologic deficit in an irreducible atlantoaxial dislocation in rheumatoid arthritis.

Pathological significance of elevated soluble CD14 production in rheumatoid arthritis: in the presence of soluble CD14, lipopolysaccharides at low concentrations activate RA synovial fibroblasts.

In order to establish what contributes to elevated levels of soluble CD14 (sCD14) in rheumatoid arthritis (RA) plasma, levels of sCD14 were compared in RA-paired plasma and synovial fluids and, further, in the culture supernatants of monocyte-rich fractions from patients with RA and healthy donors, and macrophage-rich fractions from RA synovial tissues. The results showed elevated sCD14 in RA synovial fluid in 9 of 16 paired samples and in RA macrophage-rich fractions, suggesting that elevated sCD14 in RA plasma might be due to the sCD14 production by RA synovial macrophages. From the molecular analysis of elevated sCD14, the proteolytic cleavage of membranous CD14 (mCD14) was important in accelerated sCD14 production. Lipopolysaccharides (LPS) at low concentrations and sCD14 increased the ICAM-1 expression on RA synovial fibroblasts. This result implies that in vivo RA synovial fibroblasts may be sensitive to LPS in the presence of sCD14 and LPS-binding protein (LBP).

Clinical course of conservatively managed rheumatoid arthritis patients with myelopathy.

STUDY DESIGN: The clinical course of rheumatoid arthritis patients with myelopathy who do not undergo surgery was studied. OBJECTIVES: To establish a more accurate prognosis for rheumatoid arthritis patients who do not undergo surgery. SUMMARY OF BACKGROUND DATA: Cervical myelopathy has been reported in two thirds of rheumatoid arthritis patients with atlantoaxial dislocation. Atlantoaxial fusion, or occipitocervical fusion, is widely performed on these patients. However, several researchers reported serious complications from the surgery, including nonunion, worsening myelopathy, and high mortality. The natural course of disease in rheumatoid arthritis patients with myelopathy should be known before definitive treatments can be outlined. MATERIALS AND METHODS: Twenty-one rheumatoid arthritis patients with myelopathy resulting from atlantoaxial dislocation were studied. Fourteen of the 21 cases were associated with upward migration of the odontoid process. All of these patients were recommended for surgery, but they refused. Patients were reviewed by direct examination yearly. Radiographic changes and clinical course, including the survival rate, were observed. RESULTS: Atlantodental interval and Redlund-Johnell measurements deteriorated. The patients showed no neural improvement, and deterioration was found in 16 (76%) cases during follow-up. All patients became bedridden within 3 years of the onset of myelopathy. Seven of the 21 patients died suddenly for unknown reasons, 3 died of pneumonia, and 1 died of multiple organ failure. The three sudden-death cases showed progressive upward migration of the odontoid process. The cumulative probability of survival was 0% in the first 7 years after the onset of myelopathy. CONCLUSIONS: The clinical results for rheumatoid arthritis patients with myelopathy treated without surgery are extremely poor. Surgical treatment is recommended for rheumatoid arthritis patients with myelopathy.

Biomechanical analysis of buckling alignment of the cervical spine. Predictive value for subaxial subluxation after occipitocervical fusion.

STUDY DESIGN: A biomechanical analysis of the buckling type of alignment on nonfused cervical segments was carried out in patients with occipitocervical fusion for atlantoaxial dislocation. OBJECTIVES: To examine whether biomechanical analysis is useful for preoperative prediction of subaxial subluxation after occipitocervical fusion. SUMMARY OF BACKGROUND DATA: Rheumatoid arthritis sometimes causes subaxial subluxation after occipitocervical fusion. At present, there are no widely accepted criteria for determining the appropriate extent of fusion to prevent subluxation. METHODS: The subjects were 25 patients with rheumatoid atlantoaxial dislocation and 15 patients with nonrheumatoid atlantoaxial dislocation who underwent occipitocervical fusion. Preoperative and postoperative alignment of the cervical spine were analyzed biomechanically, using a specially developed computer program. RESULTS: Five segments of nonfused cervical spine had subluxation after surgery in the rheumatoid group. For these segments, the preoperative value of buckling averaged 13.5 x 10(-4) and exceeded 10 x 10(-4) in all cases. For the segments that showed no subluxation after surgery, the preoperative value of buckling averaged 4.5 x 10(-4). Subluxation of the nonfused segments did not develop in the nonrheumatoid group. CONCLUSIONS: In patients with rheumatoid arthritis, segments that show abnormal buckling before surgery are likely to develop subluxation after occipitocervical fusion. Preoperative values of buckling over 10 x 10(-4) constitute a risk factor for subaxial subluxation after occipitocervical fusion.

Determination of bradykinin-(1-5) in inflammatory exudate by a new ELISA as a reliable indicator of bradykinin generation.

We have developed an ELISA for BK-(1-5) (Arg1-Pro2-Pro3-Gly4-Phe5). In rat carrageenin-induced pleurisy, in which a plasma exudation peak was observed 5 h after carrageenin, BK levels in the exudates were negligible (< 60 pg/rat). BK-(1-7) (des-Phe8-Arg9-BK) was detectable (900-400 pg/rat) over the entire course of the inflammation. However, a larger amount of BK-(1-5) was detectable in association with the increase in plasma exudation, showing a peak (8800 +/- 1200 pg/rat) 3 h after carrageenin. Bromelain (10 mg/kg, i.v.) and soy bean trypsin inhibitor (0.3 mg/rat, intra-pleural) significantly reduced BK-(1-5) levels (by 60-93%, 3, 7 and 19 h after carrageenin) and plasma exudation rates (by 61-74%, 3 and 7 h after carrageenin). Dexamethasone (0.3 mg/kg, i.p.) reduced BK-(1-5) levels (by 78%) and decreased plasma exudation (by 70%) 3 h after carrageenin. In nasal allergy patients, antigen challenge of nasal mucosa elevated BK-(1-5) levels and active kallikrein levels in nasal washes. These results verify that BK-(1-5) determined by ELISA is a good indicator for release of kinins in vivo.

Lack of contribution of circulatory kinin elevated by captopril to induce hypotension in normotensive and hypertensive rats.

Captopril (10 mg/kg, i.p.) increased the arterial bradykinin (BK) level (Art-BK) of non-treated Sprague-Dawley rats (SD), determined by an ELISA, from 10.8 +/- 3.2 pg/ml to 32.9 +/- 5.4 pg/ml significantly (p < 0.05, n = 6). Intravenous infusion of BK (100-3000 ng/kg/min) dose-dependently increased heart rate (HR) and decreased mean blood pressure (MBP), the former at lower doses than the latter, and the hypotensive response became significant at 3000 ng/kg/min. Art-BK determined during infusion of the lowest dose of BK (100 ng/kg/min) was 12 times the endogenous Art-BK after captopril administration. In spontaneously hypertensive rats, Wistar Kyoto rats, and deoxycorticosterone acetate-salt treated hypertensive rats, Art-BK (450-1280 pg/ml) determined during intravenous BK-infusion (1000-3000 ng/kg/min), which induced significant hypotension, was 20 to 100 times the endogenous Art-BK (4.5-64 pg/ml) with captopril treatment. These results suggest that the increased Art-BK due to inhibition of kinin degradation by captopril could not account for the hypotension due to this angiotensin converting enzyme inhibitor in normotensive and hypertensive rats.

Development of a sandwich enzyme-linked immunosorbent assay for the determination of human heart type fatty acid-binding protein in plasma and urine by using two different monoclonal antibodies specific for human heart fatty acid-binding protein.

We have developed a sandwich enzyme-linked immunosorbent assay (ELISA) for the determination of human heart type fatty acid-binding protein (H-FABP) in human plasma and urine using the combination of two distinct monoclonal antibodies (MAbs) directed against human H-FABP purified from human heart muscle. The total assay time of the ELISA is practically much shorter than that of the competitive enzyme immunoassay (EIA) we previously reported. The immunoreactive mass of human H-FABP was specifically measured using a horseradish peroxidase (HRPO)-labeled anti-human H-FABP MAb as an enzyme-linked MAb, and anti-human H-FABP MAb immobilized on the polystyrene microtiter plate as a solid-phase MAb, and purified human H-FABP as standard materials. The assay range of the ELISA was 0-250 ng/ml of plasma and urine. The ELISA yielded a coefficient of variation of less than 10% in inter- and intra-assays, and the good linearity was obtained in dilution test using clinical samples. Anticoagulants, except sodium fluoride and a high concentration of hemoglobin and bilirubin, did not interfere with the assay of plasma samples. A high concentration of hemoglobin, bilirubin and immunoglobulin, and contamination with seminal plasma did not interfere with the assay of urine samples. The average recovery of purified human H-FABP added to human plasma and urine samples was 98.5% and 97.0%, respectively. Myoglobin and myosin did not crossreact in the ELISA. The minimum detection limit of the ELISA was 1.25 ng/ml. The immunoreactive masses of human H-FABP in plasma and urine samples, obtained from one hundred normal healthy subjects were quantified by the sandwich ELISA. The normal mean (+/- SD) level of human H-FABP mass in plasma was 3.65 +/- 1.81 ng/ml, and that in urine was 3.20 +/- 2.70 ng/ml. In conclusion, this sandwich ELISA is a useful tool for the sensitive and precise determination of human H-FABP in human plasma and urine, and it may be used specifically for clinical investigation and diagnosis of myocardial injury.

Detection of the degradation products of bradykinin by enzyme immunoassays as markers for the release of kinin in vivo.

We developed an enzyme immunoassay (EIA) specific for Arg1-Pro2-Pro3-Gly4-Phe5 ([1-5]-BK) for determination of the levels of this peptide in biological fluids. Previously developed EIAs for bradykinin (BK) and for des-Phe8-Arg9-BK ([1-7]BK) were also used. Incubation of rat plasma with glass powder resulted in the transient appearance of BK. A degradation product, [1-7]BK, could be detected in the incubation mixture for a longer period of time. When compared with BK and [1-7]BK, a larger amount of [1-5]BK was detectable even longer. In carrageenan-induced pleurisy in rats, which was associated with a peak rate of plasma exudation 5 hr after administration of carrageenan, BK was undetectable (< 160 pg/rat) in the pleural exudates. By contrast, [1-7]BK was detectable over the entire course of the inflammatory response. A larger amount of [1-5]BK was detectable. The peak level of [1-5]BK was 6050 +/- 1050 pg/rat, 5 hr after administration of carrageenan. Inhibition of the generation of BK by intrapleural administration of soy bean trypsin inhibitor (0.3 mg/rat) 30 min before collection of pleural fluid resulted in significant reductions in the levels of both [1-7]BK (by 51-65%) and [1-5]BK (by 63-79%) in the exudates 3, 7 and 19 hr after administration of carrageenan. Intraperitoneal administration of captopril (10 mg/kg) caused a marked reduction (by 98%) in levels of [1-5]BK in exudates 3 hr after administration of carrageenan. The reduction was accompanied by an increase in the level of BK up to 1250% of that in untreated rats. These results indicate that the newly developed EIA for [1-5]BK might be a useful tool for verifying the release of kinin in vivo.

Increased secretion of glandular-kallikrein in the bronchial washings induced by intravenous injection of leukotriene C4 in guinea-pigs.

1. Intravenous administration of leukotriene C4 (LTC4) and LTD4 (1-10 nmol kg-1) caused a dose-dependent increase in secretion of glandular-kallikrein in the bronchial washings of guinea-pigs, as measured by cleavage of a synthetic substrate and the formation of kinin. LTC4 was more potent than LTD4 and pilocarpine was much less potent than peptide leukotrienes on a molecular basis. 2. The increases in levels of glandular-kallikrein in the bronchial washings that were induced by LTC4 (3 nmol kg-1, i.v.) were almost completely inhibited by pretreatment with an antagonist of leukotrienes (ONO-1078), with an antagonist of thromboxane (S-1452), with an inhibitor of thromboxane synthetase (OKY-046), with indomethacin, with atropine or with scopolamine. These results indicate that the LTC4-induced increase in levels of glandular-kallikrein may have been mediated by the formation of thromboxane and the release of acetylcholine. 3. The increases in levels of glandular-kallikrein in the bronchial washings induced by STA2 (20 pmol kg-1, i.v.), a stable analogue of thromboxane A2, were completely blocked by pretreatment with atropine, whereas increases induced by pilocarpine (41 mumol kg-1, i.v.) were not blocked by pretreatment with indomethacin, although such increases were inhibited by atropine. This result indicates that secretion of kallikrein stimulated by LTC4 may have been mediated by the successive formation of thromboxane A2 and release of acetylcholine. 4. Intravenous administration of bradykinin (3-30 nmol kg-1) caused a dose-dependent increase in levels of glandular-kallikrein in the bronchial washings. This increase was completely inhibited by pretreatment with atropine, with indomethacin or with an antagonist of thromboxane.5. The increases in levels of glandular-kallikrein in the bronchial washings induced by LTC4 (3 nmol kg'- , i.v.) and pilocarpine (41 flmol kg- 1, i.v.) were significantly inhibited by pretreatment with an antagonist of bradykinin. These results suggest that intravenous LTC4 may increase secretion of glandular-kallikrein via formation of thromboxane A2 and release of acetylcholine in that order, and kinin released by kallikrein may enhance the rate of secretion of glandular-kallikrein.

Increase in the kinin levels in the bronchial washings after intravenous injection of leukotriene C4 in guinea pigs.

In guinea pig plasma, bradykinin (BK) was degraded mainly to des-Arg1-BK by an aminopeptidase-like enzyme, which was inhibited by 2-mercaptoethanol. Besides this degradation, BK was also hydrolyzed by kininase I and kininase II from C-terminal end to des-Arg9-BK, des-Phe8-Arg9-BK and Arg-Pro-Pro-Gly-Phe ([1-5] BK). The formation of des-9-BK was strongly blocked by DL-2-mercaptomethyl-3-guanidinoethylthiopropanoic acid (MGPA) and that of des-8,9-BK and [1-5] BK was inhibited by captopril. When guinea pigs were pretreated with a cocktail of 2-mercaptoethanol, MGPA and captopril, intravenous administration of leukotriene (LT) C4 (10 nmol/kg) caused an increase in the levels of free kinin in the bronchial washings of guinea pigs. This increase was accompanied with the increase in glandular-kallikrein activity, which could be inhibited by aprotinin. As BK is reported to induce both bronchoconstriction and bronchial secretion, the increased free BK induced by LTC4 might enhance the effect of LTC4.

A useful and sensitive method for demonstration of the involvement of either kallikrein-kinin system in pathological states.

In rat carrageenin-induced pleurisy, bradykinin (BK) was hardly able to be detected (< 160 pg per rat) in the exudates. In contrast, des-Phe8-Arg9-BK (des-8,9-BK) level, determined by an enzyme immunoassay (EIA) newly developed, was larger in the exudate and the levels were kept throughout the entire course of this inflammation. Arg-Pro-Pro-Gly-Phe ([1-5] BK) level, measured by an EIA newly developed, was much higher than that of des-8,9-BK in the exudate. Intrapleural administration of soy bean trypsin inhibitor (0.3 mg per rat) reduced the levels of both des-8,9-BK and [1-5] BK in the exudates. Reduction in the residual levels of plasma prekallikrein (P-Kall) and high-molecular-weight-kininogen (HMW-K), not low-molecular-weight-kininogen (LMW-K), were accompanied with increase in these BK degradation products, indicating that plasma prekallikrein was activated in the pleural cavity. On the other hand, intravenous injection of acetaldehyde to rats pretreated with disulfiram resulted in the significant increase in the levels of [1-5] BK in the blood, which was accompanied with reduction in the residual levels of LMW-K, not of HMW-K and P-Kall in plasma. These results indicated that the detection of BK degradation products was a good marker for the kinin release in vivo and that the concomitant reduction of the precursor proteins allowed us to identify the type of kallikrein-kinin systems relevant to the kinin release.

Competitive binding enzyme immunoassay for zonisamide, a new antiepileptic drug, with selected paired-enzyme labeled antigen and antibody.

We assessed the competitive binding between zonisamide (ZNS) in serum samples and beta-galactosidase-labeled ZNS derivatives, using competing antibodies to ZNS derivatives, and selected the best enzyme-labeled antigen and antibody for accurate enzyme immunoassay (EIA) of ZNS in serum without interference from its metabolites or from other antiepileptic drugs. This EIA, based on use of antibody linked to bacterial cell walls, has advantages over HPLC in simplicity, speed (50 samples per hour), and lack of requirement for special equipment. The concentrations of ZNS in serum as measured by the EIA correlated well with those by HPLC (n = 33, r = 0.977).